Systemic factors in young human serum influence in vitro responses of human skin and bone marrow-derived blood cells in a microphysiological co-culture system.
Level 5 - mechanism / opinion, no new human data
In vitro microphysiological bench study using human cell models
PubMed 40728515 · doi:10.18632/aging.206288
What was done
Researchers developed a microphysiological co-culture system combining a 3D human skin model with a 3D human bone marrow model. They treated the system with young human serum versus aged human serum to assess skin proliferation and biological age via DNA methylation clocks. They further analyzed bone marrow cell population shifts, performed proteomic screening of bone marrow-derived secretions, and tested individual candidate proteins in human skin cell aging assays.
What was found
Young serum improved proliferation and reduced DNA methylation age in skin tissue compared to aged serum, an effect that occurred only in the presence of bone marrow-derived cells. Proteomic profiling identified 55 candidate rejuvenating proteins secreted by bone marrow cells in response to young serum, and 7 of these proteins demonstrated rejuvenating activity when tested individually in skin cell assays. The abstract reports no numerical effect sizes, sample sizes, or p-values.
Why it matters
This study provides an in vitro human microphysiological platform to study heterochronic rejuvenation and indicates that bone marrow-derived cells are necessary intermediaries for blood-borne skin rejuvenation factors.
Limits
The study is entirely in vitro, omitting systemic physiological interactions such as vascular clearance and immune-mediated responses. The abstract omits donor numbers, donor ages, effect sizes, and variance measures, and in vivo efficacy remains unverified.
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