The Amerindian's genes in the Mexican population are associated with development of gallstone disease

Association between HNF4A rs1800961 polymorphisms and gallstones in a Taiwanese population

BACKGROUND AND AIM

A large genetic effect of a novel gallstone-associated genetic variant, the hepatocyte nuclear factor 4α (HNF4A) rs1800961 polymorphism, has been identified through recent genome-wide association studies. However, this effect has not been validated in Asian populations. We investigated the association between the rs1800961 variant and gallstones among a Taiwanese population.

METHODS

A total of 20 405 participants aged between 30 and 70 years voluntarily enrolled in the Taiwan Biobank. Self-report questionnaires, physical examinations, biochemical tests, and genotyping were used for analysis. The association of the HNF4A rs1800961 variant and other metabolic risks with gallstone disease was analyzed using multiple logistic regression models.

RESULTS

The minor T allele of HNF4A rs1800961 was associated with an increased risk of gallstone, and the association remained significant even after adjustment for other risk factors including age, body mass index (BMI), diabetes, hyperlipidemia, hypertension, and cigarette smoking (adjusted odds ratio [OR] = 1.90, 95% confidence interval [CI] = 1.31 to 2.75) in male participants. When further stratified by BMI and age, the lithogenic effect was the most significant in male participants with obesity (adjusted OR = 3.55, 95% CI = 1.92 to 6.56) and who were younger (adjusted OR = 2.45, 95% CI = 1.49 to 4.04).

CONCLUSION

The novel gallstone-associated HNF4A rs1800961 variant was associated with the risk of gallstone in the Taiwanese men. Screening for the rs1800961 polymorphism may be particularly useful in assessing the risk of gallstone formation in younger or obese men.

Causal associations between changes in lipid profiles and risk of gallstone disease: a two-sample Mendelian randomization study

Background

Nonalcoholic fatty liver disease (NAFLD) has been linked to gallstone disease (GSD) in observational studies; however, the relationships between certain lipid profiles and GSD remain unclear.

Methods

We adopted a two-sample Mendelian randomization (MR) framework by applying different statistical methods to assess causalities between lipid profiles and GSD. We identified single-nucleotide polymorphisms (SNPs) for blood lipids and NAFLD from separate previous genome-wide association studies (GWASs).

Results

We retrieved GSD SNPs attributed to 10,520 cases and 361,194 controls and validated our estimates using GWAS summary data from UK Biobank. We also performed sex-stratified analyses. Based on the summary estimates of 41, 59, 35, and 2 SNPs for low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol (HDLC), triglycerides (TGs), and NAFLD, respectively, we found no evidence of a causal relationship between genetically-predicted lipid profiles and GSD. The odds ratios were 0.995 for LDLC [95% confidence interval (CI): 0.994-0.998] per 0.98 mmol/L, 0.999 for HDLC (95% CI: 0.996-1.003) per 0.41 mmol/L, 0.997 for TGs (95% CI: 0.994-1.001) per 1 mmol/L, and 0.993 for NAFLD (95% CI: 0.984-1.003). No evidence of associations between lipid profile s and GSD in validation MR analyses or the sex-stratification analyses was noted.

Conclusions

Genetically predicted hyperlipidemia or NAFLD is not causally associated with GSD.

Obesity and Gallstones

BACKGROUND

The prevalence of obesity has been increasing globally and represents the main risk factor for the development of gallstone disease (GD).

SUMMARY

Excess body weight represents the main cause for the development of GD; nevertheless, there have been described multiple risk factors for its development, among them modifiable risk factors as diet, lifestyle, physical inactivity, and non-modifiable risk factors as ethnicity, female sex, advanced age, parity, and genetic mutations. Body mass index, abdominal perimeter, and waist-hip index have been used to determine the degree of adiposity of a person. Hence, central abdominal fat has been mostly associated with insulin resistance with the consequent increase in the hepatic cholesterol secretion; contributing as one of the multiple mechanisms associated with the development of gallstones. This disease has a low mortality; however, it has been associated with multiple diseases such as cardiovascular diseases, carotid atherosclerosis, metabolic associated fatty liver disease, and gallbladder cancer, probably because they share many of the risk factors.

KEY MESSAGES

GD continues to be considered a disease with a high medical burden, in which it is sought to intervene in modifiable risk factors to reduce its development.

An overview on possible links between aflatoxin B1 exposure and gallbladder cancer

Gallbladder cancer (GBC) is one of the most common sites for biliary tract cancers. It has a worldwide distribution being endemic in South America and Southern Asia. These high GBC rates have previously been linked to the determinants of health such as nutrition, genetics, lifestyle, and environment. Exposure to aflatoxin B₁ (AFB₁), a human carcinogen, is suggested to be involved with GBC development. This work aims to analyse the interplay of social, lifestyle, and genetic predisposing factors to GBC. AFB₁ plays a pivotal role in carcinogenic onset by genetic and epigenetic modifications. AFB₁ can induce molecular changes involved in the GBC pathogenesis, such as overexpression of UCHL1 gene, mutagenesis of TP53 gene, abnormal expression of oncogenes BCL-2, and aberrantly methylation of ERBB family receptors. However, a large-scale scientific cooperation is needed to confirm these molecular links through which AFB₁ may increase the GBC risk. For that, monitoring AFB₁ exposure through AF-albumin and AFB1-lysine will clarify the level of exposure of the population to AFB₁ in the GBC hotspot. Further, analyses of AFB1-adduct concentrations in GBC cases (fatal and non-fatal) are needed to understanding if AF contamination can trigger gallbladder cancer.

Gallbladder Disorders: A Comprehensive Review

Gallbladder disorders encompass a wide breadth of diseases that vary in severity. We present a comprehensive review of literature for the clinical presentation, pathophysiology, diagnostic evaluation, and management of cholelithiasis-related disease, acute acalculous cholecystitis, functional gallbladder disorder, gallbladder polyps, gallbladder hydrops, porcelain gallbladder, and gallbladder cancer.

Gallstones

Gallstones grow inside the gallbladder or biliary tract. These stones can be asymptomatic or symptomatic; only gallstones with symptoms or complications are defined as gallstone disease. Based on their composition, gallstones are classified into cholesterol gallstones, which represent the predominant entity, and bilirubin ('pigment') stones. Black pigment stones can be caused by chronic haemolysis; brown pigment stones typically develop in obstructed and infected bile ducts. For treatment, localization of the gallstones in the biliary tract is more relevant than composition. Overall, up to 20% of adults develop gallstones and >20% of those develop symptoms or complications. Risk factors for gallstones are female sex, age, pregnancy, physical inactivity, obesity and overnutrition. Factors involved in metabolic syndrome increase the risk of developing gallstones and form the basis of primary prevention by lifestyle changes. Common mutations in the hepatic cholesterol transporter ABCG8 confer most of the genetic risk of developing gallstones, which accounts for ∼25% of the total risk. Diagnosis is mainly based on clinical symptoms, abdominal ultrasonography and liver biochemistry tests. Symptoms often precede the onset of the three common and potentially life-threatening complications of gallstones (acute cholecystitis, acute cholangitis and biliary pancreatitis). Although our knowledge on the genetics and pathophysiology of gallstones has expanded recently, current treatment algorithms remain predominantly invasive and are based on surgery. Hence, our future efforts should focus on novel preventive strategies to overcome the onset of gallstones in at-risk patients in particular, but also in the population in general.

Lipid trait-associated genetic variation is associated with gallstone disease in the diverse Third National Health and Nutrition Examination Survey (NHANES III)

BACKGROUND

Gallstone disease is one of the most common digestive disorders, affecting more than 30 million Americans. Previous twin studies suggest a heritability of 25% for gallstone formation. To date, one genome-wide association study (GWAS) has been performed in a population of European-descent. Several candidate gene studies have been performed in various populations, but most have been inconclusive. Given that gallstones consist of up to 80% cholesterol, we hypothesized that common genetic variants associated with high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) would also be associated with gallstone risk.

METHODS

To test this hypothesis, the Epidemiologic Architecture for Genes Linked to Environment (EAGLE) study as part of the Population Architecture using Genomics and Epidemiology (PAGE) study performed tests of association between 49 GWAS-identified lipid trait SNPs and gallstone disease in non-Hispanic whites (446 cases and 1,962 controls), non-Hispanic blacks (179 cases and 1,540 controls), and Mexican Americans (227 cases and 1,478 controls) ascertained for the population-based Third National Health and Nutrition Examination Survey (NHANES III).

RESULTS

At a liberal significance threshold of 0.05, five, four, and four SNP(s) were associated with disease risk in non-Hispanic whites, non-Hispanic blacks, and Mexican Americans, respectively. No one SNP was associated with gallstone disease risk in all three racial/ethnic groups. The most significant association was observed for ABCG5 rs6756629 in non-Hispanic whites [odds ratio (OR) = 1.89; 95% confidence interval (CI) = 1.44-2.49; p = 0.0001). ABCG5 rs6756629 is in strong linkage disequilibrium with rs11887534 (D19H), a variant previously associated with gallstone disease risk in populations of European-descent.

CONCLUSIONS

We replicated a previously associated variant for gallstone disease risk in non-Hispanic whites. Further discovery and fine-mapping efforts in diverse populations are needed to fully describe the genetic architecture of gallstone disease risk in humans.

Subtotal Cholecystectomy versus Total Cholecystectomy in Complicated Cholecystitis

Complicated cholecystitis can make dissections around the triangle of Calot difficult with a higher risk of duct and arterial injury. We reviewed a series of patients with cholecystitis receiving either partial or subtotal cholecystectomies and compared it with total cholecystectomies with respect to complications. A retrospective chart review was performed on all subtotal cholecystectomies performed for cholecystitis at University Medical Center of El Paso from June 2004 to December 2010. A similar number of patients who had total cholecystectomies for cholecystitis were selected as a comparison group from that same time period. A total of 116 patients who had subtotal and total cholecystectomies were reviewed (58 patients in each group). There were seven postoperative complications noted in the subtotal cholecystecomy (SC) group versus 14 for the total cholecystectomy (TC) group. Three patients in the SC group had cystic duct leaks, all successfully treated by endoscopic retrograde cholangiopancreatography with biliary stenting. There were two patients who had common bile duct injuries in the TC group and none in the SC group. Two patients had duodenal injuries in the TC group. Subtotal cholecystectomy is a viable alternative to total cholecystectomy in cases of complicated cholecystitis

Relationship between gallbladder surgery and ethnic admixture in African American and Hispanic American women

OBJECTIVES

The objective of this study was to investigate whether differences in admixture in African American and Hispanic American adult women are associated with differences in gallbladder surgery.

METHODS

Gallbladder surgery history on entry to the Women's Health Initiative's (WHI) study was used as a dichotomous outcome measure for this study. The proportion of European, sub-Saharan African, and Amerindian (AMI) admixture was estimated for 10,841 African American and 4,620 Hispanic American women in WHI using 92 ancestry informative markers. Logistic regression analyses assessed the relationship between admixture and gallbladder surgery in WHI women (enrollment at ages >50, mean age 61 years) with or without adjusting for multiple covariates, including measures of adiposity, parity, alcohol use, and education.

RESULTS

There was a significant positive association between AMI admixture and the frequency of gallbladder surgery in Hispanic Americans. The odds ratio (OR) and 95% confidence intervals (CIs) for AMI admixture group was OR=2.97, CI=2.01-4.38, P<10(-4). Although there were strong positive associations with parity and adiposity, and negative associations with alcohol consumption and education, accounting for these covariates did not remove the admixture association (OR=2.46, CI=1.62-3.73). In contrast, the effect of African admixture was nearly indistinguishable from that of the European admixture, both of which were protective in the Hispanic American group, and African admixture had a marginal association with decreased gallbladder surgery in the African American group. Measures of adiposity were associated with increased risk for gallbladder surgery and remained significant after accounting for admixture and each of the other covariates. Education level and alcohol use were associated with decreased risk for gallbladder disease. However, after accounting for the other covariates these variably remained significant.

CONCLUSIONS

AMI admixture is strongly associated with gallbladder surgery in women, even after adjustment for selected risk factors for cholelithiasis. Additional studies to ascertain the specific genetic risk factors underlying these associations are warranted.

Occurrence of pancreatic, biliary tract, and gallbladder cancers in Alaska Native people, 1973-2007

Objectives

To describe the occurrence of pancreatic, biliary tract, and gallbladder cancers within the Alaska Native (AN) population.

Study design

Population-based analysis utilizing a tumor registry and comparative population data.

Methods

Pancreaticobiliary cancers rates for AN people during 1973–2007 were determined from the Surveillance, Epidemiology, and End Results (SEER) AN Tumor Registry. Cancer incidence rates were age-adjusted to the World Standard Million and compared over 2 time periods with US white and black rates.

Results

During 1973–2007, 213 AN people developed pancreatic cancer, 73 gallbladder cancer and 61 biliary tract cancer. Pancreatic cancer occurs at similar rates in AN men and women, but data for 1993–2007 indicate that the rates among AN men may be increasing. The incidence rate in AN women (9.5/100,000) was statistically higher than in US white women (5.8/100,000). The incidence for biliary tract cancer in AN men and gallbladder cancer in AN men and women is statistically higher than that for US whites and blacks.

Conclusions

Pancreaticobiliary cancers, particularly biliary tract and gallbladder cancers, in both AN men and women and pancreatic cancer in women occur at an increased rate in AN people. Risk factors relating to the elevated rate are discussed. Certain factors are potentially modifiable, such as the use of tobacco and obesity.

Clinical characteristics and risk factors for symptomatic pediatric gallbladder disease

OBJECTIVE

Our center previously reported its experience with pediatric gallbladder disease and cholecystectomies from 1980 to 1996. We aimed to determine the current clinical characteristics and risk factors for symptomatic pediatric gallbladder disease and cholecystectomies and compare these findings with our historical series.

STUDY DESIGN

Retrospective, cross-sectional study of children, 0 to 18 years of age, who underwent a cholecystectomy from January 2005 to October 2008.

RESULTS

We evaluated 404 patients: 73% girls; 39% Hispanic and 35% white. The mean age was 13.10 ± 0.91 years. The primary indications for surgery in patients 3 years or older were symptomatic cholelithiasis (53%), obstructive disease (28%), and biliary dyskinesia (16%). The median BMI percentile was 89%; 39% were classified as obese. Of the patients with nonhemolytic gallstone disease, 35% were obese and 18% were severely obese; BMI percentile was 99% or higher. Gallstone disease was associated with hemolytic disease in 23% (73/324) of patients and with obesity in 39% (126/324). Logistic regression demonstrated older age (P = .019) and Hispanic ethnicity (P < .0001) as independent risk factors for nonhemolytic gallstone disease. Compared with our historical series, children undergoing cholecystectomy are more likely to be Hispanic (P = .003) and severely obese (P < .0279).

CONCLUSION

Obesity and Hispanic ethnicity are strongly correlated with symptomatic pediatric gallbladder disease. In comparison with our historical series, hemolytic disease is no longer the predominant risk factor for symptomatic gallstone disease in children.

Hepatic cholesterol transporter ABCG8 polymorphisms in gallstone disease in an Indian population

BACKGROUND AND AIM

Gallstone formation is characterized by the abnormal regulation of cholesterol trafficking and solubilization. The prevalence of gallstone disease (GSD) differs between ethnic groups sharing the common environment. These differences can be explained by a genetic predisposition to gallstone formation. Studies have identified single nucleotide polymorphisms (SNP) D19H and T400K in the cholesterol transporter gene ATP-binding cassette, subfamily G, member 8 (ABCG8) in patients with cholesterol gallstones. The aim of this study was to analyze the relationship between D19H and T400K polymorphisms in the ABCG8 gene and GSD in an Indian population, and the effects of these polymorphisms on cholesterol levels in sera and bile.

METHODS

A total of 226 patients with GSD were analyzed for their lipid profile in plasma and bile. A total of 289 controls were recruited, and their plasma lipid profile was analyzed by standard protocols. The genotype of SNP D19H and T400K of ABCG8 was analyzed in 226 patients and 222 control samples. SNP D19H was analyzed by direct sequencing, and SNP T400K genotyping was assayed by the amplification refractory mutation system-polymerase chain reaction.

RESULTS

There was no significant difference in the allelic distribution of SNP T400K between the GSD and gallstone-free groups (P > 0.05), but the distribution of the SNP variant, D19H, was significantly higher (P = 0.017, odds ratio = 2.274) in patients compared to controls. The analysis of serum and bile cholesterol followed a strong association with genotypes.

CONCLUSION

SNP D19H, but not SNP T400K, in the ABCG8 gene is significantly associated with GSD in an Indian population.

Prevalence and characteristics associated with self-reported gall bladder disease in Mexican American elders: results from the Hispanic Established Populations for Epidemiologic Studies in the Elderly (H-EPESE)

BACKGROUND AND AIMS

To identify the prevalence and characteristics of gall bladder disease (GBD) that has been self-reported in Mexican American Elders.

METHODS

A prospective survey of a regional probability sample of self-identified Mexican Americans aged 65 and over. The Hispanic Established Population for the Epidemiologic Studies of the Elderly (H-EPESE), a probability sample of non-institutionalized, Mexican Americans, aged 65 and over, residing in Southwestern states of Texas, New Mexico, Colorado, Arizona, and California. In 1993- 1994 (Wave 1), 3050 Mexican Americans, aged 65 and over, were selected at baseline as a weighted probability sample. In 1995-1996 (Wave 2), 2895 remained. Sample weights were used to extrapolate to the estimated 498,176 older Mexican Americans residing in the Southwest United States. Self-reported GBD was collected via in-home interviews.

RESULTS

The prevalence of self-reported GBD in Mexican American elders was found to be 18.8% with an average age of 75.05 years. The findings indicate that older Mexican Americans have an increased rate of GBD if they are female, have history of arthritis or hypertension and have more acculturation to the United States. However, the rate decreases when they score poorly on the Mini Mental State Exam. One major limitation was reliance on self-report, as GBD and other co-morbid illnesses may be under-, or overestimated.

CONCLUSIONS

Age is not protective in the prevalence of GBD in elder Mexican Americans. Persistent underlying genetics and dietary habits most likely attribute to this consistent high percentage, even in the elderly.

Routine liver biopsy to screen for nonalcoholic fatty liver disease (NAFLD) during cholecystectomy for gallstone disease: is it justified?

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and gallstone disease (GD) share common risk factors. There are no firm recommendations regarding screening of NAFLD in patients at risk. Our aim was to assess the prevalence of and factors associated with NAFLD in a cohort of patients operated for symptomatic GD and evaluate the usefulness of routine liver biopsy.

METHODS

Ninety-five consecutive patients underwent a liver biopsy at the end of a standard laparoscopic cholecystectomy for symptomatic GD. Clinical, biochemical, demographic, and anthropometric variables were obtained prospectively.

RESULTS

Fifty-two patients (55%) had biopsies compatible with NAFLD. These patients were classified according to the system proposed by Brunt et al. as follows: grade I, n = 27 (52%); grade II, n = 15 (29%); grade III, n = 10 (19%). Two grade III patients had zone III focal perisinusoidal fibrosis and three had overt cirrhosis. Only 13% of subjects had a suspected diagnosis of NAFLD preoperatively. In multivariate logistic regression, only obesity was significantly associated with NAFLD. There were no complications or mortality.

DISCUSSION

Fifty-five percent of patients with GD have associated NAFLD. Awareness of this association may result in an earlier diagnosis. The high prevalence of NAFLD in patients with GD may justify routine liver biopsy during cholecystectomy to establish the diagnosis, stage, and possible direct therapy.

Variation of the gene encoding the nuclear bile salt receptor FXR and gallstone susceptibility in mice and humans

BACKGROUND/AIMS

From quantitative trait locus mapping in inbred mice, we identified the Nr1h4 gene encoding the nuclear bile salt receptor FXR as a candidate gene for the cholesterol gallstone susceptibility locus Lith7. Here, we investigated further an association of the gene encoding FXR and gallstone susceptibility in mice and humans.

METHODS

The Nr1h4 gene was sequenced in inbred mouse strains with susceptible and resistant Lith7 alleles. Quantitative RT-PCR was employed to determine mRNA expression levels. Gallstone carriers and control subjects of three different populations comprising 1004 individuals were genotyped for polymorphisms of the orthologous human gene detected by sequencing.

RESULTS

Expression and sequence analyses in inbred mice were consistent with Nr1h4 underlying Lith7. In the human populations, we identified three frequent haplotypes that accounted for > 95% of all haplotypes observed. In a Mexican population, the most common haplotype NR1H4_1 was associated with gallstone prevalence. In contrast, NR1H4_1 displayed no association with gallstone prevalence in a German population, whereas in a Chilean population we observed a trend towards a protective effect of NR1H4_1.

CONCLUSIONS

Our study in an inbred mouse model and in three ethnically distinct populations indicates complex interactions of NR1H4 alleles and other risk factors for the development of cholelithiasis.

Evidence for common ancestral origin of a recurring BRCA1 genomic rearrangement identified in high-risk Hispanic families

BACKGROUND

Large rearrangements account for 8% to 15% of deleterious BRCA mutations, although none have been characterized previously in individuals of Mexican ancestry.

METHODS

DNA from 106 Hispanic patients without an identifiable BRCA mutation by exonic sequence analysis was subjected to multiplexed quantitative differential PCR. One case of Native American and African American ancestry was identified via multiplex ligation-dependent probe amplification. Long-range PCR was used to confirm deletion events and to clone and sequence genomic breakpoints. Splicing patterns were derived by sequencing cDNA from reverse transcription-PCR of lymphoblastoid cell line RNA. Haplotype analysis was conducted for recurrent mutations.

RESULTS

The same deletion of BRCA1 exons 9 through 12 was identified in five unrelated families. Long-range PCR and sequencing indicated a deletion event of 14.7 kb. A 3-primer PCR assay was designed based on the deletion breakpoints, identified within an AluSp element in intron 8 and an AluSx element in intron 12. Haplotype analysis confirmed common ancestry. Analysis of cDNA showed direct splicing of exons 8 to 13, resulting in a frameshift mutation and predicted truncation of the BRCA1 protein.

CONCLUSIONS

We identified and characterized a novel large BRCA1 deletion in five unrelated families-four of Mexican ancestry and one of African and Native American ancestry, suggesting the possibility of founder effect of Amerindian or Mestizo origin. This BRCA1 rearrangement was detected in 3.8% (4 of 106) of BRCA sequence-negative Hispanic families. An assay for this mutation should be considered for sequence-negative high-risk Hispanic patients.

Gallstone disease

Gallstone disease is one of the most prevalent gastrointestinal diseases with a substantial burden to health care systems that is supposed to increase in ageing populations at risk. Aetiology and pathogenesis of cholesterol gallstones still are not well defined, and strategies for prevention and efficient nonsurgical therapies are missing. This review summarizes current concepts on the pathogenesis of cholesterol gallstones with focus on the uptake and secretion of biliary lipids and special emphasis on recent studies into the genetic background.

Gallstone disease: Free radical reactions and the ambivalent role of bilirubin in the pathomechanism of gallstone formation

Az epekőbetegségek kialakulásában számos gén működését teszik felelőssé, melyek kapcsolatba hozhatók elsődlegesen a máj betegségeivel, az epeelfolyási és -képződési rendellenességekkel, a lipidmetabolizmus módosulásával, diabetes mellitussal, obesitassal, glutensensitiv enteropathiával, Crohn-betegséggel, Down-szindrómával, Gaucher-kórral, cysticus fibrosissal, valamint haematológiai kórképekkel és ileumresectiot követő állapottal. Kialakulásában szerepet játszanak gyógyszermellékhatások, bakteriális fertőzések, gyulladások, fémionterhelés és szabadgyökös reakciók. A zsírmájból az epébe telítetlen zsírsavak, lipidoxidok, diénkonjugátumok, és egyéb lipidperoxidációs termékek kerülnek, melyek az epevezetékben és a hólyagban primer és szekunder szabadgyökös folyamatokat indítanak el. Az epehólyagfalban lejátszódó gyulladásos folyamatok szabadgyöktermeléssel járnak. Az epe szabad bilirubin-tartalma koncentrációfüggően pro-, illetve antioxidánsként viselkedik. Az ambivalens tulajdonságú szabad bilirubin, amely a mikroszómák szivárgása révén, illetve a bél felől a baktériumok deglükorinidáló hatása következtében kimutatható mennyiségben van jelen az epehólyagban, a szabadgyökös reakciókat felerősíti. A szabad bilirubin kőalkotó reakciója az epében jelen lévő fémionokkal, elsődlegesen a Ca++-ionokal kalcium-(hidrogén)-bilirubinátot eredményez. A Ca++a zsírsavakkal is reakcióba lép, és ezzel megváltoztatja az epe viszkozitását. A lipidek, a szabad bilirubin és a fémionok együttesen kőalkotó komponensek. Az antioxidánsok, illetve azok derivátumai vagy hatásukban antioxidáns tulajdonságot fokozó vegyületek, készítmények több szinten is kedvezően befolyásolhatják az epe összetételét, illetve az epekőképződés gátlását.

A genomewide search finds major susceptibility loci for gallbladder disease on chromosome 1 in Mexican Americans

Gallbladder disease (GBD) is one of the major digestive diseases. Its risk factors include age, sex, obesity, type 2 diabetes, and metabolic syndrome (MS). The prevalence of GBD is high in minority populations, such as Native and Mexican Americans. Ethnic differences, familial aggregation of GBD, and the identification of susceptibility loci for gallstone disease by use of animal models suggest genetic influences on GBD. However, the major susceptibility loci for GBD in human populations have not been identified. Using ultrasound-based information on GBD occurrence and a 10-cM gene map, we performed multipoint variance-components analysis to localize susceptibility loci for GBD. Phenotypic and genotypic data from 715 individuals in 39 low-income Mexican American families participating in the San Antonio Family Diabetes/Gallbladder Study were used. Two GBD phenotypes were defined for the analyses: (1) clinical or symptomatic GBD, the cases of cholecystectomies due to stones confirmed by ultrasound, and (2) total GBD, the clinical GBD cases plus the stone carriers newly diagnosed by ultrasound. With use of the National Cholesterol Education Program/Adult Treatment Panel III criteria, five MS risk factors were defined: increased waist circumference, hypertriglyceredemia, low high-density lipoprotein cholesterol, hypertension, and high fasting glucose. The MS risk-factor score (range 0-5) for a given individual was used as a single, composite covariate in the genetic analyses. After accounting for the effects of age, sex, and MS risk-factor score, we found stronger linkage signals for the symptomatic GBD phenotype. The highest LOD scores (3.7 and 3.5) occurred on chromosome 1p between markers D1S1597 and D1S407 (1p36.21) and near marker D1S255 (1p34.3), respectively. Other genetic locations (chromosomes 2p, 3q, 4p, 8p, 9p, 10p, and 16q) across the genome exhibited some evidence of linkage (LOD >or=1.2) to symptomatic GBD. Some of these chromosomal regions corresponded with the genetic locations of Lith loci, which influence gallstone formation in mouse models. In conclusion, we found significant evidence of major genetic determinants of symptomatic GBD on chromosome 1p in Mexican Americans.

Mechanisms of disease: the genetic epidemiology of gallbladder stones

Cholelithiasis is one of the most prevalent and most expensive gastroenterologic diseases. It belongs to the group of complex metabolic disorders that affect humans, and its critical pathogenic mechanisms are not well defined. As a result, primary or secondary prevention strategies are sparse, and the only effective treatment is cholecystectomy. Here we provide an update on the molecular pathogenesis of gallbladder stones, evidence supporting the hypothesis that genetic factors are key elements predisposing to gallstones, and progress in human genetic studies of cholesterol stones. Data from recent identical twin, family and linkage studies provide conclusive evidence for a strong genetic component to gallstone disease. Furthermore, epidemiologic studies in at-risk populations indicate that gallstone formation is caused by multiple environmental influences and common genetic factors and their interactions. By contrast, monogenic subtypes of cholelithiasis, such as ATP-binding-cassette transporter deficiencies, appear to be rare. The summary of human association studies illustrates that distinct common gene variants might contribute to gallstone formation in different ethnic groups. The characterization of lithogenic genes in knockout and transgenic mice and the identification of many gallstone-susceptibility loci in inbred mice provide the basis for studies of the corresponding genes in patients with gallstones. The transfer of findings from mouse genetics to the bedside might lead to new strategies for individual risk assessment and reveal novel molecular targets for prevention and medical therapies.