Serum PCSK9 levels in infants with deviant birth weight: a biomarker of the lipoprotein metabolism

Objective Proprotein Convertase Subtilisin/Kexin-Type 9 (PCSK9), a modulator of low-density lipoprotein (LDL) cholesterol metabolism, has been reported to be a promising biomarker for evaluating lipoprotein metabolism; however, evidence in infants is limited. In the current study, we sought to investigate potential differences in serum PCSK9 levels between infants with deviant birth weight and controls. Methods We enrolled 82 infants, classified into 33 small (SGA), 32 appropriate (AGA), and 17 large for gestation (LGA) infants. Serum PCSK9 was measured on routine blood analysis within the first postnatal 48 h. Results PCSK9 was significantly higher in SGA as compared to AGA and LGA infants [322 (236-431) as compared to 263 (217-302) and 218 (194-291) ng/ml respectively, p = .011]. In comparison to term AGA infants, PCSK9 was significantly elevated in preterm AGA and SGA infants. We also found a significantly higher level of PCSK9 in term female SGA infants as compared to term male SGA infants [325 (293-377) as compared to 174 (163-216) ng/ml, p = .011]. PCSK9 was significantly correlated with gestational age (R = -0.404, p < .001), birth weight (R = -0.419, p < .001), total cholesterol (R = 0.248, p = .028) and LDL cholesterol (R = 0.370, p = .001). SGA status (OR 2.56, p = .004, 95% CI 1.83-4.28) and prematurity (OR 3.10, p = .001, 95% CI 1.39-4.82) were strongly related to serum PCSK9 levels. Conclusion PCSK9 levels were significantly associated with total and LDL cholesterol. Moreover, PCSK9 levels were higher in preterm and SGA infants, suggesting that PCSK9 might be a promising biomarker for evaluating infants with increased later cardiovascular risk.