Salivary gland function, development, and regeneration.

Salivary glands produce and secrete saliva, which is essential for maintaining oral health and overall health. Understanding both the unique structure and physiological function of salivary glands, as well as how they are affected by disease and injury, will direct the development of therapy to repair and regenerate them. Significant recent advances, particularly in the OMICS field, increase our understanding of how salivary glands develop at the cellular, molecular, and genetic levels: the signaling pathways involved, the dynamics of progenitor cell lineages in development, homeostasis, and regeneration, and the role of the extracellular matrix microenvironment. These provide a template for cell and gene therapies as well as bioengineering approaches to repair or regenerate salivary function.

The orphan nuclear receptor SHP regulates ER stress response by inhibiting XBP1s degradation.

The orphan nuclear receptor SHP (small heterodimer partner) is a well-known transcriptional corepressor of bile acid and lipid metabolism in the liver; however, its function in other tissues is poorly understood. Here, we report an unexpected role for SHP in the exocrine pancreas as a modulator of the endoplasmic reticulum (ER) stress response. SHP expression is induced in acinar cells in response to ER stress and regulates the protein stability of the spliced form of X-box-binding protein 1 (XBP1s), a key mediator of ER stress response. Loss of SHP reduces XBP1s protein level and transcriptional activity, which in turn attenuates the ER stress response during the fasting-feeding cycle. Consequently, SHP-deficient mice also are more susceptible to cerulein-induced pancreatitis. Mechanistically, we show that SHP physically interacts with the transactivation domain of XBP1s, thereby inhibiting the polyubiquitination and degradation of XBP1s by the Cullin3-SPOP (speckle-type POZ protein) E3 ligase complex. Together, our data implicate SHP in governing ER homeostasis and identify a novel posttranslational regulatory mechanism for the key ER stress response effector XBP1.

Structured RhoGEF recruitment drives myosin II organization on large exocytic vesicles.

The Rho family of GTPases plays a crucial role in cellular mechanics by regulating actomyosin contractility through the parallel induction of actin and myosin assembly and function. Using exocytosis of large vesicles in the Drosophila larval salivary gland as a model, we followed the spatiotemporal regulation of Rho1, which in turn creates distinct organization patterns of actin and myosin. After vesicle fusion, low levels of activated Rho1 reach the vesicle membrane and drive actin nucleation in an uneven, spread-out pattern. Subsequently, the Rho1 activator RhoGEF2 distributes as an irregular meshwork on the vesicle membrane, activating Rho1 in a corresponding punctate pattern and driving local myosin II recruitment, resulting in vesicle constriction. Vesicle membrane buckling and subsequent crumpling occur at local sites of high myosin II concentrations. These findings indicate that distinct thresholds for activated Rho1 create a biphasic mode of actomyosin assembly, inducing anisotropic membrane crumpling during exocrine secretion.

Normal and Sjogren's syndrome models of the murine lacrimal gland studied at single-cell resolution.

The lacrimal gland is of central interest in ophthalmology both as the source of the aqueous component of tear fluid and as the site of autoimmune pathology in the context of Sjogren's syndrome (SjS). To provide a foundational description of mouse lacrimal gland cell types and their patterns of gene expression, we have analyzed single-cell transcriptomes from wild-type (Balb/c) mice and from two genetically based SjS models, MRL/lpr and NOD (nonobese diabetic).H2b, and defined the localization of multiple cell-type-specific protein and mRNA markers. This analysis has uncovered a previously undescribed cell type, Car6+ cells, which are located at the junction of the acini and the connecting ducts. More than a dozen secreted polypeptides that are likely to be components of tear fluid are expressed by acinar cells and show pronounced sex differences in expression. Additional examples of gene expression heterogeneity within a single cell type were identified, including a gradient of Claudin4 along the length of the ductal system and cell-to-cell heterogeneity in transcription factor expression within acinar and myoepithelial cells. The patterns of expression of channels, transporters, and pumps in acinar, Car6+, and ductal cells make strong predictions regarding the mechanisms of water and electrolyte secretion. In MRL/lpr and NOD.H2b lacrimal glands, distinctive changes in parenchymal gene expression and in immune cell subsets reveal widespread interferon responses, a T cell-dominated infiltrate in the MRL/lpr model, and a mixed B cell and T cell infiltrate in the NOD.H2b model.

A Single-Cell Atlas of the Murine Pancreatic Ductal Tree Identifies Novel Cell Populations With Potential Implications in Pancreas Regeneration and Exocrine Pathogenesis.

BACKGROUND & AIMS: Pancreatic ducts form an intricate network of tubules that secrete bicarbonate and drive acinar secretions into the duodenum. This network is formed by centroacinar cells; terminal, intercalated, intracalated ducts; and the main pancreatic duct. Ductal heterogeneity at the single-cell level has been poorly characterized; therefore, our understanding of the role of ductal cells in pancreas regeneration and exocrine pathogenesis has been hampered by the limited knowledge and unexplained diversity within the ductal network. METHODS: We used small conditional RNA sequencing to comprehensively characterize mouse ductal heterogeneity at single-cell resolution of the entire ductal epithelium from centroacinar cells to the main duct. Moreover, we used organoid cultures, injury models, and pancreatic tumor samples to interrogate the role of novel ductal populations in pancreas regeneration and exocrine pathogenesis. RESULTS: We have identified the coexistence of 15 ductal populations within the healthy pancreas and characterized their organoid formation capacity and endocrine differentiation potential. Cluster isolation and subsequent culturing let us identify ductal cell populations with high organoid formation capacity and endocrine and exocrine differentiation potential in vitro, including a Wnt-responsive population, a ciliated population, and FLRT3+ cells. Moreover, we have characterized the location of these novel ductal populations in healthy pancreas, chronic pancreatitis, and tumor samples. The expression of WNT-responsive, interferon-responsive, and epithelial-to-mesenchymal transition population markers increases in chronic pancreatitis and tumor samples. CONCLUSIONS: In light of our discovery of previously unidentified ductal populations, we unmask potential roles of specific ductal populations in pancreas regeneration and exocrine pathogenesis. Thus, novel lineage-tracing models are needed to investigate ductal-specific populations in vivo.

Cancer-associated endocrine cells participate in pancreatic carcinogenesis.

BACKGROUND & AIMS: The pancreas is composed of endocrine and exocrine parts, and its interlacing structure indicates potential interaction between endocrine and exocrine cells. Although the tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) has been well characterized, the role of pancreatic endocrine cells during carcinogenesis is relatively understudied. METHODS: We depicted the changes of endocrine cells in PDAC by single-cell transcriptome sequencing, spatial transcriptome sequencing and multiplex immunohistochemistry. After that, the interaction between pancreatic carcinogenesis and endocrine changes was explored in orthotopic transplantation mice, KC mice and KPC mice. Finally, we proved the mechanism of the interaction between endocrine and exocrine parts of the pancreas through islet isolation, co-culture in vitro and co-injection in vivo. RESULTS: We found that pancreatic endocrine cells displayed significantly different transcriptomic characteristics and increased interaction with exocrine part in PDAC. Specifically, among all the changes, pancreatic polypeptide positive (PPY+) cells showed a sharp increment accompanied with the progression of the cancer lesion, which might be derived from the transdifferentiation of α and ß cells. Interestingly, it was proved that PDAC cells were able to induce the transdifferentiation of pancreatic α cells and ß cells into GCG+PPY+ and INS+PPY+ double-positive cells, which further promoted carcinogenesis and development of PDAC in a paracrine-dependent manner and formed a reciprocal interaction. CONCLUSIONS: Our study systematically maps the alteration of pancreatic endocrine cells in PDAC and elucidates the potential endocrine-exocrine interaction mechanisms during PDAC carcinogenesis. Meanwhile, we first time define and characterize cancer-associated endocrine cells (CAEs), thereby further broadening the composition of PDAC microenvironment.

Exocrine gland structure-function relationships.

Fluid secretion by exocrine glandular organs is essential to the survival of mammals. Each glandular unit within the body is uniquely organized to carry out its own specific functions, with failure to establish these specialized structures resulting in impaired organ function. Here, we review glandular organs in terms of shared and divergent architecture. We first describe the structural organization of the diverse glandular secretory units (the end-pieces) and their fluid transporting systems (the ducts) within the mammalian system, focusing on how tissue architecture corresponds to functional output. We then highlight how defects in development of end-piece and ductal architecture impacts secretory function. Finally, we discuss how knowledge of exocrine gland structure-function relationships can be applied to the development of new diagnostics, regenerative approaches and tissue regeneration.

The venom and telopodal defence systems of the centipede Lithobius forficatus are functionally convergent serial homologues.

BACKGROUND: Evolution of novelty is a central theme in evolutionary biology, yet studying the origins of traits with an apparently discontinuous origin remains a major challenge. Venom systems are a well-suited model for the study of this phenomenon because they capture several aspects of novelty across multiple levels of biological complexity. However, while there is some knowledge on the evolution of individual toxins, not much is known about the evolution of venom systems as a whole. One way of shedding light on the evolution of new traits is to investigate less specialised serial homologues, i.e. repeated traits in an organism that share a developmental origin. This approach can be particularly informative in animals with repetitive body segments, such as centipedes. RESULTS: Here, we investigate morphological and biochemical aspects of the defensive telopodal glandular organs borne on the posterior legs of venomous stone centipedes (Lithobiomorpha), using a multimethod approach, including behavioural observations, comparative morphology, proteomics, comparative transcriptomics and molecular phylogenetics. We show that the anterior venom system and posterior telopodal defence system are functionally convergent serial homologues, where one (telopodal defence) represents a model for the putative early evolutionary state of the other (venom). Venom glands and telopodal glandular organs appear to have evolved from the same type of epidermal gland (four-cell recto-canal type) and while the telopodal defensive secretion shares a great degree of compositional overlap with centipede venoms in general, these similarities arose predominantly through convergent recruitment of distantly related toxin-like components. Both systems are composed of elements predisposed to functional innovation across levels of biological complexity that range from proteins to glands, demonstrating clear parallels between molecular and morphological traits in the properties that facilitate the evolution of novelty. CONCLUSIONS: The evolution of the lithobiomorph telopodal defence system provides indirect empirical support for the plausibility of the hypothesised evolutionary origin of the centipede venom system, which occurred through functional innovation and gradual specialisation of existing epidermal glands. Our results thus exemplify how continuous transformation and functional innovation can drive the apparent discontinuous emergence of novelties on higher levels of biological complexity.

Tmed10 deficiency results in impaired exocrine pancreatic differentiation in zebrafish larvae.

Transmembrane p24 trafficking protein 10 (TMED10) is a conserved vesicle trafficking protein. It is dysregulated in Alzheimer disease and plays a pivotal role in the pathogenesis of Alzheimer disease. In addition to the brain, TMED10 is highly expressed in the exocrine pancreas; however, its biological functions and underlying mechanisms remain largely unknown. We studied reduced Tmed10 in zebrafish embryos by morpholino oligonucleotide knockdown and CRISPR-Cas9 mutagenesis. Tmed10-deficient embryos showed extensive loss of acinar mass and impaired acinar differentiation. TMED10 has been reported to have an inhibitory effect on γ-secretase. As one of the substrates of γ-secretase, membrane-bound ß-catenin was significantly reduced in Tmed10-deficient embryos. Increased γ-secretase activity in wild-type embryos resulted in a phenotype similar to that of tmed10 mutants. And the mutant phenotype could be rescued by treatment with the γ-secretase inhibitor, N-[N-(3, 5-difluorophenacetyl)-l-alanyl]-s-phenylglycinet-butyl ester (DAPT). In addition, the reduced membrane-bound ß-catenin was accompanied with up-regulated ß-catenin target genes in Tmed10-deficient embryos. Overexpression of ß-catenin signaling inhibitor Dickkopf-1 (DKK-1) could rescue the exocrine pancreas defects. Taken together, our study reveals that Tmed10 regulates exocrine pancreatic differentiation through γ-secretase. Reduced membrane-bound ß-catenin, accompanied with hyperactivation of ß-catenin signaling, is an important cause of exocrine pancreas defects in Tmed10-deficient embryos. Our study reaffirms the importance of appropriate ß-catenin signaling in exocrine pancreas development. These findings may provide a theoretical basis for the development of treatment strategies for TMED10-related diseases.

Pacing intracellular Ca2+ signals in exocrine acinar cells.

An increase in intracellular [Ca2+ ] in exocrine acinar cells resident in the salivary glands or pancreas is a fundamental event that drives fluid secretion and exocytosis of proteins. Stimulation with secretagogues initiates Ca2+ signals with precise spatiotemporal properties thought to be important for driving physiological output. Both in vitro, in acutely isolated acini, and in vivo, in animals expressing genetically encoded indicators, individual cells appear specialized to initiate Ca2+ signals upon stimulation. Furthermore, these signals appear to spread to neighbouring cells. These properties are present in the absence of a conventional pacemaker mechanism dependent on the cyclical activation of Ca2+ -dependent or Ca2+ -conducting plasma membrane ion channels. In this article, we propose a model for 'pacing' intracellular Ca2+ signals in acinar cells based on the enhanced sensitivity of a subpopulation of individual cells and the intercellular diffusion through gap junctions of inositol 1,4,5-trisphosphate and Ca2+ to neighbouring cells.

Role of CFTR in diabetes-induced pancreatic ductal fluid and HCO3 - secretion.

Type 1 diabetes is a disease of the endocrine pancreas; however, it also affects exocrine function. Although most studies have examined the effects of diabetes on acinar cells, much less is known regarding ductal cells, despite their important protective function in the pancreas. Therefore, we investigated the effect of diabetes on ductal function. Diabetes was induced in wild-type and cystic fibrosis transmembrane conductance regulator (CFTR) knockout mice following an i.p. administration of streptozotocin. Pancreatic ductal fluid and HCO3 - secretion were determined using fluid secretion measurements and fluorescence microscopy, respectively. The expression of ion transporters was measured by real-time PCR and immunohistochemistry. Transmission electron microscopy was used for the morphological characterization of the pancreas. Serum secretin and cholecystokinin levels were measured by an enzyme-linked immunosorbent assay. Ductal fluid and HCO3 - secretion, CFTR activity, and the expression of CFTR, Na+ /H+ exchanger-1, anoctamine-1 and aquaporin-1 were significantly elevated in diabetic mice. Acute or chronic glucose treatment did not affect HCO3 - secretion, but increased alkalizing transporter activity. Inhibition of CFTR significantly reduced HCO3 - secretion in both normal and diabetic mice. Serum levels of secretin and cholecystokinin were unchanged, but the expression of secretin receptors significantly increased in diabetic mice. Diabetes increases fluid and HCO3 - secretion in pancreatic ductal cells, which is associated with the increased function of ion and water transporters, particularly CFTR. KEY POINTS: There is a lively interaction between the exocrine and endocrine pancreas not only under physiological conditions, but also under pathophysiological conditions The most common disease affecting the endocrine part is type-1 diabetes mellitus (T1DM), which is often associated with pancreatic exocrine insufficiency Compared with acinar cells, there is considerably less information regarding the effect of diabetes on pancreatic ductal epithelial cells, despite the fact that the large amount of fluid and HCO3 - produced by ductal cells is essential for maintaining normal pancreatic functions Ductal fluid and HCO3 - secretion increase in T1DM, in which increased cystic fibrosis transmembrane conductance regulator activation plays a central role. We have identified a novel interaction between T1DM and ductal cells. Presumably, the increased ductal secretion represents a defence mechanism in the prevention of diabetes, but further studies are needed to clarify this issue.

Neuronal and hormonal control of Ca2+ signalling in exocrine glands: insight from in vivo studies.

Fluid and enzyme secretion from exocrine glands is initiated by Ca2+ signalling in acinar cells and is activated by external neural or hormonal signals. A wealth of information has been derived from studies in acutely isolated exocrine cells but Ca2+ signalling has until recently not been studied in undisrupted intact tissue in live mice. Our in vivo observations using animals expressing genetically encoded Ca2+ indicators in specific cell types in exocrine glands revealed both similarities to and differences from the spatiotemporal characteristics previously reported in isolated cells. These in vivo studies facilitate further understanding of how both neuronal and hormonal input shapes Ca2+ signalling events in a physiological setting and how these signals are translated into the stimulation of fluid secretion and exocytosis.

AGA Clinical Practice Update on the Epidemiology, Evaluation, and Management of Exocrine Pancreatic Insufficiency: Expert Review.

DESCRIPTION: Exocrine pancreatic insufficiency (EPI) is a disorder caused by the failure of the pancreas to deliver a minimum/threshold level of specific pancreatic digestive enzymes to the intestine, leading to the maldigestion of nutrients and macronutrients, resulting in their variable deficiencies. EPI is frequently underdiagnosed and, as a result, patients are often not treated appropriately. There is an urgent need to increase awareness of and treatment for this condition. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update Expert Review was to provide Best Practice Advice on the epidemiology, evaluation, and management of EPI. METHODS: This Expert Review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. These Best Practice Advice statements were drawn from a review of the published literature and from expert opinion. Because systematic reviews were not performed, these Best Practice Advice statements do not carry formal ratings regarding the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: EPI should be suspected in patients with high-risk clinical conditions, such as chronic pancreatitis, relapsing acute pancreatitis, pancreatic ductal adenocarcinoma, cystic fibrosis, and previous pancreatic surgery. BEST PRACTICE ADVICE 2: EPI should be considered in patients with moderate-risk clinical conditions, such as duodenal diseases, including celiac and Crohn's disease; previous intestinal surgery; longstanding diabetes mellitus; and hypersecretory states (eg, Zollinger-Ellison syndrome). BEST PRACTICE ADVICE 3: Clinical features of EPI include steatorrhea with or without diarrhea, weight loss, bloating, excessive flatulence, fat-soluble vitamin deficiencies, and protein-calorie malnutrition. BEST PRACTICE ADVICE 4: Fecal elastase test is the most appropriate initial test and must be performed on a semi-solid or solid stool specimen. A fecal elastase level <100 µg/g of stool provides good evidence of EPI, and levels of 100-200 µg/g are indeterminate for EPI. BEST PRACTICE ADVICE 5: Fecal elastase testing can be performed while on pancreatic enzyme replacement therapy. BEST PRACTICE ADVICE 6: Fecal fat testing is rarely needed and must be performed when on a high-fat diet. Quantitative testing is generally not practical for routine clinical use. BEST PRACTICE ADVICE 7: Response to a therapeutic trial of pancreatic enzymes is unreliable for EPI diagnosis. BEST PRACTICE ADVICE 8: Cross-sectional imaging methods (computed tomography scan, magnetic resonance imaging, and endoscopic ultrasound) cannot identify EPI, although they play an important role in the diagnosis of benign and malignant pancreatic disease. BEST PRACTICE ADVICE 9: Breath tests and direct pancreatic function tests hold promise, but are not widely available in the United States. BEST PRACTICE ADVICE 10: Once EPI is diagnosed, treatment with pancreatic enzyme replacement therapy (PERT) is required. If EPI is left untreated, it will result in complications related to fat malabsorption and malnutrition, having a negative impact on quality of life. BEST PRACTICE ADVICE 11: PERT formulations are all derived from porcine sources and are equally effective at equivalent doses. There is a need for H2 or proton pump inhibitor therapy with non-enteric-coated preparations. BEST PRACTICE ADVICE 12: PERT should be taken during the meal, with the initial treatment of at least 40,000 USP units of lipase during each meal in adults and one-half of that with snacks. The subsequent dosage can be adjusted based on the meal size and fat content. BEST PRACTICE ADVICE 13: Routine supplementation and monitoring of fat-soluble vitamin levels are appropriate. Dietary modifications include a low-moderate fat diet with frequent smaller meals and avoiding very-low-fat diets. BEST PRACTICE ADVICE 14: Measures of successful treatment with PERT include reduction in steatorrhea and associated gastrointestinal symptoms; a gain of weight, muscle mass, and muscle function; and improvement in fat-soluble vitamin levels. BEST PRACTICE ADVICE 15: EPI should be monitored and baseline measurements of nutritional status should be obtained (body mass index, quality-of-life measure, and fat-soluble vitamin levels). A baseline dual-energy x-ray absorptiometry scan should be obtained and repeated every 1-2 years.

Metabolic Sequelae: The Pancreatitis Zeitgeist of the 21st Century.

Holistic management of pancreatitis means that gastroenterologists in the 21st Century should think beyond improving in-hospital outcomes of pancreatitis alone. In particular, there is considerable room for optimizing the management of new-onset diabetes, exocrine pancreatic insufficiency, and other metabolic sequelae of pancreatitis. The present article provides state-of-the-art information on classification, terminology, and burden of the common sequelae of pancreatitis. A high-risk group of patients with pancreatitis is identified, which is positioned to benefit the most from the metabolic sequelae surveillance program introduced in this article. The program involves continuous follow-up after pancreatitis diagnosis, with the focus on early identification of new-onset diabetes after pancreatitis and exocrine pancreatic insufficiency. The metabolic sequelae surveillance program is scalable and has the potential to reduce the burden of pancreatitis through tertiary prevention in the decades to come.

Gland Macrophages: Reciprocal Control and Function within Their Niche.

The human body contains dozens of endocrine and exocrine glands, which regulate physiological processes by secreting hormones and other factors. Glands can be subdivided into contiguous tissue modules, each consisting of an interdependent network of cells that together perform particular tissue functions. Among those cells are macrophages, a diverse type of immune cells endowed with trophic functions. In this review, we discuss recent findings on how resident macrophages support tissue modules within glands via the creation of mutually beneficial cell-cell circuits. A better comprehension of gland macrophage function and local control within their niche is essential to achieve a refined understanding of gland physiology in homeostasis and disease.

Alterations in exocrine pancreatic function after acute pancreatitis.

Exocrine pancreatic dysfunction (EPD) is a malabsorptive complication of pancreatic disorders that can lead to a host of symptoms ranging from flatulence to diarrhea and contribute to weight loss and metabolic bone disease. It is increasingly recognized to occur after acute pancreatitis (AP), including episodes with mild severity. The risk of developing EPD after AP is influenced by a range of factors, including the degree of acinar cell destruction and inflammation during AP, and persistent structural derangements following AP. In this article, we discuss the epidemiology, pathophysiology, and clinical management of EPD after AP while highlighting key knowledge gaps.

Correlation between endoscopic ultrasound features and exocrine pancreatic function in chronic pancreatitis.

BACKGROUND: Endoscopic ultrasound (EUS) is the most sensitive method for diagnosing chronic pancreatitis (CP) in its early stages, and Rosemont Classification (RC) is used for its evaluation. Data on the correlation between EUS features and pancreatic exocrine insufficiency (PEI) are limited. We investigated the correlation between the EUS findings and PEI. METHODS: This was a retrospective, monocentric cohort study involving patients prospectively enrolled from 2018 to 2022, with definite or probable CP according to the M-ANNHEIM criteria. All the patients underwent EUS and exocrine function investigations within 12 months of diagnosis. PEI was diagnosed using fecal elastase (FE) or when overt steatorrhea was reversed by pancreatic enzyme replacement therapy. Logistic regression analyses, rank correlation, ROC curve, and area under the curve (AUROC) were performed to evaluate the association between EUS features and PEI, and the accuracy of RC in predicting PEI. RESULTS: Among 128 patients examined (63.3 % male; mean age, 47 years), 69.5 % were diagnosed with PEI. In multivariate logistic regression among all the RC criteria, only lithiasis in the main pancreatic duct (MPD) was associated with increased risk of PEI (OR 2.92, 95 % CI 1.29-6.61; p = 0.01). Rank analysis showed a weak inverse correlation between RC and FE (Spearman's rho = -0.02; p = 0.03). The accuracy of RC was moderate (AUROC 0.62, p = 0.014). CONCLUSIONS: Among RC EUS features, lithiasis in the MPD is helpful for predicting the risk of PEI, while other findings are of limited utility in evaluating exocrine function.

Comprehensive, long-term evaluation of pancreatic exocrine insufficiency after pancreatoduodenectomy.

AIMS: Treatment of pancreatic exocrine insufficiency (PEI) following pancreatoduodenectomy (PD) improves quality of life, clinical outcomes, and survival. However, diagnosing PEI following PD is challenging owing to the difficulties with current tests and often non-specific symptoms. This work aims to quantify the true rate of long-term PEI in patients following a PD. METHODS: Patients underwent a PEI screen approximately one to two years following PD for oncologic indication, including the 13C Mixed triglyceride breath test (13CMTGT), faecal elastase 1 (FE-1) and the PEI Questionnaire (PEI-Q). Four reviewers with expertise in PEI reviewed the results blinded to other decisions to classify PEI status; disagreements were resolved on consensus. RESULTS: 26 patients were recruited. Of those with valid test results, these were indicative of PEI based on pre-specified thresholds for 60 % (15/25) for the 13CMTGT, 82 % (18/22) for FE-1, and 88 % (22/25) for the PEI-Q. After discussion between reviewers, the consensus PEI prevalence was 81 % (95 % CI: 61-93 %; 21/26), with 50 % (N = 13) classified as having severe, 23 % (N = 6) moderate, and 8 % (N = 2) mild PEI. DISCUSSION: Since no ideal test exists for PEI, this collation of diagnostic modalities and blinded expert review was designed to ascertain the true rate of long-term PEI following PD. This required our cohort to survive a year, travel to hospital, and undergo a period of starvation and PERT hold, and therefore there is likely to be recruitment bias towards fitter, younger patients with less aggressive pathology. Despite this, over 80 % were deemed to have PEI, with over 90 % of these being considered moderate or severe.

The effect of steroid therapy on pancreatic exocrine function in autoimmune pancreatitis.

BACKGROUND/OBJECTIVES: Autoimmune pancreatitis (AIP) is a steroid-responsive inflammatory disease of the pancreas. Few studies investigated pancreatic exocrine function (PEF) in patients suffering from AIP and no definitive data are available on the effect of steroids in PEF recovery. Aim of the study is the evaluation of severe pancreatic insufficiency (sPEI) prevalence in AIP at clinical onset and after steroid treatment. METHODS: 312 Patients with diagnosis of AIP between January 1st, 2010 and December 31st, 2020 were identified in our prospectively maintained register. Patients with a pre-steroid treatment dosage of fecal elastase-1 (FE-1) were included. Changes in PEF were evaluated in patients with available pre- and post-treatment FE (between 3 and 12 months after steroid). RESULTS: One-hundred-twenty-four patients were included, with a median FE-1 of 122 (Q1-Q3: 15-379) µg/g at baseline. Fifty-nine (47.6 %) had sPEI (FE-1<100 µg/g). Univariable analysis identified type 1 AIP, radiological involvement of the head of the pancreas (diffuse involvement of the pancreas or focal involvement of the head), weight loss, age and diabetes as associated with a greater risk of sPEI. However, at multivariable analysis, only the involvement of the head of the pancreas was identified as independent risk factor for sPEI. After steroids, mean FE-1 changed from 64 (15-340) to 202 (40-387) µg/g (P = 0.058) and head involvement was the only predictor of improvement of sPEI. CONCLUSION: The inflammatory involvement of the head of the pancreas is associated with PEF severity, as well as PEF improvement after treatment with steroids in patients with AIP.

Skeletal muscle mass and function are affected by pancreatic atrophy, pancreatic exocrine insufficiency and poor nutritional status in patients with chronic pancreatitis.

BACKGROUND/OBJECTIVE: Previous studies have demonstrated that sarcopenia is frequently observed in patients with chronic pancreatitis (CP). However, most studies have defined sarcopenia solely based on skeletal muscle (SM) loss, and muscle weakness such as grip strength (GS) reduction has not been considered. We aimed to clarify whether SM loss and reduced GS have different associations with clinical characteristics and pancreatic imaging findings in patients with CP. METHODS: One hundred two patients with CP were enrolled. We defined SM loss by the SM index at the third lumbar vertebra on CT (<42 cm2/m2 for males and <38 cm2/m2 for females), and reduced GS by < 28 kg for males and <18 kg for females. RESULTS: Fifty-seven (55.9 %) patients had SM loss, 21 (20.6 %) had reduced GS, and 17 (16.7 %) had both. Patients with SM loss had lower body mass index, weaker GS, higher Controlling Nutritional Status score, lower serum lipase level, and lower urinary para-aminobenzoic acid excretion rate, suggesting worse nutritional status and pancreatic exocrine insufficiency. On CT, main pancreatic duct dilatation and parenchymal atrophy were more frequent in patients with SM loss than in those without it. Patients with reduced GS were older and had worse nutritional status than those without it. CONCLUSIONS: SM loss was associated with pancreatic exocrine insufficiency, low nutritional status, and pancreatic imaging findings such as parenchymal atrophy and main pancreatic duct dilatation, whereas older age and low nutritional status led to additional reduced GS.