Curcumin prevents reperfusion injury following ischemic stroke in rats via inhibition of NF‑κB, ICAM-1, MMP-9 and caspase-3 expression

The beneficial effects of curcumin on aging and age-related diseases: from oxidative stress to antioxidant mechanisms, brain health and apoptosis

Aging and age-related disease are among the most common and challenging issues worldwide. During the aging process, the accumulation of oxidative stress, DNA damage, telomere dysfunction, and other related changes lead to cellular dysfunction and the development of diseases such as neurodegenerative and cardiovascular conditions. Curcumin is a widely-used dietary supplement against various diseases such as cancer, diabetes, cardiovascular diseases and aging. This agent mediates its effects through several mechanisms, including the reduction of reactive oxygen species (ROS) and oxidative stress-induced damage, as well as the modulation of subcellular signaling pathways such as AMPK, AKT/mTOR, and NF-κB. These pathways are involved in cellular senescence and inflammation, and their modulation can improve cell function and help prevent disease. In cancer, Curcumin can induce apoptosis in a variety of different tumor cell lines. Curcumin also activates redox reactions within cells inducing ROS production that leads to the upregulation of apoptosis receptors on the tumor cell membrane. Curcumin can also upregulate the expression and activity of p53 that inhibits tumor cell proliferation and increases apoptosis. Furthermore, curcumin has a potent inhibitory effect on the activity of nuclear factor kappa B (NF-κB) and cyclooxygenase-2 (COX-2), which are involved in the overexpression of antiapoptosis genes such as Bcl-2. It can also attenuate the regulation of antiapoptosis phosphoinositide 3-kinases (PI3K) signaling and increase the expression of mitogen-activated protein kinases (MAPKs) to induce endogenous production of ROS. Therefore, herein, we aim to summarize how curcumin affect different epigenetic processes (such as apoptosis and oxidative stress) in order to change aging-related mechanisms. Furthermore, we discuss its roles in age-related diseases, such as Alzheimer, Parkinson, osteoporosis, and cardiovascular diseases.

A Review on Current Aspects of Curcumin-Based Effects in Relation to Neurodegenerative, Neuroinflammatory and Cerebrovascular Diseases

Curcumin is among the most well-studied natural substances, known for its biological actions within the central nervous system, its antioxidant and anti-inflammatory properties, and human health benefits. However, challenges persist in effectively utilising curcumin, addressing its metabolism and passage through the blood-brain barrier (BBB) in therapies targeting cerebrovascular diseases. Current challenges in curcumin's applications revolve around its effects within neoplastic tissues alongside the development of intelligent formulations to enhance its bioavailability. Formulations have been discovered including curcumin's complexes with brain-derived phospholipids and proteins, or its liposomal encapsulation. These novel strategies aim to improve curcumin's bioavailability and stability, and its capability to cross the BBB, thereby potentially enhancing its efficacy in treating cerebrovascular diseases. In summary, this review provides a comprehensive overview of molecular pathways involved in interactions of curcumin and its metabolites, and brain vascular homeostasis. This review explores cellular and molecular current aspects, of curcumin-based effects with an emphasis on curcumin's metabolism and its impact on pathological conditions, such as neurodegenerative diseases, schizophrenia, and cerebral angiopathy. It also highlights the limitations posed by curcumin's poor bioavailability and discusses ongoing efforts to surpass these impediments to harness the full therapeutic potential of curcumin in neurological disorders.

Pathways to therapy resistance: The sheltering effect of the bone marrow microenvironment to multiple myeloma cells

Multiple Myeloma (MM) is a malignant expansion of plasma cells in the bone marrow (BM), resulting in a disease characterized by symptoms of end organ damage from light chain secretion, crowding of the BM, and bone lesions. Although the past two decades have been characterized by numerous novel therapies emerging, the disease remains incurable due to intrinsic or acquired drug resistance. A major player in MM's drug resistance arises from its intimate relationship with the BM microenvironment (BMME). Through stress-inducing conditions, soluble messengers, and physical adhesion to BM elements, the BMME activates numerous pathways in the myeloma cell. This not only propagates myeloma progression through survival and growth signals, but also specific mechanisms to circumvent therapeutic actions. In this review, we provide an overview of the BMME, the role of individual components in MM survival, and various therapy-specific resistance mechanisms reported in the literature.

The role and therapeutic potential of nuclear factor κB (NF-κB) in ischemic stroke

Stroke is a prevalent cerebrovascular condition with a global impact, causing significant rates of illness and death. Despite extensive research, the available treatment options for stroke remain restricted. Hence, it is crucial to gain a deeper understanding of the molecular mechanisms associated with the onset and advancement of stroke in order to establish a theoretical foundation for novel preventive and therapeutic approaches. NF-κB, also known as nuclear factor κB, is a transcription factor responsible for controlling the expression of numerous genes and plays a crucial role in diverse physiological processes. NF-κB is triggered and regulates neuroinflammation and other processes after stroke, promoting the generation of cytokine storms and contributing to the advancement of ischemic stroke (IS). Therefore, NF-κB could potentially play a vital role in stroke by regulating diverse pathophysiological processes. This review provides an overview of the functions of NF-κB in stroke and its governing mechanisms. In addition, our attention is directed towards various potential therapies that aim to inhibit the NF-κB signaling pathway in order to offer valuable insights for the advancement of innovative treatment approaches for stroke.

Mechanisms of immune response and cell death in ischemic stroke and their regulation by natural compounds

Ischemic stroke (IS), which is the third foremost cause of disability and death worldwide, has inflammation and cell death as its main pathological features. IS can lead to neuronal cell death and release factors such as damage-related molecular patterns, stimulating the immune system to release inflammatory mediators, thereby resulting in inflammation and exacerbating brain damage. Currently, there are a limited number of treatment methods for IS, which is a fact necessitating the discovery of new treatment targets. For this review, current research on inflammation and cell death in ischemic stroke was summarized. The complex roles and pathways of the principal immune cells (microglia, astrocyte, neutrophils, T lymphocytes, and monocytes/macrophage) in the immune system after IS in inflammation are discussed. The mechanisms of immune cell interactions and the cytokines involved in these interactions are summarized. Moreover, the cell death mechanisms (pyroptosis, apoptosis, necroptosis, PANoptosis, and ferroptosis) and pathways after IS are explored. Finally, a summary is provided of the mechanism of action of natural pharmacological active ingredients in the treatment of IS. Despite significant recent progress in research on IS, there remain many challenges that need to be overcome.

Biomedical applications of artificial exosomes for intranasal drug delivery

Intranasal administration offers a feasible, non-invasive method of delivering therapeutic drugs to the brain, allowing therapeutic pharmaceuticals to be administered directly to the central nervous system by bypassing the blood-brain barrier. Furthermore, exosomes are naturally occurring cell-derived nanovesicles that can serve as carriers for a variety of chemical compounds. Many studies have focused on artificial exosomes as innovative medication delivery methods. As a result, trans-nasal delivery of artificial exosomes might be employed to treat brain illnesses in a novel method. This review will outline the drug delivery mechanism of artificial extracellular vesicles, emphasize its advantages as a nasal drug carrier, particularly its application as a novel nanocarriers in brain diseases, and focus on its prospective application in chronic inflammatory nose disorders. Finally, artificial exosomes may become a unique drug delivery mode for clinical therapeutic usage.

Crosstalk between oxidative stress and neutrophil response in early ischemic stroke: a comprehensive transcriptome analysis

Background

Ischemic stroke (IS) is the second leading cause of mortality worldwide, continuing to be a serious health concern. It is well known that oxidative stress and neutrophil response play vital roles in the pathophysiology of early IS. However, the complex interactions and critical genes associated with them have not been fully understood.

Methods

Two datasets (GSE37587 and GSE16561) from the Gene Expression Omnibus database were extracted and integrated as the discovery dataset. Subsequent GSVA and WGCNA approaches were used to investigate IS-specific oxidative stress-related genes (ISOSGS). Then, we explored IS-specific neutrophil-associated genes (ISNGS) using CIBERSORT analysis. Next, the protein-protein interaction network was established to ascertain candidate critical genes related with oxidative stress and neutrophil response. Furthermore, these candidate genes were validated using GSE58294 dataset and our clinical samples by RT-qPCR method. Finally, functional annotation, diagnostic capability evaluation and drug-gene interactions were performed by using GSEA analysis, ROC curves and DGIDB database.

Result

In our analysis of discovery dataset, 155 genes were determined as ISOSGS and 559 genes were defined as ISNGS. Afterward, 9 candidate genes were identified through the intersection of ISOSGS and ISNGS, PPI network construction, and filtration by degree algorithm. Then, six real critical genes, including STAT3, MMP9, AQP9, SELL, FPR1, and IRAK3, passed the validation using the GSE58294 dataset and our clinical samples. Further functional annotation analysis indicated these critical genes were associated with neutrophil response, especially neutrophil extracellular trap. Meanwhile, they had a good diagnostic performance. Lastly, 53 potential drugs targeting these genes were predicted by DGIDB database.

Conclusion

We identified 6 critical genes, STAT3, FPR1, AQP9, SELL, MMP9 and IRAK3, related to oxidative stress and neutrophil response in early IS, which may provide new insights into understanding the pathophysiological mechanism of IS. We hope our analysis could help develop novel diagnostic biomarkers and therapeutic strategies for IS.

Ginkgolide C attenuates cerebral ischemia/reperfusion-induced inflammatory impairments by suppressing CD40/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. (Ginkgoaceae), a traditional Chinese medicine, has been applied for thousands of years for the treatment of cardio-cerebral vascular diseases in China. It is written in Compendium of Materia Medica that Ginkgo has the property of "dispersing poison", which is now referred to as anti-inflammatory and antioxidant. Ginkgolides are important active ingredients in Ginkgo biloba leaves and ginkgolide injection has been frequently applied in clinical practice for the treatment of ischemic stroke. However, few studies have explored the effect and mechanism of ginkgolide C (GC) with anti-inflammatory activity in cerebral ischemia/reperfusion injury (CI/RI).

AIM OF THE STUDY

The present study aimed to demonstrate whether GC was capable of attenuating CI/RI. Furthermore, the anti-inflammatory effect of GC in CI/RI was explored around the CD40/NF-κB pathway.

MATERIALS AND METHODS

In vivo, middle cerebral artery occlusion/reperfusion (MCAO/R) model was established in rats. The neuroprotective effect of GC was assessed by neurological scores, cerebral infarct rate, microvessel ultrastructure, blood-brain barrier (BBB) integrity, brain edema, neutrophil infiltration, and levels of TNF-α, IL-1β, IL-6, ICAM-1, VCAM-1, and iNOS. In vitro, rat brain microvessel endothelial cells (rBMECs) were preincubated in GC before hypoxia/reoxygenation (H/R) culture. The cell viability, levels of CD40, ICAM-1, MMP-9, TNF-α, IL-1β, and IL-6, and activation of NF-κB pathway were examined. In addition, the anti-inflammatory effect of GC was also investigated by silencing CD40 gene in rBMECs.

RESULTS

GC attenuated CI/RI as demonstrated by decreasing neurological scores, reducing cerebral infarct rate, improving microvessel ultrastructural features, ameliorating BBB disruption, attenuating brain edema, inhibiting MPO activity, and downregulating levels of TNF-α, IL-1β, IL-6, ICAM-1, VCAM-1, and iNOS. Coherently, in rBMECs exposed to H/R GC enhanced cell viability and downregulated levels of ICAM-1, MMP-9, TNF-α, IL-1β, and IL-6. Furthermore, GC suppressed CD40 overexpression and hindered translocation of NF-κB p65 from the cytosol to the nucleus, phosphorylation of IκB-α, and activation of IKK-β in H/R rBMECs. However, GC failed to protect rBMECs from H/R-induced inflammatory impairments and suppress activation of NF-κB pathway when CD40 gene was silenced.

CONCLUSIONS

GC attenuates cerebral ischemia/reperfusion-induced inflammatory impairments by suppressing CD40/NF-κB pathway, which may provide an available therapeutic drug for CI/RI.

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.

Curcumin protects against cerebral ischemia-reperfusion injury in rats by attenuating oxidative stress and inflammation: a meta-analysis and mechanism exploration

Accumulating evidence has suggested that curcumin may protect against cerebral ischemia-reperfusion injury (CIRI). However, biological mechanisms vary across studies, limiting the clinical applicability of these findings. We performed a meta-analysis on publications evaluating curcumin administration in rat models of CIRI. Furthermore, we sought to test the hypothesis that curcumin alleviates CIRI through diminishing oxidation and inflammation. We searched PubMed, Embase, Web of Science, and Cochrane from the starting date of each database to May 2022 for experimental rat studies exploring the use of curcumin after ischemia reperfusion. Included articles were assessed for bias using SYRCLE's risk of bias tool. Data were aggregated by a random effects model. Curcumin administration significantly reduced neurological deficit score (20 studies; pooled mean difference [MD] = -1.57; 95% CI, -1.78 to -1.36, P < .00001), infarct volume (18 studies; pooled MD = -17.56%; 95% CI, -20.92% to -14.20%; P < 0.00001), and brain water content (8 studies, pooled MD = -11.29%, 95% CI: -16.48%, -6.11%, P < .00001). Compared with control, the levels of superoxide dismutase, glutathione, and glutathione peroxidase were significantly higher, whereas the levels of reactive oxygen species, malondialdehyde, interleukin-1β, interleukin-6, interleukin-8, and nuclear factor kappa B were significantly lower (P < .05). Subgroup analysis raised the possibility that intervention affections differed by curcumin's dose. To our knowledge, this is the first meta-analysis of curcumin's neuroprotection and mechanisms in rat CIRI models. Our analysis suggests the neuroprotective potential of curcumin in CIRI via antioxidant activity and anti-inflammatory effect. More research is required to further confirm the effectiveness and safety of curcumin on ischemic stroke therapy.

Stem Cell-derived Extracellular Vesicles: A Promising Nano Delivery Platform to the Brain?

A very important cause of the frustration with drug therapy for central nervous system (CNS) diseases is the failure of drug delivery. The blood-brain barrier (BBB) prevents most therapeutic molecules from entering the brain while maintaining CNS homeostasis. Scientists are keen to develop new brain drug delivery systems to solve this dilemma. Extracellular vesicles (EVs), as a class of naturally derived nanoscale vesicles, have been extensively studied in drug delivery due to their superior properties. This review will briefly present current brain drug delivery strategies, including invasive and non-invasive techniques that target the brain, and the application of nanocarriers developed for brain drug delivery in recent years, especially EVs. The cellular origin of EVs affects the surface protein, size, yield, luminal composition, and other properties of EVs, which are also crucial in determining whether EVs are useful as drug carriers. Stem cell-derived EVs, which inherit the properties of parental cells and avoid the drawbacks of cell therapy, have always been favored by researchers. Thus, in this review, we will focus on the application of stem cell-derived EVs for drug delivery in the CNS. Various nucleic acids, proteins, and small-molecule drugs are loaded into EVs with or without modification and undergo targeted delivery to the brain to achieve their therapeutic effects. In addition, the challenges facing the clinical application of EVs as drug carriers will also be discussed. The directions of future efforts may be to improve drug loading efficiency and precise targeting.

Curcumin Ameliorates Neurobehavioral Deficits in Ambient Dusty Particulate Matter-Exposure Rats: The Role of Oxidative Stress

It has been consistently found that exposure to ambient air pollution, such as particulate matter (PM), results in cognitive impairments and mental disorders. This study aimed to investigate the possible neuroprotective effects of curcumin, a polyphenol compound, on the neurobehavioral deficits and to identify the role of oxidative stress in dusty PM exposure rats. Rats received curcumin (50 mg/kg, daily, gavage, 2 weeks) 30 min before placing animals in a clean air chamber (≤ 150 µg/m³, 60 min daily, 2 weeks) or ambient dusty PM chamber (2000-8000 µg/m³, 60 min daily, 2 weeks). Subsequently, the cognitive and non-cognitive functions of the animals were evaluated using standard behavioral tests. Moreover, blood-brain barrier (BBB) permeability, brain water content (BWC), oxidative-antioxidative status, and histological changes were determined in the cerebral cortex and hippocampal areas of the rats. Our results showed that curcumin administration in dusty PM exposure rats attenuates memory impairment, decreases anxiety-/depression-like behaviors, and improves locomotor/exploratory activities. These findings were accompanied by reduced BBB permeability and BWC, decreasing oxidative stress, and lessening neuronal loss in the cerebral cortex and different hippocampal areas. The results of this study suggest that curcumin's antioxidant properties may contribute to its efficacy in improving neurobehavioral deficits and preventing neuronal loss associated with dusty PM exposure.

Leucine mediates cognitive dysfunction in early life stress-induced mental disorders by activating autophagy

Objectives

To explore the relationship between leucine in cerebrospinal fluid (CSF) and cognitive dysfunction in rats with early life stress (ELS) induced mental illness, and pathophysiological mechanism involved.

Methods

The maternal separation (MS), an animal paradigm used widely as a preclinical model of ELS which is one of the important risk factors for mental disorders. Behavioral experiments including open-field test, sucrose preference, object recognition and Morris water maze tests, Nissl staining, transmission electron microscopy and WES were employed in the present study.

Results

The behavioral results showed that MS rats were more prone to cognitive impairment and depression-and-anxiety-like behaviors than controls, including spatial self-exploration ability, memory ability, and spatial learning and memory function. Nissl staining analysis indicated that the number of neurons in the CA1 and CA3 regions of the hippocampus significantly decreased and the arrangement of nerve cells was abnormal. The leucine levels were decreased in the CSF of MS rats and highly correlated with the number of hippocampal neurons, and yet leucine supplementation improved the degree of MS-induced cognitive impairment. Furthermore, there were autophagosomes in the hippocampus of the low-leucine diet rats of the control and MS group but not in the high-leucine diet MS group by transmission electron microscopy. The protein expression of Beclin-1 in the hippocampus was significantly increased in the MS normal diet group and MS low-leucine diet group, yet decreased in the MS high-leucine diet group compared with the MS low-leucine diet group. Meanwhile, the Bcl-2/Bax ratio was significantly decreased in the control low-leucine diet group, MS normal diet group and MS low-leucine diet group. Ultimately, in vitro experiments suggested that leucine deficiency could activate neuronal autophagy including enhanced LC3II/LC3I and mRFP-GFP-LC3, which was consistent with the in vivo results, and the cell apoptosis rate and lactate dehydrogenase (LDH) cytotoxicity were also increased with leucine deficiency, while the above effects could be partly reversed by autophagy inhibitor treatment.

Conclusions

MS model caused adult male rats to be susceptible to cognitive dysfunction, which may regulate autophagy in hippocampal neurons through leucine metabolism in CSF.

Network pharmacology approach to investigate the multitarget mechanisms of Zhishi Rhubarb Soup on acute cerebral infarction

CONTEXT

Zhishi Rhubarb Soup (ZRS) is a traditional Chinese medicine formula used in the clinic to treat acute cerebral infarction (ACI) for many years. However, the exact mechanism of the treatment remains unclear.

OBJECTIVE

This study elucidates the multitarget mechanisms underlying the effects of ZRS on ACI using network pharmacology analysis and verify its effect by performing animal experiments.

MATERIALS AND METHODS

Using the network pharmacology approach, the multiple components, critical targets and potential mechanisms of ZRS against ACI were investigated. Six herbal names of ZRS and 'acute cerebral infarction' were used as keywords to search the relevant databases. In addition, we established the MCAO model to verify the results of network pharmacology enrichment analysis. ZRS (10 g crude drug/kg) was gavaged once per day for 7 consecutive days beginning 3 h after model establishment. After ZRS treatment, TTC staining, Western blot analysis, IHC and ELISA were conducted to further explore the mechanism of ZRS intervention in ACI.

RESULTS

The network pharmacology approach identified 69 key targets, 10 core genes and 169 signalling pathways involved in the treatment of ACI with ZRS. In vivo experiment showed that ZRS treatment significantly reduced cerebral infarction volume (42.76%). It also reduced the expression level of AGE, RAGE and P65; and inhibited the expression of inflammatory MMP-9 and IFN-γ.

CONCLUSIONS

This study demonstrated that ZRS improved cerebral ischaemic injury by inhibiting neuroinflammation partly via the AGE-RAGE signalling pathway. It provides a theoretical basis for the clinical application of ZRS in the treatment of ACI.

Neuroprotective Effect of Corosolic Acid Against Cerebral Ischemia-Reperfusion Injury in Experimental Rats

Several therapeutic approaches were also urgently needed as ischaemic stroke was one of the most common brain disorders. Many phytochemicals have recently been discovered for the advancement of lead-like libraries that are concentrated on the peripheral and central nervous systems. Science does not yet understand how these drugs work, nor do they comprehend their in vivo characteristics. We investigated the potential benefits of corosolic acid (CA) in the treatment of brain injury caused by ischemia/reperfusion (I/R) in adult male Sprague-Dawley rats. Injury occurs after a 2-hour transient occlusion of the posterior cerebral artery and subsequent reperfusion (after 20 hours). Furthermore, the experiment assessed the size of the infarct, the amount of brain water present, as well as the neurofunctional conditions in rats. In the study, several markers of inflammation and cytokines associated with brain injury were measured. The Elisa kit was used in this study to measure the mRNA expression of interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin 1β, TNF-α (tumor necrosis factor), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and nitrous oxide (NO). The CA treatment significantly reduced brain water content, brain infarction volume, neurological scores, and Evans blue leakage (p < 0.001 and p < 0.001). Experimental rats were treated with CA after a significantly reduced level of anti-inflammatory, pro-inflammatory, and oxidative stress mediators was noted in their body tissues and serum (p < 0.001). By suppressing inflammatory responses in rats, CA demonstrated anti-inflammatory and neuroprotective properties.

The action of curcumin against damage resulting from cerebral stroke: a systematic review

Stroke is the second leading cause of morbidity and mortality globally. Treatments for stroke are limited, and preventive treatments are scarce. Curcumin (CUR) has several biological effects, as described in the literature, which highlight its antioxidant and neuroprotective effects. Therefore, this qualitative systematic review aimed to investigate the effects of CUR on damage caused by stroke in rodent models. A systematic search was performed on three databases PubMed, Scopus, and Web of Science. In addition, the risk-of-bias and quality of the studies were assessed using SYRCLE and Collaborative Approach for Meta-Analysis and Review of Animal Data from Experimental Studies, respectively. The selection, inclusion, and exclusion criteria were established by the authors. At the end of our systematic search of the three databases, we found a total of 728 articles. After excluding duplicates and triplicates and reading the abstracts, keywords, and full texts, 53 articles were finally included in this systematic review. CUR exerts several beneficial effects against the damage caused by both ischemic and hemorrhagic stroke, via different pathways. However, because of its low bioavailability, Free-form CUR only exerted significant effects when it was administered at high concentrations. In contrast, when CUR was administered using nanostructured systems, positive responses were observed even at low concentrations. The mechanisms of action of CUR, free or in nanostructure, are extremely important for the recovery of injured brain tissue after a stroke; CUR has neuroprotective, antioxidant, anti-inflammatory, and anti-apoptotic effects and helps to maintain the integrity of the blood-brain barrier. Finally, we concluded that CUR presents an extremely important and significant response profile against the damage caused by stroke, making it a possible therapeutic candidate for individuals affected by this disease.

Polyphenols for the Treatment of Ischemic Stroke: New Applications and Insights

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Currently, the main therapeutic strategy involves the use of intravenous thrombolysis to restore cerebral blood flow to prevent the transition of the penumbra to the infarct core. However, due to various limitations and complications, including the narrow time window in which this approach is effective, less than 10% of patients benefit from such therapy. Thus, there is an urgent need for alternative therapeutic strategies, with neuroprotection against the ischemic cascade response after IS being one of the most promising options. In the past few decades, polyphenolic compounds have shown great potential in animal models of IS because of their high biocompatibility and ability to target multiple ischemic cascade signaling pathways, although low bioavailability is an issue that limits the applications of several polyphenols. Here, we review the pathophysiological changes following cerebral ischemia and summarize the research progress regarding the applications of polyphenolic compounds in the treatment of IS over the past 5 years. Furthermore, we discuss several potential strategies for improving the bioavailability of polyphenolic compounds as well as some essential issues that remain to be addressed for the translation of the related therapies to the clinic.

Curcuminoids for Metabolic Syndrome: Meta-Analysis Evidences Toward Personalized Prevention and Treatment Management

The metabolic syndrome (MS) is a multifactorial syndrome associated with a significant economic burden and healthcare costs. MS management often requires multiple treatments (polydrug) to ameliorate conditions such as diabetes mellitus, insulin resistance, obesity, cardiovascular diseases, hypertension, and non-alcoholic fatty liver disease (NAFLD). However, various therapeutics and possible drug-drug interactions may also increase the risk of MS by altering lipid and glucose metabolism and promoting weight gain. In addition, the medications cause side effects such as nausea, flatulence, bloating, insomnia, restlessness, asthenia, palpitations, cardiac arrhythmias, dizziness, and blurred vision. Therefore, is important to identify and develop new safe and effective agents based on a multi-target approach to treat and manage MS. Natural products, such as curcumin, have multi-modalities to simultaneously target several factors involved in the development of MS. This review discusses the recent preclinical and clinical findings, and up-to-date meta-analysis from Randomized Controlled Trials regarding the effects of curcumin on MS, as well as the metabonomics and a pharma-metabolomics outlook considering curcumin metabolites, the gut microbiome, and environment for a complementary personalized prevention and treatment for MS management.

Mechanisms Underlying Curcumin-Induced Neuroprotection in Cerebral Ischemia

Ischemic stroke is the leading cause of death and disability worldwide, and restoring the blood flow to ischemic brain tissues is currently the main therapeutic strategy. However, reperfusion after brain ischemia leads to excessive reactive oxygen species production, inflammatory cell recruitment, the release of inflammatory mediators, cell death, mitochondrial dysfunction, endoplasmic reticulum stress, and blood-brain barrier damage; these pathological mechanisms will further aggravate brain tissue injury, ultimately affecting the recovery of neurological functions. It has attracted the attention of researchers to develop drugs with multitarget intervention effects for individuals with cerebral ischemia. A large number of studies have established that curcumin plays a significant neuroprotective role in cerebral ischemia via various mechanisms, including antioxidation, anti-inflammation, anti-apoptosis, protection of the blood-brain barrier, and restoration of mitochondrial function and structure, restoring cerebral circulation, reducing infarct volume, improving brain edema, promoting blood-brain barrier repair, and improving the neurological functions. Therefore, summarizing the results from the latest literature and identifying the potential mechanisms of action of curcumin in cerebral ischemia will serve as a basis and guidance for the clinical applications of curcumin in the future.

Knockdown of circRNA-Memo1 Reduces Hypoxia/Reoxygenation Injury in Human Brain Endothelial Cells Through miRNA-17-5p/SOS1 Axis

Circ-Memo1 has been proved to be upregulated in ischemia-reperfusion induced acute injury of kidney tissues. However, the potential role of circ-Memo1 in cerebral hypoxia/reoxygenation (H/R) injury is still unclear.Blood samples were collected from 25 ischemic stroke patients and 25 healthy controls. To construct the H/R model, human brain microvascular endothelial cells (HBMVECs) were cultured under the hypoxic condition, followed by reoxygenation. Cell viability was analyzed by MTT assay. Flow cytometry was carried out to examine cell apoptosis. The level of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were measured by MDA and SOD assay kits, respectively. The levels of TNF-α, IL-1β, and IL-6 were determined by enzyme-linked immunosorbent assay (ELISA). Dual-luciferase reporter gene detection was employed to verify the binding relationships between circ-Memo1, miR-17-5p, and SOS1.Circ-Memo1 and SOS1 expressions were increased, and miR-17-5p expression was reduced in ischemic stroke patients. Circ-Memo1 silencing promoted cell viability, inhibited the activation of ERK/NF-κB signaling pathway, reduced oxidative stress and inflammatory response, and inhibited cell apoptosis. Moreover, miR-17-5p functioned as the sponge of circ-Memo1, and SOS1 was identified as the target of miR-17-5p. The protective effect of circ-Memo1 knockdown on cell injury after H/R treatment was weakened by miR-17-5p inhibition.Knockdown of circ-Memo1 alleviated H/R injury of HBMVEC cells by regulating the miR-17-5p/SOS1 axis, indicating that circ-Memo1 might be a potential treatment target for cerebral H/R injury.

The natural (poly)phenols as modulators of microglia polarization via TLR4/NF-κB pathway exert anti-inflammatory activity in ischemic stroke

Increasing evidences suggest that inflammation plays a key role in the pathogenesis of stroke, a devastating disease second only to cardiac ischemia as a cause of death worldwide. Microglia are the first non-neuronal cells on the scene during the innate immune response to acute ischemic stroke. Microglia respond to acute brain injury by activating and developing classic M1-like (pro-inflammatory) or alternative M2-like (anti-inflammatory) phenotypes. M1 microglia produce pro-inflammatory cytokines to exacerbate neural death, astrocyte apoptosis, and blood brain barrier (BBB) disruption, while M2 microglia play the opposite role. NF-κB, a central regulator of the inflammatory response, was responsible for microglia M1 and M2 polarization. NF-κB p65 and p50 form a heterodimer to initiate a pro-inflammatory cytokine response, which enhances M1 activation and impair M2 response of microglia. TLR4, expressed on the surface of microglia, plays an important role in activating NF-κB, ultimately causing the M1 response of microglia. Therefore, modulation of microglial phenotypes via TLR4/NF-κB signaling pathway may be a promising therapeutic approach for ischemic stroke. Dietary (poly)phenols are present in various foods, which have shown promising protective effects on ischemic stroke. In vivo studies strongly suggest that many (poly)phenols have a pronounced impact on ischemic stroke, as demonstrated by lower neuroinflammation. Thus, this review focuses on the anti-inflammatory properties of dietary (poly)phenols and discusses their effects on the polarization of microglia through modulating TLR4/NF-κB signaling pathway in the ischemic stroke.

Nafamostat protects against early brain injury after subarachnoid hemorrhage in mice

This study aimed to evaluate the effects of nafamostat, a serin protease inhibitor, in the management of subarachnoid hemorrhage (SAH). SAH was induced by endovascular perforation in male mice. Nafamostat was administered intraperitoneally four times immediately after SAH induction. Cerebral blood flow, neurological behavior tests, SAH grade and protein expression were evaluated at 24 h after SAH induction. In the in vitro model, human brain microvascular endothelial cells (HBMVECs), HBVECs were exposed to thrombin and hypoxia for 24 h; nafamostat was administered and the protein expression was evaluated. Eighty-eight mice were included in the in vivo study. Fifteen mice (17%) were excluded because of death or procedure failure. Nafamostat exerted no significant effect on the SAH grade or cerebral blood flow; however, it improved the neurological behavior and suppressed the thrombin and MMP-9 expression. In addition, nafamostat suppressed the ICAM-1 expression and p38 phosphorylation in the in vitro study. Nafamostat has a protective effect against HBMVEC after exposure to thrombin and hypoxia, suggesting its role in improving the neurological outcomes after SAH. These findings indicate that nafamostat has the potential to be a novel therapeutic drug in the management of SAH.

Lupinus albus Protein Components Inhibit MMP-2 and MMP-9 Gelatinolytic Activity In Vitro and In Vivo

Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are regarded as important clinical targets due to their nodal-point role in inflammatory and oncological diseases. Here, we aimed at isolating and characterizing am MMP-2 and-9 inhibitor (MMPI) from Lupinus albus and at assessing its efficacy in vitro and in vivo. The protein was isolated using chromatographic and 2-D electrophoretic procedures and sequenced by using MALDI-TOF TOF and MS/MS analysis. In vitro MMP-2 and 9 inhibitions were determined on colon adenocarcinoma (HT29) cells, as well as by measuring the expression levels of genes related to these enzymes. Inhibitory activities were also confirmed in vivo using a model of experimental TNBS-induced colitis in mice, with oral administrations of 15 mg·kg^-1. After chromatographic and electrophoretic isolation, the L. albus MMP-9 inhibitor was found to comprise a large fragment from δ-conglutin and, to a lower extent, small fragments of β-conglutin. In vitro studies showed that the MMPI successfully inhibited MMP-9 activity in a dose-dependent manner in colon cancer cells, with an IC50 of 10 µg·mL^-1 without impairing gene expression nor cell growth. In vivo studies showed that the MMPI maintained its bioactivities when administered orally and significantly reduced colitis symptoms, along with a very significant inhibition of MMP-2 and -9 activities. Overall, results reveal a novel type of MMPI in lupine that is edible, proteinaceous in nature and soluble in water, and effective in vivo, suggesting a high potential application as a nutraceutical or a functional food in pathologies related to abnormally high MMP-9 activity in the digestive system.

Neuroprotective and Anti-Inflammatory Effect of Pterostilbene Against Cerebral Ischemia/Reperfusion Injury via Suppression of COX-2

Background: The incidence of cerebral ischemia disease leading cause of death in human population worldwide. Treatment of cerebral ischemia remains a clinical challenge for researchers and mechanisms of cerebral ischemia remain unknown. During the cerebral ischemia, inflammatory reaction and oxidative stress plays an important role. The current investigation scrutinized the neuroprotective and anti-inflammatory role of pterostilbene against cerebral ischemia in middle cerebral artery occlusion (MCAO) rodent model and explore the underlying mechanism.

Methods: The rats were divided into following groups viz., normal, sham, MCAO and MCAO + pterostilbene (25 mg/kg) group, respectively. The groups received the oral administration of pterostilbene for 30 days followed by MCAO induction. The neurological score, brain water content, infarct volume and Evan blue leakage were estimated. Hepatic, renal, heart, inflammatory cytokines and inflammatory mediators were estimated.

Results: Pterostilbene treatment significantly (p < 0.001) improved the body weight and suppressed the glucose level and brain weight. Pterostilbene significantly (p < 0.001) reduced the hepatic, renal and heart parameters. Pterostilbene significantly (p < 0.001) decreased the level of glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and decreased the level of malonaldehyde (MDA), 8-Hydroxy-2′-deoxyguanosine (8-OHdG). Pterostilbene significantly (p < 0.001) inflammatory cytokines and inflammatory parameters such as cyclooxygenase-2 (COX-2), inducible nitric oxidase synthase (iNOS) and prostaglandin (PGE₂). Pterostilbene significantly (p < 0.001) down-regulated the level of metalloproteinases (MMP) such as MMP-2 and MMP-9. Pterostilbene suppressed the cellular swelling, cellular disintegration, macrophage infiltration, monocyte infiltration and polymorphonuclear leucocyte degranulation in the brain.

Conclusion: In conclusion, Pterostilbene exhibited the neuroprotective effect against cerebral ischemia in rats via anti-inflammatory mechanism.

The Role of Supplementation with Natural Compounds in Post-Stroke Patients

Malnutrition is a serious problem in post-stroke patients. Importantly, it intensifies with hospitalization, and is related to both somatic and psychological reasons, as well as is associated with the insufficient knowledge of people who accompany the patient. Malnutrition is a negative prognostic factor, leading to a reduction in the quality of life. Moreover, this condition significantly extends hospitalization time, increases the frequency of treatment in intensive care units, and negatively affects the effectiveness of rehabilitation. Obtaining growing data on the therapeutic effectiveness of new compounds of natural origin is possible through the use of pharmacodynamic and analytical methods to assess their therapeutic properties. The proper supply of nutrients, as well as compounds of natural origin, is an important element of post-stroke therapy, due to their strong antioxidant, anti-inflammatory, neuroprotective and neuroplasticity enhancing properties. Taking the above into account, in this review we present the current state of knowledge on the benefits of using selected substances of natural origin in patients after cerebral stroke.

Neuroprotective Effects of Curcumin in Cerebral Ischemia: Cellular and Molecular Mechanisms

Despite being a major global health concern, cerebral ischemia/stroke has limited therapeutic options. Tissue plasminogen activator (tPA) is the only available medication to manage acute ischemic stroke, but this medication is associated with adverse effects and has a narrow therapeutic time window. Curcumin, a polyphenol that is abundantly present in the rhizome of the turmeric plant (Curcuma longa), has shown promising neuroprotective effects in animal models of neurodegenerative diseases, including cerebral ischemia. In the central nervous system (CNS), neuroprotective effects of curcumin have been experimentally validated in Alzheimer's disease, Parkinson's disease, multiple sclerosis, and cerebral ischemia. Curcumin can exert pleiotropic effects in the postischemic brain including antioxidant, anti-inflammatory, antiapoptotic, vasculoprotective, and direct neuroprotective efficacies. Importantly, neuroprotective effects of curcumin has been reported in both ischemic and hemorrhagic stroke models. A broad-spectrum neuroprotective efficacy of curcumin suggested that curcumin can be an appealing therapeutic strategy to treat cerebral ischemia. In this review, we aimed to address the pharmacotherapeutic potential of curcumin in cerebral ischemia including its cellular and molecular mechanisms of neuroprotection revealing curcumin as an appealing therapeutic candidate for cerebral ischemia.

Natural Products in the Prevention of Metabolic Diseases: Lessons Learned from the 20th KAST Frontier Scientists Workshop

The incidence of metabolic and chronic diseases including cancer, obesity, inflammation-related diseases sharply increased in the 21st century. Major underlying causes for these diseases are inflammation and oxidative stress. Accordingly, natural products and their bioactive components are obvious therapeutic agents for these diseases, given their antioxidant and anti-inflammatory properties. Research in this area has been significantly expanded to include chemical identification of these compounds using advanced analytical techniques, determining their mechanism of action, food fortification and supplement development, and enhancing their bioavailability and bioactivity using nanotechnology. These timely topics were discussed at the 20th Frontier Scientists Workshop sponsored by the Korean Academy of Science and Technology, held at the University of Hawaii at Manoa on 23 November 2019. Scientists from South Korea and the U.S. shared their recent research under the overarching theme of Bioactive Compounds, Nanoparticles, and Disease Prevention. This review summarizes presentations at the workshop to provide current knowledge of the role of natural products in the prevention and treatment of metabolic diseases.

Curcumin ameliorates ischemic stroke injury in rats by protecting the integrity of the blood-brain barrier

The blood-brain barrier (BBB) is critical for proper cerebral homeostasis and its dysfunction during ischemic stroke can result in significant neurological injury. The major goal of the present study was to identify whether curcumin pretreatment possessed protective effects on BBB integrity during the 24 h of acute ischemic brain injury. To investigate the protective effects of curcumin, male Sprague-Dawley rats were divided into multiple groups, including sham, middle cerebral artery occlusion/reperfusion (MCAO/R) vehicle and curcumin pretreated MCAO/R groups. The effects of curcumin were measured by analyzing neurological deficits, infarct size, BBB permeability and expression levels of permeability-related proteins in the brain. It was found that curcumin pretreatment significantly improved neurological scores, decreased infarct size, and protected synaptic remodeling of hippocampal neurons and upregulated the protein expression level of tight junction proteins, ZO-1, occludin and claudin-5 in ischemic rat brains. Furthermore, curcumin pretreatment before stroke was shown to downregulate the phosphorylation of NF-κB and MMP-9, which are central mediators of inflammation. The results from the present study indicated that curcumin pretreatment ameliorated ischemic stroke injury by protecting BBB integrity and synaptic remodeling, as well as inhibiting inflammatory responses.

Borneol-modified tanshinone IIA liposome improves cerebral ischemia reperfusion injury by suppressing NF-κB and ICAM-1 expression

OBJECTIVE

To investigate the metabolism and brain tissue distribution of borneol-modified tanshinone IIA liposome (BO-TA-Lip) and its effect on NF-κB and ICAM-1 in cerebral ischemia reperfusion rats, thereby exploring the ameliorative mechanism of BO-TA-Lip on ischemic encephalopathy.

METHODS

Particle size, entrapment efficiency, drug loading were measured to evaluate the preparation comprehensively. Metabolism and brain tissue distributions in vivo were measured by HPLC, and the pharmacokinetic parameters were calculated. In addition, 24 SD rats were randomly divided into sham, model, STS (sodium tanshinone IIA sulfonate, 30 mg/kg) and BO-TA-Lip groups (44 mg/kg). The middle cerebral artery occlusion (MCAO) rats were constructed with thread embolism method. Neurological deficits were scored using Zea Longa scoring standard. TTC and HE staining were used for the cerebral infarction and histopathological examination, respectively. The protein expression was examined by immunohistochemistry and Western blot.

RESULTS

The average particle size, encapsulation efficiency and drug loading of BO-TA-Lip were (135.33 ± 7.25) nm, (85.95 ± 3.20)% and (4.06 ± 0.31)%, respectively. Both in the pharmacokinetic analysis of plasma and brain tissue, in BO-TA-Lip group, the peak concentration and the area under the curve increased, and the clearance rate decreased. The neurological deficit scores and infarct area of the BO-TA-Lip group were significantly lower than that of the model and STS groups. Besides, BO-TA-Lip reduced the protein expression of NF-κB, ICAM-1, IL-1β, TNF-α and IL-6 in the brain tissue.

CONCLUSION

BO-TA-Lip had higher bioavailability and better absorption in brain tissue, and could improve cerebral ischemia reperfusion injury, which might be related to the inhibitory effect of BO-TA-Lip in expression of NF-κB and ICAM-1.

Effect of curcuma on zinc, lipid profile and antioxidants levels in blood and tissue of streptozotocin-induced diabetic rats fed zinc deficiency diet

Due to the importance of zinc as an antioxidant and its crucial role in insulin synthesis, its deficiency may affect adversely diabetic state. So, this study aimed to modulate these effects using Curcuma longa as natural antioxidant. Rats were divided into four groups: two groups fed a zinc sufficient diet one non-diabetic and the other diabetic, while the others two groups diabetic rats fed a zinc-deficient diet, one non-treated group and the other treated with curcuma 1% diet. After four weeks of dietary manipulation, fasting animals were scarified. Zinc deficiency decreased body weight, insulin, zinc tissues, alkaline phosphatase, reduced glutathione, glutathione peroxidase, superoxide dismutase and catalase. Conversely glucose, lipids profile, transaminases and malondialdehyde were increased. However, the above-mentioned parameters were significantly improved following curcuma supplementation. So it seems that curcuma is a potent factor for reducing the oxidative severity of zinc deficiency in experimental diabetes through its antioxidants actions.

Curcumin Modulates the Crosstalk Between Macrophages and Bone Mesenchymal Stem Cells to Ameliorate Osteogenesis

Bone healing is thought to be influenced by the cross-talk between bone forming and immune cells. In particular, macrophages play a crucial role in the regulation of osteogenesis. Curcumin, the major bioactive polyphenolic ingredient of turmeric, has been shown to regulate inflammatory response and osteogenic activities. However, whether curcumin could regulate macrophage polarization and subsequently influence osteogenesis remain to be elucidated. In this study, the potential immunomodulatory capability of curcumin on inflammatory response and phenotype switch of macrophages and the subsequent impact on osteogenic differentiation of MSCs are investigated. We demonstrated that curcumin exhibited significant anti-inflammatory effect by polarizing the macrophages toward anti-inflammatory phenotype, with increased expression of IL-4, IL-10, and CD206, and decreased expression of IL-1β, TNF-α, CCR7, and iNOS. In addition, curcumin could improve the osteo-immune microenvironment via promoting osteogenesis-related regenerative cytokine BMP-2 and TGF-β production. Moreover, the co-cultured test of macrophages and BMSCs showed that curcumin-modulated macrophages conditioned medium could promote osteogenic differentiation of BMSCs with increased gene (ALP, Runx-2, OCN, and OPN) and protein (Runx-2 and OCN) expression levels, enhanced ALP activity, and obvious formation of mineralized nodules. Taken together, with the interaction between curcumin-conditioned macrophage and curcumin-stimulated BMSCs, curcumin could remarkably enhance the osteogenic differentiation of BMSCs in LPS-activated inflammatory macrophage-BMSCs coculture system.

Boeravinone B Protects Brain against Cerebral Ichemia Reperfusion Injury in Rats: Possible Role of Anti-inflammatory and Antioxidant

It is well known that inflammatory reactions and oxidative stress play a key role in the pathogenesis of cerebral ischemia and secondary injury. Boeravinone B (BB) proofed their anti-inflammatory and antioxidant effect, but their neuroprotective effects still unknown. In this experimental study, we explore the neuro-protective effect of Boeravinone B on the ischemia/reperfusion and explore the possible mechanism. Male Wistar rats were used for the current experimental study. First induces natural I/R injury in rats and treated with BB and nifedipine, respectively. Rats were subjected to ischemia after 6 consecutive days by occlusion of the bilateral common carotid arteries (BCCAO). Neurological score, biochemical, antioxidant, pro-inflammatory cytokines and inflammatory parameters were estimated in the serum and brain tissue. BB treatment significantly (p < 0.001) suppressed neuronal injury, dose-dependently decreased the cerebral water content. BB treatment altered the pro-inflammatory cytokines, antioxidant and inflammatory mediators in the serum and brain tissue. BB regulated the expression of glycine (Gly), glutamic acid (Glu), taurine (Tau), aspartic acid (Asp) and γ-aminobutyric acid (GABA) and enhanced the activity of Na+, K+ ATPase and Ca2+ ATPase. BB significantly (p < 0.001) reduced antioxidant enzymes such as glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), malondialdehyde (MDA), glutathione reductase (GR); inflammatory cytokines include interleukin-4 (IL-4), interleukin-1 (IL-1), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), interleukin-6 (IL-6) and interleukin-1β (IL-1β); inflammatory mediators include prostaglandin (PGE2), nuclear kappa factor B (NF-κB) and cyclooxygenase-2 (COX-2), respectively. In this study, we have found that Boeravinone B exhibited protection against cerebral I/R by reducing oxidative stress and inflammatory reaction.

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.

Photosensitizers attenuate LPS-induced inflammation: implications in dentistry and general health

Antimicrobial photodynamic therapy (aPDT) is a complementary therapeutic modality for periodontal and endodontic diseases, in which Gram-negative bacteria are directly involved. Currently, there are few evidences regarding the effects of aPDT on bacterial components such as lipopolysaccharide (LPS) and it would represent a major step forward in the clinical use of this therapy. In this context, this study aimed to evaluate the efficacy of different photosensitizers (PSs) used in aPDT in LPS inhibition. Four PSs were used in this study: methylene blue (MB), toluidine blue (TBO), new methylene blue (NMB), and curcumin (CUR). Different approaches to evaluate LPS interaction with PSs were used, such as spectrophotometry, Limulus amebocyte lysate (LAL) test, functional assays using mouse macrophages, and an in vivo model of LPS injection. Spectrophotometry showed that LPS decreased the absorbance of all PSs used, indicating interactions between the two species. LAL assay revealed significant differences in LPS concentrations upon pre-incubation with the different PSs. Interestingly, the inflammatory potential of LPS decreased after previous treatment with the four PSs, resulting in decreased secretion of inflammatory cytokines by macrophages. In vivo, pre-incubating curcumin with LPS prevented animals from undergoing septic shock within the established time. Using relevant models to study the inflammatory activity of LPS, we found that all PSs used in this work decreased LPS-induced inflammation, with a more striking effect observed for NMB and curcumin. These data advance the understanding of the mechanisms of LPS inhibition by PSs.

Chlorogenic Acid Potentiates the Anti-Inflammatory Activity of Curcumin in LPS-Stimulated THP-1 Cells

The anti-inflammatory effects of curcumin are well documented. However, the bioavailability of curcumin is a major barrier to its biological efficacy. Low-dose combination of complimentary bioactives appears to be an attractive strategy for limiting barriers to efficacy of bioactive compounds. In this study, the anti-inflammatory potential of curcumin in combination with chlorogenic acid (CGA), was investigated using human THP-1 macrophages stimulated with lipopolysaccharide (LPS). Curcumin alone suppressed TNF-α production in a dose-dependent manner with a decrease in cell viability at higher doses. Although treatment with CGA alone had no effect on TNF-α production, it however enhanced cell viability and co-administration with curcumin at a 1:1 ratio caused a synergistic reduction in TNF-α production with no impact on cell viability. Furthermore, an qRT-PCR analysis of NF-κB pathway components and inflammatory biomarkers indicated that CGA alone was not effective in reducing the mRNA expression of any of the tested inflammatory marker genes, except TLR-4. However, co-administration of CGA with curcumin, potentiated the anti-inflammatory effects of curcumin. Curcumin and CGA together reduced the mRNA expression of pro-inflammatory cytokines [TNF-α (~88%) and IL-6 (~99%)], and COX-2 (~92%), possibly by suppression of NF-κB (~78%), IκB-β-kinase (~60%) and TLR-4 receptor (~72%) at the mRNA level. Overall, co-administration with CGA improved the inflammation-lowering effects of curcumin in THP-1 cells.

Curcumin-laden exosomes target ischemic brain tissue and alleviate cerebral ischemia-reperfusion injury by inhibiting ROS-mediated mitochondrial apoptosis

The pathogenesis of ischemic cerebrovascular disease has revealed that ischemia-reperfusion (I/R) injury often leads to aggravation of metabolic oxidative stress and blood-brain barrier (BBB) destruction, eventually causing secondary brain tissue damage. Accumulated reactive oxygen species (ROS) in focal ischemia activate mitochondria-mediated apoptosis and damage the BBB by degrading tight junction proteins (TJPs). Herein, we report macrophage-derived exosomes (Ex) loaded with curcumin (cur) as a multifunctional biomimetic delivery vehicle (Ex-cur) for targeting ischemic brain tissue and alleviating cerebral I/R injury by inhibiting ROS-mediated mitochondrial apoptosis in a transient cerebral ischemia rat model. The design principle relies on unique features of macrophage-derived exosomes and the natural ingredient cur. Specifically, cur can be entrapped within exosomes when incubated with murine macrophage RAW264.7 cells, and its stability is subsequently significantly improved. The resultant Ex-cur can target ischemic regions by leveraging the targeting migration capability of Ex driven by inflammation. Accumulated Ex-cur in ischemic regions is experimentally proven to be highly effective at reducing ROS accumulation by virtue of the antioxidant properties of cur. Using Ex-cur to down-regulate ROS accumulation in lesions, we alleviate BBB damage and suppress mitochondria-mediated neuronal apoptosis, which is confirmed by a series of relevant protein analysis. These findings demonstrate good therapeutic efficacy of Ex-cur for treating I/R injury, providing experimental evidence for the potential clinical benefits of Ex-cur for other modes of neuroprotection.

Role of the neurovascular unit in the process of cerebral ischemic injury

Cerebral ischemic injury exhibits both high morbidity and mortality worldwide. Traditional research of the pathogenesis of cerebral ischemic injury has focused on separate analyses of the involved cell types. In recent years, the neurovascular unit (NVU) mechanism of cerebral ischemic injury has been proposed in modern medicine. Hence, more effective strategies for the treatment of cerebral ischemic injury may be provided through comprehensive analysis of brain cells and the extracellular matrix. However, recent studies that have investigated the function of the NVU in cerebral ischemic injury have been insufficient. In addition, the metabolism and energy conversion of the NVU depend on interactions among multiple cell types, which make it difficult to identify the unique contribution of each cell type. Therefore, in the present review, we comprehensively summarize the regulatory effects and recovery mechanisms of four major cell types (i.e., astrocytes, microglia, brain-microvascular endothelial cells, and neurons) in the NVU under cerebral ischemic injury, as well as discuss the interactions among these cell types in the NVU. Furthermore, we discuss the common signaling pathways and signaling factors that mediate cerebral ischemic injury in the NVU, which may help to provide a theoretical basis for the comprehensive elucidation of cerebral ischemic injury.

Resveratrol reduces cerebral edema through inhibition of de novo SUR1 expression induced after focal ischemia

Cerebral edema is a clinical problem that frequently follows ischemic infarcts. Sulfonylurea receptor 1 (SUR1) is an inducible protein that can form a heteromultimeric complex with aquaporin 4 (AQP4) that mediate the ion/water transport involved in brain tissue swelling. Transcription of the Abcc8 gene coding for SUR1 depends on the activity of transcriptional factor SP1, which is modulated by the cellular redox environment. Since oxidative stress is implicated in the induced neuronal damage in ischemia and edema formation, the present study aimed to evaluate if the antioxidant resveratrol (RSV) prevents the damage by reducing the de novo expression of SUR1 in the ischemic brain. Male Wistar rats were subjected to 2 h of middle cerebral artery occlusion followed by different times of reperfusion. RSV (1.9 mg/kg; i.v.) was administered at the onset of reperfusion. Brain damage and edema formation were recognized by neurological evaluation, time of survival, TTC (2,3,5-Triphenyltetrazolium chloride) staining, Evans blue extravasation, and water content. RSV mechanism of action was studied by SP1 binding activity measured through the Electrophoretic Mobility Shift Assay, and Abcc8 and Aqp4 gene expression evaluated by qPCR, immunofluorescence, and Western blot. We found that RSV reduced the infarct area and cerebral edema, prevented blood-brain barrier damage, improved neurological performance, and increased survival. Additionally, our findings suggest that the antioxidant activity of RSV targeted SP transcription factors and inhibited SUR1 and AQP4 expression. Thus, RSV by decreasing SUR1 expression could contribute to reducing edema formation, constituting a therapeutic alternative for edema reduction in stroke.

Targeting Oxidative Stress and Inflammation to Prevent Ischemia-Reperfusion Injury

The cerebral ischemia injury can result in neuronal death and/or functional impairment, which leads to further damage and dysfunction after recovery of blood supply. Cerebral ischemia/reperfusion injury (CIRI) often causes irreversible brain damage and neuronal injury and death, which involves many complex pathological processes including oxidative stress, amino acid toxicity, the release of endogenous substances, inflammation and apoptosis. Oxidative stress and inflammation are interactive and play critical roles in ischemia/reperfusion injury in the brain. Oxidative stress is important in the pathological process of ischemic stroke and is critical for the cascade development of ischemic injury. Oxidative stress is caused by reactive oxygen species (ROS) during cerebral ischemia and is more likely to lead to cell death and ultimately brain death after reperfusion. During reperfusion especially, superoxide anion free radicals, hydroxyl free radicals, and nitric oxide (NO) are produced, which can cause lipid peroxidation, inflammation and cell apoptosis. Inflammation alters the balance between pro-inflammatory and anti-inflammatory factors in cerebral ischemic injury. Inflammatory factors can therefore stimulate or exacerbate inflammation and aggravate ischemic injury. Neuroprotective therapies for various stages of the cerebral ischemia cascade response have received widespread attention. At present, neuroprotective drugs mainly include free radical scavengers, anti-inflammatory agents, and anti-apoptotic agents. However, the molecular mechanisms of the interaction between oxidative stress and inflammation, and their interplay with different types of programmed cell death in ischemia/reperfusion injury are unclear. The development of a suitable method for combination therapy has become a hot topic.

Platycarya strobilacea leaf extract protects mice brain with focal cerebral ischemia by antioxidative property

The leaf extract of Platycarya strobilacea (PSL) has long been recognized as possessing various health-promoting activities. However, information on its possible protective effects against ischemic stroke is currently lacking. Here, using a mouse model of focal cerebral ischemia (fCI), we studied the protective potential of an oral supplement of PSL. Mice were randomly divided into four groups: SO, a group subjected to a sham-operation; VEH, pretreated with distilled water and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R); PSL-L and PSL-H, pretreated with low (20 mg/kg) and high (100 mg/kg) doses of PSL, respectively, and subjected to the MCAO/R procedure. PSL was administered via an oral route daily for 8 days prior to surgery. We then measured the infarct volumes and sensorimotor deficits and studied the underlying antioxidant mechanisms by quantifying apoptosis, reactive oxygen species (ROS) generation, oxidative damages, and antioxidant enzymes in the ischemic cortex. The results showed a marked attenuation in infarct volume and sensorimotor deficits in both the PSL-L and PSL-H groups when compared with VEH. The terminal deoxynucleotidyl transferase dUTP nick end labeling and the immunohistochemical detection of the cleaved caspase-3 revealed that PSL could reduce cellular apoptosis in the ischemic lesion in a dose-dependent manner. The dihydroethidium-fluorescence, 4-hydroxynonenal, and 8-hydroxyl-2'-deoxyguanosine immunoreactivities in the ischemic lesion were markedly attenuated in the PSL-L group compared with the VEH group, indicating that PSL could attenuate ROS generation and the associated oxidative damage in the ischemic cortex. Finally, western blot results indicated that PSL can upregulate levels of heme oxygenase-1 (HO-1), an antioxidant enzyme, in the lesion area. Together, these results suggest that PSL can exert protective effects against fCI, and the mechanism may involve HO-1 upregulation.

Collagen–curcumin nanocomposites showing an enhanced neuroprotective effect against short term focal cerebral ischemia

The effectiveness of curcumin in treating cerebral ischemia has been reported in recent studies. However, its mode of action is still not defined. The objective of the present study is to formulate collagen–curcumin nanocomposites which will work effectively against cerebral ischemia/reperfusion injury. Ischemic injury is followed by inflammatory damage and oxidative stress, which together contribute a lot in the pathogenesis of cerebral ischemia and may be considered a good target for treatment. The present study focused on examining the effectiveness of collagen–curcumin nanocomposites stabilized by increasing the degree of crosslinking in reducing oxidative stress associated with brain injury resulting from cerebral ischemia. The collagen nanoparticles were prepared by conjugating collagen on the surface of Tween©80 micelles, and further stabilizing them using crosslinkers. The effectiveness of the prepared nanocomposite was validated by performing infarct analysis followed by biochemical, behavioral, histopathological and immunohistochemical studies. The outcomes of this study are promising for the use of collagen–curcumin nanocomposites in showing neuroprotective potential in treating ischemic injury.

A synthetic collagen–curcumin nanocomposite enhanced drug efficacy by increasing its bioavailability and showing slow and sustained drug release in the treatment against focal cerebral ischemia.

Research of stroke combined hyperlipidemia-induced erectile dysfunction in rat model

Objective: The study was aimed to evaluate the influences of erectile dysfunction (ED) in a rat model of stroke combined with hyperlipidemia (HLP). Methods: Male Sprague-Dawley rats were divided into control and hyperlipidemia (HLP) groups. HLP model was constructed by feeding with high-fat and cholesterol diets. Serum levels of total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL), triglyceride (TG), and non-HDL were identified to check the model was success. Stroke model was established by FeCl₃. ICP/MAP value was detected to evaluate the erectile function of rats. Serum level of lipoproteins and the expressions of endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF) were detected by ELISA. Hematoxylin-eosin (HE) staining of corpus cavernosum and measurement of penis length were utilized to assessment erectile function. Western blot was used. Results: TC, TG, LDL, and non-HDL-C in serum were up-regulated, while HDL level was attenuated. After treatment, the serum lipid level recovered. From the ICP/MAP values, the erectile function of both two treatment groups recovered. The expression of PDE5A was up-regulated, while the levels of eNOS and cGMP were suppressed after surgery. The length of penis was decreased, and corpus cavernosum was damaged following HLP and stroke. However, the erectile function was recovered after treatment. Conclusion: Stroke combined HLP caused ED through NO-cGMP-PDE5 pathway.

Brain targeting of Baicalin and Salvianolic acid B combination by OX26 functionalized nanostructured lipid carriers

In order to deliver Salvianolic acid B (Sal B) and Baicalin (BA) to the brain tissue to repair neuron damage and improve cerebral ischemia-reperfusion injury (IRI), in our previous study, a nanostructured lipid carrier (NLC) containing BA and Sal B, and modified by the transferrin receptor monoclonal antibody OX26 (OX26-BA/Sal B-NLC) was constructed. The present study is to evaluate its in vitro release behavior, in vitro and in vivo targeting ability, in vitro pharmacodynamics and brain pharmacokinetics. The results showed that the release mechanism of the formulation was in line with the Weibull model release equation. The in-vitro and in-vivo targeting ability study exhibited that OX26 modified formulations was obviously higher than that of non-modified and solution groups. The results of in vitro preliminary study to investigate the protective effect of OX26-BA/Sal B-NLC on oxygen-glucose deprivation/reperfusion injured cells showed that it could decrease the injury. Furthermore, the results of brain microdialysis study showed that the OX26-modified preparation group could significantly increase the content of BA in the brain. In the solution group and the unmodified group, Sal B can only be detected at few time points, while OX26-modified BA/Sal B-NLC could be detected within 4 h. These results indicating that OX26-modified NLC can promote the brain delivery of Sal B and BA combination.

Curcumin inhibits LPS-induced neuroinflammation by promoting microglial M2 polarization via TREM2/ TLR4/ NF-κB pathways in BV2 cells

Microglia mediate multiple facets of neuroinflammation, which plays a double-edged role in various brain diseases via distinct microglial phenotypes (deleterious M1 and neuroprotective M2). Therefore, the inhibition of overactivated inflammatory M1 microglia by switching to the protective M2 phenotype appears to be a potential therapeutic strategy in neuroinflammatory disorders. Curcumin has been shown to exhibit anti-inflammatory and neuroprotective activities. The present study investigated the potential effects of curcumin on microglial M1/M2 polarization and elucidated the possible molecular mechanisms of action in vitro. In this study, the BV2 microglial cell line was pretreated with different curcumin concentrations in the presence or absence of lipopolysaccharide (LPS) to assess the anti-inflammatory efficacy of curcumin based on the morphological and inflammatory changes. The cytotoxicity of curcumin for BV2 cells was evaluated using the CCK-8 assay. Further, the effect of curcumin concentrations on LPS-induced BV2 cells was studied. The morphological changes were observed using an optical microscope and immunofluorescent staining. Nitric oxide (NO) expression was determined using the Griess reagent. The expression of cytokines and inflammatory mediators was also measured by ELISA, qRT-PCR, flow cytometry, and immunofluorescence. Western blot analysis was used to determine the levels of triggering receptor expressed on myeloid cells 2 (TREM2), toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB) p65, p-NF-κB p65, IκB, and p-IκB expression. Results showed that curcumin concentrations less than 10 μM did not induce any detectable cytotoxicity but decreased BV2 cell viability up to 20 μM. Curcumin inhibited LPS-induced microglial activation. Curcumin treatment switched the M1 pro-inflammatory phenotype to the M2 anti-inflammatory phenotype by decreasing the expression of M1 markers (i.e., iNOS, IL-1β, IL-6, and CD16/32) and elevating the expression of M2 markers (i.e., arginase 1, IL-4, IL-10, and CD206). Interestingly, curcumin attenuated the activation of TLR4/NF-κB pathways and the downregulation of TREM2 expression in LPS-activated BV2 cells. Collectively, these results suggest that curcumin significantly alleviates LPS-induced inflammation by regulating microglial (M1/M2) polarization by reducing the imbalance of TREM2 and TLR4 and balancing the downstream NF-κB activation.

The Medical Management of Cerebral Edema: Past, Present, and Future Therapies

Cerebral edema is commonly associated with cerebral pathology, and the clinical manifestation is largely related to the underlying lesioned tissue. Brain edema usually amplifies the dysfunction of the lesioned tissue and the burden of cerebral edema correlates with increased morbidity and mortality across diseases. Our modern-day approach to the medical management of cerebral edema has largely revolved around, an increasingly artificial distinction between cytotoxic and vasogenic cerebral edema. These nontargeted interventions such as hyperosmolar agents and sedation have been the mainstay in clinical practice and offer noneloquent solutions to a dire problem. Our current understanding of the underlying molecular mechanisms driving cerebral edema is becoming much more advanced, with differences being identified across diseases and populations. As our understanding of the underlying molecular mechanisms in neuronal injury continues to expand, so too is the list of targeted therapies in the pipeline. Here we present a brief review of the molecular mechanisms driving cerebral edema and a current overview of our understanding of the molecular targets being investigated.