Adipose-derived stem cells: current progress and future perspectives regarding the myogenic differentiation and use in the repair of skeletal muscle defects / 中国组织工程研究

BACKGROUND: Skeletal muscle defect is a major concern of plastic and orthopedic surgeons due to poor regenerative capability of skeletal myocytes and limited clinical treatment. Recently, cell therapy and skeletal muscle engineering based on adipose-derived stem cells (ADSCs) open a new era for skeletal muscle injury repair, which attributes to merits of ADSCs including sufficiency, easy harvest, high yield, strong proliferation and paracrine capability, as well as differentiation potential towards skeletal myoblasts under specific induction. OBJECTIVE: To summarize the process of ADSCs' differentiation towards skeletal myoblasts, to analyze factors that may affect myogenic differentiation of ADSCs and their underlying mechanism, and to discuss the oncological safety of ADSC therapy and limits for clinical application. METHODS: Search in PubMed using the following formula ((myogenic[Title]) OR myogenesis[Title]) AND adipose stem cell[MeSH Terms]) and in SinoMed using ((("adipose tissue"[Title]) AND "Stem cell"[Title]) AND "myo-"[Title]) was done on June 10th, 2017. References related to ADSCs' myogenic differentiation or skeletal muscle repair were included, whereas repeated references were excluded. RESULTS AND CONCLUSION: Forty-seven references in PubMed were selected. Within them, 26 were published in recent 5 years. Forty-seven references in SinoMed met the criteria; however 34 of them were about ADSCs' differentiation towards myocardial cells and 6 were about ADSCs' differentiation towards smooth muscle cells. Eventually, 50 references were included. ADSCs' differentiation towards skeletal myoblasts under specific induction is a complicated process involving the interactions of varieties of genes, proteins and signal pathways.Besides the traditional in vitro chemical induction,conditioned medium or co-culture with myocytes can also facilitate ADSCs' differentiation towards skeletal myoblasts. Chemicals, biomechanics, myogenic regulatory factors, cytokines, growth factors, microRNAs and lncRNA have effects on ADSCs myogenic differentiation. ADSCs can promote the repair of morphology and function of skeletal muscle through direct differentiation or indirect paracrine of cytokines, regulating inflammatory response, suppressing apoptosis, accelerating angiogenesis, and recruiting endogenous stem cells. The future study concerning skeletal muscle repair is expected to address the construction of tissue-engineered muscle by combining various cytokines and growth factors with three-dimensional scaffolds to promote ADSCs' proliferation and differentiation.

Experimental research of discordant tracheal xenotransplantation / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the immunological rejection mechanism of tracheal xenotransplantation and xenografts as potential sources of trachea.</p><p><b>METHODS</b>On SD rat model, a xenotransplanted tracheal from the guinea pig was established by wrapping it in the cervical muscles in situ. It was divided into cryopreserved group and uncryopreserved group. Under the examinations with histochemistry, immunofluorescence (IFL) and flow cytometry (FCM) techniques, the pathomorphological characteristics of the tracheal xenografts and the immunological rejection mechanism were evaluated.</p><p><b>RESULTS</b>The tracheal allotransplantation with cryopreserved grafts wrapped by neck muscles was survived for a longer period. Histological examination revealed normal appearance of the allografts. The tracheal grafts patency was above 80%. However, cryopreserved tracheal xenografts of the guinea pig-to-rat maintained vitality for 14 days in maximum and 13.2 days on average, while the fresh tracheal xenografts only for 9 days in maximum, and 8 days on average. Acute rejection occurred in the tracheal xenotransplantation. A marked mononuclear-macrophage cellular infiltration mixed with eosinophils and lymphocyte was seen in the xenografts. Antibody (IgM, IgG) and complement (C3) deposition were also obviously detected by IFL in the xenografts. CD4 T+ cells and CD8+ T cells increased significantly in the vascular circulation. In all of the xenografts, complete loss of tracheal epithelium was associated with cartilage necrosis. The grafts patency was below 50%. This performance deteriorated with extended time periods. The fresh xenografts performed significantly worse than the cryopreserved xenografts.</p><p><b>CONCLUSIONS</b>Acute rejection, caused by humoral immune reaction mainly integrated with cellular immunity, is the most notable characteristics in the guinea pig-to-rat tracheal xenotransplantation in situ. Cryopreservation can potentially reduce the antigenicity. The low antigenicity may inhibit the immunologic reaction relatively, so that prolonged survival of discordant cryopreserved tracheal xenografts could be achieved.</p>

Pathological genomics of keloid fibroblastic cells / 中华整形外科杂志

<p><b>OBJECTIVE</b>Keloids result from the abnormal repair of the tissues after skin injuries where the pathological overgrowth of large and active fibroblastic cells expands beyond the boundaries of the initiating wound. Imbalanced expression of genes with an as yet unknown regulatory mechanism seems to result in the hypertrophic development of fibroblastic cells and over-productions of collagen. To get information as to genes which function in the actively growing keloid fibroblasts, we have applied a gene expression DNA-microarray technique by analyzing broad range of genes at once in a systematic fashion.</p><p><b>METHODS</b>Differential gene expressions of keloid fibroblastic cell lines against a normal skin fibroblastic cell line, all of the cell lines had been propagated in our lab, were analyzed using a cDNA-microarray technique. mRNA was extracted from the control normal skin cells and the two lines of keloid fibroblastic cells, one from ear-lobe keloid tissue and the other from chest keloid tissue, was subjected to a DNA microarray analysis which includes 1 100 human genes (TaKaRa Intelli Gene Human CHIP 1K Set I) .</p><p><b>RESULTS</b>8 genes were found to be expressed exclusively in ear-lobe keloid fibroblastic cell lines. Cells from chest keloid were detected to express 17 genes, specifically. Coagulation factor II (thrombin) receptor gene, KIAA0367 protein gene, and matrilin-2 gene were found to be the most commonly expressed genes in the keloid cells. Suppressor genes, like melanoma differentiation associated gene-7, Mda-7 (U16261), were expressed in normal skin fibroblasts but were not expressed in keloid fibroblasts may be implicated in the pathogenesis of the keloid lesions.</p><p><b>CONCLUSIONS</b>Genes expressed specifically in keloid cells may be an adequate pathological diagnostic marker for keloids. Further, Identification of genes that cause cells to develop keloid lesions leads us to gene therapy and prevention of keloids.</p>

Experimental research of promoting revascularization of tracheal transplantation by gene therapy / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate methods of promoting revascularization of tracheal transplantation to increase the length of graft.</p><p><b>METHODS</b>Transfer recombinant plasmid pcDNA3.1/myc-His(-)C-bFGF and pCD(2)-VEGF(121) into rabbit cervical muscle by direct injection of plasmid following electric pulses in vivo. Use histochemistry and immunohistochemistry analysis of muscles injected to show the transferred gene expression and the biological effect. Based on the former experiment, conduct gene therapy to the rabbit tracheal autotransplantation wrapped by cervical combined muscles by injecting plasmid DNA directly, combined with gene sutures following electric pulses. Observe and analyze the effect on trachea viability.</p><p><b>RESULTS</b>The recombinant plasmid, pcDNA3.1/myc-His(-)C-bFGF and pCD(2)-VEGF(121) was transferred into muscles flap in vivo successfully. The active protein bFGF and VEGF(121) were expressed at high levels. Blood vessels increased significantly in the muscles, and blood circulation was improved by local angiogenesis. Ten rings tracheal autograft wrapped by transgenic muscles integrating with gene structure revascularized completely, and the rabbit survived for a long period of time. There was significant difference between gene therapy group and control group (P < 0.01). There was no significant difference between bFGF gene therapy group and VEGF(121) gene therapy group. Almost rabbits in the control group died of graft necrosis.</p><p><b>CONCLUSION</b>Tracheal grafts revascularization can be established early by the cervical combined muscles flap wrapping associated with single gene therapy. The length of the tracheal can be increased simultaneously.</p>