Unveiling the Role of Endothelial Dysfunction: A Possible Key to Enhancing Catheter Ablation Success in Atrial Fibrillation

Atrial fibrillation, a prevalent type of arrhythmia, is increasingly contributing to the economic burden on healthcare systems. The development of innovative treatments, notably catheter ablation, has demonstrated both impressive and promising outcomes. However, these treatments have not yet fully replaced pharmaceutical approaches, primarily due to the relatively high incidence of atrial fibrillation recurrence post-procedure. Recent insights into endothelial dysfunction have shed light on its role in both the onset and progression of atrial fibrillation. This emerging understanding suggests that endothelial function might significantly influence the effectiveness of catheter ablation. Consequently, a deeper exploration into endothelial dynamics could potentially elevate the status of catheter ablation, positioning it as a primary treatment option for atrial fibrillation.

Non-Alcoholic Fatty Liver Disease and Echocardiographic Parameters of Left Ventricular Diastolic Function: A Systematic Review and Meta-Analysis

The cardiovascular implications of non-alcoholic fatty liver disease (NAFLD) have been associated with heart failure with preserved ejection fraction (HFpEF). The purpose of this review was to conduct a bibliographic search regarding the correlation between NAFLD and the echocardiographic parameters of left ventricular diastolic function. A systematic literature search was conducted in PubMed and Embase for original research data reporting on the association of NAFLD with diastolic function markers [E/e', left atrial volume index (LAVi), left ventricular mass index (LVMi)]. Meta-analysis was performed using the meta and dmetar packages in R studio v.1.4.1106, with p < 0.05 values being considered significant. Results are expressed as the standardized mean difference (SMD) for continuous variables and as the odds ratio (OR) for categorical variables, with respective 95% confidence intervals (CI). Heterogeneity between studies was expressed with index Ι2. From the preliminary search, 2619 articles were found from which 31 studies were included in the final statistical analysis. The meta-analysis of 8 studies which reported on the prevalence of diastolic dysfunction showed that it was increased in patients with NAFLD (OR: 2.07, 95% CI 1.24-3.44 with p = 0.01, I2: 80% with p < 0.01). The meta-analysis of 21 studies showed significantly higher E/e' in NAFLD patients (SMD 1.02, 95% CI 0.43-1.61 with p < 0.001, I2: 97% with p < 0.001). Individuals with NAFLD had increased LAVi (SMD: 0.87, 95% CI 0.38-1.37 with p < 0.001, I2: 96% with p < 0.001) and LVMi (SMD: 0.89, 95% CI 0.31-1.48 with p = 0.003, I2: 100% with p < 0.001). To conclude, in the meta-analysis of 31 observational studies, NAFLD patients were found to have affected left ventricular diastolic function, supporting the hypothesis of NAFLD being associated with HFpEF.

Lipoprotein(a) and calcific aortic valve disease initiation and progression: a systematic review and meta-analysis

Although evidence indicates the association of lipoprotein(a) [Lp(a)] with atherosclerosis, the link with calcific aortic valve disease (CAVD) is unclear. This systematic review and meta-analysis explores the connection between Lp(a) and aortic valve calcification and stenosis (AVS). We included all relevant studies, indexed in eight databases, up to February 2023. A total of 44 studies (163 139 subjects) were included, with 16 of them being further meta-analysed. Despite considerable heterogeneity, most studies support the relationship between Lp(a) and CAVD, especially in younger populations, with evidence of early aortic valve micro-calcification in elevated-Lp(a) populations. The quantitative synthesis showed higher Lp(a) levels, by 22.63 nmol/L (95% CI: 9.98-35.27), for patients with AVS, while meta-regressing the data revealed smaller Lp(a) differences for older populations with a higher proportion of females. The meta-analysis of eight studies providing genetic data, revealed that the minor alleles of both rs10455872 and rs3798220 LPA gene loci were associated with higher risk for AVS (pooled odds ratio 1.42; 95% CI: 1.34-1.50 and 1.27; 95% CI: 1.09-1.48, respectively). Importantly, high-Lp(a) individuals displayed not only faster AVS progression, by a mean difference of 0.09 m/s/year (95% CI: 0.09-0.09), but also a higher risk of serious adverse outcomes, including death (pooled hazard ratio 1.39; 95% CI: 1.01-1.90). These summary findings highlight the effect of Lp(a) on CAVD initiation, progression and outcomes, and support the early onset of Lp(a)-related subclinical lesions before clinical evidence.

Impact of Evolution of Self-Expandable Aortic Valve Design: Peri-Operative and Short-Term Outcomes

A few data exist on the differences of implantable aortic valve bio-prostheses. We investigate three generations of self-expandable aortic valves in terms of the outcomes. Patients undergoing transcatheter aortic valve implantation (TAVI) were allocated into three groups according to the valve type: group A (CoreValve^TM), group B (Evolut^TMR) and group C (Evolut^TMPRO). The implantation depth, device success, electrocardiographic parameters, need for permanent pacemaker (PPM), and paravalvular leak (PVL) were assessed. In the study, 129 patients were included. The final implantation depth did not differ among the groups (p = 0.07). CoreValve^TM presented greater upward jump of the valve at release (2.88 ± 2.33 mm vs. 1.48 ± 1.09 mm and 1.71 ± 1.35 mm, for groups A, B, and C, respectively, p = 0.011). The device success (at least 98% for all groups, p = 1.00) and PVL rates (67% vs. 58%, vs. 60% for groups A, B, and C, respectively, p = 0.64) did not differ. PPM implantation within 24 h (33% vs. 19% vs. 7% for groups A, B, and C, respectively, p = 0.006) and until discharge (group A: 38% vs. group B: 19% and group C: 9%, p = 0.005) was lower in the newer generation valves. Newer generation valves present better device positioning, more predictable deployment, and fewer rates of PPM implantation. No significant difference in PVL was observed.

Impaired left ventricular deformation and ventricular-arterial coupling in post-COVID-19: association with autonomic dysregulation

Coronavirus disease-19 (COVID-19) has extended implications namely the long COVID-19 syndrome. We assessed over-time changes in left ventricular (LV) function, aortic stiffness, autonomic function, and ventricular-arterial coupling (VAC) in post-COVID-19 patients. We followed 34 post-COVID-19 subjects, up to 6 months post-hospital discharge. Subjects without COVID-19 served as control. We evaluated LV global longitudinal strain (LV-GLS), arterial stiffness [carotid-femoral pulse wave velocity (cf-PWV)], and heart rate variability -standard deviation of normal RR intervals (SDNN). VAC was estimated as the ratio of cf-PWV to LV-GLS. Post-COVID-19 individuals (1-month post-hospital discharge) presented with impaired LV-GLS [-18.4%(3.1) vs. -22.0%(2.7), P < 0.001], cf-PWV [12.1 m/s (3.2) vs. 9.6 m/s (1.9), P < 0.001], SDNN [111.3 ms (22.6) vs. 147.2 ms (14.0), P < 0.001], and VAC [-0.68 (0.22) vs. -0.44 (0.10), P < 0.001] compared to control. LV-GLS, SDNN, and VAC improved at the 6-month follow-up however they did not reach control levels. In post-COVID-19 subjects, SDNN and VAC were correlated at the 1-month (R = 0.499, P = 0.003) and 6-month (R = 0.372, P = 0.04) follow-up. Long COVID-19 syndrome was associated with impaired LV-GLS, SDNN, and VAC. Post-COVID-19 subjects presented with autonomic dysregulation associated with aortic stiffness, ventricular-arterial impairment, and LV dysfunction, even 6-months post-hospital discharge. These abnormalities may be related to the presence of long COVID-19 syndrome.

Lipoprotein (a) Levels and Abdominal Aortic Aneurysm. A Systematic Review and Meta-analysis

BACKGROUND

Several studies have linked high Lipoprotein (a) (Lp(a)) concentrations to cardiovascular events, including the formation of Abdominal Aortic Aneurysms (AAA). We review and meta-analyze existing evidence on the association of Lp(a) levels with AAA.

METHODS

Studies evaluating the link of Lp(a) with AAA, up to December 27th 2021, were identified by a systematic search of PubMed, SCOPUS, and Web of Science databases. The results were qualitatively and quantitatively synthesized according to PRISMA guidelines. Results are presented as standardized mean differences (SMD) with 95% confidence intervals (CI).

RESULTS

A total of 5,078 subjects (1,637 patients with AAA vs. 3,441 controls) from 11 studies were included in the meta-analysis, with a mean age of 69.9 years and a male sex prevalence of 85.8%. Based on the qualitative synthesis, high Lp(a) concentrations are linked to abdominal aortic wall degradation and extracellular matrix disarrangement. Moreover, despite the considerable variability among races, high Lp(a) levels are related to increased AAA risk, independently of race differences. Accordingly, patients with AAA displayed significantly higher Lp(a) levels compared to controls (SMD: 0.86, 95% CI: 0.55-1.17, p < 0.001). The outcome was not affected in a sensitivity analysis excluding three outlying studies (SMD: 0.40, 95% CI: 0.22-0.58, p < 0.001).

CONCLUSION

This meta-analysis indicates the association between high Lp(a) levels and the presence of AAA, although existing literature presents high heterogeneity. Further studies are needed to standardize Lp(a) measurements and to conclude whether Lp(a) can be used as a sensitive biomarker of early presymptomatic AAA diagnosis.

Residual Right-to-Left-Shunt Following Transcatheter Patent Foramen Ovale Closure: The Role of Antithrombotic Treatment

BACKGROUND

Transcatheter closure of patent foramen ovale (PFO) is a highly effective therapy for patients with left circulation thromboembolism, not attributable to other conditions.

OBJECTIVES

This retrospective cohort study investigates the impact of baseline foramen ovale anatomy on the severity of the postclosure shunt.

METHODS

Patients with PFO, who underwent percutaneous closure, were followed up for at least 5 years postimplantation. Patients were classified into two groups based on the presence of high-risk features of the baseline PFO anatomy. At the follow-up follow-up, residual right-to-left shunt was assessed for the high and non-highrisk anatomy groups, via transcranial Doppler at rest and after performing the Valsalva maneuver, with the injection of agitated saline.

RESULTS

38 patients were examined after a mean follow-up period of 9 ± 3 years after implantation. After retrospective evaluation of the baseline transthoracic and transesophageal echo studies, 14 patients with high-risk PFO anatomy were identified. The degree of the residual right-to-left shunt, as assessed by the number of microbubbles was higher in the high-risk PFO anatomy group compared to the non-high-risk group, both at rest [1.50 (IQR: 0.00-3.25) vs. 0.00 (IQR: 0.00-0.00), p < 0.001] and post-Valsalva maneuver [7.50 (IQR: 1.50- 10.25) vs. 0.00 (IQR: 0.00-3.75), p = 0.003]. Furthermore, in the high-risk group, more microbubbles were detected at rest (p = 0.008) and post-Valsalva (p = 0.002) in subjects without antiplatelet treatment compared to subjects on prolonged antiplatelet therapy.

CONCLUSION

Baseline PFO anatomy affects the severity of the residual right-to-left shunt. Prolonged antiplatelet therapy may benefit patients with high-risk anatomical features.

Interleukin-1 in Coronary Artery Disease

Cardiovascular disease is the leading cause of mortality worldwide. Inflammation has long been established as a key component in the pathophysiology of coronary artery disease. The interleukin-1 family consists of 11 members that regulate the inflammatory response through both pro- and anti-inflammatory properties with the Nod-like receptor (NLR) family pyrin domain containing 3 inflammasome having a pivotal role in the process of converting interleukin-1 beta and interleukin-18, two key inflammatory mediators, into their mature forms. Interleukin-1 affects various cell types that participate in the pathogenesis of atherosclerosis as it enhances the expression of leukocyte adhesion molecules on the surface of endothelial cells augment the permeability of the endothelial cell barrier, attracting monocytes and macrophages into the vessel wall and aids the migration of smooth muscle cells toward atheroma. It also enhances the aggregation of low-density lipoprotein particles in endothelium and smooth muscle cells and exhibits procoagulant activity by inducing synthesis, cell-surface expression and release of tissue factor in endothelial cells, promoting platelet adhesion. The value of interleukin-1 as a diagnostic biomarker is currently limited but interleukin-1 beta, interleukin-18 and interleukin-37 have shown promising data regarding their prognostic value in coronary artery disease. Importantly, target anti-inflammatory treatments have shown promising results regarding atherosclerosis progression and cardiovascular events. In this review article we focus on the immense role of interleukin-1 in atherosclerosis progression, inflammation cascade and in the clinical application of target anti-inflammatory treatments.

Impaired heart rate variability one and six months post acute COVID-19

Background

Long COVID-19 syndrome is an increasingly recognized problem. Post-infectious cardiac autonomic dysfunction is commonly reported. This study aims to evaluate autonomic dysfunction by means of Heart rate variability (HRV) on post-COVID-19 patients.

Methods

Hospitalized patients for COVID-19 (either at the medical ward or Intensive Care Unit (ICU)) were followed up at 1 and 6 months after hospital discharge. Medical history and clinical information were collected. HRV was assessed by 24-hour ambulatory electrocardiography Holter, with the measure of the standard deviation of normal RR intervals in 24 h, ms (SDNN). The comparison was conducted with age and sex-matched non-COVID-19 controls.

Results

Thirty-four patients hospitalized with COVID-19 (20.6% admitted in ICU) were examined 1-month and 6-months post-hospital discharge. SDNN was significantly (p<0.001) reduced in the COVID-19 group (111±23 ms) compared to the control subjects (152±24 ms) 1-month after discharge. Subgroup analysis between COVID-19 group revealed that ICU subjects presented significantly (p<0.001) reduced SDNN compared to the medical ward, respectively (83±20 ms vs. 118±17 ms). At 6-months, an improvement was noted at SDNN 24h (6-month: 133±24 vs. control: 151±24 ms, p=0.004; 1-month: 111±23 ms vs. 6-month: 133±24 ms, p<0.001). Also at 6-months, ICU subjects noted significantly (p=0.003) reduced SDNN 24h compared to medical ward subjects (107±17 ms vs. 140±20 ms). On the 6-months follow-up, 32% of the subjects had “long-COVID-19” symptoms. Subjects with long COVID-19 symptoms had low SDNN values (“long-COVID-19”: 112±17 ms vs. non-“long-COVID-19”: 142±20 ms, p=0.001)

Conclusion

Patients hospitalized for COVID-19 have reduced SDNN, at one month post-hospital discharge which is improved at the six months follow-up. These findings emphasize the increased sympathetic drive activity in the post-acute COVID-19 phase and imply a link between autonomic dysfunction and long COVID-19.

Funding Acknowledgement

Type of funding sources: None.

The role of cardiometabolic risk factors and endothelial dysfunction in serum albumin levels and capillary leak syndrome of patients with COVID-19

Background

Growing evidence focuses on the role of hypoalbuminemia in the COVID-19 course and the role of vascular inflammation in the progression to Capillary Leak Syndrome (CLS). CLS may be mediated by a derangement of endothelial barrier following vascular endothelial dysfunction. We investigated the role of cardiometabolic risk factors in the association of hypoalbuminemia with endothelial dysfunction of hospitalized COVID-19 patients.

Methods

In this cross-sectional study, patients hospitalized for COVID-19 at the medical ward or Intensive Care Unit (ICU) were enrolled. Medical history and laboratory examinations were collected while the endothelial function was assessed by brachial artery flow-mediated dilation (FMD) between the first 24–72 hours of their admission to the hospital. According to the body mass index, history of hypertension, dyslipidemia, and diabetes mellitus, COVID-19 patients were categorized in those with Cardiometabolic Risk Factors (CRFact) or without CRFact (no-CRFact). From the study population, we excluded subjects with established cardiovascular disease.

Results

Sixty-six patients with COVID-19 (37% admitted in ICU) were recruited. From the study population, 41 were in the group of CRFact and 25 in the no-CRFact. Patients with CFRact were older (65±9 years vs. 53±14 years, p<0.001), had more impaired FMD (1.16±2.13% vs. 2.60±2.44%, p=0.01), and lower serum albumin levels (3.10±0.68 g/dL vs. 3.52±0.26 g/dL, p=0.006) compared to the no-CRFact group. Between CRFact and no-CRFact, there was no difference in CRP and IL-6 levels. Interestingly, serum albumin in patients with CRFact was significantly lower than the lower reference limit (LRL) (=3.5 g/dl) of albumin (p=0.001), while no such finding was noted in subjects with no CRFact (p=0.64). Furthermore, regression analysis revealed that, even after adjustment for age, the presence of CRFact was associated with decreased serum albumin levels by 0.31mg/dl (95% CI 0.08 to 0.63, p=0.04). In the CRFact population, there was a correlation of albumin with FMD (R=0.29, p=0.05) and an inverse correlation with CRP (rho=−0.48, p=0.02) and IL-6 (rho=−0.66, p<0.001), while in the no-CRFact group no such correlation were observed (p=NS for all).

Conclusion

COVID-19 patients with cardiometabolic risk factors present with low serum albumin levels early at the course of the disease, which may be driven by endothelial dysfunction and vascular inflammation. This data gives insights into the potential association of a dysfunctional endothelial layer and the progression to capillary leak syndrome.

Funding Acknowledgement

Type of funding sources: None.

Inside the “brain” of an artificial neural network: an interpretable deep learning approach to paroxysmal atrial fibrillation diagnosis from electrocardiogram signals during sinus rhythm

Background

With the ongoing, rapid advances in Deep Learning (DL), such solutions can now detect medical conditions even invisible to the human eye. In this direction, efforts have been made to develop DL algorithms that diagnose paroxysmal atrial fibrillation (PAF) from electrocardiogram (ECG) signals in sinus rhythm (SR). However, many of the available approaches function as “black boxes”, with physicians unable to understand and trust their predictions.

Purpose

To train a DL model to detect PAF patients while in SR and apply an algorithm that interprets and visualises its decisions.

Methods

We obtained ECG samples from PAF and non-PAF patients during SR, from the PAF Prediction Challenge Database. After discarding unannotated samples and augmenting the sample size (by dividing each signal into 30-second segments), we split the whole dataset into a train (68%), a validation (16%) and a test (16%) set. No pair of samples belonging to different sets originated from the same patient. We trained the InceptionTime neural network on the train/validation sets and tested on the “unseen” test set after “hiding” the correct answers. Its performance was evaluated with the following metrics: Accuracy, f1-score, precision and recall (sensitivity). After repeating this process 20 times, we obtained a distribution for each score. Finally, we adjusted the Grad-CAM interpretation algorithm to our data and used it to visualise the areas perceived as important by the model.

Results

After pre-processing, 4,080, 30-second, two-lead ECG signals were allocated to the train set, 960 to the validation and 960 to the test set. Each subset contained an equal number of PAF and non-PAF samples. After repeated training and testing, we obtained a median accuracy of 0.84 (interquartile range, IQR: 0.66–0.88), an f1-score of 0.82 (IQR: 0.68–0.88) and a median precision and recall equal to 0.93 (IQR: 0.67–0.99) and 0.77 (IQR: 0.68–0.93), respectively. The Grad-CAM technique highlighted the ECG areas of interest that led to each decision. We selected and present both PAF-positive and -negative samples, perceived either correctly or falsely. Interestingly, correct model decisions tend to focus on the P-wave, while false ones fixate on other regions.

Conclusions

Although a pilot study with considerable limitations (small sample size, disregard of possible confounding due to comorbidities or other factors), this work shows how DL can be employed to distinguish between PAF and non-PAF patients from SR ECG samples, and confirms the potential of DL-enabled approaches to offer novel diagnostic capabilities. Most importantly, our effort provides a comprehensible, visual interpretation of the model's decisions. Demystifying DL behaviour can, not only improve such efforts by explaining false decisions, but also cultivate trust among clinicians and, possibly, point out directions for future research, since we can now see through the magnifying lens of a neural network.

Funding Acknowledgement

Type of funding sources: None.

The complex relationship between diabetes and cardiac arrhythmias: Pathophysiology and mechanisms

Coronary artery disease, autonomic neuropathy, and diabetic cardiomyopathy are the most common cardiovascular complications of diabetes. However, emerging evidence demonstrates that diabetes also affects the heart's electrical conduction system, culminating in lethal arrhythmias and sudden cardiac death. Diabetes and rhythm disturbances have a complex relationship, and arrhythmias cannot be attributed to ischemia and autonomic neuropathy only. Hypoglycemia, hyperglycemia, and glucose fluctuations can potentially induce arrhythmias by activating various pathways. Structural remodeling can accelerate and exacerbate disease development. Mitochondrial dysfunction can also alter the structure and metabolism of cardiomyocytes and contribute to disease progression through oxidative stress and inflammation.

Optimising and validating deep learning approaches for diagnosing atrial fibrillation from few-lead ambulatory electrocardiogram signals

Funding Acknowledgements

Type of funding sources: None.

Background

Deep learning (DL) has received much attention as a solution for automatically diagnosing atrial fibrillation (AF) from raw ECG signals. However, few studies exist to investigate how DL approaches can be optimally configured and whether their diagnostic performance is externally validated.

Purpose

To explore how signal-related parameter tuning affects the ability of DL approaches to diagnose AF and validate the optimal approach internally and externally.

Methods

We applied two dedicated DL models (InceptionTime and MINIROCKET) on a set of 7,966 AF and non-AF (normal or with other abnormalities) ambulatory ECG samples, originating from the MIT-BIH AF, MIT-BIH Normal Sinus Rhythm and Long Term AF databases. We tested the effect of different sample lengths (30sec (s), 10s, 30/10s -30s with a "sliding window" of 10s-), sampling frequencies (200, 100, 50 Hz) and lead numbers (two-, single-), and the role of denoising (Discrete Wavelet Transformation, no denoising) on the ability to diagnose AF, by measuring ROC AUC and sensitivity (SEN) after repeated model training and testing. Under the optimal configuration, we trained 10 replicas of both models on 90% of the data and tested their performance on the remaining 10% (internal validation). Finally, we applied both pre-trained models on a separate dataset (MIT-BIH Arrhythmia) to determine their external validity.

Results

Although the diagnostic performance did not differ between 30s and 10s signals, the 30/10s setting displayed significantly higher median AUC (0.98) and sensitivity (97.3%, p&lt;0.05 for all comparisons). Signals sampled at 50Hz performed poorer (AUC=0.88, SEN=79.9%) than those at 100Hz (AUC=0.92, SEN=88.7%) and 200Hz (AUC=0.93, SEN=89.2%), although this difference slightly failed to reach statistical significance. Despite denoised signals showing a higher median AUC (0.95 vs. 0.92) and sensitivity (92.8% vs. 88.7%), the difference was not found significant. Similarly, two-lead signals performed better than single-lead ones (AUC=0.92 vs. 0.9 and SEN=88.7% vs. 84.1%, respectively), but without crossing the significance threshold. The internal validation with denoised, 30/10s, two-lead signals, at 100Hz, yielded similarly high performance metrics for both InceptionTime and MINIROCKET (AUC=0.98, SEN=96.9% and AUC=0.98, SEN=97.4%, respectively). In contrast, the performance on the external set dropped significantly (AUC=0.79, SEN=81.4% and AUC=0.72, SEN=83.7%, respectively, p&lt;0.001 for all comparisons).

Conclusions

Both DL approaches can effectively detect AF in ambulatory ECG signals, with only 3 out of 100 cases missed, designating their promising utility as screening tools for automated AF detection. While optimising tunable parameters can enhance the internal performance of such efforts, their external validation is necessary to establish their robustness "in the wild", since their performance on "unseen" data can be, similarly to our case, notably lower.

Association between excessive supraventricular ectopic activity and future diagnosis of atrial fibrillation in patients with cryptogenic stroke

Funding Acknowledgements

Type of funding sources: None.

Background

The relationship between the excessive supraventricular ectopic activity (ESVEA) and the subclinical atrial fibrillation (AF) in patients with cryptogenic stroke is yet not fully understood.

Purpose

The aim of this study is to examine the prognostic significance of ESVEA for the development of AF in those patients.

Methods

The study retrospectively included 124patients, hospitalized for a cryptogenic stroke between 2014 and 2015. Twenty-four hour inpatient Holter monitoring, was used to define ESVEA as the presence of ≥20 premature atrial complexes per hour (PACs/h), along with a duration of the longest run of supraventricular tachycardia (LSVR) ≥5 seconds. After approximately 5 years of follow-up, the patients were examined for AF.

Results

The remaining 111 patients(12 died and 1 was lost during follow-up) had a median age of 56 and 13 (11.71%) of them were diagnosed with AF (AF patients). The median value of CHA2DS2-VASc score was 3 and was similar for the two groups (p=0.252). Patients with AF had a significantly higher number of PACs/h and a longer duration of LSVR compared to nonAF patients (16.67 vs. 0.21, p&lt;0.001 and 3 vs. 0 seconds, p&lt;0.001, respectively). The existence of ESVEA was also significantly more prevalent among the AF patients (46.15%, 95% CI: 17.78% - 74.22%) compared to non-AF ones (6.1%, 95% CI: 1.3% - 10.7%, p&lt;0.001). ROC analysis revealed the high diagnostic test accuracy of both PACs/h and LSVR for AF. The area under the curve was 97.2% (p&lt;0.001) for PACs/h and 81.1% (p&lt;0.001) for LSVR.

Conclusions

Excessive atrial ectopy, detected with 24h inpatient Holter monitoring, is a significant indicator of future development of AF, in patients presenting originally with a cryptogenic stroke.

Expression of Tissue microRNAs in Ascending Aortic Aneurysms and Dissections

Little is known about the role of serum and tissue mediators in the progression of ascending aortic aneurysms and dissections. We examined how the tissue expression of microRNAs and matrix metalloproteinases (MMPs), as well as the serum levels of osteoprotegerin, adiponectin, and high sensitivity C-reactive protein (hsCRP) are associated with these entities. We enrolled 21 patients with ascending aortic aneurysm, 11 with acute Stanford type A aortic dissection and 18 controls. The serum levels of osteoprotegerin, adiponectin, and hsCRP, as well as the tissue expression of MMPs 2 and 9 and tissue microRNAs 29 and 195 were compared among groups. There was no difference regarding serum osteoprotegerin, adiponectin, and tissue MMP2 and MMP9 levels. hsCRP was higher in the dissection group (P = .03). Tissue expression of microRNA 29 was 2.11-fold higher in the dissection (P = .001) and 2.99-fold higher in the aneurysm group (P < .001), compared with the control group. Tissue expression of microRNA 195 was 2.72-fold higher in the dissection (P < .001) and 2.00-fold lower in the aneurysm group (P = .08), compared with to the control group. These findings support the contribution of microRNAs in the progression of aneurysm formation and dissection, suggesting a role as potential biomarkers and future therapeutic targets.

The Role of Endothelial Related Circulating Biomarkers in COVID-19. A Systematic Review and Meta-analysis

BACKGROUND

Several studies have revealed the link between Coronavirus Disease 2019 (COVID-19) and endothelial dysfunction. To better understand the global pattern of this relationship, we conducted a meta-analysis on endothelial biomarkers related to COVID-19 severity.

METHODS

We systematically searched the literature up to March 10, 2021, for studies investigating the association between COVID-19 severity and the following endothelial biomarkers: Intercellular Adhesion Molecule 1 (ICAM-1), Vascular Cell Adhesion Molecule 1 (VCAM-1), E-selectin, P-selectin, Von Willebrand Factor Antigen (VWF-Ag), soluble Thrombomodulin (sTM), Mid-regional pro-adrenomedullin (MR-proADM), and Angiopoietin-2 (Ang-2). Pooled estimates and mean differences (PMD) for each biomarker were reported.

RESULTS

A total of 27 studies (n=2213 patients) were included. Critically ill patients presented with higher levels of MR-proADM (PMD: 0.71 nmol/L, 95% CI: 0.22 to 1.20 nmol/L, p=0.02), E-selectin (PMD: 13,32 pg/ml, 95% CI: 4,89 to 21,75 pg/ml, p=0.008), VCAM-1 (PMD: 479 ng/ml, 95% CI: 64 to 896 ng/ml, p=0.03), VWF-Ag (PMD: 110.5 IU/dl, 95% CI: 44.8 to 176.1 IU/dl, p=0.04) and Ang-2 (PMD: 2388 pg/ml, 95% CI: 1121 to 3655 pg/ml, p=0.003), as compared to non-critically ill ones. ICAM-1, P-selectin and thrombomodulin did not differ between the two groups (p>0.05).

CONCLUSION

Endothelial biomarkers display significant heterogeneity in COVID-19 patients, with higher MR-proADM, E-selectin, VCAM-1, VWF-Ag, and Ang-2 levels being associated with increased severity. These findings strengthen the evidence on the key role of endothelial dysfunction in disease progress.

Tissue microRNA expression in aortic aneurysm dissection

Background

Dissection and other complications of ascending aortic aneurysms are potentially life-threatening. Several factors may be implicated in aneurysm progression and dissection. The role of tissue microRNAs may be of interest.

Purpose

To examine how serum biomarkers and tissue expression of microRNAs are associated with thoracic aortic aneurysms and dissection.

Methods

We compared three groups of patients; 21 patients with aneurysm of the aortic root, ascending aorta or aortic arch undergoing scheduled repair, 11 patients with acute Stanford type A aortic dissection who underwent emergency surgery and 18 patients with normal aortic diameter undergoing other cardiac surgery (control group). Prior to surgery, peripheral blood samples were obtained from patients, to assess osteoprotegerin and adiponectin levels with the ELISA method. Tissue samples from ascending aortic wall were obtained from patients during surgery. Following appropriate storage and homogenization, tissue Matrix Metalloproteinases (MMPs) 2 and 9 were measured with the ELISA method, while tissue microRNAs 29 and 195 were measured using qrtPCR, after RNA extraction.

Results

There was no significant difference among control, aneurysm and dissection groups in terms of age (62±10 years vs 66±12 years vs 59±12 years, p=0.052), gender distribution (77.8% male vs 81% male vs 90% male, p=0.28) or BMI (28.51±2.92 kg/m2 vs 25.72±3.09 kg/m2 vs 27.02±3.2 kg/m2, p=0.76). There was also no difference among control, aneurysm and dissection groups regarding hypertension (72% vs 62% vs 73%, p=0.73), diabetes mellitus (22% vs 19% vs 36%, p=0.54), smoking (44% vs 29% vs 46%, p=0.09) or dyslipidemia (78% vs 43% vs 55%, p=0.08). The groups of control subjects, aneurysms and dissections did not differ in osteoprotegerin [44 (28, 52) pmol/l vs 31 (28, 37) pmol/l vs 45 (24, 71) pmol/l, p=0.17], adiponectin [6,65 (2,39, 9,79) μg/ml vs 5,28 (2,34, 6,98) μg/ml vs 4,13 (2,49, 7,52) μg/ml, p=0.43], tissue MMP2 [0.97 (0.42, 27.66) ng/ml vs 9.12 (1.72, 61.49) ng/ml vs 2.51 (0.22, 235.72) ng/ml, p=0.34] and tissue MMP9 levels [0.96 (0.29, 8.56) ng/ml vs 10.31 (1.18, 25.58) ng/ml vs 2.76 (0.63, 54.83) ng/ml, p=0.09] (Figure 1). Importantly, tissue expression of mir29 was 2.11-fold higher in the dissection group (p=0.001) and 2.99-fold higher in the aneurysm group (p&lt;0.001) compared to the control group. Tissue expression of mir195 was 2.72-fold higher in the dissection group (p&lt;0.001) and 2.00-fold lower in the aneurysm group (p=0.08) compared to the control group (Figure 2).

Conclusions

These findings highlight the role of epigenetic modifications through altered microRNA tissue expression in aortic wall synthesis, extracellular matrix degradation and progress of aneurysm formation and dissection. The exact role of microRNA expression in aortic dilatation and dissection, as well as their role as potential biomarkers, merit further validation.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

The effect of diabetes mellitus on in-hospital hyperglycemia, length of stay and survival in patients with brain tumor receiving dexamethasone: A descriptive and comparative analysis

OBJECTIVES

To perform a comparative analysis on the impact of Type 2 Diabetes Mellitus (DM) on in-hospital hyperglycemia, length of stay (LOS) and survival of patients suffering from brain tumor who receive dexamethasone.

PATIENTS AND METHODS

Patients with brain tumor hospitalized in a Neurosurgery department between 2011 and 2018, were studied. Data referring to medical history, clinical characteristics and in-hospital survival was collected and analyzed. Morning plasma glucose levels (PGL) were obtained for seven consecutive days after the start of dexamethasone.

RESULTS

Fifty-six patients were identified. Of them, 21 (37.5%) were diabetic. During dexamethasone administration, a difference in morning PGL values during different days was noted (p = 0.003). No difference in glucose levels among different glucocorticoid doses was seen. DM was associated with higher average PGL (aMPGL), calculated as the mean of morning PGL values for the last six days (p = 0.001) and with higher rates of persistent hyperglycemia (p = 0.002). The change of aMPGL from the morning PGL value of day one did not differ between the two cohorts (p = 0.729). DM neither affected LOS nor in-hospital survival (p = 0.745 & p = 0.438, respectively).

CONCLUSION

Although morning glucose values were higher in diabetic, compared to non-diabetic patients, their change from day one was similar between the two cohorts. LOS and in-hospital survival were not affected by DM.

The Mechanisms of Actions of Aldosterone and its Antagonists in Cardiovascular Disease

Background:

Aldosterone, through its actions on Mineralcorticosteroid Receptors (MR), controls fluid and electrolyte balance, but also exerts various direct deleterious actions on the vasculature. A number of aldosterone antagonists have been manufactured to reverse these effects.

Objective:

A comprehensive review of the underlying mechanisms of the actions of aldosterone and its antagonists in cardiovascular disease.

Method:

The relevant studies indexed in PubMed, Scopus and Google Scholar databases, published from 2003 to May 2018 were identified and reported.

Results:

Aldosterone binds to MR, activating them as intracellular transcription factors. Moreover, aldosterone, through its actions on MR, as well as on another not fully explored class of receptors, triggers several signaling pathways that produce rapid, non-genomic actions. In the vasculature, all these changes favor the establishment of inflammation and cardiovascular dysfunction, which, in turn, lead to or exacerbate various cardiovascular diseases. Mineralcorticosteroid Antagonists (MRA) are compounds that antagonize the action of aldosterone on MR. Spironolactone was the first steroidal MRA to be commercially used. It showed beneficial clinical results, but also a number of adverse effects. The next generation of steroidal MRA, exhibited lower potency but did not induce many of these adverse reactions, due to their high selectivity for MR. The third generation of MRA compromises the newly introduced non-steroidal MRA, which have a completely different chemical structure, they induce different and more drastic changes to MR, they are much more specific and currently under clinical trials.

Conclusion:

New MRA, which block the aldosterone induced pathways in the vasculature, hold promising results for the treatment of cardiovascular disease.

Optimizing engagement of undergraduate students in medical education research: The eMERG training network

Background

The practice of evidence-based medicine and critical appraisal are essential for the modern doctor. Early engagement of medical students in research methodology is considered as a rising need for most medical school curricula; however, few peer-reviewed initiatives have been reported so far. We developed a Medical Education Research Group (eMERG) as part of a novel undergraduate surgical masterclass, which aimed to train undergraduate students on basic research methodology, as well as to motivate them to pursue a clinical and academic career in surgical specialties.

Methods: eMERG consists of an international structured network of senior academics, consultant-level clinicians, senior and junior trainees who support undergraduate trainees. Students are selected from a competitive pool of applicants. Several small prospective studies in skills-based education, as well as systematic reviews on similar topics, have run under the umbrella of this framework, in the form of scholarship awards. Structured feedback questionnaires were distributed to evaluate the experience of the first three years.

Results

12 students have participated in this pilot initiative. 11 manuscripts have been submitted for publication and 8 were accepted following peer-review in MEDLINE-indexed journals. Delegates perceived this experience as an excellent training opportunity which improved their research productivity. Delegates also stated engagement in research developed interest in the relevant surgical speciality, impacting their career aspirations.

Conclusions

eMERG is one of the first reported European educational research networks for undergraduates. Research outcomes and students' perceptions conclude that eMERG enhances engagement with research methodology and motivation towards a career in surgery.

•

eMERG is a pilot international research training network where medical students receive support to conduct research in Medical Education.

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eMERG structure can serve as a novel model to convey research experience from one generation to another, and in the same time, motivate and aspire students to develop leadership skills.

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eMERG was developed in a financial crisis environment with promising research outputs and positive students' feedback.

Sodium-glucose Cotransporter 2 Inhibitors: The Pleiotropic Mechanisms of Actions

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT-2) inhibitors are a new class of oral antidiabetic drugs. So far, there are three agents approved for use in Europe and in the USA, two in Japan and another four agents under testing.

OBJECTIVE

The purpose of this study is to describe the mechanism of action and the favorable and adverse effects of SGLT-2 inhibitors.

METHOD

A thorough review of literature indexed in PubMed, Scopus and Cochrane databases were conducted. Original papers, review papers and their relevant references in English, from 2005 to February 2017, were included.

RESULTS

The main mechanism of action is the glycosuria induced by the inhibition of SGLT-2, located in the early segment of the proximal convoluted tubule. Along with large amounts of glucose, sodium, water and uric acid are also excessively excreted in urine. These actions have various, both desired and adverse, consequent implications in kidneys, blood pressure, cardiovascular system and other systems. Moreover, SGLT-2 inhibitors act directly to organs other than the kidneys, as SGLT-2 can be expressed there.

CONCLUSION

The underlying mechanisms responsible for the SGLT-2 inhibitor actions, are pleiotropic and occur in the kidneys, as well as in other target organs. The comprehension of these mechanisms, not only permits us to understand their actions better, but it could also help us to predict more of their undisclosed favorable actions, as well as their rare adverse effects.

Is In-Vivo laparoscopic simulation learning a step forward in the Undergraduate Surgical Education?

BACKGROUND

Essentials Skills in the Management of Surgical Cases - ESMSC is an International Combined Applied Surgical Science and Wet Lab course addressed at the Undergraduate level. Laparoscopic Skills is a fundamental element of Surgical Education and various Simulation-Based Learning (SBL) models have been endorsed. This study aims to explore if there is any significant difference in delegates' performance depending on whether they completed In Vivo module prior to the equivalent in the laparoscopic simulator.

MATERIALS AND METHODS

37 Medical Students from various EU countries were divided in 2 groups, and both completed the "Fundamentals in Laparoscopic Surgery" module in the Dry-lab Laparoscopic Simulator as well as the same module "In Vivo" on a swine model. Group A (18 students, 48.6%) completed the "Fundamentals in Laparoscopic Surgery - FLS" module prior to the "In Vivo", whereas group B completed the "In Vivo" module first. Direct Observation of Procedural Skills (DOPS) were used to assess delegates' performance.

RESULTS

The mean DOPS scores for the "FLS" and "In Vivo" models were 2.27 ± 0.902 and 2.03 ± 0.833, respectively, and the delegates' performance was not statistically significantly different between them (p = 0.128). There was no statistically significant difference in the scores among different gender, year of study, school and handedness groups. The alteration in the sequence between Dry-lab "FLS" and "In Vivo" modules did not affect the performance in neither the "FLS" nor the "In Vivo" models.

CONCLUSIONS

The inexpensive, but low-fidelity "FLS" model could serve an equal alternative Simulation-Based Learning model for the early undergraduate training. Our study demonstrated that high fidelity In Vivo simulation for laparoscopic skills does not affect significantly the improvement in the delegates' performance at the undergraduate level. Further studies should be conducted to identify at which stage of training should high fidelity simulation be introduced.

Promoting Undergraduate Surgical Education: Current Evidence and Students' Views on ESMSC International Wet Lab Course

BACKGROUND

Undergraduate Surgical Education is becoming an essential element in the training of the future generation of safe and efficient surgeons. Essential Skills in the Management of Surgical Cases (ESMSC), is an international, joint applied surgical science and simulation-based learning wet lab course.

METHODS

We performed a review of the existing literature on the topic of undergraduate surgical education. Following that, we analyzed the feedback questionnaire received 480 from 2 recent series of ESMSC courses (May 2015, n = 49 and November 2015, n = 40), in order to evaluate European Union students' (UK, Germany, Greece) views on the ESMSC course, as well as on the undergraduate surgical education. Results Using a 10 point graded scale, the overall ESMSC concept was positively evaluated, with a mean score of 9.41 ± 0.72 (range: 8-10) and 8.94 ± 1.1 (range: 7-10). The majority of delegates from both series [9.86 ± 0.43 (range: 8-10) and 9.58 ± 0.91 (range: 6-10), respectively] believed that ESMSC should be incorporated in the undergraduate surgical curriculum. Comparison of responses from the UK to the Greek Medical Student, as well as the findings from the third and fourth year versus the fifth and sixth year Medical Students, revealed no statistically significant differences pertaining to any of the questions (p > 0.05).

CONCLUSIONS

Current evidence in the literature supports the enhancement of surgical education through the systematic use of various modalities that provide Simulation-Based Training (SBT) hands-on experience, starting from the early undergraduate level. The findings of the present study are in agreement with these previous reports.

Medical students' satisfaction with the Applied Basic Clinical Seminar with Scenarios for Students, a novel simulation-based learning method in Greece

PURPOSE

The integration of simulation-based learning (SBL) methods holds promise for improving the medical education system in Greece. The Applied Basic Clinical Seminar with Scenarios for Students (ABCS3) is a novel two-day SBL course that was designed by the Scientific Society of Hellenic Medical Students. The ABCS3 targeted undergraduate medical students and consisted of three core components: the case-based lectures, the ABCDE hands-on station, and the simulation-based clinical scenarios. The purpose of this study was to evaluate the general educational environment of the course, as well as the skills and knowledge acquired by the participants.

METHODS

Two sets of questions were distributed to the participants: the Dundee Ready Educational Environment Measure (DREEM) questionnaire and an internally designed feedback questionnaire (InEv). A multiple-choice examination was also distributed prior to the course and following its completion. A total of 176 participants answered the DREEM questionnaire, 56 the InEv, and 60 the MCQs.

RESULTS

The overall DREEM score was 144.61 (±28.05) out of 200. Delegates who participated in both the case-based lectures and the interactive scenarios core components scored higher than those who only completed the case-based lecture session (P=0.038). The mean overall feedback score was 4.12 (±0.56) out of 5. Students scored significantly higher on the post-test than on the pre-test (P<0.001).

CONCLUSION

The ABCS3 was found to be an effective SBL program, as medical students reported positive opinions about their experiences and exhibited improvements in their clinical knowledge and skills.

Reliability of the posterolateral corner of the acromion as a landmark for the posterior arthroscopic portal of the shoulder

HYPOTHESIS

The present study aimed to evaluate the variability of the posterolateral corner of the acromion (PCA) position in relation to the glenohumeral joint, in a craniocaudal direction, to assess whether the universal use of a certain distance from that point will always lead to a consistent placement of the posterior arthroscopic portal of the shoulder.

METHODS

The study used 140 dried scapulae (36 women and 34 men). Measurements included the glenoid height and the perpendicular distance between the PCA and the most superior point of the glenoid. The percentage of coverage of the glenoid by the acromion was defined as the ratio between the 2 measurements. The Student t test was used to examine for significant differences between the sexes and the Student paired t test between sides (P < .05).

RESULTS

The average glenoid height was 3.37 ± 0.29 cm (range, 2.69-4.00 cm). The perpendicular distance between the PCA and the most superior point of the glenoid was 0.82 ± 0.69 cm (range, -0.35 to 2.27 cm). The percentage of coverage of the glenoid by the acromion was 24% ± 20% (range, -10% to 64%).

CONCLUSIONS

The position of the PCA in relation to the glenohumeral joint is quite variable. Therefore, the use of a universal distance from the PCA will not always lead to a consistent placement of the posterior arthroscopic portal of the shoulder. Future research is needed in this area to develop techniques to individualize placement of the posterior portal.

Multiplex immune serum biomarker profiling in sarcoidosis and systemic sclerosis

Multiplex protein technology has the potential to identify biomarkers for the differentiation, classification and improved understanding of the pathogenesis of interstitial lung disease. The aim of this study was to determine whether a 30-inflammatory biomarker panel could discriminate between healthy controls, sarcoidosis and systemic sclerosis (SSc) patients independently of other clinical indicators. We also evaluated whether a panel of biomarkers could differentiate between the presence or absence of lung fibrosis in SSc patients. We measured 30 circulating biomarkers in 20 SSc patients, 21 sarcoidosis patients and 20 healthy controls using Luminex bead technology and used Fisher's discriminant function analysis to establish the groups of classification mediators. There were significant differences in median concentration measurements between study groups for 20 of the mediators but with considerable range overlap between the groups, limiting group differentiation by single analyte measurements. However, a 17-analyte biomarker model correctly classified 90% of study individuals to their respective group and another 14-biomarker panel correctly identified the presence of lung fibrosis in SSc patients. These findings, if they are corroborated by independent studies in other centres, have potential for clinical application and may generate novel insights into the modulation of immune profiles during disease evolution.

Disseminated gonococcal infection in a homosexual man diagnosed by nucleic acid amplification testing from a skin lesion swab

Disseminated gonococcal infection (DGI) often presents a diagnostic challenge. Through the novel application of molecular technology, a case is presented that suggests how the diagnostic sensitivity for this systemic complication of gonococcal infection can be improved. In a typical case of DGI seen in a homosexual man in whom all mucosal and blood specimens were culture negative, nucleic acid amplification testing (NAAT) helped to confirm the diagnosis. Both throat and skin lesion specimens tested positive for gonococcal DNA and this was confirmed with a supplementary porA pseudogene NAAT. The use of adjuvant NAAT assessment is recommended as part of the diagnostic work-up for suspected DGI cases.

Intracellular cytokine profiles and T cell activation in pulmonary sarcoidosis

In granulomatous inflammatory lung diseases such as sarcoidosis, the balance of cytokine production by activated T cells in the lungs may influence clinical disease outcome. To investigate the potential of T lymphocytes to produce cytokines and contribute to this process, T cells from bronchoalveolar lavage (BAL) and PB from 19 patients with active lung disease were stimulated, stained, and analysed by flow cytometry for intracellular production of cytokines and expression of the activation marker CD69. Higher proportions of BAL cells expressed CD69 compared with PB, in the absence of in vitro stimulation. The expression of IFN-gamma was similar in unstimulated BAL and PB T cells, and there was no association between the expression of CD69 and IFN-gamma. Following stimulation, there were increased numbers of IFN-gamma(+) T cells. A similar trend was found with IL-2(+) T cells, but there were lower levels of IL-4(+) T cells in BAL compared with PB, and similar levels of IL-10(+) T cells. The presence of activated T lymphocytes in BAL samples from patients with sarcoidosis, with the potential to produce Th1 type 1 cytokines may contribute to the inflammatory processes in this granulomatous lung disease. The use of intracellular flow cytometry to investigate cytokine production by BAL T cells could help to indicate potential targets for future therapy.

Single-nucleotide polymorphisms in the SPARC gene are not associated with susceptibility to scleroderma

OBJECTIVE

SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein that modulates cell-cell and cell-extracellular matrix interactions. SPARC expression is restricted mainly to sites of tissue remodelling and wound repair, and is prominent in fibrotic disorders. Single-nucleotide polymorphisms (SNPs) in the SPARC gene are reportedly linked to scleroderma in four ethnic groups: Choctaw Indians, Caucasians, African Americans and Mexican Americans. We set out to reproduce and to positionally clone these disease associations in a set of UK Caucasian scleroderma patients and ethnically matched controls.

METHODS

One hundred and twenty-one scleroderma subjects and 200 controls were genotyped by polymerase chain reaction with sequence-specific primers differing only in the 3' nucleotide corresponding to each allele of the biallelic SNPs. Scleroderma patients were analysed against controls and on the basis of their fibrosing alveolitis status as judged by high-resolution computed tomography evaluation and the extent of cutaneous involvement.

RESULTS

Eight biallelic SNPs were genotyped: three from the last untranslated exon, which had been described previously, and an additional five novel SNPs: two in the promoter region, one in exon three and two in the 3' untranslated region. Six major haplotypes were constructed across all eight SNP positions. No significant differences in genotype, allele or haplotype frequency were observed between scleroderma and controls or within scleroderma subgroups.

CONCLUSIONS

SNPs in the SPARC gene are not associated with susceptibility to scleroderma. This research adds to the genetic knowledge of the SPARC gene by identifying five novel SNPs spanning the whole gene and inserting these within the context of clearly defined haplotypes.

BAL findings in idiopathic nonspecific interstitial pneumonia and usual interstitial pneumonia

Idiopathic pulmonary fibrosis (IPF), which has the histological pattern of usual interstitial pneumonia (UIP), is a progressive interstitial lung disease with a poor prognosis. Idiopathic interstitial pneumonias with a histological pattern of nonspecific interstitial pneumonia (NSIP) have a better prognosis than UIP, and may present with a clinical picture identical to IPF. The authors hypothesised that bronchoalveolar lavage (BAL) findings may distinguish between UIP and NSIP, and have prognostic value within disease subgroups. BAL findings were studied retrospectively in 54 patients with histologically proven (surgical biopsy) idiopathic UIP (n=35) or fibrotic NSIP (n=19), all presenting clinically as IPF. These findings were also compared with the BAL profile of patients with other categories of idiopathic interstitial pneumonias. BAL total and differential cell counts did not differ between the two groups. Survival was better in NSIP. In neither group were BAL findings predictive of survival or changes in lung function at 1 yr, even after adjustment for disease severity, smoking and treatment. BAL differential counts in fibrotic NSIP differed from respiratory bronchiolitis-associated interstitial lung disease, but not from desquamative interstitial pneumonia or cellular NSIP. The authors conclude that bronchoalveolar lavage findings do not discriminate between usual interstitial pneumonia and nonspecific interstitial pneumonia in patients presenting with clinical features of idiopathic pulmonary fibrosis, and have no prognostic value, once the distinction between the two has been made histologically.

A single round PCR method for genotyping human surfactant protein (SP)-A1, SP-A2 and SP-D gene alleles

The genes coding for the human surfactant proteins (SP)-A and SP-D are located on chromosome 10q22-q23.1. SP-D is the product of a single gene whereas SP-A is the product of two highly homologous genes SP-A1 and SP-A2. Several single nucleotide polymorphisms (SNP) are present in the SP-A1, SP-A2 and SP-D genes. Because of this high degree of sequence homology between the SP-A1 and SP-A2 genes, current genetic analysis studies employ a nested PCR/radioactive hybridization or restriction fragment length polymorphism approach to initially isolate the genes and subsequently to detect the SNP in these isolates. In this manuscript, we report the primers and conditions of a sequence specific primer-PCR methodology that enables the identification of SP-A1, SP-A2 and SP-D gene allelic variants directly on genomic DNA material.

Increased vitronectin and endothelin-1 in the breath condensate of patients with fibrosing lung disease

BACKGROUND

Non-specific interstitial pneumonia (NSIP) and fibrosing alveolitis associated with systemic sclerosis (FASSc) are diseases of unknown aetiology that are characterised by the accumulation of mononuclear cells, followed by the progressive deposition of collagen within the interstitium and subsequent destruction of lung airspace. Better understanding of mediators involved in fibrosis may be useful for early diagnosis and in clinical monitoring of disease progression.

OBJECTIVE

The aim of this study was to investigate the presence of two profibrotic markers, the vitronectin and the endothelin-1 (ET-1) in the airways of NSIP and FASSc patients.

METHODS

Ten NSIP (6 males, age 57 +/- 2 years) and 15 FASSc (8 males, age 55 +/- 4 years) patients were recruited along with 10 normal subjects (4 male, age 52 +/- 2 years). Vitronectin and ET-1 concentrations were measured in their breath condensate, using a specific enzyme immunoassay.

RESULTS

Higher levels of vitronectin and ET-1 were observed in NSIP and FASSc patients [median 92.8 (91.7-93.9) microg/ml; median 8.3 (7.9-9.3) pg/ml] than in control subjects [median 80.3 (89.3-91.4) microg/ml; p < 0.01; median 5.3 (4.9-5.9) pg/ml, p < 0.0001]. We also found increased concentrations of vitronectin in patients with clinical deterioration compared to those remaining stable and in ex-smokers compared to non-smokers and, increased vitronectin and ET-1 in patients treated with steroids compared to untreated patients.

CONCLUSION

These findings justify further studies of vitronectin and ET-1 levels in exhaled breath condensate, as a means of monitoring activity and predicting progression of pulmonary fibrosis.

Single-cell analysis: a novel approach to tumour necrosis factor-alpha synthesis and secretion in sarcoidosis

Tumour necrosis factor (TNF)-alpha is thought to be a key early cytokine in the pathogenesis of sarcoidosis, despite conflicting data. Largely the product of mononuclear phagocyte activation, it is unclear whether TNF-alpha production at disease sites is a feature of all mononuclear phagocytes that accumulate there or whether it is secreted by a subset of these cells. Using the reverse haemolytic plaque assay, the aims of this study were to determine if the upregulation of TNF-alpha could be confirmed and to investigate whether this was monocyte or macrophage specific. The reverse haemolytic plaque assay allows the measurement of cytokine production at a single cell level. A greater number of alveolar macrophages produced TNF-alpha compared to autologous monocytes in sarcoidosis but not in controls and, based on cell size, it was confirmed that this was the product of more mature macrophages and that the secretion of TNF-alpha by monocytes and macrophages was heterogeneous: not all monocytes and macrophages secrete TNF-alpha. No differences in the average levels of TNF-alpha secretion by peripheral blood monocytes or alveolar macrophages were observed. This study has demonstrated that a subset of mononuclear phagocytes, mature macrophages, are responsible for tumour necrosis factor secretion and this could have implications for targeted management in sarcoidosis in the future.

Extended genetic alterations in a patient with pulmonary sarcoidosis, a benign disease

BACKGROUND

Genetic alterations at the microsatellite level have been detected in various human malignant tissues, but have also been found in chronically inflamed tissues. Sarcoidosis is a benign disease of unknown etiology characterized by chronic inflammation, which may be associated with an increased incidence of developing malignancy.

METHODS

We examined the microsatellite alterations in a sputum cytological specimen of a patient with sarcoidosis. The DNA electrophoretic pattern of sputum was compared with that of the peripheral blood. Thirty-two microsatellite markers located at chromosomes 2p, 3p, 8p, 9p, 9q, 17p, 17q were used to reveal genetic alterations.

RESULTS

Loss of heterozygosity (LOH) was detected in eleven markers in loci 2p, 9p, 9q and 17q. LOH was observed in all four markers spanning the chromosomal arm 17q11.2-q21, suggesting a potential chromosomal deletion.

CONCLUSION

The observation of LOH in all four markers spanning the chromosomal arm 17q11.2-q21 may suggest a potential for malignancy development in this patient, or may be linked to the aetiopathogenesis of sarcoidosis. Further microsatellite fine mapping and clinical follow up of this patient are needed to clarify this.

Human leukocyte antigen-DRB1 position 11 residues are a common protective marker for sarcoidosis

Genetic factors, in particular human leukocyte antigens (HLAs) are important determinants of susceptibility to sarcoidosis, a chronic granulomatous disease of undetermined etiology. To clarify the role of HLA in sarcoidosis we determined HLA-DR and -DQ alleles in case-control samples from three European populations (United Kingdom, Czech, and Polish) and compared these results with those published for three additional populations (Italian, Japanese, and Scandinavian) to determine whether the HLA-DR and/or -DQ alleles act as ethnic-dependent, or ethnic-independent modifiers of disease risk. Although variations were apparent in the alleles associated with susceptibility, reductions in the frequency of alleles associated with protection were remarkably consistent in the six populations. Previously detected associations between single-nucleotide polymorphisms at the TAP2 locus and sarcoidosis were shown to be due to linkage disequilibrium with the HLA-DR locus. The protective HLA-DR alleles, which encode the DR1 and DR4 antigens, were found to share characteristic small hydrophobic residues at position 11, which were replaced by small hydrophilic residues in the remaining, nonprotective, HLA-DR alleles. This residue position is within a pocket of the HLA-DR complex antigen binding groove (designated P6), where it is the only variable amino acid and therefore determines the peptide binding preferences of this pocket. A highly significant reduction in the frequency of individuals carrying HLA-DR alleles with a hydrophobic residue at position 11 was observed in the sarcoidosis cases in the three populations we examined. This suggests this HLA-DR residue is an important protective marker in sarcoidosis.

Alveolar macrophages and T cells from sarcoid, but not normal lung, are permissive to adenovirus infection and allow analysis of NF-kappa b-dependent signaling pathways

Adenovirus (Adv)-mediated gene transfer requires efficient infection of target cells. The objective of this study was to establish whether alveolar macrophages (AM) and T cells (AT) from sarcoid patients were permissive to infection with Adv vectors and if this property could be used to investigate cytokine gene regulation. Sarcoid and normal bronchoalveolar lavage (BAL) specimens infected with Adv vectors expressing either beta-galactosidase or a green fluorescent protein were analyzed for transgene expression by fluorescence-activated cell sorter (FACS) and direct immunofluorescence, respectively. Expression of surface antigens previously associated with Adv infection, the coxsackie/adenovirus receptor (CAR), alpha v beta 3, and alpha v beta 5 integrins, was also assessed using FACS analysis. Sarcoid AM and AT were found to efficiently express Adv transgenes, unlike AM from normal volunteers, peripheral blood monocytes, and peripheral blood T cells. Cells permissive to Adv infection expressed the CAR and alpha v beta 5 integrin (also alpha v beta 3 integrin for AM). The data indicate that the upregulation of Adv receptors and the ability to infect sarcoid AM and AT are related to the inflammatory environment within the lung. Having demonstrated efficient Adv-mediated transgene delivery to sarcoid AM and AT, a construct encoding porcine I kappa B alpha was then used to investigate the requirement for nuclear factor (NF)-kappa B in the regulation of cytokine gene expression in pulmonary sarcoidosis. Overexpression of I kappa B alpha in sarcoid BAL specimens indicated that tumor necrosis factor-alpha and interleukin (IL)-6 production by AM and interferon (IFN)-gamma production by AT is NF-kappa B dependent, whereas IL-4 production by AT is NF-kappa B independent. This is the first occasion that the requirement for NF-kappa B in IFN-gamma gene expression within primary human T cells has been demonstrated. The results of this study have implications for the future investigation of molecular pathways in inflammatory lung disease.

Ace gene I/D polymorphism and sarcoidosis pulmonary disease severity

Previous studies of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene in sarcoidosis have revealed both ethnic heterogeneity of I/D frequencies and controversy surrounding the association between the polymorphism and severity of disease. The objective of this study was, therefore, to clarify the role of the ACE I/D polymorphism in (1) disease susceptibility, (2) pulmonary disease severity (with particular reference to pulmonary fibrosis), and (3) pulmonary disease progression, in two distinct European sarcoidosis populations. Standard chest radiographic staging was performed on 118 UK and 56 Czech white patients with sarcoidosis at 2 yr from presentation. Pulmonary function data were analyzed, and patients were then categorized according to disease severity. A PCR-SSP assay was used to determine the ACE I/D genotype of each patient studied. The I/D allele frequencies from these patients were compared with frequencies from ethnically matched UK (n = 386) and Czech (n = 179) control subjects using a chi-square contingency table. No significant differences were seen in the distribution of the ACE I/D genotypes, allele frequencies or phenotype frequencies. Furthermore, no association was found between the ACE I/D polymorphism and pulmonary disease severity, fibrosis, and progression. We conclude that the ACE I/D polymorphism has no role in sarcoidosis susceptibility in European whites and that it is not a regulatory variant in this disease.

Analysis of tumor necrosis factor-alpha, lymphotoxin-alpha, tumor necrosis factor receptor II, and interleukin-6 polymorphisms in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterized by chronic inflammation that is associated with structural damage of the lung and fibrosis. Although the etiology of IPF is unknown, it is likely to involve an interaction between environmental and multiple genetic components. Animal models of pulmonary fibrosis have shown that proinflammatory mediators are critical at both the inflammatory and fibrotic stages of the disease. Genetic variants exist in genes encoding proinflammatory mediators, as well as in genes encoding their receptors, which makes these genes candidates for the pathogenesis of IPF. In the present study, we examined 12 biallelic polymorphisms in the genes for tumor necrosis factor (TNF)-alpha (+488[G/A], -238[G/A], -308[G/A]), lymphotoxin (LT)-alpha (+720[C/A], +365[C/G], and +249[A/G], determining haplotypes LT-alpha1 to LT-alpha4), tumor necrosis factor-receptor 2 (TNF-RII) (gb:M32315: 676[T/G], 1663[A/G], 1668[T/G], 1690[C/T]), and interleukin- (IL)-6 (promoter -174[G/C], intron 4[A/G]). We also examined the haplotypes determined by the three biallelic polymorphisms in each of the TNF-alpha and LT-alpha genes. As compared with a normal control population, the IPF group showed no significant deviations in genotype, allele, or haplotype frequencies. Surprisingly, in the IPF population, but not in the control population, an increased frequency of cocarriage of the IL-6 intron 4G and the TNF-RII 1690C alleles was observed, despite the location of the two genes on different chromosomes. Moreover, using impairment of carbon monoxide transfer (DL(CO)) adjusted for duration of dyspnea as a marker of rapidity of disease progression, we found that the IL-6 intron 4GG genotype was the only genotype independently associated with lower DL(CO) levels. These findings, if independently confirmed, will be the first to suggest that disease progression in IPF may be linked to a particular genetic marker or to functional polymorphisms in other genes near that marker.

Distribution of novel polymorphisms of the interleukin-8 and CXC receptor 1 and 2 genes in systemic sclerosis and cryptogenic fibrosing alveolitis

OBJECTIVE

To search for single-nucleotide polymorphisms in the interleukin-8 (IL-8) and IL-8 receptor CXCR-1 and CXCR-2 genes, and to compare their distribution among patients with systemic sclerosis (SSc) with fibrosing alveolitis (FASSc) or without fibrosing alveolitis (NFASSc), or patients with cryptogenic fibrosing alveolitis (CFA), and normal healthy subjects.

METHODS

Fifty control subjects were screened for potential polymorphisms by using polymerase chain reaction in association with sequence-specific primers incorporating mismatches at the 3' end. The novel polymorphisms were subsequently examined in British Caucasian subjects, including 194 healthy controls, 71 patients with CFA, and 128 patients with SSc who were further subdivided into 78 FASSc patients and 50 NFASSc patients.

RESULTS

Three novel biallelic polymorphisms were identified in the IL-8 gene (all in noncoding areas of the gene), 1 was found in the CXCR-1 gene (resulting in a conservative amino acid change), and 3 were observed in the CXCR-2 gene, of which the first resulted in a silent codon change and the others were in the 3' untranslated area of exon 3. Compared with controls, a significant increase in the frequency of the CXCR-2 +785 CC homozygote and of the CXCR-2 +1208 TT homozygote was found in the SSc patients (37% versus 22% [P = 0.01] and 33% versus 17% [P = 0.003], respectively). A subgroup analysis revealed this association to be significant both in the FASSc patients and in the NFASSc patients.

CONCLUSION

This report describes an association between SSc and 2 polymorphisms occurring close to each other in the CXCR-2 gene. This finding and its functional significance need to be confirmed and analyzed in future studies.

Distribution of novel polymorphisms of the interleukin-8 and CXC receptor 1 and 2 genes in systemic sclerosis and cryptogenic fibrosing alveolitis

OBJECTIVE

To search for single-nucleotide polymorphisms in the interleukin-8 (IL-8) and IL-8 receptor CXCR-1 and CXCR-2 genes, and to compare their distribution among patients with systemic sclerosis (SSc) with fibrosing alveolitis (FASSc) or without fibrosing alveolitis (NFASSc), or patients with cryptogenic fibrosing alveolitis (CFA), and normal healthy subjects.

METHODS

Fifty control subjects were screened for potential polymorphisms by using polymerase chain reaction in association with sequence-specific primers incorporating mismatches at the 3' end. The novel polymorphisms were subsequently examined in British Caucasian subjects, including 194 healthy controls, 71 patients with CFA, and 128 patients with SSc who were further subdivided into 78 FASSc patients and 50 NFASSc patients.

RESULTS

Three novel biallelic polymorphisms were identified in the IL-8 gene (all in noncoding areas of the gene), 1 was found in the CXCR-1 gene (resulting in a conservative amino acid change), and 3 were observed in the CXCR-2 gene, of which the first resulted in a silent codon change and the others were in the 3' untranslated area of exon 3. Compared with controls, a significant increase in the frequency of the CXCR-2 +785 CC homozygote and of the CXCR-2 +1208 TT homozygote was found in the SSc patients (37% versus 22% [P = 0.01] and 33% versus 17% [P = 0.003], respectively). A subgroup analysis revealed this association to be significant both in the FASSc patients and in the NFASSc patients.

CONCLUSION

This report describes an association between SSc and 2 polymorphisms occurring close to each other in the CXCR-2 gene. This finding and its functional significance need to be confirmed and analyzed in future studies.

The effect of lung biopsy on lung function in diffuse lung disease

The aim of this study was to investigate the effect on lung function of lung biopsy used in the diagnosis of diffuse lung disease carried out by an open procedure or by video-assisted thoracoscopy. One hundred and sixteen patients with diffuse lung disease who attended the Royal Brompton Hospital were studied retrospectively. Thirty five patients underwent open lung biopsy, and 33 video-assisted thoracoscopic biopsy and 48 had their diagnosis made without biopsy. All patients underwent lung function tests before and after surgery, or at an interval of 3-6 months in those who did not undergo biopsy. No significant differences were found in changes in lung function between those who had and had not undergone biopsy, and the proportions of patients whose lung function improved or deteriorated were similar. Lung biopsy by an open procedure or by video-assisted thoracoscopy did not differ in its effects on lung function. The results for older patients, those with severe disease and those with fibrosing alveolitis were the same as for the whole group. Open lung biopsy for the diagnosis of diffuse lung disease does not deleteriously affect lung function whether carried out by an open or a minimally invasive procedure.

Identification of four novel interleukin-13 gene polymorphisms

The development of allergic asthma is thought to involve environmental and inherited genetic components and has pathophysiological features reflecting in part the activity of T cell cytokines. Interleukin-13, a product primarily of activated lymphocytes, is considered to be a critical effector molecule in allergic airway response and has been found to be overexpressed in the airways of patients with asthma. The IL-13 gene is located on chromosome 5q31, one of the major loci to be linked to asthma susceptibility, and amongst a cluster of genes which dominate the immunopathology of allergic disease. Recently, an IL-13 promoter polymorphism was found to be associated with allergic asthma. In the present study we report the identification of four novel biallelic polymorphisms in the IL-13 gene, two intronic and two exonic, one of which results in a basic to hydrophilic amino acid change. We characterised the frequencies of these four biallelic polymorphisms and the frequencies of the haplotypes, resulting from the combination of these four biallelic polymorphisms, in a population of 196 UK Caucasoid healthy individuals.