To investigate hemodynamic and hormonal effects of ghrelin, a novel growth hormone (GH)-releasing peptide, we gave six healthy men an intravenous bolus of human ghrelin (10 microg/kg) or placebo and vice versa 1-2 wk apart in a randomized fashion. Ghrelin elicited a marked increase in circulating GH (15-fold). The elevation of GH lasted longer than 60 min after the bolus injection. Injection of ghrelin significantly decreased mean arterial pressure (-12 mmHg, P < 0.05) without a significant change in heart rate (-4 beats/min, P = 0.39). Ghrelin significantly increased cardiac index (+16%, P < 0.05) and stroke volume index (+22%, P < 0.05). We also examined ghrelin receptor [GH secretagogues receptor (GHS-R)] gene expression in the aortas, the left ventricles, and the left atria of rats by RT-PCR. GHS-R mRNA was detectable in the rat aortas, left ventricles, and left atria, suggesting that ghrelin may cause cardiovascular effects through GH-independent mechanisms. In summary, human ghrelin elicited a potent, long-lasting GH release and had beneficial hemodynamic effects via reducing cardiac afterload and increasing cardiac output without an increase in heart rate.
Eldecalcitol is more efficacious than alfacalcidol in preventing vertebral and wrist fractures in osteoporotic patients with vitamin D sufficiency, with a safety profile similar to alfacalcidol.
Mesenchymal stem cells (MSCs) are attractive cell sources in regenerative medicine. We examined the effects of topical MSCs implantation on an experimental model of inflammatory bowel disease. Putative MSCs, isolated from bone marrow aspirates of male rats by dish adherence and expanded in vitro, were characterized by flow cytometry, reverse transcriptionpolymerase chain reaction, enzyme-linked immunosorbent assay, and differentiation assays. Experimental colitis was induced by intraluminal instillation of 2,4,6-trinitrobonzene sulfonic acid (TNBS) in the colons of male rats. The putative MSCs and unselected fresh bone marrow cells were injected into the colonic submucosa surrounding the area exposed to TNBS. The healing process of the injury was examined macroscopically and immunohistologically. Multipotent MSCs positive for CD29 and CD90, and negative for CD31 and CD34, were implanted into colon tissue surrounding the lesion; a majority of the engrafted cells were positive for vimentin. The implantation significantly accelerated healing of the damaged mucosa compared with vehicle-injected controls. The MSCs expressed vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-1 in vitro and after the implantation. In conclusion, we found that MSCs were successfully topically implanted in the colon and that they were associated with accelerated healing of TNBS-induced colitis. The beneficial effects of the MSCs might be mediated, at least in part, by their ability to differentiate into colonic interstitial cells and by their ability to provide VEGF and TGF-1 to the injured area.
High-fat diet (HFD) could induce prostate cancer progression. The aim of this study is to identify mechanisms of HFD-induced prostate cancer progression, focusing on inflammation. We administered HFD and celecoxib to autochthonous immunocompetent Pb-Cre;(fl/fl) model mice for prostate cancer. Tumor growth was evaluated by tumor weight and Ki67 stain, and local immune cells were assessed by flow cytometry at 22 weeks of age. Cytokines which correlated with tumor growth were identified, and the changes of tumor growth and local immune cells after inhibition of the cytokine signals were evaluated in the mice. IHC analyses using prostatectomy specimens of obese patients were performed. HFD accelerated tumor growth and increased the myeloid-derived suppressor cells (MDSCs) fraction and M2/M1 macrophage ratio in the model mice. Celecoxib-suppressed tumor growth, and decreased both local MDSCs and M2/M1 macrophage ratio in HFD-fed mice. HFD-induced tumor growth was associated with IL6 secreted by prostatic macrophages, as were phosphorylated STAT3 (pSTAT3)-positive tumor cells. Anti-IL6 receptor antibody administration suppressed tumor growth, and decreased local MDSCs and pSTAT3-positive cell fractions in HFD-fed mice. The tumor-infiltrating CD11b-positive cell count was significantly higher in prostatectomy specimens of obese than those of nonobese patients with prostate cancer. HFD increased MDSCs and accelerated prostate cancer tumor growth via IL6/pSTAT3 signaling in the mice. This mechanism could exist in obese patients with prostate cancer. IL6-mediated inflammation could be a therapeutic target for prostate cancer. .
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