Compositional changes of the xiphoid process and costal cartilage with aging

To elucidate compositional changes of the cartilage with aging, the authors investigated age-related changes of element contents in the xiphoid process and costal cartilage by inductively coupled plasma-atomic emission spectrometry. After the ordinary dissection by medical students was finished, the xiphoid processes and bilateral the fourth costal cartilages were resected and element contents were determined. The subjects consisted of 17 men and 9 women, ranging in age from 52 to 96 yr. No significant correlations were found between age and the content of elements, such as Ca, P, S, Mg, Na, Zn, Fe, and Si in the xiphoid process and costal cartilage, except for S in the costal cartilage, in which an extremely significant correlation was found. With regard to the relationships among element contents, the common finding that there were significant direct correlations both between Ca and P contents and between Ca and Mg contents, whereas there were significant inverse correlations both between Ca and S contents and between P and S contents obtained in the xiphoid process and costal cartilage.