Pharmacological evidence for connection of nitric oxide-mediated pathways in neuroprotective mechanism of ischemic postconditioning in mice

Neuroprotective Effect of Piclamilast-Induced Post-Ischemia Pharmacological Treatment in Mice

Various studies have evidenced the neuroprotective role of PDE4 inhibitors. However, whether PDE4 inhibitor, Piclamilast pharmacological post-treatment is protective during cerebral ischemia reperfusion-induced injury remains unknown. Therefore, this study design included testing the hypothesis that Piclamilast administered at the beginning of a reperfusion phase (Piclamilast pPost-trt) shows protective effects and explores & probes underlying downstream mechanisms. Swiss albino male mice were subjected to global ischemic and reperfusion injury for 17 min. The animals examined cerebral infarct size, biochemical parameters, inflammatory mediators, and motor coordination. For memory, assessment mice were subjected to morris water maze (MWM) and elevated plus maze (EPM) test. Histological changes were assessed using HE staining. Piclamilast pPost-trt significantly reduced I/R injury-induced deleterious effects on biochemical parameters of oxidative stress, inflammatory parameters, infarct size, and histopathological changes, according to the findings. These neuroprotective effects of pPost-trt are significantly abolished by pre-treatment with selective CREB inhibitor, 666-15. Current study concluded that induced neuroprotective benefits of Piclamilast Post-trt, in all probability, maybe mediated through CREB activation. Hence, its neuroprotective effects can be further explored in clinical settings.

Pre- and Post-Conditioning of the Heart: An Overview of Cardioprotective Signaling Pathways

Since the discovery of ischemic pre- and post-conditioning, more than 30 years ago, the knowledge about the mechanisms and signaling pathways involved in these processes has significantly increased. In clinical practice, on the other hand, such advancement has yet to be seen. This article provides an overview of ischemic pre-, post-, remote, and pharmacological conditioning related to the heart. In addition, we reviewed the cardioprotective signaling pathways and therapeutic agents involved in the above-mentioned processes, aiming to provide a comprehensive evaluation of the advancements in the field. The advancements made over the last decades cannot be ignored and with the exponential growth in techniques and applications. The future of pre- and post-conditioning is promising.

Prophylaxis with a multicomponent nutraceutical abates transient cerebral ischemia/reperfusion injury

The effect of a multicomponent nutraceutical on cerebral ischemia/reperfusion injury in male Wistar rats was investigated. Animals were administered with the nutraceutical, Trévo™, for 7 days before 30 min of bilateral common carotid artery occlusion-induced cerebral ischemia and 24 hr of reperfusion. Behavioral assessment, biochemical estimations in the brain cortex, striatum, and hippocampus, and hippocampal histopathological evaluation were carried out after treatments. Results showed that ischemia/reperfusion-induced motor and cognitive deficits were abated in rats pretreated with Trévo™. Additionally, prophylaxis with Trévo™ blunted ischemia/reperfusion-induced redox stress, proinflammatory events, disturbances in neurotransmitter metabolism, mitochondrial dysfunction, and histoarchitectural aberrations in the discreet brain regions. In summary, supplementation with Trévo™ provided neuroprotection to rats against transient cerebral ischemia/reperfusion injury and could be explored as a promising approach in stroke prevention. PRACTICAL APPLICATIONS: There is a worldwide increase in the incidence of cerebral ischemia or stroke. Although an advanced health care system and effective control of risk factors have led to the declining incidence in developed nations, a definitive cure for stroke remains elusive and the situation is growing worse in developing nations. The results of the present study revealed that supplementation with Trévo™ ameliorated neurobehavioral, neurochemical, and histopathological consequences of brain ischemia/reperfusion injury and could, therefore, be beneficial in stroke prevention and management.

Investigation on beneficial role of l-carnosine in neuroprotective mechanism of ischemic postconditioning in mice: possible role of histidine histamine pathway

OBJECTIVE

The present study was undertaken to investigate the possible role of histidine-histamine pathway in the neuroprotective effects produced by L-carnosine hand in hand with ischemic postconditioning in the animal model of cerebral ischemia.

METHODS

Cerebral ischemia was induced in swiss albino mice by performing BCCAO surgery. Morris water-maze test was utilized to assess the learning ability and memory of the animals. The whole brain acetylcholinesterase (AChE) activity, TBARS, GSH levels and MPO activity were evaluated as the biochemical parameters. For histopathological evaluation of the cerebral infarct size, TTC staining was employed.

RESULTS

Administration of L-carnosine (500   mg/kg, i.p.) successfully attenuated the manifestations of cerebral ischemia. Higher levels of AChE, TBARS, and MPO were observed in BCCAO treated animals, which were successfully attenuated by treatment with L-carnosine and ischemic postconditioning. Whereas administration of L-carnosine and ischemic postconditioning significantly increased the level of GSH in BCCAO treated animals. Moreover, treatment with ranitidine, an H₂ blocker (30 NMol, i.c.v) antagonized the neuroprotective actions of L-carnosine evidenced by decrease in MWM performance, increase in the level of AChE and oxidative stress, while decrease in GSH level in brain. The cerebral infarct size was found to be more in BCCAO inflicted animals, which was improved by the administration of L-carnosine, while the cerebral infarct size worsened by treatment with ranitidine (3   nmol, i.c.v.).

CONCLUSION

It is concluded that L-carnosine exerts neuroprotective effect via involvement of histidine-histamine pathway since the beneficial effects of L-carnosine were abolished by the H₂-blocker.

Effects of resveratrol postconditioning on cerebral ischemia in mice: role of the sirtuin-1 pathway

Evidence has demonstrated that resveratrol preconditioning exhibits neuroprotection against cerebral ischemia-reperfusion (IR) injury. The current investigation aimed to explore whether pharmacological postconditioning, by administering resveratrol, after a sustained ischemia and prior to prolonged reperfusion abrogates cerebral IR injury. Cerebral IR-induced injury mice model was employed in this study to evaluate the neuroprotective effects of pharmacological postconditioning with resveratrol (30 mg/kg; i.p.) administered 5 min before reperfusion. We administered sirtinol, a SIRT1/2 selective inhibitor (10 mg/kg; i.p.) 10 min before ischemia (17 min) and reperfusion (24 h), to elucidate whether the neuroprotection with resveratrol postconditioning depends on SIRT1 activation. Various biochemical and behavioural parameters and histopathological changes were assessed to examine the effect of pharmacological postconditioning. Infarct size is estimated using TTC staining. It was established that resveratrol postconditioning abrogated the deleterious effects of IR injury expressed with regard to biochemical parameters of oxidative stress (TBARS, SOD, GSH), acetylcholinesterase activity, behavioural parameters (memory, motor coordination), infarct size, and histopathological changes. Sirtinol significantly reversed the effect of resveratrol postconditioning. We conclude that induced neuroprotective benefits of resveratrol postconditioning may be the consequence of SIRT1 activation and resveratrol can be considered, for further studies, as potential agent inducing pharmacological postconditioning in clinical situations.

Neuroprotective effect of pharmacological postconditioning on cerebral ischaemia-reperfusion-induced injury in mice

OBJECTIVES

To investigate the mechanism of neuroprotection rendered via pharmacological postconditioning in cerebral ischaemia-reperfusion-induced injury in mice.

METHODS

Pharmacological postconditioning is strategy which either involves hindering deleterious pathway or inducing modest stress level which triggers intracellular defence pathway to sustain more vigorous insult leading to conditioning. Hence, in current research we explored the potentiality of CGS21680 (0.5 mg/kg; i.p), an adenosine A₂ A receptor agonist and PTEN inhibitor, SF1670 (3 mg/kg; i.p.) to trigger postconditioning after inducing cerebral global ischaemia (17 min) and reperfusion (24 h)-induced injury via occlusion of both carotid arteries. Mice were also given treatment with LY294002 (1.5 mg/kg; i.p.), a PI3K inhibitor and adenosine A₂ A receptor antagonist, Istradefylline (2 mg/kg; i.p.), to establish the precise mechanism of postconditioning. Various biochemical and behavioural parameters were assessed to examine the effect of pharmacological postconditioning.

KEY FINDINGS

Pharmacological postconditioning induced with CGS21680 and SF1670 attenuated the infarction along with improved behavioural and biochemical parameters in comparison with ischaemia-reperfusion control group. The outcome of postconditioning with CGS21680 and SF1670 was significantly reversed by LY294002 and Istradefylline, respectively.

CONCLUSIONS

The neuroprotective effects of CGS21680 and SF1670 postconditioning on cerebral ischaemia-reperfusion injury may be due to PI3K/Akt pathway activation.

Overview of Experimental and Clinical Findings regarding the Neuroprotective Effects of Cerebral Ischemic Postconditioning

Research on attenuating the structural and functional deficits observed following ischemia-reperfusion has become increasingly focused on the therapeutic potential of ischemic postconditioning. In recent years, various methods and animal models of ischemic postconditioning have been utilized. The results of these numerous studies have indicated that the mechanisms underlying the neuroprotective effects of ischemic postconditioning may involve reductions in the generation of free radicals and inhibition of calcium overload, as well as the release of endogenous active substances, alterations in membrane channel function, and activation of protein kinases. Here we review the novel discovery, mechanism, key factors, and clinical application of ischemic postconditioning and discuss its implications for future research and problem of clinical practice.

Beyond Preconditioning: Postconditioning as an Alternative Technique in the Prevention of Liver Ischemia-Reperfusion Injury

Liver ischemia/reperfusion injury may significantly compromise hepatic postoperative function. Various hepatoprotective methods have been improvised, aiming at attenuating IR injury. With ischemic preconditioning (IPC), the liver is conditioned with a brief ischemic period followed by reperfusion, prior to sustained ischemia. Ischemic postconditioning (IPostC), consisting of intermittent sequential interruptions of blood flow in the early phase of reperfusion, seems to be a more feasible alternative than IPC, since the onset of reperfusion is more predictable. Regarding the potential mechanisms involved, it has been postulated that the slow intermittent oxygenation through controlled reperfusion decreases the burst production of oxygen free radicals, increases antioxidant activity, suppresses neutrophil accumulation, and modulates the apoptotic cascade. Additionally, favorable effects on mitochondrial ultrastructure and function, and upregulation of the cytoprotective properties of nitric oxide, leading to preservation of sinusoidal structure and maintenance of blood flow through the hepatic circulation could also underlie the protection afforded by postconditioning. Clinical studies are required to show whether biochemical and histological improvements afforded by the reperfusion/reocclusion cycles of postconditioning during early reperfusion can be translated to a substantial clinical benefit in liver resection and transplantation settings or to highlight more aspects of its molecular mechanisms.