Trends in 3D models of inflammatory bowel disease

Inflammatory bowel disease (IBD) encompasses a set of chronic inflammatory conditions, namely Crohn's disease and ulcerative colitis. Despite all advances in the management of IBD, a definitive cure is not available, largely due to a lack of a holistic understanding of its etiology and pathophysiology. Several in vitro, in vivo, and ex vivo models have been developed over the past few decades in order to abbreviate remaining gaps. The establishment of reliable and predictable in vitro intestinal inflammation models may indeed provide valuable tools to expedite and validate the development of therapies for IBD. Three-dimensional (3D) models provide a more accurate representation of the different layers of the intestine, contributing to a stronger impact on drug screening and research on intestinal inflammation, and bridging the gap between in vitro and in vivo research. This work provides a critical overview on the state-of-the-art on existing 3D models of intestinal inflammation and discusses the remaining challenges, providing insights on possible pathways towards achieving IBD mimetic models. We also address some of the main challenges faced by implementing cell culture models in IBD research while bearing in mind clinical translational aspects.

Unsupervised clustering to differentiate rheumatoid arthritis patients based on proteomic signatures

OBJECTIVE

Patients with rheumatoid arthritis (RA) have different presentations and prognoses. Cluster analysis based on proteomic signatures creates independent phenogroups of patients with different pathophysiological backgrounds. We aimed to identify distinct pathophysiological clusters of RA patients based on circulating proteomic biomarkers.

METHOD

This was a cohort study including 399 RA patients. Clustering was performed on 94 circulating proteins (92 CVDII Olink®, high-sensitivity troponin T, and C-reactive protein). Unsupervised clustering was performed using a partitioning cluster algorithm.

RESULTS

The clustering algorithm identified two distinct clusters: cluster 1 (n = 223) and cluster 2 (n = 176). Compared with cluster 1, cluster 2 included older patients with a higher burden of comorbidities (cardiovascular and RA related), more erosive and longer RA duration, more dyspnoea and fatigue, walking a shorter distance in the Six-Minute Walk Test, with more severe diastolic dysfunction, and a 4.5-fold higher risk of death or hospitalization for cardiovascular reasons. Tumour necrosis factor (TNF) receptor superfamily-related pathways were mainly responsible for the model's discriminative ability.

CONCLUSION

Using unsupervised cluster analysis based on proteomic phenotypes, we identified two clusters of RA patients with distinct biomarkers profiles, clinical characteristics, and different outcomes that could reflect different pathophysiological backgrounds. TNF receptor superfamily-related proteins may be used to distinguish subgroups.

Mucus-producing 3D cell culture models

In vitro cell-based models have been used for a long time since they are normally easily obtained and have an advantageous cost-benefit. Besides, they can serve a variety of ends, from studying drug absorption and metabolism to disease modeling. However, some in vitro models are too simplistic, not accurately representing the living tissues. It has been shown, mainly in the last years, that fully mimicking a tissue composition and architecture can be paramount for cellular behavior and, consequently, for the outcomes of the studies using such models. Because of this, 3D in vitro cell models have been gaining much attention, since they are able to better replicate the in vivo environment. In this review we focus on 3D models that contain mucus-producing cells, as mucus can play a pivotal role in drug absorption. Being frequently overlooked, this viscous fluid can have an impact on drug delivery. Thus, the aim of this review is to understand to which extent can mucus affect mucosal drug delivery and to provide a state-of-the-art report on the existing 3D cell-based mucus models.

Off-pump versus on-pump coronary artery bypass grafting: a propensity score-matching analysis of safety and long-term results

Background

The role and the indications for using off-pump coronary artery bypass surgery (OPCAB), instead of the traditional on-pump (ONCAB), is still to be addressed.

Aim

To describe our centre experience and to compare 15-years survival and early safety outcomes between OPCAB and ONCAB.

Methods

Single-centre retrospective cohort including 9-years of isolated first CABG (2005–2013). Multi-vessel disease with at least 2 surgical grafts patients were considered and the first 50 surgeries of each surgeon with each technique were excluded to account for the learning curve effect. Emergent surgeries and on-pump beating heart procedures were also excluded. A propensity-score matching (PSM) analysis was performed to balance groups and both survival and early outcomes comparison was done within the matched cohort using Kaplan-Meier or Cox stratified and paired tests, respectively. The median follow-up was 9 years, maximum 15 years.

Results

From 3012 multi-vessel patients with at least 2 surgical grafts, 2503 were included at the main analysis: 1487 ONCAB and 1016 OPCAB. ONCAB patients presented more frequently 3-vessels disease and left ventricular dysfunction, but received similar number of grafts than OPCAB, who in turn, received more frequently multiple arterial grafts. The surgical completeness of revascularization (CR) was similar, but hybrid procedures were more frequent in OPCAB raising CR rate in this group. After PSM (646 pairs), both groups were similar regarding pre and peri-operative characteristics. The long-term survival was similar (HR stratified by pair: 1.02 (0.81–1.30), but OPCAB evidenced benefits at early term results including bleeding, postoperative atrial fibrillation and stroke incidence.

Conclusion

At our centre, OPCAB performed by experienced surgeons provides rates of complete revascularization and long-term survival similar to ONCAB. In-hospital results favoured OPCAB.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Universidade do Porto/FMUP; Social European Fund; FCT-Fundação para a Ciência e a Tecnologia

A meta-analysis of randomized controlled studies comparing off-pump vs on-pump CABG in the elderly

Background

The increasing demand for coronary revascularization in the elderly has raised the interest in off-pump coronary artery bypass graft (CABG) as an option in these high-risk patients.

Purpose

We sought to investigate the differences between off-pump CABG (OPCAB) and on-pump CABG (ONCAB), among patients older than 60, in short and mid-term results throughout a meta-analysis of randomized clinical trials (RCTs).

Methods

A literature search was conducted using MEDLINE, ISI Web of Science and Cochrane Library (1960–2020). RCTs reporting mortality outcomes of OPCAB vs ONCAB within elderly patients (as prespecified or secondary analysis) were included. Data on myocardial infarction, stroke, repeat revascularization, renal failure and composite endpoints after CABG were also collected. Hazard ratio (HR) and variance for follow-up outcomes and frequencies or odds ratio (OR) for early endpoints were collected. Random effect models were used to compute statistical combined measures and 95% confidence intervals (CI).

Results

Seven RCTs encompassing a total of 6,609 patients were included (3,303 OPCAB and 3,306 ONCAB, 50% were men). Five trials reported mortality during follow-up (6 months (2 studies) to 5 years). There were no significant differences on mid-term mortality (pooled HR: 1.02, 95% CI: 0.88–1.17, p=0.82) and composite endpoint incidence (4 studies pooled HR: 0.98, 95% CI: 0.88–1.09, p=0.73) between OPCAB and ONCAB. At 30-days, no differences between groups were noted in mortality (5 studies pooled OR: 0.90, 95% CI: 0.62–1.31, p=0.59), early myocardial infarction (5 studies pooled OR: 0.95, 95% CI: 0.60–1.51, p=0.82) and renal complications (3 studies pooled OR: 0.74, 95% CI: 0.50–1.11, p=0.14). The need for early repeat revascularization was significantly higher in OPCAB (2 studies pooled OR: 2.58, 95% CI: 1.16–5.75, p=0.02), with higher percentage of incomplete revascularization among OPCAB in both trials included in this pooled result (34% in OPCAB vs 29% in ONCAB, p<0.01). However, OPCAB showed a tendency for lower risk of early stroke (6 studies pooled OR: 0.70, 95% CI: 0.48–1.03, p=0.07).

Conclusions

Pooling data from RCTs in elderly patients showed that OPCAB and ONCAB provide similar mid-term results. However, OPCAB was associated with a higher risk of early repeat revascularization and there was a trend for reduced early stroke risk. Further randomized studies, specifically designed to include elderly patients, are needed to establish the better CABG strategy.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Universidade do Porto/FMUP and FSE-Social European Fund; Fundação para a Ciência e Tecnologia Early and Mid-term Results

P4643Pulmonary hypertension incidence is higher than systemic arterial hypertension in children after aortic coarctation repair

Introduction

Coarctation of the aorta (CoA) is characterized by diffuse arteriopathy which can persist to upward of the aortic isthmus, even after successful surgical correction. This arteriopathy can also occur in the pulmonary vasculature, leading to pulmonary hypertension (PH), a strong risk factor of poor prognosis in CoA population.

Purpose

The purpose of this study was to determine the incidence of systemic and pulmonary hypertension in a CoA paediatric population after surgical repair, as well as the impact of PH in right ventricular function.

Methods

This cross-sectional study included children after successful surgical repair of the CoA in a tertiary centre [1996, 2009] up to the first year of age. Children with other cardiac structural lesions or recoarctation were excluded. Systemic arterial hypertension was defined as blood pressure in the 95th percentile or higher. PH was considered if the estimated pulmonary systolic arterial pressure (PSAP) was higher than 30mmHg. Pulse wave velocity, ambulatory 24 hours blood pressure monitoring, echocardiographic assessment of right ventricle (RV) and blood tests were performed 11±4 years after surgical procedure. Echocardiographic variables were normalized and evaluated by z-scores. One sample t test or sign test was used to estimate the deviation of measured/observed values from the normality/expected values (defined by z-score=0).

Results

We included 38 children with a mean age of 12±4 years (63% male). Late arterial hypertension was diagnosed in 29% of the children and PH incidence was 68% with a mean PSAP of 37±5mmHg. The mean of A' wave (z-score: 0.34±0.93, p=0.030) and median of E/E' ratio (z-score: 0.46 [−1.32; 3.68], p=0.004) z-scores were increased comparing with expected normal values in paediatric population. Moreover, E' wave (z-score: −0.35±0.98, p=0.034) and RV index of myocardial performance (z-score: −0.20±0.41, p=0.006) were decreased. Regarding RV systolic function, TAPSE z-score was significantly increased (z-score: 2.06±2.33, p<0.001), being outside the z-score normal range.

Conclusion

Children submitted to CoA surgical repair before the first year of life showed a higher PH incidence than late systemic hypertension occurrence. Also, they already present with significant RV functional abnormalities when compared to the normal paediatric population. These abnormalities can underlie pulmonary vascular remodelling after left ventricular pressure overload in CoA population that seems irreversible after pressure overload relief.

Acknowledgement/Funding

AFF are supported by FCT (SFRH/BD/138925/2018)

Establishment of 2D Cell Cultures Derived From 3D MCF-7 Spheroids Displaying a Doxorubicin Resistant Profile

In vitro 3D cancer spheroids generally exhibit a drug resistance profile similar to that found in solid tumors. Due to this property, these models are an appealing for anticancer compounds screening. Nevertheless, the techniques and methods aimed for drug discovery are mostly standardized for cells cultured in 2D. The development of 2D cell culture models displaying a drug resistant profile is required to mimic the in vivo tumors, while the equipment, techniques, and methodologies established for conventional 2D cell cultures can continue to be employed in compound screening. In this work, the response of 3D-derived MCF-7 cells subsequently cultured in 2D in medium supplemented with glutathione (GSH) (antioxidant agent found in high levels in breast cancer tissues and a promoter of cancer cells resistance) to Doxorubicin (DOX) is evaluated. These cells demonstrated a resistance toward DOX closer to that displayed by 3D spheroids, which is higher than that exhibited by standard 2D cell cultures. In fact, the 50% inhibitory concentration (IC₅₀ ) of DOX in 3D-derived MCF-7 cell cultures supplemented with GSH is about eight-times higher than that obtained for conventional 2D cell cultures (cultured without GSH), and is only about two-times lower than that attained for 3D MCF-7 spheroids (cultured without GSH). Further investigation revealed that this improved resistance of 3D-derived MCF-7 cells may result from their increased P-glycoprotein (P-gp) activity and reduced production of intracellular reactive oxygen species (ROS).

Probing beer aging chemistry by nuclear magnetic resonance and multivariate analysis

This paper describes the use of nuclear magnetic resonance (NMR) spectroscopy, in tandem with multivariate analysis (MVA), for monitoring the chemical changes occurring in a lager beer exposed to forced aging (at 45°C for up to 18 days). To evaluate the resulting compositional variations, both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and a clear aging trend was observed. Inspection of PLS-DA loadings and peak integration enabled the changing compounds to be identified, revealing the importance of well known markers such as 5-hydroxymethylfurfural (5-HMF) as well as a range of other relevant compounds: amino acids, higher alcohols, organic acids, dextrins and some still unassigned spin systems. In addition, the multivariate analysis method of 2D correlation analysis was applied to the NMR data enabling the relevant compound variations to be confirmed and inter-compound correlations to be assessed, some reflecting common metabolic/chemical pathways and, therefore, offering improved insight into the chemical aspects of beer aging.

Profiling allergic asthma volatile metabolic patterns using a headspace-solid phase microextraction/gas chromatography based methodology

Allergic asthma represents an important public health issue with significant growth over the years, especially in the paediatric population. Exhaled breath is a non-invasive, easily performed and rapid method for obtaining samples from the lower respiratory tract. In the present manuscript, the metabolic volatile profiles of allergic asthma and control children were evaluated by headspace solid-phase microextraction combined with gas chromatography-quadrupole mass spectrometry (HS-SPME/GC-qMS). The lack of studies in breath of allergic asthmatic children by HS-SPME led to the development of an experimental design to optimize SPME parameters. To fulfil this objective, three important HS-SPME experimental parameters that influence the extraction efficiency, namely fibre coating, temperature and time extractions were considered. The selected conditions that promoted higher extraction efficiency corresponding to the higher GC peak areas and number of compounds were: DVB/CAR/PDMS coating fibre, 22 °C and 60 min as the extraction temperature and time, respectively. The suitability of two containers, 1L Tedlar® bags and BIOVOC®, for breath collection and intra-individual variability were also investigated. The developed methodology was then applied to the analysis of children exhaled breath with allergic asthma (35), from which 13 had also allergic rhinitis, and healthy control children (15), allowing to identify 44 volatiles distributed over the chemical families of alkanes (linear and ramified) ketones, aromatic hydrocarbons, aldehydes, acids, among others. Multivariate studies were performed by Partial Least Squares-Discriminant Analysis (PLS-DA) using a set of 28 selected metabolites and discrimination between allergic asthma and control children was attained with a classification rate of 88%. The allergic asthma paediatric population was characterized mainly by the compounds linked to oxidative stress, such as alkanes and aldehydes. Furthermore, more detailed information was achieved combining the volatile metabolic data, suggested by PLS-DA model, and clinical data.

Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods

The organic acids present in beer provide important information on the product's quality and history, determining organoleptic properties and being useful indicators of fermentation performance. NMR spectroscopy may be used for rapid quantification of organic acids in beer and different NMR-based methodologies are hereby compared for the six main acids found in beer (acetic, citric, lactic, malic, pyruvic and succinic). The use of partial least squares (PLS) regression enables faster quantification, compared to traditional integration methods, and the performance of PLS models built using different reference methods (capillary electrophoresis (CE), both with direct and indirect UV detection, and enzymatic essays) was investigated. The best multivariate models were obtained using CE/indirect detection and enzymatic essays as reference and their response was compared with NMR integration, either using an internal reference or an electrical reference signal (Electronic REference To access In vivo Concentrations, ERETIC). NMR integration results generally agree with those obtained by PLS, with some overestimation for malic and pyruvic acids, probably due to peak overlap and subsequent integral errors, and an apparent relative underestimation for citric acid. Overall, these results make the PLS-NMR method an interesting choice for organic acid quantification in beer.

Improving the detection of significant factors using ANOVA-PCA by selective reduction of residual variability

Selective elimination of residual error can be used when applying Harrington's ANOVA-PCA in order to improve the capabilities of the method. ANOVA-PCA is sometimes unable to discriminate between levels of a factor when sources of high residual variability are present. In some cases this variability is not random, possesses some structure and is large enough to be responsible for the first principal components calculated by the PCA step in the ANOVA-PCA. This fact sometimes makes it impossible for the interesting variance to be in the first two PCA components. By using the proposed selective residuals elimination procedure, one may improve the ability of the method to detect significant factors as well as have an understanding of the different kinds of residual variance present in the data. Two datasets are used to show how the method is used in order to iteratively detect variance associated with the factors even when it is not initially visible. A permutation method is used to confirm that the observed significance of the factors was not accidental.

Variability of cork from Portuguese Quercus suber studied by solid-state (13)C-NMR and FTIR spectroscopies

A new approach is presented for the study of the variability of Portuguese reproduction cork using solid-state (13)C-NMR spectroscopy and photoacoustic (PAS) FTIR (FTIR-PAS) spectroscopy combined with chemometrics. Cork samples were collected from 12 different geographical sites, and their (13)C-cross-polarization with magic angle spinning (CP/MAS) and FTIR spectra were registered. A large spectral variability among the cork samples was detected by principal component analysis and found to relate to the suberin and carbohydrate contents. This variability was independent of the sample geographical origin but significantly dependent on the cork quality, thus enabling the distinction of cork samples according to the latter property. The suberin content of the cork samples was predicted using multivariate regression models based on the (13)C-NMR and FTIR spectra of the samples as reported previously. Finally, the relationship between the variability of the (13)C-CP/MAS spectra with that of the FTIR-PAS spectra was studied by outer product analysis. This type of multivariate analysis enabled a clear correlation to be established between the peaks assigned to suberin and carbohydrate in the FTIR spectrum and those appearing in the (13)C-CP/MAS spectra.

Quantitation of aliphatic suberin in Quercus suber L. cork by FTIR spectroscopy and solid-state (13)C-NMR spectroscopy

This work determined that the percentage of suberin in cork may be found by solid-state (13)C cross polarization/magic angle spinning (CP/MAS) NMR spectroscopy and by FTIR with photoacoustic detection (FTIR-PAS) spectroscopy. A linear relationship is found between the suberin content measured through CP/MAS spectral areas and that measured gravimetrically. Furthermore, application of a partial least squares (PLS1) regression model to the NMR and gravimetric data sets clearly correlates the two sets, enabling suberin quantification with 90% precision. Suberin quantitation by FTIR-PAS spectroscopy is also achieved by a PLS1 regression model, giving 90% accurate estimates of the percentage of suberin in cork. Therefore, (13)C-CP/MAS NMR and FTIR-PAS proved to be useful and accurate noninvasive techniques to quantify suberin in cork, thus avoiding the traditional time consuming and destructive chemical methods.

[Comparative analysis of conventional dental floss and alternative materials]

The interproximal plaque-removing effect of three different materials (classic dental floss, rafia floss and indian floss) was tested in a group of 80 males (18 years-old). After two weeks all the materials had the same efficacy in removing the bacterial plaque, with significant reduction in interproximal plaque index. According to an opinion inquiry the rafia floss was the most comfortable material to use and has the lowest cost as well.