Prednisolone can increase glomerular permeability to proteins in nephrotic syndrome

Pharmacological Evaluation of a Pegylated Urocortin-1 Peptide in Experimental Autoimmune Disease Models

Urocortin-1 (UCN1) is a member of the corticotropin releasing hormone (CRH) family of peptides that acts through CRH-receptor 1 (CRHR1) and CRH-receptor 2 (CRHR2). UCN1 can induce adrenocorticotropin hormone (ACTH) and downstream glucocorticoids through CRHR1 and promote beneficial metabolic effects through CRHR2. UCN1 has a short half-life and has been shown to improve experimental autoimmune disease. A pegylated UCN1 peptide (PEG-hUCN1) was generated to extend half-life and was tested in multiple experimental autoimmune disease models and in healthy mice to determine effects on corticosterone induction, autoimmune disease, and glucocorticoid induced adverse effects. Cardiovascular effects were also assessed by telemetry. PEG-hUCN1 demonstrated a dose dependent 4-to-6-fold elevation of serum corticosterone and significantly improved autoimmune disease comparable to prednisolone in several experimental models. In healthy mice, PEG-hUCN1 showed less adverse effects compared to corticosterone treatment. PEG-hUCN1 peptide induced an initial 30% reduction in blood pressure that was followed by a gradual and sustained 30% increase in blood pressure at the highest dose. Additionally, an adeno-associated viral 8 (AAV8) UCN1 was used to assess adverse effects of chronic elevation of UCN1 in wild type and CRHR2 knockout mice. Chronic UCN1 expression by an AAV8 approach in wild type and CRHR2 knockout mice demonstrated an important role of CRHR2 in countering the adverse metabolic effects of elevated corticosterone from UCN1. Our findings demonstrate that PEG-hUCN1 shows profound effects in treating autoimmune disease with an improved safety profile relative to corticosterone and that CRHR2 activity is important in metabolic regulation. Significance Statement This study reports the generation and characterization of a pegylated UCN1 peptide and the role of CRHR2 in UCN1-induced metabolic effects. The potency/selectivity, pharmacokinetic properties, pharmacodynamic effects and efficacy in four autoimmune models and safety profiles are presented. This pegylated UCN1 shows potential for treating autoimmune diseases with reduced adverse effects compared to corticosterone treatment. Continuous exposure to UCN1 through an AAV8 approach demonstrates some glucocorticoid mediated adverse metabolic effects that are exacerbated in the absence of the CRHR2 receptor.

Mitigation of dexamethasone-induced nephrotoxicity by modulating the activity of adrenergic receptors: Implication of Wnt/β-arrestin2/β-catenin pathway

The present study aimed to investigate the role of α and β-adrenergic receptors (βARs) in mediation or modulation of the dexamethasone-induced nephrotoxicity by using different pharmacological interventions. Nephrotoxicity was induced by subcutaneous injection of dexamethasone (10 mg/kg) for 7 days in Wistar albino rats. Eight groups were used: control; dexamethasone; carvedilol; phenylephrine; carvedilol and phenylephrine; propranolol; doxazosin; propranolol and doxazosin. At the end of experiment, rats were euthanized and blood, urine and kidney samples were collected. Serum and urinary creatinine and urinary total protein levels were measured. Also, the renal tissue levels of diacylglycerol (DAG); Akt kinase activity, malondialdehyde (MDA), NADPH oxidase 2 (NOX2), transforming growth factor-β (TGF-β), Wnt3A and β-catenin were recorded. Furthermore, histopathological and β-arrestin2-immunohistochemical examinations of renal tissues were performed. Results: Dexamethasone induced glomerular damage, proteinuria, renal oxidative stress and upregulated the renal Wnt/β-arrestin2/β-catenin pathway and the profibrotic signals. Blocking the α1 and βARs by carvedilol reduced the dexamethasone-induced nephrotoxicity. Pre-injection of phenylephrine did not reduce the reno-protective action of carvedilol. Blocking the βARs only by propranolol reduced the dexamethasone-induced nephrotoxicity to the same extent of carvedilol group. Blocking the α1ARs only by doxazosin reduced dexamethasone-induced nephrotoxicity to a higher extent than other treatments. However, combined use of propranolol and doxazosin did not synergize the reno-protective effects of doxazosin. Conclusion: Dexamethasone induces nephrotoxicity, possibly, by upregulating the Wnt/β-arrestin2/β-catenin pathway. Blocking either α1ARs or βARs can effectively protect against the dexamethasone-induced nephrotoxicity. However, combined blocking of α1ARs and βARs does not synergize the reno-protective effects.

Repeated pulses of methyl-prednisolone with reduced doses of prednisone improve the outcome of class III, IV and V lupus nephritis: An observational comparative study of the Lupus-Cruces and lupus-Bordeaux cohorts

OBJECTIVE

To compare the clinical course of patients with class III, IV and V lupus nephritis (LN) treated at Hospital Universitario Cruces (CC) and at Bordeaux University Hospital (BC).

METHODS

The Lupus-Cruces nephritis protocol combines pulses of 125mg of methyl-prednisolone with each fortnightly pulse of cyclophosphamide and prednisone ≤30mg/day with tapering over 12-14weeks until 2.5-5mg/day. The BC followed international lupus nephritis guidelines, combining high-dose prednisone and either mycophenolate mofetil or cyclophosphamide, followed by maintenance therapy with low dose prednisone and immunosuppressive drugs. The main outcomes were complete renal remission (CR) and glucocorticoid toxicity.

RESULTS

44 patients from BC and 29 from CC were included. The mean maximum prednisone dose was 42.5 (BC) vs. 21mg/day (CC), p<0.001. The average 6-month prednisone dose was 21 (BC) vs. 8.3mg/d (CC), p<0.001.The mean number of methyl-prednisolone pulses was 3 (BC) vs. 9.3 (CC), p<0.001. HCQ was used by 64% (BC) vs. 100% (CC), p<0.001. CR rates were 30% (BC) vs. 69% (CC), p=0.001, and 42% (BC) vs. 86% (CC), p<0.001, at 6 and 12months, respectively. Patients from the CC more frequently achieved CR (adjusted HR 3.8, 95%CI 2.05-7-09). The number of pulses of methyl-prednisolone were associated with CR (adjusted HR 1.09, 95%CI 1.03-1.15). Patients in the CC had a lower risk of GC-related side effects (adjusted HR 0.19, 95%CI 0.04-0.89).

CONCLUSION

The Lupus-Cruces nephritis protocol improves the outcome of LN. Repeated methyl-prednisolone pulses help reduce the dose of oral glucocorticoids and enhance clinical response.

Urine proteomic profiling of pediatric nephrotic syndrome

The prognosis of pediatric nephrotic syndrome (NS) correlates with the responsiveness to glucocorticoid therapy. Steroid-resistant NS (SRNS) patients progress to end-stage renal disease, while steroid-sensitive NS (SSNS) and steroid-dependent (SDNS) patients do not. We have performed proteomic profiling of urine samples from a cross section of pediatric and adolescent subjects with SSNS, SRNS, and orthostatic proteinuria (OP) to identify urinary biomarkers of steroid resistance. We performed surface-enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF MS) on urine from 19 subjects with SSNS/SDNS in remission, 14 with SSNS/SDNS in relapse, 5 with SRNS in relapse, and 6 with OP. Genetic algorithm search of principal component space revealed a group of five peaks distinguishing SRNS subjects, with mass/charge (m/z) values of 3,917.07, 4,155.53, 6,329.68, 7,036.96, and 11,117.4. Our analyses identified the peak at m/z 11,117.4 with an accuracy of 95% for classifying SRNS. Multidimensional protein fractionation and mass spectrometric analysis of SRNS urine samples combined with immunodepletion identified the 11,117.4 protein as beta2-microglobulin (B2M). Using an unbiased protein profiling approach, we have validated previously reported findings of B2M as a biomarker associated with SRNS. Prospective studies are warranted to establish additional biomarkers that would be predictive of SRNS.

Glucocorticoid diminishes vascular endothelial growth factor and exacerbates proteinuria in rats with mesangial proliferative glomerulonephritis

Glucocorticoids are widely prescribed for renal diseases. It is believed that glucocorticoids attenuate immune-mediated renal diseases by suppressing the cell-mediated immune system. However, there is evidence that glucocorticoids influence the expression of such growth factors as vascular endothelial growth factor (VEGF), transforming growth factor-beta1 (TGF-beta1), and connective tissue growth factor (CTGF), which are known to influence the development or progression of renal diseases. Therefore, we undertook this study to determine whether glucocorticoids regulate proteinuria or extracellular matrix (ECM) production by altering these growth factors. Mesangial proliferative glomerulonephritis was induced in rats by intravenous injection of monoclonal antibody (OX-7), and dexamethasone (20 mg/kg) was administered intraperitoneally from the third to seventh disease day. Glomerular expression of VEGF, TGF-beta1, and CTGF, the amount of urinary protein, and glomerular ECM were measured on the seventh disease day. The nephritic group showed proteinuria and greater VEGF, TGF-beta1, and ECM production. Dexamethasone aggravated proteinuria (protein, 0.4 +/- 0.1 mg/mg creatinine in the NC group, 6.3 +/- 2.0 mg/mg creatinine in the DC group, and 21.1 +/- 1.9 mg/mg creatinine in the D-Dex group; P < 0.05) and diminished VEGF release (22 +/- 3 pg/mg total protein in the NC group, 292 +/- 26 pg/mg total protein in the DC group, and 198 +/- 23 pg/mg total protein in the D-Dex group; P < 0.05). Expression of TGF-beta1, CTGF, and ECM was not altered significantly by dexamethasone treatment. We found that glucocorticoid diminishes VEGF release and at the same time exacerbates proteinuria in rats with this type of glomerulonephritis.

Glucocorticoid activates glomerular antioxidant enzymes and protects glomeruli from oxidant injuries

We examined the effect of glucocorticoid on intrinsic glomerular antioxidant enzyme (AOE) activities. Munich-Wistar rats were treated with daily i.p. injection of vehicle or methylprednisolone [MP, 15 mg/kg body wt, (MP15)] either for three days or nine days. Glomeruli isolated from rats given MP15 had significantly higher activities of total (T-) and manganese (Mn-) superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase than vehicle-treated rats (P less than 0.05). MP15-treated rats were subjected to intrarenal arterial infusion of hydrogen peroxide (35 mumol over 1 hr). Values for urinary protein excretion rate (UprV) after hydrogen peroxide infusion were markedly lower in rats pretreated with MP15 for both three days and nine days than in untreated rats (109 +/- 18 and 55 +/- 24 vs. 416 +/- 73 micrograms/min, respectively, both P less than 0.005). To test whether the same therapeutic intervention attenuates reactive oxygen species (ROS)-mediated glomerular injury in another model, rats given a single i.v. dose of puromycin aminonucleoside (PAN) (50 mg/kg body wt) were treated with daily i.p. injection of vehicle or MP15. Two days after PAN administration, when compared to vehicle-treated controls, PAN rats given MP15 had significantly higher activities of Mn-SOD, GSH-Px and catalase. After eight days of PAN injection, T- and Mn-SOD activities were, likewise, significantly higher in MP15- than vehicle-treated PAN rats. PAN rats given MP15 also had substantially less proteinuria, compared to PAN rats given vehicle alone, UprV averaging 32.3 +/- 9.4 versus 159.0 +/- 13.8 mg/24 hr (P less than 0.05). Elevated glomerular malondialdehyde (MDA) level characteristic of PAN rats was absent in rats treated with MP15. Moreover, epithelial foot process fusion and cell vacuolization seen in vehicle-treated PAN rats were markedly attenuated in MP15-treated PAN rats. These data indicate that the mechanism for therapeutic effect of glucocorticoids on ROS-mediated renal injuries includes an enhancement of endogenous glomerular AOE activities, which attenuates lipid peroxidation of glomerular tissue.