GC-08. Study of the biodistribution of polymer carriers for further use in gene therapy
Anna S. Rogova1, Anastasia S. Bukreeva1, Alisa S. Postovalova1, Darya R. Akhmetova1, Alexander S. Timin1,2, Albert R. Muslimov1,2
1 Peter The Great St. Petersburg Polytechnic University, St. Petersburg, Russia
2 Pavlov University, St. Petersburg, Russia
Anna S. Rogova, phone: +7 (904) 601-79-55, e-mail: firstname.lastname@example.org
Various methods of gene therapy demonstrate great prospects in the treatment of various hereditary, infectious and oncological diseases. However, now, the effectiveness of their use is limited by the lack of effective and safe methods of delivering genetic material to cells. To solve this problem, a method consisting in the delivery of genetic material using polymer particles can be used. One of the important advantages of this method is the structure of the capsule, which allows it to protect the contents from the aggressive effects of biological environments of the body. However, for further use of these carriers in clinical practice, it is necessary to study in detail their bio-distribution after introduction into the body. The purpose of this work is to study the bio-distribution of polymer particles on mouse model by various methods, as well as histopathological analysis of tissues after the introduction of carriers.
Materials and methods
In this work, polymer particles obtained by applying polyarginine and dextran sulfate (PARG/DEXS) using Layer-by-Layer technology to calcium carbonate nuclei were used. The nuclei were obtained by co-precipitation of aqueous solutions of salts: sodium carbonate and calcium chloride with the addition of fluorescent dyes FITC and Cy5, as well as magnetite particles. The synthesized carriers were evaluated by light and confocal microscopy, as well as dynamic light scattering. Then the particles were injected into the tail vein of the mice, after which their organs (heart, lungs, liver, spleen and kidneys) were analyzed on the IVIS Spectrum CT device for in vivo fluorescence imaging on days 2, 5, 7, 10 and 15. The data of histological sections were also obtained using imaging methods on a confocal laser scanning microscope (CLSM) and a light microscope.
The results obtained by the methods of CLSM (particles labeled with FITC), light microscopy (labeled with magnetite) and IVIS bioluminograph (labeled with Cy5) correlate with each other, but the assessment of biodistribution using particles labeled with magnetite is not optimal due to the characteristics of the liver and spleen tissue. After administration, the particles are found in large quantities in the lungs, presumably due to the small size of the capillaries and in the liver. Then there is a general decrease in the number of particles in the organs. On day 10, the number of particles in the lungs becomes minimal, while a sufficient amount is recorded in the liver. Also, on days 10 and 15, particles were registered in the spleen. Histopathological analysis illustrates the absence of pathological changes when using polymer micron particles. There is a significant accumulation of particles in tissues with a highly developed reticuloendothelial system (liver, spleen and lungs).
The presented data allow us to better understand the distribution of particles in the animal’s body over a long time and provide information about which organs can potentially be delivered therapeutic agents using this delivery system. In the future, it is planned to conduct experiments on the delivery of clinically relevant genetic material in vivo.
The work was carried out with the support of the project of the Russian Science Foundation “19-75-10010”.
Polymer carriers, delivery of genetic material, bio-distribution, histological examination, in vivo visualization.