Correction: Role of the high-affinity leukotriene B4 receptor signaling in fibrosis after unilateral ureteral obstruction in mice.

[This corrects the article DOI: 10.1371/journal.pone.0202842.].

Role of the high-affinity leukotriene B4 receptor signaling in fibrosis after unilateral ureteral obstruction in mice.

Leukotriene B4 (LTB4) is a lipid mediator that acts as a potent chemoattractant for inflammatory leukocytes. Kidney fibrosis is caused by migrating inflammatory cells and kidney-resident cells. Here, we examined the role of the high-affinity LTB4 receptor BLT1 during development of kidney fibrosis induced by unilateral ureteral obstruction (UUO) in wild-type (WT) mice and BLT1 knockout (BLT1-/-) mice. We found elevated expression of 5-lipoxygenase (5-LOX), which generates LTB4, in the renal tubules of UUO kidneys from WT mice and BLT1-/- mice. Accumulation of immunoreactive type I collagen in WT UUO kidneys increased over time; however, the increase was less prominent in BLT1-/- UUO kidneys. Accumulation of S100A4-positive fibroblasts increased temporally in WT UUO kidneys, but was again less pronounced in-BLT1-/- UUO kidneys. The same was true of mRNA encoding transforming growth factor-ß (TGF)-ß and fibroblast growth factor (FGF)-2. Finally, accumulation of F4/80-positive macrophages, which secrete TGF-ß, increased temporally in WT UUO and BLT1-/- UUO kidneys, but to a lesser extent in the latter. Following LTB4 stimulation in vitro, macrophages showed increased expression of mRNA encoding TGF-ß/FGF-2 and Col1a1, whereas L929 fibroblasts showed increased expression of mRNA encoding α smooth muscle actin (SMA). Bone marrow (BM) transplantation studies revealed that the area positive for type I collagen was significantly smaller in BLT1-/-BM→WT than in WT-BM→WT. Thus, LTB4-BLT1 signaling plays a critical role in fibrosis in UUO kidneys by increasing accumulation of macrophages and fibroblasts. Therefore, blocking BLT1 may prevent renal fibrosis.

New Anti-Nephrin Antibody Mediated Podocyte Injury Model Using a C57BL/6 Mouse Strain.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) is considered a subset of the podocytopathies. The molecular pathogenesis of podocytopathy is still unknown. There has not been an experimental animal model of isolated podocytopathy induced by antibody in C57BL/6 strain, which is widely used as the genetic background. Nephrin is closely associated with the slit diaphragm of the glomerular podocyte, and has recently received attention as a potential therapeutic target. The function of nephrin, especially its role in FSGS development via podocytopathy, is being elucidated. We report our experience with a C57BL/6 FSGS model induced by polyclonal rabbit anti-mouse nephrin antibody (α-mNep Ab). METHODS: α-mNep Ab, which was generated by genetic immunization, was administered into C57BL/6 mice at once, intravenously. Urinary protein excretion, the development of glomerulosclerosis and the number of podocyte in mouse kidney were evaluated. RESULTS: The α-mNep Ab-induced FSGS was associated with massive proteinuria and nephrotic syndrome. In periodic acid-Schiff staining, FSGS was observed from day 7 after antibody injection. Podocyte numbers and podocyte marker (anti-Wilms tumor 1 and anti-synaptopodin)-positive areas were clearly decreased. These results suggest that this FSGS mouse model reliably reproduces the human nephrotic syndrome and FSGS. CONCLUSION: We succeeded in making the nephrotic syndrome model mice induced by α-mNep Ab using C57BL/6. This model may be useful for studying the mechanisms of podocytopathy.

Comparison of nephrotoxicity between two gadolinium-contrasts, gadodiamide and gadopentetate in patients with mildly diminished renal failure.

Although gadolinium (Gd)-based contrast media have been found to be nephrotoxic, their nephrotoxicity, and the dependence of nephrotoxicity on chelate types, have not been assessed in patients with normal or mildly diminished renal failure. This prospective, randomized study compared the nephrotoxicity of low doses of the nonionic Gd-based contrast medium gadodiamide (Omniscan®) and the ionic Gd-based contrast medium gadopentetate (Magnevist®) in patients with serum creatinine < 1.6 mg/dL. Patients aged 20 to 80 years, weighing 45 to 70 kg and with normal or < 1.6 mg/dL Serum-creatinine in the 3 months prior to undergoing magnetic resonance imaging (MRI) of brain, were enrolled. Patients were randomized to receive 0.1 mol/kg gadodiamide or gadopentetate. Serum-creatinine, serum cystatin-C, estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) formula, and estimated creatinine clearance rate (eCCr) using the Cockcroft-Gault formula were measured just before and 16-80 hr after MRI. Groups were compared statistically by Mann-Whitney U-tests and Wilcoxon signed-rank tests. There were no significant differences in clinical characteristics between the gadodiamide (n = 43) and gadopentetate (n = 59) groups. Serum-creatinine, eGFR and eCCr before and 16-80 hr after MRI did not differ significantly within either group or between the two groups. Serum cystatin-C was significantly higher 16-80 hr after than before MRI only in the gadodiamide group (0.79 ± 0.21 vs. 0.74 ± 0.14 mg/L, p = 0.028). The ionic contrast medium, gadopentetate, did not affect renal function during MRI, whereas the nonionic contrast medium, gadodiamide, affected renal function transiently.

Garenoxacin pharmacokinetics in patients undergoing maintenance hemodialysis.

INTRODUCTION: Studies on the pharmacokinetics of the antibiotic garenoxacin (GRNX) in patients with renal insufficiency are lacking. In this study, we attempted to ascertain the appropriate dose of GRNX in patients undergoing maintenance hemodialysis (MH) based on pharmacokinetic parameters and clinical outcomes. METHODS: Six male patients with infections who were undergoing MH received 200 mg GRNX once daily. Blood samples were taken before and at 1, 2, 4, 6, 12, and 24 hours after GRNX administration. Plasma GRNX concentrations were measured using high-performance liquid chromatography. FINDINGS: The mean maximum plasma concentration (Cmax ) was 3.00 ± 1.12 µg/mL, time to maximum plasma concentration (Tmax ) was 3.0 ± 2.0 hours, and area under the curve for 24 hours (AUC0-24 ) was 40.7 ± 16.7 µg·h/mL. The half-life (T1/2 ) of GRNX could not be calculated because plasma concentrations remained high 24 hours after administration. Cmax was strongly associated with the GRNX dose per kilogram body weight (r = 0.85, P = 0.03). Clinically, fever resolved within 3 days of GRNX administration and C-reactive protein levels returned to normal 14 days after administration. One patient experienced temporary increases in serum transaminase levels. DISCUSSION: MH patients receiving 200 mg GRNX once daily for infection showed a reduced Cmax but similar AUC0-24 compared with healthy individuals. While this study evaluated the effect of GRNX treatment, further research is needed to assess the accumulation of GRNX and the impact of continuous administration on its pharmacokinetics, as well as to prevent the development of resistant mutants.

[Heparin-induced thrombocytopenia with pseudo-pulmonary embolism in a patient who was newly introduced to hemodialysis treatment].

Pseudo-pulmonary embolism (PPE) superimposed on heparin-induced thrombocytopenia (HIT) is an important complication in patients undergoing hemodialysis (HD) treatment. We report the clinical profile of an HD patient with acute respiratory distress induced by PPE and HIT. A 67-year-old man with diabetic nephropathy and end-stage renal failure developed congestive heart failure. He was admitted to Kitasato University Hospital. He was introduced to HD treatment using low-molecular-weight heparin as an anticoagulant for an HD session on day 1 of admission. On day 11 after admission, he suddenly developed respiratory distress and hypoxia at 30 min after the start of the fifth HD session. The HD session was immediately discontinued, and oxygen inhalation improved his complaints and hypoxia. The platelet count decreased from 220 x 10(9)/L at the start of the HD session to 80 x 10(9)/L at the end of the HD session. We suspected HIT when blood clotting occurred in his hemodialyzer and blood circuit for HD during the HD session on day 12. Chest X-ray, electrocardiogram, echocardiography, and pulmonary microcirculation scintigraphy were normal. Serum analysis was positive for heparin-platelet factor 4 (PF4) antibody. We then diagnosed him with PPE superimposed on HIT. After the anticoagulant agent for HD was changed from low-molecular-weight heparin to nafamostat mesilate, his clinical symptoms and thrombocytopenia disappeared. PPE superimposed on HIT appeared approximately 7-10 days after the initial use of heparin for the HD session. PPE also led to acute respiratory distress, blood coagulation in the hemodialyzer and blood circuit for HD, as well as thrombocytopenia with less than a 50% decrease in platelet counts. The prognosis of PEE and HIT is good after discontinuing the use of heparin.

A possible clue for the production of anti-glomerular basement membrane antibody associated with ureteral obstruction and hydronephrosis.

BACKGROUND: Anti-glomerular basement membrane (anti-GBM) antibody-mediated glomerulonephritis (anti-GBM GN) is an autoimmune disease with rapidly progressive glomerulonephritis. Based on a case report of anti-GBM GN following hydronephrosis, we hypothesized that hydronephrosis may act as a trigger for the development of anti-GBM antibodies. PATIENTS AND METHODS: We evaluated 11 patients who were diagnosed with hydronephrosis. It was measured with serum anti-GBM antibody. These patients' medical histories as well as risk factors for the development of anti-GBM antibodies and causes of hydronephrosis were reviewed. Renal function and hematuria were also considered. The serum anti-GBM antibody was measured with enzyme-linked immunosorbent assays (ELISA) or chemiluminescent enzyme immunoassays (CLEIA). Histopathological findings of renal biopsy specimens were also evaluated. RESULTS: No patient had a medical history of renal disease. Five patients had a history of smoking. Ten of the 11 patients had renal dysfunction as evidenced by serum creatinine levels of 0.85-13.8 mg/dl, while 8 patients had RBCs in their urinary sediment at the time of diagnosis for hydronephrosis. Two of the patients assessed by ELISA and CLEIA were positive for anti-GBM antibodies. In 1 of these 3 patients, anti-GBM antibodies and renal dysfunction improved upon treatment for hydronephrosis. Another of the 3 patients developed anti-GBM GN, but anti-GBM antibodies and renal dysfunction improved dramatically upon treatment. In the 3rd patient without improved hydronephrosis, anti-GBM antibodies and renal dysfunction remained unchanged. CONCLUSION: Our results provide insights into the development of anti-GBM antibodies in patients with ureteral obstruction and hydronephrosis.

Role of cyclooxygenase-2 in the development of interstitial fibrosis in kidneys following unilateral ureteral obstruction in mice.

Unilateral ureteral obstruction (UUO) induced tubulointerstitial fibrosis in kidneys mimics the pathogenesis of chronic kidney diseases and is considered a suitable model for studying the mechanisms leading to fibrosis. To study the role of cyclooxygenase-2 (COX-2) in kidney fibrosis, we investigated whether a selective COX-2 inhibitor, celecoxib, affected renal interstitial fibrosis during UUO in mice. To induce UUO, the left proximal ureter was ligated in male C57BL/6 mice. The mice were fed a diet with or without celecoxib from the day of UUO induction. Following UUO, the renal pelvis was observed to be dilated and the kidney cortex was significantly thinner than that of sham-operated mice. Immunofluorescent staining of type I, III, and IV collagen in UUO kidneys revealed that interstitial collagen deposition was significantly increased in the celecoxib-treated group. Expression of type I, III, and IV collagen in UUO kidneys was also significantly higher in the celecoxib-treated group than in the vehicle-treated group. In the celecoxib-treated group, mRNA levels of TGF-ß/FGF-2 were also significantly higher than those in the vehicle-treated group. The present study demonstrates that COX-2 plays a protective role against fibrosis in UUO kidneys and suggests that supplementation of COX-2 products, such as PG analogues, will be a good option for preventing interstitial fibrosis.

Lipoprotein subfractions highly associated with renal damage in familial lecithin:cholesterol acyltransferase deficiency.

OBJECTIVE: In familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD), deposition of abnormal lipoproteins in the renal stroma ultimately leads to renal failure. However, fish-eye disease (FED) does not lead to renal damage although the causative mutations for both FLD and FED lie within the same LCAT gene. This study was performed to identify the lipoproteins important for the development of renal failure in genetically diagnosed FLD in comparison with FED, using high-performance liquid chromatography with a gel filtration column. APPROACH AND RESULTS: Lipoprotein profiles of 9 patients with LCAT deficiency were examined. Four lipoprotein fractions specific to both FLD and FED were identified: (1) large lipoproteins (>80 nm), (2) lipoproteins corresponding to large low-density lipoprotein (LDL), (3) lipoproteins corresponding to small LDL to large high-density lipoprotein, and (4) to small high-density lipoprotein. Contents of cholesteryl ester and triglyceride of the large LDL in FLD (below detection limit and 45.8±3.8%) and FED (20.7±6.4% and 28.0±6.5%) were significantly different, respectively. On in vitro incubation with recombinant LCAT, content of cholesteryl ester in the large LDL in FLD, but not in FED, was significantly increased (to 4.2±1.4%), whereas dysfunctional high-density lipoprotein was diminished in both FLD and FED. CONCLUSIONS: Our novel analytic approach using high-performance liquid chromatography with a gel filtration column identified large LDL and high-density lipoprotein with a composition specific to FLD, but not to FED. The abnormal lipoproteins were sensitive to treatment with recombinant LCAT and thus may play a causal role in the renal pathology of FLD.

A multicenter cross-sectional study of circulating soluble urokinase receptor in Japanese patients with glomerular disease.

Elevated serum-soluble urokinase receptor (suPAR) levels have been described in patients with focal segmental glomerulosclerosis (FSGS) in several different cohorts. However, it remains unclear whether this is the case for Japanese patients and whether circulating suPAR can be clinically useful as a diagnostic marker. To determine this, we measured serum suPAR levels in 69 Japanese patients with biopsy-proven glomerular diseases in a cross-sectional manner. The serum suPAR levels showed a significant inverse correlation with renal function by univariate (R(2) of 0.242) and multivariate (ß=0.226) analyses. Even after excluding patients with renal dysfunction, no significant difference in the suPAR levels was detected among the groups. Receiver operating characteristic analysis and measures of the diagnostic test performance showed that suPAR was not a useful parameter for differentiating FSGS from the other glomerular diseases (AUC-ROC: 0.621), although a small subgroup analysis showed that patients with FSGS, treated with steroids and/or immunosuppressants, had significantly lower suPAR levels. Patients with ANCA-associated glomerulonephritis had significantly higher levels of suPAR compared with the other disease groups, which may be owing to their lower renal function and systemic inflammation. Thus, suPAR levels are significantly affected by renal function and have little diagnostic value even in patients with normal renal function.

Angiotensin receptor blocker (ARB)-diuretic versus ARB-calcium channel blocker combination therapy for hypertension uncontrolled by ARB monotherapy.

Diuretics or calcium channel blockers (CCBs) are used concomitantly with an angiotensin II receptor blocker (ARB). However, it is not established which ARB-based combination therapy is the most effective and safe. This prospective randomized open-label study compared the efficacy and safety of a fixed-dose tablet of losartan (LST)-hydrochlorothiazide (HCTZ) (n = 99) and LST-amlodipine (AML) (n = 77) in Japanese patients whose hypertension was uncontrolled by ARB monotherapy. Blood pressure changed similarly over the 12-month study period. Only LST-HCTZ significantly increased serum uric acid (SUA) in patients with low baseline SUA (<5.6 mg/dL) but not in patients with high baseline SUA.

[Definition, diagnosis, grading and treatment of chronic kidney disease (CKD): an update].

The concept and the definition of CKD proposed by The National Kidney Foundation (USA) have been there for 10 years. The Japanese Society of Nephrology also has conducted the education and the spread of CKD. Consequently, in 2009 the newly introduced dialysis patients reached the ceiling in number in Japan. Definition, diagnosis, grading and the treatment of CKD published in 2012 by The Japanese Society of Nephrology were reviewed in this article.

Amelioration of circulating lipoprotein profile and proteinuria in a patient with LCAT deficiency due to a novel mutation (Cys74Tyr) in the lid region of LCAT under a fat-restricted diet and ARB treatment.

Familial lecithin-cholesterol acyltransferase (LCAT) deficiency is a hereditary disease characterized by an abnormal lipid profile, corneal opacity, anemia and progressive renal disease. We report a patient with complete loss of LCAT activity due to a novel lcat gene mutation of Cys74Tyr in the lid region of LCAT protein. Esterification of cholesterol in this patient was disturbed by disruption of a substrate binding loop of Cys50-Cys74 in LCAT protein. She had progressive renal dysfunction, proteinuria, corneal opacity, anemia and an abnormal lipid profile. Her serum lipids showed a significant increase in abnormal lipoproteins at the original position in agarose gel electrophoresis and VLDL-cholesterol, and a severe decrease in serum HDL-cholesterol. Lipoprotein analyzes also revealed the presence of an abnormal midband lipoprotein, and a maturation disturbance of HDL particles. Renal function and proteinuria improved following the adoption of a fat-restricted diet and administration of an angiotensin II receptor blocker. The abnormal lipoproteins also decreased after this treatment.

Effects of valsartan on progression of kidney disease in Japanese hypertensive patients with advanced, predialysis, chronic kidney disease: Kanagawa Valsartan Trial (KVT).

Suppression of the renin-angiotensin system is known to slow progression of chronic kidney disease (CKD). However, few trials have been performed with Japanese patients. This study investigated whether the angiotensin receptor blocker (ARB) valsartan would delay the progression of kidney disease more effectively than conventional treatment in Japanese hypertensive patients with advanced, predialysis CKD. In a multicenter, randomized, open-label trial, 303 patients with hypertension and CKD with serum creatinine levels 2.0 mg dl(-1) were assigned to receive either conventional therapy plus valsartan (valsartan add-on group) or conventional therapy without ARB (control group). The primary outcome was a change in serum creatinine levels. Changes in urinary protein levels and time to onset of renal events were analyzed as secondary end points. There were no between-group differences in blood pressure during the study. Changes in serum creatinine and urinary protein levels did not differ between the groups. However, the rate of renal events, including doubling of serum creatinine levels or end-stage renal disease, was significantly lower in the valsartan add-on group than in the control group. The addition of valsartan decreased the risk by 42.6% after adjustment for baseline variables. The addition of valsartan to conventional therapy significantly slowed the rate of renal function decline and delayed the need for renal replacement therapy in Japanese hypertensive patients with advanced CKD.

Bullous pyoderma gangrenosum of the bilateral dorsal hands.

Pyoderma gangrenosum (PG) shows characteristic non-infectious ulcers that are commonly associated with systemic diseases such as inflammatory bowel diseases, myeloproliferative disorders or aortitis syndrome. The typical clinical appearance is undermining ulcers with reddish and irregular borders on the legs. As PG has these notable signs, the diagnosis is relatively easy and its treatment depends on the severity of underlying complications. We report a case of a 60-year-old Japanese man, diagnosed with bullous PG, who also had been suffering from myeloperoxidase antineutrophil cytoplasmic antibody-positive microscopic polyangiitis and pulmonary aspergillosis. This case displayed soft whitish ulcers that existed on the rough ulcer base, with irregular borders, on his bilateral dorsal hands. Initially, it seemed to be cutaneous secondary aspergillosis because the host was already infected with pulmonary aspergillosis in both lungs. The differential diagnosis of PG from aspergillosis was from the sterile bullae or neutrophilic bullae on his right forearm, which evolved into ulcers in a few days. This case was finally diagnosed as bullous PG and a topical glucocorticoid was very effective to epithelize the ulcers in 2-3 weeks.

Antigen-binding abilities of anti-nephrin antibody are prescribed by signal sequence of expression vector in genetic immunization.

BACKGROUND: Nephrin is an essential protein for maintaining the normal structure of podocyte foot processes and the glomerular filtration barrier. To analyze the mechanism of proteinuria and nephrotic syndrome, we previously reported on a new method of producing polyclonal anti-nephrin antibody by genetic immunization. In the present paper, we investigate the effect of signal peptide sequence cDNA on the characteristics of polyclonal anti-nephrin antibodies induced by genetic immunization. METHODS: Five fragments of nephrin cDNA with or without signal peptide sequence were inserted into the pTARGET™ vector. Rats were immunized with these vectors by the gene gun method. Sera obtained from rats at 14 weeks following immunization were analyzed by Western blotting, immunoprecipitation, flow cytometry and immunohistochemistry. RESULTS: Four different antibodies induced by cDNA encoding nephrin protein fragments without signal peptide showed antigen site-specific binding to fragmented glycosylation-disturbed nephrin proteins. These antibodies also reacted to a glycosylation-disturbed full-length nephrin protein (inhibited by tunicamycin), but did not react to either a native nephrin protein or a fully glycosylated conformational nephrin protein. Four different antibodies induced by cDNA encoding nephrin fragments with signal peptide showed an antigen site-specific binding to glycosylation-disturbed nephrin protein fragments. In addition, these antibodies reacted to both a native nephrin protein and a full-length glycosylated conformational nephrin protein. CONCLUSIONS: The absence of signal peptide sequence cDNA in the expression vector produced antibodies specific for glycosylation-disturbed proteins, while its presence produced antibodies that bound to native or fully glycosylated conformational protein.

[Irradiation for invasive malignant thymoma led a remission of refractory minimal change nephrotic syndrome: a case report].

A 46-year-old man was diagnosed as malignant thymoma, and was treated with chemotherapy and radiotherapy in 2003. On June 2004, he had edema of his legs and nephrotic syndrome (NS). As renal biopsy revealed a minor glomerular abnormality, he was diagnosed as minimal change nephrotic syndrome (MCNS). Intravenous steroid therapy of 500 mg/day for 3 days, following oral administration of 15 mg/day prednisolone and 75 mg cyclosporine twice a day was taken from July 2004. On July 2005, he went into remission of NS with 0.6 g/day proteinuria. On January 2008, NS relapsed with left pleural effusion. Chest CT and a biopsy specimen from left pleural mass lesion revealed the pleural invasion of malignant thymoma. Sixty Gray radiotherapy diminished the pleural metastatic lesion and also improved proteinuria from 6.6 g/day to 0.4 g/day. Though there have been a few case reports of MCNS concomitant with malignant thymoma, this is the first report that radiotherapy for metastatic malignant thymoma improved NS while diminishing the tumor.