Calcification and osteopontin localization in the peritoneum of patients on long-term continuous ambulatory peritoneal dialysis therapy.

BACKGROUND: Peritoneal calcification is an uncommon complication of continuous ambulatory peritoneal dialysis (CAPD), which is mainly observed in patients on long-term therapy. Although some asymptomatic patients must have microscopic calcification in their peritoneum, little information on this topic has been published. Recent studies have revealed active participation of adhesive/chemotactic protein osteopontin (OPN) in dystrophic calcification. METHODS: Peritoneal tissue was obtained by biopsy or at autopsy from 18 CAPD patients (median duration, 122 months), 5 control haemodialysis (HD) patients, and 3 pre-CAPD patients. The distribution of calcium deposits and OPN protein was determined by von Kossa staining and immunohistochemistry, respectively. Smooth muscle cells and macrophages were identified with anti-alpha smooth muscle actin (alpha-SMA) and anti-CD68 antibodies. RESULTS: Calcium deposits with various configurations were observed in specimens from 12 of the 18 CAPD patients. They included massive calcification facing the peritoneal cavity, scattered granular or crystalloid deposits in the submesothelial stroma, and oval-shaped deposits formed within hyalinized vasa. Most were present in highly sclerosed areas and accompanied by extracellular OPN precipitation. Cytoplasmic OPN was detected in infiltrating leukocytes, granulation tissue cells, fibroblast-like cells and mast cells. Computerized tomography examination also detected peritoneal calcification in seven of the CAPD patients. No calcium deposits or OPN staining was detected in control specimens. CONCLUSIONS:The results of our study suggest that microscopic peritoneal calcification is frequent in patients on CAPD for more than 10 years. Myofibroblast infiltration, OPN expression, calcium deposition, and associated OPN precipitation seem to be components of the peritoneal changes in such patients.     

Altered osteoclast development and function in osteopontin deficient mice

The role of osteopontin in bone resorption was elucidated by studies of mice with knock out of the osteopontin gene generated by a different approach compared to previous models. Thus, a targeting vector with the promoter region as well as exons 1, 2, and 3 of the osteopontin gene was replaced by a loxP‐flanked Neo‐TK cassette, and this cassette was eliminated through transient expression of Cre recombinase. The recombined ES cells were used to create mice lacking expression of the osteopontin gene. Tissues from these mice were subjected structural and molecular analyses including morphometry and proteomics. The bone of the null mice contained no osteopontin but showed no significant alterations with regard to other bone proteins. The bone volume was normal in young null animals but in the lower metaphysis, the volume and number of osteoclasts were increased. Notably, the volume and length of the osteoclast ruffled border was several folds lower, indicating a lower resorptive capacity. The null mice did not develop the bone loss characteristic for osteoporosis demonstrated in old wild‐type female animals. This quantitative study demonstrates a bone phenotype in the osteopontin null mice of all ages. The data provides further evidence for a role of osteopontin in osteoclast activity. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:721–728, 2008     

血清骨桥蛋白和CA125联合检测鉴别良恶性腹水

目的：探讨联合检测血清骨桥蛋白（OPN）和CA125在良恶性腹水中的诊断价值。方法：取39例恶性腹水患者、48例结核性腹水患者及40例健康妇女血清样品,分别用双抗体夹心酶联免疫吸附法（ELISA）及微粒子化学发光法测定其OPN和CA125水平,观察其在诊断良、恶性腹水时的敏感性和特异性。结果：恶性腹水患者血清OPN水平明显高于结核性腹水患者及健康妇女组。OPN检测恶性腹水的敏感度、特异度分别为84.6%、95.0%;CA125检测敏感度、特异度为76.9%、87.5%;联合检测敏感度97.4%、特异度为95.0%。联合检测OPN、CA125较单独检测OPN及CA125其敏感度高（P〈0.05）;特异度无明显差异。结论：OPN与CA125联合测定是鉴别卵巢癌和结核性腹水的有效方法,联合检测CA125可提高其临床应用价值。     

Endometrial Osteopontin mRNA Expression and Plasma Osteopontin Levels are Increased in Patients with Endometriosis

Problem  The aim of this study was to evaluate osteopontin (OPN) mRNA expression in eutopic endometrium and plasma OPN levels in patients with endometriosis.
Method of study  A total of 79 patients with histologically confirmed endometriosis and 43 patients without endometriosis participated in this study. OPN mRNA expression in endometrial tissues was measured by real-time quantitative polymerase chain reaction (PCR) and plasma concentrations of OPN were quantified using a specific commercial sandwich enzyme-linked immunosorbent assays (ELISA).
Results  Osteopontin mRNA expression in endometrial tissue was significantly higher in women with endometriosis than in controls ( P =  0.010). The mean plasma levels of OPN (mean ± S.E.M.) in patients with endometriosis and controls were 407.31 ± 37.80 ng/mL and 165.84 ± 19.29 ng/mL, respectively ( P  < 0.001). Receiver operating characteristic (ROC) analysis for plasma OPN revealed an area under the curve (AUC) of 0.894, with a sensitivity of 93.0%, specificity of 72.4%, positive likelihood ratio of 3.37, and negative likelihood ratio of 0.1 using a cut-off value of 167.68 ng/mL.
Conclusion  Osteopontin may be involved in the pathogenesis of endometriosis and plasma OPN may be a useful non-invasive marker for the diagnosis of endometriosis.     

Osteopontin expression in pulmonary tumor thrombotic microangiopathy caused by gastric carcinoma

Pulmonary tumor thrombotic microangiopathy (PTTM) is characterized by fibrocellular intimal proliferation and thrombus formation in small pulmonary arteries and arterioles in patients with metastatic carcinoma. Osteopontin (OPN) is a multifunctional cytokine and adhesive protein, and has been demonstrated to be implicated in fibrosis, neointima formation, arterial occlusion by thrombus, and tumor metastases in cooperation with platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Herein is described an autopsy case of gastric adenocarcinoma with severe pulmonary hypertension due to PTTM. Histologically, tumor cell emboli markedly induced both fibromuscular intimal thickening and thrombosis, resulting in luminal stenosis and occlusion of small pulmonary arteries and arterioles. Tumor cells, both in the PTTM lesions and primary gastric carcinoma, had positive immunoreactivity for OPN, PDGF, and VEGF. In addition, proliferating fibromuscular intimal cells also showed expression of OPN, PDGF, and VEGF. These findings suggest that OPN may be involved in fibrocellular intimal proliferation and thrombus formation in PTTM together with PDGF and VEGF. To the best of the authors' knowledge this is the first report to demonstrate the possible involvement of OPN in PTTM. It is postulated that OPN is one of the candidate molecules for the development of PTTM.     

COMPUTER‐AIDED ULTRASONOGRAPHY (HISTOSCANNING): A NOVEL TECHNOLOGY FOR LOCATING AND CHARACTERIZING PROSTATE CANCER

OBJECTIVE

To test the hypothesis that exposure of a renal epithelial cell line, NRK52E, to calcium oxalate monohydrate crystals (COM) would up‐regulate NADPH oxidase subunit p47^phox, enhance superoxide production and increase monocyte chemoattractant protein‐1 (MCP‐1) and osteopontin mRNA levels.

MATERIALS AND METHODS

Confluent cultures of NRK52E cells were exposed to COM (66.7 µg/cm²) with or with no pretreatment with diphenileneiodium chloride (DPI, 10 × 10^?6m ) an inhibitor for NADPH oxidase, under serum‐free conditions. The conditioned medium was collected and total cellular RNA isolated from the cells, and subjected to enzyme‐linked immunosorbent assay and real‐time polymerase chain reaction (PCR). Production of reactive oxygen species (ROS) was estimated by dihydroethidium (DHE) staining using a fluorescence microscope. Immunohistochemistry and real‐time PCR were used to analyse p47^phox in NRK52E cells.

RESULTS

In COM treated NRK52E cells there was enhanced expression of p47^phox and production of superoxide. COM‐induced production of MCP‐1 and osteopontin was significantly reduced after treatment with DPI.

CONCLUSIONS

While the generation of a lot of ROS might play a major role in tissue injury or death, the regulated generation of low concentration of ROS, possibly by NADPH oxidase, may represent a second messenger system for generation of COM‐induced MCP‐1 and osteopontin production in the renal tubules.     

骨关节炎中骨桥蛋白表达及意义

目的:探讨细胞因子-骨桥蛋白(OPN)在骨关节炎(osteoarthritis,OA)患者中的表达情况及意义。方法:选取接受膝关节置换手术治疗的骨性关节炎患者软骨标本42例,按Mankin评分分为轻度退变、中度退变、重度退变3组,取正常膝关节软骨10例作为对照组;对标本进行免疫组织化学染色,测定OPN表达情况。结果:OA组OPN吸光度明显高于正常组,差异有统计学意义(P<0.05);OPN在轻、中、重度退变组的表达差异有统计学意义(P<0.05);OPN平均灰度值与Mankin病理评分呈显著负相关(r=-0.872,P<0.01)。结论:OPN在骨关节炎软骨中高表达,且与病变程度相关,与骨关节炎发生发展也有密切关系。     

骨桥蛋白与VEGF在增生性糖尿病视网膜病变玻璃体液中的表达

目的:探讨骨桥蛋白(osteopontin,OPN)与血管内皮生长因子(vascular endothelial growth factor,VEGF)在增生性糖尿病视网膜病变(proliferative diabetic retinopathy PDR)中的作用,并初步分析OPN及VEGF与PDR间的相关关系,为研究PDR的发病机制、预防及治疗提供实验依据和理论基础。方法:取2008年3月至2008年12月间PDR 28例(PDR组)和特发性黄斑裂孔(IMH)24例(IMH组)患者的玻璃体液样本,采用酶联免疫吸附试验(ELISA)定量测定玻璃体液中OPN及VEGF浓度,应用SPSS 11.5统计学软件进行数据分析。结果:PDR组玻璃体液中OPN浓度为(883.39±151.12)ng.ml-1,VEGF浓度为(1 158.68±140.98)pg.ml-1;IMH组OPN浓度为(537.88±166.37)ng.ml-1,VEGF浓度为(295.91±109.62)pg.ml-1。PDR组较IMH组不仅OPN表达增高(P<0.01),VEGF也表达增高(P<0.01);PDR组玻璃体液中OPN浓度与VEGF...