The Effects of Oral Liposomal Glutathione and In Vitro Everolimus in Altering the Immune Responses against Mycobacterium bovis BCG Strain in Individuals with Type 2 Diabetes

Abstract

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tb) still remains a devastating infectious disease in the world. There has been a daunting increase in the incidence of Type 2 Diabetes Mellitus (T2DM) worldwide. T2DM patients are three times more vulnerable to M. tb infection compared to healthy individuals. TB-T2DM coincidence is a challenge for global health control. Despite some progress in the research, M. tb still has unexplored characteristics in successfully evading host defenses. The lengthy duration of treatment, the emergence of multi-drug-resistant strains and extensive-drug-resistant strains of M. tb have made TB treatment very challenging. Previously, we have tested the antimycobacterial effects of everolimus within in vitro granulomas generated from immune cells derived from peripheral blood of healthy subjects. However, the effectiveness of everolimus treatment against mycobacterial infection in individuals with T2DM is unknown. Furthermore, the effectiveness of the combination of in vivo glutathione (GSH) supplementation in individuals with T2DM along with in vitro treatment of isolated immune cells with everolimus against mycobacterial infection has never been tested. Therefore, we postulated that liposomal glutathione (L-GSH) and everolimus would offer great hope for developing adjunctive therapy for mycobacterial infection. L-GSH or placebo was administered to T2DM individuals orally for three months. Study subjects’ blood was drawn pre- and post-L-GSH/or placebo supplementation, where Peripheral Blood Mononuclear Cells (PBMCs) were isolated from whole blood to conduct in vitro studies with everolimus. We found that in vitro treatment with everolimus, an mTOR (membrane target of rapamycin) inhibitor, significantly reduced intracellular M. bovis BCG infection alone and in conjunction with L-GSH supplementation. Furthermore, we found L-GSH supplementation coupled with in vitro everolimus treatment produced a greater effect in inhibiting the growth of intracellular Mycobacterium bovis BCG, than with the everolimus treatment alone. We also demonstrated the functions of L-GSH along with in vitro everolimus treatment in modulating the levels of cytokines such as IFN-γ, TNF-α, and IL-2 and IL-6, in favor of improving control of the mycobacterial infection. In summary, in vitro everolimus-treatment alone and in combination with oral L-GSH supplementation for three months in individuals with T2DM, was able to increase the levels of T-helper type 1 (Th1) cytokines IFN-γ, TNF-α, and IL-2 as well as enhance the abilities of granulomas from individuals with T2DM to improve control of a mycobacterial infection.

Effects of Glutathione Diminishment on the Immune Responses against Mycobacterium tuberculosis Infection

“…In addition, in vitro M. tb survival and growth in infected PBMCs from T2DM patients is significantly increased compared to healthy controls [17]. Similar to previous studies performed with HIV-positive patients, supplementation with a liposomal formulation of GSH in T2DM subjects restored GSH levels and consequently decreased oxidative stress, modulated a Th-1 cytokine response to M. tb, and enhanced in vitro granuloma formation and M. tb control [8,[17][18][19]. Altogether, these studies suggest that GSH fills important immunomodulatory roles in granuloma formation and in the control of M. tb growth in vitro.…”

GPX4 regulates cellular necrosis and host resistance in Mycobacterium tuberculosis infection

“…The results presented here support an important role for the Gpx4-dependent glutathione metabolic pathway in the regulation of Mtb-induced necrosis and implicate this process as a potential target for host-directed therapy of tuberculosis. In this regard, glutathione itself has been shown to regulate Mtb infection outcomes in several murine experimental and clinical TB studies ( Cao et al, 2021 ; Guerra et al, 2011 ; Morris et al, 2013 ; Safe et al, 2020a ; Safe et al, 2020b ; To et al, 2021 ; Venketaraman et al, 2008 ; Venketaraman et al, 2006 ), but to the best of our knowledge glutathione administration, in its reduced form, has never been tested in a formal clinical trial in TB patients. In terms of Gpx4 itself, any HDT specifically targeting this enzyme would have to increase rather than inhibit its activity to be an effective therapy.…”

Immune-Enhancing Treatment among Acute Necrotizing Pancreatitis Patients with Metabolic Abnormalities: A Post Hoc Analysis of a Randomized Clinical Trial

“…Attempts have been made in boosting the immune system in patients with diabetes, including liposomal glutathione, 33 mechanistic target of rapamycin inhibitor, 34 and microbiological and immunological enteral nutrition. 35 But none of them targeted the innate immune system directly.…”