METFORMIN ANTHELMINTHIC EFFECTS ASSOCIATED WITH A DECREASE IN PARASITIC GLUCOSE AND GLYCOGEN IN VIVO

JULIA A. LOOS; FACUNDO J. SALINAS; PAULA TABORDA; ULISES NOTARO; LUCIANO LAUSERO; HUGO ORTEGA; ANDREA CUMINO

Mar del Plata

Congreso; LXVIII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2023

REUNIÓN CONJUNTA AACYTAL, AAFE, SAB y SAIC 2023

Most patients with cystic echinococcosis (CE) are diagnosed at advanced disease stages when the therapy with benzimidazoles is limited, being imperative new therapeutic approaches. Since in cestodes, glycogen is the main energy storage molecule and glucose the major fermentative substrate, we aim to target the energy production pathways in the parasite. Here, we assess the efficacy of metformin as an indirect AMPK agonist in experimental models of advanced CE, at 6 and 12 months post-infection, employing the highest dose of the drug tested (250 mg kg-1 day-1) orally or intraperitoneally, respectively. Based on in situ detection of fluorescent glycogen with 2‑NBDG, biochemical determinations of hydatid fluid, and biodistribution analysis of IRDye-800CW2-DG in mouse whole-body (using near-infrared fluorescent in vivo imaging combined with 3D optical tomography), we demonstrated that metformin increased glucose utilization in metacestodes through the glycolytic pathway, leading to the elevation of intracystic lactate levels (up to 7-10 mM), with a tendency to increase the glucose uptake in peritoneal cavity tissues of infected mice. Given that Echinococcus cells cannot oxidize lactate, it would diffuse to the surrounding tissue, activating signal transduction pathways involved in the differentiation of macrophages, fibroblasts and lymphocytes, and promoting the development of the cystic adventitial layer. By biochemistry and molecular approaches, we demonstrated intracystic accumulation of metformin at supra-pharmacological concentrations (>1 mM), which induced mitochondrial complex I inhibition and increased cellular Pi/ATP ratio, with AMPK activation and TOR inhibition (by dephosphorylation in Ser3122) and, consequently, reduction of the Warburg effect and proliferation in germinal cells. In the context of normoglycemic mice, our results are in accordance with previous data showing glucose reduction in gut-liver crosstalk induced by metformin.