ABSTRACT
Objective To investigate the relationship between geranylgeranyl pyrophosphate synthase (GGPPS) gene polymorphisms and bone response to alendronate in Chinese osteoporotic women.Methods A total of 639 postmenopausal women with osteoporosis or osteopenia were included and randomly received treatment of low dose (70 mg per two weeks) or standard dose (70 mg weekly) of alendronate for one year. The six tag single nucleotide polymorphisms of GGPPS gene were identified. Bone mineral density (BMD), serum cross-linked C-telopeptide of type I collagen (β-CTX), and total alkaline phosphatase (ALP) were measured before and after treatment. GGPPS gene polymorphisms and the changes of BMD and bone turnover markers after treatment were analyzed.Results rs10925503 polymorphism of GGPPS gene was correlated to serum β-CTX levels at baseline, and patients with TT genotype had significantly higher serum β-CTX level than those with TC or CC genotype (all P<0.05). No correlation was found between polymorphisms of GGPPS gene and serum total ALP levels, as well as BMD at baseline. After 12 months of treatment, lumbar spine and hip BMD increased and serum bone turnover markers decreased significantly (P<0.01), and without obvious differences between the low dose and standard dose groups (all P>0.05). However, GGPPS gene polymorphisms were uncorrelated to percentage changes of BMD, serum total ALP, and β-CTX levels (all P>0.05).Conclusion GGPPS gene polymorphisms are correlated to osteoclasts activity, but all tag single nucleotide polymorphisms of GGPPS gene have no influence on the skeletal response to alendronate treatment.
ABSTRACT
<p><b>BACKGROUND</b>Osteogenesis imperfecta (OI) is a rare bone disease and its effective treatment is relatively deficient. We tried to assess the effects of new bisphosphonate, ibandronate on children with OI.</p><p><b>METHODS</b>In this open-label, prospective, controlled study, 30 children with OI were enrolled. They received either infusions of ibandronate (2 mg) in every three months or oral calcitriol 0.25 µg daily for 24 months. All patients took 500 mg calcium plus 200 U vitamin D daily together. The endpoints were the change of annual new fracture rate (observed by case history and X ray films of spine), bone mineral density (BMD, measured by dual energy X-ray absortiometry), serum concentration of carboxy-telopeptide cross-links of type I collagen (CTX, bone resorption marker) and alkaline phosphatase (ALP, bone formation marker) during the follow-up.</p><p><b>RESULTS</b>After the cyclic infusions of ibandronate, the annual new fracture rate was significantly decreased from 1.9 to 0.13 time, obviously lower than that of calcitriol group, which decreased from 1.8 to 1.0 time after the treatment (P < 0.001). The significant increase of BMD at the lumbar spine, femoral neck, trochanter, total hip was found in the group of ibandronate by 59.0%, 42.0%, 47.5% and 36.6% in time dependent manner (compared with the baseline, P < 0.001). The increase of BMD in ibandronate group was greater than that of calcitriol group (P < 0.001). The concentrations of ALP and CTX were obviously decreased in ibandronate group, and the reduction of CTX was more significant than that of ALP (P < 0.001). The tolerance of the children to ibandronate was quite well. Mild fever and muscle pain were found in 9 cases within 1 - 3 days after the first infusion of ibandronate, which could relieve after 1 - 2 days without special management.</p><p><b>CONCLUSIONS</b>The benefits of cyclic infusions of ibandronate to children with OI are significant because ibandronate could significantly reduce annual bone fracture rate, increase lumbar and hip BMD, preserve vertebral morphometry of patients through inhibition of bone resorption.</p>