Glucocorticoids in the Treatment of Glomerular Diseases: Pitfalls and Pearls

Corticosteroid therapy for nephrotic syndrome in children

BACKGROUND

In nephrotic syndrome protein leaks from blood into the urine through the glomeruli resulting in hypoproteinaemia and generalised oedema. While most children with nephrotic syndrome respond to corticosteroids, 80% experience a relapsing course. Corticosteroids have reduced the death rate to around 3%. However, corticosteroids have well recognised potentially serious adverse effects such as obesity, poor growth, hypertension, diabetes mellitus, osteoporosis, and behavioural disturbances. This is an update of a review first published in 2000 and updated in 2002, 2005, 2007, and 2015.

OBJECTIVES

The aim of this review was to assess the benefits and harms of different corticosteroid regimens in children with steroid-sensitive nephrotic syndrome (SSNS). The benefits and harms of therapy were studied in two groups of children 1) children in their initial episode of SSNS, and 2) children who experience a relapsing course of SSNS.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 30 May 2020 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) performed in children (one to 18 years) in their initial or subsequent episode of SSNS, comparing different durations, total doses or other dose strategies using any corticosteroid agent.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data. Results were expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

In this 2020 review update 16 new included studies were identified providing a total of 48 included studies with 3941 randomised participants. Risk of bias methodology was often poorly performed with only 25 studies and 22 studies respectively assessed to be at low risk for random sequence generation and allocation concealment. Only nine studies (19%) were at low risk of bias for performance (blinding of participants and personnel) and 11 studies were at low risk of detection bias (blinding of outcome assessment); nine of these studies were placebo-controlled RCTs. Twenty-two studies (fewer than 50%) were at low risk for attrition bias and 23 studies were at low risk for reporting bias (selective outcome reporting). In seven studies, which evaluated children in their initial episode of SSNS and were at low risk of bias for selection bias, there is little or no difference in the number of children with frequent relapses when comparing two months of prednisone with three months or more (RR 0.99, 95% CI 0.82 to 1.19; 585 participants, 4 studies; I2 = 0%) or when comparing three months with five to seven months of therapy (RR 0.99, 95% CI 0.74 to 1.33; 376 participants, 3 studies; I2 = 35%; high certainty evidence). In analyses of eight studies at low risk of selection bias, there is little or no difference in the number of children with any relapse by 12 to 24 months when comparing two months of prednisone with three months or more (RR 0.91, 95% CI 0.78 to 1.06; 637 participants; 5 studies; I2 = 47%) or when comparing three months with five to seven months of therapy (RR 0.88, 95% CI 0.70 to 1.11; 377 participants, 3 studies; I2 = 53%). Little or no difference was noted in adverse effects between the different treatment durations. Among children with relapsing SSNS, two small studies showed that time to remission did not differ between prednisone doses of 1 mg/kg compared with the conventional dose of 2 mg/kg (MD 0.71 days, 95% CI -0.43 to 1.86; 79 participants) and that the total prednisone dose administered was lower (MD -20.60 mg/kg, 95% CI -25.65 to -15.55; 20 participants). Two studies found little or no difference in the number with relapse at six months when comparing dosing by weight with dosing by surface area (RR 1.03, 95% CI 0.71 to 1.49; 146 participants). One study found a reduced risk of relapse with low daily dosing compared with alternate daily dosing (MD -0.90 number of relapses/year, 95% CI -1.33 to -0.47). Four studies found that in children with frequently relapsing disease, daily prednisone during viral infections compared with alternate-day prednisone or no treatment reduced the risk of relapse.

AUTHORS' CONCLUSIONS

There are now four well designed studies randomising 823 children which have clearly demonstrated that there is no benefit of prolonging prednisone therapy beyond two to three months in the first episode of SSNS. Small studies in children with relapsing disease have identified no differences in the times to remission using half the conventional induction dose of 2 mg/kg or 60 mg/m2. It is imperative that a much larger study be carried out to confirm these findings. Lower dose prednisone therapy administered daily during an upper respiratory infection or other infection reduces the risk of relapse compared with continuing alternate-day prednisone or no prednisone based on four small studies. The results of a much larger RCT enrolling more than 300 children are awaited to determine the relative efficacies and adverse effects of using alternate-day compared with daily prednisone to prevent relapse in children with intercurrent infections.

Risk of fracture according to glucocorticoid use after renal biopsy: a nationwide population-based study

Few data are available regarding fracture risk in patients treated with glucocorticoids, including patients with kidney disease. A population-based retrospective cohort study was performed using Health Insurance Review and Assessment Service database, a South Korean nationwide cohort set. This study identified 44,702 patients with diagnosis code of kidney diseases who received a renal biopsy between January 1, 2012 and December 31, 2017. A total of 8,624 patients met all study inclusion criteria. A total of 1,406 fractures of any site were observed in the study period. The glucocorticoid-exposed group had more fractures than the unexposed (14.4% vs 8.8%, P < 0.0001). Vertebral fractures were the most common, followed by upper limb, and lower limb fractures. The exposed group showed a remarkably higher hazard ratio of fracture risk (HR 6.0, 95% CI 5.01-7.23) than the unexposed group, indicating systemic glucocorticoid exposure was highly associated with fracture risk. Although HR increased at doses even less than 5 mg/day, it was independent of dose. Older age showed a significant effect on fracture risk (HR 1.2, 95% CI 1.05-1.44), even after adjusting for systemic glucocorticoid exposure. Glucocorticoids was associated with higher risk of fracture even at a low daily dose and short term exposure.

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.

Design, Synthesis, and Renal Targeting of Methylprednisolone-Lysozyme

Methylprednisolone (MP) is often used in the treatment of various kidney diseases, but overcoming the systemic side effects caused by its nonspecific distribution in the body is a challenge. This article reports the design, synthesis, and renal targeting of methylprednisolone–lysozyme (MPS–LZM). This conjugate was obtained by covalently linking MP with the renal targeting carrier LZM through a linker containing an ester bond, which could utilize the renal targeting of LZM to deliver MP to renal proximal tubular epithelial cells and effectively release MP. The reaction conditions for the preparation of the conjugate were mild, and the quality was controllable. The number of drug payloads per LZM was 1.1. Cell-level studies have demonstrated the safety and endocytosis of the conjugate. Further pharmacokinetic experiments confirmed that, compared with that of free MP, the conjugate increased the renal exposure (AUC_0–t) of active MP from 17.59 to 242.18 h*ng/mL, and the targeting efficiency improved by approximately 14 times. Tissue and organ imaging further revealed that the conjugate could reach the kidneys quickly, and fluorescence could be detected in the kidneys for up to 12 h. This study preliminarily validates the feasibility of a renal targeting design strategy for MPS–LZM, which is expected to provide a new option for improving kidney-specific distribution of glucocorticoids.

The impact of steroids on the injured podocytes in nephrotic syndrome

Nephrotic syndrome (NS), a common chronic kidney disease, embraces a variety of kidney disorders. Though Glucocorticoids (GCs) are generally used in the treatment of NS, their mechanism of action is poorly understood. A plethora of evidence indicates that podocytes are considered as the main target cells for the therapeutic strategies to prevent NS. GCs regulate the transactivation and transrepression of genes in podocytes that affect their morphological and cytoskeletal features, motility, apoptosis and survival rate. Moreover, they prevent protein leakage through the glomerular barrier membrane by affecting the synthesis, trafficking and posttranslational modifications of slit diaphragms components, podocytes' intercellular junctions. The response to the treatment is variable among different ethnics and populations and resistance to the steroids is detected in almost 50% of adult patients. Not only do pharmacokinetics and pharmacogenetics of steroids play a role in GC resistance but also the genetic variations in one or more podocyte related genes are connected with the steroid resistance in cases with NS. The focus of this review is to explain the underlying cellular and molecular mechanisms of GCs in podocytes. Understanding the mechanisms by which the GCs and GCs receptors in podocytes regulate the gene expression network and crosstalk with other molecular pathways would guarantee an optimum therapeutic benefit of steroid treatment.

Anti-proteinuria effect of antibody against ANGPTL3 coil-coiled domain on adriamycin-induced nephropathy in mice

Proteinuria is an important marker and is closely related to the progressive decline of renal function. Our previous research showed that angiopoietin-like-3 (ANGPTL3) plays a crucial role in proteinuria. In this study, we prepared an antibody against ANGPTL3 coil-coiled domain (ANGPTL3-CCD) and investigated the protective effect of anti-ANGPTL3-CCD antibody in mice with adriamycin-induced nephropathy. Nephropathy was established by adriamycin injection at a dose of 25 mg per kg in 8-12 week-old male mice in the ADR group. Blockade of ANGPTL3 by anti-ANGPTL3-CCD antibody (20 mg per kg) was performed every three days nine times after adriamycin injection in the ADR plus anti-angptl3-antibody group. The anti-ANGPTL3-CCD antibody can specifically recognize ANGPTL3. After anti-ANGPTL3-CCD antibody intervention, the urinary protein level in the ADR plus anti-angptl3-antibody group was significantly lower than that in the ADR group. Serum albumin was higher and triglyceride and total cholesterol were lower in the ADR plus anti-angptl3-antibody group than in the ADR group. The levels of serum creatinine did not significantly differ among the groups. Focal sclerotic glomeruli and podocyte foot processes extensive fusion were found in the renal tissue of the ADR group, whereas no sclerotic glomeruli and only partial fusion were found in the ADR plus anti-angptl3-antibody group. This study demonstrated that the anti-ANGPTL3-CCD antibody ameliorated proteinuria and podocyte dysfunction in adriamycin-induced nephropathy in mice.

Employing Macrophage-Derived Microvesicle for Kidney-Targeted Delivery of Dexamethasone: An Efficient Therapeutic Strategy against Renal Inflammation and Fibrosis

Although glucocorticoids are the mainstays in the treatment of renal diseases for decades, the dose dependent side effects have largely restricted their clinical use. Microvesicles (MVs) are small lipid-based membrane-bound particles generated by virtually all cells. Here we show that RAW 264.7 macrophage cell-derived MVs can be used as vectors to deliver dexamethasone (named as MV-DEX) targeting the inflamed kidney efficiently. Methods: RAW macrophages were incubated with dexamethasone and then MV-DEX was isolated from the supernatants by centrifugation method. Nanoparticle tracking analysis, transmission electron microscopy, western blot and high-performance liquid chromatography were used to analyze the properties of MV-DEX. The LC-MS/MS was applied to investigate the protein compositions of MV-DEX. Based on the murine models of LPS- or Adriamycin (ADR)-induced nephropathy or in-vitro culture of glomerular endothelial cells, the inflammation-targeting characteristics and the therapeutic efficacy of MV-DEX was examined. Finally, we assessed the side effects of chronic glucocorticoid therapy in MV-DEX-treated mice. Results: Proteomic analysis revealed distinct integrin expression patterns on the MV-DEX surface, in which the integrin α_Lβ₂ (LFA-1) and α₄β₁ (VAL-4) enabled them to adhere to the inflamed kidney. Compared to free DEX treatment, equimolar doses of MV-DEX significantly attenuated renal injury with an enhanced therapeutic efficacy against renal inflammation and fibrosis in murine models of LPS- or ADR-induced nephropathy. In vitro, MV-DEX with about one-fifth of the doses of free DEX achieved significant anti-inflammatory efficacy by inhibiting NF-κB activity. Mechanistically, MV-DEX could package and deliver glucocorticoid receptors to renal cells, thereby, increasing cellular levels of the receptor and improving cell sensitivity to glucocorticoids. Notably, delivering DEX in MVs significantly reduced the side effects of chronic glucocorticoid therapy (e.g., hyperglycemia, suppression of HPA axis). Conclusion: In summary, macrophage-derived MVs efficiently deliver DEX into the inflamed kidney and exhibit a superior capacity to suppress renal inflammation and fibrosis without apparent glucocorticoid adverse effects. Our findings demonstrate the effectiveness and security of a novel drug delivery strategy with promising clinical applications.

Idiopathic Retroperitoneal Fibrosis: Long-term Risk and Predictors of Relapse

RATIONALE & OBJECTIVE

Idiopathic retroperitoneal fibrosis (IRF) is a rare disorder of unknown cause. Medical therapy can induce remission, but disease relapses are common. This study sought to characterize long-term outcomes of IRF and the factors associated with disease recurrences.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Retrospective analysis of 50 patients with IRF prospectively followed up for 8.9 (IQR, 4.7-12.7) years at a tertiary-care referral center.

EXPOSURES

Demographic, clinical, treatment, and laboratory parameters, including measures of autoimmunity.

OUTCOME

Disease relapse.

ANALYTICAL APPROACH

Proportional hazards analysis for the subdistribution of competing risks.

RESULTS

49 patients received medical treatment and 35 underwent interventional procedures. All patients experienced a clinical response (defined as regression of disease-related symptoms and hydronephrosis, and decrease in the maximal transverse diameter of the retroperitoneal mass on computed tomography of >50%), 44 of whom responded within 1 year. The remaining 6 responded over a median of 2.95 years after starting therapy. 40 patients were alive at last observation, 1 receiving maintenance dialysis and 15 with estimated glomerular filtration rate < 60mL/min/1.73m². Patient survival at 5, 10, and 15 years was 95%, 84%, and 68%, respectively. 19 (38%) patients had at least 1 relapse (occurring a median of 5.19 years after starting therapy), defined as an increase in serum creatinine level of at least 30% or recurrence/development of hydronephrosis and ≥20% increase in the maximal transverse diameter of the retroperitoneal mass on computed tomography. Cumulative incidences of relapse at 5, 10, and 15 years were 21%, 41%, and 48%, respectively. Baseline antinuclear antibody positivity and male sex were associated with relapse (subdistribution hazard ratios [sHRs] of 5.35 [95% CI, 2.15-13.27] and 4.94 [95% CI, 1.32-18.57], respectively), while higher corticosteroid therapy dosage at 1 year (sHR for relapse per 1-mg/d greater dosage, 0.91 [95% CI, 0.84-0.98]) and treatment with prednisone alone or with tamoxifen (sHR for relapse of 0.25 [95% CI, 0.07-0.85] vs other therapies) were associated with lower rate of relapse.

LIMITATIONS

Small sample size and variable approaches to therapy.

CONCLUSIONS

IRF relapses were common and were experienced more frequently by male patients. Corticosteroids alone or with tamoxifen were associated with a lower rate of relapse. The strong association of antinuclear antibody positivity with relapse supports the hypothesis of an autoimmune pathogenesis of IRF.

Role of the glucocorticoid receptor in glomerular disease

Glucocorticoids are potent anti-inflammatory agents that are commonly used in the treatment of various glomerular diseases. Data from in vitro and in vivo studies, in both animals and humans, convincingly demonstrate that glucocorticoids have many beneficial direct effects on glomeruli, including podocytes, suggesting that, in theory, systemic administration is not necessary to achieve therapeutic benefit. Indeed, it is increasingly recognized that systemic steroids often have an unfavorable risk-to-benefit ratio. As we move into an age of personalized medicine, strategies to develop targeted steroid delivery systems and individualized risk assessment algorithms are desirable in clinicians' efforts to "first, do no harm."

Prevention of complications from use of conventional immunosuppressants: a critical review

Synthetic immunosuppressive drugs are largely used in immune-related renal diseases and in kidney transplantation. Most of these drugs have a low therapeutic index (the ratio that compares the blood concentration at which a drug becomes toxic and the concentration at which the drug is effective), which means that the drug should be dosed carefully and the patient monitored frequently. In this review, we consider the categories of synthetic immunosuppressive agents more frequently and conventionally used in clinical nephrology: glucocorticoids, Aalkylating agents (cyclophosphamide, chlorambucil), purine synthesis inhibitors (azathioprine, mycophenolate salts) and calcineurin inhibitors (cyclosporine, tacrolimus). For each category the possible side effects will be reviewed, the general and specific measures to prevent or treat the adverse events will be suggested, and the more common mistakes that may increase the risk of toxicity will be described. However, the efficacy and safety of immunosuppressive agents depend not only on the pharmacologic characteristics of single drugs but can be influenced also by the clinical condition and genetic characteristics of the patient, by the typology and severity of the underlying disease and by the interaction with other concomitantly used drugs.

Emerging immunotherapies for autoimmune kidney disease

Autoimmunity is a leading cause of chronic kidney disease and loss of native and transplanted kidneys. Conventional immunosuppressive therapies can be effective but are non-specific, noncurative, and risk serious side effects such as life-threatening infection and cancer. Novel therapies and targeted interventions are urgently needed. In this brief review we explore diverse strategies currently in development and under consideration to interrupt underlying disease mechanisms in immune-mediated renal injury. Because autoantibodies are prominent in diagnosis and pathogenesis in multiple human glomerulopathies, we highlight several promising therapies that interfere with functions of early mediators (IgG and complement) of the effector arm and with an epicenter (the germinal center) for induction of humoral immunity.

Proteinuric Kidney Diseases: A Podocyte's Slit Diaphragm and Cytoskeleton Approach

Proteinuric kidney diseases are a group of disorders with diverse pathological mechanisms associated with significant losses of protein in the urine. The glomerular filtration barrier (GFB), comprised of the three important layers, the fenestrated glomerular endothelium, the glomerular basement membrane (GBM), and the podocyte, dictates that disruption of any one of these structures should lead to proteinuric disease. Podocytes, in particular, have long been considered as the final gatekeeper of the GFB. This specialized visceral epithelial cell contains a complex framework of cytoskeletons forming foot processes and mediate important cell signaling to maintain podocyte health. In this review, we will focus on slit diaphragm proteins such as nephrin, podocin, TRPC6/5, as well as cytoskeletal proteins Rho/small GTPases and synaptopodin and their respective roles in participating in the pathogenesis of proteinuric kidney diseases. Furthermore, we will summarize the potential therapeutic options targeting the podocyte to treat this group of kidney diseases.

Induction Therapy for Lupus Nephritis: the Highlights

PURPOSE OF REVIEW

Lupus nephritis is a frequent complication of systemic lupus erythematosus and is more common and severe in children. This is a disease of the immune system characterized by T cell, B cell, and complement activation, as well as immune complex formation and deposition. The introduction of steroids and later cyclophosphamide transformed lupus nephritis from a fatal to a treatable condition. However, the standard therapies currently used for treatment carry significant toxicity and chronic kidney disease still remains a far too frequent outcome. To address these issues, we will review current and emerging induction therapies in LN.

RECENT FINDINGS

Several clinical trials have been undertaken to test more effective and safer drugs, often targeting mechanistic disease pathways. At present, it is difficult to identify an induction regimen that is more effective and less toxic than the standard of care; however, we believe continuing efforts in drug development will bring breakthrough agents to clinics.

Morphometric changes and AQP2 expression in kidneys of young male rats exposed to chronic stress and a high-sucrose diet

OBJECTIVE

Consumption of a cafeteria-like diet and chronic stress have a negative impact on kidney function and morphology in adult rats. However, the interaction between chronic restraint stress and high-sucrose diet on renal morphology in young rats is unknown. A high-sucrose diet does not modify serum glucose levels but reduces serum corticosterone levels in stressed young rats, in this way it is confusing a possible potentiate or protector effect of this diet on kidney damage induced by stress.

METHODS

Wistar male rats at 4 weeks of age were randomly assigned into 4 groups: control (C), stressed (St), high-sucrose diet (S30), and chronic restraint stress plus a 30% sucrose diet (St + S30). Rats were fed with a standard chow and tap water (C group) or 30% sucrose diluted in water (S30 group). Chronic restraint stress consisted of 1-h daily placement into a plastic cylinder, 5 days per week, and for 4 weeks.

RESULTS

Stressed rats exhibited a low number of corpuscles, glomeruli, high number of mesangial cells, major deposition of mesangial matrix and aquaporin-2 protein (AQP-2) expression, and low creatinine levels. Meanwhile, high-sucrose diet ameliorated AQP-2 expression and avoided the reduction of creatinine levels induced by chronic stress. The combination of stress and high-sucrose diet maintained similar effects on the kidney as stress alone, although it induced a greater reduction in the area of proximal tubules.

CONCLUSIONS

Our results show that both chronic stress and a high-sucrose diet induce histological changes, but chronic stress may generate an accelerated glomerular hypertrophy associated with functional changes before puberty.