Category Archives: Hair Follicle Stem Cells

Dr. Pietro Gentile, Hair Follicle Stem Cells and PRP

Over the past few years, I have heard a lot about Dr. Pietro Gentile of Italy and his unique work in the hair loss field. His website and his Instagram have some interesting content. However, both are lacking relative to the higher quality of his numerous research papers.

Dr. Pietro Gentile and PRP

I originally learnt about Dr. Gentile via his collaboration with Dr. John Cole and Chiara Insalaco. In 2017, the three of them authored a paper comparing non-activated PRP versus activated PRP.

In my detailed post on the effectiveness of PRP for hair loss, I listed around 40 studies at the bottom. Of that total, 5 were authored by Dr. Gentile. On his website, the doctor has several pages devoted to PRP for hair loss and PRP for facial cosmetic treatments.

Hair Follicle Stem Cells

Micrograft Stem Cell Transplant Hair Growth Before After -- Pietro Gentile
Micrograft Stem Cell Hair Transplant Before and After in a 38-year old Female. Copyright © 2020 Pietro Gentile et al.

More interestingly, Dr. Pietro Gentile has in recent years published a number of papers on stem cells and hair growth. Most recently, in January 2020, he authored a paper titled “Autologous Micrografts from Scalp Tissue“. The conclusion was that micrografts containing autologous human hair follicle mesenchymal stem cells (HF-MSCs) could represent a safe and viable hair loss treatment.

The autologous micrografts of HFSCs were prepared using the doctor’s proprietary “Gentile Protocol”. Instead of harvesting hair follicle grafts like in a hair transplant, this process entails harvesting scalp tissue and associated hair follicle stem cells. I think that this tissue extraction can also be from outside the typical permanent hair donor zone. Dr. Gentile published the outline of his hair follicle stem cell isolation technique in an earlier paper from 2017.

Autologous Micrografts of Hair Follicle Stem Cells
Autologous Micrograft Injections of Hair Follicle Stem Cells (HFSCs) in a 41-year old Male with Androgenetic Alopecia. Before and After (58 Weeks). Copyright © 2020 Pietro Gentile et al.

Other Findings

in 2019, Dr. Gentile published a study on Adipose Tissue-Derived Hair Follicle Stem Cells (HD-AFSCs) improving hair growth and density. Make sure to read my past posts on adipose stem cells and hair growth. The doctor has also published a number of papers in the past on stromal vascular fraction, especially in regenerative plastic surgery and scar reduction applications.

In 2020, Dr. Gentile and his team found that a combination PRP + Microneedling + Laser treatment protocol led to great hair growth results. However, hard to tell which of the three made the most impact.

COL17A1 Damage: Hair Thinning and Turning into Skin

Update: A blog reader from Brazil sent me something very interesting yesterday. Apparently, there was a study published less than two months ago that concluded that chronic inflammation was turning eye cells into skin cells! Read more here.


Today, the prestigious Science Magazine published two new studies related to hair loss and stem cells. They also had a brief summary on the link between aging, stem cells and alopecia, authored by Dr. Cheng-Ming Chuong from USC who I have mentioned on this blog before.

Update: Below news now also covered in many other sources, including Time, Guardian and the Daily Mail.

Collagen 17A1 and Shrinking Stem Cells

The first study from Japan is titled “Hair follicle aging is driven by transepidermal elimination of stem cells via COL17A1 proteolysis.” For non-scientists, the contents of that study are not very easy to understand without spending some time googling the various technical terms listed in there.

However, an easier to understand article analyzing the above study’s findings concludes that “One reason your hair is thinning is because some of it turns into skin.” The study also discusses shedding of epidermal keratinocytes from the skin surface. A lot of people complain about dandruff, itching and dermatitis throughout their scalp while they are slowly balding, and I have had those problems many times in the past decade.

Nizoral and sunshine have both helped me tackle those problems, but I can never seem to go for more than a few days without at least some itching and skin shedding. Note that a Japanese article on this study actually mentions the word “dandruff” in there when you translate to English.

The study authors found that hair follicles in women over age 55 were smaller and with lower levels of the protein Collagen 17A1 (see more on COL17A1 here). Age-related DNA damage triggers the destruction COL17A1. This in turn triggers the transformation into “epidermal keratinocytes”, aka skin.

It is good to see a study that is devoted to female hair loss sufferers. Moreover, one of the lead authors of the study is also a female by the name of Dr. Emi Nishimura. The researchers also engineered mice to lack the COL17A1 gene, and then found that these mice had no follicle-generating cells.

Foxc1 Activates Nfatc1 and BMP signaling

The second study is titled “Foxc1 reinforces quiescence in self-renewing hair follicle stem cells.” Foxc1 (also known as Forkhead box C1) belongs to the Forkhead family of proteins and transcription factors.

Per these scientists from the University of Colorado, Foxc1 regulates the hair growth cycle, and perhaps manipulating this in future could prevent balding. There is also a strong link between Foxc1, Nfatc1 and bone morphogenetic protein (BMP) signaling.