Ana Beloqui

L cells are enteroendocrine cells located throughout the gastrointestinal tract that secrete physiologically important peptides. The most characterized peptides secreted by L cells are the peptide YY (PYY) and the glucagon-like peptides 1 (GLP-1) and 2 (GLP-2). These peptides are released rapidly into the circulation after oral nutrient ingestion. Recently, lipid-based nanoparticles (NP) have been described as triggers for GLP-1 secretion by L cells. NP physicochemical properties play a key role in the NP-cell interaction, and drive NP cell internalization. We herein hypothesize that lipid-based NP with appropriate size would not only be able to deliver drugs into blood circulation but also act like endogenous ligands to stimulate GLP-1 secretion. We tested five different size (25, 50, 100, 150, and 200 nm) lipid nanocapsules (LNC) on murine L cells in vitro to confirm this hypothesis. Our study showed that GLP-1 secretion was induced only by the 200 nm size LNC, highlighting the im...

Nanoparticulate based drug delivery systems have been extensively studied to efficiently encapsulate and deliver peptides orally. However, most of the existing data mainly focus on the nanoparticles as a drug carrier, but the ability of nanoparticles having a biological effect has not been exploited. Herein, we hypothesize that nanostructured lipid carriers (NLCs) could activate the endogenous glucagon-like peptide-1 (GLP-1) secretion and also act as oral delivery systems for GLP-1 analogs (exenatide and liraglutide). NLCs effectively encapsulated the peptides, the majority of which were only released under the intestinal conditions. NLCs, with and without peptide encapsulation, showed effective induction of GLP-1 secretion in vitro from the enteroendocrinal L-cells (GLUTag). NLCs also showed a 2.9-fold increase in the permeability of exenatide across the intestinal cell monolayer. The intestinal administration of the exenatide and liraglutide loaded NLCs did not demonstrate any glu...

The specialized microfold cells (M cells) in the follicle-associated epithelium (FAE) of intestinal Peyer's patches serve as antigen-sampling cells of the intestinal innate immune system. Unlike 'classical' enterocytes, they are able to translocate diverse particulates without digesting them. They act as pathways for microorganism invasion and mediate food tolerance by transcellular transport of intestinal microbiota and antigens. Their ability to transcytose intact particles can be used to develop oral drug delivery and oral immunization strategies. This protocol describes a reproducible and versatile human M-cell-like in vitro model. This model can be exploited to evaluate M-cell transport of microparticles and nanoparticles for protein, drug or vaccine delivery and to study bacterial adherence and translocation across M cells. The inverted in vitro M-cell model consists of three main steps. First, Caco-2 cells are seeded at the apical side of the inserts. Second, the ...

Single-layer protamine and double layer polysialic acid (PSA)/protamine nanocapsules (NCs) were designed in order to be used as carriers to facilitate the transport of macromolecules across the intestinal epithelium. The rational for the design of these NCs was based on that protamine is a non-toxic yet potent cell-penetrating peptide, capable of translocating protein cargos through cell membranes, while PSA is a low molecular weight polysaccharide used to enhance the stability of macromolecules and nanocarriers. The aim of this work was to study in vitro the mechanism of interaction of these NCs with different intestinal cell models (Caco-2, Caco-2/Raji mimicking follicle associated epithelium and Caco-2/HT29-MTX to study the effect of mucus). For this, a fluorescent marker, TAMRA was covalently linked to protamine. The interaction and transport of the NCs with the Caco-2 cells was found to be concentration, temperature and size dependent. In all cases, the double layer PSA-protamine NCs exhibited a significantly higher transport compared to protamine NCs. On the other hand, the transport of the NCs was significantly higher in the co-culture (Caco-2/Raji monolayer) compared to the monoculture model (Caco-2 monolayer), implying that M cells are involved in the transport of these nanosystems. The formulations, administered intra-jejunally to healthy rats (4h fasting) resulted in a moderate reduction of the glucose levels (20% reduction), which lasted for up to 4h. This work raises prospects that protamine-based nanocapsules may have the potential as oral peptide delivery nanocarriers.

Unraveling the mechanisms of nanoparticle transport across the intestinal barrier is essential for designing more efficient nanoparticles for oral administration. The physicochemical parameters of the nanoparticles (e.g., size, surface charge, chemical composition) dictate nanoparticle fate across the intestinal barrier. This review aims to address the most important findings regarding polymeric and lipidic nanoparticle transport across the intestinal barrier, including the evaluation of critical physicochemical parameters of nanoparticles that affect nanocarrier interactions with the intestinal barrier.

Cyclosporine A (CsA) is a well-known immunosuppressive agent used as rescue therapy in severe steroid-refractory ulcerative colitis (UC). However, toxicity issues associated with CsA when administered in its commercially available formulations have been reported in clinical practice. Since nanotechnology has been proposed as a promising strategy to improve safety and efficacy in the treatment of inflammatory bowel disease (IBD), the main purpose of this study was to evaluate the effect of oral administration of CsA-loaded lipid nanoparticles (LN) in the dextran sodium sulfate (DSS)-induced colitis mouse model using Sandimmune Neoral(®) as reference. The results showed that the formulations used did not decrease colon inflammation in terms of myeloperoxidase activity (MPO), tumor necrosis factor (TNF)-α expression, or histological scoring in the acute stage of the disease. However, further studies are needed in order to corroborate the efficacy of these formulations in the chronic phase of the disease.

Cyclosporine A (CsA) is a well-known immunosuppressive agent that gained considerable importance in transplant medicine in the late 1970s due to its selective and reversible inhibition of T-lymphocytes. While CsA has been widely used to prevent graft rejection in patients undergoing organ transplant it was also used to treat several systemic and local autoimmune disorders. Currently, the neuro- and cardio-protective effects of CsA (CiCloMulsion®; NeuroSTAT®) are being tested in phase II and III trials respectively and NeuroSTAT® received orphan drug status from US FDA and Europe in 2010. The reformulation strategies focused on developing Cremophor® EL free formulations and address variable bioavailability and toxicity issues of CsA. This review is an attempt to highlight the progress made so far and the room available for further improvements to realize the maximum benefits of CsA.

Selective drug delivery to inflamed tissues is of widespread interest for the treatment of inflammatory bowel disease (IBD). Because a lack of physiological lipids has been described in patients suffering IBD, and some lipids present immunomodulatory properties, we hypothesize that the combination of lipids and anti-inflammatory drugs together within a nanocarrier may be a valuable strategy for overcoming IBD. In the present study, we investigated and compared the in vitro and in vivo efficacy of three lipid-based nanocarriers containing curcumin (CC) as an anti-inflammatory drug for treating IBD in a murine DSS-induced colitis model. These nanocarriers included self-nanoemulsifying drug delivery systems (SNEDDS), nanostructured lipid carriers (NLC) and lipid core-shell protamine nanocapsules (NC). In vitro, a 30-fold higher CC permeability across Caco-2 cell monolayers was obtained using NC compared to SNEDDS (NC>SNEDDS>NLC and CC suspension). The CC SNEDDS and CC NLC but not...

Over the last years, the interest of the pharmaceutical industry in the use of therapeutic peptides in diabetes treatment has been increased. However, these are restricted to parenteral administration. In order to mimic the natural physiological response, many efforts have been made towards oral peptide delivery in diabetes treatment. This review article aims to give an overview on the progress in the nanomedicine field towards the design and optimization of nanoparticle-based drug delivery systems capable of overcoming the harsh gastrointestinal environment and achieving an adequate bioavailability following oral administration. The reported data clearly illustrate the promise of nanomecidine for antidiabetic oral peptide delivery.

The aim of this study was to develop a nanostructured lipid carriers (NLC) formulation containing spironolactone (SPN-NLCs), and to investigate its potential for the oral delivery of poorly water-soluble compounds. SPN-NLCs were orally administered to rabbits and the pharmacokinetics of spironolactone and its metabolites was evaluated. As reference formulation, we administered syrup. Spironolactone was only detected in a few plasma samples; hence, metabolite levels were employed for the pharmacokinetic analysis. The absolute bioavailability of 7α-TMS was significantly higher with the syrup than those obtained with the SPN-NLCs (0.7 versus 0.4, p < 0.05). However, no significant differences were observed in the bioavailability of canrenone, revealing a different canrenone/7α-TMS ratio depending on the administered formulation. Orally administered (99m)Tc-radiolabeled SPN-NLCs were mainly detected in the small intestine. These results suggest the retention of the nanocarriers in the underlying epithelium and further uptake by the epithelial cells.