NAD+-boosting compounds enhance nitric oxide production and prevent oxidative stress in endothelial cells exposed to plasma from patients with COVID-19

Preservation of Vascular Endothelial Function in Late-Onset Postmenopausal Women

BACKGROUND

Postmenopausal women (PMW) who complete menopause at a late age (55+ years) have lower cardiovascular disease risk than PMW who complete menopause at a normal age (45-54 years). However, the influence of late-onset menopause on vascular endothelial dysfunction is unknown. Moreover, the mechanisms by which a later age at menopause may modulate endothelial function remain to be determined.

METHODS

We measured endothelial function (brachial artery flow-mediated dilation [FMDBA]) in age-matched late- and normal-onset PMW and a young premenopausal reference group. We determined mitochondrial reactive oxygen species (mitoROS)-related suppression of endothelial function (change in FMDBA with an acute dose of the mitochondria-targeted antioxidant MitoQ; ΔFMDBA, MTQ) in PMW. The effects of serum from late- and normal-onset PMW and premenopausal women on mitoROS bioactivity in human aortic endothelial cells in culture were assessed. Metabolomics analyses in combination with serum metabolite level normalization and human aortic endothelial cell serum exposure experiments were performed to identify the circulating factors contributing to the serum effects on endothelial cell mitoROS bioactivity.

RESULTS

FMDBA in PMW was lower than in premenopausal women. However, FMDBA was >50% higher in late- versus normal-onset PMW and positively related to age at menopause. ΔFMDBA, MTQ was >50% lower in late- versus normal-onset PMW. Serum from normal-onset PMW but not late-onset PMW induced higher mitoROS bioactivity in human aortic endothelial cells compared with serum from premenopausal women. MitoROS bioactivity was negatively related to FMDBA and age at menopause. Seventeen metabolites significantly differed between late- and normal-onset PMW; 15 were lipid specific; 8 were triglyceride derived. TG(16:0) was most strongly correlated with mitoROS bioactivity. Normalization of TG(16:0) concentrations in serum from premenopausal women and late-onset PMW to match serum levels in normal-onset PMW abrogated differences in mitoROS bioactivity in serum-treated human aortic endothelial cells.

CONCLUSIONS

Late-onset menopause is associated with preservation of endothelial function, which is mediated by lower mitoROS-associated oxidative stress. A more favorable profile of circulating lipid metabolites, specifically triglyceride-derived metabolites, contributes to lower endothelial cell mitoROS in late-onset PMW. These findings provide new insight into the possible mechanisms of reduced cardiovascular disease risk in late-onset menopause.

Decoding NAD+ Metabolism in COVID-19: Implications for Immune Modulation and Therapy

The persistent threat of COVID-19, particularly with the emergence of new variants, underscores the urgency for innovative therapeutic strategies beyond conventional antiviral treatments. Current immunotherapies, including IL-6/IL-6R monoclonal antibodies and JAK inhibitors, exhibit suboptimal efficacy, necessitating alternative approaches. Our review delves into the significance of NAD+ metabolism in COVID-19 pathology, marked by decreased NAD+ levels and upregulated NAD+-consuming enzymes such as CD38 and poly (ADP-ribose) polymerases (PARPs). Recognizing NAD+'s pivotal role in energy metabolism and immune modulation, we propose modulating NAD+ homeostasis could bolster the host's defensive capabilities against the virus. The article reviews the scientific rationale behind targeting NAD+ pathways for therapeutic benefit, utilizing strategies such as NAD+ precursor supplementation and enzyme inhibition to modulate immune function. While preliminary data are encouraging, the challenge lies in optimizing these interventions for clinical use. Future research should aim to unravel the intricate roles of key metabolites and enzymes in NAD+ metabolism and to elucidate their specific mechanisms of action. This will be essential for developing targeted NAD+ therapies, potentially transforming the management of COVID-19 and setting a precedent for addressing other infectious diseases.

Mitochondria in COVID-19: from cellular and molecular perspective

The rapid development of the COVID-19 pandemic resulted in a closer analysis of cell functioning during β-coronavirus infection. This review will describe evidence for COVID-19 as a syndrome with a strong, albeit still underestimated, mitochondrial component. Due to the sensitivity of host mitochondria to coronavirus infection, SARS-CoV-2 affects mitochondrial signaling, modulates the immune response, modifies cellular energy metabolism, induces apoptosis and ageing, worsening COVID-19 symptoms which can sometimes be fatal. Various aberrations across human systems and tissues and their relationships with mitochondria were reported. In this review, particular attention is given to characterization of multiple alterations in gene expression pattern and mitochondrial metabolism in COVID-19; the complexity of interactions between SARS-CoV-2 and mitochondrial proteins is presented. The participation of mitogenome fragments in cell signaling and the occurrence of SARS-CoV-2 subgenomic RNA within membranous compartments, including mitochondria is widely discussed. As SARS-CoV-2 severely affects the quality system of mitochondria, the cellular background for aberrations in mitochondrial dynamics in COVID-19 is additionally characterized. Finally, perspectives on the mitigation of COVID-19 symptoms by affecting mitochondrial biogenesis by numerous compounds and therapeutic treatments are briefly outlined.

Electronic hookah (waterpipe) vaping reduces vascular endothelial function: the role of nicotine

Vaping has risen substantially in recent years, particularly among young adults. Electronic (e-) hookahs are a newer category of vaping devices touted as safer tobacco alternatives. Although e-hookah vaping acutely reduces endothelial function, the role of nicotine and the mechanisms by which it may impair endothelial function remain understudied. In a randomized crossover study, we investigated the acute effects of vaping e-hookah, with and without nicotine, as compared with sham on endothelial function assessed by brachial artery flow-mediated dilation (FMD), among 18 overtly healthy young adults. To determine the role of changes in circulating factors in plasma on endothelial cell function, human umbilical vein endothelial cells (HUVECs) were cultured with participants' plasma, and acetylcholine-stimulated nitric oxide (NO) production and basal reactive oxygen species (ROS) bioactivity were assessed. Plasma nicotine was measured before and after the sessions. E-hookah vaping with nicotine, which acutely increased heart rate (HR) by 8 ± 3 beats/min and mean arterial pressure (MAP) by 7 ± 2 mmHg (means ± SE; P < 0.05), decreased endothelial-dependent FMD by 1.57 ± 0.19%Δ (P = 0.001), indicating impairment in endothelial function. Vaping e-hookah without nicotine, which mildly increased hemodynamics (HR, 2 ± 2 beats/min and MAP 1 ± 1 mmHg; P = ns), did not significantly impair endothelial function. No changes were observed after sham vaping. HUVECs cultured with participants' plasma after versus before e-hookah vaping with nicotine, but not without nicotine or sham vaping, exhibited reductions in endothelial cell NO bioavailability and increases in ROS bioactivity (P < 0.05). Plasma nicotine concentrations increased after vaping e-hookah with nicotine (6.7 ± 1.8 ng/mL; P = 0.002), whereas no changes were observed after vaping e-hookah without nicotine or sham (P = ns). Acute e-hookah vaping induces endothelial dysfunction by impairing NO bioavailability associated with increased ROS production, and these effects are attributable to nicotine, not to nonnicotine constituents, present in the flavored e-liquid.NEW & NOTEWORTHY Despite safety claims heavily advertised by the hookah tobacco industry, acute e-hookah vaping induces in vivo endothelial dysfunction by impairing ex vivo NO bioavailability associated with increased ROS production. These effects are attributable to nicotine, not to nonnicotine constituents, present in the flavored e-liquid.