Established murine lupus nephritis does not respond to exogenous interleukin-1 receptor antagonist; a role for the endogenous molecule?
Interleukin 1 beta (IL-1 beta) is a potent inflammatory cytokine and IL-1 beta gene expression is elevated in the kidneys of mice with lupus nephritis. This study was designed to examine whether pharmacological administration of the IL-1 receptor antagonist (IL-1ra) would reduce the inflammation in MRL lpr/lpr mice with lupus nephritis. Human recombinant IL-1ra (RA) or saline (SA) was infused by intraperitoneal osmotic minipumps in 16 week old mice (n = 9, group RA or n = 12, group SA, respectively). Age matched MRL +/+ mice served as normal controls. At the end of 4 weeks of treatment glomerular filtration rates (5.4 +/- 0.4 vs 5.6 +/- 0.4 ml/min/kg BW), proteinuria (6.0 +/- 1.0 vs 5.5 +/- 1.2 micrograms IgG/day) glomerular volumes (571 +/- 30 vs 509 +/- 25 microns3 x 10(3)), mesangial volumes (172 +/- 23 vs 158 +/- 17 microns3 x 10(3)), and cells/glomerulus (519 +/- 51 vs 506 +/- 47) were not significantly different between RA and SA groups respectively. There was also no significant differences in spleen sizes, plasma IgG and anti-dsDNA antibody levels despite achieving levels of IL-1ra of over 0.8 microgram/ml in RA mice. Circulating IL-1 was not detected by bioassay in the plasma of diseased or normal mice. In fact, diseased, saline treated mouse plasma inhibited the cell proliferation assay in the presence of IL-1, and dilution studies showed that the endogenous inhibitors were of high titre. Although IL-1 may play a role in the renal injury of lupus nephritis, pharmacological inhibition with IL-1ra in animals with established injury is without effect.(ABSTRACT TRUNCATED AT 250 WORDS)
Kiberd
B A
BA
Department of Medicine, Dalhousie University, Halifax, N.S., Canada.
Stadnyk
A W
AW
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007668:Kidney / Q000187:drug effects / Q000503:physiopathology; D007678:Kidney Glomerulus / Q000473:pathology; D008181:Lupus Nephritis / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*; D051379:Mice; D008817:Mice, Mutant Strains; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000494:pharmacology; D012795:Sialoglycoproteins / Q000494:pharmacology* / Q000502:physiology*
C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins; D012795:Sialoglycoproteins