Fungal microbiota in newborn infants with and without respiratory distress syndrome.

BACKGROUND: Pneumocytis jirovecii infection in preterm newborns has recently been associated with neonatal respiratory distress syndrome and bronchopulmonary dysplasia. Changes in the bacterial microbiota of the airways have also been described in infants with bronchopulmonary dysplasia. However, until now there has been no information on the airway mycobiota in newborns. The purpose of this study was to describe the airway mycobiota in term and preterm newborns and its possible association with respiratory distress syndrome. METHODS: Twenty-six matched preterm newborns with and without respiratory distress syndrome were studied, as well as 13 term babies. The identification of the fungal microbiota was carried out using molecular procedures in aspirated nasal samples at birth. RESULTS: The ascomycota phylum was identified in 89.7% of newborns, while the basidiomycota phylum was found in 33.3%. Cladosporium was the predominant genus in both term and preterm infants 38.4% vs. 73% without statistical differences. Candida sake and Pneumocystis jirovecii were only found in preterm infants, suggesting a potential relationship with the risk of prematurity. CONCLUSIONS: This is the first report to describe the fungal microbiota of the airways in term and preterm infants with and without respiratory distress syndrome. Although no differences have been observed, the number of cases analyzed could be small to obtain conclusive results, and more studies are needed to understand the role of the fungal microbiota of the airways in neonatal respiratory pathology.

Effects of exercise on platelet reactivity after myocardial infarction: a randomized clinical trial.

Exercise training (ET) can lower platelet reactivity in patients with cardiovascular risk factors. However, the effects of ET on platelet reactivity in higher-risk patients is unknown. The aim of this study was to evaluate the effects of ET on platelet reactivity in patients with recent myocardial infarction (MI). Ninety patients were randomly assigned 1 month post-MI to the intervention (patients submitted to a supervised ET program) or control group. All patients were on dual antiplatelet therapy (DAPT). Platelet reactivity by VerifyNow-P2Y12 (measured by P2Y12 reaction units - PRUs) test was determined at baseline and at the end of 14 ± 2 weeks of follow-up at rest (primary endpoint), and multiplate electrode aggregometry (MEA) adenosine diphosphate (ADP) and aspirin (ASPI) tests were performed immediately before and after the maximal cardiopulmonary exercise test (CPET) at the same time points (secondary endpoints). Sixty-five patients (mean age 58.9 ± 10 years; 73.8% men; 60% ST elevation MI) completed follow-up (control group, n = 31; intervention group, n = 34). At the end of the follow-up, the mean platelet reactivity was 172.8 ± 68.9 PRUs and 166.9 ± 65.1 PRUs for the control and intervention groups, respectively (p = .72). Platelet reactivity was significantly increased after the CPET compared to rest at the beginning and at the end of the 14-week follow-up (among the intervention groups) by the MEA-ADP and MEA-ASPI tests (p < .01 for all analyses). In post-MI patients on DAPT, 14 weeks of supervised ET did not reduce platelet reactivity. Moreover, platelet reactivity was increased after high-intensity exercise (ClinicalTrials.gov: NCT02958657; https://clinicaltrials.gov/ct2/show/NCT02958657).

What is the context? Platelet reactivity is reduced after exercise training in healthy individuals and patients with cardiovascular risk factors, but the effect in higher-risk patients is unknown.High-intensity exercise in untrained individuals increases platelet reactivity. The effect of dual antiplatelet therapy in inhibiting exercise-induced hyperreactivity is poorly understood.What's new?Exercise training did not reduce platelet reactivity in post-myocardial infarction patients.High-intensity exercise increased platelet reactivity in post-myocardial infarction patients on dual antiplatelet therapy.Exercise training did not attenuate the exercise-induced increase in platelet reactivity.What's the impact?The study suggests that strenuous exercise, if indicated, should be applied carefully to patients with high risk of recurrent ischemic events, even if on optimal medical therapy and after being trained.

Platelet Reactivity and Coagulation Markers in Patients with COVID-19.

INTRODUTION: COVID-19 is associated with an increased risk of thrombotic events. However, the contribution of platelet reactivity (PR) to the aetiology of the increased thrombotic risk associated with COVID-19 remains unclear. Our aim was to evaluate PR in stable patients diagnosed with COVID-19 and hospitalized with respiratory symptoms (mainly dyspnoea and dry cough), in comparison with a control group comprised of non-hospitalized healthy controls. METHODS: Observational, case control study that included patients with confirmed COVID-19 (COVID-19 group, n = 60) and healthy individuals matched by age and sex (control group, n = 60). Multiplate electrode aggregometry (MEA) tests were used to assess PR with adenosine diphosphate (MEA-ADP, low PR defined as < 53 AUC), arachidonic acid (MEA-ASPI, low PR < 86 AUC) and thrombin receptor-activating peptide 6 (MEA-TRAP, low PR < 97 AUC) in both groups. RESULTS: The rates of low PR with MEA-ADP were 27.5% in the COVID-19 group and 21.7% in the control group (OR = 1.60, p = 0.20); with MEA-ASPI, the rates were, respectively, 37.5% and 22.5% (OR = 3.67, p < 0.001); and with MEA-TRAP, the incidences were 48.5% and 18.8%, respectively (OR = 9.58, p < 0.001). Levels of D-dimer, fibrinogen, and plasminogen activator inhibitor 1 (PAI-1) were higher in the COVID-19 group in comparison with the control group (all p < 0.05). Thromboelastometry was utilized in a subgroup of patients and showed a hypercoagulable state in the COVID-19 group. CONCLUSION: Patients hospitalized with non-severe COVID-19 had lower PR compared to healthy controls, despite having higher levels of D-dimer, fibrinogen, and PAI-1, and hypercoagulability by thromboelastometry. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT04447131.

Associação entre Terapia com Estatinas e Menor Incidência de Hiperglicemia em Pacientes Internados com Síndromes Coronarianas Agudas / Association between Statin Therapy and Lower Incidence of Hyperglycemia in Patients Hospitalized with Acute Coronary Syndromes

Resumo Fundamento O maior risco de se desenvolver diabetes com o uso de estatinas é um desafio para a segurança do uso dessa classe de medicamentos em longo prazo. No entanto, poucos estudos analisaram essa questão durante síndromes coronarianas agudas (SCA). Objetivos Investigar a associação entre início precoce da terapia com estatina e níveis de glicemia em pacientes admitidos com SCA. Métodos Este foi um estudo retrospectivo de pacientes hospitalizados por SCA. Pacientes que nunca haviam usado estatinas foram incluídos e divididos segundo uso ou não de estatina nas primeiras 24 horas de internação. O desfecho primário foi a incidência de hiperglicemia na internação (definida como pico de glicemia > 200mg/dL). Modelos de regressão logística e modelos lineares multivariados foram usados para ajuste quanto a fatores de confusão e um modelo de pareamento por escore de propensão foi desenvolvido para comparações entre os dois grupos de interesses. Um valor de p menor que 0,05 foi considerado estatisticamente significativo. Resultados Um total de 2357 pacientes foram incluídos, 1704 deles alocados no grupo que receberam estatinas e 653 no grupo que não receberam estatinas nas primeiras 24 horas de internação. Após os ajustes, uso de estatina nas primeiras 24 horas foi associado com uma menor incidência de hiperglicemia durante a internação (OR ajustado = 0,61, IC95% 0,46-0,80; p < 0,001) e menor necessidade de uso de insulina (OR ajustado = 0,56, IC 95% 0,41-0,76; p < 0,001). Essas associações mantiveram-se similares nos modelos de pareamento por escore de propensão, bem como após análises de sensibilidade, como exclusão de pacientes que desenvolveram choque cardiogênico, infecção grave ou pacientes que foram a óbito durante a internação hospitalar. Conclusões Entre os pacientes internados com SCA que não receberam estatinas previamente, a terapia precoce com estatina associou-se independentemente com menor incidência de hiperglicemia durante a internação. (Arq Bras Cardiol. 2021; 116(2):285-294)

Abstract Background Increased risk of new-onset diabetes with statins challenges the long-term safety of this drug class. However, few reports have analyzed this issue during acute coronary syndromes (ACS). Objective To explore the association between early initiation of statin therapy and blood glucose levels in patients admitted with ACS. Methods This was a retrospective analysis of patients hospitalized with ACS. Statin-naïve patients were included and divided according to their use or not of statins within the first 24 hours of hospitalization. The primary endpoint was incidence of in-hospital hyperglycemia (defined as peak blood glucose > 200 mg/dL). Multivariable linear and logistic regression models were used to adjust for confounders, and a propensity-score matching model was developed to further compare both groups of interest. A p-value of less than 0.05 was considered statistically significant. Results A total of 2,357 patients were included, 1,704 of them allocated in the statin group and 653 in the non-statin group. After adjustments, statin use in the first 24 hours was associated with a lower incidence of in-hospital hyperglycemia (adjusted OR=0.61, 95% CI 0.46-0.80; p < 0.001) and lower need for insulin therapy (adjusted OR = 0.56, 95% CI 0.41-0.76; p < 0.001). These associations remained similar in the propensity-score matching models, as well as after several sensitivity analyses, such as after excluding patients who developed cardiogenic shock, severe infection or who died during index-hospitalization. Conclusions Among statin-naïve patients admitted with ACS, early statin therapy was independently associated with lower incidence of in-hospital hyperglycemia. (Arq Bras Cardiol. 2021; 116(2):285-294)

Factors associated with actively working in the very long-term following acute coronary syndrome.

OBJECTIVES: Returning to work after an episode of acute coronary syndrome (ACS) is challenging for many patients, and has both personal and social impacts. There are limited data regarding the working status in the very long-term after ACS. METHODS: We retrospectively analyzed 1,632 patients who were working prior to hospitalization for ACS in a quaternary hospital and were followed-up for up to 17 years. Adjusted models were developed to analyze the variables independently associated with actively working at the last contact, and a prognostic predictive index for not working at follow-up was developed. RESULTS: The following variables were significantly and independently associated with actively working at the last contact: age>median (hazard-ratio [HR], 0.76, p<0.001); male sex (HR, 1.52, p<0.001); government health insurance (HR, 1.36, p<0.001); history of angina (HR, 0.69, p<0.001) or myocardial infarction (MI) (HR, 0.76, p=0.005); smoking (HR, 0.81, p=0.015); ST-elevation MI (HR, 0.81, p=0.021); anterior-wall MI (HR, 0.75, p=0.001); non-primary percutaneous coronary intervention (PCI) (HR, 0.77, p=0.002); fibrinolysis (HR, 0.61, p<0.001); cardiogenic shock (HR, 0.60, p=0.023); statin (HR, 3.01, p<0.001), beta-blocker (HR, 1.26, p=0.020), angiotensin-converting enzyme (ACE) inhibitor/angiotensin II receptor blocker (ARB) (HR, 1.37, p=0.001) at hospital discharge; and MI at follow-up (HR, 0.72, p=0.001). The probability of not working at the last contact ranged from 24.2% for patients with no variables, up to 80% for patients with six or more variables. CONCLUSIONS: In patients discharged after ACS, prior and in-hospital clinical variables, as well as the quality of care at discharge, have a great impact on the long-term probability of actively working.

Insulin requires A2B adenosine receptors to modulate the L-arginine/nitric oxide signalling in the human fetoplacental vascular endothelium from late-onset preeclampsia.

Late-onset preeclampsia (LOPE) associates with reduced umbilical vein reactivity and endothelial nitric oxide synthase (eNOS) activity but increased human cationic amino acid (hCAT-1)-mediated L-arginine transport involving A2A adenosine receptor in the fetoplacental unit. This study addresses the A2B adenosine receptor (A2BAR)-mediated response to insulin in the fetoplacental vasculature from LOPE. Umbilical veins and HUVECs were obtained from women with normal (n = 37) or LOPE (n = 35) pregnancies. Umbilical vein rings reactivity to insulin was assayed in the absence or presence of adenosine and MRS-1754 (A2BAR antagonist) in a wire myograph. HUVECs were exposed to insulin, MRS-1754, BAY60-6583 (A2BAR agonist), NECA (general adenosine receptors agonist) or NG-nitro-L-arginine methyl ester (NOS inhibitor). A2BAR, hCAT-1, total and phosphorylated eNOS, Akt and p44/42mapk protein abundance were determined by Western blotting. Insulin receptors A (IR-A) and B (IR-B), eNOS and hCAT-1 mRNA were determined by qPCR. Firefly/Renilla luciferase assay was used to determine -1606 bp SLC7A1 (hCAT-1) promoter activity. L-Citrulline content was measured by HPLC, L-[3H]citrulline formation from L-[3H]arginine by the Citrulline assay, and intracellular cGMP by radioimmunoassay. LOPE-reduced dilation of vein rings to insulin was restored by MRS-1754. HUVECs from LOPE showed higher A2BAR, hCAT-1, and IR-A expression, Akt and p44/42mapk activation, and lower NOS activity. MRS-1754 reversed the LOPE effect on A2BAR, hCAT-1, Akt, and eNOS inhibitory phosphorylation. Insulin reversed the LOPE effect on A2BAR, IR-A and eNOS, but increased hCAT-1-mediated transport. Thus, LOPE alters endothelial function, causing an imbalance in the L-arginine/NO signalling pathway to reduce the umbilical vein dilation to insulin requiring A2BAR activation in HUVECs.

Factors associated with actively working in the very long-term following acute coronary syndrome

OBJECTIVES: Returning to work after an episode of acute coronary syndrome (ACS) is challenging for many patients, and has both personal and social impacts. There are limited data regarding the working status in the very long-term after ACS. METHODS: We retrospectively analyzed 1,632 patients who were working prior to hospitalization for ACS in a quaternary hospital and were followed-up for up to 17 years. Adjusted models were developed to analyze the variables independently associated with actively working at the last contact, and a prognostic predictive index for not working at follow-up was developed. RESULTS: The following variables were significantly and independently associated with actively working at the last contact: age>median (hazard-ratio [HR], 0.76, p<0.001); male sex (HR, 1.52, p<0.001); government health insurance (HR, 1.36, p<0.001); history of angina (HR, 0.69, p<0.001) or myocardial infarction (MI) (HR, 0.76, p=0.005); smoking (HR, 0.81, p=0.015); ST-elevation MI (HR, 0.81, p=0.021); anterior-wall MI (HR, 0.75, p=0.001); non-primary percutaneous coronary intervention (PCI) (HR, 0.77, p=0.002); fibrinolysis (HR, 0.61, p<0.001); cardiogenic shock (HR, 0.60, p=0.023); statin (HR, 3.01, p<0.001), beta-blocker (HR, 1.26, p=0.020), angiotensin-converting enzyme (ACE) inhibitor/angiotensin II receptor blocker (ARB) (HR, 1.37, p=0.001) at hospital discharge; and MI at follow-up (HR, 0.72, p=0.001). The probability of not working at the last contact ranged from 24.2% for patients with no variables, up to 80% for patients with six or more variables. CONCLUSIONS: In patients discharged after ACS, prior and in-hospital clinical variables, as well as the quality of care at discharge, have a great impact on the long-term probability of actively working.

Relation of High Lipoprotein (a) Concentrations to Platelet Reactivity in Individuals with and Without Coronary Artery Disease.

INTRODUCTION: Lipoprotein (a) [Lp(a)] is a risk factor for coronary artery disease (CAD). To the best of our knowledge, this is the first study addressing the relationship between Lp(a) and platelet reactivity in primary and secondary prevention. METHODS: Lp(a) was evaluated in 396 individuals with (82.3%) and without (17.7%) obstructive CAD. The population was divided into two groups according to Lp(a) concentrations with a cutoff value of 50 mg/dL. The primary objective was to evaluate the association between Lp(a) and adenosine diphosphate (ADP)-induced platelet reactivity using the VerifyNow™ P2Y12 assay. Platelet reactivity was also induced by arachidonic acid and collagen-epinephrine (C-EPI) and assessed by Multiplate™, platelet function analyzer™ 100 (PFA-100), and light transmission aggregometry (LTA) assays. Secondary objectives included the assessment of the primary endpoint in individuals with or without CAD. RESULTS: Overall, 294 (74.2%) individuals had Lp(a) < 50 mg/dL [median (IQR) 13.2 (5.8-27.9) mg/dL] and 102 (25.8%) had Lp(a) ≥ 50 mg/dL [82.5 (67.6-114.5) mg/dL], P < 0.001. Univariate analysis in the entire population revealed no differences in ADP-induced platelet reactivity between individuals with Lp(a) ≥ 50 mg/dL (249.4 ± 43.8 PRU) versus Lp(a) < 50 mg/dL (243.1 ± 52.2 PRU), P = 0.277. Similar findings were present in individuals with (P = 0.228) and without (P = 0.669) CAD, and regardless of the agonist used or method of analysis (all P > 0.05). Finally, multivariable analysis did not show a significant association between ADP-induced platelet reactivity and Lp(a) ≥ 50 mg/dL [adjusted OR = 1.00 [(95% CI 0.99-1.01), P = 0.590]. CONCLUSION: In individuals with or without CAD, Lp(a) ≥ 50 mg/dL was not associated with higher platelet reactivity.

Maternal supraphysiological hypercholesterolemia associates with endothelial dysfunction of the placental microvasculature.

Maternal physiological or supraphysiological hypercholesterolemia (MPH, MSPH) occurs during pregnancy. MSPH is associated with foetal endothelial dysfunction and atherosclerosis. However, the potential effects of MSPH on placental microvasculature are unknown. The aim of this study was to determine whether MSPH alters endothelial function in the placental microvasculature both ex vivo in venules and arterioles from the placental villi and in vitro in primary cultures of placental microvascular endothelial cells (hPMEC). Total cholesterol < 280 mg/dL indicated MPH, and total cholesterol ≥280 mg/dL indicated MSPH. The maximal relaxation to histamine, calcitonin gene-related peptide and adenosine was reduced in MSPH venule and arteriole rings. In hPMEC from MSPH placentas, nitric oxide synthase (NOS) activity and L-arginine transport were reduced without changes in arginase activity or the protein levels of endothelial NOS (eNOS), human cationic amino acid 1 (hCAT-1), hCAT-2A/B or arginase II compared with hPMEC from MPH placentas. In addition, it was shown that adenosine acts as a vasodilator of the placental microvasculature and that NOS is active in hPMEC. We conclude that MSPH alters placental microvascular endothelial function via a NOS/L-arginine imbalance. This work also reinforces the concept that placental endothelial cells from the macro- and microvasculature respond differentially to the same pathological condition.

Akt/mTOR Role in Human Foetoplacental Vascular Insulin Resistance in Diseases of Pregnancy.

Insulin resistance is characteristic of pregnancies where the mother shows metabolic alterations, such as preeclampsia (PE) and gestational diabetes mellitus (GDM), or abnormal maternal conditions such as pregestational maternal obesity (PGMO). Insulin signalling includes activation of insulin receptor substrates 1 and 2 (IRS1/2) as well as Src homology 2 domain-containing transforming protein 1, leading to activation of 44 and 42 kDa mitogen-activated protein kinases and protein kinase B/Akt (Akt) signalling cascades in the human foetoplacental vasculature. PE, GDM, and PGMO are abnormal conditions coursing with reduced insulin signalling, but the possibility of the involvement of similar cell signalling mechanisms is not addressed. This review aimed to determine whether reduced insulin signalling in PE, GDM, and PGMO shares a common mechanism in the human foetoplacental vasculature. Insulin resistance in these pathological conditions results from reduced Akt activation mainly due to inhibition of IRS1/2, likely due to the increased activity of the mammalian target of rapamycin (mTOR) resulting from lower activity of adenosine monophosphate kinase. Thus, a defective signalling via Akt/mTOR in response to insulin is a central and common mechanism of insulin resistance in these diseases of pregnancy. In this review, we summarise the cell signalling mechanisms behind the insulin resistance state in PE, GDM, and PGMO focused in the Akt/mTOR signalling pathway in the human foetoplacental endothelium.

Preeclampsia associates with RECK-dependent decrease in human trophoblasts migration and invasion.

INTRODUCTION: Preeclampsia is characterized by reduced invasion capacity of trophoblasts involving lower matrix metalloproteinase (MMP) activity. Cell invasion is reduced by reversion-inducing-cysteine-rich protein with Kazal motifs (RECK), a plasma membrane protein that inhibits MMP in several cell types. However, it is unknown whether this mechanism happens in the human placenta from preeclampsia. The hypothesis of this study sustains that RECK expression is increased leading to reduced trophoblasts invasion in preeclampsia. METHODS: RECK expression in the human first trimester trophoblast cell line HTR8/SvNeo and in placentas from normal (n = 4) and preeclampsia (n = 4) pregnancies was evaluated by Western blot and immunofluorescence. MMP-dependent gelatin hydrolyzation was measured by in situ zymography and gelatinase assay in placental and cell extracts. RECK was overexpressed (plasmidial vector transfection) or partially reduced (shRNA) to evaluate its role in HTR8/SVneo cell migration and invasion. RESULTS: RECK was expressed in trophoblasts layer in human placentas. Preeclampsia resulted in higher placental RECK protein abundance, reduced MMP function, and higher level of fibronectin (a MMP substrate) compared with placentas from normal pregnancies. RECK is also expressed in HTR-8/SVneo cells. Reduced RECK expression resulted in higher MMP-dependent gelatin hydrolyzation, associated to higher migration and invasion of HTR8/SVneo cells. However, RECK overexpression associated with reduced hydrolyzation, cell migration and invasion. DISCUSSION: RECK is overexpressed in human trophoblasts from preeclampsia and may be responsible of this disease-associated lower migration and invasion of this cell type.

Maternal insulin therapy does not restore foetoplacental endothelial dysfunction in gestational diabetes mellitus.

Pregnant women diagnosed with gestational diabetes mellitus subjected to diet (GDMd) that do not reach normal glycaemia are passed to insulin therapy (GDMi). GDMd associates with increased human cationic amino acid transporter 1 (hCAT-1)-mediated transport of L-arginine and nitric oxide synthase (NOS) activity in foetoplacental vasculature, a phenomenon reversed by exogenous insulin. Whether insulin therapy results in reversal of the GDMd effect on the foetoplacental vasculature is unknown. We assayed whether insulin therapy normalizes GDMd-associated foetoplacental endothelial dysfunction. Primary cultures of human umbilical vein endothelial cells (HUVECs) from GDMi pregnancies were used to assay L-arginine transport kinetics, NOS activity, p44/42mapk and protein kinase B/Akt activation, and umbilical vein rings reactivity. HUVECs from GDMi or GDMd show increased hCAT-1 expression and maximal transport capacity, NOS activity, and eNOS, and p44/42mapk, but not Akt activator phosphorylation. Dilation in response to insulin or calcitonin-gene related peptide was impaired in umbilical vein rings from GDMi and GDMd pregnancies. Incubation of HUVECs in vitro with insulin (1 nmol/L) restored hCAT-1 and eNOS expression and activity, and eNOS and p44/42mapk activator phosphorylation. Thus, maternal insulin therapy does not seem to reverse GDMd-associated alterations in human foetoplacental vasculature.

Adenosine receptors: Modulators of lipid availability that are controlled by lipid levels.

Adenosine as well as agonists and antagonists for the four adenosine receptor subtypes (A1R, A2AR, A2BR and A3R) play a role in several key physiological and pathophysiological processes, including the regulation of vascular tone, thrombosis, immune response, inflammation, and angiogenesis. This review focuses on the adenosine-mediated regulation of lipid availability in the cell and in the systemic circulation as well in humans and animal models. Therefore, adenosine, mainly by acting on A1R, inhibits lipolysis activity, leading to reduction of the circulating fatty acid levels. This nucleoside can also participate in the early development of atherosclerosis by inhibiting the formation of foam cells via stimulation of cholesterol efflux through A2AR expressed on macrophages and reduction of the inflammatory process by activating A2AR and A2BR. Adenosine also appears to modulate intracellular cholesterol availability in Niemann-Pick type C1 disease and Alzheimer disease via A2AR and A3, respectively. Remarkably, the role of adenosine receptors in the regulation of plasma total cholesterol and triglyceride levels has been studied in animal models. Thus, an anti-atherogenic role for A2BR as well as a pro-atherogenic role of A2AR and A1 have been proposed; A3R has not been shown to participate in the control of lipid levels or the development of atherosclerosis. Surprisingly, and despite the role of A2A in the inhibition of foam cell formation among isolated cells, this receptor appears to be pro-atherogenic in mice. Remarkably, the role of adenosine receptors in human dyslipidaemia and atherosclerosis must to be elucidated. Additionally, it has been reported that increased lipid levels impair the effects of adenosine/adenosine receptors in controlling vascular tone, and we speculate on the possibility that this impairment could be due to alterations in the composition of the membrane microdomains where the adenosine receptors are located. Finally, a possible role for adenosine/adenosine receptors in the phenomena of dyslipidaemia in pregnancy has been proposed.

Adenosine and preeclampsia.

Adenosine is an endogenous nucleoside with pleiotropic effects in different physiological processes including circulation, renal blood flow, immune function, or glucose homeostasis. Changes in adenosine membrane transporters, adenosine receptors, and corresponding intracellular signalling network associate with development of pathologies of pregnancy, including preeclampsia. Preeclampsia is a cause of maternal and perinatal morbidity and mortality affecting 3-5% of pregnancies. Since the proposed mechanisms of preeclampsia development include adenosine-dependent biological effects, adenosine membrane transporters and receptors, and the associated signalling mechanisms might play a role in the pathophysiology of preeclampsia. Preeclampsia associates with increased adenosine concentration in the maternal blood and placental tissue, likely due to local hypoxia and ischemia (although not directly demonstrated), microthrombosis, increased catecholamine release, and platelet activation. In addition, abnormal expression and function of equilibrative nucleoside transporters is described in foetoplacental tissues from preeclampsia; however, the role of adenosine receptors in the aetiology of this disease is not well understood. Adenosine receptors activation may be related to abnormal trophoblast invasion, angiogenesis, and ischemia/reperfusion mechanisms in the placenta from preeclampsia. These mechanisms may explain only a low fraction of the associated abnormal transformation of spiral arteries in preeclampsia, triggering cellular stress and inflammatory mediators release from the placenta to the maternal circulation. Although increased adenosine concentration in preeclampsia may be a compensatory or adaptive mechanism favouring placental angiogenesis, a poor angiogenic state is found in preeclampsia. Thus, preeclampsia-associated complications might affect the cell response to adenosine due to altered expression and activity of adenosine receptors, membrane transporters, or cell signalling mechanisms. This review summarizes the evidence available on the potential involvement of the adenosine in the clinical, pathophysiology, and therapeutic features of preeclampsia.

Molecular implications of adenosine in obesity.

Adenosine has broad activities in organisms due to the existence of multiple receptors, the differential adenosine concentrations necessary to activate these receptors and the presence of proteins able to synthetize, degrade or transport this nucleoside. All adenosine receptors have been reported to be involved in glucose homeostasis, inflammation, adipogenesis, insulin resistance, and thermogenesis, indicating that adenosine could participate in the process of obesity. Since adenosine seems to be associated with several effects, it is plausible that adenosine participates in the initiation and development of obesity or may function to prevent it. Thus, the purpose of this review was to explore the involvement of adenosine in adipogenesis, insulin resistance and thermogenesis, with the aim of understanding how adenosine could be used to avoid, treat or improve the metabolic state of obesity. Treatment with specific agonists and/or antagonists of adenosine receptors could reverse the obesity state, since adenosine receptors normalizes several mechanisms involved in obesity, such as lipolysis, insulin sensitivity and thermogenesis. Furthermore, obesity is a preventable state, and the specific activation of adenosine receptors could aid in the prevention of obesity. Nevertheless, for the treatment of obesity and its consequences, more studies and therapeutic strategies in addition to adenosine are necessary.

Insulin/adenosine axis linked signalling.

Regulation of blood flow depends on systemic and local release of vasoactive molecules such as insulin and adenosine. These molecules cause vasodilation by activation of plasma membrane receptors at the vascular endothelium. Adenosine activates at least four subtypes of adenosine receptors (A1AR, A2AAR, A2BAR, A3AR), of which A2AAR and A2BAR activation leads to increased cAMP level, generation of nitric oxide, and relaxation of the underlying smooth muscle cell layer. Vasodilation caused by adenosine also depends on plasma membrane hyperpolarization due to either activation of intermediate-conductance Ca2+-activated K+ channels in vascular smooth muscle or activation of ATP-activated K+ channels in the endothelium. Adenosine also causes vasoconstriction via a mechanism involving A1AR activation resulting in lower cAMP level and increased thromboxane release. Insulin has also a dual effect causing NO-dependent vasodilation, but also sympathetic activity- and increased endothelin 1 release-dependent vasoconstriction. Interestingly, insulin effects require or are increased by activation or inactivation of adenosine receptors. This is phenomenon described for d-glucose and l-arginine transport where A2AAR and A2BAR play a major role. Other studies show that A1AR activation could reduce insulin release from pancreatic ß-cells. Whether adenosine modulation of insulin biological effect is a phenomenon that depends on co-localization of adenosine receptors and insulin receptors, and adenosine plasma membrane transporters is something still unclear. This review summarizes findings addressing potential involvement of adenosine receptors to modulate insulin effect via insulin receptors with emphasis in the human vasculature.

Insulin Is a Key Modulator of Fetoplacental Endothelium Metabolic Disturbances in Gestational Diabetes Mellitus.

Gestational diabetes mellitus (GDM) is a disease of the mother that associates with altered fetoplacental vascular function. GDM-associated maternal hyperglycaemia result in fetal hyperglycaemia, a condition that leads to fetal hyperinsulinemia and altered L-arginine transport and synthesis of nitric oxide, i.e., endothelial dysfunction. These alterations in the fetoplacental endothelial function are present in women with GDM that were under diet or insulin therapy. Since these women and their newborn show normal glycaemia at term, other factors or conditions could be altered and/or not resolved by restoring normal level of circulating D-glucose. GDM associates with metabolic disturbances, such as abnormal handling of the locally released vasodilator adenosine, and biosynthesis and metabolism of cholesterol lipoproteins, or metabolic diseases resulting in endoplasmic reticulum stress and altered angiogenesis. Insulin acts as a potent modulator of all these phenomena under normal conditions as reported in primary cultures of cells obtained from the human placenta; however, GDM and the role of insulin regarding these alterations in this disease are poorly understood. This review focuses on the potential link between insulin and endoplasmic reticulum stress, hypercholesterolemia, and angiogenesis in GDM in the human fetoplacental vasculature. Based in reports in primary culture placental endothelium we propose that insulin is a factor restoring endothelial function in GDM by reversing ERS, hypercholesterolaemia and angiogenesis to a physiological state involving insulin activation of insulin receptor isoforms and adenosine receptors and metabolism in the human placenta from GDM pregnancies.

Leptin Induces Oxidative Stress Through Activation of NADPH Oxidase in Renal Tubular Cells: Antioxidant Effect of L-Carnitine.

Leptin is a protein involved in the regulation of food intake and in the immune and inflammatory responses, among other functions. Evidences demonstrate that obesity is directly associated with high levels of leptin, suggesting that leptin may directly link obesity with the elevated cardiovascular and renal risk associated with increased body weight. Adverse effects of leptin include oxidative stress mediated by activation of NADPH oxidase. The aim of this study was to evaluate the effect of L-carnitine (LC) in rat renal epithelial cells (NRK-52E) exposed to leptin in order to generate a state of oxidative stress characteristic of obesity. Leptin increased superoxide anion (O2 (•) -) generation from NADPH oxidase (via PI3 K/Akt pathway), NOX2 expression and nitrotyrosine levels. On the other hand, NOX4 expression and hydrogen peroxide (H2 O2 ) levels diminished after leptin treatment. Furthermore, the expression of antioxidant enzymes, catalase, and superoxide dismutase, was altered by leptin, and an increase in the mRNA expression of pro-inflammatory factors was also found in leptin-treated cells. LC restored all changes induced by leptin to those levels found in untreated cells. In conclusion, stimulation of NRK-52E cells with leptin induced a state of oxidative stress and inflammation that could be reversed by preincubation with LC. Interestingly, LC induced an upregulation of NOX4 and restored the release of its product, hydrogen peroxide, which suggests a protective role of NOX4 against leptin-induced renal damage. J. Cell. Biochem. 117: 2281-2288, 2016. © 2016 Wiley Periodicals, Inc.

A Hypothesis for the Role of RECK in Angiogenesis.

Angiogenesis is a key process by which new capillary blood vessels are formed, sustaining the supply of oxygen and other nutrients to the body allowing its growth and wound healing, among others. However, angiogenesis also associates with pathological processes, such us tumor growth. Vascular endothelial cells produce different matrix remodeling enzymes such as matrix metalloproteinases and a-disintegrin and metalloproteinases, which have both positive and negative effects on angiogenesis, regulating the cell environment and signaling. However, little is known about the regulation of the activity of these proteases during vascular development. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is a membrane-anchored inhibitor of different matrix metalloproteinases and a-disintegrin and metalloproteinases, being a critical regulator of extracellular matrix remodeling and signaling pathway, particularly Notch, which is critical for the maturation of the growing vessels. Reck knockout mice die in utero showing vascular developmental defects and massive hemorrhages. These defects were not observed in knockout mice for secreted-soluble matrix metalloproteinase inhibitors pointing to an exclusive role of RECK in vascular development and maturation since its location at the plasma membrane. Despite the above, the exact role of RECK in this process has not been clarified. This review is focused to summarize the available information on the role of RECK as membrane anchored matrix metalloproteinases and a-disintegrin and metalloproteinases inhibitor, proposing a hypothesis by which RECK play key roles in the physiology and pathophysiology of the angiogenesis processes.

Insulin reverses D-glucose-increased nitric oxide and reactive oxygen species generation in human umbilical vein endothelial cells.

Vascular tone is controlled by the L-arginine/nitric oxide (NO) pathway, and NO bioavailability is strongly affected by hyperglycaemia-induced oxidative stress. Insulin leads to high expression and activity of human cationic amino acid transporter 1 (hCAT-1), NO synthesis and vasodilation; thus, a protective role of insulin on high D-glucose-alterations in endothelial function is likely. Vascular reactivity to U46619 (thromboxane A2 mimetic) and calcitonin gene related peptide (CGRP) was measured in KCl preconstricted human umbilical vein rings (wire myography) incubated in normal (5 mmol/L) or high (25 mmol/L) D-glucose. hCAT-1, endothelial NO synthase (eNOS), 42 and 44 kDa mitogen-activated protein kinases (p42/44mapk), protein kinase B/Akt (Akt) expression and activity were determined by western blotting and qRT-PCR, tetrahydrobiopterin (BH4) level was determined by HPLC, and L-arginine transport (0-1000 µmol/L) was measured in response to 5-25 mmol/L D-glucose (0-36 hours) in passage 2 human umbilical vein endothelial cells (HUVECs). Assays were in the absence or presence of insulin and/or apocynin (nicotinamide adenine dinucleotide phosphate-oxidase [NADPH oxidase] inhibitor), tempol or Mn(III)TMPyP (SOD mimetics). High D-glucose increased hCAT-1 expression and activity, which was biphasic (peaks: 6 and 24 hours of incubation). High D-glucose-increased maximal transport velocity was blocked by insulin and correlated with lower hCAT-1 expression and SLC7A1 gene promoter activity. High D-glucose-increased transport parallels higher reactive oxygen species (ROS) and superoxide anion (O2•-) generation, and increased U46619-contraction and reduced CGRP-dilation of vein rings. Insulin and apocynin attenuate ROS and O2•- generation, and restored vascular reactivity to U46619 and CGRP. Insulin, but not apocynin or tempol reversed high D-glucose-increased NO synthesis; however, tempol and Mn(III)TMPyP reversed the high D-glucose-reduced BH4 level. Insulin and tempol blocked the high D-glucose-increased p42/44mapk phosphorylation. Vascular dysfunction caused by high D-glucose is likely attenuated by insulin through the L-arginine/NO and O2•-/NADPH oxidase pathways. These findings are of interest for better understanding vascular dysfunction in states of foetal insulin resistance and hyperglycaemia.