Spermine reduces infarction and neurological deficit following a rat model of middle cerebral artery occlusion: a magnetic resonance imaging study

Targeting Ferroptosis as a Promising Therapeutic Strategy for Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury is a major challenge in perioperative medicine that contributes to pathological damage in various conditions, including ischemic stroke, myocardial infarction, acute lung injury, liver transplantation, acute kidney injury and hemorrhagic shock. I/R damage is often irreversible, and current treatments for I/R injury are limited. Ferroptosis, a type of regulated cell death characterized by the iron-dependent accumulation of lipid hydroperoxides, has been implicated in multiple diseases, including I/R injury. Emerging evidence suggests that ferroptosis can serve as a therapeutic target to alleviate I/R injury, and pharmacological strategies targeting ferroptosis have been developed in I/R models. Here, we systematically summarize recent advances in research on ferroptosis in I/R injury and provide a comprehensive analysis of ferroptosis-regulated genes investigated in the context of I/R, as well as the therapeutic applications of ferroptosis regulators, to provide insights into developing therapeutic strategies for this devastating disease.

FPS-ZM1 Alleviates Neuroinflammation in Focal Cerebral Ischemia Rats via Blocking Ligand/RAGE/DIAPH1 Pathway

Receptor for advanced glycation end products (RAGEs), a multiligand receptor belonging to the cell-surface immunoglobulin superfamily, has been reported to play a crucial role in neuroinflammation and neurodegenerative diseases. Here, we tested our hypothesis that the RAGE-specific antagonist FPS-ZM1 is neuroprotective against ischemic brain injury. Distal middle cerebral artery occlusion (MCAO) or sham operation was performed on anesthetized Sprague-Dawley male rats (n = 60), which were then treated with FPS-ZM1 or vehicle (four groups in total = Vehicle + MCAO, FPS-ZM1 + MCAO, Vehicle + sham, and FPS-ZM1 + sham). After 1 week, neurological function was evaluated, and then, brain tissues were collected for 2,3,5-triphenyltetrazolium chloride staining, Nissl staining, TUNEL staining, Western blotting, and immunohistochemical analyses. FPS-ZM1 treatment after MCAO markedly attenuated neurological deficits and reduced the infarct area. More interestingly, FPS-ZM1 inhibited ischemia-induced astrocytic activation and microgliosis and decreased the elevated levels of proinflammatory cytokines. Furthermore, FPS-ZM1 blocked the increase in the level of RAGE and, notably, of DIAPH1, the key cytoplasmic hub for RAGE-ligand-mediated activation of cellular signaling. Accordingly, FPS-ZM1 also reversed the MCAO-induced increase in phosphorylation of NF-κB targets that are potentially downstream from RAGE/DIAPH1. Our findings reveal that FPS-ZM1 treatment reduces neuroinflammation in rats with focal cerebral ischemia and further suggest that the ligand/RAGE/DIAPH1 pathway contributes to this FPS-ZM1-mediated alleviation of neuroinflammation.

Effects of spermine and the passive avoidance learning (PAL) following cerebral ischemia in chicks: Association with neuroprotection of pyramidal cells

The aim of this study is to investigate the effects of spermine and the passive avoidance learning on hippocampus following transient cerebral ischemia in the chicks. The study is composed of the pure control (CG), sham (SG) and experimental groups (n=20). Experimental groups (ischemia group, IG and ischemia-spermine group, ISG) were exposed to ischemia for 20min whereas the SG was exposed to sham operation and CG group was not exposed to any operation. Passive avoidance learning (PAL) was applied to the half number of the subjects in each group. Both before and after 7days from the ischemia, operated animals were taken to PAL and then they were sacrificed. Total numbers of neurons in the hippocampus were stereologically estimated using Cresyl violet stained sections. We detected that number of neurons was increased following PAL and especially spermine treatment. According to our results, we suggested that spermine may reduce the deleterious effects of the ischemia by causing to increase in the neuronal number and so, it may be slightly supportive to the PAL.

Potential Therapeutic Mechanisms and Tracking of Transplanted Stem Cells: Implications for Stroke Treatment

Stem cell therapy is a promising potential therapeutic strategy to treat cerebral ischemia in preclinical and clinical trials. Currently proposed treatments for stroke employing stem cells include the replacement of lost neurons and integration into the existing host circuitry, the release of growth factors to support and promote endogenous repair processes, and the secretion of extracellular vesicles containing proteins, noncoding RNA, or DNA to regulate gene expression in recipient cells and achieve immunomodulation. Progress has been made to elucidate the precise mechanisms underlying stem cell therapy and the homing, migration, distribution, and differentiation of transplanted stem cells in vivo using various imaging modalities. Noninvasive and safe tracer agents with high sensitivity and image resolution must be combined with long-term monitoring using imaging technology to determine the optimal therapy for stroke in terms of administration route, dosage, and timing. This review discusses potential therapeutic mechanisms of stem cell transplantation for the treatment of stroke and the limitations of current therapies. Methods to label transplanted cells and existing imaging systems for stem cell labeling and in vivo tracking will also be discussed.

Restoration of Polyamine Metabolic Patterns in In Vivo and In Vitro Model of Ischemic Stroke following Human Mesenchymal Stem Cell Treatment

We investigated changes in PA levels by the treatment of human bone-marrow-derived mesenchymal stem cells (hBM-MSCs) in ischemic stroke in rat brain model and in cultured neuronal SH-SY5Y cells exposed to oxygen-glucose deprivation (OGD). In ischemic rat model, transient middle cerebral artery occlusion (MCAo) was performed for 2 h, followed by intravenous transplantation of hBM-MSCs or phosphate-buffered saline (PBS) the day following MCAo. Metabolic profiling analysis of PAs was examined in brains from three groups: control rats, PBS-treated MCAo rats (MCAo), and hBM-MSCs-treated MCAo rats (MCAo + hBM-MSCs). In ischemic cell model, SH-SY5Y cells were exposed to OGD for 24 h, treated with hBM-MSCs (OGD + hBM-MSCs) prior to continued aerobic incubation, and then samples were collected after coculture for 72 h. In the in vivo MCAo ischemic model, levels of some PAs in brain samples of the MCAo and MCAo + hBM-MSCs groups were significantly different from those of the control group. In particular, putrescine, cadaverine, and spermidine in brain tissues of the MCAo + hBM-MSCs group were significantly reduced in comparison to those in the MCAo group. In the in vitro OGD system, N¹-acetylspermidine, spermidine, N¹-acetylspermine, and spermine in cells of the OGD + hBM-MSCs group were significantly reduced compared to those of OGD group.

SP-8203 shows neuroprotective effects and improves cognitive impairment in ischemic brain injury through NMDA receptor

The extracts of earth worms, Eisenia andrei, have been used as a therapeutic agent for stroke in the traditional medicine. It is also reported that the protease fraction separated from the extracts has strong anti-thrombotic activity. Besides anti-thrombotic actions, we found that SP-8203, N-[3-(2,4-dioxo-1,4-dihydro-2H-quinazolin-3-yl)propyl]-N-{4-[3-(2,4-dioxo-1,4-dihydro-2H-quinazolin-3-yl)propylamino]butyl}acetamide, derived from the extracts of earth worms blocked N-methyl-(D)-aspartate (NMDA) receptor-mediated excitotoxicity in a competitive manner. The neuroprotective effects of SP-8203 were attributable to prevention of Ca(2+) influx through NMDA receptors. The systemic administration of SP-8203 markedly reduced neuronal death following middle cerebral artery occlusion in rats. SP-8203 significantly improved spatial learning and memory in the water maze test. These results provided strong pharmacological basis for its potential therapeutic roles in cerebral ischemia.

Properties of gap junction blockers and their behavioural, cognitive and electrophysiological effects: animal and human studies

Gap junctions play an important role in brain physiology. They synchronize neuronal activity and connect glial cells participating in the regulation of brain metabolism and homeostasis. Gap junction blockers (GJBs) include various chemicals that impair gap junction communication, disrupt oscillatory neuronal activity over a wide range of frequencies, and decrease epileptic discharges. The behavioural and clinical effects of GJBs suggest that gap junctions can be involved in the regulation of locomotor activity, arousal, memory, and breathing. Severe neuropsychiatric side effects suggest the involvement of gap junctions in mechanisms of consciousness. Unfortunately, the available GJBs are not selective and can bind to targets other than gap junctions. Other problems in behavioural studies include the possible adverse effects of GJBs, for example, retinal toxicity and hearing disturbances, changes in blood-brain transport, and the metabolism of other drugs. Therefore, it is necessary to design experiments properly to avoid false, misleading or uninterpretable results. We review the pharmacological properties and electrophysiological, behavioural and cognitive effects of the available gap junction blockers, such as carbenoxolone, glycyrrhetinic acid, quinine, quinidine, mefloquine, heptanol, octanol, anandamide, fenamates, 2-APB, several anaesthetics, retinoic acid, oleamide, spermine, aminosulfonates, and sodium propionate. It is concluded that despite a number of different problems, the currently used gap junction blockers could be useful tools in pharmacology and neuroscience.

Structural and functional recovery elicited by combined putrescine and aminoguanidine treatment after aspirative lesion of the fimbria-fornix and overlying cortex in the adult rat

Damage to the adult CNS often causes permanent deficits. Based on a lesion model of septohippocampal pathway aspiration in the rat, we attempted to promote neuronal cell survival and post-traumatic recovery by using a pharmacological treatment combining aminoguanidine and putrescine (AGP). The functional recovery was followed over 15 weeks before morphological analysis. AGP treatment produced a persistent attenuation (approximately 50%) of the lesion-induced hyperactivity, a reduction (approximately 60%) in the sensorimotor impairments and an improved performance in the water-maze task which did not, however, rely upon improved memory capabilities. AGP weakened the lesion-induced decrease in ChAT-positive neurons in the medial septum and the extent of thalamic retrograde necrosis (by approximately 30% in each case) and resulted in a partial cholinergic reinnervation of the dentate gyrus. These promising results support the idea that coadministration of putrescine and aminoguanidine might become a potent way to foster structural and functional recovery (or compensation) in the adult mammalian CNS after injury.

Polyamine and aminoguanidine treatments to promote structural and functional recovery in the adult mammalian brain after injury: a brief literature review and preliminary data about their combined administration

The regeneration potential of the adult mammalian central nervous system (CNS) is very modest, due to, among other factors, the presence of either a glial scar, or myelin-associated regeneration inhibitors such as Nogo-A, MAG and OMgp, which all interact with the same receptor (NgR). After a brief review of the key proteins (Rho and PKC) implicated in NgR-mediated signalling cascades, we will tackle the implications of cAMP and Arginase I in overcoming myelin growth-inhibitory influence, and then will focus on the effects of polyamines and aminoguanidine to propose (and to briefly support this proposal by our own preliminary data) that their association might be a potent way to enable functionally-relevant regeneration in the adult mammalian CNS.

Talampanel improves the functional deficit after transient focal cerebral ischemia in rats. A 30-day follow up study

The neuroprotective effect of talampanel, a negative allosteric modulator of alpha-amino-3-hydroxy-methyl-4-isoxazolyl-propionic acid (AMPA) receptors has been described previously. However, in these studies the histological changes and not the functional consequences of the brain damage were evaluated. The aim of present investigation was to analyze the sensorimotor function after stroke and to test the influence of talampanel (GYKI-53773, LY-300164) by 30-day monitoring in rats. After 1h middle cerebral artery occlusion (MCAO) general 'well-being', neurological status, spontaneous motor activity, rotation, motor coordination, balancing, muscle strength and reaction time were followed for 1 month. Talampanel (6 x 10 mg/kg i.p. given on the day of stroke) improved the motor coordination in rotarod (p < 0.01) and beam walking (p < 0.01) tests, reduced the number of stroke-induced rotations (p < 0.05), shortened the reflex time on the forelimb contralateral to brain ischemia and improved the survival rate comparing with vehicle treated control. After stroke, serious sensorimotor deficits appeared in rats but they showed partial spontaneous recovery after 30 days. Talampanel treatment enhanced the rate of functional improvement without changing the morphology at the end of the experiment. Our results indicate that modulation of AMPA receptors by talampanel can be a promising therapeutic approach to the treatment of stroke.