Dataset Information

Phosphodiesterase-4 inhibition combined with isoniazid treatment of rabbits with pulmonary tuberculosis reduces macrophage activation and lung pathology.

ABSTRACT: Tuberculosis (TB) is responsible for significant morbidity and mortality worldwide. Even after successful microbiological cure of TB, many patients are left with residual pulmonary damage that can lead to chronic respiratory impairment and greater risk of additional TB episodes due to reinfection with Mycobacterium tuberculosis. Elevated levels of the proinflammatory cytokine tumor necrosis factor-? and several other markers of inflammation, together with expression of matrix metalloproteinases, have been associated with increased risk of pulmonary fibrosis, tissue damage, and poor treatment outcomes in TB patients. In this study, we used a rabbit model of pulmonary TB to evaluate the impact of adjunctive immune modulation, using a phosphodiesterase-4 inhibitor that dampens the innate immune response, on the outcome of treatment with the antibiotic isoniazid. Our data show that cotreatment of M. tuberculosis infected rabbits with the phosphodiesterase-4 inhibitor CC-3052 plus isoniazid significantly reduced the extent of immune pathogenesis, compared with antibiotic alone, as determined by histologic analysis of infected tissues and the expression of genes involved in inflammation, fibrosis, and wound healing in the lungs. Combined treatment with an antibiotic and CC-3052 not only lessened disease but also improved bacterial clearance from the lungs. These findings support the potential for adjunctive immune modulation to improve the treatment of pulmonary TB and reduce the risk of chronic respiratory impairment.

SUBMITTER: Subbian S

PROVIDER: S-EPMC3123788 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Phosphodiesterase-4 inhibition combined with isoniazid treatment of rabbits with pulmonary tuberculosis reduces macrophage activation and lung pathology.

Subbian Selvakumar S Tsenova Liana L O'Brien Paul P Yang Guibin G Koo Mi-Sun MS Peixoto Blas B Fallows Dorothy D Zeldis Jerome B JB Muller George G Kaplan Gilla G

The American journal of pathology 20110507 1

Tuberculosis (TB) is responsible for significant morbidity and mortality worldwide. Even after successful microbiological cure of TB, many patients are left with residual pulmonary damage that can lead to chronic respiratory impairment and greater risk of additional TB episodes due to reinfection with Mycobacterium tuberculosis. Elevated levels of the proinflammatory cytokine tumor necrosis factor-α and several other markers of inflammation, together with expression of matrix metalloproteinases, ...[more]

PMID: 21703411

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Project description:Tuberculosis (TB) treatment is hampered by the long duration of antibiotic therapy required to achieve cure. This indolent response has been partly attributed to the ability of subpopulations of less metabolically active Mycobacterium tuberculosis (Mtb) to withstand killing by current anti-TB drugs. We have used immune modulation with a phosphodiesterase-4 (PDE4) inhibitor, CC-3052, that reduces tumor necrosis factor alpha (TNF-?) production by increasing intracellular cAMP in macrophages, to examine the crosstalk between host and pathogen in rabbits with pulmonary TB during treatment with isoniazid (INH). Based on DNA microarray, changes in host gene expression during CC-3052 treatment of Mtb infected rabbits support a link between PDE4 inhibition and specific down-regulation of the innate immune response. The overall pattern of host gene expression in the lungs of infected rabbits treated with CC-3052, compared to untreated rabbits, was similar to that described in vitro in resting Mtb infected macrophages, suggesting suboptimal macrophage activation. These alterations in host immunity were associated with corresponding down-regulation of a number of Mtb genes that have been associated with a metabolic shift towards dormancy. Moreover, treatment with CC-3052 and INH resulted in reduced expression of those genes associated with the bacterial response to INH. Importantly, CC-3052 treatment of infected rabbits was associated with reduced ability of Mtb to withstand INH killing, shown by improved bacillary clearance, from the lungs of co-treated animals compared to rabbits treated with INH alone. The results of our study suggest that changes in Mtb gene expression, in response to changes in the host immune response, can alter the responsiveness of the bacteria to antimicrobial agents. These findings provide a basis for exploring the potential use of adjunctive immune modulation with PDE4 inhibitors to enhance the efficacy of existing anti-TB treatment.

Project description:The blood concentration of isoniazid (INH) is evidently affected by polymorphisms in N-acetyltransferase 2 (NAT2), an enzyme that is primarily responsible for the trimodal (i.e., fast, intermediate, and slow) INH elimination. The pharmacokinetic (PK) variability, driven largely by NAT2 activity, creates a challenge for the deployment of a uniform INH dosage in tuberculosis (TB) patients. Although acetylator-specific INH dosing has long been suggested, well-recognized dosages according to acetylator status remain elusive. In this study, 175 blood samples were collected from 89 pulmonary TB patients within 0.5 to 6 h after morning INH administration. According to their NAT2 genotypes, 32 (36.0%), 38 (42.7%), and 19 (21.3%) were fast, intermediate, and slow acetylators, respectively. The plasma INH concentration was detected by liquid chromatography-tandem mass spectrometry. Population pharmacokinetic (PPK) analysis was conducted using NONMEM and R software. A two-compartment model with first-order absorption and elimination well described the PK parameters of isoniazid. Body weight and acetylator status significantly affected the INH clearance rate. The dosage simulation targeting three indicators, including the well-recognized efficacy-safety indicator maximum concentration in serum (C max; 3 to 6??g/ml), the reported area under the concentration-time curve from 0 h to infinity (AUC0-?; ?10.52??g·h/ml), and the 2-h INH serum concentrations (?2.19??g/ml), was associated with the strongest early bactericidal activity. The optimal dosages targeting the different indicators varied from 700 to 900?mg/day, 500 to 600?mg/day, and 300?mg/day for the rapid, intermediate, and slow acetylators, respectively. Furthermore, a PPK model for isoniazid among Chinese tuberculosis patients was established for the first time and suggested doses of approximately 800?mg/day, 500?mg/day, and 300?mg/day for fast, intermediate, and slow acetylators, respectively, after a trade-off between efficacy and the occurrence of side effects.

Dataset Information

Phosphodiesterase-4 inhibition combined with isoniazid treatment of rabbits with pulmonary tuberculosis reduces macrophage activation and lung pathology.

Publications

Phosphodiesterase-4 inhibition combined with isoniazid treatment of rabbits with pulmonary tuberculosis reduces macrophage activation and lung pathology.

Similar Datasets

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