The concept of synthesizing small-scale human organs in lab dishes has matured from pure science fiction to legitimate bioscientific reality in recent years. However, the usefulness of organoids as a research tool for studying the digestive system quickly ran into a roadblock, due to the fact that these in-demand tissues remain difficult to create.

Organoids are stem cell-derived three-dimensional tissue cultures that are designed to exhibit detailed characteristics of organs or act as model organs to produce a specific cell type in laboratory conditions. However, when growing organoids, the yield from each batch of starting material can vary massively and can even fail to produce any viable organoids at all. This of course results in severe delays in their production and utilization in pre-clinical experiments that test the efficacy and safety of drugs.

In a recently published paper from Stem Cell Reports, researchers from Cincinnati childrens (OH, USA) have developed a new practice that overcomes the organoid production hurdle. This novel procedure is already being utilized within the medical facility to boost organoid studies. However, because the materials utilized can be frozen and thawed while still producing high-quality organoids, this discovery allows for the shipment of starter materials to other labs anywhere in the world, foreseeably leading to a dramatic increase in the utilization of human gastrointestinal organoids in medical research.

This method can make organoids a more accessible tool, explains the first author Amy Pitstick, manager of the Pluripotent Stem Cell Facility at Cincinnati Childrens. We show that the aggregation approach consistently produces high yields and we have proven that precursor cells can be thawed from cryogenic storage to produce organoids of the small intestine.

Using this approach will make it possible for many research labs to use organoids in their experiments without the time and expense of learning how to grow induced pluripotent stem cells (iPSCs), states corresponding author Chris Mayhew, director of the Pluripotent Stem Cell Facility. The ability to freeze the precursor cells also will allow labs to easily make organoids without having to start each new experiment with complicated and highly variable iPSC differentiation.

Generally, organoid creation begins with the collection of skin or blood cells, which are then transformed in the lab to become induced pluripotent stem cells. To create intestinal organoids, highly skilled lab professionals produce a flat layer of organ precursor cells known as the mid-hindgut endoderm.

Under the correct conditions, early-stage organoids, termed spheroids, autonomously develop into a three-dimensional ball of cells. These are then collected and placed into a growth medium, which supplies the required signals for the cells to develop into the specialized cell types of a human organ.

However, the quantity of spheroids produced in this manner has been unpredictable. The Cincinnati Childrens researchers discovered that they could harvest the unused precursor cell layer and employ a centrifuge to transport cells into hundreds of tiny wells housed on small plastic plates. This causes the creation of 3D cell aggregates, which may then be collected and utilized to produce organoids.

The experiment described in the research paper demonstrates that the spheroids created in this manner had no discernible differences from those that formed naturally. The scientists then stored samples of the progenitor cells in freezers. These cells generated viable spheroids after being frozen and aggregated.

The paper goes on to verify that these spheroids can be consistently grown into mature organoids, which can simulate organ function. In the case of this research, the mature organoids went on to mimic the function of the small intestine, large intestine and the antrum, the portion of the stomach that links to the intestine.

Although this development is a welcome and promising advance in organoid fabrication, years of research will be required to create organoids large enough and complex enough to be utilized as replacement tissue in transplant surgery. However, having access to a large number of readily manufactured organoids offers up numerous possibilities for medical study.

More labs will be able to create patient-specific organoids in order to evaluate drugcombination therapiesfor precision treatment of complex or rare disease states that necessitate personalized care. Scientists also conducting basic research to understand more about the genetic factors and molecular pathways at play in digestive tract diseases will be able to incorporate organoids in their experiments by procuring frozen spheroid precursors.

In his current effort to generate transplantable intestinal tissues, Michael Helmrath, Director of Clinical Translation for the Center for Stem Cell & Organoid Medicine (CuSTOM) at Cincinnati Childrens, has already begun employing materials made from this new method.

This is a great step forward for the field on many fronts, Helmrath says. To be able to reduce the complexity of the process and provide higher yields is beneficial to our work. And to be able to translate the methods to other labs will help move regenerative medicine forward.

Source: https://linkinghub.elsevier.com/retrieve/pii/S2213671122003599

Read more:
New milestone organoid synthesis will boost disease and drug development research - RegMedNet