The cell cycle as a brake for β-cell regeneration from embryonic stem cells

The efficiency of stem cell differentiation into functional beta cells for treating insulin-requiring diabetes: Recent advances and current challenges

In recent years, the potential of stem cells (SCs) to differentiate into various types of cells, including β-cells, has led to a significant boost in development. The efficiency of this differentiation process and the functionality of the cells post-transplantation are crucial factors for the success of stem cell therapy in diabetes. Herein, this article reviews the current advances and challenges faced by stem cell differentiation into functional β-cells for diabetes treatment. In vitro, researchers have sought to enhance the differentiation efficiency of functional β-cells by mimicking the normal pancreatic development process, using gene manipulation, pharmacological and culture conditions stimulation, three-dimensional (3D) and organoid culture, or sorting for functional β-cells based on mature islet cell markers. Furthermore, in vivo studies have also looked at suitable transplantation sites, the enhancement of the transplantation microenvironment, immune modulation, and vascular function reconstruction to improve the survival rate of functional β-cells, thereby enhancing the treatment of diabetes. Despite these advancements, developing stem cells to produce functional β-cells for efficacious diabetes treatment is a continuous research endeavor requiring significant multidisciplinary collaboration, for the stem-cell-derived beta cells to evolve into an effective cellular therapy.

Lessons from neonatal β-cell epigenomic for diabetes prevention and treatment

Pancreatic β-cell expansion and functional maturation during the birth-to-weaning period plays an essential role in the adaptation of plasma insulin levels to metabolic needs. These events are driven by epigenetic programs triggered by growth factors, hormones, and nutrients. These mechanisms operating in the neonatal period can be at least in part reactivated in adult life to increase the functional β-cell mass and face conditions of increased insulin demand such as obesity or pregnancy. In this review, we will highlight the importance of studying these signaling pathways and epigenetic programs to understand the causes of different forms of diabetes and to permit the design of novel therapeutic strategies to prevent and treat this metabolic disorder affecting hundreds of millions of people worldwide.

Acute effect of an amino acid mixture in the rat glycemic profile

Amino acid mixtures (AAM) are protein substitutes used for phenylketonuria treatment, but their metabolic effects have not been well characterized. The objective of this study was to compare the acute glycemic response to free amino acids (free AA) from AAM with the response to intact protein (iProtein). Male Wistar rats (n = 14) were administered by gavage a bolus of free AA (n = 7) or iProtein as albumin (n = 7) containing equivalent amounts of nitrogen. Blood glucose and insulin levels were measured at baseline and 15, 30, 60 and 120 minutes later, when gut GLP-1 content and pancreatic insulin, GLP-1 receptor and Ki67 expression were quantified at 120 minutes time point. After AAM, glucose area under the curve (free AA vs iProtein; P < 0.01), serum insulin levels at 120 minutes (free AA vs iProtein; P < 0.05), colon GLP-1 content (free AA vs iProtein; P < 0.01), pancreatic GLP-1 receptor (free AA vs iProtein; P < 0.01) and insulin expression (free AA vs iProtein; p < 0.01) were significantly lower as compared with iProtein. AAM increased Ki67 expression in pancreatic islets (free AA vs iProtein; P < 0.05). In conclusion, this study demonstrated that acute response to AAM differs from iProtein and is characterized by a lower glucose excursion, along with a decrease in gut GLP-1 and pancreatic GLP-1 receptor and insulin. This data suggests the modulation of glycemia by free AA is mediated by the incretin axis.

Targeting RNA helicase DDX3 in stem cell maintenance and teratoma formation

DDX3 is an RNA helicase that has antiapoptotic properties, and promotes proliferation and transformation. Besides the role of DDX3 in transformed cells, there is evidence to indicate that DDX3 expression is at its highest levels during early embryonic development and is also expressed in germ cells of adults. Even though there is a distinct pattern of DDX3 expression during embryonic development and in adults, very little is known regarding its role in embryonic stem cells and pluripotency. In this work, we examined the relationship between DDX3 and human embryonic stem cells and its differentiated lineages. DDX3 expression was analyzed by immunohistochemistry in human embryonic stem cells and embryonal carcinoma cells. From the data obtained, it was evident that DDX3 was overexpressed in undifferentiated stem cells compared to differentiated cells. Moreover, when DDX3 expression was abrogated in multiple stem cells, proliferation was decreased, but differentiation was facilitated. Importantly, this resulted in reduced potency to induce teratoma formation. Taken together, these findings indicate a distinct role for DDX3 in stem cell maintenance.