Evaluation of Exploratory Fluid Biomarker Results from a Phase 1 Senolytic Trial in Mild Alzheimer's Disease.

Senescent cell accumulation contributes to the progression of age-related disorders including Alzheimer's disease (AD). Clinical trials evaluating senolytics, drugs that clear senescent cells, are underway, but lack standardized outcome measures. Our team recently published data from the first open-label trial to evaluate senolytics (dasatinib plus quercetin) in AD. After 12-weeks of intermittent treatment, we reported brain exposure to dasatinib, favorable safety and tolerability, and modest post-treatment changes in cerebrospinal fluid (CSF) inflammatory and AD biomarkers using commercially available assays. Herein, we present more comprehensive exploratory analyses of senolytic associated changes in AD relevant proteins, metabolites, lipids, and transcripts measured across blood, CSF, and urine. These analyses included mass spectrometry for precise quantification of amyloid beta (Aß) and tau in CSF; immunoassays to assess senescence associated secretory factors in plasma, CSF, and urine; mass spectrometry analysis of urinary metabolites and lipids in blood and CSF; and transcriptomic analyses relevant to chronic stress measured in peripheral blood cells. Levels of Aß and tau species remained stable. Targeted cytokine and chemokine analyses revealed treatment-associated increases in inflammatory plasma fractalkine and MMP-7 and CSF IL-6. Urinary metabolites remained unchanged. Modest treatment-associated lipid profile changes suggestive of decreased inflammation were observed both peripherally and centrally. Blood transcriptomic analysis indicated downregulation of inflammatory genes including FOS, FOSB, IL1ß, IL8, JUN, JUNB, PTGS2. These data provide a foundation for developing standardized outcome measures across senolytic studies and indicate distinct biofluid-specific signatures that will require validation in future studies. ClinicalTrials.gov: NCT04063124.

Senolytic therapy in mild Alzheimer's disease: a phase 1 feasibility trial.

Cellular senescence contributes to Alzheimer's disease (AD) pathogenesis. An open-label, proof-of-concept, phase I clinical trial of orally delivered senolytic therapy, dasatinib (D) and quercetin (Q), was conducted in early-stage symptomatic patients with AD to assess central nervous system (CNS) penetrance, safety, feasibility and efficacy. Five participants (mean age = 76 + 5 years; 40% female) completed the 12-week pilot study. D and Q levels in blood increased in all participants (12.7-73.5 ng ml-1 for D and 3.29-26.3 ng ml-1 for Q). In cerebrospinal fluid (CSF), D levels were detected in four participants (80%) ranging from 0.281 to 0.536 ml-1 with a CSF to plasma ratio of 0.422-0.919%; Q was not detected. The treatment was well-tolerated, with no early discontinuation. Secondary cognitive and neuroimaging endpoints did not significantly differ from baseline to post-treatment further supporting a favorable safety profile. CSF levels of interleukin-6 (IL-6) and glial fibrillary acidic protein (GFAP) increased (t(4) = 3.913, P = 0.008 and t(4) = 3.354, P = 0.028, respectively) with trending decreases in senescence-related cytokines and chemokines, and a trend toward higher Aß42 levels (t(4) = -2.338, P = 0.079). In summary, CNS penetrance of D was observed with outcomes supporting safety, tolerability and feasibility in patients with AD. Biomarker data provided mechanistic insights of senolytic effects that need to be confirmed in fully powered, placebo-controlled studies. ClinicalTrials.gov identifier: NCT04063124 .

Senolytic therapy to modulate the progression of Alzheimer's Disease (SToMP-AD) - Outcomes from the first clinical trial of senolytic therapy for Alzheimer's disease.

Cellular senescence has been identified as a pathological mechanism linked to tau and amyloid beta (Aß) accumulation in mouse models of Alzheimer's disease (AD). Clearance of senescent cells using the senolytic compounds dasatinib (D) and quercetin (Q) reduced neuropathological burden and improved clinically relevant outcomes in the mice. Herein, we conducted a vanguard open-label clinical trial of senolytic therapy for AD with the primary aim of evaluating central nervous system (CNS) penetrance, as well as exploratory data collection relevant to safety, feasibility, and efficacy. Participants with early-stage symptomatic AD were enrolled in an open-label, 12-week pilot study of intermittent orally-delivered D+Q. CNS penetrance was assessed by evaluating drug levels in cerebrospinal fluid (CSF) using high performance liquid chromatography with tandem mass spectrometry. Safety was continuously monitored with adverse event reporting, vitals, and laboratory work. Cognition, neuroimaging, and plasma and CSF biomarkers were assessed at baseline and post-treatment. Five participants (mean age: 76±5 years; 40% female) completed the trial. The treatment increased D and Q levels in the blood of all participants ranging from 12.7 to 73.5 ng/ml for D and 3.29-26.30 ng/ml for Q. D levels were detected in the CSF of four participants ranging from 0.281 to 0.536 ng/ml (t(4)=3.123, p=0.035); Q was not detected. Treatment was well-tolerated with no early discontinuation and six mild to moderate adverse events occurring across the study. Cognitive and neuroimaging endpoints did not significantly differ from baseline to post-treatment. CNS levels of IL-6 and GFAP increased from baseline to post-treatment (t(4)=3.913, p=008 and t(4)=3.354, p=0.028, respectively) concomitant with decreased levels of several cytokines and chemokines associated with senescence, and a trend toward higher levels of Aß42 (t(4)=-2.338, p=0.079). Collectively the data indicate the CNS penetrance of D and provide preliminary support for the safety, tolerability, and feasibility of the intervention and suggest that astrocytes and Aß may be particularly responsive to the treatment. While early results are promising, fully powered, placebo-controlled studies are needed to evaluate the potential of AD modification with the novel approach of targeting cellular senescence.

PET imaging of mGluR5 in Alzheimer's disease.

BACKGROUND: Metabotropic glutamate subtype 5 receptors (mGluR5) modulate synaptic transmission and may constitute an important therapeutic target in Alzheimer's disease (AD) by mediating the synaptotoxic action of amyloid-ß oligomers. We utilized the positron emission tomography (PET) radioligand [18F]FPEB to investigate mGluR5 binding in early AD. METHODS: Sixteen individuals with amnestic mild cognitive impairment (MCI) due to AD or mild AD dementia who were positive for brain amyloid were compared to 15 cognitively normal (CN) participants who were negative for brain amyloid. Diagnostic groups were well balanced for age, sex, and education. Dynamic PET scans were acquired for 60 min, starting at 60 min after the initial administration of up to 185 MBq of [18F]FPEB using a bolus-plus-constant-infusion method (Kbol = 190 min). Equilibrium modeling with a cerebellum reference region was used to estimate [18F]FPEB binding (BPND) to mGluR5. Analyses were performed with and without corrections for gray matter atrophy and partial volume effects. RESULTS: Linear mixed model analysis demonstrated a significant effect of group (p = 0.011) and the group × region interaction (p = 0.0049) on BPND. Post hoc comparisons revealed a significant reduction (43%) in mGluR5 binding in the hippocampus of AD (BPND = 0.76 ± 0.41) compared to CN (BPND = 1.34 ± 0.58, p = 0.003, unpaired t test) participants, and a nonsignificant trend for a reduction in a composite association cortical region in AD (BPND = 1.57 ± 0.25) compared to CN (BPND = 1.86 ± 0.63, p = 0.093) participants. Exploratory analyses suggested additional mGluR5 reductions in the entorhinal cortex and parahippocampal gyrus in the AD group. In the overall sample, hippocampal mGluR5 binding was associated with episodic memory scores and global function. CONCLUSIONS: [18F]FPEB-PET revealed reductions in hippocampal mGluR5 binding in early AD. Quantification of mGluR5 binding in AD may expand our understanding of AD pathogenesis and accelerate the development of novel biomarkers and treatments.

An Overview of Primary Dementias as Clinicopathological Entities.

Dementia is a state of cognitive dysfunction which leads to functional decline. It is a syndrome caused by several medical and neurological causes, but most cases of dementia are due to "primary dementias." Primary dementias are neurological diseases whose manifestations are predominantly cognitive. Most primary dementias are caused by neurodegenerative proteinopathies where an accumulation of misfolded proteins leads to neuronal loss, neuroinflammation and glial reaction. Each proteinopathy is characterized by the type of protein implicated in its pathophysiology. Neurodegenerative dementias include the most prevalent cause of dementia-Alzheimer's disease-as well as Lewy body dementia, Parkinson's disease dementia, frontotemporal dementias, and prion diseases. Vascular dementia, especially small vessel disease, though not a neurodegenerative condition, is often grouped together with primary dementias. Each type of proteinopathy, characterized by the location and nature of misfolded protein accumulation, may correspond to a particular clinical phenotype. The correspondence between pathologies and clinical phenotypes is not exclusive, and there is a large degree of overlap. Although in the research setting the clinicopathological construct is on the wane, in the clinic it is the most practical way of approaching primary dementias. In this article, we introduce the clinicopathological construct, the understanding of which will form the basis of the other articles in this volume.

A Comprehensive Update on Treatment of Dementia.

Treatment of dementias represents an important but relatively neglected part of neurological care of the elderly population. Individual therapeutic interventions may make only small changes to the quality of life of individuals afflicted with dementia, but when used in combination these interventions synergize and can make a significant difference. Additionally, given the societal scale of the problem of dementia care, the overall impact, in economic and sociological terms, of such therapies is of consequence. Presently there are no disease-modifying treatments for any of the neurodegenerative dementias. Instead, the clinician has several therapeutic tools to mitigate cognitive and behavioral consequences of dementias. There are also strategies to minimize harm to patients with dementia. In this article, we aim to review these tools and place them in the greater context of dementia care.

A Multifactor Approach to Mild Cognitive Impairment.

Mild cognitive impairment (MCI) represents an intermediate stage between normal cognition and dementia. Individuals with MCI are at increased risk of conversion to dementia, and the rate of progression of MCI to dementia is dependent on age, gender, and education. MCI may be diagnosed using neuropsychological criteria using cut-offs representing decrements in cognition, or using criteria to assess for a decline in functional status. The ability to determine the status of dementia-related biomarkers has allowed for better staging and prognostication in different forms of MCI. MCI is now recognized as a significant target stage for future therapies. These future therapies aim to reduce the rate of conversion of individuals with MCI to dementia. In this article, we review different conceptions of MCI, the diagnosis and prognostication of MCI, and presently available management approaches for this condition.

Interpretation of Biomarker Data in Diagnosis of Primary Dementias.

In the last few years, an improved understanding of dementia biomarkers has significantly increased the diagnostic accuracy for dementias. The National Institutes of Health Biomarkers Definitions Working Group defines a biomarker as "a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention." In the field of dementia, a biomarker is a biological measure pointing to a specific dementing pathology. Dementia biomarkers may also serve as surrogates for disease progression and as endpoints in clinical trials. Dementia biomarkers are best characterized for Alzheimer's disease, which is the most common form of primary dementia. The current "biological" conception of Alzheimer's disease is based on consideration of three biomarkers: amyloid, tau, and "neurodegeneration." The status of these biomarkers may be determined by cerebrospinal fluid clinical chemistry or imaging. Biomarkers for other primary dementias are less reliable and rely chiefly on structural and functional imaging. When appropriate, genetic testing may help with diagnostic certainty in hereditary forms of dementia.

Dementia in Essential Tremor: A Visual Record.

Background: Research studies have shown an association between essential tremor (ET) and dementia, although dementia in ET is not often regarded as a clinically important issue. Phenomenology Shown: We present three tangible visual records of patients with ET who have developed concurrent, comorbid dementia. Educational Value: ET is a risk factor for dementia. This non-motor feature of the disease has substantial effects on the lives of patients and their families.

A Neurology Clerkship Curriculum Using Video-Based Lectures and Just-in-Time Teaching (JiTT).

Introduction: Just-in-time teaching is an educational strategy that involves tailoring in-session learning activities based on student performance in presession assessments. We implemented this strategy in a third-year neurology clerkship. Methods: Linked to core neurology clerkship lectures, eight brief video-based lectures and knowledge assessments were developed. Students watched videos and completed multiple-choice questions, and results were provided to faculty, who were given the opportunity to adjust the in-person lecture accordingly. Feedback was obtained by surveys of students and faculty lecturers and from student focus groups and faculty. Student performance on the end-of-clerkship examination was analyzed. Results: Between October 2016 and April 2017, 135 students participated in the curriculum, and 56 students (41.5%) responded to the surveys. Most students agreed or strongly agreed that the new curriculum enhanced their learning and promoted their sense of responsibility in learning the content. Faculty agreed that this pedagogy helped prepare students for class. Most students watched the entire video-based lecture, although there was a trend toward decreased audience retention with longer lectures. There were no significant changes in performance on the end-of-clerkship examination after implementation of just-in-time teaching. In focus groups, students emphasized the importance of tying just-in-time teaching activities to the lecture and providing video-based lectures well in advance of the lectures. Discussion: Just-in-time teaching using video-based lectures is an acceptable and feasible method to augment learning during a neurology clinical clerkship. We believe this method could be used in other neurology clerkships with similar success.

The head that wears the crown: Henry VIII and traumatic brain injury.

Henry VIII of England is one of the most controversial figures in European history. He was born on 28 June 1491 as the second son of Henry VII and Elizabeth of York and became the heir to the English throne after his elder brother died prematurely. A contradictory picture of Henry's character emerges from history: the young Henry was a vigorous, generous and intelligent king who saw early military and naval successes. In contrast, in his later years he became cruel, petty and tyrannical. His political paranoia and military misjudgements are in direct contrast to his earlier successes and promise. Several hypotheses have been put forward regarding his transformation from a renaissance king to a later medieval tyrant, including endocrinopathies, psychiatric illnesses and traumatic brain injury. In this paper we examine the historical evidence linking the change in Henry's personality and health problems to traumatic brain injury. To our knowledge this is the first systematic neurological study of traumatic brain injury in Henry VIII.

A Phase I-II, Open-Label, Multicenter Trial to Determine the Dosimetry and Safety of 99mTc-Sestamibi in Pediatric Subjects.

UNLABELLED: Myocardial perfusion imaging has long been used off label by practitioners attending for children with cardiac aliments. To provide clinicians with evidence-based dosage recommendation, a phase I-II, open-label, nonrandomized, multicenter trial was therefore designed using (99m)Tc-sestamibi in pediatric subjects (registered under www.clinicaltrials.gov identifier no. NCT00162045). METHODS: Safety and pharmacokinetic data were collected from 78 subjects using either a 1-d imaging protocol (3.7-7.4 MBq/kg, followed by 11.1 MBq/kg) or a 2-d protocol (7.4 MBq/kg for both rest and stress). Anterior and posterior planar images were collected at 15 min, 1.5 h, 4 h, and 8 h. Blood and urine samples were collected at predetermined times. RESULTS: Subjects included 39 children (mean age ± SD, 8.5 ± 2.04 y) and 39 adolescents (mean age ± SD, 13.6 ± 1.39 y). Mean estimated organ-absorbed doses to the upper large intestine, small intestine, gallbladder wall, and lower large intestines were 0.082, 0.043, 0.042, and 0.035 mSv/MBq, respectively. All patients tolerated the radiotracer without serious adverse effects. Significant differences were observed in the liver, upper large intestine contents, and small intestine contents between rest and stress imaging. The effective dose equivalent and effective dose averages were lower in adolescents than younger children (0.011 and 0.019 mSv/MBq, respectively; P < 0.0001). Percentage injected doses (%IDs) corrected for radioactive decay in all dosimetry-evaluable subjects at 15 min and 4 h were 1.9% and 1.2% in the myocardium. Similarly in the lungs, the %ID for all dosimetry-evaluable subjects was 4.9% at 15 min after injection. At rest, the %ID in the liver decreased from a maximum of about 26% at 15 min to less than 9% at 90 min. With stress, values decreased from 15% to 7%, respectively. CONCLUSION: The estimates of radiation dosimetry, pharmacokinetic parameters, and safety profile in this study population are similar to published studies based on body-mass extrapolations from studies in adults. As such, applying current (99m)Tc-sestamibi dosing regimens for 1- and 2-d protocols based on those extrapolations will result in the expected radiation dose in children and adolescents.

Intracranial hypotension masquerading as nonconvulsive status epilepticus: report of 3 cases.

Intracranial hypotension (IH) has been a known entity in neurocritical care since 1938. Even though many cases are spontaneous, the incidence of intracranial hypotension in the neurocritical care setting is increasing by virtue of the increased number of neurosurgical interventions. Whether spontaneous or secondary in etiology, diagnosis of IH usually requires the presence of orthostatic symptoms, including headaches and nausea with low opening CSF pressure. However, typical clinical features in the appropriate clinical context and imaging, even with normal CSF pressure, can indicate IH. In the neurocritical care setting, challenges for accurate semiology include altered sensorium and reduced levels of responsiveness for which many etiologies may exist, including metabolic dysfunction, traumatic brain injury, IH, or nonconvulsive status epilepticus (NCSE). The authors describe 3 patients whose clinical picture and electroencephalography (EEG) findings initially suggested NCSE but who did not respond to treatment with antiepileptic drugs alone. Neuroimaging suggested IH, and subsequent treatment of IH successfully improved the patient's clinical status. To the authors' knowledge this paper is the first in the literature that reports a correlation of IH with electrographic findings similar to NCSE as cause and effect. The authors' hypothesis is that thalamocortical dysfunction causes EEG findings that appear to be similar to those in NCSE but that these conditions do not coexist. The EEG activity is not epileptogenic, and IH results in blocking network pathways producing thalamocortical dysfunction. The authors discuss the hypothesis and pathophysiology of these epileptiform changes in relation to IH.

Ipsilateral synkinesia involves the supplementary motor area.

The supplementary motor area coordinates movements. Synkinesia is a rare disorder in which an involuntary movement occurs coordinated with a voluntary movement. Here, we test the hypothesis that the supplementary motor area is involved in involuntary coordination of movement. We collected functional magnetic resonance imaging (fMRI) data from two patients with ipsilateral hand-foot synkinesia and two control participants while they performed rhythmic tasks. In synkinesia patients, both the supplementary motor area and the foot motor cortex were significantly activated during the hand motor task. This pattern was not seen in controls. Our findings suggest that the supplementary motor area plays a central role in involuntary coordination observed in synkinesia, and provides insight into how the supplementary motor area orchestrates movements.

Posterior reversible encephalopathy syndrome (PRES) and CT perfusion changes.

Posterior reversible encephalopathy syndrome (PRES) can present with focal neurologic deficits, mimicking a stroke and can often represent a diagnostic challenge when presenting atypically. A high degree of suspicion is required in the clinical setting in order to yield the diagnosis. Cerebral CT perfusion (CTP) is utilized in many institutions as the first line in acute stroke imaging. CTP has proved to be a very sensitive measure of cerebral blood flow dynamics, most commonly employed to delineate the infarcted tissue from penumbra (at-risk tissue) in ischemic strokes. But abnormal CTP is also seen in stroke mimics such as seizures, hypoglycemia, tumors, migraines and PRES. In this article we describe a case of PRES in an elderly bone marrow transplant recipient who presented with focal neurological deficits concerning for a cerebrovascular accident. CTP played a pivotal role in the diagnosis and initiation of appropriate management. We also briefly discuss the pathophysiology of PRES.