Intestinal barrier dysfunction is hypothesized to be a contributing determinant of two prominent characteristics of aging: inflammation and decline in physical function. A relationship between microbial translocation (MT), or their biomarkers (lipopolysaccharide binding protein-1 [LBP-1], soluble cluster of differentiation [sCD]-14), and physical function has been reported in healthy older adults, rats, and invertebrates. However, it is not known whether the existence of comorbidities, or clinical interventions intended to reduce comorbidities through weight loss or exercise, alters this connection. We measured inflammation, MT, and physical function in 288 overweight/obese older patients with cardiometabolic disease and self-reported mobility limitations who were enrolled in a weight loss and lifestyle intervention study. At baseline, inflammatory cytokines and LBP-1 were positively correlated after adjustment for age, gender, and body mass index. A higher LBP-1 was significantly associated with poorer physical functional after covariate adjustment. Further, even when IL-6 levels were included in the models, 400-m walk time (p = 0.003), short physical performance battery (p = 0.07), and IL-8 (p < 0.001) remained positively associated with LBP-1. Lifestyle interventions improved body mass and some functional measures; however, MT and inflammation were unchanged. MT is reliably related to inflammation, and to poorer physical function in older adults with comorbid conditions. Intestinal barrier function did not appear to improve as a result of intervention assignment, suggesting alternative strategies are needed to target this pro-inflammatory pathway in aging.
Keywords: Ageing; Lipopolysaccharide-binding protein; Microbial translocation; Physical function.