The aim of this study was to evaluate the validity and reliability of homeostasis model assessment-insulin resistance (HOMA-IR) index, its reciprocal (1/HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and McAuley's index in hypertensive diabetic patients. In 78 patients with hypertension and type II diabetes glucose, insulin and triglyceride levels were determined after a 12-h fast to calculate these indices, and insulin sensitivity (IS) was measured with the hyperinsulinemic euglycemic clamp technique. Two weeks later, subjects had again their glucose, insulin and triglycerides measured. Simple and multiple linear regression analysis were applied to assess the validity of these indices compared to clamp IS and coefficients of variation between the two visits were estimated to assess their reproducibility. HOMA-IR index was strongly and inversely correlated with the basic IS clamp index, the Mvalue (r ¼ À0.572, Po0.001), M-value normalized with subjects' body weight or fat-free mass and every other clamp-derived index. 1/HOMA-IR and QUICKI indices were positively correlated with the M-value (r ¼ 0.342, Po0.05 and r ¼ 0.456, Po0.01, respectively) and the rest clamp indices. McAuley's index generally presented less strong correlations (r ¼ 0.317, Po0.05 with M-value). In multivariate analysis, HOMA-IR was the best fit of clampderived IS. Coefficients of variation between the two visits were 23.5% for HOMA-IR, 19.2% for 1/HOMA-IR, 7.8% for QUICKI and 15.1% for McAuley's index. In conclusion, HOMA-IR, 1/HOMA-IR and QUICKI are valid estimates of clamp-derived IS in patients with hypertension and type II diabetes, whereas the validity of McAuley's index needs further evaluation. QUICKI displayed better reproducibility than the other indices.

Wnts are a large family of proteins that participate in an array of cellular biological processes such as embryogenesis, organogenesis and tumor formation. These proteins bind to membrane receptor complexes comprised of a frizzled (Fz) G-protein-coupled receptor and other membrane co-receptors forming molecular groups that initiate, at least, three different intracellular signaling cascades leading to nuclear generation of transcription factors which regulate various cellular events. These events result in selective cellular differentiation, reduction or inhibition of the apoptotic mechanisms or changes in the biologic behavior of various cell lines. During the last decade, canonical Wnt signaling has been shown to play a significant role in the control of osteoblastogenesis and bone formation. In several clinical cases, mutations have been found in the Wnt receptor complexes that are associated with changes in bone mineral density and fractures. Loss-of-function mutations in LRP5 receptors cause, osteoporosis-pseudoglioma syndrome, while gain-of-function mutations in the same group lead to high bone mass phenotypes. Furthermore, osteocytes secrete proteins such as sclerostin, which blocks the membrane complex activation by Wnt, resulting in inhibition of bone formation. Studies of knockout and transgenic mouse models for Wnt pathway components have demonstrated that canonical signaling regulates most aspects of osteoblast physiology including commitment, differentiation, bone matrix formation/mineralization and apoptosis as well as coupling to osteoclastogenesis and bone resorption. Future studies in this rapidly growing area of research can possibly lead to the identification of targets of pharmacological intervention useful in the management of osteoporosis. In the present review we summarized the current knowledge related to the various components of the Wnt signaling pathway, the ways they cooperate in inducing and directing transcriptional functions as well as the interacting points with the TGFbeta superfamily. We also outlined a probable working integrating model of the mechanism of bone formation.

Unlike after diet or gastric restrictive surgery, BPD-DS is associated with markedly suppressed ghrelin levels, possibly contributing to the weight-reducing effect of this operation. Sleeve gastrectomy seems to be the main cause of this reduction.

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