Cma Bijleveld

Hepatocanalicular bile salt export pump deficiency in patients with progressive familial intrahepatic cholestasis

BACKGROUND & AIMS Progressive familial intrahepatic cholestasis (PFIC), an inherited liver disease of childhood, is characterized by cholestasis and either normal or increased serum gamma-glutamyltransferase activity. Patients with normal gamma-glutamyltransferase activity have mutations of the FIC1 locus on chromosome 18q21 or mutations of the BSEP gene on chromosome 2q24. Also, patients with bile acid synthesis defects have low gamma-glutamyltransferase activity. We investigated expression of the bile salt export pump (BSEP) in liver samples from patients with a PFIC phenotype and correlated this with BSEP gene mutations. METHODS BSEP and multidrug resistance protein 2 (MRP2) expressions were studied by immunohistochemistry in liver specimens of 28 patients and BSEP gene mutation analysis in 19 patients. Bile salt kinetics were studied in 1 patient. RESULTS Sixteen of 28 liver samples showed no canalicular BSEP staining. Staining for MRP2 showed a normal canalicular pattern in all but 1 of these samples. Ten of 19 patients showed BSEP gene mutations; BSEP protein expression was lacking in all 10 patients. No mutations were found in 9 of 19 patients, and in all except 1, BSEP protein expression was normal. Bile salt concentration in bile of BSEP-negative/MRP2-positive PFIC patients was 0.2 +/- 0.2 mmol/L (n = 9; <1% of normal) and in BSEP-positive PFIC patients 18.1 +/- 9.9 mmol/L (n = 3; 40% of normal). The kinetic study confirmed the dramatic decrease of bile salt secretion in BSEP-negative patients. CONCLUSIONS The findings show a close correlation between BSEP gene mutations and canalicular BSEP expression. Biliary secretion of bile salts is greatly reduced in BSEP-negative patients.

Prognosis of extrahepatic biliary atresia.

We carried out a retrospective investigation of the 89 patients with extrahepatic biliary atresia born in The Netherlands during a 10 year period. Of these 89 patients 10 had a diagnostic laparotomy only. Eight patients had an anastomosis between the proximal bile duct and the intestine, and the remaining 71 had hepatic portoenterostomies. Bile drainage was re-established in 46 (65%). After successful hepatic portoenterostomy the development of cholangitis was the most important determinant of long term survival; five year survival was 54% in the 19 patients who had cholangitis and 91% in the 27 who did not. In the whole group of 71 patients the five year survival was 47%. Seventeen patients were at least 5 years of age at the time of writing, three of whom had had liver transplantation. Three patients have cirrhosis and hyperbilirubinaemia, and the other 11 have normal bilirubin concentrations and normal or slightly raised transaminase activities. To improve these results early surgical intervention in all children with extrahepatic biliary atresia is necessary, as are better methods of prophylaxis and treatment of cholangitis.

Non-Invasive Detection of Low-Intestinal Lactase Activity in Children by Use of a Combined 13CO2/H2 Breath Test

BACKGROUND The aim of the study was to diagnose hypolactasia with a higher accuracy than with the traditional H2 breath test. METHODS We used a combined 13C-lactose 13CO2/H2 breath test, which was performed in 33 patients in whom lactase activity was measured. RESULTS Lactase activity was reduced in 13 cases. The sensitivity and specificity of the H2 test were 54% and 90%; those of the 13CO2 test 69% and 70%. False-negative results did not always occur in the same patients. In five of six patients with both test results abnormal, lactase activity was low. In 13 of 15 patients with both test results normal, lactase activity was normal. In 6 of 12 cases with only 1 test abnormal, lactase activity was low. CONCLUSION The combined H2/13CO2 breath test (sensitivity, 85%; specificity, 65%) is more adequate for diagnosis of hypolactasia than the H2 breath test alone.

BENIGN RECURRENT INTRAHEPATIC CHOLESTASIS - ALTERED BILE-ACID METABOLISM

Altered bile acid metabolism has been claimed to play a role in the etiology of benign recurrent intrahepatic cholestasis (BRIC). Therefore, we studied bile acid metabolism in detail in 10 patients with this syndrome. Pool sizes of both primary bile acids were estimated simultaneously, using deuterated cholic acid and chenodeoxycholic acid. The pool sizes of cholic acid and chenodeoxycholic acid, expressed in micromoles per kilogram body weight, were significantly contracted in BRIC patients during a cholestasis-free period: 8.0 +/- 4.2 and 11.7 +/- 4.7, respectively, versus 24.1 +/- 11.7 and 22.9 +/- 7.8 in controls. Fractional turnover rates (per day) for cholic acid and chenodeoxycholic acid were increased: 0.70 +/- 0.29 and 0.58 +/- 0.27, respectively, versus 0.29 +/- 0.12 and 0.23 +/- 0.10 in controls. Bile acid pool composition expressed as percentages in BRIC patients was cholic acid 34 +/- 17, chenodeoxycholic acid 38 +/- 9, deoxycholic acid 27 +/- 18, and lithocholic acid 1 +/- 1, with a glycine to taurine conjugation ratio of 6.7 +/- 4.9. Corresponding values for 32 controls were cholic acid 57 +/- 13, chenodeoxycholic acid 29 +/- 9, deoxycholic acid 14 +/- 9, and lithocholic acid less than 1, with a glycine to taurine conjugation ratio of 2.4 +/- 1.3. Fecal bile acid loss, in micromoles per kilogram body weight per day, was 11.2 +/- 9.0 in BRIC patients compared with 2.8 +/- 1.4 in controls. The serum 7 alpha-hydroxycholesterol level (nanomoles per liter) was significantly increased in BRIC patients: 326 +/- 179 versus 171 +/- 90 in controls. These results suggest that in BRIC patients spillover of bile acids into the colon occurs, which leads to increased fecal bile acid loss and a reduced bile acid pool size. Increased serum 7 alpha-hydroxycholesterol is probably indicative of an accelerated bile acid synthesis rate due to increased activity of cholesterol 7 alpha-hydroxylase, the enzyme catalyzing the first step in the major pathway of bile acid synthesis. The results of our study suggest that in BRIC patients a contracted bile acid pool increases the susceptibility of the liver for cholestatic agents.

Benign recurrent intrahepatic cholestasis (BRIC): evidence of genetic heterogeneity and delimitation of the BRIC locus to a 7-cM interval between D18S69 and D18S64

Abstract Benign recurrent intrahepatic cholestasis (BRIC) is an autosomal recessive liver disease characterized by multiple episodes of cholestasis without progression to chronic liver disease. The gene was previously assigned to chromosome 18q21, using a shared segment analysis in three families from the Netherlands. In the present study we report the linkage analysis of an expanded sample of 14 BRIC families, using 15 microsatellite markers from the 18q21 region. Obligate recombinants in two families place the gene in a 7-cM interval, between markers D18S69 and D18S64. All intervening markers had significant LOD scores in two-point linkage analysis. Moreover, we identified one family in which the BRIC gene seems to be unlinked to the 18q21 region, or that represents incomplete penetrance of the BRIC genotype.

PROGNOSTIC FACTORS FOR LONG-TERM ACTUAL PATIENT SURVIVAL AFTER ORTHOTOPIC LIVER TRANSPLANTATION IN CHILDREN

Background. Orthotopic liver transplantation has become the treatment of choice for children with end-stage liver disease. Although results have improved the last decades, still a considerable number of children die after transplantation. The aim of this study was to analyze long-term actual survival and to identify prognostic factors for such survival rates. Methods. A consecutive series of 66 children receiving transplants who had or could have had a follow-up of at least 5 years was retrospectively analyzed. Actual survival and prognostic factors in relation to patient, donor, and operation related variables were assessed after multivariate analysis. Results. Actual 1-, 3-, and 5-year patient survival was 86%, 79%, and 73%, respectively. A high Child-Pugh (C-P) score or C-P class C, high donor age, high blood loss index, and retransplantation were predictive factors for actual patient survival. A high blood loss index was correlated with biliary atresia, low recipient age and weight, and with previous upper abdominal operations. The duration of stay of the donor at the intensive care unit (ICU) was a predictive factor for retransplantation. Conclusions. Children with diseases eligible for liver transplantation should be seen early in the course of their disease in a transplantation center. All possible measures should be taken during the transplantation procedure to keep the blood loss at a minimum. Children with biliary atresia deserve special attention in this respect. The choice of donors has implications for survival.

Fat absorption in premature infants: The effect of lard and antibiotics

Fat absorption of an adapted cows milk formula was studied in a randomized controlled trial involving two groups of 18 premature infants (mean gestational age±SD: 33.0±2.9 weeks, range 26.5–37.5 weeks). The triglyceride configuration was modified by the use of lard. This modification did not improve the absorption of fat or energy. Also no difference in serum concentrations of cholesterol and tridifference was found. Growth velocity during the study was similar in both groups. Detailed analysis of the data revealed that in infants who received (parenterally) antibiotics (mainly ampicillin and netilmicin) a higher coefficient of fat absorption (+20%,P<0.01) and of energy absorption (+8%,P=0.03) was found. Based on these results, we find no support for the use of lard in adapted cows milk infant formulas to improve fat absorption. In studies of fat and energy absorption the effects of antibiotics have to be taken into account.

The Metabolic Importance of Unabsorbed Dietary Lipids in the Colon

Digestion and absorption of lipids is a highly efficient process. From Western diets about 95% will be absorbed. This implies that together with lipids from endogenous sources 6-8 g of lipids will enter the colon daily. This input significantly increases during various lipid malabsorption syndromes. It has long been assumed that the biological fate of unabsorbed lipids is physiologically not relevant. However, significant microbial lipid metabolism occurs. Circumstantial evidence is arising which supports a role of unabsorbed lipid metabolites in the development of colonic diseases. Lipid metabolites may act as detergents in the colon, leading to mucosal injury and reactive hyperproliferation, which in its turn could promote tumour development. Lipid metabolites could also be transformed in biological active metabolites, which have a tumour promoting potency. More mechanistic information is needed on the colonic metabolic fate of lipids in order to develop strategies for manipulating colonic flora in the prevention of lipid related colonic diseases.Digestion and absorption of lipids is a highly efficient process. From Western diets about 95% will be absorbed. This implies that together with lipids from endogenous sources 6-8 g of lipids will enter the colon daily. This input significantly increases during various lipid malabsorption syndromes. It has long been assumed that the biological fate of unabsorbed lipids is physiologically not relevant. However, significant microbial lipid metabolism occurs. Circumstantial evidence is arising which supports a role of unabsorbed lipid metabolites in the development of colonic diseases. Lipid metabolites may act as detergents in the colon, leading to mucosal injury and reactive hyperproliferation, which in its turn could promote tumour development. Lipid metabolites could also be transformed in biological active metabolites, which have a tumour promoting potency. More mechanistic information is needed on the colonic metabolic fate of lipids in order to develop strategies for manipulating colonic flora in the prevention of lipid related colonic diseases.

The daytime breath hydrogen profile: technical aspects and normal pattern

A method is described for breath sampling which can be used for breath hydrogen estimations not only in clinical practice, but also at home. Sampling of end-expiratory air is performed using a 10-ml syringe with a side hole. The samples are transferred to 3-ml vacuum tubes, which can be stored and mailed without significant loss of hydrogen. The hydrogen concentration is estimated gas chromatographically using 0.4 ml of sampled air. This method was used to assess the breath hydrogen pattern under normal circumstances: the daytime breath hydrogen profile. Fourteen children sampled their breath at 30-min intervals during one full day, and recorded diet and activity. The normal daytime breath hydrogen profile showed a typical pattern. Morning values were low, but the evening values were markedly increased in half of the children. These patterns differed markedly from those registered in three children with carbohydrate malabsorption. The daytime breath hydrogen profile, which is easy to perform and applicable at home, might provide valuable additional information in the investigation of children with suspected carbohydrate malabsorption.

The Use of Complex Carbohydrates in Barley Groats for Determination of the Mouth-to-Caecum Transit Time

Lactulose is often used as a substrate to estimate the mouth-to-caecum transit time (MCTT), but because of osmotic effects the outcome depends on the dose consumed. In this study, barley groats, a complex carbohydrate (CH) that produces a clear breath hydrogen response after consumption, were used. Eight volunteers consumed the same dose of softened barley groats (1.0 g CH/kg body weight) three times. Ten volunteers ate three different doses (0.75, 1.0, and 1.5 g CH/kg body weight). Breath samples were collected every 30 or 60 min for at least 12.5 h and analysed for hydrogen. To study the effect of the particle size of the barley groats or the addition of fat on the MCTT, 11 volunteers consumed barley groats (1.0 g CH/kg body weight) with cream cheese (0.25 g fat/kg body weight) and 5 volunteers ate crushed barley groats (particles of +/- 1 mm, 1.0 g CH/kg body weight). After consumption of 1.0 g CH/kg body weight a mean MCTT of 8.4 +/- 0.4 h was found. After consumption of the high dose, a mean MCTT of 9.0 +/- 0.5 h was found, and after the low dose, 8.5 +/- 0.6 h. Addition of fat resulted in a significantly increased MCTT, presumably caused by retarded stomach emptying (9.2 +/- 0.6 h versus 8.1 +/- 0.5 h in controls). Particle size did not significantly affect the MCTT (7.2 +/- 0.5 h at 1 mm versus 7.8 +/- 0.6 h at normal particle size).(ABSTRACT TRUNCATED AT 250 WORDS)