Novel complex of cosmetic ingredients with promising action in preventing hair loss and follicular aging through mechanism involving enrichment of WNT/signaling, mitochondrial activity, and stem cells maintenance

Gas-propelled anti-hair follicle aging microneedle patch for the treatment of androgenetic alopecia

Existing treatments for androgenetic alopecia (AGA) are unsatisfactory, owing to the two major reasons: (1) Oxidative stress and vascularization deficiency in the perifollicular microenvironment provoke the premature senescence of hair follicles, limiting the transformation of hair growth cycle from the telogen to the anagen phase; (2) The amount of drug delivered to the perifollicular region located in the deep dermis is very limited for passive drug delivery systems. Herein, we developed a gas-propelled microneedle patch integrated with ferrum-chelated puerarin/quercetin nanoparticles (PQFN) to increase drug accumulation in hair follicles and reshape the perifollicular microenvironment for improved hair-regenerating effects. PQFN can rejuvenate testosterone (Tes)-induced senescence of dermal papilla cells by scavenging ROS, restoring mitochondrial function, regulating signaling pathways related to hair regeneration, and upregulating hair growth-promoting genes. PQFN more efficiently promoted endothelial cell proliferation, migration, and tube formation than ferrum-chelated quercetin nanoparticles (QFN) because of puerarin's proangiogenic effects. Compared with passive MNs, gas-propelled MNs promoted drug diffusion and permeation into deeper skin layers, resulting in significantly higher drug accumulation in hair follicles. Pharmacodynamic studies on an AGA mouse model further showed that PQFN-loaded active MNs achieved higher hair coverage by alleviating oxidative stress, promoting angiogenesis, and rejuvenating senescent cells. Therefore, this study presents a novel "anti-hair follicle aging" treatment strategy for AGA.

Progress on mitochondria and hair follicle development in androgenetic alopecia: relationships and therapeutic perspectives

Hair loss has long been a significant concern for many individuals. Recent studies have indicated that mitochondria play a more crucial role in hair loss than previously recognized. This review summarizes the connection between mitochondrial dysfunction and hair follicle development, outlines the links between diseases related to mitochondrial disorders and hair issues, and highlights the influence of mitochondrial dysfunction on androgenetic alopecia. We discuss the cellular and signaling mechanisms associated with hair loss and examine how mitochondrial dysfunction, such as insufficient energy supply, signaling irregularities, protein/gene abnormalities, and programmed cell death, can hinder the normal proliferation, differentiation, and growth of hair follicle cells. Furthermore, we discuss current treatment approaches and potential innovative therapies, including mitochondrion-targeting drugs and advanced techniques that directly target hair follicle cells, providing fresh insights into the crucial role of mitochondria in maintaining hair follicle health and managing hair disorders. Furthermore, this review explores future therapeutic strategies and proposes that mitochondrial research could lead to groundbreaking treatments for hair loss, thus providing optimism and new avenues for the treatment of individuals experiencing hair loss. This review not only underscores the central importance of mitochondria in hair health but also emphasizes the importance of advancing research and treatment in this field.

Beyond skin deep: Revealing the essence of iPS cell-generated skin organoids in regeneration

Various methods have been used for in vivo and in vitro skin regeneration, including stem cell therapy, tissue engineering, 3D printing, and platelet-rich plasma (PRP) injection therapy. However, these approaches are rooted in the existing knowledge of skin structures, which overlook the normal physiological processes of skin development and fall short of replicating the skin's regenerative processes outside the body. This comprehensive review primarily focuses on skin organoids derived from human pluripotent stem cells, which have the capacity to regenerate human skin tissue by restoring the embryonic skin structure, thus offering a novel avenue for producing in vitro skin substitutes. Furthermore, they contribute to the repair of damaged skin lesions in patients with systemic sclerosis or severe burns. Particular emphasis will be placed on the origins, generations, and applications of skin organoids, especially in dermatology, and the challenges that must be addressed before clinical implementation.

Blue light inhibits cell viability and proliferation in hair follicle stem cells and dermal papilla cells

Hair loss is a prevalent issue worldwide, which, though not life-threatening, can result in psychological problems, low self-esteem, and social anxiety. Previous studies have shown that ultraviolet radiation can have negative effects on hair follicle cells, leading to hair loss, while the impact of blue light on hair and hair follicle has largely been overlooked. This study aimed to examine the effects of blue light on hair follicle stem cells (HFSCs) and primary dermal papilla cells (DPCs), which are essential components of hair follicles. Human HFSCs and primary DPCs were exposed to blue light (457 nm) at various intensities (1, 4, 8, and 16 mW/cm2) for 3 days. Subsequently, cell viability, cell proliferation, and intracellular reactive oxygen species (ROS) were assessed. The results showed that blue light (457 nm) significantly reduced the cell viability and proliferation of HFSCs and DPCs in vitro, with the inhibition being intensity-dependent. Additionally, blue light triggered the overproduction of ROS in the DPCs. While the exact mechanisms by which blue light affects hair follicle cells remain unclear, these findings suggest that blue light could impede the growth of these cells. This insight may offer a new approach to protecting hair by avoiding exposure to high-intensity blue light.

Autophagy Dysfunction: The Kernel of Hair Loss?

Autophagy is recognized as a crucial regulatory process, instrumental in the removal of senescent, dysfunctional, and damaged cells. Within the autophagic process, lysosomal digestion plays a critical role in the elimination of impaired organelles, thus preserving fundamental cellular metabolic functions and various biological processes. Mitophagy, a targeted autophagic process that specifically focuses on mitochondria, is essential for sustaining cellular health and energy balance. Therefore, a deep comprehension of the operational mechanisms and implications of autophagy and mitophagy is vital for disease prevention and treatment. In this context, we examine the role of autophagy and mitophagy during hair follicle cycles, closely scrutinizing their potential association with hair loss. We also conduct a thorough review of the regulatory mechanisms behind autophagy and mitophagy, highlighting their interaction with hair follicle stem cells and dermal papilla cells. In conclusion, we investigate the potential of manipulating autophagy and mitophagy pathways to develop innovative therapeutic strategies for hair loss.

Ex Vivo Human Skin: An Alternative Test System for Skin Irritation and Corrosion Assays

Native human skin has been reported in the literature as being an important experimental model for studying skin biology. Studies performed by our group have shown that ex vivo skin, from elective plastic surgery, maintains the biological characteristics of native skin under specific culture conditions. As such, it might be a feasible model for the safety and efficacy testing of topical substances. While Brazil is at the forefront of global regulation implementation, Brazilian researchers are not always able to transfer certain widely used protocols to their laboratories, particularly protocols that involve the use of reconstructed tissues with limited viability, such as those for skin corrosion (OECD TG 431) and irritation testing (OECD TG 439). In this study, we investigated the applicability of the ex vivo skin model to the evaluation of irritation and corrosion potential of a number of proficiency substances described in TG 431 and TG 439. The skin fragments were standardised in size and diameter, and placed into cell culture inserts. The experimental protocol was conducted according to TG 431 and TG 439. The results obtained show that ex vivo skin could represent a promising tool for the evaluation of irritation and corrosion potential of substances (subject to inclusion and exclusion criteria), as recommended by OECD guidelines. While this is a proof-of-concept study, the use of ex vivo skin should be considered for such testing.