[카테고리:] <span>생명연장</span>

요약 : 
Ageing brings about the progressive decline in cognitive function and physical activity, along with losses of stem cell population and function. Although transplantation of muscle derived stem/progenitor cells extended healthspan and lifespan of progeria mice, such effects in normal animals were not confirmed. Human amniotic membrane-derived mesenchymal stem cells (AMMSCs) or adipose tissue-derived mesenchymal stem cells (ADMSCs) (1 × 106 55 cells/rat) were intravenously transplanted to 10-month-old male F344 rats once a month for their life-long periods. Transplantation of AMMSCs and ADMSCs improved cognitive and physical functions of naturally-ageing rats, extending lifespan by 23.4% and 31.3%, respectively. The stem cell therapy increased the concentration of acetylcholine, and recovered neurotrophic factors in the brain and muscles, leading to restoration of microtubule-associated protein 2, cholinergic and dopaminergic nervous systems, microvessels, muscle mass as well as antioxidative capacity. The results indicate that repeated transplantation of AMMSCs and ADMSCs elongate both healthspan and lifespan, which could be a starting point for anti-ageing or rejuvenation effects of allogeneic or autologous stem cells with minimum immune rejection.

요약 : 
The amniotic epithelium consists of cells exhibiting mature epithelial cell characteristics, but also varying degrees of stemness. We tested the hypothesis that induction of epithelial-to-mesenchymal transition (EMT) in
amniotic epithelial cells (AECs) derived from human placenta enhances their capacity to support the ischemic myocardium. In response to incubation with transforming growth factor-b1 (TGF-b1) protein, AECs lost their
cobblestone morphology and acquired a fibroblastoid shape, associated with downregulation of E-cadherin, upregulation of N-cadherin, Akt phosphorylation, and intracellular periostin translocation. EMT–AECs displayed greatly enhanced mobility and secreted gelatinase activity compared with naive AECs. The surface presentation of CD105 and CD73 decreased, and RNA microarray analysis mirrored the loss of epithelial characteristics and transcriptional profile. Unmodified AECs and EMT–AECs were then injected intramyocardially in fully immunocompetent mice after permanent LAD ligation, and heart function was followed by MRI as well as 2D speckle tracking echocardiography after 4 weeks. EMT–AEC-treated infarct hearts displayed better global systolic function and improved longitudinal strain rate in the area of interest. Although no signals of human cells were detectable by histology, infarct size was smaller in EMT–AEC-treated hearts, associated with fewer TUNEL-positive cells and upregulation of periostin, while blood vessel density was increased in both ACE- and EMT–AEC-treated hearts. We conclude that EMT enhances the cardioprotective effects of human AECs