source · application/json
source_7b5a7a2eeb6a4f73
sha256 416102d18b7b5dbf6c8c35d7c9e413070bae1ab99ceae4b7f28601236b838b20
by researka:v2 · 2026-08-22 21:13:31.270499+04:00
{"contradictions": ["Null findings have a specific role in this evidence model. They do not erase mechanistic plausibility, but they do narrow the set of claims that can be made about effect consistency, target population, and endpoint selection.", "For instance, while one trial reported a trend toward improved NYHA class in heart failure patients [Yu 2025] [bundle:4], other trials in different populations found null effects on functional endpoints, such as mitochondrial respiration and skeletal muscle function in older adults [Connell 2021] [bundle:5] and cognition in long-COVID patients [Wu 2025] [bundle:1] [exact source: https://doi.org/10.1007/s40256-025-00764-7] [exact source: https://doi.org/10.1093/jn/nxab193] [exact source: https://doi.org/10.1016/j.eclinm.2025.103633].", "Null findings have a specific role in this evidence model. They do not erase mechanistic plausibility, but they do narrow the set of claims that can be made about effect consistency, target population, and endpoint selection.", "For instance, while one trial reported a trend toward improved NYHA class in heart failure patients [Yu 2025] [bundle:4], other trials in different populations found null effects on functional endpoints, such as mitochondrial respiration and skeletal muscle function in older adults [Connell 2021] [bundle:5] and cognition in long-COVID patients [Wu 2025] [bundle:1] [exact source: https://doi.org/10.1007/s40256-025-00764-7] [exact source: https://doi.org/10.1093/jn/nxab193] [exact source: https://doi.org/10.1016/j.eclinm.2025.103633].", "The geroscience framework reframes the clinical challenge: rather than developing separate therapies for heart failure, atherosclerosis, and metabolic syndrome, one might target the shared biological substrate of aging itself. NAD+ precursors, including nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), represent a drug class that has moved rapidly from preclinical observation to human supplementation trials. The regulatory pathway for these compounds has been complex; they are often marketed as dietary supplements, which permits consumer access but limits the regulatory oversight and standardized dosing that characterize pharmaceutical development. Another trial demonstrated that a combination of nicotinamide and D-ribose (RiaGev) increased the NAD+ metabolome, with NADP+ rising by 27% compared to placebo after seven days of supplementation [Xue 2022] [bundle:7] [exact source: https://doi.org/10.3390/nu14112219]. These findings confirm that oral precursors can reliably raise circulating NAD+, but the critical question is whether this biochemical elevation translates into clinically meaningful cardiovascular protection.", "A review of the human RCT landscape reveals a striking heterogeneity in study populations, interventions, and endpoints, with very few trials directly assessing cardiovascular outcomes. The most direct cardiovascular evidence comes from a trial in patients with heart failure caused by ischemic cardiomyopathy, where intravenous NAD+ was compared to placebo. This study reported a statistically significant improvement in left ventricular ejection fraction (LVEF) within the NAD+ group at one month, but the between-group comparison for New York Heart Association (NYHA) class improvement showed only a trend (P = 0.088 at one month, P = 0.115 at six months) [Yu 2025] [bundle:4] [exact source: https://doi.org/10.1007/s40256-025-00764-7]. A separate trial in older adults with heart failure found that seven days of intravenous NAD+ injection improved NT-proBNP levels and LVEF values compared to saline, although the differences were not statistically significant [Pei 2024] [bundle:11] [exact source: https://doi.org/10.31083/j.rcm2508297]. Other trials have examined NAD+ precursors in populations with acute kidney injury [Simic 2020 [bundle:3], Pencina 2025 [bundle:12]], long-COVID [Wu 2025] [bundle:1], sudden sensorineural hearing loss [Gao 2025] [bundle:2], and mild cognitive impairment [Roy 2026] [bundle:9], where cardiovascular endpoints were not the primary focus [exact source: https://doi.org/10.1186/s12882-020-02006-1] [exact source: https://doi.org/10.1096/fba.2025-00014] [exact source: https://doi.org/10.1016/j.eclinm.2025.103633] [exact source: https://doi.org/10.1002/lary.70173] [exact source: https://doi.org/10.1002/trc2.70278]. This fragmentation of the evidence base means that any synthesis of cardiovascular effects must draw indirect inferences from trials designed for other purposes.", "Several unresolved questions complicate the interpretation of the existing evidence. First, the mechanism by which elevated NAD+ might improve cardiac function remains poorly defined in humans; proposed pathways include enhanced mitochondrial bioenergetics, reduced oxidative stress, and improved endothelial function, but these are largely extrapolated from preclinical models. Second, the duration of supplementation in most trials is short—often weeks to a few months—raising the question of whether longer-term exposure is necessary for cardiovascular benefit or whether it introduces unforeseen risks. Third, dose-response relationships are unclear; trials have used a wide range of doses, from 250 mg/day of NMN [Katayoshi 2023] [bundle:10] to 1000 mg twice daily of NR [Airhart 2017] [bundle:15], and the optimal dose for cardiovascular protection is unknown [exact source: https://doi.org/10.1038/s41598-023-29787-3] [exact source: https://doi.org/10.1371/journal.pone.0186459]. Fourth, population specificity is a concern, as the most promising cardiovascular signals come from patients with established heart failure [Yu 2025 [bundle:4], Pei 2024 [bundle:11]], while trials in healthier populations have not demonstrated clear cardiovascular benefits [Martens 2018] [bundle:16] [exact source: https://doi.org/10.1007/s40256-025-00764-7] [exact source: https://doi.org/10.31083/j.rcm2508297] [exact source: https://doi.org/10.1038/s41467-018-03421-7]. Finally, the trade-off between potential benefits and safety in vulnerable populations, such as those with acute kidney injury, requires careful evaluation [Simic 2020 [bundle:3], Pencina 2025 [bundle:12]] [exact source: https://doi.org/10.1186/s12882-020-02006-1] [exact source: https://doi.org/10.1096/fba.2025-00014].", "The current evidence base presents significant cross-outcome tensions that must be explicitly addressed. For instance, while one trial reported a trend toward improved NYHA class in heart failure patients [Yu 2025] [bundle:4], other trials in different populations found null effects on functional endpoints, such as mitochondrial respiration and skeletal muscle function in older adults [Connell 2021] [bundle:5] and cognition in long-COVID patients [Wu 2025] [bundle:1] [exact source: https://doi.org/10.1007/s40256-025-00764-7] [exact source: https://doi.org/10.1093/jn/nxab193] [exact source: https://doi.org/10.1016/j.eclinm.2025.103633]. This synthesis will separate mechanistic evidence from clinical evidence, acknowledging that biochemical changes (for example, increased NAD+ levels) do not automatically confer clinical benefit. The structured evidence weighting will prioritize direct human RCT data with cardiovascular endpoints, while clearly delineating the indirect evidence from trials focused on other outcomes. The goal is to provide a transparent assessment of where the evidence is strong, where it is suggestive, and where significant gaps remain, particularly regarding the long-term cardiovascular effects of NAD+ precursor supplementation in diverse human populations.", "The evidence profile indicates that the case for NAD+ precursors as cardiovascular therapeutics is currently incomplete. Mechanistic plausibility is supported by the central role of NAD+ in cellular metabolism and the consistent ability of oral precursors to raise circulating levels [Airhart 2017 [bundle:15], Xue 2022 [bundle:7]] [exact source: https://doi.org/10.1371/journal.pone.0186459] [exact source: https://doi.org/10.3390/nu14112219]. However, the human RCT evidence is sparse and mixed. Direct cardiovascular trials are limited to small studies in heart failure populations with short follow-up and non-significant or trend-level between-group differences [Yu 2025 [bundle:4], Pei 2024 [bundle:11]] [exact source: https://doi.org/10.1007/s40256-025-00764-7] [exact source: https://doi.org/10.31083/j.rcm2508297]. The broader trial landscape includes studies in non-cardiovascular populations where cardiovascular endpoints were not assessed or were secondary [Wu 2025 [bundle:1], Gao 2025 [bundle:2], Roy 2026 [bundle:9]] [exact source: https://doi.org/10.1016/j.eclinm.2025.103633] [exact source: https://doi.org/10.1002/lary.70173] [exact source: https://doi.org/10.1002/trc2.70278]. Furthermore, some trials in relevant populations, such as older adults, have failed to show functional benefits on muscle or mitochondrial endpoints [Connell 2021] [bundle:5] [exact source: https://doi.org/10.1093/jn/nxab193]. The boundary conditions for any potential benefit—including optimal dose, duration, patient selection, and the specific cardiovascular outcomes that might respond—remain to be established. This synthesis aims to map these boundaries by systematically evaluating the available evidence, highlighting both the promises and the significant uncertainties that currently define the field.", "| NAD+ Cardiovascular Effects / Contextual Adjacent Evidence | n=7; claims=174 | positive=0, negative=0, null=1, mixed=0, unclear=6 (n=7) | 7 direct | limited corpus depth in this outcome class |", "| NAD+ Cardiovascular Effects / Muscle Function | n=4; claims=100 | positive=0, negative=1, null=1, mixed=0, unclear=2 (n=4) | 4 direct | limited corpus depth in this outcome class |", "| NAD+ Cardiovascular Effects / Animal/Preclinical Context | n=2; claims=27 | positive=0, negative=0, null=0, mixed=0, unclear=2 (n=2) | 2 mechanistic | limited corpus depth in this outcome class |", "| NAD+ Cardiovascular Effects / Safety and Comorbidity | n=2; claims=52 | positive=0, negative=0, null=0, mixed=1, unclear=1 (n=2) | 2 direct | limited corpus depth in this outcome class |", "| NAD+ Cardiovascular Effects / Cardiometabolic | n=1; claims=13 | positive=0, negative=1, null=0, mixed=0, unclear=0 (n=1) | 1 direct | single-source slice; hypothesis-generating |", "| NAD+ Cardiovascular Effects / Dosing and Pharmacokinetics | n=1; claims=29 | positive=0, negative=0, null=0, mixed=0, unclear=1 (n=1) | 1 direct | single-source slice; hypothesis-generating |", "Thesis:** Across 17 curated reference papers, the evidence base for NAD+ shows a context-dependent profile. Negative signals appear in: muscle function, cardiometabolic. Null findings dominate: Contextual Adjacent Evidence, muscle function. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. The NAD+ broad aging-related case as currently constituted is incomplete: mechanistic plausibility coexists with mixed or sparse human-RCT evidence, and the boundary conditions remain to be established. This position is bounded by the included sources and does not imply clinical efficacy beyond the evidence profile."], "limitations": ["This is an agent-assisted evidence map, not a PRISMA-complete systematic review or clinical guideline.", "It is not PROSPERO-registered and should not be read as medical advice.", "Public sidecars expose citation traces and extraction status; empty fields mean not extracted, not assumed absent."], "publication_id": "9be40a10-b14d-4e4a-afff-f058a818c80b", "screening": {"excluded": 0, "exclusion_reasons": ["No PRISMA full-text exclusion-stage filter was applied."], "flow": ["identified", "screened", "excluded_with_reasons", "included"], "identified": 17, "included": 17, "included_or_retained": 17, "screened": 17, "wording": "17 candidate receipts retained after source retrieval, deduplication, and topic filtering. This is an evidence-map screening trace, not a PRISMA full-text exclusion audit."}}
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