Dr. Charles J. Doillon & Clement Beaumont

 

Controversy has persisted for some time now over the very existence of an area in the hair follicle termed the bulge. Based on new research surrounding the relationship between the bulge and the bulb and by adapting certain techniques, electrolysis treatments may become more effective with less re growth.

 

The existence of the bulge has been scientifically demonstrated and advanced research has provided new insight on the hair follicle regeneration process over the course of a hair growth cycle. Based on this new data, studies were undertaken in a research centre in Quebec in order to observe microscopic lesions on human follicles following electrolysis.

 

The hair follicle undergoes repeated cycles of growth periods (anagen), regression (catagen), and rest (telogen) throughout our life.

 

Along the cycle, a specific area has been identified – termed the bulge, situated close to the sebaceous glands, at the limit between a permanent hair (upper portion) and transient hair (lower portion), and close to the insertion of the arrector pili muscle to the hair follicle.

 

Recently, the bulge has been the focus of advanced studies by scientific experts, since it was believed to host the stem cells and progenitor cells of the epidermis and skin appendages (hair follicle, sebaceous and sudoriferous glands). These cells were found to occur in the outer root sheath within the bulge area.

 

During the follicle growth cycle, the stimulation of stem cells in the bulge leads to the migration and differentiation of progenitor cells toward the epidermis, the sebaceous gland, and specifically towards the hair bulb. They differentiate into a variety of epidermal cells, and form the cells of the bulb during the onset of the newly-formed anagen follicle. These cells extend down into hair-follicle matrix cells during the descent of the newly formed bulb. The bulge therefore plays a role in the life cycle of the hair follicle, when conditions are suitable.

 

Demonstrating this was made possible by using genetically engineered rodents in which a fluorescent green probe is introduced into the genetic material of most cells and then transferred by hair follicle transplantation into non-fluorescent animals. It was observed that fluorescent cells were concentrated in the bulge area during telogen and early anagen phases. Then, in the late anagen phase, the fluorescence was found concentrated in the bulb.

 

The stem cells of the bulge region are normally quiescent throughout the catagen, telogen and most of the anagen phase, but proliferate briefly at anagen onset. We can see from this the pluripotent character of these stem cells emerging from the bulge.

 

In the bulge, the progenitor cells migrate at the onset of the anagen phase and their proliferation is intensely stimulated (the highest proliferation rate of any mammalian tissue). The bulge most likely controls the life cycle of their hair follicle. However, this phenomenon requires the presence of connective tissue cells (mesenchymal cells in the dermis near the hair follicle) and the formation of capillaries or micro vessels by endothelial cells (angiogenesis). These two types of external cells set off the reproduction of progenitor cells and their differentiation into specialized cells to form the new bulb, regenerating the lower follicle at the onset of a new follicular cycle in adults.

 

Based on this new insight of hair follicle development, we should logically target two areas of the hair follicle: the bulb and the bulge. But there is a problem.

 

Stem cells at rest in the bulge area are more heat-resistant than progenitor cells and are therefore harder to destroy. It would be more appropriate to target migrating progenitor cells (moving down the outer root sheath) located between the bulge and the bulb, as well progenitor cells located in the bulb itself (in the inner sheath). The reproduction and differentiation of these cells is very active in these skin surface, thereby increasing the risk of superficial epidermis burns.

 

For the other phases of the hair cycle, the application of this new data appears to differ. Thermolysis applied to a hair follicle in the telogen phase will directly target the stem cells and progenitor cells, but may require a greater amount of energy (considering their resistance to heat) which can be provided by an insulated probe (heat concentration at the tip). It is difficult to determine if a follicle in the catagen phase would be easy to destroy however, given the presence of the two types of cells: those in the catabolic state (which will be destroyed since they cannot withstand heat and the stem cells at rest in the bulge area (which will be heat resistant).

 

Is it still difficult to predict with any certainty if a hair follicle will regenerate or not after treatment. But thanks to this new data and ongoing research, we are now better able to understand what can be modified to improve electrolysis treatments, and these latest results already represent an exceptional breakthrough in terms of insertion techniques.

  Dr. Doillon has received scientific and medical awards, research grants and is an author and co-author of several scientific publications.  Clement Beaumont is President of Dectro International.  www.hairroute.com