Insulin resistance appears to be directly associated with oxidative stress and TNF-α levels in rheumatoid arthritis (RA) patients, according to a study conducted by Brazilian scientists.
The study suggests that insulin resistance could be a reason why TNF-α inhibitors sometimes are not effective in treating people with RA, though additional research is still needed to confirm the findings.
The study, “Influence of Insulin Resistance and TNF-α on the Inflammatory Process, Oxidative Stress, and Disease Activity in Patients with Rheumatoid Arthritis,” was published in the research journal Oxidative Medicine and Cellular Longevity.
TNF-α is a cell-signaling molecule that plays a major role in regulating inflammation. In RA, TNF-α is produced excessively and causes damage to the joints, which makes TNF-α inhibitors important for RA treatment.
In order to evaluate the involvement of TNF-α and insulin resistance in the inflammatory process, oxidative stress, and disease activity in patients with RA, the team of scientists analyzed 173 RA patients. They divided them into four varying groups:
- Those without insulin resistance and not using TNF-α inhibitors.
- Those without insulin resistance and using TNF-α inhibitors
- Those with insulin resistance and not using TNF-α inhibitors
- Those with insulin resistance and using TNF-α inhibitors
Researchers then compared oxidation protein products and oxidative stress indexes of the different groups as an indication of oxidative stress, which is an imbalance between the production of free radicals and the ability of the body to counteract or detoxify their harmful effects through neutralization by antioxidants.
The researchers found that oxidative stress levels were higher in RA patients in group 3 and group 4, compared to patients in group 1, and that oxidative stress levels were higher in RA patients in group 4 compared to those in group 2.
Finally, they reported that levels of TNF-α were significantly higher in the blood of patients in group 4 and group 2 compared to those in group 1 and group 3. The researchers concluded that insulin resistance is highly associated with oxidative stress and TNF-α levels in the blood.
Analyzing the differences in oxidative stress markers in RA patients could help design future studies looking at the effect of drugs and, or nutritional interventions in RA.