10月では以下の最新情報をご紹介します。① NMNがヒト骨細胞培養において老化促進細胞を減少させ、骨形成を促すことが示されました。また、骨粗鬆症モデルのマウスにNMNを注射すると骨量が増大することが確認されました。以下研究の詳細です。1.私たちの骨は年齢とともに骨量や骨密度が低下し、その結果骨折の原因となります。特に骨粗鬆症は現代において、悩まされている人も多く、改善するための方法が模索されています。本研究では、NMNは、老化によって増える骨を作る細胞の老化（セネッセンス）を減らし、骨を作る細胞の分化を促進することが人間の細胞培養で示されました。また、NMNは、骨粗しょう症のマウスモデルに注射すると、骨量が増加することが示された。その結果NMNは、骨粗しょう症の予防や治療に有効な候補薬となる可能性があると結論づけられています。表題：Nicotinamide Mononucleotide Alleviates Osteoblast Senescence Induction and Promotes Bone Healing in Osteoporotic Mice＜地域＞オーストラリア・シドニー大学＜対象＞ヒト細胞、骨粗鬆症マウス＜引用＞ZuFu Lu, Liting Jiang, Pooria Lesani, WenJie Zhang, Ning Li, Danyang Luo, Yusi Li, Yulin Ye, Ji Bian, Guocheng Wang, Colin R Dunstan, XinQuan Jiang, Hala Zreiqat, Nicotinamide Mononucleotide Alleviates Osteoblast Senescence Induction and Promotes Bone Healing in Osteoporotic Mice, The Journals of Gerontology: Series A, Volume 78, Issue 2, February 2023, Pages 186–194, https://doi.org/10.1093/gerona/glac175＜URL＞https://academic.oup.com/biomedgerontology/article-abstract/78/2/186/6678612?redirectedFrom=fulltext＜注目ポイント＞骨折の再生等、これまでも骨とNMNに着目した研究を取り上げてきました。本件ではヒト細胞とマウスを使い、作用機序含めて調べているため、今後の高齢社会における課題の一つである骨粗鬆症への対策としての可能性を示しています。――以下、研究、トピックの詳細（翻訳）――＜研究＞1. Nicotinamide Mononucleotide Alleviates Osteoblast Senescence Induction and Promotes Bone Healing in Osteoporotic Mice要約蓄積した老化細胞と闘い、高齢者の骨粗鬆症性骨折を治癒させることは、依然として重要な課題である。NAD+の前駆体であるニコチンアミドモノヌクレオチド（NMN）は、老化関連障害を緩和する優れた候補物質である。しかしながら、NMNが老化細胞の誘導を緩和し、骨粗鬆症性骨折の治癒を促進できるかどうかは不明である。ここで我々は、NMN投与がヒト初代骨芽細胞（HOBs）に対する腫瘍壊死因子α（TNF-α）の影響（老化細胞誘導、骨形成分化能の低下、細胞内NAD+およびNADHレベル）を部分的に逆転させることを示した。メカニズム的には、NMNはTNF-αによって誘導されたHOBのミトコンドリア機能障害を回復させ、それはミトコンドリア膜電位の上昇、反応性酸化種およびミトコンドリア量の減少によって証明された。NMNはまた、P62の発現をダウンレギュレートし、軽鎖3B-IIタンパク質の発現をアップレギュレートすることによって、マイトファジー活性を増加させる。さらに、HOBに対するNMNの細胞老化防止効果は、マイトファジー阻害剤（バフィロマイシンA1）によって軽減される。In vivoでは、NMNの補給は成長板における老化細胞の誘導を減衰させ、卵巣摘出マウスモデルにおける骨粗鬆症を部分的に予防し、骨粗鬆症マウスの骨治癒を促進した。我々は、NMNが高齢者の骨折治癒能力を高める新規かつ有望な治療候補となりうると結論付けた。＜引用＞ZuFu Lu, Liting Jiang, Pooria Lesani, WenJie Zhang, Ning Li, Danyang Luo, Yusi Li, Yulin Ye, Ji Bian, Guocheng Wang, Colin R Dunstan, XinQuan Jiang, Hala Zreiqat, Nicotinamide Mononucleotide Alleviates Osteoblast Senescence Induction and Promotes Bone Healing in Osteoporotic Mice, The Journals of Gerontology: Series A, Volume 78, Issue 2, February 2023, Pages 186–194, https://doi.org/10.1093/gerona/glac175

https://www.arnan.or.jp/2023年９月の最新新着情報　　NMN機能性食品開発協会　橋本圭司9月では以下の最新情報をご紹介します。集英社新書にて米井嘉一先生著「若返りホルモン」という本にて、1ページ程度でしたがNMNが紹介されていました。DHEA（デヒドロエピアンドロステロン）というホルモンを取り上げた著書になります。DHEAとは、副腎や性腺で合成されるステロイドホルモンの一種で、男性ホルモンや女性ホルモンの原料になります。DHEAは、抗酸化作用や免疫力の維持、性機能の改善など、さまざまな効果があると言われています。DHEAは、加齢とともに減少するため、若返りやアンチエイジングに興味がある人に注目されています。この著書ではNMNがDHEAを増やすサプリメントとして紹介されていました。その理由としては、以前にご紹介した同志社で行われた臨床研究においてNMN摂取がDHEAが増加しており、その理由の仮説として、DHEA産生細胞のNAD+が増えて細胞機能が活性化したこと、糖化ストレスの軽減によりDHEA産生細胞内の老廃物が減ったことが挙げられていました。米国でのNMNの取り扱いに関しては、既報の通り2023年3月、Natural Products Association（NPA）とAlliance for Natural Health USAは食品医薬品局（FDA）に要望書を提出した後は進展がありません。FDAはNMNを医薬品として研究されていることを理由にサプリメントとしての販売を禁止する通知を出す前に、NMNを新規栄養成分（NDI）、すなわち栄養補助食品の添加物として認めていました。そのNDIについて、FDAは後に、NMNとMIB-626（メトロ・インターナショナル・バイオテック社が新薬として調査中のNMNの独自製剤）との関連はすぐには分からなかったと述べていますが、その対応に対して批判がされています。　FDAによるNMNのサプリメントとしての定義からの除外決定は、2022年に米国で推定2億8,020万ドルと評価されるNMN市場に甚大な悪影響を及ぼし始めているとの指摘もあります。FDAは最近の書簡で、栄養補助食品に含まれるNMNに関する市民請願について、実質的な決定に至っていない理由を "競合する省庁の優先事項 "を挙げており、上記要望書や下院議会での質問状に対して明確な回答を引き延ばしていますが、状況次第ではNPAやAlliance for Natural Health USAによる訴訟が準備されているとの情報もあります（参考1）。①指先から採取されるわずかな血液で血中のNAD+を高精度で測定できる手法が開発されました。それを元にNMNを30日間毎日500㎎経口投与した結果を測定すると血中NAD+がほぼ2倍になり、NMNを1,000mg投与すると血中NAD+がさらに30％増加することが示されました。②NMNを添加した温度感受性ハイドロゲルが糖尿病の皮膚創傷において細胞増殖や血管新生を通して治癒を促すことが示唆されました。③高血圧患者に1日800mgのNMNを6週間経口摂取させると、血圧が有意に低下するという研究が報告されました。以下それぞれの研究の詳細です。1.本研究では、NAD+の血液中における濃度が加齢や性別によってどのように変化するかを調べるために、5 μLの毛細血管血を使ってNAD+を迅速に測定できる自動化されたNAD+分析装置を開発したと報告しています。人間のNAD+の状態は個人差が大きく、低侵襲で低コストな測定法がないため、全血中のNAD+の基準値を確立したり、従来のNAD+サプリメントに対する反応が悪い人に対する個別化された治療法を開発したりすることが困難でした。著者らは、再結合型発光センサータンパク質と自動光学リーダーを用いて、毛細血管血からNAD+を測定することができる分析装置を開発しました。この装置の最小検出限界は0.5 μMであり、従来の高速液体クロマトグラフィーや質量分析法と同等の精度でNAD+を測定できることを実証しました。この装置を用いて、有酸素運動やNMNサプリメント（500mg、1000mg）摂取が全血中のNAD+を増加させることを示しました。また、50歳未満では男性の方が女性よりも平均的に高いNAD+を持っていることや、NAD+レベルの変動を調査した結果では100日間以上安定しており、NMNの継続的な経口投与と運動によってNAD＋レベルを高めることができることが立証されました。表題：Fingerstick blood assay maps real-world NAD+ disparity across gender and age＜地域＞中国科学院深圳先端技術研究所＜対象＞人間＜引用＞Wang P, Chen M, Hou Y, Luan J, Liu R, Chen L, Hu M, Yu Q. Fingerstick blood assay maps real-world NAD+ disparity across gender and age. Aging Cell. 2023 Aug 28:e13965. doi: 10.1111/acel.13965. Epub ahead of print. PMID: 37641521.＜URL＞https://onlinelibrary.wiley.com/doi/10.1111/acel.13965＜注目ポイント＞NMNやNAD+ブースターの研究において、体内・血中のNAD+の測定は必要不可欠です。高精度かつ簡便な本研究の手法が普及すると、よりNMN等の研究のハードルが下がり、様々なデータも集まるため非常に興味深い研究となっています。2.糖尿病における合併症の足潰瘍は、死亡率も高く、現行の治療法では重大な副作用や高額な費用、満足のいくような結果が得られないなど様々な課題があり、糖尿病性足潰瘍の治癒を安全かつ効果的に促進できる治療法の開発が急務となっています。従来、ドレッシング材は主に創傷を感染から守るための物理的バリアを確立するために使用されてきましたが、これらのドレッシング材には機能的な有効性が欠けていました。しかし近年創傷治癒を促進するため、抗菌性や組織再生特性を持つ化合物を組み込んだ機能性ドレッシング材が開発され、その有効性が高まっています。本研究ではNMNを添加した温度感受性ハイドロゲルを開発し、その効果を調べました。　その結果、細胞増殖、遊走、血管新生を促進したことを確認し、実際に糖尿病モデルマウスの皮膚創傷モデルにおいて、in-vivoでの有効性が証明されました。　NMNを添加した温度感受性ハイドロゲルは、簡便で経済的、効果的かつ安全な方法で糖尿病創傷の治癒を促進することができ、糖尿病創傷の治療に応用できる可能性が示されました。表題：Temperature-sensitive hydrogel dressing loaded with nicotinamide mononucleotide accelerating wound healing in diabetic mice＜実施場所＞中国上海市復旦大学生命科学院遺伝学研究所＜対象＞in vitro、糖尿病モデルマウス＜引用＞Yue Liang, Min Li, Yuan Tang, Jinlong Yang, Jing Wang, Yuqi Zhu, Huitong Liang, Qinru Lin, Yipen Cheng, Xinyi Yang, Huanzhang Zhu,Biomedicine & Pharmacotherapy,Volume 167,2023,115431,ISSN 0753-3322,https://doi.org/10.1016/j.biopha.2023.115431.＜URL＞https://www.sciencedirect.com/science/article/pii/S07533322230122953.高血圧は、脳卒中、虚血性心疾患、腎疾患による850万人の死亡の原因となっており、公衆衛生上の大きな問題です。高血圧は一種の老化関連疾患として認められており、これまでのNMN摂取による老化の防止効果を鑑みると、治療法の一つとしての可能性が考えられます。本研究では、高血圧でNAD+のレベルがどのように低下するかを知るために、大動脈の内皮細胞で、NAD+を消費する酵素CD38のレベルを測定しました。CD38 はNAD+やNMNを分解する働きが知られています。その結果、高血圧でない健康な成人と比較して、高血圧患者ではCD38レベルが2倍以上高いことを発見しました。これらの結果は、高血圧患者の内皮細胞におけるCD38レベルの上昇が、NAD+レベルの低下に寄与していることを示唆すると本研究では考えました。そして、高血圧患者にNMNを毎日800㎎摂取して調査したところ、血圧が有意に低下し、血球NAD+濃度が43％上昇することを確認しました。表題：NAD+ exhaustion by CD38 upregulation contributes to blood pressure elevation and vascular damage in hypertension＜実施場所＞孫文大学第一附属病院、中国＜対象＞健康な被験者52人と新たに高血圧と診断された患者50人を含む102人、in vivo、in vitro＜引用＞Qiu Y, Xu S, Chen X, Wu X, Zhou Z, Zhang J, Tu Q, Dong B, Liu Z, He J, Zhang X, Liu S, Su C, Huang H, Xia W, Tao J. NAD+ exhaustion by CD38 upregulation contributes to blood pressure elevation and vascular damage in hypertension. Signal Transduct Target Ther. 2023 Sep 18;8(1):353. doi: 10.1038/s41392-023-01577-3. PMID: 37718359; PMCID: PMC10505611.＜URL＞https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10505611/――以下、研究、トピックの詳細（翻訳）――＜研究＞1.Fingerstick blood assay maps real-world NAD+ disparity across gender and age要約ニコチンアミドアデニンジヌクレオチド（NAD+）レベルは、様々な加齢関連疾患と関連しており、その薬理学的調節は加齢介入への潜在的アプローチとして浮上している。しかし、ヒトのNAD+動態は大きな不均一性を示している。迅速で低コストのアッセイがないため、全血NAD+ベースラインの確立や、特に従来のNAD+補充に対する反応が乏しい人々に対する個別化治療の開発が制限されている。ここでわれわれは、組換え生物発光センサータンパク質と自動光学リーダーを用いて、5μLのキャピラリー血液でNAD+を迅速に測定する自動NAD+分析装置を開発した。このアッセイの最小限の侵襲性により、実世界のNAD+動態の頻繁かつ分散的なマッピングが可能となった。我々は、有酸素スポーツとNMN補給が全血NAD+を増加させ、50歳以前は平均して男性の方が女性よりNAD+が高いことを示した。さらに、ヒトのNAD+ベースラインの100日間にわたる長期安定性を明らかにし、実世界のNAD+を調節する主な行動を特定した。＜引用＞Wang P, Chen M, Hou Y, Luan J, Liu R, Chen L, Hu M, Yu Q. Fingerstick blood assay maps real-world NAD+ disparity across gender and age. Aging Cell. 2023 Aug 28:e13965. doi: 10.1111/acel.13965. Epub ahead of print. PMID: 37641521. 2.Temperature-sensitive hydrogel dressing loaded with nicotinamide mononucleotide accelerating wound healing in diabetic mice要約糖尿病性足潰瘍は、糖尿病の一般的な合併症であり、患者のQOLに大きな影響を与え、医療制度に大きな経済的負担を強いている。しかし、現在使用されている治療法には様々な課題があり、従来から使用されているドレッシング材は機能的な有効性を欠いている。糖尿病の創傷治癒には酸化ストレスが重要な役割を果たしていると考えられている。そのため、抗酸化作用で知られるニコチンアミドモノヌクレオチド（NMN）は創傷治癒プロセスを促進する可能性がある。ここで、プルロニックF127とプルロニックF68に抗菌成分キトサンを混合して感温性複合ハイドロゲルを合成した。このハイドロゲルは、安定した構造、適切な固液相変化、ゆるやかな空隙率、徐放性、抗菌性、生体適合性などの良好な特性を示した。In vitroの実験では、NMNを担持した温度感受性ハイドロゲルは、細胞増殖、遊走、血管新生を効果的に促進し、抗酸化活性を示した。糖尿病の厚さの皮膚欠損モデルでは、NMNを負荷した温度感受性ハイドロゲル処理は、コラーゲン合成、血管新生を促進し、血管内皮成長因子とトランスフォーミング成長因子β1の発現を増加させることにより、創傷治癒を有意に促進した。まとめると、NMNを添加した温度感受性ハイドロゲルは、簡便で経済的、効果的かつ安全な方法で糖尿病性創傷の治癒を促進することができ、糖尿病性創傷の治療に応用できる可能性がある。＜引用＞Yue Liang, Min Li, Yuan Tang, Jinlong Yang, Jing Wang, Yuqi Zhu, Huitong Liang, Qinru Lin, Yipen Cheng, Xinyi Yang, Huanzhang Zhu,Biomedicine & Pharmacotherapy,Volume 167,2023,115431,ISSN 0753-3322,https://doi.org/10.1016/j.biopha.2023.115431. 3.NAD+ exhaustion by CD38 upregulation contributes to blood pressure elevation and vascular damage in hypertension要約高血圧は内皮機能障害と動脈硬化を特徴とし、アテローム性動脈硬化性心血管系疾患の病因の一因となっている。ニコチンアミドアデニンジヌクレオチド（NAD+）は、基本的な生物学的過程に関与するすべての生きた細胞に不可欠な補酵素である。しかし、高血圧患者におけるNAD+レベルの変化と血圧（BP）上昇および血管障害との関連はまだ研究されていない。ここでわれわれは、末梢血単核球（PBMC）と大動脈の両方において、高速液体クロマトグラフィー質量分析法（HPLC-MS）で検出されるNAD+レベルの低下が高血圧患者に認められ、血管機能障害と並行していることを報告した。ニコチンアミドモノヌクレオチド（NMN）サプリメントによるNAD+増強療法は、高血圧患者（NCT04903210）およびAngII誘発高血圧マウスにおいて、血圧を低下させ、血管機能障害を改善した。内皮細胞におけるCD38のアップレギュレーションは、NMNのバイオアベイラビリティを低下させることにより、内皮NAD+の枯渇をもたらした。炎症性マクロファージの浸潤と炎症性マクロファージ由来のIL-1β生成の増加は、JAK1-STAT1シグナル伝達経路を活性化することにより、CD38の発現上昇をもたらした。CD38のKO、CD38阻害剤投与、あるいはアデノ随伴ウイルス（AAV）介在による内皮CD38ノックダウンにより、AngII誘発高血圧マウスの血圧が低下し、血管機能障害が改善した。本研究により、内皮CD38の活性化と、それに続くマクロファージ由来IL-1β産生亢進によるNAD+分解の促進が、高血圧における血圧上昇と血管障害の原因であることが初めて示された。NAD+ブースト療法は、高血圧患者の管理のための新しい治療戦略として用いることができる。＜引用＞Qiu Y, Xu S, Chen X, Wu X, Zhou Z, Zhang J, Tu Q, Dong B, Liu Z, He J, Zhang X, Liu S, Su C, Huang H, Xia W, Tao J. NAD+ exhaustion by CD38 upregulation contributes to blood pressure elevation and vascular damage in hypertension. Signal Transduct Target Ther. 2023 Sep 18;8(1):353. doi: 10.1038/s41392-023-01577-3. PMID: 37718359; PMCID: PMC10505611. その他参考文献1.” FDA delays substantive response to NMN petition”, https://www.naturalproductsinsider.com/supplement-regulations/fda-delays-substantive-response-to-nmn-petition

Is the Enzyme eNampt the Future of Health and Longevity?A recent study out of Washington University School of Medicine in St. Louis has uncovered a compelling mechanism that could delay the inevitable and deleterious effects of aging. Previous research has determined that a decline in NAD (nicotinamide adenine dinucleotide) is a major contributor to accelerated aging and chronic disease development. As NAD can reduce the effects of cellular aging, thereby reducing the risk of chronic disease and increasing lifespan, maintaining elevated NAD levels has become a goal of every longevity researcher, biohacker, and anti-aging enthusiast.While there are a couple of well-established ways to increase lifespan through elevated NAD levels in yeast and animal studies, the research team on this study has discovered a new method, using eNAMPT. In this article, we’ll discuss the initial findings, as well as what eNAMPT is and what you need to know about this anti-aging enzyme.NAD+ and NMN: A ReviewIt’s well known that NAD is necessary to fuel every cell in our body; however, levels of NAD decline with age. Also referred to as NAD+ when it’s in its oxidized form, this coenzyme is one we literally cannot live without. Other than fueling cellular metabolism, another crucial action of NAD+ is its ability to activate sirtuins, which are a family of proteins that slow down the aging process — so much so, that they are nicknamed the “longevity genes.” However, you can’t take NAD+ as a supplement, as it would break down in the digestive system before your cells were able to use it effectively. Therefore, its precursors are often used to boost NAD+ levels. The two leading NAD+ precursors are NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside), both of which have been shown to increase NAD+ levels in cells and tissues.What is eNAMPT?Another lesser-known mechanism that boosts NAD+ levels is eNAMPT (extracellular nicotinamide phosphoribosyltransferase), another enzyme that is plentiful in youth but declines throughout the aging process. Researchers at the Washington University School of Medicine found that eNAMPT increases NAD+ levels primarily via its actions on the hypothalamus, which is the body’s control system for many crucial processes, including aging, thirst, hormonal balance, and the circadian rhythm. After being released from adipose tissue, eNAMPT travels to the brain and other tissues, where it internalizes into cells and produces NMN, which can then be converted into NAD+. Note that eNAMPT is one version of NAMPT; the other form is iNAMPT, indicating it is intracellular, while eNAMPT is extracellular. Both forms can synthesize NMN and are found in various tissues, including the skeletal muscle, brain, kidney, liver, and adipose tissue.Being extracellular, eNAMPT is carried by extracellular vesicles, or EVs, which are membrane-coated nanoparticles that function to deliver signals and molecules throughout the body. EVs are found circulating in the blood, which is what the researchers in this study used to increase eNAMPT in older mice.The eNAMPT StudyThe study, which was published in June 2019 in Cell Metabolism, aimed to determine if supplementing older mice with EVs containing eNAMPT was able to effectively boost NAD+ levels and improve markers of health and aging. Shin-ichiro Imai, MD, PhD, the research team isolated eNAMPT-containing EVs from the blood of young mice and supplemented them to aging mice. In an additional experiment, the researchers genetically engineered some of the mice to continue producing the higher, youthful levels of NAMPT in their adipose tissue as they aged.Compared to the control mice, the aging mice who received eNAMPT and the genetically engineered mice had overwhelmingly positive results, including improvements in:・Lifespan, which was extended by 16%・NAD+ production in the hypothalamus, hippocampus, pancreas, and retina・Endurance, measured through wheel-running activities・Sleep quality・Vision, through better functioning of photoreceptors in the eyes・Cognitive functioning, through increased NAD+ in the hippocampusInterestingly, there was a difference amongst sexes: Female mice with higher eNAMPT experienced longer lifespans and delayed aging symptoms for longer than male mice. Overall, however, the eNAMPT-supplemented mice were more youthful, energetic, and overall healthier than the control mice. These results are encouraging, as declines in energy, vision, and cognition are increasingly common age-related symptoms. Restoring these dysfunctions through the upregulation of eNAMPT could result in a healthier aging process.Longevity and eNAMPT Both forms of NAMPT are necessary components of the NAD salvage pathway, an internal recycling program that produces NAD+ from unused forms of niacinamide (also known as nicotinamide or NAM), including NMN and NR. After the body uses a molecule of NAD+, the leftover component is NAM. The NAD salvage pathway reuses it to create more NAD+ and is dependent on the activity of NAMPT. Thus, NAMPT is thought to be the enzyme responsible for controlling NAD+ levels in the body. Maintaining eNAMPT expression is linked to increased longevity and improved health outcomes. Because the hypothalamus is partially controlled by eNAMPT, a decline in eNAMPT levels may lead to hypothalamic dysfunction, which accelerates the aging process.As eNAMPT levels decrease, NAD+ would also diminish, leading to the underactivation of sirtuins, the longevity-regulating proteins.How to Upregulate eNAMPTSimilar to NAD+, there are no supplements of eNAMPT. However, there are a few ways to activate and upregulate the production of both forms of NAMPT. Although NMN does not convert into eNAMPT, NMN does directly enter cells and convert into NAD+. Through the NAD salvage pathway, any unused components of the NAD+ molecule could be recycled, thus continuing the feedback loop and providing additional fuel to maintain the production of NAD+.In some research, resveratrol and anthocyanidins have been shown to increase NAMPT levels, both of which are found in red grape skins. Anthocyanidins are polyphenols that function as antioxidants and are found in plants with red, blue, or purple pigments.In addition to supplements, some lifestyle interventions that can increase eNAMPT. Fasting or caloric restriction can upregulate eNAMPT, as well as sirtuin function and mitochondrial efficiency. Exercise has also been found to increase eNAMPT expression in the skeletal muscle. Key TakeawayA recent study discovered that the enzyme eNAMPT could effectively increase NAD+ levels in mice; NAD+ contributes to health and longevity when its levels are maintained throughout the aging process. In the study, aging mice who received blood with eNAMPT from young mice saw significant improvements in lifespan, cognition, endurance, vision, and sleep quality.Although no eNAMPT supplement exists, fasting, exercise, and resveratrol supplementation may boost levels naturally.

Nicotinamide mononucleotide (NMN) has been a front-running supplement in the anti-aging world due to its ability to convert to nicotinamide adenine dinucleotide (NAD+), a key component that activates a group of enzymes called sirtuins. Dubbed the “longevity genes,” sirtuins can help reverse DNA damage and reduce inflammation, both of which are major contributing factors to overall health degradation due to NAD+ depletion as we age. Another set of enzymes that require NAD+ to be activated are DNA-repairing genes called poly (ADP-ribose) polymerases (PARPs). Without adequate NAD+ levels, genes like sirtuins and PARPs can’t efficiently express themselves. This leads down a rough road that most people accept as the imminent phenomena of “getting older.”But what if getting older didn’t need to be so rough? It seems plausible that we can slow the aging clock if we simply boost our NAD+ levels by taking its precursor, NMN. However, a question is being raised by the longevity community as to whether NMN supplementation may work best when combined with methylation support.Let’s take a closer look at methylation, ways to support this vital biological process of the body, and maximize your NMN supplementation.What is Methylation?Methylation is a fundamental biochemical process in which CH3 (one carbon atom and three hydrogen atoms) is transferred from one molecule to another. This process is responsible for many of our body’s most important functions, such as:・Forming neurotransmitter・Producing free radical scavenging antioxidants・Clearing histamine・Cell division・Cellular energy production・Metabolism・DNA expression (epigenetics)We have a “methyl pool,” a storage center of sorts, containing CH3 methyl groups that we draw upon whenever transfers need to be made for these biochemical processes. If we have enough methyl groups stored in the pool, methylating typically isn’t a problem. However, there are reasons why methylating may pose a challenge for some people or change throughout one’s lifespan. Before exploring NMN supplementation and methylation, here are some common causes of decreased methylation.1. MTHFR VariantsMethylenetetrahydrofolate reductase (MTHFR) is a gene with common mutations that can cause high levels of homocysteine in the blood and low folate levels. Two main MTHFR variants — heterozygous and homozygous — are found worldwide spanning many ethnicities, although some variants seem to affect certain people more than others. Up to 40% of the population may have one or both genetic mutations. However, having an MTHFR mutation does not mean you will display symptoms of a disease or require treatment. Oftentimes, supplementing with methylated B vitamins or other methyl donors, such as TMG, is all that is necessary to support methylation.2. Aging and Epigenetics Methylation of DNA plays a crucial role in epigenetics — the expression of DNA. Methylation does not change the DNA sequencing itself, but rather it switches on and off different sequences of your genetic material when needed. Our methylation ability and subsequent DNA expression declines with age. Though we have a lot to learn about genetics and aging, changes in DNA expression may be linked to disease-related biomarkers, which may contribute to age-related diseases like cancer, osteoarthritis, and neurodegenerative conditions, suggests a study in Rejuvenation Research.NMN Supplementation and Methylation SupportThe ultimate goal of supplementing with NMN is to facilitate the conversion of NAD+ in our cells, thereby activating sirtuin genes and promoting longevity. This action is a part of the salvage pathway that involves the creation of nicotinamide (NAM). When the NAM compound is formed, it also needs to be expelled as a part of this natural pathway. To do this, NAM is methylated into N-methylnicotinamide, which is a metabolite found in our urine. When taken as a supplement, NMN may require the use of methyl groups to create and excrete N-methylnicotinamide. Currently, there is no evidence suggesting NMN’s natural methylation of NAM depletes our methyl pool. Even so, safeguarding against depletion and supporting methylation may be a proactive step to augmenting your NMN intake.How do top anti-aging experts suggest supporting this valuable methyl pool? By adding additional methyl donors to it. At the top of the list — trimethylglycine (TMG). Using TMG to Replenish the Methyl PoolTMG, an amino acid known as betaine, has three methyl groups attached to each molecule of glycine and operates along a pathway similar to B12, a crucial methyl donor. Methyl donors can replenish the methyl groups to support healthy methylation. After experimenting with methyl B-12 and methylfolate for methyl donation, anti-aging guru David Sinclair, Ph.D., switched to TMG as a singular methyl donor — purely as a preventative measure to protect against potential methylation depletion by way of NMN supplementation. “As a precaution, I take trimethylglycine so that I continue to give my body a source of methyl groups,” says Sinclair in an interview with Joseph Mercola, DO. “I don’t see any downside. It’s not an expensive molecule. The upside is that I’m preventing my body from being drained of methyl groups.”If you're currently taking NMN or thinking about starting, consider pairing it with TMG as an added support for methylation. Other methyl donors that may be useful include methylated B6, B12, and folate. Side Effect and ContraindicationsTMG is generally well-tolerated, but side effects such as mild digestive upset or headaches may occur in some people. Primary contraindications are for pregnant or breast-feeding individuals. Talk with your doctor if you have questions or concerns regarding the use of TMG as a part of your supplement protocol. The Bottom LineUltimately, supporting your body’s ability to maintain an adequate methyl pool by supplementing with TMG is worth considering as a precautionary measure. Taking the best NMN supplements along with a methyl donor such as TMG offers the most protection by aiding numerous body processes that require methylation — especially activation of longevity-promoting and reparative genes like sirtuins and PARPs. 

There is an irreversible and unavoidable aspect of reproductive aging that begins when a female reaches her late 30s. As women are now waiting longer to start families, this biological race against time is one of the main contributors to the increasing rates of infertility worldwide.Although we can't stop the years from going by, new research in mice has found that there may be a way to mitigate some of the effects of female reproductive aging and increase fertility as we reach the years approaching 40 and beyond.The Stats on InfertilityApproximately 12% of women in the United States in their reproductive years have trouble getting pregnant or maintaining a pregnancy, reports the Centers for Disease Control and Prevention (CDC). Additionally, one in four couples has been affected by infertility worldwide, suggests finding from the World Health Organization (WHO).After reaching age 35, the likelihood of having infertility struggles jumps to one out of every three women. With statistics like these, it's no wonder that women and couples are looking for solutions to help increase fertility. However, advancing maternal age isn't the only reason behind the rise in infertility rates. Given that the female reproductive system is made up of the ovaries, fallopian tubes, and uterus, dysfunction, or disorders in any of them could contribute to reduced fertility. Other factors that can impact fertility include:・Obesity・Exposure to endocrine disruptors (like BPA in plastics)・Polycystic ovarian syndrome・Endometriosis・Hypothyroidism・Other underlying medical conditionsPlus, it's important to mention that men also play a crucial role in fertility; 20-30% of infertility cases can be linked back to issues with the male reproductive systems as well.Although there are options for those struggling with infertility, like assisted reproductive technologies that include in vitro fertilization (IVF), these treatments can be costly, invasive, pose a risk, and don't necessarily have a high success rate, especially as women age.However, there may be a new option on the horizon to help increase fertility. Emerging research has found that a low supplemental dose of nicotinamide mononucleotide (NMN) was able to restore fertility in aging female mice. NMN is a precursor to NAD+, a crucial coenzyme needed for healthy aging, DNA repair, and metabolism.As NAD+ levels decline with age, so does the quality and number of oocytes, which is the technical name for egg cells before they fully mature into eggs. Oocytes are not self-renewing cells - the amount a woman has at birth will be the highest number she ever has. Due to this finite number of cells that decrease year after year, a woman's fertility is largely based on both the number and the quality of oocytes she has left. While there's no way to increase the number of oocytes, we can improve the quality and functioning of the ones remaining.Based on this, the researchers behind this new study, published in the February 2020 issue of Cell Reports, hypothesized that boosting NAD+ in the oocytes of mice through supplemental NMN may be a low-risk and non-invasive method to increase fertility.What Did the Researchers Find?In this study, the researchers tested several different ways in which NMN could be used to improve fertility or oocyte quality, both of which begin to decline at around eight months of age in mice. Let's take a look at the three most important results that were reported in Cell Reports:1. NMN supplementation increased NAD+ in oocytes.When comparing mice between four and five weeks old to 12-month old mice, the older mice had reduced levels of NADPH in their oocytes, as is to be expected with increasing age. NADPH, a required cofactor for anabolic reactions, is the phosphorylated form of NAD+ (meaning it has a phosphate group attached). The researchers measured this form rather than NAD+ due to bioanalytical challenges of measuring NAD+ in oocytes; nonetheless, the function of both NAD+ and NADPH are very similar - both decline as we (and mice) age. After the 12-month old female mice received water that was treated with NMN at 2 g/L for four weeks, levels of NADPH in their oocytes did increase significantly, indicating that NMN was able to restore the age-related decline in NAD+ seen in the female reproductive system.2. The low dose demonstrated a greater impact on fertility than the high doses.The most interesting outcomes of the study resulted when the researchers gave 13-month old mice two different doses of NMN for four weeks. At 13 months, these mice are very near the end of what's considered their "reproductive years."The low-dose group received 0.5 g/L of NMN-treated water, while the higher-dose group received 2 g/L of NMN in their water. After introducing male mice for breeding, the low-dose group saw significant increases in the number of live births, as well as reductions in the time it took to get pregnant. In contrast, the higher-dose group did not see the same benefits of increased fertility.3. NMN supplementation improved IVF outcomes.Lastly, the researchers also looked at how the oocytes of aged female mice responded to IVF when receiving NMN treatment. After the 12-month-old mice received 2 g/L NMN in water for four weeks, their oocytes had larger diameters - oocytes with smaller diameters are linked to worse outcomes after IVF. When the oocytes of the mice received IVF plus NMN-water for two, seven, 14, or 28 days, a longer treatment of NMN led to improved inner cell mass size, which is linked to improved fertility outcomes after IVF.Similarly, IVF was performed using in vivo oocytes from 12-month-old or 4-week-old female mice, and the embryos were then cultured with or without NMN. After supplementation with NMN, the embryos from the oocytes of the older mice had improved blastocyst formation, but the younger mice did not see similar benefits. This improvement in embryo development solely in the aging mice suggests that NMN supplementation during IVF in younger years may not provide the same therapeutic benefits, likely because NAD+ levels have not yet declined.The Caveats to ConsiderWhile this study does provide encouraging and hopeful results for improving fertility, there are a couple of important points to consider when interpreting the research.Less is MoreThese results of the study suggest that while a larger dose of NMN did benefit oocyte quality by increasing NAD+ levels, it did not actually improve fertility and birth outcomes in the same way the lower dose did.This could be due to an upper limit of NMN tolerability or an increase in nicotinamide, a degradation product of NMN that inhibits sirtuins, which are a family of NAD+-dependent proteins that regulate cellular health and promote healthy aging. Although nicotinamide (the amide form of vitamin B3) does have anti-inflammatory and neuroprotective benefits, it may also increase oxidation when consumed or produced in excess. If NMN was consumed in excess of what is needed, then nicotinamide would be produced as a byproduct in excess as well.In regards to the current study, although the fertility benefits were not seen in the higher dose group, it's important to note that no adverse effects were observed either. Moreover, the aging mice in this study did not have to take NMN long before seeing benefits: 50% of the mice on the low dose of NMN achieved pregnancy by the third week of supplementation, indicating that favorable fertility outcomes may be achieved in a short amount of time.But Humans are Not MiceYes, we know that humans are not mice, and mice are not humans. We can't automatically extrapolate data from mouse studies and assume that they will apply to humans - especially a specific subset of humans like reproductively-aging females.But there are several reasons that mice have been used in medical research for decades. Perhaps surprisingly, humans and mice have very similar genomes, genetics, anatomy, and physiology, which make comparing results a bit more useful. In regards to this study, mice have very similar reproductive systems to humans, albeit a shorter gestation period. Mice also have much shorter lifespans than humans, allowing us to study disease development and longevity more easily, as one mouse year equates to approximately 30 human years.Again, although we can't directly apply these results to us, as humans, the researchers of this study acknowledge that this may be a clinically relevant treatment for infertility by improving outcomes of both natural fertility and IVF.A low dose of NMN may be an appropriate and simple solution to helping the millions of women worldwide who want to get pregnant yet have been struggling in their fertility journey for too long. As always, further research - especially in human clinical trials - is warranted before anything can be said definitively. Nonetheless, the risk of taking a low dose NMN supplement is low, and the benefits to fertility may be high.Your Takeaway: Can NMN Increase Fertility?・In reproductively aging mice, a low dose of NMN was able to increase birth rates and reduce the time to pregnancy more than a higher dose of NMN・The higher dose of NMN was able to restore the age-related decline in NAD+ levels and oocyte quality of aging female mice, as well as improve outcomes of IVF in cultured media・In the future, we may see that low-dose NMN supplementation could be a non-invasive and low-risk way to increase fertility or allow for pregnancies at an older age to remain viable, compared to the invasive and expensive IVF treatment・Research on this topic in humans is needed before any definitive claims can be made about the impact of NMN supplementation on improving or increasing fertility outcomes