Curcumin: Novel Treatment in Neonatal Hypoxic-Ischemic Brain Injury

Hypoxic-Ischemic Encephalopathy: Pathogenesis and Promising Therapies

Hypoxic-ischemic encephalopathy (HIE) is a brain lesion caused by inadequate blood supply and oxygen deprivation, often occurring in neonates. It has emerged as a grave complication of neonatal asphyxia, leading to chronic neurological damage. Nevertheless, the precise pathophysiological mechanisms underlying HIE are not entirely understood. This paper aims to comprehensively elucidate the contributions of hypoxia-ischemia, reperfusion injury, inflammation, oxidative stress, mitochondrial dysfunction, excitotoxicity, ferroptosis, endoplasmic reticulum stress, and apoptosis to the onset and progression of HIE. Currently, hypothermia therapy stands as the sole standard treatment for neonatal HIE, albeit providing only partial neuroprotection. Drug therapy and stem cell therapy have been explored in the treatment of HIE, exhibiting certain neuroprotective effects. Employing drug therapy or stem cell therapy as adjunctive treatments to hypothermia therapy holds great significance. This article presents a systematic review of the pathogenesis and treatment strategies of HIE, with the goal of enhancing the effect of treatment and improving the quality of life for HIE patients.

Protopine Exerts Neuroprotective Effects on Neonatal Hypoxic-Ischemic Brain Damage in Rats via Activation of the AMPK/PGC1α Pathway

Introduction

Neonatal hypoxic-ischemic encephalopathy (HIE), caused by perinatal asphyxia, is characterized by high morbidity and mortality, but there are still no effective therapeutic drugs. Mitochondrial biogenesis and apoptosis play key roles in the pathogenesis of HIE. Protopine (Pro), an isoquinoline alkaloid, has anti-apoptotic and neuro-protective effects. However, the protective roles of Pro on neonatal hypoxic-ischemic brain injury remain unclear.

Methods

In this study, we established a CoCl2-induced PC12 cell model in vitro and a neonatal rat hypoxic-ischemic (HI) brain damage model in vivo to explore the neuro-protective effects of Pro and try to elucidate the potential mechanisms.

Results

Our results showed that Pro significantly reduced cerebral infarct volume, alleviated brain edema, inhibited glia activation, improved mitochondrial biogenesis, relieved neuron cell loss, decreased cell apoptosis and reactive oxygen species (ROS) after HI damage. In addition, Pro intervention upregulated the levels of p-AMPK/AMPK and PGC1α as well as the downstream mitochondrial biogenesis related factors, such as nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), but the AMPK inhibitor compound c (CC) could significantly reverse these effects of Pro.

Discussion

Pro may exert neuroprotective effects on neonatal hypoxic-ischemic brain damage via activation of the AMPK/PGC1α pathway, suggesting that Pro may be a promising therapeutic candidate for HIE, and our study firstly demonstrate the neuro-protective roles of Pro in HIE models.

CYR61 is Involved in Neonatal Hypoxic-ischemic Brain Damage Via Modulating Astrocyte-mediated Neuroinflammation

The activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome in astrocytes has been found in the hypoxic-ischemic brain damage (HIBD) model. Cysteine rich angiogenic inducer 61 (CYR61) is secreted by reactive astrocytes. However, the effects of CYR61 on HIBD and its related mechanisms remain unclear. This study sought to explore the role of CYR61 in the activation of astrocytes and the NLRP3 inflammasome in neonatal HIBD. HIBD models were established in 7-day Sprague-Dawley rat pups. Neurobehavioral evaluation and 2,3,5-triphenyl-tetrazolium chloride staining were performed. In addition, rat primary astrocytes were used to establish the cell model of HIBD in vitro by oxygen-glucose deprivation/reperfusion (OGD/R). Then, CYR61-overexpression and sh-CYR61 viruses mediated by lentivirus were transduced into ODG/R-treated primary astrocytes. The expressions of related genes were evaluated using real-time quantitative PCR, western blot, immunofluorescence staining, and Enzyme-linked immunosorbent assay. The results showed that hypoxia-ischemia induced short-term neurological deficits, neuronal damage, and cerebral infarction in neonatal rats. In vivo, the expressions of CYR61, NLRP3, and glial fibrillary acidic protein (GFAP) were up-regulated in the HIBD model. In vitro, CYR61 exhibited high expression. CYR61 overexpression increased the expressions of GFAP and C3, whereas decreased S100A10 expression. CYR61 overexpression increased the expression of NLRP3, ASC, caspase-1 p20 and IL-1β. CYR61 overexpression activated NF-κB by promoting the phosphorylation of IκBα and p65. Thus, CYR61 is involved in neonatal HIBD progress, which may be related to the activation of astrocytes, the NLRP3 inflammasome, and the NF-κB signaling pathway.

Aloesin ameliorates hypoxic-ischemic brain damage in neonatal mice by suppressing TLR4-mediated neuroinflammation

BACKGROUND

At present, neonatal hypoxic-ischemic encephalopathy (HIE), especially moderate to severe HIE, is a challenging disease for neonatologists to treat, and new alternative/complementary treatments are urgently needed. The neuroinflammatory cascade triggered by hypoxia-ischemia (HI) insult is one of the core pathological mechanisms of HIE. Early inhibition of neuroinflammation provides long-term neuroprotection. Plant-derived monomers have impressive anti-inflammatory effects. Aloesin (ALO) has been shown to have significant anti-inflammatory and antioxidant effects in diseases such as ulcerative colitis, but its role in HIE is unclear. To this end, we conducted a series of experiments to explore the potential mechanism of ALO in preventing and treating brain damage caused by HI insult.

MATERIALS AND METHODS

Hypoxic-ischemic brain damage (HIBD) was induced in 7-day-old Institute of Cancer Research (ICR) mice, which were then treated with 20 mg/kg ALO. The neuroprotective effects of ALO on HIBD and the underlying mechanism were evaluated through neurobehavioral testing, infarct size measurement, apoptosis detection, protein and messenger RNA level determination, immunofluorescence, and molecular docking.

RESULTS

ALO alleviated the long-term neurobehavioral deficits caused by HI insult; reduced the extent of cerebral infarction; inhibited cell apoptosis; decreased the levels of the inflammatory factors interleukin (IL)-1β, IL-6, and tumor necrosis factor-α; activated microglia and astrocytes; and downregulated the protein expression of members in the TLR4 signaling pathway. In addition, molecular docking showed that ALO can bind stably to TLR4.

CONCLUSION

ALO ameliorated HIBD in neonatal mice by inhibiting the neuroinflammatory response mediated by TLR4 signaling.

Diallyl disulfide attenuates pyroptosis via NLRP3/Caspase-1/IL-1β signaling pathway to exert a protective effect on hypoxic-ischemic brain damage in neonatal rats

Hypoxic-ischemic encephalopathy (HIE) is a perinatal brain disease caused by hypoxia in neonates. It is one of the leading causes of neonatal death in the perinatal period, as well as disability beyond the neonatal period. Due to the lack of a unified and comprehensive treatment strategy for HIE, research into its pathogenesis is essential. Diallyl disulfide (DADS) is an allicin extract, with detoxifying, antibacterial, and cardiovascular disease protective effects. This study aimed to determine whether DADS can alleviate HIE induced brain damage in rats and oxygen-glucose deprivation (OGD)-induced pyroptosis in PC12 cells, as well as whether it can inhibit pyroptosis via the NLRP3/Caspase-1/IL-1β signaling pathway. In vivo, DADS significantly reduced the cerebral infarction volume, alleviated inflammatory reaction, reduced astrocyte activation, promoted tissue structure recovery, improved pyroptosis caused by HIE and improved the prognosis following HI injury. In vitro findings indicated that DADS increased cell activity, decreased LDH activity and reduced the expression of pyroptosis-related proteins, including IL-1β, IL-18, and certain inflammatory factors in PC12 cells caused by OGD. Mechanistically, DADS inhibited pyroptosis and protected against HIE via the NLRP3/Caspase-1/IL-1β pathway. The specific inhibitor of caspase-1, VX-765, inhibited caspase-1 activation, and IL-1β expression was determined. Additionally, the overexpression of NLRP3 reversed the protective effect of allicin against OGD-induced pyroptosis. In conclusion, these findings demonstrated that DADS inhibits the NLRP3/Caspase-1/IL-1β signaling pathway and decreases HI brain damage.

Role of curcumin in ischemia and reperfusion injury

Ischemia-reperfusion injury (IRI) is an inevitable pathological process after organic transplantations. Although traditional treatments restore the blood supply of ischemic organs, the damage caused by IRI is always ignored. Therefore, the ideal and effective therapeutic strategy to mitigate IRI is warrented. Curcumin is a type of polyphenols, processing such properties as anti-oxidative stress, anti-inflammation and anti-apoptosis. However, although many researches have been confirmed that curcumin can exert great effects on the mitigation of IRI, there are still some controversies about its underlying mechanisms among these researches. Thus, this review is to summarize the protective role of curcumin against IRI as well as the controversies of current researches, so as to clarify its underlying mechanisms clearly and provide clinicians a novel idea of the therapy for IRI.

Antioxidants: an approach for restricting oxidative stress induced neurodegeneration in Alzheimer's disease

Alzheimer's disease (AD) is the leading cause of dementia, affecting millions of people worldwide. Oxidative stress contributes towards induction of neurodegeneration. It is one of the reasons behind initiation and progression of Alzheimer's disease. Understanding of oxidative balance and restoration of oxidative stress has demonstrated its effectiveness in the management of AD. Various natural and synthetic molecules have been found to be effective in different models of AD. Some clinical studies also support the use of antioxidants for prevention of neurodegeneration in AD. In this review we are summarizing the development of antioxidants to restrict oxidative stress induced neurodegeneration in AD.

Plant based food bioactives: A boon or bane for neurological disorders

Neurological disorders are the foremost occurring diseases across the globe resulting in progressive dysfunction, loss of neuronal structure ultimately cell death. Therefore, attention has been drawn toward the natural resources for the search of neuroprotective agents. Plant-based food bioactives have emerged as potential neuroprotective agents for the treatment of neurodegenerative disorders. This comprehensive review primarily focuses on various plant food bioactive, mechanisms, therapeutic targets, in vitro and in vivo studies in the treatment of neurological disorders to explore whether they are boon or bane for neurological disorders. In addition, the clinical perspective of plant food bioactives in neurological disorders are also highlighted. Scientific evidences point toward the enormous therapeutic efficacy of plant food bioactives in the prevention or treatment of neurological disorders. Nevertheless, identification of food bioactive components accountable for the neuroprotective effects, mechanism, clinical trials, and consolidation of information flow are warranted. Plant food bioactives primarily act by mediating through various pathways including oxidative stress, neuroinflammation, apoptosis, excitotoxicity, specific proteins, mitochondrial dysfunction, and reversing neurodegeneration and can be used for the prevention and therapy of neurodegenerative disorders. In conclusion, the plant based food bioactives are boon for neurological disorders.

Bioactives and functional food ingredients with promising potential for the management of cerebral and myocardial ischemia: a comprehensive mechanistic review

Ischemia is a deadly disease featured by restricted perfusion to different organs in the body. An increase in the accumulation of reactive oxygen species and cell debris is the driving force for inducing many oxidative, inflammatory and apoptotic signaling pathways. However, the number of therapeutics existing for ischemic stroke patients is limited and there is insufficient data on their efficiency, which warrants the search for novel therapeutic candidates from natural sources. Herein, a comprehensive survey was done on the reported functional food bioactives (ca. 152 compounds) to manage or protect against health consequences of myocardial and cerebral ischemia. Furthermore, we reviewed the reported mechanistic studies for their anti-ischemic potential. Subsequently, network pharmacology- and in silico-based studies were conducted using the reported myocardial and cerebral ischemia-relevant molecular targets to study their complex interactions and highlight key targets in disease pathogenesis. Subsequently, the most prominent 20 compounds in the literature were used in a comprehensive in silico-based analysis (inverse docking, ΔG calculation and molecular dynamics simulation) to determine other potential targets for these compounds and their probable interactions with different signaling pathways relevant to this disease. Many functional food bioactives, belonging to different chemical classes, i.e., flavonoids, saponins, phenolics, alkaloids, iridoids and carotenoids, were proven to exhibit multifactorial effects in targeting the complex pathophysiology of ischemic conditions. These merits make them valuable therapeutic agents that can outperform the conventional drugs, and hence they can be utilized as add-ons to the conventional therapy for the management of different ischemic conditions; however, their rigorous clinical assessment is necessary.

Chlorogenic acid exerts neuroprotective effect against hypoxia-ischemia brain injury in neonatal rats by activating Sirt1 to regulate the Nrf2-NF-κB signaling pathway

Background

Neonatal hypoxic-ischemic brain injury (HIE) is caused by perinatal asphyxia, which is associated with various confounding factors. Although studies on the pathogenesis and treatment of HIE have matured, sub-hypothermia is the only clinical treatment available for HIE. Previous evidence indicates that chlorogenic acid (CGA) exerts a potential neuroprotective effect on brain injury. However, the role of CGA on neonatal HI brain damage and the exact mechanism remains elusive.

Here, we investigate the effects of CGA on HI models in vivo and in vitro and explore the underlying mechanism.

Methods

In the in vivo experiment, we ligated the left common carotid artery of 7-day-old rats and placed the rats in a hypoxic box for 2 h. We did not ligate the common carotid artery of the pups in the sham group since they did not have hypoxia. Brain atrophy and infarct size were evaluated by Nissl staining, HE staining and 2,3,5-triphenyltetrazolium chloride monohydrate (TTC) staining. Morris Water Maze test (MWM) was used to evaluate neurobehavioral disorders. Western-blotting and immunofluorescence were used to detect the cell signaling pathway. Malondialdehyde (MDA) content test, catalase (CAT) activity detection and Elisa Assay was used to detect levels of inflammation and oxidative stress. in vitro experiments were performed on isolated primary neurons.

Result

In our study, pretreatment with CGA significantly decreased the infarct volume of neonatal rats after HI, alleviated brain edema, and improved tissue structure in vivo. Moreover, we used the Morris water maze to verify CGA’s effects on enhancing the learning and cognitive ability and helping to maintain the long-term spatial memory after HI injury. However, Sirt1 inhibitor EX-527 partially reversed these therapeutic effects. CGA pretreatment inhibited neuronal apoptosis induced by HI by reducing inflammation and oxidative stress. The findings suggest that CGA potentially activates Sirt1 to regulate the Nrf2-NF-κB signaling pathway by forming complexes thereby protecting primary neurons from oxygen-glucose deprivation (OGD) damage. Also, CGA treatment significantly suppresses HI-induced proliferation of glial.

Conclusion

Collectively, this study uncovered the underlying mechanism of CGA on neonatal HI brain damage. CGA holds promise as an effective neuroprotective agent to promote neonatal brain recovery from HI-induced injury.

Graphical Abstract

Pharmacological Neuroprotection of the Preterm Brain: Current Evidence and Perspectives

Despite improvements in viability, the long-term neurodevelopmental outcomes of preterm babies remain serious concern as a significant percentage of these infants develop neurological and/or intellectual impairment, and they are also at increased risk of psychiatric illnesses later in life. The current challenge is to develop neuroprotective approaches to improve adverse outcomes in preterm survivors. The purpose of this review was to provide an overview of the current evidence on pharmacological agents targeting the neuroprotection of the preterm brain. Among them, magnesium sulfate, given antenatally to pregnant women with imminent preterm birth before 30 to 34 weeks of gestation, as well as caffeine administered to preterm infants after birth, exhibited neuroprotective effects for human preterm brain. Erythropoietin treatment of preterm infants did not result in neuroprotection at 2 years of age in two out of three published large randomized controlled trials; however, long-term follow-up of these infants is needed to come to definite conclusions. Further studies are also required to assess whether melatonin, neurosteroids, inhaled nitric oxide, allopurinol, or dietary supplements (omega-3 fatty acids, choline, curcumin, etc.) could be implemented as neuroprotectants in clinical practice. Furthermore, other pharmacological agents showing promising signs of neuroprotective efficacy in preclinical studies (growth factors, hyaluronidase inhibitors or treatment, antidiabetic drugs, cannabidiol, histamine-H3 receptor antagonists, etc.), as well as stem cell- or exosomal-based therapies and nanomedicine, may prove useful in the future as potential neuroprotective approaches for human preterm brain. KEY POINTS: · Magnesium and caffeine have neuroprotective effects for the preterm brain.. · Follow-up of infants treated with erythropoietin is needed.. · Neuroprotective efficacy of several drugs in animals needs to be shown in humans..

Restoring the oxidative balance in age-related diseases - An approach in glaucoma

As human life expectancy increases, age-related health issues including neurodegenerative diseases continue to rise. Regardless of genetic or environmental factors, many neurodegenerative conditions share common pathological mechanisms, such as oxidative stress, a hallmark of many age-related health burdens. In this review, we describe oxidative damage and mitochondrial dysfunction in glaucoma, an age-related neurodegenerative eye disease affecting 80 million people worldwide. We consider therapeutic approaches used to counteract oxidative stress in glaucoma, including untapped treatment options such as novel plant-derived antioxidant compounds that can reduce oxidative stress and prevent neuronal loss. We summarize the current pre-clinical models and clinical work exploring the therapeutic potential of a range of candidate plant-derived antioxidant compounds. Finally, we explore advances in drug delivery systems, particular those employing nanotechnology-based carriers which hold significant promise as a carrier for antioxidants to treat age-related disease, thus reviewing the key current state of all of the aspects required towards translation.

Human amniotic fluid derived-exosomes alleviate hypoxic encephalopathy by enhancing angiogenesis in neonatal mice after hypoxia

Neonatal hypoxic encephalopathy is a type of central nervous system dysfunction manifested by high mortality and morbidity. Exosomes play a crucial role in neuroprotection by enhancing angiogenesis. The objective of this study was to investigate the effect of human amniotic fluid-derived exosomes (hAFEXOs) on functional recovery in neonatal hypoxic encephalopathy. The transwell assay, scratch wound healing assay, and tube formation assay were used to evaluate the effect of hAFEXOs on the angiogenesis of human umbilical vein endothelial cells (HUVECs) after oxygen and glucose deprivation (OGD). The angiogenesis of microvascular endothelial cells (MECs) in the cortex was tested in neonatal mice treated with hAFEXOs or phosphate-buffered saline (PBS) after hypoxia. Expressions of hypoxia-inducible factor 1 α (HIF-1α) and vascular endothelial growth factor (VEGF) in the cerebral cortex were also tested by western blot. The Morris Water Maze Test (MWM) was carried out to detect the performance of spatial memory after processing with hAFEXOs or PBS. The results indicated that hAFEXOs favored tubing formation and migration of HUVECs after in vitro OGD. The hAFEXOs also favored the expression of CD31 in neonatal mice following hypoxia. The expressions of both HIF-1α and VEGF were significantly augmented in the cerebral cortex of neonatal mice which were treated with hAFEXOs. Moreover, the MWM test results showed that the performance of the spatial memory was better in the hAFEXO-treated group than in the PBS-treated group. Our study indicates that hAFEXOs alleviated hypoxic encephalopathy and enhanced angiogenesis in neonatal mice after hypoxia. In addition, hAFEXOs  promoted migration and tube formation of HUVECs after OGD in vitro. These findings confirm that hAFEXOs show great potential for further studies aimed at developing therapeutic agents for hypoxic encephalopathy.

Antioxidant for Neurological Diseases and Neurotrauma and Bioengineering Approaches

Antioxidants are a class of molecules with an innate affinity to neutralize reactive oxygen species (ROS), which are known to cause oxidative stress. Oxidative stress has been associated with a wide range of diseases mediated by physiological damage to the cells. ROS play both beneficial and detrimental roles in human physiology depending on their overall concentration. ROS are an inevitable byproduct of the normal functioning of cells, which are produced as a result of the mitochondrial respiration process. Since the establishment of the detrimental effect of oxidative stress in neurological disorders and neurotrauma, there has been growing interest in exploring antioxidants to rescue remaining or surviving cells and reverse the neurological damage. In this review, we present the survey of different antioxidants studied in neurological applications including neurotrauma. We also delve into bioengineering approaches developed to deliver antioxidants to improve their cellular uptake in neurological applications.

Curcumin Ameliorates White Matter Injury after Ischemic Stroke by Inhibiting Microglia/Macrophage Pyroptosis through NF-κB Suppression and NLRP3 Inflammasome Inhibition

NLRP3 inflammasome-mediated pyroptosis is a proinflammatory programmed cell death pathway, which plays a vital role in functional outcomes after stroke. We previously described the beneficial effects of curcumin against stroke-induced neuronal damage through modulating microglial polarization. However, the impact of curcumin on microglial pyroptosis remains unknown. Here, stroke was modeled in mice by middle cerebral artery occlusion (MCAO) for 60 minutes and treated with curcumin (150 mg/kg) intraperitoneally immediately after reperfusion, followed by daily administrations for 7 days. Curcumin ameliorated white matter (WM) lesions and brain tissue loss 21 days poststroke and improved sensorimotor function 3, 10, and 21 days after stroke. Furthermore, curcumin significantly reduced the number of gasdermin D⁺ (GSDMD⁺) Iba1⁺ and caspase-1⁺Iba1⁺ microglia/macrophage 21 days after stroke. In vitro, lipopolysaccharide (LPS) with ATP treatment was used to induce pyroptosis in primary microglia. Western blot revealed a decrease in pyroptosis-related proteins, e.g., GSDMD-N, cleaved caspase-1, NLRP3, IL-1β, and IL-18, following in vitro or in vivo curcumin treatment. Mechanistically, both in vivo and in vitro studies confirmed that curcumin inhibited the activation of the NF-κB pathway. NLRP3 knocked down by siRNA transfection markedly increased the inhibitory effects of curcumin on microglial pyroptosis and proinflammatory responses, both in vitro and in vivo. Furthermore, stereotaxic microinjection of AAV-based NLRP3 shRNA significantly improved sensorimotor function and reduced WM lesion following curcumin treatment in MCAO mice. Our study suggested that curcumin reduced stroke-induced WM damage, improved functional outcomes, and attenuated microglial pyroptosis, at least partially, through suppression of the NF-κB/NLRP3 signaling pathway, further supporting curcumin as a potential therapeutic drug for stroke.

Current Therapies for Neonatal Hypoxic-Ischaemic and Infection-Sensitised Hypoxic-Ischaemic Brain Damage

Neonatal hypoxic-ischaemic brain damage is a leading cause of child mortality and morbidity, including cerebral palsy, epilepsy, and cognitive disabilities. The majority of neonatal hypoxic-ischaemic cases arise as a result of impaired cerebral perfusion to the foetus attributed to uterine, placental, or umbilical cord compromise prior to or during delivery. Bacterial infection is a factor contributing to the damage and is recorded in more than half of preterm births. Exposure to infection exacerbates neuronal hypoxic-ischaemic damage thus leading to a phenomenon called infection-sensitised hypoxic-ischaemic brain injury. Models of neonatal hypoxia-ischaemia (HI) have been developed in different animals. Both human and animal studies show that the developmental stage and the severity of the HI insult affect the selective regional vulnerability of the brain to damage, as well as the subsequent clinical manifestations. Therapeutic hypothermia (TH) is the only clinically approved treatment for neonatal HI. However, the number of HI infants needed to treat with TH for one to be saved from death or disability at age of 18-22 months, is approximately 6-7, which highlights the need for additional or alternative treatments to replace TH or increase its efficiency. In this review we discuss the mechanisms of HI injury to the immature brain and the new experimental treatments studied for neonatal HI and infection-sensitised neonatal HI.

Olig2 knockdown alleviates hypoxic-ischemic brain damage in newborn rats

OBJECTIVES

Neuronal damage is an important pathological mechanism in neonatal hypoxic-ischemic brain damage (HIBD). We found in our previous studies that oligodendrocyte transcription factor 2 (Olig2) downregulation was able to increase cell survival in the brain. However, the specific mechanism has yet to be clarified.

METHODS

Sprague-Dawley rats aged 3 d were randomly divided into three groups: the normal control group, the Olig2-RNAi group, and the RNAi-negative control group. The normal control group received no treatment, the Olig2-RNAi group received the Olig2 RNAi adenovirus, and the RNAi-negative control group was given the control adenovirus after the completion of the HIBD model. Infarct lesions and their volumes were observed by triphenyltetrazolium chloride (TTC) staining 3 d after the completion of the adenovirus local injection. The condition of the tissue was characterized by hematoxylin-eosin staining 7 d after the model was established, and cell viability was determined by azure methylene blue staining. Subcellular damage was analyzed by transmission electron microscopy. Rotarod analysis was performed to detect moving behavior ability and an MWM assay was conducted to evaluate the memory.

RESULTS

TTC staining showed a smaller brain injury area in the Olig2-RNAi group than in the RNAi-negative control group. Hematoxylin-eosin staining indicated the presence of severe cell injury in the hippocampal region after HIBD, which improved after Olig2 knockdown. Azure methylene blue staining and electron microscopy results suggested that the cells improved after Olig2 knockdown. The rats stayed longer on the rotating rod, and their latency in the water maze test was gradually shortened relative to that of the rats in the Olig2-RNAi negative control group.

CONCLUSION

Olig2 knockdown can promote the repair of hypoxic-ischemic brain damage in newborn rats.

Exosomes derived from human amniotic fluid mesenchymal stem cells alleviate cardiac fibrosis via enhancing angiogenesis in vivo and in vitro

Background

Cardiac fibrosis is a pathological process characterized by excess extracellular matrix (ECM) deposition and plays a critical role in nearly all types of heart disease. The mechanism of cardiac fibrosis is still unclear and no effective medication treatment of cardiac fibrosis. Research showed that mesenchymal stem cell (MSC) derived exosomes may play a critical role in cardiac fibrosis. The effect of human amniotic fluid MSC (hAFMSC)-derived exosomes (hAFMSCExos) on cardiac fibrosis has remained unclear.

Methods

The hAFMSCExos were extracted using a sequential centrifugation approach. The effects of hAFMSCExos on angiogenesis were analyzed both in human umbilical vein endothelial cells (HUVECs) after oxygen and glucose deprivation (OGD) in vitro, and in isoproterenol (ISO) induced-cardiac fibrosis in vivo.

Results

The hAFMSCExos remarkably up-regulate the motility and migration of HUVECs after OGD compared with phosphate-buffered saline (PBS). Meanwhile, total tube length, total branching points and total loops were significantly raised in HUVECs after OGD treated with hAFMSCExos. The hAFMSCExos alleviated the cardiac fibrosis degree tested by hematoxylin-eosin (H&E) and Masson staining. The protein levels of Collagen I and α-smooth muscle actin (α-SMA) were lower in exosomes group rats than PBS group. Immunofluorescence suggested that hAFMSCExos can promote the expression of CD31 in the rats. Meanwhile, the number of regenerated microvessels was significantly enhanced in rats administrated with exosomes by quantitative analysis of microvessel density. Furthermore, the micro-CT scanning evidenced that hAFMSCExos promote angiogenesis after cardiac fibrosis. The levels of hypoxia-inducible factor 1 α (HIF-1α) and vascular endothelial growth factor (VEGF) expression in the left ventricle accepted HUVECs were higher than PBS treatment at 7 days post-treatment by Western blot analysis.

Conclusions

The hAFMSCExos have proangiogenic effects on endothelial cells and enhanced angiogenesis in cardiac fibrosis. The hAFMSCExos may be a promising potential treatment strategy for cardiac fibrosis.

Drug delivery platforms for neonatal brain injury

Hypoxic-ischemic encephalopathy (HIE), initiated by the interruption of oxygenated blood supply to the brain, is a leading cause of death and lifelong disability in newborns. The pathogenesis of HIE involves a complex interplay of excitotoxicity, inflammation, and oxidative stress that results in acute to long term brain damage and functional impairments. Therapeutic hypothermia is the only approved treatment for HIE but has limited effectiveness for moderate to severe brain damage; thus, pharmacological intervention is explored as an adjunct therapy to hypothermia to further promote recovery. However, the limited bioavailability and the side-effects of systemic administration are factors that hinder the use of the candidate pharmacological agents. To overcome these barriers, therapeutic molecules may be packaged into nanoscale constructs to enable their delivery. Yet, the application of nanotechnology in infants is not well examined, and the neonatal brain presents unique challenges. Novel drug delivery platforms have the potential to magnify therapeutic effects in the damaged brain, mitigate side-effects associated with high systemic doses, and evade mechanisms that remove the drugs from circulation. Encouraging pre-clinical data demonstrates an attenuation of brain damage and increased structural and functional recovery. This review surveys the current progress in drug delivery for treating neonatal brain injury.

Curcumin Loaded Polymeric vs. Lipid Nanoparticles: Antioxidant Effect on Normal and Hypoxic Olfactory Ensheathing Cells

Background: Curcumin (Cur) shows anti-inflammatory and antioxidant effects on central nervous system diseases. The aim of this study was to develop Cur-loaded polymeric and lipid nanoparticles for intranasal delivery to enhance its stability and increase antioxidant effect on olfactory ensheathing cells (OECs). Methods: The nanosuspensions were subjected to physico-chemical and technological evaluation through photon correlation spectroscopy (PCS), differential scanning calorimetry (DSC) and UV-spectrophotometry. The cytotoxicity studies of nanosuspensions were carried out on OECs. A viability test was performed after 24 h of exposure of OECs to unloaded and curcumin-loaded nanosuspensions. The potential protective effect of Cur was assessed on hypoxic OECs cells. Uptake studies were performed on the same cell cultures. Thermal analysis was performed to evaluate potential interaction of Cur with a 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) biomembrane model. Results: PCS analysis indicated that lipid and polymeric nanosuspensions showed a mean size of 127.10 and 338.20 nm, respectively, high homogeneity and negative zeta potential. Incorporation of Cur into both nanocarriers increased drug stability up to 135 days in cryoprotected freeze-dried nanosuspensions. Cell viability was improved when hypoxic OECs were treated with Cur-loaded polymeric and lipid nanosuspensions compared with the control. Conclusions: Both nanocarriers could improve the stability of Cur as demonstrated by technological studies. Biological studies revealed that both nanocarriers could be used to deliver Cur by intranasal administration for brain targeting.

From Preclinical Stroke Models to Humans: Polyphenols in the Prevention and Treatment of Stroke

Polyphenols are an important family of molecules of vegetal origin present in many medicinal and edible plants, which represent important alimentary sources in the human diet. Polyphenols are known for their beneficial health effects and have been investigated for their potential protective role against various pathologies, including cancer, brain dysfunctions, cardiovascular diseases and stroke. The prevention of stroke promoted by polyphenols relies mainly on their effect on cardio- and cerebrovascular systems. However, a growing body of evidence from preclinical models of stroke points out a neuroprotective role of these molecules. Notably, in many preclinical studies, the polyphenolic compounds were effective also when administered after the stroke onset, suggesting their possible use in promoting recovery of patients suffering from stroke. Here, we review the effects of the major polyphenols in cellular and in vivo models of both ischemic and hemorrhagic stroke in immature and adult brains. The results from human studies are also reported.

SARS-CoV-2 and mitochondrial health: implications of lifestyle and ageing

Infection with SARs-COV-2 displays increasing fatality with age and underlying co-morbidity, in particular, with markers of the metabolic syndrome and diabetes, which seems to be associated with a "cytokine storm" and an altered immune response. This suggests that a key contributory factor could be immunosenescence that is both age-related and lifestyle-induced. As the immune system itself is heavily reliant on mitochondrial function, then maintaining a healthy mitochondrial system may play a key role in resisting the virus, both directly, and indirectly by ensuring a good vaccine response. Furthermore, as viruses in general, and quite possibly this new virus, have also evolved to modulate immunometabolism and thus mitochondrial function to ensure their replication, this could further stress cellular bioenergetics. Unlike most sedentary modern humans, one of the natural hosts for the virus, the bat, has to "exercise" regularly to find food, which continually provides a powerful adaptive stimulus to maintain functional muscle and mitochondria. In effect the bat is exposed to regular hormetic stimuli, which could provide clues on how to resist this virus. In this paper we review the data that might support the idea that mitochondrial health, induced by a healthy lifestyle, could be a key factor in resisting the virus, and for those people who are perhaps not in optimal health, treatments that could support mitochondrial function might be pivotal to their long-term recovery.

Morroniside protects HT-22 cells against oxygen-glucose deprivation/reperfusion through activating the Nrf2/HO-1 signaling pathway

Neonatal hypoxic-ischemic encephalopathy (HIE) is a devastating condition that affects neurodevelopment and results in brain injury in infants. Morroniside (MOR), a natural secoiridoid glycoside, has been found to possess neuroprotective effect. However, the effects of MOR on neonatal HIE are unclear. An in vitro HIE model was established in murine hippocampal neurons HT-22 cells using oxygen-glucose deprivation/reoxygenation (OGD/R) stimulation. Our results showed that MOR improved OGD/R-caused cell viability reduction in HT-22 cells. MOR suppressed the production of reactive oxygen species (ROS) and malondialdehyde (MDA) in OGD/R-induced HT-22 cells in a dose-dependent manner. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GP_X) were significantly elevated by MOR. Moreover, MOR treatment caused a significant increase in bcl-2 expression, and obvious decreases in the expression levels of bax, cleaved caspase-3, and cleaved caspase-9 expression. Furthermore, MOR significantly upregulated the expression levels of nuclear Nrf2 and HO-1 in OGD/R-treated HT-22 cells. Additionally, knockdown of Nrf2 or HO-1 abrogated the effects of MOR on OGD/R-induced oxidative stress and apoptosis in HT-22 cells. In conclusion, these findings suggested that MOR protects HT-22 cells against OGD/R via regulating the Nrf2/HO-1 signaling pathway.

Study of the modulatory mechanism of the miR-182-Clock axis in circadian rhythm disturbance after hypoxic–ischemic brain damage

Hypoxic–ischemic encephalopathy (HIE) in neonates can lead to severe chronic neurological deficit, including mental retardation, epilepsy, and sleep–wake cycle (SWC) disorder. Among these defects, little is known about the molecular mechanism of circadian rhythm disorder after HIE. Therefore, further study of sleep problems and its mechanism in HIE children will provide new ideas for clinical treatment of HIE children. For pediatric patients with cerebral ischemia, somnipathy often occurs due to visual and airway abnormalities. From May 2010 to August 2013, 128 newborns with history of HIE were followed up. Meanwhile, 88 normal full-term newborns in the same period were taken as the control group. The clinical data of the patients were collected and the sleep status was assessed by questionnaire. To establish the hypoxic–ischemic brain injury model of neonatal rats and analyze the mechanism of mir-182 in the circadian rhythm disorder caused by pineal function injury. The core clock genes during the regulation of the circadian clock were explored by bioinformatics methods. Patients’ sleep quality was affected by the circadian rhythm and respiratory problems; the pineal gland can regulate the core clock genes in the circadian clock during regulation. miR-182 was highly expressed in the pineal gland after hypoxic–ischemic brain damage (HIBD). Children with mild and moderate HIE showed significant sleep disorders in varying degrees, which provided a clinical basis for improving the long-term prognosis of children with HIE through targeted treatment of sleep disorders. MiR-182 is highly expressed in the pineal gland and is related to the expression of CLOCK protein. CLOCK gene is the target gene of miR-182, which provides a new target for the treatment of rhythm disorder related to the damage of pineal function caused by HIBD.