Structure-based redesigning of pentoxifylline analogs against selective phosphodiesterases to modulate sperm functional competence for assisted reproductive technologies.

Phosphodiesterase (PDE) inhibitors, such as pentoxifylline (PTX), are used as pharmacological agents to enhance sperm motility in assisted reproductive technology (ART), mainly to aid the selection of viable sperm in asthenozoospermic ejaculates and testicular spermatozoa, prior to intracytoplasmic sperm injection (ICSI). However, PTX is reported to induce premature acrosome reaction (AR) and, exert toxic effects on oocyte function and early embryo development. Additionally, in vitro binding studies as well as computational binding free energy (ΔGbind) suggest that PTX exhibits weak binding to sperm PDEs, indicating room for improvement. Aiming to reduce the adverse effects and to enhance the sperm motility, we designed and studied PTX analogues. Using structure-guided in silico approach and by considering the physico-chemical properties of the binding pocket of the PDEs, designed analogues of PTX. In silico assessments indicated that PTX analogues bind more tightly to PDEs and form stable complexes. Particularly, ex vivo evaluation of sperm treated with one of the PTX analogues (PTXm-1), showed comparable beneficial effect at much lower concentration-slower AR, higher DNA integrity and extended longevity of  spermatozoa and  superior embryo quality. PTXm-1 is proposed to be a better pharmacological agent for ART than PTX for sperm function enhancement.

Nanoparticulate tablet dosage form of lisofylline-linoleic acid conjugate for type 1 diabetes: in situ single-pass intestinal perfusion (SPIP) studies and pharmacokinetics in rat.

Lisofylline (LSF) is an anti-inflammatory molecule with high aqueous solubility and rapid metabolic interconversion to its parent drug, pentoxifylline (PTX) resulting in very poor pharmacokinetic (PK) parameters, necessitating high dose and dosing frequency. In the present study, we resolved the physicochemical and pharmacokinetic limitations associated with LSF and designed its oral dosage form as a tablet for effective treatment in type 1 diabetes (T1D). Self-assembling polymeric micelles of LSF (lisofylline-linoleic acid polymeric micelles (LSF-LA PLM)) were optimized for scale-up (6 g batch size) and lyophilized followed by compression into tablets. Powder blend and tablets were evaluated as per USP. LSF-LA PLM tablet so formed was evaluated for in vitro release in simulated biological fluids (with enzymes) and for cell viability in MIN-6 cells. LSF-LA PLM in tablet formulation was further evaluated for intestinal permeability (in situ) along with LSF and LSF-LA self-assembled micelles (SM) as controls in a rat model using single-pass intestinal perfusion (SPIP) study. SPIP studies revealed 1.8-fold higher oral absorption of LSF-LA from LSF-LA PLM as compared to LSF-LA SM and ~5.9-fold higher than LSF (alone) solution. Pharmacokinetic studies of LSF-LA PLM tablet showed greater Cmax than LSF, LSF-LA, and LSF-LA PLM. Designed facile LSF-LA PLM tablet dosage form has potential for an immediate decrease in the postprandial glucose levels in patients of T1D.

Lisofylline mitigates cardiac inflammation in a mouse model of obesity through improving insulin secretion and activating cardiac AMPK signaling pathway.

Obesity has emerged as a leading cause of death in the last few decades, mainly due to associated cardiovascular diseases. Obesity, inflammation, and insulin resistance are strongly interlinked. Lisofylline (LSF), an anti-inflammatory agent, demonstrated protection against type 1 diabetes, as well as reduced obesity-induced insulin resistance and adipose tissue inflammation. However, its role in mitigating cardiac inflammation associated with obesity is not well studied. Mice were divided into 4 groups; the first group was fed regular chow diet, the second was fed regular chow diet and treated with LSF, the third was fed high fat diet (HFD), and the fourth was fed HFD and treated with LSF. Cardiac inflammation was interrogated via expression levels of TNF α, interleukins 6 and 10, phosphorylated STAT4 and lipoxygenases 12 and 12/15. Apoptosis and expression of the survival gene, AMPK, were also evaluated. We observed that LSF alleviated obesity-induced cardiac injury indirectly by improving both pancreatic ß-cell function and insulin sensitivity, as well as, directly via upregulation of cardiac AMPK expression and downregulation of cardiac inflammation and apoptosis. LSF may represent an effective therapy targeting obesity-induced metabolic and cardiovascular complications.

Scalable Self-Assembling Micellar System for Enhanced Oral Bioavailability and Efficacy of Lisofylline for Treatment of Type-I Diabetes.

The study summarizes the development of an orally active nanoformulation of a potent but one of the least explored molecules, lisofylline (LSF), in type 1 diabetes (T1D). LSF undergoes rapid metabolism, resulting in poor oral bioavailability and short half-life. In this work, to improve its pharmacokinetic (PK) properties, LSF was encapsulated in the form of its ester prodrug [LSF-linoleic acid (LA) prodrug] into biodegradable self-assembling polymeric micelles [LSF-LA PLM, size: 149.3 nm; polydispersity index: 0.209; critical micelle concentration (cmc); 5.95 µg/mL and Nagg: 14.82 at 10 cmc] of methoxypoly(ethylene glycol)-b-poly(carbonate-co-l-lactide) (mPEG-b-P(CB-co-LA)) block copolymer. LSF-LA PLM was found to be equally effective as the LSF-LA prodrug in cell culture studies in insulin-secreting MIN6 cells and showed excellent stability in simulating biological fluids and plasma. PK of LSF-LA PLM (10 mg/kg dose) revealed a significant improvement in oral bioavailability of LSF (74.86%; 3.3-fold increase in comparison to free LSF) and drastic reduction in the drug metabolism. Further, LSF-LA PLM showed a significant reduction in fasting glucose levels and increase in insulin levels by intraperitoneal as well oral routes in a streptozotocin (STZ)-induced T1D rat model. Production of inflammatory cytokines (TNF-α and IFN-γ) and different biochemical markers for liver and kidney functions were much reduced in diabetic animals after treatment with LSF-LA PLM. LSF-LA PLM-treated pancreatic sections showed minimal infiltration of CD4+ and CD8+ T-cells as indicated by hematoxylin/eosin staining and immunohistochemical analysis.

Self-assembling lisofylline-fatty acid conjugate for effective treatment of diabetes mellitus.

Lisofylline is an anti-inflammatory agent with proven anti-diabetic activity. Its high solubility and rapid metabolism results in poor bioavailability and short half-life, limiting its clinical utility. We have synthesized Lisofylline-Linoleic acid (LSF-LA) conjugate which self-assembled into micelles (156.9 nm; PDI 0.187; CMC 1 µg/mL; aggregation number 54) without any surfactant and showed enhanced cellular uptake. It protected MIN6 insulinoma cells from cytokine induced cell death and enhanced insulin production under inflammatory conditions. It also suppressed the proliferation of activated peripheral blood mononuclear cells and reduced the production of inflammatory cytokines, IFN-γ and TNF-α. LSF-LA micelles exhibited reduced protein binding, significantly higher half-life (5.7-fold) and higher apparent volume of distribution (5.3-fold) than free LSF. In T1D animals, reduced blood glucose levels were observed at a reduced dose (~15 mg/kg, once daily of LSF-LA micelles vs. 25 mg/kg, twice daily of free LSF) that was further confirmed by immunohistochemical analysis.

Influence of inflammatory disorders on pharmacokinetics of lisofylline in rats: implications for studies in humans.

1. Despite the number of favourable properties of lisofylline (LSF), clinical trials on this compound have not yielded the expected results yet. 2. The aims of this study were to evaluate the pharmacokinetics of LSF enantiomers in rats following intravenous, oral and subcutaneous administration of (±)-LSF and to assess the influence of experimental inflammatory disorders, such as multiple organ dysfunction syndrome and severe sepsis on LSF pharmacokinetics. 3. In addition, based on the results obtained an attempt was made to elucidate the possible reasons for the failure of LSF therapy in clinical trials carried out in patients with severe inflammatory disorders. 4. A subcutaneous route of (±)-LSF administration to rats is more favourable than an oral one due to a high bioavailability and a fast absorption of both LSF enantiomers. Pharmacokinetics of LSF in rats is significantly influenced by inflammatory diseases. Too low LSF serum levels might have been one of the reasons for clinical trial failures. A long-term i.v. infusion of LSF seems to be more effective compared to short-term multiple infusions that were used in clinical trials, as it may provide concentrations above IC50 for inhibition of both TNF-alpha release and cAMP degradation in serum for a longer period of time.

Simultaneous determination of pentoxifylline, metabolites M1 (lisofylline), M4 and M5, and caffeine in plasma and dried blood spots for pharmacokinetic studies in preterm infants and neonates.

Advances in bioanalytical methods are facilitating micro-volume and dried blood spot (DBS) analysis of drugs in biological matrices for pharmacokinetic studies in children and neonates. We sought to develop a UPLC-MS/MS assay for simultaneous measurement of caffeine, pentoxifylline (PTX) and three metabolites of PTX in both plasma and DBS. Caffeine, PTX, the metabolites M1 (lisofylline), M4 and M5, and the internal standards (caffeine-d9 and PTX-d6) were separated using a Waters Aquity T3 UPLC C18 column and gradient mobile phase (water-methanol-formic acid). Retention times for caffeine, M5, M4, PTX and M1 were 1.6, 1.7, 1.9, 2.0 and 2.1min, respectively, with a run time of 5min. The precision (≤10%) and accuracy (≤15%) across the concentration range 0.1-50mg/L for caffeine, PTX and the three metabolites in plasma and DBS were within accepted limits, as were the limits of quantification (100µg/L for caffeine and 10µg/L for PTX, M1, M4 and M5). Caffeine, PTX and the metabolites were stable in DBS for >34days at room and refrigerated temperatures. Plasma and DBS samples were obtained from 24 preterm infants recruited into a clinical pharmacokinetic study of PTX. Paired analysis indicated that DBS concentrations were 9% lower than concurrent plasma concentrations for caffeine, 7% lower for PTX (consistent with the blood:plasma ratio) and 13% lower for M1 (lisofylline). The validated UPLC-MS/MS method is suitable for micro-volume plasma and DBS analysis of caffeine, PTX and its metabolites for pharmacokinetic studies in paediatric patients.

Simultaneous estimation of lisofylline and pentoxifylline in rat plasma by high performance liquid chromatography-photodiode array detector and its application to pharmacokinetics in rat.

Lisofylline (LSF) is an anti-inflammatory and immunomodulatory agent with proven activity in serious infections associated with cancer chemotherapy, hyperoxia-induced acute lung injury, autoimmune disorders including type-1 diabetes (T1DM) and islet rejection after islet transplantation. It is also an active metabolite of another anti-inflammatory agent, Pentoxifylline (PTX). LSF bears immense therapeutic potential in multiple pharmacological activities and hence appropriate and accurate quantification of LSF is very important. Although a number of analytical methods for quantification of LSF and PTX have been reported for pharmacokinetics and metabolic studies, each of these have certain limitations in terms of large sample volume required, complex extraction procedure and/or use of highly sophisticated instruments like LC-MS/MS. The aim of current study is to develop a simple reversed-phase HPLC method in rat plasma for simultaneous determination of LSF and PTX with the major objective of ensuring minimum sample volume, ease of extraction, economy of analysis, selectivity and avoiding use of instruments like LC-MS/MS to ensure a widespread application of the method. A simple liquid-liquid extraction method using methylene chloride as extracting solvent was used for extracting LSF and PTX from rat plasma (200µL). Samples were then evaporated, reconstituted with mobile phase and injected into HPLC coupled with photo-diode detector (PDA). LSF, PTX and 3-isobutyl 1-methyl xanthine (IBMX, internal standard) were separated on Inertsil® ODS (C18) column (250×4.6mm, 5µm) with mobile phase consisting of A-methanol B-water (50:50v/v) run in isocratic mode at flow rate of 1mL/min for 15min and detection at 273nm. The method showed linearity in the concentration range of 50-5000ng/mL with LOD of 10ng/mL and LLOQ of 50ng/mL for both LSF and PTX. Weighted linear regression analysis was also performed on the calibration data. The mean absolute recoveries were found to be 80.47±3.44 and 80.89±3.73% for LSF and PTX respectively. The method was successfully applied for studying the pharmacokinetics of LSF and PTX after IV bolus administration at dose of 25mg/kg in Wistar rat. In conclusion, a simple, sensitive, accurate and precise reversed-phase HPLC-UV method was established for simultaneous determination of LSF and PTX in rat plasma.

Active Site Crowding of Cytochrome P450 3A4 as a Strategy To Alter Its Selectivity.

Substrate-promiscuous enzymes are a promising starting point for the development of versatile biocatalysts. In this study, human cytochrome P450 3A4, known for its ability to metabolise hundreds of drugs, was engineered to alter its regio- and stereoselectivity. Rational mutagenesis was used to introduce steric hindrance in a specific manner in the large active site of P450 3A4 and to favour oxidation at a more sterically accessible position on the substrate. Hydroxylation of a synthetic precursor of (R)-lisofylline, a compound under investigation for its anti-inflammatory properties, was chosen as a first proof-of-principle application of our protein engineering strategy. In a second example, increasing active site crowding led to an incremental shift in the selectivity of oxidation from an internal double bond to a terminal phenyl group in a derivative of theobromine. The same correlation between crowding and selectivity was found in a final case focused on the hydroxylation of the steroid sex hormone progesterone.

Expression of the p66Shc protein adaptor is regulated by the activator of transcription STAT4 in normal and chronic lymphocytic leukemia B cells.

p66Shc attenuates mitogenic, prosurvival and chemotactic signaling and promotes apoptosis in lymphocytes. Consistently, p66Shc deficiency contributes to the survival and trafficking abnormalities of chronic lymphocytic leukemia (CLL) B cells. The mechanism of p66shc silencing in CLL B cells is methylation-independent, at variance with other cancer cell types. Here we identify STAT4 as a novel transcriptional regulator of p66Shc in B cells. Chromatin immunoprecipitation and reporter gene assays showed that STAT4 binds to and activates the p66shc promoter. Silencing or overexpression of STAT4 resulted in a co-modulation of p66Shc. IL-12-dependent STAT4 activation caused a coordinate increase in STAT4 and p66Shc expression, which correlated with enhanced B cell apoptosis. Treatment with the STAT4 inhibitor lisofylline reverted partly this effect, suggesting that STAT4 phosphorylation is not essential for but enhances p66shc transcription. Additionally, we demonstrate that CLL B lymphocytes have a STAT4 expression defect which partly accounts for their p66Shc deficiency, as supported by reconstitution experiments. Finally, we show that p66Shc participates in a positive feedback loop to promote STAT4 expression. These results provide new insights into the mechanism of p66Shc expression in B cells and its defect in CLL, identifying the STAT4/IL-12 pathway as a potential therapeutic target in this neoplasia.

Pentoxifylline and its active metabolite lisofylline attenuate transforming growth factor ß1-induced asthmatic bronchial fibroblast-to-myofibroblast transition.

Bronchial asthma is characterized by persistent airway inflammation and airway wall remodeling. Among many different cells and growth factors triggering changes in bronchi structure, transforming growth factor ß1-induced fibroblast to myofibroblast transition is believed to be very important. The aim of this study was to evaluate whether theophylline (used in asthma therapy) and two other methylxanthines (pentoxifylline and its active metabolite lisofylline), may affect transforming growth factor ß1-induced fibroblast to myofibroblast transition in bronchial fibroblasts derived from asthmatic patients. We show here for the first time that selected methylxanthines effectively reduce transforming growth factor ß1-induced myofibroblast formation in asthmatic bronchial fibroblast populations. PTX was found to be the most effective methylxanthine. The number of differentiated myofibroblasts after PTX, LSF and THEO administration was reduced at least twofold. Studies on the use of methylxanthines opens a new perspective in the development of novel strategies in asthma therapy through their two-pronged, anti-inflammatory and anti-fibrotic action. In the future they can be considered as promising anti-fibrotic drugs.

A First-in-Patient, Multicenter, Double-Blind, 2-Arm, Placebo-Controlled, Randomized Safety and Tolerability Study of a Novel Oral Drug Candidate, CTP-499, in Chronic Kidney Disease.

The prevalence of chronic kidney disease (CKD) related to type 2 diabetes is increasing worldwide. In addition to standard of care, treatment with anti-inflammatory and antifibrotic agents such as CTP-499, a novel oral, multisubtype selective inhibitor of phosphodiesterases, may be important in CKD treatment. A phase 1b randomized, double-blind, placebo-controlled clinical trial of CTP-499 in CKD patients (25 active, 8 placebo) with an estimated glomerular filtration rate of 30-59 mL/min/1.73 m(2) was conducted to assess safety and tolerability. Secondary outcomes included pharmacokinetics and exploratory effects on inflammatory and hematology markers. Patients received 600 mg CTP-499 or matching placebo tablets orally once daily for 2 weeks, then twice daily for 2 additional weeks. CTP-499 was well tolerated with no serious or severe adverse events, or adverse events leading to discontinuation. CTP-499 was rapidly absorbed and produced acceptable interpatient variability. Of the 5 metabolites (M1-M5), M5 was the most abundant in plasma and urine. Exposure to CTP-499 and metabolites was higher in CKD patients than previously reported in healthy volunteers. No statistically significant differences were detected between the CTP-499- and placebo-treated groups for any of the biomarkers tested. This study provides data supporting further evaluation of CTP-499 in CKD patients.

Physiologically based modeling of lisofylline pharmacokinetics following intravenous administration in mice.

Lisofylline (LSF), is the R-(-) enantiomer of the metabolite M1 of pentoxifylline, and is currently under development for the treatment of type 1 diabetes. The aim of the study was to develop a physiologically based pharmacokinetic (PBPK) model of LSF in mice and to perform simulations in order to predict LSF concentrations in human serum and tissues following intravenous and oral administration. The concentrations of LSF in serum, brain, liver, kidneys, lungs, muscle, and gut were determined at different time points over 60 min by a chiral HPLC method with UV detection following a single intravenous dose of LSF to male CD-1 mice. A PBPK model was developed to describe serum pharmacokinetics and tissue distribution of LSF using ADAPT II software. All pharmacokinetic profiles were fitted simultaneously to obtain model parameters. The developed model characterized well LSF disposition in mice. The estimated intrinsic hepatic clearance was 5.427 ml/min and hepatic clearance calculated using the well-stirred model was 1.22 ml/min. The renal clearance of LSF was equal to zero. On scaling the model to humans, a good agreement was found between the predicted by the model and presented in literature serum LSF concentration-time profiles following an intravenous dose of 3 mg/kg. The predicted LSF concentrations in human tissues following oral administration were considerably lower despite the twofold higher dose used and may not be sufficient to exert a pharmacological effect. In conclusion, the mouse is a good model to study LSF pharmacokinetics following intravenous administration. The developed PBPK model may be useful to design future preclinical and clinical studies of this compound.

Effects of 1,7-substituted methylxanthine derivatives on LPS-stimulated expression of cytokines and chemokines in Raw 264.7 and HK-2 cells.

Chronic kidney diseases are based on uncontrolled immunological and inflammatory responses to pathophysiological renal circumstances such as glomerulonephritis, which is caused by immunological mechanisms of glomerular inflammation with increased production of renal pro-inflammatory cytokines. Pentoxifylline (PTX) exhibits anti-inflammatory properties by inhibiting cytokine and chemokine production through aggregation of erythrocytes and thrombocytes. We synthesized a series of 1,7-substituted methylxanthine derivatives by the Traube purine reaction, and the formation of purine ring was completed through nitrosation, a reduction of the nitroso to the amine by catalytic hydrogenation as derivatives of PTX. Then we studied biological activities such as renal anti-inflammatory effects of the synthesized compounds in the production of cytokines such as nitric oxide (NO), interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α) and of chemokines such as monocyte chemoattractant protein-1 and IL-8 in Raw 264.7 and HK-2 cells. Renal antiinflammatory activities of this novel series of N-1 and N-7-substituted methylxanthine showed that the N-7 methyl-group-substituted analogs (S7b) showed selective 61% and 77% inhibition of the production of NO and IL-8. The other replacement of the N-1-(CH2)4COCH3 group, as in the case of compound S6c, also showed an effective 50% and 77% inhibition of TNF-α and IL-8 production in LPS-stimulated Raw 264.7 and HK-2 cells.

Phosphodiesterase (PDE) inhibitor torbafylline (HWA 448) attenuates burn-induced rat skeletal muscle proteolysis through the PDE4/cAMP/EPAC/PI3K/Akt pathway.

Treatment of rats after burn-injury with the cyclic AMP phosphodiesterase (PDE) inhibitor, torbafylline (also known as HWA 448) significantly reversed changes in rat skeletal muscle proteolysis, PDE4 activity, cAMP concentrations and mRNA expression of TNFα, IL-6, ubiquitin and E3 ligases. Torbafylline also attenuated muscle proteolysis during in vitro incubation, and this effect was blocked by the inhibitor Rp-cAMPS. Moreover, torbafylline significantly increased phospho-Akt levels, and normalized downregulated phospho-FOXO1 and phospho-4E-BP1 in muscle of burn rats. Similarly, torbafylline also normalized phosphorylation levels of Akt and its downstream elements in TNFα+IFNγ treated C2C12 myotubes. Torbafylline enhanced protein levels of exchange protein directly activated by cAMP (Epac) both in skeletal muscle of burn rats and in TNFα+IFNγ treated C2C12 myotubes. Pretreatment with a specific antagonist of PI3K or Epac significantly reversed the inhibitory effects of torbafylline on TNFα+IFNγ-induced MAFbx mRNA expression and protein breakdown in C2C12 myotubes. Torbafylline inhibits burn-induced muscle proteolysis by activating multiple pathways through PDE4/cAMP/Epac/PI3K/Akt.

Quantitative analyses of CTP-499 and five major metabolites by core-structure analysis.

CTP-499 is a novel oral multi-subtype selective inhibitor of PDEs that is currently in clinical testing, in combination with angiotensin modulators, as a potentially first-in-class treatment for diabetic kidney disease. The compound was discovered and developed by using Concert's proprietary DCE Platform(®) in which deuterium was incorporated at select positions of 1-((S)-5-hydroxyhexyl)-3,7-dimethylxanthine (HDX). CTP-499 metabolizes to five major metabolites: C-21256, D-M2, D-M3, D-M4 and M5, of which all contains deuterium except M5. During in vivo metabolism, however, H/D exchange takes place. As a result, each analyte, except M5, has multiple molecular masses. To accurately quantify the analytes, we developed an LC-MS/MS method focusing on the core structures of the molecules, termed "core-structure analyses". The core-structure analyses method was then validated under GLP guidance in dog, rat and rabbit plasma, with a sample volume of 50 µL. Results demonstrated that this approach accurately quantifies each of the six analytes despite partial exchange of deuterium with hydrogen atoms in the in vivo samples. The validation parameters included accuracy, precision, sensitivity, stability, dilution integrity, hemolysis, matrix effect, selectivity, and recovery. Acceptable intra-run and inter-run assay precision (%CV ≤ 5.5%) and accuracy (90.1-106.7%) were achieved over a linear range of 10-5,000 ng/mL of each analyte. Various stability tests, including bench-top, freeze/thaw, stock solution, and long-term storage, were also performed. All stability results met acceptance criteria. The robustness of the methods was demonstrated by the incurred sample reproducibility (ISR) tests. After validation, the method was successfully used in support of multiple toxicological studies of CTP-499.

In vitro effect of pentoxifylline and lisofylline on deformability and aggregation of red blood cells from healthy subjects and patients with chronic venous disease.

Purpose. The aim of the study was to assess the in vitro potency of pentoxifylline (PTX) and one of its most active metabolites lisofylline (LSF) to improve rheological properties of red blood cells (RBC) from healthy individuals and patients with chronic venous disease (CVD). Additionally, the study aimed to compare the effects of PTX and LSF on RBC deformability and aggregation. Methods. Blood samples were collected from healthy volunteers (antecubital vein) and from CVD patients (varicose and antecubital vein). Deformability and aggregation of RBC were assessed using Laser-assisted Optical Rotational Cell Analyser (LORCA). Results. PTX and LSF increased RBC elongation significantly. Additionally, RBC incubation with PTX resulted in a marked decrease in RBC aggregation. PTX reduced the tendency towards the formation of RBC aggregates and of their stability. The beneficial effect of PTX on RBC aggregation was most apparent for those cells whose aggregation tendency and aggregate stability was the greatest. Conclusions. In vitro addition of PTX or LSF effectively increased deformability of RBC from healthy donors and patients with CVD. Thus, LSF may contribute to the in vivo hemorheological effects of pentoxifylline. On the other hand, there was no significant effect of LSF on aggregation of RBC in vitro. Hence, LSF has no contribution to this particular effect of PTX. Additionally, the present study demonstrated the use of RBC with impaired deformability and aggregation for the evaluation of in vitro rheological activity of xenobiotics.

Macrolide antibiotics and survival in patients with acute lung injury.

BACKGROUND: Animal models suggest that immunomodulatory properties of macrolide antibiotics have therapeutic value for patients with acute lung injury (ALI). We investigated the association between receipt of macrolide antibiotics and clinical outcomes in patients with ALI. METHODS: Secondary analysis of multicenter, randomized controlled trial data from the Acute Respiratory Distress Syndrome Network Lisofylline and Respiratory Management of Acute Lung Injury Trial, which collected detailed data regarding antibiotic use among participants with ALI. RESULTS: Forty-seven of 235 participants (20%) received a macrolide antibiotic within 24 h of trial enrollment. Among patients who received a macrolide, erythromycin was the most common (57%), followed by azithromycin (40%). The median duration of macrolide use after study enrollment was 4 days (interquartile range, 2-8 days). Eleven of the 47 (23%) patients who received macrolides died, compared with 67 of the 188 (36%) who did not receive a macrolide (P = .11). Participants administered macrolides were more likely to have pneumonia as an ALI risk factor, were less likely to have nonpulmonary sepsis or to be randomized to low tidal volume ventilation, and had a shorter length of stay prior to trial enrollment. After adjusting for potentially confounding covariates, use of macrolide was associated with lower 180-day mortality (hazard ratio [HR], 0.46; 95% CI, 0.23-0.92; P = .028) and shorter time to successful discontinuation of mechanical ventilation (HR, 1.93; 95% CI, 1.18-3.17; P = .009). In contrast, fluoroquinolone (n = 90) and cephalosporin antibiotics (n = 93) were not associated with improved outcomes. CONCLUSIONS: Receipt of macrolide antibiotics was associated with improved outcomes in patients with ALI.