Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Intestinal barrier”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed1998

Increased gut permeability after hemorrhage is associated with upregulation of local and systemic IL-6.

Although intestinal barrier failure after hemorrhage is a well-documented event, the underlying mechanism is poorly understood. The aim of this study, therefore, was to determine whether altered intestinal permeability after hemorrhage is associated with upregulation of local and systemic interleukin-6 (IL-6). To study this, rats underwent laparotomy (i.e., trauma induced) and were bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of the shed blood volume was returned in the form of Ringer's lactate. The animals were then resuscitated with four times the volume of shed blood with Ringer's lactate over 60 min. At 1.5 h postresuscitation, an in vivo ligated loop of a distal small intestine was formed and the passage of 4-kDa fluorescein isothiocyanate-conjugated dextran (FD4) from the intestinal lumen into the portal vein and carotid artery blood was analyzed by fluorescence spectrometry. Samples from the portal vein and a carotid artery were collected and plasma IL-6 was assayed. Intraepithelial lymphocytes from a distal small intestine were isolated and cultured in vitro for 24 h with or without anti-rat CD3 monoclonal antibody stimulation. IL-6 activity in freshly isolated cells and its release by cultured lymphocytes were determined. Intestinal perfusion and portal blood flow were determined by radioactive microspheres in another set of parallel experiments. The results indicate that lumen-to-blood passage of FD4 through the wall of the small intestine increased significantly at 1.5 h after hemorrhage and resuscitation and was associated with decreased intestinal perfusion and portal blood flow. Plasma IL-6 levels in the portal vein and carotid artery markedly increased at 1.5 h after hemorrhage and resuscitation. In addition, a significant correlation was observed between plasma IL-6 and FD4 concentrations. Higher IL-6 activity in freshly isolated cells was found in hemorrhaged rats. Increased IL-6 release by cultured lymphocytes was also observed either with or without anti-rat CD3 monoclonal antibody stimulation. Thus, the increased intestinal permeability following trauma-hemorrhage and resuscitation appears to be associated with systemic and intestinal IL-6 upregulation.

Animals↗
PubMed1998

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.

Adult↗
PubMed2004

A potential role of hyperbaric oxygen exposure through intestinal nuclear factor-kappaB.

OBJECTIVE: Recent studies have demonstrated the therapeutic effectiveness and pharmacologic mechanisms of hyperbaric oxygen therapy (HBOT) in the treatment of a systemic shock state. To elucidate the in vivo role of HBOT during sepsis, we evaluated the effects of HBOT on intestinal mucosal injury and bacterial translocation after lipopolysaccharide challenge. DESIGN: Experimental study. SETTING: First Department of Surgery and Division of Emergency Care, Kagoshima University School of Medicine, Kagoshima, Japan. SUBJECTS: : Male rats were treated with lipopolysaccharide by an intraperitoneal route or with lipopolysaccharide and HBOT. INTERVENTIONS: The survival rate, small intestinal tissue damage, and bacterial translocation in the HBOT-treated group were compared with those in the untreated group. Moreover, plasma tumor necrosis factor-alpha and nitrite/nitrate concentrations, inducible nitric oxide synthase and myeloperoxidase activities, and nuclear factor-kappaB in ileal mucosa were investigated. HBOT was initiated 3 hrs after lipopolysaccharide challenge and administered as 100% oxygen, at 2.53 x 10 kPa (2.5 atm absolute), for 60 mins. MEASUREMENTS AND MAIN RESULTS: When a sublethal dose of lipopolysaccharide (24 mg/kg) was given, the survival rate was much better in the HBOT-treated group (75%) than in the untreated group (33%). HBOT given 3 hrs after lipopolysaccharide injection (10 mg/kg) also lessened the histologic tissue damage of the terminal ileum and the incidence and magnitude of bacterial translocation to mesenteric lymph nodes at 24 hrs after the lipopolysaccharide injection. Moreover, HBOT was able to reduce mucosal inducible nitric oxide synthase and myeloperoxidase activities and plasma nitrite/nitrate concentrations but not serum tumor necrosis factor-alpha concentrations. Immunohistochemical examination revealed that HBOT specifically modified the mucosal nuclear factor-kappaB activation within 4-6 hrs after the injection. CONCLUSIONS: HBOT performed 3 hrs after lipopolysaccharide challenge alleviates intestinal barrier dysfunction and improves survival rates. Herein, we propose one possible mechanism for these beneficial effects: HBOT can modify the nuclear factor-kappaB activation in the intestinal mucosa and attenuate the sequential nitric oxide overproduction and myeloperoxidase activation. Consequently, bacterial translocation could be potentially decreased. We believe that the present study should lead to an improved understanding of HBOT's potential role in sepsis.

Animals↗
PubMed2002

Experimental models of small intestinal transplantation in rats: orthotopic versus heterotopic model.

Two kinds of surgical models of small intestinal transplantation (SITx) in rats, namely heterotopic (HIT) and orthotopic transplantion (OIT), have been reviewed. In OIT, the small intestine of the recipient is removed and the transplanted intestine replaces it in continuity. On the other hand, in the HIT model, the small intestinal grafts are rendered dysfunctional without alimentary tract continuity. Histological evidence showed that acute rejection appeared earlier in HIT as compared to OIT. Hyperplasia and hypertrophy of the muscularis externa produced in the chronic rejection process were more pronounced in HIT allografts. The HIT grafts showed severe mucosal atrophy due to the lack of intraluminal trophic factors, because oral feedings can stimulate tropic hormones for mucosal growth, and provide nutrients for enterocytes. Intestinal permeability was consistently higher after HIT than after OIT. The HIT grafts demonstrated less contractility and less response to chemical stimulation than did OIT grafts. The OIT models are advantageous in studies of intraluminal nutrients, and intestinal secretions in these models might modulate the intestinal immune status and possibly delay rejection. The superior intestinal barrier function and the delayed onset of rejection in OIT rats suggest that nutrients and other factors in the succus entericus are important for the maintenance of intestinal graft function.

Animals↗
PubMed1999

[Excretion ratio of lactulose and mannitol as intestinal permeability index in healthy Chinese volunteers].

OBJECTIVE: To determine lactulose (L)/mannitol (M) excretion ratio with high pressure liquid chromatograph with pulsed electrochemical detection (HPLC-PED) in healthy Chinese volunteers. METHODS: Sixty healthy Chinese volunteers enrolled. For each volunteer the L/M permeability study was performed twice by two different doses, as small dose (1 g mannitol and 2 g lactulose) and regular dose (5 g mannitol and 10 g lactulose). The urine were collected during 6 hours after ingestion of the test solution. The M and L concentrations were analyzed by HPLC with pulsed electrochemical detection. RESULTS: The L/M ratio was 0.026 +/- 0.006 in the small doses tests, and 0.036 +/- 0.008 in the large doses tests. CONCLUSIONS: With HPLC-PED detection, a low doses of lactulose and mannitol can be used to study intestinal permeability. Determination of the L/M ratio may be a way of evaluating intestinal barrier function in clinical practice.

Adult↗
PubMed2002

Immunological effects of yogurt addition to a re-nutrition diet in a malnutrition experimental model.

The therapeutic and preventive effects of yogurt and lactic acid bacteria on diseases such as cancer, infection and gastrointestinal disorders are well ocumented. The aim of this research was to study the effects of different doses of yogurt addition after milk re-nutrition diet, on the recovery of the intestinal barrier and mucosal immune function. Experiments were performed on groups of mice, malnourished and re-nourished with milk during 7 d, and mice with diet supplemented with yogurt for 2, 5 and 7 consecutive d. Nutritional parameters such as weight gain, serum total protein, and the number of IgA, IgM and IgG B cells of the small intestine were determined. We also quantified intraepithelial leukocytes, mastocytes and goblet cells, and performed structural and ultrastructural studies on the small intestine. We observed that 5 d of yogurt feeding was the optimal dose for improving gut barrier function and mucosal immune system in a malnutrition model. This effect was not observed with milk re-nutrition. Although the results were better for 5 d of yogurt, addition for 7 d also showed beneficial effects. Yogurt feeding in our model did not impair any gut functions. These results suggest that yogurt addition after a re-nutrition diet gives better recovery of intestinal function than the re-nutrition diet usually recommended. Although these results were obtained in an animal model, they indicate that consumption of yogurt by malnourished children might accelerate the restoration of gut function.

Animals↗
PubMed2004

Intestinal epithelial defense systems protect against bacterial threats.

Numerous bacterial species inhabit the lumen of the human intestine. The epithelial cells that line the intestinal barrier are in direct contact with many of these species and have developed sophisticated strategies to prevent bacterial invasion of host tissue beyond simply providing a physical blockade. Intestinal epithelial cells (IECs) possess receptors that are capable of recognizing bacterial products, and engagement of these receptors results in the production and secretion of immunoregulatory proteins, such as cytokines and chemokines, which mobilize immune effector cells, including macrophages, dendritic cells, and neutrophils. In addition, IECs can produce various lipid-based eicosanoids that can contribute to the orchestration of the immune response. A better understanding of how the intestinal epithelium interacts with its microbial constituents may provide insight into strategies for treatment of enteric infections and inflammatory bowel disease.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Experimental obstructive jaundice alters claudin-4 expression in intestinal mucosa: effect of bombesin and neurotensin.

AIM: To investigate the influence of experimental obstructive jaundice and exogenous bombesin (BBS) and neurotensin (NT) administration on the expression of the tight junction (TJ)-protein claudin-4 in intestinal epithelium of rats. METHODS: Forty male Wistar rats were randomly divided into five groups: I = controls, II = sham operated, III = bile duct ligation (BDL), IV = BDL+BBS (30 microg/kg per d), V = BDL+NT (300 microg/kg per d). At the end of the experiment on d 10, endotoxin was measured in portal and aortic blood. Tissue sections of the terminal ileum were examined histologically and immunohistochemically for evaluation of claudin-4 expression in intestinal epithelium. RESULTS: Obstructive jaundice led to intestinal barrier failure demonstrated by significant portal and aortic endotoxemia. Claudin-4 expression was significantly increased in the upper third of the villi in jaundiced rats and an upregulation of its lateral distribution was noted. Administration of BBS or NT restored claudin-4 expression to the control state and significantly reduced portal and aortic endotoxemia. CONCLUSION: Experimental obstructive jaundice increases claudin-4 expression in intestinal epithelium, which may be a key factor contributing to the disruption of the mucosal barrier. Gut regulatory peptides BBS and NT can prevent this alteration and reduce portal and systemic endotoxemia.

Animals↗
PubMed2000

Intestinal microvascular patterns during hemorrhagic shock.

While injuries due to a hypoxic state commonly appear later in both intestinal crypts and basal portion of the villi than in the apical portion, a nonhomogeneous distribution of blood flow in the intestinal mucosa may be supposed. The presence of two different microvascular plexuses inside the mucosa, corresponding to the cryptal plexus and the villous plexus, supports the above hypothesis. This work studies the intestinal microvasculature in shocked versus normal rats. Forty-five rats were divided into four groups to study the histological damage and the microvascular bed by ink injection, fluorescent microsphere infusion, and resin injection for scanning electron microscopy (SEM) of vascular corrosion cast (VCC) observations. An infusion pressure of 100 +/- 5 mm Hg was used in control animals, while 30 +/- 5 mm Hg infusion pressure was adopted for controls as well as for shocked animals to simulate physiological or shock conditions. Hemorrhagic shock was induced by removing blood and maintaining a mean arterial pressure of 30 +/- 5 mm Hg for 45-120 mins. A close connection among the patterns of microvasculature obtained with VCC and ink injection technique can be appreciated. In normal rats the whole microvasculature was visualized, but in both normal and shocked animals injected at low pressure different patterns could be found, generally showing a highly incomplete visualization of the vascular network. A significant decrease of visualization of both the entire microvasculature and the villous plexus is present in shocked animals when compared to unshocked controls, while no difference in the cryptal plexus visualization was observed. These observations suggest that the cryptal plexus is perfused preferentially during hemorrhagic shock, as a consequence of its peculiar microvascular organization. This may explain the relative resistance of the crypts, compared to villi, to hypoxic injuries in order to sustain endocrine function and the regenerative capability of the mucosa after prolonged hypoperfusion conditions that can lead to villous damage and temporary loss of the intestinal barrier function.

Animals↗
PubMed1998

Permeability characteristics of piperine on oral absorption--an active alkaloid from peppers and a bioavailability enhancer.

Piperine, [1-[5-[1,3-benzodioxol-5-yl]-1-oxo-2,4, pentadienyl] piperidine], is a pungent alkaloid present in Piper nigrum Linn, and P. longum Linn. It is shown to enhance the bioavailability of various structurally and therapeutically diverse drugs. A concise mechanism responsible for its bioavailability enhancing action is poorly understood. This study is an effort to understand the absorption dynamics of piperine in intestine on oral absorption. It encompasses intestinal everted sacs as an experimental model. Cycloheximide treatment and exclusion of Na+ salts from incubating medium were the variables used. Absorption half life, absorption rate, absorption clearance and apparent permeability co-efficient were computed from the data. Experiments to denote physico-chemical characteristics of this moiety exhibited that it is a weak base, highly lipophilic in nature with partial solubility in aqueous media. It exhibited passive diffusion constituting non-saturable absorption kinetics. Transport of piperine was not resisted by UWL and was proposed to be absorbed through transcellular pathway. It displayed short absorption clearance and high apparent permeability co-efficient. Data thus obtained suggested that piperine is absorbed very fast across the intestinal barrier. It may act as an apolar molecule and form apolar complex with drugs and solutes. It may modulate membrane dynamics due to its easy partitioning thus helping in efficient permeability across the barriers.

Absorption↗
PubMed2006

[Intestinal permeability and cirrhosis].

Patients with cirrhosis are at increased risk of developing infections due to bacterial translocation. This process depends on three principal factors: bacterial overgrowth, immunodepression, and altered intestinal permeability. Intestinal barrier functions may be disturbed in cirrhosis, related to the toxic effects of alcohol (on mucosa and biological membranes) and portal hypertensive enteropathy. Few studies on the assessment of intestinal permeability in cirrhotic patients are available, and contradictory results may be explained by methodological differences. However, four studies using a differential sugar absorption test (lactulose-mannitol test, a combination of an oligosaccharide and a monosaccharide) showed an increased intestinal permeability in cirrhotic patients. The recurrence of spontaneous bacterial peritonitis can be appreciated only by one similar case history, a low rate of protides in ascites (<10 g/L), bilirubinemia > 55 micromol/L, and thrombocytopenia<98.000/mm3. These results suggest that primary antibiotherapy prophylaxis should be recommended, but this recommendation is limited by the risk of bacterial resistant selection and by the fact that no patient survival benefits was shown. Intestinal permeability could be another predictive factor to justify preventive antibiotherapy; but more studies are needed and methods should be standardized (technique used to measure permeability, patient groups involved).

Humans↗
PubMed1994

Increased intestinal marker absorption due to regional permeability changes and decreased intestinal transit during sepsis in the rat.

BACKGROUND: The intestinal barrier properties are impaired during inflammation and sepsis, but the mechanisms behind this are unknown and were therefore investigated during experimental sepsis in rats. METHODS: The different-sized intestinal absorption markers 51Cr-labeled ethylenediaminetetraacetic acid (EDTA) and ovalbumin were gavaged to rats made septic by intra-abdominal bacterial implantation and to sham-operated rats. Regional tissue permeability was measured in diffusion chambers, and intestinal transit was evaluated by intestinal accumulation of gavaged 51Cr-EDTA. RESULTS: In comparison with the sham-operated rats, septic rats had higher 51Cr-EDTA levels in blood and urine and showed a prolonged intestinal transit. Septic rats also had a lower tissue permeability to both markers in the small intestines but higher permeability to ovalbumin in the colon. Rats receiving morphine to decrease intestinal motility showed similar changes, with a decreased intestinal transit and increased marker absorption. CONCLUSIONS: The results suggest that the increased intestinal absorption during sepsis was due to regional permeability changes and prolonged intestinal transit.

Animals↗
PubMed1997

Effect of enteral glutamine on intestinal permeability and bacterial translocation after abdominal radiation injury in rats.

We investigated the effect of enteral glutamine on intestinal permeability and bacterial translocation after whole abdominal radiation in rats. Rats irradiated with 10 Gy to the abdomen were randomly divided into a glutamine-free diet group and a glutamine-rich diet (2% glutamine) group. After 3 days of feeding of each diet, the 6-h urinary recovery of polyethylene glycol 4000 was significantly decreased in the glutamine-rich diet group compared to that in the glutamine-free diet group. The 6-h urinary recovery of phenolsulfonphthalein was also decreased in the glutamine-rich diet group, but the difference was not significant. Plasma endotoxin concentration was significantly lower in the glutamine-rich diet group. Twenty-four hour after gavage with 14C-labeled Escherichia coli, the detection rate of 14C-labeled bacteria in the mesenteric lymph nodes of rats was significantly lower in the glutamine-rich diet group. The adherence of 14C-labeled E. coli in the jejunal mucosa was significantly lower in the glutamine-rich diet group than in the glutamine-free diet group, but there were no significant differences in the ileal mucosa. These findings suggest that in rats with intestinal injury induced by irradiation, enteral glutamine maintains the intestinal barrier and reduces bacterial translocation.

Animals↗
PubMed2006

Effects of Enterococcus faecium NCIMB 10415 as probiotic supplement on intestinal transport and barrier function of piglets.

Many studies report positive effects of probiotic supplementation on the performance and health of piglets. The intention of this study was to describe the effects of Enterococcus faecium NCIMB 10415 on the transport and barrier functions of pig small intestine to improve our understanding of the underlying mechanisms of this probiotic. Ussing chamber studies were conducted with isolated jejunal epithelia of piglets at the age of 14, 28, 35 and 56 days. Jejunal tissues of the control group were compared with epithelia of piglets that had received a diet supplemented with the probiotic Enterococcus faecium NCIMB 10415. Transport properties (absorption and secretion) of the epithelia were examined by mucosal addition of glucose or L-glutamine or by serosal addition of PGE2. Electrophysiology of the epithelia was continuously recorded and the change in short circuit current (Isc) was determined. Paracellular permeability was measured by measuring the flux rates of mannitol. The increase of Isc caused by mucosal addition of glucose was, at all glucose concentrations, higher in the probiotic group compared with the control group. However, the difference (up to 100% of the control) was not significant. The increase of Isc after the mucosal addition of L-glutamine (12mmol/l) was higher in the tissues of the probiotic group but did not reach significance. Serosal PGE2 induced a significantly higher increase of Isc in tissues of the probiotic group at the age of 28 days. No consistent differences were observed in mannitol transport rates between the feeding groups. Significant age-dependent alterations of absorptive and secretory properties of the jejunal epithelium were observed; these were independent of the treatment. A probiotic supplementation seems to influence transport properties of small intestine epithelium. The increased absorption of glucose could be interpreted as a positive effect for the animal.

Age Factors↗
PubMed2000

Retinol and retinol-binding protein: gut integrity and circulating immunoglobulins.

Vitamin A (retinol) is required to maintain immunity and epithelial turnover and is a key micronutrient needed for combating infection. Vitamin A actions on the immune system are diverse and cannot be accounted for by a single effect or mechanism. The actions of retinol in maintaining gut integrity in humans and immunoglobulin levels in mice was investigated. For 30 children, performance on the lactulose/mannitol test, a test commonly used to assess intestinal barrier function, was inversely correlated (P=.012) with serum retinol concentrations. Thus, children with lower serum retinol, and presumably poorer vitamin A nutritional status, are more likely to have impaired intestinal integrity. Knockout mice that have impairments in plasma retinol transport have circulating immunoglobulin levels that are half those observed in matched wild type mice. No differences were observed in B and T cell populations present in spleen, thymus, and bone marrow.

Animals↗
PubMed1994

Early morphological changes in Crohn's disease. Transmission electron-microscopic findings and their interpretation: an overview.

Recent ultrastructural investigations revealed early epithelial lesions in Crohn's disease, while a specific morphological pattern was not identifiable. An increase in plasma cells, lymphocytes, macrophages, mast cells, eosinophilic and neutrophilic granulocytes, as well as focal edema and inflammation of tissue structures was seen in the lamina propria, submucosa and deeper layers. The results are consistent with the frequent discussion about a pathogenetically significant defect of the mucosal 'barrier function', which consists of mechanical, cellular, humoral, immunological and nonimmunological mechanisms, including different histotopographically defined lines of defense of the epithelium and lamina propria. An intact epithelial layer plays an important role as the first line of defense. It is evident that components of the epithelial barrier (absorptive cells, goblet cells, Paneth cells, M cells) show ultrastructural signs of alteration or injury, while the primary agent or event remains unknown. Another pathomechanism would be a preexisting defect in intestinal 'barrier function'. Such a defect would result in an increased uptake of, or an inadequate immune reaction to, ubiquitously occurring antigens/agents (with genetic predisposition). However, no primary defect of epithelial or inflammatory cells has been definitely identified so far. Direct toxic damage of tissue secondarily introducing the inflammatory changes is also possible. Although the morphological alterations in Crohn's disease are not yet clearly understood and exactly interpreted, transmission electron microscopy has been helpful in defining early lesions and has led to further knowledge about the pathogenesis of this disease.

Crohn Disease↗
PubMed1998

Changes, with age, in the phospholipid content of the intestinal mucus layer of the newborn rabbit.

BACKGROUND/PURPOSE: The high incidence of bacterial translocation in newborns is thought to be caused, in part, by the immaturity of the intestinal mucosal barrier. Recently, intestinal mucus phospholipids (PL) have been reported to be important factors in the function of this mucosal barrier. The aim of this study was to quantify changes, with age, in the intestinal mucus PL of the newborn rabbit. METHODS: Mucus was gently scraped from the small intestinal mucosal surface of rabbits of different ages (0, 7, 14, and 28 days old and adult; n = 6 for all groups). PL was extracted from the mucus and was separated by two-dimensional thin-layer chromatography. The isolated phospholipid spots were quantified for their phosphorus content. RESULTS: Total PL content of the mucus decreased significantly with age (day 0, 21+/-2; day 7, 16+/-4; day 14, 9+/-3; day 28, 2+/-1; adult, 1+/-1 micromol/g wet mucus; P = .0001). Phosphatidylcholine and phosphatidylethanolamine levels in the adult rabbits were significantly lower in comparison with the 0-, 7-, and 14-day-old pups (P < .05). In contrast, lysophosphatidylcholine and lysophosphatidylethanolamine were significantly higher in the 28-day-old and adult rabbits in comparison with the 0-, 7-, and 14-day-old pups (P < .05). Phosphatidylinositol + phosphatidylserine levels in 7-day-old rabbits was significantly higher compared with adult rabbits. There was no significant difference in the composition of sphingomyeline between groups. CONCLUSION: Significant changes in the content and composition of the intestinal mucus phospholipids were observed during the first month of life in rabbits.

Aging↗
PubMed1999

Comparison of intestinal function in human immunodeficiency virus-seropositive patients in Kampala and London.

BACKGROUND: White homosexual men with human immunodeficiency virus (HIV) show progressive impairment of intestinal function assessed in terms of intestinal permeability and absorptive capacity. In this study we aimed to determine the effects of heterosexually acquired HIV on small-intestinal function in native Africans, among whom there is a high prevalence of tropical enteropathy. METHODS: Intestinal absorptive capacity (using 3-O-methyl-D-glucose, D-xylose, and L-rhamnose) and permeability (differential 5-h urinary excretion of lactulose/L-rhamnose) were assessed in healthy white (n = 57) and black (n = 14) controls in London, apparently healthy black Africans in Kampala, Uganda (n = 26), HIV-infected patients with (n = 9) and without (n = 30) diarrhoea in Kampala, and 39 white homosexual men with HIV in London who were stratified to resemble the African patient group. RESULTS: Intestinal integrity and absorptive capacity were significantly (P < 0.01) impaired in both black controls in London and apparently healthy black Africans, compared with white controls. HIV-infected white and black patients without diarrhoea did not differ significantly from white and black African controls, respectively, with the exception of increased intestinal permeability among the white patients. White and black African patients with HIV/acquired immunodeficiency syndrome (AIDS) and diarrhoea were found to have marked malabsorption and increased intestinal permeability. Although the relative increase in intestinal permeability was similar in the two groups, by far the largest values for intestinal permeability were found among black Africans with HIV/AIDS and diarrhoea. CONCLUSIONS: Whites and blacks differ with regard to intestinal barrier function. HIV-positive black Africans without gastrointestinal symptoms differ insignificantly from white Londoners with homosexually acquired disease, whereas those with gastrointestinal symptoms have markedly abnormal indices of small-intestinal function with severely comprised intestinal integrity.

Acquired Immunodeficiency Syndrome↗