Short-term administration of flavanol-rich cocoa decreases blood pressure levels and insulin resistance in healthy individuals

XVIII S.I.S.A. National Congress

294 SHORT-TERM ADMINISTARTION OF FLAVANOL-RICH COCOA DECREASES BLOOD PRESSURE LEVELS AND INSULIN RESISTANCE IN HEALTHY INDIVIDUALS Grassi D, Lippi C, Pasqualetti P, Casale R, Properzi G, Croce G, Broccoletti S, Valeri L, Passacquale G, Garofalo A, Desideri G, Ferri C. Department of Internal Medicine, University of L'Aquila, L'Aquila, Italy.

NOT FORWARDED

Objective: Flavanols contained in dark chocolate bars have been suggested to protect the vascular endothelium by improving nitric oxide (NO) availability. Aim of this study was to compare the effects of either dark (flavanol-rich) or white (flavanol-free) chocolate bars on systolic and diastolic blood pressure (BP) levels and the glucose and insulin responses to an oral glucose tolerance test (OGTT) in healthy subjects. After a cocoa-free run-in phase of 7 days 15 healthy individuals (7 males, mean age 33.9+7.6 years) were randomly assigned to receive either 100 g dark chocolate bars containing 500 mg flavanols or 90 g white chocolate bars containing no flavanols, for 15 days. Successively, subjects entered a further cocoa-free wash-out phase of 7 days and then were crossed over to the other condition. BP and heart rate were measured daily, in seated position. At the end of each period, OGTTs were performed to calculate HOMA-IR and QUICKI. BP significantly decreased after 15 days of dark (systolic BP: - 5.8+4.3 mmHg, p=0.04; diastolic BP: - 4.2+3.3 mmHg, p=0.03) but not white chocolate ingestion (systolic BP: - 0.2_+1.6 mmHg, n.s.; diastolic BP: - 0.3+1.8 mmHg, n.s.). Dark but not white chocolate ingestion also significantly decreased HOMA-IR (from 1.53+0.69 to 0.94-+0.42, p=0.009) and increased QUICKI (from 0.366+0.029 to 0.398+0.039, p=0.016). Conclusions: Our results demonstrated that dark (flavanol-rich) but not white (fiavanol-free) chocolate bars decreased BP levels and improved insulin sensitivity in healthy individuals. We cannot state whether or not these effects were due to increased NO availability. Nevertheless, our study supports the hypothesis that cardiovascular benefits may derive from dark chocolate ingestion.

Plasma viscosity in elderly hypertensive men: the role of systolic and pulse pressure

Resveratrol does not affect inflammatory enzyme function in vascular smooth muscle cells from diabetic rats

Ciuffetti G., Schillaci G., Lombardini R., Pirro M, Vaudo G., Mannarino E.

Andrea Cignarella, Chiara Bolego, Christian Pinna, Claudia Minici, Lina Puglisi

Unit of Internal Medicine, Angiology and Atherosclerosis - University of Perugia Atherosclerosis is increasingly recognized as an inflammatory vascular disease, and blood hypertension has been suggested to exert a proinflammatory action. Whether plasma viscosity (PV), a major determinant of blood flow in microcirculation and a marker of systemic inflammation and cardiovascular risk, is increased in elderly subjects with isolated systolic hypertension is not known. In addition, the correlation of blood pressure (BP) and its pulsatile component, i.e. pulse pressure (PP), with PV levels independent of the confounding effect of other cardiovascular risk factors has not been investigated. To this aim, we measured PV in 108 eldedy men with never treated, uncomplicated isolated systolic hypertension, and in 60 healthy matched normotensive control subjects. PV values were higher in hypertensive subjects than in controls (1.39+/-0.10 vs 1.34+/-0.09 cP, p<0.01). PV showed a significant direct bivariate correlation with both systolic BP (r=0.32) and PP (r=0.36, both p<0.01), but not with diastolic BP (r=0.09, p=n.s.). PV was also directly associated with serum low-density lipoprotein cholesterol and triglycerides. In a multivariate analysis, PP was a significant predictor of PV levels when a consistent number of cardiovascular risk factors were simultaneously controlled for. In conclusion, PV is elevated in elderly subjects with isolated systolic hypertension. Systolic BP and PP appear to be major determinants of PV levels in these patients, independent of the potential proinflammatory action of traditional cardiovascular risk factors.

Department of Pharmacological Sciences, University of Milan Several studies have reported the cardioprotective effects of resveratrol, a polyphenolic antioxidant abundant in grapes. This compound can interact with estrogen receptors. Since 17?-estradiol shows anti-inflammatory activity in vascular cells, we investigated the effects of resveratrol on the functional expression of inflammatory enzymes in vascular smooth muscle cells (SMC) obtained from normoglycaemic and also from diabetic rats, as a model of inflammatory vascular dysfunction. Unexpectedly, treatment with increasing concentrations of resveratrol (0.1-100 pM) enhanced functional expression of inducible NO synthase (iNOS) after a 24-h inflammatory challenge with cytokines in both control and diabetic SMC. Similady, the structurally related isoflavone genistein increased iNOS immunoreactivity but had no effect on iNOS activity. Even when a shorter inflammatory challenge (4 hours) was applied, resveratrol still enhanced iNOS production. These effects on iNOS protein were mediated, at least in part, by estrogen receptors because the estrogen receptor antagonist ICI 182,780 reversed resveratrol action. Cyclooxygenase-2 protein was detectable in unstimulated SMC and its expression was not affected by resveratrol treatment in the presence of cytokines. However, treatment with resveretrol, but not 17?-estradiol, reduced prostaglandin E2 accumulation in the medium of control, but not diabetic SMC. These results indicate that resveratrol, at concentrations likely to be achieved in vivo, showed only limited anti-inflammatory activity in cytokine-treated vascular SMC from normoglycaemic rats and no sign of protective activity in SMC from diabetic rats.