Oxidative stress in kidney transplant biopsies.

OBJECTIVES: Kidney allograft biopsies are performed after kidney transplant to determine graft dysfunction. We aimed to define and measure the oxidative stress occurring in these biopsies and compared these biopsies with donor pretransplant biopsies. MATERIALS AND METHODS: The biopsy procedure was done according to the unit protocol. A core of tissue was taken for research purposes only when it was safe enough to proceed for an extra core. Common indications for biopsy were acute or chronic graft dysfunction, delayed graft function, acute cellular rejection, and calcineurin toxicity. There were 17 pretransplant biopsies taken from deceased-donor kidneys. Biopsy specimens were snap frozen immediately in liquid nitrogen and stored at -70 °C. Samples were processed for Western blot and tested for markers of oxidative stress. RESULTS: There were 61 biopsies analyzed. Oxidative stress enzymes were evaluated by Western blot including catalase, manganese superoxide dismutase, copper zinc superoxide dismutase, thioredoxin reductase, and thioredoxin. Upregulation of most antioxidant enzymes was observed in pretransplant biopsies. Increased expression of manganese superoxide dismutase was observed in donor kidneys and kidneys with acute cellular rejection and calcineurin toxicity. Copper zinc superoxide dismutase and catalase were elevated in donor and acute cellular rejection biopsies. Thioredoxin was elevated in donor biopsies and thioredoxin reductases were elevated in donor biopsies and biopsies with acute cellular rejection and calcineurin toxicity. CONCLUSIONS: The kidney allograft biopsies showed that oxidative stress levels were elevated during allograft dysfunction in all biopsies regardless of diagnosis, but not significantly. The levels also were elevated in pretransplant biopsies. The study showed that oxidative stress is involved in various acute injuries occurring within the allograft.

Randomised placebo-controlled trial of rituximab (anti-CD20) in active ulcerative colitis.

OBJECTIVE: To assess the safety and efficacy of the B lymphocyte (anti-CD20) antibody, rituximab, in the treatment of steroid-resistant moderately active ulcerative colitis (UC). METHODS: A double-blinded, randomised controlled trial with a 2:1 ratio of treatment:placebo (phase II) was carried out in the setting of a University teaching hospital. The subjects comprised 24 patients with moderately active UC who have either failed to respond to conventional corticosteroid therapy or who have relapsed during corticosteroid withdrawal. Five of 8 placebo-treated patients and 12 of 16 rituximab-treated patients were receiving azathioprine, 6-mercaptopurine or methotrexate. Two infusions of rituximab 1 g in 500 ml of 0.9% saline intravenously over 4 h (n=16) or saline placebo (n=8) were given at 0 and 2 weeks. Patients still receiving corticosteroids on entry (placebo group 7/8; rituximab group 14/16) continued a standard steroid tapering regimen. The primary end point was remission (Mayo score ≤ 2) at 4 weeks. Secondary end points included response (Mayo score reduced ≥ 3) at 4 and 12 weeks. RESULTS: Mayo score at entry was higher in rituximab-treated patients (mean 9.19; 95% CI 8.31 to 10.06) than for placebo patients (7.63; 6.63 to 8.62, p=0.03). At week 4 only 1/8 placebo-treated patients and 3/16 rituximab-treated patients were in remission (p=1.0), but 8/16 rituximab-treated patients had responded compared with 2/8 placebo-treated patients, with a median reduction in Mayo score of 2.5 (rituximab) compared with 0 (placebo; p=0.07). This response was only maintained to week 12 in 4/16. Mucosal healing was seen at week 4 in 5/16 rituximab-treated patients and 2/8 placebo-treated patients (non-significant). Rituximab was well tolerated, with one chest infection, three mild infusion reactions plus one case of (probably unrelated) non-fatal pulmonary embolism. CONCLUSIONS Rituximab has no significant effect on inducing remission in moderately active UC not responding to oral steroids. There was a possible short-term response that was not sustained. Rituximab is well tolerated in UC. CLINICAL TRIAL NUMBER: NCT00261118.