Central role of the sentinel acute pancreatitis event (SAPE) model in understanding recurrent acute pancreatitis (RAP): Implications for precision medicine

Genetics and clinical implications of SPINK1 in the pancreatitis continuum and pancreatic cancer

Serine peptidase inhibitor, Kazal type 1 (SPINK1), a 56-amino-acid protein in its mature form, was among the first pancreatic enzymes to be extensively characterized biochemically and functionally. Synthesized primarily in pancreatic acinar cells and traditionally known as pancreatic secretory trypsin inhibitor, SPINK1 protects the pancreas by inhibiting prematurely activated trypsin. Since 2000, interest in SPINK1 has resurged following the discovery of genetic variants linked to chronic pancreatitis (CP). This review provides a historical overview of SPINK1's discovery, function, and gene structure before examining key genetic findings. We highlight three variants with well-characterized pathogenic mechanisms: c.-4141G > T, a causative enhancer variant linked to the extensively studied p.Asn34Ser (c.101A > G), which disrupts a PTF1L-binding site within an evolutionarily conserved HNF1A-PTF1L cis-regulatory module; c.194 + 2T > C, a canonical 5' splice site GT > GC variant that retains 10% of wild-type transcript production; and an Alu insertion in the 3'-untranslated region, which causes complete loss of function by forming extended double-stranded RNA structures with pre-existing Alu elements in deep intronic regions. We emphasize the integration of a full-length gene splicing assay (FLGSA) with SpliceAI's predictive capabilities, establishing SPINK1 the first disease gene for which the splicing impact of all possible coding variants was prospectively determined. Findings from both mouse models and genetic association studies support the sentinel acute pancreatitis event (SAPE) model, which explains the progression from acute pancreatitis to CP. Additionally, SPINK1 variants may contribute to an increased risk of pancreatic ductal adenocarcinoma (PDAC). Finally, we discuss the therapeutic potential of SPINK1, particularly through adeno-associated virus type 8 (AAV8)-mediated overexpression of SPINK1 as a strategy for treating and preventing pancreatitis, and highlight key areas for future research.

Heterogeneity in Pancreatitis: Recognizing Heterogeneity and Its Role in the Management of Pancreatitis Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

ABSTRACT

Both the clinical management and study of recurrent acute pancreatitis and chronic pancreatitis are complicated by significant heterogeneity in the etiology, mechanisms, symptoms, and complications of pancreatitis. The National Institutes of Diabetes and Digestive and Kidney Disease recently convened a workshop to address current knowledge and knowledge gaps in the field. Preclinical models that better replicate human disease are important for development of new therapies. Pain is often the most common and most difficult symptom to treat, as the causes are multifactorial and effective treatment may vary depending on whether pain is neuropathic or nociceptive in origin, and the placebo effect can complicate evaluation of the efficacy of medical and procedural interventions. Novel technologies like functional magnetic resonance imaging and virtual reality may offer novel means for assessing and treating pain, respectively. Clinical trial designs will need to consider best approaches to addressing the heterogeneity of chronic pancreatitis, including careful attention to designing eligibility criteria, and establishing accepted and validated core outcomes criteria for the field. The latter may be informed by consensus in pain research. Recruitment of participants into clinical trials has been challenging, often requiring multiple centers. Establishment of a clinical trials network would facilitate greater opportunities for therapeutic trials in pancreatitis.

Analysis of risk factors related to acute exacerbation in patients with chronic pancreatitis: a retrospective study of 313 cases from a single center in China

BACKGROUND

Acute on chronic pancreatitis(ACP) is a common cause of treatment in patients with chronic pancreatitis(CP). However, as far as we know, research on ACP has been few, and the quality may vary. This study intended to explore the risk factors related to acute exacerbation in patients with chronic pancreatitis.

METHODS

313 patients with CP were analyzed based on clinical data from 2014 to 2023 and categorized into ACP and non-ACP groups. Their data, assessed across eleven parameters, were used to study risk variables associated with acute exacerbation in patients with chronic pancreatitis.

RESULTS

Of the 313 eligible patients, 163(52.1%) were ACP. Age > 50 years old (P = 0.049, OR = 0.614, 95%CI: 0.378-0.998), recurrent acute pancreatitis(RAP) history (P = 0.000, OR = 3.284, 95%CI: 1.972-5.467) and steatorrhea (P = 0.013, OR = 0.189, 95%CI: 0.051-0.704) were related factors for ACP.

CONCLUSION

The history of RAP was an independent risk factor for ACP. Age and steatosis were protective of the prevalence of ACP.

Trypsin in pancreatitis: The culprit, a mediator, or epiphenomenon?

Pancreatitis is a common, life-threatening inflammatory disease of the exocrine pancreas. Its pathogenesis remains obscure, and no specific or effective treatment is available. Gallstones and alcohol excess are major etiologies of pancreatitis; in a small portion of patients the disease is hereditary. Pancreatitis is believed to be initiated by injured acinar cells (the main exocrine pancreas cell type), leading to parenchymal necrosis and local and systemic inflammation. The primary function of these cells is to produce, store, and secrete a variety of enzymes that break down all categories of nutrients. Most digestive enzymes, including all proteases, are secreted by acinar cells as inactive proforms (zymogens) and in physiological conditions are only activated when reaching the intestine. The generation of trypsin from inactive trypsinogen in the intestine plays a critical role in physiological activation of other zymogens. It was proposed that pancreatitis results from proteolytic autodigestion of the gland, mediated by premature/inappropriate trypsinogen activation within acinar cells. The intra-acinar trypsinogen activation is observed in experimental models of acute and chronic pancreatitis, and in human disease. On the basis of these observations, it has been considered the central pathogenic mechanism of pancreatitis - a concept with a century-old history. This review summarizes the data on trypsinogen activation in experimental and genetic rodent models of pancreatitis, particularly the more recent genetically engineered mouse models that mimic mutations associated with hereditary pancreatitis; analyzes the mechanisms mediating trypsinogen activation and protecting the pancreas against its' damaging effects; discusses the gaps in our knowledge, potential therapeutic approaches, and directions for future research. We conclude that trypsin is not the culprit in the disease pathogenesis but, at most, a mediator of some pancreatitis responses. Therefore, the search for effective therapies should focus on approaches to prevent or normalize other intra-acinar pathologic processes, such as defective autophagy leading to parenchymal cell death and unrelenting inflammation.

Meandering main pancreatic duct syndrome: a single-center cohort study and aggregated review

Background

Meandering main pancreatic duct (MMPD) refers to an uncommon ductal variant of the normal smooth curvilinear course of the pancreatic duct. More specifically, MMPD is characterized by a hairpin (reverse Z-type) or loop (loop-type) turn in the pancreatic head. It has been suggested as a predisposing factor for the development of pancreatitis. Studies regarding treatment are scarce.

Methods

We conducted a narrative review of the current literature regarding MMPD. Additionally, we present a cohort of 9 symptomatic patients treated endoscopically at our tertiary center.

Results

Seven retrospective cohort studies and 4 case reports were included in our review. Only 1 study focuses on the clinical significance of MMPD and describes a positive association between MMPD and the onset of pancreatitis, especially recurrent acute pancreatitis. Only 1 case reports an endoscopic treatment. In our cohort of 9 MMPD patients, 7 did indeed present with recurrent acute pancreatitis. Endotherapy provided substantial regression of symptoms in 6 patients, all of whom had signs of ductal hypertension.

Conclusions

Our review shows the scarcity of data regarding MMPD, especially concerning treatment, in the current literature. With our cohort, we not only hope to raise awareness of this often-neglected entity of recurrent acute pancreatitis, but also support the case for endotherapy for the first time in 9 symptomatic MMPD patients, especially in the presence of ductal hypertension.

Incidence of recurrent and chronic pancreatitis after acute pancreatitis: a systematic review and meta-analysis

Background

Acute pancreatitis (AP) has a high incidence, and patients can develop recurrent acute pancreatitis (RAP) and chronic pancreatitis (CP) after AP.

Objectives

We aimed to estimate the pooled incidence rates (IRs), cumulative incidences, and proportions of RAP and CP after AP.

Design

A systematic review and meta-analysis of studies reporting the proportion of RAP and CP after AP.

Data sources and methods

The systematic search was conducted in three (PubMed, EMBASE, and CENTRAL) databases on 19 December 2023. Articles reporting the proportion of RAP or CP in patients after the first and multiple episodes of AP were eligible. The random effects model was used to calculate the pooled IR with 95% confidence intervals (CIs). The I 2 value assessed heterogeneity. The risk of bias assessment was conducted with the Joanna Briggs Institute Critical Appraisal Tool.

Results

We included 119 articles in the quantitative synthesis and 29 in the IRs calculations. Our results showed that the IR of RAP in adult patients after AP was 5.26 per 100 person-years (CI: 3.99-6.94; I 2 = 93%), while in children, it was 4.64 per 100 person-years (CI: 2.73-7.87; I 2 = 88%). We also found that the IR of CP after AP was 1.4 per 100 person-years (CI: 0.9-2; I 2 = 75%), while after RAP, it increased to 4.3 per 100 person-years (CI: 3.1-6.0; I 2 = 76%). The risk of bias was moderate in the majority of the included studies.

Conclusion

Our results showed that RAP affects many patients with AP. Compared to patients with the first AP episode, RAP leads to a threefold higher IR for developing CP.

Trial registration

Our protocol was registered on PROSPERO (CRD42021283252).

CFTR function is impaired in a subset of patients with pancreatitis carrying rare CFTR variants

BACKGROUND

Many affected by pancreatitis harbor rare variants of the cystic fibrosis (CF) gene, CFTR, which encodes an epithelial chloride/bicarbonate channel. We investigated CFTR function and the effect of CFTR modulator drugs in pancreatitis patients carrying CFTR variants.

METHODS

Next-generation sequencing was performed to identify CFTR variants. Sweat tests and nasal potential difference (NPD) assays were performed to assess CFTR function in vivo. Intestinal current measurement (ICM) was performed on rectal biopsies. Patient-derived intestinal epithelial monolayers were used to evaluate chloride and bicarbonate transport and the effects of a CFTR modulator combination: elexacaftor, tezacaftor and ivacaftor (ETI).

RESULTS

Of 32 pancreatitis patients carrying CFTR variants, three had CF-causing mutations on both alleles and yielded CF-typical sweat test, NPD and ICM results. Fourteen subjects showed a more modest elevation in sweat chloride levels, including three that were provisionally diagnosed with CF. ICM indicated impaired CFTR function in nine out of 17 non-CF subjects tested. This group of nine included five carrying a wild type CFTR allele. In epithelial monolayers, a reduction in CFTR-dependent chloride transport was found in six out of 14 subjects tested, whereas bicarbonate secretion was reduced in only one individual. In epithelial monolayers of four of these six subjects, ETI improved CFTR function.

CONCLUSIONS

CFTR function is impaired in a subset of pancreatitis patients carrying CFTR variants. Mutations outside the CFTR locus may contribute to the anion transport defect. Bioassays on patient-derived intestinal tissue and organoids can be used to detect such defects and to assess the effect of CFTR modulators.

The burden of recurrence acute pancreatitis and annual event rates are underestimated because of high rates of home self-management

BACKGROUND/OBJECTIVES

The event-rate of recurrent acute pancreatitis (RAP) in patient populations is critical for powering research studies. We hypothesize that some patients manage RAP attacks at home, reducing event rate estimations based on counting emergency department (ED) visits and hospitalizations only. The aim of this study was to determine the rates of home self-management of recurrent acute pancreatitis compared to ED visits and hospitalizations.

METHODS

An anonymous 8-question survey was sent to 1825 individuals on an email list of individuals with a history of acute pancreatitis (AP) or chronic pancreatitis or interest in pancreatic diseases. Question were designed to identify subjects with RAP within the past 2 years and to subdivide patients based on having a chronic pain syndrome or not.

RESULTS

After an initial email request and one reminder a total of 194 subjects responded with 98 RAP subjects suitable for analysis. Annual AP events included an average of 1.44 hospitalizations, 1.37 ED visits, 2.46 disrupted work/school/social engagements, and 3.95 pancreatitis-like pain attacks per year. Patients with RAP average 6.8 RAP events per year with 58.4 % managed at home.

CONCLUSIONS

The burden of disease in patients with RAP is significantly underestimated, especially for patients with chronic pain. Future studies should include measures to capture RAP events managed at home and utilize methods of documenting RAP events.

Management of chronic pancreatitis

Chronic pancreatitis results from repeated episodes of pancreatic inflammation and associated fibrosis leading to the loss of functional exocrine and endocrine pancreatic function. The disease is manifested by abdominal pain, deterioration in quality of life, food maldigestion and malabsorption, diabetes, and an increased risk for pancreatic adenocarcinoma. This review summarizes the latest evidence on the diagnosis and management of chronic pancreatitis and its manifestations. In particular, this review discusses advances in understanding of the role of genetic disorders in the mechanisms of the disease and surgical options for patients refractory to medical therapy. Furthermore, clinical trials are under way to develop medical therapeutics.

Pro-inflammatory cytokines stimulate CFTR-dependent anion secretion in pancreatic ductal epithelium

BACKGROUND

Loss of CFTR-dependent anion and fluid secretion in the ducts of the exocrine pancreas is thought to contribute to the development of pancreatitis, but little is known about the impact of inflammation on ductal CFTR function. Here we used adult stem cell-derived cell cultures (organoids) obtained from porcine pancreas to evaluate the effects of pro-inflammatory cytokines on CFTR function.

METHODS

Organoids were cultured from porcine pancreas and used to prepare ductal epithelial monolayers. Monolayers were characterized by immunocytochemistry. Epithelial bicarbonate and chloride secretion, and the effect of IL-1β, IL-6, IFN-γ, and TNF-α on CFTR function was assessed by electrophysiology.

RESULTS

Immunolocalization of ductal markers, including CFTR, keratin 7, and zonula occludens 1, demonstrated that organoid-derived cells formed a highly polarized epithelium. Stimulation by secretin or VIP triggered CFTR-dependent anion secretion across epithelial monolayers, whereas purinergic receptor stimulation by UTP, elicited CFTR-independent anion secretion. Most of the anion secretory response was attributable to bicarbonate transport. The combination of IL-1β, IL-6, IFN-γ, and TNF-α markedly enhanced CFTR expression and anion secretion across ductal epithelial monolayers, whereas these cytokines had little effect when tested separately. Although TNF-α triggered apoptotic signaling, epithelial barrier function was not significantly affected by cytokine exposure.

CONCLUSIONS

Pro-inflammatory cytokines enhance CFTR-dependent anion secretion across pancreatic ductal epithelium. We propose that up-regulation of CFTR in the early stages of the inflammatory response, may serve to promote the removal of pathogenic stimuli from the ductal tree, and limit tissue injury.