The Phytocannabinoid (–)-Cannabidiol Operates as a Complex, Differential Modulator of Human Hair Growth: Anti-Inflammatory Submicromolar versus Hair Growth Inhibitory Micromolar Effects

Comprehensive Insight into Cutaneous Application of Hemp

Known for its natural bio-compounds and therapeutic properties, hemp is being utilized in the development of skin products. These products offer a wide range of applications and benefits in the fields of natural bio-compounds, pharmaceutical technology, topical delivery systems, and cosmeceuticals. This manuscript deals with hemp actives, such as cannabinoids, terpenes, and flavonoids, and their diverse biological properties relative to topical application, including anti-inflammatory, antimicrobial, and antioxidant effects. Also, the paper reviews strategies to overcome poor penetration of hemp actives, as well as the integration of hemp actives in cosmeceuticals that provide natural and sustainable alternatives to traditional skincare products offering a range of benefits, including anti-aging, moisturizing, and soothing properties. The review aims to provide a comprehensive understanding of the development and manufacturing processes of skin products containing hemp actives. By delving into the science behind hemp-based products, the paper provides valuable insights into the potential of hemp as a versatile ingredient in the pharmaceutical and cosmetic industries. The utilization of hemp in these innovative products not only offers therapeutic benefits but also promotes natural and sustainable approaches to skincare.

The Multifaceted Functions of TRPV4 and Calcium Oscillations in Tissue Repair

The transient receptor potential vanilloid 4 (TRPV4) specifically functions as a mechanosensitive ion channel and is responsible for conveying changes in physical stimuli such as mechanical stress, osmotic pressure, and temperature. TRPV4 enables the entry of cation ions, particularly calcium ions, into the cell. Activation of TRPV4 channels initiates calcium oscillations, which trigger intracellular signaling pathways involved in a plethora of cellular processes, including tissue repair. Widely expressed throughout the body, TRPV4 can be activated by a wide array of physicochemical stimuli, thus contributing to sensory and physiological functions in multiple organs. This review focuses on how TRPV4 senses environmental cues and thereby initiates and maintains calcium oscillations, critical for responses to organ injury, tissue repair, and fibrosis. We provide a summary of TRPV4-induced calcium oscillations in distinct organ systems, along with the upstream and downstream signaling pathways involved. In addition, we delineate current animal and disease models supporting TRPV4 research and shed light on potential therapeutic targets for modulating TRPV4-induced calcium oscillation to promote tissue repair while reducing tissue fibrosis.

Cannabinoids and Their Receptors in Skin Diseases

The therapeutic application of cannabinoids has gained traction in recent years. Cannabinoids interact with the human endocannabinoid system in the skin. A large body of research indicates that cannabinoids could hold promise for the treatment of eczema, psoriasis, acne, pruritus, hair disorders, and skin cancer. However, most of the available data are at the preclinical stage. Comprehensive, large-scale, randomized, controlled clinical trials have not yet been fully conducted. In this article, we describe new findings in cannabinoid research and point out promising future research areas.

Cannabinoid Compounds as a Pharmacotherapeutic Option for the Treatment of Non-Cancer Skin Diseases

The endocannabinoid system has been shown to be involved in various skin functions, such as melanogenesis and the maintenance of redox balance in skin cells exposed to UV radiation, as well as barrier functions, sebaceous gland activity, wound healing and the skin's immune response. In addition to the potential use of cannabinoids in the treatment and prevention of skin cancer, cannabinoid compounds and derivatives are of interest as potential systemic and topical applications for the treatment of various inflammatory, fibrotic and pruritic skin conditions. In this context, cannabinoid compounds have been successfully tested as a therapeutic option for the treatment of androgenetic alopecia, atopic and seborrhoeic dermatitis, dermatomyositis, asteatotic and atopic eczema, uraemic pruritis, scalp psoriasis, systemic sclerosis and venous leg ulcers. This review provides an insight into the current literature on cannabinoid compounds as potential medicines for the treatment of skin diseases.

A cannabinoid Hairy-Tale: Hair loss or hair gain?

BACKGROUND

Few studies have reported on the use of cannabinoid products to treat hair loss.

AIM

This article aims to reconcile cannabinoids' impact on hair growth.

METHOD

A comprehensive and structured search was conducted in PubMed and Google Scholar on June 23, 2022.

RESULT

While cannabidiol (CBD), a phytocannabinoid, may cause hair growth, several other phytocannabinoids may lead to hair loss. Additionally, the effect of CBD on hair growth may be concentration-dependent. CBD may cause hair loss at high concentrations (≥10 μM). Therefore, the concentration of CBD needs to be adjusted so that it is optimal for hair growth. One trial found that once-daily application of CBD-rich topical cannabis extract for 6 months increased nonvellus hair count by approximately 93.5% in 35 Caucasian AGA patients: 28 males aged 28-72 years [average 43 years] and 7 females aged 46-76 years [average 61 years]. Each application contained 3-4 mg of CBD. The CBD-rich topical cannabis extract was prepared by ultra-pulverizing Cannabis sativa [hemp] flower into a green chalk-like powder [10.78% CBD and 0.21% tetrahydrocannabinol] and then infusing the powder into a lanolin paste and Emu oil carrier.

CONCLUSION

Topical CBD preparations require further studies to establish their safety and efficacy profile. An ideal topical cannabinoid preparation should contain CBD at the right concentration and lack other phytocannabinoid adulterants.

Effects of Rare Phytocannabinoids on the Endocannabinoid System of Human Keratinocytes

The decriminalization and legalization of cannabis has paved the way for investigations into the potential of the use of phytocannabinoids (pCBs) as natural therapeutics for the treatment of human diseases. This growing interest has recently focused on rare (less abundant) pCBs that are non-psychotropic compounds, such as cannabigerol (CBG), cannabichromene (CBC), Δ⁹-tetrahydrocannabivarin (THCV) and cannabigerolic acid (CBGA). Notably, pCBs can act via the endocannabinoid system (ECS), which is involved in the regulation of key pathophysiological processes, and also in the skin. In this study, we used human keratinocytes (HaCaT cells) as an in vitro model that expresses all major ECS elements in order to systematically investigate the effects of CBG, CBC, THCV and CBGA. To this end, we analyzed the gene and protein expression of ECS components (receptors: CB₁, CB₂, GPR55, TRPV1 and PPARα/γ/δ; enzymes: NAPE-PLD, FAAH, DAGLα/β and MAGL) using qRT-PCR and Western blotting, along with assessments of their functionality using radioligand binding and activity assays. In addition, we quantified the content of endocannabinoid(-like) compounds (AEA, 2-AG, PEA, etc.) using UHPLC-MS/MS. Our results demonstrated that rare pCBs modulate the gene and protein expression of distinct ECS elements differently, as well as the content of endocannabinoid(-like) compounds. Notably, they all increased CB_1/2 binding, TRPV1 channel stimulation and FAAH and MAGL catalytic activity. These unprecedented observations should be considered when exploring the therapeutic potential of cannabis extracts for the treatment of human skin diseases.

Cannabinoids for skin diseases and hair regrowth

The use of cannabis for skin diseases and hair regrowth is at the preliminary stage.

LEGALIZATION

Many countries have approved cannabis for medical use; however, four countries Canada, Uruguay, South Africa, and Georgia have legalized it for both medical and recreational purposes.

THE ENDOCANNABINOID SYSTEM

The endocannabinoid system may maintain skin homeostasis; two notable endocannabinoids include 2-Arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA).

ROUTES OF ADMINISTRATION AND PHARMACOKINETICS

Topical cannabinoids can avoid the first-pass metabolism and reduce respiratory side effects; however, the high hydrophobicity of cannabinoids may hinder percutaneous absorption.

SKIN DISORDERS AND HAIR GROWTH

Human clinical studies suggest that cannabinoids may be used in eczema, acne, pruritus, and systemic sclerosis treatment. Cannabidiol (CBD) may enhance hair growth via multiple mechanisms.

SAFETY

Topical cannabis may cause mild side effects such as pruritus, burning, erythema, and stinging; they are relatively safer than inhalation and oral cannabis. Cannabis use may be associated with allergic symptoms and reduced immune response to live vaccination.

CANNABINOIDS IN PRACTICE

Despite growing interest, dermatologists should be cautious prescribing cannabinoids due to insufficient clinical data on both efficacy and safety.

Regulatory Effect of Cannabidiol (CBD) on Decreased β-Catenin Expression in Alopecia Models by Testosterone and PMA Treatment in Dermal Papilla Cells

Objectives

The hair follicle is composed of more than 20 kinds of cells, and mesoderm derived dermal papilla cells and keratinocytes cooperatively contribute hair growth via Wnt/β-catenin signaling pathway. We are to investigate β-catenin expression and regulatory mechanism by CBD in alopecia hair tissues and dermal papilla cells.

Methods

We performed structural and anatomical analyses on alopecia patients derived hair tissues using microscopes. Pharmacological effect of CBD was evaluated by β-catenin expression using RT-PCR and immunostaining experiment.

Results

Morphological deformation and loss of cell numbers in hair shaft were observed in alopecia hair tissues. IHC experiment showed that loss of β-catenin expression was shown in inner shaft of the alopecia hair tissues, indicating that β-catenin expression is a key regulatory function during alopecia progression. Consistently, β-catenin expression was decreased in testosterone or PMA treated dermal papilla cells, suggesting that those treatments are referred as a model on molecular mechanism of alopecia using dermal papilla cells. RT-PCR and immunostaining experiments showed that β-catenin expression was decreased in RNA level, as well as decreased β-catenin protein might be resulted from ubiquitination. However, CBD treatment has no changes in gene expression including β-catenin, but the decreased β-catenin expression by testosterone or PMA was restored by CBD pretreatment, suggesting that potential regulatory effect on alopecia induction of testosterone and PMA.

Conclusion

CBD might have a modulating function on alopecia caused by hormonal or excess of signaling pathway, and be a promising application for on alopecia treatment.

Efficacy and Tolerability of a Shampoo Containing Broad-Spectrum Cannabidiol in the Treatment of Scalp Inflammation in Patients with Mild to Moderate Scalp Psoriasis or Seborrheic Dermatitis

Introduction

Scalp inflammation is commonly associated with scalp psoriasis or seborrheic dermatitis. It can aggravate the progression of androgenetic alopecia and cause troublesome itching and burning. Here, we evaluate the efficacy of a shampoo containing 0.075% broad-spectrum cannabidiol in 50 subjects with mild to moderate scalp psoriasis or seborrheic dermatitis.

Methods

Inflammation was assessed by evaluating the density of twisted/glomerular or arborizing vessels by trichoscopy using a 6-point scale at baseline and day 14. Symptoms of itching/burning sensation, clinical evaluation of erythema/scaling, overall tolerability, and subject satisfaction were evaluated using 10-point scales.

Results

There were significant reductions in arborizing vessel/twisted capillary inflammation and scaling by day 14. Severity scores reduced from 2.3 ± 0.1, 2.6 ± 0.1, and 3.6 ± 0.1, respectively, to 0.5 ± 0.05, 0.8 ± 0.05, and 0.6 ± 0.05 (all p < 0.0001). Symptom scores of itching and burning also reduced significantly from 6.9 ± 0.1 to 4.5 ± 0.1 to 1.5 ± 0.05 and 1.0 ± 0.05 (both p < 0.0001). Severity of erythema and scaling was also significantly reduced from 5.5 ± 0.1 and 7.0 ± 0.1, respectively, to 1.3 ± 0.05 and 1.6 ± 0.05 (both p < 0.0001). Tolerability and subject satisfaction were both excellent. There were no significant differences in treatment effect, tolerability, or subject satisfaction between men and women.

Discussion/Conclusion

Replacing current shampooing practices with a broad-spectrum cannabidiol-containing shampoo significantly reduces both severity and symptoms of scalp inflammation within 2 weeks, with excellent tolerability and treatment satisfaction in subjects with mild to moderate scalp psoriasis or seborrheic dermatitis.

Translational Neuroendocrinology of Human Skin: Concepts and Perspectives

Human skin responds to numerous neurohormones, neuropeptides, and neurotransmitters that reach it via the vasculature or skin nerves, and/or are generated intracutaneously, thus acting in a para- and autocrine manner. This review focuses on how neurohormones impact on human skin physiology and pathology. We highlight basic concepts, major open questions, and translational research perspectives in cutaneous neuroendocrinology and argue that greater emphasis on neuroendocrine human skin research will foster the development of novel dermatological therapies. Furthermore, human skin and its appendages can be used as highly accessible and clinically relevant model systems for probing nonclassical, ancestral neurohormone functions. This calls for close interdisciplinary collaboration between dermatologists, skin biologists, neuroendocrinologists, and neuropharmacologists.

Mitochondrial energy metabolism is negatively regulated by cannabinoid receptor 1 in intact human epidermis

Epidermal energy metabolism is relevant to skin physiology, ageing and photodamage. While selected hormones stimulate epidermal keratinocyte mitochondrial activity, its negative regulation remains unknown. In several cell types, cannabinoid receptor 1 (CB₁ ) is expressed both on the cell membrane (cmCB₁ ) and on the mitochondrial outer membrane (mtCB₁ ), where its stimulation directly suppresses mitochondrial functions. In the current pilot study, we investigated if CB₁ is a negative regulator of human epidermal energy metabolism under physiological conditions. Using organ-cultured full-thickness human skin specimens of healthy individuals, we showed that antagonizing the homeostatic CB₁ signalling by the administration of the CB₁ inverse agonist AM251 increased respiratory chain complex I and II/IV activity. The effect was CB₁ -dependent, since the CB₁ -selective agonist arachidonyl-2'-chloroethylamide could prevent the effect. Moreover, the phenomenon was also reproduced by siRNA-mediated down-regulation of CB₁ . As revealed by the unaltered expression of several relevant markers (TFAM, VDAC1, MTCO1 and NDUFS4), modulation of CB₁ signalling had no effect on the epidermal mitochondrial mass. Next, by using immunoelectron microscopy, we found that human epidermal keratinocytes express both cmCB₁ and mtCB₁ . Finally, by using equipotent extracellularly restricted (hemopressin) as well as cell-permeable (AM251) inverse agonists, we found that mitochondrial activity is most likely exclusively regulated by mtCB₁ . Thus, our data identify mtCB₁ as a novel negative regulator of keratinocyte mitochondrial activity in intact human epidermis, and raise the question, whether topical therapeutic interventions capable of selectively activating mtCB₁ can reduce excessive mitochondrial ROS production resulting from dysregulated mitochondrial activity during skin ageing or photodamage.

GPR119 Is a Potent Regulator of Human Sebocyte Biology

We have shown previously that endocannabinoids promote sebaceous lipogenesis, and sebocytes are involved in the metabolism of the endocannabinoid-like substance oleoylethanolamide (OEA). OEA is an endogenous activator of GPR119, a recently deorphanized receptor, which currently is being investigated as a promising antidiabetic drug target. In this study, we investigated the effects of OEA as well as the expression and role of GPR119 in human sebocytes. We found that OEA promoted differentiation of human SZ95 sebocytes (elevated lipogenesis, enhanced granulation, and the induction of early apoptotic events), and it switched the cells to a proinflammatory phenotype (increased expression and release of several proinflammatory cytokines). Moreover, we could also demonstrate that GPR119 was expressed in human sebocytes, and its small interfering RNA-mediated gene silencing suppressed OEA-induced sebaceous lipogenesis, which was mediated via c-Jun N-terminal kinase, extracellular signal-regulated kinase 1/2, protein kinase B, and CRE-binding protein activation. Finally, our pilot data demonstrated that GPR119 was downregulated in the sebaceous glands of patients with acne, arguing that GPR119 signaling may indeed be disturbed in acne. Collectively, our findings introduce the OEA/GPR119 signaling as a positive regulator of sebocyte differentiation and highlight the possibility that dysregulation of this pathway may contribute to the development of seborrhea and acne.