Serum Uremic Toxins and Histological Findings of the Blood Vessels in Dialysis Patients

Patients treated by chronic renal replacement therapy are exposed to cardiovascular problems and suffer from an accelerated and sever atherosclerosis. Classical risk factors for atherosclerosis and cardiovascular diseases (CVD) do not explain the full risk of CVD in the dialysis patients. Additional risk factors are therefore likely to exist. The uremic syndrome is attributed to the progressive retention of a large number of compounds, which under normal conditions are excreted by the healthy kidneys. Uremic toxins such are parathormone (PTH), vitamin D and phosphates, cause development of renal osteodystrophy (ROD), i.e. disordered calcium and phosphate metabolism. Both conditions of hyperparathyroid and adynamic bone disease (ABD) lead to an elevated calcium x phosphate product and increased vascular calcification, which might occur in intimal and medial layer of the vessel wall. It is important to consider these processes separately, as the vascular consequences (occlusion with atheromatosis and vascular stiffening through medial calcification) are different. Moreover, the difference between uremic and non-uremic intimal plaque is not the size but its composition, with markedly increased calcium content. Hence, these observations have an important socio-economic impact because of the increased cardiovascular morbidity and mortality. The investigators hypothesized that uremic toxins in dialysis patients influence directly and/or indirectly the development of atherosclerosis, vascular calcifications and CVD.