Ultrasound to the brain induces noninvasive and safe hibernation in mice – and maybe humans

Amazing stuff! It also allows for precise control of the depth and duration of ultrasound-induced hypothermia.

"... The team created an ultrasound emitter small enough to be mounted on the heads of mice as they went about their day. This could fire off 10-second pulses of ultrasound directed at the preoptic area of the hypothalamus, which instantly triggered symptoms of torpor in the animals. That includes a drop in body temperature by 3 to 3.5 °C (5.4 to 6.3 °F), as well as reduced heart rate and oxygen consumption. The animals woke up naturally after a few hours. ..."

"... In the rat, which does not naturally go into torpor or hibernation, the team delivered ultrasound to the hypothalamus preoptic area and found a decrease in skin temperature, particularly in the brown adipose tissue region, as well as about a 1 degree C drop in core body temperature, resembling natural torpor. ..."

From the abstract:

"Torpor is an energy-conserving state in which animals dramatically decrease their metabolic rate and body temperature to survive harsh environmental conditions. Here, we report the noninvasive, precise and safe induction of a torpor-like hypothermic and hypometabolic state in rodents by remote transcranial ultrasound stimulation at the hypothalamus preoptic area (POA). We achieve a long-lasting (>24 h) torpor-like state in mice via closed-loop feedback control of ultrasound stimulation with automated detection of body temperature. Ultrasound-induced hypothermia and hypometabolism (UIH) is triggered by activation of POA neurons, involves the dorsomedial hypothalamus as a downstream brain region and subsequent inhibition of thermogenic brown adipose tissue. Single-nucleus RNA-sequencing of POA neurons reveals TRPM2 as an ultrasound-sensitive ion channel, the knockdown of which suppresses UIH. We also demonstrate that UIH is feasible in a non-torpid animal, the rat. Our findings establish UIH as a promising technology for the noninvasive and safe induction of a torpor-like state."

Ultrasound to the brain induces hibernation in mice – and maybe humans (secondary news source)

Induction of a torpor-like state with ultrasound (primary news source) Chen’s team used ultrasound to safely, noninvasively induce a torpor-like state in mice, rats

Induction of a torpor-like hypothermic and hypometabolic state in rodents by ultrasound (open access)

Fig. 2: Ultrasound stimulation of POA induces hypothermia and hypometabolism.