engleski

Bone markers reveal decreased collagen type I synthesis and change in bone turnover during bisphosphonate treatment in osteogenesis imperfecta

Continuous action of bone cells, i.e. remodeling of the skeleton, is reflected by measuring the products of their acitvity in serum or urine. Availability of method for determination of bone markers has provided scarce but valuable data on bone turnover in osteogenesis imperfecta patients and the utility of bone markers in evaluation of bisphosphonate treatment. It has been demonstrated that procollagen type I propteptide was reduced in children with osteogenesis imperfecta in comparison to healthy children, but other bone marker were not considerably different. In severely affected adults with osteogenesis imperfecta bon resorption markers were increased, but also both normal and reduced concentrations were found. Treatment with bisphosphonates caused reduction of bone markers. Our results in a follow-up of 26 osteogenesis imperfecta children and adults were similar. Levels of procollagen were below or within the reference range for premenopausal women in the majority of patients which were younger than 15 years, although increased concentrations would be expected due to intensive skeletal growth. Decreased procollagen in OI patients probably reflects less collagen type I formation and retarded skeletal growth. Effect of bisphosphonate therapy was observed as decrease in procollagen after commencement and as continouous decrease during therapy. Bone resorption in some children younger than 10 years was below the upper limit of reference range for premenopausal women, but increased in older patients. Similar to procollagen results, much higher levels of resorption markers characteristic of intensive growth and turnover would be expected, also suggesting growth impairment. It can be expected that clinical utility of bone markers in osteogenesis imperfecta patients will be validated after more experience is gathered generated by bisphosphonate treatment and biochemical assessment. In comparison to other metabolic bone disease, a benefit of a choice of specific bone marker and degree of change in monitoring can be expected.

osteogenesis imperfecta ; bone markers ; bisphosphonates

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