Biomarkers of neurodegenerative disorders: How good are they?

Abstract

Biomarkers are very important indicators of normal and abnormal biological processes. Specific changes in pathologies, biochemistries and genetics can give us comprehensive information regarding the nature of any particular disease. A good biomarker should be precise and reliable, distinguishable between normal and interested disease, and differential between different diseases. It is believed that biomarkers have great potential in predicting chances for diseases, aiding in early diagnosis, and setting standards for the development of new remedies to treat diseases. New technologies have enabled scientists to identify biomarkers of several different neurodegenerative diseases. The followings, for instance, are only a few of the many new biomarkers that have been recently identified: the phosphorylated tau protein and aggregated β-amyloid peptide for Alzheimer's disease (AD), α-synuclein contained Lewy bodies and altered dopamine transporter (DAT) imaging for Parkinson's disease (PD), SOD mutations for familial amyotrophic lateral sclerosis (ALS), and CAG repeats resulted from Huntington's gene mutations in Huntington's disease (HD). This article will focus on the most-recent findings of biomarkers belonging to the four mentioned neurodegenerative diseases.

Antioxidant and Antigenotoxic Activities of Purple Grape Juice—Organic and Conventional—in Adult Rats

“…37 Clinical studies demonstrated a reduction of SOD activity in Parkinsonism associated with other neurodegenerative disorders, showing the key role played by this enzyme in fighting free radicals produced in the brain. 38,39 In our results, we observed that in some tissues (cerebral cortex, hippocampus, liver, and plasma) CCl 4 decreased SOD activity. According to Chang et al, 40 the decrease of SOD activity by CCl 4 could result from the consumption of SOD to compensate excessive peroxyl radicals derived from CCl 4 's metabolism.…”

Can the retina be used to diagnose and plot the progression of Alzheimer's disease?

“…Biomarkers are a subclass of endogenously occurring indicators, which signify the pathological state (Rachakonda et al 2004) 8 . An ideal biomarker is specific, sensitive, noninvasive, inexpensive, reproducible, suitable for large-scale population screening and readily available.…”

ADP-Ribosylation Factor Guanine Nucleotide-Exchange Factor 2 (ARFGEF2): A New Potential Biomarker in Huntington's Disease

“…4 Biomarkers are of extreme relevance in chronic neurodegenerative diseases such as HD, since it is not possible to sample brain tissue to monitor pathophysiological processes. 5 Tremendous efforts have been made to identify neuropathological, biochemical and genetic biomarkers of these diseases, with the intention of establishing diagnosis earlier in the disease course to enable surveillance of the rate of progression and response to treatment. The mutation that encodes CAG expansion is a definitive diagnostic marker for HD, but provides no information on the clinical progression of HD.…”