Charting the Path: Navigating Embryonic Development to Potentially Safeguard against Congenital Heart Defects.

Congenital heart diseases (CHDs) are structural or functional defects present at birth due to improper heart development. Current therapeutic approaches to treating severe CHDs are primarily palliative surgical interventions during the peri- or prenatal stages, when the heart has fully developed from faulty embryogenesis. However, earlier interventions during embryonic development have the potential for better outcomes, as demonstrated by fetal cardiac interventions performed in utero, which have shown improved neonatal and prenatal survival rates, as well as reduced lifelong morbidity. Extensive research on heart development has identified key steps, cellular players, and the intricate network of signaling pathways and transcription factors governing cardiogenesis. Additionally, some reports have indicated that certain adverse genetic and environmental conditions leading to heart malformations and embryonic death may be amendable through the activation of alternative mechanisms. This review first highlights key molecular and cellular processes involved in heart development. Subsequently, it explores the potential for future therapeutic strategies, targeting early embryonic stages, to prevent CHDs, through the delivery of biomolecules or exosomes to compensate for faulty cardiogenic mechanisms. Implementing such non-surgical interventions during early gestation may offer a prophylactic approach toward reducing the occurrence and severity of CHDs.

Human Stem Cells for Cardiac Disease Modeling and Preclinical and Clinical Applications-Are We on the Road to Success?

Cardiovascular diseases (CVDs) are pointed out by the World Health Organization (WHO) as the leading cause of death, contributing to a significant and growing global health and economic burden. Despite advancements in clinical approaches, there is a critical need for innovative cardiovascular treatments to improve patient outcomes. Therapies based on adult stem cells (ASCs) and embryonic stem cells (ESCs) have emerged as promising strategies to regenerate damaged cardiac tissue and restore cardiac function. Moreover, the generation of human induced pluripotent stem cells (iPSCs) from somatic cells has opened new avenues for disease modeling, drug discovery, and regenerative medicine applications, with fewer ethical concerns than those associated with ESCs. Herein, we provide a state-of-the-art review on the application of human pluripotent stem cells in CVD research and clinics. We describe the types and sources of stem cells that have been tested in preclinical and clinical trials for the treatment of CVDs as well as the applications of pluripotent stem-cell-derived in vitro systems to mimic disease phenotypes. How human stem-cell-based in vitro systems can overcome the limitations of current toxicological studies is also discussed. Finally, the current state of clinical trials involving stem-cell-based approaches to treat CVDs are presented, and the strengths and weaknesses are critically discussed to assess whether researchers and clinicians are getting closer to success.

[Risk Factors for Delayed Discharge Due to Social Factors: A Retrospective Study]. / Factores de Risco para Alta Prorrogada por Motivos Sociais: Um Estudo Retrospectivo.

INTRODUCTION: The hospital setting faces a rate of bed occupation by patients whose discharge is limited by other factors apart from clinical needs. This urges the need for an early identification of the patients at risk of delayed discharge due to social factors in order to reduce expenses and to add value that converts itself into the patient health. The aim of this study was to identify the demographic and clinical factors that may be associated with delayed discharge. MATERIAL AND METHODS: Demographic and clinical comorbidity data on 582 patients of an internal medicine ward from a tertiary hospital center during the years 2018 and 2019 was analyzed. A binomial logistic regression model was used, adjusted for sex, age, and length of clinical stay, in order to identify potential risk factors associated with delayed discharge. RESULTS: A total of 473 patients admitted in the internal medicine ward throughout the two years of study were included. Ninety-four (19%) of these patients had their discharge delayed beyond their clinical needs; sixty-four (68%) of these were females. The most representative age was between 75 - 89 years old (45.7%). The characteristics that significantly differed between both non-delayed and delayed discharge were female sex (OR 2.84, 95% CI 1.65 - 4.90, p-value < 0.05), prolonged clinical stay (OR 2.64, 95% CI 1.60 - 4.937, p-value < 0.05) and diabetes mellitus (OR 1.87, 95% CI 1.08 - 3.23, p-value < 0.05). Besides these, the presence of heart failure (OR 0.52, 95% CI 0.27 - 0.99, p-value < 0.05) and chronic kidney disease (OR 0.34, 95% CI 0.14 - 0.86, p-value < 0.05) were associated with a lower risk of delayed discharge. CONCLUSION: Female sex, a prolonged clinical stay and diabetes mellitus were associated with a higher risk of delayed discharge, while heart failure and chronic kidney disease were associated with a reduced risk. These findings create a basis for a possible future multicentre study aimed at creating a clinical prediction rule to stratify the risk of delayed hospital discharge in the Portuguese population.

Introdução: Os hospitais deparam-se com uma percentagem das suas camas ocupadas por doentes cuja alta hospitalar está limitada não pela alta clínica, mas por outros fatores. Cria-se a necessidade da identificação precoce dos indivíduos que estão em risco de uma alta prorrogada por motivos sociais (internamentos sociais - IS), de forma a reduzir gastos e a acrescentar valor que se traduza em saúde dos utentes. O objetivo deste estudo foi identificar os fatores de risco demográficos e clínicos que condicionam risco de internamento social. Material e Métodos: Foram analisados 582 internamentos referentes a um serviço de Medicina Interna de hospital terciário nos anos de 2018 e 2019, e consideradas as características demográficas e comorbidades clínicas dos doentes. Foi feita uma regressão logística binominal ajustada ao sexo, idade e internamento clínico prolongado, para identificação de potenciais fatores de risco associados a alta prorrogada. Resultados: Foram incluídos neste estudo um total de 473 doentes admitido no serviço no período de dois anos em estudo. Noventa e quatro (19%) doentes tiveram a sua alta prorrogada, dos quais 64 (68%) eram do sexo feminino. As principais características estatisticamente significativas associadas a maior risco de prorrogação da alta foram o sexo feminino (OR 2,84, 95% IC 1,65 ­ 4,90, p-value < 0,05), o internamento clínico prolongado (OR 2,64, 95% IC 1,60 ­ 4,937, p-value < 0,05) e a diabetes mellitus (OR 1,87, 95% IC 1,08 ­ 3,23, p-value < 0,05); para além destes, a presença de insuficiência cardíaca (OR 0,52, 95% IC 0,27 ­ 0,99, p-value < 0,05) e de doença renal crónica (OR 0,34, 95% IC 0,14 ­ 0,86, p-value < 0,05) associaram-se a um risco inferior de prorrogação de alta. Conclusão: O sexo feminino, os internamentos clínicos prolongados e diabetes mellitus associaram-se a um maior risco de internamento social, enquanto a insuficiência cardíaca e a doença renal crónica se associaram a um risco inferior de IS. Estes achados servem de base de construção para um futuro estudo multicêntrico para criação de uma regra de predição clínica para estratificação do risco de internamento social na população portuguesa.

Necro-inflammatory activity grading in chronic viral hepatitis with three-dimensional multifrequency MR elastography.

The purpose of this study was to assess the diagnostic value of multifrequency MR elastography for grading necro-inflammation in the liver. Fifty participants with chronic hepatitis B or C were recruited for this institutional review board-approved study. Their liver was examined with multifrequency MR elastography. The storage, shear and loss moduli, and the damping ratio were measured at 56 Hz. The multifrequency wave dispersion coefficient of the shear modulus was calculated. The measurements were compared to reference markers of necro-inflammation and fibrosis with Spearman correlations and multiple regression analysis. Diagnostic accuracy was assessed. At multiple regression analysis, necro-inflammation was the only determinant of the multifrequency dispersion coefficient, whereas fibrosis was the only determinant of the storage, loss and shear moduli. The multifrequency dispersion coefficient had the largest AUC for necro-inflammatory activity A ≥ 2 [0.84 (0.71-0.93) vs. storage modulus AUC: 0.65 (0.50-0.79), p = 0.03], whereas the storage modulus had the largest AUC for fibrosis F ≥ 2 [AUC (95% confidence intervals) 0.91 (0.79-0.98)] and cirrhosis F4 [0.97 (0.88-1.00)]. The measurement of the multifrequency dispersion coefficient at three-dimensional MR elastography has the potential to grade liver necro-inflammation in patients with chronic vial hepatitis.

Molecular Magnetic Resonance Imaging of Fibrin Deposition in the Liver as an Indicator of Tissue Injury and Inflammation.

RATIONALE AND OBJECTIVES: Liver inflammation is associated with nonalcoholic steatohepatitis and other pathologies, but noninvasive methods to assess liver inflammation are limited. Inflammation causes endothelial disruption and leakage of plasma proteins into the interstitial space and can result in extravascular coagulation with fibrin deposition. Here we assess the feasibility of using the established fibrin-specific magnetic resonance probe EP-2104R for the noninvasive imaging of fibrin as a marker of liver inflammation. METHODS: Weekly 100 mg/kg diethylnitrosamine (DEN) dosing was used to generate liver fibrosis in male rats; control animals received vehicle. Magnetic resonance imaging at 1.5 T with EP-2104R, a matched non-fibrin-binding control linear peptide, or the collagen-specific probe EP-3533 was performed at 1 day or 7 days after the last DEN administration. Imaging data were compared with quantitative histological measures of fibrosis and inflammation. RESULTS: After 4 or 5 DEN administrations, the liver becomes moderately fibrotic, and fibrosis is the same if the animal is killed 1 day (Ishak score, 3.62 ± 0.31) or 7 days (Ishak score, 3.82 ± 0.25) after the last DEN dose, but inflammation is significantly higher at 1 day compared with 7 days after the last DEN dose (histological activity index from 0-4, 3.54 ± 0.14 vs 1.61 ± 0.16, respectively; P < 0.0001). Peak EP-2104R signal enhancement was significantly higher in animals imaged at 1 day post-DEN compared with 7 days post-DEN or control rats (29.0% ± 3.2% vs 22.4% ± 2.0% vs 17.0% ± 0.2%, respectively; P = 0.017). Signal enhancement with EP-2104R was significantly higher than control linear peptide at 1 day post-DEN but not at 7 days post-DEN indicating specific fibrin binding during the inflammatory phase. Collagen molecular magnetic resonance with EP-3533 showed equivalent T1 change when imaging rats 1 day or 7 days post-DEN, consistent with equivalent fibrosis. CONCLUSIONS: EP-2104R can specifically detect fibrin associated with inflammation in a rat model of liver inflammation and fibrosis.

Hepatic Fibrosis, Inflammation, and Steatosis: Influence on the MR Viscoelastic and Diffusion Parameters in Patients with Chronic Liver Disease.

Purpose To determine the relationship of liver fibrosis, inflammation, and steatosis with the magnetic resonance (MR) viscoelastic and diffusion parameters in patients with chronic liver disease and to compare the diagnostic accuracy of the imaging parameters in staging liver fibrosis. Materials and Methods Consecutive patients with chronic liver disease scheduled for liver biopsy were prospectively recruited from November 2010 to October 2012 for this institutional review board-approved study after they provided written informed consent. Sixty-eight patients underwent three-dimensional MR elastography and intravoxel incoherent motion diffusion-weighted MR imaging with a 1.5-T MR system. Fibrosis, inflammation, and steatosis were assessed with the METAVIR and steatosis, activity, and fibrosis (or SAF) scoring systems. Spearman correlation and multiple regression analyses were performed to determine the relationship between liver fibrosis, inflammation, steatosis, and alanine aminotransferase (ALT) levels and viscoelastic and diffusion parameters. The accuracy of three-dimensional MR elastography and diffusion-weighted MR imaging in the determination of fibrosis stage was assessed with Obuchowski measures. Results At multiple regression analysis, fibrosis was the only variable associated with viscoelastic parameters (ß = 0.6, P < .001, R2 = 0.33 for shear modulus; ß = 0.6, P < .001, R2 = 0.32 for elasticity). Fibrosis had a weaker independent association with the apparent diffusion coefficient (ß = -0.3, P = .02, R2 = 0.33) than did steatosis (ß = -0.5, P < .001, R2 = 0.33). Steatosis was the only factor independently associated with the pure diffusion coefficient (ß = -0.4, P = .002, R2 = 0.22). Inflammation and ALT level were not associated with the viscoelastic or diffusion parameters. The diagnostic accuracy of fibrosis staging was significantly higher when measuring the shear modulus rather than the apparent diffusion coefficient (Obuchowski measures, 0.82 ± 0.04 vs 0.30 ± 0.06; P < .001). Conclusion Fibrosis is independently associated with the MR viscoelastic parameters and is less associated with the diffusion parameters than is steatosis. These results and those of diagnostic accuracy suggest that MR elastography should be preferred over diffusion-weighted MR imaging in the staging of liver fibrosis. © RSNA, 2016.

Liver steatosis assessed by preoperative MRI: An independent risk factor for severe complications after major hepatic resection.

BACKGROUND: Steatosis assessed by histology is commonly considered to be a significant risk factor for liver surgery. MRI is considered as the new gold standard for noninvasive liver fat quantification. The purpose was to assess whether liver steatosis determined by preoperative MRI is an independent risk factor of complications after major liver resection. METHODS: All patients who underwent liver MRI before major liver resection in our institution between January 2001 and December 2011 were included in this retrospective study. The liver fat fraction (LFF) was assessed on in- and opposed-phase T1-weighted dual echo gradient echo MRI and steatosis was defined as a MRI LFF of ≥ 5%. The association between steatosis and postoperative complications (Clavien-Dindo classification, ascites > 500 mL at day 5, 50-50 criteria, fistula/collection, blood liver test alterations, pulmonary complications, nonpulmonary complications, >1 complication, duration of stay in the intensive care unit, duration of hospital stay, and death) was assessed by multivariate analysis using the appropriate model. RESULTS: A MRI LFF of ≥ 5% was associated with severe postoperative complications (Clavien-Dindo score ≥ IIIa; P = .04), more pulmonary complications (P = .02), and longer duration of hospital stay (P = .02) on the multivariate model adjusted for confounding factors. The postoperative aminotransferase levels were higher in patients with a MRI LFF of ≥ 5%, than in other patients (P = .0008). CONCLUSION: Liver steatosis assessed by routine preoperative MRI is shown to be an independent risk factor of severe postoperative complications after major liver resection.

MR fat fraction mapping: a simple biomarker for liver steatosis quantification in nonalcoholic fatty liver disease patients.

RATIONALE AND OBJECTIVES: To assess the performance, postprocessing time, and intra- and interobserver agreement of a simple magnetic resonance-based mapping technique to quantify liver fat. MATERIALS AND METHODS: This prospective, single-center study included 26 patients who were overweight with type 2 diabetes and at risk for nonalcoholic fatty liver disease. Mapping of the liver was based on a triple echo gradient-echo sequence, and (1)H magnetic resonance spectroscopy was used as the reference standard. The nonparametric Spearman correlation coefficient and the Wilcoxon test were used for comparisons between mapping and spectroscopy. The mapping was assessed for its predictive performance using the area under the curve of a receiver operating characteristic curve. Intraclass correlation coefficients were used to calculate intra- and interobserver's agreement for mapping measurements. RESULTS: Patients had a mean fat percentage of 11.7% (range, 2-35.4%). A strong correlation was seen between mapping and spectroscopy (r = 0.89, P < .0001). A cutoff of 6.9% for fat fraction mapping was found to diagnose steatosis with 93% sensitivity and 100% specificity with an area under the curve of 0.99. Mapping of the liver had shorter acquisition and post-processing times than spectroscopy (5 min vs. 38 min; P < .0001). Mapping measurements had an intra- and interobserver agreement of 0.98 and 0.99, respectively. CONCLUSIONS: The magnetic resonance-based liver mapping can accurately quantify liver fat with a cutoff value of 6.9% and excellent intra- and interobserver agreement. This mapping technique, with its simple methodology and short postprocessing time, has the potential to be included in routine abdominal protocols.

Determination of malignancy and characterization of hepatic tumor type with diffusion-weighted magnetic resonance imaging: comparison of apparent diffusion coefficient and intravoxel incoherent motion-derived measurements.

OBJECTIVE: The objective of this study was to compare the value of the apparent diffusion coefficient (ADC) determined with 3 b values and the intravoxel incoherent motion (IVIM)-derived parameters in the determination of malignancy and characterization of hepatic tumor type. MATERIALS AND METHODS: Seventy-six patients with 86 solid hepatic lesions, including 8 hemangiomas, 20 lesions of focal nodular hyperplasia, 9 adenomas, 30 hepatocellular carcinomas, 13 metastases, and 6 cholangiocarcinomas, were assessed in this prospective study. Diffusion-weighted images were acquired with 11 b values to measure the ADCs (with b = 0, 150, and 500 s/mm) and the IVIM-derived parameters, namely, the pure diffusion coefficient and the perfusion-related diffusion fraction and coefficient. The diffusion parameters were compared between benign and malignant tumors and between tumor types, and their diagnostic value in identifying tumor malignancy was assessed. RESULTS: The apparent and pure diffusion coefficients were significantly higher in benign than in malignant tumors (benign: 2.32 [0.87] × 10 mm/s and 1.42 [0.37] × 10 mm/s vs malignant: 1.64 [0.51] × 10 mm/s and 1.14 [0.28] × 10 mm/s, respectively; P < 0.0001 and P = 0.0005), whereas the perfusion-related diffusion parameters did not differ significantly between the 2 groups. The apparent and pure diffusion coefficients provided similar accuracy in assessing tumor malignancy (areas under the receiver operating characteristic curve of 0.770 and 0.723, respectively). In the multigroup analysis, the ADC was found to be significantly higher in hemangiomas than in hepatocellular carcinomas, metastases, and cholangiocarcinomas. In the same manner, it was higher in lesions of focal nodular hyperplasia than in metastases and cholangiocarcinomas. However, the pure diffusion coefficient was significantly higher only in hemangiomas versus hepatocellular and cholangiocellular carcinomas. CONCLUSIONS: Compared with the ADC, the diffusion parameters derived from the IVIM model did not improve the determination of malignancy and characterization of hepatic tumor type.

Fat deposition decreases diffusion parameters at MRI: a study in phantoms and patients with liver steatosis.

PURPOSE: Assess the effect of fat deposition on the MRI diffusion coefficients in lipid emulsion-based phantoms and patients with proven isolated liver steatosis. MATERIALS AND METHODS: Diffusion-weighted MRI with 11 b values from 0-500 s/mm(2) was performed in phantoms (fat fractions 0-18 %) with and without fat suppression and in 19 patients with normal liver (n = 14) or isolated liver steatosis (n = 5) proven by histopathology. The apparent, pure and perfusion-related diffusion coefficients and the perfusion fraction were measured. Spearman correlation coefficient and Mann-Whitney U test were used for comparisons. RESULTS: A strong correlation between the apparent and pure diffusion coefficients and fat fractions was seen in phantoms. The pure diffusion coefficient decreased significantly in patients with liver steatosis (0.96 ± 0.16 × 10(-3) mm(2)/s versus 1.18 ± 0.09 × 10(-3) mm(2)/s in normal liver, P = 0.005), whereas the decrease in apparent diffusion coefficient did not reach statistical significance (1.26 ± 0.25 × 10(-3) mm(2)/s versus 1.41 ± 0.14 × 10(-3) mm(2)/s in normal liver, P = 0.298). CONCLUSIONS: Fat deposition decreases the apparent and pure diffusion coefficients in lipid emulsion-based phantoms and patients with isolated liver steatosis proven by histopathology.

Diffusion-weighted MR imaging for the regional characterization of liver tumors.

PURPOSE: To determine if diffusion-weighted (DW) magnetic resonance (MR) imaging with measurements of the apparent diffusion coefficient (ADC), pure diffusion coefficient, perfusion-related diffusion coefficient, and perfusion fraction can be used to differentiate between viable tumor and fibrous and necrotic regions within malignant liver tumors. MATERIAL AND METHODS: The prospective study was approved by the institutional review board, and informed consent was obtained from all patients. Forty-eight patients with 51 malignant tumors were assessed. MR images of the liver were obtained by using DW imaging with 11 b factors (0-500 sec/mm(2)) and gadolinium-enhanced three-dimensional gradient-echo T1-weighted imaging. Tumors were segmented into viable tumor and fibrous and necrotic regions according to the enhancement pattern after injection of a nonspecific gadolinium chelate and, in surgically removed lesions, results of histopathologic correlation. The ADC, pure diffusion coefficient, perfusion-related diffusion coefficient, and perfusion fraction were calculated, and values were compared between viable tumor and fibrous and necrotic regions with the Kruskal-Wallis test followed by the Dunn multiple comparison test. RESULTS: The pure diffusion coefficient differed significantly between regions of viable tumor tissue and fibrosis (1.16 × 10(-3) mm(2)/sec ± 0.29 and 1.48 × 10(-3) mm(2)/sec ± 0.31, respectively; P = .016) and between regions of viable tumor tissue and necrosis (1.70 × 10(-3) mm(2)/sec ± 0.49, P = .002). There was a significantly lower perfusion fraction in necrotic regions (14% ± 6) than in viable tumor regions (21% ± 8, P = .005), but the perfusion fraction of the fibrous regions (21% ± 7) did not differ significantly from that of the other two regions. ADCs and perfusion-related diffusion coefficients did not differ significantly among the three regions. CONCLUSION: Results of this study show that viable tumor regions in malignant liver tumors can be differentiated from fibrous and necrotic regions with use of the pure diffusion coefficient but not with the other diffusion parameters.

MR elastography of liver tumours: value of viscoelastic properties for tumour characterisation.

OBJECTIVES: To assess the value of the viscoelastic parameters in the characterisation of liver tumours at MR elastography. PATIENTS AND METHODS: Ninety-four patients with liver tumours >1 cm prospectively underwent MR elastography using 50-Hz mechanical waves and a full three-directional motion-sensitive sequence. The model-free viscoelastic parameters (the complex shear modulus and its real and imaginary parts, i.e. the storage and loss moduli) were calculated in 72 lesions after exclusion of cystic, treated or histopathologically undetermined tumours. RESULTS: We observed higher absolute shear modulus and loss modulus in malignant versus benign tumours (3.38 ± 0.26 versus 2.41 ± 0.15 kPa, P < 0.01 and 2.25 ± 0.26 versus 1.05 ± 0.13 kPa, P < 0.001, respectively). Moreover, the loss modulus of hepatocellular carcinomas was significantly higher than in benign hepatocellular tumours. The storage modulus did not differ significantly between malignant and benign tumours. The area under the receiver-operating characteristic curve of loss modulus was significantly larger than that of the absolute shear modulus and storage modulus when comparing malignant and benign lesions. CONCLUSIONS: The increased loss modulus is a better discriminator between benign and malignant tumours than the increased storage modulus or absolute value of the shear modulus. KEY POINTS : • Magnetic Resonance elastography is a new method of assessing the liver. • Increased loss modulus is an indicator of malignancy in hepatic tumours. • Loss modulus is a better discriminator than absolute shear modulus values. • The viscoelastic properties of lesions offer promise for characterising liver tumours.

A uniform grid structure to speed up example-based photometric stereo.

In this paper, we describe a data structure and an algorithm to accelerate the table lookup step in example-based multiimage photometric stereo. In that step, one must find a pixel of a reference object, of known shape and color, whose appearance under m different illumination fields is similar to that of a given scene pixel. This search reduces to finding the closest match to a given m-vector in a table with a thousand or more m-vectors. Our method is faster than previously known solutions for this problem but, unlike some of them, is exact, i.e., always yields the best matching entry in the table, and does not assume point-like sources. Our solution exploits the fact that the table is in fact a fairly flat 2-D manifold in m-dimensional space so that the search can be efficiently solved with a uniform 2-D grid structure.

Mutual information content of homologous DNA sequences.

The necessary information to reproduce and keep an organism is codified in acid nucleic molecules. Deepening the knowledge about how the information is stored in these bio-sequences can lead to more efficient methods of comparing genomic sequences. In the present study, we analyzed the quantity of information contained in a DNA sequence that can be useful to identify sequences homologous to it. To reach it, we used signal processing techniques, specially spectral analysis and information theory.