Plasma levels of cyclic GMP and endothelin in postmenopausal women with unstable coronary artery disease

Effects of emissions from different type of residential heating upon cyclic guanosine monophosphate (cGMP) in blood platelets of residents

We hypothesized that different types of residential heating would be associated with different levels of indoor carbon monoxide (CO) and further that this might result in a differential in the concentration of cyclic 3':5' guanosine monophosphate (cGMP) in blood platelets in exposed residents. Individuals, who were recruited from homes using different fuel for heating, donated a venous blood sample in the winter and in the summer. In the winter the median blood platelet cGMP value for the group using liquid propane gas (LPG) was 65% higher than for the group using piped natural gas for heating (p <0.001). Also in the group using LPG, the median concentration of cGMP in the winter was 39% higher than the summer median (p < 0.003). The mean indoor concentrations of CO were measured over a period of 1 week during the winter and were <1 ppm. We conclude that observed differences were associated with emissions from different types of heating but that CO exposure alone is too low to explain these.

Serum biomarker measurements of endothelial function and oxidative stress after daily dosing of sildenafil in type 2 diabetic men with erectile dysfunction

PURPOSE

We investigated changes in serum biomarkers of vascular function after short-term, continuous sildenafil dosing in men with type 2 diabetes with erectile dysfunction.

MATERIALS AND METHODS

Men with erectile dysfunction associated with type 2 diabetes mellitus were randomized to receive continuous, daily sildenafil (50 mg for 1 week run-in and 100 mg for 3 weeks) (148), or placebo (144) for 4 weeks (phase I) and then sildenafil (25, 50 or 100 mg) on demand for 12 weeks (phase II). Blood draws at baseline and after phases I and II were analyzed for cyclic guanosine monophosphate (endothelial function marker), 8-isoprostane (oxidative stress marker), and interleukin-6 and interleukin-8 (inflammatory cytokines). Primary and secondary erectile function outcome variables were affirmative responses on Sexual Encounter Profile question 3 (ability to maintain erection sufficient for sexual intercourse) and Erection Hardness Score, respectively.

RESULTS

Serum cyclic guanosine monophosphate levels were increased in the sildenafil group relative to the placebo group at 4 (p <0.01) and 16 (p <0.05) weeks, correlating with affirmative responses to Sexual Encounter Profile question 3 at the 4-week interval only (p <0.05). Serum 8-isoprostane levels were decreased to a nonsignificant degree in the sildenafil group at 4 weeks with no further change at 16 weeks, whereas interleukin-6 and interleukin-8 levels were unchanged at either interval, and these levels were unassociated with erectile function outcomes.

CONCLUSIONS

These data suggest that short-term, continuous sildenafil treatment causes systemic endothelial function to be enhanced and remain so for a duration after its discontinuation. However, they do not indicate any influence of this treatment on systemic oxidative stress or inflammation, or an effect on long-term erectile function improvement.

Markers of hypercoagulation and von Willebrand factor in postmenopausal women with unstable coronary artery disease. Discriminatory ability regarding unstable coronary artery disease and coronary atherosclerosis using receiver operating characteristics

OBJECTIVES

Many women with typical anginal chest pain have normal coronary angiograms. The pathogenetic mechanisms behind the chest pain in these patients are unknown but may be due to increased thrombogenicity. We evaluated markers of hypercoagulation and thrombosis in women with clinical signs of unstable coronary artery disease (CAD).

METHODS AND RESULTS

A total of 158 patients with unstable CAD and 101 controls were examined: 16% of the patients had normal vessels and 84% had coronary atherosclerosis at coronary angiography. Mean plasma concentrations of von Willebrand factor antigen, soluble fibrin (SF), thrombin-antithrombin complex and D-dimer were significantly higher, whereas there was no difference regarding prothrombin fragment 1+2 between patients and controls. Patients with coronary atherosclerosis had higher mean plasma levels for most variables compared with those with normal coronary vessels, although only significantly higher for SF. D-Dimer was significantly higher in patients with normal coronary vessels compared with the control group. Although multivariate analyses showed strong significant correlations of the haemostatic variables to the diagnosis of unstable CAD, receiver operating characteristics (ROC) revealed that none of the variables represented high diagnostic accuracy in separating patients with unstable CAD. Likewise, none of the variables was particularly good at identifying coronary atherosclerosis.

CONCLUSION

Our results are in favour of a hypercoagulable state in postmenopausal women with unstable CAD and coronary atherosclerosis, whereas this does not seem to be the case in patients with normal vessels. ROC revealed no variable to be particularly clinically useful in separating patients from controls or patients from those without coronary atherosclerosis.

Effects of short- and long-term exercise on urinary cGMP excretion in healthy subjects and in patients with coronary artery disease

The possibility that systemic formation of cyclic guanosine monophosphate (cGMP) could reflect the level of cardiovascular fitness was investigated. The relations between physical activity and systemic formation of cGMP were evaluated in healthy volunteers and in patients with coronary artery disease (CAD). No significant differences were observed in the basal urinary excretion of cGMP in highly trained runners, sedentary subjects, and in patients with CAD, despite the large differences in aerobic exercise training between groups. In addition, the basal levels of cGMP in CAD patients failed to increase after a 12-week cardiac rehabilitation program. Short-term exercise, on the other hand, was associated with significant increases in urinary cGMP excretion. A 42-km marathon increased urinary cGMP excretion by 272%. The 15-km race increased urinary cGMP excretion by 330%. In CAD patients, 30 min of supervised exercise on a treadmill, at 80% of patient's maximal heart rate, induced a 60% increase in urinary cGMP, which returned to preexercise levels 90 min after termination of the exercise. Completion of the 12-week cardiac rehabilitation program improved exercise capacity and the magnitude of increase in cGMP levels induced by short-term treadmill exercise. Our findings suggest that cGMP increases during and shortly after short-term exercise and that the magnitude of the increase seems dependent on the intensity of the exercise and on physical fitness. Exercise training in healthy subjects and in CAD patients enhanced the amount of cGMP produced during short-term exercise, which might be responsible for some of the protective cardiovascular actions of exercise. The short half-life of cGMP may explain why the basal resting levels of cGMP are not appropriate predictors of a subject's physical fitness.