Combined Metabolic Activators Accelerates Recovery in Mild-to-Moderate COVID-19

Recent advances in nutritional metabolism studies on SARS-CoV-2 infection

In the context of the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), metabolic research has become crucial for in-depth exploration of viral infection mechanisms and in searching for therapeutic strategies. This paper summarizes the interrelationships between carbohydrate, lipid, and amino acid metabolism and COVID-19 infection, discussing their roles in infection progression. SARS-CoV-2 infection leads to insulin resistance and increased glycolysis, reducing glucose utilization and shifting metabolism to use fat as an energy source. Fat is crucial for viral replication, and imbalances in amino acid metabolism may interfere with immune regulation. Consequently, metabolic changes such as hyperglycemia, hypolipidemia, and deficiency of certain amino acids following SARS-CoV-2 infection can contribute to progression toward severe conditions. These metabolic pathways not only have potential value in prediction and diagnosis but also provide new perspectives for the development of therapeutic strategies. By monitoring metabolic changes, infection severity can be predicted early, and modulating these metabolic pathways may help reduce inflammatory responses, improve immune responses, and reduce the risk of thrombosis. Research on the relationship between metabolism and SARS-CoV-2 infection provides an important scientific basis for addressing the global challenge posed by COVID-19, however, further studies are needed to validate these findings and provide more effective strategies for disease control.

Genome-scale models in human metabologenomics

Metabologenomics integrates metabolomics with other omics data types to comprehensively study the genetic and environmental factors that influence metabolism. These multi-omics data can be incorporated into genome-scale metabolic models (GEMs), which are highly curated knowledge bases that explicitly account for genes, transcripts, proteins and metabolites. By including all known biochemical reactions catalysed by enzymes and transporters encoded in the human genome, GEMs analyse and predict the behaviour of complex metabolic networks. Continued advancements to the scale and scope of GEMs - from cells and tissues to microbiomes and the whole body - have helped to design effective treatments and develop better diagnostic tools for metabolic diseases. Furthermore, increasing amounts of multi-omics data are incorporated into GEMs to better identify the underlying mechanisms, biomarkers and potential drug targets of metabolic diseases.

Multi-omics characterization of improved cognitive functions in Parkinson's disease patients after the combined metabolic activator treatment: a randomized, double-blinded, placebo-controlled phase II trial

Parkinson's disease is primarily marked by mitochondrial dysfunction and metabolic abnormalities. We recently reported that the combined metabolic activators improved the immunohistochemical parameters and behavioural functions in Parkinson's disease and Alzheimer's disease animal models and the cognitive functions in Alzheimer's disease patients. These metabolic activators serve as the precursors of nicotinamide adenine dinucleotide and glutathione, and they can be used to activate mitochondrial metabolism and eventually treat mitochondrial dysfunction. Here, we designed a randomized, double-blinded, placebo-controlled phase II study in Parkinson's disease patients with 84 days combined metabolic activator administration. A single dose of combined metabolic activator contains L-serine (12.35 g), N-acetyl-L-cysteine (2.55 g), nicotinamide riboside (1 g) and L-carnitine tartrate (3.73 g). Patients were administered either one dose of combined metabolic activator or a placebo daily for the initial 28 days, followed by twice-daily dosing for the next 56 days. The main goal of the study was to evaluate the clinical impact on motor functions using the Unified Parkinson's Disease Rating Scale and to determine the safety and tolerability of combined metabolic activator. A secondary objective was to assess cognitive functions utilizing the Montreal Cognitive Assessment and to analyse brain activity through functional MRI. We also performed comprehensive plasma metabolomics and proteomics analysis for detailed characterization of Parkinson's disease patients who participated in the study. Although no improvement in motor functions was observed, cognitive function was shown to be significantly improved (P < 0.0000) in Parkinson's disease patients treated with the combined metabolic activator group over 84 days, whereas no such improvement was noted in the placebo group (P > 0.05). Moreover, a significant reduction (P = 0.001) in Montreal Cognitive Assessment scores was observed in the combined metabolic activator group, with no decline (P > 0.05) in the placebo group among severe Parkinson's disease patients with lower baseline Montreal Cognitive Assessment scores. We showed that improvement in cognition was associated with critical brain network alterations based on functional MRI analysis, especially relevant to areas with cognitive functions in the brain. Finally, through a comprehensive multi-omics analysis, we elucidated the molecular mechanisms underlying cognitive improvements observed in Parkinson's disease patients. Our results show that combined metabolic activator administration leads to enhanced cognitive function and improved metabolic health in Parkinson's disease patients as recently shown in Alzheimer's disease patients. The trial was registered in ClinicalTrials.gov NCT04044131 (17 July 2019, https://clinicaltrials.gov/ct2/show/NCT04044131).

Acute exercise boosts NAD+ metabolism of human peripheral blood mononuclear cells

Nicotinamide adenine dinucleotide (NAD+) coenzymes are the central electron carriers in biological energy metabolism. Low NAD+ levels are proposed as a hallmark of ageing and several diseases, which has given rise to therapeutic strategies that aim to tackle these conditions by boosting NAD+ levels. As a lifestyle factor with preventive and therapeutic effects, exercise increases NAD+ levels across various tissues, but so far human trials are mostly focused on skeletal muscle. Given that immune cells are mobilized and redistributed in response to acute exercise, we conducted two complementary trials to test the hypothesis that a single exercise session alters NAD+ metabolism of peripheral blood mononuclear cells (PBMCs). In a randomized crossover trial (DRKS00017686) with 24 young adults (12 female) we show that acute exercise increases gene expression and protein abundance of several key NAD+ metabolism enzymes with high conformity between high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT). In a longitudinal exercise trial (DRKS00029105) with 12 young adults (6 female) we confirm these results and reveal that - similar to skeletal muscle - NAD+ salvage is pivotal for PBMCs in response to exercise. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of NAD+ salvage pathway, displayed a pronounced increase in gene expression during exercise, which was accompanied by elevated intracellular NAD+ levels and reduced serum levels of the NAD+ precursor nicotinamide. These results demonstrate that acute exercise triggers NAD+ biosynthesis of human PBMCs with potential implications for immunometabolism, immune effector function, and immunological exercise adaptions.

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.

Dysregulated nicotinamide adenine dinucleotide metabolome in patients hospitalized with COVID-19

Nicotinamide adenine dinucleotide (NAD+) depletion has been postulated as a contributor to the severity of COVID-19; however, no study has prospectively characterized NAD+ and its metabolites in relation to disease severity in patients with COVID-19. We measured NAD+ and its metabolites in 56 hospitalized patients with COVID-19 and in two control groups without COVID-19: (1) 31 age- and sex-matched adults with comorbidities, and (2) 30 adults without comorbidities. Blood NAD+ concentrations in COVID-19 group were only slightly lower than in the control groups (p < 0.05); however, plasma 1-methylnicotinamide concentrations were significantly higher in patients with COVID-19 (439.7 ng/mL, 95% CI: 234.0, 645.4 ng/mL) than in age- and sex-matched controls (44.5 ng/mL, 95% CI: 15.6, 73.4) and in healthy controls (18.1 ng/mL, 95% CI 15.4, 20.8; p < 0.001 for each comparison). Plasma nicotinamide concentrations were also higher in COVID-19 group and in controls with comorbidities than in healthy control group. Plasma concentrations of 2-methyl-2-pyridone-5-carboxamide (2-PY), but not NAD+, were significantly associated with increased risk of death (HR = 3.65; 95% CI 1.09, 12.2; p = 0.036) and escalation in level of care (HR = 2.90, 95% CI 1.01, 8.38, p = 0.049). RNAseq and RTqPCR analyses of PBMC mRNA found upregulation of multiple genes involved in NAD+ synthesis as well as degradation, and dysregulation of NAD+-dependent processes including immune response, DNA repair, metabolism, apoptosis/autophagy, redox reactions, and mitochondrial function. Blood NAD+ concentrations are modestly reduced in COVID-19; however, NAD+ turnover is substantially increased with upregulation of genes involved in both NAD+ biosynthesis and degradation, supporting the rationale for NAD+ augmentation to attenuate disease severity.

Identifying Hub Genes and Metabolic Pathways in Collagen VI-Related Dystrophies: A Roadmap to Therapeutic Intervention

Collagen VI-related dystrophies (COL6RD) are a group of rare muscle disorders caused by mutations in specific genes responsible for type VI collagen production. It affects muscles, joints, and connective tissues, leading to weakness, joint problems, and structural issues. Currently, there is no effective treatment for COL6RD; its management typically addresses symptoms and complications. Therefore, it is essential to decipher the disease's molecular mechanisms, identify drug targets, and develop effective treatment strategies to treat COL6RD. In this study, we employed differential gene expression analysis, weighted gene co-expression network analysis, and genome-scale metabolic modeling to investigate gene expression patterns in COL6RD patients, uncovering key genes, significant metabolites, and disease-related pathophysiological pathways. First, we performed differential gene expression and weighted gene co-expression network analyses, which led to the identification of 12 genes (CHCHD10, MRPS24, TRIP10, RNF123, MRPS15, NDUFB4, COX10, FUNDC2, MDH2, RPL3L, NDUFB11, PARVB) as potential hub genes involved in the disease. Second, we utilized a drug repurposing strategy to identify pharmaceutical candidates that could potentially modulate these genes and be effective in the treatment. Next, we utilized context-specific genome-scale metabolic models to compare metabolic variations between healthy individuals and COL6RD patients. Finally, we conducted reporter metabolite analysis to identify reporter metabolites (e.g., phosphatidates, nicotinate ribonucleotide, ubiquinol, ferricytochrome C). In summary, our analysis revealed critical genes and pathways associated with COL6RD and identified potential targets, reporter metabolites, and candidate drugs for therapeutic interventions.

Potential association between COVID-19 and neurological disorders: analysis of common genes and therapeutics

As the COVID-19 pandemic persists, the increasing evidences suggest that the patients with COVID-19 may face the risks of the neurological complications and sequelae. To address this issue, we conducted a comprehensive study aimed at exploring the relationship between COVID-19 and various neurological disorders, with a particular focus on the shared dysregulated genes and the potential therapeutic targets. We selected six neurological disorders for investigation, including Alzheimer's disease, epilepsy, stroke, Parkinson's disease, and the sleep disorders. Through the bioinformatics analysis of the association between these disorders and COVID-19, we aimed to uncover the common molecular mechanisms and the potential treatment pathways. In this study, we utilized the publicly available RNA-Seq and microarray datasets, and employed tools such as Limma and DESeq2 for the differential gene analysis. Through the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, we explored the common biological features and pathways. Additionally, we focused on analyzing the regulatory roles of miRNA and transcription factors on the shared differentially expressed genes, and predicted the potential drugs interacting with these genes. These analyses contribute to a better understanding of the relationship between COVID-19 and the neurological disorders, and provide a theoretical basis for the future treatment strategies. Through this research, we aim to offer the deeper insights to the scientific community and present the new perspectives for the clinical practice in addressing the challenges of the neurological complications and sequelae faced by the COVID-19 patients.

Combined Metabolic Activators with Different NAD+ Precursors Improve Metabolic Functions in the Animal Models of Neurodegenerative Diseases

BACKGROUND

Mitochondrial dysfunction and metabolic abnormalities are acknowledged as significant factors in the onset of neurodegenerative disorders such as Parkinson's disease (PD) and Alzheimer's disease (AD). Our research has demonstrated that the use of combined metabolic activators (CMA) may alleviate metabolic dysfunctions and stimulate mitochondrial metabolism. Therefore, the use of CMA could potentially be an effective therapeutic strategy to slow down or halt the progression of PD and AD. CMAs include substances such as the glutathione precursors (L-serine and N-acetyl cysteine), the NAD+ precursor (nicotinamide riboside), and L-carnitine tartrate.

METHODS

Here, we tested the effect of two different formulations, including CMA1 (nicotinamide riboside, L-serine, N-acetyl cysteine, L-carnitine tartrate), and CMA2 (nicotinamide, L-serine, N-acetyl cysteine, L-carnitine tartrate), as well as their individual components, on the animal models of AD and PD. We assessed the brain and liver tissues for pathological changes and immunohistochemical markers. Additionally, in the case of PD, we performed behavioral tests and measured responses to apomorphine-induced rotations.

FINDINGS

Histological analysis showed that the administration of both CMA1 and CMA2 formulations led to improvements in hyperemia, degeneration, and necrosis in neurons for both AD and PD models. Moreover, the administration of CMA2 showed a superior effect compared to CMA1. This was further corroborated by immunohistochemical data, which indicated a reduction in immunoreactivity in the neurons. Additionally, notable metabolic enhancements in liver tissues were observed using both formulations. In PD rat models, the administration of both formulations positively influenced the behavioral functions of the animals.

INTERPRETATION

Our findings suggest that the administration of both CMA1 and CMA2 markedly enhanced metabolic and behavioral outcomes, aligning with neuro-histological observations. These findings underscore the promise of CMA2 administration as an effective therapeutic strategy for enhancing metabolic parameters and cognitive function in AD and PD patients.

Effect of parenteral L-carnitine in hospitalized patients with moderate to severe COVID-19: A randomized double-blind clinical trial

Introduction

Pro-inflammatory responses have an important role in developing coronavirus disease 2019 (COVID-19). L-carnitine (LC) has been known to possess anti-inflammatory, anticoagulant, and antiviral effects. So, we aimed to evaluate the efficacy of LC in hospitalized patients with moderate-to-severe COVID-19.

Methods

This double-blind, placebo-controlled, randomized clinical trial was conducted on hospitalized patients with moderate to severe COVID-19. The patients were randomized (1:1) to receive LC (n = 50) at a dose of 20 mg/kg or matching placebo (n = 51) from normal saline once daily for 14 days or until hospitalization and standard care. The primary outcome was hospital mortality and disease severity according to the World Health Organization's clinical progression scale. We also assessed the free carnitine level at baseline and the end of the study. C-reactive protein (CRP), ferritin, D-dimer, lactate dehydrogenase (LDH), and improvement of respiratory conditions were chosen as secondary outcomes.

Results

From 104 patients who met the inclusion criteria, 101 individuals' data were analyzed. The LC group showed a significant reduction in LDH levels (P = 0.003), although CRP, ferritin, and D-dimer levels did not significantly differ from the placebo group. Also, no significant difference was observed in disease severity, oxygenation status, hospital mortality, or hospital stay between the two groups. Additionally, there was no increase in serum-free carnitine levels in the LC group (P > 0.05 for all).

Conclusion

The results of the current study did not support the superiority of LC over placebo in improving oxygenation, decreasing mortality, and hospital stay, as well as CRP, ferritin, and D-dimer in moderate to severe COVID-19 patients.

Trial Registration

IRCT20170609034406N10; https://en.irct.ir/trial/60306.

Low-dose naltrexone and NAD+ for the treatment of patients with persistent fatigue symptoms after COVID-19

A subset of patients experiences persistent fatigue symptoms after COVID-19, and patients may develop long COVID, which is characterized by lasting systemic symptoms. No treatments for this condition have been validated and are urgently warranted. In this pilot study, we assessed whether treatment with low-dose naltrexone (LDN, 4.5 mg/day) and supplementation with NAD + through iontophoresis patches could improve fatigue symptoms and quality of life in 36 patients with persistent moderate/severe fatigue after COVID-19. We detected a significant increase from baseline in SF-36 survey scores after 12 weeks of treatment (mean total SF-36 score 36.5 [SD: 15.6] vs. 52.1 [24.8]; p < 0.0001), suggestive of improvement of quality of life. Furthermore, participants scored significantly lower on the Chalder fatigue scale after 12 weeks of treatment (baseline: 25.9 [4.6], 12 weeks: 17.4 [9.7]; p < 0.0001). We found a subset of 52 % of patients to be responders after 12 weeks of treatment. Treatment was generally safe, with mild adverse events previously reported for LDN, which could be managed with dose adjustments. The iontophoresis patches were associated with mild, short-lived skin irritation in 25 % of patients. Our data suggest treatment with LDN and NAD+ is safe and may be beneficial in a subset of patients with persistent fatigue after COVID-19. Larger randomized controlled trials will have to confirm our data and determine which patient subpopulations might benefit most from this strategy.

Novel antioxidant protein target therapy to counter the prevalence and severity of SARS-CoV-2

Background

This review analyzed the magnitude of the COVID-19 pandemic globally and in India and the measures to counter its effect using natural and innate immune booster molecules. The study focuses on two phases: the first focuses on the magnitude, and the second on the effect of antioxidants (natural compounds) on SARS-CoV-2.

Methods

The magnitude of the prevalence, mortality, and comorbidities was acquired from the World Health Organization (WHO) report, media, a report from the Ministry of Health and Family Welfare (MoHFW), newspapers, and the National Centre of Disease Control (NCDC). Research articles from PubMed as well as other sites/journals and databases were accessed to gather literature on the effect of antioxidants.

Results

In the elderly and any chronic diseases, the declined level of antioxidant molecules enhanced the reactive oxygen species, which in turn deprived the immune system.

Conclusion

Innate antioxidant proteins like sirtuin and sestrin play a vital role in enhancing immunity. Herbal products and holistic approaches can also be alternative solutions for everyday life to boost the immune system by improving the redox balance in COVID-19 attack. This review analyzed the counteractive effect of alternative therapy to boost the immune system against the magnitude of the COVID-19 pandemic.

Drug Synergism of Anticancer Action in Combination with Favipiravir and Paclitaxel on Neuroblastoma Cells

Background and Objectives: Favipiravir (FPV) is an antiviral medication and has an inhibitory effect on Cytochrome P450 (CYP2C8) protein, which is mainly involved in drug metabolism in the liver, and the expression of this gene is known to be enhanced in neuronal cells. The metabolization of Paclitaxel (PTX), a chemotherapeutic drug used in cancer patients, was analyzed for the first time in the human SH-SY5Y neuroblastoma cell line for monitoring possible synergistic effects when administered with FPV. Materials and Methods: Further, in vitro cytotoxic and genotoxic evaluations of FPV and PTX were also performed using wide concentration ranges in a human fibroblast cell culture (HDFa). Nuclear abnormalities were examined under a fluorescent microscope using the Hoechst 33258 fluorescent staining technique. In addition, the synergistic effects of these two drugs on cultured SH-SY5Y cells were determined by MTT cell viability assay. In addition, the death mechanisms that can occur in SHSY-5Y were revealed by using the flow cytometry technique. Results: Cell viability analyses on the HDFa healthy cell culture showed that both FPV and PTX have inhibitory effects at higher concentrations. On the other hand, there were no significant differences in nuclear abnormality numbers when both of the compounds were applied together. Cell viability analyses showed that FPV and PTX applications have higher cytotoxicity, which indicated synergistic toxicity against the SHSY-5Y cell line. Also, PTX exhibited higher anticancer properties against the neuroblastoma cell line when applied with FPV, as shown in both cytotoxicity and flow cytometry analyses. Conclusions: In light of our findings, the anticancer properties of PTX can be enhanced when the drug application is coupled with FPV exposure. Moreover, these results put forth that the anticancer drug dosage should be evaluated carefully in cancer patients who take COVID-19 treatment with FPV.

Dietary Supplementation With NAD+-Boosting Compounds in Humans: Current Knowledge and Future Directions

Advancing age and many disease states are associated with declines in nicotinamide adenine dinucleotide (NAD+) levels. Preclinical studies suggest that boosting NAD+ abundance with precursor compounds, such as nicotinamide riboside or nicotinamide mononucleotide, has profound effects on physiological function in models of aging and disease. Translation of these compounds for oral supplementation in humans has been increasingly studied within the last 10 years; however, the clinical evidence that raising NAD+ concentrations can improve physiological function is unclear. The goal of this review was to synthesize the published literature on the effects of chronic oral supplementation with NAD+ precursors on healthy aging and age-related chronic diseases. We identified nicotinamide riboside, nicotinamide riboside co-administered with pterostilbene, and nicotinamide mononucleotide as the most common candidates in investigations of NAD+-boosting compounds for improving physiological function in humans. Studies have been performed in generally healthy midlife and older adults, adults with cardiometabolic disease risk factors such as overweight and obesity, and numerous patient populations. Supplementation with these compounds is safe, tolerable, and can increase the abundance of NAD+ and related metabolites in multiple tissues. Dosing regimens and study durations vary greatly across interventions, and small sample sizes limit data interpretation of physiological outcomes. Limitations are identified and future research directions are suggested to further our understanding of the potential efficacy of NAD+-boosting compounds for improving physiological function and extending human health span.

NAD+ Precursors in Human Health and Disease: Current Status and Future Prospects

Significance: Nicotinamide adenine dinucleotide (NAD+) acts as a cofactor in many important biological processes. The administration of NAD+ precursors increases the intracellular NAD+ pool and has beneficial effects on physiological changes and diseases associated with aging in various organisms, including rodents and humans. Recent Advances: Evidence from preclinical studies demonstrating the beneficial effects of NAD+ precursors has rapidly increased in the last decade. The results of these studies have prompted the development of clinical trials using NAD+ precursors, particularly nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). In addition, in vivo studies of NAD+ metabolism have rapidly progressed. Critical Issues: Several studies have demonstrated that the oral administration of NAD+ precursors, such as NR and NMN, is safe and significantly increases NAD+ levels in humans. However, the efficacy of these NAD+ precursors is lower than expected from the results of preclinical studies. In addition, the identification of the contribution of the host-gut microbiota interactions to NR and NMN metabolism has added to the complexity of NAD+ metabolism. Future Directions: Further studies are required to determine the efficacy of NAD+ precursors in humans. Further in vivo studies of NAD+ metabolism are required to optimize the effects of NAD+ supplementation. There is also a need for methods of delivering NAD+ precursors to target organs or tissues to increase the outcomes of clinical trials. Antioxid. Redox Signal. 39, 1133-1149.

Nicotinamide Adenine Dinucleotide in Aging Biology: Potential Applications and Many Unknowns

Recent research has unveiled an expansive role of NAD+ in cellular energy generation, redox reactions, and as a substrate or cosubstrate in signaling pathways that regulate health span and aging. This review provides a critical appraisal of the clinical pharmacology and the preclinical and clinical evidence for therapeutic effects of NAD+ precursors for age-related conditions, with a particular focus on cardiometabolic disorders, and discusses gaps in current knowledge. NAD+ levels decrease throughout life; age-related decline in NAD+ bioavailability has been postulated to be a contributor to many age-related diseases. Raising NAD+ levels in model organisms by administration of NAD+ precursors improves glucose and lipid metabolism; attenuates diet-induced weight gain, diabetes, diabetic kidney disease, and hepatic steatosis; reduces endothelial dysfunction; protects heart from ischemic injury; improves left ventricular function in models of heart failure; attenuates cerebrovascular and neurodegenerative disorders; and increases health span. Early human studies show that NAD+ levels can be raised safely in blood and some tissues by oral NAD+ precursors and suggest benefit in preventing nonmelanotic skin cancer, modestly reducing blood pressure and improving lipid profile in older adults with obesity or overweight; preventing kidney injury in at-risk patients; and suppressing inflammation in Parkinson disease and SARS-CoV-2 infection. Clinical pharmacology, metabolism, and therapeutic mechanisms of NAD+ precursors remain incompletely understood. We suggest that these early findings provide the rationale for adequately powered randomized trials to evaluate the efficacy of NAD+ augmentation as a therapeutic strategy to prevent and treat metabolic disorders and age-related conditions.

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

SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), induces vascular endothelial dysfunction, but the mechanisms are unknown. We tested the hypothesis that the "circulating milieu" (plasma) of patients with COVID-19 would cause endothelial cell dysfunction (characterized by lower nitric oxide (NO) production), which would be linked to greater reactive oxygen species (ROS) bioactivity and depletion of the critical metabolic co-substrate, nicotinamide adenine dinucleotide (NAD+). We also investigated if treatment with NAD+-boosting compounds would prevent COVID-19-induced reductions in endothelial cell NO bioavailability and oxidative stress. Human aortic endothelial cells (HAECs) were exposed to plasma from men and women (age 18-85 years) who were hospitalized and tested positive (n = 34; 20 M) or negative (n = 13; 10 M) for COVID-19. HAECs exposed to plasma from patients with COVID-19 also were co-incubated with NAD+ precursors nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN). Acetylcholine-stimulated NO production was 27% lower and ROS bioactivity was 54% higher in HAECs exposed to plasma from patients with COVID-19 (both p < 0.001 vs. control); these responses were independent of age and sex. NAD+ concentrations were 30% lower in HAECs exposed to plasma from patients with COVID-19 (p = 0.001 vs. control). Co-incubation with NR abolished COVID-19-induced reductions in NO production and oxidative stress (both p > 0.05 vs. control). Co-treatment with NMN produced similar results. Our findings suggest the circulating milieu of patients with COVID-19 promotes endothelial cell dysfunction, characterized by lower NO bioavailability, greater ROS bioactivity, and NAD+ depletion. Supplementation with NAD+ precursors may exert a protective effect against COVID-19-evoked endothelial cell dysfunction and oxidative stress.

Total network controllability analysis discovers explainable drugs for Covid-19 treatment

BACKGROUND

The active pursuit of network medicine for drug repurposing, particularly for combating Covid-19, has stimulated interest in the concept of structural controllability in cellular networks. We sought to extend this theory, focusing on the defense rather than control of the cell against viral infections. Accordingly, we extended structural controllability to total structural controllability and introduced the concept of control hubs. Perturbing any control hub may render the cell uncontrollable by exogenous stimuli like viral infections, so control hubs are ideal drug targets.

RESULTS

We developed an efficient algorithm to identify all control hubs, applying it to a largest homogeneous network of human protein interactions, including interactions between human and SARS-CoV-2 proteins. Our method recognized 65 druggable control hubs with enriched antiviral functions. Utilizing these hubs, we categorized potential drugs into four groups: antiviral and anti-inflammatory agents, drugs acting on the central nervous system, dietary supplements, and compounds enhancing immunity. An exemplification of our approach's effectiveness, Fostamatinib, a drug initially developed for chronic immune thrombocytopenia, is now in clinical trials for treating Covid-19. Preclinical trial data demonstrated that Fostamatinib could reduce mortality rates, ICU stay length, and disease severity in Covid-19 patients.

CONCLUSIONS

Our findings confirm the efficacy of our novel strategy that leverages control hubs as drug targets. This approach provides insights into the molecular mechanisms of potential therapeutics for Covid-19, making it a valuable tool for interpretable drug discovery. Our new approach is general and applicable to repurposing drugs for other diseases.

NAD+ Precursors Nicotinamide Mononucleotide (NMN) and Nicotinamide Riboside (NR): Potential Dietary Contribution to Health

PURPOSE OF REVIEW

NAD+ is a vital molecule that takes part as a redox cofactor in several metabolic reactions besides being used as a substrate in important cellular signaling in regulation pathways for energetic, genotoxic, and infectious stress. In stress conditions, NAD+ biosynthesis and levels decrease as well as the activity of consuming enzymes rises. Dietary precursors can promote NAD+ biosynthesis and increase intracellular levels, being a potential strategy for reversing physiological decline and preventing diseases. In this review, we will show the biochemistry and metabolism of NAD+ precursors NR (nicotinamide riboside) and NMN (nicotinamide mononucleotide), the latest findings on their beneficial physiological effects, their interplay with gut microbiota, and the future perspectives for research in nutrition and food science fields.

RECENT FINDINGS

NMN and NR demonstrated protect against diabetes, Alzheimer disease, endothelial dysfunction, and inflammation. They also reverse gut dysbiosis and promote beneficial effects at intestinal and extraintestinal levels. NR and NMN have been found in vegetables, meat, and milk, and microorganisms in fermented beverages can also produce them. NMN and NR can be obtained through the diet either in their free form or as metabolites derivate from the digestion of NAD+. The prospection of NR and NMN to find potential food sources and their dietary contribution in increasing NAD+ levels are still an unexplored field of research. Moreover, it could enable the development of new functional foods and processing strategies to maintain and enhance their physiological benefits, besides the studies of new raw materials for extraction and biotechnological development.

The kynurenine pathway of tryptophan metabolism: a neglected therapeutic target of COVID-19 pathophysiology and immunotherapy

SARS-CoV-2 (COVID-19) exerts profound changes in the kynurenine (Kyn) pathway (KP) of tryptophan (Trp) metabolism that may underpin its pathophysiology. The KP is the main source of the vital cellular effector NAD+ and intermediate metabolites that modulate immune and neuronal functions. Trp metabolism is the top pathway influenced by COVID-19. Sixteen studies established virus-induced activation of the KP mediated mainly by induction of indoleamine 2,3-dioxygenase (IDO1) in most affected tissues and of IDO2 in lung by the increased release of proinflammatory cytokines but could additionally involve increased flux of plasma free Trp and induction of Trp 2,3-dioxygenase (TDO) by cortisol. The major Kyn metabolite targeted by COVID-19 is kynurenic acid (KA), the Kyn metabolite with the greatest affinity for the aryl hydrocarbon receptor (AhR), which is also activated by COVID-19. AhR activation initiates two important series of events: a vicious circle involving IDO1 induction, KA accumulation and further AhR activation, and activation of poly (ADP-ribose) polymerase (PARP) leading to NAD+ depletion and cell death. The virus further deprives the host of NAD+ by inhibiting its main biosynthetic pathway from quinolinic acid, while simultaneously acquiring NAD+ by promoting its synthesis from nicotinamide in the salvage pathway. Additionally, the protective effects of sirtuin 1 are minimised by the PARP activation. KP dysfunction may also underpin the mood and neurological disorders acutely and during 'long COVID'. More studies of potential effects of vaccination therapy on the KP are required and exploration of therapeutic strategies involving modulation of the KP changes are proposed.

The acute effect of different NAD+ precursors included in the combined metabolic activators

NAD+ and glutathione precursors are currently used as metabolic modulators for improving the metabolic conditions associated with various human diseases, including non-alcoholic fatty liver disease, neurodegenerative diseases, mitochondrial myopathy, and age-induced diabetes. Here, we performed a one-day double blinded, placebo-controlled human clinical study to assess the safety and acute effects of six different Combined Metabolic Activators (CMAs) with 1 g of different NAD+ precursors based on global metabolomics analysis. Our integrative analysis showed that the NAD+ salvage pathway is the main source for boosting the NAD+ levels with the administration of CMAs without NAD+ precursors. We observed that incorporation of nicotinamide (Nam) in the CMAs can boost the NAD+ products, followed by niacin (NA), nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), but not flush free niacin (FFN). In addition, the NA administration led to a flushing reaction, accompanied by decreased phospholipids and increased bilirubin and bilirubin derivatives, which could be potentially risky. In conclusion, this study provided a plasma metabolomic landscape of different CMA formulations, and proposed that CMAs with Nam, NMN as well as NR can be administered for boosting NAD+ levels to improve altered metabolic conditions.

What is really known about the effects of nicotinamide riboside supplementation in humans

Nicotinamide riboside is a precursor to the important cofactor nicotinamide adenine dinucleotide and has elicited metabolic benefits in multiple preclinical studies. In 2016, the first clinical trial of nicotinamide riboside was conducted to test the safety and efficacy of human supplementation. Many trials have since been conducted aiming to delineate benefits to metabolic health and severe diseases in humans. This review endeavors to summarize and critically assess the 25 currently published research articles on human nicotinamide riboside supplementation to identify any poorly founded claims and assist the field in elucidating the actual future potential for nicotinamide riboside. Collectively, oral nicotinamide riboside supplementation has displayed few clinically relevant effects, and there is an unfortunate tendency in the literature to exaggerate the importance and robustness of reported effects. Even so, nicotinamide riboside may play a role in the reduction of inflammatory states and has shown some potential in the treatment of diverse severe diseases.

A randomized clinical trial to evaluate the efficacy of L-carnitine L-tartrate to modulate the effects of SARS-CoV-2 infection

Introduction

L-carnitine (LC) has been associated with inflammatory mediator reduction and with downregulating the angiotensin-converting enzyme-2 (ACE2) receptor, which is the target of SARS-CoV-2 attachment.

Methods

This pilot phase 2 randomized, double-blind placebo-controlled trial contained two cohorts. Cohort 1 comprised 101 individuals with negative RT-PCR SARS-CoV-2 test results who cohabitated with an individual diagnosed with SARS-CoV-2 infection. Cohort 2 comprised 122 individuals with positive SARS-CoV-2 RT-PCR test results who were asymptomatic or had mild COVID-19 pneumonia symptoms. Participants in each cohort were randomized 1:1 to receive either 2 g elemental oral LC supplementation or placebo daily for 21 days. Primary endpoints included adverse events, SARS-CoV-2 infection incidence in Cohort 1, and disease progressions in Cohort 2. Secondary endpoints included between-group laboratory profile comparisons and Cohort 2 ACE1/ACE2 plasma levels. Disease progression was compared between the Cohort 2 groups using chest computed tomography.

Results

In Cohort 1, two SARS-CoV-2 infections occurred in each group. The common adverse events included headache, dyspnea, and tiredness. In Cohort 2, platelet counts were elevated, and fibrinogen levels reduced in the LC group compared with those of the placebo group.

Conclusion

Our study showed that LC was well-tolerated and suggests it modulates coagulation pathways. Furthermore, chest computed tomography images of the Cohort 2 LC group showed significant lung lesion improvement, suggesting that LC may slow COVID-19 progression.

Total network controllability analysis discovers explainable drugs for Covid-19 treatment

Background The active pursuit of network medicine for drug repurposing, particularly for combating Covid-19, has stimulated interest in the concept of structural control capability in cellular networks. We sought to extend this theory, focusing on the defense rather than control of the cell against viral infections. Accordingly, we extended structural controllability to total structural controllability and introduced the concept of control hubs. Perturbing any control hub may render the cell uncontrollable by exogenous stimuli like viral infections, so control hubs are ideal drug targets. Results We developed an efficient algorithm to identify all control hubs, applying it to the largest homogeneous network of human protein interactions, including interactions between human and SARS-CoV-2 proteins. Our method recognized 65 druggable control hubs with enriched antiviral functions. Utilizing these hubs, we categorized potential drugs into four groups: antiviral and anti-inflammatory agents, drugs acting on the central nervous system, dietary supplements, and compounds enhancing immunity. An exemplification of our approach's effectiveness, Fostamatinib, a drug initially developed for chronic immune thrombocytopenia, is now in clinical trials for treating Covid-19. Preclinical trial data demonstrated that Fostamatinib could reduce mortality rates, ICU stay length, and disease severity in Covid-19 patients. Conclusions Our findings confirm the efficacy of our novel strategy that leverages control hubs as drug targets. This approach provides insights into the molecular mechanisms of potential therapeutics for Covid-19, making it a valuable tool for interpretable drug discovery.

NAD+ Metabolism and Immune Regulation: New Approaches to Inflammatory Bowel Disease Therapies

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is a multifactorial systemic inflammatory immune response. Nicotinamide adenine dinucleotide (NAD⁺) is a co-enzyme involved in cell signaling and energy metabolism. Calcium homeostasis, gene transcription, DNA repair, and cell communication involve NAD⁺ and its degradation products. There is a growing recognition of the intricate relationship between inflammatory diseases and NAD⁺ metabolism. In the case of IBD, the maintenance of intestinal homeostasis relies on a delicate balance between NAD⁺ biosynthesis and consumption. Consequently, therapeutics designed to target the NAD⁺ pathway are promising for the management of IBD. This review discusses the metabolic and immunoregulatory processes of NAD⁺ in IBD to examine the molecular biology and pathophysiology of the immune regulation of IBD and to provide evidence and theoretical support for the clinical use of NAD⁺ in IBD.

Therapeutic application of natural products: NAD+ metabolism as potential target

BACKGROUND

Nicotinamide adenine dinucleotide (NAD⁺) metabolism is involved in the entire physiopathological process and is critical to human health. Long-term imbalance in NAD⁺ homeostasis is associated with various diseases, including non-alcoholic fatty liver disease, diabetes mellitus, cardiovascular diseases, neurodegenerative disorders, aging, and cancer, making it a potential target for effective therapeutic strategies. Currently, several natural products that target NAD⁺ metabolism have been widely reported to have significant therapeutic effects, but systematic summaries are lacking.

PURPOSE

To summarize the latest findings on the prevention and treatment of various diseases through the regulation of NAD⁺ metabolism by various natural products in vivo and in vitro models, and evaluate the toxicities of the natural products.

METHODS

PubMed, Web of Science, and ScienceDirect were searched using the keywords "natural products sources," "toxicology," "NAD⁺ clinical trials," and "NAD⁺," and/or paired with "natural products" and "diseases" for studies published within the last decade until January 2023.

RESULTS

We found that the natural products mainly include phenols (curcumin, cyclocurcumin, 4-hydroxybenzyl alcohol, salvianolic acid B, pterostilbene, EGCG), flavonoids (pinostrobin, apigenin, acacetin, tilianin, kaempferol, quercetin, isoliquiritigenin, luteolin, silybin, hydroxysafflor yellow A, scutellarin), glycosides (salidroside), quinones (emodin, embelin, β-LAPachone, shikonin), terpenoids (notoginsenoside R1, ginsenoside F2, ginsenoside Rd, ginsenoside Rb1, ginsenoside Rg3, thymoquinone, genipin), pyrazines (tetramethylpyrazine), alkaloids (evodiamine, berberine), and phenylpropanoids (ferulic acid). These natural products have antioxidant, energy-producing, anti-inflammatory, anti-apoptotic and anti-aging effects, which mainly influence the NAMPT/NAD⁺/SIRT, AMPK/SIRT1/PGC-1α, Nrf2/HO-1, PKCs/PARPs/NF-κB, and AMPK/Nrf2/mTOR signaling pathways, thereby regulating NAD⁺ metabolism to prevent and treat various diseases. These natural products have been shown to be safe, tolerable and have fewer adverse effects in various in vivo and in vitro studies and clinical trials.

CONCLUSION

We evaluated the toxic effects of natural products and summarized the available clinical trials on NAD⁺ metabolism, as well as the recent advances in the therapeutic application of natural products targeting NAD⁺ metabolism, with the aim to provide new insights into the treatment of multiple disorders.

Ketogenic Diet and Ketone Bodies as Clinical Support for the Treatment of SARS-CoV-2-Review of the Evidence

One of the proposed nutritional therapies to support drug therapy in COVID-19 is the use of a ketogenic diet (KD) or ketone bodies. In this review, we summarized the evidence from tissue, animal, and human models and looked at the mechanisms of action of KD/ketone bodies against COVID-19. KD/ketone bodies were shown to be effective at the stage of virus entry into the host cell. The use of β-hydroxybutyrate (BHB), by preventing the metabolic reprogramming associated with COVID-19 infection and improving mitochondrial function, reduced glycolysis in CD4+ lymphocytes and improved respiratory chain function, and could provide an alternative carbon source for oxidative phosphorylation (OXPHOS). Through multiple mechanisms, the use of KD/ketone bodies supported the host immune response. In animal models, KD resulted in protection against weight loss and hypoxemia, faster recovery, reduced lung injury, and resulted in better survival of young mice. In humans, KD increased survival, reduced the need for hospitalization for COVID-19, and showed a protective role against metabolic abnormalities after COVID-19. It appears that the use of KD and ketone bodies may be considered as a clinical nutritional intervention to assist in the treatment of COVID-19, despite the fact that numerous studies indicate that SARS-CoV-2 infection alone may induce ketoacidosis. However, the use of such an intervention requires strong scientific validation.

Longitudinal metabolomics analysis reveals the acute effect of cysteine and NAC included in the combined metabolic activators

Growing evidence suggests that the depletion of plasma NAD⁺ and glutathione (GSH) may play an important role in the development of metabolic disorders. The administration of Combined Metabolic Activators (CMA), consisting of GSH and NAD⁺ precursors, has been explored as a promising therapeutic strategy to target multiple altered pathways associated with the pathogenesis of the diseases. Although studies have examined the therapeutic effect of CMA that contains N-acetyl-l-cysteine (NAC) as a metabolic activator, a system-wide comparison of the metabolic response to the administration of CMA with NAC and cysteine remains lacking. In this placebo-controlled study, we studied the acute effect of the CMA administration with different metabolic activators, including NAC or cysteine with/without nicotinamide or flush free niacin, and performed longitudinal untargeted-metabolomics profiling of plasma obtained from 70 well-characterized healthy volunteers. The time-series metabolomics data revealed the metabolic pathways affected after the administration of CMAs showed high similarity between CMA containing nicotinamide and NAC or cysteine as metabolic activators. Our analysis also showed that CMA with cysteine is well-tolerated and safe in healthy individuals throughout the study. Last, our study systematically provided insights into a complex and dynamics landscape involved in amino acid, lipid and nicotinamide metabolism, reflecting the metabolic responses to CMA administration containing different metabolic activators.

NAD+ metabolism-based immunoregulation and therapeutic potential

Nicotinamide adenine dinucleotide (NAD⁺) is a critical metabolite that acts as a cofactor in energy metabolism, and serves as a cosubstrate for non-redox NAD⁺-dependent enzymes, including sirtuins, CD38 and poly(ADP-ribose) polymerases. NAD⁺ metabolism can regulate functionality attributes of innate and adaptive immune cells and contribute to inflammatory responses. Thus, the manipulation of NAD⁺ bioavailability can reshape the courses of immunological diseases. Here, we review the basics of NAD⁺ biochemistry and its roles in the immune response, and discuss current challenges and the future translational potential of NAD⁺ research in the development of therapeutics for inflammatory diseases, such as COVID-19.

2023 Chinese expert consensus on the impact of COVID-19 on the management of cardiovascular diseases

The primary site of infection in COVID-19 exhibit is the respiratory system, but multiple organ systems could be affected. The virus could directly invade cardiomyocytes. Alternatively, cytokine storm could lead to myocardial injury. More importantly, the management of existing cardiovascular diseases must be re-examined in COVID-19 due to, for example, interaction between antiviral agents and with a wide variety of pharmacological agents. The Branch of Cardiovascular Physicians of Chinese Medical Doctor Association organized a panel of experts in cardiovascular and related fields to discuss this important issue, and formulated the "2023 Chinese Expert Consensus on the Impact of COVID-19 on the Management of Cardiovascular Diseases." The Consensus was drafted on the basis of systematic review of existing evidence and diagnosis and treatment experience, and covers three major aspects: myocardial injury caused by COVID-10 and COVID-19 vaccine, the impact of COVID-19 on patients with cardiovascular disease, and the impact of COVID-19 on the cardiovascular system of healthy people, and rehabilitation guidance recommendations. The Consensus involves 11 core clinical issues, including incidence, pathogenesis, clinical manifestations, treatment strategies, prognosis, and rehabilitation. It is our hope that this Consensus will provide a practical guidance to cardiologists in the management of cardiovascular diseases in the new era of COVID-19 pandemic.

Analysis of temporal metabolic rewiring for human respiratory syncytial virus infection by integrating metabolomics and proteomics

INTRODUCTION

Human respiratory syncytial virus (HRSV) infection causes significant morbidity, and no effective treatments are currently available. Viral infections induce substantial metabolic changes in the infected cells to optimize viral production. Metabolites that reflect the interactions between host cells and viruses provided an opportunity to identify the pathways underlying severe infections.

OBJECTIVE

To better understand the metabolic changes caused by HRSV infection, we analyzed temporal metabolic profiling to provide novel targets for therapeutic strategies for inhaled HRSV infection.

METHODS

The epithelial cells and BALB/c mice were infected with HRSV. Protein and mRNA levels of inflammation factors were measured by using quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Untargeted metabolomics, lipidomics and proteomics were performed using liquid chromatography coupled with mass spectrometry to profile the metabolic phenotypic alterations in HRSV infection.

RESULTS

In this study, we evaluated the inflammatory responses in vivo and in vitro and investigated the temporal metabolic rewiring of HRSV infection in epithelial cells. We combined metabolomics and proteomic analyses to demonstrate that the redox imbalance was further provoked by increasing glycolysis and anaplerotic reactions. These responses created an oxidant-rich microenvironment that elevated reactive oxygen species levels and exacerbated glutathione consumption.

CONCLUSION

These observations indicate that adjusting for metabolic events during a viral infection could represent a valuable approach for reshaping the outcome of infections.

Combined metabolic activators improve cognitive functions in Alzheimer's disease patients: a randomised, double-blinded, placebo-controlled phase-II trial

BACKGROUND

Alzheimer's disease (AD) is associated with metabolic abnormalities linked to critical elements of neurodegeneration. We recently administered combined metabolic activators (CMA) to the AD rat model and observed that CMA improves the AD-associated histological parameters in the animals. CMA promotes mitochondrial fatty acid uptake from the cytosol, facilitates fatty acid oxidation in the mitochondria, and alleviates oxidative stress.

METHODS

Here, we designed a randomised, double-blinded, placebo-controlled phase-II clinical trial and studied the effect of CMA administration on the global metabolism of AD patients. One-dose CMA included 12.35 g L-serine (61.75%), 1 g nicotinamide riboside (5%), 2.55 g N-acetyl-L-cysteine (12.75%), and 3.73 g L-carnitine tartrate (18.65%). AD patients received one dose of CMA or placebo daily during the first 28 days and twice daily between day 28 and day 84. The primary endpoint was the difference in the cognitive function and daily living activity scores between the placebo and the treatment arms. The secondary aim of this study was to evaluate the safety and tolerability of CMA. A comprehensive plasma metabolome and proteome analysis was also performed to evaluate the efficacy of the CMA in AD patients.

RESULTS

We showed a significant decrease of AD Assessment Scale-cognitive subscale (ADAS-Cog) score on day 84 vs day 0 (P = 0.00001, 29% improvement) in the CMA group. Moreover, there was a significant decline (P = 0.0073) in ADAS-Cog scores (improvement of cognitive functions) in the CMA compared to the placebo group in patients with higher ADAS-Cog scores. Improved cognitive functions in AD patients were supported by the relevant alterations in the hippocampal volumes and cortical thickness based on imaging analysis. Moreover, the plasma levels of proteins and metabolites associated with NAD + and glutathione metabolism were significantly improved after CMA treatment.

CONCLUSION

Our results indicate that treatment of AD patients with CMA can lead to enhanced cognitive functions and improved clinical parameters associated with phenomics, metabolomics, proteomics and imaging analysis. Trial registration ClinicalTrials.gov NCT04044131 Registered 17 July 2019, https://clinicaltrials.gov/ct2/show/NCT04044131.

Evaluation the efficacy and safety of N-acetylcysteine inhalation spray in controlling the symptoms of patients with COVID-19: An open-label randomized controlled clinical trial

The aim of this study was to evaluate the effect and safety of N-acetylcysteine (NAC) inhalation spray in the treatment of patients with coronavirus disease 2019 (COVID-19). This randomized controlled clinical trial study was conducted on patients with COVID-19. Eligible patients (n = 250) were randomly allocated into the intervention group (routine treatment + NAC inhaler spray one puff per 12 h, for 7 days) or the control group who received routine treatment alone. Clinical features, hemodynamic, hematological, biochemical parameters and patient outcomes were assessed and compared before and after treatment. The mortality rate was significantly higher in the control group than in the intervention group (39.2% vs. 3.2%, p < 0.001). Significant differences were found between the two groups (intervention and control, respectively) for white blood cell count (6.2 vs. 7.8, p < 0.001), hemoglobin (12.3 vs. 13.3, p = 0.002), C-reactive protein (CRP: 6 vs. 11.5, p < 0.0001) and aspartate aminotransferase (AST: 32 vs. 25.5, p < 0.0001). No differences were seen for hospital length of stay (11.98 ± 3.61 vs. 11.81 ± 3.52, p = 0.814) or the requirement for intensive care unit (ICU) admission (7.2% vs. 11.2%, p = 0.274). NAC was beneficial in reducing the mortality rate in patients with COVID-19 and inflammatory parameters, and a reduction in the development of severe respiratory failure; however, it did not affect the length of hospital stay or the need for ICU admission. Data on the effectiveness of NAC for Severe Acute Respiratory Syndrome Coronavirus-2 is limited and further research is required.

Proteomic Investigation of COVID-19 Severity During the Tsunamic Second Wave in Mumbai

Maharashtra was severely affected during the noxious second wave of COVID-19, with the highest number of cases recorded across India. The emergence of new symptoms and dysregulation of multiple organs resulted in high disease severity during the second wave which led to increased difficulties in understanding the molecular mechanisms behind the disease pathology. Exploring the underlying factors can help to relieve the burden on the medical communities to some extent by prioritizing the patients and, at the same time, opening avenues for improved treatments. In the current study, we have performed a mass-spectrometry-based proteomic analysis to investigate the disease pathology using nasopharyngeal swab samples collected from the COVID-19 patients in the Mumbai region of Maharashtra over the period of March-June 2021, the peak of the second wave. A total of 59 patients, including 32 non-severe and 27 severe cases, were considered for this proteomic study. We identified 23 differentially regulated proteins in severe patients as a host response to infection. In addition to the previously identified innate mechanisms of neutrophil and platelet degranulation, this study revealed significant alterations of anti-microbial peptide pathways in severe conditions, illustrating its role in the severity of the infectious strain of COVID-19 during the second wave. Furthermore, myeloperoxidase, cathepsin G, and profilin-1 were identified as potential therapeutic targets of the FDA-approved drugs dabrafenib, ZINC4097343, and ritonavir. This study has enlightened the role of the anti-microbial peptide pathway associated with the second wave in India and proposed its importance in potential therapeutics for COVID-19.

Alterations in the Kynurenine-Tryptophan Pathway and Lipid Dysregulation Are Preserved Features of COVID-19 in Hemodialysis

Coronavirus disease 2019 (COVID-19)-induced metabolic alterations have been proposed as a source for prognostic biomarkers and may harbor potential for therapeutic exploitation. However, the metabolic impact of COVID-19 in hemodialysis (HD), a setting of profound a priori alterations, remains unstudied. To evaluate potential COVID-19 biomarkers in end-stage kidney disease (CKD G5), we analyzed the plasma metabolites in different COVID-19 stages in patients with or without HD. We recruited 18 and 9 asymptomatic and mild, 11 and 11 moderate, 2 and 13 severely affected, and 10 and 6 uninfected HD and non-HD patients, respectively. Plasma samples were taken at the time of diagnosis and/or upon admission to the hospital and analyzed by targeted metabolomics and cytokine/chemokine profiling. Targeted metabolomics confirmed stage-dependent alterations of the metabolome in non-HD patients with COVID-19, which were less pronounced in HD patients. Elevated kynurenine levels and lipid dysregulation, shown by an increase in circulating free fatty acids and a decrease in lysophospholipids, could distinguish patients with moderate COVID-19 from non-infected individuals in both groups. Kynurenine and lipid alterations were also associated with ICAM-1 and IL-15 levels in HD and non-HD patients. Our findings support the kynurenine pathway and plasma lipids as universal biomarkers of moderate and severe COVID-19 independent of kidney function.

Urine Metabolites Enable Fast Detection of COVID-19 Using Mass Spectrometry

The COVID-19 pandemic boosted the development of diagnostic tests to meet patient needs and provide accurate, sensitive, and fast disease detection. Despite rapid advancements, limitations related to turnaround time, varying performance metrics due to different sampling sites, illness duration, co-infections, and the need for particular reagents still exist. As an alternative diagnostic test, we present urine analysis through flow-injection-tandem mass spectrometry (FIA-MS/MS) as a powerful approach for COVID-19 diagnosis, targeting the detection of amino acids and acylcarnitines. We adapted a method that is widely used for newborn screening tests on dried blood for urine samples in order to detect metabolites related to COVID-19 infection. We analyzed samples from 246 volunteers with diagnostic confirmation via PCR. Urine samples were self-collected, diluted, and analyzed with a run time of 4 min. A Lasso statistical classifier was built using 75/25% data for training/validation sets and achieved high diagnostic performances: 97/90% sensitivity, 95/100% specificity, and 95/97.2% accuracy. Additionally, we predicted on two withheld sets composed of suspected hospitalized/symptomatic COVID-19-PCR negative patients and patients out of the optimal time-frame collection for PCR diagnosis, with promising results. Altogether, we show that the benchmarked FIA-MS/MS method is promising for COVID-19 screening and diagnosis, and is also potentially useful after the peak viral load has passed.

Metabolomics analysis identifies glutamic acid and cystine imbalances in COVID-19 patients without comorbid conditions. Implications on redox homeostasis and COVID-19 pathophysiology

It is well known that the presence of comorbidities and age-related health issues may hide biochemical and metabolic features triggered by SARS-CoV-2 infection and other diseases associated to hypoxia, as they are by themselves chronic inflammatory conditions that may potentially disturb metabolic homeostasis and thereby negatively impact on COVID-19 progression. To unveil the metabolic abnormalities inherent to hypoxemia caused by COVID-19, we here applied gas chromatography coupled to mass spectrometry to analyze the main metabolic changes exhibited by a population of male patients less than 50 years of age with mild/moderate and severe COVID-19 without pre-existing comorbidities known to predispose to life-threatening complications from this infection. Several differences in serum levels of particular metabolites between normal controls and patients with COVID-19 as well as between mild/moderate and severe COVID-19 were identified. These included increased glutamic acid and reduced glutamine, cystine, threonic acid, and proline levels. In particular, using the entire metabolomic fingerprint obtained, we observed that glutamine/glutamate metabolism was associated with disease severity as patients in the severe COVID-19 group presented the lowest and higher serum levels of these amino acids, respectively. These data highlight the hypoxia-derived metabolic alterations provoked by SARS-CoV-2 infection in the absence of pre-existing co-morbidities as well as the value of amino acid metabolism in determining reactive oxygen species recycling pathways, which when impaired may lead to increased oxidation of proteins and cell damage. They also provide insights on new supportive therapies for COVID-19 and other disorders that involve altered redox homeostasis and lower oxygen levels that may lead to better outcomes of disease severity.

Emerging Role of Nicotinamide Riboside in Health and Diseases

Among all the NAD⁺ precursors, nicotinamide riboside (NR) has gained the most attention as a potent NAD⁺-enhancement agent. This recently discovered vitamin, B3, has demonstrated excellent safety and efficacy profiles and is orally bioavailable in humans. Boosting intracellular NAD⁺ concentrations using NR has been shown to provide protective effects against a broad spectrum of pathological conditions, such as neurodegenerative diseases, diabetes, and hearing loss. In this review, an integrated overview of NR research will be presented. The role NR plays in the NAD⁺ biosynthetic pathway will be introduced, followed by a discussion on the synthesis of NR using chemical and enzymatic approaches. NR’s effects on regulating normal physiology and pathophysiology will also be presented, focusing on the studies published in the last five years.

Gut-brain communication in COVID-19: molecular mechanisms, mediators, biomarkers, and therapeutics

INTRODUCTION

Infection with COVID-19 results in acute respiratory symptoms followed by long COVID multi-organ effects presenting with neurological, cardiovascular, musculoskeletal, and gastrointestinal (GI) manifestations. Temporal relationship between gastrointestinal and neurological symptoms is unclear but warranted for exploring better clinical care for COVID-19 patients.

AREAS COVERED

We critically reviewed the temporal relationship between gut-brain axis after SARS-CoV-2 infection and the molecular mechanisms involved in neuroinvasion following GI infection. Mediators are identified that could serve as biomarkers and therapeutic targets in SARS-CoV-2. We discussed the potential therapeutic approaches to mitigate the effects of GI infection with SARS-CoV-2.

EXPERT OPINION

Altered gut microbiota cause increased expression of various mediators, including zonulin causing disruption of tight junction. This stimulates enteric nervous system and signals to CNS precipitating neurological sequalae. Published reports suggest potential role of cytokines, immune cells, B(0)AT1 (SLC6A19), ACE2, TMRSS2, TMPRSS4, IFN-γ, IL-17A, zonulin, and altered gut microbiome in gut-brain axis and associated neurological sequalae. Targeting these mediators and gut microbiome to improve immunity will be of therapeutic significance. In-depth research and well-designed large-scale population-based clinical trials with multidisciplinary and collaborative approaches are warranted. Investigating the temporal relationship between organs involved in long-term sequalae is critical due to evolving variants of SARS-CoV-2.

Integration of protein context improves protein-based COVID-19 patient stratification

BACKGROUND

Classification of disease severity is crucial for the management of COVID-19. Several studies have shown that individual proteins can be used to classify the severity of COVID-19. Here, we aimed to investigate whether integrating four types of protein context data, namely, protein complexes, stoichiometric ratios, pathways and network degrees will improve the severity classification of COVID-19.

METHODS

We performed machine learning based on three previously published datasets. The first was a SWATH (sequential window acquisition of all theoretical fragment ion spectra) MS (mass spectrometry) based proteomic dataset. The second was a TMTpro 16plex labeled shotgun proteomics dataset. The third was a SWATH dataset of an independent patient cohort.

RESULTS

Besides twelve proteins, machine learning also prioritized two complexes, one stoichiometric ratio, five pathways, and five network degrees, resulting a 25-feature panel. As a result, a model based on the 25 features led to effective classification of severe cases with an AUC of 0.965, outperforming the models with proteins only. Complement component C9, transthyretin (TTR) and TTR-RBP (transthyretin-retinol binding protein) complex, the stoichiometric ratio of SAA2 (serum amyloid A proteins 2)/YLPM1 (YLP Motif Containing 1), and the network degree of SIRT7 (Sirtuin 7) and A2M (alpha-2-macroglobulin) were highlighted as potential markers by this classifier. This classifier was further validated with a TMT-based proteomic data set from the same cohort (test dataset 1) and an independent SWATH-based proteomic data set from Germany (test dataset 2), reaching an AUC of 0.900 and 0.908, respectively. Machine learning models integrating protein context information achieved higher AUCs than models with only one feature type.

CONCLUSION

Our results show that the integration of protein context including protein complexes, stoichiometric ratios, pathways, network degrees, and proteins improves phenotype prediction.

N-Acetylcysteine and Other Sulfur-Donors as a Preventative and Adjunct Therapy for COVID-19

The airway epithelial glycocalyx plays an important role in preventing severe acute respiratory syndrome coronavirus 2 entry into the epithelial cells, while the endothelial glycocalyx contributes to vascular permeability and tone, as well as modulating immune, inflammatory, and coagulation responses. With ample evidence in the scientific literature that coronavirus disease 2019 (COVID-19) is related to epithelial and endothelial dysfunction, preserving the glycocalyx should be the main focus of any COVID-19 treatment protocol. The most studied functional unit of the glycocalyx is the glycosaminoglycan heparan sulfate, where the degree and position of the sulfate groups determine the biological activity. N-acetylcysteine (NAC) and other sulfur donors contribute to the inorganic sulfate pool, the rate-limiting molecule in sulfation. NAC is not only a precursor to glutathione but also converts to hydrogen sulfide, inorganic sulfate, taurine, Coenzyme A, and albumin. By optimising inorganic sulfate availability, and therefore sulfation, it is proposed that COVID-19 can be prevented or at least most of the symptoms attenuated. A comprehensive COVID-19 treatment protocol is needed to preserve the glycocalyx in both the prevention and treatment of COVID-19. The use of NAC at a dosage of 600 mg bid for the prevention of COVID-19 is proposed, but a higher dosage of NAC (1200 mg bid) should be administered upon the first onset of symptoms. In the severe to critically ill, it is advised that IV NAC should be administered immediately upon hospital admission, and in the late stage of the disease, IV sodium thiosulfate should be considered. Doxycycline as a protease inhibitor will prevent shedding and further degradation of the glycocalyx.

Differences in Extracellular NAD+ and NMN Metabolism on the Surface of Vascular Endothelial Cells

Simple Summary

Nicotinamide adenine dinucleotide (NAD⁺) is a multifunctional metabolite involved in many key cellular processes. Outside the cell, NAD⁺ or its metabolites are important signaling molecules, related especially to calcium homeostasis, which controls the functioning of the heart. The cleavage of NAD⁺ or its precursor, nicotinamide mononucleotide (NMN), produces derivatives entering the cell to rebuild the intracellular NAD⁺ pool, which is important for cells with high energy turnover. Abnormalities in NAD⁺ and NMN metabolism can lead to cell aging and the development of cardiovascular diseases. In this study, we demonstrated that the extracellular metabolism of NAD⁺ and NMN is vastly different in the vascular endothelium obtained from different species and locations. This may have implications for strategies to modulate the NAD⁺ system and may cause difficulties for comparing the results of different reports.

Abstract

The disruption of the metabolism of extracellular NAD⁺ and NMN may affect related signaling cascades and pathologies, such as cardiovascular or respiratory system diseases. We aimed to study NAD⁺ and NMN hydrolysis on surface endothelial cells of diverse origins and with genetically modified nucleotide catabolism pathways. We tested lung endothelial cells isolated from C57BL/6 J wild-type (WT) and C57BL/6 J CD73 knockout (CD73 KO) mice, the transfected porcine iliac artery endothelial cell line (PIEC) with the human E5NT gene for CD73 (PIEC CD73), and a mock-transfected control (PIEC MOCK), as well as HMEC-1 and H5V cells. Substrate conversion into the product was followed by high-performance liquid chromatography (HPLC). We showed profound differences in extracellular NAD⁺ and NMN metabolism related to the vessel origin, species diversity, and type of culture. We also confirmed the involvement of CD38 and CD73 in NAD⁺ and NMN cleavage.

Oral Administration of Nicotinamide Mononucleotide Is Safe and Efficiently Increases Blood Nicotinamide Adenine Dinucleotide Levels in Healthy Subjects

Nicotinamide mononucleotide (NNM) is an orally bioavailable NAD+ precursor that has demonstrated beneficial effects against aging and aging-associated diseases in animal models. NMN is ultimately converted to NAD+, a redox cofactor that mediates many metabolic enzymes. NAD+ also serves as the substrate for poly(ADP-ribose) polymerase (PARP) and sirtuins, and regulates various biological processes, such as metabolism, DNA repair, gene expression, and stress responses. Previous mouse models showed that NMN administration can increase NAD+ in various organs and ameliorate aging-related diseases, such as obesity, diabetes, heart failure, stroke, kidney failure, and Alzheimer's disease through NAD+-mediated pathways. However, evidence of its effect on humans is still scarce. In this study, we conducted a placebo-controlled, randomized, double blind, parallel-group trial to investigate the safety of orally administered NMN and its efficacy to increase NAD+ levels in thirty healthy subjects. Healthy volunteers received 250 mg/day of NMN (n = 15) or placebo (n = 15) for 12 weeks, and physiological and laboratory tests were performed during this period. In addition, NAD+ and its related metabolites in whole blood were examined. Oral supplementation of NMN for 12 weeks caused no abnormalities in physiological and laboratory tests, and no obvious adverse effects were observed. NAD+ levels in whole blood were significantly increased after NMN administration. We also observed the significant rise in nicotinic acid mononucleotide (NAMN) levels, but not in NMN. We also found that the increased amount of NAD+ was strongly correlated with pulse rate before the administration of NMN. These results suggest that oral administration of NMN is a safe and practical strategy to boost NAD+ levels in humans. Clinical Trial Registration: JRCT [https://jrct.niph.go.jp/], identifier: [jRCTs041200034].

A global picture: therapeutic perspectives for COVID-19

The COVID-19 pandemic is a lethal virus outbreak by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which has severely affected human lives and the global economy. The most vital part of the research and development of therapeutic agents is to design drug products to manage COVID-19 efficiently. Numerous attempts have been in place to determine the optimal drug dose and combination of drugs to treat the disease on a global scale. This article documents the information available on SARS-CoV-2 and its life cycle, which will aid in the development of the potential treatment options. A consolidated summary of several natural and repurposed drugs to manage COVID-19 is depicted with summary of current vaccine development. People with high age, comorbity and concomitant illnesses such as overweight, metabolic disorders, pulmonary disease, coronary heart disease, renal failure, fatty liver and neoplastic disorders are more prone to create serious COVID-19 and its consequences. This article also presents an overview of post-COVID-19 complications in patients.

A global picture: therapeutic perspectives for COVID-19

The COVID-19 pandemic is a lethal virus outbreak by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which has severely affected human lives and the global economy. The most vital part of the research and development of therapeutic agents is to design drug products to manage COVID-19 efficiently. Numerous attempts have been in place to determine the optimal drug dose and combination of drugs to treat the disease on a global scale. This article documents the information available on SARS-CoV-2 and its life cycle, which will aid in the development of the potential treatment options. A consolidated summary of several natural and repurposed drugs to manage COVID-19 is depicted with summary of current vaccine development. People with high age, comorbity and concomitant illnesses such as overweight, metabolic disorders, pulmonary disease, coronary heart disease, renal failure, fatty liver and neoplastic disorders are more prone to create serious COVID-19 and its consequences. This article also presents an overview of post-COVID-19 complications in patients.

Pleiotropic effects of mitochondria in aging

Aging is typified by a progressive decline in mitochondrial activity and stress resilience. Here, we review how mitochondrial stress pathways have pleiotropic effects on cellular and systemic homeostasis, which can comprise protective or detrimental responses during aging. We describe recent evidence arguing that defects in these conserved adaptive pathways contribute to aging and age-related diseases. Signaling pathways regulating the mitochondrial unfolded protein response, mitochondrial membrane dynamics, and mitophagy are discussed, emphasizing how their failure contributes to heteroplasmy and de-regulation of key metabolites. Our current understanding of how these processes are controlled and interconnected explains how mitochondria can widely impact fundamental aspects of aging.

The CD38 glycohydrolase and the NAD sink: implications for pathological conditions

Nicotinamide adenine dinucleotide (NAD) acts as a cofactor in several oxidation-reduction (redox) reactions and is a substrate for a number of nonredox enzymes. NAD is fundamental to a variety of cellular processes including energy metabolism, cell signaling, and epigenetics. NAD homeostasis appears to be of paramount importance to health span and longevity, and its dysregulation is associated with multiple diseases. NAD metabolism is dynamic and maintained by synthesis and degradation. The enzyme CD38, one of the main NAD-consuming enzymes, is a key component of NAD homeostasis. The majority of CD38 is localized in the plasma membrane with its catalytic domain facing the extracellular environment, likely for the purpose of controlling systemic levels of NAD. Several cell types express CD38, but its expression predominates on endothelial cells and immune cells capable of infiltrating organs and tissues. Here we review potential roles of CD38 in health and disease and postulate ways in which CD38 dysregulation causes changes in NAD homeostasis and contributes to the pathophysiology of multiple conditions. Indeed, in animal models the development of infectious diseases, autoimmune disorders, fibrosis, metabolic diseases, and age-associated diseases including cancer, heart disease, and neurodegeneration are associated with altered CD38 enzymatic activity. Many of these conditions are modified in CD38-deficient mice or by blocking CD38 NADase activity. In diseases in which CD38 appears to play a role, CD38-dependent NAD decline is often a common denominator of pathophysiology. Thus, understanding dysregulation of NAD homeostasis by CD38 may open new avenues for the treatment of human diseases.

Effects of L-carnitine supplementation in patients with mild-to-moderate COVID-19 disease: a pilot study

BACKGROUND

The present single-center clinical trial was designed to evaluate the potential benefits of L-carnitine supplementation in patients with COVID-19 disease.

METHODS AND PATIENTS

The study was conducted on 75 patients with mild-to-moderate COVID-19 hospitalized in Shahid Beheshti Hospital-Hamadan, IRAN. The participants were randomly divided into intervention (n = 32) and control groups (n = 43). The control group received their standard hospital treatment only. In addition to standard medications, the intervention group received 3000 mg oral L-carnitine daily in three divided doses for five days. The blood samples were collected and para-clinical parameters were measured at the beginning and end of the treatment. Clinical outcomes were also recorded, and data were analyzed using χ² and t-tests.

RESULTS

Higher means of O2 saturation were observed in the intervention rather than in the control group. Mean erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were significantly lower in the intervention group. Furthermore, mean alkaline phosphatase (ALP) activity and lactate dehydrogenase (LDH) were lower in the intervention group. Also, lower mean serum creatine phosphokinase (CPK) was observed in the intervention group. No significant differences were observed in terms of clinical symptoms; however, six patients (14%) in the control group died due to the complications of COVID-19, while all patients in the intervention group survived.

CONCLUSION

Taken together, L-carnitine can be considered as a drug supplement in patients with COVID-19.

Rationale for Nicotinamide Adenine Dinucleotide (NAD+) Metabolome Disruption as a Pathogenic Mechanism of Post-Acute COVID-19 Syndrome

Many acute COVID-19 convalescents experience a persistent sequelae of infection, called post-acute COVID-19 syndrome (PACS). With incidence ranging between 31% and 69%, PACS is becoming increasingly acknowledged as a new disease state in the context of SARS-CoV-2 infection. As SARS-CoV-2 infection can affect several organ systems to varying degrees and durations, the cellular and molecular abnormalities contributing to PACS pathogenesis remain unclear. Despite our limited understanding of how SARS-CoV-2 infection promotes this persistent disease state, mitochondrial dysfunction has been increasingly recognized as a contributing factor to acute SARS-CoV-2 infection and, more recently, to PACS pathogenesis. The biological mechanisms contributing to this phenomena have not been well established in previous literature; however, in this review, we summarize the evidence that NAD+ metabolome disruption and subsequent mitochondrial dysfunction following SARS-CoV-2 genome integration may contribute to PACS biological pathogenesis. We also briefly examine the coordinated and complex relationship between increased oxidative stress, inflammation, and mitochondrial dysfunction and speculate as to how SARS-CoV-2-mediated NAD+ depletion may be causing these abnormalities in PACS. As such, we present evidence supporting the therapeutic potential of intravenous administration of NAD+ as a novel treatment intervention for PACS symptom management.

Comorbidity-associated glutamine deficiency is a predisposition to severe COVID-19

SARS-CoV-2 vaccinations have greatly reduced COVID-19 cases, but we must continue to develop our understanding of the nature of the disease and its effects on human immunity. Previously, we suggested that a dysregulated STAT3 pathway following SARS-Co-2 infection ultimately leads to PAI-1 activation and cascades of pathologies. The major COVID-19-associated metabolic risks (old age, hypertension, cardiovascular diseases, diabetes, and obesity) share high PAI-1 levels and could predispose certain groups to severe COVID-19 complications. In this review article, we describe the common metabolic profile that is shared between all of these high-risk groups and COVID-19. This profile not only involves high levels of PAI-1 and STAT3 as previously described, but also includes low levels of glutamine and NAD+, coupled with overproduction of hyaluronan (HA). SARS-CoV-2 infection exacerbates this metabolic imbalance and predisposes these patients to the severe pathophysiologies of COVID-19, including the involvement of NETs (neutrophil extracellular traps) and HA overproduction in the lung. While hyperinflammation due to proinflammatory cytokine overproduction has been frequently documented, it is recently recognized that the immune response is markedly suppressed in some cases by the expansion and activity of MDSCs (myeloid-derived suppressor cells) and FoxP3+ Tregs (regulatory T cells). The metabolomics profiles of severe COVID-19 patients and patients with advanced cancer are similar, and in high-risk patients, SARS-CoV-2 infection leads to aberrant STAT3 activation, which promotes a cancer-like metabolism. We propose that glutamine deficiency and overproduced HA is the central metabolic characteristic of COVID-19 and its high-risk groups. We suggest the usage of glutamine supplementation and the repurposing of cancer drugs to prevent the development of severe COVID-19 pneumonia.