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Pathophysiology of carbohydrate metabolism

Pathophysiology of carbohydrate metabolism: Physiologic remarks, disturbancies in Carbohydrate Resorbtion, other specific types of DM, chronic complications , | PATHOPHYSIOLOGY OF CARBOHYDRATE METABOLISM Prof. J. Hanacek, MD, PhD Technical co-operative: L.Šurinová A. Physiologic remarks: Carbohydrates are present in food in various forms: 1. simple sugars - monosaccharides 2. complex chemical units - disaccharides - polysaccharides Processing of carbohydrates in GIT Ingested carbohydrates cleaving proces monosaccharides absorbtion in stomach, duodenum and proximal jejunum B. Disturbancies in Carbohydrate Resorbtion 1. Disaccharidase deficiency syndrome saccharase = enzyme which hydrolyses disaccharide saccharose (to fructose and glucose) laktase = enzyme which splits disaccharide lactose (to glucose and galactose) maltase = enzyme which splits disaccharide maltose (to two molecule of glucose) Pathomechanisms Activity of disaccharidase is decreased decreased hydrolysis of disaccharide decreased resorbtion of substrate increased concentration of disaccharide in small intestine lumen increased osmotic activity of the lumen fluid | PATHOPHYSIOLOGY OF CARBOHYDRATE METABOLISM Prof. J. Hanacek, MD, PhD Technical co-operative: L.Šurinová A. Physiologic remarks: Carbohydrates are present in food in various forms: 1. simple sugars - monosaccharides 2. complex chemical units - disaccharides - polysaccharides Processing of carbohydrates in GIT Ingested carbohydrates cleaving proces monosaccharides absorbtion in stomach, duodenum and proximal jejunum B. Disturbancies in Carbohydrate Resorbtion 1. Disaccharidase deficiency syndrome saccharase = enzyme which hydrolyses disaccharide saccharose (to fructose and glucose) laktase = enzyme which splits disaccharide lactose (to glucose and galactose) maltase = enzyme which splits disaccharide maltose (to two molecule of glucose) Pathomechanisms Activity of disaccharidase is decreased decreased hydrolysis of disaccharide decreased resorbtion of substrate increased concentration of disaccharide in small intestine lumen increased osmotic activity of the lumen fluid diarrhea b) Activity of disaccharidase is decreased increased concentration of disaccharide in small intestine lumen increased concentration of disaccharide in large intestine disaccharide fermentation by bacteria increased concentration of lactic acid and fatty acids stimulation of intestine wall abdominal cramps, bloating, diarrhea, acidic stools, explosive diarrhea Lactase deficiency syndrome Causes of lactase deficiency: - genetic defect (primary) - secondary to a wide variety of gastrointestinal diseases that damage the mucosa of the small intestine (secondary) Disaccharide lactose is the principal carbohydrate in milk. - Many persons showing milk intolerance prove to be lactase – deficient - Primary lactase deficiency incidence is as high as 80 % to 90 % among African - Americans, Asians, and Bantus population - Milk intolerance may not become clinically apparent until adolescence Causes of secondary lactase deficiency: - nontropical (celiac disease)and tropical