Introduction: When performing hair transplantation procedures, it is of the foremost importance to try to obtain the maximum survival rate possible of transplanted micrografts. We present an in-vitro model to test hair graft survival and growth after various surgical procedures.
Objective: The aim of our studies were: to evaluate the effects of preserving micrografts, for five hours, in an enriched storage medium in order to enhance the survival rate of hair micrografts; to test the benefits provided by cold-storing hair grafts; to quantify the survival and growth rates of "plucked" human hair follicles; to compare the growth rates of follicular units, conventional, and skeletonized micrografts maintained in culture for 10 days, to quantify the survival and growth rates of bisected human hair follicles.
Methods: A total of 1020 human anagen hair follicles was obtained from 50 male patients. Follicles were thus randomly assigned to one of the following groups: Group A (control; n = 100 follicles), conventional micrografts cultured as dissected; Group B (experimental; n = 100 follicles), conventional micrografts preserved (before culture) for five hours in a storage medium containing adenosine triphosphate-magnesium chloride and deferoxamine mesylate; Group C (control; n = 120 follicles), conventional micrografts preserved (before culture) for five hours in saline at room temperature; Group D (experimental; n = 120 follicles), conventional micrografts preserved (before culture) for 5 hours at 1¢XC; Group E (experimental; n = 60 follicles), "plucked" hair follicles; Group F (experimental; n = 60 follicles), follicular units; Group G (experimental; n = 60 follicles) skeletonized micrografts; Group H (experimental; n = 200 follicles), lower-half follicles, (inferior half of follicles transversely transected, parallel to the epidermal surface and immediately below the bulge area); and Group I (experimental; n = 200 follicles), upper-half follicles, (superior half of follicles transversely transected, parallel to the epidermal surface and immediately below the bulge area). Hair follicles from all the groups were then cultured for 10 days. All the studies were performed maintaining the hair follicles in 500 ƒÝl of Williams medium E with supplements as follows: 1% fetal calf serum, 10 ƒÝg/ml transferrin, 10 ƒÝg/ml insulin, 10 ng/ml sodium selenite, 10 ng/ml hydrocortisone, 100 units/ml penicillin, 100 ƒÝg/ml streptomycin, 2.5 ƒÝg/ml fungizone. Follicles were maintained free floating in individual wells of 24-well multiwell plates in an atmosphere of 37¢XC, 5% CO2, 95% air, and 100% humidity.
Results: A statistically significant difference was found between the survival rate of follicles from experimental Group B (98%) and control Group A (87%). No statistically significant differences were found between the survival and growth rates of follicles from Group C (survival rate = 88%, growth rate 2.68 mm) and Group D (survival rate = 88%, growth rate = 2.54 mm). Most of the "plucked" follicles, follicular units and skeletonized micrografts grew and retained their morphology for the entire 10-day period of culture. A statistically significant difference was found between the growth rate of Group E ("plucked" hair follicles; mean 10-day shaft growth = 2.36 mm) and Group F (follicular units; mean 10-day shaft growth = 2.23 mm) as compared to Group A (control). No statistically significant differences were found between the growth rate of follicles from Group G (skeletonized micrografts) and Group A (control). No statistically significant differences were found between the growth rates of control follicles and of lower-half follicles (Group H), whereas a statistically significant difference was found between the growth rate of follicles from the two above-mentioned Groups and the growth rate of the "upper-half" follicles (Group I; mean 10-day growth rate = 1.07 mm).
Conclusions: According to our data, the described method is, in our opinion, an useful adjunct in order to quantitatively evaluate the effects of various procedures in the field of hair transplantation surgery.