Osteocytic sclerostin expression as an indicator of altered bone turnover

peer reviewedRenal osteodystrophy (ROD) is a complex and serious complication of chronic kidney disease (CKD), a major global health problem caused by loss of renal function. Currently, the gold standard to accurately diagnose ROD is based on quantitative histomorphometric analysis of trabecular bone. Although this analysis encompasses the evaluation of osteoblast and osteoclast number/activity, tfigurehe interest in osteocytes remains almost nihil. Nevertheless, this cell type is evidenced to perform a key role in bone turnover, particularly through its production of various bone proteins, such as sclerostin. In this study, we aim to investigate, in the context of ROD, to which extent an association exists between bone turnover and the abundance of osteocytes and osteocytic sclerostin expression in both the trabecular and cortical bone compartments. Additionally, the effect of parathyroid hormone (PTH) on bone sclerostin expression was examined in parathyroidectomized rats. Our results indicate that PTH exerts a direct inhibitory function on sclerostin, which in turn negatively affects bone turnover and mineralization. Moreover, this study emphasizes the functional differences between cortical and trabecular bone, as the number of (sclerostin-positive) osteocytes is dependent on the respective bone compartment. Finally, we evaluated the potential of sclerostin as a marker for CKD and found that the diagnostic performance of circulating sclerostin is limited and that changes in skeletal sclerostin expression occur more rapidly and more pronounced. The inclusion of osteocytic sclerostin expression and cortical bone analysis could be relevant when performing bone histomorphometric analysis for diagnostic purposes and to unravel pathological mechanisms of bone disease

European Consensus Statement on the diagnosis and management of osteoporosis in chronic kidney disease stages G4–G5D

Controlling the excessive fracture burden in patients with chronic kidney disease (CKD) Stages G4–G5D remains an impressive challenge. The reasons are 2-fold. First, the pathophysiology of bone fragility in patients with CKD G4–G5D is complex and multifaceted, comprising a mixture of age-related (primary male/postmenopausal), drug-induced and CKD-related bone abnormalities. Second, our current armamentarium of osteoporosis medications has not been developed for, or adequately studied in patients with CKD G4–G5D, partly related to difficulties in diagnosing osteoporosis in this specific setting and fear of complications. Doubts about the optimal diagnostic and therapeutic approach fuel inertia in daily clinical practice. The scope of the present consensus paper is to review and update the assessment and diagnosis of osteoporosis in patients with CKD G4-G5D and to discuss the therapeutic interventions available and the manner in which these can be used to develop management strategies for the prevention of fragility fracture. As such, it aims to stimulate a cohesive approach to the management of osteoporosis in patients with CKD G4–G5D to replace current variations in care and treatment nihilism

Management of fracture risk in CKD : traditional and novel approaches

The coexistence of osteoporosis and chronic kidney disease (CKD) is an evolving healthcare challenge in the face of increasingly aging populations. Globally, accelerating fracture incidence causes disability, impaired quality of life and increased mortality. Consequently, several novel diagnostic and therapeutic tools have been introduced for treatment and prevention of fragility fractures. Despite an especially high fracture risk in CKD, these patients are commonly excluded from interventional trials and clinical guidelines. While management of fracture risk in CKD has been discussed in recent opinion-based reviews and consensus papers in the nephrology literature, many patients with CKD stages 3–5D and osteoporosis are still underdiagnosed and untreated. The current review addresses this potential treatment nihilism by discussing established and novel approaches to diagnosis and prevention of fracture risk in patients with CKD stages 3–5D. Skeletal disorders are common in CKD. A wide variety of underlying pathophysiological processes have been identified, including premature aging, chronic wasting, and disturbances in vitamin D and mineral metabolism, which may impact bone fragility beyond established osteoporosis. We discuss current and emerging concepts of CKD–mineral and bone disorders (CKD-MBD) and integrate management of osteoporosis in CKD with current recommendations for management of CKD-MBD. While many diagnostic and therapeutic approaches to osteoporosis can be applied to patients with CKD, some limitations and caveats need to be considered. Consequently, clinical trials are needed that specifically study fracture prevention strategies in patients with CKD stages 3–5D