Osteocyte proteins and role in the physiopathology of aluminium-related and unrelated osteomalacia.

• Grant number: 22/07687-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2022
• End date: February 29, 2024
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Vanda Jorgetti
• Grantee: Daniel Souza Gonçalves de Araujo
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Background: The osteocytes represent about 95% of all cells in the bone tissue compared with 4-6% of osteoblasts and 1-2% of osteoclasts. The osteocytes express a wide range of proteins that can be subdivided in three groups: 1) proteins that regulates bone remodeling; 2) proteins related to the metabolism of phosphorus (P) and bone mineralization; 3) proteins that act in generation of the dendritic processes of these cells and in their cytoskeletal function and promotes the differentiation of osteoblasts into osteocytes.Chronic kidney disease (CKD) is one of the several conditions that lead to damage of this well-organized tissue. Among all the bone complications presented in patients with CKD, the osteomalacia (OM) is the least studied. OM is a defect in the mineralization of the newly formed osteoid tissue. The diagnosis is made through bone biopsy and histomorphometric analysis after double-labeling with tetracycline. This procedure is frequently performed in our center and we still observe the presence of aluminium (Al) around 38% of patients submitted to biopsy. Considering our findings, we believe this problem is local and underdiagnosed in other centers. No studies so far have investigated the role of osteocytes and proteins in Al related OM and other types of OM. Objective: characterize and quantify the expression of osteocyte proteins in bone tissue by immunohistochemistry and relate to the bone histomorphometric analysis in patients with OM related or unrelated to Al. Methods: Retrospective, observational, longitudinal, non-randomised controlled study realized by search in biopsy database. Expected results: We aim this study will contribute to explain the physiopathology of Al-related and unrelated OM in patients with chronic kidney disease.