| Background:Hair is the head of hair. It can prevent the head from hot sun in summer and cold in winter, resist minor collision, and help head evaporate sweat, protect your head in many ways; they can also increase the beauty of people. Therefore people who posses a soft, glossy and healthy hair routinely have certain advantages in social activities. Alopecia is a common clinical symptom, it often brings patients with physical and psychological stress, and therefore, alopecia has been the focal attention of people as the development of material civilization and spiritual civilization.The cause of alopecia is complex; it mainly includes mental or physical factor, endogenous testosterone hair loss, drug factor, the factor of food and nutrition metabolism, congenital factor, physical and chemical factor, endocrine disorder factor, the immune system disorder and other reasons flocculation reaction function. In the causes of alopecia, androgentic alopecia (AGA) is the most common one.Drug treatmentAt present, the main drug treatments include hormone regulator and biological response modifier. The former includes androgen blockers and estrogen-mediated agents; the latter includes Minoxidil and so on. The commonly used one is 5a reductase inhibitor: such as proscar can block the testosterone transforming into DHT in the peripheral conversion of testosterone to low the concentration of DHT in the serum and scalp, at last the male hormone will not continue inhibit the growth of hair at the control of 5-a reductase of isenzymes. So it can effectively reverse the course of alopecia, and promote hair re-growth in the alopecia area; Minoxidil is the first one can promote hair regrowth, the mechanism is through regulating the vascular endothelial growth factor mRNA expression in the dermal papilla cells, thereby stimulate the hair follicle growth and prolong the hair follicle growth phase, promote the development of minute hair follicle, it ultimately play a treatment role for alopecia. In addition, some drugs can promote blood circulation, such as anisodamine, dexamethasone, Salvia, and dandruff, shampoo also can treat alopecia, etc. Although the kind of drug treatment of baldness is various, but the effect of treatment is not acceptable, the biggest drawback that it is easily to relapse after drug withdrawal, and some oral medications will bring some complications, such as decreased libido, sexual dysfunction, hirsutism, psychosis.Low-Level Light TherapyLLLT is also known as low level laser therapy, red light therapy, cold laser, biostimulation, and photobiomodulation. This is a new treatment, in 2007 low-level light therapy (LLLT) was approved by the FDA as a treatment for hair loss. The LLLT is monochromatic light. There is a specific wavelength of light that has optimal therapeutic effects, and any level higher or lower than this may not be proficient. This therapeutic window ranges roughly from 600 to less than 1,400 nm, it is close to the absorption spectrum of hemoglobin and water, respectively. Furthermore, respiratory chain components (mainly cytochrome C) have a similar absorption spectrum. Therefore, a low level light therapy can increased tissue temperature, improve cell metabolism, and promote hair growth, most experts agree that LLLT is safe for the treatment of hair loss. But its drawback is that relapse of alopecia after withdraw of phototherapy.Cosmetology TechnologyCosmetology Technology includes wearing wigs, weaving hair, replacement hair. All of these Cosmetology technologies can cover up the bald area, but there still exist some drawbacks. because the wig is made of chemical fiber yarn hair, the stretch and endurance is bad, its appearance is too gloss and bright, the dull visually can be seen at the first glance by others, poor ventilation, feeling irritated, hot usually make the scalp easy to be got allergies, sometimes it damages scalp and hair follicles. The disadvantage of wearing weave is inconvenient to take on and take off, cleaning care must be done at the place where the weave fixed, the fixing way is uncomfortable, also damage the hair follicles around the weaved hair, its life time is short, the flaws can be easily seen by others. The disadvantage of the replacement hair is that the flow of hair is not strong, the hair style is single, the use area is limited, people who with high quality and pursuit the perfect and fashion hair style is difficult to accept this treatment. Therefore, cosmetic treatments can not absolutely address the patients' psychological pressure.Surgery treatmentssurgical technique can be dated back to 1939, when Japan's doctors Okuda used the Punch technique to harvest the occipital composite circular skin tissue with hair and transplanted to burn patient. At last the transplanted hairs successful grew, which can also be called as the first case of hair transplantation.The modern surgical treatment of alopecia technology includes the following methods: flap transfer surgery, scalp tissue expansion, scalp reduction surgery, scalp autologous transplantation and so on. Scalp reduction surgery is simple, the wound tension is very small, but the indication is limited, it is only suitable for the long and narrow pattern baldness lesion. Scalp tissue expansion is a modern surgery with shortcomings such as the treatment period is long, need multiple injections, with many complications , some patients often painful because of the expansion is too large, some patients can not accept it.Transplantation of autologous scalp require high clinical skills and special equipment. But the skin flap is easy to necrotize, so the success rate is extremely low.1959 Oren Reich used the 4mm punch to harvest the hair for the treatment of male pattern hair loss and found the "donor advantages ", namely the occipital scalp hair follicles is not sensitive to androgen. This theory lied on a theoretical basis of Hair transplantation, and then entered the new era of modern hair restoration techniques. The classic hair transplantation employed a large rough hair embryo, resulted in the "straw" like appearance, made patients difficult to accept it. Heading ton found that hair was not evenly distributed, it existed as a units which contain 1 to 3 hairs, each unit had its own relatively independent sebaceous glands, standing hair muscle, vascular plexus around the hair follicles, called as follicular unit. Hair follicle transplantation survival rate can be improved if employ such unit, we also can get a natural appearance. Then hair transplant techniques had been improved by this theory in 90'of last century, hair transplantation employed the natural-based follicular unit, made hair transplant technology became more mature, and generally welcomed by patients with natural and lasting effect. However, patient must have sufficient donor before operation, because patients who with too large and limited donor sites can not achieve the satisfy appearance of hair and density. So, how to solve the apparent shortage of resources of hair follicle becomes a clinical question that need to be resolved in the hair restoration surgery.In a word, we still have not found a practical and satisfactory method of treatment at present. To address the serious shortage of the donation of clinical patients'need. Since 2006, our research group have carried out a series of studies and designed a type of portable wigs (patent number 200620057171)). The portable wigs were expected to solve the serious shortage of patient's self donation for the clinical needs. However, in the preliminary studies, the products were found to have some limitations in clinical application and require further improvement. The current studies are to improve our previous designation and try to develop follicular unit like wigs with allogeneic hair, and also investigate the histocompatibility and long-term stability of wigs after transplantation and explore the possibility of industrial production and clinical application.Part I Designation and production of follicular unit like wigs Method:1,Designation of follicular unit like wigs: The base of graft was square-shaped With a visible barb. The angle between the barb and the base was 20-40°. Human hair was closely surrounded by the polypropylene base. Each graft contains 1-4 hairs. The length of hair can be customized according to patient's need. The length of hair used in current experiments was about 14cm.2,Preparation of hair: Hair from health females was soaked in 75% alcohol for 2 hours, and rinsed with 0.9% NaCl, then immerged in 2% glutaraldehyde for 20 minutes and rinsed many times in 0.9% NaCl to wash off any residual glutaraldehyde in human hair, and dry it.3,Production of follicular unit like wigs.①Combination of hair and Polypropylene, All the performation was performed in a sterile bench. At first, an electric furnace was heated at a suitable temperature (170±10℃) and the surface temperature was probed by an industrial thermograph. Polypropylene particles were placed on the stainless steel and heated on the furnace surface until it became melt state. Then the stainless steel was taken out and hair was inserted in the melt polypropylene quickly. Another stainless steel was used to press the melt polypropylene and hair and demounted at room temperature. The obtained intermediate products were lamellar②Elaboration of intermediate products: One side of the polypropylene was cut off with size 11 blade along the longitudinal axis of the hair and the opposite side was cut off partly. Therefore, one barb was elaborated at the base of the stump and the angle of the barb was about 30 degree with a fish-hook shape. The length of the stump was about 4mm, the width was about lmm, and the thickness was 300-400um. One to four hairs were encapsulated in the base.4,Observing the interface between polypropylene and hair conditions and ultra structure of human hair:the wigs was fixed in 2.5% glutaraldehyde 4℃for 24 hours, dehydrated with 30%-100% gradient ethanol, soaked in isamyl acetate for 30min, dried at the critical point. The wigs'surface spray with platinum, the interface between PP and hair surface and ultra structure of human hair was observed by scanning electron microscopy.5,Evaluation wigs'physical strength against the tensile: The hair was pulled to test the wigs'performance of against pull. Results:1,Observing the interface between polypropylene and hair conditions and ultra structure of human hair and: Scanning electron microscopy showed that the contact surface of human hair and polypropylene closely contact, no contact compartment left, the contact surface of polypropylene and hair showed traces of stamping out the hair cuticle, hair bundles of human hair cuticle structure is clear, showing imbricated closely superimposed together.2,evaluation wigs' physical strength against the tensile:Countering the pull tests show pulled off the exposed hair bundles, polypropylene and hair bundle is not easy to separate.Conclusion:The portability graft wig is based on polypropylene materials, it has a good histocompatibility, it is a recognized by clinical long-term retention in the body of the medical materials to ensure the safety of clinical application. The Polypropylene end of follicular unit like wigs is small, barb is apparent, contain various amounts hair, it is similar to the normal hair number of follicle units, it can be more firmly anchored in the subcutaneous tissue. It will get a more natural appearance post-transplant and lay the basis for subsequent animal experiments.PartⅡ: Hstocompatibility and long-term outcomes of follicular unit like wigs after transplantationMethods:1,Experimental animals : 11New Zealand rabbits (from Experimental Animal Center of Southern Medical University) weighing 2,500 to 3,400 g were used.2,Wigs transplantation:wigs were implanted in the head of each rabbit subcutaneously by follicular unit transplantation technique, each rabbit was implanted 40 units wig, with 1～4 wig beam 10units, After the wigs implantation, the 11 rabbits were randomly divided into two groups, A group (N=6) for the observation of long-term effect of transplantation, B group (N=5) observation for the tissue compatibility.3,Observation of histocompatibility:Histocompatibility in transplantation group were observed after 1 week,1 month,3 months,8 months,12 months in sterile conditions, rabbits were randomly selected to take a full thickness skin section head, HE staining for light microscopy and scanning electron microscopy histological observation.4,Observation of long-term outcomes:Observation of long-term outcomes transplantation group's heads were cleaned after 1 week,1 month,3 months,8 months,12 months, and the remaining wig was counted, and calculated the wigs'loss rate. Observing the appearance of wigs and wound healing condition.Results:1,Long-term outcomes of transplantationIt can achieve directional migration through follicular unit transplantation, the direction of wig was good after transplantation, the distribution was nature, the appearance was satisfy. The incision slightly red during the early period, scalp wound healed after a week. No abnormal leakage, rupture and erosion were found one year after transplantation. The loss rate was (2.5±2.7)% at 1 week, (1.25±2.0)% at 1 week-1 month, (0.4±1.0)% at 1-3 months,0% at 3-12-month, the total loss rate was (4.1±4.0)% in 12 months.2,observation of histocompatibility①HE observation of histocompatibility:There were mild inflammatory infiltration by neutrophils and lymphocytes and small vessel congestion at 1 week after implantation. Multi-nucleated giant cells were observed around the polypropylene and hair. Slight epithelial cell proliferation was observed around the hair. Neutrophils, lymphocytes, and multi-nucleated giant cells reduced at 1 month while fibroblasts increased and more epithelial cells surrounded the hair. No significant histological changes were evident at 3 to 8 months following implantation. In comparison with the changes at first week, the infiltration by inflammatory cells was almost disappeared, formation of fibroblasts and collagen fibers surrounded the hair and polypropylene had strengthened, and more epithelial cells were present around the hair. At 12 months, many fibroblasts and collagen fibers were seen around the hair and polypropylene. Inflammatory infiltration by lymphocytes and reject reaction were not identified.②Scanning electron microscope observation of histocompatibility:Scanning electron microscope demonstrated homogeneous, smooth, and translucent polypropylene closely integrated with the surrounding tissue. No tissue dissolution and rejection were found. At 1 week the hair was surrounded by epithelial cells tightly, fibroblast hyperplasia around the polypropylene was not seen apparent. However, fibroblast hyperplasia around the polypropylene and hair was more dynamic at 1 month while epithelial cells around the hair were reduced slightly. At 6 to 12 months, significant fibroblast hyperplasia and collagen fibers were seen. And good histocompatibility maintained with no evidence of tissue necrosis and rejection. Hair degradation was not observed at the end of 12 months. The structure of hair was still clear.Conclusion:After implantation, the appearance of follicular unit wig was nature, the simulation result was good, low loss rate, it can be firmly anchored in the rabbits' skin, while polypropylene and human hair have good tissue biocompatibility in the subcutaneous of New Zealand rabbits, and no adverse reactions were seen. Lay the foundation for subsequent clinical trials. |
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