We herein present our initial report from «ROKKOR-recipient», a national multicenter observational study. The prevalence, risk factors, clinical manifestations and outcomes of the novel coronavirus disease 2019 (COVID-19) in solid organ transplant recipients receiving immunosuppressive therapy were investigated. The study enrolled 251 COVID-19 patients (220 kidney recipients, 7 liver recipients, 1 liver-kidney recipient, and 23 heart recipients). The subjects came from 20 regions in Russia. The symptoms, clinical presentation, imaging and lab test results, therapy and outcomes of COVID-19 were described. It was established that solid organ transplant recipients with COVID-19 have a higher risk of developing adverse events. Predictors of adverse events include associated cardiovascular diseases, pulmonary diseases, diabetes, and kidney failure. Symptoms of the disease include dyspnea, rash and catarrhal signs, as well as initial low blood oxygen saturation (SpO₂ <92%), leukocytosis (white blood cell count >10 × 10⁹/L), elevated creatinine levels (>130 μmol/L) and a marked decrease in glomerular filtration rate, requiring hemodialysis. Performing organ transplant surgery in COVID-19 does not increase the risk of adverse events but could save the lives of waitlisted terminally ill patients.

Many studies have shown that biliary complications after transplantation of the left lateral segment (LLS) of the liver reduce graft and recipient survival. Thus, timely correction of biliary complications, and strictures in particular, improves long-term outcomes in transplantation. Objective: to analyze our own experience in correcting biliary strictures in LLS graft transplantation. Materials and methods. From February 2014 to April 2020, 425 LLS grafts were transplanted in children. 19 (4.5%) patients were diagnosed with biliary strictures at different times after transplantation (from 0.2 to 97 months). Results. Biliary strictures were more often formed a year after transplantation (17.8 ± 23.9 months). In 14 out of the 19 patients, internal-external biliary drainage was successfully performed with phased replacement of the catheter with one that was larger in diameter (from 8.5 Fr to 14 Fr). The catheters were removed in 8 patients after completion of the treatment cycle. Restenosis was not observed during follow-up (13 ± 8.7 months) after the internal-external biliary drainage catheter had been removed. In 5 cases, antegrade passage of a guide wire through the stricture was unsuccessful. As a result, biliary reconstruction was performed in 4 (21.1%) patients and retransplantation was required in 1 (5.3%) patient. Conclusion. An antegrade minimally invasive approach can successfully eliminate biliary strictures in most children after liver LLS graft transplantation. The proposed technique is effective and safe.

Objective: to determine the threshold MELD scores when prioritizing for liver transplantation. Materials and methods. We conducted a cohort study of 350 patients who were waitlisted for liver transplantation between 2015 and 2020. Results. A logistic regression model was used to identify the independent predictors of liver transplantation waitlist mortality. MELD scores and serum albumin at the time of listing were significant predictors of mortality (p = 0.001 and p = 0.004, respectively). Their predictive values were confirmed using ROC (Receiver Operating Characteristic) analysis. The area under the ROC curve (AUC) was 0.883 [95% confidence interval (CI) 0.828–0.939; p < 0.001] for MELD, and 0.841 [95% CI 0.775–0.907; p < 0.001] for serum albumin. Mortality odds ratio was 3.7778, 95% CI (1.619–7.765) provided that the listing MELD score was ≥25. Mortality odds ratio was 2.979 (95% CI 1.63–5.95) provided that the listing serum albumin concentration was ≤30.1 g/L. With a threshold MELD score of 25, there were significant differences between patient survival when comparing patient cohorts with MELD ≥25 and with MELD ≤25 (Log-rank, p < 0.0001). Conclusion. The MELD model has a high predictive ability in prioritization of waitlisted candidates for liver transplantation. The threshold MELD score and mortality predictors were determined. There were significant differences between patient survival among patient cohorts with MELD ≥25 and with MELD ≤25.

Liver transplantation is the only effective treatment modality for end-stage liver disease. However, donor organs are not always available. In some cases, the gravity of the patient’s condition makes transplantation impossible. In this regard, the use of artificial liver support systems helps in preparing a patient for transplant surgery. Objective: to conduct a retrospective study aimed at evaluating the efficiency of fractionated plasma separation and adsorption system. Materials and methods. From January 2019 to May 2020, 139 pediatric liver transplants were. We analyzed the data of 5 pediatric patients (2 girls and 3 boys, aged 12 to 17 years) who received fractionated plasma separation and adsorption (FPSA) sessions as a bridge to transplantation. The main clinical indication for FPSA was severe hepatic encephalopathy (grade 3 according to the West Haven Criteria), which was observed at 350–872 μmol/L (average 597 ± 98 μmol/L) serum bilirubin level. The FPSA sessions were conducted on a Prometheus device using AV-600 hemofilters as dialyzers (Fresenius Medical Care, Germany). Results. Depending on the extent of bilirubinemia in patients, it took from one (in one case) to three (in one case) daily FPSA sessions to restore clear consciousness, appetite and physical activity. Average bilirubin levels after treatment cycles decreased from 597 ± 98 to 236 ± 73 μmol/L. All patients successfully underwent liver transplant surgery within two to five days, two patients received a liver fragment from a living related donor. Conclusion. The FPSA system stabilizes the condition of potential recipients with acute liver failure. Further research is required to develop optimal regimens for albumin dialysis.

Organ donation and transplantation in Moscow have witnessed changes in the last decade. These changes have led not only to quantitative growth in the number of effective donors but also to fundamentally new (for Russian medical practice) characteristics of the donor pool. As a result, the selection criteria for organ donors have undergone some radical revisions. Objective: to analyze the medical and epidemiological characteristics of the pool of effective heart donors and assess their impact on selection of heart transplants. Materials and methods. In our study, we used the medical and epidemiological data of 650 brain-dead donors whose organs were procured from January 1, 2012 to December 31, 2017. Results. During the study period, the number of effective heart donors in Moscow increased from 4.4 (2012) to 11.2 (2017) per million population per year. The medical and epidemiological characteristics of the total pool of donors and the pool of heart donors underwent major changes. Among effective heart donors, there was a dynamic increase in the average age from 38.4 to 47 years, predominance of a proportion of donors with stroke 38.2 (2012) vs 83.2 (2017) and, accordingly, an increase in the frequency of such comorbid conditions, as hypertension and diabetes. Conclusion. The results presented in the study indicate a growing practice of working with expanded criteria donors. This practice is most effectively developed in the field of heart transplantation than in transplantation of other extrarenal organs. Undoubtedly, the experience under study is unique and relevant not only for the Russian Federation, but also for the world of transplantology, as it allows to provide vital assistance to patients with end-stage heart failure within a reasonable timeframe.

Objective: to assess the functional state of the cardiorespiratory system in the long term after orthotopic heart transplantation (HT) with prolonged cold ischemia time. Materials and methods. The results of 60 orthotopic HTs performed at Meshalkin National Medical Research Center were analyzed. A comparison was made of the immediate and long-term outcomes of HTs in the group with cold ischemia time lasting for less than 240 minutes and in those with farther distance between donor and recipient sites with cold ischemia time of 240 minutes or more. In the long-term follow-up after HT, all patients underwent cardiopulmonary exercise testing, body plethysmography, assessment of the diffusing capacity of the lungs, and quality of life assessment. Results. Prolonged cold ischemia showed a negative effect on the early postoperative period – decreased myocardial contractility on postoperative day 1 and longer duration of inotropic support. At the same time, the survival rate and incidence of graft rejection reactions in the early and late post-HT periods in the studied groups did not differ significantly. Peak oxygen consumption in the general group in the long term after HT was 17 (14.7–21.0) mL/kg/min, VE/ VCO₂ slope was 30 (29–36) at 100 (90–120) W threshold load power. All the parameters of pulmonary function tests did not differ significantly depending on cold ischemia duration. Quality of life also did not show significant differences depending on the duration of graft ischemia in terms of both physical and psycho-emotional health components of the SF-36 questionnaire. Conclusion. Long-term cold ischemia of the graft did not show any negative impact on the functional state of the cardiorespiratory system and quality of life in the long term after HT. The studied group of recipients was characterized by high efficiency of pulmonary ventilation and gas exchange, as well as high tolerance to physical activity in the long-term post-HT period.

Objective: to assess the personal psychological profile of heart transplant recipients as the first stage in the development of post-transplant personalized rehabilitation programs. Materials and methods. From January 2010 to July 2019, 129 HTs were performed (mean age 46.6 ± 14.1 years; 74% (n = 95) were men, 26% (n = 34) were women). All patients in the heart transplant waiting list were examined by a clinical psychologist and a psychotherapist to exclude contraindications to transplant surgery. To assess personal traits, we used the standard multifactorial questionnaire by Cattell R., 16 PF (version A), which included 187 questions. Heart transplantation and absence of post-transplant severe cognitive impairments were the selection criteria for this study. Patients were surveyed before they were discharged from the hospital – 30–60 days following HT: during the period of complete recovery after surgery. In the present study, a retrospective assessment of the results was performed in 107 patients (n = 76 – men; n = 31 – women). Results. Analysis of the personality portrait revealed that over half of recipients were reserved, distant (factor A – schizothymia) and restrained (factor F – restraint; F2 – introvert; F4 – conforming) with lower mental capacity (factor B), and were shy, timid (factor H), with low super ego (factor G: irresponsible, tolerates disorder, flexible, open to change). Our results showed that 47% of patients (n = 18 out of 38 patients, n = 22 are pensioners) with a weak degree of factor C (reactive, affected by feelings) are workers to 42% (n = 29 out of 69, n = 28 – retirees) with a strong degree of the same factor. One year after HT, the number of physically active patients was higher among those with low anxiety compared with high anxiety (41% (18 of 44) and 32% (20 of 63), respectively, p = 0.41). Conclusion. Personality factors are non-modifiable characteristics of patients. They affect human behavior, return to work and to social life, as well as physical and psychological recovery from HT. Knowing the personal traits of recipients would allow to develop a personalized approach to their rehabilitation and a technique for timely examination after HT.

Objective: to analyze the correlation between the expression levels of microRNA-101, microRNA-142, microRNA-27, microRNA-339, and microRNA-424 and the plasma concentrations of biomarkers that are potentially significant for the diagnosis of post-transplant complications in heart recipients. Materials and methods. The study enrolled 72 heart recipients, among whom were 56 men (77.8%). The average age of recipients was 48.6 ± 10.9 (16 to 70) years. There were 38 patients with severe chronic heart failure, among whom were 29 men (76.3%). Patients’ mean age was 48.8 ± 9.9 (26 to 70) years. The control group consisted of 12 healthy individuals who did not differ significantly by sex and age. microRNA expression levels in blood plasma were measured via quantitative polymerase chain reaction. Plasma concentrations of VEGF-A, PLGF, MCP-1, and sCD40L were determined using a multiplex method. ST2 and Galectin-3 concentrations were measured via enzyme-linked immunosorbent assay. Results. Patients with end-stage chronic heart failure were found to have significantly higher expression levels of microRNA-27, microRNA-339 and microRNA-424 in blood plasma compared with the healthy individuals. In potential heart recipients, the expression le vels of microRNA-339 and microRNA-424 correlated with serum galectin-3 concentrations, microRNA-101 expression levels correlated with PLGF-1 concentrations, while microRNA-27 expression levels correlated with plasma MCP-1 concentrations. In the early post-transplant period, the expression levels of microRNA-101, microRNA-339, and microRNA-424 in heart recipients were significantly lower than in patients with severe chronic heart failure. In the early post-transplant period (one year or more after transplantation), microRNA-101 and microRNA-27 expression levels were significantly higher than in heart recipients. A year or more after transplantation, the following correlations were found in heart recipients: microRNA-142 expression level correlated with serum levels of galectin-3 (p = 0.05), microRNA-27 and microRNA-424 expression levels correlated with ST2 concentrations (p = 0.02), microRNA-27 expression level correlated with PLGF-1 concentrations (p = 0.02), while microRNA-101 expression level correlated with serum levels of PAPP-A (p = 0.05). Conclusion. In heart recipients, the expression levels of microRNA-142, microRNA-27, microRNA-424, and microRNA-101 correlate with the concentration levels of biomarkers of fibrosis (Galectin-3), rejection (ST2), neoangiogenesis (PLGF), and tissue destruction (PAPP-A). A comprehensive analysis of pre- and post-translational markers may open up new perspectives in diagnosis, assessment of the risks of post-transplant complications, and in understanding the processes leading to their development.

The objective of this work is to conduct research on a mathematical model to assess hemolytic characteristics in a channel centrifugal blood pump developed by us with 2000–3400 rpm impeller speed range and 100–250 mmHg pressure drop in different parts of the pump flow path. Hemolysis index was measured at 1 to 10 L/min flow rate. The result was an estimate of the average magnitude of the shear stress (SS), taking into account the distribution in the pump, which ranged from 40 to 60 Pa. The most critical areas of the pump in terms of blood injury were evaluated. The maximum SSs were determined: 456 Pa in the impeller wheel zone and 533.3 Pa in the adjacent area of the body, with an exposure time of 0.0115 s and 0.0821 s respectively. In these zones, maximum hemolysis index values were 0.0420 and 0.0744 respectively. Based on the data obtained, these zones were optimized in terms of minimizing hemolysis.

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. In order to reduce the number of postoperative complications following open surgeries, a number of clinics in the USA and Europe are currently developing robot-assisted surgical techniques. Studies have shown that robotic surgery facilitates kidney transplantation under optimal ergonomic position for the surgeon, with functional results and patient safety comparable to those obtained under an open approach. We herein present our initial experience (in the Russian Federation) on heterotopic cadaveric kidney transplantation by laparoscopic surgery using the Da Vinci robotic surgical system.

Objective: classical methods of determining arterial blood supply of the graft following orthotopic liver transplantation (OLT) reflect the presence of blood flow in the trunk and large branches of the A. hepatica, without the characteristic of completeness of blood filling of peripheral sections, which is very important for objective evaluation of function. The aim of this study is to establish the diagnostic value of a direct perfusion study (IFlow) of the graft. Materials and methods. From 1998 to 2019, 245 OLTs were conducted. From 2015 to 2019, arterial changes were detected in 24 (23%) patients after 104 OLTs. A perfusion study was performed in 9 patients with suspected arterial graft failure. According to the IFlow study, liver hypoperfusion due to stenosis and/or splenic steal syndrome was detected in 8 cases and became an indication for therapeutic intervention. Results. Hepatic stenting and/or splenic artery embolization was performed to improve arterial blood supply to the liver. Endovascular procedures performed restored the perfusion index from 0.24 (0.01–0.89) to 0.61 (0.35–0.98). Conclusion. Absence of ultrasound and multispiral computed tomography signs of arterial complications does not rule out the need for perfusion angiography. Perfusion angiography allows to objectify the angiography data and perform corrective intervention in good time.

Introduction. We present the clinical observation of a 72-year-old female patient with high surgical risk and structural degeneration of a bioprosthetic aortic valve (AV) cusps in the form of stenosis, accompanied by severe dysfunction. Transcatheter implantation of bioprosthesis Medtronic CoreValve™ Evolut™ R-23 was performed using the valve-in-valve technique. The choice of minimally invasive treatment tactics is substantiated, a preoperative examination algorithm and a specific bioprosthesis model for such intervention are provided. Materials and methods. Imaging – echocardiography (Echo), electrocardiography, multispiral computed tomography, coronary angiography. Bioprosthetic valve calcification and stenosis with critical parameters of the bioprosthetic AV peak pressure gradient according to Echo data were the indications for minimally invasive surgery. Results. Dynamic observation revealed a progressive deterioration in the function of the previously implanted bioprosthetic heart valve in the aortic position, and a critical deterioration in the patient’s condition. After additional examination of the patient and selection of a new prosthesis, valve-in-valve transcatheter aortic valve replacement was done. The positive dynamics of the general state of the patient was noted in the early postoperative period. Echo data showed that the bioprosthetic AV peak systolic pressure gradient decreased from 90 to 29 mmHg, average gradient – from 42 to 19 mmHg. Conclusion. The minimally invasive valve-in-valve transcatheter aortic valve replacement used to correct the dysfunction of a bioprosthetic AV that was previously implanted during an open surgery was shown to be safe and effective and can be considered as one of the options for repeat valve replacement.

Mandibular reconstruction after partial or complete resection is a prerequisite for restoring normal facial aesthetics, articulation and chewing function. We present a clinical case of lower jaw reconstruction in a female patient with acquired extensive bone defect while taking pervitin and desomorphine. Detailed descriptions of the stages of planning and performing surgery, manufacture of an individual endoprosthesis, as well as preoperative preparation of the patient are presented. Clinical and radiological data in the postoperative period were analyzed and an objective assessment of the effectiveness of the technique was given. Adequate restoration of the main functions of the lost organ was achieved thanks to the use of an individual titanium mandibular endoprosthesis with integrated dental implants and a full-arch denture.

Shortage of donor organs for liver transplantation in the treatment of end-stage liver disease dictates the need to develop alternative methods that include technologies on tissue engineering and regenerative medicine. Objective: to study the ability of a tissue-specific matrix from decellularized human liver fragments (DHLF) to maintain adhesion and proliferation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) and HepG2 under static conditions and in a flow-through bioreactor. Materials and methods. Treatment with surfactants (SAS) – sodium dodecyl sulfate, Triton X-100 – followed by exposure to DNase was used for decellularization of human liver fragments (no more than 8 mm³). Biochemical screening included the determination of DNA quantity in the test samples. Efficiency of surfactant washing was assessed by the cytotoxicity of the matrix in the NIH 3T3 fibroblast culture. Viability and metabolic activity of cells were assessed via vital staining with a complex of fluorescent dyes LIVE/DEAD ® and PrestoBlue™ (Invitrogen, USA). Morphological examination of the liver cell-engineered constructs was carried out through histological staining and scanning electron microscopy with lanthanide contrast. Results. It was shown that the liver decellularization method used allows to obtain a biocompatible matrix with a residual DNA quantity <1%, which is capable of maintaining adhesion and proliferation of hAT-MSCs and HepG2. On day 7 of cultivation in the bioreactor, there was formation of a single conglomerate of the DHLF matrix with numerous groups of viable cells with a high nuclear-cytoplasmic ratio. The urea content in the culture medium is 1.5 ± 0.1 mmol/L, exceeding that of samples obtained under static conditions. This indicates the metabolic activity of HepG2 in the composition of the obtained culture systems. It was shown that constant flow of the culture medium in the perfusion bioreactor increased the proliferative activity of HepG2 and allowed to provide a more uniform colonization by matrix cells in comparison with static cultivation conditions. Conclusion. The conditions for uniform colonization of DHLFs in a flow-through bioreactor with cell cultures were established. The ability of the matrix to maintain adhesion and proliferation of hADSCs and HepG2 for 11 days indicates that it could be used in liver tissue engineering.

Objective: to study the cellular mechanisms of activation of regenerative processes in the liver when using total RNA (tRNA) of bone marrow cells (BMCs) based on an extended liver resection (ELR) model. Materials and methods. Male Wistar rats (n = 80) with ELR model (70%) were divided into 2 groups: group 1 (control group) had a single saline injection, while group 2 (experimental group) received a single tRNA injection at a 30 μg/100 g dose of animal weight. The biochemical parameters of liver function and weight were monitored over time. Also monitored were microstructural changes in hepatocytes 48 hours after ELR by examining mitotic activity, caspase-9 expression and morphometric parameters. Results. It was found that in group 2, in comparison to group 1, there was faster normalization of biochemical parameters (by 10–14 days), a higher mitotic index of hepatocytes (23.45‰ versus 5.37‰), and initially sharper decrease and then faster recovery of liver mass (by 10–12 days versus 18–20 days). Both groups showed almost total expression of caspase-9, including in mitotically splitting hepatocytes. Group 1 demonstrated decreased values of morphometric parameters of single and binuclear cells, decreased number of binucleated hepatocytes and increased total density of hepatocytes as compared to the intact liver. Intraperitoneal administration of tRNA increased morphometric parameters of mononuclear hepatocytes, did not affect their number, but increased the area of the nuclei of binuclear hepatocytes as compared to the control group. Conclusion. The proven capability of cell-bone marrow total RNA to simultaneously support apoptosis in liver cells after ELR and induce mitotic activity indicates that tRNA can switch activated apoptosis to cell proliferation at the early phase of the regenerative process. This effect may be due to the presence of regulatory RNA molecules in tRNA, including numerous non-coding RNAs.

Objective: to analyze the 3D micro- and nanostructure and quantitative morphological parameters of rat lung tissue. Materials and methods. Wistar rat lung tissue samples were obtained for the study. The 3D structure of the lung tissue was studied via scanning probe nanotomography using an experimental setup combining an ultramicrotome and a scanning probe microscope. Results. Nanoscale images and 3D nanotomographic reconstructions of the interalveolar septal sections of the rat lung were obtained. Morphological parameters (average roughness and specific effective area) of the interalveolar septal surface were determined. It was found that the average roughness of the reconstructed septal surface was 345.4 ± 24.5 nm, and the specific effective area was 2.7 ± 0.2 units. Conclusions. Results obtained demonstrate that scanning probe nanotomography allows to quantify lung morphology. The use of scanning probe nanotomography for 3D analysis of the structure and characteristics of lung tissue will increase the efficiency of future developments on creation of new criteria for diagnosing pathological conditions.

This paper demonstrates a chemical way of enhancing transdermal delivery using immunomodulator glucosaminylmuramyl dipeptide (GMDP) as an example. Objective: to study in vitro the effect of various components of the microemulsion composition on GMDP diffusion through the skin from a transdermal therapeutic system (TTS). Materials and methods. Medicinal substance – glucosaminylmuramyl dipeptide (Peptek, Russia). Excipients and raw materials: sodium chloride, purified water, sodium dodecyl sulfate, docusate sodium, oak bark, apricot kernel oil, alpha-tocopheryl acetate and Decaglyn PR-20 emulsifier. Equipment: Heidolph DIAX 900 mechanical disperser (Germany) and Hielscher UIS250V ultrasonic homogenizer (Germany). GMDP diffusion from TTS through unpreserved rabbit skin was studied on diffusion tester Copley (UK). GMDP in aqueous solutions was determined by reversed-phase high-performance liquid chromatography (RP-HPLC) on an Agilent 1200 chromatography system (Agilent Technologies, USA). Results. A microemulsion system composed of 20% docusate sodium in an oil phase and an oak bark decoction as an aqueous phase was developed. This made it possible to increase GMDP transdermal delivery by ~70% in comparison with the basic composition. Conclusion. The characteristic parameters of microemulsion components of GMDP contained in TTS, influencing GMDP diffusion through unpreserved rabbit skin in vitro, were determined. Introducing relative indicators would be advisable in order to correctly evaluate the results of different series of in vitro experiments with biological objects.

Scar smoothing out, angiogenesis stimulation and cardiomyogenesis in myocardial infarction still remain pressing issues despite the variety of existing methods. One of the ways to correct them is intramyocardial implantation of an alloplant biomaterial (ABM) suspension. ABM serves as an inhibitor of fibroneogenesis in various tissues with chronic inflammatory processes. No studies have been carried out with regards to acute myocardial infarction. Objective: to assess the dynamics of the number of bFGF-1 + cells and CD68 macrophages, the degree of angiogenesis amidst the use of ABM in the formation of postinfarction scar in the experiment. Materials and methods. Experimental studies were performed on 100 male Wistar rats weighing 0.18–0.25 kg. Coronary artery ligation was performed on all animals. In the experimental group, the ABM suspension (12 mg) was injected intramyocardially. We used histological, electron microscopic, immunohistochemical (CD68, bFGF-1), morphometric and statistical research methods. Hearts were procured at day 3, 7, 14, 30, and 45. Results. The use of an allogeneic biomaterial immediately after coronary artery stenosis could reduce the area of cicatricial myocardial degeneration by two fold by accelerating inflammatory response and the onset of early proliferative phase. In the reactive zone after ABM implantation, macrophage myocardial infiltration significantly decreased in comparison to the control group. The use of ABM ensures significant predominance of bFGF-1⁺ cells in the initial period of inflammation (3–14 days). Subsequently (14–45 days), inflammatory cytokine expression became several times less, which corresponded to biodegradation and resorption of the biomaterial. In the control group, during the acute phase of inflammation (3–14 days), bFGF-1⁺ cells were low in number. Subsequently (14–45 days), cytokine expression increased significantly, causing rapid accumulation of collagen fibers and scarring. In myocardial regeneration after a heart attack in the experiment, ABM stimulated angiogenesis, whose level was three times higher than in the control group. It was noted that ABM serves as a regulator of the neofibrillogenesis-fibroclasia balance in tissue. Conclusion. Macrophage migration inhibition and suppression of pro-inflammatory orientation of macrophages should be indicated as one of the directions of therapeutic correction strategy for ischemic myocardial injuries. Alloplant biomaterial used in the acute phase of myocardial inflammation can serve as such alternative.

Objective: to develop technologies for preoperative preparation of the posterior lamellar corneal graft based on our own formulation of the preservation medium for optimal dehydration of the donor cornea and a technique for cutting out an ultrathin flap using an optimized method at the Eye Tissue Bank. Materials methods. In a series of experimental studies, we obtained data on the hydration level of cadaveric donor corneas that were preserved in various solutions at different observation periods. Using 16 corneas, analytical weighing and pachymetry were performed via optical coherence tomography in the experimental (n = 8) and control (n = 8) groups. Morphological and functional characteristics of the corneal endothelium were then assessed. At the next stage of work, ultrathin grafts were formed from 16 corneas after hypothermic preservation in the experimental (n = 8) and control (n = 8) solutions by single-pass microkeratome, followed by microscopy of the samples using a scanning electron microscope. Results. After the first days of preservation in the proposed solution, there was dehydration of 9% cornea in the experimental group in comparison with the samples of the control group. After 4 days of preservation, there was no reliable difference found between the groups (p > 0.05) in the study of the endothelial cell viability of ultra-thin corneal grafts by immunofluorescent microscopy using the «Live and dead» marker. Scanning electron microscopy revealed that corneal stromal collagen fibers, preserved in the proposed medium, retained their integrity. Conclusion. The proposed technology can be recommended for use at eye banks for formation of an ultra-thin corneal graft at the preoperative stage.

With the limited capacity of the available donor pool and the simultaneously growing demand for heart transplantation, expanding the heart donor selection criteria as one of the ways of increasing the availability of organ transplantation, and particularly donor heart, has become a challenge. On one hand, the use of expanded criteria donors increases the number of transplants and reduces the time spent on the waiting list. On the other hand, however, it increases the risk of adverse transplant outcomes. Accordingly, high-risk donors require a more thorough objective assessment using predictive models, while organs obtained from expanded criteria donors, require optimal selection of a donor-recipient pair. Analysis of global and national studies presented in this review reveals the depth of the current problem of heart donor selection.