Doxycycline host-directed therapy in human pulmonary tuberculosis.

Area of Science:

• Immunology
• Microbiology
• Pharmacology

Background:

• Matrix metalloproteinases (MMPs) are implicated in tissue destruction during tuberculosis (TB).
• MMPs represent potential targets for host-directed therapies in TB management.
• Doxycycline, a broad-spectrum MMP inhibitor, was investigated in a clinical trial for pulmonary TB.

Purpose of the Study:

• To evaluate the efficacy and safety of doxycycline as an adjunctive therapy in patients with pulmonary TB.
• To assess the impact of doxycycline on gene expression, MMP activity, and lung tissue integrity in TB patients.

Main Methods:

• A phase II, double-blind, randomized, controlled trial was conducted.
• Thirty pulmonary TB patients received either doxycycline (100 mg twice daily) or placebo for 14 days, alongside standard anti-TB treatment.
• Whole blood RNA-sequencing and sputum/plasma MMP levels were analyzed.

Main Results:

• Doxycycline accelerated the normalization of dysregulated gene expression, including down-regulation of interferon and innate immune response genes.
• Adjunctive doxycycline significantly reduced various MMPs in sputum and suppressed collagen/elastin destruction.
• The treatment led to a reduction in pulmonary cavity volume and was found to be safe, with effects persisting post-treatment.

Conclusions:

• Adjunctive doxycycline effectively suppressed pathological MMPs in pulmonary TB patients.
• Doxycycline demonstrated potential in mitigating TB-associated immunopathology.
• Larger clinical trials are recommended to further explore the benefits of adjunctive doxycycline in TB treatment.