RESUMO
Sodium alendronate (ALN) is a very hydrosoluble and poorly permeable molecule used as an antiresorptive agent and with vascular anticalcifying capacity. Loaded into targeted nanovesicles, its anti-inflammatory activity may be amplified towards extra-osseous and noncalcified target cells, such as severely irritated vascular endothelium. Here cytotoxicity, mitochondrial membrane potential, ATP content, and membrane fluidity of human endothelial venous cells (HUVECs) were determined after endocytosis of ALN-loaded nanoarchaeosomes (nanoARC-Chol(ALN), made of polar lipids from Halorubrum tebenquichense: cholesterol 7:3 w/w, 166 ± 5 nm, 0.16 ± 0.02 PDI, -40.8 ± 5.4 mV potential, 84.7 ± 21 µg/mg ALN/total lipids, TL). The effect of nanoARC-Chol(ALN) was further assessed on severely inflamed HUVECs. To that aim, HUVECs were grown on a porous barrier on top of a basal compartment seeded either with macrophages or human foam cells. One lighter and one more pronounced inflammatory context was modelled by adding lipopolysaccharide (LPS) to the apical or the apical and basal compartments. The endocytosis of nanoARC-Chol(ALN), was observed to partly reduce the endothelial-mesenchymal transition of HUVECs. Besides, while 10 mg/mL dexamethasone, 7.6 mM free ALN and ALN-loaded liposomes failed, 50 µg/mL TL + 2.5 µg/mL ALN (i.e., nanoARC-Chol(ALN)) reduced the IL-6 and IL-8 levels by, respectively, 75% and 65% in the mild and by, respectively, 60% and 40% in the pronounced inflammation model. This is the first report showing that the endocytosis of nanoARC-Chol(ALN) by HUVECs magnifies the anti-inflammatory activity of ALN even under conditions of intense irritation, not only surpassing that of free ALN but also that of dexamethasone.
RESUMO
Oxidative stress plays an essential role in the pathogenesis and progression of inflammatory bowel disease. Co-administration of antioxidants and anti-inflammatory drugs has shown clinical benefits. Due to its significant reactive oxygen species (ROS) scavenging ability, great interest has been focused on superoxide dismutase (SOD) for therapeutic use. However, oral SOD is exposed to biochemical degradation along gastrointestinal transit. Furthermore, the antioxidant activity of SOD must be achieved intracellularly, therefore its cell entry requires endocytic mediating mechanisms. In this work, SOD was loaded into nanoarchaeosomes (ARC-SOD), nanovesicles fully made of sn 2,3 ether linked phytanyl saturated archaeolipids to protect and target SOD to inflammatory macrophages upon oral administration. Antioxidant and anti-inflammatory activities of ARC-SOD, non-digested and digested in simulated gastrointestinal fluids, on macrophages stimulated with H2O2 and lipopolysaccharide were determined and compared with those of free SOD and SOD encapsulated into highly stable liposomes (LIPO-SOD). Compared to SOD and LIPO-SOD, ARC-SOD (170 ± 14 nm, -30 ± 4 mV zeta potential, 122 mg protein/g phospholipids) showed the highest antioxidant and anti-inflammatory activity: it reversed the cytotoxic effect of H2O2, decreased intracellular ROS and completely suppressed the production of IL-6 and TNF-α on stimulated J774 A.1 cells. Moreover, while the activity of LIPO-SOD was lost upon preparation, gastrointestinal digestion and storage, ARC-SOD was easy to prepare and retained its antioxidant capacity upon digestion in simulated gastrointestinal fluids and after 5 months of storage. Because of their structural and pharmacodynamic features, ARC-SOD may be suitable for oral targeted delivery of SOD to inflamed mucosa.