Unusual post-transplantation recurrence of focal segmental glomerulosclerosis which resolved with cyclosporine but not with sirolimus

Management of recurrent focal segmental glomerulosclerosis (FSGS) post renal transplantation

BACKGROUND

One of the common GN causing ESKD is focal segmental glomerulosclerosis (FSGS). Recurrence of FSGS post-transplantation can lead to graft loss. Data on management either prophylactically or once recurrence occurs are limited. This review article aims to assess the effective management of patients with FSGS recurrence post-transplantation, looking mainly at recurrence post prophylactic treatment and remission in case of treatment post recurrence.

METHODS

Twenty-three studies were included using the search MeSH terms "FSGS" "recurrence" "adults" "transplantation" "treatment". Search engines used were Pubmed, clinical key, Scopus and Cochrane library. Inclusion criteria were articles covered adult patients with recurrent FSGS post renal transplantation, treatment with rituximab and plasmapheresis, and articles published from 2000 tt2021. Excluded articles were paediatric population, studies with no reported outcomes of the treatment of FSGS, and Patients who received stem cell transplantation or galactose therapy.

RESULTS

Prophylactic PP did not show a reduction in recurrence of FSGS in 2/3 studies. Prophylactic rituximab was shown to reduce recurrence of FSGS in one-study and case reports. Treatment of recurrent FSGS with PP showed responses ranging from 41% to 100%. Only one study did not show improvement with PP use as treatment having a 27% remission. Treatment with rituximab showed variable results, with reports showing remission ranging from 57% to 100%. Whereas other reports showing no response at all. PP prescription reporting was variable. One study suggested intensified PP regimen while in most other studies PP was guided by the response reflected by the reduction of proteinuria.

DISCUSSION

Reviewing the treatment of recurrent FSGS is crucial, as there no consensus on treating FSGS as the disease is not very common in the adult population. The evidence of different modalities is based on small cohort studies. This paper supports the use of PP and RTX as treatment of recurrent FSGS.

CONCLUSIONS

In conclusion, PP and RTX are the main modalities to treat recurrent FSGS with varying response rates. Prophylactic PP does not play a role in preventing recurrent FSGS. Prophylactic rituximab might play a role in preventing FSGS post-transplantation. PP and RTX, when used as a treatment, show variable response rates. Larger RCTs are needed to have a strong level of evidence to base our clinical management on.

A critical re-analysis of cases of post-transplantation recurrence in genetic nephrotic syndrome

BACKGROUND

Genetic defects in podocyte proteins account for up to 30% of steroid-resistant nephrotic syndrome (SRNS) in the paediatric population. Most children with genetic SRNS are resistant to immunosuppression and at high risk of progression to stage 5 chronic kidney disease. Kidney transplantation is often the treatment of choice. The possibility of post-transplantation disease recurrence in genetic SRNS remains controversial, and poses fundamental questions about disease biology.

METHODS

We critically evaluated the published cases of post-transplantation recurrence in genetic patients, particularly testing 'mutations' against the most recent population variant databases, in order to clarify the diagnoses, and compare the clinical courses and responses to therapy.

RESULTS

Biallelic pathogenic variants in NPHS1 leading to a complete absence of nephrin were the most commonly reported and best understood instance of nephrotic syndrome occurring post-transplantation. This is an immune-mediated process driven by antibody production against the novel nephrin protein in the allograft. We also identified a number of plausible reported cases of post-transplantation recurrence involving pathogenic variants in NPHS2 (8 patients, biallelic), one in WT1 (monoallelic) and one in NUP93 (biallelic). However, the mechanism for recurrence in these cases remains unclear. Other instances of recurrence in genetic disease were difficult to interpret due to differing clinical criteria, inclusion of patients without true pathogenic variants or the influence of other factors on renal outcome.

CONCLUSIONS

Overall, post-transplantation recurrence remains very rare in patients with genetic SRNS. It appears to occur later after transplantation than in other patients and usually responds well to plasmapheresis with a good renal outcome.

Early treatment with everolimus exerts nephroprotective effect in rats with adriamycin-induced nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) is a clinical state characterized by massive proteinuria and excessive fluid retention. The effects of early versus late treatment with low or high doses of oral everolimus, a mammalian target of rapamycin inhibitor, on proteinuria in NS have not been previously described.

METHODS

The effects of early treatment (2 days prior to NS induction) versus late treatment (beginning 2 weeks following the establishment of NS) with a low (20 mg/L) or high (100 mg/L) dose of everolimus for 5-7 weeks on proteinuria and nephrin/podocin abundance were assessed in male adult SD rats with adriamycin-induced NS.

RESULTS

Adriamycin caused a significant increase in daily and cumulative proteinuria throughout the experimental period. Early, and to a lesser extent late treatment, with a low dose of everolimus, significantly decreased both daily and cumulative proteinuria and improved renal function. The anti-proteinuric effects of low-dose everolimus were associated with restoration of the disruptive glomerular nephrin/podocin abundance. In contrast, administration of a high dose of everolimus resulted in a decrease in proteinuria in NS rats, subsequently to deterioration of renal function.

CONCLUSIONS

Early, and to a lesser extent late treatment, with a low but not a high dose of everolimus is effective in reducing proteinuria in nephrotic rats. The mechanism may be via nephrin/podocin protection.

Recurrence of focal segmental glomerulosclerosis in renal allograft: an in-depth review

Focal segmental glomerulosclerosis is a major cause of chronic kidney disease requiring transplantation in children. Recurrence rate in the renal allograft transplantation is as high as 50%. Recurrence of FSGS is associated with renal dysfunction and early graft loss. To date, there is no established therapy for recurrent FSGS after renal transplant. We have reviewed the current English literature in order to summarize current practices with emphasis on graft outcome. We conclude that despite multiple approaches to the post transplant management of recurrent FSGS, none have been shown to be consistently beneficial. Currently, pheresis combined with high dose anti-calcineurin with or without rituximab seems to be the most promising. Further controlled studies are needed to define the optimal therapeutic regimens to treat recurrent of FSGS.

Sirolimus interacts with pathways essential for podocyte integrity

BACKGROUND

The specific mTor inhibitor sirolimus has been implicated in the pathogenesis of renal glomerular lesions and nephrotic syndrome appearance after transplantation. Podocyte injury and focal segmental glomerulosclerosis have been related to sirolimus therapy in some patients but the pathways underlying these lesions remain hypothetical.

METHODS

To go further in the comprehension of these mechanisms, primary cultures of human podocytes were exposed to therapeutic-range concentrations of sirolimus.

RESULTS

Cell viability was not affected after 2 days' exposure to the drug but changes in cell phenotype and cytoskeleton reorganization were observed. We also evidenced that vascular endothelial growth factor (VEGF) synthesis and Akt phosphorylation were decreased by sirolimus addition. We did not observe any loss of podocyte differentiation markers with the notable exception of WT1, a transcription factor essential for maintaining podocyte integrity. WT1 gene and protein expression in podocytes were decreased in a dose-dependent manner after incubation with sirolimus.

CONCLUSION

Taken together, these data suggest that sirolimus could impair pathways essential for podocyte integrity and therefore predisposes to glomerular injury.

[Proteinuria and renal transplantation]

The occurrence of proteinuria in transplant patients is a marker of poor prognosis. The augmentation of proteinuria is associated with an increased risk of patient death and graft loss. Even a low-level urinary protein excretion (0.5 g/d) has a highly significant negative impact on graft survival whether it is observed 1 or 3 months after transplantation. Urinary albumin excretion rate has also a major effect on risks of graft loss and death with functional kidney, macro-albuminuria increasing the risks of respectively 16.4 and 4.12 times comparatively to micro-albuminuria, which itself multiplies the risks by 14.2 and 5.5 respectively, compared to normo-albuminuria. In terms of factors causing proteinuria apparition, the role of proliferation signal inhibitors has been recently observed. Sirolimus, especially at high dose, in particular can induce the occurrence of proteinuria, which is reversible with treatment discontinuation, but only with a partial recovery of the renal function. Proteinuria may be explained by a direct glomerular impact of sirolimus on several podocyte markers.

mToR inhibitors-induced proteinuria: mechanisms, significance, and management

Massive urinary protein excretion has been observed after conversion from calcineurin inhibitors to mammalian target of rapamycin (mToR) inhibitors, especially sirolimus, in renal transplant recipients with chronic allograft nephropathy. Because proteinuria is a major predictive factor of poor transplantation outcome, many studies focused on this adverse event during the past years. Whether proteinuria was due to sirolimus or only a consequence of calcineurin inhibitors withdrawal remained unsolved until high range proteinuria has been observed during sirolimus therapy in islet transplantation and in patients who received sirolimus de novo. Podocyte injury and focal segmental glomerulosclerosis have been related to mToR inhibition in some patients, but the pathways underlying these lesions remain hypothetic. We discuss herein the possible mechanisms and the significance of mToR blockade-induced proteinuria.

Abrogation of nephrotic proteinuria by rituximab treatment in a renal transplant patient with relapsed focal segmental glomerulosclerosis

Relapse of focal segmental glomerulosclerosis (FSGS) after renal transplantation is 20-40%. Recurrence after a first relapse is 80%. The only current treatment is plasmapheresis and/or cyclophosphamide. We report successful treatment of a second relapse in a 48-year-old patient. At age 33, FSGS was diagnosed. The patient began hemodialysis 1 year later. In her first renal transplant, she developed recurrent FSGS and reached terminal transplant failure 3 years later. Eight years later, a second transplant was performed. Immunosuppressive regimen: steroids, mycophenolate mofetil (MMF), tacrolimus (TAC), and rabbit anti-thymocyte globulin. Proteinuria of 2-6 g/day was detected and a biopsy showed recurrent FSGS. Plasmapheresis was started without success. Another biopsy still showed FSGS. The patient received two doses of rituximab (375 mg/m2 each) i.v. Three weeks later, proteinuria was 350 mg/day (serum-creatinine 1.6 mg/dl). Twelve months later, proteinuria was at 90 mg/day. Rituximab might be an option for recurrent FSGS after renal transplantation.

High sirolimus levels may induce focal segmental glomerulosclerosis de novo

Sirolimus has been associated with high-range proteinuria when used in replacement of calcineurin inhibitors in renal transplant recipients with chronic allograft nephropathy (CAN). Primary FSGS was demonstrated previously in some such patients, but the coexistence of CAN lesions made the interpretation uneasy. However, nephrotic syndrome and FSGS were observed recently in three patients who received sirolimus de novo, without medical history of primary FSGS or CAN. Markers of podocyte differentiation were studied in kidney biopsies of the three patients who received sirolimus de novo and of five patients who switched to sirolimus. All patients developed FSGS lesions of classic type (not otherwise specified), but only switched patients exhibited advanced sclerotic lesions. Immunohistochemistry showed that some podocytes in FSGS lesions had absent or diminished expression of the podocyte-specific epitopes synaptopodin and p57, reflecting dedifferentiation, and had acquired expression of cytokeratin and PAX2, reflecting a immature fetal phenotype. Such a pattern of epitope expression provides evidence for podocyte dysregulation. Moreover, a decrease in vascular endothelial growth factor expression was observed in some glomeruli. In conclusion, sirolimus induces FSGS that is responsible for proteinuria in some transplant patients.

Recurrence of proteinuria 10 years post-transplant in NPHS2-associated focal segmental glomerulosclerosis after conversion from cyclosporin A to sirolimus

Mutations in the NPHS2 gene, which encodes podocin, are associated with steroid-resistant nephrotic syndrome in childhood. Renal histology frequently presents focal segmental glomerulosclerosis (FSGS). Post-transplant recurrence of proteinuria in patients affected by homozygous or compound heterozygous NPHS2 mutation is encountered rarely (1-2%) compared to 30% recurrence in nonhereditary FSGS. We report on a pediatric kidney transplant recipient with NPHS2-associated nephrotic syndrome and FSGS, who developed biopsy-proven recurrence of FSGS 10 years post-transplant in temporal association with conversion from cyclosporin A (CsA)- to sirolimus (SRL)-based immunosuppression, due to histological evidence of severe CsA-induced nephrotoxicity. Reswitch of the immunosuppressive regimen from SRL to CsA led to a noticeable decrease of proteinuria and to stabilization of graft function. We conclude that patients with hereditary FSGS are not entirely protected from post-transplant recurrence of proteinuria, even in the long term. The close temporal relationship of FSGS recurrence with CsA withdrawal and conversion to SRL suggests that caution should be exercised in the use of CsA-free immunosuppression also in patients with NPHS2-associated FSGS.

Resolution of sirolimus-induced pneumonitis after conversion to everolimus

BACKGROUND

Sirolimus-induced pneumonitis usually requires the complete cessation of sirolimus. Herein we have reported five cases of recovery from sirolimus pneumonitis after conversion from sirolimus to everolimus.

PATIENTS

All five cases were comparable with regard to their clinical conditions. The ages were between 46 and 64 years. They had received kidney transplants 3 to 18 years earlier. In four cases, the reason for sirolimus therapy was toxicity due to calcineurin inhibitors on a transplant biopsy; three of the patients also displayed malignant tumors: renal cell carcinoma, spinocellular carcinoma, or melanoma. Their serum creatinine levels were elevated between 150 and 350 micromol/L. In all five cases, bronchoscopy disclosed lymphocytic pneumonitis and bronchiolitis obliterans. The immunosuppressive co-medications were prednisolone in three, azathioprine in one, and mycophenolate mofetil in four cases. The previous sirolimus dose was 1 to 4 mg/day, with sirolimus trough levels between 5 and 12 ng/mL. The patients were switched to everolimus at doses between 1 x 0.25 and 2 x 0.75 mg/day to achieve trough concentrations between 3 and 8 ng/mL. Pulmonary symptoms and radiological findings resolved completely within 1 to 4 weeks.

CONCLUSION

Everolimus is more hydrophilic by virtue of differing from sirolimus by one hydroxyl group. Sirolimus-induced pneumonitis improved after conversion to everolimus.

Sirolimus-Associated Proteinuria and Renal Dysfunction

Sirolimus is a novel immunosuppressant with potent antiproliferative actions through its ability to inhibit the raptor-containing mammalian target of rapamycin protein kinase. Sirolimus represents a major therapeutic advance in the prevention of acute renal allograft rejection and chronic allograft nephropathy. Its role in the therapy of glomerulonephritis, autoimmunity, cystic renal diseases and renal cancer is under investigation. Because sirolimus does not share the vasomotor renal adverse effects exhibited by calcineurin inhibitors, it has been designated a 'non-nephrotoxic drug'. However, clinical reports suggest that, under some circumstances, sirolimus is associated with proteinuria and acute renal dysfunction. A common risk factor appears to be presence of pre-existing chronic renal damage. The mechanisms of sirolimus-associated proteinuria are multifactorial and may be due to an increase in glomerular capillary pressure following calcineurin inhibitor withdrawal. It has also been suggested that sirolimus directly causes increased glomerular permeability/injury, but evidence for this mechanism is currently inconclusive. The acute renal dysfunction associated with sirolimus (such as in delayed graft function) may be due to suppression of compensatory renal cell proliferation and survival/repair processes. Although these adverse effects occur in some patients, their occurrence could be minimised by knowledge of the molecular effects of sirolimus on the kidney, the use of sirolimus in appropriate patient populations, close monitoring of proteinuria and renal function, use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers if proteinuria occurs and withdrawal if needed. Further long-term analysis of renal allograft studies using sirolimus as de novo immunosuppression along with clinical and laboratory studies will refine these issues in the future.