What is the theory behind stem cells therapy for acne scars?

Skin concerns such as altered skin texture, scarring, photo-aging & wrinkles can be largely eliminated by increasing the individual’s own stem cells. Repair from wounding is much more complex than just activating stem cells to repair damaged tissue (scars).

We probably have 10 to 20 years to go before stem cell harvesting gives reproducible results. In the past 6 years, there have been significant breakthroughs in the way we understand ASC or adipose tissue stem cells. We now know that fat tissue contains millions of stem cells, about 20 to 50 fold more per volume than bone marrow.

These stem cells are termed pluripotent stems, in theory, they can differentiate to form fibroblasts. These cells produce collagen & elastin.  Additionally, vascular tissue can be formed by endothelial cells. This cascade of regeneration can, in theory, fill in the holes of acne scars (atrophic scar tissue).

Cytokines, growth factors & other nutrients can be transferred within the harvested fat. These compounds can aid in wound remodeling & scar revision.

The current thinking (as of 2020) is that harvesting, processing & injecting autologous fat (from the same individual) for adipose stems, is different to fat transfer from liposuction. In the context of acne scar revision, the aim of autologous transfer include-

1. Volumetric filling of atrophic tissue. This means a buffer or spacer to fill in the holes of atrophic acne scars. In most cases of significant atrophy there is fat loss, hence fat transfer or grafting can be effective. See the section on fat transfer for more information.
2. Stem cell harvesting for pluripotent cells to remodel scar tissue. This harvesting technique is different from normal grafting as tissue has to be handled in a different manner. This fat is processed to nano fat (devoid largely of adipocytes), but rich in stem cells & growth factors. Other techniques include collagenase processing of harvested fat to yield a higher concentration of stem cells.
3. This is then added to the mixture of harvested macro & micro fat, to form an enriched mixture of fat cells & stem cells. This mix is then injected into atrophic areas. This form of stem cell transfer can address adipose poor volumetric changes (fat cell injection) as well as dermal atrophy (lack of collagen, elastin & hyaluronic acid). Fat transfer itself is not ‘stem cell therapy’, you need a hyper concentration of adipose derived stems before the term ‘ stem cell therapy’ is given. This is science, not a marketing term.

The problem with both fat transfer & autologous stem cell therapy is that the results are less predictable than dermal fillers. Undoubtedly the current state of knowledge yields much better results compared to when I first did fat transfer 12 years ago. The fact remains that even with meticulous processing, fat resorption rates of up to 65% can be seen. Additionally there have been a paucity of good studies beyond 1-2 years in the context of longevity.

Regardless of resorption rates, stem cell & adipose tissue transplantation still has a role in the management of moderate to severe atrophic scars. The reasoning behind this is that in some patients the volume of filler may exceed over 15 MLS. Costs play a big factor in the management of clinically significant atrophic scars

It is important to understand that scar revision largely relies on your own immune system to remodel scar tissue. If you can not remodel tissue, procedures like stem cell & adipose tissue can assist your immune system to repair scars. In those people who struggle with tissue remodelling, the only viable option is dermal fillers.

Everyone wants a permanent solution, including dermatologist & plastic surgeons. Our aim is to treat scars & then discharge patients. The fact remains that your results are largely reliant on your immune status. This can not be controlled by physicians.

What is PRP & is it the same as stem cell therapy?

PRP is a super easy procedure of taking your own blood, spinning it down (less than 10 minutes) then either sprinkling the solution on the wounds left from microneedling (or laser). In some cases, it is injected into your skin. The role of PRP is controversial. PRP has better evidence in the context of hair growth & joint therapy.

PRP does not contain stem cells, as it stands for platelet-rich plasma. PRP contains growth factors derived from platelets with a typical hyper-concentration of between 4.5 to 6.0 X.

I do not routinely offer PRP as I believe that it has only marginal effects on healing times & no added benefit in the context of revision of atrophy. I do believe that fat transfer gives better & more predictable results than PRP. I also know of the case reports of adding PRP to fat grafts for˜boosted results. Once again the level of good evidence for this technique is lacking.

If you feel inclined to opt for PRP with stems, let me know, as I do not routinely perform this procedure nowadays. (I used PRP for nearly every case of scar revision from 2014 to 2016 with the under and over technique. I do believe that heal is ever so slightly faster with PRP but the end results are not superior. Happy to discuss.)