Validating the accuracy of a multifunctional smartwatch sphygmomanometer to monitor blood pressure

BACKGROUND Hypertension is the most modifiable factor associated with cardiovascular events and complications.The conventional blood pressure(BP) meter method is simple but is limited in terms of real-time monitoring abnormal BP.Therefore,the development of a multifunction smartwatch(HUAWEI WATCH D) sphygmomanometer could significantly improve integrated BP monitoring.METHODS We enrolled 361 subjects from Chinese PL A General Hospital,Beijing,China to validate the accuracy of the smartwatch versatile sphygmomanometer using ISO 81060-2:2018.Resting and ambulatory BP accuracy of the smartwatch were compared with gold standard clinical sphygmomanometers using ISO 81060-2:2018 guidelines,the accuracy of 24 h systolic blood pressure(SBP) circadian rhythm monitoring,and diurnal high SBP alert for this smartwatch were assessed using a confusion matrix approach.Additionally,we analyzed online users of different ages for compliance.RESULTS Eighty-five subjects underwent resting BP measurements;the mean resting BP differences between two devices were-0.683±6.203 mmHg(SBP)(P=0.723) and 1.628±5.028 mmHg(diastolic blood pressure,DBP)(P=0.183).In 35 subjects’ ambulatory BP measurements,the mean differences of ambulatory BP were-1.943±5.475 mmHg(SBP)(P=0.923) and 3.195±5.862 mmHg(DBP)(P=0.065).All data complied with ISO 81060-2:2018 guidelines(mean ≤±5 mmHg and standard deviation ≤±8 mmHg) with no significant differences.Positive predictive values(PPV) of resting SBP and DBP were 0.635 and 0.671,respectively.The PPV of ambulatory SBP and DBP were 0.686.Also,24 h SBP circadian rhythm monitoring was performed in 107 subjects:accuracy=0.850,specificity=0.864,precision/PPV=0.833,sensitivity=0.833,and F1-measure(F1)=0.833.The accuracy,specificity,precision,sensitivity,and F1 values in 85 subjects undergoing diurnal high SBP alerting were 0.858,0.876,0.706,0.809,and 0.754,respectively.CONCLUSIONS When compared with the gold standard clinical sphygmomanometer,smartwatch results were consistent and accurate.Online user feedback showed that elderly individuals cared more about BP monitoring accuracy,with better compliance.

Local Structures and Chemical Properties of Deprotonated Arginine

The potential energy surface of gaseous deprotonated arginine has been systematically in- vestigated by first principles calculations. At the B3LYP/6-31G（d） level, apart from the identification of several stable local structures, a new global minimum is located which is about 6.56 k J/tool more stable than what has been reported. The deprotonated arginine molecule has two distinct forms with the deprotonation at the carboxylate group （COO-）. These two forms are bridged by a very high energy barrier and possess very different IR spectral profiles. Our calculated proton dissociation energy and gas-phase acidity of argi- nine molecule are found to be in good agreement with the corresponding experimental results. The predicted geometries, dipole moments, rotational constants, vertical ionization energies and IR spectra of low energy conformers will be useful for future experimental measurements.

Blockade of c-Src Within the Paraventricular Nucleus Attenuates Inflammatory Cytokines and Oxidative Stress in the Mechanism of the TLR4 Signal Pathway in Salt-Induced Hypertension

Toll-like receptor 4 (TLR4) and cellular Src (cSrc) are closely associated with inflammatory cytokines and oxidative stress in hypertension, so we designed this study to explore the exact role of c-Src in the mechanism of action of the TLR4 signaling pathway in salt-induced hypertension. Salt-sensitive rats were given a high salt diet for 10 weeks to induce hypertension. This resulted in higher levels of TLR4, activated c-Src, pro-inflammatory cytokines, oxidative stress, and arterial pressure. Infusion of a TLR4 blocker into the hypothalamic paraventricular nucleus (PVN) decreased the activated c-Src, while microinjection of a c-Src inhibitor attenuated the PVN levels of nuclear factor-kappa B, pro-inflammatory cytokines, and oxidative stress. Our findings suggest that a longterm high-salt diet increases TLR4 expression in the PVN and this promotes the activation of c-Src, which upregulates the expression of pro-inflammatory cytokines and results in the overproduction of reactive oxygen species.Therefore, inhibiting central c-Src activity may be a new target for treating hypertension.

Chronic Intracerebroventricular Infusion of Metformin Inhibits Salt-Sensitive Hypertension via Attenuation of Oxidative Stress and Neurohormonal Excitation in Rat Paraventricular Nucleus

Metformin(MET), an antidiabetic agent, also has antioxidative effects in metabolic-related hypertension.This study was designed to determine whether MET has anti-hypertensive effects in salt-sensitive hypertensive rats by inhibiting oxidative stress in the hypothalamic paraventricular nucleus(PVN). Salt-sensitive rats received a highsalt(HS) diet to induce hypertension, or a normal-salt(NS)diet as control. At the same time, they received intracerebroventricular(ICV) infusion of MET or vehicle for 6 weeks. We found that HS rats had higher oxidative stress levels and mean arterial pressure(MAP) than NS rats. ICV infusion of MET attenuated MAP and reduced plasma norepinephrine levels in HS rats. It also decreased reactive oxygen species and the expression of subunits of NAD(P)H oxidase, improved the superoxide dismutase activity,reduced components of the renin-angiotensin system, and altered neurotransmitters in the PVN. Our findings suggest that central MET administration lowers MAP in saltsensitive hypertension via attenuating oxidative stress,inhibiting the renin-angiotensin system, and restoring the balance between excitatory and inhibitory neurotransmitters in the PVN.

Blockade of Endogenous Angiotensin-(1–7) in Hypothalamic Paraventricular Nucleus Attenuates High Salt-Induced Sympathoexcitation and Hypertension

Angiotensin(Ang)-(1–7) is an important biologically-active peptide of the renin-angiotensin system. This study was designed to determine whether inhibition of Ang-(1–7) in the hypothalamic paraventricular nucleus(PVN) attenuates sympathetic activity and elevates blood pressure by modulating pro-inflammatory cytokines(PICs)and oxidative stress in the PVN in salt-induced hypertension. Rats were fed either a high-salt(8% NaCl) or a normal salt diet(0.3% NaCl) for 10 weeks, followed by bilateral microinjections of the Ang-(1–7) antagonist A-779 or vehicle into the PVN. We found that the mean arterial pressure(MAP), renal sympathetic nerve activity(RSNA), and plasma norepinephrine(NE) were significantly increased in salt-induced hypertensive rats. The high-salt diet also resulted in higher levels of the PICs interleukin-6, interleukin-1 beta, tumor necrosis factor alpha, and monocyte chemotactic protein-1, as well as higher gp91 phoxexpression and superoxide production in the PVN. Microinjection of A-779(3 nmol/50 nL) into the bilateral PVN of hypertensive rats not only attenuated MAP, RSNA, and NE, but also decreased the PICs and oxidative stress in the PVN. These results suggest that the increased MAP and sympathetic activity in salt-induced hypertension can be suppressed by blockade of endogenous Ang-(1–7) in the PVN, through modulation of PICs and oxidative stress.