Safe and efficient drug delivery system with liposomes for intrathecal application of an antivasospastic drug, fasudil

Drug delivery in leptomeningeal disease: Navigating barriers and beyond

Leptomeningeal disease (LMD) refers to the infiltration of cancer cells into the leptomeningeal compartment. Leptomeninges are the two membranous layers, called the arachnoid membrane and pia mater. The diffuse nature of LMD poses a challenge to its effective diagnosis and successful management. Furthermore, the predominant phenotype; solid masses or freely floating cells, has altering implications on the effectiveness of drug delivery systems. The standard of care is the intrathecal delivery of chemotherapy drugs but it is associated with increased instances of treatment-related complications, low patient compliance, and suboptimal drug distribution. An alternative involves administering the drugs systemically, after which they must traverse fluid barriers to arrive at their destination within the leptomeningeal space. However, this route is known to cause off-target effects as well as produce subtherapeutic drug concentrations at the target site within the central nervous system. The development of new drug delivery systems such as liposomal cytarabine has improved drug delivery in leptomeningeal metastatic disease, but much still needs to be done to effectively target this challenging condition. In this review, we discuss about the anatomy of leptomeninges relevant for drug penetration, the conventional and advanced drug delivery methods for LMD. We also discuss the future directions being set by different clinical trials.

Skin drug delivery using lipid vesicles: A starting guideline for their development

Lipid vesicles can provide a cost-effective enhancement of skin drug absorption when vesicle production process is optimised. It is an important challenge to design the ideal vesicle, since their properties and features are related, as changes in one affect the others. Here, we review the main components, preparation and characterization methods commonly used, and the key properties that lead to highly efficient vesicles for transdermal drug delivery purposes. We stand by size, deformability degree and drug loading, as the most important vesicle features that determine the further transdermal drug absorption. The interest in this technology is increasing, as demonstrated by the exponential growth of publications on the topic. Although long-term preservation and scalability issues have limited the commercialization of lipid vesicle products, freeze-drying and modern escalation methods overcome these difficulties, thus predicting a higher use of these technologies in the market and clinical practice.

Transcriptome analysis of fasudil treatment in the APPswe/PSEN1dE9 transgenic (APP/PS1) mice model of Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of progressive dementia. In the present study, we showed hippocampal tissue transcriptome analysis in APPswe/PSEN1dE9 (APP/PS1, AD model) mice treated with fasudil (ADF) and compared with AD mice treated with saline (ADNS) and wild type mice (WT). The competing endogenous RNA (ceRNA) network was constructed and validated the differential expression of mRNA, lncRNA, miRNA, and circRNA. Our study showed differentially expressed mRNAs (DEMs) between WT and ADNS, while enriched in cell growth and death and nervous system pathways. DEMs between ADNS-ADF were enriched in the nervous system, glycosaminoglycan biosynthesis-keratan sulfate (KS) and Quorum sensing pathways. We validated four genes with RT-PCR, whereas enrichment of Acyl-CoA Synthetase Long Chain Family Member 4 (Acsl4, ENSMUST00000112903) in Quorum sensing pathways, and BTG anti-proliferation factor 1 (Btg1, ENSMUST00000038377) in RNA degradation pathways were conducted. Expression of these two genes were higher in ADNS, but were significantly reduced in ADF. Histone H4 transcription factor (Hinfp, ENSMUST00000216508) orchestrate G1/S transition of mitotic cell cycle and co-expressed with mmu-miR-26a-2-3p-mediated ceRNA and mmu-miR-3065-5p-mediated ceRNA; Wnt family member 4 (Wnt4, ENSMUST00000045747) was enriched in mTOR, Hippo and Wnt signaling pathway. Expression of these two genes were significantly lower in ADNS, and fasudil treatment reverse it. The present studies demonstrated four genes: Acsl4, Btg1, Hinfp, Wnt4 could be potential biomarkers of AD and the targets of fasudil treatment. These results will pave a novel direction for future clinic studies for AD and fasudil treatment.

Pharmacokinetics of inhaled nanotherapeutics for pulmonary delivery

Pulmonary delivery of lipid-based nanotherapeutics by inhalation presents an advantageous alternative to oral and intravenous routes of administration that avoids enzymatic degradation in gastrointestinal tract and hepatic first pass metabolism and also limits off-target adverse side effects upon heathy tissues. For lung-related indications, inhalation provides localized delivery in order to enhance therapeutic efficacy at the site of action. Optimization of physicochemical properties, selected drug and inhalation format can greatly influence the pharmacokinetic behavior of inhaled nanoparticle systems and their payloads. The present review analyzes a wide range of nanoparticle systems, their formulations and consequent effect on pharmacokinetic distribution of delivered active components after inhalation.

Intrathecal drug delivery in the era of nanomedicine

Administration of substances directly into the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord is one approach that can circumvent the blood-brain barrier to enable drug delivery to the central nervous system (CNS). However, molecules that have been administered by intrathecal injection, which includes intraventricular, intracisternal, or lumbar locations, encounter new barriers within the subarachnoid space. These barriers include relatively high rates of turnover as CSF clears and potentially inadequate delivery to tissue or cellular targets. Nanomedicine could offer a solution. In contrast to the fate of freely administered drugs, nanomedicine systems can navigate the subarachnoid space to sustain delivery of therapeutic molecules, genes, and imaging agents within the CNS. Some evidence suggests that certain nanomedicine agents can reach the parenchyma following intrathecal administration. Here, we will address the preclinical and clinical use of intrathecal nanomedicine, including nanoparticles, microparticles, dendrimers, micelles, liposomes, polyplexes, and other colloidalal materials that function to alter the distribution of molecules in tissue. Our review forms a foundational understanding of drug delivery to the CSF that can be built upon to better engineer nanomedicine for intrathecal treatment of disease.

CAR, a Homing Peptide, Prolongs Pulmonary Preferential Vasodilation by Increasing Pulmonary Retention and Reducing Systemic Absorption of Liposomal Fasudil

Here, we sought to elucidate the role of CAR (a cyclic peptide) in the accumulation and distribution of fasudil, a drug for pulmonary arterial hypertension (PAH), in rat lungs and in producing pulmonary specific vasodilation in PAH rats. As such, we prepared liposomes of fasudil and CAR-conjugated liposomal fasudil and assessed the liposomes for CAR conjugation, physical properties, entrapment efficiencies, in vitro release profiles, and stabilities upon incubation in cell culture media, storage, and aerosolization. We also studied the cellular uptake of fasudil in different formulations, quantified heparan sulfate (HS) in pulmonary arterial smooth muscle cells (PASMCs), and investigated the distribution of the liposomes in the lungs of PAH rats. We assessed the drug accumulation in a close and recirculating isolated perfused rat lung model and studied the pharmacokinetics and pharmacological efficacy of the drug and formulations in Sugen/hypoxia-induced PAH rats. The entrapment efficiency of the liposomal fasudil was 95.5 ± 4.5%, and the cumulative release was 93.95 ± 6.22%. The uptake of CAR liposomes by pulmonary arterial cells and their distribution and accumulation in the lungs were much greater than those of no-CAR-liposomes. CAR-induced increase in the cellular uptake was associated with an increase in HS expression by rat PAH-PASMCs. CAR, when conjugated with liposomal fasudil and given via an intratracheal instillation, extended the elimination half-life of the drug by four-fold compared with fasudil-in-no-CAR-liposomes given via the same route. CAR-conjugated liposomal fasudil, as opposed to fasudil-in-no-CAR-liposomes and CAR pretreatment followed by fasudil-in-no-CAR-liposomes, reduced the mean pulmonary arterial pressure by 40-50% for 6 h, without affecting the mean systemic arterial pressure. On the whole, this study suggests that CAR aids in concentrating the drug in the lungs, increasing the cellular uptake, extending the half-life of fasudil, and eliciting a pulmonary-specific vasodilation when the peptide remains conjugated on the liposomal surface, but not when CAR is given as a pretreatment or alone as an admixture with the drug.

Protective effect of a novel Rho kinase inhibitor WAR-5 in experimental autoimmune encephalomyelitis by modulating inflammatory response and neurotrophic factors

The Rho-kinase (ROCK) inhibitor Fasudil has proven beneficial in experimental autoimmune encephalomyelitis (EAE). Given the small safety window of Fasudil, we are looking for novel ROCK inhibitors, which have similar or stronger effect on EAE with greater safety. In this study, we report that WAR-5, a Y-27632 derivative, alleviates the clinical symptoms, attenuates myelin damage and reduces CNS inflammatory responses in EAE C57BL/6 mice at an extent similar to Fasudil, while exhibits less vasodilator and adverse reaction in vivo. WAR-5 inhibits ROCK activity, and selectively suppresses the expression of ROCK II in spleen, brain and spinal cord of EAE mice, especially in spinal cord, accompanied by decreased expression of Nogo. WAR-5 also regulates the imbalance of Th1/Th17 T cells and regulatory T cells, inhibits inflammatory microenvironment induced with NF-κB-IL-1β pathway. Importantly, WAR-5 converts M1 toward M2 microglia/macrophages that are positively correlated with BDNF and NT-3 production. Taken together, WAR-5 exhibits therapeutic potential in EAE by more selectively inhibits ROCK II, with a greater safety than Fasudil, and is worthy of further clinical study to clarify its clinical value.

Axon growth inhibition by RhoA/ROCK in the central nervous system

Rho kinase (ROCK) is a serine/threonine kinase and a downstream target of the small GTPase Rho. The RhoA/ROCK pathway is associated with various neuronal functions such as migration, dendrite development, and axonal extension. Evidence from animal studies reveals that RhoA/ROCK signaling is involved in various central nervous system (CNS) diseases, including optic nerve and spinal cord injuries, stroke, and neurodegenerative diseases. Given that RhoA/ROCK plays a critical role in the pathophysiology of CNS diseases, the development of therapeutic agents targeting this pathway is expected to contribute to the treatment of CNS diseases. The RhoA/ROCK pathway mediates the effects of myelin-associated axon growth inhibitors—Nogo, myelin-associated glycoprotein (MAG), oligodendrocyte-myelin glycoprotein (OMgp), and repulsive guidance molecule (RGM). Blocking RhoA/ROCK signaling can reverse the inhibitory effects of these molecules on axon outgrowth, and promotes axonal sprouting and functional recovery in animal models of CNS injury. To date, several RhoA/ROCK inhibitors have been under development or in clinical trials as therapeutic agents for neurological disorders. In this review, we focus on the RhoA/ROCK signaling pathway in neurological disorders. We also discuss the potential therapeutic approaches of RhoA/ROCK inhibitors for various neurological disorders.

Fasudil improves short-term echocardiographic parameters of diastolic function in patients with type 2 diabetes with preserved left ventricular ejection fraction: a pilot study

Left ventricular (LV) diastolic dysfunction is observed frequently in patients with type 2 diabetes; however, few studies have focused on the effect of the Rho-associated kinase inhibitor fasudil on cardiac performance in humans. We conducted a prospective pilot study to assess the impact of fasudil on LV diastolic function in patients with diabetes without systolic dysfunction. Two hundred and fifty eligible patients with type 2 diabetes (149 men [61.3 %] and 94 women [38.7 %]) with a mean age of 57.2 years were randomly assigned to fasudil (n = 122, 30 mg intravenously twice a day for 14 days) or placebo (n = 121) groups. Echocardiographic variables were measured at the baseline and 1 month after the intervention. Compared with the placebo group, the fasudil group showed a significant decrease in diastolic blood pressure and in the peak of late diastolic transmitral flow (Am) (P < 0.05 for both). Deceleration time (DT), isovolumic relaxation time (IVRT), the peak of early diastolic annular velocity (e'), the peak of late diastolic annular velocity, and E/e' also exhibited a significant improvement (all, P < 0.05) after fasudil administration. Furthermore, the Em/Am ratio and IVRT, DT, and E/e' values recorded after fasudil treatment in the subgroup with impaired LV relaxation significantly differed from the corresponding values in the subgroup with normal LV relaxation (all, P < 0.05). Fasudil improves short-term echocardiographic parameters of LV diastolic function in patients with type 2 diabetes with preserved left ventricular ejection fraction.

The protective effect of fasudil on the structure and function of cardiac mitochondria from rats with type 2 diabetes induced by streptozotocin with a high-fat diet is mediated by the attenuation of oxidative stress

Dysfunction of cardiac mitochondria appears to play a substantial role in cardiomyopathy or myocardial dysfunction and is a promising therapeutic target for many cardiovascular diseases. We investigated the effect of the Rho/Rho-associated protein kinase (ROCK) inhibitor fasudil on cardiac mitochondria from rats in which diabetes was induced by a combination of streptozotocin (STZ) and a sustained high-fat diet. Eight weeks after diabetes was induced by a single intraperitoneal injection of 50 mg/kg STZ followed by a sustained high-fat diet, either fasudil (5 mg/kg bid) or equivalent volumes of saline (control) were administered over four weeks. Fasudil significantly protected against the histopathologic changes of cardiac mitochondria in diabetic rats. Fasudil significantly reduced the abundances of the Rho A, ROCK 1, and ROCK 2 proteins, restored the activities of succinate dehydrogenase (SDH) and monoamine oxidase (MAO) in cardiac mitochondria, inhibited the opening of the mitochondrial permeability transition pore, and decreased the total antioxidant capacity, as well as levels of malonyldialdehyde, hydroxy radical, reduced glutathione, and superoxide dismutase in heart. Fasudil improved the structures of cardiac mitochondria and increased both SDH and MAO activities in cardiac mitochondria. These beneficial effects may be associated with the attenuation of oxidative stress caused by fasudil treatment.

Intravitreal administration of HA-1077, a ROCK inhibitor, improves retinal function in a mouse model of huntington disease

Huntington disease (HD) is an inherited neurodegenerative disease that affects multiple brain regions. It is caused by an expanded polyglutamine tract in huntingtin (Htt). The development of therapies for HD and other neurodegenerative diseases has been hampered by multiple factors, including the lack of clear therapeutic targets, and the cost and complexity of testing lead compounds in vivo. The R6/2 HD mouse model is widely used for pre-clinical trials because of its progressive and robust neural dysfunction, which includes retinal degeneration. Profilin-1 is a Htt binding protein that inhibits Htt aggregation. Its binding to Htt is regulated by the rho-associated kinase (ROCK), which phosphorylates profilin at Ser-137. ROCK is thus a therapeutic target in HD. The ROCK inhibitor Y-27632 reduces Htt toxicity in fly and mouse models. Here we characterized the progressive retinopathy of R6/2 mice between 6–19 weeks of age to determine an optimal treatment window. We then tested a clinically approved ROCK inhibitor, HA-1077, administered intravitreally via liposome-mediated drug delivery. HA-1077 increased photopic and flicker ERG response amplitudes in R6/2 mice, but not in wild-type littermate controls. By targeting ROCK with a new inhibitor, and testing its effects in a novel in vivo model, these results validate the in vivo efficacy of a therapeutic candidate, and establish the feasibility of using the retina as a readout for CNS function in models of neurodegenerative disease.

Liposomal fasudil, a rho-kinase inhibitor, for prolonged pulmonary preferential vasodilation in pulmonary arterial hypertension

Current pharmacological interventions for pulmonary arterial hypertension (PAH) require continuous infusions, multiple inhalations, or oral administration of drugs that act on various pathways involved in the pathogenesis of PAH. However, invasive methods of administration, short duration of action, and lack of pulmonary selectivity result in noncompliance and poor patient outcomes. In this study, we tested the hypothesis that encapsulation of an investigational anti-PAH molecule fasudil (HA-1077), a Rho-kinase inhibitor, into liposomal vesicles results in prolonged vasodilation in distal pulmonary arterioles. Liposomes were prepared by hydration and extrusion method and fasudil was loaded by ammonium sulfate-induced transmembrane electrochemical gradient. Liposomes were then characterized for various physicochemical properties. Optimized formulations were tested for pulmonary absorption and their pharmacological efficacy in a monocrotaline (MCT) induced rat model of PAH. The entrapment efficiency of optimized liposomal fasudil formulations was between 68.1±0.8% and 73.6±2.3%, and the cumulative release at 37°C was 98-99% over a period of 5 days. Compared to intravenous (IV) fasudil, a ~10 fold increase in the terminal plasma half-life was observed when liposomal fasudil was administered as aerosols. The t1/2 of IV fasudil was 0.39±0.12 h. and when given as liposomes via pulmonary route, the t1/2 extended to 4.71±0.72 h. One h after intratracheal instillation of liposomal fasudil, mean pulmonary arterial pressure (MPAP) was reduced by 37.6±5.7% and continued to decrease for about 3 h, suggesting that liposomal formulations produced pulmonary preferential vasodilation in MCT induced PAH rats. Overall, this study established the proof-of-principle that aerosolized liposomal fasudil is a feasible option for a non-invasive, controlled release and pulmonary preferential treatment of PAH.

Comparison of intrathecal cilostazol and nimodipine treatments in subarachnoid hemorrhage: an experimental study in rabbits

OBJECTIVE

intrathecal administration of calcium channel antagonists has been proposed to reduce cerebral vasospasm (CVS) in animal subarachnoid hemorrhage (SAH) models. Also, delayed CVS treatment model with oral administration of cilostazol can be seen in the literature.

METHODS

in this study, 25 male New Zealand white rabbits were randomly assigned to five groups: control, SAH only, SAH/nimodipine, SAH/cilostazol, SAH/vehicle. The animals' basilar arteries were sectioned from four separate zones and four sections were obtained from each rabbit. Basilar artery luminal section areas were measured by using SPOT for windows Version 4.1 computer program.

RESULTS

basilar artery luminal section areas in SAH/ nimodipine and SAH/ cilostazol groups were significantly higher than SAH only group (P < 0.05).

CONCLUSION

phosphodiesterase 3 inhibitor cilostazol has vasodilatory effects without affecting cerebral blood flow. Nimodipine is a calcium channel blocker and is still used in vasospasm therapy either oral or intravenously. This study demonstrates that prophylactic bolus intrathecal administration of either cilostazol or nimodipine equally prevents SAH-associated CVS in an animal model. We therefore propose that cilostazol is a candidate for clinical trials in the treatment of delayed vasospasm.

Comparison of intrathecal flunarizine and nimodipine treatments in cerebral vasospasm after experimental subarachnoid hemorrhage in rabbits

BACKGROUND

the aim of this study was to assess and to compare the ability of intrathecal flunarizine and nimodipine to prevent vasospasm in a rabbit model of subarachnoid hemorrhage (SAH).

METHOD

forty male New Zealand white rabbits were allocated into 5 groups randomly. The treatment groups were as follows: (1) control (no SAH [n = 8]), (2) SAH only (n = 8), (3) SAH plus vehicle (n = 8), (4) SAH plus nimodipine (n = 8), and (5) SAH plus flunarizine (n = 8). Before sacrifice, all animals underwent femoral artery catheterization procedure by open surgery under anesthesia and angiography performed for each animal.

FINDINGS

there was a statistically significant difference between the mean basilar artery cross-sectional areas and the mean arterial wall thickness measurements of the control and SAH-only groups (p < 0.05). Basilar artery vessel diameter and luminal section areas in group 4 were significantly higher than in group 2 (p < 0.05). Basilar artery vessel diameter and basilar artery luminal section areas in group 5 were significantly higher than in group 2 (p < 0.05).Basilar artery vessel diameter and basilar artery luminal section areas in group 5 were significantly higher than in group 4 (p < 0.05).

CONCLUSIONS

these findings demonstrate that flunarizine has marked vasodilatatory effect in an experimental model of SAH in rabbits.

Simultaneous quantitative analysis of fasudil and its active metabolite in human plasma by liquid chromatography electro-spray tandem mass spectrometry

A fast and sensitive method to quantify fasudil hydrochloride (FH) and its active metabolite hydroxyfasudil (M3) in human plasma using HPLC-MS/MS has been developed and validated in present study. The method involved simple sample preparation with methanol as protein precipitation (3:1, v/v) and ranitidine as an internal standard (IS). The analytes and IS were separated using a gradient elution procedure on the analytical column ZORBAX StableBond-C18 (5 microm, 150 mm x 4.6mm). Detection was performed by an AB 3200 QTRAP tandem mass spectrometer equipped with a Turbo IonSpray ionization source set in positive ion mode. Multiple reaction monitoring (MRM) using the precursor to product ion was m/z 292.2/99.2 for fasudil, m/z 308.2/99.2 for M3 and m/z for 315.3/176.2 for IS. The linear range of the method was from 0.4 to 250 ng/mL for both fasudil and M3. The lower limit of quantification was 0.4 ng/mL for both fasudil and M3. The intra- and inter-day relative standard deviation over the entire concentration range was less than 7.11% for fasudil and 10.6% for M3, respectively. The validated method was successfully applied for the evaluation of pharmacokinetic of fasudil hydrochloride after administration of 30 mg fasudil hydrochloride by continuous intravenous infusion over 30 min in 12 healthy Chinese volunteers.

Subarachnoid hemorrhage and the distribution of drugs delivered into the cerebrospinal fluid. Laboratory investigation

OBJECT

Investigators in experimental and clinical studies have used the intrathecal route to deliver drugs to prevent or treat vasospasm. However, a clot near an artery or arteries after subarachnoid hemorrhage (SAH) may hamper distribution and limit the effects of intrathecally delivered compounds. In a primate model of right middle cerebral artery (MCA) SAH, the authors examined the distribution of Isovue-M 300 and 3% Evans blue after infusion into the cisterna magna CSF.

METHODS

Ten cynomolgus monkeys were assigned to SAH and sham SAH surgery groups (5 in each group). Monkeys received CSF injections as long as 28 days after SAH and were killed 3 hours after the contrast/Evans blue injection. The authors assessed the distribution of contrast material on serial CT within 2 hours after contrast injection and during autopsy within 3 hours after Evans blue staining.

RESULTS

Computed tomography cisternographies showed no contrast in the vicinity of the right MCA (p < 0.05 compared with left); the distribution of contrast surrounding the entire right cerebral hemisphere was substantially reduced. Postmortem analysis demonstrated much less Evans blue staining of the right hemisphere surface compared with the left. Furthermore, the Evans blue dye did not penetrate into the right sylvian fissure, which occurred surrounding the left MCA. The authors observed the same pattern of changes and differences in contrast distribution between SAH and sham SAH animals and between the right and the left hemispheres on Days 1, 3, 7, 14, 21, and 28 after SAH.

CONCLUSIONS

Intrathecal drug distribution is substantially limited by SAH. Thus, when using intrathecal drug delivery after SAH, vasoactive drugs are unlikely to reach the arteries that are at the highest risk of delayed cerebral vasospasm.

Involvement of Rho-kinase in tumor necrosis factor-alpha-induced interleukin-6 release from C6 glioma cells

Tumor necrosis factor (TNF)-alpha stimulated interleukin (IL)-6 release and induced the phosphorylation of myosin phosphatase targeting subunit (MYPT)-1, a Rho-kinase substrate. The IL-6 release was significantly suppressed by Y-27632 and fasudil, Rho-kinase inhibitors. Although IkappaB inhibitor suppressed the TNF-alpha-induced IL-6 release, the Rho-kinase inhibitors did not affect the TNF-alpha-induced IkappaB phosphorylation. TNF-alpha induced the phosphorylation of p38 mitogen-activated protein (MAP) kinase, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK), and p44/p42 MAP kinase. The TNF-alpha-induced IL-6 release was suppressed by SB203580, a p38 MAPK inhibitor, or SP600125, a SAPK/JNK inhibitor, but not by PD98059, a MAP kinase/extracellular signal-regulated kinase kinase inhibitor. The Rho-kinase inhibitors attenuated the TNF-alpha-induced phosphorylation of both p38 MAP kinase and SAPK/JNK. Rho-kinase, which has been used for the clinical treatment of cerebral vasospasms, may be involved in other central nervous system (CNS) disorders such as traumatic injury, stroke, neurodegenerative disease and neuropathic pain. TNF-alpha, a proinflammatory cytokine that affects the CNS through cytokines, such as IL-6, release from neurons, astrocytes and microglia. Therefore, we investigated the involvement of Rho-kinase in the TNF-alpha-induced IL-6 release from rat C6 glioma cells. These results strongly suggest that Rho-kinase regulates the TNF-alpha-induced IL-6 release at a point upstream from p38 MAPK and SAPK/JNK in C6 glioma cells. Therefore, Rho-kinase inhibitor may be considered to be a new clinical candidate for the treatment of CNS disorders in addition to cerebral vasospasms.

Targeting cerebrovascular Rho-kinase in stroke

BACKGROUND

Rho and Rho-associated kinase (ROCK) play pivotal roles in pathogenesis of vascular diseases including stroke. ROCK is expressed in all cell types relevant to stroke, and regulates a range of physiological processes.

OBJECTIVE

To provide an overview of ROCK as an experimental therapeutic target in cerebral ischemia, and the translational opportunities and obstacles in the prophylaxis and treatment of stroke.

METHODS

Relevant literature was reviewed.

RESULTS

ROCK activity is upregulated in chronic vascular risk factors such as diabetes, hyperlipidemia and hypertension, and more acutely by cerebral ischemia. ROCK activation is predicted to increase the risk of cerebral ischemia, and worsen the ischemic tissue outcome and functional recovery. Evidence suggests that ROCK inhibition is protective in models of cerebral ischemia. The benefit is mediated through multiple mechanisms.

CONCLUSION

ROCK is a promising therapeutic target in all stages of stroke.

Biomaterials for the central nervous system

Biomaterials are widely used to help treat neurological disorders and/or improve functional recovery in the central nervous system (CNS). This article reviews the application of biomaterials in (i) shunting systems for hydrocephalus, (ii) cortical neural prosthetics, (iii) drug delivery in the CNS, (iv) hydrogel scaffolds for CNS repair, and (v) neural stem cell encapsulation for neurotrauma. The biological and material requirements for the biomaterials in these applications are discussed. The difficulties that the biomaterials might face in each application and the possible solutions are also reviewed in this article.

A novel transport and delivery mechanism underpins the effectiveness of prolyl-m-sarcolysyl-p-fluorophenylalanine (PSF) in a human melanoma xenograft nude-mouse model

The alkylating peptide PSF shows very promising results in vitro on different cancer cells but its efficacy in animals has not been assessed. Here we evaluate the efficacy of PSF in human melanoma-bearing nude mice and examine the underlying mechanism. In melanoma-bearing nude mice, escalating doses of PSF showed dose-dependent responses and reached tumor regression with an optimal dose of 20 mg/kg for 1 month. A comparison of PSF with its free moiety m-sarcolysin and melphalan showed a highly significant advantage of PSF. Furthermore, dose fractionation yielded an even better control of tumor regrowth. In vitro studies unraveled an original delivery mechanism based on the rapid binding of PSF mainly due to red blood cells to form a pro-drug complex and the subsequent release of active metabolites by tumor-associated proteolytic enzymes. Blood kinetics showed one major metabolite partially released over time, while in the presence of melanoma cells three additional metabolites are generated. Interestingly, tumor-shed proteases also induce the production of these metabolites and varying combinations of enzyme inhibitors indicate the involvement of metallo- and other families of proteases in the delivery process. This particular transport and delivery of such an alkylating agent may have several benefits, mainly lowering the drug-free moiety in plasma and at the same time increasing its concentration in protease rich areas such as tumors.

Intra-arterial drug delivery: a concise review

The therapeutic potential of intra-arterial (IA) drug delivery to the brain has received limited attention in the last decade. In the 1980s, efforts to treat brain tumors with IA chemotherapy, the leading application of this technology, yielded modest results. Poor control of tissue drug concentrations and the potential risk of permanent neurologic injury further prevented the wider use of IA drugs. Yet, IA drugs were anecdotally used for treating a wide spectrum of brain diseases. Recent advances in endovascular technology and the increased safety of angiographic procedures now compel us to reevaluate IA drug delivery. This review describes the pharmacologic principles, applications, and pitfalls of IA drug delivery to the brain.

Crucial role of Rho-nuclear factor-kappaB axis in angiotensin II-induced renal injury

This study was performed to determine the effectiveness of the Rho kinase inhibitor and NF-kappaB inhibitor in renal injury of ANG II-infused hypertensive rats. Male Sprague-Dawley rats, maintained on a normal diet, received either a sham operation (n = 7) or continuous ANG II infusion (120 ng/min) subcutaneously via minipumps. The ANG II-infused rats were further subdivided into three subgroups (n = 7 each) to receive one of the following treatments during the entire period: vehicle, Rho kinase inhibitor (fasudil; 3 mg.kg(-1).day(-1) ip), or NF-kappaB inhibitor (parthenolide; 1 mg.kg(-1).day(-1) ip). After 12 days of ANG II infusion, systolic blood pressure (BP; 208 +/- 7 vs. 136 +/- 3 mmHg), Rho kinase activity, NF-kappaB activity, renal ANG II contents (160 +/- 25 vs. 84 +/- 14 pg/g), monocytic chemotactic protein (MCP) 1 mRNA, interstitial macrophage infiltration, transforming growth factor-beta1 (TGF-beta1) mRNA, interstitial collagen-positive area, urinary protein excretion (43 +/- 6 vs. 11 +/- 2 mg/day), and urinary albumin excretion were significantly enhanced compared with the Sham group. While fasudil or parthenolide did not alter systolic BP (222 +/- and 190 +/- 21, respectively), both treatments completely blocked ANG II-induced enhancement of NF-kappaB activity, renal ANG II contents (103 +/- 11 and 116 +/- 21 pg/g, respectively), MCP1 mRNA, interstitial macrophage infiltration, TGF-beta1 mRNA, interstitial collagen-positive area, urinary protein excretion (28 +/- 6 and 23 +/- 3 mg/day, respectively), and urinary albumin excretion. Importantly, parthenolide did not alter ANG II-induced Rho kinase activation although fasudil abolished ANG II-induced Rho kinase activation. These data indicate that the Rho-NF-kappaB axis plays crucial roles in the development of ANG II-induced renal injury independently from BP regulation.