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BACKGROUND AND AIM: To evaluate the combined contribution of UCP3-55CT and PPAR?2 Pro12Ala polymorphisms as correlates of BMI, energy expenditure (REE) and substrate oxidation in people with type 2 diabetes. METHODS AND RESULTS: Two independent population with type 2 diabetes were studied: population A, n = 272; population B, n = 269. Based on both UCP3 and PPAR?2 genotypes three groups were created. Carriers of the PPAR?2 Pro12Ala in combination with the CC genotype of UCP3 (ProAla/CC, group 1); carriers of only one of these genotypes (either CC/ProPro or CT-TT/ProAla, group 2); people with neither variants (CT-TT/ProPro, group 3). In both populations BMI (kg/m(2)) was highest in group 1, intermediate in group 2 and lowest in group 3, independent of energy intake (i.e 35.3 ± 6.7 vs 33.4 ± 5.4 vs 31.8 ± 3, p < 0.02, population A; 32.4 ± 4.2 vs 31.7 ± 3.8 vs 30.1 ± 2.7; p < 0.03, population B). People with the ProAla/CC genotype (group 1) showed similar REE, but lower lipid oxidation (10.9 vs 13.9 g/kg fat free mass/day; p = 0.04) and higher carbohydrate oxidation (23.6 vs 15.6 g/kg fat free mass/day; p = 0.02) than carriers of other genotypes. CONCLUSIONS: The combination of UCP3-55 CC and PPAR?2 Pro12Ala genotypes is associated with significantly higher BMI than other PPAR?2-UCP3 genotype combinations, partly due to a reduced ability in lipids oxidation. The relative importance of these mechanism(s) may be different in non diabetic people. Copyright © 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

The aim of this report is to perform a systematic review and qualitative synthesis of the literature to address whether, and to what extent, diet modulates the effects of the Pro12Ala polymorphism of peroxisome proliferator-activated receptor gamma 2 (PPARγ2) on body weight and other measures of adiposity. A systematic search of the literature was conducted, wherein both observational and experimental studies of adults were reviewed. Overall, the results of the observational studies show little consistency. Methodological differences in their design, conduct and analysis may largely account for the apparently discrepant findings. This notwithstanding, the main picture that emerges is that the energy content and composition of the diet may affect BMI, body composition and metabolic parameters in Ala allele carriers more than in Pro/Pro homozygotes. In most studies, carriers of the Ala allele with an obesogenic lifestyle (i.e. high-energy, high-carbohydrate and, to some extent, high-fat diets) are more obese than Pro homozygotes. Well-designed intervention studies with a sufficiently large sample size consistently show that carriers of the Ala allele are more prone to weight loss when exposed to a healthy lifestyle; however, these individuals do not seem to retain these benefits when returning to a sedentary lifestyle and inadequate dieting behaviours. Some key questions in this area of research have emerged. Carefully designed and adequately powered studies are needed, particularly involving the development and validation of standardized tools for the assessment of dietary exposure, including the use of biomarkers, to move the field forward.

Previous association studies of the -55CT polymorphism of the uncoupling protein 3 (UCP3) gene with body mass index (BMI) have provided inconsistent results. The study aim is twofold: (1) to evaluate the association of the -55CT polymorphism of UCP3 with BMI in two independent populations to verify the reproducibility of the finding; (2) to evaluate whether this association is modulated by energy intake.Study participants are 736 males and females with type 2 diabetes belonging to independent populations (N=394 population 1; N=342 population 2). Anthropometry and laboratory parameters were measured; in population 2, energy intake and physical exercise were also assessed.The -55CT polymorphism was associated with a significantly lower BMI in population 1 (27.8±3.9 vs 28.9±4.6 kg m(-2); P0.02), the finding was confirmed in population 2 (that is, 30.3±6.0 vs 32.1±5.9 kg m(-2); P0.01) independent of gender, age, HbA1c, use of drugs and energy intake. To evaluate the role of diet in population 2, the study participants were stratified by genotype and tertiles of energy intake. In both genotype groups, BMI increased with increasing caloric intake with a significant trend (P0.001), the BMI difference between the two genotype groups was large and statistically significant in the lower tertile (27.6 vs 31.2 kg m(-2); P0.001), intermediate in the second tertile and negligible in the upper tertile (32.8 vs 32.9; kg m(-2); nonsignificant). The multivariate regression analysis confirmed a significant interaction between genotype and energy intake as correlates of BMI independent of age, gender, glucose control, physical activity and medications for diabetes (P=0.004).The study replicates in two independent populations the association between the -55CT polymorphism of UCP3 and a lower BMI. This association was modulated by energy intake, thus suggesting that the unmeasured effect of diet may partly account for inconsistencies of prior association studies.

In view of the high incidence of macrovascular diseases in patients with type 2 diabetes mellitus and microalbuminuria, the study evaluates the association of microalbuminuria with fasting plasma Apo B48 levels, a marker of the residual presence of intestinally derived TRLs lipoproteins, thought to be highly atherogenic. We studied 50 patients with type 2 diabetes aged 35–75 years. Exclusion criteria were overt macrovascular disease, overt nephropathy (Glomerular filtration rate (GFR)

Background. Insulin resistance has a role in diabetic nephropathy. The A12 variant of the PPARc2 P121A polymorphism has been firmly associated with reduced risk of insulin resistance, while its role on the risk of albuminuria in patients with type 2 diabetes is uncertain. This study investigated whether the PPARc2 P12A polymorphism modulates the risk of albuminuria in these patients. Methods. We tested the association between the A12 variant and albuminuria in three new case–control studies in diabetic patients from Italy (n ¼ 841, n ¼ 623 and n ¼ 714 patients, respectively) and then performed a meta-analysis of all studies available to date. The nine studies we meta-analysed (six previously published and three presented here) comprised a total of 2376 cases and 4188 controls. Results. In none of the three new studies was a significant association observed with odds ratio (OR) [95% confidence intervals (95% CI)] being 1.115, 0.799 and 0.849 (P ¼ 0.603, 0.358 and 0.518, respectively). At meta-analysis, the overall OR (95% CI) for association between A12 and albuminuria was 0.694 (0.528–0.912). A significant heterogeneity of the genetic effect was observed (P ¼ 0.026), which was totally explained by the different method of urine collection and albuminuria definition utilized across the studies. In fact, most of the effect was observed in the four studies determining albumin excretion rate rather than in those using albumin concentration in a single spot (OR, 95% CI: 0.529, 0.397–0.706, P ¼ 0.0000164 and 0.919, 0.733–1.153, P ¼ 0.47, respectively). Conclusion. The present study shows that the PPARc2 Ala12 variant is significantly associated with a reduced risk of albuminuria among patients with type 2 diabetes.