Clinical and pulmonary function analysis in long-COVID revealed that long-term pulmonary dysfunction is associated with vascular inflammation pathways and metabolic syndrome.

Introduction: Long-term pulmonary dysfunction (L-TPD) is one of the most critical manifestations of long-COVID. This lung affection has been associated with disease severity during the acute phase and the presence of previous comorbidities, however, the clinical manifestations, the concomitant consequences and the molecular pathways supporting this clinical condition remain unknown. The aim of this study was to identify and characterize L-TPD in patients with long-COVID and elucidate the main pathways and long-term consequences attributed to this condition by analyzing clinical parameters and functional tests supported by machine learning and serum proteome profiling. Methods: Patients with L-TPD were classified according to the results of their computer-tomography (CT) scan and diffusing capacity of the lungs for carbon monoxide adjusted for hemoglobin (DLCOc) tests at 4 and 12-months post-infection. Results: Regarding the acute phase, our data showed that L-TPD was favored in elderly patients with hypertension or insulin resistance, supported by pathways associated with vascular inflammation and chemotaxis of phagocytes, according to computer proteomics. Then, at 4-months post-infection, clinical and functional tests revealed that L-TPD patients exhibited a restrictive lung condition, impaired aerobic capacity and reduced muscular strength. At this time point, high circulating levels of platelets and CXCL9, and an inhibited FCgamma-receptor-mediated-phagocytosis due to reduced FcγRIII (CD16) expression in CD14+ monocytes was observed in patients with L-TPD. Finally, 1-year post infection, patients with L-TPD worsened metabolic syndrome and augmented body mass index in comparison with other patient groups. Discussion: Overall, our data demonstrated that CT scan and DLCOc identified patients with L-TPD after COVID-19. This condition was associated with vascular inflammation and impair phagocytosis of virus-antibody immune complexes by reduced FcγRIII expression. In addition, we conclude that COVID-19 survivors required a personalized follow-up and adequate intervention to reduce long-term sequelae and the appearance of further metabolic diseases.

Humoral immunity against SARS-CoV-2 evoked by heterologous vaccination groups using the CoronaVac (Sinovac) and BNT162b2 (Pfizer/BioNTech) vaccines in Chile.

Introduction: Severe acute respiratory syndrome virus 2 (SARS-CoV-2) has caused over million deaths worldwide, with more than 61,000 deaths in Chile. The Chilean government has implemented a vaccination program against SARS-CoV-2, with over 17.7 million people receiving a complete vaccination scheme. The final target is 18 million individuals. The most common vaccines used in Chile are CoronaVac (Sinovac) and BNT162b2 (Pfizer-Biotech). Given the global need for vaccine boosters to combat the impact of emerging virus variants, studying the immune response to SARS-CoV-2 is crucial. In this study, we characterize the humoral immune response in inoculated volunteers from Chile who received vaccination schemes consisting of two doses of CoronaVac [CoronaVac (2x)], two doses of CoronaVac plus one dose of BNT162b2 [CoronaVac (2x) + BNT162b2 (1x)], and three doses of BNT162b2 [BNT162b2 (3x)]. Methods: We recruited 469 participants from Clínica Dávila in Santiago and the Health Center Víctor Manuel Fernández in the city of Concepción, Chile. Additionally, we included participants who had recovered from COVID-19 but were not vaccinated (RCN). We analyzed antibodies, including anti-N, anti-S1-RBD, and neutralizing antibodies against SARS-CoV-2. Results: We found that antibodies against the SARS-CoV-2 nucleoprotein were significantly higher in the CoronaVac (2x) and RCN groups compared to the CoronaVac (2x) + BNT162b2 (1x) or BNT162b2 (3x) groups. However, the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups exhibited a higher concentration of S1-RBD antibodies than the CoronaVac (2x) group and RCN group. There were no significant differences in S1-RBD antibody titers between the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups. Finally, the group immunized with BNT162b2 (3x) had higher levels of neutralizing antibodies compared to the RCN group, as well as the CoronaVac (2x) and CoronaVac (2x) + BNT162b2 (1x) groups. Discussion: These findings suggest that vaccination induces the secretion of antibodies against SARS-CoV-2, and a booster dose of BNT162b2 is necessary to generate a protective immune response. In the current state of the pandemic, these data support the Ministry of Health of the Government of Chile's decision to promote heterologous vaccination as they indicate that a significant portion of the Chilean population has neutralizing antibodies against SARS-CoV-2.

Impact of Obstructive Sleep Apnea (OSA) in COVID-19 Survivors, Symptoms Changes Between 4-Months and 1 Year After the COVID-19 Infection.

Objective: To determine the association between Obstructive Sleep Apnea (OSA) with long-term symptoms and inflammatory cytokines, exploring the changes between 4-months and 1-year after COVID-19 infection. Methods: We conducted an observational, prospective cohort study, including patients ≥18 years old with confirmed diagnosis of COVID-19 between April to July 2020. All participants underwent two clinical follow-up visits, the first at 4-months (Visit 1) and the second at 1 year, after SARS-CoV-2 infection (Visit 2). Plasma glucose, total cholesterol, HDL, and triglycerides. Regarding pulmonary function, spirometry and lung diffusion capacity tests were assessed. For mental and neurocognitive evaluation, a short-form (SF-12), Beck depression and Hospital-Anxiety depression questionnaires were conducted at both time-points, whereas the Montreal Cognitive assessment was conducted during the second follow-up. Regarding to sleep evaluation, Epworth Sleepiness Scale, Insomnia Severity index and STOP-BANG questionnaire were conducted. Additionally, a home sleep apnea test and 7-day wrist actigraphy were performed in all participants. Inflammatory cytokines were measured using an inflammatory cytokine bead array kit. p-values < 0.05 were considered statistically significant and statistical analyses were performed using R software. Results: A total of 60 patients were included in the first follow-up, from which 57 completed the second follow-up. The mean age was 46.4 years-old (SD ± 13.1) and 53.3% were male. 30% of cases reported mild COVID-19 infection, 28.3% with moderate illness, and 41.6% with severe illness. Moreover, 56.6% of them were admitted to the ICU. Regarding to metabolic values, the OSA group showed higher values of insulin resistance (IR) (27%), systolic blood pressure (SBP) 135.2 (±19.1), dyslipidemia (67.5%), total cholesterol 202.1 (±60.5), triglycerides 176.1 (±119.0) and HOMA-IR 9.0 (±18.8) in comparison with the non-OSA group. 1 year after COVID-19 infection, DLCO test remains abnormal in OSA patients (25% OSA vs. 3.6% non-OSA, p = 0.02). Finally, those participants with OSA who develop ARDS reported an adjusted OR 20.4 (95%-CI, 1.04-504) risk of neurocognitive impairment. Discussion: Among patients with previous COVID-19, OSA impact the development of incident glycemic, neurocognitive impairment, and abnormal functional pulmonary changes that persist up to 1 year since acute phase.

Undiagnosed sleep disorder breathing as a risk factor for critical COVID-19 and pulmonary consequences at the midterm follow-up.

INTRODUCTION: Patients with severe COVID-19 develops an acute respiratory distress syndrome (ARDS), requiring admission to the intensive care unit. COVID-19 also reports an increased prevalence of comorbidities, similar to patients with Sleep disorder breathing (SDB). OBJECTIVES: To evaluate the association between undiagnosed SDB and the risk of ARDS and pulmonary abnormalities in a cohort of patients' survivors of COVID-19 between 3 and 6 months after diagnosis. METHODS: Prospective cohort study of patients who developed ARDS during hospitalization due to COVID-19 compared with a control group of patients who had COVID-19 with mild to moderate symptoms. All patients were evaluated between the 12th and 24th week after SARS-CoV-2 infection. The evaluation includes persistent symptoms, lung diffusing capacity of carbon monoxide (DLCO), chest CT scan and home sleep apnea test. SDB was diagnosed by the respiratory disturbance index ≥5 ev/h. The association between SDB and ARDS, the hazards of lung impairment and the hazard ratios (HR) were analyzed. RESULTS: A total of 60 patients were included (ARDS: 34 patients, Control: 26 patients). The mean follow-up was 16 weeks (range 12-24). ARDS reported a high prevalence of SDB (79% vs. 38% in control group). A total of 35% reported DLCO impairment, and 67.6% abnormal chest CT. SDB was independently associated to ARDS, OR 6.72 (CI, 1.56-28.93), p < 0.01, and abnormal Chest CT, HR 17.2 (CI, 1.68-177.4, p = 0.01). Besides, ARDS, days in mechanical ventilation, male gender were also associated with an increased risk of abnormal chest CT. CONCLUSION: Undiagnosed SDB is prevalent and independently associated with ARDS. In addition, undiagnosed SDB increased the hazard of abnormal Chest CT in the midterm. STUDY REGISTER: ISRCTN16865246.

IFI27 transcription is an early predictor for COVID-19 outcomes, a multi-cohort observational study.

Purpose: Robust biomarkers that predict disease outcomes amongst COVID-19 patients are necessary for both patient triage and resource prioritisation. Numerous candidate biomarkers have been proposed for COVID-19. However, at present, there is no consensus on the best diagnostic approach to predict outcomes in infected patients. Moreover, it is not clear whether such tools would apply to other potentially pandemic pathogens and therefore of use as stockpile for future pandemic preparedness. Methods: We conducted a multi-cohort observational study to investigate the biology and the prognostic role of interferon alpha-inducible protein 27 (IFI27) in COVID-19 patients. Results: We show that IFI27 is expressed in the respiratory tract of COVID-19 patients and elevated IFI27 expression in the lower respiratory tract is associated with the presence of a high viral load. We further demonstrate that the systemic host response, as measured by blood IFI27 expression, is associated with COVID-19 infection. For clinical outcome prediction (e.g., respiratory failure), IFI27 expression displays a high sensitivity (0.95) and specificity (0.83), outperforming other known predictors of COVID-19 outcomes. Furthermore, IFI27 is upregulated in the blood of infected patients in response to other respiratory viruses. For example, in the pandemic H1N1/09 influenza virus infection, IFI27-like genes were highly upregulated in the blood samples of severely infected patients. Conclusion: These data suggest that prognostic biomarkers targeting the family of IFI27 genes could potentially supplement conventional diagnostic tools in future virus pandemics, independent of whether such pandemics are caused by a coronavirus, an influenza virus or another as yet-to-be discovered respiratory virus.

Validation of a Methodology for the Detection of Severe Acute Respiratory Syndrome Coronavirus 2 in Saliva by Real-Time Reverse Transcriptase-PCR.

In January 2021, the Chilean city of Concepción experienced a second wave of coronavirus 2019 (COVID-19) while in early April 2021, the entire country faced the same situation. This outbreak generated the need to modify and validate a method for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in saliva, thereby expanding the capacity and versatility of testing for COVID-19. This study was conducted in February 2021 in the Chilean city of Concepción during which time, the town was under total quarantine. The study participants were mostly symptomatic (87.4%), not hospitalized, and attended care centers because of their health status rather than being asked by the researchers. People coming to the health center in Concepción to be tested for COVID-19 (via reverse transcriptase polymerase chain reaction [RT-PCR]) from a specimen of nasopharyngeal swab (NPS) were then invited to participate in this study. A total of 131 participants agreed to sign an informed consent and to provide saliva and NPS specimens to validate a method in terms of sensitivity, specificity, and statistical analysis of the cycle threshold (Ct) values from the RT-PCR. Calculations pertaining to the 127 participants who were ultimately included in the analysis showed sensitivity and specificity at 94.34% (95% CI: 84.34-98.82%) and 98.65% (95% CI: 92.70-99.97%), respectively. The saliva specimen showed a performance comparable to NPS as demonstrated by the diagnostic parameters. This RT-PCR method from the saliva specimen is a highly sensitive and specific alternative compared to the reference methodology, which uses the NPS specimen. This modified and validated method is intended for use in the in vitro diagnosis of SARS-CoV-2, which provides health authorities in Chile and local laboratories with a real testing alternative to RT-PCR from NPS.

Analysis of clinical symptoms, radiological changes and pulmonary function data 4 months after COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) ranges from asymptomatic disease to respiratory failure and requires invasive mechanical ventilation (IMV). Data about the sequelae after infection are scarce. The study aims to describe the prevalence of symptoms, pulmonary function tests (PFTs), and radiological changes after four months of follow-up. METHODS: A prospective, cross-sectional, multicentre study was performed. Patients with different illness severities were consecutively included (mild; moderate: hospitalized without IMV; severe: hospitalized with IMV). Clinical variables, health-related quality of life (HRQoL), PFT (spirometry, diffusing capacity of the lungs for carbon monoxide (DLCO)), and (CT) scans of the chest were obtained. The association between the risk of sequelae (DLCO <80%) and altered CT was analysed using logistic regression adjusted for confounding variables. RESULTS: 60 patients (18 mild, 17 moderate, and 25 severe) were included. Fatigue was found in 11% of the mild, 47% of the moderate and 36% of the severe group. Altered DLCO (mild: 5.5%, moderate: 41%, severe: 28%, p < .05) and change in HRQoL (mild: 50%, moderate: 94%, severe: 60%), while the severe group showed a higher prevalence of altered CT (88% vs. 64%). Awake prone position (APP) and high-flow nasal cannula (HFNC) was independently associated with altered DLCO, Odds ratio (OR) 7.28 (CI, 1.10-47.81; p < .05), and altered CT, OR 9.50 (CI, 1.26-71.5; p < .05). Besides, prolonged time in IMV was associated with altered CT, OR 1.24 (CI, 1.05-1.46; p < .05). DISCUSSION: It is common to find sequelae in symptoms, radiology, and PFT. In our series, the use of APP+HFNC and days on IMV were associated with an increased risk of sequelae.

Immunomodulation of T Helper Cells by Tumor Microenvironment in Oral Cancer Is Associated With CCR8 Expression and Rapid Membrane Vitamin D Signaling Pathway.

The immune system plays a key role in the protective response against oral cancer; however, the tumor microenvironment (TME) impairs this anti-cancer response by modulating T helper (Th) responses and promoting an anti-inflammatory environment. Regulatory T cells (Tregs) and Th2 effector cells (Teff) are associated with poor prognosis in oral squamous cell carcinoma (OSCC). However, the main immunomodulatory mechanisms associated with the enrichment of these subsets in OSCC remain unknown. We characterized Th-like lineages in Tregs and Teff and evaluated immunomodulatory changes induced by the TME in OSCC. Our phenotypic data revealed a higher distribution of tumour-infiltrating CCR8+ and Th2-like Treg in OSCC compared with non-malignant samples, whereas the percentages of Th1 cells were reduced in cancer. We then analyzed the direct effect of the TME by exposing T cell subsets to cancer secretomes and observed the OSCC secretome induced CCR8 expression and reduced cytokine production from both subsets. Transcriptomic analysis showed that the co-culture with OSCC secretome induced several gene changes associated with the vitamin D (VitD) signaling pathway in T cells. In addition, proteomic analysis identified the presence of several proteins associated with prostaglandin E2 (PGE2) production by rapid membrane VitD signaling and a reduced presence of the VitD binding protein. Thus, we analyzed the effect of VitD and PGE2 and observed that VitD promotes a regulatory Th2-like response with CCR8 expression whilst PGE2 also modulated CCR8 but inhibited cytokine production in combination with VitD. Finally, we evaluated the presence of CCR8 ligand in OSCC and observed increased chemokine CCL18, which was also able to upregulate CCR8 in activated Th cells. Overall, our data showed the immunomodulatory changes induced by the TME involving CCR8 expression and regulatory Th2 phenotypes, which are associated with PGE2 mediated VitD signaling pathway and CCL18 expression in OSCC.

Chronic intermittent hypoxia in obstructive sleep apnea: a narrative review from pathophysiological pathways to a precision clinical approach.

Obstructive sleep apnea syndrome (OSAS) is a prevalent condition caused by dynamic upper airway collapse during sleep. The pathological impact and consequences are due to chronic intermittent hypoxia (CIH). Hypoxia increases the expression of several inflammatory stress markers and endothelial dysfunction. Recent studies suggest that patients with a similar AHI but with severe nocturnal hypoxia using oximetric parameters, such as the lowest saturation of oxygen during the night (min SaO2), percentage of total sleep time with oxygen saturation < 90% (T90) or the oxygen desaturation index (ODI-3%), commonly reported during the sleep study, are indicative of the increased expression of inflammatory markers due to severe nocturnal hypoxia and CIH during the night compared to subjects with moderate-severe OSAS without severe nocturnal hypoxia. The aim of this review is to describe physiological pathways involved in OSAS and their clinical consequences, focused in CIH and oximetric parameters showed in sleep study and their potential utility as inflammatory markers.

Plasma from Patients with Rheumatoid Arthritis Reduces Nitric Oxide Synthesis and Induces Reactive Oxygen Species in A Cell-Based Biosensor.

Rheumatoid arthritis (RA) has been associated with a higher risk of developing cardiovascular (CV) diseases. It has been proposed that systemic inflammation plays a key role in premature atherosclerosis development, and is therefore crucial to determine whether systemic components from RA patients promotes endothelial cell-oxidative stress by affecting reactive oxygen species (ROS) and nitric-oxide (NO) production. The aim of this study was to evaluate whether plasma from RA patients impair NO synthesis and ROS production by using the cell-line ECV-304 as a biosensor. NO synthesis and ROS production were measured in cells incubated with plasma from 73 RA patients and 52 healthy volunteers by fluorimetry. In addition, traditional CV risk factors, inflammatory molecules and disease activity parameters were measured. Cells incubated with plasma from RA patients exhibited reduced NO synthesis and increased ROS production compared to healthy volunteers. Furthermore, the imbalance between NO synthesis and ROS generation in RA patients was not associated with traditional CV risk factors. Our data suggest that ECV-304 cells can be used as a biosensor of systemic inflammation-induced endothelial cell-oxidative stress. We propose that both NO and ROS production are potential biomarkers aimed at improving the current assessment of CV risk in RA.

Apolipoprotein A-I enhances proliferation of human endothelial progenitor cells and promotes angiogenesis through the cell surface ATP synthase.

BACKGROUND: Human endothelial progenitor cells (hEPC) correspond to a subtype of stem cells which, in the presence of angiogenic stimuli, can be mobilized from bone marrow to circulation and then recruited to the damaged endothelium, where they differentiate into mature endothelial cells. High-density lipoproteins (HDL) increase the level and functionality (proliferation, migration, differentiation, angiogenesis capacity) of circulating hEPC; however, the contribution of receptors for HDL and/or apolipoprotein A-I (apoA-I), the main HDL apolipoprotein, in these effects is still unclear. On mature endothelial cells, the cell surface F1-ATP synthase has been previously characterized as a high affinity receptor of apoA-I, whereas the scavenger receptor SR-BI mainly binds with fully lipidated HDL and displays a poor affinity for lipid-free apoA-I. Furthermore, it was shown that apoA-I binding to surface ATP synthase on mature endothelial cells promotes cell proliferation, whereas inhibits apoptosis. In this work, we aimed to determine the effect of apoA-I in the proliferation and the angiogenic capacity of early hEPC, and the contribution of the cell surface ATP synthase in these events. RESULTS: We first evidenced that early hEPC express the ATP synthase at the surface of nonpermeabilized cells, where it is not colocalized with MitoTracker, a mitochondria marker. ApoA-I (50 µg/mL) increases hEPC proliferation (+14.5%, p<0.001) and potentiates the effect of hEPC on a cellular model of angiogenesis, with an increase of +31% (p<0.01) in branch point counting and in tubule length. These effects of apoA-I were totally reversed in the presence of ATP synthase inhibitors, such as IF1 or oligomycin, whereas the inhibition of the HDL receptor, SR-BI, partially inhibits these events. CONCLUSIONS: These results provide the first evidence that surface ATP synthase is expressed on early hEPC, where it mediates apoA-I effects in hEPC proliferation and in angiogenesis. This knowledge could be helpful for future investigations focused on the regulation of the number and functionality of these cells and in the development of new therapies for the treatment of diseases, such as cardiovascular disease.

Endothelium trans differentiated from Wharton's jelly mesenchymal cells promote tissue regeneration: potential role of soluble pro-angiogenic factors.

BACKGROUND: Mesenchymal stem cells have a high capacity for trans-differentiation toward many adult cell types, including endothelial cells. Feto-placental tissue, such as Wharton's jelly is a potential source of mesenchymal stem cells with low immunogenic capacity; make them an excellent source of progenitor cells with a potential use for tissue repair. We evaluated whether administration of endothelial cells derived from mesenchymal stem cells isolated from Wharton's jelly (hWMSCs) can accelerate tissue repair in vivo. METHODS: Mesenchymal stem cells were isolated from human Wharton's jelly by digestion with collagenase type I. Endothelial trans-differentiation was induced for 14 (hWMSC-End14d) and 30 (hWMSC-End30d) days. Cell phenotyping was performed using mesenchymal (CD90, CD73, CD105) and endothelial (Tie-2, KDR, eNOS, ICAM-1) markers. Endothelial trans-differentiation was demonstrated by the expression of endothelial markers and their ability to synthesize nitric oxide (NO). RESULTS: hWMSCs can be differentiated into adipocytes, osteocytes, chondrocytes and endothelial cells. Moreover, these cells show high expression of CD73, CD90 and CD105 but low expression of endothelial markers prior to differentiation. hWMSCs-End express high levels of endothelial markers at 14 and 30 days of culture, and also they can synthesize NO. Injection of hWMSC-End30d in a mouse model of skin injury significantly accelerated wound healing compared with animals injected with undifferentiated hWMSC or injected with vehicle alone. These effects were also observed in animals that received conditioned media from hWMSC-End30d cultures. CONCLUSION: These results demonstrate that mesenchymal stem cells isolated from Wharton's jelly can be cultured in vitro and trans-differentiated into endothelial cells. Differentiated hWMSC-End may promote neovascularization and tissue repair in vivo through the secretion of soluble pro-angiogenic factors.

Lectin-like oxidized LDL receptor-1 is an enhancer of tumor angiogenesis in human prostate cancer cells.

Altered expression and function of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has been associated with several diseases such as endothelial dysfunction, atherosclerosis and obesity. In these pathologies, oxLDL/LOX-1 activates signaling pathways that promote cell proliferation, cell motility and angiogenesis. Recent studies have indicated that olr1 mRNA is over-expressed in stage III and IV of human prostatic adenocarcinomas. However, the function of LOX-1 in prostate cancer angiogenesis remains to be determined. Our aim was to analyze the contribution of oxLDL and LOX-1 to tumor angiogenesis using C4-2 prostate cancer cells. We analyzed the expression of pro-angiogenic molecules and angiogenesis on prostate cancer tumor xenografts, using prostate cancer cell models with overexpression or knockdown of LOX-1 receptor. Our results demonstrate that the activation of LOX-1 using oxLDL increases cell proliferation, and the expression of the pro-angiogenic molecules VEGF, MMP-2, and MMP-9 in a dose-dependent manner. Noticeably, these effects were prevented in the C4-2 prostate cancer model when LOX-1 expression was knocked down. The angiogenic effect of LOX-1 activated with oxLDL was further demonstrated using the aortic ring assay and the xenograft model of tumor growth on chorioallantoic membrane of chicken embryos. Consequently, we propose that LOX-1 activation by oxLDL is an important event that enhances tumor angiogenesis in human prostate cancer cells.

Role of lectin-like oxidized low density lipoprotein-1 in fetoplacental vascular dysfunction in preeclampsia.

The bioavailability of nitric oxide (NO) represents a key marker in vascular health. A decrease in NO induces a pathological condition denominated endothelial dysfunction, syndrome observed in different pathologies, such as obesity, diabetes, kidney disease, cardiovascular disease, and preeclampsia (PE). PE is one of the major risks for maternal death and fetal loss. Recent studies suggest that the placenta of pregnant women with PE express high levels of lectin-like oxidized LDL receptor-1 (LOX-1), which induces endothelial dysfunction by increasing reactive oxygen species (ROS) and decreasing intracellular NO. Besides LOX-1 activation induces changes in migration and apoptosis of syncytiotrophoblast cells. However, the role of this receptor in placental tissue is still unknown. In this review we will describes the physiological roles of LOX-1 in normal placenta development and the potential involvement of this receptor in the pathophysiology of PE.

L-arginine transport and nitric oxide synthesis in human endothelial progenitor cells.

Nitric oxide (NO) is an endogenous vasodilator molecule synthetized from L-arginine by a family of nitric oxide synthases. In differentiated human endothelial cells, it is well known that L-arginine uptake via cationic amino acid transporters (y(+)/CAT) or system y(+)L is required for the NO synthesis via endothelial nitric oxide synthase, but there are no reports in human endothelial progenitor cell (hEPC). Therefore, we isolated hEPCs from peripheral blood of healthy donors and cultured them for either 3 (hEPC-3d) or 14 days (hEPC-14d) to characterize the L-arginine transport and NO synthesis in those cells. L-arginine transport and NO synthesis were analyzed in the presence or absence of N-ethylmaleimide or L-nitroarginine methyl ester, as inhibitors of y(+)/CAT system and nitric oxide synthases, respectively. The results showed that L-arginine uptake is higher in hEPC-14d than in hEPC-3d. Kinetic parameters for L-arginine transport showed the existence of at least 2 transporter systems in hEPC: a high affinity transporter system (K(m)= 4.8 ± 1.1 µM for hEPC-3d and 6.1 ± 2.4 µM for hEPC-14d) and a medium affinity transporter system (K(m) = 85.1 ± 4.0 µM for hEPC-3d and 95.1 ± 8 µM for hEPC-14d). Accordingly, hEPC expressed mRNA and protein for CAT-1 (ie, system y(+)) and mRNA for 2 subunits of y(+)L system, yLAT1, and 4F2hc. Higher L-citruline production and NO bioavailability (4-fold), and endothelial nitric oxide synthase expression (both mRNA and protein) were observed in hEPC-14d compared with hEPC-3d. Finally, the high L-citruline formation observed in hEPC-14d was blocked by N-ethylmaleimide. In conclusion, this study allowed to identity a functional L-arginine/NO pathway in two hEPC differentiation stages, which improves the understanding of the physiology of these precursor cells.

Adenosine A2A and A3 receptors are involved in the human endothelial progenitor cells migration.

Human endothelial progenitor cells (hEPC) are recruited to sites of neovascularization where they differentiate into endothelial cells. The signals/factors responsible for hEPC migration and adhesion to sites of injury are not well understood. Elevated levels of adenosine are known to increase mature endothelial cell migration in response to tissue injury. However, the understanding of the role of adenosine in the physiology of hEPC is very limited. Using quantitative polymerase chain reaction and western blot analyses, we detected the expression of the adenosine receptors A2A, A2B, and A3 in hEPC. Stimulation of adenosine receptors using adenosine or the nonselective agonist adenosine-5'-N-ethylcarboxamide (NECA) increased hEPC migration in 1.4-fold and 2.1-fold (P < 0.01), respectively. Stimulation of hEPC using the A2A-specific agonist CGS-21680 resembled the effect observed in migration when using adenosine or NECA. Consequently, NECA and CGS-21680-stimulated migration of hEPC were reverted using the A2A receptor antagonist ZM-241385. NECA-stimulated migration was inhibited in dose-dependent manner using MRS-1523 (Ki of 147 ± 0.016 nM), MRS-1754 (Ki of 1900 ± 0.02 nM), or ZM-241385 (Ki of 0.2 ± 0.01 nM). In conclusion, adenosine stimulates hEPC migration by activating A2A and A3 but not A2B receptors and provides evidence to support a role of adenosine in modulating angiogenic capacity of hEPC.

Diferencias en la aterosclerosis coronaria entre hombres y mujeres con Diabetes Mellitus tipo 2 evaluados con el Score de Gensini / Differences in coronary atherosclerosis assessed with the Gensini score between men and women with type 2 Diabetes

Antecedentes y Objetivos: Las mujeres diabéticas tienen mayor morbi-mortalidad asociada a eventos coronarios isquémicos que los hombres. Este estudio describe la extensión, magnitud y severidad de la ateros-clerosis coronaria entre hombres y mujeres con diabetes mellitus tipo 2. Métodos: Estudio de tipo descriptivo que incluyó a 162 pacientes diabéticos consecutivos con sospecha de aterosclerosis coronaria y estudiados con coronariogra-fía. La magnitud de la aterosclerosis fue cuantificada utilizando el Score de Gensini. Resultados: La edad promedio fue 64.8 años. Noventa y cuatro eran mujeres (58.0 por ciento). El tiempo de evolución de la diabetes fue mayor para mujeres que para hombres (152.1 +/- 90.0 vs 120.2 +/- 99.4 meses) respectivamente (p<0.05). Las mujeres tuvieron un índice de masa corporal (30.5 +/- 5.1), superior al de los hombres (28.5 +/- 5.2) (p<0.05). La aterosclerosis coronaria significativa estuvo presente en el 61.7 por ciento de toda la población diabética, siendo en hombres de 76.5 por ciento versus 51.5 por ciento en mujeres (odds ratio: 1.5). El número de placas ateroscle-róticas fue 195 en 68 hombres (2,86 placa/paciente) y de 168 en 94 mujeres (1,78 placa/paciente) (p<0.0043). La presencia de aterosclerosis significativa en 1, 2 y 3 vasos se observó en el 7.4 por ciento; 17.6 por ciento y 51.5 por ciento de los hombres, respectivamente, versus el 12.8 por ciento; 10.6 por ciento y 27.7 por ciento en las mujeres, (p<0.0002). La magnitud de la enfermedad coronaria medida con el Score de Gensini fue 69.4 +/- 66.7 en hombres versus 35.6 +/- 47.3 en mujeres (p<0.005). Conclusión: En este estudio observamos que hombres diabéticos tienen mayor extensión, magnitud y severidad de aterosclerosis coronaria que las mujeres diabéticas.

Diabetic women have higher morbidity and mortality associated with ischemic coronary events than diabetic men, but the extension of coronary artery disease in both groups is less well established. Aim: to compare the extension, magnitude and severity of coronary atherosclerosis between men and women with type 2 diabetes mellitus. Method: 162 consecutive diabetic patients with suspected coronary atherosclerosis studied by coronary angiography were included. The magnitude of atherosclerosis was quantified using the Gensini Score. Results: The average age was 64.8 years. Ninety-four patients were women (58.0 percent). Diabetes was present for 152 +/- 90.0 months for women and 120 +/- 99.4 months for men (p <0.05). Women had a higher body mass index (30.5 +/- 5.1) than men (28.5 +/- 5.2, p<0.05). The presence of significant coronary atherosclerosis in the entire diabetic population was of 61.7 percent: 76.5 percent in men and 51.5 percent in women (OR 1.5). The mean number of atherosclerotic plaques was 195 in 68 men (2.86 plaques/patient) and 168 in 94 women (1.78 plaques/patient, p=0.0043). Significant atherosclerosis in 1, 2 and 3 vessels was observed in 7.4 per cent, 17.6 percent and 51.5 percent of men, respectively, versus 12.8 percent, 10.6 percent and 27.7 percent in women (p<0.0002). The magnitude of coronary disease measured by Gensini Score was 69.4 + 66.7 in men versus 35.6 +/- 47.3 in women (p<0.005). Conclusion: Men with diabetes have greater extension, magnitude and severity of coronary atherosclerosis than diabetic women.

Fetal endothelium dysfunction is associated with circulating maternal levels of sE-selectin, sVCAM1, and sFlt-1 during pre-eclampsia.

OBJECTIVES: To evaluate the association between endothelial activation markers in the maternal circulation with nitric oxide (NO) synthesis in human umbilical endothelial cells. STUDY DESIGN: This is a case-control study of normal and pre-eclamptic pregnancies. The levels of sE-selectin, soluble vascular cell adhesion molecule 1 (sVCAM-1), and soluble fms-like tyrosine kinase 1 (sFlt-1) were measured by enzyme-linked immunosorbent assay, and histamine-induced NO synthesis was detected by fluorometric examination of the human umbilical vein endothelial cells (HUVECs) isolated from normal and pathological pregnancies. RESULTS: Mothers with severe pre-eclamptic pregnancies have premature and smaller babies than mothers with normal pregnancies (P < 0.05); they also have high maternal plasma levels of sVCAM-1 (∼2-fold), sFlt-1 (∼2.5-fold), and lower (∼70%) histamine-stimulated NO synthesis in HUVECs. A positive relationship between systolic blood pressure (SBP) and plasma levels of sE-selectin, sVCAM-1, and sFlt-1 was demonstrated. Moreover, levels of sE-selectin, sVCAM-1, and sFlt-1 were negatively associated with newborn weight (NBW), gestational age at delivery, and NO synthesis. Women with high E-selectin (>63 ng/ml), VCAM-1 (>752 ng/ml), and sFlt-1 (>15204 pg/ml) showed high risk (∼2-fold) for preterm delivery and very preterm delivery, or fetal weight <1500 g (∼1.5-fold) compared with women with low levels. CONCLUSIONS: High circulating levels of maternal endothelial dysfunction markers present in pre-eclampsia are associated with decreased NO synthesis in fetal endothelium.

High LDL levels are associated with increased lipoprotein-associated phospholipase A(2) activity on nitric oxide synthesis and reactive oxygen species formation in human endothelial cells.

OBJECTIVE: To evaluate in vitro the effects of serum and LDL fractions isolated from hypercholesterolemic patients on nitric oxide (NO) synthesis and reactive oxygen species (ROS) production by human umbilical vein endothelial cells (HUVECs). DESIGN AND METHODS: Serum and LDL isolated from subjects with high (n=18) and normal (n=21) LDL-cholesterol levels were analyzed on NO synthesis and ROS production in vitro models of HUVECs. LDL was furthers characterized in their chemical composition and activities of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), cholesteryl ester transfer protein (CETP) and paraoxonase. RESULTS: NO bioavailability was significantly lower and ROS production higher in HUVECs incubated with serum samples from patients with high LDL-cholesterol levels in comparison to control subjects. Moreover, hypercholesterolemic patients presented higher CETP and Lp-PLA(2) activities than control subjects. LDL fractions isolated from patients and controls were not different in their chemical composition, Lp-PLA(2) activity, and their capacity to reduce NO synthesis and increase ROS production. CONCLUSION: Alterations of serum from hypercholesterolemic patients could be due to the increment in LDL concentration, main Lp-PLA(2) carrier, and not to LDL composition or intrinsic Lp-PLA(2) activity.

Hyperglycaemia inhibits thymidine incorporation and cell growth via protein kinase C, mitogen-activated protein kinases and nitric oxide in human umbilical vein endothelium.

An elevated extracellular concentration of D-glucose (i.e. hyperglycaemia) inhibits cell proliferation and incorporation of the endogenous nucleoside thymidine into DNA in human umbilical vein endothelial cells (HUVECs). Cells in their log-phase of growth (3.7 +/- 0.3 days, n = 27) incubated for 30 min with 25 mM D-glucose, but not with equimolar concentrations of L-glucose or D-mannitol, exhibited reduced [3H]thymidine incorporation and cell growth rate, with no change in cell viability (> 98 %), total DNA, protein content or cell volume. Incubation with D-glucose activated protein kinase C (PKC), endothelial NO synthase (eNOS), p42 and p44 mitogen-activated protein kinases (p42/44(mapk)), but inhibited superoxide dismutase (SOD). Incubation with D-glucose also increased cGMP and cAMP levels. The effect of D-glucose was blocked by the PKC inhibitor calphostin C, the MAP kinase kinase 1/2 (MEK1/2) inhibitor PD-98059, the eNOS inhibitor L-NAME, the protein kinase G (PKG) inhibitor KT-5823 and the protein kinase A (PKA) inhibitor KT-5720. In the presence of 5 mM D-glucose, [3H]thymidine incorporation and cell growth were reduced by the PKC activator phorbol 12-myristate 13-acetate (PMA), the NO donor S-nitroso-N-acetyl-L,D-penicillamine (SNAP), dibutyryl cGMP, dibutyryl cAMP and the Ca2+ ionophore A-23187. The effect of A-23187 was blocked by calphostin C and PD-98059. D-Glucose-dependent inhibition of thymidine incorporation and cell proliferation is associated with increased PKC, eNOS, and MEK1/2, but decreased SOD activity, and higher intracellular levels of cGMP, cAMP and Ca2+ in HUVECs. These are cellular mechanisms which may reduce endothelial cell growth in pathological conditions such as in diabetes mellitus or hyperglycaemia.