Pluripotent mesenchymal stem cells can undergo lineage-specific differentiation in adult organisms. However, understanding of the factors and mechanisms that drive this differentiation is limited. We show the novel ability of specific oxysterols to regulate lineage-specific differentiation of mesenchymal stem cells into osteogenic cells while inhibiting their adipogenic differentiation. Such effects may have important implications for intervention with osteoporosis.Introduction: Oxysterols are products of cholesterol oxidation and are formed in vivo by a variety of cells including osteoblasts. Novel pro-osteogenic and anti-adipogenic effects of specific oxysterols on pluripotent mesenchymal cells are demonstrated in this report. Aging and osteoporosis are associated with a decrease in the number and activity of osteoblastic cells and a parallel increase in the number of adipocytic cells. Materials and Methods:The M2-10B4 pluripotent marrow stromal cell line, as well as several other mesenchymal cell lines and primary marrow stromal cells, was used to assess the effects of oxysterols. All results were analyzed for statistical significance using ANOVA. Results and Conclusion: Pro-osteogenic and anti-adipogenic effects of specific oxysterols were assessed by the increase in early and late markers of osteogenic differentiation, including alkaline phosphatase activity, osteocalcin mRNA expression and mineralization, and the decrease in markers of adipogenic differentiation including lipoprotein lipase and adipocyte P2 mRNA expression and adipocyte formation. Complete osteogenic differentiation of M2 cells into cells expressing early and late markers of differentiation was achieved only when using combinations of specific oxysterols, whereas inhibition of adipogenesis could be achieved with individual oxysterols. Oxysterol effects were in part mediated by extracellular signal-regulated kinase and enzymes in the arachidonic acid metabolic pathway, i.e., cyclo-oxygenase and phospholipase A 2 . Furthermore, we show that these specific oxysterols act in synergy with bone morphogenetic protein 2 in inducing osteogenic differentiation. These findings suggest that oxysterols may play an important role in the differentiation of mesenchymal stem cells and may have significant, previously unrecognized, importance in stem cell biology and potential therapeutic interventions.

Abstract-Accumulating evidence has suggested the protective role of HDL in cardiovascular disease processes.Calcification is a common feature of atherosclerotic lesions and contributes to cardiovascular complications due to the loss of aortic resilience and function. Recent studies have suggested that vascular calcification shares several features with skeletal bone formation at the cellular and molecular levels. These include the presence of osteoblast-like calcifying vascular cells in the artery wall that undergo osteoblastic differentiation and calcification in vitro. We hypothesized that HDL may also protect against vascular calcification by regulating the osteogenic activity of these calcifying vascular cells. When treated with HDL, alkaline phosphatase activity, a marker of osteogenic differentiation of osteoblastic cells, was significantly reduced in those cells. Prolonged treatment with HDL also inhibited calcification of these cells, further supporting the antiosteogenic differentiation property of HDL when applied to vascular cells. Furthermore, HDL inhibited the osteogenic activity that was induced by inflammatory cytokines interleukin (IL)-1␤ and IL-6 as well as by minimally oxidized LDL. HDL also partially inhibited the IL-6 -induced activation of signal transducer and activator of transcription 3 in calcifying vascular cells, suggesting that HDL may inhibit cytokine-induced signal transduction pathways.

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The authors' data show that there is a current trend of cleft patients receiving treatment at teaching hospitals, with higher costs and decreasing complications. An understanding of such trends and disparities in resource use among various patient, hospital, and geographic settings is important for physicians and policy makers.

Exenatide is a novel and safe treatment option for SBS. It produced substantial improvement in the bowel habits, nutritional status and quality of life of SBS patients. Successful treatment with exenatide may significantly reduce the need for parenteral nutrition and small bowel transplant.

Inflammatory bowel disease (IBD) is associated with a number of extraintestinal manifestations that may involve most organ systems. Extraintestinal manifestations are more common in Crohn disease (CD) and may include rheumatologic, ocular, dermatologic, biliary and pulmonary manifestations. The most common pulmonary manifestations of IBD are drug-induced lung disease. Other manifestations include parenchymal disease, pleuritis and overlap syndromes. We present a case series of 7 patients with non-infectious pulmonary manifestations of IBD, which included cryptogenic organizing pneumonia, usual interstitial pneumonitis (UIP), Langerhan's granulomatosis, and eosinophilic pneumonia. Concurrent extraintestinal manifestations present in these patients included arthralgia, iritis, and pyoderma gangrenosum. In most patients the development of pulmonary disease parallels that of the intestinal disease activity, extraintestinal manifestations and concurrent use of 5-ASA medications.

We demonstrate that ACD in CD is characterized by high serum IL-6 and hepcidin levels, which negatively correlate with Hgb levels. Our data support the hypothesis that IL-6-driven hepcidin production mediates ACD in patients with CD.

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