Serum proprotein convertase subtilisin kexin type 9 is correlated directly with serum LDL cholesterol
WE Alborn, G Cao, HE Careskey, YW Qian… - Clinical …, 2007 - academic.oup.com
WE Alborn, G Cao, HE Careskey, YW Qian, DR Subramaniam, J Davies, EM Conner…
Clinical chemistry, 2007•academic.oup.comBackground: Proprotein convertase subtilisin kexin type 9 (PCSK9) is gaining attention as a
key regulator of serum LDL-cholesterol (LDLC). This novel serine protease causes the
degradation of hepatic LDL receptors by an unknown mechanism. In humans, gain-of-
function mutations in the PCSK9 gene cause a form of familial hypercholesterolemia,
whereas loss-of-function mutations result in significantly decreased LDLC and decreased
cardiovascular risk. Relatively little is known about PCSK9 in human serum. Methods: We …
key regulator of serum LDL-cholesterol (LDLC). This novel serine protease causes the
degradation of hepatic LDL receptors by an unknown mechanism. In humans, gain-of-
function mutations in the PCSK9 gene cause a form of familial hypercholesterolemia,
whereas loss-of-function mutations result in significantly decreased LDLC and decreased
cardiovascular risk. Relatively little is known about PCSK9 in human serum. Methods: We …
Abstract
Background: Proprotein convertase subtilisin kexin type 9 (PCSK9) is gaining attention as a key regulator of serum LDL-cholesterol (LDLC). This novel serine protease causes the degradation of hepatic LDL receptors by an unknown mechanism. In humans, gain-of-function mutations in the PCSK9 gene cause a form of familial hypercholesterolemia, whereas loss-of-function mutations result in significantly decreased LDLC and decreased cardiovascular risk. Relatively little is known about PCSK9 in human serum.
Methods: We used recombinant human PCSK9 protein and 2 different anti-PCSK9 monoclonal antibodies to build a sandwich ELISA. We measured PCSK9 and lipids in 55 human serum samples and correlated the results. We used the anti-PCSK9 antibodies to assay lipoprotein particle fractions separated by sequential flotation ultracentrifugation.
Results: Serum concentrations of PCSK9 ranged from 11 to 115 μg/L and were directly correlated with serum concentrations of LDLC (r = 0.45, P = 0.001) and total cholesterol (r = 0.50, P = 0.0003), but not with triglycerides (r = 0.15, P = 0.28) or HDL cholesterol concentrations (r = 0.13, P = 0.36). PCSK9 was not detectable in any lipoprotein particle fraction, including LDL.
Conclusions: PCSK9 is present in human serum, likely not associated with specific lipoprotein particles. The circulating concentrations of human PCSK9 are directly correlated with LDL and total cholesterol concentrations.
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