Exosomes is a broad term. Sounds fancy, and there is some true beneficial science there, but there is likely a lot of of stuff that doesn’t do much. I have spent a great amount of time trying to figure out the difference.
This was from PRS Global Open, June 2023. “The Potential Role of Exosomes in Aesthetic Plastic Surgery: A Review of Current Literature.”
I loved this study. It gave a good summary of exosomes, describing how they are derived from vegetables, bone marrow, placenta, fat, or umbilical cords. They talked about the broad uses touted by these exosomes: from what you would expect- skin, scars, hair restoration- to helping with fat graft survival. Prices vary. None of these are FDA approved yet. This is still a wild west of medicine, but there is science in here. We just need to figure it out.
Bad scars can be widened, depressed, elevated, keloid, pigmented, depigmented. So the needed treatment can vary. We don’t know exactly how exosomes work on scars, but there are a multitude of studies looking at its effect on acne pitting, and fresher scars (ie surgical scars). There are hypothesis on how they work. Again, remember “exosomes” is a broad term. The exact how much, which one, how is it given, timing on this cascade of scarring- we need to study it all.
The science behind how exosomes work varies based on the stage of wound healing. The current thought processes:
- STAGE 1. Immediate healing is focused on blood clots forming to stop bleeding. Cytokines and growth factors that recruit inflammatory cells to the area.
- STAGE 2. This is the inflammatory phase. It gets rid of cellular debris and prevents infection. It is in this phase you transition to the proliferative healing phase with keratinocytes, fibroblasts, and new blood vessel formation. Exosomes may help calm the inflammatory response which prevents secondary injury in this phase.
- STAGE 3. In the proliferative phase fibroblasts lay down a matrix of collagen III. Keratinocytes migrate across the wound surface to close the defect. Exosomes increase proliferation and migration of fibroblasts, collagen III deposition, and angiogenesis.
- STAGE 4: Remodeling phase. Collagen I replaces collagen III, with cross-linking maturation and flattening of scars. Exosomes effects here are the most talked about:
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- Exosomes reduce excessive cross-linking
- increased ratios of collagen III: collagen I, MMPs:TIMPs, and TGF-β3:TGF-β1.
- Exosomes also inhibit myofibroblast differentiation via several miRNAs’ actions.
- There are theories on how the different exosomes work: ASC-exos indicates adipose-derived exosomes; MSC-exos, mesenchymal stem cell-derived exosomes; EPSC-exos, epidermal stem cell-derived exosomes; PDGF, platelet-derived growth factor; VEGF, vascular endothelial growth factor; EGF, epidermal growth factor; FGF, fibroblast growth factor; KGF, keratinocyte growth factor.
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My thoughts?
There is something here. A different study I read looked at the ideal timing of microneedling to improve scars, and to my surprise, found it to be around 6-7 weeks out. I am curious exactly where this is on this healing cascade.
I think with all of these things, prevention is key. It makes sense to try to treat a fresh scar, rather than fix an old, mature scar. But the question then comes what is the ideal timing? An immediate scar is just trying to pull itself together. I think that is likely too soon. And old mature scar? There isn’t a lot of movement. That is pretty established. So the answer is in between.
Given I do not know, I am deferring to the microneedling study which tried different timing in the scar healing cascade and settled on around 6 weeks.
I am offering this to my surgical patients if they desire. Age zero exosomes used with microneedling (which has been show in itself to help with scarring and is an excellent delivery system creating microchannels to help the exosomes penetrate into the scar), done at 6 weeks. This is new science. But given the scientific articles I have seen published, my hope is that we can try to biohack scarring better, to find that right combination of enough inflammation and remodeling to create better scars. Too little inflammation and healing, scars widen and don’t heal well, too much and we get keloids, pigmentation, and elevated scars.
Stay tuned.