Pentoxifylline reduces acute lung injury in chronic endotoxemia

Pentoxifylline for treatment of sepsis and necrotising enterocolitis in neonates

BACKGROUND

Mortality and morbidity due to neonatal sepsis and necrotising enterocolitis (NEC) remain high despite the use of potent antimicrobial agents. Agents that modulate inflammation may improve outcomes. Pentoxifylline (PTX), a phosphodiesterase inhibitor, is one such agent. This is an update of a review first published in 2003 and updated in 2011 and 2015.

OBJECTIVES

To assess the effectiveness and safety of intravenous PTX as an adjunct to antibiotic therapy on mortality and morbidity in neonates with suspected or confirmed sepsis and neonates with NEC.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and trial registries in July 2022. We also searched the reference lists of identified clinical trials and handsearched conference abstracts.   SELECTION CRITERIA: We included randomised controlled trials (RCTs) or quasi-RCTs assessing the efficacy of PTX with antibiotics (any dose or duration) for treatment of suspected or confirmed sepsis or NEC in neonates. We included three comparisons: (1) PTX with antibiotics compared to placebo or no intervention with antibiotics; (2) PTX with antibiotics compared to PTX with antibiotics and adjunct treatments such as immunoglobulin M-enriched intravenous immunoglobulin (IgM-enriched IVIG); (3) PTX with antibiotics compared to adjunct treatments such as IgM-enriched IVIG with antibiotics.

DATA COLLECTION AND ANALYSIS

We reported typical risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) for continuous outcomes derived from a fixed-effect model of meta-analysis. We calculated the number needed to treat for an additional beneficial outcome (NNTB) if there was a statistically significant reduction in RD.

MAIN RESULTS

We identified no new studies for this update. We included six RCTs (416 neonates). All of the included studies examined neonates with sepsis; we identified no studies on neonates with NEC. Four of the six trials had high risk of bias for at least one risk of bias domain. Comparison 1: PTX with antibiotics compared to placebo with antibiotics, or antibiotics alone, in neonates with sepsis may reduce all-cause mortality during hospital stay (typical RR 0.57, 95% CI 0.35 to 0.93; typical RD -0.08, 95% CI -0.14 to -0.01; NNTB 13, 95% CI 7 to 100; 6 studies, 416 participants, low-certainty evidence) and may decrease length of hospital stay (LOS) (MD -7.74, 95% CI -11.72 to -3.76; 2 studies, 157 participants, low-certainty evidence). The evidence is very uncertain that PTX with antibiotics compared to placebo or no intervention results in any change in chronic lung disease (CLD) (RR 1.50, 95% CI 0.45 to 5.05; 1 study, 120 participants, very low-certainty evidence), severe intraventricular haemorrhage (sIVH) (RR 0.75, 95% CI 0.28 to 2.03; 1 study, 120 participants, very low-certainty evidence), periventricular leukomalacia (PVL) (RR 0.50, 95% CI 0.10 to 2.63; 1 study, 120 participants, very low-certainty evidence), NEC (RR 0.56, 95% CI 0.29 to 1.06; 6 studies, 405 participants, very low-certainty evidence), or retinopathy of prematurity (ROP) (RR 0.40, 95% CI 0.08 to 1.98; 1 study, 120 participants, very low-certainty evidence) in neonates with sepsis. Comparison 2: the evidence is very uncertain that PTX with antibiotics compared to PTX with antibiotics and IgM-enriched IVIG has any effect on mortality (RR 0.71, 95% CI 0.24 to 2.10; 102 participants, 1 study, very low-certainty evidence) or development of NEC in neonates with sepsis (RR 1.33, 95% CI 0.31 to 5.66; 1 study, 102 participants, very low-certainty evidence). The outcomes of CLD, sIVH, PVL, LOS, and ROP were not reported. Comparison 3: the evidence is very uncertain that PTX with antibiotics compared to IgM-enriched IVIG with antibiotics has any effect on mortality (RR 1.25, 95% CI 0.36 to 4.39; 102 participants, 1 study, very low-certainty evidence) or development of NEC (RR 1.33, 95% CI 0.31 to 5.66; 102 participants, 1 study, very low-certainty evidence) in neonates with sepsis. The outcomes of CLD, sIVH, PVL, LOS, and ROP were not reported. All of the included studies evaluated adverse effects due to PTX, but none were reported in the intervention group in any of the comparisons.

AUTHORS' CONCLUSIONS

Low-certainty evidence suggests that adjunct PTX therapy in neonatal sepsis may decrease mortality and length of hospital stay without any adverse effects. The evidence is very uncertain if PTX with antibiotics compared to PTX with antibiotics and IgM-enriched IVIG, or PTX with antibiotics compared to IgM-enriched IVIG with antibiotics, has any effect on mortality or development of NEC. We encourage researchers to undertake well-designed multicentre trials to confirm or refute the effectiveness and safety of pentoxifylline in reducing mortality and morbidity in neonates with sepsis or NEC.

Pentoxifylline Effects on Hospitalized COVID-19 Patients with Cytokine Storm Syndrome: A Randomized Clinical Trial

COVID-19 is a fatal, fast-spreading pandemic, and numerous attempts are being made around the world to understand and manage the disease. COVID-19 patients may develop a cytokine-release syndrome, which causes serious respiratory diseases and, in many cases, death. The study examined the feasibility of employing legally available anti-inflammatory pentoxifylline (PTX), a low toxicity and cost medication, to mitigate the hyper-inflammation caused by COVID-19. Thirty adult patients who tested positive for SARS-CoV2 were hospitalized owing to the cytokine storm syndrome. They were given 400 mg of pentoxifylline orally TID according to the standard COVID-19 protocol of the Egyptian Ministry of Health. Besides this, a group of thirty-eight hospitalized COVID-19 patients who received the standard COVID-19 protocol was included in the study as a control group. The outcomes included laboratory test parameters, clinical improvements, and number of deaths in both groups. After receiving PTX, all patients showed a significant improvement in C reactive protein (CRP), and interleukin-6 (IL-6) levels at p < 0.01 and p = 0.004, respectively, while there was an increase in total leukocyte count (TLC) and neutrophil-to-leucocyte ratio (NLR) at p < 0.01 compared to their baseline levels. The D-dimer level showed a significant increase in the treatment group at p < 0.01, while showing no statistically significant difference in the control group. The median initial ALT (42 U/L) in the treatment group showed a decrease compared to the control group (51 U/L). No statistical significance was reported regarding clinical improvement, length of stay, and death percentages between the two groups. Our results showed no significant improvement of PTX over controls in clinical outcomes of hospitalized COVID-19 patients. Nevertheless, PTX displayed a positive effect on certain inflammatory biomarkers.

Protective effects of pentoxifylline against chlorine-induced acute lung injury in rats

OBJECTIVE

Chlorine is a chemical threat agent that can be harmful to humans. Inhalation of high levels of chlorine can lead to acute lung injury (ALI). Currently, there is no satisfactory treatment, and effective antidote is urgently needed. Pentoxifylline (PTX), a methylxanthine derivative and nonspecific phosphodiesterase inhibitor, is widely used for the treatment of vascular disorders. The present study was aimed to investigate the inhibitory effects of PTX on chlorine-induced ALI in rats.

METHODS

Adult male Sprague-Dawley rats were exposed to 400 ppm Cl₂ for 5 min. The histopathological examination was carried out and intracellular reactive oxygen species (ROS) levels were measured by the confocal laser scanning system. Subsequently, to evaluate the effect of PTX, a dose of 100 mg/kg was administered. The activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG) and lactate dehydrogenase (LDH) were determined by using commercial kits according to the manufacturer's instructions. Western blot assay was used to detect the protein expressions of SOD1, SOD2, catalase (CAT), hypoxia-inducible factor (HIF)-1α, vascular endothelial growth factor (VEGF), occludin, E-cadherin, bcl-xl, LC 3, Beclin 1, PTEN-induced putative kinase 1 (PINK 1) and Parkin.

RESULTS

The histopathological examination demonstrated that chlorine could destroy the lung structure with hemorrhage, alveolar collapse, and inflammatory infiltration. ROS accumulation was significantly higher in the lungs of rats suffering from inhaling chlorine (P<0.05). PTX markedly reduced concentrations of MAD and GSSG, while increased GSH (P<0.05). The protein expression levels of SOD1 and CAT also decreased (P<0.05). Furthermore, the activity of LDH in rats treated with PTX was significantly decreased compared to those of non-treated group (P<0.05). Additionally, the results also showed that PTX exerted an inhibition effect on protein expressions of HIF-1α, VEGF and occludin, and increased the level of E-cadherin (P<0.05). While the up-regulation of Beclin 1, LC 3II/I, Bcl-xl, and Parkin both in the lung tissues and mitochondria, were found in PTX treated rats (P<0.05). The other protein levels were decreased when treated with PTX (P<0.05).

CONCLUSION

PTX could ameliorate chlorine-induced lung injury via inhibition effects on oxidative stress, hypoxia and autophagy, thus suggesting that PTX could serve as a potential therapeutic approach for ALI.

A raising dawn of pentoxifylline in management of inflammatory disorders in Covid-19

The existing pandemic viral infection caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) leads to coronavirus disease 2019 (Covid-19). SARS-CoV-2 exploits angiotensin-converting enzyme 2 (ACE2) as an entry-point into affected cells and down-regulation of ACE2 by this virus triggers the release of pro-inflammatory cytokines and up-regulation of angiotensin II. These changes may lead to hypercytokinemia and the development of cytokine storm with the development of acute lung injury and acute respiratory distress syndrome. Different repurposed had been in use in the management of Covid-19, one of these agents is pentoxifylline (PTX) which has anti-inflammatory and antioxidant properties. Therefore, the objective of the present mini-review is to highlight the potential role of PTX in Covid-19 regarding its anti-inflammatory and antioxidant effects. PTX is a non-selective phosphodiesterase inhibitor that increases intracellular cyclic adenosine monophosphate which stimulates protein kinase A and inhibits leukotriene and tumor necrosis factor. PTX has antiviral, anti-inflammatory and immunomodulatory effects, thus it may attenuate SARS-CoV-2-induced hyperinflammation and related complications. As well, PTX can reduce hyper-viscosity and coagulopathy in Covid-19 through increasing red blood cell deformability and inhibition of platelet aggregations. In conclusion, PTX is a non-selective phosphodiesterase drug, that has anti-inflammatory and antioxidant effects thereby can reduce SARS-CoV-2 infection-hyperinflammation and oxidative stress. Besides, PTX improves red blood cells (RBCs) deformability and reduces blood viscosity so can mitigate Covid-19-induced hyper-viscosity and RBCs hyper-aggregation which is linked with the development of coagulopathy. Taken together, PTX seems to be an effective agent against Covid-19 severity.

Laminitis Updates: Sepsis/Systemic Inflammatory Response Syndrome-Associated Laminitis

Sepsis or systemic inflammatory response syndrome (SIRS) -associated laminitis is a sequela to primary inflammatory conditions (eg, colitis, ischemic intestinal injury, pneumonia, metritis) and results from a dysregulated systemic inflammatory response that ultimately affects the digital lamellae. Local chemokine production, leukocyte migration, and proinflammatory mediator production occur within the lamellae that can lead to catastrophic lamellar failure. Controlling the primary disease, providing supportive care and anti-inflammatory therapy, applying digital cryotherapy, and providing mechanical support are cornerstones to the prevention of sepsis/SIRS-associated laminitis. Novel therapies targeting specific signaling pathways may provide additional therapeutic options in the future.

Influence of Anemia on Postoperative Cognitive Function in Patients Undergo Hysteromyoma Surgery

Cognitive dysfunction is a common disease in aging population. This study aims to compare the influence of different degrees of anemia on the cognitive function of patients undergo hysteromyoma surgery. Sixty-one patients aged 18-60 years who underwent uterine fibroid surgery in the Second Affiliated Hospital of Shantou University Medical College from March 2019 to December 2020 were selected for this study. Patients were divided into three groups: group normal (Group N, patients have no anemia), group of mild anemia (Group Mi, patients have mild anemia) and group of moderate anemia (Group Mo, patients had moderate anemia). Combined spinal and epidural anesthesia were administered. Cognitive function tests were performed 1 day before the surgery and repeated at the 5th and 30th days after surgery. Peripheral venous blood samples from patients were collected before the surgery, right after surgery and at the 24th and 72nd hours after surgery. The contents of S-100β, IL-6, TNF-α and IL-1β in serum samples were determined by ELISA. It was found that there were no significant differences in general characteristics of patients among Group N, Group Mi and Group Mo (p > 0.05). Nine patients developed postoperative cognitive dysfunction after surgery, and the incidence was 14.75% (9/61). The incidence of postoperative cognitive dysfunction (POCD) was 40% in Group Mo, which was higher than that in Group N and Group Mi. The difference was statistically significant (p < 0.05). Inflammatory factors in patients with POCD were higher in post-surgery than before-surgery (p < 0.05), while there was no statistical significance in the difference of inflammatory factors of patients without POCD before and after surgery (p > 0.05). Taken together, this study suggested that moderate anemia could be a risk factor of POCD in patients undergoing hysteromyoma surgeries. This study will help surgeons developing measures for preventing the occurrence of POCD.

Pentoxifylline: A Drug with Antiviral and Anti-Inflammatory Effects to Be Considered in the Treatment of Coronavirus Disease 2019

In December 2019, a new coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged from China, causing pneumonia outbreaks first in the Wuhan region and has now spread worldwide. There are no specific drugs for the disease caused by this virus, coronavirus disease 2019 (COVID-19). Considering that new synthesized drugs cannot be applied immediately to patients, conventional drug in new use is a feasible solution. Chloroquine, remdesivir, favipiravir, lopinavir, ribavirin, and ritonavir have shown efficacy to inhibit coronavirus in vitro. Pentoxifylline, a drug with anti-inflammatory, immunomodulatory, and bronchodilatory effects, has previously been shown to inhibit several viral infections. Immunological studies have shown that most patients with severe COVID-19 exhibit substantially elevated serum levels of pro-inflammatory cytokines. Pentoxifylline is a phosphodiesterase inhibitor that increases the levels of cyclic adenosine monophosphate, which in turn activates protein kinase, leading to a reduction in the synthesis of pro-inflammatory cytokines and immune cell migration. Here, we propose pentoxifylline, a drug with low cost and toxicity, as a possible treatment for COVID-19 based on its interesting properties.

Treatment of COVID-19 with pentoxifylline: Could it be a potential adjuvant therapy?

The world is facing a viral pandemic of a new coronavirus called COVID‐19. Pentoxifylline is a methyl‐xanthine derivative and it inhibits the phosphodiesterase IV (PDE IV). This drug is known for its unique features as an immunomodulatory and anti‐inflammatory agent, also it could have antiviral affects. This is a scoping review, in which all related articles on COVID‐19 and the probable benefits of Pentoxifylline against COVID‐19 pathogenesis, in Medline, Scopus, Web of Sciences, and Google Scholar up to 20 March 2020 with proper keywords including: pentoxifylline, Pentoxil, COVID‐19, coronavirus, treatment, anti‐inflammatory, immunomodulatory, antifibrosis, oxygenation, circulation, bronchodilator, ARDS, and organ failure. We found many confirmatory data on proper efficacy of pentoxifylline on controlling COVID‐19 and its consequences. The antiviral, anti‐inflammatory, anti‐oxidative, immune‐modulatory, bronchodilator and respiratory supportive effects and protective roles in organ failures of PTX, along with its main functions means better circulation‐oxygenation properties, low price and safety, make it a promising drug to be considered for COVID‐19 treatment, especially as an adjuvant therapy in combination with other drugs.

Hypertonic saline and pentoxifylline enhance survival, reducing apoptosis and oxidative stress in a rat model of strangulated closed loop small bowel obstruction

OBJECTIVES

Intestinal obstruction has a high mortality rate when therapeutic treatment is delayed. Resuscitation in intestinal obstruction requires a large volume of fluid, and fluid combinations have been studied. Therefore, we evaluated the effects of hypertonic saline solution (HS) with pentoxifylline (PTX) on apoptosis, oxidative stress and survival rate.

METHODS

Wistar rats were subjected to intestinal obstruction and ischemia through a closed loop ligation of the terminal ileum and its vessels. After 24 hours, the necrotic bowel segment was resected, and the animals were randomized into four groups according to the following resuscitation strategies: Ringer's lactate solution (RL) (RL-32 ml/kg); RL+PTX (25 mg/kg); HS+PTX (HS, 7.5%, 4 ml/kg), and no resuscitation (IO-intestinal obstruction and ischemia). Euthanasia was performed 3 hours after resuscitation to obtain kidney and intestine samples. A malondialdehyde (MDA) assay was performed to evaluate oxidative stress, and histochemical analyses (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling [TUNEL], Bcl-2 and Bax) were conducted to evaluate kidney apoptosis. Survival was analyzed with another series of animals that were observed for 15 days.

RESULTS

PTX in combination with RL or HS reduced the MDA levels (nmol/mg of protein), as follows: kidney IO=0.42; RL=0.49; RL+PTX=0.31; HS+PTX=0.34 (p<0.05); intestine: IO=0.42; RL=0.48; RL+PTX=0.29; HS+PTX=0.26 (p<0.05). The number of labeled cells for TUNEL and Bax was lower in the HS+PTX group than in the other groups (p<0.05). The Bax/Bcl-2 ratio was lower in the HS+PTX group than in the other groups (p<0.05). The survival rate on the 15th day was higher in the HS+PTX group (77%) than in the RL+PTX group (11%).

CONCLUSION

PTX in combination with HS enhanced survival and attenuated oxidative stress and apoptosis. However, when combined with RL, PTX did not reduce apoptosis or mortality.

Response of antimicrobial peptides from porcine neutrophils to pentoxifylline and antigens from Gram negative and Gram positive bacteria

Neutrophils, the main component of the defense against invading organisms have also been implicated in tissue damage in numerous inflammatory conditions. Neutrophil products can degrade the extracellular matrix and when excessively released are thought to cause some disorders. As it is known, pentoxifylline (PTX) can suppress a range of neutrophil responses. Cathelicidins are components of the early host defenses against infection, however, in most cases cleavage with elastase is necessary to obtain active forms. Thus, the aim of our study was to assess the usage of PTX as a factor which could inhibit some neutrophil functions, and to assess if PTX can lead to the impairment of the release from these cells active cathelicidins. For these purposes we determined neutrophil activity as well as expression of cathelicidins from porcine neutrophils in cultures under the influence of PTX. PTX exerted an inhibitory effect on elastase and MPO release from neutrophils. At lower concentrations of PTX, ALP release was inhibited both in cultures stimulated with PTX+fMLP and with PTX+LPS. Inhibition of superoxide generation was insignificant, whereas a decrease of NO production was noted. The MALDI TOF analysis revealed that in all cultures stimulated with PTX+fLMP and PTX+LPS there was no inhibition of the release of cathelicidins in comparison with cultures stimulated only with fMLP and only with LPS. Our study proved that although PTX in porcine neutrophils is able to suppress many neutrophil functions, the expression of cathelicidins is maintained.

Pulmonary Protection Strategies in Cardiac Surgery: Are We Making Any Progress?

Pulmonary dysfunction is a common complication of cardiac surgery. The mechanisms involved in the development of pulmonary dysfunction are multifactorial and can be related to the activation of inflammatory and oxidative stress pathways. Clinical manifestation varies from mild atelectasis to severe respiratory failure. Managing pulmonary dysfunction postcardiac surgery is a multistep process that starts before surgery and continues during both the operative and postoperative phases. Different pulmonary protection strategies have evolved over the years; however, the wide acceptance and clinical application of such techniques remain hindered by the poor level of evidence or the sample size of the studies. A better understanding of available modalities and/or combinations can result in the development of customised strategies for the different cohorts of patients with the potential to hence maximise patients and institutes benefits.

Pentoxifylline for treatment of sepsis and necrotizing enterocolitis in neonates

BACKGROUND

Mortality and morbidity due to neonatal sepsis and necrotizing enterocolitis (NEC) remain high despite the use of potent antimicrobial agents. Agents that modulate inflammation may improve outcomes. Pentoxifylline, a phosphodiesterase inhibitor, is one such agent.

OBJECTIVES

Our primary objectives were :1.To assess the effect of intravenous pentoxifylline as an adjunct to antibiotic therapy on mortality and morbidity in neonates with suspected or confirmed sepsis.2.To assess the effect of intravenous pentoxifylline as an adjunct to antibiotic therapy on mortality and morbidity in neonates with NEC.

SEARCH METHODS

We searched the Cochrane Neonatal Review Group Specialized Register, CENTRAL (The Cochrane Library Issue 2, 2014), EMBASE (January 1980 to May 2014), PubMed (January 1966 to May 2014), CINAHL (January 1982 to May 2014), Science Citation Index (January 1990 to May 2014), and BIOSIS (January 1992 May 2014) in May 2014. We checked references and cross-references from identified studies. We handsearched abstracts from the proceedings of the Pediatric Academic Societies Meetings (from January 1990 to May 2014). We placed no restrictions on language.

SELECTION CRITERIA

We included randomised or quasi-randomised trials assessing the efficacy of pentoxifylline as an adjunct to antibiotics for treatment of suspected or confirmed sepsis or NEC in neonates.

DATA COLLECTION AND ANALYSIS

We reported typical risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CI) using fixed-effect model for dichotomous outcomes and mean difference (MD) for continuous outcomes. We calculated the number needed to treat for an additional beneficial outcome (NNTB) if there was a statistically significant reduction in RD.

MAIN RESULTS

Pentoxifylline used as an adjunct to antibiotics in neonates with sepsis decreased all-cause mortality during hospital stay (typical RR 0.57, 95% CI 0.35 to 0.93; typical RD -0.08, 95% CI -0.14 to -0.01; NNTB 13, 95% CI 7 to 100; 6 studies, 416 participants, low-quality evidence). Subgroup analyses revealed decrease in mortality in preterm infants, infants with confirmed sepsis, and infants with gram-negative sepsis (low-quality evidence, four studies). Pentoxifylline decreased length of hospital stay (MD -7.59 days, 95% CI -11.65 to -3.52; 2 studies, 148 participants, low-quality evidence). Pentoxifylline did not change the risk of development of NEC, chronic lung disease, severe intraventricular haemorrhage, retinopathy of prematurity, or periventricular leukomalacia in neonates with sepsis (one to two studies, very low-quality evidence). Pentoxifylline therapy compared to pentoxifylline and immunoglobulin M-enriched intravenous immunoglobulin or immunoglobulin M-enriched intravenous immunoglobulin alone did not change mortality or development of NEC in neonates with sepsis (one study, very low-quality evidence). We noted no adverse effects due to pentoxifylline. We identified no trials evaluating pentoxifylline treatment for NEC.

AUTHORS' CONCLUSIONS

Low-quality evidence from six small studies suggests that pentoxifylline therapy as an adjunct to antibiotics in neonatal sepsis decreases mortality without any adverse effects. We encourage researchers to undertake large, well-designed multicentre trials to confirm or refute the effectiveness of pentoxifylline in reducing mortality and morbidity in neonates with sepsis or NEC.

Drug therapy for the prevention and treatment of bronchopulmonary dysplasia

INTRODUCTION

As more infants are surviving at younger gestational ages, bronchopulmonary dysplasia (BPD) remains as a frequent neonatal complication occurring after preterm birth. The multifactorial nature of the disease process makes BPD a challenging condition to treat. While multiple pharmacologic therapies have been investigated over the past two decades, there have been limited advances in the field. Often multiple therapies are used concurrently without clear evidence of efficacy, with potential for significant side effects from drug-drug interactions.

METHODS

Systematic literature review.

CONCLUSION

Although there is physiologic rationale for the use of many of these therapies, none of them has single-handedly altered the incidence, severity, or progression of BPD. Future research should focus on developing clinically significant end-points (short and long term respiratory assessments), investigating biomarkers that accurately predict risk and progression of disease, and creating appropriate stratification models of BPD severity. Applying a multi-modal approach to the study of new and existing drugs should be the most effective way of establishing the optimal prevention and treatment regimens for BPD.

Therapeutic effect of intravenous infusion of perfluorocarbon emulsion on LPS-induced acute lung injury in rats

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) are the leading causes of death in critical care. Despite extensive efforts in research and clinical medicine, mortality remains high in these diseases. Perfluorocarbon (PFC), a chemical compound known as liquid ventilation medium, is capable of dissolving large amounts of physiologically important gases (mainly oxygen and carbon dioxide). In this study we aimed to investigate the effect of intravenous infusion of PFC emulsion on lipopolysaccharide (LPS) induced ALI in rats and elucidate its mechanism of action. Forty two Wistar rats were randomly divided into three groups: 6 rats were treated with saline solution by intratracheal instillation (control group), 18 rats were treated with LPS by intratracheal instillation (LPS group) and the other 18 rats received PFC through femoral vein prior to LPS instillation (LPS+PFC group). The rats in the control group were sacrificed 6 hours later after saline instillation. At 2, 4 and 6 hours of exposure to LPS, 6 rats in the LPS group and 6 rats in LPS+PFC group were sacrificed at each time point. By analyzing pulmonary pathology, partial pressure of oxygen in the blood (PaO2) and lung wet-dry weight ratio (W/D) of each rat, we found that intravenous infusion of PFC significantly alleviated acute lung injury induced by LPS. Moreover, we showed that the expression of pulmonary myeloperoxidase (MPO), intercellular adhesion molecule-1 (ICAM-1) of endothelial cells and CD11b of polymorphonuclear neutrophils (PMN) induced by LPS were significantly decreased by PFC treatment in vivo. Our results indicate that intravenous infusion of PFC inhibits the infiltration of PMNs into lung tissue, which has been shown as the core pathogenesis of ALI/ARDS. Thus, our study provides a theoretical foundation for using intravenous infusion of PFC to prevent and treat ALI/ARDS in clinical practice.

Lipoxin A4 attenuation of endothelial inflammation response mimicking pancreatitis-induced lung injury

Lipoxins (LXs) and their analogues are known to display potent anti-inflammatory actions. Previously, we reported that lipoxin A4 (LXA4) possessed powerful anti-inflammatory properties in acute pancreatitis in rats and that it may ameliorate the concomitant acute lung injury by reducing cytokine generation and inhibiting neutrophil activation. Considering that the vascular endothelium plays an important role during adherence, migration and activation of leukocytes, the present study was designed to investigate the effects of LXA4 on the inflammatory response induced by tumor necrosis factor α (TNF-α) in human pulmonary microvascular endothelial cells (HPMECs) and explore the potential mechanisms involved in these processes. We found that LXA4 markedly down-regulated the expression of monocyte chemotactic protein-1 (MCP-1), E-selectin, and interleukin-6 (IL-6) mRNA, as well as intercellular adhesion molecule-1 (ICAM-1) in TNF-α-exposed HPMECs. Moreover, LXA4 inhibited the phosphorylation and nuclear translocation of nuclear factor-κB/p65 (NF-κB/p65) and phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) in HPMECs following TNF-α stimulation. Heme oxygenase-1 (HO-1), a cytoprotective enzyme, was up-regulated by LXA4 in both non- and TNF-α-stimulated HPMECs. In conclusion, the protective effects of LXA4 to ALI may be executed through inhibition inflammation pathways of NF-κB and p38 MAPK and up-regulation of cytoprotective HO-1.

Protective effects of pentoxifylline in pulmonary inflammation are adenosine receptor A2A dependent

Pentoxifylline (PTX) has been shown to exert anti-inflammatory effects in experimental acute lung injury. However, results in humans were controversial. Recent in vitro studies suggested that the adenosine receptor A2A may be required for PTX to be effective. Therefore, we studied the association between A2A and PTX in a murine model of LPS-induced pulmonary inflammation. PTX treatment (10 mg/kg) reduced cellular influx (by 40%), microvascular permeability (30%), and the release of chemotactic cytokines into the alveolar space (TNF-α 60%, IL-6 60%, and CXCL2/3 53%, respectively). These protective effects were abolished completely in A2A(-/-) mice and in wild-type mice that had been treated with the selective A2A antagonist (1 mg/kg), but effects were not different in mice with altered adenosine levels. In vitro transmigration assays revealed a pivotal role of the endothelium in PTX-mediated PMN migration, with a reduction of 50% (2 mM PTX). This effect was also A2A dependent. Further, oxidative burst of human PMNs was A2A-dependently reduced by 53% after PTX treatment. In summary, PTX exhibits its anti-inflammatory effects in LPS-induced lung injury through an A2A-dependent pathway. These results will help to better understand previous conflicting data on PTX in inflammation and will direct further studies to consider the predominant role of A2A.

Uncovering the neuroenteric-pulmonary axis: vagal nerve stimulation prevents acute lung injury following hemorrhagic shock

AIMS

Trauma/hemorrhagic shock (T/HS) induced gut injury is known to initiate a systemic inflammatory response which can lead to secondary lung injury. We have shown that vagal nerve stimulation (VNS) protects intestinal epithelial integrity after a severe burn insult. We hypothesize that VNS will protect the lung from injury following T/HS by preventing intestinal barrier failure.

MAIN METHODS

Male Balb/c mice were subjected to a T/HS model with and without cervical VNS. Intestinal injury was evaluated by measuring changes in gut barrier function and tight junction protein localization. Lung injury was evaluated using histology and markers of lung inflammation. Using NF-kB-luciferase (NF-kB-luc) transgenic mice, NF-kb-DNA binding was measured by photon emission analysis at 4 after injury.

KEY FINDINGS

T/HS is associated gut injury characterized by histologic injury, increased epithelial permeability, and altered localization of gut tight junction proteins. Cervical VNS prevented the T/HS-induced changes in gut barrier integrity. Gut injury after T/HS was associated with acute lung injury at 24 h characterized by histologic injury, increased number of MPO positive stained cells and MPO enzymatic activity, and increased ICAM-1 expression in lung endothelium. VNS decreased T/HS-induced lung injury with a marked decrease in lung inflammation compared to T/HS alone. Lungs harvested from NF-kB-luc mice at 4h post VNS+T/HS demonstrated decreased DNA binding of NF-kB compared to T/HS alone as measured by changes in bioluminescence.

SIGNIFICANCE

VNS is effective in protecting against acute lung injury caused by hemorrhagic shock through its ability to prevent gut barrier dysfunction.

Pentoxifylline and prevention of hyperoxia-induced lung -injury in neonatal rats

INTRODUCTION

Oxygen exposure plays an important role in the pathogenesis of bronchopulmonary dysplasia (BPD). The phosphodiesterase inhibitor pentoxifylline (PTX) has anti-inflammatory and antifibrotic effects in multiple organs. It was hypothesized that PTX would have a protective effect on hyperoxia-induced lung injury (HILI).

METHODS

Newborn Sprague-Dawley rats were exposed to >95% oxygen (O(2)) and injected subcutaneously with normal saline (NS) or PTX (75 mg/kg) twice a day for 9 d. NS-injected, room air-exposed pups were controls. At days 4 and 9, lung tissue was collected to assess edema, antioxidant enzyme (AOE) activities, and vascular endothelial growth factor (VEGF) expression. At day 9, pulmonary macrophage infiltration, vascularization, and alveolarization were also examined.

RESULTS

At day 9, treatment with PTX significantly increased survival from 54% to 88% during hyperoxia. Treatment with PTX significantly decreased lung edema and macrophage infiltration. PTX treatment increased lung AOE activities including those of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX). Furthermore, PTX treatment also increased the gene expression of VEGF189 and VEGF165, increased VEGF protein expression, and improved pulmonary vascularization.

DISCUSSION

These data indicate that the reduced lung edema and inflammation, increased AOE activities, and improved vascularization may be responsible for the improved survival with PTX during hyperoxia. PTX may be a potential therapy in reducing some of the features of BPD in preterm newborns.

Pentoxifylline for treatment of sepsis and necrotizing enterocolitis in neonates

BACKGROUND

Mortality and morbidity due to neonatal sepsis and necrotizing enterocolitis (NEC) is high despite the use of potent antimicrobial agents. Agents that modulate inflammation may improve outcomes. Pentoxifylline, a phosphodiesterase inhibitor, is one such agent.

OBJECTIVES

The primary objectives were to assess the effect on mortality and the safety of intravenous pentoxifylline as an adjunct to antibiotic therapy in neonates with suspected or confirmed sepsis and NEC.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2011), MEDLINE, EMBASE and CINAHL, Science Citation Index for articles referencing Lauterbach 1996, proceedings of the Pediatric Academic Societies (1990 to 2011), BIOSIS (1992 to 2011), conference proceedings (1992 to 2011), ongoing trials and reference lists of identified RCTs were searched in July 2011.

SELECTION CRITERIA

Randomised or quasi-randomised trials assessing the efficacy of pentoxifylline as an adjunct to antibiotics for treatment of suspected or confirmed sepsis or NEC in neonates were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted information for the outcomes of interest. Typical relative risk (RR) and risk difference (RD) with 95% confidence intervals (CI) using fixed effects model are reported for dichotomous outcomes and mean differences for continuous outcomes. NNT was calculated for outcomes for which there was a statistically significant reduction in RD.

MAIN RESULTS

In four randomised controlled trials, 227 neonates with suspected or confirmed sepsis were randomised to pentoxifylline or placebo. Pentoxifylline therapy significantly decreased "all cause mortality during hospital stay" in the overall population of infants with sepsis [typical RR 0.40 (95%CI 0.20 to 0.77); typical RD -0.15 (95%CI -0.26 to -0.05); NNT 7 (95%CI 4 to 20)]. Subgroup analyses revealed significant reduction in mortality in preterm infants, infants with confirmed sepsis and gram-negative sepsis. Pentoxifylline treatment significantly decreased length of hospital stay [mean difference -11.20 [95%CI -22.09 to -0.31] but not development of NEC in neonates with sepsis [typical RR 0.29 (95%CI 0.07 to 1.24); typical RD -0.20 (95%CI -0.41 to 0.01)]. No adverse effects due to pentoxifylline were noted. No completed trial of treatment with pentoxifylline for treatment of NEC was identified.

AUTHORS' CONCLUSIONS

Current evidence from four small studies suggests that the use of pentoxifylline as an adjunct to antibiotics in neonatal sepsis decreases mortality without any adverse effects. Researchers are encouraged to undertake large well-designed multicenter trials to confirm or refute the effectiveness of pentoxifylline in reducing mortality and adverse outcomes in neonates with suspected or confirmed neonatal sepsis and NEC.

The relative efficacy of aminoguanidine and pentoxifylline in modulating endotoxin-induced cardiac stress

This study investigates the effect of aminoguanidine (AG), a selective inducible nitric oxide synthase (iNOS) inhibitor, and pentoxifylline (PTX), a tumour necrosis factor-alpha (TNF-α) inhibitor, on lipopolysaccharide (LPS)-induced cardiac stress. Rats were divided into four groups: group I served as a control, group II (LPS) received a single intraperitoneal injection of LPS (10 mg·kg(-1) ), group III (LPS+AG) and group IV (LPS+PTX) were injected with either AG (100 mg·kg(-1) ) or PTX (150 mg·kg(-1) ) intraperitoneally 10 days prior to LPS administration. Normalization of cardiac levels of nitrite/nitrate (NO(X) ), malondialdehyde (MDA), glutathione (GSH), heme oxygenase-1 (HO-1), glutathione peroxidase (GPx) and Na(+) , K(+) -ATPase activities was evident in the AG group. Both AG and PTX decreased the elevated serum TNF-α levels, the activities of lactate dehydrogenase (LDH), creatine kinase (CK) and cardiac myeloperoxidase (MPO). The levels of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and phosphocreatine (PCr) were enhanced following AG and PTX pretreatments. Calcium (Ca(2+) ) levels were altered, and the histopathological observations supported the described results. Conclusively, the study highlights the cardioprotective potential of AG and PTX with superior results from AG. These findings reveal the relative contribution of nitric oxide and TNF-α to oxidative stress and energy failure during endotoxemia.

Biomarkers in acute lung injury: insights into the pathogenesis of acute lung injury

Studies of potential biomarkers of acute lung injury (ALI) have provided information relating to the pathophysiology of the mechanisms of lung injury and repair. The utility of biomarkers remains solely among research tools to investigate lung injury and repair mechanisms. Because of lack of sensitivity and specificity, they cannot be used in decision making in patients with ALI or acute respiratory distress syndrome. The authors reviewed known biomarkers in context of their major biologic activity. The continued interest in identifying and studying biomarkers is relevant, as it provides information regarding the mechanisms involved in lung injury and repair and how this may be helpful in identifying and designing future therapeutic targets and strategies and possibly identifying a sensitive and specific biomarker.

The value of the lipopolysaccharide-induced acute lung injury model in respiratory medicine

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a syndrome characterized by pulmonary edema and acute inflammation. Lipopolysaccharide (LPS), a major component in Gram-negative bacteria, has been used to induce ALI/ARDS. LPS-induced animal models highlight ways to explore mechanisms of multiple diseases and provide useful information on the discovery of novel biomarkers and drug targets. However, each model has its own merits and drawbacks. The goal of this article is to summarize and evaluate the results of experimental findings in LPS-induced ALI/ARDS, and the possible mechanisms and treatments elucidated. Advantages and disadvantages of such models in pulmonary research and new directions for future investigations are also discussed.

Adjunctive immunologic interventions in neonatal sepsis

Because of inadequate sample sizes of randomized controlled trials, few immunologic interventions to treat or prevent neonatal sepsis have been reliably evaluated. International collaboration is essential in achieving timely, adequate samples to assess effects on mortality or disability-free survival reliably. Promising or possible therapeutic interventions in severe or gram-negative sepsis include exchange transfusions, pentoxifylline, and IgM-enriched intravenous immunoglobulin. Promising or possible prophylactic interventions include lactoferrin, with or without a probiotic; selenium; early curtailment of antibiotics after sterile cultures; breast milk; and earlier initiation of colostrum in high risk preterm infants. Prophylactic oral probiotics are safe and effective (P<.00001) in reducing all-cause mortality and necrotizing enterocolitis in preterm infants by over half, but do not reduce sepsis.

Do the effects of pentoxifylline on the inflammatory process and pancreatic infection justify its use in acute pancreatitis?

Severe acute pancreatitis is associated with high morbidity and mortality rates. At the present time, no specific therapy has been shown to be uniformly effective in reducing morbidity and mortality in this disease. The aim of this study was to determine the effects of pentoxifylline on the pancreatic and systemic inflammatory process, pancreatic infection, and mortality rate in severe acute pancreatitis in rats.

METHODS

One hundred and twenty male Wistar rats were divided into 3 groups: sham, pancreatitis, and pentoxifylline (acute pancreatitis induction plus administration of 25 mg/kg pentoxifylline). Inflammatory response was measured by histological studies, inflammatory cytokine production (IL-6, IL-10, and TNF-alpha), and mortality rate. Pancreatic infection was evaluated by bacterial cultures expressed in colony-forming units per gram.

RESULTS

Pentoxifylline-treated animals had a statistically significant reduction of inflammatory cytokine levels, pancreatic histological damage, occurrence of bacterial translocation and pancreatic infection (p < 0.05), associated with a significant reduction in mortality rate.

CONCLUSIONS

Pentoxifylline administration in this experimental model of acute pancreatitis reduces local and systemic inflammatory responses and decreases the pancreatic infection and the mortality rate.

Clarithromycin, montelukast, and pentoxifylline combination treatment ameliorates experimental neonatal hyperoxic lung injury

OBJECTIVE

We aimed to assess the efficiency of clarithromycin, montelukast, and pentoxifylline treatments, alone and in combination, in reducing hyperoxic lung injury at the histopathologic level.

METHODS

The experiment was carried out with 47 newborn rat pups divided into six groups during postnatal days 3 to 13. The rats belonging to group 1 were designated as the control group and kept in room air without exposure to hyperoxia. Group 2 (clarithromycin), group 3 (montelukast), group 4 (pentoxifylline), group 5 (clarithromycin + montelukast + pentoxifylline combination), and group 6 (placebo) were kept in plexiglass chamber and exposed to hyperoxia (88-92%) throughout the experiment. Alveolar surface area percentage, fibrosis, and smooth muscle actin expression were assessed in the lungs, which were resected by thoracotomy on postnatal day 14.

RESULTS

Drug treatments, when used separately, were not detected to be superior to placebo with regard to mean alveolar surface area, fibrosis, and smooth muscle actin expression. Combination treatment resulted in significantly higher mean lung area percentages and lower actin scores with respect to the placebo treatment group (64.0% vs. 50.2%, p=0.002; 0 (0-1) vs. 7 (2-12), p=0.005, respectively).

CONCLUSIONS

It was determined that clarithromycin, montelukast, and pentoxifylline combination treatment is superior to placebo treatment in the newborn rat hyperoxic lung injury model. The present study indicates that combination therapy might be successful in bronchopulmonary dysplasia, which has complex pathophysiologic processes and lacks established efficient treatment strategies.

Pentoxifylline attenuates pulmonary inflammation and neutrophil activation in experimental acute pancreatitis

OBJECTIVES

Acute pancreatitis (AP) is associated with a systemic inflammatory response. Pentoxifylline (PTX) has been shown to attenuate neutrophil activation and end-organ injury in shock states such as hemorrhage and sepsis. We hypothesized that PTX would down-regulate AP-induced lung injury.

METHODS

Sprague-Dawley rats underwent catheterization of the pancreatic duct. Acute pancreatitis (n = 7) and AP/PTX animals (n = 7) received a retrograde infusion of 3.5% sodium taurocholate and intravenous treatment with normal saline or normal saline and PTX (25 mg/kg), respectively. Pulmonary neutrophil degranulation and sequestration were determined by zymography and detection of myeloperoxidase. Nuclear factor kappa B and mitogen-activated protein kinase phosphorylation was determined by Western blot. Cytokine-induced neutrophil chemoattractant was quantified by enzyme linked immunosorbent assay.

RESULTS

Pulmonary histologic injury scores were attenuated in the AP/PTX group (P < 0.05). Plasma amylase levels remained unchanged. Pentoxifylline produced a significant decline in myeloperoxidase content and matrix metalloproteinase activity (P < 0.05). The increase in the phosphorylation of pulmonary nuclear factor kappa B, p38 mitogen-activated protein kinase, and extracellular-related signal kinase 1/2 observed after AP was not demonstrated with PTX (P < 0.05). Pentoxifylline supplementation reduced pulmonary cytokine-induced neutrophil chemoattractant levels by 50% (P < 0.05).

CONCLUSIONS

Pentoxifylline significantly attenuated histologic lung injury, pulmonary neutrophil activity, and proinflammatory signaling in a severe model of AP. Therefore, PTX may serve as an adjunct for the treatment of the inflammatory complications of severe AP.

From acute pancreatitis to end-organ injury: mechanisms of acute lung injury

BACKGROUND

Multi-organ dysfunction, and in particular lung injury, is often responsible for the unfavorable outcome of patients with severe acute pancreatitis. Understanding of the mechanisms by which local inflammation in the pancreas leads to end-organ injury is crucial for the development of new therapeutic strategies.

METHODS

A MEDLINE search was performed with the terms "acute pancreatitis," "lung injury," "inflammatory response," "SIRS," and "multi-organ dysfunction." Pertinent articles were selected for analysis.

RESULTS

Modulation of the inflammatory response using a combination of immunomodulatory agents may decrease the incidence of severe pancreatitis-related acute lung injury and acute respiratory distress syndrome.

CONCLUSION

Clinical trials are of utmost importance to establish the validity of such strategies.

Hypertonic saline and pentoxifylline reduces hemorrhagic shock resuscitation-induced pulmonary inflammation through attenuation of neutrophil degranulation and proinflammatory mediator synthesis

BACKGROUND

Ringer's lactate (RL), the current standard resuscitation fluid, potentiates neutrophil activation and is associated with pulmonary inflammation. Resuscitation with hypertonic saline and pentoxifylline (HSPTX) has been shown to attenuate hemorrhagic shock-induced injury when compared with RL. Because the neutrophil plays a major role in postshock inflammation, we hypothesized that HSPTX reduces pulmonary inflammation after resuscitation in comparison to RL.

METHODS

Sprague-Dawley rats underwent controlled shock and were resuscitated with RL (32 mL/kg) or HSPTX (4 mL/kg 7.5% NaCl + pentoxifylline 25 mg/kg). Animals who did not undergo shock or resuscitation served as controls. After 24 hours, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. Cytokine induced neutrophil chemoattractant (CINC) was measured in BALF by enzyme-linked immunosorbent assay. Matrix metalloproteinases (MMP)-2 and -9 were measured by zymography. Hemeoxygenase-1 (HO-1) was assessed by Western blot and immunohistochemistry.

RESULTS

HSPTX resuscitation led to a 62% decrease in CINC levels compared with RL (p < 0.01). BALF MMP-2 expression was attenuated by 11% with HSPTX (p = 0.09). Lung MMP-2 and MMP-9 expression was reduced by 89% (p < 0.01) and 76%, respectively (p < 0.05). Lung HO-1 expression declined by 34% with HSPTX in comparison to RL (p < 0.01), indicating less oxidative injury. Lung immunohistochemistry localized HO-1 to neutrophils, macrophages, and airway epithelial cells.

CONCLUSION

Collectively, the attenuation of pulmonary inflammation with HSPTX after shock when compared with RL is associated with downregulation of neutrophil activation, oxidative stress, and proinflammatory mediator production.

Pentoxifylline fails to attenuate fibrosis in dystrophic (mdx) diaphragm muscle

Fibrosis is a common pathological feature observed in muscle from patients with Duchenne muscular dystrophy and in mdx diaphragm. The purpose of this study was to determine whether pentoxifylline (PTX) treatment for 4 weeks (16 mg/kg/day) could significantly attenuate the process of fibrosis in diaphragm muscle from mdx mice. PTX treatment had no impact on in vitro diaphragm muscle contractile function. In addition, diaphragm muscle hydroxyproline concentration and the level of type I and III collagen and TGF-beta1 mRNA were unaffected by PTX treatment. These findings do not support the use of PTX as an antifibrotic drug for the treatment of muscular dystrophy.

Neutrophil degranulation and the effects of phosphodiesterase inhibition

BACKGROUND

Neutrophils play a major role as the first line in host defense after exposure to bacterial products. However, an exaggerated inflammatory response characterized by overwhelming neutrophil activation can be injurious to the host. Pentoxifylline (PTX), a nonspecific phosphodiesterase inhibitor, has been shown to attenuate neutrophil oxidative burst and decrease proinflammatory mediator synthesis. We hypothesized that PTX down-regulates neutrophil activation by decreasing the surface expression of both CD35 and CD66b, two markers of neutrophil degranulation.

MATERIALS AND METHODS

Venous blood was obtained from three healthy volunteers. Whole blood was incubated with HBSS (control), f-methionyl-leucyl-phenylalanine (fMLP, 1 microM/L), PTX (2 mM/L), or fMLP + PTX. CD35 and CD66b expression were measured by flow cytometry.

RESULTS

fMLP treatment caused a significant increase in CD35 and CD66b expression of when compared to controls (P < 0.01). PTX treatment revealed expression of both markers comparable to the control group. A 38% decrease in CD35 (64 +/- 12 versus 100; P < 0.01) and a 52% decrease in CD66b (48 +/- 7 versus 100; P < 0.01) expression were demonstrated in the fMLP + PTX group when compared to fMLP alone.

CONCLUSION

In addition to the known effects of PTX on neutrophil oxidative burst, PTX also affects neutrophil degranulation, an essential step in enzyme release and subsequent tissue injury. These findings may have clinical relevance in the treatment of disease processes due to inflammation in which primed neutrophils play a role.

HSPTX protects against hemorrhagic shock resuscitation-induced tissue injury: an attractive alternative to Ringer's lactate

BACKGROUND

Conventional fluid resuscitation with Ringer's lactated (RL) activates neutrophils and causes end-organ damage. We have previously shown that HSPTX, a combination of small volume hypertonic saline (HS) and pentoxifylline (PTX), a phosphodiesterase-inhibitor, downregulates in vitro neutrophil activation and proinflammatory mediator synthesis. Herein, we hypothesized that HSPTX decreases end-organ injury when compared with RL in an animal model of hemorrhagic shock.

METHODS

Sprague-Dawley rats were bled to a mean arterial pressure of 35 mm Hg for 1 hour. Animals were divided into 3 groups: sham (no shock, no resuscitation, n = 7), RL (32 mL/kg, n = 7), and HSPTX (7.5% NaCl 4 mL/kg + PTX 25 mg/kg; n = 7). Shed blood was infused after fluid resuscitation. Blood pressure was monitored until the end of resuscitation. Animals were sacrificed at 24 hour after resuscitation. Bronchoalveolar lavage fluid (BALF) was obtained for white cell count (total and differential) and TNF-alpha and IL-1beta levels were measured by ELISA. Lung and intestinal injury at 24 hour were evaluated by histopathology. Organ damage was graded by a pathologist and a score was created (0 = no injury; 3 = severe). Lung neutrophil infiltration was evaluated by MPO immune staining.

RESULTS

There were no differences in mean arterial pressure between groups. At 24 hours, BALF leukocyte count was decreased by 30% in HSPTX animals (p < 0.01). TNF-alpha and IL-1beta levels were markedly decreased in HSPTX-resuscitated animals compared with their RL counterparts (p < 0.01). HSPTX-resuscitated animals (lung injury score = 1.0 +/- 0.4) had markedly decreased acute lung injury compared with RL-treated animals (2.5 +/- 0.3) (p < 0.01). RL resuscitation led to a two-fold increase in lung neutrophil infiltration whereas in HSPTX-treated animals, the number of MPO + cells was similar to sham animals (p < 0.001). Intestinal injury was markedly attenuated by HSPTX (1.1 +/- 0.3) compared with RL animals (2.6 +/- 0.4) (p < 0.001).

CONCLUSIONS

HSPTX, a small volume resuscitation strategy with marked immunomodulatory potential led to a marked decrease in end-organ damage. HSPTX is an attractive alternative to RL in hemorrhagic shock resuscitation.

LPS-Induced Acute Lung Injury is Attenuated by Phosphodiesterase Inhibition: Effects on Proinflammatory Mediators, Metalloproteinases, NF-??B, and ICAM-1 Expression

BACKGROUND

Acute endotoxemia is characterized by an enhanced inflammatory response. Pentoxifylline (PTX), a phosphodiesterase inhibitor, has been shown to decrease TNF-alpha levels and to down-regulate neutrophil activation, likely because of increases in intracellular cyclic AMP. Its effects on lipopolysaccharide (LPS) induced lung injury, more specifically on tissue neutrophil infiltration and degranulation, adhesion molecule expression, and transcriptional factor activation, have not been fully investigated. We postulated that PTX treatment in acute endotoxemia downregulates the inflammatory response and may decrease lung injury.

METHODS

Male Sprague-Dawley rats were randomized into three groups: Sham (saline i.v.), LPS (5 mg/kg i.v.), and PTX + LPS (25 mg/kg and 5 mg/kg i.v., respectively; concomitant injection). After 4 hours, bronchoalveolar lavage fluid (BAL), plasma, and lungs were sampled. BAL IL-8 (ELISA), BAL MMP-2, plasma MMP-9, and BAL MMP-9 (Zymography) were measured. Lung histology (H&E), in addition to lung MPO, ICAM-1, and NF-kappaB expression evaluated by immunohistochemistry were analyzed. Lung NF-kappaB DNA binding was evaluated by electrophoretic mobility shift assay.

RESULTS

PTX treatment decreased BAL IL-8 levels, BAL MMP-2, and plasma MMP-9 activity. Lung neutrophil infiltration (MPO), ICAM-1 expression and NF-kappaB activation were decreased by PTX. In addition, PTX treatment caused a marked attenuation of LPS-induced lung injury.

CONCLUSIONS

Phosphodiesterase inhibition by PTX attenuates LPS-induced end-organ injury. In addition, proinflammatory cytokine production is also downregulated, likely because of the marked attenuation of NF-kappaB DNA binding and activation.

Phosphodiesterase Inhibition Attenuates Stored Blood-Induced Neutrophil Activation: A Novel Adjunct to Blood Transfusion

BACKGROUND

Activated neutrophils play a central role in the pathogenesis of ARDS and multiple organ failure (MOF). Transfusion of packed red blood cells (PRBCs) is an independent risk factor in the development of ARDS and MOF. It has been postulated that factors present in the supernatant of PRBCs activate neutrophils. The magnitude of neutrophil activation is dependent on the age of the stored blood. Our laboratory and others have reported that pentoxifylline (PTX), a nonspecific phosphodiesterase inhibitor, decreases neutrophil activation. We hypothesized that adding PTX to PRBCs would attenuate blood transfusion-induced neutrophil activation.

STUDY DESIGN

Peripheral blood was obtained from healthy human volunteers. Oxidative burst, CD11b, and CD35 expression were measured by flow cytometry using a whole blood preparation. Whole blood was incubated with N-formyl-methionyl-leucyl-phenylalanine (fMLP) (1 microM) alone and 42-day-old PRBC supernatant + fMLP with or without PTX (2 mmol/L).

RESULTS

N-formyl-methionyl-leucyl-phenylalanine alone caused a significant increase in neutrophil oxidative burst (100%). The exposure of whole blood to PRBC supernatants + fMLP led to a 1.3-fold increase in neutrophil oxidative burst as compared with fMLP alone, indicating that PRBC supernatants prime neutrophils for oxidative burst by 75%. More importantly, PTX decreased neutrophil oxidative burst by 114% in supernatant + fMLP-stimulated whole blood (p < 0.001). PTX decreased CD11b expression in both fMLP (p < 0.01) and fMLP+supernatant-stimulated whole blood (p < 0.05). Supernatant from PRBCs did not have an additive effect to fMLP alone on CD11b expression. N-formyl-methionyl-leucyl-phenylalanine-induced CD35 expression was downregulated by PTX. The addition of PRBC supernatant did not increase the already upregulated fMLP-induced CD35 expression.

CONCLUSIONS

Our results suggest that adding PTX to PRBC supernatant markedly decreases neutrophil activation. The lack of successful treatment strategies to effectively modulate the inflammatory response after blood transfusion indicates the need for novel therapies. Because the deleterious effects of blood transfusion on end-organ injury and MOF are associated with neutrophil activation, the adjunct use of PTX to blood transfusion may have therapeutic potential.

Role of Hypertonic Saline and Pentoxifylline on Neutrophil Activation and Tumor Necrosis Factor-α Synthesis: A Novel Resuscitation Strategy

BACKGROUND

Hypertonic saline (HS) and pentoxifylline (PTX) have been shown to modulate polymorphonuclear neutrophil (PMN) functions after shock and sepsis. We hypothesized that a combination of HS and PTX (HSPTX) would down-regulate PMN functions and inflammatory mediator synthesis more effectively than each alone, possibly by acting at different steps of the signaling pathways, ultimately leading to an enhanced effect.

METHODS

Whole blood from healthy volunteers was stimulated with lipopolysaccharide (LPS) (100 microg/mL), f-methionyl-leucyl-phenylalanine (1 micromol/L), and phorbol 12-myristate 13-acetate (1 microg/mL). Baseline oxidative burst was measured by flow cytometry. Two different concentrations of NaCl to achieve increases of 10 mmol/L (HS10) and 40 mmol/L (HS40) above isotonicity, simulating increases in sodium levels seen after infusion of 3% HS and 7.5% HS, were used. PTX (2 mmol/L), HS10, HS40, HSPTX10, and HSPTX40 were added to whole blood concomitantly to the activators. PMN CD14 and CD11b expression were measured by flow cytometry and tumor necrosis factor-alpha levels by enzyme-linked immunosorbent assay in LPS-stimulated whole blood.

RESULTS

The combination of PTX with HS10 and with HS40 markedly decreased LPS- (27 +/- 7 and 23 +/- 6 vs. 100; p < 0.01), f-methionyl-leucyl-phenylalanine- (54 +/- 11 and 55 +/- 8 vs. 100; p < 0.05), and phorbol 12-myristate 13-acetate- (30 +/- 4 and 54 +/- 9 vs. 100; p < 0.01 and p < 0.05, respectively) induced PMN oxidative burst. Furthermore, a significant decrease in LPS-induced neutrophil CD11b expression after PTX treatment (79 +/- 5 vs. 100; p < 0.05) and HSPTX40 (68 +/- 7 vs. 100; p < 0.05) was observed. HSPTX10 (7 +/- 0.6; p < 0.001) or HSPTX40 (6 +/- 1.4; p < 0.001) markedly decreased tumor necrosis factor-alpha production to levels similar to those observed with PTX alone (6.5 +/- 0.5; p < 0.001) and significantly lower than HS10 (110 +/- 4.9; p < 0.001) and HS40 alone (83 +/- 1.5; p < 0.001)

CONCLUSION

HSPTX down-regulates neutrophil activation and proinflammatory mediator synthesis more effectively that HS alone. HSPTX may have significant applications as a novel fluid resuscitation strategy in hemorrhagic shock.

Role of adhesion molecule ICAM in the pathogenesis of polymicrobial sepsis

INTRODUCTION

Intercellular adhesion molecule-1 (ICAM-1) is thought to be involved in polymorphonuclear leukocytes (PMNL) recruitment and secondary organ damage in response to infection and inflammation. The precise role of ICAM-1 in disease progression is unknown and remains a topic of controversy. The aim of this study was to investigate the effect of ICAM-1 on histological changes and cytokine synthesis in a murine model of polymicrobial sepsis.

METHODS

Polymicrobial sepsis was induced in experimental animals by caecal ligation and puncture (CLP). A control group was formed using sham laparotomy without CLP. In order to ascertain the role of ICAM-1 in the response, procedures were performed in both ICAM-1 knockout animals (ICAM-1-/-) and in C57BL/6 mice that were not genetically modified (wild type, WT). Clinical response was observed daily, morphological changes occurring in the lung and liver were studied using light microscopy and quantified using a scoring system. Plasma concentrations of various cytokines (TNF-alpha, IL-6, IL-10) were measured via ELISA.

RESULTS

In ICAM-1-/- mice a less severe clinical response to induced sepsis was observed with significantly less weight loss and hypothermia. A significantly lower mortality rate was observed in ICAM-1-/- mice (12.5% vs. WT: 45.5%) and no significant histological changes were apparent in pulmonary or hepatic tissue on light microscopy following CLP. In WT animals however, significant evidence of leukocyte infiltration and interstitial thickening in pulmonary tissue was observed. Similarly, hepatic tissue sinusoidal widening and hydropic degeneration was present. In addition, pro- and anti-inflammatory cytokine synthesis in ICAM-1-/- animals was significantly attenuated when compared to WT mice. (ICAM-1-/-: TNF-alpha: 67.7+/-12.1pg/microl; IL-6: 208.9+/-26.7pg/microl; IL-10: 34.6+/-5.8pg/microl; WT: TNF-alpha: 840.7+/-150.2pg/microl; IL-6: 3100.2+/-1052.3 pg/microl; IL-10: 1550.1+/-495.7 pg/microl).

DISCUSSION

This study suggests that ICAM-1 has an important pathophysiological role in the response to polymicrobial sepsis. It would appear that absence of this molecule impairs the ability of PMNL to migrate into organ tissues and reduces consequent secondary organ damage resulting in improved clinical status and overall survival. Further investigation into the effectiveness of ICAM-1 modulation in the treatment of sepsis is warranted.

Nonspecific phosphodiesterase inhibition attenuates liver injury in acute endotoxemia

BACKGROUND

Endotoxemia is accompanied by pro-inflammatory cytokine production, generation of reactive oxygen species, and end-organ injury. Pentoxifylline (PTX), a methylxanthine derivative and phosphodiesterase inhibitor, is known for its anti-inflammatory properties, including down-regulation of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha synthesis. Its effects on liver function and hepatic histology following acute endotoxemia have not been investigated fully. We hypothesized that PTX would preserve liver architecture and function after intravenous lipopolysaccharide (LPS) injection.

METHODS

Anesthetized Sprague-Dawley rats received an i.v. bolus injection of LPS (5 mg/kg), LPS + PTX (25 mg/kg), or saline (sham). Plasma concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), TNF-alpha, IL-6, and nitrite were measured at different time points after LPS injection. Liver injury was graded according to a scoring system in a blinded fashion from 0 (normal) to 4 (severe) for hepatocellular necrosis, hemorrhage, and parenchymal and sinusoidal inflammatory infiltrates. Neutrophil infiltration was measured by counting myeloperoxidase (MPO)-positive stained cells. Nuclear factor (NF)-kappaB p-65 was measured by counting positive stained nuclei of hepatocytes and Kupffer cells (KC). Inducible nitric oxide synthase (iNOS) was evaluated by positively stained KC. Data are presented as mean +/- SEM. Analysis of variance with p < 0.05 was considered statistically significant.

RESULTS

Animals treated with PTX showed a significant reduction in liver injury score and neutrophil infiltration. Treatment with PTX significantly decreased TNF-alpha, IL-6, and the concentrations of AST and ALT when compared to LPS alone. In addition, a significant decrease in NF-kappaB-positive staining in hepatocytes and KC, as well as in KC iNOS immunostaining was observed in PTX-treated animals compared to the LPS group.

CONCLUSIONS

Pentoxifylline downregulates the inflammatory response significantly and decreases liver injury in acute endotoxemia.

Acute Respiratory Distress Syndrome

Acute lung injury is a syndrome diagnosed clinically and is one of the most common causes of respiratory failure seen in the intensive care unit. A consensus definition of this and its more severe form, acute respiratory distress syndrome (ARDS), has allowed for better consistency in determining the epidemiology and facilitates consistent clinical trial design to better find therapies to treat or prevent it. Patients who present with ARDS usually show signs of tachpnea or dyspnea and have underlying conditions that promote inflammatory responses. The pathogenesis involves an inflammatory insult that eventually destroys the pulmonary capillary vasculature as well as alveoli. Pathophysiologically, the patient with ARDS may progress through as many as 3 phases: exudative, proliferative, and fibrotic. Treatment options can be either nonpharmacologic or pharmacologic and are limited. Ventilator strategies such as low-tidal-volume ventilation have improved outcomes in these patients, while corticosteroid use is not as established to provide morbidity or mortality benefit. Other therapies have been investigated with inconclusive or disappointing results for the treatment of this fatal syndrome.

LPS-Stimulated PMN Activation and Proinflammatory Mediator Synthesis is Downregulated by Phosphodiesterase Inhibition: Role of Pentoxifylline

BACKGROUND

Excessive production of reactive oxygen species by PMN is associated with tissue damage during inflammation. LPS interacts with the cell surface receptor CD14, which generates transmembrane signals through Toll-like protein 4 leading to mitogen activated protein kinase (MAPK) p38 activation, cytokine synthesis, PMN beta2-integrin expression and oxidative burst. Phosphodiesterase inhibition decreases proinflammatory cytokine production and tissue injury after LPS challenge. Its effects on PMN function after LPS stimulation, however, have not been fully investigated. We hypothesized that LPS-induced TNF-alpha synthesis and subsequent PMN beta2-integrin expression and oxidative burst are downregulated by concomitant treatment with the non-specific phosphodiesterase inhibitor pentoxifylline (PTX).

METHODS

Whole blood was incubated with HBSS (control), LPS (100 microg/mL), fMLP (1 micromol/L), LPS+PTX (2 mmol/L) and fMLP+PTX for different time intervals at 37C. Oxidative burst, CD14, and CD-11b expression were measured by flow cytometry. Serum TNF-alpha levels were measured by ELISA. In an attempt to localize the site of action of PTX (proximal or distal to PKC) cell surface receptors were bypassed by PMA stimulation (1 microg/mL) and oxidative burst was measured with and without PTX.

RESULTS

Up-regulation of CD14 expression was similar in LPS and LPS+PTX groups. LPS stimulation caused a significant increase in PMN oxidative burst, CD11b expression, and TNF-alpha serum levels. In addition, PMA and fMLP stimulation also caused significant increase in oxidative burst compared with controls. Concomitant addition of PTX to LPS led to a significant decrease in PMN oxidative burst (65%; p < 0.0001), PMN CD11b expression (20%; p = 0.012), and TNF-alpha levels (93%; p < 0.0001). Also, PMA- and fMLP-induced PMN oxidative burst were significantly decreased by PTX [77.5% (p < 0.0001) and 50% (p < 0.01), respectively].

CONCLUSIONS

These results suggest that PTX-inhibition of oxidative burst occurs distal to PKC and may be either due to direct inhibition of NADPH oxidase or inhibition of MAPK phosphorylation, leading to decreased adhesion molecule expression and TNF-alpha synthesis. Its use in clinical scenarios in which PMN are primed may be of clinical relevance.

Pentoxifylline reduces fibrin deposition and prolongs survival in neonatal hyperoxic lung injury

Bronchopulmonary dysplasia is a leading cause of mortality and morbidity in preterm infants despite improved treatment modalities. Pentoxifylline, a phosphodiesterase inhibitor, inhibits multiple processes that lead to neonatal hyperoxic lung injury, including inflammation, coagulation, and edema. Using a preterm rat model, we investigated the effects of pentoxifylline on hyperoxia-induced lung injury and survival. Preterm rat pups were exposed to 100% oxygen and injected subcutaneously with 0.9% saline or 75 mg/kg pentoxifylline twice a day. On day 10, lung tissue was harvested for histology, fibrin deposition, and mRNA expression, and bronchoalveolar lavage fluid was collected for total protein concentration. Pentoxifylline treatment increased mean survival by 3 days (P = 0.0018) and reduced fibrin deposition by 66% (P < 0.001) in lung homogenates compared with untreated hyperoxia-exposed controls. Monocyte chemoattractant protein-1 expression in lung homogenates was decreased, but the expressions of TNF-alpha, IL-6, matrix metalloproteinase-12, tissue factor, and plasminogen activator inhibitor-1 were similar in both groups. Total protein concentration in bronchoalveolar lavage fluid was decreased by 33% (P = 0.029) in the pentoxifylline group. Pentoxifylline treatment attenuates alveolar fibrin deposition and prolongs survival in preterm rat pups with neonatal hyperoxic lung injury, probably by reducing capillary-alveolar protein leakage.

Pentoxifylline for neonatal sepsis

BACKGROUND

Although the overall incidence of neonatal sepsis has declined over the past decade, mortality remains high in the pre term infant. The high level of mortality and morbidity from sepsis despite the use of potent anti-microbial agents, and the global emergence of antibiotic resistance, have led to the search for new modalities to boost new born host defences. Pentoxifylline, a xanthine derivative and a phosphodiesterase inhibitor, has been shown to possess a broad spectrum of activity modulating inflammation.

OBJECTIVES

The primary objective was to assess the effect on mortality and the safety of intravenous pentoxifylline as an adjunct to antibiotic therapy in neonates with suspected or confirmed sepsis.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2002), MEDLINE, EMBASE and CINAHL were searched in October 2002 and again in March 2003. Science Citation Index for articles referencing Lauterbach 1996 and Lauterbach 1999 was searched as well as proceedings of the Pediatric Academic Societies which were published in Pediatric Research from 1980. Doctoral dissertations and theses were searched from 1980. The reference lists of identified RCTs, and personal files were searched. No language restriction was applied.

SELECTION CRITERIA

Studies were included if they were randomised or quasi-randomised trials, assessing the efficacy of pentoxifylline compared to placebo or no intervention as an adjunct to antibiotic therapy of suspected or confirmed sepsis in newborn infants less than 28 days old. Eligible trials were required to report treatment effects on at least one of the following outcomes: all cause mortality during initial hospital stay, neurological development at two years of age or later, length of hospital stay, duration of ventilation via endotracheal intubation, chronic lung disease in survivors, periventricular leukomalacia, necrotising enterocolitis, or adverse events.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted information for the outcomes of interest. Any differences were resolved by mutual discussion. Typical Relative Risk (RR) and Risk Difference (RD) with 95% confidence intervals (CI) using fixed effects model are reported for dichotomous outcomes. NNT was calculated for outcomes for which there was a statistically significant reduction in RD.

MAIN RESULTS

Two RCTs enrolled a total of 140 preterm (< 36 weeks) neonates with suspected late onset (> 7 days) sepsis to evaluate the effect of pentoxifylline on neonatal outcomes. However, the two studies reported outcomes of only the 107 randomised patients with confirmed sepsis. The results showed a reduction in 'all cause mortality during hospital stay' following pentoxifylline treatment [typical RR 0.14 (95% CI 0.03, 0.76), RD -0.16 (95% CI -0.27, - 0.04), NNT 6 (95% CI 4, 25)]. No adverse effects due to pentoxifylline were observed in the two included trials. No other outcomes of interest were reported.

REVIEWER'S CONCLUSIONS

Current evidence suggests that the use of pentoxifylline as an adjunct to antibiotics in neonatal sepsis reduces mortality without any adverse effects. But the number of neonates studied is small and considerable methodological weaknesses exist in the included trials. Hence these results should be interpreted with caution. Researchers are encouraged to undertake large well-designed trials to confirm or refute the effectiveness of pentoxifylline to reduce mortality and adverse outcomes in neonates with suspected or confirmed neonatal sepsis. Researchers might also compare pentoxifylline with other adjuncts to antibiotics which modulate inflammation (e.g. intravenous immunoglobulins, haematopoetic colony stimulating factors among others) in reducing mortality and morbidity due to neonatal sepsis.