Telomere Length Associates With Symptom Severity After Mild Traumatic Brain Injury in Older Adults.

The objectives were to compare differences in telomere length (TL) among younger (21-54 years) and older adults (≥55) with mild traumatic brain injury (mTBI) to non-injured controls and to examine the association between TL and the severity of post-concussive symptoms over time. We performed a quantitative polymerase chain reaction to determine the TL (Kb/genome) of peripheral blood mononuclear cell samples (day 0, 3 months, and 6 months) from 31 subjects. The Rivermead Post-Concussion Symptoms Questionnaire was used to assess symptoms. Group-by-time comparisons of TL and symptom severity were evaluated with repeated-measures analysis of variance. Multiple linear regression examined the relationship between TL, group (mTBI and non-injured controls), and symptom severity total and subscale scores. Significant aging-related differences in TL were found within mTBI groups by time (day 0, 3 months, and 6 months; p = 0.025). Older adults with mTBI experienced significant worsening of changes in total symptom severity scores over time (day 0, 3 months, and 6 months; p = 0.016). Shorter TLs were associated with higher total symptom burden among each of the four groups at day 0 (baseline; p = 0.035) and 3 months (p = 0.038). Shorter TL was also associated with higher cognitive symptom burden among the four groups at day 0 (p = 0.008) and 3 months (p = 0.008). Shorter TL was associated with higher post-injury symptom burden to 3 months in both older and younger persons with mTBI. Large-scale, longitudinal studies of factors associated with TL may be useful to delineate the mechanistic underpinnings of higher symptom burden in adults with mTBI.

Lipidomics, Acute Ischemic Stroke, Symptoms, and Outcomes: Observational Study Protocol.

BACKGROUND: Acute ischemic stroke is one of the leading causes of death and disability globally. Recent advances in omics methodology enable lipidomic profiling, which may provide knowledge of the underlying pathology of acute ischemic stroke and its associated outcomes. OBJECTIVE: This study aims to examine the longer-term relationships between symptoms and outcomes following acute ischemic stroke and the underlying lipidomic signatures over 6 months during recovery between acute ischemic stroke patients who received reperfusion therapies and those who did not. METHODS: This prospective cohort study will enroll 104 participants post-acute ischemic stroke in two groups based on their receipt of reperfusion therapy (Group 1) or not (Group 2; n = 52/group). Peripheral plasma samples will be collected from both groups for lipidomic analysis over 6 months. Arterial blood samples will be collected during the procedure for those receiving reperfusion. Self-reported symptoms and outcome data will be collected from both groups. DISCUSSION: We will compare and examine the associations among plasma lipidomic biomarkers and symptoms and cognitive, functional, and health-related quality of life outcomes over 6 months between acute ischemic stroke patients who did and did not receive reperfusion intervention.

Machine Learning Analysis of the Cerebrovascular Thrombi Lipidome in Acute Ischemic Stroke.

ABSTRACT: OBJECTIVE: The aim of this study was to identify a signature lipid profile from cerebral thrombi in acute ischemic stroke (AIS) patients at the time of ictus. METHODS: We performed untargeted lipidomics analysis using liquid chromatography-mass spectrometry on cerebral thrombi taken from a nonprobability, convenience sampling of adult subjects (≥18 years old, n = 5) who underwent thrombectomy for acute cerebrovascular occlusion. The data were classified using random forest, a machine learning algorithm. RESULTS: The top 10 metabolites identified from the random forest analysis were of the glycerophospholipid species and fatty acids. CONCLUSION: Preliminary analysis demonstrates feasibility of identification of lipid metabolomic profiling in cerebral thrombi retrieved from AIS patients. Recent advances in omic methodologies enable lipidomic profiling, which may provide insight into the cellular metabolic pathophysiology caused by AIS. Understanding of lipidomic changes in AIS may illuminate specific metabolite and lipid pathways involved and further the potential to develop personalized preventive strategies.

Ischemic Stroke Risk Among Adult Brain Tumor Survivors: Evidence to Guide Practice.

ABSTRACT: INTRODUCTION: Primary brain tumors are the leading cause of cancer mortality in the United States affecting approximately 90,000 Americans each year. A major complication for brain tumor survivors is acute ischemic stroke (AIS). Currently, there are limited research to provide guidelines for AIS prevention and management in adult brain tumor survivors. The purpose of this review is to discuss the most common risk factors for AIS in adult brain tumor survivors along with best evidence for assessment, screening, and strategies to prevent AIS in this population. METHODS: Relevant literature was identified by searching CINAHL and PubMed databases using the following keywords: "brain tumor survivors," "adults," "stroke," "risk factors," "guidelines," "prevention," and "management". Articles not pertaining to adult brain tumor survivors and AIS were excluded. RESULTS: The location of the tumor, dose, extent, and type of radiation contribute to the development of vascular injury and subsequent carotid stenosis among brain tumor survivors. Endothelial growth factor inhibitor and chemotherapy drugs induces vascular remodeling. Other symptoms such as neurological impairments and co-morbidities are also present among brain tumor survivors. Furthermore, AIS increases from the time of primary brain tumor diagnosis and incidence further increases among patients who were diagnosed with a brain tumor as a child. CONCLUSION: Nurses play a key role in the assessment, prevention, and identifying individuals who are at risk of AIS during brain tumor survivorship. Engaging patients and their caregivers on minimizing their risks of AIS is crucial in the outpatient setting. Annual surveillance visits that include intracranial artery imaging should be used to identify individuals considered most at risk for developing AIS symptoms.

Plasma Phospholipid Metabolites Associate With Functional Outcomes Following Mild Traumatic Brain Injury in Older Adults.

OBJECTIVE: To compare differences using a metabolomics approach in older adults (≥55) with mild traumatic brain injury (mTBI) to control adults and to identify a signature profile related to functional outcome 3-6 months post-injury. METHODS: We performed metabolomics analysis using LC-MS of untargeted aqueous metabolites on plasma samples taken from a parent prospective cohort study. Older adults with mTBI (n = 14) were purposively sampled to include participants with worsening (decrease in GOS-E of at least 1 level) and improved (increase in GOS-E of at least 1 level) outcomes from 3 to 6 months. The data were analyzed using PLS-DA with VIP scores, Random Forest, and spline fit between the different groups as a function of time for exposure on outcome. RESULTS: Separation of comparisons were seen at 24 hours (negative ionization) and 6 months (positive ionization), revealing two metabolites of interest, phosphatidylcholine and phosphatidylethanolamine. Phosphatidylcholine levels were higher in those with mTBI compared to controls (p < 0.05), while lower concentration of phosphatidylethanolamine was seen in those with mTBI compared to controls (p < 0.05). Phosphatidylinositol-3,4,5-trisphosphate was significant in those with mTBI compared to controls (n = 10) based on improved (n = 6) versus worsened (n = 8) outcomes from 3 to 6 months. CONCLUSION: We identified plasma metabolites related to phospholipid metabolism in older adults following mTBI and associated with long-term functional outcome. These findings may underly pathological mechanisms of outcome differences in older adults who experience mTBI.

Impact of Age on Plasma Inflammatory Biomarkers in the 6 Months Following Mild Traumatic Brain Injury.

OBJECTIVE: To compare plasma inflammatory biomarker concentrations to 6 months in young and older adults with and without mild traumatic brain injury (TBI). SETTING: Level 1 trauma center. PARTICIPANTS: Younger (21-54 years) and older (55+) adults diagnosed with mild TBI along with age-/sex-matched noninjured controls (n = 313). DESIGN: Prospective cohort study. MAIN MEASURES: Multiplex assays were used to quantify concentrations of selected plasma inflammatory markers at day 0, months 1 and 6. RESULTS: Persistent aging-related differences were found between control groups in concentrations of 4 cytokines up to 6 months. At day 0, interleukin-6 (IL-6), IL-8, and fractalkine were higher in the older TBI compared with older control as well as the younger TBI groups, while IL-10 was higher in older TBI compared with controls. At month 1, significantly higher concentrations of IL-8, fractalkine, and tumor necrosis factor-α (TNF-α) were seen. At 6 months postinjury, significantly higher concentrations of IL-6 and IL-8 were seen, while a lower concentration of IL-7 was found in older versus younger TBI groups. CONCLUSION: The neuroinflammatory signature that accompanies mild TBI in older adults differs from that of younger adults. The differences seen are notable for their roles in neutrophil attraction (IL-8), neuronal-microglial-immune cell interactions (fractalkine), and chronic inflammation (IL-6).

Early acid/base and electrolyte changes in permanent middle cerebral artery occlusion: Aged male and female rats.

BACKGROUND: Early changes in acid/base and electrolyte concentrations could provide insights into the development of neuropathology at the onset of stroke. We evaluated associations between acid/base and electrolyte concentrations, and outcomes in permanent middle cerebral artery occlusion (pMCAO) model. METHODS: 18-month-old male and female Sprague-Dawley rats underwent pMCAO. Pre-, post- (7 min after occlusion), and at 72 hr of pMCAO venous blood samples provided pH, carbon dioxide, oxygen, glucose, hematocrit, hemoglobin, and electrolyte values of ionized calcium, potassium, and sodium. Multiple linear regression determined predictors of infarct and edema volumes from these values, Kaplan-Meier curve analyzed morality between males and females at 72 hr, and a Cox regression model was used to determine predictors for mortality. RESULTS: Analysis indicated significant differences in acid/base balance and electrolyte levels in aged rats not dependent on sex between the three time points in the pMCAO model. Changes in pH (from pre- to post and post- to 72 hr) and changes in sodium and ionized calcium (from post- to 72 hr) were predictors of infarct volume and edema volume, respectively. Cox Regression revealed there is a 3.25 times increased risk for mortality based on changes in bicarbonate (pre- to post-MCAO). CONCLUSIONS: These early venous blood changes in acid/base balance and electrolytes can be used to predict stroke outcomes in our rat model of stroke. This study provides potential biomarkers to be examined in the human condition that could provide profound prognostic tools for stroke patients.

Evaluation of sex differences in acid/base and electrolyte concentrations in acute large vessel stroke.

INTRODUCTION: Ischemic stroke is the one of the most severe and debilitating diseases, and despite animal models, there is much to learn about the neuropathology in humans in a way that could inform the development of therapies. We have developed a protocol to collect and evaluate arterial blood immediately distal and proximal from the removed intracranial thrombus during mechanical thrombectomy. These samples provide a unique resource in evaluating acute changes in acid/base and electrolyte concentrations at the time of ischemic stroke. The purpose of this study was to compare acid/base and electrolytes obtained proximal and distal to the occluded intracranial thrombi between male and female acute ischemic stroke subjects at the time of thrombectomy; and to determine whether arterial blood gas values predict outcomes in male and female subjects. METHODS: We analyzed the first 49 subjects (age = 67 ±â€¯15.0, 21 males) in the BACTRAC registry. We compared arterial blood gas of blood distal versus proximal to the thrombus during thrombectomy which provided acid/base levels (pH, pCO2, pO2, BD, HCO3-) and electrolyte values (iCa2+, K+, and Na+). Comparisons were evaluated by one-way repeated measures ANOVA (p < .05). Moderated multiple regression with an interaction term of sex determined predictors of infarct volume, edema volume, and infarct time. RESULTS: In general, distal intracranial luminal blood sample showed a compensated metabolic acidosis with an elevated oxygen concentration in both blood samples. Analysis indicated several significant differences in the proximal blood samples between sexes (pH, pCO2, and K+). Bicarbonate and base deficit were predictors of infarct time specifically in female subjects. DISCUSSION AND CONCLUSION: Acid/base and electrolyte response to ischemic conditions differ between men and women, and these early changes could be used to predict local acid/base changes and how they develop differently in men and women during ischemia. These findings provide a novel insight into the pathology of large vessel stroke in humans, particularly potential variations based on sex.

Acid-Base and Electrolyte Changes Drive Early Pathology in Ischemic Stroke.

Emergent large vessel occlusion accounts for 20-40% of ischemic strokes and is the most debilitating form of stroke. Some of the earliest changes in response to ischemic stroke occur in blood gases and electrolytes. These biochemical changes occur within minutes after occlusion in experimental models of stroke and can be utilized to predict stroke outcomes. The majority of ELVO stroke patients are middle-aged to elderly and are of both sexes, revealing that there is an age and sex mismatch between ischemic stroke patients and animal models, since most experimental studies use young male rats. Rethinking of the animal models should be considered, especially in encouraging the use of aged male and female rats with comorbidities to more closely mirror human populations. Mechanical thrombectomy provides a unique opportunity for researchers to further this work by expanding the collection and analysis of blood samples that are adjacent to the thrombus. To understand the complexity of stroke, researchers can analyze these tissues for different molecular targets that occur in response to ischemic stroke. This information may aid in the reduction of symptom burden for individuals diagnosed with ischemic stroke. Investigators should also focus on data from ischemic stroke patients and attempt to discover target molecules and then in animal models to establish mechanism, which will aid in the development of new stroke therapies. This review discusses the translation of these studies to the human patient to develop the capability to predict stroke outcomes. Future studies are needed to identify molecular targets to predict the risk of worsened long-term outcomes and/or increased risk for mortality.

The Blood And Clot Thrombectomy Registry And Collaboration (BACTRAC) protocol: novel method for evaluating human stroke.

BACKGROUND: Ischemic stroke research faces difficulties in translating pathology between animal models and human patients to develop treatments. Mechanical thrombectomy, for the first time, offers a momentary window into the changes occurring in ischemia. We developed a tissue banking protocol to capture intracranial thrombi and the blood immediately proximal and distal to it. OBJECTIVE: To develop and share a reproducible protocol to bank these specimens for future analysis. METHODS: We established a protocol approved by the institutional review board for tissue processing during thrombectomy (www.clinicaltrials.gov NCT03153683). The protocol was a joint clinical/basic science effort among multiple laboratories and the NeuroInterventional Radiology service line. We constructed a workspace in the angiography suite, and developed a step-by-step process for specimen retrieval and processing. RESULTS: Our protocol successfully yielded samples for analysis in all but one case. In our preliminary dataset, the process produced adequate amounts of tissue from distal blood, proximal blood, and thrombi for gene expression and proteomics analyses. We describe the tissue banking protocol, and highlight training protocols and mechanics of on-call research staffing. In addition, preliminary integrity analyses demonstrated high-quality yields for RNA and protein. CONCLUSIONS: We have developed a novel tissue banking protocol using mechanical thrombectomy to capture thrombus along with arterial blood proximal and distal to it. The protocol provides high-quality specimens, facilitating analysis of the initial molecular response to ischemic stroke in the human condition for the first time. This approach will permit reverse translation to animal models for treatment development.

Expression of Cytokines and Chemokines as Predictors of Stroke Outcomes in Acute Ischemic Stroke.

Introduction: Ischemic stroke remains one of the most debilitating diseases and is the fifth leading cause of death in the US. The ability to predict stroke outcomes within the acute period of stroke would be essential for care planning and rehabilitation. The Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC; clinicaltrials.gov NCT03153683) study collects arterial blood immediately distal and proximal to the intracranial thrombus at the time of mechanical thrombectomy. These blood samples are an innovative resource in evaluating acute gene expression changes at the time of ischemic stroke. The purpose of this study was to identify inflammatory genes and important immune factors during mechanical thrombectomy for emergent large vessel occlusion (ELVO) and which patient demographics were predictors for stroke outcomes (infarct and/or edema volume) in acute ischemic stroke patients. Methods: The BACTRAC study is a non-probability sampling of male and female subjects (≥18 year old) treated with mechanical thrombectomy for ELVO. We evaluated 28 subjects (66 ± 15.48 years) relative concentrations of mRNA for gene expression in 84 inflammatory molecules in arterial blood distal and proximal to the intracranial thrombus who underwent thrombectomy. We used the machine learning method, Random Forest to predict which inflammatory genes and patient demographics were important features for infarct and edema volumes. To validate the overlapping genes with outcomes, we perform ordinary least squares regression analysis. Results: Machine learning analyses demonstrated that the genes and subject factors CCR4, IFNA2, IL-9, CXCL3, Age, T2DM, IL-7, CCL4, BMI, IL-5, CCR3, TNFα, and IL-27 predicted infarct volume. The genes and subject factor IFNA2, IL-5, CCL11, IL-17C, CCR4, IL-9, IL-7, CCR3, IL-27, T2DM, and CSF2 predicted edema volume. The overlap of genes CCR4, IFNA2, IL-9, IL-7, IL-5, CCR3, and IL-27 with T2DM predicted both infarct and edema volumes. These genes relate to a microenvironment for chemoattraction and proliferation of autoimmune cells, particularly Th2 cells and neutrophils. Conclusions: Machine learning algorithms can be employed to develop prognostic predictive biomarkers for stroke outcomes in ischemic stroke patients, particularly in regard to identifying acute gene expression changes that occur during stroke.

Translational Evaluation of Acid/Base and Electrolyte Alterations in Rodent Model of Focal Ischemia.

BACKGROUND AND PURPOSE: Acid/base and electrolytes could provide clinically valuable information about cerebral infarct core and penumbra. We evaluated associations between acid/base and electrolyte changes and outcomes in 2 rat models of stroke, permanent, and transient middle cerebral artery occlusion. METHODS: Three-month old Sprague-Dawley rats underwent permanent or transient middle cerebral artery occlusion. Pre- and post-middle cerebral artery occlusion venous samples for permanent and transient models provided pH, carbon dioxide, oxygen, glucose, and electrolyte values of ionized calcium, potassium, and sodium. Multiple regression determined predictors of infarct volume from these values, and Kaplan-Meier curve analyzed morality between permanent and transient middle cerebral artery occlusion models. RESULTS: Analysis indicated significant differences in the blood gas and electrolytes between pre- to post-middle cerebral artery occlusion. A decrease in pH and sodium with increases in carbon dioxide, potassium, ionized calcium, and glucose changes were found in both middle cerebral artery occlusion models; while hematocrit and hemoglobin were significant in the transient model. pH and ionized calcium were predictors of infarct volume in the permanent model, as changes in pH and ionized calcium decreased, infarct volume increased. CONCLUSIONS: There are acute changes in acid/base balance and electrolytes during stroke in transient and permanent rodent models. Additionally, we found pH and ionized calcium changes predicted stroke volume in the permanent middle cerebral artery occlusion model. These preliminary findings are novel, and warrant further exploration in human conditions.

Natural variation in life history and aging phenotypes is associated with mitochondrial DNA deletion frequency in Caenorhabditis briggsae.

BACKGROUND: Mutations that impair mitochondrial functioning are associated with a variety of metabolic and age-related disorders. A barrier to rigorous tests of the role of mitochondrial dysfunction in aging processes has been the lack of model systems with relevant, naturally occurring mitochondrial genetic variation. Toward the goal of developing such a model system, we studied natural variation in life history, metabolic, and aging phenotypes as it relates to levels of a naturally-occurring heteroplasmic mitochondrial ND5 deletion recently discovered to segregate among wild populations of the soil nematode, Caenorhabditis briggsae. The normal product of ND5 is a central component of the mitochondrial electron transport chain and integral to cellular energy metabolism. RESULTS: We quantified significant variation among C. briggsae isolates for all phenotypes measured, only some of which was statistically associated with isolate-specific ND5 deletion frequency. We found that fecundity-related traits and pharyngeal pumping rate were strongly inversely related to ND5 deletion level and that C. briggsae isolates with high ND5 deletion levels experienced a tradeoff between early fecundity and lifespan. Conversely, oxidative stress resistance was only weakly associated with ND5 deletion level while ATP content was unrelated to deletion level. Finally, mean levels of reactive oxygen species measured in vivo showed a significant non-linear relationship with ND5 deletion level, a pattern that may be driven by among-isolate variation in antioxidant or other compensatory mechanisms. CONCLUSIONS: Our findings suggest that the ND5 deletion may adversely affect fitness and mitochondrial functioning while promoting aging in natural populations, and help to further establish this species as a useful model for explicit tests of hypotheses in aging biology and mitochondrial genetics.