A blood biomarker test for brain amyloid impacts the clinical evaluation of cognitive impairment.

OBJECTIVE: The objective of this study was to examine clinicians' patient selection and result interpretation of a clinically validated mass spectrometry test measuring amyloid beta and ApoE blood biomarkers combined with patient age (PrecivityAD® blood test) in symptomatic patients evaluated for Alzheimer's disease (AD) or other causes of cognitive decline. METHODS: The Quality Improvement and Clinical Utility PrecivityAD Clinician Survey (QUIP I, ClinicalTrials.gov Identifier: NCT05477056) was a prospective, single-arm cohort study among 366 patients evaluated by neurologists and other cognitive specialists. Participants underwent blood biomarker testing and received an amyloid probability score (APS), indicating the likelihood of a positive result on an amyloid positron emission tomography (PET) scan. The primary study outcomes were appropriateness of patient selection as well as result interpretation associated with PrecivityAD blood testing. RESULTS: A 95% (347/366) concordance rate was noted between clinicians' patient selection and the test's intended use criteria. In the final analysis including these 347 patients (median age 75 years, 56% women), prespecified test result categories incorporated 133 (38%) low APS, 162 (47%) high APS, and 52 (15%) intermediate APS patients. Clinicians' pretest and posttest AD diagnosis probability changed from 58% to 23% in low APS patients and 71% to 89% in high APS patients (p < 0.0001). Anti-AD drug therapy decreased by 46% in low APS patients (p < 0.0001) and increased by 57% in high APS patients (p < 0.0001). INTERPRETATION: These findings demonstrate the clinical utility of the PrecivityAD blood test in clinical care and may have added relevance as new AD therapies are introduced.

Peripheral Markers of Vascular Endothelial Dysfunction Show Independent but Additive Relationships with Brain-Based Biomarkers in Association with Functional Impairment in Alzheimer's Disease.

BACKGROUND: Cerebrovascular dysfunction confers risk for functional decline in Alzheimer's disease (AD), yet the clinical interplay of these two pathogenic processes is not well understood. OBJECTIVE: We utilized Alzheimer's Disease Neuroimaging Initiative (ADNI) data to examine associations between peripherally derived soluble cell adhesion molecules (CAMs) and clinical diagnostic indicators of AD. METHODS: Using generalized linear regression models, we examined cross-sectional relationships of soluble plasma vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-Selectin to baseline diagnosis and functional impairment (clinical dementia rating sum-of-boxes, CDR-SB) in the ADNI cohort (n = 112 AD, n = 396 mild cognitive impairment (MCI), n = 58 cognitively normal). We further analyzed associations of these biomarkers with brain-based AD biomarkers in a subset with available cerebrospinal fluid (CSF) data (n = 351). p-values derived from main effects and interaction terms from the linear regressions were used to assess the relationship between independent and dependent variables for significance (significance level was set at 0.05 a priori for all analysis). RESULTS: Higher mean VCAM-1 (p = 0.0026) and ICAM-1 (p = 0.0189) levels were found in AD versus MCI groups; however, not in MCI versus cognitively normal groups. Only VCAM-1 was linked with CDR-SB scores (p = 0.0157), and APOE ɛ4 genotype modified this effect. We observed independent, additive associations when VCAM-1 and CSF amyloid-ß (Aß42), total tau, phosphorylated tau (P-tau), or P-tau/Aß42 (all < p = 0.01) were combined in a CDR-SB model; ICAM-1 showed a similar pattern, but to a lesser extent. CONCLUSION: Our findings indicate independent associations of plasma-based vascular biomarkers and CSF biomarkers with AD-related clinical impairment.

Pilot study of an Alzheimer's disease risk assessment program in a primary care setting.

INTRODUCTION: The goal of this study was to pilot a referral-based cognitive screening and genetic testing program for Alzheimer's disease (AD) risk assessment in a primary care setting. METHODS: Primary care providers (PCPs; N = 6) referred patients (N = 94; M = 63 years) to the Rhode Island Alzheimer's Disease Prevention Registry for apolipoprotein E (APOE) genotyping and cognitive screening. PCPs disclosed test results to patients and counseled them about risk factor modification. RESULTS: Compared to the Registry as a whole, participants were younger, more likely to be non-White, and had lower cognitive screening scores. Mild cognitive impairment participants correctly reported a higher perceived risk of developing AD. Patients who recalled being counseled about modifiable risk factors were more likely to report positive health behavior changes. DISCUSSION: A referral-based program for cognitive and genetic AD risk assessment in a primary care setting is feasible, acceptable to patients, and yielded a more demographically diverse sample than an AD prevention registry.

Novel blood test for early biomarkers of preeclampsia and Alzheimer's disease.

A non-invasive and sensitive blood test has long been a goal for early stage disease diagnosis and treatment for Alzheimer's disease (AD) and other proteinopathy diseases. We previously reported that preeclampsia (PE), a severe pregnancy complication, is another proteinopathy disorder with impaired autophagy. We hypothesized that induced autophagy deficiency would promote accumulation of pathologic protein aggregates. Here, we describe a novel, sensitive assay that detects serum protein aggregates from patients with PE (n = 33 early onset and 33 late onset) and gestational age-matched controls (n = 77) as well as AD in both dementia and prodromal mild cognitive impairment (MCI, n = 24) stages with age-matched controls (n = 19). The assay employs exposure of genetically engineered, autophagy-deficient human trophoblasts (ADTs) to serum from patients. The aggregated protein complexes and their individual components, including transthyretin, amyloid ß-42, α-synuclein, and phosphorylated tau231, can be detected and quantified by co-staining with ProteoStat, a rotor dye with affinity to aggregated proteins, and respective antibodies. Detection of protein aggregates in ADTs was not dependent on transcriptional upregulation of these biomarkers. The ROC curve analysis validated the robustness of the assay for its specificity and sensitivity (PE; AUC: 1, CI: 0.949-1.00; AD; AUC: 0.986, CI: 0.832-1.00). In conclusion, we have developed a novel, noninvasive diagnostic and predictive assay for AD, MCI and PE.

Prior treatment (priming) with caffeine sensitizes D2-dopamine-mediated contralateral rotational behavior in 6-hydroxydopamine-lesioned rats.

BACKGROUND/AIMS: In unilaterally dopamine-depleted rats, repeated treatment with dopamine agonists sensitizes contralateral rotational behavior. Since A2a adenosine receptors are co-localized with D2 dopamine receptors in the brain, it was hypothesized that repeated treatment with the adenosine antagonist caffeine could sensitize D2 dopamine-mediated rotational behavior. METHODS: Rats were unilaterally lesioned with 6-hydroxydopamine (6-OHDA), and pretreated (primed) with 3 injections of caffeine or water. One week later, rats were challenged with the D2 agonist quinpirole (0.25 mg/kg). RESULTS: 6-OHDA rats primed with caffeine (50 mg/kg) displayed contralateral rotational behavior following challenge with quinpirole - an effect not observed with caffeine (10 or 75 mg/kg) or water. CONCLUSIONS: These results suggest that prior administration of caffeine can sensitize D2 dopamine-mediated rotational behavior in dopamine-depleted rats.

Susceptibility of human corneal endothelial cells to HSV-1 infection.

PURPOSE: The purpose of this study was to examine the intrinsic susceptibility of cultured human corneal endothelial cells (HCEC) to herpes simplex virus-1 (HSV-1) infection. We compared HSV-1 adsorption, kinetics of HSV-1 production, and pattern of viral plaque formation in cultured HCEC with those of a cell line used routinely for laboratory HSV propagation (African green monkey kidney fibroblast CV-1 cells). METHODS: Cultured HCEC and CV-1 cells were exposed to the McKrae strain of HSV-1 at 5 and 0.0001 multiplicities of infection (MOI). Using the 50% tissue culture infectious dose (TCID(50)) titration method, viral adsorption (at 5 MOI) and total virus production (at 5 and 0.0001 MOI) were compared to assess both susceptibility to viral attachment and productive viral infection, respectively. Additionally, visual observations were made at 0.0001 MOI using bright-field microscopy and immunofluorescence staining of viral antigens to compare patterns of viral spread in confluent monolayers of both cell types. RESULTS: The percentage of HSV-1 virion particles adsorbed by cultured HCEC and CV-1 cells was similar (35.9% and 33.0%, respectively, p = 0.07, NS), indicating similar susceptibility of the two cell types to initial HSV-1 attachment and adsorption. However, maximum total virus production was more than 3-fold higher for HCEC than for CV-1 cells (p < 0.005), suggesting higher susceptibility of HCEC cells to productive viral infection. Immunofluorescence studies of infected cell monolayers corroborated these quantitative findings, with HCEC monolayers demonstrating more rapid progression of cytopathic effect than CV-1 monolayers. CONCLUSIONS: In comparison to reference CV-1 cells, cultured HCEC show similar susceptibility to HSV-1 adsorption, but higher capacity to support productive HSV-1 infection. Our results suggest that human corneal endothelial cells may be inherently susceptible to HSV-1 infection.

Abnormal involuntary movement (AIM) expression following D2 dopamine agonist challenge is determined by the nature of prior dopamine receptor stimulation (priming) in 6-hydroxydopamine lesioned rats.

Rats with unilateral 6-hydroxydopamine (6-OHDA) lesions show sensitization (priming) of rotational behavior upon repeated treatment with dopamine agonists. To relate these observations to dyskinesias exhibited by Parkinson's Disease patients, we assessed abnormal involuntary movements (AIMs) in 6-OHDA rats, which were primed with three injections of either the following: water, D1/D2 agonist apomorphine (Apo) (0.5mg/kg), D1 agonist SKF38393 (SKF) (10mg/kg) or D2 agonist quinpirole (Quin) (1 or 2.5mg/kg). The rats were challenged one week later with Quin (0.25mg/kg). Axial, limb, orolingual, locomotor, and grooming AIMs were scored (0-4) every 5min. Priming with water did not produce AIMs. Priming with Quin (1mg/kg) produced axial and locomotor AIMs, while priming with Apo, SKF or Quin (2.5mg/kg) produced axial, locomotor, limb, and grooming AIMs. The disparity in AIM profiles between Quin (1mg/kg) and (2.5mg/kg) was not the result of D1 receptor stimulation since there was little striatal Fos expression following the third priming injection with Quin (1 or 2.5mg/kg) compared to following SKF, which led to robust striatal Fos expression. Challenge with Quin (0.25mg/kg) essentially reproduced the categories of AIMs exhibited during priming, with no AIMs in water-primed 6-OHDA rats, mild, non-significant, axial and locomotor AIMs in Quin (1 and 2.5mg/kg)-primed 6-OHDA rats, and axial, limb, locomotor, and grooming AIMs in Apo- and SKF-primed 6-OHDA rats. These data suggest that the types of AIMs expressed following challenge with Quin depend on the dopamine receptor subtype and dose of dopamine agonist used during priming.