Co-liberación de agentes neuroprotectores a partir de sistemas microparticulares biodegradables: uso potencial en el tratamiento de patologías degenerativas del nervio óptico y la retina

Las patologías degenerativas que afectan al nervio óptico y la retina se caracterizan por ser devastadoras y comprometer significativamente la visión.En su mayoría son crónicas y cursan con un daño progresivo del nervio óptico y la pérdida de las células ganglionares de la retina (CGR), fotorreceptores y otras células retinianas, en un proceso que se conoce como neurodegeneración. En este proceso de patogénesis se encuentran implicados numerosos mecanismos de daño tales como el estrés oxidativo, la inflamación o la disfunción mitocondrial, que actúan además interaccionando entre sí. Esto, pone de manifiesto la complejidad y naturaleza multifactorial de estas enfermedades. Una de las estrategias terapéuticas encaminadas al tratamiento de las patologías neurodegenerativas es la neuroprotección, la cual se centra en prevenir, limitar, y en algunos casos revertir, la degeneración o muerte de las células neuronales. Además, dado que estas patologías presentan una etiología multifactorial, una actuación neuroprotectora múltiple con diversos agentes activos dirigidos frente a uno o varios mecanismos implicados en la patogénesis resulta sumamente interesante. Este enfoque terapéutico es lo que se conoce como terapia combinada o terapia de combinación..

Simultaneous co-delivery of neuroprotective drugs from multiloaded PLGA microspheres for the treatment of glaucoma

Glaucoma is a multifactorial neurodegenerative disorder and one of the leading causes of irreversible blindness globally and for which intraocular pressure is the only modifiable risk factor. Although neuroprotective therapies have been suggested to have therapeutic potential, drug delivery for the treatment of ocular disorders such as glaucoma remains an unmet clinical need, further complicated by poor patient compliance with topically applied treatments. In the present study we describe the development of multi-loaded PLGA-microspheres (MSs) incorporating three recognised neuroprotective agents (dexamethasone (DX), melatonin (MEL) and coenzyme Q10 (CoQ10)) in a single formulation (DMQ-MSs) to create a novel sustained-release intraocular drug delivery system (IODDS) for the treatment of glaucoma. MSs were spherical, with a mean particle size of 29.04 ± 1.89 μm rendering them suitable for intravitreal injection using conventional 25G-32G needles. Greater than 62% incorporation efficiency was achieved for the three drug cargo and MSs were able to co-deliver the encapsulated active compounds in a sustained manner over 30-days with low burst release. In vitro studies showed DMQ-MSs to be neuroprotective in a glutamate-induced cytotoxicity model (IC50 10.00±0.94 mM versus 6.89±0.82 mM in absence of DMQ-MSs) in R28 cell line. In vivo efficacy studies were performed using a well-established rodent model of chronic ocular hypertension (OHT), comparing single intravitreal injections of microspheres of DMQ-MSs to their equivalent individual single drug loaded MSs mixture (MSsmix), empty MSs, no-treatment OHT only and naïve groups. Twenty one days after OHT induction, DMQ-MSs showed a significantly neuroprotective effect on RGCs compared to OHT only controls. No such protective effect was observed in empty MSs and single-drug MSs treated groups. This work suggests that multi-loaded PLGA MSs present a novel therapeutic approach in the management of retinal neurodegeneration conditions such as glaucoma

Microspheres as intraocular therapeutic tools in chronic diseases of the optic nerve and retina

Pathologies affecting the optic nerve and the retina are one of the major causes of blindness. These diseases include age-related macular degeneration (AMD), diabetic Retinopathy (DR) and glaucoma, among others. Also, there are genetic disorders that affect the retina causing visual impairment. The prevalence of neurodegenerative diseases of the posterior segment are increased as most of them are related with the elderly. Even with the access to different treatments, there are some challenges in managing patients suffering retinal diseases. One of them is the need for frequent interventions. Also, an unpredictable response to therapy has suggested that different pathways may be playing a role in the development of these diseases. The management of these pathologies requires the development of controlled drug delivery systems able to slow the progression of the disease without the need of frequent invasive interventions, typically related with endophthalmitis, retinal detachment, ocular hypertension, cataract, inflammation, and floaters, among other. Biodegradable microspheres are able to encapsulate low molecular weight substances and large molecules such as biotechnological products. Over the last years, a large variety of active substances has been encapsulated in microspheres with the intention of providing neuroprotection of the optic nerve and the retina. The purpose of the present review is to describe the use of microspheres in chronic neurodegenerative diseases affecting the retina and the optic nerve. The advantage of microencapsulation of low molecular weight drugs as well as therapeutic peptides and proteins to be used as neuroprotective strategy is discussed. Also, a new use of the microspheres in the development of animal models of neurodegeneration of the posterior segment is described

A Safe GDNF and GDNF/BDNF Controlled Delivery System Improves Migration in Human Retinal Pigment Epithelial Cells and Survival in Retinal Ganglion Cells: Potential Usefulness in Degenerative Retinal Pathologies

We assessed the sustained delivery effect of poly (lactic-co-glycolic) acid (PLGA)/vitamin E (VitE) microspheres (MSs) loaded with glial cell-derived neurotrophic factor (GDNF) alone (GDNF-MSs) or combined with brain-derived neurotrophic factor (BDNF; GDNF/BDNF-MSs) on migration of the human adult retinal pigment epithelial cell-line-19 (ARPE-19) cells, primate choroidal endothelial (RF/6A) cells, and the survival of isolated mouse retinal ganglion cells (RGCs). The morphology of the MSs, particle size, and encapsulation efficiencies of the active substances were evaluated. In vitro release, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability, terminal deoxynucleotidyl transferase (TdT) deoxyuridine dUTP nick-end labelling (TUNEL) apoptosis, functional wound healing migration (ARPE-19; migration), and (RF/6A; angiogenesis) assays were conducted. The safety of MS intravitreal injection was assessed using hematoxylin and eosin, neuronal nuclei (NeuN) immunolabeling, and TUNEL assays, and RGC in vitro survival was analyzed. MSs delivered GDNF and co-delivered GDNF/BDNF in a sustained manner over 77 days. The BDNF/GDNF combination increased RPE cell migration, whereas no effect was observed on RF/6A. MSs did not alter cell viability, apoptosis was absent in vitro, and RGCs survived in vitro for seven weeks. In mice, retinal toxicity and apoptosis was absent in histologic sections. This delivery strategy could be useful as a potential co-therapy in retinal degenerations and glaucoma, in line with future personalized long-term intravitreal treatment as different amounts (doses) of microparticles can be administered according to patients’ needs

Diseño de herramientas para la adquisición de competencias transversales CT9, CT11, CT12 y CT13 que fomenten el desarrollo de habilidades de aplicación en la formación y competencia laboral de alumnos del Grado en Farmacia

A través de las competencias transversales comunes al Grado en Farmacia y a la materia Tecnología Farmacéutica se pretende dotar a los alumnos de herramientas para el desarrollo de habilidades necesarias en sus estudios y en su empleabilidad

Microsphere characterization.

<p>(A) Scanning electron microscopy picture of TUDCA-loaded microspheres. Insets: particle size distribution. (B) Cumulative <i>in vitro</i> release of TUDCA (μg/mg MSs) over 28 days from TUDCA-loaded PLGA MSs in PBS (pH 7.4).</p

Photoreceptor morphology in vehicle- and TUDCA-PLGA-MSs-treated eyes.

<p>Triple immunolabeling for cone arrestin (in green), VGLUT1 (in blue) and CtBP2 (in red) of retinal vertical sections from a P120 normal rat (Sprague Dawley, SD) (A) and P23H rats at P90 (B, C) and P120 (D, E), treated with unloaded PLGA MSs (B, D) or TUDCA-loaded PLGA MSs (C, E). Note that the typical cone pedicles (in green) containing synaptic vesicles (in blue) surrounding synaptic ribbons (in red) were less deteriorated in TUDCA-PLGA-MSs-treated P23H rats than in vehicle-treated animals. Scale bar, 10 μm.</p

Primary antibodies.

<p>Primary antibodies.</p

Electroretinographic responses in vehicle- and TUDCA-PLGA-MSs-treated eyes.

<p>Representative scotopic ERG traces from postnatal days P30 (A), P60 (B), P90 (C) and P120 (D) P23H rats treated with unloaded PLGA microspheres (<i>left</i>, <i>control</i>) or microspheres containing TUDCA (<i>right</i>, <i>TUDCA</i>). Units to the left of the panels indicate the flash luminance in log cd·s/m². Note that ERG responses reached higher values in eyes treated with TUDCA-PLGA MSs, as compared to vehicle-treated eyes.</p