Tumor suppressor protein p53 has been demonstrated to regulate genes involved in energy generating metabolic pathways and apoptosis. To date, a new field of research is the involvement of TP53 codon 72 (Arg72Pro) polymorphism in the diabetic disease. The aim of this study was to evaluate whether the genotype and the related genetic models of Arg72Pro polymorphism of TP53 (rs1042522) are associated with insulin resistance and its metabolic parameters in diabetic and non-diabetic subjects. We examined 335 type 2 diabetic patients (65.5 ± 8.4 years) and 367 non-diabetic subjects (60.5 ± 11.7 years). The results were validated in a validation sample consisting of 199 type 2 diabetic (66.2 ± 8.5 years) and 224 non-diabetic subjects (61.2 ± 12.7 years). In the study sample, the analysis of covariance, adjusted for the effects of age, gender and BMI, showed a significant genotype-diabetes effect on insulin resistance evaluated by HOMA-IR (p = 0.038). This result was mediated by variations in fasting plasma insulin (p = 0.027), as no TP53 genotype-diabetes effects were detected for fasting plasma glucose. In particular, in the diabetic subjects, Pro/Pro genotype was associated with lower values of HOMA-IR with respect to Arg/Arg (p = 0.013) and Arg/Pro (p = 0.006) carriers. No difference in HOMA-IR between diabetic and non-diabetic Pro/Pro carriers was found. Significant recessive model-diabetes interaction effects on fasting insulin and HOMA-IR adjusted for age, sex and BMI were found (p = 0.007 and p = 0.029, respectively). Linear regression analyses, based on the assumption of an additive genetic model adjusted for age, sex and BMI, highlight p53 gene-diabetes interaction effects on fasting insulin (β = -1.27; p = 0.001) and HOMA-IR (β = -0.22; p = 0.006). The results of statistical analyses on fasting insulin and HOMA-IR were all confirmed in the validation sample. Furthermore, the logistic regression models confirmed that the effect of HOMA-IR levels on diabetes was moderated by Pro/Pro genotype in both study and validation samples (OR = 0.29, p = 0.034, 95 % CI = 0.09-0.91, OR = 0.37, p = 0.035, 95 % CI = 0.15-0.93, respectively). Our findings suggest that p53 codon 72 (Arg72Pro) polymorphism influences insulin resistance in type 2 diabetic patients independently of body mass.

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Our work demonstrates that rs805304 DDAH2-1151 polymorphism plays a central role in determining ADMA in diabetic renal impairment, where patients with DDAH2-1151 C carriers showed the highest ADMA levels. This unfavourable genetic profile is highlighted by pathological kidney conditions such as diabetic CRF. These findings could open new insights on the pathways involving ADMA/DDAH/NOS in the development and progression of chronic renal impairment and therefore of the other micro- macrovascular diabetic complications.

BackgroundPhysical activity (PA) has health benefits for people with type 2 diabetes (T2D). Indeed, regular PA is considered an important part of any T2D management plan, yet most patients adopt a sedentary lifestyle.Exercise referral schemes (ERS) have the potential to effectively promote physical activity among T2D patients, and their effectiveness may be enhanced when they are supported by computer-based technologies.The ‘TRIPL-A’ study (i.e., a TRIal to promote PhysicaL Activity among patients in the young-old age affected by T2D) aims to assess if realizing an innovative ERS, based on a strong partnership among general practitioners, specialist physicians, exercise specialists, and patients, and supported by a web-based application (WBA), can effectively lead sedentary older T2D patients to adopt an active lifestyle.MethodsA randomized controlled design will be used, and an ERS, supported by a WBA, will be implemented. 300 physically inactive T2D patients (aged 65–74 years) will be assigned to either an intervention or control arm. Control arm patients will only receive behavioral counseling on physical activity and diet, while intervention arm patients will also undergo an 18-month (3 day/week), discontinuously supervised aerobic exercise training program. The trial will be divided into six three-month periods: during first, third and fifth period, an exercise specialist will supervise the training sessions and, using the WBA, prescribe exercise progression and monitor exercise adherence. Patients will exercise on their own in the other periods.Patients’ sedentary behaviors (primary outcome), PA level, fitness status, metabolic profile, psychological well-being, quality of life, and use of health care services (secondary outcomes) will be assessed at baseline and at 6, 12, and 18 months from baseline.Repeated measure ANCOVAs will be used to compare the intervention and control arm with respect to each study outcome measure.DiscussionPrimary and secondary outcome results will allow us to evaluate the effectiveness of an ERS, specifically designed for the management of T2D clinical conditions and supported by a WBA, in promoting PA within Italian primary care settings.Trial registrationThis trial is retrospectively registered under the Australian New Zealand Clinical Trials Registry (reference number: ACTRN12618001164280; registered 13 July 2018).