Influence of pentoxifylline on cytokine levels and inflammatory parameters in septic shock

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.

Can magnesium sulfate prophylaxis reduce colistin nephrotoxicity?

The study aimed to investigate the role of magnesium sulfate prophylaxis in nephrotoxicity caused by colistin. Thirty Wistar Albino rats were divided into four groups: control, colistin, magnesium (Mg), and Mg+colistin. The drugs were administered to the groups for seven days. Urea-creatinine values were measured at the beginning (T0) and end (T1) of the study. Malondialdehyde (MDA) levels were measured in plasma and kidney tissue, glutathione (GSH) levels were analyzed in the erythrocyte and kidney tissues. At the end of the study, the semiquantitative score (SQS) was calculated by the histopathological examination of the kidneys. Urea values significantly decreased in Mg and Mg+colistin groups compared to the baseline (p=0.013 and p=0.001). At the time of T1, these groups had significantly lower urea values than the colistin and control groups. Creatinine value was significantly increased in the colistin group compared to baseline (p=0.005), the creatinine value in the colistin group was significantly higher than the Mg+colistin group (p=0.011). Plasma MDA levels were significantly higher in the colistin group compared to the other groups at the time of T1 (p<0.001). The Mg+colistin group had lower renal MDA levels than the colistin group. The colistin group had significantly higher renal tubular grade (p=0.035), renal affected area (p<0.001), and SQS (p=0.001) than the Mg+colistin group. The results of the study suggested that Mg sulfate may have a nephrotoxicity-reducing effect on colistin.

Can magnesium sulfate prophylaxis reduce colistin nephrotoxicity?

The study aimed to investigate the role of magnesium sulfate prophylaxis in nephrotoxicity caused by colistin. Thirty Wistar Albino rats were divided into four groups: control, colistin, magnesium (Mg), and Mg+colistin. The drugs were administered to the groups for seven days. Urea-creatinine values were measured at the beginning (T0) and end (T1) of the study. Malondialdehyde (MDA) levels were measured in plasma and kidney tissue, glutathione (GSH) levels were analyzed in the erythrocyte and kidney tissues. At the end of the study, the semiquantitative score (SQS) was calculated by the histopathological examination of the kidneys. Urea values significantly decreased in Mg and Mg+colistin groups compared to the baseline (p=0.013 and p=0.001). At the time of T1, these groups had significantly lower urea values than the colistin and control groups. Creatinine value was significantly increased in the colistin group compared to baseline (p=0.005), the creatinine value in the colistin group was significantly higher than the Mg+colistin group (p=0.011). Plasma MDA levels were significantly higher in the colistin group compared to the other groups at the time of T1 (p<0.001). The Mg+colistin group had lower renal MDA levels than the colistin group. The colistin group had significantly higher renal tubular grade (p=0.035), renal affected area (p<0.001), and SQS (p=0.001) than the Mg+colistin group. The results of the study suggested that Mg sulfate may have a nephrotoxicity-reducing effect on colistin.

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.

Intravenous magnesium sulfate: new method in prevention of contrast-induced nephropathy in primary percutaneous coronary intervention

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is an adverse consequence of percutaneous coronary interventions which results in significant morbidity and mortality and adds to the costs of diagnostic and interventional cardiology procedures. Various pathophysiological mechanisms have been proposed for CI-AKI and various agents tested for its prevention. There is currently a general agreement that adequate pre-procedural hydration constitutes the cornerstone of prevention, yet there are reports of the use of some other agents with various efficacies. We prospectively tested IV magnesium sulfate (Mg) for CI-AKI prevention.

METHOD AND DESIGN

This study is a prospective, randomized, open-labeled, single-center clinical trial. We randomly assigned 122 consecutive patients to two groups. The first group was the control group with routine treatment (n = 64), and second group was the study group with routine treatment plus IV magnesium sulfate 1 g just before the procedure (n = 62). Serum creatinine was measured before the procedure and 2 days after the procedure. The primary end point was the occurrence of CI-AKI within 48 h. CI-AKI was defined as 0.5 mg/dl or more increase in serum creatinine or 25% or more increase above baseline serum creatinine. There was no difference in definition if both of these parameters were present.

RESULTS

The control and study groups were comparable in the overall predicted risk of CI-AKI. Also, the type and volume of the contrast were not significantly different between the two groups. Following angioplasty, CI-AKI occurred in 17 (26.6%) patients in the control group and nine (14.5%) patients in the study group; there was a significant reduction in CI-AKI in the study group (P = 0.01). Additionally, there was no mortality or a need for hemodialysis in either group.

CONCLUSION

In primary PCI patients, the prophylactic use of intravenous Mg can be recommended to be added to traditional hydration for CI-AKI prevention.

Preparation of antiferromagnetic Co3O4 nanoparticles from two different precursors by pyrolytic method: in vitro antimicrobial activity

Two varieties of Co₃O₄ nano particles (Co₃O₄-I and Co₃O₄-II) have been synthesized from two different precursors using a pyrolytic technique and their magnetic and in vitro antimicrobial activity have been investigated.

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.

Efficacy of pentoxifylline in prevention of contrast-induced nephropathy in angioplasty patients

BACKGROUND

Contrast-induced nephropathy (CIN) is an adverse consequence of contrast media use that results in significant morbidity and mortality and adds significant costs to diagnostic and interventional cardiology procedures. Various pathophysiological mechanisms have been proposed for CIN and various agents have been tested for its prevention. There is currently a general agreement that adequate pre-procedure hydration constitutes the cornerstone of prevention, yet there are reports of the use of some other agents with various efficacies. We prospectively tested pentoxifylline (PTX), an antioxidant, anti-inflammatory drug, for CIN prevention in patients undergoing coronary angioplasty.

MATERIALS AND METHODS

In this prospective, randomized, single-blind, single-center clinical trial, 286 consecutive patients were randomly assigned to the control group (n = 146), with routine treatment and no PTX, or the study group (n = 140), with routine treatment and PTX, 400 mg/tid from 24 h before to 24 h after coronary angioplasty. Serum creatinine was measured before and 2 days after the procedure. The primary end point was the occurrence of CIN within 48 h.

RESULTS

The control and PTX groups were comparable in the overall predicted risk of CIN. Also, the type and volume of the contrast agent were not significantly different between the two groups. Following angioplasty, CIN occurred in 20 (13.69%) patients in the control group and in 12 (8.5%) patients in the study group; the difference was not statistically significant (P = 0.17). Additionally, there was no mortality and need for hemodialysis in either group.

CONCLUSION

In angioplasty patients, the prophylactic oral use of PTX could be recommended for CIN prevention, although no statistically significant protective effect was documented.

Beneficial Effect of Pentoxifylline on Cisplatin-Induced Acute Renal Failure in Rabbits

Pentoxifylline (PTX) has been reported to inhibit TNF-alpha production and prevent several types of acute renal failure. This study was undertaken to determine the effect of PTX on the cisplatin-induced acute renal failure in rabbits. Rabbits received a single injection of cisplatin (5 mg/kg, i.p.) with or without PTX pretreatment (30 mg/kg, i.v.). Alterations in renal function, apoptotic cell death, and TNF-alpha mRNA expression were measured at 24 or 48 h after cisplatin injection. Cisplatin caused an increase in BUN and serum creatinine levels, a reduction in GFR, and an increase in fractional Na+ excretion. Such changes were significantly attenuated by PTX pretreatment (30 mg/kg, i.p.) 30 min before and 24 h after cisplatin injection. Morphological evaluation showed that cisplatin injection induced diffuse proximal tubular necrosis and the effect was reduced by PTX pretreatment. Cisplatin induced apoptotic cell death in renal cortex and the effect was significantly prevented by PTX. Treatment of opossum kidney cells with cisplatin resulted in cell death, which was significantly prevented by PTX. The increase in lipid peroxidation and the decrease in renal blood flow induced by cisplatin were not affected by PTX. The expression of TNF-alpha mRNA was increased after cisplatin injection and the effect was inhibited by PTX pretreatment. These results suggest that cisplatin-induced acute renal failure in rabbits is associated with an induction of TNF-alpha-mediated apoptosis, and that PTX may exert a protective effect against cisplatin nephrotoxicity by inhibiting TNF-alpha production.

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.

Ascending placentitis in the mare: A review

Ascending placentitis is a condition that occurs late in pregnancy when bacteria enter the sterile uterus from the lower reproductive tract. It leads to abortion or the birth of premature and weakened foals. Early detection and treatment of this condition is vital for ensuring the production of a viable foal.

Mares with ascending placentitis often present in late term pregnancy with signs of premature udder development and premature lactation. There may be a vulvar discharge. Early detection of placental problems is possible using trans-abdominal or trans-rectal ultrasonography. Hormones such as progesterone and relaxin may be measured as indicators of foetal stress and placental failure. Postpartum foetal membranes may be thickened and contain a fibronecrotic exudate. The region most affected is the cervical star. Definitive diagnosis of ascending placentitis is by histopathological examination of the chorioallantoic membrane.

Ideal treatment strategies are aimed at curing the infection and prolonging the pregnancy to as close to term as possible and consist of anti-microbials, anti-inflammatories and hormonal support.

Swabs are taken from affected mares to determine antibiotic sensitivity and to aid in treatment of foals born from these mares which are at risk of becoming septic. If detected early enough, the chances of producing a viable foal are greatly increased.

Zinc-dependent suppression of TNF-alpha production is mediated by protein kinase A-induced inhibition of Raf-1, I kappa B kinase beta, and NF-kappa B

Excessive and permanent cytokine production in response to bacterial LPS causes cell and tissue damage, and hence organ failure during sepsis. We have previously demonstrated that zinc treatment prevents LPS-induced TNF-alpha expression and production in human monocytes by inhibiting cyclic nucleotide phosphodiesterase (PDE) activity and expression, and subsequent elevation of the cyclic nucleotide cGMP. In the present study, we investigated the molecular mechanism by which cGMP signaling affects the LPS-induced signaling cascade to suppress TNF-alpha transcription and release from monocytes. Zinc-mediated cGMP elevation led to cross activation of protein kinase A. This zinc-induced protein kinase A activation inhibited Raf-1 activity by phosphorylation at serine 259, preventing activation of Raf-1 by phosphorylation of serine 338. By this mechanism, zinc suppressed LPS-induced activation of IkappaB kinase beta (IKKbeta) and NF-kappaB, and subsequent TNF-alpha production. Our study shows that PDE inhibition by zinc modulates the monocytic immune response by selectively intervening in the Raf-1/IKKbeta/NF-kappaB pathway, which may constitute a common mechanism for the anti-inflammatory action of PDE inhibitors.

Antiinflammatory Therapies for Cystic Fibrosis: Past, Present, and Future

Inflammation is a major component of the vicious cycle characterizing cystic fibrosis pulmonary disease. If untreated, this inflammatory process irreversibly damages the airways, leading to bronchiectasis and ultimately respiratory failure. Antiinflammatory drugs for cystic fibrosis lung disease appear to have beneficial effects on disease parameters. These agents include oral corticosteroids and ibuprofen, as well as azithromycin, which, in addition to its antimicrobial effects, also possesses antiinflammatory properties. Inhaled corticosteroids, colchicine, methotrexate, montelukast, pentoxifylline, nutritional supplements, and protease replacement have not had a significant impact on the disease. Therapy with oral corticosteroids, ibuprofen, and fish oil is limited by adverse effects. Azithromycin appears to be safe and effective, and is thus the most promising antiinflammatory therapy available for patients with cystic fibrosis. Pharmacologic therapy with antiinflammatory agents should be started early in the disease course, before extensive irreversible lung damage has occurred.

Pharmacological inhibition of Mannheimia haemolytica lipopolysaccharide and leukotoxin-induced cytokine expression in bovine alveolar macrophages

The inflammatory cytokines tumor necrosis factor-alpha (TNFalpha), interleukin-1 beta (IL-1beta), and interleukin-8 (IL-8) are believed to contribute to the pathogenesis of lung injury in bovine pneumonic mannheimiosis (BPM) caused by Mannheimia (Pasteurella) haemolytica. Inflammatory cytokines may, therefore, represent therapeutic targets to be modulated for the purpose of treating or preventing this important disease of cattle. The purpose of this study was to evaluate the ability of six pharmacological agents to suppress the expression of TNFalpha, IL-1beta, and IL-8 genes and proteins in bovine alveolar macrophages (AM) exposed to M. haemolytica lipopolysaccharide (LPS) and leukotoxin (LktA) in vitro. The compounds tested included dexamethasone (DEX), tetrahydropapaveroline (THP), pentoxifylline (PTX), rolipram (ROL), SB203580 (SB), and thalidomide (THL). Cytokine expression was induced by the addition of purified M. haemolytica LPS and LktA to AM cell cultures following pretreatment with inhibitor compounds. Secretion of TNFalpha, IL-1beta, and IL-8 proteins into the cell culture supernatant was measured using enzyme-linked immunosorbent assays, and steady-state accumulation of cytokine-specific mRNA was measured by northern blot analysis. Dose-dependent inhibition of cytokine secretion occurred in response to pretreatment of AM with DEX (TNFalpha, IL-1beta, IL-8), THP (TNFalpha, IL-1beta, IL-8), PTX (TNFalpha, IL-1beta, IL-8), ROL (TNFalpha, IL-1beta), and SB (TNFalpha, IL-8). Significant dose-dependent inhibition of cytokine mRNA expression occurred in response to pretreatment with DEX (TNFalpha, IL-1beta, IL-8), THP (TNFalpha, IL-1beta, IL-8), and PTX (TNFalpha). DEX was the most effective inhibitor by far; pretreatment with this compound yielded greater than 95% inhibition of cytokine gene and protein expression over a broad range of concentrations. These findings demonstrate that DEX, THP, PTX, ROL, and SB are capable of suppressing inflammatory cytokine secretion by bovine AM in vitro. If pulmonary cytokine secretion may be similarly inhibited in vivo, anti-cytokine therapy may represent a novel strategy for the management of BPM.

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.

Procalcitonin, C-reactive protein, and endotoxin after bone marrow transplantation: identification of children at high risk of morbidity and mortality from sepsis

We prospectively evaluated the capacity of serum procalcitonin (PCT), compared with serum levels of C-reactive protein (CRP) and endotoxin, to identify children at high risk for mortality from sepsis after BMT. Of 47 pediatric bone marrow transplantation patients studied, 22 had an uneventful course post-transplant (Group 1), 17 survived at least one septic event (Group 2), and eight died from multiorgan failure (MOF) following septic shock (Group 3). Median concentrations of PCT over the course of the study were 1.3, 15.2, and 102.8 ng/ml, respectively, in each of the three groups (P<0.002 for each comparison). Median concentrations of CRP were 91, 213, and 260 mg/l, respectively (P<0.001 for Group 1 vs Group 2 and Group 3; P=NS for Group 2 vs Group 3). Median concentrations of endotoxin were 0.21, 0.30, and 0.93 U/l, respectively (P=NS for each comparison). Median concentrations of PCT, in contrast to serum CRP and endotoxin, correlated with the severity of sepsis (8.2 ng/ml in 'sepsis' and 22.3 ng/ml in 'severe sepsis', P=0.028) and provided useful prognostic information during septic episodes.

Immunopharmacological potential of selective phosphodiesterase inhibition. I. Differential regulation of lipopolysaccharide-mediated proinflammatory cytokine (interleukin-6 and tumor necrosis factor-alpha) biosynthesis in alveolar epithelial cells

In an attempt to elaborate in vitro on a therapeutic strategy that counteracts an inflammatory signal, we previously reported a novel immunopharmacological potential of glutathione, an antioxidant thiol, in regulating inflammatory cytokines. In the present study, we investigated the hypothesis that selective regulation of phosphodiesterases (PDEs), a family of enzymes that controls intracellular cAMP/cGMP degradation, differentially regulates proinflammatory cytokines. Selective PDE1 inhibition (8-methoxymethyl-3-isobutyl-1-methylxanthine) blockaded lipopolysaccharide-endotoxin (LPS)-mediated biosynthesis of interleukin (IL)-6, but this pathway had no inhibitory effect on tumor necrosis factor-alpha (TNF-alpha). Furthermore, inhibition of PDE3 (amrinone) abolished the effect of LPS on IL-6, but attenuated TNF-alpha production. Reversible competitive inhibition of PDE4 (rolipram) exhibited a potent inhibitory effect on IL-6 and a dual, biphasic (excitatory/inhibitory) effect on TNF-alpha secretion. Blockading PDE5 (4-[[3',4'-(methylenedioxy)benzyl] amino]-6-methoxyquinazoline) showed a high potency in reducing IL-6 production, but in a manner similar to the inhibition of PDE4, exhibited a biphasic effect on TNF-alpha biosynthesis. Simultaneous inhibition of PDE5, 6, and 9 (zaprinast), purported to specifically elevate intracellular cGMP, reduced, in a dose-independent manner, IL-6 and TNF-alpha biosynthesis. Finally, nonselective inhibition of PDE by pentoxifylline suppressed LPS-mediated secretion of IL-6 and TNF-alpha. The involvement of specific PDE isoenzymes in differentially regulating LPS-mediated inflammatory cytokine biosynthesis indicates a novel approach to unravel the potential therapeutic targets that these isozymes constitute during the progression of inflammation within the respiratory epithelium.

Effect of pentoxifylline on ischemic acute renal failure in rabbits

Previous studies have demonstrated that levels of tumor necrosis factor-alpha (TNF-alpha) or its mRNA expression are increased in acute renal failure of various types including ischemia/reperfusion injury. This study was undertaken to determine whether pentoxifylline (PTX), an inhibitor of TNF-alpha production, provides a protective effect against ischemic acute renal failure in rabbits. Renal ischemia was induced by clamping bilateral renal arteries for 60 min. Animals were pretreated with PTX (30 mg/kg, i.v.) 10 min before release of clamp. At 24 h of reperfusion of blood after ischemia, changes in renal function, renal blood flow, and the expression of TNF-alpha mRNA were evaluated. Ischemia/reperfusion caused a marked reduction in GFR, which was accompanied by an increase of serum creatinine levels. Such changes were significantly attenuated by PTX pretreatment. PTX ameliorated the impairment of renal tubular function, but it had no effect on the reduction of renal blood flow induced by ischemia/reperfusion. The protective effect of PTX on functional changes was supported by morphological studies. The impairment of glucose and phosphate reabsorption in postischemic kidneys was associated with a depression in the expression of Na+-glucose and Na+-Pi transporters. The expression of TNF-alpha mRNA was increased after reperfusion, which was inhibited by PTX pretreatment. The PTX pretreatment in vitro prevented the release of lactate dehydrogenase induced by an oxidant t-butylhydroperoxide in rabbit renal cortical slices, but it did not produce any effect on the oxidant-induced lipid peroxidation, suggesting that PTX protection is not resulted from its antioxidant action. These results suggest that PTX may exert a protective effect against ischemic acute renal failure by inhibiting the production of TNF-alpha in rabbits.

Effects of vesnarinone on peripheral circulating levels of cytokines and cytokine receptors in patients with heart failure: a report from the Vesnarinone Trial

STUDY OBJECTIVES

Proinflammatory cytokines may contribute to disease progression in heart failure by virtue of the direct toxic effects that these molecules exert on the heart and the circulation. Accordingly, there is interest in developing therapeutic agents with anticytokine properties that might be used as adjunctive therapy to modulate proinflammatory cytokine levels in patients with heart failure. Previous experimental studies suggested that vesnarinone has potent anticytokine properties in vitro. Therefore, we examined the effects of vesnarinone on circulating levels of cytokines and cytokine receptors in a large-scale, multicenter, clinical trial of patients with moderate-to-advanced heart failure: the Vesnarinone Trial (VEST).

METHODS

Circulating levels of tumor necrosis factor (TNF)-alpha, soluble TNF-receptor type 1, soluble TNF-receptor type 2, as well as interleukin (IL)-6 and soluble IL-6 receptor (sIL-6R) were measured on plasma samples by enzyme-linked immunosorbent assay at baseline and at 24 weeks in patients who were receiving placebo (n = 352), 30 mg of vesnarinone (n = 367), and 60 mg of vesnarinone (n = 327).

RESULTS

Treatment with 30 mg and 60 mg of vesnarinone had no effect on circulating levels of cytokines or cytokine receptors in patients with advanced heart failure over a 24-week period.

CONCLUSIONS

In contrast to the potent anticytokine effects observed with vesnarinone in experimental studies in vitro, the results of this clinical study suggest that vesnarinone does not have any measurable anticytokine effects in vivo in patients with moderate-to-advanced heart failure.

The phosphodiesterase inhibitors pentoxifylline and rolipram suppress macrophage activation and nitric oxide production in vitro and in vivo

We studied the effects of the phosphodiesterase inhibitors pentoxifylline (PTX) and rolipram (ROL) on nitric oxide (NO) production by macrophages and correlated this with cellular cAMP levels. The RAW 264.7 cell line or mouse peritoneal macrophages were activated with lipopolysaccharide (LPS) and interferon gamma (IFN gamma), with or without ROL, PTX, cAMP analogues, or Forskolin. In vivo, peritoneal macrophages were stimulated with staphylococcal enterotoxin B with or without administration of ROL. Nitrite levels in culture and the total cellular cAMP levels were measured. ROL and PTX suppressed NO production of LPS/IFN gamma-stimulated macrophages. ROL (IC(50) = 68-74 microM) was about 40 times more potent than PTX (IC(50) = 2.4-2.9 mM). The suppression paralleled increased total cellular cAMP level (EC(50) = 68-72 microM) and was mimicked by other cAMP elevating agents. ROL and PTX suppressed inducible NO synthase at the mRNA level. The inhibition of NO production of macrophages by ROL or PTX could be beneficial in NO-mediated inflammatory and/or autoimmune disorders.

Phosphodiesterase 4 inhibitors, structurally unrelated to rolipram, as promising agents for the treatment of asthma and other pathologies

An increase of cyclic adenosine and guanosine monophosphate (cAMP and cGMP) level can be achieved by inhibition of phosphodiesterases (PDEs), which are the enzymes responsible for the conversion of these second messengers into the corresponding 5-monophosphate inactive counterparts. The high heterogeneity in PDE families and in their tissue distribution, as well as their different functional role, make these enzymes very attractive targets for medicinal chemists. The PDE 4 family is particularly abundant in immunocompetent cells, where an increase of cAMP leads to the inhibition of the synthesis and release of pro-inflammatory mediators, cytokines and active oxygen species. Moreover PDE 4 inhibitors are able to reduce bronchial smooth muscle tone in vitro and show bronchodilatory effects in vivo. Thus, the current therapy for asthma, which is based on a combination of beta(2) agonists and corticosteroids, could be replaced by treatment with PDE 4 inhibitors. This review mainly covers PDE 4 inhibitors structurally related to xanthines and Nitraquazone, which appear to be very attractive models for the synthesis of novel PDE 4 inhibitors potentially useful for the treatment of asthma, chronic pulmonary obstructive disease and some autoimmune diseases. These compounds could be devoid of the central side-effects (nausea, vomiting, headache) of the archetypal Rolipram, which hampered its development as a drug. The review also highlights the novel structural classes of PDE 4 inhibitors recently reported in the literature.

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.

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.

Has the mortality of septic shock changed with time

OBJECTIVES

To determine whether a systematic review of the literature could identify changes in the mortality of septic shock over time.

DATA SOURCES

A review of all relevant papers from 1958 to August 1997, identified through a MEDLINE search and from the bibliographies of articles identified.

DATA SYNTHESIS

The search identified 131 studies (99 prospective and 32 retrospective) involving a total of 10,694 patients. The patients' mean age was 57 yrs with no change over time. The overall mortality rate in the 131 studies was 49.7%. There was an overall significant trend of decreased mortality over the period studied (r=.49, p < .05). The mortality rate in those patients with bacteremia as an entry criterion was greater than that rate in patients whose entry criterion was sepsis without definite bacteremia (52.1% vs. 49.1%; chi2=6.1 and p< .05). The site of infection altered noticeably over the years. Chest-related infections increased over time, with Gram-negative infections becoming proportionately less common. If all other organisms and mixed infections are included with the Gram-positives, the result is more dramatic, with these organisms being causative in just 10% of infections between 1958 and 1979 but in 31% of infections between 1980 and 1997.

CONCLUSIONS

The present review showed a slight reduction in mortality from septic shock over the years, although this result should be approached with caution. The heterogeneity of the articles and absence of a severity score for most of the studies limited our analysis. Furthermore, there was an increasing prevalence of Gram-positive causative organisms, and a change of the predominant origin of sepsis from the abdomen to the chest.

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.