Mild Renal Dysfunction and Metabolites Tied to Low HDL Cholesterol are Associated with Monocytosis and Atherosclerosis
Background—The number of circulating blood monocytes impacts atherosclerotic lesion size and in mouse models, elevated levels of high density lipoprotein-cholesterol (HDL-C) suppress blood monocyte counts and atherosclerosis. We hypothesized that individuals with mild renal dysfunction at increased cardiovascular risk would have reduced HDL levels, high blood monocyte counts, and accelerated atherosclerosis.
Methods and Results—To test whether mild renal dysfunction is associated with increase in a leukocyte subpopulation rich in monocytes that has a known association with future coronary events, we divided individuals from the Malmö Diet and Cancer study (MDC) into baseline cystatin C quintiles (N=4757). Lower levels of renal function were accompanied by higher monocyte counts, and monocytes were independently associated with carotid bulb intima-media thickness cross-sectionally (p= 0.02). Cystatin C levels were positively and plasma HDL-C levels negatively associated with monocyte counts at baseline, following adjustment for traditional risk factors. Several amino acid metabolites tied to low HDL-C and insulin resistance measured in a subset of individuals (N= 752) using liquid chromatography-mass spectrometry were independently associated with a 22-34% increased risk of being in the top quartile of monocytes (p<0.05).
Conclusions—A low HDL-C, insulin resistance phenotype occurs in subjects with mild renal dysfunction and is associated with elevated monocytes and atherosclerosis. High blood monocytes may represent a previously unrecognized mechanism underlying the strong relationship between cystatin C and cardiovascular risk.
- Received December 14, 2012.
- Revision received January 18, 2013.
- Accepted January 22, 2013.
- Copyright © 2013, Circulation