LAUSR

Dear Editor, Aging is a part of human life. Prolonging life span and reducing disease have always been the focus of human attention. With the aging of the population in the economically developed countries, prolonging the life span of the elderly and maintaining their quality of life become an effective way to reduce the social and economic burden of each country, especially the developed countries [1]. At present, there are mainly two anti-aging methods, which are divided into non-drug interventions and drug interventions. Non-pharmacological interventions included intermittent or prolonged fasting, mild calorie restriction (CR) combined with low glycemic index diet, protein restriction diet, and regular physical exercise. The main drug interventions are metformin, acarbose, spermidine, statins, B-blockers, rapamycin, and resveratrol. These antiaging measures have shown certain anti-aging efficacy in studies [2]. As cosmetic plastic surgeons, we are more concerned with the anti-aging treatment of the facial skin. Recently, we read the published study by Alissa Davis and Adam Augenstein that amniotic allograft implantation for midface aging correction: a retrospective comparative study with platelet-rich plasma [3], carefully. In this article, the authors compared the efficacy of allogeneic amniotic membrane transplantation with platelet-rich plasma in the anti-aging treatment of facial skin. This study provided an important reference for plastic surgeons in anti-aging treatment of facial skin. However, the efficacy of these two facial anti-aging treatments is short, and the use of sharp needle syringes to inject drugs into the skin, which can cause pain, edema, hematoma, infection, and even immune rejection. Therefore, we think that these two methods are not the best anti-aging treatment methods for facial skin. In recent years, the biological study of nicotinamide adenine dinucleotide (NAD?) has developed rapidly, providing many important discoveries on the pathogenesis of age-associated functional decline and diseases in humans. In particular, two key NAD? intermediates, nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), have attracted extensive attention from researchers [4]. NMN can be synthesized in two ways (Fig. 1). One way is synthesized from a nicotinamide of water-soluble vitamin B3 and 50-phosphoribosyl-1-pyrophosphate by nicotinamide phosphoribosyltransferase (NAMPT) [5]. The other way is synthesized from NR through NR kinases (NRK)mediated phosphorylation reactions. NMN can be converted into NAD? by catalysis of NMN adenylyltransferases (NMNATs), thus increasing the level of NAD? to achieve the effect of anti-aging. While the anti-aging function of NMN has been confirmed, NMN has not yet been officially approved for use in anti-aging therapy. Compared with NMN, we believe that NR will be a & Bo Pan [email protected]