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Bone growth occurs in the growth-plate cartilage located at the ends of long bones. Changes in the architecture, abnormalities in matrix organization, reduction in protein staining and RNA expression of factors involved in cell signaling have been described in the growth-plate cartilage of nephrectomized animals. These changes can lead to a smaller growth plate associated with decrease in chondrocyte proliferation, delayed hypertrophy, and prolonged initiation of mineralization and vascular invasion. As a result, chronic renal failure can result in stunted body growth and skeletal deformities. Multiple etiologic factors can contribute to impaired bone growth in renal failure, including suboptimal nutrition, metabolic acidosis, and secondary hyperparathyroidism. Recent findings have also shown the tight connection between chondro/osteogenesis, hematopoiesis, and immunogenesis. [ABSTRACT FROM AUTHOR]

Growth failure is a common and significant clinical problem for children on dialysis and often remains a major impediment to their rehabilitation. Early referral to a paediatric nephrology centre and appropriate management before the initiation of dialysis may significantly prevent growth deterioration. Growth in children on dialysis can be affected by nutritional, metabolic, and hormonal changes. Early diagnosis of malnutrition and aggressive management should be a priority. Gastrostomy feeding should be used when adequate oral intake to maintain normal height and weight velocity cannot be achieved. Active vitamin D metabolites should be used carefully, to prevent low-turnover bone disease. All children should have an adequate regimen of dialysis and an appropriate management of malnutrition, renal osteodystrophy, metabolic acidosis, salt wasting and anaemia, before recombinant human growth hormone (rhGH) administration is considered. The current challenge of reversing growth impairment in children on dialysis can only be achieved by optimization of their care. [ABSTRACT FROM AUTHOR]

Histomorphometric analysis of iliac bone samples is a key tool for studying bone metabolism and, to a lesser extent, bone mass and structure. Two types of bone metabolic activity can be distinguished: modeling and remodeling. Both processes are performed by the same effector cells, osteoblasts and osteoclasts, but differ in the way these cells are arranged. The main effect of remodeling is to renew bone, whereas modeling can lead to rapid changes in bone shape, size and mass. Standard histomorphometric analysis focuses on trabecular bone and therefore mainly provides information on remodeling. Remodeling activity changes markedly with age during development. This must be taken into account when histomorphometry is used in the pediatric setting. Remodeling disorders encountered in the context of pediatric renal bone disease include mineralization defects, as well as abnormally high remodeling activity due to secondary hyperparathyroidism or suppressed remodeling activity as a consequence of over-treatment. Children and adolescents with severe bone fragility should have a bone biopsy unless the diagnosis is obvious from noninvasive examinations. Histomorphometric analysis of transiliac bone biopsy samples is especially valuable in clinical studies, as this method provides safety and efficacy data that cannot be obtained in any other way. [ABSTRACT FROM AUTHOR]