Melanocortin 1 receptor agonists reduce proteinuria

Updates on C3 Glomerulopathy in Kidney Transplantation: Pathogenesis and Treatment Options

C3 glomerulopathy is a rare disease, characterized by an abnormal activation of the complement's alternative pathway that leads to the accumulation of the C3 component in the kidney. The disease recurs in more than half of kidney transplant recipients, with a significant impact on graft survival. Recurrence of the primary disease represents the second cause of graft loss after organ rejection. In C3 glomerulopathy, there are several risk factors which can promote a recurrence during transplantation, such as delayed graft function, infection and monoclonal gammopathy. All these events can trigger the alternative complement pathway. In this review, we summarize the impact of C3 glomerulopathy on kidney grafts and present the latest treatment options. The most widely used treatments for the disease include corticosteroids and mycophenolate mofetil, which are already used chronically by kidney transplant recipients; thus, additional treatments for C3 glomerulopathy are required. Currently, several studies using anti-complement drugs (i.e., eculizumab, Ravalizumab, avacopan) for C3 glomerulopathy in kidney transplant patients are ongoing with encouraging results.

Enhanced Biohomogeneous Composite Membrane-Encapsulated Nanoplatform with Podocyte Targeting for Precise and Safe Treatment of Diabetic Nephropathy

Diabetic nephropathy (DN), associated with high mobility and disability, is the leading cause of end-stage kidney disease worldwide. Dysfunction of the mammalian target of the rapamycin (mTOR) pathway and reactive oxygen species (ROS) activation in the glomeruli is the main hypnosis for DN progression. However, the use of mTOR inhibitors for DN treatment remains controversial. In this study, we built a multifunctional selective mechanistic target of rapamycin complex 1 (mTORC1) inhibiting nanoplatform (naming as ESC-HCM-B) that targets the release of mTOR and ROS inhibitors near podocytes, aiming to confirm whether combination therapy is an alternative method for DN treatment. The results showed that ESC-HCM-B achieved high drug loading because of the core mesoporous silica nanoparticles (MSNPs), and the enhanced biohomogeneous composite membrane endowed ESC-HCM-B with the characteristics of avoiding immune phagocytosis, automatic valve-type slow-release drug, and high stability. In vitro, the nanoplatform showed high efficiency in podocyte targeting but no significant cytotoxicity or apoptotic promotion. In particular, the quantum dots carried by ESC-HCM-B further amplified the effect of "nanoenzyme"; this mechanism reduced the ROS level in podocytes induced by high glucose, protected mitochondrial damage, and restored mitochondrial energy metabolism. In vivo, the nanoplatform specifically targeted the glomerular and podocyte regions of the kidney. After treatment, the nanoplatform significantly reduced urinary protein levels and delayed glomerulosclerosis in DN rats. This nanoplatform provides a safe and effective strategy for DN treatment.

Negative Modulation of B Cell Activation by Melanocortin 1 Receptor Signaling Protects against Membranous Nephropathy

SIGNIFICANCE STATEMENT

Emerging evidence suggests that melanocortin neuropeptides-specifically adrenocorticotropic hormone-offer a novel, steroidogenic-independent therapeutic modality for membranous nephropathy (MN). The molecular mechanism underlying this beneficial effect, however, remains largely elusive. To investigate whether melanocortins modulate humoral immunity, the authors induced passive Heymann nephritis, a model of human MN, in wild-type and melanocortin 1 receptor (MC1R) knockout rats and treated them with melanocortin agents. Additional rats received adoptive transfer of bone marrow-derived cells beforehand from wild-type or MC1R knockout rats. The findings indicate that MC1R signaling plays a key role in negative modulation of B-cell activation and thereby suppresses humoral immune responses in passive Heymann nephritis, and suggest that MC1R signaling might offer a novel B cell-targeted therapeutic strategy for MN.

BACKGROUND

Emerging evidence suggests that the pituitary neuropeptide melanocortins-specifically, adrenocorticotropic hormone-offer a novel nonsteroidogenic therapeutic modality for membranous nephropathy (MN). However, the mechanism(s) of action remains elusive.

METHODS

To investigate whether melanocortins modulate humoral immunity, we induced passive Heymann nephritis (PHN), a model of MN, in wild-type (WT) and melanocortin 1 receptor (MC1R) knockout (KO) rats. We treated the animals with melanocortin agents-repository corticotropin injection, the nonsteroidogenic pan-melanocortin receptor agonist [Nle 4 , DPhe 7 ]-α-melanocyte stimulating hormone, the selective MC1R agonist MS05, vehicle gel, or phosphate-buffered saline-and evaluated kidney function, histology, and molecular changes. Additional rats received adoptive transfer of syngeneic bone marrow-derived cells beforehand from WT or MC1R KO rats.

RESULTS

KO of MC1R worsened PHN and this was associated with increased deposition of autologous immunoglobulin G (IgG) and complement C5b-9 in glomeruli and higher circulating levels of autologous IgG-evidence of a sensitized humoral immune response. Melanocortin therapy ameliorated PHN in WT rats, coinciding with reduced glomerular deposition of autologous IgG and C5b -9. The beneficial efficacy of melanocortins was blunted in KO rats but restored by adoptive transfer of syngeneic bone marrow-derived cells derived from WT rats. Mechanistically, MC1R was expressed in B lymphocytes and was negatively associated with B cell activation. MC1R agonism triggered the expression of microphthalmia-associated transcription factor in activated B cells in a cAMP-dependent mode and also repressed the expression of interferon regulatory factor 4 (a lymphoid transcription factor essential for B-cell development and maturation), resulting in suppressed plasma cell differentiation and IgG production.

CONCLUSIONS

MC1R signaling negatively modulates B cell activation and suppresses humoral immune responses in PHN, suggesting that MC1R signaling might offer a novel therapeutic target for MN.

Hematopoietic-specific melanocortin 1 receptor signaling protects against nephrotoxic serum nephritis and mediates the beneficial effect of melanocortin therapy

The melanocortin hormone system has emerged as a novel therapeutic target for treating refractory glomerular diseases. However, the role of hematopoietic melanocortin 1 receptor (MC1R) signaling remains unknown. Upon insult by rabbit nephrotoxic serum, MC1R null-mutant mice developed more severe crescentic glomerulonephritis than wild-type mice, marked by aggravated proteinuria, kidney dysfunction and histologic lesions. Melanocortin therapy, using Repository Corticotropin Injection (Acthar Gel), the pan-melanocortin receptor agonist NDP-MSH, or the MC1R agonist MS05, ameliorated experimental nephritis in wild-type mice but this effect was blunted in null mice. Exacerbated experimental nephritis in null mice was associated with increased glomerular deposition of autologous IgG and C5b-9, in parallel with higher circulating levels of autologous IgG2c and IgG3. Additionally, the Th1 immune response was potentiated in null mice with experimental nephritis, accompanied by diminished kidney FoxP3+ regulatory T cells. Kidney infiltration of macrophages was also augmented by MC1R deficiency with an enhanced M1 polarization. Moreover, adoptive transfer of syngeneic bone marrow-derived cells from wild-type mice mitigated experimental nephritis in null mice and restored the beneficial efficacy of melanocortins. Mechanistically, MC1R was expressed by diverse subsets of kidney leukocytes, including macrophages, T and B lymphocytes, and was inversely associated with the NFκB pathway, a key player in immune responses. MS05 attenuated the production of rabbit IgG-specific IgG2c and IgG3 in cultured wild-type splenocytes, and promoted M2 polarization in M1-primed wild-type macrophages, associated with NFκB inhibition. In contrast, in null splenocytes or macrophages, this effect of MS05 was barely detectable, but was mimicked by an NFκB inhibitor. Thus, hematopoietic MC1R signaling attenuates experimental nephritis and mediates the beneficial effect of melanocortin therapy via, in part, regulating the immune response.

How immunosuppressive drugs may directly target podocytes in glomerular diseases

Podocytes are the direct target of immunologic injury in many immune-mediated glomerular diseases, leading to proteinuria and subsequent kidney failure. Immunosuppressive agents such as steroids, calcineurin inhibitors, and rituximab are the commonly used treatment strategies in this context for their immunotherapeutic or anti-inflammatory properties. However, in recent years, studies have demonstrated that immunosuppressive agents can have a direct effect on podocytes, introducing the concept of the non-immunologic mechanism of kidney protection by immunomodulators. In this review, we focus on the mechanisms by which these agents may directly target the podocyte independent of their systemic effects and examine their clinical significance.

Adrenocorticotropic hormone: An expansion of our current understanding of the treatment for nephrotic syndrome

In clinical practice, we may encounter a treatment dilemma where in some patients with nephrotic syndrome are resistant to glucocorticoids or immunosuppressive agents. Thus, we currently lack viable treatment options and eagerly await the availability of new drugs. Adrenocorticotropic hormone (ACTH) had earlier been used to treat nephrotic syndrome in children, but has now become less popular owing to the advent of oral glucocorticoids. However, in recent studies, ACTH was reportedly used again for treating nephrotic syndrome, reducing proteinuria and protecting renal function, indicating a possibility for its use in the treatment of refractory nephrotic syndrome. This review analysed the validity of ACTH in these studies, focusing on the mechanism of action, application in both paediatric and adult patients with nephrotic syndrome, particularly in children, and possible side effects. We anticipate that our findings will help clinicians in treatment decision-making.

Repository Corticotropin in Treating de novo C3 Glomerulonephritis after Transplantation

Introduction

De novo C3 glomerulonephritis (C3GN) after transplant is uncommon. Although eculizumab has been used successfully in several cases, the response is heterogeneous, and treatment strategies remain undefined. The use of repository corticotropin in C3GN has not been described in the literature.

Case Report

A 48-year-old African American male with kidney transplantation secondary to presumed diabetic nephropathy presented 6 years after transplant with lower extremity edema and nephrotic range proteinuria. His urine protein to creatinine ratio (UPCR) was 8.2 g/g. Renal allograft biopsy confirmed the diagnosis of C3GN. He was treated with eculizumab (Solaris®) 900 mg IV once weekly for 4 weeks and repository corticotropin (H.P. Acthar® gel) 80 units SQ twice weekly for 6 months with a near-complete resolution of proteinuria within 3 months of the treatment. The patient presented again 6 months after completing the therapy with a recurrence of proteinuria, which peaked at 11.6 g/g of UPCR. Repeat kidney allograft biopsy was consistent with C3GN. He was started on repository corticotropin 80 units SQ twice weekly, which resulted in a reduction of proteinuria to >50% within 2 months of therapy. When eculizumab 900 mg IV weekly for 4 weeks was added with repository corticotropin, the proteinuria resolved within 10 weeks of treatment. The patient was maintained on monotherapy of repository corticotropin and has been in complete remission of proteinuria for more than a year until his last follow-up.

Conclusion

This is the first case report describing the role of repository corticotropin as an effective therapy in reducing proteinuria and maintaining patients with C3GN in proteinuria remission.

Melanocortin System in Kidney Homeostasis and Disease: Novel Therapeutic Opportunities

Melanocortin peptides, melanocortin receptors, melanocortin receptor accessory proteins, and endogenous antagonists of melanocortin receptors are the key components constituting the melanocortin hormone system, one of the most complex and important hormonal systems in our body. A plethora of evidence suggests that melanocortins possess a protective activity in a variety of kidney diseases in both rodent models and human patients. In particular, the steroidogenic melanocortin peptide adrenocorticotropic hormone (ACTH), has been shown to exert a beneficial effect in a number of kidney diseases, possibly via a mechanism independent of its steroidogenic activity. In patients with steroid-resistant nephrotic glomerulopathy, ACTH monotherapy is still effective in inducing proteinuria remission. This has inspired research on potential implications of the melanocortin system in glomerular diseases. However, our understanding of the role of the melanocortinergic pathway in kidney disease is very limited, and there are still huge unknowns to be explored. The most controversial among these is the identification of effector cells in the kidney as well as the melanocortin receptors responsible for conveying the renoprotective action. This review article introduces the melanocortin hormone system, summarizes the existing evidence for the expression of melanocortin receptors in the kidney, and evaluates the potential strategy of melanocortin therapy for kidney disease.

IgA Nephropathy: An Interesting Autoimmune Kidney Disease

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. It is a leading cause of chronic kidney disease and progresses to end-stage kidney disease in up to 40% of patients about 20 years after diagnosis. Additionally, IgAN is associated with significant mortality. The diagnosis currently necessitates a kidney biopsy, as no biomarker sufficiently specific and sensitive is available to supplant the procedure. Patients display significant heterogeneity in the epidemiology, clinical manifestations, renal progression, and long-term outcomes across diverse racial and ethnic populations. Recent advances in understanding the underlying pathophysiology of the disease have led to the proposal of a four-hit hypothesis supporting an autoimmune process. To date, there is no disease-specific treatment but, with a better understanding of the disease pathogenesis, new therapeutic approaches are currently being tested in clinical trials. In this review, we examine the multiple facets and most recent advances of this interesting disease.

Visualized podocyte-targeting and focused ultrasound responsive glucocorticoid nano-delivery system against immune-associated nephropathy without glucocorticoid side effect

Glucocorticoids are widely used in the treatment of nephritis, however, its dose-dependent side effects, such as the increased risk of infection and metabolic disturbances, hamper its clinical use. This study reports a visualized podocyte-targeting and focused ultrasound responsive glucocorticoid nano-delivery system (named as Dex/PFP@LIPs-BMS-α), which specific delivers dexamethasone (Dex) to podocyte targets and reduces systemic side effects.

Methods: The glucocorticoid nano-delivery system was synthesized by a lipid thin film and a simple facile acoustic-emulsification method. This glucocorticoid nano-delivery system used BMS-470539 (BMS-α), a synthetic compound, as a “navigator” to specifically identify and target the melanocortin-1 receptor (MC-1R) on podocytes. The loaded perfluoropentane (PFP) realizes the directed "explosion effect" through ultrasound-targeted microbubble destruction (UTMD) technology under the coordination of low intensity focused ultrasound (LIFU) to completely release Dex.

Results: Both in vitro and in vivo experiments have demonstrated that Dex/PFP@LIPs-BMs-α accurately gathered to podocyte targets and improved podocyte morphology. Moreover, in vivo, proteinuria and serum creatinine levels were significantly reduced in the group treated with Dex/PFP@LIPs-BMS-α, and no severe side effects were detected. Furthermore, Dex/PFP@LIPs-BMS-α, with capabilities of ultrasound, photoacoustic and fluorescence imaging, provided individualized visual guidance and the monitoring of treatment.

Conclusion: This study provides a promising strategy of Dex/PFP@LIPs-BMS-α as effective and safe against immune-associated nephropathy.

Repository corticotropin injection versus corticosteroids for protection against renal damage in a focal segmental glomerulosclerosis rodent model

Background

Focal segmental glomerulosclerosis (FSGS) causes renal fibrosis and may lead to kidney failure. FSGS and its common complication, proteinuria, are challenging to treat. Corticosteroids are ineffective in many patients with FSGS, and alternative treatments often yield suboptimal responses. Repository corticotropin injection (RCI; Acthar® Gel), a naturally sourced complex mixture of purified adrenocorticotropic hormone analogs and other pituitary peptides, may have beneficial effects on idiopathic FSGS via melanocortin receptor activation.

Methods

Two studies in a preclinical (female Sprague-Dawley rats) puromycin aminonucleoside FSGS model assessed the effect of RCI on renal function and morphology: an 8-week comparison of a single RCI dose with methylprednisolone (N = 27), and a 12-week chronic RCI dose range study (N = 34). Primary outcomes were proteinuria and renal pathology improvements for measures of renal fibrosis, tubular damage, glomerular injury, and total kidney injury score. Impact of RCI treatment was also determined by assessing urinary biomarkers for renal injury, podocyte expression of podoplanin (a biomarker for injury), podocyte effacement by electron microscopy, and histological staining for fibrosis biomarkers.

Results

Compared with saline treatment, RCI 30 IU/kg significantly reduced proteinuria, with a 38% reduction in peak mean urine protein levels on day 28 in the 8-week model, and RCI 10 IU/kg, 30 IU/kg, and 60 IU/kg reduced peak mean urine protein in the 12-week model by 18, 47, and 44%, respectively. RCI also showed significant dose-dependent improvements in fibrosis, interstitial inflammation, tubular injury, and glomerular changes. Total kidney injury score (calculated from histopathological evaluations) demonstrated statistically significant improvements with RCI 30 IU/kg in the 8-week study and RCI 60 IU/kg in the 12-week study. RCI treatment improved levels of urinary biomarkers of kidney injury (KIM-1 and OPN), expression of podoplanin, and podocyte morphology. RCI also reduced levels of desmin and fibrosis-associated collagen deposition staining. Methylprednisolone did not improve renal function or pathology in this model.

Conclusions

These results provide evidence supporting the improvement of FSGS with RCI, which was superior to corticosteroid treatment in this experimental model. To the authors’ knowledge, this is the first evidence that a drug for the treatment of FSGS supports podocyte recovery after repeated injury.

ACTH Treatment for Management of Nephrotic Syndrome: A Systematic Review and Reappraisal

BACKGROUND

In recent years, the use of adrenocorticotropic hormone (ACTH) therapy for treatment of proteinuria due to nephrotic syndrome (NS) has been heavily explored. ACTH therapy, which comes in the natural (H. P. Acthar Gel) or synthetic (tetracosactide) form, has resulted in remission in patients with immunosuppressive and steroid-resistant NS. However, the exact efficacy of ACTH therapy in the NS etiologies, such as membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), lupus nephritis (LN), IgA nephropathy (IgAN), and membranoproliferative glomerulonephritis (MPGN), has not been determined.

OBJECTIVE

This systematic review analyzed the published literature on ACTH therapy in various NS etiologies to determine its efficacy.

METHODS

A comprehensive search of MEDLINE, EMBASE, and Cochrane databases was conducted for articles through June 2019. An additional search was performed on clinicaltrials.gov to search for additional trials and cross reference the results of our database search. The literature which studied synthetic or natural ACTH treatment in patients with known etiologies of NS was included. Studies were excluded when they consisted of a single case report or did not analyze the lone effect of ACTH in NS.

RESULTS

The initial search yielded a total of 411 papers, and 22 papers were included. In 214 MN patients, there was an overall remission of 40% (85/214) and an overall remission of 43% (42/98) in FSGS patients. In other etiologies, there were overall remissions of 78% (11/14), 31% (5/16), 40% (16/40), and 62% (8/13) in MCD, LN, IgAN, and MPGN patients, respectively.

CONCLUSION

ACTH showed benefits in proteinuria reduction across all etiologies of NS. However, more randomized controlled studies with larger population sets and longer follow-ups are imperative to establish causal benefits. New studies into its efficacy in children are also necessary.

Melanocortin therapy ameliorates podocytopathy and proteinuria in experimental focal segmental glomerulosclerosis involving a podocyte specific non-MC1R-mediated melanocortinergic signaling

The clinical effectiveness of adrenocorticotropin in inducing remission of steroid-resistant nephrotic syndrome points to a steroidogenic-independent anti-proteinuric activity of melanocortins. However, which melanocortin receptors (MCR) convey this beneficial effect and if systemic or podocyte-specific mechanisms are involved remain uncertain. In vivo, wild-type (WT) mice developed heavy proteinuria and kidney dysfunction following Adriamycin insult, concomitant with focal segmental glomerulosclerosis (FSGS) and podocytopathy, marked by loss of podocin and synaptopodin, podocytopenia and extensive foot process effacement on electron microscopy. All these pathologic findings were prominently attenuated by NDP-MSH, a potent non-steroidogenic pan-MCR agonist. Surprisingly, MC1R deficiency in MC1R-null mice barely affected the severity of Adriamycin-elicited injury. Moreover, the beneficial effect of NDP-MSH was completely preserved in MC1R-null mice, suggesting that MC1R is likely non-essential for the protective action. A direct podocyte effect seems to contribute to the beneficial effect of NDP-MSH, because Adriamycin-inflicted cytopathic signs in primary podocytes prepared from WT mice were all mitigated by NDP-MSH, including apoptosis, loss of podocyte markers, de novo expression of the podocyte injury marker desmin, actin cytoskeleton derangement and podocyte hypermotility. Consistent with in vivo findings, the podoprotective activity of NDP-MSH was fully preserved in MC1R-null podocytes. Mechanistically, MC1R expression was predominantly distributed to glomerular endothelial cells in glomeruli but negligibly noted in podocytes in vivo and in vitro, suggesting that MC1R signaling is unlikely involved in direct podocyte protection. Ergo, melanocortin therapy protects against podocyte injury and ameliorates proteinuria and glomerulopathy in experimental FSGS, at least in part, via a podocyte-specific non-MC1R-mediated melanocortinergic signaling.

Treatment of nephrotic syndrome: going beyond immunosuppressive therapy

It is indisputable that immunosuppressive therapy and pathological diagnosis of renal biopsy have greatly improved the prognosis of childhood nephrotic syndrome. Unfortunately, there is no "one-size-fits-all" approach for precise patient stratification and treatment when facing the huge challenges posed by steroid-resistant nephrotic syndrome (SRNS). But genomic medicine has brought a glimmer of light, and the cognition of SRNS has entered a new stage. Based on this, identification of single genetic variants of SRNS has recognized the key role of podocyte injury in its pathogenesis. Targeted treatment of podocyte injury is paramount, and immunosuppressant with podocyte-targeted therapy seems to be more suitable as the first choice for SRNS, that is, we need to pay attention to their additional non-immunosuppressive effects. In the same way, other effect factors of nephrotic syndrome and the related causes of immunosuppressive therapy resistance require us to select reasonable and targeted non-immunosuppressive therapies, instead of only blindly using steroids and immunosuppressants, which may be ineffective and bring significant side effects. This article provides a summary of the clinical value of identification of genetic variants in podocytes and non-immunosuppressive therapy for nephrotic syndrome in children.

Adrenocorticotropic Hormone in the Treatment of Focal Segmental Glomerulosclerosis Following Kidney Transplantation

This retrospective study examined the effect of adrenocorticotropic hormone therapy on remission of recurrent focal segmental glomerulosclerosis (FSGS) in patients with history of kidney transplant (KT) treated at 2 transplant centers. Patients with biopsy-confirmed FSGS following KT who received Acthar Gel (Mallinckrodt ARD, Bedminster, New Jersey, United States) treatment for ≥1 month were eligible. A total of 14 patients with idiopathic FSGS were included. Acthar Gel treatment resulted in complete remission of FSGS in 3 patients and partial remission in 2 patients for a total treatment response rate of 36% (5/14) of patients. Among patients showing complete or partial remission, Acthar Gel treatment duration ranged from 6 months to 2 years and 60% (3/5 patients) had serum creatinine ≤ 2 mg/dL at the start of Acthar Gel treatment. Patient outcomes suggest Acthar Gel may be an effective and tolerable treatment for recurrent FSGS in patients with history of KT. Early initiation of Acthar Gel treatment and therapy duration of at least 6 months may be needed for optimal response to Acthar Gel in patients with history of KT and recurrent FSGS.

An Open-Label Pilot Study of Adrenocorticotrophic Hormone in the Treatment of IgA Nephropathy at High Risk of Progression

Introduction

IgA nephropathy (IgAN) is the most common glomerulonephritis with high risk of progression to end-stage renal disease in patients with proteinuria >1 g/24 hours. There are no known effective treatments in patients with IgAN.

Methods

We conducted a prospective open-label pilot study in patients with IgAN using adrenocorticotrophic hormone (ACTH) (Acthar Gel, Mallinckrodt Pharmaceuticals, Bedminster, NJ) at a dosage of 80 units subcutaneously twice weekly for a total of 6 months and followed patients for a total of 12 months. Patients had to have urinary protein >1 g/24 hours despite adequate renin-angiotensin-aldosterone system (RAAS) blockade and estimated glomerular filtration rate (eGFR) >30 ml/min at enrollment.

Results

A total of 19 patients were recruited and followed for 1 year. At baseline, the mean age was 34.9 ± 10.5 years with 11 men and 8 women, and 14 Caucasian and 5 Asian individuals. At 12 months, there was a statistically significant decline in 24-hour urinary protein from 2.6 to 1.3 g (P = 0.007) and significant increase in serum albumin (3.79 to 3.93, P = 0.02). There was no significant change in eGFR (65.5 to 61.1 ml/min, P = 0.1). There were 0 complete remissions and 8 partial remissions (42%). There were a total of 6 infections: 2 were viral and 4 required antibiotic therapy (2 sinusitis, 1 pneumonia, 1 otitis media). The most common adverse events included acne, hot flashes, soreness, and anxiety.

Conclusion

In summary, patients with IgAN with >1 g/24-hour urinary protein and eGFR >30 ml/min had a significant reduction in 24-hour urinary protein with stable eGFR at 12-month follow-up after being treated with 6 months of ACTH.

ACTH Gel in Resistant Focal Segmental Glomerulosclerosis After Kidney Transplantation

BACKGROUND

Treatment of focal segmental glomerular sclerosis (FSGS) after kidney transplantation is challenging with unpredictable outcomes. The objective was to investigate the use of adrenocorticotropic hormone (ACTH) analogue gel in kidney transplant recipients with de novo or recurrent FSGS resistant to therapeutic plasma exchange (TPE) and/or rituximab.

METHODS

We performed a retrospective review of cases of de novo or recurrent resistant FSGS at 2 large US transplant centers between April 2012 and December 2016. Proteinuria was measured by urine protein to creatinine ratio.

RESULTS

We identified 20 cases of posttransplant recurrent and de novo FSGS resistant to conventional therapy with TPE and rituximab. Mean ± SD age was 49 ± 15.5 years, 14 (70%) were male, 13 (65%) were whites, and 8 (38%) had previous kidney transplants. Median (interquartile range) of recurrent and de novo FSGS was 3 (0.75-7.5) months posttransplant. The majority of patients, 15 (75%), received TPE as a treatment at the time of diagnosis and 10 (50%) received rituximab, which was started before the use of ACTH gel. There was a significant improvement of urine protein to creatinine ratio from a mean ± SD of 8.6 ± 7.6 g/g before ACTH gel to 3.3 ± 2.3 g/g after the use of ACTH gel (P = 0.004). Ten (50%) patients achieved complete or partial remission.

CONCLUSIONS

Although, the response varied among the recipients, ACTH gel might be an effective therapy for posttransplant resistant FSGS cases that fail to respond to TPE and rituximab.

New strategies and perspectives on managing IgA nephropathy

IgA nephropathy is an inflammatory renal disease characterised by the deposition of IgA in the glomerular mesangium and is the most commonly reported primary glomerulonephritis worldwide. Thirty to forty percent of patients with the disease develop progressive renal function decline, requiring renal replacement therapy within two decades of diagnosis. Despite this, accurate individual risk stratification at diagnosis and predicting treatment response remains a challenge. Furthermore, there are currently no disease specific treatments currently licensed to treat the condition due to long standing challenges in the nature and prevalence of the disease. Despite this, there have been exciting recent advances in the field that may represent paradigm shifts in the way IgA nephropathy is managed in the near future. In this review, we explore the evidence base informing current approaches to management and explore new strategies and future directions in the diagnosis and management of IgA nephropathy.

Use of Repository Corticotropin Gel (Acthar) in Progressive Nephrotic Syndrome Secondary to Transplant Glomerulopathy: A Report of Three Cases

Transplant glomerulopathy is a feared complication of kidney transplantation, often resulting in rapid loss of kidney function and ultimate graft failure. The underlying cause is unclear, with both antibody and cell-mediated immune mechanisms postulated, as well as intrinsic glomerular factors. At the present time, there is no known therapy. We report here 3 cases in which corticotropin gel (Acthar) was used with varying response of proteinuria and stabilization of graft function with continued graft survival as long as 10 years following the diagnosis. Future randomized controlled trials are warranted to examine the efficacy and safety of ACTH gel therapy in nephrotic patients with transplant glomerulopathy.

Emerging therapeutic strategies for minimal change disease and focal and segmental glomerulosclerosis

INTRODUCTION

Minimal change disease (MCD) and Focal and segmental glomerulosclerosis (FSGS) are two of the major causes of nephrotic syndrome (NS) in children and adults. According to KDIGO (Kidney Disease: Improving Global Outcomes) guidelines, the treatment of adult primary MCD and FSGS should be based on immunosuppressants and antiproteinuric drugs. Recently, Rituximab, a humanized monoclonal antibody (mAb) has emerged as a potential treatment for steroid or calcineurin inhibitor-dependent patients; it has however demonstrated lower efficacy in those with nephrotic syndrome that is resistant to the above indicated drugs.

AREAS COVERED

Analysis of ongoing and already completed clinical trials, retrieved from clinicaltrials.gov, clinicaltrialsregister.eu and PubMed involving new therapies for nephrotic syndrome secondary to MCD and FSGS.

EXPERT OPINION

The most promising drugs under investigation for MCD and FSGS are mAbs. We are hopeful that new therapeutic options to treat multi-drug resistant MCD and FSGS will emerge from currently ongoing studies. What appears certain is the difficulty in enrolling patients affected by orphan renal diseases and the selection of valid endpoints in clinical trials, such as kidney failure.

Amplification of the Melanocortin-1 Receptor in Nephrotic Syndrome Identifies a Target for Podocyte Cytoskeleton Stabilization

The melanocortin-1 receptor (MC1R) in podocytes has been suggested as the mediator of the ACTH renoprotective effect in patients with nephrotic syndrome with the mechanism of action beeing stabilization of the podocyte actin cytoskeleton. To understand how melanocortin receptors are regulated in nephrotic syndrome and how they are involved in restoration of filtration barrier function, melanocortin receptor expression was evaluated in patients and a rat model of nephrotic syndrome in combination with cell culture analysis. Phosphoproteomics was applied and identified MC1R pathways confirmed using biochemical analysis. We found that glomerular MC1R expression was increased in nephrotic syndrome, both in humans and in a rat model. A MC1R agonist protected podocytes from protamine sulfate induced stress fiber loss with the top ranked phoshoproteomic MC1R activated pathway beeing actin cytoskeleton signaling. Actin stabilization through the MC1R consisted of ERK1/2 dependent phosphorylation and inactivation of EGFR signaling with stabilization of synaptopodin and stressfibers in podocytes. These results further explain how patients with nephrotic syndrome show responsiveness to MC1R receptor activation by decreasing EGFR signaling and as a consequence restore filtration barrier function by stabilizing the podocyte actin cytoskeleton.

Therapy for Proliferative Lupus Nephritis

Proliferative lupus nephritis requires prompt diagnosis and treatment with immunosuppressive therapy. Cyclophosphamide is the longest studied agent, but mycophenolate mofetil has recently emerged as an efficacious induction and maintenance treatment that does not impart the risk of infertility. However, overall remission rates remain suboptimal and there is a need for improved therapeutic options. To this end, ongoing clinical studies are focusing on agents that target key molecules and pathways implicated in the pathogenesis of lupus nephritis based on previous animal and human studies. This article reviews key findings of trials supporting established induction and maintenance treatment regimens along with novel therapeutic investigations.

Protecting Podocytes: A Key Target for Therapy of Focal Segmental Glomerulosclerosis

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is a histologic pattern of injury demonstrated by renal biopsy that can arise from a diverse range of causes and mechanisms. It has an estimated incidence of 7 per 1 million and is the most common primary glomerular disorder leading to end-stage renal disease in the United States. This review focuses on damage to the podocyte and the consequences of this injury in patients with FSGS, the genetics of FSGS, and approaches to treatment with a focus on the effects on podocytes.

SUMMARY

The podocyte is central to the glomerular filtration barrier and is particularly vulnerable because of its highly differentiated post-mitotic phenotype. The progressive structural changes involved in the pathology of FSGS include podocyte foot process effacement, death of podocytes and exposure of the glomerular basement membrane, filtration of nonspecific plasma proteins, expansion of capillaries, misdirected filtration at points of synechiae, and mesangial matrix proliferation. Although damage to and death of podocytes can result from single-gene disorders, evidence also suggests a role for soluble factors, such as soluble urokinase-type plasminogen activator receptor, cardiotrophin-like cytokine-1, and anti-CD40 antibodies, that promote FSGS recurrence post transplant. Several classes of medications, including corticosteroids, calcineurin inhibitors, endothelin receptor antagonists, adrenocorticotropic hormone, and rituximab, have been shown to be effective for the treatment of FSGS and have been demonstrated to have significant protective effects on podocytes. Key Messages: Greater understanding of podocyte biology is essential to the identification of new treatment targets and medications for the management of patients with FSGS.

Use of synthetic adrenocorticotropic hormone in patients with IgA nephropathy

Background

Synthetic adrenocorticotropic hormone (ACTH) has been demonstrated to be effective in patients with membranous nephropathy, minimal change disease and some histological subtypes of focal segmental glomerulosclerosis. Its clinical impact in patients with IgA nephropathy is currently unclear.

Case presentation

In this report, we describe the clinical use of ACTH in patients with IgA nephropathy. Three female patients (24–44 years) with overt proteinuria received intramuscular (IM) ACTH for varying time periods (8–14 months). Pre-treatment urine protein varied from 2.9 g/d to 4.3 g/d.

Conclusions

There was complete remission in one patient on ACTH monotherapy and in the other two when prescribed as a steroid-sparing agent in combination with cyclophosphamide. All three had resolution in proteinuria to less than 1 g/d and maintained their GFR to baseline values. There were no reported side effects at a once a week dose. This study illustrates that ACTH is an effective agent that is well tolerated with minimal side effects and can be used as an alternative to prednisone in patients with IgA nephropathy.

Treatment of primary membranous nephropathy: where are we now?

In the last 10 years, basic science and clinical research have made important contributions to the understanding and management of primary membranous nephropathy (MN). The identification of antibodies directed against the M-type phospholipase A₂ receptor (PLA2R) and thrombospondin type-1 domain-containing 7A protein have added a new perspective on diagnosis, monitoring the immunological activity, predicting prognosis and guiding therapy in patients with primary MN. Mounting evidence suggests that quantification and follow-up of antiPLA2R Abs levels can help in assessing prognosis and evaluate the response to treatment. The kidney disease improving global outcomes guidelines published in 2012 have not been updated. New data on the use of rituximab suggest it should be considered as a potential initial therapy in the treatment of patients with primary MN.

Multiple Targets for Novel Therapy of FSGS Associated with Circulating Permeability Factor

A plasma component is responsible for altered glomerular permeability in patients with focal segmental glomerulosclerosis. Evidence includes recurrence after renal transplantation, remission after plasmapheresis, proteinuria in infants of affected mothers, transfer of proteinuria to experimental animals, and impaired glomerular permeability after exposure to patient plasma. Therapy may include decreasing synthesis of the injurious agent, removing or blocking its interaction with cells, or blocking signaling or enhancing cell defenses to restore the permeability barrier and prevent progression. Agents that may prevent the synthesis of the permeability factor include cytotoxic agents or aggressive chemotherapy. Extracorporeal therapies include plasmapheresis, immunoadsorption with protein A or anti-immunoglobulin, or lipopheresis. Oral or intravenous galactose also decreases P_alb activity. Studies of glomeruli have shown that several strategies prevent the action of FSGS sera. These include blocking receptor-ligand interactions, modulating cell reactions using indomethacin or eicosanoids 20-HETE or 8,9-EET, and enhancing cytoskeleton and protein interactions using calcineurin inhibitors, glucocorticoids, or rituximab. We have identified cardiotrophin-like cytokine factor 1 (CLCF-1) as a candidate for the permeability factor. Therapies specific to CLCF-1 include potential use of cytokine receptor-like factor (CRLF-1) and inhibition of Janus kinase 2. Combined therapy using multiple modalities offers therapy to reverse proteinuria and prevent scarring.

Investigational drugs in development for focal segmental glomerulosclerosis

INTRODUCTION

Focal segmental glomerulosclerosis is an important cause of end stage kidney disease and is a paradigm for the study of glomerular scarring. There are no FDA approved treatments for this condition. Current therapies, assessed based on reduction in proteinuria, are generally effective in a subset of patients which suggests that FSGS is a heterogeneous group of glomerular disorders or podocytopathies that converge on a common histopathological phenotype. Areas covered: We searched for investigational drugs agents that target different pathophysiological pathways using the key words 'FSGS' and 'podocyte' in American and European clinical trial registers (clinicaltrials.gov; clinicaltrialsregister.eu). Published articles were searched in PubMed, Medline, the Web of Science and the Cochrane Central Register of Controlled Trials Library. Expert opinion: Progress is being made in defining the mechanism of action of subtypes of FSGS. Current and investigational therapies for FSGS target these different pathways of injury. It is anticipated that advances in systems biology will further refine the classification of FSGS by subdividing the disease based on the primary mechanism of glomerular injury, identify biomarkers to discriminate between different subtypes, and enable appropriate selection of appropriate therapy for each individual in accordance with the goals of precision medicine.

Safety and Efficacy of Combination ACTHar Gel and Tacrolimus in Treatment-Resistant Focal Segmental Glomerulosclerosis and Membranous Glomerulopathy

Introduction

H.P. ACTHar gel is a preparation of melanocortin peptides that has been used to treat resistant forms of nephrotic syndrome. To determine whether combination therapy with ACTHar gel and tacrolimus reduces proteinuria and stabilizes renal function, we conducted a prospective, open-label trial in patients with treatment-resistant membranous glomerulopathy (MGN) and focal segmental glomerulosclerosis (FSGS).

Methods

Nine patients with treatment-resistant MGN and 13 with treatment-resistant FSGS received subcutaneous ACTHar gel for 6 months. Patients with no response or a partial response to ACTHar gel alone received an additional 6 months of therapy with combination ACTHar gel and oral tacrolimus. The study endpoint was the percentage of patients achieving a complete or partial remission after 6 months of combination therapy.

Results

Among patients with MGN, treatment with ACTHar gel alone achieved a partial remission in 44% and no response in 56% of patients. No patient achieved a complete response with ACTHar gel therapy alone. An additional 6 months of combination therapy with ACTHar gel and tacrolimus resulted in partial and complete response rates of 25% and 75%, respectively. Among patients with FSGS, ACTHar gel therapy alone resulted in complete and partial response rate of 7.7% and 62.0%. Combination therapy increased complete response rates to 17% and partial responses to 66%. Proteinuria (urinary protein-to-creatinine ratio) was significantly reduced in both patients with MGN and those with FSGS after 6 months of ACTHar gel alone and was further reduced among the patients with MGN with the addition of tacrolimus. There were no significant changes in estimated glomerular filtration rate during the treatment phase or long-term follow-up.

Discussion

Combination therapy with ACTHar gel and tacrolimus was well tolerated by patients with treatment-resistant MGN and FSGS and significantly reduced proteinuria and improved clinical response rates compared with ACTHar gel alone.

Adrenocorticotropic hormone analog use for podocytopathies

BACKGROUND

Adrenocorticotropic hormone is being increasingly studied for treatment of various glomerulopathies, most notably membranous nephropathy. Less data are available regarding its use in idiopathic nephrotic syndrome (INS) secondary to minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS). We report here our experience with H.P. Acthar(®) Gel (repository corticotropin injection) as first-line or subsequent therapy in patients with INS.

METHODS

Data were taken from three patients with MCD and ten patients with FSGS from around the US, who were treated with Acthar Gel as initial or subsequent therapy. Treatment was solely at the discretion of the primary nephrologist without a specific protocol. A complete response (CR) was defined as final urine protein-to-creatinine ratio <500 mg/g and a partial response (PR) as 50% decrease without rise of serum creatinine. Side effects and tolerability were noted.

RESULTS

All three patients with MCD received Acthar Gel as second-line or later immunosuppressive (IS) therapy and all responded (one CR and two PRs). Two of the ten patients with FSGS received Acthar Gel as first-line IS therapy, while the other eight had failed multiple agents. Four of the ten patients with FSGS had responses, including two CRs and two PRs. The three patients with MCD tolerated therapy well without side effects. Five patients with FSGS tolerated therapy well, while five had various steroid-like side effects, resulting in therapy discontinuation in two patients.

CONCLUSION

Acthar Gel is a viable alternative IS agent for treatment of INS in patients intolerant or resistant to conventional therapy. More data are needed to better define its appropriate place.

MC1R is dispensable for the proteinuria reducing and glomerular protective effect of melanocortin therapy

Melanocortin therapy by using adrenocorticotropic hormone (ACTH) or non-steroidogenic melanocortin peptides attenuates proteinuria and glomerular injury in experimental glomerular diseases and induces remission of nephrotic syndrome in patients with diverse glomerulopathies, even those resistant to steroids. The underlying mechanism remains elusive, but the role of melanocortin 1 receptor (MC1R) has been implicated and was examined here. Four patients with congenital red hair color and nephrotic syndrome caused by idiopathic membranous nephropathy or focal segmental glomerulosclerosis were confirmed by gene sequencing to bear dominant-negative MC1R mutations. Despite prior corticosteroid resistance, all patients responded to ACTH monotherapy and ultimately achieved clinical remission, inferring a steroidogenic-independent and MC1R-dispensable anti-proteinuric effect of melanocortin signaling. In confirmatory animal studies, the protective effect of [Nle⁴, D-Phe⁷]-α-melanocyte stimulating hormone (NDP-MSH), a potent non-steroidogenic pan-melanocortin receptor agonist, on the lipopolysaccharide elicited podocytopathy was completely preserved in MC1R-null mice, marked by reduced albuminuria and diminished histologic signs of podocyte injury. Moreover, in complementary in vitro studies, NDP-MSH attenuated the lipopolysaccharide elicited apoptosis, hypermotility and impairment of filtration barrier function equally in primary podocytes derived from MC1R-null and wild-type mice. Collectively, our findings suggest that melanocortin therapy confers a proteinuria reducing and podoprotective effect in proteinuric glomerulopathies via MC1R-independent mechanisms.

Efficacy and safety of adrenocorticotropic hormone treatment in glomerular diseases: a systematic review and meta-analysis

BACKGROUND

There is growing evidence that adrenocorticotropic hormone (ACTH) may be effective in treating various forms of glomerular diseases. However, the efficacy of treatment and frequency of adverse effects associated with the use of ACTH in glomerular diseases are unknown. A systematic review and meta-analysis of the literature was performed.

METHODS

A literature search was performed using Medline, Embase, Google Scholar and the Cochrane Database of Systematic Reviews from inception through 18 July 2015. Studies assessing the efficacy and safety of ACTH treatment in adults with glomerular diseases were included.

RESULTS

Of the 343 identified citations, 18 evaluated the drug efficacy and 12 evaluated the adverse effects. The most common glomerular diseases were membranous nephropathy (MN), primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD). The overall rate of complete remission in MN was 80% at 0-6 months, 69% at >6-12 months, 90% at >12-24 months and 95% beyond 24 months of follow-up. Fifty percent of primary FSGS and MCD patients treated with ACTH were in remission at 6 months, but the relapse rate was high after ACTH discontinuation (17%). Evidence of ACTH efficacy for other glomerular diseases was scarce. Edema was the most commonly reported adverse effect {incidence rate [IR] 0.10 [95% confidence interval (CI) 0.04-0.18]} followed by insomnia [IR 0.08 (95% CI 0.03-0.15)]. The dropout rate due to adverse events was 7%, mostly due to edema and weight gain.

CONCLUSIONS

ACTH is a well-tolerated therapy and is most promising when treating patients with MN. There may be a potential role for ACTH in patients with MCD and FSGS, but data are lacking.

Drug discovery in focal and segmental glomerulosclerosis

Despite the high medical burden experienced by patients with focal segmental glomerulosclerosis, the etiology of the condition remains largely unknown. Focal segmental glomerulosclerosis is highly heterogeneous in clinical and morphologic manifestations. While this presents challenges for the development of new treatments, research investments over the last 2 decades have yielded a surfeit of potential avenues for therapeutic intervention. The development of many of those ideas and concepts into new therapies, however, has been very disappointing. Here, we describe some of the factors that have potentially contributed to the poor translational performance from this research investment, including the confidence we ascribe to a target, the conduct of experimental studies, and the availability of selective reagents to test hypotheses. We will discuss the significance of genetic and systems traits as well as other methods for reducing bias. We will analyze the limitations of a successful drug development. We will use specific examples hoping that these will guide a consensus for investment and drive greater translational quality. We hope that this substrate will serve to exemplify the tremendous opportunity for intervention as well as facilitate greater collaborative effort between industry, academia, and private foundations in promoting appropriate validation of these targets. Only then will we have achieved our goal for curative therapies for this devastating disease.

The podocyte as a direct target for treatment of glomerular disease?

The Centers for Disease Control and Prevention estimates more than 10% of adults in the United States, over 20 million Americans, have chronic kidney disease (CKD). A failure to maintain the glomerular filtration barrier directly contributes to the onset of CKD. The visceral epithelial cells, podocytes, are integral to the maintenance of this renal filtration barrier. Direct podocyte injury contributes to the onset and progression of glomerular diseases such as minimal change disease (MCD), focal segmental glomerular sclerosis (FSGS), diabetic nephropathy, and HIV-associated nephropathy (HIVAN). Since podocytes are terminally differentiated with minimal capacity to self-replicate, they are extremely sensitive to cellular injury. In the past two decades, our understanding of the mechanism(s) by which podocyte injury occurs has greatly expanded. With this newfound knowledge, therapeutic strategies have shifted to identifying targets directed specifically at the podocyte. Although the systemic effects of these agents are important, their direct effect on the podocyte proves to be essential in ameliorating glomerular disease. In this review, we highlight the mechanisms by which these agents directly target the podocyte independent of its systemic effects.

Adrenocorticotropic hormone therapy for the treatment of idiopathic nephrotic syndrome in children and young adults: a systematic review of early clinical studies with contemporary relevance

Adrenocorticotropic hormone (ACTH) as a treatment for proteinuria due to nephrotic syndrome (NS) has re-emerged over the last decade. Current clinical data are primarily limited to adults with treatment-resistant NS. Largely unknown to today's clinicians is the existence of early clinical studies, following ACTH's introduction in the late 1940s, showing sustained proteinuria response in idiopathic NS in predominantly pediatric, treatment-naïve patients. Before ACTH, patients suffered severe edema and high mortality rates with no reliable or safe treatment. ACTH dramatically altered NS management, initially through recognition of diuresis effects and then through sustained proteinuria remission. This review synthesizes early clinical literature to inform current NS patient management. We undertook a MEDLINE search using MeSH terms "adrenocorticotropic hormone" and "nephrotic syndrome," with limits 1945-1965 and English. Sixty papers totaling 1137 patients were found; 14 studies (9 short-term, five long-term, N = 419 patients) met inclusion criteria. Studies were divided into two groups: short-term (≤28 days) and long-term (>5 weeks; short-term initial daily treatment followed by long-term intermittent)ACTH therapy and results were aggregated. An initial response, defined as a diuresis, occurred in 74 % of patients/treatment courses across nine short-term ACTH studies. Analyzed in eight of these studies, proteinuria response occurred in 56 % of patients/treatment courses. Across five long-term ACTH studies, proteinuria response was shown in 71 % of patients and was sustained up to 4.7 years following treatment. The inventory and re-evaluation of early clinical data broadens the evidence base of clinical experiences with ACTH for implementation of current treatment strategies and aiding the design of future studies.

Acthar gel in the treatment of nephrotic syndrome: a multicenter retrospective case series

Background

Current first-line anti-proteinuric treatments for nephrotic syndrome (NS) do not produce an effective response in all patients and are not tolerated by some patients. Additional effective and tolerable treatment options in NS are strongly needed. This retrospective case series is the largest to date to examine Acthar gel (adrenocorticotropic hormone, ACTH) in patients with varied-etiology NS.

Methods

This multicenter retrospective case series included adult patients with NS (N = 44) treated with Acthar gel at 6 clinical practices. NS etiologies included idiopathic focal segmental glomerulosclerosis (FSGS, 15), idiopathic membranous nephropathy (iMN, 11), IgA nephropathy (IgAN, 5), diabetic nephropathy (DN, 4), systemic lupus erythematosus class V membranous lupus nephritis (MLN, 2), minimal change disease (MCD, 2), membranoproliferative glomerulonephritis (MPGN, 1), fibrillary glomerulonephritis (FGN, 1), and unbiopsied NS (3). Proteinuria response was assessed as percent reduction from baseline and percent of patients meeting complete remission (final proteinuria <500 mg/d), partial remission (≥50 % reduction in proteinuria from baseline and final proteinuria 500–3500 mg/d), clinical response (≥30 % reduction in proteinuria from baseline that did not meet criteria for complete or partial remission), and no response (failed to meet remission or clinical response criteria) following Acthar gel therapy. Safety and tolerability were examined using adverse event (AE) frequency reported by patients or treating nephrologists and frequency of early discontinuation of treatment due to AEs.

Results

68.2 % (30/44) of patients had received prior NS treatment with immunosuppressive or cytotoxic therapies. Thirty-seven patients completed Acthar gel treatment. Seven patients (15.9 %) had early termination due to AEs, including weight gain (2), hypertension (2), edema (1), fatigue (1), seizures (1) and for reasons not stated (2). Proteinuria reduction ≥30 % was shown in 81.1 % (30/37) of patients and 62.2 % (23/37) showed ≥50 % proteinuria reduction. Proteinuria responses were greatest in MCD (n = 2/2 complete remission), MLN (n = 2/2 partial remission), MPGN (n = 1/1 partial remission), FSGS (n = 12/15 [80.0 %] partial remission or clinical response), and iMN (n = 8/11 [72.7 %] complete remission, partial remission, or clinical response).

Conclusions

Acthar gel may meet an important treatment need in patients with treatment-resistant NS in response to first-line therapies, patients unable to tolerate first-line therapies, and in patients with advanced disease.

Melanocortin 1 receptor agonist protects podocytes through catalase and RhoA activation

Drugs containing adrenocorticotropic hormone have been used as therapy for patients with nephrotic syndrome. We have previously shown that adrenocorticotropic hormone and a selective agonist for the melanocortin 1 receptor (MC1R) exert beneficial actions in experimental membranous nephropathy with reduced proteinuria, reduced oxidative stress, and improved glomerular morphology and function. Our hypothesis is that MC1R activation in podocytes elicits beneficial effects by promoting stress fibers and maintaining podocyte viability. To test the hypothesis, we cultured podocytes and used highly specific agonists for MC1R. Podocytes were subjected to the nephrotic-inducing agent puromycin aminonucleoside, and downstream effects of MC1R activation on podocyte survival, antioxidant defense, and cytoskeleton dynamics were studied. To increase the response and enhance intracellular signals, podocytes were transduced to overexpress MC1R. We showed that puromycin promotes MC1R expression in podocytes and that activation of MC1R promotes an increase of catalase activity and reduces oxidative stress, which results in the dephosphorylation of p190RhoGAP and formation of stress fibers through RhoA. In addition, MC1R agonists protect against apoptosis. Together, these mechanisms protect the podocyte against puromycin. Our findings strongly support the hypothesis that selective MC1R-activating agonists protect podocytes and may therefore be useful to treat patients with nephrotic syndromes commonly considered as podocytopathies.

Melanocortin peptides: potential targets in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease resulting in loss of self-tolerance with multiple organs, such as the kidney, skin, joints, and the central nervous system (CNS), being targeted. Numerous immunosuppressant therapies are currently being used for the treatment of SLE, but their clinical utility is somewhat variable because of the clinical heterogeneity. Melanocortins are a family of peptides derived from the common precursor protein pro-opiomelanocortin. These multifunctional peptides activate five subtypes of melanocortin receptors expressed on immune, skin, muscle, bone, and kidney cells and cells within the CNS. Melanocortin peptides have demonstrated a variety of biologic actions including immunomodulation, melanogenesis, and renoprotection. This review aims to introduce the melanocortin system and explore the mechanisms by which they may be beneficial in diseases such as SLE.

Synthetic ACTH in High Risk Patients with Idiopathic Membranous Nephropathy: A Prospective, Open Label Cohort Study

New therapeutic agents are warranted in idiopathic membranous nephropathy. Synthetic ACTH may be advantageous with reported remission rates up to 85% and few side effects. We conducted a prospective open label cohort study from 2008 till 2010 (NCT00694863). We prospectively selected patients with idiopathic membranous nephropathy and high risk for progression (defined as βeta-2-microglobulin (β2m) excretion of >500 ng/min). For comparison, we selected matched historical controls treated with cyclophosphamide. The prospectively selected patients received intramuscular injections of synthetic ACTH during 9 months (maximal dose 1 mg twice a week). The primary endpoints concerned the feasibility and incidence of remissions as a primary event. Secondary endpoints included side effects of treatment and the incidence of remissions and relapses at long-term follow-up. Twenty patients (15 men) were included (age 54±14 years, serum creatinine 104 μmol/l [IQR 90–113], urine protein:creatinine ratio 8.7 g/10 mmol creatinine [IQR 4.3–11.1]). Seventeen patients (85%) completed treatment. 97% of injections were administered correctly. Cumulative remission rate was 55% (complete remission in 4 patients, partial remission 7 patients). In a group of historical controls treated with cyclophosphamide and steroids, 19 of 20 patients (95%) developed a remission (complete remission in 13 patients, partial remission in 6 patients) (p<0.01). The main limitation of our study is its small size and the use of a historical control group. We show that treatment with intramuscular injections of synthetic ACTH is feasible. Our data suggest that synthetic ACTH is less effective than cyclophosphamide in inducing a remission in high risk patients with idiopathic membranous nephropathy. The use of synthetic ACTH was also associated with many adverse events. Therefore, we advise against synthetic ACTH as standard treatment in membranous nephropathy.

Management of Membranous Nephropathy in Western Countries

BACKGROUND

Idiopathic membranous nephropathy (IMN) is a common cause of nephrotic syndrome (NS) in adults in Western countries. In 2012, the KDIGO (Kidney Disease: Improving Global Outcomes) working group published guidelines for the management of glomerulonephritis, thus providing a template for the treatment of this condition. While being aware of the impact of the clinicians' acumen and that patients may choose a different therapeutic option due to the risks of specific drugs and also of the evolving guidelines, this review details our approach to the management of patients with IMN in a Western center (Toronto).

SUMMARY

Based on studies published in Europe and North America, we included recent advances in the diagnosis and management of patients with membranous nephropathy similar to our practice population. We highlight the importance of establishing the idiopathic nature of this condition before initiating immunosuppressive therapy, which should include the screening for secondary causes, especially malignancy in the elderly population. The expected outcomes with and without treatment for patients with different risks of progression will be discussed to help guide clinicians in choosing the appropriate course of treatment. The role of conservative therapy as well as of established immunosuppressive treatment, such as the combination of cyclophosphamide and prednisone, and calcineurin inhibitors (CNIs), as well as of newer agents such as rituximab will be reviewed.

KEY MESSAGES

Appropriate assessment is required to exclude secondary conditions causing membranous glomerulonephritis. The role of antibodies to phospholipase A2 receptor (anti-PLA2R) in establishing the primary disease is growing, though more data are required. The increase in therapeutic options supports treatment individualization, taking into account the availability, benefits and risks, as well as patient preference.

FACTS FROM EAST AND WEST

(1) The prevalence of IMN is increasing worldwide, particularly in elderly patients, and has been reported in 20.0-36.8% of adult-onset NS cases. The presence of anti-PLA2R antibodies in serum or PLA2R on renal biopsy is the most predictive feature for the diagnosis of IMN and is used in both the East and West; however, appropriate screening to rule out secondary causes should still be performed. (2) Several observational (nonrandomized) Asian studies indicate a good response to corticosteroids alone in IMN patients, although no randomized controlled trials (RCTs) have been done in Asian membranous patients at high risk of progression. Corticosteroid monotherapy has failed in randomized controlled studies in Western countries and is therefore not recommended. (3) Cyclophosphamide is the most commonly prescribed alkylating agent in Europe and China. Also, chlorambucil is still used in some Western countries, particularly in Europe. In North America, CNIs are the more common first-line treatment. (4) Cyclosporine is predominantly used as monotherapy in North America, although KDIGO and Japanese guidelines still recommend a combination with low-dose corticosteroids. Clinical studies both in Asia and Europe showed no or little effects of monotherapy with mycophenolate mofetil compared to standard therapies. (5) There are encouraging data from nonrandomized Western studies for the use of rituximab and a few small studies using adrenocorticotropic hormone. Clinical trials are ongoing in North America to confirm these observations. These drugs are rarely used in Asia. (6) A Chinese study reported that 36% of IMN patients suffered from venous thromboembolism versus 7.3% in a North American study. Prophylactic anticoagulation therapy is usually added to IMN patients with a low risk of bleeding in both Eastern and Western countries. (7) The Chinese traditional medicine herb triptolide, which might have podocyte-protective properties, is used in China to treat IMN. An open-label, multicenter RCT showed that Shenqi, a mixture of 13 herbs, was superior to corticosteroids plus cyclophosphamide therapy to restore epidermal growth factor receptor in IMN patients, although proteinuria improvement was equal in the two groups. Importantly, Shenqi treatment induced no severe adverse events while standard therapy did.

A review of the re-emergence of adrenocorticotrophic hormone therapy in glomerular disease, more than a drug of last resort?

There has been a re-emergence of interest in adrenocorticotropic hormone (ACTH) in patients with resistant nephrotic syndrome. We describe a patient with severe nephrosis and advanced chronic kidney disease with idiopathic membranous nephropathy resistant to conventional immunosuppressive therapies that achieved lasting remission with ACTH therapy. We explore the literature showing the extra renoprotective effects which might explain the response of proteinuric renal diseases to this treatment.

Variants of SCARB1 and VDR Involved in Complex Genetic Interactions May Be Implicated in the Genetic Susceptibility to Clear Cell Renal Cell Carcinoma

The current data are still inconclusive in terms of a genetic component involved in the susceptibility to renal cell carcinoma. Our aim was to evaluate 40 selected candidate polymorphisms for potential association with clear cell renal cell carcinoma (ccRCC) based on independent group of 167 patients and 200 healthy controls. The obtained data were searched for independent effects of particular polymorphisms as well as haplotypes and genetic interactions. Association testing implied position rs4765623 in the SCARB1 gene (OR = 1.688, 95% CI: 1.104-2.582, P = 0.016) and a haplotype in VDR comprising positions rs739837, rs731236, rs7975232, and rs1544410 (P = 0.012) to be the risk factors in the studied population. The study detected several epistatic effects contributing to the genetic susceptibility to ccRCC. Variation in GNAS1 was implicated in a strong synergistic interaction with BIRC5. This effect was part of a model suggested by multifactor dimensionality reduction method including also a synergy between GNAS1 and SCARB1 (P = 0.036). Significance of GNAS1-SCARB1 interaction was further confirmed by logistic regression (P = 0.041), which also indicated involvement of SCARB1 in additional interaction with EPAS1 (P = 0.008) as well as revealing interactions between GNAS1 and EPAS1 (P = 0.016), GNAS1 and MC1R (P = 0.031), GNAS1 and VDR (P = 0.032), and MC1R and VDR (P = 0.035).

Repository corticotropin injection in a patient presenting with focal segmental glomerulosclerosis, rheumatoid arthritis, and optic neuritis: a case report

Background

Focal segmental glomerulosclerosis (FSGS) causes scarring or sclerosis of glomeruli that act as tiny filters in the kidneys, damage to which results in diminished ability to properly filter blood, resulting in the urinary loss of plasma proteins and subsequent proteinuria.

Case presentation

A 60-year-old, white female with a history of intermittent proteinuria was referred by her primary care physician for renal dysfunction. Biopsy confirmed FSGS and she was treated with an angiotensin-converting enzyme inhibitor. She also had rheumatoid arthritis (RA) but no active synovitis and was maintained on prednisone 5 mg/d. She also complained of worsening vision in her right eye and was diagnosed with optic neuritis (ON). She remained stable for about 8 months when examination indicated FSGS relapse, and she reported painful RA flares. She was treated with Acthar^® Gel (40 mg biweekly) for 6 months, after which proteinuria and urine protein-to-creatinine ratio decreased to about half. Her ON improved, and she reported that she had fewer RA flares and pain improved by 50%. This case of confirmed FSGS showed an improved response to treatment with Acthar Gel for FSGS with concomitant RA and ON.

Conclusion

This referral case is relevant to primary care practitioners who treat disorders that may be responsive to corticosteroid therapy. The antiproteinuric effects and ancillary improvement in RA and ON symptoms during treatment with Acthar Gel are not entirely explained by its steroidogenic actions. ACTH is a bioactive peptide that, together with α-melanocyte-stimulating hormone, exhibits biologic efficacy by modulating proinflammatory cytokines and subsequent leukocyte extravasation and may have autocrine/paracrine effects in joints. While Acthar Gel was primarily administered in this case to treat proteinuria, it also showed ancillary benefits in patients with concomitant inflammatory disease states.

Novel therapies for FSGS: preclinical and clinical studies

Focal segmental glomerulosclerosis (FSGS) is a rare but important cause of end-stage kidney disease in children and adults. Current therapy, consisting of corticosteroids and calcineurin inhibitors, fails to achieve a sustained remission in most patients. Therefore, there is a pressing need to develop new treatments for this glomerulopathy. Traditional approaches have focused on agents that modulate the immune system. In this review, we summarize preclinical and clinical data with newer agents that may ameliorate FSGS. We focus on drugs that inhibit immune injury or inflammation, such as abatacept, rituximab, adalimumab, and stem cells. The potential of agents that block the glomerular action of circulating permeability factors such as soluble urokinase receptor is reviewed. Finally, because fibrosis represents the final common pathway of glomerular damage in FSGS, the experience with a wide range of antifibrotic agents is presented. Despite extensive research on the podocyte dysfunction in the pathogenesis of FSGS, there are few agents that directly target podocyte structure or viability. We conclude that FSGS is a heterogeneous disorder and that intensified translational research is vital to improve our understanding of distinct subtypes that have a defined prognosis and predictable response to targeted therapeutic interventions.

Low-dose synthetic adrenocorticotropic hormone-analog therapy for nephrotic patients: results from a single-center pilot study

INTRODUCTION

This report describes our experience using a low-dose synthetic adrenocorticotropic hormone (ACTH) analog for patients affected by nephrotic syndrome who had not responded to or had relapsed after steroid and immunosuppressive treatments.

PATIENTS AND METHODS

Eighteen adult nephrotic patients with an estimated glomerular filtration rate >30 mL/min were recruited. Histological pictures included ten of membranous nephropathy, three of membranous proliferative glomerulonephritis, three of minimal change, and two of focal segmental glomerular sclerosis. All patients received the synthetic ACTH analog tetracosactide 1 mg intramuscularly once a week for 12 months. Estimated glomerular filtration rate, proteinuria, serum lipids, albumin, glucose, and potassium were determined before and during the treatment.

RESULTS

One of the 18 patients discontinued the treatment after 1 month because of severe fluid retention, and two patients were lost at follow-up. Complete remission occurred in six cases, while partial remission occurred in four cases (55.5% responder rate). With respect to baseline, after 12 months proteinuria had decreased from 7.24±0.92 to 2.03±0.65 g/day (P<0.0001), and serum albumin had increased from 2.89±0.14 to 3.66±0.18 g/dL (P<0.0001). Total and low-density lipoprotein cholesterol had decreased from 255±17 to 193±10 mg/dL (P=0.01), and from 168±18 to 114±7 mg/dL (P=0.03), respectively. No cases of severe worsening of renal function, hyperglycemia, or hypokalemia were observed, and no admissions for cardiovascular or infectious events were recorded.

CONCLUSION

Tetracosactide administration at the dosage of 1 mg intramuscularly per week for 12 months seems to be an acceptable alternative for nephrotic patients unresponsive or relapsing after steroid-immunosuppressive regimens. Further studies should be planned to assess the effect of this low-dose ACTH regimen also in nephrotic patients not eligible for kidney biopsy or immunosuppressive protocols.