Role of NLRP3 inflammasome and oxidative stress in hepatic insulin resistance and the ameliorative effect of phytochemical intervention

NLRP3 inflammasome has a key role in chronic low-grade metabolic inflammation, and its excessive activation may contribute to the beginning and progression of several diseases, including hepatic insulin resistance (hIR). Thus, this review aims to highlight the role of NLRP3 inflammasome and oxidative stress in the development of hIR and evidence related to phytochemical intervention in this context. In this review, we will address the hIR pathogenesis related to reactive oxygen species (ROS) production mechanisms, involving oxidized mitochondrial DNA (ox-mtDNA) and thioredoxin interacting protein (TXNIP) induction in the NLRP3 inflammasome activation. Moreover, we discuss the inhibitory effect of bioactive compounds on the insulin signaling pathway, and the role of microRNAs (miRNAs) in the phytochemical target mechanism in ameliorating hIR. Although most of the research in the field has been focused on evaluating the inhibitory effect of phytochemicals on the NLRP3 inflammasome pathway, further investigation and clinical studies are required to provide insights into the mechanisms of action, and, thus, encourage the use of these bioactive compounds as an additional therapeutic strategy to improve hIR and correlated conditions.

Baseline Diet Quality Is Related to Changes in the Body Composition and Inflammatory Markers: An Intervention Study Based on Resistance Training and Nutritional Advice

Habitual food intake and physical activity can affect chronic low-grade inflammation, which is common in the elderly, because of changes in the immune system and body composition. Thus, the present study proposes an evaluation of the influence of past eating habits on the effects of an intervention of resistance training plus dietary advice on the inflammatory profile of the elderly. We conducted an intervention study with 40 elderly people. The Revised Diet Quality Index (HEI-R) and the dietary total antioxidant capacity (dTAC) were calculated before the intervention based on a food frequency questionnaire validated to the elderly population. Participants were categorized according to the median of HEI-R and dTAC to assess the influence of the habitual diet quality on anthropometry and inflammatory markers (CRP, IL-8, CCL-2, and leptin) before and after the intervention. The 19-week intervention provided a long-term progressive resistance training associated with dietary advice focused on foods rich in compounds with anti-inflammatory and antioxidant properties. There was a greater reduction in weight, body mass index (BMI), and body fat (%) in the group with the lowest HEI-R and a greater reduction in the body fat (%) in the group with the lowest dTAC, indicating that the group that had a worse diet quality before the intervention responded better to it. The index HEI-R correlated negatively with Δweight and ΔBMI. dTAC correlated positively with Δmonocyte 1 chemotactic protein (CCL-2) and ΔC-reactive protein (CRP). In this scenario, elderly persons with bad habits can benefit from interventions to lifestyle change, while the better diet quality including dietary antioxidant sources can be useful to control weight and inflammatory biomarkers in this population.