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Severe and chronic infections, including pneumonia, sepsis, and tuberculosis (TB), induce long-lasting epigenetic changes that are associated with an increase in all-cause postinfectious morbidity and mortality. Oncology studies identified metabolic drivers of the epigenetic landscape, with the tricarboxylic acid (TCA) cycle acting as a central hub. It is unknown if the TCA cycle also regulates epigenetics, specifically DNA methylation, after infection-induced immune tolerance. The following studies demonstrate that lipopolysaccharide and Mycobacterium tuberculosis induce changes in DNA methylation that are mediated by the TCA cycle. Infection-induced DNA hypermethylation is mitigated by inhibitors of cellular metabolism (rapamycin, everolimus, metformin) and the TCA cycle (isocitrate dehydrogenase inhibitors). Conversely, exogenous supplementation with TCA metabolites (succinate and itaconate) induces DNA hypermethylation and immune tolerance. Finally, TB patients who received everolimus have less DNA hypermethylation demonstrating proof of concept that metabolic manipulation can mitigate epigenetic scars. [ABSTRACT FROM AUTHOR]

Cognitive decline frequently occurs with increasing age, but mechanisms contributing to age-associated cognitive decline (ACD) are not well understood and solutions are lacking. Understanding and reversing mechanisms contributing to ACD are important because increased age is identified as the single most important risk factor for dementia. We reported earlier that ACD in older humans is associated with glutathione (GSH) deficiency, oxidative stress (OxS), mitochondrial dysfunction, glucose dysmetabolism and inflammation, and that supplementing GlyNAC (glycine and N-acetylcysteine) improved these defects. To test whether these defects occur in the brain in association with ACD, and could be improved/reversed with GlyNAC supplementation, we studied young (20-week) and old (90-week) C57BL/6J mice. Old mice received either regular or GlyNAC supplemented diets for 8 weeks, while young mice received the regular diet. Cognition and brain outcomes (GSH, OxS, mitochondrial energetics, autophagy/mitophagy, glucose transporters, inflammation, genomic damage and neurotrophic factors) were measured. Compared to young mice, the old-control mice had significant cognitive impairment and multiple brain defects. GlyNAC supplementation improved/corrected the brain defects and reversed ACD. This study finds that naturally-occurring ACD is associated with multiple abnormalities in the brain, and provides proof-of-concept that GlyNAC supplementation corrects these defects and improves cognitive function in aging.

Abstract Background Oxidative stress (OxS) and mitochondrial dysfunction are implicated as causative factors for aging. Older adults (OAs) have an increased prevalence of elevated OxS, impaired mitochondrial fuel‐oxidation (MFO), elevated inflammation, endothelial dysfunction, insulin resistance, cognitive decline, muscle weakness, and sarcopenia, but contributing mechanisms are unknown, and interventions are limited/lacking. We previously reported that inducing deficiency of the antioxidant tripeptide glutathione (GSH) in young mice results in mitochondrial dysfunction, and that supplementing GlyNAC (combination of glycine and N‐acetylcysteine [NAC]) in aged mice improves naturally‐occurring GSH deficiency, mitochondrial impairment, OxS, and insulin resistance. This pilot trial in OA was conducted to test the effect of GlyNAC supplementation and withdrawal on intracellular GSH concentrations, OxS, MFO, inflammation, endothelial function, genotoxicity, muscle and glucose metabolism, body composition, strength, and cognition. Methods A 36‐week open‐label clinical trial was conducted in eight OAs and eight young adults (YAs). After all the participants underwent an initial (pre‐supplementation) study, the YAs were released from the study. OAs were studied again after GlyNAC supplementation for 24 weeks, and GlyNAC withdrawal for 12 weeks. Measurements included red‐blood cell (RBC) GSH, MFO; plasma biomarkers of OxS, inflammation, endothelial function, glucose, and insulin; gait‐speed, grip‐strength, 6‐min walk test; cognitive tests; genomic‐damage; glucose‐production and muscle‐protein breakdown rates; and body‐composition. Results GlyNAC supplementation for 24 weeks in OA corrected RBC‐GSH deficiency, OxS, and mitochondrial dysfunction; and improved inflammation, endothelial dysfunction, insulin‐resistance, genomic‐damage, cognition, strength, gait‐speed, and exercise capacity; and lowered body‐fat and waist‐circumference. However, benefits declined after stopping GlyNAC supplementation for 12 weeks. Conclusions GlyNAC supplementation for 24‐weeks in OA was well tolerated and lowered OxS, corrected intracellular GSH deficiency and mitochondrial dysfunction, decreased inflammation, insulin‐resistance and endothelial dysfunction, and genomic‐damage, and improved strength, gait‐speed, cognition, and body composition. Supplementing GlyNAC in aging humans could be a simple and viable method to promote health and warrants additional investigation.

Patients with type 2 diabetes (T2D) are known to have mitochondrial dysfunction and increased insulin resistance (IR), but the underlying mechanisms are not well understood. We reported previously that (a) adequacy of the antioxidant glutathione (GSH) is necessary for optimal mitochondrial fatty-acid oxidation (MFO); (b) supplementing the GSH precursors glycine and N-acetylcysteine (GlyNAC) in mice corrected GSH deficiency, reversed impaired MFO, and lowered oxidative stress (OxS) and IR; and (c) supplementing GlyNAC in patients with T2D improved GSH synthesis and concentrations, and lowered OxS. However, the effect of GlyNAC on MFO, MGO (mitochondrial glucose oxidation), IR and plasma FFA (free-fatty acid) concentrations in humans with T2D remains unknown. This manuscript reports the effect of supplementing GlyNAC for 14-days on MFO, MGO, IR and FFA in 10 adults with T2D and 10 unsupplemented non-diabetic controls. Fasted T2D participants had 36% lower MFO (p < 0.001), 106% higher MGO (p < 0.01), 425% higher IR (p < 0.001) and 76% higher plasma FFA (p < 0.05). GlyNAC supplementation significantly improved fasted MFO by 30% (p < 0.001), lowered MGO by 47% (p < 0.01), decreased IR by 22% (p < 0.01) and lowered FFA by 25% (p < 0.01). These results provide proof-of-concept that GlyNAC supplementation could improve mitochondrial dysfunction and IR in patients with T2D, and warrant additional research.

Humanity is battling a respiratory pandemic pneumonia named COVID-19 which has resulted in millions of hospitalizations and deaths. COVID-19 exacerbations occur in waves that continually challenge healthcare systems globally. Therefore, there is an urgent need to understand all mechanisms by which COVID-19 results in health deterioration to facilitate the development of protective strategies. Oxidative stress (OxS) is a harmful condition caused by excess reactive-oxygen species (ROS) and is normally neutralized by antioxidants among which Glutathione (GSH) is the most abundant. GSH deficiency results in amplified OxS due to compromised antioxidant defenses. Because little is known about GSH or OxS in COVID-19 infection, we measured GSH, TBARS (a marker of OxS) and F2-isoprostane (marker of oxidant damage) concentrations in 60 adult patients hospitalized with COVID-19. Compared to uninfected controls, COVID-19 patients of all age groups had severe GSH deficiency, increased OxS and elevated oxidant damage which worsened with advancing age. These defects were also present in younger age groups, where they do not normally occur. Because GlyNAC (combination of glycine and N-acetylcysteine) supplementation has been shown in clinical trials to rapidly improve GSH deficiency, OxS and oxidant damage, GlyNAC supplementation has implications for combating these defects in COVID-19 infected patients and warrants urgent investigation.

Background: Patients with HIV (PWH) develop geriatric comorbidities, including functional and cognitive decline at a younger age. However, contributing mechanisms are unclear and interventions are lacking. We hypothesized that deficiency of the antioxidant protein glutathione (GSH) contributes to multiple defects representing premature aging in PWH, and that these defects could be improved by supplementing the GSH precursors glycine and N-acetylcysteine (GlyNAC). Methods: We conducted an open label clinical trial where eight PWH and eight matched uninfected-controls were studied at baseline. PWH were studied again 12-weeks after receiving GlyNAC, and 8-weeks after stopping GlyNAC. Controls did not receive supplementation. Outcome measures included red-blood cell and muscle GSH concentrations, mitochondrial function, mitophagy and autophagy, oxidative stress, inflammation, endothelial function, genomic damage, insulin resistance, glucose production, muscle-protein breakdown rates, body composition, physical function and cognition. Results: PWH had significant defects in measured outcomes, which improved with GlyNAC supplementation. However, benefits receded after stopping GlyNAC. Conclusions: This open label trial finds that PWH have premature aging based on multiple biological and functional defects, and identifies novel mechanistic explanations for cognitive and physical decline. Nutritional supplementation with GlyNAC improves comorbidities suggestive of premature aging in PWH including functional and cognitive decline, and warrants additional investigation.