First-line Combination Strategy Provides Favorable 5-year Outcomes for Patients with Lupus Nephritis: A Single-center Observational Study

This observational study aimed to clarify the long-term results of the combination of mizoribine (MZB), tacrolimus (TAC) and prednisolone as first-line therapy for lupus nephritis (LN). This was our institution's standard therapy between 2009 and 2015, when we saw 36 patients with LN. When a patient thus treated achieved SLEDAI remission (= 0) and/or the prednisolone dose could be tapered to 5 mg/day, either MZB or TAC was stopped, and the other was continued for maintenance therapy. If treatment failure or relapse occurred, second-line therapy was introduced. At years 1 and 5, overall complete renal response and SLEDAI remission were 94% and 88%, and 50% and 62%, respectively. Excluding 2 cases lost to follow-up, medications after 5 years were as follows: 20 (59%) were stable on 1 drug (MZB or TAC), 11 (32%) required continuation of both drugs (MZB + TAC), and 3 (9%) required second-line therapy. The 5-year retention rate was 91% (non-secondline), with 0% of relapse in this group. Our first-line combination strategy showed high remission rates in the induction phase, and subsequent maintenance therapy demonstrated good outcomes for up to 5 years. Research that fine-tunes the order of therapeutic agents and institutes appropriate treatment goals may further improve long-term outcomes for patients with LN.

Comparative efficacy and safety of mizoribine and mycophenolate mofetil for treating systemic lupus erythematosus: a retrospective cohort study

Background

Mizoribine (MZR) is an immunosuppressive agent that selectively inhibits inosine monophosphate dehydrogenase; its actions are considerably similar to those of mycophenolate mofetil (MMF). This study aimed to clarify whether MZR can be a good treatment option for systemic lupus erythematosus (SLE) and to compare the efficacy and safety of MZR and MMF in patients with active SLE.

Methods

We retrospectively compared the efficacy, continuation rate, and safety of MZR (52 patients) and MMF (31 patients) after adjusting for stabilized inverse probability of treatment weighting based on propensity scores. The efficacy endpoints were as follows: cumulative incidence of lupus low disease activity state (LLDAS) or remission attainment and flares and change in prednisolone dose over 2 years. Drug continuation rates were defined as the time from drug initiation to discontinuation for any cause, owing to the lack of efficacy, or owing to adverse events. The safety endpoint was the frequency of adverse events.

Results

Overall, 25 (48.1%) and 13 (25.0%) patients in the MZR group and 18 (58.1%) and 15 (48.3%) in the MMF group achieved LLDAS and remission during the follow-up period, respectively; thus, the cumulative incidence of LLDAS and remission attainment of the two groups was similar after adjustment. Prednisolone dose was steadily reduced in both the groups, and the change in prednisolone dose was nearly identical between the two groups. Drug discontinuation rate due to adverse events and the frequency of all adverse events and infections were higher in the MMF group than in the MZR group, albeit without significance after adjustment.

Conclusion

MZR is as effective as MMF in controlling SLE activity. The adverse events of MZR, whose profile differs from MMF, are comparable to or less than those of MMF. MZR may be a valuable option as an immunosuppressive agent for SLE, as well as MMF.

Effectiveness and safety of Mizoribine for the treatment of IgG4-related Disease: A Retrospective Cohort Study

OBJECTIVE

Patients with IgG4-Related Disease (IgG4RD) usually require steroid-sparing agents due to relapse with tapering glucocorticoids (GC). The aim of this study was to determine the efficacy and safety of Mizoribine (MZR) among IgG4RD, which inhibits inosine monophosphate dehydrogenase, a rate-limiting enzyme in the de novo pathway of purine synthesis.

METHODS

We retrospectively reviewed records of IgG4RD patients at the Immuno-Rheumatology Center in St. Luke's International Hospital, Tokyo, Japan. Patients were classified into the MZR combination group, and those treated with GCs alone or with other immunosuppressants were included in the control group. Disease exacerbation, GC dose, IgG-IgG4 titre, and adverse events were evaluated using univariate analyses, including the Kaplan-Meier method. The Cox proportional hazard model was used to evaluate risk factors for exacerbation.

RESULTS

A total of 14 and 29 cases were included in the MZR combination and control groups, respectively. Multiple organ involvement (≥3 organs) was significantly more frequent in the MZR combination treatment group (10 [71.4%] vs 9 [31.0%], p= 0.021). Kaplan-Meier analysis revealed a significant reduction in exacerbation in patients with multiple organ involvement (p< 0.001), but not in total (p= 0.42). The adjusted hazard ratios of MZR use and multiple organ involvement for exacerbation were 0.34[0.12-1.01] (p= 0.052), and 3.51[1.29-9.51] (p= 0.014). The cumulative GC dose tended to be lower in the MZR combination group (1448[1003, 1642] vs 2179[1264, 3425]; p= 0.09).

CONCLUSION

MZR showed a significant steroid-sparing effect and decrease in exacerbation among IgG4RD patients with multi-organ involvement. MZR could be a treatment option for IgG4RD.

Comparison of Treatment Effect and Tolerance of the Topical Application of Mizoribine and Cyclosporine A in a Mouse Dry Eye Model

Purpose

To compare the treatment effects and tolerability of a topical application of mizoribine (MZR) and cyclosporine A (CsA) eye drops (Restasis; Allergan, Inc., Irvine, CA, USA) in a mouse dry eye model.

Methods

C57BL/6 mice subjected to desiccating stress (DS) were treated with 0.05% MZR in phosphate-buffered saline (PBS) or Restasis eye drops four times a day for 5 days. Untreated mice served as control. Tear secretion, Oregon green dextran staining, and the conjunctival goblet cell quantity were evaluated. The apoptosis and matrix metalloproteinase 9 (MMP-9) in the ocular surface, conjunctival CD4, and T helper–related cytokines were verified. The ocular tolerance of these two drugs was evaluated by observing the mice's behavioral changes.

Results

Topical administrations of MZR or Restasis both increased tear production, maintained goblet cell density, and improved corneal barrier function. Both MZR and Restasis suppressed the expression of MMP-9 and apoptosis in the ocular surface. Meanwhile, both MZR and Restasis decreased the infiltration of CD4⁺ T cells, reversed the production of interferon-γ, interleukin (IL)–17A, and IL-13 in conjunctiva under DS. The abovementioned efficacies between these two eye drops were not statistically significant. However, the number of scratching and wiping behaviors in the MZR-treated group was significantly less than in the Restasis-treated group.

Conclusions

MZR (0.05% in PBS) could be a good competitive product for Restasis because of the comparable treatment effect in dry eye diseases and better ocular tolerability in ocular itch and pain.

Translational Relevance

This study provided an immunosuppressive agent comparable to Restasis for the treatment of dry eye disease.

Mizoribine treatment in an elderly diabetic patient with antisynthetase-associated interstitial lung disease

Objective: Immunosuppressive therapy for interstitial lung disease (ILD) is often necessary, but the standard regimen for antisynthetase-associated ILD has not been established.

Patient: An 80-year-old man was hospitalized for severely progressive dyspnea. Bilateral interstitial shadows occurred 1 month before the event. Serological findings showed that he had antisynthetase-associated ILD, as identified by strong positivity for anti-aminoacyl-transfer RNA synthetase (ARS) antibody, despite no evidence of myositis. He was treated transiently with noninvasive positive pressure ventilation and steroid-pulse therapy followed by 60 mg/day of oral prednisolone. However, his diabetes mellitus was aggravated by corticosteroid therapy; thus, a combination of low-dose steroid and mizoribine (MZB), which has a low risk of aggravating glucose intolerance, was used.

Results: The patient’s clinical symptoms and daily life activities have been well persevered as an outpatient and well maintained with 200 mg of MZB and 10 mg of prednisolone for several months without obvious clinical recurrence and without any remarkable steroid- and MZB-related side effects.

Conclusion: The use of MZB appeared to suppress the pathophysiology of anti-ARS antibody-associated ILD.

COVID-19 and hypertension: is the HSP60 culprit for the severe course and worse outcome?

The 60-kDa heat shock protein (HSP60) is a chaperone essential for mitochondrial proteostasis ensuring thus sufficient aerobic energy production. In pathological conditions, HSP60 can be translocated from the mitochondria and excreted from the cell. In turn, the extracellular HSP60 has a strong ability to trigger and enhance inflammatory response with marked proinflammatory cytokine induction, which is mainly mediated by Toll-like receptor binding. Previous studies have found increased circulating levels of HSP60 in hypertensive patients, as well as enhanced HSP60 expression and membrane translocation in the hypertrophic myocardium. These observations are of particular interest, since they could provide a possible pathophysiological explanation of the severe course and worse outcome of severe acute respiratory syndrome coronavirus 2 infection in hypertensive patients, repeatedly reported during the recent coronavirus disease 2019 (COVID-19) pandemic and related to hyperinflammatory response and cytokine storm development during the third phase of the disease. In this regard, pharmacological inhibition of HSP60 could attract attention to potentially ameliorate inappropriate inflammatory reaction in severe COVID-19 patients. Among HSP60 antagonizing drugs, mizoribine is the most intriguing, since it is clinically approved and exerts antiviral activity. However, this topic requires to be further scrutinized.

In Vitro and in Vivo Antiviral Activity of Mizoribine Against Foot-And-Mouth Disease Virus

Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals, which has significant economic consequences in affected countries. As the currently available vaccines against FMD provide no protection until 4–7 days post-vaccination, the only alternative method to control the spread of FMD virus (FMDV) during outbreaks is the application of antiviral agents. Hence, it is important to identify effective antiviral agents against FMDV infection. In this study, we found that mizoribine has potent antiviral activity against FMDV replication in IBRS-2 cells. A time-of-drug-addition assay demonstrated that mizoribine functions at the early stage of replication. Moreover, mizoribine also showed antiviral effect on FMDV in vivo. In summary, these results revealed that mizoribine could be a potential antiviral drug against FMDV.

Favorable response to immunosuppressive combination therapy with mizoribine and azathioprine in children with primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC), with no curative intervention, can progress to end-stage liver disease. Mizoribine, a purine antimetabolite, has never been used for the management of PSC. To evaluate the role of mizoribine with azathioprine we undertook a preliminary clinical study in children with PSC. Children with PSC and autoimmune features were simultaneously treated with mizoribine and azathioprine. Ursodeoxycholic acid or mesalazine were not regulated. The primary end-points of our study included improvement of aspartate aminotransferase, alanine aminotransferase, and γ-glutamyltransferase. Liver histology, immunostaining studies of the liver, and magnetic resonance cholangiopancreatography (MRCP) were also assessed. We have treated four PSC children: two treatment-naïve patients (cases 1 and 2), and two with established liver cirrhosis (cases 3 and 4). Both case 1 and 2 showed a normalization of liver enzymes and case 2 showed an improvement in MRCP findings. Cases 3 and 4 also showed an improvement in varices, MRCP findings, and liver histology. The combination therapy may be effective for some children with PSC and autoimmune features. By ameliorating both parenchymal inflammation and cholangiopathy of PSC, the therapy might improve the prognosis for patients. It awaits further prospective studies to confirm the efficacy of this therapy in patients with PSC.

Serum IgA/C3 and glomerular C3 staining predict severity of IgA nephropathy

BACKGROUND

The aim of this study was to determine whether serum immunoglobulin A/complement factor 3 (IgA/C3) ratio and glomerular C3 staining predict outcome in IgA nephropathy.

METHODS

We collected data for 44 IgA nephropathy children treated with multi-drug combination therapy. The children were retrospectively divided into four groups based on serum IgA/C3 ratio and glomerular C3 staining: group A, IgA/C3 ratio >2.68 (median) and glomerular C3 staining ≥2.0, n = 9; group B, IgA/C3 ratio >2.68 and glomerular C3 staining <2.0, n = 7; group C, IgA/C3 ratio <2.68 and glomerular C3 staining ≥2.0, n = 7; and group D, IgA/C3 ratio <2.68 and glomerular C3 staining <2.0, n = 21. Clinical features; pathology at the first and second renal biopsy and at the latest follow up; and prognosis were analyzed for the four groups.

RESULTS

At the most recent follow up, urinary protein excretion, incidence of hematuria, and serum creatinine in group A were all higher than in group D. At the second biopsy, crescent absence/presence ratio; mesangial hypercellularity, segmental glomerulosclerosis or adhesion, endocapillary hypercellularity, and tubular atrophy/interstitial fibrosis as well as crescents and global glomerulosclerosis (MESTCG) score; and clonicity index in group A were higher than in group D. All patients in group D had normal urine, and the prevalence of persistent nephropathy in group A was higher than in group D.

CONCLUSIONS

Serum IgA/C3 ratio and glomerular C3 staining can predict outcome in IgA nephropathy.

Mizoribine is as Effective as Methotrexate for the Treatment of Polymyalgia Rheumatica: A Retrospective Case Series Analysis

Objectives

This study aims to evaluate the efficacy and safety of mizoribine (MZR) as a steroid-sparing agent compared to methotrexate (MTX) in the treatment of polymyalgia rheumatica in elderly patients.

Patients and methods

Twenty-four patients (9 males, 15 females; mean age 71.7 years; range 50 to 86 years) diagnosed with polymyalgia rheumatica between April 1998 and August 2014, who received prednisone in combination with either MTX or MZR, were included. We collected the data on the cumulative prednisone dose that patients received within 48 weeks after MTX or MZR and its side effect profile.

Results

There were 10 patients in the MTX group and 14 in the MZR group. The cumulative prednisone dose over 0-48 weeks was 2272±396 mg in the MTX group and 1907±241 mg in the MZR group, which was not significantly different (p=0.41). In terms of side effects, in the MTX group, three patients experienced a transient elevation in liver enzymes, and one patient developed gastrointestinal symptoms that led to MTX withdrawal. In the MZR group, one patient was hospitalized due to pneumonia that led to MZR withdrawal.

Conclusion

Mizoribine was non-inferior to MTX in terms of steroid-sparing effects on polymyalgia rheumatica. Also, MZR tended to have fewer side effects than MTX.

mTORC1 Couples Nucleotide Synthesis to Nucleotide Demand Resulting in a Targetable Metabolic Vulnerability

The mechanistic target of rapamycin complex 1 (mTORC1) supports proliferation through parallel induction of key anabolic processes, including protein, lipid, and nucleotide synthesis. We hypothesized that these processes are coupled to maintain anabolic balance in cells with mTORC1 activation, a common event in human cancers. Loss of the tuberous sclerosis complex (TSC) tumor suppressors results in activation of mTORC1 and development of the tumor syndrome TSC. We find that pharmacological inhibitors of guanylate nucleotide synthesis have selective deleterious effects on TSC-deficient cells, including in mouse tumor models. This effect stems from replication stress and DNA damage caused by mTORC1-driven rRNA synthesis, which renders nucleotide pools limiting. These findings reveal a metabolic vulnerability downstream of mTORC1 triggered by anabolic imbalance.

High-dose mizoribine combined with calcineurin inhibitor (cyclosporine or tacrolimus), basiliximab and corticosteroids for renal transplantation: A Japanese multicenter study

OBJECTIVE

To evaluate the utility and safety of high-dose mizoribine combination therapy using cyclosporine and tacrolimus as calcineurin inhibitors in patients undergoing kidney transplant.

METHODS

The present study enrolled 156 patients who received kidney transplants in 18 institutions between 2009 and 2013. ABO-incompatible and/or pre-sensitized recipients were excluded. Immunosuppression used cyclosporine (88) or tacrolimus (68) as a calcineurin inhibitor, and the dosage was adjusted based on blood concentrations. Mizoribine was started at 6 mg/kg/day, and the target trough level was 1-2 ng/mL. Primary efficacy end-points of this study were 2-year patient survival, 2-year graft survival and the acute rejection rate within 2 years after transplantation.

RESULTS

The 2-year patient and graft survival rates in the cyclosporine group were 98.9% and 94.3%, respectively, whereas those in the tacrolimus group were 100% and 98.5%, respectively, with no significant difference between groups. Rates of onset of rejection during the observation period were also equivalent, at 22.7% in the cyclosporine group and 17.6% in the tacrolimus group. Furthermore, groups showed no significant differences in transplanted renal function. No notable differences in adverse events were observed between groups.

CONCLUSIONS

A regimen of high-dose mizoribine in combination with calcineurin inhibitors basiliximab, and corticosteroids can provide effective immunosuppression while lowering the rate of cytomegalovirus infection in kidney transplant patients.

Membranoproliferative glomerulonephritis associated with Rosai-Dorfman disease

Rosai-Dorfman disease is also known as sinus histiocytosis with massive lymphadenopathy. Extranodal Rosai-Dorfman disease has been reported in ~ 43% of cases; the most frequent extranodal sites – skin, soft tissue, bone, respiratory tract, and eye – are usually involved in association with lymphadenopathy. Lack of lymph node involvement is rare, especially when patients manifest renal disease. Here, we describe a patient who developed membranoproliferative glomerulonephritis when lymphadenopathy was absent. During follow-up for sinus histiocytosis, a 7-year-old Japanese boy developed proteinuria and hematuria. No renal abnormality was present in ultrasound imaging. Histologic examination of a renal biopsy specimen disclosed moderate mesangial proliferation, focal thickening of glomerular capillary walls, and mesangial interposition. Mononuclear cells infiltrated the interstitium. Immunofluorescence showed intense IgG, C3, and C4 reactivity in portions of the mesangium and glomerular capillary walls. Electron microscopy depicted nodular deposits in mesangial, endocapillary, and subepithelial areas. Immunohistochemistry for S-100 protein, CD68, and lysozyme was positive within the interstitium. CD1a staining was absent. These findings were diagnostic for membranoproliferative glomerulonephritis. Multidrug therapy, including methylprednisolone and mizoribine, improved urinary findings and induced complete remission of both diseases. To the best of our knowledge, this is the first report of Rosai-Dorfman disease complicated by renal disease in the absence of concurrent nodal involvement. Clinicians should be alert to this diagnostic possibility.

Post-marketing surveillance study of the long-term use of mizoribine for the treatment of lupus nephritis: 2-Year results

OBJECTIVES

To understand the status of mizoribine use in patients with lupus nephritis (LN) and to collect safety- and efficacy-related data on 2-year treatment with mizoribine.

METHODS

A continuous survey was conducted between March 2010 and July 2015.

RESULTS

The analysis set included 559 patients (mean age 39.5 years, females 82.6%, mean duration of systemic lupus erythematosus (SLE) 8.4 years, mean duration of LN 5.9 years). Renal function was satisfactory for 6 months, but worsened from 12 months, with significant worsening at 24 months. By the ACR 2006 remission criteria (eGFR >60), at 24 months, 26.5% of patients achieved complete remission, and 63.3% achieved complete or partial remission. The urine protein to creatinine ratio decreased significantly. The SLE Disease Activity Index 2000 score decreased significantly at 12 and 24 months. Overall, 98 (17.5%) patients experienced 124 adverse drug reactions (ADRs); 3.6% experienced serious ADRs. Mizoribine was used with a steroid in 99.3% and an immunosuppressant in 51.2%; tacrolimus was used in 43.8%. The oral steroid dosage decreased from baseline to 24 months. The incidence of ADRs was not significantly different with concomitant tacrolimus use.

CONCLUSIONS

The results suggest that long-term mizoribine is safe and effective, even when used with tacrolimus.

Mizoribine Synchronized Methotrexate Therapy should be Considered when Treating Rheumatoid Arthritis Patients with an Inadequate Response to Various Combination Therapies

Objective The objective of this study was to confirm the efficacy of low-dose mizoribine (MZR), an inhibitor of inosine monophosphate dehydrogenase, as part of synchronized methotrexate (MTX) therapy for rheumatoid arthritis (RA) patients with an inadequate response to various combination therapies of MTX, other synthetic disease-modifying anti-rheumatic drugs (DMARDs) and biological DMARDs. Methods Low-dose MZR was administered to 56 uncontrolled RA patients being treated with MTX and various biological DMARDs. The observation period was 12 months, and the disease activity was evaluated based on the Disease Activity Score in 28 joints (DAS28)-ESR, Simplified Disease Activity Index (SDAI) and serum MMP-3 level. Results All of the disease activity indices were significantly improved within three months, and the serum MMP-3 levels were also significantly decreased around four months after starting low-dose MZR therapy. No patients experienced any adverse effects. Conclusion The present preliminary findings suggest that low-dose MZR therapy with MTX should be considered for the treatment of RA patients with an inadequate response to various combination therapies including MTX, other synthetic DMARDs and biological DMARDs or in whom increasing the dose of MTX is difficult for reasons such as adverse effects and complications.

Successful therapy with tonsillectomy plus pulse therapy for the relapse of pediatric IgA nephropathy treated with multi-drugs combination therapy

Immunoglobulin A nephropathy (IgAN) is the most common form of chronic glomerulonephritis worldwide.　In Japan, the treatment for use as an initial therapy was established in Guidelines for the Treatment of Childhood IgA nephropathy; however, no rescue therapy for recurrent or steroid-resistant pediatric IgAN was established.　We report here a 15-year-old boy with severe IgAN, who was treated with combination therapy involving prednisolone, mizoribine, warfarin, and dilazep dihydrochloride for 2 years.　The response to the combination therapy was good and both proteinuria and hematuria disappeared.　The pathological findings at the second renal biopsy were improved and PSL was discontinued.　However, due to nonadherence to the treatment regimen and tonsillitis, macrohematuria and an increase of proteinuria were again observed and the pathological findings at the third renal biopsy showed clear deterioration.　The patient was, therefore, diagnosed with recurrent IgAN.　Tonsillectomy plus methylprednisolone pulse therapy (TMP) was performed as a rescue therapy for the recurrence of severe IgAN.　Both the proteinuria or hematuria subsequently disappeared, and no proteinuria or hematuria has been observed and kidney function has remained normal during a 5-year follow-up.　The patient experienced no severe side effects associated with the drug regimens.　In conclusion, our case suggests that TMP may be an effective and useful rescue therapy for recurrent IgAN after multi-drug combination therapy.

A four-drug combination therapy consisting of low-dose tacrolimus, low-dose mycophenolate mofetil, corticosteroids, and mizoribine in living donor renal transplantation: A randomized study

OBJECTIVE

We compared a three-drug combination therapy (control group) consisting of tacrolimus, mycophenolate mofetil, and corticosteroids in living donor renal transplantation with a four-drug combination therapy (study group), in which the doses of tacrolimus and mycophenolate mofetil were halved and the immunosuppressive drug mizoribine was added, in order to determine whether the incidence rates of acute rejection after transplantation between the study group and the control group are similar, whether the study group regimen prevents the occurrence of calcineurin inhibitor-induced renal damage, and whether the study group regimen prevents adverse effects such as diarrhea caused by mycophenolate mofetil.

METHODS

We investigated the incidence of acute rejection, serum creatinine levels, and estimated glomerular filtration rate and the incidence of adverse effects such as diarrhea.

RESULTS

There was no significant difference between the two groups in the incidence of acute rejection. Renal function (estimated glomerular filtration rate and serum creatinine) was maintained in the control group whereas in the study group renal function gradually improved, with a statistical difference observed at 12 months. The incidence of gastrointestinal symptoms including diarrhea was significantly higher in the control group than in the study group. There was no significant difference in the incidence of cytomegalovirus infection and other adverse effects.

CONCLUSION

These results suggest the study group therapy is an effective regimen in preventing acute rejection and the deterioration of renal function. These results also show this therapy can reduce the incidence of adverse effects such as gastrointestinal symptoms.

Safety and efficacy of mizoribine treatment in nephrotic syndrome complicated with hepatitis B virus infection: a clinical study

Objective The objective of this study is to explore the efficacy and safety of mizoribine (MZR) in treating nephrotic syndrome patients afflicted with hepatitis B virus (HBV). Methods The present study included 36 nephrotic syndrome patients accompanied with HBV infection. A draft of MZR (150-200 mg/d), methylprednisolone (0.6-0.8 mg/kg·d), and entecavir (0.5 mg/d) was administered to study patients over 24 weeks. The serum albumin (AlB), 24-h urine protein (24-U-TP), liver and renal functions, and HBV-DNA were quantified before and at 2, 4, 8, 12, 16, 20, and 24 weeks after the treatment. The adverse responses were recorded. Results The AlB levels of patients increased gradually after comprehensive treatment, while the 24-U-TP, serum cholesterol, and triglyceride (TG) levels declined gradually. The changes at 24 weeks post-treatment were statistically significant. Compared with the levels before treatment, the HBV-DNA, transaminase, and renal functions of the patients were not significantly altered after the treatment. No evident adverse response was found. Conclusion Treatment using MZR in combination with methylprednisolone and entecavir in HBV-positive nephrotic syndrome patients displays significant efficacy with a low incidence of adverse reactions.

Potential Interaction of Plasmodium falciparum Hsp60 and Calpain

After invasion of red blood cells, malaria matures within the cell by degrading hemoglobin avidly. For enormous protein breakdown in trophozoite stage, many efficient and ordered proteolysis networks have been postulated and exploited. In this study, a potential interaction of a 60-kDa Plasmodium falciparum (Pf)-heat shock protein (Hsp60) and Pf-calpain, a cysteine protease, was explored. Pf-infected RBC was isolated and the endogenous Pf-Hsp60 and Pf-calpain were determined by western blot analysis and similar antigenicity of GroEL and Pf-Hsp60 was determined with anti-Pf-Hsp60. Potential interaction of Pf-calpain and Pf-Hsp60 was determined by immunoprecipitation and immunofluorescence assay. Mizoribine, a well-known inhibitor of Hsp60, attenuated both Pf-calpain enzyme activity as well as P. falciparum growth. The presented data suggest that the Pf-Hsp60 may function on Pf-calpain in a part of networks during malaria growth.

Mizoribine selectively attenuates monocyte chemoattractant protein-1 production in cultured human glomerular mesangial cell: a possible benefit of its use in the treatment of lupus nephritis

AIM

Mizoribine (MZR) is a selective inhibitor of the inosine monophosphate dehydrogenase - a key enzyme in the de novo pathway of guanine nucleotides - that was developed in Japan. Besides its immunosuppressive effects, MZR has recently been reported to suppress the progression of histologic chronicity via suppression of macrophage infiltration of the interstitium in selected patients with lupus nephritis.

METHODS

We examine the direct effect of MZR in human mesangial cells on the expression of functional molecules including monocyte chemoattractants in cultured human mesangial cells (MCs) treated with polyinosinic-polycytidylic acid (poly IC), a synthetic analogue of viral dsRNA, that makes 'pseudoviral' infection, and analyzed the expression of target molecules by reverse transcriptase-polymerase chain reaction and Western blotting. Thereafter, the effect of MZR on the expressions was examined.

RESULTS

Pretreatment of cells with MZR partially, but significantly, attenuates the expression of monocyte chemoattractant protein (MCP)-1 mRNA and protein, whereas the poly IC-induced expressions for the other functional molecules, such as CCL5, fractalkine and IL-8 were not influenced by MZR treatment. On the other hand, pretreatment of cells with tacrolimus did not suppress the expression of MCP-1 mRNA.

CONCLUSION

Mizoribine itself selectively attenuated the expression of MCP-1 both mRNA and protein levels in MCs treated with poly IC; that is, a possible model of 'pseudoviral' infection, which may be involved in the pathogenesis of lupus nephritis.

Long-term post-marketing surveillance of mizoribine for the treatment of lupus nephritis: Safety and efficacy during a 3-year follow-up

OBJECTIVE

To determine the safety and efficacy of long-term use of mizoribine by undertaking a 3-year post-marketing surveillance study.

METHODS

Subjects were all lupus nephritis patients newly treated with mizoribine between 1 October 2003 and 30 September 2005 at contracted study sites.

RESULTS

Mizoribine was administered to 881 lupus nephritis patients in the safety analysis set consisting of 946 patients recruited from 281 contracted study sites after satisfying the eligibility criteria. There were 301 events of adverse drug reactions that were observed in 196 (20.7%) of the 946 subjects. There were 34 events of serious adverse drug reactions in 31 patients (3.2%). No deterioration in hematological and biochemical test values was observed, but immunological testing showed significant improvements in C3, CH50, and anti-DNA antibody titers. The negative rate of proteinuria also increased over time. The median steroid dosage was 15 mg/day at the commencement of treatment, but was reduced to 10 mg/day at 12 months and 8 mg/day at 36 months.

CONCLUSION

The findings of the 3-year long-term drug use surveillance study indicated that mizoribine can be used over the long term with relatively few adverse drug reactions, suggesting its suitability for use in maintenance drug therapy.

Correlation of interleukin-6 and monocyte chemotactic protein-1 concentrations with crescent formation and myeloperoxidase-specific anti-neutrophil cytoplasmic antibody titer in SCG/Kj mice by treatment with anti-interleukin-6 receptor antibody or mizoribine

Myeloperoxidase-specific anti-neutrophil cytoplasmic antibody (MPO-ANCA) is associated with rapidly progressive glomerulonephritis (RPGN) and glomerular crescent formation. Pathogenic factors in RPGN were analyzed by using SCG/Kj mice, which spontaneously develop MPO-ANCA-associated RPGN. The serum concentration of soluble IL-6R was determined by using ELISA and those of another 23 cytokines and chemokines by Bio-Plex analysis. Sections of frozen kidney tissue were examined by fluorescence microscopy and the CD3(+) B220(+) T cell subset in the spleen determined by a flow cytometry. Concentrations of IL-6 and monocyte chemotactic protein-1 were significantly correlated with the percentages of crescent formation. Anti-IL-6R antibody, which has been effective in patients with rheumatoid arthritis, was administered to SCG/Kj mice to elucidate the role of IL-6 in the development of RPGN. MPO-ANCA titers decreased after administration of anti-IL-6R antibody, but not titers of mizoribine, which is effective in Kawasaki disease model mice. These results suggest that IL-6-mediated signaling is involved in the production of MPO-ANCA.

Efficacy of mizoribine-tacrolimus-based induction therapy for pediatric lupus nephritis

BACKGROUND

Recent advances in the management of lupus nephritis (LN) have also contributed to a favorable outcome in patients with pediatric-onset LN. Nevertheless, we believe that a more effective and less toxic treatment is needed to attain optimal control of pediatric-onset LN.

METHODS

Seven consecutive children with biopsy-proven LN (four with class III/IV and three with class V) received multitarget induction therapy consisting of mizoribine (MZR), tacrolimus (Tac), and prednisolone (PDN). They were prospectively evaluated at three, six, and 12 months, and at the latest observation point after a mean period of 32 months. Post-treatment renal biopsy was performed in two patients with class III/IV.

RESULTS

Despite gradually tapering the dose of concomitantly administered PDN, a significant improvement compared with baseline values was observed in the urinary, serological, and clinical assessment measures even at three months of treatment, and the favorable changes persisted throughout the treatment period in most of the study participants except for one. In two patients who underwent post-treatment renal biopsy, a marked histologic improvement was confirmed. No serious adverse events were observed.

CONCLUSIONS

Multitarget therapy may be an attractive option for the treatment of pediatric-onset LN. Further studies involving a larger number of patients are needed.

Mizoribine provides effective treatment of sequential histological change of arteritis and reduction of inflammatory cytokines and chemokines in an animal model of Kawasaki disease

The incidence of panvasculitis in the coronary arteries and aortic root was 100% in the control group. The incidence of panvasculitis in the MZR group decreased to 50%. Moreover, the scope and severity of the inflammation of those sites were significantly reduced in the MZR group as well as the IgG group. On the other hand, increased cytokines and chemokines, such as IL-1α, TNF-α, KC, MIP-1α, GM-CSF, and IL-13, in the nontreatment group were significantly suppressed by treatment with MZR, but the MCP-1 level increased. In addition, IL-1α, TNF-α, IL-10, IL-13, and MIP-1α were suppressed by treatment in the IgG group.

BACKGROUND

Intravenous immunoglobulin (IVIg) treatment results in an effective response from patients with acute-phase Kawasaki disease (KD), but 16.5% of them remain nonresponsive to IVIg. To address this therapeutic challenge, we tried a new therapeutic drug, mizoribine (MZR), in a mouse model of KD, which we have established using injections of Candida albicans water-soluble fractions (CAWS).

METHODS

CAWS (4 mg/mouse) were injected intraperitoneally into C57BL/6N mice for 5 consecutive days. MZR or IgG was administered for 5 days. After 4 weeks, the mice were sacrificed and autopsied, the hearts were fixed in 10% neutral formalin, and plasma was taken to measure cytokines and chemokines using the Bio-Plex system.

RESULTS

The incidence of panvasculitis in the coronary arteries and aortic root was 100% in the control group. The incidence of panvasculitis in the MZR group decreased to 50%. Moreover, the scope and severity of the inflammation of those sites were significantly reduced in the MZR group as well as the IgG group. On the other hand, increased cytokines and chemokines, such as IL-1α TNF-α, KC, MIP-1α, GM-CSF, and IL-13, in the nontreatment group were significantly suppressed by treatment with MZR, but the MCP-1 level increased. In addition, IL-1α, TNF-α, IL-10, IL-13, and MIP-1α were suppressed by treatment in the IgG group.

CONCLUSION

MZR treatment suppressed not only the incidence, range, and degree of vasculitis, but also inflammatory cytokines and chemokines in the plasma of the KD vasculitis model mice, suggesting that MZR may be useful for treatment of KD.

Evaluation of mizoribine as an immunosuppressant in subrenal capsule assay using immunocompetent mice

We studied the application of mizoribine (MZR) to normal immunocompetent mice in subrenal capsule assay (SRCA) by means of tumor growth curve determination, histological analysis and autoradiography. At 400 mg/kg, MZR prolonged the actual tumor growth and moderately reduced the host reaction. Doses below 200 mg/kg did not effectively suppress the host reaction. The maximal weight loss of mice in the 400 mg/kg group reached 29%, but did not exceed 10% within 8 days. Hence, we applied 400 mg/kg of MZR to SRCA for up to eight days for cancer chemotherapy testing. This dose of MZR did not affect the labeling index of tumor cells compared with the control.