Near infrared triggered chemo-PTT-PDT effect mediated by glioma directed twin functional-chimeric peptide-decorated gold nanoroses.

The successful application of nanomedicine against glioma is basically hooked on to the fabrication of specific and efficient glioma targeted multifunctional theranostics. Herein, through an easy synthetic methodology, we fabricated a type of novel multifunctional theranostic nanoplatform comprising of anisotropic gold nanoroses (AuNs) co-loaded with doxorubicin (DOX) and the near-infrared (NIR) active/responsive dye, indocyanine green (ICG). The tailored nanotheranostics upon being exposed to NIR laser helped in achieving combinatorial chemo-phototherapy along with optical cell imaging. BBB/glioma-targeting ability was realized by amalgamating the AuNs with a naive peptide drug with BBB-glioma targeting and anti-glioma twin functionality. Efficacy studies carried out in C6 cells and spheroids demonstrated heightened synergistic glioma chemo-PDT-PTT effect (~85% ablation in C6 cells and ~88% in C6 spheroids) by the AuNDIPs as compared to the individual therapeutic entities. Here, the AuNs derived nanophototheranostics with in force targeting and on-demand drug release nature will further aid in abolishing chemotherapy associated adverse events by adopting a combinatorial approach for synergistic glioma eradication.

Oxidative Stress Induces a Breakdown of the Cytoskeleton and Tight Junctions of the Corneal Endothelial Cells.

Purpose: To investigate the impact of oxidative stress, which is a hallmark of Fuchs dystrophy, on the barrier function of the corneal endothelial cells. Methods: Experiments were carried out with cultured bovine and porcine corneal endothelial cells. For oxidative stress, cells were supplemented with riboflavin (Rf) and exposed to UV-A (15-30 min) to induce Type-1 photochemical reactions that release H2O2. The effect of the stress on the barrier function was assayed by transendothelial electrical resistance (TER) measurement. In addition, the associated changes in the organization of the microtubules, perijunctional actomyosin ring (PAMR), and ZO-1 were evaluated by immunocytochemistry, which was also repeated after direct exposure to H2O2 (100 µM, 1 h). Results: Exposure to H2O2 led to the disassembly of microtubules and the destruction of PAMR. In parallel, the contiguous locus of ZO-1 was disrupted, marking a loss of barrier integrity. Accordingly, a sustained loss in TER was induced when cells in the Rf-supplemented medium were exposed to UV-A. However, the addition of catalase (7,000 U/mL) to rapidly decompose H2O2 limited the loss in TER. Furthermore, the adverse effects on microtubules, PAMR, and ZO-1 were suppressed by including catalase, ascorbic acid (1 mM; 30 min), or pretreatment with p38 MAP kinase inhibitor (SB-203580; 10 µM, 1 h). Conclusions: Acute oxidative stress induces microtubule disassembly by a p38 MAP kinase-dependent mechanism, leading to the destruction of PAMR and loss of barrier function. The response to oxidative stress is reminiscent of the (TNF-α)-induced breakdown of barrier failure in the corneal endothelium.

Silibinin, dexamethasone, and doxycycline as potential therapeutic agents for treating vesicant-inflicted ocular injuries.

There are no effective and approved therapies against devastating ocular injuries caused by vesicating chemical agents sulfur mustard (SM) and nitrogen mustard (NM). Herein, studies were carried out in rabbit corneal cultures to establish relevant ocular injury biomarkers with NM for screening potential efficacious agents in laboratory settings. NM (100nmol) exposure of the corneas for 2h (cultured for 24h), showed increases in epithelial thickness, ulceration, apoptotic cell death, epithelial detachment microbullae formation, and the levels of VEGF, cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9). Employing these biomarkers, efficacy studies were performed with agent treatments 2h and every 4h thereafter, for 24h following NM exposure. Three agents were evaluated, including prescription drugs dexamethasone (0.1%; anti-inflammatory steroid) and doxycycline (100nmol; antibiotic and MMP inhibitor) that have been studied earlier for treating vesicant-induced eye injuries. We also examined silibinin (100µg), a non-toxic natural flavanone found to be effective in treating SM analog-induced skin injuries in our earlier studies. Treatments of doxycycline+dexamethasone, and silibinin were more effective than doxycycline or dexamethasone alone in reversing NM-induced epithelial thickening, microbullae formation, apoptotic cell death, and MMP-9 elevation. However, dexamethasone and silibinin alone were more effective in reversing NM-induced VEGF levels. Doxycycline, dexamethasone and silibinin were all effective in reversing NM-induced COX-2 levels. Apart from therapeutic efficacy of doxycycline and dexamethasone, these results show strong multifunctional efficacy of silibinin in reversing NM-induced ocular injuries, which could help develop effective and safe therapeutics against ocular injuries by vesicants.

Rescue of photoreceptor degeneration by curcumin in transgenic rats with P23H rhodopsin mutation.

The P23H mutation in the rhodopsin gene causes rhodopsin misfolding, altered trafficking and formation of insoluble aggregates leading to photoreceptor degeneration and autosomal dominant retinitis pigmentosa (RP). There are no effective therapies to treat this condition. Compounds that enhance dissociation of protein aggregates may be of value in developing new treatments for such diseases. Anti-protein aggregating activity of curcumin has been reported earlier. In this study we present that treatment of COS-7 cells expressing mutant rhodopsin with curcumin results in dissociation of mutant protein aggregates and decreases endoplasmic reticulum stress. Furthermore we demonstrate that administration of curcumin to P23H-rhodopsin transgenic rats improves retinal morphology, physiology, gene expression and localization of rhodopsin. Our findings indicate that supplementation of curcumin improves retinal structure and function in P23H-rhodopsin transgenic rats. This data also suggest that curcumin may serve as a potential therapeutic agent in treating RP due to the P23H rhodopsin mutation and perhaps other degenerative diseases caused by protein trafficking defects.

Brain mitochondrial drug delivery: influence of drug physicochemical properties.

PURPOSE: To determine the influence of drug physicochemical properties on brain mitochondrial delivery of 20 drugs at physiological pH. METHODS: The delivery of 8 cationic drugs (beta-blockers), 6 neutral drugs (corticosteroids), and 6 anionic drugs (non-steroidal anti-inflammatory drugs, NSAIDs) to isolated rat brain mitochondria was determined with and without membrane depolarization. Multiple linear regression was used to determine whether lipophilicity (Log D), charge, polarizability, polar surface area (PSA), and molecular weight influence mitochondrial delivery. RESULTS: The Log D for beta-blockers, corticosteroids, and NSAIDs was in the range of -1.41 to 1.37, 0.72 to 2.97, and -0.98 to 2, respectively. The % mitochondrial uptake increased exponentially with an increase in Log D for each class of drugs, with the uptake at a given lipophilicity obeying the rank order cationic>anionic>neutral. Valinomycin reduced membrane potential and the delivery of positively charged propranolol and betaxolol. The best equation for the combined data set was Log % Uptake = 0.333 Log D + 0.157 Charge - 0.887 Log PSA + 2.032 (R(2) = 0.738). CONCLUSIONS: Drug lipopohilicity, charge, and polar surface area and membrane potential influence mitochondrial drug delivery, with the uptake of positively charged, lipophilic molecules being the most efficient.

Probenecid treatment enhances retinal and brain delivery of N-4-benzoylaminophenylsulfonylglycine: an anionic aldose reductase inhibitor.

Anion efflux transporters are expected to minimize target tissue delivery of N-[4-(benzoylaminophenyl)sulfonyl]glycine (BAPSG), a novel carboxylic acid aldose reductase inhibitor, which exists as a monocarboxylate anion at physiological conditions. Therefore, the objective of this study was to determine whether BAPSG delivery to various eye tissues including the retina and the brain can be enhanced by probenecid, a competitive inhibitor of anion transporters. To determine the influence of probenecid on eye and brain distribution of BAPSG, probenecid was administered intraperitoneally (120 mg/kg body weight; i.p.) 20 min prior to BAPSG (50 mg/kg; i.p.) administration. Drug disposition in various eye tissues including the retina and the brain was determined at 15 min, 1, 2 and 4h after BAPSG dose in male Sprauge-Dawley rats. To determine whether probenecid alters plasma clearance of BAPSG, influence of probenecid (120 mg/kg; i.p.) on the plasma pharmacokinetics of intravenously administered BAPSG (15 mg/kg) was studied as well. Finally, the effect of probenecid co-administration on the ocular tissue distribution of BAPSG was assessed in rabbits following topical (eye drop) administration. Following pretreatment with probenecid in the rat study, retinal delivery at 1h was increased by about 11-fold (2580 ng/g vs. 244 ng/g; p<0.05). Further, following probenecid pretreatment, significant BAPSG levels were detectable in the brain (45 + or - 20 ng/g) at 1h, unlike controls where the drug was not detectable. Plasma concentrations, plasma elimination half-life, and total body clearance of intravenously administered BAPSG were not altered by i.p. probenecid pretreatment. In the topical dosing study, a significant decline in BAPSG delivery was observed in the iris-ciliary body but no significant changes were observed in other tissues of the anterior segment of the eye including tears. Thus, inhibition of anion transporters is a useful approach to elevate retinal and brain delivery of BAPSG.

Development and in-vitro evaluation of sustained release poloxamer 407 (P407) gel formulations of ceftiofur.

The objective of this study was to develop sustained release Poloxamer 407 (P407) gel formulations of ceftiofur for treating foot infections in cattle. The formulations contained 25-35% (w/v) P407 alone or with polyvinyl pyrrolidone (PVP), carboxy methylcellulose (CMC), or hydroxylpropyl methylcellulose (HPMC) as an additive. The in-vitro release profiles of ceftiofur from the P407 formulations and the gel dissolution profiles were obtained simultaneously. Ceftiofur release followed zero order kinetics and correlated well with the weight percentage of P407 dissolved, indicating that the overall rate of release of ceftiofur is controlled by dissolution of the P407. An increase in P407 content from 25 to 35% resulted in a decrease in the rate of ceftiofur release. However, it appears that other factors may have also affected the drug release rate. Inclusion of PVP, CMC, and HPMC in the gel decreased the rate of release of ceftiofur to some extent. A decrease in the temperatures of the release medium decreased the release rate of ceftiofur, but not the rate of gel dissolution. The pH of the release medium showed a very slight effect on the release of ceftiofur and did not affect gel dissolution due to the non-ionic nature of P407.