This story illustrates how I feel about much of the experimental work that I do and what I see others do in academic and clinical labs. There is an existing infrastructure sometimes far below the cutting edge of science and technology that “works” well enough to test your hypothesis and publish the paper you need for a better job where you can make others deal with the same inconvenient infrastructure. There are many logical reasons for sticking with what works, but, as in the case of the new roundabout, there is a point where superior technology becomes economical.

The tools used to develop therapies for diabetes, in all its forms, also need an upgrade. As with most biomedical research, two complementary platforms are generally used. On the one hand, cultured cells are an inexpensive resource for early-stage high-throughput studies. On the other hand, animals provide a complex, physiological environment to more accurately predict what is happening in the human body. However, the limitations of existing animal and cell culture models are not addressed by simply using both. Microfluidic platforms have natural advantages over both traditional cell culture and animal models. There are of course limitations here as well and these pain points are opportunities for commercial development. The advantages and current limitations of using microfluidic models of human tissues and organs are listed below to encourage their commercial development and adoption for diabetes research.

The Advantages We Need to Exploit

• Organ Modularity and Isolation: When experimenting on animals, it is often challenging to deduce the molecular mechanisms of disease traits due to the complexity of interactions between different organs, tissues, and cells. One can delete or overexpress a gene to demonstrate the respective necessity and sufficiency of that gene for the trait, but in which organ is the expression of that gene important? Tissue-specific genetic manipulation helps address this issue, but it remains challenging for diseases like diabetes where multiple genes operating in multiple organs contribute to pathogenesis. Moreover, many disease-associated genes and cell types are vital (i.e. lethal when deleted) necessitating alternative approaches. Engineered organ models can be connected to build systems such as the “body-on-a-chip” platforms discussed in a previous blog post¹.Microfluidics aid in the logistical difficulty of combining multiple cell types, tissues, and organs as a synthetic vasculature to promote nutrient delivery and waste removal. Relevant organ, tissue, or cellular components can be added as needed and connected in a manner that enables sampling of the inputs and outputs for each component of the system.

• Controlled Human Genetic Background: Gene networks that are most relevant to diabetes such as those involved in immunity and metabolism are also the most evolutionarily distinct between mice, the predominant animal model for diabetes², and humans³. In this regard, an experimental system with human cells is advantageous over mice. Multiple tissues derived from a single pluripotent stem cell line can be used for a completely isogenic model if desired. Alternatively, different genetic backgrounds can be combined to simulate transplantation, chimerism, or other experimental conditions. For example, combining five different organ models made from mutant and control cells from the same stem cell line is simpler than developing constructs for five separate genes each with distinct tissue-specific promoters. In addition, similar to the above point about vital genes, it is also conceivable that a tissue of interest lacks an established tissue-specific gene promoter.

• Data Quality, Automation and Cost Reduction: The temporal resolution of experimental data is often limited by the minimum sample volumes of well-based assays and the capacity of the human user. Microfluidics is naturally amenable to automated sample collection, reagent mixing, and measurement acquisition, reducing user error and manual effort. Microfluidics also have the inherent potential for cost efficiency due to the small amounts of reagents required⁴. Huge cost savings are possible if the supporting instrumentation is made to be simple and self-contained. By minimizing the time, error, effort, and expense of data collection, microfluidics simultaneously enable superior temporal resolution and data quality.

The Limitations We Need to Address

• Not quite in vivo…yet: Although genetic divergence favours a platform with a human genetic background for diabetes research, conventional cell culture falls woefully short of recapitulating important tissue-specific hallmarks of diabetes as well as the systemic nature of the disease. This is the primary criticism and limitation of cell culture and thus a major opportunity for microfluidic organ models. In my opinion, the key moving forward for diabetes research is less about making perfect and interconnected replicas of every organ in the body (which very well could take forever), and more about meeting a set of design criteria that cover the key features and phenotypes underlying specific hypotheses to be tested. The latter is achievable in our lifetime and can close the gap between patients and existing preclinical models.

• Not quite user-friendly …yet: A broadly accessible platform cannot become mainstream without industry’s help and probably its leadership, too. Academic labs simply cannot manufacture enough products with the necessary quality control for all the parties that stand to benefit by using it. Industry involvement will also be needed to achieve the right balance of standardization and flexibility. Utility for a broad range of applications will help the broad adoption of the technology. Finally, product designs need to integrate controls for tissue culture and functional readouts that allow operation without extensive training or expertise.

Conclusion

Diabetes research presents an exciting market opportunity for the development of microfluidic organ models and systems. The powerful advantages afforded by microfluidics are much needed to complement (and perhaps eventually replace) traditional cell culture and animal testing. If designed appropriately for non-expert users and with the right biological questions in mind, these platforms will be adopted and more importantly will help pave the new and improved road to a cure.

References

<sup>1. Organ On Chips: Questions To Address Before They Can Move Into Mainstream Applications. URL: https://ufluidix.com/circle/organ-on-chips-questions-to-address-before-they-can-move-into-mainstream-applications/

2. King A. The use of animal models in diabetes research. British Journal of Pharmacology. 166(3) (2012).

3. Yue F, Cheng Y, Breschi A, et al. A comparative encyclopedia of DNA elements in the mouse genome. Nature. 515(7527) (2014).

4. https://www.fluigent.com/microfluidic-expertise/what-is-microfluidic/microfluidic-definitions-and-advantages/</sup>

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Benjamin D. Pope

Ben Pope works with a group of scientists and engineers who aim to cure diabetes. His current research leverages cellular engineering and genomics to elucidate the molecular bases of human nutrition. Originally trained in molecular biology, he identified DNA elements that define structural and functional chromosome units by both chromosome engineering in embryonic stem cells and computational analysis of genomic datasets. He has since cross-trained in bioengineering and developed a microfluidic chip for continuous sensing of insulin secreted by ex vivo human islets described in a previous blog post.

• https://scholar.harvard.edu/pope

The post Developing Diabetes Therapies with Microfluidic Organ Models appeared first on The MicroFluidic Circle.

Financial potential is being matched medical potential, as microenvironments play a role in new findings about stem cell treatment that may speed patients’ recovery from chemotherapy and radiation. And microfluidics advances have also led to a new tool for diabetes research.

Bone marrow stem cells produce the body’s blood and immune cells, but chemotherapy and radiation suppress that production, and it can take weeks or months for the blood and immune systems to recover. Results of a recent study by UCLA Broad Stem Cell Research Center scientists showed how a newly developed drug compound might hasten the blood system’s recovery after radiation and chemotherapy in mice. Some of the heretofore unknown capacity of microenvironments were critical to this type of investigation.

“The potency of this compound in animal models was very high,” said study co-author Dr. John Chute. “It accelerated the recovery of blood stem cells, white blood cells and other components of the blood system necessary for survival. If found to be safe in humans, it could lessen infections and allow people to be discharged from the hospital earlier.”

Looking at both mouse — and human stem cells (in dishes) — growth factors were observed to promote the recruitment of stem cells from degraded bone marrow, which fueled proliferation and reconstitution. “We’re very excited about the potential medical applications of these findings,” said Chute.

The new compound enabled the blood system to recover sooner from cancer treatments in mice because it was able to stop the molecular process that slows blood stem cell regeneration. “The new compound lifts molecular ‘brakes’ that normally slow the regeneration of blood stem cells,” according to the team.

The new compound speeded up the regeneration of both mouse and human blood stem cells after exposure to radiation. The bloodstream’s own regenerative capacity seemed to power up healing. Angiogenesis, the formation of new blood cells, is controlled by chemical signals, yet many of the mechanisms by which blood cell regeneration uses bone marrow have been unknown. The study highlights the process by which growth factors recruit stem cells from the bone marrow microenvironment. Advances detailing bone marrow’s microenvironments are a significant contribution.

Microfluidic devices can be monitored and imaged using fluorescent markers for tracking, and microenvironments needed to be precisely controlled for this investigation.

Among the mice that received high doses of radiation, almost all that were given the compound survived; more than half of those that did not receive the compound died. Mice that received chemotherapy but no compound had low levels of white blood cells and neutrophils — which fight bacteria — after two weeks; in mice that were treated, white blood cell counts recovered to normal levels within two weeks. The researchers are now refining the process, in preparation for human trials.

Microfluidics research also has another new arrow in its quiver, in the form of a new tool for diabetes research, developed by a team based at the Harvard Stem Cell Institute. The device improves aspects of studying diabetes, including upgrading the screening process prior to transplantation of insulin-producing cells into a patient.

The team noted that although microfluidic devices have been used to address research limitations in the past, previous adoption has been hampered by “incompatibility of most device materials with large-scale manufacturing. We designed and built a thermoplastic, microfluidic-based Islet-on-a-Chip compatible with commercial fabrication methods, that automates islet loading, stimulation, and insulin sensing.”

The design of their “Islet-on-a-Chip” is based on the human pancreas, where islets process non-stop, incoming information about glucose levels, and adjust insulin production accordingly. The new, automated, miniature device gives results in real-time, which can speed up clinical decision-making.

In addition to diabetes research, the device may prove useful in other areas. Its core technology can be modified to sense an array of microfluidic systems. Because it can detect cell secretions continuously, it can be employed to investigate how cells communicate using protein signals, throughout the body.

“It was exciting to see our lab’s method for measuring islet function taken forward from individual cells to much bigger groups of cells, and incorporated into a device that can be used widely in the community,” said co-author Dr. Michael Roper. “Now, we have a device that integrates glucose delivery, islet positioning and capture, reagent mixing, and insulin detection, and requires far fewer reagents. So labs can use it to do more experiments at the same cost, using a much shorter and easier process.”

Scalable, easier, shorter, and cost-contained. That says it all.

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Kathy Jean Schultz

Kathy Jean Schultz is a freelance medical science writer who focuses on medical innovations. She earned a Master’s Degree in Research Methodology from Hofstra University, and a Master’s Degree in Psychology from Long Island University. She is a member of the National Association of Science Writers, and the Association of Health Care Journalists. Her articles about organoids include "Would you trust a 3-D printed mini organ to test your drugs?" and "Stem cells not only slow disease, they come with their own safety test".

• http://kathyjeanschultz.pressfolios.com/

The post Industry Predictions of Microfluidics Commercialization are Buoyed by Recent Advances in Diabetes and Cancer Research appeared first on The MicroFluidic Circle.

Recent findings by a team of engineering and medical scientists at Stanford University shed new light on how cell components move around and self-renew. Part of the study’s focus was on the link between microtubules and self-organization.

Microtubules, hollow tubes about 25 nm in diameter, are critical for maintaining cell shape and movements. The study analyzed what role microtubules have in maintenance, and found that microtubules are continuously losing and gaining molecules. Understanding the mechanics of how microtubules move around and contribute to regeneration helps to light affordable paths to wound healing in humans and animals.

Cells are known to self-organize at the direction of particular protein structures, via recognized regulators of the organization. However, the Stanford team observed that some cells self-organized in the absence of their known regulators. An interaction between microtubules and other molecules on the membrane surface was the reason.

This observation raised questions about what role microtubules play in the regeneration when other elements of the system are paralyzed. The researchers described how microtubules seemed to be involved in some minimal requirements for cellular self-organization. Identifying this process opens the door to greater understanding of cell renewal.

Clarifying the precise functions of microfluidics has paved the way to viable organoids, on which assessments can be done without having to conduct tests on an entire organism. For example, the University of British Columbia researchers recently were able to architect human vascular organoids that were nurtured to duplicate diabetic blood vessels, and can be used as test models.

The UBC scientists were able to grow human blood vessels as organoids in a lab, for the first time. This spawns investigation of treatments for vascular diseases by highlighting how changes to blood vessels occur. Such changes are a major cause of death among diabetics.

An illustration of vascular organoids, lab-made human blood vessels, based on original data. Credit: IMBA

“Being able to build human blood vessels as organoids from stem cells is a game changer,” said the study’s senior author Josef Penninger. “Every single organ in our body is linked with the circulatory system. This could potentially allow researchers to unravel the causes and treatments for a variety of vascular diseases, from Alzheimer’s disease, cardiovascular diseases, wound healing problems, stroke, cancer and, of course, diabetes.”

Many diabetic symptoms are the result of changes in blood vessels that result in impaired oxygen supply of tissues, and impaired circulation. Not a lot has been known about vascular changes arising from diabetes. This creation of human blood-vessel organoids is a significant step toward tipping the scales from unknowns to knowns.

Determining how to cultivate three-dimensional human blood-vessel organoids in a lab dish is indeed a huge step toward unveiling blood-vessel change mechanisms.

These “vascular organoids” when transplanted into mice, developed into functional human blood vessels, including capillaries and arteries. So not only was it possible to engineer blood-vessel organoids from human stem cells in a dish, but they also grew a functional human vascular system in another species.

The organoids resemble human capillaries to a great extent, even on a molecular level, and can be used to study blood vessel diseases directly on human tissue. The researchers described how organoids can be used to study the lack of oxygen and nutrient delivery to blood vessels that occurs in diabetic patients, causing complications including kidney failure, heart attacks, strokes, blindness, and the peripheral artery disease that leads to amputations.

They were surprised to find the vascular organoids showed expansion of the basement membrane, which is exactly what causes the oxygen-and-nutrient depletion in humans. The damage to the vascular organoids precisely mirrored what is seen in diabetic patients.

Using the vascular organoids for testing, they found that no currently-prescribed anti-diabetic medications had positive effects on these blood vessel defects. But they did find an enzyme inhibitor that prevented thickening of the basement membrane.

The researchers noted that the findings could allow them to identify underlying causes of vascular disease, and to potentially develop and test new treatments for the world’s estimated 420 million people with diabetes.

That many patients should theoretically translate into significant Research and Development endeavors.

Enjoyed this article? Don’t forget to share.

Kathy Jean Schultz

Kathy Jean Schultz is a freelance medical science writer who focuses on medical innovations. She earned a Master’s Degree in Research Methodology from Hofstra University, and a Master’s Degree in Psychology from Long Island University. She is a member of the National Association of Science Writers, and the Association of Health Care Journalists. Her articles about organoids include "Would you trust a 3-D printed mini organ to test your drugs?" and "Stem cells not only slow disease, they come with their own safety test".

• http://kathyjeanschultz.pressfolios.com/

The post Being Able to Build Human Blood Vessels as Organoids from Stem Cells is a Game Changer appeared first on The MicroFluidic Circle.