Impact of a high fructose diet on visceral adiposity functionality.

A ALZAMENDI; A GIOVAMBATTISTA; A RASCHIA; C MARRA; O REBOLLEDO; RC GAILLARD; E SPINEDI

San Francisco, California, EE UU

Congreso; ENDO 2008, The Endocrine Society’s 90th Annual Meeting; 2008

ENDO, Endocrine Society

Impact of a high fructose diet on visceral adiposity functionality. A Alzamendi1, A Giobambattista1, A Raschia2, C Marra3, O Rebolledo2, RC Gaillard4 and E Spinedi1. 1Neuroendocrinology, IMBICE (CONICET-CICPBA), La Plata, BA, Argentina, 1900; 2CENEXA (CONICET-UNLP), La Plata, BA, Argentina, 1900; 3INIBIOLP (CONICET-UNLP), La Plata, BA, Argentina, 1900 and 4Endocrinology, Diabetology & Metabolism, University Hospital (CHUV), Lausanne, Vaud, Switzerland, 1011. The aim of the present work was to evaluate changes in lipid metabolism and endocrine function of the visceral adipose tissue (VAT) in male rats with metabolic syndrome (MS) induced by a high fructose diet (HFD) (10% in the drink water [F10]) during three weeks. For this purpose, normal Wistar (F0) and F10 rats were sacrificed in basal condition and trunk blood was collected. Immediately after, VAT pads were dissected to determine in vitro the composition and release (by HPLC) of non-esterified fatty acids (NEFA) and to isolate adipocytes. These cells were 30 min incubated, without and with insulin (0.1-10 nM), triglycerides (0.99±0.07 vs. 0.74±0.06 g/l) and several adipokines [leptin (6.29±0.64 vs. 3.37±0.52 ng/ml), adiponectin (29.41±2.21 vs. 13.65±0.33 mg/ml) and PAI-1 (2.89±0.54 vs. 1.56±0.15 ng/ml)], with no changes in TNFá, CRP, total cholesterol, glucose and insulin peripheral concentrations. After in vitro incubation of VAT pads from both groups, a significant increase in NEFA secretion was observed in the F10 group (0.821±0.083 vs. 0.503±0.065 mg NEFA/g VAT; p<0.02), and in the proportion of saturated NEFA (71.0±1.1 vs. 50.9±1.0 %; p<0.001). These changes were accompanied by a significant decrease in unsaturated NEFA (30.7±1.1 vs. 56.1±2.0 %; p<0.001). VAT leptin mRNA expression was 70% higher in F10 rats (p<0.05 vs. F0) and, conversely, VAT IRS-1 and IRS-2 mRNAs were 8 and 21% diminished, respectively (p<0.05 vs. F0). Finally, adipocytes from VAT of F10 rats spontaneously released a higher concentration of leptin (0.36±0.02 vs. 0.22±0.01 ng/ml; p<0.05), and displayed an impaired (p<0.05 vs. F0) response in leptin output after 30 min stimulation with graded concentrtions of insulin. Our study indicates that HFD administration for three weeks induces a precocious development of changes in lipids and several adipokines circulating levels, and modification in VAT function (such as NEFA composition and release, leptin secretion, and diminished adipocyte sensitivity to insulin stimulation due to, at least in part, a reduction in its intracellular mediators). We conclude that changes in VAT functionality could be contributing to induce the overall endocrine-metabolic dysfunction characterizing the MS.