Extracellular matrix-mediated differentiation of human embryonic stem cells: differentiation to insulin-secreting beta cells

Union is strength: matrix elasticity and microenvironmental factors codetermine stem cell differentiation fate

Stem cells are an attractive cellular source for regenerative medicine and tissue engineering applications due to their multipotency. Although the elasticity of the extracellular matrix (ECM) has been shown to have crucial impacts in directing stem cell differentiation, it is not the only contributing factor. Many researchers have recently attempted to design microenvironments that mimic the stem cell niche with combinations of ECM elasticity and other cues, such as ECM physical properties, soluble biochemical factors and cell-cell interactions, thereby driving cells towards their preferred lineages. Here, we briefly discuss the effect of matrix elasticity on stem cell lineage specification and then summarize recent advances in the study of the combined effects of ECM elasticity and other cues on the differentiation of stem cells, focusing on two aspects: biophysical and biochemical factors. In the future, biomedical scientists will continue investigating the union strength of matrix elasticity and microenvironmental cues for manipulating stem cell fates.

Generation of functional human pancreatic β cells in vitro

The generation of insulin-producing pancreatic β cells from stem cells in vitro would provide an unprecedented cell source for drug discovery and cell transplantation therapy in diabetes. However, insulin-producing cells previously generated from human pluripotent stem cells (hPSC) lack many functional characteristics of bona fide β cells. Here, we report a scalable differentiation protocol that can generate hundreds of millions of glucose-responsive β cells from hPSC in vitro. These stem-cell-derived β cells (SC-β) express markers found in mature β cells, flux Ca(2+) in response to glucose, package insulin into secretory granules, and secrete quantities of insulin comparable to adult β cells in response to multiple sequential glucose challenges in vitro. Furthermore, these cells secrete human insulin into the serum of mice shortly after transplantation in a glucose-regulated manner, and transplantation of these cells ameliorates hyperglycemia in diabetic mice.

Functional maintenance of differentiated embryoid bodies in microfluidic systems: a platform for personalized medicine

Hormone replacement therapies have become important for treating diseases such as premature ovarian failure or menopausal complications. The clinical use of bioidentical hormones might significantly reduce some of the potential risks reportedly associated with the use of synthetic hormones. In the present study, we demonstrate the utility and advantage of a microfluidic chip culture system to enhance the development of personalized, on-demand, treatment modules using embryoid bodies (EBs). Functional EBs cultured on microfluidic chips represent a platform for personalized, patient-specific treatment cassettes that can be cryopreserved until required for treatment. We assessed the viability, differentiation, and functionality of EBs cultured and cryopreserved in this system. During extended microfluidic culture, estradiol, progesterone, testosterone, and anti-müllerian hormone levels were measured, and the expression of differentiated steroidogenic cells was confirmed by immunocytochemistry assay for the ovarian tissue markers anti-müllerian hormone receptor type II, follicle-stimulating hormone receptor, and inhibin β-A and the estrogen biosynthesis enzyme aromatase. Our studies showed that under microfluidic conditions, differentiated steroidogenic EBs continued to secrete estradiol and progesterone at physiologically relevant concentrations (30-120 pg/ml and 150-450 pg/ml, respectively) for up to 21 days. Collectively, we have demonstrated for the first time the feasibility of using a microfluidic chip system with continuous flow for the differentiation and extended culture of functional steroidogenic stem cell-derived EBs, the differentiation of EBs into cells expressing ovarian antigens in a microfluidic system, and the ability to cryopreserve this system with restoration of growth and functionality on thawing. These results present a platform for the development of a new therapeutic system for personalized medicine.

Stemistry: the control of stem cells in situ using chemistry

A new paradigm for drug research has emerged, namely the deliberate search for molecules able to selectively affect the proliferation, differentiation, and migration of adult stem cells within the tissues in which they exist. Recently, there has been significant interest in medicinal chemistry toward the discovery and design of low molecular weight molecules that affect stem cells and thus have novel therapeutic activity. We believe that a successful agent from such a discover program would have profound effects on the treatment of many long-term degenerative disorders. Among these conditions are examples such as cardiovascular decay, neurological disorders including Alzheimer's disease, and macular degeneration, all of which have significant unmet medical needs. This perspective will review evidence from the literature that indicates that discovery of such agents is achievable and represents a worthwhile pursuit for the skills of the medicinal chemist.

Controlled heterogeneous stem cell differentiation on a shape memory hydrogel surface

The success of stem cell therapies is highly dependent on the ability to control their programmed differentiation. So far, it is commonly believed that the differentiation behavior of stem cells is supposed to be identical when they are cultured on the same homogeneous platform. However, in this report, we show that this is not always true. By utilizing a double-ion-triggered shape memory effect, the pre-seeded hMSCs were controllably located in different growth positions. Here, we demonstrate for the first time that the differentiation behavior of hMSCs is highly sensitive to their growth position on a hydrogel scaffold. This work will not only enrich the mechanisms for controlling the differentiation of stem cells, but also offer a one-of-a-kind platform to achieve a heterogeneously differentiated stem cell-seeded hydrogel scaffold for complex biological applications.

The potential of cell-based therapy for diabetes and diabetes-related vascular complications

Cell therapy has enormous potential for the treatment of conditions of unmet medical need. Cell therapy may be applied to diabetes mellitus in the context of beta cell replacement or for the treatment of diabetic complications. A large number of cell types including hematopoietic stem cells, mesenchymal stem cells, umbilical cord blood, conditioned lymphocytes, mononuclear cells, or a combination of these cells have been shown to be safe and feasible for the treatment of patients with diabetes mellitus. The first part of this review article will focus on the current perspective of the role of embryonic stem cells and inducible pluripotent stem cells for beta cell replacement and the current clinical data on cell-based therapy for the restoration of normoglycemia. The second part of this review will highlight the therapeutic role of MSCs in islet cells cotransplantation and the management of diabetes related vascular complications.