Arterial Stiffness in Children and Young People With Hypertension and Chronic Kidney Disease

Age related stiffening and hardening of the arteries is often a slow process, but some conditions such as chronic kidney disease (CKD), seem to increase the rate at which the arteries stiffen even during childhood. High blood pressure (BP) is well known to lead to arterial stiffening and is often seen in children and young people (CYP) with CKD. A greater risk of arterial stiffening has been reported in children CYP with CKD compared to healthy CYP and this is thought to be related to the development of high BP, heart problems, and the worsening of kidney damage. The cause is unknown and is unlikely due to age related changes in the arterial wall seen in older adults. Potential mechanisms contributing to arterial stiffening in CYP with CKD include i) abnormalities in the interaction between the heart and the aorta (the large artery pumping blood away from the heart to the rest of the body), overactivity of the sympathetic nervous system (SNS), the body's "stress response", or iii) abnormal metabolism seen in CKD, where there are high levels of phosphate and other waste products circulating in the blood as a result of damage to the kidneys. In this study, the investigators will use a variety of non invasive experimental methods to determine if arterial stiffening seen in CYP with CKD is due solely to increased BP, or whether the other potential factors listed above also contribute. This may help to eventually identify how to prevent or treat arterial stiffness in CYP with CKD and prevent its adverse impact on kidney and heart health in later life. The investigators will compare findings between those with CKD and an age, sex and BP matched control group. This control group will comprise CYP both with high BP (primary hypertension) and without high BP (healthy participants).