Effects of pentoxifylline on circulating cytokine concentrations and hemodynamics in patients with septic shock: results from a double-blind, randomized, placebo-controlled study

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.

Proinflammatory cytokines levels in sepsis and healthy volunteers, and tumor necrosis factor-alpha associated sepsis mortality: A systematic review and meta-analysis

BACKGROUND

Sepsis is a global health challenge associated with significant morbidity and mortality. Detrimental sepsis effects are attributed to excessive inflammation or a "cytokine storm." However, anti-inflammation therapies have failed to lower sepsis mortality. We aim to characterize levels of key inflammatory cytokines in patients with sepsis and compare levels with those in healthy individuals and relate tumor necrosis factor (TNF) α levels to patient characteristics and outcomes.

METHODS

We performed a systematic review and meta-analysis. Medline, Embase, Cochrane Library, and Web of Science Core Collection databases were searched between 1985 and May 2020. Analysis was restricted to studies in English. We included randomized controlled trials (RCTs), controlled trials, cohort studies, case series, and cross-sectional studies that reported mean levels of cytokines in the circulation thought to be relevant for sepsis pathogenesis. We also evaluated concentrations of these cytokines in healthy individuals. The Quality in Prognosis Studies tool was used to assess the methodological quality of included studies. We extracted summary data from published reports. Data analyses were performed using a random-effects model to estimate pooled odds ratios (OR) with 95% confidence intervals for cytokine levels and mortality. This systematic review is registered in PROSPERO (CRD42020179800).

FINDINGS

We identified 3654 records, and 104 studies were included with a total of 3250 participants. The pooled estimated mean TNFα concentration in sepsis patients was 58.4 pg/ml (95% Confidence Interval or CI 39.8-85.8 pg/ml), and in healthy individuals was 5.5 pg/ml (95% CI 3.8-8.0 pg/ml). Pooled estimate means for IL-1β and IFN-γ in sepsis patients were 21.8 pg/ml and 63.3 pg/ml, respectively. Elevated TNFα concentrations associated with increased 28-day sepsis mortality (p = 0.001). In subgroup analyses, we did not detect an association between TNFα levels and sepsis source, sepsis severity, or sequential organ failure assessment (SOFA) score. A TNF-α cutoff level ≥14.7 pg/ml separated sepsis patients from healthy individuals with a sensitivity of 82.6%, a specificity of 91.7%, and a likelihood ratio of 9.9.

INTERPRETATION

Sepsis mean TNFα concentration is increased approximately 10-fold compared to mean concentration in healthy individuals, and TNFα associated with sepsis mortality but not sepsis severity. The concept that elevated cytokines cause sepsis should be revisited in the context of these data.

FUNDING

None.

Anti-TNF-α Compounds as a Treatment for Depression

Millions of people around the world suffer from psychiatric illnesses, causing unbearable burden and immense distress to patients and their families. Accumulating evidence suggests that inflammation may contribute to the pathophysiology of psychiatric disorders such as major depression and bipolar disorder. Copious studies have consistently shown that patients with mood disorders have increased levels of plasma tumor necrosis factor (TNF)-α. Given these findings, selective anti-TNF-α compounds were tested as a potential therapeutic strategy for mood disorders. This mini-review summarizes the results of studies that examined the mood-modulating effects of anti-TNF-α drugs.

Novel therapeutic targets in mood disorders: Pentoxifylline (PTX) as a candidate treatment

Numerous pharmacological treatments for mood disorders are currently available; however, rates of treatment resistance, relapse and recurrence remain high. Therefore, novel treatments acting outside of the conventionally targeted monoamine system are urgently needed to improve patient outcomes. Emerging and converging evidence suggests that immune dysfunction, oxidative stress, impaired cerebral blood flow (CBF) and decreased neurotrophic factors all contribute to mood disorder pathophysiology and are therefore treatment targets of interest. Pentoxifylline (PTX) is a phosphodiesterase inhibitor with potent anti-inflammatory and antioxidant effects, with additional pleiotropic effects that lead to improved CBF and increases in brain derived neurotrophic factor (BDNF) levels. The direct effect of non-specific phosphodiesterase inhibition may also improve alertness and cognitive function through enhancing second messenger systems. Replicated preclinical studies have demonstrated antidepressant-like effects in animal models. Small preliminary clinical trials have demonstrated promising results for antidepressant and procognitive effects, however, have yet to be replicated in larger mood disorder samples. Only one randomized clinical trial (RCT) specifically assessed the effects of adjunctive PTX in major depressive disorder (MDD), showing clinically and statistically significant antidepressant effects compared to placebo. No studies have assessed PTX in bipolar disorder (BD), where inflammation and altered CBF have also been strongly implicated. Taken together, PTX presents as a promising pleiotropic agent with several potential novel mechanisms of action meriting further evaluation in clinical trials to evaluate target engagement, antidepressant, procognitive and mood stabilizing effects.

Comparison of Antithrombin III and Pentoxifylline Treatments in Gram Negative Sepsis Patients Developing Disseminated Intravascular Coagulation

Objective:

The aim of this study was to evaluate the effects of antithrombin III (AT III) and pentoxifylline treatments on the gram negative septic patients with disseminated intravascular coagulation (DIC).

Method:

For six days after plasma AT III activity dropped lower than 80% in Gram-patients who developed DIC were treated with AT III (90-120 IU/kg/day in 6 hours) or pentoxifylline (1.5 mg/kg/h in 6 hours) Fibrinogen, FDP, D-dimer, complete blood count, AT III activity, and DIC scores were calculated and recorded.

Results:

The coagulation tests, AT III activity and FDP started to improve from the second day of treatment with both treatments (p<0.05). D-Dimer started to decrease on the second day of treatment with pentoxifylline (p<0.001) and fourth day of AT III treatment (p<0.05). Fibrinogen levels decreased on the second day of pentoxifylline treatment (p<0.05) and on the last day of AT III treatment (p<0.001). DIC scores started to decrease on the last day of treatment with AT III treatment (p<0.001) and on the third day of treatment with pentoxifylline (p<0.05).

Conclusion:

Both ATIII and pentoxifylline treatments had positive effects on fibrinogen, FDP, D-Dimer, AT III activity and DIC scores in patients with Gram-negative sepsis who developed DIC.

Protection against lethal polymicrobial sepsis by CNI-1493, an inhibitor of pro-inflammatory cytokine synthesis

Polymicrobial sepsis caused by cecal ligation and puncture (CLP) in mice produces the inflammatory and pathological sequelae of lung neutrophil infiltration, adult respiratory distress syndrome (ARDS) and death. These sequelae are dependent upon the synergistic interaction between several inflammatory mediators, including tumor necrosis factor (TNF), interleukin 1 (IL-1 ), and nitric oxide (NO). The overlapping spectrum of multiple mediator toxicity has hampered efforts to develop therapies for sepsis based on selective inhibition of a single mediator. Therefore, we tested the hypothesis that inhibition of multiple pro-inflammatory mediators would abrogate lethality. Our results show that administration of a tetravalent guanylhydrazone compound (CNI-1493) protected mice against 10 day mortality in CLP. Evidence of suppression of the cytokine cascade was given by decreased serum levels of TNF and IL-6 in CNI-1493 treated animals (TNF reduced 60% as compared to controls; IL-6 reduced 90% compared to controls; P < 0.05), and decreased levels of the acute-phase protein serum amyloid A response measured 24 h after CLP. Serum nitrites/nitrates, which give an index of NO production, were also significantly reduced (50%). Protection against CLP induced lung damage was observed as attenuation of edema and alveolar neutrophil infiltration, suppression of pulmonary TNF levels, and reduction of TUNEL-positive staining in lung. We conclude that CNI-1493 effectively inhibits the synthesis of multiple pro-inflammatory mediators and protects against death during polymicrobial sepsis.

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.

Pentoxifylline and its applications in dermatology

Pentoxifylline is a methyl-xanthine derivative with many anti inflammatory effects. Pentoxifylline has been found to be effective for many dermatological as well as non-dermatological conditions. It has been used both as primary drug as well as adjuvant and is a safe and relatively cost-effective alternative drug. In this article, we review the literature and highlight various important aspects of pentoxifylline.

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.

Novel treatments for NEC: keeping IBD in mind

Necrotizing enterocolitis (NEC) is an inflammatory intestinal disease of premature newborns, thought to result in part from overactivity of the innate immune system. NEC has been well-studied from the perspective of prevention; however, after the disease onset, there are limited treatment options to control its progression. This review discusses four potential therapies that target the overactive immune response in NEC: pentoxifylline, platelet activating factor modulators, glucocorticoids, and vasoactive substances. In addition, given the similar pathogenesis of NEC and inflammatory bowel disease (IBD), we propose that IBD therapies could provide promising leads for novel strategies with which to treat NEC.

Surfactant therapy for acute lung injury and acute respiratory distress syndrome

This article examines exogenous lung surfactant replacement therapy and its usefulness in mitigating clinical acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). Surfactant therapy is beneficial in term infants with pneumonia and meconium aspiration lung injury, and in children up to age 21 years with direct pulmonary forms of ALI/ARDS. However, extension of exogenous surfactant therapy to adults with respiratory failure and clinical ALI/ARDS remains a challenge. This article reviews clinical studies of surfactant therapy in pediatric and adult patients with ALI/ARDS, focusing on its potential advantages in patients with direct pulmonary forms of these syndromes.

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.

Neonatal sepsis and neutrophil insufficiencies

Sepsis has continuously been a leading cause of neonatal morbidity and mortality despite current advances in chemotherapy and patient intensive care facilities. Neonates are at high risk for developing bacterial infections due to quantitative and qualitative insufficiencies of innate immunity, particularly granulocyte lineage development and response to infection. Although antibiotics remain the mainstay of treatment, adjuvant therapies enhancing immune function have shown promise in treating sepsis in neonates. This article reviews current strategies for the clinical management of neonatal sepsis and analyzes mechanisms underlying insufficiencies of neutrophil defense in neonates with emphasis on new directions for adjuvant therapy development.

Immunomodulatory properties of pentoxifylline are mediated via adenosine-dependent pathways

The phosphodiesterase inhibitor pentoxifylline (PTX) exerts multiple beneficial immunomodulatory effects in states of hyperinflammation. However, the exact mechanism of action still remains elusive, and the clinical effects of PTX cannot be reliably predicted. In immune cells, the G protein-coupled adenosine A2A receptor (A2AR) exerts strong anti-inflammatory effects. As PTX amplifies signaling pathways downstream of Gs protein-coupled receptors, the A2AR-signaling pathway might be involved in the mediation of immune-suppressive effects of PTX. Here, we investigated this assumption in LPS-stimulated human polymorphonuclear (PMN) leukocytes and in anti-CD3/CD28-stimulated human T cells. In stimulated PMN leukocytes, PTX treatment led to a 4.5-fold decrease of the 50% inhibitory concentrations of adenosine on the H2O2 production; i.e., for adenosine plus PTX (in clinically relevant concentrations), an overadditive increase of inhibitory effects from less than 20% (estimated for each) to 56% (+/-5%) was found. In T cells, adenosine plus PTX revealed similar synergistic inhibitory effects on proinflammatory cytokine production. Inhibition of interferon gamma and TNF-alpha production increased from 7% (+/-1%) and 31% (+/-6%) (PTX alone) to 49% (+/-2%) and 69% (+/-6%), respectively. In T cells and PMN leukocytes, mRNA transcription of the A2AR was significantly increased upon stimulation, which was not influenced by PTX. In human PMN leukocytes and T cells, clinically relevant anti-inflammatory effects of PTX can be achieved only in the presence of sufficient adenosine concentrations. Sufficient adenosine levels might be a prerequisite for the accessibility of sepsis patients to treatment with PTX.

Pharmacokinetic modelling of pentoxifylline and lisofylline after oral and intravenous administration in mice

The aim of this study was to develop pharmacokinetic models for pentoxifylline (PTX) and the R(-)-enantiomer of the PTX metabolite 1, lisofylline (LSF), in order to identify some factors influencing the absorption of these compounds from the intestines and to clarify mechanisms involved in their non-linear pharmacokinetics. Serum samples were collected after oral and intravenous administration of PTX and LSF to male CD-1 mice at two different doses. In addition, both compounds under investigation were coadministered with a modulator of drug transporters, verapamil, and an inhibitor of cytochrome P450 (CYP) 3A4, ketoconazole. Pharmacokinetic analysis revealed that a one-compartment model with Michaelis-Menten type absorption and elimination best described the pharmacokinetics of PTX, whereas the LSF concentration-time data were adequately fitted to a two-compartment model with a first-order absorption and Michaelis-Menten type elimination process. Both coadministered compounds significantly decreased the area under the concentration-time curve from 0 to 60 min calculated for PTX and increased the value of this parameter for LSF. The results of this study indirectly suggest that saturation of drug transport across intestinal cells and elimination from the central compartment may be responsible for the non-linear pharmacokinetics of PTX, whereas in the case of LSF, the dose dependency in the pharmacokinetics is solely related to the elimination from the central compartment. It seems that the observed changes in PTX and LSF concentrations after coadministration with verapamil and ketoconazole may be clinically significant, especially after chronic treatment, however further studies are necessary to assess the importance of these interactions in humans.

Protein array technology to investigate cytokine production by monocytes from patients with advanced alcoholic cirrhosis: An ex vivo pilot study

AIM

In patients with advanced cirrhosis, little is known about the ability of peripheral blood monocytes to spontaneously produce signaling proteins such as cytokines. The aim of this ex vivo study was to evaluate cytokine production under baseline conditions and after stimulation by lipopolysaccharide (LPS), a toll-like receptor (TLR) agonist.

METHODS

Peripheral blood monocytes were isolated from patients with advanced alcoholic cirrhosis (without ongoing bacterial infections) and normal subjects. Cells were left unstimulated or were stimulated with LPS. The abundance of 24 cytokines was measured using a filter-based, arrayed sandwich enzyme-linked immunosorbent assay (ELISA) in the supernatant of cultured monocytes.

RESULTS

Cirrhotic monocytes spontaneously produced six proteins (TNF-alpha, IL-6, IL-8, MCP-1, RANTES and Gro), whereas normal monocytes produced only small amounts of IL-8 and RANTES. Analyses with the online gene set analysis toolkit WebGestalt (http://bioinfo.vanderbilt.edu/webgestalt) found enrichment for the six proteins in the human gene ontology subcategory (http://www.geneontology.org), Kyoto Encyclopedia of Genes and Genome pathways (http://www.genome.ad.jp/kegg/) and BioCarta pathways (http://www.biocarta.com/genes/index.asp) consistent with a proinflammatory phenotype of cirrhotic monocytes resulting from activated TLR signaling. Interestingly, LPS-elicited TLR engagement further increased the production of the six proteins and did not induce the secretion of any others, in particular the anti-inflammatory cytokine IL-10. LPS-stimulated normal monocytes produced TNF-alpha, IL-6, IL-8, MCP-1, RANTES, Gro and IL-10.

CONCLUSION

In patients with advanced cirrhosis, peripheral blood monocytes spontaneously produce proinflammatory cytokines, presumably in response to unrestricted TLR signaling.

The INIS Study. International Neonatal Immunotherapy Study: non-specific intravenous immunoglobulin therapy for suspected or proven neonatal sepsis: an international, placebo controlled, multicentre randomised trial

BACKGROUND

Sepsis is an important cause of neonatal death and perinatal brain damage, particularly in preterm infants. While effective antibiotic treatment is essential treatment for sepsis, resistance to antibiotics is increasing. Adjuvant therapies, such as intravenous immunoglobulin, therefore offer an important additional strategy. Three Cochrane systematic reviews of randomised controlled trials in nearly 6,000 patients suggest that non-specific, polyclonal intravenous immunoglobulin is safe and reduces sepsis by about 15% when used as prophylaxis but does not reduce mortality in this situation. When intravenous immunoglobulin is used in the acute treatment of neonatal sepsis, however, there is a suggestion that it may reduce mortality by 45%. However, the existing trials of treatment were small and lacked long-term follow-up data.This study will assess reliably whether treatment of neonatal sepsis with intravenous immunoglobulin reduces mortality and adverse neuro-developmental outcome.

METHODS AND DESIGN

A randomised, placebo controlled, double blind trial. Babies with suspected or proven neonatal sepsis will be randomised to receive intravenous immunoglobulin therapy or placebo.

ELIGIBILITY CRITERIA

Babies must be receiving antibiotics and have proven or suspected serious infection AND have at least one of the following: birthweight less than 1500 g OR evidence of infection in blood culture, cerebrospinal fluid or usually sterile body fluid OR be receiving respiratory support via an endotracheal tube AND there is substantial uncertainty that intravenous immunoglobulin is indicated.

EXCLUSION CRITERIA

Babies are excluded if intravenous immunoglobulin has already been given OR intravenous immunoglobulin is thought to be needed OR contra-indicated. Trial treatment: Babies will be given either 10 ml/kg of intravenous immunoglobulin or identical placebo solution over 4-6 hours, repeated 48 hours later.

PRIMARY OUTCOME

Mortality or major disability at two years, corrected for gestational age.

DATA COLLECTION

Data will be collected at discharge from hospital and at 2 years of age (corrected for gestation) using a parental questionnaire and a health status questionnaire completed during a face-to-face follow-up appointment with the child's paediatrician.

TRIAL REGISTRATION

Current Controlled Trials ISCRTN94984750.

Oxidative stress and "senescent" fibroblasts in non-healing wounds as potential therapeutic targets

In chronic wounds, fibroblast dysfunctions, such as increased apoptosis, premature senescence, senescence-like phenotype, or poor growth response in the absence of senescence markers, have been reported. Some of these differential dysfunctions may be secondary to differences in patient age or sex, ulcer size or duration, edge versus base sampling, or culture technique. Nevertheless, the entire spectrum of fibroblast dysfunction may exist and be secondary to, or a response to, different amounts of oxidative stress.

The effect of pentoxifylline on the pulmonary response to high tidal volume ventilation in rats

BACKGROUND

Volume-induced lung injury is associated with lung inflammation. Pentoxifylline inhibits cytokine release and modulates neutrophil function.

OBJECTIVE

To evaluate the efficacy of pentoxifylline in the attenuation of lung inflammation induced by high tidal volume ventilation.

DESIGN

Adult rats were randomly assigned to receive saline as placebo or pentoxifylline (100mg/kg over 30 min, followed by 50mg/kg/h) before and during 4h of high tidal volume ventilation (20 ml/kg). Bronchoalveolar fluid inflammatory mediators were measured at baseline and after 4h of ventilation. Lung tissue myeloperoxidase activity and wet/dry lung weight were assessed upon completion of the study.

RESULTS

Bronchoalveolar tumor necrosis factor-alpha (pentoxifylline vs. placebo; 192+/-61 vs. 543+/-99 pg/ml; p<0.007) and thromboxane B(2) (262+/-26 vs. 418+/-49 pg/ml; p<0.02) concentrations, lung myeloperoxidase activity (0.5+/-0.1 vs. 1.2+/-0.2U/mg; p<0.003) and wet/dry weight (6.1+/-0.2 vs. 7.1+/-0.3; p<0.01) were all significantly lower in the pentoxifylline-treated group.

CONCLUSION

Pentoxifylline was effective in reducing inflammatory lung injury associated with high tidal volume ventilation.

Understanding the inflammatory cytokine response in pneumonia and sepsis: results of the Genetic and Inflammatory Markers of Sepsis (GenIMS) Study

BACKGROUND

Severe sepsis is common and frequently fatal, and community-acquired pneumonia (CAP) is the leading cause. Although severe sepsis is often attributed to uncontrolled and unbalanced inflammation, evidence from humans with infection syndromes across the breadth of disease is lacking. In this study we describe the systemic cytokine response to pneumonia and determine if specific patterns, including the balance of proinflammatory and anti-inflammatory markers, are associated with severe sepsis and death.

METHODS

This is a cohort study of 1886 subjects hospitalized with CAP through the emergency departments in 28 US academic and community hospitals. We defined severe sepsis as CAP complicated by new-onset organ dysfunction, following international consensus conference criteria. We measured plasma tumor necrosis factor, IL-6 (interleukin 6), and IL-10 levels daily for the first week and weekly thereafter. Our main outcome measures were severe sepsis and 90-day mortality.

RESULTS

A total of 583 patients developed severe sepsis (31%), of whom 149 died (26%). Systemic cytokine level elevation occurred in 82% of all subjects with CAP. Mean cytokine concentrations were highest at presentation, declined rapidly over the first few days, but remained elevated throughout the first week, beyond resolution of clinical signs of infection. Cytokine levels were highest in fatal severe sepsis and lowest in CAP with no severe sepsis. Unbalanced (high/low) cytokine patterns were unusual (4.6%) and not associated with decreased survival. Highest risk of death was with combined high levels of the proinflammatory IL-6 and anti-inflammatory IL-10 cytokine activity (hazard ratio, 20.5; 95% confidence interval, 10.8-39.0) (P<.001).

CONCLUSIONS

The circulating cytokine response to pneumonia is heterogeneous and continues for more than a week after presentation, with considerable overlap between those who do and do not develop severe sepsis. Unbalanced activation is uncommon, and mortality is highest when both proinflammatory and anti-inflammatory cytokine levels are high.

Interconversion and tissue distribution of pentoxifylline and lisofylline in mice

The aim of this study was to assess the interconversion pharmacokinetics and tissue distribution of pentoxifylline and the active (R)-enantiomer of its metabolite M1, lisofylline in male CD-1 mice. Both compounds were administered intravenously at a dose of 50 mg/kg on two separate occasions. Serum and tissues were collected at different time points following drug administration. In addition, the (S)-enantiomer of M1 was administered to a group of mice and serum samples were obtained. Analyte concentrations were measured by chiral HPLC. All serum concentration versus time data were fitted simultaneously to a pharmacokinetic model incorporating interconversion processes of parent drug and metabolites. The estimated conversion clearance of (-)-(R)-M1 to pentoxifylline (CL21) was six times greater than that for the reverse process (CL12). The interconversion of pentoxifylline and (+)-(S)-M1 was faster as reflected by the values of conversion clearances CL13 and CL31 which were approximately 16 and 7 times greater in comparison with the corresponding clearances for the interconversion of pentoxifylline and (-)-(R)-M1. When fitting pharmacokinetic data of both parent compounds to a one-compartment model, the values of elimination clearances assessed were close to those obtained on the basis of the interconversion model. After administration of pentoxifylline, tissue-to-serum AUC ratios ranged from 0.1 for liver and lungs to 0.32 for brain tissue. Serum levels of its metabolite, (-)-(R)-M1 were very low, whereas its tissue levels exceeded serum concentrations. The highest value of metabolite-to-parent AUC ratio (4.98) was observed in lungs. When (-)-(R)-M1 was given as a parent drug, tissue-to-serum AUC ratios in liver, kidney, and lungs were very close and ranged from 0.64 to 0.72. At the same time, levels of its metabolite, pentoxifylline were relatively low both in serum and all tissues studied. In consequence, metabolite-to-parent AUC ratios did not exceed the value of 0.27. In conclusion, reversible metabolism plays a modest role in the disposition of pentoxifylline and (-)-(R)-M1. It seems that pentoxifylline has less favourable pharmacokinetic properties than (-)-(R)-M1 due to lower concentrations attained in target organs. High levels of (-)-(R)-M1 observed after pentoxifylline administration in certain tissues such as liver or lungs suggest that pentoxifylline may constitute an effective prodrug for (-)-(R)-M1 in these organs.

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.

Protective Effect of Pentoxifylline on Volume-Induced Lung Injury in Newborn Piglets

To evaluate the efficacy of pentoxifylline (PTXF) in the attenuation of lung inflammation during volume-induced lung injury (VILI) in newborn piglets, 17 newborn piglets were mechanically ventilated with a large tidal volume (50 ml/kg) for a period of 8 h. They were randomly assigned to a placebo (PL, n = 9) or a treatment group (PTXF, n = 8) that received PTXF (20 mg/kg as a bolus, followed by a continuous infusion of 5 mg/kg/h). Hemodynamics, lung mechanics and arterial blood gases were measured during the 8 h of study. Serum and tracheoalveolar fluid (TAF) platelet-activating factor (PAF) and thromboxane (TXB(2)) levels were obtained at baseline and at 8 h, while lung tissue myeloperoxidase (MPO) and wet to dry weight were assessed after the completion of the study. In the PL group, a marked increase in TAF PAF and TXB(2) levels was observed only in TAF, suggesting that the inflammatory process was localized within the lungs. A significant decrease in lung tissue MPO activity (p < 0.005) and lung wet to dry weight ratio (p < 0.04) was observed in the PTXF group. There were no differences in hemodynamics, arterial blood gases or lung mechanics measurements between groups. A significant reduction in pulmonary inflammatory response was observed during VILI in the PTXF pretreated animals. These results suggest that PTXF may be effective in modulating lung inflammation associated with mechanical ventilation in neonates.

Extrinsic allergic alveolitis: inhibitory effects of pentoxifylline on cytokine production by alveolar macrophages

BACKGROUND

Pentoxifylline is a well-established drug with hemorheologic properties. Various evidence suggests an additional therapeutic potential in regard to inflammation and immunomodulation. Extrinsic allergic alveolitis (EAA) is a granulomatous disease that is driven by T-cell and alveolar macrophage (AM)-derived cytokines.

OBJECTIVE

To investigate the effects of pentoxifylline on the production of tumor necrosis factor (TNF) alpha, interleukin (IL) 1beta, IL-6, IL-8, IL-10, and the soluble TNF receptors (sTNFR1 and sTNFR2) from AMs in EAA compared with dexamethasone.

METHODS

The AMs from 9 patients with EAA were cultured for 24 hours with RPMI medium alone or lipopolysaccharide (LPS) (100 ng/mL) and with pentoxifylline at concentrations of 0.01, 0.1, and 1 mmol/L or 0.1-mmol/L dexamethasone. Cytokines in the culture supernatants were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Pentoxifylline induced a dose-dependent suppression of spontaneous TNF-alpha and IL-10 release from AMs in EAA. The spontaneous production of other cytokines was unaffected by pentoxifylline at all tested concentrations. Dexamethasone inhibited significantly only the spontaneous release of TNF-alpha. Pentoxifylline and dexamethasone also inhibited the LPS-stimulated production of all cytokines except IL-1beta and sTNFR1.

CONCLUSION

Our results may be the basis for clinical trials to evaluate the role of pentoxifylline as an immunotherapeutic agent in the treatment of EAA.

Pentoxyfylline in and prevention and treatment of chronic lung disease

The anti-inflammatory effects of pentoxfylline are associated with a number of clinical benefits. These include reduction in mortality in patients who have undergone bone marrow transplants or suffer peritonitis. In infants with sepsis, a reduction in mortality has also been associated with pentoxyfylline administration. The anti-inflammatory effects of pentoxyfylline, as well as its bronchodilator, diuretic and respiratory muscle stimulant effects suggest it may have a useful role in BPD. Interim analysis of a prophylactic trial suggests pentoxyfylline may reduce treatment requirements after the neonatal period and that, in established BPD, pentoxyfylline and dexamethasone may be of similar efficacy.

Inhibition of cytokine release from alveolar macrophages in pulmonary sarcoidosis by pentoxifylline: comparison with dexamethasone

STUDY OBJECTIVES

Pentoxifylline (POF) has been shown to suppress the cytokine production from lipopolysaccharide (LPS)-stimulated monocytes/alveolar macrophages (AMs). Sarcoidosis is a granulomatous disease that is driven by the action of tumor necrosis factor (TNF)-alpha and other proinflammatory cytokines. In this study, we aimed to investigate the effects of POF on the production of TNF-alpha, interleukin (IL)-1 beta, IL-6, IL-8, IL-10, and the soluble TNF receptors (sTNFRs) 1 and 2 from AMs in sarcoidosis, and we also compared them with those of dexamethasone (DEX).

METHODS

AMs from 14 patients with sarcoidosis were cultured for 24 h with RPMI medium alone or with LPS (100 ng/mL), and with POF at concentrations of 0.01, 0.1, and 1 mmol/L, or with 0.1 mmol/L DEX. Cytokines in the culture supernatants were analyzed by enzyme-linked immunosorbent assay.

RESULTS

The results showed that POF induced a dose-dependent suppression of the spontaneous TNF-alpha release from AMs in sarcoidosis (p < 0.001), and that the spontaneous release of the other cytokines was unaffected by POF at all tested concentrations, but a trend for the inhibition of IL-10 production was found (p = 0.092). DEX inhibited the spontaneous release of TNF-alpha (p < 0.001), sTNFR2 (p < 0.05), IL-1 beta (p < 0.05), and IL-10 (p < 0.01). POF also suppressed the LPS-stimulated production of these cytokines except for that of sTNFR1. Similar to POF, DEX inhibited the LPS-stimulated production of these cytokines, but not that of sTNFR1 and IL-1 beta.

CONCLUSIONS

Compared with DEX, POF may improve therapeutic regimens in patients with sarcoidosis either by sparing or by replacing corticosteroids. However, the precise clinical value of POF in the treatment of sarcoidosis and other lung diseases will have to be determined in further clinical trials.

Pentoxifyllin attenuates the systemic inflammatory response induced during isolated limb perfusion with recombinant human tumor necrosis factor-alpha and melphalan

BACKGROUND

Isolated limb perfusion (ILP) with recombinant human tumor necrosis factor-alpha (rhTNF-alpha) and melphalan harbors the risk of septic shock-like syndrome. Pentoxifyllin (PTX) produced a beneficial effect on cytokine response and survival in animal experiments of septic shock, and we were interested to explore its effect during TNF-ILP in humans.

METHODS

Eighteen consecutive patients underwent TNF-ILP and received PTX (30 mg/kg/day), whereas another 13 consecutive patients did not. PTX was given systemically after the limb extracorporeal circulation was started. Cardiac index, systemic vascular resistance (SVR), and pulmonary vascular resistance were recorded via a Swan-Ganz catheter. Blood levels of TNF-alpha, interleukin-6, procalcitonin, and lipopolysaccharide-binding protein were determined before, during, and after ILP.

RESULTS

After reperfusion, systemic levels of TNF-alpha were significantly less increased in the PTX group (peak, 2.8 vs. 1.3 ng/mL; P <.05), as were interleukin-6 values (peak, 68 vs. 22 pg/mL; P <.02) and lipopolysaccharide-binding protein plasma levels (peak, 215 vs. 105 micro g/mL; P <.03). Differences in cardiac index, SVR, and mean arterial blood pressure were not significantly different. Norepinephrine or dobutamine to maintain SVR was less required in the PTX group.

CONCLUSIONS

PTX attenuates systemic cytokine production and influences components of the systemic inflammatory response after TNF-ILP. PTX may play a beneficial role in the management of septic shock-like syndrome, particularly in patients with leakage from the ILP circuit.

Novel strategies for the treatment of sepsis

The history of therapeutic interventions in clinical trials for sepsis has been referred to as the "graveyard for pharmaceutical companies." That is now set to change, as research provides hope for new approaches that will be therapeutically effective in humans with sepsis.

Anti-inflammatory strategies for the treatment of sepsis

Sepsis leads to an overwhelming inflammatory response of the host and is usually accompanied by well-known clinical symptoms (fever, tachycardia, leukocytosis, and so on) and the accompanying systemic inflammatory response syndrome (SIRS). Accordingly, most efforts to develop treatment strategies for sepsis have focused on those designed to counteract overactivation of the inflammatory system. Despite intensive research into identifying targets in sepsis, most of the resulting clinical trials have been based on experimental data and have resulted in no beneficial effects (i.e., survival). Recombinant activated protein C (APC) represents the first treatment that has led to restricted approval for use in sepsis in the USA and worldwide. This article reviews approaches to anti-inflammatory treatment in sepsis and provides an outlook into ongoing clinical trials as well as new treatments that have not yet been evaluated in the clinical setting.

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.

Pentoxifylline acutely reduces protein catabolism in chronically uremic patients

BACKGROUND

We investigated the ability of pentoxifylline, a drug with hemorheological actions known to block tumor necrosis factor-alpha (TNF-alpha) release, to modulate whole-body protein kinetics in undialyzed patients with chronic uremia.

METHODS

Leucine rate of appearance (Ra) from proteolysis and leucine oxidation, a marker of net protein loss, were determined by infusing l-[1-13C]leucine and using the reciprocal pool model for calculations.

RESULTS

Intravenous infusion of pentoxifylline in the postabsorptive state (1 mg/kg within 3 hours) decreased the intracellular leucine Ra from proteolysis by -16% +/- 4% versus -3% +/- 2% of saline (P = 0.02) and leucine oxidation by -16% +/- 4% versus +4% +/- 2% of saline (P = 0.003). Combined infusions of pentoxifylline and a balanced amino acid mixture (0.2 mg/kg/min) decreased whole-body proteolysis by -53% +/- 7% versus -26% +/- 6% of amino acid infusion alone (P = 0.02). Circulating levels of TNF-alpha and TNF-alpha soluble receptors (sTNF-Rs) were elevated (P < 0.001) in patients compared with healthy controls. Pentoxifylline infusion did not significantly affect TNF-alpha levels, but decreased sTNF-Rs both in the postabsorptive state and during hyperaminoacidemia.

CONCLUSION

Pentoxifylline acutely decreased whole-body proteolysis in chronically uremic patients. Potential explanations for these pharmacological effects may include downregulation of the TNF-alpha system or other mechanisms related to the rheological action of the drug (eg, increased amino acid or insulin delivery to target cells).

Clinical trials of immunomodulatory therapies in severe sepsis and septic shock

Sepsis remains one of the leading causes of mortality in critically ill patients. Increased insight into the complexities of this disease process has resulted in the targeting of various aspects of the inflammatory response as offering potential therapeutic benefits. There have been encouraging results in the past few years. Some of the tested agents have been shown to improve mortality rates in large randomized controlled trials involving patients with severe sepsis. In this article, we discuss the positive and negative results of trials in this field; some of the possible reasons for the negative results are examined, and directions for the future are suggested.

Randomized, controlled clinical trials in sepsis: has methodological quality improved over time?

OBJECTIVE

To systematically evaluate the methodological quality of randomized clinical trials and to determine whether randomized clinical trials of sepsis improved in methodological quality over time.

DATA SOURCES

Computerized MEDLINE search of articles published in any language from 1966 to 1998 combined with a manual search of bibliographies of published articles and communication with known experts in the field.

STUDY SELECTION

All randomized clinical trials of sepsis, severe sepsis, and septic shock performed in adults and published as full articles.

DATA EXTRACTION

Abstracts of all retrieved records were reviewed and the inclusion criteria were applied. All selected articles were classified into (a) trials designed to detect differences in mortality as the primary end point, or (b) trials focusing on surrogate outcome measures (i.e., physiological or biochemical parameters). All retrieved trials were then graded for methodological quality using an objective grading scheme developed specifically for this study. The data selection and extraction process was carried out independently by two of the authors; any disagreement was resolved by discussion.

DATA SYNTHESIS

Seventy-four randomized clinical trials involving septic patients qualified for inclusion in this study (40 reporting mortality outcomes, 34 reporting other surrogate outcomes). Trials reporting mortality as the primary outcome had significantly higher quality scores compared with trials reporting surrogate outcome measures (29.6 +/- 1.0 vs. 24.3 +/- 0.8, p =.0006). From 1976 to 1998, trial methodology improved significantly over time (an average of 0.36 points per year, p =.021). Mortality outcome trials improved an average of 0.58 points per year (p =.0011) whereas surrogate outcome trials did not demonstrate an improvement in methodological quality over time (p =.249).

CONCLUSION

The methodological limitations identified in this article can help to target further improvement in trial design to enhance the validity of findings from future randomized clinical trials of sepsis.

Kimura's disease with oral ulcers: response to pentoxifylline

We describe a man with Kimura's disease whose presentation included lymphadenopathy and cutaneous nodules, but was most distinctive for painful oral ulcerations. His lesions showed an initially moderate, but ultimately minimal response to monthly triamcinolone injections. With oral pentoxyifylline, he showed resolution of all of his lesions for 14 months. On cessation of his treatment, his disease flared for 3 months. When pentoxyifylline was restarted, his lesions regressed again within 4 weeks. We review the literature on Kimura's disease.

Differential effects of pentoxifylline, a non-specific phosphodiesterase inhibitor, on the production of IL-10, IL-12 p40 and p35 subunits by murine peritoneal macrophages

Pentoxifylline (PTX), a methylxanthine derivative, has been reported to be an effective drug in inhibiting TNF-alpha responses during septic shock. The inhibition of TNF-alpha production seems to be correlated with increased intracellular cAMP levels. PTX also affects the production of other cytokines such as IL-1, IL-6, IL-10, IL-12, and IFN-gamma. However, inhibition, as well as enhancement of cytokine production, has been observed in vitro, depending on the PTX concentration and cell type used.IL-12 is a heterodimeric cytokine that plays an important role in the development of Th1-mediated inflammatory responses. IL-12 along with TNF-alpha and other proinflammatory cytokines has shown to be responsible for the pathological reaction, which may lead to septic shock. For biological activity, the expression of both subunits of IL-12, p35 and p40, is required. Moreover, the p40 chain of IL-12 specifically inhibits the effects of the IL-12 heterodimer. In this study, we investigated the effects of PTX on the production of both proinflammatory (TNF-alpha, IL-6, IL-12) and anti-inflammatory (IL-10) cytokines by murine macrophages (M&phi;). We have found that PTX, at concentrations below 100 microg/ml, selectively inhibited the production of TNF-alpha. Forskolin, a cAMP-elevating agent, similarly affected the production of the cytokines tested. However, at higher concentrations, PTX inhibited the production of TNF-alpha, IL-10, and IL-12 p35, but surprisingly, PTX enhanced the production of IL-12 p40. Concentrations of IL-10 were negatively correlated with the concentrations of IL-12 p40 subunit. These results further confirm the relevance of the use of PTX in clinical trials of immunological disorders characterised by inappropriate Th1 type immune responses.

CD14+CD16+ monocyte subpopulation in Kawasaki disease

Kawasaki disease (KD) is an acute febrile illness caused by vasculitis, occurring in early childhood. We have demonstrated that the activation of monocytes/macrophages plays a central role during acute KD. Recently, it has been reported that the CD14+CD16+ monocyte subpopulation plays a more important role in inflammation. In this study, we investigated the peripheral blood CD14+CD16+ monocyte subpopulation by flow cytometry, and serum levels of IL-10 and IL-12 using a sandwich ELISA in 28 KD patients. We also investigated this subpopulation in patients with bacterial infections, mononucleosis and anaphylactoid purpura, since the cause of KD remains unknown. We observed an increase in the number of CD14+CD16+ monocytes with acute KD, which was a positive correlation with C-reactive protein levels, and we observed only the patients with severe bacterial infections had increased this subpopulation during the acute stage among control diseases. In addition, we found that the serum levels of IL-10, but not IL-12, were higher during acute KD. These data suggest that increased peripheral blood CD14+CD16+ monocytes are part of the regulatory system of monocyte function during acute KD.

Pentoxifylline improves bacterial clearance during hemorrhage and endotoxemia

OBJECTIVE

The aim of this study was to investigate whether the methylxanthine-derivative pentoxifylline (PTX) affects bacterial clearance of the organism in states of hemorrhage and endotoxemia.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Experimental laboratory in a university hospital.

SUBJECTS

Fifty-four female chinchilla rabbits.

INTERVENTIONS

To quantify the clearance process, defined numbers (10(7) CFO) of Escherichia coli bacteria were injected intravenously into anesthetized rabbits, 60 mins after induction of hemorrhage (n = 9 + 3) or infusion of endotoxin (lipopolysaccharide [LPS]; 40 microg/kg/hr; n = 9 + 3) and after saline infusion (control; n = 9), respectively. Hemorrhage was induced by bleeding, standardized by defined reduction of mean arterial pressure (30% of baseline value). To evaluate the potential effects of PTX on bacterial elimination and killing, in states of hemorrhage and endotoxemia, blood clearance of E. coli and colonization of different organs were investigated after pretreatment with PTX (30 mg/kg) as a bolus injection followed by continuous infusion of PTX (50 mg/kg/hr) in hemorrhagic (n = 9) and endotoxemic rabbits (n = 9). Three additional experiments were performed to evaluate the effects attributable to PTX itself.

MEASUREMENTS AND MAIN RESULTS

Parameters monitored were rates of bacterial and LPS elimination from the blood, arterial blood pressure, blood gases, and serum lactate concentrations. Additionally, flow cytometric analysis of respiratory burst activity was performed. Three hours after bacterial injection, the animals were killed, and tissue samples of liver, kidney, spleen, and lung were collected for bacteriologic examinations. Compared with the controls, hemorrhage and endotoxemia resulted in a significantly prolonged elimination of injected E. coli from the blood. The delayed blood clearance was associated with a significantly (p < .01) higher bacterial colonization of all organs, which was most pronounced in the lung. Pretreatment with PTX slightly enhanced blood clearance of E. coli as well as of LPS, and significantly reduced (p < .05) the colonization of lung and kidney after hemorrhage and endotoxemia. Furthermore, PTX suppressed polymorphonuclear neutrophil respiratory burst activity.

CONCLUSIONS

Hemorrhage and endotoxemia induce impaired bacterial clearance from blood and tissue. Treatment with PTX may reduce the risk of bacterial infections by attenuating bacterial colonization of organs in states of hemorrhage and endotoxemia.

Effect of the immunomodulating agent, pentoxifylline, in the treatment of sepsis in prematurely delivered infants: a placebo-controlled, double-blind trial

OBJECTIVE

To evaluate the influence of the methylxanthine derivative, pentoxifylline, on plasma levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, and IL-6 in prematurely delivered infants with generalized bacterial infections and to assess the effect of this immunomodulating drug on the clinical outcome in newborns with sepsis.

DESIGN

A prospective, randomized, double-blind trial.

SETTING

The neonatal intensive therapy units in university teaching hospitals.

PATIENTS

One hundred patients with sepsis admitted during a 1.5-yr period.

INTERVENTIONS

Patients were randomly assigned to receive pentoxifylline (pentoxifylline group) in a dose of 5 mg/kg/hr for 6 hrs on 6 successive days or an identically presented placebo (placebo group).

MEASUREMENTS AND MAIN RESULTS

Only infants with sepsis confirmed by positive blood culture were recruited into the study. There were no significant differences at randomization between the pentoxifylline and placebo groups with regard to the birth weight, gestational age, gender, Apgar score, hypotension, neutropenia, thrombocytopenia, metabolic acidosis, plasma levels of cytokines, and occurrence of shock. Plasma levels of TNF, IL-1, and IL-6 were evaluated before and after the drug or placebo administration on the first, third, and sixth days of therapy. Cytokines were determined by immunoenzymetric test EASIA (TNF) and Endogen Interleukin-Elisa (IL-1, IL-6). The frequency of gram-negative sepsis was similar in both groups (37.5% and 36.8%). Pentoxifylline significantly diminished plasma TNF levels (p = .009) but had no effect on plasma IL-1 levels. Mean plasma IL-6 levels, which were measured in the pentoxifylline group on the 6th day of the study, were significantly lower compared with respective data obtained in the placebo group. Only 1 of 40 infants with sepsis in the pentoxifylline group died, whereas 6 of 38 infants in the placebo group did not survive (p = .046). An increased incidence of disordered peripheral circulation and metabolic acidosis (p = .048), anuria or oliguria (p = .03), disseminated intravascular coagulation (p = .043), and the occurrence of clinical symptoms of necrotizing enterocolitis (p = .025) was observed in the course of sepsis in infants in the placebo group.

CONCLUSION

Pentoxifylline significantly affects the synthesis of TNF and IL-6 as well as reduces the mortality rate in premature infants with sepsis. The dosage and schedule of drug administration in this study attenuated the severity of the clinical course of sepsis in this group of patients.

Urinary protein excretion and serum tumor necrosis factor in diabetic patients with advanced renal failure: effects of pentoxifylline administration

In 24 diabetic patients with advanced renal failure (creatinine clearance [C(Cr)] < 35 mL/min), we prospectively studied serum tumor necrosis factor-alpha (TNF-alpha) levels, the possible relationship with urinary protein excretion, and the effects of pentoxifylline (PTF) administration. PTF (400 mg daily) was administered for 6 months to 14 patients, and the results were compared with data from a control group (n = 10). Baseline parameters were similar in both groups. At the end of the study, urinary protein excretion and serum TNF-alpha decreased in the active group from 2.7 (1.2 to 5.8) g/d and 569 +/- 285 pg/mL to 1.1 (0.3 to 4.0) g/d and 329 +/- 232 pg/mL, respectively (P < 0.001). By contrast, proteinuria and TNF-alpha did not change in the control group. Regression analysis showed a significant correlation between proteinuria and serum TNF-alpha both at basal (r = 0.55) and at the sixth month (r = 0.57). Furthermore, the reduction of urinary protein excretion was strongly correlated with the decrease of TNF-alpha (r = 0.72, P < 0.01). Serum Cr and C(Cr) remained stable in both groups during the study. Our findings suggest that cytokines might play a role in renal damage in diabetic nephropathy. PTF is effective in reducing proteinuria in diabetic patients with advanced renal failure. The anticytokine activity of PTF may be a further explanation for this antiproteinuric effect.

Pentoxifylline inhibits TNF-alpha production from human alveolar macrophages

Tumor necrosis factor-alpha (TNF-alpha) is an important proinflammatory cytokine. Recently, pentoxifylline (POF) has been shown to suppress the synthesis of TNF-alpha from lipopolysaccharide (LPS)-stimulated human monocytes in cell cultures and in vivo. The aim of this study was to investigate whether POF-induced suppression of TNF-alpha secretion affects peripheral blood monocytes (PBM) and alveolar macrophages (AM) equally, and whether POF is able to suppress the spontaneous TNF-alpha production from AM in pulmonary sarcoidosis in vitro. In seven patients without interstitial lung disease we studied the effect of POF on LPS-stimulated PBM and AM cultured for 24 h. In six patients with sarcoidosis we investigated the effect of POF on the enhanced spontaneous TNF-alpha production by AM in vitro. POF induced a dose-dependent suppression of the LPS-stimulated TNF-alpha production which was not different for PBM and AM, respectively. In sarcoidosis, POF inhibited the spontaneous TNF-alpha production of AM at 0.1 mM by 91% and at 1 mM by 98%. In conclusion, POF inhibits LPS-induced TNF-alpha production from PBM and AM to a similar extent and can also inhibit the exaggerated spontaneous TNF-alpha production from AM in sarcoidosis in vitro. This may be the basis for further clinical trials to evaluate POF as an immunotherapeutic agent in sarcoidosis.

The differential effect of pentoxifylline on cytokine production by alveolar macrophages and its clinical implications

The aim of this study was to investigate the effects of pentoxifylline (PTX) on the production of TNF-alpha, IL-1 beta, IL-6 and GM-CSF by lipopolysaccharide (LPS)-stimulated alveolar macrophages (AM). AM and peripheral blood monocytes (PBM) from 10 patients were cultured for 24 h in the presence of LPS (10 micrograms ml-1) and PTX at concentrations of 2.0 mM, 1.0 mM, 0.5 mM, 0.1 mM and 0.01 mM. TNF-alpha and GM-CSF were measured from the culture supernatants of both the AM and PBM from all 10 patients and IL-1 beta and IL-6 from the culture supernatants of the AM from five patients. The TNF-alpha production by AM was significantly suppressed in the presence of PTX at concentrations of 2.0 and 1.0 mM, while production of IL-1 beta, IL-6 and GM-CSF remained unaffected. In PBM cultures, PTX significantly suppressed the production of TNF-alpha and GM-CSF, at all tested concentrations. The present study provides evidence that PTX selectively suppresses the production of TNF-alpha by LPS-stimulated AM and may have a role in the treatment of lung diseases where TNF-alpha is involved. The mode of administration of PTX should take into account the suppressive effect of this drug on GM-CSF production by PBM.

Corticosteroid-independent inhibition of tumor necrosis factor production by the neuropeptide urocortin

Urocortin (UCN) is a neuropeptide homologous with corticotropin-releasing factor (CRF), which has anti-inflammatory activities not all mediated by corticosteroids. In mice, UCN (1 microg/mouse sc) significantly reduced lipopolysaccharide (LPS)-induced serum tumor necrosis factor (TNF) and interleukin (IL)-1beta levels in vivo but did not affect serum IL-6. These effects were paralleled by a rise in corticosterone (CS) levels. Blockade of the CS increase by cyanoketone did not prevent TNF inhibition by UCN, suggesting the neuropeptide has anti-inflammatory mechanisms independent of the hypothalamus-pituitary-adrenal axis. In fact UCN had a direct inhibitory effect on LPS-induced TNF in rat Kupffer cells at concentrations between 10(-10) and 10(-16) M, and this effect was related to increased cAMP levels. However, the in vivo inhibition of LPS-induced IL-1beta by UCN was reversed by cyanoketone, indicating that the increase of endogenous glucocorticoids might be more important in IL-1beta inhibition than in TNF inhibition by UCN.

Novel Insights Into the Pathogenesis and Therapy of Circulatory Shock

Several lines of evidence suggest central roles for nitric oxide, oxygen free radicals, cytokines, and adhesion molecules in circulatory shock. Lipid peroxidation fre quently accompanies ischemia-reperfusion injury; re cruitment of leukocytes exposed to ischemia-reperfu sion injury is largely dependent on leukocytes and endothelial cell adhesion interaction, enhanced nitric oxide stimulation by proinflammatory cytokines contrib utes to increased gut mucosal permeability in sepsis, and tumor necrosis factor (TNF) administration mimics the hemodynamic changes characteristic of circulatory shock. Recent advances in molecular and cellular biol ogy have paved the way for innovative approaches to the treatment of circulatory shock. Novel pharmaco logic approaches are being directed at three distinct levels of the inflammatory cascade: the inciting insult (ie, endotoxin), the mediators (ie, TNF, interleukin-1, oxygen free radicals), and the effector cells (ie, neutro phils). The intent of this review is to discuss the biology of mediators in circulatory shock as well as the experi mental and clinical evidence implicating their role in development and pathogenesis of the injury. Current status of novel adjunctive therapies for circulatory shock is reviewed.

Treatment of endotoxic shock: glucocorticoids, lazaroids, nonsteroidals, others

Review of the literature would indicate that a therapy inhibiting a single step in the inflammatory mediator cascade, although potentially beneficial, cannot serve as the "magic bullet" in endotoxic shock. Thus, combination therapy using drugs that target multiple steps in the mediator cascade may prove useful in the future. Until controlled clinical studies have been performed in veterinary medicine using the agents discussed in this manuscript (or others), many questions will remain regarding the best possible pharmacologic therapies to use in supplementing traditional supportive care (e.g., fluids, broad-spectrum antimicrobials) measures. Many of the therapies discussed in this manuscript hold tremendous potential, but must be administered before endotoxic shock occurs or early in the course of endotoxic shock to elicit a beneficial response. Unfortunately this is not usually possible in the clinical situation. Further, the possibility of eliciting a detrimental response by use of drugs at inappropriate dosages or too late in the course of the disease must be considered. In time, therapies may be grouped into those that hold promise for being beneficial in the patient at risk for endotoxic shock and those that are beneficial for treatment of established endotoxic shock. Therapies that may hold promise for the patient with established endotoxic shock possibly include the lazaroids, certain NSAIDs, pentoxifylline, and selective inhibitors of iNOS activity. Although still controversial, methylprednisolone and other glucocorticoids are probably best reserved for the patient at risk for endotoxic shock, or those identified very early in the course of endotoxemia and endotoxic shock, and should never be used in conjunction with NSAIDs. Since no one therapy is likely to provide the "magic bullet" for the patient in endotoxic shock, treatment may ultimately involve combination therapy using some of these drugs that target different pathways and mediators and may also include antibodies against endotoxin or its mediators.

Pentoxifylline treatment attenuates pulmonary vasomotor dysfunction in acute lung injury

Acute lung injury (ALI) is characterized by pulmonary hypertension. Although the pathophysiology of ALI is complex, cytokine production, especially tumor necrosis factor-alpha (TNF-alpha), is known to mediate histologic lung injury. Pentoxifylline (PTX) is known to inhibit the expression of many cytokines, including TNF-alpha. The purpose of this study was to determine the effect of PTX treatment on endotoxin-induced impairment of endothelium-dependent mechanisms of pulmonary vasorelaxation. Mechanisms of endothelium-dependent relaxation were studied with the muscarinic receptor agonist, acetylcholine (ACh), and the receptor-independent calcium ionophore, A23187. Endothelium-independent pulmonary vasorelaxation was examined by direct stimulation of smooth muscle guanylate cyclase with the nitric oxide donor, sodium nitroprusside (SNP). Five rats received PTX (50 mg/kg) and endotoxin (20 mg/kg), endotoxin alone, or saline ip. After 6 hr, dose-response curves to ACh, A23187, and SNP were determined in isolated pulmonary artery rings preconstricted with phenylephrine (PE). PTX attenuated but did not eliminate endotoxin-induced impairment of endothelium-dependent and -independent pulmonary vasorelaxation. These data suggest that PTX may offer a therapeutic modality for the treatment of pulmonary hypertension in ALI.

Phosphodiesterase inhibition overcomes pulmonary vasomotor dysfunction in acute lung injury

Production of cGMP is impaired in endotoxin-induced acute lung injury. This results in dysfunction of endothelium-dependent and -independent cGMP-mediated pulmonary vasorelaxation and, therefore, pulmonary hypertension. We hypothesized that cyclic nucleotide phosphodiesterase (PDE) inhibition would attenuate endotoxin-induced impairment to cGMP-mediated mechanisms of pulmonary vasorelaxation. The purpose was to examine the effect of stimulating cGMP production with concurrent inhibition of cGMP catabolism by PDE inhibition following endotoxin-induced acute lung injury. Isolated pulmonary arterial rings from rats (n = 5) were studied 6 hrs after endotoxin (20 mg/kg ip) or saline. In a third group (n = 5), PDE inhibition was accomplished with in vitro 3-isobutyl-1-methylxanthine (IBMX, 1 microM for 30 min). Cyclic GMP-mediated relaxation was interrogated by stimulating (1) endothelium-dependent mechanisms with the receptor-dependent agonist acetylcholine and the receptor-independent agonist A23187, a calcium ionophore, and an (2) endothelium-independent mechanism with sodium nitroprusside. PDE inhibition attenuated endotoxin-induced vasomotor dysfunction. A two-pronged approach-stimulating cGMP production and preventing cGMP catabolism with PDE inhibition-may offer a therapeutically accessible mechanism to overcome vasomotor dysfunction in acute lung injury.