Serum free fatty acid concentration in patients with acute pancreatitis

Toll-like receptor 4 in pancreatic damage and immune infiltration in acute pancreatitis

Acute pancreatitis is a complex inflammatory disease resulting in extreme pain and can result in significant morbidity and mortality. It can be caused by several factors ranging from genetics, alcohol use, gall stones, and ductal obstruction caused by calcification or neutrophil extracellular traps. Acute pancreatitis is also characterized by immune cell infiltration of neutrophils and M1 macrophages. Toll-like receptor 4 (TLR4) is a pattern recognition receptor that has been noted to respond to endogenous ligands such as high mobility group box 1 (HMGB1) protein and or exogenous ligands such as lipopolysaccharide both of which can be present during the progression of acute pancreatitis. This receptor can be found on a variety of cell types from endothelial cells to resident and infiltrating immune cells leading to production of pro-inflammatory cytokines as well as immune cell activation and maturation resulting in the furthering of pancreatic damage during acute pancreatitis. In this review we will address the various mechanisms mediated by TLR4 in the advancement of acute pancreatitis and how targeting this receptor could lead to improved outcomes for patients suffering from this condition.

A single-center experience of non-bioartificial DFAPP support systems among Chinese patients with hyperlipidemic moderate/severe acute pancreatitis

To assess the clinical efficacy of Double Filtration Plasmapheresis (DFAPP), a novel blood purification method, in treating hyperlipidemic moderate/severe pancreatitis (HL-M/SAP). A total of 68 HL-M/SAP patients were enrolled in this study. The observation group, comprising 34 patients, received DFAPP treatment, while the control group underwent CVVH + PA treatment. We compared the efficacy changes between the two groups post-treatment. Patients treated with DFAPP showed significant improvements in clinical outcomes. After 72 h of DFAPP treatment, HL-M/SAP patients exhibited notably lower multiple organ failure scores and a reduced mortality rate compared to those in the CVVH + PA group. Triglyceride levels in HL-M/SAP patients treated with DFAPP for 48 h averaged 3.75 ± 1.95, significantly lower than the 9.57 ± 3.84 levels in the CVVH + PA group (P < 0.05). Moreover, CRP levels decreased markedly, IL-17 levels diminished, IL-10 levels increased, and the decline in IL-35 levels was significantly less pronounced compared to the CVVH + PA group. The recurrence rate of pancreatitis was also significantly lower after 6 months. The early implementation of DFAPP in HL-M/SAP patients effectively reduces triglyceride levels, suppresses pro-inflammatory factors, enhances anti-inflammatory factors, and mitigates cytokine storm-induced sepsis damage. Consequently, this leads to a decrease in the incidence of multiple organ failure, improved patient survival rates, and a reduce the recurrence rate of lipogenic pancreatitis.Trial registration: Chinese Clinical Trial Registry, ChiCTR2300076066.

Comparative transcriptomic analysis of mammary gland tissues reveals the critical role of GPR110 in palmitic acid-stimulated milk protein and fat synthesis

The G protein-coupled receptors (GPCR) sensing nutritional signals (amino acids, fatty acids, glucose, etc.) are not fully understood. In this research, we used transcriptome sequencing to analyse differentially expressed genes (DEG) in mouse mammary gland tissues at puberty, lactation and involution stages, in which eight GPCR were selected out and verified by qRT-PCR assay. It was further identified the role of GPR110-mediating nutrients including palmitic acid (PA) and methionine (Met) to improve milk synthesis using mouse mammary epithelial cell line HC11. PA but not Met affected GPR110 expression in a dose-dependent manner. GPR110 knockdown decreased milk protein and fat synthesis and cell proliferation and blocked the stimulation of PA on mechanistic target of rapamycin (mTOR) phosphorylation and sterol-regulatory element binding protein 1c (SREBP-1c) expression. In summary, these experimental results disclose DEG related to lactation and reveal that GPR110 mediates PA to activate the mTOR and SREBP-1c pathways to promote milk protein and fat synthesis.

Relationship of circulating levels of long-chain fatty acids to persistent organ failure in acute pancreatitis

During acute pancreatitis (AP), free fatty acids (FFAs) are liberated from circulating triglycerides (TG) and injured adipocytes by pancreatic lipase. Circulating FFAs have been suspected as a source of systemic lipotoxicity in AP. However, assessment of FFAs is difficult and time-consuming, and little is known about relative levels of FFAs between patients with different severities of AP and controls. This study's aims were to assess early circulating levels of FFAs, (both saturated and unsaturated) in patients with AP vs. controls, and associations between FFA levels and AP severity. Serum samples from patients with AP were collected at enrollment (day 1 of hospital stay); serum samples were also collected from controls. FFAs including palmitic, palmitoleic, stearic, oleic, and linoleic acid were extracted and quantitated using gas chromatography separation. Severity of AP was determined by Revised Atlanta Classification. Differences in FFA levels and percentages of total FFAs were assessed between patients with AP and controls and patients with AP of different severity grades. A total of 93 patients with AP (48 female, 52%) and 29 controls (20 female, 69%) were enrolled. Of the patients with AP, 74 had mild/moderate and 19 had severe AP. Serum levels of all FFAs except stearic acid were significantly higher in patients with AP compared with controls. A strong and independent association between elevated palmitoleic acid levels and severe AP was found. Serum unsaturated FFA levels, specifically palmitoleic acid, appear to correlate with severe AP. These findings have potential clinical implications for targeted AP therapies.NEW & NOTEWORTHY Drivers of the inflammatory response in acute pancreatitis remain incompletely understood. Unsaturated fatty acids, specifically palmitoleic, appear to have an association with more severe acute pancreatitis. This finding presents a new clinical understanding of fatty acid toxicity and highlights a potential future target for treatment in severe acute pancreatitis.

Oleic Acid Dissolves cGAS-DNA Phase Separation to Inhibit Immune Surveillance

Phase separation (PS) is a fundamental principle in diverse life processes including immunosurveillance. Despite numerous studies on PS, little is known about its dissolution. Here, it is shown that oleic acid (OA) dissolves the cyclic GMP-AMP synthase (cGAS)-deoxyribonucleic acid (DNA) PS and inhibits immune surveillance of DNA. As solvent components control PS and metabolites are abundant cellular components, it is speculated that some metabolite(s) may dissolve PS. Metabolite-screening reveals that the cGAS-DNA condensates formed via PS are markedly dissolved by long-chain fatty acids, including OA. OA revokes intracellular cGAS-PS and DNA-induced activation. OA attenuates cGAS-mediated antiviral and anticancer immunosurveillance. These results link metabolism and immunity by dissolving PS, which may be targeted for therapeutic interventions.

Mechanisms linking hypertriglyceridemia to acute pancreatitis

Hypertriglyceridemia (HTG) is a metabolic disorder, defined when serum or plasma triglyceride concentration (seTG) is >1.7 mM. HTG can be categorized as mild to very severe groups based on the seTG value. The risk of acute pancreatitis (AP), a serious disease with high mortality and without specific therapy, increases with the degree of HTG. Furthermore, even mild or moderate HTG aggravates AP initiated by other important etiological factors, including alcohol or bile stone. This review briefly summarizes the pathophysiology of HTG, the epidemiology of HTG-induced AP and the clinically observed effects of HTG on the outcomes of AP. Our main focus is to discuss the pathophysiological mechanisms linking HTG to AP. HTG is accompanied by an increased serum fatty acid (FA) concentration, and experimental results have demonstrated that these FAs have the most prominent role in causing the consequences of HTG during AP. FAs inhibit mitochondrial complexes in pancreatic acinar cells, induce pathological elevation of intracellular Ca²⁺ concentration, cytokine release and tissue injury, and reduce the function of pancreatic ducts. Furthermore, high FA concentrations can induce respiratory, kidney, and cardiovascular failure in AP. All these effects may contribute to the observed increased AP severity and frequent organ failure in patients. Importantly, experimental results suggest that the reduction of FA production by lipase inhibitors can open up new therapeutic options of AP. Overall, investigating the pathophysiology of HTG-induced AP or AP in the presence of HTG and determining possible treatments are needed.

Fire in the belly: A scoping review of the immunopathological mechanisms of acute pancreatitis

Introduction

Acute pancreatitis (AP) is characterised by an inflammatory response that in its most severe form can cause a systemic dysregulated immune response and progression to acute multi-organ dysfunction. The pathobiology of the disease is unclear and as a result no targeted, disease-modifying therapies exist. We performed a scoping review of data pertaining to the human immunology of AP to summarise the current field and to identify future research opportunities.

Methods

A scoping review of all clinical studies of AP immunology was performed across multiple databases. Studies were included if they were human studies of AP with an immunological outcome or intervention.

Results

205 studies met the inclusion criteria for the review. Severe AP is characterised by significant immune dysregulation compared to the milder form of the disease. Broadly, this immune dysfunction was categorised into: innate immune responses (including profound release of damage-associated molecular patterns and heightened activity of pattern recognition receptors), cytokine profile dysregulation (particularly IL-1, 6, 10 and TNF-α), lymphocyte abnormalities, paradoxical immunosuppression (including HLA-DR suppression and increased co-inhibitory molecule expression), and failure of the intestinal barrier function. Studies including interventions were also included. Several limitations in the existing literature have been identified; consolidation and consistency across studies is required if progress is to be made in our understanding of this disease.

Conclusions

AP, particularly the more severe spectrum of the disease, is characterised by a multifaceted immune response that drives tissue injury and contributes to the associated morbidity and mortality. Significant work is required to develop our understanding of the immunopathology of this disease if disease-modifying therapies are to be established.

Evidence showing lipotoxicity worsens outcomes in covid-19 patients and insights about the underlying mechanisms

We compared three hospitalized patient cohorts and conducted mechanistic studies to determine if lipotoxicity worsens COVID-19. Cohort-1 (n = 30) compared COVID-19 patients dismissed home to those requiring intensive-care unit (ICU) transfer. Cohort-2 (n = 116) compared critically ill ICU patients with and without COVID-19. Cohort-3 (n = 3969) studied hypoalbuminemia and hypocalcemia’s impact on COVID-19 mortality. Patients requiring ICU transfer had higher serum albumin unbound linoleic acid (LA). Unbound fatty acids and LA were elevated in ICU transfers, COVID-19 ICU patients and ICU non-survivors. COVID-19 ICU patients (cohort-2) had greater serum lipase, damage-associated molecular patterns (DAMPs), cytokines, hypocalcemia, hypoalbuminemia, organ failure and thrombotic events. Hypocalcemia and hypoalbuminemia independently associated with COVID-19 mortality in cohort-3. Experimentally, LA reacted with albumin, calcium and induced hypocalcemia, hypoalbuminemia in mice. Endothelial cells took up unbound LA, which depolarized their mitochondria. In mice, unbound LA increased DAMPs, cytokines, causing endothelial injury, organ failure and thrombosis. Therefore, excessive unbound LA in the circulation may worsen COVID-19 outcomes.

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Three cohorts of hospitalized COVID-19 patients with different severities were studied

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Severe COVID-19 increased serum linoleic acid (LA) and unbound fatty acid levels

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Endothelial cell uptake of unbound LA dose-dependently depolarized mitochondria

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Unbound LA increased cytokines, endothelial injury, organ failure and thrombosis

Pathologic mechanism of hidden blood loss after total knee arthroplasty: oxidative stress induced by free fatty acids

BACKGROUND

Hidden blood loss (HBL) often occurs after joint replacement; however, the mechanism of HBL is not clear. We conducted a prospective study to analyze the correlation between high-level free fatty acids (FFA) and erythrocyte injury, and explore the pathologic mechanism of hidden blood loss (HBL) after total knee arthroplasty (TKA).

METHODS

Perioperative blood indexes were tested in 120 patients who underwent unilateral total knee replacement for end-stage knee osteoarthritis. The changes in FFA, reactive oxygen species (ROS), hemoglobin (Hb), and red blood cells (RBC) in the blood samples were detected. The activity of glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD) and hydrogen peroxide (H₂O₂) levels were measured. Morphologic changes of blood cells were analyzed under a microscope.

RESULTS

HBL occurred in all patients after TKA. The Hb and RBC decreased significantly 24 h after surgery (P <0.05), while FFA and ROS concentration were substantially elevated, and heteromorphic red blood cells appeared under the microscope. The hemoglobin content decreased to its lowest level at 48 h after the operation (P<0.01). With the increase of FFA and ROS levels, HBL appeared more obvious (P<0.01). GSH-PX activity, T-SOD activity, and H₂O₂ levels significantly decreased compared to preoperative tested samples (P<0.01). Microscopically, atypical erythrocytes increased significantly with cellular rupture and lysis identified.

CONCLUSIONS

High levels of FFA in blood can induce oxidative stress and damage red blood cells, leading to the occurrence of HBL after surgery.

TRIAL REGISTRATION

Chinese Clinical Trials Registry (the trial number: ChiCTR17010681, URL: http://www.chictr.org.cn).

Comparable Triglyceride Reduction With Plasma Exchange and Insulin in Acute Pancreatitis - A Randomized Trial

Background and Aims

Both insulin and plasma exchange (PE) are used in hypertriglyceridemic acute pancreatitis (HTG-AP). Our aim was to compare the efficacy of both treatments.

Methods

A randomized, parallel group study performed in a tertiary hospital in 22 HTG-AP patients with non-severe prognosis and triglycerides between 15 and 40 mmol/L. Patients were randomized to daily PE or insulin infusion until triglycerides were <10 mmol/L. Primary outcome was % reduction in triglycerides within 24 h. Secondary outcomes were days needed to lower triglycerides <10 mmol/L, highest CRP and percentage of patients with a severe course of pancreatitis.

Results

There was a trend toward a greater decrease in triglycerides within the first 24 h in the PE group (67 ± 17% vs. 53 ± 17%, p = 0.07), but the absolute difference was modest [mean difference of 6 mmol/L (14% of initial value)]. Triglycerides fell below 10 mmol/L in a median (IQR) of 1 (1-2) and 2 (1-2) days, respectively (p = 0.25). Secondary outcomes related to disease severity were also comparable: highest CRP 229 vs. 211 mg/L (p = 0.69) and severe course of pancreatitis in 2/11 cases in both groups (p = 1.0). Regarding treatment complications, there was one mild hypoglycemia and one allergic reaction during PE. Survival was 100% in both groups.

Conclusion

There was no significant difference, but only a trend toward a greater decrease in triglycerides with PE, and the clinical course was also comparable. These results do not support universal use of PE in patients with HTG-AP.

Clinical Trial Registration

[ClinicalTrials.gov], identifier [NCT02622854].

Pathophysiology and Biomarker Potential of Fatty Acid Ethyl Ester Elevation During Alcoholic Pancreatitis

BACKGROUND & AIMS

The role of fatty acid ethyl esters (FAEEs) during human alcoholic pancreatitis is unknown. We compared FAEEs levels with their nonesterified fatty acids (NEFAs) precursors during alcohol intoxication and clinical alcoholic pancreatitis. The pathophysiology underlying FAEEs increase and their role as diagnostic biomarkers for alcoholic pancreatitis was investigated.

METHODS

A prospective blinded study compared FAEEs, NEFAs, and ethanol blood levels on hospitalization for alcoholic pancreatitis (n = 31), alcohol intoxication (n = 25), and in normal controls (n = 43). Serum FAEEs were measured at admission for nonalcoholic pancreatitis (n = 75). Mechanistic cell and animal studies were done.

RESULTS

Median FAEEs were similarly elevated during alcohol intoxication (205 nmol/L; 95% confidence interval [CI], 71.8-515 nmol/L, P < .001) and alcoholic pancreatitis (103.1 nmol/L; 95% CI, 53-689 nmol/L, P < .001) vs controls (1.7 nmol/L; 95% CI, 0.02-4.3 nmol/L) or nonalcoholic pancreatitis (8 nmol/L; 95% CI, 1.1-11.5 nmol/L). Alcoholic pancreatitis increased serum NEFAs (1024 ± 710 μmol/L vs 307 ± 185 μmol/L in controls, P < .05). FAEEs comprised 0.1% to 2% of the parent NEFA concentrations. FAEES correlated strongly with NEFAs independent of ethanol levels in alcoholic pancreatitis but not during alcohol intoxication. On receiver operating characteristic curve analysis for diagnosing alcoholic pancreatitis, the area under the curve for serum FAEEs was 0.87 (95% CI, 0.78-0.95, P < .001). In mice and cells, alcohol administration transiently increased all FAEEs. Oleic acid ethyl ester was the only FAEE with a sustained increase up to 24 hours after intraperitoneal oleic acid plus ethanol administration.

CONCLUSIONS

The sustained, alcohol-independent, large (20- to 50-fold) increase in circulating FAEEs during alcoholic pancreatitis results from their visceral release and mirrors the 2- to 4-fold increase in parent NEFA. The large areas under the curve of FAEEs on receiver operating characteristic curve analysis supports their role as alcoholic pancreatitis biomarkers.

Metabolomic-based clinical studies and murine models for acute pancreatitis disease: A review

Acute pancreatitis (AP) is one of the most common gastroenterological disorders requiring hospitalization and is associated with substantial morbidity and mortality. Metabolomics nowadays not only help us to understand cellular metabolism to a degree that was not previously obtainable, but also to reveal the importance of the metabolites in physiological control, disease onset and development. An in-depth understanding of metabolic phenotyping would be therefore crucial for accurate diagnosis, prognosis and precise treatment of AP. In this review, we summarized and addressed the metabolomics design and workflow in AP studies, as well as the results and analysis of the in-depth of research. Based on the metabolic profiling work in both clinical populations and experimental AP models, we described the metabolites with potential utility as biomarkers and the correlation between the altered metabolites and AP status. Moreover, the disturbed metabolic pathways correlated with biological function were discussed in the end. A practical understanding of current and emerging metabolomic approaches applicable to AP and use of the metabolite information presented will aid in designing robust metabolomics and biological experiments that result in identification of unique biomarkers and mechanisms, and ultimately enhanced clinical decision-making.

The relationship of oleic acid/albumin molar ratio and clinical outcomes in leptospirosis

Human leptospirosis is an acute infectious zoonosis presenting specific lipid disorders. Previous in vitro studies showed both leptospira glycolipoprotein endotoxin, and high oleic acid levels were associated with Na/K-ATPase inhibition that is amplified by the reduction of circulating albumin levels. In this study, we aimed to investigate the relationship of oleic acid/albumin (OA/A) molar ratio and clinical outcomes in Leptospirosis. Through a prospective observational cohort study employing high-performance liquid chromatography (HPLC) we sequentially determined serum concentrations of nonesterified fatty acids (NEFA) and albumin in twenty-eight patients with severe leptospirosis since their hospital admission. Twenty patients recovered, and eight died. Data was distributed in two groups according to clinical outcomes. Oleic acid/albumin molar ratios (OA/A), initial samples, were higher than those in healthy donors. The ratio OA/A, however, persisted high in dying patients, whereas patients who survived had a reduction matching to healthy donors. Biochemical alterations suggest that cure is correlated to the reestablishment of the OA/A molar ratio, while fatal outcomes related to persisting OA/A imbalances. Analysis by receiver operating characteristic (ROC) showed the area under the curve of 0.864 and the cutoff value of 0.715 being associated with a high odds ratio. Lipid analysis from patients with leptospirosis had an acute high serum OA/A molar ratio, and sustained imbalance has a high odds ratio and strong correlation with mortality.

Pancreatic triglyceride lipase mediates lipotoxic systemic inflammation

Visceral adipose tissue plays a critical role in numerous diseases. Although imaging studies often show adipose involvement in abdominal diseases, their outcomes may vary from being a mild self-limited illness to one with systemic inflammation and organ failure. We therefore compared the pattern of visceral adipose injury during acute pancreatitis and acute diverticulitis to determine its role in organ failure. Acute pancreatitis-associated adipose tissue had ongoing lipolysis in the absence of adipocyte triglyceride lipase (ATGL). Pancreatic lipase injected into mouse visceral adipose tissue hydrolyzed adipose triglyceride and generated excess nonesterified fatty acids (NEFAs), which caused organ failure in the absence of acute pancreatitis. Pancreatic triglyceride lipase (PNLIP) increased in adipose tissue during pancreatitis and entered adipocytes by multiple mechanisms, hydrolyzing adipose triglyceride and generating excess NEFAs. During pancreatitis, obese PNLIP-knockout mice, unlike obese adipocyte-specific ATGL knockouts, had lower visceral adipose tissue lipolysis, milder inflammation, less severe organ failure, and improved survival. PNLIP-knockout mice, unlike ATGL knockouts, were protected from adipocyte-induced pancreatic acinar injury without affecting NEFA signaling or acute pancreatitis induction. Therefore, during pancreatitis, unlike diverticulitis, PNLIP leaking into visceral adipose tissue can cause excessive visceral adipose tissue lipolysis independently of adipocyte-autonomous ATGL, and thereby worsen organ failure.

Experimental Acute Pancreatitis Models: History, Current Status, and Role in Translational Research

Acute pancreatitis is a potentially severe inflammatory disease that may be associated with a substantial morbidity and mortality. Currently there is no specific treatment for the disease, which indicates an ongoing demand for research into its pathogenesis and development of new therapeutic strategies. Due to the unpredictable course of acute pancreatitis and relatively concealed anatomical site in the retro-peritoneum, research on the human pancreas remains challenging. As a result, for over the last 100 years studies on the pathogenesis of this disease have heavily relied on animal models. This review aims to summarize different animal models of acute pancreatitis from the past to present and discuss their main characteristics and applications. It identifies key studies that have enhanced our current understanding of the pathogenesis of acute pancreatitis and highlights the instrumental role of animal models in translational research for developing novel therapies.

Ringer's Lactate Prevents Early Organ Failure by Providing Extracellular Calcium

OBJECTIVE

Ringer's lactate may improve early systemic inflammation during critical illnesses like severe acute pancreatitis, which are associated with hypocalcemia. Ringer's lactate is buffered and contains lactate and calcium. We, thus analyzed extracellular calcium or lactate's effects on the mechanisms, intermediary markers, and organ failure in models mimicking human disease with nonesterified fatty acid (NEFA) elevation.

METHODS

Meta-analyses and experimental studies were performed. Experimentally, extracellular calcium and lactate were compared in their interaction with linoleic acid (LA; a NEFA increased in human severe pancreatitis), and its subsequent effects on mitochondrial depolarization and cytosolic calcium signaling resulting in cell injury. In vivo, the effect of LA was studied on organ failure, along with the effect of calcium or lactate (pH 7.4) on severe acute pancreatitis-associated organ failure. A meta-analysis of human randomized control trials comparing Ringer's lactate to normal saline was done, focusing on necrosis and organ failure.

RESULTS

Calcium reacted ionically with LA and reduced lipotoxic necrosis. In vivo, LA induced organ failure and hypocalcemia. During severe pancreatitis, calcium supplementation in saline pH 7.4, unlike lactate, prevented hypocalcemia, increased NEFA saponification, reduced circulating NEFA and C-reactive protein , reduced pancreatic necrosis adjacent to fat necrosis, and normalized shock (carotid pulse distension) and blood urea nitrogen elevation on day 1. This, however, did not prevent the later increase in serum NEFA which caused delayed organ failure. Meta-analysis showed Ringer's lactate reduced necrosis, but not organ failure, compared with normal saline.

CONCLUSION

Hypocalcemia occurs due to excess NEFA binding calcium during a critical illness. Ringer's lactate's early benefits in systemic inflammation are by the calcium it provides reacting ionically with NEFA. This, however, does not prevent later organ failure from sustained NEFA generation. Future studies comparing calcium supplemented saline resuscitation to Ringer's lactate may provide insights to this pathophysiology.

GC-MS based metabolomics strategy to distinguish three types of acute pancreatitis

Acute pancreatitis (AP) is a progressive systemic inflammatory response with high morbidity and high mortality, which is mainly caused by alcohol, bulimia, gallstones and hyperlipidemia. The early diagnosis of different types of AP and further explore potential pathophysiological mechanism of each type of AP is beneficial for optimized treatment strategies and better patient's care. In this study, a metabolomics approach based on gas chromatography-mass spectrometry (GC-MS), and random forests algorithm was established to distinguish biliary acute pancreatitis (BAP), Hyperlipidemia acute pancreatitis (HLAP), and alcoholic acute pancreatitis (AAP), from healthy controls. The classification accuracies for BAP, HLAP, and AAP patients compared with healthy control, were 0.886, 0.906 and 0.857, respectively, by using 5-fold cross-validation method. And some special metabolites for each type of AP were discovered, such as l-Lactic acid, (R)-3-Hydroxybutyric acid, Phosphoric acid, Glycine, Erythronic acid, l-Phenylalanine, d-Galactose, l-Tyrosine, Arachidonic acid, Glycerol 1-hexadecanoate. Furthermore, associations between these metabolites with the metabolism of amino acids, fatty acids were identified. Our studies have illuminated the biomarkers and physiological mechanism of disease in a clinical setting, which suggested that metabolomics is a valuable tool for identifying the molecular mechanisms that are involved in the etiology of BAP, AAP, HLAP and thus novel therapeutic targets.

A prospective pilot study using metabolomics discloses specific fatty acid, catecholamine and tryptophan metabolic pathways as possible predictors for a negative outcome after severe trauma

Background

We wanted to define metabolomic patterns in plasma to predict a negative outcome in severe trauma patients.

Methods

A prospective pilot study was designed to evaluate plasma metabolomic patterns, established by liquid chromatography coupled to mass spectrometry, in patients allocated to an intensive care unit (in the University Hospital Arnau de Vilanova, Lleida, Spain) in the first hours after a severe trauma (n = 48). Univariate and multivariate statistics were employed to establish potential predictors of mortality.

Results

Plasma of patients non surviving to trauma (n = 5) exhibited a discriminating metabolomic pattern, involving basically metabolites belonging to fatty acid and catecholamine synthesis as well as tryptophan degradation pathways. Thus, concentration of several metabolites exhibited an area under the receiver operating curve (ROC) higher than 0.84, including 3-indolelactic acid, hydroxyisovaleric acid, phenylethanolamine, cortisol, epinephrine and myristic acid. Multivariate binary regression logistic revealed that patients with higher myristic acid concentrations had a non-survival odds ratio of 2.1 (CI 95% 1.1–3.9).

Conclusions

Specific fatty acids, catecholamine synthesis and tryptophan degradation pathways could be implicated in a negative outcome after trauma. The metabolomic study of severe trauma patients could be helpful for biomarker proposal.

Electronic supplementary material

The online version of this article (10.1186/s13049-019-0631-5) contains supplementary material, which is available to authorized users.

Oleic acid ameliorates palmitic acid-induced ER stress and inflammation markers in naive and cerulein-treated exocrine pancreas cells

Dietary fat overload (typical to obesity) increases the risk of pancreatic pathologies through mechanisms yet to be defined. We previously showed that saturated dietary fat induces pancreatic acinar lipotoxicity and cellular stress. The endoplasmic reticulum (ER) of exocrine pancreas cells is highly developed and thus predisposed to stress. We studied the combination of saturated and unsaturated FAs in metabolic and pancreatitis like cerulein (CER)-induced stress states on cellular ER stress.

Exocrine pancreas AR42J and rat primary exocrine acinar cells underwent acute (24 h) challenge with different FAs (saturated, monounsaturated) at different concentrations (250 and 500 µM) and in combination with acute CER-induced stress, and were analyzed for fat accumulation, ER stress unfolded protein response (UPR) and immune and enzyme markers. Acute exposure of AR42J and pancreatic acinar cells to different FAs and their combinations increased triglyceride accumulation. Palmitic acid significantly dose-dependently enhanced the UPR, immune factors and pancreatic lipase (PL) levels, as demonstrated by XBP1 splicing and elevation in UPR transcripts and protein levels (Xbp1,Atf6, Atf4, Chop, Tnfα, Tgfβ and Il-6). Exposure to high palmitic levels in a CER-induced stress state synergistically increased ER stress and inflammation marker levels. Exposure to oleic acid did not induce ER stress and PL levels and significantly decreased immune factors in an acute CER-induced stress state. Combination of oleic and palmitic acids significantly reduced the palmitic-induced ER stress, but did not affect the immune factor response. We show that combination of monounsaturated and saturated FAs protects from exocrine pancreatic cellular ER stress in both metabolic and CER-induced stress.

Organ Failure Due to Systemic Injury in Acute Pancreatitis

Acute pancreatitis may be associated with both local and systemic complications. Systemic injury manifests in the form of organ failure, which is seen in approximately 20% of all cases of acute pancreatitis and defines "severe acute pancreatitis." Organ failure typically develops early in the course of acute pancreatitis, but also may develop later due to infected pancreatic necrosis-induced sepsis. Organ failure is the most important determinant of outcome in acute pancreatitis. We review here the current understanding of the risk factors, pathophysiology, timing, impact on outcome, and therapy of organ failure in acute pancreatitis. As we discuss the pathophysiology of severe systemic injury, the distinctions between markers and mediators of severity are highlighted based on evidence supporting their causality in organ failure. Emphasis is placed on clinically relevant end points of organ failure and the mechanisms underlying the pathophysiological perturbations, which offer insight into potential therapeutic targets to treat.

Association of the hypertriglyceridemic waist phenotype and severity of acute pancreatitis

Background

The aim of this study was to evaluate the effect of a simple visceral obesity phenotype, known as the hypertriglyceridemic waist phenotype and its quantitative indicator waist circumference index on the severity of acute pancreatitis.

Materials and methods

Diagnosis and severity analysis of acute pancreatitis were determined according to the Atlanta classification guidelines, revised in 2012. We considered the hypertriglyceridemic waist phenotype as characterized by increased waist circumference and elevated triglyceride concentrations. We investigated the association between the acute pancreatitis severity and hypertriglyceridemic waist phenotype, including waist circumference index.

Results

The hypertriglyceridemic waist phenotype was significantly associated with systemic inflammatory response syndrome, organ failure, and severe acute pancreatitis. The median waist circumference index and demonstration of hypertriglyceridemic waist phenotype were positively correlated with acute pancreatitis severity. In addition, multivariate logistic analysis showed that patients with the hypertriglyceridemic waist phenotype had 1.664 times the risk of organ failure and 1.891 times the risk of systemic inflammatory response syndrome, compared with the other groups.

Conclusion

Upon admission, the hypertriglyceridemic waist phenotype was strongly associated with acute pancreatitis in patients. This phenotype, including waist circumference index, might be a simple method for evaluating individuals at high risk of severe acute pancreatitis.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-1019-2) contains supplementary material, which is available to authorized users.

Carboxyl Ester Lipase May Not Mediate Lipotoxic Injury during Severe Acute Pancreatitis

Acute lipolysis of visceral fat or circulating triglycerides may worsen acute pancreatitis (AP)-associated local and systemic injury. The pancreas expresses pancreatic triacylglycerol lipase (PNLIP), pancreatic lipase-related protein 2 (PNLIPRP2), and carboxyl ester lipase (CEL), which may leak into the visceral fat or systemic circulation during pancreatitis. We, thus, aimed to determine the pancreatic lipase(s) regulating lipotoxicity during AP. For this AP, associated fat necrosis was analyzed using Western blot analysis. Bile acid (using liquid chromatography-tandem mass spectrometry) and fatty acid (using gas chromatography) concentrations were measured in human fat necrosis. The fat necrosis milieu was simulated in vitro using glyceryl trilinoleate because linoleic acid is increased in fat necrosis. Bile acid requirements to effectively hydrolyze glyceryl trilinoleate were studied using exogenous or overexpressed lipases. The renal cell line (HEK 293) was used to study lipotoxic injury. Because dual pancreatic lipase knockouts are lethal, exocrine parotid acini lacking lipases were used to verify the results. PNLIP, PNLIPRP2, and CEL were increased in fat necrosis. Although PNLIP and PNLIPRP2 were equipotent in inducing lipolysis and lipotoxic injury, CEL required bile acid concentrations higher than in human fat necrosis. The high bile acid requirements for effective lipolysis make CEL an unlikely mediator of lipotoxic injury in AP. It remains to be explored whether PNLIP or PNLIPRP2 worsens AP severity in vivo.

Effect of Sheng-jiang powder on multiple-organ inflammatory injury in acute pancreatitis in rats fed a high-fat diet

BACKGROUND

Obesity worsens inflammatory organ injury in acute pancreatitis (AP), but there is no effective preventive strategy. Sheng-jiang powder (SJP) has been shown to alleviate multiple-organ inflammatory injury in rats with high-fat diet-induced obesity. Hence, SJP is supposed to have an effect on multiple-organ inflammatory injury in AP in rats fed a high-fat diet.

AIM

To explore how obesity may contribute to aggravating inflammatory organ injury in AP in rats and observe the effect of SJP on multiple-organ inflammatory injury in AP in rats fed a high-fat diet.

METHODS

Rats were randomly assigned to a control group (CG), an obese group (OG), and an SJP treatment group (SG), with eight rats per group. The rats in the OG and SG were fed a high-fat diet. From the third week, the rats in the SG were given oral doses of SJP (5 g/kg of body weight). After 12 wk, AP was induced in the three groups. Serum amylase level, body weight, Lee’s index, serum biochemistry parameters, and serum inflammatory cytokine and tissue cytokine levels were assessed, and the tissue histopathological scores were evaluated and compared.

RESULTS

Compared with the CG, serum triglyceride, total cholesterol, interleukin-6, and interleukin-10 levels were significantly higher in the OG, and serum high-density lipoprotein cholesterol level was significantly lower in the OG. Moreover, enhanced oxidative damage was observed in the pancreas, heart, spleen, lung, intestine, liver, and kidney. Evidence of an imbalanced antioxidant defense system, especially in the pancreas, spleen, and intestine, was observed in the obese AP rats. Compared with the OG, serum high-density lipoprotein cholesterol, interleukin-10, and superoxide dismutase expression levels in the pancreas, spleen, and intestine were increased in the SG. Additionally, SJP intervention led to a decrease in the following parameters: body weight; Lee’s index; serum triglyceride levels; serum total cholesterol levels; malondialdehyde expression levels in the pancreas, heart, spleen, lung, and liver; myeloperoxidase expression levels in the lung; and pathological scores in the liver.

CONCLUSION

Obesity may aggravate the inflammatory reaction and pathological multiple-organ injury in AP rats, and SJP may alleviate multiple-organ inflammatory injury in AP in rats fed a high-fat diet.

Free Fatty Acids' Level and Nutrition in Critically Ill Patients and Association with Outcomes: A Prospective Sub-Study of PermiT Trial

OBJECTIVES

The objectives of this study were to evaluate the clinical and nutritional correlates of high free fatty acids (FFAs) level in critically ill patients and the association with outcomes, and to study the effect of short-term caloric restriction (permissive underfeeding) on FFAs level during critical illness.

PATIENTS/METHOD

In this pre-planned sub-study of the PermiT (Permissive Underfeeding vs. Target Enteral Feeding in Adult Critically Ill Patients) trial, we included critically ill patients who were expected to stay for ≥14 days in the intensive care unit. We measured FFAs level on day 1, 3, 5, 7, and 14 of enrollment. Of 70 enrolled patients, 23 (32.8%) patients had high FFAs level (baseline FFAs level >0.45 mmol/L in females and >0.6 mmol/L in males).

RESULTS

Patients with high FFAs level were significantly older and more likely to be females and diabetics and they had lower ratio of partial pressure of oxygen to the fraction of inspired oxygen, higher creatinine, and higher total cholesterol levels than those with normal FFAs level. During the study period, patients with high FFAs level had higher blood glucose and required more insulin. On multivariable logistic regression analysis, the predictors of high baseline FFAs level were diabetes (adjusted odds ratio (aOR): 5.36; 95% confidence interval (CI): 1.56, 18.43, p = 0.008) and baseline cholesterol level (aOR, 4.29; 95% CI: 11.64, 11.19, p = 0.003). Serial levels of FFAs did not differ with time between permissive underfeeding and standard feeding groups. FFAs level was not associated with 90-day mortality (aOR: 0.49; 95% CI: 0.09, 2.60, p = 0.40).

CONCLUSION

We conclude that high FFAs level in critically ill patients is associated with features of metabolic syndrome and is not affected by short-term permissive underfeeding.

Multimodal Transgastric Local Pancreatic Hypothermia Reduces Severity of Acute Pancreatitis in Rats and Increases Survival

BACKGROUND & AIMS

Acute pancreatitis (AP) of different etiologies is associated with the activation of different signaling pathways in pancreatic cells, posing challenges to the development of targeted therapies. We investigated whether local pancreatic hypothermia, without systemic hypothermia, could lessen the severity of AP induced by different methods in rats.

METHODS

A urethane balloon with 2 polyurethane tubes was placed inside the stomach of rats. AP was induced in Wistar rats by the administration of cerulein or glyceryl tri-linoleate (GTL). Then, cold water was infused into the balloon to cool the pancreas. Pancreatic temperatures were selected based on those found to decrease acinar cell injury. An un-perfused balloon was used as a control. Pancreatic and rectal temperatures were monitored, and an infrared lamp or heating pad was used to avoid generalized hypothermia. We collected blood, pancreas, kidney, and lung tissues and analyzed them by histology, immunofluorescence, immunoblot, cytokine and chemokine magnetic bead, and DNA damage assays. The effect of hypothermia on signaling pathways initiated by cerulein and GTL was studied in acinar cells.

RESULTS

Rats with pancreatic cooling developed less severe GTL-induced AP compared with rats that received the control balloon. In acinar cells, cooling decreased the lipolysis induced by GTL, increased the micellar form of its fatty acid, lowered the increase in cytosolic calcium, prevented the loss of mitochondrial membrane potential (by 70%-80%), and resulted in a 40%-50% decrease in the uptake of a fatty acid tracer. In rats with AP, cooling decreased pancreatic necrosis by 48%, decreased serum levels of cytokines and markers of cell damage, and decreased markers of lung and renal damage. Pancreatic cooling increased the proportions of rats surviving 6 hours after induction of AP (to 90%, from <10% of rats that received the control balloon). In rats with cerulein-induced AP, pancreatic cooling decreased pancreatic markers of apoptosis and inflammation.

CONCLUSIONS

In rats with AP, transgastric local pancreatic hypothermia decreases pancreatic necrosis, apoptosis, inflammation, and markers of pancreatitis severity and increases survival.

Very Severe Hypertriglyceridemia-Casre Report with General Considerations

Hypertriglyceridemia is defined as a value of fasting serum triglyceride over 150 mg/dl. The classification of hypertriglyceridemia according to the Endocrinology Society include mild and moderate hypertriglyceridemia, severe hypertriglyceridemia and very severe hypertriglyceridemia. Mild and moderate hypertriglyceridemia increase the risk for cardiovascular events while severe and very severe hypertriglyceridemia is a risk factor for acute pancreatitis. Conventional pharmacological therapy of hypertriglyceridemia includes: fibrates, niacin, statins, ezetimibe, omega-3-fatty acid. Other triglyceridelowering therapies are represented by plasmapheresis and lipoprotein lipase gene therapy. The present work refers to a 59-year old man without history of family diabetes, dyslipidemia, premature coronary artery disease, diagnosed with T2DM in 2012, from 2014 on insulin treatment; he was hospitalized for endocrine evaluation. History: high blood pressure for approximately 25 years, chronic kidney disease, very severe hypertriglyceridemia, thyroid papillary carcinoma. The patient followed treatment with hypoglycemic, hypolipemic, low salt content diet, fibrates, statins, omega-3-fatty acid. Due to the fact that the patient did not respond to conventional therapy plasmapheresis was considered.

Fingerprinting Acute Digestive Diseases by Untargeted NMR Based Metabolomics

Precision medicine may significantly contribute to rapid disease diagnosis and targeted therapy, but relies on the availability of detailed, subject specific, clinical information. Proton nuclear magnetic resonance (¹H–NMR) spectroscopy of body fluids can extract individual metabolic fingerprints. Herein, we studied 64 patients admitted to the Florence main hospital emergency room with severe abdominal pain. A blood sample was drawn from each patient at admission, and the corresponding sera underwent ¹H–NMR metabolomics fingerprinting. Unsupervised Principal Component Analysis (PCA) analysis showed a significant discrimination between a group of patients with symptoms of upper abdominal pain and a second group consisting of patients with diffuse abdominal/intestinal pain. Prompted by this observation, supervised statistical analysis (Orthogonal Partial Least Squares–Discriminant Analysis (OPLS-DA)) showed a very good discrimination (>90%) between the two groups of symptoms. This is a surprising finding, given that neither of the two symptoms points directly to a specific disease among those studied here. Actually herein, upper abdominal pain may result from either symptomatic gallstones, cholecystitis, or pancreatitis, while diffuse abdominal/intestinal pain may result from either intestinal ischemia, strangulated obstruction, or mechanical obstruction. Although limited by the small number of samples from each of these six conditions, discrimination of these diseases was attempted. In the first symptom group, >70% discrimination accuracy was obtained among symptomatic gallstones, pancreatitis, and cholecystitis, while for the second symptom group >85% classification accuracy was obtained for intestinal ischemia, strangulated obstruction, and mechanical obstruction. No single metabolite stands up as a possible biomarker for any of these diseases, while the contribution of the whole ¹H–NMR serum fingerprint seems to be a promising candidate, to be confirmed on larger cohorts, as a first-line discriminator for these diseases.

The effect of serum triglyceride concentration on the outcome of acute pancreatitis: systematic review and meta-analysis

Elevated serum triglyceride concentration (seTG, >1.7 mM or >150 mg/dL) or in other words hypertriglyceridemia (HTG) is common in the populations of developed countries. This condition is accompanied by an increased risk for various diseases, such as acute pancreatitis (AP). It has been proposed that HTG could also worsen the course of AP. Therefore, in this meta-analysis, we aimed to compare the effects of various seTGs on the severity, mortality, local and systemic complications of AP, and on intensive care unit admission. 16 eligible studies, including 11,965 patients were retrieved from PubMed and Embase. The results showed that HTG significantly elevated the odds ratio (OR = 1.72) for severe AP when compared to patients with normal seTG (<1.7 mM). Furthermore, a significantly higher occurrence of pancreatic necrosis, persistent organ failure and renal failure was observed in groups with HTG. The rates of complications and mortality for AP were significantly increased in patients with seTG >5.6 mM or >11.3 mM versus <5.6 mM or <11.3 mM, respectively. We conclude that the presence of HTG worsens the course and outcome of AP, but we found no significant difference in AP severity based on the extent of HTG.

Fatty Acid Saturation of Albumin Used in Resuscitation Fluids Modulates Cell Damage in Shock: in vitro Results Using a Novel Technique to Measure Fatty Acid Binding Capacity

The use of albumin for resuscitation has not proven as beneficial in human trials as expected from numerous animal studies. One explanation could be the practice of adding fatty acid (FA) during manufacture of pharmaceutical albumin. During ischemia, unbound free FAs (FFA) in the circulation could potentially induce cellular damage. We hypothesized that albumins with higher available binding capacities (ABC) for FFAs may prevent that damage. Therefore, we developed a technique to measure ABC, determined if pharmaceutical human serum albumin (HSA) has decreased ABC compared with FA-free bovine serum albumin (BSA), and if binding capacity would affect hemolysis when blood is mixed with exogenous FFA at levels similar to those observed in shock. The new assay used exogenous oleic acid (OA), glass fiber filtration, and a FFA assay kit. RBC hemolysis was determined by mixing 0 to 5 mM OA with PBS, HSA, FA-free BSA, or FA-saturated BSA and measuring plasma hemoglobin after incubation with human blood. 5% HSA contained 4.7±0.2 mM FFA, leaving an ABC of 5.0 ± 0.6 mM, compared with FA-free BSAs ABC of 7.0 ± 1.3 mM (P < 0.024). Hemolysis after OA was reduced with FA-free BSA but increased with FA-saturated BSA. HSA provided intermediate results. 25% solutions of FA-free BSA and HSA were more protective, while 25% FA-saturated BSA was more damaging than 5% solutions. These findings suggest that increased FA saturation may reverse albumin's potential benefit to lessen cellular damage and may explain, at least in part, its failure in human trauma studies.

Obesity and pancreatitis

PURPOSE OF REVIEW

The obesity pandemic poses a unique set of problems for acute pancreatitis - both by increasing acute pancreatitis incidence, and worsening acute pancreatitis severity. This review explores these associations, underlying mechanisms, and potential therapies.

RECENT FINDINGS

We review how the obesity associated increase in gallstones, surgical, and endoscopic interventions for obesity management, diabetes, and related medications such as incretin-based therapies and hypertriglyceridemia may increase the incidence of acute pancreatitis. The mechanism of how obesity may increase acute pancreatitis severity are discussed with a focus on cytokines, adipokines, damage-associated molecular patterns and unsaturated fatty acid-mediated lipotoxicity. The role of obesity in exacerbating pancreatic necrosis is discussed; focusing on obesity-associated pancreatic steatosis. We also discuss how peripancreatic fat necrosis worsens organ failure independent of pancreatic necrosis. Last, we discuss emerging therapies including choice of intravenous fluids and the use of lipase inhibitors which have shown promise during severe acute pancreatitis.

SUMMARY

We discuss how obesity may contribute to increasing acute pancreatitis incidence, the role of lipolytic unsaturated fatty acid release in worsening acute pancreatitis, and potential approaches, including appropriate fluid management and lipase inhibition in improving acute pancreatitis outcomes.

Outcome benefit of abdominal paracentesis drainage for severe acute pancreatitis patients with serum triglyceride elevation by decreasing serum lipid metabolites

Background

Our previous reports demonstrated that abdominal paracentesis drainage (APD) exerts a beneficial effect on severe acute pancreatitis (SAP) patients. However, the underlying mechanisms for this effectiveness are not well understood.

Methods

A retrospective cohort of 132 consecutive non-hypertriglyceridemia (HTG)-induced SAP patients with triglyceride (TG) elevation and pancreatitis-associated ascitic fluid (PAAF) was recruited from May 2010 to May 2015 and included in this study. The patients were divided into two groups: the APD group (n = 68) and the non-APD group (n = 64). The monitored parameters mainly included mortality, hospital stay, the incidence of further intervention, levels of serum lipid metabolites and inflammatory factors, parameters related to organ failure and infections, and severity scores.

Results

The demographic data and severity scores were comparable between the two groups. Compared with the non-APD group, the primary outcomes (including mortality, hospital stay and the incidence of percutaneous catheter drainage) in the APD group were improved. The serum levels of lipid metabolites were significantly lower in the APD group after 2 weeks of treatment than in the non-APD group. Logistic regression analysis indicated that the decreased extent of free fatty acid (FFA)(odds ratio, 1.435; P = 0.015) was a predictor of clinical improvement after 2 weeks of treatment.

Conclusion

Treatment with APD benefits non-HTG-induced SAP patients with serum TG elevation by decreasing serum levels of FFA.

Omega-9 Oleic Acid Induces Fatty Acid Oxidation and Decreases Organ Dysfunction and Mortality in Experimental Sepsis

Sepsis is characterized by inflammatory and metabolic alterations, which lead to massive cytokine production, oxidative stress and organ dysfunction. In severe systemic inflammatory response syndrome, plasma non-esterified fatty acids (NEFA) are increased. Several NEFA are deleterious to cells, activate Toll-like receptors and inhibit Na⁺/K⁺-ATPase, causing lung injury. A Mediterranean diet rich in olive oil is beneficial. The main component of olive oil is omega-9 oleic acid (OA), a monounsaturated fatty acid (MUFA). We analyzed the effect of OA supplementation on sepsis. OA ameliorated clinical symptoms, increased the survival rate, prevented liver and kidney injury and decreased NEFA plasma levels in mice subjected to cecal ligation and puncture (CLP). OA did not alter food intake and weight gain but diminished reactive oxygen species (ROS) production and NEFA plasma levels. Carnitine palmitoyltransferase IA (CPT1A) mRNA levels were increased, while uncoupling protein 2 (UCP2) liver expression was enhanced in mice treated with OA. OA also inhibited the decrease in 5' AMP-activated protein kinase (AMPK) expression and increased the enzyme expression in the liver of OA-treated mice compared to septic animals. We showed that OA pretreatment decreased NEFA concentration and increased CPT1A and UCP2 and AMPK levels, decreasing ROS production. We suggest that OA has a beneficial role in sepsis by decreasing metabolic dysfunction, supporting the benefits of diets high in monounsaturated fatty acids (MUFA).

Fatty Acid Ethyl Esters Are Less Toxic Than Their Parent Fatty Acids Generated during Acute Pancreatitis

Although ethanol causes acute pancreatitis (AP) and lipolytic fatty acid (FA) generation worsens AP, the contribution of ethanol metabolites of FAs, ie, FA ethyl esters (FAEEs), to AP outcomes is unclear. Previously, pancreata of dying alcoholics and pancreatic necrosis in severe AP, respectively, showed high FAEEs and FAs, with oleic acid (OA) and its ethyl esters being the most abundant. We thus compared the toxicities of FAEEs and their parent FAs in severe AP. Pancreatic acini and peripheral blood mononuclear cells were exposed to FAs or FAEEs in vitro. The triglyceride of OA (i.e., glyceryl tri-oleate) or OAEE was injected into the pancreatic ducts of rats, and local and systemic severities were studied. Unsaturated FAs at equimolar concentrations to FAEEs induced a larger increase in cytosolic calcium, mitochondrial depolarization, and necro-apoptotic cell death. Glyceryl tri-oleate but not OAEE resulted in 70% mortality with increased serum OA, a severe inflammatory response, worse pancreatic necrosis, and multisystem organ failure. Our data show that FAs are more likely to worsen AP than FAEEs. Our observations correlate well with the high pancreatic FAEE concentrations in alcoholics without pancreatitis and high FA concentrations in pancreatic necrosis. Thus, conversion of FAs to FAEE may ameliorate AP in alcoholics.

Serum levels of thyroid hormones and thyroid stimulating hormone in patients with biliogenic and hyperlipidaemic acute pancreatitis: Difference and value in predicting disease severity

Objectives

To compare retrospectively serum levels of thyroid hormones (THs) and thyroid stimulating hormone (TSH) between patients with biliogenic acute pancreatitis (BAP) and those with hyperlipidaemic acute pancreatitis (HLAP), in order to assess their value for predicting the severity of acute pancreatitis (AP).

Methods

Patients with AP were divided into BAP and HLAP groups, then further divided into either a mild AP (MAP) group or a moderately severe AP (MSAP) group. Routine blood parameters were measured. Free tri-iodothyronine (FT3), free thyroxine (FT4) and TSH levels were measured.

Results

Seventy-six patients with AP were enrolled in the study. FT3 and TSH levels were significantly higher in patients with MAP than in patients with MSAP. FT4 and TSH levels were significantly lower in the HLAP group than in the BAP group. TSH levels in both MAP and MSAP patients were significantly lower in the HLAP group than in the BAP group. TSH was inversely correlated with triglyceride levels in patients with HLAP. FT3 was a risk factor for MSAP in patients with AP and also demonstrated moderate accuracy in predicting AP severity.

Conclusions

THs and TSH decrease with the severity of AP, especially in patients with HLAP. FT3 may be a useful biomarker for the early assessment of the severity of AP.

Peripancreatic fat necrosis worsens acute pancreatitis independent of pancreatic necrosis via unsaturated fatty acids increased in human pancreatic necrosis collections

BACKGROUND AND AIMS

Peripancreatic fat necrosis occurs frequently in necrotising pancreatitis. Distinguishing markers from mediators of severe acute pancreatitis (SAP) is important since targeting mediators may improve outcomes. We evaluated potential agents in human pancreatic necrotic collections (NCs), pseudocysts (PCs) and pancreatic cystic neoplasms and used pancreatic acini, peripheral blood mononuclear cells (PBMC) and an acute pancreatitis (AP) model to determine SAP mediators.

METHODS

We measured acinar and PBMC injury induced by agents increased in NCs and PCs. Outcomes of caerulein pancreatitis were studied in lean rats coadministered interleukin (IL)-1β and keratinocyte chemoattractant/growth-regulated oncogene, triolein alone or with the lipase inhibitor orlistat.

RESULTS

NCs had higher fatty acids, IL-8 and IL-1β versus other fluids. Lipolysis of unsaturated triglyceride and resulting unsaturated fatty acids (UFA) oleic and linoleic acids induced necro-apoptosis at less than half the concentration in NCs but other agents did not do so at more than two times these concentrations. Cytokine coadministration resulted in higher pancreatic and lung inflammation than caerulein alone, but only triolein coadministration caused peripancreatic fat stranding, higher cytokines, UFAs, multisystem organ failure (MSOF) and mortality in 97% animals, which were prevented by orlistat.

CONCLUSIONS

UFAs, IL-1β and IL-8 are elevated in NCs. However, UFAs generated via peripancreatic fat lipolysis causes worse inflammation and MSOF, converting mild AP to SAP.

Distinctive roles of unsaturated and saturated fatty acids in hyperlipidemic pancreatitis

AIM: To investigate how the saturated and unsaturated fatty acid composition influences the susceptibility of developing acute pancreatitis.

METHODS: Primary pancreatic acinar cells were treated with low and high concentrations of different saturated and unsaturated fatty acids, and changes in the cytosolic Ca²⁺ signal and the expression of protein kinase C (PKC) were measured after treatment.

RESULTS: Unsaturated fatty acids at high concentrations, including oleic acid, linoleic acid, palmitoleic acid, docosahexaenoic acid, and arachidonic acid, induced a persistent rise in cytosolic Ca²⁺ concentrations in acinar cells. Unsaturated fatty acids at low concentrations and saturated fatty acids, including palmitic acid, stearic acid, and triglycerides, at low and high concentrations were unable to induce a rise in Ca²⁺ concentrations in acinar cells. Unsaturated fatty acids at high concentrations but not saturated fatty acids induced intra-acinar cell trypsin activation and cell damage and increased PKC expression.

CONCLUSION: At sufficiently high concentrations, unsaturated fatty acids were able to induce acinar cells injury and promote the development of pancreatitis. Unsaturated fatty acids may play a distinctive role in the pathogenesis of pancreatitis through the activation of PKC family members.

Lipolysis of visceral adipocyte triglyceride by pancreatic lipases converts mild acute pancreatitis to severe pancreatitis independent of necrosis and inflammation

Visceral fat necrosis has been associated with severe acute pancreatitis (SAP) for over 100 years; however, its pathogenesis and role in SAP outcomes are poorly understood. Based on recent work suggesting that pancreatic fat lipolysis plays an important role in SAP, we evaluated the role of pancreatic lipases in SAP-associated visceral fat necrosis, the inflammatory response, local injury, and outcomes of acute pancreatitis (AP). For this, cerulein pancreatitis was induced in lean and obese mice, alone or with the lipase inhibitor orlistat and parameters of AP induction (serum amylase and lipase), fat necrosis, pancreatic necrosis, and multisystem organ failure, and inflammatory response were assessed. Pancreatic lipases were measured in fat necrosis and were overexpressed in 3T3-L1 cells. We noted obesity to convert mild cerulein AP to SAP with greater cytokines, unsaturated fatty acids (UFAs), and multisystem organ failure, and 100% mortality without affecting AP induction or pancreatic necrosis. Increased pancreatic lipase amounts and activity were noted in the extensive visceral fat necrosis of dying obese mice. Lipase inhibition reduced fat necrosis, UFAs, organ failure, and mortality but not the parameters of AP induction. Pancreatic lipase expression increased lipolysis in 3T3-L1 cells. We conclude that UFAs generated via lipolysis of visceral fat by pancreatic lipases convert mild AP to SAP independent of pancreatic necrosis and the inflammatory response.

From moderately severe to severe hypertriglyceridemia induced acute pancreatitis: circulating miRNAs play role as potential biomarkers

The incidence of hypertriglyceridemia induced acute pancreatitis (HTAP) continues to rise in China. It has systemic complications and high mortality, making the early assessment of the severity of this disease even more important. Circulating microRNAs (miRNAs) could be novel, non-invasive biomarkers for disease progression judgment. This study aimed to identify the potential role of serum miRNAs as novel biomarkers of HTAP progression. HTAP patients were divided into two groups: moderately severe (HTMSAP) and severe (HTSAP), healthy people were used as control group. The serum miRNA expression profiles of these three groups were determined by microarray and verified by qRT-PCR. The functions and pathways of the targeted genes of deregulated miRNAs were predicted, using bioinformatics analysis; miRNA-mRNA network was generated. Moreover, the correlation between miR-181a-5p and pancreatitis metabolism related substances were studied and the serum concentration of inflammatory cytokines and miRNAs at different time points during the MSAP and SAP were investigated, respectively. Finally, the receiver operating characteristic (ROC) curve of miRNAs was studied. Significant changes in the serum concentration of the following miRNAs of HTAP patients (P<0.05) were discovered: miR24-3p, 361-5p, 1246, and 222-3p (constantly upregulated), and 181a-5p (constantly downregulated) (P<0.05). Bioinformatics analysis predicted that 13 GOs and 36 pathways regulated by overlap miRNAs were involved in glucose, fat, calcium (Ca++), and insulin metabolism (P<0.001). miRNA-mRNA network revealed that the overlap miRNAs targeted genes participating in pancreas metabolism and miR-181a-5p, the only downregulated miRNA, had good negative correlation with triglyceride (TG), total cholesterol (TC), and fast blood glucose (FBG), but a positive correlation with Ca++. When compared with inflammatory cytokines, the changes of all five overlap miRNAs were more stable. It was found that when used for evaluating the progression of HTAP, miRNAs showed good AUC. These data suggested that serum miRNAs have the potential to be excellent HTAP biomarkers.

Potential influence of intravenous lipids on the outcomes of acute pancreatitis

Parenteral nutrition (PN) has been associated with a higher rate of adverse outcomes compared with enteral feeding in patients with acute pancreatitis (AP). However, PN may be necessary when feeding via the enteral route is poorly tolerated or impossible, and PN is recommended as a second-line nutrition therapy in AP. Intravenous (IV) lipids are commonly used as a part of PN in patients with AP. While the adverse outcomes related to the use of PN in AP have commonly been attributed to infectious complications, data suggest that the unsaturated fatty acids in the triglycerides used in IV lipids may contribute to the development of organ failure. We discuss the clinical and experimental data on this issue and the alternative lipid emulsions that are being studied.

Role of pancreatic fat in the outcomes of pancreatitis

The role of obesity in relation to various disease processes is being increasingly studied, with reports over the last several years increasingly mentioning its association with worse outcomes in acute disease. Obesity has also gained recognition as a risk factor for severe acute pancreatitis (SAP).The mortality in SAP may be as high as 30% and is usually attributable to multi system organ failure (MSOF) earlier in the disease, and complications of necrotizing pancreatitis later [9-11]. To date there is no specific treatment for acute pancreatitis (AP) and the management is largely expectant and supportive. Obesity in general has also been associated with poor outcomes in sepsis and other pathological states including trauma and burns. With the role of unsaturated fatty acids (UFA) as propagators in SAP having recently come to light and with the recognition of acute lipotoxicity, there is now an opportunity to explore different strategies to reduce the mortality and morbidity in SAP and potentially other disease states associated with such a pathophysiology. In this review we will discuss the role of fat and implications of the consequent acute lipotoxicity on the outcomes of acute pancreatitis in lean and obese states and during acute on chronic pancreatitis.

Fatty acids of erythrocyte membrane in acute pancreatitis patients

AIM: To evaluate changes in the fatty acid composition of erythrocyte membrane phospholipids during severe and mild acute pancreatitis (AP) of alcoholic and nonalcoholic etiology.

METHODS: All consecutive patients with a diagnosis of AP and onset of the disease within the last 72 h admitted to the Hospital of Lithuanian University of Health Sciences between June and December 2007 were included. According to the Acute Physiology and Chronic Health Evaluation (APACHE II) scale, the patients were subdivided into the mild (APACHE II score < 7, n = 22) and severe (APACHE II score ≥ 7, n = 17) AP groups. Healthy individuals (n = 26) were enrolled as controls. Blood samples were collected from patients on admission to the hospital. Fatty acids (FAs) were extracted from erythrocyte phospholipids and expressed as percentages of the total FAs present in the chromatogram. The concentrations of superoxide dismutase and glutathione peroxidase were measured in erythrocytes.

RESULTS: We found an increase in the percentages of saturated and monounsaturated FAs, a decrease in the percentages of total polyunsaturated FAs (PUFAs) and n-3 PUFAs in erythrocyte membrane phospholipids of AP patients compared with healthy controls. Palmitic (C16:0), palmitoleic (C16:1n7cis), arachidonic (C20:4n6), docosahexaenoic (DHA, C22:6n3), and docosapentaenoic (DPA, C22:5n3) acids were the major contributing factors. A decrease in the peroxidation and unsaturation indexes in AP patients as well as the severe and mild AP groups as compared with controls was observed. The concentrations of antioxidant enzymes in the mild AP group were lower than in the control group. In severe AP of nonalcoholic etiology, the percentages of arachidic (C20:0) and arachidonic (C20:4n6) acids were decreased as compared with the control group. The patients with mild AP of nonalcoholic etiology had the increased percentages of total saturated FAs and gama linoleic acid (C18:3n6) and the decreased percentages of elaidic (C18:1n9t), eicosapentaenoic acid (EPA, C20:5n3), DPA (C22:5n3), DHA (C22:6n3) as well as total and n-3 PUFAs in erythrocyte membrane phospholipids.

CONCLUSION: The composition of FAs in erythrocyte membranes is altered during AP. These changes are likely to be associated with alcohol consumption, inflammatory processes, and oxidative stress.

Fibrosis reduces severity of acute-on-chronic pancreatitis in humans

BACKGROUND & AIMS

Acute pancreatitis (AP) and chronic pancreatitis (CP) share etiologies, but AP can be more severe and is associated with a higher rate of mortality. We investigated features of CP that protect against severe disease. The amount of intrapancreatic fat (IPF) is increased in obese patients and fibrosis is increased in patients with CP, so we studied whether fibrosis or fat regulate severity of AP attacks in patients with CP.

METHODS

We reviewed records from the University of Pittsburgh Medical Center/Presbyterian Hospital Autopsy Database (1998-2008) for patients with a diagnosis of AP (n = 23), CP (n = 35), or both (AP-on-CP; n = 15). Pancreatic histology samples from these patients and 50 randomly selected controls (no pancreatic disease) were analyzed, and IPF data were correlated with computed tomography data. An adipocyte and acinar cell Transwell coculture system, with or without collagen type I, was used to study the effects of fibrosis on acinar-adipocyte interactions. We studied the effects of nonesterified fatty acids (NEFAs) and adipokines on acinar cells in culture.

RESULTS

Levels of IPF were significantly higher in nonobese patients with CP than in nonobese controls. In patients with CP or AP-on-CP, areas of IPF were surrounded by significantly more fibrosis than in controls or patients with AP. Fat necrosis-associated peri-fat acinar necrosis (PFAN, indicated by NEFA spillage) contributed to most of the necrosis observed in samples from patients with AP; however, findings of peri-fat acinar necrosis and total necrosis were significantly lower in samples from patients with CP or AP-on-CP. Fibrosis appeared to wall off the fat necrosis and limit peri-fat acinar necrosis, reducing acinar necrosis. In vitro, collagen I limited the lipolytic flux between acinar cells and adipocytes and prevented increases in adipokines in the acinar compartment. This was associated with reduced acinar cell necrosis. However, NEFAs, but not adipokines, caused acinar cell necrosis.

CONCLUSIONS

Based on analysis of pancreatic samples from patients with CP, AP, or AP-on-CP and in vitro studies, fibrosis reduces the severity of acute exacerbations of CP by reducing lipolytic flux between adipocytes and acinar cells.

Fat necrosis generates proinflammatory halogenated lipids during acute pancreatitis

OBJECTIVE

To evaluate the generation of halogenated fatty acids in the areas of fat necrosis during acute pancreatitis and to evaluate the effects of these molecules on the ensuing inflammatory process.

BACKGROUND

Lipid mediators derived from adipose tissue have been implicated in the progression of acute pancreatitis, although their precise role remains unknown.

METHODS

Acute pancreatitis was induced in rats by intraductal infusion of 3.5% sodium taurocholate. Fatty acid chlorohydrins (FA-Cl) were measured in adipose tissue, ascitic fluid, and plasma by mass spectrometry. Chlorohydrins were also instilled in the rats' peritoneal cavity, and their effects on peritoneal macrophages activation and in systemic inflammation were evaluated. Finally, they have also been measured in plasma from human patients with acute pancreatitis.

RESULTS

Induced acute pancreatitis results in a substantial release not only of free fatty acids but also of the chlorohydrins of both oleic and linoleic acids from adipose tissue. In plasma, only the chlorohydrin of oleic acid was detected. Administration of 250-μM lipid chlorohydrins, which is the concentration found in ascitic fluid, induces the expression of TNFα and interleukin-1β in peritoneal macrophages and increases the systemic inflammatory response in pancreatitis. Finally, increased concentrations of oleic acid chlorohydrin have been found in plasma of human patients with pancreatitis.

CONCLUSIONS

During acute pancreatitis, adipose tissue release FA-Cl, which exacerbate the systemic inflammatory response.

Lipotoxicity causes multisystem organ failure and exacerbates acute pancreatitis in obesity

Obesity increases the risk of adverse outcomes during acute critical illnesses such as burns, severe trauma, and acute pancreatitis. Although individuals with more body fat and higher serum cytokines and lipase are more likely to experience problems, the roles that these characteristics play are not clear. We used severe acute pancreatitis as a representative disease to investigate the effects of obesity on local organ function and systemic processes. In obese humans, we found that an increase in the volume of intrapancreatic adipocytes was associated with more extensive pancreatic necrosis during acute pancreatitis and that acute pancreatitis was associated with multisystem organ failure in obese individuals. In vitro studies of pancreatic acinar cells showed that unsaturated fatty acids were proinflammatory, releasing intracellular calcium, inhibiting mitochondrial complexes I and V, and causing necrosis. Saturated fatty acids had no such effects. Inhibition of lipolysis in obese (ob/ob) mice with induced pancreatitis prevented a rise in serum unsaturated fatty acids and prevented renal injury, lung injury, systemic inflammation, hypocalcemia, reduced pancreatic necrosis, and mortality. Thus, therapeutic approaches that target unsaturated fatty acid-mediated lipotoxicity may reduce adverse outcomes in obese patients with critical illnesses such as severe acute pancreatitis.

Serum albumin prevents protein aggregation and amyloid formation and retains chaperone-like activity in the presence of physiological ligands

Although serum albumin has an established function as a transport protein, evidence is emerging that serum albumin may also have a role as a molecular chaperone. Using established techniques to characterize chaperone interactions, this study demonstrates that bovine serum albumin: 1) preferentially binds stressed over unstressed client proteins; 2) forms stable, soluble, high molecular weight complexes with stressed client proteins; 3) reduces the aggregation of client proteins when it is present at physiological levels; and 4) inhibits amyloid formation by both WT and L55P transthyretin. Although the antiaggregatory effect of serum albumin is maintained in the presence of physiological levels of Ca(2+) and Cu(2+), the presence of free fatty acids significantly alters this activity: stabilizing serum albumin at normal levels but diminishing chaperone-like activity at high concentrations. Moreover, here it is shown that depletion of albumin from human plasma leads to a significant increase in aggregation under physiologically relevant heat and shear stresses. This study demonstrates that serum albumin possesses chaperone-like properties and that this activity is maintained under a number of physiologically relevant conditions.

Serum Gc-globulin levels are reduced in patients with severe acute pancreatitis

BACKGROUND AND AIM

To investigate the role of group-specific component globulin (Gc-globulin) in the early process of severe acute pancreatitis (SAP).

PATIENTS AND METHODS

A total of 37 patients with SAP and 31 patients with mild acute pancreatitis (MAP) were enrolled in the study. Twenty healthy individuals served as controls. Blood samples were taken from SAP and MAP patients on the day of admission (day 1), day 7, and day 14. Serum total Gc-globulin levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

On admission, the total Gc-globulin levels of patients in the SAP group were 368 (270-455) mg/l (expressed as medians with interquartile range), which were significantly lower (P=0.007) compared with the control group [420 (299-585) mg/l]. In the SAP group, a significant decrease in serum total Gc-globulin was observed in patients who developed organ dysfunction [267 (242-306) mg/l] compared with patients who did not [414 (329-513) mg/l, P<0.001]. Patients with lower Gc-globulin levels were at a higher risk of developing organ dysfunction (P=0.005). Furthermore, serial measurements displayed increasing total Gc-globulin levels in survivors.

CONCLUSION

Decreased total Gc-globulin was linked to poor outcomes of SAP. These data support our hypothesis that Gc-globulin may play an important role in the early process of acute pancreatitis. Gc-globulin might be a novel target for prognosis and therapy of SAP.

Reduced plasma nonesterified fatty acid levels and the advent of an acute lung injury in mice after intravenous or enteral oleic acid administration

Although exerting valuable functions in living organisms, nonesterified fatty acids (NEFAs) can be toxic to cells. Increased blood concentration of oleic acid (OLA) and other fatty acids is detected in many pathological conditions. In sepsis and leptospirosis, high plasma levels of NEFA and low albumin concentrations are correlated to the disease severity. Surprisingly, 24 h after intravenous or intragastric administration of OLA, main NEFA levels (OLA inclusive) were dose dependently decreased. However, lung injury was detected in intravenously treated mice, and highest dose killed all mice. When administered by the enteral route, OLA was not toxic in any tested conditions. Results indicate that OLA has important regulatory properties on fatty acid metabolism, possibly lowering circulating fatty acid through activation of peroxisome proliferator-activated receptors. The significant reduction in blood NEFA levels detected after OLA enteral administration can contribute to the already known health benefits brought about by unsaturated-fatty-acid-enriched diets.