Cumulative Brain Injury from Motor Vehicle-Induced Whole-Body Vibration and Prevention by Human Apolipoprotein A-I Molecule Mimetic (4F) Peptide (an Apo A-I Mimetic)

The HDL-Mimetic Peptide 4F Mitigates Vascular and Cortical Amyloid Pathology and Associated Neuroinflammation in a Transgenic Mouse Model of Cerebral Amyloid Angiopathy and Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia worldwide. Despite recent advances, more effective and safer treatment options for AD are needed. Cerebral amyloid angiopathy (CAA) is one of the key pathological hallmarks of AD characterized by amyloid-β (Aβ) deposition in the cerebral vasculature and is associated with intracerebral hemorrhage, cerebrovascular dysfunction, and cognitive impairment. CAA is also considered to underlie the main adverse effect of recently FDA-approved anti-Aβ immunotherapies, namely the amyloid-related imaging abnormalities (ARIA). Substantial evidence has shown that elevated levels of high-density lipoprotein (HDL) and its main protein component, APOA-I, are associated with reduced CAA and superior cognitive function. 4F is an APOA-I/HDL-mimetic peptide and its clinical safety and activity have been demonstrated in human trials for cardiovascular diseases. The present study investigates whether treatment with 4F modulates CAA and associated cognitive deficits and neuropathologies in the well-established Tg-SwDI mouse model of CAA/AD. Age/sex-matched Tg-SwDI mice received daily treatments of 4F or vehicle (PBS), respectively, by intraperitoneal injections for 12 weeks. The results showed that 4F treatment reduced overall Aβ plaque deposition and CAA, and attenuated CAA-associated microgliosis, without significantly affecting total levels of Aβ, astrocytosis, and behavioral function. Unbiased transcriptomic analysis revealed a heightened inflammatory state in the brain of SwDI mice and that 4F treatment reversed the overactivation of vascular cells, in particular vascular smooth muscle cells, relieving cerebrovascular inflammation in CAA/AD mice. Our study provides experimental evidence for the therapeutic potential of 4F to mitigate CAA and associated pathologies in AD.

Case studies in neuroscience: reversible signatures of edema following electric and piezoelectric craniotomy drilling in macaques

In vivo electrophysiology requires direct access to brain tissue, necessitating the development and refinement of surgical procedures and techniques that promote the health and well-being of animal subjects. Here, we report a series of findings noted on structural magnetic resonance imaging (MRI) scans in monkeys with MRI-compatible implants following small craniotomies that provide access for intracranial electrophysiology. We found distinct brain regions exhibiting hyperintensities in T2-weighted scans that were prominent underneath the sites at which craniotomies had been performed. We interpreted these hyperintensities as edema of the neural tissue and found that they were predominantly present following electric and piezoelectric drilling, but not when manual, hand-operated drills were used. Furthermore, the anomalies subsided within 2-3 wk following surgery. Our report highlights the utility of MRI-compatible implants that promote clinical examination of the animal's brain, sometimes revealing findings that may go unnoticed when incompatible implants are used. We show replicable differences in outcome when using electric versus mechanical devices, both ubiquitous in the field. If electric drills are used, our report cautions against electrophysiological recordings from tissue directly underneath the craniotomy for the first 2-3 wk following the procedure due to putative edema.NEW & NOTEWORTHY Close examination of structural MRI in eight nonhuman primates following craniotomy surgeries for intracranial electrophysiology highlights a prevalence of hyperintensities on T2-weighted scans following surgeries conducted using electric and piezoelectric drills, but not when using mechanical, hand-operated drills. We interpret these anomalies as edema of neural tissue that resolved 2-3 wk postsurgery. This finding is especially of interest as electrophysiological recordings from compromised tissue may directly influence the integrity of collected data immediately following surgery.

Beneficial effects of whole-body vibration exercise for brain disorders in experimental studies with animal models: a systematic review

Brain disorders have been a health challenge and is increasing over the years. Early diagnosis and interventions are considered essential strategies to treat patients at risk of brain disease. Physical exercise has shown to be beneficial for patients with brain diseases. A type of exercise intervention known as whole-body vibration (WBV) exercise gained increasing interest. During WBV, mechanical vibrations, produced by a vibrating platform are transmitted, to the body. The purpose of the current review was to summarize the effects of WBV exercise on brain function and behavior in experimental studies with animal models. Searches were performed in EMBASE, PubMed, Scopus and Web of Science including publications from 1960 to July 2021, using the keywords "whole body vibration" AND (animal or mice or mouse or rat or rodent). From 1284 hits, 20 papers were selected. Rats were the main animal model used (75%) followed by mice (20%) and porcine model (5%), 16 studies used males species and 4 females. The risk of bias, accessed with the SYRCLE Risk of Bias tool, indicated that none of the studies fulfilled all methodological criteria, resulting in possible bias. Despite heterogeneity, the results suggest beneficial effects of WBV exercise on brain functioning, mainly related to motor performance, coordination, behavioral control, neuronal plasticity and synapse function. In conclusion, the findings observed in animal studies justifies continued clinical research regarding the effectiveness and potential of WBV for the treatment of various types of brain disorders such as trauma, developmental disorders, neurogenetic diseases and other neurological diseases.

Managing Vibration Training Safety by Using Knee Flexion Angle and Rating Perceived Exertion

Whole-body vibration (WBV) is commonly applied in exercise and rehabilitation and its safety issues have been a major concern. Vibration measured using accelerometers can be used to further analyze the vibration transmissibility. Optimal bending angles and rating of perceived exertion (RPE) evaluations have not been sufficiently explored to mitigate the adverse effect. Therefore, the aims of this study were to investigate the effect of various knee flexion angles on the transmissibility to the head and knee, the RPE during WBV exposure, and the link between the transmissibility to the head and the RPE. Sixteen participants randomly performed static squats with knee flexion angles of 90, 110, 130, and 150 degrees on a WBV platform. Three accelerometers were fixed on the head, knee, and center of the vibration platform to provide data of platform-to-head and platform-to-knee transmissibilities. The results showed that the flexion angle of 110 degrees induced the lowest platform-to-head transmissibility and the lowest RPE (p < 0.01). A positive correlation between RPE and the platform-to-head transmissibility was observed. This study concluded that a knee flexion of about 110 degrees is most appropriate for reducing vibration transmissibility. The reported RPE could be used to reflect the vibration impact to the head.

The Role of HDL and HDL Mimetic Peptides as Potential Therapeutics for Alzheimer's Disease

The role of high-density lipoproteins (HDL) in the cardiovascular system has been extensively studied and the cardioprotective effects of HDL are well established. As HDL particles are formed both in the systemic circulation and in the central nervous system, the role of HDL and its associated apolipoproteins in the brain has attracted much research interest in recent years. Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder and the leading cause of dementia worldwide, for which there currently exists no approved disease modifying treatment. Multiple lines of evidence, including a number of large-scale human clinical studies, have shown a robust connection between HDL levels and AD. Low levels of HDL are associated with increased risk and severity of AD, whereas high levels of HDL are correlated with superior cognitive function. Although the mechanisms underlying the protective effects of HDL in the brain are not fully understood, many of the functions of HDL, including reverse lipid/cholesterol transport, anti-inflammation/immune modulation, anti-oxidation, microvessel endothelial protection, and proteopathy modification, are thought to be critical for its beneficial effects. This review describes the current evidence for the role of HDL in AD and the potential of using small peptides mimicking HDL or its associated apolipoproteins (HDL-mimetic peptides) as therapeutics to treat AD.

Matrix Deformation with Ectopic Cells Induced by Rotational Motion in Bioengineered Neural Tissues

The brain's extracellular matrix (ECM) is a dynamic protein-based scaffold within which neural networks can form, self-maintain, and re-model. When the brain incurs injuries, microscopic tissue tears and active ECM re-modelling give way to abnormal brain structure and function including the presence of ectopic cells. Post-mortem and neuroimaging data suggest that the brains of jet pilots and astronauts, who are exposed to rotational forces, accelerations, and microgravity, display brain anomalies which could be indicative of a mechanodisruptive pathology. Here we present a model of non-impact-based brain injury induced by matrix deformation following mechanical shaking. Using a bioengineered 3D neural tissue platform, we designed a repetitive shaking paradigm to simulate subtle rotational acceleration. Our results indicate shaking induced ectopic cell clustering that could be inhibited by physically restraining tissue movement. Imaging revealed that the collagen substrate surrounding cells was deformed following shaking. Applied to neonatal rat brains, shaking induced deformation of extracellular spaces within the cerebral cortices and reduced the number of cell bodies at higher accelerations. We hypothesize that ECM deformation may represent a more significant role in brain injury progression than previously assumed and that the present model system contributes to its understanding as a phenomenon.

Whole-body vibration in neonatal transport: a review of current knowledge and future research challenges

Interfacility transport to tertiary care for high-risk neonates has become an integral part of equitable access to optimal perinatal healthcare. Excellence in clinical care requires expertise in transport medicine and the coordination of safe transport processes. However, concerns remain regarding environmental stressors involved in the transportation of sick high-risk neonates, including noise and vibration. In order to mitigate the potential deleterious effects of these physical stressors during transport, further knowledge of the burden of exposure, injury mechanisms and engineering interventions/modifications as adjuncts during transport would be beneficial. We reviewed the current literature with a focus on the contribution of new and emerging technologies in the transport environment with particular reference to whole-body vibration. This review intends to highlight what is known about vibration as a physical stressor in neonates and areas for further research; with the goal to making recommendations for minimizing these stressors during transport.

Vibration Does Not Affect Short Term Outcomes Following Traumatic Brain Injury in a Porcine Model

Introduction

Traumatic brain injury (TBI) has become increasingly prevalent among the injuries sustained in the military. Many wounded warriors require emergency medical evacuation via helicopter and subsequently fixed wing transport. During aeromedical evacuation, both pilots and patients experience whole body vibration due to engine, rotor, and propeller rotation. The impact of posttraumatic vibration and hypoxia exposure characteristic of the aeromedical evacuation environment on TBI is currently unknown.

Methods

A swine TBI model of controlled cortical impact was utilized. The pigs first underwent TBI or sham injury and were subsequently exposed to vibration or no vibration and hypoxia or normoxia for 2 hours. They were monitored for an additional 4 hours following vibration/hypoxia and blood was drawn at hourly intervals for cytokine and serum biomarker analysis. Continuous physiologic and neurologic monitoring were utilized. Prior to the conclusion of the experiment, the animals underwent brain magnetic resonance imaging. At the end of the study, the brain was extracted for histologic analysis.

Results

Physiologic parameters except for peripheral capillary oxygen saturation (SpO2) were similar between all groups. The hypoxia groups demonstrated the expected decrease in SpO2 and pO2 during the hypoxic period, and this was sustained throughout the study period. The pH, pCO2 and electrolytes were similar among all groups. Neuron specific enolase was increased over time in the TBI group, however it was similar to the sham TBI group at all time points. There were no differences in IL-1β, IL-6, IL-8, TNFα, GFAP, HIF1α, syndecan-1, or S100β serum levels between groups. The mean ICP during cortical impact in the TBI group was 279.8 ± 56.2 mmHg. However, the postinjury ICP was not different between groups at any subsequent time point. Brain tissue oxygenation and perfusion were similar between all groups.

Conclusion

In this novel study evaluating the effect of vibration on short-term outcomes following TBI, we demonstrate that the moderate vibration and hypoxia simulating aeromedical evacuation do not impact short term outcomes following TBI.