KRAS mutation analysis by droplet digital PCR of duodenal juice from patients with MODY8 and other pancreatic diseases

Background Maturity-onset diabetes of the young type 8 (MODY8 or CEL-MODY) is an inherited pancreatic disease characterized by chronic inflammation of the pancreas and diabetes. It is not known whether MODY8 patients have increased risk for developing pancreatic cancer. We investigated KRAS mutation load in duodenal juice from MODY8 patients, comparing with other groups of pancreatic disease. Methods Droplet digital PCR (ddPCR) was used to detect KRAS codon 12/13/61 mutations in duodenal juice sampled from 11 MODY8 patients, nine healthy subjects and 100 patients clinically investigated due to suspected pancreatic disease. Results KRAS mutations were detected in 4/11 patients with MODY8 (36%), 1/9 healthy subjects (11%), 15/44 patients with chronic pancreatitis (CP, 34%), 3/5 patients with pancreatic ductal adenocarcinoma (PDAC, 60%), 3/20 patients with acute pancreatitis (15%), 0/13 patients with other pancreatic disorders and 2/18 patients with nonpancreatic gastrointestinal disease (11%). Of the 28 positive juice samples, 25 (89%) had low-abundance mutations in codons 12/13, with a variant allele frequency (VAF) less than 1%. KRAS-positive patients with MODY8 or CP had significantly lower VAFs than patients with PDAC (Mann-Whitney U test; p = 0.041). Although the overall mutation detection rate was higher for subjects ≥50 years old (26%) than for younger subjects (15%), the difference was not statistically significant. Conclusions KRAS mutations were detectable in duodenal juice from MODY8 patients, but with low abundance and at the same frequency as in CP patients. The discriminative value of the analysis with regard to other pancreatic disease was limited.publishedVersio

MRI adipose tissue segmentation and quantification in R (RAdipoSeg)

Background: Excess adipose tissue is associated with increased cardiovascular and metabolic risk, but the volume of visceral and subcutaneous adipose tissue poses different metabolic risks. MRI with fat suppression can be used to accurately quantify adipose depots. We have developed a new semi-automatic method, RAdipoSeg, for MRI adipose tissue segmentation and quantification in the free and open source statistical software R. Methods: MRI images were obtained from wild-type mice on high- or low-fat diet, and from 20 human subjects without clinical signs of metabolic dysfunction. For each mouse and human subject, respectively, 10 images were segmented with RAdipoSeg and with the commercially available software SliceOmatic. Jaccard difference, relative volume difference and Spearman’s rank correlation coefficients were calculated for each group. Agreement between the two methods were analysed with Bland–Altman plots. Results: RAdipoSeg performed similarly to the commercial software. The mean Jaccard differences were 10–29% and the relative volume differences were below ( ±) 20%. Spearman’s rank correlation coefficient gave p-values below 0.05 for both mouse and human images. The Bland–Altman plots indicated some systematic and proporitional bias, which can be countered by the flexible nature of the method. Conclusion: RAdipoSeg is a reliable and low cost method for fat segmentation in studies of mice and humans.publishedVersio

Fucosylated AGP glycopeptides as biomarkers of HNF1A-Maturity onset diabetes of the young

Aims: We previously demonstrated that antennary fucosylated N-glycans on plasma proteins are regulated by HNF1A and can identify cases of Maturity-Onset Diabetes of the Young caused by HNF1A variants (HNF1A-MODY). Based on literature data, we further postulated that N-glycans with best diagnostic value mostly originate from alpha-1-acid glycoprotein (AGP). In this study we analyzed fucosylation of AGP in subjects with HNF1A-MODY and other types of diabetes aiming to evaluate its diagnostic potential. Methods: A recently developed LC-MS method for AGP N-glycopeptide analysis was utilized in two independent cohorts: a) 466 subjects with different diabetes subtypes to test the fucosylation differences, b) 98 selected individuals to test the discriminative potential for pathogenic HNF1A variants. Results: Our results showed significant reduction in AGP fucosylation associated to HNF1A-MODY when compared to other diabetes subtypes. Additionally, ROC curve analysis confirmed significant discriminatory potential of individual fucosylated AGP glycopeptides, where the best performing glycopeptide had an AUC of 0.94 (95% CI 0.90–0.99). Conclusions: A glycopeptide based diagnostic tool would be beneficial for patient stratification by providing information about the functionality of HNF1A. It could assist the interpretation of DNA sequencing results and be a useful addition to the differential diagnostic process.publishedVersio

Two New Mutations in the CEL Gene Causing Diabetes and Hereditary Pancreatitis : How to Correctly Identify MODY8 Cases

Context Maturity onset diabetes of the young, type 8 (MODY8) is associated with mutations in the CEL gene, which encodes the digestive enzyme carboxyl ester lipase. Several diabetes cases and families have in recent years been attributed to mutations in CEL without any functional or clinical evidence provided. Objective To facilitate correct MODY8 diagnostics, we screened 2 cohorts of diabetes patients and delineated the phenotype. Methods Young, lean Swedish and Finnish patients with a diagnosis of type 2 diabetes (352 cases, 406 controls) were screened for mutations in the CEL gene. We also screened 58 Czech MODY cases who had tested negative for common MODY genes. For CEL mutation-positive subjects, family history was recorded, and clinical investigations and pancreatic imaging performed. Results Two cases (1 Swedish and 1 Czech) with germline mutation in CEL were identified. Clinical and radiological investigations of these 2 probands and their families revealed dominantly inherited insulin-dependent diabetes, pancreatic exocrine dysfunction, and atrophic pancreas with lipomatosis and cysts. Notably, hereditary pancreatitis was the predominant phenotype in 1 pedigree. Both families carried single-base pair deletions in the proximal part of the CEL variable number of tandem repeat (VNTR) region in exon 11. The mutations are predicted to lead to aberrant protein tails that make the CEL protein susceptible to aggregation. Conclusion The diagnosis of MODY8 requires a pancreatic exocrine phenotype and a deletion in the CEL VNTR in addition to dominantly inherited diabetes. CEL screening may be warranted also in families with hereditary pancreatitis of unknown genetic etiology.Peer reviewe

Characterisation of HNF1A variants in paediatric diabetes in Norway using functional and clinical investigations to unmask phenotype and monogenic diabetes

Aims/hypothesis Correctly diagnosing MODY is important, as individuals with this diagnosis can discontinue insulin injections; however, many people are misdiagnosed. We aimed to develop a robust approach for determining the pathogenicity of variants of uncertain significance in hepatocyte nuclear factor-1 alpha (HNF1A)-MODY and to obtain an accurate estimate of the prevalence of HNF1A-MODY in paediatric cases of diabetes. Methods We extended our previous screening of the Norwegian Childhood Diabetes Registry by 830 additional samples and comprehensively genotyped HNF1A variants in autoantibody-negative participants using next-generation sequencing. Carriers of pathogenic variants were treated by local healthcare providers, and participants with novel likely pathogenic variants and variants of uncertain significance were enrolled in an investigator-initiated, non-randomised, open-label pilot study (ClinicalTrials.gov registration no. NCT04239586). To identify variants associated with HNF1A-MODY, we functionally characterised their pathogenicity and assessed the carriers’ phenotype and treatment response to sulfonylurea. Results In total, 615 autoantibody-negative participants among 4712 cases of paediatric diabetes underwent genetic sequencing, revealing 19 with HNF1A variants. We identified nine carriers with novel variants classified as variants of uncertain significance or likely to be pathogenic, while the remaining ten participants carried five pathogenic variants previously reported. Of the nine carriers with novel variants, six responded favourably to sulfonylurea. Functional investigations revealed their variants to be dysfunctional and demonstrated a correlation with the resulting phenotype, providing evidence for reclassifying these variants as pathogenic. Conclusions/interpretation Based on this robust classification, we estimate that the prevalence of HNF1A-MODY is 0.3% in paediatric diabetes. Clinical phenotyping is challenging and functional investigations provide a strong complementary line of evidence. We demonstrate here that combining clinical phenotyping with functional protein studies provides a powerful tool to obtain a precise diagnosis of HNF1A-MODY.publishedVersio

Structural imaging findings are related to clinical complications in chronic pancreatitis

Background/objectives: Structural pancreatic changes and complications related to chronic pancreatitis are well described, but little is known about their relationship. We aimed to explore the associations between pancreatic morphology and clinical complications in a large chronic pancreatitis cohort. Methods: The Scandinavian Baltic Pancreatic Club database collects registrations on patients with definite or probable chronic pancreatitis according to the M-ANNHEIM diagnostic criteria. In this cross-sectional study, we used multivariate logistic regression analyses to evaluate whether imaging-based structural pancreatic changes were associated with common clinical complications. We adjusted for sex, age, disease duration, current alcohol abuse and current smoking. Results: We included 742 patients with a mean age of 55 years. Among these, 68% were males, 69% had pancreatic exocrine insufficiency, 35% had diabetes, 12% were underweighted and 68% reported abdominal pain. Main pancreatic duct obstruction, severe (i.e. more than 14) calcifications, pancreatic atrophy and parenchymal changes throughout the entire pancreas (continuous organ involvement) were positively associated with pancreatic exocrine insufficiency. Continuous organ involvement and pseudocysts were positively and negatively associated with diabetes, respectively. Pancreatic atrophy and severe calcifications were positively associated with underweight, and severe calcifications were negatively associated with pain. Conclusions: This study shows independent associations between distinct structural changes on pancreatic imaging and clinical complications in chronic pancreatitis. Pancreatic atrophy, severe calcifications and continuous organ involvement may be of particular clinical relevance, and these findings should motivate monitoring of pancreatic function and nutritional status.publishedVersio

Pancreatic enzyme treatment in chronic pancreatitis : Quality of management and adherence to guidelines–A cross-sectional observational study

Objectives: Pancreatic exocrine insufficiency (PEI) is a common complication in patients with chronic pancreatitis (CP), leading to increased morbidity and mortality if not treated adequately. Pancreatic enzyme replacement therapy|pancreas enzyme replacement therapy (PERT) is the cornerstone in treatment of patients with PEI. In the present study, we use data from the Scandinavian Baltic Pancreatic Club database to examine adherence of PERT according to United European Gastroenterology evidence-based guidelines treatment of CP. Patients and methods: Patients with definitive or probable CP according to M-ANNHEIM diagnostic criteria were included. We collected information on exposures, exocrine function, intake of pancreatic enzymes, and markers of nutrition. Fecal elastase <200 μg/g was defined as a marker for PEI. Enzyme replacement therapy of 100,000 lipase units or more was defined as adequate treatment. Results: We included 1006 patients from 8 centers in five countries. Sixty-four percent of the patients were correctly treated. Twenty-five per cent of PEI patients were not taking enzymes at all, and 20% of PEI patients were undertreated with insufficient PERT doses according to the guidelines. Fourteen percent of patients with sufficient pancreatic function were receiving enzymes despite normal exocrine pancreatic function. There were center differences. Current smoking was associated with lack of treatment and alcohol abuse was associated with under-treatment. There were no associations between “no treatment” or “under-treatment” for underweight or vitamin D deficiency. Conclusion: In our CP expert centers, the adherence to guidelines for enzyme treatment is insufficient. Both patient factors and center differences have influence on treatment adherence.publishedVersionPeer reviewe

Novel endoscopic and MRI-based methods for evaluating exocrine pancreatic function in pancreatitis and monogenic forms of diabetes

Background: Monogenic diabetes (Maturity onset diabetes in the young, MODY) are autosomal dominantly inherited diabetes syndromes characterized by diabetes due to beta cell dysfunction, with typical onset of diabetes before 25 years of age. Two MODY subtypes, HNF1B-MODY and CEL-MODY, have been associated with exocrine pancreatic dysfunction. Assessment of exocrine pancreatic function is a challenge due to few available tests with acceptable feasibility and diagnostic value. Aims: In the present study we wanted to evaluate two novel methods for measuring pancreatic exocrine function; a rapid endoscopic secretin test and a dynamic magnetic resonance imaging (MRI) based protocol. We further wanted to use these two methods to assess the degree and nature of exocrine pancreatic dysfunction in CELMODY and HNF1B-MODY. Materials and methods: We recruited 52 consecutive patients with suspected chronic pancreatitis, 23 patients with CEL-MODY and 8 patients with HNF1B-MODY. Suspected chronic pancreatitis patients underwent the endoscopic procedure only, while MODY patients were offered endoscopy and MRI procedure. In addition, 25 healthy controls underwent endoscopy and 20 healthy controls underwent the MRI protocol. In patients with suspected chronic pancreatitis, a renowned multimodal clinical score was used as reference standard. In MODY patients results from the examinations were compared to nutritional status as achieved from patient records before any treatment with pancreatic enzyme supplements. The endoscopic procedure started 30 minutes after secretin stimulation, with 15 minutes collection of duodenal juice. Duodenal juice was analyzed for bicarbonate in chronic pancreatitis patients, and for bicarbonate and digestive enzyme activities in MODY-patients and healthy controls. The MRI protocol consisted of anatomical imaging, followed by dynamic imaging before and after secretin stimulation. The dynamic series consisted of repeated duodenal fluid volume quantification with magnetic resonance cholangiopancreaticography (MRCP) and measuring apparent diffusion coefficient (ADC) in pancreatic tissue using diffusion-weighted imaging. Results: Using bicarbonate as diagnostic marker, the rapid endoscopic secretin test had acceptable diagnostic value in detecting chronic pancreatitis, and performed significantly better than fecal elastase 1. In healthy controls, increase in secretin stimulated duodenal fluid volumes correlated well with changes in ADC after secretin stimulation. In CEL-MODY patients we found moderately low bicarbonate levels and reduced pancreatic fluid output, and severely reduced digestive enzyme activity levels compared to controls. With exception from low levels of vitamin E, CEL-MODY patients revealed no signs of malnutrition. In HNF1B-MODY patients we found moderately reduced bicarbonate levels, reduced pancreatic fluid output and moderately reduced levels of digestive enzyme activities compared to controls. Pancreatic gland volumes were small in all but one HNF1B-MODY patients, but pancreatic volume output per gland size was increased. Conclusions: Both rapid endoscopic secretin test and the MRI protocol are feasible and well tolerated examination modalities reflecting pancreatic exocrine function. CEL-MODY patients have moderately reduced ductal and severely reduced acinar pancreatic function, but compensated nutritional status. HNF1B-MODY patients have moderately reduced ductal and acinar pancreatic function, partly compensated by hypersecretion from a hypoplastic pancreas

Ultrasound echo-intensity predicts severe Pancreatic affection in cystic fibrosis patients

Background: Pancreatic destruction affects the majority of patients with cystic fibrosis. We aimed to relate ultrasound findings to exocrine pancreatic function and cystic fibrosis genotype. Methods: Patients with cystic fibrosis and a matched group of healthy controls were included. We performed transabdominal ultrasound, and recorded echo intensities of the pancreas and parenchymal characteristics according to endoscopic ultrasound based Rosemont criteria. Results: We included 39 patients and 29 healthy controls. The cystic fibrosis patients were grouped according to exocrine pancreatic function; Cystic fibrosis, insufficient (n = 20) and sufficient (n = 19). Echo intensity measures and visual score demonstrated hyper-echogenicity in the pancreas insufficient group compared to the pancreas sufficient groups (p<0.001). Ductal and parenchymal changes were not prevalent in any of the groups. Conclusion: The hyper-echoic pancreas was the most frequent ultrasonographic finding in exocrine pancreas insufficient cystic fibrosis patients. Pancreatic echo levels correlated to pancreatic phenotype