Cholesterol cholelithiasis in two hamster models: Requirement for dietary cholesterol

Cholesterol cholelithiasis in two hamster models: Requirement for dietary cholesterol

A1028 AASLD ABSTRACTS GASTROENTEROLOGY, Vol. 108, No. 4 CHOLESTEROL CHOLELITHIASIS IN TWO HAMSTER MODELS: REQUIREMENT FOR DIETARY CHOLESTEROL. N Ay...

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A1028

AASLD ABSTRACTS

GASTROENTEROLOGY, Vol. 108, No. 4

CHOLESTEROL CHOLELITHIASIS IN TWO HAMSTER MODELS: REQUIREMENT FOR DIETARY CHOLESTEROL. N Ayyad, B.f Cohen, A. Ohshima, E.H. Mosbach. Dept. of Surgery, Beth Israel Med. Ctr., New York, NY. The effect of dietary fat and cholesterol (CH) on the incidence of CH gallstones (GS) has been studied in the hamster. Dam showed that hamsters fed an essential fatty acid deficient diet formed CH stones without exogenous CH. Our laboratory has found that hamsters fed a diet containing essential fatty acids readily formed stones only with exogenous CH. We examined cholesterol eholelithiasis in these two models in which the requirement for dietary cholesterol was different. Young male Sasco hamsters were fed the following diets for 6 weeks: gp 1, semipurified fat flee diet (SFF); gp 2, SFF + 0.3% CH; gp 3, semipurified diet containing essential fatty acids (2% corn oil) + 4% butterfat (SPD); gp 4, SPD + 0.3% CH. CH stones were present in 88% of the hamsters in gp 1; 0% formed stones in gp 3 while 75% formed stones in gp 4. Liver CH (LCH) was low in animals in gps 1-2 but was elevated when CH was added to the SPD (gp 3vs4). The fatty acids in biliary phospbolipids in gps 1-2 showed significantly lower linoleic acid (18:2) and higher oleie acid (18:1) levels compared to gps 3-4. The CH saturation index (CSI) of bile was 1.00 in gp 1, 0.67 in gp 3, and 1.40 in gp 4. The ratio of CDCA/CA was lower in gps 1-3 than gp 4. The % biliary CH was highest in gp 4. Gp 2 apparently absorbed little dietary CH while gp 4 absorbed significant amounts; this CH accumulated in the liver with additional CH appearing in the bile. Separation and analysis of CH carriers in bile showed that vesicles (yes) were present in gps 1,2,4; only mieelles were present in gp 3. In summary, in these models, CH vesicles are present in supersaturated bile regardless of the source of the biliary CH (endogenous vs dietary). _G2_

DIET

CHGS

CSI

%

BILE CH

~

LCH

mol %

%

mg/g

SFF

88

1.00

3.7

32

3.38

SFF + CH

96

0.95

3.8

61

3.49

SPD

0

0.67

2.4

0

7.16

SPD + CH

75

1.40

6.9

45

96.69

• ANTINEUTROPHIL C Y T O P L A S M I C A N T I B O D I E S ARE ABSENT IN U N A F F E C T E D R E L A T I V E S OF P A T I E N T S WITH P R I M A R Y SCLEROSING CHOLANGITIS AND ULCERATIVE COLITIS. DS Bansi 1, SK Lo 2, KA Fleming3, RW Chapmanl.Department of Gastroenterology 1 and Nuffield Department of Pathology and Bacteriology3, Oxford Radcliffe Hospital, Oxford UK. Liver Unit 2, King's College Hospital, London UK. Perinuclear antineutrophil cytoplasmic antibodies (ANCA) have been reported in 26-87% of patients with ulcerative colitis (UC) and primary sclerosing cholangitis (PSC). A prevalence of 18-30% has also been reported in unaffected first degree relatives, suggesting that this ANCA may be a genetic marker of disease susceptibility to both UC and PSC. AIM. To determine the prevalence of ANCA in unaffected first degree relatives of PSC and UC probands in a British population. M E T H O D . 36 UC (mean age 44 years, 12 males) and 34 PSC patients (mean age 50 years, 20 male) were studied. 27 PSC patients had coexisting UC, 2 had Crohn's colitis. In total, 21 UC (58%) and 22 PSC (65%) patients were ANCA positive. A total of 186 relatives were studied. Ninety six (29 male, mean age 39 years) and ninety (37 male, mean age 48 years) were from the PSC and UC probands respectively. As an environmental control, 32 spouses were also studied: 14 (5 males, mean age 52 years) were from the PSC group and 18 (9 males, mean age 40 years) were from the UC group. No relatives or controls had PSC or UC at the time of venesection. A further 18 healthy volunteers (9 males, mean age 39 years) acted as additional controls. ANCA was detected using the immunoalkaline phosphatase method. RESULTS. Only 2/96 (2%) of the PSC proband relatives tested positive for ANCA (one of these had systemic lupus erythematosus and the other had seropositive rheumatoid arthritis. Both conditions are known to exhibit ANCA). All other relatives and all control sera tested negative for the antibody. CONCLUSION. In the British population studied, ANCA was found only in subjects with PSC and UC and not in their healthy unaffected first degree relatives. It is therefore not a genetic marker for increased disease susceptibility to PSC or UC in this population.

A U T O A N T I B O D I E S A G A I N S T C A L R E T I C U L I N IN PATIENTS W I T H A U T O I M M U N E HEPATITIS. A. Bahler, W. Kreisel, C. Hellmann, P.A. Berg*, H.E. Blum, C. Snamer. Dept. of Gastroenterology, Medizinische Universit~itsklinik, D-79106, Freiburg, & *Medizinische Universit~itsklinik, D-72076, TObingen, Germany Calreticulin (CRT) is an endoplasmic reticulum resident protein belonging to the K D E L family. Among the multitude of suggested functions are e.g.: storage of Ca, Zn, Fe, protein-protein interactions and autogenicity. C R T shares amino acid sequence homology with e.g.." calnexin, the h u m a n collectin receptor (Clq-R), and the major antigens in onchocerciasis and schistosomiasis. High titers of anti-CRT immunoreactivity were found in a high proportion of sera from patients with SLE and Sj~Sgren's Syndrome. In this context we tested the sera of patients with autoimmune liver diseases for autoantibodies against calreficnlin. Methods: C R T was purified from human liver as described (BBRC (1993) 193, 611-616) and used as antigen. Sera of 67 healthy volunteers (control), 28 patients with autoimmune hepatitis (AIH), 17 patients with primary sclerosing cholangitis (PSC), 137 patients with primary biliary cirrhosis (PBC), and 15 patients with others than autoimmune liver diseases were analysed for autoantibodies to CRT by ELISA at serum dilutions up to 1:1000. Only titers exceeding a threefold SD of the m e a n control values at a serum dilution of 1:1000 were taken as positive. Results: A m o n g the 28 A I H sera 25 sera (~90%) were positive and revealed by far the highest anti-CRT titers of all the sera tested. 76 of 137 (55%) PBC sera, 7 of 17 (41%) of PSC sera, and 5 of 15 (33%) sera of patients with non-autoimmune liver diseases had positive antiC R T titers, but of considerably lower activity. Summary_ and Conclusions: Circulating autoantibodies against calreticulin could be detected in a high proportion of sera of patients with autoimmune hepatitis. Whether these autoantibodies could be involved in the pathogenesis of the disease or represent an epiphenomenon is unclear at present and merits further investigation.

ANTINEUTROPHIL CYTOPLASMIC ANTIBODY TITER BUT NOT lgG SUBCLASS DISTINGUISHES BETWEEN PRIMARY SCLEROSING CHOLANGITIS AND AUTOIMMUNE HEPATITIS. DS Bansi RW Chapman, KA Fleming. Department of Gastroenterology and Nuffield Department of Pathology and Bacteriology, Oxford Radcliffe Hospital, Oxford UK. Controversy exists about prevalence and specificity of perinuclear antineutrophil cytoplasmic antibodies (ANCA) in autoimmune liver disease. Thus, whether IgG subclass distinguishes between ANCA found in primary sclerosing cholangitis (PSC) and ulcerative colitis (UC) is unclear. Furthermore, the IgG subclass profile in autoimmune liver diseases has not been investigated. AIMS:.Determine (1) prevalence of ANCA in chronic liver disease (2).IgG subclass distribution of PSC and autoimmutae hepatitis (AIH) ANCA. METHODS: 278 sera were studied; 63 PSC (42 male, mean age 56); 28 AIH (5 male, mean age 60), 34 primary biliary cirrhosis (5 male, mean age 66), 12 alcoholic liver disease (9 male, mean age 63), 5 large duct obstruction (4 male, mean age 69), 4 haemachromatosis (3 male, mean age 58), 96 UC (44 male, mean age 53) and 36 normals (13 male, mean age 43). 20 AIH were on steroids. ANCA was detected using the alkaline phosphatase technique. IgG subclass distribution of 33 PSC and 11 AIH was determined using specific monoclonal antibodies, HP 6001 for IgG1, HP 6002 for IgG2, HP 6050 for IgG3 and SK 44 for IgG4 (Sigma Immunochemicals). RESULTS. PSC(n=63) AIH(n=28) PBC(n=34) UC(n=96) %ANCA at 1:5 65 50 6 45 %ANCA at 1:50 49 11 0 25 All other controls were ANCA negative at a serum dilution of l:5.The IgG subclass distribution was: lgG1 IgG2 IgG3 lgG4 PSC(n=33) 94% 15% 30% 12% AIH(n=ll) 82% 9% 27% 9% Four PSC and 4 AIH sera tested repeatedly over time showed no modification of ANCA IgG subclass distribution irrespective of disease activity. C O N C L U S I O N . Amongst the chronic liver diseases studied, ANCA was specific to the autoimmune liver diseases and titers were highest in PSC with a sensitivity of 49% and specificity of 91% at 1:50. Furthermore, PSC and AIH ANCA show a similar IgG subclass distribution (different from UC) and this may reflect similar mechanisms of immune regulation and possibly an identical antigenic species.