Focal segmental glomerulosclerosis in idiopathic membranous glomerulonephritis: a clinico-pathological and stereological study

[Idiopathic membranous nephropathy with focal segmental sclerosis]

AIM

To evaluate the clinical and pathological features and prognosis of idiopathic membranous nephropathy (IMN) with focal segmental sclerosis (FSGS) in a group of Russian patients.

MATERIALS AND METHODS

101 patients with morphologically verified IMN were enrolled in our single-center cohort retrospective study. The patients were divided into IMN group and IMN+FSGS group. The primary and secondary outcomes were analyzed in 59 patients, which had follow-up data for period more than 6 months.

RESULTS

At the time of renal biopsy the median age was 46.0 (33.0; 55.0) years and the median follow-up was 6.8 (4.0; 15.6) months. Secondary FSGS was revealed in 15 (14.9%) patients with IMN. The IMN and IMN+FSGS groups did not differ in gender, age of onset IMN and age of renal biopsy. In the IMN+FSGS group proteinuria was higher and estimated glomerular filtration rate was lower than that in the IMN group (p<0.05). The systolic arterial pressure and creatinine levels in the IMN+FSGS group were slightly higher than in the IMN group, but the difference was not significant. Anti-PLA2R positivity was similar in both groups. Chronic kidney disease (CKD) progression was observed in 10/52 (19.2%) and 5/7 (71.4%) patients in IMN and IMN+FSGS groups, respectively. In a multivariate Cox regression model, age of renal biopsy (odds ratio - OR 1.12, 95% confidence interval - CI 1.03-1.22; р=0.07), FSGS (OR 0.05, 95% CI 0.01-0.34; р=0.002) и response to initial course of immunosuppression (OR 0.33, 95% CI 0.12-0.95; р=0.039) were associated with the CKD progression.

CONCLUSION

In patients with IMN secondary FSGS is associated with a greater severity of proteinuria and a decrease in estimated glomerular filtration rate, and is also an independent factor of the CKD progression.

Aggressive treatment may be needed for idiopathic membranous nephropathy with focal segmental glomerulosclerosis lesions

OBJECTIVE

The purpose of this study was to analyze the clinical, pathological, prognostic features and treatment response of the coexistence of focal segmental glomerulosclerosis lesions with idiopathic membranous nephropathy.

METHODS

This is a two-center retrospective cohort study. Patients of idiopathic membranous nephropathy were enrolled and divided into two groups with or without focal segmental glomerulosclerosis lesions according to the renal biopsy. Laboratory data and pathological manifestation were compared. Renal phospholipase A2 receptor was detected by immunofluorescence. During the follow-up, the effects of different therapies and renal function were estimated.

RESULTS

A total of 236 patients were finally enrolled in this study, of which 60 and 176 idiopathic membranous nephropathy patients were enrolled in the FSGS+ and FSGS- groups, respectively. The FSGS+ group showed a higher percentage of hypertension history (38.3 vs. 20.0%, p=0.004), with a significantly higher level of systolic pressure [137 (120, 160) mmHg vs. 130 (120, 140) mmHg, p=0.009]. Main laboratory findings, including serial albumin (20.4±7.8 g/L vs. 24.5±6.7 g/L, p<0.001), 24-h proteinuria [5.61 (3.10, 7.87) g/day vs. 3.82 (2.31, 5.79) g/day, p=0.002], serial creatinine [80.8 (65.8, 97.9) μmol/L vs. 72.0 (58.7, 84.9) μmol/L, p=0.003], and estimated glomerular filtration rate [86 (66, 101) mL/min/1.73 m2 vs. 95 (81, 108) mL/min/1.73 m2, p=0.007] showed significant differences between the two groups. Pathologically, patients with focal segmental glomerulosclerosis lesions appeared with a higher percentage of crescents, a more severe degree of interstitial fibrosis, and a higher level of membranous nephropathy stage. Renal phospholipase A2 receptor showed a relatively lower positive rate of only 75.0% in the FSGS+ group in comparison with the positive rate of 90.3% in the FSGS- group (p=0.031). The prognosis was generally similar between the two groups. Among patients who were given non-immunosuppression treatment, those with focal segmental glomerulosclerosis lesions took a relatively longer period of time to achieve complete remission (29.3±7.0 m vs. 15.4±8.9 m, p=0.025) and experienced a higher rate of renal function deterioration (37.5 vs. 5.4%, p=0.033) compared with the other ones. While among those receiving immunosuppression treatment, both groups received similar remission rates.

CONCLUSION

Compared with FSGS- group, idiopathic membranous nephropathy with focal segmental glomerulosclerosis lesions represented more severe nephrotic syndrome and worse renal function. In view of the renal function decline during the follow-up, more aggressive treatment with the use of immunosuppressants should be considered for idiopathic membranous nephropathy patients with focal segmental glomerulosclerosis lesions.

Clinical characteristics and prognosis of patients with idiopathic membranous nephropathy with kidney tubulointerstitial damage

BACKGROUND

To investigate the clinical and kidney pathological features and prognosis of idiopathic membranous nephropathy (IMN) with kidney tubulointerstitial damage (TID).

METHODS

Based on the presence or absence of kidney TID by kidney biopsy, 300 patients diagnosed with IMN were categorized into non-TID (TID-) and tubulointerstitial injury (TID+) groups. The clinical and pathological data were analyzed retrospectively. All patients were followed up for 6-24 months after treatment with glucocorticoids (GCs) combined with cyclophosphamide or GCs combined with calcineurin inhibitors (CNIs) to observe treatment effects on patient prognosis.

RESULTS

The patients in the TID + group were older and more likely to be male. The 24-h urine protein, blood urea nitrogen, serum creatinine, cystatin C, β2-microglobulin, and antiphospholipase A2 receptor antibody levels were higher than those in the TID - group and the pathological manifestations were more severe. After 1 year of follow-up, the overall response rate (complete response + partial response) in the TID + group was lower (66.67% vs. 80.89%, p = .022) than in the other. After combined GC and CNI therapy, the complete remission rate in the TID + group was significantly lower than that in the TID - group (13.79% vs. 35.46%, p = .022). The 24-h urine protein level was an independent risk factor for worsening kidney condition (p = .038).

CONCLUSION

Patients with IMN with TID have more severe clinical manifestations and pathological damage and lower remission rates. IMN with TID is a risk factor for worsening kidney condition; however, it is not an independent risk factor.

Calcineurin inhibitors or cyclophosphamide in the treatment of membranous nephropathy superimposed with FSGS lesions: a retrospective study from China

BACKGROUND

Cyclophosphamide (CTX) and calcineurin inhibitors (CNIs) based regimens are recommended as immunosuppressive therapies for patients with idiopathic membranous nephropathy (IMN). Focal and segmental glomerular sclerosis (FSGS) lesions, which are common in membranous nephropathy (MN), are poor predictors of outcome. This study compared the differences of prognosis between two regimens in patients with IMN combined with FSGS lesions.

METHODS

This retrospective study enrolled 108 patients with biopsy-proven IMN, accompanied with FSGS lesions, nephrotic syndrome and an estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m2 who were treated with CTX or CNIs. We used propensity score matching (PSM) for balancing the confounding variables.

RESULTS

During follow-up, 10 patients (10/55 [18.2%]; nine males) in the CNIs group showed a 50% decline in eGFR; eight had a not otherwise specified variant. Patients initially treated with CNIs had a significantly higher risk of progression to the primary outcome and a lower probability of complete or total remission. The relapse rate was higher in patients who initially received CNIs- than in those who received CTX-based treatment. Before PSM, age and 24-h urine protein level differed significantly between the groups. The PSM model included data from 72 patients. Worse outcomes were also noted among patients who initially received CNIs than those who received CTX-based treatments after matching.

CONCLUSIONS

Patients with MN combined with FSGS lesions have a higher risk of renal functional decline and a higher rate of relapse after CNIs than after CTX therapy.

Comparative analysis of the efficacy of different treatments for idiopathic membranous nephropathy: a retrospectively real-world study

BACKGROUND

This study aimed to explore the clinical efficacy of different treatment regimens for idiopathic membranous nephropathy (IMN).

METHODS

Patients with IMN were retrospectively analyzed by dividing into two groups: glucocorticoids combined with cyclophosphamide group (GC + CYC) and glucocorticoids combined with calcineurin inhibitor group (GC + CNIs). After 1 year of treatment, those who found that the initial treatment was not effective were switched to another regimen. Patients continued to be followed up for at least 1 year to observe the treatment effects of different treatment regimens.

RESULTS

This study found that the rate of complete and partial remission (CR + PR) in the GC + CYC and GC + CNIs groups was 76.19 vs. 82.63% after 1 year of follow-up (p > .05). In the GC + CYC and GC + CNIs groups, 27.78 and 11.95% of the patients switched treatment regimens, respectively. After 2 years of follow-up, the CR + PR rate was significantly higher in the change to GC + CNIs group after the switch compared to before the switch (80.00 vs. 31.43%, p < .001). It was also significantly higher in the change to GC + CYC group compared to before the switch (68.42 vs. 31.58%, p = .023). The recurrence rate was significantly higher in the maintain GC + CNIs and change to GC + CNIs groups than in the maintain GC + CYC and change to GC + CYC groups (25.14 vs 6.36%, p < .001). The disengagement rate from immunotherapy was significantly higher in the maintain GC + CYC group and the change to GC + CYC group than in the maintain GC + CNIs group and the change to GC + CNIs group (76.36% vs 29.71%, p < .001). High titer of anti-phospholipase A2 receptor (anti-PLA2R) antibody (95%CI: 0.199-0.947, p = .036) and serum C3 (95%CI: 0.030-0.570, p = .007) were independent risk factors, while serum IgG (95%CI: 1.000-1.331, p = .050) was a favorable factor for achieving CR. Anti-PLA2R antibody was the independent risk factor that affected the worse renal condition (p = .023).

CONCLUSIONS

Timely change of treatment regimen can significantly enhance therapeutic effect. Compared with patients administered with CYC, those administered with CNIs were less likely to leave treatment and had a higher recurrence rate.

Non-glomerular Tip Lesion Focal Segmental Glomerulosclerosis as a Negative Predictor in Idiopathic Membranous Nephropathy

Objective

To assess the significance of focal segmental glomerulosclerosis (FSGS) variants on clinicopathological characteristics and short-term outcomes in idiopathic membranous nephropathy (IMN) patients.

Methods

The clinicopathological data of 146 IMN patients diagnosed between December 2016 and March 2019 in our center were collected and analyzed. These patients were divided into the pure IMN group, IMN with glomerular tip lesion (GTL) group, and IMN with non-GTL FSGS group.

Results

The IMN with non-GTL FSGS and IMN with GTL groups both had higher proportions of patients with hypertension, lower serum albumin, and severe proteinuria, while the IMN with non-GTL FSGS group additionally showed higher blood pressure and serum cholesterol, and lower serum IgG than the IMN group (all P<0.05). As for pathology, the IMN with non-GTL FSGS group had higher proportions of patients with acute tubular injury and moderate to severe chronic injuries than the IMN group (all P<0.05). In the IMN, IMN with GTL, and IMN with non-GTL FSGS groups, the overall one-year remission rates were 81.6%, 76%, and 58.8%, respectively. Furthermore, the IMN with non-GTL FSGS group showed the lowest cumulative incidence to reach remission within one year. Multivariate Cox logistic analysis demonstrated that higher level of serum anti-M-type phospholipase A2 receptor antibody and the existence of non-GTL FSGS lesion were independent predictors for no remission in IMN patients.

Conclusion

The non-GTL FSGS lesion was a novel negative predictor in IMN and should be taken into account in the management of IMN.

Clinicopathological Characteristics and Outcomes of PLA2R-Associated Membranous Nephropathy in Seropositive Patients Without PLA2R Staining on Kidney Biopsy

RATIONALE & OBJECTIVE

Phospholipase A₂ receptor (PLA₂R)-associated membranous nephropathy (MN) with circulating serum autoantibodies to PLA₂R (SAb⁺) but no deposits of PLA₂R antigen in glomerular tissue by immunofluorescence (GAg^-) has been reported. However, little is known about the clinicopathological characteristics or prognosis of this subtype of MN.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

130 SAb⁺ patients in China with biopsy-proven MN who had follow-up data and received immunosuppressive therapy. The median follow-up was 16 (IQR, 9-25) months.

PREDICTOR

PLA₂R antigen detection by immunofluorescence staining of kidney biopsy specimens.

OUTCOMES

Complete remission (CR) was defined as proteinuria levels <0.3 g/d and a >50% decrease compared with a previously established baseline. Partial remission (PR) was defined as proteinuria levels <3.5 g/d and a >50% decrease compared with a previously established baseline. The kidney function outcome was defined as a >40% decrease in estimated glomerular filtration rate (eGFR) at the end of the study compared with baseline.

ANALYTICAL APPROACH

Kaplan-Meier analysis of PR and CR comparing SAb⁺/GAg⁺ and SAb⁺/GAg^- patients. Cox proportional hazards models to examine these associations were adjusted for confounders.

RESULTS

Among 130 SAb⁺ patients with PLA₂R-associated MN, 18 were GAg^-. Compared with SAb⁺/GAg⁺ patients, those who were SAb⁺/GAg^- presented with more severe kidney injury as evidenced by higher SAb titer, greater proteinuria, lower serum albumin concentrations, lower eGFR (all P < 0.05), and more severe disease with higher chronicity scores (P < 0.001) on kidney biopsies. SAb⁺/GAg^- patients exhibited a significantly lower probability of PR (P < 0.001) and CR (P = 0.03) and were more likely to experience a >40% decrease in eGFR (P = 0.008) than patients who were SAb⁺/GAg⁺. After adjusting for clinical and pathologic variables available at the time of biopsy, compared with SAb⁺/GAg⁺ patients, SAb⁺/GAg^- patients had a lower rate of experiencing remission (hazard ratio, 0.32 [95% CI, 0.15-0.68]; P = 0.003) and a higher rate of the >40% eGFR decrease outcome (hazard ratio, 7.66 [95% CI, 1.54-38.08]; P = 0.01).

LIMITATIONS

Retrospective study, small sample size, and lack of a uniform approach to treatment.

CONCLUSIONS

Seropositive PLA₂R-associated MN without PLA₂R staining on kidney biopsy may represent a distinct clinical subtype with more severe disease and a worse prognosis. GAg^- is independently associated with poor response to treatment and >40% eGFR decrease in seropositive PLA₂R-associated MN.

Acute kidney injury in idiopathic membranous nephropathy with nephrotic syndrome

BACKGROUND AND OBJECTIVES

The impact of acute kidney injury (AKI) on the progression of renal function in idiopathic membranous nephropathy (iMN) with nephrotic syndrome (NS) patients have not yet been reported, we sought to investigate the incidence, clinical features and prognosis of AKI in iMN with NS patients and determine clinical predictors for progression from AKI to advanced chronic kidney disease (CKD) stage.

METHODS

We analyzed clinical and pathological data of iMN with NS patients retrospectively collected from Jan 2012 to Dec 2018. The primary renal endpoint was defined as persistent eGFR <45ml/min per 1.73 m² more than 3 months. Comparisons of survival without primary renal endpoint were performed by Kaplan-Meier curves and log-rank test. Univariate and multivariate Cox proportional hazard models were constructed to determine independent variables associated with primary renal endpoint .

RESULTS

434 iMN with NS patients were enrolled. The incidence of AKI 1 stage, AKI 2 stage and AKI 3 stage was 23.1, 4.8 and 0.7% respectively. 66 (53.2%) patients with AKI had complete renal function recovery and 42 (33.9%) patients with AKI reached primary renal endpoint. Survival without primary renal endpoint was worse in AKI patients than No AKI patients (67.1 ± 5.3 and 43.7 ± 7.3% vs 99.5 ± 0.5 and 92.5 ± 4.2% at 2 and 4 years,p < 0.001). AKI was independently associated with primary renal endpoint, with an adjusted hazard ratio(HR) of 25.1 (95%CI 7.7-82.1, p < 0.001).

CONCLUSIONS

AKI was usually mild and overlooked in iMN patients with NS, but it had a strong association with poor clinical outcomes and was an independent risk factor for CKD progression.

Clinicopathologic characteristic and prognosis in idiopathic membranous nephropathy patients with focal segmental sclerosis lesion: A retrospective observational study

To explore the clinicopathological characteristics and prognosis of idiopathic membranous nephropathy (IMN) with focal segmental sclerosis lesions (FSL). A total of 70 IMN patients with FSL (FSL+group) were enrolled in this study, and 140 patients were randomly selected by age and sex matching as disease controls (FSL-group). The clinical and renal histopathological data on renal biopsy and clinical data of patients regularly followed were collected. Serum anti-phospholipase A2 receptor (PLA2R) autoantibody, thrombospondin type-1 domain-containing 7A (7A) autoantibody, glomerular PLA2R and 7A expression, and IgG4 deposition were detected. First, the clinical and pathological significance of IMN combined with the FSL group was analyzed. Whether FSL is a risk factor for renal outcomes was further analyzed. 1. Compared with the FSL- group, patients in the FSL+ group had a significantly higher incidence of hypertension and a longer duration of hypertension as well as higher levels of systolic blood pressure, serum creatinine, serum triglycerides, serum cholesterol, 24-hour urinary protein excretion, and lower eGFR and urine osmotic pressure. Patients in the FSL+ group had an increased frequency of Churg stage III and more severe glomerulosclerosis and interstitial fibrosis. The remission rate was significantly lower in the FSL+ group than in the FSL- group (50.0% vs 75.9%, P = .027). 2. Multivariate Cox regression analysis showed that FSL (HR = 3.01, 95%CI = 1.07–8.52, P = .038) was an independent risk factor for progression of renal function deterioration, and FSL (HR = 3.25, 95%CI = 1.43–7.38, P = .005) and high levels of serum anti-PLA2R antibody (HR = 1.89, 95%CI = 1.27–2.82, P = .002) were independent risk factors for nonremission of IMN. IMN patients who developed FSL had more severe clinical and pathological characteristics than those without FSL. FSL was an independent risk factor for poorer prognosis. When the appearance of FSL in IMN patients with a high level of serum anti-PLA2R antibody, the treatment needs to be more aggressive to promote remission and to delay the progression of renal function.

Seropositive PLA2R-associated membranous nephropathy but biopsy-negative PLA2R staining

BACKGROUND

Serum phospholipase A2 receptor (PLA2R) antibody (SAb) and glomerular deposits of PLA2R antigen (GAg) have been tested widely in idiopathic membranous nephropathy (MN). Recently, we noticed a special form of PLA2R-associated MN with positive circulating PLA2R antibody but negative PLA2R deposits in the glomeruli by immunofluorescence on frozen tissue (IF-F). The significance of this form of PLA2R-associated MN is yet to be elucidated. This study aimed to explore the clinicopathological features of these PLA2R-associated MN patients.

METHODS

This study enrolled 229 biopsy-proven PLA2R-associated MN patients with SAb+. SAb was measured by enzyme-linked immunosorbent assay, and GAg was detected by IF-F. These patients were divided into SAb+/GAg+ and SAb+/GAg- groups. Clinicopathological characteristics of SAb+/GAg+ and SAb+/GAg- PLA2R-associated MN patients were compared. PLA2R antigens of 19 SAb+/GAg- PLA2R-associated MN patients were verified by immunohistochemistry on paraffin tissue (IHC-P).

RESULTS

Among 229 SAb+ PLA2R-associated MN patients, 210 (91.70%) were GAg+ and 19 (8.3%) were GAg-. These 19 SAb+/GAg- PLA2R-associated MN patients presented positive PLA2R deposits by IHC-P. Compared with SAb+/GAg+ PLA2R-associated MN patients, SAb+/GAg- PLA2R-associated MN patients had higher levels of serum PLA2R antibody (P = 0.004), increased proteinuria (P = 0.008), lower serum albumin (P = 0.019), more prominent chronic pathological lesions in terms of glomerulosclerosis score (P = 0.025), interstitial fibrosis score (P = 0.016), tubular atrophy score (P = 0.010) and total renal chronicity score (P = 0.010), and were more likely to be accompanied by focal segmental glomerulosclerosis (P = 0.014). Higher SAb level was associated with the total renal chronicity score (odds ratio per 100 RU/mL, 1.16; 95% confidence interval 1.01-1.33; P = 0.033).

CONCLUSIONS

PLA2R-associated MN patients with seropositive PLA2R antibody but negative PLA2R deposits in the glomeruli by IF-F have higher levels of SAb and worse clinicopathological manifestations compared with their double-positive counterparts. IHC-P can be an alternative technique to reveal PLA2R glomerular deposits.

Clinical and pathological features of idiopathic membranous nephropathy with focal segmental sclerosis

Background

The goal of this study was to investigate the clinical and pathological features and prognosis of idiopathic membranous nephropathy (IMN) with focal segmental lesions.

Methods

In our hospital, 305 patients with nephrotic syndrome confirmed as IMN by renal biopsy were divided into a non-focal segmental lesion group (FSGS- group) and a focal segmental glomerulosclerosis (FSGS) group (FSGS+ group) and retrospectively analyzed. In all, 180 patients were followed for periods ranging from 6 months to 2 years. The general clinicopathological data of both groups were compared, and the effects of different treatment schemes on the prognosis of both groups were observed.

Results

The FSGS+ group had a longer disease course, higher blood pressure levels, and higher serum creatinine and β₂-microglobulin levels than did the FSGS- group (all P < 0.05). Pathologically, the FSGS+ group had increased glomerular sclerosis, glomerular mesangial hyperplasia, and acute and chronic tubular lesion rates (all P < 0.05). The remission rate was lower in the FSGS+ group than in the FSGS- group (64.7% vs 82.2%) and, among patients in the FSGS+ group, was lower in patients treated with calmodulin inhibitors than in those treated with cyclophosphamide (P < 0.01). Survival analysis showed that the FSGS+ group had a poor prognosis (χ² = 4.377, P = 0.036), and risk factor analysis suggested that age at renal biopsy (P = 0.006), 24-h urinary protein quantity (P = 0.01), chronic tubulointerstitial lesions (P = 0.055), and FSGS lesions (P = 0.062) were risk factors for worsening renal condition; furthermore, 24-h urinary protein quantity was an independent risk factor for worsening renal condition.

Conclusions

Membranous nephropathy with FSGS is a risk factor, but not an independent risk factor, for IMN. Patients with membranous nephropathy with FSGS often present hypertension and tubule injury. The nonselective drug cyclophosphamide is preferred, and calcineurin inhibitors should be used with caution.

Histological grading in primary membranous nephropathy is essential for clinical management and predicts outcome of patients

Aims

Diagnosis of primary membranous nephropathy (PMN) is mainly based on immunofluorescence/immunohistochemistry findings. However, assessment of specific features on optical microscopy can help to estimate the severity of the disease, guide treatment and predict the response. The aim of this study was to identify, classify and grade the precise histological findings in PMN to predict renal function outcome and guide treatment.

Methods and results

Histological parameters, including focal segmental sclerosis (FSGS), tubular atrophy (TA), interstitial fibrosis (IF) and vascular hyalinosis (VH), were re‐evaluated in 752 patients with PMN. Their predictive value was estimated separately, and also in a combination score (FSTIV) graded from 0 to 4. Finally, the impact of histology was assessed in the response to immunosuppressive treatment. Mean age of patients was 53.3 (15–85) years and most presented with nephrotic syndrome. FSGS was present in 32% and VH in 51% of the patients, while TA and IF were graded as stage ≥1 in 52% and 51.4%, respectively. The follow‐up period was 122.3 (112–376) months. FSGS, TA and IF and VH were associated with impaired renal function at diagnosis (P = 0.02, P < 0.0001, P = 0.001 and P = 0.02, respectively) and at the end of follow‐up (P = 0.004, P < 0.0001, P < 0.0001 and P = 0.04, respectively). In multiple regression and binary logistic analysis, the presence of FSGS and degree of TA were the most significant parameters predicting renal function outcome, defined either by eGFR (end), FSGS (r = 0.6, P < 0.0001) and TA (r = 0.6, P < 0.0001), or by the endpoint of >50% eGFR reduction, FSGS (P = 0.001) and TA (P = 0.02). Also, patients presented with FSGS, IF, VH and/or with FSTIV > 1 could benefit from immunosuppression, regardless of clinical presentation.

Conclusions

The presence and degree of four histological indices, FSGS, VH, TA and IF, assessed separately or in combination, and FSTIV score not only predict renal function outcome after long‐term follow‐up, but can also help in the choice of appropriate treatment. Decisions concerning immunosuppressive treatment can be guided by pathology regardless of clinical findings.

Focal segmental glomerulosclerosis, excluding atypical lesion, is a predictor of renal outcome in patients with membranous nephropathy: a retrospective analysis of 716 cases

BACKGROUND

Focal segmental lesions (FSLs) are not uncommon in idiopathic membranous nephropathy (IMN). The reported percentage of IMN patients with focal segmental glomerulosclerosis (FSGS) lesions varies widely between studies. The objective of this study was to differentiate atypical FSL (aFSL) from typical FSGS in IMN and to analyse the clinicopathological predictors of primary outcome of IMN patients.

METHODS

A total of 716 patients with biopsy-proven IMN between January 1, 2007 and December 31, 2017 were enrolled in the study. An atypical focal segmental lesion was defined as pure synechia, segmental hyperplasia of podocytes or thickening of the GBM accompanied by proliferation of the mesangial matrix, and absence of typical FSGS. The patients were divided into three groups: patients without FSL (FSL^-), patients with typical FSGS (FSGS⁺), and patients with aFSL (aFSL⁺).The primary outcome was a 50% decline in the initial estimated glomerular filtration rate or end-stage renal disease (ESRD) incidence. Secondary outcomes included all-cause death and ESRD.

RESULTS

FSGS was present in 174 patients, while aFSL was noted in 161 patients. Systolic blood pressure was higher in both aFSL⁺ group and FSGS⁺ groups compared with the FSL^- group. IMN patients without FSL and with aFSL had lower serum creatinine levels than IMN patients with FSGS. Both the FSGS⁺ and aFSL⁺ groups had higher levels of proteinuria and lower albumin levels than the FSL^- group. Renal tissue lesions, including tubulointerstitial fibrosis, glomerular obsolescence, and vascular sclerosis were significantly more severe in the FSGS⁺ group. Cox multivariate analysis showed that older age ≥ 60 years, eGFR< 60 ml/(min·1.73m²), tubulointerstitial fibrosis area ≥ 15% and FSGS at biopsy were independent risk factors for the primary outcome.

CONCLUSIONS

No significant difference in outcome was found between the FSL^- and aFSL⁺ groups, although the patients with aFSL had lower levels of serum albumin and eGFR, higher level of urinary protein, more severe renal lesions with proliferation of the mesangial area,tubulointerstitial fibrosis and vascular sclerosis. FSGS, excluding atypical lesions, was an independent predictor of the primary outcome.

Focal and Segmental Glomerulosclerosis and Membranous Nephropathy overlapping in a patient with Nephrotic Syndrome: a case report

Introduction:

Some cases of membranous nephropathy (MGN) present focal segmental glomerulosclerosis (FSGS) typically associated with disease progression. However, we report a case of a patient who seemed to have MGN and FSGS, both primary.

Case presentation:

A 17-year-old female, Caucasian, presenting lower extremity edema associated with episodes of foamy urine and high blood pressure, had physical and laboratorial exams indicating nephrotic syndrome. A renal biopsy was performed and focal and segmental glomerulosclerosis were observed under light microscopy in some glomeruli presented as tip lesion, and in others it was accompanied by podocyte hypertrophy and podocyte detachment in urinary space, compatible with podocytopathy FSGS. Besides, there were thickened capillary loops with basement membrane irregularities due to "spikes" compatible with MGN stage II. Immunofluorescence showed finely granular IgG, IgG4, and PLA2R deposits in capillary loops and, in electron microscopy, subepithelial deposits and foot process effacement. These morphological findings are compatible with FSGS and MGN stage II.

Conclusions:

In the present case, clinical and morphological characteristics showed a possible overlap of primary FSGS and MGN as focal and segmental glomerulosclerosis does not seem to be related with MGN progression but with the podocytopathy FSGS.

NEPHROPATHIES IN THE EUROPEAN CAPTIVE CHEETAH (ACINONYX JUBATUS) POPULATION

According to previous studies in captive cheetah ( Acinonyx jubatus ) populations, one of the most threatening diseases besides amyloidosis, myelopathy, veno occlusive disease, and gastritis, is renal failure. Contrary to captive cheetahs in North America and South Africa, morphological data concerning renal lesions in the cheetah European Endangered Species Program (EEP) are lacking. This study details the histological characterization as well as immunohistochemical and morphometrical analysis of nephropathies in 35 captive cheetahs from the EEP, which were necropsied between 1985 and 2003. Examination of paraffin- and glycolmethacrylate-methylmethacrylate (GMA-MMA) embedded kidney samples by light microscopy revealed glomerulonephritis in 91%, with a high prevalence for glomerulosclerosis and glomerulonephritis with the histologic pattern of membranous glomerulonephritis (77%). Besides these predominating glomerulopathies, a wide range of other renal lesions, like acute tubular necrosis, interstitial nephritis, calcinosis, and amyloidosis, were present. Pathological expression of collagen type IV, complement C3, fibronectin, and IgG was demonstrated in the glomeruli of the cheetah kidneys with the use of the avidin-biotin complex method. Morphometrical analysis was performed on GMA-MMA embedded kidney samples to obtain glomerulosclerosis index and glomerulosclerosis incidence.

Patients With Combined Membranous Nephropathy and Focal Segmental Glomerulosclerosis Have Comparable Clinical and Autoantibody Profiles With Primary Membranous Nephropathy: A Retrospective Observational Study

Patients with combined membranous nephropathy (MN) and focal segmental glomerulosclerosis (FSGS) have been reported with different clinical significance. Investigations on the possible mechanisms of the combined glomerular lesions are necessary but scarce. Twenty patients with both MN and FSGS lesions were enrolled in the study. Sixty-five patients with primary MN and 56 patients with primary FSGS were used as disease controls. Clinical data on renal biopsy and during follow-up were collected. Circulating anti-phospholipase A2 receptor (PLA2R) antibody, glomerular PLA2R expression, IgG4 deposition, and soluble urokinase receptor (suPAR) levels were detected. We found that patients with combined lesions presented with older age, less proteinuria, higher albumin, and better renal function on biopsy. These were comparable to the patients with primary MN, but differed from the patients with primary FSGS. Patients with combined lesions showed higher stages of MN, no cellular variant on FSGS classification, and more common (100.0%) tubulointerstitial injury than both primary MN and primary FSGS patients. In the patients with combined lesions, 80.0% had circulating anti-PLA2R antibody and 68.4% had IgG4 predominant deposition in glomeruli, which were comparable to primary MN. The patients with combined lesions had significantly lower urinary suPAR concentrations, than the primary FSGS patients (315.6 ± 151.0 vs 752.1 ± 633.9 pg/μmol; P = 0.002), but similar to the primary MN patients (267.9 ± 147.5 pg/μmol). We conclude that patients with combined MN and FSGS may share the same underlying pathogenesis with primary MN. The FSGS lesion might be secondary to primary MN.

Glomerular endothelial cell injury and focal segmental glomerulosclerosis lesion in idiopathic membranous nephropathy

Background

Focal segmental glomerulosclerosis (FSGS) lesions have often been discussed as a negative predictor in idopathic membranous nephropathy (MN). The mechanism of the development of FSGS lesion in MN is still uncertain.

Methods

From 250 cases of MN, 26 cases contained FSGS lesion. We compared the clinicopathological characteristics between MN cases with FSGS lesion [MN-FSGS(+)] and MN without FSGS lesion [MN-FSGS(−)], matched for gender, age, stage of MN.

Results

The glomerular filtration rate (eGFR) was significantly lower in MN-FSGS(+) cases compared to MN-FSGS(−), although nephrotic syndrome, hematuria, and systolic blood pressure levels were not significantly different between the two groups. Pathologically, glomeruli in MN-FSGS(+) cases showed narrowing and loss of glomerular capillaries with separating from GBM or disappearance of CD34+ endothelial cells, and accumulation of extracellular matrix (ECM) in capillary walls, indicating the development of glomerular capillary injury. These findings of endothelial injury were seen even in MN-FSGS(−) cases, but they were more prominent in MN-FSGS(+) than MN-FSGS(−) by computer assessed morphometric analysis. In MN-FSGS(+) cases, 44 out of 534 glomeruli (8.2%) contained FSGS lesions (n = 31, NOS lesion; n = 13, perihilar lesion). Significant thickness of GBM with ECM accumulation was evident in MN-FSGS(+) cases. Podocyte injury with effacement of foot processes was also noted, but the expression of VEGF on podocytes was not different between the two groups, which suggests that the significant thickness of capillary walls may influence the function of VEGF from podocyte resulting in the glomerular capillary injury that contribute to the development of FSGS lesion in MN.

Conclusion

Glomerular capillary injury was seen in all MN cases. Furthermore, the prominent injuries of glomerular capillaries may be associated with the deterioration of eGFR and the formation of FSGS lesions in MN.

Idiopathic membranous nephropathy: clinical and histologic prognostic features and treatment patterns over time at a tertiary referral center

BACKGROUND

Idiopathic membranous nephropathy (i-MN) is a leading cause of nephrotic syndrome in adults and results in end-stage renal disease in approximately one third of patients. There are few large, long-term US studies evaluating clinical and histologic prognostic factors in i-MN.

METHODS

We describe 132 patients with biopsy-proven i-MN who were followed for a mean period of 68 months at our tertiary referral center from 1977 to 2009, and we analyzed clinical and histologic features that predicted renal outcomes.

RESULTS

The presence of hypertension and treating physician's decision to institute immunosuppression were negative predictors of attaining complete or partial remission. Among clinical variables, impaired renal function (eGFR <60 ml/min/1.73 m(2)) at time of presentation was the only variable at presentation associated with an increased risk of reaching end-stage renal disease. The use of statins and RAAS blockers were protective. The choice of corticosteroids as the initial immunosuppressive agent by referring physicians decreased over time but even in the most recent era (2000-2008) was significant (33%).

CONCLUSION

Renal function at presentation and non-white race were the main predictors of a worse renal outcome. Corticosteroid therapy is still being adopted as first-line therapy in a significant number of patients in this era. The development of guidelines may help clarify the treatment strategies of i-MN.

Glomerular pathology in autosomal dominant MYH9 spectrum disorders: what are the clues telling us about disease mechanism?

Genetic variation in MYH9, encoding non-muscle heavy chain IIA, has been recognized for over a decade as the cause of an autosomal dominant syndrome characterized by macrothrombocytopenia, neutrophil inclusions, and glomerular pathology. More recently, genetic variation in the MYH9 region on chromosome 22 has been associated with chronic kidney disease in African-descent individuals. A better understanding of the disease mechanisms responsible for glomerular injury in autosomal dominant MYH9 syndromes will lead to fuller appreciation of the role of this gene in glomerular biology.