Iron metabolism and the exocrine pancreas

The Modulation of Euglycemic Endocrine and Exocrine Pancreatic Secretions in Iron Deficiency

OBJECTIVES

The contribution of pancreatic secretions in iron metabolism has been elucidated, but the clinical outcomes of iron deficiency on pancreatic function are debatable. This study aimed to investigate the modulation of euglycemic endocrine and exocrine pancreatic excretions in response to variations in iron availability.

SUBJECTS AND METHODS

Serum levels of insulin, glucagon, insulin-to-glucagon ratio (IGR), and amylase were determined in 170 adult subjects with variable levels of serum iron.

RESULTS

Control (n = 46) and iron-deficient (n = 124) subjects had significant differences (p < 0.001) in their average levels of insulin (68.7 ± 0.5 vs. 100.0 ± 2.0 pmol/dL), glucagon (17.9 ± 0.6 vs. 10.8 ± 0.8 pmol/dL), IGR (4.0 ± 0.1 vs. 19.5 ± 2.1), and amylase (29.7 ± 0.9 vs. 17.5 ± 0.2). The upregulation of serum insulin levels increases proportionally and gradually to the extent of iron deficiency as compared to an abrupt downregulation of serum levels of glucagon and amylase. A significant association was observed between serum iron and IGR (r = -0.645, p < 0.001) and amylase levels (r = 0.653, p < 0.001). The receiver operating characteristic curve analysis defines an excellent predictivity of the reduced serum iron level to discriminate subjects with upregulated IGR and amylase levels with area under curves of 0.938 and 0.905, respectively.

CONCLUSION

Iron deficiency is associated with an adaptive modulation of euglycemic endocrine and exocrine secretions that is consistent with a status of insulin resistance.

Ionomic Variation Among Tissues in Fallow Deer (Dama dama) by Sex and Age

(1) In mammals, the mineral nutrient and trace elemental composition of the body - the ionome - differs among individuals. It has been hypothesized that these differences may be related to age and sex, both for ecotoxic and essential elements. (2) We investigated whether and how intraspecific ionomic variation is related to age and sex in Fallow deer (Dama dama). We tested the predictions that concentrations of ecotoxic elements increase with age, that ionomic variation is lower among young individuals than among older individuals, and that reproductive females (does) have the lowest concentrations of essential elements. (3) Culled animals of different sex and age were obtained from a single protected area. The animals were dissected to collect 13 tissues, and concentrations of 22 different elements were measured in a sample of each tissue. (4) We described substantial ionomic variation between individuals. Some of this variation was related to age and sex, as predicted. Based on the limited existing knowledge on chemical element allocation and metabolism in the body, sex-related differences were more difficult to interpret than age-related differences. Since reference values are absent, we could not judge about the consequences of the elemental values that we found. (5) More extensive ionomic surveys, based on a wide range of elements and tissues, are needed to enlarge the understanding of within-species ionomic variation and potential biological, ecological, and metabolic consequences.

Associations of pancreas fat content and size with markers of iron metabolism

OBJECTIVE

To comprehensively investigate the associations of pancreas fat content and size with circulating markers of iron metabolism.

METHODS

A total of 116 individuals underwent magnetic resonance imaging and spectroscopy on a 3.0 Tesla scanner, exclusively for the purpose of the COSMOS research programme. Intra-pancreatic fat deposition, total pancreas volume, liver fat content, visceral and subcutaneous fat volumes were quantified. Plasma levels of hepcidin and ferritin were measured. Multiple linear regression analysis was conducted, adjusting for body mass index, age, and sex.

RESULTS

Total intra-pancreatic fat deposition was inversely associated with hepcidin (β = -0.54, 95 % confidence interval -1.02 to -0.07) whereas total pancreas volume was not associated with hepcidin (β = 0.36, 95 % confidence interval -7.12 to 7.84) in the most adjusted model. Neither total intra-pancreatic fat deposition (β = -0.03, 95 % confidence interval -0.39 to 0.33) nor total pancreas volume (β = -1.02, 95 % confidence interval -6.67 to 4.63) was associated with ferritin in the most adjusted model. Subcutaneous fat, visceral fat, and liver fat were not associated with hepcidin. Subcutaneous fat was inversely associated with ferritin (β = -0.06, 95 % CI -0.11 to -0.01) whereas visceral fat (β = 0.05, 95 % CI -0.01 to 0.14) and liver fat (β = 0.09, 95 % CI -0.04 to 0.34) were not associated with ferritin in the most adjusted model.

CONCLUSIONS

Increased intra-pancreatic fat deposition, but not other fat depots, is associated with reduced circulating levels of hepcidin. Deranged iron metabolism may play a role in the pathogenesis of fatty change of the pancreas.

Ferroptosis: potential targets and emerging roles in pancreatic diseases

Ferroptosis is a newly discovered form of regulatory cell death characterized by excessive iron-dependent lipid peroxidation. In the past decade, significant breakthroughs have been made in comprehending the features and regulatory mechanisms of ferroptosis, and it has been confirmed that ferroptosis plays a pivotal role in the pathophysiological processes of various diseases, including tumors, inflammation, neurodegenerative diseases, and infectious diseases. The pancreas, which is the second largest digestive gland in the human body and has both endocrine and exocrine functions, is a vital organ for controlling digestion and metabolism. In recent years, numerous studies have confirmed that ferroptosis is closely related to pancreatic diseases, which is attributed to abnormal iron accumulation, as an essential biochemical feature of ferroptosis, is often present in the pathological processes of various pancreatic exocrine and endocrine diseases and the vulnerability of the pancreas to oxidative stress stimulation and damage. Therefore, comprehending the regulatory mechanism of ferroptosis in pancreatic diseases may provide valuable new insights into treatment strategies. In this review, we first summarize the hallmark features of ferroptosis and then analyze the exact mechanisms by which ferroptosis is precisely regulated at multiple levels and links, including iron metabolism, lipid metabolism, the GPX4-mediated ferroptosis defense system, the GPX4-independent ferroptosis defense system, and the regulation of autophagy on ferroptosis. Finally, we discuss the role of ferroptosis in the occurrence and development of pancreatic diseases and summarize the feasibility and limitations of ferroptosis as a therapeutic target for pancreatic diseases.

From diabetic hyperglycemia to cerebrovascular Damage: A narrative review

Diabetes mellitus is a globally significant disease that can lead to systemic complications, particularly vascular damage, including cardiovascular and cerebrovascular diseases of relevance. The physiological changes resulting from the imbalance in blood glucose levels play a crucial role in initiating vascular endothelial damage. Elevated glucose levels can also penetrate the central nervous system, triggering diabetic encephalopathy characterized by oxidative damage to brain components and activation of alternative and neurotoxic pathways. This brain damage increases the risk of ischemic stroke, a leading cause of mortality worldwide and a major cause of disability among surviving patients. The aim of this review is to highlight important pathways related to hyperglycemic damage that extend to the brain and result in vascular dysfunction, ultimately leading to the occurrence of a stroke. Understanding how diabetes mellitus contributes to the development of ischemic stroke and its impact on patient outcomes is crucial for implementing therapeutic strategies that reduce the incidence of diabetes mellitus and its complications, ultimately decreasing morbidity and mortality associated with the disease.

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.

Sirtuin4 alleviates severe acute pancreatitis by regulating HIF-1α/HO-1 mediated ferroptosis

Acute pancreatitis (AP) is a common emergency of the digestive system and serious cases can develop into severe acute pancreatitis (SAP), which ortality rates up to 30%. Sirtuin4 (SIRT4) is a member of the sirtuin family, and plays a key role in inflammation and oxidative stress. However, the potential role of SIRT4 in SAP has yet to be elucidated. In the present study, we found that the expression level of SIRT4 in human AP was downregulated by screening a public database, suggesting that SIRT4 may play a role in AP. Subsequently, we used L-arginine (L-Arg) to induce SAP in SIRT4 knockout (SIRT4_KO) and SIRT4 overexpression (AAV_SIRT4) mice. The results showed that the pancreatic tissue injury and related lung and kidney injury were serious in SIRT4_KO mice after SAP induction, but were significantly reduced in AAV_SIRT4 mice. More importantly, we found that the levels of antioxidant factors GSH and SOD were decreased in SIRT4_KO mice, and the production of oxidative products and lipid peroxidation markers was increased, suggesting that SIRT4 was involved in inflammation and oxidative stress during SAP. Further studies showed that the absence or overexpression of SIRT4 affected the expression level of Hypoxia-inducible factor-1α (HIF-1α) after SAP induction, and regulated the expression of ferroptosis related proteins by mediating HIF-1α/HO-1 pathway. Collectively, our study revealed that SIRT4 plays a protective role in SAP by regulating the HIF-1α/HO-1 pathway to inhibit ferroptosis.

Relationship of Iron Intake, Ferritin, and Hepcidin with the Transverse Relaxation Rate of Water Protons in the Pancreas

(1) Background: There is a paucity of markers of iron metabolism in health and disease. The aim was to investigate the associations of iron metabolism with pancreas transverse water proton relaxation rate (R2water) in healthy individuals and people after an attack of pancreatitis. (2) Methods: All participants underwent a 3.0 T magnetic resonance imaging of the abdomen on the same scanner. High-speed T2-corrected multi-echo (HISTO) acquisition at single-voxel magnetic resonance spectroscopy and inline processing were used to quantify pancreas R2water. Habitual dietary intake of iron was determined using the EPIC-Norfolk food frequency questionnaire. Circulating levels of ferritin and hepcidin were measured. Generalised additive models were used, adjusting for age, sex, body mass index, and haemoglobin A1c. (3) Results: A total of 139 individuals (47 healthy individuals, 54 individuals after acute pancreatitis, and 38 individuals after chronic pancreatitis) were included. Total dietary intake of iron was significantly associated with pancreas R2water, consistently in healthy individuals (p < 0.001), individuals after acute pancreatitis (p < 0.001), and individuals after chronic pancreatitis (p < 0.001) across all the statistical models. Ferritin was significantly associated with pancreas R2water, consistently in healthy individuals (p < 0.001), individuals after acute pancreatitis (p < 0.001), and individuals after chronic pancreatitis (p = 0.01) across all adjusted models. Hepcidin was significantly associated with pancreas R2water in individuals after acute pancreatitis (p < 0.001) and individuals after chronic pancreatitis (p = 0.04) in the most adjusted model. (4) Conclusions: Pancreas R2water, corrected for T2, is related to iron metabolism in both health and pancreatitis. This non-invasive marker could be used for automated in vivo identification of intra-pancreatic iron deposition.

New insights into regulatory cell death and acute pancreatitis

Acute pancreatitis (AP) may be associated with both local and systemic complications. Although it is usually self-limiting, up to 20% of patients develop severe acute pancreatitis (SAP), which leads to systemic inflammatory response syndrome (SIRS) and multiorgan dysfunction and failure affecting the lung, kidney, liver and heart. Patients who survive the condition frequently develop devastating long-term consequences such as diabetes mellitus, exocrine pancreatic insufficiency, chronic pancreatitis (CP) and poor quality of life. A lack of specific targeted treatments is the main reason for high mortality and morbidity, indicating that more research on the pathogenesis of AP is needed. In the past decade, substantial advancements have been made in our understanding of the pathophysiological mechanisms of AP, including mechanisms of calcium-mediated acinar cell injury and death, the cytoprotective role of the unfolded protein response (UPR) and autophagy in preventing sustained endoplasmic reticulum stress (ERs); however, the mechanism of parenchymal cell death is relatively poorly understood. This paper reviews the research progress of the regulatory cell death (RCD) mode in the pathogenesis of AP, providing some new insights and regulatory targets for the pathogenesis and treatment of AP, facilitating better targeted drug development.

The biology of mammalian multi-copper ferroxidases

The mammalian multicopper ferroxidases (MCFs) ceruloplasmin (CP), hephaestin (HEPH) and zyklopen (ZP) comprise a family of conserved enzymes that are essential for body iron homeostasis. Each of these enzymes contains six biosynthetically incorporated copper atoms which act as intermediate electron acceptors, and the oxidation of iron is associated with the four electron reduction of dioxygen to generate two water molecules. CP occurs in both a secreted and GPI-linked (membrane-bound) form, while HEPH and ZP each contain a single C-terminal transmembrane domain. These enzymes function to ensure the efficient oxidation of iron so that it can be effectively released from tissues via the iron export protein ferroportin and subsequently bound to the iron carrier protein transferrin in the blood. CP is particularly important in facilitating iron release from the liver and central nervous system, HEPH is the major MCF in the small intestine and is critical for dietary iron absorption, and ZP is important for normal hair development. CP and HEPH (and possibly ZP) function in multiple tissues. These proteins also play other (non-iron-related) physiological roles, but many of these are ill-defined. In addition to disrupting iron homeostasis, MCF dysfunction perturbs neurological and immune function, alters cancer susceptibility, and causes hair loss, but, despite their importance, how MCFs co-ordinately maintain body iron homeostasis and perform other functions remains incompletely understood.

High Dietary Iron in Western Diet-Fed Male Rats Causes Pancreatic Islet Injury and Acute Pancreatitis

BACKGROUND

High dietary iron has been linked to an increased type 2 diabetes risk. We have previously shown that intrauterine growth restriction (IUGR) and feeding a Western diet (WD) to male Sprague-Dawley rats independently, as well as together, cause pancreatic islet inflammation, fibrosis, and hemosiderosis.

OBJECTIVES

To investigate whether iron has a role in the pathogenesis of this inflammatory islet injury caused by IUGR and WD intake.

METHODS

Male Sprague-Dawley offspring of bilateral uterine artery ligated (IUGR) and sham-operated (Sham) dams, fostered to nonoperated dams, were fed a WD [45% sucrose, 19.4% protein and 23% fat (w/w)] containing low iron (LI, 20 mg/kg) or high iron (HI, 500 mg/kg) from weaning. Four groups were studied: Sham-LI, Sham-HI, IUGR-LI, and IUGR-HI. Serial measurements of rat body weight, blood glucose, lipids and insulin, an intraperitoneal glucose tolerance test (age 13 wk), and histological analysis of pancreas and liver (age 14 wk) were recorded. The effects of iron, IUGR, and their interaction, on these measurements have been analyzed.

RESULTS

WD with HI compared with LI caused an 11% greater weight gain by age 14 wk (P < 0.001), impaired glucose tolerance [AUC for glucose (G-AUC) 17% higher; P < 0.001), acute pancreatitis (17/18, HI; 6/17, LI; P < 0.001), pancreas-associated fat necrosis and saponification (7/18, HI; 0/17 LI; P < 0.01), and a trend to islet fibrotic injury (7/18, HI; 1/17 LI; P = 0.051). Although pancreatic and hepatic steatosis was evident in almost all WD-fed rats, pancreatic and hepatic iron accumulation was prevalent only in HI-fed rats (P < 0.0001 for both), being only mild in the livers. IUGR, independent of dietary iron, also caused impairment in glucose tolerance (G-AUC: 17% higher; P < 0.05).

CONCLUSIONS

A postweaning WD containing HI, independent of IUGR, causes acute pancreatitis and islet injury in Sprague-Dawley rats suggesting a role of dietary iron in the development of steatopancreatitis.

Identifying endotypes of individuals after an attack of pancreatitis based on unsupervised machine learning of multiplex cytokine profiles

After an attack of pancreatitis, individuals may develop metabolic sequelae (eg, new-onset diabetes) and/or pancreatic cancer. These new-onset morbidities are, at least in part, driven by low-grade inflammation. The aim was to study the profiles of cytokines/chemokines in individuals after an attack of pancreatitis. A commercially available panel including 31 cytokines/chemokines was investigated. Random forest classifier and unsupervised hierarchical clustering were applied to study participants (who had no persistent organ failure and did not require ICU admission) according to their cytokine/chemokine profiles. Pancreatitis-related characteristics, detailed body composition (determined using 3.0 T magnetic resonance imaging), markers of glucose, lipid, and iron metabolism, gut and pancreatic hormones, as well as liver and pancreatic enzymes, were compared between clusters. Bootstrap validation was employed. A total of 160 participants, including 107 postpancreatitis individuals (investigated at a median of 18 months after the last attack of pancreatitis) and 53 healthy volunteers, were studied. Twenty-two cytokines/chemokines were significantly different between postpancreatitis and health. Two distinct endotypes of individuals after an attack of pancreatitis were identified-‟inflammatory" and ‟noninflammatory." Sixteen cytokines/chemokines were significantly higher in the inflammatory endotype compared with the noninflammatory endotype. No cytokine/chemokine was significantly higher in the noninflammatory endotype. The inflammatory endotype was characterized by significantly elevated insulin (P= 0.001), glucose-dependent insulinotropic peptide (P = 0.001), peptide YY (P = 0.017), and ghrelin (P = 0.014). The noninflammatory endotype was characterized by significantly elevated hepcidin (P= 0.016). Pancreatitis-related factors, body composition, and other studied parameters did not differ significantly between the 2 endotypes. Individuals with a similar phenotype and clinical course of pancreatitis have differing cytokine/chemokine profiles after clinical resolution of the disease. People with the inflammatory endotype have distinct changes in the pancreatic and gut hormones known to be involved in the pathogenesis of new-onset morbidities after an attack of pancreatitis.

Identification of AP-1 as a Critical Regulator of Glutathione Peroxidase 4 (GPX4) Transcriptional Suppression and Acinar Cell Ferroptosis in Acute Pancreatitis

Glutathione peroxidase 4 (GPX4)-dependent ferroptosis in pancreatic acinar cells plays a critical role in acute pancreatitis (AP). However, potential upstream regulators of GPX4 are not well defined. Here, we observed a marked reduction in acinar GPX4 expression and ferroptotic cell death in mice with cerulein-induced AP. To determine the critical factors involved in acinar cell ferroptosis, pancreas transcriptome data from an AP mouse model were analyzed and overlapped with predicted transcription factors of Gpx4, and an upregulated transcription factor active protein 1 (AP-1) protein, Jun, was identified. The administration of a specific ferroptosis inhibitor liproxstatin-1 alleviated AP pathology and significantly decreased Jun levels. Bioinformatic analysis indicated that the Gpx4 promoter contains a putative AP-1 binding site. Jun binds directly to the Gpx4 promoter and inhibits Gpx4 transcription under pancreatic conditions. AP-1 inhibition by a selective inhibitor SR11302 reversed GPX4 reduction and ameliorated AP pathology in a GPX4-dependent manner. Collectively, our study demonstrates that the downregulation of GPX4 by AP-1 is critical in the aggravation of acinar cell ferroptosis during the progression of AP. Strategies targeting the AP-1/GPX4 axis may be potentially effective for the prevention and treatment of AP.

Associations Between Iron Homeostasis and Pancreatic Enzymes After an Attack of Pancreatitis

OBJECTIVES

Dysregulation of iron homeostasis and exocrine pancreatic dysfunction are linked but remain undefined in individuals with a history of pancreatitis. The objective is to investigate the relationship between iron homeostasis and pancreatic enzymes in individuals after a pancreatitis attack.

METHODS

This was a cross-sectional study of adults with a history of pancreatitis. Markers of iron metabolism (hepcidin and ferritin) and pancreatic enzymes (pancreatic amylase, pancreatic lipase, and chymotrypsin) were measured in venous blood. Habitual dietary iron intake data (total, heme, and nonheme iron) were collected. Multivariable linear regression analyses were performed while considering covariates.

RESULTS

One hundred and one participants were studied at a median of 18 months after their last pancreatitis attack. Hepcidin was significantly associated with pancreatic amylase (β coefficient, -6.68; 95% confidence interval, -12.88 to -0.48; P = 0.035) and heme iron intake (β coefficient, 0.34; 95% confidence interval, 0.08 to 0.60; P = 0.012) in the adjusted model. Hepcidin was not significantly associated with pancreatic lipase or chymotrypsin. Ferritin was not significantly associated with pancreatic enzymes and dietary iron intake.

CONCLUSIONS

An iron homeostasis-exocrine pancreas crosstalk exists in individuals after an attack of pancreatitis. The role of iron homeostasis in pancreatitis warrants high-quality purposely-designed studies.

Ferroptosis and its emerging roles in acute pancreatitis

ABSTRACT

Acute pancreatitis (AP) is a common and potentially life-threatening pancreatic inflammatory disease. Although it is usually self-limiting, up to 20% of patients will develop into severe AP. It may lead to systemic inflammatory response syndrome and multiple organ dysfunction, affecting the lungs, kidneys, liver, heart, etc. Surviving patients usually have sequelae of varying degrees, such as chronic hyperglycemia after AP (CHAP), pancreatic exocrine insufficiency, and chronic pancreatitis. Lacking specific target treatments is the main reason for high mortality and morbidity, which means that more research on the pathogenesis of AP is needed. Ferroptosis is a newly discovered regulated cell death (RCD), originally described in cancer cells, involving the accumulation of iron and the depletion of plasma membrane polyunsaturated fatty acids, and a caspase-independent RCD. It is closely related to neurological diseases, myocardial infarction, ischemia/reperfusion injury, cancer, etc. Research in the past years has also found the effects of ferroptosis in AP, pancreatic cancer, and AP complications, such as acute lung injury and acute kidney injury. This article reviews the research progress of ferroptosis and its association with the pathophysiological mechanisms of AP, trying to provide new insight into the pathogenesis and treatment of AP, facilitating the development of better-targeted drugs.

Pancreatic iron quantification with MR imaging: a practical guide

Accurate determination of pancreatic iron status is crucial for preventing impairment of the exocrine and endocrine function of the pancreas and for prospectively stratifying the cardiac iron risk. The following article should be a sort of practical guide for radiologists interested in quantifying pancreatic iron overload by Magnetic Resonance Imaging (MRI). After a brief background on iron-deposition diseases, we will describe basic principles and relative advantages and disadvantages of the more widely used and clinically feasible MRI-based techniques for pancreatic iron assessment. These methods can be classified into signal intensity ratio (SIR) and relaxometry methods. We will examine different technical aspects representing the key for accurate and precise relaxation time measurement.

Adipose triglyceride lipase mediates lipolysis and lipid mobilization in response to iron-mediated negative energy balance

Maintenance of energy balance is essential for overall organismal health. Mammals have evolved complex regulatory mechanisms that control energy intake and expenditure. Traditionally, studies have focused on understanding the role of macronutrient physiology in energy balance. In the present study, we examined the role of the essential micronutrient iron in regulating energy balance. We found that a short course of dietary iron caused a negative energy balance resulting in a severe whole body wasting phenotype. This disruption in energy balance was because of impaired intestinal nutrient absorption. In response to dietary iron-induced negative energy balance, adipose triglyceride lipase (ATGL) was necessary for wasting of subcutaneous white adipose tissue and lipid mobilization. Fat-specific ATGL deficiency protected mice from fat wasting, but caused a severe cachectic response in mice when fed iron. Our work reveals a mechanism for micronutrient control of lipolysis that is necessary for regulating mammalian energy balance.

Prevalence of Chronic Metabolic Comorbidities in Acute Pancreatitis and Its Impact on Early Gastrointestinal Symptoms during Hospitalization: A Prospective Cohort Study

Background

The prevalence of chronic comorbidities is increasing worldwide, and this has been paralleled by a growing interest in how these comorbidities affect patients with acute pancreatitis. The aim was to investigate the associations between pre-existing diabetes mellitus, obesity, metabolic syndrome, and gastrointestinal symptoms during the early course of acute pancreatitis.

Methods

This was a prospective cohort study of patients with a primary diagnosis of acute pancreatitis. Study groups were formed based on the presence of metabolic comorbidities (pre-existing diabetes mellitus, obesity, and metabolic syndrome). Patient-reported outcomes (nausea, bloating, and abdominal pain) were collected prospectively every 24 h (including weekends and public holidays) over the first 72 h of hospitalization.

Results

A total of 183 consecutive patients were enrolled. Of them, 111 (61%) had at least one major metabolic comorbidity. Patients with pre-existing diabetes mellitus and those with metabolic syndrome had worse nausea at 49-72 h of hospitalization (p = 0.017 and p = 0.012, respectively), but not at other time points. Bloating and abdominal pain did not differ between the study groupings throughout the study period. The studied patient-reported outcomes did not differ significantly between acute pancreatitis patients with and without obesity at any point in time.

Conclusion

More than 3 out of 5 patients hospitalized for acute pancreatitis have at least one major chronic metabolic comorbidity. The presence of metabolic comorbidities does not considerably and consistently affect early gastrointestinal symptoms in patients with acute pancreatitis.

Iron-Storage Disorder Presenting as Chronic Diarrhea

The involvement of the endocrine pancreas leading to bronze diabetes is well studied. However, little is known about the pathophysiology of iron dysregulation involving the exocrine pancreas. We present a unique association between the exocrine pancreas and iron dysregulation. A 45-year-old female presented with chronic diarrhea and low fecal elastase indicative of pancreatic exocrine dysfunction. MRI of the abdomen/pelvis showed iron deposition in the pancreas, suggesting an associated iron-storage disorder without features suggesting chronic pancreatitis. Association of an iron-storage disorder with pancreatic exocrine dysfunction has been reported only in one other case report. Pancreatic exocrine dysfunction can be directly associated with an iron-storage disorder that involves the pancreas. This should be included in the differential and diagnostic work-up of chronic diarrhea of unclear etiology. Based on the literature, we have highlighted the potential pathophysiology relevant to the case.

Associations of Habitual Mineral Intake with New-Onset Prediabetes/Diabetes after Acute Pancreatitis

Associations between habitual dietary intake of minerals and glucose metabolism have been extensively studied in relation to metabolic disorders. However, similar research has yet to be conducted in individuals after acute pancreatitis (AP). The main aim was to investigate the associations between habitual intake of 13 minerals and glycaemic status: new-onset prediabetes/diabetes after AP (NODAP), pre-existing prediabetes/type 2 diabetes (T2DM), and normoglycaemia after AP (NAP). Associations between the dietary intake of minerals and markers of glucose metabolism (glycated haemoglobin and fasting plasma glucose) were also studied. The EPIC-Norfolk food frequency questionnaire was used in a cross-sectional fashion to determine the habitual intake of 13 dietary minerals. ANCOVA as well as multiple linear regression analyses were conducted and five statistical models were built to adjust for covariates. The study included 106 individuals after AP. In the NODAP group, intake of 4 minerals was significantly less when compared with the NAP group: iron (B = -0.076, p = 0.013), nitrogen (B = -0.066, p = 0.003), phosphorous (B = -0.046, p = 0.006), and zinc (B = -0.078, p = 0.001). Glycated haemoglobin was significantly associated with iodine intake (B = 17.763, p = 0.032) and manganese intake (B = -17.147, p = 0.003) in the NODAP group. Fasting plasma glucose was significantly associated with manganese intake (B = -2.436, p = 0.027) in the NODAP group. Habitual intake of minerals differs between individuals with NODAP, T2DM, and NAP. Prospective longitudinal studies and randomised controlled trials are now warranted to further investigate the associations between mineral intake and NODAP.

Relationship between Energy Balance and Circulating Levels of Hepcidin and Ferritin in the Fasted and Postprandial States

Markers of iron metabolism are altered in new-onset diabetes, but their relationship with metabolic signals involved in the maintenance of energy balance is poorly understood. The primary aim was to explore the associations between markers of iron metabolism (hepcidin and ferritin) and markers of energy balance (leptin, ghrelin, and the leptin/ghrelin ratio) in both the fasted and postprandial states. These associations were also studied in the sub-groups stratified by diabetes status. This was a cross-sectional study of individuals without disorders of iron metabolism who were investigated after an overnight fast and, in addition, some of these individuals underwent a mixed meal test to determine postprandial responses of metabolic signals. The associations between hepcidin, ferritin, and leptin, ghrelin, leptin/ghrelin ratio were studied using several multiple linear regression models. A total of 76 individuals in the fasted state and 34 individuals in the postprandial state were included. In the overall cohort, hepcidin was significantly inversely associated with leptin (in the most adjusted model, the β coefficient ± SE was −883.45 ± 400.94; p = 0.031) and the leptin/ghrelin ratio (in the most adjusted model, the β coefficient ± SE was −148.26 ± 61.20; p = 0.018) in the fasted state. The same associations were not statistically significant in the postprandial state. In individuals with new-onset prediabetes or diabetes (but not in those with normoglycaemia or longstanding prediabetes or diabetes), hepcidin was significantly inversely associated with leptin (in the most adjusted model, the β coefficient ± SE was −806.09 ± 395.44; p = 0.050) and the leptin/ghrelin ratio (in the most adjusted model, the β coefficient ± SE was −129.40 ± 59.14; p = 0.037). Leptin appears to be a mediator in the link between iron metabolism and new-onset diabetes mellitus. These findings add to the growing understanding of mechanisms underlying the derangements of glucose metabolism.

Effect of β-hydroxybutyrate monoester on markers of iron metabolism in new-onset prediabetes: findings from a randomised placebo-controlled trial

Background: People with prediabetes often have altered iron metabolism and may benefit from mild exogenous ketosis, which can now be successfully achieved thanks to recent developments in chemistry of food components. Objective: The objective was to investigate the effect of acute exogenous ketone monoester (β-hydroxybutyrate) on plasma levels of markers of iron metabolism in people with prediabetes. Methods: Eighteen participants with new-onset prediabetes after acute pancreatitis aged 18 years or above took part in randomised controlled cross-over trial in Auckland, New Zealand. After an overnight fast, participants consumed the exogenous ketone supplement or placebo. Blood samples were collected in the fasted state (0 minutes) and then serially every 30 minutes for 150 minutes. Both participants and study personnel were blinded to the intervention/placebo allocation. Repeated measures analysis of variance was performed using total area under the curve to determine the change in hepcidin and ferritin over time after consumption of the exogenous ketone supplement and placebo. Results: Consumption of the exogenous ketone supplement significantly elevated blood levels of β-hydroxybutyrate from 0.20 mmol L^-1 at baseline to 3.50 mmol L^-1 at 30 minutes (p < 0.05) and remained significantly elevated for the duration of the trial. The total area under the curve of hepcidin was 340.5 ± 121.1 ng mL^-1 after the exogenous ketone supplementation as compared with 343.2 ± 119.6 ng mL^-1 min^-1 after the use of placebo (p = 0.91). The total area under the curve of ferritin was 786.7 ± 129.1 ng mL^-1 min^-1 after the exogenous ketone supplementation as compared with 776.9 ± 131.4 ng mL^-1 min^-1 after the use of placebo (p = 0.10). Conclusion: Acute supplementation of β-hydroxybutyrate did not significantly affect the circulating levels of hepcidin or ferritin in people with prediabetes. Long-term effects of β-hydroxybutyrate warrant investigations in the future.

Trypsin-Mediated Sensitization to Ferroptosis Increases the Severity of Pancreatitis in Mice

BACKGROUND & AIMS

Pancreatitis is characterized by acinar cell death and persistent inflammation. Ferroptosis is a type of lipid peroxidation-dependent necrosis, which is negatively regulated by glutathione peroxidase 4. We studied how trypsin, a serine protease secreted by pancreatic acinar cells, affects the contribution of ferroptosis to triggering pancreatitis.

METHODS

In vitro, the mouse pancreatic acinar cell line 266-6 and mouse primary pancreatic acinar cells were used to investigate the effect of exogenous trypsin on ferroptosis sensitivity. Short hairpin RNAs were designed to silence gene expression, whereas a library of 1080 approved drugs was used to identify new ferroptosis inhibitors in 266-6 cells. In vivo, a Cre/LoxP system was used to generate mice with a pancreas-specific knockout of Gpx4 (Pdx1-Cre;Gpx4^flox/flox mice). Acute or chronic pancreatitis was induced in these mice (Gpx4^flox/flox mice served as controls) by cerulein injections or a Lieber-DeCarli alcoholic liquid diet. Pancreatic tissues, acinar cells, and serum were collected and analyzed by histology, immunoblot, quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, or immunohistochemical analyses.

RESULTS

Supraphysiological doses of trypsin (500 or 1000 ng/mL) alone did not trigger significant cell death in 266-6 cells and mouse primary pancreatic acinar cells, but did increase the sensitivity of these cells to ferroptosis upon treatment with cerulein, L-arginine, alcohol, erastin, or RSL3. Proteasome 26S subunit, non-adenosine triphosphatase 4-dependent lipid peroxidation caused ferroptosis in pancreatic acinar cells by promoting the proteasomal degradation of glutathione peroxidase 4. The drug screening campaign identified the antipsychotic drug olanzapine as an antioxidant inhibiting ferroptosis in pancreatic acinar cells. Mice lacking pancreatic Gpx4 developed more severe pancreatitis after cerulein infection or ethanol feeding than control mice. Conversely, olanzapine administration protected against pancreatic ferroptotic damage and experimental pancreatitis in Gpx4-deficient mice.

CONCLUSIONS

Trypsin-mediated sensitization to ferroptotic damage increases the severity of pancreatitis in mice, and this process can be reversed by olanzapine.

Association between Habitual Dietary Iron Intake and Glucose Metabolism in Individuals after Acute Pancreatitis

Dietary intake of iron is known to be associated with impaired glucose metabolism. However, its involvement in derangements of glucose metabolism after acute pancreatitis (AP) is not completely understood. The aim was to investigate the association between dietary iron intake and markers of glucose metabolism in individuals after an attack of AP. Fasting blood samples were collected to analyse markers of glucose metabolism (fasting plasma glucose (FPG) and haemoglobin A1c (HbA1c)). The EPIC-Norfolk food frequency questionnaire was used to determine the habitual intake of dietary iron (total, haem, and non-haem). Multivariable linear regression analyses were conducted and six statistical models were built to adjust for covariates. A total of 109 individuals after AP were studied in a cross-sectional fashion. Total iron (β (95% confidence interval) = -0.19 (-0.35, -0.05); p = 0.01 in the most adjusted model) and non-haem iron (β (95% confidence interval) = -0.19 (-0.33, -0.04); p = 0.03 in the most adjusted model) were significantly associated with FPG, consistently in all adjusted model. Total iron and non-haem iron did not have consistent significant associations with HbA1c. Dietary haem iron intake was not associated with either FPG or HbA1c. Habitual intake of dietary iron is inversely associated with FPG in individuals after an attack of AP and may be involved in the pathogenesis of new-onset diabetes after pancreatitis. Prospective longitudinal studies are now warranted to unveil the specific mechanism underlying the involvement of dietary iron.