Endothelial nitric oxide synthase levels and their response to exercise in patients with slow coronary flow

Plasma eNOS Concentration in Healthy Pregnancy and in Hypertensive Disorders of Pregnancy: Evidence of Reduced Concentrations in Pre-Eclampsia from Two Independent Studies

Hypertensive disorders of pregnancy (HDP), comprising gestational hypertension (GH) and pre-eclampsia (PE), are leading causes of maternal and perinatal morbidity and mortality. Both GH and PE are characterized by new-onset hypertension, but PE additionally includes proteinuria and/or end-organ damage. Impaired nitric oxide (NO) bioavailability may lead to endothelial dysfunction in GH and PE, and the primary source of vascular NO is endothelial NO synthase (eNOS). However, no previous study has investigated plasma eNOS concentrations in patients with GH and PE. In this study, we compared plasma eNOS concentrations in healthy pregnancies and HDP in two independent cohorts. The primary study included 417 subjects, with 43 non-pregnant (NP) and 156 healthy pregnant (HP) women and 122 patients with GH and 96 with PE. The replication study included 85 pregnant women (41 healthy and 44 pre-eclamptic). Plasma concentrations of eNOS were measured using a commercial ELISA kit provided by R&D Systems, and plasma nitrite concentrations were assessed using two ozone-based chemiluminescence assays. Correlations between plasma eNOS concentrations and plasma nitrite concentrations, as well as clinical and biochemical parameters, were evaluated by either Spearman's or Pearson's tests. In the primary study, NP women and HDP had significantly lower plasma eNOS concentrations compared to HP; concentrations were even lower in PE compared to GH. Plasma eNOS concentrations were reduced but not significant in early-onset PE, PE with severe features, preterm birth, and intrauterine growth restriction. No correlation was observed between plasma eNOS and nitrite levels. In HDP, there was a significant positive correlation between levels of eNOS and hemoglobin (r = 0.1496, p = 0.0336) as well as newborn weight (r = 0.1487, p = 0.0316). Conversely, a negative correlation between eNOS levels and proteinuria was observed (r = -0.2167, p = 0.0179). The replication study confirmed significantly reduced plasma concentrations of eNOS in PE compared to HP. Our findings provide evidence of reduced plasma eNOS concentrations in HDP; they were particularly lower in PE compared to GH and HP in two independent studies.

Endothelial nitric oxide synthase Asp298Glu (894G/T) gene polymorphism as a possible risk factor for the coronary slow flow phenomenon among Iranians

Background

Mounting evidence indicates an association between endothelial dysfunction and the coronary slow flow phenomenon (CSFP). In the present study, we aimed to evaluate the possible role of endothelial nitric oxide synthase (eNOS) 894G/T and interleukin-1β (IL-1β) 315C/T polymorphisms as possible risk factors for CSFP.

Methods

This prospective study enrolled patients with CSFP and individuals with normal coronary arteries. Genotypes were assessed using regular polymerase chain reaction and direct Sanger-sequencing techniques.

Results

The study population consisted of 267 individuals: 180 patients with CSFP (49 women [27.2%]) at a median age of 55 (48–62) years and 87 controls with normal coronary arteries (56 women [64.4%]) at a median age of 47 (41–58) years. The allelic distribution of eNOS 894G/T was significantly associated with CSFP (odds ratio [OR], 1.58; 95% confidence interval (CI), 1.04–2.42; P = 0.03). This polymorphism increased the risk of CSFP under the dominant model (OR 1.73; 95% CI I.02–2.95; P = 0.04). However, the allelic frequencies (1.05; 95% CI 0.68–1.59; P = 0.83) and genotypic frequencies (0.88; 95% CI 0.52–1.49; P = 0.63) of the IL-1β 315C/T polymorphism were not associated with the incidence of CSFP in the Iranian population.

Conclusions

The CSFP and control groups were statistically different regarding the eNOS 894G/T polymorphism. Our findings also demonstrated that the IL-1β 315C/T polymorphism was not a risk factor for CSFP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02736-0.

Assessment of the accuracy of testicular dysfunction detection in male donkey (Equus asinus) with the aid of colour-spectral Doppler in relation to plasma testosterone and serum nitric oxide levels

This study aimed to determine the usefulness of colour and pulsed Doppler modes for the accurate diagnosis of donkeys suffering from subfertility to determine whether testicular vascularity assessment could be an indicator for sperm functionality. The study sample was composed of 10 male donkeys with normospermia (control group) and 10 donkeys with hypospermia. Animals underwent scrotal circumference measurement, testicular Doppler examination, seminal evaluation, blood sampling and hormonal assay. Semen volume and concentration were significantly (p ≤ .05) lower in the subfertile group (30.25 ± 1.22 ml and 89.44 ± 2.55 × 10⁶ /ml) as compared with the control group (82.76 ± 1.65 ml and 452.78 ± 1.25 × 10⁶ /ml), and total sperm/ejaculation was significantly (p ≤ .05) higher in the normal donkeys (28.30 ± 2.32 × 10⁹ /total ejaculated) as compared with the subfertile group. Intratesticular coloured area showed a marked decline in the hypospermic males. There was no significant difference between the two groups in testosterone level, although the normal group showed an increase in nitric oxide metabolites. Both Doppler indices of the three branches of the testicular artery were elevated significantly (p ≤ .05) in abnormal donkeys, whereas Doppler peak systolic and end-diastolic velocities were increased in the normal group. Male donkeys with subfertility demonstrated lower arterial vascularity parameters in the form of intratesticular coloured area and blood flow rate; therefore, the most optimal parameters for differentiating subfertile hypospermic from normospermic donkeys were found to be the two Doppler indices, velocities parameters, testicular blood flow rate and nitric oxide levels.

Cardiovascular Protection Variables Based on Exercise Intensity in Stable Coronary Heart Disease Patients After Coronary Stenting: A Comparative Study

Purpose

Our study aimed at determining and comparing the mechanism of cardiovascular protection variables in moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) in patients with stable coronary heart disease (CHD) after coronary stenting.

Participants and Methods

This experimental study used the same subject and cross-over design, involving eleven stable CHD patients after coronary stenting. These were randomly divided into two groups; MICT for 29 minutes at 50–60% heart rate reserve and HIIT with 4x4 minute intervals at 60–80% heart rate reserve, each followed by three minutes of active recovery at 40–50% heart rate reserve. These were conducted three times a week for two weeks. The participants’ levels of adrenaline, noradrenaline, endothelial nitric oxide synthase (eNOS), extracellular superoxide dismutase (EC-SOD) activity assayed, and flow-mediated dilatation (FMD) were examined before and after treatments were completed.

Results

The HIIT significantly increased the levels of noradrenaline and eNOS compared with MICT (p<0.05). Also, HIIT was better in maintaining EC-SOD activity and FMD compared with MICT (p<0.05). Through the noradrenalin pathway, HIIT had a direct and significant effect on eNOS and FMD (p<0.05) but MICT, through the noradrenaline pathways, had a direct and significant effect on eNOS (p<0.05), and through the EC-SOD activity pathways had a direct and significant effect on FMD (p<0.05). MICT reduced EC-SOD activity and also decreased the FMD value.

Conclusion

HIIT is superior to MICT in increasing cardiovascular protection by increasing the concentrations of noradrenalin and eNOS, maintaining EC-SOD activity, and FMD in stable CHD patients after coronary stenting.

Increased plasma lipoprotein-associated phospholipase A2 levels are associated with coronary slow flow

OBJECTIVE

Coronary slow flow (CSF) is characterized by delayed opacification of distal epicardial coronary arteries without significant coronary stenosis. In addition, The changes of lipoprotein-associated phospholipase A2 (Lp-PLA₂) as a significant predictive factor for CSF remain controversial. The study aims to investigate the association between plasma Lp-PLA₂ and CSF.

METHODS

In this retrospective study, 170 consecutive patients who underwent coronary angiography were enrolled in Beijing Anzhen Hospital from January 2017 to September 2019, and were divided into CSF group and normal control groups. According to coronary blood flow rate measured by the thrombolysis in myocardial infarction frame count (TFC) method, CSF was defined as TFC > 27. Serum Lp-PLA₂ levels were measured in an enzyme-linked immunosorbent assay.

RESULTS

Lp-PLA₂ levels were higher in the CSF group than in the control group (288.6 ± 50.3 versus 141.9 ± 49.7, P < 0.001) and were significantly correlated with the mean coronary artery thrombolysis in myocardial infarction (TIMI) frame count (r = 0.790, P<0.001). Logistic regression analysis showed that high Lp-PLA₂ was independently associated with CSF after adjustment for conventional risk factors (OR = 1.040, CI = 1.022-1.059, P<0.001). Male sex (OR = 2.192, CI = 1.161-4.140, P = 0.016) and hypertension (OR = 1.965, CI = 1.034-3.736, P = 0.039) were also CSF risk factors. Receiver-operating characteristic curve (ROC) analysis showed that Lp-PLA₂ levels can predict CSF severity; the predictive power was higher than the other risk factors.

CONCLUSION

Our study demonstrated that patients with CSF had higher circulating levels of Lp-PLA₂ than normal controls. After adjustment for potential confounders, increased Lp-PLA₂ was independently associated with presence of CSF.

Circadian fluctuations of endothelial nitric oxide synthase activity in females with rheumatoid arthritis: a pilot study

Rheumatoid arthritis (RA) is a disease associated with circadian disorders of steroid hormones or cytokine secretion which induce inflammatory, destructive and proliferative processes in the synovial joints. Angiogenesis plays an important role in RA, but circadian rhythms of the angiogenic mediator production, especially endothelial nitric oxide synthase (NOS3), are still unclear. NOS3 takes part in regulation of endothelial functions, inflammation, and bone remodeling process. Studying circadian rhythms of NOS3 production in RA patients will make an improvement in understanding the angiogenic-inflammatory pathways relevant to rheumatic diseases. The aim of the study was to test the hypothesis of a diurnal variation in circulating levels of NOS3 in RA patients. A cross-sectional monocentric pilot study of circadian variability of endothelial nitric oxide synthase in a Ukrainian population was conducted between March and July 2017. We examined 36 RA patients (100% women) and 34 age-matched healthy women without joint diseases and autoimmune diseases (control). Blood samples were collected four times per day (at 08:00; 14:00; 20:00 and 02:00) for two consecutive days. Serum NOS3 concentration was measured by ELISA (Cloud-Clone Corp kit). The study was conducted in compliance with bioethical standards. The SPSS22 software package was used for statistical processing of the results. A diurnal variation in circulating levels of NOS3 in healthy women was established, with peak values appearing in the evening and acrophase at 20:00, and low values in the morning, with batiphase at 08:00. In patients with RA serum, NOS3 levels were substantially decreased throughout the day compared to the control. In RA patients, a diurnal variation in circulating levels of NOS3 was also established. However, the variability of NOS3 production was higher in RA patients than in the control group. For example, in RA patients the difference between morning/evening values of NOS3 was 1.3 times higher (p < 0.05) than in the control. Negative correlations were found between the morning NOS3 levels and RA activity markers such as DAS28 and the number of tender and swollen joints. The diurnal variation in circulating levels of NOS3 in women with RA as well as in healthy women was found. However, in RA patients, a decrease in NOS3 production was observed, especially in the morning, which was associated with an increase in the disease activity. Thus, the circadian rhythm of circulating NOS3 can be opposite to the circadian rhythm of secretion of main inflammatory regulators in RA.

Association between impaired cutaneous microvascular endothelial function and lectin-like oxidized low-density lipoprotein receptor-1 in patients with coronary slow flow

OBJECTIVE

Although increasing studies indicate coronary slow flow (CSF) is a systemic microvascular disorder, whether there is impaired cutaneous microvascular endothelial function in CSF patients remains unclear. This study was designed to test the hypothesis that the cutaneous microvascular endothelial function of CSF patients is impaired and correlates with lectin-like oxidized low-density lipoprotein receptor-1(LOX-1).

METHODS

39 patients with CSF and 45 controls with normal coronary flow were enrolled. Velocity of coronary flow was quantitatively identified by thrombolysis in myocardial infarction frame count (TFC) method. LSCI system was used to assess subjects' cutaneous blood flow at rest and during PORH. Serum soluble LOX-1(sLOX-1) level was measured in all study subjects.

RESULTS

PORH-induced vasodilation was significantly reduced in CSF group in comparison with control group (0.26 ± 0.10 vs 0.35 ± 0.07 APU/mmHg, P < 0.001) and negatively correlated with the mean TFC for three coronary arteries (r = -0.385, P = 0.016). Serum sLOX-1 level in CSF group was significantly increased (582.93 ± 74.89 vs 483.64 ± 51.38 pg/ml, P < 0.001) and positively correlated with mean TFC(r = 0.467, P = 0.003).PORH response amplitudes had a significantly negative relationship with serum sLOX-1 level in CSF patients (r = -0.588, P < 0.001).

CONCLUSION

These data suggest that cutaneous microvascular endothelial function is impaired in patients with CSF, which is closely associated with increased LOX-1 expression.

Serum YKL-40 is increased in patients with slow coronary flow

OBJECTIVES

There is accumulating evidence that inflammation plays a major role in the development of the slow coronary flow (SCF) phenomenon. YKL-40 has been suggested to be a potential biomarker of inflammation. In this study, we aimed to study YKL-40 as it relates to SCF.

MATERIALS AND METHODS

Patients who underwent coronary angiography before and had angiographically normal coronary arteries of varying coronary flow rates without any atherosclerotic lesion were enrolled in this study. Patients who had thrombolysis in myocardial infarction frame counts (TFC) above the normal cutoffs were considered to have SCF and those within normal limits were considered to have normal coronary flow (NCF). The YKL-40 levels and biochemical profiles of all patients were studied and analyzed.

RESULTS

There were 41 patients in the SCF group and 209 patients in the NCF group. Compared with the NCF patients, SCF patients had higher serum high-sensitivity C-reactive protein (hs-CRP) (P=0.0003) and YKL-40 (P=0.0007) levels. A positive correlation was detected between the YKL-40 levels and hs-CRP (r=0.7021, P<0.001), and the mean TFC (r=0.4038, P=0.0088) in SCF patients.

CONCLUSION

Our study showed that YKL-40 levels are higher and correlated positively with TFC and hs-CRP in SCF patients. This finding suggests that YKL-40 may be a useful marker and predictor for SCF.

Interleukin-10 promotor -592A/C polymorphism is associated with slow coronary flow in Han Chinese

An accumulating body of evidence suggests that slow coronary flow (SCF) phenomenon seems to be an early-form of atherosclerosis and low-grade inflammation plays a major role in the atherosclerotic vascular processes. Interleukin (IL)-10 is a multifunctional cytokine involved in both innate and adaptive immune response. The aim of the present study is to investigate the association of IL-10 gene -592A/C polymorphism with SCF in Han Chinese. 250 patients who underwent coronary angiography and had angiographically normal coronary arteries of varying coronary flow rates without any atherosclerotic lesion were enrolled in this study. Patients who had thrombolysis in myocardial infarction frame counts (TFC) above the normal cutoffs were considered to have SCF and those within normal limits were considered to have normal coronary flow (NCF). The PCR-based restriction fragment length polymorphism (PCR-RFLP) technique was used to assess the genotypes frequencies. The distribution of the IL-10 -592A/C genotypes (AA, AC, and CC) was 46.34%, 41.46%, and 12.20% in the NCF group, and 66.51%, 28.71%, and 4.78% in SCF subjects, respectively (P = 0.0280). The frequency of the A allele in the SCF group was significantly higher than that in the NCF group (80.86% vs. 67.07%, P = 0.0054). Compared with the CC genotype, the AA genotype had increased risk of SCF in both unadjusted and adjusted analyses. In SCF patients, the average serum IL-10 levels in AA genotype were statistically lower than in AC + CC genotype (P = 0.0000). These findings suggest that IL-10 -592A/C polymorphism is associated with SCF and the A allele has increased risk for SCF in Han Chinese.

Comparative angioprotective effects of magnesium compounds

Magnesium (Mg) deficiency is implicated in the development of numerous disorders of the cardiovascular system. Moreover, the data regarding the efficacy of different magnesium compounds in the correction of impaired functions due to low magnesium intake are often fragmentary and inconsistent. The aim of this study was to compare the effects of the most bioavailable Mg compounds (Mg l-aspartate, Mg N-acetyltaurate, Mg chloride, Mg sulphate and Mg oxybutyrate) on systemic inflammation and endothelial dysfunction in rats fed a low Mg diet for 74 days. A low Mg diet decreased the Mg concentration in the plasma and erythrocytes, which was accompanied by a reduced concentration of eNOs and increased levels of endothelin-1 level in the serum and impaired endothelium-dependent vasodilatation. These effects increased the concentration of proinflammatory molecules, such as VCAM-1, TNF-α, IL-6 and CRP, indicating the development of systemic inflammation and endothelial dysfunction. The increased total NO level, which estimated from the sum of the nitrate and nitrite concentrations in the serum, may also be considered to be a proinflammatory marker. Two weeks of Mg supplementation partially or fully normalised the ability of the vascular wall to effect adequate endothelium-dependent vasodilatation and reversed the levels of most endothelial dysfunction and inflammatory markers (except CRP) to the mean values of the control group. Mg sulphate had the smallest effect on the endothelin-1, TNF-α and VCAM-1 levels. Mg N-acetyltaurate was significantly more effective in restoring the level of eNOS compared to all other studied compounds, except for Mg oxybutyrate. Taken together, the present findings demonstrate that all Mg compounds equally alleviate endothelial dysfunction and inflammation caused by Mg deficiency. Mg sulphate tended to be the least effective compound.