Synergistic effect of PDGF and FGF2 for cell proliferation and hair inductive activity in murine vibrissal dermal papilla in vitro

LncRNA RP11-818O24.3 promotes hair-follicle recovery via FGF2-PI3K/Akt signal pathway

A previous study indicated that patients with androgenic alopecia (AGA) have significantly reduced levels of LncRNA RP11-818O24.3. This study investigates whether LncRNA RP11-818O24.3 promotes hair-follicle recovery and its possible mechanism. Hair alteration and cutaneous histopathological changes induced by testosterone propionate were observed by H&E and bromodeoxyuridinc (BrdU) stain to evaluate the therapeutic effect of LncRNA RP11-818O24.3 in C57BL/6 J mice. The cellular viability was analyzed in LncRNA RP11-818O24.3-transfected human hair-follicle stem cells (HFSCs) in vitro. The signaling pathways and pro-proliferative factors were investigated by transcriptomic gene sequencing and qRT-PCR. LncRNA RP11-818O24.3 transfection successfully recovered hair growth and hair-follicle cells in AGA mice. In a series of HFSC studies in vitro, LncRNA RP11-818O24.3 transfection greatly promoted cellular proliferation and decreased cellular apoptosis. Transcriptome gene sequencing suggested that the phosphatidylinositol 3-kinase (PI3K)-Akt pathway was upregulated by LncRNA RP11-818O24.3. The qRT-PCR results showed that fibroblast growth factor (FGF)-2 was 14-times upregulated after LncRNA RP11-818O24.3 transfection. Hair-follicle recovery activity of LncRNA RP11-818O24.3 may involve the upregulation of FGF2 and PI3K-Akt to promote follicle stem cell survival. These data not only provide a theoretical basis for AGA development but also reveal a novel therapeutic method for AGA patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-024-00624-3.

Platelet-rich fibrin (PRF) modified nano-hydroxyapatite/chitosan/gelatin/alginate scaffolds increase adhesion and viability of human dental pulp stem cells (DPSC) and osteoblasts derived from DPSC

Bone tissue regeneration strategies have incorporated the use of natural polymers, such as hydroxyapatite (nHA), chitosan (CH), gelatin (GEL), or alginate (ALG). Additionally, platelet concentrates, such as platelet-rich fibrin (PRF) have been suggested to improve scaffold biocompatibility. This study aimed to develop scaffolds composed of nHA, GEL, and CH, with or without ALG and lyophilized PRF, to evaluate the scaffold's properties, growth factor release, and dental pulp stem cells (DPSC), and osteoblast (OB) derived from DPSC viability. Four scaffold variations were synthesized and lyophilized. Then, degradation, swelling profiles, and morphological analysis were performed. Furthermore, PDGF-BB and FGF-B growth factors release were quantified by ELISA, and cytotoxicity and cell viability were evaluated. The swelling and degradation profiles were similar in all scaffolds, with pore sizes ranging between 100 and 250 μm. FGF-B and PDGF-BB release was evidenced after 24 h of scaffold immersion in cell culture medium. DPSC and OB-DPSC viability was notably increased in PRF-supplemented scaffolds. The nHA-CH-GEL-PRF scaffold demonstrated optimal physical-biological characteristics for stimulating DPSC and OB-DPSC cell viability. These results suggest lyophilized PRF improves scaffold biocompatibility for bone tissue regeneration purposes.

Phloroglucinol Enhances Anagen Signaling and Alleviates H2O2-Induced Oxidative Stress in Human Dermal Papilla Cells

Phloroglucinol (PG) is one of the abundant isomeric benzenetriols in brown algae. Due to its polyphenolic structure, PG exhibits various biological activities. However, the impact of PG on anagen signaling and oxidative stress in human dermal papilla cells (HDPCs) is unknown. In this study, we investigated the therapeutic potential of PG for improving hair loss. A non-cytotoxic concentration of PG increased anagen-inductive genes and transcriptional activities of β-Catenin. Since several anagen-inductive genes are regulated by β-Catenin, further experiments were performed to elucidate the molecular mechanism by which PG upregulates anagen signaling. Various biochemical analyses revealed that PG upregulated β-Catenin signaling without affecting the expression of Wnt. In particular, PG elevated the phosphorylation of protein kinase B (AKT), leading to an increase in the inhibitory phosphorylation of glycogen synthase kinase 3 beta (GSK3β) at serine 9. Treatment with the selective phosphoinositide 3-kinase/AKT inhibitor, LY294002, restored the increased AKT/GSK3β/β-Catenin signaling and anagen-inductive proteins induced by PG. Moreover, conditioned medium from PG-treated HDPCs promoted the proliferation and migration of human epidermal keratinocytes via the AKT signaling pathway. Subsequently, we assessed the antioxidant activities of PG. PG ameliorated the elevated oxidative stress markers and improved the decreased anagen signaling in hydrogen peroxide (H2O2)-induced HDPCs. The senescence-associated β-galactosidase staining assay also demonstrated that the antioxidant abilities of PG effectively mitigated H2O2-induced senescence. Overall, these results indicate that PG potentially enhances anagen signaling and improves oxidative stress-induced cellular damage in HDPCs. Therefore, PG can be employed as a novel therapeutic component to ameliorate hair loss symptoms.

Dermal papilla cells cultured as spheres improve angiogenesis

Tissue-engineered skin represents a helpful strategy for the treatment of deep skin injuries. Nevertheless, these skin substitutes must promote and encourage proper vascularization for a successful graft take. Previous work showed that dermal papilla cells (DPC) favour an earlier neovascularization process of grafted skin substitute contributing to the rapid maturation of the neovascular network, reducing inflammation and favouring extracellular matrix remodelling in nude mice. Based on these results, we studied the influence of DPC and its culture conditions on the different stages of angiogenesis in in vitro models. Here, we showed that DPC cultured as spheres favour the expression of angiogenic factors such as VEGF, FGF2 and angiogenin compared to their monolayer culture. To study the effects of DPC on the different stages of angiogenesis, an in vitro model has been adapted. DPC cultured as spheres significantly enhanced HUVEC migration and tubule formation, indicating the importance of employing physiological culture systems that provide a closer representation of cell behaviour and interactions occurring in vivo. Overall, these results allow us to speculate that the use of DPC spheres in skin substitutes could promote its grafting, vascularization and vascular network maturation through the secretion of angiogenic factors. This approach has great potential to improve clinical outcomes in regenerative medicine and skin wound repair.

Establishment and characterization of matched immortalized human frontal and occipital scalp dermal papilla cell lines from androgenetic alopecia

Androgenetic alopecia (AGA), also known as male pattern baldness, is a common hair loss condition influenced by genetic and hormonal factors. Variations in gene expression and androgen responsiveness have been observed between the frontal and occipital regions of AGA patients. However, obtaining and cultivating frontal hair follicles is challenging. Therefore, no matched frontal and occipital dermal papilla (DP) cell lines have been reported yet. This study aimed to establish matched immortalized human frontal and occipital scalp DP cell lines from AGA patients. Simian virus 40 large T antigen (SV40T-Ag) and human telomerase reverse transcriptase (hTERT) were introduced into primary human DP cells. The obtained cell lines were characterized by assessing their gene expression patterns, androgen receptor (AR) levels, and the presence of 5-alpha reductase (5αR). Additionally, we examined their response to dihydrotestosterone (DHT) and evaluated cell viability. The conditioned medium from the frontal DP cell line inhibited human hair follicle growth, leading to reduced keratinocyte proliferation and increased apoptosis. Furthermore, when the cells were cultured in a 3D environment mimicking in vivo conditions, the 3D cultured frontal DP cell line exhibited weaker sphere aggregation than the occipital DP cell line due to the increased expression of matrix metalloproteinase 1 (MMP1), MMP3, and MMP9. Additionally, the expression of DP signature genes was inhibited in the 3D cultured frontal DP cell line. These matched frontal and occipital DP cell lines hold significant potential as valuable resources for research on hair loss. Their establishment allows us to investigate the differences between frontal and occipital DP cells, contributing to a better understanding of the molecular mechanisms underlying AGA. Furthermore, these cell lines may be valuable for developing targeted therapeutic approaches for hair loss conditions.

Nanotechnology-based techniques for hair follicle regeneration

The hair follicle (HF) is a multicellular complex structure of the skin that contains a reservoir of multipotent stem cells. Traditional hair repair methods such as drug therapies, hair transplantation, and stem cell therapy have limitations. Advances in nanotechnology offer new approaches for HF regeneration, including controlled drug release and HF-specific targeting. Until recently, embryogenesis was thought to be the only mechanism for forming hair follicles. However, in recent years, the phenomenon of wound-induced hair neogenesis (WIHN) or de novo HF regeneration has gained attention as it can occur under certain conditions in wound beds. This review covers HF-specific targeting strategies, with particular emphasis on currently used nanotechnology-based strategies for both hair loss-related diseases and HF regeneration. HF regeneration is discussed in several modalities: modulation of the hair cycle, stimulation of progenitor cells and signaling pathways, tissue engineering, WIHN, and gene therapy. The HF has been identified as an ideal target for nanotechnology-based strategies for hair regeneration. However, some regulatory challenges may delay the development of HF regeneration nanotechnology based-strategies, which will be lastly discussed.

Effect of platelet counts and activator in platelet-rich plasma on the treatment of androgenetic alopecia, split-head comparison: A randomised, double-blind study

Background Androgenetic alopecia is a common, chronic, non-scarring alopecia. It is characterised by stepwise miniaturisation of the hair follicles, due to alteration in the hair cycle dynamics, leading to the transformation of terminal hair follicles into a vellus ones. Oral finasteride and topical minoxidil are the only approved drugs for treating this condition. Due to a limited number of effective therapies for androgenetic alopecia, platelet-rich plasma may be an effective alternative treatment. Aims To study the effect of activator in platelet-rich plasma and baseline platelet count in platelet-rich plasma on the treatment of androgenetic alopecia. Methods A randomised, double-blind split-head comparative study. The sample size was calculated and randomisation was done. Patients with androgenetic alopecia were allocated into two groups; in the first group, autologous activated platelet-rich plasma was injected in the right half of the affected scalp and autologous non-activated platelet-rich plasma was injected in the left half of the affected scalp and vice versa in the second group. Patients were also categorised on the basis of platelet counts in their platelet-rich plasma in three groups; group A (6-8 lakh/mm3), group B (8.1-10 lakh/mm3) and group C (>10 lakh/mm3). Interventions were done monthly for three months and followed up for the next three months. Effects of interventions were assessed by hair density, hair thickness, patient self-assessment and clinical photography. Results A total of 80 patients were included in the study. Activated platelet-rich plasma produced significant improvement of hair density after four months and hair thickness at 6 months. An increase in platelet count led to a significant increase in hair density and hair thickness after three and four months respectively and a highly significant increase in both parameters at the end of the study. Limitations Long-term follow-up of cases was not done and no measurement of vellus hair count was done. Conclusion There is a significant effect of activator and platelet count of the platelet-rich plasma on hair density as well as hair thickness.

Cell Therapy for Androgenetic Alopecia: Elixir or Trick?

Androgenetic alopecia is the most common cause of hair loss aggravated by increased life pressure, tension, and anxiety. Although androgenetic alopecia (AGA) does not significantly effect physical health, it can have serious negative impact on the mental health and quality of life of the patient. Currently, the effect of medical treatment for AGA is not idealistic, stem cell-based regenerative medicine has shown potential for hair regrowth and follicle repair, but the long-term effect and mechanism of stem cell therapy is not quite explicit. In this review, we summarize the methods, efficacy, mechanism, and clinical progress of stem cell therapies for AGA by now, hope it will present a more comprehensive view in this topic.

Effects of Allium hookeri Extracts on Hair-Inductive and Anti-Oxidative Properties in Human Dermal Papilla Cells

Oxidative stress and cellular senescence in dermal papilla cells (DPCs) are major etiological factors causing hair loss. In this study, the effect of the Allium hookeri extract (AHE) on hair-inductive and anti-oxidative properties was investigated in human DPCs. As a result, it was found that a non-cytotoxic concentration of the extracts increased the viability and size of the human DPC spheroid, which was associated with the increased expression of hair-growth-related genes in cells. To determine whether or not these effects could be attributed to intracellular anti-oxidative effects, liquid chromatography-mass spectrometry alongside various biochemical analyses are conducted herein. An ingredient called alliin was identified as one of the main components. Furthermore, AHE treatment induced a significant decrease in H₂O₂-mediated cytotoxicities, cell death, and cellular senescence in human DPCs. Upon analyzing these results with a molecular mechanism approach, it was shown that AHE treatment increased β-Catenin and NRF2 translocation into the nucleus while inhibiting the translocation of NF-κB (p50) through p38 and PKA-mediated phosphorylations of GSK3β, an upstream regulator of those proteins. These results overall indicate the possibility that AHE can regulate GSK3β-mediated β-Catenin, NRF2, and NF-κB signaling to enhance hair-inductive properties and ultimately protect against oxidative stress-induced cellular damage in human DPCs.

Innovative Approaches and Advances for Hair Follicle Regeneration

Pathological hair loss (also known as alopecia) and shortage of hair follicle (HF) donors have posed an urgent requirement for HF regeneration. With the revelation of mechanisms in tissue engineering, the proliferation of HFs in vitro has achieved more promising trust for the treatments of alopecia and other skin impairments. Theoretically, HF organoids have great potential to develop into native HFs and attachments such as sweat glands after transplantation. However, since the rich extracellular matrix (ECM) deficiency, the induction characteristics of skin-derived cells gradually fade away along with their trichogenic capacity after continuous cell passaging in vitro. Therefore, ECM-mimicking support is an essential prelude before HF transplantation is implemented. This review summarizes the status of providing various epidermal and dermal cells with a three-dimensional (3D) scaffold to support the cell homeostasis and better mimic in vivo environments for the sake of HF regeneration. HF-relevant cells including dermal papilla cells (DPCs), hair follicle stem cells (HFSCs), and mesenchymal stem cells (MSCs) are able to be induced to form HF organoids in the vitro culture system. The niche microenvironment simulated by different forms of biomaterial scaffold can offer the cells a network of ordered growth environment to alleviate inductivity loss and promote the expression of functional proteins. The scaffolds often play the role of ECM substrates and bring about epithelial-mesenchymal interaction (EMI) through coculture to ensure the functional preservation of HF cells during in vitro passage. Functional HF organoids can be formed either before or after transplantation into the dermis layer. Here, we review and emphasize the importance of 3D culture in HF regeneration in vitro. Finally, the latest progress in treatment trials and critical analysis of the properties and benefits of different emerging biomaterials for HF regeneration along with the main challenges and prospects of HF regenerative approaches are discussed.

Hair Follicle Development and Cashmere Traits in Albas Goat Kids

The objectives of this trial were to study the growth and development of hair follicles and cashmere traits in cashmere goats and to provide a theoretical basis for the regulation of secondary hair follicle development and the scientific breeding selection of cashmere goats. Twelve single-fetal female kids were selected as research objects. A long-term tracking plan was created to regularly determine their growth performance, cashmere performance, and hair follicle traits. The results showed no significant difference in live weight after the first and second combing. The cashmere yield and unit yield of the first combing were significantly higher than those of the second combing (p < 0.05). Sections of hair follicles showed that the primary hair follicles are almost fully developed by 1 month, and the secondary hair follicles are fully developed by 5-6 months after birth. The primary hair follicle density (PFD) and secondary hair follicle density (SFD) were highest at birth and decreased within 1 month; and SFD was stable at 5-6 months of age. The change of MSFD took a maximum time of 2 to 3 months. The S:P increase reached its peak at 6 months. BMP4 expression increased with time. FGF2, FGF21 and BMP7 were higher at 3 months old than at the other two-time points. In conclusion, this study determined the total development time of primary and secondary hair follicles from morphology and speculated that FGF2, FGF21, and BMP7 may play a regulatory role in developing secondary hair follicles. Therefore, the period from birth to 6 months of age was the best time to regulate secondary hair follicle development in cashmere goats kids. The traits of the hair follicle and cashmere at 6 months of age could be breeding selection indicators for cashmere goats.

Hair Growth Regulation by Fibroblast Growth Factor 12 (FGF12)

The fibroblast growth factor (FGF) family has various biological functions, including cell growth, tissue regeneration, embryonic development, metabolism, and angiogenesis. In the case of hair growth, several members of the FGF family, such as FGF1 and FGF2, are involved in hair growth, while FGF5 has the opposite effect. In this study, the regulation of the hair growth cycle by FGF12 was investigated. To observe its effect, the expression of FGF12 was downregulated in mice and outer root sheath (ORS) by siRNA transfection, while FGF12 overexpression was carried out using FGF12 adenovirus. For the results, FGF12 was primarily expressed in ORS cells with a high expression during the anagen phase of hair follicles. Knockdown of FGF12 delayed telogen-to-anagen transition in mice and decreased the hair length in vibrissae hair follicles. It also inhibited the proliferation and migration of ORS cells. On the contrary, FGF12 overexpression increased the migration of ORS cells. FGF12-overexpressed ORS cells induced the telogen-to-anagen transition in the animal model. In addition, FGF12 overexpression regulated the expression of PDGF-CC, MDK, and HB-EGF, and treatment of these factors exhibited hair growth promotion. Altogether, FGF12 promoted hair growth by inducing the anagen phase of hair follicles, suggesting the potential for hair loss therapy.

Heat-Killed Enterococcus faecalis EF-2001 Induces Human Dermal Papilla Cell Proliferation and Hair Regrowth in C57BL/6 Mice

Minoxidil is the most widely used treatment for hair growth, but has been associated with several side effects. In this study, we investigated the effects of heat-killed Enterococcus faecalis EF-2001 on hair loss prevention and regrowth using human dermal papilla cells and male C57BL/6 mice. To examine the effects of EF-2001, we used minoxidil as the positive control. In the in vitro experiments, EF-2001 treatment (75-500 μg/mL) led to the proliferation of human dermal papilla cells in a concentration-dependent manner. In the in vivo experiment, the topical application of 200 µL EF-2001 on the dorsal surface of C57BL/6 male mice led to hair growth. Changes in hair regrowth were examined by visual comparison and hematoxylin and eosin staining of skin sections. We also determined the expression levels of marker genes (Wnt) and growth factors (fibroblast growth factor, insulin growth factor 1, and vascular endothelial growth factor) in the skin tissues of the back of each mouse using a quantitative polymerase chain reaction. EF-2001 accelerated the progression of hair regrowth in mice and promoted hair-follicle conversion from telogen to anagen, likely by increasing the expression levels of growth factors and marker genes.

Extremely Low-Frequency Electromagnetic Fields Increase Cytokines in Human Hair Follicles through Wnt/β-Catenin Signaling

Hair loss is a chronic disorder that affects many people; however, a complete treatment has not yet been developed. Therefore, new therapeutic agents for preventing hair loss must be developed, and electromagnetic field (EMF) therapy has been proven to be a promising medical treatment in various fields, including hair loss treatment. This study evaluated the effect of extremely low-frequency electromagnetic field (ELF-EMF) intensity and exposure time by analyzing the expression of cytokines and anagen-related molecules, which influence hair activation and growth, in hair bulb spheroid (HBS) and hair follicle (HF) organ cultures. ELF-EMFs did not induce toxicity in the HBSs, as verified via the lactate dehydrogenase (LDH) assay. Moreover, an ELF-EMF intensity of 5–20 G promoted the expression of ALP, versican, β-catenin, and several cytokines (VEGF, PDGF, FGF-10, and ET-1) in HBSs. Immunohistochemical staining showed that ELF-EMF at an intensity of 5–20 G upregulated ALP and β-catenin and decreased TUNEL staining in HBS. Moreover, HFs exposed to ELF-EMF for 60 min exhibited an increase in hair length and a 1.5-fold increase in IL-4, ICAM-1, ALP, and versican mRNA expression compared to the control. Immunohistochemical staining indicated that 60 min of ELF-EMF can increase the expression of ALP and β-catenin and decreases TUNEL staining in organ cultures. Collectively, our results demonstrated that ELF-EMF exposure at a 10 G intensity for 60 min promoted hair shaft growth in HFs due to the effect of cytokines and adhesion molecules via the Wnt/β-catenin pathway. Therefore, ELF-EMF is a promising treatment for hair loss.

MicroRNA-149-mediated MAPK1/ERK2 Suppression Attenuates Hair Follicle stem Cell Differentiation

Hair follicle stem cells (HFSCs) are responsible for hair growth and hair follicle (HF) regeneration. microRNAs (miRNAs) have been demonstrated to be involved in the differentiation of HFSCs. Thus, present study aimed to explore the potential role of miR-149 in the differentiation of HFSCs. The isolated HFSCs were identified by flow cytometric sorting. miR-149 expression was determined during differentiation of HFSCs. Gain- and loss-of-function approaches were conducted to explore the roles of miR-149, MAPK1/ERK2, and FGF2/c-MYC in colony formation and proliferation of HFSCs. Furthermore, in vivo assays were undertaken in miR-149 knockout mice to confirm their roles in HFSC differentiation. miR-149 was found to be down-regulated during HFSC differentiation, and overexpressed miR-149 restricted the proliferation and differentiation of HFSCs. miR-149 was confirmed to target and inhibit MAPK1/ERK2, which was highly expressed in and positively associated with HFSC differentiation. The MAPK1/ERK2 promotion in HFSC differentiation was achieved by augmenting expression of FGF2 and c-MYC. The in vitro effects of miR-149 were validated in in vivo experiments. Taken together, up-regulated miR-149 restricted HFSC differentiation and hair growth by targeting MAPK1/ERK2 to reduce expression of FGF2 and c-MYC, which sheds light on the underlying molecular mechanism on hair growth.

Clinical observation of basic fibroblast growth factor (bFGF) combined with minoxidil in the treatment of male androgenetic alopecia

BACKGROUND

Androgenetic alopecia (AGA) has been one of the most common progressive hair loss in the world, which affects 80% of white males. To date, only minoxidil and finasteride have been approved by FDA for the treatment of AGA. However, limited therapeutic effect and the toxic adverse events of these drugs limit their applications. Therefore, it is still an urgent clinical problem to find effective therapeutic drugs and medication regimen.

OBJECTIVE

The goal was to explore the efficacy and side effects of basic fibroblast growth factor (bFGF) combined with minoxidil in the treatment of male patients with early stage of androgenetic alopecia (AGA).

METHODS

Using a randomized control method, 80 male patients with androgenetic alopecia in Hamilton grade II-IV were randomly divided into two groups, with 40 patients in each group. The Group A: 1 ml minoxidil for external use twice a day; Group B: 3500 IU basic fibroblast growth factor (bFGF) and 1 ml minoxidil for external use twice a day. The selected patients received global photograph evaluation before treatment, 3 months after treatment, and 6 months after treatment, and the curative effect was judged according to the changes in the area and degree of hair loss on the top of the head and anterior parietal area of the patients shown in the photographs before and after treatment. At the same time, each patient had a satisfaction questionnaire survey before treatment, 3 months after treatment, and 6 months after treatment. During the research period, the adverse reactions of the patients were recorded.

RESULTS

After 3 months and 6 months of treatment, the effective rate of the two groups was statistically significant (p < 0.05), and the patients' hair conditions in the Group B improved significantly compared with those in the Group A. After 6 months of treatment, the difference in treatment satisfaction between the two groups was statistically significant (p < 0.05). The patients in the Group B were more satisfied than those in Group A. During the patient's medication, no serious adverse reactions occurred in the two groups, and the incidence of adverse reactions between the two groups was not statistically significant (p > 0.05).

CONCLUSION

Compared with 5% minoxidil alone, the combination of basic fibroblast growth factor (bFGF) +5% minoxidil in the treatment of male patients with early stage of androgenetic alopecia improved treatment efficiency and patient satisfaction.

Back to the Future: From Appendage Development Toward Future Human Hair Follicle Neogenesis

Hair disorders such as alopecia and hirsutism often impact the social and psychological well-being of an individual. This also holds true for patients with severe burns who have lost their hair follicles (HFs). HFs stimulate proper wound healing and prevent scar formation; thus, HF research can benefit numerous patients. Although hair development and hair disorders are intensively studied, human HF development has not been fully elucidated. Research on human fetal material is often subject to restrictions, and thus development, disease, and wound healing studies remain largely dependent on time-consuming and costly animal studies. Although animal experiments have yielded considerable and useful information, it is increasingly recognized that significant differences exist between animal and human skin and that it is important to obtain meaningful human models. Human disease specific models could therefore play a key role in future therapy. To this end, hair organoids or hair-bearing skin-on-chip created from the patient’s own cells can be used. To create such a complex 3D structure, knowledge of hair genesis, i.e., the early developmental process, is indispensable. Thus, uncovering the mechanisms underlying how HF progenitor cells within human fetal skin form hair buds and subsequently HFs is of interest. Organoid studies have shown that nearly all organs can be recapitulated as mini-organs by mimicking embryonic conditions and utilizing the relevant morphogens and extracellular matrix (ECM) proteins. Therefore, knowledge of the cellular and ECM proteins in the skin of human fetuses is critical to understand the evolution of epithelial tissues, including skin appendages. This review aims to provide an overview of our current understanding of the cellular changes occurring during human skin and HF development. We further discuss the potential implementation of this knowledge in establishing a human in vitro model of a full skin substitute containing hair follicles and the subsequent translation to clinical use.

HaCaT‑conditioned medium supplemented with the small molecule inhibitors SB431542 and CHIR99021 and the growth factor PDGF‑AA prevents the dedifferentiation of dermal papilla cells in vitro

Hair loss, including alopecia, is a common and distressing problem for men and women, and as a result, there is considerable interest in developing treatments that can prevent or reverse hair loss. Dermal papillae closely interact with epidermal cells and play a key role during hair follicle induction and hair morphogenesis. As dermal papilla cells (DPCs) lose their hair‑inducing ability in monolayer cultures in vitro, it is difficult to obtain de novo hair follicle structures following DPC transplantation in vivo. The present study aimed to explore culture conditions to maintain DPC characteristics using conditioned media (CM) from the supernatant of cultured HaCaT keratinocyte cells supplemented with other components. Initially, it was observed that during passaging of in vitro monolayer DPC cultures, the Wnt/β‑catenin pathway was repressed, while the TGF‑β/Smad pathway was activated, and that HaCaT cells cultivated in 1% fetal bovine serum had higher levels of expression of Wnt3a and Wnt10b compared with normal keratinocytes. Culturing of high‑passage (P7) DPCs in CM from HaCaT cells (HaCaT‑CM) actively stimulated cell proliferation and maintained Sox2 and Versican expression levels. Supplementation of HaCaT‑CM with SB431542 (SB, a TGF‑β receptor inhibitor), CHIR99021, (CHIR, a GSK3α/β inhibitor and activator of Wnt signaling) and platelet‑derived growth factor (PDGF)‑AA further increased the expression levels of Sox2, Versican and alkaline phosphatase (ALP) in P7 DPCs. Three‑dimensional culture of P7 DPCs using hanging drop cultures in HaCaT‑CM supplemented with SB, CHIR and PDGF‑AA resulted in larger cell aggregates and a further significant upregulation of Sox2, ALP and Versican expression levels. Taken together, these findings demonstrated that HaCaT‑CM supplemented with SB, CHIR and PDGF‑AA may preserve the hair‑inducing ability of high‑passage DPCs and may therefore be useful in reconstructing new hair follicles in vivo.

Overexpression of Fgf8 in the epidermis inhibits hair follicle development

The hair follicle is a classical model for studying epithelial-mesenchymal interactions. Given the critical role of fibroblast growth factor 8 (Fgf8) in embryonic development, we generated a mouse model that overexpresses Fgf8 specifically in the epidermis. Interestingly, these mutant mice exhibited stunted, smaller bodies and severe hypotrichosis. Histological analysis showed that the hair follicles in the mutants were arrested at stage 2 of hair development. The density of hair follicles in the mutant mice was also lower compared to that in the control mice. Overexpression of Fgf8 inhibited the proliferation of epidermal cells and simultaneously promoted apoptosis, leading to the arrest of hair follicle development. Further analysis showed that sonic hedgehog (Shh) and bone morphogenetic protein 4 (Bmp4) were downregulated and upregulated, respectively. To summarize, our study demonstrates that FGF signalling plays an important role in the regulation of hair follicle development.

Altered FGF expression profile in human scalp-derived fibroblasts upon WNT activation: implication of their role to provide folliculogenetic microenvironment

Background

Hair follicle (HF) formation and growth are sustained by epithelial-mesenchymal interaction via growth factors and cytokines. Pivotal roles of FGFs on HF regeneration and neogenesis have been reported mainly in rodent models. FGF expression is regulated by upstream pathways, represented by canonical WNT signaling; however, how FGFs influence on human folliculogenesis remains elusive. The aim of this study is to assess if human scalp-derived fibroblasts (sFBs) are able to modulate their FGF expression profile in response to WNT activation and to evaluate the influence of WNT-activated or suppressed FGFs on folliculogenesis.

Methods

Dermal papilla cells (DPCs), dermal sheath cells (DSCs), and sFBs were isolated from the human scalp and cultured independently. The gene expression profile of FGFs in DPCs, DSCs, and sFBs and the influence of WNT activator, CHIR99021, on FGF expression pattern in sFBs were evaluated by reverse transcription polymerase chain reaction, which were confirmed at protein level by western blotting analysis. The changes in the expression of DPC or keratinocyte (KC) biomarkers under the presence of FGF7 or 9 were examined in both single and co-culture assay of DPCs and/or KCs. The influence of FGF 7 and FGF 9 on hair morphogenesis and growth was analyzed in vivo using mouse chamber assay.

Results

In single culture, sFBs were distinguished from DPCs and DSCs by relatively high expression of FGF5 and FGF18, potential inducers of hair cycle retardation or catagen phase. In WNT-activated state, sFBs downregulated FGF7 while upregulating FGF9, a positive regulator of HF morphogenesis, FGF16 and FGF20 belonging to the same FGF subfamily. In addition, CHIR99021, a WNT activator, dose-dependently modulated FGF7 and 9 expression to be folliculogenic. Altered expressions of FGF7 and FGF9 by CHIR99021 were confirmed at protein level. Supplementation of FGF9 to cultured DPCs resulted in upregulation of representative DP biomarkers and this tendency was sustained, when DPCs were co-cultured with KCs. In mouse chamber assay, FGF9 increased both the number and the diameter of newly formed HFs, while FGF7 decreased HF diameter.

Conclusion

The results implied that sFBs support HF formation by modulating regional FGF expression profile responding to WNT activation.

Nanoscale microenvironment engineering based on layer-by-layer self-assembly to regulate hair follicle stem cell fate for regenerative medicine

Hair regenerative medicine, a promising strategy for the treatment of hair loss, will likely involve the transplantation of autologous hair follicular stem cells (HFSCs) and dermal papilla cells (DPCs) into regions of hair loss. Cyclic hair regeneration results from the periodic partial activation of HFSCs. However, previous studies have not successfully achieved large-scale HFSC expansion in vitro without the use of feeder cells, with a lack of research focused on regulating HFSC fate for hair follicular (HF) regeneration. Hence, an emerging focus in regenerative medicine is the reconstruction of natural extracellular matrix (ECM) regulatory characteristics using biomaterials to generate cellular microenvironments for expanding stem cells and directing their fate for tissue regeneration.

Methods: HFSCs were coated with gelatin and alginate using layer-by-layer (LbL) self-assembly technology to construct biomimetic ECM for HFSCs; after which transforming growth factor (TGF)-β2 was loaded into the coating layer, which served as a sustained-release signal molecule to regulate the fate of HFSCs both in vitro and in vivo. In vitro experiments (cell culture and siRNA) were employed to investigate the molecular mechanisms involved and in vivo implantation was carried out to evaluate hair induction efficiency.

Results: Nanoscale biomimetic ECM was constructed for individual HFSCs, which allowed for the stable amplification of HFSCs and maintenance of their stem cell properties. TGF-β2 loading into the coating layer induced transformation of CD34⁺ stem cells into highly proliferating Lgr5⁺ stem cells, similar to the partial activation of HFSCs in HF regeneration. Thus, LbL coating and TGF-β2 loading partially reconstructed the quiescent and activated states, respectively, of stem cells during HF regeneration, thereby mimicking the microenvironment that regulates stem cell fate for tissue regeneration during HF cycling. Improved HF regeneration was achieved when the two HFSC states were co-transplanted with neonatal mouse dermal cells into nude mice.

Conclusion: This study provides novel methods for the construction of stem cell microenvironments and experimental models of HF regeneration for the treatment of hair loss.

Expression Profiling and Functional Characterization of miR-26a and miR-130a in Regulating Zhongwei Goat Hair Development via the TGF-β/SMAD Pathway

The Zhongwei goat is an important and unique goat breed indigenous to China. It has a natural hair curling phenotype at birth, but the degree of curling gradually decreases with growth. The molecular mechanism underlying the dynamic changes in the wool curvature in Zhongwei goats is poorly understood. MicroRNAs (miRNAs) play important roles in many biological processes, including hair growth and development. In this study, we selected skins from Zhongwei goats at different ages (45 and 108 days) that exhibited different levels of hair curvature and performed miRNA sequencing to explore the molecular mechanism of hair bending. In total, 28 significantly differentially expressed miRNAs (DE miRNAs) were identified in the three groups of samples between the two developmental stages. An analysis of the target genes of the above-mentioned DE miRNAs by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that the DE miRNAs were involved in signal pathways which were previously associated with hair bending and hair follicle development, such as the TGF-β/SMAD, PI3K-Akt, JAK-STAT, and MAPK pathways. A comprehensive analysis of the correlations between the miRNA-seq results and issued transcriptional findings indicated that SMAD1 was a target gene of miR-26a and SMAD5 was a target gene of miR-130a. Furthermore, goat dermal papilla cells were successfully isolated and purified to determine the role of miRNAs in follicle development in vitro. The study results demonstrated that miR-130a and miR-26a had significant effects on the proliferation of dermal papilla cells. In addition, the detection results of mRNA and protein levels indicate that the overexpression of miR-26a can promote the expression of related genes in the TGF-β/SMAD pathway, while miR-130a has the opposite substitution effect. The dual luciferase report test showed that miR-26a targeted the SMAD1 gene and reduced the expression of the SMAD1 protein in hair papillary cells. Our results identified DE microRNAs which perhaps change at the time of hair straightening in Zhongwei goats and explore the role of miR-26a and miR-130a in dermal papilla cells proliferation. The present study provided a theoretical basis to explore the mechanisms underlying the Zhongwei hair growth and curly phenotype.

Characterization and functional analysis of SIAH1 during skin and hair follicle development in the angora rabbit (Oryctolagus cuniculus)

BACKGROUND

Seven in absentia homolog 1 (SIAH1) is an E3 ubiquitin ligase containing a RING-finger domain and a key regulator of normal development. Skin and hair follicle development is a complex and special process of morphogenesis involving multiple signaling pathways. SIAH1 is enriched in the Wnt signaling pathway and potentially related to hair follicle cycle and skin development. This study aims to provide evidence for the role of SIAH1 in skin and hair development.

RESULTS

Full-length cloning and analysis of SIAH1 was conducted to better understand its function. Phylogenetically, the sequence of SIAH1 in the rabbit shares the greatest homology with Home sapiens, Pongo abelii and Mus mulatta. Based on the rabbit hair follicle synchronization model, we found that the expression level of SIAH1 in the regressive period of the rabbit hair cycle is significantly lower than in the active growth and rest periods. In addition, the mRNA expression levels of skin and hair follicle development-related genes changed significantly when SIAH1 was overexpressed and silenced. After SIAH1 overexpression, the expression levels of WNT2, LEF1 and FGF2 decreased, and those of SFRP2 and DKK1 increased (P < 0.05). After interference of SIAH1, the expression levels of WNT2, LEF1 and FGF2 increased (P < 0.05), and SFRP2 and DKK1 decreased.

CONCLUSIONS

SIAH1 can affect skin and hair follicle development and exert an inhibitory effect. These results could provide foundamental insights into the role of SIAH1 as a target gene in rabbit skin and hair follicle development.

Extremely Low-Frequency Electromagnetic Fields Increase the Expression of Anagen-Related Molecules in Human Dermal Papilla Cells via GSK-3β/ERK/Akt Signaling Pathway

Despite advances in medical treatments, the proportion of the population suffering from alopecia is increasing, thereby creating a need for new treatments to control hair loss and prevent balding. Human hair follicle dermal papilla cells (hDPCs), a type of specialized fibroblast in the hair bulb, play an essential role in controlling hair growth and in conditions like androgenic alopecia. This study aimed to evaluate the intensity-dependent effect of extremely low-frequency electromagnetic fields (ELF-EMFs) on the expression of anagen-related molecules in hDPCs in vitro. We examined the effect of ELF-EMF on hDPCs to determine whether activation of the GSK-3β/ERK/Akt signaling pathway improved hDPC activation and proliferation; hDPCs were exposed to ELF-EMFs at a frequency of 70 Hz and at intensities ranging from 5 to 100 G, over four days. Various PEMF intensities significantly increased the expression of anagen-related molecules, including collagen IV, laminin, ALP, and versican. In particular, an intensity of 10 G is most potent for promoting the proliferation of hDPC and expression of anagen-related molecules. Moreover, 10 G ELF-EMF significantly increased β-catenin and Wnt3α expression and GSK-3β/ERK/Akt phosphorylation. Our results confirmed that ELF-EMFs enhance hDPC activation and proliferation via the GSK-3β/ERK/Akt signaling pathway, suggesting a potential treatment strategy for alopecia.

Optimal stimulation toward the dermal papilla lineage can be promoted by combined use of osteogenic and adipogenic inducers

Dermal papilla cells (DPCs) play crucial roles in hair regeneration, but they readily lose their hair‐forming ability during in vitro culture. Although the formation of spheroids partially restores the ability, shrinkage of the spheroids makes it difficult to maintain cellular viability. To address this problem, we stimulated DPCs with factors known to induce adipogenic and/or osteogenic differentiation, because DPCs share unique gene expression profiles with adipocytes and osteocytes. We isolated DPCs from versican (vcan)–GFP mice, in which GFP is expressed under the control of a vcan promoter, which is strongly active in DPCs of anagen hair follicles. GFP fluorescence was most intense when the spheroids were made from DPCs cultured in a half‐diluted combination of adipogenic and osteogenic media (CAO1/2), a Dulbecco’s modified Eagle’s medium‐based medium that contains 10% FBS, 275 nm dexamethasone, 2.5 mm β‐glycerol phosphate, 12.5 µg·mL⁻¹ ascorbic acid, 0.125 µm isobutylmethylxanthine and 2.5 ng·mL⁻¹ insulin. The dose of each additive used was less than the optimal dose for adipogenic or osteogenic differentiation, and shrinkage of the spheroids was avoided through the addition of fibroblast growth factor 2 and platelet‐derived growth factor‐AA to  CAO1/2. In addition, the gene and protein expression of vcan, osteopontin, alkaline phosphatase and α‐smooth muscle actin in the spheroids were augmented to levels similar to those of the intact dermal papillae, which exhibited restored hair‐forming activity. In conclusion, a combination of certain adipogenic and osteogenic inducers, together with fibroblast growth factor 2 and platelet‐derived growth factor‐AA, can promote differentiation toward the DPC lineage.

Use of extracellular matrix hydrogel from human placenta to restore hair-inductive potential of dermal papilla cells

Aim: To explore the feasibility of human placenta extracellular matrix (HPECM) hydrogel in restoring the hair-inductive capacity of high-passaged (P8) dermal papilla cells (DPCs) for hair follicle regeneration. Materials & methods: HPECM hydrogel was prepared following decellularization and enzymatic solubilization treatment. DPCs isolated from human scalp were cultured in 2D and 3D environments. The hair-inductive ability of DPCs was assessed by quantitative RT-PCR, immunofluorescence staining, immunoblotting and patch assay. Results: DPCs (P8) formed spheres when cultured on the HPECM hydrogel. The expression levels of Versican, ALP, and β-catenin were restored in the DP spheres. HPECM hydrogel-cultured DP spheres co-grafted with newborn mouse epidermal cells regenerated new hair follicle. Conclusion: HPECM hydrogel successfully restores the hair-inductive capacity of high-passaged DPCs.

Advances in Regenerative Stem Cell Therapy in Androgenic Alopecia and Hair Loss: Wnt pathway, Growth-Factor, and Mesenchymal Stem Cell Signaling Impact Analysis on Cell Growth and Hair Follicle Development

The use of stem cells has been reported to improve hair regrowth in several therapeutic strategies, including reversing the pathological mechanisms, that contribute to hair loss, regeneration of hair follicles, or creating hair using the tissue-engineering approach. Although various promising stem cell approaches are progressing via pre-clinical models to clinical trials, intraoperative stem cell treatments with a one-step procedure offer a quicker result by incorporating an autologous cell source without manipulation, which may be injected by surgeons through a well-established clinical practice. Many authors have concentrated on adipose-derived stromal vascular cells due to their ability to separate into numerous cell genealogies, platelet-rich plasma for its ability to enhance cell multiplication and neo-angiogenesis, as well as human follicle mesenchymal stem cells. In this paper, the significant improvements in intraoperative stem cell approaches, from in vivo models to clinical investigations, are reviewed. The potential regenerative instruments and functions of various cell populaces in the hair regrowth process are discussed. The addition of Wnt signaling in dermal papilla cells is considered a key factor in stimulating hair growth. Mesenchymal stem cell-derived signaling and growth factors obtained by platelets influence hair growth through cellular proliferation to prolong the anagen phase (FGF-7), induce cell growth (ERK activation), stimulate hair follicle development (β-catenin), and suppress apoptotic cues (Bcl-2 release and Akt activation).

Preparation of hair beads and hair follicle germs for regenerative medicine

Hair regenerative medicine is a promising approach for hair loss, during which autologous follicular stem cells are transplanted into regions of hair loss to regenerate hairs. Because cells transplanted as a single cell suspension scarcely generate hairs, the engineering of three-dimensional (3D) tissues before transplantation has been explored to improve this process. Here, we propose an approach to fabricate collagen-enriched cell aggregates, named hair beads (HBs), through the spontaneous constriction of cell-encapsulated collagen drops. Mouse embryonic mesenchymal cells or human dermal papilla cells were encapsulated in 2-μl collagen microgels, which were concentrated >10-fold in volume during 3 days of culture. Interestingly, HB constriction was attributed to attraction forces driven by myosin II and involved the upregulation of follicular genes. Single HBs with epithelial cells seeded in U-shaped microwells formed dumbbell-like structures comprising respective aggregates (named bead-based hair follicle germs, bbHFGs), during 3 days of culture. bbHFGs efficiently generated hair follicles upon intracutaneous transplantation into the backs of nude mice. Using an automated spotter, this approach was scalable to prepare a large number of bbHFGs, which is important for clinical applications. Therefore, this could represent a robust and practical approach for the preparation of germ-like tissues for hair regenerative medicine.

Platelet-Rich Plasma and Micrografts Enriched with Autologous Human Follicle Mesenchymal Stem Cells Improve Hair Re-Growth in Androgenetic Alopecia. Biomolecular Pathway Analysis and Clinical Evaluation

Platelet rich plasma (PRP) and Micrografts containing human follicle mesenchymal stem cells (HF-MSCs) were tried as a potential treatment for androgenetic alopecia (AGA). However, little to no work has yet to be seen wherein the bio-molecular pathway of HF-MSCs or PRP treatments were analyzed. The aims of this work are to report the clinical effectiveness of HF-MSCs and platelet-rich plasma evaluating and reviewing the most updated information related to the bio-molecular pathway. Twenty-one patients were treated with HF-MSCs injections and 57 patients were treated with A-PRP. The Wnt pathway and Platelet derived-growth factors effects were analyzed. 23 weeks after the last treatment with mean hair thickness increments (29 ± 5.0%) over baseline values for the targeted area. 12 weeks after the last injection with A-PRP mean hair count and hair density (31 ± 2%) increases significantly over baseline values. The increment of Wnt signaling in Dermal Papilla Cells evidently is one of the principal factors that enhances hair growth. Signaling from mesenchymal stem cells and platelet derived growth factors positively influences hair growth through cellular proliferation to prolong the anagen phase (FGF-7), inducing cell growth (ERK activation), stimulating hair follicle development (β-catenin), and suppressing apoptotic cues (Bcl-2 release and Akt activation).

PDGFA in Cashmere Goat: A Motivation for the Hair Follicle Stem Cells to Activate

The cashmere hair follicle (HF) perpetually goes through cycles of growth, involution and rest. The photoperiod is the main factor in the control of seasonal coat change in cashmere goats while stem cells play a crucial role in the HF growth. Several factors, including Platelet-Derived Growth Factor A (PDGFA), Bone Morphogenetic Protein 2 (BMP2) and Lim-Homeobox gene 2 (LHX2) are implicated in HF morphogenesis and cycle. In this work, the mentioned molecules were investigated to evaluate their role in follicular cycle activation. The study was performed on skin samples collected at different periods of HF cycle and the molecular expression of PDGFA, BMP2 and LHX2 was evaluated by Real-Time PCR (qPCR) at each time point. Since PDGFA showed the most variation, the goat PDGFA gene was sequenced and the protein localization was investigated by immunohistochemistry together with PDGF receptor α (PDGFRα). PDGFA immunostaining was observed in the basal layer of the HF outer root sheath and the immunoreaction appeared stronger in the regressive HFs compared to those in the anagen phase according to qPCR analysis. PDGFRα was observed in the HF epithelium, proving the effect of PDGFA on the follicular structure. The data obtained suggest that PDGFA and BMP2 are both implicated in HF cycle in goat. In particular, PDGFA secreted by the HF is involved in the anagen activation.

Review of Hair Follicle Dermal Papilla cells as in vitro screening model for hair growth

Hair disorders such as hair loss (alopecia) and androgen dependent, excessive hair growth (hirsutism, hypertrichosis) may impact the social and psychological well-being of an individual. Recent advances in understanding the biology of hair have accelerated the research and development of novel therapeutic and cosmetic hair growth agents. Preclinical models aid in dermocosmetic efficacy testing and claim substantiation of hair growth modulators. The in vitro models to investigate hair growth utilize the hair follicle Dermal Papilla cells (DPCs), specialized mesenchymal cells located at the base of hair follicle that play essential roles in hair follicular morphogenesis and postnatal hair growth cycles. In this review, we have compiled and discussed the extensively reported literature citing DPCs as in vitro model to study hair growth promoting and inhibitory effects. A variety of agents such as herbal and natural extracts, growth factors and cytokines, platelet-rich plasma, placental extract, stem cells and conditioned medium, peptides, hormones, lipid-nanocarrier, light, electrical and electromagnetic field stimulation, androgens and their analogs, stress-serum and chemotherapeutic agents etc. have been examined for their hair growth modulating effects in DPCs. Effects on DPCs' activity were determined from untreated (basal) or stress induced levels. Cell proliferation, apoptosis and secretion of growth factors were included as primary end-point markers. Effects on a wide range of biomolecules and mechanistic pathways that play key role in the biology of hair growth were also investigated. This consolidated and comprehensive review summarizes the up-to-date information and understanding regarding DPCs based screening models for hair growth and may be helpful for researchers to select the appropriate assay system and biomarkers. This review highlights the pivotal role of DPCs in the forefront of hair research as screening platforms by providing insights into mechanistic action at cellular level, which may further direct the development of novel hair growth modulators.

Hair-Shaft Growth in Gelfoam® Histoculture of Skin and Isolated Hair Follicles

Human scalp skin with abundant hair follicles in various stages of the hair growth cycle was histocultured for up to 40 days on Gelfoam^® at the air/liquid interface. The anagen hair follicles within the histoculture scalp skin produced growing hair shafts. Hair follicles could continue their cycle in histoculture; for example, apparent spontaneous catagen induction was observed both histologically and by the actual regression of the hair follicle. In addition, vellus follicles were shown to be viable at day 40 after initiation of culture. Follicle keratinocytes continued to incorporate [³H]thymidine for up to several weeks after shaft elongation had ceased. Intensive hair growth was observed in the pieces of shaved mouse skin histocultured on Gelfoam^®. Isolated human and mouse hair follicles also produced growing hair shafts. By day 63 in histoculture of mouse hair follicles, the number of hair follicle-associated pluripotent (HAP) stem cells increased significantly and the follicles were intact. Gelfoam^® histoculture of skin demonstrated that the hair follicle cells are the most sensitive to doxorubicin which prevented hair growth, thereby mimicking chemotherapy-induced alopecia in Gelfoam^® histoculture.

As a carrier-transporter for hair follicle reconstitution, platelet-rich plasma promotes proliferation and induction of mouse dermal papilla cells

Morphogenesis of hair follicles during development and in hair reconstitution assays involves complex interactions between epithelial cells and dermal papilla cells (DPCs). DPCs may be a source of cells for hair regeneration in alopecia patients. Reconstitution of engineered hair follicles requires in vitro culture of trichogenic cells, a three-dimensional scaffolds, and biomolecular signals. However, DPCs tend to lose their biological activity when cultured as trichogenic cells, and scaffolds currently used for hair follicle regeneration lack biological efficiency and biocompatibility. Platelet-rich plasma (PRP) gel forms a three-dimensional scaffold that can release endogenous growth factors, is mitogenic for a variety of cell types and is used in model tissue repair and regeneration systems. We found that 5% activated PRP significantly enhanced cell proliferation and hair-inductive capability of mouse and human DPCs in vitro and promoted mouse hair follicle formation in vivo. PRP also formed a three-dimensional gel after activation. We used PRP gel as a scaffold to form many de novo hair follicles on a plane surface, showing it to be candidate bioactive scaffold capable of releasing endogenous growth factors for cell-based hair follicle regeneration.

Evaluation of Not-Activated and Activated PRP in Hair Loss Treatment: Role of Growth Factor and Cytokine Concentrations Obtained by Different Collection Systems

Platelet rich plasma (PRP) was tested as a potential therapy for androgenetic alopecia (AGA) through two different clinical protocols in which one population (18 participants) received half-head treatment with autologous non-activated PRP (A-PRP) produced by CPunT Preparation System (Biomed Device, Modena, Italy) and the other half-head with placebo, and a second separated population in which all participants (n = 6, 3 participants per group) received treatment with calcium-activated PRP (AA-PRP) produced from one of two different PRP collection devices (Regen Blood Cell Therapy or Arthrex Angel System). For the A-PRP study, three treatments were administered over 30-day intervals. Trichoscan analysis of patients, three months post-treatment, showed a clinical improvement in the number of hairs in the target area (36 ± 3 hairs) and in total hair density (65 ± 5 hair cm²), whereas negligible improvements in hair count (1.1 ± 1.4 hairs) and density (1.9 ± 10.2 hair cm²) were seen in the region of the scalp that received placebo. Microscopic evaluation conducted two weeks after treatment showed also an increase in epidermal thickness, Ki67⁺ keratinocytes, and in the number of follicles. The AA-PRP treatment groups received a singular set of injections, and six months after the treatments were administered, notable differences in clinical outcomes were obtained from the two PRP collection devices (+90 ± 6 hair cm² versus −73 ± 30 hair cm² hair densities, Regen versus Arthrex). Growth factor concentrations in AA-PRP prepared from the two collection devices did not differ significantly upon calcium activation.

Cytokine loaded layer-by-layer ultrathin matrices to deliver single dermal papilla cells for spot-by-spot hair follicle regeneration

Polymer nanocoated dermal papilla cells promoting hair regeneration.