Transplantation of human amniotic epithelial cells repairs brachial plexus injury: pathological and biomechanical analyses

Prospect of Mesenchymal Stem Cells in Enhancing Nerve Regeneration in Brachial Plexus Injury in Animals: A Systematic Review

Objectives

Brachial plexus injuries (BPI), although rare, often results in significant morbidity. Stem cell was thought to be one of BPI treatment modalities because of their nerve-forming regeneration potential. Although there is a possibility for the use of mesenchymal stem cells as one of BPI treatment, it is still limited on animal studies. Therefore, this systematic review aimed to analyze the role of mesenchymal stem cells in nerve regeneration in animal models of brachial plexus injury.

Method

This study is a systematic review with PROSPERO registration number CRD4202128321. Literature searching was conducted using keywords experimental, animal, brachial plexus injury, mesenchymal stem cell implantation, clinical outcomes, electrophysiological outcomes, and histologic outcomes. Searches were performed in the PubMed, Scopus, and ScienceDirect databases. The risk of bias was assessed using SYRCLE's risk of bias tool for animal studies. The data obtained were described and in-depth analysis was performed.

Result

Four studies were included in this study involving 183 animals from different species those are rats and rabbits. There was an increase in muscle weight and shortened initial onset time of muscle contraction in the group treated with stem cells. Electrophysiological results showed that mesenchymal stem cells exhibited higher (Compound muscle action potential) CMAP amplitude and shorter CMAP latency than control but not better than autograft. Histological outcomes showed an increase in axon density, axon number, and the formation of connections between nerve cells and target muscles.

Conclusion

Mesenchymal stem cell implantation to animals with brachial plexus injury showed its ability to regenerate nerve cells as evidenced by clinical, electrophysiological, and histopathological results. However, this systematic study involved experimental animals from various species so that the results cannot be uniformed, and conclusion should be drawn cautiously.

Amniotic Epithelial Cells Accelerate Diabetic Wound Healing by Modulating Inflammation and Promoting Neovascularization

Human amniotic epithelial cells (hAECs) are nontumorigenic, highly abundant, and low immunogenic and possess multipotent differentiation ability, which make them become ideal alternative stem cell source for regenerative medicine. Previous studies have demonstrated the therapeutic potential of hAECs in many tissue repairs. However, the therapeutic effect of hAECs on diabetic wound healing is still unknown. In this study, we injected hAECs intradermally around the full-thickness excisional skin wounds of db/db mice and found that hAECs significantly accelerated diabetic wound healing and granulation tissue formation. To explore the underlying mechanisms, we measured inflammation and neovascularization in diabetic wounds. hAECs could modulate macrophage phenotype toward M2 macrophage, promote switch from proinflammatory status to prohealing status of wounds, and increase capillary density in diabetic wounds. Furthermore, we found that the hAEC-conditioned medium promoted macrophage polarization toward M2 phenotype and facilitated migration, proliferation, and tube formation of endothelial cells through in vitro experiments. Taken together, we first reported that hAECs could promote diabetic wound healing, at least partially, through paracrine effects to regulate inflammation and promote neovascularization.

SPION-mediated miR-141 promotes the differentiation of HuAESCs into dopaminergic neuron-like cells via suppressing lncRNA-HOTAIR

In this study, a bioinformatics analysis and luciferase reporter assay revealed that microRNA‐141 could silence the expression of lncRNA‐HOTAIR by binding to specific sites on lncRNA‐HOTAIR. We used superparamagnetic iron oxide nanoparticles (SPIONs) to mediate the high expression of microRNA‐141 (SPIONs@miR‐141) in human amniotic epithelial stem cells (HuAESCs), which was followed by the induction of the differentiation of HuAESCs into dopaminergic neuron‐like cells (iDNLCs). qPCR, western blot, immunofluorescence staining and HPLC all suggested that SPION‐mediated overexpression of miR‐141 could promote an increased expression of brain‐derived neurotrophic factor (BDNF), DAT and 5‐TH in HuAESC‐derived iDNLCs. The RIP and ChIP assay also showed that overexpression of miR‐141 could significantly inhibit the recruitment and binding of lncRNA‐HOTAIR to EZH2 on BDNF gene promoter. cDNA microarray analysis revealed that the expression levels of 190 genes were much higher in iDNLCs than in HuAESCs. Finally, a protein interaction network analysis and identification showed that in the iDNLC group with SPIONs@miR‐141, factors that interact with BDNF, such as FGF8, SHH, NTRK3 and CREB1, all showed significantly higher expression levels compared with those in the SPIONs@miR‐Mut. Therefore, this study confirmed that the highly efficient expression of microRNA‐141 mediated by SPIONs could improve the efficiency of HuAESCs differentiation into dopaminergic neuron‐like cells.

Amniotic Epithelial Cells: A New Tool to Combat Aging and Age-Related Diseases?

The number of elderly people is growing at an unprecedented rate and this increase of the aging population is expected to have a direct impact on the incidence of age-related diseases and healthcare-associated costs. Thus, it is imperative that new tools are developed to fight and slow age-related diseases. Regenerative medicine is a promising strategy for the maintenance of health and function late in life; however, stem cell-based therapies face several challenges including rejection and tumor transformation. As an alternative, the placenta offers an extraordinary source of fetal stem cells, including the amniotic epithelial cells (AECs), which retain some of the characteristics of embryonic stem cells, but show low immunogenicity, together with immunomodulatory and anti-inflammatory activities. Because of these characteristics, AECs have been widely utilized in regenerative medicine. This perspective highlights different mechanisms triggered by transplanted AECs that could be potentially useful for anti-aging therapies, which include: Graft and differentiation for tissue regeneration in age-related settings, anti-inflammatory behavior to combat “inflammaging,” anti-tumor activity, direct lifespan and healthspan extension properties, and possibly rejuvenation in a manner reminiscent of heterochronic parabiosis. Here, we critically discuss benefits and limitation of AECs-based therapies in age-related diseases.