[Permissive effect of PTH on vascular wall hypertrophy of intramyocardial arteries in experimental renal failure]. / Permissiver Effekt von PTH auf die Gefässwandverdickung intramyokardialer Arterien bei experimenteller Niereninsuffizienz.

BACKGROUND: Abnormalities in cardiovascular structure e.g. LV hypertrophy and thickening of vessels (elastic and peripheral arteries, veins) are hallmarks of renal failure. Among other hormones parathyroid hormone (PTH) has been shown to affect cardiac function and has also been identified at a permissive factor for the activation of the cardiac interstitium leading to myocardial fibrosis. The present study was designed to examine whether PTH was also permissive for intramyocardial arteriolar wall thickening in an experimental model of renal failure. MATERIAL AND METHODS: Sham operated or subtotally nephrectomized rats (SNX) were parathyroidectomized (PTX) and received either saline or rat 1,34 PTH by osmotic minipump. After perfusion fixation, intramyocardial arterioles were assessed using stereological techniques (wall thickness, wall/lumen ratio, minimal lumen diameter, length density). RESULTS: Wall thickness of intramyocardial arterioles was significantly higher in SNX than in sham-op controls. SNX-PTX animals receiving solvent did not differ from sham-op controls while SNX-PTX animals receiving PTH had increased values which were comparable with those of SNX. In addition, PTH treated animals showed signs of marked vascular smooth-muscle cell and endothelial cell activation. CONCLUSIONS: The data suggest that intramyocardial arteriolar wall thickening in experimental renal failure and probable changes of vessel architecture in renal insufficiency in general are dependent upon the permissive effect of PTH.