Ontogeny, growth and development of the small intestine: Understanding pediatric gastroenterology.

Throughout our lifetime, the intestine changes. Some alterations in its form and function may be genetically determined, and some are the result of adaptation to diet, temperature, or stress. The critical period programming of the intestine can be modified, such as from subtle differences in the types and ratios of n3:m6 fatty acids in the diet of the pregnant mother, or in the diet of the weanlings.

Beta-glucan extracts inhibit the in vitro intestinal uptake of long-chain fatty acids and cholesterol and down-regulate genes involved in lipogenesis and lipid transport in rats.

Background: Dietary fiber reduces the intestinal absorption of nutrients and the blood concentrations of cholesterol and triglycerides.

Aim: We wished to test the hypothesis that high-viscosity (HV) and low-viscosity preparations of barley and oat beta-glucan modify the expression of selected genes of lipid-binding proteins in the intestinal mucosa and reduce the intestinal in vitro uptake of lipids.

Methods: Five different beta-glucan extracts were separately added to test solutions at concentrations of 0.

Morphological, kinetic, membrane biochemical and genetic aspects of intestinal enteroplasticity.

The process of intestinal adaptation ("enteroplasticity") is complex and multifaceted. Although a number of trophic nutrients and non-nutritive factors have been identified in animal studies, successful, reproducible clinical trials in humans are awaited. Understanding mechanisms underlying this adaptive process may direct research toward strategies that maximize intestinal function and impart a true clinical benefit to patients with short bowel syndrome, or to persons in whom nutrient absorption needs to be maximized.

Intestinal hormones and growth factors: effects on the small intestine.

There are various hormones and growth factors which may modify the intestinal absorption of nutrients, and which might thereby be useful in a therapeutic setting, such as in persons with short bowel syndrome. In part I, we focus first on insulin-like growth factors, epidermal and transferring growth factors, thyroid hormones and glucocorticosteroids. Part II will detail the effects of glucagon-like peptide (GLP)-2 on intestinal absorption and adaptation, and the potential for an additive effect of GLP2 plus steroids.

Dexamethasone and GLP-2 given to lactating rat dams influence glucose uptake in suckling and postweanling offspring.

Background: Glucagon-like peptide-2 (GLP-2) enhances intestinal absorption in adult animals. Glucocorticosteroids accelerate the ontogeny of the intestine and increase sugar uptake in adult animals. Modifying the maternal diet during lactation alters nutrient uptake in the offspring.

Maternal dexamethasone and GLP-2 have early effects on intestinal sugar transport in their suckling rat offspring.

Both glucagon-like peptide 2 (GLP-2) and glucocorticosteroids enhance intestinal uptake in mature animals. Maternal stimuli may cause intestinal adaptation in the offspring. We hypothesized that administering GLP-2, dexamethasone (DEX) or a combination of GLP-2+DEX to rat dams during pregnancy and lactation would enhance intestinal sugar uptake in their offspring.

Loss of intestinal fatty acid binding protein increases the susceptibility of male mice to high fat diet-induced fatty liver.

Mice lacking I-FABP (encoded by the Fabp2 gene) exhibit a gender dimorphic response to a high fat/cholesterol diet challenge characterized by hepatomegaly in male I-FABP-deficient mice. In this study, we determined if this gender-specific modification of liver mass in mice lacking I-FABP is attributable to the high fat content of the diet alone and whether hepatic Fabp1 gene (encodes L-FABP) expression contributes to this difference. Wild-type and Fabp2-/- mice of both genders were fed a diet enriched with either polyunsaturated or saturated fatty acids (PUFA or SFA, respectively) in the absence of cholesterol.

Dietary gangliosides enhance in vitro glucose uptake in weanling rats.

Background: The intestine adapts to environmental stimuli, such as modifications in dietary lipids. Dietary lipids modify brush border membrane (BBM) permeability and nutrient transporter activities. Gangliosides (GANG) are glycolipids present in human milk, but they are present only in low amounts in infant formula.

Dexamethasone and GLP-2 administered to rat dams during pregnancy and lactation have late effects on intestinal sugar transport in their postweaning offspring.

Intestinal function in young animals is influenced by maternal factors, such as alterations in the maternal diet. Glucagon-like peptide 2 (GLP-2) enhances intestinal growth and absorption in mature animals. Glucocorticosteroids induce intestinal maturation in neonates and increase sugar uptake in adult animals.

Nutritional modulation of the inflammatory response in inflammatory bowel disease--from the molecular to the integrative to the clinical.

Nutrient deficiencies are common in patients with inflammatory bowel disease (IBD). Both total parenteral and enteral nutrition provide important supportive therapy for IBD patients, but in adults these are not useful for primary therapy. Dietary intervention with omega-3 polyunsaturated fatty acids contained in fish oil may be useful for the care of IBD patients, and recent studies have stressed the role of PPAR on NFkappaB activity on the potential beneficial effect of dietary lipids on intestinal function.

Aging and the intestine.

Over the lifetime of the animal, there are many changes in the function of the body's organ systems. In the gastrointestinal tract there is a general modest decline in the function of the esophagus, stomach, colon, pancreas and liver. In the small intestine, there may be subtle alterations in the intestinal morphology, as well as a decline in the uptake of fatty acids and sugars.

Intestinal mucosal adaptation.

Intestinal failure is a condition characterized by malnutrition and/or dehydration as a result of the inadequate digestion and absorption of nutrients. The most common cause of intestinal failure is short bowel syndrome, which occurs when the functional gut mass is reduced below the level necessary for adequate nutrient and water absorption. This condition may be congenital, or may be acquired as a result of a massive resection of the small bowel.

Intestinal sugar transport.

Carbohydrates are an important component of the diet. The carbohydrates that we ingest range from simple monosaccharides (glucose, fructose and galactose) to disaccharides (lactose, sucrose) to complex polysaccharides. Most carbohydrates are digested by salivary and pancreatic amylases, and are further broken down into monosaccharides by enzymes in the brush border membrane (BBM) of enterocytes.

Lipid malabsorption persists after weaning in rats whose dams were given GLP-2 and dexamethasone.

Glucagon-like peptide-2 (GLP-2) enhances intestinal growth and absorption in mature animals, and glucocorticosteroids (GC) increase the sugar and lipid uptake in adult animals. However, the role of GC and GLP-2 in the ontogeny of lipid absorption is unknown. We hypothesized that GLP-2 and the GC dexamethasone (DEX), when administrated to rat dams during pregnancy and lactation, would enhance lipid uptake in the offspring.

Dietary gangliosides enhance in vitro lipid uptake in weanling rats.

Background: The intestine adapts morphologically or functionally in response to environmental stimuli. Dietary lipids modify brush border membrane (BBM) permeability and nutrient transporter activities. Gangliosides (GANG) are glycolipids in human milk that are present only in low amounts in infant formula.

A combination of dexamethasone and glucagon-like peptide-2 increase intestinal morphology and glucose uptake in suckling rats.

Objectives: Glucagon-like peptide (GLP)-2 enhances nutrient uptake in adult animals. Glucocorticosteroids accelerate intestinal ontogeny and increase nutrient uptake in adult animals. We hypothesized that administering GLP-2 and dexamethasone (DEX) to suckling rats will enhance sugar uptake and that this effect persists into the postweaning period.

Treatment of suckling rats with GLP-2 plus dexamethasone increases the ileal uptake of fatty acids in later life.

Glucocorticosteroids such as dexamethasone (Dex) increase sugar and lipid uptake in adult animals and accelerate the development of the immature intestine. The effect of Dex on the ontogeny of lipid absorption is unknown. In adult rats, glucagon-like peptide-2 (GLP-2) has a trophic effect on the intestine and enhances nutrient absorption.

The age-related decline in intestinal lipid uptake is associated with a reduced abundance of fatty acid-binding protein.

Aging is associated with changes in the absorptive capacity of the small intestine. We tested the hypotheses that (i) aging is associated with a decline in lipid absorption, and that (ii) this decreased lipid absorption is due to a decline in the abundance of mRNA and/or the enterocyte cytosolic intestinal FA-binding protein (I-FABP), the liver FA-binding protein (L-FABP), and the ileal lipid-binding protein (ILBP). In vitro uptake studies were performed on Fischer 344 rats at ages 1, 9, and 24 mon.

Age-associated changes in intestinal fructose uptake are not explained by alterations in the abundance of GLUT5 or GLUT2.

A reduction in nutrient absorption may contribute to malnourishment in the elderly. The objectives of this study were to determine the effects of aging on the absorption of fructose in rats, as well as the mechanisms of these adaptive changes. Male Fischer 344 rats aged 1, 9, and 24 months were fed standard Purina chow for 2 weeks (PMI #5001, PMI Nutritionals, Brentwood, MO).

Dexamethasone plus glucagon-like peptide 2 given to lactating rat dams has a late effect on intestinal lipid uptake in the weanling offspring.

Background: Glucagon-like peptide 2 (GLP-2) has a trophic effect on the intestine and enhances intestinal absorption in adult animals, but its effect in young rats is unknown. Glucocorticosteroids accelerate the ontogeny of the intestine, and in adult animals they increase the uptake of sugars and lipids. We hypothesized that GLP-2 and dexamethasone (DEX), when administrated to lactating rat dams, will enhance lipid uptake in the suckling and weanling offspring.

An isocaloric PUFA diet enhances lipid uptake and weight gain in aging rats.

Aging is associated with a change in the morphology and absorptive capacity of the small intestine. In young rats, feeding a semisynthetic diet containing saturated FA (SFA) increases nutrient uptake, as compared with an isocaloric diet containing polyunsaturated FA (PUFA). We tested the hypotheses that (i) aging is associated with a decline in lipid absorption in the Fischer 344 rat; (ii) this decline can be corrected by manipulating the fat composition of the diet; and (iii) the age- and diet-associated variations in lipid uptake are associated with changes in the ileal lipid-binding protein (ILBP) or the intestinal or liver FA-binding proteins (I- or L-FABP, respectively) in the cytosol of the enterocyte.

Acid inhibitory potency of twice a day omeprazole is not affected by eradication of Helicobacter pylori in healthy volunteers.

Background And Aims: The acid inhibitory effect of proton pump inhibitors is reported to be greater in the presence than in the absence of an H. pylori infection. This study was undertaken to test the hypothesis that the acid inhibitory effect of omeprazole given twice a day is greater in H.