The impact of the Pro12Ala genotype of the PPARG gene on the osteoporosis parameters in postmenopausal women

Abstract

Postmenopausal osteoporosis is a systemic skeletal disease characterized by a decrease in bone mass and disruption of the bone microarchitecture, resulting in increased fragility. DXA scan (dual-energy X-ray absorptiometry) is the "gold standard" for the diagnosis of osteoporosis, while different serum or urine biomarkers are used in the measurement of bone turnover. PPAR-g belongs to the family of non-steroid nuclear receptors. It is predominantly expressed in adipocytes but it could be found in osteoblasts. Both types share a common precursor cell. Recent studies have indicated the important role of PPAR-g in bone remodeling. Substitution of C to G in an exon of the gene coding for this protein (PPARG) re-sults in Pro to Ala amino acid change at position 12, leading to decreased transcriptional activity of PPARG. The aim of our research was to deter-mine the association between the genotype Pro12Ala polymorphism of the PPARG gene and the value of measured bone mineral density (BMD) as well as biochemical parameters of osteoporosis in postmenopausal women. 82 patients with postmenopausal osteoporosis were included in the study. The analysis of the Pro12Ala genotype of the PPARG gene was done by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). The Pro12Ala variant (CG genotype) was found in 14 respondents (17%), while the Pro12Pro (CC genotype) was present in 68 patients (83%). There was no statistically significant difference between BMD values concerning the genotype. However, carriers of the G allele (Pro12Ala variant) had significantly higher levels of serum Beta-CTx, a biochemical marker of bone degradation (p=0.019). There was no association found between the Pro12Ala genotype of the PPARG gene and BMD in women with postmenopausal osteoporosis, but the genotype could affect serum Beta-CTx levels indicating increased bone degradation.