Do Intestinal Unicellular Parasites Have a Role in the Inflammatory and Redox Status among the Severely Obese?

The diagnosis of obesity comprises subjects with totally different phenotypes and metabolic profiles. Systemic inflammation and oxidative stress derived from the white adipose tissue are suggested as the link between this disease and the development of insulin resistance and metabolic comorbidities. The presence of unicellular eukaryotic parasites colonizing the human gut ecosystem is a common circumstance, and yet their influence on the inflammatory and redox status of the obese host has not been assessed. Herein, a set of inflammatory and redox biomarkers were assessed together with a parasitological analysis of 97 severely obese subjects. Information was also collected on insulin resistance and on the antioxidant composition of the diet. The global prevalence of intestinal unicellular parasites was 49.5%, with Blastocystis sp. the most prevalent protozoan found (42.3%). Colonized subjects displayed a higher total antioxidant capacity and a trend towards higher extracellular superoxide dismutase activity, regardless of their insulin resistance status, along with lower reduced glutathione/oxidized glutathione (GSH/GSSG) ratios in plasma in the insulin-resistant subgroup. No changes in malondialdehyde levels, or in inflammatory cytokines in plasma, were found in regard to the colonization status. In conclusion, enteric eukaryotic unicellular parasites may play an important role in modulating the antioxidant defenses of an obese host, thus could have beneficial effects with respect to the development of systemic metabolic disorders.