The endocannabinoid system of the skin in health and disease: novel perspectives and therapeutic opportunities

Metabolomic and lipidomic fingerprints in inflammatory skin diseases - Systemic illumination of atopic dermatitis, hidradenitis suppurativa and plaque psoriasis

Auto-inflammatory skin diseases place considerable symptomatic and emotional burden on the affected and put pressure on healthcare expenditures. Although most apparent symptoms manifest on the skin, the systemic inflammation merits a deeper analysis beyond the surface. We set out to identify systemic commonalities, as well as differences in the metabolome and lipidome when comparing between diseases and healthy controls. Lipidomic and metabolomic LC-MS profiling was applied, using plasma samples collected from patients suffering from atopic dermatitis, plaque-type psoriasis or hidradenitis suppurativa or healthy controls. Plasma profiles revealed a notable shift in the non-enzymatic anti-oxidant defense in all three inflammatory disorders, placing cysteine metabolism at the center of potential dysregulation. Lipid network enrichment additionally indicated the disease-specific provision of lipid mediators associated with key roles in inflammation signaling. These findings will help to disentangle the systemic components of autoimmune dermatological diseases, paving the way to individualized therapy and improved prognosis.

Melanoma and cannabinoids: A possible chance for cancer treatment

The endocannabinoid system is composed by a complex and ubiquitous network of endogenous lipid ligands, enzymes for their synthesis and degradation, and receptors, which can also be stimulated by exogenous compounds, such as those derived from the Cannabis sativa. Cannabis and its bioactive compounds, including cannabinoids and non-cannabinoids, have been extensively studied in different conditions. Recent data have shown that the endocannabinoid system is responsible for maintaining the homeostasis of various skin functions such as proliferation, differentiation and release of inflammatory mediators. Because of their role in regulating these key processes, cannabinoids have been studied for the treatment of skin cancers and melanoma; their anti-tumour effects regulate skin cancer progression and are mainly related to the inhibition of tumour growth, proliferation, invasion and angiogenesis, through apoptosis and autophagy induction. This review aims at summarising the current field of research on the potential uses of cannabinoids in the melanoma field.

Cannabidiol and its application in the treatment of oral diseases: therapeutic potentials, routes of administration and prospects

Cannabidiol (CBD), one of the most important active ingredients in cannabis, has been reported to have some pharmacological effects such as antibacterial and analgesic effects, and to have therapeutic potential in the treatment of oral diseases such as oral cancer, gingivitis and periodontal diseases. However, there is a lack of relevant systematic research and reviews. Therefore, based on the etiology and clinical symptoms of several common oral diseases, this paper focuses on the therapeutic potential of CBD in periodontal diseases, pulp diseases, oral mucosal diseases, oral cancer and temporomandibular joint diseases. The pharmacological effects of CBD and the distribution and function of its receptors in the oral cavity are also summarized. In order to provide reference for future research and further clinical application of CBD, we also summarize several possible routes of administration and corresponding characteristics. Finally, the challenges faced while applying CBD clinically and possible solutions are discussed, and we also look to the future.

Anandamide modulation of monocyte-derived Langerhans cells: implications for immune homeostasis and skin inflammation

Introduction

The endocannabinoid system (ECS), named after the chemical compounds found in the cannabis plant, is a regulatory network of neurotransmitters, receptors, and enzymes that plays crucial roles in skin health and disease. Endogenous ligands of the ECS, called endocannabinoids, have proven to be important regulators of immune responses. One of the most prevalent endocannabinoids, arachidonoylethanolamide (also known as anandamide), is known for its anti-inflammatory effects. Langerhans cells (LCs) are the sole antigen-presenting cells present in the human epidermis. They serve as the first line of defense against pathogens and are essential for the skin's specific immune responses and play a critical role in maintaining tissue homeostasis; however, little is known about the effect of endocannabinoids on these cells. Our research aimed to provide the connection between monocyte-derived Langerhans cells (moLCs) and the ECS, shedding light on their collaborative roles in immune homeostasis and inflammation.

Methods

Human monocytes were differentiated into moLCs using established protocols. Anandamide was applied during the differentiation process to test its effect on the viability, marker expression, and cytokine production of the cells, as well as in short term treatments for intracellular calcium measurement. TLR ligands applied after the differentiation protocol were used to activate moLCs. The impact of anandamide on the functionality of moLCs was further assessed using differential gene expression analysis of bulk RNA-Seq data, moLC-T cell cocultures, while ELISpot was employed to determine polarization of T cells activated in the aforementioned cocultures.

Results

Anandamide did not significantly affect the viability of moLCs up to 10 µM. When applied during the differentiation process it had only a negligible effect on CD207 expression, the prototypic marker of LCs; however, there was an observed reduction in CD1a expression by moLCs. Anandamide had no significant effects on the maturation status of moLCs, nor did it affect the maturation induced by TLR3 and TLR7/8 agonists. MoLCs differentiated in the presence of anandamide did however show decreased production of CXCL8, IL-6, IL-10 and IL-12 cytokines induced by TLR3 and TLR7/8 activation. Anandamide-treated moLCs showed an increased capability to activate naïve T cells; however, not to the level seen with combined TLR agonism. RNA sequencing analysis of moLCs differentiated with anandamide showed modest changes compared to control cells but did reveal an inhibitory effect on oxidative phosphorylation specifically in activated moLCs. Anandamide also promoted the polarization of naïve T cells towards a Th1 phenotype.

Discussion

Our results show that anandamide has nuanced effects on the differentiation, maturation, cytokine secretion, metabolism and function of activated moLCs. Among these changes the decrease in CD1a expression on moLCs holds promise to selectively dampen inflammation induced by CD1a restricted T cells, which have been implicated as drivers of inflammation in common inflammatory skin conditions such as psoriasis, atopic dermatitis and contact dermatitis.

The Perspective of Cannabidiol in Psoriasis Therapy

Psoriasis is a chronic skin condition that can significantly impact the quality of life of those affected. As an autoimmune disease, it can lead to itchy, painful, and scaly patches on the skin. Although various treatments, including topical creams, phototherapy, and systemic medications, are currently available, they may not always offer effective relief and can have side effects. Researchers have thus been exploring the potential benefits of non-psychoactive compounds such as CBD, found in Cannabis sativa plants, for treating psoriasis. CBD treatment may reduce inflammation, oxidative stress, itching, abnormal proliferation of keratinocytes, and may increase hydration. This review aims to provide an overview of the existing literature on the potential uses of CBD for psoriasis treatment.

Revitalizing the skin: Exploring the role of barrier repair moisturizers

BACKGROUND

Moisturizers are designed to maintain skin health and treat dermatological conditions associated with impaired skin barrier function. However, differences in their composition account for the differences in their effect.

AIMS

This narrative review aims to discuss the role of barrier repair moisturizers, highlight the role of different components in a moisturizer and their role in impaired skin conditions (e.g., dry, itchy, inflamed, sensitive skin, atopic eczema), and thereby empower dermatologists and pediatricians in selecting the right moisturizer.

METHODS

PubMed, Embase, and Scopus electronic databases were searched from January 2000 to June 2023 for publications on skin barrier repair and use of barrier repair moisturizers for the treatment of dry, itchy, inflamed, sensitive skin, or atopic eczema. Studies conducted in humans, published in English for which full texts were freely available were included.

RESULTS

The structure and composition of lipid lamellae within the stratum corneum play an important role in maintaining an effective skin barrier and protecting the body from various external assaults. Endocannabinoid mediators play an active role in maintaining skin barrier function. Moisturizers containing physiological lipids and functional ingredients (e.g., endocannabinoids such as palmitoylethanolamide [PEA]) and based on the principles of biomimic technology are demonstrated to be beneficial for the management of conditions associated with a disrupted skin barrier.

CONCLUSIONS

Moisturizer based on the innovative biomimic formulation has good cosmetic efficacy and is generally well tolerated, and the addition of PEA might represent a new generation of compounds that may be beneficial for long-term management of impaired skin conditions.

Photo-neuro-immuno-endocrinology: How the ultraviolet radiation regulates the body, brain, and immune system

Ultraviolet radiation (UVR) is primarily recognized for its detrimental effects such as cancerogenesis, skin aging, eye damage, and autoimmune disorders. With exception of ultraviolet B (UVB) requirement in the production of vitamin D3, the positive role of UVR in modulation of homeostasis is underappreciated. Skin exposure to UVR triggers local responses secondary to the induction of chemical, hormonal, immune, and neural signals that are defined by the chromophores and extent of UVR penetration into skin compartments. These responses are not random and are coordinated by the cutaneous neuro-immuno-endocrine system, which counteracts the action of external stressors and accommodates local homeostasis to the changing environment. The UVR induces electrical, chemical, and biological signals to be sent to the brain, endocrine and immune systems, as well as other central organs, which in concert regulate body homeostasis. To achieve its central homeostatic goal, the UVR-induced signals are precisely computed locally with transmission through nerves or humoral signals release into the circulation to activate and/or modulate coordinating central centers or organs. Such modulatory effects will be dependent on UVA and UVB wavelengths. This leads to immunosuppression, the activation of brain and endocrine coordinating centers, and the modification of different organ functions. Therefore, it is imperative to understand the underlying mechanisms of UVR electromagnetic energy penetration deep into the body, with its impact on the brain and internal organs. Photo-neuro-immuno-endocrinology can offer novel therapeutic approaches in addiction and mood disorders; autoimmune, neurodegenerative, and chronic pain-generating disorders; or pathologies involving endocrine, cardiovascular, gastrointestinal, or reproductive systems.

Stability, biofunctional, and antimicrobial characteristics of cannabidiol isolate for the design of topical formulations

Cannabidiol (CBD) is a high-value natural compound of Cannabis Sativa plant. It is a non-psychotropic phytocannabinoid, attracting significant attention as a multifunctional active ingredient for topical applications. Although it is demonstrated that CBD can be used for specific dermatological ailments, reliable data on functionalities are limited. The present study aimed to investigate the structural stability, biofunctionality, and antimicrobial characteristics of CBD isolate to assist in the design of various topical formulations. The stability of CBD in solid and solubilized states was assessed to establish storage and formulation conditions. The performance of CBD solubilized in organic and aqueous media was evaluated for free radical scavenging, tyrosinase, and collagenase enzyme inhibition, which showed good prospects for the ingredient. The antimicrobial activity of solubilized CBD was evaluated against Gram-negative (E. coli, P. aeruginosa), Gram-positive bacterial strains (S. aureus, S. epidermidis, C. acnes), and fungal strains (C. albicans, M. furfur) using agar well diffusion and broth microdilution methods. Due to the presence of surfactants in CBD aqueous solution, it displayed a lack of antimicrobial activity against all the tested microorganisms. CBD solubilized in an organic medium showed no activity against Gram-negative bacterial strains but higher activity against tested Gram-positive bacterial and fungal strains.

Cannabinoids for the treatment of autoimmune and inflammatory skin diseases: A systematic review

In recent years, the medical use of cannabinoids has attracted growing attention worldwide. In particular, anti-inflammatory properties of cannabinoids led to their emergence as potential therapeutic options for autoimmune and inflammatory disorders. Recent studies have also shown that cannabinoid receptors are widely expressed and have endogenous ligands in the skin, suggesting that the skin has its own endocannabinoid system. The aim of this review is to discuss the potential therapeutic effects of cannabinoids in autoimmune and inflammatory skin diseases. Following an overview of cannabinoids and the endocannabinoid system, we describe the cellular and molecular mechanisms of cannabinoids in skin health and disease. We then review the clinical studies of cannabinoids in autoimmune and inflammatory skin diseases including systemic sclerosis (SSc), dermatomyositis (DM), psoriasis (Pso) and atopic dermatitis (AD). A primary literature search was conducted in July 2023, using PubMed and Web of Science. A total of 15 articles were included after excluding reviews, non-human studies and in vitro studies from 389 non-duplicated articles. Available evidence suggests that cannabinoids may be beneficial for SSc, DM, Pso and AD. However, further studies, ideally randomized controlled trials, are needed to further evaluate the use of cannabinoids in autoimmune and inflammatory skin diseases.

Rationalizing a prospective coupling effect of cannabinoids with the current pharmacotherapy for melanoma treatment

Melanoma is one of the leading fatal forms of cancer, yet from a treatment perspective, we have minimal control over its reoccurrence and resistance to current pharmacotherapies. The endocannabinoid system (ECS) has recently been accepted as a multifaceted homeostatic regulator, influencing various physiological processes across different biological compartments, including the skin. This review presents an overview of the pathophysiology of melanoma, current pharmacotherapy used for treatment, and the challenges associated with the different pharmacological approaches. Furthermore, it highlights the utility of cannabinoids as an additive remedy for melanoma by restoring the balance between downregulated immunomodulatory pathways and elevated inflammatory cytokines during chronic skin conditions as one of the suggested critical approaches in treating this immunogenic tumor. This article is categorized under: Cancer > Molecular and Cellular Physiology.

Targeting Fatty Acid Amide Hydrolase Counteracts the Epithelial-to-Mesenchymal Transition in Keratinocyte-Derived Tumors

The endocannabinoid system regulates physiological processes, and the modulation of endogenous endocannabinoid (eCB) levels is an attractive tool to contrast the development of pathological skin conditions including cancers. Inhibiting FAAH (fatty acid amide hydrolase), the degradation enzyme of the endocannabinoid anandamide (AEA) leads to the increase in AEA levels, thus enhancing its biological effects. Here, we evaluated the anticancer property of the FAAH inhibitor URB597, investigating its potential to counteract epithelial-to-mesenchymal transition (EMT), a process crucially involved in tumor progression. The effects of the compound were determined in primary human keratinocytes, ex vivo skin explants, and the squamous carcinoma cell line A431. Our results demonstrate that URB597 is able to hinder the EMT process by downregulating mesenchymal markers and reducing migratory potential. These effects are associated with the dampening of the AKT/STAT3 signal pathways and reduced release of pro-inflammatory cytokines and tumorigenic lipid species. The ability of URB597 to contrast the EMT process provides insight into effective approaches that may also include the use of FAAH inhibitors for the treatment of skin cancers.

Chronic wound-related pain, wound healing and the therapeutic potential of cannabinoids and endocannabinoid system modulation

Chronic wounds represent a significant burden on the individual, and the healthcare system. Individuals with chronic wounds report pain to be the most challenging aspect of living with a chronic wound, with current therapeutic options deemed insufficient. The cutaneous endocannabinoid system is an important regulator of skin homeostasis, with evidence of system dysregulation in several cutaneous disorders. Herein, we describe the cutaneous endocannabinoid system, chronic wound-related pain, and comorbidities, and review preclinical and clinical evidence investigating endocannabinoid system modulation for wound-related pain and wound healing. Based on the current literature, there is some evidence to suggest efficacy of endocannabinoid system modulation for promotion of wound healing, attenuation of cutaneous disorder-related inflammation, and for the management of chronic wound-related pain. However, there is 1) a paucity of preclinical studies using validated models, specific for the study of chronic wound-related pain and 2) a lack of randomised control trials and strong clinical evidence relating to endocannabinoid system modulation for wound-related pain. In conclusion, while there is some limited evidence of benefit of endocannabinoid system modulation in wound healing and wound-related pain management, further research is required to better realise the potential of targeting the endocannabinoid system for these therapeutic applications.

Goods and Bads of the Endocannabinoid System as a Therapeutic Target: Lessons Learned after 30 Years

The cannabis derivative marijuana is the most widely used recreational drug in the Western world and is consumed by an estimated 83 million individuals (∼3% of the world population). In recent years, there has been a marked transformation in society regarding the risk perception of cannabis, driven by its legalization and medical use in many states in the United States and worldwide. Compelling research evidence and the Food and Drug Administration cannabis-derived cannabidiol approval for severe childhood epilepsy have confirmed the large therapeutic potential of cannabidiol itself, Δ9-tetrahydrocannabinol and other plant-derived cannabinoids (phytocannabinoids). Of note, our body has a complex endocannabinoid system (ECS)-made of receptors, metabolic enzymes, and transporters-that is also regulated by phytocannabinoids. The first endocannabinoid to be discovered 30 years ago was anandamide (N-arachidonoyl-ethanolamine); since then, distinct elements of the ECS have been the target of drug design programs aimed at curing (or at least slowing down) a number of human diseases, both in the central nervous system and at the periphery. Here a critical review of our knowledge of the goods and bads of the ECS as a therapeutic target is presented to define the benefits of ECS-active phytocannabinoids and ECS-oriented synthetic drugs for human health. SIGNIFICANCE STATEMENT: The endocannabinoid system plays important roles virtually everywhere in our body and is either involved in mediating key processes of central and peripheral diseases or represents a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of the components of this complex system, and in particular of key receptors (like cannabinoid receptors 1 and 2) and metabolic enzymes (like fatty acid amide hydrolase and monoacylglycerol lipase), will advance our understanding of endocannabinoid signaling and activity at molecular, cellular, and system levels, providing new opportunities to treat patients.

Effects of combined cannabidiol (CBD) and hops (Humulus lupulus) terpene extract treatment on RAW 264.7 macrophage viability and inflammatory markers

This study investigates the potential of cannabidiol (CBD), one major cannabinoid of the plant Cannabis sativa, alone and in combination with a terpene-enriched extract from Humulus lupulus ("Hops 1"), on the LPS-response of RAW 264.7 macrophages as an established in vitro model of inflammation. With the present study, we could support earlier findings of the anti-inflammatory potential of CBD, which showed a dose-dependent [0-5 µM] reduction in nitric oxide and tumor necrosis factor-alpha (TNF-α) released by LPS-stimulated RAW 264.7 macrophages. Moreover, we observed an additive anti-inflammatory effect after combined CBD [5 µM] and hops extract [40 µg/mL] treatment. The combination of CBD and Hops 1 showed effects in LPS-stimulated RAW 264.7 cells superior to the single substance treatments and akin to the control hydrocortisone. Furthermore, cellular CBD uptake increased dose-dependently in the presence of terpenes from Hops 1 extract. The anti-inflammatory effect of CBD and its cellular uptake positively correlated with terpene concentration, as indicated by comparison with a hemp extract containing both CBD and terpenes. These findings may contribute to the postulations for the so-called "entourage effect" between cannabinoids and terpenes and support the potential of CBD combined with phytomolecules from a non-cannabinoid source, such as hops, for the treatment of inflammatory diseases.

Role of Type I Cannabinoid Receptor in Sensory Neurons in Psoriasiform Skin Inflammation and Pruritus

Type I cannabinoid receptor (CB1R) has been reported to exhibit favorable anti-inflammation and antipruritus effects against inflammation-based skin diseases, but the specific mechanism remains to be explored. In this study, we found that the activation of CB1R significantly relieved the scratching behavior and skin inflammation in a psoriatic mouse model, whereas CB1R antagonist aggravated these symptoms. Because the expression of CB1R was abundant in dorsal root ganglia, we constructed mice with conditional CB1R knockout in primary sensory neurons and found that imiquimod-induced psoriasiform inflammation and itch were both worsened in CB1R-conditional knockout mice. Next, we observed that the CB1R was mostly located in peptidergic neurons, and deletion of CB1R in primary sensory neurons promoted the production and release of substance P to the skin tissue. Furthermore, the elevated substance P in the skin affected the activation of extracellular signal‒regulated kinase in keratinocytes and induced the accumulation of mast cells in the dermis. Finally, we showed that blocking the substance P signal significantly alleviated the exacerbation of psoriasiform inflammation and itch caused by imiquimod in CB1R-conditional knockout mice. Together, our work reveals that CB1R in sensory neurons plays a key role in psoriasiform skin inflammation and pruritus by regulating substance P expression.

The phospholipase A2 superfamily as a central hub of bioactive lipids and beyond

In essence, "phospholipase A₂" (PLA₂) means a group of enzymes that release fatty acids and lysophospholipids by hydrolyzing the sn-2 position of glycerophospholipids. To date, more than 50 enzymes possessing PLA₂ or related lipid-metabolizing activities have been identified in mammals, and these are subdivided into several families in terms of their structures, catalytic mechanisms, tissue/cellular localizations, and evolutionary relationships. From a general viewpoint, the PLA₂ superfamily has mainly been implicated in signal transduction, driving the production of a wide variety of bioactive lipid mediators. However, a growing body of evidence indicates that PLA₂s also contribute to phospholipid remodeling or recycling for membrane homeostasis, fatty acid β-oxidation for energy production, and barrier lipid formation on the body surface. Accordingly, PLA₂ enzymes are considered one of the key regulators of a broad range of lipid metabolism, and perturbation of specific PLA₂-driven lipid pathways often disrupts tissue and cellular homeostasis and may be associated with a variety of diseases. This review covers current understanding of the physiological functions of the PLA₂ superfamily, focusing particularly on the two major intracellular PLA₂ families (Ca²⁺-dependent cytosolic PLA₂s and Ca²⁺-independent patatin-like PLA₂s) as well as other PLA₂ families, based on studies using gene-manipulated mice and human diseases in combination with comprehensive lipidomics.

Endocannabinoid and perceived stress: Association analysis of endocannabinoid levels in hair versus levels in plasma and urine

The endocannabinoid system is considered to play a role in a wide range of functions, including stress. Hair analysis of endocannabinoids presents a promising methodological advancement for the retrospective assessment of long-term cumulative endocannabinoid secretion. Despite promising pilot study results suggesting the usefulness of hair endocannabinoid assessments, it remains unclear whether hair endocannabinoid levels mirror systemic endocannabinoid levels accurately. Two independent studies were conducted to investigate to what extent hair endocannabinoid and N-Acylethanolamine levels reflect the systemic levels retrospectively. Endocannabinoid and N-Acylethanolamine levels were measured in 3 cm and 1 cm hair segments respectively, and compared with the averaged levels in multiple plasma samples collected during three months (Study I), and in multiple 24-hour urine samples collected over a month (Study II). In addition, the Perceived Stress Scale was used to assess the perceived stress throughout the studies. Against our hypothesis, no association was found between the endocannabinoid or N-Acylethanolamine levels in hair and plasma or urine. However, hair palmitoylethanolamide (PEA), oleoylethanolamide (OEA), and stearoylethanolamide (SEA) levels were positively correlated with perceived stress in Study I. The current findings suggest that hair endocannabinoid or N-Acylethanolamine levels might not accurately reflect the levels of peripheral circulating endocannabinoid or N-Acylethanolamine. Nevertheless, hair N-Acylethanolamine levels might emerge as a useful strategy in the study of some psychological phenotypes, such as stress.

Rare Phytocannabinoids Exert Anti-Inflammatory Effects on Human Keratinocytes via the Endocannabinoid System and MAPK Signaling Pathway

Increasing evidence supports the therapeutic potential of rare cannabis-derived phytocannabinoids (pCBs) in skin disorders such as atopic dermatitis, psoriasis, pruritus, and acne. However, the molecular mechanisms of the biological action of these pCBs remain poorly investigated. In this study, an experimental model of inflamed human keratinocytes (HaCaT cells) was set up by using lipopolysaccharide (LPS) in order to investigate the anti-inflammatory effects of the rare pCBs cannabigerol (CBG), cannabichromene (CBC), Δ⁹-tetrahydrocannabivarin (THCV) and cannabigerolic acid (CBGA). To this aim, pro-inflammatory interleukins (IL)-1β, IL-8, IL-12, IL-31, tumor necrosis factor (TNF-β) and anti-inflammatory IL-10 levels were measured through ELISA quantification. In addition, IL-12 and IL-31 levels were measured after treatment of HaCaT cells with THCV and CBGA in the presence of selected modulators of endocannabinoid (eCB) signaling. In the latter cells, the activation of 17 distinct proteins along the mitogen-activated protein kinase (MAPK) pathway was also investigated via Human Phosphorylation Array. Our results demonstrate that rare pCBs significantly blocked inflammation by reducing the release of all pro-inflammatory ILs tested, except for TNF-β. Moreover, the reduction of IL-31 expression by THCV and CBGA was significantly reverted by blocking the eCB-binding TRPV1 receptor and by inhibiting the eCB-hydrolase MAGL. Remarkably, THCV and CBGA modulated the expression of the phosphorylated forms (and hence of the activity) of the MAPK-related proteins GSK3β, MEK1, MKK6 and CREB also by engaging eCB hydrolases MAGL and FAAH. Taken together, the ability of rare pCBs to exert an anti-inflammatory effect in human keratinocytes through modifications of eCB and MAPK signaling opens new perspectives for the treatment of inflammation-related skin pathologies.

Beyond Pain Relief: A Review on Cannabidiol Potential in Medical Therapies

The phytocannabinoid cannabidiol (CBD) is receiving increasing attention due to its pharmacological properties. Although CBD is extracted from Cannabis sativa, it lacks the psychoactive effects of Δ9-tetrahydrocannabinol (THC) and has become an attractive compound for pharmacological uses due to its anti-inflammatory, antioxidant, anticonvulsant, and anxiolytic potential. The molecular mechanisms involved in CBD's biological effects are not limited to its interaction with classical cannabinoid receptors, exerting anti-inflammatory or pain-relief effects. Several pieces of evidence demonstrate that CBD interacts with other receptors and cellular signaling cascades, which further support CBD's therapeutic potential beyond pain management. In this review, we take a closer look at the molecular mechanisms of CBD and its potential therapeutic application in the context of cancer, neurodegeneration, and autoimmune diseases.

Hair Regrowth with Novel Hemp Extract: A Case Series

Introduction

The endocannabinoid system (ECS), discovered in the 1990s, is a system involved with maintaining cellular homeostasis by down-regulating the damaging inflammatory responses and upregulating regenerative processes. Cannabidiol (CBD), tetrahydrocannabivarin (THCV), and cannabidivarin (CBDV) are all phytocannabinoids found in varying quantities in hemp extract. These three cannabinoids have novel therapeutic effects on hair regrowth through the ECS. The method of action is different from and synergistic with current hair regrowth therapies. The three cannabinoids are fat-soluble and poorly absorbed past the epidermis, but topical application easily reaches hair follicles where they act as partial or full CB1 antagonist and agonist of transient receptor potential vanilloid-1 (TRPV1) and vanilloid receptor-4 (TRPV4). All these ECS receptors relate to hair follicle function. Blocking the CB1 receptor on the hair follicle has been shown to result in hair shaft elongation; in addition, the hair follicle cycle (anagen, catagen, and telogen phases) is controlled by TRPV1. The effects of CBD on hair growth are dose dependent and higher doses may result in premature entry into the catagen phase through a different receptor known as TRPV4. CBD has also been shown to increase Wnt signaling, which causes dermal progenitor cells to differentiate into new hair follicles and maintains anagen phase of the hair cycle.

Objective

This study was conducted on subjects with androgenetic alopecia (AGA), as follow-up to a prior published study using hemp extract high in CBD without CBDV or THCV. That study showed an average 93.5% increase in hair numbers after 6 months of use. This subsequent study is being done to determine if daily topical application of a hemp-oil high in CBD, THCV, and CBDV concentrations would result in improved hair regrowth in the area of the scalp most affected by AGA.

Materials and Methods

A case series study was done of 31 (15 men and 16 women, 27 Caucasian, 2 Asian, and 1 mixed race) subjects with AGA. They used a once-daily topical hemp extract formulation, averaging about 33 mg/day for 6 months. A hair count of the greatest area of alopecia was carried out before treatment was started and again after 6 months of treatment. To facilitate consistent hair count analysis, a permanent tattoo was placed at the point for maximum hair loss on the scalp. The subjects were also asked to qualitatively rate their psychosocial perception of "scalp coverage" improvement after the study was completed. The qualitative scale included "very unhappy," "unhappy," "neutral," "happy," and "very happy." The subjects were photographed in a standard manner before and after the study. The photographs were compared for improvements in "scalp coverage" by an independent physician. The qualitative scale included "none," "mild," "moderate," and "extensive" improvement of scalp coverage.

Results

The results revealed that all subjects had some regrowth. This ranged from 31.25% (from 16 to 21 hairs) to 2000% (from 1 to 21 hairs). The average increase was statistically significant 246% (15.07 hairs/cm2 increase) in men and 127% (16.06 hairs/cm2) in women. There were no reported adverse effects. All subjects rated their psychosocial perception of the effects of the hair loss, as "happy" or "very happy." Independent review of the photographs revealed evidence of "mild" to "extensive" scalp coverage improvements for all of the subjects.

Conclusion

Although the exact mechanism of therapeutic effects is not known, THCV and CBDV are most likely functioning as full CB1 receptor neutral antagonists and CBD is most likely functioning as a partial CB1 receptor antagonist and potentially through Wnt messaging. All three cannabinoids were functioning as TRPV1 agonists. The addition of menthol through the peppermint extract is probably acting through promoting a rapid onset of anagen phase. This topical hemp formulation was superior to oral finasteride, 5% minoxidil once daily foam and CBD topical extract alone. Since this hemp extract works through novel mechanisms entirely different from both finasteride and minoxidil, it can be used in conjunction with these current drugs and would be expected to have synergistic effects. However, safety and efficacy of this combination would be to be evaluated.

Neuroendocrine signaling in the skin with a special focus on the epidermal neuropeptides

The skin, which is comprised of the epidermis, dermis, and subcutaneous tissue, is the largest organ in the human body and it plays a crucial role in the regulation of the body's homeostasis. These functions are regulated by local neuroendocrine and immune systems with a plethora of signaling molecules produced by resident and immune cells. In addition, neurotransmitters, endocrine factors, neuropeptides, and cytokines released from nerve endings play a central role in the skin's responses to stress. These molecules act on the corresponding receptors in an intra-, juxta-, para-, or autocrine fashion. The epidermis as the outer most component of skin forms a barrier directly protecting against environmental stressors. This protection is assured by an intrinsic keratinocyte differentiation program, pigmentary system, and local nervous, immune, endocrine, and microbiome elements. These constituents communicate cross-functionally among themselves and with corresponding systems in the dermis and hypodermis to secure the basic epidermal functions to maintain local (skin) and global (systemic) homeostasis. The neurohormonal mediators and cytokines used in these communications regulate physiological skin functions separately or in concert. Disturbances in the functions in these systems lead to cutaneous pathology that includes inflammatory (i.e., psoriasis, allergic, or atopic dermatitis, etc.) and keratinocytic hyperproliferative disorders (i.e., seborrheic and solar keratoses), dysfunction of adnexal structure (i.e., hair follicles, eccrine, and sebaceous glands), hypersensitivity reactions, pigmentary disorders (vitiligo, melasma, and hypo- or hyperpigmentary responses), premature aging, and malignancies (melanoma and nonmelanoma skin cancers). These cellular, molecular, and neural components preserve skin integrity and protect against skin pathologies and can act as "messengers of the skin" to the central organs, all to preserve organismal survival.

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.

Use of Cannabis and Cannabinoids for Treatment of Cancer

The endocannabinoid system (ECS) is an ancient homeostasis mechanism operating from embryonic stages to adulthood. It controls the growth and development of many cells and cell lineages. Dysregulation of the components of the ECS may result in uncontrolled proliferation, adhesion, invasion, inhibition of apoptosis and increased vascularization, leading to the development of various malignancies. Cancer is the disease of uncontrolled cell division. In this review, we will discuss whether the changes to the ECS are a cause or a consequence of malignization and whether different tissues react differently to changes in the ECS. We will discuss the potential use of cannabinoids for treatment of cancer, focusing on primary outcome/care-tumor shrinkage and eradication, as well as secondary outcome/palliative care-improvement of life quality, including pain, appetite, sleep, and many more factors. Finally, we will complete this review with the chapter on sex- and gender-specific differences in ECS and response to cannabinoids, and equality of the access to treatments with cannabinoids.

Comparison of the in vitro Anti-Inflammatory Effect of Cannabidiol to Dexamethasone

Background

Cannabidiol (CBD) is a non-psychoactive phytocannabinoid constituent of Cannabis sativa with pain-relieving and anti-inflammatory properties. With the emphasis on natural ingredients in cosmetics, CBD has become a new cosmetic ingredient due to its ability to alleviate inflammation. However, in-depth studies that directly compare the effective mechanism and the therapeutic potential of CBD are still needed.

Purpose

The aim of the present study was to investigate the anti-inflammatory effect of CBD in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and compare it to dexamethasone (DEX).

Methods

RAW264.7 macrophages in the logarithmic growth phase were incubated in the presence or absence of LPS. After that, the production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were measured. A luciferase reporter assay for nuclear factor kappa B (NF-κB) was performed, and the phosphorylation levels of the mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways were measured.

Results

The present study indicated that CBD had a similar anti-inflammatory effect to DEX by attenuating the LPS-induced production of NO, IL-6, and TNF-α. However, only CBD attenuated JNK phosphorylation levels, and only DEX attenuated IKK phosphorylation levels.

Conclusion

These results suggested that CBD and DEX exhibit similar anti-inflammatory effects on LPS-induced RAW264.7 macrophages mainly through suppressing the MAPK and NF-κB signaling pathways, but with different intracellular mechanisms. These findings suggested that CBD may be considered a natural anti-inflammatory agent for protecting skin from immune disorders.

Segregated functions of two cytosolic phospholipase A2 isoforms (cPLA2α and cPLA2ε) in lipid mediator generation

Among the phospholipase A₂ (PLA₂) superfamily, group IVA cytosolic PLA₂ (cPLA₂α) is currently attracting much attention as a central regulator of arachidonic acid (AA) metabolism linked to eicosanoid biosynthesis. Following cell activation, cPLA₂α selectively releases AA, a precursor of a variety of eicosanoids, from phospholipids in perinuclear membrane compartments. cPLA₂α-null mice display various phenotypes that could be largely explained by reduced eicosanoid signaling. In contrast, group IVE cPLA₂ε, another member of the cPLA₂ family, acts as a Ca²⁺-dependent N-acyltransferase rather than a PLA₂, thereby regulating the biosynthesis of N-acylethanolamines (NAEs), a unique class of lipid mediators with an anti-inflammatory effect. In response to Ca²⁺ signaling, cPLA₂ε translocates to phosphatidylserine-rich organelle membranes in the endocytic/recycling pathway. In vivo, cPLA₂ε is induced in keratinocytes of psoriatic skin, and its genetic deletion exacerbates psoriatic inflammation due to a marked reduction of NAE-related lipids. cPLA₂ε also contributes to NAE generation in several if not all mouse tissues. Thus, the two members of the cPLA₂ family, cPLA₂α and cPLA₂ε, catalyze distinct enzymatic reactions to mobilize distinct sets of lipid mediators, thereby differently regulating pathophysiological events in health and disease. Such segregation of the cPLA₂α-eicosanoid and cPLA₂ε-NAE pathways represents a new paradigm of research on PLA₂s and lipid mediators.

Distribution of Cannabinoid Receptors in Keratinocytes of Healthy Dogs and Dogs With Atopic Dermatitis

It is commonly accepted that some form of skin barrier dysfunction is present in canine atopic dermatitis (AD), one of the most common cutaneous pruritic inflammatory diseases of dogs. The impaired skin barrier function facilitates the penetration of allergens and subsequently stronger sensitization responses. The role of the endocannabinoid system (ECS) in the physiology and pathology of the skin is becoming increasingly established. It has been demonstrated that cannabinoid receptors are expressed in healthy and diseased skin and, based on current knowledge, it could be stated that cannabinoids are important mediators in the skin. The present study has been designed to immunohistochemically investigate the expression of the cannabinoid receptors type 1 (CB1R) and 2 (CB2R) and the cannabinoid-related receptors G protein-coupled receptor 55 (GPR55), transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1), peroxisome proliferator-activated receptors alpha (PPARα), and serotoninergic receptor 1a (5-HT1aR) in keratinocytes of healthy dogs and of dogs with AD. Samples of skin tissues were collected from 7 healthy controls (CTRL-dogs) and from 8 dogs with AD (AD-dogs). The tissue samples were processed using an immunofluorescence assay with commercially available antibodies, and the immunolabelling of the receptors studied was quantitatively evaluated. The keratinocytes of the CTRL- and the AD-dogs showed immunoreactivity for all the receptors investigated with a significant upregulation of CB2R, TRPA1, and 5-HT1aR in the epidermis of the AD-dogs. The presence of cannabinoid and cannabinoid-related receptors in healthy keratinocytes suggested the possible role of the ECS in canine epidermal homeostasis while their overexpression in the inflamed tissues of the AD-dogs suggested the involvement of the ECS in the pathogenesis of this disease, having a possible role in the related skin inflammation and itching. Based on the present findings, the ECS could be considered a potential therapeutic target for dogs with AD.

Cannabis sativa and Skin Health: Dissecting the Role of Phytocannabinoids

The use of Cannabis sativa is currently recognized to ease certain types of chronic pain, reduce chemotherapy-induced nausea, and improve anxiety. Nevertheless, few studies highlighted the therapeutic potential of C. sativa extracts and related phytocannabinoids for a variety of widespread skin disorders including acne, atopic dermatitis, psoriasis, pruritus, and pain. This review summarized the current evidence on the effects of phytocannabinoids at the cutaneous level through the collection of in vitro, in vivo, and clinical studies published on PubMed, Scopus, Embase, and Web of Science until October 2020. Phytocannabinoids have demonstrated potential anti-inflammatory, antioxidant, anti-aging, and anti-acne properties by various mechanisms involving either CB₁/₂-dependent and independent pathways. Not only classical immune cells, but also several skin-specific actors, such as keratinocytes, fibroblasts, melanocytes, and sebocytes, may represent a target for phytocannabinoids. Cannabidiol, the most investigated compound, revealed photoprotective, antioxidant, and anti-inflammatory mechanisms at the cutaneous level, while the possible impact on cell differentiation, especially in the case of psoriasis, would require further investigation. Animal models and pilot clinical studies supported the application of cannabidiol in inflammatory-based skin diseases. Also, one of the most promising applications of non-psychotropic phytocannabinoids is the treatment of seborrheic disorders, especially acne. In conclusion, the incomplete knowledge of the role of the endocannabinoid system in skin disorders emerged as an important limit for pharmacological investigations. Moreover, the limited studies conducted on C. sativa extracts suggested a higher potency than single phytocannabinoids, thus stimulating new research on phytocannabinoid interaction.

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.

Echinacea purpurea (L.) Moench: Biological and Pharmacological Properties. A Review

Echinacea purpurea (L.) Moench (EP)is a perennial herbaceous flowering plant, commonly known as purple coneflower and it belongs to the Asteraceae family. The Echinacea genus is originally from North America, in the United States, and its species are widely distributed throughout. There are nine different species of Echinacea, but only three of them are used as medicinal plants with wide therapeutic uses: Echinacea purpurea (L.) Moench, Echinacea pallida (Nutt.) Nutt. and Echinacea angustifolia DC. Several significant groups of bioactive compounds with pharmacological activities have been isolated from Echinacea species. Numerous beneficial effects have been demonstrated about these compounds. The immunomodulatory effect was initially demonstrated, but over time other effects have also been highlighted. The present review gives a comprehensive summary of the chemical constituents, bioactive compounds, biological effects and therapeutical uses of purple coneflower. Research shows that such a well-known and recognized species needs to be further studied to obtain efficient products with a guarantee of the safety.

Group IVE cytosolic phospholipase A2 limits psoriatic inflammation by mobilizing the anti-inflammatory lipid N-acylethanolamine

Psoriasis is an inflammatory disorder characterized by keratinocyte hyper-proliferation and Th17-type immune responses. However, the roles of bioactive lipids and the regulation of their biosynthesis in this chronic skin disease are not fully understood. Herein, we show that group IVE cytosolic phospholipase A₂ (cPLA₂ ε/PLA2G4E) plays a counterregulatory role against psoriatic inflammation by producing the anti-inflammatory lipid N-acylethanolamine (NAE). Lipidomics analysis of mouse skin revealed that NAE species and their precursors (N-acyl-phosphatidylethanolamine and glycerophospho-N-acylethanolamine) were robustly increased in parallel with the ongoing process of imiquimod (IMQ)-induced psoriasis, accompanied by a marked upregulation of cPLA₂ ε in epidermal keratinocytes. Genetic deletion of cPLA₂ ε exacerbated IMQ-induced ear swelling and psoriatic marker expression, with a dramatic reduction of NAE-related lipids in IMQ-treated, and even normal, skin. Stimulation of cultured human keratinocytes with psoriatic cytokines concomitantly increased PLA2G4E expression and NAE production, and supplementation with NAEs significantly attenuated the cytokine-induced upregulation of the psoriatic marker S100A9. Increased expression of cPLA₂ ε was also evident in the epidermis of psoriatic patients. These findings reveal for the first time the in vivo role of cPLA₂ ε, which is highly induced in the keratinocytes of the psoriatic skin, promotes the biosynthesis of NAE-related lipids, and contributes to limiting psoriatic inflammation.

Skin as an endocrine organ: A narrative review

Skin being the largest organ of the body, is equipped with numerous functional properties. Over the past few years, intricate research into the biology of skin has led to a gamut of discoveries. Skin is now regarded as one of the most vital endocrine organs. The skin contains equivalents of the hypothalamo-pituitary-adrenal axis, hypothalamo-pituitary-thyroid axis and the appendages produce multiple hormones such as Vitamin D, sex steroids, retinoids and opioids. In this article, we will explore the role of skin as a target and source of some of the hormones of the human body, and briefly touch on the clinical applications.

The Transdermal Delivery of Therapeutic Cannabinoids

Recently, several studies have indicated an increased interest in the scientific community regarding the application of Cannabis sativa plants, and their extracts, for medicinal purposes. This plant of enormous medicinal potential has been legalised in an increasing number of countries globally. Due to the recent changes in therapeutic and recreational legislation, cannabis and cannabinoids are now frequently permitted for use in clinical settings. However, with their highly lipophilic features and very low aqueous solubility, cannabinoids are prone to degradation, specifically in solution, as they are light-, temperature-, and auto-oxidation-sensitive. Thus, plant-derived cannabinoids have been developed for oral, nasal-inhalation, intranasal, mucosal (sublingual and buccal), transcutaneous (transdermal), local (topical), and parenteral deliveries. Among these administrations routes, topical and transdermal products usually have a higher bioavailability rate with a prolonged steady-state plasma concentration. Additionally, these administrations have the potential to eliminate the psychotropic impacts of the drug by its diffusion into a nonreactive, dead stratum corneum. This modality avoids oral administration and, thus, the first-pass metabolism, leading to constant cannabinoid plasma levels. This review article investigates the practicality of delivering therapeutic cannabinoids via skin in accordance with existing literature.

Cannabis-Based Products for the Treatment of Skin Inflammatory Diseases: A Timely Review

The use of natural products in dermatology is increasingly being pursued due to sustainability and ecological issues, and as a possible way to improve the therapeutic outcome of chronic skin diseases, relieving the burden for both patients and healthcare systems. The legalization of cannabis by a growing number of countries has opened the way for researching the use of cannabinoids in therapeutic topical formulations. Cannabinoids are a diverse class of pharmacologically active compounds produced by Cannabis sativa (phytocannabinoids) and similar molecules (endocannabinoids, synthetic cannabinoids). Humans possess an endocannabinoid system involved in the regulation of several physiological processes, which includes naturally-produced endocannabinoids, and proteins involved in their transport, synthesis and degradation. The modulation of the endocannabinoid system is a promising therapeutic target for multiple diseases, including vascular, mental and neurodegenerative disorders. However, due to the complex nature of this system and its crosstalk with other biological systems, the development of novel target drugs is an ongoing challenging task. The discovery of a skin endocannabinoid system and its role in maintaining skin homeostasis, alongside the anti-inflammatory actions of cannabinoids, has raised interest in their use for the treatment of skin inflammatory diseases, which is the focus of this review. Oral treatments are only effective at high doses, having considerable adverse effects; thus, research into plant-based or synthetic cannabinoids that can be incorporated into high-quality, safe topical products for the treatment of inflammatory skin conditions is timely. Previous studies revealed that such products are usually well tolerated and showed promising results for example in the treatment of atopic dermatitis, psoriasis, and contact dermatitis. However, further controlled human clinical trials are needed to fully unravel the potential of these compounds, and the possible side effects associated with their topical use.

In vitro percutaneous absorption studies of cannabidiol using human skin: Exploring the effect of drug concentration, chemical enhancers, and essential oils

Cannabidiol, a non-psychoactive constituent of cannabis, has garnered much attention after United States Food and Drug Administration approved Epidiolex® for oral use. Although therapeutic effect of cannabidiol after systemic absorption has been investigated extensively, its therapeutic potential in treating skin disorders after local delivery still needs further exploration. Our study has investigated the effect of cannabidiol concentration, chemical enhancers, and essential oils on percutaneous absorption of cannabidiol. In vitro permeation tests were conducted on human skin. The 24 h study results suggest no significant difference in amount of drug absorbed into skin, between 5% (242.41 ± 12.17 µg/cm²) and 10% (232.79 ± 20.82 cm²) cannabidiol solutions. However, 1% delivered (23.02 ± 4.74 µg/cm²) significantly lower amount of drug into skin than 5% and 10%. Transcutol and isopropyl myristate did not enhance delivery of cannabidiol. However, oleic acid was found to be useful as chemical enhancer. Oleic acid (43.07 ± 10.11 µg/cm²) had significantly higher cannabidiol delivery into skin than the group without oleic acid (10.98 ± 3.40 µg/cm²) after a 4 h in vitro permeation study. Essential oils at concentrations tested had lower total cannabidiol delivery when compared to control. This study's findings will help guide future research on the pharmacological effect of percutaneously delivered cannabidiol on inflammatory skin disorders.

Evaluations of Skin Permeability of Cannabidiol and Its Topical Formulations by Skin Membrane-Based Parallel Artificial Membrane Permeability Assay and Franz Cell Diffusion Assay

INTRODUCTION

Cannabinoids including cannabidiol (CBD) have attracted enormous interest as bioactive ingredients for various dermatological and/or cosmeceutical uses. However, topical applications of cannabinoids might be limited without a fundamental understanding of their skin permeability. Herein, we aimed to evaluate the skin permeability of CBD and its topical formulations using artificial skin membrane assays. The solubility and stability of CBD in various surfactants that are commonly used in topical applications were also evaluated.

METHODS

CBD and two CBD-incorporated topical formulations (cream and gel) were prepared for this study. Computational predictions (SwissADME and DERMWIN™) and the parallel artificial membrane permeability assay (PAMPA) were used to evaluate the skin permeability of CBD isolate. The Franz cell diffusion (in vitro release testing) assay was used to evaluate the skin permeability of CBD formulations. The solubility and stability of CBD in surfactants were assessed by high-performance liquid chromatography and mass spectrometry analysis.

RESULTS

CBD isolate showed favorable skin permeability in the SwissADME and DERMWIN™ predictions (-Log Kp of 3.6 and 5.7 cm/s, respectively) and PAMPA (-LogPe value of 5.0 at pH of 6.5 and 7.4). In addition, CBD had higher solubility (378.4 μg/mL) in surfactant Tween 20 as compared to its solubility in polyisobutene. In an acidic environment (pH 5 and 6), Tween 20 maintained the CBD content at 81% and 70% over 30 days, respectively. CBD in the formulations of cream and gel also had moderate skin permeability in the Franz cell diffusion assay.

CONCLUSION

Data from artificial membrane-based assays support that CBD is a skin permeable cannabinoid and the permeability and stability of its formulations may be influenced by several factors such as surfactant and pH environment. Findings from our study suggest that CBD may have suitable skin permeability for the development of dermatological and/or cosmeceutical applications but further studies using in vivo models are warranted to confirm this.

Cannabis and the skin

The public and health care providers are increasingly curious about the potential medical benefits of Cannabis. In vitro and in vivo studies of Cannabis have suggested it has favorable effects on regulating pain, pruritus, and inflammation, making it a potentially attractive therapeutic agent for many dermatologic conditions. The body of literature reporting on the role of cannabinoids in dermatology is in its infancy but growing. We review the current research, possible cutaneous adverse effects, and future directions for cannabinoids and their use in skin cancer, acne, psoriasis, pruritus, dermatitis, scleroderma, dermatomyositis, cutaneous lupus erythematous, epidermolysis bullosa, pain, and wound healing.

Analytical approaches to assess metabolic changes in psoriasis

Psoriasis is one of the most common human skin diseases, although its development is not limited to one tissue, but is associated with autoimmune reactions throughout the body. Overproduction of pro-inflammatory cytokines and growth factors systemically stimulates the proliferation of skin cells, which manifests as excessive exfoliation of the epidermis, and/or arthritis, as well as other comorbidities such as insulin resistance, metabolic syndrome, hypertension, and depression. Thus, there is a great need for a thorough analysis of the pathophysiology of psoriatic patients, including classical methods, such as spectrophotometry, chromatography, or Western blot, and also novel omics approaches such as lipidomics and proteomics. Moreover, the extensive pathophysiology forces increased research examining biological changes in both skin cells, and systemically. A wide range of techniques involved in lipidomic research based on a combination of mass spectrometry and different types of chromatography (RP-LC-QTOF-MS/MS, HILIC-QTOF-MS/MS or RP-LC-QTRAP-MS/MS), have allowed comprehensive assessment of lipid modification in psoriatic skin and provided new insight into the role of lipids and their mechanism of action in psoriasis. Moreover, proteomic analysis using gel-nanoLC-OrbiTrap-MS/MS, as well as MALDI-TOF/TOF techniques facilitates the description of panels of enzymes involved in lipidome modifications, and the response of the endocannabinoid system to metabolic changes. Psoriasis is known to alter the expression of proteins that are involved in the inflammatory and antioxidant response, as well as protein biosynthesis, degradation, as well as cell proliferation and apoptosis. Knowledge of changes in the lipidomic and proteomic profile will not only allow the understanding of psoriasis pathophysiology, but also facilitate proper and early diagnosis and effective pharmacotherapy.

Diabetes and Cannabinoid CB1 receptor deficiency promote similar early onset aging-like changes in the skin

BACKGROUND

The cannabinoid receptor type-1 (CB₁R) is a major regulator of metabolism, growth and inflammation. Yet, its potential role in the skin is not well understood. Our aim was to evaluate the role of CB₁R in aging-like diabetic skin changes by using a CB₁R knockout mouse model.

METHODS

We evaluated several signals of skin aging in wild-type control (WT), WT streptozotocin-induced type 1 diabetic mice (WT DM), CB₁R knockout (CB₁RKO) and CB₁RKO DM mice. We quantified markers of inflammation, angiogenesis, antioxidant enzymes and collagen content. Moreover, we evaluate reactive oxygen species (ROS) levels and macrophage phenotype, M1 and M2.

RESULTS

CB₁R expression is decreased in the skin of WT DM mice and collagen levels are decreased in the skin of WT DM, CB₁RKO and CB₁RKO DM mice. Additionally, the absence of CB₁R correlated with higher expression of pro-inflammatory markers, also evident in WT DM or CB₁RKO DM mice. Moreover, the M1/M2 macrophage ratio and ROS levels were significantly elevated but in the diabetic WT and the CB₁RKO mice, consistent with a significant decrease in the antioxidant capacity of the skin.

CONCLUSIONS

Our results indicate that CB₁R deficiency in the skin may lead to accelerated skin aging due to the increased production of ROS, a decrease in the antioxidant defenses and a higher pro-inflammatory environment. A significant decrease in the CB₁R expression may be a significant contributing factor to the early aging-like changes in diabetes.

Multi-omics analysis to decipher the molecular link between chronic exposure to pollution and human skin dysfunction

Environmental pollution is composed of several factors, namely particulate matter (PM2.5, PM10), ozone and Ultra Violet (UV) rays among others and first and the most exposed tissue to these substances is the skin epidermis. It has been established that several skin disorders such as eczema, acne, lentigines and wrinkles are aggravated by exposure to atmospheric pollution. While pollutants can interact with skin surface, contamination of deep skin by ultrafine particles or Polycyclic aromatic hydrocarbons (PAH) might be explained by their presence in blood and hair cortex. Molecular mechanisms leading to skin dysfunction due to pollution exposure have been poorly explored in humans. In addition to various host skin components, cutaneous microbiome is another target of these environment aggressors and can actively contribute to visible clinical manifestation such as wrinkles and aging. The present study aimed to investigate the association between pollution exposure, skin microbiota, metabolites and skin clinical signs in women from two cities with different pollution levels. Untargeted metabolomics and targeted proteins were analyzed from D-Squame samples from healthy women (n = 67 per city), aged 25-45 years and living for at least 15 years in the Chinese cities of Baoding (used as a model of polluted area) and Dalian (control area with lower level of pollution). Additional samples by swabs were collected from the cheeks from the same population and microbiome was analysed using bacterial 16S rRNA as well as fungal ITS1 amplicon sequencing and metagenomics analysis. The level of exposure to pollution was assessed individually by the analysis of polycyclic aromatic hydrocarbons (PAH) and their metabolites in hair samples collected from each participant. All the participants of the study were assessed for the skin clinical parameters (acne, wrinkles, pigmented spots etc.). Women from the two cities (polluted and less polluted) showed distinct metabolic profiles and alterations in skin microbiome. Profiling data from 350 identified metabolites, 143 microbes and 39 PAH served to characterize biochemical events that correlate with pollution exposure. Finally, using multiblock data analysis methods, we obtained a potential molecular map consisting of multi-omics signatures that correlated with the presence of skin pigmentation dysfunction in individuals living in a polluted environment. Overall, these signatures point towards macromolecular alterations by pollution that could manifest as clinical sign of early skin pigmentation and/or other imperfections.

Topical Use of Cannabis sativa L. Biochemicals

Cannabis sativa L. plant is currently attracting increasing interest in cosmetics and dermatology. In this review, the biologically active compounds of hemp are discussed. Particularly the complex interactions of cannabinoids with the endocannabinoid system of the skin to treat various conditions (such as acne, allergic contact dermatitis, melanoma, and psoriasis) with clinical data. Moreover, the properties of some cannabinoids make them candidates as cosmetic actives for certain skin types. Hemp seed oil and its minor bioactive compounds such as terpenes, flavonoids, carotenoids, and phytosterols are also discussed for their added value in cosmetic formulation.

Cannabinoid use and effects in patients with epidermolysis bullosa: an international cross-sectional survey study

BACKGROUND

Epidermolysis bullosa (EB) patient anecdotes and case reports indicate that cannabinoid-based medicines (CBMs) may alleviate pain and pruritus and improve wound healing. CBM use has not been characterized in the EB patient population.

OBJECTIVES

To evaluate CBM use among EB patients, including CBM types, effects on symptoms (e.g., pain and pruritus), disease process (e.g., blistering, wounds, and inflammation), well-being (e.g., sleep, appetite) and concomitant medications.

METHODS

English-speaking EB patients or caregivers completed an online international, anonymous, cross-sectional survey regarding CBM use. Respondents reported the types of CBMs, subsequent effects including perceived EB symptom alteration, changes in medication use, and side effects.

RESULTS

Seventy-one EB patients from five continents reported using or having used CBMs to treat their EB. Missing question responses ranged between 0 (0%) and 33 (46%). Most used more than one CBM preparation (mean: 2.4 ± 1.5) and route of administration (mean: 2.1 ± 1.1). Topical and ingested were the most common routes. Pain and pruritus were reported retrospectively to decrease by 3 points (scale: 0-10; p < 0.001 for both) after CBM use. Most reported that CBM use improved their overall EB symptoms (95%), pain (94%), pruritus (91%) and wound healing (81%). Most participants (79%) reported decreased use of pain medications. The most common side-effect was dry mouth (44%).

CONCLUSIONS

CBMs improve the perception of pain, pruritus, wound healing, and well-being in EB patients and reduced concomitant medication use. Nevertheless, a direct relation between the use of CBMs and reduction of the above-mentioned symptoms cannot be proven by these data. Therefore, future controlled studies using pharmaceutically standardised CBM preparations in EB are warranted to delineate the risks and benefits of CBMs.

The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems. In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development. The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development. The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases. This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as "C. sativa L." or "medical cannabis"), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.

Cannabinoids Drugs and Oral Health-From Recreational Side-Effects to Medicinal Purposes: A Systematic Review

Background: marijuana, the common name for cannabis sativa preparations, is one of the most consumed drug all over the world, both at therapeutical and recreational levels. With the legalization of medical uses of cannabis in many countries, and even its recreational use in most of these, the prevalence of marijuana use has markedly risen over the last decade. At the same time, there is also a higher prevalence in the health concerns related to cannabis use and abuse. Thus, it is mandatory for oral healthcare operators to know and deal with the consequences and effects of cannabis use on oral cavity health. This review will briefly summarize the components of cannabis and the endocannabinoid system, as well as the cellular and molecular mechanisms of biological cannabis action in human cells and biologic activities on tissues. We will also look into oropharyngeal tissue expression of cannabinoid receptors, together with a putative association of cannabis to several oral diseases. Therefore, this review will elaborate the basic biology and physiology of cannabinoids in human oral tissues with the aim of providing a better comprehension of the effects of its use and abuse on oral health, in order to include cannabinoid usage into dental patient health records as well as good medicinal practice. Methods: the paper selection was performed by PubMed/Medline and EMBASE electronic databases, and reported according to the PRISMA guidelines. The scientific products were included for qualitative analysis. Results: the paper search screened a total of 276 papers. After the initial screening and the eligibility assessment, a total of 32 articles were considered for the qualitative analysis. Conclusions: today, cannabis consumption has been correlated to a higher risk of gingival and periodontal disease, oral infection and cancer of the oral cavity, while the physico-chemical activity has not been completely clarified. Further investigations are necessary to evaluate a therapeutic efficacy of this class of drugs for the promising treatment of several different diseases of the salivary glands and oral diseases.

CBD Promotes Oral Ulcer Healing via Inhibiting CMPK2-Mediated Inflammasome

Oral ulcer is a common oral inflammatory lesion accompanied by severe pain but with few effective treatments. Cannabidiol (CBD) is recently emerging for its therapeutic potential in a range of diseases, including inflammatory conditions and cancers. Here we show that CBD oral spray on acid- or trauma-induced oral ulcers on mice tongue inhibits inflammation, relieves pain, and accelerates lesion closure. Notably, the enrichment of genes associated with the NOD, LRR, and NLRP3 pyrin domain-containing protein 3 (NLRP3) inflammasome pathway is downregulated after CBD treatment. The expression of cleaved-gasdermin D (GSDMD) and the percentage of pyroptotic cells are reduced as well. In addition, CBD decreases the expression of cytidine/uridine monophosphate kinase 2 (CMPK2), which subsequently inhibits the generation of oxidized mitochondria DNA and suppresses inflammasome activation. These immunomodulating effects of CBD are mostly blocked by peroxisome proliferator activated receptor γ (PPARγ) antagonist and partially antagonized by CB₁ receptor antagonist. Our results demonstrate that CBD accelerates oral ulcer healing by inhibiting CMPK2-mediated NLRP3 inflammasome activation and pyroptosis, which are mediated mostly by PPARγ in the nucleus and partially by CB₁ in the plasma membrane.

Targeting cannabinoid receptor 2 (CB2) limits collagen production-An in vitro study in a primary culture of human fibroblasts

Previous studies showed that cannabinoid 2 (CB2) receptor is involved in skin inflammation, fibrogenesis and re-epithelialization in mice, indicating that this receptor may be implicated in wound healing. Thus, topical use of cannabinoids may have a role in local fibrotic and wound healing diseases such as scars or keloids. We investigate the effect of the CB2 selective receptor agonist (6aR,10aR)-3-(1,1-Dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran (JWH133) and the CB2 selective receptor antagonist (6-Iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl)(4-methoxyphenyl)-methanone (AM630), on primary cultures of human fibroblasts. Primary cultures of adult human fibroblasts were obtained from abdominal human skin samples. Fibroblasts pretreated with JWH133 and/or AM630 were stimulated with TGF-β (10 ng/ml). Fibroblast activation into myofibroblasts was quantified by the expression of alpha-smooth muscle actin (α-SMA) using Immunocytochemistry and Western Blot assays. Collagen content was quantified with the Sirius red staining assay. Upon human fibroblasts stimulation with TGF-β, a significant increase on α-SMA and CB2 receptor expression was observed. In these cells, JWH133 decreased α-SMA expression and collagen content. However, this effect was not observed in resting human fibroblasts. AM630 decreased α-SMA expression and collagen content in both resting and activated fibroblasts. This effect was time- and concentration-dependent with an IC₅₀ value of 11 μM. The CB2 receptor appears to be involved in fibroblast repair during skin wound healing in humans, as TGF-β increases CB2 receptor expression and JWH133 produces an anti-fibrotic effect in human fibroblasts. AM630 also showed an anti-fibrotic effect hypothesizing that other cannabinoid receptors, such as TRPV, may be involved in this response.

The significance of CYP11A1 expression in skin physiology and pathology

CYP11A1, a member of the cytochrome P450 family, plays several key roles in the human body. It catalyzes the first and rate-limiting step in steroidogenesis, converting cholesterol to pregnenolone. Aside from the classical steroidogenic tissues such as the adrenals, gonads and placenta, CYP11A1 has also been found in the brain, gastrointestinal tract, immune systems, and finally the skin. CYP11A1 activity in the skin is regulated predominately by StAR protein and hence cholesterol levels in the mitochondria. However, UVB, UVC, CRH, ACTH, cAMP, and cytokines IL-1, IL-6 and TNFα can also regulate its expression and activity. Indeed, CYP11A1 plays several critical roles in the skin through its initiation of local steroidogenesis and specific metabolism of vitamin D, lumisterol, and 7-dehydrocholesterol. Products of these pathways regulate the protective barrier and skin immune functions in a context-dependent fashion through interactions with a number of receptors. Disturbances in CYP11A1 activity can lead to skin pathology.

Topical and nutricosmetic products for healthy hair and dermal antiaging using "dual-acting" (2 for 1) plant-based peptides, hormones, and cannabinoids

One of the side effects of oral antiaging retinoids is increased hair shedding. Retinoids promote the expression of TGF-β2 from fibroblasts, which stimulate collagen expression but silences keratinocytes. Since keratinocytes normally influence differentiation of dermal papilla cells at the base of the hair follicle, retinoids feasibly inhibit hair growth via the increased expression of TGF-β2, which inhibits Wnt/β-catenin signaling. Fortunately, the plant kingdom provides an array of alternatives as dual-acting nutricosmetics and topicals that work independently of TGF-β2 to confer dermal antiaging and hair health effects. These alternatives include "plant hormones" such as cytokinins and phytoestrogens. Many cytokinins are agonists of the G-coupled adenosine receptors. Partial agonism of adenosine receptors promotes collagen synthesis independently of TGF-β2 signaling. Adenosine expression is potentially also the mechanism of minoxidil in promotion of scalp hair growth. Because of crosstalk between adenosine and cannabinoid receptors it makes sense to try combinations of specific CB2 agonists and cytokinins (or phytoestrogens). However, dual-acting cosmetics including peptides with high numbers of positively charged amino acids, such as lysine or arginine, offer real potential as they can be processed from multiple botanical candidates, including almond, fenugreek, pea sprouts, soy, and seaweeds. The current review summarizes much of what is known about retinoid alternatives in the plant kingdom and identifies potentially fruitful new areas of research.

Topical cannabis-based medicines - A novel adjuvant treatment for venous leg ulcers: An open-label trial

Venous leg ulcers are highly prevalent lower limb integumentary wounds that remain challenging to heal despite the use of evidence-based compression therapies. A multitude of adjuvant treatments has been studied but none have demonstrated enough efficacy to gain adoption into treatment guidelines. Global attention on Cannabis-Based Therapies is increasing and has been driven by quantum scientific advancements in the understanding of the endocannabinoid signalling system. Topical Cannabis-Based Medicines represent a novel treatment paradigm for venous leg ulcers in terms of promoting wound closure. Fourteen complex patients with sixteen recalcitrant leg ulcers were treated with Topical Cannabis-Based Medicines in conjunction with compression bandaging, every second day, to both wound bed and peri-wound tissues. The cohort had a mean age of 75.8 years and was medically complex as reflected by a mean M3 multimorbidity index score of 2.94 and a mean Palliative Performance Scale score of 67.1%. Complete wound closure, defined as being fully epithelialized, was achieved among 11 patients (79%) and 13 wounds (81%) within a median of 34 days. All three remaining patients demonstrated progressive healing trends but were lost to follow-up. The treatments were well tolerated, and no significant adverse reactions were experienced. The rapid wound closure of previously non-healing venous leg ulcers among elderly and highly complex patients suggests that Topical Cannabis-Based Medicines may become effective adjuvants in conjunction with compression therapy. This may also indicate that they may have an even broader role within integumentary and wound management. Therefore, this treatment paradigm warrants being subjected to controlled trials.

Cannabinoids and Inflammations of the Gut-Lung-Skin Barrier

Recent studies have identified great similarities and interferences between the epithelial layers of the digestive tract, the airways and the cutaneous layer. The relationship between these structures seems to implicate signaling pathways, cellular components and metabolic features, and has led to the definition of a gut-lung-skin barrier. Inflammation seems to involve common features in these tissues; therefore, analyzing the similarities and differences in the modulation of its biomarkers can yield significant data promoting a better understanding of the particularities of specific signaling pathways and cellular effects. Cannabinoids are well known for a wide array of beneficial effects, including anti-inflammatory properties. This paper aims to explore the effects of natural and synthetic cannabinoids, including the components of the endocannabinoid system, in relation to the inflammation of the gut-lung-skin barrier epithelia. Recent advancements in the use of cannabinoids as anti-inflammatory substances in various disorders of the gut, lungs and skin are detailed. Some studies have reported mixed or controversial results, and these have also been addressed in our paper.

Delivering therapeutic cannabinoids via skin: Current state and future perspectives

Adequate evidence exists in the literature indicating a relatively positive shift with regards to the legal acceptance of cannabis and cannabis-derived products for medicinal purposes in some countries. Concomitantly, scientists are showing renewed interest in cannabis-related research work. Over the years, clinical and preclinical studies have demonstrated the therapeutic significance of cannabinoids for diverse indications. Additionally, efforts are being made to develop cannabis-related products into acceptable prescription products. FDA authorization for the commercial use of four cannabinoid-derived products, available as oral dosage forms is a significant progress already. However, there are certain drawbacks associated with the conventional delivery forms of cannabinoids. These include low oral bioavailability due to hepatic degradation, gastric instability, poor water solubility, and the side effects experienced upon the use of high doses of psychotropic cannabinoids associated with heightened plasma concentrations of the drug. These are however, limitable with the aid of transcutaneous drug delivery. Emerging topical and transdermal strategies could be exploited for the successful development of highly effective delivery systems for cannabinoids. This review discusses the feasibility of delivering therapeutic cannabinoids via skin and provides a comprehensive account of the supporting research studies that have been reported in the literature till date.