Estimating baseline creatinine levels based on the kidney parenchymal volume.

BACKGROUND: Acute kidney injury (AKI) diagnosis often lacks a baseline serum creatinine (Cr) value. Our study aimed to create a regression equation linking kidney morphology to function in kidney donors and chronic kidney disease patients. We also sought to estimate baseline Cr in minimal change disease (MCD) patients, a common AKI-predisposing condition. METHODS: We analyzed 119 participants (mean age 60 years, 50% male, 40% donors) with CT scans, dividing them into derivation and validation groups. An equation based on kidney parenchymal volume (PV) was developed in the derivation group and validated in the validation group. We estimated baseline Cr in 43 MCD patients (mean age 45 years, 61% male) using the PV-based equation and compared with their 6 month post-MCD onset Cr values. RESULTS: In the derivation group, the equation for the estimated glomerular filtration rate (eGFR) was: eGFR (mL/min/1.73m2) = 0.375 × PV (cm3) + (- 0.395) × age (years) + (- 2.93) × male sex + (- 13.3) × hypertension + (- 14.0) × diabetes + (- 0.210) × height (cm) + 82.0 (intercept). In the validation group, the eGFR and estimated Cr values correlated well with the measured values (r = 0.46, p = 0.01; r = 0.51, p = 0.004, respectively). In the MCD group, the baseline Cr values were significantly correlated with the estimated baseline Cr values (r = 0.52, p < 0.001), effectively diagnosing AKI (kappa = 0.76, p < 0.001). CONCLUSIONS: The PV-based regression equation established in this study holds promise for estimating baseline Cr values and diagnosing AKI in patients with MCD. Further validation in diverse AKI populations is warranted.

Fractional excretion of total protein predicts renal prognosis in Japanese patients with primary membranous nephropathy.

Background: Primary membranous nephropathy (pMN) is one of the most common types of glomerulonephritis, with a third of patients progressing to renal insufficiency. Various prognostic factors have been reported, of which urinary protein and renal function are the most critical parameters. Fractional excretion of total protein (FETP) indicates protein leakage that accounts for creatinine kinetics and serum protein levels. In this study, we investigated the association between FETP and renal prognosis in pMN. Methods: We retrospectively identified 150 patients with pMN. FETP was calculated as follows: (serum creatinine × urine protein)/(serum protein × urine creatinine) %. We divided the patients into three groups according to FETP values and compared the clinicopathological findings. The primary outcome was an estimated glomerular filtration rate (eGFR) decrease of ≥30% from the baseline level. Results: FETP was associated with urinary protein and renal function, Ehrenreich and Churg stage, and global glomerulosclerosis. The primary outcome was observed in 38 patients (25.3%), and the frequency of the primary outcome was higher in the high FETP group (P = .001). FETP is higher than protein-creatinine ratio (PCR) in the area under the curve. In the multivariate analysis adjusted for age, eGFR, PCR and treatment, FETP was significantly associated with primary outcome (adjusted hazard ratio, 8.19; P = .019). Conclusions: FETP is a valuable indicator that can reflect the pathophysiology and is more useful than PCR as a predictor of renal prognosis in patients with Japanese pMN.

A Case of Acute Necrotizing Encephalopathy With Multiple Organ Failure Following COVID-19.

Neurological complications are frequent non-respiratory complications associated with coronavirus disease 2019 (COVID-19), and acute encephalopathy (AE) has been reported to occur in 2.2% of patients. Among many phenotypes of AEs, acute necrotizing encephalopathy (ANE) is associated with multiple organ failure (MOF), leading to severe neurological morbidity and mortality. A previously healthy seven-year-old girl presented with a one-day history of fever followed by 12 hours of vomiting and altered consciousness. On arrival, the patient was in shock. Blood tests revealed severe acute liver failure and kidney injury, accompanied by coagulopathy. The serum interleukin-6 levels were also elevated. PCR testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was positive. A head CT scan showed heterogeneous low-density areas in the bilateral thalamus, without brainstem involvement. She was diagnosed as ANE complicated with MOF (ANE severity score = 6). Intravenous methylprednisolone and therapeutic plasma exchange (TPE) were initiated with neurocritical care. After the introduction of TPE, hemodynamics improved rapidly, followed by gradual improvement in neurological manifestations. Upon follow-up after two months, no neurological or systemic sequelae were noted. Although further studies are needed, our case suggests that early immunomodulatory therapy and TPE may have contributed to the improvement in ANE and MOF associated with COVID-19.

Clinicopathological prognostic stratification for proteinuria and kidney survival in IgA nephropathy: a Japanese prospective cohort study.

Background: We require a clinicopathological risk stratification method for immunoglobulin A nephropathy (IgAN) to predict kidney outcomes. We examined a renal failure risk group (RF-RG) classification system created following a prior multicentre, retrospective study to determine if RF-RG could predict kidney outcomes. Methods: We collected data from Japanese patients with IgAN registered between 1 April 2005 and 31 August 2015. The primary outcome was a composite 50% increase in serum creatinine from baseline or dialysis induction. The secondary outcomes were times to proteinuria remission (ProR) and haematuria remission (HemR). Results: The enrolled 991 patients from 44 facilities were followed for a median of 5.5 years (interquartile range 2.5-7.5), during which 87 composite events (8.8%) occurred. RF-RG was significantly associated with the primary outcome {hazard ratio [HR] II 2.78 [95% confidence interval (CI) 1.12-6.93], III 7.15 (2.90-17.6), IV 33.4 (14.1-79.0), I as a reference, P < .001}.The discrimination performance was good [C-statistic 0.81 (95% CI 0.76-0.86)] and the time-dependent C-statistics exceeded 0.8 over 10 years. Among the 764 patients with proteinuria and 879 patients with haematuria at baseline, 515 and 645 patients showed ProR and HemR, respectively. ProR was significantly less frequent in patients with advanced disease [subdistribution HR: II 0.79 (95% CI 0.67-0.94), III 0.53 (0.41-0.66), IV 0.15 (0.09-0.23), I as a reference, P < .001]. We also observed an association between HemR and RF-RG. Conclusions: RF-RG demonstrated good predictive ability for kidney outcomes.

Early growth response 1 as a podocyte injury marker in human glomerular diseases.

Background: In human glomerular diseases, visualizing podocyte injury is desirable since podocytes do not regenerate and podocyte injury leads to podocyte loss. Herein, we investigated the utility of immunostaining for early growth response 1 (EGR1), which is expressed in injured podocytes from the early stages of injury in animal experiments, as a podocyte injury marker in human glomerular diseases. Methods: This study included 102 patients with biopsy-proven glomerular diseases between 2018 and 2021. The proportion of EGR1 expression in podocytes (%EGR1pod) was analyzed in relation to clinical and histopathological features, including glomerular and urinary podocyte-specific markers. Results: %EGR1pod correlated significantly with the urinary protein:creatinine ratio, urinary nephrin and podocin mRNA levels, and glomerular podocin staining (rho = 0.361, 0.514, 0.487 and -0.417, respectively; adjusted P = .002, <.001, <.001 and <.001, respectively). Additionally, %EGR1pod correlated with cellular/fibrocellular crescents (rho = 0.479, adjusted P <.001). %EGR1pod was high in patients with glomerulonephritis, such as immunoglobulin A nephropathy (IgAN), lupus nephritis and antineutrophil cytoplasmic antibody-associated glomerulonephritis, and in those with podocytopathies, such as membranous nephropathy and primary focal segmental glomerulosclerosis, while %EGR1pod was low in patients with minimal change disease. In a subgroup analysis of IgAN, %EGR1pod was higher in Oxford C1 patients than in C0 patients. However, unexpectedly, patients with higher %EGR1pod were more prone to attain proteinuria remission, suggesting that EGR1 in the context of IgAN reflects reversible early injury. Conclusions: Our findings indicate that EGR1 is a promising potential marker for identifying active early podocyte injury in human glomerular diseases.

Associations of corticosteroid therapy and tonsillectomy with kidney survival in a multicenter prospective study for IgA nephropathy.

Efficacy of systemic corticosteroid therapy (CS) for long-term kidney survival in patients with IgA nephropathy (IgAN) is controversial. Therefore, prospective studies evaluating targeted therapies to lymphatic tissues in mucosal immune system responsible for production of nephritogenic IgA have been desired worldwide. Here, we aimed to evaluate the associations of CS and combination therapy of CS and tonsillectomy (CS + Tx) with kidney survival, using database from a nationwide multicenter prospective cohort study on IgAN. Primary outcome was a 50% increase in serum creatinine from baseline or dialysis induction. The analysis included 941 patients (CS/CS + Tx/non-CS 239/364/338), 85 (9.0%) of whom reached outcomes during median follow-up of 5.5 (interquartile range 2.0-8.0) years. On overlap weighting analysis with balanced baseline characteristics, CS and CS + Tx were associated with lower risk of kidney events when compared with non-CS (hazard ratio [HR] 0.51, 95% confidence interval [CI] 0.29-0.88 and HR 0.20, 95%CI 0.09-0.44, respectively). Notably, when compared with the CS, CS + Tx was associated with a lower risk of kidney events (HR 0.40, 95%CI 0.18-0.91). Present study demonstrated, keeping with favorable association of systemic CS with kidney survival, concurrent tonsillectomy as one of targeted interventions to lymphatic tissues may provide additional improvement to kidney survival in patients with IgAN.

Early Recurrence of Immunoglobulin A Nephropathy after Kidney Transplantation in a Patient with Down Syndrome.

A 39-year-old male kidney transplant recipient with Down syndrome (DS) was admitted to our hospital for biopsy. He had proteinuria at age 9, was diagnosed with immunoglobulin A nephropathy (IgAN) at age 22, had a tonsillectomy at age 35, and underwent ABO-compatible kidney transplantation (from his mother) at age 36. His serum creatinine was stable at 2.21 mg/dL 3 months after the kidney transplant, and his urine protein was 0.11 g/day. A protocol biopsy was performed 7 months after the kidney transplant, and there was suspicion of early recurrence of IgAN. One year after the transplant, urine erythrocytes were elevated and proteinuria was 0.41 g/day; at 3 years and 5 months after the kidney transplant, hematuria was evident along with proteinuria (0.74 g/day). Therefore, an episode biopsy was performed. A total of 23 glomeruli were obtained, four of which exhibited global sclerosis; three others showed intra- and extracapillary proliferative glomerulonephritis compatible with IgAN recurrence. Here, we report a rare case of early recurrence of IgAN with disease progression despite tonsillectomy in a patient with DS.

Non-dipping pulse rate and chronic changes of the kidney in patients with chronic kidney disease.

Introduction: An insufficient decrease in nocturnal pulse rate (PR), non-dipping PR, reflects autonomic imbalance and is associated with cardiovascular events and all-cause mortality. We aimed to investigate the clinical and microanatomical structural findings associated with the non-dipping PR status in patients with chronic kidney disease (CKD). Methods: This cross-sectional study included 135 patients who underwent ambulatory blood pressure monitoring and kidney biopsy concurrently at our institution between 2016 and 2019. Non-dipping PR status was defined as (daytime PR-nighttime PR)/daytime PR <0.1. We compared clinical parameters and microstructural changes in the kidney between patients with and without non-dipping PR, including 24 h proteinuria, glomerular volume, and Mayo Clinic/Renal Pathology Society Chronicity Score. Results: The median age was 51 years (interquartile range: 35-63), 54% of which were male, and the median estimated glomerular filtration rate was 53.0 (30.0-75.0) mL/min/1.73 m2. Non-dipping PR status was observed in 39 patients. Patients with non-dipping PR were older and had worse kidney function, higher blood pressure, greater prevalence of dyslipidemia, lower hemoglobin levels, and a larger amount of urinary protein excretion than patients with dipping PR. Patients with non-dipping PR had more severe glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriosclerosis. In the multivariable analysis, the severe chronic changes of the kidney were associated with non-dipping PR status after adjusting for age, sex, and other clinical parameters (odds ratio = 20.8; 95% confidence interval, 2.82-153; P = 0.003). Conclusion: This study is the first to indicate that non-dipping PR is significantly associated with chronic microanatomical changes in the kidneys of patients with CKD.

Structural modeling for Oxford histological classifications of immunoglobulin A nephropathy.

In immunoglobulin A nephropathy (IgAN), Cox regression analysis can select independent prognostic variables for renal functional decline (RFD). However, the correlation of the selected histological variables with clinical and/or treatment variables is unknown, thereby making histology-based treatment decisions unreliable. We prospectively followed 946 Japanese patients with IgAN for a median of 66 mo. and applied structural equation modeling (SEM) to identify direct and indirect effects of histological variables on RFD as a regression line of estimated glomerular filtration rate (eGFR) via clinical variables including amount of proteinuria, eGFR, mean arterial pressure (MAP) at biopsy, and treatment variables such as steroid therapy with/without tonsillectomy (ST) and renin-angiotensin system blocker (RASB). Multi-layered correlations between the variables and RFD were identified by multivariate linear regression analysis and the model's goodness of fit was confirmed. Only tubular atrophy/interstitial fibrosis (T) had an accelerative direct effect on RFD, while endocapillary hypercellularity and active crescent (C) had an attenuating indirect effect via ST. Segmental sclerosis (S) had an attenuating indirect effect via eGFR and mesangial hypercellularity (M) had accelerative indirect effect for RFD via proteinuria. Moreover, M and C had accelerative indirect effect via proteinuria, which can be controlled by ST. However, both T and S had additional indirect accelerative effects via eGFR or MAP at biopsy, which cannot be controlled by ST. SEM identified a systemic path links between histological variables and RFD via dependent clinical and/or treatment variables. These findings lead to clinically applicable novel methodologies that can contribute to predict treatment outcomes using the Oxford classifications.

Two entities in pulmonary nodules of a diabetic patient receiving corticosteroid therapy for bullous pemphigoid: an autopsy case report.

BACKGROUND: Invasive pulmonary aspergillosis (IPA) is a serious complication occurring in immunocompromised patients, who often show multiple nodular lesions with or without cavitation. Due to high mortality and poor prognosis, the earlier detection and initiation of treatment are needed, while the definitive diagnosis is often difficult to make in clinical settings. Septic pulmonary embolism (SPE) is a complication that occurs in patients with bloodstream infections (e.g., infectious endocarditis). Patients with SPE also present with multiple nodules, nodules with or without cavitation, which are quite similar to the findings of IPA. We herein report an autopsy case that showed multiple nodules due to IPA and infectious endocarditis-related SPE. CASE: A 69-year-old man receiving maintenance hemodialysis due to diabetic nephropathy was admitted with worsening skin rash due to bullous pemphigoid and toxic epidermal necrolysis. He was treated with intravenous methylprednisolone followed by an increased dose of oral prednisolone. On the 6th week of admission, he was diagnosed with infectious endocarditis after the isolation of Corynebacterium in blood samples, with a nodule lesion with cavitation in the right lung. Intravenous vancomycin was initiated. After antibacterial treatment, the nodules in the right lung gradually diminished, whereas a nodule with cavitation in the left lung emerged. The nodule in the left lung showed rapid growth along with elevation of serum ß-D-glucan and galactomannan antigen. Despite starting treatment with antifungal agents, he died from respiratory failure. An autopsy revealed Groccott staining-positive aspergillus in the left lung, but not in the right lung. We found fibrosis with mitral valve vegetation, indicating a recovery from infectious endocarditis. CONCLUSION: Although similar features of nodules with cavitation on CT imaging were shared with SPE and IPA, this case demonstrated that these heterogeneous diseases can occur within the lungs and the distinctly different transitions of CT imaging are helpful for suspecting the presence of multiple pathogeneses.

Long-Term Renal Survival in Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis With Complement C3 Deposition.

INTRODUCTION: Recent studies have revealed the pivotal role of complement activation in the pathogenesis of antineutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN). This study investigated the clinicopathologic and prognostic significance of glomerular C3 deposition in the renal histopathology of patients with ANCA-GN. METHODS: We retrospectively identified 142 patients with ANCA-GN from 6 hospitals in Japan (2004-2020). C3 deposition was defined as C3 staining ≥1+ on a scale of 0 to 2+ using direct immunofluorescence (IF). The primary composite end points included a 30% reduction in estimated glomerular filtration rate (eGFR), end-stage kidney disease (ESKD), and death. We compared clinicopathologic features and long-term outcomes between patients with and without C3 deposition. RESULTS: C3 deposition was observed in 56 of 142 kidney biopsy samples (39.4%). Patients with C3 deposition had a lower serum C3 level (P = 0.002). During a median follow-up of 2.9 (interquartile range: 0.2-5.7) years, 69 events occurred and the cumulative event-free survival rate at 5 years was significantly lower in the C3-positive group than in the C3-negative group (log-rank: P = 0.002). In multivariable analysis, C3 deposition was significantly associated with the composite end points after adjusting for age, sex, baseline eGFR, serum C3 level, treatment, and the percentage of normal glomerulus, cellular crescents, global sclerosis, and interstitial damage (adjusted hazard ratio [HR] = 2.02, 95% confidence interval: 1.20-3.40, P = 0.008). CONCLUSION: This study revealed that ANCA-GN patients with glomerular C3 deposition on IF had worse renal and overall survival rates.

Acute tubulointerstitial nephritis associated with antineutrophil cytoplasmic antibody following cimetidine treatment: a case report.

BACKGROUND: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis usually induces rapidly progressive glomerulonephritis, including pauci-immune necrotizing crescentic glomerulonephritis. Acute tubulointerstitial nephritis (ATIN), which is often drug-induced, is a frequent cause of kidney injury. However, ATIN associated with ANCA without any glomerular lesions has been rarely reported, and drug-induced ATIN associated with ANCA is not well recognized. Here we present a case of an older woman with ATIN associated with myeloperoxidase-ANCA (MPO-ANCA) following cimetidine treatment. CASE PRESENTATION: A 70-year-old woman was admitted to our hospital due to acute kidney injury and mild proteinuria. She had a one-year history of chronic thyroiditis and dyslipidemia, for which she was taking levothyroxine sodium and atorvastatin, respectively. Two weeks before admission she had started cimetidine, methylmethionine sulfonium chloride, and itopride hydrochloride for gastric discomfort persistent since a month. She had experienced fatigue for two weeks and later appetite loss. The patient demonstrated a positive titer for MPO-ANCA (192 IU/mL) and a positive drug-induced lymphocyte stimulation test for cimetidine. She underwent two kidney biopsies that revealed ATIN without any glomerular lesions. Despite discontinuation of cimetidine on admission, renal injury continued with the presence of high MPO-ANCA titer. Oral steroid treatment was closely related with the recovery of her renal function and disappearance of MPO-ANCA. CONCLUSIONS: In this case, ATIN presented as sustained renal insufficiency and high MPO-ANCA titer despite withdrawal of cimetidine. Therefore, we reason that the development of ANCA-associated ATIN was caused by cimetidine. Serologic follow-up with measurement of MPO-ANCA titers and renal biopsy are recommended when the clinical history is inconsistent with the relatively benign course of drug-induced ATIN.

TAFRO Syndrome With Kidney Involvement: A Case Series of Patients With Kidney Biopsies.

TAFRO (thrombocytopenia, anasarca, fever, reticulin myelofibrosis/renal insufficiency, and organomegaly) syndrome is a systemic inflammatory disease sharing some features with Castleman disease and POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes) syndrome in relation to abnormal secretions of interleukin 6 and vascular endothelial growth factor. The kidney is a main target organ of TAFRO syndrome but the kidney histopathology associated with TAFRO syndrome is yet to be completely defined. We report 3 TAFRO syndrome cases with different clinical courses in which kidney biopsies were performed. In all 3 cases, kidney biopsies showed similar glomerular lesions of diffuse global swelling of the endothelium and expansion of subendothelial spaces, consistent with severe glomerular endothelial injury. Case 3 showed an additional finding of focal tubulointerstitial injury characterized by marked plasma cell infiltration, which was absent in the other 2 cases. Clinical symptoms in cases 1 and 2, which had lower disease severity scores of TAFRO syndrome, were effectively treated with the administration of corticosteroids or a combination of corticosteroids and cyclosporine A. Case 3, with a higher disease severity score, had an aggressive clinical course that was refractory to corticosteroids and tocilizumab; the patient ultimately died of multiple organ failure. In all 3 cases, kidney biopsy provided indications for the diagnosis process and clinical management of TAFRO syndrome.

Membranous nephropathy with thrombotic microangiopathy-like lesions successfully treated with tocilizumab in a patient with idiopathic multicentric Castleman disease.

Idiopathic multicentric Castleman disease (iMCD) is a systemic lymphoproliferative disease involving multiple organs, including the kidneys. Membranous nephropathy (MN) has been rarely reported as a complication of iMCD. We herein report the case of a 48-year-old man with a 9-year history of iMCD that was complicated by treatment-resistant nephrotic syndrome due to MN. The first renal biopsy performed at the age of 45 years showed diffuse and global MN with a mild glomerular endothelial injury. He was treated with combined therapy of corticosteroids, immunosuppressants, and tocilizumab, an anti-interleukin-6 (IL-6) receptor monoclonal antibody, which was administered every 2-3 weeks. However, nephrotic syndrome persisted, and renal impairment slowly worsened. Serial biopsy performed at 3 years after the first biopsy confirmed advanced lesions of both MN-related and glomerular endothelial injuries. Modification of the therapeutic strategy to weekly administration of tocilizumab gradually led to the remission of proteinuria, allowing the termination of corticosteroids. Thus, the present case suggests a close link between excessive IL-6 actions and the development of glomerular lesions in iMCD. Successful treatment by strict inhibition of IL-6 actions, in this case, may provide a clue for deciding the therapeutic strategy for severe renal complications associated with iMCD.

Renal Damage in Recurrent Atypical Hemolytic Uremic Syndrome Associated with C3 p.Ile1157Thr Gene Mutation.

Patients with atypical hemolytic uremic syndrome (aHUS) associated with a C3 p.Ile1157Thr mutation show a relatively high renal survival and low mortality rates, but renal histopathological findings after recurrence have been rarely reported. A 30-year-old man with a C3 p.Ile1157Thr mutation experienced a third recurrence of thrombotic microangiopathies with neurological and gastrointestinal disorders. A renal biopsy performed during the recovery phase of acute kidney injury revealed collapsed glomeruli and arteriolar vacuolization. Approximately 10% of glomeruli were globally sclerotic, despite the absence of arterio-/arteriolo-sclerosis. These findings suggest substantial progression of irreversible injuries in multiple organs, including kidneys, which occurs in aHUS patients with repeated thrombotic microangiopathies.

Impact of the number of steroid pulses in tonsillectomy combined with steroid pulse therapy: a nationwide retrospective study in Japan.

BACKGROUND: Steroid pulse therapy with tonsillectomy is known as a major treatment for IgA nephropathy (IgAN). However, its protocol was different among institutions and the effects of varying the number of steroid pulses remain unclear. METHODS: From a total of 1,174 IgAN patients in a multicenter retrospective cohort analysis in Japan, 195 patients were treated by tonsillectomy combined with corticosteroid. They were divided into four groups based on the number of administered steroid pulses from 0 to three (TSP0-3), and remission of urinary abnormalities and renal survival until 1.5-fold increase in serum creatinine level from baseline were analyzed among the four groups and between TSP1 and TSP3. RESULTS: Among the four groups, renal function was relatively good when the estimated glomerular filtration rate was approximately 80-90 mL/min/1.73m2 and proteinuria was relatively mild (< 1.0 g/gCre). The ratio of patients who developed renal dysfunction was < 5% in all groups, and the cumulative renal survival rate by Kaplan-Meier analysis was similar among groups (log-rank test, p = 0.37), despite varying clinical backgrounds and treatments. After adjustment of the background variables between TSP1 and TSP3, the remission rates of urinary abnormalities were similar and the renal survival rate also remained similar (66.8 vs. 85.4%, p = 0.45). CONCLUSIONS: In patients with mild proteinuria and good renal function, the number of steroid pulses did not affect the renal outcome in steroid pulse therapy with tonsillectomy. The adaptation and protocols, such as the number of steroid pulses, should be determined for each IgAN patient's background.