Alonso González, Mario

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder, with its incidence constantly increasing. To date, there is no cure for the disease, with a need for new and effective treatments. Morin hydrate (MH) is a naturally occurring flavonoid of the Moraceae family with antioxidant and anti-inflammatory properties; however, the blood–brain barrier (BBB) prevents this flavonoid from reaching the CNS when aiming to potentially treat AD. Seeking to use the LAT-1 transporter present in the BBB, a nanoparticle (NPs) formulation loaded with MH and functionalized with phenylalanine-phenylalanine dipeptide was developed (NPphe-MH) and compared to non-functionalized NPs (NP-MH). In addition, two formulations were prepared using rhodamine B (Rh-B) as a fluorescent dye (NPphe-Rh and NP-Rh) to study their biodistribution and ability to cross the BBB. Functionalization of PLGA NPs resulted in high encapsulation efficiencies for both MH and Rh-B. Studies conducted in Wistar rats showed that the presence of phenylalanine dipeptide in the NPs modified their biodistribution profiles, making them more attractive for both liver and lungs, whereas non-functionalized NPs were predominantly distributed to the spleen. Formulation NPphe-Rh remained in the brain for at least 2 h after administration.

Rheumatoid arthritis (RA) is a chronic inflammatory disease with sulfasalazine (SSZ) extensively used for long-term treatment of both juvenile and adult RA. Its use is associated with adverse effects and toxicity due to its non-selective biodistribution. Macrophages play an important role in inflammatory processes. In order to target SSZ to macrophages in this work two microparticulate systems (MPs) are developed: SSZ-loaded PLGA MPs without and with -tocopherol, with particle sizes lower than 5 m and encapsulation efficiencies of 81.07 11% and 63.50 6.62%, respectively. Release of SSZ from MPs prepared with -tocopherol was prolonged for 20 days. In RAW264.7 cell macrophages MPs prepared with -tocopherol were captured faster. Cell viability studies confirmed that SSZ-loaded MPs prepared without and with -tocopherol did not produce cytotoxicity at the concentrations assayed. The anti-inflammatory activity of SSZ-loaded MPs was studied by quantifying interleukins IL-1, IL-6 and TNF- in macrophages. All formulations produced a significant reduction of cytokine concentrations after 24 and 72 h, indicating that release of SSZ from the MPs was able to inhibit the inflammatory response induced by lipopolysaccharide (LPS). Gene expression of IL-1, IL-6 and TNF- was decreased by SSZ-loaded MPs. SSZ-loaded MPs prepared with -tocopherol will potentially allow increasing the residence time of SSZ in the synovial cavity, prolonging its duration of action, and reducing the adverse effects associated with its non-selective biodistribution.

Neurodegenerative diseases are chronic disorders affecting millions of people with their prevalence constantly increasing worldwide. The blood-brain barrier plays a key role in the design of successful treatments for these pathologies. Nanotechnology has the potential to improve treatment of CNS disorders and facilitate effective drug transfer. For this, biodegradable poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) are promising strategies as they can be surface-tailored with functionalized molecules for site-specific brain targeting. In our work PLGA NPs loaded with a fluorescent marker (rhodamine B) and functionalized with glutathione or phenylalanine dipeptide have been developed, characterized and analyzed for their passage across the BBB and distribution in different brain areas of Wistar rats. Surface functionalization of the NPs with glutathione or phenylalanine (formulations NP-GSH-Rh and NP-PHE2-Rh) favoured their passage across the BBB process in which glutathione transporter and L-type amino acid transporter 1 (LAT-1) may be involved. One hour after their administration both functionalized formulations predominantly reached the hippocampus followed by the cortex and substantia nigra. Average values of intensity of fluorescence reached in the hippocampus showed statistically significant differences when compared to non-functionalized NPs and remained higher in this area 2 h after administration which allows us to highlight the potential importance of the results obtained as the presence of the NPs in the brain 2 h after their administration counteracts the efflux activity of the P-glycoprotein. In addition, none of the nanosystems caused tissue damage in the hippocampus, cortex or substantia nigra.