Elsevier

International Immunopharmacology

Volume 8, Issue 9, September 2008, Pages 1183-1189
International Immunopharmacology

Evaluation of the ameliorative effects of immunosuppressants on crescentic glomerulonephritis in SCG/Kj mice

https://doi.org/10.1016/j.intimp.2008.04.005Get rights and content

Abstract

The therapeutic efficacy of immunosuppressants for treating rapidly progressive glomerulonephritis (RPGN) with crescent formation remains controversial. SCG/Kj mice spontaneously develop RPGN-like symptoms, characteristic of crescentic glomerulonephritis and systemic small vessel vasculitis, associated with the presence of anti-neutrophil cytoplasmic antibodies (ANCA). We evaluated the “ameliorative”, not prophylactic, effects of immunosuppressive agents, deoxyspergualin (DSG), cyclophosphamide (CYC) and prednisolone (PDN), on RPGN in these mice. DSG at intraperitoneal doses of 3 and 6 mg/kg, CYC at an oral dose of 12 mg/kg, or PDN at an intraperitoneal dose of 120 mg/kg was administered once a day for 21 days to female mice “at the onset of hematuria”. A set of control SCG/Kj mice received only saline injections. DSG and CYC significantly prolonged survival, improved the proteinuria, hematuria and hyperuremia, and decreased the serum level of myeloperoxidase-ANCA. Moreover, DSG significantly suppressed the formation of crescents in glomeruli. PDN failed to affect any of the parameters. DSG might be useful for inducing remission in crescentic glomerulonephritis involved in RPGN.

Introduction

Primary systemic vasculitides of small vessels including Wegener's granulomatosis (WG), microscopic polyangiitis and Churg–Strauss syndrome are characterized by rapidly progressive glomerulonephritis (RPGN) and also the presence of anti-neutrophil cytoplasmic antibodies (ANCA) in a highly frequency [1]. Renal glomeruli in patients with these diseases often show crescent and/or granulomatous lesions. In the early 1970s, these vasculitides, which are potentially life-threatening, were reduced to chronic disorders by introducing a treatment regimen based on cyclophosphamide (CYC) combined with corticosteroids, and this treatment regimen has been the standard [2]. The application of CYC, however, causes hemorrhagic cystitis and increases the risk of secondary cancer, gonadotoxicity and severe infection [3].

An immunosuppressive agent, deoxyspergualin (DSG) [4] has been used in rescuing rejection crisis in renal transplant patients in Japan [5]. DSG is an analogue of spergualin [6] isolated from culture filtrate of Bacillus laterosporus, and bears a moiety of spermidine and a guanidinic group. DSG has been found to suppress humoral and cell-mediated immune responses [7], [8], [9], [10], [11], [12], [13]. Although the mechanism behind the DSG-mediated immunosuppression is still not unraveled, it is known that DSG binds to a member of the heat shock protein 70 family and may inhibit the translocation of nuclear factor NF-κB and the expression of MHC class II antigens [14], [15], [16], [17]. DSG has the ability to induce apoptosis in growing cells due to a modification of mitochondrial respiratory function and the down-regulation of Akt kinase and p70 S6 kinase [18], [19], [20]. Regarding patients with RPGN, in 1999, DSG was first administered to four patients with proliferative GN having crescents and thereafter the proteinuria in these patients improved [21]. In 2003, Birck et al. reported that DSG was also effective and well-tolerated in 20 patients with refractory Wegener's granulomatosis uncontrolled by prior treatment with CYC and other immunosuppressive drugs [22]. These findings may provide new insight into the treatment of RPGN, but there are still few therapeutic trials of DSG in these diseases.

In the present study, we evaluated the “ameliorative”, not prophylactic, effects of DSG, in comparison with those of CYC and prednisolone (PDN), on renal disorders in SCG/Kj mice [23]. Females of this strain spontaneously develop crescentic glomerulonephritis (CGN) and systemic vasculitis of small vessels, which was genetically segregated from (BXSB × MRL/lpr) F1 mice of brother × sister matings coupled with the repeated histopathological selection for the breeding of mice whose parents had severe CGN. Moreover, ANCA were detected in almost all of the mice [24]. These mice showed hematuria and proteinuria associated with the formation of crescents in glomeruli at onset, followed by a rapid deterioration of the renal function, resembling RPGN [23], [25]. We herein present the evidence that DSG can efficiently induce a remission of CGN in SCG/Kj mice when administered at the onset of hematuria.

Section snippets

Animals

Female SCG/Kj mice aged 6 to 12 weeks were used in the present study. SCG/Kj mice were bred, maintained under specific pathogen-free conditions, and had free access to food and water during this study in the laboratory of Nippon Kayaku Co., Ltd. This study was conducted according to the principles enunciated in The Guide for the Care and Use of Laboratory Animals prepared b the Laboratory Animal Committee in the Pharmaceuticals Group, Nippon Kayaku Co., Ltd.

Immunosuppressive agents

DSG (Spanidin® for injection; Nippon

Survival time

Survival time was 39% of control, 67% of 3 mg/kg of DSG, 74% of 6 mg/kg of DSG, 70% of CYC and 51% of PDN, respectively (Fig. 2). There was a significant increase in survival times in the SCG/Kj mice given DSG at 6 mg/kg and CYC, compared with the control group. Treatment with DSG at 3 mg/kg slightly (p = 0.063) prolonged survival, and PDN failed to prolong life span.

Urinalysis

At the end of the study, the percentage of SCG/Kj mice with grade ++++ severe proteinuria was 88% of control, 50% of DSG at

Discussion

A hallmark of SCG/Kj mice is extensive extraglomerular proliferation and hemorrhage in Bowman's space (Fig. 1). In a previous study of serial urinalysis and renal biopsies with SCG/Kj mice, it was found that proteinuria initially appeared, followed by hematuria at which time the mice developed prominent crescents in glomeruli [25]. In their histopathological study, neutrophils accumulated into glomeruli in the early stage of glomerular lesions of SKG mice, but not in the late phase, in which

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