Iodine deficiency a persisting problem: assessment of iodine nutrition and evaluation of thyroid nodular pathology in Portugal

BACKGROUND

The goal of eliminating iodine deficiency (ID) by the year 2000 has still not been achieved in several countries. More than 2 billion people worldwide (over 260 million school age children) remain ID. In Europe, there are still countries, such as Portugal, without national general population data on iodine nutrition (IN). This study aims at evaluating combined complementary data of the IN of the general population through urinary iodine concentration (UIC) and the thyroid histology profile from the inland region of Beira Interior (BI), in Portugal.

METHODS

UIC from a population sample of 214 volunteers (131 females and 83 males), with ages ranging from 8 to 97 years (mean 51.5 years ± SD 20.74 years), from BI was determined; the thyroid histology pattern in BI (6-year period) was evaluated; and the iodine content of the largest surface water reservoir of BI, never previously reported, was measured.

RESULTS

Median UIC of 62.6 μg/L was measured. Over 92 % of the population had UIC less than 100 μg/L. From 279 histology reports evaluated, the incidence of the different types of thyroid nodular pathology in BI was established. There were 60 histologic diagnoses of malignancy. The observed ratio of papillary to follicular carcinoma relatively close to 1 and the fairly high percentage of anaplastic carcinomas are characteristic of ID areas.

CONCLUSIONS

The findings of this first general population study on IN from the inland region of BI, Portugal, document significant ID. This problem, with its serious public health implications, could be corrected by having affordable iodised salt widely and generally available and by promoting a proactive population attitude generated by ample public information and educational programs as to the negative consequences of ID.

Total fecal diversion by the temporary skin-level loop transverse colostomy

The temporary skin-level loop transverse colostomy has been described. Proof of its ability to divert the fecal stream totally is illustrated by complete diversion in 25 patients ingesting a postcolostomy barium meal. There was no postoperative complication.

Anorectal Crohn's disease

Anorectal disease affects many patients with Crohn's disease. Clinical manifestations vary from asymptomatic skin tags to severe, debilitating perineal destruction and sepsis. Surgical management needs to be conservative and must focus on draining septic sites, preserving sphincter function, and palliating symptoms. Medical management has had some success in improving symptoms, but as yet, it has not been able to ameliorate most perianal complaints quickly and enduringly. Many new and exciting treatment modalities are being investigated with the hope that more effective approaches to these complex and difficult problems can be realized.

Nutrition

The use of nutrition for the medical patient, in the inpatient setting and at home, will likely continue to increase in the future. Each patient should be evaluated in an individualized but systematic fashion. Each patient in whom malnourishment is suspected should undergo a thorough assessment for the presence and degree of malnutrition with an accurate calculation of nutritional requirements. It is important to choose the correct method of delivery of nutrition, to monitor and recognize any complications or problems that may arise, and to tailor the nutritional therapy to the unique diseases that are encountered in medicine. Although increasingly new advances and changes are occurring in the field of nutrition, nutritional support and therapy are best delivered and supplied to the patient with a network of health care workers, including the physician, the nurse, the dietitian, the social worker, and pharmacist.

Proposed association between ileoanal j-pouch perforation and rapid consumption of a high-calorie, high-fiber meal: report of two cases

PURPOSE

We report two cases of ileoanal J-pouch rupture after rapid consumption of high-fiber, high-calorie meals.

METHOD

We review the food intake, presentation, laboratory and radiographic data, and course of two patients who developed ileoanal J-pouch perforation after rapid consumption of meals rich in fiber or calories or both. The potential association between food consumption and rupture is explored.

RESULTS

The authors propose that the rapid ingestion of a high-fiber, high-calorie meal may lead to an acute intraluminal pressure elevation or a closed-loop obstruction. These effects may be the basis for an association between food ingestion patterns and perforation at the distal transection site in an ileoanal J-pouch.

CONCLUSION

The authors hypothesize that the rapid ingestion of a high-fiber, high-calorie meal may be associated with J-pouch perforation. Further investigative efforts are needed to confirm this association and to evaluate whether a causal relationship is present. If causality is established, physicians may develop a higher index of suspicion for pouch rupture in patients who present with abdominal disturbances after the rapid ingestion of a high-fiber, high-calorie meal.

Practical nutritional management in the trauma intensive care unit

Critically injured patients offer an exceptional challenge to intensivists. Pre-existing disease states complicate horrendous disruptions in normal anatomy and physiology. The hypermetabolic, catabolic response brought on by trauma, shock, or sepsis serves to reprioritize the normal nutritional homeostasis of the body. Appropriate nutritional support not only minimizes the wasting effects of hypermetabolism but potentially offers additional benefits. Studies of feeding routes, substrates, and timing suggest that adequate support may decrease infectious complications and modulate the metabolic response. Injured patients are a heterogenous group, making the definition of adequate support and interpretation of experimental findings difficult. Ultimately, most severely injured patients need directed nutritional support because of their inability to ingest nourishment by conventional means. This article emphasizes a practical approach to these patients.

Nutrition in inflammatory bowel disease

Clinical and basic research continues to expand our understanding of the complex pathogenesis of inflammatory bowel diseases. The potential roles played by fatty acid intake, serum leptin, and nitric oxide in the promotion of intestinal inflammation in Crohn's disease and ulcerative colitis will be reviewed. In addition, important advances in the areas of bone disease, vitamin deficiency, growth failure, and home parenteral nutrition will be discussed.

Cytokines and inflammatory bowel disease: a review

The etiology and pathogenesis of inflammatory bowel disease (IBD) remains an area under intense investigation. Cytokine secretion, which is important in the regulation of normal gastrointestinal immune responses, appears to be dysregulated in IBD. In Crohn's disease, there appears to be an excessive T(H)1 T-cell response to an antigenic stimulus, leading to increased levels of proinflammatory cytokines, such as interferon-gamma (IFN-gamma), interleukin (IL)-12, IL-1, IL-6, and tumor necrosis factor-alpha (TNF-alpha). In ulcerative colitis, a T(H)2 T-cell response appears to be the pathological process responsible for the inflammatory disease. New and innovative therapeutic strategies targeting cytokines, such as TNF-alpha, are producing some promising results in animal and human studies. As more is learned about the complex cytokine interactions in IBD, more effective treatments will undoubtedly ensue.

Wheat bran decreases aberrant crypt foci, preserves normal proliferation, and increases intraluminal butyrate levels in experimental colon cancer

BACKGROUND

Dietary wheat bran protects against colon cancer, but the mechanism(s) of this effect is not known. Butyrate, produced by colonic bacterial fermentation of dietary polysaccharides, such as wheat bran, induces apoptosis and decreases proliferation in colon cancer cell lines. Whether similar effects occur in vivo is not well defined. We hypothesized that wheat bran's antineoplastic effects in vivo may be mediated in part by butyrate's modulation of apoptosis and proliferation.

METHODS

Male F344 rats were fed wheat bran-supplemented or an isocaloric, isonitrogenous fiber-free diet. Rats were treated with one dose of the carcinogen azoxymethane or vehicle with sacrifice after 5 days (tumor initiation); or two doses (days O and 7) with sacrifice after 56 days (tumor promotion). Study variables included fecal butyrate levels and the intermediate biomarkers of colon carcinogenesis, aberrant crypt foci (ACF), and changes in crypt cell proliferation and apoptosis.

RESULTS

During tumor initiation, wheat bran produced greater apoptosis (p = .01), a trend toward less proliferation, and preserved the normal zone of proliferation (p = .01). At tumor promotion, wheat bran decreased the number of ACF (proximal colon, p = .005; distal colon, p = .047) and maintained the normal proliferative zone. The fiber-free diet shifted the zone of proliferation into the premalignant pattern in both studies. Wheat bran produced significantly higher fecal butyrate (p = .01; .004, .00001) levels than the fiber-free diet throughout the tumor promotion study.

CONCLUSIONS

Wheat bran increased apoptosis and controlled proliferation during tumor initiation and resulted in decreased ACF. Wheat bran's antineoplastic effects occurred early after carcinogen exposure, and were associated with increased fecal butyrate levels.

Use of gastrostomy and combined gastrojejunostomy tubes for enteral feeding

Recent economic changes in health care delivery have led to more frequent feeding by tube enterostomy. Over the last two decades percutaneous endoscopic gastrostomy (PEG) has been established as the standard method for long-term enteral access for nutrition, though operative gastrostomy remains indicated in a few conditions. Additionally, the combined gastrojejunostomy tube is indicated in selected patients in need of concomitant access to the jejunum and gastric decompression. This report reviews data regarding the safety and efficacy of the PEG tube and the indications for operative gastrostomy. Complications of feeding tubes and strategies to avoid or remedy them are also discussed. More recent techniques, including laparoscopic gastrostomy and jejunal access via the stomach, are reviewed as are some ethical concerns regarding the appropriateness of feeding enterostomies in certain patients.

Nutrition and inflammatory bowel disease

This article reviews the nutritional aspects of inflammatory bowel disease (IBD) including the mechanisms and manifestations of malnutrition and the efficacy of nutritional therapies. Nutrient deficiencies in patients with IBD occur via several mechanisms and may complicate the course of the disease. Nutritional status is assessed by clinical examination and the use of nutritional indices such as the Subjective Global Assessment of nutritional status. Nutritional intervention may improve outcome in certain individuals; however, because of the costs and complications of such therapy, careful selection is warranted, especially in patients presumed to need parenteral nutrition.

Nutritional and metabolic advances in inflammatory bowel disease

Crude measurements of nutritional status, such as body weight, are inadequate to assess the severity and consequence of malnutrition among inflammatory bowel disease patients. Functional deficiency resulting in osteopenia and muscle weakness have been demonstrated in these patients when compared to controls. Manipulating micronutrient and essential fatty acid intake may affect the degree of inflammation and functional status in these patients. Despite evidence that colonocyte oxidation of butyrate is impaired, pharmacologic doses of butyrate have been disappointing. Much of the general population fails to achieve the recommended daily allowance of lipid, micronutrients and fibre. Even in the absence of specific dietary manipulation, patient education regarding a prudent diet is sorely needed.

Mechanisms of intestinal epithelial cell injury and colitis in interleukin 2 (IL2)-deficient mice

Epithelial cell (EC) injury is a feature of all inflammatory bowel disorders (IBD). Although the mechanisms of EC injury are incompletely understood, it has been proposed that T-cell-mediated cytotoxicity and production of inflammatory cytokines are involved. This hypothesis was tested using the interleukin 2-deficient (IL2-/-) mouse model of IBD and cultures of primary colonic EC to determine if abnormal cytokine production or cytotoxicity by colonic T cells cause EC injury. Although capable of cell-mediated killing of allogeneic target cells, IL2-/- colonic T cells were unable to lyse syngeneic colonic EC. During disease progression, large numbers of IL4, TNF-alpha, and IFN-gamma-producing CD4+ and CD8+ cells accumulated within the intraepithelial spaces and lamina propria of the colon of IL2-/- mice. Although colonic EC expressed receptors for IFN-gamma and TNF-alpha, these cytokines did not adversely affect EC viability or growth in vitro consistent with these cytokines not being the primary mediators of EC injury in IBD. Our novel colonic EC culture system provides an in vitro accessible system in which to investigate further the nature of EC-lymphocyte interactions.

Intestinal adaptation after extensive small bowel resection: differential changes in growth and insulin-like growth factor system messenger ribonucleic acids in jejunum and ileum

The distal small bowel exhibits greater adaptive growth than proximal segments after partial small intestine resection. To explore this process, we evaluated adaptive cellularity, intestinal insulin-like growth factor (IGF) system messenger RNA (mRNA) transcripts, and effects of recombinant IGF-I treatment in jejunum and ileum of adult rats. Gastrostomy-fed animals underwent 80% jejuno-ileal resection or intestinal transection and reanastomosis without resection, followed by infusion of human recombinant IGF-I (2.4 mg/kgXday) or vehicle. After 7 days, resected rats demonstrated modest adaptive growth in jejunum and marked cell proliferation in ileum. Resection increased IGF-I mRNA in both jejunum (183%) and ileum (249%) and up-regulated IGFBP-4 mRNA levels in both tissues. IGFBP-3 mRNA fell significantly in ileum after resection. IGF-I infusion modestly increased ileal cellularity after resection, but had no effect in jejunum. IGF-I markedly increased IGFBP-3 mRNA levels in jejunum after both transection and resection. These data confirm that bowel resection induces greater adaptive growth in ileum than jejunum. IGF-I administration modestly increases ileal, but not jejunal, growth after resection. Increased levels of intestinal IGF-I and IGFBP-4 mRNA suggest roles for IGF-I and IGFBP-4 in mediating small bowel adaptation. Higher levels of jejunal IGFBP-3 mRNA may be related to limited jejunal vs. ileal growth after extensive jejuno-ileal resection.

Total proctocolectomy and ileoanal pouch: the role of contrast studies for evaluating postoperative leaks

BACKGROUND

To assess the role of contrast enemas for the evaluation of leaks in symptomatic and asymptomatic patients after the first stage of restorative proctocolectomy.

METHODS

We reviewed the findings of 59 contrast enemas in 40 patients who underwent total proctocolectomy with creation of an ileoanal pouch and a proximal diverting ileostomy. Thirty-seven patients initially underwent routine contrast studies of the ileoanal pouch, and three underwent contrast studies because of suspected fistulas or obstruction. Medical records were also reviewed to determine the clinical presentation and course of these patients.

RESULTS

Of 37 patients who underwent routine postoperative contrast enemas, 33 (89%) had normal studies, three (8%) had clinically silent leaks (including two blind-ending tracks from the ileoanal anastomosis and one from the pouch), and one (3%) had pouchitis. In all three patients with unsuspected leaks, ileostomy closure was delayed. In two other patients with abdominal pain and fever, contrast enemas revealed leaks from the ileoanal pouch and distal ileum, respectively. The remaining patient had a contrast enema because of abdominal pain and distention; this patient had a distal ileal obstruction due to adhesions.

CONCLUSIONS

Routine postoperative contrast studies revealed clinically silent leaks from the ileal J pouch or ileoanal anastomosis in three of 37 patients (8%) after the first stage of restorative proctocolectomy. Our findings suggest that routine contrast enema can detect clinically silent leaks after this surgery.

Nutrient pharmacotherapy for gut mucosal diseases

The use of nutrients for pharmacotherapy is a recent advance in the treatment of gastrointestinal disorders or alterations of gut function and structure. Nutrients may have a direct effect on the gut, or may enhance the response to medications. Alternatively, pharmacologic agents may improve the absorption of nutrients. Potentially, pharmacotherapy may be an adjunct to the traditional approach used in the treatment of compromised patients.

Advances in nutrition and gastroenterology: summary of the 1997 A.S.P.E.N. Research Workshop

BACKGROUND

The 1997 A.S.P.E.N. Research Workshop was held at the annual meeting in San Francisco, on January 26, 1997. The workshop focused on advances in clinical and basic research involving the interface between nutrient and luminal gastroenterology.

METHODS

Presentations on the genetic regulation of gastrointestinal development, the molecular biology of small intestinal adaptation, the effect of nutrition support on intestinal mucosal mass, the relationship between nutrition and gastrointestinal motility, nutrient absorption, and gastrointestinal tract substrate metabolism were made by the preeminent leaders in the field.

RESULTS

The investigators presented an insightful analysis of each topic by reviewing data from their own laboratories and the published literature.

CONCLUSIONS

This workshop underscored the important interactions between nutrition and luminal gastroenterology at the basic science, metabolic/physiologic, and clinical levels. The integration of presentations from the different disciplines provided a unique interaction of information and ideas to advance our understanding of nutrition and gastrointestinal tract.

Efficient adenoviral-mediated murine neonatal small intestinal gene transfer is dependent on alpha(v) integrin expression

BACKGROUND/PURPOSE

Clinical application of gene therapy for patients who have inflammatory bowel disease or short bowel syndrome will require the development of new strategies to improve the efficiency of small intestinal gene transfer. Previously, the authors developed a method for adenoviral-mediated small intestinal gene transfer in vivo in neonatal and adult mice. The present study evaluates the hypothesis that the integrins alpha(v)beta3 and alpha(v)beta5, the secondary receptors for adenoviral internalization, play a facilitative role in neonatal murine adenoviral-mediated small intestinal gene transfer.

METHODS

Immunohistochemical techniques identified the integrin alpha(v)beta3 and the integrin subcomponents alpha(v), beta3, and beta5 in neonatal and adult small intestine. The effects of integrin receptor antagonists on transgene expression was also studied in our neonatal model of adenoviral-mediated small intestinal gene transfer in vivo.

RESULTS

Gene transfer was significantly decreased by the addition of integrin receptor antagonists versus control peptide. Integrin alpha(v)beta3 and integrin subcomponent alpha(v), beta3, and beta5 are expressed in neonatal and adult small intestine. Integrin antagonists administered simultaneously blocked efficient adenoviral-mediated neonatal small intestinal gene transfer in vivo compared with control peptide.

CONCLUSION

Strategies to upregulate integrin expression may improve adenoviral-mediated small intestinal gene transfer.

Butyrate and the colonocyte. Production, absorption, metabolism, and therapeutic implications

Butyrate, a SCFA generated by microbial fermentation of dietary substrates, is produced in the colon of humans and may influence colonic disease. It is possible to manipulate the diet in order to enhance levels of butyrate in various regions of the large intestine. Butyrate is absorbed by colonocytes in the proximal colon via passive diffusion and by active transport mechanisms which are linked to various ion exchange transporters. In the distal colon, the main mechanism of absorption is passive diffusion of the lipid-soluble form. Butyrate and other SCFA are important for the absorption of electrolytes by the large intestine and may play a role in preventing certain types of diarrhea. The mechanism by which butyrate and other SCFA exerts control over fluid and electrolyte fluxes in the colon is not well delineated though it may occur through an energy generated fuel effect, the up-regulation of various electrolyte transport systems, as well as possible effects on neuroendocrine factors. Butyrate has been shown to have beneficial effects on some colonic pathologies. This SCFA may be protective against colorectal neoplasia. Butyrate regulates colonic motility, increases colonic blood flow and may enhance colonic anastomosis healing. Butyrate may reduce the symptoms from ulcerative colitis and diversion colitis and it may prevent the progression of colitis in general. Further investigations are needed to confirm these findings in controlled, randomized, double blinded clinical studies.

Butyrate inhibits deoxycholate-induced increase in colonic mucosal DNA and protein synthesis in vivo

PURPOSE

Crypt surface hyperproliferation is an intermediate biomarker of colon cancer risk. In vitro studies indicate that the short-chain fatty acid and antineoplastic agent butyrate may reverse the crypt surface hyperproliferation induced by the secondary bile acid and tumor promoter, deoxycholate. We hypothesized that butyrate may reverse deoxycholate-induced crypt surface proliferation in vivo.

METHODS

Thirty-one Sprague-Dawley rats (250-300 g) underwent surgical isolation of the colon and 24-hour luminal instillation of either sodium chloride, butyrate, deoxycholate, or butyrate plus deoxycholate (all solutions, 2 ml; pH 7; total sodium = 20 mM). Study variables included colon weight, mucosal DNA, mucosal protein, and proliferating cell nuclear antigen immunohistochemistry, labeling of which was determined in five crypt compartments from base to surface (12 crypts per rat). Labeling indexes were calculated as proliferating cell nuclear antigen immunohistochemistry-labeled cells divided by total counted cells in the whole colonic crypt and each of five crypt compartments. The phi(h) value (an index of premalignant risk) was calculated as the ratio of labeled cells in the two surface compartments divided by the total labeled cells.

RESULTS

Deoxycholate significantly increased colon wet weight, mucosal protein, total crypt labeling indexes, crypt surface labeling indexes, and the phi(h) value and raised the mucosal DNA content. Butyrate alone slightly reduced total mucosal DNA and protein content. The combination of butyrate plus deoxycholate significantly decreased mucosal DNA and tended to reduce mucosal protein compared with deoxycholate alone. In contrast to prior in vitro findings, butyrate plus deoxycholate did not reverse the deoxycholate-induced surface hyperproliferative changes as measured by proliferating cell nuclear antigen labeling.

CONCLUSIONS

Because co-treatment with butyrate plus deoxycholate inhibits deoxycholate-induced increases in total mucosal DNA and protein content, we conclude that butyrate may play a role in maintaining the proliferative balance of the colonic mucosa, in vivo. However, co-treatment with butyrate plus deoxycholate does not reverse the deoxycholate-induced increases in colon weight and proliferating cell nuclear antigen labeling indexes under the studied experimental conditions.

Glutamine protects function and improves preservation of small bowel segments

BACKGROUND

Improved organ preservation is essential for the success of small bowel transplantation. Small bowel is usually preserved in UW (University of Wisconsin) solution which does not contain glutamine (Gln), the principal fuel for the enterocyte. We hypothesized that Gln-supplemented UW would improve mucosal function and structure of cold preserved small intestine.

MATERIALS AND METHODS

Jejunum (40 cm) was harvested from Lewis rats and preserved for 18 hr at 4 degrees C in saline; UW solution only; UW with 1, 2, or 4% Gln; and UW containing 1, 2, or 4% isonitrogenous balanced nonessential amino acids (NEAA). 14C glucose transport, mucosal protein, mucosal maltase and alkaline phosphatase, jejunal villous height, and histologic damage were measured.

RESULTS

UW with 2% Gln significantly increased glucose transport and mucosal protein when compared to the 2% NEAA and UW-only groups. Two percent Gln significantly decreased histologic damage of jejunum following cold preservation. Increasing Gln to 4% did not significantly increase its efficacy when compared to the UW with 2% Gln group. There were no significant differences in the activities of mucosal maltase and alkaline phosphatase among the various treatment groups.

CONCLUSIONS

The addition of Gln, optimally provided at a concentration of 2%, to UW solution may protect the preserved small bowel segments from cold ischemic injury and improve mucosal function.

Increased expression of tissue cytokines in graft-versus-host disease after small bowel transplantation in the rat

BACKGROUND

Graft-versus-host disease (GVHD) occurs in the recipient after small bowel transplantation (SBT). Proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and interleukin 6 (IL-6), may be important mediators of GVHD. Increased expression of these cytokines might precede the clinical manifestations of GVHD induced by SBT.

METHODS

Heterotopic SBT was performed using Lewis donors into Lewis x Brown Norway F1 (LBN-F1) recipients. The isograft control was performed from LBN-F1 into LBN-F1. Animals were killed on the 5th and 11th postoperative day (POD). mRNA was isolated from recipient native small bowel, colon, spleen, liver, and mesenteric lymph nodes and from nonsurgical controls as baseline. Semiquantitative reverse transcriptase polymerase chain reaction was performed to amplify mRNA transcripts for TNF-alpha, IFN-gamma, and IL-6 using alpha32P-dATP incorporation. Clinical signs, histologic assessment, and cytokine expression were correlated.

RESULTS

On POD 5, there were neither clinical signs nor histologic features of GVHD, but mRNA expression of TNF-alpha and IL-6 in small bowel, IL-6 in spleen, and IFN-gamma in mesenteric lymph nodes were significantly increased in allograft animals when compared with normal and isograft tissues. On POD 11, both the clinical signs and histologic features of GVHD were seen, and TNF-alpha and IL-6 in native small bowel, TNF-alpha in colon, IFN-gamma in spleen, and IL-6 in mesenteric lymph nodes were significantly increased in allograft animals when compared with that in normal and isograft tissues.

CONCLUSIONS

In conclusion, TNF-alpha, IFN-gamma, and IL-6 expression precede clinical onset and histologic evidence of GVHD in specific tissues. Therefore, increased expression of these cytokines is correlated with the development of GVHD in this model of SBT.

Deoxycholate inhibits in vivo butyrate-mediated BrDU labeling of the colonic crypt

The short-chain fatty acid butyrate (NaBu) selectively increases colonic crypt base proliferation and inhibits "premalignant" crypt surface hyperproliferation while the secondary bile acid deoxycholate (DCA) induces surface hyperproliferation, in vitro. We hypothesized that NaBu and DCA have similar selective and antagonistic effects on the colonic crypt proliferative pattern, in vivo. Fifty-six adult SD rats underwent surgical isolation of the colon and 24-hr intraluminal instillation with physiological (10 mM) and pharmacological (25 mM) levels of butyrate alone or combined with a physiological DCA level (5 microM). Bromodeoxyuridine-labeling indices (LI) were determined as labeled cells divided by total cells, for the whole crypt and five crypt compartments from base to surface. Treatment with NaBu increased total LI when compared to NaCl. This effect was significant only at the crypt base. Both doses of NaBu resulted in similar LI with no further response at the higher concentration. In contrast to prior in vitro studies, DCA alone at this concentration did not affect LI, but when combined with NaBu, DCA inhibited the effects of NaBu at the crypt base and surface. The conclusions are: (1) the in vivo proliferative effects of NaBu are selective to the crypt base, (2) an in vivo low physiological DCA level does not promote crypt surface hyperproliferation but does inhibit butyrate's proliferative effect, and (3) NaBu and DCA interact in a complex and antagonistic manner to selectively modulate crypt base and surface proliferation, in the rat colon, in vivo. These findings may have clinical relevance since colonic levels of NaBu and DCA are affected by diet.

Summary of round table conference: gut dysfunction in critical illness

There is recent evidence that intestinal function is an important determinant in the outcome of critically ill patients. The barrier function is an important characteristic of the gut. Its workings are complex and it consists of epithelial, molecular, and immune components. The pathogenesis of gut dysfunction among critically ill patients is multifactorial, consisting of the quality and quantity of microorganisms, the permeability of the epithelium, and the extent of the vascular perfusion. A practical bedside measure of gut dysfunction is intolerance to enteral feedings. Potential therapies for gut dysfunction include the use of vasoactive drugs to enhance perfusion, selective decontamination to decrease bacteria and endotoxin, and the early and frequent administration of enteral nutrients.

Changes in human mucosal gamma delta T cell repertoire and function associated with the disease process in inflammatory bowel disease

BACKGROUND

Although gamma delta T cells are a major component of the human intestinal mucosa, it is not clear what role they play in mucosal immunity or if they are involved in the disease process of inflammatory bowel disease (IBD).

MATERIALS AND METHODS

Flow cytometry and reverse transcriptase-polymerase chain reaction (RT-PCR) assays were used to identify quantitative and qualitative changes in the repertoire of gamma delta T cells present in surgical and/or biopsy samples or normal and inflamed colon from individual patients with ulcerative colitis (UC) or Crohn's disease (CD). Cytokine production and the ability to adhere to and interact with colonic fibroblasts were used to compare the functional properties of gamma delta T cells isolated from the normal and diseased colonic mucosa.

RESULTS

Increased numbers of gamma delta T cells localized in areas of inflammation and tissue injury were found in the majority of patients, irrespective of the type of IBD present. This expansion was attributable to an increase in V delta 1+ cells expressing a V delta 1-(D delta 3)-J delta 1-encoded T cell receptor and was seen in patients with severe disease as well as those with newly diagnosed or less severe forms of IBD. Among T cells present in the inflamed mucosa of patients with CD, gamma delta T cells, particularly V delta 1+ cells, were a major source of the proinflammatory cytokine interferon-gamma and could interact with colonic fibroblasts.

CONCLUSIONS

Our results demonstrate that the chronic inflammatory immune response characteristic of IBD is associated with distinct changes in the number, distribution, composition, and function of mucosal gamma delta T cells. Through the production of cytokines and physical interaction with other cells, gamma delta T cells can perform an immunoregulatory function and contribute to the pathophysiology of IBDs.

Nutrition and ulcerative colitis

The role of diet in the aetiology and pathogenesis of ulcerative colitis (UC) remains uncertain. Impaired utilization by colonocytes of butyrate, a product of bacterial fermentation of dietary carbohydrates escaping digestion, may be important. Sulphur-fermenting bacteria may be involved in this impaired utilization. Oxidative stress probably mediates tissue injury but is probably not of causative importance. Patients with UC are prone to malnutrition and its detrimental effects. However, there is no role for total parenteral nutrition and bowel rest as primary therapy for UC. The maintenance of adequate nutrition is very important, particularly in the peri-operative patient. In the absence of massive bleeding, perforation, toxic megacolon or obstruction, enteral rather than parenteral nutrition should be the mode of choice. Nutrients may be beneficial as adjuvant therapy. Butyrate enemas have improved patients with otherwise recalcitrant distal colitis in small studies. Non-cellulose fibre supplements are of benefit in rats with experimental colitis. Eicosapentaenoic acid in fish oil has a steroid-sparing effect which, although modest, is important, particularly in terms of reducing the risk of osteoporosis, but it seems to have no role in the patient with inactive disease. gamma-Linolenic acid and anti-oxidants also are showing promise. Nutrients may also modify the increased risk of colorectal carcinoma. Oxidative stress can damage tissue DNA but there are no data published at present on possible protection from oral anti-oxidants. Butyrate protects against experimental carcinogenesis in rats with experimental colitis. Folate supplementation is weakly associated with decreased incidence of cancer in UC patients when assessed retrospectively. Vigilance should be maintained for increased micronutrient requirements and supplements given as appropriate. Calcium and low-dose vitamin D should be given to patients on long-term steroids and folate to those on sulphasalazine.

Perforated villous adenoma of the cecum: report of a case

Villous adenomas are common neoplasms of the colon, often causing anemia or hemoccult positive stools. Less typically, these lesions may result in abdominal pain, melena, obstruction, or change in bowel habits. Intussusception may occur, but this complication is unusual in adults. Spontaneous bowel perforation attributable to colonic polyps has not been previously reported. We present here the first reported case of an adenomatous polyp with bowel perforation and bladder involvement.

Gut adaptation and the insulin-like growth factor system: regulation by glutamine and IGF-I administration

Intestinal adaptation after extensive small bowel resection in rats is augmented by the provision of diets supplemented with the amino acid glutamine (Gln) or by administration of insulin-like growth factor-I (IGF-I). The goal of this study was to investigate potential synergistic effects of Gln and IGF-I on postresection ileal hyperplasia. Rats underwent 80% small bowel resection (SBR) and then were fed low-Gln or L-Gln-enriched diets and subcutaneously given recombinant human IGF-I or vehicle for 7 days. Gln and IGF-I each significantly enhanced adaptive ileal hyperplasia (DNA content) compared with rats receiving vehicle and low-Gln diet. Ileal DNA content was highest when IGF-I was administered together with Gln supplementation. Combined IGF-I plus Gln synergistically increased ileal weight and protein content. This was associated with higher plasma concentrations of IGF-I and Gln than observed when IGF-I or Gln was given individually. Ileal IGF-I mRNA expression rose nearly twofold during gut adaptation after SBR; this response was augmented with IGF-I administration but was unaltered by Gln feeding. In contrast, dietary Gln, but not IGF-I therapy, prevented a decrease in hepatic IGF-I mRNA induced by SBR. We conclude that parenteral IGF-I and enteral Gln have both individual and synergistic effects on ileal adaptation after massive small intestinal resection. These findings support the concept that specific gut-trophic nutrients and growth factors may be combined to enhance intestinal adaptation and possibly reduce the severity of short bowel syndrome after intestinal resection.

Butyrate inhibits seeding and growth of colorectal metastases to the liver in mice

BACKGROUND

The short-chain fatty acid butyrate inhibits growth of colorectal carcinoma cells in vitro. Mevalonate, a short-chain fatty acid structurally and metabolically related to butyrate, is important in signal transduction and is essential for cell growth. We investigated butyrate's effects on seeding and growth of colorectal tumor cells metastatic to the liver in vivo and hypothesized that butyrate's antiproliferative effects are associated with inhibition of mevalonate-mediated cell growth.

METHODS

Hepatic metastases were induced by injecting 1 x 10(5) MC-26 (N-methyl-N-nitrosourea-induced murine colorectal carcinoma) cells into the spleen of BALB/c mice. Mice were treated with a continuous intravenous infusion of butyrate (2 gm/kg/day) for 7 days starting 24 hours before tumor cells were injected. Study variables included liver weight and number of hepatic surface metastases. Proliferation studies on MC-26 cells were performed in vitro to examine the effects of butyrate alone or combined with mevalonate or mevastatin (an inhibitor of mevalonate synthesis).

RESULTS

Butyrate reduced seeding and growth of colorectal tumor cells in vivo. Mevalonate diminished butyrate's antiproliferative action in vitro, whereas mevastatin potentiated this effect.

CONCLUSIONS

These studies (1) show that butyrate inhibits seeding and growth of hepatic colorectal metastases in vivo, (2) associate butyrate's antiproliferative effects with inhibition of mevalonate-mediated cell growth, and (3) indicate that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors may have synergistic antiproliferative effects when combined with butyrate.

In vivo crypt surface hyperproliferation is decreased by butyrate and increased by deoxycholate in normal rat colon: associated in vivo effects on c-Fos and c-Jun expression

BACKGROUND

Studies on colon carcinogenesis suggest that the short-chain fatty acid butyrate may be protective, whereas the secondary bile acid deoxycholate may promote tumor development. Crypt surface hyperproliferation is regarded as a biomarker of colon cancer risk and can be modulated in vitro by the differentiation inducer butyrate and the tumor promoter deoxycholate. We hypothesized that butyrate decreases and deoxycholate increases crypt surface proliferation in vivo and that these effects are mediated by changes in the expression of the protooncogenes c-Fos and c-Jun, which are known to regulate proliferation and differentiation.

METHODS

Twenty-five adult Sprague-Dawley rats underwent colonic isolation and 24-hour intraluminal instillation of 10 mmol/L sodium chloride, 10 mmol/ L sodium butyrate, or 10 mmol/L sodium deoxycholate. Proliferation of the whole crypt and five crypt compartments from base to surface was assessed by proliferating cell nuclear antigen immunohistochemistry. The øh value, an index of "premalignant" hyperproliferation, was calculated as the ratio of labeled cells in the two surface compartments divided by the labeled cells in the entire crypt. Expression of c-Fos and c-Jun was evaluated by Western blot.

RESULTS

Crypt surface proliferation and the øh value were significantly decreased by butyrate and increased by deoxycholate. Butyrate increased colonic expression of c-Jun, whereas deoxycholate significantly induced c-Fos.

CONCLUSIONS

The in vivo effects on surface proliferation are consistent with a potential protective [corrected] role for butyrate and a promotive role for deoxycholate in colon carcinogenesis. The concurrently observed effects on colonic c-Jun and c-Fos expression represent a novel finding and suggest that direct or indirect modulation of protooncogene expression may be the mechanism by which these dietary byproducts regulate proliferation in vivo.

Protective effects of glutamine enriched diets on acute actinic enteritis

Radiotherapy plays an important role in cancer treatment, although it may cause collateral effects and sever complications due to cellular damage of peritumoral tissues. Recently different nutritional resources have been indicated to achieve intestinal protection during cancer irradiation. The aim of this study was to set the role of glutamine in acute actinic enteritis prevention. Sixty-five Wistar male rats (200 g) were maintained in individual metabolic cages, where body weight and food ingestion were carefully monitored daily. The animals were chosen at random in three groups and fed isocaloric and isoproteid diets: 1) CRt (23)-polymeric-casein diet (CD); 2) GRt (22)-polymeric-casein diet supplemented with 2% glutamine (GD), and 3) ERt (20)--elemental diet supplemented with 2% glutamine (ED). After an adaptation period (seven days), all rats received 1500 cGy of abdominal radiation in five equal daily doses of 300 cGy. After three days post radiation the rats were submitted to jejunal perfusion test with polyethylene-glicol 4000. Finally, small bowel and colon were resected for histological evaluation. It was observed that ERt group had greater average daily food intake than CRt and GRt groups during all periods (p < 0.05). All rats had equal weight gain during adaptation period; during irradiation all the animals had weight loss, but ERt group had smaller weight loss than CRt. All rats recovered weight after irradiation, and ERt group presented better results than the others (p < 0.05). Sodium transepithelial transport average values (mEq/min/cm) were negative and not statistically different in all groups. Small bowel histological evaluation in ERt and GRt rats were better than CRt rats, by preserving mucosal cellularity and increasing mitosis number and villi length (p < 0.05). Simultaneously, ERt group had greater number of rats with normal villuscrypt relation than CRt of CRt groups (p < 0.05). Large bowel histological data showed that the average crypt's length in ERt and GRt rats were greater than in CRt ones (p < 0.05). By the present work, an elemental diet enriched with 2% glutamine favored greater food ingestion and lessened weight loss during and after radiotherapy. Glutamine-supplemented polymeric or elemental diets given to rats before, during and after abdominal radiotherapy showed protective effects against radiation injury, by supporting mucosal structure and recovery.

Butyrate and the colonocyte. Implications for neoplasia

Butyrate is produced in the colon of mammals as a result of microbial fermentation of dietary fiber, undigested starch, and proteins. Butyrate may be an important protective agent in colonic carcinogenesis. Trophic effects on normal colonocytes in vitro and in vivo are induced by butyrate. In contrast, butyrate arrests the growth of neoplastic colonocytes and inhibits the preneoplastic hyperproliferation induced by some tumour promoters in vitro. We speculate that selective effects on G-protein activation may explain this paradox of butyrate's effects in normal versus neoplastic colonocytes. Butyrate induces differentiation of colon cancer cell lines. It also regulates the expression of molecules involved in colonocyte growth and adhesion and inhibits the expression of several protooncogenes relevant to colorectal carcinogenesis. Additional studies are needed to evaluate butyrate's antineoplastic effects in vivo and to understand its mechanism(s) of action.

Resection-induced colonic adaptation is augmented by IGF-I and associated with upregulation of colonic IGF-I mRNA

The effects of exogenous insulin-like growth factor-I (IGF-I) on colonic adaptation were examined in male Sprague-Dawley rats (n = 60, 225-275 mg) after either a 60% small bowel and cecal resection (RX) or mid-small bowel transection with reanastomosis (TX). Animals received a 7-day treatment with either IGF-I (2.4 mg.kg-1.day-1) or vehicle (V; 0.1 mol/l acetic acid). Body weight decreased significantly after resection (-25.6 +/- 4.0 g; P < 0.05 vs. TX/V). IGF-I treatment significantly reduced weight loss after resection (-12.4 +/- 3.8 g; P < 0.01 vs. RX/V) and induced significant weight gain after transection (15.6 +/- 4.0 g; P < 0.05 vs. TX/V). Plasma IGF-I decreased with resection (526 +/- 41 TX/V vs. 344 +/- 17 ng/ml RX/V; P < 0.01). IGF-I treatment significantly increased plasma IGF-I levels (805 +/- 100 ng/ml TX/IGF, 677 +/- 56 ng/ml RX/IGF). After resection, IGF-I treatment significantly increased colonic mucosal weight, DNA, protein content, and crypt depth when compared with resection alone (P < 0.05). Colonic water absorption, measured by an in vivo [3H]polyethylene glycol assay, was significantly increased by IGF-I treatment in resected animals (399 +/- 23 RX/IGF vs. 306 +/- 32 microliter.cm-1.h-1 RX/V; P < 0.05). Resection resulted in increased steady-state colonic IGF-I mRNA (182% of TX/V; P < 0.01) without significantly affecting IGF-I receptor mRNA expression. Regulation of IGF binding protein (BP)-3 and -4 was discoordinate, with IGFBP-3 mRNA tending to decrease with resection (67% of TX/V; P is not significant) and IGFBP-4 increasing significantly (191% of TX/V; P < 0.05). An important role for IGF-I in colonic adaptation after massive intestinal resection is indicated by 1) significantly enhanced colonic mucosal growth and water absorption with IGF-I treatment and 2) postresection upregulation of colonic IGF-I mRNA and alteration of IGFBP-3 and IGFBP-4 mRNA expression.

Colonic short chain fatty acids mediate jejunal growth by increasing gastrin

Colonic infusion of short chain fatty acids (SCFAs) is trophic to rat jejunum and is associated with raised jejunal gastrin concentration. This study examined the hypothesis that the jejunal trophic effects of colonic SCFAs are mediated in part by gastrin. Forty six adult rats underwent caecectomy to reduce endogenous production of SCFA, ileocolonic anastomosis, and placement of a colonic infusion catheter. SCFA (70 mM acetate, 35 mM propionate, 20 mM butyrate) or saline were continuously infused into the colon for seven days. Rats received either a gastrin receptor blocker (L-365,260) or a control solution and animals were killed on day 8. SCFA infused into the colon acted systemically to significantly improve jejunal structure and increase jejunal gastrin concentrations. Gastrin receptor blockade abolished effects of SCFA on jejunal DNA, protein, crypt cell proliferation, and gastrin. Gastrin blockade did not reduce SCFA induced augmentation of villous height or crypt depth. It is concluded that the jejunal trophic effects of colonically infused SCFA are mediated in part by gastrin.

Insulin-like growth factor-I (IGF-I) and glutamine improve structure and function in the small bowel allograft

IGF-I, a mitogenic polypeptide hormone, and glutamine (GLN), the preferred enterocyte fuel, singularly improve growth and structure of the small bowel isograft; however, their combined effects on intestinal allografts are unknown. This study examined the effects of IGF-I and GLN, singularly and in combination, on the structure and function of the intestinal allograft. Fifty-nine adult rats underwent resection of the distal 60% of small bowel and received either a 40-cm isograft or an allograft. Either IGF-I (2.4 mg/kg/day) or its vehicle was infused continuously by subcutaneous minipumps. An isocaloric polymeric diet with either 2% GLN or isonitrogenously balanced 2% nonessential amino acids was given continuously by gastrostomy for 10 days. Five groups were studied: isograft (ISO) alone, allograft (ALLO) alone, ALLO and GLN, ALLO and IGF-I, and ALLO and IGF-I with GLN. All recipients received Cyclosporine A (15 mg/kg, im) daily. Mucosal villus height, surface area, crypt depth, IgA, IgG, IgM, and intercellular adhesion molecule-1 (ICAM-1) plasma cells in intestinal tissue, glucose and water absorption of intestinal graft, bacterial translocation (BT) to mesenteric lymph nodes, and body weight were determined. IGF-I increased villus height, surface area (P < 0.001), crypt depth (P < 0.01), and glucose absorption (P < 0.05) compared to the ISO and ALLO groups. GLN increased only crypt depth when compared to the ALLO group (P < 0.01). Both IGF-I and GLN independently decreased BT to MLN (P < 0.05) and, in combination, enhanced water absorption (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin-like growth factor-I improves mucosal structure and function in transplanted rat small intestine

The transplanted small intestine develops significant mucosal atrophy, impaired nutrient and water absorption, and increased bacterial translocation to mesenteric lymph nodes in rats maintained on elemental diets or total parenteral nutrition. This study determined the effects of administration of an peptide growth factor (insulin-like growth factor-I[IGF-I]) on the mucosal structure and barrier function of rat small bowel isografts. Thirty-six adult Lewis rats underwent either resection of the distal 60% of the small bowel and proximal colon followed by a 40-cm orthotopic jejunal isograft or proximal small bowel transection and distal small bowel resection to leave an analogous length of small intestine in control animals. All rats received an isocaloric, isonitrogenous, polymeric diet (200 kcal/kg/day, 2 gN/kg/day) by gastrostomy and were infused with either IGF-I (2.4 mg/kg/day) or vehicle by osmotic pumps subcutaneously. After 10 days of treatment, jejunal crypt cell production, mucosal morphometric indices, glucose and water absorption, body weight, and bacterial translocation to mesenteric lymph nodes (MLN) were measured. Jejunal mRNA content for IGF-I, IGF-I receptor, and IGF-binding proteins 3 and 4 (IGFBP-3,4) were determined by Northern blotting. Crypt cell production, villus height, crypt depth, and villus surface area were significantly increased in control and transplanted jejunum of rats infused with IGF-I when compared to animals given vehicle alone. Additionally, jejunal glucose absorption and water absorption were significantly improved in both IGF-I groups when compared with their respective vehicle controls. IGF-I infusion increased body weight in transplanted and control animals and markedly reduced bacterial translocation to MLN after small bowel transplantation. Jejunal levels of IGF-I mRNA were significantly increased in transplanted animals when compared to transected controls. IGF-I treatment significantly increased IGFBP-3 tissue mRNA levels in both transected and transplanted animals. These results demonstrate that IGF-I administration, after small bowel transplantation, improves mucosal structure and absorptive function and reduces bacterial translocation to MLN. IGF-I may have important effects in transplanted small bowel both as an endogenous and administered growth factor.

Glutamine reduces bacterial translocation after small bowel transplantation in cyclosporine-treated rats

Bacterial translocation (BT) of enteric organisms is a major cause of sepsis in patients undergoing small bowel transplantation (SBT). Cyclosporine (CsA) may be toxic to intestinal epithelium and increase the risk of BT. Glutamine (Gln) is the preferred enterocyte fuel and maintains graft epithelial integrity in experimental SBT. This study determined the effects of CsA on mucosal structure and function of transplanted intestinal isograft and examined whether Gln-enriched diet reversed CsA-induced intestinal toxicity. Thirty-three adult Lewis rats underwent resection of the distal 60% of small bowel and received an orthotopic jejunal isograft. Rats received either elemental diet with 2% Gln or the same diet with balanced nonessential amino acids (non-Gln) by gastrostomy for 10 days. CsA (15 mg/kg, im) or olive oil was injected daily. Rats were assigned to four groups: non-Gln with vehicle, non-Gln with CsA, Gln with vehicle, and Gln with CsA. Mucosal villous height, surface area, crypt depth, 14C glucose absorption, BT to mesenteric lymph nodes (MLN), and body weight change were evaluated. The non-Gln with CsA group had the highest incidence of BT (P < 0.001). Gln groups had significantly decreased BT (P < 0.01) and increased crypt depth and villous surface area (P < 0.01) when compared to non-Gln groups. Body weight significantly decreased in CsA groups when compared to non-CsA groups (P < 0.01). These results indicate at CsA significantly decreased body weight and increased BT without decreasing mucosal structure and glucose absorption of intestinal isografts.(ABSTRACT TRUNCATED AT 250 WORDS)

Pectin improves colonic function in rat short bowel syndrome

Short bowel syndrome is characterized by weight loss, diarrhea, and malabsorption. Pectin, a highly fermentable fiber, improves small and large bowel mucosal structure, prolongs intestinal transit, and decreases diarrhea. This study determined if the addition of citrus pectin to an enteral liquid diet (LD) improved structure and absorptive function in the rat jejunum and colon following massive intestinal resection. Twenty-one male Sprague-Dawley rats underwent placement of gastrostomy tube for isocaloric, isonitrogenous feeding and either 60% small bowel and cecal resection or small bowel transection with anastomosis. Animals in each group were then randomly and equally assigned to receive either LD (Enercal Plus, Wyeth) or LD supplemented with 2% citrus pectin for 7 days. Study variables included body weight change, percentage of stool solidity, jejunal villous height (JVH) and crypt depth, colonic crypt depth (CCD), and colonic short-chain fatty acid content (SCFA). Jejunal [14C]glucose absorption and colonic [3H]H2O absorption were measured by a dual in vivo perfusion assay. Resection significantly (P < 0.05) decreased body weight, stool solidity, and colonic SCFA content; enlarged structure (JVH, CCD); and increased absorptive function in the remaining bowel. Pectin significantly decreased (P < 0.05) body weight loss, increased (P < 0.05) stool solidity, and improved (P = 0.05) colonic water absorption following resection without significantly altering mucosal structure. It is concluded that pectin improves colonic absorptive function following massive bowel resection in the rat.

Monocyte-chemoattractant protein 1 gene expression in intestinal epithelial cells and inflammatory bowel disease mucosa

BACKGROUND

Monocyte-chemoattractant protein 1 (MCP-1) activates macrophages and increases the migration of monocytes into tissue during inflammation. It was hypothesized that MCP-1 expression is involved in intestinal inflammation.

METHODS

MCP-1 protein was detected by immunohistochemistry and immunoprecipitation. Biological activity of MCP-1 was assessed using a chemotactic assay. MCP-1 messenger RNA (mRNA) levels were measured by quantitative reverse-transcription polymerase chain reaction.

RESULTS

In normal mucosa, MCP-1 was predominantly present in surface epithelium. In contrast, inflamed mucosa from patients with ulcerative colitis or Crohn's disease contained multiple cells immunoreactive for MCP-1, including spindle cells, mononuclear cells, and endothelial cells. Furthermore, MCP-1 mRNA expression was markedly increased in inflamed intestinal biopsy specimens from patients with inflammatory bowel disease. MCP-1 was detected in isolated intestinal epithelial cells and in conditioned media from Caco-2 cells. Caco-2 cell-conditioned media stimulated monocyte chemotaxis activity that was inhibited by anti-MCP-1 antibodies. Constituitive MCP-1 mRNA levels in Caco-2 cells were up-regulated by interleukin 1 beta and down-regulated by dexamethasone.

CONCLUSIONS

In addition to lamina propria macrophages, endothelial cells, and spindle cells, intestinal epithelial cells are able to produce MCP-1. MCP-1 is expressed constitutively in the intestinal colonic mucosa and is up-regulated during inflammation.

Mediation of the trophic effects of short-chain fatty acids on the rat jejunum and colon

BACKGROUND/AIMS

Short-chain fatty acids (SCFAs) are trophic to small intestinal and colonic mucosa. This study determined whether SCFAs infused into the cecum out of continuity stimulated jejunal and colonic cellularity and whether these effects were mediated by the autonomic nervous system and/or enterotrophic hormones.

METHODS

To eliminate direct trophic effects of SCFAs in contact with mucosa, 60 rats underwent cecal isolation with placement of an infusion catheter into the proximal cecum, formation of distal cecocutaneous stoma, and restoration of intestinal continuity with ileocolonic anastomosis. Rats underwent cecal denervation or remained normally innervated and received 1 of 3 infusions for 10 days: SCFAs, saline, or no infusion. Twenty-four additional rats were assigned to the same groups but underwent infusion into the proximal colon (in circuit).

RESULTS

Cecal infusion of SCFAs into innervated rats increased (P < 0.05) jejunal DNA, villous height, surface area, crypt depth, and gastrin without increasing colonic variables. In denervated rats, SCFAs did not significantly affect these variables. However, direct intracolonic infusions of SCFAs increased (P < 0.05) colonic mucosal DNA and crypt depth.

CONCLUSIONS

Jejunotrophic effects of cecally infused SCFAs are mediated afferently by the autonomic nervous system and are associated with increased jejunal gastrin. SCFAs have local trophic effects on the colon.