Serum amino acid profile in patients with acute pancreatitis

Multi-dimensional metabolomic profiling reveals dysregulated ornithine metabolism hallmarks associated with a severe acute pancreatitis phenotype

To reveal dysregulated metabolism hallmark that was associated with a severe acute pancreatitis (SAP) phenotype. In this study, LC-MS/MS-based targeted metabolomics was used to analyze plasma samples from 106 acute pancreatitis (AP) patients (34 mild, 38 moderate, and 34 severe) admitted within 48 hours from abdominal pain onset and 41 healthy controls. Temporal metabolic profiling was performed on days 1, 3, and 7 after admission. A random forest (RF) was performed to significantly determine metabolite differences between SAP and non-SAP (NSAP) groups. Mass spectrometry imaging (MSI) and immunohistochemistry were conducted for the examination of pancreatic metabolite and metabolic enzyme alterations, respectively, on necrosis and paracancerous tissues. Simultaneously determination of serum and pancreatic tissue metabolic alterations using an L-ornithine-induced AP model to discover metabolic commonalities. Twenty-two significant differential metabolites screened by RF were selected to build an accurate model for the prediction of SAP from NSAP (AUC = 0.955). Six of 22 markers were found by MSI with significant alterations in pancreatic lesions, reduced ornithine-related metabolites were also identified. The abnormally expressed arginase2 and ornithine transcarboxylase were further discovered in combination with time-course metabolic profiling in the SAP animal models, the decreased ornithine catabolites were found at a late stage of inflammation, but ornithine-associated metabolic enzymes were activated during the inflammatory process. The plasma metabolome of AP patients is distinctive, which shows promise for early SAP diagnosis. AP aggravation is linked to the activated ornithine metabolic pathway and its inadequate levels of catabolites in in-situ lesion.

Sodium pyruvate improves the plasma amino acid profile in rats with L-arginine-induced acute pancreatitis

Plasma amino acid levels are altered upon many pathological conditions including acute pancreatitis. It is unclear whether amino acids can be used as specific biomarker of acute pancreatitis severity or recovery. Development of acute pancreatitis is associated with mitochondrial dysfunction and decreased cytosolic ATP level. Sodium pyruvate is considered as a potential treatment of pancreatitis due to its ability to sustain mitochondrial oxidative and ATP-productive capacity in vitro. This study investigated the effect of sodium pyruvate on pancreatic morphology and plasma amino acid levels in rats with acute pancreatitis. Acute pancreatitis in rats was induced by administration of L-arginine (5 g/kg) Experimental treatment group received sodium pyruvate (1 g/kg) for 4 days. On day 8 of the experiment, animals were killed, blood was collected and plasma amino acid concentration was determined with high-performance liquid chromatography. Histological examination showed large areas of fibrosis in the pancreas of animals treated with L-arginine irrespectively of sodium pyruvate administration. Sodium pyruvate improved the plasma amino acid levels. Rats with acute pancreatitis had significantly lower levels of most essential and non-essential amino acids and increased glutamate and aspartate in plasma. Administration of sodium pyruvate completely or partially restored the levels of methionine, phenylalanine, tryptophan, leucine, isoleucine, aspartate, asparagine and ornithine levels, while increasing glutamine and serine to levels significantly higher than control. Plasma lysine, alanine, arginine and taurine remained unaffected in all experimental groups. Sodium pyruvate may be considered for use as a maintenance therapy in acute pancreatitis.

Zengye Decoction Attenuated Severe Acute Pancreatitis Complicated with Acute Kidney Injury by Modulating the Gut Microbiome and Serum Amino Acid Metabolome

Objective

To explore the effect and underlying mechanism of Zengye decoction (ZYD), a traditional formula from China, on the severe acute pancreatitis (SAP) rat model with acute kidney injury (AKI).

Methods

The SAP-AKI model was induced by 3.5% sodium taurocholate. Rats were treated with normal saline or ZYD twice and sacrificed at 36 h after modeling. Amylase, lipase, creatinine, blood urea nitrogen, kidney injury molecule 1(KIM-1), and multiple organs' pathological examinations were used to assess the protective effect of ZYD. Gut microbiome detected by 16S rRNA sequencing analysis and serum amino acid metabolome analyzed by liquid chromatography-mass spectrometry explained the underlying mechanism. The Spearman correlation analysis presented the relationship between microflora and metabolites.

Results

ZYD significantly decreased KIM-1(P < 0.05) and the pathological score of the pancreas (P < 0.05), colon (P < 0.05), and kidney (P < 0.05). Meanwhile, ZYD shifted the overall gut microbial structure (β-diversity, ANOSIM R = 0.14, P=0.025) and altered the microbial compositions. Notably, ZYD reduced the potentially pathogenic bacteria—Bacteroidetes, Clostridiales vadin BB60 group, and uncultured_Clostridiales_bacterium, but promoted the short-chain fatty acid (SCFA) producers—Erysipelotrichaceae, Bifidobacterium, Lactobacillus, and Moryella (all P < 0.05). Moreover, principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and hierarchical clustering analysis (HCA) presented a remarkable change in amino acid metabolome after SAP-AKI induction and an apparent regulation by ZYD treatment (R2Y 0.878, P=0.01; Q2 0.531, P=0.01). Spearman's correlation analysis suggested that gut bacteria likely influenced serum metabolites levels (absolute r > 0.4 and FDR P < 0.02).

Conclusions

ZYD attenuated SAP-AKI by modulating the gut microbiome and serum amino acid metabolome, which may be a promising adjuvant treatment.

Temporal metabolic trajectory analyzed by LC-MS/MS based targeted metabolomics in acute pancreatitis pathogenesis and Chaiqin Chengqi decoction therapy

BACKGROUND

Acute pancreatitis (AP) is an inflammatory disorder of pancreas that lacks effective specific drugs as well as gold standard laboratory tests for diagnosis and severity assessment. Chaiqin chengqi decoction (CQCQD) has been proven to alleviate the severity and mortality of AP, but its underlying mechanisms remain incompletely understood.

PURPOSE

To investigate the correlation between metabolic trajectories of the serum and pancreas, the metabolic pathways with respect to the onset and progression of AP, and investigate the effect of CQCQD in modulating the dysregulated pancreatic metabolism of AP.

METHODS

Serum and pancreas samples from cerulein-induced AP mice were collected for pathology, biochemical index assessment, LC-MS/MS based metabolomics and functional validation over the course of 1 - 24 h. The temporal trends of pancreatic and serum metabolites in AP were analyzed using Mfuzz clustering algorithm, and their associations were revealed by Pearson correlation analysis. The metabolic trajectories and pathways across multi-timepoints were analyzed by univariate and multivariate statistical analyses, and the AP-related metabolic pathways were further screened by metabolite correlation and network interaction analyses. Finally, the changes in metabolite levels and metabolic trajectory after CQCQD therapy were identified, and the altered expression of related metabolic enzymes was verified by RT-qPCR, western blotting, and immunohistochemistry.

RESULTS

Amino acid metabolism was significantly altered in the pancreas and serum of AP, but with different trends. The unsynchronized "open" and "closed" metabolic trajectories in pancreas and serumrevealed that metabolic processes occur earlier in peripheral rather than local tissue, with the most obvious changes occuring at 12 h in the pancreas which were also consistent with the inflammation score results. Several amino acid intermediates showed strong positive correlation between serum and pancreas, and therein serum cystathionine was positively correlated to 33 pancreatic metabolites. In particular, the correlations between the levels of pancreatic cystathionine and methionine, serine, and glutathione (GSH) emphasized the importance of trans-sulfuration to GSH metabolism for AP progression. CQCQD treatment reversed the metabolic trajectory of the pancreas, and also restored the levels of cystathionine and glutathione synthase.

CONCLUSION

Our results have defined a unique time-course metabolic trajectory for AP progression in both the serum and pancreas; it has also revealed a key role of CQCQD in reversing AP-associated metabolic alterations, thus providing new metabolic targets for the treatment and prognosis of AP.

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.

Exploring metabolic biomarkers and regulation pathways of acute pancreatitis using ultra-performance liquid chromatography combined with a mass spectrometry-based metabolomics strategy

Acute pancreatitis (AP), as a common kind of pancreas-based inflammatory disease, is accompanied by a serious and abnormal metabolism. However, the specific metabolic process of AP is still unclear. Novel and effective drugs against acute pancreatitis are urgently required. To explore the metabolic biomarkers and regulation pathways of acute pancreatitis, ultra-performance liquid chromatography (UPLC) combined with a mass spectrometry (MS)-based metabolomics strategy was used. Sixteen male adult Sprague-Dawley rats were divided into two groups: a sham operation group (SO) and an AP model group. The AP animal model was induced via the retrograde ductal infusion of 3.5% sodium taurocholate, and rats in the SO group were infused with 0.9% saline. After serum sample collection and sacrifice, a metabolomics strategy based on UPLC-MS was used to detect serum metabolites and metabolic pathways by comparing the SO and AP model groups through full-scan analysis. A total of 19 metabolites were detected in the serum for highlighting the differences between the two groups: l-arabitol, citric acid, isocitric acid, l-phenylalanine, l-tyrosine, dihydroxyacetone, l-valine, succinic acid, 3-hydroxybutyric acid, uric acid, acetylglycine, palmitic amide, homocysteine, d-glutamine, l-arginine, arachidonic acid, N-acetylserotonin, (R)-3-hydroxy-hexadecanoic acid, and d-mannose. Six crucial metabolic pathways, phenylalanine, tyrosine and tryptophan biosynthesis, arachidonic acid metabolism, glyoxylate and dicarboxylate metabolism and the citrate cycle, were involved; these have potential to become novel targets for the treatment of AP. The ingenuity pathway analysis (IPA) platform is used to gain insights into the metabolic targets in the system, referring to development disorders, cell-to-cell signaling and interactions, cellular assembly and organization, cell compromise, cell growth and proliferation, carbohydrate metabolism and others. It is suggested that UPLC-MS-based metabolomics is capable of accurately depicting the pathological mechanisms of acute pancreatitis, which can drive new drug development.

Acute pancreatitis (AP), as a common kind of pancreas-based inflammatory disease, is accompanied by a serious and abnormal metabolism.

Multi-dimensional, comprehensive sample extraction combined with LC-GC/MS analysis for complex biological samples: application in the metabolomics study of acute pancreatitis

Multi-dimensional sample extraction and optimal LC-GC/MS were combined to obtain as much sample information as possible for metabolomics applications.

The relationship between fasting plasma citrulline concentration and small intestinal function in the critically ill

Introduction

In this study, we aimed to evaluate whether fasting plasma citrulline concentration predicts subsequent glucose absorption in critically ill patients.

Methods

In a prospective observational study involving 15 healthy and 20 critically ill subjects, fasting plasma citrulline concentrations were assayed in blood samples immediately prior to the administration of a liquid test meal (1 kcal/ml; containing 3 g of 3-O-methylglucose (3-OMG)) that was infused directly into the small intestine. Serum 3-OMG concentrations were measured over the following 4 hours, with the area under the 3-OMG concentration curve (AUC) calculated as an index of glucose absorption.

Results

The groups were well matched in terms of age, sex and body mass index (BMI) (healthy subjects versus patients, mean (range) values: age, 47 (18 to 88) versus 49 (21 to 77) years; sex ratio, 60% versus 80% male; BMI, 25.2 (18.8 to 30.0) versus 25.5 (19.4 to 32.2) kg/m²). Compared to the healthy subjects, patients who were critically ill had reduced fasting citrulline concentration (26.5 (13.9 to 43.0) versus 15.2 (5.7 to 28.6) μmol/L; P < 0.01) and glucose absorption (3-OMG AUC, 79.7 (28.6 to 117.8) versus 61.0 (4.5 to 97.1) mmol/L/240 min; P = 0.05). There was no relationship between fasting citrulline concentration and subsequent glucose absorption (r = 0.28; P = 0.12).

Conclusions

Whereas both plasma citrulline concentrations and glucose absorption were reduced in critical illness, fasting plasma citrulline concentrations were not predictive of subsequent glucose absorption. These data suggest that fasting citrulline concentration does not appear to be a marker of small intestinal absorptive function in patients who are critically ill.

Glutamine supplementation in acute pancreatitis: a meta-analysis of randomized controlled trials

BACKGROUND

There is emerging evidence that glutamine supplementation should be considered in patients with acute and critical illness associated with a catabolic response. There are reports of glutamine supplementation in acute pancreatitis but the results of these studies are conflicting. The aim of this study was to systematically review the randomised controlled trials (RCT) of glutamine in patients with acute pancreatitis.

METHODS

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, SCOPUS and 3 major Chinese databases were searched. The outcomes studied were mortality, total infectious complications, and length of hospital stay. A random effects model was used for meta-analysis of the outcomes in the included trials. A number of pre-specified subgroup analyses were also conducted. The summary estimates were reported as risk ratio (RR) for categorical variables and mean difference (MD) for continuous variables together with the corresponding 95% confidence interval.

RESULTS

Twelve RCT that enrolled 505 patients with acute pancreatitis were included in the final analysis. Overall, glutamine supplementation resulted in a significantly reduced risk of mortality (RR 0.30; 95% CI, 0.15 to 0.60; P < 0.001) and total infectious complications (RR 0.58; 95% CI, 0.39 to 0.87; P = 0.009) but not length of hospital stay (MD -1.35; 95% CI, -3.25 to 0.56, P = 0.17). In the subgroup analyses, only patients who received parenteral nutrition and those who received glutamine in combination with other immunonutrients demonstrated a statistically significant benefit in terms of all the studied outcomes.

CONCLUSIONS

This meta-analysis demonstrates a clear advantage for glutamine supplementation in patients with acute pancreatitis who receive total parenteral nutrition. Patients with acute pancreatitis who receive enteral nutrition do not require glutamine supplementation. Further studies are warranted to determine whether patients who receive combined enteral and parenteral nutrition need glutamine supplementation.

Amino acid transporters expression in acinar cells is changed during acute pancreatitis

Pancreatic acinar cells accumulate amino acids against a marked concentration gradient to synthesize digestive enzymes. Thus, the function of acinar cells depends on amino acid uptake mediated by active transport. Despite the importance of this process, pancreatic amino acid transporter expression and cellular localization is still unclear. We screened mouse pancreas for the expression of genes encoding amino acid transporters. We showed that the most highly expressed transporters, namely sodium dependent SNAT3 (Slc38a3) and SNAT5 (Slc38a5) and sodium independent neutral amino acids transporters LAT1 (Slc7a5) and LAT2 (Slc7a8), are expressed in the basolateral membrane of acinar cells. SNAT3 and SNAT5, LAT1 and LAT2 are expressed in acinar cells. Additional evidence that these transporters are expressed in mature acinar cells was gained using acinar cell culture and acute pancreatitis models. In the acute phase of pancreatic injury, when acinar cell loss occurs, and in an acinar cell culture model, which mimics changes occurring during pancreatitis, SNAT3 and SNAT5 are strongly down-regulated. LAT1 and LAT2 were down-regulated only in the in vitro model. At protein level, SNAT3 and SNAT5 expression was also reduced during pancreatitis. Expression of other amino acid transporters was also modified in both models of pancreatitis. The subset of transporters with differential expression patterns during acute pancreatitis might be involved in the injury/regeneration phases. Further expression, localization and functional studies will follow to better understand changes occurring during acute pancreatitis. These findings provide insight into pancreatic amino acid transport in healthy pancreas and during acute pancreatitis injury.

The role of nitric oxide in the physiology and pathophysiology of the exocrine pancreas

SIGNIFICANCE

Nitric oxide (NO), a ubiquitous gaseous signaling molecule, contributes to both pancreatic physiology and pathophysiology.

RECENT ADVANCES

The present review provides a general overview of NO synthesis, signaling, and function. Further, it specifically discusses NO metabolism and its effects in the exocrine pancreas and focuses on the role of NO in the pathogenesis of acute pancreatitis and pancreatic ischemia/reperfusion injury.

CRITICAL ISSUES

Unfortunately, the role of NO in pancreatic physiology and pathophysiology remains controversial in numerous areas. Many questions regarding the messenger molecule still remain unanswered.

FUTURE DIRECTIONS

Probably the least is known about the downstream targets of NO, which need to be identified, especially at the molecular level.

Assessment of Small Bowel Function in Critical Illness: Potential Role of Citrulline Metabolism

Small intestinal function in critically ill patients should ideally be assessed in order to determine the preferred feeding route, timing, and composition of enteral nutrition. Additionally, evaluation of small bowel function may lead to new insights aimed to maintain enterocyte integrity. Critically ill patients are likely to have impaired enterocyte function mainly as a consequence of diminished splanchnic blood flow associated with mucosal hyperpermeability and bacterial translocation, a pathological state believed to be pivotal in the development of sepsis and multiple organ dysfunction syndrome (MODS). However, feasible and validated clinical tools to reliably assess enterocyte function are lacking. This explorative review discusses the promising role of citrulline, a nonprotein amino acid almost exclusively generated by the enterocyte, as a biomarker reflecting enterocyte function in critically ill patients. Citrulline metabolism, its potential as enterocyte biomarker, and literature on citrulline in critically illness will be discussed. Finally, a novel test for enterocyte function, the citrulline generation test (enterocytic citrulline production upon stimulation with enteral or intravenous glutamine) will be considered briefly.

Decreased serum essential and aromatic amino acids in patients with chronic pancreatitis

AIM: To investigate the influence of chronic pancreatitis (CP) on serum concentrations of amino acids.

METHODS: Thirty-five male patients with alcoholic CP and 21 healthy male subjects were examined. Serum concentrations of amino acids were assayed by ion-pair high-performance liquid chromatography with mass detection.

RESULTS: Serum glutamate concentration was increased in CP patients as compared to controls. In contrast, serum concentrations of glutamine, histidine, tyrosine, proline, tryptophan and threonine were significantly decreased in CP patients. A trend towards decreasing concentrations of serum lysine, alanine, methionine and valine as well as for total serum amino acids was observed. The sum of aromatic and the sum of essential amino acid concentrations were significantly lower in CP patients than in controls.

CONCLUSION: CP leads to decreased serum concentrations of several amino acids, such as essential and aromatic serum amino acids, most likely due to decreased exocrine function.

Inhibition of arginase activity ameliorates L-arginine-induced acute pancreatitis in rats

OBJECTIVES

Intraperitoneal (IP) injection of 3.5 g/kg L-arginine (known to induce acute pancreatitis) in rats will result in much greater increases in serum ornithine versus citrulline concentration (Crit Care Med. 2008;36:2117-2127). These data indicate a major role of arginase in the catabolism of L-arginine. Therefore, we tested the effects of the irreversible arginase inhibitor (+)-S-2-amino-6-iodoacetamidohexanoic acid (AIHA) on L-arginine-induced acute pancreatitis.

METHODS

The inhibitory effect of AIHA on arginase activity was tested on rat liver homogenate and purified bovine arginase. Male Wistar rats were administered 15 mg/kg AIHA or its vehicle IP 1 hour before the injection of physiological saline or 3.5 g/kg L-arginine IP. Laboratory and histological parameters of pancreatitis were determined 24 hours after the last injection.

RESULTS

Sixty micromolars of AIHA (equimolar to an in vivo dose of 15 mg/kg) significantly inhibited arginase activity by about 25%. Pretreatment with AIHA significantly ameliorated pancreatic damage caused by L-arginine administration. It decreased pancreatic weight/body weight ratio, pancreatic glutathione peroxidase and myeloperoxidase activities, and histological damage. Administration of AIHA in itself significantly increased levels of pancreatic heat shock proteins.

CONCLUSIONS

Pretreatment with AIHA reduces the severity of L-arginine-induced pancreatitis most likely by inhibiting arginase activity.

Nutritional strategies in severe acute pancreatitis: a systematic review of the evidence

Nutrition in severe acute pancreatitis is a critical aspect in the management of this condition. This review aims to systematically review the evidence available to inform the use of nutritional support in severe acute pancreatitis. High quality (level 1) evidence supports naso-jejunal enteral nutrition (NJ-EN) over parenteral nutrition (PN) reducing infectious morbidity and showing a trend towards reduced organ failure although there is no detectable difference in mortality. Trial data may underestimate benefit as patients are often recruited with predicted rather than proven severe disease. NJ-EN is safe when started immediately (level 3 evidence). NJ-EN is often impractical and naso-gastric (NG) feeding seems to be equivalent in terms of safety and outcomes whilst being more practical (level 2 evidence). Regarding feed supplementation, probiotic feed supplementation is not beneficial (level 1 evidence) the and may cause harm with excess mortality (level 2 evidence). No evidence exists to confirm benefit of the addition of prokinetics in severe acute pancreatitis (SAP) although their use is proven in other critically ill patients. Level 2 evidence does not currently support the use of combination immuno-nutrition though further work on individual agents may provide differing results. Level 2 evidence does not support intravenous supplementation of anti-oxidants and has demonstrated that these too may cause harm.