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Cannabis reverses aging processes in brains of mice


Researchers restore the memory performance of Methuselah mice to a juvenile stage

Next step: clinical trials in humans to see whether THC reverses aging processes and increases cognitive ability

Memory performance decreases with increasing age. Cannabis can reverse these aging processes in the brain. This was shown in mice by scientists at the University of Bonn with their colleagues at the Hebrew University of Jerusalem. Old animals were able to regress to the state of two-month-old mice with a prolonged low-dose treatment with a cannabis active ingredient. This opens up new options, for instance, when it comes to treating dementia. The results are now presented in the journal Nature Medicine.

Like any other organ, our brain ages. As a result, our cognitive abilities decrease with increasing age. Thus it becomes more difficult to learn new things or devote attention to several things at the same time. This process is normal, but can also promote dementia. Researchers have long been looking for ways to slow down or even reverse this process.

Scientists at the University of Bonn and the Hebrew University of Jerusalem have now achieved this in mice. With their short life expectancy, these animals display pronounced cognitive deficits even at twelve months of age. The researchers administered a small quantity of THC, the active ingredient in the hemp plant (cannabis), to mice aged two, twelve and 18 months over a period of four weeks.

Afterwards, they tested learning capacity and memory performance in the animals – including, for instance, orientation skills and the recognition of other mice. Mice that were only given a placebo displayed natural age-dependent learning and memory losses. In contrast, the cognitive functions of the animals treated with cannabis were just as good as the two-month-old control animals. “The treatment completely reversed the loss of performance in the old animals,” reported Prof. Andreas Zimmer from the Institute of Molecular Psychiatry at the University of Bonn and member of the Cluster of Excellence ImmunoSensation.

Years of meticulous research

This treatment success is the result of years of meticulous research. First, the scientists discovered that the brain ages much faster when mice do not possess any functional receptors for THC. These cannabinoid 1 (CB1) receptors are proteins to which the substances dock and thus trigger a signal chain. CB1 is also the reason for the intoxicating effect of THC in cannabis products, such as hashish or marihuana, which accumulate at the receptor. THC imitates the effect of cannabinoids produced naturally in the body, which fulfil important functions in the brain. “With increasing age, the quantity of the cannabinoids naturally formed in the brain reduces,” says Prof. Zimmer. “When the activity of the cannabinoid system declines, we find rapid aging in the brain.”

To discover precisely what effect the THC treatment has in old mice, researchers at the Hebrew University of Jerusalem, led by Dr. Mona Dvir-Ginzberg and the late Prof. Itai Bab, examined the epigenetic changes in brains of aged mice treated with THC.

"The THC treatment induced molecular and epigenetic changes, which no longer corresponded to that of untreated old animals, but rather were similar to what we see in young animals," said Dr. Mona Dvir-Ginzberg from the Institute of Dental Sciences, in the Faculty of Dental Medicine at The Hebrew University of Jerusalem.

Moreover, the number of links between the nerve cells in the brain also increased again, which is an important prerequisite for learning ability. “It looked as though the THC treatment turned back the molecular clock,” says Zimmer.

Next step: clinical trial on humans

A low dose of the administered THC was chosen so that there was no intoxicating effect in the mice. Cannabis products are already permitted as medications, for instance as pain relief. As a next step, the researchers want to conduct a clinical trial to investigate whether THC also reverses aging processes in the brain in humans and can increase cognitive ability.

CITATION: A chronic low dose of delta9-tetrahydrocannabinol (THC) restores cognitive function in old mice, Nature Medicine, DOI: 10.1038/nm.4311 (link:

Cannabis reverses aging processes in brains of mice

Both push and pull drive our Galaxy’s race through space


Discovery of the “Dipole Repeller” confirms that both attraction and repulsion are at play in our extragalactic neighborhood

Although we can’t feel it, we’re in constant motion: the earth spins on its axis at about 1,600 km/h; it orbits around the sun at about 100,000 km/h; the sun orbits our Milky Way galaxy at about 850,000 km/h; and the Milky Way galaxy and its companion galaxy Andromeda are moving with respect to the expanding universe at roughly 2 million km/h (630 km per second). But what is propelling the Milky Way’s race through space?

Until now, scientists assumed that a dense region of the universe is pulling us toward it, in the same way that gravity made Newton’s apple fall to earth. The initial “prime suspect” was called the Great Attractor, a region of a half dozen rich clusters of galaxies 150 million lightyears from the Milky Way. Soon after, attention was drawn to an area of more than two dozen rich clusters, called the Shapley Concentration, which sits 600 million lightyears beyond the Great Attractor.

Now researchers led by Prof. Yehuda Hoffman at the Hebrew University of Jerusalem report that our galaxy is not only being pulled, but also pushed. In a new study in the forthcoming issue of Nature Astronomy, they describe a previously unknown, very large region in our extragalactic neighborhood. Largely devoid of galaxies, this void exerts a repelling force on our Local Group of galaxies.

“By 3-d mapping the flow of galaxies through space, we found that our Milky Way galaxy is speeding away from a large, previously unidentified region of low density. Because it repels rather than attracts, we call this region the Dipole Repeller,” said Prof. Yehuda Hoffman. “In addition to being pulled towards the known Shapley Concentration, we are also being pushed away from the newly discovered Dipole Repeller. Thus it has become apparent that push and pull are of comparable importance at our location.”

PHOTOS and VIDEO are available at Use of these materials is permitted on condition of respecting the publication embargo and including the proper credit information.

The presence of such a low density region has been suggested previously, but confirming the absence of galaxies by observation has proved challenging. But in this new study, Hoffman, at the Hebrew university’s Racah Institutes of Physics, working with colleagues in the USA and France, tried a different approach.

Using powerful telescopes, among them the Hubble Space Telescope, they constructed a 3-dimensional map of the galaxy flow field. Flows are direct responses to the distribution of matter, away from regions that are relatively empty and toward regions of mass concentration; the large scale structure of the universe is encoded in the flow field of galaxies. They studied the peculiar velocities – those in excess of the Universe’s rate of expansion – of galaxies around the Milky Way, combining different datasets of peculiar velocities with a rigorous statistical analysis of their properties. They thereby inferred the underlying mass distribution that consists of dark matter and luminous galaxies — over-dense regions that attract and under-dense ones that repel.

By identifying the Dipole Repeller, the researchers were able to reconcile both the direction of the Milky Way’s motion and its magnitude. They expect that future ultra-sensitive surveys at optical, near-infrared and radio wavelengths will directly identify the few galaxies expected to lie in this void, and directly confirm the void associated with the Dipole Repeller.

Hoffman’s collaborators include Daniel Pomarède, Institut de Recherche sur les Lois Fondamentales de l’Univers, CEA, Université Paris-Saclay, Gif-sur-Yvette, France; R. Brent Tully, Institute for Astronomy (IFA), University of Hawaii, USA; and Hélène M. Courtois, IPN Lyon, University of Lyon, France.

CITATION: The dipole repeller. Yehuda Hoffman, Daniel Pomarède, R. Brent Tully and Hélène M. Courtois. Nature Astronomy, Advance Online Publication January 30, 2017. doi: 10.1038/s41550-016-0036

SUPPORT: The researchers thank the Israel Science Foundation (1013/12), the Institut Universitaire de France, the US National Science Foundation, Space Telescope Science Institute (for Observations with Hubble Space Telescope), the Jet Propulsion Lab (for observations with Spitzer Space Telescope) and NASA (for analysis of data from the Wide-field Infrared Survey Explorer).

Both push and pull drive our Galaxy’s race through space
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