Promotional effect of platelet-rich plasma on hair follicle reconstitution in vivo.

BACKGROUND: Platelet-rich plasma (PRP) containing various growth factors has attracted attention in various medical fields. PRP has recently been used during hair transplantation to increase hair density. OBJECTIVE: To investigate the effects of PRP on hair follicle (HF) reconstitution. METHODS AND MATERIALS: Freshly isolated epidermal cells and cultured dermal papilla cells (DPCs) were mixed with various concentrations of activated PRP and transferred to a grafting chamber that was implanted onto the dorsal skin of nude mice. The chambers were removed 1 week after grafting, and HF formation was monitored for 4 weeks. RESULTS: We observed a significant difference (p < .05) in the number of newly formed follicles in the area of reconstituted skin (344 ± 27 with 10% PRP vs 288 ± 35 without PRP). PRP also shortened the time of hair formation significantly; the first hairs were observed in 18 ± 1 days using 10% PRP, versus 20 ± 1 days without PRP. CONCLUSION: A considerable effect of PRP on the time of hair formation and the yield of HF reconstitution was observed in this study. Considering the limited evidence available to judge its efficacy, further studies are required to investigate the mechanism of action of PRP.

[Hair follicle regeneration by injection of follicular cells].

OBJECTIVE: To explore the mechanisms of hair follicle regeneration by injection of follicular cells isolated from murine skin. METHODS: Epidermis 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. RESULTS: 2 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. CONCLUSIONS: Follicular 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.

[Subcutaneous implantation of embryonic skin cells to construct a model of hair development in nude mice].

OBJECTIVE: To observe the hair development after subcutaneous implantation of embryonic skin cells in nude mice, and construct a model of hair development. METHODS: Dermal and epidermal cells isolated from embryonic mouse skin were mixed at a given ratio and injected subcutaneously in nude mice, and hair formation after the implantation was observed under a microscope. RESULTS: Formation of the hair follicles and fibers under the skin of the recipient nude mice and emergence of the hair shaft were observed microscopically. CONCLUSION: Embryonic skin cells be used to construct a complete model of hair development after implantation in vivo.

[Effects of different parts of the follicle-unit grafts subjected to controlled injury].

OBJECTIVE: To study the shaft elongation and morphological changes of follicle-unit (FUs) grafts subjected to controlled injury in different parts. METHODS: Human FUs were isolated by microdissection under a dissecting microscope. The single hair of anagen FUs were randomly divided into A, B and C groups, and A and B groups were subjected to controlled injury with microsurgery imposed to the dermal papilla and the bulge of FUs, respectively, with C as the control group without any treatment. HE staining was used to detect the histological changes of the cells, and organ culture for 10 days was conducted to observe the morphological changes and elongation of FUs. RESULTS: There were no histological or morphological changes in A, B and C groups. The average elongation of hair shaft was 1.293-/+0.245, 2.116-/+0.423 and 2.235-/+0.379 mm, respectively. There were significant differences between groups A and B (P<0.05) and between groups A and C (P<0.05). No significant difference was found between groups B and C (P>0.05). CONCLUSION: Damage of the dermal papilla should be avoided in hair transplantation surgery.

[Effective isolation and culture of the outer root sheath bulge cells, dermal sheath cells and dermal papilla cells derived from human hair follicle].

OBJECTIVE: To establish an effective method for isolating and culturing outer root sheath (ORS) bulge cells, dermal sheath cells (DSCs) and dermal papilla cells (DPCs) derived from human hair follicle. METHODS: Small scalp specimens were incubated in the presence of dispase at 37 degrees celsius; for 2 h, the hair shafts with ORS embedded in the dermal sheath (DS) were extracted under dissecting microscope, and the ORS tissue were inoculated onto Petri dish. The specimens were transected at the interface between the dermis and subcutaneous tissue. The portions of DS and DP (linked with and enclosed by DS) embedded in the adipose tissue were pulled out and incubated with collagenase at 37 degrees celsius; for 6-8 h, and the DP and DSCs were isolated by repeated low-speed centrifugation and cultured respectively on Petri dishes. The cultured ORS bulge cells were identified by immunohistochemistry with K19 antibody and DPCs and DSCs by immunohistochemistry with alpha-actin antibody. RESULTS: Purified ORS bulge cells, DSCs and DPCs could be harvested from the same human hair follicle. CONCLUSION: This new method allows efficient, rapid, and simultaneous isolation and culture of ORS bulge cells, DSCs and DPCs.

[Hair follicle cell mixture forms hair follicle-like structures after subcutaneous implantation in nude mice].

OBJECTIVE: To observe the hair follicle regeneration after subcutaneous implantation of hair follicle cell mixture in nude mice. METHODS: The hair papilla cells, dermal sheath cells, outer root sheath and fibroblasts of human scalp were mixed with the hair follicle epithelial cells and implanted subcutaneously in nude mice to observe the regeneration of the hair follicle. RESULTS AND CONCLUSION: Formation of intact hair follicle-like structures was observed in the skin sections of the recipient nude mice, suggesting the feasibility of this approach for hair follicle regeneration in vivo.

[Isolation and in vitro culture of follicular papilla cells from rat vibrissae].

OBJECTIVE: To establish a simple method for isolating and culturing follicular papilla cells from rat vibrissae. METHODS: The intact follicles were obtained and digested in 0.2% collagenase I with agitation on a rotary stirrer at 100 r/min at 37 degrees C; for 3 h. The suspension was centrifuged at 300 r/min and the papilla cells were collected and suspended in DMEM for cell culture. The adhesion efficiency of the dermal papilla cells was evaluated and compared with that of the cells obtained by microdissection. RESULTS AND CONCLUSION: The described procedure allowed efficient and rapid isolation of the dermal papilla cells from rat vibrissae and ensured improved adhesion of the dermal papillae and outgrowth of the cells with reduced labor and risk of contamination. The cells obtained with this procedure were positive for alpha-smooth muscle actin staining.