Category Archives: Karl Koehler

Hair-Bearing Skin Generated from Pluripotent Stem Cells

Blog readers keep giving me breaking news faster than Google Alerts, and I am appreciative. This time, thanks to “Del”, even if his input has forced me to write two posts in one day. Update: The podcast for this news is here.

Pluripotent Stem Cells and Hair Growth

Yesterday a very important study was published in Nature Magazine. It is titled “Hair-bearing human skin generated entirely from pluripotent stem cells”. The scientists behind this research took 6 years to complete and publish their work.

The study has numerous co-authors from a few medical centers and universities based in the US. The lead author is Dr. Jiyoon Lee, while the correspondence author is Dr. Karl Koehler. The latter works at Boston Children’s Hospital as well as Harvard Medical School. Moreover, Dr. Koehler’s lab has its own site, on which he published a post about these findings.

Dr. Karl Koehler via Twitter

Pluripotent Stem Cells to Grow Hair
Pluripotent Stem Cells to Grow Hair. From Dr. Karl Koehler’s Twitter feed.

From Skin Organoids to Hair

In this latest research, undifferentiated human stem cells were successfully coaxed into developing skin-like organoids in vitro. When these human-derived structures were grafted onto immuno-compromised bald mice, the rodents produced robust (albeit shorter length) hair.

Note that in 2015, Dr. Alexey Terskikh and his team used pluripotent stem cells from humans to create dermal papilla type cells. These were then injected into hairless mice and grew hair.

Pluripotent Stem Cells Hair Growth
Pluripotent Stem Cells and Hair Growth — Nature Magazine.

In this new work, the scientists generated near-complete skin organoids first that ultimately resulted in pigmented hair. The skin cells grew in a sphere and were “fed” with various chemicals and growth factors (such as BMP4 and FGF2) for 4-5 months. Both the dermis and epidermis skin layers were grown successfully.

If this work goes through successful clinical trials, it will essentially mean a cure for hair loss. Nevertheless, the global media has largely ignored this research, with the UK’s Mirror being a notable exception. And as always, the Daily Mail too.

Cotsarelis Rises Again

Prolific blog commentator “MJones”‘ favorite hair loss researcher and fellow Alexander the Great progeny Dr. George Cotsarelis has been missing in action of late. However, this new research is so significant, that Dr. Cotsarelis and Dr. Leo Wang wrote a detailed article summarizing it in Nature Magazine.

Per the two doctors, this study represents a major step towards a cure for baldness in humans. They are confident that this research will eventually see its promise realized. This technique makes it possible to produce human hair without having to take any donor hair from the human.

Moreover, individuals who have major wounds, scars and genetic skin diseases will all benefit from revolutionary new treatments based on this research. That is if it comes to clinic of course.

In these times of pandemics, protests and riots, it is great to see Dr. Cotsarelis’ still unabated optimism. Ironically, for “MJones”, the glass has always been half empty.

Further reading: An excellent 2019 paper summarizing tissue engineering strategies for human hair follicle regeneration.