Abstract from Nature Medicine
The balance between detrimental, pro-aging, often stochastic processes and counteracting homeostatic mechanisms largely determines the progression of aging. There is substantial evidence suggesting that the endocannabinoid system (ECS) is part of the latter system because it modulates the physiological processes underlying aging1, 2. The activity of the ECS declines during aging, as CB1 receptor expression and coupling to G proteins are reduced in the brain tissues of older animals3, 4, 5 and the levels of the major endocannabinoid 2-arachidonoylglycerol (2-AG) are lower6. However, a direct link between endocannabinoid tone and aging symptoms has not been demonstrated. Here we show that a low dose of Δ9-tetrahydrocannabinol (THC) reversed the age-related decline in cognitive performance of mice aged 12 and 18 months. This behavioral effect was accompanied by enhanced expression of synaptic marker proteins and increased hippocampal spine density. THC treatment restored hippocampal gene transcription patterns such that the expression profiles of THC-treated mice aged 12 months closely resembled those of THC-free animals aged 2 months. The transcriptional effects of THC were critically dependent on glutamatergic CB1 receptors and histone acetylation, as their inhibition blocked the beneficial effects of THC. Thus, restoration of CB1 signaling in old individuals could be an effective strategy to treat age-related cognitive impairments.
In this Sept. 30, 2016, file photo, a harvester examines marijuana buds from a trimming machine near Corvallis, Ore. THE CANADIAN PRESS/AP Photo/Andrew Selsky
From CTVNews Published Tuesday, May 9, 2017 7:01PM EDT
New European research on animals suggests that cannabis could help reverse the aging process in the brain, opening up the possibility that the drug could be used in the treatment of dementia.
Led by researchers from the University of Bonn, Germany, along with a team from The Hebrew University of Jerusalem, Israel, the new study looked at the effects of THC on mice, an animal which has a relatively short life expectancy in nature and shows pronounced cognitive deficits even at 12 months of age.
The researchers gave the mice a small quantity of THC, the active ingredient in the hemp plant (cannabis), at age two, 12 and 18 months over a period of four weeks.
The mice were given only a small amount to ensure there was no intoxicating effect.
The animals were then tested on their learning capacity and memory performance, including their orientation skills and the recognition of other mice.
The team found that mice given cannabis showed cognitive functions equal to those seen in the two-month-old control animals, however those who were given a placebo showed the natural learning and memory losses associated with aging.
“The treatment completely reversed the loss of performance in the old animals,” reported one of the study’s authors Prof. Andreas Zimmer from the University of Bonn.
After examining the brain tissue and gene activity of the mice given THC further, the team also found that the molecular signature — the sets of genes, proteins, and genetic variants of the mice — was no longer in line with the molecular signature of old animals, but instead showed similarities to that of young animals.
The number of links between the nerve cells in the brain, which are important for learning ability, had also increased to levels more associated with younger mice: “It looked as though the THC treatment turned back the molecular clock,” says Zimmer.
The team are now planning on taking their research to the next stage to see if THC can also reverse aging processes in the brain and increase cognitive ability in humans, with the North Rhine-Westphalia science minister Svenja Schulze commenting, “Although there is a long path from mice to humans, I feel extremely positive about the prospect that THC could be used to treat dementia, for instance.”
Many countries and U.S. states have recently started relaxing their cannabis laws, with the use of medical marijuana, for example to help relieve pain, growing in popularity.
The results can be found published online in the journal Nature Medicine.