High-resolution diffusion tensor imaging of the fornix predicts memory function in multiple sclerosis.

Background: Cognitive dysfunction is a known symptom of multiple sclerosis (MS), with memory recognized as a frequently impacted domain. Here, we used high-resolution MRI at 7 tesla to build on cross-sectional work by evaluating the longitudinal relationship of diffusion tensor imaging (DTI) measures of the fornix to episodic memory performance. Methods: A sample of 80 people with multiple sclerosis (mean age 51.9 ± 8.1 years; 24% male) underwent baseline clinical evaluation, neuropsychological assessment, and MRI. Sixty-four participants had follow-up neuropsychological testing after 1-2 years. Linear regression was used to assess the relationship of baseline imaging measures to follow-up episodic memory performance, measured using the Selective Reminding Test and Brief Visuospatial Memory Test. A reduced prediction model included cognitive function at baseline, age, sex, and disease course. Results: Radial (ß = -0.222, p < 0.026; likelihood ratio test (LRT) p < 0.018), axial (ß = -0.270, p < 0.005; LRT p < 0.003), and mean (ß = -0.242, p < 0.0139; LRT p < 0.009) diffusivity of the fornix significantly added to the model, with follow-up analysis indicating that a longer prediction interval may increase accuracy. Conclusion: These results suggest that fornix DTI has predictive value specific to memory function in MS and warrants additional investigation in the drive to develop predictors of disease progression.

Multi-shell diffusion MRI of the fornix as a biomarker for cognition in Alzheimer's disease.

BACKGROUND AND PURPOSE: A substantial fraction of those who had Alzheimer's Disease (AD) pathology on autopsy did not have dementia in life. While biomarkers for AD pathology are well-developed, biomarkers specific to cognitive domains affected by early AD are lagging. Diffusion MRI (dMRI) of the fornix is a candidate biomarker for early AD-related cognitive changes but is susceptible to bias due to partial volume averaging (PVA) with cerebrospinal fluid. The purpose of this work is to leverage multi-shell dMRI to correct for PVA and to evaluate PVA-corrected dMRI measures in fornix as a biomarker for cognition in AD. METHODS: Thirty-three participants in the Cleveland Alzheimer's Disease Research Center (CADRC) (19 with normal cognition (NC), 10 with mild cognitive impairment (MCI), 4 with dementia due to AD) were enrolled in this study. Multi-shell dMRI was acquired, and voxelwise fits were performed with two models: 1) diffusion tensor imaging (DTI) that was corrected for PVA and 2) neurite orientation dispersion and density imaging (NODDI). Values of tissue integrity in fornix were correlated with neuropsychological scores taken from the Uniform Data Set (UDS), including the UDS Global Composite 5 score (UDSGC5). RESULTS: Statistically significant correlations were found between the UDSGC5 and PVA-corrected measure of mean diffusivity (MDc, r = -0.35, p < 0.05) from DTI and the intracelluar volume fraction (ficvf, r = 0.37, p < 0.04) from NODDI. A sensitivity analysis showed that the relationship to MDc was driven by episodic memory, which is often affected early in AD, and language. CONCLUSION: This cross-sectional study suggests that multi-shell dMRI of the fornix that has been corrected for PVA is a potential biomarker for early cognitive domain changes in AD. A longitudinal study will be necessary to determine if the imaging measure can predict cognitive decline.

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.

Pancreatic Enzyme Use Reduces Pancreatitis Frequency in Children With Acute Recurrent or Chronic Pancreatitis: A Report From INSPPIRE.

INTRODUCTION: Among children who suffer from acute recurrent pancreatitis (ARP) or chronic pancreatitis (CP), acute pancreatitis (AP) episodes are painful, often require hospitalization, and contribute to disease complications and progression. Despite this recognition, there are currently no interventions to prevent AP episodes. In this retrospective cohort study, we assessed the impact of pancreatic enzyme therapy (PERT) use on clinical outcomes among children with pancreatic-sufficient ARP or CP. METHODS: Children with pancreatic-sufficient ARP or CP in the INSPPIRE-2 cohort were included. Clinical outcomes were compared for those receiving vs not receiving PERT, as well as frequency of AP before and after PERT. Logistic regression was used to study the association between development of AP episodes after starting PERT and response predictors. RESULTS: Among 356 pancreatic-sufficient participants, 270 (76%) had ARP, and 60 (17%) received PERT. Among those on PERT, 42% did not have a subsequent AP episode, during a mean 2.1 years of follow-up. Children with a SPINK1 mutation ( P = 0.005) and those with ARP (compared with CP, P = 0.008) were less likely to have an AP episode after starting PERT. After initiation of PERT, the mean AP annual incidence rate decreased from 3.14 down to 0.71 ( P < 0.001). DISCUSSION: In a retrospective analysis, use of PERT was associated with a reduction in the incidence rate of AP among children with pancreatic-sufficient ARP or CP. These results support the need for a clinical trial to evaluate the efficacy of PERT to improve clinical outcomes among children with ARP or CP.

Common single-base insertions in the VNTR of the carboxyl ester lipase (CEL) gene are benign and also likely to arise somatically in the exocrine pancreas.

The CEL gene encodes carboxyl ester lipase, a pancreatic digestive enzyme. CEL is extremely polymorphic due to a variable number tandem repeat (VNTR) located in the last exon. Single-base deletions within this VNTR cause the inherited disorder MODY8, whereas little is known about VNTR single-base insertions in pancreatic disease. We therefore mapped CEL insertion variants (CEL-INS) in 200 Norwegian patients with pancreatic neoplastic disorders. Twenty-eight samples (14.0%) carried CEL-INS alleles. Most common were insertions in repeat 9 (9.5%), which always associated with a VNTR length of 13 repeats. The combined INS allele frequency (0.078) was similar to that observed in a control material of 416 subjects (0.075). We performed functional testing in HEK293T cells of a set of CEL-INS variants, in which the insertion site varied from the first to the 12th VNTR repeat. Lipase activity showed little difference among the variants. However, CEL-INS variants with insertions occurring in the most proximal repeats led to protein aggregation and endoplasmic reticulum stress, which upregulated the unfolded protein response. Moreover, by using a CEL-INS-specific antibody, we observed patchy signals in pancreatic tissue from humans without any CEL-INS variant in the germline. Similar pancreatic staining was seen in knock-in mice expressing the most common human CEL VNTR with 16 repeats. CEL-INS proteins may therefore be constantly produced from somatic events in the normal pancreatic parenchyma. This observation along with the high population frequency of CEL-INS alleles strongly suggests that these variants are benign, with a possible exception for insertions in VNTR repeats 1-4.

Facilitating diffusion tensor imaging of the brain during continuous gross head motion with first and second order motion compensating diffusion gradients.

PURPOSE: To demonstrate the feasibility of motion compensating diffusion gradient schemes in the acquisition of quality diffusion tensor images (DTI) of the brain during continuous gross head motion. METHODS: Five healthy subjects were scanned using a clinical 3 T MRI with and without continuous head motion. For one volunteer, DTI data was acquired using standard (M0) diffusion-weighted (DW) gradients, and first (M1) and second (M2) order gradient schemes that were previously developed for use in cardiac DTI. In four additional volunteers, DTI data was acquired with M0 and M2 gradients. DTI parameters were calculated and compared with established retrospective motion corrections. RESULTS: In the absence of motion, DTI parameters calculated from M0, M1, and M2 data were consistent. In the presence of motion, up to 44% of DW images acquired with M0 gradients were corrupted by signal dropout, compared to 0% of the M2 images. In voxelwise comparisons, DTI parameters calculated using motion-M0 data were elevated compared to reference data. Retrospective corrections for extreme motion applied to motion-M0 data did not improve consistency with reference data in cases where motion corrupted >15% of DW images. In contrast, DTI parameters calculated with motion-M2 data were consistent with reference data. CONCLUSION: This proof-of-principle study demonstrates that motion compensating diffusion gradients can mitigate artifacts because of continuous motion in DTI of the brain and offers promise for improved DTI accessibility. Further study will be necessary to determine the robustness of the approach in patient populations with high susceptibility to head motion.

Characterization of novel PNLIP variants in congenital pancreatic lipase deficiency.

BACKGROUND/OBJECTIVES: Studies of a rare homozygous missense mutation identified in two brothers diagnosed with congenital pancreatic lipase deficiency (CPLD) provided the first definitive evidence linking CPLD with missense mutations in the gene of PNLIP. Herein, we investigated the molecular basis for the loss-of-function in the three novel PNLIP variants (c.305G > A, p.(W102∗); c.562C > T, p.(R188C); and c.1257G > A, p.(W419∗)) associated with CPLD. METHODS: We characterized three novel PNLIP variants in transfected cells by assessing their secretion, intracellular distribution, and markers of endoplasmic reticulum (ER) stress. RESULTS: All three variants had secretion defects. Notably, the p.R188C and p.W419∗ variants induced misfolding of PNLIP and accumulated as detergent-insoluble aggregates resulting in elevated BiP at both protein and mRNA levels indicating increased ER stress. CONCLUSIONS: All three novel PNLIP variants cause a loss-of-function through impaired secretion. Additionally, the p.R188C and p.W419∗ variants may induce proteotoxicity through misfolding and potentially increase the risk for pancreatic acinar cell injury.

Magnetic resonance fingerprinting in multiple sclerosis.

BACKGROUND: In this cross sectional study, we used MRF to investigate tissue properties of normal-appearing white matter, gray matter, and lesions in relapsing remitting MS (n = 21), secondary progressive MS (n = 16) and healthy controls (n = 9). A FISP-based MRF sequence was used for acquisition, imaging time 5 min 15 s. MRF T1 and T2 relaxation times were measured from lesional tissue, normal-appearing frontal white matter, corpus callous, thalamus, and caudate. Differences between healthy controls and MS were examined using ANCOVA adjusted for age and sex. Spearman rank correlations were assessed between T1 and T2 relaxation times and clinical measures. OBJECTIVES: To examine brain T1 and T2 values using magnetic resonance fingerprinting (MRF) in healthy controls and MS. METHODS: The subjects included 21 relapsing-remitting (RR) MS, 16 secondary progressive (SP) MS, and 9 age- and sex-matched HC without manifest neurological disease participating in a longitudinal MRI study. A 3T/ FISP-based MRF sequence was acquired. Regions of interest were drawn for lesions and normal appearing white matter. ANCOVA adjusted for age and sex were used to compare the groups with significance set at 0.05. RESULTS: A step-wise increase in T1 and T2 relaxation times was found between healthy controls, relapsing remitting MS, and secondary progressive MS. Significant differences were found in T1 and T2 between MS and healthy controls in the frontal normal-appearing white matter, corpus callosum, and thalamus (p < 0.04 for all). Significant differences in T1 and T2 between RR and SPMS were found in the frontal normal-appearing white matter and T2 lesions (p < 0.02 for all). T1 relaxation from the frontal normal-appearing white matter correlated with the Expanded Disability Status Scale [ρ = 0.62, p < 0.001], timed 25 foot walk (ρ = 0.45, p = 0.01), 9 hole peg test (ρ = 0.62, p < 0.001), and paced auditory serial addition test (ρ = -0.4, p = 0.01). CONCLUSION: These results suggest that MRF may be a clinically feasible quantitative approach for characterizing tissue damage in MS.

Bone health in children with recurrent and chronic pancreatitis: A multi-center cross sectional analysis.

BACKGROUND/OBJECTIVES: Bone health of children with acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP) is not well studied. METHODS: This retrospective study was performed at three sites and included data from INSPPIRE-2. RESULTS: Of the 87 children in the study: 46 had ARP (53%), 41 had CP (47%). Mean age was 13.6 ± 3.9 years at last DXA scan. The prevalence of low height-for-age (Z-score < -2) (13%, 10/78) and low bone mineral density (BMD) adjusted for height (Z-score < -2) (6.4%, 5/78) were higher than a healthy reference sample (2.5%, p < 0.0001 and p = 0.03, respectively). CONCLUSION: Children with ARP or CP have lower height and BMD than healthy peers. Attention to deficits in growth and bone mineral accrual in children with pancreatic disease is warranted.

Corrigendum: HBSP improves kidney ischemia-reperfusion injury and promotes repair in properdin deficient mice via enhancing phagocytosis of tubular epithelial cells.

[This corrects the article DOI: 10.3389/fimmu.2023.1183768.].

Pediatric Drug-Associated Pancreatitis Reveals Concomitant Risk Factors and Poor Reliability of Causality Scoring: Report From INSPPIRE.

OBJECTIVES: Drug-associated acute pancreatitis (DAP) studies typically focus on single acute pancreatitis (AP) cases. We aimed to analyze the (1) characteristics, (2) co-risk factors, and (3) reliability of the Naranjo scoring system for DAP using INSPPIRE-2 (the INternational Study group of Pediatric Pancreatitis: In search for a cuRE-2) cohort study of acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP) in children. METHODS: Data were obtained from ARP group with ≥1 episode of DAP and CP group with medication exposure ± DAP. Physicians could report multiple risk factors. Pancreatitis associated with Medication (Med) (ARP+CP) was compared to Non-Medication cases, and ARP-Med vs CP-Med groups. Naranjo score was calculated for each DAP episode. RESULTS: Of 726 children, 392 had ARP and 334 had CP; 51 children (39 ARP and 12 CP) had ≥1 AP associated with a medication; 61% had ≥1 AP without concurrent medication exposure. The Med group had other risk factors present (where tested): 10 of 35 (28.6%) genetic, 1 of 48 (2.1%) autoimmune pancreatitis, 13 of 51 (25.5%) immune-mediated conditions, 11 of 50 (22.0%) obstructive/anatomic, and 28 of 51 (54.9%) systemic risk factors. In Med group, 24 of 51 (47%) had involvement of >1 medication, simultaneously or over different AP episodes. There were 20 ARP and 4 CP cases in "probable" category and 19 ARP and 7 CP in "possible" category by Naranjo scores. CONCLUSIONS: Medications were involved in 51 of 726 (7%) of ARP or CP patients in INSPPIRE-2 cohort; other pancreatitis risk factors were present in most, suggesting a potential additive role of different risks. The Naranjo scoring system failed to identify any cases as "definitive," raising questions about its reliability for DAP.

HBSP improves kidney ischemia-reperfusion injury and promotes repair in properdin deficient mice via enhancing phagocytosis of tubular epithelial cells.

Phagocytosis plays vital roles in injury and repair, while its regulation by properdin and innate repair receptor, a heterodimer receptor of erythropoietin receptor (EPOR)/ß common receptor (ßcR), in renal ischaemia-reperfusion (IR) remains unclear. Properdin, a pattern recognition molecule, facilitates phagocytosis by opsonizing damaged cells. Our previous study showed that the phagocytic function of tubular epithelial cells isolated from properdin knockout (PKO) mouse kidneys was compromised, with upregulated EPOR in IR kidneys that was further raised by PKO at repair phase. Here, helix B surface peptide (HBSP), derived from EPO only recognizing EPOR/ßcR, ameliorated IR-induced functional and structural damage in both PKO and wild-type (WT) mice. In particular, HBSP treatment led to less cell apoptosis and F4/80+ macrophage infiltration in the interstitium of PKO IR kidneys compared to the WT control. In addition, the expression of EPOR/ßcR was increased by IR in WT kidneys, and furthered increased in IR PKO kidneys, but greatly reduced by HBSP in the IR kidneys of PKO mice. HBSP also increased PCNA expression in IR kidneys of both genotypes. Moreover, iridium-labelled HBSP (HBSP-Ir) was localized mainly in the tubular epithelia after 17-h renal IR in WT mice. HBSP-Ir also anchored to mouse kidney epithelial (TCMK-1) cells treated by H2O2. Both EPOR and EPOR/ßcR were significantly increased by H2O2 treatment, while further increased EPOR was showed in cells transfected with small interfering RNA (siRNA) targeting properdin, but a lower level of EPOR was seen in EPOR siRNA and HBSP-treated cells. The number of early apoptotic cells was increased by EPOR siRNA in H2O2-treated TCMK-1, but markedly reversed by HBSP. The phagocytic function of TCMK-1 cells assessed by uptake fluorescence-labelled E.coli was enhanced by HBSP dose-dependently. Our data demonstrate for the first time that HBSP improves the phagocytic function of tubular epithelial cells and kidney repair post IR injury, via upregulated EPOR/ßcR triggered by both IR and properdin deficiency.

Stimulation of the Premotor Cortex Enhances Interhemispheric Functional Connectivity in Association with Upper Limb Motor Recovery in Moderate-to-Severe Chronic Stroke.

Background: Transcranial direct current stimulation (tDCS) targeting the primary motor cortex is modestly effective for promoting upper-limb motor function following stroke. The premotor cortex (PMC) represents an alternative target based on its higher likelihood of survival and dense motor-network connections. Objective: The objective of this study was to determine whether ipsilesional PMC tDCS affects motor network functional connectivity (FC) in association with reduction in motor impairment, and to determine whether this relationship is influenced by baseline motor severity. Methods: Participants with chronic stroke were randomly assigned to receive active-PMC or sham-tDCS with rehabilitation for 5 weeks. Resting-state functional magnetic resonance imaging was acquired to characterize change in FC across motor-cortical regions. Results: Our results indicated that moderate-to-severe participants who received active-tDCS had greater increases in PMC-to-PMC interhemispheric FC compared to those who received sham; this increase was correlated with reduction in proximal motor impairment. There was also an increase in intrahemispheric dorsal premotor cortex-primary motor cortex FC across participants regardless of severity or tDCS group assignment; this increase was correlated with a reduction in proximal motor impairment in only the mild participants. Conclusions: Our findings have significance for developing targeted brain stimulation approaches. While participants with milder impairments may inherently recruit viable substrates within the ipsilesional hemisphere, stimulation of PMC may enhance interhemispheric FC in association with recovery in more impaired participants. Trial Registration: ClinicalTrials.gov Identifier: NCT01539096; Registration date: February 21, 2012.

Preclinical mouse model of a misfolded PNLIP variant develops chronic pancreatitis.

OBJECTIVE: Increasing evidence implicates mutation-induced protein misfolding and endoplasm reticulum (ER) stress in the pathophysiology of chronic pancreatitis (CP). The paucity of animal models harbouring genetic risk variants has hampered our understanding of how misfolded proteins trigger CP. We previously showed that pancreatic triglyceride lipase (PNLIP) p.T221M, a variant associated with steatorrhoea and possibly CP in humans, misfolds and elicits ER stress in vitro suggesting proteotoxicity as a potential disease mechanism. Our objective was to create a mouse model to determine if PNLIP p.T221M causes CP and to define the mechanism. DESIGN: We created a mouse model of Pnlip p.T221M and characterised the structural and biochemical changes in the pancreas aged 1-12 months. We used multiple methods including histochemistry, immunostaining, transmission electron microscopy, biochemical assays, immunoblotting and qPCR. RESULTS: We demonstrated the hallmarks of human CP in Pnlip p.T221M homozygous mice including progressive pancreatic atrophy, acinar cell loss, fibrosis, fatty change, immune cell infiltration and reduced exocrine function. Heterozygotes also developed CP although at a slower rate. Immunoblot showed that pancreatic PNLIP T221M misfolded as insoluble aggregates. The level of aggregates in homozygotes declined with age and was much lower in heterozygotes at all ages. The Pnlip p.T221M pancreas had increased ER stress evidenced by dilated ER, increased Hspa5 (BiP) mRNA abundance and a maladaptive unfolded protein response leading to upregulation of Ddit3 (CHOP), nuclear factor-κB and cell death. CONCLUSION: Expression of PNLIP p.T221M in a preclinical mouse model results in CP caused by ER stress and proteotoxicity of misfolded mutant PNLIP.

Gadolinium-based contrast agent exposures and physical and cognitive disability in multiple sclerosis.

BACKGROUND AND PURPOSE: The clinical correlation of gadolinium-based contrast agents (GBCAs) has not been well studied in multiple sclerosis (MS). We investigated the extent to which the number of GBCA administrations relates to self-reported disability and performance measures. METHODS: A cohort of MS patients was analyzed in this retrospective observational study. The main outcome was the association between the cumulative number of GBCA exposures (linear or macrocyclic GBCA), Patient-Determined Disease Steps (PDDS), and measures of physical and cognitive performance (walking speed test, manual dexterity test [MDT], and processing speed test [PST]). The analysis was performed first cross-sectionally and then longitudinally. RESULTS: The cross-sectional data included 1059 MS patients with a mean age of 44.0 years (standard deviation = 11.2). While the contrast ratio in globus pallidus weakly correlated with PDDS, MDT, and PST in a univariate correlational analysis (coefficients, 95% confidence interval [CI] = 0.11 [0.04, 0.18], 0.15 [0.08, 0.21], and -0.16 [-0.10, -0.23], respectively), the associations disappeared after covariate adjustment. A significant association was found between number of linear GBCA administrations and PDDS (coefficient [CI] = -0.131 [-0.196, -0.067]), and MDT associated with macrocyclic GBCA administrations (-0.385 [-0.616, -0.154]), but their signs indicated better outcomes in patients with greater GBCA exposures. The longitudinal data showed no significant detrimental effect of macrocyclic GBCA exposures. CONCLUSION: No detrimental effects were observed between GBCA exposure and self-reported disability and standardized objective measures of physical and cognitive performance. While several weak associations were found, they indicated benefit on these measures.

AGA-PancreasFest Joint Symposium on Exocrine Pancreatic Insufficiency.

Exocrine pancreatic insufficiency (EPI) is a clinically defined syndrome based on the physician's assessment of a patient's maldigestion. However, current clinical definitions are inadequate in determining (1) the threshold of reduced pancreatic digestive enzyme secretion that determines "pancreatic insufficiency" in an individual patient; (2) the role of pancreatic function tests; (3) effects of differing metabolic needs, nutrition intake, and intestinal function/adaptation (4) when pancreatic enzyme replacement therapy is needed; and (5) how to monitor and titrate multiple therapies. Experts and key opinion leaders were invited to PancreasFest 2021 to discuss and help clarify mechanistic issues critical to defining EPI and to address misconceptions and barriers limiting advancements in patient care. Clinically EPI is defined as inadequate delivery of pancreatic digestive enzymes to meals to meet nutritional needs and is reversed with appropriate treatment. A new mechanistic definition of EPI was proposed that includes the disorders essence and character: (1) EPI is a disorder caused by failure of the pancreas to deliver a minimum/threshold level of specific pancreatic digestive enzymes to the intestine in concert with ingested nutrients, followed by enzymatic digestion of a series of individual snacks and meals over time to meet nutritional and metabolic needs, given (a) the specific macronutritional and micronutritional needs; (b) nutrient intake; (c) exocrine pancreatic function; and (d) intestinal anatomy, function, diseases, and adaptative capacity. (2) EPI is characterized by variable deficiencies in micronutrients and macronutrients, especially essential fats and fat-soluble vitamins, by gastrointestinal symptoms of nutrient maldigestion and by improvement or correction of nutritional state with lifestyle changes, disease treatment, optimized diet, dietary supplements, and/or administration of adequate pancreatic enzyme replacement therapy. EPI is complex and individualized and multidisciplinary approaches are needed to optimize therapy. Better pancreas function tests and biomarkers are needed to diagnose EPI and guide treatment.

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.

Analysis of INSPPIRE-2 Cohort: Risk Factors and Disease Burden in Children With Acute Recurrent or Chronic Pancreatitis.

OBJECTIVES: The objective of this study is to investigate risk factors and disease burden in pediatric acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP). METHODS: Data were obtained from INternational Study group of Pediatric Pancreatitis: In search for a cuRE-2 (INSPPIRE-2), the largest multi-center prospective cohort study in pediatric patients with ARP or CP. RESULTS: Of 689 children, 365 had ARP (53%), 324 had CP (47%). CP was more commonly associated with female sex, younger age at first acute pancreatitis (AP) attack, Asian race, family history of CP, lower BMI%, genetic and obstructive factors, PRSS1 mutations and pancreas divisum. CFTR mutations, toxic-metabolic factors, medication use, hypertriglyceridemia, Crohn disease were more common in children with ARP. Constant or frequent abdominal pain, emergency room (ER) visits, hospitalizations, medical, endoscopic or surgical therapies were significantly more common in CP, episodic pain in ARP. A total of 33.1% of children with CP had exocrine pancreatic insufficiency (EPI), 8.7% had diabetes mellitus. Compared to boys, girls were more likely to report pain impacting socialization and school, medical therapies, cholecystectomy, but no increased opioid use. There was no difference in race, ethnicity, age at first AP episode, age at CP diagnosis, duration of disease, risk factors, prevalence of EPI or diabetes between boys and girls. Multivariate analysis revealed that family history of CP, constant pain, obstructive risk factors were predictors of CP. CONCLUSIONS: Children with family history of CP, constant pain, or obstructive risk factors should raise suspicion for CP.