Recent Progress in Understanding the Effect of Sympathetic Nerves on Hair Follicle Growth

In this study, increased corticosterone from chronic stress prolonged hair follicle stem cell quiescence in mice, inhibiting regeneration, but restoring Gas6 expression overcame this inhibition.

This study found that sympathetic nerves and arrector pili muscles form a niche that modulates hair follicle stem cell activity, revealing their role in hair follicle regeneration.

This study explored the complex roles of niche cells in regulating hair follicle stem cells, identifying specific cell functions such as signaling, sensing, and relaying messages, which could provide insights into treating hair loss conditions like androgenetic alopecia and alopecia areata.

Stress can cause hair to turn gray by depleting stem cells.

This study found that micrografts containing human hair follicle mesenchymal stem cells significantly increased hair count and density compared to placebo over 58 weeks in patients experiencing hair loss.

This review discusses the advancements in intraoperative stem cell therapies and highlights their potential to improve hair regrowth, but it reports no new clinical results.

This study found that light stimulation of intrinsically photosensitive retinal ganglion cells in the eyes can activate hair follicle stem cells through a neural circuit involving the sympathetic nervous system.

This review highlights that microneedling shows some promise for improving hair growth in alopecia, particularly when used with other treatments, though more research is needed to establish its efficacy and protocols.

This review discusses the complex relationship between stress and various skin conditions, highlighting the role of the skin in the stress response and the brain-skin communication pathways, but reports no new research findings.

This study found that chemical sympathectomy inhibited hair follicle growth in mice, suggesting that sympathetic nerves may regulate keratinocyte behavior to promote hair growth.

This article explores the dynamic and energy-efficient nature of telogen hair follicles, challenging the notion of dormancy, and highlights their potential in advancing treatments for hair growth disorders.

This study suggests that chronic stress can lead to decreased skin pigmentation in mice by disrupting the skin's HPA axis, potentially making stress a risk factor for depigmentation.

This review examines the literature on the molecular and cellular makeup of the hair follicle niche and how it influences stem cell behavior during hair regeneration, but does not provide new experimental results.

This study found that autologous platelet-rich plasma increased hair growth potential by enhancing dermal papilla cell proliferation and stimulating key signaling pathways in both cell cultures and mice models.

COL17A1 is crucial for preventing hair graying and loss by supporting hair and pigment stem cells.

This review discusses the interplay between hormonal and immune systems in hair follicles and reports no new results, highlighting the need for further research on their role in skin biology and alopecia areata.

This review summarizes fundamental concepts and recent advancements in hair follicle biology, including insights from mouse models into broader molecular and cellular processes relevant to regeneration and development.

This review discusses the brain-skin connection, the skin's role in stress response, and highlights unmet challenges in understanding stress-induced skin inflammation but reports no new experimental findings.

This study found that human scalp hair follicles can respond to corticotropin releasing hormone stimulation similarly to the classical HPA axis, including up-regulating cortisol production and activating neuroendocrine feedback loops.

Stress can cause hair loss and skin issues by affecting hair growth cycles.

This study observed that hair follicle innervation in C57BL/6 mice occurs in sequential stages that closely correlate with the development of hair follicles, indicating an interdependent relationship between neuronal and epithelial morphogenesis.

This study found that substance P and calcitonin-gene-related peptide have different roles in regulating hair growth in mice, with substance P promoting anagen progression and calcitonin-gene-related peptide inhibiting it.

This article discusses the potential role of a local skin POMC system in the murine hair cycle and cutaneous stress responses, with no new results presented.

This article discusses the biologic and psychosocial significance of hair, the current limitations in hair growth drugs, and anticipates future therapies based on advancing hair follicle research.

This review discusses neural mechanisms involved in hair growth control, focusing on piloneural interactions, but reports no clinical findings; the authors suggest further exploration for managing hair growth disorders.

This study found that treating neonatal mice with the neurotoxin 6-OHDA resulted in temporary hair loss and thinner skin compared to control mice, linking sympathetic neurons to hair growth and skin thickness.