The Role of Thiosulfate Sulfurtransferase in Oxidative Stress for Type 2 Diabetes Mellitus

BACKGROUND: Type 2 diabetes mellitus (T2DM) is associated with oxidative stress, leading to insulin resistance. Thiosulfate sulfurtransferase (TST) is mitochondrial enzyme involved in the reaction with cyanide, endogenous hydrogen sulfide (H₂S), and reactive oxygen species. AIM: This study aimed to investigate the relationship between TST enzyme and both oxidative and anti-oxidative stress markers in T2DM patients. TST is believed to be related to oxidative stress, which plays a crucial role in determining the severity and progression of the disease. MATERIALS AND METHODS : A case-control study included (150) T2DM patients who were taking the drug Metformin (Glucophage) 500 mg twice daily as well as (150) healthy subjects aged between 33 to 65 years. TST activity was estimated based on the sulfur transfer and thiocyanate formation. Malonaldehyde (MDA), peroxynitrite, peroxidase, aryl esterase, vitamin C, vitamin E, thioredoxin (Trx) and glutathione (GSH) were also measured. In addition to clinical markers, all measurements were made in two replicates, statistical analyses were conducted, and data were presented as a median and interquartile range. RESULTS: TST activity was significantly lower (by 55%) in T2DM patients compared to the controls (8.5 (3.8) vs. 19 (2) U/ml, respectively). There was an inverse relationship between enzyme activity and age, whereas enzyme activity increased with smoking. Antioxidant compounds such as vitamin C, vitamin E, GSH, Trx, and arylesterase activity were significantly lower, while oxidant markers including peroxidase activity, MDA, and peroxynitrite, were significantly higher. TST activity showed a negative correlation with MDA and peroxynitrite, and a positive correlation with Trx and GSH. CONCLUSION: TST activity is reduced in T2DM patients and is associated with oxidative stress. This suggest that TST may play a protective role against oxidative stress, making it a potential indicator of metabolic regulation and a possible therapeutic target.