Clinical observation of immunity in patients with secondary infection from severe acute pancreatitis. Inflamm Res. 2012;61:743-748. [PMID: 22466614 DOI: 10.1007/s00011-012-0467-1]

Therapeutic efficacy of Xuebijing injection in treating severe acute pancreatitis and its mechanisms of action: A comprehensive survey

BACKGROUND

Severe acute pancreatitis (SAP) is a life-threatening condition associated with high mortality and limited therapeutic options. Current management strategies focus on infection prevention, immune regulation, and anticoagulation. Xuebijing Injection (XBJ), a widely used traditional Chinese medicine-derived intravenous preparation, has shown promising therapeutic effects in SAP. Herein, we sought to evaluate clinical and preclinical evidence on XBJ to reveal its potential mechanisms of action, and provide insights to guide future research and clinical applications.

METHODS

We conducted a comprehensive survey of studies on XBJ in the treatment of SAP across PubMed, Embase, Cochrane Library, CBM, CNKI, Wanfang and VIP databases from their inception to March 21st, 2024.

RESULTS

A total of 239 studies were included, comprising 12 animal experiments, 7 systematic reviews, 220 clinical trials. Mechanistic studies suggest that XBJ downregulates the expression of inflammatory mediators, improves immune function, and alleviates oxidative stress via multiple signaling pathways, including the TLR4/NF-κB, p38-MAPK, HMGB1/TLR, TLR4/NF-κB, FPR1/NLRP3, and JAK/STAT pathways. These effects contribute to reducing organ damage. Compared to standard treatment, XBJ has more effective at reducing mortality and complications, improving overall clinical outcomes, shortening ventilator use time, and hospital stay in SAP patients.

CONCLUSIONS

Preclinical evidence and clinical trial data indicated that XBJ can simultaneously regulate inflammatory responses, immune function, microcirculatory disorders, oxidative stress, and apoptosis. However, further research is required to elucidate the specific mechanisms of action, clinical characteristics and safety of XBJ.

From pancreas to lungs: The role of immune cells in severe acute pancreatitis and acute lung injury

BACKGROUND

Severe acute pancreatitis (SAP) is a potentially lethal inflammatory pancreatitis condition that is usually linked to multiple organ failure. When it comes to SAP, the lung is the main organ that is frequently involved. Many SAP patients experience respiratory failure following an acute lung injury (ALI). Clinicians provide insufficient care for compounded ALI since the underlying pathophysiology is unknown. The mortality rate of SAP patients is severely impacted by it.

OBJECTIVE

The study aims to provide insight into immune cells, specifically their roles and modifications during SAP and ALI, through a comprehensive literature review. The emphasis is on immune cells as a therapeutic approach for treating SAP and ALI.

FINDINGS

Immune cells play an important role in the complicated pathophysiology ofSAP and ALI by maintaining the right balance of pro- and anti-inflammatory responses. Immunomodulatory drugs now in the market have low thepeutic efficacy because they selectively target one immune cell while ignoring immune cell interactions. Accurate management of dysregulated immune responses is necessary. A critical initial step is precisely characterizing the activity of the immune cells during SAP and ALI.

CONCLUSION

Given the increasing incidence of SAP, immunotherapy is emerging as a potential treatment option for these patients. Interactions among immune cells improve our understanding of the intricacy of concurrent ALI in SAP patients. Acquiring expertise in these domains will stimulate the development of innovative immunomodulation therapies that will improve the outlook for patients with SAP and ALI.

Mesenteric adipose tissue B lymphocytes promote intestinal injury in severe acute pancreatitis by mediating enteric pyroptosis

BACKGROUND

Visceral adipose tissue (VAT) has been linked to the severe acute pancreatitis (SAP) prognosis, although the underlying mechanism remains unclear. It has been reported that pyroptosis worsens SAP. The present study aimed to verify whether mesenteric adipose tissue (MAT, a component of VAT) can cause secondary intestinal injury through the pyroptotic pathway.

METHODS

Thirty-six male Sprague Dawley (SD) rats were divided into six different groups. Twelve rats were randomly divided into the SAP and control groups. We monitored the changes of MAT and B lymphocytes infiltration in MAT of SAP rats. Twelve SAP rats were injected with MAT B lymphocytes or phosphate buffer solution (PBS). The remaining twelve SAP rats were first injected with MAT B lymphocytes, and then with MCC950 (NLRP3 inhibitor) or PBS. We collected blood and tissue samples from pancreas, gut and MAT for analysis.

RESULTS

Compared to the control rats, the SAP group showed inflammation in MAT, including higher expression of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), lower expression of IL-10, and histological changes. Flow cytometry analysis revealed B lymphocytes infiltration in MAT but not T lymphocytes and macrophages. The SAP rats also exhibited intestinal injury, characterized by lower expression of zonula occludens-1 (ZO-1) and occludin, higher levels of lipopolysaccharide and diamine oxidase, and pathological changes. The expression of NLRP3 and n-GSDMD, which are responsible for pyroptosis, was increased in the intestine of SAP rats. The injection of MAT B lymphocytes into SAP rats exacerbated the inflammation in MAT. The upregulation of pyroptosis reduced tight junction in the intestine, which contributed to the SAP progression, including higher inflammatory indicators and worse histological changes. The administration of MCC950 to SAP + MAT B rats downregulated pyroptosis, which subsequently improved the intestinal barrier and ameliorated inflammatory response of SAP.

CONCLUSIONS

In SAP, MAT B lymphocytes aggravated local inflammation, and promoted the injury to the intestine through the enteric pyroptotic pathway.

Intestinal Mucosal Immune Barrier: A Powerful Firewall Against Severe Acute Pancreatitis-Associated Acute Lung Injury via the Gut-Lung Axis

The pathogenesis of severe acute pancreatitis-associated acute lung injury (SAP-ALI), which is the leading cause of mortality among hospitalized patients in the intensive care unit, remains incompletely elucidated. The intestinal mucosal immune barrier is a crucial component of the intestinal epithelial barrier, and its aberrant activation contributes to the induction of sustained pro-inflammatory immune responses, paradoxical intercellular communication, and bacterial translocation. In this review, we firstly provide a comprehensive overview of the composition of the intestinal mucosal immune barrier and its pivotal roles in the pathogenesis of SAP-ALI. Secondly, the mechanisms of its crosstalk with gut microbiota, which is called gut-lung axis, and its effect on SAP-ALI were summarized. Finally, a number of drugs that could enhance the intestinal mucosal immune barrier and exhibit potential anti-SAP-ALI activities were presented, including probiotics, glutamine, enteral nutrition, and traditional Chinese medicine (TCM). The aim is to offer a theoretical framework based on the perspective of the intestinal mucosal immune barrier to protect against SAP-ALI.

The impact of multi-drug resistant Pseudomonas aeruginosa infections on acute pancreatitis patients

INTRODUCTION

Acute pancreatitis (AP) accounts for a high proportion of digestive diseases worldwide and has a high risk of infection. Pseudomonas aeruginosa, a common pathogen of hospital infections, has been observed to increase the resistance rate to several antibiotics, causing difficulties in treatments. Our study aims to investigate the impact of the multi-drug resistant Pseudomonas aeruginosa (MDR-PA) infections on AP patients.

METHODS

At two Chinese tertiary referral centers for AP patients infected with MDR-PA, a retrospective case-control study with a 1:2 case-control ratio was performed. Comparisons were preformed between with/without MDR-PA infections and different drug-resistance of MDR-PA infections patients, respectively. Independent risk factors of overall mortality were assessed via univariate and multivariate binary logistic regression analyses, and the distribution and antibiotic resistant rates of strains were described.

RESULTS

Mortality in AP patients with MDR-PA infections was significantly higher than in those without MDR-PA infections (7 (30.4%) vs. 4 (8.7%), P = 0.048). The rate of prophylactic use of carbapenem for 3 days (0 vs. 50%, P = 0.019) and the incidence rate of multiple organ failure (MOF) (0 vs. 57.1%, P = 0.018) were remarkably higher in the carbapenem-resistant Pseudomonas aeruginosa group compared with the carbapenem-sensitive Pseudomonas aeruginosa group. In the multivariate analysis, the severe categories of AP (OR = 13.624, 95% CIs = 1.567-118.491, P = 0.018) and MDR-PA infections (OR = 4.788, 95% CIs = 1.107-20.709, P = 0.036) were independent risk factors for mortality. The resistance rates of MDR-PA strains were low for amikacin (7.4%), tobramycin (3.7%), and gentamicin (18.5%). The resistance rates of MDR-PA strains to imipenem and meropenem were up to, 51.9% and 55.6%, respectively.

CONCLUSION

In AP patients, severe categories of AP and MDR-PA infections were both independent risk factors for mortality. Inappropriate use of carbapenem antibiotics and MOF were related to carbapenem-resistant Pseudomonas aeruginosa infections. Amikacin, tobramycin, and gentamicin are recommended for the treatment of AP patients with MDR-PA infections.

Innate Lymphoid Cells: Emerging Players in Pancreatic Disease

Common pancreatic diseases have caused significant economic and social burdens worldwide. The interstitial microenvironment is involved in and plays a crucial part in the occurrence and progression of pancreatic diseases. Innate lymphoid cells (ILCs), an innate population of immune cells which have only gradually entered our visual field in the last 10 years, play an important role in maintaining tissue homeostasis, regulating metabolism, and participating in regeneration and repair. Recent evidence indicates that ILCs in the pancreas, as well as in other tissues, are also key players in pancreatic disease and health. Herein, we examined the possible functions of different ILC subsets in common pancreatic diseases, including diabetes mellitus, pancreatitis and pancreatic cancer, and discussed the potential practical implications of the relevant findings for future further treatment of these pancreatic diseases.

Role of Interleukin-17 in Acute Pancreatitis

Acute pancreatitis (AP) is a leading cause of death and is commonly accompanied by systemic manifestations that are generally associated with a poor prognosis. Many cytokines contribute to pancreatic tissue damage and cause systemic injury. Interleukin-17 (IL-17) is a cytokine that may play a vital role in AP. Specifically, IL-17 has important effects on the immune response and causes interactions between different inflammatory mediators in the AP-related microenvironment. In this literature review, we will discuss the existing academic understanding of IL-17 and the impacts of IL-17 in different cells (especially in acinar cells and immune system cells) in AP pathogenesis. The clinical significance and potential mechanisms of IL-17 on AP deterioration are emphasized. The evidence suggests that inhibiting the IL-17 cytokine family could alleviate the pathogenic process of AP, and we highlight therapeutic strategies that directly or indirectly target IL-17 cytokines in acute pancreatitis.

Prognostic value of peripheral blood CD14+HLA-DR+ monocytes in patients with acute pancreatitis

Acute pancreatitis (AP) is characterized by a potent pro-inflammatory response and concomitant anti-inflammatory response leading to a state of immunosuppression. Decreased HLA (Human Leukocyte Antigen)-DR expression on monocytes is a reliable cellular marker of immune suppression. The main objective of this study was to investigate the clinical value of the percentage of peripheral blood CD14+ HLA-DR+ monocytes (mHLA-DR) for diagnosis and assessment of severity, development of organ failures (OF), local complications (LC), and infected necrosis (IN), and outcome in patients with AP. Flow cytometry was used to measure the percentage of peripheral blood mHLA-DR at different time points in 82 patients with AP enrolled during the period of 2012-2018 admitted to University Hospital Stara Zagora, Bulgaria. The percentages of peripheral blood mHLA-DR in AP patients were significantly associated with severity, development of LC, OF, IN (measured at admission, on the 48^th hour and on the 5^th day) and with outcome (measured on the 5^th day) of AP. The value of peripheral blood mHLA-DR may be used as a biological marker in the diagnosis and assessment of severity, development of OF, LC, IN and to predict outcome in AP.

Circulating Lymphocyte Subsets Induce Secondary Infection in Acute Pancreatitis

Acute pancreatitis (AP) is considered a cascade of immune responses triggered by acinar cell necrosis. AP involves two main processes of systemic inflammatory response syndrome and subsequent compensatory anti-inflammatory response syndrome. Although great efforts have been made regarding AP therapy, the mortality rate of AP remains high. Secondary infection acts a lethal factor in AP. Lymphocytes act as major immune mediators in immune responses in the course of this disease. However, the relationship between lymphocytes and secondary infection in AP is unclear. This review summarizes the variation of lymphocytes and infection in AP. Knowledge of the characterization of circulating lymphocyte abnormalities is relevant for understanding the pathophysiology of AP.

T Lymphocytes: A Promising Immunotherapeutic Target for Pancreatitis and Pancreatic Cancer?

Pancreatic disorders cause a broad spectrum of clinical diseases, mainly including acute and chronic pancreatitis and pancreatic cancer, and are associated with high global rates of morbidity and mortality. Unfortunately, the pathogenesis of pancreatic disease remains obscure, and there is a lack of specific treatments. T lymphocytes (T cells) play a vital role in the adaptive immune systems of multicellular organisms. During pancreatic disease development, local imbalances in T-cell subsets in inflammatory and tumor environments and the circulation have been observed. Furthermore, agents targeting T cells have been shown to reverse the natural course of pancreatic diseases. In this review, we have discussed the clinical relevance of T-cell alterations as a potential outcome predictor and the underlying mechanisms, as well as the present status of immunotherapy targeting T cells in pancreatitis and neoplasms. The breakthrough findings summarized in this review have important implications for innovative drug development and the prospective use of immunotherapy for pancreatitis and pancreatic cancer.

Bacterial translocation in acute pancreatitis

Bacterial translocation is a phenomenon in which live bacteria or their products cross the intestinal barrier to other organs or the circulatory system. Gut translocation of bacteria has been reported in both animal models, and clinical trials often accompany acute pancreatitis and are believed to be linked to patient outcome, especially in severe acute pancreatitis. Therefore, the mechanisms of intestinal bacterial translocation in acute pancreatitis have become a topic of interest in recent years. This review discusses Bacterial translocation in acute pancreatitis, identifies possible mechanisms of action, and provides an overview of the methods used to detect Bacterial translocation in acute pancreatitis. This review also highlights areas that require further research.

Effect of regional arterial infusion combined with early enteral nutrition on severe acute pancreatitis

Objective

To measure the therapeutic effects of regional arterial infusion (RAI) in combination with early enteral nutrition (EEN) in patients with severe acute pancreatitis (SAP).

Methods

A prospective randomized controlled study enrolled patients with SAP. They were randomly divided into a conventional treatment group that served as the control and a combination therapy group that received RAI combined with EEN. The Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) scores, the levels of serum biochemical indices, functional recovery, the incidence of complications and total effectiveness rate were evaluated.

Results

A total of 100 patients were enrolled in the study. The APACHE II scores and the concentrations of blood glucose, serum amylase, white blood cell count, C-reactive protein, tumour necrosis factor-α, interleukin (IL)-6, IL-10 and IL-17 were significantly decreased, while albumin and serum calcium and total effectiveness rate in the combination therapy group were significantly higher than in the conventional treatment group. The combination therapy group had a significantly reduced time to abdominal pain relief, time of first defaecation, hospital stay and incidence of complications compared with the conventional treatment group.

Conclusion

The combination of RAI and EEN improved clinical biochemical indices, reduced the incidence of complications and promoted early recovery in patients with SAP.

Timing, distribution, and microbiology of infectious complications after necrotizing pancreatitis

BACKGROUND

Acute pancreatitis (AP) is a common acute abdominal disease worldwide, and its incidence rate has increased annually. Approximately 20% of AP patients develop into necrotizing pancreatitis (NP), and 40% to 70% of NP patients have infectious complications, which usually indicate a worse prognosis. Infection is an important sign of complications in NP patients.

AIM

To investigate the difference in infection time, infection site, and infectious strain in NP patients with infectious complications.

METHODS

The clinical data of AP patients visiting the Department of General Surgery of Xuanwu Hospital of Capital Medical University from January 1, 2014 to December 31, 2018 were collected retrospectively. Enhanced computerized tomography or magnetic resonance imaging findings in patients with NP were included in the study. Statistical analysis of infectious bacteria, infection site, and infection time in NP patients with infectious complications was performed, because knowledge about pathogens and their antibiotic susceptibility patterns is essential for selecting an appropriate antibiotic. In addition, the factors that might influence the prognosis of patients were analyzed.

RESULTS

In this study, 539 strains of pathogenic bacteria were isolated from 162 patients with NP infection, including 212 strains from pancreatic infections and 327 strains from extrapancreatic infections. Gram-negative bacteria were the main infectious species, the most common of which were Escherichia coli and Pseudomonas aeruginosa. The extrapancreatic infection time (9.1 ± 8.8 d) was earlier than the pancreatic infection time (13.9 ± 12.3 d). Among NP patients with early extrapancreatic infection (< 14 d), bacteremia (25.12%) and respiratory tract infection (21.26%) were predominant. Among NP patients with late extrapancreatic infection (> 14 d), bacteremia (15.94%), respiratory tract infection (7.74%), and urinary tract infection (7.71%) were predominant. Drug sensitivity analysis showed that P. aeruginosa was sensitive to enzymatic penicillins, third- and fourth-generation cephalosporins, and carbapenems. Acinetobacter baumannii and Klebsiella pneumoniae were sensitive only to tigecycline; Staphylococcus epidermidis and Enterococcus faecium were highly sensitive to linezolid, tigecycline, and vancomycin.

CONCLUSION

In this study, we identified the timing, the common species, and site of infection in patients with NP.

Risk factors for intolerance to enteral nutrition in patients with severe acute pancreatitis

AIM

To identify the risk factors for intolerance to enteral nutrition in patients with severe acute pancreatitis (SAP) and provide clinical data for the early clinical application of enteral nutrition in these patients.

METHODS

The clinical data of 243 patients who underwent enteral nutrition treatment for SAP at Tongde Hospital of Zhejiang Province from January 2012 to January 2018 were retrospectively analyzed. According to the presence of intolerance to enteral nutrition or not, the patients were divided into a tolerance group and an intolerance group. The risk factors for intolerance to enteral nutrition were determined by univariate analysis and multivariate logistic regression analysis.

RESULTS

Eight-four (34.57%) of the 243 SAP patients had intolerance to enteral nutrition. Univariate analysis and multivariate logistic regression analysis showed that age > 60 years (OR = 5.212, 95%CI: 1.462-18.587, P = 0.011), fasting time > 72 h (OR = 3.683, 95%CI: 1.322-11.612, P = 0.012), intra-abdominal pressure (IAP) > 20 cmH₂O (OR = 6.034, 95%CI: 2.431-20.114, P = 0.001), acute physiology and chronic health evaluation Ⅱ(APACHE Ⅱ) score > 20 (OR = 6.411, 95%CI: 2.512-22.239, P = 0.001), and serum albumin < 25 g/L (OR = 5.961, 95%CI: 2.318-20.001, P = 0.001) were risk factors for intolerance to enteral nutrition in SAP patients. Adding soluble fiber (OR = 0.221, P = 0.002, 95%CI: 0.067-0.693) was identified to be a protective factor for intolerance to enteral nutrition in SAP patients.

CONCLUSION

The main risk factors for intolerance to enteral nutrition in SAP patients are age > 60 years, fasting time > 72 h, IAP > 20 cmH₂O, APACHE Ⅱ score > 20, and serum albumin < 25 g/L. Soluble fiber diet is able to prevent the development of intolerance to enteral nutrition in SAP patients.

Adaptive Immune Cell Dysregulation and Role in Acute Pancreatitis Disease Progression and Treatment

Acute pancreatitis (AP) is an inflammation of the pancreas caused by various stimuli including excessive alcohol consumption, gallstone disease and certain viral infections. Managing specifically the severe form of AP is limited due to lack of an understanding of the complex immune events that occur during AP involving immune cells and inflammatory molecules such as cytokines. The relative abundance of various immune cells resulting from the immune dysregulation drives disease progression. In this review, we examine the literature on the adaptive immune cells in AP, the prognostic value of these cells in stratifying patients into appropriate care and treatment strategies based on cell frequency in different AP severities are discussed.

Association of Systemic Inflammatory and Anti-inflammatory Responses with Adverse Outcomes in Acute Pancreatitis: Preliminary Results of an Ongoing Study

INTRODUCTION

This paper reports preliminary data of an ongoing study that evaluates the association of systemic inflammatory response (SIRS) with early severe acute pancreatitis (ESAP) and compensatory anti-inflammatory response syndrome (characterized by HLA-DR down-regulation) with infected pancreatic necrosis (IPN).

METHODS

Consecutive patients presenting within 72 h of symptom onset with organ dysfunction and/or local complications were included. Following parameters were recorded: demographics, etiology, SIRS, APACHE II, creatinine, BUN. Circulating IL-8, IL-6, IL-10, TNF-alpha concentrations and expression of HLA-DR and IL-10 by qRT-PCR in PBMCs were measured. Strength of associations of cytokine concentration and HLA-DR/IL-10 expression with outcomes was expressed as Hedges' G and relative risk (95% CI).

RESULTS

Twenty-eight patients (10 MSAP; 18 SAP) fulfilled inclusion criteria. Twelve patients had ESAP and eight presented with organ failure. Admission SIRS worsened in eight (28.6%) patients over 48 h. Sixteen (57.1%) patients developed primary IPN. Twenty-one (75%) patients had HLA-DR down-regulation during the first week, which persisted to the second week in 12 (42.9%) patients. IL-8, IL-6, and TNF-α progressively increased from healthy controls to MAP to MSAP to SAP. IL-6 and TNF-α was higher in the patients who developed ESAP (p = 0.01 and 0.05, respectively). Patients who died within the first week also had a significantly elevated concentration of IL-6 and TNF-α (p = 0.02 and 0.01, respectively). The relative risk (95% CI) of developing primary IPN with persistent HLA-DR down-regulation till the second week of illness was 11.3 (1.6-82.4; p = 0.01).

CONCLUSIONS

Our study objectively demonstrates significant association of ESAP and early mortality with primary cytokine response, and development of IPN with persistent HLA-DR down-regulation.

Increased Circulating CD4+CD25+CD127low/neg Regulatory T-cells as a Prognostic Biomarker in Acute Pancreatitis

OBJECTIVE

Early detection of severe forms with unfavorable outcome is the cornerstone that could provide reduction of morbidity and mortality in acute pancreatitis (AP).

METHODS

The percentage of circulating CD4CD25CD127 regulatory T-cells (Tregs) was determined at admission, on the 48th hour, and on the fifth day in 72 patients with AP. We divided patients in 2 groups-Sev1, which includes 19 patients (26.4%) with moderate AP and 39 patients (54.2%) with mild disease, and Sev2, which includes 14 patients (19.4%) with severe AP. Seven patients (9.7%) developed septic complications. The mortality in our group was 9.7%.

RESULTS

The patients in Sev2 had higher percentage of Tregs at admission and on the fifth day compared with patients in Sev1 (P = 0.007 and P = 0.033, respectively). There was no significant difference in percentage of Tregs at admission, on the 48th hour, and on the fifth day in patients who developed and did not develop infected necrosis (P = 0.50, P = 0.72, and P = 0.92, respectively). Patients with poor outcome had elevated percentage of Tregs on the fifth day (P = 0.045).

CONCLUSIONS

The percentage of circulating Tregs may be implicated in the development of early immune suppression in AP. Elevated percentage of circulating Tregs at admission in AP is an independent prognostic biomarker for severe disease.

sPD-L1 Expression is Associated with Immunosuppression and Infectious Complications in Patients with Acute Pancreatitis

Acute pancreatitis (AP) with infectious complications has high mortality because of early-stage immunosuppression. The programmed cell death-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway is an important host immunosuppression mechanism. Soluble PD-L1 (sPD-L1) expression regulates co-inhibitory signals in malignancies or autoimmune disorders; however, its effects in AP are unknown. Here, we evaluated whether serum sPD-L1 is involved in immune dysfunction and assessed its relationship with infectious complications in early AP. Blood samples were obtained from 56 patients with acute pancreatitis and 21 healthy individuals in this prospective study. Serum sPD-L1 levels within 48 h after AP onset were tested by enzyme-linked immunosorbent assays. Relevant immune parameters (human leucocyte antigen-DR, lymphocyte count) and inflammatory markers (C-reactive protein, white blood cell count) were analysed. sPD-L1 was significantly upregulated in patients with early AP, especially those with infectious complications, compared to healthy controls. Significant negative correlations were observed among monocyte HLA-DR expression, lymphocyte count and sPD-L1 levels in AP. Multivariate regression indicated that sPD-L1 was an independent risk factor for infectious complications in AP. The findings suggest that increased sPD-L1 expression appears to be involved in the development of immunosuppression in the early stage of AP and that sPD-L1 might be an early parameter for prediction of infectious complications in patients with AP.

Dysbiosis of intestinal microbiota and decrease in paneth cell antimicrobial peptide level during acute necrotizing pancreatitis in rats

OBJECTIVES

Intestinal barrier dysfunction plays an important role in acute necrotizing pancreatitis (ANP) and intestinal microbiota dysbiosis was involved in intestinal barrier failure. Paneth cells protect intestinal barrier and are associated with intestinal microbiota. Here, we investigated changes in intestinal microbiota and antimicrobial peptides of Paneth cells in ileum during ANP.

METHODS

Rats with ANP were established by retrograde injection of 3.5% sodium taurocholate into biliopancreatic duct and sacrificed at 24h and 48h, respectively. Injuries of pancreas and distal ileum were evaluated by histopathological score. Intestinal barrier function was assessed by plasma diamine oxidase activity (DAO) and D-lactate. Systemic and intestinal inflammation was evaluated by TNFα, IL-1β and IL-17A concentration by ELISA, respectively. 16S rRNA high throughput sequencing on fecal samples was used to investigate the changes in intestinal microbiota in the ANP group at 48h. Lysozyme and α-defensin5 were measured by real-time PCR, western blot and immunofluoresence.

RESULTS

ANP rats had more severe histopathological injuries in pancreas and distal ileum, injured intestinal barrier and increased expression of TNFα, IL-1β and IL-17A in plasma and distal ileum compared with those of the sham-operated (SO) group. Principal component analysis (PCA) showed structural segregation between the SO and ANP groups. Operational taxonomic unit (OTU) number and ACE index revealed decreased microbiota diversity in the ANP group. Taxonomic analysis showed dysbiosis of intestinal microbiota structure. At phyla level, Saccharibacteria and Tenericutes decreased significantly. At genus level, Escherichia-Shigella and Phascolarctobacterium increased significantly, while Candidatus_Saccharimonas, Prevotellaceae_UCG-001, Lachnospiraceae_UCG-001, Ruminiclostridium_5 and Ruminococcaceae_UCG-008 decreased significantly. Lysozyme and α-defensin5 mRNA expression levels decreased significantly in ANP group at 48h. Protein expression of lysozyme decreased in ANP groups at 24h and 48h. Meanwhile, the relative abundance of Escherichia-Shigella correlated inversely with the decrease in lysozyme.

CONCLUSION

The disorder in intestinal microbiota and decreases of Paneth cell antimicrobial peptides might participate in the pathogenesis of intestinal barrier dysfunction during ANP.

The diffuse reduction in spleen density: an indicator of severe acute pancreatitis?

We observed that acute pancreatitis (AP) was associated with diffuse reduction in spleen density (DROSD) in some patients. Furthermore, the condition of these patients was more serious, and the potential relationship between DROSD and structural and functional injury of the spleen remained unclear. Therefore, we performed a preliminary exploration of these factors. We analysed pertinent clinical data for AP patients with normal spleen density (control group) and for those with DROSD (reduction group) at the First Affiliated Hospital of Harbin Medical University (June 2013–June 2015). We measured the immunoglobulin M (IgM) B-cells of the AP patients and examined pancreatic and splenic tissues from AP rats with optical microscopy and TEM. The reduction group had a higher acute physiology and chronic health evaluation II (APACHE II) score, a longer length of stay (LOS) and lower serum calcium than the control group. The levels of triglycerides (TG) and total cholesterol (TC) did not differ significantly between the two groups. The percentage of IgM memory B-cells was significantly lower in the DROSD group than in the control group. TEM revealed that the spleen T-lymphocytes were normal in AP rats, but pyroptotic and necrotic spleen B-cells were observed in the severe AP rats. In AP, DROSD was an independent indicator of more severe conditions. Furthermore, spleen B-lymphocytes showed obvious damage at the cellular level, and the immunological function of the spleen was down-regulated when AP was associated with DROSD.

Cystathionine-gamma-lyase gene silencing with siRNA in monocytes/macrophages protects mice against acute pancreatitis

Hydrogen sulphide (H2S) is an endogenous inflammatory mediator produced by cystathionine-γ-lyase (CSE) in monocytes/macrophages. To determine the role of H2S and macrophages in inflammation, we used small interference RNA (siRNA) to target the CSE gene and investigated its effect in a mouse model of acute pancreatitis. Acute pancreatitis is characterised by increased levels of plasma amylase, myeloperoxidase (MPO) activity and pro-inflammatory cytokines and chemokines in the pancreas and lung. SiRNA treatment attenuated inflammation in the pancreas and lungs of mice following caerulein-induced acute pancreatitis. MPO activity increased in caerulein-induced acute pancreatitis (16.21 ± 3.571 SD fold increase over control) and treatment with siRNA significantly reduced this (mean 3.555 ± 2.522 SD fold increase over control) (p < 0.0001). Similarly, lung MPO activity increased following treatment with caerulein (3.56 ± 0.941 SD fold increase over control) while siRNA treatment significantly reduced MPO activity (0.8243 ± 0.4353 SD fold increase over control) (p < 0.0001). Caerulein treatment increased plasma amylase activity (7094 ± 207 U/l) and this significantly decreased following siRNA administration (5895 ± 115 U/l) (p < 0.0001). Cytokine and chemokine levels in caerulein-induced acute pancreatitis reduced following treatment with siRNA. For example, siRNA treatment significantly decreased pancreatic and lung monocyte chemoattractant protein (MCP)-1 (169.8 ± 59.75 SD; 90.01 ± 46.97 SD pg/ml, respectively) compared to caerulein-treated mice (324.7 ± 103.9 SD; 222.8 ± 85.37 SD pg/ml, pancreas and lun,g respectively) (p < 0.0001). These findings show a crucial pro-inflammatory role for H2S synthesised by CSE in macrophages in acute pancreatitis and suggest CSE gene silencing with siRNA as a potential therapeutic approach for this condition.

Relationship between the degree of severe acute pancreatitis and patient immunity

PURPOSE

To investigate the relationship between the APACHE II score and the immunity of patients with severe acute pancreatitis.

METHODS

Clinical data were collected from 88 patients with acute pancreatitis, divided into four groups according to the severity of the disease. C-reactive protein (CRP), tumor necrosis factor-α, interleukin-6, interleukin-10, interleukin-4 and endotoxin (ET) in serum were measured on admission and then on days 3, 5, and 7.

RESULTS

The incidence of local complications and multiple organ dysfunction syndrome increased with a higher APACHE II score. The CRP levels were increased significantly on day 3 in all four groups, but remained high only in the extremely severe group. In the mild and moderate groups, the pro-/anti-inflammatory cytokines peaked on day 3 and then decreased slowly. In the severe and extremely severe groups, the proinflammatory cytokines levels peaked on days 3 and 5, and then decreased rapidly. The antiinflammatory cytokines increased progressively on days 3, 5 and 7. The ET levels peaked significantly and then decreased slowly in the mild, moderate and severe groups, but remained high in the extremely severe group.

CONCLUSIONS

An APACHE II score of 16 or higher is predictive of more local and systemic complications, excessive immune response, and premature immunosuppression.