THE ROLE OF PLATELET-RICH PLASMA IN ANDROGENETIC ALOPECIA: A COMPREHENSIVE NARRATIVE REVIEW

Platelet-rich plasma (PRP) is a promising treatment in regenerative medicine for androgenetic alopecia (AGA). PRP, derived from the patient's blood, contains a concentrated platelet fraction rich in growth factors and bioactive molecules that aid in tissue repair and wound healing. When PRP is administered, these factors are released, stimulating hair growth and regeneration. PRP's mechanism of action involves the release of growth factors like PDGF, TGF-β, VEGF, and IGF, which promote cell proliferation, activate dormant hair follicles, and induce hair cycle growth. PRP also reduces inammation, promotes angiogenesis, and may inhibit 5-alpha reductase activity, which contributes to AGA. By understanding these mechanisms, PRP can be optimized for effective hair restoration therapies in AGA

Updated Molecular Regulation of Hair Growth and Pigmentation by Dermal Papilla Cells / 中国医学科学院学报

There is growing evidence that dermal papilla cells(DPCs)act as the organizing center to induce the cyclic hair regeneration.On one hand,DPCs secrete cytokines or growth factors to regulate the differentiation,proliferation,and migration of epithelial stem cells(EpSCs)and melanocyte stem cells(MeSCs)residing in the bulge region.On the other hand,DPCs manipulate the microenvironment(also termed as niche)for both EpSCs and MeSCs,such as the size of dermal papilla,the distance between dermal papilla and the bulge region,and the lymphatic drainage and sympathetic nerve innervation surrounding the bulge region,thereby orchestrating the cycling hair growth.Recent studies have demonstrated at least four subpopulations existing in dermal papillae,which induce the unilineage transit-amplifying epithelial cells to form the concentric multilayers of hair shafts and sheaths.In addition,emerging study has indicated that sustained psychological stress potentially leads to hyperactivation of the sympathetic nerves that innervate the bulge region.The large amount of norepinephrine released by the nerve endings forces MeSCs to rapidly and abnormally proliferate,resultantly causing the depletion of MeSC pool and the loss of hair pigment.Understanding the molecular regulation of hair growth and pigmentation by DPCs holds substantial promise for the future use of cultured DPCs

Udenafil Induces the Hair Growth Effect of Adipose-Derived Stem Cells

Udenafil, which is a PDE5 inhibitor, is used to treat erectile dysfunction. However, it is unclear whether udenafil induces hair growth via the stimulation of adipose-derived stem cells (ASCs). In this study, we investigated whether udenafil stimulates ASCs and whether increased growth factor secretion from ASCs to facilitate hair growth. We found that subcutaneous injection of udenafil-treated ASCs accelerated telogen-to-anagen transition in vivo. We also observed that udenafil induced proliferation, migration and tube formation of ASCs. It also increased the secretion of growth factors from ASCs, such as interleukin-4 (IL-4) and IL12B, and the phosphorylation of ERK1/2 and NFκB. Furthermore, concomitant upregulation of IL-4 and IL12B mRNA levels was attenuated by ERK inhibitor or NFκB knockdown. Application of IL-4 or IL12B enhanced anagen induction in mice and increased hair follicle length in organ culture. The results indicated that udenafil stimulates ASC motility and increases paracrine growth factor, including cytokine signaling. Udenafil-stimulated secretion of cytokine from ASCs may promote hair growth via the ERK and NFκB pathways. Therefore, udenafil can be used as an ASC-preconditioning agent for hair growth.

Expression Pattern and Role of Klotho in Human Hair Follicles

BACKGROUND: Klotho protein plays a pivotal role in aging regulation. However, it is unclear whether klotho is expressed in human hair follicles and is correlated with hair growth. OBJECTIVE: The purpose of this study was to determine the expression pattern and role of klotho in human hair follicles. METHODS: We examined the klotho expression patterns in human hair follicles from young and aged donors. Furthermore, we examined the functional roles of klotho on human hair growth using klotho siRNA and klotho recombinant protein. RESULTS: Interestingly, klotho was expressed in human hair follicles at both gene and protein levels. In hair follicles, prominent klotho expression was mainly observed in the outermost regions of the outer root sheath and hair bulb matrix cells. Quantification of klotho protein expression in young and aged donors showed that klotho expression decreased with aging. In human hair follicle organ culture, klotho silencing promoted premature catagen induction and inhibited human hair growth. Otherwise, klotho protein prolonged human hair growth. CONCLUSION: These results indicate that klotho might be an important regulatory factor for human hair growth and hair cycle change.

Three Streams for the Mechanism of Hair Graying

Hair graying is an obvious sign of human aging. Although graying has been investigated extensively, the mechanism remains unclear. Here, we reviewed previous studies on the mechanism of graying and seek to offer some new insights. The traditional view is that hair graying is caused by exhaustion of the pigmentary potential of the melanocytes of hair bulbs. Melanocyte dysfunction may be attributable to the effects of toxic reactive oxygen species on melanocyte nuclei and mitochondria. A recent study suggests that bulge melanocyte stem cells (MSCs) are the key cells in play. Graying may be caused by defective MSC self-maintenance, not by any deficiency in bulbar melanocytes. Our previous study suggested that graying may be principally attributable to active hair growth. Active hair growth may produce oxidative or genotoxic stress in hair bulge. These internal stress may cause eventually depletion of MSC in the hair follicles. Taken together, hair graying may be caused by MSC depletion by genotoxic stress in the hair bulge. Hair graying may also be sometimes caused by dysfunction of the melanocytes by oxidative stress in the hair bulb. In addition, hair graying may be attributable to MSC depletion by active hair growth.

Human umbilical cord blood mesenchymal stem cells engineered to overexpress growth factors accelerate outcomes in hair growth

Human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) are used in tissue repair and regeneration; however, the mechanisms involved are not well understood. We investigated the hair growth-promoting effects of hUCB-MSCs treatment to determine whether hUCB-MSCs enhance the promotion of hair growth. Furthermore, we attempted to identify the factors responsible for hair growth. The effects of hUCB-MSCs on hair growth were investigated in vivo, and hUCB-MSCs advanced anagen onset and hair follicle neogeneration. We found that hUCB-MSCs co-culture increased the viability and up-regulated hair induction-related proteins of human dermal papilla cells (hDPCs) in vitro. A growth factor antibody array revealed that secretory factors from hUCB-MSCs are related to hair growth. Insulin-like growth factor binding protein-1 (IGFBP-1) and vascular endothelial growth factor (VEGF) were increased in co-culture medium. Finally, we found that IGFBP-1, through the co-localization of an IGF-1 and IGFBP-1, had positive effects on cell viability; VEGF secretion; expression of alkaline phosphatase (ALP), CD133, and β-catenin; and formation of hDPCs 3D spheroids. Taken together, these data suggest that hUCB-MSCs promote hair growth via a paracrine mechanism.

Effect of Miscanthus sinensis var. purpurascens Flower Extract on Proliferation and Molecular Regulation in Human Dermal Papilla Cells and Stressed C57BL/6 Mice / 中国结合医学杂志

<p><b>OBJECTIVES</b>To investigate the hair growth-promoting effect of Miscanthus sinensis var. purpurascens (MSP) flower extracton on in vitro and in vivo models.</p><p><b>METHODS</b>MSP flower extract was extracted in 99.9% methanol and applied to examine the proliferation of human dermal papilla cells (hDPCs) in vitro at the dose of 3.92-62.50 μg/mL and hair growth of C57BL/6 mice in vivo at the dose of 1000 μg/mL. The expression of transforming growth factor β1 (TGF-β1), hepatocyte growth factor (HGF), β-catenin, substance P was measured by relative quantitative realtime polymerase chain reaction. Histopathological and immunohistochemical analysis were performed.</p><p><b>RESULTS</b>MSP (7.81 μg/mL) down-regulated TGF-β1 and up-regulated HGF and β-catenin in hDPCs (P<0.01). MSP (1000 μg/mL)-treated mice showed the earlier transition of hair follicles from the telogen to the anagen phase. The number of mast cells was lower in the MSP-treated mice than in other groups (P<0.05 vs. NCS group). Substance P and TGF-β1 were expressed in hair follicles and skin of the MSP group lower than that in negative control. Stem cell factor in hair follicles was up-regulated in the MSP-treated mice (P<0.01).</p><p><b>CONCLUSIONS</b>The MSP flower extract may have hair growth-promotion activities.</p>

6-Gingerol inhibits hair cycle via induction of MMP2 and MMP9 expression

ABSTRACT 6-Gingerol is the major active constituent of ginger. In the current study, we aimed to investigate the mechanisms underlying the effects of 6-Gingerol on hair growth. Mice were randomly divided into five groups; after hair depilation (day 0), mice were treated with saline, or different concentrations of 6-Gingerol for 11 days. The histomorphological characteristics of the growing hair follicles were examined after hematoxylin and eosin staining. The results indicated that 6-Gingerol significantly suppressed hair growth compared with that in the control group. And choose the concentration of 6-Gingerol at 1 mg/mL to treated with mice. Moreover, 6-Gingerol (1 mg/mL) significantly reduced hair re-growth ratio, hair follicle number, and hair follicle length, which were associated with increased expression of MMP2 and MMP9. Furthermore, the growth factors, such as EGF, KGF, VEGF, IGF-1 and TGF-β participate in the hair follicle cycle regulation and regulate hair growth. We then measured the concentrations of them using ELISA assays, and the results showed that 6-Gingerol decreased EGF, KGF, VEGF, and IGF-1 concentrations, and increased TGF-β concentration. Thus, this study showed that 6-Gingerol might act as a hair growth suppressive drug via induction of MMP2 and MMP9 expression, which could interfere with the hair cycle.

Knockout of p16INK4a promotes aggregative growth of dermal papilla cells

Summary Objective: Dermal papilla cells (DPCs) are located in the hair follicles and play an important role in hair growth. These cells have the ability to induce hair follicle formation when they display aggregative behavior. DPCs derived from the androgenetic alopecia (AGA) area undergo premature senescence in vitro, associated with p16INK4a expression. The aim of the current study was to investigate the expression of p16INK4a in aggregative and non-aggregative DPCs and the effect of p16INK4a down-regulation in these cells by adenovirus-mediated RNA interference (RNAi). Method: DPCs were isolated and cultured from healthy human scalp. p16INK4a gene and protein were detected in aggregative and non-aggregative cells. Expression of p16INK4a in DPCs was silenced by infection with rAd5-CDKN1A-1p2shRNA. Cell fate was monitored after infection. The growth of cells was measured by MTT assay. Cell cycle was evaluated by flow cytometry (FCM). Results: DPCs were isolated by digestion and showed aggregative behavior for six passages. The expression of p16INK4a showed a clear upward trend in non-aggregative cells when compared with aggregative group. p16INK4a expression was silenced by rAd5-CDKN1A-1p2shRNA (p<0.05). The p16INK4a-silenced cells grew more rapidly and exhibited a trend towards aggregative growth. There was an increase in the proportion of cells in G1 phase, while those in S phase were reduced after p16INK4a gene silencing (p<0.05). Conclusion: Our results suggest that p16INK4a plays an important role in the premature senescence and aggregative behavior of DPCs. These observations can lead to novel therapeutic strategies for treatment of AGA.

Gold thread implantation promotes hair growth in human and mice / 한국실험동물학회지

Thread-embedding therapy has been widely applied for cosmetic purposes such as wrinkle reduction and skin tightening. Particularly, gold thread was reported to support connective tissue regeneration, but, its role in hair biology remains largely unknown due to lack of investigation. When we implanted gold thread and Happy Lift™ in human patient for facial lifting, we unexpectedly found an increase of hair regrowth in spite of no use of hair growth medications. When embedded into the depilated dorsal skin of mice, gold thread or polyglycolic acid (PGA) thread, similarly to 5% minoxidil, significantly increased the number of hair follicles on day 14 after implantation. And, hair re-growth promotion in the gold threadimplanted mice were significantly higher than that in PGA thread group on day 11 after depilation. In particular, the skin tissue of gold thread-implanted mice showed stronger PCNA staining and higher collagen density compared with control mice. These results indicate that gold thread implantation can be an effective way to promote hair re-growth although further confirmatory study is needed for more information on therapeutic mechanisms and long-term safety.

Synergistic Proliferating Effects of Electrical Stimulation and Minoxidil on Human Dermal Papilla Cells / 대한피부과학회지

BACKGROUND: Previous published clinical studies have demonstrated the positive effects of electrical stimulation (ES) on hair growth. Minoxidil (MXD) enhances hair growth by prolonging the anagen phase of hair follicles. MXD is used to promote hair growth in androgenetic alopecia. OBJECTIVE: To investigate the combined effect of ES and MXD on cultured human dermal papilla cells (hDPCs). METHODS: To investigate the combined effect of ES and MXD on cultured human dermal papilla cells (hDPCs). Methods: hDPCs were electrically stimulated with different parameter settings of alternating current. Electrically stimulated hDPCs were incubated in an MXD medium, after which cell proliferation was measured using an MTT assay. Ki-67 and β-catenin expressions were measured by immunofluorescence assay. In addition, Wnt/β-catenin pathway-related gene expressions were measured by real time-PCR, and phosphorylated ERK and AKT protein levels were measured by western blot assay. RESULTS: The combination of 8 V-1 MHz ES and MXD treatment promoted hDPC proliferation effectively, compared with that in the control, ES alone, or MXD alone treatment groups. The immunofluorescence assay showed that the expression of Ki-67 and β-catenin significantly increased in the combined treatment group. Most of the Wnt/β-catenin pathway-related gene expressions increased more with combined treatment than with the control, ES alone, or MXD alone treatments. However, there were no significant differences in the expression levels of phosphorylated ERK and AKT among the treatment groups. CONCLUSION: ES combined with MXD treatment had a synergistic effect on the proliferation of hDPCs. This might be through the synergistic activation of the Wnt/β-catenin pathway.

Hair growth promoting effects of emodin in telogenic C57BL/6 mice

Emodin is an anthraquinone derivative from the roots of Rheum officinale Baill that possesses a variety of biological activities, including inhibition of 5α-reductase and prostaglandin D2. In this study, we investigated whether emodin promotes hair growth. After emodin was topically applied to the shaved dorsal skin of telogenic C57BL/6 N mice, the hair growth rate and morphological analysis were evaluated in dorsal skin for 15 days. After 13 days of treatment, minoxidil or emodin (0.01% or 0.1%)-treated groups showed remarkable regrowth of hairs relative to the vehicle control group. Scoring of the hair growth and rate of hair growth area for 15 days revealed that groups treated with minoxidil and 0.1% emodin were significantly higher than the vehicle control group. Histological examination revealed the emodin and minoxidil groups markedly recovered the number and morphology of hair follicles, including the subcutis depth, relative to the vehicle group. These results suggest that emodin has an excellent promoting effect in hair growth similar to that of minoxidil and might be useful for treatment of baldness or alopecia.

Determination of 17 Characteristic Ingredients of Plant Extracts in Hair Growth Cosmetics by Ultra High Performance Liquid Chromatography / 分析化学

A method was developed for the simultaneous determination of 17 characteristic ingredients of plant extracts, including paeoniflorin, hydroxysafflor yellow A, calycosin_7_glucoside ferulic acid, etc. , in hair growth cosmetics using ultra high performance liquid chromatography ( UPLC ) . Different cosmetic samples were extracted by ultrasonic_assisted extraction with the solvent of methanol/water (4∶1, V/V) solution. After demulsified by the addition of appropriate amount of NaCl and high speed centrifugation, the supernatant was transferred and analyzed with UPLC. The separation was conducted on a Waters reversed phase column of ACQUITY UPLC CSH C18(50 mm×2. 1 mm, 1. 7μm), and the mobile phases were methanol and the solution of 0. 05% phosphate in water. The detection was performed with a photodiode_array ( PDA) detector. The linear range was 0 . 2-25 mg/L with correlation coefficients higher than 0 . 999 . The limits of detection were within 0. 3-1. 5 mg/kg, and the limits of quantification were from 1. 0 to 4. 0 mg/kg. The average recoveries of 17 characteristic ingredients were within 93 . 5%-105 . 0%, with the intra_and inter_day precision ( n=6 ) less than 4. 6%. This method was simple, rapid, with good_repeatability, and had been applied to the analysis of real samples.

Hair Growth Promoting Potential of Phospholipids Purified from Porcine Lung Tissues

BP201, porcine lung tissue-derived phospholipids, consists of phosphatidylcholine as a major phospholipid species. BP201 promoted hair growth after application onto the shaved backs of BALB/c and C3H mice. Its effect was enhanced when applied together with minoxidil (MNX) in C3H mice. When the tissue specimens prepared from the shaved skins of BP201-treated and control mice were microscopically examined, the total numbers of hair follicles in both anagen and telogen phases of BP201-treated mice were significantly higher than those of control mice. The numbers of hair follicles in the anagen phase of BP201-treated mice were also higher than those of control mice. In combination with MNX, BP201 further increased the total number of hair follicles, but did not alter the percentage of hair follicles in the anagenic phase. BP201 also increased the proliferation of human hair follicle dermal papilla cells. Collectively, BP201 possesses hair growth promoting potential, which would suggest its use singly or in combination for hair growth products.

Effectiveness of the combinational treatment of Laminaria japonica and Cistanche tubulosa extracts in hair growth / 한국실험동물학회지

Since scalp hair loss has increased recently even in young people, seriously affecting individual's quality of life, the hair growth-stimulating effects of Laminaria japonica extract (LJE) and Cistanche tubulosa extract (CTE) were investigated. After confirming anagen phase of follicles under shaving, male C57BL/6 mice were dermally applied with 3% Minoxidil or orally administered with the combinations of LJE and CTE for 21 days. Minoxidil promoted the hair regrowth and increased gamma-glutamyl transpeptidase (gamma-GTP) and alkaline phosphatase (ALP) activities. In addition, Minoxidil up-regulated epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) levels. Co-administration of LJE and CTE at 54 mg/kg LJE plus 162 mg/kg CTE exerted synergistic promoting effects on the hair regrowth, comparable to 3% Minoxidil. LJE preferentially enhanced ALP activity, while CTE increased both gamma-GTP and ALP activities as well as EGF and VEGF expressions. In vivo air pouch inflammation model, carrageenan-induced vascular exudation and increased nitric oxide and prostaglandin E2 concentrations in the exudates were synergistically suppressed by co-administration of LJE and CTE. In addition, inflammatory cell infiltration was substantially inhibited by the combinational treatment. The results suggest that combinational oral treatment with LJE and CTE in appropriate doses and ratios prevent hair loss and improve alopecia, which might be in part mediated by their anti-inflammatory activities.

Hirsutism: diagnosis and treatment / Hirsutismo: diagnóstico e tratamento

Hirsutism is defined as excessive terminal hair growth in androgen-dependent areas of the body in women, which grows in a typical male distribution pattern. Hirsutism is a common clinical problem in women, and the treatment depends on the cause. The condition is often associated with a loss of self-esteem. Hirsutism reflects the interaction between circulating androgen concentrations, local androgen concentrations, and the sensitivity of the hair follicle to androgens. Polycystic ovary syndrome and idiopathic hirsutism are the most common causes of the condition. A woman’s history and, physical examination are particularly important in evaluating excess hair growth. The vast majority of women with hirsutism have the idiopathic variety, and the diagnosis is made by exclusion. Serum testosterone level > 200 ng/dL is highly suggestive of adrenal or ovarian tumor. Treatment of hirsutism should be based on the degree of excess hair growth presented by the patient and in the pathophysiology of the disorder. Treatment includes lifestyle therapies, androgen suppression, peripheral androgen blockage, and cosmetic treatments. The current review discusses definition, pathogenesis, physiopathology, differential diagnosis, diagnostic strategies, and treatment.

O hirsutismo é definido como o excesso de crescimento terminal de pelos em áreas dependentes de andrógenos no corpo de mulheres, com crescimento em um padrão de distribuição tipicamente masculino. O hirsutismo é um problema clínico comum em mulheres, e o tratamento depende da causa. A condição está geralmente associada com a perda de autoestima. O hirsutismo reflete a interação entre as concentrações de andrógenos circulantes, concentrações locais de andrógenos e a sensibilidade do folículo capilar aos androgênios. A síndrome dos ovários policísticos e o hirsutismo idiopático são as causas mais comuns do transtorno. O histórico e o exame físico são particularmente importantes na avaliação do excesso de crescimento de pelos. A maioria das mulheres com hirsutismo possui a variedade idiopática, e o diagnóstico é feito por exclusão. Uma concentração sérica de testosterona > 200 ng/dL é altamente sugestiva de tumor ovariano ou de adrenal. O tratamento do hirsutismo deve ser baseado no nível de excesso de crescimento dos pelos e a fisiopatologia do transtorno. O tratamento inclui alterações no estilo de vida, supressão de andrógenos, bloqueio periférico de andrógenos e tratamentos cosméticos. A presente revisão discute definição, patogênese, fisiopatologia, diagnóstico diferencial e estratégias de diagnóstico e tratamento.

Promotional effects of Sargassum fusiforme fractions on hair growth via in vitro and in vivo models / 동물의과학연구지

Sargassum fusiforme has traditionally been widely consumed in Asia as a food, and it has gained much attention due to its high nutritional, pharmaceutical, and industrial value. This study aimed to examine the promotional effects of ethanol extract (ET) and fraction obtained from ethyl acetate (FR) of S. fusiforme on hair growth in C57BL/6 mice and HaCaT cells. Five-week-old mice were used to compare hair regrowth during application of ET and FR for 21 days. Hair regrowth was evaluated by macroscopic observation and verified by hematoxylin-eosin tissue staining. Levels of mRNA expression of factors relevant to the hair growth cycle such as keratinocyte growth factor (KGF), vascular endothelial growth factor (VEGF), and transforming growth factor-beta1 (TGF-beta1) were examined by quantitative polymerase chain reaction (qPCR). Our results showed that ET and FR successfully promoted hair regrowth in shaved C57BL/6 mice at a dose >20 mg/kg. Moreover, ET and FR were effective in stimulating expression of KGF and VEGF mRNAs in a dose-dependent manner, whereas TGF-beta1 was not activated. These results indicate that ET and FR of S. fusiforme effectively promoted hair growth and gene expression relevant to hair growth cycles in both in vitro and in vivo models.

Effect of Phellius linteus water extract on benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is one of the most common diseases among elderly men. As the old-age population is increasing recently, it is to our interest to observe the growing BPH within them. In BPH, the dihydrotestosterone (DHT) acts as promotes prostate growth. It inhibits enzyme 5alpha-reductase that is involved in the conversion of testosterone to the DHT activity which reduces the excessive prostate growth. Through experiments, the effects of Phellius linteus water extract performed on the BPH rats were induced by testosterone treatments. For 12 weeks, Sprague-Dawley rats were treated with testosterone for the induction of BPH. Rats were divided into four experimental groups: the not treated group (N), the testosterone injection and D.W treatment group (TN), the testosterone injection and Phellinus linteus treatment group (TP) and testosterone injection and finasteride treatment group (TF). Prostate weight, volume and weight ratio in the TP group and the TF group were significantly lower than the TN group. Testosterone and DHT levels in the TN group were significantly higher than that of the N group. And the TP group was significantly decreased than that of the TN group. While prostates of control rats revealed severe acinar gland atrophy and stromal proliferation; the TP and TF groups showed trophic symptoms and were lined by flattened epithelial cells, thus, the stromal proliferation is relatively low as compared to the TN group. These suggest that Phellinus linteus water extracts may be an useful remedy for treating the benign prostatic hyperplasia.

Action Mechanism of Chamaecyparis obtusa Oil on Hair Growth

This study was carried out to examine the action mechanism of Chamaecyparis obtusa oil (CO) on hair growth in C57BL/6 mice. For alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (gamma-GT) activities in the skin tissue, at week 4, the 3% minoxidil (MXD) and 3% CO treatment groups showed an ALP activity that was significantly higher by 85% (p < 0.001) and 48% (p < 0.05) and an gamma-GT activity that was significantly higher by 294% (p < 0.01) and 254% (p < 0.05) respectively, as compared to the saline (SA) treatment group. For insulin-like growth factor-1 (IGF-1) mRNA expression in the skin tissue, at week 4, the MXD and CO groups showed a significantly higher expression by 204% (p < 0.05) and 426% (p < 0.01) respectively, as compared to the SA group. At week 4, vascular endothelial growth factor (VEGF) expression in the MXD and CO groups showed a significantly higher expression by 74% and 96% (p < 0.05) respectively, however, epidermal growth factor (EGF) expression in the MXD and CO groups showed a significantly lower expression by 66% and 61% (p < 0.05) respectively, as compared to the SA group. Stem cell factor (SCF) expression in the MXD and CO groups was observed by immunohistochemistry as significant in a part of the bulge around the hair follicle and in a part of the basal layer of the epidermis. Taking all the results together, on the basis of effects on ALP and gamma-GT activity, and the expression of IGF-1, VEGF and SCF, which are related to the promotion of hair growth, it can be concluded that CO induced a proliferation and division of hair follicle cells and maintained the anagen phase. Because EGF expression was decreased significantly, CO could delay the transition to the catagen phase.

Effect of IGF-I on Hair Growth Is Related to the Anti-Apoptotic Effect of IGF-I and Up-Regulation of PDGF-A and PDGF-B

BACKGROUND: Insulin-like growth factor-I (IGF-I) shares a high degree of structural and functional homology with insulin and is a potent mitogen supporting cell growth and survival in many kinds of the tissues and cells. It also plays a role in some differentiation and anti-apoptotic functions. In previous reports, it has been shown that IGF-I stimulates hair follicle (HF) growth, maintains the anagen stage, and postpones the catagen stage. OBJECTIVE: The exact mechanism of the effect of IGF-I on HF growth is not yet established. Therefore, we investigated the relationships between IGF-I and various other factors (i.e. apoptosis related molecules, pro-inflammatory cytokines, other growth factors, etc.) in the control of HF growth. METHODS: The effect of IGF-I on human hair growth was measured using an organ culture model of human HFs and compared with a control group that did not receive IGF-I. We also measured mRNA expression of factors related to hair growth and apoptosis (which was determined by reverse transcription polymerase chain reaction (RT-PCR). RT-PCR was done on days 2, 4, 6, and 8 of organ culture. RESULTS: In organ cultured human hair follicles, IGF-I had a positive effect on the rate of linear hair growth. IGF-I maintained the anagen phase. IGF-I increased the expression of platelet-derived growth factor (PDGF)-A, PDGF-B and the expression ratio of Bcl-2/Bax. CONCLUSION: The effect of IGF-I on hair growth appears to be related to the upregulation of PDGF-A and PDGF-B and to the anti-apoptotic effect of IGF-I.