The main research effort of the lab concerns chronic pancreatitis and the
inherited form of diabetes called MODY8. The basis for this project is the discovery (Ræder et al., Nature Genetics 2006) that mutations in the CEL gene can cause MODY8, characterized by both diabetes and exocrine pancreatic dysfunction. The CEL gene encodes the digestive enzyme carboxyl-ester lipase, also known as bile salt-dependent lipase. We aim to understand the molecular processes that cause MODY8 and are also investigating whether variants in CEL associate with chronic pancreatitis and pancreatic cancer. Click here for a description of some results with regard to the disease mechanism. We have also recently been involved in a study from Joslin Diabetes Center, Boston that further elucidated the pathogenesis of MODY8.


Expression of CEL mRNA (red) and protein (green) in an
acinus (encircled), the functional cell unit producing the
digestive enzymes of the exocrine pancreas (El Jellas 2018).

In 2015, we discovered a hybrid gene variant (CEL-HYB) that has originated from a recombination between CEL and its neighboring pseudogene CELP. This variant is a significant risk factor for chronic pancreatitis and our findings implicate a new pathway in this disease. The data were published in Nature Genetics (Fjeld et al. 2015), whereas a popular description can be found here. We are performing in-depth analyses of the properties of CEL-HYB, including a characterization of how different subtypes of this risk factor contribute to chronic pancreatitis. Moreover, o
ur ongoing studies now include the establishment of animal models for CEL-mediated chronic pancreatitis.


Current participants / main collaborators

Researcher Karianne Fjeld, Gade Laboratory for Pathology, UoBergen
PhD student Renate V. Seierstad, Gade Laboratory for Pathology, UoBergen
PhD student Ranveig Seim Brekke, Gade Laboratory for Pathology, UoBergen
Senior technician Anny Gravdal, Gade Laboratory for Pathology, UoBergen
Master student Silje H. Johansen, Dept. of Biomedicine, UoBergen
Master student Hanna Svendsen, Dept. of Biomedicine, UoBergen
Master student Diego I. López, Dept. of Biomedicine, UoBergen
Erasmus student Melanie Stammler, Technical Univeristy of Munich, Germany
Senior technician Solrun Steine, Gade Laboratory for Pathology, UoBergen
Postdoc Khadija El Jellas, Joslin Diabetes Center, Harvard Medical School, Boston, USA
Researcher Bente B. Johansson, Dept. of Clinical Science, UoBergen
Consultant Erling Tjora, Dept. of Pediatrics, Haukeland Univ. Hospital, Bergen
Consultant Trond Engjom, Dept. of Gastroenterology, Haukeland Univ. Hospital, Bergen
Professor Pål R. Njølstad, Dept. of Clinical Science, UoBergen
Professor Caroline S. Verbeke, Department of Pathology, University of Oslo, Norway
Professor Barbara Kahn, Beth Israel Deaconess Medical Center, Boston, USA
Professor Rohit N. Kulkarni, Joslin Diabetes Center, Harvard Medical School, Boston, USA
Ass. Professor Xunjun Xiao, Washington University, St. Louis, USA
Professor Mark E. Lowe, Washington University, St. Louis, USA
Professor Frank Ulrich Weiss, Greifswald University, Germany
Professor Jonas Rosendahl, Martin Luther University Halle-Wittenberg, Germany


Brekke RS, Gravdal A, El Jellas K, Curry GE, Lin J, Wilhelm SJ, Steine SJ, Mas E, Johansson S, Lowe ME, Johansson BB, Xiao X, Fjeld K & Molven A (2024). Common single-base insertions in the VNTR of the carboxyl ester lipase (CEL) gene are benign and also likely to arise somatically in the exocrine pancreas. Human Molecular Genetics 33: 1001-1014.

Fjeld K, Gravdal A, Brekke RS, Alam J, Wilhelm SJ, El Jellas K, Pettersen HN, Lin J, Solheim MH, Steine SJ, Johansson BB, Njølstad PR, Verbeke CS, Xiao X, Lowe ME & Molven A (2022). The genetic risk factor CEL-HYB1 causes proteotoxicity and chronic pancreatitis in mice. Pancreatology 22: 1099-1111.

Kahraman S, Dirice E, Basile G, Diegisser D, Alam J, Johansson BB, Gupta MK, Hu J, Huang L, Soh C-L, Huangfu D, Muthuswamy SK, Ræder H, Molven A & Kulkarni RN (2022). Abnormal exocrine-endocrine cell cross-talk promotes β-cell dysfunction and loss in MODY8. Nature Metabolism 4: 76-89.

El Jellas K, Dušátková P, Haldorsen IS, Molnes J, Tjora E, Johansson BB, Fjeld K, Johansson S, Průhová Š, Groop L, Löhr J-M, Pål R. Njølstad PR & Molven A (2022). Two new mutations in the CEL gene causing diabetes and hereditary pancreatitis: How to correctly identify MODY8 cases. Journal of Clinical Endocrinology & Metabolism 107: e1455-1466.

Gravdal A, Xiao X, Cnop M, El Jellas K, Johansson S, Njølstad PR, Lowe ME, Johansson BB, Molven A & Fjeld K (2021). The position of single-base deletions in the VNTR sequence of the carboxyl ester lipase (CEL) gene determines proteotoxicity. Journal of Biological Chemistry 296: 100661.

Choi MH, Tjora E, Forthun RB, Engjom T, Ræder H, Hovland R & Molven A (2021). KRAS mutation analysis by droplet digital PCR of duodenal juice from patients with MODY8 and other pancreatic diseases. Pancreatology 21: 1460-1465.

Tjora E, Gravdal A, Engjom T, Johansson BB, Dimcevski GG, Molven A & Fjeld K (2021). First clinical reports on CEL-HYB-positive carriers: An interplay between protein misfolding and other risk factors in pancreatitis. European Journal of Gastroenterology & Hepatology 33: 839-843.

Fjeld K, Masson E, Lin JH, Michl P, Stokowy T, Gravdal A, El Jellas K, Steine SJ, Hoem D, Johansson BB, Dalva M, Ruffert C, Zou WB, Li ZS, Njølstad PR, Chen JM, Liao Z, Johansson S, Rosendahl J, Férec C & Molven A (2020). Characterization of CEL-DUP2: Complete duplication of the carboxyl ester lipase gene is unlikely to influence risk of chronic pancreatitis. Pancreatology 20: 377-384.

Cassidy B, Zino S, Fjeld K, Molven A, Lowe ME & Xiao X (2020). Single nucleotide polymorphisms in CEL-HYB1 increase risk for chronic pancreatitis through proteotoxic protein misfolding. Human Mutation 41: 1967-1978.

Dalva M, Lavik IK, El Jellas K, Gravdal A, Lugea A, Pandol SJ, Njølstad PR, Waldron RT, Fjeld K, Johansson BB & Molven A (2020). Pathogenic carboxyl-ester lipase (CEL) variants interact with the normal CEL protein in pancreatic cells. Cells 9: E244.

Oracz G, Kujko AA, Fjeld K, Wertheim-Tysarowska K, Adamus-Białek W, Steine SJ, Koziel D, Gluszek S, Molven A & Rygiel AM (2019). The hybrid allele 1 of carboxyl-ester lipase (CEL-HYB1) in Polish pediatric patients with chronic pancreatitis. Pancreatology 19: 531-534.

Johansson BB, Fjeld K, El Jellas K, Gravdal A, Dalva M, Tjora E, Ræder H, Kulkarni RN, Johansson S, Njølstad PR & Molven  A (2018). The role of the carboxyl ester lipase (CEL) gene in pancreatic disease. Pancreatology 18:12-19.

El Jellas K, Johansson BB, Fjeld K, Antonopoulos A, Immervoll H, Choi MH, Hoem D, Lowe ME, Lombardo D, Njølstad PR, Dell A, Mas E, Haslam SM & Molven A (2018). The mucinous domain of pancreatic carboxyl-ester lipase (CEL) contains core 1/core 2 O-glycans that can be modified by ABO blood group determinants. Journal of Biological Chemistry 293:19476-19491.

Dalva M, El Jellas K, Steine SJ, Ringdal M, Torsvik J, Immervoll H, Lerch MM, Johansson BB, Hoem D, Johansson S, Njølstad PR, Weiss U, Fjeld K & Molven A (2017). Copy number variants and VNTR length polymorphisms of the carboxyl-ester lipase (CEL) gene as risk factors in pancreatic cancer. Pancreatology 17: 83-88.

Fjeld K, Beer S, Johnstone M, Zimmer C, Mössner J, Ruffert C, Krehan M, Zapf C, Njølstad PR, Johansson S, Bugert P, Miyajima F, Liloglou T, Brown LJ, Winn SA, Davies K, Latawiec D, Gunson BK, Criddle DN, Pirmohamed M, Grützmann R, Michl P, Greenhalf W, Molven A, Sutton R & Rosendahl J (2016). Length of variable numbers of tandem repeats in the carboxyl ester lipase (CEL) gene may confer susceptibility to alcoholic liver cirrhosis but not alcoholic chronic pancreatitis. PLoS One 11 (11): e0165567.

Kolar MJ, Kamat SS, Parsons WH, Homan EA, Maher T, Peroni OD, Syed I, Fjeld K, Molven A, Kahn BB, Cravatt BF & Saghatelian A (2016). Branched fatty acid esters of hydroxy fatty acids are preferred substrates of the MODY8 protein carboxyl ester lipase. Biochemistry 55: 4636-4641.

Molven A, Fjeld K & Lowe ME (2016). Lipase genetic variants in chronic pancreatitis: When the end is wrong, all’s not well. Gastroenterology 150: 1515-1518.

Fjeld K, Weiss FU, Lasher D, Rosendahl J, Chen JM, Johansson BB, Kirsten H, Ruffert C, Masson E, Steine SJ, Bugert P, Cnop M, Grützmann R, Mayerle J, Mössner J, Ringdal M, Schulz HU, Sendler M, Simon P, Sztromwasser P, Torsvik J, Scholz M, Tjora E, Férec C, Witt H, Lerch MM, Njølstad PR, Johansson S & Molven A (2015). A recombined allele of the lipase gene CEL and its pseudogene CELP confers susceptibility to chronic pancreatitis. Nature Genetics 47: 518-522.

Molven A, Njølstad PR & Weiss FU (2015). Lipase gene fusion: a new route to chronic pancreatitis. Oncotarget 6: 30443-30444.

Torsvik J, Johansson BB, Dalva M, Marie M, Fjeld K, Johansson S, Bjørkøy G, Saraste J, Njølstad PR & Molven A (2014). Endocytosis of secreted carboxyl-ester lipase in a syndrome of diabetes and pancreatic exocrine dysfunction. Journal of Biological Chemistry 289: 29097-29111.

Ræder H, McAllister FE, Tjora E, Bhatt S, Haldorsen I, Hu J, Willems SM, Vesterhus M, ElOuamaari A, Liu M, Raeder MB, Immervoll H, Hoem D, Dimcevski G, Njølstad PR, Molven A, Gygi SP & Kulkarni RN (2014). Carboxyl-ester lipase maturity-onset diabetes of the young is associated with development of pancreatic cysts and upregulated MAPK signaling in secretin-stimulated duodenal fluid. Diabetes 63: 259-269.

Wathle GK, Tjora E, Ersland L, Dimcevski G, Salvesen ØO, Molven A, Njølstad PR & Haldorsen  IS (2014). Assessment of exocrine pancreatic function by secretin stimulated MRCP and DWI in healthy controls. Journal of Magnetic Resonance Imaging 39: 448-454.

Ragvin A, Fjeld K, Weiss FU, Torsvik J, Aghdassi A, Mayerle J, Simon P, Njølstad PR, Lerch MM, Johansson S & Molven A (2013). The number of tandem repeats in the carboxyl-ester lipase (CEL) gene as a risk factor in alcoholic and idiopathic chronic pancreatitis. Pancreatology 13: 29-32.

Tjora E, Wathle G, Engjom T, Erchinger F, Molven A, Aksnes L, Haldorsen IS, Dimcevski GG, Njølstad PR & Ræder H (2013). Severe pancreatic dysfunction but compensated nutritional status in monogenic pancreatic disease caused by carboxyl-ester lipase mutations. Pancreas  42: 1078-1084.

Tjora E, Wathle G, Erchinger F, Engjom T, Molven A, Aksnes L, Haldorsen IS, Dimcevski G, Ræder H & Njølstad PR (2013). Exocrine pancreatic function in HNF1B-MODY is only moderately reduced: compensatory hypersecretion from a hypoplastic pancreas. Diabetic Medicine 30: 946-955.

Ræder H, Vesterhus M, El Ouaamari A, Paulo JA, McAllister FE, Liew CW, Hu J, Kawamori D, Molven A, Gygi SP, Njølstad PR, Kahn CR & Kulkarni RN (2013). Absence of diabetes and pancreatic exocrine dysfunction in a transgenic model of carboxyl-ester lipase-MODY (maturity-onset diabetes of the young). PloS ONE 8 (4): e60229.

Gonc EN, Ozturk BB, Haldorsen IS, Molnes J, Immervoll H, Ræder H, Molven A, Søvik O, & Njølstad PR (2012). HNF1B mutation in a Turkish child with renal and exocrine pancreas insufficiency, diabetes and liver disease. Pediatric Diabetes 13: e1-e5.

Johansson BB, Torsvik J, Bjørkhaug L, Vesterhus M, Ragvin A, Tjora E, Fjeld K, Hoem D, Johansson S, Ræder H, Lindquist S, Hernell O, Cnop M, Saraste J, Flatmark T, Molven A & Njølstad PR (2011). Diabetes and pancreatic exocrine dysfunction due to mutations in the carboxyl-ester lipase gene (CEL): a protein misfolding disease. Journal of Biological Chemistry 286: 34593-34605.

Vesterhus M, Ræder H, Kurpad AJ, Kawamori D, Molven A, Kulkarni RN, Kahn CR & Njølstad PR (2010). Pancreatic function in carboxyl-ester lipase knockout mice. Pancreatology 10: 467–476.

Torsvik J, Johansson S, Johansen A, Ek J, Minton J, Ræder H, Ellard S, Hattersley A, Pedersen O, Hansen T, Molven A & Njølstad PR (2010). Mutations in the VNTR of the carboxyl-ester lipase gene (CEL) are a rare cause of  monogenic diabetes. Human Genetics 127: 55-64.

Vesterhus M, Ræder H, Aurlien H, Gjesdal CG, Bredrup C, Holm PI, Molven A, Bindoff L, Berstad A & Njølstad PR (2008). Neurological features and enzyme therapy in patients with endocrine and exocrine pancreas dysfunction due to CEL mutations. Diabetes Care 31: 1738-1740.

Vesterhus M, Haldorsen IS, Ræder H, Molven A & Njølstad PR (2008). Reduced pancreatic volume in hepatocyte nuclear factor 1A-maturity-onset diabetes of the young. Journal of Clinical Endocrinology & Metabolism 93: 3505-3509.

Haldorsen IS, Vesterhus M, Ræder H, Jensen DK, Søvik O, Molven A & Njølstad PR (2008). Lack of pancreatic body and tail in HNF1B mutation carriers. Diabetic Medicine 25: 782-787.

Vesterhus M, Ræder H, Johansson S, Molven A & Njølstad PR (2008). Pancreatic exocrine dysfunction in maturity-onset diabetes of the young type 3. Diabetes Care 31: 306-310.

Ræder H, Haldorsen IS, Ersland L, Grüner R, Taxt T, Søvik O, Molven A & Njølstad PR (2007). Pancreatic lipomatosis is a structural marker in non-diabetic children with mutations in carboxyl-ester lipase. Diabetes 56: 444-449.

Ræder H, Johansson S, Holm PI, Haldorsen IS, Mas E, Sbarra V, Nermoen I, Eide SÅ, Grevle L,  Bjørkhaug L, Sagen JV, Aksnes L, Søvik O, Lombardo D, Molven A & Njølstad PR (2006). Mutations in the CEL VNTR cause a syndrome of diabetes and pancreatic exocrine dysfunction. Nature Genetics 38: 54-62.