Cholesterol metabolism in acute upper gastrointestinal bleeding, preliminary observations.

Hypocholesterolemia is commonly found in critically ill patients; however, the aetiology of this condition remains unclear. Several clinical studies refer to the possible negative impact of haemodilution on cholesterol (CH) metabolism in acute medical conditions. The aim of this study was to examine the serum CH profile (total CH, LDL and HDL CH) during acute gastrointestinal bleeding which is a life-threatening condition characterised by alterations in lipid metabolism. Serum non-CH sterols (lathosterol, squalene, sitosterol and campesterol) concentrations as markers of CH synthesis and CH absorption were measured at the same time. Twenty-four patients with acute upper gastrointestinal bleeding (UGIB) were measured for these parameters over a 6-day period. The control group was 100 healthy blood donors.We found lower plasma levels of total CH (p < 0.001) and LDL CH (p < 0.05) in patients with UGIB than in the control group. The decreased HDL CH plasma levels in patients were not statistically significant. In addition, patients had significantly lower plasma levels of lathosterol, squalene, campesterol and sitosterol (p < 0.05).Our results showed abnormalities not only in the CH plasma profile, but also in plasma concentrations of non-CH sterols. These findings of alterations in both the CH synthesis and absorption process could be a contributory cause of hypocholesterolemia during acute gastrointestinal bleeding. However, further research is necessary.