Abstract
Background: Increased levels of lipoprotein-associated phospholipase A(2) are associated with atherosclerosis, and may contribute to cardiac disease. The aim of this study was to analyze serum levels of lipoprotein phospholipase A(2) (Lp-PLA(2)) in patients with impaired bone resorption and correlate the findings with markers of bone metabolism (osteocalcin) and other biochemical markers (cholesterol, low density lipoprotein, triacylglycerols).
Methods: Serum Lp-PLA(2) was measured by a turbidimetric method in a group of currently treated 85 patients with impaired bone resorption and in a control group of 46 healthy individuals. Serum triacylglycerols was measured by the electrochemiluminescence immunoassay.
Cholesterol, low density lipoprotein and triacylglycerols were measured by commercially available enzymatic assays. Bone density was investigated by dual energy X-ray densitometry performed on the lower spine and hips.
Results: Concentrations of LP-PLA(2) were significantly elevated in the patients with bone resorption compared to the control group of healthy individuals (225 ng/mL vs. 192 ng/mL, p<0.001) with the highest difference in patients with a T score below -2.5 SD (227 vs. 192 ng/mL). Serum levels of Lp-PLA(2) also negatively correlated with decreased levels of serum osteocalcin in patients, and a significant difference in Lp-PLA(2) (p=0.02) levels was observed between the control group and group with low levels of osteocalcin.
Elevated Lp-PLA(2) levels were significantly associated with the therapeutic procedures used, but not with age, gender and concentration of lipids. Conclusions: Lipoprotein-associated phospholipase A(2) seems to play an important role also in bone metabolism.