Extracellular vesicles as possible therapeutic candidates for a wide range of age-related pathologies

Rejuvenation of an old organism was achieved in heterochronic parabiosis experiments, implicating different soluble factors in this effect. Extracellular vesicles (EVs) are the secretory effectors of many cells, including cardiosphere-derived cells (CDCs) with demonstrated anti-senescent effect.

1. To determine the role of EVs (versus other blood fractions) on the rejuvenating effect of the young blood.

2. To evaluate the anti-aging properties of therapeutically administered EVs secreted by young-CDCs in an old organism.

Researchers at Cedars-Sinai Medical Center used neonatal blood fractioned in 4 components (whole blood, serum, EV-depleted serum and purified EVs) to treat old human cardiac stromal cells (CSPCs). CDCs were generated from neonatal rat hearts and the secreted CDC-EVs were purified. CDC-EVs were then tested in naturally-aged rats, using monthly injections over 4-months period. For validation in human samples, pediatric CDC-EVs were tested in aged human CSPCs and progeric fibroblasts. While the purified EVs reproduced the rejuvenating effects of the whole blood, CSPCs treated with EV-depleted serum exhibited the highest degree of senescence. Treatment with young CDC-EVs induce structural and functional improvements in the heart, lungs, skeletal muscle, and kidneys of old rats, while favorably modulating glucose metabolism and anti-senescence pathways. Lifespan was prolonged. EVs secreted by young CDCs exert broad-ranging anti-aging effects in aged rodents and in cellular models of human senescence. This work not only identifies CDC-EVs as possible therapeutic candidates for a wide range of age-related pathologies, but also raises the question of whether EVs function as endogenous modulators of senescence.

Extracellular vesicles are the main carriers of the rejuvenating effects of neonatal serum

Figure 5

(A) Schematic representation of in vitro “heterochronic parabiosis” assay. Cardiac stromal-progenitor cells (CSPCs) obtained from > 55-year old human donors were treated with different fractions of neonatal rat blood: (B) whole blood (including all cells), using transwell membranes; S, serum separated from B by centrifugation; (D), EV-depleted serum obtained from S by 3-h ultracentrifugation; EV, extracellular vesicles purified from S by density gradient protocol. Volumes of each fraction used for treatment of each well were adjusted to ensure an equal volume of serum in B and S, equal protein concentration in S and D, and equal number and concentration of EVs in S and EV. Each fraction was then diluted in serum-free medium and used to treat CSPC for 72 h. Then CPSCs were washed, fixed, and stained for different senescence markers. (B) Total free protein concentration in different blood fractions was measured with the BCA assay. (C) EV concentration in different blood fractions measured with Nanoparticle Tracking Analysis. Distilled water (DW) was used as a negative control. (D) Representative images of CSPCs after priming with different blood fractions and stained for: senescence-associated β-galactosidase (SA-βGal, blue) – upper panel; proliferation and DNA damage markers ki-67 (green) and γH2AX (red), respectively – lower panel. (E) Pooled results of analysis show the highest percentage of senescent cells in CSPCs primed with depleted serum (D) where the vesicles’ concentration is the lowest, and recapitulation of total serum’s (S) effect with the fraction of purified EVs. P-values were estimated with ANOVA. Data presented are means ± s.e.m. Number of replicates per experiment was three.

Grigorian Shamagian L, Rogers RG, Luther K, Angert D, Echavez A, Liu W, Middleton R, Antes T, Valle J, Fourier M, Sanchez L, Jaghatspanyan E, Mariscal J, Zhang R, Marbán E. (2023) Rejuvenating effects of young extracellular vesicles in aged rats and in cellular models of human senescence. Sci Rep 13(1):12240. [article]

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