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ABSTRACT: OBJECTIVES: Chronic azithromycin therapy has been associated with improved clinical outcomes in patients with cystic fibrosis (CF) who are chronically infected with Pseudomonas aeruginosa. We have previously demonstrated that azithromycin polarizes macrophages towards an alternatively activated phenotype, thereby blunting inflammation associated with infection. Because this phenotype is pro-fibrotic, it is important to evaluate azithromycin's consequential effects upon fibroblast function and extracellular matrix (ECM) protein production. METHODS: We co-cultured macrophages and fibroblasts together and stimulated them by adding P. aeruginosa or lipopolysaccharide to assess the ability of azithromycin to alter the macrophage phenotype, along with the impact exerted upon the production of fibronectin and other effectors that govern tissue remodelling, including transforming growth factor β (TGFβ), matrix metalloproteinase-9 (MMP-9) and arginase. We supported these studies by evaluating the impact of azithromycin treatment on these proteins in a mouse model of P. aeruginosa infection. RESULTS: Azithromycin increased arginase expression in vitro, as well as the activation of latent TGFβ, consistent with polarization to the alternative macrophage phenotype. While the drug increased fibronectin concentrations after stimulation in vitro, secretion of the ECM-degrading enzyme MMP-9 was also increased. Neutralization of active TGFβ resulted in the ablation of azithromycin's ability to increase fibronectin concentrations, but did not alter its ability to increase MMP-9 expression. In P. aeruginosa-infected mice, azithromycin significantly decreased MMP-9 and fibronectin concentrations in the alveolar space compared with non-treated, infected controls. CONCLUSIONS: Our results suggest that azithromycin's effect on MMP-9 is regulated independently of TGFβ activity. Additionally, the beneficial effects of azithromycin may be partially due to effects on homeostasis in which ECM-degrading mediators like MMP-9 are up-regulated early after infection. This may impact the damaging effects of inflammation that lead to fibrosis in this patient population.
Journal of Antimicrobial Chemotherapy 12/2012; · 5.07 Impact Factor
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ABSTRACT: The use of a continuous infusion of a β-lactam antibiotic in combination with high-dose, extended-interval amino-glycoside therapy for eradication of Pseudomonas aeruginosa in an adult patient with cystic fibrosis (CF) is reported.
Testing of an expectorated sputum sample taken during routine evaluation of a 32-year-old woman with CF isolated P. aeruginosa; the patient's medical record indicated no prior episodes of P. aeruginosa colonization. In an initial attempt to eradicate the organism, the woman received outpatient therapy with oral ciprofloxacin twice daily combined with an aminoglycoside (tobramycin solution) by nebulization twice daily. After a culture four weeks later again isolated P. aeruginosa, the patient was hospitalized, and i.v. antimicrobial therapy was initiated. The inpatient treatment regimen consisted of continuous-infusion cefepime 6 g (100 mg/kg/24 hr) and i.v. tobramycin 700 mg (12 mg/kg/24 hr), with both drugs administered via a peripherally inserted central catheter, for two weeks. A bronchoalveolar lavage fluid culture performed two months after completion of the i.v. antimicrobial regimen, as well as several sputum cultures obtained during the subsequent three years, tested negative for P. aeruginosa.
The administration of continuous-infusion cefepime and high-dose, extended-interval tobramycin led to the successful eradication of P. aeruginosa in an adult patient with CF.
American journal of health-system pharmacy: AJHP: official journal of the American Society of Health-System Pharmacists 02/2011; 68(4):319-22. · 2.10 Impact Factor
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ABSTRACT: Bronchopulmonary dysplasia (BPD) results from prematurity and surfactant deficiency with contributing factors from barotrauma, volutrauma, and oxygen toxicity from supportive mechanical ventilation care and infection. These factors result in chronic inflammation with recurring cycles of lung damage and repair that impair alveolarisation and vascularisation in developing infant lungs. With advancement in the understanding of its pathophysiology and resulting therapy, BPD has evolved into a different disorder which has been coined the 'new' BPD. As these patients age, primary care physicians need to understand the impact on pulmonary function. This discussion reviews the pulmonary function outcomes resulting from BPD through later childhood and young adulthood.
Primary care respiratory journal: journal of the General Practice Airways Group 02/2011; 20(2):128-33.
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ABSTRACT: The presence of resistant pathogens in the lower airways of patients with cystic fibrosis (CF) is not an absolute contraindication for lung transplantation. We describe a case in which a patient with CF died as a result of an anastomotic dehiscence, ischemia, and infection with linezolid-resistant methicillin-resistant Staphylococcus aureus. We review infection issues during the post-lung-transplant period and related anastomotic dehiscence in CF.
Respiratory care 12/2010; 55(12):1746-50. · 2.01 Impact Factor
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ABSTRACT: Allergic bronchopulmonary aspergillosis (ABPA) is a complex hypersensitivity reaction to Aspergillus fumigatus that occur frequently in patients with cystic fibrosis (CF). Recurrent episodes of bronchial obstruction, inflammation, and mucoid impaction occur in ABPA and results in bronchiectasis, fibrosis, and respiratory failure. The treatment of ABPA includes corticosteroids to reduce the acute inflammation and intraconazole to reduce the fungal colonization load in order to reduce lung injury. This case discusses the successful use of aerosolized amphotericin B for the treatment of ABPA in a 14-year-old patient with CF listed for lung transplant. The patient required fewer hospitalizations, and both oral corticosteroids and anti-fungal therapy were eventually stopped.
Pediatric Pulmonology 11/2010; 45(11):1145-8. · 2.53 Impact Factor
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ABSTRACT: Phytosterol supplements lower low-density lipoprotein (LDL) cholesterol, but accumulate in vascular lesions of patients and limit the anti-atherosclerotic effects of LDL lowering in apolipoprotein E (Apo E)-deficient mice, suggesting that the cholesterol-lowering benefit of phytosterol supplementation may not be fully realized. Individual phytosterols have cell-type specific effects that may be either beneficial or deleterious with respect to atherosclerosis, but little is known concerning their effects on macrophage function. The effects of phytosterols on ABCA1 and ABCG1 abundance, cholesterol efflux and inflammatory cytokine secretion were determined in cultured macrophage foam cells. Among the commonly consumed phytosterols, stigmasterol increased expression of ABCA1 and ABCG1 and increased efflux of cholesterol to apolipoprotein (Apo) AI and high-density lipoprotein (HDL). Campesterol and sitosterol had no effect on ABCA1 or ABCG1 levels. Sitosterol had no effect on cholesterol efflux to Apo AI or HDL, whereas campesterol had a modest but significant reduction in cholesterol efflux to HDL in THP-1 macrophages. Whereas stigmasterol blunted aggregated LDL (agLDL) induced increases in tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β secretion, sitosterol exacerbated these effects. The presence of campesterol had no effect on agLDL-induced inflammatory cytokine secretion from THP-1 macrophages. In conclusion, the presence of stigmasterol in modified lipoproteins promoted cholesterol efflux and suppressed inflammatory cytokine secretion in response to lipid loading in macrophage foam cells. While campesterol was largely inert, the presence of sitosterol increased the proinflammatory cytokine secretion.
The Journal of nutritional biochemistry 11/2010; 22(8):777-83. · 4.29 Impact Factor
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ABSTRACT: Chronic airway inflammation characterizes patients with cystic fibrosis (CF). The role of alternative macrophage activation in this disease course is unknown.
We evaluated markers of alternative and classical macrophage activation in the lungs of patients with CF and evaluated these characteristics in the context of Pseudomonas aeruginosa (PA) infection, immunomodulatory drug therapy and pulmonary function.
Bronchoalveolar lavage or spontaneously expectorated sputum samples were collected from 48 CF patients. Clinical data were related to macrophage surface expression of mannose receptor (MR) (up-regulated in alternatively activated macrophages) and TLR4 (up-regulated in classically activated macrophages). Also, the activity of the alternatively activated macrophage effector molecule arginase was compared among patient groups, and pro- and anti-inflammatory cytokines produced by alternatively and classically activated macrophages were measured.
There were significant differences between PA-infected and -uninfected patients in several clinical measurements. PA-infected patients exhibited increased use of azithromycin, up-regulation of MR on CD11b+ cells and increased arginase activity in their lung samples, and had a strong inverse relationship between MR and arginase activity to FEV(1). Upon further analysis, PA-infected patients who were treated with azithromycin had the highest arginase activity and the highest number of macrophages that were MR+TLR4-, and both of these markers were inversely related to the FEV(1).
Our findings suggest an increase in both MR and arginase expression as pulmonary function declines in PA-infected patients with CF. These markers of an alternatively activated macrophage phenotype give cause for future study to define the function of macrophage activation states in the CF lung.
Journal of cystic fibrosis: official journal of the European Cystic Fibrosis Society 09/2010; 9(5):314-22. · 3.19 Impact Factor
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ABSTRACT: Infection with mucoid strains of Pseudomonas aeruginosa in chronic inflammatory diseases of the airway is difficult to eradicate and can cause excessive inflammation. The roles of alternatively activated and regulatory subsets of macrophages in this pathophysiological process are not well characterized. We previously demonstrated that azithromycin induces an alternatively activated macrophage-like phenotype in vitro. In the present study, we tested whether azithromycin affects the macrophage activation status and migration in the lungs of P. aeruginosa-infected mice. C57BL/6 mice received daily doses of oral azithromycin and were infected intratracheally with a mucoid strain of P. aeruginosa. The properties of macrophage activation, immune cell infiltration, and markers of pulmonary inflammation in the lung interstitial and alveolar compartments were evaluated postinfection. Markers of alternative macrophage activation were induced by azithromycin treatment, including the surface expression of the mannose receptor, the upregulation of arginase 1, and a decrease in the production of proinflammatory cytokines. Additionally, azithromycin increased the number of CD11b(+) monocytes and CD4(+) T cells that infiltrated the alveolar compartment. A predominant subset of CD11b(+) cells was Gr-1 positive (Gr-1(+)), indicative of a subset of cells that has been shown to be immunoregulatory. These differences corresponded to decreases in neutrophil influx into the lung parenchyma and alteration of the characteristics of peribronchiolar inflammation without any change in the clearance of the organism. These results suggest that the immunomodulatory effects of azithromycin are associated with the induction of alternative and regulatory macrophage activation characteristics and alteration of cellular compartmentalization during infection.
Antimicrobial Agents and Chemotherapy 03/2010; 54(6):2437-47. · 4.84 Impact Factor
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ABSTRACT: Lung transplantation is the only life-prolonging therapy available for cystic fibrosis (CF) patients with end-stage lung disease. The presence of pathogens in the airways of CF patients prior to transplantation is the major risk factor for infection in the post-transplantation period, with methicillin-resistant Staphylococcus aureus (MRSA) having a growing impact. Aerosolized vancomycin has been used successfully in the treatment of MRSA in the CF population but its use after lung transplantation has not been previously reported. We report the case of a lung transplant recipient who was successfully treated for MRSA infection with aerosolized vancomycin.
Respirology 11/2009; 15(1):184-6. · 2.42 Impact Factor
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ABSTRACT: Bronchopulmonary dysplasia (BPD) refers to a heterogeneous group of lung disorders in infants that is commonly associated with prematurity and surfactant deficiency. BPD results from the complex interplay between impairments in the premature lung such as surfactant deficiency, perinatal insults such as infection, and damage resulting from supportive care of the infant due to barotrauma or volutrauma from mechanical ventilation and oxygen toxicity from supplemental oxygen administration. These factors result in chronic inflammation in the infant lung with recurring cycles of lung damage and repair that may impair alveolarization and vascularization in the developing lungs. As our insight in how to treat BPD improves along with the ability to do so with developing technology and therapies, the underlying pathogenesis will also change. The term 'new' BPD is now commonly used, to describe the changes seen in the post-surfactant era. This discussion reviews the pathogenesis of BPD according to the current medical literature.
Respiration 09/2009; 79(5):425-36. · 2.26 Impact Factor
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ABSTRACT: Inquilinus limosus is a alpha-proteobacterium that has been recently isolate in the airways of cystic fibrosis (CF) patients. We report the isolation of a mucoid strain of I. limosus from the sputum of a 20-year-old male patient with CF over 1 year that was associated with the clinical, spirometric, and radiographic decline in a previously healthy patient.
Pediatric Pulmonology 06/2009; 44(6):619-21. · 2.53 Impact Factor
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ABSTRACT: To determine if exposure to trimethoprim-sulfamethoxazole (TMP-SMX) causes a defect in peripheral B-cell function among patients with the human immunodeficiency virus (HIV) who are receiving zidovudine antiretroviral therapy.
Prospective, single-center, single-group, case-crossover design with a 4-week exposure period.
University-affiliated infectious diseases outpatient clinic.
Fourteen HIV-infected adult men receiving zidovudine, who had CD4(+) cell counts above 350 cells/mm(3) and undetectable viral loads.
Patients were administered a 28-day course of TMP 160 mg-SMX 800 mg/day (one double-strength tablet/day). Peripheral blood mononuclear cells (PBMCs) were obtained and isolated before and after exposure to TMP-SMX. Cells were cultured ex vivo with three mitogens of differing immunologic properties: pokeweed mitogen ([PWM] T-cell-dependent B-cell mitogen), Staphylococcus aureus Cowan ([SAC] T-cell-independent B-cell mitogen), and phytohemagglutinin A ([PHA] T-cell mitogen). Functionality of the B and T lymphocytes was then assessed.
Proliferative capacity, cytokine secretion, and antibody production were measured and compared before and after TMP-SMX exposure. Reduced proliferative capacities of both PBMC and B cells stimulated with mitogens were observed at the 3-day culture time point in response to PWM, PHA, and SAC (p=0.029, 0.028, and 0.026, respectively). Proliferative capacity at day 7 of culture was not significantly different for any condition examined. Cytokine production was not altered by combination drug exposure after 10 days of culture when cells were stimulated with either PWM or PHA. Although antibody responses to PWM and PHA were similar, total immunoglobulin G concentration was lower in cells stimulated with SAC in samples obtained after TMP-SMX regimen completion compared with those obtained before exposure (p=0.005).
Although these data were affected by limitations in power and study design, they suggest that peripheral B-lymphocyte function is altered as a result of TMP-SMX exposure in HIV-infected patients concurrently receiving zidovudine. Further study of this effect is warranted.
Pharmacotherapy 05/2009; 29(4):373-82. · 2.90 Impact Factor
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ABSTRACT: To investigate the in vitro effects of azithromycin on macrophage phenotype. Utilizing a mouse macrophage cell line (J774), we examined the effect of azithromycin on the properties that define classical macrophage activation (M1) and alternative macrophage activation (M2).
J774 cells were cultured in the presence of azithromycin and stimulated with classical activation [interferon-gamma (IFNgamma)] and alternative activation [interleukin (IL)-4 and IL-13] cytokines along with lipopolysaccharide (LPS). Macrophages were analysed for inflammatory cytokine production, surface receptor expression, inducible nitric oxide synthase (iNOS) protein expression and arginase activity.
Azithromycin altered the overall macrophage phenotype. Azithromycin-treated J774 macrophages demonstrated a significantly reduced production of the pro-inflammatory cytokines IL-12 and IL-6, increased production of the anti-inflammatory cytokine IL-10 and decreased the ratio of IL-12 to IL-10 by 60%. Receptor expression indicative of the M2 phenotype (mannose receptor and CD23) was increased, and receptor expression typically up-regulated in M1 cells (CCR7) was inhibited. The presence of azithromycin increased arginase (M2 effector molecule) activity 10-fold in cells stimulated with IFNgamma and LPS, and iNOS protein (M1 effector molecule) concentrations were attenuated by the drug.
These data provide evidence that azithromycin affects the inflammatory process at the level of the macrophage and shifts macrophage polarization towards the alternatively activated phenotype. This recently defined M2 phenotype has been described in conditions in which pulmonary inflammation and fibrosis are major determinants of clinical outcome, but the concept of antibiotics altering macrophage phenotype has not yet been critically evaluated.
Journal of Antimicrobial Chemotherapy 04/2008; 61(3):554-60. · 5.07 Impact Factor
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ABSTRACT: To determine as proof of principle the effect of combination exposure to zidovudine plus trimethoprim-sulfamethoxazole (TMP-SMX) on humoral immune responses to influenza vaccination in patients with human immunodeficiency virus (HIV).
Prospective, open-label trial.
University-affiliated infectious diseases outpatient clinic.
Twenty-three HIV-infected adults receiving antiretroviral therapy, with CD4+ cell counts greater than 350 cells/mm3 and undetectable viral loads.
Patients were assigned to one of four treatment groups: zidovudine (6 patients), TMP-SMX (7), zidovudine plus TMP-SMX (5), or neither drug (5); TMP-SMX was given as a 28-day course. Patients were subsequently immunized with the yearly influenza vaccine, and humoral responses were compared among groups 20-24 days after vaccination.
Antibody responses to influenza A and B were measured, and total and activated T and B cell percentages in the peripheral blood were determined. Mean influenza B-specific serum immunoglobulin (Ig)G titers were significantly lower in patients receiving TMP-SMX alone (0.98 +/- 0.60 reference value, p=0.010) or the combination of zidovudine plus TMP-SMX (0.73 +/- 0.29 reference value, p=0.003) compared with those receiving neither drug (1.95 +/- 0.38 reference value). This corresponded to a significantly lower percentage of patients in the combination group that achieved immunoprotective titers to influenza B compared with the group who received neither drug (control group; 20% vs 100%, p=0.048). In addition, the relationship between serum IgG titer and CD4+ cell count was statistically significantly different for patients exposed to zidovudine plus TMP-SMX versus control patients for both influenza A and B (F statistics 8.72 and 11.70, respectively, compared with critical F value 7.26 for p<0.025). Likewise, the relationship between influenza B serum IgG and CD4+ cell count was different among patients who received TMP-SMX versus those who did not receive TMP-SMX (F statistic 5.95 compared with critical F value 4.56 for p<0.025). No significant differences were observed among T and B cell percentages in the blood.
Combination exposure to zidovudine plus TMP-SMX causes a clinically significant suppression of humoral immune responses to influenza vaccination in HIV-infected patients.
Pharmacotherapy 07/2007; 27(7):937-47. · 2.90 Impact Factor
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ABSTRACT: We have previously shown that zidovudine plus sulfamethoxazole-trimethoprim exposure decreases immune cell populations in the bone marrow of healthy mice by inducing apoptosis. The hypothesis of the current work was that this toxicity would have an adverse impact on the immune response. To determine this, BALB/c mice were treated with zidovudine, sulfamethoxazole-trimethoprim, the combination of both drugs, or vehicle only (control) via oral gavage for 21 days. On day 4 after dosing completion, the mice were infected intratracheally with 1x10(7) Pneumocystis murina organisms. Immune cell populations (in lung digest, bronchoalveolar lavage fluid, tracheobronchial lymph node, and bone marrow samples), the lung Pneumocystis burden, and serum Pneumocystis-specific antibody titers were determined at days 6, 10, and 20 postinfection. While total bone marrow cellularity was recovered by day 6 postinfection in the combination exposure group, B-cell numbers did not recover until 10 days postinfection, primarily due to the persistent depletion of the late pre-B-cell phenotype. The numbers of CD4+ and CD8+ T cells, as well as the numbers of total B cells and activated B cells in tracheobronchial lymph nodes, were decreased at days 10 and 20 as a result of zidovudine plus sulfamethoxazole-trimethoprim exposure compared to the numbers in the control group. No significant differences in lung lavage or lung digest cell populations were observed. There was a trend of a delay in Pneumocystis clearance in the combination treatment group, and Pneumocystis-specific serum immunoglobulin G titers were reduced at day 20 postinfection. Together, these data indicate that the combination of zidovudine and sulfamethoxazole-trimethoprim adversely affects the humoral immune response to Pneumocystis.
Clinical and Vaccine Immunology 03/2006; 13(2):193-201. · 2.55 Impact Factor
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ABSTRACT: Sulfamethoxazole-trimethoprim and zidovudine (AZT), drugs used often in combination in patients infected with HIV, were investigated for their effects on B cell development in a mouse model. BALB/c mice were randomized to receive oral doses of AZT, sulfamethoxazole-trimethoprim, or the combination via oral gavage for up to 28 days. Immune cell populations in the spleen, lung, and peripheral blood were examined, and toxicity to B lineage subtypes in the bone marrow was investigated by phenotypic analysis via flow cytometry. Pre-pro-B, pro-B, early pre-B, and late pre-B cells were assayed for apoptosis and analyzed for cell cycle profile. Total as well as B cell splenic and bone marrow cellularities were significantly decreased by using the drugs concomitantly, while B cell populations in the lungs and percentage in the peripheral blood were not affected. Combination therapy caused significant increases in apoptosis in B cells and granulocytes in the bone marrow, with the late pre-B cell population being the most depleted. The proliferative expansion and differentiation of early pre-B cells (B220+/CD43+/BP-1+/HSA+) to the late pre-B cell (B220+/CD43-/IgM-) stage was blocked, with early pre-B cells accumulating in the proliferative phases of the cell cycle. This apoptosis increase is likely due to elevated blood sulfamethoxazole concentrations that were observed in mice also receiving AZT. Concurrent sub-chronic administration of AZT and sulfamethoxazole-trimethoprim adversely affected B lymphocyte development in mouse bone marrow.
International Immunopharmacology 01/2006; 5(13-14):1881-94. · 2.38 Impact Factor
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ABSTRACT: Recurrent acute pancreatitis associated with metronidazole developed in a 49-year-old woman who was taking the drug as treatment for vaginal trichomoniasis. The lack of alternative effective therapies for trichomoniasis governed the decision to rechallenge the patient with metronidazole despite a vague history of this reaction on a previous occasion. Six reports of this reaction are found in the literature. The patient was admitted to the hospital 12 hours after taking a single dose of metronidazole. Severe epigastric pain and elevated amylase and lipase concentrations led to the diagnosis of acute pancreatitis, although results of an abdominal ultrasound were unremarkable. The patient made a full recovery. Although this reaction occurs infrequently, this case report illustrates the need to develop additional therapies for treatment of trichomoniasis.
Pharmacotherapy 12/2002; 22(11):1508-10. · 2.90 Impact Factor
