Genetic background of cholesterol 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.

Glutaredoxin 1 regulates cholesterol metabolism and gallstone formation by influencing protein S-glutathionylation

OBJECTIVE

Cholesterol gallstone disease (CGD) is closely related to cholesterol metabolic disorder. Glutaredoxin-1 (Glrx1) and Glrx1-related protein S-glutathionylation are increasingly being observed to drive various physiological and pathological processes, especially in metabolic diseases such as diabetes, obesity and fatty liver. However, Glrx1 has been minimally explored in cholesterol metabolism and gallstone disease.

METHODS

We first investigated whether Glrx1 plays a role in gallstone formation in lithogenic diet-fed mice using immunoblotting and quantitative real-time PCR. Then a whole-body Glrx1-deficient (Glrx1^-/-) mice and hepatic-specific Glrx1-overexpressing (AAV8-TBG-Glrx1) mice were generated, in which we analyzed the effects of Glrx1 on lipid metabolism upon LGD feeding. Quantitative proteomic analysis and immunoprecipitation (IP) of glutathionylated proteins were performed.

RESULTS

We found that protein S-glutathionylation was markedly decreased and the deglutathionylating enzyme Glrx1 was greatly increased in the liver of lithogenic diet-fed mice. Glrx1^-/- mice were protected from gallstone disease induced by a lithogenic diet because their biliary cholesterol and cholesterol saturation index (CSI) were reduced. Conversely, AAV8-TBG-Glrx1 mice showed greater gallstone progression with increased cholesterol secretion and CSI. Further studies showed that Glrx1-overexpressing greatly induced bile acid levels and/or composition to increase intestinal cholesterol absorption by upregulating Cyp8b1. In addition, liquid chromatography-mass spectrometry and IP analysis revealed that Glrx1 also affected the function of asialoglycoprotein receptor 1 (ASGR1) by mediating its deglutathionylation, thereby altering the expression of LXRα and controlling cholesterol secretion.

CONCLUSION

Our findings present novel roles of Glrx1 and Glrx1-regulated protein S-glutathionylation in gallstone formation through the targeting of cholesterol metabolism. Our data advises Glrx1 significantly increased gallstone formation by simultaneously increase bile-acid-dependent cholesterol absorption and ASGR1- LXRα-dependent cholesterol efflux. Our work suggests the potential effects of inhibiting Glrx1 activity to treat cholelithiasis.

Selected Aspects of the Intricate Background of Immune-Related Cholangiopathies-A Critical Overview

Primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are rare immune-related cholangiopathies with still poorly explained pathogenesis. Although triggers of chronic inflammation with subsequent fibrosis that affect cholangiocytes leading to obliteration of bile ducts and conversion to liver cirrhosis are unclear, both disorders are regarded to be multifactorial. Different factors can contribute to the development of hepatocellular injury in the course of progressive cholestasis, including (1) body accumulation of bile acids and their toxicity, (2) decreased food intake and nutrient absorption, (3) gut microbiota transformation, and (4) reorganized host metabolism. Growing evidence suggests that intestinal microbiome composition not only can be altered by liver dysfunction, but in turn, it actively impacts hepatic conditions. In this review, we highlight the role of key factors such as the gut-liver axis, intestinal barrier integrity, bile acid synthesis and circulation, and microbiome composition, which seem to be strongly related to PBC and PSC outcome. Emerging treatments and future therapeutic strategies are also presented.

The Antifungal Antibiotic Filipin as a Diagnostic Tool of Cholesterol Alterations in Lysosomal Storage Diseases and Neurodegenerative Disorders

Cholesterol is the most considerable member of a family of polycyclic compounds understood as sterols, and represents an amphipathic molecule, such as phospholipids, with the polar hydroxyl group located in position 3 and the rest of the molecule is completely hydrophobic. In cells, it is usually present as free, unesterified cholesterol, or as esterified cholesterol, in which the hydroxyl group binds to a carboxylic acid and thus generates an apolar molecule. Filipin is a naturally fluorescent antibiotic that exerts a primary antifungal effect with low antibacterial activity, interfering with the sterol stabilization of the phospholipid layers and favoring membrane leakage. This polyene macrolide antibiotic does not bind to esterified sterols, but only to non-esterified cholesterol, and it is commonly used as a marker to label and quantify free cholesterol in cells and tissues. Several lines of evidence have indicated that filipin staining could be a good diagnostic tool for the cholesterol alterations present in neurodegenerative (e.g., Alzheimer's Disease and Huntington Disease) and lysosomal storage diseases (e.g., Niemann Pick type C Disease and GM1 gangliosidosis). Here, we have discussed the uses and applications of this fluorescent molecule in lipid storage diseases and neurodegenerative disorders, exploring not only the diagnostic strength of filipin staining, but also its limitations, which over the years have led to the development of new diagnostic tools to combine with filipin approach.

Are laparoscopic cholecystectomy and natural orifice transluminal endoscopic surgery gallbladder preserving cholecystolithotomy truly comparable? A propensity matched study

BACKGROUND

Cholecystectomy is the preferred treatment option for symptomatic gallstones. However, another option is gallbladder-preserving cholecystolithotomy which preserves the normal physiological functions of the gallbladder in patients desiring to avoid surgical resection.

AIM

To compare the feasibility, safety and effectiveness of pure natural orifice transluminal endoscopic surgery (NOTES) gallbladder-preserving cholecystolithotomy vs laparoscopic cholecystectomy (LC) for symptomatic gallstones.

METHODS

We adopted propensity score matching (1:1) to compare trans-rectal NOTES cholecystolithotomy and LC patients with symptomatic gallstones. We reviewed 2511 patients with symptomatic gallstones from December 2017 to December 2020; 517 patients met the matching criteria (NOTES, 110; LC, 407), yielding 86 pairs.

RESULTS

The technical success rate for the NOTES group was 98.9% vs 100% for the LC group. The median procedure time was 119 min [interquartile ranges (IQRs), 95-175] with NOTES vs 60 min (IQRs, 48-90) with LC (P < 0.001). The frequency of post-operative pain was similar between NOTES and LC: 4.7% (4/85) vs 5.8% (5/95) (P = 0.740). The median duration of post-procedure fasting with NOTES was 1 d (IQRs, 1-2) vs 2 d with LC (IQRs, 1-3) (P < 0.001). The median post-operative hospital stay for NOTES was 4 d (IQRs, 3-6) vs 4 d for LC (IQRs, 3-5), (P = 0.092). During follow-up, diarrhea was significantly less with NOTES (5.8%) compared to LC (18.6%) (P = 0.011). Gallstones and cholecystitis recurrence within a median of 12 mo (range: 6-40 mo) following NOTES was 10.5% and 3.5%, respectively. Concerns regarding the presence of abdominal wall scars were present in 17.4% (n = 15/86) of patients following LC (mainly women).

CONCLUSION

NOTES provides a feasible new alternative scar-free treatment for patients who are unwilling or unable to undergo cholecystectomy. This minimally invasive organ-sparing procedure both removes the gallstones and preserves the physiological function of the gallbladder. Reducing gallstone recurrence is essential to achieving widespread clinical adoption of NOTES.

A Mitochondrial DNA Variant Elevates the Risk of Gallstone Disease by Altering Mitochondrial Function

BACKGROUND AND AIMS

Gallstone disease (cholelithiasis) is a cholesterol-related metabolic disorders with strong familial predisposition. Mitochondrial DNA (mtDNA) variants accumulated during human evolution are associated with some metabolic disorders related to modified mitochondrial function. The mechanistic links between mtDNA variants and gallstone formation need further exploration.

METHODS

In this study, we explored the possible associations of mtDNA variants with gallstone disease by comparing 104 probands and 300 controls in a Chinese population. We constructed corresponding cybrids using trans-mitochondrial technology to investigate the underlying mechanisms of these associations. Mitochondrial respiratory chain complex activity and function and cholesterol metabolism were assessed in the trans-mitochondrial cell models.

RESULTS

Here, we found a significant association of mtDNA 827A>G with an increased risk of familial gallstone disease in a Chinese population (odds ratio [OR]: 4.5, 95% confidence interval [CI]: 2.1-9.4, P=1.2×10-4). Compared with 827A cybrids (haplogroups B4a and B4c), 827G cybrids (haplogroups B4b and B4d) had impaired mitochondrial respiratory chain complex activity and function and activated JNK and AMPK signaling pathways. Additionally, the 827G cybrids showed disturbances in cholesterol transport and accelerated development of gallstones. Specifically, cholesterol transport through the transporter ABCG5/8 was increased via activation of the AMPK signaling pathway in 827G cybrids.

CONCLUSIONS

Our findings reveal that mtDNA 827A>G induces aberrant mitochondrial function and abnormal cholesterol transport, resulting in increased occurrence of gallstones. The results provide an important biological basis for the clinical diagnosis and prevention of gallstone disease in the future.

The Impact of Egg Nutrient Composition and Its Consumption on Cholesterol Homeostasis

Nutrient deficiencies and excess are involved in many aspects of human health. As a source of essential nutrients, eggs have been used worldwide to support the nutritional needs of human societies. On the other hand, eggs also contain a significant amount of cholesterol, a lipid molecule that has been associated with the development of cardiovascular diseases. Whether the increase of egg consumption will lead to elevated cholesterol absorption and disruption of cholesterol homeostasis has been a concern of debate for a while. Cholesterol homeostasis is regulated through its dietary intake, endogenous biosynthesis, utilization, and excretion. Recently, some research interests have been paid to the effects of egg consumption on cholesterol homeostasis through the intestinal cholesterol absorption. Nutrient components in eggs such as phospholipids may contribute to this process. The goals of this review are to summarize the recent progress in this area and to discuss some potential benefits of egg consumption.

Proteasome inhibition protects against diet-induced gallstone formation through modulation of cholesterol and bile acid homeostasis

Gallstone disease is one of the most prevalent and costly gastrointestinal disorders worldwide. Gallstones are formed in the biliary system by cholesterol secretions in bile, which result from excess cholesterol, a deficiency in bile salts or a combination of the two. The present study examined the effects of proteasome inhibition on gallstone formation using the proteasome inhibitors bortezomib (BT) and carfilzomib (CF). C57BL/6J mice were fed a lithogenic diet to generate gallstones and injected with BT or CF for 12 weeks. After 12 weeks of the lithogenic diet, 8 out of the 10 mice in the control group had developed gallstones, whereas none of the mice who received proteasome inhibitors had developed gallstones. Notably, the expression of genes associated with cholesterol synthesis (sterol regulatory element‑binding protein‑2 and 3‑hydroxy‑3‑methylglutaryl‑CoA reductase), cholesterol secretion [ATP‑binding cassette subfamily G member 5 (ABCG5) and ABCG8] and bile acid synthesis [cytochrome P450 family 7 subfamily A member 1 (Cyp7a1), Cyp7b1, Cyp27a1 and Cyp8b1] was reduced in the livers of mice injected with BT or CF. Cyp7a1 encodes cholesterol 7α‑hydroxylase, the rate‑limiting enzyme in the synthesis of bile acid from cholesterol. The present study therefore measured the expression levels of transcription factors that are known to inhibit Cyp7a1 expression, namely farnesoid X receptor (FXR), pregnane X receptor (PXR) and small heterodimer partner (SHP). Although FXR, PXR and SHP expression was predicted to increase in the presence of proteasome inhibitors, the expression levels were actually reduced; thus, it was concluded that they were not involved in the proteasome inhibition‑induced regulation of Cyp7a1. Further investigation of the mitogen‑activated protein kinase and protein kinase A (PKA) signaling pathways in human hepatoma cells revealed that proteasome inhibition‑induced c‑Jun N‑terminal kinase (JNK) phosphorylation reduced CYP7A1 and CYP27A1 expression. In addition, reduced PKA phosphorylation as a result of proteasome inhibition regulated ABCG5 and ABCG8 expression. In conclusion, these findings suggest that proteasome inhibition regulates cholesterol and biliary metabolism via the JNK and PKA pathways, and is a promising therapeutic strategy to prevent gallstone disease.

Combined microstructural and mineralogical phase characterization of gallstones in a patient-based study in SW Spain - Implications for environmental contamination in their formation

This study explores the environmental impact of metal exposure on humans through detailed phase and structural characterization of gallstones from two environmentally contrasting populations in Huelva Province (SW Spain). A total of 42 gallstone samples, obtained after surgical intervention at the Riotinto Hospital, were studied by powder X-ray diffraction (XRD), Fourier Transformed Infra-Red spectroscopy (FTIR), FTIR-μ-ATR (Attenuated Total Reflection) coupled with an optical microscope, and by Environmental Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy (ESEM-EDS), and subsequently classified according to their phase composition and structure. Additionally, the patients were enquired for their living habits in order to analyze the source of possible exposure to metal contamination. The gallstones were classified into pure, mixed and composite cholesterol stones, black and brown pigment stones, and carbonate stones. The patients from the study group residing in a region with acknowledged metal contamination of both natural and anthropogenic origin have a higher risk of metal exposure through contaminated soil, particle matter in the air, and consumption of local water and food products. According to our findings, the metal exposure is related to a higher tendency of forming black pigment stones in the study group in comparison to the control group residing in a natural park with nearly pristine environmental conditions. Moreover, the gallstones from the study group showed to contain more abundant metal components, such as Cu, Fe, Ni, and Zn, than those from the control group. To our knowledge this is the first study to examine the regional environmental impact of metal exposure on human gallstones.

Non-alcoholic fatty liver disease associated with gallstones in females rather than males: a longitudinal cohort study in Chinese urban population

Background

Whether non-alcoholic fatty liver disease (NAFLD) is a risk factor for gallstones remains uncertain. Few longitudinal or cohort studies have been used to identify this relationship. The aim of this study was to confirm the association between NAFLD and gallstones in a longitudinal cohort of urban dwellers in China.

Methods

To elucidate the association between NAFLD and gallstones, we fitted a generalized estimating equation (GEE) model in a large-scale longitudinal cohort over 6 years, which included 11,200 participants with at least three regular health check-ups.

Results

A total of 498 cases of gallstones occurred during the 6-year follow-up, which resulted in a total incidence density of 12.73 per 1000 person-years (498/39, 135.5 person-years). The GEE analyses confirmed and clarified the association between NAFLD and gallstones (relative risk (RR) = 1.2381, 95% confidence interval (CI) = 1.003–1.528, P = 0.047) after adjusting for other potential confounding factors, especially in females (RR = 1.707, 95% CI = 1.245–2.341, P = 0.001).

Conclusions

NAFLD is associated with gallstones in an urban Chinese population from the middle to upper socioeconomic strata. Moreover, this association is more strongly apparent in females than in males. Further cohort studies must be conducted to confirm this association in the general population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-014-0213-y) contains supplementary material, which is available to authorized users.

Cytoprotective propensity of Bacopa monniera against hydrogen peroxide induced oxidative damage in neuronal and lung epithelial cells

Hydrogen peroxide (H2O2), a major reactive oxygen species (ROS) produced during oxidative stress, is toxic to the cells. Hence, H2O2 has been extensively used to study the effects of antioxidant and cytoprotective role of phytochemicals. In the present investigation H2O2 was used to induce oxidative stress via ROS production within PC12 and L132 cells. Cytoprotective propensity of Bacopa monniera extract (BME) was confirmed by cell viability assays, ROS estimation, lipid peroxidation, mitochondria membrane potential assay, comet assay followed by gene expression studies of antioxidant enzymes in PC12 and L132 cells treated with H2O2 for 24 h with or without BME pre-treatment. Our results elucidate that BME possesses radical scavenging activity by scavenging 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), superoxide radical, and nitric oxide radicals. The IC50 value of BME against these radicals was found to be 226.19, 15.17, 30.07, and 34.55 µg/ml, respectively). The IC50 of BME against ROS, lipid peroxidation and protein carbonylation was found to be 1296.53, 753.22, and 589.04 µg/ml in brain and 1137.08, 1079.65, and 11101.25 µg/ml in lung tissues, respectively. Further cytoprotective potency of the BME ameliorated the mitochondrial and plasma membrane damage induced by H2O2 as evidenced by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase leakage assays in both PC12 and L132 cells. H2O2 induced cellular, nuclear and mitochondrial membrane damage was restored by BME pre-treatment. H2O2 induced depleted antioxidant status was also replenished by BME pre-treatment. This was confirmed by spectrophotometric analysis, semi-quantitative RT-PCR and western blot studies. These results justify the traditional usage of BME based on its promising antioxidant and cytoprotective property.

Single nucleotide polymorphism rs3732860 in the 3'-untranslated region of CYP8B1 gene is associated with gallstone disease in Han Chinese

BACKGROUND AND AIMS

Gallstone disease (GD) is a common disease of multigenetic origin; however, the major susceptibility loci for GD in human populations remain unidentified. This study aimed to identify the genetic factors contributing to gallstone development in Chinese.

METHODS

A genome-wide scan was conducted in 12 Han Chinese GD families to identify linkage loci. The linkage region showing the highest logarithm of odds score encompasses the sterol 12α-hydroxylase gene (CYP8B1). Replication analysis with an independent sample of 192 GD patients and 192 unrelated, matched controls was carried out to verify the associations between CYP8B1 polymorphisms and GD.

RESULTS

Three loci (D3S1266, D4S406, and D9S1682) showed suggestive or nominal evidence of linkage in all 12 GD families. The logarithm of odds score of D3S1266 reached 2.71 in the families with late-onset patients. The single nucleotide polymorphism rs3732860 in the 3'-untranslated region of CYP8B1 showed significant association to GD (P = 0.022), and carriers of the A allele had lower risk of GD (odds ratio = 1.46, 95% confidence interval: 1.055-2.034) compared with carriers of the G allele.

CONCLUSIONS

The single nucleotide polymorphism rs3732860 in the 3'-untranslated region of the CYP8B1 gene is associated with risk of GD in Chinese Han and appears to be responsible for the observed linkage with D3S1266.

Mucin genes in gallstone disease

Gallstone disease is a complex disorder that can be caused by environmental influences, common genetic factors and their interactions. Three major pathogenic abnormalities are considered to involve in gallstone formation: cholesterol supersaturation in bile, precipitation and nucleation of excess cholesterol, and gallbladder hypomotility, while, mucin takes part in the cholesterol nucleation process. Up to date, more than 20 mucin genes have been reported, 9 of them are identified at the mRNA and/or protein level in native gallbladder and its associated diseases. In the gallbladder, mucin is essential for best protection against detergent effect of high concentration of bile acids. Over the past decade, the properties, expressions and functions of the gallbladder mucins are delineated in animal and human studies. Alteration expressions of mucins are thought to response during the pathogenesis of gallstone formation. Moreover, recent genetic association study demonstrated mucin gene polymorphisms may also influence susceptibility to gallstone disease. This review is not to provide a complete coverage of all the aspects of mucin glycoproteins, but focus on the role and expression of mucins involve in the regulation of cholelithogenesis.

Cholelithiasis and its complications in children and adolescents: update and case discussion

In recent years, gallbladder disease, primarily in the form of cholelithiasis, has been on the rise among infants and children. Although pediatric gallbladder disease is still less prevalent than adult gallbladder disease, physicians and other clinicians who care for children need to be aware of this underappreciated problem and understand the manifestations of biliary disease in the pediatric population. In this article, case discussions will serve as a platform for discussing the clinical spectrum of cholelithiasis and its complications in children as well as discussing the latest evidence related to diagnosis and treatment.

PIXE ANALYSIS OF GALLSTONES

Particle Induced X-ray Emission (PIXE) technique has been used to determine the trace elements present in fourteen representative human gallstone samples collected from eastern region (Orissa) and thirteen representative samples collected from southern region (Chennai) of India. PIXE irradiation of the samples has been carried out by using the 3 MV tandem type horizontal pelletron accelerator facility at Institute of Physics, Bhubaneswar with proton beam of energy 3 MeV. In the present investigation, twenty one trace elements like S , Cl , K , Ca , Ti , V , Cr , Mn , Fe , Ni , Cu , Zn , As , Se , Br , Rb , Sr , Y , Zr , Mo and Pb have been estimated in all the three types of gallstones viz. cholesterol stone, mixed stone and pigment stone. While sulphur in cholesterol stones in the eastern region was less than that of the southern region, sulphur was present as a minor element in the pigment stones of both the regions. Less concentration of copper in the gallstones from eastern region is another interesting observation. The lower values of copper in the patients of eastern region may be due to different types of food habits. The concentrations of all the elements in the southern region pigment stones have higher values than that of the eastern region. Moreover, the concentrations of Fe and Mo in cholesterol stone and pigment stone samples in southern region have also higher values than in eastern region. The current PIXE study is of its first kind in this eastern region of India.

Polymorphism at the mucin-like protocadherin gene influences susceptibility to gallstone disease

BACKGROUND

Gallstone disease (GSD) is a common disease that can be caused by environmental influences, common genetic factors and their interactions. Mucin glycoproteins may be one important factor for GSD. We conducted a case-control study to investigate the relationship between the mucin-like protocadherin (MUPCDH) gene polymorphisms and GSD.

METHODS

The study included 452 GSD cases and 491 healthy controls who had no evidence of gallstones by ultrasound examination. Two common tagging single nucleotide polymorphism (SNP) rs3758650 and rs7932167, and four non-synonymous SNPs rs34362213, rs2740375, rs7108757 and rs2740379 were genotyped. The genetic effects were evaluated using the multivariate regression model.

RESULTS

The genotypes of these SNPs were all in Hardy-Weinberg equilibrium. Three non-synonymous SNPs (rs34362213, rs7108757 and rs2740379) were monomorphic. The single SNP analysis showed two SNPs (rs7932167 and rs2740375) were not associated with GSD and only SNP rs3758650 had the association of the presence of GSD with an odds ratio (OR) of 1.59 (adjusted P=0.013) for the AG genotype and 5.82 (adjusted P=0.007) for the AA genotype when compared with the reference GG genotype. The haplotype analysis of the three polymorphic SNPs showed GCA was significant for GSD (adjusted p=0.001) with an odds ratio (OR) of 1.41 when compared to other haplotypes.

CONCLUSIONS

The MUPCDH genetic polymorphism rs3758650 was considered a genetic marker to predict symptomatic GSD subjects. It may be of importance for GSD patients with the risk SNPs to be frequently checked because they may develop symptomatic GSD.

Network screening of Goto-Kakizaki rat liver microarray data during diabetic progression

Background

Type 2 diabetes mellitus (T2DM) is a complex systemic disease, with significant disorders of metabolism. The liver, a central energy metabolic organ, plays a critical role in the development of diabetes. Although gene expression levels are able to be measured via microarray since 1996, it is difficult to evaluate the contributions of one altered gene expression to a specific disease. One of the reasons is that a whole network picture responsible for a specific phase of diabetes is missing, while a single gene has to be put into a network picture to evaluate its importance. In the aim of identifying significant transcriptional regulatory networks in the liver contributing to diabetes, we have performed comprehensive active regulatory network survey by network screening in 4 weeks (w), 8-12 w, and 18-20 w Goto-Kakizaki (GK) rat liver microarray data.

Results

We identify active regulatory networks in GK rat by network screening in the following procedure. First, the regulatory networks are compiled by using the known binary relationships between the transcriptional factors and their regulated genes and the biological classification scheme, and second, the consistency of each regulatory network with the microarray data measured in GK rat is estimated to detect the active networks under the corresponding conditions. The comprehensive survey of the consistency between the networks and the measured data by the network screening approach in the case of non-insulin dependent diabetes in the GK rat reveals: 1. More pathways are active during inter-middle stage diabetes; 2. Inflammation, hypoxia, increased apoptosis, decreased proliferation, and altered metabolism are characteristics and display as early as 4weeks in GK strain; 3. Diabetes progression accompanies insults and compensations; 4. Nuclear receptors work in concert to maintain normal glycemic robustness system.

Conclusion

Notably this is the first comprehensive network screening study of non-insulin dependent diabetes in the GK rat based on high throughput data of the liver. Several important pathways have been revealed playing critical roles in the diabetes progression. Our findings also implicate that network screening is able to help us understand complex disease such as diabetes, and demonstrate the power of network systems biology approach to elucidate the essential mechanisms which would escape conventional single gene-based analysis.

The prevalence and risk factors for gallstone disease

Gallstone disease is one of the most prevalent gastrointestinal disorders. In addition, the costs associated with the diagnosis and treatment of gallstone disease have been rapidly increasing. The etiology and pathogenesis of gallstone disease remains incompletely understood. Gallstone formation may result from a complex interaction of genetic and environmental factors. This article reviews the prevalence and risk factors associated with gallstone disease. Understanding the pathogenesis of gallstone disease could lead to the development of better therapeutic and preventive strategies for dealing with this disease.

Significant association of ABCG5 604Q and ABCG8 D19H polymorphisms with gallstone disease

BACKGROUND

Adenosine triphosphate-binding cassette (ABC) transporters ABCG5 and ABCG8 are sterol export pumps regulating biliary cholesterol excretion. The formation of gallstones, supersaturated with cholesterol in bile, is determined by genetic and environmental factors. The interaction of susceptible gene polymorphisms with age, sex and body mass index in gallstone disease is unclear.

METHODS

In a cross-sectional study, 979 subjects (880 men and 99 women, mean(s.d.) age 47.7(10.4) years) were recruited from a hospital-based population. Of these, 74 were diagnosed with gallstone disease by abdominal ultrasonography. Five non-synonymous polymorphisms, E604Q (ABCG5), D19H, C54Y, T400K and A632V (ABCG8), were analysed using the TaqMan genotyping assay.

RESULTS

The serum total cholesterol and both low- and high-density lipoprotein cholesterol levels were significantly lower in subjects with gallstones than in those without. 604Q (CC) and D19H (GC) genotypes were significantly associated with gallstone disease, even when adjusted for age, sex and body mass index. The genetic risk of developing gallstone disease was further stratified by age. The risk was greatly increased in subjects younger than 50 years with the D19H genotype and those of 50 years or more with the 604Q genotype.

CONCLUSION

Carriers of ABCG5 604Q or ABCG8 D19H polymorphisms have an increased risk of gallstone disease independent of age, sex and body mass index.

Gallstone analysis using Fourier transform infrared spectroscopy (FT-IR)

BACKGROUND

Gallstone analysis is important in determining the possible etiology of stone formation and the pathophysiology of cholelithiasis. Physical analysis using Fourier transform infrared spectroscopy (FT-IR), compared to chemical analysis, requires minimal sample volume, shows uniform sensitivity and specificity for all components and provides quantitative results with greater reproducibility. We studied the characteristics and distribution of gallstones using FT-IR in addition to the risk factors for gallstone formation in Korean patients. A better understanding of the mechanism underlying stone formation may help prevent gallstone development.

METHODS

Physical analysis of gallstones in 490 patients who underwent cholecystectomy was carried out using the FT-IR system 2000 (Perkin-Elmer Co.) and Spectrum software (Perkin-Elmer Co.). Visual inspection of the size, color, consistency and surface of the stones was compared with the physical characteristics. Clinical, demographic and laboratory findings were evaluated and compared with the gallstone components.

RESULTS

The FT-IR evaluation showed that most gallstones were composed of a single component (84.1%); cholesterol was the most commonly observed element among the major components (50%, 245/490). Morphological classification according to color, consistency and surface was different from the FT-IR composition analysis. There were significant differences in the components based on age, obesity, education level and the presence of diabetes mellitus.

CONCLUSIONS

The results of this study show that physical analysis of gallstones with FT-IR provides important information on stone composition, distribution and risk factors. These study results will help improve our understanding of the pathophysiology of gallstone disease in the Korean population, where there is a high frequency of hepatobiliary disorders.

Haplotype analysis of signal peptide (insertion/deletion) and XbaI polymorphisms of the APOB gene in gallbladder cancer

PURPOSE

The incidence of gallbladder cancer (GBC) is usually paralleled by the prevalence of gallstone disease, and genes of cholesterol metabolism have been implicated in gallstone disease. The XbaI and insertion/deletion (ins/del) polymorphism of Apolipoprotein B (APOB) appears to influence cholesterol homoeostasis and possibly risk for gallstone disease. We examined the effect of these polymorphisms individually as well as their haplotypes on GBC and gallstone patients in North Indian population.

METHODS

The study comprises 123 consecutive cases of proven GBC, 172 cases of gallstone and 232 healthy subjects of similar age and sex. The genomic DNA was extracted from peripheral blood leucocytes and genotyping was performed using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism.

RESULTS

In a case-control study, APOB XbaI and ins/del polymorphisms were not significantly associated with risk of GBC. Using the expectation maximization algorithm, four haplotypes were obtained, and haplotype X(+),D was found to be significantly higher in GBC patients without stone in comparison with healthy subjects [odds ratio (OR) 2.9, 95% confidence interval 1.2-6.6 P=0.012].

CONCLUSIONS

The X(+),D haplotype of APOB is associated with increased risk for development of GBC and the risk is not modified in the presence of gallstones.

Steroid hormones polymorphisms and cholelithiasis in Greek population

BACKGROUND

Genetic variation in genes involved in steroid biosynthesis, metabolism and signal transduction have been suggested to play a role in gallstone disease.

METHODS

To elucidate the possible role of genetic variation in the estrogen receptors alpha and beta (ER-alpha, ER-beta) and androgen receptor (AR) genes in breast cancer risk, the -1174(TA)n, c.1092+3607(CA)(n) and c.172(CAG)n repeat polymorphisms of the three genes were studied. A case-control cohort of 99 patients with cholelithiasis and 179 controls were used.

RESULTS

No significant difference was observed in the frequency distribution of -1174(TA)(0-26) in the ER-alpha gene between patients and controls, while a significant difference was observed in the frequency distribution of repeat polymorphism c.1092+3607(CA)5-27 and c.172(CAG)5-32 in the ER-beta gene and AR gene, respectively (P< or =0.001 and P=0.05, respectively). A significant difference was observed in the repeat genotype distribution (SS, SL, LL) in the (CA)n of the ER-beta gene (P<0.0001) and in the (CAG)n of the AR gene (P< or =0.0001). A significantly decreased odds ratio for cholelithiasis risk was observed in individuals having the SL and LL genotype for ER-beta gene compared with SS genotype (OR=0.212; 95% CI 0.105-0.426; P<0.0001 and OR=0.042; 95% CI 0.018-0.097, respectively) and LL genotype for AR gene (OR=0.622; 95% CI 0.345-1.121; P=0.114 and OR=0.287; 95% CI 0.151-0.543, P<0.0001, respectively). This protective effect of SL and LL genotypes for ER-beta and LL for AR gene remained evident (P<0.0001 for all of them) even after adjustment for various risk factors.

CONCLUSIONS

In conclusion an association for cholelithiasis risk between short alleles for both c.1092+3607(CA)5-27 and c.172(CAG)5-32 repeat polymorphisms of the ER-beta and AR was found in individuals of Greek descent.

Genetic background of the multifactorial liver and bile duct diseases

The majority of liver diseases, are complex. They are the results of interactions between several genes and environmental factors. Familial aggregation and higher concordance rate of monozygotic twins compared to those of dizygotic twins provide evidence for the importance of genetic factors in the pathogenesis. There are only limited data in connection with the genetic background of multifactorial liver diseases. In the future, the genetic background may permit prevention, early, accurate diagnosis, prediction of disease course, complications, prognosis, as well as treatment response.

Mechanisms for cellular cholesterol transport: defects and human disease

This review summarizes the mechanisms of cellular cholesterol transport and monogenic human diseases caused by defects in intracellular cholesterol processing. In addition, selected mouse models of disturbed cholesterol trafficking are discussed. Current pharmacological strategies to prevent atherosclerosis are largely based on altering cellular cholesterol balance and are introduced in this context. Finally, because of the organizing potential of cholesterol in membranes, disturbances in cellular cholesterol transport have implications for a wide variety of human diseases, of which selected examples are given.

Gallbladder cancer worldwide: geographical distribution and risk factors

Gallbladder cancer is a relatively rare neoplasm that shows, however, high incidence rates in certain world populations. The interplay of genetic susceptibility, lifestyle factors and infections in gallbladder carcinogenesis is still poorly understood. Age-adjusted rates were calculated by cancer registry-based data. Epidemiological studies on gallbladder cancer were selected through searches of literature, and relative risks were abstracted for major risk factors. The highest gallbladder cancer incidence rates worldwide were reported for women in Delhi, India (21.5/100,000), South Karachi, Pakistan (13.8/100,000) and Quito, Ecuador (12.9/100,000). High incidence was found in Korea and Japan and some central and eastern European countries. Female-to-male incidence ratios were generally around 3, but ranged from 1 in Far East Asia to over 5 in Spain and Colombia. History of gallstones was the strongest risk factor for gallbladder cancer, with a pooled relative risk (RR) of 4.9 [95% confidence interval (CI): 3.3-7.4]. Consistent associations were also present with obesity, multiparity and chronic infections like Salmonella typhi and S. paratyphi [pooled RR 4.8 (95% CI: 1.4-17.3)] and Helicobacter bilis and H. pylori [pooled RR 4.3 (95% CI: 2.1-8.8)]. Differences in incidence ratios point to variations in gallbladder cancer aetiology in different populations. Diagnosis of gallstones and removal of gallbladder currently represent the keystone to gallbladder cancer prevention, but interventions able to prevent obesity, cholecystitis and gallstone formation should be assessed.

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.

Hepatic cholesterol transport from plasma into bile: implications for gallstone disease

PURPOSE OF REVIEW

The transhepatic traffic of cholesterol from plasma lipoproteins into the bile is critical for overall cholesterol homeostasis and its alterations may lead to cholesterol gallstone formation. This review summarizes recent progress in understanding the key hepatic cholesterol metabolism-related proteins and pathways that influence biliary secretion of cholesterol.

RECENT FINDINGS

In cholesterol-fed apolipoprotein E knockout mice, the availability of dietary cholesterol for biliary disposal is decreased and diet-induced gallstone formation is impaired. Scavenger receptor class B type I is relevant for cholesterol transport from plasma HDL into the bile in chow-fed mice, however its expression is not critical for biliary cholesterol secretion and gallstone formation in lithogenic diet-fed mice. Intrahepatic cholesterol transport proteins (e.g. sterol carrier protein-2, Niemann Pick type C-1 protein) also determine liver cholesterol available for biliary secretion in mice. Genetic manipulation of canalicular ATP-binding cassette transporter G5 and G8 expression in mice has established their essential role for biliary cholesterol secretion.

SUMMARY

Recent studies have underscored that different proteins involved in hepatic cholesterol transport regulate the availability of cholesterol for biliary secretion. These advances may provide new avenues for prevention and treatment of various disease conditions linked to abnormal cholesterol metabolism.