The success and quality of large-scale epidemiological studies depends entirely on biomaterial quality. Therefore, when arranging the third Epidemiology of Cardiovascular Diseases and their Risk Factors in Regions of Russian Federation (ESSE-RF-3) study, increased attention was paid to specifics of collection, processing and further transportation of biological samples and related clinical and anthropometric data of participants from regional collection centers to Biobank.Aim. To develop a methodology for collection of high-quality biomaterials within the large-scale epidemiological study, involving the sampling, processing, freezing of blood and its derivatives (serum, plasma) in the regions, followed by transportation and storage of obtained biomaterial in the Biobank of National Medical Research Center for Therapy and Preventive Medicine (Moscow).Material and methods. To conduct the ESSE-RF-3 study, a design was developed, according to which the collection of venous blood samples in a total volume of 29,5 ml from each participant is planned in all participating regions in order to obtain and store samples of whole blood, serum and two types of plasma.Results. On the basis of international biobanking standards, ethical norms, experience from ESSE-RF and ESSE-RF-2, and literature data, a protocol for biobanking of blood and its derivatives was developed. The type and number of serum and plasma aliquots obtained, the required standard technical means and consumables, as well as logistic biomaterial requirements were determined. Training programs for regional participants were developed. By the beginning of August 2021, 180 thousand samples of whole blood, serum and plasma from more than 23 thousand participants from 28 Russian regions were collected, processed and stored.Conclusion. The presented work made it possible to assess and confirm the compliance of developed biobanking protocol with quality requirements. However, due to the coronavirus disease 2019 pandemic, by August 2021, the Biobank did not reach the maximum effectiveness predicted for the ESSE-RF-3 project.

Aim. To study the effect of standard serum long-term storage at -70О C and with a single thawing on the biochemical markers by comparing the results of studies carried out in 2013-2014 and 2020.Material and methods. The material was the blood serum of participants in the ESSE-RF study, which was stored in a specialized biobank from 2013-2014 at -70О C either continuously (n=149) or with a single thawing (n=20). Initially and in 2020, the quantitative determination of serum biochemical parameters was carried out using same equipment and standard techniques.Results. Long-term storage at -70О C led to mild, but significant changes in almost all analyzed parameters: low density lipoprotein cholesterol (LDL-C) and apolipoprotein A1 levels decreased; levels of highdensity lipoprotein cholesterol (HDL-C), triglycerides, apolipoprotein B, glucose, and high-sensitivity C-reactive protein increased. Insulin and thyroid-stimulating hormone levels did not change during storage. The revealed strong positive relationships between the initial concentrations and those measured in 2020 in samples that were stored continuously indicate the relevance of such storage. In samples with single thawing, changes in most parameters were more pronounced.Conclusion. The results of a prospective cohort study aimed at studying the stability of human serum samples during storage indicate the validity of long-term storage at -70О C without thawing. Freeze-thawing cycle of samples (even once) is unacceptable, since it leads to a pronounced LDL-C decrease. Given the fact that it is the LDL-C levels that is the target of lipid-lowering therapy, continuous low-temperature (not >-70О C) storage of blood serum samples is recommended.

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Aim. To study the effect of the shelf life of frozen whole blood samples in a biobank on the amount of released deoxyribonucleic acid (DNA).Material and methods. The study included whole blood samples placed in tubes with the anticoagulant EDTA (ethylenediaminetetraacetic acid at a concentration of 1,8 mg/ml) from participants in the epidemiological study ESSE-RF-1 and ESSE-RF-2 and cohort studies conducted at the National Medical Research Center for Therapy and Preventive Medicine. The samples were stored in the biobank of the National Medical Research Center for Therapy and Preventive Medicine at temperature from -22О C to -32О C. The shelf life from blood collection to DNA extraction ranged from several weeks to 11 years. DNA was extracted using QIAamp DNA Blood Mini Kit (250) and 96 Blood Kit (Qiagen, Germany). Statistical analysis was performed using the R 3.6.1 software. To analyze the association of blood storage time with the logarithm of DNA concentration, a linear regression was used.Results. The analysis included data on the DNA concentration of 5405 samples. Multivariate regression showed that the blood shelf life was significantly associated with a decrease in concentration by 3,92% (3,16-4,68) for each year of storage (p <0,0001). For 509 samples, the DNA concentration was measured twice, immediately after isolation and after 4,5 years of DNA storage at -32О C. During storage, the concentration of DNA increased by an average of 2% (p=0,046).Conclusion. Long-term storage of whole blood samples at temperature from -22О C to -32О C is associated with a decrease in the DNA yield. Long-term storage of the isolated DNA at a temperature of -32О C is not associated with a decrease in its concentration.

The advances of biomedicine include the new technologies, diagnosis and treatment techniques, as well as the practical use of new types of biological targets, in particular, nucleic acids. Genomic deoxyribonucleic acid (DNA), extracellular DNA (exDNA) and microbiome DNA obtained from different types of samples (tissues, blood and its derivatives, feces, etc.) are used as objects of genetic research. The use of new technologies for DNA analysis required the development of standardized methods for processing biological samples in order to obtain high-quality DNA samples. The research uses various methods for collecting, preparing samples and storing various DNA-containing biomaterials and isolated DNA, as well as methods for assessing the quality of samples and biobank standards. It is obvious that the use of uniform standards will allow large-scale genetic research on the basis of biobanks and research laboratories. Specialists from professional organizations such as International Society for Biological and Environmental Repositories (ISBER), Biobanking and BioMolecular Resources Research Infrastructure-European Research Infrastructure Consortium (BBMRI-ERIC), European, Middle Eastern & African Society for Biopreservationa and Biobanking (ESBB) and the Russian National Association of Biobanks and Biobanking Professionals.