Microcirculatory dysfunction in acute pancreatitis. A new concept of pathogenesis involving vasomotion-associated arteriolar constriction and dilation

A Nationwide Analysis of Fluid Resuscitation Outcomes in Patients With Acute Pancreatitis

BACKGROUND

Traditionally, fluid resuscitation has been the foundation of effective acute pancreatitis (AP) treatment. Experts advocate for aggressive intravenous fluid (IVF) resuscitation, especially within the first 24 hours. Research suggests limited efficacy of this approach; in fact, some studies show there may be a risk of increased complications. The aim of this study was to assess outcomes of aggressive IVF resuscitation in patients with AP.

METHODS

We queried the TriNetX Research Network (Cambridge, Massachusetts, United States) for patients admitted between January 1, 2010, and December 31, 2020, with a diagnosis of AP and who had received IVF on admission for at least 24 hours. We compared two cohorts; cohort 1 consisted of patients receiving aggressive IVF resuscitation (>3 ml/kg/hr), and cohort 2 was comprised of patients receiving non-aggressive (≤1.5 ml/kg/hr) IVF resuscitation. We compared mortality during index hospitalization, hospital length of stay (HLS), mechanical ventilation rates, acute kidney injury (AKI), and severe sepsis between the cohorts with propensity scoring matched (PSM) pairs of patients. A sub-analysis of patients with severe AP was performed.

RESULTS

After comparing the two well-matched PSM cohorts (3,680/3,680), we found no significant differences in mortality, HLS, mechanical ventilation rates, AKI, or severe sepsis. We found similar results after conducting the sub-analysis of patients with severe pancreatitis.

CONCLUSIONS

We found no significant differences in mortality and HLS when comparing rates of IVF resuscitation.

Telomerase reverse transcriptase restores pancreatic microcirculation profiles and attenuates endothelial dysfunction by inhibiting mitochondrial superoxide production: A potential target for acute pancreatitis therapy

BACKGROUND

Acute pancreatitis (AP) is a potentially lethal disease related to prominent microcirculation dysfunction. Pancreatic microvascular endothelial dysfunction enhances oxidative stress with tissue damage. Increased superoxide production disrupts endothelial junction integrity and increases endothelial permeability. Endothelial mitochondrial ROS (mtROS) represent a major intracellular source of superoxide anions. The non-canonical function of telomerase reverse transcriptase (TERT) involves the maintenance of cellular redox homeostasis in somatic tissues.

METHODS

We investigated whether TERT restores microcirculation dysfunction and attenuates the endothelium injury by inhibiting superoxide production during AP progression. We established TERT transgenic and TERT knock-down mice and used cerulein (CER) and lipopolysaccharide (LPS) injections to induce AP models. In addition, we exposed HUVECs to LPS following TERT overexpression or silencing to explore the role of TERT in endothelial dysfunction. We also performed flow cytometry and confocal microscopy assays by using HUVECs. And a mtROS inhibitor, MitoTempo, was used to scavenge mitochondria superoxide and alkyl.

RESULTS

TERT transgenic mice were found to have restored pancreatic microcirculation profiles and microvascular endothelial morphology compared with wild-type mice under cerulein injection. In contrast, TERT silencing displayed the opposite effect in response to cerulein. Subsequently, we showed that TERT overexpression attenuates mtROS production and mitochondrial dysfunction during LPS-stimulated endothelial dysfunction. Furthermore, we found that TERT overexpression maintains the balance between mitochondrial contents and ATP level during endothelial dysfunction. In addition, the protective trend of MitoTempo is impeded after TERT silencing.

CONCLUSION

TERT restores pancreatic microcirculation dysfunction and attenuates microvascular endothelium lesions by inhibiting the increase of superoxide production and mitochondrial dysfunction.

Glucocorticoid Treatment in Acute Respiratory Distress Syndrome: An Overview on Mechanistic Insights and Clinical Benefit

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS), triggered by various pathogenic factors inside and outside the lungs, leads to diffuse lung injury and can result in respiratory failure and death, which are typical clinical critical emergencies. Severe acute pancreatitis (SAP), which has a poor clinical prognosis, is one of the most common diseases that induces ARDS. When SAP causes the body to produce a storm of inflammatory factors and even causes sepsis, clinicians will face a two-way choice between anti-inflammatory and anti-infection objectives while considering the damaged intestinal barrier and respiratory failure, which undoubtedly increases the difficulty of the diagnosis and treatment of SAP-ALI/ARDS. For a long time, many studies have been devoted to applying glucocorticoids (GCs) to control the inflammatory response and prevent and treat sepsis and ALI/ARDS. However, the specific mechanism is not precise, the clinical efficacy is uneven, and the corresponding side effects are endless. This review discusses the mechanism of action, current clinical application status, effectiveness assessment, and side effects of GCs in the treatment of ALI/ARDS (especially the subtype caused by SAP).

Heart Failure and Pancreas Exocrine Insufficiency: Pathophysiological Mechanisms and Clinical Point of View

Heart failure is associated with decreased tissue perfusion and increased venous congestion that may result in organ dysfunction. This dysfunction has been investigated extensively for many organs, but data regarding pancreatic (exocrine) dysfunction are scarce. In the present review we will discuss the available data on the mechanisms of pancreatic damage, how heart failure can lead to exocrine dysfunction, and its clinical consequences. We will show that heart failure causes significant impairment of pancreatic exocrine function, particularly in the elderly, which may exacerbate the clinical syndrome of heart failure. In addition, pancreatic exocrine insufficiency may lead to further deterioration of cardiovascular disease and heart failure, thus constituting a true vicious circle. We aim to provide insight into the pathophysiological mechanisms that constitute this reciprocal relation. Finally, novel treatment options for pancreatic dysfunction in heart failure are discussed.

Evaluation of Open Surgical and Endovascular Treatment Options for Visceral Artery Erosions after Pancreatitis and Pancreatic Surgery

Purpose: To report and compare the results of endovascular and open surgical treatment for erosion bleeding of visceral arteries following pancreatitis and pancreatic surgery. Materials and Methods: This retrospective study included 65 consecutive patients (46 males, mean age 63 ± 14 years) presenting with visceral artery erosions between January 2011 and December 2020. Endpoints were technical success, freedom from reintervention, stent-graft-related complications, and 30-day and one-year mortality. Results: The causes of erosion bleeding included complications of surgical treatment for the pancreas and upper gastrointestinal tract (75%), pancreatitis (19%), and spontaneous bleeding (6%). Pancreatectomy was performed in 34 (52%) patients, representing 2% of all pancreatectomy procedures (n = 1645) performed in our hospital during the study period. A total of 37 (57%) patients underwent endovascular treatment (EVT), and 28 (43%) patients had open surgery (OS) as a primary treatment. Eight of 37 (22%) patients in the EVT group underwent stent-graft treatment of the eroded vessels and 28 (78%) coil embolization. Six (9%) patients underwent reintervention with no significant differences between EVT and OS groups (11% vs. 7%, p = 0.692). Postoperative morbidity and complications in 52% of all patients were higher in the OS group than in the EVT group (41% vs. 68%, p = 0.029). The in-hospital 30-days mortality rate for all patients was 25%, and it was higher in the OS group than in the EVT group (14% vs. 39%, p = 0.017). Conclusions: An endovascular-first strategy for treating visceral arteries erosions may be preferred to reduce the complications associated with open surgery if patients are hemodynamically stable and have no anastomotic insufficiency. Endovascular treatment may be associated with better in-hospital survival when compared to primary open surgery. Further studies are required to identify the optimal approach.

Pretreatment with Warfarin Attenuates the Development of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats

In acute pancreatitis (AP), pancreatic damage leads to local vascular injury, manifesting as endothelial damage and activation, increased vascular permeability, leukocyte rolling, sticking and transmigration to pancreatic tissue as well as activation of coagulation. Previous studies have shown that pretreatment with heparin or acenocoumarol inhibits the development of AP. The aim of the present study was to check the impact of pretreatment with warfarin, an oral vitamin K antagonist, on the development of ischemia/reperfusion-induced AP in rats. AP was induced by pancreatic ischemia followed by reperfusion of the gland. Warfarin (90, 180 or 270 µg/kg/dose) or vehicle were administered intragastrically once a day for 7 days before induction of AP. The effect of warfarin on the severity of AP was assessed 6 h after pancreatic reperfusion. The assessment included histological, functional, and biochemical analyses. Pretreatment with warfarin given at a dose of 90 or 180 µg/kg/dose increased the international normalized ratio and reduced morphological signs of pancreatic damage such as pancreatic edema, vacuolization of acinar cells, necrosis and the number of hemorrhages. These effects were accompanied by an improvement of pancreatic blood flow and a decrease in serum level amylase, lipase, pro-inflammatory interleukin-1β and plasma level of D-dimer. In contrast, pretreatment with warfarin given at a dose of 270 µg/kg/dose led to an increase in severity of pancreatic damage and biochemical indicators of AP. In addition, this dose of warfarin resulted in deaths in some animals. Pretreatment with low doses of warfarin inhibits the development of AP induced by pancreatic ischemia followed by reperfusion.

Myrtus communis leaf extract protects against cerulein-induced acute pancreatitis in rats

In this study, the aim was to examine the potential protective effects of Myrtus communis subsp. communis leaf ethanol extract (MC) treatment against acute pancreatitis (AP) in rats. Thirty-two rats were grouped as the saline-pretreated control (C), MC-pretreated control (MC), saline-pretreated AP (AP), and MC-pretreated AP (MC + AP) groups. To induce AP, cerulein was administered (50 µg/kg) two times. The rats were given MC for 14 days before cerulein injection. Six hours after the final cerulein injection, the rats were sacrificed. Pancreatic damage was associated with an increase in the serum activity of lipase and amylase, the pancreatic activity of myeloperoxidase, and the pancreatic level of malondialdehyde, interleukin-1β, and interleukin-6. AP also led to a decrease in the pancreatic level of anti-inflammatory interleukin-10 and glutathione. Pretreatment with MC before the induction of AP significantly reduced the pancreatic damage observed during the histological examination as well as reversed the biochemical changes evoked by AP. PRACTICAL APPLICATIONS: Acute pancreatitis is characterized by high mortality (average about 5%; severe cases may reach about 30%). The current treatment for acute pancreatitis is mainly symptomatic. The introduction of herbal drugs may lead to the development of a new strategy in the treatment of this disease. This study revealed that MC reduced pancreatic injury by decreasing pro-inflammatory cytokines, increasing antioxidant capacity and anti-inflammatory cytokine, IL-10. To the authors' knowledge, this research is the first report showing that MC inhibits the development of AP. This observation suggests that MC may be useful in the prevention and the treatment of AP in clinical settings.

Statin use is not associated with an increased risk of acute pancreatitis-A meta-analysis of observational studies

Background

Statins are perceived as potential etiological factors for acute pancreatitis (AP), but recent evidence suggests the opposite. Our aim was to evaluate the association between statin use and risk of AP in observational studies.

Methods

Medline, Scopus, and Web of Science were searched for cohort (C) and case-control (CC) studies evaluating statins as intervention and AP as outcome. Pooled adjusted odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated.

Results

Thirteen studies (seven CC, six C) with 34,899 AP patients and 5,377,894 controls were included. Prevalence of statin use was 9.8% among AP patients and 25% among controls. Pooled adjusted OR was 1.00 (95% CI = 0.63 to 1.59) with considerable heterogeneity (I ²= 98%). CC studies were associated with increased AP risk (OR = 1.33; 95% CI = 1.20 to 1.47), unlike C studies (OR = 0.69; 95% CI = 0.37 to 1.31). No association with increased risk was found for studies from Western countries (OR = 0.90; 95% CI = 0.52 to 1.56), unlike for studies conducted in Asia (OR = 1.39; 95% CI = 1.10 to 1.75).

Conclusion

Statin use is not associated with increased risk of AP. Increased risk was limited to CC studies, which are more prone to bias, while C studies showed no global effect. Further research is needed to clarify whether statin type, dosage, treatment duration or AP etiology might account for this difference.

Higher Thrombin-Antithrombin III Complex Levels May Indicate Severe Acute Pancreatitis

AIM

Coagulation disorders may develop in association with severe acute pancreatitis (AP). Plasma thrombin-antithrombin III complex (TAT) levels are one of the principal markers of coagulation disorder. The purpose of this study was to evaluate TAT and other hemostatic parameters in patients with AP and to examine whether or not these parameters indicate the severity of AP.

METHOD

Forty-six patients with AP (14 severe, 32 non-severe) and a 30-member healthy control group were recruited. The severity of AP was determined using the revised Atlanta classification. ELISA was used to measure patients' plasma TAT levels.

RESULTS

The TAT levels of AP patients at presentation were higher than those of the control group (p = 0.005). The plasma TAT levels of patients with severe AP were also significantly higher than those of patients with non-severe AP (p = 0.05) and of the control group (p < 0.001). The general accuracy, sensitivity and specificity of TAT levels in predicting the severity of AP were 77.4, 77.8, and 77.3% respectively.

CONCLUSION

The coagulation cascade was activated in the AP patients in our study, and this was shown to become more pronounced as severity of the disease increased. Plasma TAT levels at the time of presentation in patients with AP can be used as a marker for predicting the severity of the disease.

Capsaicin-Sensitive Sensory Nerves Are Necessary for the Protective Effect of Ghrelin in Cerulein-Induced Acute Pancreatitis in Rats

Ghrelin was shown to exhibit protective and therapeutic effect in the gut. Aim of the study was to investigate the role of sensory nerves (SN) in the protective effect of ghrelin in acute pancreatitis (AP). Studies were performed on male Wistar rats or isolated pancreatic acinar cells. After capsaicin deactivation of sensory nerves (CDSN) or treatment with saline, rats were pretreated intraperitoneally with ghrelin or saline. In those rats, AP was induced by cerulein or pancreases were used for isolation of pancreatic acinar cells. Pancreatic acinar cells were incubated in cerulein-free or cerulein containing solution. In rats with intact SN, pretreatment with ghrelin led to a reversal of the cerulein-induced increase in pancreatic weight, plasma activity of lipase and plasma concentration of tumor necrosis factor-α (TNF-α). These effects were associated with an increase in plasma interleukin-4 concentration and reduction in histological signs of pancreatic damage. CDSN tended to increase the severity of AP and abolished the protective effect of ghrelin. Exposure of pancreatic acinar cells to cerulein led to increase in cellular expression of mRNA for TNF-α and cellular synthesis of this cytokine. Pretreatment with ghrelin reduced this alteration, but this effect was only observed in acinar cells obtained from rats with intact SN. Moreover, CDSN inhibited the cerulein- and ghrelin-induced increase in gene expression and synthesis of heat shock protein 70 (HSP70) in those cells. Ghrelin exhibits the protective effect in cerulein-induced AP on the organ and pancreatic acinar cell level. Sensory nerves ablation abolishes this effect.

SPATHOLOBUS SUBERECTUS STEM EXTRACT IMPROVES THE PROTECTIVE EFFECT OF HEPARIN ON CERULEIN-INDUCED PANCREATITIS

BACKGROUND

The present study evaluates the effect of Spatholobus suberectus stem extract (SS) in the management of pancreatitis alone and in combination with heparin.

MATERIAL AND METHODS

Pancreatitis was induced pancreatitis by cerulean (50μg/kg, i.p.) five times at an interval of 1 h without any pretreatment of drug. Rats were treated with SS (100 and 200 mg/kg, p. o.) and heparin (150 U/kg, i.p.) alone and in combination for the duration of a week. Later pancreatic weight and blood flow was estimated and different biochemical parameters like concentration of D-dimer and Interleukin 1β (IL-Ιβ) and activity of amylase and lipase were determined in blood of pancreatitis rats. Moreover effect of drug treatment on DNA synthesis and histopathology was also estimated on cerulean induced pancreatitis rats.

RESULT

Results of this study suggest that treatment with SS alone and in combination with heparin significantly increase in prothrombin time and pancreatic blood flow than negative control group. There was significant decrease in concentration of IL-Ιβ and D-dimer and activity of amylase and lipase in SS and heparin treated group than negative control group. Pancreatic DNA synthesis was also found to be reduced in SS and heparin alone and in combination treated group. Histopathology study also reveals that treatment with SS and heparin alone and in combination reduces edema, hemorrhages, leukocyte infiltration in the TS of pancreatic tissues.

CONCLUSION

Present study concludes that treatment with SS alone effectively manages the pancreatitis by ceasing the inflammatory pathway and potentiates the effect of heparin in the management of pancreatitis.

Therapeutic Effect of Low Doses of Acenocoumarol in the Course of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats

Intravascular activation of coagulation is observed in acute pancreatitis and is related to the severity of this inflammation. The aim of our study was to evaluate the impact of acenocoumarol therapy on the course of acute pancreatitis induced in male rats by pancreatic ischemia followed by reperfusion. Acenocoumarol at a dose of 50, 100, or 150 µg/kg/dose was administered intragastrically once a day, starting the first dose 24 h after the initiation of pancreatic reperfusion. Results: Histological examination showed that treatment with acenocoumarol reduces pancreatic edema, necrosis, and hemorrhages in rats with pancreatitis. Moreover, the administration of acenocoumarol decreased pancreatic inflammatory infiltration and vacuolization of pancreatic acinar cells. These findings were accompanied with a reduction in the serum activity of lipase and amylase, concentration of interleukin-1β, and plasma d-Dimer concentration. Moreover, the administration of acenocoumarol improved pancreatic blood flow and pancreatic DNA synthesis. Acenocoumarol given at a dose of 150 µg/kg/dose was the most effective in the treatment of early phase acute pancreatitis. However later, acenocoumarol given at the highest dose failed to exhibit any therapeutic effect; whereas lower doses of acenocoumarol were still effective in the treatment of acute pancreatitis. Conclusion: Treatment with acenocoumarol accelerates the recovery of ischemia/reperfusion-induced acute pancreatitis in rats.

The Interplay between Inflammation, Coagulation and Endothelial Injury in the Early Phase of Acute Pancreatitis: Clinical Implications

Acute pancreatitis (AP) is an inflammatory disease with varied severity, ranging from mild local inflammation to severe systemic involvement resulting in substantial mortality. Early pathologic events in AP, both local and systemic, are associated with vascular derangements, including endothelial activation and injury, dysregulation of vasomotor tone, increased vascular permeability, increased leukocyte migration to tissues, and activation of coagulation. The purpose of the review was to summarize current evidence regarding the interplay between inflammation, coagulation and endothelial dysfunction in the early phase of AP. Practical aspects were emphasized: (1) we summarized available data on diagnostic usefulness of the markers of endothelial dysfunction and activated coagulation in early prediction of severe AP; (2) we reviewed in detail the results of experimental studies and clinical trials targeting coagulation-inflammation interactions in severe AP. Among laboratory tests, d-dimer and angiopoietin-2 measurements seem the most useful in early prediction of severe AP. Although most clinical trials evaluating anticoagulants in treatment of severe AP did not show benefits, they also did not show significantly increased bleeding risk. Promising results of human trials were published for low molecular weight heparin treatment. Several anticoagulants that proved beneficial in animal experiments are thus worth testing in patients.

Protective Effect of Pretreatment with Acenocoumarol in Cerulein-Induced Acute Pancreatitis

Coagulation is recognized as a key player in inflammatory and autoimmune diseases. The aim of the current research was to examine the effect of pretreatment with acenocoumarol on the development of acute pancreatitis (AP) evoked by cerulein. Methods: AP was induced in rats by cerulein administered intraperitoneally. Acenocoumarol (50, 100 or 150 µg/kg/dose/day) or saline were given once daily for seven days before AP induction. Results: In rats with AP, pretreatment with acenocoumarol administered at the dose of 50 or 100 µg/kg/dose/day improved pancreatic histology, reducing the degree of edema and inflammatory infiltration, and vacuolization of acinar cells. Moreover, pretreatment with acenocoumarol given at the dose of 50 or 100 µg/kg/dose/day reduced the AP-evoked increase in pancreatic weight, serum activity of amylase and lipase, and serum concentration of pro-inflammatory interleukin-1β, as well as ameliorated pancreatic DNA synthesis and pancreatic blood flow. In contrast, acenocoumarol given at the dose of 150 μg/kg/dose did not exhibit any protective effect against cerulein-induced pancreatitis. Conclusion: Low doses of acenocoumarol, given before induction of AP by cerulein, inhibit the development of that inflammation.

Hemodynamic Variation and Intravenous Fluids Administered During ERCP and the Association With Post-ERCP Pancreatitis

OBJECTIVES

We sought to determine whether hypotension and the amount of intravenous (IV) fluids administered during endoscopic retrograde cholangiopancreatography (ERCP) were associated with post-ERCP pancreatitis.

METHODS

We identified patients who developed post-ERCP pancreatitis between 2009 and 2013. Using a case-control design, we extracted baseline and intra-ERCP vital signs and the amount of IV fluids given. We used regression to analyze the association between these factors and the risk of post-ERCP pancreatitis.

RESULTS

We found no association between intraprocedure hypotension (P = 0.17), bradycardia (P = 0.20), hypoxemia (P = 1.0), dehydration (P = 0.80), and post-ERCP pancreatitis. An increase in mean arterial pressure (MAP) more than 20 units from baseline (odds ratio [OR], 1.8; P = 0.03), increasing amount of IV fluids administered during ERCP (OR, 1.5; P = 0.03), female sex (OR, 2.6; P = 0.001), and younger age (OR, 1.02; P = 0.01) were associated with post-ERCP pancreatitis. In multivariate regression, female sex maintained statistical significance (P = 0.01); MAP more than 20 units from baseline (P = 0.1) and increased IV fluids (P = 0.09) showed an insignificant trend.

CONCLUSIONS

Hypotension during ERCP was not associated with post-ERCP pancreatitis. An increase in MAP more than 20 units from baseline and an increase in the amount of IV fluids administered during ERCP may increase the risk of post-ERCP pancreatitis.

The Effects of Pancreatic Microcirculatory Disturbances on Histopathologic Tissue Damage and the Outcome in Severe Acute Pancreatitis

OBJECTIVES

Severe acute pancreatitis is an inflammatory disease of the pancreas with a high morbidity and mortality. To date, no causal treatment is known. The aim of the present study was to analyze the impact of pancreatic microcirculatory disturbances in severe acute pancreatitis and to correlate the effects with histopathologic tissue damage and outcome.

METHODS

Severe acute pancreatitis was induced in 129 pigs by injection of glycodeoxycholic acid into the pancreatic duct. Pancreatic microcirculation, pancreatic tissue oxygenation, histopathologic tissue damage, and survival were measured and analyzed.

RESULTS

Our study demonstrates a strong correlation between pancreatic microcirculatory disturbances and histopathologic tissue damage (r = 0.728; P < 0.001). Furthermore, we showed a strong correlation between tissue oxygenation and the severity of the pancreatitis according to an established porcine pancreatitis score (r = 0.694; P < 0.001). In addition, disturbances of the pancreatic microcirculation were shown to be associated with an increased mortality rate in severe acute pancreatitis.

CONCLUSIONS

We found that pancreatic microcirculatory disturbances have significant effects on histopathologic tissue damage and the outcome of severe acute pancreatitis. For a better survival of severe acute pancreatitis, the treatment should focus on an improvement of pancreatic microcirculation.

PANCREATITIS OR NOT?--Elevated lipase and amylase in ICU patients

Elevation in serum levels of pancreatic enzymes (Hyperamylasemia and/or Hyperlipasemia) can occur in any Intensive Care Unit (ICU) patient either as a result of true acute pancreatitis (AP) or as a reflection of a non-pancreatic disease. Although most patients may not have clinical pancreatitis, identifying true acute pancreatitis in the ICU setting may be critical in the presence of associated co-morbid conditions of the disease for which the patient is being managed. With neither amylase nor lipase being specific for pancreatitis, it is important for the clinician to be aware of different causes of hyperamylasemia and hyperlipasemia, especially when clinical diagnosis of pancreatitis is unclear. This review will focus on understanding different non-pancreatic conditions where there is elevation of pancreatitis enzymes and to identify true acute pancreatitis in critically ill patients without typical symptoms.

Pretreatment with obestatin reduces the severity of ischemia/reperfusion-induced acute pancreatitis in rats

Obestatin, as ghrelin, has been originally extracted from the stomach, which remains its major source. Previous studies have shown that administration of obestatin exhibits protective and healing-promoting effects in several organs, including the stomach and kidney. In pancreas, pretreatment with obestatin inhibits the development of cerulein-induced acute pancreatitis and promotes survival of pancreatic beta cells and human islets. The aim of the present study was to check the universality of protective effect of obestatin in the pancreas. For this reason we investigated the influence of obestatin administration on the development of ischemia/reperfusion-induced pancreatitis. Acute pancreatitis was induced by pancreatic ischemia followed by reperfusion of the gland. Obestatin (4, 8 or 16 nmol/kg/dose) was administered intraperitoneally twice: 0.5h before exposure to ischemia, and 3h after the first injection. The effect of obestatin on the course of necrotizing pancreatitis was assessed after 6-h reperfusion, and included histological, functional, and biochemical analyses. Treatment with obestatin reduced morphological signs of pancreatic damage including edema, vacuolization of acinar cells, hemorrhages, acinar necrosis, and leukocyte infiltration of the gland. These effects were accompanied by an improvement of pancreatic DNA synthesis and superoxide dismutase activity, and a decrease in serum level of lipase and pro-inflammatory interleukin-1β. Moreover pretreatment with obestatin reduced myeloperoxidase activity and malondialdehyde concentration in pancreatic tissue of rats with acute pancreatitis.

CONCLUSIONS

Administration of obestatin inhibits the development of ischemia/reperfusion-induced acute pancreatitis. This observation, taken together with previous findings that obestatin protects the pancreas against cerulein-induced pancreatitis, indicates that protective effect of obestatin in the pancreas is universal and independent of the primary cause of acute pancreatitis.

An intensive care approach to posterior reversible encephalopathy syndrome (PRES): An analysis of 7 cases

OBJECTIVE

The aim of this study was to retrospectively evaluate the intensive care unit treatments applied to obstetrics patients with a diagnosis of posterior reversible encephalopathy syndrome (PRES).

MATERIAL AND METHODS

The cases of 7 pregnant patients who had been diagnosed with PRES between July 2011 and July 2013 were retrospectively reviewed. The patients' clinical data, brain magnetic resonance imaging (MRI) images before and after treatment, and neuropsychological tests were evaluated.

RESULTS

Five out of 7 patients had eclampsia, 1 patient had severe preeclampsia, and 1 patient developed HELLP syndrome secondary to PRES. Calcium channel blockers and β-blockers were used as antihypertensive treatment. All patients were treated with parenteral magnesium sulfate. In addition, sodium thiopental was given to control sedation and convulsions in all patients except 1. The neurological and radiological findings of all cases treated in the intensive care unit improved.

CONCLUSION

Posterior reversible encephalopathy syndrome is a clinical condition with a multifactorial etiology and can result in different clinical findings. Radiological imaging techniques can be used for the diagnosis of PRES. Pregnancy and the postpartum period often lead to this syndrome. In some cases, PRES can cause irreversible neurological deficits or death. For patients with severe radiological findings, early diagnosis and thiopental infusion, in addition to treatment with antihypertensive agents and magnesium sulfate, may lead to quicker and more effective recovery from clinical manifestations. We suggest supplementation of standard treatment with early thiopental infusion.

Acute alcohol-induced pancreatic injury is similar with intravenous and intragastric routes of alcohol administration

OBJECTIVES

Five percent of alcoholics develop an acute pancreatitis (AP). The mechanism leading to pancreatic injury is not yet understood. Microcirculatory disorders seem to play a pivotal role. The objective of this study was to compare alcoholic pancreatic injury in response to intravenous and intragastric routes of alcohol administration.

METHODS

Alcohol was applied in rats intravenously (IV) or gastric via a surgical implanted feeding tube (IG). Serum alcohol concentration was maintained between 1.5‰ and 2.5‰. Four subgroups (n = 6/group) were examined in the IV/IG arm and compared with healthy controls. Pancreatic microcirculation, enzyme levels, and morphological damage were assessed after 3, 6, 12, and 24 hours.

RESULTS

Microcirculatory analysis showed significantly disturbed pancreatic perfusion and increased adherent leukocytes in IV and IG animals. In IV and IG groups, serum amylase was increased without morphological signs of AP compared with healthy controls.

CONCLUSIONS

Alcohol application does not induce AP in rodents, but impairs pancreatic microcirculation irrespectively of the application route. Intravenous application is commonly used and shows no disadvantages compared with the physiological intragastric application form. Therefore, the intravenous route offers a valid model, which mimics the physiological process for further studies of the influence of acute alcohol intoxication on the pancreas.

Platelet activation in acute pancreatitis

OBJECTIVES

The aim of this study was to assess the functional state of platelets in patients with mild acute pancreatitis and severe acute pancreatitis (S-AP).

METHODS

The number of platelets and their morphological parameters were measured with Advia 2120. β-Thromboglobulin and platelet factor 4 concentrations were determined by enzyme-linked immunosorbent assay method. To evaluate the expression of platelet glycoproteins, flow cytometry method was used.

RESULTS

At the time of admission, a multiparameter evaluation of the platelets' function in AP patients showed enhanced platelet activation, which was reflected by an increase in the number of large platelets, concentration of degranulation markers (platelet factor 4 and β-thromboglobulin), expression of glycoprotein (Gp) IIb/IIIa, and decreased mean platelet component. Only in S-AP patients at day 1 a decreased number of platelets and high expression of P-selectin and GpIa were observed, which may suggest their prognostic value. At day 30, the procoagulation state was still present in S-AP patients, because of increased platelets and number of large platelets as well as high GpIIb/IIIa expression.

CONCLUSIONS

These results may indicate an important role of platelet activation in the pathogenesis of acute pancreatitis and the development of complications in S-AP.

Current controversies in fluid resuscitation in acute pancreatitis: a systematic review

Acute pancreatitis (AP) is a common inflammatory disorder of the pancreas resulting in considerable morbidity and mortality. Aggressive intravenous fluid resuscitation generally is recommended in all patients with AP and remains the cornerstone of management of these patients. However, the optimal rate, type, and the goal of resuscitation remain unclear. The purpose of this review was to give an insight about the pathophysiologic alterations in the pancreatic microcirculation that occur in AP, the markers for early recognition of severity of pancreatitis, the optimal fluid, and timing and extent of fluid resuscitation. An early elevated hematocrit, blood urea nitrogen, or creatinine should prompt clinicians to institute more intensive early resuscitation measures. Crystalloids are the currently recommended fluids for management of these patients. Current studies are underway to determine the optimal end points of fluid resuscitation that determine outcome.

Imaging of acute pancreatitis: update of the revised Atlanta classification

Acute pancreatitis is an acute inflammatory process of the pancreatic gland with increasing incidence worldwide. Usually the clinical presentation and course are mild, with an uneventful recovery. In 10% to 20% of patients, however, local and systemic complications develop, resulting in significant morbidity and mortality. In 1992, the Atlanta symposium provided definitions for acute pancreatitis and its severity. Insights into the pathophysiology of the disease, improved diagnostic imaging, and implementation of minimally invasive techniques have led to classification updates. This article reviews the cross-sectional imaging features of acute pancreatitis and presents proposed definitions of the revised Atlanta classification.

Antioxidant therapy in acute pancreatitis: experimental and clinical evidence

SIGNIFICANCE

Oxidative stress plays an important role in the pathogenesis of both acute and chronic pancreatitis. Although its impact is well investigated and has been studied clinically in chronic pancreatitis, it is less well defined for acute pancreatitis.

RECENT ADVANCES

Pathophysiological aspects of oxidative stress in acute pancreatitis have shown that reactive oxidative species (ROS) participate in the inflammatory cascade, and mediate inflammatory cell adhesion and consecutive tissue damage. Furthermore, ROS are involved in the generation of pain as another important clinical feature of patients suffering from acute pancreatitis.

CRITICAL ISSUES

Despite sufficient basic and experimental knowledge and evidence, the step from bench to bedside has not been successfully performed. Only a limited number of clinical studies are available that can give convincing evidence for the use of antioxidants in the clinical setting of acute pancreatitis.

FUTURE DIRECTIONS

Future studies are required to evaluate potential benefits of antioxidative substances to attenuate the severity of acute pancreatitis. Special focus should be put on the aspect of pain generation and the progression from mild to severe acute pancreatitis in the clinical setting.

Synergetic effect of yihuo qingyi decoction (see text) and recombinant staphylokinase in treatment of severe acute pancreatitis of rats

OBJECTIVE

To investigate the effect of recombinant staphylokinase (r-Sak) and the Chinese medicine Yihuo Qingyi Decoction ((see test) Herbal decoction for severe acute pancreatitis) in the treatment of the severe acute pancreatitis (SAP) in rats, and to observe the synergistic effect of the two.

METHODS

One hundred and sixty-two adult male SD rats with the body mass of 250-280 g were randomly divided into the following 5 groups: sham operation group (n = 18), control group (n = 36), Yihuo Qingyi Decoction treatment group (n = 36), r-Sak treatment group (n = 36), and Yihuo Qingyi Decoction plus r-Sak treatment group (n = 36). The SAP ratmodel was prepared by retrograde injection of 5% sodium taurocholate into the cholangiopancreatic duct. Two days before modeling, Yihuo Qingyi Decoction was intragastrically administrated, and r-Sak was intraperitoneally injected. The survival rate within 18 h after modeling was determined. The pancreatic blood flow, the weight of ascites, and the serum amylase and lipase were investigated at 6 h, 12 h, and 18kh after modeling, and the pancreatic tissue was examined under light microscopy to see its pathological change.

RESULTS

The 18 h survival count of group A, B, C, D and E rats was 9, 2, 6, 7 and 8 respectively. After r-Sak and Yihuo Qingyi Decoction intervention, the serum amylase and lipase and the weight of ascites were significantly decreased, especially in group E.18 h after modeling, the level of the serum amylase and lipase and the weight of ascites in group E was 1 100 +/- 118 U x L(-1), 1 000 +/- 150 U x L(-1) and 13.40 +/- 1.80 g respectively, obviously lower than that of group B (P < 0.05). After SAP was induced, the pancreatic blood flow showed a tendency to decrease, but the decrease extent in the treatment groups was smaller than that in the control group. 18h after modeling, the pancreatic blood flow in group B and group E was 30.16 +/- 8.96 mL x 100 g(-1) x min(-1), and 129.10 +/- 42.58 mL x 100 g(-1) x min respectively, there was significant difference (P < 0.05). The pathological change of the pancreatic tissue was alleviated in the treatment groups.

CONCLUSION

Both r-Sak and Yihuo Qingyi Decoction play a beneficial role in the treatment of rat SAP and there is a synergistic effect between the two.

Targeting P-selectin in acute pancreatitis

IMPORTANCE OF THE FIELD

Acute pancreatitis (AP) is a multifactorial disorder not fully understood yet. In particular, the pathogenetic pathways promoting a severe life-threatening course of AP are the subject of ongoing investigations. P-selectin has been shown to play a central role in the complex pathophysiology in AP as well as various other inflammatory conditions.

AREAS COVERED IN THIS REVIEW

P-selectin function in AP is reviewed with focus on its dual function as a mediator of leukocyte recruitment and cell adhesion, which implies the unique effect of linking both inflammation and coagulation, especially in the progression from mild to severe necrotizing AP. Potential therapeutic aspects are discussed with regard to the clinical situation.

WHAT THE READER WILL GAIN

A better understanding of the pathogenic role of P-selectin in AP and of the rationale for a therapeutic blockade.

TAKE HOME MESSAGE

P-selectin is a glycoprotein that mediates the adhesion of activated platelets and leukocytes to the vessel wall in various inflammatory conditions. Both pathophysiological steps are closely linked and play a key role in the course of severe AP. A treatment approach by inhibition of P-selectin could be of distinct interest as a therapeutic option in severe AP.

WITHDRAWN. Endoscopic retrograde cholangiopancreatography in gallstone-associated acute pancreatitis

BACKGROUND

Early endoscopic retrograde cholangio-pancreatography with or without endoscopic sphincterotomy (ERCP+/-ES) has been advocated to reduce complications in patients presenting with a severe attack of gallstone-associated acute pancreatitis (GAP). However, a recent trial has reported contradictory results. Importantly, patients with acute cholangitis were excluded suggesting it may be a major confounding factor affecting previous studies.

OBJECTIVES

To assess the effectiveness of early ERCP+/-ES compared to conservative management stratified according to severity of disease, concealment of randomisation, acute cholangitis and bilirubin level in the reduction of mortality, morbidity, length of hospitalisation and cost in adults suspected of having GAP.

SEARCH STRATEGY

We searched - Cochrane Library (Issue 4 2003), Medline (1966-2004), EMBASE (1980-2004) and LILACS. 'Grey literature' was sought by looking at cited references and hand searched to identify further relevant trials. Conference proceedings of United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology) were also hand searched.

SELECTION CRITERIA

Randomized controlled trials (RCT) of adult patients, from 15 years old or greater, presenting with gallstone-associated acute pancreatitis (GAP) comparing ERCP +/- ES versus Conservative management within 72 hours of admission.

DATA COLLECTION AND ANALYSIS

Data were assessed for quality independently by two reviewers. Wherever appropriate, results were pooled together and sub-grouped by predicted severity of disease. Fixed and random effects models were applied. Sensitivity analysis was performed to test the fragility of results.

MAIN RESULTS

Three trials, involving 511 patients, met inclusion criteria. The test for heterogeneity yielded statistically non-significant results (p-value 0.1 to 0.63) suggesting all comparisons were above the established threshold for combinability (p<0.1). Fixed effect and random effect meta-analyses gave identical results. Early ERCP +/- ES was associated with non-significant effect on reduction of mortality in predicted mild (OR = 0.62, 95% CI = 0.27 to 1.41) and severe GAP (OR = 0.62, 95% CI = 0.27 to 1.41). Reduction in complications was non-significant in predicted mild (OR = 0.89, 95% CI = 0.53 to 1.49), but significant in severe GAP (OR = 0.27, 95% CI = 0.14 to 0.53). There was insufficient evidence to draw any conclusions about hospital stay and cost.

AUTHORS' CONCLUSIONS

Odds of having complications are reduced in predicted severe disease by early ERCP +/- ES. This effect was however, non-significant in predicted mild disease and for reduction of mortality in either predicted mild or severe disease. These results are controlled for confounding due to associated acute cholangitis and are robust for clinical and statistical heterogeneity.

Therapeutic small-volume resuscitation preserves pancreatic microcirculation in acute experimental pancreatitis of graded severity in rats

BACKGROUND

Microcirculatory disorders play a major part in the pathogenesis of acute pancreatitis. Improvement of microcirculation is hypothesized to open a therapeutic window. The aim of this study was to evaluate the effects of small-volume resuscitation in acute pancreatitis.

METHODS

In rats, acute pancreatitis of graded severity was induced and pancreatic microcirculation was observed in vivo with an epiluminescent microscope. Primary outcome measures were microcirculation, leukocyte adherence, concentration of trypsinogen-activating peptide, amylase activity and histopathologic tissue damage.

RESULTS

In necrotizing pancreatitis patients receiving prophylactic intervention with 7.5% hypertonic saline the functional capillary density was 76%. Postcapillary venular leukocyte adherence was 45% of vein cross-section. The median histopathologic damage scored 8 points. In controls, a complete microcirculatory breakdown was observed, and in the group with therapeutic intervention no significant difference was detected. In intermediate pancreatitis, the number of perfused capillaries remained 55.0 versus 23.3% in controls. Leukocyte adherence was 40.0 versus 51.7%. The histopathologic damage scored 6.0 versus 9.0 points. Trypsinogen-activating peptide concentration was reduced to 164 versus 402 nM in controls. In cerulein pancreatitis, the number of perfused capillaries was equally preserved in both groups.

CONCLUSION

Small-volume resuscitation preserves capillary microcirculation and prevents pancreatic injury in intermediate necrotizing pancreatitis.

Capsaicin reduces tissue damage in experimental acute pancreatitis

OBJECTIVES

Calcitonin gene-related peptide (CGRP) is released from perivascular pancreatic nerves. It effects vasomotion and cytokine liberation in inflammatory processes, including acute pancreatitis (AP). Calcitonin gene-related peptide liberation is stimulated by capsaicin, a substance of red hot chili peppers. Aim of the study was to investigate the influence of exogenous capsaicin on experimental AP.

METHODS

Acute pancreatitis was induced in rats by glycodeoxycholic acid and cerulein. Animals were divided into 4 groups: (1) severe AP, (2) severe AP+capsaicin, (3) control without AP, and (4) control+capsaicin. After 24 hours, survival, histology, and CGRP were evaluated (n=6/group). In additional animals, erythrocyte flow and leukocyte activation were evaluated by intravital microscopy 6 hours after AP induction (n=6/group).

RESULTS

In the control groups, all animals survived without histological alterations. Mortality in severe AP was 67%. Capsaicin reduced mortality to 16% (P<0.05). Acute pancreatitis animals developed pancreatic inflammation and necrosis, which was significantly less after capsaicin application. Intravital microscopy in severe AP showed reduced erythrocyte velocity and increased leukocyte adhesion, which was nearly normalized by capsaicin (P<0.01). Calcitonin gene-related peptide increased in both capsaicin groups, indicating endogenous CGRP liberation (P<0.01).

CONCLUSION

Capsaicin releases endogenous CGRP with improved pancreatic microcirculation and reduced inflammation in experimental AP. This underlines neuropeptide activity in the pathogenesis of AP.

P-selectin inhibition reduces severity of acute experimental pancreatitis

BACKGROUND

Acute pancreatitis (AP) is characterized by disturbed pancreatic microcirculation with tissue necrosis. Platelet and leukocyte activation contributes to microcirculatory disorders and inflammatory tissue infiltration. P-selectin mediates the adhesion of both activated platelets and leukocytes to the vessel wall. The aim of this study was to investigate the effect of P-selectin inhibition by monoclonal antibodies (AB) on experimental AP.

METHODS

AP was induced in rats by glycodeoxycholic acid (GDOC) intraductally and by cerulein infusion. Animals were divided into 4 groups: (1) severe AP (GDOC); (2) severe AP + platelet inhibition (GDOC + selectin AB); (3) control (Ringer); (4) control + platelet inhibition (Ringer + selectin AB). 24 h after AP induction, histology and serum (amylase, thromboxane A2) were evaluated (6 animals per group). In additional 12 animals of each group, platelet and leukocyte activation as well as erythrocyte flow patterns were evaluated by intravital microscopy 12 h after AP induction.

RESULTS

AP induction caused significant tissue inflammation and necrosis with increased amylase and thromboxane levels. Prophylactic inhibition of P-selectin reduced tissue inflammation and necrosis significantly. Severe AP led to significantly more adherent platelets and leukocytes in capillaries and venules. In contrast, antibody-treated animals showed significantly reduced platelet-endothelium interaction compared with untreated AP animals. Antibody application in control animals without AP did not induce any changes compared with healthy control animals.

CONCLUSION

Inhibition of P-selectin reduces tissue damage in experimental AP. This is associated with a reduction in platelet- and leukocyte-endothelium interaction and an improvement in pancreatic microcirculation.

Early rise in inflammation and microcirculatory disorder determine the development of autoimmune pancreatitis in the MRL/Mp-mouse

Autoimmune pancreatitis (AIP) is a rare cause of chronic pancreatitis and mimics pancreatic cancer. Although there is strong interest in research, etiology and pathophysiology of AIP are still unknown. Therefore, we analyzed a total of 92 MRL/Mp-mice of either sex, which are prone to develop AIP, in four different age groups (8-12, 16-20, 24-28, and 32-40 wk). Using intravital fluorescence microscopy, histology, laboratory analysis, and Western blot, onset, severity, and pathophysiological mechanisms of AIP were evaluated. Female animals showed in vivo an age-dependent increase of intrapancreatic leukocyte accumulation, as well as a loss in functional capillary perfusion. In contrast, intrapancreatic inflammation in male mice was less pronounced and not age dependent. Furthermore, pancreatic tissue specimen of female animals exhibited major organ destruction with significantly higher values of mean pathological scores (1.5 +/- 0.3 vs. < or =0.2; P < 0.05), as well as significantly increased CD4-, CD8-, CD11b-, and CD138-positive cells compared with male animals of the same age. Interestingly, there was a significant positive correlation between intravascular leukocyte adherence and the histopathological score of the pancreas, indicating a determining role of the innate immune system for the late onset of AIP. The present study shows that the onset of AIP is characterized by an inflammatory response and microcirculatory failure, most probably constituting initiators and propagators of this autoimmune disease.

Nutritive perfusion of pancreatic endocrine tissue during hemorrhagic hypotension: how differ islets in situ from islet isografts?

Although the exocrine gland frequently has I/R-associated complications such as posttransplant pancreatitis, hypoxia-induced dysfunction of pancreatic endocrine tissue is rarely observed. However, sympathetic hypersensitivity is accused of impaired endocrine function observed in human pancreatic grafts. These tissue-confined differences in susceptibility might be attributed to a distinct islet-specific regulatory control of blood flow (BF). To investigate this hypothesis, intravital microscopy was used for visualization of islets in situ and revascularized islet isografts in Syrian golden hamsters. Blood withdrawal was performed to induce sympathetic stimulation and to evoke an appropriate stress response of the tissue under investigation. Hypotension resulted in a perfusion pressure-dependent reduction of perfusion in both islets in situ and islet isografts. This was associated with comparable microhemodynamics of the tissues in direct vicinity, that is, pancreatic exocrine and host muscle tissue. There was a progressive decrease in functional capillary density of islets in situ and islet isografts that significantly correlated with the stepwise reduction of arterial blood pressure and did not differ in the hypotension-induced perfusion pattern in the neighboring exocrine and host skeletal muscle tissue. Concomitantly, capillary BF in islets in situ and islet isografts and in pancreatic exocrine and host muscle tissue was found to be reduced due to hypotension-associated decreases in capillary diameters and BF velocity. Microvascular perfusion of pancreatic islets and islet isografts is not preserved but strongly parallels perfusion pattern of the neighboring tissue under hemorrhagic stress. This disproves the existence of an individual islet-specific regulatory control of blood flow.

Fluid resuscitation in acute pancreatitis

Acute pancreatitis is a common inflammatory disorder of the pancreas resulting in considerable morbidity and a mortality rate of approximately 5%. Although there are no pharmacologic treatments known to improve important outcomes, aggressive intravenous fluid resuscitation generally is recommended in all patients. However, few human investigations have been performed and several important questions have not been answered. For example, what is the optimal resuscitative fluid? Is there a role for colloid solutions? To what clinical marker should resuscitation be targeted? When is the best time to start such fluids and in which group of patients? This review describes the microcirculation of the pancreas and the pathophysiologic alterations caused by acute pancreatitis. Previous animal experiments are described, as are the limited human studies specifically addressing fluid resuscitation. Finally, current recommendations and goals for further investigation are highlighted. It is our hope that this review will stimulate interest in this often overlooked subject and lead to carefully designed human clinical trials using varying fluid solutions and rates, with an emphasis on patient monitoring and safety, in the near future.

Ischemic acute pancreatitis: clinical features of 11 patients and review of the literature

BACKGROUND

Besides alcohol and gallstones, pancreatic ischemia can cause acute pancreatitis (AP). This entity should be considered when no other reasons can be defined. The aim of the current study was to define ischemic AP with its pathophysiologic, radiologic, and clinical conditions.

METHODS

Eleven patients with ischemic AP of different origin were analyzed regarding course, severity, and outcome, as well as diagnostic and therapeutic measures.

RESULTS

Ischemic AP was caused by hemorrhage and hypotension (7 patients) or mesenteric macrovessel occlusion (4 patients). Therapy was conservative (4 patients) or operative with hemostasis, necrosectomy, and drainage (7 patients). Seven patients died within 38 days, and 4 patients recovered.

CONCLUSION

Pancreatic hypoperfusion is an important etiology of AP. Severity of the disease ranges from moderate reversible changes to severe courses with fatal outcome. The indication for surgical intervention in ischemic AP is more aggressive; diagnostic and conservative therapeutic procedures are similar to AP of other etiologies.

Protective role of heme oxygenase-1 in pancreatic microcirculatory dysfunction after ischemia/reperfusion in rats

OBJECTIVES

Microcirculatory derangements caused by ischemia and reperfusion (I/R) play a pivotal role in acute and graft pancreatitis. The inducible enzyme heme oxygenase 1 (HO-1) has been shown to decrease I/R injury by modulation of capillary perfusion in other organs. It was the aim of this study to evaluate the effect of HO-1 induction on pancreatic microcirculation after I/R.

METHODS

Rats were randomized into 4 groups: (1) sham controls; (2) 1-hour ischemia and 2-hour reperfusion (I/R); (3) I/R + cobalt protoporphyrin (CoPP), an HO-1 inducer; and (4) I/R + CoPP + tin protoporphyrin, an HO inhibitor. Functional capillary density (FCD) and leukocyte endothelium interaction were analyzed using intravital microscopy during reperfusion. Expression of HO-1 mRNA, HO-1 protein, and HO activity were assessed by Northern blot, Western blot, and an HO activity assay.

RESULTS

Functional capillary density decreased significantly in the I/R group as compared with sham controls. Cobalt protoporphyrin treatment increased FCD to control values. In contrast, HO inhibition in CoPP-pretreated animals lowered FCD and increased leukocyte endothelium interaction significantly. Cobalt protoporphyrin administration increased HO-1 mRNA, protein, and HO activity, whereas activity of the enzyme was reduced after injection of tin protoporphyrin.

CONCLUSIONS

Heme oxygenase 1 plays a beneficial role in pancreatic microcirculatory derangements after I/R. This could be of therapeutic relevance after pancreas transplantation and other forms of postischemic pancreatitis.

Retroperitoneal compartment pressure elevation impairs pancreatic tissue blood flow

OBJECTIVES

To investigate whether the increase of the retroperitoneal compartment pressure, as in the case of peripancreatic fluid accumulation in severe acute pancreatitis, simulated by infusing a colloid fluid into the retroperitoneum, has any effect on pancreatic tissue blood flow.

METHODS

Six male anesthetized swine were subjected to a transcutaneous placement of catheters into the retroperitoneal space. Through these catheters, a colloid solution was infused, under continuous retroperitoneal pressure monitoring, to achieve a pressure up to 20 mm Hg. Pancreatic tissue blood flow was assessed by colored microsphere injection technique, and pancreatic interstitial pressure was measured by means of a commercially available pressure monitor system before and after the distension of the retroperitoneal space, allowing the appropriate time for the animals to be stabilized from any intervention.

RESULTS

The increase in the retroperitoneal compartment pressure was found to significantly increase pancreatic interstitial pressure (from 8 +/- 1 to 20 +/- 2.4 mm Hg, P = 0.001) as well as reduce pancreatic tissue blood flow (from 1.75 +/- 0.4 to 0.56 +/- 0.12 mL . min . g, P = 0.002).

CONCLUSIONS

The increase of retroperitoneal pressure leads to an impairment of pancreatic tissue blood flow in the healthy pancreas. Although these findings support the hypothesis that peripancreatic fluid collection during the course of acute pancreatitis could contribute or augment pancreatic tissue ischemia, further assessment is necessary.

Platelet function in acute experimental pancreatitis

Acute pancreatitis (AP) is characterized by disturbances of pancreatic microcirculation. It remains unclear whether platelets contribute to these perfusion disturbances. The aim of our study was to investigate platelet activation and function in experimental AP. Acute pancreatitis was induced in rats: (1) control (n=18; Ringer's solution), (2) mild AP (n=18; cerulein), and (3) severe AP (n=18; glycodeoxycholic acid (GDOC)+cerulein). After 12 h, intravital microscopy was performed. Rhodamine-stained platelets were used to investigate velocity and endothelial adhesion in capillaries and venules. In addition, erythrocyte velocity and leukocyte adhesion were evaluated. Serum amylase, thromboxane A2, and histology were evaluated after 24 h in additional animals of each group. Results showed that 24 h after cerulein application, histology exhibited a mild AP, whereas GDOC induced severe necrotizing AP. Intravital microscopy showed significantly more platelet-endothelium interaction, reduced erythrocyte velocity, and increased leukocyte adherence in animals with AP compared to control animals. Thromboxane levels were significantly elevated in all AP animals and correlated with the extent of platelet activation and severity of AP. In conclusion, platelet activation plays an important role in acute, especially necrotizing, pancreatitis. Mainly temporary platelet-endothelium interaction is observed during mild AP, whereas severe AP is characterized by firm adhesion with consecutive coagulatory activation and perfusion failure.

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Role of growth hormone and insulin-like growth factor-1 in the protective effect of ghrelin in ischemia/reperfusion-induced acute pancreatitis

Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, has been shown to exhibit gastroprotective properties. The aim of present study was to determine whether ghrelin administration protects the pancreas against ischemia/reperfusion-induced pancreatitis and, if so, what is the role of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in this effect. In sham-operated or hypophysectomized rats, acute pancreatitis was induced by pancreatic ischemia followed by reperfusion. Ghrelin (4, 8 or 16 nmol/kg/dose) or IGF-1 (20 nmol/kg/dose) were administered intraperitoneally twice before and during induction of acute pancreatitis. In pituitary-intact rats, treatment with ghrelin attenuated the development of ischemia/reperfusion-induced pancreatitis and this effect was associated with partial reversion of the pancreatitis-evoked decrease in serum concentration of GH and IGF-1. Hypophysectomy eliminated GH from the serum, reduced serum IGF-1 concentration by 90% and increased in the severity of ischemia/reperfusion-induced pancreatitis. Administration of ghrelin was without any beneficial effect in this group of rats. In contrast, administration of IGF-1 in hypophysectomized rats reduced the severity of ischemia/reperfusion-induced pancreatitis in hypophysectomized rats. We conclude that administration of ghrelin inhibits the development of ischemia/reperfusion-induced pancreatitis and this effect is mediated by its influence on the release of GH and IGF-1.

Potential effects of hyperbaric oxygen therapy in acute pancreatitis

BACKGROUND

To extract from the biomedical published reports, the effects of hyperbaric oxygen (HBO) on inflammatory disease, in particular acute pancreatitis.

METHODS

This review will explain these effects and evaluate potential mechanisms of action of HBO in acute pancreatitis. A Medline/PubMed search (January 1966 to July 2004) with manual cross-referencing was conducted, including all relevant articles investigating the molecular and systemic effects of HBO on inflammatory diseases, particularly focusing on the studies of acute pancreatitis. All publication types, languages and subsets were searched.

RESULTS

Original and review articles and short communications were extracted. The selected original articles covered the molecular and systemic effects of HBO and the effects in inflammatory disease states. The major findings are that HBO can act as an anti-inflammatory agent and as an antimicrobial agent. Many of the effects of HBO would be beneficial in the treatment of acute severe pancreatitis. Work carried out to date in animal models of acute pancreatitis shows promising improvements in severity but studies are limited to date.

CONCLUSION

Acute pancreatitis impairs the pancreatic and systemic microcirculation and causes acute inflammation. These processes are potentially improved by HBO therapy.

Tetrahydrobiopterin attenuates microvascular reperfusion injury following murine pancreas transplantation

In this study we investigated the effect of tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthases, on ischemia-reperfusion injury (IRI) following murine pancreas transplantation. Pancreatic grafts were exposed to prolonged cold ischemia times (CIT) and different treatment regimens: normal saline (S), S + 16 h CIT, BH4 50 mg/kg + 16 h CIT. Nontransplanted animals served as controls. Graft microcirculation was analyzed by means of functional capillary density (FCD) and capillary diameters (CD) after 2 h reperfusion using intravital microscopy. Quantification of inflammatory responses (mononuclear infiltration) and endothelial disintegration (edema formation) was done by histology (hematoxylin and eosin), and peroxynitrite formation assessed by nitrotyrosine immunostaining. FCD was significantly reduced after prolonged CIT, paralleled by increased peroxynitrite formation as compared with controls (all p < 0.05). Microcirculatory changes correlated significantly with intragraft peroxynitrite generation (Spearman: r = -0.56; p < 0.01). Pancreatic grafts treated with BH4 displayed markedly higher FCD values (p < 0.01) and abrogated nitrotyrosine staining (p = 0.03). CD were not significantly different in any group. Histology showed increased inflammation, interstitial edema, hemorrhage, acinar vacuolization and focal areas of necrosis after 16 h CIT, which was diminished by BH4 administration (p < 0.01). BH4 treatment significantly reduces post-ischemic deterioration of microcirculation as well as histologic damage and might be a promising novel strategy in attenuating IRI following pancreas transplantation.

Disturbances of the microcirculation in acute pancreatitis

BACKGROUND

Severe acute pancreatitis is characterized by pancreatic necrosis, resulting in local and systemic inflammation. Pancreatitis affects both the systemic and pancreatic vasculature. This review focuses on the underlying processes involved in the changes of microvascular anatomy following acute pancreatitis.

METHODS

A Medline/PubMed search (January 1966 to December 2005) with manual cross-referencing was conducted. All relevant articles investigating the pancreatic microcirculatory anatomy and the effect of pancreatitis on the microcirculation were included.

RESULTS

The pancreas is susceptible to ischaemic insult, which can exacerbate acute pancreatitis. There is also increasing evidence of pancreatic and systemic microvascular disturbances in the pathogenesis of pancreatitis, including vasoconstriction, shunting, inadequate perfusion, and increased blood viscosity and coagulation. These processes may be caused or exacerbated by ischaemia-reperfusion injury and the development of oxygen-derived free radicals.

CONCLUSION

Acute pancreatitis impairs the pancreatic and systemic microcirculation, which is a key pathological process in the development of severe necrotizing disease.

Vascular complications of pancreatitis

Vascular complications of pancreatitis are a major cause of morbidity and mortality. Arterial complications include haemorrhage from direct arterial erosion or pseudoaneurysm formation, and visceral ischaemia. Venous complications predominantly are related to splanchnic vein thrombosis. This review, with illustrative cases, describes the main manifestations of these complications and emphasizes the importance of early radiological diagnosis and intervention.

Fluid resuscitation and nutritional support during severe acute pancreatitis in the past: what have we learned and how can we do better?

BACKGROUND/AIMS

Severe acute pancreatitis is associated with microcirculatory impairment, increased gut permeability and metabolic changes. The aim of the present study was to evaluate initial fluid resuscitation and nutritional support versus outcome in patients with severe acute pancreatitis.

METHODS

All cases of acute pancreatitis admitted 1994-2003 were analyzed retrospectively. The inclusion criteria of severe acute pancreatitis were organ failure and/or local complications according to the Atlanta classification system. Mortality was used as outcome measure.

RESULTS

Ninty-nine patients were included in the study. The hospital mortality was 17%. Hypovolemia at arrival was found in 13% (13/99) and correlated with increased hospital mortality (P=0.009). During the first three days in average 11000+/-4100 ml of fluids and 1470+/-820 calories were administered. Total parental nutrition was given to 73% (69/95) and enteral nutrition served as a complement in 29% (28/95) of the patients. Hyperglycemia was seen in 61% (55/90) of the patients and insulin was administered to 53% (29/55) at an average glucose level of 19+/-3 mmol/l. The intake of oral food was reintroduced in average 15+/-9 days after admission and was interrupted in 17% (13/75) because of pain relapse.

CONCLUSION

A nutritional treatment regime in severe acute pancreatitis including a moderate and hypocaloric initial fluid resuscitation, parental nutrition as the preferred route for nutritional support and a non-strict glucose control, with an associated mortality of 17%, indicates several modes of improving outcome.

In vivo characterization of developing chronic pancreatitis in rats

Despite numerous experimental and clinical investigations, there is no unifying concept on pathophysiology and pathogenesis of chronic pancreatitis. Defining the interplay between pancreatic microcirculation and parenchymal tissue, we will provide a basis for the better understanding of pancreatic fibrogenesis using in vivo high-resolution multifluorescence microscopy in dibutyltin chloride (DBTC)-exposed rats. Pancreatic microcirculation at days 3 and 7 after DBTC revealed leukocyte activation with a two-fold higher fraction of rolling cells and a nine- to 10-fold increase of cells firmly adherent to the endothelial lining, followed by subsequent transendothelial migration into tissue, as given by chloracetate esterase histology. In vivo staining of acinar tissue with bisbenzimide presented single cells exhibiting nuclear chromatin condensation and fragmentation. Apoptotic cell death was confirmed by immunohistochemical staining for active caspase-3 as well as by TUNEL analysis. Necrotic cells were found dispersed throughout the exocrine tissue under observation. Both modes of cell death were found highest in extent at days 3 and 7 with 15-20 cells/mm2, but progressively decreased below 10 cells/mm2 up to 28 days after DBTC. By means of in vivo microscopy yellow-green autofluorescent collagen deposits were found at day 7 and progressively increased up to approximately 12% at day 28 after DBTC. Concomitantly, density of capillaries progressively decreased and capillaries failing to conduct blood flow became apparent. Present on-line analysis indicates an early inflammatory response with acinar cell death, most probably triggering progression of disease with collagen deposition, capillary rarefication and manifestation of perfusion failure. These temporal and spatial multiparameter measurements of the in vivo microenvironment provide new insights into the pathological processes of pancreatic fibrogenesis.