Severe acute interstitial nephritis induced by α-glucosidase inhibitor miglitol in an elderly patient with type 2 diabetic nephropathy.

A 79-year-old male patient with type 2 diabetic nephropathy and hypertension was admitted to our hospital because of acute kidney injury with significantly elevated serum creatinine (8.12 mg/dL) and urinary ß2-microglobulin (ß2MG, 31,748 µg/L) levels. α-Glucosidase inhibitor (α-GI) miglitol, started two weeks prior to presentation, was discontinued because drug-induced acute interstitial nephritis (AIN) was suspected. Renal biopsy revealed AIN and diabetic nephropathy. The drug-induced lymphocyte stimulation test for miglitol was also positive. After the discontinuation of miglitol, the urinary ß2MG levels decreased to the normal range. This case raises the possibility that α-GI miglitol can worsen the renal function in patients with underlying renal dysfunction.

Acute Interstitial Nephritis with Glomerular Capillary IgA Deposition Following SARS-CoV-2 mRNA Vaccination.

We herein report a case of acute kidney injury (AKI) presenting as acute interstitial nephritis (AIN) after the first dose of the BNT162b2 mRNA vaccine against coronavirus disease 2019 (COVID-19). A 69-year-old man with a history of diabetes and hypertension presented with AKI 4 days after receiving the vaccine. Despite the administration of methylprednisolone pulse treatment, his renal function worsened, which prompted us to initiate temporal hemodialysis. His renal function subsequently improved, and a renal biopsy confirmed AIN and glomerular capillary IgA deposition without apparent crescents. The clinical history and histological findings suggest a relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and AIN as a rare side effect.

Pharmacological Actions of Indoxyl Sulfate and AST-120 That Should Be Recognized for the Strategic Treatment of Patients with Chronic Kidney Disease.

Although there are many uremic substances in the body, the most studied and well-known molecule that predominantly binds to plasma proteins is indoxyl sulfate (IS). Many research groups have reported IS to have toxic effects on the kidney and cardiovascular system. It is difficult to remove IS with regular hemodialysis or hemodiafiltration. On the other hand, AST-120 has the capacity to bind to indole, which is a precursor of IS in the intestinal tract and excrete it in feces. IS production in the liver is efficiently suppressed by AST-120 administration. However, large-scale clinical studies have not shown that AST-120 suppresses hard endpoints such as doubling serum creatinine, end-stage renal disease, and death. In patients with accelerated chronic kidney disease (CKD) progression, AST-120 is expected to suppress those hard renal endpoints, but only when compliance to treatment is high. It is necessary to validate the renal protective effect of AST-120, as expected from the basic study on IS, including more patients with slowly progressive CKD in a large-scale clinical study in the future.

Vasculitis and crescentic glomerulonephritis in a newly established congenic mouse strain derived from ANCA-associated vasculitis-prone SCG/Kj mice.

Lupus nephritis (LN) is the secondary glomerulonephritis (GN) involved in systemic lupus erythematosus (SLE) and a typical immune complex-type GN. Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease characterized by systemic vasculitis and pauci-immune-type crescentic glomerulonephritis (CrGN) with ANCA production. Human AAV causes death due to lung haemorrhage and end-stage renal disease, for which renal replacement therapies are necessary. The SLE/AAV overlap syndrome was recently reported in humans. The spontaneous crescentic glomerulonephritis-forming/Kinjoh (SCG/Kj) mouse is a unique model of human AAV showing production of myeloperoxidase (MPO)-ANCA. We previously discovered seven disease susceptibility quantitative trait loci (QTL) derived from SCG/Kj mice by linkage analysis. To investigate the individual functions of each QTL, and to identify AAV susceptibility genes, we introduced them into a B6/lpr background to establish SCG/Kj interval congenic mice (SICM). B6/lpr.C1scg mice, a type of SICM, exhibited the production of autoantibodies, including MPO-ANCA. The GN in B6/lpr.C1scg mice was not pauci-immune type: deposition of immunoglobulins and complement components was observed in nephritic glomeruli, similar to that in LN. The incidence of GN in female B6/lpr.C1scg mice was 100%. Granulocyte infiltration was also observed in the glomerular tuft and crescents. B6/lpr.C1scg mice also displayed vasculitis in multiple organs, most frequently the lung and kidney. Vasculitis was characterized by the infiltration of mononuclear cells to vascular walls followed by granulocyte infiltration, resembling human lupus vasculitis. The incidence of lung vasculitis was over 90% in male and female B6/lpr.C1scg mice. Blood MPO-ANCA levels were significantly associated with histopathological disease phenotypes. MPO deposition was observed in nephritic glomeruli, and granulocytes infiltrated into inflamed vessels and glomeruli. These observations suggest that the activation of granulocytes and local MPO release contribute to the pathogenesis of GN and vasculitis. As a monocongenic mouse, B6/lpr.C1scg mice show the association between murine chromosome 1 segment and autoimmunity. This strain can be used as a model of the SLE/AAV overlap syndrome, and will be useful for elucidating the mechanism of ANCA generation and the pathogenesis of CrGN and vasculitis, as well as in the search for genetic factors related to AAV.

Effects of the sodium-glucose cotransporter 2 inhibitor dapagliflozin on fluid distribution: A comparison study with furosemide and tolvaptan.

AIM: Sodium-glucose cotransporter 2 (SGLT2) inhibitors are an antihyperglycemic drug with diuretic properties. We recently reported that an SGLT2 inhibitor ameliorated extracellular fluid expansion with a transient increase in urinary Na+ excretion. However, the effects of SGLT2 inhibitors on fluid distribution in comparison to conventional diuretics remain unclear. METHODS: Forty chronic kidney disease patients with fluid retention (average estimated glomerular filtration rate 29.2 ± 3.2 mL/min per 1.73 m2 ) were divided into the SGLT2 inhibitor dapagliflozin (DAPA), loop diuretic furosemide (FR) and vasopressin V2 receptor antagonist tolvaptan (TLV). The body fluid volume was measured on days 0 and 7 using a bioimpedance analysis device. RESULTS: In all three groups, body weight was significantly and similarly decreased, and urine volume numerically increased for 7 days. Bioimpedance analysis showed that the changes in intracellular water were similar, but that there were significant changes in the extracellular water (ECW) (DAPA -8.4 ± 1.7, FR -12.5 ± 1.3, TLV -7.4 ± 1.5%, P = 0.048). As a result, the change in the ratio of ECW to total body water in the DAPA group was significantly smaller than that in the FR group, but numerically larger than that in the TLV group (DAPA -1.5 ± 0.5, FR -3.6 ± 0.5, TLV -0.5 ± 0.4%, P < 0.001). CONCLUSION: Sodium-glucose cotransporter 2 inhibitor DAPA predominantly decreased the ECW with a mild increase in urine volume, but the change in the ECW/total body water was smaller than that in patients treated with FR, and larger than that in patients treated with TLV, suggesting that the effects of SGLT2 inhibitors on fluid distribution may differ from those of conventional diuretics.

Hemolytic Uremic Syndrome: An Increasingly Recognized Public Health Problem.

A 28-year-old man was referred and admitted to our hospital due to Escherichia coli O157-mediated hemorrhagic colitis with severe thrombocytopenia. A systemic workup concluded that the patient had acute pancreatitis as well as hemolytic uremic syndrome. The patient was ultimately discharged, with his platelet count having recovered. Our case serves an illustrative example of potentially serious complications of an increasingly recognized public health problem. Systemic studies on this topic are insufficient, and we strongly recommend the further accumulation of more experiences like ours. Several diagnostic and management concerns that emerged in this case are also discussed.

Valacyclovir Neurotoxicity and Nephrotoxicity in an Elderly Patient Complicated by Hyponatremia.

A 66-year-old women with no history of renal disease was admitted due to a coma and acute kidney injury with a serum creatinine level of 7.44 mg/dL which were ascribed to valacyclovir neurotoxicity and nephrotoxicity, respectively. She had received valacyclovir at a standard dosage for the treatment of herpes zoster and was finally discharged, having fully returned to her normal baseline mental status with a recovered serum creatinine level of 0.68 mg/dL. We feel that awareness of this pathology remains a challenge for physicians and therefore strongly recommend the further accumulation of experiences similar to our own. Our experience underscores the pitfalls of administering valacyclovir to elderly patients who barely appear to have a favorable renal function. Several concerns regarding the therapeutic management, including blood purification strategies, that emerged in this case are also discussed.

Nephrotic Syndrome and a Retroperitoneal Mass: A Case Report of a Patient with Recurrent Invasive Thymoma.

A 68-year-old man was admitted to our hospital to undergo an examination for nephrotic syndrome while concurrently complicated with recurrent thymoma in the parietal pleura and retroperitoneum. He had been diagnosed with invasive thymoma and had undergone thymo-thymectomy seven years previously. Based on the renal biopsy findings, his nephrotic syndrome was ascribed to minimal change disease. He was treated with corticosteroid monotherapy, which resulted in complete remission six months later, despite the fact that the recurrent thymoma remained. The role of thymoma in the pathogenesis of paraneoplastic glomerulopathy and the therapeutic concerns that emerged in this case are also discussed.

Detection of microRNA Expression in Peritoneal Membrane of Rats Using Quantitative Real-time PCR.

MicroRNAs (miRNAs) are small noncoding RNAs that regulate messenger RNA expression post-transcriptionally. The miRNA expression profile has been investigated in various organs and tissues in rat. However, standard methods for the purification of miRNAs and detection of their expression in rat peritoneal membrane have not been well established. We have developed an effective and reliable method to purify and quantify miRNAs using quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) in rat peritoneal membrane. This protocol consists of four steps: 1) purification of peritoneal membrane sample; 2) purification of total RNA including miRNA from peritoneal membrane sample; 3) reverse transcription of miRNA to produce cDNA; and 4) qRT-PCR to detect miRNA expression. Using this protocol, we successfully determined that the expression of six miRNAs (miRNA-142-3p, miRNA-21-5p, miRNA-221-3p, miRNA-223-3p, miRNA-327, and miRNA-34a-5p) increased significantly in the peritoneal membrane of a rat peritoneal fibrosis model compared with those in control groups. This protocol can be used to study the profile of miRNA expression in the peritoneal membrane of rats in many pathological conditions.

The association between soluble intercellular adhesion molecule-1 levels in drained dialysate and peritoneal injury in peritoneal dialysis.

BACKGROUND: Chronic inflammation of the peritoneum causes peritoneal injury in patients on peritoneal dialysis. Intercellular adhesion molecule-1 and its circulating form, soluble intercellular adhesion molecule-1, play pivotal roles in inflammation. However, their role in peritoneal injury is unclear. METHODS: We measured changes in intercellular adhesion molecule-1 expression in the peritoneum of a peritoneal injury model in rats. The associations between soluble intercellular adhesion molecule-1 levels in drained dialysate and the solute transport rate (D/P-Cr and D/D0-glucose) determined by the peritoneal equilibration test, and matrix metalloproteinase-2 levels in drained dialysate were investigated in 94 peritoneal drained dialysate samples. RESULTS: Intercellular adhesion molecule-1 expression was increased in the peritoneum of rats with peritoneal injury. Soluble intercellular adhesion molecule-1 levels in drained dialysate were significantly positively correlated with D/P-Cr (r = .51, p < .01) and inversely correlated with D/D0-glucose (r = -.44, p < .01). They were also significantly positively correlated with matrix metalloproteinase-2 levels in drained dialysate (r = .86, p < .01). CONCLUSIONS: Intercellular adhesion molecule-1expression is increased in the peritoneum of a peritoneal injury model in the rat, and soluble intercellular adhesion molecule-1 levels in drained dialysate are associated with peritoneal injury in patients on peritoneal dialysis. These results suggest that soluble intercellular adhesion molecule-1 could be a novel biomarker of peritoneal injury in patients on peritoneal dialysis.

MicroRNA expression profiling in peritoneal fibrosis.

Peritoneal fibrosis (PF) is an intractable complication leading to peritoneal membrane failure in peritoneal dialysis (PD). The aim of this study was to identify microRNAs (miRNAs) involved in PF. Peritoneal tissue from a PF rat model was screened for miRNA expression using microarray analysis. The expression levels of differentially expressed miRNAs were evaluated in serum and drained dialysate and associated with peritoneal membrane functions, as measured by the peritoneal equilibrium test in 33 PD patients. Furthermore, an miRNA inhibitor (anti-miRNA-21-5p locked nucleic acid (LNA): anti-miRNA-21-LNA) was intraperitoneally injected to PF model mice to investigate its effects on PF. The initial profiling study of PF rat peritoneal tissue identified 6 miRNAs (miRNA-142-3p, miRNA-21-5p, miRNA-221-3p, miRNA-223-3p, miRNA-34a-5p, and miRNA-327) whose expression was increased more than 2-fold and no miRNAs whose expression was decreased more than half. Among them, serum levels of miRNA-21-5p, miRNA-221-3p, and miRNA-327 and drained dialysate levels of miRNA-221-3p and miRNA-34a-5p were significantly correlated with peritoneal membrane functions in PD patients. Anti-miRNA-21-LNA significantly inhibited miRNA-21-5p expression in the PF mouse peritoneum, inhibited peritoneal fibrous thickening, and maintained peritoneal membrane functions. These results suggest that several miRNAs are involved in PF and that they may be useful as novel diagnostic biomarkers and therapeutic targets for PF.

Delivery of microRNA-146a with polyethylenimine nanoparticles inhibits renal fibrosis in vivo.

Renal fibrosis is the final common pathway leading to end-stage renal disease. Although microRNA (miR) was recently shown to be involved in the development of renal fibrosis, few studies have focused on the effects on renal fibrosis of exogenous miR delivered in an in vivo therapeutic setting. The study reported here investigated the effects of miR-146a delivery using polyethylenimine nanoparticles (PEI-NPs) on renal fibrosis in vivo. PEI-NPs bearing miR-146 or control-miR (nitrogen/phosphate ratio: 6) were injected into the tail vein of a mouse model of renal fibrosis induced by unilateral ureteral obstruction. PEI-NPs bearing miR-146 significantly enhanced miR-146a expression in the obstructed kidney compared with the control group, while inhibiting the renal fibrosis area, expression of alpha-smooth muscle actin, and infiltration of F4/80-positive macrophages into the obstructed kidney. In addition, PEI-NPs bearing miR-146a inhibited the transforming growth factor beta 1-Smad and tumor necrosis factor receptor-associated factor 6-nuclear factor kappa B signaling pathways. Control-miR-PEI-NPs did not show any of these effects. These results suggest that the delivery of miR-146a attenuated renal fibrosis by inhibiting pro-fibrotic and inflammatory signaling pathways and that the delivery of appropriate miRs may be a therapeutic option for preventing renal fibrosis in vivo.

Henoch-Schönlein purpura complicated with severe gastrointestinal bleeding.

Bleeding from the gastrointestinal tract is one of the common determinants of morbidity and mortality in the ordinary clinical setting. The gastrointestinal involvement of Henoch-Schönlein purpura (HSP) has often been described as self-limiting, with no long-term morbidity. In this report, we describe our experience with a male HSP patient who presented with abdominal pain, loss of appetite and deteriorated renal function associated with nephrotic syndrome. Despite the use of aggressive immunomodulatory treatments, including corticosteroids and plasmapheresis, he developed lethal gastrointestinal hemorrhage. We believe that the accumulation of more experience with additional cases similar to ours is mandatory for the establishment of optimal management for HSP patients with severe gastrointestinal manifestations.

siRNAs targeted to Smad4 prevent renal fibrosis in vivo.

Renal fibrosis is the final common pathway leading to decreased renal function. No therapy has been established to prevent it. In order to establish a therapeutic approach and target molecule for renal fibrosis, we investigated the effects of Smad4 knockdown by siRNAs on renal fibrosis in vivo. Renal fibrosis mice were produced by single intraperitoneal injection of folic acid. siRNAs targeted to Smad4 (Smad4-siRNAs) (5 nmol) were injected into each mouse by systemic tail vein injection three times per week. Non-targeted siRNAs (control-siRNAs) were injected in the same way for a control group. The siRNAs were delivered to the interstitial fibrous area and tubules. Smad4-siRNAs significantly knocked down Smad4 expression and inhibited renal fibrosis. They also inhibited α-SMA-positive myofibroblasts. Control-siRNAs did not show these effects. The results of this study suggest that Smad4 knockdown is one of the crucial therapeutic options for the prevention of renal fibrosis in vivo.

Reasons for encounter and diagnoses of new outpatients at a small community hospital in Japan: an observational study.

PURPOSE: Although many new patients are seen at small hospitals, there are few reports of new health problems from such hospitals in Japan. Therefore, we investigated the reasons for encounter (RFE) and diagnoses of new outpatients in a small hospital to provide educational resources for teaching general practice methods. METHODS: This observational study was conducted at the Department of General Internal Medicine in a small community hospital between May 6, 2010 and March 11, 2011. We classified RFEs and diagnoses according to component 1, "Symptoms/Complaints", and component 7, "Diagnosis/Diseases", of the International Classification of Primary Care, 2nd edition (ICPC-2). We also evaluated the differences between RFEs observed and common symptoms from the guidelines Model Core Curriculum for Medical Students and Goals of Clinical Clerkship. RESULTS: We analyzed the data of 1,515 outpatients. There were 2,252 RFEs (1.49 per encounter) and 170 ICPC-2 codes. The top 30 RFE codes accounted for 80% of all RFEs and the top 55 codes accounted for 90%. There were 1,727 diagnoses and 196 ICPC-2 codes. The top 50 diagnosis codes accounted for 80% of all diagnoses, and the top 90 codes accounted for 90%. Of the 2,252 RFEs, 1,408 (62.5%) included at least one of the 36 symptoms listed in the Model Core Curriculum and 1,443 (64.1%) included at least one of the 35 symptoms in the Goals of Clinical Clerkship. On the other hand, "A91 Abnormal result investigation", "R21 Throat symptom/complaint", and "R07 Sneezing/nasal congestion", which were among the top 10 RFEs, were not included in these two guidelines. CONCLUSION: We identified the common RFEs and diagnoses at a small hospital in Japan and revealed the inconsistencies between the RFEs observed and common symptoms listed in the guidelines. Our findings can be useful in improving the general practice medical education curricula.

Purpura with ulcerative skin lesions and mixed cryoglobulinemia in a quiescent hepatitis B virus carrier.

Mixed cryoglobulinemia is occasionally seen in patients with hepatitis B virus (HBV) infection. This report presents the case of a quiescent HBV carrier who had type II mixed cryoglobulinemia, protracted purpura, ulcerative skin lesions and advanced chronic kidney disease. The cutaneous manifestations of the patient improved along with a decrease in the serum cryoglobulin and HBV-deoxyribonucleic acid levels following the initiation of oral entecavir in combination with plasmapheresis. However, the patient ultimately required prednisolone due to the limited benefits of these treatments. We also discuss various concerns regarding steroid treatment in patients with mixed cryoglobulinemia complicated by HBV infection.

Acute post-streptococcal glomerulonephritis with acute kidney injury in nephrotic syndrome with the glomerular deposition of nephritis-associated plasmin receptor antigen.

We herein report the case of a 17-year-old man who developed an increased plasma creatinine level (11.1 mg/dL) and oliguria with massive proteinuria (27.3 g/day) four weeks after an abraded wound to his right knee. The histology of the renal biopsy specimens showed diffuse endocapillary proliferative glomerulonephritis with the deposition of nephritis-associated plasmin receptor in the glomerulus. A case of acute kidney injury due to nephrotic syndrome caused by acute post-streptococcal glomerulonephritis was diagnosed. His renal function and proteinuria were improved with supportive care, including hemodialysis, without the administration of immunosuppressive agents.

Rituximab Treatment for PR3-ANCA-Positive Membranoproliferative Glomerulonephritis Associated with Adult-Onset Periodic Fever Syndrome.

We report the case of a 36-year-old Japanese woman with nephrotic syndrome due to membranoproliferative glomerulonephritis (MPGN) Type I diagnosed after a 5-year history of periodic fever syndrome (PFS). Hypocomplementemia and elevation of anti-proteinase 3 anti-neutrophil cytoplasmic autoantibody (PR3-ANCA) were observed. HIV, and hepatitis B and C serology were negative. Nephrotic syndrome and periodic fever did not respond to oral steroid and intravenous steroid pulse therapies combined with cyclosporine, dipyridamole, warfarin and losartan. We tried immunotherapy using rituximab, a human-mouse chimeric monoclonal antibody directed against the CD20 antigen on mature B cells. This therapeutic approach led to improvement of renal function and remission of nephrotic syndrome and hypocomplementemia. However, it did not have a beneficial effect on periodic fever. Suspecting adult-onset hereditary PFS, we analyzed her genetic alteration of MEFV and TNFRSF1A genes. A rare genotype in intron 6 of TNFRSF1A was revealed. The etiological relationship between periodic fever and MPGN is discussed. Rituximab is a hopeful choice of induction therapy for refractory MPGN.

Characteristics of urinary and serum soluble Klotho protein in patients with different degrees of chronic kidney disease.

BACKGROUND: Klotho is a single-pass transmembrane protein, which appears to be implicated in aging. The purpose of the present study was to characterize the relationship between the soluble Klotho level and renal function in patients with various degrees of chronic kidney disease (CKD). METHODS: The levels of soluble Klotho in the serum and urine obtained from one hundred thirty-one CKD patients were determined by a sandwich enzyme-linked immunosorbent assay system. RESULTS: The amount of urinary excreted Klotho during the 24 hr period ranged from 1.6 to 5178 ng/day (median 427 ng/day; interquartile range [IR] 56.8-1293.1), and the serum Klotho concentration ranged from 163.9 to 2123.7 pg/ml (median 759.7 pg/ml; IR 579.5-1069.1). The estimated glomerular filtration rate (eGFR) was significantly correlated with the log-transformed values of the amount of 24 hr urinary excreted Klotho (r = 0.407, p < 0.01) and the serum Klotho levels (r = 0.232, p < 0.01). However, a stepwise multiple regression analysis identified eGFR to be a variable independently associated only with the log-transformed value of the amount of 24-hr urinary excreted Klotho but not with the log-transformed serum Klotho concentration. Despite the strong correlation between random urine protein-to-creatinine ratio and the 24 hr urinary protein excretion (r = 0.834, p < 0.01), a moderate linear association was observed between the log-transformed value of the amount of 24 hr urinary excreted Klotho and that of the urinary Klotho-to-creatinine ratio (Klotho/Cr) in random urine specimens (r = 0.726, p < 0.01). CONCLUSIONS: The amount of urinary Klotho, rather than the serum Klotho levels, should be linked to the magnitude of the functioning nephrons in CKD patients. The use of random urine Klotho/Cr as a surrogate for the amount of 24-hr urinary excreted Klotho needs to be evaluated more carefully.

Promoter methylation confers kidney-specific expression of the Klotho gene.

The aging suppressor geneKlotho is predominantly expressed in the kidney irrespective of species. Because Klotho protein is an essential component of an endocrine axis that regulates renal phosphate handling, the kidney-specific expression is biologically relevant; however, little is known about its underlying mechanisms. Here we provide in vitro and in vivo evidence indicating that promoter methylation restricts the expression of the Klotho gene in the kidney. Based on evolutionary conservation and histone methylation patterns, the region up to -1200 bp was defined as a major promoter element of the human Klotho gene. This region displayed promoter activity equally in Klotho-expressing and -nonexpressing cells in transient reporter assays, but the activity was reduced to ∼20% when the constructs were integrated into the chromatin in the latter. Both endogenous and transfected Klotho promoters were 30-40% methylated in Klotho-nonexpressing cells, but unmethylated in Klotho-expressing renal tubular cells. DNA demethylating agents increased Klotho expression 1.5- to 3.0-fold in nonexpressing cells and restored the activity of silenced reporter constructs. Finally, we demonstrated that a severe hypomorphic allele of Klotho had aberrant CpG methylation in kl/kl mice. These findings might be useful in therapeutic intervention for accelerated aging and several complications caused by Klotho down-regulation.