Patent Publication Number: US-2022233565-A1

Title: Reduced nicotinamideribosides for treating/preventing skeletal muscle disease

Description:
FIELD OF THE INVENTION 
     The present invention provides compounds and compositions containing reduced nicotinamide riboside for use in methods of prevention and/or treatment of skeletal muscle disease and/or conditions. In one embodiment of the invention, said compounds and compositions of the invention improve skeletal muscle by: maintaining or improving muscle function; maintaining or increasing muscle mass; maintaining or improving muscle strength; and improving muscle recovery and regeneration after injury or surgery. In another embodiment of the invention, compounds and compositions of the invention may be used in methods to prevent and/or treat skeletal muscle diseases and/or conditions such as: cachexia or precachexia; sarcopenia, myopathy, dystrophy, and/or recovery after muscle intense exercise, injury or surgery. 
     BACKGROUND TO THE INVENTION 
     Skeletal muscle regeneration is a crucial mechanism to repair and maintain muscle mass and function throughout life. NAD+ is an plays an important role in skeletal muscle development, regeneration, aging and disease. Lower NAD+ levels are known to be deleterious for muscle health while higher NAD+ levels are known to augment muscle health. 
     On the cellular level, NAD+ influences mitochondrial biogenesis, transcription and organization of extracellular matrix components (Goody, M. F. 2018). In skeletal muscle, NAD+ localization in the mitochondria is important for muscle function with 95% of the NADH in skeletal muscle localized in the mitochondria. 
     Therefore, there is an urgent unmet need to address skeletal muscle disease and/or conditions 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 methods of prevention and/or treatment of skeletal muscle conditions and diseases. 
     In an embodiment, the composition is selected from the group consisting of: a food or beverage product, a food supplement, an oral nutritional supplement (ONS), a medical food, and combinations thereof. 
     In another embodiment, the present invention provides a method for increasing intracellular nicotinamide adenine dinucleotide (NAD + ) in a subject, the method comprising administering a compound or composition of the invention consisting of administering a reduced nicotinamide riboside to the subject in an amount effective to increase NAD biosynthesis. 
     In a further embodiment, as a precursor of NAD+ biosynthesis, reduced nicotinamide riboside, can increase in NAD+ biosynthesis and provide one or more benefits to skeletal muscle function. 
     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 NAD+ biosynthesis. 
     In one embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to maintain or increase skeletal muscle function in a subject. 
     In another embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to maintain or increase skeletal muscle mass in a subject. 
     In yet another embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to prevent or reduce skeletal muscle wasting in a subject. 
     In another embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to enhance recovery of skeletal muscle after intense exercise. 
     In yet another embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to enhance recovery of skeletal muscle after injury. 
     In a further embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to enhance recovery of skeletal muscle after trauma or surgery. 
     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. 
     In another embodiment of the invention, the composition is a nutritional composition containing reduced nicotinamide riboside wherein increased muscle function in muscle is measured by increase in the number of muscle stem cells and/or myoblasts and/or myotubes. 
     In another embodiment of the invention, the composition containing reduced nicotinamide riboside is provided to prevent or treat cachexia or precachexia; sarcopenia, myopathy, dystrophy, and/or recovery after intense exercise, muscle injury or surgery. 
     In a further embodiment of the invention, the composition of the invention containing reduced nicotinamide riboside is provided to be used to prevent or treat cachexia wherein cachexia is associated with a disease selected from cancer, chronic heart failure, renal failure, chronic obstructive pulmonary disease, AIDS, autoimmune disorders, chronic inflammatory disorders, cirrhosis of the liver, anorexia, chronic pancreatitis, metabolic acidosis and/or neurodegenerative disease. 
     In a preferred embodiment of the invention, the nutritional composition of the invention is provided to be used to prevent or treat cachexia or precachexia associated with cancer. 
     In another preferred embodiment of the invention, the nutritional composition of the invention is provided to be used in the treatment of cachexia associated with cancer is selected from pancreas cancer, esophagus, stomach, bowel, lung and/or liver cancer. 
     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 “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). 
     Skeletal Muscle Diseases and Conditions 
     Cachexia and Related Diseases 
     The invention provides compounds, compositions and methods of preventing and/or treating cachexia or skeletal muscle wasting syndrome. Cachexia is a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass. The prominent clinical feature of cachexia is weight loss in adults (corrected for fluid retention) or growth failure in children (excluding endocrine disorders). 
     Cachexia is often seen in patients with diseases such as cancer, chronic heart failure, renal failure, chronic obstructive pulmonary disease, AIDS, autoimmune disorders, chronic inflammatory disorders, cirrhosis of the liver, anorexia, chronic pancreatitis and/or metabolic acidosis and neurodegenerative disease. 
     There are certain types of cancer wherein cachexia is particularly prevalent, for example, pancreas, esophagus, stomach, bowel, lung and/or liver cancer. 
     The internationally recognised diagnostic criterion for cachexia is weight loss greater than 5% over a restricted time, for example 6 months, or weight loss greater than 2% in individuals already showing depletion according to current body weight and height (body-mass index [BMI] &lt;20 kg/m 2 ) or skeletal muscle mass (measured by DXA, MRI, CT or bioimpedance). Cachexia can develop progressively through various stages—precachexia to cachexia to refractory cachexia. Severity can be classified according to degree of depletion of energy stores and body protein (BMI) in combination with degree of ongoing weight loss. 
     In particular, cancer cachexia has been defined as weight loss &gt;5% over past 6 months (in absence of simple starvation); or BMI&lt;20 and any degree of weight loss &gt;2%; or appendicular lean mass consistent with low muscle mass (males &lt;7.26 kg/m 2 ; females &lt;5.45 kg/m 2 ) and any degree of weight loss &gt;2% (Fearon et al. 2011). 
     Precachexia may be defined as weight loss ≤5% together with anorexia and metabolic change. At present there are no robust biomarkers to identify those precachectic patients who are likely to progress further or the rate at which they will do so. Refractory cachexia is defined essentially on the basis of the patient&#39;s clinical characteristics and circumstances. 
     It may be appreciated that the compounds, compositions and methods of the present invention may be beneficial for the prevention and/or treatment of the condition of precachexia as well as cachexia in particular to maintain or improve skeletal muscle mass and/or muscle function. 
     In one embodiment of the invention, the invention provides a method of treatment of cachexia or precachexia comprising administering to a human or animal subject an effective amount of a compound of the invention. 
     In another embodiment of the invention, the invention provides a method of treatment of cachexia or precachexia comprising administering to a human or animal subject an effective amount of a compound of the invention wherein cachexia or precachexia is associated with a disease selected from cancer, chronic heart failure, renal failure, chronic obstructive pulmonary disease, AIDS, autoimmune disorders, chronic inflammatory disorders, cirrhosis of the liver, anorexia, chronic pancreatitis, metabolic acidosis and/or neurodegenerative disease. 
     In a preferred embodiment of the invention, the invention provides a method of treatment of cancer cachexia is associated with cancer is selected from pancreas, esophagus, stomach, bowel, lung and/or liver cancer. 
     In yet another embodiment of the invention, the invention provides a method of treatment wherein treatment of cancer cachexia is measured by reducing body weight loss, preventing body weight loss, maintaining body weight or increasing body weight. 
     In another embodiment of the invention, a compound or a composition of the invention may be used in a method of treatment wherein cancer cachexia is a result of treatment for cancer with a chemotherapeutic agent. 
     In a further embodiment of the invention, a compound or a composition of the invention may be used in a method of prevention or treatment of cachexia in combination with a dietary intervention of high caloric, high protein, high carbohydrate, Vitamin B3, Vitamin B12 and/or Vitamin D supplementation, antioxidants, omega fatty acids, and/or polyphenols. 
     Sarcopenia and Related Diseases 
     Sarcopenia can be characterized by one or more of low muscle mass, low muscle strength and low physical performance. 
     Sarcopenia can be diagnosed in a subject based on the definition of the AWGSOP (Asian Working Group for Sarcopenia in Older People), for example as described in Chen et al., 2014. Low muscle mass can generally be based on low appendicular lean mass normalized to height square (ALM index), particularly ALM index less than 7.00 kg/m2 for men and 5.40 kg/m2 for women. Low physical performance can generally be based on gait speed, particularly gait speed of &lt;0.8 m/sec. Low muscle strength can generally be based on low hand grip strength, particularly hand grip strength less than 26 kg in men and less than 18 kg in women. 
     Sarcopenia can be diagnosed in a subject based on the definition of the EWGSOP (European Working Group for Sarcopenia in Older People), for example as described in Crutz-Jentoft et al., 2010. Low muscle mass can generally be based on low appendicular lean mass normalized to height square (ALM index), particularly ALM index less than 7.23 kg/m2 for men and 5.67 kg/m2 for women. Low physical performance can generally be based on gait speed, particularly gait speed of &lt;0.8 m/sec. Low muscle strength can generally be based on low hand grip strength, particularly hand grip strength less than 30 kg in men and less than 20 kg in women. 
     Sarcopenia can be diagnosed in a subject based on the definition of the Foundation for the National Institutes of Health (FNIH), for example as described in Studenski et al., 2014. Low muscle mass can generally be based on low appendicular lean mass (ALM) normalized to body mass index (BMI; kg/m2), particularly ALM to BMI less than 0.789 for men and 0.512 for women. Low physical performance can generally be based on gait speed, particularly gait speed of &lt;0.8 m/sec. Low muscle strength can generally be based on low hand grip strength, particularly hand grip strength less than 26 kg in men and less than 16 kg in women. Low muscle strength can also generally be based on low hand grip strength to body mass index, particularly hand grip strength to body mass index less than 1.00 in men and less than 0.56 in women. 
     The D3-creatine dilution method is another approach to measure muscle mass. This method is becoming more widely accepted as a robust standard and potentially a future alternative to DXA. The D3-creatine dilution method has been described previously in Clark et al. (1985) and Stimpson et al. (2013). 
     It may be appreciated that the compounds, compositions and methods of the present invention may be beneficial to prevent and/or treat sarcopenia and/or related conditions, in particular, to maintain or improve skeletal muscle mass and/or muscle function. 
     Myopathy and Related Conditions 
     Myopathies are neuromuscular disorders in which the primary symptom is muscle weakness due to dysfunction of muscle fiber. Other symptoms of myopathy can include include muscle cramps, stiffness, and spasm. Myopathies can be inherited (such as the muscular dystrophies) or acquired (such as common muscle cramps). 
     Myopathies are grouped as follows: (i) congenital myopathies: characterized by developmental delays in motor skills; skeletal and facial abnormalities are occasionally evident at birth (ii) muscular dystrophies: characterized by progressive weakness in voluntary muscles; sometimes evident at birth (iii) mitochondrial myopathies: caused by genetic abnormalities in mitochondria, cellular structures that control energy; include Kearns-Sayre syndrome, MELAS and MERRF glycogen storage diseases of muscle: caused by mutations in genes controlling enzymes that metabolize glycogen and glucose (blood sugar); include Pompe&#39;s, Andersen&#39;s and Con&#39;s diseases (iv) myoglobinurias: caused by disorders in the metabolism of a fuel (myoglobin) necessary for muscle work; include McArdle, Tarui, and DiMauro diseases (v) dermatomyositis: an inflammatory myopathy of skin and muscle (vi) myositis ossificans: characterized by bone growing in muscle tissue (vii) familial periodic paralysis: characterized by episodes of weakness in the arms and legs (viii)polymyositis, inclusion body myositis, and related myopathies: inflammatory myopathies of skeletal muscle (ix) neuromyotonia: characterized by alternating episodes of twitching and stiffness; and stiff-man syndrome: characterized by episodes of rigidity and reflex spasms common muscle cramps and stiffness, and (x) tetany: characterized by prolonged spasms of the arms and legs. (Reference: https://www.ninds.nih.gov/disorders/all-disorders/myopathy-information-page). 
     It may be appreciated that the compounds, compositions and methods of the present invention may be beneficial to prevent and/or treat the aforementioned diseases or conditions, in particular, to maintain or improve skeletal muscle mass and/or muscle function. 
     Muscular Dystrophy 
     Muscular dystrophy are a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal or voluntary muscles which control movement. Major types of muscular dystrophy include: Duchenne muscular dystrophy, Becker muscular dystrophy, limb-girdle muscular dystrophy, facioscapulohumeral muscular dystrophy, congenital muscular dystrophy, oculopharyngeal muscular dystrophy, distal muscular dystrophy, Emery-Dreifuss muscular dystrophy and myotonic dystrophy. 
     (Reference: https://www.medicalnewstoday.com/articles/187618.php) 
     It may be appreciated that the compounds, compositions and methods of the present invention may be beneficial to prevent and/or treat the aforementioned diseases or conditions, in particular, to maintain or improve skeletal muscle mass and/or muscle function, 
     Recovery after Muscle Injury from Surgery and Muscle Traumas 
     Muscle injuries can be caused by bruising, stretching or laceration causing acute or chronic soft tissue injury that occurs to a muscle, tendon, or both. It may occur as a result of fatigue, overuse, or improper use of a muscle, for example, during intense exercise. It may occur after physical trauma such as a fall, fracture or overuse during physical activity. Muscle injuries may also occur after surgery such as joint replacement arthroscopic surgery. 
     It may be appreciated that the compounds, compositions and methods of the present invention may be beneficial to prevent and/or treat the aforementioned conditions of recovery after surgery and/or muscle trauma, in particular, to maintain or improve skeletal muscle mass and/or muscle function. 
     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 intracellular NAD in subject in need thereof. 
     The increase in NAD biosynthesis 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 prevention or treatment of skeletal muscle disease. 
     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. 
     Another aspect of the present invention is a method for increasing intracellular NAD in a mammal in need thereof, comprising administering to the mammal a composition consisting essentially of or consisting of reduced nicotinamide riboside in an amount effective to increase NAD +  biosynthesis. The method can promote the increase of intracellular levels of NAD in cells and tissues for improving cell and tissue survival and overall cell and tissue health, for example, in muscle cells and tissues, especially skeletal muscle cells and tissues. 
     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). 
     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 present invention, discloses a new molecule that can act as an extracellular NAD+ precursor, reduced nicotinomide riboside (NRH). 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. 
     The present invention relates to NRH, a new molecule which can act as an NAD+ precursor. This reduced form of NR, which displays an unprecedented ability to increase NAD+ and has the advantage of being more potent and faster than nicotinamide riboside (NR). NRH utilizes a different pathway than NR to synthesize NAD+, which is NRK independent. 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 method comprises administering an effective amount of a composition consisting essentially of reduced nicotinamide riboside or consisting of reduced nicotinamide riboside to the individual. 
     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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       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 . Dose-response experiments revealed that NRH could significantly increase NAD+ better than NR   
       Starting at levels at a concentration of 10 μM, NRH achieved similar increases in intracellular NAD+ levels to those reached with NR at 50-fold higher concentrations. NRH achieved maximal effects on NAD+ synthesis around the millimolar range, managing to increase intracellular NAD+ levels by more than 10-fold. 
         FIG. 3 . NHR acts rapidly after 5 minutes from treatment. 
       NRH actions were also extremely fast, as significant increases in NAD+ levels were observed within 5 minutes after NRH treatment. Peak levels of NAD+ were achieved between 45 minutes and 1 h after treatment. 
         FIG. 4 . NRH leads to NAD+ biosynthesis through an adenosine kinase dependent path. AML12 cells were treated with an adenosine kinase inhibitor (5-IT; 10 mM) for 1 hour prior to NRH treatment at the doses indicated. Then, 1 hour later, acidic extracts were obtained to measure NAD +  levels. All values in the figure are expressed as mean+/−SEM of 3 independent experiments. * indicates statistical difference at p&lt;0.05 vs. the respective vehicle treated group. 
         FIG. 5 . 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. 6 . NRH is found intact in mice tissues after 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. 
     
    
    
     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 a Potent NAD+ Precursor 
     AML12 hepatocytes were treated with NRH, and it was observed that the ability of NRH to increase intracellular NAD+ was superior to that of NR. 
     Dose-response experiments revealed that NRH could significantly increase NAD+ levels at a concentration of 10 μM ( FIG. 2 ). Even at such relatively low dose, NRH achieved similar increases in intracellular NAD+ levels to those reached with NR at 50-fold higher concentrations. NRH achieved maximal effects on NAD+ synthesis around the millimolar range, managing to increase intracellular NAD+ levels by more than 10-fold. 
     NRH actions were also extremely fast ( FIG. 3 ), as significant increases in NAD+ levels were observed within 5 minutes after NRH treatment. Peak levels of NAD+ were achieved between 45 minutes and 1 h after treatment, as also occurred with NR. 
     The ability of NRH to potently increase NAD+ was tested as well in other cell type models. NRH treatment highly elevated NAD+ levels in C2C12 myotubes, INS1-cells and 3T3 fibroblasts, supporting the notion that NRH metabolism is widely conserved among different cell types. 
     Example 4: Pathway of NRH-Induced NAD+ Synthesis 
     A path in which NRH would be converted to NMNH, then to NADH and this would be finally oxidized to NAD+. Accordingly, NRH and NMNH could be detected intracellularly 5 minutes after NRH, but not NR, treatment. Interestingly, NRH treatment also led to an increase in intracellular NR and NMN, greater than that triggered by NR itself, opening the possibility that NRH could synthesize NAD+ by being oxidized to NR, using then the canonical NRK/NMNAT path. 
     In order to understand the exact path by which NRH synthesizes NAD+, we initially evaluated whether NRH, could be transported into the cell by equilibrative nucleoside transporters (ENTs). Confirming this possibility, NRH largely lost its capacity as an extracellular NAD+ precursor in the presence of an agent blocking ENT-mediated transport, such as S-(4-nitrobenzyl)-6-thioinosine (NBTI). Nevertheless, a substantial action of NRH remained even after ENT blockage, suggesting that NRH might be able to enter the cell through additional transporters. 
     The action of NRH was also NAMPT-independent, based on experiments using FK866, a NAMPT inhibitor. If NRH led to NAD+ synthesis via the formation of NMNH, this hypothetical path would require the phosphorylation of NRH into NMNH. Given the essential and rate-limiting role of NRK1 in NR phosphorylation, we wondered whether the ability of NRH to boost NAD+ levels was NRK1 dependent. To answer this question, we evaluated NRH action in primary hepatocytes from either control or NRK1 knockout (NRK1KO) mice. While after 1 hour of treatment NR failed to increase NAD+ levels in NRK1KO derived primary hepatocytes, NRH action was not affected by NRK1 deficiency. These results indicate that NRH action is NRK1 independent. Further, they rule out the possibility that NRH-induced NAD+ transport is driven by NRH oxidation into NR. 
     Considering the molecular structure of NRH, we reasoned that an alternative nucleoside kinase could be responsible for the phosphorylation of NRH. Confirming this expectation, the adenosine kinase (AK) inhibitor 5-iodotubercidin (5-IT) fully ablated the action of NRH. The role of AK in NRH-mediated NAD+ synthesis was confirmed using a second, structurally different, AK inhibitor, ABT-702. Metabolomic analyses further confirmed that upon inhibition of AK, the generation of NMNH, NADH and NAD+ was fully blunted, even if NRH was effectively entering the cell. Interestingly, 5-IT treatment also prevented the formation of NR and NMN after NRH treatment. 
     This indicates that the occurrence of NR after NRH treatment cannot be attributed simply to direct NRH intracellular oxidation to NR. As a whole, these experiments depict adenosine kinase as the enzymatic activity catalyzing the conversion of NRH into NMNH, initiating this way the transformation into NAD+. 
     As a follow-up step, NMNAT enzymes could catalyze the transition from NMNH to NADH. Accordingly, the use of gallotannin as a NMNAT inhibitor largely compromised NAD+ synthesis after NRH treatment. Yet, part of the NRH action remained after gallotannin treatment when NRH was used at maximal doses. However, NRH action was totally blocked by gallotannin at submaximal doses, suggesting that the remaining effect at 0.5 mM could be attributed to incomplete inhibition of NMNAT activity by gallotannin. Altogether, these results indicate that adenosine kinase and NMNATs vertebrate the path by which NRH leads to NAD+ synthesis via NADH. 
     Example 5: 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. 5 ), 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 6: 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 7: 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. 6 ). This indicates that oral administration of NRH allows for efficient biodistribution in target tissues.