Inflammatory responses in the kidney lead to tubulointerstitial fibrosis, a common feature of chronic kidney diseases. Here we examined the role of prostaglandin E(2) (PGE(2)) in the development of tubulointerstitial fibrosis. In the kidneys of wild-type mice, unilateral ureteral obstruction leads to progressive tubulointerstitial fibrosis with macrophage infiltration and myofibroblast proliferation. This was accompanied by an upregulation of COX-2 and PGE(2) receptor subtype EP(4) mRNAs. In the kidneys of EP(4) gene knockout mice, however, obstruction-induced histological alterations were significantly augmented. In contrast, an EP(4)-specific agonist significantly attenuated these alterations in the kidneys of wild-type mice. The mRNAs for macrophage chemokines and profibrotic growth factors were upregulated in the kidneys of wild-type mice after ureteral obstruction. This was significantly augmented in the kidneys of EP(4)-knockout mice and suppressed by the EP(4) agonist but only in the kidneys of wild-type mice. Notably, COX-2 and MCP-1 proteins, as well as EP(4) mRNA, were localized in renal tubular epithelial cells after ureteral obstruction. In cultured renal fibroblasts, another EP(4)-specific agonist significantly inhibited PDGF-induced proliferation and profibrotic connective tissue growth factor production. Hence, an endogenous PGE(2)-EP(4) system in the tubular epithelium limits the development of tubulointerstitial fibrosis by suppressing inflammatory responses.

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Background: Capillary pericytes (cPCs), the mural cells of microvessels, play an important role in the formation and maintenance of microvessels; however, little is known about the mechanisms of how cPCs regulate angiogenesis. To identify factors that modulate cPC function, genes whose levels were altered in cPCs during neovessel formation were identified through a microarray screen. Methods and Results:Ninjurin1 (nerve injury-induced protein, Ninj1) was selected as a candidate factor for angiogenesis regulation. Ninj1 was expressed in capillary cells including endothelial cells (cECs) and was expressed at a higher level in cPCs. Hypoxia induced the gene expression of Ninj1 in addition of vascular endothelial growth factor (VEGF) in cPCs. When cPCs were co-incubated with a thoracic aorta in a three-dimensional Matrigel system, the length of the EC-tubes sprouting from the aorta was increased. Small interfering RNA-mediated downregulation of Ninj1 in cPCs enhanced these cPCs-mediated angiogenic effects, whereas overexpression of Ninj1 attenuated their effects. The production of angiogenic growth factors, such as VEGF and angiopoietin 1, by cPCs was enhanced by the downregulation of Ninj1, and reduced by the overexpression of Ninj1. also determined. EC Tube Formation Angiogenesis AssayThe EC tube formation assay was performed as previously described. 14 A 40-μl volume of growth factor-reduced Matirgel was added to each well of a 96-well plate at room temperature. The gel was solidified at 37°C for at least 30 min and then seeded with 1×10 4 cells/well in 100 μl medium (EBM2 with 2% FBS and 10 ng/ml VEGF). The assay was performed in a CO2 incubator, with plates incubated at 37°C for 24 h. Images were obtained by phase contrast microscopy and the length of the tube-like structure in each well was measured at 40× magnification. Hind Limb Ischmia Surgery and ImmunocytochemistryMale C57BL/6 mice 12 weeks of age were used for experiments. All animal protocols were approved by the Animal Care and Use Committee of Asahikawa Medical University. Unilateral hindlimb ischemia (HLI) models were established by ligation and excision of the femoral artery/vein as previously described. 16 At predetermined time points, mice were sacrificed by overdose with a pentobarbital-based euthanasia solution (200 mg/kg by intraperitoneal injection). Gastrocnemius muscle samples were collected and stored at −80°C for quantitative polymerase chain reaction (qPCR) analysis. The histological assessment of ischemic limb tissue was performed 14 days after hindlimb surgery. Functional vessels were stained by injecting 300 μl phosphate-buffered saline (PBS) containing rhodamine-labeled G. simplicifolia lectin I (100 μg/ml, Vector Laboratories) via the tail vein. After 5 min, mice were sacrificed and perfused through the heart with PBS followed by 4% paraformaldehyde in PBS, and the gastrocnemius muscle was dissected and embedded in Tissue-Tek OCT medium. Ninj1 expression in 10-μm cross-sections was detected by immunocytochemistry using an anti-Ninj1 ...

Objective Patients with chronic kidney disease (CKD) are at a high risk for cardiovascular diseases including stroke. However, the characteristics of the stroke subtypes in patients with CKD remain to be determined. Methods We investigated the associations between stroke subtypes and estimated glomerular filtration rate (eGFR), and traditional risk factors in 451 (males, 239; mean age, 71.1 y) acute stroke patients at our hospital between 2006 and 2010. Results The stroke subtype was cardiogenic cerebral embolism in 129 (29%), cerebral hemorrhage in 104 (23%), unclassified cerebral infarction in 65 (14%), lacunar infarction in 65 (14%), subarachnoid hemorrhage in 41 (9%), atherothrombosis in 30 (7%), and transient ischemic attacks in 17 (4%). Among the 451 patients, 134 (30%) had CKD with eGFR <60 mL/min/1.73 m 2 . Compared with a group without CKD, mean age (75.9 vs. 69.0 years, p<0.05), the prevalence of atrial fibrillation (AF) (44% vs. 21%, p<0.01) and a history of cardiovascular disease (37% vs. 19%, p<0.01) were significantly higher in that with CKD. A comparison of stroke subtypes revealed a significantly higher incidence of cardiogenic cerebral embolism (36% vs. 26%, p<0.05) in the group with, than without CKD. Conclusion We showed the prevalence of CKD in about 30% of acute stroke patients, and those patients were older, had a significantly higher prevalence of AF and a higher rate of cardiogenic cerebral embolism compared with patients without CKD. Thus, strict control of blood pressure and management of AF should be important to prevent stroke among patients with CKD.

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