Protective Effects of Cannabidivarin and Cannabigerol on Cells of the Blood-Brain Barrier Under Ischemic Conditions

Background and Objectives: Preclinical studies have shown cannabidiol is protective in models of ischemic stroke. Based on results from our recent systematic review, we investigated the effects of two promising neuro-protective phytocannabinoids, cannabigerol (CBG) and cannabidivarin (CBDV), on cells of the blood-brain barrier (BBB), namely human brain microvascular endothelial cells (HBMECs), pericytes, and astrocytes. Experimental Approach: Cultures were subjected to oxygen-glucose deprivation (OGD) protocol to model is-chemic stroke and cell culture medium was assessed for cytokines and adhesion molecules post-OGD. Astrocyte cell lysates were also analyzed for DNA damage markers. Antagonist studies were conducted where appropriate to study receptor mechanisms. Results: In astrocytes CBG and CBDV attenuated levels of interleukin-6 and lactate dehydrogenase (LDH), whereas CBDV (10 nM-10 lM) also decreased vascular endothelial growth factor secretion. CBDV (300 nM-10 lM) attenuated levels of monocyte chemoattractant protein (MCP)-1 in HBMECs. In astrocytes, CBG decreased levels of DNA damage proteins, including p53, whereas CBDV increased levels of DNA damage markers. Antagonists for CB 1 , CB 2 , PPAR-c, PPAR-a, 5-HT1 A , and TRPV1 had no effect on CBG (3 lM) or CBDV (1 lM)-mediated decreases in LDH in astrocytes. GPR55 and GPR18 were partially implicated in the effects of CBDV, but no molecular target was identified for CBG. Conclusions: We show that CBG and CBDV display neuroprotective properties in three different cells that constitute the BBB, modulating different hallmarks of ischemic stroke pathophysiology. These data enhance our understanding of the protective effects of CBG and CBDV and warrant further investigation into these compounds in ischemic stroke. Future studies should identify other possible neuroprotective effects of CBG and CBDV and their corresponding mechanisms of action

A systematic review on the pharmacokinetics of cannabidiol in humans

Background: Cannabidiol is being pursued as a therapeutic treatment for multiple conditions, usually by oral delivery. Animal studies suggest oral bioavailability is low, but literature in humans is not sufficient. The aim of this review was to collate published data in this area.Methods: A systematic search of PubMed and EMBASE (including MEDLINE) was conducted to retrieve all articles reporting pharmacokinetic data of CBD in humans. Results: Of 792 articles retireved, 24 included pharmacokinetic parameters in humans. The half-life of cannabidiol was reported between 1.4-10.9 hours after oromucosal spray, 2-5 days after chronic oral administration, 24 hours after i.v., and 31 hours after smoking. Bioavailability following smoking was 31% however no other studies attempted to report the absolute bioavailability of CBD following other routes in humans, despite i.v formulations being available. The area-under-the-curve and Cmax increase in dose-dependent manners and are reached quicker following smoking/inhalation compared to oral/oromucosal routes. Cmax is increased during fed states and in lipid formulations. Tmax is reached between 0-4 hours. Conclusions: This review highlights the paucity in data and some discrepancy in the pharmacokinetics of cannabidiol, despite its widespread use in humans. Analysis and understanding of properties such as bioavailability and half-life is critical to future therapeutic success, and robust data from a variety of formulations is required

Remote effects of acute kidney injury in a porcine model

Background: Acute Kidney Injury (AKI) is a common and serious disease with no specific treatment. An episode of AKI may affect organs distant to the kidney, further increasing the morbidity associated with AKI. The mechanism of organ cross-talk after AKI is unclear. The renal and immune systems of pigs and humans are alike. Using a preclinical animal (porcine) model, we test the hypothesis that early effects of AKI on distant organs is by immune cell infiltration leading to inflammatory cytokine production, extravasation and edema. Study Design: In 29 pigs exposed to either sham-surgery or renal ischemia-reperfusion (control, n=12; AKI, n=17) we assessed remote organ (liver, lung, brain) effects in the short-(from 2 to 48h reperfusion) and longer-term (5 weeks later) using immunofluorescence (for leucocyte infiltration, apoptosis), a cytokine array, tissue elemental analysis (electrolytes), blood hematology and chemistry (e.g. liver enzymes) and PCR (for inflammatory markers). Results: AKI elicited significant, short-term (~24h) increments in enzymes indicative of acute liver damage (e.g. AST:ALT ratio; P=0.02) and influenced tissue biochemistry in some remote organs (e.g. lung tissue [Ca++] increased; P=0.04). These effects largely resolved after 48h and no further histopathology, edema, apoptosis or immune cell infiltration was noted in liver, lung or hippocampus in the short- and longer-term. Conclusions: AKI has subtle biochemical effects on remote organs in the short-term including a transient increment in markers of acute liver damage. These effects resolved by 48h and no further remote organ histopathology, apoptosis, edema or immune cell infiltration was noted

Correlations of <i>in vivo</i> cardiovascular data with <i>ex vivo</i> vasoactive responses of arteries obtained from HD patients to different stimuli.

<p>Correlations of <i>in vivo</i> cardiovascular data with <i>ex vivo</i> vasoactive responses of arteries obtained from HD patients to different stimuli.</p

Concentration-response curves to U46619 (A,B), Ang II (C,D), and vasopressin (E,F) in arteries obtained from HD patients and controls.

<p>Data are expressed as mean ± SEM and the comparison is by students t-test; **<i>P</i><0.001, ***<i>P</i><0.001, ****<i>P</i><0.0001. HD, haemodialysis; U4, U46619; n, number of arteries; M, molar; mN, milliNewtons.</p

Concentration-response curves to sodium nitroprusside in arteries obtained from HD patients and controls.

<p>Data are expressed as mean ± SEM and the comparison is by student's t-test. HD, haemodialysis; n, number of arteries; M, molar.</p

Concentration-response curves to NA (A,B) and ET-1 (C,D) in isolated subcutaneous arteries obtained from HD patients and controls.

<p>Data are expressed as mean ± SEM and the comparison is by students t-test; *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001. HD, haemodialysis; n, number of arteries; M, molar; mN, milliNewtons.</p

Correlations of <i>in vivo</i> data with <i>ex vivo</i> normalised vasoconstrictor responses of arteries obtained from HD patients.

<p>Correlations of <i>in vivo</i> data with <i>ex vivo</i> normalised vasoconstrictor responses of arteries obtained from HD patients.</p

Concentration-response curves to bradykinin (A,B,C) and acetylcholine (D,E,F) in arteries obtained from HD patients and controls.

<p>Data are expressed as mean ± SEM and the comparison is by students t-test; *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001, ****<i>P</i><0.0001. HD, haemodialysis; n, number of arteries; M, molar.</p

Physical characteristic of HD patients and controls (non HD subjects).

<p>Physical characteristic of HD patients and controls (non HD subjects).</p