Purification technologies for induced pluripotent stem cell therapies – Nature.com

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Purification technologies for induced pluripotent stem cell therapies - Nature.com

Finishing the odyssey to a stem cell cure for type 1 diabetes – Nature.com

A recent clinical study by Pipeleers and colleagues has brought the possibility of a stem-cell based cure one step closer1. This perspective will summarize the major hurdles that have been overcome to deliver cell-based improvements in glucose control and highlight the key issues that stand between this important proof-of-concept clinical study and a durable cure for the majority of patients living with T1D.

The autoimmune destruction of pancreatic cells creates a lifelong dependence on insulin to control blood sugar levels in individuals with type 1 diabetes (T1D). Over time, poorly managed T1D causes microvascular and macrovascular complications that significantly impact quality of life2. Unfortunately, intensive glucose lowering therapy to reduce these long-term complications of hyperglycemia is accompanied by an increased risk of hypoglycemic events3. Technological solutions aiming to replace cell function with an artificial pancreas can improve glucose control by integrating continuous glucose monitoring with automated insulin delivery4. However, these systems have not yet matched the exquisite blood glucose control provided by human islets5, and T1D patients remain burdened with the ongoing management and expense of a chronic disease.

Therapeutic approaches aimed at restoring a functional -cell mass could eventually eliminate the need for exogenous insulin. Indeed, transplant of cadaveric islets into immunosuppressed T1D recipients has shown that excellent glucose control can be achieved6, while simultaneously reducing hypoglycemic risk7. The benefits of islet transplant to individual T1D islet recipients should not be minimized, however, the limited supply of donor tissue constrains the potential impact of this strategy, which is still only available to clinical trial participants in many countries including the USA. In contrast, human pluripotent stem cells (hPSCs)8,9 could theoretically be expanded and differentiated to restore a functional -cell mass in all eligible patients with T1D if they can be shielded from autoimmune attack.

Initially, a major goal was to optimize stem cell differentiation protocols to produce glucose-responsive cells from hPSCs. The first major success was guided by developmental studies from diverse model organisms10, in which step-wise modulation of key developmental signals produced cells capable of expressing insulin11, albeit at low levels and in a largely constitutive manner. Nevertheless, this was a remarkable demonstration that hPSCs have the potential to be used for cell-replacement therapy. Extensive empirical optimization and an appreciation of the functional importance of islet structure led to -cells with improved function12,13. We note, the in vitro generation and characterization of stem-cell derived islets has been recently reviewed14. However, the observation that in vitro differentiated hPSC-derived -cells exhibit immature physiological responses15, like many other hPSC-derived cell products16, led to consideration of alternative strategies. A surprisingly effective approach has involved halting in vitro differentiation once pancreatic fate is established at the multipotent pancreatic progenitor (PP) stage and allowing -cell differentiation and functional maturation to be guided by endogenous cues post-transplant17. An added benefit of this approach is that PP differentiation is amenable to the large-scale expansion and Good Manufacturing Practice (GMP) production and quality control required for clinical application18. Interestingly, further differentiation and enrichment of hormone-positive islet-like cells prior to transplant does not reduce the in vivo maturation time19.

Now that a suitable cell-source is available, preventing graft rejection is one of the greatest challenges facing hPSC-based therapies. The autoimmune nature of T1D poses a challenge for cell-based therapies since the immune system is poised to destroy newly transplanted material, even if it is derived from the patients own stem cells. As seen with cadaveric transplants, systemic immunosuppression can protect and maintain unmatched donor cells in a functional state6. Furthermore, clinical transplants have shown that ~10,000 islet equivalents/kg provide a functional -cell mass that can eliminate the need for exogenous insulin20, setting a clear goal for therapeutic effect. Unfortunately, this blunt force approach trades dependence on insulin for continuous immunosuppression, which brings increased risks of infections, certain cancers and regimen-specific toxicities21.

Encapsulating transplants in biocompatible materials that prevent immune infiltration, while permitting sufficient diffusion of nutrients and waste products to support -cell health, has been pursued to eliminate the need for systemic immunosuppression. Despite the demonstration over 40 years ago that microencapsulation is sufficient to preserve islet function for several weeks in an animal model without immune suppression22, maintaining a functional -cell mass within cell-impermeable materials remains a major challenge. Microencapsulated islets (single islets or small clusters) can disperse into the recipient tissue where they benefit from a large contact area with the host. However, the impermeable barrier prevents direct contact with blood vessels, which produce a basement membrane that is likely essential for optimal -cell function23. These problems have been even more pronounced in cell-impermeable macroencapsulation devices, where elaborate designs such as intravascular hollow fibers are used to increase exposure to the bloodstream24. However, despite the theoretical advantages of close contact with the blood stream, the serious risk of blood clots associated with vascular prostheses has impeded clinical translation of intravascular devices25. The strengths and weaknesses of additional islet encapsulation technologies have been recently reviewed26.

Because cell impermeable materials necessarily prevent direct contact between -cells and the endothelium, some groups have gone a different direction with cell-permeable devices, including Viacyte with the VC-02 device. Although the exact configuration of the VC-02 remains proprietary, key features that appear to have contributed to clinical success are a perforated encapsulation membrane that is encased in another layer of perforated non-woven fabric27. The VC-02 device loaded with hPSC-derived Pancreatic Endoderm Cells (PECs) that are partially differentiated to the PP stage has been coined the PEC-Direct (Fig. 1).

Partially differentiated hPSC-derived PECs were loaded into devices that mature under the protection of systemic immunosuppression in T1D patients. The perforated design facilitates the infiltration of endothelial cells, while the external non-woven fabric restricts fibrotic foreign body responses. After maturation, functional cells comprised 3% of the total cell mass. MO macrophage, T T cell, NK Natural Killer cell.

While most clinical experience is associated with transplant of cadaveric islets to the portal vein in the liver, additional subcutaneous, omental, and intramuscular sites have been extensively studied in preclinical models28. These sites may pose additional challenges for islet survival since the limited clinical data available suggests that unencapsulated extrahepatic transplants do not perform well29. However, encapsulated hPSC-derived PPs transplanted subcutaneously differentiate into tissue that contains functional glucose responsive cells within 4-6 months in animal models30,31. Building on this experience, two parallel first-in-human studies aimed to optimize the cell dose and perforation configuration of PEC-Direct subcutaneous implants in small numbers of T1D recipients (n=1732; n=1533) demonstrated that C-peptide, a marker produced by insulin-secreting cells, could be newly detected in some individuals at 6 months post-transplant and could persist until 24 months. A subset of patients achieved >30 pM C-peptide after meal stimulation (6/24, note some individuals were analyzed in both studies), a level that is associated with reduced T1D complications34. However, none of the individuals reached the 200 pM threshold associated with improved metabolic control34 or the 1000 pM level associated with insulin independence in cadaveric islet recipients35. For reference, postprandial C-peptide levels range from 1000-3000 pM in healthy individuals36. Importantly, the observed insulin production could be directly attributed to the VC-02 devices, and not the recovery of the recipients own cell function, since removal of the explants eliminated the improvements in C-peptide levels in two patients where this was carefully explored33. While comparison of transplanted PEC cells with cadaveric islets in terms of islet equivalents can only be approximated, these pilots delivered at most one-half the transplant volume required for insulin independence. Since the recovered devices contained mostly glucagon+ cells (16%) and only a small fraction of insulin+ cells (3%) it is not surprising that the transplants were not sufficient to improve secondary measures of glycemia. Regardless, these first-in-human studies demonstrated the overall safety of the approach in high risk (hypoglycemia unaware) patients with all serious adverse events attributed to the immunosuppressive regimen or surgical procedure, suggesting that maximizing transplant size and -cell composition were going to be crucial for clinical impact.

In an interim report of 1-year outcomes, Keymeulen et al., now provide evidence that hPSC transplants are on the cusp of providing benefit to many patients. Using an adaptive trial design, the transplant volume was increased 2-3 fold and all devices used the perforation pattern and density associated with the best outcomes in previous trials32,33 The transplant recipients were selected using similar criteria to the previous trials, requiring stable T1D (>5 years), a high risk for hypoglycemic complications (Clarke score 4), and meal-stimulated C-peptide levels 30 pM prior to transplant. With the increased dose and optimized device configuration, 3/10 recipients produced 100 pM postprandial C-peptide from 6-months post-transplant and one surpassed the 200 pM threshold associated with metabolic significance. Excitingly, this individual achieved improved time spent in the target blood sugar range (by continuous glucose monitoring), a clinically meaningful measure of function.

Now that hPSC-derived cells have been shown to produce metabolically significant amounts of insulin in a T1D patient, there is a path to match and potentially exceed the outcomes observed with cadaveric transplants. Assuming a linear relationship between -cell mass and insulin secretion, it appears that a further ~10-fold increase in functional -cell mass would be sufficient to achieve insulin-independence (>1000 pM C-peptide) in some patients and a metabolic benefit (>200 pM C-peptide) in most recipients. Unfortunately, simply further increasing the transplant size would likely increase surgical complications. Consistent across the clinical trials, recovered PEC-Direct devices contained large acellular regions filled with extracellular matrix. This material permanently occupies space that could be better utilized as cells currently comprise at most ~3% of the total volume within a device1. Although histological analysis of the PEC-Direct devices retrieved from the non-responders was not available in the interim report, further insight into the fate of transplanted PPs and the composition of infiltrating cells in failed grafts will help focus future efforts. Interestingly, in samples from two responders, the less functional graft was already dominated by infiltrating recipient cells at 3 months post-transplant and the cell mass was negligible at 9 months despite having a larger total cell volume1. Human islets are composed of ~50% cells that are interspersed with other endocrine cell types and aligned to the vasculature37. Thus, if the majority of the device volume were filled with islet-like structures, there should be a sufficient functional cell mass for most patients.

Recapitulating embryonic pancreatic development in vitro has produced PPs that clearly have the potential to complete differentiation into functional cells in a process that takes 4-6 months post-transplant. Additional clues from developmental biology indicate that there are stage-specific interactions between endogenous endocrine precursors and the vasculature that influence pancreatic differentiation. Initially, endothelial cells induce the differentiation of endocrine cells38, which then signal back to increase the density of the local vascular network39 and deposition of a vascular basement membrane that promotes cell function23. Thus, cells participate in the construction of a specialized niche through interactions with the vasculature that are essential for subsequent cell maturation. While the perforated design of the PEC-Direct device allows infiltration of endothelial cells, the growth of this vascular network takes time and is competing with recipient fibroblasts which are only partially blocked by the outer non-woven fabric layer (Fig. 1), suggesting that there are limitations to mechanical control of these processes. The strengths and weaknesses of the PEC-Direct device compared to other cell-based therapies are summarized in Table 1. Here, we highlight recent advances that could help maximize the yield of vascularized cells and in the best-case scenario provide an immune privileged niche that would eliminate the need for systemic immunosuppression (Fig. 2).

Immunomodulatory materials and cells could be used to create an immune privileged niche for transplanted PECs and further discourage fibroblast infiltration. cell numbers could potentially be increased by improving the microenvironment and converting other pancreatic cell types to the cell fate. MO macrophage, T T cell, NK Natural Killer cell. Treg Regulatory T cell, M2 M2 macrophage, CXCL12 CXCL12 chemokine.

The materials in the PEC-Direct device, particularly the outermost non-woven fabric layer, suppress a full-blown foreign body response associated with the recruitment of macrophages and fibroblasts to the interface with recipient tissues27. Limiting residual fibroblast infiltration1 might be most important in the acute post-transplant period, as they likely interfere with PP differentiation and the establishment of the intra-device vascular network. The precise composition of the perforated VC-02 encapsulation membrane remains proprietary. However, if it is composed of alginate or similar material, then biomodulatory factors could be directly integrated into the encapsulation membrane40. Notably, incorporation of the CXCL12 chemokine was recently shown to protect microencapsulated xenogeneic islets in a non-human primate model41. The primary mechanism of acute islet protection is associated with repulsion of islet-reactive effector T cells42. However, CXCL12 has multiple immune modulatory roles43, and protected islets also show reduced macrophage and fibroblast surface infiltration and collagen deposition40,41. These studies suggest that incorporating chemokine(s) such as CXCL12 into the encapsulation membrane, or potentially adding an additional biomodulatory layer, could improve the microenvironment within the device. Additional advances in biomaterials functionalized with diverse immunomodulatory molecules have been recently reviewed in the context of islet transplantation44.

Giving the vasculature a head start could be a complementary way to limit the opportunities for intra-device fibrosis. Instead of relying exclusively on the recipients vasculature, the addition of ready-made microvessels isolated from adipose tissue to hPSC-derived PPs improved early graft survival and reduced the time required for cell differentiation to less than 10 weeks in mouse T1D models45. Harvesting recipient microvessels would add additional complexity to a clinical transplant program but a proof-concept pilot study using healthy donor microvessels could be informative. Ideally, microvessel-equivalents would also be produced from hPSCs46, although scale up under GMP conditions as was done for PPs18 would also be needed.

Improving the intradevice microenvironment might increase not only the mature pancreatic cell volume within a device but potentially also the proportion of cells. In the small number of recovered grafts that have been analyzed histologically, cells comprise at most ~3% of the total cell volume1,33,34. In contrast, preclinical studies with similar device-encapsulated PPs have produced grafts with up to 16% cells by transplanting into a preformed pouch at the surgical site47. Presumably, the 5 weeks between pouch formation and device engraftment allowed for vascularization of the transplant site and resolution of acute inflammatory responses. Importantly, these data indicate that partially differentiated PPs are capable of producing significantly more cells within an optimized microenvironment. Beyond improving the host environment, an attractive source of additional cells is from transdifferentiated cells, which are invariably the most abundant pancreatic cell type identified after in vivo maturation of PPs1,47. While paracrine signals from cells are important for optimal cell function48, these intraislet interactions are unlikely to be compromised by the transdifferentiation of excess cells that are currently produced in superphysiological proportions. Furthermore, reducing cell content in the graft could have metabolic benefits as there is growing evidence that hyperglucagonemia interferes with cell function49. cells have an innate ability to transdifferentiate, although it is only triggered by near complete cell destruction50,51. Overexpression of the key cell transcription factors PDX1 and MAFA in adult cells produces -like cells with the ability to sense glucose and secrete insulin52,53, although these cells retain aspects of their previous cell identity. To avoid perturbing differentiation to the PP stage in vitro, implementing directed transdifferentiation in hPSC-derived transplants will require engineered stem cells with the ability to induce cell factors specifically in mature endocrine cells54. A further 2-3 fold increase of the cell mass observed in preclinical studies via transdifferentiation would produce structures with very similar cellular composition to endogenous human islets37.

The ultimate goal of a hPSC-based therapy for T1D is to provide long-term cell function without the need for systemic immunosuppression. Cotransplantation of microgels containing individual immunomodulatory factors such as PD-L155 or FasL56 can have profound effects on graft survival in immunocompetent hosts. For example, FasL presenting microbeads combined with only two weeks of rapamycin monotherapy supported graft function for over six months and induced Treg-dependent local tolerance without systemic effects on the immune system in an allogeneic mouse model56. Similar effects were seen in non-human primates57, although the long-term viability of the grafts was not evaluated.

In addition to achieving allogeneic graft tolerance, hPSC-derived cells must contend with the dysregulated autoimmune response in T1D. Excitingly, it now appears possible to fully cloak hPSCs and their differentiated progeny by overexpressing a cocktail of 8 immunomodulatory factors that includes PD-L1 and FASL58. Together, these factors disrupt antigen presentation, T-cell and NK cell attack, and innate inflammatory responses. By activating a proliferation-dependent kill switch59, cloaked cells could be maintained in a dormant state within an immunocompetent host. Furthermore, these cloaked cells protected their neighbors, including allogeneic islets and xenogeneic hPSCs. While PPs could potentially be generated directly from cloaked hPSCs, the overexpression of 8 genes might impact cell function long-term. An elegant strategy to address all the key issues discussed here would be to generate cloaked endothelial cells for cotransplantation with PPs that are genetically primed for to cell transdifferentiation.

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Finishing the odyssey to a stem cell cure for type 1 diabetes - Nature.com

Astellas and Graduate School of Medicine / Faculty of Medicine, Osaka University Enter into Research Collaboration to Develop Pluripotent Stem…

- Collaborative Research on Innovative Cartilage Organoid Cell Therapy for Intervertebral Disc Degenerative Disease using Astellas' Universal Donor Cell Technology -

TOKYOand OSAKA, Japan, July 22, 2024 /PRNewswire/ -- Astellas Pharma Inc. (TSE: 4503,President and CEO: Naoki Okamura,"Astellas") and Graduate School of Medicine / Faculty of Medicine, Osaka University (President: Shojiro Nishio"Osaka University") today announced that Astellas Institute for Regenerative Medicine (a wholly owned subsidiary of Astellas, "AIRM"), Universal Cells (a wholly owned subsidiary of Astellas) and Osaka University have entered into a research collaboration to develop innovative pluripotent stemcell*1-derived cartilage organoid cell therapy for the treatment of intervertebral disc degenerative disease*2.

Universal Cells holds the rights to Universal Donor Cell (UDC) technology to create cell therapy products from pluripotent stem cells that have reduced risk of immune rejection by genetically modifying Human Leukocyte Antigen (HLA) using gene editing technology.

Under the terms of the agreement, the three parties aim to combine the cartilage tissue creation protocol established by Professor Noriyuki Tsumaki of (Graduate School of Frontier Biosciences / Premium Research Institute for Human Metaverse Medicine) the Department of Tissue Biochemistry and Molecular Biology, Graduate School of Medicine, Osaka University, a leading researcher in cartilage diseases, Universal Cells' UDC technology, and AIRM's exceptional R&D expertise in cell therapy, and jointly create an innovative cell therapy for intervertebral disc degenerative disease.

Yoshitsugu Shitaka, Ph.D., Chief Scientific Officer (CScO) of Astellas"Astellas is committed to achieving our VISION of being "on the forefront of healthcarechange, turning innovative science into VALUE for patients". We hope to provide our cutting-edge UDC technology to academia and startups globally, and deliver next-generation cell therapies to patients. This partnership is an important step in the open innovation using UDC technology."

Professor Noriyuki Tsumaki, M.D., Ph.D., (Graduate School of Frontier Biosciences / Premium Research Institute for Human Metaverse Medicine) Department of Tissue Biochemistry and Molecular Biology, Graduate School of Medicine, Osaka University"We believe that our cartilage-like tissue has the potential to regenerate intervertebral discs. We hope that combining our research with Astellas' UDC technology and R&D cell therapy system will accelerate and realize the development of regenerative therapies to treat intervertebral disc degenerative disease."

*1 Pluripotent stem cell: Cells that possess the ability to proliferate almost indefinitely and differentiate into any cell that makes up the organism. Ex. embryonic stem cells (ES cells) and induced pluripotent stem cells (iPS cells). *2 Intervertebral disc degenerative disease: A type of degenerative spinal disease. The intervertebral discs, which are cartilaginous tissues, play a crucial role as cushions between each bone of the spine by containing a significant amount of water. This helps maintain flexible movement of the back. However, when these discs degenerate, they lose water, resulting in the failure of their cushioning function, which can lead to lower back pain.

About AstellasAstellas Pharma Inc. is a pharmaceutical company conducting business in more than 70 countries around the world. We are promoting the Focus Area Approach that is designed to identify opportunities for the continuous creation of new drugs to address diseases with high unmet medical needs by focusing on Biology and Modality. Furthermore, we are also looking beyond our foundational Rx focus to create Rx+ healthcare solutions that combine our expertise and knowledge with cutting-edge technology in different fields of external partners. Through these efforts, Astellas stands on the forefront of healthcare change to turn innovative science into VALUE for patients. For more information, please visit our website at https://www.astellas.com/en.

Cautionary Notes(Astellas)In this press release, statements made with respect to current plans, estimates, strategies and beliefs and other statements that are not historical facts are forward-looking statements about the future performance of Astellas. These statements are based on management's current assumptions and beliefs in light of the information currently available to it and involve known and unknown risks and uncertainties. A number of factors could cause actual results to differ materially from those discussed in the forward-looking statements. Such factors include, but are not limited to: (i) changes in general economic conditions and in laws and regulations, relating to pharmaceutical markets, (ii) currency exchange rate fluctuations, (iii) delays in new product launches, (iv) the inability of Astellas to market existing and new products effectively, (v) the inability of Astellas to continue to effectively research and develop products accepted by customers in highly competitive markets, and (vi) infringements of Astellas' intellectual property rights by third parties. Information about pharmaceutical products (including products currently in development) which is included in this press release is not intended to constitute an advertisement or medical advice.

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Astellas and Graduate School of Medicine / Faculty of Medicine, Osaka University Enter into Research Collaboration to Develop Pluripotent Stem...

‘We can’t answer these questions’: Neuroscientist Kenneth Kosik on whether lab-grown brains will achieve consciousness – Livescience.com

Brain organoids are 3D, lab-grown models designed to mimic the human brain. Scientists normally grow them from stem cells, coaxing them into forming a brain-like structure. In the past decade, they have become increasingly sophisticated and can now replicate multiple types of brain cells, which can communicate with one another.

This has led some scientists to question whether brain organoids could ever achieve consciousness. Kenneth Kosik, a neuroscientist at the University of California, Santa Barbara, recently explored that possibility in a perspective article. Live Science spoke with Kosik about how brain organoids are made, how similar they are to human brains and why he believes that brain organoid consciousness is not likely anytime soon.

Related: In a 1st, 'minibrains' grown from fetal brain tissue

EC: What are brain organoids, and how do scientists make them?

Kenneth Kosik: A brain organoid is made from stem cells. You can take any person and convert their, say, skin fibroblasts into stem cells, and then differentiate them into neurons. It's what stem cells are all about stem cells are called "pluripotent" because they can make any cell in the body.

We spent a fair amount of time before organoid technology came along, taking human-induced pluripotent stem cells and inducing them in a two-dimensional array to look at neuronal differentiation.

So that takes us halfway there. But it only gets us as far as two dimensions. And then the big insight, which came from Yoshiki Sasai in Japan and Madeline Lancaster, was to take these neurons that were beginning to differentiate cells relatively early in development and put them in a drop of what's called Matrigel a gel that can be either a liquid or a solid depending on the temperature.

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So the cells are in this drop, and then the magic happens. Instead of growing in two dimensions, they start to grow in three dimensions. It absolutely fascinates me that when biology begins to explore the third dimension, a very novel biology emerges. Certainly, in two dimensions, these neurons that were growing could achieve a very wide diversity of cell types, but they did not achieve any kind of interesting anatomy.

Once they're growing in three dimensions, they start to form relationships to each other, kinds of structure and anatomy, that has a very loose resemblance to the brain. And I really emphasize the word "loose," because there are people that use a misnomer for brain organoids and call them "minibrains." They're not brains at all. They are organoids meaning like the brain.

A question we're keenly interested in, and many labs are, is that if organoids are like the brain, to what degree do they resemble the brain and to what degree do they differ? And they differ from the brain a lot, so you have to be very careful about interpretations of organoids. Not everybody thinks that organoids are going to be informative for neuroscience because what we find in an organoid may be over-interpretation. But on the other hand, [it] is forming a three-dimensional structure that has some degree of lamination [formation of layers of cells within tissue], it has these rosettes in which, from the center of the rosette, you can progressively see cells becoming more mature as development proceeds, which is very similar to what happens in the brain.

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EC: Are there any brain organoids that accurately capture the whole brain yet?

KK: There is no organoid that captures the whole brain. There are approaches that attempt to capture more of the brain than, say, just the one part that maybe we and other labs are working on. These are called "assembloids." [Scientists] take stem cells and differentiate them down a pathway that may make a little more ventral [front part of the] brain, or a little more dorsal [back part of the] brain, and they put them together, they fuse them, so that you get more comprehensive fusion a wider representation, I should say, of brain anatomy.

There are other ways of making organoids that are a little more indiscriminate. They're not directing the stem cells towards dorsal and ventral, they are putting them all together. That's a lot of what we do. Those were the techniques that were originated by Lancaster. And in that case, it's my opinion that when you do it that way, you get a broader representation of cell types. That's what you gain, but you sacrifice anatomical accuracy because when you make an assembloid, the anatomy is not great. But when you do it without differentiating toward dorsal and ventral and you put it all together, the anatomy becomes even more problematic.

EC: As you alluded to, these organoids are similar to human brains, but there's some key physiological differences. Can you explain those?

KK: So, one similarity right away is that you see a lot of spiking going on.

(Editor's note: Kosik is referring to the fact that, when an organoid is hooked up to electrodes, this triggers electrical spikes, or signals, transmitted between neurons.)

It's quite remarkable, and underlying this is the notion, which is probably what intrigues me the most, that all of this activity is spontaneous: it just arises based on the assembly of the neurons.

And now we can look at the relationships of those spikes. When you do that, you can ask the question, well, if I see neuron A firing, what's the likelihood that I'll see neuron B firing? I'm going to look at the binary relationships among all of them and I'm doing it with the filter that when neuron A fires I'm only going to look at when another neuron fires within 5 milliseconds. Why 5 milliseconds? Because that's about the time in which it takes for transmission to occur across the synapse. (Editor's note: A synapse is the gap between two neurons.)

And when we do that, you can see that they form a network. You connect A and B, and then you connect C and D, and then A and C. You can see that the neurons are talking to each other and this arises spontaneously.

That is one example of the way in which an organoid does something that will spontaneously resemble what happens in the brain.

The way I look at an organoid, it is a vehicle that has the capacity to encode experience and information if that experience were available to it but it's not. It has no eyes, ears, nose or mouth nothing's coming in. But the insight here is that the organoid can set up spontaneous organization of its neurons so that it has the capacity to encode information, when and if it becomes available. That's just a hypothesis.

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EC: Do you think that brain organoids will ever achieve consciousness?

KK: So that's where things get a little mysterious. I think that those kinds of questions are predicated on this term that people have a lot of trouble defining: consciousness.

[Based on currently fashionable theories of consciousness] I would say, "No, it doesn't even come close."

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EC: You spoke about the fact that organoids have shown some capacity to encode information, but they don't have the experience to do this in the first place. What would happen if, hypothetically, a human brain organoid was transplanted into an animal? Could it then achieve consciousness?

KK: Let's break that down. Before it is transplanted into an animal, some people would say the animal already has consciousness and some people would say [it does] not. So, right away, we get into this difficulty about where in the animal kingdom does consciousness begin? So, let's reframe the question. If you then took an animal, which may or may not have some degree of consciousness, and you transplant in a human organoid, would you confer consciousness on that animal or would you enhance consciousness, or would you even get something that resembled human consciousness in the animal? I don't know the answer to any of those questions.

We can do these hybrids now so it's a good question. But the evaluation of consciousness now, because of all the problems as to what consciousness is, is still going to be an open question.

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EC: Do we have an idea of rough timescales , is consciousness something that could happen in the near future, after, say, a certain number of years, or is it still really uncertain at this point?

KK: Technology is moving very fast. One place where we may begin to push the boundary is in the so-called cyborgs, or organoid interfaces. That would be one direction that could be interesting. Maybe a little bit toward consciousness, but even more so toward developing the implementation of human abilities in one of these synthetic systems.

EC: Can you think of any obvious benefits and drawbacks of these organoids being able to achieve consciousness?

KK: We know so little about neuropsychiatric conditions. Neuropsychiatric drugs are developed without understanding any deep physiology. All of that could be done, I think, with organoids. I think as disease models, it could be very, very useful [for them to achieve consciousness].

The dream state that I have is to develop them as computational systems because, right now, to do the kinds of very expensive computations that are required for ChatGPT and many of these large language models, these take hundreds of millions of dollars to develop. They require a server farm of energy to keep them going. We're really just running out of computer power. Yet, the brain does a lot of this stuff on 20 watts. So, a big interest for me is, "Can organoids, if not solve, contribute to the huge demands that we're making on the energy system by tapping into the highly efficient way in which the brain, and presumably the organoid, can handle information?"

Editor's note: This interview has been edited and condensed.

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'We can't answer these questions': Neuroscientist Kenneth Kosik on whether lab-grown brains will achieve consciousness - Livescience.com