Effect of zinc supplementation on superoxide dismutase activity in patients with ulcerative rectocolitis.

INTRODUCTION: Ulcerative rectocolitis is characterized by diffuse mucosal inflammation and oxidative stress. Thus, the organism activates the antioxidant defence system in an attempt to reduce the excessive production of reactive oxygen species or neutralize them. OBJECTIVE: This study evaluated the effect of zinc supplementation on the activity of the enzyme superoxide dismutase (SOD) in patients with ulcerative rectocolitis. METHODS: The study included 24 patients, aged between 20 and 59 years and diagnosed with ulcerative rectocolitis, in the remission stage of the disease, who were divided into two groups: experimental - deficient in zinc (n=12) and control - normal or high zinc (n=12). Only the first group underwent supplement intervention, in the form of zinc gluconate (30 mg Zn/day), taken daily in the morning, fasted for 60 days. Plasma and erythrocyte zinc concentrations were determined by flame atomic absorption spectrophotometer. The erythrocyte SOD activity was determined in vitro according to the methodology recommended by the manufacturer Randox. RESULTS AND DISCUSSION: Zinc supplementation caused a significant increase in the plasma concentrations of the mineral, and showed a significant reduction in erythrocyte zinc, remaining within normal limits. The SOD activity was high in patients of both the experimental and control groups, with no difference after supplementation. CONCLUSION: This study demonstrates that zinc supplementation improves the homeostatic condition of the mineral, with no change in SOD activity, as a marker of oxidative stress in patients with ulcerative rectocolitis.

Introducción: La colitis ulcerosa se caracteriza por la inflamación difusa de la mucosa y el estrés oxidativo. De esta forma, el cuerpo activa el sistema de defensa antioxidante en un intento de reducir la producción excesiva de especies reactivas de oxígeno, así como poder neutralizarlos. Objetivo: Este estudio evaluó el efecto de la suplementación de zinc sobre la actividad de la enzima superóxido dismutasa en pacientes con colitis ulcerosa. Métodos: El estudio incluyó 24 pacientes, con edades comprendidas entre 20 y 59 años y con diagnóstico de colitis ulcerosa en fase de remisión de la enfermedad. Los pacientes fueron divididos en dos grupos: experimental - deficiencia de zinc (n = 12) y control - normales o con altos contenido de zinc (n = 12). El grupo experimental se sometió a tratamiento con suplemento de drogas, en forma de gluconato de zinc (30 mg Zn / día), administrada diariamente por la mañana en ayunas durante 60 días. Las concentraciones en plasma y los eritrocitos de zinc se determinaron por espectrofotometría de absorción atómica de llama. La actividad de la superóxido dismutasa (SOD) se determinó por el método de eritrocitos in vitro utilizando el kit de Randox. Resultados y Discusión: La suplementación de zinc causó un aumento significativo en las concentraciones plasmáticas de mineral y mostró una reducción significativa en los eritrocitos, permaneciendo dentro de los límites normales. La actividad de SOD fue mayor en los pacientes de los grupos experimentales y de control, sin diferencias después de la suplementación. Conclusión: El estudio evidenció que la administración de suplementos de zinc mejora la condición homeostática del mineral, sin ningún cambio en la actividad de SOD, como un marcador de estrés oxidativo en pacientes con colitis ulcerosa.

[Adenomatous and inflammatory colorectal polyps: antioxidative enzyme activity in the colon]. / Adenomatózne a zápalové polypy kolorekta: aktivita antioxidacných enzýmov v kolone.

BACKGROUND: Reactive types of oxygen play an important part also in carcinogenesis. Antioxidant enzymes are the primary defence against their damage. The objective of the present work was to glutathione peroxidase in the mucosa and polyps of the colon in subjects with colorectal adenoma and idiopathic proctocolitis. METHODS AND RESULTS: The authors examined 18 controls, 43 patients with colorectal adenoma and 12 subjects with idiopathic proctocolitis. During endoscopy bioptic specimens of the mucosa and from polyps were taken for histological and enzymological examination: Cu/Zn superoxide dismutase, catalase, glutathione peroxidase. In subjects with colorectal adenoma a raised glutathione peroxidase activity was found in the colon and an elevated activity of superoxide dismutase in the adenoma. In patients with idiopathic proctocolitis in the stage of clinical remission in the mucosa a lower glutathione peroxidase activity was found but a high activity of all enzymes was recorded in the inflamed polyps. CONCLUSIONS: The cause of elevated activities of antioxidant enzymes in subjects with colorectal adenoma in the colonic mucosa and in adenomas is not known and calls for further studies. In patients with idiopathic proctocolitis the increased level of antioxidant enzymes in the mucosa is probably produced by a higher production of reactive oxygen types by activated leucocytes in the inflamed tissues.

Mucosal glucosamine synthetase activity in inflammatory bowel disease.

Abnormalities in colonic glycoprotein synthesis have been implicated in the pathogenesis of ulcerative colitis and Crohn's disease. Glucosamine synthetase is the rate-limiting step in the biosynthesis of gastrointestinal glycoprotein and has been measured in control subjects (N = 23) and patients with ulcerative colitis (N = 26) or Crohn's disease of the colon (N = 20) classified according to the macroscopic status of the rectum. Glucosamine synthetase activity was relatively constant around the normal colon but lower levels were found in the terminal ileum. In ulcerative colitis, glucosamine synthetase activity was similar to controls (24.0 +/- 1.9) mmol/g wet (wt/hr) irrespective of disease activity (quiescent: N = 13, = 27.3 +/- 1.9; active N = 16, = 26.2 +/- 2.3). Rectal glucosamine synthetase activity was normal in the presence of active Crohn's proctocolitis (29.4 +/- 3.1) but raised in patients with Crohn's colitis and rectal sparing (37.2 +/- 4.9 P < 0.02). Glucosamine synthetase activity was strongly influence by the degree of epithelial preservation.