OBJECTIVE: To evaluate the relationship between plasma leptin and the tumor necrosis factor-a (TNFa), TNF receptor p60 (TNF-R1) and TNF receptor p80 (TNF-R2) concentrations in obese subjects. DESIGN: Case-control study. SETTING: Outpatient's Service for Prevention and Treatment of Obesity at the University Hospital. MEASUREMENTS: Body mass index (BMI), waist circumference, hip circumference, waist-to-hip ratio (WHR), fasting plasma glucose, fasting plasma insulin, homeostasis model assessment of insulin resistance (HOMA IR), plasma leptin, TNFa a, TNF-R1 and TNF-R2 concentrations were evaluated in obese subjects (n 42) and in age-and gendermatched, lean healthy controls (n 16). RESULTS: In obese subjects, fasting plasma glucose and insulin, HOMA IR, plasma leptin, TNFa a, TNF-R1 and TNF-R2 concentrations were signi®cantly higher than in controls. Furthermore, females showed higher leptin, TNF-R1 and TNF-R2 plasma concentrations compared to males, in both control and obese subjects. In control subjects, plasma leptin concentrations showed a direct correlation with BMI (r 0.74, P`0.001), hip circumference (r 0.94, P`0.001), TNF-R1 (r 0.79, P`0.001) and TNF-R2 (r 0.64, P`0.01), and a negative correlation with WHR (r À À0.58, P`0.05). In obese subjects, we found a direct correlation between plasma leptin concentrations and BMI (r 0.67, P`0.001), hip circumference (r 0.66, P`0.001), fasting glucose (r 0.37, P`0.05), fasting insulin (r 0.31, P`0.05), HOMA IR (r 0.38, P`0.05), TNF-R1 (r 0.71, P`0.001) and TNR-R2 (r 0.66, P`0.001), while a negative correlation was found between circulating leptin and WHR (r À À0.44, P`0.01). In multivariate analysis, plasma leptin concentrations were signi®cantly associated with BMI (P 0.015) and gender (P 0.047) in the control group, while in obese subjects, plasma leptin showed a signi®cant association with BMI (P 0.019) and TNF-R1 (P 0.012). CONCLUSIONS: Our results are consistent with the hypothesis that the TNFa a system could be involved in the regulation of plasma leptin concentrations in obese subjects.

Extracellular matrix alterations have been suggested to be part of the early events occurring in Autosomal Dominant Polycystic Kidney Disease (ADPKD), a disease characterized by formation of renal cysts and progressive renal failure. Here we report that cDNA array analysis identified beta(4) integrin aberrant expression in ADPKD cells. Furthermore, laminin 5 (Ln-5), the main alpha(6)beta(4) integrin ligand, was also found to be abnormally expressed in ADPKD. Studies performed with ADPKD cyst-lining epithelial cells (CC) by comparison with normal tubular cells indicate that integrin alpha(6)beta(4)-Ln-5 interactions are involved in cellular events of potential importance for cystogenesis: 1) laminin 5 is a preferential adhesion substrate for CC, mainly through alpha(6)beta(4) interaction, 2) CC increased haptotactic and chemotactic motility depends on the presence of Ln-5 and requires integrin alpha(3)beta(1) cooperation, and 3) CC haptotactic or chemotactic migration is specifically increased by mAb-mediated beta(4) integrin ligation, through an alpha(3)beta(1) integrin-dependent and independent pathway, respectively. These results highlight the role of Ln-5 and alpha(6)beta(4) integrin in adhesive and motility properties of cyst-lining epithelial cells, and further suggest that integrins and extracellular matrix modifications may be of general relevance to kidney epithelial cell cyst formation.

Abnormal renal reabsorption of sodium (Na(+)) is likely to play a role in the pathogenesis of salt-sensitivity. In the kidney, chloride channels CLC-Ka (gene CLCNKA) and CLC-Kb (gene CLCNKB) and their subunit Barttin (gene BSND) have important effects on the control of Na(+) and water homeostasis. We investigated if single nucleotide polymorphisms (SNPs) or haplotypes within CLCNKA, CLCNKB and BSND loci affect salt-sensitivity in hypertensive subjects. Associations between blood pressure (BP) change after Na(+)-load and 15 SNPs spanning the length of CLCNKA and CLCNKB and six SNPs spanning the length of BSND were studied in 314 never treated essential hypertensives who underwent an i.v. infusion of saline (300 mm NaCl in 2 l H(2)O in 120 min). Four SNPs were significantly associated with BP change after Na-load. Rs848307 (P = 0.0026) and rs1739843 (P = 0.0023) map upstream the 5' of CLCNKA. Non-coding Rs1010069 (P = 0.0006) and non-synonymous rs1805152 (Thr447Ala; P = 0.0078) map within CLCNKA. Moreover, basal plasma renin activity and heart rate (measured before Na-load) were significantly lower in patients carrying the alleles associated with the larger mean BP increase after Na-load, indicating that such alleles are associated with chronic volume expansion. This study supports the candidacy of CLCNKA as a new susceptibility gene for salt-sensitivity.

In patients with essential hypertension, elevated soluble E-selectin (sE-selectin) levels may indicate endothelial cell injury or activation. We therefore sought to ascertain whether arterial blood pressure increased by the cold pressor test can modify serum concentrations of sE-selectin and other soluble forms of adhesion molecules, such as soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1), or the expression of any adhesion molecules in circulating monocytes and lymphocytes. Our findings show that levels of sE-selectin, sVCAM-1, and sICAM-1 are higher in patients with essential hypertension than in normotensive subjects (sICAM-1, 380±52 versus 262±96 ng/mL, P <.05; sVCAM-1, 720±52 versus 625±38 ng/mL, P <.05; and sE-selectin, 75±21 versus 61±22 ng/mL, P <.05). Furthermore, in normotensive and hypertensive patients, the cold pressor test caused an increase in serum concentrations of sICAM-1, sVCAM-1, and sE-selectin, but it did not cause changes in the expression of adhesion molecules in circulating monocytes and lymphocytes. High arterial blood pressure may therefore increase the production of serum adhesion molecules, probably through endothelial activation.