Factors affecting obesity and its treatment

Adipose tissue plays an important role in energy homeostasis by secreting different hormones and peptides which regulate whole body metabolism. Lower or higher level secretion of adipokines leads to obesity and many other diseases. Moreover, inflammation in adipose tissue of obese people leads to insulin resistance, therefore causing obesity. Inflammatory cytokines emerge as a key player in the progression of obesity. In addition to obesity, many other factors are also responsible for insulin resistance. Investigations conducted over the past decade have revealed a great deal about how inflammation in adipose tissue responsible for the development of insulin resistance. Many drugs have a dramatic effect on insulin resistance like Thiazolidinediones (TZDs) which shows anti-inflammatory effect as it activates Peroxisome proliferator-activated receptor gamma (PPARγ). PPARγ have a significant impact on insulin sensitivity. Along with obesity many other factors also involve in insulin resistance like mitochondrial dysfunction, endoplasmic stress, oxidative stress, etc. Insulin resistance is considered to be the main cause of Diabetes-2. Treatment for obesity is limited because of the side effects of conventional drugs. Inflammatory cytokines like TNF-α, IL-6 also have a significant impact on gut microbiota and IL-15 participates in insulin resistance and in their beneficial activities. Enhanced level of inflammatory cytokine due to obesity also responsible for the polycystic ovary syndrome (PCOS), therefore PCOS also associates to the obesity. It was also found that in visceral adipose tissue of the PCOS patient, reduced form of β subunit of insulin receptor was found. Therefore, in this review we will also discuss how insulin and inflammatory cytokines involve in PCOS. There is a growing interest to enhance remodeling of white fats into brown as a strategy to fight obesity and diabetes; it may be beneficial to overcome obesity as well as insulin resistance. Consequently, in this review, we have explored the different pathways which linked to insulin resistance and try to catch a glimpse how a drug acts to control insulin resistance and its mechanism of action.