Nonimmunological alterations of glomerular filtration by s-PAF in the rat kidney

Nonimmunological alterations of glomerular filtration by s-PAF in the rat kidney. Rat kidneys were isolated and perfused with a cell-free perfusion buffer containing 4% albumin. Infusion of platelet activating factor (s-PAF) into the isolated perfused kidney caused a dose-dependent fall in renal vascular resistance (RVR): 12 ± 6% at 10nM s-PAF, 18 ± 3% at 100nM s-PAF and 20 ± 7% at 1 µM. s-PAF. Glomerular filtration rate fell by 32 ± 5% at 10nM, 38 ± 6% at 100nM, and 52 ± 10% at 1 µM. s-PAF (50nM) increased urinary protein excretion after 20 minutes. Because GFR fell to a greater extent than RVR, possible changes in glomerular permeability after s-PAF treatment were assessed morphologically using native ferritin. After s-PAF treatment (100nM), the number of ferritin particles/µm2 increased from 1.2 ± 0.9 (control) to 795 ± 69 in the glomerular basement membrane (GBM) and from 0.2 ± 0.06 (control) to 98 ± 29 in lamina rara externa (LRE). To quantitate changes in fixed anionic charges, polyethylenimine (PEI) was quantitated morphologically in GBM. No significant change between s-PAF treated and untreated kidneys was seen. s-PAF did not alter the sialoglycoprotein pattern in the perfused kidney as assessed by lysozyme staining. These results are in contrast to findings with s-PAF in vivo where in addition to increased glomerular permeability, a reduction of fixed anionic charges is seen. Thus, these results help to differentiate a dual mechanism of s-PAF: 1) a direct action of s-PAF on glomerular epithelial and vascular cells and, 2) an indirect action of s-PAF on glomerular structures via stimulation of release of inflammatory mediators from circulatory cells

Results of a phase-I/II randomized, masked, placebo-controlled trial of recombinant human interleukin-11 (rhIL-11) in the treatment of subjects with active rheumatoid arthritis

Interleukin-11 (IL-11) is a pleiotropic cytokine that regulates the growth and development of hematopoietic stem cells and decreases the proinflammatory mediators of cytokine and nitric oxide production. In animal models of arthritis, treatment with recombinant human IL-11 (rhIL-11) reduces both the level of synovitis and the histologic lesion scores in the joints. The goal of this phase-I/II study in adults with rheumatoid arthritis (RA) was to evaluate the safety and clinical activity of different doses and schedules of rhIL-11 in patients with active RA for whom treatment with at least one disease-modifying antirheumatic drug had failed. This was a multicenter, randomized, placebo-controlled trial that evaluated the safety and tolerability of rhIL-11 in 91 patients with active RA. rhIL-11 was administered subcutaneously; patients were randomized into one of five treatment groups (ratio of rhIL-11 to placebo, 4:1). Patients were treated for 12 weeks with either 2.5 or 7.5 μg/kg of rhIL-11 or placebo twice per week or 5 or 15 μg/kg of rhIL-11 or placebo once per week. The status of each subject's disease activity in accordance with the American College of Rheumatology (ACR) criteria was assessed before, during, and after completion of administration of the study drug. Administration of rhIL-11 was well tolerated at all doses and schedules. The most frequent adverse event was a reaction at the injection site. The data suggest a statistically significant reduction in the number of tender joints (P < 0.008) at the 15 μg/kg once-weekly dose schedule but showed no overall significant benefit at the ACR criterion of a 20% response. The trial showed rhIL-11 to be safe and well tolerated at a variety of doses and schedules over a 12-week treatment period in patients with active RA. The only adverse event clearly associated with rhIL-11 administration was reaction at the injection site