Vascular insulin response is preserved in non-diabetic patients with coronary artery disease, despite endothelial dysfunction.
BACKGROUND
Patients with coronary artery disease (CAD) are often insulin resistant, a state that predisposes to increased atherosclerosis. Recently, it was suggested that a "vascular insulin resistance" could explain this association, causing endothelial dysfunction and hence atherosclerosis. We therefore studied the vascular insulin response in patients with CAD.


METHODS
Nine non-diabetic patients with documented CAD and 31 lean healthy controls were examined. Forearm blood flow was measured by venous occlusion plethysmography. Dose-response studies of acetylcholine (ACh) and sodium nitroprusside (SNP) elicited endothelium-dependent and -independent vasodilation and were repeated during intra-arterial insulin infusion.


RESULTS
Patients were insulin resistant as determined by HOMA index. Insulin infusion resulted in high physiological levels of insulin in the forearm without systemic effects. Patients had a reduced ACh response but insulin infusion increased the ACh response equally in patients and controls (a mean increase of 74+/-37 vs 57+/-24%, patients vs controls, p=0.12). A minor increase of the SNP response was also noted during insulin infusion.


CONCLUSIONS
Vascular insulin response is intact in non-diabetic CAD patients in spite of insulin resistance and endothelial dysfunction.
Ihlemann
Nikolaj
N
Department of Cardiology, Bispebjerg University Hospital, Copenhagen, Denmark. nihl@heart.dk
Rask-Madsen
Christian
C
Køber
Lars
L
Torp-Pedersen
Christian
C
D000109:Acetylcholine / Q000008:administration & dosage; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D003324:Coronary Artery Disease / Q000188:drug therapy* / Q000503:physiopathology*; D003920:Diabetes Mellitus / Q000188:drug therapy* / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology*; D005260:Female; D005542:Forearm / Q000098:blood supply; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000008:administration & dosage; D012039:Regional Blood Flow / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage
D015415:Biomarkers; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D014665:Vasodilator Agents; D009599:Nitroprusside; D000109:Acetylcholine