Estimated glomerular filtration rate (eGFR), 25(OH) D3, chronic kidney disease (CKD), the MYH9 (myosin heavy chain 9) gene in old and very elderly people.

Abstract

It is known that the common physiological denominator of the ageing process is an attenuation of functional performance with respect to the situation of young people and adults. However, since the first cohort-based longitudinal studies, it has not been possible to establish a "linear" relationship between age and glomerular filtration in all cases. This does not mean that there is no physiological ageing process at all; in addition to those already elucidated, its mechanisms include cell senescence, podocyte dysfunction, a vitamin D deficiency, and homozygotic forms of the MYH9 gene. The aim of the present work was to analyse the prevalence of chronic kidney disease (CKD) and, where possible, the correlation between CKD, defined by an eGFR < 60 ml/min/1.73 m(2), plasma 25(OH)D3 levels and the MYH9 gene in a population of elderly and very elderly persons. These parameters have not been evaluated previously in populations of elderly and very elderly patients. It is concluded that a moderate decrease in the eGFR occurs with age. This does not imply the presence of CKD in elderly people, since in most individuals the reduced eGFR is not accompanied by anaemia, and no individuals show hypocalcaemia, hyperphosphataemia or a high Alb/Cr ratio. Here we observed a lower Hb level and an elevated Alb/Cr ratio in subjects heterozygotic for the MYH9 gene. This could be interpreted in the sense that the gene could exert some protective effect on renal function, whereas the heterozygotic form (allele A) of the MYH9 gene could be considered a very early marker, a new risk factor for the appearance of CKD, or a sign of renal frailty in elderly people.