Obesity and diabetes: from genetics to epigenetics

Abstract

Obesity is becoming an epidemic health problem. During the last years not only genetic but also, and primarily, environmental factors have been supposed to contribute to the susceptibility to weight gain or to develop complications such as type 2 diabetes. In spite of the intense efforts to identify genetic predisposing variants, progress has been slow and success limited, and the common obesity susceptibility variants identified only explains a small part of the individual variation in risk. Moreover, there is evidence that the current epidemic of obesity and diabetes is environment-driven. Recent studies indicate that normal metabolic regulation during adulthood besides requiring a good balance between energy intake and energy expenditure, can be also affected by pre- and post-natal environments. In fact, maternal nutritional constraint during pregnancy can alter the metabolic phenotype of the offspring by means of epigenetic regulation of specific genes, and this can be passed to the next generations. Studies focused on epigenetic marks in obesity found altered methylation and/or histone acetylation levels in genes involved in specific but also in more general metabolic processes. Recent researches point out the continuous increase of "obesogens", in the environment and food chains, above all endocrine disruptors, chemicals that interfere with many homeostatic mechanisms. Taken into account the already existing data on the effects of obesogens, and the multiple potential targets with which they might interfere daily, it seems likely that the exposure to obesogens can have an important role in the obesity and diabesity pandemic.

Acanthosis nigricans in obese adolescents: prevalence, impact, and management challenges

“…T2DM was considered a disease of the elderly in the last century, whereas it is increasingly common to encounter T2DM in adolescents today 96. T2DM in childhood is often asymptomatic for a period of time.…”

Exploring Complexities of T2DM: Insulin Signaling, Resistance and Deficiency, Metabolic Links, Sexual Dimorphism and Endocrine Disruptors

“…While lifestyle factors and genetic susceptibility are well-known factors, there is accumulating evidence that the current epidemic of obesity and diabetes is environment-driven and endocrine disrupting chemicals (EDCs) are involved in the pathogenesis. Further, there has been a continuous increase of EDCs and 'obesogens' in the environment and food chains and various obesogens identified so far, appear to have a significant role in the obesity and diabesity pandemic [40]. An ample evidence, both from in vivo and in vitro experimental and epidemiological studies support the hypothesis that exposure to EDCs is related to the current pandemic of T2DM.…”

Epigenetics, Media Coverage, and Parent Responsibilities in the Post-Genomic Era

“…By emphasizing the effect of socioeconomic and political events such as trauma, famine, and care on individuals and their genetic lineage, these studies offer a way of tracing how experiences get “under the skin” and their influences across multiple generations [19]. To date, epigenetic modifications have been linked to numerous outcomes including obesity and diabetes [20], cancer [21], heart disease [22], depression [23], anxiety [24, 25], and autism [26], among others. These findings reveal the growing influence of epigenetic research for both public and professional understandings of health and disease, and the important role that various sectors of society can play in shaping our interpretations of this science.…”