Severely Obese Have Greater LPS-stimulated TNF-α Production Than Normal Weight African-American Women

Obesity is associated with an increase in chronic, low-grade inflammation which has been implicated in the development of type 2 diabetes mellitus and cardiovascular disease. The purpose of this study was to determine whether obesity was associated with an elevation of whole blood lipopolysaccharide (LPS)-stimulated tumor necrosis factor-alpha (TNF-alpha) production. African-American women were recruited from a larger study and assigned to one of five groups based on BMI: normal weight (NORM; BMI 20-25, n = 7), overweight (OVER; BMI 25-30, n = 12), class 1 obese (OB1; BMI 30-35, n = 19), class 2 obese (OB2; BMI 35-40, n = 10), or class 3 obese (OB3; BMI >40, n = 17). Body composition was determined via a whole body dual-energy X-ray absorptiometry (DXA) scan. Venous blood samples were collected following an overnight fast (>8h), and stimulated with five doses of LPS (Salmonella enteriditis): 80, 40, 20, 10, and 5 mu g/ml for 24 h in a 37 degrees C, 5% CO2 incubator. Following stimulation, TNF-alpha was measured using enzyme-linked immunosorbent assay. OB3 produced 365% more TNF-alpha than NORM at an LPS dose of 20 mu g/ml (P < 0.05). When maximal TNF-alpha production was assessed regardless of LPS dose, OB3 produced 230% more than NORM and OVER produced 190% more than NW (P = 0.001). Total and trunk fat mass and BMI were significantly correlated with maximal TNF-alpha production and LPS = 20 mu g/ml. Our findings are consistent with previous reports suggesting a relationship between increased adiposity and inflammatory marker production. This is one of the first studies to focus on African-American women, who have higher rates of obesity.