Peripheral injection of human umbilical cord blood stimulates neurogenesis in the aged rat brain.
BACKGROUND
Neurogenesis continues to occur throughout life but dramatically decreases with increasing age. This decrease is mostly related to a decline in proliferative activity as a result of an impoverishment of the microenvironment of the aged brain, including a reduction in trophic factors and increased inflammation.


RESULTS
We determined that human umbilical cord blood mononuclear cells (UCBMC) given peripherally, by an intravenous injection, could rejuvenate the proliferative activity of the aged neural stem/progenitor cells. This increase in proliferation lasted for at least 15 days after the delivery of the UCBMC. Along with the increase in proliferation following UCBMC treatment, an increase in neurogenesis was also found in the aged animals. The increase in neurogenesis as a result of UCBMC treatment seemed to be due to a decrease in inflammation, as a decrease in the number of activated microglia was found and this decrease correlated with the increase in neurogenesis.


CONCLUSIONS
The results demonstrate that a single intravenous injection of UCBMC in aged rats can significantly improve the microenvironment of the aged hippocampus and rejuvenate the aged neural stem/progenitor cells. Our results raise the possibility of a peripherally administered cell therapy as an effective approach to improve the microenvironment of the aged brain.
Bachstetter
Adam D
AD
Department of Molecular Pharmacology and Physiology, University of South Florida, College of Medicine, Tampa, FL 33612, USA. abachste@health.usf.edu
Pabon
Mibel M
MM
Cole
Michael J
MJ
Hudson
Charles E
CE
Sanberg
Paul R
PR
Willing
Alison E
AE
Bickford
Paula C
PC
Gemma
Carmelina
C
D000375:Aging / Q000473:pathology*; D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D049109:Cell Proliferation; D016922:Cellular Senescence / Q000502:physiology; D005312:Fetal Blood / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology*; D006801:Humans; D007275:Injections, Intravenous; D007963:Leukocytes, Mononuclear / Q000166:cytology; D008297:Male; D017628:Microglia / Q000166:cytology; D009474:Neurons / Q000166:cytology*; D010641:Phenotype; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology*