Springer Science and Business Media LLC

The prognosis for glioma patients is poor, and development of new treatments is critical. Previously, we engineered polymer-based vaccines that control GM-CSF, CpG-oligonucleotide, and tumor-lysate presentation to regulate immune cell trafficking and activation, which promoted potent immune responses against peripheral tumors. Here, we extend the use of this system to glioma. Rats were challenged with an intracranial injection of glioma cells followed (1 week) by administration of the polymeric vaccine (containing GM-CSF, CpG, and tumor-lysate) in the tumor bed. Control rats were treated with blank matrices, matrices with GM-CSF and CpG, or intra-tumoral bolus injections of GM-CSF, CpG, and tumor lysate. Rats were monitored for survival and tested for neurological function. Survival studies confirmed a benefit of the polymeric vaccine as 90% of vaccinated rats survived for >100 days. Control rats exhibited minimal benefit. Motor tests revealed that vaccination protected against the loss of forelimb use produced by glioma growth. Histological analysis quantitatively confirmed a robust and rapid reduction in tumor size. Long-term immunity was confirmed when 67% of survivors also survived a second glioma challenge. These studies extend previous reports regarding this approach to tumor therapy and justify further development for glioma treatment.

Endothelial cells play critical roles in circulatory homeostasis and are also the gateway to the major organs of the body. Dysfunction, injury, and gene expression profiles of these cells can cause, or are caused by, prevalent chronic diseases such as diabetes, cardiovascular disease, and cancer. Modulation of gene expression within endothelial cells could therefore be therapeutically strategic in treating longstanding disease challenges. Lipid nanoparticles (LNP) have emerged as potent, scalable, and tunable carrier systems for delivering nucleic acids, making them attractive vehicles for gene delivery to endothelial cells. Here, we discuss the functions of endothelial cells and highlight some receptors that are upregulated during health and disease. Examples and applications of DNA, mRNA, circRNA, saRNA, siRNA, shRNA, miRNA, and ASO delivery to endothelial cells and their targets are reviewed, as well as LNP composition and morphology, formulation strategies, target proteins, and biomechanical factors that modulate endothelial cell targeting. Finally, we discuss FDA-approved LNPs as well as LNPs that have been tested in clinical trials and their challenges, and provide some perspectives as to how to surmount those challenges.

To modify blood-contacting stainless surfaces by covalently coating them with a serum-protease resistant form of tropoelastin (TE). To demonstrate that the modified TE retains an exposed, cell-adhesive C-terminus that persists in the presence of blood plasma proteases. Recombinant human TE and a point mutant variant (R515A) of TE were labeled with 125Iodine and immobilized on plasma-activated stainless steel (PAC) surfaces. Covalent attachment was confirmed using rigorous detergent washing. As kallikrein and thrombin dominate the serum degradation of tropoelastin, supraphysiological levels of these proteases were incubated with covalently bound TE and R515A, then assayed for protein levels by radioactivity detection. Persistence of the C-terminus was assessed by ELISA. TE was significantly retained covalently on PAC surfaces at 88 ± 5% and 71 ± 5% after treatment with kallikrein and thrombin, respectively. Retention of R515A was 100 ± 1.3% and 87 ± 2.3% after treatment with kallikrein and thrombin, respectively, representing significant improvements over TE. The functionally important C-terminus was cleaved in wild-type TE but retained by R515A. Protein persists in the presence of human kallikrein and thrombin when covalently immobilized on metal substrata. R515A displays enhanced protease resistance and retains the C-terminus presenting a protein interface that is viable for blood-contacting applications.

To develop an aerosol system for efficient local lung delivery of a tuberculostatic drug. The antibiotic, capreomycin sulfate, was spray dried to form a dry powder aerosol. The chemical content and physical properties of resulting particles were assessed under various storage conditions. Plasma concentrations of capreomycin after insufflation into guinea pigs were evaluated at three doses, and compared to IV and IM administration of a capreomycin solution. Dry powder aerosols containing capreomycin were formulated to enable efficient delivery of large drug masses to the lungs of guinea pigs. Aerosols loaded with 73% CS were shown to possess good aerosolization properties and physical–chemical stability for up to 3 months at room temperature. Upon insufflation into guinea pigs, the amount of CS reaching the bloodstream was significantly lower compared to IV or IM administration, but resulted in a significantly longer drug half-life. The results indicate that large doses of capreomycin in dry powder form can be efficiently delivered to the lungs of guinea pigs, which may result in high local drug exposure but significantly reduced systemic exposure as suggested by plasma concentrations in the present studies. These systems have considerable potential to provide more effective therapy for MDR-TB

To evaluate vinorelbine drug exposure and activity in brain metastases of the human MDA-MB-231BR breast cancer model using integrated imaging and analysis. Brain and systemic metastases were created by administration of cancer cells in female NuNu mice. After metastases developed, animals were administered vinorelbine at the maximal tolerated dose (12 mg/kg), and were evaluated thereafter for total and unbound drug pharmacokinetics, biomarker TUNEL staining, and barrier permeability to Texas red. Median brain metastasis drug exposure was 4-fold greater than normal brain, yet only ~8% of non-barrier systemic metastases, which suggests restricted brain exposure. Unbound vinorelbine tissue/plasma partition coefficient, Kp,uu, equaled ~1.0 in systemic metastases, but 0.03–0.22 in brain metastases, documenting restricted equilibration. In select sub-regions of highest drug-uptake brain metastases, Kp,uu approached 1.0, indicating complete focal barrier breakdown. Most vinorelbine-treated brain metastases exhibited little or no positive early apoptosis TUNEL staining in vivo. The in vivo unbound vinorelbine IC50 for TUNEL-positive staining (56 nM) was 4-fold higher than that measured in vitro (14 nM). Consistent with this finding, P-glycoprotein expression was observed to be substantially upregulated in brain metastasis cells in vivo. Vinorelbine exposure at maximum tolerated dose was less than one-tenth that in systemic metastases in >70% of brain metastases, and was associated with negligible biomarker effect. In small subregions of the highest uptake brain metastases, compromise of blood-tumor barrier appeared complete. The results suggest that restricted delivery accounts for 80% of the compromise in drug efficacy for vinorelbine against this model.

To control degradation and protein release using thermo-responsive hydrogels for localized delivery of anti-angiogenic proteins. Thermo-responsive hydrogels derived from N-isopropylacrylamide (NIPAAm) and crosslinked with poly(ethylene glycol)-co-(L-lactic acid) diacrylate (Acry-PLLA-b-PEG-b-PLLA-Acry) were synthesized via free radical polymerization in the presence of glutathione, a chain transfer agent (CTA) added to modulate their degradation and release properties. Immunoglobulin G (IgG) and the recombinant proteins Avastin® and Lucentis® were encapsulated in these hydrogels and their release was studied. The encapsulation efficiency of IgG was high (75–87%) and decreased with CTA concentration. The transition temperature of these hydrogels was below physiological temperature, which is important for minimally invasive therapies involving these materials. The toxicity from unreacted monomers and free radical initiators was eliminated with a minimum of three buffer extractions. Addition of CTA accelerated degradation and resulted in complete protein release. Glutathione caused the degradation products to become solubilized even at 37°C. Hydrogels prepared without glutathione did not disintegrate nor released protein completely after 3 weeks at 37°C. PEGylation of IgG postponed the burst release effect. Avastin® and Lucentis® released from degraded hydrogels retained their biological activity. These systems offer a promising platform for the localized delivery of proteins.