High-intensity interval training modulates retinal microvascular phenotype and DNA methylation of p66Shc gene: a randomized controlled trial (EXAMIN AGE).

AIMS: Impairments of retinal vessel diameter are associated with major adverse cardiovascular (CV) events. Promoter DNA methylation is a repressor of the mitochondrial adaptor p66Shc gene transcription, a key driver of ageing-induced reactive oxygen species. The study aimed to investigate whether high-intensity interval training (HIIT) affects retinal microvascular phenotype as well as p66Shc expression and oxidative stress in ageing subjects with increased CV risk from the EXAMIN AGE cohort. METHODS AND RESULTS: Eighty-four sedentary subjects (mean age 59.4 ± 7.0 years) with ≥2 CV risk factors were randomized into either a 12-week HIIT or standard physical activity recommendations. Retinal arteriolar and venular diameters were measured by use of a retinal vessel analyser. As a marker of oxidative stress plasma 3-nitrotyrosine (3-NT) level was determined by ELISA. Gene expression of p66Shc and DNA methylation were assessed in mononuclear cells by RT-qPCR and methylated-DNA capture (MethylMiner Enrichment Kit) coupled with qPCR, respectively. High-intensity interval training reduced body mass index, fat mass, low-density lipoprotein and increased muscle mass, as well as maximal oxygen uptake (VO2max). Moreover, HIIT restored microvascular phenotype by inducing retinal arteriolar widening (pre: 175 ± 14 µm vs. post: 181 ± 13 µm, P = 0.001) and venular narrowing (pre: 222 ± 14 µm vs. post: 220 ± 14 µm, P = 0.007). After HIIT, restoration of p66Shc promoter methylation (P = 0.034) reduced p66Shc gene expression (P = 0.037) and, in turn, blunted 3-NT plasma levels (P = 0.002). CONCLUSION: High-intensity interval training rescues microvascular dysfunction in ageing subjects at increased CV risk. Exercise-induced reprogramming of DNA methylation of p66Shc gene may represent a putative mechanistic link whereby exercise protects against age-related oxidative stress. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02796976 (https://clinicaltrials.gov/ct2/show/NCT02796976).

Gender-dependent resiliency to stressful and metabolic challenges following prenatal exposure to high-fat diet in the p66(Shc-/-) mouse.

Metabolic stressful challenges during susceptible time windows, such as fetal life, can have important implications for health throughout life. Deletion of the p66(Shc) gene in mice leads to reduced oxidative stress (OS), resulting in a healthy and lean phenotype characterized by increased metabolic rate, resistance to high-fat diet (HFD)-induced obesity and reduced emotionality at adulthood. Here we hypothesize that p66(Shc-/-) (KO) adult offspring might be protected from the detrimental effects induced by maternal HFD administered before and during pregnancy. To test such hypothesis, we fed p66(Shc+/+) (WT) and KO females with HFD for 13 weeks starting on 5 weeks of age until delivery and tested adult male and female offspring for their metabolic, neuroendocrine, and emotional profile. Prenatal diet affected stress responses and metabolic features in a gender-dependent fashion. In particular, prenatal HFD increased plasma leptin levels and decreased anxiety-like behavior in females, while increasing body weight, particularly in KO subjects. KO mice were overall characterized by metabolic resiliency, showing a blunted change in glycemia levels in response to glucose or insulin challenges. However, in p66(Shc-/-) mice, prenatal HFD affected glucose tolerance response in an opposite manner in the two genders, overriding the resilience in males and exacerbating it in females. Finally, KO females were protected from the disrupting effect of prenatal HFD on neuroendocrine response. These findings indicate that prenatal HFD alters the emotional profile and metabolic functionality of the adult individual in a gender-dependent fashion and suggest that exposure to high-caloric food during fetal life is a stressful condition interfering with the developmental programming of the adult phenotype. Deletion of the p66(Shc) gene attenuates such effects, acting as a protective factor.