Case Report: No Evidence of Intracranial Fluid Shifts in an Astronaut Following an Aborted Launch

Spaceflight induces lasting enlargement of the brain's ventricles as well as intracranial fluid shifts. These intracranial fluid shifts have been attributed to prolonged microgravity exposure, however, the potential effects of hypergravity exposure during launch and landing have yet to be elucidated. Here we describe a case report of a Crewmember who experienced an Aborted Launch (“CAL”). CAL's launch and landing experience was dissociated from prolonged microgravity exposure. Using MRI, we show that hypergravity exposure during the aborted launch did not induce lasting ventricular enlargement or intracranial fluid shifts resembling those previously reported with spaceflight. This case study therefore rules out hypergravity during launch and landing as a contributing factor to previously reported long-lasting intracranial fluid changes following spaceflight.

Radiological Cardiothoracic Ratio as a Potential Predictor of Right Ventricular Enlargement in Patients with Suspected Pulmonary Embolism Due to COVID-19

The aim of the study was to determine the usefulness of the radiological cardiothoracic ratio (CTR) as a predictor of right ventricular enlargement in patients with suspected pulmonary embolism during COVID-19. The study group consisted of 61 patients with confirmed COVID-19, suspected of pulmonary embolism based on physical examination and laboratory tests (age: 67.18 ± 12.47 years). Computed tomography angiography (CTA) of pulmonary arteries and chest radiograph in AP projection with cardiothoracic ratio assessment were performed in all patients. Right ventricular enlargement was diagnosed by the ratio of right ventricular to left ventricular (RV/LV) dimensions in pulmonary CTA with two cut-off points: ≥0.9 and ≥1.0. Heart silhouette enlargement was found when CTR on the chest radiograph in the projection AP > 0.55. The mean values of RV/LV and CTR in the studied group were 0.96 ± 0.23 and 0.57 ± 0.05, respectively. Pulmonary embolism was diagnosed in 45.9%. Right ventricular enlargement was documented in 44.3% or 29.5% depending on the adopted criterion RV/LV ≥ 0.9 or RV/LV ≥ 1.0. Heart silhouette enlargement was found in 60.6%. Patients with confirmed pulmonary embolism (PE+) had a significantly higher RV/LV ratio and CTR than patients with excluded pulmonary embolism (PE−) (RV/LV: PE+ 1.08 ± 0.24, PE− 0.82 ± 0.12; CTR: PE+ 0.60 ± 0.05, PE− 0.54 ± 0.04; p < 0.05). The correlation analysis showed a statistically significant positive correlation between the RV/LV ratio and CTR (r = 0.59, p < 0.05). Based on the ROC curves, CTR values were determined as the optimal cut-off points for the prediction of right ventricular enlargement (RV/LV ≥ 0.9 or RV/LV ≥ 1.0), being 0.54 and 0.55, respectively. The sensitivity, specificity, and accuracy of the CTR criterion >0.54 as a predictor of RV/LV ratio ≥0.9 were 0.412, 0.963, and 0.656, respectively, while those of the CTR criterion >0.55 as a predictor of RV/LV ratio ≥1.0 were 0.488, 0.833, and 0.590, respectively. In summary, in patients with suspected pulmonary embolism during COVID-19, the radiographic cardiothoracic ratio can be considered as a prognostic factor for right ventricular enlargement, especially as a negative predictor of right ventricular enlargement in the case of lower CTR values.

Differential Cognitive Decline in Alzheimer’s Disease Is Predicted by Changes in Ventricular Size but Moderated by Apolipoprotein E and Pulse Pressure

Background: Differential cognitive trajectories in Alzheimer’s disease (AD) may be predicted by biomarkers from multiple domains. Objective: In a longitudinal sample of AD and AD-related dementias patients (n = 312), we tested whether 1) change in brain morphometry (ventricular enlargement) predicts differential cognitive trajectories, 2) further risk is contributed by genetic (Apolipoprotein E [APOE] ɛ4+) and vascular (pulse pressure [PP]) factors separately, and 3) the genetic + vascular risk moderates this pattern. Methods: We applied a dynamic computational approach (parallel process models) to test both concurrent and change-related associations between predictor (ventricular size) and cognition (executive function [EF]/attention). We then tested these associations as stratified by APOE (ɛ4–/ɛ4+), PP (low/high), and APOE+ PP (low/intermediate/high) risk. Results: First, concurrently, higher ventricular size predicted lower EF/attention performance and, longitudinally, increasing ventricular size predicted steeper EF/attention decline. Second, concurrently, higher ventricular size predicted lower EF/attention performance selectively in APOE ɛ4+ carriers, and longitudinally, increasing ventricular size predicted steeper EF/attention decline selectively in the low PP group. Third, ventricular size and EF/attention associations were absent in the high APOE+ PP risk group both concurrently and longitudinally. Conclusion: As AD progresses, a threshold effect may be present in which ventricular enlargement in the context of exacerbated APOE+ PP risk does not produce further cognitive decline.

Nutrients, Cognitive Function, and Brain Aging: What We Have Learned from Dogs

Due to a difference in genetics, environmental factors, and nutrition, just like in people, dogs age at different rates. Brain aging in people and dogs share similar morphological changes including irreversible cortical atrophy, cerebral amyloid angiopathy, and ventricular enlargement. Due to severe and irreversible brain atrophy, some aging dogs develop cognitive dysfunction syndrome (CDS), which is equivalent to dementia or Alzheimer’s disease (AD) in people. The risk factors and causes of CDS in dogs have not been fully investigated, but age, gender, oxidative stress, and deficiency of sex hormones appears to be associated with increased risk of accelerated brain aging and CDS in dogs. Both AD and CDS are incurable diseases at this moment, therefore more efforts should be focused on preventing or reducing brain atrophy and minimizing the risk of AD in people and CDS in dogs. Since brain atrophy leads to irreversible cognitive decline and dementia, an optimal nutritional solution should be able to not only enhance cognitive function during aging but also reduce irreversible brain atrophy. Up to now, only one nutritional intervention has demonstrated both cognition-enhancing benefits and atrophy-reducing benefits.

Post-injury ventricular enlargement associates with iron in choroid plexus but not with seizure susceptibility nor lesion atrophy—6-month MRI follow-up after experimental traumatic brain injury

Ventricular enlargement is one long-term consequence of a traumatic brain injury, and a risk factor for memory disorders and epilepsy. One underlying mechanisms of the chronic ventricular enlargement is disturbed cerebrospinal-fluid secretion or absorption by choroid plexus. We set out to characterize the different aspects of ventricular enlargement in lateral fluid percussion injury (FPI) rat model by magnetic resonance imaging (MRI) and discovered choroid plexus injury in rats that later developed hydrocephalus. We followed the brain pathology progression for 6 months and studied how the ventricular growth was associated with the choroid plexus injury, cortical lesion expansion, hemorrhagic load or blood perfusion deficits. We correlated MRI findings with the seizure susceptibility in pentylenetetrazol challenge and memory function in Morris water-maze. Choroid plexus injury was validated by ferric iron (Prussian blue) and cytoarchitecture (Nissl) stainings. We discovered choroid plexus injury that accumulates iron in 90% of FPI rats by MRI. The amount of the choroid plexus iron remained unaltered 1-, 3- and 6-month post-injury. During this time, the ventricles kept on growing bilaterally. Ventricular growth did not depend on the cortical lesion severity or the cortical hemorrhagic load suggesting a separate pathology. Instead, the results indicate choroidal injury as one driver of the post-traumatic hydrocephalus, since the higher the choroid plexus iron load the larger were the ventricles at 6 months. The ventricle size or the choroid plexus iron load did not associate with seizure susceptibility. Cortical hypoperfusion and memory deficits were worse in rats with greater ventricular growth.

Piezo Type Mechanosensitive Ion Channel Component 1 is Required for Heart Development in Zebrafish

PIEZO1 is a non-selective cation channel protein that converts mechanical stimuli into electrochemical signals through mechanical force transmission. In recent years, more and more attention has been paid to its relationship with cardiovascular development and related diseases. However, PIEZO1 is difficult to be used as a therapeutic target due to incomplete study of its related phenotype and mechanism. Starting with the phenotypes of zebrafish at different stages of development, piezo1 knockout zebrafish features decreased heart rate in embryonic stage, increased heart size in 72dpf larvae, as well as ventricular enlargement, passivation and increased immune infiltration in adult stage. Further characterization revealed the relationship between PIEZO1 and AcanA protein at embryonic stage, and hand2 protein at adult stage. Through further RNA-seq analysis, ptpn21 downregulation, shox2 upregulation, itga4 upregulation were used to explain ventricular enlargement, heart rate decrease and immune infiltration increase respectively. Overall, this study provides a theoretical basis for elucidating the mechanism of PIEZO1 in regulating cardiac development.

Electrocardiographic Interpretations of Cardiac Disorders in Dogs

Background: Cardiac disorders are the second most common disorders after cancer in dogs. Cardiac disorders are often fatal and/or silent killers in canines. In our country, in the majority of cardiovascular disorders, there is a frequent omission by clinician and client due to lack of awareness. However, any cardiac abnormality requires to be dealt with top priority to avoid morbidity and mortality in the dog population. The present study was aimed to know the electrocardiographic interpretations of cardiac disorders in dogs. Methods: For this purpose, a total of 5110 dogs presented at Veterinary Clinical Complex, College of Veterinary Science and Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur, Madhya Pradesh, from November 2019 to June 2020 were screened. Among them, 137 dogs had clinical signs about cardiac disorders were subjected to thorough electrocardiographic recordings for interpretations of various cardiac conduction anomalies. Result: Electrocardiography revealed various types of supraventricular and ventricular abnormalities. Among supraventricular disorders maximally wandering pacemaker (30.60%) was recorded followed by atrial fibrillation (22.58%), left atrial enlargement (8.06%) and sinus arrest (4.84%) in dogs. Among ventricular abnormalities; left ventricular enlargement, right ventricular enlargement and biventricular enlargement (i.e. 41.67%, 37.49% and 8.33%, respectively) were commonly diagnosed.

Incidence and Clinical Significance of Worsening Tricuspid Regurgitation Following Surgical or Transcatheter Aortic Valve Replacement: Analysis From the PARTNER IIA Trial

Background: Aortic valve replacement (AVR) is recommended for severe symptomatic aortic stenosis. However, the incidence of worsening tricuspid regurgitation (TR) following transcatheter compared with surgical AVR (TAVR, SAVR), and the impact of worsening TR on outcomes, is ill-defined. Accordingly, among patients randomized to TAVR or SAVR, we describe the differential incidence of worsening TR and its association with survival. Methods: From the PARTNER IIA trial (Placement of Aortic Transcatheter Valves IIA), 1334 patients were included with baseline and 30-day postprocedure core-lab echocardiograms. Worsening TR was defined as deterioration of ≥1 grade from baseline to 30 days. Outcomes included cardiovascular and all-cause death between 30 days and 2 years. Multivariable logistic regression was performed to identify associations with worsening TR; survival analyses were performed to assess associations with mortality. Results: Worsening TR occurred in 17.3% (125/721) of TAVR and 27.0% (165/611) of SAVR patients. On multivariable analysis, SAVR (odds ratio, 2.09 [95% CI, 1.40–3.11]), female sex (odds ratio, 2.22 [95% CI, 1.44–3.42]), atrial fibrillation (odds ratio, 1.61 [95% CI, 1.03–2.51]), and right ventricular enlargement (odds ratio, 2.25 [95% CI, 1.17–4.31]) were associated with worsening TR. Cardiovascular and all-cause death occurred in 9.0% (26/290) and 17.9% (52/290) of patients with worsening TR, compared with 4.8% (50/1042) and 10.9% (114/1042) without worsening TR, respectively. In patients with worsening TR, cardiovascular and all-cause death were similar in TAVR compared with SAVR, (hazard ratio, 1.09 [95% CI, 0.55–2.16]) and (hazard ratio, 1.07 [95% CI, 0.62–1.87]), respectively. After adjustment, worsening TR was independently associated with cardiovascular (hazard ratio, 3.62 [95% CI, 2.08–6.29]) and all-cause death (hazard ratio, 2.11 [95% CI, 1.37–3.27]). Conclusions: Worsening TR is associated with female sex, atrial fibrillation, right ventricular enlargement, and SAVR. Regardless of mode of AVR, worsening TR is similarly associated with a poor prognosis. Future studies should focus on whether preventing or treating worsening TR improves outcomes. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01314313.