As the global burden of cardiovascular disease (CVD) rises, public health-related interventions aimed at prevention of heart disease have gained medical attention. Clinical research reports that exercise is a protective risk factor associated with CVD and that clinicians need to provide exercise recommendations to patients. Nevertheless, physical inactivity remains a public health problem. In certain populations, like firefighters (FF), increased risk of CVD is especially concerning. The workload FF face is extreme, 50% of line-of-duty deaths (LODD) in FF are cardiac-related, and research on the volunteer FF population is scarce. Government regulations do not require volunteer FF companies to have fitness testing or programming, so exercise intervention studies are necessary to improve the burden of CVD risk in this population. Therefore, this study examined the effects of a 4-week exercise circuit training (CT) intervention on vascular health and fitness in volunteer FF (N = 27) from the Philadelphia PA area compared to a control group of Non-FF (N = 25). Carotid artery intima-media thickness (IMT), brachial artery flow-mediated dilation (FMD), augmentation index, and pulse pressure (PP), brachial and central blood pressure (BP) and fitness were measured pre- and post- intervention. Overall, volunteer FF had more significant improvements (p < 0.05) in vascular health measures (FMD, IMT, and PP). In both groups, we also found that brachial and central BP decreased with exercise. We show that a 4 week CT program can improve vascular structure and function in the volunteer FF population, suggesting that clinicians may be able to reduce or prevent cardiac LODD by exercise.

Cystic fibrosis (CF) is a genetic disorder associated with vascular endothelial dysfunction. Nitric oxide (NO) plays a major role in maintaining vascular function, and tetrahydrobiopterin (BH4) is a critical determinant of NO bioavailability. Thus the purpose of this study was to investigate the effects of oral administration of BH4 on endothelial function in patients with CF. Twenty-nine patients with CF (18 ± 8 yr old) and 29 healthy matched controls were recruited. Patients with CF participated in a randomized trial where they received a 5 mg/kg dose of oral BH4 (BH4-5; n = 17) or a 20 mg/kg dose of oral BH4 (BH4-20; n = 12). On a separate visit, a subset of patients from each group was retested following a placebo (PLC; n = 9). Brachial artery flow-mediated dilation (FMD) was used to evaluate vascular endothelial function, and a plasma sample was obtained before and 3 h after treatment. Cultured endothelial cells were treated with plasma to assess NO bioavailability. Baseline FMD was lower in patients compared with controls (5.7 ± 3.4 vs. 8.4 ± 3.5%, respectively, P = 0.005). No change in FMD was observed following PLC or BH4-5 (∆FMD: −0.8 ± 1.9% and −0.5 ± 2.5%; P = 0.273 and 0.132, respectively). Treatment with BH4-20, however, resulted in significant improvements in FMD (∆FMD: 1.1 ± 1.4%) compared with BH4-5 ( P = 0.023) and PLC ( P = 0.017). Moreover, BH4-20 significantly decreased endothelial cell superoxide production and increased NO production. These data suggest that a single oral dose of BH4 at 20 mg/kg improves vascular endothelial function in patients with CF, likely via increased endothelial NO synthase coupling. These findings support the hypothesis that loss of BH4 bioactivity contributes, in part, to endothelial dysfunction in patients with CF. NEW & NOTEWORTHY For the first time, the present study documents that a single dose of oral BH4 can improve vascular endothelial function in patients with cystic fibrosis (CF), and our in vitro data suggest this is via decreasing uncoupled nitric oxide. These data provide insight into the important role of BH4 bioactivity in vascular dysfunction and provide the foundation for further investigation into the chronic effects of BH4 treatment in patients with CF.

Smoking increases systemic inflammation and circulating endothelin-1 (ET-1), both of which contribute to an elevated risk of cardiovascular disease (CVD). The present study sought to test the hypothesis that a 12-week smoking cessation intervention would contribute to a long-term reduction in circulating ET-1, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). 30 individuals participated in a 12-week evidence-based smoking cessation program at Augusta University. Serum cotinine, plasma inflammatory cytokines, and plasma ET-1 were determined at baseline, immediately after the 12-week cessation program (end of treatment, EOT), and 12-months (12M) following the cessation program. Serum cotinine was significantly reduced (p < 0.001) at EOT and 12M following the smoking cessation program. Compared to BL (7.0 ± 1.6 pg/mL), TNF-α was significantly reduced at EOT (6.3 ± 1.5 pg/mL, p = 0.001) and 12M (5.2 ± 2.7 pg/mL, p < 0.001). ET-1 was significantly lower at EOT (1.9 ± 0.6 pg/mL, p = 0.013) and at 12M (2.0 ± 0.8 pg/mL, p = 0.091) following smoking cessation compared with BL (2.3 ± 0.6 pg/mL). BL concentrations of cotinine were significantly associated with basal ET-1 (r = 0.449, p = 0.013) and the change in cotinine at 12M following smoking cessation was significantly associated with the change in plasma ET-1 at 12M (r = 0.457, p = 0.011). Findings from the present pilot investigation demonstrate that a 12-week smoking cessation program reduces circulating concentrations of ET-1 and TNF-α for at least a year. The reduction in serum cotinine was associated with the decrease in circulating ET-1. The attenuation in ET-1 and inflammation may in part, contribute to the lower risk of CVD that is observed with smoking cessation.