Post-Implantation Inflammatory Responses to Xenogeneic Tissue-Engineered Cartilage Implanted in Rabbit Trachea: The Role of Cultured Chondrocytes in the Modification of Inflammation.

Immune responses to tissue-engineered grafts made of xenogeneic materials remain poorly studied. The scope of current investigations is limited by the lack of information on orthotopically implanted grafts. A deeper understanding of these processes is of great importance since innovative surgical approaches include the implantation of xenogeneic decellularized scaffolds seeded by cells. The purpose of our work is to study the immunological features of tracheal repair during the implantation of tissue-engineered constructs based on human xenogeneic scaffolds modified via laser radiation in rabbits. The samples were stained with hematoxylin and Safranin O, and they were immunostained with antibodies against tryptase, collagen II, vimentin, and CD34. Immunological and inflammatory responses were studied by counting immune cells and evaluating blood vessels and collagen. Leukocyte-based inflammation prevailed during the implantation of decellularized unseeded scaffolds; meanwhile, plasma cells were significantly more abundant in tissue-engineered constructs. Mast cells were insignificantly more abundant in tissue-engineered construct samples. Conclusions: The seeding of decellularized xenogeneic cartilage with chondrocytes resulted in a change in immunological reactions upon implantation, and it was associated with plasma cell infiltration. Tissue-engineered grafts widely differed in design, including the type of used cells. The question of immunological response depending on the tissue-engineered graft composition requires further investigation.

Chronic biopsy proven post-COVID myoendocarditis with SARS-Cov-2 persistence and high level of antiheart antibodies.

PURPOSE: To study the clinical signs and mechanisms (viral and autoimmune) of myoendocarditis in the long-term period after COronaVIrus Disease 2019 (COVID-19). METHODS: Fourteen patients (nine male, 50.1 ± 10.2 y.o.) with biopsy proven post-COVID myocarditis were observed. The diagnosis of COVID-19 was confirmed by IgG seroconversion. The average time of admission after COVID-19 was 5.5 [2; 10] months. An endomyocardial biopsy (EMB) of the right ventricle was obtained. The biopsy analysis included polymerase chain reaction diagnosis of viral infection, morphological, immunohistochemical (IHC) examination with antibodies to CD3, CD45, CD68, CD20, SARS-Cov-2 spike, and nucleocapsid antigens. Coronary atherosclerosis was ruled out in all patients over 40 years. RESULTS: The new cardiac symptoms (congestive heart failure 3-4 New York Heart Association class with severe right ventricular involvement, various rhythm, and conduction disturbances) appeared 1-5 months following COVID-19. Magnetic resonance imaging showed disseminated or focal subepicardial and intramyocardial late gadolinium enhancement, hyperemia, edema, and increased myocardial native T1 relaxation time. Antiheart antibodies levels were increased 3-4 times in 92.9% of patients. The mean left ventricular (LV) ejection fraction (EF) was 28% (24.5; 37.8). Active lymphocytic myocarditis was diagnosed in 12 patients, eosinophilic myocarditis in two patients. SARS-Cov-2 RNA was detected in 12 cases (85.7%), in association with parvovirus B19 DNA-in one. Three patients had also endocarditis (infective and nonbacterial, with parietal thrombosis). As a result of steroid and chronic heart failure therapy, the EF increased to 47% (37.5; 52.5). CONCLUSIONS: COVID-19 can lead to long-term severe post-COVID myoendocarditis, that is characterized by prolonged persistence of coronavirus in cardiomyocytes, endothelium, and macrophages (up to 18 months) in combination with high immune activity. Corticosteroids and anticoagulants should be considered as a treatment option of post-COVID myoendocarditis.

Prospective two-arm study of the testicular function in patients with COVID-19.

BACKGROUND: The COVID-19 pandemic has led the international community to conduct extensive research into potential negative effects of the disease on multiple organs and systems in the human body. One of the most discussed areas is potential of the virus to compromise the testicular function. However, the lack of prospective studies on this topic makes it impossible to draw reliable conclusions on whether the disease affects the male reproductive system and, if so, to what extent. OBJECTIVES: The current trial is aimed at investigating the effect of SARS-CoV-2 on the testicular function, hormone levels and determining the extent of impact on spermatogenesis and damage to testicular tissue. MATERIALS AND METHODS: This prospective study included healthy controls and cases of patients suffering from viral pneumonia based on chest computed tomography (CT) and a positive SARS-CoV-2 throat swab exhibited moderate symptoms (World Health Organization (WHO) classification). Epidemiological, clinical, laboratory and ultrasound data were collected. A semen analysis was performed in cases during their hospital stay and 3 months after the discharge home. We also assessed the testicles obtained during autopsies of patients who died of COVID-19 (n = 20). RESULTS: A total of 88 participants were included (44 controls and 44 cases). Blood testosterone levels were significantly decreased in 27.3% of the cases (12/44). The mean level (7.3±2.7 nmol/L) was lower than that in the healthy controls (13.5±5.2 nmol/L, p < 0.001). An increase in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) was also detected compared to the healthy controls (p = 0.04 and p = 0.002). The semen analysis revealed decreased motility in COVID-19 patients (p = 0.001), and a higher number of immobile sperm (during COVID-19: 58.8% and at 3 months 47.4%, p = 0.005). All parameters returned to normal at 3 months after discharge. Direct mixed agglutination reaction (MAR) test at 3 months showed an increase of Ig A (p = 0.03). In the majority of autopsies (18/20), structural disorders of the testicular tissue, with signs of damage to germ cells were observed. DISCUSSION AND CONCLUSION: COVID-19 and its management strategies significantly affect male hormone levels and sperm quality at the onset of the disease. Postmortem examination of testicular tissue confirmed inflammation and viral infiltration of the testicles. However, in patients with moderate to severe disease, the studied parameters of the testicular function returned to normal values within 3 months.

Mesenchymal Stromal Cells Enhance Vascularization and Epithelialization within 7 Days after Gingival Augmentation with Collagen Matrices in Rabbits.

Soft gingival tissue deficiency remains a severe problem leading to postoperative recession, peri-implantitis, and bone resorption. The use of collagen matrices does not always lead to complete rebuilding of the gingiva volume. The application of mesenchymal stromal cells (MSCs) simultaneously with collagen materials represents a promising approach for the restoration of soft gingival tissues. However, short-term effects of MSCs-enriched collagen grafts after gingival augmentation have not yet been studied properly. Mucograft and Mucoderm matrices were implanted in rabbits (n = 12) simultaneously with the intraoperative injection of rabbit bone marrow-derived mesenchymal stromal cells (BM-MSCs) or without cells. Collagen matrices were implanted under the flap or by the surface technique without intentional primary closure. The samples were harvested seven days after implantation, histological staining with hematoxylin and eosin, and immunohistochemical staining for VEGF, IGF1, and TGF were performed. The use of Mucoderm led to better augmentation outcomes on day 7 compared with Mucograft (p < 0.0001). Gingival augmentation in combination with the local administration of BM-MSCs led to better regeneration of the soft gingival tissues independently of the type of implanted collagen matrices (p < 0.0001). Furthermore, injection of BM-MSCs significantly enhanced gingival vascularization and epithelization with a clear positive correlation between vascular growth and epithelial response. Administration of BM-MSCs in combination with various collagen materials may potentially improve gingiva regeneration.

Relapse-Free Survival and PD-L1 Expression in First High- and Low-Grade Relapsed Luminal, Basal and Double-Negative P53-Mutant Non-Muscular Invasive Bladder Cancer Depending on Previous Chemo- and Immunotherapy.

The goal of this study was to assess how PD-L1 expression in tissue specimens of patients with main molecular subtypes of NMIBC (luminal, basal and double-negative p53-mutant) associates with relapsed-free survival in dependence on the tumor grade and prior treatment of primary bladder cancer. PD-L1 expressions on the membrane of neoplastic and CD8+ immune cells were assessed in tumor specimens (n = 240) of primary and relapsed luminal, basal and double-negative p53-mutant NMIBC. Association between relapse-free survival and PD-L1 expression was estimated for high- and low-grade relapsed NMIBC according to previous treatment and their molecular profile, using the Kaplan-Meier method, and assessed by using the log-rank test. Potential confounders were adjusted by Cox regression models. In a group of patients who underwent only TUR without intravesical therapy, there were significant differences in relapse time between high- and low-grade tumors in basal and luminal molecular subtypes; for basal relapsed carcinoma, RFS was shorter in cases where tumors were less malignant. Both intravesical mitomycin and Bacillus Calmette-Guerin (BCG) therapy significantly extended the time of recurrence of low-grade luminal and basal bladder malignancies with no intergroup differences in double-negative NMIBC. PD-L1 expression status was associated with RFS for luminal relapsed NMIBCs in the group without previous frontline intervention, and with RFS in the group of patients with luminal relapsed bladder cancer previously utilized BCG. Obtained results may be considered as a promising approach for further clinical implementation.