Restorative Effect of Microalgae Nannochloropsis oceanica Lipid Extract on Phospholipid Metabolism in Keratinocytes Exposed to UVB Radiation.

Ultraviolet B (UVB) radiation induces oxidative stress in skin cells, generating reactive oxygen species (ROS) and perturbing enzyme-mediated metabolism. This disruption is evidenced with elevated concentrations of metabolites that play important roles in the modulation of redox homeostasis and inflammatory responses. Thus, this research sought to determine the impacts of the lipid extract derived from the Nannochloropsis oceanica microalgae on phospholipid metabolic processes in keratinocytes subjected to UVB exposure. UVB-irradiated keratinocytes were treated with the microalgae extract. Subsequently, analyses were performed on cell lysates to ascertain the levels of phospholipid/free fatty acids (GC-FID), lipid peroxidation byproducts (GC-MS), and endocannabinoids/eicosanoids (LC-MS), as well as to measure the enzymatic activities linked with phospholipid metabolism, receptor expression, and total antioxidant status (spectrophotometric methods). The extract from N. oceanica microalgae, by diminishing the activities of enzymes involved in the synthesis of endocannabinoids and eicosanoids (PLA2/COX1/2/LOX), augmented the concentrations of anti-inflammatory and antioxidant polyunsaturated fatty acids (PUFAs), namely DHA and EPA. These concentrations are typically diminished due to UVB irradiation. As a consequence, there was a marked reduction in the levels of pro-inflammatory arachidonic acid (AA) and associated pro-inflammatory eicosanoids and endocannabinoids, as well as the expression of CB1/TRPV1 receptors. The microalgal extract also mitigated the increase in lipid peroxidation byproducts, specifically MDA in non-irradiated samples and 10-F4t-NeuroP in both control and post-UVB exposure. These findings indicate that the lipid extract derived from N. oceanica, by mitigating the deleterious impacts of UVB radiation on keratinocyte phospholipids, assumed a pivotal role in reinstating intracellular metabolic equilibrium.

Preliminary Comparison of Molecular Antioxidant and Inflammatory Mechanisms Determined in the Peripheral Blood Granulocytes of COVID-19 Patients.

The aim of this study was to evaluate selected parameters of redox signaling and inflammation in the granulocytes of COVID-19 patients who recovered and those who died. Upon admission, the patients did not differ in terms of any relevant clinical parameter apart from the percentage of granulocytes, which was 6% higher on average in those patients who died. Granulocytes were isolated from the blood of 15 healthy people and survivors and 15 patients who died within a week, and who were selected post hoc for analysis according to their matching gender and age. They differed only in the lethal outcome, which could not be predicted upon arrival at the hospital. The proteins level (respective ELISA), antioxidant activity (spectrophotometry), and lipid mediators (UPUPLC-MS) were measured in the peripheral blood granulocytes obtained via gradient centrifugation. The levels of Nrf2, HO-1, NFκB, and IL-6 were higher in the granulocytes of COVID-19 patients who died within a week, while the activity of cytoplasmic Cu,Zn-SOD and mitochondrial Mn-SOD and IL-2/IL-10 were lower in comparison to the levels observed in survivors. Furthermore, in the granulocytes of those patients who died, an increase in pro-inflammatory eicosanoids (PGE2 and TXB2), together with elevated cannabinoid receptors 1 and 2 (associated with a decrease in the anti-inflammatory 15d-PGJ2), were found. Hence, this study suggests that by triggering transcription factors, granulocytes activate inflammatory and redox signaling, leading to the production of pro-inflammatory eicosanoids while reducing cellular antioxidant capacity through SOD, thus expressing an altered response to COVID-19, which may result in the onset of systemic oxidative stress, ARDS, and the death of the patient.

Diversified Effects of COVID-19 as a Consequence of the Differential Metabolism of Phospholipids and Lipid Peroxidation Evaluated in the Plasma of Survivors and Deceased Patients upon Admission to the Hospital.

As a result of SARS-CoV-2 infection, inflammation develops, which promotes oxidative stress, leading to modification of phospholipid metabolism. Therefore, the aim of this study is to compare the effects of COVID-19 on the levels of phospholipid and free polyunsaturated fatty acids (PUFAs) and their metabolites produced in response to reactions with reactive oxygen species (ROS) and enzymes (cyclooxygenases-(COXs) and lipoxygenase-(LOX)) in the plasma of patients who either recovered or passed away within a week of hospitalization. In the plasma of COVID-19 patients, especially of the survivors, the actions of ROS and phospholipase A2 (PLA2) cause a decrease in phospholipid fatty acids level and an increase in free fatty acids (especially arachidonic acid) despite increased COXs and LOX activity. This is accompanied by an increased level in lipid peroxidation products (malondialdehyde and 8-isoprostaglandin F2α) and lipid mediators generated by enzymes. There is also an increase in eicosanoids, both pro-inflammatory as follows: thromboxane B2 and prostaglandin E2, and anti-inflammatory as follows: 15-deoxy-Δ-12,14-prostaglandin J2 and 12-hydroxyeicosatetraenoic acid, as well as endocannabinoids (anandamide-(AEA) and 2-arachidonylglycerol-(2-AG)) observed in the plasma of patients who recovered. Moreover, the expression of tumor necrosis factor α and interleukins (IL-6 and IL-10) is increased in patients who recovered. However, in the group of patients who died, elevated levels of N-oleoylethanolamine and N-palmitoylethanolamine are found. Since lipid mediators may have different functions depending on the onset of pathophysiological processes, a stronger pro-inflammatory response in patients who have recovered may be the result of the defensive response to SARS-CoV-2 in survivors associated with specific changes in the phospholipid metabolism, which could also be considered a prognostic factor.

Beneficial Changes in Rat Vascular Endocannabinoid System in Primary Hypertension and under Treatment with Chronic Inhibition of Fatty Acid Amide Hydrolase by URB597.

Our study aimed to examine the effects of hypertension and the chronic administration of the fatty acid amide hydrolase (FAAH) inhibitor URB597 on vascular function and the endocannabinoid system in spontaneously hypertensive rats (SHR). Functional studies were performed on small mesenteric G3 arteries (sMA) and aortas isolated from SHR and normotensive Wistar Kyoto rats (WKY) treated with URB597 (1 mg/kg; twice daily for 14 days). In the aortas and sMA of SHR, endocannabinoid levels and cannabinoid CB1 receptor (CB1R) expression were elevated. The CB1R antagonist AM251 diminished the methanandamide-evoked relaxation only in the sMA of SHR and enhanced the vasoconstriction induced by phenylephrine and the thromboxane analog U46619 in sMA in SHR and WKY. In the sMA of SHR, URB597 elevated anandamide levels, improved the endothelium-dependent vasorelaxation to acetylcholine, and in the presence of AM251 reduced the vasoconstriction to phenylephrine and enhanced the vasodilatation to methanandamide, and tended to reduce hypertrophy. In the aortas, URB597 elevated endocannabinoid levels improved the endothelium-dependent vasorelaxation to acetylcholine and decreased CB1R expression. Our study showed that hypertension and chronic administration of URB597 caused local, resistance artery-specific beneficial alterations in the vascular endocannabinoid system, which may bring further advantages for therapeutic application of pharmacological inhibition of FAAH.

Cannabidiol Ameliorates Monocrotaline-Induced Pulmonary Hypertension in Rats.

Cannabidiol (CBD) is known for its vasorelaxant (including in the human pulmonary artery), anti-proliferative and anti-inflammatory properties. The aim of our study was to examine the potential preventive effect of chronic CBD administration (10 mg/kg/day for three weeks) on monocrotaline (MCT)-induced pulmonary hypertension (PH) rats. PH was connected with elevation of right ventricular systolic pressure; right ventricle hypertrophy; lung edema; pulmonary artery remodeling; enhancement of the vasoconstrictor and decreasing vasodilatory responses; increases in plasma concentrations of tissue plasminogen activator, plasminogen activator inhibitor type 1 and leukocyte count; and a decrease in blood oxygen saturation. CBD improved all abovementioned changes induced by PH except right ventricle hypertrophy and lung edema. In addition, CBD increased lung levels of some endocannabinoids (anandamide, N-arachidonoyl glycine, linolenoyl ethanolamide, palmitoleoyl ethanolamide and eicosapentaenoyl ethanolamide but not 2-arachidonoylglycerol). CBD did not affect the cardiopulmonary system of control rats or other parameters of blood morphology in PH. Our data suggest that CBD ameliorates MCT-induced PH in rats by improving endothelial efficiency and function, normalization of hemostatic alterations and reduction of enhanced leukocyte count determined in PH. In conclusion, CBD may be a safe, promising therapeutic or adjuvant therapy agent for the treatment of human pulmonary artery hypertension.

Chronic Cannabidiol Administration Fails to Diminish Blood Pressure in Rats with Primary and Secondary Hypertension Despite Its Effects on Cardiac and Plasma Endocannabinoid System, Oxidative Stress and Lipid Metabolism.

We investigated the influence of cannabidiol (CBD) on blood pressure (BP) and heart rate (HR) in spontaneously (SHR) and deoxycorticosterone (DOCA-salt) hypertensive rats. Hypertension was connected with increases in cardiac and plasma markers of lipid peroxidation in both models, whereas cardiac endocannabinoid levels decreased in SHR and increased in DOCA-salt. CBD (10 mg/kg once a day for 2 weeks) did not modify BP and HR in hypertension but counteracted pro-oxidant effects. Moreover, it decreased cardiac or plasma levels of anandamide, 2-arachidonoylglycerol and oleoyl ethanolamide in DOCA-salt and inhibited the activity of fatty acid amide hydrolase (FAAH) in both models. In the respective normotensive control rats, CBD increased lipid peroxidation, free fatty acid levels and FAAH activity. In conclusion, chronic CBD administration does not possess antihypertensive activity in a model of primary and secondary (DOCA-salt) hypertension, despite its antioxidant effect. The latter may be direct rather than based on the endocannabinoid system. The unexpected CBD-related increase in lipid peroxidation in normotensive controls may lead to untoward effects; thus, caution should be kept if CBD is used therapeutically.

Altered Lipid Metabolism in Blood Mononuclear Cells of Psoriatic Patients Indicates Differential Changes in Psoriasis Vulgaris and Psoriatic Arthritis.

The aim of this study was to investigate possible stress-associated disturbances in lipid metabolism in mononuclear cells, mainly lymphocytes of patients with psoriasis vulgaris (Ps, n = 32) or with psoriatic arthritis (PsA, n = 16) in respect to the healthy volunteers (n = 16). The results showed disturbances in lipid metabolism of psoriatic patients reflected by different phospholipid profiles. The levels of non-enzymatic lipid metabolites associated with oxidative stress 8-isoprostaglandin F2α (8-isoPGF2α) and free 4-hydroxynonenal (4-HNE) were higher in PsA, although levels of 4-HNE-His adducts were higher in Ps. In the case of the enzymatic metabolism of lipids, enhanced levels of endocannabinoids were observed in both forms of psoriasis, while higher expression of their receptors and activities of phospholipases were detected only in Ps. Moreover, cyclooxygenase-1 (COX-1) activity was enhanced only in Ps, but cyclooxygenase-2 (COX-2) was enhanced both in Ps and PsA, generating higher levels of eicosanoids: prostaglandin E1 (PGE1), leukotriene B4 (LTB4), 13-hydroxyoctadecadienoic acid (13HODE), thromboxane B2 (TXB2). Surprisingly, some of major eicosanoids 15-d-PGJ2 (15-deoxy-Δ12,14-prostaglandin J2), 15-hydroxyeicosatetraenoic acid (15-HETE) were elevated in Ps and reduced in PsA. The results of our study revealed changes in lipid metabolism with enhancement of immune system-modulating mediators in psoriatic mononuclear cells. Evaluating further differential stress responses in Ps and PsA affecting lipid metabolism and immunity might be useful to improve the prevention and therapeutic treatments of psoriasis.

Hypertension and chronic inhibition of endocannabinoid degradation modify the endocannabinoid system and redox balance in rat heart and plasma.

The interaction between the endocannabinoid and ROS signaling systems has been demonstrated in different organs. Inhibitors of fatty acid amide hydrolase (FAAH), the key enzyme responsible for degradation of the endocannabinoid anandamide, are postulated to possess anti-hypertensive potential. Here, we compared the effects of hypertension and chronic FAAH inhibition by URB597 on the endocannabinoid system and redox balance in spontaneously hypertensive rats (SHR) and hypertensive deoxycorticosterone acetate (DOCA)-salt rats. Enhanced oxidative stress and lipid peroxidation were found in both hypertension models. Hypertension affected cardiac and plasma endocannabinoid systems in a model-dependent manner: anandamide and 2-arachidonoylglycerol levels decreased in SHR and increased in DOCA-salt. Cardiac CB1 receptor expression increased in both models while higher CB2 receptor expression was only in DOCA-salt. URB597 increased endocannabinoid levels in both models but produced the partial reduction of oxidative stress in DOCA-salt but not in SHR. Notably, URB597 decreased antioxidant defense and increased lipid peroxidation products in normotension. Therefore, the therapeutic potential of FAAH inhibitors should be interpreted cautiously.

The Effect of Long-Term Administration of Fatty Acid Amide Hydrolase Inhibitor URB597 on Oxidative Metabolism in the Heart of Rats with Primary and Secondary Hypertension.

Fatty acid amide hydrolase (FAAH) inhibitor [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate (URB597) may influence redox balance and blood pressure through the modulation of endocannabinoids levels. Therefore, this study aimed to compare changes in oxidative metabolism and apoptosis in the hearts of rats with spontaneous hypertension (SHR) and secondary hypertension (11-deoxycorticosterone acetate; DOCA-salt rats) treated by URB597 via intraperitoneal injection for 14 days. The results showed that URB597 decreased the activity of NADPH and xanthine oxidases in both groups of rats. Moreover, in the heart of SHR rats, URB597 led to an increase of enzymatic and nonenzymatic antioxidant activity and levels (catalase, vitamin C, glutathione/glutathione disulfide [GSH/GSSG]) and upregulation of the thioredoxin system; however, NRf2 expression was downregulated. The opposite effect in relation to Nrf2 activity and the thioredoxin system was observed in DOCA-salt rats after URB597 administration. Despite improvement in antioxidant parameters, URB597 enhanced oxidative modifications of phospholipids (4-hydroxynonenal and isoprostanes) and proteins (carbonyl groups) in SHR heart, whereas 4-hydroxynonenal and carbonyl groups levels decreased in the heart of DOCA-salt rats. Obtained results suggest that examined lipid mediators are involved in peroxisome proliferator-activated receptors (PPAR)-independent and PPAR-dependent modulation of cardiac inflammatory reactions. Furthermore, decreased expression of pro-apoptotic proteins (Bax and caspase 3 and 9) was observed after URB597 administration in the heart of both groups of hypertensive rats, whereas expression of the antiapoptotic protein (Bcl-2) increased in SHR rats. Long-term administration of URB597 altered cardiac redox status depending on the type of hypertension. URB597 enhanced oxidative metabolism and reduced pro-apoptotic factors in the heart of SHR rats, increasing the probability of heart metabolic disorders occurrence or progression.

Crosstalk between liver antioxidant and the endocannabinoid systems after chronic administration of the FAAH inhibitor, URB597, to hypertensive rats.

Hypertension is accompanied by perturbations to the endocannabinoid and antioxidant systems. Thus, potential pharmacological treatments for hypertension should be examined as modulators of these two metabolic systems. The aim of this study was to evaluate the effects of chronic administration of the fatty acid amide hydrolase (FAAH) inhibitor [3-(3-carbamoylphenyl)phenyl]N-cyclohexylcarbamate (URB597) on the endocannabinoid system and on the redox balance in the livers of DOCA-salt hypertensive rats. Hypertension caused an increase in the levels of endocannabinoids [anandamide (AEA), 2-arachidonoyl-glycerol (2-AG) and N-arachidonoyl-dopamine (NADA)] and CB1 receptor and the activities of FAAH and monoacylglycerol lipase (MAGL). These effects were accompanied by an increase in the level of reactive oxygen species (ROS), a decrease in antioxidant activity/level, enhanced expression of transcription factor Nrf2 and changes to Nrf2 activators and inhibitors. Moreover, significant increases in lipid, DNA and protein oxidative modifications, which led to enhanced levels of proapoptotic caspases, were also observed. URB597 administration to the hypertensive rats resulted in additional increases in the levels of AEA, NADA and the CB1 receptor, as well as decreases in vitamin E and C levels, glutathione peroxidase and glutathione reductase activities and Nrf2 expression. Thus, after URB597 administration, oxidative modifications of cellular components were increased, while the inflammatory response was reduced. This study revealed that chronic treatment of hypertensive rats with URB597 disrupts the endocannabinoid system, which causes an imbalance in redox status. This imbalance increases the levels of electrophilic lipid peroxidation products, which later participate in metabolic disturbances in liver homeostasis.

Metabolism of endocannabinoids.

Endocannabinoids belong to a group of ester, ether and amide derivatives of fatty acids, which are endogenous ligands of receptors CB1, CB2, TRPV1 and GPR55 that are included in the endocannabinoid system of the animal organism. The best known endocannabinoids are: N-arachidonylethanolamide called anandamide (AEA) and 2-arachidonoylglycerol (2-AG). They occur in all organisms, and their highest level is observed in the brain. In this review the mechanisms of synthesis and degradation of both AEA and 2-AG are shown. Endocannabinoids are synthesized from phospholipids (mainly phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol) located in the cell membrane. As a result of arachidonic acid transfer from phosphatidylcholine to phosphatidylethanolamine, N-arachidonoyl phosphatidylethanolamine is formed, which is hydrolyzed to AEA by phospholipase D, C and A2. However, 2-AG is formed during the hydrolysis of phosphatidylinositol catalyzed mainly by DAGL. The primary role of endocannabinoids is the activation of cannabinoid receptors. Both AEA and 2-AG are primarily agonists of the CB1 receptor and to a lower degree CB2 and TRPV1r eceptors, but 2-AG has stronger affinity for these receptors. Through activation of receptors, endocannabinoids affect cellular metabolism and participate in the metabolic processes by receptor-independent pathways. Endocannabinoids which are not bound to the receptors are degraded. The main enzymes responsible for the hydrolysis of AEA and 2-AG are FAAH and MAGL, respectively. Apart from hydrolytic degradation, endocannabinoids may also be oxidized by cyclooxygenase-2, lipoxygenases, and cytochrome P450. It has been shown that the metabolites of both endocannabinoids also have biological significance.

Comparison of the Regenerative Metabolic Efficiency of Lipid Extracts from Microalgae Nannochloropsis oceanica and Chlorococcum amblystomatis on Fibroblasts.

UVA radiation leads to oxidative stress and inflammation in skin cells. Therefore, the aim of this study was to compare the effect of lipid extracts from microalgae Nannochloropsis oceanica (N.o.) (marine) and Chlorococcum amblystomatis (C.a.) (freshwater) on the redox balance and PUFA metabolism in human skin fibroblasts modified by UVA. Lipid extracts from both types of microalgae introduced into the fibroblast medium after UVA irradiation significantly reduced the level of ROS and enhanced expression of Nrf2, which increased the activity/level of antioxidants (SOD1/2, CAT, GSH, Trx). The reduction in oxidative stress was accompanied by a decrease in the level of 4-HNE, its protein adducts and protein carbonyl groups. Microalgae also reduced the activity of COX1/2, FAAH and MAGL increased by UVA, and as a consequence, the level of lipid mediators (especially after N.o.) decreased, both from the group of endocannabinoids (AEA, 2-AG, PEA) and eicosanoids (PGE2, 15d-PGJ2, TXB2, 15-HETE), acting mainly through receptors related to G protein, the expression of which increases after UVA. This further contributed to the reduction in oxidative stress and pro-inflammatory signaling at NF-κB and TNFα levels. Therefore, it is suggested that lipid extracts from both N.o. and C.a. microalgae can be used to regenerate fibroblast metabolism disturbed by UVA radiation.

Lipid mediators of cerebrospinal fluid in response to TBE and bacterial co-infections.

Tick-borne diseases are caused by monoinfection or co-infection with different pathogens, including viruses, bacteria and protozoa. Tick-borne diseases are usually accompanied by oxidative stress which promotes the modifications of the host's lipid metabolism. The aim of the study was to compare total antioxidant status and the level of lipid mediators in the cerebrospinal fluid in response to tick-borne encephalitis (TBE) and bacterial co-infections that cause diseases such as that is Lyme borreliosis (LB) and human granulocytic anaplasmosis (HGA). In our study cerebrospinal fluid samples were obtained from 15 patients with TBE and 6 patients with TBE co-infection with LB and/or HGA at admission and after treatment. Control group consisted of 14 patients in whom meningitis was excluded. Total antioxidant status, levels of lipid peroxidation products, endocannabinoids and eicosanoids (determined by liquid and gas chromatography-mass spectrometry) were compared between the groups. It was found that in TBE patients, total antioxidant status was decreased and accompanied by increased levels of lipid peroxidation products (4-HNE, MDA, isoprostanes and neuroprostanes), major endocannabinoids (AEA and 2AG), and eicosanoids (both anti-inflammatory and pro-inflammatory), which generally declined after treatment. On the other hand, in co-infections, significant changes in the levels of some lipid mediators were observed even after the treatment. TBE alone or along with bacterial co-infections promote redox balance disturbances in the cerebrospinal fluid leading to oxidative stress and increased metabolism of phospholipids in the brain tissue reflected in the level of lipid peroxidation products and lipid mediators. Changes in the level of lipid mediators in patients with co-infections after treatment suggest further intensification of metabolic disturbances rather than their resolution.

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.

Influence of Inhibition of COX-2-Dependent Lipid Metabolism on Regulation of UVB-Induced Keratinocytes Apoptosis by Cannabinoids.

Inflammation and apoptosis are regulated by similar factors, including ultraviolet B (UVB) radiation and cannabinoids, which are metabolized by cyclooxygenase-2 (COX-2) into pro-apoptotic prostaglandin derivatives. Thus, the aim of this study was to evaluate the impact of cyclooxygenase-2 inhibition by celecoxib on the apoptosis of keratinocytes modulated by UVB, anandamide (AEA) and cannabidiol (CBD). For this purpose, keratinocytes were non-treated/treated with celecoxib and/or with UVB and CBD and AEA. Apoptosis was evaluated using microscopy, gene expressions using quantitate reverse-transcriptase polymerase chain reaction; prostaglandins using liquid chromatography tandem mass spectrometry and cyclooxygenase activity using spectrophotometry. UVB enhances the percentage of apoptotic keratinocytes, which can be caused by the increased prostaglandin generation by cyclooxygenase-2, or/and induced cannabinoid receptor 1/2 (CB1/2) expression. AEA used alone intensifies apoptosis by affecting caspase expression, and in UVB-irradiated keratinocytes, cyclooxygenase-2 activity is increased, while CBD acts as a cytoprotective when used with or without UVB. After COX-2 inhibition, UVB-induced changes are partially ameliorated, when anandamide becomes an anti-apoptotic agent. It can be caused by observed reduced generation of anandamide pro-apoptotic derivative prostaglandin-ethanolamide by COX. Therefore, products of cyclooxygenase-dependent lipid metabolism seem to play an important role in the modulation of UVB-induced apoptosis by cannabinoids, which is particularly significant in case of AEA as inhibition of cyclooxygenase reduces the generation of pro-apoptotic lipid mediators and thus prevents apoptosis.

Changes in Hepatic Phospholipid Metabolism in Rats under UV Irradiation and Topically Treated with Cannabidiol.

The liver is a key metabolic organ that is particularly sensitive to environmental factors, including UV radiation. As UV radiation induces oxidative stress and inflammation, natural compounds are under investigation as one method to counteract these consequences. The aim of this study was to assess the effect of topical application of phytocannabinoid-cannabidiol (CBD) on the skin of nude rats chronically irradiated with UVA/UVB, paying particular attention to its impact on the liver antioxidants and phospholipid metabolism. The results of this study indicate that CBD reaches the rat liver where it is then metabolized into decarbonylated cannabidiol, 7-hydroxy-cannabidiol and cannabidiol-glucuronide. CBD increased the levels of GSH and vitamin A after UVB radiation. Moreover, CBD prevents the increase of 4-hydroxynonenal and 8-iso-prostaglandin-F2α levels in UVA-irradiated rats. As a consequence of reductions in phospholipase A2 and cyclooxygenases activity following UV irradiation, CBD upregulates the level of 2-arachidonoylglycerol and downregulates prostaglandin E2 and leukotriene B4. Finally, CBD enhances decreased level of 15-deoxy-Δ-12,14-prostaglandin J2 after UVB radiation and 15-hydroxyeicosatetraenoic acid after UVA radiation. These data show that CBD applied to the skin prevents ROS- and enzyme-dependent phospholipid metabolism in the liver of UV-irradiated rats, suggesting that it may be used as an internal organ protector.

Exogenous Antioxidants Impact on UV-Induced Changes in Membrane Phospholipids and the Effectiveness of the Endocannabinoid System in Human Skin Cells.

Natural antioxidants effectively counteract changes caused by UV radiation in human skin cells. However, their action is limited due to their lipo/hydrophilicity. Therefore, the aim of this study was to analyze the mutual protective action of hydrophilic ascorbic acid and partially lipophilic rutin against UVA/UVB-induced changes in membranes phospholipid and endocannabinoid system in keratinocytes and fibroblasts. Obtained results clearly showed that, despite the stronger antioxidant properties of ascorbic acid, the lipid membranes were more effectively protected against UV-induced oxidation by rutin, including changes in phospholipid fatty acid levels, prevention against reactive aldehydes formation and endocannabinoids degradation. Ascorbic acid more strongly prevented UV-induced endocannabinoid receptors expression in fibroblasts, especially CB1. However, the combined action of used antioxidants resulted in the greatest cytoprotective effect, which was evident in the inflammatory marker TNFα down-regulation and increased cell viability following cell irradiation. The applied mixture of antioxidants showed a stronger protective in relation to membrane phospholipids in keratinocytes and in the endocannabinoid system in fibroblasts. In conclusion, it can be suggested that combined antioxidant capacities of ascorbic acid and rutin protects against lipid peroxidation but also decreases the UV-induced inflammation by direct interaction with the endocannabinoid system, thus increasing skin cell viability.

Oxidative Stress and Its Consequences in the Blood of Rats Irradiated with UV: Protective Effect of Cannabidiol.

UVA/UVB radiation disturbs the redox balance of skin cells, and metabolic consequences can be transferred into the blood and internal tissues, especially after chronic skin exposure to UV radiation. Therefore, the aim of this study was to evaluate the effect of cannabidiol (CBD), an antioxidant and anti-inflammatory phytocannabinoid, on oxidative stress and its consequences in the blood of nude rats whose skin was exposed to UVA/UVB radiation for 4 weeks. It was shown that CBD penetrated the blood and in UVB-irradiated rats was preferentially located in the membranes of polymorphonuclear leukocytes, which promoted reduction of ROS generation and up-regulation of antioxidant ability by increasing the activity of glutathione reductase and thioredoxin reductase, while the level of reduced glutathione decreased by UV radiation. Consequently, reduction in UV-induced lipid peroxidation, assessed as 4-hydroxynonenal (4-HNE) and 8-isoprostane (8-isoPGF2α) as well as protein modifications, estimated as 4-HNE-protein adducts and protein carbonyl groups, was observed. CBD, by countering the UV-induced down-regulation of 2-arachidonylglycerol, promoted its antioxidant/anti-inflammatory effects by reducing CB1 and increasing PPARγ receptor activation and consequently ROS and TNF-α down-regulation. The results suggest that CBD applied topically to the skin minimizes redox changes not only at the skin level, but also at the systemic level.

Vasoprotective Endothelial Effects of Chronic Cannabidiol Treatment and Its Influence on the Endocannabinoid System in Rats with Primary and Secondary Hypertension.

Our study aimed to examine the endothelium (vascular)-protecting effects of chronic cannabidiol (CBD) administration (10 mg/kg once daily for 2 weeks) in aortas and small mesenteric (G3) arteries isolated from deoxycorticosterone-induced hypertensive (DOCA-salt) rats and spontaneously hypertensive rats (SHR). CBD reduced hypertrophy and improved the endothelium-dependent vasodilation in response to acetylcholine in the aortas and G3 of DOCA-salt rats and SHR. The enhancement of vasorelaxation was prevented by the inhibition of nitric oxide (NO) with L-NAME and/or the inhibition of cyclooxygenase (COX) with indomethacin in the aortas and G3 of DOCA-salt and SHR, respectively. The mechanism of the CBD-mediated improvement of endothelial function in hypertensive vessels depends on the vessel diameter and may be associated with its NO-, the intermediate-conductance calcium-activated potassium channel- or NO-, COX-, the intermediate and the small-conductance calcium-activated potassium channels-dependent effect in aortas and G3, respectively. CBD increased the vascular expression of the cannabinoid CB1 and CB2 receptors and aortic levels of endocannabinoids with vasorelaxant properties e.g., anandamide, 2-arachidonoylglycerol and palmitoyl ethanolamide in aortas of DOCA-salt and/or SHR. In conclusion, CBD treatment has vasoprotective effects in hypertensive rats, in a vessel-size- and hypertension-model-independent manner, at least partly via inducing local vascular changes in the endocannabinoid system.

The FAAH Inhibitor URB597 Modulates Lipid Mediators in the Brain of Rats with Spontaneous Hypertension.

Hypertension is accompanied by oxidative stress, which can be modified by the functioning of the endocannabinoid system playing a prominent modulatory role in the brain. The present study tested whether chronic administration of the fatty acid amide hydrolase (FAAH) inhibitor [3-(3-carbamoylphenyl) phenyl]N-cyclohexylcarbamate (URB597) to rats with primary hypertension (SHR) can modify redox balance and consequently brain phospholipid metabolism. Experiments were conducted using SHRs and normotensive control Wistar-Kyoto rats treated by intraperitoneal injection with URB597 for 14 days. The biochemical parameters were assayed in the rats' brains. Inhibition of FAAH activity by URB597 resulted in an increase in anandamide and GPR55 receptor levels, as well as a decrease in CB2 receptor expression. However, there was a simultaneous increase in Nrf2 expression, as well as Cu, Zn-SOD, GSH-Px, glutathione reductase activity, and vitamin E levels in brain tissue of SHR rats. Consequently, URB597 caused a decrease in levels of phospholipid fatty acids and MDA, and an increase in free fatty acids. Given the importance of maintaining redox balance for brain function, the results of this study point to endocannabinoids as a potential therapeutic target for preventing brain metabolic disorders in hypertension.