Stem cells and alopecia: a review of pathogenesis

The value of immunohistochemical expression of SOX9 and CD34 in alopecia areata

BACKGROUND

Alopecia areata (AA), an immune-mediated disorder, is marked by temporary, nonscarring hair loss. The bulge area is protected from immune attacks by immune privilege; however, recent studies demonstrated immune cells infiltrating the bulge area.

OBJECTIVE

This study aims to investigate the immunohistochemical expression of the sex-determining region Y-box 9 (SOX9) and cluster of differentiation 34 (CD34) in AA patients as markers of hair follicle stem cells (HFSCs) and progenitor cells, respectively.

METHODS

Immunohistochemical staining of SOX9 and CD34 was applied on skin samples of 20 AA patients and 20 healthy controls.

RESULTS

SOX9 and CD34 were significantly lower in lesional samples of cases compared to perilesional and control skin biopsies. Furthermore, SOX9 level was negatively correlated with the severity of alopecia tool score (SALT score) among the studied AA patients. Moreover, lowered SOX9 expression was present in patients with recurrent attacks.

CONCLUSIONS

The significant reduction of stem cell markers (SOX9 and CD34) in our studied AA cases signifies the pathological affection of HFSCs and their progeny in AA. This is thought to cause a loss of competence in generating new hair in some AA cases, which needs to be validated in further research.

LIMITATIONS OF THE STUDY

This study has a small sample size.

Two-dimensional planimetry for alopecia areata severity evaluation compared with severity of alopecia tool: A pilot study

BACKGROUND

Severity of Alopecia Tool (SALT) is widely used to assess the severity of alopecia areata (AA). However, physician-related subjectivity exists in SALT scoring (S1-5), especially with initial inspection in the clinical practice. This study investigated two-dimensional planimetric method to calculate actual surface area of AA, validating SALT scoring.

MATERIALS AND METHODS

SALT score was measured twice in each patient based on "initial" inspection in the clinic (SALT-I) and retrospective assessment of the "photograph" (SALT-P). Planimetric surface area was calculated by Image J program. Subgroup analysis was performed depending on the agreement between SALT-I and -P; score was described in the order of SALT-I and SALT-P.

RESULTS

A total of 93 subjects were enrolled. Planimetric surface area (cm2 ) of SALT-I was 2.5-74.9 (S1), 48.8-100.6 (S2), 83.6-205.4 (S3), and 282-367.9 (S4), while SALT-P was 2.5-59.2 (S1), 41.6-205.4 (S2), 48.8-183.2 (S3), and 282-367.9 (S4). In subgroup analysis, SALT-I and SALT-P agreed group showed planimetric surface area (cm2 ) as 2.5-59.2 (S1-1), 64.2-100.6 (S2-2), 168.3-183 (S3-3), and 282.6-367.9 (S4-4). Disagreed group showed the value as 54.7 (S1-2), 41.6-74.9 (S2-1), 83.6-205.4 (S2-3), and 48.8-88.6 (S3-2).

CONCLUSION

SALT-P was more clearly correlated with actual surface area than SALT-I. Planimetric surface area measurement could be used as a supplementary method especially in the S1 to S3, suggesting 60 cm2 , 100 cm2 , and 200 cm2 as objective cutoff values to differentiate S1, S2, and S3.

From Hair to Colon: Hair Follicle-Derived MSCs Alleviate Pyroptosis in DSS-Induced Ulcerative Colitis by Releasing Exosomes in a Paracrine Manner

Ulcerative colitis (UC) has attracted intense attention due to its high recurrence rate and the difficulty of treatment. Pyroptosis has been suggested to be crucial in the development of UC. Although mesenchymal stem cells (MSCs) are broadly used for UC therapy, they have rarely been studied in the context of UC pyroptosis. Hair follicle-derived MSCs (HFMSCs) are especially understudied with regard to UC and pyroptosis. In this study, we aimed to discover the effects and potential mechanisms of HFMSCs in UC. We administered HFMSCs to dextran sulfate sodium- (DSS-) treated mice and found that the HFMSCs significantly inhibited pyroptosis to alleviate DSS-induced UC. A transwell system and GW4869, an exosome inhibitor, were used to prove the paracrine mechanism of HFMSCs. HFMSC supernatant reduced pyroptosis-related protein expression and promoted cell viability, but these effects were attenuated by GW4869, suggesting a role for HFMSC-released exosomes (Exos) in pyroptosis. Next, Exos were extracted and administered in vitro and in vivo to explore their roles in pyroptosis and UC. In addition, the biodistribution of Exos in mice was tracked using an imaging system and immunofluorescence. The results suggested that Exos not only improved DSS-induced pyroptosis and UC but also were internalized into the injured colon. Furthermore, the therapeutic efficacy of Exos was dose dependent. Among the Exo treatments, administration of 400 μg of Exos per mouse twice a week exhibited the highest efficacy. The differentially expressed miRNAs (DEmiRNAs) between MSCs and MSC-released Exos suggested that Exos might inhibit pyroptosis through tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) signalling and interferon- (IFN-) gamma pathways. Our study reveals that HFMSCs can alleviate pyroptosis in UC by releasing DEmiRNA-containing Exos in a paracrine manner. This finding may lead to new treatments for UC.

Hair follicle-derived mesenchymal stem cells decrease alopecia areata mouse hair loss and reduce inflammation around the hair follicle

Background

Alopecia areata (AA) is a common autoimmune hair loss disease with increasing incidence. Corticosteroids are the most widely used for hair loss treatment; however, long-term usage of hormonal drugs is associated with various side effects. Mesenchymal stem cells (MSCs) therapy has been studied extensively to curb autoimmune diseases without affecting immunity against diseases.

Methods

Hair follicle-derived MSCs (HF-MSCs) were harvested from the waste material of hair transplants, isolated and expanded. The therapeutic effect of HF-MSCs for AA treatment was investigated in vitro AA-like hair follicle organ model and in vivo C3H/HeJ AA mice model.

Results

AA-like hair follicle organ in vitro model was successfully established by pre-treatment of mouse vibrissa follicles by interferon-γ (IFN-γ). The AA-like symptoms were relieved when IFN-γ induced AA in vitro model was co-cultured with HF-MSC for 2 days. In addition, when skin grafted C3H/HeJ AA mice models were injected with 10⁶ HF-MSCs once a week for 3 weeks, the transcription profiling and immunofluorescence analysis depicted that HF-MSCs treatment significantly decreased mouse hair loss and reduced inflammation around HF both in vitro and in vivo.

Conclusions

This study provides a new therapeutic approach for alopecia areata based on HF-MSCs toward its future clinical application.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02614-0.

A systematic summary of survival and death signalling during the life of hair follicle stem cells

Hair follicle stem cells (HFSCs) are among the most widely available resources and most frequently approved model systems used for studying adult stem cells. HFSCs are particularly useful because of their self-renewal and differentiation properties. Additionally, the cyclic growth of hair follicles is driven by HFSCs. There are high expectations for the use of HFSCs as favourable systems for studying the molecular mechanisms that contribute to HFSC identification and can be applied to hair loss therapy, such as the activation or regeneration of hair follicles, and to the generation of hair using a tissue-engineering strategy. A variety of molecules are involved in the networks that critically regulate the fate of HFSCs, such as factors in hair follicle growth and development (in the Wnt pathway, Sonic hedgehog pathway, Notch pathway, and BMP pathway), and that suppress apoptotic cues (the apoptosis pathway). Here, we review the life cycle, biomarkers and functions of HFSCs, concluding with a summary of the signalling pathways involved in HFSC fate for promoting better understanding of the pathophysiological changes in the HFSC niche. Importantly, we highlight the potential mechanisms underlying the therapeutic targets involved in pathways associated with the treatment of hair loss and other disorders of skin and hair, including alopecia, skin cancer, skin inflammation, and skin wound healing.

An updated review of the sebaceous gland and its role in health and diseases Part 2: Pathophysiological clinical disorders of sebaceous glands

Sebaceous glands are sebum-secreting components of pilosebaceous units. In the second of this two-part series, we review the pathologies in which sebaceous glands are primarily and secondarily implicated. They are primarily involved in steatocystoma simplex and multiplex, sebaceous gland hyperplasia, sebaceoma, sebaceous adenoma, sebaceous carcinoma, nevus sebaceus, and folliculosebaceous cystic hamartoma. Sebaceous glands are secondarily involved in acne vulgaris, seborrheic dermatitis, and androgenic alopecia. Steatocystoma multiplex is a benign congenital anomaly presenting as yellow cysts primarily on the upper body. Sebaceous gland hyperplasia is characterized by yellow, telangiectatic papules with a central dell, and it can be treated with topical retinoids or surgical excision. Sebaceoma clinically presents on the head and neck region as a skin-colored nodule and can be distinguished by immunohistochemistry. Stains used in the diagnosis of sebaceous adenoma and carcinoma include epithelial membrane antigen and adipophilin immunoperoxidase. Surgical excision is the preferred treatment for sebaceoma, sebaceous adenoma, and sebaceous carcinoma. Excision is not always indicated for nevus sebaceus. Folliculosebaceous cystic hamartoma is a relatively rare condition exhibiting both epithelial and mesenchymal components. Patients with acne vulgaris commonly present with papules of closed and open comedones displaying hypercornification. Seborrheic dermatitis presents as sharply demarcated yellow or red patches or plaques; antifungal agents, corticosteroids, and combination antifungal/anti-inflammatory therapies are common treatment modalities. As a result of hair follicle miniaturization, females with androgenic alopecia present with diffuse hair thinning, while men tend to present with balding and hairline recession.

Immunology of alopecia areata

Alopecia areata is a condition that affects hair follicles and leads to hair loss ranging from small well-defined patches to complete loss of all body hair. Despite its high incidence, the pathobiology is not fully understood, and no single concept could be universally accepted.

Alopecia areata is mostly considered to be an autoimmune disease, in which the collapse of hair follicle immune privilege plays a key role. Higher incidence rate in the female population and increased overall risk of other autoimmune disorders militate in favor of autoimmune hypothesis. Antibodies against multiple components of hair follicles almost exclusively attack in anagen phase, where melanogenesis takes place. It suggests involvement of melanogenesis-associated autoantigens as a target epitope.

Some investigators believed that alopecia areata is not a truly autoimmune disease but is only ‘consistent with’ autoimmune mechanisms. High frequency of a positive family history up to 42% may reflects the contribution of heredity factors. In addition, no specific target autoantigen has been identified so far, and autoantibodies to hair follicle-associated antigens are detectable in normal individuals.

Vascular Endothelial Growth Factor Protects CD200-Rich and CD34-Positive Hair Follicle Stem Cells Against Androgen-Induced Apoptosis Through the Phosphoinositide 3-Kinase/Akt Pathway in Patients With Androgenic Alopecia

BACKGROUND

5α-DHT can decrease the cell viability of the hair follicle stem cells (HFSCs) with CD34-positive and CD200-rich in bald scalp area of androgenic alopecia (AGA) patients and the apoptosis of HFSCs may be involved in the pathogenesis of AGA. The expression of Vascular endothelial growth factor (VEGF) turns to be weakened or disappeared in hair follicles of AGA patients.

OBJECTIVE

To investigate whether VEGF is involved in the apoptosis of HFSCs induced by 5α-DHT in the patients of AGA.

METHODS

By 5α-DHT, apoptosis of CD200-rich and CD34-positive HFSCs was induced and apoptotic rates up to 24 hours were assessed using flow cytometry. The expression grades of Bcl-2, Akt, caspase-3 and Bax were observed through Western blot analysis.

RESULTS

Vascular endothelial growth factor could cut 5α-DHT induced apoptosis down substantially in a concentration-dependent manner. The 5α-DHT induced decline in the rise of Bcl-2/Bax proportion and the increase in caspase-3 degrees were mostly reversed by using VEGF and the VEGF's anti-apoptotic actions were impeded through preventing the activation of phosphoinositide 3-kinase (PI3K)/Akt.

CONCLUSION

Vascular endothelial growth factor can protect CD200-rich and CD34-positive HFSCs from androgen induced apoptosis by means of the PI3K/Akt pathway.

Preliminary studies of hair follicle regeneration by injections of epidermal stem cells and dermal papilla cells into nude mice

The ultimate goal of organ regenerative therapy is to reproduce fully functional organs to replace which have been damaged as a result of diseases or injury. Although several studies claimed that using different types of cells in some animal models promote hair follicles regeneration, more researches can be done to develop a sufficient and efficient protocol to induce hair generation from different animal models. In this study, we investigated the therapeutic potentials for hair follicle formation by injecting a mixture of epidermal stem cells and dermal papilla cells. Those cells were isolated and culture-expanded. Then we randomly allocated 8 nude mice into two groups. The experiment group received an injection of a mixture that containing of epidermal stem cells and dermal papilla cells. The control group received injection of keratinocyte serum-free medium. The hair follicles regeneration was observed and the injection area was harvested for HE staining. 14 day later, the regenerated hair shafts were observed and HE staining indicated that the newly hair follicle formed the correct structures in experiment group. Furthermore, the mixture injection induced a regular and multilayered stratified epidermis and the epidermis contained of hair follicle-likes structures. Our data showed that injection of a mixture of epidermal stem cells and dermal papilla cells could induce hair follicles regeneration and well-ordered epidermis formation. This study emphasized that the rearrangement of the interactions during seed cells and the niches of the seed cells is essential and necessary for tissue-engineered construct success.

Compared to Controls, Individuals with Lichen Planopilaris Have More Depression, a Lower Self-Esteem, and a Lower Quality of Life

BACKGROUND

Individuals with lichen planopilaris (LPP) typically present with hair loss and an irritated scalp, with signs and symptoms such as itching, erythema, scaling, and burning. Both hair loss and reddened skin may be visible also for other people. Therefore, it is conceivable that individuals with LPP might report a lower mental health status. Accordingly, in the present study, we compared dimensions of mental health between individuals with LPP and healthy controls.

METHOD

A total of 38 individuals with LPP (mean age: 38.24 years, 47.4% females) and 58 gender- and age-matched controls took part in this study. They completed questionnaires covering dimensions of quality of life and self-esteem; experts rated participants' symptoms of depression and anxiety. Furthermore, dermatologists reported on the illness duration, the LPP activity index, and the severity of alopecia.

RESULTS

Compared to healthy controls, individuals with LPP reported lower scores of self-esteem, physical functioning, and mental health and higher scores of role limitations (physical and emotional). Likewise, experts rated higher depression scores in individuals with LPP compared to controls. In individuals with LPP, a higher LPP disease activity and a higher severity of hair loss were associated with higher depression and lower quality-of-life scores. Further, a higher LPP activity index, a lower self-esteem, and higher anxiety scores predicted a poorer quality of life, while illness duration was statistically unrelated.

CONCLUSIONS

Compared to controls, and irrespectively of the illness duration, individuals with LPP reported a lower quality of life and a lower self-esteem, and experts' ratings observed higher scores of depression. Experts treating individuals with LPP might pay special attention to the individuals' mental health status.

Use of Condensed Nanofat Combined With Fat Grafts to Treat Atrophic Scars

Importance

In addition to the physical deformity, there is often great psychological burden of facial scars for patients. In this study, we use condensed nanofat combined with fat grafts in a novel technique to improve atrophic facial scars by raising both the surface and the bottom of the affected area.

Objective

To assess whether the use of condensed nanofat combined with fat grafting can be effective in treating atrophic facial scars from both an aesthetic and a functional perspective.

Design, Setting, and Participants

In this prospective case series of 20 patients with 25 atrophic facial scars, each scar was treated with condensed nanofat combined with fat grafts at the Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang, China. Postoperative results were evaluated by the patients themselves and by 3 senior plastic surgeon observers.

Main Outcomes and Measures

Multiple preoperative and postoperative examinations included the use of the Patient and Observer Scar Assessment Scale (POSAS) to evaluate both the functional and aesthetic aspects of the atrophic facial scars. Punch biopsy specimens were stained for the presence of melanin, elastic fibers, and cytokeratin (CK) 14 and CK19. Images were analyzed using ImageJ software, and the data were analyzed by paired sample t test.

Results

Twenty patients (6 men and 14 women; mean age, 38.25 years; age range, 21-62 years) with a total of 25 atrophic facial scars were treated between March 2014 and December 2016. The patients' mean (SD) scar assessment scores were significantly decreased postoperatively in the final examination for color, 6.40 (0.51) vs 2.40 (0.24) (P < .001); stiffness, 7.20 (0.37) vs 3.20 (0.20) (P < .001); thickness, 5.80 (0.73) vs 1.80 (0.37) (P = .001); and irregularity, 5.20 (0.49) vs 2.20 (0.37) (P = .003); and the observers' scores were also significantly decreased for pigmentation, 4.40 (0.51) vs 2.00 (0.32) (P = .004); thickness, 3.00 (0.32) vs 1.80 (0.20) (P = .03); relief, 4.40 (0.51) vs 2.40 (0.24) (P = .003); and pliability, 4.20 (0.37) vs 1.40 (0.24) (P < .001). In the final follow-up examinations, a significantly improved overall POSAS score was found among both patients, 28.80 (1.02) vs 12.20 (0.80) (P < .001), and observers, 18.00 (0.71) vs 9.20 (0.37) (P = .001). Enhancement of Fontana-Masson staining of melanin in the basal cell layer was observed postoperatively, and a significant postoperative change was detected for the mean (SD) values of average optical density from the preoperative measurement, 0.671 (0.083) vs 0.844 (0.110) (P = .01). The sebaceous glands and sweat glands that were not found in the preoperative images were seen postoperatively by immunohistochemical staining with CK14 and CK19.

Conclusions and Relevance

Our preliminary clinical and pathological results indicate that the use of condensed nanofat combined with fat grafts may be an effective approach to treating atrophic facial scars from both an aesthetic and a functional perspective.

Level of Evidence

4.

Stem cell therapy as a novel therapeutic intervention for resistant cases of alopecia areata and androgenetic alopecia

BACKGROUND

Management of alopecia areata (AA) and androgenetic alopecia (AGA) is often challenging as patients may be resistant to currently available modalities of treatment. The use of stem cells may be a novel option for resistant cases.

OBJECTIVE

To evaluate the safety and efficacy of the use of autologous bone marrow derived mononuclear cells (including stem cells) as compared to follicular stems cells for the management of resistant cases of AA and AGA.

METHODS

This study included 40 patients (20 AA patients and 20 AGA patients), all patients were treated with a single session of intradermal injection of autologous stem cells (SCs) therapy. They were divided into four groups according to the applied modality [either autologous bone marrow derived mononuclear cells (bone marrow mononuclear cells [BMMCs] or autologous follicular stem cells [FSC]).

RESULTS

Six months after stem cell therapy (SCT) injection, there was a significant improvement, confirmed by immunostaining and digital dermoscopy. The mean improvement in all groups was "very good". There was no significant difference between both methods in either type of alopecia. No serious adverse events were reported.

CONCLUSION

Autologous BMMCs and FSC seem to be a safe tolerable and effective treatment for the management of both resistant AA and AGA.

The Contributory Roles of Th17 Lymphocyte and Cytotoxic T Lymphocyte at the Hair Bulge Region as Well as the Hair Bulb Area in the Chronic Alopecia Areata Patients

BACKGROUND

Alopecia areata (AA) is a T cell-mediated autoimmune disease that targets hair follicles and interrupts hair regrowth. The microenvironment of the effector T cells and their related cytokines may affect immunopathogenesis around the hair bulb/bulge.

OBJECTIVE

To determine the contributory roles of the effector T cell subsets and related cytokines to the pathogenesis of AA.

METHODS

We investigated the correlation between histopathological grades and four clinical prognostic factors in 331 patients with AA, and analyzed the topography of T cell infiltrates and related cytokines around the hair bulb/bulge according to histopathological grades through immunohistochemical and double immunofluorescence studies on a subset of AA specimens.

RESULTS

First, the groups with more severe histopathological grades were associated with earlier onset, longer duration, more hair loss, as well as poorer therapeutic outcomes. Second, the pattern of CD4 and CD8 expression around the hair bulb/bulge varied by histopathological grade, with staining density decreasing in the following order: type 1>type 2>type 3. In addition, interferon-γ and transforming growth factor-β1 expression appeared denser in the peribulbar area. Interestingly, the denser CCR6⁺ cells (Th17 cells) showed more infiltration than CCR5⁺ cells (Th1 cells) around the hair bulb/bulge as histopathological grade worsened.

CONCLUSION

The insidious destruction of bulge stem cells and hair bulb matrix stem cells results in more severe hair loss in patients with chronic AA, which is mediated by Th17 lymphocyte and cytotoxic T lymphocyte infiltration. Furthermore, Th17 lymphocytes may play an even more important role than cytotoxic T cells in the development of AA.

Hair Follicle Generation by Injections of Adult Human Follicular Epithelial and Dermal Papilla Cells into Nude Mice

Objective

Dermal papilla and hair epithelial stem cells regulate hair formation and the growth cycle. Damage to or loss of these cells can cause hair loss. Although several studies claim to reconstitute hairs using rodent cells in an animal model, additional research is needed to develop a stable human hair follicle reconstitution protocol. In this study, we have evaluated hair induction by injecting adult cultured human dermal papilla cells and a mixture of hair epithelial and dermal papilla cells in a mouse model.

Materials and Methods

In this experimental study, discarded human scalp skins were used to obtain dermal papilla and hair epithelial cells. After separation, cells were cultured and assessed for their characteristics. We randomly allocated 15 C57BL/6 nude mice into three groups that received injections in their dorsal skin. The first group received cultured dermal papilla cells, the second group received a mixture of cultured epithelial and dermal papilla cells, and the third group (control) received a placebo [phosphate-buffered saline (PBS-)].

Results

Histopathologic examination of the injection sites showed evidence of hair growth in samples that received cells compared with the control group. However, the group that received epithelial and dermal papilla cells had visible evidence of hair growth. PKH tracing confirmed the presence of transplanted cells in the new hair.

Conclusion

Our data showed that injection of a combination of adult human cultured dermal papilla and epithelial cells could induce hair growth in nude mice. This study emphasized that the combination of human adult cultured dermal papilla and epithelial cells could induce new hair in nude mice.

Primary scalp alopecia: new histopathological tools, new concepts and a practical guide to diagnosis

The diagnosis of primary scalp alopecia remains one of the most challenging fields in dermatopathology. In this review, we would like to connect the established classification of primary alopecia into scarring (cicatricial) and non-scarring (non-cicatricial) with current concepts. We introduce a simplified pathway for the diagnosis of the most common causes of alopecia, including a discussion of tissue processing techniques and use of immunohistochemistry.

The Role of Symmetric Stem Cell Divisions in Tissue Homeostasis

Successful maintenance of cellular lineages critically depends on the fate decision dynamics of stem cells (SCs) upon division. There are three possible strategies with respect to SC fate decision symmetry: (a) asymmetric mode, when each and every SC division produces one SC and one non-SC progeny; (b) symmetric mode, when 50% of all divisions produce two SCs and another 50%-two non-SC progeny; (c) mixed mode, when both the asymmetric and two types of symmetric SC divisions co-exist and are partitioned so that long-term net balance of the lineage output stays constant. Theoretically, either of these strategies can achieve lineage homeostasis. However, it remains unclear which strategy(s) are more advantageous and under what specific circumstances, and what minimal control mechanisms are required to operate them. Here we used stochastic modeling to analyze and quantify the ability of different types of divisions to maintain long-term lineage homeostasis, in the context of different control networks. Using the example of a two-component lineage, consisting of SCs and one type of non-SC progeny, we show that its tight homeostatic control is not necessarily associated with purely asymmetric divisions. Through stochastic analysis and simulations we show that asymmetric divisions can either stabilize or destabilize the lineage system, depending on the underlying control network. We further apply our computational model to biological observations in the context of a two-component lineage of mouse epidermis, where autonomous lineage control has been proposed and notable regional differences, in terms of symmetric division ratio, have been noted-higher in thickened epidermis of the paw skin as compared to ear and tail skin. By using our model we propose a possible explanation for the regional differences in epidermal lineage control strategies. We demonstrate how symmetric divisions can work to stabilize paw epidermis lineage, which experiences high level of micro-injuries and a lack of hair follicles as a back-up source of SCs.

Hair regrowth through wound healing process after ablative fractional laser treatment in a murine model

BACKGROUND AND OBJECTIVE

Alopecia is one of the most common dermatological problems in the elderly; however, current therapies for it are limited by low efficacy and undesirable side effects. Although clinical reports on fractional laser treatment for various alopecia types are increasing, the exact mechanism remains to be clarified. The purposes of this study were to demonstrate the effect of ablative fractional laser treatment on hair follicle regrowth in vivo and investigate the molecular mechanism after laser treatment.

MATERIALS AND METHODS

Ablative CO2 fractional laser was applied to the shaved dorsal skin of 7-week-old C57BL/6 mice whose hair was in the telogen stage. After 12 mice were treated at various energy (10-40 mJ/spot) and density (100-400 spots/cm(2) ) settings to determine the proper dosage for maximal effect. Six mice were then treated at the decided dosage and skin specimens were sequentially obtained by excision biopsy from the dorsal aspect of each mouse. Tissue samples were used for the immunohistochemistry and reverse transcription polymerase chain reaction assays to examine hair follicle status and their related molecules.

RESULTS

The most effective dosage was the 10 mJ/spot and 300 spots/cm(2) setting. The anagen conversion of hair was observed in the histopathological examination, while Wnt/β-catenin expression was associated with hair regrowth in the immunohistochemistry and molecular studies.

CONCLUSIONS

Ablative fractional lasers appear to be effective for inducing hair regrowth via activation of the Wnt/β-catenin pathway in vivo. Our findings indicate that fractional laser treatment can potentially be developed as new treatment options for stimulating hair regrowth.

Hair-growth stimulation by conditioned medium from vitamin D3-activated preadipocytes in C57BL/6 mice

AIMS

Recently, immature adipocyte lineage cells have been suggested as a potential hair-growth stimulator. Diverse studies have been attempted to find methods for the preconditioning of immature adipocyte lineage cells. The present study investigates the effect of conditioned medium (CM) from vitamin D3 (Vd3) pre-activated preadipocytes on hair-growth ability.

MAIN METHODS

To test the effect of CM from Vd3 pre-activated preadipocytes on hair-growth efficiency in mice, we compared the differences in hair regenerated after injecting CM from mouse preadipocytes pre-activated with or without Vd3. Next, to determine the regulating factors, the VEGF level was measured by ELISA and angiogenesis level was evaluated by IHC. Finally, the signaling mechanism was investigated by inhibitor kinase assay and western blotting.

KEY FINDINGS

The CM from Vd3 pre-activated preadipocyte injection markedly promoted the ability of hair regeneration in mice. The VEGF levels were increased by Vd3 treatment in vitro and the CM from Vd3 pre-activated preadipocytes significantly increased the angiogenesis in vivo, suggesting the involvement of angiognensis in the hair regeneration induced by CM from pre-activated preadipocytes. In signaling study, Vd3-enhanced VEGF production was reduced by an ERK1/2 inhibitor and the level of ERK1/2 phosphorylation was increased by treatment with Vd3.

SIGNIFICANCE

This has been the first report on CM from Vd3 pre-activated preadipocyte displaying stimulatory effects on hair growth via the enhancement of angiogenesis in a hairless-induced C57BL/6 mice.

Expression of human skin-specific genes defined by transcriptomics and antibody-based profiling

To increase our understanding of skin, it is important to define the molecular constituents of the cell types and epidermal layers that signify normal skin. We have combined a genome-wide transcriptomics analysis, using deep sequencing of mRNA from skin biopsies, with immunohistochemistry-based protein profiling to characterize the landscape of gene and protein expression in normal human skin. The transcriptomics and protein expression data of skin were compared to 26 (RNA) and 44 (protein) other normal tissue types. All 20,050 putative protein-coding genes were classified into categories based on patterns of expression. We found that 417 genes showed elevated expression in skin, with 106 genes expressed at least five-fold higher than that in other tissues. The 106 genes categorized as skin enriched encoded for well-known proteins involved in epidermal differentiation and proteins with unknown functions and expression patterns in skin, including the C1orf68 protein, which showed the highest relative enrichment in skin. In conclusion, we have applied a genome-wide analysis to identify the human skin-specific proteome and map the precise localization of the corresponding proteins in different compartments of the skin, to facilitate further functional studies to explore the molecular repertoire of normal skin and to identify biomarkers related to various skin diseases.

The changes in the expression levels of follicular markers in keratoacanthoma depend on the stage: keratoacanthoma is a follicular neoplasm exhibiting infundibular/isthmic differentiation without expression of CK15

BACKGROUND

Although the precise etiology of keratoacanthoma (KA) is unknown, KA is generally assumed to differentiate toward hair follicles based on previous studies of experimental carcinogenesis.

METHODS

We performed a comprehensive immunohistochemical study of various follicular markers in all stages of KA. A total of 67 tumors, including 16 early or proliferative stage lesions, 43 well-developed stage lesions, five regressing stage lesions and three regressed stage lesions, were subjected to the analysis.

RESULTS

CK15 (clone C8/144B), CK19 and CD34 were not expressed at any stage. CK1, CK10, CK16, CK17, CK15 (clone LHK15) and calretinin showed dynamic changes in their expression in KA depending on the stage.

CONCLUSIONS

KA is a follicular neoplasm with infundibular/isthmic (upper segmental region of hair follicles) differentiation. It is considered that early or proliferative stage tumors show keratin-filled invaginations with infundibular differentiation and gradual isthmic differentiation. Well-developed examples of KA generally show isthmic differentiation in the whole lesions. The regressed stage KAs lose the features of this type of follicular differentiation and show epidermal characteristics. No expression of CK15 (clone C8/144B) was observed in KAs, although this finding is insufficient to completely rule out the correlation between the regression of KA and the hair follicle cycle.

Stem cell therapy in veterinary dermatology

BACKGROUND

Adult stem cells come from many sources and have the capacity to differentiate into many cell types, including those of the skin. The most commonly studied stem cells are those termed mesenchymal stem cells (MSCs), which are easily isolated from bone marrow and adipose tissue. Mesenchymal stem cells are known to produce a wide array of cytokines that modulate the regeneration process. The ease of collection, propagation and use of these MSCs in therapy of traumatic, ischaemic and immune-mediated skin conditions is emerging.

APPROACH AND EVIDENCE

In traumatic and ischaemic skin damage, MSCs are used in tissue-engineered skin and by direct injection into damaged tissue. For immune-mediated diseases, systemic administration of stem cells can modulate the immune system. The earliest clinical work has been with autologous stem cell sources, such as adipose tissue and bone marrow. In immune-mediated diseases, the MSCs are used to downregulate production of inflammatory cytokines and to block T-cell activation. Cells are generally given intravenously. Multiple sclerosis, rheumatoid arthritis and lupus have been successfully treated in human clinical trials. Mesenchymal stem cells can also stimulate resident local cells, such as keratinocytes and progenitor cells, to proliferate, migrate and repair skin injury and disease.

LOOKING AHEAD

The discovery of the MSC in adipose tissue has spawned a global effort to utilize these cells in therapy of a wide range of diseases of the skin. Reconstructive surgery, scar blocking and resolution and skin regeneration have all been shown to be possible in human and animal studies.