PINK1 and oxidative stress in lean and obese patients with type 2 diabetes mellitus

To compare mRNA [messenger RNA] expression of PINK1 in whole blood and the levels of biomarkers of Oxidative Stress (mitochondrial DNA [mtDNA] content & Total Antioxidant status [TAS]) in newly diagnosed lean and obese patients with T2DM.

Newly diagnosed patients of T2DM were enrolled in this study. The patients were divided into two groups of 30 patients each, lean (BMI < 18.5 kg/m²) and obese (BMI > 25 kg/m²). mRNA expression of PINK1 & mtDNA content was measured by real time PCR. Serum TAS was measured using a commercially available kit.

There was a 1.78-fold decrease in mRNA expression of PINK1 in obese group compared to the lean group. Mean mtDNA content was 300.82 ± 169.66 in the obese group and 332.78 ± 147.07 in the lean group (p = 0.06). Mean levels of TAS was 5.39 ± 2.28 μM Trolox Equivalents in the obese group and 3.85 ± 3.33 μM Trolox Equivalents in the lean group (p = 0.001).

The T2DM patient with obesity had greater OS than the lean patients. Thus, there is a compensatory increase in antioxidants in obese patients with T2DM. Our findings also suggest that decreased levels of PINK1 in obese group are unable to protect the mitochondria against OS leading to decreased mtDNA content. Does it also result in beta cell dysfunction or contribute to insulin resistance in obese patients with T2DM needs to be explored.