Trypsinogen mutations in pancreatic disorders

Pancreatic cancer epidemiology: understanding the role of lifestyle and inherited risk factors

Pancreatic cancer is a leading cause of cancer death worldwide and its global burden has more than doubled over the past 25 years. The highest incidence regions for pancreatic cancer include North America, Europe and Australia, and although much of this increase is due to ageing worldwide populations, there are key modifiable risk factors for pancreatic cancer such as cigarette smoking, obesity, diabetes and alcohol intake. The prevalence of these risk factors is increasing in many global regions, resulting in increasing age-adjusted incidence rates for pancreatic cancer, but the relative contribution from these risk factors varies globally due to variation in the underlying prevalence and prevention strategies. Inherited genetic factors, although not directly modifiable, are an important component of pancreatic cancer risk, and include pathogenic variants in hereditary cancer genes, genes associated with hereditary pancreatitis, as well as common variants identified in genome-wide association studies. Identification of the genetic changes that underlie pancreatic cancer not only provides insight into the aetiology of this cancer but also provides an opportunity to guide early detection strategies. The goal of this Review is to provide an up-to-date overview of the established modifiable and inherited risk factors for pancreatic cancer.

Interleukin 18 as an early marker or prognostic factor in acute pancreatitis

INTRODUCTION

Acute pancreatits (AP) still reqiures better diagnostic and therapeutic options to be introduced in order to decrease its morbidity and mortality. It appears that the assessment of serum levels of interleukin 18 (IL-18) and its correlation with C-reactive protein (CRP) may provide adequate prognostic value.

AIM

To measure serum concentrations of IL-18 and inflammation markers such as CRP in patients with AP during subsequent hospital stay days and to assess the role of IL-18 as an early AP marker and prognostic factor.

MATERIAL AND METHODS

Thirty-two patients aged 47 ±16.7 years were included into the study (17 males and 15 females), in whom AP was diagnosed based on ultrasound and computer aided tomography imaging and amylase. Serum amylase, CRP, and IL-18 levels were measured on the 1(st), 2(nd), 3(rd), and 5(th) days of hospital stay. All patients were scored "B" according to Balthazar and mild AP based on Ranson criteria. The control group consisted of 30 healthy volunteers aged 50.7 ±12.4 years (15 males and 15 females).

RESULTS

The average IL-18 serum level in the control group was 86.91 ±4.94 pg/ml. Mean IL-18 study group levels were 128.4 ±7.6 pg/ml on the 1(st), 112.0 ±4.4 pg/ml on the 3(rd), and 122.8 ±6.8 pg/ml on the 5(th) day of AP, and were significantly higher than those in the control group, accordingly: p < 0.001, p < 0.005, p < 0.001. A positive correlation between IL-18 and CRP serum concentrations was observed. A slight increase in correlation was observed as the days went by.

CONCLUSIONS

We concluded that the serum IL-18 level increases in the initial phase of AP, and it may be used as an inflammatory reaction marker in patients with AP, and it is correlated with CRP, which may indicate its prognostic role in AP.

Human cationic trypsinogen but not serine peptidase inhibitor, Kazal type 1 variants increase the risk of type 1 autoimmune pancreatitis

BACKGROUND AND AIM

Autoimmune pancreatitis (AIP) is a distinct disease entity. Whether the genes involved in pancreatic acinar cell injury, cationic trypsinogen gene (protease, serine, 1 [trypsin 1] [PRSS1]) and the pancreatic secretory trypsin inhibitor gene (serine peptidase inhibitor, Kazal type 1 [SPINK1]), are associated with AIP remains to be explored.

METHODS

Genetic analyses of PRSS1 variants (exon 2 and 3) and SPINK1 variants (exon 1, 2, and 3) including the intronic areas in 118 patients with AIP and 200 control subjects were performed by direct DNA sequencing. Clinical features including imaging, histology, serology, response to steroid, and extra-pancreatic organ involvement in AIP patients with and without variants were compared.

RESULTS

A total of 19 PRSS1 variants and one SPINK1 variant were identified in 20 (16.9%) out of 118 AIP patients. They included one K92N, nine R116C, seven T137M, one C139S, and one C139F of PRSS1 and one 2(IVS3 + 2) of SPINK1. No PRSS1 or SPINK1 variant was identified in the control group. Patients with PRSS1 variants had an increased risk of AIP with odds ratio 22.37 (95% confidence interval: 2.96-168.8, P = 0.003) and higher frequency of serum IgG4 above 280 mg/dL. Using immunosuppressive agent and PRSS1 variant were predictors of less disease relapse in univariate analysis. Presence of PRSS1 variants was the only negative predictor for disease relapse in multivariate analysis.

CONCLUSIONS

We found a significantly higher frequency of PRSS1 variants in AIP patients than in geographically and ethnically matched control subjects. PRSS1 variants are associated with less disease relapse in AIP.

Genetic counseling for nonsyndromic pancreatitis

An appreciation for the background of disease, not to mention the medical management of individuals, may be significantly affected by testing for mutations and genetic variants associated with pancreatitis. Pretest and posttest counseling are essential for patients and families to benefit fully from genetic testing for a susceptibility to develop pancreatitis. The clinician, often working directly with a qualified genetic counselor, must ensure that patients and families appreciate the benefits and limitations of genetic tests, that results are interpreted accurately, and that patients understand implications of information for both their medical care and personal decisions. This article focuses on the approach to genetic counseling for pancreatitis and implications of recent advances.

A mouse model of hereditary pancreatitis generated by transgenic expression of R122H trypsinogen

BACKGROUND & AIMS

Missense mutations in human cationic trypsinogen PRSS1 are frequently detected in patients with hereditary pancreatitis, a rare genetic disease of the pancreas characterized by autodigestive necrosis, chronic inflammation, and fibrosis. To examine the link between PRSS1 mutations and the initiation and progression of hereditary pancreatitis, we have sought to generate a transgenic mouse that carries a missense mutation in the PRSS1 that is most frequently observed in patients.

METHODS

A transgenic mouse was generated in which the expression of the mouse PRSS1 mutant R122H (R122H_mPRSS1) is targeted to pancreatic acinar cells by fusion to the elastase promoter. The expression of the mutant trypsinogen was assessed by immunohistochemical staining and real-time reverse transcription polymerase chain reaction analysis. The relationship between transgene expression and inflammation was analyzed by morphologic assessment of H&E-stained tissue sections, responsiveness to cerulein-induced pancreatitis, and immunohistochemical identification of cellular and biochemical components of the inflammatory response.

RESULTS

Pancreata from transgenic mice display early-onset acinar cell injury and inflammatory cell infiltration. With progressing age, the transgenic mice develop pancreatic fibrosis and display acinar cell dedifferentiation. Moreover, the expression of R122H_mPRSS1 transgene is associated with enhanced response to cerulein-induced pancreatitis. Finally, cell-specific activation of the inflammation-associated signaling pathways, c-jun-N-terminal kinase and extracellular signal-regulated kinase, was observed in response to expression of R122H_mPRSS1.

CONCLUSIONS

These results underscore the importance of PRSS1 mutations as pathogenic mediators of hereditary pancreatitis and indicate that persistent pancreatic injury might be causally linked to chronic pancreatitis.