Blood-pancreatic juice barrier to antibiotic excretion

Selective and Concentrative Enteropancreatic Recirculation of Antibiotics by Pigs

Antibiotics that are efficacious for infectious pancreatitis are present in pancreatic exocrine secretion (PES) after intravenous administration and above minimal inhibitory concentrations. We measured concentrations of four antibiotics by tandem liquid chromatography-mass spectroscopy in plasma and PES after enteral administration to juvenile pigs with jugular catheters and re-entrant pancreatic-duodenal catheters. Nystatin, which is not absorbed by the intestine nor used for infectious pancreatitis (negative control), was not detected in plasma or PES. Concentrations of amoxicillin increased in plasma after administration (p = 0.035), but not in PES (p = 0.51). Metronidazole and enrofloxacin that are used for infectious pancreatitis increased in plasma after enteral administration and even more so in PES, with concentrations in PES averaging 3.1 (±0.5)- and 2.3 (±0.6)-fold higher than in plasma, respectively (p's < 0.001). The increase in enrofloxacin in PES relative to plasma was lower after intramuscular administration (1.8 ± 0.5; p = 0.001). The present results demonstrate the presence of a selective and concentrative enteropancreatic pathway of secretion for some antibiotics. Unlike the regulated secretion of bile, the constitutive secretion of PES and intestinal reabsorption may provide a continuous exposure of pancreas tissue and the small intestine to recirculated antibiotics and potentially other therapeutic molecules. There is a need to better understand the enteropancreatic recirculation of antibiotics and the associated mechanisms.

Combining nanotechnology with the multifunctional roles of neutrophils against cancer and inflammatory disease

Neutrophils, the most abundant leukocytes in humans, play a crucial role in acute inflammation during infection and tumorigenesis. Neutrophils are the major types of cells recruited to the inflammation sites induced by pathogens, exhibiting great homing ability towards inflammatory disorders and tumor sites. Therefore, a neutrophil-based drug delivery system (NDDS) has become a promising platform for anti-cancer and anti-inflammatory treatment. Recent decades have witnessed the huge progress of applying nanomaterials in drug delivery. Nanomaterials are regarded as innovative components to enrich the field of neutrophil-based therapies due to their unique physiochemical characteristics. In this review, the latest advancement of combining diverse nanomaterials with an NDDS for cancer and inflammatory disease treatment will be summarized. It is discussed how nanomaterials empower the therapeutic area of an NDDS and how an NDDS circumvents the limitations of nanomaterials. Moreover, based on the finding that neutrophils are closely involved in the progression of cancer and inflammatory diseases, emerging therapeutic strategies that target neutrophils will be outlined. Finally, as neutrophils were demonstrated to play a central role in the immunopathology of COVID-19, which causes necroinflammation that is responsible for the cytokine storm and sepsis during coronavirus infections, novel therapeutic approaches that anchor neutrophils against the pathological consequences related to COVID-19 will be highlighted as well.

Good abdominal drainage fluid penetration and pharmacokinetics analysis of vancomycin for severe acute pancreatitis: A case report

WHAT IS KNOWN AND OBJECTIVE

The antibiotic concentration in abdominal drainage fluid is very important for the treatment of patients with severe acute pancreatitis (SAP). Previous studies show that quinolones and carbapenems have high abdominal tissue levels, whereas aminoglycosides fail to penetrate into abdominal tissue in sufficient concentrations. However, there are limited data with respect to vancomycin. This case aims to investigate the penetration of vancomycin to abdominal drainage fluid in a 44-year-old SAP patient.

CASE SUMMARY

We report a case of a 44-year-old female with SAP, on treatment of vancomycin. The time courses of vancomycin concentration in plasma and abdominal drainage fluid of the patient were described. Simultaneous measurement of abdominal drainage fluid and serum concentrations demonstrated that vancomycin can rapidly penetrate into abdominal tissue in acceptable amounts.

WHAT IS NEW AND CONCLUSION

This case demonstrated that it took about 30 minutes for vancomycin to get from plasma to abdominal drainage fluid and about 76% of vancomycin could move into abdominal drainage fluid for SAP patients.

Rethinking Carbapenems: A Pharmacokinetic Approach for Antimicrobial Selection in Infected Necrotizing Pancreatitis

OBJECTIVE

To provide an overview of pathophysiological changes to the pancreas during infected necrotizing pancreatitis (INP), optimal drug properties needed to penetrate the pancreas, human and animal studies supporting the use of antimicrobials, and carbapenem-sparing strategies in INP.

DATA SOURCES

A literature analysis of PubMed/MEDLINE was performed (from 1960 to September 2020) using the following key terms: infected necrotizing pancreatitis, necrotizing acute pancreatitis, and infected pancreatitis antimicrobial concentration. Individual antimicrobials were investigated with these search terms.

STUDY SELECTION AND DATA EXTRACTION

All relevant studies describing the management of INP, and human and animal pharmacokinetic (PK) data supporting antimicrobial use in the pancreas were reviewed for possible inclusion regardless of sample size or study design.

DATA SYNTHESIS

Piperacillin/tazobactam and cefepime achieve adequate pancreatic tissue concentrations in INP studies. A majority of the literature supporting carbapenem use in INP involves imipenem, and meropenem Monte Carlo simulations suggest that standard dosing regimens of meropenem may not achieve PK targets to eradicate Pseudomonas aeruginosa.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Carbapenems are often utilized for INP treatment based on guideline recommendations. This review discusses PK data, the history of carbapenem use in INP, and the pathophysiology of pancreatitis to suggest carbapenem-sparing strategies and provides stewardship tactics such as when to start antimicrobials, which empirical antimicrobial to use, and when to discontinue antimicrobials in the INP setting.

CONCLUSIONS

Noncarbapenem antipseudomonals, such as piperacillin/tazobactam and cefepime, are appropriate carbapenem-sparing options in INP, based on PK data, spectrum of activity, and risk of collateral damage.

Enhancement of Antitumor Efficacy of Paclitaxel-Loaded PEGylated Liposomes by N,N-Dimethyl Tertiary Amino Moiety in Pancreatic Cancer

Introduction

Pancreatic cancer, or pancreatic duct adenocarcinoma (PDAC), remains one of the most lethal cancers and features insidious onset, highly aggressive behavior and early distant metastasis. The dense fibrotic stroma surrounding tumor cells is thought to be a shield to resist the permeation of chemotherapy drugs in the treatment of PDAC. Thus, we synthesized a pancreas-targeting paclitaxel-loaded PEGylated liposome and investigated its antitumor efficacy in the patient-derived orthotopic xenograft (PDOX) nude mouse models of PDAC.

Methods

The PTX-loaded PEGylated liposomes were prepared by film dispersion-ultrasonic method and modified by an N,N-dimethyl tertiary amino residue. Morphology characteristics of the PTX-loaded liposomes were observed by transmission electron microscope (TEM). The PDOX models of PDAC were established by orthotopic implantation and imaged by a micro positron emission tomography/computed tomography (PET/CT) imaging system. The in vivo distribution and antitumor study were then carried out to observe the pancreas-targeting accumulation and the antitumor efficacy of the proposed PTX liposomes.

Results

PTX loaded well into both modified (PTX-Lip2N) and unmodified (PTX-Lip) PEGylated liposomes with spherical shapes and suitable parameters for the endocytosis process. The PDOX nude mouse models were successfully created in which high ¹⁸F-FDG intaking regions were observed by micro-PET/CT. In addition to higher cellular uptakes of PTX-Lip2N by the BxPC-3 cells, the proposed nanoparticle had a notable penetrating ability towards PDAC tumor tissues, and consequently, the antitumor ability of PTX-Lip2N was significantly superior to the unmodified PTX-Lip in vivo PDOX models and even more effective than nab-PTX in restraining tumor growth.

Conclusion

The modified pancreas-targeting PTX-loaded PEGylated liposomes provide a promising platform for the treatment of pancreatic cancer.

N,N-Dimethyl Tertiary Amino Group Mediated Dual Pancreas- and Lung-Targeting Therapy against Acute Pancreatitis

Acute pancreatitis (AP) is a sudden inflammation of the pancreas with high mortality rate worldwide. As a severe complication to AP, acute lung injury has been the major cause of death among patients with AP. Poor penetration across the blood pancreas barrier (BPB) and insufficient drug accumulation at the target site often result in poor therapeutic outcome. Our previous work successfully demonstrated a dual-specific targeting strategy to pancreas and lung using a phenolic propanediamine moiety. Inspired by this, a simplified ligand structure, N,N-dimethyl tertiary amino group, was covalently conjugated to celastrol (CLT) to afford tertiary amino conjugates via either an ester (CP) or an amide linkage (CTA). With sufficient plasma stability, CTA was subjected to the following studies. Compared to CLT, CTA exhibited excellent cellular uptake efficiency in both rat pancreatic acinar cell line (AR42J) and human pulmonary alveolar epithelial cell line (A549). Organic cation transporters were proven to be responsible for this active transport process. Given systemically, CTA specifically distributed to pancreases and lungs in rats thus resulting in a 2.59-fold and 3.31-fold increase in tissue-specific accumulation as compared to CLT. After CTA treatment, tissue lesions were greatly alleviated and the levels of proinflammatory cytokines were downregulated in rats with sodium taurocholate induced AP. Furthermore, CTA demonstrated marginal adverse effect against major organs with reduced cardiac toxicity compared to CLT. Together, tertiary amine mediated dual pancreas- and lung-targeting therapy represents an efficient and safe strategy for AP management.

Pharmacokinetics and pharmacodynamics of Da-Cheng-Qi decoction in the liver of rats with severe acute pancreatitis

AIM

To explore the pharmacokinetics and pharmacodynamics of Da-Cheng-Qi decoction (DCQD) in the liver of rats with severe acute pancreatitis (SAP) based on an herbal recipe tissue pharmacology hypothesis.

METHODS

Healthy male Sprague-Dawley rats were randomly divided into a sham operation group (SOG); a model group (MG); and low-, median- and high-dose treatment groups (LDG, MDG, and HDG, respectively). Different dosages (6, 12 and 24 g/kg for the LDG, MDG, and HDG, respectively) of DCQD were administered to the rats with SAP. The tissue concentrations of aloe-emodin, rhein, emodin, chrysophanol, honokiol, rheo chrysophanol, magnolol, hesperidin, naringenin and naringin in the liver of the treated rats were detected by high-performance liquid chromatography tandem mass spectrometry. Alanine transaminase (ALT) and aspartate transaminase (AST) in serum, inflammatory mediators in the liver and pathological scores were evaluated.

RESULTS

The major components of DCQD were detected in the liver, and their concentrations increased dose-dependently. The high dose of DCQD showed a maximal effect in ameliorating the pathological damages, decreasing the pro-inflammatory mediators tumor necrosis factor-α and interleukin (IL)-6 and increasing anti-inflammatory mediators IL-4 and IL-10 in the liver. The pathological scores in the pancreas for the MG were significantly higher than those for the SOG (P < 0.05). DCQD could reduce the pathological scores in the pancreas and liver of the rats with SAP, especially in the HDG. Compared to the SOG, the ALT and AST levels in serum were higher in the MG (P < 0.05), while there was no statistical difference in the MG and HDG.

CONCLUSION

DCQD could alleviate liver damage by altering the inflammatory response in rats with SAP based on the liver distribution of its components.

Tissue Pharmacology of Da-Cheng-Qi Decoction in Experimental Acute Pancreatitis in Rats

Objectives. The Chinese herbal medicine Da-Cheng-Qi Decoction (DCQD) can ameliorate the severity of acute pancreatitis (AP). However, the potential pharmacological mechanism remains unclear. This study explored the potential effective components and the pharmacokinetic characteristics of DCQD in target tissue in experimental acute pancreatitis in rats. Methods. Acute pancreatitis-like symptoms were first induced in rats and then they were given different doses of DCQD (6 g/kg, 12 g/kg, and 24 g/kg body weight) orally. Tissue drug concentration, tissue pathological score, and inflammatory mediators in pancreas, intestine, and lung tissues of rats were examined after 24 hours, respectively. Results. Major components of DCQD could be found in target tissues and their concentrations increased in conjunction with the intake dose of DCQD. The high-dose compounds showed maximal effect on altering levels of anti-inflammatory (interleukin-4 and interleukin-10) and proinflammatory markers (tumor necrosis factor α and interleukin-6) and ameliorating the pathological damage in target tissues (P < 0.05). Conclusions. DCQD could alleviate pancreatic, intestinal, and lung injury by altering levels of inflammatory cytokines in AP rats with tissue distribution of its components.

Dual pancreas- and lung-targeting therapy for local and systemic complications of acute pancreatitis mediated by a phenolic propanediamine moiety

To inhibit both the local and systemic complications with acute pancreatitis, an effective therapy requires a drug delivery system that can efficiently overcome the blood-pancreas barrier while achieving lung-specific accumulation. Here, we report the first dual pancreas- and lung-targeting therapeutic strategy mediated by a phenolic propanediamine moiety for the treatment of acute pancreatitis. Using the proposed dual-targeting ligand, an anti-inflammatory compound Rhein has been tailored to preferentially accumulate in the pancreas and lungs with rapid distribution kinetics, excellent tissue-penetrating properties and minimum toxicity. Accordingly, the drug-ligand conjugate remarkably downregulated the proinflammatory cytokines in the target organs thus effectively inhibiting local pancreatic and systemic inflammation in rats. The dual-specific targeting therapeutic strategy may help pave the way for targeted drug delivery to treat complicated inflammatory diseases.

Dissecting the effect of moxifloxacin in mice with infected necrosis in taurocholate induced necrotizing pancreatitis

OBJECTIVES

To investigate the limited benefit of antibiotics in ameliorating the outcome of acute necrotizing pancreatitis, we analyzed antibiotic therapy in primarily infected necrotizing pancreatitis in mice with respect to the local pancreatic pathology as well as systemic, pancreatitis induced adverse events.

METHODS

Sterile pancreatic necrosis (SN) was induced by retrograde injection of 4% taurocholate in the common bile duct of Balb/c mice. Primarily infected pancreatic necrosis (IN) was induced by co-injecting 10(8) CFU/ml Escherichia coli. 10 mg/kg of moxifloxacin was administered prior to pancreatitis induction (AN). After 24 h, animals were sacrificed to examine serum as well as organs for signs of SIRS.

RESULTS

Moxifloxacin significantly reduced bacterial count in pancreatic lysates of animals with infected pancreatic necrosis (IN 4.1·10(7) ± 2.4·10(7) vs. AN 4.9·10(4) ± 2.6·10(4) CFU/g; p < 0.001). However, it did not alter pancreatic histology or pulmonary damage (Histology score: IN 23.8 ± 2.7 vs. AN 22.6 ± 1.7). Moxifloxacin reduced systemic immunoactivation (Serum IL-6: IN 330.5 ± 336.6 vs. 38.7 ± 25.5 pg/ml; p < 0.001), hypoglycemia (serum glucose: IN 105.8 ± 12.7 vs. AN 155.7 ± 39.5 mg/dl; p < 0.001), and serum aspartate aminotransferase (IN 606 ± 89.7 vs. AN 255 ± 52.1; p < 0.05). These parameters were significantly increased in animals with necrotizing pancreatitis.

CONCLUSION

In the experimental setting, initial antibiotic therapy with moxifloxacin in acute infected necrotizing pancreatitis in mice does not have a beneficial impact on pancreatic pathology or pulmonary damage. However, other systemic complications induced by infected necrosis in acute pancreatitis are reduced by the administration of moxifloxacin.

Antibiotic therapy for prophylaxis against infection of pancreatic necrosis in acute pancreatitis

BACKGROUND

Pancreatic necrosis may complicate severe acute pancreatitis, and is detectable by computed tomography (CT). If it becomes infected mortality increases, but the use of prophylactic antibiotics raises concerns about antibiotic resistance and fungal infection.

OBJECTIVES

To determine the efficacy and safety of prophylactic antibiotics in acute pancreatitis complicated by CT proven pancreatic necrosis.

SEARCH STRATEGY

Searches were updated in November 2008, in The Cochrane Library (Issue 2, 2008), MEDLINE, EMBASE, and CINAHL. Conference proceedings and references from found articles were also searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing antibiotics versus placebo in acute pancreatitis with CT proven necrosis.

DATA COLLECTION AND ANALYSIS

Primary outcomes were mortality and pancreatic infection rates. Secondary end-points included non pancreatic infection, all sites infection, operative rates, fungal infections, and antibiotic resistance. Subgroup analyses were performed for antibiotic regimen (beta-lactam, quinolone, and imipenem).

MAIN RESULTS

Seven evaluable studies randomised 404 patients. There was no statistically significant effect on reduction of mortality with therapy: 8.4% versus controls 14.4%, and infected pancreatic necrosis rates: 19.7% versus controls 24.4%. Non-pancreatic infection rates and the incidence of overall infections were not significantly reduced with antibiotics: 23.7% versus 36%; 37.5% versus 51.9% respectively. Operative treatment and fungal infections were not significantly different. Insufficient data were provided concerning antibiotic resistance.With beta-lactam antibiotic prophylaxis there was less mortality (9.4% treatment, 15% controls), and less infected pancreatic necrosis (16.8% treatment group, 24.2% controls) but this was not statistically significant. The incidence of non-pancreatic infections was non-significantly different (21% versus 32.5%), as was the incidence of overall infections (34.4% versus 52.8%), and operative treatment rates. No significant differences were seen with quinolone plus imidazole in any of the end points measured. Imipenem on its own showed no difference in the incidence of mortality, but there was a significant reduction in the rate of pancreatic infection (p=0.02; RR 0.34, 95% CI 0.13 to 0.84).

AUTHORS' CONCLUSIONS

No benefit of antibiotics in preventing infection of pancreatic necrosis or mortality was found, except for when imipenem (a beta-lactam) was considered on its own, where a significantly decrease in pancreatic infection was found. None of the studies included in this review were adequately powered. Further better designed studies are needed if the use of antibiotic prophylaxis is to be recommended.

Effects of Chai-Qin-Cheng-Qi Decoction on cefotaxime in rats with acute necrotizing pancreatitis

AIM: To investigate the effect of Chai-Qin-Cheng-Qi Decoction (CQCQD) on cefotaxime (CTX) concentration in pancreas of rats with acute necrotizing pancreatitis (ANP).

METHODS: Sixty healthy male Sprague-Dawley rats were divided randomly into an ANP group (ANP model + CTX, n = 20), treatment group (ANP model + CTX + CQCQD, n = 20) and control group (normal rats + CTX, n = 20). ANP models were induced by retrograde intraductal injection of 3.5% sodium taurocholate (1 mL/kg), and the control group was injected intraductally with normal saline. All rats were injected introperitoneally with 0.42 g/kg CTX (at 12-h intervals for a continuous 72 h) at 6 h after intraductal injection. Meanwhile, the treatment group received CQCQD (20 mL/kg) intragastrically at 8-h intervals, and the ANP and control group were treated intragastrically with normal saline. At 15 min after the last CTX injection, blood and pancreas samples were collected for the determination of CTX concentration using validated high-performance liquid chromatography. Pathological changes and wet-to-dry-weight (W/D) ratio of pancreatic tissue were examined.

RESULTS: Serum CTX concentrations in three groups were not significantly different. Pancreatic CTX concentration and penetration ratio were lower in ANP group vs control group (4.4 ± 0.6 μg/mL vs 18.6 ± 1.7 μg/mL, P = 0.000; 5% vs 19%, P = 0.000), but significantly higher in treatment group vs ANP group (6.4 ± 1.7 μg/mL vs 4.4 ± 0.6 μg/mL, P = 0.020; 7% vs 5%, P = 0.048). The histological scores and W/D ratio were significantly decreased in treatment group vs ANP and control group.

CONCLUSION: CQCQD might have a promotive effect on CTX concentration in pancreatic tissues of rats with ANP.

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

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

Antibiotic therapy for prophylaxis against infection of pancreatic necrosis in acute pancreatitis

BACKGROUND

Acute pancreatitis is a common abdominal emergency with no specific treatment. Pancreatic necrosis may complicate severe attacks, detectable by computed tomography (CT). Necrosis can become infected, making surgical intervention necessary and increasing mortality to more than 40%. Experimental studies suggest that antibiotic therapy may prevent infection, but could promote resistance and fungal infection.

OBJECTIVES

To determine the effectiveness and safety of prophylactic antibiotics in acute pancreatitis complicated by pancreatic necrosis.

SEARCH STRATEGY

The Cochrane Library (Issue 1, 2006), MEDLINE (January 1966-December 2005), EMBASE (January 1980-December 2005) and CINAHL (January 1982-December 2005) were searched. We also examined Conference proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing antibiotics versus placebo in acute pancreatitis with CT proven necrosis were sought using a detailed search strategy without linguistic limitation. RCTs. Initial searching was undertaken in November 2001. Latest update: December 2005.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently for rates of primary end-points: mortality and pancreatic infection rates. Secondary end-points included: non pancreatic infection and operative rates. Adverse events: antibiotic resistance and fungal infections. Subgroup analyses: antibiotic regimen.

MAIN RESULTS

Five evaluable studies randomised 294 patients. Analysis suggested significantly less mortality with therapy (6%) versus controls (15.3%), odds ratio 0.37 (95% CI 0.17, 0.83). Infected pancreatic necrosis rates were not significantly different (therapy 20%, controls 27.8%), odds ratio 0.62 (95% CI 0.35, 1.09), and neither were operative treatment rates or non-pancreatic infection rates. Fungal infections were not significantly different at 4% with therapy versus 4.9% in controls, odds ratio 0.83 (95% CI 0.30, 2.27). There were no evaluable data on antibiotic resistance. Sub-group analysis was performed for antibiotic regimen: beta lactam (192 patients), and quinolone plus imidazole (102 patients). With beta lactam prophylaxis there was significantly less mortality (6.3%) versus controls (16.7%), odds ratio 0.34 (95% CI 0.13, 0.91), and infected pancreatic necrosis (15.6%) versus (29.2%) in controls, odds ratio 0.41 (95% CI 0.20, 0.85), but there were no significant differences in operative treatment rates or non-pancreatic infections. No significant differences were seen with quinolone plus imidazole.

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis appeared to be associated with significantly decreased mortality but not infected pancreatic necrosis. Beta lactams were associated with significantly decreased mortality and infected pancreatic necrosis, but quinolone plus imidazole regimens were not. There were variations in methodological quality, treatment regimens, and a lack of data on adverse effects. Further better designed studies are needed to support antibiotic prophylaxis and, should these prove beneficial, to compare beta-lactams with quinolones directly.

Expression of multidrug resistance proteins in rat and human chronic pancreatitis

BACKGROUND AND AIMS

The expression of the ABC-transporters MDR-1, MRP1, and MRP-2 was investigated in healthy pancreas and in chronic pancreatitis tissue samples in rats and humans to evaluate their possible involvement in a multidrug resistance of the pancreas with consequences for the pharmacologic treatment of pancreatic diseases.

METHODS

Human pancreatic tissue samples of healthy tissue and chronic pancreatitis were collected during pancreas surgery. In rats, the time-course of the expression of transporter proteins was studied 14, 28, and 56 days after experimental induction of chronic pancreatitis. The expression of MDR-1, MRP-1, MRP-2, and furthermore, LRP and PAP was investigated by RT-PCR, Real Time TaqManPCR, and immunohistochemistry.

RESULTS

In rat pancreas, MDR-1 (P-gp) and MRP-1 but in human pancreas MDR-1 (P-gp), MRP-1 and MRP-2 were found to be expressed. Chronic pancreatitis lead to an increased transcription of mRNA of MDR-1 (rat and human) and much lower, MRP-2 (human).

CONCLUSIONS

The expression of P-gp and related transporters could have impact on the metabolism, distribution, and availability of various compounds, including drugs, in the pancreas. The results indicate that this could be more pronounced in chronic pancreatitis.

Deferoxamine and meropenem combination therapy in experimental acute pancreatitis

INTRODUCTION

Recent data from the experimental clinical studies suggest that antibiotics having good penetration to pancreas may reduce mortality by preventing pancreatic infection, which is the most important prognostic factor in acute pancreatitis (AP). Deferoxamine is an active free oxygen radical scavenger, which has been shown to have a protective role in development of acute pancreatitis.

AIM

To determine the effects of combination of deferoxamine and meropenem in acute necrotizing pancreatitis.

METHODOLOGY

One hundred male Sprague-Dawley rats were randomly divided into 5 groups. All rats underwent laparotomy with cannulation of biliopancreatic duct. Group 1 received intraductal saline injection. Acute necrotizing pancreatitis was induced in group 2, 3, 4, and 5 by intraductal injection of 3% taurocholate. Group 1 (sham operated) and group 2 were injected with saline of 0.3 mL/kg intraperitoneally (i.p). Group 3 was injected with meropenem 60 mg/kg/d i.p, group 4 with deferoxamine 80 mg/kg/d s.c and group 5 with combination of these 2 agents at the same doses. While meropenem was started 2 hours later, all treatments were started immediately after the induction of pancreatitis. All rats were killed at the 48th hour of the treatment and blood and tissue samples were collected for amylase determinations, pathologic examinations, and culture.

RESULTS

There was no difference in serum amylase levels between AP induced groups (P > 0.05). Pancreatic histology scores were significantly low in rats treated with deferoxamine (group 4), and combination regimen (group 5) (P < 0.001). Meropenem significantly reduced the incidence of pancreatic infection. Although combination of deferoxamine with meropenem showed better effects than meropenem alone in terms of pancreatic infection, the difference did not reach to statistical significance.

CONCLUSIONS

Meropenem treatment reduces secondary pancreatic infections in acute pancreatitis. Treatment with deferoxamine and meropenem combination may be more beneficial than single therapies in reducing the severity of pancreatitis. Further studies investigating the effects of this combination on survival are needed.

Cefepime tissue penetration in experimental acute pancreatitis

INTRODUCTION

Antibiotic treatment represents a cornerstone in the management of severe acute pancreatitis. However, different antibiotic substances are currently used. In this study, we analyzed penetration of cefepime into pancreatic tissue in two models of acute pancreatitis.

AIMS AND METHODOLOGY

Following induction of acute pancreatitis, animals were treated with a single intravenous dose of cefepime (0.1 mg/g of body weight). At two different time points, blood and tissue samples were obtained for determination of cefepime concentration and microbiologic analysis.

RESULTS

Mean pancreatic tissue concentrations +/- SEM 30 minutes after drug administration were significantly higher in animals with either mild acute pancreatitis (113 +/- 22 mg/kg) or severe acute pancreatitis (75 +/- 22 mg/kg) than in control animals (30 +/- 6 mg/kg) (p < 0.005). The minimal inhibitory concentrations (MIC90) for organisms usually isolated from infected pancreatic necrosis vary between 0.05 and 8 mg/L, which is between nine and 1,500 times lower than the mean peak concentration found in necrotic pancreatic tissue. Seven hours 30 minutes after antibiotic administration, pancreatic cefepime concentrations were still above the MIC90 in 100% and 83% of animals with mild and severe disease, respectively. The infection rate of pancreatic tissue was significantly lower after antibiotic treatment and was similar after imipenem/cilastatin or cefepime treatment.

CONCLUSION

Because of its antibacterial coverage and proven tissue penetration in acute pancreatitis, cefepime should be studied in patients with severe acute pancreatitis.

Antibiotic therapy for prophylaxis against infection of pancreatic necrosis in acute pancreatitis

BACKGROUND

Acute pancreatitis is a common acute abdominal emergency which lacks specific therapy. In severe attacks, areas of the pancreas may become necrotic. The mortality risk rises to >40% if sterile necrosis becomes superinfected, usually with gut derived aerobic organisms. Experimental and clinical studies indicate a window of opportunity of 1-2 weeks, when superinfection, and thus high-risk surgical debridement, may be prevented by administering systemic antibiotics to 'sterilise' tissues adjacent to necrotic areas. There are theoretical risks of encouraging antibacterial resistance and opportunistic fungal infections.

OBJECTIVES

To determine the effectiveness and safety of prophylactic antibiotic therapy in patients with severe acute pancreatitis who have developed pancreatic necrosis.

SEARCH STRATEGY

MEDLINE, EMBASE, and the Cochrane Library were searched. We also examined other sources including Conference Abstracts (published and unpublished data).

SELECTION CRITERIA

Randomised controlled trials (RCT) were sought using the search strategy detailed below. No linguistic limitations were applied. RCTs were selected in which antibacterial therapy was evaluated in patients with severe acute pancreatitis associated with pancreatic necrosis proven by intravenous contrast-enhanced computed tomography (CT). No linguistic limitations were applied. Searching was undertaken initially in November 2001 and updated in March 2003.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data from trial publications independently, concerning rates for the primary end-points: with respect to: all cause mortality and rates of infection of pancreatic necrosis (proven by microbiological examination of fine needle aspirate or operative specimens). In addition, secondary end-points included peri-pancreatic sepsis, remote sepsis (respiratory, urinary, central venous line sources), operative rates, length of hospital stay, adverse events including the incidence of drug resistant microorganisms and opportunistic fungal infection.

MAIN RESULTS

It was possible to evaluate mortality in all four included studies, and it demonstrated a survival advantage for antibiotic therapy (Odds ratio 0.32, p=0.02). Pancreatic sepsis (infected necrosis) was also measurable in all four studies and showed an advantage for therapy (Odds ratio 0.51, p=0.04). Extra-pancreatic infection could be evaluated in three studies, but showed no significant advantage for therapy (Odds ratio 0.47, p=0.05).Operative treatment data was available in three studies, but surgery rates were not significantly reduced (Odds ratio 0.55, p=0.08). Fungal infections showed no strongly increased preponderance with therapy (Odds ratio 0.83, p=0.7), but there were no data on infection with resistant organisms. Length of hospital stay could only be evaluated in two studies and was not significantly different. Sub-group analyses planned for the influence on outcome measures of the antibiotic regimen, the time of commencement of therapy in relation to symptom onset and/or hospitalisation, duration of therapy, and aetiology could not be performed as no data were available.

REVIEWER'S CONCLUSIONS

Despite variations in drug agent, case mix, duration of treatment and methodological quality (especially the lack of double blinded studies), there was strong evidence that intravenous antibiotic prophylactic therapy for 10 to 14 days decreased the risk of superinfection of necrotic tissue and mortality in patients with severe acute pancreatitis with proven pancreatic necrosis at CT. Further studies are required to confirm all of the benefits suggested (in particular the need for operative debridement), to provide more adequate data on adverse effects, to address the choice of antibacterial agents and effects of varying duration of therapy, and whether outcome is related to aetiology.

Nonsurgical management of acute pancreatitis. Use of antibiotics

In severe AP, infected necrosis is the leading cause of death. Prevention of pancreatic infection is the major goal in the treatment of patients with necrotizing pancreatitis. Adequate early antibiotic therapy seems to be promising in these patients. Their role and the optimal timing of the antibiotic therapy (e.g., benefit of prophylactic application) are discussed. Preliminary results of a study in patients with infected pancreatic necrosis and exclusively or primarily conservative treatment also are presented.

A critical review of antibiotic prophylaxis in severe acute pancreatitis

The close association between infection and poor outcome in severe pancreatitis has led many investigators to hypothesize that antibiotic prophylaxis might reduce infection and thereby reduce mortality. However, despite this possible relationship, few studies of good quality have been performed in humans. Comprehensive searches using Medline and reviewing relevant published bibliographies of English-language human and experimental literature concerning acute pancreatitis or pancreatic tissue and antibiotic therapy or pharmacokinetics were conducted. Ample experimental evidence indicates that aminoglycosides penetrate pancreatic tissue poorly and that penetration of penicillins is variable, although the relevance of this is debatable, because most tissue that requires debridement in severe pancreatitis is necrotic peripancreatic retroperitoneal fat, not the pancreas itself. Although several animal studies suggest that antibiotic prophylaxis would be beneficial in severe pancreatitis, two recent randomized studies of intravenous antibiotics in humans provide conflicting data. There are insufficient data to recommend the use of selective digestive decontamination. Some justification exists for the use of intravenous antibiotic prophylaxis in severe pancreatitis, but the data are insufficient to mandate prophylaxis or to elevate it to the standard of care. If chosen, prophylaxis with the combination of a fluoroquinolone plus metronidazole, or monotherapy with a carbapenem antibiotic, would be most appropriate. Several other questions-including the minimum degree of severity that will benefit, the validity of endpoints other than mortality, and reduction of the need for surgical drainage-require additional trials.

Penetration of ciprofloxacin into the human pancreas

The aim of this study was to determine the concentrations of ciprofloxacin in human pancreatic tissue and juice. Concentrations were measured by high-pressure liquid chromatography (HPLC). Two hundred mg of ciprofloxacin were administered as a short i.v. infusion (30 min). The median ciprofloxacin concentrations 140 min (median) after the start of infusion in pancreatic tissue as well as in pancreatic juice were 0.9 mg/kg (mg/l). The penetration ratio was 1.0 for pancreatic tissue and 0.83 for pancreatic juice. With regard to the minimal inhibitory concentrations (MIC) for the respective bacteria, ciprofloxacin seems to be an appropriate drug for the treatment of septic complications in necrotizing pancreatitis. Future clinical trials are necessary to prove this assumption.

Behavior of antibiotics during human necrotizing pancreatitis

The aim of the study was to verify whether antibiotics excreted by the normal pancreas are also excreted in human necrotizing pancreatitis, reaching the tissue sites of the infection. Twelve patients suffering from acute necrotizing pancreatitis were treated with imipenem-cilastatin (0.5 g), mezlocillin (2 g), gentamicin (0.08 g), amikacin (0.5 g), pefloxacin (0.4 g), and metronidazole (0.5 g). Serum and necrotic samples were collected simultaneously at different time intervals after parenteral drug administration by computed tomography-guided needle aspiration, intraoperatively, and from surgical drainages placed during surgery. Drug concentrations were determined by microbiological and high-performance liquid chromatography assays. All antibiotics reached the necrotic tissues, but with varying degrees of penetration, this being low for aminoglycosides (13%) and high in the case of pefloxacin (89%) and metronidazole (99%). The concentrations of pefloxacin (13.0 to 23 micrograms/g) and metronidazole (8.4 micrograms/g) in the necrotic samples were distinctly higher than the MICs for the organisms most commonly isolated in this disease; the concentrations in tissue of imipenem (3.35 micrograms/g) and mezlocillin (8.0 and 15.0 micrograms/g) did not always exceed the MICs for 90% of strains tested, whereas the aminoglycoside concentrations in necrotic tissue (0.5 microgram/g) were inadequate. Repeated administration of drugs (for 3, 7, 17, and 20 days) seems to enhance penetration of pefloxacin, imipenem, and metronidazole into necrotic pancreatic tissue. The choice of antibiotics in preventing infected necrosis during necrotizing pancreatitis should be based on their antimicrobial activity, penetration rate, persistence, and therapeutic concentrations in the necrotic pancreatic area. These requisites are provided by pefloxacin and metronidazole and to a variable extent by imipenem and mezlocillin.

Comparison of 5-fluorouracil anabolite levels after intravenous bolus and continuous infusion

The levels of 5-fluorouracil (5FU) and its anabolites in the serum, bile, pancreatic juice, liver, pancreas, and skeletal muscle of dogs were compared after single bolus administration and after continuous infusion. Six dogs had a bolus of 5FU (15 mg/kg) and were studied for 120 min. Five dogs had a continuous infusion of 5FU (30 mg/kg) and were studied for 24 h. After the bolus infusion, serum 5FU levels were initially high and then declined, whereas anabolite levels gradually increased over 45 min. Within 2 h, anabolite levels exceeded 5FU levels in tissues but were undetectable in bile and pancreatic juice. During the continuous infusion, anabolite levels in serum increased more rapidly than 5FU levels and remained significantly higher for 24 h. Anabolite levels also exceeded 5FU levels in bile, pancreatic juice, pancreas, and muscle but not in the liver. Continuous infusion of 5FU produced higher levels of the anabolites than did bolus infusion and maintained constant levels throughout the infusion period.

Penetration of ceftazidime into human pancreas

The use of antibiotics in patients with severe acute pancreatitis (stage II and III) is indicated since bacterial complications are the most common cause of death in these patients. In the present study the penetration of ceftazidime into pancreatic juice, into healthy and chronically inflamed pancreatic tissue as well as into necrotic regions in cases of severe acute pancreatitis was investigated. A peak concentration of 12.9 +/- 5.9 mg/l was found 60 min after intravenous administration of 35 mg/kg of the drug, which is 32% of the corresponding serum levels. Pancreatic tissue concentrations varied between 9 and 79% of the corresponding serum levels, depending on the stage of inflammation. After five days of antibiotic treatment with doses of 2 g t.i.d., concentrations between 1.8 and 6.9 mg/kg were detected even in pancreatic necroses. This suggests that sufficient antibacterial levels of ceftazidime were present in all pancreatic compartments analyzed following administration of common therapeutic dosages. Therefore, from a pharmacokinetic point of view, ceftazidime could be a potentially effective drug for the treatment of pancreatitis.

Pancreatic infection complicating acute pancreatitis

Pancreatic infection is the leading cause of death from acute pancreatitis. Patients with severe necrotizing pancreatitis are most at risk. Early computed tomography and percutaneous fine-needle aspiration microbiology of areas of pancreatic necrosis enable early diagnosis. Pancreatic infection should be treated surgically, although sterile necrosis may be managed conservatively. The role of antimicrobial drugs is uncertain.

Hepatopancreatic uptake and elimination of 5-fluorouracil after intravenous injection

The efficacy of 5-fluorouracil (5FU) chemotherapy depends, in part, upon maintaining adequate intracellular levels of active metabolites. The uptake, distribution and elimination of 5FU and 5FU-anabolites were determined after an intravenous bolus infusion of 5FU, 15 mg kg-1, and the relationship between serum and tissue levels were evaluated. In six dogs samples of liver, pancreas, rectus abdominus muscle, blood, bile and pancreatic juice were collected at 0, 15, 45, 90 and 120 min. Bile and pancreatic juice levels of 5FU followed the same pattern as the serum, rising rapidly and falling exponentially, suggesting elimination by simple diffusion. Elimination of anabolites was more complex. Tissue levels of anabolites were highest in the liver and peaked later than in the pancreas and muscle. They were unrelated to serum levels of 5FU. The higher and more sustained levels of 5FU-anabolites in the liver may be responsible for some of the beneficial effects of 5FU chemotherapy on hepatic tumours.

Human pancreatic tissue concentration of bactericidal antibiotics

Pancreatic infection represents the most important cause of fatal outcome in human acute pancreatitis. In a comparative analysis, human pancreatic tissue concentrations of 10 different bactericidal antibiotics were determined in 89 patients undergoing pancreatic surgery. Concentrations of the antibiotics were determined in the blood and pancreatic tissue using high-pressure liquid chromatography. Pancreatic tissue concentrations 120 minutes after intravenous administration were as follows: mezlocillin, 19.0 mg/kg; piperacillin, 20.3 mg/kg; cefotaxime, 9.1 mg/kg; ceftizoxime, 7.9 mg/kg; netilmicin, 0.4 mg/kg; tobramycin, 0.4 mg/kg; ofloxacin, 1.7 mg/kg; ciprofloxacin, 0.9 mg/kg; imipenem, 6.0 mg/kg; metronidazole, 3.5 mg/kg. Three groups of antibiotics were established: group A, substances with low tissue concentrations (netilmicin, tobramycin), which were below the minimal inhibitory concentrations of most bacteria found in pancreatic infection; group B, antibiotics with pancreatic tissue concentrations which were sufficient to inhibit some but not all bacteria in pancreatic infection (mezlocillin, piperacillin, ceftizoxime, cefotaxime); group C, substances with high pancreatic tissue levels as well as high bactericidal activity against most of the germs present in pancreatic infection (ciprofloxacin, ofloxacin, imipenem). These data could serve as the basis for adequate antibiotic prophylaxis or treatment of pancreatic infection.

Antibacterial and mezlocillin-enhancing activity of pure human pancreatic fluid

The majority of deaths in severe pancreatitis are the result of superinfection of necrotic tissue. The pathogen most commonly responsible for such infections is Escherichia coli. Antibiotic prophylaxis would appear a logical precaution. The antibacterial drugs of choice should possess two basic characteristics: they must be active against the flora responsible for the infections and must be capable of penetrating into the pancreas at adequate minimum inhibitory concentrations (MICs). Mezlocillin--which is active against E. coli--has been shown to possess the latter requisite, but achieving therapeutic concentrations requires administration at high doses. In the present study, pure human pancreatic fluid showed properties similar to those observed in the dog against E. coli (bacterial colony growth 100 times lower than in a control culture) and produced a 75% reduction in mezlocillin MICs against this organism. These enhancing characteristics might make the commonly used doses sufficient for prophylactic purposes.

Antibiotics in acute pancreatitis. Current status and future directions

Infectious complications currently account for 80 percent of deaths from acute pancreatitis. The adjunctive role of antibiotics in the prevention and treatment of secondary pancreatic infections has received insufficient attention. Randomized clinical studies of effective antibiotics for prophylaxis or empiric therapy of pancreatic infections do not currently exist. In their absence, it is not known whether prophylactic antibiotics are useful in patients with acute pancreatitis. Until such studies are available, if antibiotics are to be used, their choice must be based upon indirect criteria: the ability of the antibiotic to effectively penetrate pancreatic tissue and juice, knowledge of the most common pancreatic pathogens, and the ability of the antibiotic to exceed the in vitro concentration (MIC-90) in pancreatic juice for the common pathogens. Recognition of the limited state of knowledge regarding antibiotics in acute pancreatitis may stimulate future investigations.

Biliary and pancreatic excretion of cefamandole

After intravenous infusion of secretin and cholecystokinin in six dogs, cefamandole (50 mg/kg of body weight) was given intravenously for 10 min. Samples of serum, bile, pancreatic juice, liver, pancreas, fat, and muscle were collected over a 2-h period. Cefamandole levels were measured by a microbiological assay. The highest levels were as follows: serum, 160 micrograms/ml; bile, 3,071 micrograms/ml; pancreatic juice, 7 micrograms/ml; liver, 101 micrograms/g; pancreas, 44 micrograms/g; muscle, 20 micrograms/g; and fat, 14 micrograms/g. Levels in pancreatic juice were extremely low compared with levels in pancreatic tissue, suggesting the existence of a barrier to excretion at the ductal membrane.

The penetration of antibiotics into human pancreas

In order to analyse the penetration of two antibiotics (mezlocillin and metronidazole) which cover the spectrum of microorganisms involved in pancreatic infection, we determined their concentration in pancreatic tissue, juice and cyst fluid in 16 patients undergoing pancreatic surgery. In addition, the external pancreatic fistula fluid of one patient was analysed for antibiotic concentration and bacterial counts during a seven-day treatment with mezlocillin, metronidazole and netilmicin (i.v.). Antibiotic concentrations were determined by HPLC between 16 and 210 (median 74) min after i.v. administration of 4 g mezlocillin and 500 mg metronidazole, respectively. The median concentration of mezlocillin was 23.2 (range: 3.1-37.4) mg/kg, 15.9 (range: 4.2-55.0) mg/l and 9.9 (range: 5.2-14.8) mg/l in pancreatic tissue, juice and cyst fluid, respectively. The median concentration of metronidazole was 5.1 (range: 1.8-13.0) mg/kg, 8.5 (range: 3.6-16.2) mg/l and 1.2 (0.9-1.4) mg/l in pancreatic tissue, juice and cyst fluid, respectively. From the fistula patient, seven different bacteria were cultured (five aerobic and two anaerobic isolates); their concentration in fistula fluid ranged from 10(5) to 10(7) CFU/ml. The bacteria sensitive for mezlocillin and metronidazole disappeared after four days of i.v. treatment, whereas the two isolates sensitive for netilmicin showed continuous growth seven days after i.v. treatment. The peak concentrations for mezlocillin, metronidazole and netilmicin in the fistula fluid were 6.8 mg/l, 5.6 mg/l and less than 0.1 mg/l, respectively.