Cannabidiol modulation of immune cell function: in vitro insights and therapeutic implications for atopic dermatitis

Abstract

Introduction: Cannabidiol (CBD) exhibits neuroprotective, anti-inflammatory, and immunomodulatory properties, making it a promising candidate for addressing inflammatory skin disorders like atopic dermatitis.

Aim: This study aimed to (i) investigate CBD's impact on lymphocyte proliferation and lymphocyte viability; (ii) assess in vitro cytotoxicity U937 cells (a human promonocytic cell line) of CBD/cytotoxicity of CBD on U937 cells; (iii) provide insights into CBD immunomodulatory potential, and (iv) evaluate suitability of CBD for treating inflammatory skin conditions.

Material and methods: To this aim PBMCs from healthy donors were cultured with mitogen and two different CBD doses (0.1 and 1 mg/ml), assessing B and T cell proliferation through flow cytometry. CBD inhibited mitogen-induced lymphocyte proliferation, reducing the percentage of proliferating T and B cells. Notably, both CBD doses did not exhibit cytotoxicity on lymphocytes as revealed by viability assessment. We also analysed the effect of CBD on U937 cells using an optical microscopy approach. Interestingly, the higher dose of CBD exerted a cytotoxic effect on U937 cells, while the lower dose was well tolerated.

Results: We analysed the effect of an adjuvant treatment for atopic dermatitis with a CBD-containing cleansing cream in reducing itch. Notably, the treatment with the CBD-containing cleansing cream significantly reduced itch in patients suffering from atopic dermatitis.

Conclusions: These findings affirm CBD's immunomodulatory characteristics, emphasizing its potential therapeutic application in inflammatory skin disorders.

Keywords: atopic dermatitis; cannabidiol; cannabinoid; cytotoxicity; lymphocyte; proliferation.

Figure 1

Freshly isolated PBMCs were stained with CFSE and cultured with PHA alone or in combination with CBD, tested at 2 different doses. Untreated cultures and cells treated with CBD alone were used as controls. After culture, cells were harvested and stained with anti-CD3 and anti-CD19 antibodies and analysed by flow cytometry. After gating on total lymphocytes, B and T cells were selected (A), and the percentage of proliferating T cells and B cells (B) were then measured for each condition. Representative dot plots of proliferating T cells from one donor are shown (A). The stacked overlays of CFSE expression in T cells (left panel) and B cells (right panel) for all conditions are shown for one donor (B). Proliferation rates of T (light grey) and B (dark grey) cells are presented as mean ± SD (C). The graph illustrates the fold change of T and B cell proliferation rate in (CBD + PHA) with respect to PHA alone (D). Cell viability assessment as revealed by trypan blue exclusion (E)

Figure 2

U 937 cells (promonocytic cell line) were cultured alone or with increasing doses of CBD for 48 h, harvested, spun on microscope slides, and stained with the May-Grunwald and Giemsa method (A). Untreated cells, cells (CTRL)/control cells or those treated with 0.1 and 1 mg/ml CBD (from the upper left panel, clockwise). Methodology used for the quantification of damaged cells (B). Quantification of damaged cells (C). Clinical efficacy of the CBD-containing preparation (cleansing cream) was observed, with a statistically significant decrease noted in the CBD-treated group compared to the control group over a 5-week period (D)