Hair loss affects millions of people worldwide. Although treatments do exist, these solutions are costly and not always effective. Looking for a more lasting and effective solution, scientists have turned their attention to understanding the molecular mechanisms that regulate hair growth, leading to a new frontier in hair regeneration: dermal exosomes.

When people go bald, hair follicles (the tube-like pores that surround the root and strand of a hair) don’t disappear, they shrink. Herein lies the key to a long-lasting treatment for hair loss.

The hair follicle cycle is divided into three distinct phases: anagen (growth), catagen (regression), and telogen (resting). For individuals suffering from hair loss, the problem often lies in hair follicles remaining in the telogen phase for too long or shrinking over time. This leads to thinning and eventual hair loss. If we could reactivate these follicles, we’d basically have a solution for hair loss — and this is where dermal papilla comes in.

Dermal papilla (DP) cells, found at the base of hair follicles, play a crucial role in regulating the hair growth cycle. They send signals to the surrounding skin cells, prompting the hair follicle to transition from telogen to anagen, allowing new hair to grow. However, as DP cells age or undergo environmental stress, they lose their regenerative capacity.

Researchers found that dermal exosomes — tiny vesicles secreted by dermal papilla cells — could revolutionize hair loss treatment. Led by Shiqi Hu and her team, this research uncovered how exosomes containing specific microRNA regulate a key signaling pathway to promote hair regeneration. These findings offer a promising alternative to traditional hair loss treatments.

Exomes to the rescue

Exosomes are small extracellular vesicles that cells release into their environment, carrying proteins, lipids, and microRNAs that can influence the behavior of nearby cells. In recent years, exosomes have gained attention for their role in cell communication and tissue regeneration.

Hu’s team sought to explore the potential of dermal papilla-derived exosomes in mouse models. They isolated exosomes from DP cells and cultured them in two environments: a standard 2D culture and a 3D spheroid setup. These 3D spheroids replicate a cell’s natural microenvironment more effectively.

They found that the cells in the 3D spheroids were particularly rich in the microRNA that stimulates hair growth. They then assessed how well this treatment works on mice with hair loss.

The results were remarkable. After just 15 days, mice treated with the 3D spheroid cells achieved 90% hair coverage. The team also found that biochemical markers of hair growth all spiked after the treatment. So, this suggests that the exosomes not only promote hair follicle growth locally but also induce a more widespread regenerative response throughout the skin.

If the same findings are also confirmed in humans, it could make hair loss a thing of the past.

A scalable treatment

Hair loss is a complex condition with multiple underlying causes, from hormonal imbalances to genetic predispositions. This makes finding a one-size-fits-all treatment very challenging. However, the discovery of dermal exosomes and their ability to promote hair follicle regeneration offers a promising new approach. It targets the root of the problem: the hair follicle’s ability to transition between growth phases.

While traditional treatments like minoxidil work by increasing blood flow to hair follicles, they don’t address the underlying issues within the follicle itself. Dermal exosomes, by contrast, can directly influence the cellular processes that regulate hair growth, offering a more targeted and potentially more effective solution.

The researchers also highlight the potential to incorporate dermal exosomes into non-invasive delivery systems. Options like microneedle patches or topical sprays would make them accessible to a broader population. Such approaches could revolutionize the way hair loss treatments are administered, offering a more convenient and less painful option compared to current therapies.

But researchers aren’t only thinking about hair loss.

The findings of this suggest broader applications for exosome-based therapies in regenerative medicine. Exosomes are relatively easy to isolate and deliver and can be used to enhance tissue repair in various contexts. So, in the case of hair regeneration, they offer a minimally invasive alternative to more aggressive treatments like hair transplants, which are costly and often limited by the availability of donor hair follicles. In future, we may see gentler and less invasive treatments for more than just hair loss.

The research was published in Science Advances.