Category Archives: Stell Cell Research


BridgeBio Pharma to Present Preliminary Findings on its Novel Bioassay Measuring Glycosylated Alpha-dystroglycan (?DG) in Patients with Limb-girdle…

- BridgeBio will also share 15-month Phase 2 data and review the Phase 3 clinical trial design of BBP-418, a potential therapeutic for patients with LGMD2I, with initiation of its Phase 3 study expected in mid-2023

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BridgeBio Pharma to Present Preliminary Findings on its Novel Bioassay Measuring Glycosylated Alpha-dystroglycan (?DG) in Patients with Limb-girdle...

Alvotech to Present Clinical Study Data for AVT04, a Proposed Biosimilar to Stelara®, at 2023 American Academy of Dermatology (AAD) Annual Meeting

REYKJAVIK, Iceland, March 17, 2023 (GLOBE NEWSWIRE) -- Alvotech (NASDAQ: ALVO), a global biotech company specializing in the development and manufacture of biosimilar medicines for patients worldwide, today announced the presentation of two posters related to its clinical studies in support of biosimilarity and clinical comparability of Alvotech’s ATV04 (ustekinumab) and the reference product Stelara® at the 2023 American Academy of Dermatology (AAD) Annual Meeting, March 17-21 in New Orleans.

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Alvotech to Present Clinical Study Data for AVT04, a Proposed Biosimilar to Stelara®, at 2023 American Academy of Dermatology (AAD) Annual Meeting

Sutro Biopharma Announces Inducement Grants Under Nasdaq Listing Rule 5635(c)(4)

SOUTH SAN FRANCISCO, Calif., March 17, 2023 (GLOBE NEWSWIRE) -- Sutro Biopharma, Inc. (Sutro or the Company) (NASDAQ: STRO), a clinical-stage oncology company pioneering site-specific and novel-format antibody drug conjugates (ADCs), today announced that on March 1, 2023, the Compensation Committee of Sutro’s Board of Directors (i) granted to Anne Borgman, M.D. 175,000 shares of Sutro Biopharma stock options and 150,000 restricted stock units (RSUs) of Sutro common stock in connection with her appointment as Sutro’s Chief Medical Officer and (ii) granted 10,000 RSUs of Sutro common stock to one other new employee. These grants were made as an inducement material to the employees’ acceptance of employment with Sutro and were approved by the Compensation Committee of Sutro’s Board of Directors in accordance with Nasdaq Listing Rule 5635(c)(4).

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Sutro Biopharma Announces Inducement Grants Under Nasdaq Listing Rule 5635(c)(4)

Revolutionizing Eye Disease Treatment with iPSC Therapy – geneonline

Revolutionizing Eye Disease Treatment with iPSC Therapy

The Cell & Gene Therapy Research & Development Congress Asia 2023 kicked off in Taipei, Taiwan today, experts in the field of cell and gene therapy gathered here to discuss the emerging advances in the field of cell and gene therapy, the regenerative potential of stem cells, the application of T-cells and CAR-T in the field of immuno-oncology, and more.

Xianmin Zeng, Professor at the University of Singapore and President & CEO of RxCell Inc. gave the talk about iPSC therapy treating retinal degenerative diseases.

Two retinal diseases that lead to blindness are caused by loss of cells: age-related macular degeneration (AMD) and Retinitis pigmentosa (RP). For eye disorders, they are ideal indications for cell therapy regarding eyes accessibility, small and confined organ characteristics.

To develop universal iPSC therapy, RxCell has combined Knock-out and Knock-in gene techniques to generate hypoimmunogenic iPSC cell lines. Mouse model and non-human primate studies show C-Rx-001 presents an effective way to avoid immune rejection. Using autologous cell transplantation and HLA haplobank approach, the single source cell platform possesses the ability to evade immune detection and cure retinal degenerative diseases.

Related Article: Cell & Gene Therapy Congress Asia Day One: Advances in the Research

With clinical applications progressing, Zeng shared that RxCell has established a current Good Manufacture Practice (cGMP) iPSC master cell bank for clinical use. Besides, a GMP-compliant manufacturing process for RPC manufacture has been established.

The cGMP-grade human iPSC-derived retinal photoreceptor precursor cells show no adverse effects in nave NHP models. In addition, photoreceptor precursors injected into retinal degeneration NHP models demonstrated an ability both to survive and to mature into cone photoreceptors at 3 months post-transplant.

Peter Peumans, CTO of IMEC shared the application of deep tech to the healthcare field. As a world-leading R&D and innovation hub in nanoelectronics and digital technologies, IMEC connects digital technology to life science technology, including cell assays, computational microscopy, smart neuroprobes, and next-gen omics.

Peumans noted this new toolset will allow for high-throughput cell selection and editing based on cell surface repertoire or functional assays with single cell precision. For example, IMEC has developed a compact, disposable cell sorter. It enables the sorting of blood cells in minutes, reporting the result to point-of-care and early cancer diagnostics applications.

Following up, Anthony Colenburg Sr, Director & Site Head of Quality from Sutro Biopharma addressed the quality & regulatory expectations of cell & gene therapy products.

In Colenburgs talk, he pointed out the importance of data integrity, since it affects product consistency, safety as well as efficacy.

Colenburg also gave a brief introduction on good data integrity and documentation practice standard. Good Data Integrity and Documentation Practices describe standards by which records are created and maintained. It is required by the U.S. FDA, EMA, as well as other worldwide regulatory guidelines. Not only does it ensure the product safety, identity, strength, quality, and Purity/Potency (SISQP), it also provides evidence to the regulatory agencies that procedures were followed, and the products are being manufactured as claimed. Colenburg emphasized that its important to establish confidence in the quality of manufacturing, testing and final products at every stage/phase.

Exciting Cell & Gene Therapy Research Updates in Glaucoma and Nerve Regeneration

2023-03-08

Developments in Regenerative Medicine: Gene Delivery Tools and Cell Therapy for Parkinsons Disease

2023-03-08

Global Head of Research of Kite Pharma Unveiled the Key Elements to Success in Adoptive Cell Therapy

2023-03-07

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Revolutionizing Eye Disease Treatment with iPSC Therapy - geneonline

Stem cell therapy MSC-NP can ease inflammatory activity in brain… – Multiple Sclerosis News Today

MSC-NP, a form of stem cell therapy thats currently in early clinical trials for multiple sclerosis (MS), can reduce the inflammatory activity of brain immune cells called microglia, according to a new study.

The therapy is known to reduce disease severity and improve myelin regeneration in animal models of MS, and the findings suggest it may be doing so at least in part by modulating the activity of microglia.

This research gives us another important layer in understanding of the efficacy of MSC-NP therapy, and potentially furthers our ability to effectively use this therapy to slow the progression of MS symptoms in patients, Violaine Harris, PhD, a researcher at Tisch Multiple Sclerosis Research Center of New York, and co-author of the study, said in a press release.

Were incredibly excited about this development and the opportunity it presents for us to improve regenerative treatments for MS, Harris said.

The study, Mesenchymal stem cell-derived neural progenitors attenuate proinflammatory microglial activation via paracrine mechanisms, was published in Future Medicine.

Stem cells are a class of cells that are able to grow and differentiate into other cell types. In MSC-NP therapy, a specific class of stem cells called mesenchymal stem cells (MSCs) are collected from a patient.

These stem cells are programmed in the lab to grow into neural progenitor cells (NPs) more specialized stem cells that can grow into neurons and other types of nervous system cells. The MSC-NPs are then injected into a patients nervous system through the spine, called an intrathecal injection.

MSC-NP treatment is notably different from autologous hematopoietic stem cell transplant (aHSCT), which is often referred to as stem cell therapy in MS. aHSCT is a different procedure that aims to replace the stem cells in the bone marrow that give rise to immune cells.

A Phase 1 clinical trial (NCT01933802) sponsored by Tisch tested MSC-NP therapy in 20 people with progressive types of MS, including four with primary progressive MS and 16 with secondary progressive disease. All received a total of three injections of MSC-NP cells, given directly into the spinal canal three months apart.

Results showed that most patients experienced improvements in their functional abilities following the therapy. In some patients, improvements lasted at least two years.

This research gives us another important layer in understanding of the efficacy of MSC-NP therapy, and potentially furthers our ability to effectively use this therapy to slow the progression of MS symptoms in patients.

Tisch is now sponsoring aPhase 2 trial (NCT03355365) testing MSC-NP against a placebo in about 50 progressive MS patients, with the main aim of assessing how the therapy affects measures of disability. Results from the Phase 2 trial are expected this year.

In the recently published study, scientists at Tisch conducted a series of cell experiments aiming to better understand the biological mechanisms by which MSC-NP therapy might be beneficial in MS.

A better understanding of the mechanisms underlying the therapeutic efficacy of MSC-NPs is required in order to optimize this strategy as a treatment for MS, the team wrote.

The researchers specifically investigated how MSC-NPs affect microglia, a type of resident immune cell in the brain and spinal cord. In MS, these cells become activated to promote inflammation, which is thought to contribute to disease progression.

When the researchers grew microglia in the same culture as MSC-NPs, the microglia showed markedly less inflammatory activity, with reduced levels of pro-inflammatory proteins. Instead, the microglia took on properties that are more associated with tissue repair and regeneration.

This study is the first to show that MSC-NPs promote microglial polarization from a proinflammatory to a proregenerative phenotype, the researchers wrote.

Similar results were obtained when the researchers grew MSC-NPs in culture for a time, then removed them and grew microglia in the culture instead. This suggested that the effect of MSC-NPs on microglia was not due to the cells themselves, but rather due to signaling molecules that the MSC-NPs were secreting. This is referred to as paracrine action.

Experiments then revealed a signaling protein called TGF-beta as one of the main modulators of microglia activity. Blocking the activity of TGF-beta, which is made by MSC-NPs, could markedly reduce the anti-inflammatory effect of MSC-NPs on microglia.

The current study gives important insight into the mechanism of action of MSC-NPs on microglia and suggests that at least some of the paracrine action of MSC-NPs can be attributed to TGF-[beta] signaling, the researchers concluded.

As the Tisch Center works toward finding the cause and the cure for MS, this research represents another important milestone in developing even more effective treatments for patients, said Saud Sadiq, MD, study co-author, and director and chief research scientist at the Tisch.

We look forward on building on this research to even further enhance our understanding of MSC-NP therapy and its impact on patients, as well as microglia as a therapeutic target, Sadiq added.

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Stem cell therapy MSC-NP can ease inflammatory activity in brain... - Multiple Sclerosis News Today

Diamyd Medical brings Karin Rosn, M.D, PhD, to its Board of … – PR Newswire

STOCKHOLM, March 10, 2023 /PRNewswire/ --Diamyd Medical today announced that Karin Rosn, M.D, Ph.D, San Francisco, will join the Board of Directors as an adjunct member, and be proposed for election to the Board at its next General Meeting of Shareholders. Dr. Rosn has deep experience from the biotechnology industry with more than two decades of working in senior leadership positions in global clinical development and U.S. and global medical affairs across her time with Horizon Therapeutics, GSK (GlaxoSmithKline), Aimmune Therapeutics and Genentech, a member of the Roche group.

"We are thrilled to welcome Dr. Rosn to Diamyd Medical at this transformative period of the Company", says Ulf Hannelius, CEO of Diamyd Medical. "Karin Rosn's extensive drug development and commercial launch experience spanning a wide variety of indications including immunology, oncology, respiratory and infectious diseases will be invaluable for Diamyd Medical."

"Karin Rosn's impressive track record in developing and launching novel therapeutics as well as her strategic insights regarding the US commercial landscape makes her a strong addition to our Board and Company, says Erik Nerpin, Chairman of Diamyd Medical. "We very much look forward to Dr. Rosn's governance regarding commercial preparations, partner discussions and Diamyd Medical's continued expansion."

"The antigen-specific immunotherapy Diamyd constitutes a potential scientific and therapeutic paradigm shift for the field of type 1 diabetes," says Karin Rosn. "I am impressed by what Diamyd Medical has achieved so far and I am truly honored and excited to be part of this journey."

Dr. Rosn is an accomplished life sciences executive and physician with more than two decades of experience that includes clinical research and development as well as building, leading and successfully launching multiple novel medicines in the United States and globally. At Horizon Therapeutics (acquired by Amgen), Dr Rosn served in dual roles as the Chief Scientific Officer and Executive Vice President of R&D, leading the research and development of biotherapeutics in the areas of autoimmune and inflammatory diseases, including overseeing regulatory filing strategies, having previously served as the senior vice president, U.S. medical affairs at GlaxoSmithKline, where she led a team of more than 300 physicians and medical professionals in areas including immunology, respiratory and inflammation.

Prior to GlaxoSmithKline, Dr. Rosn was senior vice president, U.S. and global medical affairs at Aimmune Therapeutics, Inc. (aquired by Nestl) as well as a member of the clinical development leadership team working on the Phase 2b-3/4 clinical programs and filing strategies for U.S. Food and Drug Administration and European Medicines Agency. Prior to Aimmune, Dr. Rosn was therapeutic area head, immunology, at Genentech, a member of the Roche Group. During her tenure at Genentech, she also served as lead medical director responsible for developing Phase 2-3 clinical programs for multiple biologics in the areas of immunology, respiratory, allergy and dermatology.

Karin Rosn received her medical degree and doctorate from Lund University in Lund, Sweden.

About Diamyd Medical

Diamyd Medical develops precision medicine therapies for Type 1 Diabetes. Diamyd is an antigen-specific immunotherapy for the preservation of endogenous insulin production. DIAGNODE-3, a confirmatory Phase III trial is actively recruting patients with recent-onset Type 1 Diabetes in eight European countries and is being preparedto start recruiting patients in the US this summer. Significant results have previously been shown in a large genetically predefined patient group in a large-scale meta-analysis as well as in the Company's European Phase IIb trial DIAGNODE-2, where the Diamyd was administered directly into a lymph node in children and young adults with recently diagnosed Type 1 Diabetes. A biomanufacturing facility is being set up in Ume for the manufacture of recombinant GAD65, the active ingredient in the antigen-specific immunotherapy Diamyd. Diamyd Medical also develops the GABA-based investigational drug Remygen as a therapy for regeneration of endogenous insulin production and to improve hormonal response to hypoglycaemia. An investigator-initiated Remygen trial in individuals living with Type 1 Diabetes for more than five years is ongoing at Uppsala University Hospital. Diamyd Medical is one of the major shareholders in the stem cell company NextCell Pharma AB as well as in the artificial intelligence company MainlyAI AB.

Diamyd Medical's B-share is traded on Nasdaq First North Growth Market under the ticker DMYD B. FNCA Sweden AB is the Company's Certified Adviser.

For further information, please contact:Ulf Hannelius, President and CEOPhone: +46 736 35 42 41E-mail: [emailprotected]

The following files are available for download:

SOURCE Diamyd Medical AB

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Diamyd Medical brings Karin Rosn, M.D, PhD, to its Board of ... - PR Newswire

Could the Next Blockbuster Drug Be Lab-Rat Free? – The New York Times

In 1937, an American drug company introduced a new elixir to treat strep throat and unwittingly set off a public health disaster. The product, which had not been tested in humans or animals, contained a solvent that turned out to be toxic. More than 100 people died.

The following year, Congress passed the Federal Food, Drug and Cosmetic Safety Act, requiring pharmaceutical companies to submit safety data to the U.S. Food and Drug Administration before selling new medications, helping to usher in an era of animal toxicity testing.

Now, a new chapter in drug development may be beginning. The F.D.A. Modernization Act 2.0, signed into law late last year, allows drug makers to collect initial safety and efficacy data using high-tech new tools, such as bioengineered organs, organs on chips and even computer models, instead of live animals. Congress also allocated $5 million to the F.D.A. to accelerate the development of alternatives to animal testing.

Other agencies and countries are making similar shifts. In 2019, the U.S. Environmental Protection Agency announced that it would reduce, and eventually aim to eliminate, testing on mammals. In 2021, the European Parliament called for a plan to phase out animal testing.

These moves have been driven by a confluence of factors, including evolving views of animals and a desire to make drug development cheaper and faster, experts said. But what is finally making them feasible is the development of sophisticated alternatives to animal testing.

It is still early for these technologies, many of which still need to be refined, standardized and validated before they can be used routinely in drug development. And even advocates for these alternatives acknowledge that animal testing is not likely to disappear anytime soon.

But momentum is building for non-animal approaches, which could ultimately help speed drug development, improve patient outcomes and reduce the burdens borne by lab animals, experts said.

Animals are simply a surrogate for predicting whats going to happen in a human, said Nicole Kleinstreuer, director of the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods.

If we can get to a place where we actually have a fully human-relevant model, she added, then we dont need the black box of animals anymore.

Animal rights groups have been lobbying for a reduction in animal testing for decades, and they have found an increasingly receptive public. In a 2022 Gallup poll, 43 percent of Americans said that medical testing on animals was morally wrong, up from 26 percent in 2001.

Reducing animal testing matters to so many people for so many different reasons, said Elizabeth Baker, the director of research policy at the Physicians Committee for Responsible Medicine, a nonprofit group that advocates for alternatives to animal testing. Animal ethics is actually quite a big driver.

But it is not the only one. Animal testing is also time-consuming, expensive and vulnerable to shortages. Drug development, in particular, is rife with failures, and many medications that appear promising in animals do not pan out in humans. Were not 70-kilogram rats, said Dr. Thomas Hartung, who directs the Johns Hopkins Center for Alternatives to Animal Testing.

Moreover, some cutting-edge new treatments are based on biological products, such as antibodies or fragments of DNA, which may have targets that are specific to humans.

Theres a lot of pressure, not just for ethical reasons, but also for these economical reasons and for really closing safety gaps, to adapt to things which are more modern and human relevant, Dr. Hartung said.

(Dr. Hartung is the named inventor on a Johns Hopkins University patent on the production of brain organoids. He receives royalty shares from, and consults for, the company that has licensed the technology.)

In recent years, scientists have developed more sophisticated ways to replicate human physiology in the laboratory.

They have learned how to coax human stem cells to assemble themselves into a small, three-dimensional clump, known as an organoid, that displays some of the same basic traits as a specific human organ, such as a brain, a lung or a kidney.

Scientists can use these mini-organs to study the underpinnings of disease or to test treatments, even on individual patients. In a 2016 study, researchers made mini-guts from cell samples from patients with cystic fibrosis and then used the organoids to predict which patients would respond to new drugs.

Scientists are also using 3-D printers to produce organoids at scale and to print strips of other kinds of human tissue, such as skin.

Another approach relies on organs on a chip. These devices, which are roughly the size of AA batteries, contain tiny channels that can be lined with different kinds of human cells. Researchers can pump drugs through the channels to simulate how they might travel through a particular part of the body.

In one recent study, the biotech company Emulate, which makes organs on chips, used a liver-on-a-chip to screen 27 well-studied drugs. All of the drugs had passed initial animal testing, but some had later turned out to cause liver toxicity in humans. The liver-on-a-chip successfully flagged as many as 87 percent of the toxic compounds, the researchers reported in Communications Medicine last December.

Researchers can also link different systems together, connecting a heart-on-a-chip to a lung-on-a-chip to a liver-on-a-chip, to study how a drug might affect the entire interconnected system. Thats where I think the future lies, Dr. Kleinstreuer said.

Not all the new tools require real cells. There are also computational models that can predict whether a compound with certain chemical characteristics is likely to be toxic, how much of it will reach different organs and how quickly it will be metabolized.

The models can be adjusted to represent different types of patients. For instance, a drug developer could test whether a medication that works in young adults would be safe and effective in older adults, who often have reduced kidney function.

If you can identify the problems as early as possible using a computational model that saves you going down the wrong route with these chemicals, said Judith Madden, an expert on in silico, or computer-based, chemical testing at Liverpool John Moores University. (Dr. Madden is also the editor in chief of the journal Alternatives to Laboratory Animals.)

Some of the approaches have been around for years, but advances in computing technology and artificial intelligence are making them increasingly powerful and sophisticated, Dr. Madden said.

Virtual cells have also shown promise. For instance, researchers can model individual human heart cells using a set of equations that describe everything thats going on in the cell, said Elisa Passini, the program manager for drug development at the National Center for the Replacement, Refinement and Reduction of Animals in Research, or NC3Rs, in Britain.

In a 2017 study, Dr. Passini, then a researcher at the University of Oxford, and her colleagues concluded that these digital cells were better than animal models at predicting whether dozens of known drugs would cause heart problems in humans.

Scientists are now building entire virtual organs, which could eventually be linked together into a sort of virtual human, Dr. Passini added, though some of the work remains in early stages.

In the short term, a virtual lab animal might be more achievable, said Cathy Vickers, the head of innovation at NC3Rs, which is working with scientists and pharmaceutical companies to develop a digital model of a dog that could be used for drug toxicity testing.

Its still a big push to develop a virtual dog, Dr. Vickers said. But its about building that capacity, building that momentum.

Many potential animal alternatives will require more investment and development before they can be used widely, experts said. They also have limitations of their own. Computer models, for instance, are only as good as the data they are built on, and more data is available on certain types of compounds, cells and outcomes than others.

For now, these alternative methods are better at predicting relatively simple, short-term outcomes, such as acute toxicity, than complicated, long-term ones, such as whether a chemical might increase the risk of cancer when used over months or years, scientists said.

And experts disagreed on the extent to which these alternative approaches might replace animal models. Were absolutely working toward a future where we want to be able to fully replace them, Dr. Kleinstreuer said, although she acknowledged that it might take decades, if not centuries.

But others said that these technologies should be viewed as a supplement to, rather than a replacement for, animal testing. Drugs that prove promising in organoids or computer models should still be tested in animals, said Matthew Bailey, president of the National Association for Biomedical Research, a nonprofit group that advocates for the responsible use of animals in research.

Researchers still need to be able to see everything that happens in a complex mammalian organism before being allowed to move to the human clinical trials, he said.

Still, even this more conservative approach could have benefits, said Nicole zur Nieden, a developmental toxicologist at the University of California, Riverside, who said that she thought the wholesale replacement of animal testing was unrealistic.

In particular, she said, the new approaches could help scientists screen out a greater number of ineffective and unsafe compounds before they ever get to animal trials. That would reduce the number of animal studies researchers need to conduct and the limit the chemicals lab animals are exposed to, she said, adding, We will be able to reduce the suffering of test animals quite tremendously.

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Could the Next Blockbuster Drug Be Lab-Rat Free? - The New York Times

HISTOGEN INC. Management’s Discussion and Analysis of Financial Condition and Results of Operations. (form 10-K) – Marketscreener.com

The following discussion and analysis of our financial condition and results ofoperations should be read in conjunction with our audited consolidated financialstatements and related notes thereto included elsewhere in this Annual Report onForm 10-K for the period ended December 31, 2022. As further described in Note1of the notes to our consolidated financial statements included elsewhere inthis Annual Report, Private Histogen was determined to be the accountingacquirer in the Merger. In addition, references to the Company's operatingresults prior to the Merger will refer to the operating results of PrivateHistogen. Except as otherwise indicated herein or as the context otherwiserequires, references in this Annual Report on Form 10-K to "Histogen" "theCompany," "we," "us" and "our" refer to Histogen Inc., a Delaware corporation,on a post-Merger basis, and the term "Private Histogen" refers to the businessof privately-held Histogen Inc. prior to completion of the Merger. The followingdiscussion and analysis of our financial condition and results of operationscontains forward-looking statements that involve a number of risks,uncertainties and assumptions. Actual events or results may differ materiallyfrom our expectations. Important factors that could cause actual results todiffer materially from those stated or implied by our forward-looking statementsinclude, but are not limited to, those set forth in the "Risk Factors" sectionof this annual report, many of which are outside of our control. Allforward-looking statements included in this annual report are based oninformation available to us as of the time we file and, except as required bylaw, we undertake no obligation to update publicly or revise any forward-lookingstatements.

Overview

We are clinical-stage therapeutics company focused on developing potentialfirst-in-class clinical and preclinical small molecule pan-caspase and caspaseselective inhibitors that protect the body's natural process to restore immunefunction. Our product candidates include emricasan, CTS-2090 and CTS-2096.Currently, we are developing emricasan for acute bacterial skin and skinstructure infections (ABSSSI) as well evaluating its use for other infectiousdiseases. Our pipeline also includes novel preclinical product candidatesincluding CTS-2090 and CTS-2096, which are highly selective small moleculeinhibitors of caspase-1 designed for the treatment of certain inflammatorydiseases.

Previously, our focus was on developing our proprietary hypoxia-generated growthfactor technology platform and stem cell-free biologic products as potentialfirst-in-class restorative therapeutics that ignite the body's natural processto repair and maintain healthy biological function. In December 2022, weannounced termination of our HST-003 study for futility related to patientrecruitment and due to pipeline reprioritization, in the third quarter of 2022,we suspended all IND enabling activities on our HST-004 program.

While we are actively seeking collaboration partners or acquirors for our HumanMultipotent Cell Conditioned Media, or CCM and our Human Extracellular Matrix,or hECM, there are no assurances that we will find a collaboration partner oracquirer for CCM or hECM or that the terms and timing of any such arrangementswould be acceptable to us.

Components of Results of Operations

Revenue

Our revenues to date have been generated primarily from the sale of cosmeticingredient products ("CCM"), license fees, professional services revenue, and aNational Science Foundation grant award.

License and Product Revenue

Our license and product revenue to date has been generated primarily frompayments received under the Allergan Agreements.

Grant Revenue

In March 2017, the National Science Foundation ("NSF"), a government agency,awarded us a research and development grant to develop a novel wound dressingfor infection control and tissue regeneration. As of March 31, 2021, wecompleted all obligations under the NSF grant and, as such, no longer generateany revenue in connection with the research and development grant.

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Cost of product revenue represents direct and indirect costs incurred to bringthe product to saleable condition, including write-offs of inventory.

Research and Development

Research and development expenses consist primarily of costs incurred for thepreclinical and clinical development of our product candidates, which include:

expenses under agreements with third-party contract organizations, investigativeclinical trial sites that conduct research and development activities on ourbehalf, and consultants;

costs related to develop and manufacture preclinical study and clinical trialmaterial;

salaries and employee-related costs, including stock-based compensation;

costs incurred and reimbursed under our grant awarded by the U.S. Department ofDefense ("DoD") to partially fund our Phase 1/2 clinical trial of HST-003 forregeneration of cartilage in the knee;

costs incurred for IND enabling activities for HST-004 for spinal disc repair;

costs incurred for completing the feasibility assessment of emricasan for thepotential treatment of skin bacterial infections including those related toABSSSI's, as well as other infectious diseases; and

laboratory and vendor expenses related to the execution of preclinical andclinical trials.

We accrue all research and development costs in the period for which they areincurred. Costs for certain development activities are recognized based on anevaluation of the progress to completion of specific tasks using information anddata provided to us by our vendors, collaborators and third-party serviceproviders. Advance payments for goods or services to be received in futureperiods for use in research and development activities are deferred and thenexpensed as the related goods are delivered and as services are performed.

We expect our research and development expenses to increase substantially forthe foreseeable future as we: (i) invest in additional operational personnel tosupport our planned product development efforts, and (ii) continue to invest indeveloping our product candidates as our product candidates advance into laterstages of development, and as we begin to conduct larger clinical trials.Product candidates in later stages of clinical development generally have higherdevelopment costs than those in earlier stages of clinical development,primarily due to the increased size and duration of later-stage clinical trials.

Our direct research and development expenses are tracked by product candidateand consist primarily of external costs, such as fees paid under third-partylicense agreements and to outside consultants, contract research organizations("CROs"), contract manufacturing organizations and research laboratories inconnection with our preclinical development, process development, manufacturingand clinical development activities. We do not allocate employee costs and costsassociated with our discovery efforts, laboratory supplies and facilities,including other indirect costs, to specific product candidates because thesecosts are deployed across multiple programs and, as such, are not separatelyclassified. We use internal resources primarily to conduct our research as wellas for managing our preclinical development, process development, manufacturingand clinical development activities. These employees work across multipleprograms and, therefore, we do not track our costs by product candidate unlesssuch costs are

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includable as subaward costs. The following table shows our research anddevelopment expenses by type of activity (in thousands):

Total research and development expenses $ 5,021 $ 8,473

We cannot determine with certainty the timing of initiation, the duration or thecompletion costs of current or future preclinical studies and clinical trials ofour product candidates due to the inherently unpredictable nature of preclinicaland clinical development, including any potential expanded dosing beyond theoriginal protocols based in part on ongoing clinical success. Clinical andpreclinical development timelines, the probability of success and developmentcosts can differ materially from expectations. We anticipate that we will makedeterminations as to which product candidates to pursue and how much funding todirect to each product candidate on an ongoing basis in response to the resultsof ongoing and future preclinical studies and clinical trials, regulatorydevelopments and our ongoing assessments of each product candidate's commercialpotential. We will need to raise substantial additional capital in the future.In addition, we cannot forecast which product candidates may be subject tofuture collaborations, when such arrangements will be secured, if at all, and towhat degree such arrangements would affect our development plans and capitalrequirements.

General and Administrative

General and administrative expenses consist primarily of personnel-relatedcosts, insurance costs, facility costs and professional fees for legal, patent,consulting, investor and public relations, accounting and audit services.Personnel-related costs consist of salaries, benefits, and stock-basedcompensation. We expect our general and administrative expenses to increasesubstantially as we: (i) incur additional costs associated with being a publiccompany, including audit, legal, regulatory, and tax-related services associatedwith maintaining compliance with exchange listing and SEC requirements, directorand officer insurance premiums, and investor relations costs, (ii) hireadditional personnel, and (iii) protect our intellectual property.

Other Income (Expense)

Interest Income

Interest income consists of interest earned on our cash equivalents, whichconsist of money market funds. Our interest income has not been significant dueto low interest earned on invested balances.

Other Income

Other income primarily consists of the Paycheck Protection Program Loan forgivenby the Small Business Administration on May 21, 2021.

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Results of Operations

Comparison of Years Ended December 31, 2022 and 2021

The following table sets forth our selected statements of operations data forthe years ended December 31, 2022 and 2021 (in thousands):

For the years ended December 31, 2022 and 2021, we recognized license revenuesof $3.8 million and $27 thousand, respectively. The increase in the currentperiod is due to a one-time payment of $3.75 million received in March 2022 asconsideration for execution of the Allergan Letter Agreement.

For the years ended December 31, 2022 and 2021, we recognized product revenuesof $0 and $0.9 million, respectively. The product revenue for the year endedDecember 31, 2021 was due to a one-time unanticipated sale of CCM to Allergan,unrelated to the Allergan Agreements. As of March 31, 2021, all obligations ofthe Company related to the additional supply of CCM to Allergan under theAllergan Agreements had been completed.

For the years ended December 31, 2022 and 2021, we recognized grant revenue of$0 and $0.1 million, respectively. The grant revenue for 2021 is associated witha research and development grant awarded to the Company from the NSF. As ofMarch 31, 2021, all work required by the Company under the grant has beencompleted.

For the years ended December 31, 2022 and 2021, we recognized $0 and $0.2million, respectively, for cost of product sold to Allergan under the AllerganAgreements.

Research and Development Expenses

Research and development expenses for the years ended December 31, 2022 and 2021were $5.0 million and $8.5 million, respectively. The decrease of $3.5 millionwas primarily due to decreases in personnel related expenses, the number ofclinical and preclinical candidates in development and corresponding reductionof costs, partially offset by facility rent increases.

General and Administrative Expenses

General and administrative expenses for the years ended December 31, 2022 and2021 were $9.4 million and $7.8 million, respectively. The increase of $1.6million was primarily due to increases in royalty expenses, legal fees,

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outside services, rent expenses and personnel expenses, partially offset byreductions in insurance and other administrative expenses.

Liquidity and Capital Resources

From inception through December 31, 2022, we have an accumulated deficit of$88.3 million and expect to incur operating losses and generate negative cashflows from operations for the foreseeable future. As of December 31, 2022, wehad approximately $12.1 million in cash and cash equivalents.

We have not yet established ongoing sources of revenues sufficient to cover ouroperating costs and will need to continue to raise additional capital to supportour future operating activities, including progression of our developmentprograms, preparation for potential commercialization, and other operatingcosts. Our plans with regard to these matters include entering into acombination of additional debt or equity financing arrangements, strategicpartnerships, collaboration and licensing arrangements, or other similararrangements. There can be no assurance that we will be able to obtainadditional financing on terms acceptable to us, on a timely basis or at all. Theaforementioned factors raise substantial doubt about our ability to continue asa going concern.

The consolidated financial statements have been prepared assuming that theCompany will continue as a going concern, which contemplates the realization ofassets and the satisfaction of liabilities and commitments in the normal courseof business. Based on the current business plan and operating budget, there issubstantial doubt about the Company's ability to continue as a going concernwithin one year from the date the consolidated financial statements are issued.The consolidated financial statements do not include any adjustments to reflectthe possible future effects on the recoverability and classification of assetsor the amounts and classification of liabilities that may result from theoutcome of this uncertainty.

Redeemable Convertible Preferred Stock

March 2022 Offering of Preferred Stock

As described in Note 7 to the consolidated financial statements, in March 2022,the Company completed a private placement offering (the "March 2022 Offering")of Series A Preferred Stock and Series B Preferred Stock. The proceeds of $4.76million were held in escrow and were only permitted to be disbursed to theCompany upon conversion of the Series A and Series B Preferred Stock.

Between June 2, 2022, and June 29, 2022, the Company redeemed for cash proceedstotaling $5,250,500, 2,500 outstanding shares of Series A Preferred Stock and2,500 outstanding shares of Series B Preferred Stock based on the receipt of theRedemption Notices (the "Preferred Redemption") at a price equal to 105% of the$1,000 stated value per share.

As of December 31, 2022, all shares of the Series A and B Preferred Stock are nolonger outstanding and the Company's only class of outstanding stock is itscommon stock. No proceeds were received from the March 2022 Offering.

Common Stock

January 2021 Offering of Common Stock

In January 2021, the Company completed an S-1 offering (the "January 2021Offering") of an aggregate of 580,000 shares of common stock, pre-fundedwarrants to purchase up to 120,000 shares of its common stock, and common stockwarrants to purchase up to an aggregate of 700,000 shares of common stock. Tothe extent that an investor determines, at their sole discretion, that theywould beneficially own in excess of the Beneficial Ownership Limitations (or assuch investor may otherwise choose), in lieu of purchasing shares of CommonStock and Common Warrants, such investor could have elected to purchasePre-Funded Warrants and Common Warrants at the Pre-Funded Purchase Price in lieuof the shares of Common Stock and Common Warrants in such a manner to result inthe same aggregate purchase price being paid by such investor to the Company.The combined purchase price of one share of common stock and the accompanyingcommon stock warrant was $20.00, and the combined purchase price of onepre-funded

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warrant and accompanying common stock warrant was $19.998. The common stockwarrants are exercisable for five (5) years at an exercise price of $20.00 pershare. The pre-funded warrants are immediately exercisable at an exercise priceof $0.002 per share and may be exercised at any time until all of the pre-fundedwarrants are exercised in full. Placement agent warrants were issued to purchaseup to 35,000 shares of common stock, are immediately exercisable for an exerciseprice of $25.00, and are exercisable for five (5) years following the date ofissuance. The Company received gross proceeds of $14.0 million and incurredplacement agent's fees and other offering expenses of approximately $1.9million.

As of December 31, 2022, a total of 336,060 warrants issued in the January 2021Offering to purchase shares of common stock have been exercised and the Companyissued 336,060 shares of its common stock. The Company received gross proceedsof approximately $6.8 million.

As of December 31, 2022, the Company had 387,565 shares and 11,375 shares ofcommon stock reserved for issuance pursuant to the warrants and placementagent's warrants, respectively, issued by the Company in the January 2021Offering, at an exercise price of $20.00 per share and $25.00 per share,respectively.

June 2021 Offering of Common Stock

In June 2021, the Company completed a registered direct offering (the "June 2021Offering") of an aggregate of 298,865 shares of common stock, together withaccompanying warrants to purchase up to an aggregate of 239,093 shares of commonstock, at a public offering price of $22.00 per share. The accompanying warrantspermit the investor to purchase additional shares equal to 80% of the number ofshares of the Company's common stock purchased by the investor. The warrantshave an exercise price of $20.00 per share, are immediately exercisable, andexpire five and a half (5.5) years following the date of issuance. In addition,the Company's placement agent was issued compensatory warrants equal to 5.0%, or14,946 shares, of the aggregate number of common stock sold in the offering,which are immediately exercisable for an exercise price of $27.50 and expirefive (5) years following the date of issuance on June 7, 2026. The Companyreceived gross proceeds of $6.6 million and incurred cash-based placement agentfees and other offering expenses of approximately $0.9 million.

As of December 31, 2022, no warrants associated with the June 2021 Offering havebeen exercised.

As of December 31, 2022, the Company had 90,910 shares and 14,946 shares ofcommon stock reserved for issuance pursuant to the warrants and placementagent's warrants, respectively, issued by the Company in the June 2021 Offering,at an exercise price of $20.00 per share and $27.50 per share, respectively. Inconnection with the July 2022 Offering, the Company agreed to amend warrants, byreducing the exercise price and extending the expiration date, to purchase up toan aggregate of 148,183 shares of common stock of the Company that wereoriginally issued to the investor in the June 2021 Offering.

December 2021 Offering of Common Stock

In December 2021, the Company completed a registered direct offering (the"December 2021 Offering") of an aggregate of 411,764 shares of common stock and411,766 warrants to purchase up to 411,766 shares of common stock, at a publicoffering price of $8.50 per share. The accompanying warrants permit the investorto purchase additional shares equal to approximately the same number of sharesof the Company's common stock purchased by the investor. The warrants have anexercise price of $8.50 per share, may be exercised any time on or after 6months and one (1) day after the issuance date, and expire five and a half (5.5)years following the date of issuance. In addition, the Company's placement agentwas issued compensatory warrants equal to 5.0%, or 20,590 shares, of theaggregate number of shares of common stock sold in the offering, which areimmediately exercisable for an exercise price of $10.626 and expire five and ahalf (5.5) years following the date of issuance on June 21, 2027. The Companyreceived gross proceeds of $3.5 million and incurred cash-based placement agentfees and other offering expenses of approximately $0.5 million.

As of December 31, 2022, no warrants associated with the December 2021 Offeringhave been exercised.

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As of December 31, 2022, the Company had 164,707 shares and 20,590 shares ofcommon stock reserved for issuance pursuant to the warrants and placementagent's warrants, respectively, issued by the Company in the December 2021Offering, at an exercise price of $8.50 per share and $10.626 per share,respectively. In connection with the July 2022 Offering, the Company agreed toamend warrants, by reducing the exercise price and extending the expirationdate, to purchase up to an aggregate of 247,059 shares of common stock of theCompany that were originally issued to the investor in the December 2021Offering.

July 2022 Offering of Common Stock

On July 12, 2022, the Company entered into a Securities Purchase Agreement (the"July 2022 Purchase Agreement") with a single healthcare-focused institutionalinvestor for the sale by the Company of (i) a pre-funded warrant to purchase upto 1,774,309 shares of Common Stock (the "Pre-Funded Warrant"), (ii) a Series Awarrant to purchase up to an aggregate of 1,774,309 shares of common stock (the"Series A Warrant"), and (iii) a Series B warrant to purchase up to an aggregateof 1,774,309 shares of common stock (the "Series B Warrant," and together withthe Pre-Funded Warrant and the Series A Warrant, the "Warrants"), in a privateplacement offering (the "Offering"). The combined purchase price of onePre-Funded Warrant and accompanying Series A Warrant and accompanying Series BWarrant was $2.818.

Subject to certain ownership limitations, the Series A Warrant is exercisableimmediately after the issuance date at an exercise price equal to $2.568 pershare of common stock, subject to adjustments as provided under the terms of theSeries A Warrant, and has a term of five and a half (5.5) years from theissuance date. Subject to certain ownership limitations, the Series B Warrant isexercisable immediately after the issuance date at an exercise price equal to$2.568 per share of common stock, subject to adjustments as provided under theterms of the Series B Warrant, and has a term of one and a half (1.5) years fromthe issuance date. Subject to certain ownership limitations described in thePre-Funded Warrant, the Pre-Funded Warrant was immediately exercisable and maybe exercised at an exercise price of $0.0001 per share of common stock any timeuntil all of the Pre-Funded Warrant is exercised in full. As of December 31,2022, the Pre-Funded Warrant to purchase up to an aggregate of 1,774,309 sharesof common stock had been fully exercised and the Company issued 1,774,309 sharesof common stock.

The Company also agreed to amend certain warrants to purchase up to an aggregateof 447,800 shares of common stock of the Company that were issued to theinvestor in the private placement in November 2020, June 2021 and December 2021with exercise prices ranging from $8.50 to $34.00 per share and expiration datesranging from May 18, 2026 to June 21, 2027, so that such warrants have a reducedexercise price of $2.568 per share and expiration date of five and a half (5.5)years following the closing of the private placement, for an additional offeringprice of $0.0316 per amended warrant. The incremental fair value resulting fromthe modifications to the warrants was adjusted against the gross proceeds fromthe offering as an equity issuance cost.

The gross proceeds to the Company were approximately $5 million, beforededucting the placement agent's fees and other offering expenses, and excludingthe proceeds, if any, from the exercise of the Series A Warrant, the Series BWarrant, and amended warrants.

As of December 31, 2022, no warrants associated with the July 2022 PurchaseAgreement have been exercised.

As of December 31, 2022, the Company had 3,996,418 shares and 124,202 shares ofcommon stock reserved for issuance pursuant to the warrants and placementagent's warrants, respectively, issued by the Company in the July 2022 PurchaseAgreement, at an exercise price of $2.568 per share and $3.5225 per share,respectively.

Common Stock Purchase Agreement with Lincoln Park

In July 2020, the Company entered into a common stock purchase agreement (the"2020 Purchase Agreement") with Lincoln Park which provided that, upon the termsand subject to the conditions and limitations in the 2020 Purchase Agreement,Lincoln Park was committed to purchase up to an aggregate of $10.0 million ofshares of the Company's common stock at the Company's request from time to timeduring a 24 month period that began in July 2020 and at prices based on themarket price of the Company's common stock at the time of each sale. Uponexecution of the 2020 Purchase Agreement, the Company sold 16,425 shares ofcommon stock at $60.88 per share to Lincoln Park for gross

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proceeds of $1.0 million. During the year ended December 31, 2020, the Companysold an additional 15,000 shares of common stock to Lincoln Park for grossproceeds of approximately $0.5 million. In addition, in consideration forentering into the 2020 Purchase Agreement and concurrently with the execution ofthe 2020 Purchase Agreement, the Company issued 3,348 shares of its common stockto Lincoln Park. During the year ended December 31, 2022, the Company did notsell any shares of common stock to Lincoln Park.

The 2020 Purchase Agreement expired automatically pursuant to its term on August1, 2022, and the Company did not sell any additional shares of common stock toLincoln Park through the date of expiration of the 2020 Purchase Agreement.

Common Stock Warrants

In 2016, Private Histogen issued warrants to purchase common stock asconsideration for settlement of prior liability claims. The warrants for thepurchase of up to 180 common shares at an exercise price of $461.60 per shareexpired on July 31, 2021.

In addition, as of December 31, 2022, warrants to purchase 68 shares of commonstock with an exercise price of $1,486.00 per share remain outstanding that wereissued by Conatus in connection with obtaining financing in 2016. These warrantsexpire on July 3, 2023.

See warrant discussion above in connection with the January 2021 Offering, theJune 2021 Offering, the December 2021 Offering, and the July 2022 Offering.

Cash Flow Summary for the Years Ended December 31, 2022 and 2021

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HISTOGEN INC. Management's Discussion and Analysis of Financial Condition and Results of Operations. (form 10-K) - Marketscreener.com

SEELOS THERAPEUTICS, INC. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS (form 10-K) – Marketscreener.com

Overview

Impact of COVID-19

Our product development pipeline is as follows:

Table of Contents

Additionally, we are developing several preclinical programs, most of which havewell-defined mechanisms of action, including SLS-004, licensed from DukeUniversity, and SLS-007, licensed from The Regents of the University ofCalifornia, for the potential treatment of Parkinson's Disease ("PD").

Strategy and Ongoing Programs

Table of Contents

? advancing SLS-002 in ASIB in MDD and post-traumatic stress disorder;

? advancing SLS-004 in PD;

? advancing SLS-005 in ALS, SCA, HD and Sanfilippo Syndrome;

? advancing new formulations of SLS-005 in neurological diseases; and

? acquiring synergistic assets in the CNS therapy space through licensing and

partnerships.

Operating expense for the years ended December 31, 2022 and 2021 was as follows(in thousands, except percentages):

Research and Development Expenses

General and Administrative Expenses

Other Income and Expense

369

(3,247)

2,387

(149)

Interest Expense

Interest expense was $14,000 and $1.6 million for the years ended December 31,2022 and 2021, respectively. The decrease was due to our repayment of theDecember 2020 convertible notes during 2021.

Change in Fair Value of Derivative Liability

Change in Fair Value of Convertible Notes

Net Loss on Extinguishment of Debt

Gain on Forgiveness of Debt

Gain on forgiveness of debt was $0 and $149,000 for the years ended December 31,2022 and 2021, respectively. This gain was due to the forgiveness of ouroutstanding PPP loan, which we received in June 2021.

Change in Fair Value of Warrant Liability

Liquidity, Capital Resources and Financial Condition

We expect to use the net proceeds from the above transactions primarily forgeneral corporate purposes, which may include financing our normal businessoperations, developing new or existing product candidates, and funding capitalexpenditures, acquisitions and investments.

Table of Contents

Our future liquidity and capital funding requirements will depend on numerousfactors, including:

? our ability to raise additional funds to finance our operations;

? our ability to maintain compliance with the listing requirements of The Nasdaq

Capital Market;

? the outcome, costs and timing of any clinical trial results for our current or

future product candidates;

? potential litigation expenses;

? the emergence and effect of competing or complementary products or product

property portfolio, including the amount and timing of any payments we may be

? required to make, or that we may receive, in connection with the licensing,

filing, prosecution, defense and enforcement of any patents or other

intellectual property rights;

? our ability to retain our current employees and the need and ability to hire

additional management and scientific and medical personnel;

? the terms and timing of any collaborative, licensing or other arrangements that

we have or may establish;

? the trading price of our common stock; and

? our ability to increase the number of authorized shares outstanding to

facilitate future financing events.

Cash Flow Summary

(48,995)

Net cash (used in) provided by financing activities (1,597) 112,067Net (decrease) increase in cash

No cash was used in investing activities during the years ended December 31,2022 or 2021.

Cash provided by financing activities of $112.1 million in the year endedDecember 31, 2021 was primarily due to the proceeds from our May 2021 andJanuary 2021 public offerings, as well as proceeds from the issuance and sale ofthe 2021 Note and the 2021 Closing Shares.

Contractual Obligations

Recent Accounting Pronouncements

See Note 1 to our consolidated financial statements for a discussion of recentaccounting pronouncements and their effect, if any, on us.

Critical Accounting Estimates and Policies

We believe that the following critical accounting policies and estimates have ahigher degree of inherent uncertainty and require our most significantjudgments:

Accrual of Research and Development Expenses

Valuation of Warrant Liability

Valuation of Convertible Notes

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SEELOS THERAPEUTICS, INC. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS (form 10-K) - Marketscreener.com

Combined adipose-derived mesenchymal stem cell and antibiotic … – Nature.com

Bacteria and biofilm formation

MSSA strain ATCC29213 (American Type Culture Collection, Manassas, VA, USA) was used as it tends to form biofilms32,33. MSSA was streaked onto plates containing tryptic soy broth and Bacto agar (BD Biosciences, Franklin Lakes, NJ, USA) and grown overnight in 5 mL of tryptic soy broth at 37 C in a shaking incubator. MSSA cells in the incubation medium were grown to the early exponential growth phase (0.20.3 optical density at 600 nm), corresponding to 5.0 107 CFU/mL.

Adipose tissue (~1.5 g) was obtained from Wistar rats (female; 12 weeks old; Japan SLC Corp., Shizuoka, Japan). ADSCs were prepared by modifying previously reported methods34. Further details can be found in the Supplementary file. Cellular characteristics (i.e. expression of stem cell surface markers) were determined using flow cytometric analysis after labeling ADSCs with appropriate antibodies of cultivation.

Wistar rats (female; 12 weeks old; Japan SLC Corp.) were housed under specific pathogen-free conditions with a 12-h light/dark cycle and ad libitum access to a certified diet (CRF-1; Oriental Yeast Corp., Tokyo, Japan) and water (chlorine concentration; 10 ppm). The drinking, feeding behavior, and body weight of the rats were monitored regularly. The animals were acclimatized for 7 days before undergoing the implant operation.

Rats were anesthetized with midazolam (2.5 mg/kg; Astellas Pharma, Tokyo, Japan), medetomidine (0.5 mg/kg; Zenoaq, Fukushima, Japan), and butorphanol tartrate (2.5 mg/kg; Meiji Seika Pharma, Tokyo, Japan). To establish infection, A medical-grade K-wire (1.2 mm diameter; Synthes Inc., West Chester, PA, USA) was incubated in an overnight culture with MSSA strain ATCC29213 and then air-dried for 20min prior to insertion. This MSSA strain exposure coats the screw with 5107 CFU. The K-wire was surgically placed into the distal femur as previously described34,35,36. Briefly, the skin overlying the leg was shaved and cleaned with iodine solution. A medial parapatellar approach was used, and the patella was dislocated laterally to access the knee joint. The femoral medullary canal was reamed with an 18-gauge needle and the K-wire was placed in a retrograde fashion with 1 mm of the wire protruding into the joint space. The quadriceps-patellar complex was reduced to the anatomic position, and the wound was closed with nylon 4-0 sutures. Rats were randomly assigned and equally divided into three groups: no-treatment, antibiotic (ciprofloxacin [3.0 mg/kg per day intravenously]), and ADSCs [5.0 105 cells intravenously 30 min, 6 h, and 18 h after the surgical procedure]) with antibiotic (ciprofloxacin [3.0 mg/kg per day intravenously] groups. The ADSC dose, based on a previous report37, is considered to not induce adverse effects, including a high mortality rate. Additionally, a previous report showed that a ciprofloxacin dose of 3.0 mg/kg per day caused no adverse effects or unstable conditions in rats11. MSSA induced infection in 100% of the untreated rats with no significant differences in the initial body weights between the different groups.

After evaluating the general overall condition and soft tissue swelling, the rats were euthanized on POD 14 using thiopental sodium (100 mg/kg body weight). Tissues from the knee joint space, femur, and implant were harvested in a sterile manner for ex vivo analyses.

Weight change (n = 6 rats per group) was calculated as a percentage change based on the preoperative weight to quantitatively measure the systemic response to infection. Preoperative baseline measurements were performed on the day before surgery. The weight of the rats was also evaluated on PODs 1, 3, 7, and 14.

Soft tissue and bone damage (n = 6 rats per group) on POD14 was scored by three examiners (D.I, A.T. and T.K.) blinded to the rats according to a modified Rissing scoring38,39. Further details can be found in Supplementary file.

CT imaging (n = 6 rats per group) was performed on POD14 to determine the degree of infection within the femoral region of interest. Considering that image artifacts from the K-wires may cause artifacts in the reconstructed CT images, isolated femurs from rats with the wire removed were subjected to CT scanning (LaTheta LCT-200; Hitachi Aloka Medical, Tokyo, Japan), operating at 50 kV and 0.5 mA (radiation exposure remained below 40 mSv). BMD was calculated automatically using LaTheta software (version 3.51). Reconstructed CT images were initially visualized in three dimensions (3D) to evaluate changes in bone morphology resulting from implant infection. A threshold-limited 3D rendering was created to visualize bone damage.

Implants were harvested (n = 6 rats per group) from each group. Based on a previous report, the bacterial burden on the implants was determined using a CFU assay40,41. To quantify living bacteria adherent to the implant within the biofilm, the removed implants were placed individually into 1.5-mL microtubes containing PBS (1 mL at 4C), vortexed for 15 s and sonicated for 5 min at 40 Hz in a water bath (Bransonic 5210; Branson Ultrasonics, Brookfield, CT, USA), followed by an additional 1 min of vortexing. The spread plate method was used to quantitatively evaluate the biofilm; the solution containing each bacterium from the biofilm was serially diluted 10-fold with PBS, followed by culturing on an agar plate at 37C for 24 h. MSSA was cultured on tryptic soy broth agar plates. The bacterial CFUs obtained from the implant were determined by counting the CFUs after culturing on plates overnight.

At the established endpoint (POD14), the femurs isolated from the rats were fixed in 10% neutralized formalin solution and dehydrated using an ethanol gradient (70%, 80%, 90%, and 100%). The fixed specimens were decalcified in 10% formic sodium citrate solution, embedded in paraffin, and sectioned in the coronal plane. The sections were stained with hematoxylin and eosin, and the slides were observed using an optical microscope (Biorevo BZ-9000; Keyence Corp., Osaka, Japan).

At the established endpoint (POD14), total RNA was extracted from the knee tissue of the rats (n = 6 rats per group). The mRNA expression of rCRAMP, TNF-, IL-6 and IL-1b was evaluated by quantitative PCR. All values were normalized to the level of the GAPDH gene, and relative gene expression levels were calculated using the 2Ct method42. Further details can be found in the Supplementary file (Supplementary Table S1).

Tissue sections were evaluated to determine the location of ADSCs following injection. To confirm the location of the injected ADSCs, they were labeled with the fluorescent dye DiI (Vybrant DiI Cell Labeling Solution; Life Technologies, Carlsbad, CA, USA) before injection. DiI binds to cellular thiols and has long-term stability, enabling the tracing of DiI-labeled transplanted cells in the host tissue. The concentration of ADSCs was adjusted to 5.0 105 cells/mL; DiI (5 L/mL) was dissolved in the cell culture media and incubated for 15 min at 37C in a 5% CO2 incubator for ADSCs labeling. The filtrate was centrifuged at 180g for 5 min at 25C and the supernatant was removed to separate the DiI from the filtrate. The ADSCs were centrifuged twice with Dulbeccos modified Eagle medium under the same conditions and the supernatant was removed. We used separate rats for this experiment (n = 3 rats per antibiotic group and DiI-labeled ADSCs with antibiotic group). On day 14 post-injection, a frozen section was prepared using Kawamotos film method in the sagittal plane43. For identification of tissues following DiI labeling, the gray-scale scale (16 bit) of the DiI-labeled section was used.

All continuous variables were assessed for normality using the ShapiroWilk test. Normally distributed data were expressed as the mean standard error. Data were analyzed using SPSS software (version 25.0; SPSS, Inc., Armonk, NY, USA). Multiple groups were compared using the Welch ANOVA followed by Tukey HSD or Games-Howell post-hoc test. For all analyses, results were considered statistically significant at p < 0.05.

The investigational protocol was approved by the Kanazawa University Advanced Science Research Centre (Approval Number: AP-194052), and all animals were treated in accordance with Kanazawa University Animal Experimentation Regulations. The study was carried out in compliance with the ARRIVE guidelines.

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Combined adipose-derived mesenchymal stem cell and antibiotic ... - Nature.com