Advances in Alzheimer’s disease (AAD): Standing firm at its first anniversary

Advances in Alzheimer’s Disease (AAD) is an international journal launched last year, dedicated to promote basic, translational and clinical research on Alzheimer’s Disease (AD) and brain aging (http://www.scirp.org/journal/aad/). On its first anniversary, the journal has made substantial achievements and shows a great promise for its future. AAD published the first issue on June 26 last year, followed by the second and third issues in September and December. The first issue of this year was published in March as scheduled. The current issue publishes 3 original and review articles. The published papers were contributed by investigators over the world, mostly outside China, covering broad and diverse topics on AD, from mechanistic study to disease diagnosis, care and treatment. These papers have attracted considerable attention in the field, with total views near 40 thousand and full article downloads over 6 thousand to date. AD is the most common type of dementia in the elderly. It attacks individuals aged over 65 in most cases, at a prevalence around 5%, which doubles every decade as the age goes further up. In 2013, an estimated 5 million Americans aged 65 and older have AD. The advances in modern medicine and the improvement in social and envi ronmental conditions will further increase human lifeexpectancy in the coming years, so do for the number of people who will develop this neurodegenerative disease. It is projected that 14 million Americans will live with AD by 2050 (http://www.alz.org/alzheimers_disease_facts_and_figur es.asp? type=alzchptfooter) [1,2]. The situation in China is perhaps even worse and more alarming because of its population in the world, which is rapidly aging. While there is little official epidemiological record, China may already have more than 6 8 million AD patients today. What’s more, the overall life-expectancy for Chinese is now about 76 years (http://en.wikipedia.org/wiki/List_of_countries_by_life_ expectancy), but it will catch up the current mid-80s records in most western/developed countries within 10 years or so. Together with other problems and difficulties (e.g., the one-child policy), China may soon face one of the greatest socioeconomic and healthcare challenges in her journey to modernization (http://charls.ccer.edu.cn). AD is pathologically characterized by amyloid plaques, neurofibrillary tangles, neuritic pathology, gliosis, and neuronal and synaptic loss in vulnerable brain regions especially in the limbic and neocortical areas [3-5]. Aging is the greatest risk factor, while vascular and metabolic deficits, trauma, inflammation, environmental insults, genetic predisposition, and physiological “wasting” of cognitive and physical reserve are also potential etiological factors. Many theories have been proposed for the pathogenesis of this disease. Among all, the amyloid hypothesis emphasizes accumulation of β-amyloid peptides (Aβ) being the leading pathogenic factor. The mitochondria/metabolic stress cascade hypothesis considers age-inherent metabolic failure or oxidative damages to mitochondrial DNA, RNA, lipid and protein as the primary pathogenic mechanism. The cognitive reserve hypothesis suggests that reduced brain use plays an important role in dementia and AD development. The calcium hypothesis posits Ca homeostatic deregulation contributing to neuronal death and functional decline in brain aging and AD [5-9]. Evidence exists in supporting each of these hypotheses, reflecting the nature of complexity and multi-dimensional abnormalities of this disease. At present, efforts are particularly needed to identify the fundamental molecular/cellular mechanism that may unify the risk factors, pathological manifestations and functional loss in this disease [8,9]. Because there are no