Reduction of DNA damage in peripheral lymphocytes of obese patients after bariatric surgery-mediated weight loss

Obesity is associated with several detrimental health consequences, among them an increased risk for development of cancer, and an overall elevated mortality. Multiple factors like hyperinsulinemia, chronic microinflammation and oxidative stress may be involved. The comet assay has been proven to be very sensitive for detection of DNA damage and has been used to explore the relationship between overweight/obesity and DNA damage, but results are controversial. Very few investigations have been performed to correlate weight loss of obese individuals and possible reduction of DNA damage and these studies have not provided clear results. As currently, only surgical interventions (metabolic/bariatric surgery) enable substantial and sustained weight loss in the vast majority of morbidly obese patients, we analyzed whole blood samples of 56 subsequent patients prior, 6 and 12 months after bariatric surgery. No reduction of DNA damage was observed in comet assay analysis after 6 months despite efficient weight loss, but a significant reduction was observed 12 months after surgery. Concurrently, the ferric-reducing antioxidant power assay showed a significant reduction after 6 and 12 months. The level of oxidised glutathione and lipid peroxidation products were increased at 6 months but normalised at 12 months after surgery. As conclusion, a significant weight reduction in obese patients may help to diminish existing DNA damage besides improving many other health aspects in these patients.