title: Osteogenesis of heterotopically transplanted mesenchymal stromal cells in rat models of chronic kidney disease.
abstract: The current study is based on the hypothesis of mesenchymal stromal cells (MSCs) contributing to soft-tissue calcification and ectopic osteogenesis in chronic kidney disease (CKD). Rat MSCs were transplanted intraperitoneally in an established three-dimensional collagen-based model in healthy control animals and two rat models of CKD and vascular calcification: (1) 5/6 nephrectomy + high phosphorus diet; and (2) adenine nephropathy. As internal controls, collagen gels without MSCs were transplanted in the same animals. After 4 and 8 weeks, MSCs were still detectable and proliferating in the collagen gels (fluorescence-activated cell sorting [FACS] analysis and confocal microscopy after fluorescence labeling of the cells). Aortas and MSC-containing collagen gels in CKD animals showed distinct similarities in calcification (micro-computed tomography [µCT], energy-dispersive X-ray [EDX] analysis, calcium content), induction of osteogenic markers, (ie, bone morphogenic protein 2 [BMP-2], Runt related transcription factor 2 [Runx2], alkaline phosphatase [ALP]), upregulation of the osteocytic marker sclerostin and extracellular matrix remodeling with increased expression of osteopontin, collagen I/III/IV, fibronectin, and laminin. Calcification, osteogenesis, and matrix remodeling were never observed in healthy control animals and non-MSC-containing collagen gels in all groups. Paul Karl Horan 26 (PKH-26)-labeled, 3G5-positive MSCs expressed Runx2 and sclerostin in CKD animals whereas PKH-26-negative migrated cells did not express osteogenic markers. In conclusion, heterotopically implanted MSCs undergo osteogenic differentiation in rat models of CKD-induced vascular calcification, supporting our hypothesis of MSCs as possible players in heterotopic calcification processes of CKD patients.
authors.affiliation: Division of Nephrology and Clinical Immunology, Medical Faculty Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen University, Aachen, Germany; Institute of Pathology, Medical Faculty Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen University, Aachen, Germany.
authors.forename: Rafael
authors.initials: R
authors.lastname: Kramann
authors.forename: Uta
authors.initials: U
authors.lastname: Kunter
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Brandenburg
authors.forename: Isabelle
authors.initials: I
authors.lastname: Leisten
authors.forename: Josef
authors.initials: J
authors.lastname: Ehling
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Klinkhammer
authors.forename: Ruth
authors.initials: R
authors.lastname: Knüchel
authors.forename: Jürgen
authors.initials: J
authors.lastname: Floege
authors.forename: Rebekka K
authors.initials: RK
authors.lastname: Schneider
mesh_terms: D000225:Adenine; D000818:Animals; D001011:Aorta / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002113:Calcification, Physiologic; D002454:Cell Differentiation; D002465:Cell Movement; D003094:Collagen / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000378:metabolism; D005782:Gels; D005786:Gene Expression Regulation; D005819:Genetic Markers; D007677:Kidney Function Tests; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D009392:Nephrectomy; D009930:Organic Chemicals / Q000378:metabolism; D010012:Osteogenesis; D020286:Pericytes / Q000378:metabolism; D051381:Rats; D051436:Renal Insufficiency, Chronic / Q000503:physiopathology / Q000628:therapy*; D016042:Transplantation, Heterotopic; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D019485:Bone Morphogenetic Proteins; D050659:Core Binding Factor Alpha 1 Subunit; D005782:Gels; D005819:Genetic Markers; D009930:Organic Chemicals; C070080:PKH 26; C486031:Sost protein, rat; D003094:Collagen; D000225:Adenine
keywords: CHRONIC KIDNEY DISEASE; MATRIX REMODELING; MESENCHYMAL STROMAL CELLS; OSTEOGENESIS; VASCULAR CALCIFICATION