Browsing by Author "Lammert, Frank"
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- ItemEzetimibe prevents cholesterol gallstone formation in mice(2008) Zuñiga, Silvia Eugenia; Molina, Héctor; Azócar, Lorena; Amigo Boker, Ludwig Peter; Nervi Oddone, Flavio; Pimentel Muller, Fernando Ernesto; Jarufe Cassis, Nicolas Patricio; Arrese Jimenez, Marco Antonio; Lammert, Frank; Miquel Poblete, Juan FranciscoBackground: Intestinal cholesterol absorption may influence gallstone formation and its modulation could be a useful therapeutic strategy for gallstone disease (GSD). Ezetimibe (EZET) is a cholesterol-lowering agent that specifically inhibits intestinal cholesterol absorption. Aims: To test whether EZET can prevent gallstone formation in mice. Methods/Results: Gallstone-susceptible C57BL/6 inbred mice were fed control and lithogenic diets with or without simultaneous EZET administration. Lithogenic diet increased biliary cholesterol content and secretion, and induced sludge or gallstone formation in 100% of the animals. EZET administration reduced intestinal cholesterol absorption by 90% in control animals and by 35% in mice receiving the lithogenic diet. EZET prevented the appearance of cholesterol crystals and gallstones. In addition, mice fed the lithogenic diet plus EZET exhibited a 60% reduction in biliary cholesterol saturation index. Of note, EZET treatment caused a significant increase in bile flow (+50%, P < 0.01) as well as bile salt, phospholipid and glutathione secretion rates (+60%, +44% and +100%, respectively, P < 0.01), which was associated with a moderately increased expression of hepatic bile salt transporters. In addition, relative expression levels of Nieman-Pick C1 like 1 (NPC1L1) in the enterohepatic axis in humans were assessed. Expression levels of NPC1L1 were 15-to 30-fold higher in the duodenum compared with the liver at transcript and protein levels, respectively, suggesting preferential action of EZET on intestinal cholesterol absorption in humans. Conclusions: In a murine model of GSD, EZET prevented gallstone formation by reducing intestinal cholesterol absorption and increasing bile salt-dependent and -independent bile flow. EZET could be useful in preventing GSD disease in susceptible patients.
- ItemGallstone disease: From genes to evidence-based therapy(2008) Lammert, Frank; Miquel Poblete, Juan FranciscoThe number of gallstone patients is increasing in ageing populations with a high prevalence of metabolic syndrome and obesity. Recently variants of hepatic ATP binding cassette transporters have been identified as genetic susceptibility factors for gallstone disease, pointing to novel means for risk assessment and prevention. Although laparoscopic cholecystectomy is the mainstay of therapy for symptomatic gallbladder stones, the clinical management of gallstone disease is changing rapidly, with an increase in day case surgery and the advent of transluminal endoscopic surgery. Here, we summarize the molecular and genetic mechanisms of gallstone formation as well as the current evidence-based algorithms for diagnosis and therapy of gallbladder and bile duct stones. (c) 2008 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.
- ItemGallstones(2016) Lammert, Frank; Gurusamy, Kurinchi; Ko, Cynthia W.; Miquel P., Juan Francisco; Méndez Sánchez, Nahum; Portincasa, Piero; Van Erpecum, Karel J.; Van Laarhoven, Cees J.; Wang, David Q.-H.
- ItemGenetic evidence that apolipoprotein E4 is not a relevant susceptibility factor for cholelithiasis in two high-risk populations(AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 2007) Mella, Juan G.; Schirin Sokhan, Ramin; Rigotti, Attilio; Pimentel, Fernando; Villarroel, Luis; Wasmuth, Hermann E.; Sauerbruch, Tilman; Nervi, Flavio; Lammert, Frank; Miquel, Juan FranciscoApolipoprotein E (apoE) isoforms are genetic determinants of interindividual variations in lipid metabolism. To assess whether apoE is a genetic risk factor for cholesterol gallstone disease (GD), we analyzed apoE variants in populations from Chile and Germany, two countries with very high prevalence rates of this disease. ApoE genotypes were determined in Chilean gallstone patients (n = 117) and control subjects (n = 122) as well as in German gallstone patients ( n 5 184) and matched controls (n = 184). In addition, we studied apoE variants in subgroups of Chilean patients with strong differences in their susceptibility to acquire gallstones: 50 elderly subjects without gallstones in spite of well-known risk factors for this disease (gallstone-resistant) and 32 young individuals with gallstones but without risk factors (gallstone-susceptible). Furthermore, correlation analysis of apoE genotypes with cholesterol crystal formation times, biliary cholesterol saturation index (CSI), and gallstone cholesterol contents was performed in 81 cholecystectomized patients. In this study analyzing the largest sample set available, apoE4 genotype was not associated with an increased frequency of GD in either population. Moreover, in the Chilean population after adjusting for risk factors such as gender, age, body mass index, serum lipids, and glucose, the odds ratio for the association of the apoE4 allele and GD was significantly (P < 0.05) < 1. Also, genotypes were not correlated with cholesterol crystal formation time, CSI, or gallstone cholesterol content. In contrast to previous smaller studies, apoE polymorphisms were not associated with susceptibility to cholesterol GD in high-risk populations.
- ItemGenetics of biliary lithiasis from an ethnic perspective(2013) Krawczyk, Marcin; Miquel Poblete, Juan Francisco; Stokes, Caroline S.; Zuniga, Silvia; Hampe, Jochen; Mittal, Balraj; Lammert, FrankGallstone disease represents one of the most common gastroenterological disorders worldwide. Gallstones affect over 15% of adults in Europe and 25-30% of Hispanic populations in Central and South America. The heritability of gallstones varies considerably according to ethnicity, with Native Americans and Hispanics with Amerindian admixture being the most susceptible populations. Genetic factors have been shown to account for 25-30% of total gallstone risk in Europe, however, in Hispanic populations, this risk percentage may increase to 45-65%. Recent genome-wide association and candidate gene studies have identified common polymorphisms in enterohepatic transporters (ABCG5/8, SLC10A2) and the Gilbert syndrome UGT1A1 variant as genetic determinants of gallstone formation. Together, these polymorphisms cover a significant proportion of the previously predicted genetic background of gallstones in European populations. New lithogenic genes need to be discovered in future studies in high-risk populations. In this review, we address the latest developments in the genetic analysis of gallstones and discuss the ethnic background of this condition in European, Central and South American and Asian populations. (C) 2012 Elsevier Masson SAS. All rights reserved.
- ItemPhytosterol and cholesterol precursor levels indicate increased cholesterol excretion and biosynthesis in gallstone disease(WILEY-BLACKWELL, 2012) Krawczyk, Marcin; Luetjohann, Dieter; Schirin Sokhan, Ramin; Villarroel, Luis; Nervi, Flavio; Pimentel, Fernando; Lammert, Frank; Francisco Miquel, JuanIn hepatocytes and enterocytes sterol uptake and secretion is mediated by Niemann-Pick C1-like 1 (NPC1L1) and ATP-binding cassette (ABC)G5/8 proteins, respectively. Whereas serum levels of phytosterols represent surrogate markers for intestinal cholesterol absorption, cholesterol precursors reflect cholesterol biosynthesis. Here we compare serum and biliary sterol levels in ethnically different populations of patients with gallstone disease (GSD) and stone-free controls to identify differences in cholesterol transport and synthesis between these groups. In this case-control study four cohorts were analyzed: 112 German patients with GSD and 152 controls; two distinct Chilean ethnic groups: Hispanics (100 GSD, 100 controls), and Amerindians (20 GSD, 20 controls); additionally an 8-year follow-up of 70 Hispanics was performed. Serum sterols were measured by gas chromatography / mass spectrometry. Gallbladder bile sterol levels were analyzed in cholesterol GSD and controls. Common ABCG5/8 variants were genotyped. Comparison of serum sterols showed lower levels of phytosterols and higher levels of cholesterol precursors in GSD patients than in controls. The ratios of phytosterols to cholesterol precursors were lower in GSD patients, whereas biliary phytosterol and cholesterol concentrations were elevated as compared with controls. In the follow-up study, serum phytosterol levels were significantly lower even before GSD was detectable by ultrasound. An ethnic gradient in the ratios of phytosterols to cholesterol precursors was apparent (Germans > Hispanics > Amerindians). ABCG5/8 variants did not fully explain the sterol metabolic trait of GSD in any of the cohorts. Conclusion: Individuals predisposed to GSD display increased biliary output of cholesterol in the setting of relatively low intestinal cholesterol absorption, indicating enhanced whole-body sterol clearance. This metabolic trait precedes gallstone formation and is a feature of ethnic groups at higher risk of cholesterol GSD. (HEPATOLOGY 2012)
- ItemVariation of the gene encoding the nuclear bile salt receptor FXR and gallstone susceptibility in mice and humans(ELSEVIER SCIENCE BV, 2008) Kovacs, Peter; Kress, Rahel; Rocha, Jacqueline; Kurtz, Ulrike; Miquel, Juan Francisco; Nervi, Flavio; Mendez Sanchez, Nahum; Uribe, Misael; Bock, Hans H.; Schirin Sokhan, Ramin; Stumvoll, Michael; Moessner, Joachim; Lammert, Frank; Wittenburg, HenningBackground/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.