Biomarkers of Alzheimer's Disease Among Mexican Americans

Article type: Research Article

Authors: O'Bryant, Sid E.^{a; b; *} | Xiao, Guanghua^c | Edwards, Melissa^{a; d} | Devous, Michael^e | Gupta, Veer Bala^{f; g} | Martins, Ralph^{f; g} | Zhang, Fan^h | Barber, Robert^{b; i} | for the Texas Alzheimer's Research and Care Consortium (TARCC)¹

Affiliations: [a] Department of Internal Medicine, University of North Texas Health Sciences Center, Fort Worth, TX, USA | [b] Institute for Aging & Alzheimer's Disease Research, University of North Texas Health Sciences Center, Fort Worth, TX, USA | [c] Department of Clinical Sciences, University of Texas Southwestern Medical Center, Psychiatry, and Neurology, Dallas, TX, USA | [d] Department of Clinical Health Psychology, University of North Texas, Denton, TX, USA | [e] Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA | [f] Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, WA, Australia | [g] Sir James McCusker Alzheimer's Disease Research Unit (Hollywood Private Hospital), Perth, WA, Australia | [h] Department of Academic and Institutional Resources and Technology, University of North Texas Health Sciences Center, Fort Worth, TX, USA | [i] Department of Pharmacology, University of North Texas Health Science Center, Fort Worth, TX, USA

Correspondence: [*] Correspondence to: Sid E. O'Bryant, Ph.D., University of North Texas Health Science Center, Department of Internal Medicine, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA. Tel.: +1817 735 2961; Fax: +1817 735 0611; E-mail: Sid.O'Bryant@unthsc.edu.

Note: [1] Investigators from the Texas Alzheimer’s Research and Care Consortium: Baylor College of Medicine: Rachelle Doody MD, PhD, Susan Rountree MD, Valory Pavlik PhD,Wen Chan PhD, Paul Massman PhD, Eveleen Darby, Tracy Evans RN, Aisha Khaleeq; Texas Tech University Health Science Center: Gregory Schrimsher, PhD, AndrewDentino, MD, Ronnie Orozco,Vicki Ramirez; University of North Texas Health Science Center: Thomas Fairchild, PhD, Janice Knebl, DO, James Hall, PhD, Douglas Mains, PhD, Leigh Johnson, PhD, Lisa Alvarez, Erin Braddock, Rosemary McCallum; University of Texas Southwestern Medical Center: Perrie Adams, PhD, Roger Rosenberg, MD, Myron Weiner, MD, Mary Quiceno, MD, Joan Reisch, PhD, Benjamin Williams, MD, PhD, Ryan Huebinger, PhD, Doris Svetlik, Amy Werry, Janet Smith; University of Texas Health Science Center – San Antonio: Donald Royall, MD, Raymond Palmer, PhD, Marsha Polk.

Abstract: Background:Mexican Americans are the fastest aging segment of the U.S. population, yet little scientific literature exists regarding the Alzheimer’s disease (AD) among this segment of the population. The extant literature suggests that biomarkers of AD will vary according to race/ethnicity though no prior work has explicitly studied this possibility. The aim of this study was to create a serum-based biomarker profile of AD among Mexican American. Methods:Data were analyzed from 363 Mexican American participants (49 AD and 314 normal controls) enrolled in the Texas Alzheimer’s Research & Care Consortium (TARCC). Non-fasting serum samples were analyzed using a luminex-based multi-plex platform. A biomarker profile was generated using random forest analyses. Results:The biomarker profile of AD among Mexican Americans was different from prior work from non-Hispanic populations with regards to the variable importance plots. In fact, many of the top markers were related to metabolic factors (e.g., FABP, GLP-1, CD40, pancreatic polypeptide, insulin-like-growth factor, and insulin). The biomarker profile was a significant classifier of AD status yielding an area under the receiver operating characteristic curve, sensitivity, and specificity of 0.77, 0.92, and 0.64, respectively. Combining biomarkers with clinical variables yielded a better balance of sensitivity and specificity. Conclusion:The biomarker profile for AD among Mexican American cases is significantly different from that previously identified among non-Hispanic cases from many large-scale studies. This is the first study to explicitly examine and provide support for blood-based biomarkers of AD among Mexican Americans. Areas for future research are highlighted.

Keywords: Alzheimer's disease, biomarkers, Mexican American, neuropsychology

DOI: 10.3233/JAD-122074

Journal: Journal of Alzheimer's Disease, vol. 34, no. 4, pp. 841-849, 2013