Protective Effects of Nicotinamide Adenine Dinucleotide and Related Precursors in Alzheimer's Disease: A Systematic Review of Preclinical Studies.

Data from preclinical studies propose nicotinamide adenine dinucleotide (NAD+) as a neuroprotective and bioenergetics stimulant agent to treat Alzheimer's disease (AD); however, there seems to be inconsistency between behavioral and molecular outcomes. We performed this systematic review to provide a better understanding of the effects of NAD+ in rodent AD models and to summarize the literature.Studies were identified by searching PubMed, EMBASE, Scopus, Google Scholar, and the reference lists of relevant review articles published through December 2020. The search strategy was restricted to articles about NAD+, its derivatives, and their association with cognitive function in AD rodent models. The initial search yielded 320 articles, of which 11 publications were included in our systematic review.Based on the primary outcomes, it was revealed that NAD+ improves learning and memory. The secondary endpoints also showed neuroprotective effects of NAD+ on different AD models. The proposed neuroprotective mechanisms included, but were not limited to, the attenuation of the oxidative stress, inflammation, and apoptosis, while enhancing the mitochondrial function.The current systematic review summarizes the preclinical studies on NAD+ precursors and provides evidence favoring the pro-cognitive effects of such components in rodent models of AD.

Effects of Zataria oxymel on obesity, insulin resistance and lipid profile: A randomized, controlled, triple-blind trial.

BACKGROUND: Obesity is a major public health problem and its occurrence is markedly increasing in developed and developing countries. However, few studies have investigated the use of natural products to treat obesity. The effects of taking a combination of oxymel and Zataria multiflora Boiss. (ZM), herein referred to as Zataria oxymel (ZO), on obesity, lipid profile and insulin resistance have not yet been studied. OBJECTIVE: This study evaluates the effects of oxymel and ZO on obesity, lipid profile and insulin resistance. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS: In this randomized, controlled, triple-blind trial, overweight patients were randomly divided into three groups and received doses of study compounds twice per day for twelve weeks. Group A received 0.75 g ZM in 10 mL oxymel in each treatment; group B received 1.5 g ZM in 10 mL of oxymel in each treatment and group C (control) only received 10 mL of oxymel in each treatment. MAIN OUTCOME MEASURES: Anthropometric parameters, including body mass index (BMI), waist circumference and hip circumference, were measured at the time of registration. Blood tests were carried out at the beginning and once again at end of the study. Blood parameters included fasting blood sugar (FBS), insulin levels, serum lipid profile (total cholesterol, triglyceride, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol) and liver enzymes (aspartate transaminase and alanine transaminase). Serum creatinine was also measured at the beginning of the project and in monthly intervals for three months. The homeostasis model assessment index was calculated as fasting insulin (µIU/mL) × FBS (mg/dL)/405. RESULTS: The results showed that patients receiving ZO experienced significant reduction in waist circumference in groups A, B and C, respectively (P < 0.001) but no significant change in BMI. Group A also experienced reduction in hip circumference (P = 0.01). Groups B and C had reduction in the homeostatic model assessment of insulin resistance (P = 0.05 and P = 0.01, respectively), with no significant reduction in FBS. No effect on lipid profile, liver enzymes or serum creatinine was observed in the three groups. CONCLUSION: In this study, treatment with ZO and oxymel reduced insulin resistance, and waist and hip circumferences in overweight patients. Nonetheless, the traditional Persian use of ZO as a beverage to improve the anthropometric indices in overweight individuals still requires further research with a larger sample size. TRIAL REGISTRATION: Iranian Registry of Clinical Trials Code IRCT20171220037976N1.

Nicotinamide adenine dinucleotide emerges as a therapeutic target in aging and ischemic conditions.

Nicotinamide adenine dinucleotide (NAD+) has been described as central coenzyme of redox reactions and is a key regulator of stress resistance and longevity. Aging is a multifactorial and irreversible process that is characterized by a gradual diminution in physiological functions in an organism over time, leading to development of age-associated pathologies and eventually increasing the probability of death. Ischemia is the lack of nutritive blood flow that causes damage and mortality that mostly occurs in various organs during aging. During the process of aging and related ischemic conditions, NAD+ levels decline and lead to nuclear and mitochondrial dysfunctions, resulting in age-related pathologies. The majority of studies have shown that restoring of NAD+ using supplementation with intermediates such as nicotinamide mononucleotide and nicotinamide riboside can be a valuable strategy for recovery of ischemic injury and age-associated defects. This review summarizes the molecular mechanisms responsible for the reduction in NAD+ levels during ischemic disorders and aging, as well as a particular focus is given to the recent progress in the understanding of NAD+ precursor's effects on aging and ischemia.