Stem cell activity-coupled suppression of endogenous retrovirus governs adult tissue regeneration.

Mammalian retrotransposons constitute 40% of the genome. During tissue regeneration, adult stem cells coordinately repress retrotransposons and activate lineage genes, but how this coordination is controlled is poorly understood. Here, we observed that dynamic expression of histone methyltransferase SETDB1 (a retrotransposon repressor) closely mirrors stem cell activities in murine skin. SETDB1 ablation leads to the reactivation of endogenous retroviruses (ERVs, a type of retrotransposon) and the assembly of viral-like particles, resulting in hair loss and stem cell exhaustion that is reversible by antiviral drugs. Mechanistically, at least two molecularly and spatially distinct pathways are responsible: antiviral defense mediated by hair follicle stem cells and progenitors and antiviral-independent response due to replication stress in transient amplifying cells. ERV reactivation is promoted by DNA demethylase ten-eleven translocation (TET)-mediated hydroxymethylation and recapitulated by ablating cell fate transcription factors. Together, we demonstrated ERV silencing is coupled with stem cell activity and essential for adult hair regeneration.

Epidermal ET-1 signal induces activation of resting hair follicles by upregulating the PI3K/AKT pathway in the dermis.

The prevalence of alopecia has increased recently. Hair loss is often accompanied by the resting phase of hair follicles (HFs). Dermal papilla (DP) plays a crucial role in HF development, growth, and regeneration. Activating DP can revive resting HFs. Augmenting WNT/ß-catenin signaling stimulates HF growth. However, the factors responsible for activating resting HFs effectively are unclear. In this study, we investigated epidermal cytokines that can activate resting HFs effectively. We overexpressed ß-catenin in both in vivo and in vitro models to observe its effects on resting HFs. Then, we screened potential epidermal cytokines from GEO DATASETs and assessed their functions using mice models and skin-derived precursors (SKPs). Finally, we explored the molecular mechanism underlying the action of the identified cytokine. The results showed that activation of WNT/ß-catenin in the epidermis prompted telogen-anagen transition. Keratinocytes infected with Ctnnb1-overexpressing lentivirus enhanced SKP expansion. Subsequently, we identified endothelin 1 (ET-1) expressed higher in hair-growing epidermis and induced the proliferation of DP cells and activates telogen-phase HFs in vivo. Moreover, ET-1 promotes the proliferation and stemness of SKPs. Western blot analysis and in vivo experiments revealed that ET-1 induces the transition from telogen-to-anagen phase by upregulating the PI3K/AKT pathway. These findings highlight the potential of ET-1 as a promising cytokine for HF activation and the treatment of hair loss.

Lineage-specific requirements of Alx4 function in craniofacial and hair development.

BACKGROUND: Disruption of ALX4 causes autosomal dominant parietal foramina and autosomal recessive frontonasal dysplasia with alopecia, but the mechanisms involving ALX4 in craniofacial and other developmental processes are not well understood. Although mice carrying distinct mutations in Alx4 have been previously reported, the perinatal lethality of homozygous mutants together with dynamic patterns of Alx4 expression in multiple tissues have hindered systematic elucidation of the cellular and molecular mechanisms involving Alx4 in organogenesis and disease pathogenesis. RESULTS: We report generation of Alx4f/f conditional mice and show that tissue-specific Cre-mediated inactivation of Alx4 in cranial neural crest and limb bud mesenchyme, respectively, recapitulated craniofacial and limb developmental defects as found in Alx4-null mice but without affecting postnatal survival. While Alx4-null mice that survive postnatally exhibited dorsal alopecia, mice lacking Alx4 function in the neural crest lineage exhibited a highly restricted region of hair loss over the anterior skull whereas mice lacking Alx4 in the cranial mesoderm lineage exhibited normal hair development, suggesting that Alx4 plays partly redundant roles in multiple cell lineages during hair follicle development. CONCLUSION: The Alx4f/f mice provide a valuable resource for systematic investigation of cell type- and stage-specific function of ALX family transcription factors in development and disease.

M1 polarization of macrophages promotes stress-induced hair loss via interleukin-18 and interleukin-1ß.

Stress-induced hair loss is a prevalent health concern, with mechanisms that remain unclear, and effective treatment options are not yet available. In this study, we investigated whether stress-induced hair loss was related to an imbalanced immune microenvironment. Screening the skin-infiltrated immune cells in a stressed mouse model, we discovered a significant increase in macrophages upon stress induction. Clearance of macrophages rescues mice from stress-induced hair shedding and depletion of hair follicle stem cells (HFSCs) in the skin, demonstrating the role of macrophages in triggering hair loss in response to stress. Further flow cytometry analysis revealed a significant increase in M1 phenotype macrophages in mice under stressed conditions. In searching for humoral factors mediating stress-induced macrophage polarization, we found that the hormone Norepinephrine (NE) was elevated in the blood of stressed mice. In addition, in-vivo and in-vitro studies confirm that NE can induce macrophage polarization toward M1 through the ß-adrenergic receptor, Adrb2. Transcriptome, enzyme-linked immunosorbent assay (ELISA), and western blot analyses reveal that the NLRP3/caspase-1 inflammasome signaling and its downstream effector interleukin 18 (IL-18) and interleukin 1 beta (IL-1ß) were significantly upregulated in the NE-treated macrophages. However, inhibition of the NE receptor Adrb2 with ICI118551 reversed the upregulation of NLRP3/caspase-1, IL-18, and IL-1ß. Indeed, IL-18 and IL-1ß treatments lead to apoptosis of HFSCs. More importantly, blocking IL-18 and IL-1ß signals reversed HFSCs depletion in skin organoid models and attenuated stress-induced hair shedding in mice. Taken together, this study demonstrates the role of the neural (stress)-endocrine (NE)-immune (M1 macrophages) axis in stress-induced hair shedding and suggestes that IL-18 or IL-1ß may be promising therapeutic targets.

Results of the Dutch scalp cooling registry in 7424 patients: analysis of determinants for scalp cooling efficacy.

BACKGROUND: Chemotherapy-induced alopecia is a common consequence of cancer treatment with a high psychological impact on patients and can be prevented by scalp cooling (SC). With this multi-center patient series, we examined the results for multiple currently used chemotherapy regimens to offer an audit into the real-world determinants of SC efficacy. MATERIALS AND METHODS: The Dutch Scalp Cooling Registry collected data on 7424 scalp-cooled patients in 68 Dutch hospitals. Nurses and patients completed questionnaires on patient characteristics, chemotherapy, and SC protocol. Patient-reported primary outcomes at the start of the final SC session included head cover (HC) (eg, wig/scarf) use (yes/no) as a surrogate for patient satisfaction with SC and WHO score for alopecia (0 = no hair loss up to 3 = total alopecia) as a measure of scalp cooling success. Exhaustive logistic regression analysis stratified by chemotherapy regimen was implemented to examine characteristics and interactions associated with the SC result. RESULTS: Overall, over half of patients (n = 4191, 56%) did not wear a HC and 53% (n = 3784/7183) reported minimal hair loss (WHO score 0/1) at the start of their final treatment. Outcomes were drug and dose dependent. Besides the chemotherapy regimen, this study did not identify any patient characteristic or lifestyle factor as a generic determinant influencing SC success. For non-gender specific cancers, gender played no statistically significant role in HC use nor WHO score. CONCLUSIONS: Scalp cooling is effective for the majority of patients. The robust model for evaluating the drug and dose-specific determinants of SC efficacy revealed no indications for changes in daily practice, suggesting factors currently being overlooked. As no correlation was identified between the determinants explaining HC use and WHO score outcomes, new methods for evaluation are warranted.

Psychological stress induces hair regenerative disorders through corticotropin-releasing hormone-mediated autophagy inhibition.

Psychosocial stress is increasing, causing a growing number of people to suffer from hair loss. Stress-related corticotropin-releasing hormone (CRH) is associated with hair loss, but the mechanism by which hair follicles respond to stress and CRH remain poorly understood. The aim of the study is to elucidate the association between CRH and stress-related hair regenerative disorders, and reveal the potential pathological mechanisms. A chronic unpredictable stress mouse model and a chronic social defeat stress mouse model were used to examine the role of CRH and stress-related hair regrowth. Chronic unpredictable stress and chronic social defeat stress increased the expression of CRH and CRH receptors (CRHRs), and contributed to the onset of hair-cycle abnormalities. Psychoemotional stress and stress-related CRH blocked hair follicle regrowth, which could be restored by astressin, a CRHR antagonist. Long-term exposure to either chronic unpredictable stress or CRH induced a decrease in autophagy, which could be partially rescued by astressin. Activating CRHR, by stress or CRH administration, decreased autophagy via the mTOR-ULK1 signaling pathway to mediate hair regenerative disorders, which could be partially reversed through enhancing autophagy by administration of brefeldin A. These findings indicate that CRH-mediated autophagy inhibition play an important role in stress-induced hair regenerative disorders. CRH regulates the local hypothalamic-pituitary-adrenal axis of hair follicles, but also plays an independent pathogenic role in stress-related hair regenerative disorders through CRH-mediated autophagy inhibition. This work contributes to the present understanding of hair loss and suggests that enhancing autophagy may have a therapeutic effect on stress-induced hair loss.

Advances in the Application of Microneedles in the Treatment of Local Organ Diseases.

In recent years, microneedles (MNs) have attracted a lot of attention due to their microscale sizes and high surface area (500-1000 µm in length), allowing pain-free and efficient drug delivery through the skin. In addition to the great success of MNs based transdermal drug delivery, especially for skin diseases, increasing studies have indicated the expansion of MNs to diverse nontransdermal applications, including the delivery of therapeutics for hair loss, ocular diseases, and oral mucosal. Here, the current treatment of hair loss, eye diseases, and oral disease is discussed and an overview of recent advances in the application of MNs is provided for these three noncutaneous localized organ diseases. Particular emphasis is laid on the future trend of MNs technology development and future challenges of expanding the generalizability of MNs.

Dosimetric comparison of advanced radiation techniques for scalp-sparing in low-grade gliomas.

BACKGROUND: Alopecia causes significant distress for patients and negatively impacts quality of life for low-grade glioma (LGG) patients. We aimed to compare and evaluate variations in dose distribution for scalp-sparing in LGG patients with proton therapy and photon therapy, namely intensity-modulated proton therapy (IMPT), intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT). METHODS: This retrospective study utilized a dataset comprising imaging data from 22 patients with LGG who underwent postoperative radiotherapy. Treatment plans were generated for each patient with scalp-optimized (SO) approaches and scalp-non-optimized (SNO) approaches using proton techniques and photons techniques; all plans adhered to the same dose constraint of delivering a total radiation dose of 54.04 Gy to the target volume. All treatment plans were subsequently analyzed. RESULTS: All the plans generated in this study met the dose constraints for the target volume and OARs. The SO plans resulted in reduced maximum scalp dose (Dmax), mean scalp dose (Dmean), and volume of the scalp receiving 30 Gy (V30) and 40 Gy (V40) compared with SNO plans in all radiation techniques. Among all radiation techniques, the IMPT plans exhibited superior performance compared to other plans for dose homogeneity as for SO plans. Also, IMPT showed lower values for Dmean and Dmax than all photon radiation techniques. CONCLUSION: Our study provides evidence that the SO approach is a feasible technique for reducing scalp radiation dose. However, it is imperative to conduct prospective trials to assess the benefits associated with this approach.

Irisin promotes hair growth and hair cycle transition by activating the GSK-3ß/ß-catenin pathway.

Hair loss affects men and women of all ages. Myokines, which are mainly secreted by skeletal muscles during exercise, have numerous health benefits. VEGF, IGF-1, FGF and irisin are reprehensive myokines. Although VEGF, IGF-1 and FGF are positively associated with hair growth, few studies have researched the effects of irisin on hair growth. Here, we investigated whether irisin promotes hair growth using in vitro, ex vivo and in vivo patch assays, as well as mouse models. We show that irisin increases proliferation, alkaline phosphatase (ALP) activity and mitochondrial membrane potential in human dermal papilla cells (hDPCs). Irisin activated the Wnt/ß-catenin signalling pathway, thereby upregulating Wnt5a, Wnt10b and LEF-1, which play an important role in hair growth. Moreover, irisin enhanced human hair shaft elongation. In vivo, patch assays revealed that irisin promotes the generation of new hair follicles, accelerates entry into the anagen phase, and significantly increases hair growth in C57BL/6 mice. However, XAV939, a Wnt/ß-catenin signalling inhibitor, suppressed the irisin-mediated increase in hair shaft and hair growth. These results indicate that irisin increases hair growth via the Wnt/ß-catenin pathway and highlight its therapeutic potential in hair loss treatment.

AP collagen peptides (APCPs) promote hair growth by activating the GSK-3ß/ß-catenin pathway and improve hair condition.

AP collagen peptides (APCPs) are enzymatically decomposed collagen peptides that contain tri-peptides such as glycine-proline-hydroxyproline. We found that APCPs increased the proliferation of both human dermal papilla cells (hDPCs) and human outer root sheath cells (hORSCs). APCPs also stimulated the secretion of several growth factors, including IGFBP-6, PDGF-AB, PIGF and VEGF in hDPCs. Moreover, APCPs enhanced the phosphorylation of Akt(Ser473), GSK-3ß(Ser9) and ß-catenin(Ser675), indicating the activation of the GSK-3ß/ß-catenin signalling pathway. Ex vivo culture of human hair follicles (hHFs) tissue and in vivo patch assay revealed that APCPs promoted the elongation of hHFs and the induction of new hair shafts. In a mouse model, APCPs significantly promoted the transition from telogen to anagen phase and prolonged anagen phase, resulting in increased hair growth. APCPs also improved the thickness, amino acid content (cystine and methionine) and roughness of mouse hair. Taken together, these findings demonstrate that APCPs accelerate hair growth and contribute to overall hair health. Therefore, APCPs have the potential to be utilized as a food supplement and ingredient for preventing hair loss and maintaining hair health.

Treatment for central centrifugal cicatricial alopecia-Delphi consensus recommendations.

BACKGROUND: There is no established standard of care for treating central centrifugal cicatricial alopecia (CCCA), and treatment approaches vary widely. OBJECTIVE: To develop consensus statements regarding the use of various pharmacological therapies in treating adults with CCCA. METHODS: We invited 27 dermatologists with expertise in hair and scalp disorders to participate in a 3-round modified Delphi study between January and March 2023. Statements met strong consensus if 75% of respondents agreed or disagreed. Statements met moderate consensus if 55% or more but less than 75% agreed or disagreed. RESULTS: In round 1, 5 of 33 (15.2%) statements met strong consensus, followed by 9 of 28 (32.1%) in round 2. After the final round 3 meeting, strong consensus was reached for 20 of 70 (28.6%) overall statements. Two statements achieved moderate consensus. LIMITATIONS: This study included only English-speaking, US-based dermatologists and did not consider nonpharmacological therapies. CONCLUSION: Despite varying opinions among dermatologists, consensus was reached for several statements to help clinicians manage CCCA. We also highlight areas that lack expert consensus with the goal of advancing research and therapeutic options for CCCA.

Outcomes of Down-Titration in Patients with Severe Scalp Alopecia Areata Initially Treated with Baricitinib 4-mg: Week 152 data from BRAVE-AA2.

BACKGROUND: Baricitinib, an oral selective Janus kinase inhibitor, is approved to treat adults with severe alopecia areata (AA). OBJECTIVE: To report the Week 152 efficacy results from the Phase 3 trial BRAVE-AA2 down-titration sub-study. METHODS: BRAVE-AA2 enrolled 546 adults with severe AA (Severity of Alopecia Tool [SALT] score ≥50). Baricitinib 4-mg treated patients achieving a clinical response (SALT score ≤20) at Week 52 were rerandomized 1:1 to stay on 4-mg or down-titrate to 2-mg. Last observation carried forward was used to impute missing or censored data. RESULTS: At Week 52, 86/234 (36.8%) baricitinib 4-mg treated patients were eligible for down-titration; 44 remained on 4-mg while 42 down-titrated to 2-mg. At Week 152, 39/44 (88.6%) 4-mg treated patients had maintained clinical response, compared to 24/41 (58.5%) down-titrated patients. Among down-titrated patients, loss of treatment benefit was less frequent in those with sustained response and SALT score ≤5 at Week 52. LIMITATIONS: Method and timing of down-titration were pre-specified in the protocol based on Week 52 responder status and not on other clinical factors. CONCLUSION: More than half of down-titrated patients maintained response. Sustained treatment response and/or near-total regrowth may be associated with a greater likelihood of response maintenance after down-titration.

Lessons from a scoping review: Clinical presentations of central centrifugal cicatricial alopecia.

BACKGROUND: Central centrifugal cicatricial alopecia (CCCA) nomenclature describes a typical clinical presentation of cicatricial hair loss that begins on the vertex scalp with progressive, symmetric, and centrifugal evolution. However, atypical presentations have been noted clinically by the authors and reported in the literature. OBJECTIVE: We sought to characterize the distribution of hair loss in published cases of adult patients with CCCA. METHODS: A 3-step search process was used to evaluate research articles in Cumulative Index to Nursing & Allied Health, EMBASE, Google Scholar, MEDLINE, Scopus, and Web of Science databases. Studies with scalp photography or description of hair loss distribution were included. Three researchers evaluated eligible studies for clinical subtypes. Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Review was used to report results. RESULTS: Ninety-nine studies consisting of 281 cases of CCCA were included. Hair loss distributions included variants of the classic presentation along with distinct subtypes such as patchy, occipital, parietal, frontal, temporal, and trichorrhexis. LIMITATIONS: Studies had significant homogeneity, as the classic distribution of CCCA was commonly reported. Additionally, clinically diagnosed cases may have concurrent diagnoses, and numerous studies did not report trichoscopy findings. CONCLUSION: CCCA terminology may not always be reflective of clinical presentation. Understanding atypical presentations is essential to inform appropriate and targeted treatment.

Risk of Suicide, Hair Loss, and Aspiration with GLP1-Receptor Agonists and Other Diabetic Agents: A Real-World Pharmacovigilance Study.

PURPOSE: With the increasing popularity of glucagon-like peptide 1 receptor agonists (GLP1-RAs), numerous safety concerns arose pertaining to suicide, hair loss, and aspiration risks. We attempted to validate these concerns. METHODS: We queried four pharmacovigilance databases to compare GLP1-RAs to sodium-glucose transporter 2 inhibitors (SGLT2is) with respect to these adverse events (AE): the FDA Adverse Event Reporting System (FAERS), the Australian Database of Adverse Event Notifications (DAEN), the European Medicines Agency's (EudraVigilance), and the World Health Organization-Vigibase. OpenVigil 2.1 was utilized to perform a disproportionality analysis for GLP1-RAs, SGLT2is, dipeptidyl peptidase 4 inhibitors (DPP4is), sulfonylureas, metformin, and insulin. The following indices were extracted from the FAERS database from Q4/2003 until Q3/2023: relative reporting ratio (RRR), proportional reporting ratio (PRR), reporting odds ratio (ROR), and chi-squared (χ2). A positive signal was detected if PRR > 2 and χ2 > 4 for any drug-event pair. RESULTS: No positive signals were observed between GLP1-RAs and either suicide, hair loss, or aspiration risks. Semaglutide [ROR = 0.60 (0.51-0.71)] and liraglutide [ROR = 0.28 (0.23-0.35)] had higher suicidal events than DPP4is and SGLT2is. GLP1-RAs were the most reported class with hair loss [ROR = 0.61 (0.60-0.64)], and semaglutide, liraglutide, and dulaglutide were the three leading medications. GLP1-RAs ranked lower with aspiration events, which were led by sitagliptin and DPP4is as a group. CONCLUSION: GLP1-RAs exhibit higher reporting of suicide, hair loss, and aspiration events when compared to several other antidiabetic medications despite not meeting the criteria for positive signals yet. This warrants intensive monitoring and reporting.

Compound Follicles in Folliculitis Decalvans Do Not Contain Vellus and Retained Telogen Follicles-A Pilot Histopathologic Series on Polytrichia.

BACKGROUND: Polytrichia is a common clinical and trichoscopic feature in folliculitis decalvans (FD) that morphologically corresponds to compound follicular structures (CFS) of six or more follicles sharing a single infundibulum, surrounded by fibrosis. OBJECTIVES: To characterize the type of follicles in the CFS in scalp biopsy specimens from FD. METHODS: We retrospectively reviewed 10 scalp biopsy specimens obtained by using the trichoscopy-guided approach from the affected scalp of patients diagnosed with early-stage FD between 2018 and 2023. We assessed the number and type of follicles within the CFS on horizontal sections. RESULTS: The total number of assessed follicles was 205, out of which 159 were part of CFS. Of those, 156 were terminal follicles (146 anagen and ten telogen), three intermediate, and zero vellus follicles. Other common findings included dense mixed cell infiltrate consisting of histiocytes, plasma cells, lymphocytes, neutrophils, and eosinophils; psoriasiform hyperplasia; and fragmented hair shafts. CONCLUSIONS: We show that CFS in FD are composed largely of terminal anagen follicles. This may help with further understanding of the disease.

Characterization of the role of Facebook groups for patients who use scalp cooling therapy: a survey study.

Since the emergence of scalp cooling therapy (SCT) for the prevention of chemotherapy-induced alopecia (CIA), support groups on social media platforms for interested patients have surfaced. Though there are over 20,000 active members across SCT Facebook groups, little is known about how members use this platform. A 23-question survey was posted in five scalp cooling Facebook groups, reaching 219 women. Results indicated that these Facebook groups play clear roles in providing the following: (1) a supportive community for patients, (2) instructions for SCT use, (3) advice regarding insurance coverage and reimbursement, and (4) recommendations for over-the-counter products for hair loss. Despite reported interest in hair loss products, only 5% of patients sought medical treatment from dermatologists. Due to group-specific access restrictions, private Facebook groups provide patients with a protected platform to learn more about SCT from both those with personal experience and SCT company specialists. Providers may consider recommending these online groups to interested patients during the scalp cooling counseling process. As patients with CIA express a growing interest in over-the-counter hair, eyebrow, and eyelash products, it is important for dermatologists to be aware of where their patients obtain recommendations, and further, if these recommendations have clinical evidence of efficacy.

Validation and responsiveness of the English version of the Chemotherapy-Induced Alopecia Distress Scale (CADS) in breast cancer patients.

PURPOSE: This study aimed to validate the Chemotherapy-Induced Alopecia Distress Scale (CADS) in a diverse English-speaking population and patients with endocrine treatment-induced alopecia (EIA). OBJECTIVE: Chemotherapy and endocrine therapy commonly cause alopecia in breast cancer patients, leading to significant psychological and social challenges. The CADS was developed to assess the psychosocial impact of alopecia, but its generalizability beyond Korean patients requires further investigation. METHODS: Data from the CHANCE study (NCT02530177), which focused on non-metastatic breast cancer, was used. The cohort included 256 patients, and CADS data were collected at baseline, 6 months after chemotherapy completion, or 12 months after initiating endocrine therapy. The CADS questionnaire comprised 17 items covering physical and emotional health, daily activities, and relationships. Reliability was assessed using Cronbach's alpha, and responsiveness was measured by effect size. RESULTS: The CADS exhibited good reliability, with Cronbach's alpha of 0.91 for the overall score, indicating acceptable internal consistency in both chemotherapy (0.89) and endocrine therapy (0.86) groups. Longitudinal responsiveness was supported by an effect size of 0.49 between decreasing satisfaction with hair growth and increasing emotional distress. Cross-sectional validity was confirmed, with effect sizes of 0.91 and 0.92 for satisfaction with hair growth and emotional and activity domains, respectively. CONCLUSION: The CADS is a valid and responsive tool for assessing the psychosocial impact of chemotherapy-induced alopecia and endocrine treatment-induced alopecia in a diverse Western patient population.

Status of research on the development and regeneration of hair follicles.

Hair loss, or alopecia, is a prevalent condition in modern society that imposes substantial mental and psychological burden on individuals. The types of hair loss, include androgenetic alopecia, alopecia areata, and telogen effluvium; of them, androgenetic alopecia is the most common condition. Traditional treatment modalities mainly involve medical options, such as minoxidil, finasteride and surgical interventions, such as hair transplantation. However, these treatments still have many limitations. Therefore, exploring the pathogenesis of hair loss, specifically focusing on the development and regeneration of hair follicles (HFs), and developing new strategies for promoting hair regrowth are essential. Some emerging therapies for hair loss have gained prominence; these therapies include low-level laser therapy, micro needling, fractional radio frequency, platelet-rich plasma, and stem cell therapy. The aforementioned therapeutic strategies appear promising for hair loss management. In this review, we investigated the mechanisms underlying HF development and regeneration. For this, we studied the structure, development, cycle, and cellular function of HFs. In addition, we analyzed the symptoms, types, and causes of hair loss as well as its current conventional treatments. Our study provides an overview of the most effective regenerative medicine-based therapies for hair loss.

Evaluation of the effects of adding an adipose tissue-derived stromal vascular fraction to platelet-rich plasma injection in the treatment of androgenetic alopecia: A randomized clinical trial.

BACKGROUND: Stromal vascular fraction (SVF) cells derived from adipose tissue and platelet-rich plasma (PRP) are among novel treatments for androgenetic alopecia (AGA). We aimed to investigate the effect of adding SVF to PRP and compare it to administering PRP injection alone. METHODS: Eighteen patients were randomly divided into two groups of nine. The PRP group was treated with PRP at all three visits at 1-month intervals, while the SVF-PRP group received an SVF injection on the first visit and a PRP injection on the second and third visits. Each group was evaluated at baseline and 20 weeks after the therapy's initiation. RESULTS: Changes in mean hair diameter and hair count compared to baseline were significant in both groups. The PRP group experienced a greater increase in mean hair count than the SVF-PRP group, and the SVF-PRP group had a marginally greater increase in hair diameter than the PRP group. These differences were not statistically significant compared to each other. The patient and physician assessment scores exceeded the mean (on a scale from 0: poor to 3: excellent) in both groups. CONCLUSION: Adding one SVF injection to two PRP treatment sessions versus three PRP injections alone had no significant difference in evaluated variables. If additional research demonstrates the same results, we suggest that multiple SVF injection sessions may be required to produce a statistically significant difference compared to PRP injection alone. Moreover, considering lower cost and greater accessibility of PRP, it can be used before SVF in the treatment of AGA.

Shock Waves for Hair Growth and Regeneration in Patients With Female Pattern Hair Loss.

BACKGROUND: Female pattern hair loss (FPHL) is women's most common form of alopecia. The study aimed to evaluate the efficacy of extracorporeal shock waves for hair growth and regeneration in women with FPHL. METHODS: A prospective single-center noncontrolled study was conducted in patients with FPHL who underwent eight treatment sessions with C-Actor, a shock wave applicator. Outcome measures included total hair count, number of follicular units (FUs)-single FUs, double FUs, triple and bigger FUs-the average thickness, cumulative hair thickness, and changes in the Derived Sinclair scale, assessed with Tricholab (Fotofinder System). Patients completed a survey to assess their subjective perceptions of hair improvement regarding softness, hair loss, quality, and volume. RESULTS: Twenty women were included with a mean age of 43 (SD = 5.65). The mean increase in total hair count was 8.9% (p < 0.00001), in number of FUs 4.6% (p = 0.00031), in number of triple and bigger FUs 18.4% (p = 0.0004), in cumulative hair thickness 8.0% (p < 0.00001), with a decrease of 5.7% in mean Derived Sinclair scale value by 2.2-2.1 (p < 0.0001). After 3 months, 85% of patients perceived improvement in hair volume. CONCLUSION: Extracorporeal shock waves for hair growth and capillary regeneration in women with FPHL showed statistically significant outcomes, and all patients reported an improvement in hair characteristics.