Simple resistance exercise decreases cytokeratin 18 and fibroblast growth factor 21 levels in patients with nonalcoholic fatty liver disease A retrospective clinical study

Cytokeratin 18 (CK18) and fibroblast growth factor 21 (FGF21) are elevated in patients with nonalcoholic fatty liver disease (NAFLD) and are useful markers for identifying or monitoring outcomes. Exercise therapy is one of the established treatments for NAFLD; however, few studies have investigated the effectiveness of exercise therapy on CK18 and FGF21 levels. Therefore, the aim of the present study was to assess the effects of 12 weeks of simple resistance exercise on CK18 and FGF21 levels in patients with NAFLD. Fifty patients with NAFLD were assigned to a resistance exercise group (n = 23) or a control group (n = 27) for a trial period of 12 weeks. During the study, the resistance exercise group performed two exercises (push-ups and squats) three times a week on nonconsecutive days, whereas the control group proceeded with regular physical activities under a restricted diet. We then compared serum levels of CK18 fragments (M65) and FGF21 between groups just before and after the 12-week period. Serum M65 levels (880.0 +/- 503.6 vs 648.9 +/- 450.2 U/L;P < .01) were significantly decreased in the exercise group. However, no significant differences were observed in body mass index or skeletal muscle. The decreases in serum M65 (-231.1 +/- 354.7 vs 56.2 +/- 375.0 U/L;P = .02), and FGF21 levels (-41.7 +/- 98.2 vs. 33.2 +/- 127.6 pg/mL;P = .03) were significantly greater in the exercise than in the control group. Changes in M65 levels in the exercise group were significantly correlated with changes in alanine aminotransferase levels (r = 0.618,P < .01). Simple resistance exercise reduced CK18 and FGF21 levels in patients with NAFLD. These findings suggest that resistance exercise consisting of push-ups and squats helps prevent the progression of NAFLD.