Cross-Talk between the (Endo)Cannabinoid and Renin-Angiotensin Systems: Basic Evidence and Potential Therapeutic Significance

Angiotensin 1-7 injected into the rat paraventricular nucleus of hypothalamus increases blood pressure and heart rate via various receptors

Although angiotensin 1-7 (Ang 1-7) and its role as a part of the "protective" axis of the renin-angiotensin system are well described in the literature, the mechanisms of its angiotensin II-like pressor and tachycardic effects following its acute central administration are not fully understood. It was the aim of the present study to examine which receptors contribute to the aforementioned cardiovascular effects. Ang 1-7 and antagonists for glutamate, GABA, vasopressin, thromboxane A2 (TP), α1-adrenergic, and P2X purinoceptors or modulators of oxidative stress were injected into the paraventricular nucleus of the hypothalamus (PVN) of urethane-anesthetized male Wistar rats. Acute injection of Ang 1-7 into the PVN increased blood pressure (BP) by about 15 mmHg and heart rate (HR) by about 14 beats/min. After preinjection with bicuculline (GABAA receptor antagonist), CNQX + D-AP5 (AMPA/kainate and NMDA receptor antagonists) and SQ29548 (TP receptor antagonist) the BP and HR reactions to Ang 1-7 were attenuated or abolished. The vasopressin V1A and V1B receptor antagonists conivaptan and nelivaptan, and the NADPH oxidase inhibitor apocynin even reversed the pressor and tachycardic effects of Ang 1-7. Antagonists of P2X (PPADS) and α1-adrenergic receptors (prazosin), the free radical scavenger tempol and the superoxide dismutase inhibitor DETC did not modify the cardiovascular effects of Ang 1-7. The (Mas receptor-related) rise in BP and HR evoked by Ang 1-7 administered to the rat PVN is linked to glutamate, vasopressin, GABAA and thromboxane receptors, and to oxidative stress, but does not seem to involve α1-adrenergic or P2X receptors.

Chronic cannabidiol treatment induces cardiovascular improvement in renovascular hypertensive rats

BACKGROUND

Cannabidiol (CBD) is increasingly studied for its therapeutic potential in neurodegenerative diseases. Previous research on acute CBD administration has demonstrated cardiovascular benefits in hypertensive rats, including reduced mean blood pressure and oxidative stress.

AIM

To investigate the long-term cardiovascular effects of chronic CBD treatment in renovascular hypertension induced by the 2-kidney-1-clip (2K1C) model.

METHODS

Male Wistar rats (180-200 g, 8 weeks old) underwent 2K1C or SHAM surgery. Six weeks later, rats received chronic CBD treatment (20 mg/kg, twice daily for 14 days). A combination of ex vivo, in vitro, and in vivo methods was used to assess CBD's cardiovascular effects in 2K1C hypertensive rats.

RESULTS

Chronic CBD treatment significantly reduced blood pressure and the depressor response to hexamethonium (a ganglionic blocker). It also normalized variability in low-frequency (LF) power and LF/high-frequency (HF) ratio. CBD enhanced vasodilation and reduced vasoconstriction in the mesenteric artery of 2K1C rats, accompanied by decreased expression of aortic reactive oxygen species (ROS).

CONCLUSION

Our findings suggest that chronic CBD treatment exerts antihypertensive effects by improving baroreflex sensitivity and vascular function while decreasing arterial ROS levels and sympathetic nerve activity. These results underscore CBD's potential therapeutic role in managing cardiovascular complications associated with renovascular hypertension.

Cannabis use associated with lower mortality among hospitalized Covid-19 patients using the national inpatient sample: an epidemiological study

BACKGROUND

Prior reports indicate that modulation of the endocannabinoid system (ECS) may have a protective benefit for Covid-19 patients. However, associations between cannabis use (CU) or CU not in remission (active cannabis use (ACU)), and Covid-19-related outcomes among hospitalized patients is unknown.

METHODS

In this multicenter retrospective observational cohort analysis of adults (≥ 18 years-old) identified from 2020 National Inpatient Sample database, we utilize multivariable regression analyses and propensity score matching analysis (PSM) to analyze trends and outcomes among Covid-19-related hospitalizations with CU and without CU (N-CU) for primary outcome of interest: Covid-19-related mortality; and secondary outcomes: Covid-19-related hospitalization, mechanical ventilation (MV), and acute pulmonary embolism (PE) compared to all-cause admissions; for CU vs N-CU; and for ACU vs N-ACU.

RESULTS

There were 1,698,560 Covid-19-related hospitalizations which were associated with higher mortality (13.44% vs 2.53%, p ≤ 0.001) and worse secondary outcomes generally. Among all-cause hospitalizations, 1.56% of CU and 6.29% of N-CU were hospitalized with Covid-19 (p ≤ 0.001). ACU was associated with lower odds of MV, PE, and death among the Covid-19 population. On PSM, ACU(N(unweighted) = 2,382) was associated with 83.97% lower odds of death compared to others(N(unweighted) = 282,085) (2.77% vs 3.95%, respectively; aOR:0.16, [0.10-0.25], p ≤ 0.001).

CONCLUSIONS

These findings suggest that the ECS may represent a viable target for modulation of Covid-19. Additional studies are needed to further explore these findings.

Melatonin as a Chronobiotic and Cytoprotector in Non-communicable Diseases: More than an Antioxidant

A circadian disruption, manifested by disturbed sleep and low-grade inflammation, is commonly seen in noncommunicable diseases (NCDs). Cardiovascular, respiratory and renal disorders, diabetes and the metabolic syndrome, cancer, and neurodegenerative diseases are among the most common NCDs prevalent in today's 24-h/7 days Society. The decline in plasma melatonin, which is a conserved phylogenetic molecule across all known aerobic creatures, is a constant feature in NCDs. The daily evening melatonin surge synchronizes both the central pacemaker located in the hypothalamic suprachiasmatic nuclei (SCN) and myriads of cellular clocks in the periphery ("chronobiotic effect"). Melatonin is the prototypical endogenous chronobiotic agent. Several meta-analyses and consensus studies support the use of melatonin to treat sleep/wake cycle disturbances associated with NCDs. Melatonin also has cytoprotective properties, acting primarily not only as an antioxidant by buffering free radicals, but also by regulating inflammation, down-regulating pro-inflammatory cytokines, suppressing low-grade inflammation, and preventing insulin resistance, among other effects. Melatonin's phylogenetic conservation is explained by its versatility of effects. In animal models of NCDs, melatonin treatment prevents a wide range of low-inflammation-linked alterations. As a result, the therapeutic efficacy of melatonin as a chronobiotic/cytoprotective drug has been proposed. Sirtuins 1 and 3 are at the heart of melatonin's chronobiotic and cytoprotective function, acting as accessory components or downstream elements of circadian oscillators and exhibiting properties such as mitochondrial protection. Allometric calculations based on animal research show that melatonin's cytoprotective benefits may require high doses in humans (in the 100 mg/day range). If melatonin is expected to improve health in NCDs, the low doses currently used in clinical trials (i.e., 2-10 mg) are unlikely to be beneficial. Multicentre double-blind studies are required to determine the potential utility of melatonin in health promotion. Moreover, melatonin dosage and levels used should be re-evaluated based on preclinical research information.

Why Multitarget Vasodilatory (Endo)cannabinoids are Not Effective as Antihypertensive Compounds after Chronic Administration: Comparison of Their Effects on Systemic and Pulmonary Hypertension

Systemic and pulmonary hypertension are multifactorial, high-pressure diseases. The first one is a civilizational condition, and the second one is characterized by a very high mortality rate. Searching for new therapeutic strategies is still an important task. (Endo)cannabinoids, known for their strong vasodilatory properties, have been proposed as possible drugs for different types of hypertension. Unfortunately, our review, in which we summarized all publications found in the PubMed database regarding chronic administration of (endo)cannabinoids in experimental models of systemic and pulmonary hypertension, does not confirm any encouraging suggestions, being based mainly on in vitro and acute in vivo experiments. We considered vasodilator or blood pressure (BP) responses and cardioprotective, anti-oxidative, and the anti-inflammatory effects of particular compounds and their influence on the endocannabinoid system. We found that multitarget (endo)cannabinoids failed to modify higher BP in systemic hypertension since they induced responses leading to decreased and increased BP. In contrast, multitarget cannabidiol and monotarget ligands effectively treated pulmonary and systemic hypertension, respectively. To summarize, based on the available literature, only (endo)cannabinoids with a defined site of action are recommended as potential antihypertensive compounds in systemic hypertension, whereas both mono- and multitarget compounds may be effective in pulmonary hypertension.