The histopathology of PRSS1 hereditary pancreatitis. Am J Surg Pathol. 2014;38:346-353. [PMID: 24525505 DOI: 10.1097/pas.0000000000000164]

Heterozygous Spink1 c.194+2T>C mutation promotes chronic pancreatitis after acute attack in mice

BACKGROUND & AIMS

Mutations in genes, including serine protease inhibitor Kazal-type 1 (SPINK1), influence disease progression following sentinel acute pancreatitis event (SAPE) attacks. SPINK1 c.194+2T > C intron mutation is one of the main mutants of SPINK1，which leads to the impairment of SPINK1 function by causing skipping of exon 3. Research on the pathogenesis of SAPE attacks would contribute to the understanding of the outcomes of acute pancreatitis. Therefore, the aim of the study was to clarify the role of SPINK1 c.194+2T > C mutation in the CP progression after an AP attack.

METHODS

SAPE attacks were induced in wildtype and SPINK mutant (Spink1 c.194+2T > C) mice by cerulein injection. The mice were sacrificed at 24 h, 14 d, 28 d, and 42 d post-SAPE. Data-independent acquisition (DIA) proteomic analysis was performed for the identification of differentially expressed protein in the pancreatic tissues. Functional analyses were performed using THP-1 and HPSCs.

RESULTS

Following SAPE attack, the Spink1 c.194+2T > C mutant mice exhibited a more severe acute pancreatitis phenotype within 24 h. In the chronic phase, the chronic pancreatitis phenotype was more severe in the Spink1 c.194+2T > C mutant mice after SAPE. Proteomic analysis revealed elevated IL-33 level in Spink1 c.194+2T > C mutant mice. Further in vitro analyses revealed that IL-33 induced M2 polarization of macrophages and activation of pancreatic stellate cells.

CONCLUSION

Spink1 c.194+2T > C mutation plays an important role in the prognosis of patients following SAPE. Heterozygous Spink1 c.194+2T > C mutation promotes the development of chronic pancreatitis after an acute attack in mice through elevated IL-33 level and the induction of M2 polarization in coordination with pancreatic stellate cell activation.

Precursor lesions in familial and hereditary pancreatic cancer

Infiltrating ductal adenocarcinoma of the pancreas, referred to here as "pancreatic cancer," is one of the deadliest of all of the solid malignancies. The five-year survival rate in the United States for individuals diagnosed today with pancreatic cancer is a dismal 12%. Many invasive cancers, including pancreatic cancer, however, arise from histologically and genetically well-characterized precursor lesions, and these precancers are curable. Precursor lesions therefore are an attractive target for early detection and treatment. This is particularly true for individuals with an increased risk of developing invasive cancer, such as individuals with a strong family history of pancreatic cancer, and individuals with a germline variant known to increase the risk of developing pancreatic cancer. There is therefore a need to understand the precursor lesions that can give rise to invasive pancreatic cancer in these individuals.

Identification of Potential Hub Genes Related to Acute Pancreatitis and Chronic Pancreatitis via Integrated Bioinformatics Analysis and In Vitro Analysis

Acute pancreatitis (AP) and chronic pancreatitis (CP) are considered to be two separate pancreatic diseases in most studies, but some clinical retrospective analyses in recent years have found some degree of correlation between the two in actual treatment, however, the exact association is not clear. In this study, bioinformatics analysis was utilized to examine microarray sequencing data in mice, with the aim of elucidating the critical signaling pathways and genes involved in the progression from AP to CP. Differential gene expression analyses on murine transcriptomes were conducted using the R programming language and the R/Bioconductor package. Additionally, gene network analysis was performed using the STRING database to predict correlations among genes in the context of pancreatic diseases. Functional enrichment and gene ontology pathways common to both diseases were identified using Metascape. The hub genes were screened in the cytoscape algorithm, and the mRNA levels of the hub genes were verified in mice pancreatic tissues of AP and CP. Then the drugs corresponding to the hub genes were obtained in the drug-gene relationship. A set of hub genes, including Jun, Cd44, Epcam, Spp1, Anxa2, Hsp90aa1, and Cd9, were identified through analysis, demonstrating their pivotal roles in the progression from AP to CP. Notably, these genes were found to be enriched in the Helper T-cell factor (Th17) signaling pathway. Up-regulation of these genes in both AP and CP mouse models was validated through quantitative real-time polymerase chain reaction (qRT-PCR) results. The significance of the Th17 signaling pathway in the transition from AP to CP was underscored by our findings. Specifically, the essential genes driving this progression were identified as Jun, Cd44, Epcam, Spp1, Anxa2, Hsp90aa1, and Cd9. Crucial insights into the molecular mechanisms underlying pancreatitis progression were provided by this research, offering promising avenues for the development of targeted therapeutic interventions.

Classification of PRSS1 variants responsible for chronic pancreatitis: An expert perspective from the Franco-Chinese GREPAN study group

BACKGROUND

PRSS1 was the first reported chronic pancreatitis (CP) gene. The existence of both gain-of-function (GoF) and gain-of-proteotoxicity (GoP) pathological PRSS1 variants, together with the fact that PRSS1 variants have been identified in CP subtypes spanning the range from monogenic to multifactorial, has made the classification of PRSS1 variants very challenging.

METHODS

All currently reported PRSS1 variants (derived primarily from two databases) were manually reviewed with respect to their clinical genetics, functional analysis and population allele frequency. They were classified by variant type and pathological mechanism within the framework of our recently proposed ACMG/AMP guidelines-based seven-category system.

RESULTS

The total number of distinct germline PRSS1 variants included for analysis was 100, comprising 3 copy number variants (CNVs), 12 5' and 3' variants, 19 intronic variants, 5 nonsense variants, 1 frameshift deletion variant, 6 synonymous variants, 1 in-frame duplication, 3 gene conversions and 50 missense variants. Based upon a combination of clinical genetic and functional analysis, population data and in silico analysis, we classified 26 variants (all 3 CNVs, the in-frame duplication, all 3 gene conversions and 19 missense) as "pathogenic", 3 variants (missense) as "likely pathogenic", 5 variants (four missense and one promoter) as "predisposing", 13 variants (all missense) as "unknown significance", 2 variants (missense) as "likely benign", and all remaining 51 variants as "benign".

CONCLUSIONS

We describe an expert classification of the 100 PRSS1 variants reported to date. The results have immediate implications for reclassifying many ClinVar-registered PRSS1 variants as well as providing optimal guidelines/standards for reporting PRSS1 variants.

Intrapancreatic fat, pancreatitis, and pancreatic cancer

Pancreatic cancer is typically detected at an advanced stage, and is refractory to most forms of treatment, contributing to poor survival outcomes. The incidence of pancreatic cancer is gradually increasing, linked to an aging population and increasing rates of obesity and pancreatitis, which are risk factors for this cancer. Sources of risk include adipokine signaling from fat cells throughout the body, elevated levels of intrapancreatic intrapancreatic adipocytes (IPAs), inflammatory signals arising from pancreas-infiltrating immune cells and a fibrotic environment induced by recurring cycles of pancreatic obstruction and acinar cell lysis. Once cancers become established, reorganization of pancreatic tissue typically excludes IPAs from the tumor microenvironment, which instead consists of cancer cells embedded in a specialized microenvironment derived from cancer-associated fibroblasts (CAFs). While cancer cell interactions with CAFs and immune cells have been the topic of much investigation, mechanistic studies of the source and function of IPAs in the pre-cancerous niche are much less developed. Intriguingly, an extensive review of studies addressing the accumulation and activity of IPAs in the pancreas reveals that unexpectedly diverse group of factors cause replacement of acinar tissue with IPAs, particularly in the mouse models that are essential tools for research into pancreatic cancer. Genes implicated in regulation of IPA accumulation include KRAS, MYC, TGF-β, periostin, HNF1, and regulators of ductal ciliation and ER stress, among others. These findings emphasize the importance of studying pancreas-damaging factors in the pre-cancerous environment, and have significant implications for the interpretation of data from mouse models for pancreatic cancer.

Fatty change of the pancreas: the Pandora's box of pancreatology

Prevention of common diseases of the pancreas or interception of their progression is as attractive in theory as it is elusive in practice. The fundamental challenge has been an incomplete understanding of targets coupled with a multitude of intertwined factors that are associated with the development of pancreatic diseases. Evidence over the past decade has shown unique morphological features, distinctive biomarkers, and complex relationships of intrapancreatic fat deposition. Fatty change of the pancreas has also been shown to affect at least 16% of the global population. This knowledge has solidified the pivotal role of fatty change of the pancreas in acute pancreatitis, chronic pancreatitis, pancreatic cancer, and diabetes. The pancreatic diseases originating from intrapancreatic fat (PANDORA) hypothesis advanced in this Personal View cuts across traditional disciplinary boundaries with a view to tackling these diseases. New holistic understanding of pancreatic diseases is well positioned to propel pancreatology through lasting research breakthroughs and clinical advances.

Acinar cells and the development of pancreatic fibrosis

Pancreatic fibrosis is caused by excessive deposition of extracellular matrixes of collagen and fibronectin in the pancreatic tissue as a result of repeated injury often seen in patients with chronic pancreatic diseases. The most common causative conditions include inborn errors of metabolism, chemical toxicity and autoimmune disorders. Its pathophysiology is highly complex, including acinar cell injury, acinar stress response, duct dysfunction, pancreatic stellate cell activation, and persistent inflammatory response. However, the specific mechanism remains to be fully clarified. Although the current therapeutic strategies targeting pancreatic stellate cells show good efficacy in cell culture and animal models, they are not satisfactory in the clinic. Without effective intervention, pancreatic fibrosis can promote the transformation from pancreatitis to pancreatic cancer, one of the most lethal malignancies. In the normal pancreas, the acinar component accounts for 82% of the exocrine tissue. Abnormal acinar cells may activate pancreatic stellate cells directly as cellular source of fibrosis or indirectly via releasing various substances and initiate pancreatic fibrosis. A comprehensive understanding of the role of acinar cells in pancreatic fibrosis is critical for designing effective intervention strategies. In this review, we focus on the role of and mechanisms underlying pancreatic acinar injury in pancreatic fibrosis and their potential clinical significance.

Familial pancreatic cancer

Pancreatic cancer (PC) carries a poor prognosis with an overall 5-year survival of less than 10%. Early diagnosis, though cumbersome, is essential to allow complete surgical resection. Therefore, primary and secondary prevention are critical to reduce the incidence and to potentially prevent mortality. Given a relatively low lifetime risk of developing PC, identification of high-risk individuals is crucial to allow identification of pre-malignant lesions and small, localized tumors. Although 85-90% of PC cases are sporadic, we could consider risk stratification for the 5-10% of patients with a family history and the 3-5% of cases due to inherited genetic syndromes. These high-risk populations should be considered for screening and surveillance of PC. MRI/MRCP and EUS are the preferred modalities, due to their high sensitivity in lesion detection. Surveillance should be personalized, considering genetics and family history, and assessment of risk factors that may increase cancer risk. Screening programs should be limited to tertiary referral center, with high-volumes and adequate facilities to manage these patients.

The genetic risk factor CEL-HYB1 causes proteotoxicity and chronic pancreatitis in mice

BACKGROUND & AIMS

The CEL gene encodes the digestive enzyme carboxyl ester lipase. CEL-HYB1, a hybrid allele of CEL and its adjacent pseudogene CELP, is a genetic variant suggested to increase the risk of chronic pancreatitis (CP). Our aim was to develop a mouse model for CEL-HYB1 that enables studies of pancreatic disease mechanisms.

METHODS

We established a knock-in mouse strain where the variable number of tandem repeat (VNTR) region of the endogenous mouse Cel gene was substituted with the mutated VNTR of the human CEL-HYB1 allele. Heterozygous and homozygous Cel-HYB1 mice and littermate wildtype controls were characterized with respect to pancreatic pathology and function.

RESULTS

We successfully constructed a mouse model with pancreatic expression of a humanized CEL-HYB1 protein. The Cel-HYB1 mice spontaneously developed features of CP including inflammation, acinar atrophy and fatty replacement, and the phenotype became more pronounced as the animals aged. Moreover, Cel-HYB1 mice were normoglycemic at age 6 months, whereas at 12 months they exhibited impaired glucose tolerance. Immunostaining of pancreatic tissue indicated the formation of CEL protein aggregates, and electron microscopy showed dilated endoplasmic reticulum. Upregulation of the stress marker BiP/GRP78 was seen in pancreatic parenchyma obtained both from Cel-HYB1 animals and from a human CEL-HYB1 carrier.

CONCLUSIONS

We have developed a new mouse model for CP that confirms the pathogenicity of the human CEL-HYB1 variant. Our findings place CEL-HYB1 in the group of genes that increase CP risk through protein misfolding-dependent pathways.

Quantitative MRI of chronic pancreatitis: results from a multi-institutional prospective study, magnetic resonance imaging as a non-invasive method for assessment of pancreatic fibrosis (MINIMAP)

PURPOSE

To determine if quantitative MRI techniques can be helpful to evaluate chronic pancreatitis (CP) in a setting of multi-institutional study.

METHODS

This study included a subgroup of participants (n = 101) enrolled in the Prospective Evaluation of Chronic Pancreatitis for Epidemiologic and Translational Studies (PROCEED) study (NCT03099850) from February 2019 to May 2021. MRI was performed on 1.5 T using Siemens and GE scanners at seven clinical centers across the USA. Quantitative MRI parameters of the pancreas included T1 relaxation time, extracellular volume (ECV) fraction, apparent diffusion coefficient (ADC), and fat signal fraction. We report the diagnostic performance and mean values within the control (n = 50) and CP (n = 51) groups. The T1, ECV and fat signal fraction were combined to generate the quantitative MRI score (Q-MRI).

RESULTS

There was significantly higher T1 relaxation time; mean 669 ms (± 171) vs. 593 ms (± 82) (p = 0.006), ECV fraction; 40.2% (± 14.7) vs. 30.3% (± 11.9) (p < 0.001), and pancreatic fat signal fraction; 12.2% (± 5.5) vs. 8.2% (± 4.4) (p < 0.001) in the CP group compared to controls. The ADC was similar between groups (p = 0.45). The AUCs for the T1, ECV, and pancreatic fat signal fraction were 0.62, 0.72, and 0.73, respectively. The composite Q-MRI score improved the diagnostic performance (cross-validated AUC: 0.76).

CONCLUSION

Quantitative MR parameters evaluating the pancreatic parenchyma (T1, ECV fraction, and fat signal fraction) are helpful in the diagnosis of CP. A Q-MRI score that combines these three MR parameters improves diagnostic performance. Further studies are warranted with larger study populations including patients with acute and recurrent acute pancreatitis and longitudinal follow-ups.

Total Pancreatectomy with Islet Autotransplantation: New Insights on the Pathology and Pathogenesis of Chronic Pancreatitis from Tissue Research

Total pancreatectomy with islet autotransplantation (TPIAT) is a surgical procedure undertaken in some patients with severe pain or disability from recurrent acute and chronic pancreatitis (CP). TPIAT provides a rare opportunity to study human pancreas tissue from patients affected with pancreatitis, and particularly from patients with genetic forms of pancreatitis. Research to date suggests distinct histopathology and potentially differential pathophysiology of distinct etiologies of CP. Histopathology specimens have helped better define the success and limitations of clinical diagnostic imaging tools, such as magnetic retrograde cholangiopancreatography and endoscopic ultrasound.

St13 protects against disordered acinar cell arachidonic acid pathway in chronic pancreatitis

BACKGROUND

Early diagnosis and treatment of chronic pancreatitis (CP) are limited. In this study, St13, a co-chaperone protein, was investigated whether it constituted a novel regulatory target in CP. Meanwhile, we evaluated the value of micro-PET/CT in the early diagnosis of CP.

METHODS

Data from healthy control individuals and patients with alcoholic CP (ACP) or non-ACP (nACP) were analysed. PRSS1 transgenic mice (PRSS1^Tg) were treated with ethanol or caerulein to mimic the development of ACP or nACP, respectively. Pancreatic lipid metabolite profiling was performed in human and PRSS1^Tg model mice. The potential functions of St13 were investigated by crossing PRSS1^Tg mice with St13^-/- mice via immunoprecipitation and lipid metabolomics. Micro-PET/CT was performed to evaluate pancreatic morphology and fibrosis in CP model.

RESULTS

The arachidonic acid (AA) pathway ranked the most commonly dysregulated lipid pathway in ACP and nACP in human and mice. Knockout of St13 exacerbated fatty replacement and fibrosis in CP model. Sdf2l1 was identified as a binding partner of St13 as it stabilizes the IRE1α-XBP1s signalling pathway, which regulates COX-2, an important component in AA metabolism. Micro-PET/CT with ⁶⁸Ga-FAPI-04 was useful for evaluating pancreatic morphology and fibrosis in CP model mice 2 weeks after modelling.

CONCLUSION

St13 is functionally activated in acinar cells and protects against the cellular characteristics of CP by binding Sdf2l1, regulating AA pathway. ⁶⁸Ga-FAPI-04 PET/CT may be a very valuable approach for the early diagnosis of CP. These findings thus provide novel insights into both diagnosis and treatment of CP.

Inflammatory and tumor-like lesions of the pancreas

Inflammatory/tumor-like lesions of the pancreas represent a heterogeneous group of diseases that can variably involve the pancreatic gland determining different signs and symptoms. In the category of inflammatory/tumor-like lesions of the pancreas, the most important entities are represented by chronic pancreatitis, which includes alcoholic, obstructive and hereditary pancreatitis, paraduodenal (groove) pancreatitis, autoimmune pancreatitis, lymphoepithelial cyst, pancreatic hamartoma and intrapancreatic accessory spleen. An in-depth knowledge of such diseases is essential, since they can cause severe morbidity and may represent a potential life-threatening risk for patients. Furthermore, in some cases the differential diagnosis with malignant tumors may be challenging. Herein we provide a general overview of all these categories, with the specific aim of highlighting their most important clinic-pathological hallmarks to be used in routine diagnostic activities and clinical practice.

Pancreas in Hereditary Syndromes: Cross-sectional Imaging Spectrum

A wide spectrum of hereditary syndromes predispose patients to distinct pancreatic abnormalities, including cystic lesions, recurrent pancreatitis, ductal adenocarcinoma, nonductal neoplasms, and parenchymal iron deposition. While pancreatic exocrine insufficiency and recurrent pancreatitis are common manifestations in cystic fibrosis and hereditary pancreatitis, pancreatic cysts are seen in von Hippel-Lindau disease, cystic fibrosis, autosomal dominant polycystic kidney disease, and McCune-Albright syndrome. Ductal adenocarcinoma can be seen in many syndromes, including Peutz-Jeghers syndrome, familial atypical multiple mole melanoma syndrome, Lynch syndrome, hereditary breast and ovarian cancer syndrome, Li-Fraumeni syndrome, and familial pancreatic cancer syndrome. Neuroendocrine tumors are commonly seen in multiple endocrine neoplasia type 1 syndrome and von Hippel-Lindau disease. Pancreatoblastoma is an essential component of Beckwith-Wiedemann syndrome. Primary hemochromatosis is characterized by pancreatic iron deposition. Pancreatic pathologic conditions associated with genetic syndromes exhibit characteristic imaging findings. Imaging plays a pivotal role in early detection of these conditions and can positively affect the clinical outcomes of those at risk for pancreatic malignancies. Awareness of the characteristic imaging features, imaging-based screening protocols, and surveillance guidelines is crucial for radiologists to guide appropriate patient management. ^©RSNA, 2021.

Histopathology of SPINK-1 Hereditary Pancreatitis

Hereditary pancreatitis is a rare form of recurrent acute pancreatitis that typically has an onset in early adulthood. We report a rare case of hereditary pancreatitis in an individual with a serine protease inhibitor Kazal type 1 (SPINK1) mutation. Histologically the pancreas showed features of chronic pancreatitis with variable fibrosis, acinar destruction, and prominent inspissated secretions within the pancreatic ducts. Additionally, focal areas of low-grade pancreatic intraepithelial neoplasia (PanIN) were present. Although the histopathology of common gene mutations resulting in hereditary pancreatitis have been well described, the histopathology of pancreatitis secondary to SPINK1 mutation has been described in only one previous study.

The histopathology of SPINK1-associated chronic pancreatitis

BACKGROUND

The identification of genetic risk factors for chronic pancreatitis, such as PRSS1, CFTR and SPINK1, provides the opportunity to define key pathologic hallmarks and etiologic-specific changes. For example, pancreata from PRSS1 and CFTR patients exhibit progressive lipomatous atrophy without significant fibrosis. Considering the pathology of SPINK1-associated pancreatitis is ill-defined, we examined the pancreata of SPINK1 patients with chronic pancreatitis.

METHODS

Histologic sections after total pancreatectomy with islet autotransplantation and associated clinicopathologic data were collected from 28 patients with SPINK1 germline alterations. Clinical findings, germline data, anatomic anomalies and pathologic findings were descriptively evaluated.

RESULTS

Patients ranged in age from 5 to 48 years (median, 21.6 years) with abdominal pain between 2 and 25 years (median, 5.8 years). Most patients were SPINK1 heterozygous and 14 (50%) had co-occurring CFTR (n = 12) and CTRC (n = 2) mutations. Other pancreatitis risk factors included anatomic anomalies (n = 9) and tobacco use (n = 1). Overall, 24 (86%) patients had additional pancreatitis-associated germline alterations, SPINK1 homozygosity, anatomic anomalies or environmental factors. Examination of pancreata revealed a sequential pattern of exocrine parenchymal loss and replacement by prominent fibrosis, dependent on the duration of abdominal pain. No malignancies were identified, but low-grade pancreatic intraepithelial neoplasia was present for 2 cases.

CONCLUSIONS

Within this descriptive study, SPINK1-associated pancreatitis is characterized by parenchymal fibrosis and suggests divergent pathophysiologic mechanisms from PRSS1 and CFTR-associated pancreatitis. Moreover, SPINK1 patients frequently had additional etiologic factors that did not impact the development of pancreatic fibrosis and may implicate SPINK1 as a disease modifier gene.

The genetics of ductal adenocarcinoma of the pancreas in the year 2020: dramatic progress, but far to go

The publication of the "Pan-Cancer Atlas" by the Pan-Cancer Analysis of Whole Genomes Consortium, a partnership formed by The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC), provides a wonderful opportunity to reflect on where we stand in our understanding of the genetics of pancreatic cancer, as well as on the opportunities to translate this understanding to patient care. From germline variants that predispose to the development of pancreatic cancer, to somatic mutations that are therapeutically targetable, genetics is now providing hope, where there once was no hope, for those diagnosed with pancreatic cancer.

Pancreatic volume does not correlate with histologic fibrosis in adult patients with recurrent acute and chronic pancreatitis

OBJECTIVES

Reduced pancreatic volume, often referred to as atrophy, is a commonly reported imaging feature of chronic pancreatitis (CP). This study evaluated whether there is an association between pancreatic volume and fibrosis, the criterion standard of CP, in patients undergoing total pancreatectomy with islet autotransplantation (TPIAT) for recurrent acute pancreatitis (RAP) and CP.

METHODS

All adult patients who underwent TPIAT between 2010 and 2019 were categorized into 3 groups: RAP, definite CP and indeterminate CP. Pancreatic volume was calculated by summing up the areas from each thin section of the pancreas on 3D CT imaging. Excisional biopsies of the pancreatic head as well as body/tail region were obtained at the time of TPIAT. Two different fibrosis scores were used for histologic assessment.

RESULTS

A total of 16, 29 and 15 patients underwent TPIAT for RAP, definite CP and indeterminate CP, respectively. The mean pancreatic volumes for patients with RAP, definite CP and indeterminate CP were 65.7 ± 28.5 cc, 54.9 ± 22.9 cc and 61.8 ± 23.6 cc, respectively (p = 0.3). The mean fibrosis scores were significantly higher in patients with definite CP compared to RAP (p < 0.001) and indeterminate CP (p < 0.001). Pancreatic volume was not associated with either fibrosis score after adjusting for age, gender, duration of disease, BMI and diabetes in the multivariable analysis.

CONCLUSIONS

While the fibrosis scores were higher in definite CP compared to both RAP and indeterminate CP, there was no correlation between pancreatic volume and fibrosis. This suggests that atrophy alone cannot be used to diagnose CP.

Trypsin activity governs increased susceptibility to pancreatitis in mice expressing human PRSS1R122H

Currently, an effective targeted therapy for pancreatitis is lacking. Hereditary pancreatitis (HP) is a heritable, autosomal-dominant disorder with recurrent acute pancreatitis (AP) progressing to chronic pancreatitis (CP) and a markedly increased risk of pancreatic cancer. In 1996, mutations in PRSS1 were linked to the development of HP. Here, we developed a mouse model by inserting a full-length human PRSS1R122H gene, the most commonly mutated gene in human HP, into mice. Expression of PRSS1R122H protein in the pancreas markedly increased stress signaling pathways and exacerbated AP. After the attack of AP, all PRSS1R122H mice had disease progression to CP, with similar histologic features as those observed in human HP. By comparing PRSS1R122H mice with PRSS1WT mice, as well as enzymatically inactivated Dead-PRSS1R122H mice, we unraveled that increased trypsin activity is the mechanism for R122H mutation to sensitize mice to the development of pancreatitis. We further discovered that trypsin inhibition, in combination with anticoagulation therapy, synergistically prevented progression to CP in PRSS1R122H mice. These animal models help us better understand the complex nature of this disease and provide powerful tools for developing and testing novel therapeutics for human pancreatitis.

Guidelines on the histopathology of chronic pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and the European Pancreatic Club

BACKGROUND

Chronic pancreatitis is a complex multifactorial fibro-inflammatory disease. Consensus guidelines are needed for the histopathological evaluation of non-autoimmune chronic pancreatitis (CP).

METHODS

An international working group with experts on the histopathology of CP evaluated 15 statements generated from evidence on seven key clinically relevant questions. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the level of evidence available for each statement. To determine the level of agreement, the working group voted on the statements for strength of agreement, using a nine-point Likert scale, and Cronbach's alpha reliability coefficients were calculated.

RESULTS

Strong consensus was obtained for 12 statements relating to all seven key questions including that: the cardinal features of CP are the triad of fibrosis, loss of acinar tissue and duct changes; there are no unique histopathological features that distinguish the different aetiologies of CP; clinical history and laboratory investigations, including genetic testing, are important in establishing the aetiology of CP; there is no reproducible and universally accepted histological grading system for assessing severity of CP, although classification as "mild", "moderate" and "severe" is usually applied; scoring systems for fibrosis are not validated for clinical use; asymptomatic fibrosis is a common finding associated with ageing, and not necessarily evidence of CP; there are no obvious diagnostic macroscopic features of early CP; histopathology is not the gold standard for the diagnosis of CP; and cytology alone is not a reliable method for the diagnosis of CP.

CONCLUSIONS

Cardinal histopathological features of CP are well-defined and internationally accepted and pathological assessment is relevant for the purpose of differential diagnosis with other pancreatic diseases, especially cancer. However, a reliable diagnosis of CP requires integration of clinical, laboratory and imaging features and cannot be made by histology alone.

Pancreatic Fat Infiltration Is Associated with a Higher Risk of Pancreatic Ductal Adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) has a poor survival rate, partly due to delayed diagnosis. Identifying high-risk individuals could lead to early detection and improve survival. A number of risk factors such as alcohol consumption and metabolic syndrome are associated with fatty infiltration of the pancreas. Experimental models show that a fatty pancreas promotes tissue inflammation and fibrosis, which could promote PDAC.

Methods

We conducted a case-control study in a single-university tertiary hospital. Sixty-eight PDAC cases with recent non-contrast computed tomography (CT) and 235 controls were studied. The controls had no history of malignancy and underwent CT colonography for cancer screening in the same period. Pancreatic fat was estimated by calculating pancreatic (P) attenuation, corrected to splenic (S) attenuation, measured in three 1.0-cm² regions of the pancreas. The P.S100 value calculated was used to estimate fatty infiltration of the pancreas (FIP), with a lower P.S100 representing a higher FIP.

Results

The PDAC patients had a lower BMI and a higher rate of type 2 diabetes mellitus. The P.S100 was lower in cases than in controls (86.452 vs. 92.414, p = 4.016e-06), suggesting that FIP is higher with PDAC. The risk of developing PDAC steadily increased significantly for the quartiles with a higher FIP compared to the low FIP quartile. No correlation between BMI and FIP (r = -0.1031179; 95% confidence interval [CI] -0.22267106 to 0.01949092) was found. Adjusting for confounders (age, sex, BMI, and DM), the risk of developing PDAC according to the FIP was estimated to be 3.75 (95% CI 1.9234408-7.993337; p = 0.000171). FIP was stable before and after the diagnosis of PDAC in 9 cases with prior CT scans when no pancreatic tumor was identifiable.

Conclusion

Fatty pancreas is associated with an increased risk of pancreatic cancer. Once confirmed in larger-scale studies, these findings could help to identify at-risk individuals, particularly in high-risk groups such as chronic alcohol consumers.

A preclinical model of chronic pancreatitis driven by trypsinogen autoactivation

Inflammatory diseases of the pancreas have no specific therapy. Discovery of the genetic basis of chronic pancreatitis identified the digestive enzyme trypsin as a therapeutic target. Preclinical testing of trypsin inhibition has been hampered by the lack of animal models. Here we report the T7D23A knock-in mouse, which carries a heterozygous p.D23A mutation in mouse cationic trypsinogen (isoform T7). This trypsinogen mutant autoactivates to trypsin 50-fold faster than wild type. T7D23A mice develop spontaneous acute pancreatitis with edema, necrosis and serum amylase elevation at an early age followed by progressive atrophic chronic pancreatitis with acinar cell loss, fibrosis, dilated ducts and adipose replacement. Markedly elevated trypsin activity is apparent at first signs of pancreatitis and persists into later stages of the disease. This remarkable model provides in vivo proof of concept that trypsinogen autoactivation can drive onset and progression of chronic pancreatitis and therapy should be directed against intra-pancreatic trypsin.

Pancreatic Cancer and Obesity: Molecular Mechanisms of Cell Transformation and Chemoresistance

Cancer and obesity are the two major epidemics of the 21st century. Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of death, with a five-year overall survival rate of only 8%. Its incidence and mortality have increased in recent years, and this cancer type is expected to be among the top five leading causes of cancer-related death by 2030 in the United States (US). In the last three decades, the prevalence of overweight people has boosted with a consequent increase in obesity-related diseases. Considerable epidemiologic evidence correlates overweight and obese conditions to an increased risk of several types of cancer, including PDAC. Besides being a risk factor for multiple metabolic disorders, the tumor-promoting effects of obesity occur at the local level via inflammatory mediators that are associated with adipose inflammation and metabolic or hormones mediators and microbiota dysbiosis. Although an excess of body mass index (BMI) represents the second most modifiable risk factor for PDAC with an increased cancer related-death of more than 20–40%, still little is known about the molecular mechanisms that underlie this strong association. In this review, we focused on the role of obesity as a preventable risk factor of PDAC, discussing the molecular mechanisms linking obesity to cancer initiation and progression. Moreover, we highlighted the role of obesity in defining chemoresistance, showing how a high BMI can actually reduce response to chemotherapy.

Familial Pancreatic Cancer

Familial pancreatic cancer accounts for 10% of all patients with pancreatic cancer. Because the 5-year survival rate of pancreatic cancer is only 7%, screening programs for high-risk individuals are essential and might be advantageous. Pancreatic ductal adenocarcinoma mostly shows symptoms at an advanced state and treatment is not efficient enough to cure most patients. People with hereditary tumor syndromes or their affected relatives can also be included in such screening programs. Besides the collection of data to investigate the background of the disease, these screening programs aim to diagnose and treat precursor lesions so that more dangerous, invasive lesions are prevented. These precursor lesions can be pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. This review summarizes the latest knowledge of pancreatic screening programs, shows the procedure of pancreatic cancer screening, and gives an overview of current guidelines.

Trans-heterozygosity for mutations enhances the risk of recurrent/chronic pancreatitis in patients with Cystic Fibrosis

BACKGROUND

Recurrent (RP) and chronic pancreatitis (CP) may complicate Cystic Fibrosis (CF). It is still unknown if mutations in genes involved in the intrapancreatic activation of trypsin (IPAT) or in the pancreatic secretion pathway (PSP) may enhance the risk for RP/CP in patients with CF.

METHODS

We enrolled: 48 patients affected by CF complicated by RP/CP and, as controls 35 patients with CF without pancreatitis and 80 unrelated healthy subjects. We tested a panel of 8 genes involved in the IPAT, i.e. PRSS1, PRSS2, SPINK1, CTRC, CASR, CFTR, CTSB and KRT8 and 23 additional genes implicated in the PSP.

RESULTS

We found 14/48 patients (29.2%) with mutations in genes involved in IPAT in the group of CF patients with RP/CP, while mutations in such genes were found in 2/35 (5.7%) patients with CF without pancreatitis and in 3/80 (3.8%) healthy subjects (p < 0.001). Thus, we found mutations in 12 genes of the PSP in 11/48 (22.9%) patients with CF and RP/CP. Overall, 19/48 (39.6%) patients with CF and RP/CP showed one or more mutations in the genes involved in the IPAT and in the PSP while such figure was 4/35 (11.4%) for patients with CF without pancreatitis and 11/80 (13.7%) for healthy controls (p < 0.001).

CONCLUSIONS

The trans-heterozygous association between CFTR mutations in genes involved in the pathways of pancreatic enzyme activation and the pancreatic secretion may be risk factors for the development of recurrent or chronic pancreatitis in patients with CF.

Chronic pancreatitis

Chronic pancreatitis is defined as a pathological fibro-inflammatory syndrome of the pancreas in individuals with genetic, environmental and/or other risk factors who develop persistent pathological responses to parenchymal injury or stress. Potential causes can include toxic factors (such as alcohol or smoking), metabolic abnormalities, idiopathic mechanisms, genetics, autoimmune responses and obstructive mechanisms. The pathophysiology of chronic pancreatitis is fairly complex and includes acinar cell injury, acinar stress responses, duct dysfunction, persistent or altered inflammation, and/or neuro-immune crosstalk, but these mechanisms are not completely understood. Chronic pancreatitis is characterized by ongoing inflammation of the pancreas that results in progressive loss of the endocrine and exocrine compartment owing to atrophy and/or replacement with fibrotic tissue. Functional consequences include recurrent or constant abdominal pain, diabetes mellitus (endocrine insufficiency) and maldigestion (exocrine insufficiency). Diagnosing early-stage chronic pancreatitis is challenging as changes are subtle, ill-defined and overlap those of other disorders. Later stages are characterized by variable fibrosis and calcification of the pancreatic parenchyma; dilatation, distortion and stricturing of the pancreatic ducts; pseudocysts; intrapancreatic bile duct stricturing; narrowing of the duodenum; and superior mesenteric, portal and/or splenic vein thrombosis. Treatment options comprise medical, radiological, endoscopic and surgical interventions, but evidence-based approaches are limited. This Primer highlights the major progress that has been made in understanding the pathophysiology, presentation, prevalence and management of chronic pancreatitis and its complications.

Specific Radiological Imaging Findings in Patients With Hereditary Pancreatitis During a Long Follow-up of Disease

OBJECTIVES

Hereditary pancreatitis (HP) is characterized by recurrent episodes of inflammation of the pancreas. Radiological imaging is used to diagnose HP and to monitor complications. The aim of this study was to describe specific imaging findings in HP.

METHODS

We retrospectively collected data of HP patients with serial imaging and reviewed all radiological imaging studies (transabdominal ultrasonography, computed tomography, and magnetic resonance imaging).

RESULTS

We included 15 HP patients, with a mean age of 32.5 years (range, 9-61 years) and mean disease duration of 24.1 years (range, 6-42 years). In total, 152 imaging studies were reviewed. Seventy-three percent of patients had a dilated main pancreatic duct (MPD) (width 3.5-18 mm). The MPD varied in size during disease course, with temporary reduction in diameter after drainage procedures. A severe dilated MPD (>10 mm) often coincided with presence of intraductal calcifications (size, 1-12 mm). In 73% of patients, pancreatic parenchyma atrophy occurred, which did not correlate with presence of exocrine or endocrine insufficiency.

CONCLUSIONS

In HP, the MPD diameter increases with time, mostly without dilated side branches, and is often accompanied by large intraductal calcifications. The size of the MPD is independent of disease state. Atrophy of pancreatic parenchyma is not correlated with exocrine or endocrine insufficiency.

Chronic Pancreatitis

Chronic pancreatitis is a debilitating condition often associated with severe abdominal pain and exocrine and endocrine dysfunction. The underlying cause is multifactorial and involves complex interaction of environmental, genetic, and/or other risk factors. The pathology is dependent on the underlying pathogenesis of the disease. This review describes the clinical, gross, and microscopic findings of the main subtypes of chronic pancreatitis: alcoholic chronic pancreatitis, obstructive chronic pancreatitis, paraduodenal ("groove") pancreatitis, pancreatic divisum, autoimmune pancreatitis, and genetic factors associated with chronic pancreatitis. As pancreatic ductal adenocarcinoma may be confused with chronic pancreatitis, the main distinguishing features between these 2 diseases are discussed.

Exploring the metabolic syndrome: Nonalcoholic fatty pancreas disease

After the first description of fatty pancreas in 1933, the effects of pancreatic steatosis have been poorly investigated, compared with that of the liver. However, the interest of research is increasing. Fat accumulation, associated with obesity and the metabolic syndrome (MetS), has been defined as “fatty infiltration” or “nonalcoholic fatty pancreas disease” (NAFPD). The term “fatty replacement” describes a distinct phenomenon characterized by death of acinar cells and replacement by adipose tissue. Risk factors for developing NAFPD include obesity, increasing age, male sex, hypertension, dyslipidemia, alcohol and hyperferritinemia. Increasing evidence support the role of pancreatic fat in the development of type 2 diabetes mellitus, MetS, atherosclerosis, severe acute pancreatitis and even pancreatic cancer. Evidence exists that fatty pancreas could be used as the initial indicator of “ectopic fat deposition”, which is a key element of nonalcoholic fatty liver disease and/or MetS. Moreover, in patients with fatty pancreas, pancreaticoduodenectomy is associated with an increased risk of intraoperative blood loss and post-operative pancreatic fistula.

Hereditary pancreatitis of 3 Chinese children: Case report and literature review

BACKGROUND

Hereditary pancreatitis (HP) is quite rare and is distinguished by incomplete penetrance presentation as early-onset relapsing pancreatitis, usually beginning in childhood. HP is now known to be commonly relevant to mutations in the PRSS1 (gene-encoding cationic trypsinogen), SPINK1 (serine protease inhibitor, Kazal type 1), CFTR (cystic fibrosis), carboxypeptidase A1 (CPA1), and chymotrypsin C (CTRC) genes as reported in some Caucasian studies. HP has a variable spectrum of severity and may develop complications.

METHODS & RESULTS

We describe the clinical course of 3 preschool children, hospitalized with postprandial abdominal pain, whose laboratory tests showed high serum amylase. Similar episodes of abdominal pain led to readmission, and the patients recovered quickly after using symptomatic therapy. The condition of the first boy, who developed a pancreatic tail pseudocyst and splenic infarction, was especially complicated. The boy underwent 2 endoscopic retrograde cholangiopancreatographies and stenting, along with a surgical procedure that completely relieved his symptoms for 3 months. The 3 patients and their parents were given genetic testing. All of the patients carried 1 or more gene mutations inherited from their mothers, fathers, or both parents; however, none of the parents were affected.

CONCLUSION

For children with repeated pancreatitis, clinicians should consider HP in the differential diagnosis. It is reliable to perform gene sequencing on suspicious patients and their parents. Multidisciplinary and comprehensive treatment should be recommended to manage HP and its complications. Cholangiopancreatography and stenting is a relatively minimally invasive approach when compared with surgery and can be tried as an early intervention. Surgical procedures should be reserved for patients with complications.

Obesity, Intrapancreatic Fatty Infiltration, and Pancreatic Cancer

Obesity and intrapancreatic fatty infiltration are associated with increased risk of pancreatic cancer and its precursor lesions. The interplay among obesity, inflammation, and oncogenic Kras signaling promotes pancreatic tumorigenesis. Targeting the interaction between obesity-associated inflammation and Kras signaling may provide new strategies for prevention and therapy of pancreatic cancer.

Role of pancreatic fat in the outcomes of pancreatitis

The role of obesity in relation to various disease processes is being increasingly studied, with reports over the last several years increasingly mentioning its association with worse outcomes in acute disease. Obesity has also gained recognition as a risk factor for severe acute pancreatitis (SAP).The mortality in SAP may be as high as 30% and is usually attributable to multi system organ failure (MSOF) earlier in the disease, and complications of necrotizing pancreatitis later [9-11]. To date there is no specific treatment for acute pancreatitis (AP) and the management is largely expectant and supportive. Obesity in general has also been associated with poor outcomes in sepsis and other pathological states including trauma and burns. With the role of unsaturated fatty acids (UFA) as propagators in SAP having recently come to light and with the recognition of acute lipotoxicity, there is now an opportunity to explore different strategies to reduce the mortality and morbidity in SAP and potentially other disease states associated with such a pathophysiology. In this review we will discuss the role of fat and implications of the consequent acute lipotoxicity on the outcomes of acute pancreatitis in lean and obese states and during acute on chronic pancreatitis.