| ObjectiveTo study the sodium-phosphate cotransporter (Pit-1) and bone morphogeneticprotein-2(BMP-2) expressions in the radial arteries from uremia patients and theirrelationships with histological changes.MethodsA piece of radial artery was removed from45uremia patients during arterialvenous fistular operation.Ten patients with subtotal gastrectomy and normal renalfunction were chosen as controls. Segments of radial arteries were obtained from allof uremic subjects and evaluated by HE, Masson and von Kossa staining.Theexpressions of sodium-phosphate cotransporter (Pit-1) and bone morphogeneticprotein-2(BMP-2) were detected by immunohistochemistry and compared withcontrols. Other related factors including serum phosphate, calcium, C-reactiveprotein(CRP), intact parathyroid hormone(iPTH), triglyceride(TG), cholesterol(TC)and low-density lipoproteins(LDL) were also detected and compared with controls.Results1. Non-calcified aorta specimens presented uniformly normal media in whichmost of smooth muscle cells were neatly arranged, less matrix and collagen fibers.More than one half calcified aorta specimens presented thickened media anduniformly thickening intima, in which most of smooth muscle cells were disorder. Thethickened media, with reduced elastin, increased collagen fibers and matrix. Theuniformly thickening intima, in which most of matrix was abundant in collagen fibers,was not found calcium deposition.2. Twenty-four (53.33％) of uremia patients had no evidence of calcification,eleven (24.44％) vessels had mild/moderate calcification and ten (22.22％) hadsevere calcification, while calcification was not found in controls. Most calcificationoccurred in medial layer. 3. Staining for Pit-1was marked in the media from uremia patients and controls.The expression of Pit-1in the mild/moderate calcified aortic specimens and severecalcified aortic specimens was significantly more marked compared withnon-calcified aortic specimens and controls (P<0.01). Staining for BMP-2wassignificantly more intense in calcified versus non-calcified aortic specimens andcontrols (P<0.01). And there were12specimens of the non-calcified aortic thatpresented positive immunohistochemical staining of BMP-2, while not in controls.Staining for Pit-1and BMP-2was significantly more marked in non-calcified aorticspecimens compared with from controls (P<0.01). Staining for Pit-1and BMP-2wassignificantly more marked in severe calcified aortic specimens compared with frommild/moderate calcified aortic specimens (P<0.05).4. The occurrence of calcification was associated with the history of diabetes andcalcification score was positively correlated with serum phosphorus,calcium×phosphorus product and CRP (P<0.05). The staining for Pit-1and BMP-2inthe uremia patients significantly correlated with serum phosphorus,calcium×phosphorus product and CRP (P<0.01). And aslo the staining for Pit-1significantly correlated with the staining for BMP-2(P<0.01).Conclusions1. The incidence of radial artery calcification from uremic patients is muchhigher than the general community. Radial artery calcification of uremia patients wasmainly located in medial1ayer and was positively correlated with serum phosphorus,calcium×phosphorus product, CRP and the history of diabetes.2. In uremia patients, The increased expression of Pit-1not only mediated thetransportation of phosphate, but also closely correlated with calcification score andparticipated in the development of vascular calcification.3. Vascular calcification is related to the deposition of BMP-2in the radial arteryof uremia patients. Before vascular calcification, BMP-2in radial artery wassignificantly upregulated. It may be the early biological markers of vascularcalcification.4. In uremia patients, vascular smooth muscle cells which lost their original histological features resembled developmental osteogenesis. This implies an activecell-mediated process. |
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