A model of guided cell self-organization for rapid and spontaneous formation of functional vessels

Most achievements to engineer blood vessels are based on multiple-step manipulations such as manual sheet rolling or sequential cell seeding followed by scaffold degradation. Here, we propose a one-step strategy using a microfluidic coextrusion device to produce mature functional blood vessels. A hollow alginate hydrogel tube is internally coated with extracellular matrix to direct the self-assembly of a mixture of endothelial cells (ECs) and smooth muscle cells (SMCs). The resulting vascular structure has the correct configuration of lumen, an inner lining of ECs, and outer sheath of SMCs. These "vesseloids" reach homeostasis within a day and exhibit the following properties expected for functional vessels (i) quiescence, (ii) perfusability, and (iii) contractility in response to vasoconstrictor agents. Together, these findings provide an original and simple strategy to generate functional artificial vessels and pave the way for further developments in vascular graft and tissue engineering and for deciphering the angiogenesis process.

Implication of molecular vascular smooth muscle cell heterogeneity among arterial beds in arterial calcification

Vascular calcification is a strong and independent predictive factor for cardiovascular complications and mortality. Our previous work identified important discrepancies in plaque composition and calcification types between carotid and femoral arteries. The objective of this study is to further characterize and understand the heterogeneity in vascular calcification among vascular beds, and to identify molecular mechanisms underlying this process. We established ECLAGEN biocollection that encompasses human atherosclerotic lesions and healthy arteries from different locations (abdominal, thoracic aorta, carotid, femoral, and infrapopliteal arteries) for histological, cell isolation, and transcriptomic analysis. Our results show that lesion composition differs between these locations. Femoral arteries are the most calcified arteries overall. They develop denser calcifications (sheet-like, nodule), and are highly susceptible to osteoid metaplasia. These discrepancies may derive from intrinsic differences between SMCs originating from these locations, as microarray analysis showed specific transcriptomic profiles between primary SMCs isolated from each arterial bed. These molecular differences translated into functional disparities. SMC from femoral arteries showed the highest propensity to mineralize due to an increase in basal TGFβ signaling. Our results suggest that biological heterogeneity of resident vascular cells between arterial beds, reflected by our transcriptomic analysis, is critical in understanding plaque biology and calcification, and may have strong implications in vascular therapeutic approaches.

Long-lived tumor-associated macrophages in glioma

BACKGROUND

The tumor microenvironment plays a major tumor-supportive role in glioma. In particular, tumor-associated macrophages (TAMs), which can make up to one-third of the tumor mass, actively support tumor growth, invasion, and angiogenesis. Predominantly alternatively activated (M2-polarized) TAMs are found in late-stage glioma in both human and mouse tumors, as well as in relapse samples from patients. However, whether tumor-educated M2 TAMs can actively contribute to the emergence and growth of relapse is currently debated.

METHODS

To investigate whether tumor-educated stromal cells remaining in the brain after surgical removal of the primary tumor can be long-lived and retain their tumor-supporting function, we developed a transplantation mouse model and performed lineage-tracing.

RESULTS

We discovered that macrophages can survive transplantation and stay present in the tumor much longer than previously suggested, while sustaining an M2-polarized protumorigenic phenotype. Transplanted tumors showed a more aggressive growth and faster polarization of the TAMs toward an M2 phenotype compared with primary tumors, a process dependent on the presence of few cotransplanted macrophages.

CONCLUSIONS

Overall, we propose a new way for tumor-educated TAMs to contribute to glioma aggressiveness by long survival and stable protumorigenic features. These properties could have a relapse-supporting effect.

Dynamic changes in ventricular depolarization during exercise in patients with Brugada syndrome

Brugada syndrome (BS) is a genetic pathological condition associated with a high risk for sudden cardiac death (SCD). Ventricular depolarization disorders have been suggested as a potential electrophysiological mechanism associated with high SCD risk on patients with BS. This paper aims to characterize the dynamic changes of ventricular depolarization observed during physical exercise in symptomatic and asymptomatic BS patients. To this end, cardiac ventricular depolarization features were automatically extracted from 12-lead ECG recordings acquired during standardized exercise stress test in 110 BS patients, of whom 25 were symptomatic. Conventional parameters were evaluated, including QRS duration, R and S wave amplitudes (AR, AS), as well as QRS morphological features, such as up-stroke and down-stroke slopes of the R and S waves (UR, DR and US). The effects of physical exercise and recovery on the dynamics of these markers were assessed in both BS populations. Features showing significantly different dynamics between the studied groups were used alone and in combination with the clinical characteristics of the patients in a logistic regression analysis. Results show larger changes in the second half of the QRS complex through AS and US measured in the right precordial leads for asymptomatic patients, especially during recovery, when the vagal tone is more pronounced. Multivariate analysis involving both types of features resulted in a reduced model of three relevant features (ΔAS in lead V2, Sex and heart rate recovery, HRR), which achieved a suitable discrimination performance between groups; sensitivity = 80% and specificity = 75% (AUC = 83%). However, after controlling the model for possible confounding factors, only one feature (ΔAS) remained meaningful. This adjusted model significantly improved the overall discrimination performance by up to: sensitivity = 84% and specificity = 100% (AUC = 94%). The study highlights the importance of physical exercise test to unmask differentiated behaviors between symptomatic and asymptomatic BS patients through depolarization dynamic analysis. This analysis together with the obtained model may help to identify asymptomatic patients at low or high risk of future cardiac events, but it should be confirmed by further prospective studies.

Open-source software for respiratory rate estimation using single-lead electrocardiograms

Respiratory rate (RR) is a critical vital sign used to assess pulmonary function. Currently, RR estimating instrumentation is specialized and bulky, therefore unsuitable for remote health monitoring. Previously, RR was estimated using proprietary software that extract surface electrocardiogram (ECG) waveform features obtained at several thoracic locations. However, developing a non-proprietary method that uses minimal ECG leads, generally available from mobile cardiac monitors is highly desirable. Here, we introduce an open-source and well-documented Python-based algorithm that estimates RR requiring only single-stream ECG signals. The algorithm was first developed using ECGs from awake, spontaneously breathing adult human subjects. The algorithm-estimated RRs exhibited close linear correlation to the subjects' true RR values demonstrating an R2 of 0.9092 and root mean square error of 2.2 bpm. The algorithm robustness was then tested using ECGs generated by the ischemic hearts of anesthetized, mechanically ventilated sheep. Although the ECG waveforms during ischemia exhibited severe morphologic changes, the algorithm-determined RRs exhibited high fidelity with a resolution of 1 bpm, an absolute error of 0.07 ± 0.07 bpm, and a relative error of 0.67 ± 0.64%. This optimized Python-based RR estimation technique will likely be widely adapted for remote lung function assessment in patients with cardiopulmonary disease.

Automatically optimized vectorcardiographic features are associated with recurrence of atrial fibrillation after electrical cardioversion

Electrical cardioversion presents one of the treatment options for atrial fibrillation (AF). However, the early recurrence rate is high, reaching ~40% three months after the procedure. Features based on vectorcardiographic signals were explored to find association with early recurrence of AF. Eighty-four patients with non-paroxysmal AF referred to electrical cardioversion were prospectively studied; early AF recurrence was present in 40 (47.6%). Patients underwent 24-h Holter ECG monitoring three months after the procedure to assess AF recurrence. Pre-procedural 12-lead ECGs (10 s, 1 kHz) were recorded and automatically analyzed. We explored associations of VCG-based features with early AF recurrence. Two features were strongly associated with AF recurrence: (1) a mean VCG (y-axis) signal slope in a window starting 145 ms before QRS center, lasting for 190 ms (AUC 0.778, p < 0.001), and (2) a mean VCG (z-axis) signal slope in a window starting 60 ms after QRS center, lasting for 465 ms (AUC 0.744, p < 0.001). These features showed higher association to the outcome than eighteen baseline clinical features. Our approach revealed features based on a slope of vectorcardiographic signals. This work also suggests that state of ventricles strongly affects the AF recurrence after electrical cardioversion.

Micro-Scale Topography Triggers Dynamic 3D Nuclear Deformations

Navigating complex extracellular environments requires extensive deformation of cells and their nuclei. Most in vitro systems used to study nuclear deformations impose whole-cell confinement that mimics the physical crowding experienced by cells during 3D migration through tissues. Such systems, however, do not reproduce the types of nuclear deformations expected to occur in cells that line tissues such as endothelial or epithelial cells whose physical confinement stems principally from the topography of their underlying basement membrane. Here, it is shown that endothelial cells and myoblasts cultured on microgroove substrates that mimic the anisotropic topography of the basement membrane exhibit large-scale 3D nuclear deformations, with partial to complete nuclear penetration into the microgrooves. These deformations do not lead to significant DNA damage and are dynamic with nuclei cyclically entering and exiting the microgrooves. Atomic force microscopy measurements show that these deformation cycles are accompanied by transient changes in perinuclear stiffness. Interestingly, nuclear penetration into the grooves is driven principally by cell-substrate adhesion stresses, with a limited need for cytoskeleton-associated forces. Finally, it is demonstrated that myoblasts from laminopathy patients exhibit abnormal nuclear deformations on microgrooves, raising the possibility of using microgroove substrates as a novel functional diagnostic platform for pathologies that involve abnormal nuclear mechanics.

Homozygous TNNI3 frameshift variant in a consanguineous family with lethal infantile dilated cardiomyopathy

BACKGROUND

Dilated cardiomyopathy (DCM) is characterized by dilatation of the left ventricle, systolic dysfunction, and normal or reduced thickness of the left ventricular wall. It is a leading cause of heart failure and cardiac death at a young age. Cases with neonatal onset DCM were correlated with severe clinical presentation and poor prognosis. A monogenic molecular etiology accounts for nearly half of cases.

FAMILY DESCRIPTION

Here, we report a family with three deceased offspring at the age of 1 year old. The autopsy of the first deceased infant revealed a DCM. The second infant presented a DCM phenotype with a severely reduced Left Ventricular Ejection Fraction (LVEF) of 10%. Similarly, the third infant showed a severe DCM phenotype with LVEF of 30% as well, in addition to eccentric mitral insufficiency.

RESULTS

Exome sequencing was performed for the trio (the second deceased infant and her parents). Data analysis following the autosomal dominant and recessive patterns of inheritance was carried out along with a mitochondrial pathways-based analysis. We identified a homozygous frameshift variant in the TNNI3 gene (c.204delG; p.(Arg69AlafsTer8)). This variant has been recently reported in the ClinVar database in association with cardiac phenotypes as pathogenic or likely pathogenic and classified as pathogenic according to ACMG.

CONCLUSION

Genetic counseling was provided for the family and a prenatal diagnosis of choronic villus was proposed in the absence of pre-implantation genetic diagnosis possibilities. Our study expands the case series of early-onset DCM patients with a protein-truncating variant in the TNNI3 gene by reporting three affected infant siblings.