Editorial: Human and Animal Models for Translational Research on Neurodegeneration: Challenges and Opportunities From South America

Abstract

Editorial on the Research Topic Human and animal models for translational research on neurodegeneration: challenges and opportunities from South America Facing the alarming growth of dementia and neurodegenerative conditions has become a critical priority across the globe (Alzheimer's Disease International, 2009; Lancet, 2015; Shah et al., 2016; Parra et al., 2018). Neurodegenerative diseases are the most frequent cause of dementia, representing a burden for public health systems (especially in middle and middle-high income countries). Although most research on this subject is concentrated in first-world centers, growing efforts in South American countries (SACs) are affording important breakthroughs. This emerging agenda poses not only new challenges for the region, but also new opportunities for the field at large. SACs have witnessed a promising development of relevant research in humans and animals, giving rise to new regional challenges. As highlighted in a recent experts' consensus paper Latin-American countries (LAC), and SACs in particular (Parra et al., 2018), face a critical situation. Higher demographic rates and the predicted prevalence of dementia have reached and even exceeded those of developing countries. In SACs, low- and middle-income countries (e.g., Bolivia, Paraguay), the prevalence of dementia will double that of high-income countries, while upper-middle-income countries in the region (e.g., Argentina, Brazil, Chile, Colombia, Peru, Uruguay, and Venezuela) will experience the greatest impact of dementia. The WHO estimated that the standardized prevalence of dementia in Latin America was 8.5%, but multiple SACs have been underrepresented or underestimated in such a calculation (Parra et al., 2018). Moreover, raw prevalence rates across studies are characterized by high variability within and between countries (e.g., Argentina: 8.3; Brazil: 7.1-2.0; Chile: 4.4-7.0; Colombia: 6.0; Peru: 6.72-9.3; Uruguay: 3.1; Venezuela: 5.7-13,7) (Parra et al., 2018). In addition, most of these studies are undermined by various limitations and methodological problems. Even considering these data, SACs possess the highest global prevalence of dementia after North Africa/Middle East in people above the age of 60 (Parra et al., 2018). Moreover, the harmonization of global strategies against dementia in these contexts is hindered not only by reduced epidemiological data, but also by the lack of standardized clinical practice, insufficient training of physicians, limited resources, and poor governmental support, let alone poverty and more general cultural barriers and stigmas. All of these factors have impacted the type and amount of research conducted in SACs. A regional network, based on multi-institutional actors from research, governmental, and private sectors is fundamental to overcome these challenges (Parra et al., 2018). Nevertheless, until now most research groups still work in isolation or in sporadic collaboration, without developing large-scale multicenter studies or active cooperation networks. The field could grow exponentially by combining the strengths of regional research with higher visibility, a translational philosophy, and enhanced global networking. Importantly, collaborative developments may promote the establishment of translational centers studying neurodegeneration. This Research Topic engages researchers from the world over, helping to integrate the international community of experts and to establish new challenges and developments for future investigation. We present original research in SACs, including studies assessing the interplay among genetic, neural, and behavioral dimensions of these diseases, as well as articles on vulnerability factors, comparisons of findings from various countries, and works promoting multicenter and collaborative networking. More generally, our Research Topic covers a broad scope of human research approaches (behavioral assessment, neuroimaging, electromagnetic techniques, brain connectivity, peripheral measures), animal methodologies (genetics, epigenetics, proteomics, metabolomics, other molecular biology tools), target species (human and non-human animals, sporadic, and genetic versions), and article types (mainly original research articles, but also case reports, data reports, commentaries, opinions, and reviews), all based on work conducted in SACs. Thus, in capturing the breakthroughs, possibilities, and limitations of such a promising niche, the present Research Topic (titled Human and animal models for translational research on neurodegeneration: challenges and opportunities from South America) represents a valuable forum to initialize a constructive dialogue and reflect on the present and future of neurodegenerative research in the region. Here, we summarize the main contributions included in the volume. Through this wide-ranging proposal, we hope to introduce a fresh approach to the challenges and opportunities of research on neurodegeneration across these countries, focusing on two overarching levels of evidence (human and animal research), as summarized below. Concerning human research, SACs offer invaluable possibilities to pursue neurogenetic studies and clinical trials. This region possesses the world's largest population of familial Alzheimer's and Huntington's disease (AD and HD, respectively), among others, alongside multiple novel and rare functional genomic variants of other disorders. Moreover, poor socioeconomic conditions in several communities provide a natural scenario to study the role of vulnerability, resilience, and genetic-cultural interaction on disease progression. These opportunities are already being exploited by consolidated research groups in Argentina, Chile, Colombia, Peru, and Brazil, among others, via cutting-edge approaches which include connectomics, omics-biomarkers, and neuropsychological assessment. Moreover, the emerging cognitive...