Vascular endothelin converting enzyme-1 expression and activity is upregulated in clinical diabetes

Circulating and vascular endothelin-1 (ET-1) levels are elevated in diabetes, but the molecular components of the enzymatic activation of ET-1 in the vasculature remains unknown. Furthermore, the distribution of ET receptors favors a contractile phenotype in African Americans with diabetes. Whether...

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Bibliographic Details
Published in:Ethnicity & disease 2002-09, Vol.12 (4), p.S3-5ff
Main Authors: Anstadt, Mark P, Hutchinson, Jimmie, Portik-Dobos, Vera, Jafri, Farahdiba, Bannan, Mary, Mawulawde, Kwabena, Ergul, Adviye
Format: Article
Language:English
Subjects:
African Americans
Aspartic Acid Endopeptidases - genetics
Aspartic Acid Endopeptidases - metabolism
Cardiovascular Disease
Case-Control Studies
Caucasians
Comparative analysis
Diabetes
Diabetes Mellitus, Type 2 - enzymology
Diabetes Mellitus, Type 2 - ethnology
Endothelin-Converting Enzymes
Endothelium, Vascular - enzymology
Female
Health and Medicine
Humans
Male
Medical research
Metalloendopeptidases
Reverse Transcriptase Polymerase Chain Reaction
RNA, Messenger - genetics
United States
Up-Regulation
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Summary:Circulating and vascular endothelin-1 (ET-1) levels are elevated in diabetes, but the molecular components of the enzymatic activation of ET-1 in the vasculature remains unknown. Furthermore, the distribution of ET receptors favors a contractile phenotype in African Americans with diabetes. Whether there is any difference in local ET-1 activation in this population is unknown. This study examined the expression and activity of ET converting enzyme-1 subisoforms (ECE-1) in the internal mammary artery specimens obtained from patients undergoing coronary artery bypass grafting. The study groups included African-American (AA) and Caucasian (CA), nondiabetic (ND) and diabetic (D) patients: AAND N = 10, CAND N = 9, AAD N = 9, and CAD N = 11. The expression of ECE-1 a, ECE-1 b and ECE-1c subisoforms was studied by RT-PCR. ECE-1 a was upregulated 2- and 4-fold in the CAD and MD groups, respectively (P < .05). In African-American patient groups, ECE-1 activity (fmol/ mg protein.h) was augmented from 2,804 +/- 185 in nondiabetic tissue samples to 6,857 +/- 393 in the diabetic tissue (P < .05). There was a similar increase in the CAD group, which did not significantly differ from AA diabetics. ECE-1 inhibitors, phosphoramidon and FR-901533, inhibited vascular ECE-1 activity by more than 80%. While neutral endopeptidase (NEP) and matrix metalloproteinase-2 (MMP-2) are able to process big ET-1, inhibitors of NEP (thiorphan) and MMP (batimistat) did not affect ECE-1 activity. In conclusion, the enzymatic pathway essential for generating vascular ET-1 is activated in the vasculature of both AA and CA diabetic patients and this activation is highly specific for ECE-1.
ISSN:1049-510X