Carboxymethylcellulose biofunctionalized ternary quantum dots for subcellular-targeted brain cancer nanotheranostics.

Among the most lethal forms of cancer, malignant brain tumors persist as one of the greatest challenges faced by oncologists, where nanotechnology-driven theranostics can play a critical role in developing novel polymer-based supramolecular nanoarchitectures with multifunctional and multi-modal characteristics to fight cancer. However, it is virtually a consensus that, besides the complexity of active delivering anticancer drugs by the nanocarriers to the tumor site, the current evaluation methods primarily relying on in vitro assays and in vivo animal models have been accounted for the low translational effectiveness to clinical applications. In this view, the chick chorioallantoic membrane (CAM) assay has been increasingly recognized as one of the best preclinical models to study the effects of anticancer drugs on the tumor microenvironment (TME). Thus, in this study, we designed, characterized, and developed novel hybrid nanostructures encompassing chemically functionalized carboxymethylcellulose (CMC) with mitochondria-targeting pro-apoptotic peptide (KLA) and cell-penetrating moiety (cysteine, CYS) with fluorescent inorganic semiconductor (Ag-In-S, AIS) for simultaneously bioimaging and inducing glioblastoma cancer cell (U-87 MG, GBM) death. The results demonstrated that the CMC-peptide macromolecules produced supramolecular vesicle-like nanostructures with aqueous colloidal stability suitable as nanocarriers for passive and active targeting of cancer tumors. The optical properties and physicochemical features of the nanoconjugates confirmed their suitability as photoluminescent nanoprobes for cell bioimaging and intracellular tracking. Moreover, the results in vitro demonstrated a notable killing activity towards GBM cells of cysteine-bearing CMC conjugates coupled with pro-apoptotic KLA peptides. More importantly, compared to doxorubicin (DOX), a model anticancer drug in chemotherapy that is highly toxic, these innovative nanohybrids nanoconjugates displayed higher lethality against U-87 MG cancer cells. In vivo CAM assays validated these findings where the nanohybrids demonstrated a significant reduction of GBM tumor progression (41% area) and evidenced an antiangiogenic activity. These results pave the way for developing polymer-based hybrid nanoarchitectonics applied as targeted multifunctional theranostics for simultaneous imaging and therapy against glioblastoma while possibly reducing the systemic toxicity and side-effects of conventional anticancer chemotherapeutic agents.

Rosmarinic Acid Intravitreal Implants: A New Therapeutic Approach for Ocular Neovascularization.

Rosmarinic acid, a plant-derived compound with antiangiogenic activity, can be applied for the treatment of ocular diseases related to neovascularization, such as diabetic retinopathy, macular edema, and age-related macular degeneration. These diseases represent the leading causes of blindness worldwide if they are not properly treated. Intravitreal devices allow for localized drug delivery to the posterior segment, increasing the drug bioavailability and promoting extended release, thus, reducing side effects and enhancing the patient's compliance to the treatment. In this work, rosmarinic acid-loaded poly lactic-co-glycolic acid intraocular implants were developed with a view for the treatment of ocular neovascularization. Physical-chemical, biocompatibility, and safety studies of the implants were carried out in vitro and in vivo as well as an evaluation of the antiangiogenic activity in a chorioallantoic membrane assay. Data obtained showed that rosmarinic acid released from the implants was quantified in the vitreous for 6 weeks, while when it was in the solution formulation, after 24 h, no drug was found in the vitreous. The delivery device did not show any sign of toxicity after clinical evaluation and in electroretinographic findings. Histological analysis showed normal eye tissue. Rosmarinic acid released from implants reduced 30% of new vessel's formation. The intravitreal implant successfully allowed for the prolonged release of rosmarinic acid, was safe to rabbits eyes, and demonstrated activity in vessel reduction, thus demonstrating potential in preventing neovascularization in ophthalmic diseases.

Successful growth of fresh retinoblastoma cells in chorioallantoic membrane.

The authors developed a retinoblastoma model using fresh harvested cells from an enucleated eye that were transplanted in chick embryos (chorioallantoic membrane model). The transplanted embryos were treated with escalating doses of Melphalan. This exploratory model was developed with the goal of testing drug sensitivity. Our findings suggest this tumor model could be employed to personalize treatment for patients with retinoblastoma, especially those with bilateral and more refractory disease.

Anti-Toxoplasma activity and impact evaluation of lyophilization, hot molding process, and gamma-irradiation techniques on CLH-PLGA intravitreal implants.

Intraocular delivery systems have been developed to treat many eye diseases, especially those affecting the posterior segment of the eye. However, ocular toxoplasmosis, the leading cause of infectious posterior uveitis in the world, still lacks an effective treatment. Therefore, our group developed an intravitreal polymeric implant to release clindamycin, a potent anti-Toxoplasma antibiotic. In this work, we used different techniques such as differential scanning calorimetry, thermogravimetry, X-ray diffraction, scanning electron microscopy, and fourier-transform infrared spectroscopy to investigate drug/polymer properties while manufacturing the delivery system. We showed that the lyophilization, hot molding process, and sterilization by gamma irradiation did not change drug/polymer physical-chemistry properties. The drug was found to be homogeneously dispersed into the poly lactic-co-glycolic acid (PLGA) chains and the profile release was characterized by an initial burst followed by prolonged release. The drug profile release was not modified after gamma irradiation and non-covalent interaction was found between the drug and the PLGA. We also observed the preservation of the drug activity by showing the potent anti-Toxoplasma effect of the implant, after 24-72 h in contact with cells infected by the parasite, which highlights this system as an alternative to treat toxoplasmic retinochoroiditis.

In vivo release and retinal toxicity of cyclosporine-loaded intravitreal device.

PURPOSE: To determine the in vivo release profile and retinal safety of cyclosporine A (CsA) delivered from a biodegradable poly-lactide-co-glycolide (PLGA) device in the vitreous cavity of rabbits' eyes. METHODS: A total of 60 animals (60 eyes) divided into two groups were used. For the in vivo release study, 32 eyes received PLGA implants containing 350 µg of CsA, and 16 eyes received the implants without drug (control). Four animals of CsA group and two of the control group were killed weekly until 8 weeks; the vitreous was removed, and CsA concentration was evaluated. Ophthalmological examination was performed in the animals prior to implant placement and weekly during the study period. Electroretinography (ERG) was performed in other six animals for each group, treated and control, at the beginning and at the end of the study (8 weeks) when they were killed and had their eyes processed for histology. RESULTS: No sign of inflammation was noticed on slit lamp examinations and the IOP maintained stable during the study period in CsA and control groups. CsA concentration in the vitreous (ng/ml) was 257.07 ± 117.23, 271.15 ± 98.96, 296.66 ± 86.25, 256.27 ± 99.22, 304.50 ± 88.18, 326.35 ± 105.24, 491.25 ± 119.90 and 589.93 ± 132.55 after 1, 2, 3, 4, 5, 6, 7 and 8 weeks of implantation, respectively. At the end of the study, 21.67 % of mass loss was found. The retina did not show any histological alteration in either group, but a significant reduction in dark-adapted b-wave amplitude was observed in the CsA group, with no changes in a-wave amplitude. CONCLUSIONS: These data show that the PLGA system is safe, but the selective reduction in ERG b-wave amplitude indicates that the PLGA with 350 µg CsA causes retinal function impairment, specifically on the rod postreceptor pathway, 8 weeks after implantation. These ERG changes were not associated with any histological damage as seen at the light microscopy level.

Tacrolimus-loaded PLGA implants: in vivo release and ocular toxicity.

PURPOSE: To evaluate the in vivo release and ocular toxicity of a tacrolimus-loaded PLGA intravitreal implant. METHODS: Tacrolimus-loaded PLGA implants were inserted into the vitreous cavity of rabbits' eye. At different time points, the vitreous was retrieved and the concentration of tacrolimus released from the implants was determined. Clinical examination was performed to evaluate the implant tolerance. RESULTS: PLGA implants provided controlled and prolonged release of tacrolimus. Approximately 99.97% of the drug was released from the devices at 6 weeks. Ophthalmic examination revealed no evidence of toxic effects of implants. CONCLUSIONS: Tolerance and feasibility of the tacrolimus-loaded PLGA implants, as sustained intraocular drug delivery systems, were demonstrated.

In vivo release and retinal safety of intravitreal implants of thalidomide in rabbit eyes and antiangiogenic effect on the chorioallantoic membrane.

PURPOSE: To evaluate the in vivo release, retinal safety and antiangiogenic effect of a thalidomide-loaded poly-lactide-co-glycolide intravitreal implant. METHODS: New Zealand white rabbits, divided into two groups, I and II, received an intravitreal implant containing or not thalidomide, respectively (n = 12). Intravitreal drug levels were determined during a six-week study period. The potential for toxicity associated with the implants was evaluated by electroretinography and light microscopy (n = 8). Twelve chorioallantoic membranes (CAMs) from chicken eggs were incubated with thalidomide dispersion, implants containing or not thalidomide and vitreous samples and analyzed after two days regarding the percentage of vessels regression. RESULTS: Intravitreal concentrations of thalidomide (ng/ml) were 690.21 ± 177.95, 372.51 ± 185.56, 240.59 ± 133.48, 327.54 ± 169.71, 294.26 ± 142.41 and 465.18 ± 157.51 at 1, 2, 3, 4, 5 and 6 weeks, respectively, after implantation in group I rabbits. No drug was detected in group II samples. Electroretinography and histological evaluations did not show any sign of retina toxicity. There was significant regression of vessels in CAM incubated with thalidomide dispersion, thalidomide-loaded implants and vitreous samples from group I when compared to control. CONCLUSION: The intravitreal implants delivered safe doses of thalidomide that were also effective to induce vessels regression in CAMs.

Pharmacokinetic and toxicity investigations of a new intraocular lens with a dexamethasone drug delivery system: a pilot study.

AIM: To investigate the short-term safety and pharmacokinetic behavior of a new intraocular lens containing a dexamethasone drug delivery system (IOL-DDS) in rabbit eyes. METHODS: A modified polymethylmethacrylate IOL containing a biodegradable dexamethasone DDS was implanted into the posterior chamber of the right eyes of 9 New Zealand white rabbits. Serial slitlamp and indirect ophthalmoscopic examinations (including grading of intraocular inflammation) were performed. After 3, 6 and 9 days, the rabbits were euthanized and the globes were removed for histological examination and for determination of dexamethasone levels in the aqueous humor and in the vitreous. Analysis of dexamethasone concentrations was performed by ELISA. RESULTS: Therapeutic concentrations of dexamethasone were detectable in the aqueous and vitreous of the study eyes throughout the 9-day period in all tested animals. The mean aqueous dexamethasone concentration (ng/ml, +/- SD) was 1,015.42 (+/- 43.05), 970.11 (+/- 32.47) and 757.58 (+/- 30.19) and the mean vitreous concentration (ng/ml, +/- SD) was 399.82 (+/- 38.05), 287.38 (+/-34.47) and 268.15 (+/- 32.00) at 3, 6 and 9 days after the surgical procedure, respectively. No corneal or retinal histological changes were observed during the study period. CONCLUSION: The IOL-DDS is effective in delivering therapeutic concentrations of dexamethasone to the aqueous and vitreous, without acute damage to the cornea and retina. Further controlled studies in the same animal model are under way to determine the potential value of this lens in the prevention and treatment of inflammation following cataract surgery.