Sustained-Release Microspheres of Rivoceranib for the Treatment of Subfoveal Choroidal Neovascularization.

The wet type of age-related macular degeneration (AMD) accompanies the subfoveal choroidal neovascularization (CNV) caused by the abnormal extension or remodeling of blood vessels to the macula and retinal pigment epithelium (RPE). Vascular endothelial growth factor (VEGF) is known to play a crucial role in the pathogenesis of the disease. In this study, we tried to repurpose an investigational anticancer drug, rivoceranib, which is a selective inhibitor of VEGF receptor-2 (VEGFR2), and evaluate the therapeutic potential of the drug for the treatment of wet-type AMD in a laser-induced CNV mouse model using microsphere-based sustained drug release formulations. The PLGA-based rivoceranib microsphere can carry out a sustained delivery of rivoceranib for 50 days. When administered intravitreally, the sustained microsphere formulation of rivoceranib effectively inhibited the formation of subfoveal neovascular lesions in mice.

Effective systemic siRNA delivery using dual-layer protected long-circulating nanohydrogel containing an inorganic core.

Systemic delivery of small interfering RNA (siRNA) has been mainly impeded by enzymatic degradation and poor cellular uptake. Calcium phosphate (CaP) has been considered a potential candidate for siRNA delivery because of its excellent biocompatibility and capability of entrapping siRNA in the crystal core. Based on the property of 3,4-dihydroxy-l-phenylalanine (dopa) binding to the surface of the CaP crystal, dual hydrogel layers consisting of a macromolecular dextran (dex) and polyethylene glycol (PEG) were introduced on the surface of the inorganic CaP core for prolonged circulation. Dextran conjugated with dopa and polyethylene glycol (PEG) (PEG-dex-dopa) can effectively control the overgrowth of the CaP/siRNA core and stabilize it by dual electrically neutral hydrophilic layers of dextran and PEG, which additionally provide reduced hepatic accumulation and systemic clearance. The dual shield of PEG-dex-dopa nanohydrogel containing a CaP/siRNA core (PEG-dex-dopa/CaP/siRNA) significantly improved the pharmacokinetic behaviors of siRNA after systemic administration, resulting in its increased distribution to tumors and the effective inhibition of tumor growth by silencing vascular endothelial growth factor (VEGF) gene expression through the enhanced permeability and retention (EPR) effect.

Enhanced Transfection of Human Mesenchymal Stem Cells Using a Hyaluronic Acid/Calcium Phosphate Hybrid Gene Delivery System.

Human mesenchymal stem cells (hMSCs) show enormous potential in regenerative medicine and tissue engineering. However, current use of hMSCs in clinics is still limited because there is no appropriate way to control their behavior in vivo, such as differentiation to a desired cell type. Genetic modification may provide an opportunity to control the cells in an active manner. One of the major hurdles for genetic manipulation of hMSCs is the lack of an efficient and safe gene delivery system. Herein, biocompatible calcium phosphate (CaP)-based nanoparticles stabilized with a catechol-derivatized hyaluronic acid (dopa-HA) conjugate were used as a carrier for gene transfection to hMSCs for improved differentiation. Owing to the specific interactions between HA and CD44 of bone marrow-derived hMSCs, dopa-HA/CaP showed significantly higher transfection in hMSCs than branched polyethylenimine (bPEI, MW 25 kDa) with no cytotoxicity. The co-delivery of a plasmid DNA encoding bone morphogenetic protein 2 (BMP-2 pDNA) and micro RNA 148b (miRNA-148b) by dopa-HA/CaP achieved significantly improved osteogenic differentiation of hMSCs.

Early Experiences Using Cocoon Occluders for Closure of a Ventricular Septal Defect.

BACKGROUND: Transcatheter device closure of ventricular septal defect (VSD) has become an attractive alternative to surgery. We report here on our early experiences of transcatheter closure of VSD using Cocoon devices, which are now available in Korea. METHODS: We reviewed the medical records and angiographic images of 13 patients who underwent transcatheter closure of VSD with a Cocoon occluder at Samsung Medical Center. The median patient age was 5.8 years, and the median patient weight was 20.3 kg. RESULTS: The device was successfully implanted in all patients. The follow-up period was 10 ± 6 months, and no mortality was observed. An immediate residual leak on the next day was detected in 7 patients (including 4 with perimembranous VSD). However, 6 months later, a residual leak was observed only in 2 patients with perimembranous VSD and 1 patient with muscular VSD. Early conduction abnormalities were observed in 3 patients, all of whom had perimembranous VSD, but no significant complete atrioventricular block was observed. One patient experienced newly developed significant aortic regurgitation that decreased spontaneously but still existed at the 6 month follow-up. No hemolysis or embolization was noted on the next day or during the follow-up period. CONCLUSIONS: Cocoon devices can be used safely and effectively for VSD closure. However, residual leaks and conduction abnormalities may occur early after implantation, especially in patients with perimembranous VSD. Although normal conduction was recovered, long-term evaluation remains essential.

Enhanced Cancer Vaccination by In Situ Nanomicelle-Generating Dissolving Microneedles.

Efficient delivery of tumor antigens and immunostimulatory adjuvants into lymph nodes is crucial for the maturation and activation of antigen-presenting cells (APCs), which subsequently induce adaptive antitumor immunity. A dissolving microneedle (MN) has been considered as an attractive method for transcutaneous immunization due to its superior ability to deliver vaccines through the stratum corneum in a minimally invasive manner. However, because dissolving MNs are mostly prepared using water-soluble sugars or polymers for their rapid dissolution in intradermal fluid after administration, they are often difficult to formulate with poorly water-soluble vaccine components. Here, we develop amphiphilic triblock copolymer-based dissolving MNs in situ that generate nanomicelles (NMCs) upon their dissolution after cutaneous application, which facilitate the efficient encapsulation of poorly water-soluble Toll-like receptor 7/8 agonist (R848) and the delivery of hydrophilic antigens. The sizes of NMCs range from 30 to 40 nm, which is suitable for the efficient delivery of R848 and antigens to lymph nodes and promotion of cellular uptake by APCs, minimizing systemic exposure of the R848. Application of MNs containing tumor model antigen (OVA) and R848 to the skin of EG7-OVA tumor-bearing mice induced a significant level of antigen-specific humoral and cellular immunity, resulting in significant antitumor activity.

Erratum: Early Experiences Using Cocoon Occluders for Closure of a Ventricular Septal Defect.

[This corrects the article on p. 165 in vol. 26, PMID: 30310884.].

Inhibition of Tumor Growth via Systemic siRNA Delivery Using Reducible Bile Acid-Conjugated Polyethylenimine.

RNA interference (RNAi), mediated by small interfering RNA (siRNA), has been considered as a potential therapeutic agent for cancer owing to its ability to suppress target genes in a sequence-specific manner. In this study, a conjugate of the low molecular weight (MW) polyethylenimine (PEI) (MW 1800) and deoxycholic acid (DA) was further modified with 4-fluorothiophenol (FTP) (TP-DA-PEI) to achieve systemic siRNA delivery. The thiophenol group would be involved with disulfide bonds between the polymer chains and siRNA modified with free thiols (thiol-siRNA) to form and π⁻π interactions between the pendent aromatic groups and coprostane ring of the bile acid. The TP-DA-PEI conjugates could generate stable nanoparticles with thiol-siRNA. The TP-DA-PEI conjugate not only achieved enhanced intracellular uptake, serum stability, and transfection efficiency, but also showed high accumulation of TP-DA-PEI/thiol-siRNA polyplexes and significant tumor growth inhibition effect in tumor-bearing mice after systemic administration.