Use of Epivolve phage display to generate a monoclonal antibody with opsonic activity directed against a subdominant epitope on extracellular loop 4 of Treponema pallidum BamA (TP0326).

Introduction: Syphilis, a sexually transmitted infection caused by the spirochete Treponema pallidum (Tp), is resurging globally. Tp's repertoire of outer membrane proteins (OMPs) includes BamA (ß-barrel assembly machinery subunit A/TP0326), a bipartite protein consisting of a 16-stranded ß-barrel with nine extracellular loops (ECLs) and five periplasmic POTRA (polypeptide transport-associated) domains. BamA ECL4 antisera promotes internalization of Tp by rabbit peritoneal macrophages. Methods: Three overlapping BamA ECL4 peptides and a two-stage, phage display strategy, termed "Epivolve" (for epitope evolution) were employed to generate single-chain variable fragments (scFvs). Additionally, antisera generated by immunizing mice and rabbits with BamA ECL4 displayed by a Pyrococcus furiosus thioredoxin scaffold (PfTrxBamA/ECL4). MAbs and antisera reactivities were evaluated by immunoblotting and ELISA. A comparison of murine and rabbit opsonophagocytosis assays was conducted to evaluate the functional ability of the Abs (e.g., opsonization) and validate the mouse assay. Sera from Tp-infected mice (MSS) and rabbits (IRS) were evaluated for ECL4-specific Abs using PfTrxBamA/ECL4 and overlapping ECL4 peptides in immunoblotting and ELISA assays. Results: Each of the five mAbs demonstrated reactivity by immunoblotting and ELISA to nanogram amounts of PfTrxBamA/ECL4. One mAb, containing a unique amino acid sequence in both the light and heavy chains, showed activity in the murine opsonophagocytosis assay. Mice and rabbits hyperimmunized with PfTrxBamA/ECL4 produced opsonic antisera that strongly recognized the ECL presented in a heterologous scaffold and overlapping ECL4 peptides, including S2. In contrast, Abs generated during Tp infection of mice and rabbits poorly recognized the peptides, indicating that S2 contains a subdominant epitope. Discussion: Epivolve produced mAbs target subdominant opsonic epitopes in BamA ECL4, a top syphilis vaccine candidate. The murine opsonophagocytosis assay can serve as an alternative model to investigate the opsonic potential of vaccinogens. Detailed characterization of BamA ECL4-specific Abs provided a means to dissect Ab responses elicited by Tp infection.

Derivation of splice junction-specific antibodies using a unique hapten targeting strategy and directed evolution.

Alternative splicing of RNA occurs frequently in eukaryotic cells and can result in multiple protein isoforms that are nearly identical in amino acid sequence, but have unique biological roles. Moreover, the relative abundance of these unique isoforms can be correlative with diseased states and potentially used as biomarkers or therapeutic targets. However, due to high sequence similarities among isoforms, current proteomic methods are incapable of differentiating native protein isoforms derived from most alternative splicing events. Herein, a strategy employing a nonsynonymous, non-native amino acid (nnAA) pseudo-hapten (i.e. an amino acid or amino acid derivative that is different from the native amino acid at a particular position) as a targeting epitope in splice junction-spanning peptides was successful in directed antibody derivation. After isolating nnAA-specific antibodies, directed evolution reduced the antibody's binding dependence on the nnAA pseudo-hapten and improved binding to the native splice junction epitope. The resulting antibodies demonstrated codependent binding affinity to each exon of the splice junction and thus are splice junction- and isoform-specific. Furthermore, epitope scanning demonstrated that positioning of the nnAA pseudo-hapten within a peptide antigen can be exploited to predetermine the isolated antibody's specificity at, or near, amino acid resolution. Thus, this nnAA targeting strategy has the potential to robustly derive splice junction- and site-specific antibodies that can be used in a wide variety of research endeavors to unambiguously differentiate native protein isoforms.

Autosomal dominant and sporadic late onset Alzheimer's disease share a common in vivo pathophysiology.

The extent to which the pathophysiology of autosomal dominant Alzheimer's disease corresponds to the pathophysiology of 'sporadic' late onset Alzheimer's disease is unknown, thus limiting the extrapolation of study findings and clinical trial results in autosomal dominant Alzheimer's disease to late onset Alzheimer's disease. We compared brain MRI and amyloid PET data, as well as CSF concentrations of amyloid-ß42, amyloid-ß40, tau and tau phosphorylated at position 181, in 292 carriers of pathogenic variants for Alzheimer's disease from the Dominantly Inherited Alzheimer Network, with corresponding data from 559 participants from the Alzheimer's Disease Neuroimaging Initiative. Imaging data and CSF samples were reprocessed as appropriate to guarantee uniform pipelines and assays. Data analyses yielded rates of change before and after symptomatic onset of Alzheimer's disease, allowing the alignment of the ∼30-year age difference between the cohorts on a clinically meaningful anchor point, namely the participant age at symptomatic onset. Biomarker profiles were similar for both autosomal dominant Alzheimer's disease and late onset Alzheimer's disease. Both groups demonstrated accelerated rates of decline in cognitive performance and in regional brain volume loss after symptomatic onset. Although amyloid burden accumulation as determined by PET was greater after symptomatic onset in autosomal dominant Alzheimer's disease than in late onset Alzheimer's disease participants, CSF assays of amyloid-ß42, amyloid-ß40, tau and p-tau181 were largely overlapping in both groups. Rates of change in cognitive performance and hippocampal volume loss after symptomatic onset were more aggressive for autosomal dominant Alzheimer's disease participants. These findings suggest a similar pathophysiology of autosomal dominant Alzheimer's disease and late onset Alzheimer's disease, supporting a shared pathobiological construct.

Region-based analysis of rare genomic variants in whole-genome sequencing datasets reveal two novel Alzheimer's disease-associated genes: DTNB and DLG2.

Alzheimer's disease (AD) is a genetically complex disease for which nearly 40 loci have now been identified via genome-wide association studies (GWAS). We attempted to identify groups of rare variants (alternate allele frequency <0.01) associated with AD in a region-based, whole-genome sequencing (WGS) association study (rvGWAS) of two independent AD family datasets (NIMH/NIA; 2247 individuals; 605 families). Employing a sliding window approach across the genome, we identified several regions that achieved association p values <10-6, using the burden test or the SKAT statistic. The genomic region around the dystobrevin beta (DTNB) gene was identified with the burden and SKAT test and replicated in case/control samples from the ADSP study reaching genome-wide significance after meta-analysis (pmeta = 4.74 × 10-8). SKAT analysis also revealed region-based association around the Discs large homolog 2 (DLG2) gene and replicated in case/control samples from the ADSP study (pmeta = 1 × 10-6). In conclusion, in a region-based rvGWAS of AD we identified two novel AD genes, DLG2 and DTNB, based on association with rare variants.

Ranking Important Factors for Using Postoperative Chemotherapy in Nonmuscle Invasive Bladder Cancer: Conjoint Analysis Results From the Michigan Urological Surgery Improvement Collaborative (MUSIC).

PURPOSE: National and international guidelines recommend the use of 1 dose of intravesical chemotherapy immediately following surgery for nonmuscle invasive bladder cancer, which is performed infrequently on a population level. We sought to understand the importance of potential environmental and clinical dimensions involved in the decision to offer this therapy. MATERIALS AND METHODS: Urologists from the Michigan Urological Surgery Improvement Collaborative (MUSIC) rated 8 distinct clinical vignettes involving patients with nonmuscle invasive bladder cancer. A ratings-based conjoint analysis method was used to evaluate the clinical vignette responses. Each vignette included 4 clinical dimensions and 2 environmental dimensions, with each dimension consisting of 2 possible attributes. The relative importance of each attribute was derived from the regression model and ranked in order. RESULTS: A total of 58 urologists answered the clinical vignettes which represents >75% of MUSIC sites. The median age of urologists was 53, most were male, and median years in practice was 20 years post residency. An environmental attribute, having a recovery room protocol for instilling and disposing of the chemotherapy, ranked as the most influential attribute for giving postoperative chemotherapy (utility=8.6). The clinical attribute yielding the strongest preference for giving chemotherapy was tumor grade (utility=4.9). These preferences varied by different subgroups of urologists, particularly regarding the type of practice a urologist was in. CONCLUSIONS: This study demonstrates that urologists have clear preferences for when they offer postoperative immediate chemotherapy. Factors beyond just clinical variables play a role in this decision making process such as the structure of the recovery room.

Validation of Plasma Amyloid-ß 42/40 for Detecting Alzheimer Disease Amyloid Plaques.

BACKGROUND AND OBJECTIVES: To determine the diagnostic accuracy of a plasma Aß42/Aß40 assay in classifying amyloid PET status across global research studies using samples collected by multiple centers that utilize different blood collection and processing protocols. METHODS: Plasma samples (n = 465) were obtained from 3 large Alzheimer disease (AD) research cohorts in the United States (n = 182), Australia (n = 183), and Sweden (n = 100). Plasma Aß42/Aß40 was measured by a high precision immunoprecipitation mass spectrometry (IPMS) assay and compared to the reference standards of amyloid PET and CSF Aß42/Aß40. RESULTS: In the combined cohort of 465 participants, plasma Aß42/Aß40 had good concordance with amyloid PET status (receiver operating characteristic area under the curve [AUC] 0.84, 95% confidence interval [CI] 0.80-0.87); concordance improved with the inclusion of APOE ε4 carrier status (AUC 0.88, 95% CI 0.85-0.91). The AUC of plasma Aß42/Aß40 with CSF amyloid status was 0.85 (95% CI 0.78-0.91) and improved to 0.93 (95% CI 0.89-0.97) with APOE ε4 status. These findings were consistent across the 3 cohorts, despite differences in protocols. The assay performed similarly in both cognitively unimpaired and impaired individuals. DISCUSSION: Plasma Aß42/Aß40 is a robust measure for detecting amyloid plaques and can be utilized to aid in the diagnosis of AD, identify those at risk for future dementia due to AD, and improve the diversity of populations enrolled in AD research and clinical trials. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that plasma Aß42/Aß40, as measured by a high precision IPMS assay, accurately diagnoses brain amyloidosis in both cognitively unimpaired and impaired research participants.

Barriers to single-dose intravesical chemotherapy in non-muscle invasive bladder cancer: what's the problem?

INTRODUCTION: The intravesical instillation of mitomycin C immediately following surgery for non-muscle invasive bladder cancer has been shown to be efficacious in reducing cancer recurrence. As a result, the American Urological Association adopted guidelines for non-muscle invasive bladder cancer care to support its use in low to intermediate risk patients. Despite this, urologists' use of this drug following transurethral resection of a bladder tumor (TURBT) has been reported as low as 5% or less. Our study objective was to better understand the barriers urologists experience in using mitomycin C. METHODS: Semi-structured interviews were conducted with 13 practicing urologists at 4 geographically distinct practice locations throughout Indiana between 2017 and 2018. Cognitive task analysis was used to explore factors that influenced their clinician decision-making about Mitomycin C use following TURBT in specific patient cases. Interview transcripts were coded and analyzed using immersion/crystallization to identify emergent themes. RESULTS: The median age of the urologists interviewed was 44 (IQR 40-48). Eighty-five percent were male. Approximately 30% had completed urologic fellowship training; 62% were in private practice. Three major themes related to the use of mitomycin C emerged: cumbersome workflow processes, urologists' fears of side effects, and issues of identifying patients most likely to benefit. CONCLUSION: Workflow, fear, and value are key factors and also represent complexities of translating efficacy into effectiveness for a drug with known benefits to patients. Areas of potential intervention development to improve the use of mitomycin C to reduce recurrence of bladder cancer are suggested. Alternatives such as gemcitabine may also help overcome these barriers.

Dutch Brain Research Registry for study participant recruitment: Design and first results.

INTRODUCTION: The Dutch Brain Research Registry aims to facilitate online recruitment of participants for brain disease studies. METHODS: Registrants were primarily recruited through an online social media campaign. The registration process included a short questionnaire, which was subsequently used in the prescreening process to match participants to studies. RESULTS: In the first 18 months, 17,218 registrants signed up (58±11 years old, 78% female). Out of 34,696 study invitations that were sent, 36% were accepted by registrants, of which 50% to 84% were finally enrolled, resulting in 10,661 participants in 28 studies. Compared to non-participants, study participants were more often older, male, more highly educated, retired or unemployed, non-smoking, healthier, and more often had a family member with dementia. DISCUSSION: The Dutch Brain Research Registry facilitates effective matching of participants to brain disease studies. Participant factors related to study enrollment may reflect facilitators or barriers for participation, which is useful for improving recruitment strategies.

Increasing the cervical and lumbar lordosis is possible despite overt osteoarthritis and spinal stenosis using extension traction to relieve low back and leg pain in a 66-year-old surgical candidate: a CBP® case report.

[Purpose] To present the case of the dramatic relief of low back pain, leg pain and disability in an older female with osteoarthritis, lumbar spinal stenosis and hypolordosis of the cervical and lumbar spine. [Participant and Methods] A 66-year-old female presented with chronic low back pain, right leg pain, numbness and weakness. Despite being recommended for surgery, the patient sought alternative treatment. The patient was treated with Chiropractic BioPhysics® rehabilitation of the spine with the objective to increase the lumbar and cervical lordoses. Cervical and lumbar extension exercises and traction were performed as well as spinal manipulation. Treatment was performed approximately three times per week for 6.5 months. [Results] Re-assessment after treatment demonstrated significant reduction of low back pain, leg pain and other health improvements. X-rays showed structural improvements in the cervical and lumbar spine despite advanced osteoarthritis. [Conclusion] Lumbar and cervical hypolordosis subluxation may be increased in those with spinal deformity caused symptoms, despite the presence of osteoarthritis and degenerative stenosis of the spine. Spinal x-rays as used in the assessment and monitoring of patients being treated with contemporary spinal rehabilitation methods are not harmful and should be used for routine screening purposes.

Preadmission antidepressant use and bladder cancer: a population-based cohort study of stage at diagnosis, time to surgery, and surgical outcomes.

BACKGROUND: Among cancer patients, prior antidepressant use has been associated with impaired survival. This could be due to differences in stage at diagnosis, in receipt of treatment, or in treatment complications. The purpose of this study was, therefore, to examine if preadmission antidepressant use in patients with bladder cancer is associated with tumor stage at diagnosis, rate of cystectomy, and surgical outcomes, including survival. METHODS: We performed a registry-based cohort study including all patients with incident invasive bladder cancer in Denmark 2005-2015. Exposure was defined as redemption of two or more antidepressant prescriptions one year before cancer diagnosis. We compared tumor stage using logistic regression, postsurgical inpatient length of stay using linear regression, and other outcomes using Cox regression. All results were adjusted for age, sex, comorbidity, and marital status. RESULTS: Among 10,427 bladder cancer patients, 10% were antidepressant users. At diagnosis, 51% of users and 52% of non-users had muscle-invasive disease. However, upon adjustment for age, sex, comorbidity, and marital status, users had lower odds of muscle-invasive disease (adjusted odds ratio 0.86 (95% confidence interval (CI) 0.74-0.99)). Among patients with muscle-invasive disease, fewer users than non-users had surgery within three months (15% vs. 24%, adjusted hazard ratio (aHR) 0.75 (95% CI 0.59-0.95)). Of 2532 patients undergoing surgery, 6% were antidepressant users. Postsurgical inpatient length of stay did not differ between users and non-users. The 30-day cumulative incidence of readmission was higher for users (41% vs. 33%, aHR 1.33 (95% CI 1.05-1.67)), while the 90-day incidence of postoperative procedures was 44% for users and 38% for non-users (aHR 1.18 (95% CI 0.93-1.51)). One-year mortality was comparable in users (15%) and non-users (14%). CONCLUSIONS: Antidepressant use in bladder cancer patients was associated with less advanced stage at diagnosis and lower rate of cystectomy. After cystectomy, users had higher rate of readmission and postoperative procedures than non-users, but we found no difference in length of stay or one-year mortality. The results point to the importance of differentiated clinical care according to individual patient characteristics.

Targeted neurogenesis pathway-based gene analysis identifies ADORA2A associated with hippocampal volume in mild cognitive impairment and Alzheimer's disease.

Alzheimer's disease (AD) patients display hippocampal atrophy, memory impairment, and cognitive decline. New neurons are generated throughout adulthood in 2 regions of the brain implicated in AD, the dentate gyrus of the hippocampus and the subventricular zone of the olfactory bulb. Disruption of this process contributes to neurodegenerative diseases including AD, and many of the molecular players in AD are also modulators of adult neurogenesis. However, the genetic mechanisms underlying adult neurogenesis in AD have been underexplored. To address this gap, we performed a gene-based association analysis in cognitively normal and impaired participants using neurogenesis pathway-related candidate genes curated from existing databases, literature mining, and large-scale genome-wide association study findings. A gene-based association analysis identified adenosine A2a receptor (ADORA2A) as significantly associated with hippocampal volume and the association between rs9608282 within ADORA2A and hippocampal volume was replicated in the meta-analysis after multiple comparison adjustments (p = 7.88 × 10-6). The minor allele of rs9608282 in ADORA2A is associated with larger hippocampal volumes and better memory.

Long-term Health-related Quality of Life Outcomes Following Radical Cystectomy.

OBJECTIVE: To evaluate the long-term (>5 years) health-related quality of life (HRQOL) outcomes following radical cystectomy, comparing Indiana pouch (IP), neobladder (NB), and ileal conduit (IC). MATERIALS AND METHODS: The departmental radical cystectomy database was queried to identify patients who underwent radical cystectomy and urinary diversion for bladder cancer between 1991 and 2009 and had not died. Three hundred patients were identified and sent the validated Bladder Cancer Index instrument. RESULTS: A total of 128 (43%) patients completed the survey. When adjusted for gender, age at surgery, surgeon, and time since surgery, IC and IP patients had significantly better urinary function than NB patients (P = .0013). Sexual bother was less in NB than IP (P = .0387). Among men ≥65 years of age, IC patients had significantly better urinary function (P = .0376) than NB patients (91.6 vs 49.4, respectively). Among men <65 years of age, IC and IP patients (76.0 and 82.8, respectively) had significantly better urinary function than NB patients (50.7) (P = .0199). Among women greater than 65 years, bowel bother was significantly better (P = .0095) for IC patients than IP patients (44.8 vs 69.5, respectively). CONCLUSION: Urinary diversion type after radical cystectomy affects HRQOL differently in long-term survivors. Age and gender at surgery influenced HRQOL based on diversion procedure. Urinary function but not urinary bother was significantly better in IC and IP compared to NB diversions. Prospective longitudinal studies using validated HRQOL tools will further help guide preoperative diversion choice decisions between patient and surgeon.

Medication Use among Veterans across Health Care Systems.

INTRODUCTION: Dual healthcare system use can create gaps and fragments of information for patient care. The Department of Veteran Affairs is implementing a health information exchange (HIE) program called the Virtual Lifetime Electronic Record (VLER), which allows providers to access and share information across healthcare systems. HIE has the potential to improve the safety of medication use. However, data regarding the pattern of outpatient medication use across systems of care is largely unknown. Therefore, the objective of this study is to describe the prevalence of medication dispensing across VA and non-VA health care systems among a cohort Veteran population. METHODS: This study included all Veterans who had two outpatient visits or one inpatient visit at the Indianapolis VA during a 1-year period prior to VLER enrollment. Source of medication data was assessed at the subject level, and categorized as VA, INPC (non-VA), or both. The primary target was identification of sources for medication data. Then, we compared the mean number of prescriptions, as well as overall and pairwise differences in medication dispensing. RESULTS: Out of 52,444 Veterans, 17.4% of subjects had medication data available in a regional HIE. On average, 40 prescriptions per year were prescribed for Veterans who used both sources compared to 29 prescriptions per year from VA only and 25 prescriptions per year from INPC only sources. The annualized prescription rate of Veterans in the dual use group was 36% higher than those who had only VA data available and 61% higher than those who had only INPC data available. CONCLUSIONS: Our data demonstrated that 17.4% of subjects had medication use identified from non-VA sources, including prescriptions for antibiotics, antineoplastics, and anticoagulants. These data support the need for HIE programs to improve coordination of information, with the potential to reduce adverse medication interactions and improve medication safety.

Glutamine for the treatment of vincristine-induced neuropathy in children and adolescents with cancer.

BACKGROUND: Vincristine is an integral treatment component of many childhood tumors with potentially dose-limiting sensory and/or motor neuropathy. Results from a pilot study on the incidence of vincristine-induced peripheral neuropathy (VIPN) as well as the efficacy and safety of glutamine in reducing signs and symptoms of VIPN in children with cancer are presented. METHODS: Fifty-six patients between the ages of 5-21 with newly diagnosed leukemia, lymphoma, extracranial solid tumor or medulloblastoma and expected to receive a minimum cumulative dose of 6 mg/m2 of vincristine over a 30-week period were eligible. Patients' neurological functioning was monitored every 3 weeks using clinical history, exam, and assessment of motor functioning. Upon identification of neuropathy, patients were randomized to either glutamine (6 g/m2 per dose twice daily, maximum 10 g/dose) or placebo for a 3-week period followed by 3-week wash out period (Time 3). RESULTS: Forty-nine patients were fully evaluable and 100 % developed neuropathy per study definitions. No significant differences in demographics or side effects were noted between the randomized groups. The distribution of sensory neuropathy scores between the two groups was statistically significant after the intervention (p = 0.022). Children receiving glutamine also rated their quality of life (QoL) as 8.42 points higher on the PedsQL total score than those receiving placebo (p = 0.031). CONCLUSIONS: Glutamine supplementation is well tolerated and associated with improvements in sensory function and self-reported overall quality of life. Future studies are warranted to confirm the efficacy of glutamine for the treatment of vincristine-related sensory neuropathy in pediatric cancer patients.

Active Cigarette Smoking in Cognitively-Normal Elders and Probable Alzheimer's Disease is Associated with Elevated Cerebrospinal Fluid Oxidative Stress Biomarkers.

Neurodegenerative diseases and chronic cigarette smoking are associated with increased cerebral oxidative stress (OxS). Elevated F2-isoprostane levels in biological fluid is a recognized marker of OxS. This study assessed the association of active cigarette smoking with F2-isoprostane in concentrations in cognitively-normal elders (CN), and those with mild cognitive impairment (MCI) and probable Alzheimer's disease (AD). Smoking and non-smoking CN (n = 83), MCI (n = 164), and probable AD (n = 101) were compared on cerebrospinal fluid (CSF) iPF2α-III and 8,12, iso-iPF2α-VI F2-isoprostane concentrations. Associations between F2-isoprostane levels and hippocampal volumes were also evaluated. In CN and AD, smokers had higher iPF2α-III concentration; overall, smoking AD showed the highest iPF2α-III concentration across groups. Smoking and non-smoking MCI did not differ on iPF2α-III concentration. No group differences were apparent on 8,12, iso-iPF2α-VI concentration, but across AD, higher 8,12, iso-iPF2α-VI level was related to smaller left and total hippocampal volumes. Results indicate that active cigarette smoking in CN and probable AD is associated with increased central nervous system OxS. Further investigation of factors mediating/moderating the absence of smoking effects on CSF F2-isoprostane levels in MCI is warranted. In AD, increasing magnitude of OxS appeared to be related to smaller hippocampal volume. This study contributes additional novel information to the mounting body of evidence that cigarette smoking is associated with adverse effects on the human central nervous system across the lifespan.

Interaction of Cigarette Smoking History With APOE Genotype and Age on Amyloid Level, Glucose Metabolism, and Neurocognition in Cognitively Normal Elders.

INTRODUCTION: Chronic cigarette smoking is associated with increased risk for Alzheimer's disease (AD). The goal of this study was to determine if smoking history moderated the associations of age and APOE genotype (the most robust risk factors for AD) on brain amyloid deposition, glucose metabolism, and neurocognition in cognitively-normal elders. METHODS: Participants (n = 264) were grouped according to their APOE ε4 carrier status (ε4 carrier: APOE4+; non-ε4 carrier: APOE4-) and smoking status (smokers: at least 1 year of smoking during lifetime; never-smokers: no history of smoking). Approximately 89% of the smoking sample was former-smokers. We specifically tested for interactions of smoking status with APOE ε4 carrier status and age on measures of cortical amyloid deposition, glucose metabolism, and neurocognition. RESULTS: (1) smoking status interacted with APOE ε4 carrier status, where smoker APOE4+ showed lower glucose metabolism and poorer auditory-verbal learning and memory than never-smoking APOE4-, never-smoking APOE4+, and smoking APOE4-; (2) smoking status interacted with age on measures of semantic fluency, processing speed/set-shifting and global neurocognition; smokers, irrespective of APOE ε4 carrier status, demonstrated poorer performance with increasing age than never-smokers; and (3) smoking APOE4+ and never-smoking APOE4+ showed greater cortical amyloid deposition than never-smoking APOE4- and smoking APOE4-. CONCLUSIONS: The findings indicate consideration of smoking history is essential to both better understand the factors associated with neurobiological and neurocognitive abnormalities in elders, and the risk for development of AD-related neuropathology.

Brain amyloidosis ascertainment from cognitive, imaging, and peripheral blood protein measures.

BACKGROUND: The goal of this study was to identify a clinical biomarker signature of brain amyloidosis in the Alzheimer's Disease Neuroimaging Initiative 1 (ADNI1) mild cognitive impairment (MCI) cohort. METHODS: We developed a multimodal biomarker classifier for predicting brain amyloidosis using cognitive, imaging, and peripheral blood protein ADNI1 MCI data. We used CSF ß-amyloid 1-42 (Aß42) ≤ 192 pg/mL as proxy measure for Pittsburgh compound B (PiB)-PET standard uptake value ratio ≥ 1.5. We trained our classifier in the subcohort with CSF Aß42 but no PiB-PET data and tested its performance in the subcohort with PiB-PET but no CSF Aß42 data. We also examined the utility of our biomarker signature for predicting disease progression from MCI to Alzheimer dementia. RESULTS: The CSF training classifier selected Mini-Mental State Examination, Trails B, Auditory Verbal Learning Test delayed recall, education, APOE genotype, interleukin 6 receptor, clusterin, and ApoE protein, and achieved leave-one-out accuracy of 85% (area under the curve [AUC] = 0.8). The PiB testing classifier achieved an AUC of 0.72, and when classifier self-tuning was allowed, AUC = 0.74. The 36-month disease-progression classifier achieved AUC = 0.75 and accuracy = 71%. CONCLUSIONS: Automated classifiers based on cognitive and peripheral blood protein variables can identify the presence of brain amyloidosis with a modest level of accuracy. Such methods could have implications for clinical trial design and enrollment in the near future. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that a classification algorithm based on cognitive, imaging, and peripheral blood protein measures identifies patients with brain amyloid on PiB-PET with moderate accuracy (sensitivity 68%, specificity 78%).

Alzheimer risk genes modulate the relationship between plasma apoE and cortical PiB binding.

OBJECTIVE: We investigated the association between apoE protein plasma levels and brain amyloidosis and the effect of the top 10 Alzheimer disease (AD) risk genes on this association. METHODS: Our dataset consisted of 18 AD, 52 mild cognitive impairment, and 3 cognitively normal Alzheimer's Disease Neuroimaging Initiative 1 (ADNI1) participants with available [(11)C]-Pittsburgh compound B (PiB) and peripheral blood protein data. We used cortical pattern matching to study associations between plasma apoE and cortical PiB binding and the effect of carrier status for the top 10 AD risk genes. RESULTS: Low plasma apoE was significantly associated with high PiB SUVR, except in the sensorimotor and entorhinal cortex. For BIN1 rs744373, the association was observed only in minor allele carriers. For CD2AP rs9349407 and CR1 rs3818361, the association was preserved only in minor allele noncarriers. We did not find evidence for modulation by CLU, PICALM, ABCA7, BIN1, and MS4A6A. CONCLUSIONS: Our data show that BIN1 rs744373, CD2AP rs9349407, and CR1 rs3818361 genotypes modulate the association between apoE protein plasma levels and brain amyloidosis, implying a potential epigenetic/downstream interaction.

History of cigarette smoking in cognitively-normal elders is associated with elevated cerebrospinal fluid biomarkers of oxidative stress.

BACKGROUND: Cigarette smoking in adults is associated with abnormalities in brain neurobiology. Smoking-induced central nervous system oxidative stress (OxS) is a potential mechanism associated with these abnormalities. The goal of this study was to compare cognitively-normal elders on cerebrospinal fluid (CSF) levels of F2-isoprostane biomarkers of OxS. METHODS: Elders with a lifetime history of smoking (smokers; n=50; 75±5 years of age; 34±28 pack-years; approximately 12% were actively smoking at the time of study) were compared to never-smokers (n=61; 76±6 years of age) on CSF iPF2α-III and 8,12, iso-iPF2α-VI F2-isoprostanes levels. F2-isoprostanes levels were quantitated with HPLC-atmospheric pressure chemical ionization-tandem mass spectrometry. Associations between F2-isoprostanes levels, hippocampal volumes, and cigarette exposure measures were also evaluated. RESULTS: Smokers showed higher iPF2α-III level than never-smokers. An age×smoking status interaction was observed for 8,12, iso-iPF2α-VI, where smokers demonstrate a significantly greater concentration with increasing age than never-smokers. In smokers only, higher 8,12, iso-iPF2α-VI concentration was associated with smaller hippocampal volume, and greater iPF2α-III level was related to greater pack years. CONCLUSIONS: This is the first study to demonstrate that a history of cigarette smoking in cognitively-normal elders was associated with significantly elevated CSF F2-isoprostane levels and greater age-related increases in F2-isoprostanes, and that higher F2-isoprostane levels in smokers were related to smaller hippocampal volume. These findings provide additional novel evidence that a history of chronic smoking during adulthood is associated with adverse effects on the human brain that are potentially enduring even with extended smoking cessation.

APOE-epsilon4 and aging of medial temporal lobe gray matter in healthy adults older than 50 years.

Atrophy of the hippocampus and surrounding temporal regions occurs in Alzheimer's disease (AD). APOE ε4, the major genetic risk factor for late-onset AD, has been associated with smaller volume in these regions before amyloidosis can be detected by AD biomarkers. To examine APOE ε4 effects in relation to aging, we performed a longitudinal magnetic resonance imaging study involving cognitively normal adults (25 APOE ε4 carriers and 31 ε3 homozygotes), initially aged 51-75 years. We used growth curve analyses, which can provide information about APOE ε4-related differences initially and later in life. Hippocampal volume was the primary outcome; nearby medial temporal regions were secondary outcomes. Brain-derived neurotrophic factor, val66met was a secondary covariate. APOE ε4 carriers had significantly smaller initial hippocampal volumes than ε3 homozygotes. Rate of hippocampal atrophy was not greater in the APOE ε4 group, although age-related atrophy was detected in the overall sample. The findings add to the growing evidence that effects of APOE ε4 on hippocampal size begin early in life, underscoring the importance of early interventions to increase reserve.