Bactericidal/permeability-increasing protein preserves leukocyte functions after major liver resection

rBPI21 (Opebacan) Promotes Rapid Trilineage Hematopoietic Recovery in a Murine Model of High-Dose Total Body Irradiation

The complexity of providing adequate care after radiation exposure has drawn increasing attention. While most therapeutic development has focused on improving survival at lethal radiation doses, acute hematopoietic syndrome (AHS) occurs at substantially lower exposures. Thus, it is likely that a large proportion of such a radiation-exposed population will manifest AHS of variable degree and that the medical and socioeconomic costs of AHS will accrue. Here, we examined the potential of rBPI21 (opebacan), used without supportive care, to accelerate hematopoietic recovery after radiation where expected survival was substantial (42-75%) at 30 days). rBPI21 administration was associated with accelerated recovery of hematopoietic precursors and normal marrow cellularity, with increases in megakaryocyte numbers particularly marked. This translated into attaining normal trilineage peripheral blood counts 2-3 weeks earlier than controls. Elevations of hematopoietic growth factors observed in plasma and the marrow microenvironment suggest the mechanism is likely multifactorial and not confined to known endotoxin-neutralizing and cytokine down-modulating activities of rBPI21 . These observations deserve further exploration in radiation models and other settings where inadequate hematopoiesis is a prominent feature. These experiments also model the potential of therapeutics to limit the allocation of scarce resources after catastrophic exposures as an endpoint independent of lethality mitigation. This article is protected by copyright. All rights reserved.

Interest of preoperative immunonutrition in liver resection for cancer: study protocol of the PROPILS trial, a multicenter randomized controlled phase IV trial

BACKGROUND

Malnutrition is an independent risk factor of postoperative morbidity and mortality and it's observed in 20 to 50% of surgical patients. Preoperative interventions to optimize the nutritional status, reduce postoperative complications and enteral nutrition has proven to be superior to the parenteral one. Moreover, regardless of the nutritional status of the patient, surgery impairs the immunological response, thus increasing the risk of postoperative sepsis. Immunonutrition has been developed to improve the immunometabolic host response in perioperative period and it has been proven to reduce significantly postoperative infectious complications and length of hospital stay in patients undergoing elective gastrointestinal surgery for tumors. We hypothesize that a preoperative oral immunonutrition (ORAL IMPACT®) can reduce postoperative morbidity in liver resection for cancer.

METHODS/DESIGN

Prospective multicenter randomized placebo-controlled double-blind phase IV trial with two parallel treatment groups receiving either study product (ORAL IMPACT®) or control supplement (isocaloric isonitrogenous supplement--IMPACT CONTROL®) for 7 days before liver resection for cancer. A total of 400 patients will be enrolled. Patients will be stratified according to the type of hepatectomy, the presence of chronic liver disease and the investigator center. The main end-point is to evaluate in intention-to-treat analysis the overall 30-day morbidity. Secondary end-points are to assess the 30-day infectious and non-infectious morbidity, length of antibiotic treatment and hospital stay, modifications on total food intake, compliance to treatment, side-effects of immunonutrition, impact on liver regeneration and sarcopenia, and to perform a medico-economic analysis.

DISCUSSION

The overall morbidity rate after liver resection is 22% to 42%. Infectious post-operative complications (12% to 23%) increase the length of hospital stay and costs and are responsible for a quarter of 30-day mortality. Various methods have been advocated to decrease the rate of postoperative complications but there is no evidence to support or refute the use of any treatment and further trials are required. The effects of preoperative oral immunonutrition in non-cirrhotic patients undergoing liver resection for cancer are unknown. The present trial is designed to evaluate whether the administration of a short-term preoperative oral immunonutrition can reduce postoperative morbidity in non-cirrhotic patients undergoing liver resection for cancer.

TRIAL REGISTRATION

Clinicaltrial.gov: NCT02041871.

Uncontrolled sepsis: a systematic review of translational immunology studies in intensive care medicine

BACKGROUND

The design of clinical immunology studies in sepsis presents several fundamental challenges to improving the translational understanding of pathologic mechanisms. We undertook a systematic review of bed-to-benchside studies to test the hypothesis that variable clinical design methodologies used to investigate immunologic function in sepsis contribute to apparently conflicting laboratory data, and identify potential alternatives that overcome various obstacles to improve experimental design.

METHODS

We performed a systematic review of the design methodology employed to study neutrophil function (respiratory burst), monocyte endotoxin tolerance and lymphocyte apoptosis in the intensive care setting, over the past 15 years. We specifically focussed on how control samples were defined, taking into account age, gender, ethnicity, concomitant therapies, timing of sample collection and the criteria used to diagnose sepsis.

RESULTS

We identified 57 eligible studies, the majority of which (74%) used case-control methodology. Healthy volunteers represented the control population selected in 83% of studies. Comprehensive demographic data on age, gender and ethnicity were provided in ≤48% of case control studies. Documentation of diseases associated with immunosuppression, malignancy and immunomodulatory therapies was rare. Less than half (44%) of studies undertook independent adjudication for the diagnosis of sepsis while 68% provided microbiological data. The timing of sample collection was defined by highly variable clinical criteria. By contrast, surgical studies avoided many such confounders, although only one study in surgical patients monitored the study group for development of sepsis.

CONCLUSIONS

We found several important and common limitations in the clinical design of translational immunologic studies in human sepsis. Major elective surgery overcame many of these methodological limitations. The failure of adequate clinical design in mechanistic studies may contribute to the lack of translational therapeutic progress in intensive care medicine.

Bactericidal/permeability-increasing protein in host defense and its efficacy in the treatment of bacterial sepsis

The 55-kD bactericidal/permeability-increasing protein (BPI) is a neutrophil-derived polypeptide belonging to a family of lipid and endotoxin binding proteins. BPI is composed of two functionally distinct structural domains: a potently antibacterial and antiendotoxin ∼ 20-kD aminoterminal half, and an opsonic carboxy-terminal portion. In multiple animal models, a recombinant amino-terminal fragment of BPI (rBPI21) is nontoxic and protects against gram-negative bacteria and endotoxin. In humans, rBPI21 is also nontoxic and nonimmunogenic and has undergone phase II/III clinical trials with apparent therapeutic benefit.

Bactericidal/permeability-increasing protein (rBPI21) and fluoroquinolone mitigate radiation-induced bone marrow aplasia and death

Identification of safe, effective treatments to mitigate toxicity after extensive radiation exposure has proven challenging. Only a limited number of candidate approaches have emerged, and the U.S. Food and Drug Administration has yet to approve any agent for a mass-casualty radiation disaster. Because patients undergoing hematopoietic stem cell transplantation undergo radiation treatment that produces toxicities similar to radiation-disaster exposure, we studied patients early after such treatment to identify new approaches to this problem. Patients rapidly developed endotoxemia and reduced plasma bactericidal/permeability-increasing protein (BPI), a potent endotoxin-neutralizing protein, in association with neutropenia. We hypothesized that a treatment supplying similar endotoxin-neutralizing activity might replace the BPI deficit and mitigate radiation toxicity and tested this idea in mice. A single 7-Gy radiation dose, which killed 95% of the mice by 30 days, was followed 24 hours later by twice-daily, subcutaneous injections of the recombinant BPI fragment rBPI21 or vehicle alone for 14 or 30 days, with or without an oral fluoroquinolone antibiotic with broad-spectrum antibacterial activity, including that against endotoxin-bearing Gram-negative bacteria. Compared to either fluoroquinolone alone or vehicle plus fluoroquinolone, the combined rBPI21 plus fluoroquinolone treatment improved survival, accelerated hematopoietic recovery, and promoted expansion of stem and progenitor cells. The observed efficacy of rBPI21 plus fluoroquinolone initiated 24 hours after lethal irradiation, combined with their established favorable bioactivity and safety profiles in critically ill humans, suggests the potential clinical use of this radiation mitigation strategy and supports its further evaluation.

Methods of decreasing infection to improve outcomes after liver resections

BACKGROUND

Infections cause both morbidity and mortality in patients undergoing liver resection. Various methods have been advocated to decrease the infectious complications after liver resection. We do not know if they are of any benefit to the patient or the health-care funder.

OBJECTIVES

To determine the benefits and harms of different interventions in decreasing the infectious complications and improving the outcomes after liver resection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until August 2011.

SELECTION CRITERIA

We included all randomised clinical trials that were performed to compare interventions aimed at decreasing the infectious complications after liver resection.

DATA COLLECTION AND ANALYSIS

Two authors independently identified the trials and extracted the data. We analysed the data with both the fixed-effect and the random-effects model using RevMan Analysis. For each outcome we calculated the risk ratio (RR), rate ratio, or mean difference (MD) with 95% confidence intervals (CI) based on available patient data analysis.

MAIN RESULTS

We included seven trials including 521 patients for this review. The sample size in the trials varied from 12 to 180 patients. All the trials were of high risks of systematic errors and of random errors. Four trials included patients who underwent liver resection only. In the remaining three trials, patients underwent combined liver resection with extrahepatic biliary resection resulting in a biliary enteric anastomosis. Four trials included only major liver resection. The remaining three trials included a mixture of major and minor liver resections. It appears that the proportion of cirrhotic patients in the trials was very low. The comparisons performed included whether antibiotics are necessary routinely during the peri-operative period of liver resection, the duration of antibiotics, the use of prebiotics and probiotics in the perioperative period, use of recombinant bactericidal-permeability increasing protein 21 (rBPI21), and the use of topical povidone iodine gel at the time of wound closure. Only one or two trials were included under each comparison. There was no significant differences in mortality or severe morbidity in any of the comparisons. Quality of life was not reported in any of the trials.

AUTHORS' CONCLUSIONS

There is currently no evidence to support or refute the use of any treatment to reduce infectious complications after liver resections. Further well designed trials with low risk of systematic error and low risk of random errors are necessary.

Neutrophil phenotype and function in partial hepatectomy in man

PURPOSE

Hepatic resections are still associated with considerable morbidity mainly because of postoperative infection. Adequate function of neutrophils is a crucial element in host defense. The aim of the study was to characterize neutrophils during partial hepatectomy.

METHODS

Fourteen patients undergoing partial liver resection were enrolled. Twenty-four hours pre-, intra- (after induction of anesthesia, after preparation of the liver, and 15 min after release of the Pringle maneuver), as well as postoperatively (3 h after Pringle; 24, 48, and 120 h after surgery), blood samples were obtained. In addition, healthy volunteers (n = 5) were investigated. Adhesion molecules (CD 62, CD 18), Fcy receptors (CD 16, CD 32), and phagocytosis by neutrophils were characterized by fluorescence-activated cell sorter analysis. Spontaneous and stimulated (formyl-methionyl-leucyl-phenylalanine) oxygen radical generation was measured by lucigenin-enhanced chemiluminescence.

RESULTS

Numeric upregulation of CD 62 and CD 18 on neutrophils was seen before the use of Pringle maneuver and persisted thereafter (p < 0.05). Spontaneous numeric expression of Fcy receptors (CD16 and CD 32) was unchanged during liver dissection but downregulated after Pringle maneuver was opened (p < 0.05). Although numeric Fcy receptors were downregulated, phagocytosis of heterologous opsonized Escherichia coli bacteria by neutrophils was unaffected. Spontaneous oxygen radical production peaked sharply 15 min after release of the Pringle maneuver (p < 0.05), contrary to stimulated oxygen radical production, which was depressed 3 h after the release of the Pringle maneuver (ns).

CONCLUSIONS

Uneventful partial hepatectomy in man resulted already in a significant change in the phenotype but in less significant changes in the functions of neutrophils.

Increased bactericidal/permeability increasing protein in patients with cirrhosis

BACKGROUND

High levels of endotoxin in patients with cirrhosis are thought to be responsible for the activation of tumour necrosis factor-alpha (TNF)-alpha-mediated pro-inflammatory pathways involved in haemodynamic alterations. Bactericidal/permeability increasing protein (BPI) is a protein found in neutrophils with endotoxin-binding and neutralization capacity. It is not known whether defective BPI production or release is present in cirrhosis.

AIMS

We investigated the levels of BPI in cirrhotic patients and its relation to other endotoxin-binding proteins and inflammatory markers.

METHODS

Plasmatic levels of BPI, lipopolysaccharide-binding protein, soluble CD14, TNF-alpha and BPI mRNA expression in neutrophils were determined in 130 patients and 30 healthy controls. The capacity of patients' plasma to inhibit lipopolysaccharide (LPS)-mediated TNF-alpha production by monocytes from healthy donors was assessed in vitro.

RESULTS

Patients with cirrhosis exhibited an increase in BPI mRNA and plasma level of BPI when compared with healthy controls (P<0.05). Child C group displayed the highest frequency of patients with a high concentration of BPI. A positive correlation was found between TNF-alpha and plasma levels of BPI (P<0.01). High levels of BPI in plasma were able to significantly reduce in vitro TNF-alpha release by monocytes after a challenge with LPS (8.54 +/- 1.04 vs. 10.44 +/- 0.85 pg/ml, P=0.028).

CONCLUSION

BPI is increased in cirrhotic patients, especially in those with more severe liver disease. The amount of BPI in the plasma correlated with the TNF-alpha level and was able to reduce LPS-mediated TNF production by monocytes. BPI possibly plays a regulatory role by antagonizing the pro-inflammatory mechanisms mediated by TNF-alpha.

Antioxidant enriched enteral nutrition and oxidative stress after major gastrointestinal tract surgery

AIM: To investigate the effects of an enteral supple-ment containing antioxidants on circulating levels of antioxidants and indicators of oxidative stress after major gastrointestinal surgery.

METHODS: Twenty-one patients undergoing major upper gastrointestinal tract surgery were randomised in a single centre, open label study on the effect of postoperative enteral nutrition supplemented with antioxidants. The effect on circulating levels of antioxidants and indicators of oxidative stress, such as F2-isoprostane, was studied.

RESULTS: The antioxidant enteral supplement showed no adverse effects and was well tolerated. After surgery a decrease in the circulating levels of antioxidant parameters was observed. Only selenium and glutamine levels were restored to pre-operative values one week after surgery. F2-isoprostane increased in the first three postoperative days only in the antioxidant supplemented group. Lipopolysaccharide binding protein (LBP) levels decreased faster in the antioxidant group after surgery.

CONCLUSION: Despite lower antioxidant levels there was no increase in the circulating markers of oxidative stress on the first day after major abdominal surgery. The rise in F2-isoprostane in patients receiving the antioxidant supplement may be related to the conversion of antioxidants to oxidants which raises questions on antioxidant supplementation. Module AOX restored the postoperative decrease in selenium levels. The rapid decrease in LBP levels in the antioxidant group suggests a possible protective effect on gut wall integrity. Further studies are needed on the role of oxidative stress on outcome and the use of antioxidants in patients undergoing major abdominal surgery.

Lipopolysaccharide-binding protein plasma levels and liver TNF-alpha gene expression in obese patients: evidence for the potential role of endotoxin in the pathogenesis of non-alcoholic steatohepatitis

BACKGROUND

Some lines of evidence suggest that endotoxin may induce non-alcoholic steatohepatitis (NASH) in a background of fatty liver. However, a clear association between increased endotoxemia and development of steatohepatitis in obese patients has not been confirmed. We aim to assess the endotoxemic state of patients with non-alcoholic fatty liver disease (NAFLD) and its relationship with the liver expression of TNF-alpha and the presence of NASH.

METHODS

Prospective study comprising 40 patients with morbid obesity who were diagnosed with NAFLD. Blood samples and liver biopsies were collected. Endotoxemia was assessed by the evaluation of circulating level of LPS-binding protein (LBP). Plasma levels of LBP and TNF-alpha were assessed by ELISA. The expression of TNF-alpha in liver tissue was evaluated by real-time PCR. Histological examination was performed to evaluate the presence of steatosis or NASH.

RESULTS

Levels of LBP were increased in obese patients with NAFLD. In addition, plasma level of LBP was increased in patients with steatohepatitis (14.2 +/- 3.9 microg/mL) when compared with patients with simple steatosis (11.5 +/- 3.2 microg/mL), P=0.041. The TNF-alpha mRNA expression in liver tissue was significantly higher in patients with NASH. This increment correlated with the rise in plasma levels of LBP (r=0.412, P=0.036).

CONCLUSION

NAFLD patients have elevated plasma levels of LBP and they are further increased in patients with NASH. This increase is related to a rise in TNF-alpha gene expression in the hepatic tissue which supports a role for endotoxemia in the development of steatohepatitis in obese patients.

Bactericidal/permeability increasing protein attenuates the myocardial inflammation/dysfunction that occurs with burn complicated by subsequent infection

Intubation and mechanical ventilation after burn contribute to pneumonia-related infection. Although postburn presence or absence of endotoxin has been described, inactivation of Toll-like receptor 4 signaling has been shown to improve postburn organ function, suggesting that LPS participates in burn-related susceptibility to infection. We hypothesized that bactericidal/permeability-increasing protein (rBPI) given postburn would attenuate myocardial inflammation/dysfunction associated with postburn septic challenge given 7 days postburn. Rats were given burn over 40% total body surface area, lactated Ringer 4 ml.kg(-1).% burn(-1); burns received either vehicle or rBPI, 1 mg.kg(-1).h(-1) for 48 h postburn. Postburn day 7, subgroups of burns and shams were given intratracheal Klebsiella pneumoniae, 4 x 10(6) CFU to produce burn complicated by sepsis; additional sham and burn subgroups received intratracheal vehicle to produce sham sepsis. Vehicle-treated groups: 1) sham burn + sham sepsis 2) sham burn + sepsis, 3) burn + sham sepsis, 4) burn + sepsis. rBPI-treated groups: 5) sham burn + sham sepsis, 6) sham burn + sepsis, 7) burn + sham sepsis, 8) burn + sepsis. Cardiomyocyte cytokine secretion and myocardial function were studied 24 h after septic challenge, postburn day 8. Pneumonia-related infection 8 days after vehicle-treated burn produced myocyte cytokine secretion (pg/ml), indicated by increased myocyte TNF-alpha, 549 +/- 46; IL-1beta, 50 +/- 8; IL-6, 286 +/- 3 levels compared with levels in sham myocytes (TNF-alpha, 88 +/- 11; IL-1beta, 7 +/- 1; IL-6, 74 +/- 10; P < 0.05). Contractile dysfunction was evident from lower left ventricular pressure +/-dP/dt values in this group compared with sham. rBPI attenuated myocyte cytokine responses to septic challenge and improved contractile function, suggesting that burn-related mobilization of microbial-like products contribute to postburn susceptibility to infection.

Nuclear Receptor-Dependent Bile Acid Signaling Is Required for Normal Liver Regeneration

Liver mass depends on one or more unidentified humoral signals that drive regeneration when liver functional capacity is diminished. Bile acids are important liver products, and their levels are tightly regulated. Here, we identify a role for nuclear receptor-dependent bile acid signaling in normal liver regeneration. Elevated bile acid levels accelerate regeneration, and decreased levels inhibit liver regrowth, as does the absence of the primary nuclear bile acid receptor FXR. We propose that FXR activation by increased bile acid flux is a signal of decreased functional capacity of the liver. FXR, and possibly other nuclear receptors, may promote homeostasis not only by regulating expression of appropriate metabolic target genes but also by driving homeotrophic liver growth.

Effects of major liver resection, with or without recombinant bactericidal/permeability-increasing protein (rBPI21), on the angiogenic profile of patients with metastatic colorectal carcinoma

BACKGROUND

Surgery induces a process of wound healing, which has immunological and angiogenic aspects. Bactericidal/permeability-increasing protein (BPI) is found in azurophilic granules of human neutrophils, which is bactericidal and neutralizes lipo-polysaccharide (LPS). This may reduce postoperative infectious complications. In addition, BPI has been shown to be an inhibitor of angiogenesis.

METHODS

A total of 18 patients with metastasized colorectal carcinoma to the liver were double blind randomized. The levels of the pro-angiogenic factors interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) and the angiogenesis inhibitor endostatin were investigated after liver surgery with perioperative administration of either rBPI(21) or placebo.

RESULTS

The highest IL-6 levels were found during the first 24 hr and reached peak levels already at 2 hr postoperatively in both groups. In both groups VEGF levels decreased sharply in the postoperative hours, returning to baseline levels in the days afterwards. In both groups, an immediate decrease in endostatin levels was observed which remained significantly low. RBPI(21) transiently influenced IL-6 and VEGF.

CONCLUSIONS

RBPI(21) only marginally affected IL-6 and VEGF levels. Surgery per se induced an immediate immune response (IL-6) and an immediate angiogenic response, reflected in an initial VEGF decrease and a longer lasting decrease of endostatin. These findings demonstrate the dynamics of tissue responses in the first phase of wound healing.

In vivo interaction of endotoxin and recombinant bactericidal/permeability-increasing protein (rBPI23): hemodynamic effects in a human endotoxemia model

The cardiovascular derangement that results from the administration of endotoxin in healthy subjects is qualitatively similar to what is observed in patients in septic shock. The biological response to endotoxin is attributed in part to cytokine release. In experimental endotoxemia, recombinant bactericidal/permeability increasing protein (rBPI(23)) has shown a protective effect by binding endotoxin with the subsequent inhibition of the endotoxin-induced cytokine release and of neutrophil activation. In a controlled, blinded crossover study the early cardiovascular effects of rBPI(23) were investigated in an experimental endotoxemia model in humans. The beat-to-beat changes in arterial pressure and cardiac output following infusion of endotoxin (40 EU/kg body weight) and rBPI(23) (1 mg/kg) or placebo (human serum albumin, 0.2 mg/kg) were studied for 2 hours in 8 healthy male adults. Endotoxin or rBPI(23) alone did not induce significant cardiovascular changes. Endotoxin following rBPI(23) infusion elicited a fall in total peripheral resistance with its nadir after 4 minutes to 40% (range 16-53; P <.001) of control level. Mean arterial pressure showed little change, and the fall in total peripheral resistance was associated with a reflex increase in heart rate and cardiac output (32%; range 43-106). Changes in cardiovascular variables in the subsequent 2 hours were not significant. In vitro activation of the contact system by, respectively, rBPI(23), LPS, and LPS-rBPI(23) complexes was assessed. Following incubation with rBPI(23), LPS, and LPS-rBPI(23) complexes, complex levels were generated at levels comparable to those observed in the buffer control. The rapid vasodilatation by endotoxin administered concomitantly with rBPI(23) is not mediated by complement or contact system activation. The early vasodilatation is compensated by an increase in cardiac output, which therefore does not result in arterial hypotension. The monitoring of continuous cardiac output allows for the detection of rapid effects on systemic flow and conductance that go unnoticed in a recording of arterial pressure.