ACE-inhibition is Superior to Endothelin A Receptor Blockade in Preventing Abnormal Capillary Supply and Fibrosis of the Heart in Experimental Diabetes
Overview
Affiliations
Aims/hypothesis: There is little information whether cardiac capillary supply is deranged in diabetes. Hyperglycaemia is a potent stimulus for endothelin-1 (ET-1) production. We therefore hypothesised that increased ET-1 production in Streptozotocin-induced Type 1 diabetes causes abnormalities of cardiac capillaries and the aorta. To this end we compared the effects of an ET receptor A blocker (ETA-RB) with that of an ACE-inhibitor (ACE-i) or their combination in rats with Streptozotocin (STZ) diabetes.
Methods: Sprague Dawley rats were injected with 65 mg STZ i.v. and subsequently developed diabetes. Rats were left untreated or received daily either the ACE-i Trandolapril, the ETA-RB Darusentan or a combination of both. After 6 months the experiment was terminated and the heart and the aorta were investigated using quantitative morphological techniques.
Results: ACE-i but not ETA-RB lowered blood pressure in STZ Type 1 diabetic rats. Capillary length density was lower in untreated STZ diabetic rats (2932+/-128 mm/mm3) compared to non-diabetic control rats (3410+/-252 mm/mm3). Treatment with ACE-i (3568+/-431 mm/mm3), but not with ETA-RB (2893+/-192 mm/mm3), prevented the decrease in capillary supply. Volume density of the myocardial interstitium was higher in untreated STZ diabetic rats (0.86+/-0.04%) compared to non-diabetic control rats (0.36+/-0.06%). In all three intervention groups the values were lower (ACE-i: 0.53+/-0.05%, ETA-RB: 0.7+/-0.08% and combination: 0.69+/-0.1).
Conclusion/interpretation: Our study identifies a capillary defect of the heart in STZ diabetes, i.e. decreased capillary supply. This abnormality was reversed by ACE-i, but not by ETA-R blockade. A similar trend, although not complete normalisation, was seen in cardiac fibrosis.
The Potential of Albuminuria as a Biomarker of Diabetic Complications.
Raja P, Maxwell A, Brazil D Cardiovasc Drugs Ther. 2020; 35(3):455-466.
PMID: 32681438 PMC: 8105227. DOI: 10.1007/s10557-020-07035-4.
Pan M, Han Y, Basu A, Dai A, Si R, Willson C Am J Physiol Cell Physiol. 2018; 314(6):C732-C740.
PMID: 29513568 PMC: 6334999. DOI: 10.1152/ajpcell.00350.2017.
Obesity-induced vascular inflammation involves elevated arginase activity.
Yao L, Bhatta A, Xu Z, Chen J, Toque H, Chen Y Am J Physiol Regul Integr Comp Physiol. 2017; 313(5):R560-R571.
PMID: 28835451 PMC: 5792147. DOI: 10.1152/ajpregu.00529.2016.
Endothelin and the glomerulus in chronic kidney disease.
Barton M, Sorokin A Semin Nephrol. 2015; 35(2):156-67.
PMID: 25966347 PMC: 4731878. DOI: 10.1016/j.semnephrol.2015.02.005.
VDAC: old protein with new roles in diabetes.
Sasaki K, Donthamsetty R, Heldak M, Cho Y, Scott B, Makino A Am J Physiol Cell Physiol. 2012; 303(10):C1055-60.
PMID: 22972802 PMC: 3492836. DOI: 10.1152/ajpcell.00087.2012.