Prostaglandin E1 inhibits T-cell proliferation and renal disease in MRL/1 mice

Perioperative prostaglandin e1 infusion in living donor liver transplantation: A double-blind, placebo-controlled randomized trial

The role of prostaglandin E1 (PGE1) infusion in improving early graft function has not been well defined, especially in the scenario of living donor liver transplantation (LDLT). We designed a randomized, double-blind, placebo-controlled trial to evaluate the role of perioperative PGE1 infusion in LDLT. Patients in the study arm received PGE1 (alprostadil) at the rate of 0.25 μg/kg/hour, starting at 1 hour after portal venous reperfusion, and continued for 96 hours. The primary endpoint was early allograft dysfunction (EAD). We analyzed multiple secondary endpoints including postoperative liver function and renal function parameters, acute kidney injury (AKI), hepatic artery thrombosis (HAT), postoperative bleeding, overall mortality, and posttransplant hospital stay. The incidence of EAD was lower in the PGE1 arm, although the difference did not reach statistical significance (22.4% versus 36%; P = 0.21). Among the secondary endpoints, the incidence of AKI was significantly lower in the PGE1 arm (8.2% versus 28%; P = 0.02), as were the peak and mean postoperative creatinine levels. The need for renal replacement therapy was similar between the 2 groups. Among the postoperative graft function parameters, postoperative alanine aminotransferase level was significantly lower in the PGE1 arm (P = 0.04), whereas the remaining parameters including serum bilirubin, aspartate aminotransferase, and international normalized ratio were similar between the 2 arms. There was no difference in the incidence of HAT and postoperative bleeding, in-hospital mortality, and posttransplant hospital stay between the 2 arms. Perioperative PGE1 infusion reduces the incidence of posttransplant renal dysfunction in patients undergoing LDLT. Liver Transplantation 22 1067-1074 2016 AASLD.

IgG3 deficiency extends lifespan and attenuates progression of glomerulonephritis in MRL/lpr mice

Background

Antibodies of the IgG3 subclass have been implicated in the pathogenesis of the spontaneous glomerulonephritis observed in mice of the MRL/MpJ-Tnfrsf6lpr (MRL/lpr) inbred strain which have been widely studied as a model of systemic lupus erythematosus We have produced IgG3-deficient (-/-) mice with the MRL/lpr genetic background to determine whether IgG3 antibodies are necessary for or at least contributory to MRL/lpr-associated nephritis.

Results

The gamma3 genotype (+/+ vs. +/- vs. -/-) did not appear to significantly affect serum titers of IgG auto-antibodies specific for double-stranded DNA (dsDNA) or α-actinin. However, while substantial serum titers of IgG3 auto-antibodies specific for double-stranded DNA (dsDNA) or α-actinin were seen in gamma3 +/+ mice, somewhat lower serum titers of these IgG3 auto-antibodies were found in gamma3 +/- mice, and gamma3 -/- mice exhibited baseline concentrations of these auto-antibodies. Analysis of immunoglobulins eluted from snap-frozen kidneys obtained from mice of all three gamma3 genotypes at ~18 weeks of age revealed much higher quantities of IgG in the kidneys from gamma3 +/+ than gamma3 -/- mice, and most IgG eluted from +/+ mice was IgG3. The serum creatinine levels in gamma3 +/+ mice substantially exceeded those of age-matched gamma3 -/- mice after ~21 weeks of age. Histopathological examination of kidneys from mice sacrificed at pre-determined ages also revealed more extensive glomerulosclerosis in gamma3 +/+ or +/- mice than in -/- mice beginning at 21 weeks of age. Survival analysis for IgG3-deficient and IgG3-producing MRL/lpr mice revealed that gamma3 -/- mice lived significantly longer (p = 0.0006) than either gamma3 +/- or +/+ mice. Spontaneous death appeared to be due to irreversible renal failure, because > 85% of glomeruli in kidneys from mice that died spontaneously were obliterated by glomerulosclerosis.

Conclusions

The available evidence suggests that IgG3 deficiency partially protects MRL/lpr mice against glomerulonephritis-associated morbidity and mortality by slowing or arresting the progression to glomerulosclerosis.

Reviewers

This article was reviewed by Pushpa Pandiyan, Irun Cohen, and Etienne Joly.

The beneficial effects of treatment with all-trans-retinoic acid plus corticosteroid on autoimmune nephritis in NZB/WF mice

Corticosteroids are highly effective anti-inflammatory or immunosuppressive drugs used commonly to treat human systemic lupus erythematosus (SLE). All-trans-retinoic acid (ATRA), which belongs to a class of retinoids that exert immunomodulatory and anti-inflammatory functions, can also suppress the development of lupus nephritis in an animal model. However, both agents can inflict serious adverse effects. Here, we have asked whether ATRA can serve as a steroid-sparing drug in the treatment of lupus nephritis. To examine the efficacy of combining predonisolone (PSL) with ATRA, we treated intraperitoneally New Zealand black/white F1 (NZB/W F1) mice with PSL, ATRA or both agents. Survival rate and proteinuria were determined once a month. Cytokine and anti-DNA antibody production were determined by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). Renal histopathology was observed by haematoxylin and periodic acid Schiff (PAS), immunoperoxidase and immunohistochemical assay. Survival rate and proteinuria were improved in all experimental groups, and were much improved in the mice receiving the combination of ATRA and PSL (P <0.05). A single administration of ATRA reduced the Th1 [interleukin (IL)-2, interferon (IFN)-gamma and IL-12], and a Th2 (IL-4) cytokine level, as effectively as administration of PSL. ATRA also suppressed the expression of inducible nitric oxide synthetase (iNOS) and monocyte chemoattractant protein-1 (MCP-1) in the kidney. The combination of PSL and ATRA significantly reduced IgG2 (especially IgG2b)-specific anti-DNA antibody levels in comparison with administration of either agent alone. These data suggest that ATRA might have the potential to act as a new therapeutic and steroid-sparing drug against lupus nephritis.

Costimulation by B7-1 and B7-2 is required for autoimmune disease in MRL-Faslpr mice

Autoimmune lupus nephritis is dependent on infiltrating autoreactive leukocytes and Igs. B7 costimulatory molecules (B7-1 and B7-2) provide signals essential for T cell activation and Ig class switching. In MRL-Faslpr mice, a model of human lupus, although multiple tissues are targeted for autoimmune injury, nephritis is fatal. We identified intrarenal B7-1 and B7-2 expression, restricted to kidney-infiltrating leukocytes, before and increasing with progressive nephritis in MRL-Faslpr mice. Thus, we hypothesized that the B7 pathway is required for autoimmune disease in MRL-Faslpr mice. To investigate the role of B7 costimulatory molecules in this autoimmune disease, we generated a MRL-Faslpr strain deficient in B7-1 and B7-2. Strikingly, MRL-Faslpr mice lacking both B7 costimulators do not develop kidney (glomerular, tubular, interstitial, vascular) pathology, or proteinuria, and survive far longer. Intrarenal downstream effector transcripts (IFN-gamma, IL-12, monocyte chemoattractant protein-1, CSF-1) linked to nephritis remained at normal levels compared with wild-type mice. Skin lesions and lymphoid enlargement characteristic of MRL-Faslpr mice were diminished in B7-1/B7-2-deficient MRL-Faslpr mice. B7-1/B7-2-deficient MRL-Faslpr mice did not develop leukocytic infiltrates, elevated serum IgG and isotypes (G1,G2b,G3), autoantibodies, and intrarenal IgG deposits. Our findings demonstrate that B7-1 and B7-2 costimulatory pathways are critical to the pathogenesis of autoimmune lupus.

Inhibition of mesangial cell nitric oxide in MRL/lpr mice by prostaglandin J2 and proliferator activation receptor-gamma agonists

MRL/Mp-lpr/lpr (MRL/lpr) mice develop immune complex glomerulonephritis similar to human lupus. Glomerular mesangial cells are key modulators of the inflammatory response in lupus nephritis. When activated, these cells secrete inflammatory mediators including NO and products of cyclooxygenase perpetuating the local inflammatory response. PGJ2, a product of cyclooxygenase, is a potent in vitro inhibitor of macrophage inflammatory functions and is postulated to function as an in vivo inhibitor of macrophage-mediated inflammatory responses. We hypothesized that in lupus, a defect in PGJ2 production allows the inflammatory response to continue unchecked. To test this hypothesis, mesangial cells were isolated from MRL/lpr and BALB/c mice and stimulated with IL-1beta or LPS plus IFN-gamma. In contrast to the 2- to 3-fold increase in PGJ2 production by stimulated BALB/c mesangial cells, supernatant PGJ2 did not increase in MRL/lpr mesangial cell cultures. NO production in stimulated MRL/lpr and BALB/c mesangial cells, was blocked by PGJ2 and pioglitazone. These studies suggest that abnormalities in PGJ2 production are present in MRL/lpr mice and may be linked to the heightened activation state of mesangial cells in these mice.

Up-regulation of tubular epithelial interleukin-12 in autoimmune MRL-Fas(lpr) mice with renal injury

Phagocyte-derived interleukin-12 (IL-12) is a key cytokine that induces the development of an effective Th1 type immune response in various inflammatory and infectious disorders. To determine the importance of IL-12 in the pathogenesis of autoimmune renal injury we examined the renal production of this heterodimeric cytokine in the MRL-Fas(lpr) lupus nephritis model. Compared with normal mice RT-PCR products encoding both the p35 and p40 subunits of IL-12 were markedly increased in the kidney of MRL-Fas(lpr). Immunofluorescence staining demonstrated expression of the IL-12 p75 heterodimer on isolated infiltrating mononuclear cells and also on proximal tubular epithelial cells in MRL-Fas(lpr) but less in normal mice kidneys. The enhanced expression of IL-12 correlated with an increased intrarenal transcription of IFN-gamma. The p35 and p40 transcripts and soluble IL-12 p75 protein were also produced by cultured TEC. In addition, membrane bound IL-12 was detected on Tec. We conclude that IL-12 production is significantly up-regulated in MRL-Fas(lpr) lupus nephritis. In addition to mononuclear cells, TEC are an important source of IL-12 and could thereby participate in the development of a Th1 type immune response in autoimmune renal injury.

Combined treatment of autoimmune MRL/MP-lpr/lpr mice with a herbal medicine, Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to) plus suboptimal dosage of prednisolone

Therapeutic effects of combined treatment with a Chinese medicine prescription, Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to, NYT) and suboptimal doses of prednisolone (PSL) on pathological findings of autoimmune-prone MRL/lpr mice were examined. Six-week-old MRL/lpr mice were treated orally with 1000 mg/kg of NYT, 0.5 or 2 mg/kg of PSL, 1000 mg/kg of NYT plus 0.5 or 2 mg/kg of PSL (combined treatment) or solvent only (control) six times per week. The rates of signs and symptoms of autoimmune disease (lymphadenopathy, proteinuria, dermatitis, loss of hair) were suppressed significantly in groups given PSL (2 mg/kg) alone, NYT alone and combined treatment with PSL (2 mg/kg) plus NYT (1000 mg/kg) compared with control, respectively, whereas treatment with PSL (0.5 mg/kg) alone did not inhibit their occurrence. ConA response and IL-2 production were also improved significantly in lymphocytes of mice given the combined treatment. Interestingly, treatment with NYT alone enhanced further the augmented IFN-gamma production in MRL/lpr mice but the combined treatment suppressed such an augmented production. The combined treatment dramatically reduced the level of anti-DNA antibodies in serum of MRL/lpr mice. By contrast, NYT alone treatment had no effect on autoantibodies production. These results suggest that combined treatment with NYT plus a suboptimal dose of PSL could be effective for systemic lupus erythematosus without severe side-effects.

Inhibition of IFN-gamma induction of class II MHC genes by cAMP and prostaglandins

Triggering of the cyclic AMP (cAMP) signal transduction pathway inhibits the the interferon gamma (IFN-gamma)-mediated induction of class II major histocompatibility (MHC) genes. We have investigated the mechanism of the inhibition of IFN-gamma induction of the murine A alpha class II MHC gene by cAMP and E series prostaglandins (PGEs). 151 base pairs of the A alpha promoter were sufficient to confer positive regulation by IFN-gamma and negative regulation by cAMP which accurately mirrored the regulation of the endogenous A alpha gene. cAMP also inhibited the IFN-gamma activation of the Fc gamma receptor I (Fc gamma RI) gene promoter, an "early" promoter which is activated immediately after treatment of cells with IFN-gamma. PGEs, which cause an elevation in intracellular cAMP, inhibited the induction of the A alpha promoter, and inhibition was greater in the presence of tumor necrosis factor alpha (TNF alpha). A mutational analysis of the A alpha promoter showed that all four conserved class II promoter elements, the S, X1, X2, and Y boxes, play a role in mediating A alpha promoter activation by IFN-gamma. Mutations in these elements did not diminish the cAMP inhibition of promoter activation by IFN-gamma. Thus, conserved class II promoter sequences which mediate most known examples of positive and negative regulation, including cAMP inhibition of constitutive class II expression, do not mediate cAMP inhibition of IFN-gamma activation of the A alpha promoter. We suggest that this inhibition may be mediated by a novel class II promoter element or by disruption of an early step in the IFN-gamma signal transduction pathway.

Treatment effect of a traditional Chinese medicine, ren-shen-yang-rong-tang (Japanese name: ninjin-youei-to), on autoimmune MRL/MP-lpr/lpr mice

MRL/Mp-lpr/lpr (MRL/lpr) mice were treated with a traditional Chinese herbal medicine, Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to, NYT) intraperitoneally (i.p.) every 3 days or per os (p.o.) 6 times/week from before the onset of autoimmune disease (6 weeks of age). Fifty percent survival time was found in placebo-controlled male and female mice of 28 and 22 weeks of age, respectively. NYT-treatment markedly prolonged the survival time of MRL/lpr mice. That is, 50% survival time was 43 weeks in the i.p.-treated male mice and 30 weeks of age in the p.o.-treated female mice. Further, NYT-treatment significantly reduced occurrence of thymic atrophy and prevented the anomalous accumulation of B220+ T-cells in lymph node and spleen, both of which are characteristic in MRL/lpr mice. Moreover, grades of proteinuria were significantly reduced in both the i.p.- and p.o.-treated groups compared with the control groups. Such clinical benefit and increased survival time were interestingly not associated with the decrease in the level of autoantibodies.

Pancreas-specific venular labeling by monastral blue B in the BB rat: modulation by prostaglandins and their inhibitors

Leaky blood vessels in the microcirculation can be detected in vivo by injecting an animal with colloidal pigments like Monastral blue B (MbB). We have previously used this labeling method in the BB rat, an animal model of spontaneous autoimmune diabetes, and detected increased vascular permeability restricted to the venules of the pancreas. The earlier data suggested that pancreata of animals susceptible to labeling contain trapped intravascular monocytes that are activated to release vasoactive mediators after phagocytosis of MbB. To explore these observations further, we investigated the effects of prostaglandins on this system. Prostaglandins are known to be important mediators of inflammatory responses and to modulate the expression of disease in other animal models of autoimmunity. We now report that MbB-induced pancreatic labeling is modulated by misoprostol (an analogue of prostaglandin E1), prostaglandins of the E series, and inhibitors of prostaglandin synthesis. The nonsteroidal anti-inflammatory drugs ibuprofen and ketorolac both reduced the intensity of labeling in susceptible BB rats in a dose dependent manner. In contrast, both misoprostol and prostaglandin E2 given at low doses induced pancreatic permeability in the labeling-resistant Wistar Furth rat. To extend this finding, we also tested much higher drug doses, since at high concentrations, E series prostanoids exert anti-inflammatory effects. We observed that large doses of prostaglandin E1, prostaglandin E2, and misoprostol all suppressed labeling in the BB rat. We conclude that presence of MbB in the pancreatic circulation of the rat induces organ specific venular leakage by an inflammatory process involving prostaglandins.

NZB/NZW F1 mouse nephritis and immune response are not changed by treatment with a 15-lipoxygenase derivative

15-HETE is an arachidonic acid derivative issued from the 15 lipoxygenase pathway. This fatty acid possesses immunomodulatory capabilities since it was reported that it generates CD8 + suppressor T-cells either in vitro or ex vivo. The aim of the present report was to study if the suppressive capabilities of 15-HETE were able to influence the onset of the NZB/NZW Fl auto-immune disease. For that purpose we produced 15-HETE and injected the eicosanoid twice a week to NZB/WFI mice for 40 weeks. During the 15-HETE treatment of the animals it was observed an augmentation of the proliferative response of lectin-stimulated splenocytes (at weeks 20 and 30) then the thymidine uptake decreased (at week 40). In fact we observed that among 15-HETE treated mice the evolution of the nephropathy was not changed, the 'glomerular activity score' remained the same for the treated animals compared to controls. On the contrary antinuclear antibodies occurred earlier even if in some experiments the generation of CD8 + cells was demonstrated.

Altering the course of proliferative nephritides: the challenge of the 1990s

There is considerable evidence based on experimental pathology that heparin/heparinoids will benefit the course of the various forms of human proliferative nephritis. An alternative to heparin may be pentosan polysulphate. Another possibility is the infusion of prostaglandin E1 because of its anti-inflammatory and potentially antiproliferative actions. Both these approaches mimic natural pathophysiological control mechanisms.

Enhanced tumor necrosis factor in anti-CD3 antibody stimulated diabetic NOD mice: modulation by PGE1 and dietary lipid

Administration of OKT3 anti-CD3 monoclonal antibody (mAb) to patients for transplant rejection, is associated with a distinct and often severe clinical syndrome related to massive cytokine release. Previous reports have similarly demonstrated increased levels of serum tumor necrosis factor alpha (TNF alpha) in normal mice following administration of 1452-C11 anti-CD3 mAb. In this study, we compared serum TNF alpha levels at baseline and after anti-CD3 stimulation among three groups of mice: normal BALB/c controls, pre-diabetic non-obese diabetic (NOD) mice, and diabetic NOD mice. Baseline serum TNF alpha levels, as measured by L929 cell bioassay, were 2xhigher in diabetic NOD and 3xhigher in pre-diabetic NOD compared with BALB/c. Ninety minutes after anti-CD3 mAb stimulation, serum from BALB/c controls and pre-diabetic NOD contained 2- to 8-fold higher levels of TNF-alpha as compared to untreated control mice. In contrast, following anti-CD3 mAb, there was a dramatic 20-fold increase in serum TNF alpha in diabetic NOD mice (levels > 5000 pg/ml). Additionally, anti-CD3 mAb increased the steady-state TNF alpha mRNA transcripts. Spleens from diabetic mice given anti-CD3 mAb had higher steady-state TNF alpha mRNA than spleen from normal mice similarly treated. The enhanced release of circulating TNF alpha after anti-CD3 mAb in diabetic NOD mice was abrogated by pre-treatment of mice with prostaglandin E1 (PGE1) 30 min prior to anti-CD3 mAb stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Repression of class II major histocompatibility complex genes by cyclic AMP is mediated by conserved promoter elements

The induction of cell surface expression of class II major histocompatibility complex (MHC) antigens by interleukin (IL)-4 and interferon (IFN)-gamma is inhibited by elevation of intracellular cyclic (c)AMP, which is caused by immunomodulatory agents such as E series prostaglandins (PGEs). To investigate the mechanism of this downregulation, we have analyzed the consequences of elevating intracellular cAMP on cell surface expression, mRNA levels, and promoter activity of the murine A alpha and E beta class II MHC genes. Elevation of cAMP resulted in a coordinate repression of both basal and inducible A alpha and E beta expression. 151 and 192 base pairs of A alpha and E beta promoter sequence, respectively, were sufficient for conferring repression by cAMP on a reporter gene. A mutational analysis of the A alpha promoter revealed that cAMP downregulation is mediated by the conserved S and X1 DNA elements, which are also necessary for induction by cytokines. Downregulation by cAMP was not dependent on an intact X2 site, which is identical in sequence to the CRE element which mediates the positive regulation of several genes by cAMP. These results identify the DNA elements which mediate repression of class II MHC genes by cAMP and show that the same DNA sequences can mediate both positive and negative regulation of class II MHC expression.

Prostanoids in paediatric kidney diseases

Prostanoids belong to the growing family of eicosanoids, which are all derived from arachidonic acid. Prostanoids act as modulators and mediators in a large spectrum of physiological and pathophysiological processes within the kidney. On the one hand, the potent vasoconstrictor and platelet-aggregating thromboxane (TX) A2 is involved in the pathophysiology of a variety of glomerular diseases, such as haemolytic-uraemic syndrome and immune-mediated glomerulopathies. Prostaglandin (PG) E2, on the other hand, interferes with tubular electrolyte and water handling. Clinical data support the hypothesis that this member of the prostanoid family contributes to the pathophysiology of Bartter's syndrome, hyperprostaglandin E syndrome, idiopathic hypercalciuria and renal diabetes insipidus. Both prostanoids, TXA2 and PGE2, are involved in the pathophysiology of obstructive uropathies. The physiological and protective role of renal vasodilator prostanoids (PGI2 and PGE2) has been studied during treatment with non-steroidal anti-inflammatory drugs. Part of the pharmacological effects of frusemide and converting enzyme inhibitors is mediated by PGI2 and PGE2. The role of renal prostanoids in cyclosporine toxicity is still equivocal. Future investigations on the physiological and pathophysiological role of renal prostanoids will have to consider the multiple interactions between prostanoids on the one hand, and classical hormones and other mediators (e.g. cytokines) on the other hand.

Increased expression of Ia antigens on B cells after neonatal induction of lymphoid chimerism in mice: role of interleukin 4

BALB/c mice rendered chimeric at birth by injection of 10(8) (A/J X BALB/c)F1 spleen cells develop a lupus-like autoimmune disease linked to the activation of donor B cells by host T cells. As in vitro studies previously indicated that interleukin 4 (IL4) was a mediator of the interactions between T and B cells, we analyzed the intensity of Ia antigen expression on B cells of chimeric mice. Flow cytometric analysis with anti-Ia monoclonal antibodies (mAb) revealed that B cells from spleens and lymph nodes of 2-week-old chimeric BALB/c mice displayed a two- to threefold increase in membrane Ia antigen expression, this increase still being present in spleens of 30-week-old animals. An increase in Ia antigen expression was also found in the small number of donor B cells detected in spleens and lymph nodes of chimeric mice. IL4 was the major stimulus leading to increased B cell Ia antigen expression, as this phenomenon was substantially prevented by in vivo treatment of chimeric mice with the anti-IL4 11B11 mAb. In vitro experiments revealed that host splenic T cells of chimeric mice, while unable to generate anti-donor cytotoxic T lymphocytes, secreted significant amounts of IL 4 when stimulated in mixed lymphocyte cultures (MLC) with donor alloantigens. This IL4 secretion led to an increased expression of Ia antigens on donor-type F1 B cells present in MLC. No significant increase in Ia antigen expression was found on syngeneic BALB/c B cells co-cultured with T cells from chimeric mice unless A/J B cells were added to the cultures. Taken together, these findings indicate that increased Ia antigen expression on donor B cells is induced by IL4 secreted by anti-donor T cells. IL4 released in this setting also leads to increased Ia antigen expression on host B cells through a bystander effect.

Prostaglandin E1 suppresses macrophage infiltration and ameliorates injury in an experimental model of macrophage-dependent glomerulonephritis

Prostaglandin E1 (PGE1) suppresses macrophage infiltration and ameliorates injury in an experimental model of macrophage dependent glomerulonephritis. Macrophages are mediators of glomerular injury in models of proliferative glomerulonephritis. We have recently shown that macrophages in glomerulonephritis have low prostaglandin E2 (PGE) generation, and other evidence implicates eicosanoids as regulators of macrophage activation. Here we have studied in rats the effect of 15(s)-15-methyl PGE1 (M-PGE1) on accelerated nephrotoxic nephritis, a model of acute macrophage-dependent glomerular injury. M-PGE1 ameliorated proteinuria (day 4; 61 +/- 13 mg/24 h, n = 9; vehicle treated, 164 +/- 17 mg/24 h, n = 11; P less than 0.002) and glomerular hypercellularity; quantification of infiltrating macrophages by isolating glomerular cells showed reduction in the numbers of macrophages (44 +/- 9/glomerulus; vehicle treated, 119 +/- 15/glomerulus; P less than 0.02) with inhibition of Ia antigen expression on infiltrating macrophages (8 +/- 5%; vehicle treated 25 +/- 4% P less than 0.05). Glomerular binding of nephrotoxic globulin and levels of autologous antibodies were not affected by M-PGE1. Thus the mechanism of suppression involves inhibition of macrophage accumulation and activation. M-PGE1 administered to normal rats did not affect numbers of resident leucocytes (12.6 +/- 1.5/glomerulus; vehicle treated, 13.2 +/- 1.3/glomerulus) or alter Ia antigen expression (4.1 +/- 0.2 Ia + cells/glomerulus; vehicle treated, 3.9 +/- 0.6/glomerulus). This study suggests a therapeutic role for PGE1 in this type of glomerulonephritis, and has implications for the pathophysiology of macrophage-mediated inflammation.

The treatment of lupus nephritis

The literature on the treatment of lupus nephritis is scattered, much of it in rheumatological rather than nephrological journals. Whatever our ignorance of the nature and genesis of lupus nephritis, under empirical treatment the prognosis, especially for severe forms, has improved dramatically during the past 20 years. For severe lupus nephritis, the evidence that the addition of cytotoxic agents to corticosteroids improves outcome is now secure, and discussion centres mainly on which drug to use and by what route. Intravenous methylprednisolone is at least as effective as high-dose tapering oral therapy for initial treatment, and carries fewer side-effects. The role of plasma exchange in lupus remains undefined: it may have a role in the treatment of cerebral manifestations or otherwise resistant patients, but controlled trials have failed to show benefit. Future developments will probably centre around the use of specific monoclonal antibodies which target specific groups and subgroups of cells, "humanised" by the splicing of human Fc piece to rodent (fab)2, perhaps bearing toxins. To use these agents to best advantage, however, we will have to understand better than we do today the nature of the cellular defects in the immune response which underlie the lupus syndrome.

Combined treatment of autoimmune MRL/Mp-lpr/lpr mice with cholera toxin plus irradiation. Combined treatment of autoimmune MRL/l mice

MRL/Mp-lpr/lpr (MRL/1) mice spontaneously develop autoimmune diseases like systemic lupus erythematosus (SLE) from 2 months of age, accompanied by massive lymphadenopathy. Such mice of 2 months of age were treated with 1 microgram cholera toxin (CT) every 7 days and/or with 400 rad of one-shot 60Co irradiation. CT treatment alone markedly improved nephritis as evaluated by proteinuria and moderately suppressed lymphadenopathy and anti-DNA antibody production, while irradiation alone prominently improved lymphadenopathy but showed little effect on both nephritis and anti-DNA antibody production. On the other hand, when mice were treated with the combination of CT plus irradiation, autoimmune nephritis as well as anti-DNA production and lymphadenopathy were almost completely inhibited. Taken together, each agent exerts the improvement effect at the different points from each other in an abnormal immunological circuit displayed in MRL/1 mice. This kind of combined treatment may be applicable to the clinical use for autoimmune diseases.

Effects of a specific thromboxane synthetase inhibitor on development of experimental Dirofilaria immitis immune complex glomerulonephritis in the dog

Twelve Beagle dogs were immunized with aqueous-soluble Dirofilaria immitis antigens, and subsequent to at least fivefold increases in serum antibody titer, 6 mg of homologous antigen was infused into the left renal artery. Six dogs were treated once daily starting the day of infusion with 0.75 mg/kg of 1-benzylimidazole (1-BIM) in saline. Six control dogs were given saline only. Light, immunofluorescent, and transmission electron microscopic examinations of renal tissue from control dogs, 10 days after antigen infusion, showed a mesangioproliferative glomerulonephritis in the left kidney with polymorphonuclear leukocyte (PMNL) infiltration and fibrin deposition. Immunoglobulin (Ig) G, M, C3, and Dirofilaria antigen deposits were observed in a segmental granular pattern. Mesangial, subendothelial, and intramembranous electron dense deposits were observed, and anti-Dirofilaria antibodies were demonstrated in kidney eluates from each dog. Administration of 1-BIM had no significant effect on IgG, IgM, C3, or antigen deposits, electron dense deposits, or concentration of antibody in kidney eluates. However, 1-BIM-treated dogs had less glomerular cell proliferation, periodic acid-Schiff (PAS) positive glomerular staining, PMNL infiltration, and fibrin deposition. These data suggest that thromboxane is an important mediator in the development of immune complex glomerulonephritis, and that in certain circumstances, inhibition of thromboxane synthesis may be an effective therapy for immune complex glomerulonephritis in the dog.

Aberrant production of leukotriene C4 by macrophages from autoimmune-prone mice

Eicosanoids have been implicated in the pathogenesis of autoimmune diseases. In this study, peritoneal macrophages from autoimmune-prone mice were examined for their capacity to produce proinflammatory 5-lipoxygenase metabolites. The results indicate that enhanced production of leukotriene C4 is a common feature of murine autoimmunity and suggest further that aberrations in 5-lipoxygenase activity may play a role in the development of lupus.

The effects of E series prostaglandins on blastogenic responses in vitro and graft vs. host responses in vivo

In this study the ability of prostaglandin E1 (PGE1), Misoprostol (a stable analog of PGE1), and 16,16-dimethyl PGE2 (a stable analog of PGE2) to suppress immune responses in vitro and in vivo was determined. All of the compounds caused a titratable (10(-6) to 10(-9) M) suppression of Con A blastogenesis and the mixed lymphocyte response whereas there was only slight inhibition of the LPS response. When either 16,16-dimethyl PGE2 (30 ug/mouse) or Misoprostol (60 ug/mouse) was administered daily in vivo, there was a significant suppression of splenomegaly in F1 mice (C57Bl/6 x CBA) which had been injected with parental (C57Bl/6) spleen cells. We conclude that prostaglandins of the E series can function as immunosuppressive reagents both in vitro and in vivo. In the future they may serve to augment existing forms of immunosuppressive therapy.

An immunomodulating anti-rheumatic drug, lobenzarit disodium (CCA): inhibition of polyclonal B-cell activation and prevention of autoimmune disease in MRL/Mp-lpr/lpr mice

In this study, we examined the effect of an immunoregulatory antirheumatic agent, lobenzarit disodium (CCA), on spontaneously developing glomerulonephritis in MRL/Mp-lpr/lpr (MRL/l) mice. Starting from 6 weeks of age, mice were given CCA orally 5 days a week at a dose of 2 or 10 mg/kg. A control group was given the same volume of distilled water. The CCA treatment suppressed the excretion of protein in the urine. At 40 weeks of age, the incidence of proteinuria was 10/10 in the controls, 6/10 in the 2-mg/kg treatment group, and 5/10 in the 10 mg/kg group. The life span was prolonged dose dependently. The 50% survival time was 33 weeks for the controls, 35.5 weeks for the 2-mg/kg group, and 41 weeks for the 10-mg/kg group. The serum levels of anti-ssDNA antibody, anti-TNP antibody, and rheumatoid factor (RF) of the Ig G isotype and immune complex were reduced compared with control group. But the antibodies of Ig M isotype were not reduced. The serum Ig G1, Ig G2, and Ig G3 were significantly lower in the CCA-treated mice than in the controls. But again the serum level of Ig M was unchanged. These effects of CCA may be based on the suppression of lymphadenopathy. CCA may correct abnormal B-cell growth and differentiation factor release by the MRL/l abnormal T cells. These results show that CCA inhibits the development of lupus nephritis in MRL/l mice through the amelioration of the abnormal immune response, polyclonal B-cell activation.

Mechanism of prostaglandin E2 inhibition of acute changes in vascular permeability

In order to determine the mechanism of antiinflammatory activity, prostaglandin E2 (PGE2) or diluent was administered to rats 2 h prior to intradermal injections of various mediators of inflammatory vascular permeability changes. Vascular permeability was measured as the accumulation of [125I]rat serum albumin at the site of mediator injunction. PGE2 at 500 micrograms significantly inhibited protein leakage produced by histamine, platelet activating factor, zymosan, and zymosan-activated plasma. Pretreatment with PGE2 had no effect on protein leakage induced by injection of lysosomal enzymes, glucose oxidase, or xanthine oxidase. The accumulation of polymorphonuclear leukocytes (PMNs) at the site of injection of zymosan or zymosan-activated plasma was not altered by PGE2 administration. In separate experiments, the ability of PGE2 to alter phagocytosis and oxygen radical production by PMN was examined. PGE2 significantly inhibited phagocytosis at 2 h, but this returned to normal by 6 h. Production of hydrogen peroxide by PMN was not affected by PGE2. These results suggest that PGE2 prevents acute changes in vascular protein leakage by preventing endothelial cell contraction and by inhibiting specific PMN functions.

Prostaglandin E1 inhibits effector T cell induction and tissue damage in experimental murine interstitial nephritis

Immunosuppressive effects of E-series prostaglandins have been demonstrated in many in vitro assays of immune responsiveness as well as in autoimmune diseases. To explore the mechanisms underlying prostaglandin E1 (PGE1)-associated immunosuppression in autoimmunity, we treated SJL mice immunized to produce immune-mediated interstitial nephritis with PGE1, PGF2 alpha, or vehicle alone. Mice receiving PGE1 treatment do not develop interstitial nephritis, nor do they display delayed-type hypersensitivity (DTH) to the immunizing renal tubular antigen preparation. The observed immunosuppression is critically dependent on PGE1 administration during the period of effector T cell induction. We therefore investigated the effect of PGE1 on the in vitro induction of DTH effector T cells reactive to renal tubular antigens (SRTA). PGE1 inhibits effector T cell induction in a dose-dependent, reversible manner, but has no inhibitory effect on fully differentiated DTH effector cells or SRTA-reactive cell lines. The PGE1 effect is indirect and mediated via nonspecific suppressor lymphokines. This suppression can be overcome by recombinant interleukin 1 (IL-1), which suggests a mechanism related to either diminished IL-1 secretion or target cell sensitivity to IL-1.

Spleen cell factor inhibits lymphoproliferation, abnormal Ia expression and overt autoimmunity in MRL-lpr mice

Autoimmune MRL-lpr have an abnormal pattern of lymphokine production. In our attempt to repair this defect, MRL-lpr mice were prophylactically treated daily with a lectin stimulated rat spleen cell product rich in interleukin-2. Therapy inhibited the lymphoid hyperplasia of the unique lymphocytes regulated by the lpr gene, suppressed the enhanced supranormal expression of Ia on peritoneal macrophages and protected this strain from autoimmune renal injury. Purified recombinant interleukin-2 alone did not prevent autoimmune disease expression. Thus, a spleen cell product other than interleukin-2 can ameliorate the aggressive course of lymphoproliferation and autoimmunity in MRL-lpr mice.

[The significance of eicosanoids in glomerular diseases]

Prostanoids are local cyclooxygenase products, synthesized by mesangial and epithelial cells of the glomerulus as well as by a variety of inflammatory cells and platelets. Prostaglandins and thromboxane have direct vasodilatory and vasoconstrictory effects and can modulate glomerular function. Arachidonic acid, the main substrate for cyclooxygenase, can also be metabolized by the lipoxygenase pathway to leukotrienes, substances which are primarily synthesized in inflammatory cells. In several models induction of immunologic glomerular injury is associated with an increased glomerular formation of cyclooxygenase and lipoxygenase products. The changes in cyclooxygenase products have been shown to account for some hemodynamic changes found in some of these models. Increased renal prostanoid formation is also present in patients with glomerular disease. There is some evidence that increased renal PG-formation in patients with moderate glomerular disease regulates GFR and mediates proteinurie in some of these patients. Leukotrienes are chemotactive substances which modulate the function of inflammatory cells, stimulate the growth of mesangial cells, and constrict mesangial cells in culture. Thus, these compounds might be mediators in the induction of immune mediated glomerular disease.

Effect of prostaglandin E1 in brown Norway rats with mercury-induced autoimmune disease

The effect of prostaglandin E1 on mercury-induced autoimmune disease in brown Norway rats has been investigated. Daily doses of 6 to 24 micrograms prolonged survival and significantly decreased proteinuria, deposition of immune reactants in the glomeruli, circulating anti-glomerular membrane antibody production, total serum IgE, and circulating immune complex level. A dose of 3 micrograms was also effective but to a lesser degree. These results show the efficiency of prostaglandin E1 in yet another autoimmune disease, show that the beneficial effect of prostaglandin E1 in this model is related to its immunosuppressive effects, and suggest that modification of prostaglandin-mediated suppression induced by HgCl2 might play a role in the pathogenesis of this autoimmune disease.

Eicosanoids in experimental and human renal disease

The renal prostaglandins and thromboxanes are powerful autacoids with potential effects on renal hemodynamics, salt and water metabolism, and the immune system. The possibility of adverse effects on renal function in certain patients with renal disease due to cyclooxygenase inhibition with nonsteroidal anti-inflammatory drugs has long been appreciated. Experimental evidence indicates that renal prostaglandin and thromboxane production is increased in several models of renal disease and that similar decrements in renal function occur with cyclooxygenase inhibition and may be due to inhibition of vasodilator prostaglandins. Additionally, several investigators have shown that administration of prostaglandins may be therapeutic in some forms of renal disease, particularly immunologically mediated diseases. Dietary modification to affect prostaglandin production has also been promising in certain experimental models. In contrast to vasodilator prostaglandins, thromboxane is a potent vasoconstrictor and would be expected to have adverse effects on renal function. Despite demonstration of elevated glomerular thromboxane, studies using inhibitors of thromboxane synthesis in immunologically mediated glomerular disease have been disappointing. There is some evidence, however, that these drugs may be of benefit in ureteric obstruction and renal transplant rejection.

Increased renal thromboxane production in murine lupus nephritis

To determine whether the amount of cyclooxygenase metabolites correlates with the development of lupus nephritis, intrarenal eicosanoid production was measured in autoimmune mice. Disease progression was related to the renal biosynthesis of prostaglandin (PGE2), prostacyclin (6 keto PGF1 alpha), and thromboxane (TXB2) using the MRL-lpr and NZB X NZW F1 hybrid mouse strains with predictably progressive forms of renal disease that mimic the human illness. Mice were evaluated for renal disease by measuring urinary protein excretion and renal immunopathological conditions and these features were related to renal eicosanoid production. These studies show that: (a) intrarenal synthesis of TXB2 increased incrementally in MRL-lpr and NZB X NZW F1 hybrid mice as renal function deteriorated and renal pathologic events progressed; (b) there were no consistent increases in the levels of two other cyclooxygenase metabolites, PGE2 or 6 keto PGF1 alpha; (c) increased TXB2 production occurred in the renal medulla, cortex, and within enriched preparations of cortical glomeruli; (d) when renal disease was prevented by pharmacologic doses of PGE2, intrarenal TXB2 did not increase; (e) administration of a dose of ibuprofen (9 mg/kg), a cyclooxygenase inhibitor capable of reducing 90% of platelet TXB2 without affecting intrarenal levels, did not retard the progression of renal damage. Taken together, these data indicate that the intrarenal level of TXB2 rises in relation to the severity of murine lupus nephritis. Furthermore, because of the potential deleterious effects of TXA2, enhanced production of this eicosanoid may be an important mediator of renal injury.

A functional analysis of the T-cell defect in MRL-lpr mice

Autoimmune MRL-lpr mice have a defect in antigen-specific T-cell proliferation. Our studies indicate that this defect is caused by the massive expansion in MRL-lpr mice of a unique T-cell subset which is unresponsive to antigenic signals. Pharmacologic doses of PGE1 suppress this lymphoid hyperplasia and thus prevent loss of T-cell functions by preventing numeric dilution of normal T cells by defective T cells. The inability of the unique subset of T cells to respond to antigenic signals cannot be corrected by the addition of interleukin 2 (IL-2), implying that additional cellular properties are required to initiate proliferation. While the vast majority of freshly harvested MRL-lpr T cells lack IL-2 receptors (R) as measured by anti-IL-2R monoclonal antibody staining, a large fraction of nonstimulated, cultured (48 hr) MRL-lpr T cells, but not MRL-++ T cells, express IL-2R. These experiments suggest that MRL-lpr cells are activated in vivo but an undefined suppressive influence prevents detection or expression of IL-2R until these cells are explanted and cultured.

Effect of indomethacin and benoxaprofen on immune complex interaction with cultured glomerular cells

Prostaglandins of the E series (PGE) increased immune complex (IC) interaction with cultured glomerular cells in a previous study. The present study examines the effect of indomethacin (IND) and benoxaprofen (BEN) on interaction of IC with cultured cells and their effect on PGE enhanced cell-IC interaction. IC were formed with antigen modified to produce a cationic (CAT) charge or left unmodified (UM). IND increased cell interaction with IC formed with CAT antigen (CAT IC). BEN had no effect on the interaction of IC formed with either antigen. The combined use of IND and PGE increased CAT IC interaction to the same degree as when each was used alone. BEN prevented the increased CAT IC interaction produced by IND or PGE when used in combination. Protamine sulfate prevented the enhanced CAT IC interaction produced by IND or PGE while sodium heparin had no effect. The results indicate IND and PGE increase cell IC interaction, the increase is not additive when they are combined, the effects of both are blocked by BEN, and protamine sulfate inhibits the effects of both compounds.

Effect of prostaglandins on immune complex interaction with glomerular cells in vitro

Previous studies demonstrated that prostaglandins of the E1 (PGE1) series reduced immune complex (IC) accumulation and inflammation in murine glomeruli in IC glomerulonephritis (GN). This study examines the effect of PGE1 on IC interaction with cultured rabbit glomerular cells and heparan sulfate synthesis by the cells. IC were formed with antigen chemically modified to produce a cationic (CAT) charge or left unmodified (UM). CAT IC binding to cells was greater than UM IC in the absence of PGE1. CAT IC binding to cells was increased by PGE1 while UM IC interaction was not affected. Prolonged exposure of cells to PGE1 enhanced CAT IC binding. Heparan sulfate synthesis by the cells was not affected by the concentrations of PGE1 employed. The findings suggest the benefit provided by PGE1 in murine IC GN may not be due to a direct effect on glomerular cells which reduces glomerular IC accumulation.

Alterations in serum antibody and peripheral T-lymphocyte subsets resulting from treatment of murine immune complex glomerulonephritis with PGE2

The effects of treatment with 16,16-dimethyl prostaglandin E2 (DMPGE2) on histologic damage, glomerular immune complex deposition, serum total IgG subclass levels, anti-apoferritin IgG levels, and peripheral blood T-lymphocyte subsets were determined in apoferritin-induced immune complex glomerulonephritis of mice. The results demonstrate that doses of DMPGE2 ranging from 2.5 to 10 micrograms twice daily significantly reduced the degree of glomerular damage in a dose-dependent manner. Similarly, these doses of DMPGE2 reduced the amount of immunoglobulin deposition along peripheral capillary loops. Total IgM, IgG1, IgG2a, and IgG2b were unaffected by DMPGE2 administration. Serum anti-apoferritin IgG levels were significantly reduced in mice receiving DMPGE2 at doses of 5 and 10 micrograms twice daily. Nephrotic mice had significantly reduced peripheral blood total T lymphocytes (Lyt-1+) and a reduction of T-suppressor (Lyt-2+) cells. Administration of DMPGE2 at doses of 5 and 10 micrograms twice daily prevented these T-lymphocyte alterations. These studies indicate that treatment of mice receiving apoferritin with DMPGE2 may prevent glomerulonephritis by altering both cellular and humoral immune responses.

Effect of mizoribine on lupus nephropathy of New Zealand black/white F1 hybrid mice

Therapeutic trials with mizoribine (MZR), an imidazole nucleoside immunosuppressant, on experimental lupus nephropathy of NZB/W F1 mice resulted in the following. The MZR treatment, 20 mg per kilogram of body weight every other day, starting at 14 weeks of age, caused a significantly prolonged survival time of mice with a mean life span of 54.3 +/- 4.2 weeks, compared with the untreated controls, who had a mean survival time of 38.1 +/- 2.9 weeks (P less than 0.01). In addition, MZR suppressed the elevation of serum anti-DNA antibody titers, the spontaneous development of splenomegaly, and the histological development and progression of glomerulonephritis observed in untreated animals. Although no definite explanation is available at present to explain how MZR caused decreased anti-DNA antibody production and delay in the development of glomerulonephritis in these animals, it is suggested that it acts by directly suppressing the hyperfunctioning B cells of lupus mice. MZR may prove to be a promising immunosuppressant for the treatment of human lupus, in view of its lesser side effects such as bone marrow suppression or hepatotoxicity.

Quantitative variation in la antigen expression plays a central role in immune regulation

The analysis of la antigen function has focused primarily on allelic variants of Ia molecules. In this review Charles Janeway and his colleagues discuss evidence that quantitative rather than qualitative variation in Ia antigen expression had a major role in immunoregulation and immunologically mediated disease.

Prostaglandin synthesis inhibitors and primary antibody response in experimental nephrotic syndrome

The effect of prostaglandin (PG) synthesis inhibitors on the primary antibody response to sheep red blood cells (SRBC) in rats with aminonucleoside-of-puromycin (AP) nephrosis was studied. The response to SRBC was determined 5 days after intraperitoneal administration of SRBC by measuring IgM antibody-forming spleen cells (AFC). In nephrotic rats, SRBC were injected when animals were fully nephrotic. A significant decrease in the number of AFC (P less than 0.05) and a significant increase in the plasma concentration of 6-keto-PGF1 alpha (P less than 0.02) were observed in 22 nephrotic rats compared to 24 normal rats. Treatment of nephrotic rats with indomethacin (5 mg/kg per day, 8 rats) and aspirin (200 mg/kg per day, 7 rats) initiated before the development of nephrosis returned the antibody response and the plasma level of 6-keto-PGF1 alpha to normal, while the same treatment in control rats did not alter the antibody response. These data suggest that in AP nephrosis the observed decrease in antibody response to SRBC is likely due to an increase in PG production at the time of immunization.

Effects of oral aspirin and oxaprozin on the development of lupus-like disease in MRL/1 mice

We examined the effects of two prostaglandin synthetase inhibitors, aspirin and oxaprozin, on the development of lupus-like disease in MRL/1 mice. Daily oral administration of 100 mg/kg of these compounds over a period of 3 months significantly reduced thymic lymphoid hyperplasia. In addition, aspirin but not oxaprozin significantly lowered total lymphocyte counts in the peripheral blood. Other drug-related changes, including reduced hyperplasia in the spleen and lymph nodes and an improvement in kidney vasculitis by aspirin, did not reach statistical significance. Neither aspirin nor oxaprozin influenced the circulating levels of anti-ds DNA antibodies or the severity of kidney glomerulonephritis. While the overall effects of these cyclooxygenase inhibitors were not dramatic, the results do indicate that further studies are warranted to determine the precise therapeutic role, if any, for PG-synthetase inhibitors in lupus-like disease.

Preservation of T-lymphocyte activity in autoimmune MRL-lpr mice treated with prostaglandin

MRL-lpr mice display immunoregulatory disturbances which are related to an early massive T-lymphocyte hyperplasia. Features of autoimmunity are rapidly progressive and these animals die from immune complex-mediated glomerulonephritis. Previous studies show that 15 methyl prostaglandin E1 (PGE) treatment in MRL-lpr mice prolongs survival by preventing lymphoproliferation and the subsequent renal disease. The present study indicates that a major activity of this therapy stabilizes several T-cell functions. Both the age-related loss of the autologous mixed-lymphocyte reaction (AMLR) (Ly1+ 2,3- dependent) and the concanavalin A-induced suppressor cell activity (Ly1- 2,3+ dependent) remain intact. It is suggested that PGE preserves these T-cell functions by maintaining a more normal balance of T-cell subsets.