Exploring the enigmatic association between PNLIP variants and risk of chronic pancreatitis in a large Chinese cohort.

BACKGROUND & AIMS: Protease-sensitive PNLIP variants were recently associated with chronic pancreatitis (CP) in European populations. The pathological mechanism yet remains elusive. Herein, we performed a comprehensive genetic and functional analysis of PNLIP variants found in a large Chinese cohort, aiming to further unravel the enigmatic association of PNLIP variants with CP. METHODS: All coding and flanking intronic regions of the PNLIP gene were analyzed for rare variants by targeted next-generation sequencing in 1082 Chinese CP patients and 1196 controls. All novel missense variants were subject to analysis of secretion, lipase activity, and proteolytic degradation. One variant was further analyzed for its potential to misfold and induce endoplasmic reticulum (ER) stress. p.F300L, the most common PNLIP variant associated with CP, was used as a control. RESULTS: We identified 12 rare heterozygous PNLIP variants, with 10 being novel. The variant carrier frequency did not differ between the groups. Of them, only the variant p.A433T found in a single patient was considered pathologically relevant. p.A433T exhibited increased susceptibility to proteolytic degradation, which was much milder than p.F300L. Interestingly, both variants exhibited an increased tendency to misfold, leading to intracellular retention as insoluble aggregates, reduced secretion, and elevated ER stress. CONCLUSIONS: Our genetic and functional analysis of PNLIP variants identified in a Chinese CP cohort suggests that the p.A433T variant and the previously identified p.F300L variant are not only protease-sensitive but also may be potentially proteotoxic. Mouse studies of the PNLIP p.F300L and p.A433T variants are needed to clarify their role in CP.

Pancreas-directed AAV8-hSPINK1 gene therapy safely and effectively protects against pancreatitis in mice.

OBJECTIVE: Currently, there is no cure for chronic pancreatitis (CP). Germline loss-of-function variants in SPINK1 (encoding trypsin inhibitor) are common in patients with CP and are associated with acute attacks and progression of the disease. This preclinical study was conducted to explore the potential of adeno-associated virus type 8 (AAV8)-mediated overexpression of human SPINK1 (hSPINK1) for pancreatitis therapy in mice. DESIGN: A capsid-optimised AAV8-mediated hSPINK1 expression vector (AAV8-hSPINK1) to target the pancreas was constructed. Mice were treated with AAV8-hSPINK1 by intraperitoneal injection. Pancreatic transduction efficiency and safety of AAV8-hSPINK1 were dynamically evaluated in infected mice. The effectiveness of AAV8-hSPINK1 on pancreatitis prevention and treatment was studied in three mouse models (caerulein-induced pancreatitis, pancreatic duct ligation and Spink1 c.194+2T>C mouse models). RESULTS: The constructed AAV8-hSPINK1 vector specifically and safely targeted the pancreas, had low organ tropism for the heart, lungs, spleen, liver and kidneys and had a high transduction efficiency (the optimal expression dose was 2×1011 vg/animal). The expression and efficacy of hSPINK1 peaked at 4 weeks after injection and remained at significant level for up to at least 8 weeks. In all three mouse models, a single dose of AAV8-hSPINK1 before disease onset significantly alleviated the severity of pancreatitis, reduced the progression of fibrosis, decreased the levels of apoptosis and autophagy in the pancreas and accelerated the pancreatitis recovery process. CONCLUSION: One-time injection of AAV8-hSPINK1 safely targets the pancreas with high transduction efficiency and effectively ameliorates pancreatitis phenotypes in mice. This approach is promising for the prevention and treatment of CP.

Genetic Factors Associated With Adverse Pregnancy Outcomes in Chronic Pancreatitis.

INTRODUCTION: The effects of genetic factors on pregnancy outcomes in chronic pancreatitis (CP) patients remain unclear. We evaluated the impacts of clinical features and mutations in main CP-susceptibility genes ( SPINK1 , PRSS1 , CTRC , and CFTR ) on pregnancy outcomes in Chinese CP patients. METHODS: This was a prospective cohort study with 14-year follow-up. The sample comprised female CP patients with documented pregnancy and known genetic backgrounds. Adverse pregnancy outcomes were compared between patients with and without gene mutations. Univariate and multivariate analyses were performed to determine the impact factors for adverse pregnancy outcomes. RESULTS: Totally, 160 female CP patients with a pregnancy history were enrolled; 59.4% of patients carried pathogenic mutations in CP-susceptibility genes. Adverse pregnancy outcomes occurred in 38 patients (23.8%); the prevalence of adverse outcomes was significantly higher in those harboring gene mutations than those without (30.5% vs 13.8%, P = 0.015). Notably, the rates of preterm delivery (12.6% vs 3.1%, P = 0.036) and abortion (17.9% vs 4.6%, P = 0.013) were remarkably higher in patients with gene mutations (especially SPINK1 mutations) than those without. In multivariate analyses, both CP-susceptibility gene mutations (odds ratio, 2.52; P = 0.033) and SPINK1 mutations (odds ratio, 2.60; P = 0.037) significantly increased the risk of adverse pregnancy outcomes. Acute pain attack during pregnancy was another risk factor for adverse pregnancy outcomes. DISCUSSION: Pathogenic mutations in CP-susceptibility genes, especially SPINK1 , were independently related to adverse pregnancy outcomes in CP patients. Significant attention should be paid to pregnant females harboring CP-susceptibility gene mutations (ClinicalTrials.gov: NCT06055595).