Protein malnutrition alone and in combination with endotoxin impairs systemic and gut-associated immunity

Feeding an Elemental Dietvsa Milk-Based Formula Does Not Decrease Intestinal Mucosal Growth in Infant Pigs

BACKGROUND

We previously showed that the level of enteral nutrient intake determines the rate of intestinal growth in piglets. Our objective was to determine whether providing enteral nutrition in the form of elemental nutrients (glucose, amino acids, lipid [ED]) rather than cow's milk formula (lactose, protein, lipid [FORM]) reduces small intestinal growth and lactase activity.

METHODS

Three-week-old piglets were fed either ED (n = 7) intragastrically or FORM (n = 6) orally for 6 days.

RESULTS

Intestinal protein and DNA masses, villus height, and crypt depth were not different in ED and FORM pigs. Crypt cell proliferation, measured by in vivo bromodeoxyuridine labeling, was significantly (p < .05) higher (+37%) in ED than in FORM pigs. Rates of mucosal protein synthesis (%/d), measured by in vivo 2H-leucine incorporation, were higher (p < .05) in ED than FORM (147 vs 89) pigs. Circulating concentrations (pmol/L) of the intestinotrophic peptide, glucagon-like peptide-2 (GLP-2), were also higher (p < .05) in ED than in FORM (148 vs 87) pigs. The mean lactase-specific activity (micromol/min/g) in proximal and distal segments was higher (p < .05) in FORM than in ED (124 vs 58) pigs.

CONCLUSIONS

We conclude that intestinal mucosal growth and villus morphology are similar in pigs fed ED and FORM, despite higher cell proliferation and protein synthesis rates and lower lactase activity with ED. This implies that elemental diets may be as trophic as polymeric formulas to simultaneously provide nutrition and a stimulus for intestinal growth during bowel rest.

Alcoholism: A systemic proinflammatory condition

Excessive ethanol consumption affects virtually any organ, both by indirect and direct mechanisms. Considerable research in the last two decades has widened the knowledge about the paramount importance of proinflammatory cytokines and oxidative damage in the pathogenesis of many of the systemic manifestations of alcoholism. These cytokines derive primarily from activated Kupffer cells exposed to Gram-negative intestinal bacteria, which reach the liver in supra-physiological amounts due to ethanol-mediated increased gut permeability. Reactive oxygen species (ROS) that enhance the inflammatory response are generated both by activation of Kupffer cells and by the direct metabolic effects of ethanol. The effects of this increased cytokine secretion and ROS generation lie far beyond liver damage. In addition to the classic consequences of endotoxemia associated with liver cirrhosis that were described several decades ago, important research in the last ten years has shown that cytokines may also induce damage in remote organs such as brain, bone, muscle, heart, lung, gonads, peripheral nerve, and pancreas. These effects are even seen in alcoholics without significant liver disease. Therefore, alcoholism can be viewed as an inflammatory condition, a concept which opens the possibility of using new therapeutic weapons to treat some of the complications of this devastating and frequent disease. In this review we examine some of the most outstanding consequences of the altered cytokine regulation that occurs in alcoholics in organs other than the liver.

Persistent abnormal liver fibrosis after weaning off parenteral nutrition in pediatric intestinal failure

The aim of this study was to evaluate the long-term effects of pediatric intestinal failure (IF) on liver histology. Altogether, 38 IF patients (median age: 7.2 years; range, 0.2-27) underwent liver biopsy, gastroscopy, abdominal ultrasound, and laboratory tests. Sixteen patients were on parenteral nutrition (PN) after 74 PN months (range, 2.5-204). Twenty-two had weaned off PN 8.8 years (range, 0.3-27) earlier, after 35 PN months (range, 0.7-250). Fifteen transplant donor livers served as controls. Abnormal liver histology was found in 94% of patients on PN and 77% of patients weaned off PN (P = 0.370). During PN, liver histology weighted with cholestasis (38% of patients on PN versus 0% of patients weaned off PN; P = 0.003) and portal inflammation (38% versus 9%; P = 0.050) were found. Fibrosis (88% versus 64%; P = 0.143; Metavir stage: 1.6 [range, 0-4] versus 1.1 [range, 0-2]; P = 0.089) and steatosis (50% versus 45%; P = 1.000) were equally common during and after weaning off PN. Plasma alanine aminotransferase (78 U/L [range, 19-204] versus 34 [range, 9-129]; P = 0.009) and conjugated bilirubin (43 μmol/L [range, 1-215] versus 4 [range, 1-23]; P = 0.037) were significantly higher during than after weaning off PN. Esophageal varices were encountered in 1 patient after weaning off PN. Metavir stage was associated with small bowel length (r = -0.486; P = 0.002) and number of septic episodes (r = 0.480; P = 0.002). In a multivariate analysis, age-adjusted small bowel length (ß = -0.533; P = 0.001), portal inflammation (ß = 0.291; P = 0.030), and absence of an ileocecal valve (ß = 0.267; P = 0.048) were predictive for fibrosis stage.

CONCLUSION

Despite resolution of cholestasis and portal inflammation, significant liver fibrosis and steatosis persist after weaning off PN. Extensive small intestinal resection was the major predictor for liver fibrosis stage.

Two-day fasting prior to intestinal ischemia-reperfusion injury on bacterial translocation in rats

PURPOSE

The aim of this study is to verify the effect of two-day fasting prior to intestinal ischemia-reperfusion (I/R) injury on bacterial translocation (BT).

MATERIALS AND METHODS

Mail Sprague-Dawley rats were divided into four groups: group 1, control rats that underwent sham operation only; group 2, rats fasted for two days prior to sham operation; group 3, rats that underwent occlusion of mesenteric vessels for 30 min followed by reperfusion for 4 hr; and group 4, rats fasted for two days prior to the same intestinal I/R injury as in group 3. In all groups, E. coli labeled with (99m)Tc were inoculated into the terminal ileum. Two hr after inoculation of E. coli, the rats were killed. A segment of ileum was obtained for histological examination and samples of mesenteric lymph nodes (MLNs), liver, lung, blood, and spleen were obtained for radioactivity determination.

RESULTS

There were no significant differences in the intestinal mucosa and radioactivity of all samples between groups 1 and 2. Group 3 showed significantly shorter mucosa and villi, and higher radioactivity of samples, except for MLNs, compared to group 1. Group 4 showed similar mucosa and villi, but significantly higher radioactivity of samples, except for MLNs, compared to group 3.

CONCLUSION

Two-day fasting without I/R injury does not cause mucosal change and BT, but in cases following intestinal I/R injury, two-day fasting increases the susceptibility of BT to systemic organs in rats.

Optimal dietary true ileal digestible threonine for supporting the mucosal barrier in small intestine of weanling pigs

Threonine is of great importance for the maintenance of intestinal health. However, little is known about the optimal level of dietary threonine for neonates or the underlying mechanisms of its beneficial action. Our objective in this study was to determine the effects of graded levels of true ileal digestible (TID) threonine on the intestinal mucosal barrier in weanling pigs. Four groups of piglets (n = 8/group) were fed for 14 d diets containing 0.37, 0.74, 0.89, or 1.11% TID threonine. The duodenal mucosa of piglets fed the 0.37 and 1.11% TID threonine diets exhibited distorted villus architecture. Compared with pigs fed the 0.74 and 0.89% TID threonine diets, apoptosis was higher (P < 0.05) in pigs fed the 1.11% TID threonine diet. Feeding 0.37 and 1.11% TID threonine reduced (P < 0.05) concentrations of ileal acidomucins and duodenal sulfomucins, respectively, compared with the 0.74% TID threonine group. Compared with piglets fed the 0.89% TID threonine diet, the total amounts of mucins in duodenum, as well as expression of MUC2 mRNA in duodenum and jejunum, were reduced (P < 0.05) in piglets fed the 0.37 and 1.11% TID threonine diets. Collectively, these findings indicate that a deficiency or excess of dietary threonine affects the intestinal mucosal barrier and that the optimal level of dietary TID threonine for supporting gut barrier function is 0.89% for weanling pigs. These new findings have important implications for both the maintenance of normal physiological functions and the prevention of gut-related diseases in neonates.

Pretreatment with arginine preserves intestinal barrier integrity and reduces bacterial translocation in mice

OBJECTIVE

To evaluate the effects of arginine on intestinal barrier integrity and bacterial translocation (BT) in mice undergoing intestinal obstruction.

METHODS

Mice were divided into 3 groups, treated for 7 d before surgical intervention with isocaloric and isoprotein diets. The ARG group received a diet containing 2% arginine, the IO (intestinal obstruction) and Sham groups, standard chow diet. On the eighth day of treatment, all animals received diethylenetriamine pentaacetic acid (DTPA) solution labeled with 99mTechnetium (99mTc-DTPA) by gavage for intestinal permeability analysis. After 90 min, the animals were anesthetized and the terminal ileum ligated. The Sham group only underwent laparotomy. After 4, 8, and 18 h, blood was collected for radioactivity determination. Samples of ileum were collected 18 h after surgery for histological analysis. In another set of animals, BT was evaluated. After 7 d of treatment, all animals received 10(8) CFU/mL of 99mTc-E.coli by gavage; 90 min later they were submitted to the surgical procedure described above. BT was determined by the uptake of 99mTc-E.coli in blood, mesenteric lymph nodes, liver, spleen, and lungs, assessed 18 h after the surgery.

RESULTS

The intestinal permeability and BT were higher in the IO group when compared with the Sham group (P < 0.05). Arginine supplementation reduced intestinal permeability and BT to physiologic levels. Histological analysis showed mucosal ileum preservation in animals treated with arginine.

CONCLUSION

Arginine was able to preserve barrier integrity, thus reducing BT.

The influence of Peyer's patch apoptosis on intestinal mucosal immunity in burned mice

The aim of this study was to investigate the influence of apoptosis on Peyer's patches and the intestinal immunoglobulin A (IgA) response in burned mice. Sixty male Balb/c mice were randomly assigned into the sham-burn (control) group (n=30) and the burn group (n=30). The mice in the burn group received a full-thickness scald burn over 20% of the total body surface area (TBSA), on the back. At 12, 24 and 72 h, respectively, after injury, the burned mice (n=10, at every time point) were anaesthetised and their entire intestines were collected. The mice in the sham-burn group were treated with the same procedure as above, except for the burn injury. The number of Peyer's patches on every entire intestine and the total Peyer's patches cell yield were counted. The changes of lymphocyte subpopulations in Peyer's patches were measured by flow cytometry (FCM). And the levels of intestinal IgA were examined by enzyme-linked immunosorbent assay (ELISA). Fluoresceinisothiocyanate (FITC)-conjugated Annexin-tau and propidium iodide (PI) double-staining cells were analysed by FCM for apoptotic ratio in Peyer's patches. The results showed that the total Peyer's patch cell yield and the numbers of CD3, CD4, CD8 and CD19 cells were significantly decreased at 12, 24 and 72 h after injury (P<0.05), and that the intestinal IgA levels were markedly reduced at 24 and 72 h (P<0.05). On the other hand, total apoptotic ratio and all cell subpopulation apoptosis in Peyer's patches were dramatically increased at 12, 24 and 72 h after injury (P<0.05). These results indicated that severe burns led to a significant decrease in the number of Peyer's patch cells and in intestinal IgA levels, which was closely associated with strongly increased apoptosis in Peyer's patches.

Re-feeding rapidly restores protection againstHeligmosomoides bakeri(Nematoda) in protein-deficient mice

This study determined whether the timing of re-feeding of protein-deficient mice restored functional protection against the gastrointestinal nematode,Heligmosomoides bakeri. Balb/c mice were fed a 3% protein-deficient (PD) diet and then transferred to 24% protein-sufficient (PS) diet either on the day of primary infection, 10 days after the primary infection, on the day of challenge infection, or 7 days after the challenge infection. Control mice were fed either the PD or PS diet. Onset of challenge, but not primary, infection caused short-term body weight loss, anorexia and reduced feed efficiency. Weight gain was delayed in mice when re-feeding commenced on the day of challenge infection; alkaline phosphatase (ALP) was also elevated in these mice on day 28 post-challenge. In contrast, other re-feeding groups attained similar body weights to PS mice within 4 days and had similar ALP at day 28. Serum leptin was higher in PD than PS mice and positively associated with food intake. As expected, worm survival was prolonged in mice fed the PD diet. However, egg production and worm burdens were similar in all re-feeding groups to the PS mice, indicating that protein re-feeding during either the primary or challenge infection rapidly restored normal parasite clearance.

Dietary protein deficiency in pregnant mice and offspring

Previous studies suggest an association between dermal contact hypersensitivity and preterm delivery. We hypothesized that dietary protein deficiency produces cell-mediated immune hypersensitivity in pregnant animals and their offspring akin to those known to produce tissue damage. We compared the effects of feeding a 20% protein diet (controls) to those of feeding a 10% protein (deficient) diet ad libitum to pregnant BALB/c mice. We measured dermal contact sensitivity to 2,4-dinitrofluorobenzene (DNFB) by the increment in ear skin thickness (swelling) 72 h after immunization and parity by the number of viable pups delivered. Dams fed the protein-deficient diet ingested less food, gained less weight and delivered fewer viable pups than the dams fed the control diet. Greater DNFB-stimulated increment in ear skin thickness was found in the protein-deficient mothers and in their offspring than in the control mothers and their offspring. We conclude that dietary protein deficiency limits parity and induces immune hypersensitivity. These findings suggest the potential for dietary protein deficiency to activate a T-cell-mediated branch of the immune response that may put pregnant animals at risk for preterm delivery.

Dietary threonine restriction specifically reduces intestinal mucin synthesis in rats

We determined whether the steady-state levels of intestinal mucins are more sensitive than total proteins to dietary threonine intake. For 14 d, male Sprague-Dawley rats (158 +/- 1 g, n = 32) were fed isonitrogenous diets (12.5% protein) containing 30% (group 30), 60% (group 60), 100% (control group), or 150% (group 150) of the theoretical threonine requirement for growth. All groups were pair-fed to the mean intake of group 30. The mucin and mucosal protein fractional synthesis rates (FSR) did not differ from controls in group 60. By contrast, the mucin FSR was significantly lower in the duodenum, ileum, and colon of group 30 compared with group 100, whereas the corresponding mucosal protein FSR did not differ. Because mucin mRNA levels did not differ between these 2 groups, mucin production in group 30 likely was impaired at the translational level. Our results clearly indicate that restriction of dietary threonine significantly and specifically impairs intestinal mucin synthesis. In clinical situations associated with increased threonine utilization, threonine availability may limit intestinal mucin synthesis and consequently reduce gut barrier function.

Effects of ethanol on gut-associated lymphoid tissues in a model of bacterial translocation: a possible role of apoptosis

Chronic ethanol intake has been shown to be associated with immune suppression and impairment of epithelial barrier function. We investigated the effects of ethanol on intestinal immunity and its relation to bacterial translocation (BT). Male Wistar rats were assigned to one of three groups and received respective diets for 28 days. The ethanol-fed group [(EG); n=11] received a liquid diet containing 5% [volume/volume (vol./vol.)] ethanol; a pair-fed group [(PFG); n=11] received an isocaloric diet without ethanol; and a third (control) group [(CG); n=11] received water and chow ad libitum. On experimental day 29, animals in the EG and the PFG underwent distal ileum ligature and small intestine inoculation of a tetracycline-resistant Escherichia coli strain (TcR E. coli R6), by means of gastric intubation, followed by duodenal ligature. One hour after inoculation, mesenteric lymph nodes, right lobe of liver, spleen, and left kidney were excised for bacterial studies. Sections of jejunum and colon were immunostained, with the use of antibodies against immunoglobulin (Ig) A, T cells, macrophages, and proliferating cell nuclear antigen (PCNA). Apoptosis was determined by the terminal deoxynucleotidyltransferase TdT-mediated dUDP-biotin nick end labeling (TUNEL) method. Bacterial translocation rates were greater in the PFG compared with findings for the EG. Lamina propria of the jejunum of the EG showed a reduction in the densities of IgA+ cells and T cells compared with findings for the PFG and the CG. Colonic lamina propria of the EG showed reduced densities of IgA+ cells and macrophages compared with findings for the PFG and the CG. Apoptotic index was increased in the EG compared with findings for the PFG and the CG, in both jejunum and colon. Proliferation index was not significantly different among groups. Results of the current study show that chronic ethanol ingestion led to a reduction of cellular and humoral components of the intestinal mucosa, possibly by cell loss as a result of ethanol-induced apoptosis. The reduced rates of BT observed after chronic ethanol intake seem to indicate that factors irrespective of immune function might be involved in BT inhibition.

Dietary supplementation with cysteine prodrugs selectively restores tissue glutathione levels and redox status in protein-malnourished mice(1)

Protein malnutrition (PM) is a major health problem in the world. PM compromises antioxidant defense in the body. In particular, PM decreases tissue glutathione (GSH) levels. A high protein diet was found to restore tissue GSH levels in animal studies, however it is not recommended for the early phase of PM rehabilitation. Therefore, using dietary supplementation to restore tissue GSH without giving a high protein diet may be an adjunct therapy that helps improve antioxidant status during the early rehabilitation of PM. In this study, we systematically compared the efficacy of dietary supplementation of four cysteine prodrugs: N-acetylcysteine, L-2-oxo-4-thiazolidine-carboxylate, methionine, and GSH, on tissue GSH in mice fed a protein-deficient (0.5%) diet. Results showed that dietary supplementation of cysteine prodrugs to PM mice restored GSH levels in liver, lung, heart and spleen, but not in colon. GSH and GSSG levels in brain and kidney were not affected by cysteine prodrug or PM. Supplementation also restored the redox status in liver and heart (based on GSH/GSSG), and in liver and spleen (based on GSSG/2GSH reduction potential). This suggests that the restoration of GSH levels and redox status by cysteine prodrugs are tissue-specific, and that the two indicators of redox status are not always interchangeable. However, all four prodrugs exhibited similar GSH-enhancing capacities, showing no prodrug-specificity as seen in cell culture studies. In conclusion, this study provided information that may be useful in a clinical setting where a short-term oral supplementation of cysteine prodrugs is necessary for the early rehabilitation of PM patients.

Oral feeding with glutamine prevents lymphocyte and glutathione depletion of Peyer's patches in endotoxemic mice

OBJECTIVE

To determine the effect of oral glutamine feeding on lymphocyte subpopulations and glutathione metabolism in Peyer's patches (PPs) of healthy and endotoxemic mice.

SUMMARY BACKGROUND DATA

Recent data indicate that nutrients both maintain nitrogen and energy balances and modulate cell and organ function. In particular, glutamine has an impact on gut and immune function. This is of special importance in the perioperative phase.

METHODS

Female Balb/c mice were fed a glutamine-enriched diet or a control diet for 10 days. On day 7 25 microg lipopolysaccharide (LPS) or saline was injected. On day 3 after the challenge, mice were killed, total cell yield was determined, and lymphocyte subpopulations (total T cells, CD4+, CD8+ cells, and B cells) were analyzed by flow cytometry. One experimental group was treated with buthionine sulfoximine, a specific inhibitor of glutathione synthesis. The glutathione content in PPs was measured by high-performance liquid chromatography.

RESULTS

Glutamine administration led to a significant increase in total cell yield, including T and B cells, in PPs. The LPS-induced reduction of T cells (-45%) and of B cells (-30%) was significantly lower in glutamine-treated mice. Endotoxemia caused a 42% decrease of glutathione in control animals, but not in glutamine-treated animals. As with LPS, buthionine sulfoximine also lowered lymphocyte numbers and glutathione content of the PPs.

CONCLUSIONS

Administration of glutamine prevents LPS-stimulated lymphocyte atrophy in PPs, possibly by increasing the glutathione content in the PPs. Therefore, oral glutamine supply seems to be a suitable approach for improving intestinal immunity in immunocompromised patients.

Influence of enteral diets supplemented with key nutrients on lymphocyte subpopulations in Peyer's patches of endotoxin-boostered mice

BACKGROUND AND AIMS

This study was undertaken to compare the effect of different key nutrients on lymphocyte subsets of Peyer's patches (PP) and spleen in endotoxemic mice.

METHODS

Female Balb/c mice were fed over a period of 10 days either with an isocaloric and isonitrogenous control diet (Control), a glutamine enriched diet (Diet I) or a diet containing glutamine, arginine, glycine, and n-3 fatty acids (Diet II). On day 7 the mice were challenged intraperitoneally with 25 microg LPS. The lymphocyte subpopulations (B cells, T cells, CD4+ and CD8+) of PP and spleen were analysed by flow cytometry. Glutathione content of small intestinal mucosa and spleen was determined by HPLC and luminal small intestinal IgA by ELISA.

RESULTS

Both experimental diets increased the number of B and T cells in the PP and that of T cells in the spleen (P<0.01). Glutathione content in PP and spleen was higher under administration of key nutrients (P<0.05). Diet II reduced luminal small intestinal IgA content in comparison to the two other groups.

CONCLUSION

The addition of arginine, glycine and n-3 fatty acids to a glutamine supplemented diet does not enhance lymphocyte numbers in PP and spleen, but reduces intestinal IgA content.

Influence of short-term protein malnutrition of mice on the phenotype and costimulatory signals of lymphocytes from spleen and Peyer's patches

The objective of this study was to investigate the impact of short-term protein malnutrition (PM) on immunoglobulin A (IgA) production and on the number and phenotype of lymphocytes in Peyer's patches (PP) and in the spleen. Balb/c mice were fed for 4, 7, or 10 d with a protein-deficient diet (0.1% protein). We determined B lymphocytes (CD40(+)), T lymphocytes (CD3(+)), T-helper (CD4(+)), and T-suppressor (CD8(+)) cells and the expression of costimulatory signals B7.1 (CD80) and B7.2 (CD86) on B cells and their counter receptors CD28 and CTLA-4 on T cells by fluorescence-activated cell-sorting analysis. Luminal IgA concentration in the small intestine was determined by an enzyme-linked immunosorbent assay. Four days of PM caused a significant reduction in the number of mononuclear cells in the spleen (5.6 x 10(7) +/- 1 x 10(7) versus 2. 4 x 10(7) +/- 0.5 x 10(7), P < 0.001) and the PP (13 x 10(6) +/- 3 x 10(6) versus 8.6 x 10(6) +/- 2 x 10(6), P < 0.01). There was a relative increase of T cells in the spleen and a relative increase of B cells in the PP. Luminal IgA content of small intestine was significantly reduced after 4 d of PM (242 +/- 55 microg versus 173 +/- 39 microg, P < 0.05) and remained at about this level until day 10 of PM. Four days after PM, the costimulatory signals B7.1 and B7. 2 on B cells were upregulated in the PP but markedly downregulated in the spleen, which was inversely related to the expression of the counter receptor CD28 on T-helper cells. We conclude that short-term PM increases the activation of B cells in the PP but reduces the relative number and activation state of splenic B cells. Only 4 d of PM caused a systemic and intestinal immunodepression, as indicated by a markedly decreased content of mononuclear cells in the PP and the spleen.

Organ and tissue weight presentation in rat populations

Multiple ways of reporting organ weights are sources of confusion in literature. This study was designed to determine if there is a linear relationship between body weights and selected organ and tissue weights in groups of rats after different liquid feeding options. A randomized 2 x 2 x 2 factorial, randomized block design was used with 40 postpubescent male rats with two levels of feeding schedules, kilocalorie levels, and fiber contents. In addition to a skeletal muscle, 13 abdominal and thoracic organs or tissues were weighed. Pearson product-moment correlation coefficients and regression analyses were completed to determine the relationship between these weights and the final body weights. Findings support the need to use different approaches in order to accurately report various organ and tissue weights.

Factors impacting the survival of children with intestinal failure referred for intestinal transplantation

PURPOSE

The aim of this study was to analyze factors impacting on the survival of pediatric patients with intestinal failure referred for intestinal transplantation (ITx).

METHODS

Two hundred fifty-seven children (mean age, 3.4+/-0.26 years) with intestinal failure were evaluated for ITx between 1990 and 1998. All patients were dependent on total parenteral nutrition (TPN) for a mean of 31+/-2.7 months. The mean follow-up time from the date of evaluation was 9.2+/-0.9 months.

RESULTS

Eighty-two (32%) children underwent ITx with a mean waiting time of 10.1+/-1.3 months (simultaneous liver-intestinal allograft in 68% instances). Of the 175 patients who did not undergo transplantation, 120 died, 23 were lost to follow-up, and 32 are alive. Younger patients (< or =1 year) had poorer survival rates than patients older than 1 year (P<.0001). The patients with the worse prognosis were those with necrotizing enterocolitis, and those with the best prognosis were those with Hirschsprung's disease. Patients with "surgical" causes had poorer survival rates than those with "nonsurgical" causes (P<.04). Patients with bridging fibrosis or established cirrhosis had an earlier mortality than patients with portal fibrosis (P<.003). The worst survival rate was found for patients with bilirubin levels of greater than 3 mg/dL (P<.0001), plateletcounts less than 100.000/mL (P<.0001), prothrombin time greater than 15 seconds (P = .03) or partial thromboplastin time greater than 40 seconds (P<.04). Children who at the time of evaluation needed only an isolated intestinal allograft had a better prognosis than those who required a combined liver-intestine allograft (P<.00001). With multivariate analysis independent prognosis risk factors of poor outcome were hyperbilirubinemia and severity of histopathologic damage.

CONCLUSIONS

Early referral for ITx should occur before the development of liver dysfunction, taking into consideration the aforementioned risk factors that would facilitate the development and ominous evolution to liver failure.

The role of enterocytes in gut dysfunction

Stem cells in the intestinal epithelium give rise to enterocytes, goblet cells, enteroendocrine cells, and Paneth cells. Each of these cell lines plays a role in cytoprotection of the intestinal mucosa. In particular, it has been demonstrated that mature enterocytes can act as antigen presenting cells. Parenteral and enteral nutrition are used to nourish critically ill patients. However, these regimens are unfortunately associated with gut atrophy. Glutamine, the preferred intestinal nutrient, reverses this gut atrophy and plays a key role in maintaining the barrier function of the gut. Specific nutrients (putrescine, spermidine, spermine) have been used to modulate intestinal adaption. In addition, ornithine has been shown to act as a regulator of intestinal adaption. In this review, we discuss the relationship between the biology of enterocytes and failure of the gut barrier.

Incidence of nosocomial pneumonia in a medical intensive care unit and general medical ward patients in a public hospital in Bombay, India

We prospectively studied the incidence of hospital-acquired pneumonia in 1886 consecutive admissions to an 1800 bed hospital in Bombay; 991 of them to general medical wards and 895 to a 17-bed medical intensive care unit (ICU). The average bed occupancy in the general wards was 56 patients in a ward with 40 beds. Staffing in the general ward was two nurses for 56 patients, and in the ICU three nurses for 17 beds. One hundred and sixty-eight patients developed nosocomial pneumonia: 18 (1.8%) in general wards and 150 (16.7%) in the ICU. Common isolates included Pseudomonas spp (44%) and Klebsiella spp (34%). The most frequently used antibiotics were cefotaxime (34%), amikacin (25%), gentamicin (23%) and ofloxacin (13%). Crude mortality in general ward patients was 88.9 vs 14.6% in patients without pneumonia. The corresponding figures for ICU patients were 67.4 vs 37.1%; 40% of the crude mortality in ICU patients with pneumonia was attributable to the infection. Infected patients stayed an additional 5.8 days in the ICU and 6.7 days in the general ward. Costs of additional stay and antibiotics accounted for 18.6% of the ICU budget. The incidence of nosocomial pneumonia was lower than expected, despite occupancy exceeding bed capacity, low nurse:patient ratios, and extensive reuse of disposable respiratory therapy equipment. Nevertheless, nosocomial pneumonia imposes a significant financial burden on the already scarce resources available for intensive care in developing countries like India.

Use of molecular typing to investigate bacterial translocation from the intestinal tract in malnourished children with Gram-negative bacteremia

OBJECTIVE: To investigate whether translocation of intestinal Enterobacteriaceae was a likely source of bacteremia in children of 2 years or less hospitalized for fever and moderate malnutrition. METHODS: Blood and fecal cultures were obtained from 198 such children admitted in the Princess Basma Hospital (Irbid, Jordan). Enterobacteriaceae isolated from blood cultures were compared with those present in fecal cultures by genomic typing using pulsed-field gel electrophoresis. The characteristics of children whose blood and fecal strain typing patterns were not distinguishable, i.e. with documented translocation, were compared to those of children without documented translocation. RESULTS: Bacterial translocation was documented in 12 of 19 children (63%) with Enterobacteriaceae bacteremia for whom paired blood and fecal strains were available for genomic typing, and was thus the major source of these bacteremias. The clinical or biological signs of malnutrition were not significantly more pronounced in the bacteremic children with documented translocation than in those without. CONCLUSIONS: We demonstrated that bacterial translocation from the intestinal tract was the most common source of Gram-negative bacteremia in the population studied.

Gut permeability, intestinal morphology, and nutritional depletion

Nutritional depletion increases the risk for postoperative complications. The intestinal barrier may be important in the underlying pathophysiologic mechanism. In this study, 26 patients were evaluated to determine whether nutritional depletion was related to gut integrity and intestinal morphology. Nutritional depletion was estimated by calculating percentage ideal body weight (PIB) or percentage ideal fat free mass (PIFFM). To assess gut integrity, a lactulose/mannitol (L/M) test was performed. Duodenal biopsies were taken, and villous height, crypt depth, number of IgA-producing plasma cells, intraepithelial lymphocytes (IELs), and proliferating index were determined. The L/M ratio was increased, and villous height was decreased in depleted patients. Depletion was not associated with differences in the number of immune cells or proliferating index. The number of IgA-producing plasma cells was positively correlated with the L/M ratio. This study shows that nutritional depletion is associated with increased intestinal permeability and a decrease in villous height.

Role of bacterial adherence and the mucus barrier on bacterial translocation: effects of protein malnutrition and endotoxin in rats

OBJECTIVE

The purpose of the study was to investigate the potential relations between mucosal bacterial adherence, intestinal mucus and mucin content, and bacterial translocation.

SUMMARY BACKGROUND DATA

The attachment of bacteria to mucosal surfaces is the initial event in the pathogenesis of most bacterial infections that originate at mucosal surfaces, such as the gut. The intestinal mucus layer appears to function as a defensive barrier limiting micro-organisms present in the intestinal lumen from colonizing enterocytes. Consequently, studies focusing on the biology of bacterial adherence to the intestinal mucosa likely are to be important in clarifying the pathogenesis of gut origin sepsis.

METHODS

To explore the relations between intestinal bacterial adherence, mucus bacterial binding, and bacterial translocation, two models were used. One (protein malnutrition) in which profound alterations in intestinal morphology occurs in the absence of significant translocation and one (endotoxin challenge) in which bacterial translocation occurs and intestinal morphology is relatively normal.

RESULTS

Protein malnutrition was not associated with bacterial translocation and measurement of enteroadherent, mucosally associated bacterial population levels documented that the total number of gram-negative enteric bacilli adherent to the ileum and cecum was less in the protein-malnourished rats than in the normally nourished animals (p < 0.01). Furthermore, there was an inverse relation between the duration of protein malnutrition and bacterial adherence to the intestinal mucosa (r = 0.62, p < 0.002). In contrast, after endotoxin challenge, the level of enteroadherent bacteria was increased and bacterial translocation was observed. The binding of Escherichia coli to immobilized ileal mucus in vitro was decreased significantly in protein-malnourished rats, whereas E. coli binding to insoluble ileal mucus was increased in the rats receiving endotoxin.

CONCLUSIONS

This study indicates that the adherence of bacteria to the intestinal mucosal surface is an important factor in bacterial translocation, that intestinal mucus modulates bacterial adherence, and that increased levels of mucosally associated bacteria are associated with a loss intestinal barrier function to bacteria.

Intestinal permeability in kwashiorkor

Intestinal permeability can be assessed non-invasively using the lactulose-rhamnose (L-R) test, which is a reliable measure of small intestinal integrity.

AIMS

To determine risk factors for abnormal intestinal permeability in kwashiorkor, and to measure changes in L-R ratios with inpatient rehabilitation.

DESIGN

A case-control study of 149 kwashiorkor cases and 45 hospital controls. The L-R test was adapted to study kwashiorkor in Malawi, with testing at weekly intervals during nutritional rehabilitation. Urine sugars were measured by thin layer chromatography in London.

RESULTS

The initial geometric mean L-R ratios (x100) (with 95% confidence interval) in kwashiorkor were 17.3 (15.0 to 19.8) compared with 7.0 (5.6 to 8.7) for controls. Normal ratios are < 5, so the high ratios in controls indicate tropical enteropathy syndrome. Abnormal permeability in kwashiorkor was associated with death, oliguria, sepsis, diarrhoea, wasting and young age. Diarrhoea and death were associated with both decreased L-rhamnose absorption (diminished absorptive surface area) and increased lactulose permeation (impaired barrier function) whereas nutritional wasting affected only L-rhamnose absorption. Despite, clinical recovery, mean L-R ratios improved little on treatment, with mean weekly ratios of 16.3 (14.0 to 19.0), 13.3 (11.1 to 15.9) and 14.4 (11.0 to 18.8).

CONCLUSION

Abnormal intestinal permeability in kwashiorkor correlates with disease severity, and improves only slowly with nutritional rehabilitation.

Assessing the validity of adjusted urinary urea nitrogen as an estimate of total urinary nitrogen in three pediatric populations

Nitrogen excretion is a useful measurement for determining efficiency of protein utilization. Knowledge of nitrogen losses is especially important in the treatment of stressed, postsurgical, or catabolic patients, in whom optimizing the amount of nitrogen intake in the diet may spare visceral and somatic proteins and encourage anabolism. Many methods have been used to estimate total urinary nitrogen (TUN) in different patient populations. Urinary urea nitrogen (UUN) values are routinely adjusted and used by investigators who are not able to measure TUN directly by either Kjeldahl or pyrochemoluminescent methods. The rationale for the use of adjusted UUN concentrations to predict TUN is based on adult experiences. No similar experience in pediatrics has been published. We have compared TUN with adjusted UUN in a study of 250 urine samples from pediatric patients (n = 34) and normal pediatric volunteers (n = 109). Our findings suggest that adjusted UUN (determined by previously established formulas) may be of limited use in estimating TUN in neonates, infants, and critically ill pediatric patients; however, adjusted UUN may be useful in approximating TUN in healthy school-aged children. Good correlations were found between UUN and TUN for critically ill children and postsurgical neonates and infants, suggesting that these newly described regression equations (once validated) may be useful in predicting TUN from a measured UUN.

Hepatobiliary complications of total parenteral nutrition

The relationships between various hepatobiliary disorders and the administration of total parenteral nutrition (TPN) were reviewed and, in particular, the role of TPN in their pathogenesis was critically evaluated. Several clinical and pathological entities including steatosis, steatohepatitis, cholestasis, and cholelithiasis have been commonly linked to TPN, and instances of chronic decompensated liver disease have been reported. However, it is concluded that it is often difficult to extricate the effects of TPN on hepatobiliary function from many other hepatotoxic factors that may be operative in these patients. Thus, whereas considerable evidence exists to support a role fro carbohydrate or calorie excess in TPN solutions in the pathogenesis of steatosis, a loss of enteric stimulation and not TPN per se may be the primary factor in the development of cholestasis, biliary sludge, and gallstones. The apparent predilection of infants to TPN-related cholestasis may be based on the relative immaturity of the neonatal biliary excretory system.