Central nervous system, peripheral and hemodynamic effects of nanoformulated anandamide in hypertension

PURPOSE

Hypertensive lesions induce alterations at hemodynamic, peripheral, and central levels. Anandamide (N-arachidonoylethanolamine; AEA) protects neurons from inflammatory damage, but its free administration may cause central adverse effects. AEA controlled release by nanoformulations could reduce/eliminate its side effects. The present study aimed to evaluate the effects of nanoformulated AEA (nf-AEA) on systolic blood pressure (SBP), behavior, and central/peripheral inflammatory, oxidative, and apoptotic state in spontaneously hypertensive rats (SHR).

MATERIALS/METHODS

Male rats were used, both Wistar Kyoto (WKY) and SHR (n ​= ​10 per group), with/without treatment with nf-AEA (obtained by electrospraying) at a weekly dose of 5 ​mg/kg IP for 4 weeks. SBP was measured and behavioral tests were performed. Inflammatory/oxidative markers were quantified at the central (brain cortex) and peripheral (serum) level.

RESULTS

SHR showed hyperactivity, low anxiety, and high concentrations of central/peripheral inflammatory/oxidative markers, also higher apoptosis of brain cortical cells compared to WKY. As opposed to this group, treatment with nf-AEA in SHR significantly reduced SBP, peripheral/central inflammatory/oxidative makers, and central apoptosis. Nf-AEA also increased neuroprotective mechanisms mediated by intracellular heat shock protein 70 (Hsp70), which were attenuated in untreated SHR. Additionally, nf-AEA reversed the abnormal behaviors observed in SHR without producing central adverse effects.

CONCLUSIONS

Our results suggest protective properties of nf-AEA, both peripherally and centrally, through a signaling pathway that would involve the type I angiotensin II receptor, Wilms tumor transcription factor 1, Hsp70, and iNOS. Considering non-nf-AEA limitations, this nanoformulation could contribute to the development of new antihypertensive and behavioral disorder treatments associated with neuroinflammation.

Sexual interaction is essential for the transformation of non-copulating rats into sexually active animals by the endocannabinoid anandamide

The endocannabinoid anandamide (AEA) transforms half of the population of previously non-copulating (NC) rats into sexually active animals in a long-lasting manner. The aim of this work was to explore the nature of this transformation. We identified the dose range in which AEA induces mating behavior in previously NC rats, which evidenced a dose-based, biphasic profile for AEA to induce the transformation of NC rats. We demonstrate that the sexual interaction with a receptive female, involving at least an intromission, is essential for AEA to induce the transformation of NC rats. This AEA-induced conversion is centrally mediated and involves the activation of CB1 receptors. Results indicate that the sexual impairment of this population of NC rats relies on their incapacity to initiate sexual activity and that an unidentified brain inhibitory influence on sexual behavior expression is removed by AEA treatment, allowing previously NC rats to show copulatory behavior in a long-lasting manner. The inhibitory influence is not removed by AEA treatment when animals are not allowed to have sexual contact with the female immediately after AEA injection. The same result was found for the opioid receptor antagonist naloxone, the other treatment reported to induce copulation in rats classified as NC. These data suggest that sexual behavior expression could depend on two different neural mechanisms at two different moments: one involved in the display of the first copulatory response and another responsible for maintaining subsequent sexual behavior responding.

Orexin-A and endocannabinoid signaling regulate glucose-responsive arcuate nucleus neurons and feeding behavior in obese rats

Obesity is a global public health problem. Orexin and endocannabinoid signaling in the hypothalamus have been shown to regulate feeding and are promising molecular targets for obesity treatment. In this study, we attempted to analyze effects of orexin-A and endocannabinoid signaling modulation in the arcuate nucleus (Arc) on feeding and glucose-responsive (GR) neurons physiology in a diet-induced obesity (DIO) and diet-induced obesity resistant (DR) rat model. Administration of orexin-A or cannabinoid receptor type-1 (CB₁R) antagonist AM251 altered the firing of GR neurons in the Arc. The effects of orexin-A were eliminated by pre-administrating orexin-1 receptor (OX-1R) antagonist SB334867, respectively. Behavioral studies showed that orexin-A increased food intake, while AM251 reduced feeding. Histological studies showed that mRNA and protein expression of OX-1R (orexin-1 receptor) and CB₁R were increased in the Arc of DIO and DR rats. Our results strongly suggest that orexin-A and endocannabinoid signaling in Arc plays an important role in regulating GR neuronal excitability and food intake in obesity.

The role of exercise training and the endocannabinoid system in atherosclerotic plaque burden and composition in Apo-E-deficient mice

INTRODUCTION

We investigated the effect of combining exercise training and treatment with an endocannabinoid receptor 1 inhibitor (Rimonabant) on atherosclerosis burden and composition.

METHODS

Forty-eight apolipoprotein E-deficient (ApoE-/-) mice were kept on a 16-week high-fat diet. Mice were then placed on a normal diet and were randomized to the following groups with n=12 mice for 6 more weeks: 1) Control (Co) - no intervention; 2) Exercise (Ex) - exercise training on treadmill; 3) Rimonabant (Ri) - oral administration of rimonabant (10 mg/kg/day); or 4) Rimonabant+Exercise (RiEx) - combination of Ri and Ex groups treatment. At the end, all animals were sacrificed, and blood samples, as well as aortic root specimens, were obtained for histomorphometric analysis and quantification of the serum and plaque content of matrix metalloproteinases (MMPs).

RESULTS

The mean plaque area was significantly smaller (RiEx: 43.18±1.72%, Ri: 44.66±3.1%, Ex: 49±4.10%, Co: 70.43±2.83%) in all active treatment groups relative to the Co group (p<0.01). Conversely, the relative concentrations of collagen and elastin were increased significantly across all treatment groups compared to Co (p<0.05). Immunohistochemical analysis revealed significantly reduced macrophage content within plaques after all interventions, with the most pronounced effect observed after combined treatment (RiEx: 9.4±3.92%, Ri: 15±2.45%, Ex: 19.78±2.79%, Co: 34.25±4.99%; p<0.05). Within plaques, the TIMP-1 concentration was significantly upregulated in exercise-treated groups. MMP-3 and MMP-9 concentrations were equivalently decreased in all three active treatment groups compared to controls (p<0.001).

DISCUSSION

Both exercise and rimonabant treatments induced plaque regression and promoted plaque stability. The combined treatment failed to show additive or synergistic benefits relative to either intervention alone.

Anandamide interferes with human endometrial stromal-derived cell differentiation: An effect dependent on inhibition of cyclooxygenase-2 expression and prostaglandin E2 release

The human endometrium undergoes cyclical growth, differentiation, and regression periods throughout the reproductive life. The process in which endometrial stromal cells proliferate and differentiate into decidual cells, named decidualization, prepares a receptive endometrium for implantation. Prostaglandins (PGs) and endocannabinoids (eCBs) are crucial mediators of this process. We have recently reported that the eCB anandamide (AEA) interferes with rat stromal cell differentiation, and on the other hand, PGs are also crucial for decidualization. Therefore, in this study, we analyzed the AEA levels, both in nondifferentiated and in decidualizing human endometrial stromal cells by liquid chromatography-mass spectrometry, and investigated the impact of AEA on PG release and cyclooxygenase-2 (COX-2) expression in human endometrial stromal-derived cell differentiation. For that, an ultra-performance liquid chromatography-mass spectrometry/mass spectrometry method to measure prostaglandin E2 (PGE2 ) and prostaglandin F2α in biological samples was developed and validated. We demonstrate that AEA levels in decidualizing cells are lower than those in nondifferentiated cells, whereas PGE2 levels and COX-2 expression are up-regulated. Thus, low AEA levels may be essential for the onset of decidualization. On the contrary, in AEA-treated cells undergoing decidualization, a decrease of COX-2 protein levels and PGE2 production, in a manner dependent on cannabinoid receptor 1 activation, was observed. Overall, these findings suggest that a deregulation of the intricate network that drives cell differentiation may compromise pregnancy and fertility. It is clinically relevant to understand the mechanisms that influence eCB and PG levels in the endometrium because they may shed light on the sequence of events that lead to a successful pregnancy. © 2016 BioFactors, 42(3):277-286, 2016.

The effects of endocannabinoid receptor agonist anandamide and antagonist rimonabant on opioid analgesia and tolerance in rats

The role of the cannabinoid (CB) system in the tolerance to analgesic effect of opioid remains obscure. The aim of the present study was to evaluate the effects of the endocannabinoid nonselective receptor agonist anandamide (AEA) and CB1 receptor antagonist rimonabant (SR141716) on morphine analgesia and tolerance in rats. Male Wistar albino rats weighing 215-230 g were used in these experiments. To constitute morphine analgesic tolerance, a 3-day cumulative dosing regimen was used. The analgesic effects of AEA (10 mg/kg), SR141716 (10 mg/kg), and morphine (5 mg/kg) were considered at 30-min intervals by tail flick (TF) and hot plate (HP) analgesia tests. The analgesic effects of the drugs were measured as TF and HP latencies in all groups for each rat and converted to %MPE. The data were analysed by analysis of variance followed by Tukey test. The findings suggested that AEA in combination with morphine produced a significant increase in expression of analgesic tolerance to morphine. Conversely, cannabinoid receptor antagonist SR141716 attenuated morphine analgesic tolerance. In addition, administration of AEA with morphine increased morphine analgesia. In conclusion, we observed that the cannabinoid receptor agonist anandamide and CB1 receptor antagonist SR141716 plays a significant role in the opioid analgesia and tolerance.

[Administration of micronized palmitoylethanolamide (PEA)-transpolydatin in the treatment of chronic pelvic pain in women affected by endometriosis: preliminary results]

AIM

Aim of the study was to evaluate the effectiveness of micronized palmitoylethanolamide (PEA)-transpolydatin in the treatment of chronic pelvic pain in women affected by endometriosis.

METHODS

Twenty-four patients with suspected endometriosis affected by severe pelvic pain were enrolled. All patients received two tablets a day of PEA 400 mg and 40 mg polydatin for 90 days consecutively. A Visual Analogic Scale was used for the assessment of the severity of global pain, dysmenorrhea, dyspareunia, dysuria and dischezia. A second questionnaire was submitted to patients to assess the quality of life. The compilation of a diary lead us to evaluate the monthly assumption of any painkillers. Patients were evaluated at the begin of the treatment and then monthly until the end of the study (90 days). The statistical analysis was performed by using the ANOVA for the analysis of variance.

RESULTS

Statistically significant results were found in relation to pelvic pain, dysmenorrhea and dyspareunia compared to the initial evaluation of patients. Results related to dysuria and dischezia were not statistically significant (P>0.05). The decrease in pelvic pain leads to an improvement of the quality of life of patients. A decreased assumption of nonsteroidal anti-inflammatory drugs (NSAIDs) was also observed.

CONCLUSION

PEA could be considered an effective supplement to conventional analgesic therapies in the management of pelvic pain related to endometriosis.

Reduction of ischemic brain injury by administration of palmitoylethanolamide after transient middle cerebral artery occlusion in rats

Stroke is the third leading cause of death and the leading cause of long-term disability in adults. Current therapeutic strategies for stroke, including thrombolytic drugs, such as tissue plasminogen activator offer great promise for the treatment, but complimentary neuroprotective treatments are likely to provide a better outcome. To counteract the ischemic brain injury in mice, a new therapeutic approach has been employed by using palmitoylethanolamide (PEA). PEA is one of the members of N-acyl-ethanolamine family maintain not only redox balance but also inhibit the mechanisms of secondary injury on ischemic brain injury. Treatment of the middle cerebral artery occlusion (MCAo)-induced animals with PEA reduced edema and brain infractions as evidenced by decreased 2,3,5-triphenyltetrazolium chloride (TTC) staining across brain sections. PEA-mediated improvements in tissues histology shown by reduction of lesion size and improvement in apoptosis level (assayed by Bax and Bcl-2) further support the efficacy of PEA therapy. We demonstrated that PEA treatment blocked infiltration of astrocytes and restored MCAo-mediated reduced expression of PAR, nitrotyrosine, iNOS, chymase, tryptase, growth factors (BDNF and GDNF) and GFAP. PEA also inhibited the MCAo-mediated increased expression of pJNK, NF-κB, and degradation of IκB-α. PEA-treated injured animals improved neurobehavioral functions as evaluated by motor deficits. Based on these findings we propose that PEA would be useful in lowering the risk of damage or improving function in ischemia-reperfusion brain injury-related disorders.