What is the Dermal Papilla?
The dermal papilla is a structural formation located in the uppermost layer of the dermis. It can be found throughout the body, and its primary purpose to hook up the epidermis (the outermost layer of skin) to a blood supply. In terms of hair anatomy, dermal papilla in the scalp provides oxygen and nutrients to the hair follicle itself so that healthy new hairs may grow.
How do Dermal Papilla Provide Nutrients?
The dermal papilla provides nutrition by extending from the dermis into the hair bulb. The hair bulb is a formation at the bottom of the hair follicle itself, and it is the structure responsible for sprouting the hair shaft up the follicle, past the scalp. Once the dermal papilla connects to the hair bulb, the hair may receive oxygen from the blood supply and continue its three phases of growth (anagen, catagen, and telogen). If the DP fails to reach the hair bulb, however, the phases are interrupted, and new hairs will not be able to grow. This only has to happen as little as one time before the hair follicle is rendered permanently useless.
Dermal Papilla and ATP
ATP is the bioorganic process in which oxygen is converted from the bloodstream into usable energy. Almost every area of the body utilizes ATP, even the hair. ATP is what gives hair the energy to grow. One of the major hurdles of hair transplantation is keeping the hair graft alive outside of the body, where it is unable to receive nutrition from the DP.
The Formation of the Dermal Papilla
In order for dermal papilla to form, the following steps must happen beneath the scalp:
- A plate-like structure called a placode forms at the epidermis.
- Fibroblasts (structures which create and regulate proteins) form underneath the placode into what’s known as the dermal condensate.
- A chemical signal from the placode and the dermal condensate causes the follicle to form and extend downward into the dermis, guided by epithelial cells. Epithelial cells are special types of cells that form the lining of body cavities such as the lungs, intestines, and, in this case, hair follicles.
- Some of the epithelial cells (but not all) merge with the dermal condensate to form the DP.
- The DP controls the remaining epithelial cells, and signals for them to turn into other crucial structures as needed, such as the hair shaft and the inner root sheath.
The Dermal Papillae and Dihyrdrotestosterone (DHT)
DHT is a male sex hormone that can cause baldness by gathering in the scalp’s tissue in high amounts. In certain individuals, enough DHT can prevent the dermal papilla from reaching the hair bulb. This causes the follicle to miniaturize and produce thinning hairs. Over time, the follicle will cease to produce hair altogether.
Future Medical Uses for Dermal Papillae Cells
Studies have shown that the dermal papilla cells are sturdy enough to survive a transplant from one area of the scalp to another. When dermal papilla cells are transplanted to the recipient scalp, they can cause new hairs to form. Researchers hope to one day be able to reliably remove the dermal papilla cells from a scalp and use them to clone new donor hair. If this process were perfected, it will provide an endless supply of donor hair for transplantation purposes.