Immunological properties of extraembryonic human mesenchymal stromal cells derived from gestational tissue

Heterogeneous functions of perinatal mesenchymal stromal cells require a preselection before their banking for clinical use

Perinatal sources of mesenchymal stromal cells (MSCs) have raised growing interest because they are readily and widely available with minimal ethical/legal issues and can easily be stored for allogeneic settings. In addition, perinatal tissues are known to be important in mediating the fetomaternal tolerance of pregnancy, which confer upon perinatal-MSCs (P-MSCs) a particular interest in immunomodulation. It has been recently shown that it is possible to deeply modify the secreted factor profiles of MSCs with different cytokine stimuli such as interferon gamma or tumor necrosis factor alpha to license MSCs for a better immunosuppresive potential. Therefore, we aimed to compare adult bone marrow-MSCs with MSCs from perinatal tissues (cord blood, umbilical cord, amnion, and chorion) on their in vitro immunological and stromacytic efficiencies under different priming conditions. Our results showed that P-MSCs had a potential to modulate the in vitro immune response and be useful for hematopoietic progenitor cell ex vivo expansion. However, we showed contrasted effects of cytokine priming embedded in an important between-donor variability. In conclusion, our study highlights the importance to elaborate predicitive in vitro tests to screen between-donor variability of perinatal tissues for banking allogeneic standardized MSCs.

Interactions between HLA-G and HLA-E in Physiological and Pathological Conditions

HLA-G and HLA-E are immunoregulatory molecules that belong to HLA-Ib family. The role of these molecules in the control of the immune response has been extensively analyzed, both in physiological and pathological conditions. We have here summarized data present in the literature regarding the interaction of these molecules in different settings. These data suggested that HLA-G and -E co-operate in physiological conditions (i.e., establishment of an immune tolerance at maternal/fetal interface during pregnancy), whereas their role in the course of tumors or autoimmune/inflammatory diseases may be different or even opposite. Future studies aimed at investigating the interaction between HLA-G and HLA-E will help to clarify mechanism(s) underlying the regulation of immune effector cells in health and disease.

In vitro generation of atrioventricular heart valve neoscaffolds

Tissue engineering of cardiovascular structures represents a novel approach to improve clinical strategies in heart valve disease treatment. The aim of this study was to engineer decellularized atrioventricular heart valve neoscaffolds with an intact ultrastructure and to reseed them with umbilical cord-derived endothelial cells under physiological conditions in a bioreactor environment. Mitral (n=38) and tricuspid (n=36) valves were harvested from 40 hearts of German Landrace swine from a selected abattoir. Decellularization of atrioventricular heart valves was achieved by a detergent-based cell extraction protocol. Evaluation of the decellularization method was conducted with light microscopy and quantitative analysis of collagen and elastin content. The presence of residual DNA within the decellularized atrioventricular heart valves was determined with spectrophotometric quantification. The described decellularization regime produced full removal of native cells while maintaining the mechanical stability and the quantitative composition of the atrioventricular heart valve neoscaffolds. The surface of the xenogeneic matrix could be successfully reseeded with in vitro-expanded human umbilical cord-derived endothelial cells under physiological flow conditions. After complete decellularization with the detergent-based protocol described here, physiological reseeding of the xenogeneic neoscaffolds resulted in the formation of a confluent layer of human umbilical cord-derived endothelial cells. These results warrant further research toward the generation of atrioventricular heart valve neoscaffolds on the basis of decellularized xenogeneic tissue.

Epithelial and Mesenchymal Stem Cells from the Umbilical Cord Lining Membrane

Intense scientific research over the past two decades has yielded much knowledge about embryonic stem cells, mesenchymal stem cells from bone marrow, as well as epithelial stem cells from the skin and cornea. However, the billions of dollars spent in this research have not overcome the fundamental difficulties intrinsic to these stem cell strains related to ethics (embryonic stem cells), as well as to technical issues such as accessibility, ease of cell selection and cultivation, and expansion/mass production, while maintaining consistency of cell stemness (all of the stem cell strains already mentioned). Overcoming these technical hurdles has made stem cell technology expensive and any potential translational products unaffordable for most patients. Commercialization efforts have been rendered unfeasible by this high cost. Advanced biomedical research is on the rise in Asia, and new innovations have started to overcome these challenges. The Nobel Prize-winning Japanese development of iPSCs has effectively introduced a possible replacement for embryonic stem cells. For non-embryonic stem cells, cord lining stem cells (CLSCs) have overcome the preexisting difficulties inherent to mesenchymal stem cells from the bone marrow as well as epithelial stem cells from the skin and cornea, offering a realistic, practical, and affordable alternative for tissue repair and regeneration. This novel CLSC technology was developed in Singapore in 2004 and has 22 international patents granted to date, including those from the US and UK. CLSCs are derived from the umbilical cord outer lining membrane (usually regarded as medical waste) and is therefore free from ethical dilemmas related to its collection. The large quantity of umbilical cord lining membrane that can be collected translates to billions of stem cells that can be grown in primary stem cell culture and therefore very rapid and inexpensive cell cultivation and expansion for clinical translational therapies. Both mesenchymal and epithelial stem cells can be isolated from the umbilical cord lining membrane, usefully regenerating not only mesenchymal tissue, such as bone, cartilage, and cardiac and striated muscle, but also epithelial tissue, such as skin, cornea, and liver. Both mesenchymal and epithelial CLSCs are immune privileged and resist rejection. Clinically, CLSCs have proved effective in the treatment of difficult-to-heal human wounds, such as diabetic ulcers, recalcitrant chronic wounds, and even persistent epithelial defects of the cornea. Heart and liver regeneration has been shown to be successful in animal studies and await human trials. CLSCs have also been shown to be an effective feeder layer for cord blood hematopoietic stem cells and, more recently, has been recognized as an abundant and high-quality source of cells for iPSC production. Banking of CLSCs by cord blood banks in both private and public settings is now available in many countries, so that individuals may have their personal stores of CLSCs for future translational applications for both themselves and their families. Cord lining stem cells are strongly positioned to be the future of cell therapy and regenerative medicine.

Umbilical cord-derived mesenchymal stem cells: Their advantages and potential clinical utility

Human umbilical cord (UC) is a promising source of mesenchymal stem cells (MSCs). Apart from their prominent advantages, such as a painless collection procedure and faster self-renewal, UC-MSCs have shown the ability to differentiate into three germ layers, to accumulate in damaged tissue or inflamed regions, to promote tissue repair, and to modulate immune response. There are diverse protocols and culture methods for the isolation of MSCs from the various compartments of UC, such as Wharton’s jelly, vein, arteries, UC lining and subamnion and perivascular regions. In this review, we give a brief introduction to various compartments of UC as a source of MSCs and emphasize the potential clinical utility of UC-MSCs for regenerative medicine and immunotherapy.

Umbilical cord mesenchymal stem cells: the new gold standard for mesenchymal stem cell-based therapies?

Due to their self-renewal capacity, multilineage differentiation potential, paracrine effects, and immunosuppressive properties, mesenchymal stromal cells (MSCs) are an attractive and promising tool for regenerative medicine. MSCs can be isolated from various tissues but despite their common immunophenotypic characteristics and functional properties, source-dependent differences in MSCs properties have recently emerged and lead to different clinical applications. Considered for a long time as a medical waste, umbilical cord appears these days as a promising source of MSCs. Several reports have shown that umbilical cord-derived MSCs are more primitive, proliferative, and immunosuppressive than their adult counterparts. In this review, we aim at synthesizing the differences between umbilical cord MSCs and MSCs from other sources (bone marrow, adipose tissue, periodontal ligament, dental pulp,…) with regard to their proliferation capacity, proteic and transcriptomic profiles, and their secretome involved in their regenerative, homing, and immunomodulatory capacities. Although umbilical cord MSCs are until now not particularly used as an MSC source in clinical practice, accumulating evidence shows that they may have a therapeutic advantage to treat several diseases, especially autoimmune and neurodegenerative diseases.