Life Extension Magazine®

Issue: Feb 2019

Ribogen, NAD+, B Vitamins, and Senolytics


Robuvit® (Quercus robur extract) supplementation in subjects with chronic fatigue syndrome and increased oxidative stress. A pilot registry study.

AIM: The aim of this registry study was to evaluate the effects of supplementation with Robuvit® (French Quercus robur extract) capsules in subjects with Chronic Fatigue Syndrome (CFS) associated with an increased oxidative stress. Robuvit is a wood extract from Quercus robur (Horphag Research) used to improve liver dysfunction and chronic fatigue. After excluding any disease, subjects observed a defined management plan to improve CFS. Signs/symptoms had been present for more than 6 months in association with an increase in oxidative stress (measured as plasma free radicals). Blood tests were within normal values. METHODS: The registry study included 38 CFS subjects and 42 comparable controls. There were no dropouts in the 4 weeks of follow-up; the subjects were evaluated for a further period of 6 months. The management plan included: improved/increased sleep; reduction/abolition in smoking and alcohol or any other agent that may have affected them; control of diet, increase in dietary proteins; good hydration; rest (1/2-1 h/day) and exercise (at least 30 min/day); planned relaxation time; increased time in open spaces. In the Robuvit® supplementation group 300 mg/day of Robuvit® was used. RESULTS: Symptoms improved in both groups with a significantly more important improvement in the supplement group (P<0.05). The single items in the Multidimensional Assessment of Fatigue (MAF) questionnaire were statistically better improved (P<0.05) in the supplement group. A parallel improvement in oxidative stress was observed in the supplemented subjects. In the follow up, at 6 months no organic disease was discovered or disease markers found. CONCLUSION: This preliminary registry indicates that supplementation with Robuvit® improves CFS in otherwise healthy subjects with no presence of clinical disease or risk conditions. The effects of Robuvit® in CFS may be partially mediated by a clear reduction of plasma free radicals and oxidative stress.

J Neurosurg Sci. 2015 Jun;59(2):10517.

Robuvit® (French oak wood extract) in the management of functional, temporary hepatic damage. A registry, pilot study.

AIM: The aim of this registry study was to evaluate the evolution of moderate functional hepatic failure (MTHF) using a proprietary new oak wood supplement (Robuvit®) extracted from Quercus Robur. Recent studies have indicated the protective effect of oak wood extracts on liver injury. Quercus wood extracts have shown hepatoprotective effect on initial induced liver-injury. METHODS: This registry included a total of 75 patients with MTHF characterized by: decreased albumin levels; increased total bilirubin, altered hepatic functions enzymes, increased oxidative stress, negative viral hepatitis markers. RESULTS: The two groups (best management in comparison with best management+ Robuvit®) were comparable: 32 Robuvit® patients and 29 comparable controls) completed the 12-week registry. At inclusion, the blood parameter values in the two groups were comparable. At the end of the supplementation period, the increase in albumin levels was significantly (P<0.05 at 12 weeks) faster and higher in the Robuvit® group. The decrease in ALT-SGPT and AST-ASAT was significant in the supplement group (P<0.05 at 4 and 12 weeks); the tests were normalized at 4 and 12 weeks. Controls remained out of the normal range for more than 12 weeks. Alkaline phosphatase was normalized at 4 and 12 weeks in Robuvit® patients; they were decreased, but not normalized in controls at 4 weeks (Robuvit® group’s values were significantly better; P<0.05). Values were normalized in controls (significantly higher in comparison with Robuvit®; P<0.05) at 12 weeks. Total bilirubin was normalized in Robuvit® subjects at 4 and 12 weeks. Results were significantly better in comparison with controls (P<0.05). Direct bilirubin values increased more in the Robuvit® group at 4 and 12 weeks (P<0.05). Gamma GT values were normalized at 4 and 12 weeks in the Robuvit® group. There was a less important decrease in controls (P<0.05) without normalization at 12 weeks. Plasma free radicals increased at inclusion showed a significant decrease in Robuvit® subject (at 4 and 12 weeks) with normalization at 12 weeks. Persisting, elevated values in controls were observed even at 12 weeks (P<0.05). ESR and CRP decreased in both groups with a more important decrease in the Robuvit® group (P<0.05). Hepatitis markers were negative when repeated at 4 and 12 weeks. CONCLUSION: Data from this pilot, supplement registry study indicate a significant protective activity of Robuvit®, associated with a very good safety profile, in patients with temporary hepatic failure. The activity of Robuvit® seems to be mediated by its anti-inflammatory activity.

Minerva Med. 2014 Feb;105(1):41-50.

Improved management of primary chronic fatigue syndrome with the supplement French oak wood extract (Robuvit®): a pilot, registry evaluation.

AIM: The aim of this supplement study was to evaluate French oak wood extract (Robuvit®, Horphag Research Ltd) used as a supplement in association with a defined management plan for chronic fatigue syndrome (CFS) in healthy subjects with CFS, a condition that has, so far, no specific treatment or management standards. METHODS: Robuvit® is a new proprietary and exclusive extract of oak wood with important antoxidant actions. The dosage of the supplementation was 200 mg/day for at least 6 months. The CFS questionnaire and the Brief Mood Introspection Scale (BMIS) questionnaire were used to evaluate mood variations associated with CFS patients. The CFS form includes an analogue scale to record the variations of single symptoms with a score range of 0-10. At inclusion into the registry study, at least 5 symptoms were present. All subjects (age range 35-44; BMI range 24-26) with CFS were tested for oxidative stress: 61 out of 91 subjects had an increased value of oxidative stress. The BMIS scale evaluating mood changes in time was also used. The evaluation was repeated at 3 and 6 months. RESULTS: Out of 91 eligible subjects with CFS, 48 subjects (31 with increased oxidative stress) were accepted as part of the supplement registry study using Robuvit; 43 (30 with increased oxidative stress) were accepted as controls using only the management plan. In the Robuvit® group there were 3 drop outs; also 3 controls were lost. Oxidative stress was increased in 64.58% of subjects that used Robuvit and in 69.7% of controls. The average values of oxidative stress were expressed for the whole group. The average follow up was 199.3;9.2 days in the Robuvit group and 202.2;5.5 in the control group with a minimum of 6 months. Considering variations in oxidative stress, there was no significant average change in controls, but a significant decrease from the initial values was observed in Robuvit subjects after 3 and 6 months. The CFS questionnaire variations in score indicated that there was a significant improvement for most symptoms after 3 and 6 months in the Robuvit group. Positive variations were also present in controls, indicating the positive effect of an increased attention to CFS. The improvement in signs/symptoms was significantly more valuable in subjects using the oak wood extract considering the main 8 symptoms and the accessory symptoms. Considering the BMIS variations, the totals for positive and negative items were significantly more favourable for Robuvit subjects. Overall mood evaluation in the oak wood extract group improved from an inclusion average of -6.93;2.1 to +4.32;2.6 at 6 months; in contrast it changed from -6.5;2.5 to -3.4;1.5 in controls. No side effects were observed during the supplementation with Robuvit. The compliance was optimal with 93% of the capsules correctly used. CONCLUSION: This promising pilot supplement registry study indicates a new opportunity of management for these difficult and often neglected patients. Correlation between oxidative stress and CFS have to be better explored.

Panminerva Med. 2014 Mar;56(1):63-72.

Robuvit®: improvement of fatigue in medical convalescence.

BACKGROUND: The aim of this registry study was the evaluation of symptoms of fatigue following supplementation with an oak wood extract (Robuvit®) after disappearance of acute symptoms. Robuvit®, with established antioxidant-antifatigue activity, has been successfully used in hepatic failure and in chronic fatigue syndrome: these conditions are characterized by weakness and fatigue and are broadly comparable to convalescence that is associated to increased oxidative stress. METHODS: The registry study lasted 3 weeks. After a period (7-10 days) of flu, during the post-disease period (3 days without disease) subjects were included into the study. One group of subjects was supplemented with Robuvit® (300 mg/day) in addition to a standard management (SM) plan, another group of patients was treated with the standard management only. RESULTS: The SM and the supplement group were comparable in all convalescence parameters at inclusion. Weakness and heart rate were significantly reduced with Robuvit® in comparison with the controls (P<0.05) at 10 days and at 3 weeks; Attention and sleep patterns improved significantly at 3 weeks with Robuvit® (P<0.05) in comparison to controls. Recovery after efforts was normalized at 10 days in the supplement group, significantly better versus controls (P<0.05). O2 saturation increased significantly with Robuvit® at 10 days in comparison to controls (P<0.05). The alterations in working/concentration capacity were better improved with the supplement (P<0.05). Oxidative stress was significantly decreased (P<0.05) in comparison to controls. The improvement of health according to the Karrnofsky Scale was significantly more pronounced in the Robuvit® group (P<0.05). The supplement was well tolerated. CONCLUSIONS: The causative relations between Robuvit® supplementation, oxidative stress, vigor and fatigue in convalescence need more specific evaluations in a larger number of subjects. This preliminary study may indicate a possible supplementation in convalescence.

J Sports Med Phys Fitness. 2018 May;58(5): 678-683.

Baloxavir heralds a new era in influenza virus biology.

Baloxavir marboxil is an orally available prodrug of baloxavir acid. Japan was the first country to approve baloxavir marboxil as a treatment for influenza. The antiviral mechanism of action of baloxavir is unique; the drug blocks initiation of viral mRNA synthesis, thus preventing proliferation of the influenza virus. A single oral dose of baloxavir is usually well tolerated; it hastens alleviation of influenza symptoms and shortens the duration of viral shedding. However, novel influenza variants exhibiting over 10-fold reductions in baloxavir susceptibility emerged in baloxavir-treated patients. Although further clinical investigation is required to explore this issue, baloxavir may revolutionize our understanding of influenza virus biology.

Respir Investig. 2018 Nov 2. pii: S2212-5345(18)30189-8.


Nicotinamide Riboside Preserves Cardiac Function in a Mouse Model of Dilated Cardiomyopathy.

BACKGROUND: Myocardial metabolic impairment is a major feature in chronic heart failure. As the major coenzyme in fuel oxidation and oxidative phosphorylation and a substrate for enzymes signaling energy stress and oxidative stress response, nicotinamide adenine dinucleotide (NAD+) is emerging as a metabolic target in a number of diseases including heart failure. Little is known on the mechanisms regulating homeostasis of NAD+ in the failing heart. METHODS: To explore possible alterations of NAD+ homeostasis in the failing heart, we quantified the expression of NAD+ biosynthetic enzymes in the human failing heart and in the heart of a mouse model of dilated cardiomyopathy (DCM) triggered by Serum Response Factor transcription factor depletion in the heart (SRFHKO) or of cardiac hypertrophy triggered by transverse aorta constriction. We studied the impact of NAD+ precursor supplementation on cardiac function in both mouse models. RESULTS: We observed a 30% loss in levels of NAD+ in the murine failing heart of both DCM and transverse aorta constriction mice that was accompanied by a decrease in expression of the nicotinamide phosphoribosyltransferase enzyme that recycles the nicotinamide precursor, whereas the nicotinamide riboside kinase 2 (NMRK2) that phosphorylates the nicotinamide riboside precursor is increased, to a higher level in the DCM (40-fold) than in transverse aorta constriction (4-fold). This shift was also observed in human failing heart biopsies in comparison with nonfailing controls. We show that the Nmrk2 gene is an AMP-activated protein kinase and peroxisome proliferator-activated receptor a responsive gene that is activated by energy stress and NAD+ depletion in isolated rat cardiomyocytes. Nicotinamide riboside efficiently rescues NAD+ synthesis in response to FK866-mediated inhibition of nicotinamide phosphoribosyltransferase and stimulates glycolysis in cardiomyocytes. Accordingly, we show that nicotinamide riboside supplementation in food attenuates the development of heart failure in mice, more robustly in DCM, and partially after transverse aorta constriction, by stabilizing myocardial NAD+ levels in the failing heart. Nicotinamide riboside treatment also robustly increases the myocardial levels of 3 metabolites, nicotinic acid adenine dinucleotide, methylnicotinamide, and N1-methyl-4-pyridone-5-carboxamide, that can be used as validation biomarkers for the treatment. CONCLUSIONS: The data show that nicotinamide riboside, the most energy-efficient among NAD precursors, could be useful for treatment of heart failure, notably in the context of DCM, a disease with few therapeutic options.

Circulation. 2018 May 22;137(21):2256-2273.

Nicotinamide riboside is uniquely and orally bioavailable in mice and humans.

Nicotinamide riboside (NR) is in wide use as an NAD+ precursor vitamin. Here we determine the time and dose-dependent effects of NR on blood NAD+ metabolism in humans. We report that human blood NAD+ can rise as much as 2.7-fold with a single oral dose of NR in a pilot study of one individual, and that oral NR elevates mouse hepatic NAD+ with distinct and superior pharmacokinetics to those of nicotinic acid and nicotinamide. We further show that single doses of 100, 300 and 1,000 mg of NR produce dose-dependent increases in the blood NAD+ metabolome in the first clinical trial of NR pharmacokinetics in humans. We also report that nicotinic acid adenine dinucleotide (NAAD), which was not thought to be en route for the conversion of NR to NAD+, is formed from NR and discover that the rise in NAAD is a highly sensitive biomarker of effective NAD+ repletion.

Nat Commun. 2016 Oct 10;7:12948.

Nicotinamide Riboside Opposes Type 2 Diabetes and Neuropathy in Mice.

Male C57BL/6J mice raised on high fat diet (HFD) become prediabetic and develop insulin resistance and sensory neuropathy. The same mice given low doses of streptozotocin are a model of type 2 diabetes (T2D), developing hyperglycemia, severe insulin resistance and diabetic peripheral neuropathy involving sensory and motor neurons. Because of suggestions that increased NAD(+) metabolism might address glycemic control and be neuroprotective, we treated prediabetic and T2D mice with nicotinamide riboside (NR) added to HFD. NR improved glucose tolerance, reduced weight gain, liver damage and the development of hepatic steatosis in prediabetic mice while protecting against sensory neuropathy. In T2D mice, NR greatly reduced non-fasting and fasting blood glucose, weight gain and hepatic steatosis while protecting against diabetic neuropathy. The neuroprotective effect of NR could not be explained by glycemic control alone. Corneal confocal microscopy was the most sensitive measure of neurodegeneration. This assay allowed detection of the protective effect of NR on small nerve structures in living mice. Quantitative metabolomics established that hepatic NADP(+) and NADPH levels were significantly degraded in prediabetes and T2D but were largely protected when mice were supplemented with NR. The data justify testing of NR in human models of obesity, T2D and associated neuropathies.

Sci Rep. 2016 May 27;6:26933.

Nicotinamide riboside, a form of vitamin B3 and NAD+ precursor, relieves the nociceptive and aversive dimensions of paclitaxel-induced peripheral neuropathy in female rats.

Injury to sensory afferents may contribute to the peripheral neuropathies that develop after administration of chemotherapeutic agents. Manipulations that increase levels of nicotinamide adenine dinucleotide (NAD) can protect against neuronal injury. This study examined whether nicotinamide riboside (NR), a third form of vitamin B3 and precursor of NAD, diminishes tactile hypersensitivity and place escape-avoidance behaviors in a rodent model of paclitaxel-induced peripheral neuropathy. Female Sprague-Dawley rats received 3 intravenous injections of 6.6 mg/kg paclitaxel over 5 days. Daily oral administration of 200 mg/kg NR beginning 7 days before paclitaxel treatment and continuing for another 24 days prevented the development of tactile hypersensitivity and blunted place escape-avoidance behaviors. These effects were sustained after a 2-week washout period. This dose of NR increased blood levels of NAD by 50%, did not interfere with the myelosuppressive effects of paclitaxel, and did not produce adverse locomotor effects. Treatment with 200 mg/kg NR for 3 weeks after paclitaxel reversed the well-established tactile hypersensitivity in a subset of rats and blunted escape-avoidance behaviors. Pretreatment with 100 mg/kg oral acetyl-L-carnitine (ALCAR) did not prevent paclitaxel-induced tactile hypersensitivity or blunt escape-avoidance behaviors. ALCAR by itself produced tactile hypersensitivity. These findings suggest that agents that increase NAD, a critical cofactor for mitochondrial oxidative phosphorylation systems and cellular redox systems involved with fuel utilization and energy metabolism, represent a novel therapeutic approach for relief of chemotherapy-induced peripheral neuropathies. Because NR is a vitamin B3 precursor of NAD and a nutritional supplement, clinical tests of this hypothesis may be accelerated.

Pain. 2017 May;158(5):962-972.

NAD+ supplementation normalizes key Alzheimer’s features and DNA damage responses in a new AD mouse model with introduced DNA repair deficiency.

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/Polb+/- 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/Polb+/- 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/Polb+/- mice but had no impact on amyloid b peptide (Ab) accumulation. NR-treated 3xTgAD/Polb+/- 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/Polb+/- mice. In general, the deficits between genotypes and the benefits of NR were greater in 3xTgAD/Polb+/- 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.

Proc Natl Acad Sci U S A. 2018 Feb 20;115(8):E1876-E1885.

Nicotinamide offers multiple protective mechanisms in stroke as a precursor for NAD+, as a PARP inhibitor and by partial restoration of mitochondrial function.

The purpose of the current study was to investigate aspects of improved bioenergetic function using nicotinamide during stroke. Using a global ischemia-reperfusion mouse model, ATP was depleted by 50% in the brain. The use of nicotinamide to provide a large reserve of brain NAD+ restored ATP levels to 61% of control levels. Alternatively, using nicotinamide as a PARP inhibitor restored ATP levels up to 72%. However, using a large reserve of NAD+ in the brain together with PARP inhibition proved to be additive, restoring ATP to 85% of control levels during the first critical 5 min of reperfusion. NAD+ and ATP levels correlated almost exactly. Brain mitochondrial function was also examined after cerebral ischemia-reperfusion. State 3 respiration of complex I was found to be abolished. However, this was a non-permanent inhibition of activity in vitro, since (NADH ubiquinone oxideroductase) complex I activity in these mitochondria was restored upon the addition of NADH. In vivo, the use of increased brain NAD+ and PARP inhibition was able to partially restore mitochondrial respiration. Taken together, the results show that nicotinamide offers a substantial protective role in terms of preservation of cellular ATP and mitochondrial NAD-linked respiration.

Pharmacology. 2003 Nov;69(3):150-7.

NAMPT-Mediated NAD(+) Biosynthesis Is Essential for Vision In Mice.

Photoreceptor death is the endpoint of many blinding diseases. Identifying unifying pathogenic mechanisms in these diseases may offer global approaches for facilitating photoreceptor survival. We found that rod or cone photoreceptor-specific deletion of nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme in the major NAD(+) biosynthetic pathway beginning with nicotinamide, caused retinal degeneration. In both cases, we could rescue vision with nicotinamide mononucleotide (NMN). Significantly, retinal NAD(+) deficiency was an early feature of multiple mouse models of retinal dysfunction, including light-induced degeneration, streptozotocin-induced diabetic retinopathy, and age-associated dysfunction. Mechanistically, NAD(+) deficiency caused metabolic dysfunction and consequent photoreceptor death. We further demonstrate that the NAD(+)-dependent mitochondrial deacylases SIRT3 and SIRT5 play important roles in retinal homeostasis and that NAD(+) deficiency causes SIRT3 dysfunction. These findings demonstrate that NAD(+) biosynthesis is essential for vision, provide a foundation for future work to further clarify the mechanisms involved, and identify a unifying therapeutic target for diverse blinding diseases.

Cell Rep. 2016 Sep 27;17(1):69-85.

Effect of nicotinamide mononucleotide on brain mitochondrial respiratory deficits in an Alzheimer’s disease-relevant murine model.

BACKGROUND: Mitochondrial dysfunction is a hallmark of neurodegenerative diseases including Alzheimer’s disease (AD), with morphological and functional abnormalities limiting the electron transport chain and ATP production. A contributing factor of mitochondrial abnormalities is loss of nicotinamide adenine dinucleotide (NAD), an important cofactor in multiple metabolic reactions. Depletion of mitochondrial and consequently cellular NAD(H) levels by activated NAD glycohydrolases then culminates in bioenergetic failure and cell death. De Novo NAD(+) synthesis from tryptophan requires a multi-step enzymatic reaction. Thus, an alternative strategy to maintain cellular NAD(+) levels is to administer NAD(+) precursors facilitating generation via a salvage pathway. We administered nicotinamide mononucleotide (NMN), an NAD(+) precursor to APP(swe)/PS1(DE9) double transgenic (AD-Tg) mice to assess amelioration of mitochondrial respiratory deficits. In addition to mitochondrial respiratory function, we examined levels of full-length mutant APP, NAD(+)-dependent substrates (SIRT1 and CD38) in homogenates and fission/fusion proteins (DRP1, OPA1 and MFN2) in mitochondria isolated from brain. To examine changes in mitochondrial morphology, bigenic mice possessing a fluorescent protein targeted to neuronal mitochondria (CaMK2a-mito/eYFP), were administered NMN. METHODS: Mitochondrial oxygen consumption rates were examined in N2A neuroblastoma cells and non-synaptic brain mitochondria isolated from mice (3 months). Western blotting was utilized to assess APP, SIRT1, CD38, DRP1, OPA1 and MFN2 in brain of transgenic and non-transgenic mice (3-12 months). Mitochondrial morphology was assessed with confocal microscopy. One-way or two-way analysis of variance (ANOVA) and post-hoc Holm-Sidak method were used for statistical analyses of data. Student t-test was used for direct comparison of two groups. RESULTS: We now demonstrate that mitochondrial respiratory function was restored in NMN-treated AD-Tg mice. Levels of SIRT1 and CD38 change with age and NMN treatment. Furthermore, we found a shift in dynamics from fission to fusion proteins in the NMN-treated mice. CONCLUSIONS: This is the first study to directly examine amelioration of NAD(+) catabolism and changes in mitochondrial morphological dynamics in brain utilizing the immediate precursor NMN as a potential therapeutic compound. This might lead to well-defined physiologic abnormalities that can serve an important role in the validation of promising agents such as NMN that target NAD(+) catabolism preserving mitochondrial function.

BMC Neurol. 2015 Mar 1;15:19.


Homocysteine and coronary artery disease in French Canadian subjects: relation with vitamins B12, B6, pyridoxal phosphate, and folate.

We determined plasma levels of homocysteine in 584 healthy subjects (380 men and 204 women) from a major utility company in the province of Québec, Canada, and in 150 subjects (123 men and 27 women) with angiographically documented coronary artery disease (CAD) (age < 60 years). Plasma levels of vitamins B12, B6, pyridoxal phosphate (a vitamin B6 derivative), and folate were also determined. Mean homocysteine levels were higher (p < 0.05) in the bottom quartiles for folate, vitamin B12, and pyridoxal phosphate. A significant correlation was noted between homocysteine levels and folate and vitamin B12 levels. No significant correlation was found between plasma homocysteine levels and age, lipids and lipoprotein cholesterol, glucose, and the presence of hypertension or cigarette smoking in healthy subjects or in patients with CAD. Control men had higher homocysteine levels than control women (p < 0.005). Men and women with CAD had higher levels of homocysteine than controls (11.7 +/- 5.8 vs 9.7 +/- 4.9 nmol/ml [p < 0.001] and 12.0 +/- 6.3 vs 7.6 +/- 4.1 nmol/ml, p < 0.01, respectively). Women and men with CAD had similar homocysteine levels. The proportion of patients with CAD having homocysteine levels > 90th percentile of controls was 18.1% for men and 44.4% for women (both p < 0.01). Significantly lower pyridoxal phosphate levels were seen in subjects with CAD, men and women combined (27.7 +/- 29.5 vs 42.1 +/- 38.4 ng/ml, p < 0.005). No significant differences were observed for B12, folate, or total B6.

Am J Cardiol. 1995 Jun 1;75(16):1107-11.

Homocysteine metabolism.

Homocysteine is a sulfur amino acid whose metabolism stands at the intersection of two pathways: remethylation to methionine, which requires folate and vitamin B12 (or betaine in an alternative reaction); and transsulfuration to cystathionine, which requires pyridoxal-5’-phosphate. The two pathways are coordinated by S-adenosylmethionine, which acts as an allosteric inhibitor of the methylenetetrahydrofolate reductase reaction and as an activator of cystathionine beta-synthase. Hyperhomocysteinemia, a condition that recent epidemiological studies have shown to be associated with increased risk of vascular disease, arises from disrupted homocysteine metabolism. Severe hyperhomocysteinemia is due to rare genetic defects resulting in deficiencies in cystathionine beta synthase, methylenetetrahydrofolate reductase, or in enzymes involved in methyl-B12 synthesis and homocysteine methylation. Mild hyperhomocysteinemia seen in fasting conditions is due to mild impairment in the methylation pathway (i.e. folate or B12 deficiencies or methylenetetrahydrofolate reductase thermolability). Post-methionine-load hyperhomocysteinemia may be due to heterozygous cystathionine beta-synthase defect or B6 deficiency. Early studies with nonphysiological high homocysteine levels showed a variety of deleterious effects on endothelial or smooth muscle cells in culture. More recent studies with human beings and animals with mild hyperhomocysteinemia provided encouraging results in the attempt to understand the mechanism that underlies this relationship between mild elevations of plasma homocysteine and vascular disease. The studies with animal models indicated the possibility that the effect of elevated homocysteine is multifactorial, affecting both the vascular wall structure and the blood coagulation system.

Annu Rev Nutr. 1999;19:217-46.

Nicotinamide enhances repair of ultraviolet radiation-induced DNA damage in human keratinocytes and ex vivo skin.

Nicotinamide (vitamin B3) protects from ultraviolet (UV) radiation-induced carcinogenesis in mice and from UV-induced immunosuppression in mice and humans. Recent double-blinded randomized controlled Phase 2 studies in heavily sun-damaged individuals have shown that oral nicotinamide significantly reduces premalignant actinic keratoses, and may reduce new non-melanoma skin cancers. Nicotinamide is a precursor of nicotinamide adenine dinucleotide (NAD(+)), an essential coenzyme in adenosine triphosphate (ATP) production. Previously, we showed that nicotinamide prevents UV-induced ATP decline in HaCaT keratinocytes. Energy-dependent DNA repair is a key determinant of cellular survival after exposure to DNA-damaging agents such as UV radiation. Hence, in this study we investigated whether nicotinamide protection from cellular energy loss influences DNA repair. We treated HaCaT keratinocytes with nicotinamide and exposed them to low-dose solar-simulated UV (ssUV). Excision repair was quantified using an assay of unscheduled DNA synthesis. Nicotinamide increased both the proportion of cells undergoing excision repair and the repair rate in each cell. We then investigated ssUV-induced cyclobutane pyrimidine dimers (CPDs) and 8-oxo-7,8-dihydro-2’-deoxyguanosine (8oxoG) formation and repair by comet assay in keratinocytes and with immunohistochemistry in human skin. Nicotinamide reduced CPDs and 8oxoG in both models and the reduction appeared to be due to enhancement of DNA repair. These results show that nicotinamide enhances two different pathways for repair of UV-induced photolesions, supporting nicotinamide’s potential as an inexpensive, convenient and non-toxic agent for skin cancer chemoprevention.

Carcinogenesis. 2013 May;34(5):1144-9.

Nicotinamide prevents ultraviolet radiation-induced cellular energy loss.

UV radiation is carcinogenic by causing mutations in the skin and also by suppressing cutaneous antitumor immunity. We previously found nicotinamide (vitamin B3) to be highly effective at reducing UV-induced immunosuppression in human volunteers, with microarray studies on in vivo irradiated human skin suggesting that nicotinamide normalizes subsets of apoptosis, immune function and energy metabolism-related genes that are downregulated by UV exposure. Using human adult low calcium temperature keratinocytes, we further investigated nicotinamide’s effects on cellular energy metabolism. We found that nicotinamide prevented UV-induced cellular ATP loss and protected against UV-induced glycolytic blockade. To determine whether nicotinamide alters the effects of UV-induced oxidative stress posttranslationally, we also measured UV-induced reactive oxygen species (ROS). Nicotinamide had no effect on ROS formation, and at the low UV doses used in these studies, equivalent to ambient daily sun exposure, there was no evidence of apoptosis. Hence, nicotinamide appears to exert its UV protective effects on the skin via its role in cellular energy pathways.

Photochem Photobiol. 2010 Jul-Aug;86(4):942-8

Vitamin B Derivative (Nicotinamide)Appears to Reduce Skin Cancer Risk.

Nicotinamide, an amide form of vitamin B3, has shown the potential to treat a variety of dermatological conditions, including acne, rosacea, and atopic dermatitis. Recent studies have demonstrated the role of nicotinamide, in both topical and oral forms, as a chemopreventive agent against skin cancer. Its anti-carcinogenic role may be due to its ability to enhance DNA repair and prevent ultraviolet (UV)-induced immunosuppression, which is known to contribute to the progression of pre-malignant lesions. Furthermore, nicotinamide is a precursor of essential coenzymes for many important reactions in the body, including the production of nicotinamide adenine dinucleotide (NAD). NAD is a key coenzyme in the synthesis of adenosine triphosphate (ATP), which transports chemical energy within cells. Therefore, nicotinamide plays a significant role in supporting energy-dependent cellular processes, including DNA repair.

Skin Therapy Lett. 2017 Sep;22(5):1-4.

An abnormality of plasma amyloid protein precursor in Alzheimer’s disease.

beta A4 amyloid deposition in the brain, which is characteristic of Alzheimer’s disease (AD), may result from either overexpression of the amyloid protein precursor (APP) or failure of APP to be correctly processed. A blood marker reflecting this abnormal metabolism would be of diagnostic value and would provide a means of monitoring the efficacy of therapeutic interventions. We analyzed immunoblots of plasma APP enriched by heparin-Sepharose chromatography from patients with moderate to severe AD dementia (n = 34) and control subjects (n = 77) and found an approximately 50% increase in the proportion of 130-kd APP species in patients with AD (p less than 0.001), no difference in the 110-kd form, a 15 to 30% decrease in the 65-kd form (p less than 0.001), and a 20 to 35% decrease in the proportion of 42-kd APP (p less than 0.001). These species of APP were soluble, lacked the carboxyl terminus, and the 110- and 42-kd species were shown to be consistent with degradation products derived from the 130-kd species. A comparison of levels of 130-kd plasma APP from moderately to severely demented patients with AD and control subjects distinguished the two groups with a specificity of 87.0% and a sensitivity of 79.4%.

Ann Neurol. 1992 Jul;32(1):57-65.

Plasma amyloid precursor protein is decreased in Alzheimer’s disease.

Alzheimer’s disease is characterized by amyloid deposits whose major protein component is beta A4. beta A4 is a product of the amyloid precursor protein (APP). APP was assayed in partially purified plasma samples from 16 sporadic Alzheimer’s disease patients, 12 age-matched controls, 15 Down’s syndrome individuals aged 19-36 years and 8 young to middle-aged controls (22-51 years). 14 of the 16 Alzheimer’s disease patients had decreased plasma APP when compared with age-matched controls. 14 of the 15 Down’s syndrome individuals had similar levels of APP when compared with age-matched and elderly non-demented controls by immunoblotting, whereas one had levels of APP less than controls. Taken together with results from a previous report (Lancet 1992; 340: 453-454), the decreased plasma APP levels mirror the changes observed with cerebrospinal fluid APP levels in Alzheimer’s disease.

Neuroreport. 1993 Jun;4(6):757-9.

Folic acid, pyridoxine, and cyanocobalamin combination treatment and age-related macular degeneration in women: the Women’s Antioxidant and Folic Acid Cardiovascular Study.

BACKGROUND: Observational epidemiologic studies indicate a direct association between homocysteine concentration in the blood and the risk of age-related macular degeneration (AMD), but randomized trial data to examine the effect of therapy to lower homocysteine levels in AMD are lacking. Our objective was to examine the incidence of AMD in a trial of combined folic acid, pyridoxine hydrochloride (vitamin B(6)), and cyanocobalamin (vitamin B(12)) therapy. METHODS: We conducted a randomized, double-blind, placebo-controlled trial including 5,442 female health care professionals 40 years or older with preexisting cardiovascular disease or 3 or more cardiovascular disease risk factors. A total of 5,205 of these women did not have a diagnosis of AMD at baseline and were included in this analysis. Participants were randomly assigned to receive a combination of folic acid (2.5 mg/d), pyridoxine hydrochloride (50 mg/d), and cyanocobalamin (1 mg/d) or placebo. Our main outcome measures included total AMD, defined as a self-report documented by medical record evidence of an initial diagnosis after randomization, and visually significant AMD, defined as confirmed incident AMD with visual acuity of 20/30 or worse attributable to this condition. RESULTS: After an average of 7.3 years of treatment and follow-up, there were 55 cases of AMD in the combination treatment group and 82 in the placebo group (relative risk, 0.66; 95% confidence interval, 0.47-0.93 [P = .02]). For visually significant AMD, there were 26 cases in the combination treatment group and 44 in the placebo group (relative risk, 0.59; 95% confidence interval, 0.36-0.95 [P = .03]). CONCLUSIONS: These randomized trial data from a large cohort of women at high risk of cardiovascular disease indicate that daily supplementation with folic acid, pyridoxine, and cyanocobalamin may reduce the risk of AMD.

Arch Intern Med. 2009 Feb 23;169(4):335-41.

Oral nicotinamide protects against ultraviolet radiation-induced immunosuppression in humans.

Cutaneous immunity, which is a key defence against the development of skin cancers, is suppressed by even small doses of ultraviolet (UV) radiation. Preventing this UV-induced immunosuppression may therefore reduce the incidence of skin cancer. Nicotinamide (vitamin B3) has immune-protective and cancer-preventive effects against UV radiation in mice, and we have shown previously that topical nicotinamide is immune protective in humans. Using the Mantoux model of skin immunity in healthy volunteers, we compared oral nicotinamide to placebo (both administered for 1 week) in a randomized, double-blinded, crossover design against the effects of solar-simulated ultraviolet (ssUV) radiation on delayed-type hypersensitivity to tuberculin purified protein derivative. Discrete areas of the back were irradiated with low doses of ssUV daily for three consecutive days. Immunosuppression, calculated as the difference in Mantoux-induced erythema of irradiated sites compared with unirradiated control sites, was determined in volunteers taking oral nicotinamide and placebo. Significant immunosuppression occurred in an UV dose-dependent manner in the presence of placebo. Oral nicotinamide, at doses of either 1,500 or 500 mg daily, was well tolerated and significantly reduced UV immunosuppression with no immune effects in unirradiated skin. Oral nicotinamide is safe and inexpensive and looks promising as a chemopreventive supplement for reducing the immunosuppressive effects of sunlight.

Carcinogenesis. 2009 Jan;30(1):101-5.


Senolytics improve physical function and increase lifespan in old age.

Physical function declines in old age, portending disability, increased health expenditures, and mortality. Cellular senescence, leading to tissue dysfunction, may contribute to these consequences of aging, but whether senescence can directly drive age-related pathology and be therapeutically targeted is still unclear. Here we demonstrate that transplanting relatively small numbers of senescent cells into young mice is sufficient to cause persistent physical dysfunction, as well as to spread cellular senescence to host tissues. Transplanting even fewer senescent cells had the same effect in older recipients and was accompanied by reduced survival, indicating the potency of senescent cells in shortening health- and lifespan. The senolytic cocktail, dasatinib plus quercetin, which causes selective elimination of senescent cells, decreased the number of naturally occurring senescent cells and their secretion of frailty-related proinflammatory cytokines in explants of human adipose tissue. Moreover, intermittent oral administration of senolytics to both senescent cell-transplanted young mice and naturally aged mice alleviated physical dysfunction and increased post-treatment survival by 36% while reducing mortality hazard to 65%. Our study provides proof-of-concept evidence that senescent cells can cause physical dysfunction and decreased survival even in young mice, while senolytics can enhance remaining health- and lifespan in old mice.

Nat Med. 2018 Aug;24(8):1246-1256.

Clearance of senescent glial cells prevents tau-dependent pathology and cognitive decline.

Cellular senescence, which is characterized by an irreversible cell-cycle arrest1 accompanied by a distinctive secretory phenotype2, can be induced through various intracellular and extracellular factors. Senescent cells that express the cell cycle inhibitory protein p16INK4A have been found to actively drive naturally occurring age-related tissue deterioration3,4 and contribute to several diseases associated with ageing, including atherosclerosis5 and osteoarthritis6. Various markers of senescence have been observed in patients with neurodegenerative diseases7-9; however, a role for senescent cells in the aetiology of these pathologies is unknown. Here we show a causal link between the accumulation of senescent cells and cognition-associated neuronal loss. We found that the MAPTP301SPS19 mouse model of tau-dependent neurodegenerative disease10 accumulates p16INK4A-positive senescent astrocytes and microglia. Clearance of these cells as they arise using INK-ATTAC transgenic mice prevents gliosis, hyperphosphorylation of both soluble and insoluble tau leading to neurofibrillary tangle deposition, and degeneration of cortical and hippocampal neurons, thus preserving cognitive function. Pharmacological intervention with a first-generation senolytic modulates tau aggregation. Collectively, these results show that senescent cells have a role in the initiation and progression of tau-mediated disease, and suggest that targeting senescent cells may provide a therapeutic avenue for the treatment of these pathologies.

Nature. 2018 Oct;562(7728):578-582.

Cellular Senescence: A Translational Perspective.

Cellular senescence entails essentially irreversible replicative arrest, apoptosis resistance, and frequently acquisition of a pro-inflammatory, tissue-destructive senescence-associated secretory phenotype (SASP). Senescent cells accumulate in various tissues with aging and at sites of pathogenesis in many chronic diseases and conditions. The SASP can contribute to senescence-related inflammation, metabolic dysregulation, stem cell dysfunction, aging phenotypes, chronic diseases, geriatric syndromes, and loss of resilience. Delaying senescent cell accumulation or reducing senescent cell burden is associated with delay, prevention, or alleviation of multiple senescence-associated conditions. We used a hypothesis-driven approach to discover pro-survival Senescent Cell Anti-apoptotic Pathways (SCAPs) and, based on these SCAPs, the first senolytic agents, drugs that cause senescent cells to become susceptible to their own pro-apoptotic microenvironment. Several senolytic agents, which appear to alleviate multiple senescence-related phenotypes in pre-clinical models, are beginning the process of being translated into clinical interventions that could be transformative.

EBioMedicine. 2017 Jul;21:21-28.

The Achilles’ heel of senescent cells: from transcriptome to senolytic drugs.

The healthspan of mice is enhanced by killing senescent cells using a transgenic suicide gene. Achieving the same using small molecules would have a tremendous impact on quality of life and the burden of age-related chronic diseases. Here, we describe the rationale for identification and validation of a new class of drugs termed senolytics, which selectively kill senescent cells. By transcript analysis, we discovered increased expression of pro-survival networks in senescent cells, consistent with their established resistance to apoptosis. Using siRNA to silence expression of key nodes of this network, including ephrins (EFNB1 or 3), PI3Kd, p21, BCL-xL, or plasminogen-activated inhibitor-2, killed senescent cells, but not proliferating or quiescent, differentiated cells. Drugs targeting these same factors selectively killed senescent cells. Dasatinib eliminated senescent human fat cell progenitors, while quercetin was more effective against senescent human endothelial cells and mouse BM-MSCs. The combination of dasatinib and quercetin was effective in eliminating senescent MEFs. In vivo, this combination reduced senescent cell burden in chronologically aged, radiation-exposed, and progeroid Ercc1(-/D) mice. In old mice, cardiac function and carotid vascular reactivity were improved 5 days after a single dose. Following irradiation of one limb in mice, a single dose led to improved exercise capacity for at least 7 months following drug treatment. Periodic drug administration extended healthspan in Ercc1(-/∆) mice, delaying age-related symptoms and pathology, osteoporosis, and loss of intervertebral disk proteoglycans. These results demonstrate the feasibility of selectively ablating senescent cells and the efficacy of senolytics for alleviating symptoms of frailty and extending healthspan.

Aging Cell. 2015 Aug;14(4):644-58.

Short-term High Dose of Quercetin and Resveratrol Alters Aging Markers in Human Kidney Cells.

BACKGROUND: Hyperglycemia-mediated oxidative stress implicates in etiology of kidney cell aging and diabetic nephropathy. We evaluated the effects of different doses of resveratrol and quercetin and their combination therapy on aging marker in human kidney cell culture under hyperglycemia condition. METHODS: Human embryonic kidney cell (HEK-293) was cultured in Dulbecco’s Modified Eagle Medium (DMEM) containing 100 mM (18 mg/L) for 24 h. The cells were treated with resveratrol (2.5, 5, 10 µm), quercetin (3, 6, 12 µm), and combination of these (R 2.5 µm, Q 3 µm) and (R 5 µm, Q 6 µm) and (R 10 µm, Q 12 µm) for 48 h, and then, cells were lysed to access RNA and lysate. RESULTS:  The analysis of data showed that beta-galactosidase enzyme gene expression as an aging marker in all treatment groups has reduced in a dose-dependent manner. Gene expression of Sirtuin1 and thioredoxin (Trx) in all treated groups in comparison to control group increased in a dose-dependent fashion. Trx interacting protein (TXNIP) gene expression decreased in a dose-dependent manner in all treated groups, especially in resveratrol and combination therapy. CONCLUSIONS: According to the results of this research, quercetin, resveratrol, and especially combination treatments with increased expression levels of antioxidants, can reduce aging markers in HEK cell line in hyperglycemia conditions. These results lead us to use flavonoids such as resveratrol for anti-aging potential.

Int J Prev Med. 2017 Aug 31;8:64.

Anti-ageing and rejuvenating effects of quercetin.

Homeostasis is a key feature of the cellular lifespan. Its maintenance influences the rate of ageing and it is determined by several factors, including efficient proteolysis. The proteasome is the major cellular proteolytic machinery responsible for the degradation of both normal and damaged proteins. Alterations of proteasome function have been recorded in various biological phenomena including ageing and replicative senescence. Proteasome activities and function are decreased upon replicative senescence, whereas proteasome activation confers enhanced survival against oxidative stress, lifespan extension and maintenance of the young morphology longer in human primary fibroblasts. Several natural compounds possess anti-ageing/anti-oxidant properties. In this study, we have identified quercetin (QUER) and its derivative, namely quercetin caprylate (QU-CAP) as a proteasome activator with anti-oxidant properties that consequently influence cellular lifespan, survival and viability of HFL-1 primary human fibroblasts. Moreover, when these compounds are supplemented to already senescent fibroblasts, a rejuvenating effect is observed. Finally, we show that these compounds promote physiological alterations when applied to cells (i.e. whitening effect). In summary, these data demonstrate the existence of naturally occurring anti-ageing products that can be effectively used through topical application.

Exp Gerontol. 2010 Oct;45(10):763-71.

The Effect of Quercetin on Inflammatory Factors and Clinical Symptoms in Women with Rheumatoid Arthritis: A Double-Blind, Randomized Controlled Trial.

OBJECTIVE: Previous studies have shown that the bioflavonoid quercetin has anti-inflammatory and anti-nociceptive effects. We investigated the effect of quercetin supplementation on inflammation, disease severity, and clinical symptoms in women with rheumatoid arthritis (RA). METHODS: The present study was a randomized, double-blind, placebo-controlled clinical trial in which 50 women with RA were allocated into a quercetin (500 mg/day) or placebo group for 8 weeks. Plasma levels of high-sensitivity tumor necrosis factor-a (hs-TNFa), erythrocyte sedimentation rate (ESR), clinical symptoms including early morning stiffness (EMS), morning and after-activity pain, and tender (TSC) and swollen joint counts (SJC) were determined. Disease activity and functional disability were assessed by Disease Activity Score 28 (DAS-28), physician global assessment (PGA), and a health assessment questionnaire (HAQ) at the beginning and end of the study. RESULTS: Quercetin supplementation for 8 weeks significantly reduced EMS, morning pain, and after-activity pain (p < 0.05). DAS-28 and HAQ scores decreased in the quercetin group compared to placebo and the number of patients with active disease significantly decreased in the quercetin group. Plasma hs-TNFa level was significantly reduced in the quercetin group compared to placebo (p < 0.05). There were no significant differences in TJC and SJC between groups but TJC significantly decreased in the quercetin group after the intervention. Supplementation had an effect on ESR but it was not significant (p > 0.05). CONCLUSIONS: Five hundred milligrams per day quercetin supplementation for 8 weeks resulted in significant improvements in clinical symptoms, disease activity, hs-TNFa, and HAQ in women with RA.

J Am Coll Nutr. 2017 Jan;36(1):9-15.

Quercetin mediated lifespan extension in Caenorhabditis elegans is modulated by age-1, daf-2, sek-1 and unc-43.

The nematode Caenorhabditis elegans responds to flavonoid-rich diets with improved health and longevity. The precise mechanism(s) responsible for this remains to be identified, but is believed to be linked to the highly antioxidative properties of flavonoids. This study provides a dissection of lifespan modulation by the flavonoid quercetin. In detail, quercetin was shown not to act as a simple antimicrobial agent or exclusively via radical scavenging capacities. Likewise, lifespan extension had no effect on reproduction and body length. Furthermore, neither a caloric restriction mimetic nor a sirtuin (sir-2.1) dependence was identified as a likely mode of action. However, four genes were pinpointed to be required for the quercetin derived lifespan extension, namely age-1, daf-2, unc-43 and sek-1. The latter two have, to date, not been linked to quercetin-mediated lifespan extension.

Biogerontology.2009 Oct;10(5):565-78.

Black tea theaflavins extend the lifespan of fruit flies.

Black tea extract (BTE) is a mixture of epicatechins and theaflavins. The present study investigated the effect of BTE on the lifespan of Drosophila melanogaster. Results showed the mean lifespan was significantly extended from 51 to 56days upon BTE treatment. Gene expression of superoxide dismutase (SOD1 and SOD2), catalase (CAT), and methuselah (MTH) was characterized by an increase in young and then a decrease in aged fruit flies. Higher gene expression of SOD1 and CAT was observed in the BTE-treated group than the control flies. However, BTE exerted a minimal effect on the expression of SOD2 and MTH genes. Dietary fat could induce oxidative stress and shorten the maximum lifespan to 15days, while addition of 10mg/ml BTE into diet extended it to 28days. Paraquat and H(2)O(2) challenge tests demonstrated that BTE prolonged the survival time only for Oregon-R wild type flies but not for SOD(n108) or Cat(n1) mutants. This suggests that the lifespan-prolonging activity of BTE is mediated at least in part through SOD and CAT.

Exp Gerontol. 2009 Dec;44(12):773-83.

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