The significance of bowel permeability

Monocyte-driven inflamm-aging reduces intestinal barrier function in females

BACKGROUND

The intestinal barrier encompasses physical and immunological components that act to compartmentalize luminal contents, such as bacteria and endotoxins, from the host. It has been proposed that an age-related decline of intestinal barrier function may allow for the passage of luminal contents into the bloodstream, triggering a low-grade systemic inflammation termed inflamm-aging. Although there is mounting evidence to support this hypothesis in model species, it is unclear if this phenomenon occurs in humans. In addition, despite being well-established that biological sex impacts aging physiology, its influence on intestinal barrier function and inflamm-aging has not been explored.

RESULTS

In this study, we observed sex differences in markers of intestinal barrier integrity, where females had increased epithelial permeability throughout life as compared to males. With age, females had an age-associated increase in circulating bacterial products and metabolites such as LPS and kynurenine, suggesting reduced barrier function. Females also had age-associated increases in established markers of inflamm-aging, including peripheral blood monocytes as well as TNF and CRP. To determine if impaired barrier function was driving inflamm-aging, we performed a mediation analysis. The results show that the loss of intestinal barrier integrity was not the mediator of inflamm-aging in humans. Instead, persistent, low-grade inflammation with age preceded the increase in circulating bacterial products, which we confirmed using animal models. We found, as in humans, that sex modified age-associated increases in circulating monocytes in mice, and that inflammation mediates the loss of intestinal barrier function.

CONCLUSION

Taken together, our results suggest that higher basal intestinal permeability in combination with age-associated inflammation, increases circulating LPS in females. Thus, targeting barrier permeability in females may slow the progression of inflamm-aging, but is unlikely to prevent it.

Modulation of gut microbiota on intestinal permeability: A novel strategy for treating gastrointestinal related diseases

Accumulating evidence emphasizes the critical reciprocity between gut microbiota and intestinal barrier function in maintaining the gastrointestinal homeostasis. Given the fundamental role caused by intestinal permeability, which has been scrutinized as a measurable potential indicator of perturbed barrier function in clinical researches, it seems not surprising that recent decades have been marked by augmented efforts to determine the interaction between intestinal microbes and permeability of the individual. However, despite the significant progress in characterizing intestinal permeability and the commensal bacteria in the intestine, the mechanisms involved are still far from being thoroughly revealed. In the present review, based on multiomic methods, high-throughput sequencing and molecular biology techniques, the impacts of gut microbiota on intestinal permeability as well as their complex interaction networks are systematically summarized. Furthermore, the diseases related to intestinal permeability and main causes of changes in intestinal permeability are briefly introduced. The purpose of this review is to provide a novel prospection to elucidate the correlation between intestinal microbiota and permeability, and to explore a promising solution for diagnosis and treatment of gastrointestinal related diseases.

National Survey of Feeding Tube Verification Practices: An Urgent Call for Auscultation Deimplementation

BACKGROUND

Harm events such as pneumothoraces and pneumonia continue to be associated with feeding tube insertion. Most bedside verification methods are not accurate to discriminate pulmonary from gastrointestinal system. Evidence-based clinical practice guidelines do not support auscultation of feeding tubes in adults, yet auscultation is the most common method used.

OBJECTIVES

Our survey assessed national feeding tube verification practices used by critical care nurses, including progress in auscultation method deimplementation, and stylet reinsertion and cleansing practices.

METHODS

A national survey of 408 critical care nurses was performed.

RESULTS

The majority performed auscultation (311 of 408 [76%]) to verify feeding tube placement. In the final multivariable model, nursing education, facility type, observation of colleagues performing auscultation, and awareness of an institutional policy were associated with auscultation of feeding tubes. Thirty-five percent used enteral access devices to verify initial feeding tube placement. Stylet cleansing methods were variable; 38% of reinserted stylets were not cleansed.

DISCUSSION

Minimal progress has been made in deimplementation of auscultation in the past 7 years despite passive knowledge dissemination in research articles, clinical practice guidelines, and procedure manuals. Although pH measure is used as a first-line feeding tube verification method in the United Kingdom, it is rarely used in the United States. Clinical practice guidelines should be updated to incorporate new research on enteral access systems.

CONCLUSIONS

Tradition-based practices such as auscultation and certain stylet cleansing methods should be deimplemented. A focused interdisciplinary, multifaceted program is needed to deimplement auscultation practice for adult feeding tubes.

ZnO Modulates Swine Gut Microbiota and Improves Growth Performance of Nursery Pigs When Combined with Peptide Cocktail

Zinc has been very efficacious in reducing post-weaning diarrhea, whereas animal-derived peptides are suggested to improve the growth performance of weaned piglets. However, the combined effect of zinc and peptides on swine production and swine gut microbiota is still largely unknown. In this study, we followed 288 nursery pigs from the age of d30 to d60 to evaluate the growth performance and gut microbiota of weanling pigs subjected to different levels of a fish-porcine-microbial peptide cocktail (0.05%, 0.25%, and 0.5%) with or without the pharmaceutical level of zinc oxide (ZnO) (2500 ppm) supplementation in a nutrient-deficient diet. Rectal swab samples were collected from pigs with body weight (BW) approach average at each pen on d30, d42, and d60 to determine gut microbiota. Average daily gain (ADG) and BW in piglets fed high zinc (HZ) increased with increasing levels of peptide. The microbiota of the HZ group also diverged from those of the standard zinc (SZ) group from d30 to d60. Adding peptide did not alter community structure regardless of zinc supplementation. Collectively, these findings demonstrated that the pharmaceutical level of zinc as ZnO conditioned the gut community to the point where peptide could effectively restore growth performance in nursery pigs fed nutrient-deficient diets.

Probiotic and synbiotic therapy in the critically ill: State of the art

Recent medical history has largely viewed our bacterial symbionts as pathogens to be eradicated rather than as essential partners in optimal health. However, one of the most exciting scientific advances in recent years has been the realization that commensal microorganisms (our microbiome) play vital roles in human physiology in nutrition, vitamin synthesis, drug metabolism, protection against infection, and recovery from illness. Recent data show that loss of "health-promoting" microbes and overgrowth of pathogenic bacteria (dysbiosis) in patients in the intensive care unit (ICU) appears to contribute to nosocomial infections, sepsis, and poor outcomes. Dysbiosis results from many factors, including ubiquitous antibiotic use and altered nutrition delivery in illness. Despite modern antibiotic therapy, infections and mortality from often multidrug-resistant organisms are increasing. This raises the question of whether restoration of a healthy microbiome via probiotics or synbiotics (probiotic and prebiotic combinations) to intervene on ubiquitous ICU dysbiosis would be an optimal intervention in critical illness to prevent infection and to improve recovery. This review will discuss recent innovative experimental data illuminating mechanistic pathways by which probiotics and synbiotics may provide clinical benefit. Furthermore, a review of recent clinical data demonstrating that probiotics and synbiotics can reduce complications in ICU and other populations will be undertaken. Overall, growing data for probiotic and symbiotic therapy reveal a need for definitive clinical trials of these therapies, as recently performed in healthy neonates. Future studies should target administration of probiotics and synbiotics with known mechanistic benefits to improve patient outcomes. Optimally, future probiotic and symbiotic studies will be conducted using microbiome signatures to characterize actual ICU dysbiosis and determine, and perhaps even personalize, ideal probiotic and symbiotic therapies.

Intestinal barrier integrity and function in infants with cholestasis

Background/Aims

The safety of the human body is maintained by effective monitoring of the mucosal surface integrity and protection against potentially harmful compounds. This function of the gut called intestinal barrier function can be affected by cholestasis and the absence of bile in the intestinal lumen. We aimed to determine whether the gut barrier integrity is impaired in infants with cholestasis by evaluation of the intestinal fatty acid binding proteins (I-FABP) and ileal bile acid binding protein (I-BABP) as markers of intestinal epithelial cell damage and plasma D-lactate level as a marker of gut wall permeability.

Methods

This case-control study included 53 infants with cholestasis and 29 controls. Serum levels of I-FABP, I-BABP, and D-lactate were measured in all subjects.

Results

Both groups of patients with neonatal hepatitis and biliary atresia showed significantly higher levels of I-FABP and I-BABP than the controls. There were no differences in the serum D-lactate level between the cases and controls. There was no difference between the two groups of patients (I and II) regarding any of the parameters studied. No significant correlations between serum levels of I-FABP, I-BABP, or D-lactate and total or direct bilirubin levels were found in the cholestatic infants.

Conclusions

The intestinal epithelial barrier integrity is breached nearly in all parts of the intestine in infants with cholestasis. Further research is recommended to determine the impact of this finding on the management of these infants. The relationship between physical intestinal barrier damage and its functional failure remains subject for further research.

The Microbiome, Intestinal Function, and Arginine Metabolism of Healthy Indian Women Are Different from Those of American and Jamaican Women

BACKGROUND

Indian women have slower arginine flux during pregnancy compared with American and Jamaican women. Arginine is a semi-essential amino acid that becomes essential during periods of rapid lean tissue deposition. It is synthesized only from citrulline, a nondietary amino acid produced mainly in the gut. The gut is therefore a key site of arginine and citrulline metabolism, and gut microbiota may affect their metabolism.

OBJECTIVE

The objective of this study was to identify differences in the gut microbiota of nonpregnant American, Indian, and Jamaican women and characterize the relations between the gut microbiota, gut function, and citrulline and arginine metabolism.

METHODS

Thirty healthy American, Indian, and Jamaican women (n = 10/group), aged 28.3 ± 0.8 y, were infused intravenously with [guanidino-15N2]arginine, [5,5-2H2]citrulline, and [15N2]ornithine and given oral [U-13C6]arginine in the fasting and postprandial states. Fecal bacterial communities were characterized by 16S rRNA gene sequencing.

RESULTS

In the fasting state, Indian women had lower citrulline flux than did American and Jamaican women [7.0 ± 0.4 compared with 9.1 ± 0.4 and 8.9 ± 0.2 μmol ⋅ kg fat-free mass (FFM)-1 ⋅ h-1, P = 0.01] and greater enteral arginine conversion to ornithine than did American women (1.4 ± 0.11 compared with 1.0 ± 0.08 μmol ⋅ kg FFM-1 ⋅ h-1, P = 0.04). They also had lower mannitol excretion than American and Jamaican women (154 ± 37.1 compared with 372 ± 51.8 and 410 ± 39.6 mg/6 h, P < 0.01). Three dominant stool community types characterized by increased abundances of the genera Prevotella, Bacteroides, and Bacteroides with Clostridium were identified. Indian women had increased mean relative abundances of Prevotella (42%) compared to American and Jamaican women (7% and < 1%, P = 0.03) which were associated with diet, impaired intestinal absorptive capacity, and arginine flux.

CONCLUSIONS

These findings suggest that dysregulated intestinal function and a unique gut microbiome may contribute to altered arginine metabolism in Indian women.

Small intestinal permeability in older adults

It is not yet clear whether intestinal mucosal permeability changes with advancing age in humans. This question is of high importance for drug and nutrition approaches for older adults. Our main objective was to answer the question if small intestinal barrier integrity deteriorates with healthy aging. We conducted a cross‐sectional study including the pooled data of 215 nonsmoking healthy adults (93 female/122 male), 84 of whom were aged between 60 and 82 years. After a 12‐h fast, all participants ingested 10 g of lactulose and 5 g of mannitol. Urine was collected for 5 h afterwards and analyzed for test sugars. The permeability index (PI = lactulose/mannitol) was used to assess small intestinal permeability. Low‐grade inflammation defined by high‐sensitivity C‐reactive protein ≥1 mL/L and kidney function (estimated glomerular filtration rate) were determined in the older age group. The PI was similar in older compared to younger adults (P =0.887). However, the urinary recovery of lactulose and mannitol was lower in the older adults and this change was neither associated with urinary volume nor glomerular filtration rate. The PI was not significantly correlated with low‐grade inflammation or presence of noninsulin‐dependent type 2 diabetes. However, it significantly deteriorated in the copresence of both conditions compared to low‐grade inflammation alone (P =0.043) or type 2 diabetes alone (P =0.015). Small intestinal mucosal barrier does not deteriorate with age per se. But low‐grade inflammation coupled with minor disease challenges, such as type 2 diabetes, can compromise the small intestinal barrier.

Until now, it has not been clear if the small intestinal mucosal barrier deteriorates with age per se. We investigated the pooled data of 215 nonsmoking healthy adults, 84 of whom were aged between 60 and 82 years and found similar intestinal permeability results in all age classes. However, in participants with low‐grade inflammation coupled with type 2 diabetes the small intestinal integrity was compromised.

Intestinal CYP3A4 protects against lithocholic acid-induced hepatotoxicity in intestine-specific VDR-deficient mice

Vitamin D receptor (VDR) mediates vitamin D signaling involved in bone metabolism, cellular growth and differentiation, cardiovascular function, and bile acid regulation. Mice with an intestine-specific disruption of VDR (Vdr(ΔIEpC)) have abnormal body size, colon structure, and imbalance of bile acid metabolism. Lithocholic acid (LCA), a secondary bile acid that activates VDR, is among the most toxic of the bile acids that when overaccumulated in the liver causes hepatotoxicity. Because cytochrome P450 3A4 (CYP3A4) is a target gene of VDR-involved bile acid metabolism, the role of CYP3A4 in VDR biology and bile acid metabolism was investigated. The CYP3A4 gene was inserted into Vdr(ΔIEpC) mice to produce the Vdr(ΔIEpC)/3A4 line. LCA was administered to control, transgenic-CYP3A4, Vdr(ΔIEpC), and Vdr(ΔIEpC)/3A4 mice, and hepatic toxicity and bile acid levels in the liver, intestine, bile, and urine were measured. VDR deficiency in the intestine of the Vdr(ΔIEpC) mice exacerbates LCA-induced hepatotoxicity manifested by increased necrosis and inflammation, due in part to over-accumulation of hepatic bile acids including taurocholic acid and taurodeoxycholic acid. Intestinal expression of CYP3A4 in the Vdr(ΔIEpC)/3A4 mouse line reduces LCA-induced hepatotoxicity through elevation of LCA metabolism and detoxification, and suppression of bile acid transporter expression in the small intestine. This study reveals that intestinal CYP3A4 protects against LCA hepatotoxicity.

Eicosapentaenoic acid enhances heat stress-impaired intestinal epithelial barrier function in Caco-2 cells

Objective

Dysfunction of the intestinal epithelial tight junction (TJ) barrier is known to have an important etiologic role in the pathophysiology of heat stroke. N-3 polyunsaturated fatty acids (PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play a role in maintaining and protecting the TJ structure and function. This study is aimed at investigating whether n-3 PUFAs could alleviate heat stress-induced dysfunction of intestinal tight junction.

Methods

Human intestinal epithelial Caco-2 cells were pre-incubated with EPA, DHA or arachidonic acid (AA) and then exposed to heat stress. Transepithelial electrical resistance (TEER) and Horseradish Peroxidase (HRP) permeability were measured to analyze barrier integrity. Levels of TJ proteins, including occludin, ZO-1 and claudin-2, were analyzed by Western blot and localized by immunofluorescence microscopy. Messenger RNA levels were determined by quantitative real time polymerase chain reaction (Q-PCR). TJ morphology was observed by transmission electron microscopy.

Results

EPA effectively attenuated the decrease in TEER and impairment of intestinal permeability in HRP flux induced by heat exposure. EPA significantly elevated the expression of occludin and ZO-1, while DHA was less effective and AA was not at all effective. The distortion and redistribution of TJ proteins, and disruption of morphology were also effectively prevented by pretreatment with EPA.

Conclusion

This study indicates for the first time that EPA is more potent than DHA in protecting against heat-induced permeability dysfunction and epithelial barrier damage of tight junction.

Arginyl-glutamine dipeptide or docosahexaenoic acid attenuates hyperoxia-induced small intestinal injury in neonatal mice

BACKGROUND AND OBJECTIVE

Supplementation studies of glutamine, arginine, and docosahexaenoic acid (DHA) have established the safety of each of these nutrients in neonates; however, the potential for a more stable and soluble dipeptide, arginyl-glutamine (Arg-Gln) or DHA with anti-inflammatory properties, to exert benefits on hyperoxia-induced intestinal injury has not been investigated. Arg-Gln dipeptide has been shown to prevent retinal damage in a rodent model of oxygen-induced injury. The objective of the present study was to investigate whether Arg-Gln dipeptide or DHA could also attenuate markers of injury and inflammation to the small intestine in this same model.

METHODS

Seven-day-old mouse pups were placed with their dams in 75% oxygen for 5 days. After 5 days of hyperoxic exposure (P7-P12), pups were removed from hyperoxia and allowed to recover in atmospheric conditions for 5 days (P12-P17). Mouse pups received Arg-Gln (5g·kg·day) or DHA (5g·kg·day) or vehicle orally started on P12 through P17. Distal small intestine (DSI) histologic changes, myeloperoxidase (MPO), lactate dehydrogenase (LDH), inflammatory cytokines, and tissue apoptosis were evaluated.

RESULTS

Hyperoxic mice showed a greater distortion of overall villus structure and with higher injury score (P<0.05). Arg-Gln dipeptide and DHA supplementation groups were more similar to the room air control group. Supplementation of Arg-Gln or DHA reduced hyperoxia-induced MPO activity (P<0.05). Supplementation of Arg-Gln or DHA returned LDH activity to the levels of control. Hyperoxia induced apoptotic cell death in DSIs, and both Arg-Gln and DHA reversed this effect (P<0.05).

CONCLUSIONS

Supplementation with either Arg-Gln or DHA may limit some inflammatory and apoptotic processes involved in hyperoxic-induced intestinal injury in neonatal mice.

[Abdominal compartment syndrome and acute intestinal distress syndrome]

Seriously ill patients frequently present intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) as complications, and the associated mortality is very high. This review offers an update on the most controversial aspects of these entities: factors favoring their appearance, the most common causes, prognosis, and methods of measuring intra-abdominal pressure (IAP), physiopathological consequences in relation to the different organs and systems, and the currently accepted treatment measures (medical and/or surgical). Simultaneously to the strictly physical mechanisms of injury, such as direct compression of intra-abdominal organs and vessels, the transmission of IAP to other compartments, and the drop in cardiac output, a series of immune-inflammatory mediators generated in the intestine itself may also intervene. Hypoperfusion, sustained ischemia and the ischemia-reperfusion phenomenon, would act upon the microbiota, intestinal epithelium and intestinal immune system, triggering a systemic inflammatory response and multiorgan dysfunction that appears in the final stages of ACS.

In vivo effects of dietary (1→3), (1→4)-β-D-glucans from oat on mucosal immune responses in man and mice

OBJECTIVE

Antimicrobial peptides and tight junction proteins are crucial to maintain mucosal immunity. It is known that oat β-glucan may affect intestinal immunity. Therefore, the aim of the present study was to evaluate the effect of oat β-glucan on the presence of antimicrobial peptides and tight junction protein.

MATERIAL AND METHODS

We analyzed antimicrobial peptide levels in fecal water prepared from 24 h ileostomic bag contents obtained from ileostomic patients consuming oat β-glucan enriched or control diets in a cross-over design. In addition, intestinal sections of mice, which received oat β-glucan via oral gavages for 3.5 days, were analyzed for lysozyme and zonula occludens-1 expression.

RESULTS

We observed a trend toward lower lysozyme (-23%; p = 0.076) and bactericidal/permeability-increasing protein (-17%; p = 0.098) levels in oat β-glucan enriched fecal water as compared with placebo. Additionally, mice receiving oat β-glucan showed a lower lysozyme expression in stained distal small intestinal sections (p = 0.011). Staining of zonula occludens-1 was decreased in β-glucan treated mice indicating disruption of the tight junction integrity.

CONCLUSIONS

In conclusion, the consumption of oat β-glucan seems to decrease the levels of antimicrobial peptides in fecal water from human ileostomy patients and its expression in distal small intestine sections in mice. The decreased intestinal integrity in mice could be explained by the drop in antimicrobial peptides.

Novel model of peripheral tissue trauma-induced inflammation and gastrointestinal dysmotility

BACKGROUND

Trauma is a leading cause of death and although the gut is recognized as the 'motor' of post-traumatic systemic inflammatory response syndrome and multiple organ failure, studies on the gastrointestinal (GI) tract are few. Our objectives were to create a precisely controllable tissue injury model in which GI motility, systemic inflammation and wound fluid can be analyzed.

METHODS

A non-narcotic murine trauma model was developed by the subcutaneous dorsal trans-implantation of a devitalized donor syngeneic harvested tissue-bone matrix (TBX), which was precisely adjusted to % total body weight and studied after 21 h. Gastrointestinal transit histograms were plotted after the oral administration of non-digestible FITC-dextran and geometric centers calculated. Organ bath evaluated jejunal circular muscle contractility. Multiplex electrochemiluminescence measurements of serum and TBX wound fluid inflammatory mediators were performed.

KEY RESULTS

Increasing TBX amounts progressively delayed transit, whereas TBX heat denaturation or decellularization prevented ileus and death. In the TBX(17.5%) model, jejunal muscle contractility was suppressed and a systemic inflammatory response developed as significant serum elevations in IL-6, keratinocyte cytokine and IL-10 compared to sham. In addition, inflammatory responses within the wound fluid showed elevated levels of preformed IL-1β and TNF-α, whereas, 21 h after implantation IL-1β, IL-6 and keratinocyte cytokine were significantly increased in the wound.

CONCLUSIONS & INFERENCES

A novel donor tissue-bone matrix trauma model was developed that is precisely adjustable and recapitulates important clinical phenomena. The non-narcotic model demonstrated that increasing tissue injury progressively caused ileus, initiated a systemic inflammatory response and developed inflammatory changes within the wound.

Glutamate reduces experimental intestinal hyperpermeability and facilitates glutamine support of gut integrity

AIM: To assess whether glutamate plays a similar role to glutamine in preserving gut wall integrity.

METHODS: The effects of glutamine and glutamate on induced hyperpermeability in intestinal cell lines were studied. Paracellular hyperpermeability was induced in Caco2.BBE and HT-29CL.19A cell lines by adding phorbol-12,13-dibutyrate (PDB) apically, after which the effects of glutamine and glutamate on horseradish peroxidase (HRP) diffusion were studied. An inhibitor of glutamate transport (L-trans-pyrrolidine-2,4-dicarboxylic acid: trans-PDC) and an irreversible blocker (acivicin) of the extracellular glutamine to glutamate converting enzyme, γ-glutamyltransferase, were used.

RESULTS: Apical to basolateral HRP flux increased significantly compared to controls not exposed to PDB (n = 30, P < 0.001). Glutamine application reduced hyperpermeability by 19% and 39% in the respective cell lines. Glutamate application reduced hyperpermeability by 30% and 20%, respectively. Incubation of HT29CL.19A cells with acivicin and subsequent PDB and glutamine addition increased permeability levels. Incubation of Caco2.BBE cells with trans-PDC followed by PDB and glutamate addition also resulted in high permeability levels.

CONCLUSION: Apical glutamate -similar to glutamine- can decrease induced paracellular hyperpermeability. Extracellular conversion of glutamine to glutamate and subsequent uptake of glutamate could be a pivotal step in the mechanism underlying the protective effect of glutamine.

Non-invasive markers of gut wall integrity in health and disease

The intestinal mucosa is responsible for the absorption of nutrients from the lumen and for the separation of the potentially toxic luminal content (external environment) from the host (internal environment). Disruption of this delicate balance at the mucosal interface is the basis for numerous (intestinal) diseases. Experimental animal studies have shown that gut wall integrity loss is involved in the development of various inflammatory syndromes, including post-operative or post-traumatic systemic inflammatory response syndrome, sepsis, and multiple organ failure. Assessment of gut wall integrity in clinical practice is still a challenge, as it is difficult to evaluate the condition of the gut non-invasively with currently available diagnostic tools. Moreover, non-invasive, rapid diagnostic means to assess intestinal condition are needed to evaluate the effects of treatment of intestinal disorders. This review provides a survey of non-invasive tests and newly identified markers that can be used to assess gut wall integrity.

Non-invasive markers of gut wall integrity in health and disease

The intestinal mucosa is responsible for the absorption of nutrients from the lumen and for the separation of the potentially toxic luminal content (external environment) from the host (internal environment). Disruption of this delicate balance at the mucosal interface is the basis for numerous (intestinal) diseases. Experimental animal studies have shown that gut wall integrity loss is involved in the development of various inflammatory syndromes, including post-operative or post-traumatic systemic inflammatory response syndrome, sepsis, and multiple organ failure. Assessment of gut wall integrity in clinical practice is still a challenge, as it is difficult to evaluate the condition of the gut non-invasively with currently available diagnostic tools. Moreover, non-invasive, rapid diagnostic means to assess intestinal condition are needed to evaluate the effects of treatment of intestinal disorders. This review provides a survey of non-invasive tests and newly identified markers that can be used to assess gut wall integrity.

Rapid development of intestinal cell damage following severe trauma: a prospective observational cohort study

Introduction

Loss of intestinal integrity has been implicated as an important contributor to the development of excessive inflammation following severe trauma. Thus far, clinical data concerning the occurrence and significance of intestinal damage after trauma remain scarce. This study investigates whether early intestinal epithelial cell damage occurs in trauma patients and, if present, whether such cell injury is related to shock, injury severity and the subsequent inflammatory response.

Methods

Prospective observational cohort study in 96 adult trauma patients. Upon arrival at the emergency room (ER) plasma levels of intestinal fatty acid binding protein (i-FABP), a specific marker for damage of differentiated enterocytes, were measured. Factors that potentially influence the development of intestinal cell damage after trauma were determined, including the presence of shock and the extent of abdominal trauma and general injury severity. Furthermore, early plasma levels of i-FABP were related to inflammatory markers interleukin-6 (IL-6), procalcitonin (PCT) and C-reactive protein (CRP).

Results

Upon arrival at the ER, plasma i-FABP levels were increased compared with healthy volunteers, especially in the presence of shock (P < 0.01). The elevation of i-FABP was related to the extent of abdominal trauma as well as general injury severity (P < 0.05). Circulatory i-FABP concentrations at ER correlated positively with IL-6 and PCT levels at the first day (r² = 0.19; P < 0.01 and r² = 0.36; P < 0.001 respectively) and CRP concentrations at the second day after trauma (r² = 0.25; P < 0.01).

Conclusions

This study reveals early presence of intestinal epithelial cell damage in trauma patients. The extent of intestinal damage is associated with the presence of shock and injury severity. Early intestinal damage precedes and is related to the subsequent developing inflammatory response.

Glutamine deprivation alters intestinal tight junctions via a PI3-K/Akt mediated pathway in Caco-2 cells

Glutamine (Gln) is important for intestinal barrier function and regulation of tight junction (TJ) proteins, but the intracellular mechanisms of action remain undefined. The purpose of this study was to test the hypothesis that Gln regulates intercellular junction integrity and TJ proteins through the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in Caco-2 cells. Deprivation of exogenous and endogenous glutamine decreased transepithelial electrical resistance (TER) (P < 0.01) and increased permeability (P < 0.01). Both wortmannin and LY294002, PI3K inhibitors, prevented the TER decrease and the permeability increase induced by Gln deprivation (P < 0.001). Gln deprivation also caused decreased TJ protein claudin-1 (P < 0.001). Both wortmannin and LY294002 treatment prevented this effect (P < 0.001). Deprivation of Gln increased phosphor-Akt protein. Gln supplementation reversed this effect. Decreased TER and increased permeability associated with Gln deprivation were not observed in small interfering RNA for p85 transfected Caco-2 cells. In conclusion, Gln regulates intercellular junction integrity and TJ proteins through the PI3-Kinase/Akt pathway.

Development of hypertriglyceridemia in patients with enterocutaneous fistulas

BACKGROUND & AIMS

Hypertriglyceridemia is commonly observed in patients with enterocutaneous fistulas, compromising their health status. In this study potential causes for hypertriglyceridemia in patients with an enterocutaneous fistula are explored and treatment options discussed accordingly.

METHODS

A database was created consisting of all consecutively treated patients with an enterocutaneous fistula from 1991 until 2007. Two successive measures of serum triglyceride concentrations of more than 3.0 mmol/L (266 mg/dL) were regarded as hypertriglyceridemia. The relation between fistula specific characteristics and hypertriglyceridemia was analyzed using a multivariable Cox proportional hazard model with time-dependent covariates.

RESULTS

A total 102 patients were eligible for this study of whom 25 had hypertriglyceridemia. Multivariable analysis showed that sepsis (HR 4.503, CI 1.778-11.401, P=0.002), high output small bowel fistula (HR 3.534, CI 1.260-9.916, P=0.016), parenteral nutrition (HR 5.689, CI 1.234-26.216, P=0.026) and inflammatory diseases (inflammatory bowel disease vs. malignancy HR 6.211, CI 1.081-35.696, P=0.041) were independent predictors of hypertriglyceridemia.

CONCLUSIONS

High triglyceride concentrations in patients with an enterocutaneous fistula were mainly associated with sepsis, a high output small bowel fistula, nutrition by the parenteral route and primary diseases with inflammatory aetiology. This should direct a treatment strategy that focuses on these aspects.