WISP1 Is a Marker of Systemic and Adipose Tissue Inflammation in Dysmetabolic Subjects With or Without Type 2 Diabetes.

CONTEXT: Wnt1-inducible signaling pathway protein 1 (WISP1) is a novel adipokine participating in adipose tissue (AT) dysfunction; so far, no data on WISP1 in diabetes are available. OBJECTIVES: To evaluate plasma WISP1 in subjects with type 2 diabetes (T2D) and its correlates linked to AT inflammation. DESIGN AND PARTICIPANTS: For this cross-sectional study, 97 consecutive dysmetabolic patients were recruited at the diabetes outpatient clinics of Sapienza University in Rome; 71 of them had T2D, with (n = 35) or without (n = 36) obesity, and 26 were obese patients without diabetes. Twenty-one normal-weight nondiabetic individuals were enrolled as a control group. Study participants underwent clinical workup and blood sampling for metabolic/inflammatory characterization; magnetic resonance imaging (MRI) data on subcutaneous AT and visceral AT (VAT) area, hepatic fat content, and VAT homogeneity were available for most diabetic patients. RESULTS: Plasma WISP1 significantly increased throughout classes of obesity and correlated with greater VAT area, interleukin-8 (IL-8), and lower adiponectin levels, without differing between diabetic and nondiabetic participants. Higher IL-8 was the main determinant of increased WISP1. MRI-assessed VAT inhomogeneity was associated with higher WISP1, IL-8 and C-reactive protein levels, independent of obesity; high WISP1 strongly predicted VAT inhomogeneity (P < 0.001). CONCLUSIONS: WISP1 levels are increased in obese persons and are directly related to adiposity, independent of glycemic status or insulin resistance; moreover, they are strongly associated with increased plasma IL-8 and signal abnormalities of VAT. The overall data add insights to the mechanisms underlying metabolic alterations and may open a scenario for innovative therapeutic approaches for diabetes prevention and care.

Hypovitaminosis D is independently associated with metabolic syndrome in obese patients.

BACKGROUND: Metabolic syndrome (MS) and hypovitaminosis D represent two of the most diffuse condition worldwide, reaching pandemic proportions in industrialized countries, and are both strongly associated with obesity. This study set out to evaluate the presence of an independent association between hypovitaminosis D and MS in an adult population of obese subjects with/without MS. METHODS: We recruited 107 consecutive obese subjects, 61 with MS (age(mean±SD) 45.3±13.3 years, BMI(mean±SD): 43.1±8.3 kg/m(2)) and 46 without MS (age: 41.8±11.5, p = n.s., BMI:41.6±6.5 kg/m(2), p = n.s.) comparable for sex, BMI, waist circumference and body fat mass, evaluated by bioimpedentiometry. 25(OH) vitamin D3 levels were measured by colorimetric method. Insulin resistance was estimated by fasting blood insulin, HOMA-IR and ISI. RESULTS: Serum 25(OH)D3 levels were significantly lower in MS obese patients than in obese subjects without MS (median(range) 13.5(3.3-32) vs 17.4(5.1-37.4), p<0.007). Low 25(OH)D3 levels correlated with glycaemia (p<0.007), phosphate (p<0.03), PTH (p<0.003) and the MS (p<0.001). Multivariate model confirmed that low 25(OH)D3 levels were associated with the diagnosis of MS in obese patients independently from gender, age, serum PTH and body fat mass. After stratifying the study population according to 25(OH)D3 concentrations, patients in the lowest quartile showed a markedly increased prevalence of MS compared to those in the highest quartile (OR = 4.1, CI 1.2-13.7, p = 0.02). CONCLUSIONS: A powerful association exists between hypovitaminosis D and MS in obese patients independently from body fat mass and its clinical correlates. This indicates that the association between low 25(OH) D3 levels and MS is not merely induced by vitamin D deposition in fat tissue and reinforces the hypothesis that hypovitaminosis D represent a crucial independent determinant of MS.