Patent Publication Number: US-2023133114-A1

Title: Compositions and methods containing reduced nicotinamide riboside for prevention and treatment of viral and bacterial infections

Description:
FIELD OF THE INVENTION 
     The present invention provides compounds and compositions containing reduced nicotinamide riboside for use in promoting protective immunity leading to bacterial and viral pathogen clearance and to prevent and/or treat bacterial and/or viral infections. 
     BACKGROUND TO THE INVENTION 
     The immune system is highly adapted to provide host defense against pathogens. Indeed, an appropriate immune response leads to pathogen clearance while limiting immune mediated pathology. Macrophages with antimicrobial activity is one mechanism that prevents dissemination of bacteria beyond the intestinal barrier (Smith PD, et al. Intestinal macrophages and response to microbial encroachment. Mucosal Immunol 2011;4(1):31-42.). Macrophages are critical for protection against infections in the lung (Aegerter 2020) and that the killing mechanisms of macrophages are conserved independent of the pathogens. For example, macrophage LC3-associated phagocytosis is critical for protection against Salmonella (gut pathogen- Schulthess 2018) and S. pneumoniae (lung pathogen -Inomata 2020) with similar protective mediators required for Salmonella and M. tuberculosis (lung pathogen) resistance (Serbina 2008). 
     Also, pulmonary or respiratory diseases of the lung encompass conditions affecting the lung and its tissues that make gas exchange difficult in air-breathing animals. They involve respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, and the nerves and muscles of respiration. Respiratory diseases and conditions may be acute and self-limiting, such as the common cold, to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, asthma and lung cancer. 
     Nicotinamide adenine dinucleotide (NAD+) is an important regulator of cellular metabolism and homeostasis for the respiratory system since NAD+ acts as a cofactor for a number of enzymes and regulation of NAD+ levels may have therapeutic benefits through its effect on NAD+-dependent enzymes. On the cellular level, NAD+ influences mitochondrial biogenesis, transcription and organization of extracellular matrix components. 
     Previous investigations have highlighted the important role of NAD+ in lung tissue in response to hyperoxia and niacin deficiency (Rawling et al. (1996) as well as in lung cancer (Touat et al. (2018). Lower NAD+ levels may be deleterious for pulmonary health while higher NAD+ levels may augment pulmonary health. 
     Therefore, there is an urgent unmet need to address viral and bacterial infections with new compounds, compositions and methods of prevention and/or treatment which influence NAD+. 
     SUMMARY OF THE INVENTION 
     The present invention provides compounds and compositions for use in promoting protective immunity and/or for preventing and/or treating bacterial or viral infections and/or for limiting immune mediated pathology following infection. 
     Advantageously compounds for use according to the present invention have been found to increase anti-bacterial macrophage response. 
     In another embodiment, the present invention provides a unit dosage form of a composition consisting of reduced nicotinamide riboside, the unit dosage form contains an effective amount of the reduced nicotinamide riboside to increase immune response in an individual. 
     In one embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to treat and/or prevent gastrointestinal infections, respiratory infections (upper and/or lower respiratory tract infections), urinary infections, including both bacterial and viral infections. 
     In another embodiment of the invention, the composition is a nutritional composition selected from a: food or beverage product, including food additives, food ingredients, functional foods, dietary supplements, medical foods, nutraceuticals, oral nutritional supplements (ONS) or food supplements. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Definitions 
     All percentages expressed herein are by weight of the total weight of the composition unless expressed otherwise. As used herein, “about,” “approximately” and “substantially” are understood to refer to numbers in a range of numerals, for example the range of -10% to +10% of the referenced number, preferably -5% to +5% of the referenced number, more preferably —1% to +1% of the referenced number, most preferably -0.1% to +0.1% of the referenced number. 
     All numerical ranges herein should be understood to include all integers, whole or fractions, within the range. Moreover, these numerical ranges should be construed as providing support for a claim directed to any number or subset of numbers in that range. For example, a disclosure of from 1 to 10 should be construed as supporting a range of from 1 to 8, from 3 to 7, from 1 to 9, from 3.6 to 4.6, from 3.5 to 9.9, and so forth. 
     As used in this invention and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component” or “the component” includes two or more components. 
     The words “comprise,” “comprises” and “comprising” are to be interpreted inclusively rather than exclusively. Likewise, the terms “include,” “including” and “or” should all be construed to be inclusive, unless such a construction is clearly prohibited from the context. Nevertheless, the compositions disclosed herein may lack any element that is not specifically disclosed herein. Thus, a disclosure of an embodiment using the term “comprising” includes a disclosure of embodiments “consisting essentially of” and “consisting of” the components identified. Any embodiment disclosed herein can be combined with any other embodiment disclosed herein. 
     Where used herein, the terms “example” and “such as,” particularly when followed by a listing of terms, are merely exemplary and illustrative and should not be deemed to be exclusive or comprehensive. As used herein, a condition “associated with” or “linked with” another condition means the conditions occur concurrently, preferably means that the conditions are caused by the same underlying condition, and most preferably means that one of the identified conditions is caused by the other identified condition. 
     The terms “food,” “food product” and “food composition” mean a product or composition that is intended for ingestion by an individual such as a human and provides at least one nutrient to the individual. A food product typically includes at least one of a protein, a lipid, a carbohydrate and optionally includes one or more vitamins and minerals. The term “beverage” or “beverage product” means a liquid product or liquid composition that is intended to be ingested orally by an individual such as a human and provides at least one nutrient to the individual. 
     The compositions of the present disclosure, including the many embodiments described herein, can comprise, consist of, or consist essentially of the elements disclosed herein, as well as any additional or optional ingredients, components, or elements described herein or otherwise useful in a diet. 
     As used herein, the term “isolated” means removed from one or more other compounds or components with which the compound may otherwise be found, for example as found in nature. For example, “isolated” preferably means that the identified compound is separated from at least a portion of the cellular material with which it is typically found in nature. In an embodiment, an isolated compound is free from any other compound. 
     “Prevention” includes reduction of risk, incidence and/or severity of a condition or disorder. The terms “treatment,” “treat” and “to alleviate” include both prophylactic or preventive treatment (that prevent and/or slow the development of a targeted pathologic condition or disorder) and curative, therapeutic or disease-modifying treatment, including therapeutic measures that cure, slow down, lessen symptoms of, and/or halt progression of a diagnosed pathologic condition or disorder; and treatment of patients at risk of contracting a disease or suspected to have contracted a disease, as well as patients who are ill or have been diagnosed as suffering from a disease or medical condition. The term does not necessarily imply that a subject is treated until total recovery. The terms “treatment” and “treat” also refer to the maintenance and/or promotion of health in an individual not suffering from a disease but who may be susceptible to the development of an unhealthy condition. The terms “treatment,” “treat” and “to alleviate” are also intended to include the potentiation or otherwise enhancement of one or more primary prophylactic or therapeutic measure. The terms “treatment,” “treat” and “to alleviate” are further intended to include the dietary management of a disease or condition or the dietary management for prophylaxis or prevention a disease or condition. A treatment can be patient- or doctor-related. 
     The term “promotion”, “to promote”, “promoting” means enhancing, boosting, or accelerating a physiological response, for example protective immunity. 
     The term “unit dosage form,” as used herein, refers to physically discrete units suitable as unitary dosages for human and animal subjects, each unit containing a predetermined quantity of the composition disclosed herein in an amount sufficient to produce the desired effect, in association with a pharmaceutically acceptable diluent, carrier or vehicle. The specifications for the unit dosage form depend on the particular compounds employed, the effect to be achieved, and the pharmacodynamics associated with each compound in the host. 
     As used herein, an “effective amount” is an amount that prevents a deficiency, treats a disease or medical condition in an individual, or, more generally, reduces symptoms, manages progression of the disease, or provides a nutritional, physiological, or medical benefit to the individual. The relative terms “improve,” “increase,” “enhance,” “promote” and the like refer to the effects of the composition disclosed herein, namely a composition comprising reduced nicotinamide riboside, relative to a composition not having nicotinamide riboside but otherwise identical. As used herein, “promoting” refers to enhancing or inducing relative to the level before administration of the composition disclosed herein. 
     As used herein “reduced nicotinamide riboside” may also be known as protonated nicotinamide riboside, dihydronicotinamide riboside, dihydro-1-beta-D-ribofuranosyl-3-pyridinecarboxamide, or 1-(beta-D-ribofuranosyl)-dihydronicotinamide. A description of the synthesis of reduced nicotinamide riboside is given in Example 1. The location of the protonation site can give rise to different forms of “reduced nicotinamide riboside”. For example: 1,4-dihydro-1-beta-D-ribofuranosyl-3-pyridinecarboxamide; 1,2-dihydro-1-beta-D-ribofuranosyl-3-pyridinecarboxamide; and 1,6-dihydro-1-beta-D-ribofuranosyl-3-pyridinecarboxamide (Makarov and Migaud, 2019). 
     Embodiments 
     The present invention provides compounds and compositions containing reduced nicotinamide riboside. Another aspect of the present invention is a unit dosage form of a composition consisting of reduced nicotinamide riboside, and the unit dosage form contains the reduced nicotinamide riboside in an amount effective to increase immune response, in particular antimicrobial immune response, in subject in need thereof. 
     Nicotinamide adenine dinucleotide (NAD+) is considered a coenzyme, and essential cofactor in cellular redox reactions to produce energy. It plays critical roles in energy metabolism, as the oxidation of NADH to NAD+ facilitates hydride-transfer, and consequently ATP generation through mitochondrial oxidative phosphorylation. It also acts as a degradation substrate for multiple enzymes (Canto, C. et al. 2015; Imai, S. et al. 2000; Chambon, P. et al. 1963; Lee, H.C. et al. 1991). 
     Mammalian organisms can synthesize NAD+ from four different sources. First, NAD+ can be obtained from tryptophan through the 10-step de novo pathway. Secondly, Nicotinic acid (NA) can also be transformed into NAD+ through the 3-step Preiss-Handler path, which converges with the de novo pathway. Thirdly, intracellular NAD+ salvage pathway from nicotinamide (NAM) constitutes the main path by which cells build NAD+, and occurs through a 2-step reaction in which NAM is first transformed into NAM-mononucleotide (NMN) via the catalytic activity of the NAM-phosphoribosyltransferase (NAMPT) and then converted to NAD+ via NMN adenylyltransferase (NMNAT) enzymes. Finally, Nicotinamide Riboside (NR) constitutes yet a fourth path to NAD+, characterized by the initial phosphorylation of NR into NMN by NR kinases (NRKs) (Breganowski, P. et al.; 2004). 
     An important difference between NR and NRH is that they go through different synthetic pathways to synthesize NAD+. For example, NRH does not use the NRK-1 enzyme pathway (J. Giroud-Gerbetant et al. 2019). Instead, NRH uses a path initiated by adenosine kinase, which does not involve NR. Therefore, the abilities of NR and NRH are independent and unrelated. 
     Five molecules previously have been known to act as direct extracellular NAD+ precursors: tryptophan, nicotinic acid (NA), nicotinamide (NAM), nicotinic acid riboside (NaR) and nicotinamide riboside (NR). The reduction of the NR molecule to NRH confers it not only a much stronger capacity to increase intracellular NAD+ levels, but also a different selectivity in terms of its cellular use. This reduced form of NR has the advantage of being more potent and faster than nicotinamide riboside (NR). The present invention demonstrates that NRH is protected against degradation in plasma and can be detected in circulation after oral administration. These advantages of the invention support its therapeutic efficacy. 
     The increase in anti-bacterial macrophage response can provide one or more benefits to the individual, for example a human (e.g., a human undergoing medical treatment), a pet or a horse (e.g., a pet or horse undergoing medical treatment), or cattle or poultry (e.g., cattle or poultry being used in agriculture) with respect to the prevention or treatment of bacterial or viral infections and/or for limiting immune mediated pathology following infection and/or for promoting protective immunity to the individual. 
     For non-human mammals such as rodents, some embodiments comprise administering an amount of the composition that provides 1.0 mg to 1.0 g of the reduced nicotinamide riboside / kg of body weight of the non-human mammal, preferably 10 mg to 500 mg of the reduced nicotinamide riboside / kg of body weight of the non-human mammal, more preferably 25 mg to 400 mg of the reduced nicotinamide riboside / kg of body weight of the mammal, most preferably 50 mg to 300 mg of the reduced nicotinamide riboside / kg of body weight of the non-human mammal. 
     For humans, some embodiments comprise administering an amount of the composition that provides 1.0 mg to 10.0 g of the reduced nicotinamide riboside / kg of body weight of the human, preferably 10 mg to 5.0 g of the reduced nicotinamide riboside / kg of body weight of the human, more preferably 50 mg to 2.0 g of the reduced nicotinamide riboside / kg of body weight of the human, most preferably 100 mg to 1.0 g of the reduced nicotinamide riboside / kg of body weight of the human. 
     In some embodiments, at least a portion of the reduced nicotinamide riboside is isolated from natural plant sources. Additionally or alternatively, at least a portion of reduced nicotinamide riboside can be chemically synthesized. For example, according to Example 1 described below. 
     As used herein, a “composition consisting essentially of reduced nicotinamide riboside” contains reduced nicotinamide riboside and does not include, or is substantially free of, or completely free of, any additional compound that affects NAD+ production other than the “reduced nicotinamide riboside”. In a particular non-limiting embodiment, the composition consists of the reduced nicotinamide riboside and an excipient or one or more excipients. 
     In some embodiments, the composition consisting essentially of reduced nicotinamide riboside is optionally substantially free or completely free of other NAD+ precursors, such as nicotinamide riboside. 
     As used herein, “substantially free” means that any of the other compounds present in the composition is no greater than 1.0 wt.% relative to the amount of reduced nicotinamide riboside, preferably no greater than 0.1 wt.% relative to the amount of reduced nicotinamide riboside, more preferably no greater than 0.01 wt.% relative to the amount of reduced nicotinamide riboside, most preferably no greater than 0.001 wt.% relative to the amount of reduced nicotinamide riboside. 
     Treatment 
     It is to be appreciated that all references herein to treatment include curative, palliative and prophylactic treatment. Treatment may also include arresting progression in the severity of a disease. 
     Both human and veterinary treatments are within the scope of the invention. 
     Within the context of the present invention, the term “promotion of protective immunity″” means one or more of the following: prevention of infection, anti-pathogen activity, limiting pathogen expansion, promoting pathogen clearance, restriction of pathogen dissemination, recovery from infection, reducing the risk of secondary infection, and/or limiting immune mediated pathology following infection. Promoting protective immunity can be defined by the three levels of immune defence against pathogens (i) mucosal barrier functions of the lung and gastrointestinal tract, (ii) the innate immune response and in particular macrophages with antimicrobial activity and (iii) the adaptive immune response including CD8 T cell activation, which increases anti-viral immunity in the lung. 
     Within the context of the present invention, the term “infections” includes gastrointestinal infections, respiratory infections (upper and/or lower respiratory tract infections), urinary infections, including both bacterial and viral infections. 
     Within the context of the present invention, the term gastrointestinal infection means an infection caused by enteropathogens to include but is not limited to Salmonella, Shigella, C. difficile and/or Citrobacter. 
     Within the context of the present invention, the term “viral infections” means infections caused by viruses, such as for example influenza infection, rotavirus infection and the like. Both innate and adaptive immunity contribute to protective immunity to viral infections. 
     Within the context of the present invention, the term Respiratory tract infections (RTIs) refers to infectious diseases involving the respiratory tract. An infection of this type usually is further classified as an upper respiratory tract infection (URI or URTI) or a lower respiratory tract infection (LRI or LRTI). Lower respiratory infections, such as pneumonia, tend to be far more severe than upper respiratory infections, such as the common cold. Upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, or larynx. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. Most infections are viral in nature, and in other instances, the cause is bacterial. The lower respiratory tract consists of the trachea (windpipe), bronchial tubes, bronchioles, and the lungs. LRIs are bronchitis and pneumonia. 
     Within the context of the present invention, Pulmonary Diseases and Conditions include:
     i) Obstructive lung diseases and conditions, typically affecting (i) the airways and/or (ii) the alveoli.   ii) Lung Airway obstruction diseases and conditions, which affect the trachea, bronchi, and bronchioles which in turn branch to become progressively smaller tubes throughout the lungs. Conditions and diseases that affect the lung airways include, for example: asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis, emphysema, acute bronchitis and cystic fibrosis.   iii) Lung Alveolar obstruction disease and conditions Alveoli are the air sacs make up most of the lung tissue. Disease and conditions that affect the lung alveoli include, for example, pneumonia, tuberculosis, etc.   

     It may be appreciated that the compounds, compositions and methods of the present invention may be beneficial to prevent and/or treat bacteria and/or viral infections mentioned above, in particular, to maintain or improve organ tissue function. 
     Influenza affects both the upper and lower respiratory tracts, but more dangerous strains such as the highly pernicious H5N1 tend to bind to receptors deep in the lungs. 
     Composition for Use 
     In each of the compositions and methods disclosed herein, the composition is preferably a food product or beverage product, including food additives, food ingredients, functional foods, dietary supplements, medical foods, nutraceuticals, oral nutritional supplements (ONS) or food supplements. 
     The composition can be administered at least one day per week, preferably at least two days per week, more preferably at least three or four days per week (e.g., every other day), most preferably at least five days per week, six days per week, or seven days per week. The time period of administration can be at least one week, preferably at least one month, more preferably at least two months, most preferably at least three months, for example at least four months. In some embodiments, dosing is at least daily; for example, a subject may receive one or more doses daily, in an embodiment a plurality of doses per day. In some embodiments, the administration continues for the remaining life of the individual. In other embodiments, the administration occurs until no detectable symptoms of the medical condition remain. In specific embodiments, the administration occurs until a detectable improvement of at least one symptom occurs and, in further cases, continues to remain ameliorated. 
     The compositions disclosed herein may be administered to the subject enterally, e.g., orally, or parenterally. Non-limiting examples of parenteral administration include intravenously, intramuscularly, intraperitoneally, subcutaneously, intraarticularly, intrasynovially, intraocularly, intrathecally, topically, and inhalation. As such, non-limiting examples of the form of the composition include natural foods, processed foods, natural juices, concentrates and extracts, injectable solutions, microcapsules, nano-capsules, liposomes, plasters, inhalation forms, nose sprays, nosedrops, eyedrops, sublingual tablets, and sustained-release preparations. 
     The compositions disclosed herein can use any of a variety of formulations for therapeutic administration. More particularly, pharmaceutical compositions can comprise appropriate pharmaceutically acceptable carriers or diluents and may be formulated into preparations in solid, semi-solid, liquid or gaseous forms, such as tablets, capsules, powders, granules, ointments, solutions, suppositories, injections, inhalants, gels, microspheres, and aerosols. As such, administration of the composition can be achieved in various ways, including oral, buccal, rectal, parenteral, intraperitoneal, intradermal, transdermal, and intratracheal administration. The active agent may be systemic after administration or may be localized by the use of regional administration, intramural administration, or use of an implant that acts to retain the active dose at the site of implantation. 
     In pharmaceutical dosage forms, the compounds may be administered as their pharmaceutically acceptable salts. They may also be used in appropriate association with other pharmaceutically active compounds. The following methods and excipients are merely exemplary and are in no way limiting. 
     For oral preparations, the compounds can be used alone or in combination with appropriate additives to make tablets, powders, granules or capsules, for example, with conventional additives, such as lactose, mannitol, corn starch or potato starch; with binders, such as crystalline cellulose, cellulose functional derivatives, acacia, corn starch or gelatins; with disintegrators, such as corn starch, potato starch or sodium carboxymethylcellulose; with lubricants, such as talc or magnesium stearate; and if desired, with diluents, buffering agents, moistening agents, preservatives and flavoring agents. 
     The compounds can be formulated into preparations for injections by dissolving, suspending or emulsifying them in an aqueous or non-aqueous solvent, such as vegetable or other similar oils, synthetic aliphatic acid glycerides, esters of higher aliphatic acids or propylene glycol; and if desired, with conventional, additives such as solubilizers, isotonic agents, suspending agents, emulsifying agents, stabilizers and preservatives. 
     The compounds can be utilized in an aerosol formulation to be administered by inhalation. For example, the compounds can be formulated into pressurized acceptable propellants such as dichlorodifluoromethane, propane, nitrogen and the like. 
     Furthermore, the compounds can be made into suppositories by mixing with a variety of bases such as emulsifying bases or water-soluble bases. The compounds can be administered rectally by a suppository. The suppository can include a vehicle such as cocoa butter, carbowaxes and polyethylene glycols, which melt at body temperature, yet are solidified at room temperature. 
     Unit dosage forms for oral or rectal administration such as syrups, elixirs, and suspensions may be provided wherein each dosage unit, for example, teaspoonful, tablespoonful, tablet or suppository, contains a predetermined amount of the composition. Similarly, unit dosage forms for injection or intravenous administration may comprise the compounds in a composition as a solution in sterile water, normal saline or another pharmaceutically acceptable carrier, wherein each dosage unit, for example, mL or L, contains a predetermined amount of the composition containing one or more of the compounds. 
     Compositions intended for a non-human animal include food compositions to supply the necessary dietary requirements for an animal, animal treats (e.g., biscuits), and/or dietary supplements. The compositions may be a dry composition (e.g., kibble), semi-moist composition, wet composition, or any mixture thereof. In one embodiment, the composition is a dietary supplement such as a gravy, drinking water, beverage, yogurt, powder, granule, paste, suspension, chew, morsel, treat, snack, pellet, pill, capsule, tablet, or any other suitable delivery form. The dietary supplement can comprise a high concentration of the UFA and NORC, and B vitamins and antioxidants. This permits the supplement to be administered to the animal in small amounts, or in the alternative, can be diluted before administration to an animal. The dietary supplement may require admixing, or can be admixed with water or other diluent prior to administration to the animal. 
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     Aegerter H. et al. 2020. Influenza-induced monocyte-derived alveolar macrophages confer prolonged antibacterial protection. Nat Immunol. February; 21(2):145-157. 
     Bieganowski, P. and C. Brenner, 2004. Discoveries of nicotinamide riboside as a nutrient and conserved NRK genes establish a Preiss-Handler independent route to NAD+ in fungi and humans. Cell. 117(4): 495-502. 
     Canto, C., K.J. Menzies, and J. Auwerx, 2015. NAD(+) Metabolism and the Control of Energy Homeostasis: A Balancing Act between Mitochondria and the Nucleus. Cell Metab. 22(1): 31-53. 
     Chambon, P., J.D. Weill, and P. Mandel, 1963. Nicotinamide mononucleotide activation of new DNA-dependent polyadenylic acid synthesizing nuclear enzyme. Biochem Biophys Res Commun. 1139-43. 
     Chen, L.K., et al. (2014). Sarcopenia in Asia: consensus report of the Asian Working Group for Sarcopenia. Journal of the American Medical Directors Association 15, 95-101. 
     Clark RV, Walker AC, O&#39;Connor-Semmes RL, Leonard MS, Miller RR, Stimpson SA, Turner SM, Ravussin E, Cefalu WT, Hellerstein MK, Evans WJ (1985). Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans. J Appl Physiol. Jun 15; 116(12):1605-13. 
     Cruz-Jentoft, A.J., Baeyens, J.P., Bauer, J.M., Boirie, Y., Cederholm, T., Landi, F., Martin, F.C., Michel, J.P., Rolland, Y., Schneider, S.M., et al. (2010). Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People. Age Ageing 39, 412-423. 
     Fearon et al. (2011) Definition and classification of cancer cachexia: an international consensus. Lancet Oncology, 12, 489-495. 
     Giroud-Gerbetant, J. et al. (2019) A reduced form of nicotinamide riboside defines a new pathway for synthesis of NAD+ and acts as an orally bioavailable NAD+ precursor, Molecular Metabolism, Vol.30, pp.192-202. 
     Goody, MF. And Henry, C.A. (2018) A need for NAD+ in muscle development, homeostasis and aging. Skelet Muscle, 8:9. 
     Imai, S., C.M. Armstrong, M. Kaeberlein, and L. Guarente, 2000. Transcriptional silencing and longevity protein Sir2 is an NAD-dependent histone deacetylase. Nature. 403(6771): 795-800. 
     Lee, H.C. and R. Aarhus, 1991. ADP-ribosyl cyclase: an enzyme that cyclizes NAD+ into a calcium-mobilizing metabolite. Cell Regul. 2(3): 203-9. 
     Makarov, M. and M. Migaud, 2019. Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives. Beilstein J. Org. Chem. 15: 401-430. 
     Rawling JM, Simon MM, Kirkland JB. 1996. Lung poly(ADP-ribose) and NAD+ concentrations during hyperoxia and niacin deficiency in the Fischer-344 rat. Free Radic Biol Med; 20(6):865-71. 
     Studenski SA, Peters KW, Alley DE, Cawthon PM, McLean RR, Harris TB, Ferrucci L, Guralnik JM, Fragala MS, Kenny AM, Kiel DP, Kritchevsky SB, Shardell MD, Dam TT, Vassileva MT (2014). The FNIH sarcopenia project: rationale, study description, conference recommendations, and final estimates. J Gerontol A Biol Sci Med Sci. 69(5), 547-558. 
     Stimpson SA, Leonard MS, Clifton LG, Poole JC, Turner SM, Shearer TW, Remlinger KS, Clark RV, Hellerstein MK, Evans WJ. (2013) Longitudinal changes in total body creatine pool size and skeletal muscle mass using the D&lt;sub&gt;3&lt;/sub&gt;-creatine dilution method. J Cachexia Sarcopenia Muscle. Jun 25. 
     Touat M et al. (2018) DNA repair deficiency sensitizes lung cancer cells to NAD+ biosynthesis blockade. J Clin Invest. Apr 2; 128(4): 1671-1687 
     DESCRIPTION OF FIGURES 
     FIG.  1 . Chemical Structure of Nicotinamide Riboside in its Oxidized (NR) and Reduced (NRH) Forms 
     
         
         1: 1-b-D-ribofuranosyl-3-pyridinecarboxamide salt 
         2: 1,4-dihydro-1-b-D-ribofuranosyl-3-pyridinecarboxamide 
         3: 1,2-dihydro-1-b-D-ribofuranosyl-3-pyridinecarboxamide 
         4: 1,6-dihydro-1-b-D-ribofuranosyl-3-pyridinecarboxamide 
         X - : anion (e.g. triflate) 
       
    
     FIG.  2 . NRH is an Orally Active NAD+ Precursor in Mice 
     8 week-old C57BI/6NTac mice were orally gavaged with either saline (as vehicle), NR (500 mg/kg) or NRH (500 mg/kg). After 1 hour, liver, skeletal muscle and kidney NAD +  levels were evaluated. All results are expressed as mean +/-SEM of n=5 mice per group. * indicates statistical difference at p&lt;0.05 vs. vs. saline-treated mice. # indicates statistical difference at p&lt;0.05 vs. NR treated mice. 
     FIG.  3 . NRH is Found Intact in Mice Tissues After Oral Administration 
     8 week-old C57BI/6NTac mice were orally gavaged with either saline (as vehicle), and NRH (250 mg/kg). After 2 hours, liver, skeletal muscle and kidney NRH levels were evaluated. All results are expressed as mean +/-SEM of n=4 mice per group, as areas under the signal by LC-MS analysis, corrected by total protein amount of tissue. 
     FIG.  4 . NRH is Found Intact in Lung After Oral Administration 
     8 week-old C57BI/6NTac mice were orally gavaged with either saline (as vehicle), and an stable isotope-labelled NRH (250 mg/kg). After 2 hours, NRH levels in the lung were evaluated. All results are expressed as mean +/-SE of n=4 mice per group, as areas under the signal by LC-MS analysis, corrected by total protein amount of tissue. 
     FIG.  5 . NRH Treatment Promotes Anti-bacterial Response Against Salmonella 
     Monocyte-derived macrophages were treated with 0.01 mM NRH for 42 h prior to infection with Salmonella enterica serovar Typhimurium for 1 h using a multiplicity of infection of 10. Following infection, macrophages were treated with gentamicin for 2 h before cell lysis. Values show absolute colony forming unit (CFU) counts with each dot representing one donor and each line representing paired samples. Graphs show pooled data of 2 independent experiments with 2-3 donors/experiment. 
     FIG.  6 . NRH Increases NAD+ in Cultured RAW 264.7 Macrophages 
     RAW 264.7 macrophages were treated with dihydronicotinamide riboside (NRH) at the concentrations indicated. Then, 1 hour later, intracellular NAD+ levels were measured. * indicates p&lt;0.05 vs. Control (0 mM) group. 
     FIG.  7 . NRH Increases NAD+ in Cultured Bone Marrow Derived Macrophages 
     Mouse bone marrow derived macrophages were treated with dihydronicotinamide riboside (NRH) at the concentrations indicated, using PBS as control. Then, 1 or 2 hours later, intracellular NAD+ levels were measured. * indicates p&lt;0.05 vs. Control group. 
     FIG.  8 . NRH Increases NAD +  in Splenocytes 
     Splenocytes were obtained from 1 year old mice and were treated with dihydronicotinamide riboside (NRH) at the concentrations indicated, using PBS as control. Then, 2 hours later, intracellular NAD+ levels were measured. * indicates p&lt;0.05 vs. Control (0 mM) group. 
     EXAMPLES 
     Example 1: Synthesis of the Reduced Form of Nicotinamide Riboside (NRH) 
     Reduced nicotinamide riboside (NRH) was obtained from NR (1) by reduction of pyridinium salts (for example, triflate) to dihydropyridines (1,2-, 1,4-, and 1,6-dihydropyridines) as shown below 
     
       
         
         
             
             
         
       
     
     
         
         1: 1-b-D-ribofuranosyl-3-pyridinecarboxamide salt 
         2: 1,4-dihydro-1-beta-D-ribofuranosyl-3-pyridinecarboxamide 
         3: 1,2-dihydro-1-beta-D-ribofuranosyl-3-pyridinecarboxamide 
         4: 1,6-dihydro-1-beta-D-ribofuranosyl-3-pyridinecarboxamide 
         X - : anion (e.g. triflate) 
       
    
     Sodium borohydride (NaBH 4 ) and sodium dithionite (Na 2 S 2 O 4 ) were used as reducing agents for N-substituted pyridinium derivatives. Regioselectivity of reducing agents differ, leading to either only one dihydropyridine or a mixture of all 3 isomers in different proportions (2,3,4). 
     Dithionate reduction of pyridinium salts, carrying electron withdrawing substituents in positions 3 and 5, yielded almost exclusively 1,4-dihydropyridine products. The reduction was made in mild conditions (e.g. in aqueous sodium bicarbonate or potassium phosphate dibasic medium), due to instability of the reduced products in acidic media. To perform the reduction, hydroxyl groups in the ribofuranose moiety were protected with either benzyl or acetyl substituents. Deprotection was then be done by sodium hydroxide in methanol under ball mill conditions, after reduction. 
     Example 2: Measurement of NRH and Other NAD+ Related Metabolites in Biological Samples 
     Levels of NRH and other NAD-related metabolites in biological samples were obtained by using a cold liquid-liquid extraction using a mixture of methanol:water:chloroform in 5:3:5 (v/v), from which the polar phase was recovered for for hydrophilic interaction ultra-high performance liquid chromatography mass spectrometry (UHPLC-MS) analysis. The UHPLC consisted of a binary pump, a cooled autosampler, and a column oven (DIONEX Ultimate 3000 UHPLC+ Focused, Thermo Scientific), connected to a triple quadrupole spectrometer (TSQ Vantage, Thermo Scientific) equipped with a heated electrospray ionisation (H-ESI) source. Of each sample, 2 µL were injected into the analytical column (2.1 mm × 150 mm, 5 µm pore size, 200 Å HILICON iHILIC®-Fusion(P)), guarded by a pre-column (2.1 mm × 20 mm, 200 Å HILICON iHILIC®-Fusion(P) Guard Kit) operating at 35° C. The mobile phase (10 mM ammonium acetate at pH 9, A, and acetonitrile, B) was pumped at 0.25 mL/min flow rate over a linear gradient of decreasing organic solvent (0.5-16 min, 90-25% B), followed by re-equilibration for a total run time of 30 min. The MS operated in positive mode at 3500 V with multiple reaction monitoring (MRM). The software Xcalibur v4.1.31.9 (Thermo Scientific) was used for instrument control, data acquisition and processing. Retention time and mass detection was confirmed by authentic standards. 
     Structure elucidation of the used NRH for biological studies was confirmed by nuclear magnetic resonance (NMR). 
     Example 3: NRH is Detectable in Circulation After IP Injection 
     NR degradation to NAM has been proposed as a limitation for its pharmacological efficacy. To evaluate whether NRH was also susceptible to degradation to NAM, we spiked NRH or NR in isolated mouse plasma. After 2 h of incubation, NR levels decayed in plasma, in parallel to an increase in NAM. In contrast, NAM was not generated from NRH, as its levels remained stable during the 2 h test. We also tested the stability of NRH in other matrixes. Given our previous experiments in cultured cells, we verified that NRH did not degrade to NAM in FBS supplemented media, as occurs with NR. Finally, we also certified NRH stability in water (pH=7, at room temperature) for 48 h. 
     The above results prompted us to test whether NRH could act as an effective NAD+ precursor in vivo. For this, we first intraperitoneally (IP) injected mice with either NR or NRH (500 mg/kg). After 1 h, both compounds increased NAD+ levels in liver ( FIG.  2   ), muscle and kidney. As expected, NAM levels were highly increased in circulation upon NR administration, while only a very mild increase was observed with NRH. Importantly, NRH was detectable in circulation after IP injection. 
     To our surprise, NR was detectable in circulation after NRH treatment at much higher levels than those detected after NR injection itself. Given that NRH incubation in isolated plasma did not lead to NR production, the appearance of NR might be consequent to intracellular production and release to circulation. Similarly, the residual appearance of NAM after NRH treatment might be explained by the degradation of released NR or by the release of intracellular NAM as a product of NAD+ degradation, as NRH did not significantly alter NAM levels when incubated in isolated plasma. 
     Example 4: NRH is Detectable After Oral Administration as an Orally Bioavailable NAD+ Precursor that Overcomes Direct Degradation in Plasma 
     Oral administration of NRH led to very similar results to those observed after IP administration. First, NRH had a more potent effect on hepatic NAD+ levels than NR. NRH was detectable in plasma 1 h after oral administration. In contrast, NR levels were undetectable at 1 h after NR administration. As expected, NR treatment led to large increases in circulating NAM, which where ~4-fold higher than those observed after NRH treatment. Quantification measurements revealed that after oral gavage, NRH concentration in plasma reached 11.16 ± 1.74 micromolar, which is enough to effectively drive NAD+ synthesis. These results illustrate that NRH is a potent orally bioavailable NAD+ precursor that overcomes direct degradation to NAM in plasma. 
     Example 5: NRH is Found Intact in Liver, Kidney and Muscle After Oral Administration 
     NRH is not only found in circulation but it was also found intact, in high levels, in mice liver, kidney and muscle 2 hours after gavage ( FIG.  3   ). This indicates that oral administration of NRH allows for efficient biodistribution in target tissues. 
     Example 6: NRH is Found in Lung After Oral Administration 
     8 week-old C57BI/6NTac mice were orally gavaged with either saline (as vehicle), and an stable isotope-labelled NRH (250 mg/kg). After 2 hours, NRH levels in the lung were evaluated. All results are expressed as mean +/-SE of n=4 mice per group, as areas under the signal by LC-MS analysis, corrected by total protein amount of tissue ( FIG.  4   ). 
     This indicates that oral administration of NRH allows for efficient biodistribution in the lung. 
     Example 7: NRH Treatment Promotes Anti-bacterial Response Against Salmonella 
     Monocyte-derived macrophages were treated with 0.01 mM NRH for 42 h prior to infection with  Salmonella  enterica serovar Typhimurium for 1 h using a multiplicity of infection of 10. Following infection, macrophages were treated with gentamicin for 2 h before cell lysis. Values show absolute colony forming unit (CFU) counts with each dot representing one donor and each line representing paired samples. Graphs show pooled data of 2 independent experiments with 2-3 donors/experiment. ( FIG.  5   ). 
     Macrophages are critical for protection against infections in the lung (Aegerter 2020) and the killing mechanisms of macrophages are conserved independent of the pathogens. For example, macrophage LC3-associated phagocytosis is critical for protection against Salmonella (gut pathogen- Schulthess 2018) and S. pneumoniae (lung pathogen -Inomata 2020) with similar protective mediators required for Salmonella and M. tuberculosis (lung pathogen) resistance (Serbina 2008). 
     This experiment showed that NRH was able to augment anti-bacterial macrophage response against salmonella. 
     Example 8: NRH Increases NAD+ in Cultured RAW 2647 Macrophages 
     RAW 264.7 macrophages were treated with dihydronicotinamide riboside (NRH) at the concentrations indicated. Then, 1 hour later, intracellular NAD+ levels were measured as described above. Results are presented in  FIG.  6   . 
     This shows that NRH increases NAD+ in cultured RAW 264.7 macrophages. 
     Example 9: NRH Increases NAD+ in Cultured Bone Marrow Derived Macrophages 
     Mouse bone marrow derived macrophages were treated with dihydronicotinamide riboside (NRH) at the concentrations indicated, using PBS as control. Then, 1 or 2 hours later, intracellular NAD+ levels were measured as described above. Results are presented in  FIG.  7   . 
     This shows that NRH increases NAD+ in cultured bone marrow derived macrophages. 
     Example 10: NRH Increases NAD +  in Splenocytes 
     Splenocytes were obtained from 1 year old mice and were treated with dihydronicotinamide riboside (NRH) at the concentrations indicated, using PBS as control. Then, 2 hours later, intracellular NAD+ levels were measured as described above. Results are presented in  FIG.  8   . 
     This shows that NRH increases NAD+ in splenocytes.