Hyperglycemia modulates M1/M2 macrophage polarization in chronic diabetic patients with pulmonary tuberculosis infection
Sudhasini Panda, Alisha Arora, Kalpana Luthra, Anant Mohan, Naval K. Vikram, Neeraj Kumar Gupta, Archana Singh
Abstract
Increased susceptibility to bacterial infections like tuberculosis (TB) is one of the complications of type 2 diabetes, however the underlying mechanisms remains poorly characterized. To explore how chronic hyperglycemia in diabetes affects progression of active TB, we examined mRNA expression of M1 (proinflammatory) and M2 (anti-inflammatory) cytokines/markers, in monocyte-derived macrophages obtained from patients with PTB + DM (pulmonary TB + diabetes mellitus type 2), patients with DM alone, patients with PTB alone, and healthy individuals (controls). Our findings indicate a dysregulated cytokine response in patients with both PTB and DM, characterized by decreased expression levels of interferon-gamma (IFN-γ) and inducible nitric oxide synthase (iNOS), along with increased expression levels of interleukin-1 beta (IL-1β) and CD206. Furthermore, we observed a positive correlation of IL-1β and CD206 expression with levels of glycosylated hemoglobin (HbA1c) in both PTB + DM and DM groups, while IFN-γ showed a positive correlation with HbA1c levels, specifically in the PTB + DM group. Additionally, M1 cytokines/markers, IL-1β and iNOS were found to be significantly associated with the extent of sputum positivity in both PTB and PTB + DM groups, suggesting it to be a function of increased bacterial load and hence severity of infection. Our data demonstrates that tuberculosis in individuals with PTB + DM is characterized by altered M1/M2 cytokine responses, indicating that chronic inflammation associated with type 2 diabetes may contribute to increased immune pathology and inadequate control of tuberculosis infection.