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Background Mesenchymal stem cells (MSCs) exert positive effects in chronic wounds. However, critical parameters, such as the most effective administration routes, remain unclear. Accordingly, the purpose of this study was to compare the effects of topical and systemic transplantation MSCs on diabetic ischemic wound healing and explored the underlying mechanisms. Method A diabetic ischemic wound model was created on the dorsal foot of type 2 diabetes mellitus (T2DM) rat. Bone marrow-derived mesenchymal stem cells (BM-MSCs) were administered via two routes: topical injection and intravenous (IV) infusion. Wound healing outcomes and blood glucose level were assessed dynamically. Meanwhile, blood flow recovery was evaluated in ischemic gastrocnemius muscles. The homing and transdifferentiation of mKate2-labeled BM-MSCs were assessed by fluorescence imaging and immunohistochemistry (IHC) analysis. Result Both topical and systemic treatments had a positive effect on the diabetic ischemic wound showing a significant reduction in wound area at day 14. Histological results showed an increase in the length of epithelial edges, collagen content, microvessel density in the wound bed, and a higher expression of vascular endothelial growth factor (VEGF). Meanwhile, systemic administration can ameliorate hyperglycemia and improve the blood perfusion of the ischemic hindlimb. BM-MSCs administered systemically were found distributed in wounded tissue and transdifferentiated into endothelial cells. Furthermore, BM-MSCs stimulated angiogenesis at wound sites by downregulating phosphatase and tensin homolog (PTEN) and activation of AKT signaling pathway. Conclusions The results demonstrated that both transplantation delivery method (topical and systemic) of BM-MSCs accelerated wound healing remarkably under pathological conditions. Nevertheless, systemic administration has the potential to ameliorate hyperglycemia and repair the damaged tissue.

Background Recent evidence suggests that angiotensin II (Ang II) plays a role in cutaneous wound healing. Mesenchymal stem cells (MSCs) are known as a rich source of cells that re‐establish healed skin. However, the potential impact of Ang II on MSC differentiation into keratinocytes is still unknown. Objective The present study was conducted to explore the effect of Ang II on the differentiation of bone marrow‐derived MSCs (BM‐MSCs) into keratinocytes. Methods Bone marrow‐derived MSCs were isolated from rat bone marrow and cultured. The expression of Ang II type 1 (AT1) and type 2 (AT2) receptors was examined by immunofluorescence staining. The differentiation of BM‐MSCs into keratinocytes was investigated by flow cytometry or/and histological observation. Results The BM‐MSCs constitutively expressed both AT1 and AT2 receptors. The differentiation of BM‐MSCs into keratinocytes was successfully induced. Interestingly, incubation of BM‐MSCs with Ang II further promoted the differentiation of BM‐MSCs into keratinocyte, which was abolished by pretreament with losartan, an AT1 receptor antagonist, but not by PD123319, an AT2 receptor antagonist. Moreover, the p38 mitogen‐activated protein kinase (MAPK) inhibitor SB203580, the c‐Jun N‐terminal kinase (JNK) inhibitor SP600125 and the Janus‐activated kinase (JAK)2 inhibitor AG490 suppressed Ang II‐induced differentiation of BM‐MSCs into keratinocytes. The phosphoinositide‐3 kinase (PI3K) inhibitor wortmannin and MEK1/2 inhibitor U0126 had no effect on BM‐MSC differentiation into keratinocytes. Conclusions Our data demonstrated for the first time that Ang II plays a promotive role in the differentiation of BM‐MSC into keratinocytes through the AT1 receptor, and that the p38 MAPK, JNK and JAK2 signalling pathways are involved in this process.

Adipose-derived stem cells (ADSCs) are mesenchymal stem cells that are often used in regenerative medicine. Maintaining ADSC viability is important, as this optimizes the curative effects of cell therapy. However, the optimal conditions for cell viability preservation remain unknown. The present study aimed to acquire a better protocol for ADSC storage by comparing the effects of various solutions and temperatures for ADSC preservation, in order to suggest the most effective methods of short-term ADSC preservation for clinical use. ADSCs from passage 2 were suspended in solutions comprising 0.9% NaCl, 10% human serum (HS) or 10% platelet-rich plasma (PRP). Suspended cells were maintained at 4°C or room temperature (~26°C) for 2, 4 and 6 h. The differentiation capacity, apoptosis and proliferation of ADSCs were determined by oil red O/alizarin red S staining, flow cytometry, and a cell counting kit-8 cell proliferation assay, respectively. In addition, reverse transcription-quantitative polymerase chain reaction and western blot analysis was performed. The results revealed that proliferation of ADSCs decreased with time. The optimal time for ADSC use was ~2 h, and 4 h was determined to be the latest time that ADSCs should be used. The 10% HS group had the highest survival rate, followed by the 10% PRP group; these two groups had higher survival rates than the 0.9% NaCl group (P<0.05). HS and PRP at 4°C enhanced the ADSC proliferation rate (P<0.05), although the difference between these two groups was insignificant (P>0.05). In conclusion, the optimal time to use ADSCs was <2 h, and should not exceed 4 h. It was recommended that, for the transportation and short-term storage of ADSCs during clinical use, they should be stored with 10% HS at 4°C to maintain ADSC viability. In addition, this was a cost-effective and safe method.