Enteral crude red kidney bean (Phaseolus vulgaris) lectin--phytohemagglutinin--induces maturational changes in the enterocyte membrane proteins of suckling rats

Finding the sweet spot: glycosylation mediated regulation of intestinal inflammation

Glycans are essential cellular components that facilitate a range of critical functions important for tissue development and mucosal homeostasis. Furthermore, specific alterations in glycosylation represent important diagnostic hallmarks of cancer that contribute to tumor cell dissociation, invasion, and metastasis. However, much less is known about how glycosylation contributes to the pathobiology of inflammatory mucosal diseases. Here we will review how epithelial and immune cell glycosylation regulates gut homeostasis and how inflammation-driven changes in glycosylation contribute to intestinal pathobiology.

Medicinal Plants, Phytochemicals, and Their Impacts on the Maturation of the Gastrointestinal Tract

The gastrointestinal tract (GIT) is the first point of contact for ingested substances and thus represents a direct interface with the external environment. Apart from food processing, this interface plays a significant role in immunity and contributes to the wellbeing of individuals through the brain-gut-microbiota axis. The transition of life from the in utero environment, to suckling and subsequent weaning has to be matched by phased development and maturation of the GIT; from an amniotic fluid occupancy during gestation, to the milk in the suckling state and ultimately solid food ingestion at weaning. This phased maturation of the GIT can be affected by intrinsic and extrinsic factors, including diet. Despite the increasing dietary inclusion of medicinal plants and phytochemicals for health benefits, a dearth of studies addresses their impact on gut maturation. In this review we focus on some recent findings mainly on the positive impact of medicinal plants and phytochemicals in inducing precocious maturation of the GIT, not only in humans but in pertinent animals. We also discuss Paneth cells as mediators and potential markers of GIT maturation.

Probiotic Lactobacillus plantarum 299v does not counteract unfavorable phytohemagglutinin-induced changes in the rat intestinal microbiota

Application of phytohemagglutinin (PHA) in weaning feed has been suggested to stimulate intestinal epithelium maturation. In this study, PHA strongly affected the fecal bacterial population structure of rats. Escherichia coli overgrowth was not prevented by probiotic mannose-adhering Lactobacillus plantarum 299v. Therefore, use of PHA in weaning feed deserves careful evaluation.

The effects of orally administered crude alcohol and aqueous extracts of African potato (Hypoxis hemerocallidea) corm on the morphometry of viscera of suckling rats

The litter from six Sprague-Dawley rats was used to study the short-term effects of African potato (AP) corm extracts in suckling rats. Ten days after birth, the pups in each litter were assigned to treatment groups and received alcohol (AL) or aqueous (AQ) extracts of AP (50 mg kg(-1) b.w. in 0.9% saline, 10 ml kg(-1) b.w., and a high dose 200 mg kg(-1) b.w. in 0.9% saline, 10 ml kg(-1) b.w.) via a stomach tube, for 5 consecutive days. A fifth group (control) received 0.9% saline (10 ml kg(-1) b.w.). Between gavage, the pups were kept with their dams. The pups were then killed and the viscera removed for gross and microscopic morphometric measurements. The low dose of AQ and AL extracts of AP significantly increased (P<0.01, ANOVA) the mean weight gain. The high dose of AQ significantly increased (P<0.05, ANOVA) the weight of the caeca whilst the low dose of the AL extract reduced pancreas weight compared to the control and low dose AQ groups. All other morphometric parameters of the viscera measured did not differ significantly between the groups. The small intestinal villi and crypts did not reveal any signs of pathology.

Differential Effects of Cooked Beans and Cooked Lentils on Protein Metabolism in Intestine and Muscle in Growing Rats

AIMS

The effect of diets based on cooked beans or lentils on protein metabolism in intestines and muscles was studied in rats.

METHOD

The cooked seeds were used as the unique protein source in balanced diets (containing 229 and 190 g of crude protein per kg dry matter) fed to young growing rats for 20 days. Their effects were compared with those of the control casein diet in pair-fed rats. Protein synthesis rates in small and large intestines and in gastrocnemius and soleus muscles were determined in vivo, in a fed state, by the flooding dose method, using 13C-valine.

RESULTS

In the small and large intestine tissues of the legume fed groups, protein, RNA relative masses (mg.100 g BM(-1)) and protein synthesis rates (FSR and ASR) were higher than in the control rats (p < 0.05). In gastrocnemius and soleus muscles,protein and RNA contents (in mg) and protein synthesis rates were significantly (p < 0.05) lower in the legume-fed groups than in the control rats.

CONCLUSION

The chronic intake of cooked legumes increased protein synthesis rates in intestinal tissues and decreased them in muscles. This effect was greater for beans than for lentils in the large intestine and in gastrocnemius muscle.

Enterally but Not Parenterally Administered Phaseolus vulgaris Lectin Induces Growth and Precocious Maturation of the Gut in Suckling Rats

BACKGROUND

The lectin, phytohemagglutinin (PHA) has been shown to induce growth and functional maturation of the gastrointestinal (GI) tract in suckling rats.

OBJECTIVES

To investigate the effect of the administration route, and whether enteral exposure to PHA was necessary to induce functional maturation.

METHODS

Fourteen-day-old rats were daily administered PHA via orogastric feeding (0.05 mg PHA/g BW) or via subcutaneous injection (0.05 or 0.005 mg PHA/g BW) for 3 days, while the controls received saline orogastrically. At 17 days of age, organ weight, intestinal and pancreatic function, and plasma corticosterone levels were analyzed. Moreover, 14-days old pups receiving a single dose of PHA, enterally or parenterally, were sacrificed after 12 h and examined for organ PHA binding using immunohistochemistry.

RESULTS

Enteral PHA exposure resulted in PHA binding in the epithelial lining of the small intestine, increased gastrointestinal growth, reduced intestinal macromolecular absorption, altered the disaccharidase expression towards an adult-like pattern, and increased the pancreatic protein and trypsin contents. In contrast, parenteral PHA exposure (high dose) resulted in PHA-binding in extra-intestinal organs, increased liver and spleen weight, and decreased thymus weight. Moreover, the intestinal maltase activity increased moderately, and the transfer of BSA to blood plasma was partially reduced. Both PHA treatments led to elevated plasma corticosterone levels.

CONCLUSION

These results demonstrated that enteral exposure to PHA was necessary to induce the precocious maturation of the GI tract and the pancreas, while parenteral administration affects the extra-intestinal organs. Furthermore, the enteral effects were probably not mediated via a corticosteroid dependent pathway.

Induced growth and maturation of the gastrointestinal tract after Phaseolus vulgaris lectin exposure in suckling rats

OBJECTIVES

In mammals, the postnatal development of the gastrointestinal tract is characterized by vast structural and functional changes. Using a suckling rat model, we investigated whether red kidney bean lectin, phytohemagglutinin (PHA), a potent gut mitogen in adult rats, can accelerate the growth and maturation of the gastrointestinal tract.

METHODS

At either 10 or 14 days of age, suckling rats were daily gavage fed with PHA (0.05 mg/g body weight) or saline for 3 days. At 1 or 3 days after this treatment, gastrointestinal organ growth, intestinal morphology, disaccharidase pattern, macromolecular absorption capacity, and pancreatic enzyme contents were studied.

RESULTS

After PHA exposure, increased small intestinal growth and number of crypt cells were observed, whereas the proportion of enterocytes with supranuclear vacuoles in the distal intestine was decreased. The macromolecular absorption of the markers bovine immunoglobulin (Ig)G and bovine serum albumin and plasma levels of maternal IgG decreased, and intestinal disaccharidases switched toward an adult-like pattern. The pancreas weight and pancreatic protein and trypsin contents increased. These changes were partly reversible when the PHA treatment began at 10 days of age, but they persisted when the treatment began at 14 days of age.

CONCLUSIONS

PHA induced enhanced growth and precocious functional maturation of the gastrointestinal tract in suckling rats. The effects persisted if the PHA treatment started at 14 days of age, but not before, suggesting an age dependent mechanism. These findings may lead to a better understanding of gastrointestinal maturation and constitute a basis for the treatment of mammals having an immature gut.

Mucoadhesive microspheres for controlled drug delivery

Mucoadhesion is a topic of current interest in the design of drug delivery systems. Mucoadhesive micro-spheres exhibit a prolonged residence time at the site of application or absorption and facilitate an intimate contact with the underlying absorption surface and thus contribute to improved and/or better therapeutic performance of drugs. In recent years such mucoadhesive microspheres have been developed for oral, buccal, nasal, ocular, rectal and vaginal routes for either systemic or local effects. The objective of this article is review the principles underlying the development and evaluation of mucoadhesive microspheres and the research work carried out on these systems.