Absorption of glucose polymers from rice in oral rehydration solutions by rat small intestine

Enhancing clinical efficacy of oral rehydration therapy: is low osmolality the key?

Many empirical clinical trials have used complex carbohydrate as substrate in oral rehydration solutions (ORSs) instead of glucose and have shown a number of important clinical benefits. Foremost among these are reduced stool volumes, shorter duration of diarrheal illness, and lower ORS intake. The underlying mechanisms to explain this clinical advantage have not been fully established, but a number of possible factors have been proposed: (1) increased substrate availability, (2) a "kinetic advantage" for glucose absorption by glucose polymer, (3) differential handling of glucose monomer and polymer by the small intestine, (4) low osmolality, (5) a separate effect of peptides and amino acids on solute-linked sodium absorption, (6) an antisecretory moiety in rice, and (6) enhanced mucosal repair and regeneration by luminal nutrients. In this report, we assess the relative contribution of these factors using evidence from laboratory-based studies, mainly in disease-related intestinal perfusion systems in animals and humans, and the relevant clinical studies available to date. We advance the hypothesis that of all the possible mechanisms proposed to underlie the enhanced clinical efficacy of complex carbohydrate ORSs, their hypotonicity plays the dominant role. If confirmed, this concept could guide future development of glucose and complex carbohydrate-based ORSs.

Regional differences in the effect of mucosal glucose and amino acids on ion transport in normal and cholera toxin-stimulated porcine small intestine

BACKGROUND

This study explores regional differences in the response to mucosal D-glucose and L-amino acids in both normal intestine and intestine stimulated with cholera toxin.

METHODS

Proximal, mid and distal small intestines from 6- to 8-week-old pigs were bathed in Ussing chambers with a buffer containing 15 mM serosal glucose, and the effect of adding a cocktail giving luminal chamber concentrations of 15 mM D-glucose and 20 mM of each L-alanine, L-proline, L-lysine, L-phenylalanine, and L-glutamine on transmucosal Na+ and Cl- transport was measured.

RESULTS

In all segments of both normal and cholera toxin-treated intestine, electrogenic Na+ and electroneutral NaCl absorption were promoted. No significant differences in the net increase of Na+ and Cl- absorption between normal and cholera toxin-stimulated intestine were present. Under both conditions no segmental differences were present in the stimulated Cl- absorption, describing identical capacity for stimulated electroneutral NaCl absorption. In contrast the electrogenic Na+ absorption was, compared to the proximal part, doubled in the mid and distal parts under both conditions.

CONCLUSIONS

We conclude that mucosal D-glucose and L-amino acids stimulate electroneutral NaCl and electrogenic Na+ absorption to the same degree in normal and cholera toxin-treated small intestine. There is no segmental difference in stimulated electroneutral NaCl absorption, while electrogenic Na+ absorption is highest in mid and distal parts.

Composition and preliminary evaluation of a hydrolyzed rice-based oral rehydration solution for the treatment of acute diarrhea in children

OBJECTIVE

The purpose of this study was to experimentally develop and clinically evaluate the safety and potential usefulness of a rice-based, short glucose polymer oral rehydration solution (ORS), Amylyte, in the treatment of acute diarrhea. Amylyte has a similar osmolality but a higher caloric density than the WHO ORS.

METHODS

Different amounts of rice were cooked in 500 ml of water containing salts (1.5 g NaCl, 600 mg KCl, and 150 mg CaCl2) with varying amounts of thermophilic amylase (252,500 modified Wohlgemuth units). Amylase (25 mg) thinned the gluey rice water when 100 g of rice was cooked in 500 ml of water for 10 minutes. The volume of the resultant supernatant (Amylyte) was approximately 250 ml. A two-part, clinical case study was performed. In study 1, 12 children with diarrhea and mild dehydration were studied to determine the safety of Amylyte. In study 2, Amylyte and the WHO ORS were given to 24 and 31 male children with acute diarrhea and moderate to severe dehydration, respectively.

RESULTS

92-96% of the rice amylose and amylopectin were converted to short polymers of glucose (3-9 molecules of glucose). The osmolality of 7,994 packages used to make the Amylyte solution ranged between 277-340 mOsm/kg. The mean electrolyte composition was Na+ = 68 mEq/L, K+ = 20 mEq/L, Cl = 73 mEq/L, the caloric density 425 kcal/L and rice proteins 0.7 g/L. In study 1, 12 children with diarrhea and mild dehydration were rehydrated successfully with Amylyte ORS and the diarrhea ceased within 48 hours. None developed clinical features of carbohydrate intolerance. In study 2, an open-label clinical case study, children with acute diarrhea given Amylyte ORS had significantly less stool output than children given the WHO ORS.

CONCLUSIONS

Amylyte ORS has the advantages of a higher caloric density than the WHO ORS and shares a simple preparation of appropriate osmolality and electrolyte composition. It can safely and effectively rehydrate children with acute diarrhea and dehydration.

High-calorie, rice-derived, short-chain, glucose polymer-based oral rehydration solution in acute watery diarrhea

In this study, we have compared the effects of the World Health Organization oral rehydration solution (WHO ORS) and an ORS containing short polymers of glucose (Amylyte ORS) at a high caloric density (five times) and comparable osmolality, on stool output, duration of diarrhea, weight gain and fluid and electrolyte balance, in randomized, open-labeled, controlled clinical trials in five centers. A total of 198 male children (4 months to 10 years) with acute diarrhea ( <72 h after onset) were assigned by random allocation to either WHO ORS or Amylyte ORS at five centers in Asia. Children were stratified according to grade of dehydration (mild, moderate or severe) and the initial purging rates during the first 6 h (low ( < 2 ml/kg/h), moderate (2-5 ml/kg/h) and high ( > 5 ml/kg/h) purgers). The clinical characteristics of the children in the two treatment groups were comparable. Amylyte ORS reduced stool volumes significantly in children with severe dehydration (285.4 +/- 74.2 versus 75.5 +/- 20.0 ml/kg; p < 0.05) and in children with a high initial purging rate (200.3 +/- 42.8 versus 130.5 +/- 9.1 ml/kg; p < 0.05). This was accompanied by a significant (276.4 +/- 14.6 versus 227.6 +/- 11.8 ml/kg; p < 0.01) reduction in ORS requirements in the Amylyte ORS treated group, the effect being greatest in children with severe dehydration (491.5 +/- 108.5 versus 155.7 +/- 27.3 ml/kg; p < 0.01) or high initial purging rates (394.2 +/- 66.2 versus 316.8 +/- 34.8 ml/kg; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)