1.
The NADPARK study: A randomized phase I trial of nicotinamide riboside supplementation in Parkinson's disease.
Brakedal, B, Dölle, C, Riemer, F, Ma, Y, Nido, GS, Skeie, GO, Craven, AR, Schwarzlmüller, T, Brekke, N, Diab, J, et al
Cell metabolism. 2022;34(3):396-407.e6
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Parkinson’s disease (PD) is a major cause of death and disability, and current treatments can provide partial symptomatic relief, mainly for motor symptoms but make no substantial impact on disease progression. A growing body of evidence supports that boosting cellular levels of nicotinamide adenine dinucleotide (NAD) may confer neuroprotective effects in both healthy aging and neurodegeneration. The primary aim of this study was to assess penetration and metabolic responses of the brain to nicotinamide riboside (NR) supplementation in patients with PD. This study is a double-blinded, randomised, placebo-controlled phase I study of NR in newly diagnosed PD patients, naïve to dopaminergic therapy. Participants (n=30) where randomly assigned (1:1) to one of the two groups: NR group or placebo group. Results show that: - oral NR therapy increases brain NAD levels and impacts cerebral metabolism in PD. - supplementation with NR may target multiple processes implicated in the pathophysiology of the disease by upregulating the expression of genes involved in mitochondrial respiration, oxidative damage response, lysosomal and proteasomal function and downregulating inflammatory cytokines in the central nervous system. Authors conclude that NR can be a potential neuroprotective agent against PD. However, further investigation in a larger trial is required to warrant these findings.
Abstract
We conducted a double-blinded phase I clinical trial to establish whether nicotinamide adenine dinucleotide (NAD) replenishment therapy, via oral intake of nicotinamide riboside (NR), is safe, augments cerebral NAD levels, and impacts cerebral metabolism in Parkinson's disease (PD). Thirty newly diagnosed, treatment-naive patients received 1,000 mg NR or placebo for 30 days. NR treatment was well tolerated and led to a significant, but variable, increase in cerebral NAD levels-measured by 31phosphorous magnetic resonance spectroscopy-and related metabolites in the cerebrospinal fluid. NR recipients showing increased brain NAD levels exhibited altered cerebral metabolism, measured by 18fluoro-deoxyglucose positron emission tomography, and this was associated with mild clinical improvement. NR augmented the NAD metabolome and induced transcriptional upregulation of processes related to mitochondrial, lysosomal, and proteasomal function in blood cells and/or skeletal muscle. Furthermore, NR decreased the levels of inflammatory cytokines in serum and cerebrospinal fluid. Our findings nominate NR as a potential neuroprotective therapy for PD, warranting further investigation in larger trials.
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Metabolic stress-dependent regulation of the mitochondrial biogenic molecular response to high-intensity exercise in human skeletal muscle.
Fiorenza, M, Gunnarsson, TP, Hostrup, M, Iaia, FM, Schena, F, Pilegaard, H, Bangsbo, J
The Journal of physiology. 2018;596(14):2823-2840
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Endurance exercise stimulates mitochondrial biogenesis in skeletal muscles, a crucial adaptive protective mechanism against various metabolic disorders. Mitochondrial biogenesis is a process that involves the expansion of mitochondrial volume and changes in mitochondrial composition. Continuous moderate‐intensity exercise (CM) may lead to mild but prolonged metabolic disturbances, and low‐volume intense intermittent exercise regimes such as repeated‐sprint (RE) and speed endurance (SE) exercises may lead to a distinct degree of metabolic stress. This randomised counter-balanced crossover trial included 12 healthy trained men to investigate the effect of RE and SE exercise and high‐volume CM on metabolic perturbations and its impact on the regulation of molecular response stimulating mitochondrial biogenesis in human skeletal muscle. Compared to CM, PGC‐1α mRNA (Peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α) mRNA) showed elevation in response to RS and SE exercises in well-trained subjects, and this was associated with high accumulation of muscle lactate, greater decline in muscle pH and elevated plasma adrenaline levels. Elevated metabolic perturbations lead to enhanced mitochondrial biogenesis-related mRNA responses. SE was associated with a greater increase in the PGC‐1α mRNA and severe metabolic stress. SE and CM elevated exercise-induced signalling and mRNA content of genes controlling mtDNA. Further robust research is required to elucidate the role of metabolic stress in initiating mitochondrial biogenesis in skeletal muscles in response to acute exercise, regulating genes modulating mtDNA transcription and mitochondrial remodelling dynamics. However, healthcare professionals can use the results of this study to understand that low-volume high-intensity exercise programmes can promote mitochondrial biogenesis in skeletal muscles in healthy trained men and have a similar effect to that of high-volume moderate-intensity exercise programmes.
Abstract
KEY POINTS Low-volume high-intensity exercise training promotes muscle mitochondrial adaptations that resemble those associated with high-volume moderate-intensity exercise training. These training-induced mitochondrial adaptations stem from the cumulative effects of transient transcriptional responses to each acute exercise bout. However, whether metabolic stress is a key mediator of the acute molecular responses to high-intensity exercise is still incompletely understood. Here we show that, by comparing different work-matched low-volume high-intensity exercise protocols, more marked metabolic perturbations were associated with enhanced mitochondrial biogenesis-related muscle mRNA responses. Furthermore, when compared with high-volume moderate-intensity exercise, only the low-volume high-intensity exercise eliciting severe metabolic stress compensated for reduced exercise volume in the induction of mitochondrial biogenic mRNA responses. The present results, besides improving our understanding of the mechanisms mediating exercise-induced mitochondrial biogenesis, may have implications for applied and clinical research that adopts exercise as a means to increase muscle mitochondrial content and function in healthy or diseased individuals. ABSTRACT The aim of the present study was to examine the impact of exercise-induced metabolic stress on regulation of the molecular responses promoting skeletal muscle mitochondrial biogenesis. Twelve endurance-trained men performed three cycling exercise protocols characterized by different metabolic profiles in a randomized, counter-balanced order. Specifically, two work-matched low-volume supramaximal-intensity intermittent regimes, consisting of repeated-sprint (RS) and speed endurance (SE) exercise, were employed and compared with a high-volume continuous moderate-intensity exercise (CM) protocol. Vastus lateralis muscle samples were obtained before, immediately after, and 3 h after exercise. SE produced the most marked metabolic perturbations as evidenced by the greatest changes in muscle lactate and pH, concomitantly with higher post-exercise plasma adrenaline levels in comparison with RS and CM. Exercise-induced phosphorylation of CaMKII and p38 MAPK was greater in SE than in RS and CM. The exercise-induced PGC-1α mRNA response was higher in SE and CM than in RS, with no difference between SE and CM. Muscle NRF-2, TFAM, MFN2, DRP1 and SOD2 mRNA content was elevated to the same extent by SE and CM, while RS had no effect on these mRNAs. The exercise-induced HSP72 mRNA response was larger in SE than in RS and CM. Thus, the present results suggest that, for a given exercise volume, the initial events associated with mitochondrial biogenesis are modulated by metabolic stress. In addition, high-intensity exercise seems to compensate for reduced exercise volume in the induction of mitochondrial biogenic molecular responses only when the intense exercise elicits marked metabolic perturbations.
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Cognitive impairment in coeliac disease improves on a gluten-free diet and correlates with histological and serological indices of disease severity.
Lichtwark, IT, Newnham, ED, Robinson, SR, Shepherd, SJ, Hosking, P, Gibson, PR, Yelland, GW
Alimentary pharmacology & therapeutics. 2014;40(2):160-70
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Coeliac disease (CD) is an inflammatory autoimmune disorder caused by the ingestion of gluten. While CD is known to primarily affect the bowel, there is reported evidence of potential neurological side effects. Cognition may be impaired in undiagnosed CD patients because of nutrient deficiencies, systemic inflammation and changes in the gut microbiome. CD patients often report a mild cognitive impairment, brain fog, characterised by difficulty concentrating, short-term memory and confusion. The aim of this study was to investigate the relationship between gut mucosal healing and cognitive function in eleven patients recently diagnosed with CD commencing a strict gluten-free diet. The findings of this study showed that in newly diagnosed CD patients, cognitive functioning improved with a gluten-free diet and was correlated with mucosal healing. Based on this study, the authors conclude that cognition is impaired in people with untreated coeliac disease and may affect the performance of everyday tasks. This finding also introduces the possibility of using cognitive tests to provide a marker of intestinal healing.
Abstract
BACKGROUND Mild impairments of cognition or 'Brain fog' are often reported by patients with coeliac disease but the nature of these impairments has not been systematically investigated. AIM: This longitudinal pilot study investigated relationships between cognitive function and mucosal healing in people with newly diagnosed coeliac disease commencing a gluten-free diet. METHODS Eleven patients (8 females, 3 males), mean age 30 (range 22-39) years, were tested with a battery of cognitive tests at weeks 0, 12 and 52. Information processing efficacy, memory, visuospatial ability, motoric function and attention were tested. Small bowel biopsies were collected via routine gastroscopy at weeks 12 and 52 and were compared to baseline Marsh scores. Cognitive performance was compared to serum concentrations of tissue transglutaminase antibodies, biopsy outcomes and other biological markers. RESULTS All patients had excellent adherence to the diet. Marsh scores improved significantly (P = 0.001, Friedman's test) and tissue transglutaminase antibody concentrations decreased from a mean of 58.4 at baseline to 16.8 U/mL at week 52 (P = 0.025). Four of the cognitive tests assessing verbal fluency, attention and motoric function showed significant improvement over the 12 months and strongly correlated with the Marsh scores and tissue transglutaminase antibody levels (r = 0.377-0.735; all P < 0.05). However, no meaningful patterns of correlations were found for nutritional or biochemical markers, or markers of intestinal permeability. CONCLUSIONS In newly diagnosed coeliac disease, cognitive performance improves with adherence to the gluten-free diet in parallel to mucosal healing. Suboptimal levels of cognition in untreated coeliac disease may affect the performance of everyday tasks.