Paclitaxel chemotherapy and vascular toxicity as assessed by flow-mediated and nitrate-mediated vasodilatation.

BACKGROUND: Antitumor activity of paclitaxel is based on promotion of abnormal microtubule (MT) assembly but it is also considered to have significant pro-inflammatory and anti-angiogenic effects in vivo and thus may cause vascular dysfunction. METHODS: We studied 27 women treated with paclitaxel-containing combinations for breast or ovarian cancer. The control group was represented by 10 women with carcinoma of the uterine cervix who received low doses of weekly cisplatin as radiation sensitizer. We measured endothelial-dependent flow-mediated dilatation (FMD) and nitrate-mediated dilatation (NMD) of the right brachial artery by ultrasonography, as well as levels of the inflammatory cytokines TNF-alpha and IL-6 before and after chemotherapy. RESULTS: Patients who received paclitaxel and an anthracycline had the most marked reduction in both FMD (p=0.005) and NMD (p=0.027). A significant reduction in FMD was also observed in patients treated with weekly paclitaxel (p=0.045), whereas NMD was not affected (p=0.421). Although TNF-alpha and IL-6 levels were different among chemotherapy groups after treatment, no significant differences were observed between levels of both markers before and after chemotherapy. CONCLUSION: Treatment with paclitaxel-containing combinations impairs endothelial function in vivo but endothelial function deterioration is not related to the serum levels of inflammation markers.

Improvement of vascular endothelial function using the oral endothelin receptor antagonist bosentan in patients with systemic sclerosis.

OBJECTIVE: Increased endothelin activity may play a role in the pathogenesis of vascular injury, a primary feature of systemic sclerosis (SSc; scleroderma). Our goal was to test the hypothesis that treatment with the oral endothelin receptor antagonist bosentan might improve vascular endothelial function in SSc patients. METHODS: A 4-week, prospective, parallel-group study compared 12 SSc patients who did not receive bosentan treatment with 12 patients who did receive treatment (125 mg/day) for pulmonary hypertension and/or digital ulcers. There were no differences in demographic and clinical characteristics or medications between the 2 groups. Baseline endothelial dysfunction was documented by decreased brachial artery ultrasound-derived flow-mediated dilation (FMD%; <5.5). Pulse wave analysis, venous occlusion plethysmography, and measurement of serum vascular markers were performed in parallel. RESULTS: FMD%, the main end point, increased significantly from a mean +/- SD of 3.1 +/- 1.3% to 8.4 +/- 2.6% after 4 weeks of bosentan treatment (P < 0.001, compared with a change from 2.4 +/- 1.6% to 2.4 +/- 2.2% in control patients). Arterial blood pressure, endothelium-independent vascular function, augmentation index, peripheral flow reserve, as well as circulating intercellular adhesion molecule 1, E-selectin, vascular endothelial growth factor, and endothelin 1 were not significantly affected by bosentan treatment. In patients continuously treated for 4 months, during which the dosage of bosentan remained at 125 mg/day (n = 5) or increased to 250 mg/day (n = 5), the 4-week results remained unchanged. CONCLUSION: Small doses of bosentan improve endothelial function without affecting hemodynamic parameters or endothelial activation-related processes, thus supporting a direct, reversible effect of endothelin in SSc-associated vascular injury. A long-term, controlled trial to examine the potentially global clinical benefit of endothelin receptor blockade in patients with early SSc may be warranted.