Efecto de la ingesta de vitamina C en el proceso de formación de cálculos biliares de colesterol / Effects of vitamin C administration on cholesterol gallstone formation

Background: Biliary cholesterol is transported by vesicles and micelles. Cholesterol microcrystals are derived from thermodynamically unstable vesicles. In experimental animals vitamin C deficiency leads to a super-saturation of biliary cholesterol and to the formation of gallstones. Aim: To search for a possible relationship between serum levels of vitamin C and the formation of cholesterol gallstones in patients with cholelithiasis. Material and Methods: Thirteen patients with cholelithiasis and a programmed surgical intervention were treated with 2 g/day of vitamin C per os for two weeks before surgery. Forty nine patients subjected to a cholecystectomy not supplemented with vitamin C were studied as controls. Plasma concentrations of vitamin C and lipid profiles were measured. The cholesterol saturation index, crystallization time, cholesterol and phospholipid content in vesicles and micelles, separated by gel filtration chromatography, were studied in bile samples obtained from the gallbladder. Results: Vitamin C supplementation did not change significantly plasma lipids and bile lipid concentrations. However, in supplemented patients, significant reductions in vesicular cholesterol content (6.5 ± 4.8% compared to 17.9 ± 14.0% in the control group; p < 0.05) and vesicular cholesterol/phospholipid ratio (0.71 ± 0.53 compared to 1.36 ± 1.15 in controls; p < 0.05), were observed. Conclusions: Vitamin C administration may modify bile cholesterol crystallization process, the first step in cholesterol gallstone formation.

Tratamiento en pacientes operados de estómago con ácidos biliares elevados y Helicobacter pylori positivo / Treatment in patients operated on of the stomach with elevated biliary acids and positive Helicobacter pylori

Se realizó un estudio del tipo experimental, no ciego y aleatorizado, constituido por 30 pacientes adultos de uno y otro sexos con diagnóstico de gastritis crónica alcalina por reflujo duodenogástrico, en resecados de estómago (Billroth I, Billroth II), mediante endoscopia superior, con ácidos biliares totales elevados y Helicobacter pylori positivo. Estos pacientes se distribuyeron en 2 grupos de tratamiento durante 8 semanas. El grupo A, de 15 pacientes, recibió tratamiento con: subcitrato de bismuto coloidal (Q-ulcer), metronidazol y tetraciclina, más ranitidina como antihistamínico H2. El grupo B, de 15 pacientes, se le administró celulosa microcristalina (Microcel). Ambos grupos recibieron metoclopramida como fármaco procinético durante todo el tratamiento. Los índices de erradicación de la infección por H. pylori fueron del 46,7 por ciento para el grupo A y del 42,9 por ciento para el grupo B. La concentración de ácidos biliares totales al final del tratamiento disminuyó en el 53,3por ciento de los pacientes del grupo A y en el 71,4 por ciento de los pacientes del grupo B. La concentración de ácidos biliares totales en el remanente gástrico al final del tratamiento, no influyó en la evaluación clínica, endoscópica e histológica de los pacientes en ambos esquemas de tratamiento. No se presentaron efectos adversos secundarios en los pacientes del grupo A y 1 paciente (6,6 por ciento) del grupo B abandonó el estudio al empeorar su cuadro clínico, el cual fue intervenido quirúrgicamente, por lo que se considera fracaso del tratamiento. Se concluye que estos esquemas terapéuticos no fueron eficaces.

A non-blind randomized experimental study was undertaken. It included 30 adults of both sexes with diagnosis of alkaline chronic gastritis due to duodenogastric reflux, in stomach resections (Billroth I, Billroth II), by upper endoscopy, with elevated total biliary acids and positive Helicobacter pylori. These patients were divided into 2 groups of treatment during 8 weeks. The group A was composed of 15 patients and received treatment with colloidal bismuth subcitrate (Q-ulcer), metronidazole and tetracycline, plus ranitidine as H2 antihistaminic. The group B was made up of 15 patients and it was administered microcrystalline cellulose (Microcel). Metoclopramide was given to both groups as a prokinetic drug during the whole treatment. The indexes for the eradication of H. pylori infection were 46.7 percent for group A, and 42.9 percent for group B. The concentration of total biliary acids at the end of the treatment decreased in 53.3 percent of the patients from group A and in 71.4 percent in group B. The concentration of total biliary acids in the gastric residue at the end of the treatment did not influence on the clinical, endoscopic and histological evaluation of the patients in both treatment schemes. No adverse secondary effects were observed in the patients from group A. One patient (6.6 percent) from group B left the study because its clinical picture got worse. He underwent surgery and it was considered a failure of the treatment. It was concluded that these therapeutic schemes were not efficient.

Visión filogenética de los ácidos biliares / Phylogenic diversity of bile acids

Bile acids are the most important solutes of bile; they are essential in cholesterol degradation, solubilization and excretion; they are determinants of bile flow and secretion and their role is crucial in the intestinal absorption of lipids and lipid soluble vitamins. In amphibia and in cartilaginous fish, the 27C cholestane molecule is hydroxylated to vertebrates of a more recent evolutionary origin, the lateral chain is shortened to 24C and oxydated to cholestanoic acids. Further transformations include chemical changes in the cholestane skeleton and in the lateral chain (hydroxylations, dehydroxylations, epimerization, etc.) Inthe intestinal lumen, the saprophytic flora provides enzymes catalysing new changes that originate secondary bile acids. During entero-hepatic circulation, another variety of bile acids appear, commonly termed tertiary bile acids. A recet study of Lee R Hagey characterized bile acid composition of over 600 species of vertebrates, showing that bile acid composition of bile has been the subject of an interesting evolutionary phenomenon and that it is a chemical marker of biodiversity in vertebrates