Niacin Cures Systemic NAD+ Deficiency and Improves Muscle Performance in Adult-Onset Mitochondrial Myopathy
Authors: Vidya Velagapudi
Juho Kuula
Marja-Riitta Taskinen
Alberto Pessia
Kirsi H Pietiläinen
Nina Lundbom
Antti Hakkarainen
Ulla Heinonen
Mari Auranen
Charles Brenner
Niina Urho
Päivi Piirilä
Kimmo Haimilahti
Mark S Schmidt
Eija Pirinen
Virginia Brilhante
Nahid A Khan
Anu Suomalainen
Journal: Cell Metabolism (2020)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: NAD(+); NAD(+) repletion; mitochondria; mitochondrial disease; mitochondrial myopathy
Affiliations: Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland. Electronic address: ., Research Program of Stem Cells and Metabolism, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland; Department of Neurosciences, Helsinki University Hospital, Helsinki, Finland., Research Program of Stem Cells and Metabolism, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland., Department of Neurosciences, Helsinki University Hospital, Helsinki, Finland., Metabolomics Unit, Institute for Molecular Medicine Finland (FIMM), Helsinki 00290, Finland., Department of Radiology, Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo 12200, Finland., Department of Radiology, Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland., Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA., Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland., Unit of Clinical Physiology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland., Obesity Research Unit, Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland; Obesity Centre, Abdominal Centre, Endocrinology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland., Research Program of Stem Cells and Metabolism, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland; HUSlab, Helsinki University Hospital, Helsinki 00290, Finland; Neuroscience Center, HiLife, University of Helsinki, Helsinki 00290, Finland. Electronic address: .

Abstract:  NAD+ is a redox-active metabolite, the depletion of which has been proposed to promote aging and degenerative diseases in rodents. However, whether NAD+ depletion occurs in patients with degenerative disorders and whether NAD+ repletion improves their symptoms has remained open. Here, we report systemic NAD+ deficiency in adult-onset mitochondrial myopathy patients. We administered an increasing dose of NAD+-booster niacin, a vitamin B3 form (to 750-1,000 mg/day; clinicaltrials.govNCT03973203) for patients and their matched controls for 10 or 4 months, respectively. Blood NAD+ increased in all subjects, up to 8-fold, and muscle NAD+ of patients reached the level of their controls. Some patients showed anemia tendency, while muscle strength and mitochondrial biogenesis increased in all subjects. In patients, muscle metabolome shifted toward controls and liver fat decreased even 50%. Our evidence indicates that blood analysis is useful in identifying NAD+ deficiency and points niacin to be an efficient NAD+ booster for treating mitochondrial myopathy. 

Retracted: No

PubPeer comments:
 This important study aims to translate NAD precursor-based therapies from animal models to patients. I am just wondering the ubiquitous use of u201cfold changesu201d in the figures. Considering the nature of the study design and the small number of cases, why not to present all data as done in the Supplementary Figure 6A-F and allow each patient to serve his her own control? For example, compare Figure 3A and Supplementary Figure 6A. ![file] Compare also data in Figure 3C, and Supplementary Figure 6C, and the following statement: u201cAfter 10 months of niacin, patients showed improved muscle strength, differentially in different muscle groups: on the average 10-fold in abdominal musclesu2026u201d ![file] Moreover, Figures 3D-F appear to show misuse of statistics. How come 5 patients yield 10 data points? It seems that the data points derive from left and right hand. Such data points are not independent as two data points come from the same individual. Therefore, the applied statistics is not valid (or more clarification is needed). Neither should such data points be used to describe a data distribution (box blot)u2026. ![file] Nonetheless, some biochemical parameters do suggest a promising effect by niacin but, in my opinion, the title is a rather bold statement from an uncontrolled follow-up of 5 patients with minimal effect sizesu2026 , 
 By a quick look, the same issues caught my attention as Agabus Ajax s: small number of patients, small effects and somewhat misleading presentation of the data. When I clicked on the ClinicalTrials.gov link to check what outcome parameters they had listed, I noticed that, strangely, the project seemed to have been posted well after it was performed. I don t know if this is acceptable or not, but together with the issues above it certainly makes this seem like it was not planned to be a real clinical trial in the first place. First Submitted Date ICMJEtMay 24, 2019 Actual Study Start Date ICMJEtJune 1, 2014 Actual Primary Completion DatetDecember 31, 2017 (Final data collection date for primary outcome measure) , 
 By a bit longer look, e.g. at the reference list of this paper, several of the authors have been involved in studies of nicotinamide riboside (NR), a natural niacin derivative that can likewise be metabolized to NAD+, but does not bind the niacin hydroxycarboxylic acid receptor 2 (HCAR2 GPR109A), which is mainly expressed in WAT and macrophages. In the current study, the authors have, for reasons they donu2019t clarify, used niacin (used widely as lipid-lowering drug with brand names such as Niacor and Niaspan) instead or NR. Despite this, they omit discussing the well-known effects of niacin on lipid mobilization and utilization, as well as its anti-inflammatory effects, mediated by HCAR2. They even cite papers (Plaisance et al., 2009; Westphal et al., 2007) describing these HCAR2-mediated effects (like hepatic fat accumulation and adiponectin level), but they still attribute the effects they observed in their patients solely to NAD+ metabolism. This seems a very odd choice, to say the least, particularly as the authors report blood lipid data (Supplementary). Pirinen et al. Results: u201cWe found the biologically active high molecular weight form of adiponectin to be robustly increased in plasma in all niacin-treated subjects (Figure 2H) and to correlate negatively with liver fat content (Figure 2I). These results suggest that NAD+ contributes to adiponectin signaling, the activation of which could explain the effects of niacin on liver fat content in mitochondrial disease patients.u201d On another note, acipimox, a niacin analog and HCAR2 GPR109A agonist (also in clinical use), which cannot(*) be metabolized to NAD+ because of its pyrazine ring, has been reported to improve skeletal muscle mitochondrial function (see references below). Itu2019s hard to understand why the reviewers for a journal like Cell Metabolism, which has a strong emphasis on molecular mechanisms, apparently didnu2019t require discussion of these aspects in the context of a clinical trial, as the HCAR2-mediated effects may be highly clinically relevant in mitochondrial myopathy. Dollerup OL, Chubanava S, Agerholm M, et al. Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men. J Physiol. 2020;598(4):731u2010754. doi:10.1113 JP278752 Daniele G, Eldor R, Merovci A, Clarke GD, Xiong J, Tripathy D, Taranova A, Abdul-Ghani M DeFronzo RA (2014). Chronic reduction of plasma free fatty acid improves mitochondrial function and whole-body insulin sensitivity in obese and type 2 diabetic individuals. Diabetes 63, 2812u20132820 van de Weijer T, Phielix E, Bilet L, Williams EG, Ropelle ER, Bierwagen A, Livingstone R, Nowotny P, Sparks LM, Paglialunga S, Szendroedi J, Havekes B, Moullan N, Pirinen E, Hwang JH, Schrauwen-Hinderling VB, Hesselink MK, Auwerx J, Roden M Schrauwen P (2015). Evidence for a direct effect of the NAD+ precursor acipimox on muscle mitochondrial function in humans. Diabetes 64, 1193u20131201. (*) Despite so claimed by van de Weijer et al. Diabetes (2015). See my earlier post about this issue here: https: pubpeer.com publications 0E01B2787A2C36DF592DC3B0AF2CAE , 
 #1 Given that baseline performance and other parameters markedly differed between the patients due the different disease severity state, we chose to present the data as a fold change compared to baseline to understand better the response to niacin. In this case, each patient served also as her his own control and the fold change was calculated by dividing each patientu2019s post niacin values with his her own baseline values. We agree that the improvement in abdominal muscle strength was largely attributable to results of one patient. Of note, this was the weakest patients at baseline. Regarding the other parameters, niacin-induced improvements were observed in most of the patients as can been seen in Supplemental Figure 6 in the manuscript. As described in the y axis, data for repetitive shoulder muscle lift, elbow flexion and knee extension are combined from left and right sides. This approach is not actually uncommon in the field of muscle diseases and sport science. Alternative approaches, separate analysis of one limb, the most dominant side or the side with the most clinically evident symptoms of disease, may also result in a loss of valuable data and may introduce a bias through the choice of which limb to use. We decided to pool the data as it did not basically change our results. As can be seen below, when data was analyzed separately for one side, improvements in muscle strength can be still observed and particularly on the left side. ![file] , 
 #2 The trial was not initially preregistered at the time when the trial was started (2014-2015). This was solely for the reason that ethical guidelines in Finland required the study to fill strict ethical guidelines of European Union, and approval of the trial by hospital ethical review board (Helsinki University Hospital). The authority found to study to fully fill the requirements of good research practice, and without passing this authority no clinical trials can be performed in our country. However, at the time, the ethical guidelines of the country did not require or ask for registration of open-label non-randomized studies in international registries. , 
 #3 In current study we chose to exploit niacin as it has a proven safety profile in humans from the past 50 years, when used for a lowering drug for hypercholesterolemia. At the time when the trial was started, NR was not available pure enough for human studies, and even today, no studies of the safety of NR have been published in mitochondrial patients. Despite the long use of niacin for dyslipidemia, all mechanism of actions of niacin are not clear. However, the current evidence in literature points to the NAD+ sirtuin-axis as one of the key mediators of niacinu2019s health benefits. See for example review Mario et al J Lipid Res 2019 Apr;60(4):741-746. We agree that niacin induced increase in adiponectin levels likely also requires GPR109A receptor as niacin administration did not increase adiponectin levels in the GPR109A receptor knockout mice. Of note, there are studies showing that sirtuin 1 activation also increases circulating adiponectin levels (see review Jokinen et al Redox Biology 12 (2017) 246u2013263). The role of GPR109A receptor as a mediator of niacinu2019s anti-hyperlipidemic effect has also been challenged. See for example by Lauring et al Sci Transl Med 2012 Aug 22;4(148):148ra115. However, we cannot exclude the possibility that some of the beneficial alterations observed in our study were mediated via the GPR109A receptor. Overall, we propose that NAD+ sirtuin-axis play an important role in the mechanism of action of niacin. We show that niacin remarkably increases NAD+ amount in circulation and improves it also in the muscle u2013 and this endpoint is also the goal of other NAD+ boosters. ,