Influencing factors of pancreatic microcirculatory impairment in acute panceatitis

Overexpression of Plakophilin2 Mitigates Capillary Leak Syndrome in Severe Acute Pancreatitis by Activating the p38/MAPK Signaling Pathway

Purpose

Capillary leak syndrome (CLS) is an intermediary phase between severe acute pancreatitis (SAP) and multiple organ failure. As a result, CLS is of clinical importance for enhancing the prognosis of SAP. Plakophilin2 (PKP2), an essential constituent of desmosomes, plays a critical role in promoting connections between epithelial cells. However, the function and mechanism of PKP2 in CLS in SAP are not clear at present.

Methods

We detected the expression of PKP2 in mice pancreatic tissue by transcriptome sequencing and bioinformatics analysis. PKP2 was overexpressed and knocked down to assess its influence on cell permeability, the cytoskeleton, tight junction molecules, cell adhesion junction molecules, and associated pathways.

Results

PKP2 expression was increased in the pancreatic tissues of SAP mice and human umbilical vein endothelial cells (HUVECs) after lipopolysaccharide (LPS) stimulation. PKP2 overexpression not only reduced endothelial cell permeability but also improved cytoskeleton relaxation in response to acute inflammatory stimulation. PKP2 overexpression increased levels of ZO-1, occludin, claudin1, β-catenin, and connexin43. The overexpression of PKP2 in LPS-induced HUVECs counteracted the inhibitory effect of SB203580 (a p38/MAPK signaling pathway inhibitor) on the p38/MAPK signaling pathway, thereby restoring the levels of ZO-1, β-catenin, and claudin1. Additionally, PKP2 suppression eliminated the enhanced levels of ZO-1, β-catenin, occludin, and claudin1 induced by dehydrocorydaline. We predicted that the upstream transcription factor PPARγregulates PKP2 expression, and our findings demonstrate that the PPARγactivator rosiglitazone significantly upregulates PKP2, whereas its antagonist GW9662 down-regulates PKP2. Administration of rosiglitazone significantly reduced the increase in HUVECs permeability stimulated by LPS. Conversely, PKP2 overexpression counteracted the GW9662-induced reduction in ZO-1, phosphorylated p38/p38, and claudin1.

Conclusion

The activation of the p38/MAPK signaling pathway by PKP2 mitigates CLS in SAP. PPARγactivator rosiglitazone can up-regulate PKP2. Overall, directing efforts toward PKP2 could prove to be a feasible treatment approach for effectively managing CLS in SAP.

Venous Thrombosis in Acute Pancreatitis: What to and Not to Do?

Acute pancreatitis is an acute inflammatory condition of the pancreas that has not only local but systemic effects as well. Venous thrombosis is one such complication which can give rise to thrombosis of the peripheral vasculature in the form of deep vein thrombosis, pulmonary embolism, and splanchnic vein thrombosis. The prevalence of these complications increases with the severity of the disease and adds to the adverse outcomes profile. With better imaging and awareness, more cases are being detected, although many at times it can be an incidental finding. However, it remains understudied and strangely, most of the guidelines on the management of acute pancreatitis are silent on this aspect. This review offers an overview of the incidence, pathophysiology, symptomatology, diagnostic work-up, and management of venous thrombosis that develops in AP.

Hemorheological and Microcirculatory Relations of Acute Pancreatitis

Acute pancreatitis still means a serious challenge in clinical practice. Its pathomechanism is complex and has yet to be fully elucidated. Rheological properties of blood play an important role in tissue perfusion and show non-specific changes in acute pancreatitis. An increase in blood and plasma viscosity, impairment of red blood cell deformability, and enhanced red blood cell aggregation caused by metabolic, inflammatory, free radical-related changes and mechanical stress contribute to the deterioration of the blood flow in the large vessels and also in the microcirculation. Revealing the significance of these changes in acute pancreatitis may better explain the pathogenesis and optimize the therapy. In this review, we give an overview of the role of impaired microcirculation by changes in hemorheological properties in acute pancreatitis.

Research Progress of Antioxidant Nanomaterials for Acute Pancreatitis

Acute pancreatitis (AP) is a complex inflammatory disease caused by multiple etiologies, the pathogenesis of which has not been fully elucidated. Oxidative stress is important for the regulation of inflammation-related signaling pathways, the recruitment of inflammatory cells, the release of inflammatory factors, and other processes, and plays a key role in the occurrence and development of AP. In recent years, antioxidant therapy that suppresses oxidative stress by scavenging reactive oxygen species has become a research highlight of AP. However, traditional antioxidant drugs have problems such as poor drug stability and low delivery efficiency, which limit their clinical translation and applications. Nanomaterials bring a brand-new opportunity for the antioxidant treatment of AP. This review focuses on the multiple advantages of nanomaterials, including small size, good stability, high permeability, and long retention effect, which can be used not only as effective carriers of traditional antioxidant drugs but also directly as antioxidants. In this review, after first discussing the association between oxidative stress and AP, we focused on summarizing the literature related to antioxidant nanomaterials for the treatment of AP and highlighting the effects of these nanomaterials on the indicators related to oxidative stress in pathological states, aiming to provide references for follow-up research and promote clinical application.

Pancreatic ductal anatomy: more than meets the eye

PURPOSE

Anatomical variations of the pancreas are relatively frequent and often understudied. The ductal system of the pancreas has multiple variations, which are not frequently reported in the literature.

MATERIALS AND METHODS

The anatomy of the pancreas was studied through macroscopic anatomical dissection on 50 organ complexes (the pancreas, spleen, and duodenum) donated to the department of human anatomy, from patients, who died of causes not related to pancreatic diseases.

RESULTS

In type I, the main pancreatic duct (Wirsung's duct, MPD) and the accessory pancreatic duct (Santorini's duct, APD) were merged but most of the head was drained by the MPD (10% of cases). In type II, the MPD and APD were merged but most of the head was drained by the APD (4% of cases). In type III, the APD was absent and the head was drained by the MPD (14% of cases). In type IV, there was an inverted pancreas divisum where the ducts did not merge but each drained a part of the head (6% of cases). Classical pancreas divisum where the ducts did not merge but each drained a part of the head was considered as type V (4% of cases). In type VI, the MPD and APD merged and each drained a part of the head (48% of cases). In type VII, the MPD and APD merged but the upper part of the head was drained by the main pancreatic duct (4% of cases). In type VIII, the MPD and APD merged but the lower part of the head was drained by the main pancreatic duct (4% of cases). In the IX type, the MPD and APD merged but the head was drained by the branches of the MPD (6% of cases).

CONCLUSIONS

There are several drainage patterns of the pancreas. In some cases, one of the ducts provides more drainage of the gland than the other. This is clinically relevant since blockage of the main source of drainage leads to pancreatic juice stasis. It also explains cases when partial or total blockage of the duct results in the pancreatitis of an isolated zone.

Is hyperlipazemia a poor prognostic factor in patients with COVID-19 ?

Introduction: COVID-19 disease may pose a considerable health threat to healthy individuals and individuals with comorbidity. The SARS-CoV-2 virus affects the respiratory tract and may cause damage to the pancreas by binding to the ACE-2 receptor in the pancreas. In our study, we investigated the effects of hyperlipasemia on morbidity and mortality in patients diagnosed with COVID-19. Material and Method: In this study, 2350 patients diagnosed with COVID-19 between November 2020 and December 2020 were retrospectively reviewed. Other possible causes of hyperlipasemia were excluded. Hyperlipasemia secondary to COVID-19 was detected in 338 patients. These patients were divided into two groups based on their lipase elevation rates. Results: Hyperlipasemia was detected in 14.4% of the patients diagnosed with COVID-19, and severe hyperlipasemia (>3x) was detected in 2.3%. The mean age of the patients was 64±13.8 (18-92), of which 59.5% (201) were male. In our study, 24 patients (1%) were diagnosed with acute pancreatitis. When compared according to lipase level, a significant difference was found between the groups regarding the history of HT, CCI score, development of ARF at follow-up, development of ARDS, need for ICU hospitalization, need for intubation, length of stay in ICU, and death rates. A weak correlation was found in the correlation analysis between hyperlipasemia and ARDS development and mortality. Conclusion: Elevated lipase levels were associated with poor prognosis and mortality in patients with COVID-19 infection.

Treatment of Microcirculatory Disturbances in Acute Pancreatitis: Where Are We Now?

Acute pancreatitis is a serious inflammatory condition. Research has shown an increase in the number of pancreatitis-associated hospitalizations, with a marked decline in the mortality rates down to 0.79% in patients with acute pancreatitis and 0.26% in patients with exacerbation of chronic pancreatitis. Up to one-third of patients develop pancreatic tissue necrosis, with a mortality rate of 30%. One of the mechanisms is the disturbances in pancreatic microcirculation due to the release of endothelin, a long-acting vasoconstrictor. The development of pancreatitis causes the release of other inflammatory mediators, which reduce blood flow in the microcirculation. The activation of intracellular trypsinogen initiates a cascade of mechanisms in pancreatitis. There is no specific treatment for acute pancreatitis. Protease inhibitors are not effective in treating severe acute pancreatitis. There is an important role of low-molecular-weight heparin in attenuating necrosis and restoring perfusion of the pancreas. Other drugs used are endothelin receptor antagonists, antagonist of interleukin-1 and interleukin-6 receptors, α-tocopherol, tumor necrosis factor-α and platelet-activating factor inhibitors, acetylsalicylic acid, and local intra-arterial injection of lidocaine. The prophylactic use of antibiotics is not recommended. The treatment outcome of acute pancreatitis is still unsatisfactory.

High lipasemia is frequent in Covid-19 associated acute respiratory distress syndrome

BACKGROUND

Covid-19 is a rapidly spreading viral disease that can cause severe acute respiratory distress syndrome (ARDS). Besides the lungs it can also affect other organs like the heart or the liver. Whether there is a pancreatic manifestation as well is currently unclear.

METHODS

and aims: We prospectively collected patient information of patients with Covid-19 associated ARDS in a registry (COvid Registry REChts der Isar intensive care Trial - CORRECT) and analyzed this patient cohort for signs of acute pancreatitis (e.g. lipase activity >3 times the upper limit).

RESULTS

12/38 (31.6%) patients with Covid-19 associated ARDS had a serum lipase activity >180 U/l. Median lipase activity was 422 U/l (186-1127). No patient showed typical findings of acute pancreatitis on imaging studies. On hemodynamic monitoring no patient had signs of intravascular fluid demand regarding MAP, GEDVI and therapy with vasopressors. To avoid worsening respiratory function no treatment with crystalloids was initiated. Lipasemia was not explained by gastroenteritis or renal insufficiency, occurred before as well as after viral clearance and 16.1 ± 6.0 days after the first symptoms. No patient developed severe acute pancreatitis during the follow up period of 35.8 ± 8.3 days.

CONCLUSION

High lipasemia without typical signs of acute pancreatitis is a frequent finding in severe Covid-19 associated ARDS. Considering the markedly high levels of serum lipase activity, we think impaired microcirculation in severely ill patients can explain this finding rather than extra-pancreatic co-morbidities (UTN: DRKS00021612).

Comparison of pancreatic microcirculation profiles in spontaneously hypertensive rats and Wistar-kyoto rats by laser doppler and wavelet transform analysis

Pancreatic microcirculatory dysfunction emerged as a novel mechanism in the development of hypertension. However, the changes of pancreatic microcirculation profiles in hypertension remain unknown. Pancreatic microcirculatory blood distribution pattern and microvascular vasomotion of spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats (WKYs) were determined by laser Doppler. Wavelet transform analysis was performed to convert micro-hemodynamic signals into time-frequency domains, based on which amplitude spectral scalograms were constructed. The amplitudes of characteristic oscillators were compared between SHRs and WKYs. The expression of eNOS was determined by immunohistochemistry, and plasma nitrite/nitrate levels were measured by Griess reaction. Additionally, endothelin-1, malondialdehyde, superoxide dismutase and interleukin-6 were determined by enzyme-linked immunosorbent assay. SHRs exhibited a lower scale blood distribution pattern with decreased average blood perfusion, frequency and amplitude. Wavelet transform spectral analysis revealed significantly reduced amplitudes of endothelial oscillators. Besides reduced expression of eNOS, the blood microcirculatory chemistry complements micro-hemodynamic profiles as demonstrated by an increase in plasma nitrite/nitrate, endothelin-1, malondialdehyde, interleukin-6 and a decrease of superoxide dismutase in SHRs. Here, we described abnormal pancreatic microcirculation profiles in SHRs, including disarranged blood distribution pattern, impaired microvascular vasomotion and reduced amplitudes of endothelial oscillators.

Serum soluble fibrinogen-like protein 2 concentration predicts delirium after acute pancreatitis

OBJECTIVE

Inflammation can cause delirium. Soluble fibrinogen-like protein 2 (sFGL2) is a modulator of the immune response and more recently found to be a biomarker for brain injury. This study was designed to discover the predictive capability of serum sFGL2 concentrations for delirium after acute pancreatitis (AP).

MATERIALS AND METHODS

In this prospective, observational study, serum sFGL2 concentrations were quantified in 184 healthy controls and in 184 AP patients. Disease severity was assessed by Acute Physiology and Chronic Health Care Evaluation II score, Ranson score, multiple organ dysfunction score, and sequential organ failure assessment score. Delirium was recorded during hospital stay. Predictors of delirium were identified using multivariate analysis.

RESULTS

Serum sFGL2 concentrations were substantially higher in AP patients than in controls. Serum sFGL2 concentrations were intimately correlated with the preceding severity parameters. Serum sFGL2 and the aforementioned severity parameters were independent predictors for delirium. Under receiver operating characteristic curve, the discriminatory ability of serum sFGL2 was equivalent to those of the above-mentioned severity parameters. Moreover, serum sFGL2 dramatically improved the predictive value of the aforementioned severity parameters.

CONCLUSIONS

Elevation of serum sFGL2 concentrations is strongly associated with the AP severity and has the potential to distinguish delirium after AP.

Fluid resuscitation via the rectum ameliorates hemodynamic disorders through adjusting aquaporin expression in an experimental severe acute pancreatitis model

Acute pancreatitis is an acute abdominal disease, with 10-20% of the cases deteriorating rapidly, accompanied by persistent organ failure and further development into severe acute pancreatitis (SAP). The aim of the present study was to investigate the mechanism of fluid resuscitation via the rectum in the early stages of SAP and the role of aquaporins (AQPs). An SAP model was constructed by injection of 5% sterile sodium taurocholate into the biliopancreatic duct of Sprague Dawley rats, and the mean arterial pressure (MAP) was continuously monitored via femoral artery catheterization. At 30 min after the construction of the SAP model, the rats in the fluid resuscitation groups were resuscitated with normal saline at a rate of 4 ml/kg/h through the venous or the rectal route. The AQP and Na⁺-K⁺-ATPase levels, and the correlation of the MAP and colon AQPs at the early stages of SAP were analyzed. The results demonstrated that the mRNA level of AQP-3 and AQP-4 in the distal colon decreased significantly in the group subjected to fluid resuscitation via the rectum, while no significant differences were identified in the Na⁺-K⁺-ATPase levels of the colon in that group. Furthermore, a negative correlation was identified between the expression of AQPs and the MAP (P<0.01). Thus, fluid resuscitation via the rectum appears to ameliorate hemodynamic disorders through adjusting the expression of AQP-3 and AQP-4 in the distal colon in an experimental SAP model.

Myxedema Coma Following the Administration of Gonadotropin-releasing Hormone Agonist Complicated by Acute Pancreatitis

Gonadotropin-releasing hormone (GnRH) agonists have been used for the treatment of various diseases. Although autoimmune thyroid disease has been reported as a rare complication of these agents, the symptoms are almost always transient and non-life-threatening. We herein report a rare case of an 83-year-old man receiving GnRH agonist treatment for prostate cancer who developed myxedema coma complicated by acute pancreatitis. This is the first report of myxedema coma potentially associated with a GnRH agonist. The follow-up of the thyroid function is necessary for patients undergoing treatment with GnRH agonists, especially those known to have or to be susceptible to autoimmune thyroid disease.

Exploring pancreatic pathology in Plasmodium falciparum malaria patients

Hypoglycaemia is an important complication of Plasmodium falciparum malaria infection, which can be lethal if not treated. A decrease in blood sugar (BS) level has been correlated with disease severity, parasitaemia and the use of certain antimalarial drugs. This study explored the relationship between pancreatic pathology, including the expressions of insulin and glucagon in the islets of Langerhans, and the BS levels in P. falciparum malaria patients. Pancreatic tissues from malaria patients were divided into three groups, namely those with BS < 40 mg/dl, BS = 40–120 mg/dl, and BS > 120 mg/dl. In P. falciparum malaria, pancreatic tissues showed numerous parasitised red blood cells (PRBCs) in the capillaries, oedema, acinar necrosis and the presence of inflammatory cells. The islet size and the expression of insulin were significantly increased in P. falciparum malaria patients with hypoglycaemia. In addition, insulin expression was positively correlated with islet size and negatively correlated with BS levels. This pioneer study documents an increase in insulin expression and an increase in islet size in hypoglycaemic patients with P. falciparum malaria. This could contribute to the pathogenesis of hypoglycaemia and provides evidence for the potential need to effectively manage the hypoglycaemia seen in malaria infection.

The protective effects of rutaecarpine on acute pancreatitis

Acute pancreatitis (AP) is the acute inflammation of the pancreas. The morbidity of AP has increased in recent years. Certain patients eventually develop severe AP (SAP), which rapidly progresses to multiple organ dysfunction; the incidence of this occurring in patients with AP is 20-30%. To date, no specific drugs or methods exist to treat this disease. Rutaecarpine relaxes vascular smooth muscle by stimulating calcitonin gene-related peptide (CGRP) release via activation of vanilloid receptor subtype 1 (VR1). It has been demonstrated that rutaecarpine induces a therapeutic effect on SAP. The present study was conducted to characterize the molecular mechanisms underlying the protective effects of rutaecarpine against AP using a rat model of AP. Gross pathological changes of the pancreas, as well as the pancreatic tissue histopathological score, were assessed following treatment with rutaecarpine, capsazepine or a combination of the two. Serum amylase activity was detected using an automatic biochemistry analyzer. Changes in the serum concentrations of interleukin (IL)-6, tumor necrosis factor (TNF-α), IL-10 and CGRP were assessed by ELISA and radioimmunoassay. The results demonstrated that pre-treatment with rutaecarpine markedly decreased pancreatic inflammation and necrosis, reduced the volume of ascites, and significantly increased the plasma concentration of CGRP and the serum concentration of IL-10, an anti-inflammatory cytokine. However, serum concentrations of the inflammatory cytokines IL-6 and TNF-α were decreased. The effect of rutaecarpine treatment markedly improved with increases in the drug dose. Capsazepine, as a competitive vanilloid receptor antagonist, abolished these protective effects of rutaecarpine against AP. Therefore, the results of the present study indicate that rutaecarpine protects against AP in rats by upregulating endogenous CGRP release via activation VR1 of, to improving the microcirculation of the pancreatic tissue and regulate the expression of inflammatory factors.

Chinese Herbal Medicines Attenuate Acute Pancreatitis: Pharmacological Activities and Mechanisms

Acute pancreatitis (AP) is a commonly occurring gastrointestinal disorder. An increase in the annual incidence of AP has been observed, and it causes acute hospitalization and high mortality. The diagnosis and treatment guidelines for AP recommend conservative medical treatments focused on reducing pancreatic secretion and secondary injury, as a primary therapeutic approach. Unfortunately, the existing treatment options have limited impact on the incidence and severity of AP due to the complex and multifaceted pathological process of this disease. In recent decades, Chinese herbal medicines (CHMs) have been used as efficient therapeutic agents to attenuate AP in Asian countries. Despite early cell culture, animal models, and clinical trials, CHMs are capable of interacting with numerous molecular targets participating in the pathogenesis of AP; however, comprehensive, up-to-date communication in this field is not yet available. This review focuses on the pharmacological activities of CHMs against AP in vitro and in vivo and the underlying mechanisms. A computational prediction of few selected and promising plant-derived molecules (emodin, baicalin, resveratrol, curcumin, ligustrazine, and honokiol) to target numerous proteins or networks involved in AP was initially established based on a network pharmacology simulation. Moreover, we also summarized some potential toxic natural products for pancreas in order to more safe and reasonable medication. These breakthrough findings may have important implications for innovative drug research and the future development of treatments for AP.

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.

Endothelial markers are associated with pancreatic necrosis and overall prognosis in acute pancreatitis: A preliminary cohort study

BACKGROUND

Endothelial injury is believed to play an important role in the evolution of pancreatic microcirculatory dysfunction and pancreatic necrosis (PN) in patients with acute pancreatitis (AP). The aim of this study was to investigate the role of three endothelial markers (von Willebrand factor, vWF; E-selectin; endothelial protein C receptor, EPCR) in the early phase of AP, especially the relationship between endothelial markers and PN.

METHODS

From March 2015 to March 2016, 57 AP patients admitted within 72 h of symptom onset in our hospital were included for this study. Blood samples were taken on admission and the clinical characteristics and outcomes of these patients were recorded. The levels of vWF, E-selectin and EPCR were measured using ELISA for analysis and compared with other severity markers of AP.

RESULTS

All the three markers were significantly different in healthy control, mild, moderate and severe AP patients. Moreover, the endothelial markers, especially vWF, also showed significant difference in patients with different extent of PN, as well as those with or without MODS. Additionally, the levels of endothelial markers correlated well with other commonly used markers of AP severity.

CONCLUSION

Elevated endothelium-related mediators (vWF, E-selectin and EPCR) appear to participate in the development of PN and may be a potential indicator of overall prognosis. Our results may help clinicians better understand the pathophysiological process of the development of PN.

Pancreatic injury in patients with septic shock: A literature review

Sepsis and septic shock are life threatening condition associated with high mortality rate in critically-ill patients. This high mortality is mainly related to the inadequacy between oxygen delivery and cellular demand leading to the onset of multiorgan dysfunction. Whether this multiorgan failure affect the pancreas is not fully investigated. In fact, pancreatic injury may occur because of ischemia, overwhelming inflammatory response, oxidative stress, cellular apoptosis and/or metabolic derangement. Increased serum amylase and/or lipase levels are common in patients with septic shock. However, imaging test rarely reveal significant pancreatic damage. Whether pancreatic dysfunction does affect the prognosis of patients with septic shock or not is still a matter of debate. In fact, only few studies with limited sample size assessed the clinical relevance of the pancreatic injury in this group of patients. In this review, we aimed to describe the epidemiology and the physiopathology of pancreatic injury in septic shock patients, to clarify whether it requires specific management and to assess its prognostic value. Our main finding is that pancreatic injury does not significantly affect the outcome in septic shock patients. Hence, increased serum pancreatic enzymes without clinical features of acute pancreatitis do not require further imaging investigations and specific therapeutic intervention.

Ameliorative Effects of Curcumin on Fibrinogen-Like Protein-2 Gene Expression, Some Oxido-Inflammatory and Apoptotic Markers in a Rat Model of l-Arginine-Induced Acute Pancreatitis

The aim of the study was to investigate the ameliorative effects of curcumin on fibrinogen like protein-2 (fgl-2), some oxido-inflammatory and apoptotic markers in rat-induced acute pancreatitis (AP). Seventy-five albino rats were divided into control group, l-arginine (l-Arg)-induced AP group, curcumin pre-treated group before AP induction, curcumin post-treated group after AP induction, and curcumin injected group only. AP group showed severe necrotizing pancreatitis confirmed by histopathological changes and elevations in serum amylase and lipase activities, levels of epithelial neutrophil-activating peptide 78, tissue content of protein carbonyls, levels of tumor necrosis factor α, and caspase-3 as well as myeloperoxidase activity. Significant elevation in pancreatic fgl-2 mRNA expression was detected in AP group. Improvement of all parameters was detected with increase of caspase-3 in both curcumin-treated groups that confirmed curcumin ameliorative effects against AP through induction of apoptosis and inhibition of micro-thrombosis, inflammation, and oxidative stress.

Ischemia-reperfusion rat model of acute pancreatitis: protein carbonyl as a putative early biomarker of pancreatic injury

Acute pancreatitis (AP) is an inflammatory disorder that can affect adjacent and/or remote organs. Some evidence indicates that the production of reactive oxygen species is able to induce AP. Protein carbonyl (PC) derivatives, which can also be generated through oxidative cleavage mechanisms, have been implicated in several diseases, but there is little or no information on this biomarker in AP. We investigated the association between some inflammatory mediators and PC, with the severity of ischemia-reperfusion AP. Wistar rats (n = 56) were randomly assigned in the following groups : control; sham, 15- or 180-min clamping of splenic artery, with 24 or 72 h of follow-up. The relationships between serum level of PC and thiobarbituric acid reactive species (TBARS) to myeloperoxidase (MPO) activity in tissue homogenates and to cytokines in culture supernatants of pancreatic samples were analyzed. MPO activity was related to the histology scores and increased in all clamping groups. Tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin-6 were higher in the 180-min groups. Significant correlations were found between MPO activity and the concentrations of TNF-α and IL-1β. PC levels increased in the 15-min to 24-h group. TBARS levels were not altered substantially. MPO activity and TNF-α and IL-1β concentrations in pancreatic tissue are correlated with AP severity. Serum levels of PC appear to begin to rise early in the course of the ischemia-reperfusion AP and are no longer detected at later stages in the absence of severe pancreatitis. These data suggest that PC can be an efficient tool for the diagnosis of early stages of AP.

Nimesulide may be more efficient than allopurinol in protecting pancreas from acute ischemia/reperfusion injury in an animal model

OBJECTIVE

To determine the influence of allopurinol and nimesulide in the protection of the pancreas from acute ischemia-reperfusion (I/R) injury.

MATERIALS AND METHODS

A total of 30 rabbits were divided into 3 groups, group A: acute I/R only; group B: allopurinol (30 mg/kg) was administered intravenously 10 minutes before ischemia; group C: nimesulide (50 mg/kg) was given intraperitoneally 20 minutes before ischemia. Neopterin and superoxide dismutase (SOD) levels were examined. Pancreatic biopsies were obtained for electron microscopy study.

RESULTS

The mean neopterin concentrations in group A are 3.56 ± 3.41, 7.74 ± 3.59, and 8.94 ± 2.86 ng/mL, respectively, in the stabilization, ischemia, and reperfusion phases; group B: 3.40 ± 3.03, 7.45 ± 8.89, and 10.64 ± 7.47 ng/mL; and group C: 3.41 ± 2.71, 5.67 ± 2.76, and 4.34 ± 2.87 ng/mL. The mean SOD concentrations in group A are 4.25 ± 1.79, 4.48 ± 1.60, and 5.57 ± 1.15 ng/mL; group B: 4.32 ± 0.81, 5.08 ± 1.10, and 4.45 ± 1.31 ng/mL; and group C: 4.10 ± 0.99, 5.23 ± 1.60, and 3.72 ± 1.30 ng/mL. Histopathology showed the least deterioration in group C.

CONCLUSION

Nimesulide is more efficient than allopurinol in protecting pancreas from acute I/R injury.

Effect of Resveratrol on NF-κB Activity in Rat Peritoneal Macrophages

This study was to investigate the inhibitive effect of resveratrol (RESV) on nuclear factor kappa B (NF-κB) expression and activity induced by lipopolysaccharide (LPS) in rat peritoneal macrophages (PMA). Male Sprague-Dawley (SD) rats were randomly divided into 7 groups, including control group, LPS group and RESV I-V group. In the LPS group, PMA were incubated in DMEM containing LPS (10 μg/ml), whereas in control group, PMA were incubated in DMEM only. In the RESV I-V groups, PMA were incubated in DMEM containing LPS (10 μg/ml) and different concentrations of RESV. After 24 hours of incubation, NF-κB activity in PMA, and the levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1) and nitric oxide (NO) in the culture medium were measured. In the concentrations of 1.25-5 μg/ml, RESV had a dose- dependent inhibitive effect on NF-κB activity in PMA as well as the expressions of TNF-α, IL-1 and NO in the culture medium contrasted with the LPS group. There was no significant difference in the levels of these pro-inflammatory factors between the groups of 5 μg/ml and 10 μg/ml RESV. In conclusion, RESV has the potential for the future application of preventing inflammatory diseases involving PMA.

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.

Decreased mortality in acute pancreatitis related to early aggressive hydration

OBJECTIVE

Early aggressive intravenous hydration is believed to prevent morbidity and mortality by preventing intravascular volume depletion and maintaining perfusion of the pancreas possibly preventing pancreatic necrosis. The following study was initiated to determine the relationship between the observed decrease in mortality and the role of early aggressive hydration.

METHODS

A consecutive series of patients with acute pancreatitis from a single community hospital in 1998 were compared to a consecutive series of patients with acute pancreatitis from the same institution in 2008.

RESULTS

Significantly more patients developed pancreatic necrosis; 26 (15%) of 173 patients in 1998 compared to 4 (4%) of 113 patients in 2008. The mean rate of hydration was significantly higher in 2008 compared with that in 1998 (P = 0.02). In 1998, hydration was provided at 184 mL/h during the first 6 hours and 188 mL/h during the first 12 hours compared with 284 mL/h during the first 6 hours and 221 mL/h during the first 12 hours in 2008. There was a significant decrease in mortality in 2008 compared with that in 1998 (3.5% vs 12%, P = 0.03).

CONCLUSIONS

The decrease in mortality seen in patients with acute pancreatitis during the last decade may be related to the increased aggressive hydration preventing pancreatic necrosis.

The beneficial effect of resveratrol on severe acute pancreatitis

Acute pancreatitis is a common kind of acute abdominal disease. The management of severe acute pancreatitis (SAP) is a challenge because of its high morbidity, which is due to systemic inflammatory response syndrome and multiorgan dysfunction syndrome. Therefore, it is important to explore therapies to control the disease's progression. A series of in vivo and in vitro experiments has demonstrated that resveratrol-an extract from Chinese herbs, grapes, and many plants-exhibits a wide range of biological and pharmacological activities, including anti-inflammatory, antioxidation, and chemopreventive effects, as well as the inhibition of platelet aggregation, which could benefit the treatment of SAP. Here, we examine the possible mechanism of resveratrol in treating the progression of SAP. Resveratrol could inhibit the production and progression of SAP through down-regulating pro-inflammatory cytokines, improving microcirculation, modulating cell apoptosis, and blocking calcium overload. We propose that resveratrol has a potentially therapeutic effect on the progression of SAP.

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.

Combined perioperative plasma endoglin and VEGF--a assessment in colorectal cancer patients

Colorectal cancer growth and spread is absolutely dependent on angiogenesis with vascular endothelial growth factor (VEGF) being the most important cytokine involved in the process. Endoglin, a membrane co-receptor for TGF-beta, has recently emerged as a sensitive index of cancer stage. There is now sufficient evidence indicating that microvessel density assessed by endoglin-immunostaining can correlate with stage of colorectal cancer and patient survival. An association of a soluble form of endoglin with lymph node and distant metastases has recently been reported in two studies. Both of them used local elaborated immunoassays for endoglin assessment. The aim of our study was to determine the efficacy of plasma endoglin, assessed using a commercial kit, as a marker of tumor spread and distant metastases in colorectal cancer patients. We studied 48 colorectal cancer patients, compared with 22 healthy subjects, using ELISA. We observed that colorectal cancer patients had increased plasma VEGF-A, but not endoglin levels. However, we found an association of plasma endoglin with the stage of malignancy. Endoglin levels were increased in metastasis-positive patients when compared to both metastasis-negative patients and healthy volunteers. Plasma endoglin correlated with VEGF-A, CEA and CA19.9. Endoglin assessment in plasma does not seem useful as a maker of colorectal cancer. Our observations indicate however that it might be helpful in selecting patients with metastatic disease.

Effect of baicalin on inflammatory mediator levels and microcirculation disturbance in rats with severe acute pancreatitis

OBJECTIVES

To investigate the effect of bacailin on inflammatory mediators and microcirculation disturbance in severe acute pancreatitis (SAP) rats and explore its therapeutic mechanism.

METHODS

The rats were randomly divided into SAP group, baicalin-treated group and sham operated group. At 3, 6, and 12 hours after operation, we examined the mortality rate of rats, ascites volume, and pancreatic pathological changes in each group and determined the contents of inflammatory mediators in blood as well as the changes in blood viscosity.

RESULTS

Compared with SAP group, treatment with baicalin is able to improve the pathological damage of the pancreas, reduce the contents of multiple inflammatory mediators in blood, decrease the amount of ascitic fluid, and reduce the mortality rates of SAP rats. The low-shear whole blood viscosity in baicalin-treated group (at 3 hours) as well as the high-shear and low-shear whole blood viscosity in baicalin-treated group (at 12 hours) were significantly lower than that in SAP group.

CONCLUSIONS

Baicalin has good prospects in the treatment for SAP because it can exert therapeutic effects on this disease through inhibiting the production of inflammatory mediators, decreasing blood viscosity, improving microcirculation, and mitigating the pathological damage of the pancreas.

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.

Inhibition of renin-angiotensin system in experimental acute pancreatitis in rats: a new therapeutic target?

OBJECTIVE

Pancreatic renin-angiotensin system has been implied to play a role in the regulation of pancreatic functions and could be a new therapeutic target in acute pancreatitis. The aim of this study was to evaluate the therapeutic potential of angiotensin-converting-enzyme inhibition by captopril and angiotensin II type 1 receptor inhibition by L-158809 and losartan experimentally in acute pancreatitis.

DESIGN

Rats were randomly divided into 15 groups. Acute edematous pancreatitis was induced by injection of cerulein 20microg/kg SC four times at hourly intervals. Severe necrotizing pancreatitis was induced by retrograde injection of 3% taurocholate into the biliary-pancreatic duct.

INTERVENTIONS

Captopril, L-158809 and losartan were given intraperitoneally. Main outcome features: pancreatic pathology, pancreatic myeloperoxidase activity and serum amylase activity were assessed.

RESULTS

Captopril decreased serum amylase (10,809+/-1867 vs. 4085+/-1028U/L, p<0.01), myeloperoxidase activity (3.5+/-0.5 vs. 1.5+/-0.1, p<0.05) and histopathological score (5.0+/-0.4 vs. 1.1+/-0.5, p<0.01) in acute edematous pancreatitis. In taurocholate induced severe necrotizing pancreatitis captopril ameliorated histopathological score (10.1+/-1.2 vs. 3.4+/-0.5, p<0.01), pancreatic parenchymal necrosis (4.5+/-0.6 vs. 0.0+/-0.0, p<0.001), fatty necrosis (2.8+/-0.9 vs. 0.1+/-0.1, p<0.01) and edema (2.1+/-0.3 vs. 1.4+/-0.3, p<0.05). However, L-158809 did not have similar beneficial effects on acute pancreatitis in rats while losartan decreased pancreatic parenchymal necrosis and neutrophil infiltration.

CONCLUSIONS

This study not only demonstrated the differential effects of captopril, losartan and L-158809 in acute pancreatitis but also showed that there is still much to investigate about pancreatic renin-angiotensin system. Inhibition of angiotensin-converting enzyme should be evaluated carefully as a potential new therapeutic target in acute pancreatitis.

Acute edematous and necrotic pancreatitis in a porcine model

OBJECTIVE

It is unclear why pancreatitis progresses either to mild edematous disease or to severe necrotic disease. The aim of the study was to shed some light on this topic by investigating differences during the early stages of necrotic and edematous pancreatitis.

MATERIAL AND METHODS

Piglets were randomized into two groups. Necrotic pancreatitis was induced with retrograde injection of 20% taurocholic acid (1 ml/kg), and edematous pancreatitis was induced with 0.9% NaCl (1 ml/kg). Central hemodynamics was measured, and pancreatic microcirculation was directly examined by intravital microscopy. Vascular permeability to proteins and albumin was measured by microdialysis. Apoptosis and claudins 2, 3, 4, 5, and 7 were analyzed from pancreatic tissue samples. Blood samples were taken for analysis of blood cell counts, blood gases, lipase, and amylase.

RESULTS

Hemodynamic changes were similar in both groups, whereas microcirculatory impairment was more pronounced in necrotic pancreatitis. Necrosis was associated only with necrotic pancreatitis. Apoptosis increased only in edematous pancreatitis. The number of blood neutrophils and monocytes increased and lymphocyte and platelet counts decreased in both groups. Necrotic pancreatitis was associated with increased permeability to albumin and proteins. Expression of claudins 3, 4, 5, and 7 was not changed during pacreatitis, but in acinar cells, membranous expression of claudin-2 increased in both groups.

CONCLUSIONS

The results show that acute edematous pancreatitis is characterized by induction of apoptosis, whereas full-blown pancreatitis is characterized by necrosis. Impaired vascular permeability to albumin and protein is related to the early phase of necrotic pancreatitis. Claudin-2 increases during acute necrotic and edematous pancreatitis and may be related to impaired permeability.

Pathophysiological role of platelets and platelet system in acute pancreatitis

The most successful approach for restoring normal long-term glucose homeostasis in type I diabetes mellitus is whole-organ pancreas transplantation. Graft pancreatitis is observed in up to 20% of patients and may lead to loss of the transplanted organ. Several pathophysiological events have been implicated in this form of pancreatitis. The most important cause of early graft pancreatitis is ischemia/reperfusion (I/R)-related disturbance of microvascular perfusion with subsequent hypoxic tissue damage. Recently, considerable evidence accumulated that, among a variety of other pathophysiological events, the activation of platelets can contribute to I/R injury in the course of acute pancreatitis experimentally and clinically. This review summarizes the events affecting platelet function and, therefore, pancreatic microcirculation leading to acute pancreatitis. Therapeutic approaches and own results are presented.

Galanin in the regulation of pancreatic vascular perfusion

OBJECTIVES

Acute pancreatitis is associated with compromised pancreatic microcirculation. Galanin is a vasoactive neuropeptide, but its role in the regulation of pancreatic vascular perfusion (PVP) is unclear.

METHODS

Localization of galanin immunoreactivity was investigated by immunohistochemistry, and the effects of bolus doses of galanin or the antagonist galantide on blood pressure (BP) and PVP (by laser Doppler fluxmetry) were determined in anesthetized possums.

RESULTS

Galanin immunoreactivity was abundant in the possum pancreas particularly around blood vessels. Galanin (0.001-10 nmol) produced a dose-dependent increase in BP (to 177% of baseline) and a complex PVP response consisting of a transient increase, then a fall below baseline with recovery to above baseline. Galantide (0.003-30 nmol) caused a dose-dependent biphasic response in BP, with a reduction, recovery, then a further fall, followed by recovery, whereas PVP increased (178%) then fell (to 56%) of baseline. Similar effects were produced by continuous intravenous infusion of galanin (1 and 10 nmol) or galantide (3 and 30 nmol). The second-phase response of these agents is probably a passive response of the pancreatic vasculature to systemic cardiovascular effects.

CONCLUSIONS

These data suggest that galanin acutely reduces PVP, whereas galantide increases it, implying galanin may be important in the regulation of PVP.

The role of Doppler sonography in predicting severity of acute pancreatitis

PURPOSE

To investigate the role of Doppler sonography (DUS) examination of major abdominal arteries in predicting severity of acute pancreatitis (AP).

METHODS

Twenty-nine patients diagnosed with AP and 14 controls were blindly and prospectively evaluated with Doppler sonography. Disease severity was defined clinically according to acute physiology and chronic health evaluation (APACHE II) score and was classified as severe for APACHE II score > or =8. DUS examination included the measurement of peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI), and resistance index (RI) of the celiac artery (CA) and superior mesenteric artery (SMA). Statistical analysis included Mann-Whitney U test, Student t test, and receiver operating characteristic curve analysis.

RESULTS

Twelve patients had severe AP and 17 had mild AP. PSV, EDV, and PI of the CA and RI of the SMA were higher in the severe AP group than in the mild AP and control groups (p < 0.001 and p < 0.0001, respectively). The sensitivity and specificity were 100% and 94%, respectively, for a 87 cm/second CA PSV cutoff value, 75% and 100%, respectively, for a 22 cm/second CA EDV cutoff value, 92% and 82%, respectively, for a 1.29 CA PI cutoff value, and 100% and 100%, respectively, for a 0.86 SMA RI cutoff value.

CONCLUSION

DUS can be useful in predicting the severity of AP in the early period of admission phase of the disease.

Influence of atropine therapy on fenthion-induced pancreatitis

OBJECTIVE

We searched the influence of dose and timing of atropine therapy in fenthion-induced pancreatitis model.

METHODS

All rats were intoxicated with fenthion except the control group. Two milligrams of atropine was administered for 24 hours in a high dose atropine group while a low dose atropine group received 100 micrograms of atropine for 24 hours. One group received 2 milligrams of atropine in the first four hours of intoxication while the other group received 2 milligrams of atropine in the last four hours before sacrifice. All rats were sacrificed 24 hours after intoxication. Pseudo-cholinesterase and lipase concentrations and histopathological markers of pancreatitis were studied.

RESULTS

None of the models in this study completely prevented pancreatitis, however high dose atropine that is administered for 24 hours or the first four hours after intoxication prevented severe pancreatitis.

CONCLUSION

Atropine administration influence on fenthion-induced pancreatitis should be studied for other organophosphates in animals and humans.

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.

Ligustrazine alleviates acute renal injury in a rat model of acute necrotizing pancreatitis

AIM: To evaluate the effect of ligustrazine, a traditional Chinese medicine, on renal injury in a rat model of acute necrotizing pancreatitis (ANP).

METHODS: A total of 192 rats were randomly divided into three groups: control (C group), ANP without treatment (P group), and ANP treated with ligustrazine (T group). Each group was further divided into 0.5, 2, 6, 12 h subgroups. All rats were anesthetized with an intraperitoneal injection of sodium pentobarbital. Sodium taurocholate was infused through the pancreatic membrane to induce ANP. T group was infused sodium taurocholate as above, and 0.6% ligustrazine was then administered via the femoral vein. Serum urea nitrogen (BUN) and creatinine (Cr) concentrations were measured for the evaluation of renal function. The effects of ligustrazine on the severity of renal injury were assessed by renal function, TXA₂/PGI₂ and histopathological changes. Renal blood flow was determined by the radioactive microsphere technique (RMT).

RESULTS: Compared with control group, the renal blood flow in P group was decreased significantly. Serious renal and pancreatic damages were found in P group, the BUN and Cr levels were elevated significantly, and the ratio of TXA₂ to PGI₂ was increased at 2, 6 and 12 h. Compared with P group, the blood flow of kidney was elevated significantly at 6 and 12 h after induction of ANP, the renal and pancreatic damages were attenuated, and the BUN and Cr levels were decreased significantly, and the ratio of TXA₂ to PGI₂ was decreased at 6 and 12 h in T group.

CONCLUSION: Microcirculatory disorder (MCD) is an important factor for renal injury in ANP. Ligustrazine can ameliorate the condition of MCD and the damage of pancreas and kidney.

Preventive effect of tetramethylpyrazine on intestinal mucosal injury in rats with acute necrotizing pancreatitis

AIM: To evaluate the role of microcirculatory disorder (MCD) and the therapeutic effectiveness of tetramethylpyrazine (TMP) on intestinal mucosa injury in rats with acute necrotizing pancreatitis (ANP).

METHODS: A total of 192 Sprague-Dawley rats were randomly divided into three groups: normal control group (C group), ANP group not treated with TMP (P group), ANP group treated with TMP (T group). An ANP model was induced by injection of 50 g/L sodium taurocholate under the pancreatic membrane (4 mL/kg). C group received isovolumetric injection of 9 g/L physiological saline solution using the same method. T group received injection of TMP (10 mL/kg) via portal vein. Radioactive biomicrosphere technique was used to measure the blood flow at 0.5, 2, 6 and 12 h after the induction of ANP. Samples of pancreas, distal ileum were collected to observe pathological changes using a validated histology score. Intestinal tissues were also used for examination of myeloperoxidase (MPO) expressed intracellularly in azurophilic granules of neutrophils.

RESULTS: The blood flow was significantly lower in P group than in C group (P < 0.01). The pathological changes were aggravated significantly in P group. The longer the time, the severer the pathological changes. The intestinal MPO activities were significantly higher in P group than in C group (P < 0.01). The blood flow of intestine was significantly higher in T group than in P group after 2 h (P < 0.01). The pathological changes were alleviated significantly in T group. MPO activities were significantly lower in T group than in P group (P < 0.01 or P < 0.05). There was a negative correlation between intestinal blood flow and MPO activity (r = -0.981, P < 0.01) as well as between intestinal blood flow and pathologic scores (r = -0.922, P < 0.05).

CONCLUSION: MCD is an important factor for intestinal injury in ANP. TMP can ameliorate the condition of MCD and the damage to pancreas and intestine.

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.

Captopril, an Angiotensin-converting enzyme inhibitor, attenuates the severity of acute pancreatitis in rats by reducing expression of matrix metalloproteinase 9

It has been reported that matrix metalloproteinase 9 (MMP-9) disrupts basement membrane and increases vascular permeability. MMP-9 therefore might participate in the pathogenesis of severe acute pancreatitis (SAP). Captopril, an angiotensin-converting enzyme inhibitor, could reduce MMP-9 expression. However, the effect of captopril on the outcome of SAP is not ascertained. The aim of this study was to determine whether captopril attenuates the severity of SAP by reducing MMP-9 expression. Thirty Sprague-Dawley rats were randomly divided into 3 groups (n = 10 for each). Rats were given intraperitoneal injection of saline (SAP group) or captopril (4 mg/kg) (treated group), and then given retrograde infusion of 5% sodium taurocholate (1.5 ml/kg) into the pancreatic duct under laparotomy to induce SAP. One group of rats, injected with saline, underwent only sham operation (Control). Experimental samples were collected at 24 hrs after the induction of SAP or sham operation. Various markers of severity of SAP, such as serum levels of amylase and trypsinogen activation peptide and the vascular permeability, were increased in rats with SAP, but were significantly decreased in captopril-treated rats (p < 0.01). Likewise, the serum MMP-9 levels and expression levels of pancreatic tissue MMP-9 were significantly higher in rats with SAP than those in captopril-treated rats and control rats (p < 0.01 for both parameters), but showed no difference between captopril-treated and control rats. These results suggest that captopril may attenuate vascular permeability by reducing MMP-9 expression in SAP, thereby ameliorating severity of the disease. The use of captopril might become a new therapeutic agent for SAP.

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.

Endogenous hypertriglyceridemia intensifies the course of cerulein-induced pancreatitis in rat: relation with changes in the VLDL composition

AIMS

To study if the course of cerulein-induced pancreatitis in rats changes in a state of triglyceride-rich lipoprotein metabolism alteration.

METHODS

Two groups of rats received control diet during a 90-day period (A) and sucrose-rich diet to induce endogenous hypertriglyceridemia (B). Subgroups A2 and B2 received i.p. 45 microg cerulein/kg body weight (to induce acute pancreatitis). Histological examination of pancreas tissue, serum pancreatic lipase, lipoprotein profile and VLDL chemical composition were assessed. Then, pancreatic lipase hydrolytic activity on VLDL-triglycerides was evaluated in vitro.

RESULTS

Cellular vacuolization was observed in all of the cerulein-injected rats, but only in subgroup B2 fat necrosis was present. Serum triglycerides were higher in subgroup B1 than in subgroup A1 (mean +/- SEM, mg/dl 123,77 +/- 25.7 vs. 65.8 +/- 7, p < 0.01). Triglycerides from rats fed with sucrose-rich diet, decreased after cerulein-induced pancreatitis (80.38 +/- 11.3 vs. 123,77 +/- 25.7, p < 0.02). Moreover, the endogenous hypertriglyceridemic rats showed an increment of VLDL triglyceride content, which decreased when rats were injected with cerulein. A negative correlation was found between VLDL-triglyceride content and serum pancreatic lipase activity (r = 0.58, p < 0.02). The in vitro assay showed a decrease in VLDL-triglyceride content post incubation with pancreatic lipase enriched serum (mean +/- SD: 59.2 +/- 27.7%, p < 0.01).

CONCLUSIONS

The endogenous hypertriglyceridemia intensifies the course of cerulein-induced pancreatitis and it could be related to the decrease in VLDL-triglycerides as a consequence of pancreatic lipase hydrolytic activity.

Toll-like receptor 4 detected in exocrine pancreas and the change of expression in cerulein-induced pancreatitis

OBJECTIVES

To detect Toll-like receptor 4 (TLR4) expression and distribution in rat pancreas and the change of TLR4 expression in cerulein-induced pancreatitis (CIP).

METHODS

Acute pancreatitis was induced by subcutaneous injections of cerulein at a total dose of 20 microg/kg. Immunohistochemistry (IHC) was used to detect and localize TLR4 in rat pancreas, and real-time reverse transcription-polymerase chain reaction (RT-PCR) was used to quantitatively determine the expression of TLR4 mRNA in CIP.

RESULTS

IHC showed the presence of TLR4 in rat pancreas, and its distribution was specifically localized to pancreatic ductal epithelium, vascular endothelium, and islet. No TLR4 staining was detected in exocrine acinar cells. Real-time RT-PCR results revealed low-level TLR4 mRNA expression in the rat pancreas, and the change of TLR4 in CIP only developed within the first 4 hours, which is a rapid up-regulation process that peaks at the first hour. TLR4 mRNA was sustained at baseline level from 4 to 24 hours.

CONCLUSIONS

TLR4 protein was expressed in pancreas and localized to epithelial (pancreatic duct) or endothelial (vessels) tissues; TLR4 responded favorably to the inflammatory process, and the change of expression was characterized as a rapid up-regulation in the early stage of CIP.

Pituitary adenylate cyclase activating-peptide and its receptor antagonists in development of acute pancreatitis in rats

AIM: Pituitary adenylate cyclase activating-peptide (PACAP) is a late member of the secretin/glucagon/vasoactive intestinal peptide (VIP) family of brain-gut peptides. It is unknown whether PACAP takes part in the development of acute pancreatitis and whether PACAP or its antagonists can be used to suppress the progression of acute pancreatitis. We investigated the actions of PACAP and its receptor antagonists in acute pancreatitis on rats.

METHODS: Acute pancreatitis was induced in rats with caerulein or 3.5% sodium taurocholate. The rats were continuously infused with 5-30 μg/kg PACAP via jugular vein within the first 90 min, while 10-100 μg/kg PACAP6-27 and (4-Cl-D-Phe⁶, Leu¹⁷) VIP (PACAP receptor antagonists) were intravenously infused for 1 h. Biochemical and histopathological assessments were made at 4 h after infusion. Pancreatic and duodenal PACAP concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Chinese ink-perfused pancreas was fixed, sectioned and cleared for counting the functional capillary density.

RESULTS: PACAP augmented caerulein-induced pancreatitis and failed to ameliorate sodium taurocholate-induced pancreatitis. ELISA revealed that relative concentrations of PACAP in pancreas and duodenum were significantly increased in both sodium taurocholate- and caerulein-induced pancreatitis compared with those in normal controls. Unexpectedly, PACAP6-27 and (4-Cl-D-Phe⁶, Leu¹⁷) VIP could induce mild acute pancreatitis and aggravate caerulein-induced pancreatitis with characteristic manifestations of acute hemorrhagic/necrotizing pancreatitis. Functional capillary density of pancreas was interpreted in the context of pancreatic edema, and calibrated functional capillary density (calibrated FCD), which combined measurement of functional capillary density with dry weight/wet weight ratio, was introduced. Hyperemia or congestion, rather than ischemia, characterized pancreatic microcirculatory changes in acute pancreatitis.

CONCLUSION: PACAP may take part in the pathogenesis of acute pancreatitis in rats. The two PACAP receptor antagonsits might act as partial agonists. Calibrated functional capillary density can reflect pancreatic microcirculatory changes in acute pancreatitis.

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