Article TGF Expression and Macrophage Accumulation in Atherosclerotic Renal Artery Stenosis

Background and objectives Atherosclerotic renal artery stenosis (ARAS) reduces renal blood flow and is a potential cause of chronic kidney injury, yet little is known regarding inflammatory pathways in this disorder in human participants. This study aimed to examine the hypothesis that reduced renal blood flow (RBF) in ARAS would be associated with tissue TGF-b activation and inflammatory cell accumulation. Design, setting, participants, & measurements This cross-sectional study of ARAS of varying severity compared transjugular biopsy specimens in patients with ARAS (n=12, recruited between 2008 and 2012) with tissue from healthy kidney donors (n=15) and nephrectomy specimens from individualswith total vascular occlusion (n=65). ARAS patients were studied under controlled conditions to measure RBF by multidetector computed tomog-raphy and tissue oxygenation by blood oxygen level–dependent magnetic resonance imaging. ResultsComparedwith the nonstenotic contralateral kidneys, RBFwas reduced in poststenotic kidneys (2426149 versus 365+174 ml/min; P,0.01) as was single-kidney GFR (28617 versus 41619 ml/min; P,0.01), whereas cortical and medullary oxygenation were relatively preserved. Tissue TGF-b immunoreactivity was higher in ARAS patients compared with those with both normal kidneys and those with total occlusion (mean score 2.460.7 versus 1.5+1.1 in the nephrectomy group and versus 060 in donors; P,0.01). By contrast, the number of CD68+ macrophages was higher with greater disease severity (from 2.262.7 in normal to 22.4618 cells/high-power field in nephrectomy samples; P,0.001). Conclusions The results of this study indicate robust stimulation of TGF-b associated with macrophage infil-tration within the human kidney with vascular occlusive disease