Periodic Reporting for period 3 - NanoGut (Exploiting the pathophysiology of the gut towards innovative oral peptide delivery strategies)
Période du rapport: 2023-01-01 au 2024-06-30
The development of new oral drug delivery systems that will enable the absorption of therapeutic peptides to the systemic circulation is one of the greatest current challenges in drug delivery and is the ‘holy grail’ of peptide delivery. Improved novel drug delivery systems are of utmost importance in order to fulfill the potential of the oral route of administration in the treatment of chronic diseases (e.g. type 2 diabetes mellitus), where daily injections are often required. The number of peptides administered orally is very low and this is due to the instability of these molecules at the gastrointestinal site leading to a low bioavailability (around 1%). Newly developed drug delivery systems for oral peptide delivery rely on the absorption of the peptide, using the drug delivery system merely as a vehicle. I hypothesized that for certain peptides we could mimic the lipid ligands that physiologically trigger their secretion in the body via lipid-based drug delivery systems. I was the first to demonstrate that lipid-based nanocarriers stimulate endogenous glucagon-like peptide (GLP)-1 and GLP-2 secretion in vivo after orally administered to mice. This dual-action strategy would allow us to provide simultaneously with plasmatic levels of the synthetic encapsulated peptide and endogenous secretion of the peptide, potentially leading to improved concentrations of the peptide and decreased doses of peptide to be administered in the treatment of gastrointestinal disorders.
In the first part of the project, we have exploited our dual-action strategy towards improved GLP-1 delivery in the context of type 2 diabetes mellitus treatment. First, we developed a lipid-based nanocapsule that could induce GLP-1 secretion both in vitro and in vivo per se, without the addition of any supplementary peptide. Then, we included within our nanocarrier exenatide, a GLP-1 analog with a short half-life of 2.5 h. We evaluated in vivo in acute and chronic murine models of the disease the pharmacological effect of our formulation, comparing the effect of our oral strategy with the marketed subcutaneous injection. We observed that exenatide-loaded lipid nanocarriers-treated mice exhibited normalised plasma glucose levels comparable to those of untreated control mice, along with decreased insulin levels. We have demonstrated that our approach led to comparable results regarding glucose homeostasis to those observed for the current marketed drug that is administered subcutaneously. The non-inferiority of our approach together with the benefit of administration by the oral route for chronic treatments was highlighted. We further demonstrated that by tailoring the surface of the nanocarriers, we could increase GLP-1 secretion leading to a less frequent administration of the formulation rendering the same pharmacological effect. Thus, we can tailor the surface of these nanocarriers in order to provide with improved peptide stimulation in vivo. We are currently conducting mechanistic studies to understand how are these nanoparticles stimulating the secretion of peptides and how can we tune this effect by modifying the physicochemical properties of the nanocarriers.
The results of the project so far have demonstrated that lipid-based nanocarriers do stimulate the secretion of gastrointestinal peptides (e.g. GLP-1 and GLP-2) via oral route mimicking the lipid ligands found in the gut lumen that trigger the secretion of these peptides. The secreted levels, along with the plasmatic levels of the encapsulated peptide, provide with sufficient stimulus as per inducing a pharmacological effect in vivo. This opens a new pave of treatments in which the drug delivery system is not merely a vehicle but a contributor to the ultimate therapeutic effect of the formulation. The efficacy of the formulation has been evaluated in the context of type 2 diabetes treatment for the delivery of GLP-1, evaluating the ability of the nanocarrier to induce endogenous GLP-1 secretion. We have also proven the ability of the formulation to induce GLP-2 secretion. In this context, the main breakthrough would be to demonstrate the ability of the formulation to induce mucosal healing in the context of inflammatory bowel diseases. We expect to better understand how these nanocarriers exert their effect in vivo and how can we tune this effect modifying different properties of the nanocarriers (e.g. size, lipid composition). We will also evaluate the impact of the physico-chemical properties of the nanocarriers, and thus the composition of the formulation, on the microbiota. The final goal of the project is to demonstrate that the stimulation of gut hormones using lipid-based nanocarriers could represent a novel plausible strategy towards the treatment of gastrointestinal disorders.