Vascular endothelium and inflammatory process, in patients with combined Type 2 diabetes mellitus and coronary atherosclerosis: the effects of vitamin C.
OBJECTIVE
Type 2 diabetes mellitus (DM) and coronary artery disease (CAD) are both associated with endothelial dysfunction and elevated oxidative and inflammatory state. We examined the effect of vitamin C on endothelial function and levels of soluble vascular cell adhesion molecule (sVCAM-1), interleukin-6 (IL-6) and tumour necrosis factor (TNF-alpha), in DM patients with or without CAD and in non-diabetic subjects.


METHODS
Thirty-seven patients with DM + CAD, 17 patients with DM without CAD and 21 non-diabetic subjects were divided into groups receiving vitamin C 2 g/day or no anti-oxidant for 4 weeks. Forearm blood flow was determined using venous occlusion gauge-strain plethysmography. Forearm vasodilatory response to reactive hyperemia was considered as index of endothelium-dependent dilation.


RESULTS
Baseline levels of IL-6 and TNF-alpha were significantly higher in patients with DM + CAD compared with patients with DM (P < 0.01) or non-diabetic subjects (P < 0.01). IL-6 and TNF-alpha levels were also higher in DM compared with non-diabetic subjects (P < 0.05). sVCAM-1 levels were lower in non-diabetic controls compared with DM + CAD (P < 0.05) or DM (P < 0.05). Reactive hyperaemia was higher in non-diabetic controls compared with DM + CAD (P < 0.001) or DM (P < 0.001). Vitamin C significantly increased reactive hyperaemia only in the DM + CAD group, while it had no effect on serum levels of sVCAM-1, TNF-alpha and IL-6 in any of the groups.


CONCLUSIONS
Type 2 diabetes mellitus is associated with impaired endothelial function and increased levels of TNF-alpha, IL-6 and sVCAM-1, especially in patients with DM and CAD. Vitamin C significantly increased forearm vasodilatory response to reactive hyperaemia only in patients with combined DM and CAD.
Antoniades
C
C
Cardiology Department, Athens University Medical School, Greece.
Tousoulis
D
D
Tountas
C
C
Tentolouris
C
C
Toutouza
M
M
Vasiliadou
C
C
Tsioufis
C
C
Toutouzas
P
P
Stefanadis
C
C
D000975:Antioxidants / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000627:therapeutic use*; D003324:Coronary Artery Disease / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D005542:Forearm / Q000098:blood supply; D006801:Humans; D006940:Hyperemia / Q000097:blood / Q000150:complications / Q000503:physiopathology; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D019010:Vascular Cell Adhesion Molecule-1 / Q000097:blood; D014664:Vasodilation / Q000502:physiology
D000975:Antioxidants; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D001205:Ascorbic Acid