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Molecular imaging as a tool to image drug delivery across the Blood Brain Barrier: OnconanoBBB project George Loudos Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece. Consortium: Technological Educational Institute of Athens (EL)
Molecular imaging as a tool to image drug delivery across the Blood Brain Barrier: OnconanoBBBprojectGeorge LoudosDepartment of Biomedical Engineering, Technological Educational Institute of Athens, Greece
Technological Educational Institute of Athens (EL)
University of Brighton (UK)
Coordinator : Prof. George Loudos (EL)e-mail: [email protected]
Traditional approaches to getting compounds into the brain are crude and include direct administration of therapeutic agents such as drugs or stem cells into the brain.
Pharmidex has developed a drug delivery system (Cerense™) that transiently and reversibly opens the BBB to entry of molecules into the brain without inducing tissue injury.
Cerense™ delivery technology unlocks the potential of CNS therapeutic opportunities by providing a novel technology that opens the blood–brain barrier.
Cerense™ has been shown to increase substantially the brain penetration of a chemotherapeutic agent and markedly enhance its chemotherapeutic efficacy.
Synthesis a range of nanoparticles for in vitro and in vivo assessment
Physicochemical characterisation (shape and size) of nanoparticles in different mediums
Optimise nanoparticles formulation using a variety of pharmaceutical excipients
Study mechanism of action (MOA) using high resolution imaging using endothelial cells both in vitro and in vivo
Labelling of nanoparticles with radioisotopes, without altering their biological properties
Assess the ability of nanoparticles to enhance transport of a diverse set of existing cancer drugs in in vitro models of BBB
Establish the in vivo pharmacokinetics Structural Distribution Relationship (SDR) for these nanoparticles via different administration routes
Establish the in vivo neuropharmacokinetics (brain pharmacokinetics) Structural Distribution Relationship (SDR) for these nanoparticles utilised via optimised route identified from above
Establish and validate imaging protocols for screening of Cerense™-formulated chemotherapeutics in models of brain cancer
Assess a number of CNS and non-CNS penetrating chemotherapeutics with and without the Cerense™technology in in vivo model of brain cancer
Explore a range of future applications for this technology in critical care medicine
Year 1 and 2
Based on bibliography candidate lipids were selected.
Taking into account the required radiolabelling steps 2 different lipids were initially formulated by TEIA and sent to UoB for liposome formulation.
Methodology for synthesis of the lipids and liposomes.
DSPC, Chol, PEG-DSPE and DSPE-PEG2000-COOH (for LP-COOH) or DSPE-PEG2000-PEC-2 (for LP-PEC) were dissolved in 2/1 chloroform/methanol in a molar ratio of 51.9: 44.9: 1.7: 1.5, resulting in >3mol% PEGylated lipids
D. Chelation Method C. “After-Loading” or Remote Labeling Method
Laverman et al. Methods In Enzymology, Vol. 373, 2003
Our aim is:
Schematic presentation of the direct or membrane labelling approach for preparing radioactive 99mTc-LP-COOH
Schematic representation of the surface chelation approach for preparing radioactive 99mTc-(CO)3-LP-PEC
Planar static bone imaging with Tc99m-MDP and dynamic study with a Tc99m-Bombesin derivative
Tomographic SPECT system
99mTc-NBRh1 - Dynamic Study
Dynamic image up to 70min p.i
Comparative study of organ uptake for the two 99mTc labelled liposomes in normal Swiss mice at time intervals of 5, 60 min and 24h. Biodistribution values represent the mean±st_dev of %ID/organ (3 animals per time point).
Scintigraphic images (left) at 10min p.i. (one short 2min frame), (center) at ~1h p.i. (sum of all images from 10min to 52min for LP-COOH and up to 58 min for LP-PEC) and (right) at 24 p.i. of female normal Swiss mice intravenously injected with 3.7 MBq or 100μCi οf the radiolabelled LP-COOH (A) and 0.37-0.74 MBq or 10-20 μCi LP-PEC (B)
Biodistribution study of organ uptake for (A) 99mTc LP-COOH (B) 99mTc(I)-(CO)3-LP-PEC in tumour bearing mice at 60 min p.i.. Biodistribution values represent the mean±st_dev of %ID/organ (3 animals were used per time point).
Sum of all scintigraphic images from 10min to 56min for (left) 99mTc-LP-COOH and (right) 99mTc(I)-(CO)3-LP-PEC of tumour bearing mice intravenously injected with 3.7 MBq or 100μCi οf 99mTc-LP-COOH and 0.37MBq or 10 μCi of 99mTc(I)-(CO)3-LP-PEC.
Comparison of image contrast of 99mTc labelledliposomes (LP-PEC & G-LP-PEC) and 99mTc-HMPAO at 1h p.i. (as sum of all images from 10min to 60min) in female normal Swiss mice by a custom high resolution SPECT system (1.5mm spatial resolution).
Two alternative radiolabelling methods have been established, with the chelator method providing more stable complexes, but requiring purification process, which decreases sensitivity.
Planar SPECT imaging can provide spatiotemporal information on lipids biodistribution, which is comparable to ex vivo analysis; higher overall system resolution is expected to improve quantification
In vivo imaging, as well as biodistribution data have confirmed passive targeting on U87MG tumors; those liposomes can be the reference systems for assessing drug delivery to BBB.
Chemical formula and the characteristics of a glucose modified lipid
Training and Networking
During the first year of the project few results were available, thus the project was mainly mentioned in invited lectures and courses
During the second year the project outcomes resulted to a goo number of dissemination activities in scientific and broader audience
The project website contains all major project information and will now move from the teiath.gr domain to www.onconanobbb.eu