Single injection of ONO-1301-loaded PLGA microspheres directly after ischaemia reduces ischaemic damage in rats subjected to middle cerebral artery occlusion

New regional drug delivery system by direct epicardial placement of slow-release prostacyclin agonist promise therapeutic angiogenesis in a porcine chronic myocardial infarction

Although prostacyclin is an endogenous factor for the protection and regeneration of damaged tissue, the use of clinically available prostacyclin analogues for treating chronic pathological conditions is limited owing to their short half-lives. A new reagent, ONO-1301SR, which is a unique synthetic prostacyclin agonist polymerized with lactic and glycolic acid, has been demonstrated to constitutively release prostacyclin analogues to adjacent tissues, suggesting its therapeutic potential via slow-release delivery into a specific organ. In this study, we investigated the regenerative effect of direct epicardial delivery of the ONO-1301SR on a heart with a chronic myocardial infarct. An ameroid constrictor was placed on the left anterior descending coronary artery of Göttingen minipigs for 4 weeks to induce ischemic cardiomyopathy; this was followed by direct epicardial placement of ONO-1301SR-immersed gelatinous sheet, or only a gelatinous sheet on the anterolateral surface of the heart. Epicardial placement of ONO-1301SR resulted in significant recovery of global cardiac functions and regional wall motion of the lateral wall. Importantly, after epicardial placement of ONO-1301SR for 4 weeks, the myocardial blood flow significantly increased in the lateral region as assessed by ¹³N-ammonia positron emission tomography; this finding was consistent with significantly increased capillary density in the peri-infarct area with up-regulated angiogenic cytokine expression. Conclusion: Use of the slow-release drug delivery system of prostacyclin agonist yielded regenerative angiogenesis, including increased regional blood perfusion and systolic function in a porcine model of chronic myocardial infarction.

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.

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.

Single injection of sustained-release prostacyclin analog ONO-1301-MS ameliorates hypoxic toxicity in the murine model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by several pathologies including oxidative stress, apoptosis, neuroinflammation, and glutamate toxicity. Although multiple reports suggest that ischemia and hypoxia in the spinal cord plays a pivotal role in the pathogenesis of ALS, the precise role of hypoxia in disease progression remains unknown. In this study, we detected higher expression levels of Hypoxia-inducible factor 1-alpha (HIF-1α), a key regulator of cellular responses to hypoxia, in the spinal cord of ALS patients and in the transgenic mice overexpressing the familial ALS-associated G93A SOD1 mutation (mSOD1^G93A mice) compared to controls. Single subcutaneous administration of sustained-release prostacyclin analog ONO-1301-MS to mSOD1^G93A mice abrogated the expression of HIF-1α in their spinal cords, as well as erythropoietin (EPO) and vascular endothelial growth factor (VEGF), both of which are downstream to HIF-1α. Furthermore, ONO-1301-MS increased the level of mature brain-derived neurotrophic factor (BDNF) and ATP production in the spinal cords of mSOD1^G93A mice. At late disease stages, the motor function and the survival of motor neurons of ONO-1301-MS-treated mSOD1^G93A mice was significantly improved compared to vehicle-treated mSOD1^G93A mice. Our data suggest that vasodilator therapy modulating local blood flow in the spinal cord has beneficial effects against ALS disease progression.

Time-course investigation of blood-brain barrier permeability and tight junction protein changes in a rat model of permanent focal ischemia

Permanent middle cerebral artery occlusion (pMCAO) is an animal model that is widely used to simulate human ischemic stroke. However, the timing of the changes in the expression of tight junction (TJ) proteins and synaptic proteins associated with pMCAO remain incompletely understood. Therefore, to further explore the characteristics and mechanisms of blood-brain barrier (BBB) damage during cerebral ischemic stroke, we used a pMCAO rat model to define dynamic changes in BBB permeability within 120 h after ischemia in order to examine the expression levels of the TJ proteins claudin-5 and occludin and the synaptic proteins synaptophysin (SYP) and postsynaptic density protein 95 (PSD95). In our study, Evans blue content began to increase at 4 h and was highest at 8 and 120 h after ischemia. TTC staining showed that cerebral infarction was observed at 4 h and that the percentage of infarct volume increased with time after ischemia. The expression levels of claudin-5 and occludin began to decline at 1 h and were lowest at 8 and 120 h after ischemia. The expression levels of SYP and PSD95 decreased from 12 to 120 h after ischemia. GFAP, an astrocyte marker, gradually increased in the cortex penumbra over time post-ischemia. Our study helps clarify the characteristics of pMCAO models and provides evidence supporting the translational potential of animal stroke models.

Biomaterial Applications in Cell-Based Therapy in Experimental Stroke

Stroke is an important health issue corresponding to the second cause of mortality and first cause of severe disability with no effective treatments after the first hours of onset. Regenerative approaches such as cell therapy provide an increase in endogenous brain structural plasticity but they are not enough to promote a complete recovery. Tissue engineering has recently aroused a major interesting development of biomaterials for use into the central nervous system. Many biomaterials have been engineered based on natural compounds, synthetic compounds, or a mix of both with the aim of providing polymers with specific properties. The mechanical properties of biomaterials can be exquisitely regulated forming polymers with different stiffness, modifiable physical state that polymerizes in situ, or small particles encapsulating cells or growth factors. The choice of biomaterial compounds should be adapted for the different applications, structure target, and delay of administration. Biocompatibilities with embedded cells and with the host tissue and biodegradation rate must be considerate. In this paper, we review the different applications of biomaterials combined with cell therapy in ischemic stroke and we explore specific features such as choice of biomaterial compounds and physical and mechanical properties concerning the recent studies in experimental stroke.

A sustained-release drug-delivery system of synthetic prostacyclin agonist, ONO-1301SR: a new reagent to enhance cardiac tissue salvage and/or regeneration in the damaged heart

Cardiac failure is a major cause of mortality and morbidity worldwide, since the standard treatment for cardiac failure in the clinical practice is chiefly to focus on removal of insults against the heart or minimisation of additional factors to exacerbate cardiac failure, but not on regeneration of the damaged cardiac tissue. A synthetic prostacyclin agonist, ONO-1301, has been developed as a long-acting drug for acute and chronic pathologies related to regional ischaemia, inflammation and/or interstitial fibrosis by pre-clinical studies. In addition, poly-lactic co-glycolic acid-polymerised form of ONO-1301, ONO-1301SR, was generated to achieve a further sustained release of this drug into the targeted region. This unique reagent has been shown to act on fibroblasts, vascular smooth muscle cells and endothelial cells in the tissue via the prostaglandin IP receptor to exert paracrinal release of multiple protective factors, such as hepatocyte growth factor, vascular endothelial growth factor or stromal cell-derived factor-1, into the adjacent damaged tissue, which is salvaged and/or regenerated as a result. Our laboratory developed a new surgical approach to treat acute and chronic cardiac failure using a variety of animal models, in which ONO-1301SR is directly placed over the cardiac surface to maximise the therapeutic effects and minimise the systemic complications. This review summarises basic and pre-clinical information of ONO-1301 and ONO-1301SR as a new reagent to enhance tissue salvage and/or regeneration, with a particular focus on the therapeutic effects on acute and chronic cardiac failure and underlying mechanisms, to explore a potential in launching the clinical study.

A sustained prostacyclin analog, ONO-1301, attenuates pancreatic fibrosis in experimental chronic pancreatitis induced by dibutyltin dichloride in rats

BACKGROUND

ONO-1301, a novel sustained-release prostacyclin agonist, has an anti-fibrotic effect on the lungs, heart, and kidneys that is partly associated with the induction of hepatocyte growth factor (HGF). This study examined the anti-fibrotic effect of ONO-1301 on chronic pancreatitis (CP) progression.

METHODS

CP was induced in rats in vivo by dibutyltin dichloride (DBTC). Seven days after DBTC injection (day 7), a slow-release form of ONO-1301 (10 mg/kg; ONO-1301-treated group) or vehicle (DBTC-treated group) was injected. On days 14 and 28, we evaluated the histopathological CP score and mRNA expressions of HGF, cytokines, and collagen in the pancreas by real-time RT-PCR. In vitro, monocytes and pancreatic stellate cells (PSCs) were isolated from normal rat spleen and pancreas, respectively. The cytokine and collagen expressions of monocytes and PSCs were detected by real-time RT-PCR, and PSCs proliferation was examined by BrdU assay.

RESULTS

Histopathological CP scores in vivo improved in the ONO-1301-treated group compared to the DBTC-treated group, particularly inflammatory cell infiltration on day 14 and interstitial fibrosis on day 28. HGF mRNA increased significantly after ONO-1301 administration, whereas IL-1β, TNF-α, TGF-β, MCP-1, and collagen mRNA decreased significantly. Cytokine expression in monocytes was suppressed in vitro not only by HGF, but also ONO-1301 alone. However, neither ONO-1301 nor HGF affected the proliferation, or cytokine or collagen expression of PSCs.

CONCLUSIONS

ONO-1301 suppresses pancreatic fibrosis in the DBTC-induced CP model by inhibiting monocyte activity not only with induction of HGF but also by ONO-1301 itself.

Elevated prostacyclin biosynthesis in mice impacts memory and anxiety-like behavior

Prostacyclin is an endogenous lipid metabolite with properties of vasodilation and anti-platelet aggregation. While the effects of prostacyclin on the vascular protection have been well-documented, the role of this eicosanoid in the central nervous system has not been extensively studied. Recently, a transgenic mouse containing a hybrid enzyme, of cyclooxygenase-1 linked to prostacyclin synthase, was developed that produces elevated levels of prostacyclin in vivo. The goal of this study was to investigate whether increased prostacyclin biosynthesis could affect behavioral phenotypes in mice. Our results uncovered that elevated levels of prostacyclin broadly affect both cognitive and non-cognitive behaviors, including decreased anxiety-like behavior and improved learning in the fear-conditioning memory test. This study demonstrates that prostacyclin plays an important, but previously unrecognized, role in central nervous system function and behavior.

Novel long-acting prostacyclin agonist (ONO-1301) with an angiogenic effect: promoting synthesis of hepatocyte growth factor and increasing cyclic AMP concentration via IP-receptor signaling

The purpose of this study was to evaluate the angiogenic potency of ONO-1301, a novel prostacyclin agonist, using a murine sponge model. Solutions of ONO-1301 or hepatocyte growth factor (HGF), as a positive control, were injected into sponges in the backs of mice, daily for 14 days. Hemoglobin and HGF levels in the sponge were increased for up to 14 days on daily treatment with ONO-1301 while on HGF treatment, they peaked on day 7 and had decreased again by day 14. ONO-1301 also upregulated c-Met expression for 14 days in a dose-dependent manner. When the mice were pretreated with an antibody to HGF or the prostaglandin I (IP)-receptor antagonist CAY10441, the angiogenic effect of ONO-1301 was dramatically reduced. Plasma concentrations of cyclic adenosine monophosphate (cAMP) were increased in a dose-dependent manner by once daily treatment with ONO-1301 for 14 days. This effect was reduced by pretreatment with the IP-receptor antagonist. In conclusion, hemoglobin level was increased by repeated treatment with ONO-1301 for 14 days. It is suggested that ONO-1301 induced angiogenesis by promoting the synthesis of HGF and upregulated c-Met expression, followed by an increase in cAMP concentrations mediated by IP-receptor signaling.

A nanoparticle depot formulation of 4-(N)-stearoyl gemcitabine shows a strong anti-tumour activity

OBJECTIVES

Depot formulation as a carrier for cytotoxic chemotherapeutic drugs is not well studied. The objective of this study is to test the feasibility of using a subcutaneous depot formulation to administer a cytotoxic anti-cancer drug for systemic therapy.

METHODS

A fatty-acid amide prodrug of the nucleoside analogue gemcitabine (4-(N)-stearoyl gemcitabine (GemC18)) was incorporated into poly(lactic-co-glycolic acid) (PLGA) nanoparticles or microspheres. A GemC18 solution was used as a control. The anti-tumour activity was evaluated after subcutaneous injection of the different formulations in C57BL/6 mice with pre-established model tumours. The clearance of GemC18 from the injection site was determined by measuring the percentage of GemC18 remaining at the injection site at different times after the injection.

KEY FINDINGS

The depot formulation based on the GemC18-loaded PLGA nanoparticles showed the strongest anti-tumour effect, likely due to the proper 'release' of GemC18 from the injection site.

CONCLUSIONS

It is feasible to dose cytotoxic anti-cancer drugs as a nanoparticle-based depot formulation, especially when combined with an advanced prodrug strategy.