Location: Children's Nutrition Research CenterTitle: Improved starch digestion of sucrase deficient shrews treated with oral glucoamylase enzyme supplements
|Nichols, Buford - Children'S Nutrition Research Center (CNRC)|
|Avery, Stephen - Children'S Nutrition Research Center (CNRC)|
|Quezada-calvillo, Roberto - Autonomous University Of San Luis Potosi|
|Kilani, Shadi - Children'S Nutrition Research Center (CNRC)|
|Lin, Amy - Purdue University|
|Burrin, Douglas - Doug|
|Hodges, Benjamin - Children'S Nutrition Research Center (CNRC)|
|Chacko, Shaji - Children'S Nutrition Research Center (CNRC)|
|Opekun, Antone - Children'S Nutrition Research Center (CNRC)|
|Hindawy, Marwa - Purdue University|
|Hamaker, Bruce - Purdue University|
|Oda, Sen - Okayama University|
Submitted to: Journal of Pediatric Gastroenterology and Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2017
Publication Date: 3/6/2017
Citation: Nichols, B.L., Avery, S.E., Quezada-Calvillo, R., Kilani, S.B., Lin, A.H., Burrin, D.G., Hodges, B.E., Chacko, S.K., Opekun, A.R., Hindawy, M.E., Hamaker, B.R., Oda, S.I. 2017. Improved starch digestion of sucrase deficient shrews treated with oral glucoamylase enzyme supplements. Journal of Pediatric Gastroenterology and Nutrition. doi:10.1097/MPG.0000000000001561.
Interpretive Summary: Congenital Sucrase-isomaltase Deficiency (CSID) is a genetic disease usually recognized when infants are weaned from breast milk or formula to baby foods containing table sugar, especially sucrose. The enzyme that digests sucrose, called sucrase, is not present at normal levels in CSID and this usually leads to diarrhea and belly pain in these infants. Sometimes in CSID infants there is also a lower level of enzymes, especially maltase-glucoamylase (MGAM), that digest starch a more complex form of sugar. To treat this condition, CSID infants are often given enzymes made by yeast to digest the sucrose, but they don’t digest the starch when it is fed. The aim of this study was to use a novel animal model of the Asian shrews that mimic the CSID infants and test whether they have a defective capacity to digest starch and whether treatment with a recombinant MGAM could promote normal digestion. The results showed that Asian shrews had deficient sucrose digestion, but partial capacity to digest starch that was increased with supplementation of recombinant MGAM. This study of this animal model of CSID supports the idea that sucrase deficiency reduces starch digestion and that this can be improved by an oral supplement of active enzyme.
Technical Abstract: Although named because of its sucrose hydrolytic activity, this mucosal enzyme plays a leading role in starch digestion because of its maltase and glucoamylase activities. Sucrase deficient mutant shrews, Suncus murinus, were used as a model to investigate starch digestion in patients with Congenital Sucrase-isomaltase Deficiency (CSID). Starch digestion is much more complex than sucrose digestion. Six enzyme activities, two alpha-amylases (Amy) and four mucosal alpha-glucosidases (maltases), including maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si) subunit activities, are needed to digest starch to absorbable free glucose. Amy breaks down insoluble starch to soluble dextrins; mucosal Mgam and Si can either directly digest starch to glucose or convert the post-alpha-amylolytic dextrins to glucose. Starch digestion is reduced due to sucrase deficiency and oral glucoamylase enzyme supplement can correct the starch maldigestion. Measure glucogenesis in suc/suc shrews after feeding of starch and improvement of glucogenesis by oral glucoamylase supplements. Sucrase mutant (suc/suc) and heterozygous (+/suc) shrews were fed with C enriched starch diets. Glucogenesis derived from starch was measured as blood C-glucose enrichment and oral recombinant C-terminal Mgam glucoamylase (M20) was supplemented to improve starch digestion. After feedings, suc/suc and +/suc shrews had different starch digestions as shown by blood glucose enrichment and the suc/suc had lower total glucose concentrations. Oral supplements of glucoamylase increased suc/suc total blood glucose and quantitative starch digestion to glucose. We concluded that: 1. Sucrase deficiency, in this model of CSID, reduces blood glucose response to starch feeding. 2. Supplementing the diet with oral recombinant glucoamylase significantly improved starch digestion in the sucrase deficient shrew.