Andrew Johnson and team at National Institute of Health/National Heart, Lung and Blood Institute believe there must be something substantially different in young blood compared to old. They conducted an extensive study using thousands of patient blood samples that was then replicated.
The study identified 1,497 genes in blood cells and/or brain tissue that showed significantly differential expression patterns in older individuals when compared to younger individuals.
- They had analyzed the blood samples transcriptome, a measurement of the RNA transcripts from each gene. The compilation of RNA transcripts is a reflection of the relative expression levels of the genome at a given point in time.
- They chose the transcriptome (the set of all RNA molecules, including mRNA, rRNA, tRNA, and other non-coding RNA transcribed in one cell or a population of cells), as all the cells in an organism will have the same DNA and this DNA does not generally change during the person’s lifetime, thus making DNA genomic analysis less useful for an age-related study.
- What does change over a person’s lifetime is modifications of DNA, which genes are expressed from the DNA and the relative levels of expression of each gene.
- This study was published in Nature Communications. It used blood cells and brain tissue to examine age-associated changes in gene expression.
- Gene expression can either be negatively or positively expressed at a lower or higher level in relation to chronological age.
- Three distinct groups of genes were negatively correlated with chronological age.
- An interesting finding in this study involved epigenetic patterns, specifically methylation on cytosines.
- Epigenetics doesn’t change the underlying pattern of DNA base pairs, but instructs how a gene is to be expressed.
- The 1,497 genes identified as being associated with chronological age offer a plethora of new targets to better understand the aging process and age-related diseases.
- With current progress in gene therapy and drug fields it’s possible that some of these 1,497 genes could potentially be manipulated to ameliorate many age-related diseases.