Jun Liu
Alzheimer’s Disease (AD) is a neurodegenerative disorder mainly characterized by β-amyloid deposit, τ-hyperphosphorylation and neuron loss with no curative treatments. In recent years, the main efforts of multinational pharmaceutical companies have been focused on reducing the aggregation of Aβ and τ-proteins but with repeated defeats. According to statistics of Adis R&D, between 1998 and 2014, major pharmaceutical companies launched a total of 123 drugs for AD but only three drugs and one combination therapy program have been approved by the FDA. However, without exception, none of these 123 drugs can cure AD and even delay the progression of the disease. So we should shift our focus from alleviating the AD-like pathologies to neuroprotection, which means the preservation of neuronal structure and/or function. As far as we know, there are some therapeutic strategies of neuroprotection for AD, such as the application of NMDA receptor antagonists, Acetylcholinesterase Inhibitors (ACEIs), anti-inflammatory agents, antioxidants, neurotrophins and Chinese medicine and so on. Our research group has found that neurotropin (a non-protein bioactive agent extracted from rabbit inflamed skins inoculated with Vaccinia virus vaccine), GQDG (Graphene Quantum Dot Conjugated with neuroprotective peptide-glycine-prolineglutamate), edaravone, EGb761 (Ginkgo Biloba extract) and β-sitosterol exerted potent neuroprotective effects in AD. In conclusion, a single cure for AD is unlikely to be found and multi-target therapies should be addressed. Neurodegenerative diseases are incurable and debilitating conditions that result in progressive degeneration and/or death of nerve cells. The huge variety of neurodegenerative diseases, in terms of pathological characteristics, symptoms, and treatments, makes it very difficult to classify them in general terms. Taking into account the different neurodegenerative diseases, one of the parameters we can considerer is prevalence. According to this, there are two most prevalent neurodegenerative diseases: Alzheimer’s disease (AD) and Parkinson’s disease (PD). This affirmation is substantiated in the literature. In 2015, there were 46.8 million AD patients worldwide with direct and indirect costs to society of 81,800 million USD, and in 2016 there were 6.1 million individuals with PD worldwide. Dementia is a major symptom of AD, consisting of memory impairment accompanied by dysfunction, which is responsible for the inability to develop daily life activities. Vascular dementia is quite important since it is considered the second most common cause of dementia in the aging population and also is thought to underlie AD. This disorder consists of a decline in cognitive skills caused by blocking or reduction of blood flow to the brain. On the other hand, PD is characterized by motor symptoms such as bradykinesia/akinesia, resting tremor, rigidity, and postural abnormalities, and non-motor symptoms such as dementia, hyposmia, depression, and emotional changes.
