Background Hypertension is assumed to be asymptomatic. Yet, clinically significant nocturia (≥2 nightly voids) constitutes a putative symptom of uncontrolled hypertension. Black men with hypertension may be prone to nocturia because of blunted nocturnal blood pressure ( BP ) dipping, diuretic drug use for hypertension, and comorbidity that predisposes to nocturia. Here, we test the hypothesis that nocturia is a common and potentially reversible symptom of uncontrolled hypertension in black men. Methods and Results We determined the strength of association between nocturia (≥2 nightly voids) and high BP (≥135/85 mm Hg) by conducting in‐person health interviews and measuring BP with an automated monitor in a large community‐based sample of black men in their barbershops. Because nocturia is prevalent and steeply age‐dependent after age 50 years, we studied men aged 35 to 49 years. Among 1673 black men (mean age, 43±4 years [ SD ]), those with hypertension were 56% more likely than men with normotension to have nocturia after adjustment for diabetes mellitus and sleep apnea (adjusted odds ratio, 1.56; 95% CI , 1.25–1.94 [ P <0.0001]). Nocturia prevalence varied by hypertension status, ranging from 24% in men with normotension to 49% in men whose hypertension was medically treated but uncontrolled. Men with untreated hypertension were 39% more likely than men with normotension to report nocturia ( P =0.02), whereas men whose hypertension was treated and controlled were no more likely than men with normotension to report nocturia ( P =0.69). Conclusions Uncontrolled hypertension was an independent determinant of clinically important nocturia in a large cross‐sectional community‐based study of non‐Hispanic black men aged 35 to 49 years. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unqiue identifier: NCT 02321618.
Hookah (water pipe) smoking is a major new understudied epidemic affecting youth. Because burning charcoal is used to heat the tobacco product, hookah smoke delivers not only nicotine but also large amounts of charcoal combustion products, including carbon-rich nanoparticles that constitute putative coronary vasoconstrictor stimuli and carbon monoxide, a known coronary vasodilator. We used myocardial contrast echocardiography perfusion imaging with intravenous lipid shelled microbubbles in young adult hookah smokers to determine the net effect of smoking hookah on myocardial blood flow. In 9 hookah smokers (age 27 – 5 years, mean – SD), we measured myocardial blood flow velocity (β), myocardial blood volume (A), myocardial blood flow (A × β) as well as myocardial oxygen consumption (MVO2) before and immediately after 30 minutes of ad lib hookah smoking. Myocardial blood flow did not decrease with hookah smoking but rather increased acutely (88 – 10 to 120 – 19 a.u./s, mean – SE, p = 0.02), matching a mild increase in MVO2 (6.5 – 0.3 to 7.6 – 0.4 ml·minute−1, p <0.001). This was manifested primarily by increased myocardial blood flow velocity (0.7 – 0.1 to 0.9 – 0.1 second−1, p = 0.01) with unchanged myocardial blood volume (133 – 7 to 137 – 7 a.u., p = ns), the same pattern of coronary microvascular response seen with a low-dose β-adrenergic agonist. Indeed, with hookah, the increased MVO2 was accompanied by decreased heart rate variability, an indirect index of adrenergic overactivity, and eliminated by β-adrenergic blockade (i.v. propranolol). In conclusion, nanoparticle-enriched hookah smoke either is not an acute coronary vasoconstrictor stimulus or its vasoconstrictor effect is too weak to overcome the physiologic dilation of coronary microvessels matching mild cardiac β-adrenergic stimulation.
Key pointsr Dystrophin deficiency disrupts sarcolemmal targeting of neuronal nitric oxide synathase, resulting in functional muscle ischaemia.r Chronic treatment of dystrophic mice with an inorganic nitric oxide (NO) donor alleviates this ischaemia and improves many features of the dystrophic phenotype.r The present study translates this preclinical work by showing that a single oral dose of sodium nitrate,which serves as a NO donor when reduced to circulating nitrite by the commensal bacteria in the oral cavity, alleviates functional muscle ischaemia and restores normal blood flow regulation in human patients with dystrophinopathy.r The results of the present study further support the mechanistic hypothesis that circulating nitrite serves as an alternative NO donor when reduced by deoxyhaemoglobin and/or deoxymyoglobin in exercising muscle.Abstract Becker muscular dystrophy (BMD) is a progressive X-linked muscle wasting disease for which there is no treatment. BMD is caused by in-frame mutations in the gene encoding dystrophin, a structural cytoskeletal protein that also targets other proteins to the sarcolemma. Among these is neuronal nitric oxide synthase mu (nNOSμ), which requires specific spectrin-like repeats (SR16/17) in dystrophin's rod domain and the adaptor protein α-syntrophin for sarcolemmal targeting. When healthy skeletal muscle is exercised, sarcolemmal nNOSμ-derived nitric oxide (NO) attenuates α-adrenergic vasoconstriction, thus optimizing perfusion. In the mdx mouse model of dystrophinopathy, this protective mechanism (functional sympatholysis) is defective, resulting in functional muscle ischaemia. Treatment with a NO-donating non-steroidal anti-inflammatory drug (NSAID) alleviates this ischaemia and improves the murine dystrophic phenotype. In the present study, we report that, in 13 men with BMD, sympatholysis is defective mainly in patients whose mutations disrupt sarcolemmal targeting of nNOSμ, with the vasoconstrictor response measured as a decrease in muscle oxygenation (near infrared spectroscopy) to reflex sympathetic activation. Then, in a single-arm, open-label trial in 11 BMD patients and a double-blind, placebo-controlled cross-over trial in six patients, we show that acute treatment with oral sodium nitrate, an inorganic NO donor without a NSIAD moiety, restores sympatholysis and improves post-exercise hyperaemia (Doppler ultrasound). By contrast, sodium nitrate improves neither sympatholysis, nor hyperaemia in healthy controls. Thus, a simple NO donor recapitulates the vasoregulatory actions of sarcolemmal nNOS in BMD patients, and constitutes a putative novel therapy for this disease.
OBJECTIVES The authors investigated ideal acoustic conditions on a clinical scanner custom-programmed for ultrasound (US) cavitation-mediated flow augmentation in preclinical models. We then applied these conditions in a first-inhuman study to test the hypothesis that contrast US can increase limb perfusion in normal subjects and patients with peripheral artery disease (PAD).BACKGROUND US-induced cavitation of microbubble contrast agents augments tissue perfusion by convective shear and secondary purinergic signaling that mediates release of endogenous vasodilators.METHODS In mice, unilateral exposure of the proximal hindlimb to therapeutic US (1.3 MHz, mechanical index 1.3) was performed for 10 min after intravenous injection of lipid microbubbles. US varied according to line density (17, 37, 65 lines) and pulse duration. Microvascular perfusion was evaluated by US perfusion imaging, and in vivo adenosine triphosphate (ATP) release was assessed using in vivo optical imaging. Optimal parameters were then used in healthy volunteers and patients with PAD where calf US alone or in combination with intravenous microbubble contrast infusion was performed for 10 min. RESULTSIn mice, flow was augmented in the US-exposed limb for all acoustic conditions. Only at the lowest line density was there a stepwise increase in perfusion for longer (40-cycle) versus shorter (5-cycle) pulse duration. For higher line densities, blood flow consistently increased by 3-fold to 4-fold in the US-exposed limb irrespective of pulse duration. High line density and long pulse duration resulted in the greatest release of ATP in the cavitation zone.Application of these optimized conditions in humans together with intravenous contrast increased calf muscle blood flow by >2-fold in both healthy subjects and patients with PAD, whereas US alone had no effect.CONCLUSIONS US of microbubbles when using optimized acoustic environments can increase perfusion in limb skeletal muscle, raising the possibility of a therapy for patients with PAD.
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