Abstract
Nonalcoholic fatty liver disease (NAFLD) as the prototypic hepatic manifestation of
metabolic syndrome is an independent risk factor for cardiovascular disease. Our study
was designed to investigate the association between NAFLD and alteration in monocyte
subsets as hallmark of cardiovascular disease. Seventy-three “Echinococcus Multilocularis
and other medical diseases in Leutkirch” (EMIL) population-based cohort participants
(mean observation period 11 years) were selected to study their monocyte phenotype
by multiparameter flow cytometry. NAFLD was diagnosed using standard ultrasound based
criteria excluding other causes of fatty liver disease. Three monocyte subsets (“classical”
CD14++ CD16–, “intermediate” CD14++ CD16+, “nonclassical” CD14+CD16++ monocytes),
and surface markers (CD36 and CD9) were determined. Classical risk markers covering
inflammatory and dysmetabolic characters were also determined. Forty-three out of
73 subjects revealed a stable clinical phenotype, namely 17 subjects revealed NAFLD,
whereas 26 subjects showed no fatty liver disease. Compared to the nonfatty liver
group, the nonclassical monocyte fraction (p=0.049), total monocyte fraction and count
were increased in NAFLD probands (p=0.028, and 0.035, respectively), while classical
monocyte fraction (p=0.034) was decreased. Total monocyte fraction, nonclassical monocyte
fraction, and waist circumstance were independent risk factors for NAFLD. The nonclassical
monocyte fraction and classical monocyte fraction were significantly correlated with
waist-to-hip ratio. This pilot long-term follow-up study suggests that nonclassical
monocyte fraction and total monocyte fraction might have potential as a prognostic
and modifiable biomarker in NFALD patients. This novel marker set might therefore
be of interest to monitor druggable inflammatory pathways in individuals with hepatic
manifestation of the metabolic syndrome.
Key words
biomarker - monocyte subsets - NAFLD - metabolic syndrome - cardiovascular disease