Valve degeneration is one of the most common lesions to affect the heart. Floppy mitral valve is a frequent pathology in adults but degeneration of the collagen fibres of the leaflet is also seen in children. This congenital condition is described as dysplastic mitral leaflets. Few cases have an identified genetic defect, for the majority of adults and children the cause of the disruption is unknown. In this descriptive investigation, histological and 'immunohistological methods were used on human mitral valves. Forty children, (17 dysplastic [mean 2.9 years]), 23 control leaflets [mean 4.3 years]) were studied along with 41 adult leaflets (20 floppy [mean 31.8 years] and 21 controls [mean 36.2 years]). Semi-quantitative analysis of the location of type I collagen, type I procollagen, MMP-1, TIMP-1, TGF-~ and decorin were described within the layers. Scanning electron microscopy (SEM) immunogold analysis was used to investigate the location of decorin, which is involved in collagen fibrillogenesis, in the abnormal leaflets. Morphologically, the normal mitral valve has an atrial overlay of immature tissue from 1-week old. Under 1 year old the dysplastic leaflets had commissural fusion of the leaflets and some fused directly onto the papillary muscle, a feature not seen in adult floppy leaflets.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:577459 |
| Date | January 2012 |
| Creators | McCarthy, Karen Patricia Mary |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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