Investigation of intestine and liver function in cirrhosis using combined sugar oral loads

Active and passive intestinal absorption and the efficiency of hepatic galactose clearance were studied in 12 patients with liver cirrhosis and 8 healthy control subjects using differential absorption techniques in which paired sugar markers were ingested simultaneously. Such differential absorption procedures overcome the effects of variation in gastric emptying, intestinal transit, distribution space and renal clearance which could invalidate tests incorporating a single marker only. In the cirrhotic group, active absorption of D-xylose (D-xyl) compared with that of 3-O-methyl-D-glucose (3-OMG), indicated by the ratio of D-xyl/3-OMG concentration in plasma, showed no reduction in respect to the control group. The passive intestinal permeability to lactulose (lac) compared with that of L-rhamnose (rham), indicated by urinary lac/rham excretion ratio, was not raised. These findings indicate no dysfunction of small intestinal mucosa in cirrhotic patients in spite of the clinical evidence of portal hypertension. Urinary galactose (gal) excretion after oral load was 10 times higher in the cirrhotic group (P less than 0.001). The gal/3-OMG excretion ratio correlated well with galactose elimination capacity as assessed by an intravenous method. Estimation of plasma D-xyl/3-OMG concentration and both urinary lac/rham and gal/3-OMG excretion ratios after appropriate oral loads provided a convenient and simultaneous evaluation of intestinal absorption, permeability and hepatic galactose elimination.     

Comparison of Four Markers of Intestinal Permeability in Control Subjects and Patients with Coeliac Disease

Bjarnason I, Maxton D, Reynolds AP, Catt S, Peters TJ, Menzies IS. Comparison of four markers of intestinal permeability in control subjects and patients with coeliac disease. Scand J Gastroenterol 1994;29:630-639

Background: Controversy surrounds the issue of intestinal permeability in patients with coeliac disease, polyethylene glycol 400 indicating reduced and di-/mono-saccharide urine excretion ratios and ^5lCr-labeled ethylenediaminetetraacetic acid (EDTA) indicating increased permeability.

Methods: We assessed the suitability of polyethylene glycol 400, L-rhamnose, lactulose, and ⁵¹Cr-EDTA as markers of intestinal permeability by assessing urine excretions after simultaneous intravenous instillation of these markers and after oral administration in normals and patients with coeliac disease.

Results: After intravenous administration the 24-h urine excretion of polyethylene glycol 400, L-rhamnose, lactulose, and ⁵¹Cr-EDTA was 40%, 72%, 93%, and 97%, respectively. There was no significant difference between controls and patients with coeliac disease. Oral administration of the markers in an iso- and hyperosmolar test solution demonstrates reduced permeation due to an osmotic retention effect of lactulose. In contrast, hyperosmolar glycerol increases permeation of all markers except L-rhamnose. Timing of urines and altering osmolality is important for the behaviour of individual markers but does not enhance the discrimination between controls and patients when the differential urine excretion of lactuIose/L-rhamnose is used. The sensitivity of the urine excretion ratio of Iactulose/L-rhamnose was comparable to that of ⁵¹Cr-EDTA used by itself. Whereas lactulose/L-rhamnose and ⁵¹Cr-EDTA showed increased intestinal permeability in coeliac disease, the permeation of polyethylene glycol was reduced. Permeation of the markers did not correlate significantly with jejunal histology. Conclusions: Correlations of marker permeation rates with test dose osmolality in controls and patients with coeliac disease shows a variable lack of conformity, suggesting that the markers may permeate the intestine by different routes, which are affected to a different extent in coeliac disease.     

Reduced hepatic blood flow and intestinal malabsorption in severe falciparum malaria

We have studied intestinal function and liver blood flow in Thai adults with complicated and uncomplicated falciparum malaria. The absorption of 3 orally administered test sugars, D-xylose, 3-O-methyl-D-glucose, and L-rhamnose, was greatly reduced in complicated malaria, while the lactulose/rhamnose absorption ratio was significantly increased. Hepatic blood flow was concomitantly reduced in severe malaria. These deviations reverted to normal in convalescence. Neither sugar absorption nor liver blood flow was reduced in uncomplicated falciparum malaria.     

Geography of intestinal permeability and absorption

BACKGROUND: Intestinal morphology and function vary geographically. AIMS: These functions were assessed in asymptomatic volunteers in European, North American, Middle Eastern, Asian, African, and Caribbean countries. METHODS: Five hour urine collections were obtained from each subject following ingestion of a 100 ml iso-osmolar test solution containing 3-0-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose after an overnight fast, to assess active (3-0-methyl-D-glucose) and passive (D-xylose) carrier mediated, and non-mediated (L-rhamnose) absorption capacity, as well as intestinal permeability (lactulose:rhamnose ratio). RESULTS: A comparison of results for subjects from tropical countries (n=218) with those resident in the combined temperate and subtropical region (Europe, United States, Qatar) (n=224) showed significant differences. Residents in tropical areas had a higher mean lactulose:rhamnose ratio and lower mean five hour recoveries of 3-0-methyl-D-glucose, D-xylose, and L-rhamnose, indicating higher intestinal permeability and lower absorptive capacity. Investigation of visiting residents suggested that differences in intestinal permeability and absorptive capacity were related to the area of residence. Subjects from Texas and Qatar, although comprised of several ethnic groups and resident in a subtropical area, showed no significant difference from European subjects. CONCLUSIONS: There are clearly demarcated variations in intestinal permeability and absorptive capacity affecting asymptomatic residents of different geographical areas which correspond with the condition described as tropical enteropathy. Results suggest the importance of environmental factors. The parameters investigated may be relevant to the predisposition of the indigenous population and travellers to diarrhoeal illness and malnutrition. Intestinal function in patients from the tropics may be difficult to interpret, but should take into account the range of values found in the asymptomatic normal population.     

Intestinal absorption and unmediated permeation of sugars in post-infective tropical malabsorption (tropical sprue)

Differential absorption of D-xylose and 3-O-methyl-D-glucose, and unmediated intestinal permeation of lactulose and L-rhamnose has been investigated in 14 patients with diarrhoea following tropical exposure and in 16 healthy control subjects. Five had malabsorption of fat, D-xylose and B12 ('tropical malabsorption' (TM) group), and that was absent or minimal in the others ('tropical diarrhoea' (TD) group). After combined ingestion of the four test sugars in iso-osmolar solution a marked depression in plasma D-xylose concentration (with a slow rise) occurred in all of the TM group; the TD group did not differ significantly from the controls. In contrast, 3-O-methyl-D-glucose absorption was similar in all three groups. Urine analysis demonstrated that intestinal permeation of lactulose was increased and that of rhamnose decreased in the TM group compared with the controls. Ingestion as a hyperosmotic solution further enhanced abnormal lactulose permeation in the TM group. Although some of the TD group showed one or the other of these changes, discrimination of the TM group from the TD and control groups was improved when results were expressed as lactulose/rhamnose differential permeation ratios, especially when using a hyperosmotic stress. Similar abnormalities have previously been demonstrated in untreated gluten-induced enteropathy (coeliac disease). The magnitude of the absorption defects demonstrated in TM are more severe than would be anticipated from the jejunal mucosal abnormalities alone; this suggests that there is probably significant pathology in the distal small intestine (including the ileum) in TM.     

Local effect of adenosine 5'-triphosphate on indomethacin-induced permeability changes in the human small intestine

BACKGROUND: Nonsteroidal anti-inflammatory drug (NSAID) use is associated with an elevated risk of gastrointestinal damage. As adenosine 5'-triphosphate (ATP) may play a protective role in the small intestine, our objective was to determine the local effect of ATP on small intestinal permeability changes induced by short-term challenge of the NSAID indomethacin in healthy humans. METHODS: Mucosal permeability of the small intestine was assessed by the lactulose/rhamnose permeability test, that is, ingestion of a test drink containing 5 g lactulose and 0.5 g L-rhamnose followed by total urine collection for 5 h. Urinary excretion of lactulose and L-rhamnose was determined by fluorescent detection high-pressure liquid chromatography (HPLC). Basal small intestinal permeability was assessed as a control condition. As a model of increased small intestinal permeability, two doses of indomethacin were ingested before ingestion of the test drink (75 mg and 50 mg at 10 h and 1 h before the test drink, respectively). Concomitantly with indomethacin ingestion, placebo or 30 mg/kg ATP was administered through a naso-intestinal tube. RESULTS: Median urinary lactulose/rhamnose ratio (g/g) in the control condition was 0.023 (interquartile range: 0.013-0.041). Compared with the control condition, urinary lactulose/rhamnose ratio after ingestion of indomethacin and administration of placebo was significantly increased [0.042 (0.028-0.076); P<0.01]. In contrast, urinary lactulose/rhamnose ratio after indomethacin ingestion plus ATP administration [0.027 (0.020-0.046)] was significantly lower than the lactulose/rhamnose ratio in the placebo condition (P<0.01). CONCLUSIONS: Topical ATP administration into the small intestine during short-term challenge of the NSAID indomethacin attenuates the NSAID-induced increase in small intestinal permeability in healthy humans.     

The Effect of Ingested Lactulose on Absorption of L-Rhamnose,D-Xylose,and 3-O-Methyl-D-Glucose in Subjects with Ileostomies

Jenkins AP, Menzies IS, Nukajam WS, Creamer B. The effect of ingested lactulose on absorption of L-rhamnose, D-xylose. and 3-O-methyl-D-glucose in subjects with ileostomies. Scand J Gastroenterol 1994;29:820-825.

Background: We have previously shown that small oral doses of poorly absorbed solute can significantly reduce absorption of test sugars in normal volunteers. To confirm these results and investigate the underlying mechanism, the effects of lactulose on absorption of three test sugars in subjects with ileostomies were studied. Methods: Ten fasted subjects with ileostomies ingested an isosmolar test solution containing 2.5g 3-O-methyl-D-glucose, 5.0g D-xylose, 1.0g L-rhamnose, and 50μCi ⁵¹Cr-labelied ethylenediaminetetraacetic acid together with a blue dye transit marker. Urine was collected for time periods of 0-5 h and 5-24 h, to measure excretion of absorbed sugars, and ileostomy effluent was saved from 0-5 h and from 5 h until blue dye transit marker was no longer present, to measure small-bowel output of unabsorbed sugars. After 1 week the test was repeated, including 5 g lactulose in the test solution. Results: Inclusion of lactulose in the test solution significantly reduced the 5 h and 24 h urine excretion of l -rhamnose and D-xylose but not that of 3-O-methyl-D-glucose and increased 0- to 5-h and total ileostomy output of L-rhamnose and D-xylose but not of 3-O-methyl-D-glucose. The presence of lactulose also reduced the time for first appearance of the blue dye transit marker in the effluent and increased effluent volume together with output of electrolyte. Conclusion: Poorly absorbed solute reduces intestinal absorption by retention of fluid and electrolyte, with subsequent intraluminal dilution and acceleration of transit.     

肝硬化患者腹水中细菌DNA与相关因素的关系

目的 探讨肝硬化患者腹水中细菌DNA与血浆内毒素、肠通透性、肠道菌群等因素的关系. 方法 选取失代偿期肝硬化伴腹水患者55例,于入院当日或次日抽取腹水行腹水中细菌DNA的提取及PCR扩增,同时行腹水常规、需氧菌及厌氧菌培养检查,于入院次日测定血浆内毒素、肠通透性并进行肠道菌群分析,同时测定血常规、肝肾功能、凝血功能等生物化学指标.30例健康成年人作为正常对照,行除腹水之外的上述检查. 结果 55例肝硬化患者腹水细菌培养均为阴性,其中19例(34.55%)患者腹水中检测到细菌DNA.与细菌DNA阴性组比较,细菌DNA阳性组患者的凝血酶原活动度明显降低(t=-3.184,P=0.002),而肝功能Child-Pugh评分(t=3.224,P=0.002)和腹水白细胞计数(t'=4.088,P=0.001)明显升高.与正常对照组比较,肝硬化患者血浆内毒素水平(t=13.705,P=0.000)、尿中乳果糖/甘露醇(L/M,t'=28.568,P=0.000)和肠道肠杆菌数量(t=2.912,P=0.005)明显升高,而肠道双歧杆菌数量明显减少(t=-3.669,P=0.000).与腹水中细菌DNA相关的指标为肠道肠杆菌数量(P=0.007)和凝血酶原活动度(P=0.011).结论 肝硬化患者发生腹水细菌移位的关键因素是肠腔细菌过度生长,并与肝病的严重程度相关.     

Intestinal permeability in patients with Crohn's disease and their first degree relatives.

It has been reported that intestinal permeability to polyethylene glycol 400 is increased in patients with Crohn's disease and their apparently unaffected first degree relatives. Because of the implications that these findings have for the aetiology of Crohn's disease these studies were repeated. Patients with Crohn's disease (n = 28) and 32 first degree relatives from 11 families underwent a polyethylene glycol 400 (PEG400) intestinal permeability test and a hyperosmotic (1500 mosmol/l) absorption/permeability test using 3-0-methyl-D-glucose, D-xylose, L-rhamnose, lactulose, and 51chromium labelled ethylenediamine-tetraacetate. The five hour urine excretion of polyethylene glycol 400 did not differ significantly between controls (n = 25) and first degree relatives, 25.5 (3.3)% v 24.6% (4)% (mean(SD)) p greater than 0.1, respectively. Patients with small bowel involvement excreted significantly less (p less than 0.01) polyethylene glycol 400 (16.3 (4.6)% than controls while those with Crohn's colitis did not (26.4 (3.9)% p greater than 0.1). The permeation of the monosaccharides in patients with Crohn's disease and their first degree relatives did not differ from normal subjects. The permeation of lactulose and 51chromium ethylenediaminetetraacetate was not significantly altered in first degree relatives but was significantly increased in the patients, as was the lactulose/L-rhamnose urine excretion ratio which is a specific measure of small intestinal permeability. These studies show normal absorption and permeability in first degree relatives of patients with Crohn's disease. A genetically determined abnormality of intestinal permeability is not likely to be an important aetiological factor in Crohn's disease.     

Gut permeability in patients with acute pancreatitis

BACKGROUND: The bacterial contamination of pancreatic necrosis in acute pancreatitis is supposed to occur through translocation of intestinal bacteria. Increased gut permeability may be the initial phenomenon in this process. To test the hypothesis that gut permeability is increased in acute pancreatitis a clinical study was made where gut absorption and permeability were assessed with multi-sugar probes in patients with acute pancreatitis within 2 days after admission to hospital and again after recovery of disease. METHODS AND RESULTS: Twenty-three patients with acute pancreatitis and 20 healthy controls were studied. According to Atlanta classification, 15 patients had mild and 8 patients severe pancreatitis. Gut absorption, assessed as the 5-h urine excretion of L-rhamnose, D-xylose and 3-O-methylglucose, was decreased in patients with acute pancreatitis and more pronounced in patients with severe pancreatitis (L-rhamnose and D-xylose: P < 0.001; 3-O-methylglucose: P < 0.05). Gut permeability, assessed as the ratio of lactulose/L-rhamnose, was increased in severe pancreatitis (0.16 +/- 0.13, 0.07 +/- 0.03, 0.04 +/- 0.04; severe pancreatitis, mild pancreatitis, controls, respectively; P < 0.001 between three groups, P < 0.05 between pancreatitis groups). CONCLUSIONS: Gut absorption capacity is decreased and gut permeability is increased in patients with acute pancreatitis. Patients with severe pancreatitis may be more exposed to impaired gut barrier function.     

The effect of poorly absorbed solute on intestinal absorption

To determine the effects of poorly absorbed solute on intestinal absorption, the urinary recovery of ingested lactulose, L-rhamnose, D-xylose, and 3-O-methyl-D-glucose was measured after simultaneous ingestion of various 'loads' of mannitol given in iso-osmolar solution. Mannitol reduced intestinal uptake of the poorly absorbed test sugars, lactulose and L-rhamnose; uptake of D-xylose and 3-O-methyl-D-glucose, which are absorbed by carrier-mediated transport largely from the jejunum, was less affected. The dose-response effect of mannitol on the absorption of L-rhamnose was approximately exponential; doses of 5, 10, and 20 g mannitol reduced the average urinary excretion of L-rhamnose by 34.7%, 51.7%, and 61.2%, respectively. In this respect, an osmotically equivalent load of lactulose, ingested as 'solute', was approximately twice as effective as mannitol in reducing L-rhamnose absorption, probably because lactulose is more poorly absorbed than mannitol (less than 1.0% versus 32-41%). Ingestion of other poorly absorbed solutes such as raffinose, sorbitol, xylitol, magnesium sulphate, and sodium sulphate also significantly depressed the absorption of L-rhamnose; in contrast, more efficiently absorbed solutes, such as sodium chloride, glucose, glycerol, and urea had little effect.     

Abnormal intestinal permeability to sugars in diabetes mellitus

Summary A test of intestinal mucosal function which utilizes the differential permeability of L-rhamnose and lactulose has been reported to be helpful in the diagnosis of gluten-sensitive enteropathy. We have applied this test to 48 male subjects with diabetes mellitus to evaluate its usefulness as a screening test in diabetic patients and to further study sugar absorption in these individuals. Total urinary lactulose excretion in the 13 healthy control subjects was 54.5 ± 8.5 mg/5 h, while excretion by diabetic patients was increased at 116.1 ± 15.7 mg/5 h (p < 0.01). Similarly, total L-rhamnose excretion by diabetic patients was significantly higher (139.7 ± 14.3 mg/5 h vs 84.3 ± 18.4 mg/5 h, p<0.05). The ratio of percent urinary excretion for lactulose/L-rhamnose (L/R ratio) for diabetic patients (0.197 ± 0.024) was not different from the control subjects (0.151 ± 0.2). Nine out of 48 diabetic patients studied had lactulose/L-rhamnose ratios higher than the mean plus two standard deviations of the control group, which might lead to the diagnosis of small bowel mucosal disease. Although we may have been detecting subclinical mucosal disease or gluten sensitive enteropathy in a subgroup, it appears that this test of intestinal mucosal function should be interpreted with caution in diabetic patients.     

Intestinal permeability is increased in patients with advanced cirrhosis

BACKGROUND/AIMS: The dysfunction of the intestinal barrier is a factor that has been related to bacterial translocation from lumen to extra-intestinal sites and consequently to the development of spontaneous bacterial peritonitis. The aim of this study was to investigate if the alterations of the intestinal barrier in cirrhosis are related with the degree of liver failure and associated with other clinical complications. METHODOLOGY: Intestinal permeability was assessed by means of the lactulose/mannitol test in 79 cirrhotic and 25 controls subjects. They received 10 g of lactulose and 5 g of mannitol. Lactulose and mannitol were measured in a five-hour urinary volume. RESULTS: Lactulose/mannitol ratio was significantly higher in cirrhotic patients than in controls (p = 0.03). This was more evident in end-stage cirrhosis. Patients with ascites, or encephalopathy showed a statistically significant increase in lactulose/mannitol ratio when compared to patients without these complications. CONCLUSIONS: The increased intestinal permeability is related to the progression of the liver disease and is more relevant with overt clinical complications. This is due to an increased absorption of lactulose. However, as liver disease progresses, mannitol absorption is progressively reduced, probably due to a reduced surface of absorption, and these events are more relevant in patients with overt clinical complications.     

Increased intestinal macromolecular permeability and urine nitrite excretion associated with liver cirrhosis with ascites

AIM： To determine intestinal permeability, the serum tumor necrosis factor （TNF）-α level and urine nitric oxide （NO） metabolites are altered in liver cirrhosis （LC） with or without ascites. METHODS： Fifty-three patients with LC and 26 healthy control subjects were enrolled in the study. The intestinal permeability value is expressed as the percentage of polyethylene glycol （PEG） 400 and 3350 retrieval in 8-h urine samples as determined by high performance liquid chromatography. Serum TNF-α concentrations and urine NO metabolites were determined using an enzyme-linked immunosorbent assay （ELISA） and Greiss reaction method, respectively. RESULTS： The intestinal permeability index wassignificantly higher in patients with LC with ascites than in healthy control subjects or patients with LC without ascites （0.88 ± 0.12 vs 0.52 ± 0.05 or 0.53 ± 0.03, P 〈 0.05） and correlated with urine nitrite excretion （r = 0.98）. Interestingly, the serum TNF-α concentration was significantly higher in LC without ascites than in control subjects or in LC with ascites （198.9 ± 55.8 pg/mL vs 40.9 ± 12.3 pg/mL or 32.1 ± 13.3 pg/mL, P 〈 0.05）. Urine nitrite excretion was significantly higher in LC with ascites than in the control subjects or in LC without ascites（ 1170.9± 28.7 μmol/L vs 903.1 ± 55.1 μmol/L or 956.7 ± 47.7 μmol/L, P 〈 0.05）. COMCLUSIOM： Increased intestinal macromolecular permeability and NO is probably of importance in the pathophysiology and progression of LC with ascites, but the serum TNF-α concentration was not related to LC with ascites.     

Intestinal permeability and absorptive capacity in children with portal hypertension

BACKGROUND: Portal hypertension may affect intestinal function leading to malnutrition in children with liver disease. The aim was to determine whether children with portal hypertension with or without liver disease had impaired absorptive capacity and intestinal barrier function (intestinal permeability) and to ascertain whether these abnormalities related to changes in body composition. METHODS: Twenty-six children with portal hypertension were divided according to aetiology into: Group 1 intrahepatic (n = 15) and Group 2 prehepatic (n = 11). Thirty-five children acted as controls. Carbohydrate absorption and intestinal permeability were assessed using a sugar absorption/permeability test and a variety of anthropometric measurements were obtained. RESULTS: 3-O-methyl-D-glucose, D-xylose and L-rhamnose excretion were significantly reduced in both patient groups compared to controls (P < or = 0.008) and the differential urinary excretion of melibiose/rhamnose (intestinal permeability) was significantly increased in Group 1 only (P < 0.05). Anthropometric measurements showed low Z scores in both groups, but there was no significant (P > 0.05) difference between them. There was no significant correlation between urinary excretion of sugars. anthropometric measurements and energy intake. CONCLUSIONS: Increased portal pressure reduces the absorptive capacity of the small intestine, while liver disease itself leads to increased intestinal permeability.     

Histopathology of Crohn's Disease

The relationships among intestinal permeability, advancing human immunodeficiency virus (HIV) infection, and the presence of diarrhoea or weight loss were investigated in 51 HIV patients and 20 healthy controls. Ten patients with untreated coeliac disease were also investigated for comparison. Fasting subjects drank an isosmolar test solution containing D-xylose, lactulose (LL), L-rhamnose (R) and 3-O-methyl-D-glucose. Urine was collected for 5 h, test sugar content being subsequently measured by thin-layer chromatography for the dosing sugars. Intestinal permeability (LL/R excretion ratio) and recovery of D-xylose and 3-O-methyl-D-glucose in urine were abnormal in patients with HIV disease, and especially those with diarrhoea, as they were in coeliac disease. Patients with coeliac disease and HIV disease, especially when diarrhoea and/or weight loss were present, had significantly reduced 5-h excretion of L-rhamnose, D-xylose, and 3-O-methyl-D-glucose. These data indicate that abnormal permeability and reduced intestinal absorption capacity are common in HIV patients, occur at all stages of HIV disease, especially in the presence of diarrhoea, and, with the exception of lactulose permeation, are relatively similar to the alterations seen in coeliac disease.     

Intestinal absorptive capacity, intestinal permeability and jejunal histology in HIV and their relation to diarrhoea.

Intestinal function is poorly defined in patients with HIV infection. Absorptive capacity and intestinal permeability were assessed using 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose in 88 HIV infected patients and the findings were correlated with the degree of immunosuppression (CD4 counts), diarrhoea, wasting, intestinal pathogen status, and histomorphometric analysis of jejunal biopsy samples. Malabsorption of 3-O-methyl-D-glucose and D-xylose was prevalent in all groups of patients with AIDS but not in asymptomatic, well patients with HIV. Malabsorption correlated significantly (r = 0.34-0.56, p < 0.005) with the degree of immune suppression and with body mass index. Increased intestinal permeability was found in all subgroups of patients. The changes in absorption-permeability were of comparable severity to those found in patients with untreated coeliac disease. Jejunal histology, however, showed only mild changes in the villus height/crypt depth ratio as compared with subtotal villus atrophy in coeliac disease. Malabsorption and increased intestinal permeability are common in AIDS patients. Malabsorption, which has nutritional implications, relates more to immune suppression than jejunal morphological changes.     

Malabsorption and nutritional abnormalities in patients with liver cirrhosis

Cirrhotic patients often present muscle and adipose tissue depletion as well as reduced visceral protein concentration. Impaired absorption of nutrients may contribute to this altered nutritional status. To verify this hypothesis fecal fat excretion, intestinal mucosal function evaluated by means of the combined sugar oral load test, and intestinal clearance of alpha-1-Antirypsin were studied in 25 cirrhotic patients with clinical and biochemical signs of liver insufficiency and with portal hypertension. About 50% of the patients showed clinical evidence of malnutrition. Three of the 12 well-nourished, and 8 of the 13 malnourished patients presented significant steatorrhoea. Cirrhotics showed no impairment in mediated malabsorption and in passive permeability, as plasma D-xylose/3-O-methyl-glucose concentration and urinary lactulose/L-rhamnose excretion ratios were within the normal range. An increased value of alpha-1-Antitrypsin clearance was found only in two patients. These findings indicate that fat malabsorption is frequent in cirrhotic patients, particularly when malnourished, and does not depend on the presence of mucosal intestinal damage.     

Oral Chenodeoxycholic Acid Increases Small Intestinal Permeability to Lactulose in Humans

In animals, chenodeoxyholic acid (chenodiol) causes significant small intestinal mucosal injury which is paralleled by increased intestinal permeability. The objective of this study was to determine whether chenodiol increases small intestinal mucosal permeability in humans. This was assessed in a before-after trial by collecting urine from nine fasted healthy male volunteers for 3 h after oral intake of an isotonic solution containing 1 g mannitol, 5 g L-rhamnose and 10 g lactulose, all nondigestible sugars. After at least 72 h, this was repeated 1 h after taking 750 mg of chenodiol orally. The amount of each sugar excreted in the urine was quantified by high performance liquid chromatography. Chenodiol doubled the percent urinary excretion of lactulose from 0.21 +/- 0.12 (SD) to 0.42% +/- 0.25 (p less than 0.02) and the ratio of lactulose to mannitol or to rhamnose [0.012 +/- 0.005 to 0.027 +/- 0.013 (p less than 0.01) and 0.045 +/- 0.022 to 0.087 +/- 0.039 (p less than 0.05), respectively]. Oral administration of 750 mg chenodiol is associated with increased small intestinal permeability to lactulose in humans, supporting the possibility that this drug may also cause acute small intestinal mucosal injury.     

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.