Complete remission of primary membranous nephropathy following hepatitis E infection.

Primary membranous nephropathy (PMN) is a major cause of nephrotic syndrome in adults. Studies have shown that one-third of PMN cases undergo spontaneous remission, among which are some cases of infection-related complete remission. Herein, we report the case of a 57-year-old man who achieved complete remission of PMN shortly after the onset of acute hepatitis E infection. At the age of 55 years, the patient developed a nephrotic syndrome, and renal biopsy revealed membranous nephropathy, Ehrenreich-Churg stage 1. Treatment with prednisolone (PSL) reduced urinary protein from 7.8 g/gCre to approximately 1 g/gCre but did not lead to complete remission. However, 7 months after starting treatment, he developed an acute hepatitis E infection after consuming wild boar meat. Immediately after the onset of acute hepatitis E, the patient's urinary protein levels decreased to < 0.3 g/gCre. The PSL dose was subsequently reduced and discontinued after 2 years and 8 months, and complete remission was maintained thereafter. We considered that an increase in the number of regulatory T cells (Tregs) caused by acute hepatitis E infection was associated with PMN remission in this patient.

Long-term outcomes of anterior chest wall arteriovenous graft with polyurethane.

BACKGROUND: Anterior chest wall arteriovenous graft (ACWAVG) is one option for haemodialysis patients when vessels of the upper extremities become exhausted. We report here the long-term outcomes of ACWAVG with polyurethane. METHODS: From April 2005 to October 2015, nine ACWAVGs with polyurethane grafts were created. We observed patients until April 2019 and evaluated graft patency, interval from operation to first cannulation, and numbers of interventions and complications. RESULTS: Primary patency rate and secondary patency rate of 6, 12 and 24 months were 55.3%, 33.3%, 33.3% and 77.8%, 55.6%, 55.6% respectively. Mean interval from operation to first cannulation was 3 days. Infection rate and kinking formation rate were slightly higher than previous reports of ACWAVGs with expanded polytetrafluoroethylene (ePTFE). However, one patient was able to keep using a single graft for 166 months with multiple interventions. CONCLUSIONS: Slight disadvantage are seen with patency rate and complication rate in polyurethane ACWAVG compare to ePTFE. However, when early cannulation is required, polyurethane is worth to consider for creating ACWAVG.

Glomerulopathy with distinctive fibrillar deposits but lacking glomerular deposition of type III collagen.

A 62-year-old woman with nephrotic syndrome underwent a renal biopsy. Under light microscopy, the biopsy findings included lobulation and enlargement of glomeruli, occasional thickening of glomerular capillary walls, and narrowing of the capillary lumen by swollen endothelial cells. Congo red staining was negative for amyloid. No significant intraglomerular fibrin deposition was found by phosphotungstic acid hematoxylin staining. Immunofluorescence microscopy showed no deposition of immunoglobulin G, A, or M; no κ or λ light chains; and no C3 or C1q. Electron microscopy revealed distinctive subendothelial and mesangial fibrillar deposits, mesangial cell interposition, and swelling and vacuolization of endothelial cells resulting in capillary lumen narrowing. Although some curvilinear fibrillar deposits mimicked the bundles of type III collagen fibers seen in collagenofibrotic glomerulopathy, neither glomerular deposition of type III collagen nor elevation of serum procollagen III peptide was noted. This glomerulopathy does not fulfill any known disease entities with non-amyloid non-immunoglobulin-derived organized glomerular deposits.

Acute heart failure due to chronic juxtarenal aortic occlusion in a patient with antiphospholipid antibody syndrome.

Abdominal aortic occlusions are rare, but occasionally life threatening. A 48-year-old man was hospitalized due to acute heart failure accompanied by acute kidney injury (AKI). Abdominal ultrasound revealed deteriorating blood flow in the bilateral renal arteries. Subsequent abdominal aortography showed abdominal aortic occlusion just below the right renal artery and an occluded left renal artery. Dilated superior and inferior mesenteric arteries functioning as collateral feeding arteries suggested chronic occlusion. A hypercoagulation workup led to a diagnosis of antiphospholipid antibody syndrome (APS). This case report describes rare chronic juxtarenal abdominal occlusion in a patient with APS. .

Adjusted Anion Gap Is Associated with Glomerular Filtration Rate Decline in Chronic Kidney Disease.

BACKGROUND: Metabolic acidosis is known to accelerate the progression of chronic kidney disease (CKD). However, whether undetermined anions as indicated by the adjusted anion gap (aAG) are associated with estimated glomerular filtration rate (eGFR) decline in patients with CKD is unclear. METHODS: Data from 42 patients with CKD (baseline eGFR, 7.1-52.0 ml/min/ 1.73 m2) without massive proteinuria (urinary protein-creatinine ratio, UPCR <3.5) were retrospectively analyzed. aAG was calculated from serum sodium, serum chloride, serum bicarbonate, serum albumin, serum potassium, serum calcium and serum phosphate. The association between the percentage of the 6-month change of eGFR (%ΔeGFR/6m) and aAG was examined. RESULTS: The mean baseline eGFR was 27.5 ± 11.1 ml/min/1.73 m2 and the mean %ΔeGFR/6m was 13.8 ± 10.3. UPCR and aAG were 1.13 ± 0.93 and 9.48 ± 1.88, respectively. %ΔeGFR/6m was associated with aAG (r = 0.438, p < 0.005), but not with UPCR (r = 0.194, p = 0.218). In multivariate linear regression analyses, aAG remained significantly associated with %ΔeGFR/6m (ß = 0.45, p < 0.01) after controlling for age, baseline eGFR, UPCR and HCO3- concentration. CONCLUSION: These data suggest that aAG appears to be associated with the progression of CKD. aAG might be an independent predictor of CKD progression.

Dephosphorylated Ser985 of c-Met is associated with acquired resistance to rechallenge injury in rats that had recovered from uranyl acetate-induced subclinical renal damage.

BACKGROUND: We previously reported that rats that had recovered from mild proximal tubule (PT) injury induced by a sub-toxic dose of uranyl acetate (UA) showed partial resistance to a subsequent nephrotoxic dose of UA in association with reduced renal dysfunction and accelerated PT proliferation. We demonstrated that this resistance may involve hepatocyte growth factor (HGF)/c-Met signaling. Here, we examined whether primary cultured tubular cells derived from this model had acquired sensitivity to HGF. METHODS: Tubular cells were isolated by collagenase digestion from rat kidneys after recovery from UA-induced mild PT injury and were cultured for 48 h. Their survival and proliferation were examined using the MTS assay/5-bromo-2'-deoxyuridine labeling or MTS assay, respectively, and their migration was assayed using wound-healing and cell scattering assays, with/without HGF. HGF/c-Met signaling was assayed using phospho-specific antibodies. RESULTS: HGF-stimulated cultured tubular cells from UA-treated rats showed better survival after UA exposure and higher proliferation and migration than cells from vehicle-treated rats. Furthermore, HGF induced higher phosphorylation of c-Met (Tyr1234/1235) and of its major downstream signals (AKT and extracellular signal-regulated kinase 1/2) with maintained dephosphorylation of Ser985 as a negative regulator of HGF/c-Met signaling in the tubular cells of UA-treated rats compared to those of vehicle-treated rats. Immunohistochemically, dephosphorylated Ser985 was confirmed in PT cells in vivo. CONCLUSIONS: These results suggest that elevated sensitivity to HGF, via dephosphorylated Ser985 of c-Met of tubular cells that had recovered from mild tubular injury, may be associated with cytoprotection, accelerated proliferation and migration.

The amelioration of renal damage in Skp2-deficient mice canceled by p27 Kip1 deficiency in Skp2-/- p27-/- mice.

SCF-Skp2 E3 ubiquitin ligase (Skp2 hereafter) targets several cell cycle regulatory proteins for degradation via the ubiquitin-dependent pathway. However, the target-specific physiological functions of Skp2 have not been fully elucidated in kidney diseases. We previously reported an increase in Skp2 in progressive nephropathy and amelioration of unilateral ureteral obstruction (UUO) renal injury associated with renal accumulation of p27 in Skp2(-/-) mice. However, it remains unclear whether the amelioration of renal injury in Skp2(-/-) mice is solely caused by p27 accumulation, since Skp2 targets several other proteins. Using Skp2(-/-)p27(-/-) mice, we investigated whether Skp2 specifically targets p27 in the progressive nephropathy mediated by UUO. In contrast to the marked suppression of UUO renal injury in Skp2(-/-) mice, progression of tubular dilatation associated with tubular epithelial cell proliferation and tubulointerstitial fibrosis with increased expression of collagen and α-smooth muscle actin were observed in the obstructed kidneys in Skp2(-/-)p27(-/-) mice. No significant increases in other Skp2 target proteins including p57, p130, TOB1, cyclin A and cyclin D1 were noted in the UUO kidney in Skp2(-/-) mice, while p21, c-Myc, b-Myb and cyclin E were slightly increased. Contrary to the ameliorated UUO renal injure by Skp2-deficiency, the amelioration was canceled by the additional p27-deficiency in Skp2(-/-)p27(-/-) mice. These findings suggest a pathogenic role of the reduction in p27 targeted by Skp2 in the progression of nephropathy in UUO mice.

Enhanced intrarenal receptor-mediated prorenin activation in chronic progressive anti-thymocyte serum nephritis rats on high salt intake.

Despite suppression of the circulating renin-angiotensin system (RAS), high salt intake (HSI) aggravates kidney injury in chronic kidney disease. To elucidate the effect of HSI on intrarenal RAS, we investigated the levels of intrarenal prorenin, renin, (pro)renin receptor (PRR), receptor-mediated prorenin activation, and ANG II in chronic anti-thymocyte serum (ATS) nephritic rats on HSI. Kidney fibrosis grew more severe in the nephritic rats on HSI than normal salt intake. Despite suppression of plasma renin and ANG II, marked increases in tubular prorenin and renin proteins without concomitant rises in renin mRNA, non-proteolytically activated prorenin, and ANG II were noted in the nephritic rats on HSI. Redistribution of PRR from the cytoplasm to the apical membrane, along with elevated non-proteolytically activated prorenin and ANG II, was observed in the collecting ducts and connecting tubules in the nephritic rats on HSI. Olmesartan decreased cortical prorenin, non-proteolytically activated prorenin and ANG II, and apical membranous PRR in the collecting ducts and connecting tubules, and attenuated the renal lesions. Cell surface trafficking of PRR was enhanced by ANG II and was suppressed by olmesartan in Madin-Darby canine kidney cells. These data suggest the involvement of the ANG II-dependent increase in apical membrane PRR in the augmentation of intrarenal binding of prorenin and renin, followed by nonproteolytic activation of prorenin, enhancement of renin catalytic activity, ANG II generation, and progression of kidney fibrosis in the nephritic rat kidneys on HSI. The origin of the increased tubular prorenin and renin remains to be clarified. Further studies measuring the urinary prorenin and renin are needed.

Up-regulation of Cks1 and Skp2 with TNFα/NF-κB signaling in chronic progressive nephropathy.

The cyclin-dependent kinase (CDK) inhibitor p27 level is associated with progression of renal damage. We previously reported that mRNA of Skp2, a component of Skp/Cullin/F-box (SCF)-ubiquitin ligase which targets to p27, was increased in unilateral ureteral obstructive kidneys in mice and that the nephritis was attenuated in Skp2-deficient mice. However, the details have not been fully clarified. Here, we found that not only Skp2 but also cdc kinase subunit 1 (Cks1), an essential cofactor for the SCF-Skp2 ubiquitin ligase in targeting p27, was increased in another chronic progressive model, anti-thymocyte serum (ATS) rat nephropathy. After induction of ATS nephropathy, Skp2(+) /Cks1(+) /Ki67(+) tubular epithelial cell numbers increased, and p27(+) tubular epithelial cells decreased transiently. Moreover, we found that TNFα was involved in expression of both Skp2 and Cks1 in NRK cell line as well as the in ATS nephropathy. Nuclear accumulations of NF-κB subunits RelB and p52 were increased in the tubular epithelial cells of the nephritic kidney. Both Skp2 and Cks1 were colocalized with RelB in these cells. These data suggest that both Skp2 and Cks1 are up-regulated by the TNFα-RelB/p52 pathway in the early stages of renal damage and are collaboratively involved in down-regulation of p27 in proliferative tubular dilation and the progression of chronic nephropathy.

A case of hypokalemia-induced fatal arrhythmia caused by indapamide in an anorexic elderly patient.

An 84-year-old man was referred to our hospital for atrioventricular block and severe hypokalemia. He had been treated for hypertension since 2007 with indapamide, a thiazide-like diuretic. His laboratory data had not been tested for a long time. One week before his first visit, he suffered from a common cold and anorexia. He was admitted to our hospital because his electrocardiogram showed ventricular flutter, and pulmonary arrest occurred at the time of his visit. Cardiopulmonary resuscitation was successfully performed. Hypokalemia (K, 1.7 mEq/L) was considered as the cause of acute cardiopulmonary failure. His oral intake of potassium decreased, but potassium loss from the kidney persisted (urinary potassium, 14.0 mEq/L; transtubular potassium gradient, 5.00). These results suggested that although hypokalemia was suspected to have been present for a long time due to indapamide, severe hypokalemia was induced during the period of anorexia. After discontinuation of indapamide and intravenous administration of potassium L: -aspartate for potassium supplementation, the patient's serum potassium levels increased and his general condition improved. Although it is well known that hypokalemia is caused by indapamide, the incidence is not frequent and if observed is not severe. However, we experienced an unusual case of hypokalemia-induced fatal arrhythmia caused by indapamide. Hence, the serum potassium concentration of patients under the drug, especially anorexic elderly patients, should be monitored.

Acquired resistance to rechallenge injury in rats that recovered from mild renal damage induced by uranyl acetate: accelerated proliferation and hepatocyte growth factor/c-Met axis.

BACKGROUND: Rats that recovered from mild proximal tubule (PT) injury without renal dysfunction by subtoxic insult, developed partial resistance to subsequent nephrotoxic insult. This partial resistance was associated with reduced renal dysfunction and accelerated PT cell proliferation compared with vehicle treatment as the first insult. Here we assessed the role and potential mechanisms of accelerated PT proliferation in this acquired resistance model. METHODS: Rats at 14 days after recovering from prior mild renal damage induced by 0.2 mg/kg uranyl acetate (UA) (subtoxic dose) were rechallenged with 4 mg/kg UA (nephrotoxic dose) to establish the acquired resistance model. Cell cycle was inhibited by colchicine to examine the contribution of accelerated PT cell proliferation evaluated by in vivo bromodeoxyuridine (BrdU) labeling on acquired resistance to subsequent nephrotoxic insult. Hepatocyte growth factor (HGF)/c-Met axis and other related factors of cell cycle were analyzed. RESULTS: The acquired resistance to rechallenge injury with nephrotoxic dose of UA in rats recovered from mild renal injury was associated with an earlier increase in BrdU-positive PT cells, accelerated upregulation of HGF mRNA, c-Met mRNA/protein, cyclin D1, phospho-Rb and an earlier phenotypic change of PT cells. Colchicine inhibited PT cell proliferation, reduced the upregulated cyclin D1 and phospho-Rb in the kidney, completely abolishing acquired resistance. CONCLUSIONS: Cell cycle progression with upregulated renal HGF/c-Met axis may contribute to the accelerated recovery from acute renal failure in rats that recovered from prior mild renal damage, followed by nephrotoxic insult, resulting in partial acquired resistance.

A case presenting with rapid renal damage caused by immunoglobulin D lambda-type multiple myeloma accompanied by granular lymphocyte proliferative disorder.

A 69-year-old man was referred to our hospital for severe anemia. The atypical lymphocyte count, including granular lymphocytes, was 2,750/µL. Lymphocyte surface marker analysis showed CD3+, CD5+, CD16+, and CD56+ cells. Mixed T cell- and natural killer cell-type granular lymphocyte proliferative disorder (GLPD) was diagnosed. Because his serum creatinine levels deteriorated rapidly over the next 3 months, from 0.96 to 3.27 mg/dL, he was admitted to our hospital. The serum levels of immunoglobulins (Ig) other than IgD had decreased, and monoclonal protein was detected in the gamma-globulin region. Immunoelectrophoresis revealed IgD and lambda (λ) proteins in the serum and λ-type Bence-Jones protein in the urine. Renal biopsy examination revealed widespread tubular atrophy and interstitial fibrosis, and cast formation with λ protein deposits in tubular lumens, indicating cast nephropathy. These results indicated that the rapid renal damage was caused by IgD λ-type multiple myeloma accompanied by GLPD. The clinical course of GLPD is not usually aggressive and the findings of physical examinations are not significant. GLPD is usually associated with cytopenia (neutropenia or anemia), viral infections, collagen diseases, neoplasms such as malignant lymphoma, or chronic infections. To date, there are only 2 case reports of GLPD accompanied by multiple myeloma but without renal function or renal histological findings. When the clinical course of GLPD is aggressive and is accompanied with rapid renal damage, multiple myeloma should be considered as a complication.

Cisplatin induces Sirt1 in association with histone deacetylation and increased Werner syndrome protein in the kidney.

BACKGROUND: Sirt1, a mammalian homolog of silent information regulator 2 (Sir2), is the founding member of class III histone deacetylase (HDAC). METHODS: In this study, we examined whether Sirt1 is involved in the modification of acetylated histone H3, acetylated p53 and Werner syndrome protein (WRN), which is stabilized by Sirt1-mediated deacetylation, in cisplatin (CDDP)-induced acute renal failure (ARF) in rats. RESULTS: Administration of CDDP (5 mg/kg body weight) caused an increase in the Sirt1 protein level by 6 h; this increase peaked at day 5 and declined until day 14. Sirt1 was induced to a greater extent in rats with severe ARF. In contrast, HDAC3 and HDAC5 were not induced within 24 h after CDDP administration. The level of acetylated histone H3 in the kidney decreased early, i.e., at 6 h, and was minimal at day 5, after which the level gradually increased by day 14. CDDP marginally induced acetylated p53 within 24 h after administration. Increased WRN also became evident at 6 h, and continued to be upregulated until day 5, accompanied by an increase in proliferating cell nuclear antigen (PCNA). Transfection of Sirt1 to human embryonic kidney 293 cells mitigated the CDDP-induced cellular damage. CONCLUSIONS: These findings collectively suggest that CDDP increases the level of Sirt1 protein in the kidneys in association with histone H3 deacetylation and increased WRN and PCNA production. The induced Sirt1 may work defensively to mitigate CDDP-induced tubular damage by inactivating core histone transcriptionally, and by repairing DNA damage.

A case with significant proteinuria caused by secreted protein from urothelial carcinoma.

58-year-old female was admitted to our hospital complaining isolated proteinuria of 1.7 g/day. Abdominal echography showed right-sided unilateral hydronephrosis, and computed tomography pointed out a tumor of the right renal pelvis, suggesting cancer of renal pelvis. The right nephroureterectomy was carried out. Pathological diagnosis was urothelial carcinoma. Renal tissue revealed no apparent glomerulopathy with tubular atrophy, interstitial fibrosis, and mildly-to-moderately interstitial mononuclear cell infiltration. Immunofluorescence study showed no deposition of immunoreactanct, and electron microscopy showed almost normal glomerulus without electron dense deposit. Proteinuria disappeared within 6 days after the operation. Moderate amount of proteinuria in our patient was probably caused by secreted protein from urothelial carcinoma. This condition is rare but should be taken into account in patients with even moderate amount of proteinuria.

Hepatocyte Growth Factor stimulated cell scattering requires ERK and Cdc42-dependent tight junction disassembly.

The mechanism by which Hepatocyte Growth Factor (HGF) induces tight junction disassembly prior to cell scattering is largely unknown. Here, we show that HGF stimulates rapid loss of the TJ assembly protein Par6 from the TJ in an Erk-dependent manner. Erk activation by HGF is found to mediate the interaction of Par6 with GTP-loaded Cdc42. The Cdc42 GTPase activating protein cdGAP is shown to interact with Pkcζ at baseline and prevent Par6-Cdc42 association. Erk, by phosphorylating cdGAP at threonine776, can inhibit the GAP activity, thereby increasing Par6-Cdc42 association and TJ disassembly. Our findings reveal a novel pathway for regulating HGF signaling to the Par proteins through Erk-cdGAP, resulting in TJ disassembly and cell scattering.

Inhibition of podocyte FAK protects against proteinuria and foot process effacement.

Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that plays a critical role in cell motility. Movement and retraction of podocyte foot processes, which accompany podocyte injury, suggest focal adhesion disassembly. To understand better the mechanisms by which podocyte foot process effacement leads to proteinuria and kidney failure, we studied the function of FAK in podocytes. In murine models, glomerular injury led to activation of podocyte FAK, followed by proteinuria and foot process effacement. Both podocyte-specific deletion of FAK and pharmacologic inactivation of FAK abrogated the proteinuria and foot process effacement induced by glomerular injury. In vitro, podocytes isolated from conditional FAK knockout mice demonstrated reduced spreading and migration; pharmacologic inactivation of FAK had similar effects on wild-type podocytes. In conclusion, FAK activation regulates podocyte foot process effacement, suggesting that pharmacologic inhibition of this signaling cascade may have therapeutic potential in the setting of glomerular injury.

Immunohistochemical study of heat shock protein 27 with respect to survival and regeneration of proximal tubular cells after uranyl acetate-induced acute tubular injury in rats.

This study examined the possible role of heat shock protein 27 (HSP27) expression in the survival and regeneration of proximal tubule (PT) cells after acute tubular injury. Rats were injected with a low (0.2 mg/kg) or high (4 mg/kg) dose of uranyl acetate (UA) to induce renal injury. Renal tissues were immunostained for HSP27, focal adhesion kinase (FAK), and bromodeoxyuridine (BrdU), and stained by the TUNEL method. Low-dose UA induced focal PT depletion in the proximal three-quarters of the S3 segment. Here, cells became sporadically positive for cytoplasmic HSP27 in association with FAK+, and almost all BrdU+ early regenerating cells were positive for HSP27 from days 2 to 3. High-dose UA induced severe PT depletion in the proximal three-quarters of S3, and a small number of PT cells became positive for HSP27 as early as day 2. BrdU+, early regenerating cells were restricted to the distal quarter of S3 from days 2 to 3, with or without HSP27 staining and with FAK. In both groups, HSP+ PT cells and BrdU+ cells peaked in number at day 5. The PT cells showed reduced HSP27 accumulation by day 7 as they differentiated, but remained immunopositive for FAK. TUNEL+ apoptotic cells were immunonegative for both HSP27 and FAK. Cytoplasmic HSP27 accumulation in PT cells seems to contribute to PT survival and transition from PT cell proliferation to differentiation. When PT cells are severely impaired, distinct cells in the distal areas of S3 could undergo cell cycle progression without HSP27 accumulation.