Science of NAD
How are your NAD levels today?
NAD deficits seem to be implicated in a number of neurodegenerative disorders, including Alzheimer's Disease. Indeed, NAD replenishment seems to positively impact the pathological hallmarks of the disease, such as cognitive function.
Here are the studies:
Aug 30, 2023
Brain - Alzheimer's - Gut Microbiome
Biochemical and Biophysical Research Communications
Nicotinamide mononucleotide improves the Alzheimer's disease by regulating intestinal microbiota
Zhao, Xiaodong
Jun 23, 2023
Neurons - Neurodegneration - Alzheimer's
Nutrients
Effect of Exercise and Oral Niacinamide Mononucleotide on Improving Mitochondrial Autophagy in Alzheimer’s Disease
Wu, Weijia
SUMMARY
This review summarizes recent studies on the effect of oral NMN on the enhancement of NAD+ in vivo and the improvements in mitochondrial autophagy abnormalities in AD through aerobic exercise, focusing on (1) how oral NMN improves the internal NAD+ level; (2) how exercise regulates the content of NAD+ in the body; (3) the relationship between exercise activation of NAD+ and AMPK; (4) how SIRT1 is regulated by NAD+ and AMPK and activates PGC-1α to mediate mitochondrial autophagy through changes in mitochondrial dynamics. By summarizing the results of the above four aspects, and combined with the synthesis of NAD+ in vivo, we can infer how exercise elevates the level of NAD+ in vivo to mediate mitochondrial autophagy, so as to propose a new hypothesis that exercise interferes with Alzheimer’s disease (AD).
Jan 26, 2023
Brain - Alzheimer's Disease
Translational Neurodegeneration
Combined Metabolic Activators Improves Cognitive Functions in Alzheimer’s Disease
Yulug, Burak
SUMMARY
We designed a randomized, double-blinded, placebo-controlled human phase 2 clinical trial and showed that the administration of CMAs improves cognitive functions in AD patients...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. 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.
Jan 13, 2023
Neurons - Neurodegeneration - Parkinsons - Alzheimer's - Huntington's Disease - ALS
International Journal of Molecular Sciences
A Promising Strategy to Treat Neurodegenerative Diseases by SIRT3 Activation
Tyagi, Alpna
Dec 26, 2022
Neurons - Neurodegeneration - Alzheimer's Disease - Parkinson's Disease
Life Sciences
Combined metabolic activators improve metabolic functions in the animal models of neurodegenerative diseases
Turkez, Hasan
SUMMARY
We showed that combined metabolic activators [including nicotinamide riboside] administration significantly improved behavioural scores in parallel with the neurohistological outcomes in the Alzheimer's Disease and Parkinson's Disease animal models and is a promising treatment for improving the metabolic parameters and brain functions in neurodegenerative diseases.
Dec 14, 2022
Brain - Neurons - Neurodegeneration - Inflammation - Alzheimer's
Aging Cell
Oral nicotinamide riboside raises NAD+ and lowers biomarkers of neurodegenerative pathology in plasma extracellular vesicles enriched for neuronal origin
Vreones, Michael
SUMMARY
We report the first study examining [extracellular vesicles enriched for neuronal origin or "NEV"] NEV biomarkers in response to oral NR supplementation. Our primary analysis of NAD+ and NADH in NEVs suggests an increase in neuronal NAD+ concentration in response to oral NR supplementation....We demonstrate that oral NR supplementation [in humans] increases NAD+ levels in NEVs ...These findings support the ability of orally administered NR to augment neuronal NAD+ levels and modify biomarkers related to neurodegenerative pathology in humans.
Nov 17, 2022
Brain - Alzheimer's - Neuroinflammation - Metabolism - Diabetes
Scientific Reports
Sirt3 deficiency induced down regulation of insulin degrading enzyme in comorbid Alzheimer’s disease with metabolic syndrome
Tyagi, Alpna
SUMMARY
Mitochondrial dysfunction, insulin resistance, metabolic dysregulation and neuroinflammation that contribute to cognitive decline in Alzheimer's Disease...The findings of this study suggest that SIRT3 is a potential therapeutic target for the treatment of AD. Sirtuins, including SIRT3, require NAD+ as a cosubstrate. Administration of NR, a precursor of NAD+, leads to increase in the cellular level of NAD+. In this study, we demonstrate that NR increases the levels of IDE as well as neprilysin and decreases the levels of BACE1 in vivo. Interestingly, NR also increases the levels of SIRT3, probably by autoregulation. NR has been reported to reverse insulin resistance and glucose intolerance in a mouse model for type 2 diabetes. NR has been shown to be effective in reducing neuroinflammation and improve cognition in Alzheimer’s mouse models. Therefore, NR-based treatment can be considered for the treatment of AD with comorbidities.
Nov 10, 2021
Brain - Alzheimer's Disease
Cell & Bioscience
Down-regulation of EPB41L4A-AS1 mediated the brain aging and neurodegenerative diseases via damaging synthesis of NAD + and ATP
Yang, Tingpeng
SUMMARY
...Downregulation of EPB41L4A-AS1 not only disturbs NAD+ biosynthesis but also affects ATP synthesis. As a result, the high demand for NAD+ and ATP in the brain cannot be met, promoting the development of brain aging and neurodegenerative diseases. However, overexpression of EPB41L4A-AS1 and nicotinamide riboside, a substrate of NAD+ synthesis, can reduce EPB41L4A-AS1 downregulation-mediated decrease of NAD+ and ATP synthesis. Our results provide new perspectives on the mechanisms underlying brain aging and neurodegenerative diseases.
Sep 14, 2021
Brain - Alzheimer's Disease
Proceedings of the National Academy of Science
NAD+ supplementation reduces neuroinflammation and cell senescence in a transgenic mouse model of Alzheimer’s disease via cGAS-STING
Hou, Yujun
SUMMARY
...Impaired neuronal bioenergetics and neuroinflammation are thought to play key roles in the progression of Alzheimer's Disease (AD), but their interplay is not clear. Nicotinamide adenine dinucleotide (NAD+) is an important metabolite in all human cells in which it is pivotal for multiple processes including DNA repair and mitophagy, both of which are impaired in AD neurons...Treatment of APP/PS1 mutant mice with the NAD+ precursor nicotinamide riboside (NR) for 5 mo increased brain NAD+ levels, reduced expression of proinflammatory cytokines, and decreased activation of microglia and astrocytes. NR treatment also reduced NLRP3 inflammasome expression, DNA damage, apoptosis, and cellular senescence in the AD mouse brains. Activation of cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING) are associated with DNA damage and senescence. cGAS–STING elevation was observed in the AD mice and normalized by NR treatment...NR treatment induced mitophagy and improved cognitive and synaptic functions in APP/PS1 mutant mice. Our findings suggest a role for NAD+ depletion-mediated activation of cGAS–STING in neuroinflammation and cellular senescence in AD.
Aug 3, 2021
Brain - Alzheimer's Disease
Frontiers in Cell and Developmental Biology
NAD+ in Alzheimer’s Disease: Molecular Mechanisms and Systematic Therapeutic Evidence Obtained in vivo
Wang, Xinshi
SUMMARY
Mitochondria in neurons generate adenosine triphosphate (ATP) to provide the necessary energy required for constant activity. Nicotinamide adenine dinucleotide (NAD+) is a vital intermediate metabolite involved in cellular bioenergetics, ATP production, mitochondrial homeostasis, and adaptive stress responses. Exploration of the biological functions of NAD+ has been gaining momentum, providing many crucial insights into the pathophysiology of age-associated functional decline and diseases, such as Alzheimer’s disease (AD). Here, we systematically review the key roles of NAD+ precursors and related metabolites in AD models and show how NAD+ affects the pathological hallmarks of AD and the potential mechanisms of action. Advances in understanding the molecular roles of NAD+-based neuronal resilience will result in novel approaches for the treatment of AD and set the stage for determining whether the results of exciting preclinical trials can be translated into the clinic to improve AD patients’ phenotypes.
Oct 15, 2020
Brain - Neurons - Alzheimer's Disease
Frontiers in Aging Neuroscience
Axonal Degeneration in AD: The Contribution of Aβ and Tau
Salvadores, Natalia
Sep 1, 2020
Brain - Alzheimer's Disease - Gut Microbiota
Frontiers in Aging Neuroscience
Nicotinamide adenine dinucleotide supplementation drives gut microbiota variation in Alzheimer’s mouse model
Chu, Xixia
SUMMARY
Alzheimer’s disease (AD) is the most common neurodegenerative disease. Growing evidence suggests an important role for gut dysbiosis and gut microbiota-host interactions in aging and neurodegeneration. Our previous works have demonstrated that supplementation with the nicotinamide adenine dinucleotide (NAD+) precursor, nicotinamide riboside (NR), reduced the brain features of AD, including neuroinflammation, deoxyribonucleic acid (DNA) damage, synaptic dysfunction, and cognitive impairment. However, the impact of NR administration on the intestinal microbiota of AD remains unknown. In this study, we investigated the relationship between gut microbiota and NR treatment in APP/PS1 transgenic (AD) mice. Compared with wild type (WT) mice, the gut microbiota diversity in AD mice was lower and the microbiota composition and enterotype were significantly different. Moreover, there were gender differences in gut microbiome between female and male AD mice. After supplementation with NR for 8 weeks, the decreased diversity and perturbated microbial compositions were normalized in AD mice. This included the species Oscillospira, Butyricicoccus, Desulfovibrio, Bifidobacterium, Olsenella, Adlercreutzia, Bacteroides, Akkermansia, and Lactobacillus. Our results indicate an interplay between NR and host-microbiota in APP/PS1 mice, suggesting that the effect of NR on gut dysbiosis may be an important component in its therapeutic functions in AD.
Oct 1, 2019
Brain - Aging - Neurons - Alzheimer's - Parkinson's - Huntington's - ALS
Cell Metabolism
NAD+ in Brain Aging and Neurodegenerative Disorders
Lautrup, Sofie
SUMMARY
NAD+ is a pivotal metabolite involved in cellular bioenergetics, genomic stability, mitochondrial homeostasis, adaptive stress responses, and cell survival. Multiple NAD+-dependent enzymes are involved in synaptic plasticity and neuronal stress resistance. Here, we review emerging findings that reveal key roles for NAD+ and related metabolites in the adaptation of neurons to a wide range of physiological stressors and in counteracting processes in neurodegenerative diseases, such as those occurring in Alzheimer’s, Parkinson’s, and Huntington diseases, and amyotrophic lateral sclerosis. Advances in understanding the molecular and cellular mechanisms of NAD+-based neuronal resilience will lead to novel approaches for facilitating healthy brain aging and for the treatment of a range of neurological disorders.
Feb 5, 2018
Brain - Alzheimer's Disease
Proceedings of the National Academy of Science
NAD+ supplementation normalizes key Alzheimer's features and DNA damage responses in a new AD mouse model with introduced DNA repair deficiency
Hou, Yujun
SUMMARY
Emerging findings suggest that compromised cellular bioenergetics and DNA repair contribute to the pathogenesis of Alzheimer's disease (AD), but their role in disease-defining pathology is unclear. We developed a DNA repair-deficient 3xTgAD/Polβ+/- mouse that exacerbates major features of human AD including phosphorylated Tau (pTau) pathologies, synaptic dysfunction, neuronal death, and cognitive impairment. Here we report that 3xTgAD/Polβ+/- mice have a reduced cerebral NAD+/NADH ratio indicating impaired cerebral energy metabolism, which is normalized by nicotinamide riboside (NR) treatment. NR lessened pTau pathology in both 3xTgAD and 3xTgAD/Polβ+/- mice but had no impact on amyloid β peptide (Aβ) accumulation. NR-treated 3xTgAD/Polβ+/- mice exhibited reduced DNA damage, neuroinflammation, and apoptosis of hippocampal neurons and increased activity of SIRT3 in the brain. NR improved cognitive function in multiple behavioral tests and restored hippocampal synaptic plasticity in 3xTgAD mice and 3xTgAD/Polβ+/- mice. In general, the deficits between genotypes and the benefits of NR were greater in 3xTgAD/Polβ+/- mice than in 3xTgAD mice. Our findings suggest a pivotal role for cellular NAD+ depletion upstream of neuroinflammation, pTau, DNA damage, synaptic dysfunction, and neuronal degeneration in AD. Interventions that bolster neuronal NAD+ levels therefore have therapeutic potential for AD.
Dec 14, 2017
Brain - Alzheimer's Disease
Nature
Enhancing mitochondrial proteostasis reduces amyloid-β proteotoxicity
Sorrentino, Vincenzo
SUMMARY
Alzheimer's disease is a common and devastating disease characterized by aggregation of the amyloid-β peptide. However, we know relatively little about the underlying molecular mechanisms or how to treat patients with Alzheimer's disease. Here we provide bioinformatic and experimental evidence of a conserved mitochondrial stress response signature present in diseases involving amyloid-β proteotoxicity in human, mouse and Caenorhabditis elegans that involves the mitochondrial unfolded protein response and mitophagy pathways. Using a worm model of amyloid-β proteotoxicity, GMC101, we recapitulated mitochondrial features and confirmed that the induction of this mitochondrial stress response was essential for the maintenance of mitochondrial proteostasis and health. Notably, increasing mitochondrial proteostasis by pharmacologically and genetically targeting mitochondrial translation and mitophagy increases the fitness and lifespan of GMC101 worms and reduces amyloid aggregation in cells, worms and in transgenic mouse models of Alzheimer's disease. Our data support the relevance of enhancing mitochondrial proteostasis to delay amyloid-β proteotoxic diseases, such as Alzheimer's disease.
Jun 1, 2013
Brain - Alzheimer's Disease
Neurobiology of Aging
Nicotinamide riboside restores cognition through an upregulation of proliferator-activated receptor-γ coactivator 1α regulated β-secretase 1 degradation and mitochondrial gene expression in Alzheimer's mouse models
Gong, Bing