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The role of hyperhomocysteinemia in coronary artery disease (CAD) patients remains unclear. The present study evaluated the relationship between homocysteine (HCys), adenosine plasma concentration (APC), plasma uric acid, and CAD severity evaluated using the SYNTAX score. We also evaluated in vitro the influence of adenosine on HCys production by hepatoma cultured cells (HuH7). Seventy-eight patients (mean age ± SD: 66.3 [+ or -] 11.3; mean SYNTAX score: 19.9 ± 12.3) and 30 healthy subjects (mean age: 61 ± 13) were included. We incubated HuH7 cells with increasing concentrations of adenosine and addressed the effect on HCys level in cell culture supernatant. Patients vs. controls had higher APC (0.82 [+ or -] 0.5 µmol/L vs 0.53 ± 0.14 µmol/L; p < 0.01), HCys (15 ± 7.6 µmol/L vs 6.8 ± 3 µmol/L, p < 0.0001), and uric acid (242.6 ± 97 vs 202 ± 59, p < 0.05) levels. APC was correlated with HCys and uric acid concentrations in patients (Pearson's R = 0.65 and 0.52; p < 0.0001, respectively). The SYNTAX score was correlated with HCys concentration. Adenosine induced a time- and dose-dependent increase in HCys in cell culture. Our data suggest that high APC is associated with HCys and uric acid concentrations in CAD patients. Whether the increased APC participates in atherosclerosis or, conversely, is part of a protective regulation process needs further investigations. Key words: adenosine, homocysteine, coronary artery disease. Le role de l'hyperhomocysteinemie dans la coronaropathie n'a toujours pas ete precise. La presente etude vise a evaluer le lien entre les concentrations plasmatiques d'homocysteine (HCys), d'adenosine (CPA), d'acide urique et la gravite de la coronaropathie a l'aide du score SYNTAX. Nous avons aussi evalue in vitro l'influence de l'adenosine sur la production d'HCys par les cellules d'hepatome en culture (HuH7). Nous avons inscrit a l'etude 78 patients (moyenne d'age ± E-T : 66,3 ± 11,3; score SYNTAX moyen: 19,9 ± 12,3) et 30 sujets en bonne sante (moyenne d'age : 61 ± 13). Par ailleurs, nous avons fait incuber des cellules HuH7 en presence d'adenosine a des concentrations croissantes et evalue son effet sur la concentration d'HCys dans le surnageant de culture cellulaire. Les concentrations plasmatiques des elements suivants etaient plus elevees chez les patients que chez les temoins: adenosine (0,82 ± 0,5 µmol/L p/r a 0,53 ± 0,14 µmol/L, p < 0,01), HCys (15 ± 7,6 µmol/L p/r a 6,8 [+ or -] 3 µmol/L, p < 0,0001) et acide urique (242,6 ± 97 p/r a 202 ± 59, p < 0,05). L'augmentation de la CPA etait proportionnelle a celles des concentrations d'HCys et d'acide urique chez les patients (R de Pearson : 0,65 et 0,52, respectivement; p < 0,0001) et l'augmentation du score SYNTAX etait proportionnelle a celle des concentrations d'HCys. En culture cellulaire, nous avons observe une augmentation, dependante du temps et de la dose, des concentrations d'HCys en presence d'adenosine. Nos donnees laissent entendre que la CPA est associee aux concentrations d'HCys et d'acide urique chez les patients presentant une coronaropathie. Par ailleurs, d'autres etudes seraient necessaries pour savoir si la CPA participe a l'atherosclerose ou si, inversement, elle contribue a un processus de protection regulateur. [Traduit par la Redaction] Mots-cles: adenosine, homocysteine, coronaropathie., Introduction Hyperhomocysteinemia is associated with cardiovascular disease (Hoogeveen et al. 2000; Kumakura et al. 2015; McCully 1969; Refsum et al. 1998; Riksen et al. 2003) and a predictor for death [...]

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High blood levels of low-density lipoprotein (LDL)-cholesterol (LDL-C) are associated with atherosclerosis, mainly by promoting foam cell accumulation in vessels. As cholesterol is an essential component of cell plasma membranes and a regulator of several signaling pathways, LDL-C excess may have wider cardiovascular toxicity. We examined, in untreated hypercholesterolemia (HC) patients, selected regardless of the cause of LDL-C accumulation, and in healthy participants (HP), the expression of the adenosine A 2A receptor (A 2A R), an anti-inflammatory and vasodilatory protein with cholesterol-dependent modulation, and Flotillin-1, protein marker of cholesterol-enriched plasma membrane domains. Blood cardiovascular risk and inflammatory biomarkers were measured. A 2A R and Flotillin-1 expression in peripheral blood mononuclear cells (PBMC) was lower in patients compared to HP and negatively correlated to LDL-C blood levels. No other differences were observed between the two groups apart from transferrin and ferritin concentrations. A 2A R and Flotillin-1 proteins levels were positively correlated in the whole study population. Incubation of HP PBMCs with LDL-C caused a similar reduction in A 2A R and Flotillin-1 expression. We suggest that LDL-C affects A 2A R expression by impacting cholesterol-enriched membrane microdomains. Our results provide new insights into the molecular mechanisms underlying cholesterol toxicity, and may have important clinical implication for assessment and treatment of cardiovascular risk in HC.

Although very common, the precise mechanisms that explain the symptomatology of neuroendocrine syncope (NES) remain poorly understood. This disease, which can be very incapacitating, manifests itself as a drop in blood pressure secondary to vasodilation and/or extreme slowing of heart rate. As studies continue, the involvement of the adenosinergic system is becoming increasingly evident. Adenosine, which is an ATP derivative, may be involved in a large number of cases. Adenosine acts on G protein-coupled receptors with seven transmembrane domains. A 1 and A 2A adenosine receptor dysfunction seem to be particularly implicated since the activation leads to severe bradycardia or vasodilation, respectively, two cardinal symptoms of NES. This mini-review aims to shed light on the links between dysfunction of the adenosinergic system and NHS. In particular, signal transduction pathways through the modulation of cAMP production and ion channels in relation to effects on the cardiovascular system are addressed. A better understanding of these mechanisms could guide the pharmacological development of new therapeutic approaches.

Background & Aims: Nutritional predisposition to severe coronavirus disease 2019 (COVID-19) remains unclear. Zinc deficiency could be critical since it is associated with a higher susceptibility to infections. We evaluated the prevalence of hypozincemia in the early stage of COVID-19, its association with risk factors for severe COVID-19 and its prognostic value for hospitalization for respiratory complications within 10 days., Methods: For 152 COVID-19 patients and 88 non-COVID-19 patients admitted to COVID-19 screening centers, national early warning score for COVID-19 (NEWS) and laboratory analyses were performed to identify the risk for severe COVID-19. Multivariable logistic regression analysis assessed whether hypozincemia was an independent predictor of hospitalization for respiratory complications within 10 days (primary judgment criterion). The secondary judgment criteria were high NEWS score (≥7), comorbidities and biomarkers associated with severe COVID-19., Results: Hypozincemia was more frequent in COVID-19 patients compared to non-COVID-19 patients (27.6% vs 11.4%; p = 0.003). Older patients (≥65 years) and medically assisted nursing home residents were at higher risk of hypozincemia (p < 0.01). Hypozincemia was associated with a worse NEWS score (p < 0.01) and lymphopenia (p < 0.001). Hypozincemia was independently associated with hospitalization for respiratory complications within 10 days (OR = 10.9, 95% CI = 2.3-51.6, p = 0.002)., Conclusions: In the early stage of COVID-19, the prevalence of hypozincemia exceeded 20%. Hypozincemia was an independent predictor of hospitalization for respiratory complications within 10 days. This may suggest the importance of early detection and treatment of zinc deficiency in the nutritional management of COVID-19, especially in older people. Therefore, intervention and adjuvant treatment trials are strongly needed., Competing Interests: Conflict of interest The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Atrial fibrillation (AF) is the most common arrhythmia in the world. Because the key to developing innovative therapies that limit the onset and the progression of AF is to fully understand the underlying molecular mechanisms of AF, the aim of the present narrative review is to report the most recent advances in the potential role of the adenosinergic system in the pathophysiology of AF. After a comprehensive approach describing adenosinergic system signaling and the mechanisms of the initiation and maintenance of AF, we address the interactions of the adenosinergic system's signaling with AF. Indeed, adenosine release can activate four G-coupled membrane receptors, named A 1 , A 2A , A 2B and A 3 . Activation of the A 2A receptors can promote the occurrence of delayed depolarization, while activation of the A 1 receptors can shorten the action potential's duration and induce the resting membrane's potential hyperpolarization, which promote pulmonary vein firing, stabilize the AF rotors and allow for functional reentry. Moreover, the A 2B receptors have been associated with atrial fibrosis homeostasis. Finally, the adenosinergic system can modulate the autonomous nervous system and is associated with AF risk factors. A question remains regarding adenosine release and the adenosine receptors' activation and whether this would be a cause or consequence of AF.

Fibromuscular dysplasia (FMD) is a non-inflammatory vascular disease that is characterized by unexplained systemic hypertension occurring in young people, associated with arterial stenosis, aneurysm rupture, intracranial/renal infarction, and stroke. Although the gold standard for the diagnosis remains catheter-angiography, biological markers would be helpful due to the delay from first symptom to diagnosis. Adenosine is an ATP derivative, that may be implicated in FMD pathophysiology. We hypothesized that changes in adenosine blood level (ABL) and production of adenosine receptors may be associated with FMD. Using peripheral blood mononuclear cells, we evaluated A1, A2A, and A2B receptor production by Western blot, in 67 patients (17 men and 50 women, mean (range) age 55 (29−77) years and 40 controls, 10 men and 30 women, mean (range) age 56 (37−70)). ABL was evaluated by liquid chromatography, mass spectrometry. ABL was significantly higher in patients vs. controls, mean (range): 1.7 (0.7−3) µmol/L vs. controls 0.6 (0.4−0.8) µmol/L (+180%) p < 0.001. While A1R and A2AR production did not differ in patients and controls, we found an over-production of A2BR in patients: 1.70 (0.90−2.40; arbitrary units) vs. controls = 1.03 (0.70−1.40), mean + 65% (p < 0.001). A2BR production with a cut off of 1.3 arbitrary units, gives a good sensitivity and specificity for the diagnosis. Production measurement of A2BR on monocytes and ABL could help in the diagnosis, especially in atypical or with poor symptoms.

Climbers and aviators are exposed to severe hypoxia at high altitudes, whereas divers are exposed to hyperoxia at depth. The aim of this study was to report changes in the adenosinergic system induced by exposure to extreme oxygen partial pressures. At high altitudes, the increased adenosine concentration contributes to brain protection against hypoxia through various mechanisms such as stimulation of glycogenolysis for ATP production, reduction in neuronal energy requirements, enhancement in 2,3-bisphosphoglycerate production, and increase in cerebral blood flow secondary to vasodilation of cerebral arteries. In the context of mountain illness, the increased level of A 2A R expression leads to glial dysfunction through neuroinflammation and is involved in the pathogenesis of neurological disorders. Nonetheless, a high level of adenosine concentration can protect against high-altitude pulmonary edema via a decrease in pulmonary arterial pressure. The adenosinergic system is also involved in the acclimatization phenomenon induced by prolonged exposure to altitude hypoxia. During hyperoxic exposure, decreased extracellular adenosine and low A 2A receptor expression contribute to vasoconstriction. The resulting decrease in cerebral blood flow is considered a preventive phenomenon against cerebral oxygen toxicity through the decrease in oxygen delivery to the brain. With regard to lung oxygen toxicity, hyperoxia leads to an increase in extracellular adenosine, which acts to preserve pulmonary barrier function. Changes in the adenosinergic system induced by exposure to extreme oxygen partial pressures frequently have a benefit in decreasing the risk of adverse effects.

The evaluation of suspected coronary artery disease (CAD) in the medical community is challenging. Patients with suspected coronary chronic syndrome (CCS) are referred by the medical community to be assessed by specialists for the performance of noninvasive tests that have high rates of false positives and false negatives. While troponins are the gold standard for evaluate myocardial injuries, there is no biomarker to assess myocardial ischemia in patient populations with negative electrocardiography or without an increase in troponin level. A2A adenosine receptors control the coronary blood flow through its vasodilating properties. It has been shown that patients with CAD have a lower A2AR expression on peripheral blood mononuclear cells, suggesting a link between A2AR production and the severity of CAD. Herein, we present a new and innovative method of inhibition ELISA for A2AR in the plasma of patients who permit the evaluation of the amount of soluble A2AR. For this analysis, the total study sample was 54, including 31 patients with CAD with stenosis > 50% and a significant fractional flow reserve (FFR < 0.8) (Group 1) and 23 patients with normal or non-obstructive coronary arteries (stenosis < 50% and nonsignificant FFR > 0.8) (Group 2). The % inhibition (which is linked to the presence of soluble receptors) with the plasma of patients with FFR < 0.8 was significantly lower than that of patients with FFR > 0.8 (median [range]: 68% [20.7−86.9] vs. 83% [67−88.4]; p < 0.001). The ROC curve indicated a good sensitivity/specificity ratio with a cut off of 72.5% and an area under the curve of 0.87. In conclusion, a rapid ELISA to assess soluble A2AR in the plasma shows promise to screen patients suspected of having CAD.

Background: Aspiration pneumonia is the most common respiratory complication following out-of-hospital cardiac arrests (OHCA). Alpha-amylase (α-amylase) in pulmonary secretions is a biomarker of interest in detecting inhalation. The main goal of this study is to evaluate the performance of bronchoalveolar levels of α-amylase in early diagnosis of aspiration pneumonia, in patients admitted to intensive care unit (ICU) after OHCA., Methods: This is a prospective single-center trial, led during 5 years (July 2015 to September 2020). We included patients admitted to ICU after OHCA. A protected specimen bronchial brushing and a mini-bronchoalveolar lavage (mini-BAL) were collected during the first 6 h after admission. Dosage of bronchial α-amylase and standard bacterial analysis were performed. Investigators confirmed pneumonia diagnosis using clinical, radiological, and microbiological criteria. Every patient underwent targeted temperature management., Results: 88 patients were included. The 34% (30 patients) developed aspiration pneumonia within 5 days following admission. The 55% (17) of pneumonias occurred during the first 48 h. The 57% of the patients received a prophylactic antibiotic treatment on their admission day. ICU mortality was 50%. Median value of bronchial α-amylase did not differ whether patients had aspiration pneumonia (15 [0-94]) or not (3 [0-61], p = 0,157). Values were significantly different concerning early-onset pneumonia (within 48 h) [19 (7-297) vs. 3 (0-82), p = 0,047]. If one or more microorganisms were detected in the initial mini-BAL, median value of α-amylase was significantly higher [25 (2-230)] than in sterile cultures (2 [0-43], p = 0,007). With an 8.5 IU/L cut-point, sensitivity and specificity of α-amylase value for predicting aspiration pneumonia during the first 2 days were respectively 74 and 62%. True positive and negative rates were respectively 44 and 86%. The area under the ROC curve was 0,654 (CI 95%; 0,524-0,785). Mechanical ventilation duration, length of ICU stay, and mortality were similar in both groups., Conclusion: In our study, dosage of bronchial α-amylase was not useful in predicting aspiration pneumonia within the first 5 days after ICU admission for OHCA. Performance in predicting early-onset pneumonia was moderate., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Moussali, Cauchois, Carvelli, Hraeich, Bouzana, Lesaux, Boucekine, Bichon, Gainnier, Fromonot and Bourenne.)

Adenosine is a ubiquitous nucleoside that is implicated in the occurrence of clinical manifestations of neuro-humoral syncope (NHS). NHS is characterized by a drop in blood pressure due to vasodepression together with cardio inhibition. These manifestations are often preceded by prodromes such as headaches, abdominal pain, feeling of discomfort or sweating. There is evidence that adenosine is implicated in NHS. Adenosine acts via four subtypes of receptors, named A 1 (A 1 R), A 2 A (A 2A R), A 2B (A 2B R) and A 3 (A 3 R) receptors, with all subtypes belonging to G protein membrane receptors. The main effects of adenosine on the cardiovascular system occurs via the modulation of potassium ion channels (IK Ado , K ATP ), voltage-gate calcium channels and via cAMP production inhibition (A 1 R and A 3 R) or, conversely, through the increased production of cAMP (A 2A/B R) in target cells. However, it turns out that adenosine, via the activation of A 1 R, leads to bradycardia, sinus arrest or atrioventricular block, while the activation of A 2A R leads to vasodilation; these same manifestations are found during episodes of syncope. The use of adenosine receptor antagonists, such as theophylline or caffeine, should be useful in the treatment of some forms of NHS. The aim of this review was to summarize the main data regarding the link between the adenosinergic system and NHS and the possible consequences on NHS treatment by means of adenosine receptor antagonists.

Objectives: Polyuria-polydipsia syndrome (PPS) is a common presentation in children but the differential diagnosis rests on burdensome water deprivation tests. The aims of this study were to determine a copeptin threshold to distinguish patients with central diabetes insipidus from those with primary polydipsia and to estimate the normal range of copeptin concentrations in children., Design: Single-centre retrospective descriptive study., Patients: Two hundred and seventy-eight children aged 2 months to 18 years who consulted for PPS (N = 40) or other reasons (control group, N = 238) at La Timone University Hospital in Marseille, France, between April 2015 and September 2019 and had a copeptin assay., Measurements: Ultrasensitive copeptin assays on blood samples., Results: Among the children with PPS, the mean copeptin concentrations were 1.72, 55.2 and 15.7 pmol/l in those with central diabetes insipidus (N = 21), nephrogenic diabetes insipidus (N = 3), and primary polydipsia (N = 16), respectively. Copeptin levels lower than 3.53 pmol/l were diagnostic of central diabetes insipidus with 100% sensitivity and 87.4% specificity (p < .001). The 5th-95th copeptin percentile range in the control group was 2.53-21.03 pmol/L. Copeptin levels were significantly higher in boys than in girls but there was no association with age, pubertal stage, body mass index, or the reason for consulting., Conclusions: Our results indicate copeptin assays may be valuable in the differential diagnosis of PPS in children. Larger prospective studies are required to establish their accuracy in everyday clinical practice., (© 2021 John Wiley & Sons Ltd.)

Objective: Although atrial fibrillation is a common cardiac arrhythmia in humans, the mechanism that leads to the onset of this condition is poorly elucidated. Adenosine is suspected to be implicated in the trigger of atrial fibrillation (AF) through the activation of its membrane receptors, mainly adenosine receptor (AR) subtypes A 1 R and A 2 R. In this study, we compared blood adenosine concentration (BAC), and A 1 R, A 2A R, and A 2B R production in right (RA) and left atrium (LA), and on peripheral blood mononuclear cells (PBMCs) in patients with underlying structural heart disease undergoing cardiac surgery with or without peri-operative AF (PeOpAF). Methods: The study group consisted of 39 patients (30 men and 9 women, mean age, range 65 [40-82] years) undergoing cardiac surgery and 20 healthy patients (8 women and 12 men; mean age, range 60 [39-72] years) as controls were included. Among patients, 15 exhibited PeOpAF. Results: Blood adenosine concentration was higher in patients with PeOpAF than others. A 2A R and A 2B R production was higher in PBMCs of patients compared with controls and was higher in PeOpAF patients than other patients. In LA and RA, the production of A 2A R and A 2B R was higher in patients with PeOpAF than in other patients. Both A 2A R and A 2B R production were higher in LA vs. RA. A 1 R production was unchanged in all situations. Finally, we observed a correlation between A 1 R, A 2A R, and A 2B R production evaluated on PBMCs and those evaluated in LA and RA. Conclusions: Perioperative AF was associated with high BAC and high A 2A R and A 2B R expression, especially in the LA, after cardiac surgery in patients with underlying structural heart disease. Whether these increases the favor in triggering the AF in this patient population needs further investigation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Maille, Fromonot, Guiol, Marlinge, Baptiste, Lim, Colombani, Chaptal, Chefrour, Gastaldi, Franceschi, Deharo, Gariboldi, Ruf, Mottola and Guieu.)

Background: Many arguments suggest that neutrophils could play a prominent role in COVID-19. However, the role of key components of neutrophil innate immunity in severe forms of COVID-19 has deserved insufficient attention. We aimed to evaluate the involvement of neutrophil elastase, histone-DNA, and DNases in systemic and multi-organ manifestations of COVID-19., Methods: We performed a multicenter study of markers of neutrophil innate immunity in 155 cases consecutively recruited in a screening center, local hospitals, and two regional university hospitals. The cases were evaluated according to clinical and biological markers of severity and multi-organ manifestations and compared to 35 healthy controls., Results: Blood neutrophil elastase, histone-DNA, myeloperoxidase-DNA, and free dsDNA were dramatically increased, and DNase activity was decreased by 10-fold, compared with controls. Neutrophil elastase and histone-DNA were associated with intensive care admission, body temperature, lung damage, and markers of cardiovascular outcomes, renal failure, and increased interleukin-6 (IL-6), IL-8, and CXCR2. Neutrophil elastase was an independent predictor of the computed tomography score of COVID-19 lung damage and the number of affected organs, in multivariate analyses. The increased blood concentrations of NE and neutrophil extracellular traps were related to exacerbation of neutrophil stimulation through IL-8 and CXCR2 increased concentrations and increased serum DAMPs, and to impaired degradation of NETs as a consequence of the dramatic decrease in blood DNase activity., Conclusion: Our results point out the key role of neutrophil innate immunity exacerbation in COVID-19. Neutrophil elastase and DNase could be potential biomarkers and therapeutic targets of severe systemic manifestations of COVID-19., (© 2021 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: The COVID-19 crisis has strained world health care systems. This study aimed to develop an innovative prediction score using clinical and biological parameters (PREDICT score) to anticipate the need of intensive care of COVID-19 patients already hospitalized in standard medical units., Methods: PREDICT score was based on a training cohort and a validation cohort retrospectively recruited in 2020 in the Marseille University Hospital. Multivariate analyses were performed, including clinical, and biological parameters, comparing a baseline group composed of COVID-19 patients exclusively treated in standard medical units to COVID-19 patients that needed intensive care during their hospitalization., Results: Independent variables included in the PREDICT score were: age, Body Mass Index, Respiratory Rate, oxygen saturation, C-reactive protein, neutrophil-lymphocyte ratio and lactate dehydrogenase. The PREDICT score was able to correctly identify more than 83% of patients that needed intensive care after at least 1 day of standard medical hospitalization., Conclusions: The PREDICT score is a powerful tool for anticipating the intensive care need for COVID-19 patients already hospitalized in a standard medical unit. It shows limitations for patients who immediately need intensive care, but it draws attention to patients who have an important risk of needing intensive care after at least one day of hospitalization.

The influence of hyperhomocysteinemia (HHCy) on cardiovascular disease (CVD) remains unclear. HHCy is associated with inflammation and atherosclerosis, and it is an independent risk factor for CVD, stroke and myocardial infarction. However, homocysteine (HCy)-lowering therapy does not affect the inflammatory state of CVD patients, and it has little influence on cardiovascular risk. The HCy degradation product hydrogen sulfide (H 2 S) is a cardioprotector. Previous research proposed a positive role of H 2 S in the cardiovascular system, and we discuss some recent data suggesting that HHCy worsens CVD by increasing the production of H 2 S, which decreases the expression of adenosine A 2A receptors on the surface of immune and cardiovascular cells to cause inflammation and ischemia, respectively.

Hyperhomocysteinemia is associated with coronary artery disease (CAD). The mechanistic aspects of this relationship are unclear. In CAD patients, homocysteine (HCy) concentration correlates with plasma level of adenosine that controls the coronary circulation via the activation of adenosine A 2A receptors (A 2A R). We addressed in CAD patients the relationship between HCy and A 2A R production, and in cellulo the effect of HCy on A 2A R function. 46 patients with CAD and 20 control healthy subjects were included. We evaluated A 2A R production by peripheral blood mononuclear cells using Western blotting. We studied in cellulo (CEM human T cells) the effect of HCy on A 2A R production as well as on basal and stimulated cAMP production following A 2A R activation by an agonist-like monoclonal antibody. HCy concentration was higher in CAD patients vs controls (median, range: 16.6 [7-45] vs 8 [5-12] µM, P < 0.001). A 2A R production was lower in patients vs controls (1.1[0.62-1.6] vs 1.53[0.7-1.9] arbitrary units, P < 0.001). We observed a negative correlation between HCy concentration and A 2A R production (r = -0.43; P < 0.0001), with decreased A 2A R production above 25 µM HCy. In cellulo, HCy inhibited A 2A R production, as well as basal and stimulated cAMP production. In conclusion, HCy is negatively associated with A 2A R production in CAD patients, as well as with A 2A R and cAMP production in cellulo. The decrease in A 2A R production and function, which is known to hamper coronary blood flow and promote inflammation, may support CAD pathogenesis., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Immersion pulmonary edema (IPE) is a serious complication of water immersion during scuba diving. Myocardial ischemia can occur during IPE that worsens outcome. Because myocardial injury impacts the therapeutic management, we aim to evaluate the profile of cardiac markers (creatine phosphokinase (CPK), brain natriuretic peptide (BNP), highly sensitive troponin T (TnT-hs) and ultrasensitive troponin I (TnI-us) of divers with IPE. Twelve male scuba divers admitted for suspected IPE were included. The collection of blood samples was performed at hospital entrance (T0) and 6 h later (T0 + 6 h). Diagnosis was confirmed by echocardiography or computed-tomography scan. Mean ± S.D. BNP (pg/ml) was 348 ± 324 at T0 and 223 ± 177 at T0 + 6 h ( P <0.01), while mean CPK (international units (IUs)), and mean TnT-hs (pg/ml) increased in the same times 238 ± 200 compared with 545 ± 39, ( P =0.008) and 128 ± 42 compared with 269 ± 210, ( P =0.01), respectively; no significant change was observed concerning TnI-us (pg/ml): 110 ± 34 compared with 330 ± 77, P =0.12. At T0 + 6 h, three patients had high TnI-us, while six patients had high TnT-hs. Mean CPK was correlated with TnT-hs but not with TnI-us. Coronary angiographies were normal. The increase in TnT during IPE may be secondary to the release of troponin from non-cardiac origin. The measurement of TnI in place of TnT permits in some cases to avoid additional examinations, especially unnecessary invasive investigations., (© 2018 The Author(s).)

Individuals born after intrauterine growth restriction (IUGR) are at increased risk of developing cardiovascular diseases in adulthood, notably hypertension (HTN). Alterations in the vascular system, particularly impaired endothelium-dependent vasodilation, may play an important role in long-term effects of IUGR. Whether such vascular dysfunction precedes HTN has not been fully established in individuals born after IUGR. Moreover, the intimate mechanisms of altered endothelium-dependent vasodilation remain incompletely elucidated. We therefore investigated, using a rat model of IUGR, whether impaired endothelium-dependent relaxation precedes the development of HTN and whether key components of the l-arginine-nitric oxide (NO) pathway are involved in its pathogenesis. Pregnant rats were fed with a control (CTRL, 23% casein) or low-protein diet (LPD, 9% casein) to induce IUGR. Systolic blood pressure (SBP) was measured by tail-cuff plethysmography in 5- and 8-wk-old male offspring. Aortic rings were isolated to investigate relaxation to acetylcholine, NO production, endothelial NO synthase (eNOS) protein content, arginase activity, and superoxide anion production. SBP was not different at 5 wk but significantly increased in 8-wk-old offspring of maternal LPD (LP) versus CTRL offspring. In 5-wk-old LP versus CTRL males, endothelium-dependent vasorelaxation was significantly impaired but restored by preincubation with l-arginine or the arginase inhibitor S-(2-boronoethyl)-l-cysteine; NO production was significantly reduced but restored by l-arginine pretreatment; total eNOS protein, dimer-to-monomer ratio, and arginase activity were significantly increased; superoxide anion production was significantly enhanced but normalized by pretreatment with the NO synthase inhibitor N ω -nitro-l-arginine. In this model, IUGR leads to early-impaired endothelium-dependent vasorelaxation, resulting from arginase upregulation and eNOS uncoupling, which precedes the development of HTN.

The role of serum uric acid in coronary artery disease has been extensively investigated. It was suggested that serum uric acid level (SUA) is an independent predictor of endothelial dysfunction and related to coronary artery lesions. However, the relationship between SUA and severity of coronary atherosclerosis evaluated via endothelial dysfunction using peripheral arterial tone (PAT) and the reactive hyperhemia index (RHI) has not been investigated during a first episode of acute coronary syndrome (ACS). The aim of our study was to address this point. We prospectively enrolled 80 patients with a first episode of ACS in a single-center observational study. All patients underwent coronary angiography, evaluation of endothelial function via the RHI, and SUA measurement. The severity of the coronary artery lesion was assessed angiographically, and patients were classified in three groups based on the extent of disease and Gensini and SYNTAX scores. Endothelial function was considered abnormal if RHI < 1.67. We identified a linear correlation between SUA and RHI (R 2  = 0.66 P < 0.001). In multivariable analyses, SUA remained associated with RHI, even after adjustment for traditional cardiovascular risk factors and renal function. SUA was associated with severity of coronary artery disease. SUA is associated with severity of coronary atherosclerosis in patients with asymptomatic hyperuricemia. This inexpensive, readily measured biological parameter may be useful to monitor ACS patients.

During exercise, cardiac oxygen-consumption increases and the resulting low oxygen level in myocardium triggers coronary vasodilation. This response to hypoxia is controlled notably by the vasodilator adenosine and its A 2A receptor (A 2A R). According to the "spare receptor" pharmacological model, a strong A 2A R-mediated response can occur in the context of a large number of receptors remaining unoccupied, activation of only a weak fraction of A 2A R (evaluated using K D ) resulting in maximal cAMP production (evaluated using EC 50 ), and hence in maximal coronary vasodilation. In coronary artery disease (CAD), myocardial ischemia limits adaptation to exercise, which is commonly detected using the exercise stress test (EST). We hypothesized that spare A 2A R are present in CAD patients to correct ischemia. Seventeen patients with angiographically-documented CAD and 17 control subjects were studied. We addressed adenosine-plasma concentration and A 2A R-expression at the mononuclear cell-surface, which reflects cardiovascular expression. The presence of spare A 2A R was tested using an innovative pharmacological approach based on a homemade monoclonal antibody with agonist properties. EST was positive in 82% of patients, and in none of the controls. Adenosine plasma-concentration increased by 60% at peak exercise in patients only (p<0.01). Most patients (65%), and none of the controls, had spare A 2A R (identified when EC 50 /K D ≤0.1) and a low A 2A R-expression (mean: -37% vs controls; p<0.01). All patients with spare A 2A R had a positive EST whereas the subjects without spare A 2A R had a negative EST (p<0.05). Spare A 2A R are therefore associated with positive EST in CAD patients and their detection may be used as a diagnostic marker.

High homocysteine (HCy) levels are associated with lymphocyte-mediated inflammatory responses that are sometimes in turn related to hypoxia. Because adenosine is a potent lymphocyte suppressor produced in hypoxic conditions and shares metabolic pathways with HCy, we addressed the influence of high HCy levels on the hypoxia-induced, adenosine-mediated, alteration of lymphocyte viability. We treated mitogen-stimulated human lymphocytes isolated from healthy individuals and the human lymphoma T-cell line CEM with cobalt chloride (CoCl2 )to reproduce hypoxia. We found that CoCl2 -altered cell viability was dose-dependently reversed using HCy. In turn, the HCy effect was inhibited using DL-propargylglycine, a specific inhibitor of the hydrogen sulphide (H2 S)-synthesizing enzyme cystathionine-γ-lyase involved in HCy catabolism. We then addressed the intracellular metabolic pathway of adenosine and HCy, and the role of the adenosine A2A receptor (A2 A R). We observed that: (i) hypoxic conditions lowered the intracellular concentration of HCy by increasing adenosine production, which resulted in high A2 A R expression and 3', 5'-cyclic adenosine monophosphate production; (ii) increasing intracellular HCy concentration reversed the hypoxia-induced adenosinergic signalling despite high adenosine concentration by promoting both S-adenosylhomocysteine and H2 S production; (iii) DL-propargylglycine that inhibits H2 S production abolished the HCy effect. Together, these data suggest that high HCy levels prevent, via H2 S production and the resulting down-regulation of A2 A R expression, the hypoxia-induced adenosinergic alteration of lymphocyte viability. We point out the relevance of these mechanisms in the pathophysiology of cardiovascular diseases., (© 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Severe acute malnutrition (SAM) is associated with inadequate diet, low levels of plasma antioxidants and gut microbiota alterations. The link between gut redox and microbial alterations, however, remains unexplored. By sequencing the gut microbiomes of 79 children of varying nutritional status from three centers in Senegal and Niger, we found a dramatic depletion of obligate anaerobes in malnutrition. This was confirmed in an individual patient data meta-analysis including 107 cases and 77 controls from 5 different African and Asian countries. Specifically, several species of the Bacteroidaceae, Eubacteriaceae, Lachnospiraceae and Ruminococceae families were consistently depleted while Enterococcus faecalis, Escherichia coli and Staphylococcus aureus were consistently enriched. Further analyses on our samples revealed increased fecal redox potential, decreased total bacterial number and dramatic Methanobrevibacter smithii depletion. Indeed, M. smithii was detected in more than half of the controls but in none of the cases. No causality was demonstrated but, based on our results, we propose a unifying theory linking microbiota specificity, lacking anaerobes and archaea, to low antioxidant nutrients, and lower food conversion.

Head-up tilt test is useful for exploring neurally mediated syncope. Adenosine is an ATP derivative implicated in cardiovascular disturbances that occur during head-up tilt test. The aim of the present study was to investigate the impact of hyperoxia on adenosine plasma level and on hemodynamic changes induced by head-up tilt testing.Seventeen healthy male volunteers (mean age 35 ± 11 years) were included in the study. The experiment consisted of 2 head-up tilt tests, 1 session with subjects breathing, through a mask, medical air (FiO2 = 21%) and 1 session with administration of pure oxygen (FiO2 = 100%) in double-blind manner. Investigations included continuous monitoring of hemodynamic data and measurement of plasma adenosine levels.No presyncope or syncope was found in 15 of the 17 volunteers. In these subjects, a slight decrease in systolic blood pressure was recorded during orthostatic stress performed under medical air exposure. In contrast, hyperoxia led to increased systolic blood pressure during orthostatic stress when compared with medical air. Furthermore, mean adenosine plasma levels decreased during hyperoxic exposure before (0.31 ± 0.08 μM) and during head-up tilt test (0.33 ± 0.09 μM) when compared with baseline (0.6 ± 0.1 μM). Adenosine plasma level was unchanged during medical air exposure at rest (0.6 ± 0.1 μM), and slightly decreased during orthostatic stress. In 2 volunteers, the head-up tilt test induced a loss of consciousness when breathing air. In these subjects, adenosine plasma level increased during orthostatic stress. In contrast, during hyperoxic exposure, the head-up tilt test did not induce presyncope or syncope. In these 2 volunteers, biological study demonstrated a decrease in adenosine plasma level at both baseline and during orthostatic stress for hyperoxic exposure compared with medical air.These results suggest that hyperoxia was able to increase blood pressure during head-up tilt test via a decrease in plasma adenosine concentration. Our results also suggest that adenosine receptor antagonists are worth trying in neurocardiogenic syncope.

The nucleoside adenosine acts on the nervous and cardiovascular systems via the A2A receptor (A2AR). In response to oxygen level in tissues, adenosine plasma concentration is regulated in particular via its synthesis by CD73 and via its degradation by adenosine deaminase (ADA). The cell-surface endopeptidase CD26 controls the concentration of vasoactive and antioxidant peptides and hence regulates the oxygen supply to tissues and oxidative stress response. Although overexpression of adenosine, CD73, ADA, A2AR, and CD26 in response to hypoxia is well documented, the effects of hyperoxic and hyperbaric conditions on these elements deserve further consideration. Rats and a murine Chem-3 cell line that expresses A2AR were exposed to 0.21 bar O2, 0.79 bar N2 (terrestrial conditions; normoxia); 1 bar O2 (hyperoxia); 2 bar O2 (hyperbaric hyperoxia); 0.21 bar O2, 1.79 bar N2 (hyperbaria). Adenosine plasma concentration, CD73, ADA, A2AR expression, and CD26 activity were addressed in vivo, and cAMP production was addressed in cellulo. For in vivo conditions, 1) hyperoxia decreased adenosine plasma level and T cell surface CD26 activity, whereas it increased CD73 expression and ADA level; 2) hyperbaric hyperoxia tended to amplify the trend; and 3) hyperbaria alone lacked significant influence on these parameters. In the brain and in cellulo, 1) hyperoxia decreased A2AR expression; 2) hyperbaric hyperoxia amplified the trend; and 3) hyperbaria alone exhibited the strongest effect. We found a similar pattern regarding both A2AR mRNA synthesis in the brain and cAMP production in Chem-3 cells. Thus a high oxygen level tended to downregulate the adenosinergic pathway and CD26 activity. Hyperbaria alone affected only A2AR expression and cAMP production. We discuss how such mechanisms triggered by hyperoxygenation can limit, through vasoconstriction, the oxygen supply to tissues and the production of reactive oxygen species., (Copyright © 2015 the American Physiological Society.)

Background: Plasma troponin is a risk factor for cardiac events in various populations. We evaluated the determinants and predictive value of plasma cardiac troponin I (cTnI) during the long-term follow-up of heart transplantation., Methods and Results: We prospectively measured cTnI in 100 heart transplant recipients, 13.0 ± 6.0 years after transplantation, during a routine visit including echocardiography and laboratory measurements. The patients were followed for 21.3 ± 4.9 months after this troponin measurement. cTnI ≥0.006 μg/L (detection threshold) was found in 37 of these 100 patients. Plasma troponin significantly increased with the presence and severity of coronary lesions detected by means of coronary angiography and was significantly associated with age, left ventricular mass, history of post-transplantation heart failure, body mass index, and plasma creatinine. Of 37 patients with cTnI ≥0.006 μg/L, 13 had a cardiac event during follow-up compared with 2 of 63 patients with cTnI <0.006 μg/L (P < .0001). The relation between cTnI and cardiac events remained significant in multivariate analysis., Conclusions: cTnI is frequently detectable during long-term follow-up after heart transplantation and is associated with chronic graft rejection and renal failure. A detectable cTnI may help identify heart transplant recipients at high risk of cardiac events., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Hypoxia affects inflammation by modulating T-cell activation via the adenosinergic system. We supposed that, in turn, inflammation influences cell hypoxic behavior and that stimulation of T-cells in inflammatory conditions involves the concerted action of the nuclear factor κB (NF-κB) and the related hypoxia-inducible factor 1α (HIF-1α) on the adenosinergic system. We addressed this hypothesis by monitoring both transcription factors and four adenosinergic signaling parameters - namely adenosine, adenosine deaminase (ADA), adenosine A2A receptor (A2AR) and cAMP - in T-cells stimulated using phorbol myristate acetate and phytohemagglutinin and submitted to hypoxic conditions which were mimicked using CoCl2 treatment. We found that cell viability was more altered in stimulated than in resting cells under hypoxia. Detailed analysis showed that: i) NF-κB activation remained at basal level in resting hypoxic cells but greatly increased following stimulation, stimulated hypoxic cells exhibiting the higher level; ii) HIF-1α production induced by hypoxia was boosted via NF-κB activation in stimulated cells whereas hypoxia increased HIF-1α production in resting cells without further activating NF-κB; iii) A2AR expression and cAMP production increased in stimulated hypoxic cells whereas adenosine level remained unchanged due to ADA regulation; and iv) the presence of H2S, an endogenous signaling molecule in inflammation, reversed the effect of stimulation on cell viability by down-regulating the activity of transcription factors and adenosinergic immunosuppression. We also found that: i) the specific A2AR agonist CGS-21680 increased the suppressive effect of hypoxia on stimulated T-cells, the antagonist ZM-241385 exhibiting the opposite effect; and ii) Rolipram, a selective inhibitor of cAMP-specific phosphodiesterase 4, and 8-Br-cAMP, a cAMP analog which preferentially activates cAMP-dependent protein kinase A (PKA), increased T-cell immunosuppression whereas H-89, a potent and selective inhibitor of cAMP-dependent PKA, restored cell viability. Together, these data indicate that inflammation enhances T-cell sensitivity to hypoxia via NF-κB activation. This process upregulates A2AR expression and enhances cAMP production and PKA activation, resulting in adenosinergic T-cell immunosuppression that can be modulated via H2S., (Copyright © 2014 Elsevier Inc. All rights reserved.)