Sustained Decrease in Blood Pressure and Reduced Anatomical and Functional Reinnervation of Renal Nerves in Hypertensive Sheep 30 Months After Catheter-Based Renal Denervation

We examined whether renal denervation (RDN) reduced blood pressure (BP), improved glomerular filtration rate, albuminuria, and left ventricular mass in sheep with hypertensive chronic kidney disease (CKD). To examine whether renal nerve function returned in the long term, we examined vascular contraction to nerve stimulation in renal arteries and determined nerve regrowth by assessing renal TH (tyrosine hydroxylase), CGRP (calcitonin gene-related peptide), and norepinephrine levels in kidneys at 30 months after RDN. RDN normalized BP in hypertensive CKD sheep such that BP was similar to that of the normotensive sheep with intact nerves. Glomerular filtration rate decreased by approximate to 22% in CKD sheep with intact nerves but increased approximate to 26% in hypertensive CKD-RDN sheep by 30 months. At 30 months, urinary albumin was approximate to 127% and left ventricular mass was approximate to 41% greater in CKD sheep with intact nerves than control. However, urinary albumin was approximate to 60% less and left ventricular mass was approximate to 40% less in the CKD sheep that underwent RDN compared with intact counterpart. At 30 months in CKD-RDN sheep, neurovascular contraction (approximate to 56%), renal proportion of TH (approximate to 50%), CGRP (approximate to 67%), and norepinephrine content (approximate to 49%) were all less than CKD-intact; all these variables were similar between normotensive-intact and normotensive-RDN groups. RDN caused a sustained reduction in BP and improvements in renal function. Regrowth of renal nerves and return of function were observed in hypertensive CKDRDN sheep, but levels were only partially restored to levels of intact. These suggest that RDN lowers BP in the long term and is renoprotective and cardioprotective as a result of lesser nerve regrowth in CKD.