Marcin Krawczyk

Publications of Marcin Krawczyk

• Common genetic variation in vitamin D metabolism is associated with liver stiffness.

  Authors: Frank Grünhage, Katrin Hochrath, Marcin Krawczyk, Aksana Höblinger, Barbara Obermayer-Pietsch, Jürgen Geisel, Michael Trauner, Tilman Sauerbruch, Frank Lammert

  Hepatology (Baltimore, Md.). 05/2012;

  BACKGROUND: Recently, genome-wide studies identified genetic variants that affect serum 25-hydroxyvitamin D levels in healthy populations (rs12785878, near dehydrocholesterol reductase, DHCR7;BACKGROUND: Recently, genome-wide studies identified genetic variants that affect serum 25-hydroxyvitamin D levels in healthy populations (rs12785878, near dehydrocholesterol reductase, DHCR7; rs10741657, near CYP2R1; and rs7041, near vitamin D binding protein, GC). Since vitamin D deficiency is associated with advanced liver disease, we hypothesized that these variants are associated with 25(OH)-vitamin D levels and liver fibrosis. PATIENTS AND METHODS: Overall, 712 Caucasian patients with chronic liver diseases were included. Liver fibrosis was assessed by transient elastography (TE) and/or histology. Serum levels of 25(OH)-vitamin D were correlated with TE and fibrosis stages. Genotypes were determined using TaqMan assays and tested for association with vitamin D and liver stiffness. RESULTS: Serum 25(OH)-vitamin D levels were inversely correlated with liver stiffness and histology (p < 0.001). Homozygous carriers of the rare DHCR7 allele or the common CYP2R1 allele presented with reduced 25(OH)-vitamin D levels (p < 0.05). The variant rs12785878 in the DHCR7 locus was associated with liver stiffness in both patients with TE < 7.0 kPa and TE between 7.0 and 9.5 kPa. 25(OH)-vitamin D levels correlated with sunshine hours at time of inclusion (p < 0.001). CONCLUSIONS: Common variation in 25(OH)-vitamin D metabolism is associated with liver stiffness in patients presenting with low to moderately increased elasticity. Although the susceptible DHCR7 genotype confers small risk, we speculate that the observed stiffness differences indicate a stronger influence of 25(OH)-vitamin D on initiation rather than progression of hepatic fibrosis. (HEPATOLOGY 2012.).

• Phytosterol and cholesterol precursor levels indicate increased cholesterol excretion and biosynthesis in gallstone patients.

  Authors: Marcin Krawczyk, Dieter Lütjohann, Ramin Schirin-Sokhan, Luis Villarroel, Flavio Nervi, Fernando Pimentel, Frank Lammert, Juan Francisco Miquel

  Hepatology (Baltimore, Md.). 12/2011;

  In hepatocytes and enterocytes sterol uptake and secretion is mediated by NPC1L1 and ABCG5/8 proteins, respectively. Whereas serum levels of phytosterols represent surrogate markers for intestinalIn hepatocytes and enterocytes sterol uptake and secretion is mediated by NPC1L1 and ABCG5/8 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 GC-MS. Gallbladder bile sterol levels were analyzed in cholesterol GSD and controls (n=17 each). 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 to controls. In the follow-up study, serum phytosterol levels were significantly lower even before GSD were 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. Conclusions: 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 2011.).

• Pancreatic cancer risk variant ABO rs505922 in patients with cholangiocarcinoma.

  Authors: Marcin Krawczyk, Florentina Mihalache, Aksana Höblinger, Monica Acalovschi, Frank Lammert, Vincent Zimmer

  World journal of gastroenterology : WJG. 11/2011; 17(41):4640-2.

  The aim of this study was to investigate an association between the development of cholangiocarcinoma (CCA) and the ABO variant rs505922 (known to increase pancreatic cancer risk) in a large cohortThe aim of this study was to investigate an association between the development of cholangiocarcinoma (CCA) and the ABO variant rs505922 (known to increase pancreatic cancer risk) in a large cohort of European individuals with CCA. In total, 180 individuals with CCA and 350 CCA-free controls were included. The ABO variant rs505922 was genotyped using a polymerase chain reaction-based assay. Association between this single nucleotide polymorphism (SNP) and CCA was tested in contingency tables. Neither allele distributions nor association tests and regression analysis provided evidence for an increased risk of CCA among carriers of the ABO variant (all P > 0.05). Nevertheless, we documented a deviation from Hardy-Weinberg equilibrium in the entire CCA cohort (P = 0.028) and for patients with intrahepatic (P = 0.037) but not extrahepatic tumor localization (P > 0.05). The association tests did not provide evidence for a prominent role of the investigated SNP in the genetic risk of CCA. However, Hardy-Weinberg disequilibrium in the entire cohort and the intrahepatic CCA subgroup warrants future studies investigating a potential CCA risk modulation by individual blood groups.

• Dissecting the genetic heterogeneity of gallbladder stone formation.

  Authors: Marcin Krawczyk, David Q-H Wang, Piero Portincasa, Frank Lammert

  Seminars in liver disease. 05/2011; 31(2):157-72.

  Gallstone disease affects almost 20% of individuals in Westernized countries. As its incidence in the developing countries is rising considerably, currently, it is the second most commonGallstone disease affects almost 20% of individuals in Westernized countries. As its incidence in the developing countries is rising considerably, currently, it is the second most common gastroenterological condition worldwide. Gallstone formation is driven by an interaction between genetic and environmental risk factors. Previous studies have demonstrated that the genetic background accounts for ~25% of the total disease risk. Linkage and case-control studies of candidate genes and recent genome-wide studies have identified multiple lithogenic genes, in particular the hepatocanalicular cholesterol transporter ABCG5/G8 and the bilirubin conjugating enzyme UGT1A1, as major genetic determinants of gallstones in humans. In this review, we summarize the recent findings related to the genetics of cholelithiasis, update the "inventory" of human lithogenic genes, and relate the genetic studies to the pathobiologic background of the disease. In closing, future applications of genetic testing for gallstone carriers and asymptomatic family members are addressed.

• Gallstones: environment, lifestyle and genes.

  Authors: Caroline S Stokes, Marcin Krawczyk, Frank Lammert

  Digestive diseases (Basel, Switzerland). 01/2011; 29(2):191-201.

  Gallstone disease represents one of the most common and costly gastroenterological disorders. In Germany, 0.25% of the population undergo cholecystectomy per year, and cholelithiasis incurs annualGallstone disease represents one of the most common and costly gastroenterological disorders. In Germany, 0.25% of the population undergo cholecystectomy per year, and cholelithiasis incurs annual medical expenses of more than USD 6.5 billion in the United States. The paradigm of environmental risk factors for gallstones has lately been challenged by genetic studies in experimental models and humans. The analysis of more than 40,000 Swedish twin pairs with gallstones demonstrated that genetic factors account for 25% of the phenotypic variance. Since then, studies employing genome-wide association analysis, case-control cohorts and analysis of sib-pairs in families with gallstones have expanded our knowledge of 'gallstone genes'. Indeed, gallstone disease phenotypes are likely to result from the complex interaction of genetic factors, chronic overnutrition with carbohydrates, depletion of dietary fibre and other not fully defined environmental factors including physical inactivity and infections. This hypothesis is supported by the profound increases of cholesterol gallstone prevalence rates in Native Americans, post-war European countries and current urban centres in East Asia, all of which were associated with 'westernized' nutrition. Herein, we summarise the spectrum of environmental and genetic risk factors which should pave the way to 'personalised' strategies for the prevention and therapy of gallstones.

• Variant adiponutrin (PNPLA3) represents a common fibrosis risk gene: non-invasive elastography-based study in chronic liver disease.

  Authors: Marcin Krawczyk, Frank Grünhage, Vincent Zimmer, Frank Lammert

  Journal of hepatology. 12/2010; 55(2):299-306.

  Recent genome-wide association studies have identified the variant p.I148M of the adiponutrin gene PNPLA3 as a risk factor for developing severe forms of non-alcoholic and alcoholic liver diseases.Recent genome-wide association studies have identified the variant p.I148M of the adiponutrin gene PNPLA3 as a risk factor for developing severe forms of non-alcoholic and alcoholic liver diseases. The risk allele confers an increased risk for fatty liver disease and elevated serum aminotransferase activities reflecting liver injury. In the current elastography-based study, we investigate variant adiponutrin as genetic determinant of liver fibrosis, the hallmark of all chronic liver diseases. In this observational cross-sectional study, we staged 899 patients with different chronic liver diseases non-invasively by transient elastography (Fibroscan) and genotyped them for variant adiponutrin (rs738409) by PCR-based assays. A subgroup of 229 patients consented to percutaneous liver biopsy, validating the accuracy of elastography in staging fibrosis (ρ=0.743, p<0.01). Carriers of distinct p.I148M adiponutrin genotypes display significant (p=0.017) differences in liver stiffness determined by elastography. In particular, individuals carrying the allele [G] are at higher risk of developing liver cirrhosis defined by stiffness values ≥13.0kPa (OR=1.56, p=0.005). Of note, the PNPLA3 risk variant advances fibrosis in the total cohort as well as in the subgroups of patients with viral hepatitis and non-viral liver diseases and contributes 16% of the total cirrhosis risk. The adiponutrin risk variant is a common genetic determinant of progressive liver fibrosis. Our results underpin non-invasive follow-up for individuals with chronic liver disease at-risk for developing advanced fibrosis and cirrhosis.

• Genome-wide association studies and genetic risk assessment of liver diseases.

  Authors: Marcin Krawczyk, Roman Müllenbach, Susanne N Weber, Vincent Zimmer, Frank Lammert

  Nature reviews. Gastroenterology & hepatology. 11/2010; 7(12):669-81.

  Genetic tests can help clinicians to diagnose rare monogenic liver diseases. For most common liver diseases, however, multiple gene variants that have small to moderate individual phenotypic effectsGenetic tests can help clinicians to diagnose rare monogenic liver diseases. For most common liver diseases, however, multiple gene variants that have small to moderate individual phenotypic effects contribute to the overall risk of disease. An individual's level of risk depends on interactions between environmental factors and a wide range of modifier genes, which are yet to be identified systematically. The latest genome-wide association studies in large cohorts of patients with gallstones, fatty liver disease, viral hepatitis, chronic cholestatic liver diseases or drug-induced liver injury have provided new insights into the pathophysiology of these illnesses and have suggested the contribution of previously unsuspected pathogenic pathways. Studies in mouse models have identified further susceptibility genes for several complex liver diseases. As a result, in the future polygenic risk scores might help to define subgroups of patients at risk of developing liver diseases who would benefit from preventative measures and/or personalized therapy. Now that whole-genome sequencing is possible, comprehensive strategies for integrating genomic data and counseling of patients need to be developed.

• Nonalcoholic fatty liver disease.

  Authors: Marcin Krawczyk, Leonilde Bonfrate, Piero Portincasa

  Best practice & research. Clinical gastroenterology. 10/2010; 24(5):695-708.

  Non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in the Western world, is a clinico-histopathological entity in which excessive triglyceride accumulation in the liver occurs.Non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in the Western world, is a clinico-histopathological entity in which excessive triglyceride accumulation in the liver occurs. Non-alcoholic steatohepatitis (NASH) represents the necroinflammatory form, which can lead to advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. The pathogenesis of NAFLD/NASH is complex but increased visceral adiposity plus insulin resistance with increased free fatty acids release play an initial key role for the onset and perpetuation of liver steatosis. Further events in the liver include oxidative stress and lipid peroxidation, decreased antioxidant defences, early mitochondrial dysfunction, iron accumulation, unbalance of adipose-derived adipokines with a chronic proinflammatory status, and gut-derived microbial adducts. New gene polymorphisms increasing the risk of fatty liver, namely APOC3 and PNPLA3, have been lately identified allowing further insights into the pathogenesis of this condition. In our review pathophysiological, genetic, and essential diagnostic and therapeutic aspects of NAFLD are examined with future trends in this field highlighted.

• Analysis of the common vasoactive intestinal peptide receptor 1 polymorphism in gallstone patients.

  Authors: Marcin Krawczyk, Monica Rusticeanu, Frank Grünhage, Miriam Mahler, Piero Portincasa, Monica Acalovschi, Frank Lammert

  Journal of gastrointestinal and liver diseases : JGLD. 09/2010; 19(3):273-7.

  Cholesterol gallstone disease is caused by both genetic and environmental factors (e.g., deranged motility of the gallbladder wall). Recently, a single nucleotide polymorphism (SNP) of the vasoactiveCholesterol gallstone disease is caused by both genetic and environmental factors (e.g., deranged motility of the gallbladder wall). Recently, a single nucleotide polymorphism (SNP) of the vasoactive intestinal peptide receptor 1 (VIPR1) gene has been linked to late onset of achalasia, a lower esophagus dysmotility disorder. As VIPR1 is expressed in the gallbladder wall as well, and patients with achalasia exhibit extraesophageal motility disorders, the influence of VIPR1 SNP on cholelithiasis was investigated. We analyzed 254 gallstone-free controls (confirmed by ultrasound, age 21-78 years, 88% women, BMI 16-43 kg/m²) and 226 individuals from 107 families with gallstones (age 24-80 years, 87% women, BMI 17-55 kg/m²). All individuals were genotyped for the VIPR1 rs437876 SNP (intron 4) with PCR-based 5'-nuclease and fluorescence detection assays (TaqMan). We performed nonparametric linkage (NPL) analysis in affected sib-pairs (ASP), association tests, and regression analyses. Controls were significantly younger (P < 0.01) and leaner than ASP and cases (P < 0.01), and both age as well as BMI significantly increased the risk of developing gallstones (P < 0.001). Allele frequencies were in line with database entries and no deviation from Hardy-Weinberg equilibrium was detected. Neither allele and genotype distributions nor NPL scores or the restriction of analysis to individuals older than 50 years provided evidence for association or linkage of the VIPR1 SNP and cholelithiasis. The VIPR1 polymorphism, previously linked to gastrointestinal dysmotility disorders, does not represent a common risk factor for gallstones in the general or in an elderly population.

• Common Variants of ABCB4 and ABCB11 and Plasma Lipid Levels: A Study in Sib Pairs with Gallstones, and Controls.

  Authors: Monica Acalovschi, Simona Tirziu, Erica Chiorean, Marcin Krawczyk, Frank Grünhage, Frank Lammert

  Lipids. 04/2009;

  Most epidemiological surveys have confirmed the association of low HDL-cholesterol and high triglyceride levels with cholesterol gallstones. Our objective was to analyze the relationship betweenMost epidemiological surveys have confirmed the association of low HDL-cholesterol and high triglyceride levels with cholesterol gallstones. Our objective was to analyze the relationship between plasma lipid levels and common polymorphisms of ABCB11 (encoding the bile salt export pump, BSEP) and ABCB4 (encoding the phospholipid transporter into bile, MDR3) genes. Plasma lipids were measured in 108 index patients of sib pairs with gallstones and in 260 controls. Using PCR-based assays with 5'-nuclease and fluorescence detection (TaqMan), the ABCB11 coding SNP p.A444V and four haplotype-tagging SNPs covering the ABCB4 gene (c.504C > T, c.711T > A, p.R652G, rs31653 in intron 26) were genotyped. Plasma lipids were compared in carriers of the common versus rare allele of these polymorphisms using Student's t test and Pearson's correlation. BMI and triglyceride levels were higher and HDL-cholesterol levels were lower in affected siblings than in controls. Among cases, triglyceride and cholesterol levels were higher in carriers of the common versus rare (hetero/homozygous carriers) allele of the SNPs p.A444V of ABCB11 and C.504C > T of ABCB4. HDL-cholesterol was lower in carriers of the common allele of rs31653. In controls, significant differences of cholesterol and HDL-cholesterol levels were found in carriers of ABCB4 polymorphisms. Our results do not support the hypothesis of a link between ABCB4 and ABCB11 polymorphisms, lithogenic dyslipidemia, and gallstone risk.

• A Variant of the SLC10A2 Gene Encoding the Apical Sodium-Dependent Bile Acid Transporter Is a Risk Factor for Gallstone Disease.

  Authors: Olga Renner, Simone Harsch, Elke Schaeffeler, Stefan Winter, Matthias Schwab, Marcin Krawczyk, Jonas Rosendahl, Henning Wittenburg, Frank Lammert, Eduard F Stange

  PloS one. 01/2009; 4(10):e7321.

  BACKGROUND: Cholelithiasis is a multifactorial process and several mechanisms of gallstone formation have been postulated. As one of these mechanisms, a decreased expression of the ileal apicalBACKGROUND: Cholelithiasis is a multifactorial process and several mechanisms of gallstone formation have been postulated. As one of these mechanisms, a decreased expression of the ileal apical sodium-dependent bile acid transporter gene SLC10A2 in gallstone carriers was described previously. In this study the SLC10A2 gene was investigated to identify novel genetic variants and their association with gallstone formation. METHODOLOGY/PRINCIPAL FINDINGS: Study subjects were selected with the presence or absence of gallstones confirmed by ultrasound and medical history. Genomic DNA was obtained from blood leukocytes. Sequence analysis was performed of all six exonic and flanking regions as well as of 2,400 base pairs of the SLC10A2 promoter in a cohort of gallstone carriers and control subjects from Stuttgart, Germany. Genotype frequencies of newly identified genetic variants (n = 6) and known single nucleotide polymorphisms (n = 24) were established using MALDI-TOF mass spectrometry. Six new genetic variants were found within the SLC10A2 gene. Although none of the variants was linked to gallstone disease in the Stuttgart cohort overall, the minor allele of SNP rs9514089 was more prevalent in male non-obese gallstone carriers (p = 0.06680, OR = 11.00). In a separate population from Aachen, Germany, the occurrence of rs9514089 was two-fold higher in gallstone patients (22%) than in corresponding controls (11%) (p = 0.00995, OR = 2.19). In the pooled Aachen/Stuttgart cohort rs9514089 was highly significantly linked to cholelithiasis (p = 0.00767, OR = 2.04). A more frequent occurrence was observed for male gallstone carriers (22%) compared to controls (9%) (p = 0.01017, OR = 2.99), for the total normal weight group (p = 0.00754, OR = 2.90), and for male non-obese gallstone patients (p = 0.01410, OR = 6.85). Moreover, for the minor allele of rs9514089 an association with low plasma cholesterol levels was found especially in gallstone carriers (p = 0.05). CONCLUSIONS/SIGNIFICANCE: We have identified SLC10A2 as a novel susceptibility gene for cholelithiasis in humans. Comprehensive statistical analysis provides strong evidence that rs9514089 is a genetic determinant especially in male non-obese gallstone carriers. The minor allele of rs9514089 is related to differences in plasma cholesterol levels among the subjects.

• Concordance of genetic and breath tests for lactose intolerance in a tertiary referral centre.

  Authors: Marcin Krawczyk, Malgorzata Wolska, Stephanie Schwartz, Frank Gruenhage, Birgit Terjung, Piero Portincasa, Tilman Sauerbruch, Frank Lammert

  Journal of gastrointestinal and liver diseases : JGLD. 06/2008; 17(2):135-9.

  BACKGROUND AND AIMS. Lactase non-persistence causes gastrointestinal symptoms after milk ingestion. Hydrogen breath test (BTH) and genotyping of a single nucleotide polymorphism (SNP) C>T 13,910 baseBACKGROUND AND AIMS. Lactase non-persistence causes gastrointestinal symptoms after milk ingestion. Hydrogen breath test (BTH) and genotyping of a single nucleotide polymorphism (SNP) C>T 13,910 base pairs upstream of the lactase gene represent potential methods for diagnosis of this autosomal-recessive trait. The aim of the study was to compare the results of both tests in detecting lactose non-persistence in a tertiary referral centre. PATIENTS. A group of 58 patients admitted to a German university hospital for symptoms suggesting lactose intolerance. METHODS. BTH after lactose ingestion (50 g) and SNP -13,910C>T genotyping using single nucleotide primer extension (SNaPshot) technology (CC genotype - lactase non-persistence; TC/TT genotypes - lactase persistence). RESULTS. Overall, 17 (29%) patients had a positive and 41 (71%) had a negative BTH result; 15 (26%) patients were CC-positive and 43 (74%) were CC-negative [28 (48%) TC; 15 (26%) TT]. The genotype frequencies did not deviate from the Hardy-Weinberg equilibrium. In the CC-positive group, concordance between both tests was 100%. In contrast, in the CC-negative group concordance was 95%, and positive BTH results could be attributed to other gastrointestinal pathologies in two patients. BTH had 100% negative predictive value, 88% positive predictive value, 100% sensitivity and 95% specificity, as compared to genetic testing. CONCLUSIONS. In carriers of the CC-genotype, BTH and genotyping correlate perfectly, and the genetic test provides an unambiguous result. In BTH-positive individuals with a negative genetic test there is good reason to suspect secondary causes of lactase deficiency.

• The "hemolysis model" for the study of cyto-toxicity and cyto-protection by bile salts and phospholipids.

  Authors: Piero Portincasa, Antonio Moschetta, Michele Petruzzelli, Michele Vacca, Marcin Krawczyk, Francesco Minerva, Vincenzo O Palmieri, Giuseppe Palasciano

  Advances in experimental medicine and biology. 02/2006; 578:93-9.