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

Anti-apoptosis effect of traditional Chinese medicine in the treatment of cerebral ischemia-reperfusion injury

Cerebral ischemia, one of the leading causes of neurological dysfunction of brain cells, muscle dysfunction, and death, brings great harm and challenges to individual health, families, and society. Blood flow disruption causes decreased glucose and oxygen, insufficient to maintain normal brain tissue metabolism, resulting in intracellular calcium overload, oxidative stress, neurotoxicity of excitatory amino acids, and inflammation, ultimately leading to neuronal cell necrosis, apoptosis, or neurological abnormalities. This paper summarizes the specific mechanism of cell injury that apoptosis triggered by reperfusion after cerebral ischemia, the related proteins involved in apoptosis, and the experimental progress of herbal medicine treatment through searching, analyzing, and summarizing the PubMed and Web Of Science databases, which includes active ingredients of herbal medicine, prescriptions, Chinese patent medicines, and herbal extracts, providing a new target or new strategy for drug treatment, and providing a reference for future experimental directions and using them to develop suitable small molecule drugs for clinical application. With the research of anti-apoptosis as the core, it is important to find highly effective, low toxicity, safe and cheap compounds from natural plants and animals with abundant resources to prevent and treat Cerebral ischemia/reperfusion (I/R) injury (CIR) and solve human suffering. In addition, understanding and summarizing the apoptotic mechanism of cerebral ischemia-reperfusion injury, the microscopic mechanism of CIR treatment, and the cellular pathways involved will help to develop new drugs.

Ro25-6981 alleviates neuronal damage and improves cognitive deficits by attenuating oxidative stress via the Nrf2/ARE pathway in ischemia/reperfusion rats

OBJECTIVES

Oxidative stress plays a crucial role in the initiation and progression of cerebral ischemia‒reperfusion injury (CIRI). Therefore, ameliorating oxidative damage is considered to be a beneficial strategy for the treatment of CIRI. NMDAR NR2B subunit antagonists have been reported to be beneficial for synaptic plasticity, neuropathic pain, epilepsy, and cerebral ischemia. However, it remains unclear whether the NR2B subunit antagonist Ro25-6981 has any effect on CIRI.

METHODS

In this study, the Morris water maze test and passive avoidance test were used to detect spatial learning and memory. Neuronal loss was measured by Nissl staining. The expression of NSE was assayed by immunohistochemistry. The activities of MDA, 8-OHdG, SOD, GSH-Px, GST and CAT were detected by assay kits. Real-time PCR was used to detect the mRNA levels of hippocampal SOD, GSH-Px and HO-1. Western blotting was used to measure the activation of the Nrf2/ARE pathway by Ro25-6981.

RESULTS

Ro25-6981 ameliorated cognitive deficits and neuronal damage induced by ischemia‒reperfusion (I/R). Neuronal injury was decreased and the expression of NSE was increased in the CA1 regions of the hippocampus of I/R rats after Ro25-6981 treatment. Moreover, Ro25-6981 alleviated the levels of MDA and 8-OHdG by elevating the activities of SOD, GSH-Px, GST and CAT. Meanwhile, the mRNA levels of SOD, GSH-Px and HO-1 were increased in I/R rats after Ro25-6981 treatment. Furthermore, Ro25-6981 promoted the translocation of Nrf2 to the nucleus, promoting the expression of the Nrf2 downstream genes HO-1 and NQO1.

CONCLUSION

The present study indicated that the improvement in the antioxidant properties of Ro25-6981 is mediated by the Nrf2/ARE pathway. This is the first study to demonstrate a favorable effect of Ro25-6981 on cognitive impairment in a CIRI rat model, rendering this NR2B subunit antagonist a promising agent for the treatment or prevention of CIRI.

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.

Exosomes as natural nanocarrier-based drug delivery system: recent insights and future perspectives

Exosomes are nanosized (size ~ 30-150 nm) natural vesicular structures released from cells by physiological processes or pathological circumstances. Exosomes are growing in popularity as a result of their many benefits over conventional nanovehicles, including their ability to escape homing in the liver or metabolic destruction and their lack of undesired accumulation before reaching their intended targets. Various therapeutic molecules, including nucleic acids, have been incorporated into exosomes by different techniques, many of which have shown satisfactory performance in various diseases. Surface-modified exosomes are a potentially effective strategy, and it increases the circulation time and produces the specific drug target vehicle. In this comprehensive review, we describe composition exosomes biogenesis and the role of exosomes in intercellular signaling and cell-cell communications, immune responses, cellular homeostasis, autophagy, and infectious diseases. In addition, we discuss the role of exosomes as diagnostic markers, and their therapeutic and clinical implications. Furthermore, we addressed the challenges and outstanding developments in exosome research and discuss future perspectives. In addition to the current status of exosomes as a therapeutic carrier, the lacuna in the clinical development lifecycles along with the possible strategies to fill the lacuna have been addressed.

Curcumin Ameliorates Age-Induced Tight Junction Impaired in Porcine Sertoli Cells by Inactivating the NLRP3 Inflammasome through the AMPK/SIRT3/SOD2/mtROS Signaling Pathway

Blood-testis barrier (BTB) made of concomitant junction apparatus between Sertoli cells (SCs) is crucial for spermatogenesis. The tight junction (TJ) function is impaired in SCs with age, exhibiting an intimate relationship to testicular dysfunction induced by age. In this study, compared with those in young boars, TJ proteins (i.e., Occludin, ZO-1, and plus Claudin-11) were discovered to have reduced expressions in testes, and spermatogenesis ability declined in old boars. An in vitro age model for D-gal-treated porcine SCs was established, the performance of Curcumin as a natural antioxidant and anti-inflammatory compound in affecting the TJ function of SCs was appraised, and related molecular mechanisms were exploited. The results manifested that 40 g/L D-gal downregulated ZO-1, Claudin-11, and Occludin in terms of the expression in SCs, whereas Curcumin restored such expressions in D-gal-treated SCs. Using the AMPK and SIRT3 inhibiters demonstrated that activation of the AMPK/SIRT3 pathway was associated with Curcumin, which not only rescued the expression of ZO-1, Occludin, Claudin-11, and SOD2 but also inhibited the production of mtROS and ROS and the activation of NLRP3 inflammasome and release of IL-1β in D-gal-treated SCs. Furthermore, with mtROS scavenger (mito-TEMPO), NLRP3 inhibitor (MCC950) plus IL-1Ra treatment ameliorated D-gal-caused TJ protein decline in SCs. In vivo data also showed that Curcumin alleviated TJ impairment in murine testes, improved D-gal-triggered spermatogenesis ability, and inactivated the NLRP3 inflammasome by virtue of the AMPK/SIRT3/mtROS/SOD2 signal transduction pathway. Given the above findings, a novel mechanism where Curcumin modulates BTB function to improve spermatogenesis ability in age-related male reproductive disorder is characterized.

cPKCγ Inhibits Caspase-9-Initiated Neuronal Apoptosis in an Ischemia Reperfusion Model In Vitro Through p38 MAPK-p90RSK-Bad Pathway

Strokes are one of the leading causes of death and disability in the world. Previously we have found that conventional protein kinase Cγ (cPKCγ) plays neuroprotective role in ischemic strokes. Further, we found that cPKCγ knockdown increased the level of cleaved (cl)-Caspase-3. However, the precise mechanisms underlying cPKCγ-mediated neuronal death remain unclear. To this end, a model incorporating 1 h oxygen-glucose deprivation/24 h reoxygenation (1 h OGD/24 h R) was established in cortical neurons. We found that cPKCγ knockdown remarkably increased neuronal death after OGD. We also found that cPKCγ knockdown increased the level of cl-Caspase-3 through the upstream initiators Capsases-9 (not Caspase-8/12) in OGD-treated neurons. Overexpression of cPKCγ could decrease neuronal death and cl-Caspase-3 and -9 levels. Moreover, cPKCγ knockdown further reduced the phosphorylation levels of p38 MAPK, p90RSK, and Bad. In addition, the protein levels of Bcl-2 and Bcl-xl were decreased after cPKCγ knockdown, whereas that of Bax was increased. In conclusion, our results suggest that cPKCγ partly alleviates ischemic injury through activating the p38 MAPK-p90RSK-Bad pathway and inhibiting Caspase-9 initiated apoptosis. This may have potential as a therapeutic target for ischemic stroke.

Celastrol targeting Nedd4 reduces Nrf2-mediated oxidative stress in astrocytes after ischemic stroke

Stroke is the second leading cause of death worldwide, and oxidative stress plays a crucial role. Celastrol exhibits strong antioxidant properties in several diseases; however, whether it can affect oxidation in cerebral ischemic-reperfusion injury (CIRI) remains unclear. This study aimed to determine whether celastrol could reduce oxidative damage during CIRI and to elucidate the underlying mechanisms. Here, we found that celastrol attenuated oxidative injury in CIRI by upregulating nuclear factor E2-related factor 2 (Nrf2). Using alkynyl-tagged celastrol and liquid chromatography-tandem mass spectrometry, we showed that celastrol directly bound to neuronally expressed developmentally downregulated 4 (Nedd4) and then released Nrf2 from Nedd4 in astrocytes. Nedd4 promoted the degradation of Nrf2 through K48-linked ubiquitination and thus contributed to astrocytic reactive oxygen species production in CIRI, which was significantly blocked by celastrol. Furthermore, by inhibiting oxidative stress and astrocyte activation, celastrol effectively rescued neurons from axon damage and apoptosis. Our study uncovered Nedd4 as a direct target of celastrol, and that celastrol exerts an antioxidative effect on astrocytes by inhibiting the interaction between Nedd4 and Nrf2 and reducing Nrf2 degradation in CIRI.

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.

Poly(pro-curcumin) Materials Exhibit Dual Release Rates and Prolonged Antioxidant Activity as Thin Films and Self-Assembled Particles

Curcumin is a natural polyphenol that exhibits remarkable antioxidant and anti-inflammatory activities; however, its clinical application is limited in part by its physiological instability. Here, we report the synthesis of curcumin-derived polyesters that release curcumin upon hydrolytic degradation to improve curcumin stability and solubility in physiological conditions. Curcumin was incorporated in the polymer backbone by a one-pot condensation polymerization in the presence of sebacoyl chloride and polyethylene glycol (PEG, M_n = 1 kDa). The thermal and mechanical properties, surface wettability, self-assembly behavior, and drug-release kinetics all depend sensitively on the mole percentage of curcumin incorporated in these statistical copolymers. Curcumin release was triggered by the hydrolysis of phenolic esters on the polymer backbone, which was confirmed using a PEGylated curcumin model compound, which represented a putative repeating unit within the polymer. The release rate of curcumin was controlled by the hydrophilicity of the polymers. Burst release (2 days) and extended release (>8 weeks) can be achieved from the same polymer depending on curcumin content in the copolymer. The materials can quench free radicals for at least 8 weeks and protect primary neurons from oxidative stress in vitro. Further, these copolymer materials could be processed into both thin films and self-assembled particles, depending on the solvent-based casting conditions. Finally, we envision that these materials may have potential for neural tissue engineering application, where antioxidant release can mitigate oxidative stress and the inflammatory response following neural injury.

Analysis of the Research Hotspot of Exosomes in Cardiovascular Disease: A Bibliometric-based Literature Review

OBJECTIVE

To investigate the current status and development trend of research on exosomes in cardiovascular disease (CVD) using bibliometric analysis and to elucidate trending research topics.

METHODS

Research articles on exosomes in CVD published up to April 2022 were retrieved from the Web of Science database. Data were organized using Microsoft Office Excel 2019. CiteSpace 6.1 and VOSviewer 1.6.18 were used for bibliometric analysis and result visualization.

RESULTS

Overall, 256 original research publications containing 190 fundamental research publications and 66 clinical research publications were included. "Extracellular vesicle" was the most frequent research keyword, followed by "microrna," "apoptosis," and "angiogenesis." Most publications were from China (187, 73.05%), followed by the United States (57, 22.27%), the United Kingdom (7, 2.73%), and Japan (7, 2.73%). A systematic review of the publications revealed that myocardial infarction and stroke were the most popular topics and that exosomes and their contents, such as microRNAs (miRNAs), play positive roles in neuroprotection, inhibition of autophagy and apoptosis, promotion of angiogenesis, and protection of cardiomyocytes.

CONCLUSION

Research on exosomes in CVD has attracted considerable attention, with China having the most published studies. Fundamental research has focused on CVD pathogenesis; exosomes regulate the progression of CVD through biological processes, such as the inflammatory response, autophagy, and apoptosis. Clinical research has focused on biomarkers for CVD; studies on using miRNAs in exosomes as disease markers for diagnosis could become a future trend.

Hybrid exosomes, exosome-like nanovesicles and engineered exosomes for therapeutic applications

Exosomes are endosome-derived nanovesicles involved in cellular communication. They are natural nanocarriers secreted by various cells, making them suitable candidates for diverse drug delivery and therapeutic applications from a material standpoint. They have a phospholipid bilayer decorated with functional molecules and an enclosed parental matrix, which has attracted interest in developing designer/hybrid engineered exosome nanocarriers. The structural versatility of exosomes allows the modification of their original configuration using various methods, including genetic engineering, chemical procedures, physical techniques, and microfluidic technology, to load exosomes with additional cargo for expanded biomedical applications. Exosomes show enormous potential for overcoming the limitations of conventional nanoparticle-based techniques in targeted therapy. This review highlights the exosome sources, characteristics, state of the art in the field of hybrid exosomes, exosome-like nanovesicles and engineered exosomes as potential cargo delivery vehicles for therapeutic applications.

Neuroprotective Strategies for Stroke by Natural Products: Advances and Perspectives

Cerebral ischemic stroke is a disease with high prevalence and incidence. Its management focuses on rapid reperfusion with intravenous thrombolysis and endovascular thrombectomy. Both therapeutic strategies reduce disability, but the therapy time window is short, and the risk of bleeding is high. Natural products (NPs) have played a key role in drug discovery, especially for cancer and infectious diseases. However, they have made little progress in clinical translation and pose challenges to the treatment of stroke. Recently, with the investigation of precise mechanisms in cerebral ischemic stroke and the technological development of NP-based drug discovery, NPs are addressing these challenges and opening up new opportunities in cerebral stroke. Thus, in this review, we first summarize the structure and function of diverse NPs, including flavonoids, phenols, terpenes, lactones, quinones, alkaloids, and glycosides. Then we propose the comprehensive neuroprotective mechanism of NPs in cerebral ischemic stroke, which involves complex cascade processes of oxidative stress, mitochondrial damage, apoptosis or ferroptosis-related cell death, inflammatory response, and disruption of the blood-brain barrier (BBB). Overall, we stress the neuroprotective effect of NPs and their mechanism on cerebral ischemic stroke for a better understanding of the advances and perspective in NPs application that may provide a rationale for the development of innovative therapeutic regimens in ischemic stroke.

Therapeutic potential of exosome-based personalized delivery platform in chronic inflammatory diseases

In the inflammatory microenvironment, there are numerous exosomes secreted by immune cells (Macrophages, neutrophils, dendritic cells), mesenchymal stem cells (MSCs) and platelets as intercellular communicators, which participate in the regulation of inflammation by modulating gene expression and releasing anti-inflammatory factors. Due to their good biocompatibility, accurate targeting, low toxicity and immunogenicity, these exosomes are able to selectively deliver therapeutic drugs to the site of inflammation through interactions between their surface-antibody or modified ligand with cell surface receptors. Therefore, the role of exosome-based biomimetic delivery strategies in inflammatory diseases has attracted increasing attention. Here we review current knowledge and techniques for exosome identification, isolation, modification and drug loading. More importantly, we highlight progress in using exosomes to treat chronic inflammatory diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), atherosclerosis (AS), and inflammatory bowel disease (IBD). Finally, we also discuss their potential and challenges as anti-inflammatory drug carriers.

Exosomes in pathogenesis, diagnosis, and therapy of ischemic stroke

Ischemic stroke is one of the major contributors to death and disability worldwide. Thus, there is an urgent need to develop early brain tissue perfusion therapies following acute stroke and to enhance functional recovery in stroke survivors. The morbidity, therapy, and recovery processes are highly orchestrated interactions involving the brain with other tissues. Exosomes are natural and ideal mediators of intercellular information transfer and recognized as biomarkers for disease diagnosis and prognosis. Changes in exosome contents express throughout the physiological process. Accumulating evidence demonstrates the use of exosomes in exploring unknown cellular and molecular mechanisms of intercellular communication and organ homeostasis and indicates their potential role in ischemic stroke. Inspired by the unique properties of exosomes, this review focuses on the communication, diagnosis, and therapeutic role of various derived exosomes, and their development and challenges for the treatment of cerebral ischemic stroke.

Exosomes in Cerebral Ischemia-Reperfusion Injury: Current Perspectives and Future Challenges

Cerebral ischemia impedes the functional or metabolic demands of the central nervous system (CNS), which subsequently leads to irreversible brain damage. While recanalization of blocked vessels recovers cerebral blood flow, it can also aggravate brain injury, termed as ischemia/reperfusion (I/R) injury. Exosomes, nanometric membrane vesicles, attracted wide attention as carriers of biological macromolecules. In the brain, exosomes can be secreted by almost all types of cells, and their contents can be altered during the pathological and clinical processes of cerebral I/R injury. Herein, we will review the current literature on the possible role of cargos derived from exosomes and exosomes-mediated intercellular communication in cerebral I/R injury. The PubMed and Web of Science databases were searched through January 2015. The studies published in English were identified using search terms including "exosomes", "cerebral ischemia-reperfusion injury", "brain ischemia-reperfusion injury", and "stroke". We will also focus on the potential therapeutic effects of stem cell-derived exosomes and underlying mechanisms in cerebral I/R injury. Meanwhile, with the advantages of low immunogenicity and cytotoxicity, high bioavailability, and the capacity to pass through the blood-brain barrier, exosomes also attract more attention as therapeutic modalities for the treatment of cerebral I/R injury.

Curcumin-Primed Umbilical Cord Mesenchymal Stem Cells-Derived Extracellular Vesicles Improve Motor Functional Recovery of Mice with Complete Spinal Cord Injury by Reducing Inflammation and Enhancing Axonal Regeneration

Background Transplantation of extracellular vesicles (EVs) from stem cells is a feasible scheme for traumatic spinal cord injury (SCI). However, there is no relevant report about stem cells derived EVs loaded with curcumin for SCI treatment. Methods Mouse umbilical cord mesenchymal stem cells (MUMSCs) were incubated in the medium containing curcumin (20 µM) for 48 h. Extracellular vesicles (EVs) and curcumin-primed EVs (Cur-EVs) were collected by ultracentrifugation. Characterizations of EVs/Cur-EVs were analyzed by western blotting with CD9 and CD81 antibodies, transmission electron microscopy and nano-tracking analysis. Curcumin in the Cur-EVs was analyzed by high performance liquid phase chromatography at 430 nm wavelength. Immunofluorescence and in vivo imaging methods were used to confirm biocompatibility of EVs/Cur-EVs in vitro and in vivo. Mice with complete SCI were treated with EVs/Cur-EVs to compare the differences of locomotor function, inflammation, histological changes and remyelination. Results The isolated EVs and Cur-EVs from MUMSCs have good biocompatibility. Compared with the model mice, the locomotor function, inflammation and axonal regeneration of mice were significantly improved after injection of Cur-EVs/EVs. Furthermore, it is more effective for structural and functional recovery of complete SCI after the Cur-EVs treatment compared with the EVs treatment. In the lesioned regions, the macrophage polarization from M1 to M2 phenotype and axonal regeneration were significantly improved in the Cur-EVs group compared with the EVs group. Conclusions Our data suggested that EVs from MUMSCs might be a promising drug delivery vehicle of curcumin for the efficient and biocompatible treatment of severe SCI.

Effects and Mechanisms of Exosomes from Different Sources in Cerebral Ischemia

Cerebral ischemia refers to the symptom of insufficient blood supply to the brain. Cells of many different origins participate in the process of repairing damage after cerebral ischemia occurs, in which exosomes secreted by the cells play important roles. For their characteristics, such as small molecular weight, low immunogenicity, and the easy penetration of the blood-brain barrier (BBB), exosomes can mediate cell-to-cell communication under pathophysiological conditions. In cerebral ischemia, exosomes can reduce neuronal damage and improve the brain microenvironment by regulating inflammation, mediating pyroptosis, promoting axonal growth, and stimulating vascular remodeling. Therefore, exosomes have an excellent application prospect for the treatment of cerebral ischemia. This article reviews the roles and mechanisms of exosomes from different sources in cerebral ischemia and provides new ideas for the prevention and treatment of cerebral ischemia.

The crosstalk among autophagy, apoptosis, and pyroptosis in cardiovascular disease

In recent years, the mechanism of cell death has become a hotspot in research on the pathogenesis and treatment of cardiovascular disease (CVD). Different cell death modes, including autophagy, apoptosis, and pyroptosis, are mosaic with each other and collaboratively regulate the process of CVD. This review summarizes the interaction and crosstalk of key pathways or proteins which play a critical role in the entire process of CVD and explores the specific mechanisms. Furthermore, this paper assesses the interrelationships among these three cell deaths and reviews how they regulate the pathogenesis of CVD. By understanding how these three cell death modes go together we can learn about the pathogenesis of CVD, which will enable us to identify new targets for preventing, controlling, and treating CVD. It will not only reduce mortality but also improve the quality of life.

Exosomes as CNS Drug Delivery Tools and Their Applications

Central nervous system (CNS) diseases threaten the health of people all over the world. However, due to the structural and functional particularities of the brain and spinal cord, CNS-targeted drug development is rather challenging. Exosomes are small cellular vesicles with lipid bilayers that can be secreted by almost all cells and play important roles in intercellular communication. The advantages of low immunogenicity, the ability to cross the blood-brain barrier, and the flexibility of drug encapsulation make them stand out among CNS drug delivery tools. Herein, we reviewed the research on exosomes in CNS drug delivery over the past decade and outlined the impact of the drug loading mode, administration route, and engineered modification on CNS targeting. Finally, we highlighted the problems and prospects of exosomes as CNS drug delivery tools.

Simvastatin encapsulated in exosomes can enhance its inhibition of relapse after orthodontic tooth movement

INTRODUCTION

Relapse after orthodontic treatment is a major clinical issue in the dental field. Studies indicate that simvastatin may, to some extent, decrease the rate and magnitude of relapse status. Recent evidence demonstrated that exosome-based drug delivery has a broad prospect of clinical application. Hence, this study investigates whether simvastatin encapsulated in exosomes can inhibit relapse after orthodontic tooth movement (OTM).

METHODS

Periodontal ligament stem cells (PDLSCs) and their exosomes (PDLSCs-Exo) were isolated and identified. Exosomal simvastatin was obtained by co-incubation of simvastatin and PDLSCs-Exo. An OTM rat model was established. During the relapse period, rats' local alveolar bone was injected with simvastatin, PDLSCs-Exo, and exosomal simvastatin to examine the effect on relapse. Finally, we analyzed the influence of exosomal simvastatin on osteogenesis at the molecular and histologic levels.

RESULTS

PDLSCs and PDLSCs-Exo were successfully extracted and characterized by multiple means. Simvastatin encapsulated in exosomes can increase the solubility of the drug. Exosomal simvastatin can enhance its inhibition of relapse after OTM in the rat model. The expression level of osteogenic-related genes and proteins in the exosomal simvastatin group is higher than in other groups. Histologic analysis showed a reduction of bone-resorptive lacunae in the exosomal simvastatin group.

CONCLUSIONS

Encapsulating simvastatin into the exosomes derived from PDLSCs can improve simvastatin solubility and enhance the inhibition effect of relapse in the rat model of OTM. Notably, local injection of PDLSCs-Exo alone can also block the relapse after OTM.

Neuroprotective Effect and Possible Mechanisms of Ginsenoside-Rd for Cerebral Ischemia/Reperfusion Damage in Experimental Animal: A Meta-Analysis and Systematic Review

Ischemic stroke, the most common type of stroke, can lead to a long-term disability with the limitation of effective therapeutic approaches. Ginsenoside-Rd (G-Rd) has been found as a neuroprotective agent. In order to investigate and discuss the neuroprotective function and underlying mechanism of G-Rd in experimental animal models following cerebral ischemic/reperfusion (I/R) injury, PubMed, Embase, SinoMed, and China National Knowledge Infrastructure were searched from their inception dates to May 2022, with no language restriction. Studies that G-Rd was used to treat cerebral I/R damage in vivo were selected. A total of 18 articles were included in this paper, and it was showed that after cerebral I/R damage, G-Rd administration could significantly attenuate infarct volume (19 studies, SMD = −1.75 [−2.21 to − 1.30], P < 0.00001). Subgroup analysis concluded that G-Rd at the moderate doses of >10- <50 mg/kg reduced the infarct volume to the greatest extent, and increasing the dose beyond 50 mg/kg did not produce better results. The neuroprotective effect of G-Rd was not affected by other factors, such as the animal species, the order of administration, and the ischemia time. In comparison with the control group, G-Rd administration could improve neurological recovery (lower score means better recovery: 14 studies, SMD = −1.50 [−2.00 to − 1.00], P < 0.00001; higher score means better recovery: 8 studies, SMD = 1.57 [0.93 to 2.21], P < 0.00001). In addition, this review suggested that G-Rd in vivo can antagonize the reduced oxidative stress, regulate Ca²⁺, and inhibit inflammatory, resistance to apoptosis, and antipyroptosis on cerebral I/R damage. Collectively, G-Rd is a promising natural neuroprotective agent on cerebral I/R injury with unique advantages and a clear mechanism of action. More clinical randomized, blind-controlled trials are also needed to confirm the neuroprotective effect of G-Rd on cerebral I/R injury.

Curcumin-Pretreated Adipose-Derived Stem Cells Enhance the Neuroprotective Ability to Repair Rheumatoid Arthritis-Induced Damage in the Rat Brain

Neurodegenerative diseases have become increasingly prevalent in the aged population. Rheumatoid arthritis (RA) is an autoimmune disease that causes systemic inflammation, damaging the neurons. However, only a few treatment options can reduce RA-induced neurodegeneration. This study aimed to evaluate whether adipose-derived stem cells (ADSCs) pretreated with curcumin could ameliorate RA-induced neurodegenerative illness in an RA rat model. Wistar rats were randomly classified into the following four groups: control, RA, RA + ADSC (1 × 10⁶ cells per rat), and RA + curcumin-pretreated ADSC (1 × 10⁶ cells per rat). After treatment for two months, the effects were specifically evaluated in the brains collected from the rats. Our results demonstrated that the transplantation of curcumin-pretreated ADSCs substantially reduced inflammation and apoptosis in the cortices of RA rats compared to those of other groups. Thus, the combination of ADSCs and curcumin exerts a synergistic effect in enhancing neuronal protection in RA rats. In the future, this combination therapeutic strategy can potentially be used as a novel treatment method to reduce RA-induced neurodegenerative disorders.

Bioengineering exosomes for treatment of organ ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a leading cause of death worldwide. It arises from blood reflowing after tissue hypoxia induced by ischemia that causes severe damages due to the accumulation of reactive oxygen species and the activation of inflammatory responses. Exosomes are the smallest members of the extracellular vesicles' family, which originate from nearly all eukaryotic cells. Exosomes have a great potential in the treatment of I/R injury either in native or modified forms. Native exosomes are secreted by different cell types, such as stem cells, and contain components such as specific miRNA molecules with tissue protective properties. On the other hand, exosome bioengineering has recently received increased attention in context of current advances in the purification, manipulation, biological characterization, and pharmacological applications. There are various pre-isolation and post-isolation manipulation approaches that can be utilized to increase the circulation half-life of exosomes or the availability of their bioactive cargos in the target site. In this review, the various therapeutic actions of native exosomes in different I/R injury will be discussed first. Exosome bioengineering approaches will then be explained, including pre- and post-isolation manipulation methods, applicability for delivery of bioactive agents to injured tissue, clinical translation issues, and future perspectives.

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.

Engineering of MSC-Derived Exosomes: A Promising Cell-Free Therapy for Osteoarthritis

Osteoarthritis (OA) is characterized by progressive cartilage degeneration with increasing prevalence and unsatisfactory treatment efficacy. Exosomes derived from mesenchymal stem cells play an important role in alleviating OA by promoting cartilage regeneration, inhibiting synovial inflammation and mediating subchondral bone remodeling without the risk of immune rejection and tumorigenesis. However, low yield, weak activity, inefficient targeting ability and unpredictable side effects of natural exosomes have limited their clinical application. At present, various approaches have been applied in exosome engineering to regulate their production and function, such as pretreatment of parental cells, drug loading, genetic engineering and surface modification. Biomaterials have also been proved to facilitate efficient delivery of exosomes and enhance treatment effectiveness. Here, we summarize the current understanding of the biogenesis, isolation and characterization of natural exosomes, and focus on the large-scale production and preparation of engineered exosomes, as well as their therapeutic potential in OA, thus providing novel insights into exploring advanced MSC-derived exosome-based cell-free therapy for the treatment of OA.

A biomimetic zeolite-based nanoenzyme contributes to neuroprotection in the neurovascular unit after ischaemic stroke via efficient removal of zinc and ROS

Zeolite-based nanomaterials have a large number of applications in the field of medicine due to their high porosity, biocompatibility and biological stability. In this study, we designed cerium (Ce)-doped Linde Type A (LTA) zeolite-based nanomaterials (Ce/Zeo-NMs) as a multifunctional mesoporous nanoenzyme to reduce dysfunction of the neurovascular unit (NVU) and attenuate cerebral ischaemia-reperfusion (I/R) injury. Owing to its unique adsorption capacity and mimetic catalytic activities, Ce@Zeo-NMs adsorbed excess zinc ions and exhibited scavenging activity against reactive oxygen species (ROS) induced by acute I/R, thus reshaping the oxidative and zinc microenvironment in the ischaemic brain. In vivo results demonstrated that Ce@Zeo-NMs significantly reduced ischaemic damage to the NVU by decreasing the infarct area, protecting against breakdown of the blood-brain barrier (BBB) via inhibiting the degradation of tight junction proteins (TJPs) and inhibiting activation of microglia and astrocytes in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). Taken together, these findings indicated that Ce@Zeo-NMs may serve as a promising dual-targeting therapeutic agent for alleviating cerebral I/R injury. STATEMENT OF SIGNIFICANCE: Cerium (Ce)-doped Linde Type A zeolite-based nanomaterials (Ce/Zeo-NMs) as a multifunctional mesoporous nanoenzyme were designed for inducing neuroprotection after ischaemic stroke by reducing dysfunction of the neurovascular unit (NVU). Ce@Zeo-NMs had the ability to adsorb excessive Zn²⁺ and showed mimetic enzymatic activities. As a result, Ce@Zeo-NMs protected against cerebral ischaemia and reduced the damage of NVU by improving the integrity of blood brain barrier (BBB) and inhibiting activation of microglia and astrocytes in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). These findings indicated that Ce@Zeo-NMs may serve as a therapeutic strategy for neuroprotection and functional recovery upon ischaemic stroke onset.

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.

Comprehensive Analysis of the Effect of 20(R)-Ginsenoside Rg3 on Stroke Recovery in Rats via the Integrative miRNA-mRNA Regulatory Network

MicroRNAs (miRNAs) are a class of small, endogenous, noncoding RNAs. Recent research has proven that miRNAs play an essential role in the occurrence and development of ischemic stroke. Our previous studies confirmed that 20(R)-ginsenosideRg3 [20(R)-Rg3] exerts beneficial effects on cerebral ischemia-reperfusion injury (CIRI), but its molecular mechanism has not been elucidated. In this study, we used high-throughput sequencing to investigate the differentially expressed miRNA and mRNA expression profiles of 20(R)-Rg3 preconditioning to ameliorate CIRI injury in rats and to reveal its potential neuroprotective molecular mechanism. The results show that 20(R)-Rg3 alleviated neurobehavioral dysfunction in MCAO/R-treated rats. Among these mRNAs, 953 mRNAs were significantly upregulated and 2602 mRNAs were downregulated in the model group versus the sham group, whereas 437 mRNAs were significantly upregulated and 35 mRNAs were downregulated in the 20(R)-Rg3 group in contrast with those in the model group. Meanwhile, the expression profile of the miRNAs showed that a total of 283 differentially expressed miRNAs were identified, of which 142 miRNAs were significantly upregulated and 141 miRNAs were downregulated in the model group compared with the sham group, whereas 34 miRNAs were differentially expressed in the 20(R)-Rg3 treatment group compared with the model group, with 28 miRNAs being significantly upregulated and six miRNAs being significantly downregulated. Furthermore, 415 (391 upregulated and 24 downregulated) differentially expressed mRNAs and 22 (17 upregulated and 5 downregulated) differentially expressed miRNAs were identified to be related to 20(R)-Rg3's neuroprotective effect on stroke recovery. The Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that 20(R)-Rg3 could modulate multiple signaling pathways related to these differential miRNAs, such as the cGMP-PKG, cAMP and MAPK signaling pathways. This study provides new insights into the protective mechanism of 20(R)-Rg3 against CIRI, and the mechanism may be partly associated with the regulation of brain miRNA expression and its target signaling pathways.

Oxidative Injury in Ischemic Stroke: A Focus on NADPH Oxidase 4

Ischemic stroke is a leading cause of disability and mortality worldwide. Thus, it is urgent to explore its pathophysiological mechanisms and find new therapeutic strategies for its successful treatment. The relationship between oxidative stress and ischemic stroke is increasingly appreciated and attracting considerable attention. ROS serves as a source of oxidative stress. It is a byproduct of mitochondrial metabolism but primarily a functional product of NADPH oxidases (NOX) family members. Nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) is most closely related to the formation of ROS during ischemic stroke. Its expression is significantly upregulated after cerebral ischemia, making it a promising target for treating ischemic stroke. Several drugs targeting NOX4, such as SCM-198, Iso, G-Rb1, betulinic acid, and electroacupuncture, have shown efficacy as treatments of ischemic stroke. MTfp-NOX4 POC provides a novel insight for the treatment of stroke. Combinations of these therapies also provide new approaches for the therapy of ischemic stroke. In this review, we summarize the subcellular location, expression, and pathophysiological mechanisms of NOX4 in the occurrence and development of ischemic stroke. We also discuss the therapeutic strategies and related regulatory mechanisms for treating ischemic stroke. We further comment on the shortcomings of current NOX4-targeted therapy studies and the direction for improvement.

Nutraceuticals in HIV and COVID-19-Related Neurological Complications: Opportunity to Use Extracellular Vesicles as Drug Delivery Modality

Simple Summary

In this review, we discuss the potential use of extracellular vesicles (EVs) to deliver dietary supplements to the brain to reduce brain complications associated with HIV, COVID-19, and other brain disorders. Brain-related complications affect people with HIV and COVID-19 alike. Moreover, since HIV patients are at a higher risk of contracting COVID-19, their neurological problems can be exacerbated by COVID-19. The use of dietary supplements together with available treatment options has been shown to reduce the severity of infections. However, these treatments are not chemically compatible with the body’s blood–brain barrier defense mechanism. Therefore, a viable delivery method is needed to deliver drugs and nutraceuticals to the brain in HIV and COVID-19 comorbid patients.

Abstract

People living with HIV/AIDS (PLWHA) are at an increased risk of severe and critical COVID-19 infection. There is a steady increase in neurological complications associated with COVID-19 infection, exacerbating HIV-associated neurocognitive disorders (HAND) in PLWHA. Nutraceuticals, such as phytochemicals from medicinal plants and dietary supplements, have been used as adjunct therapies for many disease conditions, including viral infections. Appropriate use of these adjunct therapies with antiviral proprieties may be beneficial in treating and/or prophylaxis of neurological complications associated with these co-infections. However, most of these nutraceuticals have poor bioavailability and cannot cross the blood–brain barrier (BBB). To overcome this challenge, extracellular vesicles (EVs), biological nanovesicles, can be used. Due to their intrinsic features of biocompatibility, stability, and their ability to cross BBB, as well as inherent homing capabilities, EVs hold immense promise for therapeutic drug delivery to the brain. Therefore, in this review, we summarize the potential role of different nutraceuticals in reducing HIV- and COVID-19-associated neurological complications and the use of EVs as nutraceutical/drug delivery vehicles to treat HIV, COVID-19, and other brain disorders.

New Promising Therapeutic Avenues of Curcumin in Brain Diseases

Curcumin, the dietary polyphenol isolated from Curcuma longa (turmeric), is commonly used as an herb and spice worldwide. Because of its bio-pharmacological effects curcumin is also called "spice of life", in fact it is recognized that curcumin possesses important proprieties such as anti-oxidant, anti-inflammatory, anti-microbial, antiproliferative, anti-tumoral, and anti-aging. Neurodegenerative diseases such as Alzheimer's Diseases, Parkinson's Diseases, and Multiple Sclerosis are a group of diseases characterized by a progressive loss of brain structure and function due to neuronal death; at present there is no effective treatment to cure these diseases. The protective effect of curcumin against some neurodegenerative diseases has been proven by in vivo and in vitro studies. The current review highlights the latest findings on the neuroprotective effects of curcumin, its bioavailability, its mechanism of action and its possible application for the prevention or treatment of neurodegenerative disorders.

Lipid-Based Nanovesicular Drug Delivery Systems

In designing a new drug, considering the preferred route of administration, various requirements must be fulfilled. Active molecules pharmacokinetics should be reliable with a valuable drug profile as well as well-tolerated. Over the past 20 years, nanotechnologies have provided alternative and complementary solutions to those of an exclusively pharmaceutical chemical nature since scientists and clinicians invested in the optimization of materials and methods capable of regulating effective drug delivery at the nanometer scale. Among the many drug delivery carriers, lipid nano vesicular ones successfully support clinical candidates approaching such problems as insolubility, biodegradation, and difficulty in overcoming the skin and biological barriers such as the blood-brain one. In this review, the authors discussed the structure, the biochemical composition, and the drug delivery applications of lipid nanovesicular carriers, namely, niosomes, proniosomes, ethosomes, transferosomes, pharmacosomes, ufasomes, phytosomes, catanionic vesicles, and extracellular vesicles.

Special delEVery: Extracellular Vesicles as Promising Delivery Platform to the Brain

The treatment of central nervous system (CNS) pathologies is severely hampered by the presence of tightly regulated CNS barriers that restrict drug delivery to the brain. An increasing amount of data suggests that extracellular vesicles (EVs), i.e., membrane derived vesicles that inherently protect and transfer biological cargoes between cells, naturally cross the CNS barriers. Moreover, EVs can be engineered with targeting ligands to obtain enriched tissue targeting and delivery capacities. In this review, we provide a detailed overview of the literature describing a natural and engineered CNS targeting and therapeutic efficiency of different cell type derived EVs. Hereby, we specifically focus on peripheral administration routes in a broad range of CNS diseases. Furthermore, we underline the potential of research aimed at elucidating the vesicular transport mechanisms across the different CNS barriers. Finally, we elaborate on the practical considerations towards the application of EVs as a brain drug delivery system.

Super-Assembled Periodic Mesoporous Organosilica Frameworks for Real-Time Hypoxia-Triggered Drug Release and Monitoring

Hypoxia, induced by inadequate oxygen supply, is a key indication of various major illnesses, which necessitates the need to develop new nanoprobes capable of sensing hypoxia environments for the targeted system monitoring and drug delivery. Herein, we report a hypoxia-responsive, periodic mesoporous organosilica (PMO) nanocarrier for repairing hypoxia damage. β-cyclodextrin (β-CD) capped azobenzene functionalization on the PMO surface could be effectively cleaved by azoreductase under a hypoxia environment. Moreover, the nanosystem is equipped with fluorescence resonance energy transfer (FRET) pair (tetrastyrene derivative (TPE) covalently attached to the PMO framework as the donor and Rhodamine B (RhB) in the mesopores as the receptor) for intracellular visualization and tracking of drug release in real-time. The design of intelligent nanocarriers capable of simultaneous reporting and treating of hypoxia conditions highlights a great potential in the biomedical domain.

Hydroxysafflor Yellow A and Anhydrosafflor Yellow B Protect Against Cerebral Ischemia/Reperfusion Injury by Attenuating Oxidative Stress and Apoptosis via the Silent Information Regulator 1 Signaling Pathway

Hydroxysafflor yellow A (HSYA) and anhydrosafflor yellow B (AHSYB) are the main water-soluble compounds in Carthamus tinctorius L. However, studies on the effect of AHSYB on cerebral ischemia/reperfusion (I/R) injury and the therapeutic effect of HSYA by regulating silent information regulator 1 (SIRT1) pathway remain obscure. In this study, we investigated whether the neuroprotective effects of HSYA and AHSYB on oxygen-glucose deprivation/reoxygenation in primary-cultured hippocampal neuronal cells and the middle cerebral artery occlusion and reperfusion model in rats are associated with the regulation of the SIRT1 pathway. In vitro, HSYA and AHSYB increased cell viability, depressed oxidation properties, and reduced neuronal cell apoptosis. In vivo results showed that HSYA and AHSYB effectively reduced infarct volume, improved neurological function, suppressed apoptosis, and decreased the oxidative stress reaction. Besides, RT-PCR and Western blot analysis showed that HSYA and AHSYB increased the mRNA and protein expressions of the main factors in the SIRT1 pathway, including SIRT1, forkhead box O (FOXO) 1, and peroxisome proliferator–activated receptor coactivator 1α (PGC1α), decreased the expression of Bax, and increased the expression of Bcl-2. The results from immunohistochemistry also showed that the expressions of SIRT1, FOXO1, and PGC1α were increased after treatment with HSYA and AHSYB. Furthermore, the neuroprotective effects of HSYA and AHSYB were abolished by EX527 (SIRT1–specific inhibitor). These results indicated that HSYA and AHSYB should be developed into potential drugs for treating cerebral I/R injury via the SIRT1 pathway. Although HSYA and AHSYB have different chemical structures, both of them exert similar neuroprotective properties against I/R injury in vitro and in vivo, which means that AHSYB is also a non-negligible component in safflower.

Irisin Rescues Blood-Brain Barrier Permeability following Traumatic Brain Injury and Contributes to the Neuroprotection of Exercise in Traumatic Brain Injury

Traumatic brain injury (TBI) has a high incidence, mortality, and morbidity all over the world. One important reason for its poor clinical prognosis is brain edema caused by blood-brain barrier (BBB) dysfunction after TBI. The mechanism may be related to the disorder of mitochondrial morphology and function of neurons in damaged brain tissue, the decrease of uncoupling protein 2 (UCP2) activity, and the increase of inflammatory reaction and oxidative stress. In this study, we aimed to investigate the effects of exogenous irisin on BBB dysfunction after TBI and its role in the neuroprotective effects of endurance exercise (EE) in mice. The concentrations of irisin in cerebrospinal fluid (CSF) and plasma of patients with mild to severe TBI were measured by ELISA. Then, male C57BL/6J mice and UCP2 knockout mice with C57BL/6J background were used to establish the TBI model. The BBB structure and permeability were examined by transmission electron microscopy and Evans blue extravasation, respectively. The protein expressions of irisin, occludin, claudin-5, zonula occludens-1 (ZO-1), nuclear factor E2-related factor 2(Nrf2), quinine oxidoreductase (NQO-1), hemeoxygenase-1 (HO-1), cytochrome C (Cyt-C), cytochrome C oxidase (COX IV), BCL2-associated X protein (Bax), cleaved caspase-3, and UCP2 were detected by western blot. The production of reactive oxygen species (ROS) was evaluated by the dihydroethidium (DHE) staining. The levels of inflammatory factors were detected by ELISA. In this study, we found that the CSF irisin levels were positively correlated with the severity of disease in patients with TBI and both EE and exogenous irisin could reduce BBB damage in a mouse model of TBI. In addition, we used UCP2-/- mice and further found that irisin could improve the dysfunction of BBB after TBI by promoting the expression of UCP2 on the mitochondrial membrane of neurons, reducing the damage of mitochondrial structure and function, thus alleviating the inflammatory response and oxidative stress. In conclusion, the results of this study suggested that irisin might alleviate brain edema after TBI by promoting the expression of UCP2 on the mitochondrial membrane of neurons and contribute to the neuroprotection of EE against TBI.

Biomimetic silibinin-loaded macrophage-derived exosomes induce dual inhibition of Aβ aggregation and astrocyte activation to alleviate cognitive impairment in a model of Alzheimer's disease

Alzheimer's disease (AD) is a common neurodegenerative disease of the central nervous system. Due to its complex pathogenesis and the difficulty of drugs to cross the blood brain barrier (BBB), no effective clinical drugs are currently available that prevent the development of the course of AD. Silibinin (Slb) is known to exert dual therapeutic effects on reducing amyloid-β (Aβ) aggregation and deactivating astrocytes to improve behaviour and cognitive performance in subjects with Alzheimer's disease (AD). However, the poor brain targeting ability and low bioavailability limit its wide application. We aimed to encapsulate Slb in macrophage-derived exosomes (Exo-Slb) to improve its brain targeting ability. After entering the brain, exosomal Slb selectively interacted with Aβ monomers to reduce its aggregation. At the same time, Exo-Slb was internalized in astrocytes to inhibit their activation and alleviate astrocyte inflammation-mediated neuronal damage. Finally, Exo-Slb potently ameliorated cognitive deficits in AD mice.

Exosomes Engineering and Their Roles as Therapy Delivery Tools, Therapeutic Targets, and Biomarkers

Exosomes are becoming increasingly important therapeutic biomaterials for use in a variety of therapeutic applications due to their unique characteristics, especially due to the ineffectiveness and cytotoxicity of some existing therapies and synthetic therapeutic nanocarriers. They are highly promising as carriers of drugs, genes, and other therapeutic agents that can be incorporated into their interior or onto their surface through various modification techniques to improve their targeting abilities. In addition, they are biocompatible, safe, and stable. The review focuses on different types of exosomes and methods of their preparation, including the incorporation of different kinds of cargo, especially for drug delivery purposes. In particular, their importance and effectiveness as delivery vehicles of various therapeutic agents for a variety of therapeutic applications, including different diseases and disorders such as cancer treatment, cardiovascular and neurodegenerative diseases, are emphasized. Administration routes of exosomes into the body are also included. A novelty in the article is the emphasis on global companies that are already successfully developing and testing such therapeutic biomaterials, with a focus on the most influential ones. Moreover, a comparison of the advantages and disadvantages of the various methods of exosome production is summarized for the first time.

Exosomes as cell-derivative carriers in the diagnosis and treatment of central nervous system diseases

Exosomes are extracellular vesicles with the diameter ranging from 50 to 100 nm and are found in different body fluids such as blood, cerebrospinal fluid (CSF), urine and saliva. Like in case of various diseases, based on the parent cells, the content of exosomes (protein, mRNA, miRNA, DNA, lipids and metabolites) varies and thus can be utilized as potential biomarker for diagnosis and prognosis of the brain diseases. Furthermore, utilizing the natural potential exosomes to cross the blood–brain barrier and by specifically decorating it with the ligand as per the desired brain sites therapeutics can be delivered to brain parenchyma. This review article conveys the importance of exosomes and their use in the treatment and diagnosis of brain/central nervous system diseases.

Extracellular vesicles as a drug delivery system: A systematic review of preclinical studies

During the past decades, extracellular vesicles (EVs) have emerged as an attractive drug delivery system. Here, we assess their pre-clinical applications, in the form of a systematic review. For each study published in the past decade, disease models, animal species, EV donor cell types, active pharmaceutical ingredients (APIs), EV surface modifications, API loading methods, EV size and charge, estimation of EV purity, presence of biodistribution studies and administration routes were quantitatively analyzed in a defined and reproducible way. We have interpreted the trends we observe over the past decade, to define the niches where to apply EVs for drug delivery in the future and to provide a basis for regulatory guidelines.

Curcuminoid-Tailored Interfacial Free Energy of Hydrophobic Fibers for Enhanced Biological Properties

The ability of mimicking the extracellular matrix architecture has gained electrospun scaffolds a prominent space into the tissue engineering field. The high surface-to-volume aspect ratio of nanofibers increases their bioactivity while enhancing the bonding strength with the host tissue. Over the years, numerous polyesters, such as poly(lactic acid) (PLA), have been consolidated as excellent matrices for biomedical applications. However, this class of polymers usually has a high hydrophobic character, which limits cell attachment and proliferation, and therefore decreases biological interactions. In this way, functionalization of polyester-based materials is often performed in order to modify their interfacial free energy and achieve more hydrophilic surfaces. Herein, we report the preparation, characterization, and in vitro assessment of electrospun PLA fibers with low contents (0.1 wt %) of different curcuminoids featuring π-conjugated systems, and a central β-diketone unit, including curcumin itself. We evaluated the potential of these materials for photochemical and biomedical purposes. For this, we investigated their optical properties, water contact angle, and surface features while assessing their in vitro behavior using SH-SY5Y cells. Our results demonstrate the successful generation of homogeneous and defect-free fluorescent fibers, which are noncytotoxic, exhibit enhanced hydrophilicity, and as such greater cell adhesion and proliferation toward neuroblastoma cells. The unexpected tailoring of the scaffolds' interfacial free energy has been associated with the strong interactions between the PLA hydrophobic sites and the nonpolar groups from curcuminoids, which indicate its role for releasing hydrophilic sites from both parts. This investigation reveals a straightforward approach to produce photoluminescent 3D-scaffolds with enhanced biological properties by using a polymer that is essentially hydrophobic combined with the low contents of photoactive and multifunctional curcuminoids.

Exploring interactions between extracellular vesicles and cells for innovative drug delivery system design

Extracellular vesicles (EVs) are submicron cell-secreted structures containing proteins, nucleic acids and lipids. EVs can functionally transfer these cargoes from one cell to another to modulate physiological and pathological processes. Due to their presumed biocompatibility and capacity to circumvent canonical delivery barriers encountered by synthetic drug delivery systems, EVs have attracted considerable interest as drug delivery vehicles. However, it is unclear which mechanisms and molecules orchestrate EV-mediated cargo delivery to recipient cells. Here, we review how EV properties have been exploited to improve the efficacy of small molecule drugs. Furthermore, we explore which EV surface molecules could be directly or indirectly involved in EV-mediated cargo transfer to recipient cells and discuss the cellular reporter systems with which such transfer can be studied. Finally, we elaborate on currently identified cellular processes involved in EV cargo delivery. Through these topics, we provide insights in critical effectors in the EV-cell interface which may be exploited in nature-inspired drug delivery strategies.

SS-31 Protects Liver from Ischemia-Reperfusion Injury via Modulating Macrophage Polarization

Ischemia-reperfusion injury (IRI) is a common complication in liver surgeries. It is a focus to discover effective treatments to reduce ischemia-reperfusion injury. Previous studies show that oxidative stress and inflammation response contribute to the liver damage during IRI. SS-31 is an innovated mitochondrial-targeted antioxidant peptide shown to scavenge reactive oxygen species and decrease oxidative stress, but the protective effects of SS-31 against hepatic IRI are not well understood. The aim of our study is to investigate whether SS-31 could protect the liver from damages induced by IRI and understand the protective mechanism. The results showed that SS-31 treatment can significantly attenuate liver injury during IRI, proved by HE staining, serum ALT/AST, and TUNEL staining which can assess the degree of liver damage. Meanwhile, we find that oxidative stress and inflammation were significantly suppressed after SS-31 administration. Furthermore, the mechanism revealed that SS-31 can directly decrease ROS production and regulate STAT1/STAT3 signaling in macrophages, thus inhibiting macrophage M1 polarization. The proinflammation cytokines are then significantly reduced, which suppress inflammation response in the liver. Taken together, our study discovered that SS-31 can regulate macrophage polarization through ROS scavenging and STAT1/STAT3 signaling to ameliorate liver injury; the protective effects against hepatic IRI suggest that SS-31 may be an appropriate treatment for liver IRI in the clinic.