Repeated Intravenous Administration of Human Neural Stem Cells Encoding Choline Acetyltransferase Gene Exhibits Anti-ageing Activities Displaying Enhanced Cognitive and Physical Functions

Abstract

Ageing may be characterized by progressive loss of cognitive function as well as decrease in physical activities, in addition to change in appearance. Previously, we reported that intracerebroventricular transplantation of a human neural stem cell (NSC) line (F3) over-expressing choline acetyltransferase (F3.ChAT) gene, an enzyme responsible for acetylcholine synthesis, markedly improved cognitive function and physical activity of aged animals by enhancing acetylcholine and growth factors (GFs) and neurotrophic factors (NFs). In the present study, 10-month-old F344 rats were intravenously transplanted with F3 or F3.ChAT NSCs (1 x 106 cells) once a month to 21st month of age when the cumulative mortality reached 20%, and physical activity and learning/memory function were investigated, in addition to the analyses of brain acetylcholine concentration, and cholinergic and dopaminergic system restoration. Neuroprotective and neuroregenerative activities of stem cells were also confirmed by analyzing oxidative damages, neuronal skeletal protein, angiogenesis, brain and muscle weights, and proliferating host stem cells. Stem cells markedly improved both the cognitive (passive avoidance and water-maze performances) and physical (locomotor and rota-rod activities) functions, in parallel with the elevation of acetylcholine levels in cerebrospinal fluid and in muscles, in which F3.ChAT cells were superior to F3 parental cells. Stem cell transplantation down-regulated CCL11, leading to restoration of microtubule-associated protein 2 as well as functional markers of cholinergic and dopaminergic systems, and preserved brain and muscular capillaries, recovering muscle mass. In addition, stem cells enhanced antioxidative capacity, attenuating oxidative damage of multiple organs including muscles and the brain. The results indicate that NSCs over-expressing ChAT gene improve cognitive function and physical activity of ageing animals by protecting and recovering functions of multiple organs including cholinergic and dopaminergic systems as well as muscles from oxidative injuries through secretion of acetylcholine and GFs/NFs, increased antioxidant elements, and enhanced blood flow.