Stem cells and vascular regenerative medicine: A mini review

Construction of a Silk Fibroin/Polyethylene Glycol Double Network Hydrogel with Co-Culture of HUVECs and UCMSCs for a Functional Vascular Network

The success of complex tissue and internal organ reconstruction relies principally on the fabrication of a 3D vascular network, which guarantees the delivery of oxygen and nutrients in addition to the disposal of waste. In this study, a rapidly forming cell-encapsulated double network (DN) hydrogel is constructed by an ultrasonically activated silk fibroin network and bioorthogonal-mediated polyethylene glycol network. This DN hydrogel can be solidified within 10 s, and its mechanical property gradually increases to ∼20 kPa after 30 min. This work also demonstrates that coencapsulation of human umbilical vein endothelial cells (HUVECs) and umbilical cord-derived mesenchymal stem cells (UCMSCs) into the DN hydrogel can facilitate the formation of more mature vessels and complete the capillary network in comparison with the hydrogels encapsulated with a single cell type both in vitro and in vivo. Taking together, the DN hydrogel, combined with coencapsulation of HUVECs and UCMSCs, represents a strategy for the construction of a functional vascular network.

Harnessing Stem Cell Potential for the Treatment of Erectile Function in Men with Diabetes Mellitus: From Preclinical/Clinical Perspectives to Penile Tissue Engineering

Background::

According to the World Health Organization, more than 150 million people are diabetic, and this number will increase twofold by the year 2025. Diabetes-related complications affect all body organ systems, including the penis. Diabetes-induced Erectile Dysfunction (ED) is caused by neuropathy of the penile nerves and vasculopathy involving the smooth muscle and endothelium of the corpus cavernosum.

Objective::

This study aims to present an overview of Stem Cell (SC) research in diabetic animal models of ED, focusing on the function, signaling, and niches that have a prominent role in the regeneration of cavernosal cells and penile tissues. We highlight common erectile pathologies caused by diabetes and review relevant preclinical trials. We also discuss paracrine mechanisms of various SC therapies involved in the repair of endothelial cells and cavernous nerves in these diabetic models.

Method::

A PubMed search was performed, with dates ranging from inception until Mar 31, 2019.

Results::

This review provides a comprehensive evaluation of the various strategies that have been investigated for improving SC delivery methods, through preclinical literature and published clinical trials regarding ED in men with diabetes. Various cell-type applications have benefited erectile function in diabetic models of ED.

Conclusion::

This review examines the progress and remaining challenges in diabetes-related SC research regarding ED. Moving forward, it is only with a combined effort of basic biology and translational work that the potential of SC-based therapies in diabetes in ED can be realized.

Evaluation of human mesenchymal stem cell senescence, differentiation and secretion behavior cultured on polycarbonate cell culture inserts

Polycarbonate (PC) substrate is well suited for culturing human mesenchymal stem cells (MSCs) with high proliferation rate, low cell apoptosis rate and negligible cytotoxic effects. However, little is known about the influence of PC on MSC activity including senescence, differentiation and secretion. In this study, the PC cell culture insert was applied for human MSC culture and was compared with polystyrene (PS) and standard tissue culture plate (TCP). The results showed that MSCs were able to adhere on PC surface, exhibiting a spindle-shaped morphology. The size and distribution of focal adhesions of MSCs were similar on PC and TCP. The senescence level of MSCs on PC was comparable to that on TCP, but was significantly lower than that on PS. MSCs on PC were capable of self-renewal and differentiation into multiple cell lineages, including osteogenic and adipogenic lineages. MSCs cultured on PC secreted a higher level inflammatory cytokines and pro-angiogenic factors including FGF2 and VEGF. Conclusively, PC represents a promising cell culture material for human MSCs.

Modulation of the mesenchymal stem cell migration capacity via preconditioning with topographic microstructure

Controlling mesenchymal stem cells (MSCs) behavior is necessary to fully exploit their therapeutic potential. Various approaches are employed to effectively influence the migration capacity of MSCs. Here, topographic microstructures with different microscale roughness were created on polystyrene (PS) culture vessel surfaces as a feasible physical preconditioning strategy to modulate MSC migration. By analyzing trajectories of cells migrating after reseeding, we demonstrated that the mobilization velocity of human adipose derived mesenchymal stem cells (hADSCs) could be promoted by and persisted after brief preconditioning with the appropriate microtopography. Moreover, the elevated activation levels of focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) in hADSCs were also observed during and after the preconditioning process. These findings underline the potential enhancement of in vivo therapeutic efficacy in regenerative medicine via transplantation of topographic microstructure preconditioned stem cells.

Leukocyte-reduced platelet-rich plasma stimulates the in vitro proliferation of adipose-tissue derived mesenchymal stem cells depending on PDGF signaling

BACKGROUND

Platelet-rich Plasma (PRP) is suggested as xenoprotein-free cell-culture medium replacement for animal-derived supplements.

OBJECTIVE

The aim of this study was to investigate PRP-triggered signaling in adipose derived mesenchymal stem cells (ASCs).

METHODS

PRP was obtained from 4 male patients. We incubated ASCs in α-MEM with different Platelet derived growth factor (PDGF) subtypes or 10% or 20% pooled PRP or 20% fetal calf serum (FCS) prior to determination of the S-phase fraction (SPF). To investigate the influence of PDGF signaling on ASCs, PDGF receptor β inhibitor was added, and protein expression of ASCs was measured.

RESULTS

ASCs exposed to 20% PRP, PDGF-AB and - BB demonstrated significant higher SPF in comparison to PDGF-AA and 20% FCS after 48 hours (all P < 0.05). PDGF receptor β inhibition diminished the PRP-induced SPF increase of ASCs significantly after 48 hours (P < 0.01). ASCs with PDGF receptor β inhibition showed significant higher PDGF receptor β and significant lower c-MYC expression compared to untreated cells in presence of 20% PRP after 48 hours (both P < 0.05).

CONCLUSIONS

The proliferation promoting effect of PRP on ASCs is mediated by PDGF signaling and is associated with c-MYC overexpression.

Effects of different concentrations of Platelet-rich Plasma and Platelet-Poor Plasma on vitality and differentiation of autologous Adipose tissue-derived stem cells

BACKGROUND

Autologous fat grafts and adipose-derived stem cells (ASCs) can be used to treat soft tissue defects. However, the results are inconsistent and sometimes comprise tissue resorption and necrosis. This might be due to insufficient vascularization. Platelet-rich plasma (PRP) is a source of concentrated autologous platelets. The growth factors and cytokines released by platelets can facilitate angiogenesis. The simultaneous use of PRP might improve the regeneration potential of fat grafts. The optimal ratio has yet to be elucidated. A byproduct of PRP preparation is platelet-poor plasma (PPP).

OBJECTIVE

In this study we investigated the influence of different concentrations of PRP on the vitality and differentiation of ASCs.

METHODS

We processed whole blood with the Arthrex Angel centrifuge and isolated ASCs from the same donor. We tested the effects of different PRP and PPP concentrations on the vitality using resazurin assays and the differentiation of ASCs using oil-red staining.

RESULTS

Both cell vitality and adipogenic differentiation increase to a concentration of 10% to 20% PRP. With a PRP concentration of 30% cell vitality and differentiation decrease.

CONCLUSIONS

Both PRP and PPP can be used to expand ASCs without xenogeneic additives in cell culture. A PRP concentration above 20% has inhibitory effects.