Lipoic acid modulates inflammatory responses of monocytes and monocyte-derived macrophages from healthy and relapsing-remitting multiple sclerosis subjects
Immunol Cell Biol. 2020 Aug 6. doi: 10.1111/imcb.12392.
Multiple Sclerosis (MS) is a disabling neuro-inflammatory disease. Its etiology is unknown, but both oxidative stress and inflammation appear to be involved in disease pathology. Macrophages are the predominant cell type in acute inflammatory brain lesions in MS. Macrophages produce pro-inflammatory and toxic molecules that promote demyelination and are key players in phagocytosis/degradation of myelin sheathes. Lipoic acid (LA) is an inexpensive, endogenously-produced small molecule that exhibits antioxidant and anti-inflammatory effects. Treatment with LA is protective in MS and other inflammatory diseases. To examine the mechanism(s) by which LA may attenuate inflammatory lesion activity in MS, we used healthy control and MS cells to evaluate the effects of LA on levels of inflammatory cytokines, phagocytosis, and the immunomodulator cyclic AMP (cAMP) in monocytes and monocyte-derived macrophages (MDM). LA treatment resulted in a generally less inflammatory phenotype of monocytes and MDM from HC, and (to a lesser degree) MS donors. LA inhibited monocyte secretion of cytokines relevant to MS in monocytes, including TNF-α, IL-6 and IL-1β; LA effects on secretion of these cytokines in MDM was mixed with inhibition of TNF-α and IL-6, but stimulation of IL-1β, the latter perhaps due to altered macrophage polarization. LA inhibited phagocytosis in both monocytes and MDM, and increased cAMP levels in monocytes. LA may modulate inflammatory cytokine secretion and phagocytosis via a cAMP-mediated mechanism.
Lipoic acid modulates inflammatory response in RRMS
Re: Lipoic acid modulates inflammatory response in RRMS
Lipoic Acid Stimulates cAMP Production in Healthy Control and Secondary Progressive MS Subjects
Mol Neurobiol. 2018 Jul;55(7):6037-6049.
Lipoic acid (LA) exhibits antioxidant and anti-inflammatory properties; supplementation reduces disease severity and T lymphocyte migration into the central nervous system in a murine model of multiple sclerosis (MS), and administration in secondary progressive MS (SPMS) subjects reduces brain atrophy compared to placebo. The mechanism of action (MOA) of LA's efficacy in suppression of MS pathology is incompletely understood. LA stimulates production of the immunomodulator cyclic AMP (cAMP) in vitro. To determine whether cAMP could be involved in the MOA of LA in vivo, we performed a clinical trial to examine whether LA stimulates cAMP production in healthy control and MS subjects, and whether there are differences in the bioavailability of LA between groups. We administered 1200 mg of oral LA to healthy control, relapsing remitting MS (RRMS) and SPMS subjects, and measured plasma LA and cAMP levels in peripheral blood mononuclear cells (PBMCs). There were no significant differences between the groups in pharmacokinetic (PK) parameters. Healthy and SPMS subjects had increased cAMP at 2 and 4 h post-LA treatment compared to baseline, while RRMS subjects showed decreases in cAMP. Additionally, plasma concentrations of prostaglandin E2 (PGE2, a known cAMP stimulator) were significantly lower in female RRMS subjects compared to female HC and SPMS subjects 4 h after LA ingestion. These data indicate that cAMP could be part of the MOA of LA in SPMS, and that there is a divergent response to LA in RRMS subjects that may have implications in the efficacy of immunomodulatory drugs. This clinical trial, "Defining the Anti-inflammatory Role of Lipoic Acid in Multiple Sclerosis," NCT00997438, is registered at https://clinicaltrials.gov/ct2/show/record/NCT00997438 .
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Mol Neurobiol. 2018 Jul;55(7):6037-6049.
Lipoic acid (LA) exhibits antioxidant and anti-inflammatory properties; supplementation reduces disease severity and T lymphocyte migration into the central nervous system in a murine model of multiple sclerosis (MS), and administration in secondary progressive MS (SPMS) subjects reduces brain atrophy compared to placebo. The mechanism of action (MOA) of LA's efficacy in suppression of MS pathology is incompletely understood. LA stimulates production of the immunomodulator cyclic AMP (cAMP) in vitro. To determine whether cAMP could be involved in the MOA of LA in vivo, we performed a clinical trial to examine whether LA stimulates cAMP production in healthy control and MS subjects, and whether there are differences in the bioavailability of LA between groups. We administered 1200 mg of oral LA to healthy control, relapsing remitting MS (RRMS) and SPMS subjects, and measured plasma LA and cAMP levels in peripheral blood mononuclear cells (PBMCs). There were no significant differences between the groups in pharmacokinetic (PK) parameters. Healthy and SPMS subjects had increased cAMP at 2 and 4 h post-LA treatment compared to baseline, while RRMS subjects showed decreases in cAMP. Additionally, plasma concentrations of prostaglandin E2 (PGE2, a known cAMP stimulator) were significantly lower in female RRMS subjects compared to female HC and SPMS subjects 4 h after LA ingestion. These data indicate that cAMP could be part of the MOA of LA in SPMS, and that there is a divergent response to LA in RRMS subjects that may have implications in the efficacy of immunomodulatory drugs. This clinical trial, "Defining the Anti-inflammatory Role of Lipoic Acid in Multiple Sclerosis," NCT00997438, is registered at https://clinicaltrials.gov/ct2/show/record/NCT00997438 .
Free full text.