Specific protein supplementation using soya, casein or whey differentially affects regional gut growth and luminal growth factor bioactivity in rats; implications for the treatment of gut injury and stimulating repair

Modulation of regional growth within specific segments of the bowel may have clinical value for several gastrointestinal conditions. We therefore examined the effects of different dietary protein sources on regional gut growth and luminal growth factor bioactivity as potential therapies. Rats were fed for 14 days on isonitrogenous and isocaloric diets comprising elemental diet (ED) alone (which is known to cause gut atrophy), ED supplemented with casein or whey or a soya protein-rich feed. Effects on regional gut growth and intraluminal growth factor activity were then determined. Despite calorie intake being similar in all groups, soya rich feed caused 20% extra total body weight gain. Stomach weight was highest on soya and casein diets. Soya enhanced diet caused greatest increase in small intestinal weight and preserved luminal growth factor activity at levels sufficient to increase proliferation in vitro. Regional small intestinal proliferation was highest in proximal segment in ED fed animals whereas distal small intestine proliferation was greater in soya fed animals. Colonic weight and proliferation throughout the colon was higher in animals receiving soya or whey supplemented feeds. We conclude that specific protein supplementation with either soya, casein or whey may be beneficial to rest or increase growth in different regions of the bowel through mechanisms that include differentially affecting luminal growth factor bioactivity. These results have implications for targeting specific regions of the bowel for conditions such as Crohn's disease and chemotherapy.

[The role of chemokines in nasal polyps]

Nasal polyposis is an inflammatory condition of the nose and the sinuses characterised by a marked infiltration of eosinophils in addition to lymphocytes, mast cells and macrophages. The selective recruitment of eosinophils to inflammatory sites is mediated by CC chemokines such as Eotaxin and Eotaxin-2. In the present study histology, immunohistochemistry and ELISA were performed. The levels of Eotaxin and Eotaxin-2 and for comparison other chemokines RANTES and IL-8 were measured in nasal polyp tissue and in control nasal tissue. On histological examination 6 polyps showed an oedematous structure, one was glandular and one had a fibromatous pattern, while all showed a marked eosinophil infiltration. Immunohistochemistry of the polyps showed that epithelial cells were strongly positive for Eotaxin and IL-8, whereas endothelial cells stained positive for Eotaxin-2. Significantly higher amounts of Eotaxin, Eotaxin-2 and IL-8 were detected in polyp tissue when compared with control middle turbinates. The increased levels of eosinophil-stimulating chemokines, such as Eotaxin and Eotaxin-2 in nasal polyps suggest that they may be important regulators of eosinophil recruitment in this inflammatory disease.

Vicia faba agglutinin, the lectin present in broad beans, stimulates differentiation of undifferentiated colon cancer cells

BACKGROUND

Dietary lectins can alter the proliferation of colonic cells. Differentiation is regulated by adhesion molecules which, being glycosylated, are targets for lectin binding.

AIMS

To examine the effects of dietary lectins on differentiation, adhesion, and proliferation of colorectal cancer cells.

METHODS

Differentiation was assessed in three dimensional gels, adhesion by aggregation assay, and proliferation by 3H thymidine incorporation. The role of the epithelial cell adhesion molecule (epCAM) was studied using a specific monoclonal antibody in blocking studies and Western blots. The human colon cancer cell lines LS174T, SW1222, and HT29 were studied.

RESULTS

The cell line LS174T differentiated in the presence of Vicia faba agglutinin (VFA) into gland like structures. This was inhibited by anti-epCAM monoclonal antibody. Expression of epCAM itself was unaffected. VFA as well as wheat germ agglutinin (WGA) and the edible mushroom lectin (Agaricus bisporus lectin, ABL) significantly aggregated LS174T cells but peanut agglutinin (PNA) and soybean agglutinin (SBA) did not. All lectins aggregated SW1222 and HT29 cells. Aggregation was blocked by the corresponding sugars. Aggregation of cells by VFA was also inhibited by anti-epCAM. VFA, ABL, and WGL inhibited proliferation of all the cell lines; PNA stimulated proliferation of HT29 and SW1222 cells. In competition studies all sugars blocked aggregation and proliferation of all cell lines, except that the addition of mannose alone inhibited proliferation.

CONCLUSION

VFA stimulated an undifferentiated colon cancer cell line to differentiate into gland like structures. The adhesion molecule epCAM is involved in this. Dietary or therapeutic VFA may slow progression of colon cancer.

Nonparenchymal cells from regenerating rat liver generate interleukin-1alpha and -1beta: a mechanism of negative regulation of hepatocyte proliferation

Following experimental partial hepatectomy of 70% in the rat, there is a semisynchronized surge of hepatocyte proliferation that ceases after 48 to 72 hours. Little is known about the determinants governing the termination of the proliferative phase, although transforming growth factor (TGF) beta has been implicated as an important inhibitor of hepatocyte replication in this model. We previously reported an additional non-TGF-beta inhibitor in medium conditioned by nonparenchymal cells isolated from regenerating liver (CM-NPC-Reg) between 24 and 48 hours after partial hepatectomy, but it was not found in medium conditioned by nonparenchymal cells from unoperated control liver. CM-NPC-Reg suppressed replicative DNA synthesis of primary rat hepatocytes in response to hepatocyte growth factor (HGF), epidermal growth factor (EGF), or TGF-alpha as assessed by 3H-thymidine incorporation. We now present evidence that interleukin (IL)-1 is the major inhibitor of hepatocyte DNA synthesis present in CM-NPC-Reg. IL-1 receptor antagonist abrogated the inhibition, as did antibodies to rat IL-1alpha and -beta; a combination of both antibodies was required, implicating both IL-1alpha and IL-1beta as active constituents in CM-NPC-Reg. To investigate in vivo changes in IL-1 expression, we assessed expression of IL-1alpha messenger RNA (mRNA) in whole rat liver following partial hepatectomy; mRNA was down-regulated at 10 hours in the pre-replicative phase of liver regeneration and up-regulated at 24 hours and 48 hours when proliferation is waning. Rat hepatocytes isolated from liver 24 hours after partial hepatectomy showed increased sensitivity to the inhibitory action of IL-1. Exogenous IL-1beta, administered parenterally to a group of rats at 0 and 12 hours after partial hepatectomy significantly reduced the incorporation of the thymidine analogue, bromodeoxyuridine (BrdU), into hepatocytes at 18 hours. These data indicate that nonparenchymal cells isolated from regenerating rat liver elaborate IL-1, and support the hypothesis that IL-1 plays a role suppressing hepatocyte proliferation and terminating the surge of DNA synthesis induced after partial hepatectomy.

Histidinemia in mice: a metabolic defect treated using a novel approach to hepatocellular transplantation

Histidinemia in mice and in humans is an autosomal recessive disorder of histidine metabolism that leads to high-histidine levels in both plasma and urine and is caused by a lack of hepatic histidine-alpha-deaminase (histidase). We have used a novel approach to hepatocellular transplantation to effect a complete phenotypic cure of histidinemia in a mouse model. Mice lacking histidase were treated with isolated liver cells (approximately 18 x 10(6) hepatocytes and 9 x 10(6) nonparenchymal cells) from histidase-competent donors transplanted into the peritoneum (active transplant group). Recipient mice showed a dramatic decrease, by more than 75%, in urinary histidine levels from day one throughout the course of the experiment, resulting in levels within the normal range for wild-type mice. In comparison, there was no change in urinary histidine levels in the control group of histidase-deficient mice treated with isolated liver cells from mice lacking histidase (statistical comparison between the two groups, P < .003, two-way ANOVA). Histologically, ectopic liver tissue was seen in the peritoneum in association with abdominal wall, pancreas, and peritoneal connective tissue; immunohistochemical evidence showed expression of histidase in the ectopic liver tissue in the active transplant group. This report is the first to show complete correction of a defective biochemical phenotype achieved by hepatocellular transplantation.

Hepatocyte growth factor (HGF/SF) is expressed in human epithelial cells during embryonic development; studies by in situ hybridisation and northern blot analysis

This study reports the tissue distribution of Hepatocyte Growth Factor-Scatter Factor (HGF/SF) in human fetal tissue using Northern analysis and in situ hybridisation techniques. In tissue from fetuses of 9-17 wk gestational age, the 6 kb mRNA transcript for HGF/SF was demonstrated in many tissues but prominently in liver, intestine, gall bladder and spleen. In situ hybridisation demonstrated that HGF/SF expression was not confined to mesenchymal tissues, as suggested by previous studies but was expressed in epithelial tissues, particularly in small intestine, keratinising epithelium of tongue, skin and oesophagus. In the small intestine epithelial expression was strikingly regional, being confined to the crypt region, the site of enterocyte proliferation. Northern analysis of tissues for c-met mRNA, representing expression of the HGF/SF receptor, demonstrated receptor expression in all tissues studied except the thyroid gland.