[The cellular composition of explanted bioprosthetic heart valves in infective endocarditis]. / Kletochnyi sostav éksplantirovannykh bioprotezov klapanov serdtsa pri infektsionnom éndokardite.

OBJECTIVE: To perform immunohistochemical typing of cells as a component of bioprosthetic (BP) heart valves explanted during reoperations for prosthetic valve endocarditis. MATERIAL AND METHODS: The authors investigated 8 models of KemCor and PeriCor artificial heart valves produced by NeoCor Company (Kemerovo, Russia), which were explanted from the mitral position due to infection of xenogeneic implanted material. The following markers: CD3 (T-lymphocytes), CD20 (B-lymphocytes), CD34 and VEGFR2 (endotheliocytes), CD68 (monocytes/macrophages), vimentin (fibroblasts), and α-smooth muscle actin (smooth muscle cells), were used for immunohistochemical typing of cells as a component of the analyzed samples. RESULTS: Recipient cells were found to colonize devitalized BP tissues in infective endocarditis. This process simultaneously involved several types of cells performing their functions in infectious lesion and its initiation of BP remodeling. Macrophages contributed to the sanitation of the foci of infection and destruction of BP xenotissue; endotheliocytes ensured neovascularization and resistance of the implanted valve surface to infection; fibroblasts played a role in the neoplastic transformation of collagen, and smooth muscle cells were likely to take on the role in forming the elastic framework of a leaflet and in ensuring the mechanical properties of the bioprosthesis. CONCLUSION: In the time course of development of prosthetic endocarditis, the recipient cells populate xenovalve leaflets that are a modified extracellular matrix obtained from the porcine aortic valve complex. This process is a consequence of the destruction of the BP surface and deep components. The observed cellular reactions are likely to be adaptive and to be aimed at eliminating microorganisms and regenerating structural damages.

[Histological study of urethral plate: a search of the best material for surgical treatment of hypospadias in children].

AIM: to study the microstructure of the urethral plate in patients with a proximal form of hypospadias to justify the use of tissues from the ventral penile surface when creating an artificial urethra. MATERIALS AND METHODS: A histological study of surgical specimens from 10 patients with proximal hypospadias was carried out. The urethral plate, a strip of tissue from the ectopic external urethral orifice located in the penoscrotal angle, to the coronary sulcus, was completely excised and processed by various techniques. A staining with hematoxylin and eosin, picrofuchsin according to Van Gieson, as well as immunohistochemical typing of CD 34, collagen (type I, III, and IV), fibronectin, and smooth myocytes using alpha-smooth muscle actin was performed. RESULTS: All elements which are present in a healthy urethra, such as epithelial cells, blood vessels, normal collagen fibers, smooth muscle cells and complexes of glands, were found in the microstructure of the urethral plate. CONCLUSION: The cytoarchitectonic features of the ventral penile tissues are similar to the microstructure of the healthy urethra, which provides a rationale to consider the urethral plate as a material with optimal bioresistant properties for urethroplasty.

[Cellular Composition of Calcified Bioprosthetic Heart Valves].

With the aim to assess the mechanisms of the structural dysfunctions associated with xenograft tissue calcification, we investigated the cellular composition of the explanted xenoaortic epoxy-treated bioprosthetic heart valves. In the leaflets, we revealed multiple cells with retained internal structure. Most of them located on the leaflet surface, at the areas of collagen destruction, and near calcium deposits. Monocytes were the predominant cell fraction on the leaflet surface whilst immune (macrophages, multinucleated giant cells, plasma cells, neutrophils) and connective tissue (fibroblasts, fibrocytes, endothelial, and smooth muscle cells) cells prevailed at the areas of collagen destruction and near calcium deposits. Calcification of the leaflets was accompanied by cellular infiltration, therefore suggesting that pathological mineralization may be associated with cell-mediated processes.