Knoth et al. as reported in PLoS One has been able to study the growth and death of adult human brain cells (neurogenesis). He uses the double cortin (DCX), a protein involved in cell movement and the extension of neuronal processes.
His study focused on the hippocampal cells included a large number of subjects between 0 to 100 years of age. It is believed that neurogenesis declines with age in both man, rodents and other primates.
The hippocampus is part of the limbic system(emotional center) and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Change in the growth rate of these cells can profoundly affect memory, learning, recall of information and emotional well being.
The cell marker DCX found that DCX+ cells decreased with age and there seems to be about a tenfold decrease from puberty to old age.
Morphology of DCX+ cells observed by Knoth et al.ranging from immature (lt) to mature cell (rt)
The oldest age at which DCX+ cells were still found to be proliferating depended on which endogenous marker of proliferation was used (Ki67 – 38yr, Mcm2 – 65yr, PCNA – oldest age). It is possible that major proliferation of hippocampal cells ends in middle age and that DCX+ cells found in the oldest subjects are the result of a very slow cellular maturation process.
Possibly there is a wide variance in human brain tissue that may or may not be age dependent, but if the research was ex[anded to include more seniors that lead a healthy active life style and were well hydrated these cells may not decrease has rapidly.
Does brain cell proliferation occur in old age more slowly? Much more work is needed.
Could this be a help to changing the aging of the human brain? Time will tell.