Importance of milk and diet on the ontogeny and adaptation of the intestine

Transcriptomic profiling of intestinal epithelial cells in response to human, bovine and commercial bovine lactoferrins

Lactoferrin (Lf) is an iron-binding glycoprotein present in high concentration in human milk. It is a pleiotropic protein and involved in diverse bioactivities, such as stimulation of cell proliferation and immunomodulatory activities. Lf is partly resistant to proteolysis in the gastrointestinal tract. Thus, Lf may play important roles in intestinal development. Due to differences in amino acid sequences and isolation methods, Lfs from human and bovine milk as well as commercially available bovine Lf (CbLf) may differ functionally or exert their functions via various mechanisms. To provide a potential basis for further applications of CbLf, we compared effects of Lfs on intestinal transcriptomic profiling using an intestinal epithelial cell model, human intestinal epithelial crypt-like cells (HIEC). All Lfs significantly stimulated proliferation of HIEC and no significant differences were found among these three proteins. Microarray assays were used to investigate transcriptomic profiling of intestinal epithelial cells in response to Lfs. Selected genes were verified by RT-PCR with a high validation rate. Genes significantly regulated by hLf, bLf, and CbLf were 150, 395 and 453, respectively. Fifty-four genes were significantly regulated by both hLf and CbLf, whereas 129 genes were significantly modulated by bLf and CbLf. Although only a limited number of genes were regulated by all Lfs, the three Lfs positively influenced cellular development and immune functions based on pathway analysis using IPA (Ingenuity). Lfs stimulate cellular and intestinal development and immune functions via various signaling pathways, such as Wnt/β-catenin signaling, interferon signaling and IL-8 signaling.

A meta-analysis of probiotic efficacy for gastrointestinal diseases

Background

Meta-analyses on the effects of probiotics on specific gastrointestinal diseases have generally shown positive effects on disease prevention and treatment; however, the relative efficacy of probiotic use for treatment and prevention across different gastrointestinal diseases, with differing etiology and mechanisms of action, has not been addressed.

Methods/Principal Findings

We included randomized controlled trials in humans that used a specified probiotic in the treatment or prevention of Pouchitis, Infectious diarrhea, Irritable Bowel Syndrome, Helicobacter pylori, Clostridium difficile Disease, Antibiotic Associated Diarrhea, Traveler's Diarrhea, or Necrotizing Enterocolitis. Random effects models were used to evaluate efficacy as pooled relative risks across the eight diseases as well as across probiotic species, single vs. multiple species, patient ages, dosages, and length of treatment. Probiotics had a positive significant effect across all eight gastrointestinal diseases with a relative risk of 0.58 (95% (CI) 0.51–0.65). Six of the eight diseases: Pouchitis, Infectious diarrhea, Irritable Bowel Syndrome, Helicobacter pylori, Clostridium difficile Disease, and Antibiotic Associated Diarrhea, showed positive significant effects. Traveler's Diarrhea and Necrotizing Enterocolitis did not show significant effects of probiotcs. Of the 11 species and species mixtures, all showed positive significant effects except for Lactobacillus acidophilus, Lactobacillus plantarum, and Bifidobacterium infantis. Across all diseases and probiotic species, positive significant effects of probiotics were observed for all age groups, single vs. multiple species, and treatment lengths.

Conclusions/Significance

Probiotics are generally beneficial in treatment and prevention of gastrointestinal diseases. Efficacy was not observed for Traveler's Diarrhea or Necrotizing Enterocolitis or for the probiotic species L. acidophilus, L. plantarum, and B. infantis. When choosing to use probiotics in the treatment or prevention of gastrointestinal disease, the type of disease and probiotic species (strain) are the most important factors to take into consideration.

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. This early forced adaptation may persist in later life, such as the unwanted increased intestinal absorption of sugars, fatty acids and cholesterol. Thus, the ontogeny, early growth and development of the intestine is important for the adult gastroenterologist to appreciate, because of the potential for these early life events to affect the responsiveness of the intestine to physiological or pathological challenges in later life.

Host factors in amniotic fluid and breast milk that contribute to gut maturation

The gut represents a complex organ system with regional differences, which reflect selective digestive and absorptive functions that change constantly in response to bodily requirements and the outside milieu. As a barrier to the external environment, gut epithelium must be renewed rapidly and repeatedly. Growth and renewal of gut epithelial cells is dependent on controlled cell stimulation and proliferation by a number of signaling processes and agents, including gut peptides-both endogenous and exogenous sources. This cascade of events begins during fetal development; with the ingestion of amniotic fluid, this process is enhanced and continued during infancy and early childhood through the ingestion of human milk. Events influenced by amniotic fluid during fetal development and those influenced by human milk that unfold after birth and early childhood to render the gut mature are presented.

Dietary unsaturated long-chain Fatty acids modify D-glucose absorption in weaning rats

OBJECTIVE

The authors evaluated the effects of dietary long-chain polyunsaturated fatty acids on D-glucose absorption in weaning rats.

METHODS

Pups were born from control mothers fed a diet containing (per kg of total fatty acids) 280 g of saturated fatty acids, 496 g of monounsaturated fatty acids and 222 g of polyunsaturated fatty acids or from mothers fed a diet containing a high proportion of saturated fatty acids (920 g/kg) and a low proportion of unsaturated fatty acids (low-unsaturated fatty acid, 80 g/kg), initiated 2 weeks before mating and continued throughout pregnancy. When pups from low-unsaturated fatty acid mothers were 15 days old, they were subdivided into two groups: one control (low-unsaturated fatty acid-C) and one fed a long-chain polyunsaturated fatty acid supplement rich in arachidonic acid and docosahexaenoic acid (low-unsaturated fatty acid-S) until weaning. At day 21, the kinetics of D-glucose absorption was studied in brush-border membrane vesicles from the jejunoileal segment.

RESULTS

The maximal transport rate (V(max)) of glucose in the low-unsaturated fatty acid-C and low-unsaturated fatty acid-S groups was higher than in control rats: 160 and 130 versus 98 pmol/(mg protein.s), respectively (P < 0.05). Rats fed the low-unsaturated fatty acid diet had a lower diffusion constant (K(d)) than control rats did: 21.6 and 29.2 nL/(mg protein.s), respectively (P < 0.05). However, rats receiving the long-chain polyunsaturated fatty acid supplement and control rats had similar Kd values.

CONCLUSION

These results indicate that dietary long-chain polyunsaturated fatty acid supplementation can restore, in part, the kinetic characteristics of intestinal D-glucose absorption in pups from mothers maintained on a low-unsaturated fatty acid diet.

A review of the effects of breastfeeding on respiratory infections, atopy, and childhood asthma

The etiology of childhood asthma is not fully understood. Early exposure to certain respiratory infections may be protective for atopy and/or asthma whereas some infections have been suggested to exert the opposite effects. Wheezing lower respiratory illness (LRI) in the first year of life and atopy are independently associated with increased risk for current asthma in childhood and their effects are mediated via different causal pathways. These risk factors are multiplicative when they operate concommitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms. Furthermore, exclusive breastfeeding may protect against asthma and may reduce the incidence of lower respiratory illness, especially respiratory syncytial virus (RSV). We have previously demonstrated a protective effect of exclusive breastfeeding on asthmatic traits in children. The aim of this review was to clarify this protective association from intermediate associations with respiratory infections, atopy, or through other facets of breastfeeding. The bioactivity of breast milk and subsequent pathways that may act upon the development of asthma in children are explored.

Probiotics: effects on immunity

The gastrointestinal tract functions as a barrier against antigens from microorganisms and food. The generation of immunophysiologic regulation in the gut depends on the establishment of indigenous microflora. This has led to the introduction of novel therapeutic interventions based on the consumption of cultures of beneficial live microorganisms that act as probiotics. Among the possible mechanisms of probiotic therapy is promotion of a nonimmunologic gut defense barrier, which includes the normalization of increased intestinal permeability and altered gut microecology. Another possible mechanism of probiotic therapy is improvement of the intestine's immunologic barrier, particularly through intestinal immunoglobulin A responses and alleviation of intestinal inflammatory responses, which produce a gut-stabilizing effect. Many probiotic effects are mediated through immune regulation, particularly through balance control of proinflammatory and anti-inflammatory cytokines. These data show that probiotics can be used as innovative tools to alleviate intestinal inflammation, normalize gut mucosal dysfunction, and down-regulate hypersensitivity reactions. More recent data show that differences exist in the immunomodulatory effects of candidate probiotic bacteria. Moreover, distinct regulatory effects have been detected in healthy subjects and in patients with inflammatory diseases. These results suggest that specific immunomodulatory properties of probiotic bacteria should be characterized when developing clinical applications for extended target populations.

Effect of age and weaning on gastric mucosal injury in developing rats

We evaluated ethanol- and HCl-induced mucosal damages in developing rats. The degree of damage induced by ethanol and HCl was greatest in 1-week-old rats and decreased significantly with age until 4 weeks; thereafter it increased again. To evaluate the effect of weaning on the maturational changes in mucosal defense, we compared ethanol-induced mucosal damage among three groups of newborn rats: (1) receiving milk only; (2) receiving only rat chow from 14 days of age, and (3) having free access to milk and chow. There were no significant differences at 18 and 21 days of age. The mucus thickness increased with age until 8 weeks and was not affected by weaning. In conclusion, developmental changes occur in gastric mucosal protection in rats. Weaning does not have a significant effect on these changes.