Micellar Nanocarriers of Hydroxytyrosol Are Protective against Parkinson’s Related Oxidative Stress in an In Vitro hCMEC/D3-SH-SY5Y Co-Culture System

Abstract

Hydroxytyrosol (HT) is a natural phenolic antioxidant which has neuroprotective effects in models of Parkinson’s disease (PD). Due to issues such as rapid metabolism, HT is unlikely to reach the brain at therapeutic concentrations required for a clinical effect. We have previously developed micellar nanocarriers from Pluronic F68® (P68) and dequalinium (DQA) which have suitable characteristics for brain delivery of antioxidants and iron chelators. The aim of this study was to utilise the P68 + DQA nanocarriers for HT alone, or in combination with the iron chelator deferoxamine (DFO), and assess their physical characteristics and ability to pass the blood–brain barrier and protect against rotenone in a cellular hCMEC/D3-SH-SY5Y co-culture system. Both HT and HT + DFO formulations were less than 170 nm in size and demonstrated high encapsulation efficiencies (up to 97%). P68 + DQA nanoformulation enhanced the mean blood–brain barrier (BBB) passage of HT by 50% (p < 0.0001, n = 6). This resulted in increased protection against rotenone induced cytotoxicity and oxidative stress by up to 12% and 9%, respectively, compared to the corresponding free drug treatments (p < 0.01, n = 6). This study demonstrates for the first time the incorporation of HT and HT + DFO into P68 + DQA nanocarriers and successful delivery of these nanocarriers across a BBB model to protect against PD-related oxidative stress. These nanocarriers warrant further investigation to evaluate whether this enhanced neuroprotection is exhibited in in vivo PD models.

In vitro study of the blood–brain barrier transport of bioactives from Mediterranean foods

“…78 TYR (10 and 100 μM) showed 50% transendothelial transport through the BBB endothelium, TYRS (20 and 2000 μM) showed 30%, and HT (1 and 100 μM) showed 70%, for both concentrations tested of each compound. Similarly, Mursaleen et al 75 obtained the same passing percentage for HT at 10 and 20 μM, even when they tested a shorter incubation time (1 hour). Hence, we can hypothesize that they may pass through the BBB by passive transport.…”

“…for both concentrations tested of each compound. Similarly, Mursaleen et al 75 obtained the same passing percentage for HT at 10 and 20 µM, even when they tested a shorter incubation time (1 hour). Hence, we can hypothesize that they may pass through the BBB by passive transport.…”

Protective Effect of Ergothioneine against 7-Ketocholesterol-Induced Mitochondrial Damage in hCMEC/D3 Human Brain Endothelial Cells

“…The hCMEC/D3 model is suitable for neurovascular and neurodegenerative disease studies because the cell line stably maintains a BBB phenotype [ 31 ], and BBB dysfunction is now well recognised to be associated with various neurodegenerative diseases [ 32 ]. Studies using this cellular model in Alzheimer’s disease [ 33 , 34 ] and Parkinson’s disease [ 35 , 36 ] have provided crucial insights on disease pathology and possible treatments. 7KC was found to induce approximately 60% cell death and loss of cell viability in hCMEC/D3 brain endothelial cells, using Trypan blue and MTS assay, respectively, and 7KC-induced cytotoxicity was significantly reduced by cotreatment with ET.…”

Co-Culture Models: Key Players in In Vitro Neurotoxicity, Neurodegeneration and BBB Modeling Studies

“…In 2021, Mursaleen and colleagues developed an in vitro co-culture model of immortalized endothelial cells, hCMEC/D3 cells, with the neuroblastoma cell line, SH-SY5Y that elucidates the BBB modeling for drug delivery and target validation [ 152 ]. In in vivo studies, hydroxytyrosol has shown a low capacity to cross the BBB.…”

“…In in vivo studies, hydroxytyrosol has shown a low capacity to cross the BBB. To overcome this problem, the authors used micellar nanocarriers to enhance the passage across the BBB and used rotenone (concentration of 100 µM) to mimic a PD phenotype [ 152 ]. They showed that micellar nanocarriers containing hydroxytyrosol were capable of crossing the BBB, in vitro, without causing cytotoxicity, and protected the neuronal SH-SY5Y cells against rotenone-induced oxidative stress (assessing by mitochondrial hydroxyl levels) [ 152 ].…”