Discrepancies between effects of recombinant human growth hormone on absorption and secretion of water and electrolytes on the human jejunum compared to results reported on rat jejunum

Total parenteral nutrition-related gastroenterological complications

Total parenteral nutrition is a life saving therapy for patients with chronic gastrointestinal failure, being an effective method for supplying energy and nutrients when oral or enteral feeding is impossible or contraindicated. Clinical epidemiological data indicate that total parenteral nutrition may be associated with a variety of problems. Herein we reviewed data on the gastroenterological tract regarding: (i) total parenteral nutrition-related hepatobiliary complications; and (ii) total parenteral nutrition-related intestinal complications. In the first group, complications may vary from mildly elevated liver enzyme values to steatosis, steatohepatitis, cholestasis, fibrosis and cirrhosis. In particular, total parenteral nutrition is considered to be an absolute risk factor for the development of biliary sludge and gallstones and is often associated with hepatic steatosis and intrahepatic cholestasis. In general, the incidence of total parenteral nutrition-related hepatobiliary complications has been reported to be very high, ranging from 20 to 75% in adults. All these hepatobiliary complications are more likely to occur after long-term total parenteral nutrition, but they seem to be less frequent, and/or less severe in patients who are also receiving oral feeding. In addition, end-stage liver disease has been described in approximately 15-20% of patients receiving prolonged total parenteral nutrition. Total parenteral nutrition-related intestinal complications have not yet been adequately defined and described. Epidemiological studies intended to define the incidence of these complications, are still ongoing. Recent papers confirm that in both animals and humans, total parenteral nutrition-related intestinal complications are induced by the lack of enteral stimulation and are characterised by changes in the structure and function of the gut. Preventive suggestions and therapies for both these gastroenterological complications are reviewed and reported in the present review.

Oral rehydration therapy: new explanations for an old remedy

Diarrheal diseases are among the most devastating illnesses globally, but the introduction of oral rehydration therapy has reduced mortality due to diarrhea from >5 million children, under the age of 5, in 1978 to 1.3 million in 2002. Variations of this simple therapy of salts and sugars are prevalent in traditional remedies in cultures world-wide, but only in the past four decades have the scientific bases for these remedies begun to be elucidated. This review aims to provide a broad understanding of the cellular basis of oral rehydration therapy. The features integral to the success of oral rehydration therapy are active glucose transport in the small intestine, commensal bacteria, and short-chain fatty acid transport in the colon. The review examines these processes and their regulation and considers new approaches that might supplement oral rehydration therapy in controlling diarrheal diseases.

Effect of octreotide on fluid absorption and secretion by the normal human jejunum and ileum in vivo

BACKGROUND

We hypothesized that part of the non-specific antidiarrhoeal effect of octreotide is mediated by a proabsorptive or antisecretory effect on small intestinal active electrolyte transport.

METHODS

To measure the effect of octreotide on net absorption, the jejunum and ileum of normal human subjects were perfused with a balanced electrolyte solution; to measure the effect of octreotide on normal active chloride secretion, the jejunum was perfused with a bicarbonate-free solution.

RESULTS

During perfusion of a balanced electrolyte solution, octreotide increased basal net fluid absorption in the jejunum and ileum by about 40 mL/h per 30 cm. In the jejunum, octreotide markedly inhibited basal and sham feeding-stimulated active chloride secretion and inhibited water secretion by 28 and 51 mL/h per 30 cm, respectively.

CONCLUSIONS

Octreotide causes an increase in the net epithelial cell absorption rate of a balanced electrolyte solution in the normal jejunum and ileum. In the jejunum, this proabsorptive effect is mediated mainly by the reduction of normal active electrolyte secretion, rather than by stimulation of normal active electrolyte absorption. These results support the hypothesis that part of the antidiarrhoeal action of octreotide is due to its effects on active electrolyte transport mechanisms by normal epithelial cells of the small intestine.