Background: Lung lesions may develop from tissue reactions to known or unknown stimuli and present with different morphological descriptions. The pathogenesis may be induced and maintained by different bioactive substances, of which, the upregulation matrix metalloproteinases (MMPs) play a vital role. Inhibition of the MMPs, therefore, may be a prospective mode of therapy for such lesions.
Materials and methods: A number of patients with lung lesions of different morphologies and presentations were treated empirically with long-term oral doxycycline (100 mg BID) upon exclusion of malignancy and infection in an open, single-arm, prospective, observational pilot study. The effect of the treatment was recorded on serial x-rays/computed tomography (CT) scans and the impact of treatment was measured with a visual analog scale (VAS) or a Likert-like scale. Furthermore, six independent pulmonologists' opinion (expressed on a '0' to '100' scale) were pooled with regard to the significance and the expectedness of such a change.
Results: Twenty-six patients (mean age 49.33 years and male: female ratio = 10:3) with different types of pulmonary parenchymal/pleural lesions were treated with long-term oral doxycycline for a mean duration of 386.88 days related to the available radiological comparison. They showed a mean improvement of 3.99 on the Likert-like scale and 78% on the VAS scale. The mean significance of the change was 83.33%, with a mean expectedness of 18% as per the pooled opinion of the pulmonologists.
Inference: The significant and unexpected resolution of different tissue lesions from long-term doxycycline appears to be a novel observation. This needs proper scientific validation.
Keywords: Doxycycline; lung lesions; matrix metalloproteinase.