Towards potent anti-inflammatory therapies in atherosclerosis: The case of methotrexate and colchicine combination into compartmentalized liposomes

Inflammation is a key hallmark in atherosclerosis initiation, progression, and thrombotic manifestations. Several studies have used potent anti-inflammatory drugs, such as methotrexate (MTX) and colchicine (COL), for the treatment of atherosclerosis returning only modest improvements. This should be mostly ascribed to the complexity of the disease and the poor bioavailability and tissue specificity of the freely administered anti-inflammatory drugs. Hence, to overcome these limitations, the current work explores the efficacy of a combination therapy resulting from the co-encapsulation of MTX and COL into liposomes. MTX-lipid conjugate of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) were first synthesized and integrated into the lipid bilayer of liposomes containing aqueous cores enriched with COL. These combination liposomes (Combo-LIP) were realized using an automated microfluidic system and exhibited an average size of 100 nm with long colloidal stability. Encapsulation efficiencies as high as ∼30% for MTX and COL combined were documented at a 16:1 drug ratio. In primary bone marrow derived monocytes (BMDM), Combo-LIP significantly ameliorated LPS-induced inflammation with up to a 3-fold reduction in the expression of IL-1β and IL-6. Similar results were also documented for oxidized low-density lipoprotein (oxLDL) – induced inflammation. Furthermore, Combo-LIP supported the overexpression of ABCA1 and downregulation of CD36 and SRA-1, reducing the overall accumulation of oxLDL into macrophages. Collectively these preliminary results vividly suggest that the liposomal reformulation of MTX and COL could mitigate cell inflammation and possibly halt the progression of atherosclerosis.