Mathematical correlation between villus height and the nutritional state in Sprague-Dawley rats

Apple polyphenols improve intestinal barrier function by enhancing antioxidant capacity and suppressing inflammation in weaning piglets

This study aimed to examine the effects of apple polyphenols (APPs) on antioxidant capacity, immune and inflammatory response, and barrier function in weaning piglets. Results showed that APPs improved jejunal barrier function by increasing the villus height, villus height/crypt depth, the mRNA levels of occludin, mucin-1, and mucin-4 and up-regulating the protein expression of occluding (P < 0.05). As for antioxidant capacity, APPs increased the activities of total superoxide dismutase and glutathione peroxidase and total antioxidant capacity level in jejunum (P < 0.05). Besides, APPs up-regulated the protein expressions of NAD(P)H quinone dehydrogenase 1 (NQO1), heme oxygenase-1 (HO-1), and nuclear-related factor 2 (NRF2) and down-regulated the protein expression of kelch-like ECH-associated protein 1 (Keap1). As regard to immune and inflammatory response, APPs increased the immunoglobulin A content in serum and decreased the mRNA levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB), and IL-8 in jejunum (P < 0.05). Overall, dietary APPs supplementation improves the jejunal barrier function by enhancing antioxidant capacity and suppressing the mRNA expression related to inflammation, which may be related to the NRF2 signal and TLR4/NF-κB signal.

Three-dimensional mechanisms of macro-to-micro-scale transport and absorption enhancement by gut villi motions

We evaluate the potential for physiological control of intestinal absorption by the generation of "micromixing layers" (MMLs) induced by coordinated motions of mucosal villi coupled with lumen-scale "macro" eddying motions generated by gut motility. To this end, we apply a three-dimensional (3D) multigrid lattice-Boltzmann model of a lid-driven macroscale cavity flow with microscale fingerlike protuberances at the lower surface. Integrated with a previous 2D study of leaflike villi, we generalize to 3D the 2D mechanisms found there to enhance nutrient absorption by controlled villi motility. In three dimensions, increased lateral spacing within villi within groups that move axially with the macroeddy reduces MML strength and absorptive enhancement relative to two dimensions. However, lateral villi motions create helical 3D particle trajectories that enhance absorption rate to the level of axially moving 2D leaflike villi. The 3D enhancements are associated with interesting fundamental adjustments to 2D micro-macro-motility coordination mechanisms and imply a refined potential for physiological or pharmaceutical control of intestinal absorption.

Jejunal morphology and blood metabolites in tail biting, victim and control pigs

Tail biting has several identified feeding-related risk factors. Tail biters are often said to be lighter and thinner than other pigs in the pen, possibly because of nutrition-related problems such as reduced feed intake or inability to use nutrients efficiently. This can lead to an increase in foraging behavior and tail biting. In this study, a total of 55 pigs of different ages were selected according to their tail-biting behavior (bouts/hour) and pen-feeding system to form eight experimental groups: tail-biting pigs (TB), victim pigs (V) and control pigs from a tail-biting pen (Ctb) and control pen (Cno) having either free access to feed with limited feeding space or meal feeding from a long trough. After euthanasia, a segment of jejunal cell wall was cut from 50 cm (S50) and 100 cm (S100) posterior to the bile duct. Villus height, crypt depth and villus : crypt ratio (V : C) were measured morphometrically. Blood serum concentration of minerals and plasma concentration of amino acids (AA) was determined. Villus height was greater in Cno than Ctb pigs in the proximal and mid-jejunum (P < 0.05), indicative of better ability to absorb nutrients, and increased with age in the proximal jejunum (P < 0.001). Serum mineral concentration of inorganic phosphate (Pi) and calcium (Ca) was lower in Ctb compared with Cno pigs, and that of Pi in V compared with all the other pigs. Many non-essential AA were lower in pigs from tail-biting pens, and particularly in victim pigs. Free access feeding with shared feeding space was associated with lower levels of essential AA in blood than meal feeding with simultaneous feeding space. Our data suggest that being a pig in a tail-biting pen is associated with decreased jejunal villus height and blood AA levels, possibly because of depressed absorption capacity, feeding behavior or environmental stress associated with tail biting. Victim pigs had lower concentrations of AA and Pi in plasma, possibly as a consequence of being bitten.

Enteropathy in Zambians with HIV related diarrhoea: regression modelling of potential determinants of mucosal damage

BACKGROUND

AIDS is characterised by small intestinal mucosal damage, but its aetiopathogenesis is poorly understood. Enteric infections in Africa differ from those in northern countries, where protozoan infections have been associated with severe enteropathy in AIDS patients.

AIMS

To characterise enteropathy in Zambian AIDS patients compared with local controls, and to assess relative contributions of enteric infection, nutritional impairment, and immune dysfunction.

METHODS

Computer aided mucosal morphometry of small intestinal biopsy specimens from 56 HIV infected Zambians with persistent diarrhoea and 26 diarrhoea free controls, followed by regression modelling.

RESULTS

Patients with HIV related diarrhoea had reduced villous height and increased crypt depth compared with controls. There was no difference between HIV positive and negative controls. In regression models applied to AIDS mucosal measurements, villous height and crypt depth were related to nutritional parameters and to serum soluble tumour necrosis factor receptor p55 concentration. Crypt depth was also related to lamina propria plasma cell count. Intestinal infection was found in 79%, which consisted predominantly of microsporidia in 34%, Isospora belli in 24%, and Cryptosporidium parvum in 21%, but detection of these enteropathogens was not related to severity of enteropathy.

CONCLUSIONS

Nutritional and immune disturbances were associated with enteropathy, accounting for over one third of the variation in mucosal morphometric parameters.

Morphological characteristics, epithelial cell proliferation, and crypt fission in cecum and colon of growing pigs

Morphological characteristics and cellular proliferation were investigated in the hindgut tissue of 25 pigs ranging from 5 to 261 days of age; the three youngest pigs were unweaned. Tissue samples were taken from the cecum and from the proximal, middle, and distal part of the colon. In the young pigs a high incidence of branched crypts was observed. During the first three to four months there was an increase in crypt height and proliferative activity, as determined by the mitotic count, as well as an increase in the mucin secretion, especially the sulfomucins. Distinct regional differences were observed between the four intestinal sites. In general, the crypts were deeper and more closely spaced and the turnover time was higher in the distal part of the colon as compared to the cecum and the proximal colon. Furthermore, a greater proportion of the mucins in the middle and distal part of the colon are acidic or sulfated as compared to the cecum, where the mucins are more of the neutral type. These regional and age-related differences in morphological characteristics of the hindgut in pigs may have significance for the etiology of intestinal infections.