Type 2 Diabetes and Obesity: Adipokines the molecular link

Joyita Banerjee, (SIU-JRF)

Type 2 Diabetes mellitus (T2DM) and obesity have become emerging health challenges in the developed and developing nations. T2DM and obesity both are the growing problems in India. According to the International Federation of Diabetes, that India will become a home for 109 million of diabetic people by 2035 from 65.1 million in 2013. India ranks second among the top ten countries with diabetes. Rapid urbanization, sedentary life style, and high calorie junk food induce excessive accumulation of lipid in adipose and peripheral tissues, which eventually has increased the prevalence of obesity. It has been found that women are more prone to obesity than men. According to a report published in the journal The Lancet there were 20 million obese women as compared to 9.8 million obese men in India in 2014. It has been observed that obese people are more prone to develop T2DM. Last decade has experienced extensive researches in linking obesity with T2DM by different factors such as, insulin resistance, abdominal fat, free fatty acids, triglycerides, adipokines, genetic and environmental factors.

Recent studies have explored various possible molecular mechanisms centring adipokines for the probable missing link between obesity and T2DM. These adipokines are the cytokines that is, cell signalling proteins released from the adipose or fat tissues of the body. There are several adipokines discovered so far, of which, adiponectin, leptin, resistin, vaspin, apelin, visfatin, chemerin, tumor necrosis factor-alpha (TNF-α) have significant correlation with body mass index (BMI) and insulin resistance. These adipokines are known to have potential role in inflammation (pro-inflammatory and anti-inflammatory) and insulin resistance. The higher expression of pro-inflammatory adipokines has been observed in obese individuals which ultimately induces insulin resistance.

The researchers of Indian Institute of Chemical Biology, Kolkata, recently reported about chemerin, an adipokine which is released from the fat cells of the obese people. This study has opened up novel therapeutic opportunities against obesity and T2DM. The chemerin recruits specific immune cells into visceral adipose tissue and through down-stream signaling pathway drives the macrophages (innate immune system cells). These macrophages in turn induce inflammation. This study was published in the journal Diabetes in August 2016. Another adipokine to mention about is adiponectin that can be considered as innovative biomarkers for the screening, diagnosis and therapeutic monitoring of T2DM in the obese, insulin-resistant individuals and diabetic patients.

Thus, further knowledge of the underpinnings of adipose tissue dysfunction, adipokines may provide new targets for drug development for the management of obesity and prevention of T2DM. The higher prevalence of T2DM and obesity has directly elevated the risk of various cardiovascular complications in India. There is an urgent call for early interventions to control these metabolic disorders and to restrain them from becoming epidemic.