Nicotinamide Riboside and Dihydronicotinic Acid Riboside Synergistically Increase Intracellular NAD+ by Generating Dihydronicotinamide Riboside

Through evolution, eukaryote organisms have developed the ability to use different molecules as independent precursors to generate nicotinamide adenine dinucleotide (NAD⁺), an essential molecule for life. However, whether these different precursors act in an additive or complementary manner is not truly well understood. Here, we have evaluated how combinations of different NAD⁺ precursors influence intracellular NAD⁺ levels. We identified dihydronicotinic acid riboside (NARH) as a new NAD⁺ precursor in hepatic cells. Second, we demonstrate how NARH, but not any other NAD⁺ precursor, can act synergistically with nicotinamide riboside (NR) to increase NAD⁺ levels in cultured cells and in mice. Finally, we demonstrate that the large increase in NAD⁺ prompted by the combination of these two precursors is due to their chemical interaction and conversion to dihydronicotinamide riboside (NRH). Altogether, this work demonstrates for the first time that NARH can act as a NAD⁺ precursor in mammalian cells and how different NAD⁺ precursors can interact and influence each other when co-administered.     

Supplementation with NAD+ and Its Precursors to Prevent Cognitive Decline across Disease Contexts

The preservation of cognitive ability by increasing nicotinamide adenine dinucleotide (NAD⁺) levels through supplementation with NAD⁺ precursors has been identified as a promising treatment strategy for a number of conditions; principally, age-related cognitive decline (including Alzheimer’s disease and vascular dementia), but also diabetes, stroke, and traumatic brain injury. Candidate factors have included NAD⁺ itself, its reduced form NADH, nicotinamide (NAM), nicotinamide mononucleotide (NMN), nicotinamide riboside (NR), and niacin (or nicotinic acid). This review summarises the research findings for each source of cognitive impairment for which NAD⁺ precursor supplementation has been investigated as a therapy. The findings are mostly positive but have been made primarily in animal models, with some reports of null or adverse effects. Given the increasing popularity and availability of these factors as nutritional supplements, further properly controlled clinical research is needed to provide definitive answers regarding this strategy’s likely impact on human cognitive health when used to address different sources of impairment.     

Cross-Sectional Associations between Dietary Daily Nicotinamide Intake and Patient-Reported Outcomes in Colorectal Cancer Survivors, 2 to 10 Years Post-Diagnosis

Supplementation with nicotinamide adenine dinucleotide (NAD⁺) precursors including dietary nicotinamide has been found to boost tissue NAD⁺ levels and ameliorate oxidative stress-induced damage that contributes to aging and aging-related diseases. The association between dietary NAD⁺ precursors and patient-reported health-related outcomes in cancer survivors has not been investigated. This study aimed to determine associations of dietary nicotinamide intake with different patient-reported outcomes in colorectal cancer survivors, 2 to 10 years post-diagnosis. A total of 145 eligible participants were recruited into this cross-sectional study. Dietary nicotinamide intake level was calculated based on data from 7-day food diaries. Fatigue was assessed with the Checklist Individual Strength (CIS), which is a subscale of the cancer-specific European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC), and anxiety and depression were assessed with Hospital Anxiety and Depression Scale (HADS). Oxidative stress marker serum protein carbonyl contents and serum NAD⁺ levels were measured. A hierarchical linear regression model with confounder adjustment was performed to analyze the association of nicotinamide intake, serum protein carbonyl contents, and NAD⁺ levels with patient-reported outcomes. The median values of daily nicotinamide intake for male and female participants were 19.1 and 14.4 mg, respectively. Daily dietary nicotinamide intake was associated with a lower level of fatigue (β: −14.85 (−28.14, −1.56)) and a lower level of anxiety and depression (β: −4.69 (−8.55, −0.83)). Subgroup analyses by sex showed that a beneficial association between nicotinamide intake and patient-reported outcomes was mainly found in men. To conclude, our findings suggested that higher dietary NAD⁺ precursor nicotinamide intake was cross-sectionally associated with less patient-reported outcomes in CRC survivors.     

Nicotinamide and neurocognitive function

Abstract

Nicotinamide, or vitamin B3, is a precursor of nicotinamide adenine dinucleotide (NAD⁺) and is involved in a multitude of intra- and inter-cellular processes, which regulate some of the cell's metabolic, stress, and immune responses to physiological or pathological signals. As a precursor of NAD⁺, which is a key coenzyme in the production of adenosine triphosphate or cellular energy, nicotinamide has been investigated for potential neuroprotective effects in cellular, animal, and human studies.

Objectives

We aimed to summarize the current evidence on the effect of dietary and supplemental nicotinamide on cognitive function.

Methods

A literature review was conducted on the effects of nicotinamide and its derivatives as a preventive and therapeutic agent for disorders of neurocognitive function. Specific conditions examined include age-related cognitive decline, Alzheimer's disease, Parkinson's disease, and ischaemic and traumatic brain injury.

Results

Data from animal and human interventional studies and epidemiological research suggests that nicotinamide may be beneficial in preserving and enhancing neurocognitive function.

Discussion

Nicotinamide is non-toxic, inexpensive and widely available, and interventional studies in humans, using supplemental doses of nicotinamide, are now warranted.     

Age-Dependent Decline of NAD+—Universal Truth or Confounded Consensus?

Nicotinamide adenine dinucleotide (NAD⁺) is an essential molecule involved in various metabolic reactions, acting as an electron donor in the electron transport chain and as a co-factor for NAD⁺-dependent enzymes. In the early 2000s, reports that NAD⁺ declines with aging introduced the notion that NAD⁺ metabolism is globally and progressively impaired with age. Since then, NAD⁺ became an attractive target for potential pharmacological therapies aiming to increase NAD⁺ levels to promote vitality and protect against age-related diseases. This review summarizes and discusses a collection of studies that report the levels of NAD⁺ with aging in different species (i.e., yeast, C. elegans, rat, mouse, monkey, and human), to determine whether the notion that overall NAD⁺ levels decrease with aging stands true. We find that, despite systematic claims of overall changes in NAD⁺ levels with aging, the evidence to support such claims is very limited and often restricted to a single tissue or cell type. This is particularly true in humans, where the development of NAD⁺ levels during aging is still poorly characterized. There is a need for much larger, preferably longitudinal, studies to assess how NAD⁺ levels develop with aging in various tissues. This will strengthen our conclusions on NAD metabolism during aging and should provide a foundation for better pharmacological targeting of relevant tissues.     

Nicotinamide Riboside for the Prevention and Treatment of Doxorubicin Cardiomyopathy. Opportunities and Prospects

Despite the progress in the development of new anticancer strategies, cancer is rapidly spreading around the world and remains one of the most common diseases. For more than 40 years, doxorubicin has been widely used in the treatment of solid and hematological tumors. At the same time, the problem of its cardiotoxicity remains unresolved, despite the high efficiency of this drug. Symptomatic therapy is used as a treatment for side-effects of doxorubicin or pathological conditions that have already appeared in their background. To date, there are no treatment methods for doxorubicin cardiomyopathy as such. A drug such as nicotinamide riboside can play an important role in solving this problem. Nicotinamide riboside is a pyridine nucleoside similar to vitamin B3 that acts as a precursor to NAD⁺. There is no published research on nicotinamide riboside effects on cardiomyopathy, despite the abundance of works devoted to the mechanisms of its effects in various pathologies. The review analyzes information about the effects of nicotinamide riboside on various experimental models of pathologies, its role in the synthesis of NAD⁺, and also considers the possibility and prospects of its use for the prevention of doxorubicin cardiomyopathy.     

Nicotinamide Riboside Supplementation to Suckling Male Mice Improves Lipid and Energy Metabolism in Skeletal Muscle and Liver in Adulthood

Nicotinamide riboside, an NAD⁺ precursor, has been attracting a lot of attention in recent years due to its potential benefits against multiple metabolic complications and age-related disorders related to NAD⁺ decline in tissues. The metabolic programming activity of NR supplementation in early-life stages is much less known. Here, we studied the long-term programming effects of mild NR supplementation during the suckling period on lipid and oxidative metabolism in skeletal muscle and liver tissues using an animal model. Suckling male mice received a daily oral dose of NR or vehicle (water) from day 2 to 20 of age, were weaned at day 21 onto a chow diet, and at day 90 were distributed to either a high-fat diet (HFD) or a normal-fat diet for 10 weeks. Compared to controls, NR-treated mice were protected against HFD-induced triacylglycerol accumulation in skeletal muscle and displayed lower triacylglycerol levels and steatosis degree in the liver and distinct capacities for fat oxidation and decreased lipogenesis in both tissues, paralleling signs of enhanced sirtuin 1 and AMP-dependent protein kinase signaling. These pre-clinical findings suggest that mild NR supplementation in early postnatal life beneficially impacts lipid and energy metabolism in skeletal muscle and liver in adulthood, serving as a potential preventive strategy against obesity-related disorders characterized by ectopic lipid accumulation.     

Potential of Polyphenols to Restore SIRT1 and NAD+ Metabolism in Renal Disease

SIRT1 is an NAD⁺-dependent class III histone deacetylase that is abundantly expressed in the kidney, where it modulates gene expression, apoptosis, energy homeostasis, autophagy, acute stress responses, and mitochondrial biogenesis. Alterations in SIRT1 activity and NAD⁺ metabolism are frequently observed in acute and chronic kidney diseases of diverse origins, including obesity and diabetes. Nevertheless, in vitro and in vivo studies and clinical trials with humans show that the SIRT1-activating compounds derived from natural sources, such as polyphenols found in fruits, vegetables, and plants, including resveratrol, quercetin, and isoflavones, can prevent disease and be part of treatments for a wide variety of diseases. Here, we summarize the roles of SIRT1 and NAD⁺ metabolism in renal pathophysiology and provide an overview of polyphenols that have the potential to restore SIRT1 and NAD⁺ metabolism in renal diseases.     

A Combination of Nicotinamide and D-Ribose (RiaGev) Is Safe and Effective to Increase NAD+ Metabolome in Healthy Middle-Aged Adults: A Randomized,Triple-Blind,Placebo-Controlled,Cross-Over Pilot Clinical Trial

Nicotinamide adenine dinucleotide (NAD⁺) is an essential cofactor required for proper functioning of all cells and its decline is correlated with advancing age and disease. This randomized, triple-blind, placebo-controlled, crossover pilot study assessed the efficacy and safety of a combination of nicotinamide with D-ribose (RiaGev) for NAD metabolome enhancement and related benefits in healthy middle-aged adults. Supplementing with 1520 mg RiaGev twice daily for 7 days significantly increased the NAD⁺ metabolome in blood, especially NADP⁺ by 27% compared to the placebo group (p = 0.033) and over the baseline (p = 0.007). Increases in glutathione and high energy phosphates were also observed in the blood. Seven-day supplementation with RiaGev significantly (p = 0.013) reduced overall blood glucose without significant changes in insulin secretion (p = 0.796), suggesting an improved insulin sensitivity and glucose tolerance. The waking salivary cortisol of the subjects steadily and significantly decreased (p = 0.026) in the RiaGev group in contrast to the placebo. Subjects in the RiaGev group showed less fatigue, improved mental concentration and motivation over the baseline (p = 0.015, 0.018, and 0.012, respectively) as observed through the Checklist Individual Strength (CIS) questionnaire. There were no clinically relevant adverse events, or alterations in hematology, electrolytes, liver, and kidney markers pre- and post-supplementation. RiaGev appears to be safe and efficacious in increasing NAD⁺ metabolome in healthy middle-aged adults, as shown by this study.     

The effect of antioxidant supplementation on fatigue during exercise: potential role for NAD+(H)

This study compared serum pyridine levels (NAD⁺ /NADH) in trained (n = 6) and untrained (n = 7) subjects after continuous progressive exercise at 50%, 70% then 95% of physical work capacity until fatigue (TTF) after consuming a placebo or antioxidant (AO) cocktail (Lactaway^©). An increase of 17% in TTF was observed in AO as compared to placebo (p = 0.032). This was accompanied by a significant increase in serum NAD⁺ levels (p = 0.037) in the AO supplemented group post exercise. The increases in NAD⁺ and improved endurance reflect lower oxidative stress-induced suppression of aerobic respiration.     

Role of CD38 in Adipose Tissue: Tuning Coenzyme Availability?

Nicotinamide adenine dinucleotide (NAD⁺) is a fundamental molecule in the regulation of energy metabolism, representing both a coenzyme and a substrate for different NAD⁺ degrading enzymes. Among these enzymes, CD38 can be seen under two perspectives: as the enzyme synthesizing Ca²⁺-mobilizing second messenger, starting from NAD⁺, and as the major NAD⁺-consumer, to be inhibited to increase NAD⁺ levels. Indeed, the regulation of NAD⁺ availability is a key event during different processes. In this review, we examine the recent studies related to the modulation of CD38 expression and activity, and the consequent changes in NAD(P)(H), in adipose tissue, during inflammation and cold-induced thermogenesis.     

Dietary Cocoa Flavanols Enhance Mitochondrial Function in Skeletal Muscle and Modify Whole-Body Metabolism in Healthy Mice

Mitochondrial dysfunction is widely reported in various diseases and contributes to their pathogenesis. We assessed the effect of cocoa flavanols supplementation on mitochondrial function and whole metabolism, and we explored whether the mitochondrial deacetylase sirtuin-3 (Sirt3) is involved or not. We explored the effects of 15 days of CF supplementation in wild type and Sirt3^-/- mice. Whole-body metabolism was assessed by indirect calorimetry, and an oral glucose tolerance test was performed to assess glucose metabolism. Mitochondrial respiratory function was assessed in permeabilised fibres and the pyridine nucleotides content (NAD⁺ and NADH) were quantified. In the wild type, CF supplementation significantly modified whole-body metabolism by promoting carbohydrate use and improved glucose tolerance. CF supplementation induced a significant increase of mitochondrial mass, while significant qualitative adaptation occurred to maintain H₂O₂ production and cellular oxidative stress. CF supplementation induced a significant increase in NAD⁺ and NADH content. All the effects mentioned above were blunted in Sirt3^-/- mice. Collectively, CF supplementation boosted the NAD metabolism that stimulates sirtuins metabolism and improved mitochondrial function, which likely contributed to the observed whole-body metabolism adaptation, with a greater ability to use carbohydrates, at least partially through Sirt3.     

Anti-glioma effect of intracranial vaccination with tumor cell lysate plus flagellin in mice

The adjuvant effects of flagellin on regulation of immune response have been proved; whether flagellin could assist tumor cell lysate (TCL) to enhance anti-glioma immunity remains to be investigated. This study tests a hypothesis that therapeuticly intracranial administration with flagellin plus TCL enhances the effects of specific immunotherapy on glioma in mice. In this study, GL261 cells were transferred into C57BL/6 mice and the GL261-bearing mice were subcutaneously or intracranially inoculated with flagellin plus TCL, flagellin, TCL or saline. Our results showed that prophylacticly subcutaneous administration with TCL and flagellin could induce potent cytotoxic T lymphocyte (CTL) and prolong the survival of GL261-bearing mice significantly, but therapeuticly subcutaneous administration failed to. However, therapeuticly intracranial administration of TCL plus flagellin could prolong the survival. Moreover, intracranial administration of flagellin could recruit CD4⁺ T cells and CD8⁺ T cells to brain tissues, induce proliferation of natural killer (NK) cells, CD4⁺ T cells and CD8⁺ T cells in peripheral blood mononuclear cells and induce to splenomegaly. The results suggested that flagellin could be acted as an efficient adjuvant for TCL based vaccine.     

A Theacrine-Based Supplement Increases Cellular NAD+ Levels and Affects Biomarkers Related to Sirtuin Activity in C2C12 Muscle Cells In Vitro

There is evidence in rodents to suggest that theacrine-based supplements modulate tissue sirtuin activity as well as other biological processes associated with aging. Herein, we examined if a theacrine-based supplement (termed NAD3) altered sirtuin activity in vitro while also affecting markers of mitochondrial biogenesis. The murine C2C12 myoblast cell line was used for experimentation. Following 7 days of differentiation, myotubes were treated with 0.45 mg/mL of NAD3 (containing ~2 mM theacrine) for 3 and 24 h (n = 6 treatment wells per time point). Relative to control (CTL)-treated cells, NAD3 treatments increased (p < 0.05) Sirt1 mRNA levels at 3 h, as well as global sirtuin activity at 3 and 24 h. Follow-up experiments comparing 24 h NAD3 or CTL treatments indicated that NAD3 increased nicotinamide phosphoribosyltransferase (NAMPT) and SIRT1 protein levels (p < 0.05). Cellular nicotinamide adenine dinucleotide (NAD⁺) levels were also elevated nearly two-fold after 24 h of NAD3 versus CTL treatments (p < 0.001). Markers of mitochondrial biogenesis were minimally affected. Although these data are limited to select biomarkers in vitro, these preliminary findings suggest that a theacrine-based supplement can modulate select biomarkers related to NAD⁺ biogenesis and sirtuin activity. However, these changes did not drive increases in mitochondrial biogenesis. While promising, these data are limited to a rodent cell line and human muscle biopsy studies are needed to validate and elucidate the significance of these findings.     

Temporal Dynamics of T Helper Populations in the Proximal Small Intestine after Oral Bovine Lactoferrin Administration in BALB/c Mice

Bovine lactoferrin (bLf), a component of milk and a dietary supplement, modulates intestinal immunity at effector and inductor sites. Considering the regional difference in intestinal compartments and the dynamics of local cytokine-producing cells in the gut across time, the aim of this work was to characterize the effects of bLf on the proximal small intestine in a BALB/c murine model of oral administration. Male BALB/c mice were treated with oral bLf vs. saline control as mock by buccal deposition for 28 days. Intestinal secretions were obtained at different time points and cells were isolated from Peyer’s patches (PP) and lamina propria (LP) of the proximal small intestine as representative inductor and effector sites, respectively. Total and specific anti-bLF IgA and IgM were determined by enzyme-immuno assay; the percentages of IgA⁺ and IgM⁺ plasma cells (PC) and cytokine-producing CD4⁺ T cells of PP and LP were analyzed by flow cytometry. We found that total and bLf-specific IgA and IgM levels were increased in the intestinal secretions of the bLf group in comparison to mock group and day 0. LP IgA⁺ PC and IgM⁺ PC presented an initial elevation on day 7 and day 21, respectively, followed by a decrease on day 28 in comparison to mock. Higher percentages of CD4⁺ T cells in LP were found in the bLf group. Cytokines-producing CD4⁺ T cells populations presented a pattern of increases and decreases in the bLf group in both LP and PP. Transforming growth factor beta (TGF-β)⁺ CD4⁺ T cells showed higher percentages after bLf administration with a marked peak at day 21 in both LP and PP in comparison to mock-treated mice. Oral bLf exhibits complex immune properties in the proximal small intestine, where temporal monitoring of the inductor and effector compartments reveals patterns of rises and falls of different cell populations. Exceptionally, TGF-β⁺ CD4⁺ T cells show consistent higher numbers after bLf intervention across time. Our work suggests that isolated measurements do not show the complete picture of the modulatory effects of oral bLf in immunological sites as dynamic as the proximal small intestine.     

Lignans are Accessible to Human Breast Cancer Xenografts in Athymic Mice

Lignan-rich diet has been linked with reduced breast cancer risk, and experimental studies have supported the hypothesis of lignans as cancer growth inhibiting compounds. However, it has not been clear if these compounds are accessible in the mammary tumor tissue in vivo. In this study, the accessibility and accumulation of lignans to breast cancer tissue was determined after oral administration of tritium labeled dietary lignan secoisolariciresinol diglucoside ( ³ H-SDG) to athymic mice bearing MCF-7 tumors. The ³ H-SDG administration increased tumor tissue radioactivity to the level similar to that in brain, skin, spleen, kidney, uterus, and lungs. The tumor tissue radioactivity was up to 92% of that found in serum, with the highest concentrations found in small (< 0.5 g) tumors. Accessibility of lignans to tumor tissue suggests that part of the anticancer activity of lignans may be due to their direct local effects on the breast cancer tissues.     

THE EFFECT OF NICOTINIC ACID ON THE DEPRESSANT ACTION OF ETHANOL AND PENTOBARBITAL

The effect of nicotinic acid (NA) on sleeping time induced bya single dose of ethanol or pentobarbital was studied in rats.It was found that sleeping time was markedly reduced by NA ina dose-dependent manner. The effect was observed when NA wasadministered 10 min before or after ethanol or pentobarbital,but not when given 60 min in advance. NA did not affect therate of ethanol elimination measured up to 5 hr after ethanoladministration. Rats pretreated with NA 60 min before ethanolslept longer than controls. This latter effect was not observedwith pentobarbital. These observations, together with the knownlack of effect of high liver NAD⁺ levels on ethanol metabolismand the rather stable NAD⁺ concentration in brain cells, suggestthat the effect of NA on sleeping time is not mediated by anincrease in ethanol metabolism in liver or by NAD⁺ or NAD⁺-dependentreactions in brain. Our results are consistent with a directaction of NA, or some rapidly formed derivative, on a structureor process associated with brain cell functions or membranes.     

Antigenic peptide nanofibers elicit adjuvant-free CD8 T cell responses

Vaccines that elicit robust CD8⁺ T cell responses are desirable for protection against infectious diseases and cancers. However, most vaccine adjuvants fail to elicit robust CD8⁺ T cell responses without inflammation and associated toxicity. We recently reported that self-assembling peptides that form nanofibers in physiological buffers elicited strong adjuvant-free and antigen-specific antibody responses in mice. However, whether or not such nanofibers likewise can elicit strong CD8⁺ T cell responses is unknown. Here, we demonstrate that the self-assembling peptide Q11 conjugated to a CD8⁺ T cell epitope of ovalbumin (Q11-OVA), elicits strong antigen-specific primary and recall responses, and in a vaccination regimen protects against subsequent infection. Importantly, we show that these antigenic peptide nanofibers do not persist as an inflammatory antigen depot at the injection site. Our results demonstrate for the first time that self-assembling peptides may be useful as carriers for vaccines where CD8⁺ T cell-mediated protection is needed.     

Induction of protection in mice against a respiratory challenge by a vaccine formulated with the Chlamydia major outer membrane protein adjuvanted with IC31®

IC31^®, a novel adjuvant, has been shown to be effective by increasing the levels of IFN-γ in animal models when delivered with several antigens. Here, we tested the ability of IC31^®, to enhance the protective ability of the Chlamydia trachomatis native major outer membrane protein (nMOMP). BALB/c mice were immunized by the intramuscular (i.m.) and subcutaneous (s.c.) routes with nMOMP + IC31^®. Another group of animals was immunized with nMOMP + Alum and as a negative control mice were immunized with ovalbumin (Ova) + IC31^®. Animals immunized with nMOMP + IC31^® developed high Chlamydia-specific IgG titers. The serum levels of IgG1 were higher than those of the IgG2a. T cells, from the spleens of mice immunized with IC31^®-adjuvanted nMOMP demonstrated a strong lymphoproliferative reaction to Chlamydia elementary bodies (EB) compared with the groups immunized with nMOMP + Alum or Ova + IC31^®. A similar comparison between these groups of mice revealed that the levels of IFN-γ in the supernatants from stimulated T-cells were significantly higher in animals immunized with nMOMP + IC31^®. Following an intranasal challenge with C. trachomatis, the mice immunized with IC31^®-adjuvanted nMOMP showed significant protection. The change in body weight, an indication of the severity of the infection, was significantly less reduced in mice immunized with nMOMP + IC31^®. Furthermore, the weight of the lungs, as well as the pulmonary Chlamydia burden, was significantly lower in the animals immunized with nMOMP + IC31^® when compared with the groups immunized with nMOMP + Alum or with Ova + IC31^®. In conclusion, these results provide the rationale for further preclinical testing of IC31^® using other chlamydial antigens, and support the potential evaluation of this adjuvant in human vaccines against Chlamydia.