Adiponectin in Diabetic Subjects Without Any Micro- or Macrovascular Complications

Adipose tissue is an important endocrine organ responsible for the secretion of adipokines, which play important roles in glucose and lipid homeostasis. Type 2 diabetes (T2D) has been proven as a major result from fat accumulation thus leading to insulin insensitivity. This adipose specific secreted protein has important inflammatory properties that are present in the circulation and involved in the regulation of insulin sensitivity, ¹ thus making it an important modulator for T2D. The main purpose of this article is to understand the levels of adiponectin for diabetic subjects without any complications and its necessity for managing obesity.

In a recent published article, ² a cross-sectional study of 229 cases of T2D and 205 healthy individuals of age 30-70 years was presented from the Dakshina Kannada district of Karnataka, India. Clinical examinations were done for the assessment of cardiovascular and abdominal system. Estimations of adiponectin levels were done using ELISA technique. Anthropometric variables were measured by standard procedure and HbA1c tested via immunoturbidometry. The results obtained were analyzed using SPSS 10.0, Student’s unpaired t test. Pearson correlation was analyzed between the parameters of the study population.

The results showed the mean value of adiponectin of the diabetic study population was significantly less (15.98 + 6.02) when compared to normal subjects (18.14 + 8.32). An increase in the values for the nondiabetic population was seen in both female and male groups (P = .008). Negative correlations were observed between glycated hemoglobin and adiponectin in the diabetic group (P = –.361) and for body mass index (BMI) compared with adiponectin in normal group (P = −0.302). In addition, males in normal population had higher adiponectin levels than female but showed the opposite in the diabetic group as males in the diabetic had lower than females.

With the use of observational research methods to determine the validity of this study, we relate to prospective studies showing how the levels of adiponectin have been supported as being lower in diabetic subjects^2,3 when compared to normal as a good glycemic index in diabetic subjects helps to increase the levels of adiponectin.

Though an inverse relation was observed between BMI and adiponectin in healthy individuals, the relation was lost in obese diabetic subjects free from micro- or macrovascular complications. Studies have produced negative correlations; however, they are inconsistently inversely correlated with BMI.^1,3,4 Studies have also shown plasma adiponectin levels being negatively regulated by adiposity. ⁵

Obese subjects express significantly lower levels of adiponectin in nondiabetic patients, and a strong correlation between adiponectin and systemic insulin sensitivity has been well established both in vivo and in vitro, in mice, other animals, and humans. A rise in adiponectin levels showed weight loss and across diverse populations from 13 prospective studies are associated with a lower risk of T2D. ⁵ However adiponectin’s potential remains substantially weak since adiponectin is independent of obesity in diabetic patients from these studies. This very important adipocytokine is abundant, and it has important applications, but if it is to act as a marker for adiposity, more research is needed to support the value bounding this theory.

The benefit of this study design allowed researchers to compare many different variables at the same time. The study also showed reproducibility as the measurements used were regarded as valid by other investigators. The quality of measurements and outcomes was controlled, and since all the patients were accounted for the study statistically showed completeness.

However, longitudinal studies are required for a more definite understanding of cause and effect for clinical applications of adiponectin. From recent studies high serum adiponectin concentration and low BMI are significantly associated with the mortality in an elderly cohort of all cause and cardiovascular disease. ⁶ Adiponectin administration also shows a promising pathway for managing obesity clinically; however, it remains to be determined whether adiponectin can be used effectively and safely as pharmacologic means to treat obesity in humans whether through pharmaceutical or lifestyle interventions.

T2D in the world has reached epidemic proportions, and replenishment of adiponectin might represent a novel treatment for insulin resistance (IR) and T2D since it appears to be an important modulator. Future studies should therefore evaluate adiponectin as it is a target for the reduction of T2D. With the global increase in the incidence of diabetes, new strategies to prevent the complications are urgently needed.