Elevated Interleukin-6 Levels Are Associated With an Increased Risk of QTc Interval Prolongation in a Large Cohort of US Veterans.

BACKGROUND: Although accumulating data indicate that IL-6 (interleukin-6) can promote heart rate-corrected QT interval (QTc) prolongation via direct and indirect effects on cardiac electrophysiology, current evidence comes from basic investigations and small clinical studies only. Therefore, IL-6 is still largely ignored in the clinical management of long-QT syndrome and related arrhythmias. The aim of this study was to estimate the risk of QTc prolongation associated with elevated IL-6 levels in a large population of unselected subjects. METHODS AND RESULTS: An observational study using the Veterans Affairs Informatics and Computing Infrastructure was performed. Participants were US veterans who had an ECG and were tested for IL-6. Descriptive statistics and univariate and multivariate regression analyses were performed to study the relationship between IL-6 and QTc prolongation risk. Study population comprised 1085 individuals, 306 showing normal (<5 pg/mL), 376 moderately high (5-25 pg/mL), and 403 high (>25 pg/mL) IL-6 levels. Subjects with elevated IL-6 showed a concentration-dependent increase in the prevalence of QTc prolongation, and those presenting with QTc prolongation exhibited higher circulating IL-6 levels. Stepwise multivariate regression analyses demonstrated that increased IL-6 level was significantly associated with a risk of QTc prolongation up to 2 times the odds of the reference category of QTc (e.g. QTc >470 ms men/480 ms women ms: odds ratio, 2.28 [95% CI, 1.12-4.50] for IL-6 >25 pg/mL) regardless of the underlying cause. Specifically, the mean QTc increase observed in the presence of elevated IL-6 was quantitatively comparable (IL-6 >25 pg/mL:+6.7 ms) to that of major recognized QT-prolonging risk factors, such as hypokalemia and history of myocardial infarction. CONCLUSIONS: Our data provide evidence that a high circulating IL-6 level is a robust risk factor for QTc prolongation in a large cohort of US veterans, supporting a potentially important arrhythmogenic role for this cytokine in the general population.

Anti-Ro/SSA Antibodies Blocking Calcium Channels as a Potentially Reversible Cause of Atrioventricular Block in Adults.

BACKGROUND: In ∼50% of severe atrioventricular blocks (AVBs) occurring in adults <50 years, the underlying etiology remains unknown. Preliminary evidence from case reports suggests that autoimmunity, specifically the presence of circulating anti-Ro/SSA antibodies in the patient (acquired form), in the patient's mother (late-progressive congenital form), or in both (mixed form), could be involved in a fraction of idiopathic AVBs in adults by possibly targeting the L-type calcium channel (Cav1.2) and inhibiting the related current (ICaL). OBJECTIVES: The purpose of this study was to evaluate whether anti-Ro/SSA antibodies are causally implicated in the development of isolated AVBs in adults. METHODS: Thirty-four consecutive patients with isolated AVB of unknown origin and 17 available mothers were prospectively enrolled in a cross-sectional study. Anti-Ro/SSA antibodies were assessed by fluoroenzyme-immunoassay, immuno-Western blotting, and line-blot immunoassay. Purified immunoglobulin-G (IgG) from anti-Ro/SSA-positive and anti-Ro/SSA-negative subjects were tested on ICaL and Cav1.2 expression using tSA201 and HEK293 cells, respectively. Moreover, in 13 AVB patients, the impact of a short course of steroid therapy on AV conduction was evaluated. RESULTS: Anti-Ro/SSA antibodies, particularly anti-Ro/SSA-52kD, were found in 53% of AVB-patients and/or in their mothers, most commonly an acquired or mixed form (two-thirds of cases) without history of autoimmune diseases. Purified IgG from anti-Ro/SSA-positive but not anti-Ro/SSA-negative AVB patients acutely inhibited ICaL and chronically down-regulated Cav1.2 expression. Moreover, anti-Ro/SSA-positive sera showed high reactivity with peptides corresponding to the Cav1.2 channel pore-forming region. Finally, steroid therapy rapidly improved AV conduction in AVB-patients with circulating anti-Ro/SSA antibodies but not in those without. CONCLUSIONS: Our study points to anti-Ro/SSA antibodies as a novel, epidemiologically relevant and potentially reversible cause of isolated AVB in adults, via an autoimmune-mediated functional interference with the L-type calcium channels. These findings have significant impact on antiarrhythmic therapies by avoiding or delaying pacemaker implantation.

Transient Hypogonadism Is Associated With Heart Rate-Corrected QT Prolongation and Torsades de Pointes Risk During Active Systemic Inflammation in Men.

Background Systemic inflammation and male hypogonadism are 2 increasingly recognized "nonconventional" risk factors for long-QT syndrome and torsades de pointes (TdP). Specifically, inflammatory cytokines prolong, while testosterone shortens the heart rate-corrected QT interval (QTc) via direct electrophysiological effects on cardiomyocytes. Moreover, several studies demonstrated important interplays between inflammation and reduced gonad function in men. We hypothesized that, during inflammatory activation in men, testosterone levels decrease and that this enhances TdP risk by contributing to the overall prolonging effect of inflammation on QTc. Methods and Results We investigated (1) the levels of sex hormones and their relationship with inflammatory markers and QTc in male patients with different types of inflammatory diseases, during active phase and recovery; and (2) the association between inflammatory markers and sex hormones in a cohort of male patients who developed extreme QTc prolongation and TdP, consecutively collected over 10 years. In men with active inflammatory diseases, testosterone levels were significantly reduced, but promptly normalized in association with the decrease in C-reactive protein and interleukin-6 levels. Reduction of testosterone levels, which also inversely correlated with 17-ß estradiol over time, significantly contributed to inflammation-induced QTc prolongation. In men with TdP, both active systemic inflammation and hypogonadism were frequently present, with significant correlations between C-reactive protein, testosterone, and 17-ß estradiol levels; in these patients, increased C-reactive protein and reduced testosterone were associated with a worse short-term outcome of the arrhythmia. Conclusions During systemic inflammatory activation, interleukin-6 elevation is associated with reduced testosterone levels in males, possibly deriving from an enhanced androgen-to-estrogen conversion. While transient, inflammatory hypotestosteronemia is significantly associated with an increased long-QT syndrome/TdP risk in men.

Unravelling Atrioventricular Block Risk in Inflammatory Diseases: Systemic Inflammation Acutely Delays Atrioventricular Conduction via a Cytokine-Mediated Inhibition of Connexin43 Expression.

Background Recent data suggest that systemic inflammation can negatively affect atrioventricular conduction, regardless of acute cardiac injury. Indeed, gap-junctions containing connexin43 coupling cardiomyocytes and inflammation-related cells (macrophages) are increasingly recognized as important factors regulating the conduction in the atrioventricular node. The aim of this study was to evaluate the acute impact of systemic inflammatory activation on atrioventricular conduction, and elucidate underlying mechanisms. Methods and Results We analyzed: (1) the PR-interval in patients with inflammatory diseases of different origins during active phase and recovery, and its association with inflammatory markers; (2) the existing correlation between connexin43 expression in the cardiac tissue and peripheral blood mononuclear cells (PBMC), and the changes occurring in patients with inflammatory diseases over time; (3) the acute effects of interleukin(IL)-6 on atrioventricular conduction in an in vivo animal model, and on connexin43 expression in vitro. In patients with elevated C-reactive protein levels, atrioventricular conduction indices are increased, but promptly normalized in association with inflammatory markers reduction, particularly IL-6. In these subjects, connexin43 expression in PBMC, which is correlative of that measured in the cardiac tissue, inversely associated with IL-6 changes. Moreover, direct IL-6 administration increased atrioventricular conduction indices in vivo in a guinea pig model, and IL-6 incubation in both cardiomyocytes and macrophages in culture, significantly reduced connexin43 proteins expression. Conclusions The data evidence that systemic inflammation can acutely worsen atrioventricular conduction, and that IL-6-induced down-regulation of cardiac connexin43 is a mechanistic pathway putatively involved in the process. Though reversible, these alterations could significantly increase the risk of severe atrioventricular blocks during active inflammatory processes.

Is His-optimized superior to conventional cardiac resynchronization therapy in improving heart failure? Results from a propensity-matched study.

BACKGROUND: His bundle pacing (HBP), alone or optimized in association with coronary sinus pacing (HBP+LV) has recently been proposed as an alternative to conventional cardiac resynchronization therapy (CRT). However, there is lack of controlled studies that assessed clinical outcome. METHODS: We did a single-center, propensity-score matched, case-control study of comparison of HBP and HBP+LV versus conventional CRT in patients with heart failure (HF) and standard indications for CRT. The study group patients were consecutively enrolled in the year 2019. The control group patients were selected, by propensity score matching, among those CRT implantations performed in the years 2015-2018. RESULTS: There were 27 patients in each group. In the active group, 12 (44%) patients received HBP alone and 12 (44%) patients HBP+LV pacing. HBP failed in three (11%) patients. In the control group, conventional CRT was achieved in 26 (96%) patients and failed in one. Paced QRS width was shorter in the active than in the control group (128 ± 18 vs. 148 ± 27 ms, p = .004). During a mean of 9.6 months of follow-up, a composite clinical outcome of death, hospitalization for HF or worsening HF occurred in three (11%) in the active group and in four (15%) in the control group, p = .58. No difference was also observed with softer endpoints: NYHA class (1.9 ± 0.7 vs. 2.1 ± 0.7), subjective improvement (74% vs. 74%) and LV ejection fraction (40.7% vs. 40.7%). CONCLUSION: Compared with conventional CRT, a shorter QRS width can be obtained with HBP alone or in association with coronary sinus pacing but we were unable to show a better clinical outcome. There is urgent need for large, randomized trials.

Proton Pump Inhibitors Directly Block hERG-Potassium Channel and Independently Increase the Risk of QTc Prolongation in a Large Cohort of US Veterans.

[Figure: see text].

Cardiac Arrest Risk During Acute Infections: Systemic Inflammation Directly Prolongs QTc Interval via Cytokine-Mediated Effects on Potassium Channel Expression.

BACKGROUND: During acute infections, the risk of malignant ventricular arrhythmias is increased, partly because of a higher propensity to develop QTc prolongation. Although it is generally believed that QTc changes almost exclusively result from concomitant treatment with QT-prolonging antimicrobials, direct effects of inflammatory cytokines on ventricular repolarization are increasingly recognized. We hypothesized that systemic inflammation per se can significantly prolong QTc during acute infections, via cytokine-mediated changes in K+ channel expression. METHODS: We evaluated (1) the frequency of QTc prolongation and its association with inflammatory markers, in patients with different types of acute infections, during active disease and remission; (2) the prevalence of acute infections in a cohort of consecutive patients with Torsades de Pointes; (3) the relationship between K+ channel mRNA levels in ventricles and peripheral blood mononuclear cells and their changes in patients with acute infection over time. RESULTS: In patients with acute infections, regardless of concomitant QT-prolonging antimicrobial treatments, QTc was significantly prolonged but rapidly normalized in parallel to CRP (C-reactive protein) and cytokine level reduction. Consistently in the Torsades de Pointes cohort, concomitant acute infections were highly prevalent (30%), despite only a minority (25%) of these cases were treated with QT-prolonging antimicrobials. KCNJ2 K+ channel expression in peripheral blood mononuclear cell, which strongly correlated to that in ventricles, inversely associated to CRP and IL (interleukin)-1 changes in acute infection patients. CONCLUSIONS: During acute infections, systemic inflammation rapidly induces cytokine-mediated ventricular electrical remodeling and significant QTc prolongation, regardless concomitant antimicrobial therapy. Although transient, these changes may significantly increase the risk of life-threatening ventricular arrhythmia in these patients. It is timely and warranted to transpose these findings to the current coronavirus disease 2019 (COVID-19) pandemic, in which both increased amounts of circulating cytokines and cardiac arrhythmias are demonstrated along with a frequent concomitant treatment with several QT-prolonging drugs. Graphic Abstract: A graphic abstract is available for this article.

Androgen Deprivation Therapy for Prostatic Cancer in Patients With Torsades de Pointes.

BACKGROUND: Men normally have shorter heart rate-corrected QT interval (QTc) than women, at least in part due to accelerating effects of testosterone on ventricular repolarization. Accumulating data suggest that androgen-deprivation therapy (ADT) used for the treatment of prostatic cancer, may increase Torsades de Pointes (TdP) risk by prolonging QTc. However, the evidence for such an association is currently limited to few case reports, in most cases deriving from the analysis of uncontrolled sources such as pharmacovigilance databases. OBJECTIVE: To better determine the clinical impact of ADT on TdP development, we examined the prevalence of this therapy in a consecutive cohort of 66 TdP patients, prospectively collected over a ~10 years period. METHODS AND RESULTS: We found and described four patients who were under ADT for prostatic cancer when TdP occurred, and in two cases degenerated to cardiac arrest. Notably, in this unselected population, ADTs unexpectedly represented the second most frequently administered QT-prolonging medication in males (4/24, 17%), after amiodarone. Moreover, in the ADT patients, a blood withdrawal was performed within 24 h from TdP/marked QTc prolongation occurrence and circulating concentration of androgens and gonadothropins were measured. As expected, all cases showed markedly reduced testosterone levels (total, free, and available). CONCLUSION: We provide evidence that a significant proportion of patients developing TdP were under treatment with ADT for prostatic cancer, thus confirming the clinical relevance of previous pharmacovigilance signals. An accurate assessment of the arrhythmic risk profile should be included in the standard of care of prostatic cancer patients before starting ADT.

Systemic Inflammation Rapidly Induces Reversible Atrial Electrical Remodeling: The Role of Interleukin-6-Mediated Changes in Connexin Expression.

Background Systemic inflammation is a strong predictor of atrial fibrillation. A key role for electrical remodeling is increasingly recognized, and experimental data suggest that inflammatory cytokines can directly affect connexins resulting in gap-junction dysfunction. We hypothesized that systemic inflammation, regardless of its origin, promotes atrial electric remodeling in vivo, as a result of cytokine-mediated changes in connexin expression. Methods and Results Fifty-four patients with different inflammatory diseases and elevated C-reactive protein were prospectively enrolled, and electrocardiographic P-wave dispersion indices, cytokine levels (interleukin-6, tumor necrosis factor-α, interleukin-1, interleukin-10), and connexin expression (connexin 40, connexin 43) were measured during active disease and after reducing C-reactive protein by >75%. Moreover, peripheral blood mononuclear cells and atrial tissue specimens from an additional sample of 12 patients undergoing cardiac surgery were evaluated for atrial and circulating mRNA levels of connexins. Finally, in vitro effects of interleukin-6 on connexin expression were studied in HL-1 mouse atrial myocytes. In patients with active inflammatory diseases, P-wave dispersion indices were increased but rapidly decreased within days when C-reactive protein normalizes and interleukin-6 levels decline. In inflammatory disease patients, both P-wave dispersion indices and interleukin-6 changes were inversely associated with circulating connexin levels, and a positive correlation between connexin expression in peripheral blood mononuclear cells and atrial tissue was demonstrated. Moreover, interleukin-6 significantly reduced connexin expression in HL-1 cells. Conclusions Our data suggest that regardless of specific etiology and organ localization, systemic inflammation, via interleukin-6 elevation, rapidly induces atrial electrical remodeling by down-regulating cardiac connexins. Although transient, these changes may significantly increase the risk for atrial fibrillation and related complications during active inflammatory processes.

Proton Pump Inhibitors and Serum Magnesium Levels in Patients With Torsades de Pointes.

Background: Torsades de pointes (TdP) is a life-threatening ventricular tachycardia occurring in long QT-syndrome patients. It usually develops when multiple QT-prolonging factors are concomitantly present, more frequently drugs and electrolyte imbalances. Since proton-pump inhibitors (PPIs)-associated hypomagnesemia is an increasingly recognized adverse event, PPIs were recently included in the list of drugs with conditional risk of TdP, despite only few cases of TdP in PPI users have been reported so far. Objectives: Aim of the present study is to evaluate whether PPI-induced hypomagnesemia actually has a significant clinical impact on the risk of TdP in the general population. Methods: Forty-eight unselected patients who experienced TdP were consecutively enrolled (2008-2017). Shortly after the first TdP episode, in those patients who did not receive magnesium sulfate and/or potassium or calcium replacement therapy, serum electrolytes were measured and their relationship with PPI usage analyzed. Results: Many patients (28/48, 58%) were under current PPI treatment when TdP occurred. Among TdP patients in whom serum electrolyte determinations were obtained before replacement therapy (27/48), those taking PPIs had significantly lower serum magnesium levels than those who did not. Hypomagnesemia occurred in ~40% of patients receiving PPIs (6/14), in all cases after an extended treatment (>2 weeks). In patients taking PPIs the mean QT-prolonging risk factor number was significantly higher than in those who did not, a difference which was mainly driven by lower magnesium levels. Conclusions: In unselected TdP patients, PPI-induced hypomagnesemia was common and significantly contributed to their cumulative arrhythmic risk. By providing clinical support to current recommendations, our data confirm that more awareness is needed when a PPI is prescribed, specifically as regards the risk of life-threatening arrhythmias.

Torsades de Pointes in Patients with Polymyalgia Rheumatica.

Polymyalgia rheumatica (PMR) represents the most common inflammatory rheumatic disease of the elderly. It is characterized by synovitis of proximal joints and extra-articular synovial structures, along with chronic high-grade systemic inflammation. PMR is closely related to giant cell arteritis (GCA), a large-vessel vasculitis that involves the major branches of the aorta, particularly the extracranial branches of carotid artery including temporal arteries. It is currently believed that PMR and GCA may represent different manifestations of the same disease process. Chronic systemic inflammation is presently recognized as one of the key pathogenic mechanisms underlying cardiovascular disease and associated complications, including cardiac arrhythmias and sudden death. In this regard, several studies demonstrated that besides promoting structural heart disease, inflammatory activation may also be per se arrhythmogenic, via cytokine-mediated effects on cardiac electrophysiology. In particular, increasing evidence points to inflammation as a novel risk factor for QTc prolongation and related life-threatening arrhythmias, specifically Torsade de Pointes (TdP). Starting from the report of two cases of TdP occurring in PMR patients with active disease and elevated circulating IL-6 levels, we here reviewed literature data regarding heart involvement and arrhythmic events in PMR/GCA, as well as TdP risk in inflammatory diseases. Potential underlying mechanisms were dissected, by focusing on the driving role of inflammatory activation.

Systemic inflammation as a novel QT-prolonging risk factor in patients with torsades de pointes.

OBJECTIVE: Increasing evidence indicates systemic inflammation as a new potential cause of acquired long QT syndrome (LQTS), via cytokine-mediated changes in cardiomyocyte ion channels. Torsade de pointes (TdP) is a life-threatening polymorphic ventricular tachycardia occurring in patients with LQTS, usually when multiple QT-prolonging factors are simultaneously present. Since classical risk factors cannot fully explain TdP events in a number of patients, we hypothesised that systemic inflammation may represent a currently overlooked risk factor contributing to TdP development in the general population. METHODS: Forty consecutive patients who experienced TdP (TdP cohort) were consecutively enrolled and circulating levels of C-reactive protein (CRP) and proinflammatory cytokines (interleukin-6 (IL-6), tumour necrosis factor alpha (TNFα), interleukin-1 (IL-1)) were compared with patients with active rheumatoid arthritis (RA), comorbidity or healthy controls. An additional 46 patients with different inflammatory conditions (acute infections, n=31; immune-mediated diseases, n=12; others, n=3) and elevated CRP (inflammatory cohort) were prospectively enrolled, and corrected QT (QTc) and cytokine levels were measured during active disease and after a CRP decrease of >75% subsequent to therapy. RESULTS: In the TdP cohort, 80% of patients showed elevated CRP levels (median: ~3 mg/dL), with a definite inflammatory disease identifiable in 18/40 cases (acute infections, n=12; immune-mediated diseases, n=5; others, n=1). In these subjects, IL-6, but not TNFα and IL-1, was ~15-20 times higher than in controls, and comparable to RA patients. In the inflammatory cohort, where QTc prolongation was common (mean values: 456.6±30.9 ms), CRP reduction was associated with IL-6 level decrease and significant QTc shortening (-22.3 ms). CONCLUSION: The data are first to show that systemic inflammation via elevated IL-6 levels may represent a novel QT-prolonging risk factor contributing to TdP occurrence in the presence of other classical risk factors. If confirmed, this could open new avenues in antiarrhythmic therapy.

Marked QTc Prolongation and Torsades de pointes in Patients with Chronic Inflammatory Arthritis.

Mounting evidence indicates that in chronic inflammatory arthritis (CIA), QTc prolongation is frequent and correlates with systemic inflammatory activation. Notably, basic studies demonstrated that inflammatory cytokines induce profound changes in potassium and calcium channels resulting in a prolonging effect on cardiomyocyte action potential duration, thus on the QT interval on the electrocardiogram. Moreover, it has been demonstrated that in rheumatoid arthritis (RA) patients, the risk of sudden cardiac death is significantly increased when compared to non-RA subjects. Conversely, to date no data are available about torsades de pointes (TdP) prevalence in CIA, and the few cases reported considered CIA only an incidental concomitant disease, not contributing factor to TdP development. We report three patients with active CIA developing marked QTc prolongation, in two cases complicated with TdP degenerating to cardiac arrest. In these patients, a blood sample was obtained within 24 h from TdP/marked QTc prolongation occurrence, and levels of IL-6, TNFα, and IL-1 were evaluated. In all three cases, IL-6 was markedly elevated, ~10 to 100 times more than reference values. Moreover, one patient also showed high circulating levels of TNFα and IL-1. In conclusion, active CIA may represent a currently overlooked QT-prolonging risk factor, potentially contributing in the presence of other "classical" risk factors to TdP occurrence. In particular, a relevant role may be played by elevated circulating IL-6 levels via direct electrophysiological effects on the heart. This fact should be carefully kept in mind, particularly when recognizable risk factors are already present and/or the addition of QT-prolonging drugs is required.

Arrhythmogenicity of Anti-Ro/SSA Antibodies in Patients With Torsades de Pointes.

BACKGROUND: In patients with autoimmune disease, anti-Ro/SSA antibodies (anti-Ro/SSA) are responsible for a novel autoimmune-associated long-QT syndrome by targeting the hERG potassium channel and inhibiting the related current (IKr). Because anti-Ro/SSA are also present in a significant proportion of healthy subjects and may be associated with torsades de pointes (TdP) arrhythmia, we tested the hypothesis that anti-Ro/SSA may represent a silent risk factor in patients developing TdP. METHODS AND RESULTS: Twenty-five consecutive patients who experienced TdP were prospectively collected independent of ongoing therapies and concomitant diseases. Anti-Ro/SSA were detected by fluoroenzyme immunoassay, immuno-Western blotting, and line-blot immunoassay. Purified IgGs from anti-Ro/SSA-positive and anti-Ro/SSA-negative patients were tested on IKr using HEK293 cells stably expressing the hERG channel. As expected, in TdP patients, many known corrected QT interval-prolonging risk factors were simultaneously present, including hypokalemia that was the most common (52%). Anti-Ro/SSA were present in 60% of the subjects, mostly the anti-Ro/SSA-52-kD subtype detected by immuno-Western blotting only. A history of autoimmune disease was found in only 2 of anti-Ro/SSA-positive patients. Experimental data demonstrated that purified anti-Ro/SSA-positive IgGs significantly inhibited IKr and cross reacted with hERG-channel proteins. Moreover, anti-Ro/SSA-positive sera exhibited high reactivity with a peptide corresponding to the hERG-channel pore-forming region. CONCLUSIONS: Anti-Ro/SSA may represent a clinically silent novel risk factor for TdP development via an autoimmune-mediated electrophysiological interference with the hERG channel. We propose that TdP patients may benefit from specific anti-Ro/SSA testing even in the absence of autoimmune diseases as immunomodulating therapies may be effective in shortening corrected QT interval and reducing TdP recurrence risk.

Weather-related changes in 24-hour blood pressure profile: effects of age and implications for hypertension management.

A downward titration of antihypertensive drug regimens in summertime is often performed on the basis of seasonal variations of clinic blood pressure (BP). However, little is known about the actual interaction between outdoor air temperature and the effects of antihypertensive treatment on ambulatory BP. The combined effects of aging, treatment, and daily mean temperature on clinic and ambulatory BP were investigated in 6404 subjects referred to our units between October 1999 and December 2003. Office and mean 24-hour systolic BP, as well as morning pressure surge, were significantly lower in hot (>90th percentiles of air temperature; 136+/-19, 130+/-14, and 33.3+/-16.1 mm Hg; P<0.05 for all), and higher in cold (<10th percentiles) days (141+/-12, 133+/-11, and 37.3+/-9.5 mm Hg; at least P<0.05 for all) when compared with intermediate days (138+/-18, 132+/-14, and 35.3+/-15.4 mm Hg). At regression analysis, 24-hour and daytime systolic pressure were inversely related to temperature (P<0.01 for all). Conversely, nighttime systolic pressure was positively related to temperature (P<0.02), with hot days being associated with higher nighttime pressure. Air temperature was identified as an independent predictor of nighttime systolic pressure increase in the group of elderly treated hypertensive subjects only. No significant relationship was found between air temperature and heart rate. Our results show for the first time that hot weather is associated with an increase in systolic pressure at night in treated elderly hypertensive subjects. This may be because of a nocturnal BP escape from the effects of a lighter summertime drug regimen and may have important implications for seasonal modulation of antihypertensive treatment.

Hyperglycemia activates JAK2 signaling pathway in human failing myocytes via angiotensin II-mediated oxidative stress.

Hyperglycemia was reported to enhance angiotensin (Ang) II generation in rat cardiomyocytes, and Ang II inhibition reduces cardiovascular morbidity and mortality in diabetic patients. In diabetic patients, the enhanced activation of intracellular pathways related with myocyte hypertrophy and gene expression might enhance the progression of cardiac damage. Therefore, we investigated the effects of glucose on Ang II-mediated activation of Janus-activated kinase (JAK)-2, a tyrosine kinase related with myocyte hypertrophy and cytokine and fibrogenetic growth factor overexpression, in ventricular myocytes isolated from nonfailing human hearts (n = 5) and failing human hearts (n = 8). In nonfailing myocytes, JAK2 phosphorylation was enhanced by Ang II only in the presence of high glucose (25 mmol/l) via Ang II type I (AT1) receptors (+79% vs. normal glucose, P < 0.05). JAK2 activation was prevented by inhibitors of reactive oxygen species (ROS) generation (diphenyleneiodonium [DPI], tiron, and apocynin). In myocytes isolated from failing hearts, JAK2 phosphorylation was enhanced by high glucose alone (+107%, P < 0.05). High glucose-induced JAK2 activation was blunted by both ACE inhibition (100 nmol/l ramipril) and AT1 antagonism (1 mumol/l valsartan), thus revealing that the effects are mediated by autocrine Ang II production. Inhibition of ROS generation also prevented high glucose-induced JAK2 phosphorylation. In conclusion, in human nonfailing myocytes, high glucose allows Ang II to activate JAK2 signaling, whereas in failing myocytes, hyperglycemia alone is able to induce Ang II generation, which in turn activates JAK2 via enhanced oxidative stress.

Pulmonary injury follows systemic inflammatory reaction in infrarenal aortic surgery.

OBJECTIVE: To investigate whether an inflammatory response occurs in patients undergoing infrarenal aortic abdominal aneurysm repair, the localization and timing (ischemia and/or reperfusion) of this activation, and finally whether it affects postoperative pulmonary function. DESIGN: Prospective, observational study. SETTING: Academic referral center in Italy. PATIENTS: We included 12 patients undergoing infrarenal aortic abdominal aneurysm repair and 12 patients undergoing major abdominal surgery. INTERVENTIONS: Timed measurement of gene activation (angiotensinogen, angiotensin type 1 receptor, angiotensin-converting enzyme, and interleukin-6 genes) in muscle biopsies by reverse transcriptase-polymerase chain reaction (RT-PCR), and prospective assessment of interleukin-6 plasma concentration and pulmonary function (Pao2/FIO2 and Pao2/PAO2 ratios). MEASUREMENTS AND MAIN RESULTS: After 30 mins of aortic clamping, angiotensinogen, angiotensin type 1 receptor, angiotensin-converting enzyme, and interleukin-6 genes were all overexpressed at RT-PCR studies in quadriceps muscle of patients undergoing aortic abdominal aneurysm repair, and the overexpression persisted after reperfusion. In situ hybridization and immunohistochemistry revealed that the inflammatory response was localized in endothelial cells. A significant increase in plasma interleukin-6 concentrations was then detectable at 6 and 12 hrs after reperfusion in aortic abdominal aneurysm surgery compared with patients undergoing abdominal surgery (p < .05). The increase in interleukin-6 plasma concentration was then followed (12 and 24 hrs after surgery) by a significant reduction of Pao2/ FIO2 and Pao2/PAO2 ratios (p < .05 vs. abdominal surgery). CONCLUSIONS: The present study shows that a) during aortic surgery, the genes for interleukin-6 and for the components of the local renin-angiotensin system (angiotensinogen, angiotensin-converting enzyme, and angiotensin type 1 receptor subtype) are activated early in the ischemic muscle, and activation persists during reperfusion; b) interleukin-6 plasma concentration increases only in patients with tissue ischemia (aortic abdominal aneurysm), whereas no changes are detectable in patients with abdominal surgery; and finally c) the occurrence of systemic inflammatory reaction with increased interleukin-6 plasma concentrations is followed by impaired pulmonary function.