Host-Directed Therapy with Inhalable Lovastatin Microspheres for Matrix Metalloproteinase Inhibition in Tuberculosis

Tuberculosis (TB) triggers a robust immune response, which leads to significant destruction of the lung tissue at the site of infection, aiding in the transmission of Mycobacterium tuberculosis (Mtb) to the hosts. The excessive inflammatory response contributes heavily to extracellular matrix (ECM) damage, which is linked to high mortality rates among TB patients. Matrix metalloproteinases (MMPs), particularly MMP-2 and MMP-9, are pivotal in the breakdown of the ECM, worsening tissue destruction. In the context of host-directed therapy (HDT), a strategy aimed at modulating the immune response rather than directly targeting the pathogen, we evaluated the potential of lovastatin (LOV). LOV has shown promise in reducing MMP activity and inflammation, which could alleviate the immune-mediated pathology in TB. However, its clinical use has been limited due to poor solubility and biocompatibility, reducing its therapeutic efficacy. To overcome these limitations, we designed inhalable gelatin microspheres (GA-MS) loaded with LOV using the spray-drying technology. This approach improved the solubility and allowed for the controlled release of the drug. The resulting LOV-loaded gelatin microspheres (LOV/GA-MS) had an optimal particle size of 2.395 ± 0.67 μm, facilitating macrophage uptake due to their aerodynamic properties. In in vitro studies using Mtb-infected macrophages, LOV/GA-MS effectively suppressed MMP expression and reduced levels of pro-inflammatory cytokines at a concentration of 20 μg/mL, demonstrating substantial anti-inflammatory potential. Moreover, these microspheres showed a synergistic effect when combined with standard anti-TB drugs, enhancing the overall therapeutic efficacy in in vitro experiments. The findings suggest that inhalable LOV/GA-MS microspheres represent a promising adjunctive host-directed therapy for TB. By modulating the host's immune response and targeting key inflammatory mediators such as MMPs, this approach could mitigate lung tissue damage, improve clinical outcomes, and provide a more holistic treatment option for TB.