Prophylactic antibiotic treatment is superior to therapy on-demand in experimental necrotising pancreatitis

Usefulness of Bacterial Culture of Drainage Fluid for Predicting Surgical Site Infection After Crohn’s Disease Surgery

Aim

Methods

Results

Conclusion

A Randomized Phase II Study to Evaluate Prolonged Prophylactic Antibacterial Drug Treatment for Patients with Elevated Drain Amylase Concentration After Gastrectomy with D2 Lymph Node Dissection (REDUCED2)

INTRODUCTION

After D2 gastrectomy for advanced gastric cancer, patients with a high drainage fluid amylase level (d-AMY) on the first postoperative day (1POD) have an especially high risk of severe abdominal infectious complications (AICs), which could be fatal. On the hypothesis that prolonged antibiotic administration could reduce the incidence of severe AICs, we conducted a randomized phase II study to evaluate the optimal treatment duration of prophylactic antibiotics for patients who underwent D2 gastrectomy and had elevated d-AMY on 1POD.

METHODS

Patients whose d-AMY was >3000 IU/L on 1POD after D2 gastrectomy for gastric cancer were randomly assigned to normal prophylactic antibiotic treatment given only on the day of surgery (Group A) or to prolonged antibiotic treatment given for 1 week after surgery (Group B). The primary endpoint was the incidence of severe AICs (Clavien-Dindo grade IIIa or higher). This trial was registered as UMIN000012152.

RESULTS

This study was started in December 2013 and stopped in February 2019 because of poor patient accrual. Finally, 35 and 37 patients were assigned to groups A and B, respectively. The incidences of AICs were 22.9% (eight of 35) in group A and 13.5% (five of 37) in group B. One-sided P value of the Fisher exact test was 0.234. No adverse reactions to antibiotic prophylaxis were observed in any of the patients.

CONCLUSIONS

Prolonged prophylactic antibiotic administration had a marginal benefit in preventing grade III or higher AICs and caused no treatment-related morbidities.

NLRP3 Inflammasome-Mediated Inflammation in Acute Pancreatitis

The discovery of inflammasomes has enriched our knowledge in the pathogenesis of multiple inflammatory diseases. The NLR pyrin domain-containing protein 3 (NLRP3) has emerged as the most versatile and well-characterized inflammasome, consisting of an intracellular multi-protein complex that acts as a central driver of inflammation. Its activation depends on a tightly regulated two-step process, which includes a wide variety of unrelated stimuli. It is therefore not surprising that the specific regulatory mechanisms of NLRP3 inflammasome activation remain unclear. Inflammasome-mediated inflammation has become increasingly important in acute pancreatitis, an inflammatory disorder of the pancreas that is one of the fatal diseases of the gastrointestinal tract. This review presents an update on the progress of research into the contribution of the NLRP3 inflammasome to acute pancreatic injury, examining the mechanisms of NLRP3 activation by multiple signaling events, the downstream interleukin 1 family of cytokines involved and the current state of the literature on NLRP3 inflammasome-specific inhibitors.

Two-point measurement of amylase in drainage fluid predicts severe postoperative pancreatic fistula after gastric cancer surgery

BACKGROUND

Early identification of patients at risk of postoperative pancreatic fistula (POPF) allows appropriate management after gastrectomy. Although some reports have suggested a correlation between POPF and the concentration of amylase in drained abdominal fluid (D-AMY), this has not been proven to impact sufficiently on clinical decision-making. A sustained high level of D-AMY is often assumed to be due to unsatisfactory drainage or excessive pancreatic leakage. We assessed the clinical utility of measuring D-AMY on postoperative day (POD) 1 and POD3 for prediction of POPF.

METHODS

Starting in April 2014, 801 patients who underwent radical gastrectomy with prophylactic drain placement were consecutively enrolled. We routinely measured D-AMY on POD1 and POD3, and compared the incidence of problematic POPF and clinical factors including D-AMY. We also attempted to clarify whether such two-point D-AMY measurement was clinically useful for patient management after gastrectomy.

RESULTS

Fifty-one of the patients (6.4%) developed Clavien-Dindo grade III or worse POPF. Using D-AMY cutoffs of 2218 IU/L on POD1 and 555 IU/L on POD3, the patients were successfully classified. The highest risk group, in which D-AMY was higher than the cut-off value on both POD1 and POD3, showed a significantly high rate of occurrence (33/105, 31.4%) and high positive likelihood ratio (6.74). Multivariate analysis showed that classification into this highest risk group was an independent risk factor for development of severe POPF (odds ratio 15.2, 95% CI 7.92-29.0).

CONCLUSION

Two-point measurement of D-AMY may be an efficient tool for achieving individualized management of POPF following radical gastrectomy.

Antibiotic-Induced Pathobiont Dissemination Accelerates Mortality in Severe Experimental Pancreatitis

Although antibiotic-induced dysbiosis has been demonstrated to exacerbate intestinal inflammation, it has been suggested that antibiotic prophylaxis may be beneficial in certain clinical conditions such as acute pancreatitis (AP). However, whether broad-spectrum antibiotics, such as meropenem, influence the dissemination of multidrug-resistant (MDR) bacteria during severe AP has not been addressed. In the currently study, a mouse model of obstructive severe AP was employed to investigate the effects of pretreatment with meropenem on bacteria spreading and disease outcome. As expected, animals subjected to biliopancreatic duct obstruction developed severe AP. Surprisingly, pretreatment with meropenem accelerated the mortality of AP mice (survival median of 2 days) when compared to saline-pretreated AP mice (survival median of 7 days). Early mortality was associated with the translocation of MDR strains, mainly Enterococcus gallinarum into the blood stream. Induction of AP in mice with guts that were enriched with E. gallinarum recapitulated the increased mortality rate observed in the meropenem-pretreated AP mice. Furthermore, naïve mice challenged with a mouse or a clinical strain of E. gallinarum succumbed to infection through a mechanism involving toll-like receptor-2. These results confirm that broad-spectrum antibiotics may lead to indirect detrimental effects during inflammatory disease and reveal an intestinal pathobiont that is associated with the meropenem pretreatment during obstructive AP in mice.

Immunopathogenesis of pancreatitis

The conventional view of the pathogenesis of acute and chronic pancreatitis is that it is due to a genetic- or environment-based abnormality of intracellular acinar trypsinogen activation and thus to the induction of acinar cell injury that, in turn, sets in motion an intra-pancreatic inflammatory process. More recent studies, reviewed here, present strong evidence that while such trypsinogen activation is likely a necessary first step in the inflammatory cascade underlying pancreatitis, sustained pancreatic inflammation is dependent on damage-associated molecular patterns-mediated cytokine activation causing the translocation of commensal (gut) organisms into the circulation and their induction of innate immune responses in acinar cells. Quite unexpectedly, these recent studies reveal that the innate responses involve activation of responses by an innate factor, nucleotide-binding oligomerization domain 1 (NOD1), and that such NOD1 responses have a critical role in the activation/production of nuclear factor-kappa B and type I interferon. In addition, they reveal that chronic inflammation and its accompanying fibrosis are dependent on the generation of IL-33 by injured acinar cells and its downstream induction of T cells producing IL-13. These recent studies thus establish that pancreatitis is quite a unique form of inflammation and one susceptible to newer, more innovative therapy.

Nucleotide-binding oligomerization domain 1 and gastrointestinal disorders

Nucleotide-binding oligomerization domain 1 (NOD1) is an intracellular sensor that detects small peptides derived from the cell wall component of intestinal microflora. NOD1 is expressed in both non-hematopoietic cells such as epithelial cells and hematopoietic cells such as antigen-presenting cells. Detection of its ligand by NOD1 leads to innate immune responses through activation of nuclear factor kappa B and type I interferon as well as induction of autophagy. Innate immune responses through NOD1 activation play an indispensable role both in host defense against microbial infection and in the development of gastrointestinal disorders. Of particular importance, NOD1-mediated innate immune responses are associated with mucosal host defenses against Helicobacter pylori (H. pylori) infection of the stomach and with the development of pancreatitis. In this review, we discuss the molecular mechanisms by which NOD1 activation leads to the development of H. pylori-related gastric diseases and pancreatitis.

Paeoniflorin ameliorates acute necrotizing pancreatitis and pancreatitis‑induced acute renal injury

Acute renal injury caused by acute necrotizing pancreatitis (ANP) is a common complication that is associated with a high rate of mortality. Paeoniflorin is the active ingredient of paeonia radix and exhibits a number of pharmacological effects, such as anti-inflammatory, anticancer, analgesic and immunomodulatory effects. The present study detected the potential treatment effects of paeoniflorin on acute renal injury induced by ANP in a rat model. The optimal dose of paeoniflorin for preventing acute renal injury induced by ANP was determined. Then, the possible protective mechanism of paeoniflorin was investigated. The serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were measured with enzyme-linked immunosorbent assay kits. Renal inflammation and apoptosis were measured by immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. The expression of nitric oxide in kidney tissues was also evaluated. The p38 mitogen-activated protein kinases (MAPKs) were measured by western blotting. The results shown that paeoniflorin may ameliorate acute renal injury following ANP in rats by inhibiting inflammatory responses and renal cell apoptosis. These effects may be associated with the p38MAPK and nuclear factor-κB signal pathway.

Enzymatic debridement in necrotizing pancreatitis

Multiple organ failure and pancreatic necrosis are the factors that determine prognosis in acute pancreatitis attacks. We investigated the effects of collagenase on the debridement of experimental pancreatic necrosis. The study covered 4 groups; each group had 10 rats. Group I was the necrotizing pancreatitis group. Group II was the collagenase group with pancreatic loge by isotonic irrigation following necrotizing pancreatitis. Group III was the collagenase group with pancreatic loge following necrotizing pancreatitis. Group IV was the intraperitoneal collagenase group following necrotizing pancreatitis. The progress of the groups was compared hematologically and histopathologically. There was no difference among the groups regarding the levels of leukocyte, hemogram, and urea. The differences in AST levels between Group I and II; and differences in glucose, calcium, LDH, AST, and amylase between Group II and III; between Group II and IV; between Group I and III; and between Group I and IV were statistically significant (P < 0.05). There were statistically significant differences between Group II and III, and Group II and IV regarding edema, acinar necrosis, inflammatory cell infiltration, hemorrhage, and fat necrosis (P < 0.05). In conclusion, the collagenase preparation used in this experimental pancreatitis model was found to be effective in the debridement of pancreatic necrosis.

Effect of octreotide on enteric motor neurons in experimental acute necrotizing pancreatitis

Background/Aims

Amelioration of intestinal dysmotility and stasis during the early period of acute necrotizing pancreatitis (ANP) appears to be important to reduce the risks of secondary pancreatic infection. We aimed to characterize the association between the neuropathy of the enteric nervous system and gut dysfunction and to examine the effect of octreotide on motor innervation in the early stage of ANP.

Methodology/Principal Findings

The rats were randomly divided into eight groups: control+saline; control+octreotide; ANP+saline and ANP+octreotide (24 h, 48 h, 72 h). The spontaneous activity of ileal segments and the response to ACh, l-NNA were recorded. The alterations of myenteric neuronal nitric oxide synthase (nNOS), choline acetyltransferase (CHAT), PGP9.5 and somatostatin receptor 2 (SSTR₂) immunoreactive cells were evaluated by immunofluorescence and the protein expression of nNOS and CHAT were evaluated by western blot. We found the amplitude of spontaneous contractions at 48 h and the response to ACh at 24 h declined in the ANP+saline rats. A higher contractile response to both ACh and to l-NNA was observed in the ANP+octreotide group, compared with the ANP+saline rats at 24 h. A significant reduction in the nNOS and cholinergic neurons was observed in ANP+saline rats at the three time points. However, this reduction was greatly ameliorated in the presence of octreotide at 24 h and 48 h. The protein expression of CHAT neurons at 24 h and the nNOS neurons at 48 h in the ANP+octreotide rats was much higher than the ANP+saline rats.

Conclusion

The pathogenesis of ileus in the early stage of ANP may be related to the neuropathy of the enteric nervous system. Octreotide may reduce the severity of ileus by lessening the damage to enteric motor innervation.

Effects of prophylactic antibiotics in acute pancreatitis

OBJECTIVES

The use of prophylactic antibiotics in severe acute pancreatitis (SAP) is controversial. The aim of this study was to compare the effects of antibiotics administered as prophylaxis and as treatment on demand, respectively, in two prospective, non-randomized cohorts of patients.

METHODS

The study population consisted of 210 patients treated for SAP. In Group 1 (n= 103), patients received prophylactic antibiotics (ciprofloxacin, metronidazole). In Group 2 (n= 107), patients were treated on demand. Ultrasound-guided drainage and/or surgical debridement of infected necrosis were performed when the presence of infected pancreatic necrosis was demonstrated. The primary endpoints were infectious complication rate, need for and timing of surgical interventions, incidence of nosocomial infections and mortality rate.

RESULTS

Ultrasound-guided fine needle aspiration [in 18 (16.8%) vs. 13 (12.6%) patients; P= 0.714], ultrasound-guided drainage [in 15 (14.0%) vs. six (5.8%) patients; P= 0.065] and open surgical necrosectomy [in 10 (9.3%) vs. five (4.9%) patients; P= 0.206] were performed more frequently and earlier [at 16.6 ± 7.8 days vs. 17.2 ± 6.7 days (P= 0.723); at 19.5 ± 9.4 days vs. 24.5 ± 14.2 days (P= 0.498), and at 22.6 ± 13.5 days vs. 26.7 ± 18.1 days (P= 0.826), respectively] in Group 2 compared with Group 1. There were no significant differences between groups in mortality and duration of stay in the surgical ward or intensive care unit.

CONCLUSIONS

The results of this study support the suggestion that the use of prophylactic antibiotics does not affect mortality rate, but may decrease the need for interventional and surgical management, and lower the number of reoperations.

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.

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.

Medical treatment of severe acute pancreatitis with multiple organ dysfunction syndrome

Severe acute pancreatitis (SAP) is one of the crucial acute abdominal diseases. Multiple organ dysfunction syndromes (MODS) is the main cause of death in SAP patients. The medical treatment measures include the fundamental cure such as fluid resuscitation, correction of the internal environment disorder and hyoxemia, and preferred application of somatostatin, adequate use of trypsin inhibitors, antibiotics and early enteral nutrition. In addition, immunomodulation, antioxidants, blood purification and endoscopic interventional therapy may be selective to improve the prognosis of SAP.

A role for prophylactic antibiotics in necrotizing pancreatitis? Why we may never know the answer

The use of prophylactic antibiotics in patients with severe acute pancreatitis remains an intensely debated topic. Although animal studies consistently demonstrated an advantage of antibiotic prophylaxis, the only two blinded randomized controlled trials could not confirm these findings. Translation of the experimental models in human clinical practice is hampered by a number of fundamental differences between experimental pancreatitis and human disease, and therefore it is highly unlikely that the pronounced benefit found in experimental pancreatitis will ever be demonstrated in human disease. Early and accurate risk stratification to identify the patient at risk for infection early in the course of the disease seems to be the greatest challenge. Until we are able to demonstrate an advantage of antibiotic prophylaxis in a high-risk human population, the absence of proven benefit and potential side effects of this strategy should be acknowledged and the use of antibiotics should be limited to the treatment of documented infection.