Hematopoetic endosteal niche evaluation on mice submitted to protein malnutrition

• Grant number: 12/02985-1
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2012
• End date: June 30, 2014
• Field of knowledge: Health Sciences - Medicine - Pathological Anatomy and Clinical Pathology
• Principal Investigator: Primavera Borelli Garcia
• Grantee: Primavera Borelli Garcia
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Renato Paulo Chopard ; Ricardo Ambrósio Fock ; Sergio Allegrini Junior ; Victor Elias Arana-Chavez

Abstract

Nutrition deficiency is traditionally classified according to its origin as primary, when the cause is inadequate ingestion or gastrointestinal disorders, and secondary, when there is a secondary disorder that causes the malnutrition. Protein-energy malnutrition (PEM) is the most common and important form of malnutrition, manly, in developing countries. The term PEM is used to describe a broad array of clinical conditions that includes Kwashiorkor (characterized by the presence of oedema), Marasmus (characterized by severe muscle wasting) and intermediate state Kwashiorkor-marasmatic. PEM predisposes to infection, impairs a number of physiological processes, including hematopoiesis leading to anemia, leukopenia and alterations in bone marrow. Our group has already reported that malnourished mice had more fibronectin accretion mainly in endosteal/paratrabecular sites of the sternum and more laminin deposition in perisinusal sites than controls. Endosteal cell activation and hyperplasia were found, suggesting their participation in the hematopoietic process. The endosteum is the interface between bone and bone marrow and contains a heterogeneous group of osteoblastic cells at various stages of differentiation and osteoclasts that dynamically balance bone formation. The endosteal niche serves as a reservoir for hematopoietic-progenitor stem cell (HPSC) storage in a quiescent state. Considering that PEM promotes bone marrow structural alterations and depletion of HPSC and changes cellular development, our aim is to evaluate PEM effects on the endosteal niche. For this, bone mineral density will be performed by x-rays. Endosteal cells will be analyzed by immunofluorescence (osteopontin) and by immunohistochemistry (osteonectin, osteocalcin, collagen type I, alkaline phosphatase, RANK, RANKL and osteoprotegerin). Femoral bone marrow cells will be characterized by flow cytometry. Gene and protein expression of osteopontin, osteonectin, osteocalcin, collagen type I, alkaline phosphatase, osterix, Runx2, RANK, RANK-L and osteoprotegerin will be performed by real time PCR and western blot, ex vivo and after culture. (AU)