1.
Protective effect of probiotics in patients with non-alcoholic fatty liver disease.
Cai, GS, Su, H, Zhang, J
Medicine. 2020;99(32):e21464
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Plain language summary
Non-alcoholic fatty liver disease (NAFLD) is common in people with obesity and is characterised by high amounts of fat stored in the liver. Diet and exercise are the standard treatments, however recent studies have indicated that the gut microbiota may have an important role. This randomised control trial of 140 patients with NAFLD, aimed to assess the effect of probiotics when added to standard therapy for 3 months. The results showed that although gut microbiota, some aspects of liver function, blood lipids and blood sugars were all improved in individuals on standard therapy, there were additional improvements in those on standard therapy plus probiotics. It was concluded that although standard therapy alone is adequate to improve NAFLD, probiotics plus standard therapy was superior to standard therapy alone and effective in treatment of NAFLD. This study could be used by health professionals to justify the addition of probiotics to standard therapy to further improve NAFLD outcomes.
Abstract
To investigate the effects of probiotics on liver function, glucose and lipids metabolism, and hepatic fatty deposition in patients with non-alcoholic fatty liver disease (NAFLD).Totally 140 NAFLD cases diagnosed in our hospital from March 2017 to March 2019 were randomly divided into the observation group and control group, 70 cases in each. The control group received the diet and exercise therapy, while the observation group received oral probiotics based on the control group, and the intervention in 2 groups lasted for 3 months. The indexes of liver function, glucose and lipids metabolism, NAFLD activity score (NAS), and conditions of fecal flora in 2 groups were compared before and after the treatment.Before the treatment, there were no significant differences on alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamine transferase (GGT), total bilirubin (TBIL), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), insulin resistance index (HOMA-IR), NAFLD activity score (NAS), and conditions of fecal flora in 2 groups (P > .05). After the treatment, ALT, AST, GGT, TC, TG, HOMA-IR, NAS, and conditions of fecal flora in the observation group were better than those in the control group, and the observation group was better after treatment than before. All these above differences were statistically significant (P < .05).Probiotics can improve some liver functions, glucose and lipids metabolism, hepatic fatty deposition in patients with NAFLD, which will enhance the therapeutic effects of NAFLD.
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Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men.
Dollerup, OL, Chubanava, S, Agerholm, M, Søndergård, SD, Altıntaş, A, Møller, AB, Høyer, KF, Ringgaard, S, Stødkilde-Jørgensen, H, Lavery, GG, et al
The Journal of physiology. 2020;598(4):731-754
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Preclinical evidence suggests that the nicotinamide adenine dinucleotide (NAD+) precursor nicotinamide riboside (NR) boosts NAD+ levels. Boosting NAD+ metabolism has emerged as a promising strategy to counter age-related functional decline and promote healthy ageing. Progressive deterioration of mitochondrial function and NAD+ metabolism are hallmarks of ageing of human tissue. The aim of this study was to determine if NR supplementation in humans impacts NAD+ metabolism and mitochondrial respiration in skeletal muscle. This study is a randomised, double-blinded, placebo-controlled clinical trial. Participants were randomised into two groups: NR (n=20) and placebo (n=20). Results show that 12 weeks of oral NR supplementation (2000 mg/day) decreased nicotinamide phosphoribosyltransferase protein levels [an enzyme] in muscle without affecting cellular NAD+ content. Despite changes in nicotinamide phosphoribosyltransferase, neither beneficial nor detrimental effects on mitochondrial respiration, content or dynamics were observed in skeletal muscle. Authors conclude that NR supplementation does not enhance aspects of mitochondrial function in human skeletal muscle of middle-aged, obese, insulin-resistant healthy males.
Abstract
KEY POINTS This is the first long-term human clinical trial to report on effects of nicotinamide riboside (NR) on skeletal muscle mitochondrial function, content and morphology. NR supplementation decreases nicotinamide phosphoribosyltransferase (NAMPT) protein abundance in skeletal muscle. NR supplementation does not affect NAD metabolite concentrations in skeletal muscle. Respiration, distribution and quantity of muscle mitochondria are unaffected by NR. NAMPT in skeletal muscle correlates positively with oxidative phosphorylation Complex I, sirtuin 3 and succinate dehydrogenase. ABSTRACT Preclinical evidence suggests that the nicotinamide adenine dinucleotide (NAD+ ) precursor nicotinamide riboside (NR) boosts NAD+ levels and improves diseases associated with mitochondrial dysfunction. We aimed to determine if dietary NR supplementation in middle-aged, obese, insulin-resistant men affects mitochondrial respiration, content and morphology in skeletal muscle. In a randomized, placebo-controlled clinical trial, 40 participants received 1000 mg NR or placebo twice daily for 12 weeks. Skeletal muscle biopsies were collected before and after the intervention. Mitochondrial respiratory capacity was determined by high-resolution respirometry on single muscle fibres. Protein abundance and mRNA expression were measured by Western blot and quantitative PCR analyses, respectively, and in a subset of the participants (placebo n = 8; NR n = 8) we quantified mitochondrial fractional area and mitochondrial morphology by laser scanning confocal microscopy. Protein levels of nicotinamide phosphoribosyltransferase (NAMPT), an essential NAD+ biosynthetic enzyme in skeletal muscle, decreased by 14% with NR. However, steady-state NAD+ levels as well as gene expression and protein abundance of other NAD+ biosynthetic enzymes remained unchanged. Neither respiratory capacity of skeletal muscle mitochondria nor abundance of mitochondrial associated proteins were affected by NR. Moreover, no changes in mitochondrial fractional area or network morphology were observed. Our data do not support the hypothesis that dietary NR supplementation has significant impact on skeletal muscle mitochondria in obese and insulin-resistant men. Future studies on the effects of NR on human skeletal muscle may include both sexes and potentially provide comparisons between young and older people.