Abstract

T lymphocytes are critical players in acute graft-versus-host disease (aGVHD).  PD1 expression on the T cell surface was identified to induce immune tolerance in a mouse GVHD model; in addition, PD1+TIM3+ double-positive T cells displayed more potent immunosuppression compared to PD1+ T cells. However, their clinical potential is greatly limited by their low cell number in peripheral blood (PB). We already introduced a novel method to obtain a high number of CD3+PD1+TIM3+ lymphocytes that culturing CD3+ cells isolated from G-CSF mobilized peripheral blood stem cells (CD3+G-PBSC) with human serum albumin (HSA). We also confirmed that cultured PD1+TIM3+ lymphocytes are the most potent subset of the CD3+ cells that inhibit T cell proliferation. In this study, we investigate the immunosuppressive effects of cultured lymphocytes after a 2-day culture with HSA (D2-CD3+G-PBSC) or after a 4-day culture with HSA (D4-CD3+G-PBSC). Also, we evaluate the treatment efficacy of D2-CD3+G-PBSC or D4-CD3+G-PBSC in the xenograft mouse aGVHD model. In the control group, 14% of the mice survived at 100 days. Mice that were treated with D2-CD3+G-PBSC and D4-CD3+G-PBSC demonstrated 100% and 71% survival rate at 100 days, respectively. Thus, Ex vivo HSA treatment of CD3+ G-PBSCs for 2 days shows promising therapeutic potential for the treating patients with aGVHD

Abstract

Adipose-derived stem cells (ASCs) are a cornerstone of regenerative medicine due to their multipotency, ease of isolation, and ability to differentiate into various cell types, including endothelial cells (ECs). ASCs can be harvested from different fat depots, such as subcutaneous, visceral, and perivascular adipose tissue, each exhibiting unique biological properties and differentiation potentials. These depot-specific differences influence their ability to differentiate into ECs and contribute to angiogenesis, the process of forming new blood vessels, which is critical for tissue repair and regeneration in conditions like ischemic diseases, chronic wounds, and tissue engineering. MicroRNAs (miRNAs), small non-coding RNAs that regulate gene expression, play a central role in directing ASC differentiation into ECs and modulating angiogenic processes. Specific miRNAs, such as miR-126, miR-145, miR-210, and miR-424, have been identified as key regulators of endothelial differentiation by targeting signaling pathways like VEGF, PI3K/Akt, and Notch. These miRNAs promote the expression of endothelial-specific markers, such as CD144, CD31 and von Willebrand factor, while enhancing EC functionality, including proliferation, migration, and tube formation. Interestingly, the miRNA expression profiles and angiogenic potential of ASCs vary depending on their fat depot origin, with subcutaneous ASCs often showing superior angiogenic capacity compared to visceral ASCs. Beyond direct differentiation, ASC-derived miRNAs also contribute to angiogenesis through paracrine signaling, influencing the surrounding microenvironment and supporting vascular repair. The dual role of miRNAs in ASC differentiation and angiogenesis highlights their therapeutic potential in cell-based therapies. By understanding the interplay between fat depot-specific ASCs, miRNAs, and angiogenesis, researchers aim to develop innovative strategies to enhance vascular regeneration, improve tissue perfusion, and achieve better clinical outcomes in patients with vascular-related disorders. The integration of depot-specific ASCs and miRNA-based therapies represents a transformative approach in the field of regenerative medicine.

Abstract

In recent years, mesenchymal stem cells (MSCs) derived from umbilical cord Wharton’s jelly (ucMSCs) have gained much attention in regenerative medicine. Multiple papers have described their high differentiation potential, as well as their important immunomodulatory effects. Umbilical cords (UC) offer an extensive source of ucMSCs for clinical applications, with the same benefits as other MSCs used in autologous cell therapies. In addition, they have the advantage that their procurement does not involve any risk, as UC are usually discarded after birth. Considering that wound healing after skin injury is a complex process and conventional treatments are not effective enough in several types of injuries that are widespread worldwide, we have developed a new therapy, especially for chronic venous ulcers (CVU), which consists on the allogeneic application of a specific ucMSC-derived cell line. We have characterized this cell line through numerous in vitro assays to advance the necessary knowledge for this type of cell therapy. Then, we carried out pre-clinical trials in mice to analyze graft acceptance after allogeneic cell transplantation. Based on the good results, we developed an equine ucMSC-derived cell line, to initiate the first clinical trials in equines. Our results showed that human and equine cell lines can be applied allogeneically for successful healing by creating a tolerogenic environment by expressing key immune checkpoints. In the murine pre-clinical trial, we observed that the cells reduced healing time by 50%. In the equine clinical trial, injection of equine ucMSCs into severe leg lesions improved the closure time and the quality of the regenerated tissues involved, without exuberant fibrous scar formation. All of the above leads us to conclude that both, human and equine cell lines, represent an important advance for the future cell therapies in regenerative medicine.