Early Focal Segmental Glomerulosclerosis Research Articles

Role of detached podocytes in differentiating between minimal change disease and early focal segmental glomerulosclerosis, can we rely on routine light microscopy?

BackgroundDetachment of podocytes represents a turning point in the development of glomerular sclerosis and consequently, of CKD progression. Furthermore, detachment may differentiate minimal change disease (MCD) cases—which have only podocyte effacement—from early focal segmental glomerulosclerosis (FSGS) in which effacement and detachment are observed by electron microscopy. Noteworthy, it is not uncommon for early FSGS to present with clinical presentation and light microscopy (LM) pictures identical to MCD. In our routine practice, we often find cells that lie freely in Bowman’s space by LM. In this study, we try to determine whether these cells are detached podocytes that are worth reporting or just an artifact that can be ignored.MethodsTo the best of our knowledge, no study has discussed the accuracy of LM in detecting detached podocytes by the routinely used stains. We retrospectively selected 118 cases that were diagnosed as MCD by LM, and searched for detached cells in Bowman’s space in their archived, routinely stained LM slides. After that, we tried to find any correlation between the clinical course, detached cells in LM picture and the EM reports. ResultsLM can significantly detect detached podocytes with a positive predictive value of 93%, specificity of 85%, and sensitivity of 46%. Significant correlations were found between detached cells and degree of proteinuria and late steroid resistance.Conclusion Detecting detached podocytes by LM is a specific finding that must be reported whenever detected, as it predicts response to steroids and may be able to differentiate MCD from early FSGS by identifying patients who could have podocytopenia.

The combined use of Adrenocorticotropic hormone (ACTH) and Calcineurin inhibitor (CNI) in the treatment of Refractory Nephrotic Syndrome in a child

Background: Primary podocytopathies including Focal Segmental Glomerulosclerosis (FSGS) have been recognized to show variable responses to conventional treatment and overall prognosis. Persistent failure to respond to therapies remains a vexing problem for clinicians. ACTH has recently resurged as a therapy for treatment-resistant podocytopathies. We describe a case of steroid-resistant NS in a 10-year-old boy with a history of multiple failed secondary therapies, who showed partial response to biweekly ACTH therapy. Further clinical improvement was observed with the addition of the calcineurin inhibitor (CNI), tacrolimus. Case description: A 10-year-old Hispanic boy, diagnosed with frequently-relapsing steroid sensitive NS at the age of 2, and was largely relapse-free for 5 years on Cyclosporine A (CsA). Within two months after a trial off CsA, he relapsed. His course was complicated by more frequent relapses and steroid resistance. Renal biopsy performed at this time showed early focal segmental glomerulosclerosis (FSGS) and no signs of CsA-induced nephropathy. Whole exome sequencing revealed a heterozygous variant of uncertain significance in PLCE1 (Phospholipase C Epsilon 1). Trials of the steroid sparing agents tacrolimus and mycophenolate mofetil, both with and without steroids, were ineffective. He had several prolonged hospitalizations due to poorly controlled relapse. He became dependent on biweekly 25% albumin infusions. His renal function deteriorated from a baseline creatinine of 0.3 mg/dl to 0.7 mg/dl due to multiple episodes of acute kidney injury. ACTH initiated at a low dose of 40 units/1.73 m² biweekly was ineffective. Three months later, the dose was increased to 80 units/1.73 m² biweekly and he achieved partial remission and renal function returned to baseline. Tacrolimus was added at 6 months for synergy with trough levels maintained between 3-5 ng/ml. He achieved partial remission, and avoided further hospitalizations. Conclusion: ACTH alone or in combination with calcineurin inhibitor (CNI) can be a viable alternative for children who are resistant to other therapies. Variability in renal phenotype has been implicated with the PLCE1 (Phospholipase C Epsilon 1) gene. In this case, we suspect the role of his heterozygous variant PLCE1 mutation, or likely a compound heterozygous state with another unidentified mutation or modifiers or environmental factors, plays a role in the progression to a refractory NS state.

Inhibition of mTOR delayed but could not prevent experimental collapsing focal segmental glomerulosclerosis

Anti-Thy1.1 transgenic mice develop glomerular lesions that mimic collapsing focal segmental glomerulosclerosis (FSGS) in humans with collapse of the glomerular tuft and marked hyperplasia of the parietal epithelial cells (PECs). Immunostaining of phosphor-S6 ribosomal protein (pS6RP) revealed high mTOR activity in PECs of the FSGS lesions of these mice. In this study we questioned whether the mTOR inhibitor rapamycin (sirolimus) could attenuate the development and progression of glomerulosclerotic lesions in the anti-Thy1.1 transgenic mice. We observed reduced mTOR signalling and proliferation in human parietal epithelial cells after rapamycin treatment. Experiments with anti-Thy1.1. mice showed that early treatment with sirolimus reduced the development of glomerular lesions and glomerular cell proliferation at day 4. Levels of albuminuria, podocyte injury and podocyte number were similar in the sirolimus and vehicle treated groups. The initial beneficial effects of sirolimus treatment were not observed at day 7. Late sirolimus treatment did not reduce albuminuria or the progression of glomerulosclerosis. Taken together, rapamycin attenuated PEC proliferation and the formation of early FSGS lesions in experimental FSGS and reduced human PEC proliferation in vitro. However, the initial inhibition of PEC proliferation did not translate into a decline of albuminuria nor in a sustained reduction in sclerotic lesions.

Potential role of Claudin-1 immunohistochemical expression and ultrastructural changes in detecting early focal segmental glomerulosclerosis

Background: Focal segmental glomerulosclerosis (FSGS) and Minimal change disease (MCD) are two disease entities presented mainly by nephrotic syndrome. While 95% of MCD cases showed complete remission on steroid therapy, 50% of FSGS cases progress to end stage renal disease. Early sclerotic lesions in FSGS can be missed in routine H&E examination. Objective: To differentiate early FSGS from MCD by detection of activated parietal epithelial cells (PECs) in early glomerular sclerotic lesions using Claudin-1 immunohistochemical (IHC) staining and by examining podocyte ultrastructural changes. Materials and Methods: This retrospective study included 28 cases diagnosed as MCD and 20 cases diagnosed as early FSGS. Clinicopathologic data collection, claudin-1 IHC staining and reviewing ultrastructural changes were performed and the results were statistically analyzed. Results: A statistically significant correlation was detected between claudin-1 expression and the initial diagnosis of the studied groups (P=0.005). Claudin-1 was expressed in a visceral location in (39.28%) of the biopsies initially diagnosed as MCD thus were reevaluated as early FSGS lesions. 63.64% of these positive cases were presented by steroid resistant nephrotic syndrome and 63.6% of which showed some ultrastructural changes of FSGS in podocytes including abnormalities in mitochondrial shapes, endoplasmic reticulum changes and a decreased number of autophagic vacuoles. Conclusion: Claudin-1 is a novel diagnostic marker that can differentiate between confusing cases of early FSGS versus MCD. Defective autophagy plays a role in the pathogenesis of FSGS.

Early Focal Segmental Glomerulosclerosis as a Cause of Delayed Graft Function With Combined Acute Antibody Rejection: A Case Report

Focal segmental glomerulosclerosis (FSGS) is the most common form of post-transplant glomerulonephritis. We describe a case where a biopsy proved that early recurrence of FSGS on postoperative day 1 was the cause of delayed graft function. A 39-year-old man, on hemodialysis for 15 years due to polycystic kidney disease, received a cadaveric renal transplantation. On postoperative day 1, his hourly urine output decreased from 700–800 mL to 50 mL. The graft biopsy showed a mild acute kidney injury confusing nephrotic syndrome. On postoperative day 45, his creatinine level increased to 3.02 mg/dL with severe proteinuria. A kidney biopsy showed focal segmental glomerulosclerosis. On postoperative day 120, his creatinine level elevated again, concomitant with proteinuria. A kidney biopsy showed FSGS with antibody-mediated rejection. After plasmapheresis, his creatinine level decreased to 1.3 mg/dL with mild proteinuria. Once active in the allograft, de novo FSGS is a potentially aggressive process. In this case, it could be managed because of an accurate diagnosis and appropriate treatment.

Treatment by immunoadsorption for recurrent focal segmental glomerulosclerosis after paediatric kidney transplantation: a multicentre French cohort.

Primary focal segmental glomerulosclerosis (FSGS) frequently recurs after kidney transplantation (KTx) in children. This can lead to delayed graft loss. As the management of children with recurrent FSGS is not well established, apheresis strategies could be a cornerstone to control the disease. Immunoadsorption (IA) is a recent apheresis therapy. There have been few studies examining IA in this setting. We report the results of IA for management of recurrent FSGS after KTx in children in France. We included all children treated with IA for early FSGS recurrence after KTx between January 2011 and June 2014 in France. We excluded genetic forms of FSGS. Patients' characteristics and technical data on IA were retrospectively collected. Recurrence was defined as nephrotic proteinuria during the post-transplantation period. Partial and complete remissions were defined when urine protein:creatinine ratios were less than 0.2 and 0.05 g/mmol, respectively. Twelve patients, from six paediatric KTx units, presenting with FSGS recurrence between 0 and 21 days after KTx were treated with IA. Ten of 12 children were responders: 2 achieved partial remission and 8 complete remission. The decrease of proteinuria rapidly occurred within the first 10 sessions after initiating IA. After 3 months of IA, two patients maintained remission without IA and eight became IA dependent. No severe side effects were reported. Our study reports on the efficacy of IA in the recurrence of FSGS after KTx in children. Further prospective controlled studies are required to confirm these results and to optimize the management of FSGS recurrence after paediatric KTx.

An unusual case of focal segmental glomerulosclerosis presenting with retropharyngeal edema

IntroductionAcute neck swelling with pharyngeal signs often triggers emergency consultation. Treatment and diagnosis are usually multidisciplinary. Failing to find a possible etiology may lead to misdiagnosis. Case presentationA young man presented to the emergency room with a 4-day history of cough, neck swelling and sore throat. Laboratory testing showed a leukocyte count of 9200 without left shift. Mild elevated CRP with 1.7 was noted and computed tomography (CT) showed fluid accumulation in the retropharyngeal space and neck edema down to thyroid region. Antibiotic was prescribed and admitted to infection ward under the impression of deep neck infection. During hospitalization, needle aspiration was performed where water fluid was collected without pus. Investigations showed massive proteinuria, hypoalbuminemia and hypercholesterolemia. The early focal segmental glomerulosclerosis was found by renal biopsy. After prednisolone 60mg daily and albumin supplement, the neck swelling, swallowing pain and general edema had completely resolved. DiscussionThe purpose of this case is to raise awareness of nephrotic syndrome as an unusual but possibly cause of retropharyngeal edema. We highlight the diagnostic features that will allow the physicians to make the correct diagnosis, avoid unnecessary incision and drainage, and commence effective treatment early in the disease course.

The significance of tubuloreticular inclusions as a marker of systemic stimulation by interferons in a case of focal and segmental glomerulosclerosis associated with cytomegalovirus (CMV) infection.

The identification of large numbers of tubuloreticular inclusions (TRIs) in renal biopsies may be useful to raise diagnostic suspicion for certain clinical entities, particularly autoimmune diseases and viral infections. We report a case of a 65-year-old female with a 2-week history of malaise, massive proteinuria and lower extremity edema of acute onset. A renal biopsy was performed and the diagnosis of non-human immunodeficiency virus (HIV) tip-located, early focal segmental glomerulosclerosis (FSGS) was established. The electron microscopy examination was remarkable for the presence of diffuse foot process effacement and frequent TRIs in the endothelial cells of the glomerular capillary loops, endothelium of arterioles and cytoplasm of fibroblasts in the interstitium, highly suggestive of an underlying etiology. Patient clinical and laboratory workup revealed the absence of an autoimmune disease but the presence of a subclinical cytomegalovirus (CMV) infection. Therefore, we highlight that the identification of TRIs is a useful indicator of systemic interferon activity. In the present case, the unusual location of numerous TRIs was associated with a subclinical CMV infection in an immunocompetent patient.

Early Focal Segmental Glomerulosclerosis as a Cause of Renal Allograft Primary Nonfunction

Background. Primary focal segmental glomerulosclerosis (FSGS) is one of the commonest causes of glomerular disease and if left untreated will often progress to established renal failure. In many cases the best treatment option is renal transplantation; however primary FSGS may rapidly recur in renal allografts and may contribute to delayed graft function. We present a case of primary nonfunction in a renal allograft due to biopsy-proven FSGS. Case Report. A 32-year-old man presented with serum albumin of 22 g/L, proteinuria quantified at 12 g/L, and marked peripheral oedema. Renal biopsy demonstrated tip-variant FSGS. Despite treatment, the patient developed progressive renal dysfunction and was commenced on haemodialysis. Cadaveric renal transplantation was undertaken; however this was complicated by primary nonfunction. Renal biopsies failed to demonstrate evidence of acute rejection but did demonstrate clear evidence of FSGS. The patient was treated to no avail. Discussion. Primary renal allograft nonfunction following transplantation is often due to acute kidney injury or acute rejection. Recurrent FSGS is recognised as a phenomenon that drives allograft dysfunction but is not traditionally associated with primary nonfunction. This case highlights FSGS as a potentially aggressive process that, once active in the allograft, may prove refractory to targeted treatment. Preemptive therapies in patients deemed to be at high risk of recurrent disease may be appropriate and should be considered.

Blood Pressure in Minimal Change and Other Types of Nephrotic Syndrome

Blood pressure was evaluated in adult patients (n = 9) and children (n = 57) with nephrotic syndrome and minimal change glomerulonephritis (GN). Prior to steroid treatment in the edematous phase, hypertension was found in 78% of adults (BP greater than or equal to 140/90 mm Hg or antihypertensive treatment other than diuretics) and 95% of children (BP greater than 95 percentile of age). After complete remission, the prevalence of hypertension decreased to 33% in adults and 19% in children. In 21 children with early focal segmental glomerulosclerosis, the prevalence of hypertension (BP greater than 95th percentile) was 91% and 24% after complete remission. In 20 adult patients with membranous GN, the prevalence of hypertension in the edematous phase was 89% and 30% after complete or partial remission. It is concluded that, irrespective of age, hypertension is a common feature of the nephrotic syndrome unrelated to steroid therapy or renal failure.