The development of gastric cancer is a multi-factor process. In addition to genetic factors, environmental factors including smoking, low gastric acidity, excessive intake of salt or salty food and low consumption of fresh fruits and vegetables all contribute to the development of gastric cancer. Of particular interest, epidemiological and experimental studies have demonstrated that Helicobacter pylori (H. pylori) infection is causally linked to gastric cancer. Most studies using micronutrient supplementation have failed to demonstrate any preventive effect against the development of gastric cancer. The use of non-steroidal anti-inflammatory drugs has been consistently observed to protect against the development of gastric cancer. Recently, eradication of H. pylori infection by a chemopreventative approach is being studied in a number of trials. Studies using precancerous lesions as an end point of the treatment have produced conflicting and mostly negative results. Trials using cancer as an end point are being cautiously carried out in high-risk populations, and will provide the definitive answer to this important question. In the end, vaccination may be proven to be the optimal strategy in human for the management of H. pylori infection and prevention of gastric cancer.
Anti-Inflammatory Agents, Non-Steroidal ; therapeutic use ; Anticarcinogenic Agents ; therapeutic use ; Dietary Supplements ; Helicobacter Infections ; complications ; drug therapy ; prevention & control ; Humans ; Stomach Neoplasms ; etiology ; prevention & control ; Vaccination

BACKGROUNDThe contractility of hepatic stellate cells (HSCs) may play an important role in the pathogenesis of cirrhosis with portal hypertension. The aim of this study was to research the effects of octreotide, an analogue of somatostatin, on intracellular Ca2+ and on the expression of L-type voltage-operated calcium channels (L-VOCCs) in activated HSCs, and to try to survey the use of octreotide in treatment and prevention of cirrhosis with portal hypertension complications.

METHODSHSC-T6, an activated HSCs line, was plated on small glass coverslips in 35-mm culture dishes at a density of 1 x 10(5)/ml, and incubated in DMEM media for 24 hours. After the cells were loaded with Fluo-3/AM, intracellular Ca2+ was measured by Laser Scanning Confocal Microscopy (LSCM). The dynamic changes in activated HSCs of intracellular Ca2+, stimulated by octreotide, endothelin-1, and KCl, respectively, were also determined by LSCM. Each experiment was repeated six times. L-VOCC expression in HSCs was estimated by immunocytochemistry.

RESULTSAfter octreotide stimulation, a significant decrease in the intracellular Ca2+ of activated HSCs was observed. However, octreotide did not inhibit the increases in intracellular Ca2+ after stimulation by KCl and endothelin-1. Moreover, octreotide did not significantly affect L-VOCC expression. These results suggest that neither L-VOCC nor endothelin-1 receptors in activated HSCs are inhibited by octreotide.

CONCLUSIONSOctreotide may decrease portal hypertension and intrahepatic vascular tension by inhibiting activated HSCs contractility through decreases in intracellular Ca2+. The somatostatin receptors in activated HSCs may be inhibited by octreotide.

Calcium ; analysis ; Calcium Channels, L-Type ; analysis ; Cells, Cultured ; Hepatocytes ; chemistry ; cytology ; drug effects ; Microscopy, Confocal ; Octreotide ; pharmacology