Nonadherent culture method promotes MSC-mediated vascularization in myocardial infarction via miR-519d/VEGFA pathway.

BACKGROUND: Mesenchymal stem cells (MSCs) can provide therapeutic benefits for myocardial infarction (MI) recovery; however, the molecular mechanism by which MSCs improve the heart function is unclear. METHODS: Microarray analysis was performed to examine the expression profiling of human MSCs (hMSCs) grown as adherent cultures (AC-hMSCs) or nonadherent cultures on ultra-low-adherent plates (nonAC-hMSCs). Real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, and enzyme-linked immunosorbent assays (ELISA) were used to assess VEGFA expression and secretion in the AC-hMSCs and nonAC-hMSCs. The paracrine effect of VEGFA-overexpressing AC-MSCs (AC-VEGFA-hMSCs) or VEGFA-knockdown nonAC-hMSCs (nonAC-shVEGFA-hMSCs) on the angiogenic ability of human umbilical vein endothelial cells (HUVECs) was evaluated using tube formation assay. AC-VEGFA-hMSCs or nonAC-shVEGFA-hMSCs were transplanted into myocardial infarction rats to investigate the therapeutic effect of AC-VEGFA-hMSCs or nonAC-shVEGFA-hMSCs. Luciferase reporter assay was used to confirm the association of VEGFA with miR-519d. RESULTS: Microarray analysis revealed that VEGFA is downregulated in AC-hMSCs compared to nonAC-hMSCs. Functional assays revealed that high levels of VEGFA produced from AC-VEGFA-hMSCs increased the tube formation capacity of HUVECs in vitro, improved angiogenesis and cardiac performance, and reduced infarct size in a rat MI model. Low levels of VEGFA secretion from nonAC-shVEGFA-hMSCs had the opposite effects. Mechanistically, we found that miR-519d directly targets VEGFA. High levels of VEGFA secreted from VEGFA-overexpressing nonAC-hMSCs abolished the repressive effect of miR-519d on HUVEC angiogenesis. CONCLUSION: Our findings indicate that nonadherent culture-induced secretion of VEGFA plays an important role in MSCs via the miR-519d/VEGFA pathway and may provide a novel therapeutic strategy for MI treatment.

Removal from adherent culture contributes to apoptosis in human bone marrow mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are routinely isolated due to their adherence to tissue culture plates and their in vitro growth characteristics. Expansion of MSCs in adherent cultures is the only way to obtain sufficient cells for use in either clinical or research settings. MSCs have tremendous potential in myocardial repair treatment by cell therapy techniques, however, a large number of MSCs die from apoptosis following transplantation. Previous studies have examined the factors contributing to the survival of transplanted cells, but little is known about the effect of removal from adherent culture conditions on apoptosis of the MSCs. In the present study, human bone marrow MSCs were expanded in adherent cultures. Then apoptosis rates were examined at different time points in MSCs cultured in nonadherent conditions (ultra­low­adherence plates) compared with MSCs cultured in adherent conditions (standard tissue culture plates). Flow cytometry analysis suggested that cell apoptosis increased when MSCs were cultured in nonadherent culture conditions. In addition, western blot and reverse transcription­quantitative polymerase chain reaction analyses demonstrated that caspase­3, ­7 and ­9 were involved in this process. The present study demonstrated that loss of culture adherence increases apoptosis of human MSCs. The present findings may provide new insight into the factors affecting MSC survival after transplantation.

Personalized management of anastomotic leak after surgery for esophageal carcinoma.

OBJECTIVE: To summarize the management of anastomotic leak following surgery for esophageal carcinoma. METHODS: The medical records of the patients developing digestive tract leak after surgery for esophageal carcinoma in our hospital from January 2003 to March 2011 were retrospectively analyzed. RESULTS: A total of 36 patients were included, in whom 13 developed cervical anastomotic leak, 18 had intra-thoracic anastomotic leak, and 5 had intra-thoracic gastric necrosis. Of these patients, 7 were treated with resurgery, 6 with esophageal stent implantation, and 23 with conservative treatment. Treatment lasted for 5 to 181 days, averagely 47.0 +/- 31.9 days. After management, 9 patients died (25.0%). Among seven patients with resurgery, four had deceased, two were cured, and one developed leak again and was switched to conservative treatment until discharged. All the 6 patients treated with stent implantation were cured. Of the 24 patients receiving conservative treatment (including one switched from resurgery), 18 (75.0%) were cured and 1 was not cured but survived. CONCLUSIONS: Anastomotic leak following surgery for esophageal carcinoma should be treated individually based on the onset time, location, size, and extent of the leakage. Conservative treatment is still a safe and effective method. The efficacy of stent implantation needs further investigation to confirm.