A Dream Or Reality?
For many years it has been the dream of hair restoration professionals and patients to create more than one hair from a single hair. Many studies have been undertaken over the years to bisect a single hair follicle at various levels in the hope that the two halves would grow more than one hair. All studies to date involved bisecting hairs in the horizontal plane. The various trials to date resulted in limited growth from the bisected halves. In all studies it is uncommon to achieve growth from both halves and often uncommon to achieve growth from either half.
Hairs are comprised of both an ectodermal and mesodermal component. In the embryological development hairs begin as an invagination of ectodermal cells that are influenced by mesodermal cells. Studies have attempted to isolate the interaction point of the two embryological stem cells by varying the bisection point. The studies have bisected hairs at the upper third of the follicle, the middle of the follicle, and at the lower third of the follicle. More recently Gho has described a bisection, which we believe is lower at the critical line of auber or at the matrix of the hair cell.
A photo is included to show the three regions of the hair shaft. The upper 1/3rd is called the infundibulum. The middle 1/3rd is called the isthmus, and the lower third is called the bulb. Some studies involving mice have suggested that the stem cells reside at the bulge region of the hair shaft, which is also considered the point of attachment for the arrector pili muscle. Human studies do not confirm the studies in mice. Human studies point more toward a location at the dermal sheath, which is located just below the matrix cells of the hair bulb. Here lies the presumed interaction point between cells of ectodermal origin and mesodermal origin. This is the presumed basis for the success that Gho has seen with hair multiplication. It is believed that he bisects the hair at this point so that the bisected points contain cells of both embryological origins.
Gho offers a tremendous advantage over other hair multiplication studies. He leaves a portion of the hair in the donor region and removes the other half of the bisected hair. This is a challenging effort on his part since the follicular group or follicular unit must be carefully dissected into the subcutaneous fat and gently lifted toward the surface without severing the attachments of the nerves, arteries, an other support tissues adherent to the base of the follicle. The complexity of the follicle can be seen elsewhere in our website where it is detailed by confocal microscopy courtesy of Dr. Erickson. Here you can see the attachments of the arteries and nerves. We have tried this means of bisecting the follicle at the base, but find it exceedingly difficult. We are not quite sure what to cut the follicle with. Under a microscope at high power, 50 to 75X, the bulb looks huge and easy to separate. At standard surgical microscope powers of 6 to 10X, the bulb is much smaller. In addition, there are no specific instruments we know of designed to cut a structure precisely at the critical line of auber. Therefore, we prefer to wait until we speak with Dr. Gho in October 2003 before attempting this method further.
No study we are aware of has looked at bisecting hairs in the longitudinal plane. This is the basis for our hair multiplication trial. While our method will not result in the retention of a donor follicle that can later be re-harvested again, we believe that our method will allow us the ability to create 4 or more hairs from a single follicle. If the theory works, it may allow 10 or 20 hairs to be gleaned from a single follicle. Therefore, we believe the study has merit and should proceed.
Our method allows all the structures of both ectodermal and mesodermal origin to be transplanted intact. This allows the greatest chance for success.
The basis of our trial is to carefully dissect the outer root sheath out of the skin after plucking the hair from the follicular structure. The free dermal sheath is then dissected into two portions along its longitudinal axis. The two structures contain inner root sheath, outer root sheath, matrix, dermal sheath, and hopefully fragments of the dermal papilla. The two bisected halves are then planted flush into non-hair bearing skin. For our purposes, we are testing the growth on the human wrist since typically very little hair grows here. We can later extract the hairs individually if the patient desires us to remove them using our follicular isolation technique or FIT.