Low macrophage accumulation in skeletal muscle of obese type 2 diabetics and elderly subjects

CS Tam, LM Sparks, DL Johannsen, JD Covington… - …, 2012 - Wiley Online Library
CS Tam, LM Sparks, DL Johannsen, JD Covington, TS Church, E Ravussin
Obesity, 2012Wiley Online Library
In addition to adipose tissue, recent studies suggest that skeletal muscle may also be a
source of low‐grade inflammation, particularly in inactive and/or overweight individuals. The
aim of this study was to examine the presence of macrophages in skeletal muscle from
obese subjects with type 2 diabetes (T2D) before and after a 9‐month exercise program (vs.
a non‐exercising control group)(Study 1) and in young vs. elderly subjects (Study 2). In both
studies, CD68+ macrophages in vastus lateralis biopsies were determined by …
In addition to adipose tissue, recent studies suggest that skeletal muscle may also be a source of low‐grade inflammation, particularly in inactive and/or overweight individuals. The aim of this study was to examine the presence of macrophages in skeletal muscle from obese subjects with type 2 diabetes (T2D) before and after a 9‐month exercise program (vs. a non‐exercising control group) (Study 1) and in young vs. elderly subjects (Study 2). In both studies, CD68+ macrophages in vastus lateralis biopsies were determined by immunohistochemistry and inflammation gene expression measured. Macrophage content (%) was calculated by the number of macrophages per 100 muscle fibers. In Study 1, we found relatively low numbers (2–3%) of CD68+ macrophages in skeletal muscle in obese T2D subjects (BMI = 37.3 ± 5.2 kg/m2), which were unchanged after a 9‐month exercise program (P = 0.42). Similarly, in Study 2 (BMI = 27.1 ± 2.5 kg/m2), CD68+ macrophages were relatively low in muscle (4–5%) and were not different between young and elderly individuals (P = 0.42). However, elderly subjects had twofold higher CD68 and CD206 gene expression (both P < 0.002) than young participants. In both studies, CD68+ muscle macrophages were not associated with BMI. In conclusion, we found little evidence of macrophage accumulation in skeletal muscle in obese T2D subjects or in elderly individuals. A 9‐month exercise program was not associated with a decrease in macrophage content.
Wiley Online Library