In vitro differentiation of human umbilical cord blood mesenchymal stem cells into functioning hepatocytes

Optimization of human umbilical cord blood-derived mesenchymal stem cell isolation and culture methods in serum- and xeno-free conditions

BACKGROUND

Although umbilical cord blood (UCB) is identified as a source of mesenchymal stem cells (MSCs) with various advantages, the success in cell isolation is volatile. Therefore, it is necessary to optimize methods of cord blood-derived MSC (UCB-MSC) isolation and culture. In this study, we evaluated the efficiency of UCB-MSC isolation and expansion using different commercially available serum- and xeno-free media and investigated the capacity of autologous serum and plasma as a supplement to support cell proliferation. Additionally, we defined the presence of multilineage-differentiating stress-enduring (Muse) cells in the UCB-MSC population. Functions of UCB-MSC in in vitro angiogenesis processes and anti-cancer were also verified.

METHODS

Mononuclear cells were isolated using density gradient separation and cultured in four commercial media kits, as well as four surface coating solutions. UCB-MSCs were characterized and tested on tube formation assay, and co-cultured with SK-MEL cells in a transwell system.

RESULTS

The results showed that only StemMACS™ MSC Expansion Media is more appropriate to isolate and culture UCB-MSCs. The cells exhibited a high cell proliferation rate, CFU forming capability, MSC surface marker expression, trilineage differentiate potential, and chromosome stability. In addition, the culture conditions with autologous serum coating and autologous plasma supplement enhanced cell growth and colony forming. This cell population contained Muse cells at rate of 0.3%. Moreover, UCB-MSCs could induce the tube formation of human umbilical vein endothelial cells and inhibit more than 50% of SK-MEL cell growth.

CONCLUSIONS

UCB-MSCs could be high-yield isolated and expanded under serum- and xeno-free conditions by using the StemMACS™ MSC Expansion Media kit. Autologous serum coating and plasma supplement enhanced cell proliferation. These UCB-MSCs had effected the tube formation process and an anti-cancer impact.

Different approaches for transformation of mesenchymal stem cells into hepatocyte-like cells

Due to the prominent role of the liver in the body and detoxification, its functionality can be affected in an irreversible manner by diseases. This phenomenon renders the liver to stop working, leading to morbidity and mortality. Therefore, liver transplantation is the only way to tackle this issue.In order to compensate for the lack of adequate healthy liver tissue for transplantation, therapeutic approaches such as hepatocyte transplantation have been proposed as an alternative. Recognizing the fact that mesenchymal stem cells are adult stem cells with the capacity to differentiate into several cell types, different methods have been invented to produce hepatocyte-like cells from mesenchymal stem cells. They can be divided into three main categories, such as addition of cytokines and growth factors, genetic modifications, and adjustment of microenvironment as well as physical parameters.In this review, we attempted to introduce diverse efficient methods for differentiating mesenchymal stem cells and their capability for transformation into hepatocyte-like cells.

Generation of insulin-producing hepatocyte-like cells from human Wharton's jelly mesenchymal stem cells as an alternative source of islet cells

Islet cell transplantation, as a treatment of type 1 diabetes, has a lot of complexity such as allograft rejections and an insufficient number of donors. The liver can be used as a replacement for endogenous insulin production. Hepatocytes can inherently respond to glucose levels and secrete proteins. Utilization of mesenchymal stem cells for curing diabetes represents a major focus of recent investigations. As a new choice for transplantation, we have proposed glucose-regulated insulin-producing hepatocyte-like cells, which produce insulin dependent on glucose levels. We have transfected human Wharton's jelly mesenchymal stem cells with the special construct, which included homology arms and glucose-responsive elements upstream of the minimum liver-type pyruvate kinase promoter-directed insulin gene. Then, we have differentiated these transfected cells to hepatocyte-like cells by using serial exposure of different inducing material and exogenous growth factors. Immunofluorescence analyses have demonstrated the expression of albumin, cytokeratin-18, Hep-Par1, α-fetoprotein, and insulin. The expression of hepatocyte marker genes in the differentiated cells was confirmed by reverse-transcription polymerase chain reaction. Interestingly, flow cytometry results showed that approximately 60% of the insulin-producing hepatocyte-like cells were simultaneously cytochrome P450 3A4 (CYP3A4) and insulin positive. CYP3A4 is a significant enzyme found in mature liver tissue. This confirmed that the differentiation and the transfection procedures were done correctly. They were functionally active by releasing insulin in response to elevated glucose concentrations in vitro. These applicable cells could be used in the liver for cell therapy of diabetes.