Yulia B. Basok

A comprehensive assessment of allograft quality is essential for predicting successful transplantation and graft survival. Elevated levels of flavin mononucleotide (FMN) in perfusate obtained during hypothermic oxygenated perfusion (HOPE) may serve as a promising predictor of early graft dysfunction and post-transplant complications. The aim of this study was to evaluate the feasibility of applying an FMN determination method to HTK-based perfusion solutions used during liver machine perfusion. The spectrofluorimetric method for FMN determination in modified HTK perfusion solution (modHTK) was evaluated for the following parameters: linearity, accuracy, repeatability, reproducibility, and stability. The study demonstrated the suitability of the quantitative FMN determination method for modHTK solution used during HOPE of liver grafts.

Liver fibrosis is a severe but common disease without an easy-to-access option for efficient treatment. Mesenchymal stem cells (MSCs) of different origins have been tested for antifibrotic effects in vitro, in vivo, and in clinical studies over the two last decades, although the comparative efficiency of different subtypes remains not fully understood, especially for long-term survival. In this study, we aimed to compare the long-time persistence of favorable effects in male Wistar rats with liver fibrosis treated using MSCs derived from white adipose tissue (AdMSCs) and bone marrow (BMSCs). Liver fibrosis was induced by carbon tetrachloride. We studied the survival rate; oxidative index, assessed via laser Doppler flowmetry; hepatic markers in blood plasma—albumin, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase; the ratio of liver to body mass; histological parameters—the number of adipocytes, lymphocytes, siderophages, and Ki67⁺ cells; and the relative areas of connective tissue proper and reticular fibers. Extra mortality was only typical for fibrotic animals subjected to the sham treatment in the first two weeks. Up to Day 270 of this study, both MSC-treated groups showed barely any differences from animals undergoing the sham treatment in terms of the oxidative index and blood markers, although AdMSC-treated rats presented a more favorable histological pattern than BMSC-treated ones, considering the relative area of reticular fibers and the Ki67 cell count. This study suggests that AdMSC treatments may be more appropriate than BMSC treatments in animal liver fibrosis models, with the results showing better potential for liver tissue regeneration 9 months after treatment.

The growing number of patients with severe organ diseases, along with the increasing demand for retransplantations, has intensified the global shortage of donor organs – the primary limitation to expanding transplant programs. Advances in genetic engineering and cell therapy technologies are opening new opportunities for the use of animal organs in human transplantation. Enhancing the effi cacy and safety of this approach requires overcoming signifi cant immunological and physiological barriers inherent in xenotransplantation. This review summarizes recent progress in genetic modification of donor animals, use of cell-based therapy in xenotransplantation, and prospects for clinical application.

Bioabsorbable scaffolds from synthetic polyesters are widely used in the field of tissue engineering. However, their hydrophobic surface and lack of suitable functional groups are the main limitations related to cell attachment. The aim of this research was to modify the surface of polycaprolactone (PCL) scaffolds using a bioactive coating containing heparin bound via albumin spacer and platelet lysate over heparin. Porous scaffolds were produced by electrospinning from 10% PCL (w/w) solution in methylene chloride (25 kV voltage, 100 mm distance between electrodes and 4 mL/h feedrate), which demonstrated 5.5 ± 1.1 MPa Young’s modulus, 2.5 ± 0.4 MPa tensile strength and 321 ± 29% elongation at break. Bioactive coating does not change the structure and mechanical properties of the scaffolds. Treated scaffolds are biocompatible and have no cytotoxic effect in direct contact with cells. Functionalization also promotes the in vitro adhesion and proliferation of human adipose mesenchymal stromal cells. After 7 days of incubation, the PCL scaffold modified with the heparin–platelet lysate complex had a cell density of 185.6 ± 15.7 cells/mm² compared to 79.5 ± 7.8 cells/mm² for nontreated control. The intramuscular implantation of scaffolds revealed that immobilization of heparin alone prolongs the acute phase of the inflammatory reaction. However, subsequent treatment with platelet lysate minimizes the inflammatory reaction, slows the rate of implant absorption, and accelerates vascularization. The results obtained show that the developed bioactive coating improves the cellular properties of PCL electrospun scaffolds and can be used to form in vivo tissue-engineered constructs.

The degeneration of cartilage in articular joints is a significant medical concern due to its high incidence rate. Damaged articular cartilage has a limited ability to regenerate naturally and thus often requires regenerative therapy. Intra-articular matrix-associated autologous chondrocyte transplantation, which involves the introduction of chondrocytes into the damaged area either as part of tissue-engineered constructs with a carrier matrix (scaffold) or in the form of tissue spheroids (chondrospheres), is generally considered the gold standard for treating such defects. This approach is probably the most biomimetic restorative articular cartilage treatment in the sense that it supports the cells in spheroids to produce and accumulate their own extracellular matrix. The growing interest in large-scale production of such biomedical cellular products raises the question of accessible and effective methods for assessing the quality of obtained chondrospheres, both in terms of their chemical composition and biological properties. Here, a sensor prototype based on comparative electrochemical profiling of chondrospheres is proposed for quantitative assessment of the accumulation of extracellular matrix components in hyaline cartilage.

A two-layer bioresorbable vascular graft (BVG) with an internal diameter of 2 mm has been developed from biopolymer bioresorbable materials: synthetic polymer polycaprolactone and high-molecular compound of natural origin—gelatin. BVG has a highly porous structure, physical and mechanical characteristics close to a natural blood vessel of a similar diameter, and water permeability of less than 10 mL/(cm² min). The graft is biocompatible and, when implanted into the infrarenal aorta of a rat, demonstrates blood flow parameters (systolic and diastolic velocity and resistivity index) close to the corresponding parameters of the rat aorta. Under in vivo functioning conditions, the two-layer vascular graft is resistant to stratification and does not provoke an inflammatory reaction, and after 8 weeks of functioning, the formation of neointima is observed on the inner surface of the BVG against the background of the integration of the graft into the body’s surrounding tissues.

Organ transplantation continues to be the gold standard for saving the lives of patients with end-stage organ diseases. Its goal is to help recipients live longer and better lives. However, despite advancements, organ transplantation still faces serious challenges, such as organ shortage and the effects of chronic immunosuppression. In this regard, there is ongoing vigorous search for therapeutic strategies that can improve the efficacy of allogeneic organ transplantation. Mesenchymal stems cells (MSCs) can significantly enhance and accelerate regenerative processes in damaged organs, can angiogenesis angiogenesis and inhibit cell apoptosis, inflammation and fibrosis formation, and have immunomodulatory properties. Researchers and physicians are interested in MSCs because of a set of unique properties that could be useful in solid organ transplantation. This review critically analyzes and summarizes the actual clinical data related to the study of the therapeutic effects of MSCs in organ transplantation. Electronic databases Medline/PubMed (www/ncbi.nlm.nih.gov/pubmed) and eLIBRARY/Russian Science Citation Index (https://www.elibrary.ru) were searched for relevant literature. Inclusion criteria were clinical use of MSCs to improve the condition of kidney, liver, lung, heart and pancreas recipients, and to enhance graft quality. Exclusion criteria for articles included the use of MSCs for the treatment of non-transplant patients, as well as articles detailing the effects of MSCs products (exosomes, vesicles and conditioned media) and research studies conducted in vitro and in vivo (without patient participation), conference proceedings, reviews and preprints of articles. Thirty-one original articles in English and Russian languages were selected for literature review. The prospects of MSCs in transplantology are also covered in the paper.

Producing a tissue-engineered pancreas based on a tissue-specific scaffold from a decellularized pancreas, imitating the natural pancreatic tissue microenvironment and the islets of Langerhans, is one of the approaches to treating patients with type 1 diabetes mellitus (T1DM). The aim of this work was to investigate the ability of a fine-dispersed tissue-specific scaffold (DP scaffold) from decellularized human pancreas fragments to support the islets’ survival and insulin-producing function when injected in a streptozotocin-induced diabetic rat model. The developed decellularization protocol allows us to obtain a scaffold with a low DNA content (33 [26; 38] ng/mg of tissue, p < 0.05) and with the preservation of GAGs (0.92 [0.84; 1.16] µg/mg, p < 0.05) and fibrillar collagen (273.7 [241.2; 303.0] µg/mg, p < 0.05). Rat islets of Langerhans were seeded in the obtained scaffolds. The rats with stable T1DM were treated by intraperitoneal injections of rat islets alone and islets seeded on the DP scaffold. The blood glucose level was determined for 10 weeks with a histological examination of experimental animals’ pancreas. A more pronounced decrease in the recipient rats’ glycemia was detected after comparing the islets seeded on the DP scaffold with the control injection (by 71.4% and 51.2%, respectively). It has been shown that the DP scaffold facilitates a longer survival and the efficient function of pancreatic islets in vivo and can be used to engineer a pancreas.

The progressive development of diabetes mellitus (DM2) in db/db mice is associated with three stages of impaired carbohydrate metabolism and redox processes. In db/db mice, the content of erythrocytes, hemoglobin, and leukocytes was found to decrease already in stage I of DM2. In the II and, in particular, III stages, an increase in platelets, percentage of neutrophils, monocytes, and eosinophils was observed, along with a decrease in lymphocytes. In the bone marrow of db/db mice, a decrease in the proportion of living cells and an increase in the number of damaged cells were determined already in stage I, but especially in stage III, mainly due to aponecrotic cells. Therefore, along with the progression of DM2 and a marked decrease in the effectiveness of redox processes, particularly in stage III, hematopoiesis processes are inhibited and disturbances in the ratio of neutrophil/lymphocyte cell populations increase. This indicates the development of severe hypoxia, activation of a systemic inflammatory reaction, and inhibition of reparative processes that create conditions for the development of dangerous complications.

The umbilical cord is a material that enhances regeneration and is devoid of age-related changes in the extracellular matrix (ECM). The aim of this work was to develop a biodegradable scaffold from a decellularized human umbilical cord (UC-scaffold) to heal full-thickness wounds. Decellularization was performed with 0.05% sodium dodecyl sulfate solution. The UC-scaffold was studied using morphological analysis methods. The composition of the UC-scaffold was studied using immunoblotting and Fourier transform infrared spectroscopy. The adhesion and proliferation of mesenchymal stromal cells were investigated using the LIVE/DEAD assay. The local reaction was determined by subcutaneous implantation in mice (n = 60). A model of a full-thickness skin wound in mice (n = 64) was used to assess the biological activity of the UC-scaffold. The proposed decellularization method showed its effectiveness in the umbilical cord, as it removed cells and retained a porous structure, type I and type IV collagen, TGF-β3, VEGF, and fibronectin in the ECM. The biodegradation of the UC-scaffold in the presence of collagenase, its stability during incubation in hyaluronidase solution, and its ability to swell by 1617 ± 120% were demonstrated. Subcutaneous scaffold implantation in mice showed gradual resorption of the product in vivo without the formation of a dense connective tissue capsule. Epithelialization of the wound occurred completely in contrast to the controls. All of these data suggest a potential for the use of the UC-scaffold.