The Hair Follicle: An Underutilized Source of Cells and Materials for Regenerative Medicine

This study found that human hair follicle dermal cells, specifically dermal sheath cells, can serve as an alternative and potentially superior cell source for constructing the dermal component of bioengineered skin in both in vitro and in vivo settings.

In this study, using stirred-suspension bioreactors to expand dermal stem cells resulted in larger numbers, but had reduced efficiency in forming hair follicle structures compared to static culture conditions.

This study revealed that in androgenic alopecia, the proximal attachment of the arrector pili muscle to the hair follicle is often lost or significantly reduced.

This study found that macrophages treated with keratin in vitro were more similar to anti-inflammatory M2 macrophages and reduced astrocyte reactivity, potentially limiting secondary inflammatory damage after spinal cord injury.

This study suggests that the postnatal loss of hair follicle formation in wounds may be due to elevated Wnt/β-catenin activation in the dermis, affecting fibroblast function in mice.

This study describes a method to create keratin hydrogels with adjustable erosion rates by mixing different ratios of keratose and kerateine, enabling controlled release of therapeutic agents like insulin-like growth factor 1.

This study found that keratin hydrogels extracted from human hair showed potential as biodegradable and biocompatible filler materials, promoting angiogenesis and cell proliferation in rat models.

This study found that alkylation of kerateine cysteine residues created a cell-compatible method for controlling hydrogel erosion rates and therapeutic agent release in keratin-based systems.

This study found that human mesenchymal stromal cells derived from hair follicle dermal sheath showed promising growth and wound-healing properties in vitro and in diabetic mice, suggesting potential for therapeutic use.

Keratin-based hydrogels from human hair improve wound healing effectively.

This study found that super-enhancers are essential for hair follicle stem cell identity, lineage commitment, and plasticity in mice, with SOX9 being a key regulator of these chromatin dynamics.

This study found that keratin coatings from human hair may improve the colony-forming efficiency of human mesenchymal stem cells by moderating donor variability, suggesting a potential use in clinical applications.

This study found that macrophages near hair follicles contribute to the activation of skin epithelial stem cells in mice, suggesting a novel role for macrophages in regulating hair growth.

This review explores the relationship between hair follicles and wound healing, emphasizing the importance of translating scientific findings into practical therapies for chronic wounds, but it reports no new experimental results.

This review discusses various stem cell compartments in adult murine and human epidermis, examining their expressed markers and characterization assays, and reports no new experimental results.

This study identified mutations in the FGF5 gene as a cause of extreme eyelash growth in Pakistani families, highlighting a potential target for regulating eyelash growth.

This study found that in mice, epidermal Wnt/β-catenin signaling influences adipocyte differentiation and hair growth, suggesting its critical role in synchronizing adipogenesis with the hair growth cycle.

This study found that in androgenic alopecia, the arrector pili muscle degenerates and is replaced by fat, unlike in normal skin or telogen effluvium.

This review summarizes the anatomy and physiology of the arrector pili muscle and discusses its potential role in hair loss disorders, reporting no new clinical results.

This study found that skin fibroblasts in mice arise from two distinct lineages which contribute differently to dermal structure and repair, impacting hair follicle formation during wound healing.

This study found that the creation of hair follicle lumens in mice is driven by the outward migration of keratin 79-positive cells, suggesting a novel mechanism for generating hollow cores in hair follicles.

This study found that altering cell culture conditions to form three-dimensional papilla spheroids can restore the ability of human dermal papilla cells to induce hair growth in adult skin.

This study found that using a keratin hydrogel scaffold as a filler in collagen nerve conduits significantly improved nerve regeneration and motor recovery in Macaca fascicularis monkeys compared to saline.

Different types of stem cells and their environments are key to skin repair and maintenance.

This study found that fibroblast growth factor 9, initially secreted by γδ T cells, plays a key role in modulating hair follicle regeneration in mice after skin wounds.

In this study, the researchers found that a keratin hydrogel filler in nerve conduits led to earlier Schwann cell migration and improved cellular behaviors compared to other fillers in a rat sciatic nerve model.

This study characterized keratin-based biomaterials that self-assemble into hydrogels, demonstrating their potential to achieve hemostasis in a lethal liver injury model through specific biomaterial-receptor interactions.

This review discusses the biology of hair follicle stem cells and highlights their potential for applications in regenerative medicine, drug, and gene delivery, but reports no new clinical results.

This study reports that hair regeneration in live mice involves spatially regulated stem cell divisions and requires mesenchymal interactions, observed in real-time using a novel non-invasive imaging method.

This study found that dermal papilla cells from human hair follicles can be reprogrammed into induced pluripotent stem cells, but their efficiency is similar to that of fibroblasts, unlike in mice.

This study found that intradermal adipocyte lineage cells in mice are necessary and sufficient to activate follicular stem cells, highlighting their role in regulating skin stem cell activity.

This study observed that keratose, derived from human hair, integrated well in mouse tissue and remodeled with collagen, suggesting potential as a non-toxic biomaterial for regenerative applications.

This study observed that hepatocyte adhesion to human hair keratin biomaterials was mediated by the hepatic ASGPR, as blocking this receptor reduced cell attachment.

This study observed that keratose hydrogels sustained ciprofloxacin release over three weeks and inhibited Staphylococcus aureus growth in vitro for 23 days and in mice for 2 weeks.

This study found that keratin films made from human hair can potentially substitute for human nail plates in drug permeability studies, but they show higher sensitivity to penetration enhancers compared to bovine hooves.

Nephronectin helps attach muscle cells to hair follicles.

This study suggests that Lrig1-positive cells form a previously unknown reservoir of interfollicular epidermal stem cells in adult mouse skin, influencing epidermal proliferation and hair follicle development.

This review discusses the shedding phase of the hair cycle, known as exogen, and reports no new findings while analyzing related processes like club fiber formation and release.

This review discusses the reuse of molecular mechanisms involved in embryonic skin development for maintaining adult epidermal homeostasis and reports no new results.

This study found that intra-follicular Wnt signaling and dermal BMP signaling oscillate differently during hair cycling in mice, affecting hair wave propagation and phases of hair growth.

This review summarizes the cell type distribution and functional significance of human keratins, emphasizing their roles in tumor diagnosis and potential clinical applications, and reports no new clinical findings.

This study found that scaffolds made from human hair proteins supported better cell growth and interactions than control surfaces, indicating potential use in tissue engineering.

This review examines regenerative hair waves and complex hair cycle domains in transgenic mice, highlighting how these dynamic processes contribute to skin regeneration and the physiological regulation of organs, but reports no new experimental results.

This study found that a biomaterial gel made from human hair keratins facilitated nerve regeneration in an animal model, potentially matching the effectiveness of traditional autografts.

Human hair follicle cells can become fat and bone cells, useful for therapy.

This study demonstrated that clonal dermal papilla and dermal sheath cell lines from hair follicles can differentiate into lipid and bone cells, suggesting their potential as a stem cell source for tissue engineering.

This article reviews the structure and chemistry of hair across ethnicities and how these factors affect hair properties and treatment responses, but reports no new research findings.

This study found that cathepsin L deficiency in mice led to significant abnormalities in hair follicle development and cycling, including disrupted hair shaft outgrowth and premature hair growth phase entry.

This study developed a rapid method to extract proteins from human hair, revealing phosphorylation on serine and threonine residues in alpha-keratins and matrix proteins.

This study demonstrated that intact adult human dermal papillae can induce hair growth when implanted into mouse hair follicles, highlighting their potential for advancing hair follicle biology and therapeutic approaches.

This study found that the volume of a hair follicle's dermal papilla is strongly correlated with its size, primarily due to the number of cells it contains and the volume of extracellular matrix.

This study found that dermal papilla cells in human hair follicles exhibit stronger expression of VEGF mRNA and protein compared to other follicular cells, suggesting their key role in angiogenic processes related to hair growth.

Using patient's own hair cells can effectively heal chronic leg ulcers.

This study found that men with common male pattern baldness received less favorable initial social perceptions, including lower ratings of physical attractiveness, than their nonbalding counterparts.