Endocrine Abstracts

A number of new treatments are being developed for the treatment of bone diseases, particularly osteoporosis. We need tools to help identify how these drugs work and which bone compartment they affect. Bone turnover markers are very useful in identifying response to treatment in these allow identification of an early change and information about mechanism. New biochemical tests have become available that allow study of the key regulatory pathways in bone – these include osteoprotegerin, RANKL and DKK1. The mechanism can also be studied by bone histomorphometry. There have been two important developments here – the use of quadruple labelling allows the study of an anabolic effect on a single bone biopsy that has been labelled with tetracycline before and after starting the treatment. The use of microCT has been applied to these same bone biopsies and this technique allows study of changes in bone structure. The use of quantitative computed tomography allows non-invasive study of the trabecular and cortical bone compartments. The introduction of high resolution CT (resolution less than 100 microns) allows study of the forearm and tibia) and moderate resolution CT (resolution less than 1 mm) allows more detailed study of the spine and proximal femur.