CD36 is a class B scavenger receptor recognizing a variety of ligands including long-chain fatty acids and modified LDL. We investigated whether genetic variability at this locus is a determinant of free fatty acid (FFA) plasma levels and risk of coronary artery disease (CAD) in Caucasians. Typing of 21 polymorphic markers, evenly spanning the CD36 gene, revealed two linkage disequilibrium (LD) blocks that could be tagged by five polymorphisms (-33137A>G, -31118G>A, 25444G>A, 27645del>ins and 30294G>C). In 585 non-diabetic individuals of Caucasian origin, the 30294G>C polymorphism was significantly associated with FFA levels (P = 0.02)--an effect that was especially visible among men (P = 0.009). A similar association was observed in this gender at -33137 (P = 0.008) and -31118 (P = 0.028). When the five tag polymorphisms were considered together, men carrying the AGGIG haplotype had 31% higher FFA (P = 0.0002) and 20% higher triglycerides (P = 0.025) than non-carriers. The same haplotype was associated with increased risk of CAD in 197 type 2 diabetic individuals from the US (OR = 2.3, 95% CI 1.2-4.2). A similar tendency was observed in a group of 321 type 2 diabetic individuals from Italy (OR = 1.4, 0.9-2.3), resulting in an overall relative risk of 1.6 (1.1-2.3, P = 0.015) in the two populations considered together. By targeted resequencing, we identified a common variant in the CD36 promoter that is in strong LD with the AGGIG haplotype and could be partly responsible for these findings. In conclusion, this comprehensive study of CD36 variability indicates that the common polymorphisms at this locus modulate lipid metabolism and cardiovascular risk in Caucasians.

Orexins A and B are two hypothalamic peptides that increase food intake and body weight and probably play a role in the sleep regulation. They act through two subtypes of G protein-coupled receptors, called OX1-R and OX2-R. OX1-R selectively binds orexin-A, whereas OX2-R is nonselective for both orexins. Orexins did not affect the in vitro secretion of either catecholamine or aldosterone from human adrenals. Conversely, orexin A, but not orexin B, concentration dependently increased basal cortisol secretion from dispersed adrenocortical cells; the maximal effective concentration was 10(-8) mol/L. Orexin A (10(-8) mol/L) enhanced the cortisol response to maximal effective concentrations (10(-9) mol/L) of angiotensin II and endothelin-1, but only to low concentrations of ACTH (10(-12)/10(-11) mol/L). Orexin A (10(-8) mol/L) increased basal cAMP release by dispersed adrenocortical cells, and the effect was blocked by the adenylate cyclase inhibitor SQ-22536. The cortisol response to 10(-8) mol/L orexin A was unaffected by the ACTH receptor antagonist corticotropin-inhibiting peptide, but was abolished by either SQ-22536 or the protein kinase A inhibitor H-89. RT-PCR demonstrated high levels of OX1-R messenger ribonucleic acid and very low levels of OX2-R messenger ribonucleic acid in human adrenal zona fasciculata-reticularis and adrenal medulla. Collectively, our findings suggest that orexins selectively stimulate glucocorticoid secretion from human adrenocortical cells, acting through OX1-R coupled with the adenylate cyclase-dependent signaling pathway.

visfatin promoter polymorphism is associated with low-grade inflammation and type 2 diabetes. Obesity. 2006;14: 2119 -2126. Visfatin (also known as pre-B cell colony-enhancing factor, or PBEF) is a pro-inflammatory adipokine expressed predominantly in visceral fat. We investigated whether polymorphisms at the visfatin/PBEF locus influence the risk of type 2 diabetes (T2D). Linkage disequilibrium analysis of 52 single nucleotide polymorphisms spanning the entire gene (34.7 kb) plus 20.5 kb of the upstream region and 25.5 kb of the downstream region revealed a single haplotype block that could be tagged by seven single nucleotide polymorphisms. These seven tags were typed in a group of T2D patients (n ϭ 814) and a group of non-diabetic controls (n ϭ 320) of white origin. A significant association was observed at Ϫ948CϾA, with minor allele frequencies of 0.157 in T2D cases and 0.119 in non-diabetic controls (p ϭ 0.021). In a non-diabetic population (n ϭ 630), the same Ϫ948 allele that conferred increased risk of T2D was significantly associated with higher plasma levels of fibrinogen and C-reactive protein (p ϭ 0.0022 and 0.0038, respectively). However, no significant associations were observed with BMI, waist circumference, serum glucose levels, or fasting insulin levels. Our findings suggest that the visfatin/PBEF gene may play a role in determining T2D susceptibility, possibly by modulating chronic, low-grade inflammatory responses.

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GF treatment improves both insulin action and flow-mediated vasodilatation in type 2 diabetic patients. The reduction of TG concentration allows the simultaneous correction of two important components of the metabolic syndrome.