Browsing by Author "Darby, R. Ryan"

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    Comprehensive cross-sectional and longitudinal comparisons of plasma glial fibrillary acidic protein and neurofilament light across FTD spectrum disorders
    (Springer Nature, 2025-03-12) Sheth, Udit; Öijerstedt, Linn; Heckman, Michael G.; White, Launia J.; Heuer, Hilary W.; Lago, Argentina Lario; Forsberg, Leah K.; Faber, Kelley M.; Foroud, Tatiana M.; Rademakers, Rosa; Ramos, Eliana Marisa; Appleby, Brian S.; Bozoki, Andrea C.; Darby, R. Ryan; Dickerson, Bradford C.; Domoto-Reilly, Kimiko; Galasko, Douglas R.; Ghoshal, Nupur; Graff-Radford, Neill R.; Grant, Ian M.; Hales, Chadwick M.; Hsiung, Ging-Yuek Robin; Huey, Edward D.; Irwin, David; Kwan, Justin Y.; Litvan, Irene; Mackenzie, Ian R.; Masdeu, Joseph C.; Mendez, Mario F.; Onyike, Chiadi U.; Pascual, Belen; Pressman, Peter S.; Roberson, Erik D.; Snyder, Allison; Tartaglia, M. Carmela; Seeley, William W.; Dickson, Dennis W.; Rosen, Howard J.; Boeve, Bradley F.; Boxer, Adam L.; Petrucelli, Leonard; Gendron, Tania F.; Medical and Molecular Genetics, School of Medicine
    Background: Therapeutic development for frontotemporal dementia (FTD) is hindered by the lack of biomarkers that inform susceptibility/risk, prognosis, and the underlying causative pathology. Blood glial fibrillary acidic protein (GFAP) has garnered attention as a FTD biomarker. However, investigations of GFAP in FTD have been hampered by symptomatic and histopathologic heterogeneity and small cohort sizes contributing to inconsistent findings. Therefore, we evaluated plasma GFAP as a FTD biomarker and compared its performance to that of neurofilament light (NfL) protein, a leading FTD biomarker. Methods: We availed ARTFL LEFFTDS Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) study resources to conduct a comprehensive cross-sectional and longitudinal examination of the susceptibility/risk, prognostic, and predictive performance of GFAP and NfL in the largest series of well-characterized presymptomatic FTD mutation carriers and participants with sporadic or familial FTD syndromes. Utilizing single molecule array technology, we measured GFAP and NfL in plasma from 161 controls, 127 presymptomatic mutation carriers, 702 participants with a FTD syndrome, and 67 participants with mild behavioral and/or cognitive changes. We used multivariable linear regression and Cox proportional hazard models adjusted for co-variates to examine the biomarker utility of baseline GFAP and NfL concentrations or their rates of change. Results: Compared to controls, GFAP and NfL were elevated in each FTD syndrome but GFAP, unlike NfL, poorly discriminated controls from participants with mild symptoms. Similarly, both baseline GFAP and NfL were higher in presymptomatic mutation carriers who later phenoconverted, but NfL better distinguished non-converters from phenoconverters. We additionally observed that GFAP and NfL were associated with disease severity indicators and survival, but NfL far outperformed GFAP. Nevertheless, we validated findings that the GFAP/NfL ratio may discriminate frontotemporal lobar degeneration with tau versus TDP-43 pathology. Conclusions: Our head-to-head comparison of plasma GFAP and NfL as biomarkers for FTD indicate that NfL consistently outmatched GFAP as a prognostic and predictive biomarker for participants with a FTD syndrome, and as a susceptibility/risk biomarker for people at genetic risk of FTD. Our findings underscore the need to include leading biomarkers in investigations evaluating new biomarkers if the field is to fully ascertain their performance and clinical value.
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    Psychotropic medication usage in sporadic versus genetic behavioral-variant frontotemporal dementia
    (Wiley, 2025) Vargas-Gonzalez, Juan-Camilo; Dimal, Nico; Cortez, Kasey; Heuer, Hilary; Forsberg, Leah K.; Appleby, Brian S.; Barmada, Sami; Bozoki, Andrea; Clark, David; Cobigo, Yann; Darby, R. Ryan; Dickerson, Bradford C.; Domoto-Reilly, Kimiko; Galasko, Douglas R.; Geschwind, Daniel H.; Ghoshal, Nupur; Graff-Radford, Neill R.; Grant, Ian M.; Irwin, David; Hsiung, Ging-Yuek Robin; Honig, Lawrence S.; Kantarci, Kejal; Léger, Gabriel C.; Litvan, Irene; Mackenzie, Ian R.; Masdeu, Joseph C.; Mendez, Mario F.; Onyike, Chiadi U.; Pascual, Belen; Pressman, Peter; Ramos, Eliana Marisa; Roberson, Erik D.; Rogalski, Emily; Boeve, Brad F.; Boxer, Adam L.; Rosen, Howie J.; Tartaglia, Maria Carmela; ALLFTD Consortium Investigators; Neurology, School of Medicine
    Introduction: Psychotropic medication (PM) use in behavioral-variant frontotemporal dementia (bvFTD) is higher than in other dementias. However, no information exists on whether PM use differs between sporadic and genetic bvFTD. Methods: We analyzed data from sporadic and genetic bvFTD participants with PM prescriptions in the Advancing Research and Treatment in Frontotemporal Lobar Degeneration/Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects study. We estimated ordinal odds ratio (OOR) of having more PM comparing sporadic and genetic bvFTD. Finally, we explored the neuropsychiatric symptom (NPS) combinations using classification and regression trees (CART). Results: We included 263 with sporadic and 193 with genetic bvFTD. The OOR for sporadic bvFTD to be on PM was 1.75 (95% confidence interval: 1.21 to 2.53) for the fully adjusted model. CART revealed the most common NPS combination was apathy + personality changes in 18% of participants. Discussion: Participants with sporadic bvFTD were twice as likely to be on PM compared to genetic bvFTD. The reason for increased PM usage in sporadic bvFTD participants should be further investigated. Highlights: We report on patients with behavioral variant frontotemporal dementia (bvFTD). We evaluated the psychotropic medication (PM) prescription at baseline in the cohort. Patients with sporadic bvFTD had more prescriptions for PM than genetic patients. The frequency of symptoms combination was different in sporadic and genetic bvFTD.