Long-term effects of the endothelin(A) receptor antagonist LU 135252 and the angiotensin-converting enzyme inhibitor trandolapril on diabetic angiopathy and nephropathy in a chronic type I diabetes mellitus rat model.
Diabetic angiopathy is a serious problem in antidiabetic therapy. We wanted to investigate whether treatment with the endothelin(A) receptor antagonist LU 135252 or with the angiotensin-converting enzyme inhibitor trandolapril might prevent angiopathy in long-term type I diabetes mellitus. Six groups of male Wistar rats were investigated: untreated age-matched control rats, healthy controls treated with trandolapril (0.3 mg/kg), healthy controls treated with LU 135252 (100 mg/kg), untreated diabetic rats, and diabetic rats treated with either trandolapril or LU 135252. Rats were rendered diabetic by injection of streptozotozin. Duration of the disease was 6 months. Thereafter, rats were sacrificed, and hearts, kidneys, and a mesenterial loop were removed. Hearts and kidneys were processed histologically; the mesenterial loop was perfused with saline at constant pressure for investigation of microvessels using microvideoangiometry while treated with either 30 mM KCl, 1 microM acetylcholine, or 1 microM sodium nitroprusside. All diabetic rats developed hyperglycemia without differences among these three groups. Diabetic rats exhibited marked anemia, which was significantly antagonized by both treatments. The heart capillaries/muscle fibers ratio was decreased significantly in diabetic animals, which was prevented fully by both treatments. Renal glomerular diameter was increased in diabetic rats. This was significantly antagonized by LU 135252 but not by trandolapril. Deposition of homogeneous eosinophilic material within the glomeruli was nearly completely prevented by LU 135252. The acetylcholine-induced vasodilation in mesenteric microvessels was significantly attenuated in diabetic rats, which was significantly antagonized by both treatments. We conclude that both angiotensin and endothelin seem to contribute to the development of diabetic angiopathy and that, in addition to angiotensin-converting enzyme inhibition, blockade of endothelin(A) receptors may be an interesting new approach to antiangiopathic therapy.
Dhein
S
S
Institute of Pharmacology, University of Halle, Halle, Germany. stefan.dhein@medizin.uni-halle.de
Hochreuther
S
S
Aus Dem Spring
C
C
Bollig
K
K
Hufnagel
C
C
Raschack
M
M
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001808:Blood Vessels / Q000473:pathology; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D065128:Endothelin Receptor Antagonists; D004730:Endothelium, Vascular / Q000473:pathology; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D006339:Heart Rate / Q000187:drug effects; D007211:Indoles / Q000627:therapeutic use*; D007677:Kidney Function Tests; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D010666:Phenylpropionates / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D044022:Receptor, Endothelin A
D000806:Angiotensin-Converting Enzyme Inhibitors; D001786:Blood Glucose; D065128:Endothelin Receptor Antagonists; D007211:Indoles; D010666:Phenylpropionates; D011743:Pyrimidines; D044022:Receptor, Endothelin A; C052035:trandolapril; C107831:darusentan