Publications by authors named "Patrick D Lyden"

Introduction: Given the close interactions between the retina and the brain, retinal amyloid imaging may serve as a diagnostic and prognostic tool for Alzheimer's disease and related dementias. This retrospective study investigated multivariable associations between retinal perivascular amyloid and cognitive domains.

Methods: Integrated analysis of retinal perivascular amyloid imaging, neuropsychological assessment, and brain magnetic resonance imaging in adults with and without cognitive impairment (N = 26; mean age: 65 ± 7 years; 50% female).

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Background: The SPAN (Stroke Preclinical Assessment Network) is a confirmatory multicenter trial network to test cerebroprotective interventions in experimental acute stroke. In a first-of-its-kind trial, SPAN tested 6 interventions in a rodent model of transient focal ischemic stroke. Here, we report the efficacy of fasudil, an isoform-nonselective rho-associated kinase inhibitor, on primary and secondary outcomes in the SPAN trial.

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Penetrating brain injuries (PBI) constitute a significant subset of traumatic brain injuries, characterized by high morbidity and mortality due to their unique pathophysiological mechanisms. Despite its clinical prevalence in civilian and military settings, progress in translational research remains limited due to a lack of well-characterized pre-clinical models that accurately replicate human PBI. Existing models often fail to adequately simulate critical aspects such as ballistic dynamics, tissue cavitation, and secondary injury cascades, limiting their translational relevance and hindering therapeutic advancements.

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Background: The SPAN (Stroke Preclinical Assessment Network) is a confirmatory trial platform to test the efficacy and safety of candidate cerebroprotective interventions in acute stroke. As the largest multicenter preclinical stroke trial to date, the SPAN1 trial (first SPAN) prospectively captured many biological and procedural variables, revealing a high degree of heterogeneity introduced by the multicenter approach that may impact stroke outcomes. Here, we examined the biological and procedural predictors of tissue and neurological outcomes after focal cerebral ischemic stroke in rats.

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Background: Past failures in translating stroke cerebroprotection provoked calls for a more rigorous methodological approach, leading to the stroke preclinical assessment network SPAN (Stroke Preclinical Assessment Network), where uric acid (UA) treatment exceeded a prespecified efficacy boundary for the primary functional outcome. Still, successful translation to humans requires confirmation of the effect of UA across key biological variables relevant to patients with stroke.

Methods: We measured the effects of intravenous UA treatment (16 mg/kg) versus intravenous saline in groups of animals enrolled in the SPAN network with diverse comorbidities, sex, and age.

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Cerebral blood flow is a critical metric for cerebrovascular monitoring, with applications in stroke detection, brain injury evaluation, aging, and neurological disorders. Non-invasively measuring cerebral blood dynamics is challenging due to the scalp and skull, which obstruct direct brain access and contain their own blood dynamics that must be isolated. We developed an aggregated seven-channel speckle contrast optical spectroscopy system to measure blood flow and blood volume non-invasively.

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Stroke poses a significant global health threat, with millions affected annually, leading to substantial morbidity and mortality. Current stroke risk assessment for the general population relies on markers such as demographics, blood tests, and comorbidities. A minimally invasive, clinically scalable, and cost-effective way to directly measure cerebral blood flow presents an opportunity.

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Direct oral anticoagulants are the primary stroke prevention option in patients with atrial fibrillation. Anticoagulant use before stroke, however, might inhibit clinician comfort with thrombolysis if a stroke does occur. Resuming anticoagulants after ischemic stroke is also problematic for fear of hemorrhage.

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Background And Purpose: Post thrombolytic intracerebral hemorrhage (ICH) is associated with higher rate of death or disability in acute ischemic stroke patients. We investigated the relationship between post thrombolytic ICH volume and change in volume and death or disability at 90 days in acute ischemic stroke patients.

Methods: We analyzed 110 patents recruited in the Safety Evaluation of 3K3A-APC in Ischemic Stroke (RHAPSODY) trial who received intravenous tissue plasminogen activator (tPA) followed by mechanical thrombectomy (if indicated) and 3K3A-APC or placebo.

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Stroke poses a significant global health threat, with millions affected annually, leading to substantial morbidity and mortality. Current stroke risk assessment for the general population relies on markers such as demographics, blood tests, and comorbidities. A minimally invasive, clinically scalable, and cost-effective way to directly measure cerebral blood flow presents an opportunity.

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Early evidence-based medical interventions to improve patient outcomes after traumatic brain injury (TBI) are lacking. In patients admitted to the ICU after TBI, optimization of nutrition is an emerging field of interest. Specialized enteral nutrition (EN) formulas that include immunonutrition containing omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been developed and are used for their proposed anti-inflammatory and proimmune properties; however, their use has not been rigorously studied in human TBI populations.

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Background: The SPAN trial (Stroke Preclinical Assessment Network) is the largest preclinical study testing acute stroke interventions in experimental focal cerebral ischemia using endovascular filament middle cerebral artery occlusion (MCAo). Besides testing interventions against controls, the prospective design captured numerous biological and procedural variables, highlighting the enormous heterogeneity introduced by the multicenter structure that might influence stroke outcomes. Here, we leveraged the unprecedented sample size achieved by the SPAN trial and the prospective design to identify the biological and procedural variables that affect experimental stroke outcomes in transient endovascular filament MCAo.

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Article Synopsis
  • The study explores the connection between amyloidosis in retinal blood vessels and cognitive impairment, especially in Alzheimer's disease (AD), utilizing a new image processing method for analyzing retinal amyloid plaque distribution in individuals with varying cognitive abilities.
  • Results showed higher levels of amyloid plaques near retinal arteries compared to veins, with increased plaque counts linked to cognitive decline and neuroimaging metrics in cognitively impaired individuals.
  • The findings suggest that retinal imaging could serve as a predictive tool for cognitive decline and AD progression, highlighting the need for larger studies to better understand the relationship between retinal amyloid deposition and cognitive health over time.
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Article Synopsis
  • * Embolic stroke of undetermined source (ESUS) is a subgroup of cryptogenic strokes where embolism is thought to be the cause, but there's no established treatment for prevention due to the lack of confirmed causes.
  • * Advanced MRI techniques can help identify potential causes of these strokes, like atherosclerosis or hidden blood clots, and the review also discusses future advancements in MRI technology for better diagnoses.
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Introduction: The vascular contribution to Alzheimer's disease (AD) is tightly connected to cognitive performance across the AD continuum. We topographically describe retinal perivascular amyloid plaque (AP) burden in subjects with normal or impaired cognition.

Methods: Using scanning laser ophthalmoscopy, we quantified retinal peri-arteriolar and peri-venular curcumin-positive APs in the first, secondary and tertiary branches in twenty-eight subjects.

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Background: The National Institutes of Health Stroke Scale is a widely accepted tool for structured graded neurological examination of stroke or suspected stroke in the hyperacute setting. Concerns have arisen about the use of its picture stimuli in a contemporary and global health context. Here, we present new stimuli prepared to serve the needs of stroke providers worldwide: the precarious painter image description and updated objects for naming.

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Traumatic brain injury (TBI) is a common diagnosis requiring acute hospitalization. Long-term, TBI is a significant source of health and socioeconomic impact in the United States and globally. The goal of clinicians who manage TBI is to prevent secondary brain injury.

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Background: Early evidence-based medical interventions to improve patient outcomes after traumatic brain injury (TBI) are lacking. In patients admitted to the ICU after TBI, optimization of nutrition is an emerging field of interest. Specialized enteral nutrition (EN) formulas that include immunonutrition containing omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been developed and are used for their proposed anti-inflammatory and pro-immune properties; however, their use has not been rigorously studied in human TBI populations.

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Article Synopsis
  • The STAIR XII workshop focused on improving neuroimaging techniques for diagnosing acute ischemic stroke, bringing together experts from academia, industry, and government to identify key priorities.
  • Ten critical areas were outlined for advancements, including enhancing imaging at stroke centers, refining clot analysis, and establishing criteria to predict treatment response.
  • Despite progress in imaging for stroke treatment, significant challenges persist, highlighting the need for collaboration among academics, industry, and regulators to enhance technologies and improve patient outcomes.
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Emerging science continues to establish the detrimental effects of malnutrition in acute neurological diseases such as traumatic brain injury, stroke, status epilepticus and anoxic brain injury. The primary pathological pathways responsible for secondary brain injury include neuroinflammation, catabolism, immune suppression and metabolic failure, and these are exacerbated by malnutrition. Given this, there is growing interest in novel nutritional interventions to promote neurological recovery after acute brain injury.

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Article Synopsis
  • - The Stroke Preclinical Assessment Network (SPAN) was created to address concerns about the reliability of preclinical testing for new stroke treatments, following recent failures in clinical trials.
  • - SPAN conducted a rigorous multi-laboratory trial using various animal models to assess candidate treatments in a controlled manner, ensuring aspects like treatment masking and randomization were properly implemented.
  • - By following a standardized protocol across six labs and successfully enrolling a large number of animals, SPAN aims to enhance reproducibility in preclinical research, potentially applying its framework to other medical research areas.
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The Stroke Treatment Academic Industry Roundtable (STAIR) convened a session and workshop regarding enrollment in acute stroke trials during the STAIR XII meeting on March 22, 2023. This forum brought together stroke physicians and researchers, members of the National Institute of Neurological Disorders and Stroke, industry representatives, and members of the US Food and Drug Administration to discuss the current status and opportunities for improving enrollment in acute stroke trials. The workshop identified the most relevant issues impacting enrollment in acute stroke trials and addressed potential action items for each.

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Despite a current emphasis on equity in stroke care, one of the most common stroke assessment tools that is used both nationally and internationally, includes an anachronistic image that projects cultural, linguistic, and socioeconomic bias. This image, titled The Cookie Theft picture, is included in the National Institutes of Health Stroke Scale and was originally developed in 1972. Now, 50 years later, it does not reflect our current diverse, linguistically rich, and multicultural patient population.

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Despite the high mortality and disability associated with traumatic brain injury (TBI), effective pharmacologic treatments are lacking. Of emerging interest, bioactive lipids, including specialized pro-resolving lipid mediators of inflammation (SPMs), act to attenuate inflammation after injury resolution. The SPM lipidome may serve as a biomarker of disease and predictor of clinical outcomes, and the use of exogenous SPM administration represents a novel therapeutic strategy for TBI.

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