Faecal sterol output is increased by arachidyl amido cholanoic acid (Aramchol) in rats.

Fatty acid-bile acid conjugates (FABACs) were shown recently to have important and multiple effects on cholesterol metabolism. In human fibroblasts, they were found to markedly enhance cholesterol efflux by an ATP-binding cassette transporter A1-dependent pathway. In C57L/J mice, they increased CYP7A1 activity and RNA expression, while decreasing moderately 3-hydroxy-3-methylglutaryl-CoA reductase activity. In C57L/J mice and in hamsters, they also decreased serum cholesterol levels, whereas in other animals, this effect was not seen in short-term experiments. In the present study, we investigated potential mechanisms of action of arachidyl amido cholanoic acid (Aramchol), with particular reference to biliary and faecal sterol outputs in rats. Supplementation with Aramchol at a dose of 150 mg x kg(-1) x day(-1) increased neutral sterol output by approx. 50%, while the faecal outputs of bile salts and total sterols increased by almost 2-fold. Biliary lipid outputs were not significantly different between the control and FABAC-supplemented animals. These findings indicate an overall catabolic effect of FABACs on body cholesterol.

Fatty acid bile acid conjugates inhibit atherosclerosis in the C57BL/6 mouse model.

OBJECTIVE: The aim of the current research was to study whether fatty acid bile acid conjugates (FABACs) have a beneficial effect on atherosclerosis progression and blood lipid levels in mice. METHODS: C57BL/6 female mice, fed a high-fat Paigen diet, were administered an oral dose of FABAC or DDH2O daily. Quantification of atherosclerotic fatty-streak lesions at the aortic sinus was performed. RESULTS: The FABAC-treated mice showed a significant reduction in the atherosclerotic lesion areas as compared to the control group (p = 0.019). A significant elevation in total cholesterol levels was observed in both the FABAC and control groups. Higher FABAC levels were measured in the high-density lipoprotein fraction as compared to the very-low-density and low-density lipoprotein fractions. CONCLUSION: Our findings demonstrate that FABACs, given orally, reduce the development of atherosclerosis in mice fed a high-fat high-cholesterol diet, despite a lack of effect on plasma lipid levels.

Measles is more prevalent in Crohn's disease patients. A multicentre Israeli study.

The question whether there is a transmissible pathogenetic agent as a cause for Crohn's disease, remains unanswered. Measles virus has been the subject of many intensive studies, in the attempt to find a role for it in the pathogenesis of inflammatory bowel disease. Whether an early infection with measles virus may predispose to Crohn's disease in later life is still not clear. We conducted a large scale multicentre study, in order to obtain sufficient data to answer this question. To do so, we compared inflammatory bowel disease patients, with Crohn's disease or ulcerative colitis, with two matched control groups: clinical controls, and community controls. A total of 531 patients, 271 with ulcerative colitis and 260 with Crohn's disease were interviewed, as well as 903 matched controls. Blood from 104 inflammatory bowel disease patients and 50 controls was tested for antibodies to measles virus. We did not find any differences related to measles vaccination, either in Crohn's disease or in ulcerative colitis. Exposure to measles in childhood was more frequent in Crohn's disease patients than in their controls, the difference being statistically significant (p < 0.05) in relation to community controls. The presence of IgG antibodies to measles virus was higher in patients with Crohn's disease than in patients with ulcerative colitis or controls (p = 0.084). Another observation of interest was the finding that Crohn's disease patients who had measles in childhood, more frequently had large bowel disease than those who had not had measles. These data lead us to postulate that there may be a role for measles infection in Crohn's disease, even if, at present, this role remains unclear.

Effects of current cigarette smoking on clinical course of Crohn's disease and ulcerative colitis.

Cigarette smoking worsens Crohn's disease (CD) but ameliorates ulcerative colitis (UC). In Israel, where there is no epidemiological association of smoking with CD, we examined the effects of current smoking on the course of CD and UC. Patients at nine public hospitals completed a questionnaire detailing their smoking history, disease course and treatments; subjects altering their smoking habit after the onset of disease were excluded. Sixty-four smokers and 144 nonsmokers had CD, and 34 smokers and 158 nonsmokers had UC. No differences were found between CD smokers and nonsmokers for hospitalizations, operations, and requirement for corticosteroid and immunosuppressive treatment. By contrast, UC smokers had less extensive disease than nonsmokers (P < 0.02) and fewer hospitalizations (P = 0.01) and operations (P = 0.025). Our results agree with a minority of studies showing no adverse effect of smoking on the course of CD, and confirm the protective effect of smoking in UC.

Appendectomy is more frequent but not a risk factor in Crohn's disease while being protective in ulcerative colitis: a comparison of surgical procedures in inflammatory bowel disease.

OBJECTIVE: Appendectomy was shown to be protective in patients with ulcerative colitis (UC). There are fewer data in Crohn's disease (CD). Other operations were less studied. The aim of this study was to investigate the prevalence of appendectomy, cholecystectomy, and tonsillectomy, including their timing, in patients with inflammatory bowel disease in comparison to controls. METHODS: Two hundred seventy-one patients with UC and 260 with CD, 475 clinic controls, and 428 community controls were interviewed. RESULTS: Appendectomy was found in 5.5% patients with UC, in 11% of clinic controls (p < 0.05), and 7.7% of community controls (p = not significant). The differences were more significant for appendectomy before onset of disease. Appendectomy was performed in 19.2% of patients with CD, in 10.9% of clinic controls, and in 10.1% of community controls (p < 0.01). However, there were no significant differences when only appendectomy before onset of disease was considered. Cholecystectomy was found in 1.5% of patients with UC, in 6.1% of clinic controls (p < 0.01), and in 4.5% of community controls (p = not significant). The difference remained significant when confined to operations performed before disease onset. No such difference was found in patients with CD. No significant difference was found in the prevalence of tonsillectomy between patients and controls. CONCLUSIONS: Appendectomy is protective in UC; it is more frequent, but not a risk factor in CD. The role of cholecystectomy should be investigated further.

Determination of bile acids in biological fluids by liquid chromatography-electrospray tandem mass spectrometry.

A simple, sensitive, and specific liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) method for the determination of bile acids in human bile has been developed. The bile acids were extracted with a C(18) (octadecyl) reversed-phase column and identified and quantified by simultaneous monitoring of their parent and daughter ions, using the multiple reaction monitoring mode. Identification and quantification of conjugated bile acids in bile was achieved in 5 min. The detection limit was 1 ng, and the determination was linear for concentrations up to 100 ng. The percent recovery of standards made of single conjugated (glycine and taurine) bile acid or of mixture of glycine- or taurine-conjugated cholic acid, chenodeoxycholic acid, deoxycholic acid, ursodeoxycholic acid, and lithocholic acid averaged 71.73% to 95.92%. The percent recovery of the same standard bile acids was also determined by gas chromatography-mass spectrometry (GC-MS), using the selected ion monitoring mode, and averaged 66% to 96%. A biliary bile acid profile of human gallbladder bile was obtained by LC-MS/MS and GC-MS. The results showed a good correlation between the two techniques and no significant differences between the two methods were observed. The LC-MS/MS method was also used for the analysis of serum, urine, and fecal bile acids. In conclusion, LC-MS/MS is a simple, sensitive, and rapid technique for the analysis of conjugated bile acids in bile and other biological samples. - Perwaiz, S., B. Tuchweber, D. Mignault, T. Gilat, and I. M. Yousef. Determination of bile acids in biological fluids by liquid chromatography-electrospray tandem mass spectrometry. J. Lipid Res. 2001. 42: 114;-119.

Fatty acid bile acid conjugates (FABACs)--new molecules for the prevention of cholesterol crystallisation in bile.

BACKGROUND: Cholesterol gall stones are a frequent disease for which at present surgery is the usual therapy. Despite the importance of bile acids it has become evident that phospholipids are the main cholesterol solubilisers in bile. Even phospholipid components, such as fatty acids, have anticrystallising activity. AIM: To synthesise fatty acid bile acid conjugates (FABACs) and study their effects on cholesterol crystallisation in bile in vitro and in vivo. METHODS: FABACs were prepared by conjugation of cholic acid at position 3 with saturated fatty acids of variable chain length using an amide bond. Cholesterol crystallisation and its kinetics (crystal observation time, crystal mass) were studied in model bile, pooled enriched human bile, and fresh human bile using FABACs with saturated fatty acids of varying chain length (C-6 to C-22). Absorption of FABACs into blood and bile was tested in hamsters. Prevention of biliary cholesterol crystallisation in vivo was tested in hamsters and inbred mice. RESULTS: FABACs strongly inhibited cholesterol crystallisation in model as well as native bile. The FABACs with longer acyl chains (C-16 to C-22) were more effective. At a concentration of 5 mM, FABACs almost completely inhibited cholesterol crystallisation in fresh human bile for 21 days. FABACs were absorbed and found in both portal and heart blood of hamsters. Levels in bile were 2-3 times higher than in blood, indicating active secretion. Appreciable levels were found in the systemic circulation 24-48 hours after a single administration. Ingested FABACs completely prevented the formation of cholesterol crystals in the gall bladders of hamsters and mice fed a lithogenic diet. CONCLUSIONS: FABACs are potent inhibitors of cholesterol crystallisation in bile. They are absorbed and secreted into bile and prevent the earliest step of cholesterol gall stone formation in animals. These compounds may be of potential use in cholesterol gall stone disease in humans.

Arachidyl amido cholanoic acid (Aramchol) is a cholesterol solubilizer and prevents the formation of cholesterol gallstones in inbred mice.

We have recently synthesized fatty acid bile acid conjugates (FABAC) that were able to reduce and retard cholesterol crystallization in model and human biles. When given orally, they prevented the formation of cholesterol crystals in the bile of hamsters. The aim of the present study was to determine whether the FABAC are cholesterol solubilizers, whether they can dissolve pre-existing crystals, whether they can prevent the formation of cholesterol gallstones, and to investigate the optimal type of bond between the fatty acid and bile acid. The presence of cholesterol crystals was determined by light microscopy, and the total crystal mass of precipitated crystals was measured by chemical means. Inbred (C57J/L) mice on a lithogenic diet were used to evaluate cholesterol crystal formation, dissolution, and gallstone formation in vivo. Arachidyl amido cholanoic acid (Aramchol) was the FABAC used in the present experiments. At equimolar amounts, the cholesterol-solubilizing capacity of Aramchol was higher than that of taurocholate and similar to that of phosphatidylcholine. The addition of Aramchol dissolved approximately 50% of pre-existing crystals in model bile solutions. The same phenomenon was demonstrated in human bile ex vivo, with a dose-response effect. All inbred mice developed cholesterol crystals in bile after 10-14 d on the lithogenic diet. Thereafter, supplementation of the diet with Aramchol progressively reduced the proportion of mice with crystals to 25% after 28 d. On the lithogenic diet, 100% of inbred mice developed cholesterol gallstones in the gallbladder by day 21. None of the mice whose diet was supplemented with 0.5 mg or 1.0 mg of Aramchol/d developed stones or crystals. FABAC are a new class of molecules that are cholesterol solubilizers and which are able to dissolve cholesterol crystals in bile. Upon oral administration, they dissolve pre-existing cholesterol crystals and prevent the formation of gallstones in gallstone-susceptible mice.

Pregnancy and the biliary tract.

Pregnancy induces many physiological changes, some of which may have pathological results. In population studies, gallstones were found in 6.5% to 8.4% of nulliparous women, and in 18.4% to 19.3% of women with two to three or more pregnancies. In women followed throughout pregnancy, neoformation of gallstones was documented in 3% to 8.1% depending on the population. Some 20% to 30% of these gallstones redissolve postpartum. The frequency of biliary colic during pregnancy is controversial, and the recommended therapeutic approach during pregnancy is conservative. When essential, invasive procedures are relatively well tolerated, preferably during the second trimester. Biliary sludge disappears postpartum in the great majority. Gallstones and sludge are most likely caused by biliary stasis, prolonged intestinal transit and increased cholesterol saturation of bile, which were all demonstrated to occur during pregnancy.

Passive smoking in patients with inflammatory bowel disease: an Israeli multicentre case-control study.

BACKGROUND: The association between smoking and inflammatory bowel disease (IBD) is well established. There are, however, no large scale studies of passive smoking in inflammatory bowel disease and this has never been surveyed in the Jewish population of Israel. AIM: To study the passive smoking exposure of Jewish IBD patients in Israel in a large scale multicentre study. METHODS: Patients with established IBD, aged 18-70 years, were interviewed regarding smoking and other habits. Two controls, one clinic and one neighbourhood, matched by age, sex, community group, and education, were sought for each subject. RESULTS: Five hundred and thirty-four patients (273 ulcerative colitis (UC) and 261 Crohn's disease (CD)), 478 clinic controls and 430 community controls were interviewed. There were no significant differences in the passive smoking habits between IBD patients and their controls. Fifty-one percent of UC patients, 50% of the clinic controls and 58% of the community controls were exposed to passive smoking at home (NS); similar results were found among CD patients (50%, 55% and 56%, respectively). When a quantitative exposure index was used UC patients were significantly less exposed to passive smoking than were their community controls (7.46 +/- 8.40 vs 9.36 +/- 9.46, n = 229, P< 0.031). There was no difference in the exposure to passive smoking among CD patients and their controls. No differences in exposure to passive smoking were found when UC patients who had never smoked were compared with their controls. When the quantitative index was used 'never-smoked' CD patients tended to be less exposed to passive smoking at home than their community controls (5.40 +/- 7.60 vs 8.04 +/- 8.72, P < 0.05). CONCLUSION: There is a lack of association between passive smoking and IBD in Jewish patients in Israel. When a quantitative exposure index was used UC patients were found to be less exposed to passive smoking than their community controls.

Quantitative estimation of attenuation in ultrasound video images: correlation with histology in diffuse liver disease.

RATIONALE AND OBJECTIVES: To determine the relationship between the attenuation of backscatter intensity in B-scan images of the liver and diffuse liver disease in order to assess the usefulness of this method in providing quantitative objective characterization of diffuse liver diseases in general and in fatty liver in particular. METHODS: Twenty-four healthy volunteers and 28 patients with elevated liver enzyme levels who underwent liver biopsy were included in this study. An automatic far-field slope (FFS) algorithm that estimates the decrease in amplitude of the backscattered echo as a function of beam depth was implemented on the noncompensated image that was acquired on a commercial phased-array ultrasound system fitted to a custom-built interface card. The images were processed at a work-station. All scans were acquired repeatedly, read, and graded blindly by experienced ultrasound radiologists. Histology obtained via needle biopsy was reviewed without knowledge of the ultrasound findings. RESULTS: Analysis of the FFS data for fatty infiltration in all patient groups yielded a sensitivity of 67%, a specificity of 77%, a positive predictive value (PPV) of 77%, negative predictive value (NPV) of 67%, and an accuracy of 71%. The mean score of the ultrasound reviewers showed a sensitivity of 82%, a specificity of 66%, a PPV% of 68%, an NPV of 81%, and an accuracy of 72%. Normal FFS values (false-negative) were found in five patients with proved fatty infiltration. All of these patients had coexistent moderate to severe hepatic inflammation. However, FFS data in patients with uncomplicated (pure) fatty infiltration revealed a sensitivity of 100%, a specificity of 80%, a PPV of 89%, an NPV of 100%, and an accuracy of 92%. The best ultrasound score yielded a sensitivity of 100%, a specificity of 60%, a PPV of 80%, an NPV of 100%, and an accuracy of 85% in the same patients. CONCLUSIONS: The data demonstrate an excellent sensitivity (100%) of the FFS values in patients with uncomplicated fatty infiltration. This was also the only group of patients in whom the FFS score was superior to the radiologists' best score. The FFS method can be used as a tool to follow up the response to a clinical or research treatment and to obtain standardization of pattern interpretation independently of the individual reader.

Lack of association between smoking and Crohn's disease but the usual association with ulcerative colitis in Jewish patients in Israel: a multicenter study.

OBJECTIVE: The association between smoking and inflammatory bowel disease (IBD) is well established, but data in Jewish patients in Israel were discrepant. The aim of this study was to examine the smoking habits of Jewish IBD patients in Israel in a large scale, multicenter study. METHODS: Patients with established IBD aged 18-70 yr were interviewed in relation to smoking and other habits. Two controls (one clinic and one neighborhood control matched by age, sex, community group, and education) were sought for each subject. RESULTS: A total of 534 patients (273 ulcerative colitis [UC], and 261 Crohn's disease [CD]), along with 478 clinic controls and 430 neighborhood controls, were interviewed. There was no significant difference in the smoking habits between CD patients and their controls. Of patients with CD, 24.5% were current smokers, as compared to 19.9% of clinic controls and 25.2% of neighborhood controls (NS). The odds ratio for CD in current smokers was 1.30 (95% confidence interval 0.85-1.99) versus clinic controls, and 0.96 (0.63-1.46) versus neighborhood controls. There were also no significant differences in the proportion of ex-smokers between the groups. Only 12.9% of UC patients were current smokers versus 21.9. % Clinic controls, and 26.4% community controls (p<0.005). The proportions of ex-smokers were higher in UC patients 29.7% versus 25.9%, and 19.5% in their respective controls (p<0.001 vs. community controls). No significant differences were found in the proportions of never-smokers between IBD patients and controls. All the above trends were similar in four different parts of the country. The proportion of current smokers in UC decreased with the extent of disease (19.7% in proctitis, 13.6% in left-sided, and 4.5% in total colitis) (p<0.05). Patients with UC were more likely to be light smokers(1-10 cigarettes/day), whereas patients with CD were more likely to be moderate smokers (11-20 cigarettes/day) in comparison to their controls. CONCLUSIONS: The lack of association between smoking and CD has now been established in Jewish patients in Israel. The association was found in UC. The stronger genetic tendency in CD may contribute to this discrepancy.

The effects of short term lipid infusion on plasma and hepatic bile lipids in humans.

BACKGROUND: Patients on parenteral nutrition have an increased incidence of gall bladder sludge and gallstone disease, thought to be related to bile stasis. Intravenous lipid emulsions, especially those containing medium chain triglycerides, have also been shown to have a lithogenic effect on the composition of bile in the gall bladder. AIMS: To determine whether lipid infusion influences hepatic bile composition in patients with an indwelling T tube following cholecystectomy and choledochotomy. METHODS: In eight patients undergoing the above surgical procedure, the time at which effects of the interrupted enterohepatic circulation were minimal was determined. Twenty two cholesterol gallstone patients with bile fistula were then randomised to receive an infusion of a lipid emulsion containing either long chain triglycerides or a mixture of long and medium chain triglycerides. RESULTS: Lipid infusion resulted in a significant increase in plasma levels of triglycerides and phospholipids. Both lipid emulsions caused an increase in hepatic biliary cholesterol level and cholesterol saturation index, but this effect was more pronounced with medium chain triglycerides. The fatty acid composition of biliary phospholipids showed a significant enrichment of linoleic acid by both lipid infusions. CONCLUSIONS: Infusion of triglycerides causes lithogenic changes in hepatic bile composition in humans, the lithogenic effect of infusion of medium chain triglycerides being more pronounced than that of long chain triglycerides. This effect, coupled with gall bladder stasis, may be responsible for the increased risk of biliary sludge and gallstone formation in patients on long term lipid infusion.

The incorporation of fatty acids of different chain length into liver and biliary lipids in the perfused rat liver.

In an attempt to correlate the incorporation of fatty acids (FA) of different chain length into liver and biliary lipids, isolated rat livers were perfused for 2 h with Krebs-Ringer bicarbonate containing 1% albumin and 10 mumol of [1-14C]-labeled FA: C2, C8, C10, C12, C16, and C18:1. One to 1.36 mumol of medium-chain fatty acids (MCFA, C8, C10, and C12) and 6.6 mumol of long-chain FA (LCFA) were incorporated into liver lipids, 40% of the latter into phosphatidylcholine (PC). 14C-acetate (13 nmol) was incorporated into biliary cholesterol; 14C-MCFA contributed only 3.2-5 nmol; LCFA did not lead to newly synthesized cholesterol. Newly synthesized liver PC (2.75 to 3.25%) and newly synthesized liver cholesterol (6.5 to 10%) were secreted into bile. The specific radioactivity of biliary PC after infusion of all-saturated FA was 3.8-6.8 times higher than that of liver PC; for C18:1 it was only 1.7-fold. The specific radioactivity of biliary cholesterol, as compared to liver cholesterol, was 12 times higher for C2 and five times higher for MCFA. This indicates that a considerable proportion of the newly synthesized lipids was secreted into bile prior to significant mixing with preexisting liver PC and cholesterol pools. Liver PC contained 8% of unchanged 14C-C12; while 14C-C10 was not detected. Biliary PC, in contrast, contained 18% of unchanged 14C-C12 and 3% 14C-C10. These results suggest that after prolonged infusion of medium-chain triacylglycerols/long-chain triacylglycerols to patients, biliary PC may become enriched with MCTA. In addition, the oxidation of these FA may provide C-2 units which increase cholesterol synthesis.

Decreased fecal bile acid output in patients with coronary atherosclerosis.

In most patients with atherosclerosis, the underlying metabolic derangement remains undefined. Animal experiments have suggested that the ability to produce and excrete large amounts of bile acids may be an adaptation mechanism to cholesterol overload protecting against the atherogenic effects of cholesterol. However, there are very few data on bile acid excretion in human atherosclerosis. In the present study, we have investigated fecal bile acid secretion in subjects with and without coronary artery disease. The target group consisted of 30 patients with proven coronary artery disease and the control group consisted of 27 matched subjects without clinical or laboratory evidence of coronary atherosclerosis. Fecal bile acids were measured by gas-liquid chromatography from 24-hr stool collections under a controlled diet. The patients excreted significantly less bile acids than the controls (325+/-135 vs. 592+/-223 mg/day, respectively, p < 0.0001). The difference was primarily due to a reduced excretion of secondary bile acids. Less than 50% of deoxycholate was excreted by patients (180+/-81 mg/day) as compared to controls (367+/-168 mg/day, p < 0.0002), while lithocholic acid excretion was 111+/-62 mg/day in patients vs. 190 +/-70 mg/day in controls (p < 0.005). The fecal output of the two primary bile acids, cholic and chenodeoxycholic acid, did not differ significantly between patients and controls. The fecal output of total bile acids correlated with that of both secondary bile acids in patients as well as in controls. These findings suggest that patients with coronary heart disease are unable to excrete adequate amounts of bile acids to rid themselves of excess cholesterol, even if they are able to maintain a plasma cholesterol level comparable to that of healthy controls.

Preillness non dietary factors and habits in inflammatory bowel disease.

AIM: Environmental as well as genetic factors play a role in the pathogenesis of inflammatory bowel diseases. The effects of smoking and diet have been demonstrated. Other factors have not been extensively investigated. PATIENTS: Preillness non dietary habits and factors were studied in 88 patients with recent onset of inflammatory bowel diseases (55 with ulcerative colitis and 33 with Crohn's disease) and in matched 76 population and 68 clinic controls. RESULTS: No significant differences were found in relation to education, housing, birth weight, breast feeding in infancy and current weight. The current body mass index was significantly lower in patients as compared to clinic controls (p < 0.05). More patients had low levels of physical activity during the preillness period as compared to controls (p < 0.001 vs clinic controls), while more controls engaged in moderate (p < 0.05) or high levels of physical activity in the corresponding periods. Patients spent fewer hours in strenuous physical activity as compared to controls (NS). Patients slept fewer hours per day (p < 0.05 vs clinic controls). More patients than controls experienced stressful life events during the year prior to onset of symptoms (p < 0.05 for patients with Crohn's disease against both controls and all patients vs population controls). CONCLUSIONS: Other environmental factors besides smoking and diet may affect the pathogenesis of inflammatory bowel disease.

The effects of phospholipid molecular species on cholesterol crystallization in model biles: the influence of phospholipid head groups.

BACKGROUND/AIMS: Variations in the molecular species of biliary phospholipids have been shown to exert major effects on cholesterol solubility and carriers in model and human biles. The aim of this study was to explore systematically the effects of various phospholipid head groups on the cholesterol crystallization process in model biles. METHODS: Three different control model biles were prepared using varying proportions of egg lecithin, cholesterol and Na taurocholate. In the test biles, 20% of the egg lecithin was replaced with synthetic phosphatidylserine, phosphatidylethanolamine, phosphatidylglycerol or phosphatidylcholine, keeping the phospholipid acyl chains and other biliary lipids constant in each experiment. RESULTS: Phosphatidylserine and phosphatidylglycerol significantly prolonged the crystal observation time, from 2 days to 10 and 6 days, respectively (p<0.02), while phosphatidylethanolamine had little and phosphatidylcholine no effect. The crystal growth rate was significantly slowed down with 20% phospholipid replacement in the following order: phosphatidylglycerol >phosphatidylserine >phosphatidylethanolamine. The total crystal mass after 14 days, as measured by chemical analysis, was reduced by 59% with phosphatidylserine (p<0.05), and by 73% with phosphatidylglycerol (p<0.05); while phosphatidylethanolamine had little effect. The precipitable cholesterol crystal fractions after 14 days were significantly reduced with phosphatidylserine (54%) and phosphatidylglycerol (37%), but not with phosphatidylethanolamine or phosphatidylcholine. CONCLUSIONS: Variations in the head groups of biliary phospholipids may markedly slow down the cholesterol crystallization process in model biles.

Increased saturation of the fatty acids in the sn-2 position of phospholipids reduces cholesterol crystallization in model biles.

Changes in the molecular structure of biliary phospholipids were shown to have major effects on cholesterol solubility, carriers and crystallization in human and model biles. This study investigated systematically the effects of varying saturation of the phosphatidylcholine (PC) sn-2 fatty acid on the cholesterol crystallization process in 3 different model biles. Twenty % of the egg PC (EPC) in these biles were replaced by synthetic PC's with 16:0-18:0, 16:0-18:1, or 16:0-18:2 fatty acyl chains. With 18:0 in the sn-2 position, the crystal observation time (COT) was prolonged from 2 days in the control EPC solution to 14 days (p<0.05). The crystal growth rate (CGR) was reduced from 0.1 OD/day to unmeasurable levels, and the total crystal mass on day 14 decreased by 86%. The introduction of one (18:1), and two (18:2) double bonds in the sn-2 fatty acid rapidly reversed these effects. Ultracentrifugal analysis showed precipitable cholesterol as monohydrate crystals. In the 16:0-18:0 test solution, most of the precipitable cholesterol remained in the supersaturated multilamellar vesicles. Saturation of the biliary PC sn-2 fatty acyl chain prolongs the COT, slows the CGR, reduces the crystal mass, and extends cholesterol solubility in multilamellar vesicles. Desaturation of the sn-2 fatty acid reverses these effects.

Methotrexate in chronic active Crohn's disease: a double-blind, randomized, Israeli multicenter trial.

BACKGROUND: At present only one large controlled study has indicated that parenteral methotrexate may be effective in chronic active Crohn's disease (CD). AIM: To evaluate the effectiveness of oral methotrexate in chronic steroid-dependent CD. PATIENTS: Patients with active CD, who have received steroids and/or immunosuppressives for at least 4 months during the preceding 12 months and with a current Harvey-Bradshaw index of > or = 7 were studied. METHODS: Methotrexate (12.5 mg weekly) or 6-mercaptopurine (50 mg daily), or placebo were given during the 9 months of the trial in addition to steroids and 5-aminosalicylic acid as clinically indicated. RESULTS: Eighty-four patients were included (methotrexate, 26 patients; 6-mercaptopurine, 32 patients; placebo, 26 patients). The proportion of patients entering first remission as well as the proportions of patients relapsing after first remission were not significantly different between the groups. The mean Harvey-Bradshaw index and the mean monthly steroid dose were also similar. However, when each patient was evaluated as his or her own control, the reduction in steroid dose, the general well being, and the reduction in abdominal pain were significantly better in the methotrexate treated patients. CONCLUSIONS: Methotrexate at a weekly oral dose of 12.5 mg was found to be moderately better than 6-mercaptopurine and placebo in patients with chronic active CD.