Activation of Endocannabinoid Receptor 2 as a Mechanism of Propofol Pretreatment-Induced Cardioprotection against Ischemia-Reperfusion Injury in Rats

Re-evaluation of the cardioprotective effects of cannabinoids against ischemia-reperfusion injury according to the IMproving Preclinical Assessment of Cardioprotective Therapies (IMPACT) criteria

Ischemic heart disease, associated with high morbidity and mortality, represents a major challenge for the development of drug-based strategies to improve its prognosis. Results of pre-clinical studies suggest that agonists of cannabinoid CB2 receptors and multitarget cannabidiol might be potential cardioprotective strategies against ischemia-reperfusion injury. The aim of our study was to re-evaluate the cardioprotective effects of cannabinoids against ischemia-reperfusion injury according to the IMproving Preclinical Assessment of Cardioprotective Therapies (IMPACT) criteria published recently by the European Union (EU) CARDIOPROTECTION COST ACTION. To meet the minimum criteria of those guidelines, experiments should be performed (i) on healthy small animals subjected to ischemia with reperfusion lasting for at least 2 hours and (ii) confirmed in small animals with comorbidities and co-medications and (iii) in large animals. Our analysis revealed that the publications regarding cardioprotective effects of CB2 receptor agonists and cannabidiol did not meet all three strict steps of IMPACT. Thus, additional experiments are needed to confirm the cardioprotective activities of (endo)cannabinoids mainly on small animals with comorbidities and on large animals. Moreover, our publication underlines the significance of the IMPACT criteria for a proper planning of preclinical experiments regarding cardiac ischemia-reperfusion injury.

Construction of preclinical evidence for propofol in the treatment of reperfusion injury after acute myocardial infarction: A systematic review and meta-analysis

Propofol, a commonly used intravenous anesthetic, has demonstrated potential in protecting against myocardial ischemia/reperfusion injury (MIRI) based on preclinical animal studies. However, the clinical benefits of propofol in this context are subject to debate. We conducted a systematic search across eight databases to identify all relevant animal studies investigating the preventive effects of propofol on MIRI until October 30, 2023. We assessed the methodological quality of the included studies using SYRCLE's bias risk tool. Statistical analysis was performed using STATA 15.1. The primary outcome measures analyzed in this study were myocardial infarct size (IS) and myocardial injury biomarkers. This study presents a comprehensive analysis of 48 relevant animal studies investigating propofol's preventive effects on MIRI. Propofol administration demonstrated a reduction in myocardial IS and decreased levels of myocardial injury biomarkers (CK-MB, LDH, cTnI). Moreover, propofol improved myocardial function parameters (+dp/dtmax, -dP/dtmax, LVEF, LVFS), exhibited favorable effects on inflammatory markers (IL-6, TNF-α) and oxidative stress markers (SOD, MDA), and reduced myocardial cell apoptotic index (AI). These findings suggest propofol exerts cardioprotective effects by reducing myocardial injury, decreasing infarct size, and improving heart function. However, the absence of animal models that accurately represent comorbidities such as aging and hypertension, as well as inconsistent administration methods that align with clinical practice, may hinder its clinical translation. Further robust investigations are required to validate these findings, elucidate the underlying mechanisms of propofol, and facilitate its potential translation into clinical practice.

Mechanistic Implications of GSK and CREB Crosstalk in Ischemia Injury

Ischemia-reperfusion (IR) injury is a damage to an organ when the blood supply is less than the demand required for normal functioning, leading to exacerbation of cellular dysfunction and death. IR injury occurs in different organs like the kidney, liver, heart, brain, etc., and may not only involve the ischemic organ but also cause systemic damage to distant organs. Oxygen-glucose deprivation in cells causes oxidative stress, calcium overloading, inflammation, and apoptosis. CREB is an essential integrator of the body's various physiological systems, and it is widely accepted that dysfunction of CREB signaling is involved in many diseases, including ischemia-reperfusion injury. The activation of CREB can provide life to a cell and increase the cell's survival after ischemia. Hence, GSK/CREB signaling pathway can provide significant protection to cells of different organs after ischemia and emerges as a futuristic strategy for managing ischemia-reperfusion injury. Different signaling pathways such as MAPK/ERK, TLR4/MyD88, RISK, Nrf2, and NF-κB, get altered during IR injury by the modulation of GSK-3 and CREB (cyclic AMP response element (CRE)-binding protein). GSK-3 (protein kinase B) and CREB are the downstream targets for fulfilling the roles of various signaling pathways. Calcium overloading during ischemia increases the expression of calcium-calmodulin-dependent protein kinase (CaMK), which subsequently activates CREB-mediated transcription, thus promoting the survival of cells. Furthermore, this review highlights the crosstalk between GSK-3 and CREB, promoting survival and rendering the cells resistant to subsequent severe ischemia.

C57BL/6J and C57BL/6N mice exhibit different neuro-behaviors and sensitivity to midazolam- and propofol-induced anesthesia

Phenotypes of inbred mice are strain-dependent, indicating the important influence of genetic background in biomedical research. C57BL/6 is one of the most commonly used inbred mouse strains, and its two closely related substrains, C57BL/6J and C57BL/6N, have been separated for only about 70 years. These two substrains have accumulated genetic variations and exhibit different phenotypes, but it remains unclear whether they respond to anesthetics differently. In this study, commercially acquired wildtype C57BL/6J or C57BL/6N mice from two different sources were analyzed and compared for their response to a spectrum of anesthetics (midazolam, propofol, esketamine or isoflurane anesthesia) and their performance in a series of behavioral tests associated with neurological functions including open field test (OFT), elevated plus maze (EPM), Y maze, prepulse inhibition (PPI), tail strain test (TST) and forced swimming test (FST). Loss of the righting reflex (LORR) is used to measure the anesthetic effects. Our results suggested that the anesthesia induction time induced by either of the four anesthetics were comparable for the C57BL/6J and C57BL/6N mice. However, C57BL/6J or C57BL/6N mice do exhibit different sensitivity to midazolam and propofol. The anesthesia duration of midazolam of C57BL/6J mice was about 60% shorter than that of the C57BL/6N mice, while the LORR duration induced by propofol in C57BL/6J mice was 51% longer than that of the C57BL/6N. In comparison, the two substrains were anesthetized by esketamine or isoflurane similarly. In the behavioral analysis, the C57BL/6J mice exhibited a lower level of anxiety- and depression-like behaviors in OFT, EPM, FST and TST than the C57BL/6N mice. Locomotor activity and sensorimotor gating of these two substrains remained comparable. Our results stress the point that when selecting inbred mice for allele mutation or behavioral testing, the influence of even subtle differences in genetic background should be fully considered.

Propofol inhibits myocardial injury induced by microvesicles derived from hypoxia-reoxygenated endothelial cells via lncCCT4-2/CCT4 signaling

BACKGROUND

Ischemia-reperfusion (IR) induces increased release of extracellular vesicles in the heart and exacerbates myocardial IR injury. We have previously shown that propofol attenuates hypoxia/reoxygenation (HR)-induced injury in human umbilical vein endothelial cells (HUVECs) and that microvesicles derived from propofol-treated HUVECs inhibit oxidative stress in endothelial cells. However, the role of microvesicles derived from propofol post-treated HUVECs ((HR + P)-EMVs) in IR-injured cardiomyocytes is unclear. In this study, we aimed to investigate the role of (HR + P)-EMVs in cardiac IR injury compared to microvesicles derived from hypoxic/reoxygenated HUVECs (HR-EMVs) and to elucidate the underlying mechanisms.

METHODS

Hypoxia/reoxygenation (HR) models of HUVECs and AC16 cells and a mouse cardiac IR model were established. Microvesicles from HR-injured HUVECs, DMSO post-treated HUVECs and propofol post-treated HUVECs were extracted by ultra-high speed centrifugation, respectively. The above EMVs were co-cultured with HR-injured AC16 cells or injected intracardially into IR mice. Flow cytometry and immunofluorescence were used to determine the levels of oxidative stress and apoptosis in cardiomyocytes. Apoptosis related proteins were detected by Western blot. Echocardiography for cardiac function and Evans blue-TTC staining for myocardial infarct size. Expression of lncCCT4-2 in EMVs and AC16 cells was analysed by whole transcriptome sequencing of EMVs and RT-qPCR. The molecular mechanism of inhibition of myocardial injury by (HR + P)-EMVs was elucidated by lentiviral knockdown of lncCCT4-2, plasmid overexpression or knockdown of CCT4, and actinomycin D assay.

RESULTS

In vitro and in vivo experiments confirmed that HR-EMVs exacerbated oxidative stress and apoptosis in IR-injured cardiomyocytes, leading to increased infarct size and worsened cardiac function. Notably, (HR + P)-EMVs induced significantly less oxidative stress and apoptosis in IR-injured cardiomyocytes compared to HR-EMVs. Mechanistically, RNA sequencing of EMVs and RT-qPCR showed that lncCCT4-2 was significantly upregulated in (HR + P)-EMVs and cardiomyocytes co-cultured with (HR + P)-EMVs. Reduction of lncCCT4-2 in (HR + P)-EMVs enhanced oxidative stress and apoptosis in IR-injured cardiomyocytes. Furthermore, the anti-apoptotic activity of lncCCT4-2 from (HR + P)-EMVs was achieved by increasing the stability of CCT4 mRNA and promoting the expression of CCT4 protein in cardiomyocytes.

CONCLUSIONS

Our study showed that (HR + P)-EMVs uptake by IR-injured cardiomyocytes upregulated lncCCT4-2 in cardiomyocytes and promoted CCT4 expression, thereby inhibiting HR-EMVs induced oxidative stress and apoptosis.

Protective effect of fatty acid amide hydrolase inhibitor URB597 and monoacylglycerol lipase inhibitor KML29 on renal ischemia-reperfusion injury via toll-like receptor 4/nuclear factor-kappa B pathway

BACKGROUND

Arachidonoyl ethanolamide (anandamide, AEA) and 2-arachidonoylglycerol (2-AG) are the most studies endocannabinoids. AEA and 2-AG are degraded by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) enzymes, respectively. FAAH and MAGL enzymes are widely expressed in many tissues, including kidney. Recent works have depicted that AEA and 2-AG levels are associated with ischemia-reperfusion (IR) injury. In this study, we investigated the effects of MAGL inhibitor KML29 and FAAH inhibitor URB597 against kidney IR injury.

METHODS

The kidneys of the rats underwent ischemia for 45 min and then reperfusion for 24 h. KML29 and URB597 were administered intraperitoneally with kidney IR to two different treatment groups.

RESULTS

IR application increased serum blood urea nitrogen (BUN), creatinine (Cre), interleukin-18 (IL-18), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1) levels, while these parameters were decreased following KML29 and URB597 administration. KML29 and URB597 administration also reduced the increased toll-like receptor-4 (TRL-4), phosphorylated-NF-κB, phosphorylated-IκB-α, tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β), interleukin-6 (IL-6), caspase-3 levels and histopathological damage in kidney tissue.

CONCLUSIONS

Our results reveal that MAGL inhibitor KML29 and FAAH inhibitor URB597 have a protective effect on kidney IR injury by preventing apoptosis and inflammation. Inhibition of MAGL and FAAH may be a new therapeutic strategy to prevent kidney IR injury.

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.

Curcumin Protects Diabetic Mice against Isoproterenol-Induced Myocardial Infarction by Modulating CB2 Cannabinoid Receptors

Molecular docking revealed curcumin as a potent CB2 cannabinoid receptor (CB2R) agonist. Since CB2R is involved in cardioprotective functions, we explored its role in ameliorative actions of curcumin against myocardial damage triggered by isoproterenol in diabetic animals. Mice were kept on a high-fat diet (HFD) throughout the experiment (30 days). Following 7 days of HFD feeding, streptozotocin was administered (150 mg/kg, intraperitoneal) to induce diabetes. From day 11 to 30, diabetic mice received either curcumin (100 or 200 mg/kg/day, oral), CB2R antagonist AM630 (1 mg/kg/day, intraperitoneal) or both, with concurrent isoproterenol (150 mg/kg, subcutaneous) administration on day 28 and 29. Diabetic mice with myocardial infarction showed an altered hemodynamic pattern and lipid profile, reduced injury markers, antioxidants with increased lipid peroxidation in the myocardium, and elevated glucose and liver enzymes in the blood. Moreover, an increased pro-inflammatory markers, histological severity, myonecrosis, and edema were observed. Curcumin compensated for hemodynamic fluctuations, restored biochemical markers, preserved antioxidant capacity, decreased cytokines levels, and restored cardiac functionality. However, the AM630 pre-treatment attenuated the effects of curcumin. The data suggest the involvement of CB2R in the actions of curcumin such as in the prevention of myocardial stress and in the improvement of the normal status of the myocardial membrane associated with diabetes.

Why Do Marijuana and Synthetic Cannabimimetics Induce Acute Myocardial Infarction in Healthy Young People?

The use of cannabis preparations has steadily increased. Although cannabis was traditionally assumed to only have mild vegetative side effects, it has become evident in recent years that severe cardiovascular complications can occur. Cannabis use has recently even been added to the risk factors for myocardial infarction. This review is dedicated to pathogenetic factors contributing to cannabis-related myocardial infarction. Tachycardia is highly important in this respect, and we provide evidence that activation of CB₁ receptors in brain regions important for cardiovascular regulation and of presynaptic CB₁ receptors on sympathetic and/or parasympathetic nerve fibers are involved. The prototypical factors for myocardial infarction, i.e., thrombus formation and coronary constriction, have also been considered, but there is little evidence that they play a decisive role. On the other hand, an increase in the formation of carboxyhemoglobin, impaired mitochondrial respiration, cardiotoxic reactions and tachyarrhythmias associated with the increased sympathetic tone are factors possibly intensifying myocardial infarction. A particularly important factor is that cannabis use is frequently accompanied by tobacco smoking. In conclusion, additional research is warranted to decipher the mechanisms involved, since cannabis use is being legalized increasingly and Δ⁹-tetrahydrocannabinol and its synthetic analogue nabilone are indicated for the treatment of various disease states.

Cardiotoxicity of Fluoropyrimidines: Epidemiology, Mechanisms, Diagnosis, and Management

Cancer is a growing public health problem; it is responsible annually for millions of deaths worldwide. Fluoropyrimidines are highly effective and commonly prescribed anti-neoplastic drugs used in a wide range of chemotherapy regimens against several types of malignancies. 5-fluorouracil and its prodrugs affect neoplastic cells in multiple ways by impairing their proliferation, principally through the inhibition of thymidylate synthase. Fluoropyrimidine-induced cardiotoxicity was described more than 50 years ago, but many details such as incidence, mechanisms, and treatment are unclear and remain disputed. Severe cardiotoxicity is not only life-threatening, but also leads to withdrawal from an optimal chemotherapy regimen and decreases survival rate. Differences in the frequency of cardiotoxicity are explained by different chemotherapy schedules, doses, criteria, and populations. Proposed pathophysiological mechanisms include coronary vasospasm, endothelial damage, oxidative stress, Krebs cycle disturbances, and toxic metabolites. Such varied pathophysiology of the cardiotoxicity phenomenon makes prevention and treatment more difficult. Cardiovascular disturbances, including chest pain, arrhythmias, and myocardial infarction, are among the most common side effects of this class of anti-neoplastic medication. This study aims to summarize the available data on fluoropyrimidine cardiotoxicity with respect to symptoms, incidence, metabolism, pathophysiological mechanism, diagnosis, management, and resistance.

Cannabidiol-mediated RISK PI3K/AKT and MAPK/ERK pathways decreasing reperfusion myocardial damage

Myocardial ischemia continues to be the first cause of morbimortality in the world; the definitive treatment is reperfusion; however, this action causes additional damage to ischemic myocardial tissue; this forces to seek therapies of cardioprotection to reduce this additional damage. There are many cardioprotective agents; within these, cannabinoids have shown to have beneficial effects, mainly cannabidiol (CBD). CBD is a non psychoactive cannabinoid. To evaluate the effect in experimental models of CBD in myocardial ischemia reperfusion in rats, twelve-week-old male rats have been used. The animals were divides in 3 groups: control(C), ischemia reperfusion (IR) and CBD pretreatment (1/day/5mg/kg /10days). Langendorff organ isolate studies were performed, and the area of infarction was assessed with triphenyl tetrazolium, in addition to molecular analysis of AT1 and AT2 receptors and Akt and Erk proteins and their phosphorylated forms related to RISK pathways. It was observed that there is an improvement with the use of CBD increasing inotropism and cardiac lusitropism, improving considerably the cardiovascular functionality. These could be related to the reduction of the area of infarction and activation of the AT2 receptor and the RISK pathway with absence of activation of the AT2 receptor (these could relate the reduction of the infarct area and the restoration of cardiovascular function with the activation of the AT2 receptor and the RISK pathway with the absence of activation of the AT2 receptor). The use of cannabinoids was shown to have beneficial effects when used as a treatment for myocardial reperfusion damage.

Human umbilical cord mesenchymal stem cells-derived exosomal microRNA-181a retards nasopharyngeal carcinoma development by mediating KDM5C

OBJECTIVE

It has been studied that mesenchymal stem cells (MSCs)-derived exosomes could suppress tumor growth in nasopharyngeal carcinoma (NPC) and microRNA-181a (miR-181a) could mediate drug resistance in NPC. Focused on this work, the mechanism of human umbilical cord MSCs (hUC-MSCs)-derived exosomal miR-181a was explored in NPC cell progression.

METHODS

NPC tissues and normal tissues were obtained from patients, and miR-181a and KDM5C expression was examined. hUC-MSCs-derived exosomes were extracted, identified and co-cultured with NPC cells (C666-1 and SUNE1). C666-1 cell progression in vitro and/or tumor growth in vivo were examined after incubation with exosomes, miR-181a or lysine-specific demethylase 5C (KDM5C). miR-181a and KDM5C expression were examined in NPC.

RESULTS

miR-181a expression was reduced while KDM5C expression was elevated in NPC. hUC-MSCs-derived exosomes restrained NPC cell growth in vivo and in vitro. Depleting or restoring exosomal miR-181a promoted or delayed NPC cell progression. KDM5C silencing suppressed NPC cell progression.

CONCLUSION

This study concluded that hUC-MSCs-derived exosomal miR-181a retards NPC development via negatively modulating KDM5C, serving as a candidate reference for the therapy of NPC.

Restoration of NRF2 attenuates myocardial ischemia reperfusion injury through mediating microRNA-29a-3p/CCNT2 axis

Accumulated studies have been implemented for comprehending the mechanism of myocardial ischemia reperfusion injury (MI/RI). Nuclear factor erythroid-2 related factor 2 (NRF2)-mediated transcription activity in MI/RI has not been completely interpreted from the perspective of microRNA-29a-3p (miR-29a-3p) and cyclin T2 (CCNT2). Therein, this study intends to decode the mechanism of NRF2/miR-29a-3p/CCNT2 axis in MI/RI. Rat MI/RI models were established by left anterior descending artery ligation. Rats were injected with NRF2 or CCNT2 overexpression plasmids or miR-29a-3p agomir to explore their effects on MI/RI. Hypoxia/reoxygenation (H/R) cardiomyocytes were established and transfected with restored NRF2 or miR-29a-3p or CCNT2 for further exploration of their roles. NRF2, miR-29a-3p, and CCNT2 expression in myocardial tissues in rats with MI/RI and in cardiomyocytes in H/R injury were detected. ChIP assay verified the relationship between miR-29a-3p and NRF2, and the bioinformatics software and dual-luciferase reporter experiment verified the interaction between miR-29a-3p and CCNT2. NRF2 and miR-29a-3p were down-regulated while CCNT2 was up-regulated in myocardial tissues in rats with MI/RI and in H/R-treated cardiomyocytes. Restoration of NRF2 or miR-29a-3p improved hemodynamics and myocardial injury and suppressed serum inflammation and cardiomyocyte apoptosis via CCNT2 in rats with MI/RI. Upregulation of NRF2 or miR-29a-3p inhibited LDH and CK-MB activities, oxidative stress, and apoptosis and promoted viability of cardiomyocytes with H/R injury. NRF2 bound to the promoter of miR-29a-3p and CCNT2 was targeted by miR-29a-3p. This study elucidates that up-regulating NRF2 or miR-29a-3p attenuates MI/RI via inhibiting CCNT2, which may renew the existed knowledge of MI/RI-related mechanism and provide a novel guidance toward MI/RI treatment.

Cannabinoids in Metabolic Syndrome and Cardiac Fibrosis

PURPOSE OF REVIEW

This article provides a concise overview of how cannabinoids and the endocannabinoid system (ECS) have significant implications for the prevention and treatment of metabolic syndrome (MetS) and for the treatment of cardiovascular disorders, including cardiac fibrosis.

RECENT FINDINGS

Over the past few years, the ECS has emerged as a pivotal component of the homeostatic mechanisms for the regulation of many bodily functions, including inflammation, digestion, and energy metabolism. Therefore, the pharmacological modulation of the ECS by cannabinoids represents a novel strategy for the management of many diseases. Specifically, increasing evidence from preclinical research studies has opened new avenues for the development of cannabinoid-based therapies for the management and potential treatment of MetS and cardiovascular diseases. Current information indicates that modulation of the ECS can help maintain overall health and well-being due to its homeostatic function. From a therapeutic perspective, cannabinoids and the ECS have also been shown to play a key role in modulating pathophysiological states such as inflammatory, neurodegenerative, gastrointestinal, metabolic, and cardiovascular diseases, as well as cancer and pain. Thus, targeting and modulating the ECS with cannabinoids or cannabinoid derivatives may represent a major disease-modifying medical advancement to achieve successful treatment for MetS and certain cardiovascular diseases.

Dexmedetomidine Ameliorates Lung Injury Induced by Intestinal Ischemia/Reperfusion by Upregulating Cannabinoid Receptor 2, Followed by the Activation of the Phosphatidylinositol 3-Kinase/Akt Pathway

Intestinal ischemia/reperfusion (I/R) is a clinical emergency, which often causes lung injury with high morbidity and mortality. Although dexmedetomidine has been identified to have a protective effect on lung injury caused by intestinal I/R, its specific mechanism is still elucidated. In recent years, the cannabinoid (CB₂) receptor pathway has been found to be involved in I/R injury of some organs. In the current study, we investigated whether the CB₂ receptor pathway contributes to the protective effect of dexmedetomidine on the intestinal I/R-induced lung injury in rats. Dexmedetomidine treatment upregulated the expression of CB₂ receptor and suppressed the I/R-induced increases in lung injury scores, inflammatory cell infiltration, lung wet/dry ratio, MPO activity, MDA level, inflammatory cytokines, and caspase-3 expression while augmenting SOD activity and Bcl-2 expression, indicating attenuation of lung injury. Dexmedetomidine treatment also increased the expression of Akt. The protective effects of dexmedetomidine treatment were reversed by the CB₂ receptor antagonist AM630 or the PI3K inhibitor wortmannin. And the CB₂ receptor antagonist AM630 also downregulated the expression of Akt. Thus, our findings suggest that treatment with dexmedetomidine provides a protective role against lung injury caused by intestinal I/R in rats, possibly due to the upregulation of the CB₂ receptor, followed by the activation of the PI3K/Akt pathway.

Involvement of Metabolic Lipid Mediators in the Regulation of Apoptosis

Apoptosis is the physiological mechanism of cell death and can be modulated by endogenous and exogenous factors, including stress and metabolic alterations. Reactive oxygen species (ROS), as well as ROS-dependent lipid peroxidation products (including isoprostanes and reactive aldehydes including 4-hydroxynonenal) are proapoptotic factors. These mediators can activate apoptosis via mitochondrial-, receptor-, or ER stress-dependent pathways. Phospholipid metabolism is also an essential regulator of apoptosis, producing the proapoptotic prostaglandins of the PGD and PGJ series, as well as the antiapoptotic prostaglandins of the PGE series, but also 12-HETE and 20-HETE. The effect of endocannabinoids and phytocannabinoids on apoptosis depends on cell type-specific differences. Cells where cannabinoid receptor type 1 (CB1) is the dominant cannabinoid receptor, as well as cells with high cyclooxygenase (COX) activity, undergo apoptosis after the administration of cannabinoids. In contrast, in cells where CB2 receptors dominate, and cells with low COX activity, cannabinoids act in a cytoprotective manner. Therefore, cell type-specific differences in the pro- and antiapoptotic effects of lipids and their (oxidative) products might reveal new options for differential bioanalysis between normal, functional, and degenerating or malignant cells, and better integrative biomedical treatments of major stress-associated diseases.

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.

The effect of high maternal linoleic acid on endocannabinoid signalling in rodent hearts

The endocannabinoid system (ECS), modulated by metabolites of linoleic acid (LA), is important in regulating cardiovascular function. In pregnancy, LA is vital for foetal development. We investigated the effects of elevated LA in H9c2 cardiomyoblasts in vitro and of a high linoleic acid (HLA, 6.21%) or low linoleic acid (LLA, 1.44%) diet during pregnancy in maternal and offspring hearts. H9c2 cell viability was reduced following LA exposure at concentrations between 300 and 1000 µM. HLA diet decreased cannabinoid receptor type 2 (CB2) mRNA expression in foetal hearts from both sexes. However, HLA diet increased CB2 expression in maternal hearts. The mRNA expression of fatty acid amide hydrolase (FAAH) in foetal hearts was higher in females than in males irrespective of diet and N-acyl phosphatidylethanolamine-specific phospholipase D (NAPE-PLD) mRNA expression showed an interaction between diet and sex. Data indicate that a high LA diet alters cell viability and CB2 expression, potentially influencing cardiac function during pregnancy and development of the offspring's heart.

Propofol Induces Cardioprotection Against Ischemia-Reperfusion Injury via Suppression of Transient Receptor Potential Vanilloid 4 Channel

Ca²⁺ entry via the transient receptor potential vanilloid 4 (TRPV4) channel contributes to Ca²⁺ overload and triggers many pathophysiological conditions, including myocardial ischemia/reperfusion (I/R) injury. Propofol, a widely used intravenous anesthetic, attenuates myocardial I/R injury. However, the mechanism of propofol remains to be examined. The present study aims to test the hypothesis that propofol attenuates myocardial I/R injury through the suppression of TRPV4. We used a murine ex vivo model of myocardial I/R and in vitro cultured myocytes subjected to hypoxia/reoxygenation (H/R). Propofol or TRPV4 antagonist, HC-067047, attenuates myocardial I/R injury in isolated hearts. In addition, propofol, HC-067047, or TRPV4-siRNA attenuates H/R-induced intracellular Ca²⁺ concentration ([Ca²⁺]_i) increase and cell viability reduction. On the contrary, TRPV4 agonist GSK1016790A exacerbates both ex vivo and in vitro myocardial injury. Pretreatment with propofol reverses the myocardial injury and intracellular Ca²⁺ overload induced by GSK1016790A at least in vitro. However, neither the combination of propofol and HC-067047 nor applying propofol to cells transfected with TRPV4-siRNA creates additional protective effects. In addition, propofol dose-dependently inhibits TRPV4-mediated Ca²⁺ entry induced by GSK1016790A and 4α-PDD. Propofol attenuates myocardial I/R injury partially through the suppression of TRPV4 channel and the subsequent inhibition of intracellular Ca²⁺ overload.

PRR34-AS1 overexpression promotes protection of propofol pretreatment against ischemia/reperfusion injury in a mouse model after total knee arthroplasty via blockade of the JAK1-dependent JAK-STAT signaling pathway

Long noncoding RNAs have been documented to be protective against ischemia/reperfusion (I/R) injury. However, few research works have focused on the protective effects of PRR34-AS1 on I/R injury after total knee arthroplasty (TKA). The objective of the present study was to investigate the possible effect of PRR34-AS1 on I/R injury after TKA. A mouse model with I/R injury after TKA was established. The interaction between PRR34-AS1 and Janus kinase 1 (JAK1) was examined and thoroughly investigated. Next, the effects of PRR34-AS1 on the expression of apoptosis-related proteins, JAS-signal transducer and activator of transcription (STAT) signaling pathways, and inflammation-related genes, chondrocyte proliferation, and apoptosis were analyzed after gain- and loss-of-function experiments. Attenuated symptoms were observed in mice pretreated with propofol, which was evidenced by decreased positive expression rate of JAK1 protein and superoxide dismutase content along with increased malondialdehyde content and IL-10 levels. PRR34-AS1 was poorly expressed in mice with I/R injury after TKA. JAK1 was a target of PRR34-AS1. Upregulated PRR34-AS1 diminished expression of JAK1, STAT1, JAK2, and STAT3 as well as cell apoptosis, while enhancing cell proliferation in vitro. Furthermore, JAK1 silencing could reverse the suppressed cell proliferation and enhanced cell apoptosis of chondrocytes imposed by silencing PRR34-AS1. Upregulation of PRR34-AS1 can potentially relieve I/R injury after TKA in mice pretreated with propofol through inhibition of the JAS-STAT signaling pathway by targeting JAK1.

A standardized rat burr hole defect model to study maxillofacial bone regeneration

With high incidence rate and unique regeneration features, maxillofacial burr hole bone defects require a specially designed bone defect animal model for the evaluation of related bone regenerative approaches. Although some burr hole defect models have been developed in long bones or calvarial bones, the mandible has unique tissue development origins and regenerative environments. This suggests that the defect model should be prepared in the maxillofacial bone area. After dissecting the anatomic structures of rat mandibles, we found that creating defects in the anterior tooth area avoided damaging important organs and improved animal welfare. Furthermore, the available bone volume at the anterior tooth area was superior to that of the posterior tooth and ascending ramus areas. We then managed to standardize the model by controlling the age, weight and gender of the animal, creating standardized measurement instruments and reducing the variations derived from various operators. We also succeeded in deterring the self-rehabilitation of the proposed model by increasing the defect size. The 6 × 2 mm and 8 × 2 mm defects were found to meet the requirements of bone regenerative studies. This study provided a step-by-step standardized burr hole bone defect model with minimal tissue damage in small animals. The evaluations resulting from this model testify to the in vitro outcomes of the proposed regenerative approaches and provide preliminary screening data for further large animal and clinical trials. Therefore, the inclusion of this model may optimize the evaluation systems for maxillofacial burr hole bone defect regenerative approaches. STATEMENT OF SIGNIFICANCE: Unremitting effort has been devoted to the development of bone regenerative materials to restore maxillofacial burr hole bone defects because of their high clinical incidence rate. In the development of these biomaterials, in vivo testing in small animals is necessary to evaluate the effects of candidate biomaterials. However, little has been done to develop such defect models in small animals. In this study, we developed a standardized rat mandible burr hole bone defect model with minimal injury to the animals. A detailed description and supplementary video were provided to guide the preparation. The development of this model optimizes the maxillofacial bone regenerative approach evaluation system.

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.

Modulation of the Oxidative Stress and Lipid Peroxidation by Endocannabinoids and Their Lipid Analogues

Growing evidence supports the pivotal role played by oxidative stress in tissue injury development, thus resulting in several pathologies including cardiovascular, renal, neuropsychiatric, and neurodegenerative disorders, all characterized by an altered oxidative status. Reactive oxygen and nitrogen species and lipid peroxidation-derived reactive aldehydes including acrolein, malondialdehyde, and 4-hydroxy-2-nonenal, among others, are the main responsible for cellular and tissue damages occurring in redox-dependent processes. In this scenario, a link between the endocannabinoid system (ECS) and redox homeostasis impairment appears to be crucial. Anandamide and 2-arachidonoylglycerol, the best characterized endocannabinoids, are able to modulate the activity of several antioxidant enzymes through targeting the cannabinoid receptors type 1 and 2 as well as additional receptors such as the transient receptor potential vanilloid 1, the peroxisome proliferator-activated receptor alpha, and the orphan G protein-coupled receptors 18 and 55. Moreover, the endocannabinoids lipid analogues N-acylethanolamines showed to protect cell damage and death from reactive aldehydes-induced oxidative stress by restoring the intracellular oxidants-antioxidants balance. In this review, we will provide a better understanding of the main mechanisms triggered by the cross-talk between the oxidative stress and the ECS, focusing also on the enzymatic and non-enzymatic antioxidants as scavengers of reactive aldehydes and their toxic bioactive adducts.

Anandamide and endocannabinoid system: an attractive therapeutic approach for cardiovascular disease

Cardiovascular disease is currently not adequately managed and has become one of the main causes of morbidity and mortality worldwide. Current therapies are inadequate in terms of preventing its progression. There are several limitations, such as poor oral bioavailability, side effects, low adherence to treatment, and high dosage frequency of formulations due to the short half-life of the active ingredients used, among others. This review aims to highlight the most relevant aspects of the relationship between the cardiovascular system and the endocannabinoid system, with special attention to the possible translational effect of the use of anandamide in cardiovascular health. The deep and detailed knowledge of this interaction, not always beneficial, and that for years has gone unnoticed, is essential for the development of new therapies. We discuss the most recent and representative results obtained in the field of basic research, referring to the aforementioned subject, emphasizing fundamentally the main role of nitric oxide, renal physiology and its deregulation in pathological processes.