Article

Phosphodiesterase-4 Inhibition Combined with Isoniazid Treatment of Rabbits with Pulmonary Tuberculosis Reduces Macrophage Activation and Lung Pathology

Laboratory of Mycobacterial Immunity and Pathogenesis, The Public Health Research Institute at the University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, USA.
American Journal Of Pathology (Impact Factor: 4.6). 07/2011; 179(1):289-301. DOI: 10.1016/j.ajpath.2011.03.039
Source: PubMed

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-α 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.

2 Followers
 · 
135 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tuberculosis (TB) is a major health problem requiring sustained immunity to inhibit Mycobacterium tuberculosis growth and appropriate antimicrobial therapy to prevent dissemination and drug resistance. Cell-mediated immune responses to M. tuberculosis involve the activation of cytokines such as Tumor Necrosis Factor (TNF) which is critical for granuloma formation and host resistance against TB. TNF inhibition, used as therapy for the treatment of inflammatory diseases, disrupts granuloma allowing replication of mycobacteria which may increase the efficacy of TB chemotherapy. To test this hypothesis mice infected with M. tuberculosis were treated with isoniazid (INH) and rifampicin (RMP) in the presence or absence of Enbrel, a soluble TNF receptor antagonist during three phases of M. tuberculosis infection. Inhibition of TNF with Enbrel augmented the efficacy of TB chemotherapy as shown by enhanced mycobacterial clearance from the lung of acute and established infection as well as in chronically infected mice. Furthermore, TNF inhibition significantly reduced lung pathology as compared to TB chemotherapy alone. Therefore, the experimental data suggest that TB chemotherapy may be more effective in the presence of a TNF inhibitor, which may be relevant to eradicate mycobacteria during chronic M. tuberculosis infection or reactivation.
    01/2013; 2(1):124-34.
  • Source
    Understanding Tuberculosis - Analyzing the Origin of Mycobacterium Tuberculosis Pathogenicity, 02/2012; , ISBN: 978-953-307-942-4
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tuberculosis (TB) lesions are extremely complex and dynamic. Here, we review the multiple types and fates of pulmonary lesions that form following infection by Mycobacterium tuberculosis and the impact of this spatial and temporal heterogeneity on the bacteria they harbor. The diverse immunopathology of granulomas and cavities generates a plethora of microenvironments to which M. tuberculosis bacilli must adapt. This in turn affects the replication, metabolism, and relative density of bacterial subpopulations, and consequently their respective susceptibility to chemotherapy. We outline recent developments that support a paradigm shift in our understanding of lesion progression. The simple model according to which lesions within a single individual react similarly to the systemic immune response no longer prevails. Host-pathogen interactions within lesions are a dynamic process, driven by subtle and local differences in signaling pathways, resulting in diverging trajectories of lesions within a single host. The spectrum of TB lesions is a continuum with a large overlap in the lesion types found in latently infected and active TB patients. We hope this overview will guide TB researchers in the design, choice of read-outs, and interpretation of future studies in the search for predictive biomarkers and novel therapies. © 2015 The Authors. Immunological Reviews Published by John Wiley & Sons Ltd.
    Immunological Reviews 03/2015; 264(1). DOI:10.1111/imr.12252 · 12.91 Impact Factor