Neuroprotective mechanisms of erythropoietin in a rat stroke model

Cardiovascular safety of current and emerging drugs to treat anaemia in chronic kidney disease: a safety review

INTRODUCTION

Erythropoiesis-stimulating agents (ESAs) are the standard of treatment for anemia in chronic kidney disease. Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHI) are small molecules that stimulate endogenous erythropoietin synthesis.

AREAS COVERED

The cardiovascular safety of ESAs and HIF-PHIs. We performed a PubMed search using several key words, including anemia, chronic kidney disease, safety, erythropoiesis stimulating agents, HIF-PH inhibitors.

EXPERT OPINION

ESAs are well-tolerated drugs with a long history of use; there are safety concerns, especially when targeting high hemoglobin levels. HIF-PHIs have comparable efficacy to ESAs in correcting anemia. Contrary to expectations, randomized phase 3 clinical trials have shown that overall HIF-PHIs were non-inferior to ESA or placebo with respect to the risk of cardiovascular endpoints. In addition, some phase 3 trials raised potential safety concerns regarding cardiovascular and thrombotic events, particularly in non-dialysis patients.Today, HIF-PHIs represent an additional treatment option for anemia in patients with chronic kidney disease. This has made the management of anemia in CKD more complex and heterogeneous. A better understanding of the mechanisms causing hypo-responsiveness to ESAs, combined with an individualized approach that balances ESAs, HIF-PHIs and iron doses, could increase the benefits while reducing the risks.

Opportunities of cerebroprotection in children in cardiac surgery (review of literature)

The analysis of the literature in the main search scientific systems was carried out to identify the current means of cerebroprotection. The assessment is given both to the familiar methods that  have become «traditional» for cardiac surgery (hypothermia, etc.) and pharmacological approaches that are less common in clinical practice: the use of melatonin,  ketamine.  The characteristics of some drugs that  are promising for solving this problem are also given.

The effects of postnatal erythropoietin and nano-erythropoietin on behavioral alterations by mediating K-Cl co-transporter 2 in the valproic acid-induced rat model of autism

In this study, based on the excitatory/inhibitory imbalance theory of autism, the time window of GABA switch, the role of K-Cl co-transporter 2 (KCC2) in adjustment GABA switch, and brain permeability to erythropoietin (EPO), the effects of postnatal -EPO and- nano- erythropoietin (NEPO) have been evaluated in the valproic acid (VPA) rat model of autism. The VPA was administered for animal modeling of autism at gestational day (GD) 12.5 (600 mg/kg). Male offsprings were injected with EPO and NEPO in a clinically proper postnatal dosing regimen on postnatal days (PND) 1-5, and autistic-like behaviors were tested at the end of the first month. Then animals were sacrificed, and neuron morphology and KCC2 expression were examined by Nissl staining and Western blot. According to our findings, high-dose NEPO improved autism-associated phenotypes. Neuroprotective effects of EPO and NEPO have been shown in the hippocampus. Postnatal NEPO treatment reversed KCC2 expression abnormalities induced by prenatal VPA. Our results might support the role of KCC2 in ASD and the excitatory/inhibitory imbalance hypothesis. We suggested Nano- erythropoietin and other KCC2 interventions as a new approach to the early treatment and prevention of autism.

Mangiferin exerts neuroprotective effects against focal cerebral ischemia in mice by regulating NF-κB signaling pathway

PURPOSE

Mangiferin is a natural free radical scavenging antioxidant that induces excitation of the central nervous system. However, the mechanism of neuroprotective effect of mangiferin on focal cerebral ischemia has not been fully investigated. The aim of this study was to investigate the protective effect of mangiferin on focal cerebral ischemia in mice.

METHODS

Middle cerebral artery occlusion (MCAO) was performed to investigate the effect of mangiferin on focal cerebral ischemia. Mice were randomly divided into 5 groups: sham, MCAO, MCAO + 5 mg/kg mangiferin, MCAO + 20 mg/kg mangiferin and MCAO + 5 mg/kg nimodipine. Neurobehavioral scores, brain edema, brain injury scores, relative infarct size and expression of some inflammatory factors in the brain were evaluated. NF-κB pathway was detected by Western blotting and immunofluorescence.

RESULTS

The results showed that mangiferin effectively attenuated MCAO-induced brain injury, including improvement of neurological impairment, reduction of brain edema, and reduction of infarct size. Compared with the MCAO group, mangiferin significantly inhibited MCAO-induced neuroinflammation, which can be proved by reduced expression levels of TNF-α, IL-1β, iNOS and COX-2. In addition, we found that phosphorylation of IκBα was inhibited and the expression of NF-κB p65 in the nucleus was reduced after the addition of mangiferin.

CONCLUSION

Our study suggested that mangiferin exerts neuroprotective effects on focal cerebral ischemia in mice by regulating the NF-κB signaling pathway. Mangiferin may be an effective treatment for cerebral ischemia and other neurological disorders.

Crosstalk Between GABAergic Neurotransmission and Inflammatory Cascades in the Post-ischemic Brain: Relevance for Stroke Recovery

Adaptive plasticity processes are required involving neurons as well as non-neuronal cells to recover lost brain functions after an ischemic stroke. Recent studies show that gamma-Aminobutyric acid (GABA) has profound effects on glial and immune cell functions in addition to its inhibitory actions on neuronal circuits in the post-ischemic brain. Here, we provide an overview of how GABAergic neurotransmission changes during the first weeks after stroke and how GABA affects functions of astroglial and microglial cells as well as peripheral immune cell populations accumulating in the ischemic territory and brain regions remote to the lesion. Moreover, we will summarize recent studies providing data on the immunomodulatory actions of GABA of relevance for stroke recovery. Interestingly, the activation of GABA receptors on immune cells exerts a downregulation of detrimental anti-inflammatory cascades. Conversely, we will discuss studies addressing how specific inflammatory cascades affect GABAergic neurotransmission on the level of GABA receptor composition, GABA synthesis, and release. In particular, the chemokines CXCR4 and CX3CR1 pathways have been demonstrated to modulate receptor composition and synthesis. Together, the actual view on the interactions between GABAergic neurotransmission and inflammatory cascades points towards a specific crosstalk in the post-ischemic brain. Similar to what has been shown in experimental models, specific therapeutic modulation of GABAergic neurotransmission and inflammatory pathways may synergistically promote neuronal plasticity to enhance stroke recovery.

The Effect of Erythropoietin and Its Derivatives on Ischemic Stroke Therapy: A Comprehensive Review

Numerous studies explored the therapeutic effects of erythropoietin (EPO) on neurodegenerative diseases. Few studies provided comprehensive and latest knowledge of EPO treatment for ischemic stroke. In the present review, we introduced the structure, expression, function of EPO, and its receptors in the central nervous system. Furthermore, we comprehensively discussed EPO treatment in pre-clinical studies, clinical trials, and its therapeutic mechanisms including suppressing inflammation. Finally, advanced studies of the therapy of EPO derivatives in ischemic stroke were also discussed. We wish to provide valuable information on EPO and EPO derivatives’ treatment for ischemic stroke for basic researchers and clinicians to accelerate the process of their clinical applications.