Human skin map provides clues on how to stop hair loss

Study reveals how hair follicles are formed in the womb, offering hope for those with alopecia and even baldness

Changing growth media on skin organoids, laboratory work at the Wellcome Sanger Institute. Photo: Wellcome Sanger Institute

Scientists have cracked the code of how human skin is formed in the womb, which they say offers clues on how to treat autoimmune conditions that cause hair loss.

The insights could be used to create new hair follicles for regenerative medicine, such as for skin transplants for burn victims, or those with scarring alopecia or even baldness. The research, led by the UK's Wellcome Sanger Institute and Newcastle University, used single cell sequencing and advanced genomics techniques to map how skin and hair follicles are formed.

In the study, the team created a "mini organ" of skin in a dish with the ability to grow hair, known as an organoid. The results showed how immune cells, known as macrophages, play an important role in skin repair and provide protection from infection.

Skin provides a protective barrier, regulates our body temperature and can regenerate itself. However, researchers say previous research has been difficult as animal models have important differences. Skin develops in the sterile environment of the womb, with all hair follicles formed before birth, a time when skin also has the unique ability to heal without scarring.

Dr Elena Winheim, co-first author from the Wellcome Sanger Institute, said that the prenatal skin atlas provides the first molecular "recipe" for making human skin and uncovered how human hair follicles are formed before birth. "These insights have amazing clinical potential and could be used in regenerative medicine, when offering skin and hair transplants, such as for burn victims or those with scarring alopecia.”

The study, released in the journal Nature, is part of the Human Cell Atlas, an ambitious global project to map cells to better understand human health and help treat serious diseases. The team used samples of prenatal skin tissue, which they broke down to look at individual cells in suspension, as well as cells in place within the tissue.

There were important differences between the lab-grown skin organoids and foetal skin, with the skin organoid model more closely resembling prenatal skin than that of adults. By adding these immune macrophages to the organoid, they discovered the macrophages promoted the formation of blood vessels and helped protect the skin from infection.

Professor Muzlifah Haniffa, co-lead author and interim head of cellular genetics at the Wellcome Sanger Institute, said: “Our prenatal human skin atlas and organoid model provide the research community with freely available tools to study congenital skin diseases and explore regenerative medicine possibilities. We are making exciting strides towards creating the Human Cell Atlas, understanding the biological steps of how humans are built, and investigating what goes wrong in disease.”

The prenatal human skin atlas will also be used to identify in which cells the genes are active, or expressed, that are known to cause congenital hair and skin disorders, such as blistering disorders and scaly skin.