Abstract-The activation of the sympathetic nervous system is a common feature of arterial hypertension and other cardiovascular diseases. This activation might be dependent on an altered baroreflex control of vascular resistance of which the inhibitory response on sympathetic activity appears impaired. The aim of the study was to monitor during the natural course of arterial hypertension in spontaneously hypertensive (SHR) and age-matched Wistar Kyoto (WKY) rats (5, 16, 30, and 54 weeks of age) the peripheral sympathetic activity expressed as interstitial norepinephrine (NE) release and as tyrosine hydroxylase (TH) activity, the rate-limiting enzyme of NE synthesis, in the differently baroreflexcontrolled subcutaneous adipose tissues and skeletal muscles. Blood pressure and plasma NE in SHR were similar to WKY at 5 weeks of age but increased at all other ages. Body weight was similar in both 5-week-old rats but reduced in SHR at all other ages. The interstitial NE levels were greater in both SHR tissues at all ages as compared with WKY. In adipose tissue of SHR, TH activity was higher at all ages as compared with WKY, whereas TH activity in skeletal muscle was higher only after the development of hypertension. These data show that in both SHR tissues, an increase of interstitial NE release is always present during its lifespan. This suggests that increased sympathetic activation in the SHR model is not specific to baroreflex-controlled tissues such as skeletal muscle but involves also subcutaneous adipose tissue, the sympathetic efferents of which are independent from baroreflexes.

ObjectiveAmong patients with Coronavirus disease 2019 (COVID-19), coronary artery disease (CAD) has been identified as a high-risk condition. We aimed to assess the clinical outcomes and mortality among patients with COVID-19 according to CAD status.MethodsWe retrospectively analysed data from patients with COVID-19 admitted to the Cremona Hospital (Lombardy region, Italy) between February and March 2020. The primary outcome was all-cause mortality. CAD was defined as a history of prior myocardial infarction (MI), prior percutaneous coronary intervention (PCI), prior coronary artery bypass grafting (CABG) or CAD that was being medically treated.ResultsOf 1252 consecutive patients with COVID-19, 124 (9.9%) had concomitant CAD. Patients with CAD were older and had a higher prevalence of comorbidities compared with those without CAD. Although patients with CAD had a higher risk of all-cause mortality than patients without CAD (HR 3.01, 95% CI 2.27 to 3.99), this difference was no longer significant in the adjusted model (HR 1.14, 95% CI 0.79 to 1.63). Results were consistent among patients with prior MI (adjusted HR (aHR) 0.87, 95% CI 0.54 to 1.41), prior PCI (aHR 1.10, 95% CI 0.75 to 1.62), prior CABG (aHR 0.91, 95% CI 0.45 to 1.82), or CAD medically treated (aHR 0.84, 95% CI 0.29 to 2.44). Multivariable analysis showed that age (aHR per 5 year increase 1.62, 95% CI 1.53 to 1.72) and female sex (aHR 0.63, 95% CI 0.49 to 0.82) were the only two independent correlates of mortality.ConclusionPatients with COVID-19 and CAD have an exceedingly higher risk of mortality, which is mainly attributable to the burden of comorbidities rather than to a direct effect of CAD per se.

Abstract-Certain forms of experimental hypertension are characterized by organ-specific alterations of catecholaminergic pathways. The purpose of this study was to evaluate, in the same awake and freely moving normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) before and after the development of arterial hypertension, the norepinephrine (NE) turnover and, in particular, the neuronal NE reuptake activity that ends its effects once released from nerve terminals, in subcutaneous adipose tissue and in skeletal muscle, whose sympathetic efferents are respectively independent or dependent from baroreflexes. Plasma and tissue interstitial NE and 3,4-dihydroxyphenylethylene glycol (DHPG), its major deaminated metabolite, were measured before and after blockade of NE reuptake by tissue perfusion of desipramine through microdialysis probes. Arterial pressure and plasma NE in SHR were similar to those in WKY at 5 weeks of age but increased at 16 weeks of age. In contrast, plasma DHPG was already higher in young SHR. Basal interstitial NE and DHPG were increased in both tissues of young and old SHR compared with age-matched WKY. Desipramine induced a higher rise of interstitial NE in SHR of both ages, with a lesser increase in the skeletal muscle of old compared with young SHR. These results indicate an increased NE turnover in prehypertensive and hypertensive SHR in both baroreflex-dependent and -independent tissues, not shown by plasma NE levels in young SHR. In the skeletal muscle, where sympathetic efferents are baroreflex dependent, the reduced interstitial NE reuptake contributes to the higher availability of interstitial NE for postsynaptic effects in old SHR. Key Words: muscle, skeletal Ⅲ adipose tissue Ⅲ nervous system, sympathetic Ⅲ norepinephrine Ⅲ rats, inbred SHR A bnormalities of the central neural mechanisms regulating peripheral sympathetic outflow and catecholamine metabolism after the release of the neurotransmitter from the nerve endings have been described in the development of hypertension in humans 1,2 and in spontaneously hypertensive rats (SHR), 3,4 the animal model of essential hypertension most used. In SHR tissues, age-related differences have been reported in the enzymes implicated in the synthesis (such as tyrosine hydroxylase and dopamine ␤-hydroxylase) and metabolism (such as monoamine oxidase and catechol-o-methyltransferase) of norepinephrine (NE), which has been found to be higher in resistance arteries 5 but normal in the heart in the early phases of hypertension development, with an inverse relationship in adult rats. 6 -9 Neuronal uptake of NE, the active mechanism responsible for removing NE from the synaptic cleft once released from the nerve terminal, 10 has been found to be normal in cardiac and vascular tissue, 11,12 increased in the kidney and skeletal muscle of young SHR, 4 but reduced in the heart 13,14 and kidney 4 and increased in resistance arteries 15,16 of adult SHR. Most of these data on NE turnover are obtained from in vitro or ex vivo tissue st...

Introduction Most of the drugs associations that have been used to treat patients with SARS-CoV-2 infection increase the risk of prolongation of the corrected QT interval (QTc). Objective To evaluate the effects of an association therapy of hydroxychloroquine (HY) plus ritonavir/darunavir (RD) or azithromycin (AZ) on QTc intervals. Methods At the beginning of COVID-19 pandemic patients admitted to our hospital were treated with the empiric association of HY/RD; one week later the therapeutic protocol was modified with the combination of HY/AZ. Patients underwent an ECG at baseline, then 3 and 7 days after starting therapy. We prospectively enrolled 113 patients (61 in the HY/RD group-52 in the HY/AZ group). Results A significant increase in median QTc was reported after seven days of therapy in both groups: from 438 to 452 ms in HY/RD patients; from 433 to 440 ms in HY/AZ patients (p = 0.001 for both). 23 patients (21.2%) had a QTc > 500 ms at 7 days. The risk of developing a QTc > 500 ms was greater in patients with prolonged baseline QTc values (≥ 440 ms for female and ≥ 460 ms for male patients) (OR 7.10 (95% IC 1.88-26.81); p = 0.004) and in patients with an increase in the QTc > 40 ms 3 days after onset of treatment (OR 30.15 (95% IC 6.96-130.55); p = 0.001). One patient per group suffered a malignant ventricular arrhythmia. Conclusion Hydroxychloroquine with both ritonavir/darunavir or azithromycin therapy significantly increased the QTcinterval at 7 days. The risk of developing malignant arrhythmias remained relatively low when these drugs were administered for a limited period of time.

In prehypertensive SHR, left ventricular hypertrophy is associated with adrenergic and nitrosative imbalance. Early superoxide dismutase mimetic treatment in SHR effectively reduces higher myocardial ONOO generation, sympathetic activation, and heart rate without affecting the development of myocardial hypertrophy.