Effects of Intense Exercise on Innate Bacterial Killing in Close Contacts of Patients with Tb/Mdr-Tb

Abstract

BackgroundClose contacts of patients with multidrug-resistant tuberculosis (MDR-TB) face a high infection risk due to limited chemoprophylaxis. Exercise is known to enhance the lung defense mechanisms. This study evaluated whether intense exercise can boost innate bacterial immunity in close contact by improving the in vitro killing of intracellular Mycobacterium tuberculosis.MethodsTwelve males (20–40 years) from a tuberculosis clinic were randomly assigned to exercise or no-exercise groups. The exercise group performed high-intensity cycling at 70–80% of heart rate reserve (HRR) for 30–60 min, three days/week for 12 weeks. The no-exercise group engaged in the self-directed exercise. Blood monocytes were isolated before and after the program and differentiated into inflammatory M1 and anti-inflammatory M2 macrophages. We infected the isolated monocytes and M1 and M2 macrophages with the mCherry-expressing laboratory reference M. tuberculosis strain H37Rv and a local strain of MDR-TB with a multiplicity of infection (MOI) is 10 for 0 and 72 h, and mycobacterial survival was determined via high content imaging.ResultsMycobacterial survival percentages were normalized to the 0-h infection control. In the exercise group, H37Rv survival was significantly decreased in monocytes, M1, and M2 macrophages compared to that in the no-exercise group. However, the local MDR strain reduced the survival of M1 macrophages but not that of monocytes or M2 macrophages.ConclusionIntense exercise may enhance mycobacterial killing in individuals exposed to TB, particularly inflammatory M1 macrophages, suggesting a potential role in improving immune defense against TB/MDR-TB. Promoting intense exercise among close contacts of patients with TB may be beneficial.

Note:
Funding declaration: This study was supported by the Fogarty International Center and the National Institute of Allergy and Infectious Diseases, of the National Institutes of Health under Award Number D43 TW009522. This study was funded by the Medical Research fund of the Faculty of Medicine, Prince of Songkla University, under Funded Number 64-057-3.

Conflict of Interests: All authors declare that they have no Conflict of Interest.

Ethical Approval: The study protocol was reviewed and approved by the Human Research Ethics Committee, Faculty of Medicine, Prince of Songkla University (REC.63-054-181), and by Makarak Hospital (No. 6/64).

Trial Registration: TCTR 20211111007

Keywords: intense exercise, macrophage function, bacterial killing, closed contact, Mycobacterium tuberculosis