The relationship between interleukin-1 and its receptor antagonist gene polymorphism and bone mineral density in postmenopausal Korean women

Abstract

Objective: The objectives were to investigate the relationship between polymorphisms in interleukin-1 (IL-1) and IL-1 receptor antagonist (IL-1ra) gene, and bone mineral density (BMD) in postmenopausal Korean women and to evaluate whether these polymorphisms affect the production of cytokines from whole blood cells.Design: Prospective study.Materials and Methods: IL-1 C511T polymorphism was analyzed by restriction fragment length polymorphism using AvaI after polymerase chain reaction (PCR) and the 86-base pair repeat polymorphism in the IL-1ra gene was examined by PCR and electrophoresis in 202 postmenopausal Korean women. Serum osteocalcin, and CrossLaps (CTX) were measured by immunoassay, and IL-1β and IL-1ra produced by whole blood cells that were cultured for 3 days was measured using enzyme-linked immunosorbent assay. BMD at the lumbar spine and proximal femur were determined by dual energy X-ray absorptiometry.Results: There were no significant differences in BMD of the lumbar spine and proximal femur or serum levels of bone turnover markers across the IL-1 genotypes. Four alleles in IL-1ra gene were identified: A1 (4 repeats), A2 (2 repeats), A3 (5 repeats), and A4 (3 repeats). BMD at the lumbar spine, and proximal femur in women carrying A2 allele, was significantly lower, compared with noncarriage of that allele. Serum osteocalcin levels in the former group were higher than the latter group, but no difference in serum CTX levels between two groups was observed. There were no differences in the distribution of IL-1 genotypes and IL-1ra A2 allele among normal, osteopenic, and osteoporotic postmenopausal women. The production of IL-1β and IL-1ra from whole blood cells was not different according to the IL-1 or IL-1 ra genotypes and the status of BMD.Conclusion: BMD of lumbar spine and proximal femur is associated with a polymorphism in IL-1ra gene in Korean women. Polymorphism of IL-1 and IL-1ra gene does not affect the production of cytokines from whole blood cells. Objective: The objectives were to investigate the relationship between polymorphisms in interleukin-1 (IL-1) and IL-1 receptor antagonist (IL-1ra) gene, and bone mineral density (BMD) in postmenopausal Korean women and to evaluate whether these polymorphisms affect the production of cytokines from whole blood cells. Design: Prospective study. Materials and Methods: IL-1 C511T polymorphism was analyzed by restriction fragment length polymorphism using AvaI after polymerase chain reaction (PCR) and the 86-base pair repeat polymorphism in the IL-1ra gene was examined by PCR and electrophoresis in 202 postmenopausal Korean women. Serum osteocalcin, and CrossLaps (CTX) were measured by immunoassay, and IL-1β and IL-1ra produced by whole blood cells that were cultured for 3 days was measured using enzyme-linked immunosorbent assay. BMD at the lumbar spine and proximal femur were determined by dual energy X-ray absorptiometry. Results: There were no significant differences in BMD of the lumbar spine and proximal femur or serum levels of bone turnover markers across the IL-1 genotypes. Four alleles in IL-1ra gene were identified: A1 (4 repeats), A2 (2 repeats), A3 (5 repeats), and A4 (3 repeats). BMD at the lumbar spine, and proximal femur in women carrying A2 allele, was significantly lower, compared with noncarriage of that allele. Serum osteocalcin levels in the former group were higher than the latter group, but no difference in serum CTX levels between two groups was observed. There were no differences in the distribution of IL-1 genotypes and IL-1ra A2 allele among normal, osteopenic, and osteoporotic postmenopausal women. The production of IL-1β and IL-1ra from whole blood cells was not different according to the IL-1 or IL-1 ra genotypes and the status of BMD. Conclusion: BMD of lumbar spine and proximal femur is associated with a polymorphism in IL-1ra gene in Korean women. Polymorphism of IL-1 and IL-1ra gene does not affect the production of cytokines from whole blood cells.