Amianthoid transformation of costal cartilage matrix in children with pectus excavatum and pectus carinatum.

BACKGROUND: It is unclear if amianthoid transformation (AT) of costal cartilage extracellular matrix (ECM) has an impact on the development of pectus excavatum (PE) and pectus carinatum (PC). METHODS: AT foci were examined in intrasurgical biopsy specimens of costal cartilages of children (8-17 years old) with PE (n = 12) and PC (n = 12) and in age-matching autopsy control samples (n = 10) using histological and immunohistochemical staining, atomic force and nonlinear optical microscopy, transmission and scanning electron microscopy, morphometry and statistics. RESULTS: AT areas were identified in the costal cartilage ECM in children with normal chest, PE and PC. Each type of the AT areas ("canonical", "intertwined", "fine-fibred" and "intralacunary") had a unique morphological pattern of thickness and alignment of amianthoid fibers (AFs). AFs were formed via lateral aggregation of collagen type II fibrils in the intact ECM. Foci of the AT were observed significantly more frequently in the PE and PC groups. The AT areas had unique quantitative features in each study group. CONCLUSION: AT is a structurally diverse form of ECM alteration present in healthy and pathological costal cartilage. PE and PC are associated with specific AT disorders.

Repair of pectus carinatum, carinatum/excavatum complex patients with doubly double bar technique.

Surgical correction is needed for patients with pectus carinatum who do not adapt to bracing therapy. We performed the doubly double bar technique for ten patients who did not adapt to bracing therapy for patients with pectus carinatum and/or carinatum/excavatum complex type. A complete correction was achieved for all patients, and there were no complications. Our initial experience suggests that the doubly double bar technique can be performed effectively for pectus carinatum and/or carinatum/excavatum complex type patients.

Abnormal response of costal chondrocytes to acidosis in patients with chest wall deformity.

Costal cartilage is much understudied compared to the load bearing cartilages. Abnormally grown costal cartilages are associated with the inherited chest wall deformities pectus excavatum and pectus carinatum resulting in sunken or pigeon chest respectively. A lack of understanding of the ultrastructural and molecular biology properties of costal cartilage is a major confounder in predicting causes and outcomes of these disorders. Due to the avascular nature of cartilage, chondrocytes metabolize glycolytically, producing an acidic environment. During physical activity hydrogen ions move within cartilage driven by compressive forces, thus at any one time, chondrocytes experience transient changes in pH. A variety of ion channels on chondrocytes plasma membrane equip them to function in the rapidly changing conditions they experience. In this paper we describe reduced expression of the ASIC2 gene encoding the acid sensing ion channel isoform 2 (previously referred to as ACCN1 or ACCN) in patients with chest wall deformities. We hypothesized that chondrocytes from these patients cannot respond normally to changes in pH that are an integral part of the biology of this tissue. Activation of ASICs indirectly creates a cascade ultimately dependent on intracellular calcium transients. The objective of this paper was to compare internal calcium signaling in response to external pH changes in costal chondrocytes from patients with chest wall deformities and healthy individuals. Although the molecular mechanism through which chondrocytes are regulated by acidosis remains unknown, we observed reduced amplitudes of calcium rise in patient chondrocytes exposed to low pH that become further impaired upon repeat exposure.

[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.