Department of Nephrology and Clinical Immunology, Medical Faculty RWTH, Aachen University, Aachen, Germany.
Arterioscler Thromb Vasc Biol. 2011 Sep;31(9):e45-54. doi: 10.1161/ATVBAHA.111.228601. Epub 2011 Jun 16.
Medial artery calcification in patients with chronic kidney disease proceeds through intramembranous ossification resulting from osteoblast-induced calcification of the collagen extracellular matrix. The current study is based on the hypothesis that mesenchymal stem cells (MSC) constitute critical cells for procalcific extracellular matrix remodeling in patients with chronic kidney disease.
Human MSC were cultured in media supplemented with pooled sera from either healthy or uremic patients (20%). Exposure to uremic serum enhanced the proliferation of MSC (cell counting, BrdU incorporation) whereas apoptosis and necrosis were not affected (annexin V and 7-amino-actinomycin staining). Uremic serum-exposed MSC recapitulated osteogenesis by matrix calcification and expression of bone-related genes (bone morphogenetic protein [BMP]-2 receptor, alkaline phosphatase, osteopontin, and Runx2) in 35 days. The uremic serum-induced osteogenesis was completely blocked by a BMP-2/4 neutralizing antibody or the natural antagonist NOGGIN. Calcification and matrix remodeling were further analyzed in a collagen-embedded osteogenesis model recapitulating the vascular collagen I/III environment. The uremic serum-induced calcification was shown to occur along collagen fibers as shown by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and von Kossa staining and was accompanied by extensive matrix remodeling.
Uremic serum induced in a BMP-2/4-dependent manner an osteoblast-like phenotype in MSC accompanied by matrix remodeling and calcification.
慢性肾脏病患者的股动脉钙化是通过成骨细胞诱导细胞外基质胶原发生钙化而导致的膜内成骨。本研究基于这样一种假说，即间充质干细胞（MSC）是慢性肾脏病患者促钙化细胞外基质重塑的关键细胞。
将人 MSC 在补充有健康或尿毒症患者血清（20%）的培养基中培养。暴露于尿毒症血清增强了 MSC 的增殖（细胞计数、BrdU 掺入），而凋亡和坏死不受影响（Annexin V 和 7-氨基放线菌素 D 染色）。尿毒症血清暴露的 MSC 通过基质钙化和骨相关基因（骨形态发生蛋白[BMP]-2 受体、碱性磷酸酶、骨桥蛋白和 Runx2）的表达在 35 天内重新形成成骨作用。BMP-2/4 中和抗体或天然拮抗剂 Noggin 完全阻断尿毒症血清诱导的成骨作用。在胶原包埋成骨模型中进一步分析钙化和基质重塑，该模型模拟血管胶原 I/III 环境。扫描电子显微镜、能谱 X 射线和 von Kossa 染色显示，尿毒症血清诱导的钙化沿着胶原纤维发生，并伴有广泛的基质重塑。
尿毒症血清以 BMP-2/4 依赖的方式诱导 MSC 呈现成骨样表型，同时伴有基质重塑和钙化。
