Splanchnic exchange of glucose, amino acids and free fatty acids in patients with chronic inflammatory bowel disease

Abstract

In order to study arterial concentrations and splanchnic exchange of substrates and hormones in patients with chronic inflammatory bowel disease three patients with Crohn's disease and four with ulcerative colitis were studied using the hepatic venous catheter technique. Systemic turnover and regional exchange of free fatty acid were evaluated using intravenous infusion of 14C-labelled oleic acid. All measurements were made in the postabsorptive, overnight fasted state. Arterial glucose concentrations were 10% lower in the patients but net splanchnic glucose output was similar in patients and controls. Glucose precursor uptake (lactate, pyruvate, and glycerol), however, was increased two to five fold in the patients. Arterial amino acid concentrations were generally reduced but net splanchnic amino acid uptake was the same in patients and controls. Arterial concentrations of free fatty acid and oleic acid as well as systemic and fractional turnover were similar in patients and controls. The patients' splanchnic uptake of oleic acid was increased more than three fold in comparison with controls. Splanchnic release of oleic acid was also augmented in the patients. Both arterial concentrations and splanchnic production of ketone bodies were raised in the patients. The proportion of splanchnic free fatty acid uptake which could be accounted for by ketone body production was significantly greater in the patients (37 +/- 4%) than the controls (20 +/- 5%, p less than 0.025). Estimated hepatic blood flow was 55% greater (p less than 0.01) in the patients as compared with the controls (1930 +/- 150 vs 1240 +/- 70 ml/min), while splanchnic oxygen uptake was similar in the two groups. From these findings it is concluded that patients with chronic inflammatory bowel disease show (1) markedly increased hepatic blood flow, reflecting an inflammatory hyperaemia in the splanchnic region, (2) a normal net splanchnic glucose output, (3) accelerated hepatic gluconeogenesis as well as ketogenesis, probably as a consequence of the altered hormonal milieau, and (4) low concentrations of most amino acids possibly because of protein malabsorption. These findings underscore the importance of adequate protein and carbohydrate administration to this patient group.