Platelet scattering will help in the treatment of cardiovascular disease
Scientists from the I. Kant Baltic Federal University using Raman spectroscopy examined the platelets of patients suffering from cardiovascular diseases and compared them with the spectra of healthy people’s cells. Researchers identified informative spectral regions and showed the promise of studying human platelets using Raman spectroscopy to diagnose diseases associated with changes in the activity of these cells and predict the effectiveness of antithrombotic therapy.
The study was supported by a grant from the Russian Science Foundation. The results are presented at several conferences on optics and medicine: Optics in Health Care and Biomedical Optics IX, October 20–23, 2019, Hangzhou, China and the 6th Annual European Congress on Clinical and Translational Medicine. October 18-20, 2019 Vienna, Austria, and also published in the SPIE Digital Library and the European Journal of Molecular & Clinical Medicine.
Blood consists of a liquid medium – plasma – and cells suspended in it, performing various functions. Platelets play an important role in protecting the body from blood loss during wounds. They are produced by the red bone marrow and, to a first approximation, are colorless oblate spheroids 2-4 micrometers in diameter. Most of the time, these cells are in the blood in a deactivated state, however, when the walls of the vessels are damaged, the products of cell destruction and peculiar molecular “distress signals” get into the blood. Their interaction with proteins on the surface of platelets causes activation of the latter – a quick and, as a rule, irreversible transition to a new state in which cells change their shape. Activation allows them to increase surface area, platelets acquire the ability to adhere to each other (aggregation) and to the walls of blood vessels (adhesion). So at the site of damage a thrombus is formed – a clot that prevents significant blood loss. In addition, platelets secrete special molecules in the tissue, the so-called growth factor, causing cells to divide more actively at the sites of damage.
With the development of some cardiovascular diseases, blood properties change, and blood clots (blood clots) form without damage. Blood clots can circulate through the vessels and adhere to their walls, narrowing the lumen and “catching” new shaped elements. This leads to blockage of blood vessels and impaired blood flow to tissues, which disrupts their function, up to necrosis with a prolonged lack of oxygen and nutrients. A blood clot can clog an artery in the heart (heart attack) or brain (stroke), which leads to serious health consequences and even death. When diagnosing such diseases, several indicators of blood are evaluated, including the number and condition of platelets. The technique is quite laborious and takes a long time, as it requires a series of reactions.
Scientists from the I. Kant Baltic Federal University have proposed using Raman spectroscopy to diagnose platelet status. When using this method, the laser beam is passed through the test substance, and the characteristics of the light scattered by the sample are compared with the initial ones. As a result, the beam intensity at all frequencies is presented in the form of a graph in which scattering peaks are distinguished.
“Raman spectroscopy is being actively studied as a new diagnostic method in various fields of medicine. For example, using this method, it is possible to identify previously studied markers of cardiovascular diseases, as well as to search for new ones. The study of platelets and their aggregation ability can become a new minimally invasive and effective diagnostic method in modern cardiology, ”said Ekaterina Moiseeva, a postgraduate student at the KFU Medical Institute named after I. Kant.
The study involved volunteers, some of whom had no problems with the cardiovascular system, and some suffered from hypertension or suffered myocardial infarction and took antiplatelet agents – blood thinners. Fresh venous blood samples were taken from people from both groups, platelets were isolated from it, and placed on a substrate. The researchers took the spectra of single cells in suspension and studied their features. Comparison of the results of samples from sick people with the results from healthy people showed the difference in the shape of the spectrum in some areas. In patients suffering from cardiovascular diseases, the signal intensity changed, which may be due to a distortion of the physical characteristics of the lipid base of the platelet membrane. “It is too early to talk about the rules by which spectral changes occur. Further studies will allow them to be classified and compared with specific cellular processes, ”said a senior researcher at the Fundamental and Applied Photonics Research and Education Center.