Faculty Bibliography

OBJECTIVE: To investigate whether systemic lupus erythematosus (SLE) is accompanied by increased serum nitrite levels, whether active compared with inactive disease is associated with greater nitric oxide (NO) production, and whether endothelial cells or keratinocytes serve as cellular sources of NO by virtue of their increased expression of either constitutive nitric oxide synthase (cNOS) or inducible NOS (iNOS). METHODS: Fifty-one serum samples (46 from patients with SLE) were analyzed for NO production by measuring nitrite levels in a calorimetric assay. Skin biopsy samples from 21 SLE patients and 11 healthy volunteers were evaluated immunohistochemically, using monoclonal antibodies, for endothelial cell and keratinocyte cNOS and iNOS expression. RESULTS: Serum nitrite levels were significantly elevated in the 46 patients with SLE (mean +/- SEM 37 +/- 6 microM/liter) compared with controls (15 +/- 7 microM/liter; P < 0.01), and were elevated in patients with active SLE compared with those with inactive disease (46 +/- 7 microM/liter versus 30 +/- 7 microM/liter; P < 0.01). Serum nitrite levels correlated with disease activity (r = 0.47, P = 0.04) and with levels of antibodies to double-stranded DNA (r = 0.35, P = 0.02). Endothelial cell expression of iNOS in SLE patients (mean +/- SEM score 1.5 +/- 0.2) was significantly greater compared with controls (0.6 +/- 0.2; P < 0.01), and higher in patients with active disease compared with those with inactive SLE (1.7 +/- 0.2 versus 1.2 +/- 0.2; P < 0.01). Keratinocyte expression of iNOS was also significantly elevated in SLE patients (0.9 +/- 0.1) compared with controls (0.4 +/- 0.1; P < 0.001). With regard to expression of cNOS, there were no differences between patients with active SLE, those with inactive SLE, and normal controls in either the vascular endothelium or the keratinocytes. CONCLUSION: NO production is increased in patients with SLE, and 2 potential sources of excessive NO are activated endothelial cells and keratinocytes via up-regulated iNOS

Fourteen patients were enrolled in a placebo-controlled double-blind randomized trial of 8 weeks of treatment for active lupus nephritis. Seven patients received prednisone at a dose of 1 mg kg(minus sign1) day(minus sign1) plus misoprostol at a dose of 200 &mgr;g P.O. Q.I.D.; 7 patients received prednisone plus placebo. The patients included 12 females, 2 males; 3 African-Americans, 3 Asians, 5 Hispanics, and 3 Caucasians. There were no serious side effects associated with prednisone or misoprostol treatment during the 8-week study period. Laboratory measures obtained at baseline, 4, 8, and 12 weeks included complete blood count (CBC), ESR, C reactive protein (CRP), serum creatinine, creatinine clearance, 24-h urine protein excretion, C3, C4, and anti-double stranded DNA (anti-dsDNA). Statistical analysis was conducted assessing change in measures over time in the entire study group by paired t-tests. The effect of treatment on change over time was examined by analysis of covariance. Log transformation of the variables was performed prior to statistical analysis. For the entire study group, the mean levels of ESR, CRP, 24-h protein excretion, C3, C4, and anti-dsDNA were improved at 4, 8, and 12 weeks. The mean ESR at baseline was 70 plus minus 8 compared to 42 plus minus 8 at 12 weeks (p < 0.01). The mean CRP at baseline was 0.6 plus minus 0.2 compared to 0.2 plus minus 0.1 at 12 weeks (p < 0.01). The 24-h protein excretion was 4367 plus minus 769 mg at baseline compared to 2512 plus minus 709 mg at 12 weeks (p = 0.02). The mean C3 at baseline was 40 plus minus 4 mg dl(minus sign1) compared to 60 plus minus 4 mg dl(minus sign1) at 12 weeks (p < 0.01). The mean C4 at baseline was 14 plus minus 1 mg dl(minus sign1) compared to 23 plus minus 2 mg dl(minus sign1) at 12 weeks (p < 0.01). The mean anti-dsDNA at baseline was 4268 plus minus 1780 compared to 316 plus minus 111 at 12 weeks (p < 0.001). The baseline serum creatinine (1.12 plus minus.15 mg dl(minus sign1)) and creatinine clearance (82 plus minus 15 ml min(minus sign1)) were not significantly changed at 12 weeks (1.10 plus minus 0.2 mg dl(minus sign1) and 80 plus minus 17 ml min(minus sign1), respectively). Comparing the misoprostol treatment group to the placebo group, there were no statistically significant differences for ESR, CRP, creatinine, creatinine clearance, 24-h protein excretion, C3, C4, or anti-dsDNA at any time points. However, comparing the misoprostol treatment group at 4 weeks to the placebo group, a more rapid decrease in anti-dsDNA (reduction of 3297 plus minus 2374) was observed in the misoprostol treatment group versus 304 plus minus 409 in the placebo group), as well as lower mean anti-dsDNA levels (464 plus minus 140) in the misoprostol treatment group versus 4118 plus minus 3834 in the placebo group). Also, the C3 and C4 levels at 12 weeks in the misoprostol treatment group (67 plus minus 5 and 27 plus minus 3 mg dl(minus sign1), respectively) were greater than levels in the placebo group (52 plus minus 4 and 19 plus minus 3 mg dl(minus sign1), respectively). The data demonstrate that oral prednisone is effective in reducing proteinuria and improving the biological markers of disease activity (i.e., ESR, CRP, C3, C4, and anti-dsDNA) following short-term treatment of active lupus nephritis. Additionally, the more rapid change in anti-dsDNA levels and superior normalization of complement levels in the treatment group, although not statistically significant, are consistent with a biologic effect of misoprostol on lymphocyte function and the production of a pathogenic autoantibodies