METABOLISMO E VITAMINA D

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1 CONVEGNO NAZIONALE GIBIS ROMA MAGGIO 2015 METABOLISMO E VITAMINA D Alfredo Scillitani UO Endocrinologia Ospedale Casa Sollievo della Sofferenza

2 Holick MF, NEJM 2007

3 Sindrome Metabolica E un cluster di fattori di rischio che include: Obesità centrale Dislipidemia Ipertensione Insulinoresistenza E diagnosticata quando sono presenti almeno 3 dei seguenti fattori: Obesità centrale Trigliceridi > 150 mg/dl HDL colesterolo < 50 mg/dl PAS> 130 mmhg o PAD> 85 mmhg Glicemia a digiuno > 110 mg/dl L ipovitaminosi D è stata associata ad i fattori di rischio della Sindrome Metabolica

4 Biological mechanisms by which vitamin D influences glycemic control The biological mechanisms by which vitamin D influences glycemic control are not well understood. The proposed mechanisms include: -regulation of glucose-mediated synthesis/secretion of insulin by pancreatic β-cells - enhancing peripheral/hepatic uptake of glucose through both direct and indirect means - reducing inflammation VDR and the 1-α-hydroxylase enzyme are expressed in insulin-secreting pancreatic β-cells and it seems there is a role of 1,25(OH) 2 D in regulating insulin production and secretion VDR signaling facilitates insulin-stimulated glucose uptake in insulin-sensitive tissue In skeletal muscle, adipose tissue and the liver, 1,25(OH) 2 D directly activates the transcription of the human insulin receptor gene and increase expression of the insulin receptor Calcitriol upregulates the expression of glucose transporter 4 (GLUT-4) in skeletal muscle and stimulates GLUT-4 translocation in adipocytes The chronic inflammation that accompanies obesity leads to hyperinsulinemia, IR and β-cell dysfunction/death. This is largely driven by the increased production of inflammatory cytokines, chemokines and adipokines and calcitriol is a strong immunomodulator and improves systemic inflammation

5 Peterson CA, Ther Adv Endocrinol Metab 2014

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7 Vitamin D and risk of future hypertension: meta-analysis of 283,537 participants Relative risk for incident hypertension in individuals in the top compared to the bottom third of baseline vitamin D status in Western populations, Kunutsor SK et al., Eur J Epidemiol 2013

8 Effect of Vitamin D Supplementation on Blood Pressure in Blacks For each 1-ng/mL increase in plasma 25-hydroxyvitamin D, there was a significant 0.2-mm Hg reduction in systolic pressure (P=0.02) Forman JP et al, Hypertension 2013

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10 PREVALENCE OF VITAMIN D DEFICIENCY BY VAT SEX-SPECIFIC TERTILES ACROSS BMI GROUPS Cheng S, Diabetes 2010

11 Impact of vitamin D supplementation during a resistance training intervention on body composition Absolute change (from baseline) in lean mass and fat mass after the 12 week resistance exercise intervention. All values are mean ± SEM s. Placebo ( ) and vitamin D ( ) groups Carrillo AE et al, Clin Nutr 2013

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14 High-Dose Vitamin D Supplementation in People With Prediabetes and Hypovitaminosis D Davidson MB et al, Diab Care 2013

15 High-Dose Vitamin D Supplementation in People With Prediabetes and Hypovitaminosis D Percent of subjects who developed diabetes or reverted to normal Davidson MB et al, Diab Care 2013

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19 Ford ES, Diabetes Care 2005

20 VITAMIN D STATUS AND INDIVIDUAL COMPONENTS OF METABOLIC SYNDROME Vitezova A, EJE 2015

21 Influence of vitamin D supplementation on plasma lipid profiles: A metaanalysis of randomized controlled trials LDL cholesterol Wang H et al, Lipids Health Dis 2012

22 Influence of vitamin D supplementation on plasma lipid profiles: A metaanalysis of randomized controlled trials HDL cholesterol Wang H et al, Lipids Health Dis 2012

23 Influence of vitamin D supplementation on plasma lipid profiles: A metaanalysis of randomized controlled trials Triglycerides. Wang H et al, Lipids Health Dis 2012

24 Prasad 2015

25 Prasad 2015

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