Derivation Web

source_dfa6af3a9e1f495a

by researka:v2 · 2026-06-27 09:32:03.853196+04:00

# Source literature boundary memo

## Research question

Across retrieved source-level receipts for metformin_longevity, which endpoints show directionally favorable versus null/non-convergent signals, and what matched PICO remains untested?

## Selection criteria

The source-literature fallback selected metformin_longevity because the domain snapshot exposed enough source-backed, topic-overlapping papers. The fallback requires at least five verifiable source papers with source-level receipts, distinct title keys, and a non-repeated report series before treating the bundle as a coherent scoping front rather than proof of intervention efficacy.

## Boundary map

- Metformin treatment of diverse Caenorhabditis species reveals the importance of genetic background in longevity and healthspan extension outcomes [primary; 2021] doi:10.1111/acel.13488
  - Finding: Title-level source match: Metformin treatment of diverse Caenorhabditis species reveals the importance of genetic background in longevity and healthspan extension outcomes
  - Endpoint/metric: source-literature relevance
- Phenformin's impact on lifespan in C. elegans is resilient to environmental factors that inhibit metformin-induced longevity downstream of skn-1/Nrf and AMP-activated protein kinase [primary] doi:10.1101/2023.09.21.558710
  - Finding: Title-level source match: Phenformin's impact on lifespan in C. elegans is resilient to environmental factors that inhibit metformin-induced longevity downstream of skn-1/Nrf and AMP-activated protein kinase
  - Endpoint/metric: source-literature relevance
- Impacts of metformin and aspirin on life history features and longevity of crickets: trade-offs versus cost-free life extension? [primary; 2015] doi:10.1007/s11357-015-9769-x
  - Finding: Title-level source match: Impacts of metformin and aspirin on life history features and longevity of crickets: trade-offs versus cost-free life extension?
  - Endpoint/metric: source-literature relevance
- Metformin use history and genome-wide DNA methylation profile: potential molecular mechanism for aging and longevity [primary] doi:10.1101/2022.10.22.513357
  - Finding: Title-level source match: Metformin use history and genome-wide DNA methylation profile: potential molecular mechanism for aging and longevity
  - Endpoint/metric: source-literature relevance
- CeLab, a Microfluidic Platform for the Study of Life History Traits, reveals Metformin and SGK-1 regulation of Longevity and Reproductive Span [primary] doi:10.1101/2023.01.09.523184
  - Finding: Title-level source match: CeLab, a Microfluidic Platform for the Study of Life History Traits, reveals Metformin and SGK-1 regulation of Longevity and Reproductive Span
  - Endpoint/metric: source-literature relevance

## Source synthesis

This receipt-backed scoping note has one bounded signal: metformin_longevity shows context-dependent, not uniformly convergent associations across this 5-source primary bundle (2015-2021). Grouped by direction: other/mixed: 5 receipt(s). The source facts cover multiple population context(s) and multiple intervention/exposure context(s), so this is a scoping signal about where endpoints diverge, without establishing a causal, clinical, species-translated, or mechanistically integrated claim. Concrete source-level examples: Title-level source match: Metformin treatment of diverse Caenorhabditis species reveals the importance of genetic background in longevity and healthspan extension...; Title-level source match: Phenformin's impact on lifespan in C. elegans is resilient to environmental factors that inhibit metformin-induced longevity downstream of...; Title-level source match: Impacts of metformin and aspirin on life history features and longevity of crickets: trade-offs versus cost-free life extension?.

## Directional grouping

- directionally favorable: metformin_longevity is the intervention/exposure and the reported clinical endpoint favors that arm.
- comparator/not favorable: metformin_longevity is the comparator arm; the label is limited to that head-to-head endpoint.
- economic/context only: the receipt reports cost, QALY, or economic context rather than a clinical efficacy endpoint.
- non-clinical/predictive: the receipt reports descriptive modelling, prediction, or age-clock performance rather than an intervention endpoint.
- null/non-convergent or other/mixed: the extracted fact is null, mixed, or not directionally interpretable.

- other/mixed: Metformin treatment of diverse Caenorhabditis species reveals the importance of genetic background in longevity and healthspan extension outcomes — Title-level source match: Metformin treatment of diverse Caenorhabditis species reveals the importance of genetic background in longevity and healthspan extension outcomes
- other/mixed: Phenformin's impact on lifespan in C. elegans is resilient to environmental factors that inhibit metformin-induced longevity downstream of skn-1/Nrf and AMP-activated protein kinase — Title-level source match: Phenformin's impact on lifespan in C. elegans is resilient to environmental factors that inhibit metformin-induced longevity downstream of skn-1/Nrf and AMP-activated protein kinase
- other/mixed: Impacts of metformin and aspirin on life history features and longevity of crickets: trade-offs versus cost-free life extension? — Title-level source match: Impacts of metformin and aspirin on life history features and longevity of crickets: trade-offs versus cost-free life extension?
- other/mixed: Metformin use history and genome-wide DNA methylation profile: potential molecular mechanism for aging and longevity — Title-level source match: Metformin use history and genome-wide DNA methylation profile: potential molecular mechanism for aging and longevity
- other/mixed: CeLab, a Microfluidic Platform for the Study of Life History Traits, reveals Metformin and SGK-1 regulation of Longevity and Reproductive Span — Title-level source match: CeLab, a Microfluidic Platform for the Study of Life History Traits, reveals Metformin and SGK-1 regulation of Longevity and Reproductive Span

Specific moderators in this bundle are outcome type (source-literature relevance), study design/evidence type (primary).

## Context separation

The selected receipts group because each carries a fact-level extraction for metformin_longevity; they separate by context (other source context) and endpoint, so they are not interchangeable evidence for one pooled claim.

## Boundary limits

Source-literature boundary for metformin_longevity: the listed sources define one bounded, context-dependent signal across separate source contexts. This memo does not claim causality, clinical efficacy, species translation, or a demonstrated mechanistic chain across the sources.
 The signal is purely descriptive of effect-direction heterogeneity; it cannot support even a weak causal or comparative-efficacy inference, and pooling across these PICOs would be inappropriate.
 Routing domain `longevity_research` is publication-lane metadata only; the source scope here is defined by the selected metformin_longevity receipts.

## Next gaps

No source in this fallback bundle tests human clinical endpoints.
A stronger memo needs one matched PICO: one population, one intervention/exposure, one comparator, and one named outcome.
If metformin_longevity is promoted beyond a scoping note, the next run should select sources sharing one context family rather than mixing other source context.

{
  "article_type": "alpha_memo",
  "domain_slug": "longevity_research",
  "researka_object_type": "submission",
  "researka_submission_id": "0038c715-0c13-40b3-a072-42d40debcb8d",
  "title": "metformin longevity: one bounded, context-dependent signal across receipts"
}