Intravenous Administration of Cilostazol Nanoparticles Ameliorates Acute Ischemic Stroke in a Cerebral Ischemia/Reperfusion-Induced Injury Model

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.

Carbohydrate-Derived Polytriazole Nanoparticles Enhance the Anti-Inflammatory Activity of Cilostazol

Poly(amide-triazole) and poly(ester-triazole) synthesized from d-galactose as a renewable resource were applied for the synthesis of nanoparticles (NPs) by the emulsification/solvent evaporation method. The NPs were characterized as stable, spherical particles, and none of their components, including the stabilizer poly(vinyl alcohol), were cytotoxic for normal rat kidney cells. These NPs proved to be useful for the efficient encapsulation of cilostazol (CLZ), an antiplatelet and vasodilator drug currently used for the treatment of intermittent claudication, which is associated with undesired side-effects. In this context, the nanoencapsulation of CLZ was expected to improve its therapeutic administration. The carbohydrate-derived polymeric NPs were designed taking into account that the triazole rings of the polymer backbone could have attractive interactions with the tetrazole ring of CLZ. The activity of the nanoencapsulated CLZ was measured using a matrix metalloproteinase model in a lipopolysaccharide-induced inflammation system. Interestingly, the encapsulated drug exhibited enhanced anti-inflammatory activity in comparison with the free drug. The results are very promising since the stable, noncytotoxic NP systems efficiently reduced the inflammation response at low CLZ doses. In summary, the NPs were obtained through an innovative methodology that combines a carbohydrate-derived synthetic polymer, designed to interact with the drug, ease of preparation, adequate biological performance, and environmentally friendly production.

Minoxidil Nanoparticles Targeting Hair Follicles Enhance Hair Growth in C57BL/6 Mice

We previously found that 1% minoxidil (MXD) nanoparticles prepared using a bead mill method led to an increase I n hair follicle delivery and hair growth in C57BL/6 mice. In the present study, we designed a nanoparticle formulation containing 5% MXD (MXD-NPs) using the bead mill method and investigated the hair-growth effect of MXD-NPs and a commercially available MXD solution (CA-MXD). Hair growth and in vivo permeation studies were conducted using C57BL/6 mice. Moreover, we examined the MXD contents in the upper (hair bulge) and the lower hair follicle (hair bulb) and observed the hair follicle epithelial stem cells (HFSC) by immunohistochemical staining using the CD200 antibody. The mean particle size of the MXD in the MXD-NPs was 139.8 nm ± 8.9 nm. The hair-growth effect of the MXD-NPs was higher than that of CA-MXD, and the MXD content in the hair bulge of mice treated with MXD-NPs was 7.4-fold that of the mice treated with CA-MXD. In addition, the activation of HFSC was observed around the bulge in the MXD-NPs-treated mice. We showed that MXD-NPs enable the accumulation of MXD in the upper hair follicles more efficiently than CA-MXD, leading the activation of HFSC and the hair growth.

A Systematic Approach to the Development of Cilostazol Nanosuspension by Liquid Antisolvent Precipitation (LASP) and Its Combination with Ultrasound

Nanosizing is an approach to improve the dissolution rate of poorly soluble drugs. The first aim of this work was to develop nanosuspension of cilostazol with liquid antisolvent precipitation (LASP) and its combination with ultrasound. Second, to systematically study the effect of bottom-up processing factors on precipitated particles’ size and identify the optimal settings for the best reduction. After solvent and stabilizer screening, in-depth process characterization and optimization was performed using Design of Experiments. The work discusses the influence of critical factors found with statistical analysis: feed concentration, stabilizer amount, stirring speed and ultrasound energy governed by time and amplitude. LASP alone only generated particle size of a few microns, but combination with ultrasound was successful in nanosizing (d10 = 0.06, d50 = 0.33, d90 = 1.45 µm). Micro- and nanosuspension’s stability, particle morphology and solid state were studied. Nanosuspension displayed higher apparent solubility than equilibrium and superior dissolution rate over coarse cilostazol and microsuspension. A bottom-up method of precipitation-sonication was demonstrated to be a successful approach to improve the dissolution characteristics of poorly soluble, BCS class II drug cilostazol by reducing its particle size below micron scale, while retaining nanosuspension stability and unchanged crystalline form.

Nanoparticles-mediated emerging approaches for effective treatment of ischemic stroke

Ischemic stroke leads to high disability and mortality. The limited delivery efficiency of most therapeutic substances is a major challenge for effective treatment of ischemic stroke. Inspired by the prominent merit of nanoscale particles in brain targeting and blood-brain barrier (BBB) penetration, various functional nanoparticles have been designed as promising drug delivery platforms that are expected to improve the therapeutic effect of ischemic stroke. Based on the complex pathological mechanisms of ischemic stroke, this review outline and summarize the rationally designed nanoparticles-mediated emerging approaches for effective treatment of ischemic stroke, including recanalization therapy, neuroprotection therapy, and combination therapy. On this bases, the potentials and challenges of nanoparticles in the treatment of ischemic stroke are revealed, and new thoughts and perspectives are proposed for the design of feasible nanoparticles for effective treatment of ischemic stroke.

Transdermal System Based on Solid Cilostazol Nanoparticles Attenuates Ischemia/Reperfusion-Induced Brain Injury in Mice

Cilostazol (CIL) exerted a protective effect by promoting blood-brain barrier integrity as well as improving the status of neurological dysfunctions following cerebral ischemia/reperfusion (I/R) injury. We attempted to design a 0.5% CIL carbopol gel using solid nanoparticles (CIL-Ngel), and then investigated the relationships between energy-dependent endocytosis and the skin penetration of CIL-Ngel in this study. In addition, we evaluated whether the CIL-Ngel attenuated I/R-induced brain injury in a middle cerebral artery occlusion (MCAO)/reperfusion model mouse. The particle size of CIL was decreased using a bead mill, and the CIL particles (14.9 × 10¹⁴ particles/0.3 g) in the CIL-Ngel were approximately 50-180 nm. The release of CIL in the CIL-Ngel was higher than that in gel containing CIL powder (CIL-Mgel), and the CIL particles were released from the CIL-Ngel as nanoparticles. In addition, the percutaneous absorption of CIL from the CIL-Ngel was higher in comparison with that from CIL-Mgel, and clathrin-dependent endocytosis and caveolae-dependent endocytosis were related to the enhanced skin penetration of CIL-NPs. In the traditional (oral administration of CIL powder, 3 mg/kg) and transdermal administration (CIL-Ngel, 0.3 g) for 3 days (once a day), the area under the plasma CIL concentration-time curves (AUC) was similar, although the CIL supplied to the blood by the CIL-Ngel was more sustained than that via oral administration of CIL powder. Furthermore, the CIL-Ngel attenuated the ischemic stroke. In conclusion, we designed a gel using solid CIL-NPs, and we showed that the sustained release of CIL by CIL-Ngel provided an effective treatment for ischemic stroke in MCAO/reperfusion model mice. These findings induce the possibilities of developing novel applications of CIL solid nanoparticles.

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

Stroke is one of the most serious problems that seriously affect people's health and brings huge economic burden to society. The development of new nanocarriers with desired degradability and targeted ability is of great significance for efficient drug delivery. In recent years, nano drug delivery system has developed rapidly and applied to treat ischemic stroke. Here, we report the synthesis and functionalization of monodisperse hollow structured MnO₂ (H-MnO₂). The highly monodisperse H-MnO₂ with uniform morphology was obtained by in situ growing MnO₂ on solid silica nanoparticles and subsequently removing the silica core. After successive modification of poly ethylene glycol(PEG), we further verified their protective effect on ischemic stroke in our study.

Ischemic Postconditioning Reduces NMDA Receptor Currents Through the Opening of the Mitochondrial Permeability Transition Pore and KATP Channel in Mouse Neurons

Ischemic postconditioning (PostC) is known to reduce cerebral ischemia/reperfusion (I/R) injury; however, whether the opening of mitochondrial ATP-dependent potassium (mito-K_ATP) channels and mitochondrial permeability transition pore (mPTP) cause the depolarization of the mitochondrial membrane that remains unknown. We examined the involvement of the mito-K_ATP channel and the mPTP in the PostC mechanism. Ischemic PostC consisted of three cycles of 15 s reperfusion and 15 s re-ischemia, and was started 30 s after the 7.5 min ischemic load. We recorded N-methyl-D-aspartate receptors (NMDAR)-mediated currents and measured cytosolic Ca²⁺ concentrations, and mitochondrial membrane potentials in mouse hippocampal pyramidal neurons. Both ischemic PostC and the application of a mito-K_ATP channel opener, diazoxide, reduced NMDAR-mediated currents, and suppressed cytosolic Ca²⁺ elevations during the early reperfusion period. An mPTP blocker, cyclosporine A, abolished the reducing effect of PostC on NMDAR currents. Furthermore, both ischemic PostC and the application of diazoxide potentiated the depolarization of the mitochondrial membrane potential. These results indicate that ischemic PostC suppresses Ca²⁺ influx into the cytoplasm by reducing NMDAR-mediated currents through mPTP opening. The present study suggests that depolarization of the mitochondrial membrane potential by opening of the mito-K_ATP channel is essential to the mechanism of PostC in neuroprotection against anoxic injury.

Biomaterials to Neuroprotect the Stroke Brain: A Large Opportunity for Narrow Time Windows

Ischemic stroke represents one of the most prevalent pathologies in humans and is a leading cause of death and disability. Anti-thrombolytic therapy with tissue plasminogen activator (t-PA) and surgical thrombectomy are the primary treatments to recanalize occluded vessels and normalize the blood flow in ischemic and peri-ischemic regions. A large majority of stroke patients are refractory to treatment or are not eligible due to the narrow time window of therapeutic efficacy. In recent decades, we have significantly increased our knowledge of the molecular and cellular mechanisms that inexorably lead to progressive damage in infarcted and peri-lesional brain areas. As a result, promising neuroprotective targets have been identified and exploited in several stroke models. However, these considerable advances have been unsuccessful in clinical contexts. This lack of clinical translatability and the emerging use of biomaterials in different biomedical disciplines have contributed to developing a new class of biomaterial-based systems for the better control of drug delivery in cerebral disorders. These systems are based on specific polymer formulations structured in nanoparticles and hydrogels that can be administered through different routes and, in general, bring the concentrations of drugs to therapeutic levels for prolonged times. In this review, we first provide the general context of the molecular and cellular mechanisms impaired by cerebral ischemia, highlighting the role of excitotoxicity, inflammation, oxidative stress, and depolarization waves as the main pathways and targets to promote neuroprotection avoiding neuronal dysfunction. In the second part, we discuss the versatile role played by distinct biomaterials and formats to support the sustained administration of particular compounds to neuroprotect the cerebral tissue at risk of damage.

Novel Sustained-Release Drug Delivery System for Dry Eye Therapy by Rebamipide Nanoparticles

The commercially available rebamipide ophthalmic suspension (CA-REB) was approved for clinical use in patients with dry eye; however, the residence time on the ocular surface for the traditional formulations is short, since the drug is removed from the ocular surface through the nasolacrimal duct. In this study, we designed a novel sustained-release drug delivery system (DDS) for dry eye therapy by rebamipide nanoparticles. The rebamipide solid nanoparticle-based ophthalmic formulation (REB-NPs) was prepared by a bead mill using additives (2-hydroxypropyl-β-cyclodextrin and methylcellulose) and a gel base (carbopol). The rebamipide particles formed are ellipsoid, with a particle size in the range of 40-200 nm. The rebamipide in the REB-NPs applied to eyelids was delivered into the lacrimal fluid through the meibomian glands, and sustained drug release was observed in comparison with CA-REB. Moreover, the REB-NPs increased the mucin levels in the lacrimal fluid and healed tear film breakup levels in an N-acetylcysteine-treated rabbit model. The information about this novel DDS route and creation of a nano-formulation can be used to design further studies aimed at therapy for dry eye.

The Intravitreal Injection of Lanosterol Nanoparticles Rescues Lens Structure Collapse at an Early Stage in Shumiya Cataract Rats

We designed an intravitreal injection formulation containing lanosterol nanoparticles (LAN-NPs) via the bead mill method and evaluated the therapeutic effect of LAN-NPs on lens structure collapse and opacification using two rat cataract models (SCR-N, rats with slight lens structure collapse; SCR-C, rats with the combination of a remarkable lens structure collapse and opacification). The particle size of lanosterol in the LAN-NPs was around 50–400 nm. A single injection of LAN-NPs (0.5%) supplied lanosterol into the lens for 48 h, and no irritation or muddiness was observed following repeated injections of LAN-NPs for 6 weeks (once every 2 days). Moreover, LAN-NPs repaired the slight collapse of the lens structure in SCR-N. Although the remarkable changes in the lens structure of SCR-C were not repaired by LAN-NP, the onset of opacification was delayed. In addition, the increase of cataract-related factors (Ca²⁺ contents, nitric oxide levels, lipid peroxidation and calpain activity levels) in the lenses of SCR-C was attenuated by the repeated injection of LAN-NPs. It is possible that a deficiency of lanosterol promotes the production of oxidative stress. In conclusion, it is difficult to improve serious structural collapse with posterior movement of the lens nucleus with a supplement of lanosterol via LAN-NPs. However, the intravitreal injection of LAN-NPs was found to repair the space and structural collapse in the early stages in the lenses.

Novel approaches for the delivery of therapeutics in ischemic stroke

Here, we review novel approaches to deliver neuroprotective drugs to salvageable penumbral brain areas of stroke injury with the goals of offsetting ischemic brain injury and enhancing recovery.

Solid Nanocrystals of Rebamipide Promote Recovery from Indomethacin-Induced Gastrointestinal Bleeding

Indomethacin (IMC)-induced gastrointestinal (GI) injuries are more common in rheumatoid arthritis (RA) patients than in other IMC users, and the overexpression of nitric oxide (NO) via inducible NO synthase (iNOS) is related to the seriousness of IMC-induced GI injuries. However, sufficient strategies to prevent IMC-induced GI injuries have not yet been established. In this study, we designed dispersions of rebamipide (RBM) solid nanocrystals (particle size: 30–190 nm) by a bead mill method (RBM-NDs), and investigated whether the oral administration of RBM-NDs is useful to prevent IMC-induced GI injuries. The RBM nanocrystals were spherical and had a solubility 4.71-fold greater than dispersions of traditional RBM powder (RBM-TDs). In addition, the RBM-NDs were stable for 1 month after preparation. The RBM contents in the stomach, jejunum, and ileum of rats orally administered RBM-NDs were significantly higher than in rats administered RBM-TDs. Moreover, the oral administration of RBM-NDs decreased the NO levels via iNOS and area of the GI lesions in IMC-stimulated RA (adjuvant-induced arthritis rat) rats in comparison with the oral administration of RBM-TDs. Thus, we show that the oral administration of RBM-NDs provides a high drug supply to the GI mucosa, resulting in a therapeutic effect on IMC-induced GI injuries. Solid nanocrystalline RBM preparations may offer effective therapy for RA patients.

Drug Delivery System Based On Minoxidil Nanoparticles Promotes Hair Growth In C57BL/6 Mice

Purpose

We designed formulations based on minoxidil (MXD) nanoparticles (N-MXD) and examined whether N-MXD can increase drug delivery into the follicles. In addition, we investigated the effect of N-MXD on hair growth in C57BL/6 mice.

Methods

N-MXD (1%) was prepared as follows: methylcellulose, p-hydroxyalkylbenzoates, mannitol, and MXD were dispersed in purified water and milled using zirconia beads under refrigeration (5500 rpm, 30 s×15 times, intermittent milling). C57BL/6 mice were used to evaluate hair-growth effects. The expression levels of mRNA and protein for vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) were determined by real-time PCR and ELISA methods, respectively.

Results

The ratio of solid-MXD was approximately 60% in N-MXD, and the MXD nanoparticles (90-300 nm) were oblong in shape. For the design of nanomedicines, usability is important. Therefore, we measured the stability and toxicity after N-MXD treatment. No agglutination of MXD nanoparticles was detected for 2 weeks, and no redness or MXD powder residue was observed in the skin after repetitive applications of N-MXD. Next, we evaluated hair-growth effects by N-MXD treatment. MXD contents in the skin tissue from N-MXD were lower than for commercially available MXD formulations (CA-MXD). Conversely, MXD contents in the hair bulbs were higher for N-MXD than for CA-MXD, and the drug efficacy of N-MXD was also higher than that of CA-MXD. In addition, the mRNA and protein levels of IGF-1 and VEGF were enhanced by the repetitive application of N-MXD and CA-MXD, and the enhanced IGF-1 and VEGF levels were significantly higher for N-MXD than for CA-MXD.

Conclusion

We designed a novel nanomedicine based on MXD nanoparticles and showed that N-MXD can deliver MXD into hair bulbs via hair follicles and that the therapeutic efficiency for hair growth is higher than for CA-MXD (solution type).

The Potential of Biomaterial-Based Approaches as Therapies for Ischemic Stroke: A Systematic Review and Meta-Analysis of Pre-clinical Studies

Background: In recent years pre-clinical stroke research has shown increased interest in the development of biomaterial-based therapies to promote tissue repair and functional recovery. Such strategies utilize biomaterials as structural support for tissue regeneration or as delivery vehicles for therapeutic agents. While a range of biomaterials have been tested in stroke models, currently no overview is available for evaluating the benefit of these approaches. We therefore performed a systematic review and meta-analysis of studies investigating the use of biomaterials for the treatment of stroke in experimental animal models. Methods: Studies were identified by searching electronic databases (PubMed, Web of Science) and reference lists of relevant review articles. Studies reporting lesion volume and/or neurological score were included. Standardized mean difference (SMD) and 95% confidence intervals were calculated using DerSimonian and Laird random effects. Study quality and risk of bias was assessed using the CAMARADES checklist. Publication bias was visualized by funnel plots followed by trim and fill analysis of missing publications. Results: A total of 66 publications were included in the systematic review, of which 44 (86 comparisons) were assessed in the meta-analysis. Overall, biomaterial-based interventions improved both lesion volume (SMD: -2.98, 95% CI: -3.48, -2.48) and neurological score (SMD: -2.3, 95% CI: -2.85, -1.76). The median score on the CAMARADES checklist was 5.5/10 (IQR 4.25-6). Funnel plots of lesion volume and neurological score data revealed pronounced asymmetry and publication bias. Additionally, trim and fill analysis estimated 19 "missing" studies for the lesion volume outcome adjusting the effect size to -1.91 (95% CI: -2.44, -1.38). Conclusions: Biomaterials including scaffolds and particles exerted a positive effect on histological and neurological outcomes in pre-clinical stroke models. However, heterogeneity in the field, publication bias and study quality scores which may be another source of bias call for standardization of outcome measures and improved study reporting.

Protective effect of edaravone on blood-brain barrier by affecting NRF-2/HO-1 signaling pathway

Protective effect of edaravone on blood-brain barrier (BBB) in experimental cerebral infarction rats was investigated. SD rats were prepared as the permanent middle cerebral artery occlusion model and randomly divided into 4 groups: cerebral infarction model group, edaravone low, medium and high dose groups. Healthy rats only for operation and no filament were selected as the sham operation control group. Rats in the cerebral infarction model group and the control group were given normal saline, and those in the edaravone low, medium and high dose groups were given edaravone 10, 15 and 20 mg/kg, respectively. The survival status, the body weight and neurological function score before and after treatment, the brain water content and the permeability of the blood-brain barrier after treatment were measured. The expression levels of NFE2-related factor 2 (NRF2) and hemeoxygenase 1 (HO-1) in rat brain tissue were detected by western blotting. Levels of peripheral blood malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) were detected by ELISA. The state of the rats in three edaravone groups was improved compared with that of the cerebral infarction group. Compared with the cerebral infarction model group, the body weight was significantly increased after treatment and the neurological function score, brain tissue water content and BBB permeability were significantly decreased in three edaravone groups (P<0.05). Compared with the model group of cerebral infarction, the expression of NRF-2 and HO-1 in the brain of the three edaravone groups was significantly higher (P<0.05). Compared with the model group of cerebral infarction, the expression of MDA and GSH in the three edaravone groups was significantly decreased, GSH and SOD was increased (P<0.05), in a dose-dependent manner. Edaravone might play a protective role in the BBB by activating the NRF-2/HO-1 signaling pathway.

A window into the brain: Tools to assess pre-clinical efficacy of biomaterials-based therapies on central nervous system disorders

Therapeutic conveyance into the brain is a cardinal requirement for treatment of diverse central nervous system (CNS) disorders and associated pathophysiology. Effectual shielding of the brain by the blood-brain barrier (BBB) sieves out major proportion of therapeutics with the exception of small lipophilic molecules. Various nano-delivery systems (NDS) provide an effective solution around this obstacle owing to their small size and targeting properties. To date, these systems have been used for several pre-clinical disease models including glioma, neurodegenerative diseases and psychotic disorders. An efficacy screen for these systems involves a test battery designed to probe into the multiple facets of therapeutic delivery. Despite their wide application in redressing various disease targets, the efficacy evaluation strategies for all can be broadly grouped into four modalities, namely: histological, bio-imaging, molecular and behavioural. This review presents a comprehensive insight into all of these modalities along with their strengths and weaknesses as well as perspectives on an ideal design for a panel of tests to screen brain nano-delivery systems.

Therapeutic Potential of a Combination of Magnesium Hydroxide Nanoparticles and Sericin for Epithelial Corneal Wound Healing

We previously found the instillation of sericin to be useful as therapy for keratopathy with or without diabetes mellitus. In this study, we investigated whether a combination of solid magnesium hydroxide nanoparticles (MHN) enhances epithelial corneal wound healing by sericin using rabbits, normal rats and type 2 diabetes mellitus rats with debrided corneal epithelium (ex vivo and in vivo studies). Ophthalmic formulations containing sericin and MHN (N-Ser) were prepared using a bead mill method. The mean particle size of the N-Ser was 110.3 nm at the time of preparation, and 148.1 nm one month later. The instillation of N-Ser had no effect on the amount of lacrimal fluid in normal rabbits (in vivo), but the MHN in N-Ser was found to expand the intercellular space in ex vivo rat corneas. In addition, the instillation of N-Ser increased the phosphorylation of Extracellular Signal-regulated Kinase (ERK)1/2, a factor involved in cell adhesion and cell proliferation in the corneal epithelium, in comparison with the instillation of sericin alone. The combination with MHN enhanced epithelial corneal wound healing by sericin in rat debrided corneal epithelium (in vivo). This study provides significant information to prepare potent drugs to cure severe keratopathy, such as diabetic keratopathy.

Energy-Dependent Endocytosis is Involved in the Absorption of Indomethacin Nanoparticles in the Small Intestine

We previously reported that oral formulations containing indomethacin nanoparticles (IND-NPs) showed high bioavailability, and, consequently, improved therapeutic effects and reduced injury to the small intestine. However, the pathway for the transintestinal penetration of nanoparticles remained unclear. Thus, in this study, we investigated whether endocytosis was related to the penetration of IND-NPs (72.1 nm) using a transcell set with Caco-2 cells or rat intestine. Four inhibitors of various endocytosis pathways were used [nystatin, caveolae-dependent endocytosis (CavME); dynasore, clathrin-dependent endocytosis (CME); rottlerin, macropinocytosis; and cytochalasin D, phagocytosis inhibitor], and all energy-dependent endocytosis was inhibited at temperatures under 4 °C in this study. Although IND-NPs showed high transintestinal penetration, no particles were detected in the basolateral side. IND-NPs penetration was strongly prevented at temperatures under 4 °C. In experiments using pharmacological inhibitors, only CME inhibited penetration in the jejunum, while in the ileum, both CavME and CME significantly attenuated penetration. In conclusion, we found a novel pathway for the transintestinal penetration of drug nanoparticles. Our hypothesis was that nanoparticles would be taken up into the intestinal epithelium by endocytosis (CME in jejunum, CavME and CME in ileum), and dissolved and diffused in the intestine. Our findings are likely to be of significant use for the development of nanomedicines.

Nanoparticle-Based Therapeutics for Brain Injury

Brain injuries affect a large patient population with major physical and emotional suffering for patients and their relatives; at a significant cost to the society. Effective diagnostic and therapeutic options available for brain injuries are limited by the complex brain injury pathology involving blood-brain barrier (BBB). Brain injuries, including ischemic stroke and brain trauma, initiate BBB opening for a short period of time, which is followed by a second reopening for an extended time. The leaky BBB and/or the alterations in the receptor expression on BBB may provide opportunities for therapeutic delivery via nanoparticles (NPs). The approaches for therapeutic interventions via NP delivery are aimed at salvaging the pericontusional/penumbra area for possible neuroprotection and neurovascular unit preservation. The focus of this progress report is to provide a survey of NP strategies employed in cerebral ischemia and brain trauma and finally provide insights for improved NP-based diagnostic/treatment approaches.

Ophthalmic Formulation Containing Nilvadipine Nanoparticles Prevents Retinal Dysfunction in Rats Injected with Streptozotocin

Retinopathy leads to irreparable vision loss via capillary closure and areas of nonperfusion. However, the current instillation systems do not allow a sufficient amount of drug required to treat retinopathy to reach the posterior segment (retina); therefore, a new formulation targeting the posterior segment is expected as therapy for retinopathy. We prepared ophthalmic formulations containing nilvadipine nanoparticles (NIL_nano), and demonstrated whether the instillation of NIL_nano can prevent retinal dysfunction in rats injected with excessive streptozotocin (STZ rats) in this study. NIL_nano (mean particle size, 77 nm) was prepared by wet bead mill treatment, with the inclusion of various additives (2-hydroxypropyl-β-cyclodextrin, benzalkonium chloride, d-mannitol, and methylcellulose). Retinal dysfunction was observable two weeks after rats received intraperitoneal injections of streptozotocin (100 mg/kg × 2, consecutive days, STZ rat). Changes in retinal function were evaluated by electroretinogram (ERG) and immunological methods. The retinal thickness, measured as the distance between the ganglion cell layer and the distal border of the outer nuclear layer, increased two weeks after the injection of streptozotocin, resulting in decreases in the levels of a-waves, b-waves, and oscillatory potential amplitudes in ERG of rats. The instillation of NIL_nano allowed the topical supplement of nilvadipine into the retina, and repeated instillation of NIL_nano (2 times/day) attenuated the retinal disorders led by the excessive streptozotocin. In conclusion, we found that retinal dysfunction in rats injected with streptozotocin can be prevented by the NIL_nano instillation. These results are useful in further studies aimed at the therapeutic treatment of retinopathy.

An oral formulation of cilostazol nanoparticles enhances intestinal drug absorption in rats

Cilostazol (CLZ) is an anti-platelet agent that is generally used after the onset of cerebral infarction. However, CLZ is a poorly water-soluble drug and a strategy for increasing its bioavailability is required. In the present study, novel oral formulations were designed containing CLZ solid nanoparticles to improve bioavailability. The present study investigated the therapeutic effect of the oral formulations containing CLZ nanoparticles on ischemic stroke using a cerebral ischemia/reperfusion-induced injury model (MCAO/reperfusion mice). The oral formulation containing CLZ nanoparticles (CLZ/R_nano tablet) was prepared using a combination of recrystallization and ball milling with the following ingredients: CLZ, docusate sodium, methylcellulose, 2-hydoxypropyl-β-cyclodextrin, gum arabic, polyvinylpyrrolidone, and mannitol. The particle size after re-dispersion of the CLZ/R_nano tablet was 64±47 nm (mean ± standard deviation). The CLZ areas under the concentration-time curve (AUC) and mean residence time (MRT) in rats that were administered CLZ/R_nano tablets were significantly greater compared with those in rats that were administered CLZ/R_micro tablets. Results indicated, the AUC after administration of CLZ/R_nano tablets was 3.1-fold higher compared with that after administration of the commercially available CLZ OD tablet. In addition, oral administration with CLZ/R_nano tablets ameliorated neurological deficits caused by ischemic stroke in MCAO/reperfusion mice. It is possible that the oral formulation containing CLZ nanoparticles will be useful for the treatment of patients with ischemic stroke and that these findings will provide significant information that can be used to improve the drug with low bioavailability.

Therapeutic Effect of Cilostazol Ophthalmic Nanodispersions on Retinal Dysfunction in Streptozotocin-Induced Diabetic Rats

We previously prepared ophthalmic formulations containing cilostazol (CLZ) nanoparticles by bead mill methods (CLZ_nano), and found that instillation of CLZ_nano into rat eyes supplies CLZ into the retina. In this study, we investigated changes in the electroretinograms (ERG) of streptozotocin-induced diabetic rats (STZ rats), a model of diabetes mellitus. In addition, we demonstrated that dispersions containing CLZ nanoparticles attenuate changes in the ERG of STZ rats. The instillation of CLZ_nano had no effect on body weight or plasma glucose and insulin levels. Furthermore, no corneal toxicity was observed in the in vivo study using STZ rats. The a-wave and b-wave levels in addition to oscillatory potentials (OP) amplitude decreased in STZ rats two weeks after the injection of streptozotocin, with the instillation of CLZ_nano attenuating these decreases. In addition, the level of vascular endothelial growth factor (VEGF) in the retinas of STZ rats was 9.26-fold higher than in in normal rats, with this increase also prevented by the instillation of CLZ_nano Thus, we have found that a-wave and b-wave levels in addition to OP amplitude are decreased in rats following the injection of excessive streptozotocin. Furthermore, the retinal disorders associated with diabetes mellitus are attenuated by the instillation of CLZ_nano. These findings provide significant information that can be used to design further studies aimed at developing anti-diabetic retinopathy drugs.

Cilostazol protects mice against myocardium ischemic/reperfusion injury by activating a PPARγ/JAK2/STAT3 pathway

Myocardial ischemia/reperfusion (MIR) injury causes severe arrhythmias and a high lethality. The present study is designed to investigate the effect of cilostazol on MIR injury and the underlying mechaism. We measured the effects of cilostazol on heart function parameters in a mouse model of MIR. Proinflammatory cytokines and apoptosis proteins in the myocardium were examined to investigate the anti-inflammatory and anti-apoptosis ability of cilostazol. The participation of PPARγ/JAK2/STAT3 pathway was investigated. Results showed that the impairment of hemodynamic parameters caused by MIR was attenuated by cilostazol. The IL-6, IL-1β and TNF-a levels were all decreased by cilostazol. Cilostazol also significantly inhibited Bax and cleaved caspase-3 levels and restored the Bcl-2 levels. PPARγ, JAK2 and STAT3 were all activated by cilostazol. Treatment of inhibitors of them abolished the protective effects of cilostazol on cardiac function, myocardial inflammation and apoptosis. In summary, cilostazol alleviated the cardiac function impairment, myocardial inflammation and apoptosis induced by MIR. The results present a novel signaling mechanism that cilostazol protects MIR injury by activating a PPARγ/JAK2/STAT3 pathway.

Improved thrombolytic effect with focused ultrasound and neuroprotective agent against acute carotid artery thrombosis in rat

Combination therapy with focused ultrasound (FUS) and a neuroprotective agent, BNG-1, was examined in an acute carotid thrombotic occlusion model using LED irradiation in rat to improve the thrombolytic effect of rt-PA. Seven treatment groups included (A) intravenous bolus injection of 0.45 mg/kg rt-PA, (B) intravenous bolus injection of 0.9 mg/kg, (C) sonothrombolysis with FUS alone, (D) oral administration of 2 g/kg BNG-1 for 7 days alone, (E) A + D, (F) A + C, and (G) A + C + D. Four comparison groups were made including (H) 0.45 mg/kg rt-PA 20% bolus +80% IV fusion + FUS, (I) 0.9 mg/kg rt-PA with 10% bolus + 90% intravenous fusion, (J) B + C, (K) B + D. At 7 days after carotid occlusion, small-animal carotid ultrasound and 7 T MR angiography showed the recanalization rate of ≤50% stenosis was 50% in group B and 83% in group I, but 0% in groups A and C and 17% in group D. Combination therapy improved recanalization rate to 50–63% in groups E and F, to 67–83% in groups J and K, and to 100% in groups G and H. Our study demonstrated combination therapy with different remedies can be a feasible strategy to improve the thrombolytic effect of rt-PA.

Induction of Ischemic Stroke and Ischemia-reperfusion in Mice Using the Middle Artery Occlusion Technique and Visualization of Infarct Area

Cerebrovascular disease is highly prevalent in the global population and encompasses several types of conditions, including stroke. To study the impact of stroke on tissue injury and to evaluate the effectiveness of therapeutic interventions, several experimental models in a variety of species were developed. They include complete global cerebral ischemia, incomplete global ischemia, focal cerebral ischemia, and multifocal cerebral ischemia. The model described in this protocol is based on the middle cerebral artery occlusion (MCAO) and is related to the focal ischemia category. This technique produces consistent focal ischemia in a strictly defined region of the hemisphere and is less invasive than other methods. The procedure described is performed on mice, given the availability of several genetic variants and the high number of tests standardized for mice to aid in the behavioral and neurodeficit evaluation.

Evaluation of Neuroprotective Effect of Thymoquinone Nanoformulation in the Rodent Cerebral Ischemia-Reperfusion Model

The purpose of the present study was to evaluate the neuroprotective efficacy of optimized thymoquinone loaded PLGA-chitosan nanoparticles delivered via nose to brain route in the rodent cerebral ischemia-reperfusion model. The neuroprotective efficacy of the optimized thymoquinone loaded PLGA-chitosan nanoparticles was evaluated in middle cerebral artery occluded rats by various pharmacodynamic and biochemical studies. The pharmacokinetics of thymoquinone loaded PLGA-chitosan nanoparticles in the brain and blood plasma together with qualitative localization of florescent labelled PLGA-chitosan nanoparticles in brain tissues were also determined. Intranasal delivery of optimized thymoquinone loaded PLGA-chitosan nanoparticles (183.5 ± 8.2 nm, 33.63 ± 2.25 mV) to brain significantly reduced the ischemia infarct volume and enhanced the locomotor activity and grip strength in the middle cerebral artery occluded rats. Biochemical studies showed that intranasal delivery of thymoquinone loaded PLGA-chitosan nanoparticles significantly reduced the lipid peroxidation but elevated the glutathione, catalase, and superoxide dismutase in the brain of middle cerebral artery occluded rats. The pharmacokinetic and localization studies showed that thymoquinone loaded PLGA-chitosan nanoparticles facilitated the delivery of thymoquinone to brain by intranasal nose to brain transport pathways and enhanced their pharmacokinetic profile in brain tissues. Thus, intranasal delivery of thymoquinone loaded PLGA-chitosan nanoparticles to brain could be potentially used for the neuroprotection and treatment of cerebral ischemia.