Assessment of Longitudinal Changes in Endothelial Function and Oxidative Stress in Normotensive Patients With ADPKD

The purpose of this study is to determine whether patients with autosomal dominant polycystic kidney disease (ADPKD) present with abnormal endothelial function, increased levels of NOX4 activity and mitochondrial abnormalities, contributing to oxidative stress from early stages that correlate with disease severity.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic and the fourth cause of end-stage renal disease (ESRD) in adults worldwide. Cardiovascular diseases are the most important non-cystic complications and continue to be the leading cause of premature mortality in these patients. Hypertension (HTN) is present in approximately 50% of the patients at early stages, and increases to nearly 100% at ESRD. Furthermore, HTN contributes to the underlying renal disease progression. Nitric oxide (NO) associated endothelium-dependent vasorelaxation has been shown to be impaired in small subcutaneous resistance vessels from patients with ADPKD before the development of HTN. However, the principal contributors to vascular dysfunction remain unclear.

The investigators broad objective is to evaluate the presence and extent of endothelial dysfunction and its association with oxidative stress in young normotensive patients with ADPKD, with the long term goal of timely intervention to slow the progression of the disease in these patients.

Participants in this study will have their endothelial function assessed using a non-invasive technique, peripheral arterial tonometry (PAT), which has been shown to be a useful, highly reproducible, and non-operator dependent method for non-invasive assessment of vascular health. The investigators will assess longitudinal changes in endothelial function using PAT with the intention of establishing if this methodology offers the potential of non-invasive measures of early vascular disease in young normotensive patients with ADPKD. Biochemical markers of endothelial dysfunction will be assessed concomitantly. In addition, the investigators will assess oxidative stress levels in these patients, with the intention of determining the association with endothelial dysfunction.

Eligibility Criteria:
Inclusion Criteria:

ADPKD Patients:

* ADPKD (based on Ravine et al. criteria)
* Class 1 B-D according to our imaging classification
* Male and female subjects 18 - 40 years of age, inclusive
* Estimated GFR\> 60 mL/min/m2 (CKD-Epi equation)
* Systolic BP≤130mmHg without taking HTN medications
* Ability to provide written, informed consent

Healthy controls:

* Male and female subjects 18 - 40 years of age, inclusive
* estimated GFR\> 60 mL/min/m2 (CKD-EPI equation)
* Systolic BP≤130mmHg without taking HTN medications
* Ability to provide written, informed consent

Exclusion Criteria:

ADPKD Patients:

* Class 2 according to our imaging classification
* Concomitant systemic disease in the kidney (e.g. lupus, hepatitis B or C, amyloidosis)
* Diabetes mellitus (fasting glucose \> 126 mg/dL or treatment with insulin or oral hypoglycemics).
* Predicted urine protein excretion in urinalysis \>1 g/24 hrs
* Abnormal urinalysis suggestive of concomitant glomerular disease
* Subjects having contraindications to, or interference with MRI assessments. \[For example: ferromagnetic metal prostheses, aneurysm clips, severe claustrophobia, large abdominal/back tattoos, etc\].
* Female subjects that are pregnant

Healthy controls:

* Previous personal or family history of kidney disease
* Concomitant systemic disease in the kidney (e.g. lupus, hepatitis B or C, amyloidosis)
* Diabetes mellitus (fasting glucose \> 126 mg/dL or treatment with insulin or oral hypoglycemics).
* Presence of proteinuria
* Abnormal urinalysis suggestive glomerular disease
* Subjects having contraindications to, or interference with MRI assessments. \[For example: ferromagnetic metal prostheses, aneurysm clips, severe claustrophobia, large abdominal/back tattoos, etc\]
* Female subjects that are pregnant