The colossal role of H-MnO2-PEG in ischemic stroke

Gas Therapy: Generating, Delivery, and Biomedical Applications

Oxygen (O2), nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H2S), and hydrogen (H2) with direct effects, and carbon dioxide (CO2) with complementary effects on the condition of various diseases are known as therapeutic gases. The targeted delivery and in situ generation of these therapeutic gases with controllable release at the site of disease has attracted attention to avoid the risk of gas poisoning and improve their performance in treating various diseases such as cancer therapy, cardiovascular therapy, bone tissue engineering, and wound healing. Stimuli-responsive gas-generating sources and delivery systems based on biomaterials that enable on-demand and controllable release are promising approaches for precise gas therapy. This work highlights current advances in the design and development of new approaches and systems to generate and deliver therapeutic gases at the site of disease with on-demand release behavior. The performance of the delivered gases in various biomedical applications is then discussed.

Polymeric nanocarriers delivery systems in ischemic stroke for targeted therapeutic strategies

Ischemic stroke is a complex, high-mortality disease with multifactorial etiology and pathogenesis. Currently, drug therapy is mainly used treat ischemic stroke in clinic, but there are still some limitations, such as limited blood-brain barrier (BBB) penetration efficiency, a narrow treatment time window and drug side effects. Recent studies have pointed out that drug delivery systems based on polymeric nanocarriers can effectively improve the insufficient treatment for ischemic stroke. They can provide neuronal protection by extending the plasma half-life of drugs, enhancing the drug's permeability to penetrate the BBB, and targeting specific structures and cells. In this review, we classified polymeric nanocarriers used for delivering ischemic stroke drugs and introduced their preparation methods. We also evaluated the feasibility and effectiveness and discussed the existing limitations and prospects of polymeric nanocarriers for ischemic stroke treatment. We hoped that this review could provide a theoretical basis for the future development of nanomedicine delivery systems for the treatment of ischemic stroke.

The blood-brain barrier: structure, regulation, and drug delivery

Blood-brain barrier (BBB) is a natural protective membrane that prevents central nervous system (CNS) from toxins and pathogens in blood. However, the presence of BBB complicates the pharmacotherapy for CNS disorders as the most chemical drugs and biopharmaceuticals have been impeded to enter the brain. Insufficient drug delivery into the brain leads to low therapeutic efficacy as well as aggravated side effects due to the accumulation in other organs and tissues. Recent breakthrough in materials science and nanotechnology provides a library of advanced materials with customized structure and property serving as a powerful toolkit for targeted drug delivery. In-depth research in the field of anatomical and pathological study on brain and BBB further facilitates the development of brain-targeted strategies for enhanced BBB crossing. In this review, the physiological structure and different cells contributing to this barrier are summarized. Various emerging strategies for permeability regulation and BBB crossing including passive transcytosis, intranasal administration, ligands conjugation, membrane coating, stimuli-triggered BBB disruption, and other strategies to overcome BBB obstacle are highlighted. Versatile drug delivery systems ranging from organic, inorganic, and biologics-derived materials with their synthesis procedures and unique physio-chemical properties are summarized and analyzed. This review aims to provide an up-to-date and comprehensive guideline for researchers in diverse fields, offering perspectives on further development of brain-targeted drug delivery system.

Perspective insights into hydrogels and nanomaterials for ischemic stroke

Ischemic stroke (IS) is a neurological disorder prevalent worldwide with a high disability and mortality rate. In the clinic setting, tissue plasminogen activator (tPA) and thrombectomy could restore blood flow of the occlusion region and improve the outcomes of IS patients; however, these therapies are restricted by a narrow time window. Although several preclinical trials have revealed the molecular and cellular mechanisms underlying infarct lesions, the translatability of most findings is unsatisfactory, which contributes to the emergence of new biomaterials, such as hydrogels and nanomaterials, for the treatment of IS. Biomaterials function as structural scaffolds or are combined with other compounds to release therapeutic drugs. Biomaterial-mediated drug delivery approaches could optimize the therapeutic effects based on their brain-targeting property, biocompatibility, and functionality. This review summarizes the advances in biomaterials in the last several years, aiming to discuss the therapeutic potential of new biomaterials from the bench to bedside. The promising prospects of new biomaterials indicate the possibility of an organic combination between materialogy and medicine, which is a novel field under exploration.

Nanocarrier-Based Drug Delivery to Brain: Interventions of Surface Modification

Brain disorders are a prevalent and rapidly growing problem in the medical field as they adversely affect the quality of life of a human. With an increase in life expectancy, it has been reported that diseases like Alzheimer's, Parkinson's, stroke and brain tumors, along with neuropsychological disorders, are also being reported at an alarmingly high rate. Despite various therapeutic methods for treating brain disorders, drug delivery to the brain has been challenging because of a very complex Blood Brain Barrier, which precludes most drugs from entering the brain in effective concentrations. Nano-carrier-based drug delivery systems have been reported widely by researchers to overcome this barrier layer. These systems due to their small size, offer numerous advantages; however, their short residence time in the body owing to opsonization hinders their success in vivo. This review article focuses on the various aspects of modifying the surfaces of these nano-carriers with polymers, surfactants, protein, antibodies, cell-penetrating peptides, integrin binding peptides and glycoproteins such as transferrin & lactoferrin leading to enhanced residence time, desirable characteristics such as the ability to cross the blood-brain barrier (BBB), increased bioavailability in regions of the brain and targeted drug delivery.

Thrombus Inhibition and Neuroprotection for Ischemic Stroke Treatment through Platelet Regulation and ROS Scavenging

Ischemic stroke is caused by cerebrovascular stenosis or occlusion. Excessive reactive oxygen species (ROS) are the focus-triggering factor of irreversible injury in ischemic regions, which result in harmful cascading effects to brain tissue, such as inflammation and microthrombus formation. In the present work, we designed nanodelivery systems (NDSs) based on MnO₂ loaded with Ginkgolide B (GB) for restoring the intracerebral microenvironment in ischemic stroke, such as ROS scavenging, O₂ elevation, thrombus inhibition and damage repair. GB can activate the endogenous antioxidant defense of cells by enhancing the nuclear factor-E2-related factor 2 (Nrf2) signalling pathway, thus protecting brain tissue from oxidative damage. However, the blood-brain barrier (BBB) is also a therapeutic obstacle for the delivery of these agents to ischemic regions. MnO₂ nanoparticles have an inherent BBB penetration effect, which enhances the delivery of therapeutic agents within brain tissue. MnO₂ , with mimicking enzymatic activity, can catalyze the decomposition of overproduced H₂ O₂ in the ischemic microenvironment to O₂ , meanwhile releasing platelet-antagonizing GB molecules, thus alleviating cerebral hypoxia, oxidative stress damage, and microthrombus generation. This study may provide a promising therapeutic route for regulating the microenvironment of ischemic stroke through a combined function of ROS scavenging, microthrombus inhibition, and BBB penetration.

Chitosan-modified hollow manganese dioxide nanoparticles loaded with resveratrol for the treatment of spinal cord injury

Spinal cord injury (SCI) is a serious central nervous system disease, and secondary injury, including oxidative stress, the inflammatory response and accompanying neuronal apoptosis, will aggravate the condition. Due to the existence of the blood–spinal cord barrier (BSCB), the existing drugs for SCI treatment are difficulty to reach the injury site and thus their efficacy is limited. In this study, we designed chitosan-modified hollow manganese dioxide nanoparticles (CM) for the delivery of resveratrol to help it pass through the BSCB. Resveratrol (Res), a poorly soluble drug, was adsorbed into CM with a particle size of approximately 130 nm via the adsorption method, and the drug loading reached 21.39 ± 2.53%. In vitro dissolution experiment, the Res release of the loaded sample (CMR) showed slowly release behavior and reached about 87% at 36 h. In vitro at the cellular level and in vivo at the animal level experiments demonstrated that CMR could alleviate significantly oxidative stress by reducing level of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and increasing glutathione peroxidase (GSH) level. Additionally, immunofluorescence (iNOS, IL-1β, and Cl caspase-3) and western blot (iNOS, cox-2, IL-1β, IL-10, Cl caspase-3, bax, and bcl-2) were used to detect the expression of related factors, which verified that CMR could also reduce inflammation and neuronal apoptosis. These results indicated that CM, as a potential central nervous system drug delivery material, was suitable for SCI treatment.

Progress in Stimuli-Responsive Biomaterials for Treating Cardiovascular and Cerebrovascular Diseases

Cardiovascular and cerebrovascular diseases (CCVDs) describe abnormal vascular system conditions affecting the brain and heart. Among these, ischemic heart disease and ischemic stroke are the leading causes of death worldwide, resulting in 16% and 11% of deaths globally. Although several therapeutic approaches are presented over the years, the continuously increasing mortality rates suggest the need for more advanced strategies for their treatment. One of these strategies lies in the use of stimuli-responsive biomaterials. These "smart" biomaterials can specifically target the diseased tissue, and after "reading" the altered environmental cues, they can respond by altering their physicochemical properties and/or their morphology. In this review, the progress in the field of stimuli-responsive biomaterials for CCVDs in the last five years, aiming at highlighting their potential as early-stage therapeutics in the preclinical scenery, is described.

Advances in the research of nano delivery systems in ischemic stroke

Ischemic stroke is the most common type of cerebrovascular disease with high disability rate and mortality. The blood-brain barrier (BBB) protects the homeostasis of the brain's microenvironment and impedes the penetration of 98% of drugs. Therefore, effective treatment requires the better drug transport across membranes and increased drug distribution. Nanoparticles are a good choice for drugs to cross BBB. The main pathways of nano delivery systems through BBB include passive diffusion, adsorption-mediated endocytosis, receptor-mediated transport, carrier-mediated transport, etc. At present, the materials used in brain-targeted delivery can be divided into natural polymer, synthetic polymers, inorganic materials and phospholipid. In this review, we first introduced several ways of nano delivery systems crossing the BBB, and then summarized their applications in ischemic stroke. Based on their potential and challenges in the treatment of ischemic stroke, new ideas and prospects are proposed for designing feasible and effective nano delivery systems.

The Promotional Effect of Hollow MnO2 with Brucea Javanica Oil Emulsion (BJOE) on Endometrial Cancer Apoptosis

Endometrial cancer (EC) is a common gynecological malignancy worldwide whose therapy mainly depends on chemotherapy. In past years, an increasing number of studies indicate that hollow MnO2 could serve as a nanoplatform in the drug delivery system. The Brucea javanica oil emulsion (BJOE) has been illustrated to play a vital role in cancers. However, knowledge about the combined effect of H-MnO2-PEG/BJOE in endometrial cancer remains ambiguous up to now. In the present work, we prepared a drug-delivery vector H-MnO2-PEG by chemical synthesis and found that H-MnO2-PEG significantly inhibited cell proliferation in endometrial cancer cells. Moreover, the combination of H-MnO2-PEG/BJOE could repress cell proliferation more efficiently and promote cell apoptosis. Mechanistically, we found that BJOE exerted its role as a promoter of endometrial apoptosis by regulating relative protein expressions. In general, the present study demonstrates that H-MnO2-PEG functions as a critical vector in the tumor microenvironment of endometrial cancer and the significant effect of H-MnO2-PEG/BJOE on cancer cells, suggesting a new paradigm for the treatment of endometrial cancer.