[Costal cartilage changes in children with pectus excavatum and pectus carinatum]. / Izmeneniia rebernogo khriashcha pri voronkovidnoi i kilevidnoi deformatsii grudnoi kletki u detei.

Pectus excavatum (PE) and pectus carinatum (PC) in children are the most common congenital deformities that cause complications in the thoracic organs; however, the role of chondrocytes and cartilage canals in the pathogenesis of these conditions remains unexplored. OBJECTIVE: To investigate qualitative and quantitative changes of cartilage lacunae and canals in the costal cartilages in children with PE and PC compared to those with normal chests. SUBJECT AND METHODS: Costal cartilages were investigated in 10 children with normal chests (a control group), in 12 children with PE, and in 12 children with PC. Tissue fragments were fixed in 10% neutral formalin and embedded in compacted paraffin. Sections were stained with hematoxylin and eosin. Slides were examined by light microscopy. Cartilage lacunae, hyper- and hypolacunar zones, and cartilage canals were morphometrically examined, followed by statistical data analysis. RESULTS: There was a significant decrease in the number of cartilage lacunae and in the frequency of hyperlacunar zones and an increase in that of hypolacunar zones in the PE and PC groups. There were no significant differences in these parameters between the PE and PC groups; however, there was a tendency to the smallest number of cartilage lacunae and canals in the PC group and that to the preponderance of empty lacunae in the PE group. Only the PC group showed also negative correlations between the proportions of empty lacunae and the age of children. CONCLUSION: The pathogenesis of PE and PC in children is related to the impaired trophism of costal cartilages due to the smaller number of cartilage channels containing vessels and lacunae with chondrocytes. The development of PE and PC is associated with specific costal cartilage morphological changes that suggest that PE and PC are different manifestations of the same disease, namely connective tissue dysplasia.

[Costal cartilage structural and functional changes in children with a funnel or keeled chest]. / Strukturnye i funktsional'nye izmeneniia rebernykh khriashchei pri voronkovidnoi i kilevidnoi deformatsii grudnoi kletki u detei.

Congenital chest wall deformities (CCWDs) in children are severe diseases leading to cosmetic defects and diseases of the respiratory and cardiovascular systems. The most common of these deformities are funnel-shaped (pectus excavatum, FD) and keeled (pectus carinatum, KD) ones. The pathogenesis of CCWDs and the role of costal cartilage structural and functional changes in their pathogenesis have now been not well studied, which makes it difficult to elaborate pathogenetic approaches to correcting these diseases. Analysis of the literature has shown that structural and functional changes occur in the matrix and chondrocytes from the costal cartilage in FD. Similar costal cartilage changes are observed in KD. It is still unknown exactly which pathological processes are present in the costal cartilage and how they result in the development of one or other type of CCWDs. The role of amianthoid transformation (AT) of costal cartilages in these processes is also unknown. It is not improbable that it is AT drastically changing the native cartilage matrix, which is one of the key mechanisms leading to changes in its properties and to the subsequent development of FD or KD.

[The morphological and morphometric study of amianthoid transformation of the costal cartilage in health and in keeled chest deformity in children]. / Morfologicheskoe i morfometricheskoe issledovanie amiantoidnoi transformatsii rebernykh khryashchei v norme i pri kilevidnoi deformatsii grudnoi kletki u detei.

Amianthoid transformation (AT) is the accumulations of abnormal collagen structures (amianthoid fibers) in the hyaline cartilages, tumors, and tendons. Neither functional value of costal cartilage matrix AT, nor its role in the pathogenesis of congenital chest deformities is known now. AIM: to examine the morphological features of AT in the costal cartilage of children with the normal and keeled chest. SUBJECTS AND METHODS: Costal cartilages were studied in 6 children with the normal chest (autopsy material) and in 5 ones with keeled chest (surgical material). Tissue fragments were fixed in 10% neutral formalin and embedded in compacted paraffin. The sections were stained with hematoxylin and eosin, picrofuchsin by van Gieson, with picrosirius, toluidine blue and by the Malaurie method modified by Gallego. The specimens were examined by light, phase-contrast, dark-field, fluorescence, and polarization microscopy. The frequency of AT sites and their area were morphometrically studied and the findings were then statistically processed. RESULTS: Various types of AT in the costal cartilages were described as both the normal and keeled chest. According to their morphological features, classic, fine-fiber, twisted, and intralacunar types were identified. There were statistically significant increases in the incidence of all types (except the intralacunar one) and in the area of the fine-fiber AT type in keeled chest deformity as compared to health. There were positive correlations between the area of classic, intralacunar, and twisted types in both groups and between the area of a classic type and age in the controls. CONCLUSION: A classification of AT areas varying in structures in health and disease has been given for the first time; their relation to each other and to the presence of keeled deformity shown, which, in our opinion, suggests that AT is implicated in the pathogenesis of the disease.

[PLGA mesh-collagen hybrid scaffold and tissue-engineered product in substitution urethroplasty: experimental validation].

Urethral strictures are a pressing issue in modern medicine. Substitution urethroplasty is considered one of the most effective treatment methods. However, despite the surgery showing good results, many problems remain unresolved, one being substitute material deficiency in extensive or recurrent strictures, as well as in cases requiring multistage surgeries, including those used to treat hypospadias. Graft removal also leaves the donor area prone to diseases and increases the length of surgery leading to a higher risk of intra- and postoperative complications. Tissue engineering (namely tissue-engineered products comprised of scaffolds and cells) may be a useful tool in dealing with these issues. The authors assessed the characteristics of a novel hybrid scaffold created from "reconstructed" collagen and a poly(lactic-co-glycolic acid) mesh. The resulting composite product showed good mechanical properties and functional performance. The hybrid scaffold was non-cytotoxic and provided an adequate base for cell adhesion and proliferation. Biodegradation resulted in the scaffold being replaced by urothelium and urethral mucosa. The newly formed tissues possessed adequate structural and functional properties. Only one rabbit out of 12 developed urethral stricture at the site of scaffold implantation. The above-mentioned facts suggest that the novel hybrid scaffold is a promising tissue-engineered product with potential implication in substitution urethroplasty.

[Morphology of collagen matrices for tissue engineering (biocompatibility, biodegradation, tissue response)].

OBJECTIVE: to perform a comparative morphological study of biocompatibility, biodegradation, and tissue response to implantation of collagen matrices (scaffolds) for tissue engineering in urology and other areas of medicine. MATERIAL AND METHODS: Nine matrix types, such as porous materials reconstructed from collagen solution; a collagen sponge-vicryl mesh composite; decellularized and freeze-dried bovine, equine, and fish dermis; small intestinal submucosa, decellularized bovine dura mater; and decellularized human femoral artery, were implanted subcutaneously in 225 rats. The tissues at the implantation site were investigated for a period of 5 to 90 days. Classical histology and nonlinear optical microscopy (NLOM) were applied. RESULTS: The investigations showed no rejection of all the collagen materials. The period of matrix bioresorption varied from 10 days for collagen sponges to 2 months for decellularized and freeze-dried vessels and vicryl meshes. Collagen was prone to macrophage resorption and enzymatic lysis, being replaced by granulation tissue and then fibrous tissue, followed by its involution. NLOM allowed the investigators to study the number, density, interposition, and spatial organization of collagen structures in the matrices and adjacent tissues, and their change over time during implantation. CONCLUSION: The performed investigation could recommend three matrices: hybrid collagen/vicryl composite; decellularized bovine dermis; and decellularized porcine small intestinal submucosa, which are most adequate for tissue engineering in urology. These and other collagen matrices may be used in different areas of regenerative medicine.