OBJECTIVE: To review recent advances in the application of hair transplantation in wound healing and scar repair in special areas. METHODS: An extensive review of the literature on the application of hair transplantation in wound healing and scar repair in special areas was conducted, focusing on cellular functions, molecular mechanisms, and clinical applications. RESULTS: Hair transplantation has been shown to effectively promote wound healing and scar repair in special areas. The underlying mechanisms are complex, but current understanding emphasizes a strong association with hair follicle-associated stem cells (including epidermal stem cells, dermal papilla cells, dermal sheath cells, etc). CONCLUSION The application of hair transplantation in wound healing and scar repair in special areas remains in its early stages. Further investigation into its mechanisms of action is essential, and randomized controlled trials are needed to establish its efficacy.
Humans ; Wound Healing/physiology* ; Cicatrix/therapy* ; Hair/transplantation* ; Hair Follicle/transplantation*

Full-thickness scalp burns secondary to hair coloring are rare; however, such defects can be large and complex reconstruction of hair-bearing tissue may be necessary. Many skin-stretching devices that use gradual traction have been applied to take advantage of the viscoelastic properties of the skin. A 21-year-old female patient was seen with a burn defect on her occipital scalp leading to exposed subcutaneous tissue after chemical application of hair coloring in a salon. The dimensions of the wound were 10 cm×5 cm, and a skin graft or flap would have been necessary to close the defect. Two long transfixing K-wires (1.4 mm) and paired 3-wire threads (23 gauge), which are readily available in most hospitals, were applied over a period of 12 days for trichophytic closure of the defect. The remaining scalp scars after primary trichophytic closure with this skin-stretching method were refined with hair follicle transplantation. This skin-stretching method is simple to apply and valuable for helping to close problematic areas of skin shortage that would otherwise require more complicated procedures. This case shows a relatively unknown complication of hair coloring and its treatment.
Burns ; Burns, Chemical ; Cicatrix ; Female ; Hair Color ; Hair Follicle ; Hair ; Humans ; Methods ; Scalp ; Skin ; Subcutaneous Tissue ; Traction ; Transplantation ; Transplants ; Wound Healing ; Wounds and Injuries ; Young Adult

BACKGROUND: Little is known concerning hair diameter variation within the safe donor area for hair transplantation surgery. Thicker or thinner hair may be needed, depending on the recipient area, hairline design, and the purpose of surgery. METHODS: Twenty-seven patients (7 men and 20 women; mean age, 28 years; range, 20–47 years) were included in this study. The midoccipital point was used as the reference point on the horizontal plane at the upper border of the helical rim. The target area width was 15 cm (7.5 cm to the right and left of the reference point) and the height was 8 cm (2 cm above and 6 cm below the reference point). The study area was divided horizontally into 3 5-cm sections (A, B, C) and vertically into 4 2-cm sections (1–4), creating a total of 12 zones. Ten anagen hairs were randomly obtained from each zone and their diameters were measured. RESULTS: Hair diameter in the 4 vertical sections varied significantly, gradually decreasing from sections 1 (superior) to 4 (inferior) in all 3 horizontal sections (A, B, and C). CONCLUSIONS: Our results suggest that sections 1 and 2 of the occipital safe donor area would be useful for obtaining thicker hair, such as in procedures to treat male- and female-pattern hair loss, whereas hair from zones 3 and 4 could be useful for transplantation surgery requiring thinner hair, such as eyebrows, eyelashes, and female hairline correction. Our results may be clinically valuable for planning hair transplant surgery and choosing the optimal donor region.
Eyebrows ; Eyelashes ; Female ; Hair Follicle ; Hair* ; Humans ; Male ; Tissue Donors* ; Transplant Donor Site ; Transplantation

OBJECTIVETo investigate the therapeutic effect of soft tissue expansion combined with follicular unit extraction( FUE) for burn cicatricial bald.

METHODS48 patients with burn cicatricial bald (> 25 cm2) were treated in three stages. The expanders were implanted on the first stage. After expansion for 8 weeks, the expanders were taken out and local flaps were transferred. One year later, follicular unit extraction( FUE) was applied on the bald area.

RESULTS48 cases were followed up for 5 years with satisfactory cosmetic results. The VAS assessment of satisfaction on hair appearance after three-staged surgery was 8.2 ± 2.1.

CONCLUSIONSSoft tissue expansion combined with FUE has a reliable effect for burn cicatricial bald.

Alopecia ; etiology ; surgery ; Burns ; complications ; surgery ; Female ; Hair ; transplantation ; Hair Follicle ; transplantation ; Humans ; Male ; Surgical Flaps ; transplantation ; Tissue Expansion ; methods ; Tissue Expansion Devices

OBJECTIVETo investigate the effect of embryonic dermal signal on the hair-inductive capacity of neonatal mice dermal cells which have been amplified in vitro.

METHODSEmbryonic mice dermal cells of embryonic day 14 were added to a chamber on the back of nude mice with neonatal mice dermal cells which had been amplified in vitro for 3 days and freshly isolated neonatal mice epidermal cells. The hair regeneration was compared between the groups with or without embryonic mice dermal cells. Meanwhile, chambers with following cells respectively were constructed as controls: embryonic mice dermal cells + neonatal mice epidermal cells; freshly isolated neonatal mice dermal cells + neonatal mice epidermal cells; amplified neonatal mice dermal cells only; embryonic mice dermal cells only; freshly isolated neonatal mice dermal cells only; neonatal mice epidermal cells only.

RESULTSThe number of regenerated hairs with the aid of embryonic mice dermal cells (207 +/- 15. 948) was significantly higher than that (67 +/- 8.963) in the group without embryonic mice dermal cells (n = 3, t = 7.653, P = 0.002).

CONCLUSIONEmbryonic dermal signal can enhance the hair-inductive capacity of neonatal mice dermal cells which have been amplified in vitro.

Animals ; Cell Transplantation ; methods ; Cells, Cultured ; Hair ; physiology ; Hair Follicle ; surgery ; Mice ; Mice, Nude ; Reconstructive Surgical Procedures ; Regeneration ; Skin ; cytology ; embryology

OBJECTIVETo explore the mechanisms of hair follicle regeneration by injection of follicular cells isolated from murine skin.

METHODSEpidermis was peeled off from the dermis of 3-5 d C57BL/6J mouse by 0.2% Dispase digestion at 37 degrees C for 2 hours. Dermis was cut into small pieces and digested in 0.2% collagenase at 37 degrees C for 30 minute with low speed stirring to isolate hair follicles from dermis. Hair follicles were collected through filtration, low-speed centrifugation and density gradient centrifugation. Collagenase and trypsin were added to digest hair follicles into dissociated cells which were marked by Dio and injected into the nude mouse skin.

RESULTS2 d after intradermal injection of hair follicle cells, a cyst was formed containing lots of round and elliptical cells and homogeneous eosin stained cell-free tissues. The cyst wall was composed of many spindle shaped fibroblast cells and showed sparsely localized green fluorescence. The contents of the cyst showed bright green fluorescence. 4 d after injection, the skin became slightly thicken with grey appearance, a lots of hair follicles formed with black bulb. 1 weeks after injection, the injection site became black and evaluated with a lots of black hair follicles and hyperproliferation of capillary blood. Newly formed hair follicles showed bright green fluorescence. 3 weeks after injection, a cyst containing lots of black hairs formed in the injection site. Newly formed hair follicles showed positive for Dio. Sebaceous gland can be seen accompanied with hair follicles. 6 weeks after injection, the cyst contained lots of sheded club hair shafts and hair follicles on the stage of anagen. Cultured follicular cells and injection below 1 x 10(5) failed to regenerate hairs. While the regenerated hair follicle was few when the hair follicle cells were injected subcutaneously.

CONCLUSIONSFollicular cells can aggregate spontaneously and develop synergistically into hair follicles with normal growth cycle after implantation. The regeneration depends on the interactions between follicular cells, as well as on the recipient sites and cell numbers.

Alopecia ; surgery ; Animals ; Cell Transplantation ; methods ; Dermis ; cytology ; Epidermis ; cytology ; Hair Follicle ; cytology ; Injections, Intradermal ; Mice ; Mice, Inbred C57BL ; Mice, Nude ; Regeneration ; Skin ; cytology ; Tissue Engineering ; methods

OBJECTIVETo develop a follicular unit-like construct with allogeneic hair, evaluate its histocompatibility and long-term stability after transplantation, and explore the possibility of its clinical application.

METHODSHuman hair and medical polypropylene was processed according to the structure of follicular units and prepared into hair prostheses for transplantation. The histocompatibility of polypropylene and human hair in New Zealand rabbits was observed by HE staining and scanning electron microscope, and the loss rate of the hair was recorded to evaluate the long-term result of transplantation.

RESULTSMild inflammatory cell infiltration around polypropylene and human hair was observed early after the transplantation, accompanied with local epithelial cell proliferation. The prosthesis mimicking the follicular units still showed good histocompatibility one year after the transplantation without degradation of the hair. The loss rate of the hair was averaged (4.1∓4.0)% at one year after the transplantation, and the total appearance of the prosthesis remained satisfactory.

CONCLUSIONAllogeneic human hair and polypropylene in the hair prosthesis show good histocompatibility in rabbits. The prosthesis allows good cosmetic effect after transplantation with low rate of hair loss, demonstrating its potential in clinical application.

Animals ; Biocompatible Materials ; Female ; Hair ; transplantation ; Hair Follicle ; transplantation ; Humans ; Materials Testing ; Polypropylenes ; Rabbits

OBJECTIVETo observe the histocompatibility of a polypropylene matrix implanted subcutaneously for potential hair follicle transplantation in rabbits.

METHODSThe polypropylene matrix for harboring the hair follicles was prepared and implanted subcutaneously at the neck of 5 New Zealand white rabbits by means of hair follicle unit transplantation. At 1 week after the transplantation and then on a monthly basis in the following 6 months, full-thickness skin tissues were sampled at the site of grafting to evaluate the histocompatibility of the matrix material using HE staining and scanning electron microscopy.

RESULTSAt 1 week after implantation of the matrix material, a small number of inflammatory cells and lymphocytic infiltration were observed around the graft, with mild hyperemia in the proliferative capillaries and mild inflammatory responses. In the following 6 months, the inflammatory cells and lymphocytes around the graft decreased obviously or even disappeared, and such graft rejection responses as tissue lysis and necrosis were not observed. A large quantity of collagen fibers were found to encapsulate the polypropylene material.

CONCLUSIONPolypropylene matrix graft has good histocompatibility with the rabbit subcutaneous tissue without producing obvious graft rejection responses, suggesting its feasibility for further experiments of hair follicle transplantation.

Animals ; Biocompatible Materials ; Female ; Hair Follicle ; transplantation ; Implants, Experimental ; Male ; Polypropylenes ; Rabbits

OBJECTIVETo study the effect of the technique of synchronously perforating and transplanting hair follicular-units in the treatment of cicatricial alopecia after burn.

METHODSOne hundred and sixty-six patients with 217 bald scar areas after burn were treated with above-mentioned technique from January 2002 to April 2008. Scalp strips, with conforming the necessity for grafting, were harvested from the occipital or temporal region. A series of follicular-units, each composing 1 - 3 hairs, were dissected from the strips under microscope or magnifying glass. Size-matching micro-slots were made in the scarred recipient area with 16 - 20 G needles to accept the grafts. The prepared follicular-unit was synchronously implanted into the bottom of the micro-slot as the needle being withdrawn. Patients who were not satisfactory with the density of hairs after I stage surgery underwent II stage surgery a half year later. Ten recipient areas with clear boundary in 10 patients were optionally chosen to observe the density of follicular-units and hair amount with naked eyes after I stage surgery. Survived transplanted hairs in above-mentioned 10 areas were counted to calculate hair survival rate at follow-up. Patients' postoperative satisfaction ratings were surveyed with questionnaire.

RESULTSIn one half of the patients, treatment was finished after I stage surgery, the other one half received 2 stages of surgery. The follicular-unit density reached 15 - 25 grafts/cm(2) with 40 - 70 hairs/cm(2) after I stage surgery. All patients were followed up for over 8 months. Grafted hairs grew well in a natural way. 96.5% mean hair survival rate was observed in the 10 recipient areas. From patients who received only I stage surgery, 61 patients (73.5%) were very satisfactory and 22 patients (26.5%) satisfactory with the results. From the other half of patients, 76 patients (91.6%) were very satisfactory and 7 patients (8.4%) satisfactory with the results.

CONCLUSIONSThe technique of perforating and transplanting follicular-unit hair synchronously is safe and effective with less surgery-induced injury and less bleeding. Hairs transplanted on cicatricial alopecia area with this technique grow well with high survival rate.

Adolescent ; Adult ; Aged ; Alopecia ; etiology ; surgery ; Burns ; complications ; Child ; Cicatrix ; complications ; Female ; Hair Follicle ; transplantation ; Humans ; Male ; Middle Aged ; Skin Transplantation ; methods ; Young Adult

OBJECTIVETo establish a convenient and reliable method for inducing hair regeneration by follicular cell implantation for the treatment of alopecia.

METHODSThe human hair follicle stem cells were separated and purified by micromanipulation and magnetic cell sorting, and human scalp dermal papilla cells were isolated by enzyme digestion. The two cells were mixed and implanted subcutaneously in nude mice to observe the regeneration of the hair follicles.

RESULTSFormation of intact hair follicle-like structures was observed in the skin sections of the recipient nude mice.

CONCLUSIONFollicular cell implantation can induce hair follicle-like structures in nude mice, which provides a means for efficient hair regeneration for treatment of hair loss.

Adult ; Alopecia ; surgery ; Animals ; Cells, Cultured ; Coculture Techniques ; Female ; Hair Follicle ; cytology ; growth & development ; transplantation ; Humans ; Male ; Mice ; Mice, Nude ; Middle Aged ; Stem Cell Transplantation ; methods ; Stem Cells ; cytology ; Transplantation, Heterologous ; Young Adult