Long-term outcome of adult-onset minimal-change nephropathy

Management of adult patients with podocytopathies: an update from the ERA Immunonephrology Working Group

The histopathological lesions, minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are entities without immune complex deposits which can cause podocyte injury, thus are frequently grouped under the umbrella of podocytopathies. Whether MCD and FSGS may represent a spectrum of the same disease remains a matter of conjecture. Both frequently require repeated high-dose glucocorticoid therapy with alternative immunosuppressive treatments reserved for relapsing or resistant cases and response rates are variable. There is an unmet need to identify patients who should receive immunosuppressive therapies as opposed to those who would benefit from supportive strategies. Therapeutic trials focusing on MCD are scarce, and the evidence used for the 2021 Kidney Disease: Improving Global Outcomes (KDIGO) guideline for the management of glomerular diseases largely stems from observational and pediatric trials. In FSGS, the differentiation between primary forms and those with underlying genetic variants or secondary forms further complicates trial design. This article provides a perspective of the Immunonephrology Working Group (IWG) of the European Renal Association (ERA) and discusses the KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases focusing on the management of MCD and primary forms of FSGS in the context of recently published evidence, with a special emphasis on the role of rituximab, cyclophosphamide, supportive treatment options and ongoing clinical trials in the field.

The Significance of Hematuria in Podocytopathies

BACKGROUND

Hematuria is frequently present in podocytopathies, but its significance and prognostic value is not well described in these proteinuric kidney diseases. This study describes the prevalence and association between hematuria and kidney-related outcomes in these disorders.

METHODS

Hematuria was assessed at the initial urinalysis in participants with the following podocytopathies, membranous nephropathy, minimal change disease, and focal segmental glomerulosclerosis, in the Nephrotic Syndrome Study Network (NEPTUNE) and Cure Glomerulonephropathy (CureGN) cohorts with >24 months of follow-up. Multivariable Cox proportional hazards models were fit for time to composite outcome (end-stage kidney disease or 40% decline in estimated glomerular filtration rate (eGFR) and eGFR <60 ml/min/1.73 m2) and proteinuria remission (UPCR <0.3 mg/mg).

RESULTS

Among the 1,516 adults and children in the study, 528 (35%) participants had focal segmental glomerulosclerosis, 499 (33%) had minimal change disease, and 489 (32%) had membranous nephropathy. Median (IQR) time from biopsy until the initial study urinalysis was 260 days (49, 750), and 498 (33%) participants were positive for hematuria. Participants with hematuria compared to those without, were older (37 [16, 55] vs 33 years [12, 55]), more likely to have an underlying diagnosis of membranous nephropathy (44% vs 27%), had shorter time since biopsy (139 [27, 477] vs 325 [89, 878] days) and higher UPCR (3.8 [1.4, 8.0] vs 0.9 [0.1, 3.1]g/g). After adjusting for diagnosis, age, sex, UPCR, eGFR, time since biopsy, and study cohort, hematuria was associated with a higher riskof reaching the composite outcome (HR 1.31 [1.04, 1.65], p-value 0.02) and lower rate of reaching proteinuria remission (HR 0.80 [0.65-0.98], p-value 0.03).

CONCLUSIONS

Hematuria is prevalent among participants with the three podocytopathies and is significantly and independently associated with worse kidney-related outcomes, including both progressive loss of kidney function remission of proteinuria.

Outcomes of minimal change disease without nephrotic range proteinuria

Minimal change disease (MCD) is characterized by edema and nephrotic range proteinuria (NS). However, the fate of MCD without nephrotic proteinuria requires elucidation. We retrospectively reviewed 79 adults diagnosed with primary MCD at their initial renal biopsy at a tertiary hospital between May 2003 and June 2017. Clinicopathologic features were compared between patients with and without NS. The frequency of flaring to nephrotic proteinuria and renal outcomes were assessed during follow-up. There were 20 and 59 patients in the Non-NS and NS groups, respectively. The Non-NS group had a lower frequency of acute kidney injury (AKI) during the follow-up period [5.0% vs. 59.3%, p <0.001]. The response rate to steroid treatment was 100% in the Non-NS group and 92.3% in the NS group (p = 1.000). Except for one patient, the Non-NS group was treated with steroids when their proteinuria increased to a nephrotic level. There were no differences in the frequency of the first relapse or the number of relapses among patients with initial remission from nephrotic range proteinuria. At the final visit, the complete remission rate was 73.4%. The estimated glomerular filtration rate during follow-up was significantly better in the NS group than the Non-NS group, given the higher rates of AKI at renal biopsy. The rates of renal events, end-stage renal disease, and mortality did not differ between the groups. Adult MCD patients with nephrotic and non-nephrotic range proteinuria showed similar outcomes. Accordingly, this population must be carefully managed, regardless of the amount of proteinuria at renal biopsy.

[Diagnosis and treatment of Minimal Change Disease in adults-2023]

Minimal change disease is a glomerulopathy that clinically manifests as acute onset nephrotic syndrome. A diagnosis is made by renal biopsy, implying the absence of glomerular lesions on light microscopy but detection of extensive podocyte foot process effacement on electron miscroscopy. Considering the typically excellent response to immunosuppressive measures (especially to glucocorticoids), an autoimmune pathogenesis is assumed. Although general prognosis is overall beneficial, steroid-dependent, steroid-resistant and frequently-relapsing disease courses may complicate the management of these patients and necessitate the use of alternative immunosuppressive treatment strategies. Here, the Austrian Society of Nephrology (ÖGN) provides a consensus on how to best diagnose and manage adult patients with minimal change disease.

Age of Onset and Disease Course in Biopsy-Proven Minimal Change Disease: An Analysis From the Cure Glomerulonephropathy Network

RATIONALE & OBJECTIVE

Adolescent- and adult-onset minimal change disease (MCD) may have a clinical course distinct from childhood-onset disease. We characterized the course of children and adults with MCD in the Cure Glomerulonephropathy Network (CureGN) and assessed predictors of rituximab response.

STUDY DESIGN

Prospective, multicenter, observational study.

STUDY PARTICIPANTS

CureGN participants with proven MCD on biopsy.

EXPOSURE

Age at disease onset, initiation of renin-angiotensin-aldosterone system (RAAS) blockade, and immunosuppression including rituximab during the study period.

OUTCOME

Relapse and remission, change in estimated glomerular filtration rate (eGFR), and kidney failure.

ANALYTICAL APPROACH

Remission and relapse probabilities were estimated using Kaplan-Meier curves and gap time recurrent event models. Linear regression models were used for the outcome of change in eGFR. Cox proportional hazards models were used to estimate the association between rituximab administration and remission.

RESULTS

The study included 304 childhood- (≤12 years old), 49 adolescent- (13-17 years old), and 201 adult- (≥18 years) onset participants with 2.7-3.2 years of follow-up after enrollment. Children had a longer time to biopsy (238 vs 23 and 36 days in adolescent- and adult-onset participants, respectively; P<0.001) and were more likely to have received therapy before biopsy. Children were more likely to be treated with immunosuppression but not RAAS blockade. The rate of relapse was higher in childhood- versus adult-onset participants (HR, 1.69 [95% CI, 1.29-2.21]). The probability of remission was also higher in childhood-onset disease (HR, 1.33 [95%CI, 1.02-1.72]). In all groups eGFR loss was minimal. Children were more likely to remit after rituximab than those with adolescent- or adult-onset disease (adjusted HR, 2.1; P=0.003). Across all groups, glucocorticoid sensitivity was associated with a greater likelihood of achieving complete remission after rituximab (adjusted HR, 2.62; P=0.002).

LIMITATIONS

CureGN was limited to biopsy-proven disease. Comparisons of childhood to nonchildhood cases of MCD may be subject to selection bias, given that childhood cases who undergo a biopsy may be limited to patients who are least responsive to initial therapy.

CONCLUSIONS

Among patients with MCD who underwent kidney biopsy, there were differences in the course (relapse and remission) of childhood-onset compared with adolescent- and adult-onset disease, as well as rituximab response.

PLAIN-LANGUAGE SUMMARY

Minimal change disease is a biopsy diagnosis for nephrotic syndrome. It is diagnosed in childhood, adolescence, or adulthood. Patients and clinicians often have questions about what to expect in the disease course and how to plan therapies. We analyzed a group of patients followed longitudinally as part of the Cure Glomerulonephropathy Network (CureGN) and describe the differences in disease (relapse and remission) based on the age of onset. We also analyzed rituximab response. We found that those with childhood-onset disease had a higher rate of relapse but also have a higher probability of reaching remission when compared with adolescent- or adult-onset disease. Children and all steroid-responsive patients are more likely to achieve remission after rituximab.

Clinico-biochemical Profile of Biopsy-proven Minimal Change Disease in Adults from a Tertiary Care Center in South India

Minimal change disease (MCD) is the most common cause of nephrotic syndrome (NS) in children, and in adults, it contributes to 10%-25% of NS. MCD in adults follows a slightly different course associated with increased incidence of steroid resistance, hematuria, and HTN. This is a prospective-record analysis study aimed to analyze the profile of MCD in adults, response to treatment, and relapse rates. A retrospective observational study was carried out and data were collected retrospectively from all biopsy-proven MCD patients between 2012 and 2018. A total of 86 adults were diagnosed to have biopsy-proven MCD. Of these, 32 were excluded due to insufficient data/lost for follow-up. The IBM SPSS Statistics version 22.0 was used for the statistical analysis. Descriptive analysis includes expression of all the explanatory and outcome variables in terms of frequency and proportions for categorical variables whereas in terms of mean ± standard deviation for continuous variables. Chi-square test was used to compare the age, gender, remission, renal failure and response of different drugs, treatment durations, comorbidity conditions, relapse episodes, and different types of infections based on the degree of proteinuria among study patients. A total of 54 biopsy-proven adult MCD patients were analyzed. The mean age of the patients studied was 36.67 years, with the oldest patient being 76 years. In the study group, 37 (68.5%) patients were male and 14 (31.5%) were female. In the study population, 20 (37%) were hypertensive, 3 (5.6%) were diabetic, and 10 (18.5%) had renal failure at presentation. On treatment, 52 out of 54 patients received steroids, of which 41 (75.9%) were steroid responsive, 6 (11.1%) steroid dependent, and 7 (13%) steroid resistant. The mean time for remission in steroidsensitive patients was 8.8 weeks. Among the steroid-dependent and steroid-resistant patients, 11 patients received calcineurin inhibitors (CNIs), of which 3 were CNI resistant. In the study Group 1 patient received cyclophosphamide and two received rituximab. In the study population, two patients failed to achieve remission and one patient was initiated on hemodialysis and later lost for follow-up. Minimal change NS is a type of NS which is highly responsive to steroids with good prognosis in children. Adult MCD patients require a higher and prolonged course of steroid when compared to children. CNIs and rituximab form a promising second-line drug in patients who are steroid resistant/dependent. However, CNI dependency or relapse after stopping steroids is a concern.

Efficacy of low-dose rituximab in minimal change disease and prevention of relapse

BACKGROUND

Minimal change disease (MCD) is a major cause of nephrotic syndrome (NS) in children and a minority of adults. The higher tendency to relapse put patients at risk for prolonged exposure to steroids and other immunosuppressive agents. B cell depletion with rituximab (RTX) may be beneficial to the treatment and prevention of frequently relapsing MCD. Therefore, this study aimed to verify the therapeutic/preventive effects of low-dose RTX on the relapse in adult with MCD.

METHODS

A total of 33 adult patients were selected for the study, including 22 patients with relapsing MCD in relapse treatment group who were treated with low-dose RTX (200 mg per week × 4 following by 200 mg every 6 months) and 11 patients in relapse prevention group with complete remission (CR) after steroid therapy were treated with RTX (200 mg ×1 every 6 months) for preventing the relapse of MCD.

RESULTS

Of the 22 patients with MCD in relapse treatment group, there were 21 cases (95.45%) of remission [2 (9.09%) partial remission (PR), 19 (86.36%) CR], 1 (4.56%) no remission (NR) and 20 (90.90%) relapse-free. The Median duration of sustained remission was 16.3 months (3, 23.5 months, inter quartile range (IQR)). 11 patients in the relapse prevention group during a follow-up of 12 months (9-31 months) had no relapse. The average dose of prednisone in two groups after RTX treatment was significantly lower than before treatment.

CONCLUSION

The results of this study suggested low-dose RTX can significantly reduce relapse rate and steroid dose in adults with MCD with fewer side effects. Low-dose RTX regimens may be beneficial for the treatment of relapsing MCD in adults and may be the preferred regimen for patients at high risk for the development of adverse events from corticosteroids.

Demographic, clinical and laboratory characteristics of adult-onset minimal change disease in Turkey: Turkish Society of Nephrology-Glomerular Diseases (TSN-GOLD) Working Group

PURPOSE

In our study, diagnostic and demographic characteristics of patients diagnosed with minimal change disease (MCD) by biopsy, clinical and laboratory findings in our country were investigated.

METHODS

Data were obtained from the Turkish Society of Nephrology Glomerular Diseases (TSN-GOLD) Working Group database. Demographic characteristics, indications for biopsy, diagnosis of the glomerular diseases, comorbidities, laboratory and biopsy findings of all patients were recorded. The data presented are cross-sectional and includes application data for the biopsy period.

RESULTS

Of 3875 patients, 233 patients with MCD (median age 35.0 years) were included in the study, which constitutes 6.0% of the total glomerulonephritis database. Renal biopsy was performed in 196 (84.1%) patients due to nephrotic syndrome. Median serum creatinine was 0.7 (0.6-1.0) mg/dl, mean eGFR was 104 ± 33 ml/min/1.73 m² and median proteinuria 6000 mg/day. The number of patients under the age of 40 years was 139 (59.7%) (Group A), and the number of patients aged 40 years and over was 94 (40.3%) (Group B). Compared to Group A, global sclerotic glomeruli (24 vs. 43, p < 0.001) interstitial inflammation (15 vs. 34, p < 0.001), interstitial fibrosis (20 vs. 31, p = 0.001, vascular changes (10 vs. 25, p < 0.001) and tubular atrophy (18 vs. 30, p < 0.001) were found to be significantly higher in Group B. There was no difference in immunofluorescent staining properties between the two groups.

CONCLUSION

Our data are generally compatible with the literature. Chronic histopathological changes were more common in patients aged 40 years and older than younger patients. Studies investigating the effects of these different features on renal survival are needed.

T-cell receptor diversity in minimal change disease in the NEPTUNE study

BACKGROUND

Minimal change disease (MCD) is the major cause of childhood idiopathic nephrotic syndrome, which is characterized by massive proteinuria and debilitating edema. Proteinuria in MCD is typically rapidly reversible with corticosteroid therapy, but relapses are common, and children often have many adverse events from the repeated courses of immunosuppressive therapy. The pathobiology of MCD remains poorly understood. Prior clinical observations suggest that abnormal T-cell function may play a central role in MCD pathogenesis. Based on these observations, we hypothesized that T-cell responses to specific exposures or antigens lead to a clonal expansion of T-cell subsets, a restriction in the T-cell repertoire, and an elaboration of specific circulating factors that trigger disease onset and relapses.

METHODS

To test these hypotheses, we sequenced T-cell receptors in fourteen MCD, four focal segmental glomerulosclerosis (FSGS), and four membranous nephropathy (MN) patients with clinical data and blood samples drawn during active disease and during remission collected by the Nephrotic Syndrome Study Network (NEPTUNE). We calculated several T-cell receptor diversity metrics to assess possible differences between active disease and remission states in paired samples.

RESULTS

Median productive clonality did not differ between MCD active disease (0.0083; range: 0.0042, 0.0397) and remission (0.0088; range: 0.0038, 0.0369). We did not identify dominant clonotypes in MCD active disease, and few clonotypes were shared with FSGS and MN patients.

CONCLUSIONS

While these data do not support an obvious role of the adaptive immune system T-cells in MCD pathogenesis, further study is warranted given the limited sample size. A higher resolution version of the Graphical abstract is available as Supplementary information.

Multiple Venous and Pulmonary Artery Thrombosis as the Presenting Features of Spontaneously Reversible Nephrotic Syndrome after Exposure to SARS-CoV-2 Virus (Pfizer/BioNTech BNT162b2) Vaccination

We report an unusual case of nephrotic syndrome and multiple venous thromboembolism (VTE) four days after BNT162b2 injection. The patient presented with a three-day history of foamy urine and one-day history of right leg swelling. The investigation showed 9.5 g of 24 hr urine protein, hypoalbuminemia (2.6 gm/dL), and hypercholesterolemia (320 mg/dL). The duplex ultrasonography revealed VTE of the right lower extremity veins (common femoral vein, saphenous vein, and popliteal vein). Computed tomography (CT) showed thrombosis of the infrarenal inferior vena cava (IVC) extending to both iliac veins and acute pulmonary embolism. Kidney biopsy was performed. The diagnosis of minimal change disease was made. The patient received anticoagulation without steroid or immunosuppressive medications. The nephrosis was spontaneously resolved in 20 days; thus, it strongly suggested the diagnosis of vaccine-induced minimal change nephropathy. Reports of kidney adverse events and clinical characteristics are further needed in the circumstances of worldwide SARS-CoV-2 vaccine usage.

Mycophenolate mofetil and telmisartan for the treatment of proteinuria secondary to minimal change disease podocytopathy in a dog

A 3-year-old entire female Springer Spaniel, with a previous diagnosis of meningoencephalitis of unknown origin diagnosed 2 years before presentation and treated with long term administration of prednisolone, developed proteinuria. Laboratory findings revealed hypoalbuminemia, hypercholesterolemia, and proteinuria. Further investigations excluded underlying causes. Renal biopsies were performed. The glomeruli and the tubulointerstitial compartment did not show any anomalies on light microscopy and immunofluorescence staining did not reveal abnormalities. Transmission electron microscopy revealed moderate podocyte injury consisting of foot process effacement and microvillus transformation of the cytoplasm. The dog was diagnosed with primary minimal change disease of the podocytes and treated with telmisartan and mycophenolate mofetil. Abnormalities of serum albumin, cholesterol, and proteinuria resolved within 4 weeks. Minimal change disease has been reported in dogs, but this is a case report of proteinuria secondary to minimal change disease successfully treated with mycophenolate mofetil and telmisartan.

Spontaneous remission of idiopathic minimal change disease in a cat

Case summary

A 5-year-old female neutered domestic mediumhair cat presented with acute onset hyporexia, lethargy, ascites, hypoalbuminaemia and ventral subcutaneous oedema. Further investigations revealed a bicavitary effusion, myocardial injury, hypercholesterolaemia and concurrent marked proteinuria. A panel of infectious disease tests yielded negative results. Nephrotic syndrome was suspected and renal biopsies were performed. Histopathology and electron microscopy confirmed a diagnosis of minimal change disease (MCD). The patient was successfully managed with benazepril, clopidogrel and a veterinary prescription renal diet. Follow-up two weeks later documented almost complete resolution of the cardiac abnormalities, absence of clinical signs and marked improvement in clinicopathological findings. The hypoalbuminaemia and proteinuria had resolved two months after presentation. At the time of writing, 13 months post-admission, the cat remained asymptomatic with no evidence of disease relapse.

Relevance and novel information

MCD is rarely described in the veterinary literature, with only four cases reported to date. To our knowledge, this report describes the first case of successfully treated MCD-associated nephrotic syndrome in a cat without the use of glucocorticoid treatment.

Predictors of early remission of proteinuria in adult patients with minimal change disease: a retrospective cohort study

Previous studies reported conflicting results regarding an association between serum albumin concentration and the cumulative incidence of remission of proteinuria in adult patients with minimal change disease (MCD). The present study aimed to clarify the clinical impact of serum albumin concentration and the cumulative incidence of remission and relapse of proteinuria in 108 adult patients with MCD at 40 hospitals in Japan, who were enrolled in a 5-year prospective cohort study of primary nephrotic syndrome, the Japan Nephrotic Syndrome Cohort Study (JNSCS). The association between serum albumin concentration before initiation of immunosuppressive treatment (IST) and the cumulative incidence of remission and relapse were assessed using multivariable-adjusted Cox proportional hazards models. Remission defined as urinary protein < 0.3 g/day (or g/gCr) was observed in 104 (96.3%) patients. Of 97 patients with remission within 6 month of IST, 42 (43.3%) developed relapse defined as ≥ 1.0 g/day (or g/gCr) or dipstick urinary protein of ≥ 2+. Serum albumin concentration was significantly associated with remission (multivariable-adjusted hazard ratio [95% confidence interval] per 1.0 g/dL, 0.57 [0.37, 0.87]), along with eGFR (per 30 mL/min/1.73 m²: 1.43 [1.08, 1.90]), whereas they were not associated with relapse. A multivariable-adjusted model showed that patients with high eGFR level (≥ 60 mL/min/1.73 m²) and low albumin concentration (≤ 1.5 g/dL) achieved significantly early remission, whereas those with low eGFR (< 60 mL/min/1.73 m²) and high albumin concentration (> 1.5 g/dL) showed significantly slow remission. In conclusion, lower serum albumin concentration and higher eGFR were associated with earlier remission in MCD, but not with relapse.

A Prediction Model for Acute Kidney Injury in Adult Patients With Minimal Change Disease

Background

Early prediction of acute kidney injury (AKI) can allow for timely interventions, but there are still few methods that are easy and convenient to apply in predicting AKI, specially targeted at patients with minimal change disease (MCD). Motivated by this, we aimed to develop a predicting model for AKI in patients with MCD within the KDIGO criteria.

Methods

Data on 401 hospitalized adult patients, whose biopsy was diagnosed as MCD from 12/31/2010 to 15/7/2021, were retrospectively collected. Among these data, patients underwent biopsy earlier formed the training set (n = 283), while the remaining patients formed the validation set (n = 118). Independent risk factors associated with AKI were analyzed. From this, the prediction model was developed and nomogram was plotted.

Results

AKI was found in 55 of 283 patients (19%) and 15 of 118 patients (13%) in the training and validation cohorts, respectively. According to the results from lasso regression and logistic regression, it was found that four factors, including mean arterial pressure, serum albumin, uric acid, and lymphocyte counts, were independent of the onset of AKI. Incorporating these factors, the nomogram achieved a reasonably good concordance index of 0.84 (95%CI 0.77–0.90) and 0.75 (95%CI 0.62–0.87) in predicting AKI in the training and validation cohorts, respectively. Decision curve analysis suggested clinical benefit of the prediction models.

Conclusions

Our predictive nomogram provides a feasible approach to identify high risk MCD patients who might develop AKI, which might facilitate the timely treatment.

Time to remission of proteinuria and incidence of relapse in patients with steroid-sensitive minimal change disease and focal segmental glomerulosclerosis: the Japan Nephrotic Syndrome Cohort Study

BACKGROUND

Minimal change disease (MCD) is characterized by a nephrotic syndrome usually steroid-sensitive and a high incidence of relapse of proteinuria. Previous cohort studies have reported conflicting results regarding the association between the time to remission and incidence of relapse.

METHODS

This multicenter prospective cohort study included 102 adult patients with steroid-sensitive MCD or focal segmental glomerulosclerosis from a 5-year cohort study of primary nephrotic syndrome, the Japan Nephrotic Syndrome Cohort Study, who achieved remission of proteinuria within 2 months of immunosuppressive therapy (IST). The association between the time to remission of proteinuria after immunosuppressive therapy and incidence of relapse was assessed using Cox proportional hazards models adjusted for clinically relevant factors.

RESULTS

Remission was observed at 3-7, 8-14, 15-21, 22-28, and 30-56 days after initiation of immunosuppressive therapy in 17 (16.7%), 37 (36.3%), 21 (20.6%), 13 (12.7%), and 14 (13.7%) patients, respectively. During a median observation period of 2.3 years after the end of the 2nd month after initiation of immunosuppressive therapy, 46 (45.1%) patients relapsed. The time to remission was associated with the incidence of relapse in an inverse U-shaped pattern (multivariable-adjusted hazard ratios [95% confidence intervals] of the time to remission of 3-7, 8-14, 15-21, 22-28, 30-56 days: 1.00 [reference], 1.76 [0.56, 5.51], 6.06 [1.85, 19.80], 5.46 [1.44, 20.64], and 2.19 [0.52, 9.30], respectively).

CONCLUSION

The time to remission was identified as a significant predictor of relapse in steroid-sensitive patients.

Minimal Change Disease Is Associated with Mitochondrial Injury and STING Pathway Activation

We hypothesized that minimal change disease (MCD) pathogenesis may be associated with mitochondrial injury, and that the degree of mitochondrial injury at the time of diagnosis may serve as a valuable prognostic marker. We compared urinary mitochondrial DNA (mtDNA) at the time of diagnosis in patients with MCD and age- and sex-matched healthy controls (MHC) (n = 10 each). We analyzed the site and signal intensity of immunohistochemical (IHC) staining of stimulator of interferon genes (STING) using kidney tissues at the time of diagnosis in patients with MCD. Patients with MCD were divided into high (n = 6) and low-intensity (n = 14) subgroups according to the signal intensity. Urinary mtDNA levels were elevated in the MCD groups more than in the MHC group (p < 0.001). Time-averaged proteinuria and frequency of relapses during the follow-up period were higher in the high-intensity than in the low-intensity subgroup (1.18 ± 0.54 vs. 0.57 ± 0.45 g/day, p = 0.022; and 0.72 ± 0.60 vs. 0.09 ± 0.22 episodes/year, p = 0.022, respectively). Mitochondrial injury may be associated with MCD pathogenesis, and the signal intensity of STING IHC staining at the time of diagnosis could be used as a valuable prognostic marker in MCD.

Urine Single-Cell RNA Sequencing in Focal Segmental Glomerulosclerosis Reveals Inflammatory Signatures

Introduction

Individuals with focal segmental glomerular sclerosis (FSGS) typically undergo kidney biopsy only once, which limits the ability to characterize kidney cell gene expression over time.

Methods

We used single-cell RNA sequencing (scRNA-seq) to explore disease-related molecular signatures in urine cells from subjects with FSGS. We collected 17 urine samples from 12 FSGS subjects and captured these as 23 urine cell samples. The inflammatory signatures from renal epithelial and immune cells were evaluated in bulk gene expression data sets of FSGS and minimal change disease (MCD) (The Nephrotic Syndrome Study Network [NEPTUNE] study) and an immune single-cell data set from lupus nephritis (Accelerating Medicines Partnership).

Results

We identified immune cells, predominantly monocytes, and renal epithelial cells in the urine. Further analysis revealed 2 monocyte subtypes consistent with M1 and M2 monocytes. Shed podocytes in the urine had high expression of marker genes for epithelial-to-mesenchymal transition (EMT). We selected the 16 most highly expressed genes from urine immune cells and 10 most highly expressed EMT genes from urine podocytes as immune signatures and EMT signatures, respectively. Using kidney biopsy transcriptomic data from NEPTUNE, we found that urine cell immune signature and EMT signature genes were more highly expressed in FSGS biopsies compared with MCD biopsies.

Conclusion

The identification of monocyte subsets and podocyte expression signatures in the urine samples of subjects with FSGS suggests that urine cell profiling might serve as a diagnostic and prognostic tool in nephrotic syndrome. Furthermore, this approach may aid in the development of novel biomarkers and identifying personalized therapies targeting particular molecular pathways in immune cells and podocytes.

Association of initial prednisolone dose with remission, relapse, and infectious complications in adult-onset minimal change disease

BACKGROUND

A dose of 0.5-1 mg/kg/day of prednisolone (PSL) is administered for the initial treatment of minimal change disease (MCD). However, little is known about the optimal PSL dose for the initial treatment of MCD.

METHODS

We conducted a retrospective multicenter cohort study of treatment-naive adult patients with MCD diagnosed by renal biopsy from 1981 to 2015 in whom PSL monotherapy was performed as the initial treatment. The exposure of interest was an initial median PSL dose of < 0.63 mg/kg/day (Group L) compared to ≥ 0.63 mg/kg/day (Group H). Cumulative remission and relapse after remission were compared between these groups using Cox regression adjusted for baseline characteristics.

RESULTS

Ninety-one patients met the inclusion criteria. During a median follow-up of 2.98 years, 87 (95.6%) patients achieved complete remission, and 47.1% relapsed after remission. There was no significant difference in the remission rate between the groups at 4 weeks of follow-up (66.7 vs. 82.6%). The median time to remission in Group L was comparable to that in Group H (17.0 vs. 14.0 days). A multivariable Cox hazard model revealed that the initial PSL dose was not a significant predictor of remission. The cumulative steroid doses at 6 months, 1 year, and 2 years after treatment initiation were significantly lower in Group L than in Group H.

CONCLUSION

The initial PSL dose was not associated with time to remission, remission rate, time to relapse, or relapse rate. Therefore, a low initial steroid dose may be sufficient to achieve remission.

Steroid Minimization in Adults with Minimal Change Disease

Background

Minimal change disease (MCD) causes approximately 10% of nephrotic syndrome in adults. While glucocorticoids (GCs) effectively induce remission in MCD, the disease has a high relapse rate (50-75%), and repeated exposure to GCs is often required. The adverse effects of GCs are well recognized and commonly encountered with the high doses and recurrent courses used in MCD.

Summary

In this review, we will discuss the standard therapy of MCD in adults and then describe new therapeutic options in induction therapy and treatment of relapses in MCD, minimizing the exposure to GCs.

Key Messages

Steroid minimization strategies may decrease adverse effects in the treatment of MCD.

Metabolomics analysis of serum in pediatric nephrotic syndrome based on targeted and non-targeted platforms

BACKGROUND AND AIMS

Nephrotic syndrome (NS) is a common pediatric urinary system disease. The aim in this work was to investigate the changes in pediatric NS-related metabolites through serum metabolomics, and explore the new potential metabolites and differential metabolic pathways.

METHODS

Serum samples from 40 pediatric patients with nephrotic syndrome and 40 healthy controls were collected. The targeted and non-targeted metabolomics analyses were performed to determine the metabolic changes in pediatric NS. Based on multivariate statistical analysis and the regression model, the serum potential metabolites were screened and different metabolic pathways were explored.

RESULTS

39 differential metabolites in pediatric NS were obtained based on the metabolomics analysis. 12 differential metabolites (serine, C18: 2 (EFA), C18: 2 (FFA), Isonuatigenin 3- [rhamnosyl- (1- > 2) -glucoside], C18: 4 (EFA), C18: 4 (FFA), caprylic acid, citric acid, methylmalonic acid, caproic acid, canavalioside and uroporphyrin were identified to establish the diagnostic model for pediatric NS. Five metabolic pathways including TCA cycle, amino acid metabolism, bile acid biosynthesis, linoleate metabolism and glyoxylate and dicarboxylate metabolism were the key differential metabolic pathways.

CONCLUSION

These data elucidated the metabolic alterations associated with pediatric NS and suggested a new diagnosis model for monitoring pediatric NS. The current study provides the useful information to bridge the gaps in our understanding of the metabolic alterations associated with pediatric NS and might facilitate the characterization of pediatric NS patients by performing serum metabolomics.

Spontaneous remission of minimal change nephrotic syndrome in an elderly man

Minimal change nephrotic syndrome (MCNS) cases achieving spontaneous remission without external factors are rarely reported. We report a case of MCNS that achieved spontaneous remission without external factors that triggered its onset. An 82-year-old male patient was admitted to the hospital for close examination of nephrotic syndrome. Renal biopsy was performed and MCNS was diagnosed. Owing to the patient's age and history of foot and microvascular arteriovenous thrombosis, we did not start immunosuppressive drugs, including steroids, and opted for conservative management. After conservative treatment, proteinuria gradually decreased, and the patient achieved complete remission. Given that the patient had a history of urinary protein and thrombosis, recurrence of MCNS was considered again this time. In addition, the involvement of external factors that trigger the onset of MCNS was not found. In conclusion, in elderly-onset MCNS, clinicians generally hesitate to initiate treatment with an immunosuppressive drug, containing steroids, because of its many complications. Thus, our data provide valuable insight into MCNS.

Adult-onset minimal change disease: the significance of histological chronic changes for clinical presentation and outcome

INTRODUCTION

Data on pathologic features with prognostic utility in adults with minimal change disease (MCD) are limited. We assessed the relationship between histologic chronic changes and clinical presentation and outcomes.

METHODS

The consecutive records of 79 patients with MCD and minimum of 6 months follow-up were retrospectively reviewed. Kidney survival was the primary endpoint (doubling serum creatinine or dialysis initiation). Secondary endpoints were time to remission and relapse. Total chronicity score was the sum of glomerulosclerosis (0-3), interstitial fibrosis (0-3), tubular atrophy (0-3), and arteriolosclerosis (0/1).

RESULTS

The median renal chronicity score was 1; 77% had minimal (0-1), 18% mild (2-4), and 5% moderate (5-7) chronicity. Fifty percent had a null score; they were younger, had higher eGFR, similar proteinuria, better renal survival, and lower mortality. Mean kidney survival time was 5.7 (95% CI 5.2-6.2) years; 89% reached a form of remission at a median of 8 weeks; 31% relapsed at a mean of 26 months. Chronic changes severity predicted both relapses and kidney survival, each one-point increase in score raised with 27% the risk of relapse and with 31% the risk of dialysis initiation. Acute kidney injury (AKI) was present in 42% of the patients; they had more often mesangial proliferation, interstitial inflammation, tubular atrophy, arteriosclerosis, podocyte villous hypertrophy, and higher chronicity score.

CONCLUSION

Standardized grading of chronicity was a predictor of kidney survival and disease relapse and was related to AKI. Older patients with severe nephrotic syndrome and with increased chronicity score could represent a high-risk category.

Comparison of treatment options in adults with frequently relapsing or steroid-dependent minimal change disease

Background

Studies comparing all treatment options for frequently-relapsing/steroid-dependent (FR/SD) minimal change disease (MCD) in adults are lacking.

Methods

Medical records of 76 adults with FR/SD MCD who were treated with corticosteroids as the first-line therapy were reviewed. Treatment options were compared for the time to relapse, change of therapy and progression (relapse on full-dose treatment).

Results

Second-line treatments included rituximab (RTX; n = 13), mycophenolate mofetil (MMF; n = 12), calcineurin inhibitors (CNI; n = 26) and cyclophosphamide (CTX; n = 16). During the second-line treatments, 48 (71.6%) patients relapsed at median 17 (range 2–100)  months. The majority of relapses occurred during dose tapering or off drug. Twenty of 65 (30.8%) changed therapy after the first relapse. The median time to relapse after the second line was 66 versus 28 months in RTX versus non-RTX groups (P = 0.170). The median time to change of treatment was 66 and 44 months, respectively (P = 0.060). Last-line treatment options included RTX (n = 8), MMF (n = 4), CNI (n = 3) and CTX (n = 2). Seven (41.2%) patients had a relapse during the last-line treatment at median 39 (range 5–112)  months. The median time to relapse was 48 versus 34 months in the RTX versus non-RTX groups (P = 0.727). One patient in the RTX group died presumably of heart failure. No major adverse event was observed. During the median follow-up of 81 (range 9–355)  months, no patients developed end-stage renal disease.

Conclusions

Relapse is frequent in MCD in adults. Patients treated with RTX may be less likely to require a change of therapy and more likely to come off immunosuppressive drugs.

Podocytopathies

Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.

Nephrotic syndrome due to minimal-change disease superimposed on anti-glomerular basement membrane antibody positive glomerulonephritis; a case report

Background

The prognosis for renal function in anti-GBM glomerulonephritis (anti-GBM GN) is extremely poor, and when renal impairment progresses severely, it is difficult to expect improvement. In addition, it is also known that once the disease activity can be controlled by aggressive treatment, its recurrence is rare. We experienced an anti-GBM GN that improved from severe renal dysfunction and relapsed. A possible cause was the superimpose of nephrotic syndrome due to minimal change disease (MCD).

Case presentation

A 30-year-old man was admitted to our hospital because of general malaise, fever, oliguria and renal dysfunction. The patient’s laboratory data showed serum creatinine as high as 6.6 mg/dl, and severe inflammation (C-reactive protein 20.6 mg/dl). Anti-glomerular basement membrane antibody (anti-GBM Ab) was detected in his serum, which led to the diagnosis of anti-GBM GN. Treatment was initiated with high-dose glucocorticoid (GC) and plasma exchange therapy (PE), and the patient’s renal function and oliguria improved rapidly and he was discharged 40 days after admission. Renal biopsy findings showed cellular crescents associated with linear IgG depositions along the glomerular tufts compatible with anti-GBM GN, but only about one-third of the glomeruli was involved, suggesting that it still remains an early stage of the disease. However, 2 months after discharge, he had a relapse and was readmitted due to severe proteinuria with positive anti-GBM Ab. On the second admission, after high-dose GC and PE combined with intravenous cyclophosphamide, and remission was achieved. Despite the relatively minor renal biopsy findings, the patient showed rapid renal dysfunction and relatively rapid improvement with our treatment. Electron microscopy of the renal biopsy tissue showed significant foot process effacement on podocytes in the apparently normal glomeruli, without electron dense deposits.

Conclusion

On the basis of clinical course and renal pathology, it is suggested that the present case was a rare complication of an early stage of anti-GBM GN and minimal change nephrotic syndrome. Although the simultaneous development of anti-GBM GN and MCD with anti-GBM antibody is unclear, it might have been precipitated by influenza infection or some unknown factor.

Randomized, Controlled Trial of Tacrolimus and Prednisolone Monotherapy for Adults with De Novo Minimal Change Disease: A Multicenter, Randomized, Controlled Trial

BACKGROUND AND OBJECTIVES

Minimal change disease is an important cause of nephrotic syndrome in adults. Corticosteroids are first-line therapy for minimal change disease, but a prolonged course of treatment is often required and relapse rates are high. Patients with minimal change disease are therefore often exposed to high cumulative corticosteroid doses and are at risk of associated adverse effects. This study investigated whether tacrolimus monotherapy without corticosteroids would be effective for the treatment of de novo minimal change disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a multicenter, prospective, open-label, randomized, controlled trial involving six nephrology units across the United Kingdom. Adult patients with first presentation of minimal change disease and nephrotic syndrome were randomized to treatment with either oral tacrolimus at 0.05 mg/kg twice daily, or prednisolone at 1 mg/kg daily up to 60 mg daily. The primary outcome was complete remission of nephrotic syndrome after 8 weeks of therapy. Secondary outcomes included remission of nephrotic syndrome at 16 and 26 weeks, rates of relapse of nephrotic syndrome, and changes from baseline kidney function.

RESULTS

There were no significant differences between the tacrolimus and prednisolone treatment cohorts in the proportion of patients in complete remission at 8 weeks (21 out of 25 [84%] for prednisolone and 17 out of 25 [68%] for tacrolimus cohorts; P=0.32; difference in remission rates was 16%; 95% confidence interval [95% CI], -11% to 40%), 16 weeks (23 out of 25 [92%] for prednisolone and 19 out of 25 [76%] for tacrolimus cohorts; P=0.25; difference in remission rates was 16%; 95% CI, -8% to 38%), or 26 weeks (23 out of 25 [92%] for prednisolone and 22 out of 25 [88%] for tacrolimus cohorts; P=0.99; difference in remission rates was 4%; 95% CI, -17% to 25%). There was no significant difference in relapse rates (17 out of 23 [74%] for prednisolone and 16 out of 22 [73%] for tacrolimus cohorts) for patients in each group who achieved complete remission (P=0.99) or in the time from complete remission to relapse.

CONCLUSIONS

Tacrolimus monotherapy can be effective alternative treatment for patients wishing to avoid steroid therapy for minimal change disease.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_01_16_CJN06180519.mp3.

Idiopathic Nephrotic Syndrome: Characteristics and Identification of Prognostic Factors

There are various histopathological forms of idiopathic nephrotic syndrome, including minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). Whereas some relapse predictor factors have been identified in renal transplantation, the clinical future of idiopathic nephrotic syndrome in the native kidney remains uncertain. We designed a multicentric retrospective descriptive cohort study including all patients aged 15 years and over whose renal biopsy confirmed MCD or FSGS between January 2007 and December 2014. We studied 165 patients with idiopathic nephrotic syndrome; 97 with MCD and 68 with FSGS. In the MCD cohort, 91.7% of patients were treated with corticosteroids for a median total duration of 13 months. During 45 months of follow-up, 92.8% of patients achieved remission and 45.5% experienced relapse. In this cohort, 5% of patients experienced terminal kidney disease. With respect to FSGS patients, 51.5% were treated with corticosteroids for a median total duration of 15 months. During 66 months of follow-up, 73.5% of patients achieved remission and 20% experienced relapse. In this cohort, 26.5% of patients experienced terminal kidney disease. No statistical association was observed between clinical and biological initial presentation and relapse occurrence. This study describes the characteristics of a cohort of patients with the nephrotic idiopathic syndromes of MCD and FSGS from the time of renal biopsy and throughout follow-up.

Adult minimal-change disease: observational data from a UK centre on patient characteristics, therapies, and outcomes

Background

Minimal change disease (MCD) is a common cause of the nephrotic syndrome in adults with limited evidence on its treatment and prognosis. We examined the presenting characteristics, treatments, and outcomes of adult patients with MCD in our centre.

Methods

This was an observational cohort study using retrospectively-collected data. All patients who had a renal biopsy reported as MCD between 1996 and 2012 were included, and data were collected at baseline and during follow-up. Statistical analysis included Cox-regression analysis to examine which factors were associated with risk of relapse.

Results

Seventy-eight patients were included, and had a median age of 36 years, and were 60% male and 73% white. Median follow-up time was 72 months. 37% were in AKI at presentation, which was significantly associated with a lower serum albumin and older age. Although 10% were steroid-resistant, 98% achieved remission at a median time of 5 weeks. 61% relapsed, at a median time of 11 months, and patients had a median number of 2 relapses during follow-up. A higher eGFR was associated with an increased risk of relapse (hazard ratio 1.18 [1.03–1.36] per 10 mL/min increase in eGFR), and females were significantly more likely than males to have an early relapse. Nearly half of the cohort required an additional immunosuppressive agent on top of glucocorticoids, the most commonly used being calcineurin inhibitors. Five patients subsequently developed FSGS: these patients had a lower baseline creatinine, a higher serum albumin, a longer time to remission, and were more likely to be steroid-resistant. Follow-up renal function was generally preserved, but follow-up creatinine was higher in those who had presented with AKI, and in those who had been commenced on a RAS inhibitor after biopsy. Infection requiring admission, diabetes mellitus and venous thromboembolism developed in 14%, 12%, and 12% of patients respectively.

Conclusions

Nearly all adults with MCD achieve remission, but relapses and disease- and therapy-related complications are common. In our cohort, eGFR and gender were associated with risk of relapse, and these previously undescribed associations could be explored further in future work.

Does cyclophosphamide still play a role in glomerular diseases?

Cyclophosphamide is a prodrug that is converted to inactive carboxy-cyclophosphamide, acrolein and phosphoramide mustard, an agent that adds alkyl groups to oxygen and nitrogen atoms of guanine, one of the four nitrogen bases that form the DNA nucleotides, causing DNA cross-links and introducing DNA breaks. These cytotoxic and mutagenic effects mainly occur in proliferating cells. Repair mechanisms may prevent DNA damage in quiescent cells, but they may be insufficient to contrast the side effects of cyclophosphamide if high doses of the drug are used. Most adverse events are dose- and age-dependent. Phosphoramide mustard can cause bone marrow toxicity, gonadal toxicity, and may favor the development of leukemia, bladder cancer and other types of malignancy. Acrolein can produce hemorrhagic cystitis and even bladder fibrosis when given for prolonged periods. A number of precautional measures should be taken to prevent these untoward events. In particular, long-term administration and high doses of cyclophosphamide should be avoided whenever possible. Today the indications to cyclophosphamide in glomerular diseases are more restricted than in the past, but the drug is still used as a steroid-sparing agent in steroid-sensitive minimal change disease and focal segmental glomerulosclerosis. In membranous nephropathy, cyclophosphamide, alternated or associated with corticosteroids, proved to be beneficial in obtaining remission of nephrotic syndrome and preserving renal function. Cyclophosphamide is considered as a first-line treatment for rapidly progressive glomerulonephritis and the hectic phases of lupus nephritis. In conclusion, cyclophosphamide is a cheap drug that may be useful in a number of glomerular diseases but it may lead to severe side effects. A close monitoring of blood count and clinical conditions, as well as low cumulative doses of cyclophosphamide are strongly recommended when using the drug in patients with renal diseases.

Spontaneous remission of adult-onset minimal change nephrotic syndrome associated with influenza B infection: a case report

Background

While the majority of adult-onset minimal change nephrotic syndrome (MCNS) is a primary or an idiopathic form of disease, it can also occur as a secondary form. Reports on the spontaneous remission of MCNS are rare since the condition is typically treated with corticosteroids. We herein describe the spontaneous remission of adult-onset MCNS in a patient who developed nephrotic syndrome after type B influenza infection.

Case presentation

A 50-year-old woman experienced fever, cough, malaise, and low back pain, which had persisted for 6 days before she presented to our hospital, and edema of the face and limbs, which had persisted for 5 days before her presentation. She was diagnosed with type B influenza infection and later exhibited an exacerbation of facial edema, decreased urine output, and a high level of proteinuria. She was referred to our department after the diagnosis of nephrotic syndrome. On admission, her proteinuria level was 20.88 g/gCr and her selectivity index value was 0.13. The examination of a kidney biopsy specimen obtained on the fourth day of hospitalization under a light microscope revealed minor abnormalities. An immunofluorescence showed only nonspecific granular IgM deposits in the mesangium. Electron microscopy showed extensive foot process effacement without any immune complex deposits. Based on these findings, the patient was diagnosed with MCNS. After admission, the proteinuria decreased to 0.06 g/gCr with rest and sodium restriction (6 g/day) alone; a complete remission from nephrotic syndrome was observed at approximately 2 weeks after the onset of symptoms. There have been no signs of recurrence of nephrotic syndrome in the one years since.

Conclusion

We experienced a rare case in which spontaneous remission of MCNS occurred within a short period of 2 weeks after influenza B infection. When patients present with nephrotic syndrome after an infection, it is necessary to consider MCNS in the differential diagnosis, which also includes post-infectious glomerulonephritis and the acute exacerbation of IgA nephropathy.

Acute kidney injury complicating nephrotic syndrome of minimal change disease

Minimal change disease accounts for 70% to 90% of cases of nephrotic syndrome in children. It also causes nephrotic syndrome in adults, including patients older than age 60. Renal function is altered moderately in approximately 20% to 30% of patients because foot-process fusion impairs filtration of water and solutes. The glomerular filtration rate is reduced by approximately 20% to 30% and returns to baseline with remission of proteinuria. Over the past 50 years, a number of publications have reported cases of acute kidney injury occurring in approximately one-fifth to one-third of adult cases in the absence of prior or concomitant renal disease. Clinical attributes point to a male predominance, age >50, massive proteinuria, severe hypoalbuminemia, a background of hypertension and vascular lesions on kidney biopsy, along with ischemic tubular necrosis. Acute kidney injury may require dialysis for weeks or months until remission of proteinuria allows resolution of oliguria. In some cases, renal function does not recover. An effect of endothelin-1-induced vasoconstriction at the onset of proteinuria has been proposed to explain tubular cell ischemic necrosis. The main factors causing acute kidney injury in patients with minimal change disease are diuretic-induced hypovolemia and nephrotoxic agents. Acute kidney injury is uncommon in children in the absence of intercurrent complications. Infection, nephrotoxic medication, and steroid resistance represent the main risk factors. In all patients, the goal of supportive therapy is essentially to buy time until glucocorticoids obtain remission of proteinuria, which allows resolution of renal failure.

Treatment patterns and steroid dose for adult minimal change disease relapses: A retrospective cohort study

Background

In patients with adult minimal change disease (MCD), proteinuria relapse is a problem to solve. However, the optimal relapse treatment regimen remains unclear regarding steroid dose. We described the treatment pattern of adult MCD patients and evaluated the appropriate steroid dose for relapse treatment.

Methods

This retrospective multicenter cohort study included 192 patients with adult biopsy-proven MCD from 14 hospitals in Japan. The prescription pattern of immunosuppressive drugs in relapse was reviewed. To assess the association between steroid dose used for relapse and subsequent outcomes, data of patients with tapered prednisolone (PSL) dosage to <10 mg/day before the first relapse in whom the dose was subsequently increased to ≥10 mg/day were extracted and assigned to the High-PSL or Low-PSL groups, based on the median dose of 20 mg/day. Multivariate Cox proportional hazard model and propensity score analysis with multiple imputations were conducted to compare their clinical course.

Results

During a median observation period of 37.6 months, 186/192 (96.9%) patients achieved complete remission (CR) and 100 (52.1%) relapsed. The median urinary protein level at the first relapse was 3.12 g/gCr or g/day. The proportion of non-steroidal immunosuppressant use increased with relapses; cyclosporine was the most common. No significant differences were found in the second relapse, frequent relapses, or adverse events between High-PSL (n = 34) and Low-PSL (n = 36) groups. A multivariate Cox proportional hazard model revealed that the hazard ratios adjusted with propensity score for the second relapse were 0.94 (High-PSL vs. Low-PSL; 95% confidence interval, 0.42–2.10; P = 0.88) and 0.82 (PSL dose per 10 mg/day; 95% confidence interval, 0.58–1.16; P = 0.25).

Conclusions

Among patients in CR with PSL dose <10 mg/day, higher steroid dose (PSL >20 mg/day) was not associated with favorable outcomes after the first relapse as compared to lower dose (10–20 mg/day).

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.

A Case of Steroid Resistant Minimal Change Disease Associated with Portal Vein Thrombosis Treated by Combined Immunosuppressive Agents

Minimal change disease (MCD) is a common cause of nephrotic syndrome and relatively well responds with steroid treatment. However, nearly half of patients with MCD experience recurrence of nephrotic syndrome. Thromboembolic events including renal vein thrombosis may occur in patients with MCD, but portal vein thrombosis rarely occurs. We experienced a case of frequent relapse/steroid dependent MCD with nephrotic syndrome progressed to steroid resistance associated with portal vein thrombosis. This patient showed complete remission of MCD and resolution of portal vein thrombosis after treatment with corticosteroid, cyclosporine, mycophenolate mofetil, and anticoagulant.

Recent Treatment Advances and New Trials in Adult Nephrotic Syndrome

The etiology of nephrotic syndrome is complex and ranges from primary glomerulonephritis to secondary forms. Patients with nephrotic syndrome often need immunosuppressive treatment with its side effects and may progress to end stage renal disease. This review focuses on recent advances in the treatment of primary causes of nephrotic syndrome (idiopathic membranous nephropathy (iMN), minimal change disease (MCD), and focal segmental glomerulosclerosis (FSGS)) since the publication of the KDIGO guidelines in 2012. Current treatment recommendations are mostly based on randomized controlled trials (RCTs) in children, small RCTs, or case series in adults. Recently, only a few new RCTs have been published, such as the Gemritux trial evaluating rituximab treatment versus supportive antiproteinuric and antihypertensive therapy in iMN. Many RCTs are ongoing for iMN, MCD, and FSGS that will provide further information on the effectiveness of different treatment options for the causative disease. In addition to reviewing recent clinical studies, we provide insight into potential new targets for the treatment of nephrotic syndrome from recent basic science publications.

The Evolving Role of Rituximab in Adult Minimal Change Glomerulopathy

BACKGROUND

Minimal-change glomerulopathy is defined histologically by the presence of normal glomeruli on light microscopy and diffuse podocyte effacement on electron microscopy. Although effective in children, corticosteroid treatment in adults is more variable and time to response can be prolonged. Data to support rituximab use in adults with corticosteroid-dependent or resistant minimal-change glomerulopathy are limited. Here, we describe the clinical course of adults with corticosteroid-dependent or -resistant minimal-change glomerulopathy who received rituximab.

METHODS

Demographic and clinical data were collected and analyzed from all adult patients with native kidney, biopsy-proven, minimal-change glomerulopathy who were administered rituximab between 2009 and 2014 and cared for at the UNC Kidney Center.

RESULTS

Ten patients with corticosteroid-resistant (n = 5) or corticosteroid-dependent (n = 5) idiopathic minimal-change glomerulopathy were treated with rituximab between 2009 and 2014. Rituximab treatment induced remission in all 10 patients with a median time to remission of 2 months. The median time from rituximab to corticosteroid discontinuation was 3.5 months. The median remission time was 29 months and follow-up time was 39.5 months. No serious adverse events attributable to rituximab were observed.

CONCLUSION

Rituximab induced remission in all patients with corticosteroid-dependent or -resistant minimal-change glomerulopathy, and may hold great therapeutic potential with good efficacy and minimal toxicity. Mounting evidence implies that a well-conducted randomized controlled clinical trial using rituximab in adults with minimal-change glomerulopathy in both corticosteroid-resistant and corticosteroid-dependent patients is warranted.

Influence of acute kidney injury on the time to complete remission in adult minimal change nephrotic syndrome: a single-centre study

AIM

Acute kidney injury (AKI) is a common complication of minimal change nephrotic syndrome (MCNS), particularly in adults. We evaluated the prevalence of AKI at the onset of adult MCNS and analyzed the influence of AKI on the duration of achieving complete remission (CR).

METHODS

A retrospective, single-centre, dynamic cohort study was conducted with biopsy-proven, first-onset, adult MCNS patients treated with corticosteroids. Fifty-three consecutive patients diagnosed with MCNS from January 2000 to April 2014 were enrolled. Age, gender, daily urinary protein excretion, and serum creatinine levels were measured. To evaluate AKI during induction, we used the Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guidelines for AKI and judged AKI stage according to the fluctuations in serum creatinine levels during the first 4 weeks of starting corticosteroid therapy.

RESULTS

Twenty patients (37.7%) met the AKI criteria and all 53 patients achieved CR within 1 year. Kaplan-Meier analysis showed that the median time to CR was significantly longer in patients with AKI than in patients without AKI. Cox proportional hazard analysis showed that the hazard ratio (HR) associated with the presence of AKI for achieving CR within 4 weeks was 0.36 after adjustment for age, gender, serum albumin, daily urinary protein excretion, hypertension, administration of 25% albumin, and methylprednisolone pulse therapy. A graded association was also observed between AKI stage and HR for achieving CR.

CONCLUSIONS

The prevalence of AKI is high in adult patients with MCNS during induction therapy. AKI is an independent factor that delays the time to CR.

Minimal Change Disease

Minimal change disease (MCD) is a major cause of idiopathic nephrotic syndrome (NS), characterized by intense proteinuria leading to edema and intravascular volume depletion. In adults, it accounts for approximately 15% of patients with idiopathic NS, reaching a much higher percentage at younger ages, up to 70%-90% in children >1 year of age. In the pediatric setting, a renal biopsy is usually not performed if presentation is typical and the patient responds to therapy with oral prednisone at conventional doses. Therefore, in this setting steroid-sensitive NS can be considered synonymous with MCD. The pathologic hallmark of disease is absence of visible alterations by light microscopy and effacement of foot processes by electron microscopy. Although the cause is unknown and it is likely that different subgroups of disease recognize a different pathogenesis, immunologic dysregulation and modifications of the podocyte are thought to synergize in altering the integrity of the glomerular basement membrane and therefore determining proteinuria. The mainstay of therapy is prednisone, but steroid-sensitive forms frequently relapse and this leads to a percentage of patients requiring second-line steroid-sparing immunosuppression. The outcome is variable, but forms of MCD that respond to steroids usually do not lead to chronic renal damage, whereas forms that are unresponsive to steroids may subsequently reveal themselves as FSGS. However, in a substantial number of patients the disease is recurrent and requires long-term immunosuppression, with significant morbidity because of side effects. Recent therapeutic advances, such as the use of anti-CD20 antibodies, have provided long-term remission off-therapy and suggest new hypotheses for disease pathogenesis.

Comparative differential proteomic analysis of minimal change disease and focal segmental glomerulosclerosis

Background

Minimal change disease (MCD) and primary focal segmental glomerulosclerosis (FSGS) are glomerular diseases characterized by nephrotic syndrome. Their diagnosis requires a renal biopsy, but it is an invasive procedure with potential complications. In a small biopsy sample, where only normal glomeruli are observed, FSGS cannot be differentiated from MCD. The correct diagnosis is crucial to an effective treatment, as MCD is normally responsive to steroid therapy, whereas FSGS is usually resistant.

The purpose of our study was to discover and validate novel early urinary biomarkers capable to differentiate between MCD and FSGS.

Methods

Forty-nine patients biopsy-diagnosed of MCD and primary FSGS were randomly subdivided into a training set (10 MCD, 11 FSGS) and a validation set (14 MCD, 14 FSGS). The urinary proteome of the training set was analyzed by two-dimensional differential gel electrophoresis coupled with mass spectrometry. The proteins identified were quantified by enzyme-linked immunosorbent assay in urine samples from the validation set.

Results

Urinary concentration of alpha-1 antitrypsin, transferrin, histatin-3 and 39S ribosomal protein L17 was decreased and calretinin was increased in FSGS compared to MCD. These proteins were used to build a decision tree capable to predict patient’s pathology.

Conclusions

This preliminary study suggests a group of urinary proteins as possible non-invasive biomarkers with potential value in the differential diagnosis of MCD and FSGS. These biomarkers would reduce the number of misdiagnoses, avoiding unnecessary or inadequate treatments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0452-6) contains supplementary material, which is available to authorized users.

The Clinical Course of Minimal Change Nephrotic Syndrome With Onset in Adulthood or Late Adolescence: A Case Series

BACKGROUND

Few studies have examined the treatment and outcome of adult-onset minimal change nephrotic syndrome (MCNS). We retrospectively studied 125 patients who had MCNS with onset in either adulthood or late adolescence. Presenting characteristics, duration of initial treatment and response to treatment, relapse patterns, complications, and long-term outcome were studied.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

Patients with new-onset nephrotic syndrome 16 years or older and a histologic diagnosis of MCNS in 1985 to 2011 were identified from pathology records of 10 participating centers.

OUTCOMES

Partial and complete remission, treatment resistance, relapse, complications, renal survival.

RESULTS

Corticosteroids were given as initial treatment in 105 (84%) patients. After 16 weeks of corticosteroid treatment, 92 (88%) of these patients had reached remission. Median time to remission was 4 (IQR, 2-7) weeks. 7 (6%) patients initially received cyclophosphamide with or without corticosteroids, and all attained remission after a median of 4 (IQR, 3-11) weeks. 13 (10%) patients reached remission without immunosuppressive treatment. One or more relapses were observed in 57 (54%) patients who received initial corticosteroid treatment. Second-line cyclophosphamide resulted in stable remission in 57% of patients with relapsing MCNS. Acute kidney injury was observed in 50 (40%) patients. Recovery of kidney function occurred almost without exception. Arterial or venous thrombosis occurred in 11 (9%) patients. At the last follow-up, 113 (90%) patients were in remission and had preserved kidney function. 3 patients with steroid-resistant MCNS progressed to end-stage renal disease, which was associated with focal segmental glomerulosclerosis lesions on repeat biopsy.

LIMITATIONS

Retrospective design, variable treatment protocols.

CONCLUSIONS

The large majority of patients who had MCNS with onset in adulthood or late adolescence were treated with corticosteroids and reached remission, but many had relapses. Cyclophosphamide resulted in stable remission in many patients with relapses. Significant morbidity was observed due to acute kidney injury and other complications. Progression to end-stage renal disease occurred in a few patients and was explained by focal segmental glomerulosclerosis.

Long-term outcomes for primary glomerulonephritis: New Zealand Glomerulonephritis Study

AIMS

Due to the paucity of studies focusing on primary glomerulonephritis, the second commonest cause of end-stage-kidney-disease in most of the developed world, we sought to review outcomes of these renal pathologies.

METHODS

We reviewed renal outcomes and mortality for primary glomerulonephritis patients enrolled in the New Zealand Glomerulonephritis Study between 1972 and 1983.

RESULTS

There were 765 patients with median follow-up of 30 years (range 0.1-42 years). They were predominantly New Zealand European, male and hypertensive. Poor renal outcomes and increased mortality were associated with hypertension, heavy proteinuria, impaired renal function and older age at diagnosis. Ethnicity was not significantly associated with progression to end-stage-kidney-disease although NZ Maori patients were at significantly increased risk of death. Patients with rapidly progressive glomerulonephritis had the highest risk of reaching end-stage-kidney-disease while the cumulative incidence of end-stage-kidney-disease was 20% and 30% for those with immunoglobulin-A nephropathy and membranous nephropathy respectively. Mortality risk was high for patients with rapidly progressive glomerulonephritis and anti-glomerular basement membrane disease. The era of diagnosis did not have much effect on outcomes except for patients with focal segmental glomerulosclerosis or immunoglobulin A nephropathy but this could be type II error.

CONCLUSION

We report one of the longest follow-up studies on biopsy-proven glomerulonephritides. Age, hypertension, and severity of chronic kidney disease at diagnosis were strong predictors of the development of end-stage-kidney-disease and death. The specific renal pathology had a profound impact upon prognosis and therefore should continue to drive efforts to find targeted therapeutic options for these glomerulonephritides.

Therapeutic variability in adult minimal change disease and focal segmental glomerulosclerosis

Background

Variability in the management of glomerulonephritis may negatively impact efficacy and safety. However, there are little/no data on actual variability in the treatment of minimal change disease (MCD)/focal segmental glomerulosclerosis (FSGS) in adults. We assessed Spanish practice patterns for the management of adult nephrotic syndrome due to MCD or FSGS. The absence of reasonably good evidence on treatment for a disease often increases the variability substantially. Identification of evidence–practice gaps is the first necessary step in the knowledge-to-action cyclical process. We aim to analyse the real clinical practice in adults in hospitals in Spain and compare this with the recently released Kidney Disease: Improving Global Outcomes clinical practice guideline for glomerulonephritis.

Methods

Participating centres were required to include all adult patients (age >18 years) with a biopsy-proven diagnosis of MCD or FSGS from 2007 to 2011. Exclusion criteria included the diagnosis of secondary nephropathy.

Results

We studied 119 Caucasian patients with biopsy-proven MCD (n = 71) or FSGS (n = 48) from 13 Spanish hospitals. Of these patients, 102 received immunosuppressive treatment and 17 conservative treatment. The initial treatment was steroids, except in one patient in which mycophenolate mofetil was used. In all patients, the steroids were given as a single daily dose. The mean duration of steroid treatment at initial high doses was 8.7 ± 13.2 weeks and the mean global duration was 38 ± 32 weeks. The duration of initial high-dose steroids was <4 weeks in 41% of patients and >16 weeks in 10.5% of patients. We did find a weak and negative correlation between the duration of whole steroid treatment in the first episode and the number of the later relapses (r = −0.24, P = 0.023). There were 98 relapses and they were more frequent in MCD than in FSGs patients (2.10 ± 1.6 versus 1.56 ± 1.2; P = 0.09). The chosen treatment was mainly steroids (95%). Only seven relapses were treated with another drug as a first-line treatment: two relapses were treated with mycophenolate and five relapses were treated with anticalcineurinics. A second-line treatment was needed in 29 patients (24.4%), and the most frequent drugs were the calcineurin inhibitors (55%), followed by mycophenolate mofetil (31%). Although cyclophosphamide is the recommended treatment, it was used in only 14% of the patients.

Conclusions

We found variation from the guidelines in the duration of initial and tapered steroid therapy, in the medical criteria for classifying a steroid-resistant condition and in the chosen treatment for the second-line treatment. All nephrologists started with a daily dose of steroids as the first-line treatment. The most frequently used steroid-sparing drug was calcineurin inhibitors. Cyclophosphamide use was much lower than expected.

Predictors of Relapse in Adult-Onset Nephrotic Minimal Change Disease

Minimal change disease (MCD) is a well-known benign primary glomerulonephritis because of its distinct rare tendency to progress to end-stage renal disease. However, factors associated with relapse in adults are not well known. We aimed to identify predictors of relapse in adult-onset MCD patients.A retrospective cohort of 195 patients with adult-onset primary MCD with nephritic syndrome and disease onset between 1979 and 2013 was followed up for >12 months. The number of relapses was counted and predictors of relapse were analyzed.A total of 195 patients were included. Median age at diagnosis was 38 years (IQR, 23-53 years) and 113 (57.9%) were men. During 81 months (IQR, 44-153 months) of follow-up, 92% of patients achieved remission after initial treatment. However, only 60 (32.8%) did not experience a relapse and 11 patients failed to remit. Among the remaining 124 patients, 65 experienced a relapse once or twice and 59 experienced a relapse more than twice. Younger onset age, increased severity of nephrotic features such as lower serum albumin levels and higher cholesterol level were associated with relapse. Interestingly, the grade of mesangial proliferation was lower in patients who experienced a relapse. Initial combined treatment with corticosteroids (CS) and cyclophosphamide reduced the number of relapses. In addition, patients with shorter treatment duration tended to experience relapse more often. Multivariate analysis showed that younger onset age, combined mesangial proliferation, initial treatment regimen, and treatment duration were independent risk factors for relapse. Progression to end-stage renal disease was developed in only a patient.In conclusion, more than two-thirds of adult-onset nephrotic MCD patients experienced relapse, although their renal progression was rare. Younger onset age, CS without cyclophosphamide treatment, and shorter treatment duration were independent risk factors for relapse in adult-onset MCD patients.

Adult Nephrotic Syndrome after Hematopoietic Stem Cell Transplantation: Renal Pathology is the Best Predictor of Response to Therapy

Nephrotic syndrome (NS) after allogeneic hematopoietic stem cell transplantation (HSCT) is a rare phenomenon usually associated with graft-versus-host disease (GVHD). This systematic review of post-HSCT NS cases reported in the literature aimed to identify risk factors and unique features of the disease in this clinical setting. One hundred sixteen cases of post-HSCT NS published in the English literature between 1988 and 2015 were revealed and analyzed. The median onset of NS was 20.5 months (range, 3 to 174) post-HSCT. NS development was associated with acute or chronic GVHD in 87.2% of cases. Membranous nephropathy (MGN) was the most frequent pathology (65.5%), followed by minimal change disease (MCD) (19%). Complete remission of the NS was achieved in 63.5% of patients (59.1% of MGN cases and 81.3% of MCD cases; P = .15). Patients presenting with MCD recovered at a median of 1.75 months (range, 1 to 12) and with MGN a median of 7 months (range, 1 to 53) (P = .001). NS was treated with corticosteroids alone in 16.8% of patients and with a combination of corticosteroids and other immunosuppressive agents in 73.5% of patients. Univariate analysis failed to identify a single predictive factor of response to therapy. In conclusion, post-HSCT NS usually develops concomitant to GVHD and is associated with high rates of response to therapy. Although most patients were treated with a combination of immunosuppressive drugs, single-agent therapy with steroids may be sufficient in some cases.

Glomerular Hypertrophy Is a Risk Factor for Relapse in Minimal Change Disease Patients

BACKGROUND/AIMS

Patients with minimal change disease (MCD) have a high relapse rate, which results in many complications. Identifying the risk factors for relapse is crucial, but little is known about these factors. Therefore, we performed the current study to determine the factors related to relapse in this patient population.

METHODS

We retrospectively analyzed 51 adult patients with biopsy-proven primary MCD treated between 2003 and 2013. The demographic, physiologic, laboratory and therapeutic data were gathered from the electronic medical records database. Lesions of the glomerulus, tubulointerstitium and vasculature were analyzed for associations with relapse.

RESULTS

During a median 50.9 months, 96.1% (49 of 51) of patients had achieved complete remission, and the rest ultimately achieved at least partial remission. A total of 56.9% (29 of 51) patients experienced at least 1 episode of relapse after the first remission. Patients with relapse had a higher rate of glomerular hypertrophy (GH; 34.5%) than those without relapse (9.1%; p < 0.05). After adjusting for confounders, GH was associated with increased odds of relapse (OR 15.992; 95% CI 1.537-166.362; p = 0.02). In a subgroup analysis according to median age, sex and tubulointerstitial (TI) lesions, the association between GH and relapse was evident only in men and in the group with TI lesions.

CONCLUSION

GH is associated with relapse in adult patients with MCD, particularly in men and in those with TI lesions. Frequent monitoring and early intervention are needed in these groups. Future large prospective cohort studies are needed to confirm the study results.

Comparison of Glomerular Transcriptome Profiles of Adult-Onset Steroid Sensitive Focal Segmental Glomerulosclerosis and Minimal Change Disease

Objective

To search for biomarkers to differentiate primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD).

Methods

We isolated glomeruli from kidney biopsies of 6 patients with adult-onset steroid sensitiveFSGS and 5 patients with MCD, and compared the profiles of glomerular transcriptomes between the two groups of patients using microarray analysis.

Results

Analysis of differential expressed genes (DEGs) revealed that up-regulated DEGs in FSGS patients compared with MCD patients were primarily involved in spermatogenesis, gamete generation, regulation of muscle contraction, response to unfolded protein, cell proliferation and skeletal system development. The down-regulated DEGs were primarily related to metabolic process, intracellular transport, oxidation/reduction andestablishment of intracellular localization. We validated the expression of the top 6 up-regulated and top 6 down-regulated DEGs using real-time PCR. Membrane metallo-endopeptidase (MME) is a down-regulated gene that was previously identified as a key gene for kidney development. Immunostaining confirmed that the protein expression of MME decreased significantly in FSGS kidneys compared with MCD kidneys.

Conclusions

This report was the first study to examine transcriptomes in Chinese patients with various glomerular diseases. Expressions of MME both in RNA and protein level decreased significantly in glomeruli of FSGS kidneys compared with MCD kidneys. Our data suggested that MME might play a role in the normal physiological function of podocytes and a decrease in MME expression might be related to podocyte injury. We also identified genes and pathways specific for FSGS versus MCD, and our data could help identify potential new biomarkers for the differential diagnosis between these two diseases.

A series of patients with minimal change nephropathy treated with rituximab during adolescence and adulthood

Background

The treatment of immune suppression dependent minimal change nephropathy (MCN) can be challenging and frequently leads to serious complications. In paediatric patients, successful treatment with rituximab is described in steroid-dependent MCN. There is limited information about the potential efficacy of rituximab for the treatment of MCN in adults and adolescence. We describe our experience with rituximab in adolescent and adult patients with immune suppression dependent MCN.

Results

Ten adolescents and adults with immune suppression dependent MCN and therapy related complications were treated with rituximab. At a mean age of 26 years, about 10.5 years after first presentation, they received two doses of rituximab (375 mg/m²). Maintenance immunosuppressive medication was stopped. After a mean follow-up of 43 months, three patients had four relapses. Three relapses were successfully retreated with rituximab again, after induction therapy with 60 mg prednisone per day. Rituximab was well tolerated and no infectious complications were recorded.

Conclusion

Treatment with rituximab induces a long-term remission of immune suppression dependent MCN in adolescents and adults. A timely treatment with rituximab could be considered to limit side effects of immunosuppressive medication.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1255-0) contains supplementary material, which is available to authorized users.