title: Teriparatide (human parathyroid hormone (1-34)) inhibits osteogenic vascular calcification in diabetic low density lipoprotein receptor-deficient mice.
abstract: Cardiovascular calcification is a common consequence of diabetes. High fat diets induce diabetes and arterial calcification in male low density lipoprotein receptor (LDLR) -/- mice; calcification occurs via Msx2 signaling that promotes the osteogenic differentiation of arterial myofibroblasts. We studied regulation of arterial osteogenesis by human parathyroid hormone (PTH) (1-34) (also called teriparatide) in LDLR -/- mice fed diabetogenic diets for 4 weeks. LDLR -/- mice were treated with vehicle or 0.4 mg/kg of PTH(1-34) subcutaneously five times/week. Gene expression was determined from single aortas and hind limb RNA by fluorescence reverse transcription-PCR. Valve calcification was determined by histological staining of cardiac sections using image analysis to quantify valve leaflet mineralization. PTH(1-34) increased bone mineral content (by dual energy x-ray absorptiometry) in LDLR -/- mice, with induction of osseous osteopontin (OPN) expression and serum OPN levels (>150 nM); PTH(1-34) did not significantly change serum glucose, lipids, body weight, or fat mass. PTH(1-34) suppressed aortic OPN and Msx2 expression >50% and decreased cardiac valve calcification 80% (8.3 +/- 1.5% versus 1.4 +/- 0.5%; p < 0.001). Of the known circulating regulators of vascular calcification (OPN, osteoprotegerin, and leptin), PTH(1-34) regulated only serum OPN. We therefore studied actions of PTH(1-34) and OPN in vitro on cells induced to mineralize with Msx2. OPN (5-50 nM) reversed Msx2-induced mineralization. PTH(1-34) inhibited mineralization by 40% and down-regulated Msx2 in aortic myofibroblasts. PTH(1-34) inhibits vascular calcification and aortic osteogenic differentiation via direct actions and potentially via circulating OPN. PTH(1-34) exerts beneficial actions at early stages of macrovascular disease responses to diabetes and dyslipidemia.
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000378:metabolism; D003920:Diabetes Mellitus / Q000473:pathology; D015536:Down-Regulation; D005347:Fibroblasts / Q000378:metabolism; D015870:Gene Expression; D018398:Homeodomain Proteins; D006949:Hyperlipidemias; D008297:Male; D051379:Mice; D008954:Models, Biological; D010012:Osteogenesis; D053495:Osteopontin; D012313:RNA / Q000378:metabolism; D011973:Receptors, LDL / Q000235:genetics* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000378:metabolism; D015398:Signal Transduction; D013052:Spectrometry, X-Ray Emission; D019379:Teriparatide / Q000737:chemistry* / Q000494:pharmacology*; D015854:Up-Regulation
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C084119:MSX2 protein; D011973:Receptors, LDL; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; C506896:Spp1 protein, mouse; D053495:Osteopontin; D019379:Teriparatide; D012313:RNA; D002118:Calcium