Nicotinic acid: clinical considerations

The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update

The importance of nicotinamide adenine dinucleotide (NAD+) in human physiology is well recognized. As the NAD+ concentration in human skin, blood, liver, muscle, and brain are thought to decrease with age, finding ways to increase NAD+ status could possibly influence the aging process and associated metabolic sequelae. Nicotinamide mononucleotide (NMN) is a precursor for NAD+ biosynthesis, and in vitro/in vivo studies have demonstrated that NMN supplementation increases NAD+ concentration and could mitigate aging-related disorders such as oxidative stress, DNA damage, neurodegeneration, and inflammatory responses. The promotion of NMN as an antiaging health supplement has gained popularity due to such findings; however, since most studies evaluating the effects of NMN have been conducted in cell or animal models, a concern remains regarding the safety and physiological effects of NMN supplementation in the human population. Nonetheless, a dozen human clinical trials with NMN supplementation are currently underway. This review summarizes the current progress of these trials and NMN/NAD+ biology to clarify the potential effects of NMN supplementation and to shed light on future study directions.

Analysis of different plant- and animal-based dietary patterns and their relationship with serum uric acid levels in Chinese adults

BACKGROUND

Dietary patterns play an important role in regulating serum uric acid levels in the body, but evidence for the association between different kinds of plant-based and animal-based dietary patterns and individual serum uric acid levels is scarce and inconsistent.

METHODS

We analyzed data from the sixth wave of the China Health and Nutrition Survey. The plant-based diet of 7,806 participants was determined using three consecutive 24-hour dietary recalls, and latent profile analysis was used to identify dietary patterns among participants. Serum uric acid levels were analyzed using the enzymatic colorimetric method. The association between intakes of different types of dietary pattern and individual serum uric acid levels was analyzed using linear regression analysis, after adjusting for confounding variables.

RESULTS

We identified three types of plant-based dietary patterns, namely, low tuber starches and vegetable plant-based diet (LTVP), high cereal, tuber starches and vegetable plant-based diet (HCTVP), and high legume and fruit plant-based diet (HLFP). We also identified three types of animal-based dietary patterns, namely, high milk and egg animal-based diet (HMiEA), low egg and fish animal-based diet, and high meat and fish animal-based diet (HMeFA). Significant coefficients for participant serum uric acid levels were observed for the HCTVP diet (β = -0.022, P = 0.031) and HMeFA diet (β = 0.061, P < 0.001). The median intake of foods in the HCTVP diet was as follows: cereals and cereal products, 444.83 g/d; tubers and starch products, 166.67 g/d; dried legumes and legume products, 8.33 g/d; vegetables and vegetable products, 333.33 g/d; and fruits and fruit products, 0 g/d. The median intake of foods in the HMeFA diet was as follows: meat and meat products, 73.33 g/d; poultry and poultry products, 0 g/d; milk and milk products, 0 g/d; eggs and egg products, 26.67 g/d; and fish, shellfish, and mollusks, 180.00 g/d.

CONCLUSION

We showed that individual serum uric acid levels (1) might decrease under the plant-based HCTVP diet, (2) might increase under the animal-based HMeFA diet, (3) might not decrease under the plant-based HLFP diet, and (4) might not increase under the animal-based HMiEA diet. Further studies are needed to confirm these associations.

Anaphylactoid reactions induced by Shuanghuanglian injection and Shenmai injection and metabolomics analysis

Introduction: Shuanghuanglian injection (lyophilized) (SHLI) is commonly used to treat respiratory tract infection. Shenmai injection (SMI) is mainly used to treat cardiovascular diseases. Despite their widespread clinical use, anaphylactoid reactions (ARs) induced by SHLI and SMI have been reported, which have attracted broad attention. However, the impact of ARs on metabolic changes and the underlying mechanisms are still unclear. Methods: ICR mice were used as model animals and were treated with normal saline, C48/80, SHLI and SMI, respectively. The behavior of mice, auricle blue staining and Evans Blue exudation were used as indexes to evaluate the sensitization of SHLI and SMI and determine the optimal sensitization dose. Anaphylactoid mice model was established based on the optimal dose and enzyme-linked immunosorbent assay (ELISA) was used to model verification. Afterwards, plasma samples of administered mice were profiled by LC-MS metabolomics and analyzed to evaluate the changes in metabolites. Results: High doses of both SHLI and SMI can induce severe anaphylactoid reactions while the reaction induced by SMI was weaker. A Partial Least-Squares Discriminant Analysis (PLS-DA) score plot indicated that following administration, significant metabolic changes occurred in mice. 23 distinct metabolites, including deoxycholic acid, histamine, and 5-hydroxytryptophan, were identified in the SHLI groups. 11 distinct metabolites, including androsterone, 17α-hydroxypregnenolone, and 5-hydroxyindoleacetate, were identified in the SMI groups. Meanwhile, different metabolic pathways of SHLI and SMI were predicted by different metabolites. The associated metabolic pathways include steroid hormone biosynthesis, tryptophan metabolism, histidine metabolism, arachidonic acid metabolism, nicotinate and nicotinamide metabolism, and primary bile acid biosynthesis. Conclusion: Study showed that both SHLI and SMI can induce varying degrees of anaphylactoid reactions, a positive correlation between response intensity and dose was observed. Metabolomics showed that SHLI and SMI may promote the simultaneous release of hormones and inflammatory factors by disturbing relevant metabolic pathways, while SMI may also inhibit the release of inflammatory factors in arachidonic acid metabolic pathway, indicating both pro-inflammatory and anti-inflammatory effects. This study will serve as a reference for developing a new approach to evaluate the safety of SHLI and SMI from perspective of susceptible drug varieties. However, ARs mechanism requires further verification.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

Dose-response association between dietary folate and niacin intakes with diabetes among Chinese adults: a cross-sectional study

BACKGROUND

The aim of this study was to examine the relationship between dietary intake of folate and niacin and diabetes risk in Chinese adults.

METHODS

This is a cross-sectional study. Demographic and anthropometric data along with information on dietary intake of vitamins were collected, and eligible participants were recruited to complete the questionnaire. A binary logistic regression analysis was conducted to examine the association between dietary intake of vitamins and diabetes risk, with adjustment for potential confounders. Non-linear dose-response relationships between dietary intake of folate and niacin and diabetes risk were also evaluated using adjusted restricted cubic splines.

RESULTS

Of the 3106 eligible participants, 15.9% had diabetes. Median folate was significantly higher in diabetic patients than in controls (32.030 vs. 27.600 gμ), while median niacin was significantly lower (7.000 vs. 7.900 mg). After controlling for potential confounders, binary logistic regression analysis showed that each unit increase in folate intake was associated with a 1.002-fold increase in the risk of developing diabetes (odds ratio (OR) = 1.002; 95% confidence interval (CI) 1.000-1.004; P = 0.022), while each unit increase in niacin intake was associated with a 3.5% reduction in diabetes risk (OR = 0.965; 95% CI 0.944-0.986; P = 0.001). The plots of restricted cubic splines presented an atypical inverted U-shaped association between dietary intake of folate and diabetes risk.

CONCLUSIONS

Diabetic patients had a low intake of vitamins, especially the B vitamins. Dietary intake of folate and niacin tended to be independently associated with the risk of diabetes. Nevertheless, this study is observational and a large-scale randomized controlled trial is yet to be conducted, which will add to the evidence of the study results.

TMT-based proteomics analysis reveals the efficacy of jiangzhuo formula in improving the lipid profiles of dyslipidemia rats

ETHNOPHARMACOLOGICAL RELEVANCE

Jiangzhuo Formula (JZF) is a traditional Chinese herbal prescription that is clinically applied to treat dyslipidemia. However, the mechanism underlying its efficacy remains unexplored.

AIM OF THE STUDY

This study aims to elucidate the underlying mechanisms, explore potential pathways, and identify the key proteins of JZF for the treatment of dyslipidemia.

METHODS

In this work, Q-Orbitrap high-resolution liquid chromatography mass spectrometry was used to identify the natural ingredients in JZF, rats with dyslipidemia were established via a high-fat diet for four weeks, then the dyslipidemia rats were treated with high-dose JZF (9 g/d) and low-dose JZF (4.5 g/d) for four weeks. After treatment, serum lipid detection and Oil-red-O staining were conducted to assess the efficacy of JZF in ameliorating dyslipidemia. Tandem mass tag (TMT) -based quantitative proteomics technology was then used to evaluate the roles and importance of proteins from the extracted hepatic tissue. The differentially expressed proteins were assessed by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, Gene Ontology (GO), and protein-protein interaction (PPI) networks. Western blot and PCR analysis were used to validate the potential targets regulated by JZF.

RESULTS

JZF could significantly improve the blood lipid profiles of serum and fat deposits of the liver. A total of 123 differentially expressed proteins were detected after JZF intervention, comprising 65 up-regulated proteins and 58 down-regulated proteins. The KEGG pathway analysis revealed that cholesterol metabolism, the PPAR signaling pathway, and bile secretion were the principal pathways involved in the disordered lipid metabolism, while GO analysis suggested that proteins that are located in the cell, regulate cellular processes, and show binding activity contribute to reductions in lipids. The combination of proteomics, Western blot, and PCR suggested that Apolipoprotein B (APOB), Apolipoprotein E (APOE), cholesterol 7 alpha-hydroxylase A1 (CYP7A1), and Hydroxymethylglutaryl-CoA synthase 1 (HMGCS1) might play critical roles in JZF's lipid-lowering network.

CONCLUSION

JZF can effectively improve lipid profiles via multiple pathways involved in cholesterol metabolism, the PPAR signaling pathway, and bile secretion. Generally, the proteomics techniques used in this research show that JZF could be a promising drug for the treatment of dyslipidemia.

Comparative effect of nutraceuticals on lipid profile: a protocol for systematic review and network meta-analysis

INTRODUCTION

According to the common definition, nutraceuticals are components found in food that can act as therapeutic substances. Recently, the International Lipid Expert Panel published two position papers covering the topic of lipid-lowering nutraceuticals and their potential use as a complementary treatment in addition to statins or as an alternative treatment in statin-intolerant patients. The aim of this study was to compare the effect of different nutraceuticals on lipid profiles in a systematic review with pairwise and network meta-analyses.

METHODS AND ANALYSIS

Three databases, including PubMed, Embase and the Cochrane Central Register of Controlled Trials, will be searched without time or publication language restrictions. The estimated end date for the searches will be 29 March 2020. Each stage of the review, including the study section, data extraction, and risk of bias and quality of evidence assessments, will be performed in duplicate. Randomised controlled trials meeting the following criteria will be eligible for inclusion: (1) participants aged ≥18 years, (2) intervention with a selected nutraceutical (artichoke, berberine, bergamot, soluble fibres, green tea, garlic, lupin, plant sterols and stanols, red yeast rice, soybean, spirulina or a combination of the aforementioned nutraceuticals), (3) administration of the treatment in the form of capsules, pills, powders, solutions, tablets or enriched food items, (4) comparison with another nutraceutical or placebo, (5) intervention period ≥3 weeks and (6) lipid profile (low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total cholesterol, triglycerides) as an outcome. Random-effect pairwise and network meta-analyses will be used to summarise the relative effect of each nutraceutical in comparison to the effect of every other nutraceutical. Subgroup analyses will be stratified by age, sex, ethnicity, sample size, length of trial follow-up, baseline cholesterol level and presence of other comorbidities.

ETHICS AND DISSEMINATION

This review will summarise findings from primary studies, and therefore no ethics approval is required. The results will be presented at conferences as well as published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42019132877.

N2L, a novel lipoic acid-niacin dimer protects HT22 cells against β-amyloid peptide-induced damage through attenuating apoptosis

β-amyloid protein (Aβ) is thought to be the primary cause of the pathogenesis of Alzheimer's disease (AD). Niacin has been reported to have beneficial effects on AD. Previously, we synthesized a novel compound lipoicacid-niacin dimer (N2L) and revealed that it had potent blood-lipid regulation and antioxidative properties without aflushing effect. Given that lipid metabolism is also associated with AD, the present study aimed to investigate the neuroprotective effects of N2L on Aβ_1-42-induced cytotoxicity in HT22 cells. We found that N2L significantly attenuated cell apoptosis, MDA level, ROS content, and the mitochondrial membrane potential corruption induced by Aβ_1-42 in HT22 cells. In addition, the activities of SOD, GSH-px and CAT that were decreased by Aβ_1-42 were also restored by N2L. Furthermore, N2L reduced proapoptotic signaling by increasing the expression of anti-apoptotic Bcl-2 and decreasing the protein expression of both pro-apoptotic Bax and cleaved Caspase-3. Together, these findings indicate that N2L holds great potential for neuroprotection against Aβ_1-42-induced cytotoxicity via inhibition of oxidative stress and cell apoptosis, suggesting that N2L may be a promising agent for AD therapy.

Drug-induced hyperuricaemia and gout

Hyperuricaemia is a common clinical condition that can be defined as a serum uric acid level >6.8 mg/dl (404 µmol/l). Gout, a recognized complication of hyperuricaemia, is the most common inflammatory arthritis in adults. Drug-induced hyperuricaemia and gout present an emergent and increasingly prevalent problem in clinical practice. Diuretics are one of the most important causes of secondary hyperuricaemia. Drugs raise serum uric acid level by an increase of uric acid reabsorption and/or decrease in uric acid secretion. Several drugs may also increase uric acid production. In this review, drugs leading to hyperuricaemia are summarized with regard to their mechanism of action and clinical significance. Increased awareness of drugs that can induce hyperuricaemia and gout, and monitoring and prevention are key elements for reducing the morbidity related to drug-induced hyperuricaemia and gout.

Nicotinic acid supplementation in the context of alcoholic liver injury: friend or foe?

Li and colleagues (2014) in this issue report that dietary nicotinic acid (NA) supplementation ameliorates ethanol-induced hepatic steatosis, but a deficiency does not worsen injury induced by alcohol alone. The authors further present some mechanistic insights into the protective role of NA supplementation. Results of this and other previous studies in the context of alcoholic liver injury raise one important question as to what should be an adequate dose of NA that will provide the maximum benefit to hepatic and extrahepatic tissues and with minimum adverse effects.

Normalizing metabolism in diabetic pregnancy: is it time to target lipids?

Outcomes in pregnancies complicated by preexisting diabetes (type 1 and type 2) and gestational diabetes mellitus have improved, but there is still excess morbidity compared with normal pregnancy. Management strategies appropriately focus on maternal glycemia, which demonstrably improves pregnancy outcomes for mother and infant. However, we may be reaching the boundaries of obtainable glycemic control for many women. It has been acknowledged that maternal lipids are important in pregnancies complicated by diabetes. Elevated maternal lipids are associated with preeclampsia, preterm delivery, and large-for-gestational-age infants. Despite this understanding, assessment of management strategies targeting maternal lipids has been neglected to date. Consideration needs to be given to whether normalizing maternal lipids would further improve pregnancy outcomes. This review examines the dyslipidemia associated with pregnancy complicated by diabetes, reviews possible therapies, and considers whether it is time to start actively managing this aspect of maternal metabolism.