Efficacy of serum nitric oxide level estimation in assessing the severity of necrotizing pancreatitis

Resveratrol supplementation and acute pancreatitis: A comprehensive review

Resveratrol, a natural polyphenolic ingredient extracted from herbs, suppresses oxidative stress and inflammation. We performed a comprehensive review to find any evidence about the effects of Resveratrol on acute pancreatitis (AP). Resveratrol has been found to directly impact cytokine generation. As these factors play a crucial role in the pathophysiology of AP, resveratrol might attenuate AP and its complications. Mechanistically, resveratrol exerts its pharmacological effects through anti-inflammatory and antioxidant mechanisms via interaction with different signaling molecules and transcription factors. Indeed, resveratrol might prove to be an effective therapeutic component for AP treatment in the future. In this review, we shed light on potential most recent pathways through which resveratrol might impact the management and control of AP.

Clinical practice guideline: management of acute pancreatitis

ABSTRACT

There has been an increase in the incidence of acute pancreatitis reported worldwide. Despite improvements in access to care, imaging and interventional techniques, acute pancreatitis continues to be associated with significant morbidity and mortality. Despite the availability of clinical practice guidelines for the management of acute pancreatitis, recent studies auditing the clinical management of the condition have shown important areas of noncompliance with evidence-based recommendations. This underscores the importance of creating understandable and implementable recommendations for the diagnosis and management of acute pancreatitis. The purpose of the present guideline is to provide evidence-based recommendations for the management of both mild and severe acute pancreatitis as well as the management of complications of acute pancreatitis and of gall stone-induced pancreatitis.

Compliance with Evidence-Based Guidelines in Acute Pancreatitis: an Audit of Practices in University of Toronto Hospitals

Despite existing evidence-based practice guidelines for the management of acute pancreatitis, clinical compliance with recommendations is poor. We conducted a retrospective review of 248 patients admitted between 2010 and 2012 with acute pancreatitis at eight University of Toronto affiliated hospitals. We included all patients admitted to ICU (52) and 25 ward patients from each site (196). Management was compared with the most current evidence used in the Best Practice in General Surgery Management of Acute Pancreatitis Guideline. Fifty-six patients (22.6 %) had only serum lipase tested for biochemical diagnosis. Admission ultrasound was performed in 174 (70.2 %) patients, with 69 (27.8 %) undergoing ultrasound and CT. Of non-ICU patients, 158 (80.6 %) were maintained nil per os, and only 18 (34.6 %) ICU patients received enteral nutrition, commencing an average 7.5 days post-admission. Fifty (25.5 %) non-ICU patients and 25 (48.1 %) ICU patients received prophylactic antibiotics. Only 24 patients (22.6 %) with gallstone pancreatitis underwent index admission cholecystectomy. ERCP with sphincterotomy was under-utilized among patients with biliary obstruction (16 [31 %]) and candidates for prophylactic sphincterotomy (18 [22 %]). Discrepancies exist between the most current evidence and clinical practice within the University of Toronto hospitals. A guideline, knowledge translation strategy, and assessment of barriers to clinical uptake are required to change current clinical practice.

Astragaloside IV ameliorates acute pancreatitis in rats by inhibiting the activation of nuclear factor-κB

This study aimed to investigate the effects of astragaloside IV (AS-IV; 3-O-β-D-xylopyranosyl-6-O-β-D-glucopyranosylcycloastragenol), which has been reported to have comprehensive pharmacological functions, on sodium taurocholate (NaTc)/L-arginine (L-Arg)-induced acute pancreatitis (AP) in rats in vivo and in rat pancreatic acinar cells in vitro. NaTc-induced experimental AP was induced in rats by injecting 4% NaTc (0.1 ml/100 g) in the retrograde direction of the biliopancreatic duct. L-Arg-induced experimental AP was induced in rats by 2 intraperitoneal injections of 20% L-arg (3 g/kg), with an interval of 1 h between the injections. The rats were pre-treated AS-IV (50 mg/kg) or the vehicle (DMSO) 2 h prior to the induction of AP. Enzyme-linked immunosorbent assay, H&E staining, myeloperoxidase (MPO) activity, reverse transcription-quantitative PCR, western blot analysis and immunohistochemistry were used to evaluate the effects of AS-IV on AP. The results revealed that treatment with AS-IV significantly reduced serum amylase and lipase levels, pancreatic pathological alterations, the secretion of pro-inflammatory cytokines, MPO activity, and the protein expression of nuclear factor-κB (NF-κB) in vivo. Moreover, pre-treatment with AS-IV significantly increased the expression levels of manganese superoxide dismutase and cuprum/zinc superoxide dismutase. In the in vitro experiment, treatment of the cells with AS-IV aslo reduced rat pancreatic acinar cell necrosis and nuclear NF-κB activity, and enhanced the protein expression of superoxide dismutase. In conclusion, this study indicates that the protective effects of AS-IV on experimental AP in rats may be closely related to the inhibition of NF-κB. In addition, our results indicate that AS-IV may exert potential antioxidant effects on AP. Therefore, AS-IV may be an effective therapeutic agent for AP.

Risk factors for pancreatic infection in patients with severe acute pancreatitis: an analysis of 163 cases

OBJECTIVE

We aimed to identify the risk factors for predicting pancreatic infection in patients with severe acute pancreatitis (SAP).

METHODS

In all, 163 patients with SAP were included and divided into two groups based on the presence or absence of pancreatic infection. Their demographic and clinical characteristics, laboratory examination results, complications and treatment modalities were collected from their medical records. Variables were initially screened by univariate analysis and those with statistical significance were then filtered by multivariate analysis to determine the independent risk factors for pancreatic infection in SAP.

RESULTS

Patients having SAP with pancreatic infection had a lower partial pressure of arterial carbon dioxide (PaCO2 ), peripheral white blood cell count and alkaline phosphatase levels, together with a higher computed tomography severity index (CTSI) than those without pancreatic infection, while their lactate dehydrogenase (LDH) levels and blood urea nitrogen were much higher. Pancreatic infection was also more common in patients receiving late fluid resuscitation than in those receiving early fluid resuscitation. Multivariate analyses revealed that increased LDH level, high CTSI, delayed fluid resuscitation and hypoxemia were independent risk factors for pancreatic infection in SAP. The sensitivity, specificity, positive and negative predictive values for a model combining the parameters in predicting pancreatic infection were 84%, 97%, 88% and 96%, respectively, with a cut-off value of 0.393, and the area under the receiver operating characteristic curve was 0.923.

CONCLUSION

Increased LDH, high CTSI, delayed fluid resuscitation and hypoxemia are independent risk factors for predicting pancreatic infection in patients with SAP.

Treatment with ginkgo biloba extract protects rats against acute pancreatitis-associated lung injury by modulating alveolar macrophage

INTRODUCTION

Acute pancreatitis (AP) protease release induces lung parenchymal destruction via inflammatory mediators. Ginkgo biloba has been reported to have anti-inflammatory effects.

AIM

To evaluate the effect of ginkgo biloba extract on experimental acute pancreatitis-associated lung injury in the rat and to investigate the underlying mechanisms.

MATERIAL AND METHODS

Acute pancreatitis was induced in rats by injection of 5% sodium taurocholate into the biliary pancreatic duct. Ginkgo biloba extract (GBE) was administered and pancreas and lung injury were assessed by histological examination. Alveolar macrophages were harvested by bronchoalveolar lavage. Specificity fluorescent probe DAF-FM-DA was applied to observe nitric oxide (NO) bioavailability in alveolar macrophage. The expression of tumour necrosis factor α (TNF-α) and macrophage migration inhibitory factor (MIF) protein in alveolar macrophage was studied by ELISA.

RESULTS

In sodium taurocholate-induced acute pancreatitis, treatment with GBE significantly protected rats against lung injury associated with pancreatitis in histological sections. Ginkgo biloba extract had a tendency to down-regulate NO bioavailability compared with the AP group, but without statistical significance. Moreover, TNF-α and MIF at protein levels in alveolar macrophage with GBE treatment were decreased compared with the AP group.

CONCLUSIONS

These results suggest that GBE could effectively protect rats against acute pancreatitis-associated lung injury. The GBE may inhibit excessive activation of alveolar macrophages from acute pancreatitis-associated lung injury through down-regulation of generation of NO, TNF-α and MIF. These findings suggest that ginkgo biloba extract is a suitable candidate as an effective strategy against acute pancreatitis-associated lung injury.

The effects of resveratrol on tissue injury, oxidative damage, and pro-inflammatory cytokines in an experimental model of acute pancreatitis

Acute pancreatitis (AP) is an acute inflammatory condition that results from the digestion of pancreatic tissue by its own enzymes released from the acinar cells. The objective of this study was to investigate the effects of resveratrol on oxidative damage, pro-inflammatory cytokines, and tissue injury involved with AP induced in a rat model using sodium taurocholate (n = 60). There were three treatment groups with 20 rats per group. Groups I and II received 3% sodium taurocholate solution, while group III underwent the same surgical procedure yet did not receive sodium taurocholate. In addition, group II received 30 mg/kg resveratrol solution. Rats were sacrificed at 2, 6, 12, and 24 h time points following the induction of AP. Blood and pancreatic tissue samples were collected and subjected to biochemical assays, Western blot assays, and histopathologic evaluations. Resveratrol did not reduce trypsin levels and prevent tissue damage. Resveratrol prevented IκB degradation (except for 6 h) and decreased nuclear factor-κB (NF-κB), activator protein-1 (AP-1) (except for 24 h), and levels of TNF-α, IL-6 (except for 24 h), and iNOS in the pancreatic tissue at all time points (P < 0.05). Serum nitric oxide (NO) levels were reduced as well (P < 0.05). Thus, we concluded that resveratrol did not reduce trypsin levels and did not prevent tissue injury despite the reduction in oxidative damage and pro-inflammatory cytokine levels detected in this model of AP.

Serum nitric oxide levels in patients with benign and malignant biliary disease: a prospective single center study

BACKGROUND

Despite advances in new diagnostic modalities, the differentiation of malignant from benign causes of biliary obstruction still remains difficult. The nitric oxide (NO) system is considered to be an important component in mediating cytokine activation of macrophages in inflammation. It also modulates tumorigenesis and regulates cell proliferation, angiogenesis, survival, and DNA repair. Although NO and its role in pancreatobiliary disorders has not been studied previously, the present study is designed to evaluate NO synthesis and metabolism in patients with biliary obstruction and to determine its usefulness in differentiating between benign and malignant causes of biliary obstruction.

MATERIALS AND METHODS

Seventy-nine consecutive patients (60 malignant and 19 benign) with a history of biliary obstruction either with a benign or a malignant cause and 23 age-matched and sex-matched controls were included in this prospective study. NO metabolites, and conventional inflammation and tumor markers were determined.

RESULTS

In patients with malignant biliary obstruction (MBO), serum NO metabolites were found to be significantly elevated (P<0.001). The receiver operating characteristic analysis showed that an NO level of 1.095 was the best cut-off value for predicting a malignant biliary stricture with a sensitivity of 78.3% and a specificity of 84.2% (area under the curve=0.821). Correlation analysis suggested that carbohydrate antigen 19-9 and carcinoembryonic antigen levels were correlated with NO levels for differentiating benign from malignant cause of biliary obstruction.

CONCLUSIONS

Serum NO-associated tissue injury might be associated with the development of pancreatobiliary neoplasia by creating a local environment that is enriched with reactive oxygen species, cytokines, and other growth factors that may promote endothelial cell apoptosis. Moreover, serum NO levels may be used as an adjunctive marker to identify malignant causes of the obstructive jaundice.

Audit of patients with severe acute pancreatitis admitted to an intensive care unit

BACKGROUND

Severe acute pancreatitis (SAP) is a disease with high morbidity and mortality. We undertook a study of patients with SAP admitted to the intensive care unit (ICU) of a tertiary referral hospital.

METHODS

Between 2002 and 2007, 50 patients with SAP were admitted in our intensive care unit (ICU). Data were collected from their medical records and their clinical profile, course and outcome were retrospectively analyzed. Patients were categorized into survivor and nonsurvivor groups, and were further classified based on interventions such as percutaneous drainage and surgical necrosectomy.

RESULTS

SAP contributed 5 % of total ICU admissions during the study period. Median age of survivors (n = 20) was 34 against 44 years in nonsurvivors (n = 30). Median Acute Physiology and Chronic Health Evaluation (APACHE) II score in nonsurvivors was 16.5 (8-32) vs. 12.5 (5-20) in survivors (p = 0.002). Patients with APACHE II score ≥12 had mortality >80 % compared to 23 % with score <12 (p < 0.001). Median Sequential Organ Failure Assessment (SOFA) scores on admission and on days 3, 7, 14, and 21 were significantly higher in nonsurvivors compared to survivors (p < 0.05). Mean (SD) intraabdominal pressure was 23 (3.37) mmHg in nonsurvivors vs. 19.05 (2.51) in survivors (p < 0.05). Patients with renal failure had significant mortality (p < 0.001). Length of ICU stay, requirement for vasopressor, total parenteral nutrition, and the amount of blood and blood product transfusions differed significantly between patients with and without intervention.

CONCLUSIONS

APACHE II and SOFA scores and other clinical data correlated with outcome in SAP admitted to ICU.

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.

Soluble triggering receptor expressed on myeloid cells in severe acute pancreatitis: a biological marker of infected necrosis

PURPOSE

The diagnosis and treatment of secondary infection of pancreatic necrotic tissue remain a major challenge. The level of soluble triggering receptor expressed on myeloid cells (sTREM-1) in fine needle aspiration (FNA) fluid may be a good marker of infected necrosis.

METHODS

Patients with a clinical suspicion of secondary infection of necrotic tissue were enrolled. The serum levels of C-reactive protein, amylase, procalcitonin (PCT), and sTREM-1 and the fluid levels of sTREM-1, PCT, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and amylase were examined. When infected necrosis was defined, the first step was percutaneous or endoscopic drainage. If there was no improvement after 72 h, an open necrosectomy was performed.

RESULTS

In 30 patients with suspected infection, 18 patients were diagnosed as having secondary infection of necrotic tissue. The levels of sTREM-1 and PCT in FNA fluid were found to have the closest correlation with the diagnosis of infected necrosis [sTREM-1: area under the receiver operating characteristic curve (AUC) 0.972; 95% confidence interval (95%CI) 0.837-1.000; PCT: AUC 0.903; 95%CI 0.670-0.990, P > 0.05]. A fluid sTREM-1 cutoff value of 285.6 pg/ml had a sensitivity of 94.4% and a specificity of 91.7%. In a multiple logistic regression analysis, an sTREM-1 level of more than 285 pg/ml and a PCT level of more than 2.0 ng/ml in FNA fluid were independent predictors of infected necrosis.

CONCLUSIONS

The fluid level of sTREM-1 will help in the rapid and accurate diagnosis of secondary infection of necrotic tissue in patients with severe acute pancreatitis (SAP).

Cardiocirculatory pathophysiological mechanisms in severe acute pancreatitis

Acute pancreatitis (AP) is a common and potentially lethal acute inflammatory process. Although the majority of patients have a mild episode of AP, 10%-20% develop a severe acute pancreatitis (SAP) and suffer systemic inflammatory response syndrome (SIRS) and/or pancreatic necrosis. The main aim of this article is to review the set of events, first localized in the pancreas, that lead to pancreatic inflammation and to the spread to other organs contributing to multiorganic shock. The early pathogenic mechanisms in SAP are not completely understood but both premature activation of enzymes inside the pancreas, related to an impaired cytosolic Ca²⁺ homeostasis, as well as release of pancreatic enzymes into the bloodstream are considered important events in the onset of pancreatitis disease. Moreover, afferent fibers within the pancreas release neurotransmitters in response to tissue damage. The vasodilator effects of these neurotransmitters and the activation of pro-inflammatory substances play a crucial role in amplifying the inflammatory response, which leads to systemic manifestation of AP. Damage extension to other organs leads to SIRS, which is usually associated with cardiocirculatory physiology impairment and a hypotensive state. Hypotension is a risk factor for death and is associated with a significant hyporesponsiveness to vasoconstrictors. This indicates that stabilization of the patient, once this pathological situation has been established, would be a very difficult task. Therefore, it seems particularly necessary to understand the pathological mechanisms involved in the first phases of AP to avoid damage beyond the pancreas. Moreover, efforts must also be directed to identify those patients who are at risk of developing SAP.

Prediction of mortality in acute pancreatitis: a systematic review of the published evidence

OBJECTIVE

In this review, we focus on studies that examined such prognostic indices in relation to predicting a fatal outcome from pancreatitis.

SUMMARY BACKGROUND DATA

Acute pancreatitis (AP) is a common emergency, and early identification of high-risk patients can be difficult. For this reason, a plethora of different prognostic variables and scoring systems have been assessed to see if they can reliably predict the severity of pancreatitis and/or subsequent mortality.

METHODS

All studies that focused on AP, including retrospective series and prospective trials, were retrieved and analysed for factors that could influence mortality. Articles that analysed factors influencing the severity of the disease or the manifestation of disease-related complications were excluded.

RESULTS

58 articles meeting the inclusion criteria were identified. Among the various factors investigated, APACHE II seemed to have the highest positive predictive value (69%). However, most prognostic variables and scores showed high negative predictive values but suboptimal values for positive predictive power.

CONCLUSIONS

Despite the proliferation of scoring systems for grading AP, none are ideal for the prediction of mortality. With the exception of the APACHE II, the other scores and indexes do not have a high degree of sensitivity, specificity and predictive values.

Expression of nitric oxide synthase isoforms and nitric oxide production in acute pancreatitis and associated lung injury

BACKGROUND/AIMS

The role of nitric oxide (NO) has been increasingly implicated in the pathophysiology of acute pancreatitis (AP). Studies have shown increased NO production in AP although not all are agreeable on whether NO is beneficial or detrimental in AP. This study aims to profile NO production and NO synthase (NOS) expression in the pancreas and lungs in the progression of AP in mice to gain insights to the role played by different NOS isoforms.

METHODS

AP was induced in mice by hourly administration of cerulein. NO production was determined by measuring the total nitrite and nitrate (NOx) content while NOS expression was measured by Western blot.

RESULTS

Pancreatic NO production increased sharply and was sustained throughout AP. iNOS expression was greatly increased while eNOS was downregulated at the later stages. In the lungs, there was an unexpected early increase in the constitutive NOS expression; however iNOS was also significantly overexpressed at the later time point along with a significant increase in NO. Acinar cells were found to overproduce NO in response to cerulein hyperstimulation with iNOS again being the major contributor.

CONCLUSION

These data show that NO production and NOS expression are differentially regulated temporally and in magnitude in the pancreas and lungs in response to cerulein hyperstimulation which suggests differing roles for each NOS isoform. and IAP.

Cardiovascular homeostasis in hypotension associated with initial stages of severe acute pancreatitis

OBJECTIVES

To identify the mechanisms underlying hypotension during the early phase of severe acute pancreatitis (SAP) by analyzing whether an impaired response to vasoactive substances occurs in this pathological process.

METHODS

Experimental SAP was induced by infusing 5% sodium taurocholate through the main pancreatic duct in rats. Once mean arterial pressure (MAP) in animals with pancreatitis was reduced, different vasoactive substances and inhibitors were administered.

RESULTS

Administration of the nonspecific nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester caused a similar increase in MAP in rats with pancreatitis and control rats, whereas inducible nitric oxide synthase inhibition did not cause changes in MAP. Moreover, the hypertensive response to endothelin and angiotensin II was lower in pancreatitis. Inhibition of angiotensin II synthesis by the angiotensin-converting enzyme inhibitor perindopril in animals with pancreatitis caused severe hypotension, causing death in 40% of them. Finally, pressor hyporesponsiveness to angiotensin II in animals with pancreatitis was avoided by previous administration of perindopril and N omega-nitro-L-arginine methyl ester.

CONCLUSIONS

The SAP-induced hypotension is associated with a deficient pressor responsiveness to angiotensin II and endothelin-1. The renin-angiotensin system plays an important role in the control of MAP in animals with pancreatitis.

Value of pancreatic antibiotic concentration in treatment of secondary infection of serve acute pancreatitis

Secondary pancreatic infection represents the most serious complication with fatal outcome in severe acute pancreatitis (SAP). Preventing and curing secondary infection of pancreas is the key obstacle to minimize the mortality of these patients. The studies on blood-pancreatic juice barrier as well as penetration and pancreatic tissue concentration of antibiotics have improved the antibiotic prophylaxis or treatment of pancreatic infection. In the future, potential therapeutics that can enhance the antibiotic concentration and efficacy may help to prevent and treat the secondary infection of SAP.

Prophylactic use of antibiotics in treatment of severe acute pancreatitis

Necrotic pancreatic infection is the most serious complication of severe acute pancreatitis (SAP). Although prophylactic antibiotics are widely used to reduce its death rate, its practical efficiency still remains controversial. Therefore, the clinical experiences with prophylactic use of antibiotics are summarized in this paper, hoping to offer certain guides to its treatment. However, results from recent studies do not support prophylactic use of antibiotics in all cases of necrotic pancreatic infection and suggest that only imipenem or meropenem can be used for no more than three weeks in patients with their pancreatic necrosis area >30% or in patients with biliogenic pancreatitis to decrease the risk of necrotic infection and its mortality rate.

Severe acute pancreatitis: Pathogenetic aspects and prognostic factors

Approximately 20% of patients with acute pancreatitis develop a severe disease associated with complications and high risk of mortality. The purpose of this study is to review pathogenesis and prognostic factors of severe acute pancreatitis (SAP). An extensive medline search was undertaken with focusing on pathogenesis, complications and prognostic evaluation of SAP. Cytokines and other inflammatory markers play a major role in the pathogenesis and course of SAP and can be used as prognostic markers in its early phase. Other markers such as simple prognostic scores have been found to be as effective as multifactorial scoring systems (MFSS) at 48 h with the advantage of simplicity, efficacy, low cost, accuracy and early prediction of SAP. Recently, several laboratory markers including hematocrit, blood urea nitrogen (BUN), creatinine, matrix metalloproteinase-9 (MMP-9) and serum amyloid A (SAA) have been used as early predictors of severity within the first 24 h. The last few years have witnessed a tremendous progress in understanding the pathogenesis and predicting the outcome of SAP. In this review we classified the prognostic markers into predictors of severity, pancreatic necrosis (PN), infected PN (IPN) and mortality.

Nitric oxide pathways and evidence-based perturbations in acute pancreatitis

Nitric oxide (NO) is a gaseous neurotransmitter, a vasodilator and paracrine regulator. In the pancreas, NO regulates normal pancreatic exocrine secretion, endocrine pancreatic insulin secretion and pancreatic microvascular blood flow. NO has multiple species and is produced de novo by 3 NO synthase enzymes. Endothelial NO synthase reduces the severity of the initial phase of experimental acute pancreatitis (AP). Cigarette smoking and chronic alcohol use disrupt normal NO pathways and are associated with pancreatitis and pancreatic cancer. The aims of this minireview are to describe normal intrapancreatic NO pathways, perturbations during experimental AP and due to epidemiological factors associated with pancreatic pathology, and the clinical implications of NO on AP.

Serum amino acid profile in patients with acute pancreatitis

Patients in the early phase of acute pancreatitis (AP) have reduced serum levels of arginine and citrulline. This may be of patho-biological importance, since arginine is the substrate for nitric oxide, which in turn is involved in normal pancreatic physiology and in the inflammatory process. Serum amino acid spectrum was measured daily for five days and after recovery six weeks later in 19 patients admitted to the hospital for acute pancreatitis. These patients had abnormal levels of most amino acids including arginine, citrulline, glutamine and glutamate. Phenylalanine and glutamate were increased, while arginine, citrulline, ornithine and glutamine were decreased compared to levels after recovery. NO(2)/NO(3) concentration in the urine, but not serum arginase activity, was significantly increased day 1 compared to day 5 after admission. Acute pancreatitis causes a disturbance of the serum amino acid spectrum, with possible implications for the inflammatory process and organ function both in the pancreas and the gut. Supplementation of selected amino acids could possibly be of value in this severe condition.

The Influence of a load of L-arginine on serum amino acids and pancreatic apoptosis/proliferation and ATP levels in the rat

OBJECTIVES

Administration of high doses of amino acids like ethionine, methionine, and arginine causes pancreatic tissue damage. The initial mechanism behind these effects is not known. The aim of this study was to show the early effects of a load of L-arginine on programed cell death/proliferation and ATP levels in the pancreas.

METHODS

We analyzed in rats the effects of intraperitoneal administration of L-arginine on serum amino acids, pancreatic cell apoptosis/proliferation, and ATP levels at 8, 16, and 24 hours. Serum amino acid concentrations were measured with HPLC, tissue ATP was measured fluorometrically, apoptosis was studied with caspase-3 activity and histone-associated DNA-fragments, and proliferation was studied with thymidine autoradiography.

RESULTS

After a load of l-arginine, there were initially increased serum levels of L-arginine and L-citrulline, but these fell below control levels after 24 hours as well as amino acids in the glutamate family (ornithine, proline, histidine, and glutamine). Initially, increased ATP levels in the pancreatic tissue returned to control levels at 24 hours. The acinar cells proliferation was suppressed and the apoptosis rate strongly increased at 16 and 24 hours. Pancreatic histology showed vacuole formation in the acinar cells at 8 hours. At 16 hours, there was less vacuolization, but apoptotic bodies were seen, and at 24 hours there was cell degeneration but no necrosis.

CONCLUSIONS

After a load of l-arginine, amino acid metabolism causes a high ATP production in the pancreatic tissue that may cause mitochondrial initiation of cell death.