Research Roundup: Fishy feelings, young blood and Alzheimer’s disease and more!

Welcome to this week’s Research Roundup. These Friday posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

  • Fish with feelings. Human emotion can be directly measured using interviews or surveys; however, the assessment of emotion in animals is not as simple. Fortunately, the behavioral, physiologic, neurologic, and genetic changes that accompany emotion can be assessed instead. For example, previous work has shown that highly evolved mammals, such as primates, display “jealous” behaviors. The occurrence of emotions in simpler animals, such as fish, has been debated for many years. A new study showed that Gilthead Sea Bream, a type of fish, displayed emotional reactions (i.e., investigative or escape behaviors) to stimuli presented under favorable or aversive conditions. Emotion was also assessed in the fish by measuring levels of cortisol and the activation of brain areas associated with positive and negative emotional states. This research indicates that simple animals may possess the cognitive ability to use emotions to guide their actions. This research was published in the journal Scientific Reports.
Gilthead Sea Bream, Image credit: Aqua EcoSystems
  • Results of first trial of infusing of young blood are in. Previous research in mice has suggested that infusion of young blood, through parabiosis, can improve the health of older mice. This work eventually led to the first small scale clinical trial in humans – involving the transfusion of young blood to older individuals with Alzheimer’s disease. Original reports of the results of that study were glowing – reporting modest improvements in the daily lives of these Alzheimer patients. However, subsequent scientific discourse has highlighted glaring problems with the experimental design and conduct of this clinical trial – including a high risk of bias and the lack of appropriate controls. This is a good example of the self correcting nature of science – and while this treatment still holds promise – the verdict on its efficacy in humans is still out.
  • MouseLight helps researchers unravel secrets of the brain. Researchers at the Howard Hughes Medical Institute Janelia Research Campus have created a 3D map of 300 mouse neurons, with the aim of adding another 700 in 2018. However, even this feat only scratches the surface of the 70 million neurons typically found in a mouse’s brain. Scientists injected a virus into the brains of mice which would infect a few cells and cause them to produce fluorescent proteins; they then imaged the brain with high-resolution microscopes and turned the resulting images into 3D computer models. They found many of the axons (slender projections of the neuron) were up to half a metre in length and stretched into unexpected regions of the brain, for example the neurons associated with taste also stretched into areas controlling movement and touch. More information on the project is available on the MouseLight website.
Brain of mouse lit up by MouseLight, Image Credit MouseLight
  • Tail regeneration in gecko and spinal cord injury. Lizard tails are an extension of their spinal cord and they have the ability to regenerate their tails, and thus spinal cords, when a section becomes detached. Researchers at University of Guelph have identified a special type of stem cell — the radial glial cell —  which allows geckos to regenerate their tail whenever it is detached and make a brand new portion of the spinal cord. Unlike geckos, humans do not have the radial glial cells and often make scar tissue following spinal cord injury rather than growing new cells. This specific research and related projects may one day help humans, and other mammals, to regenerate spinal cords  — which is not currently possible. This research was published in The Journal of Comparative Neurology.
  • Donor organs created by rebuilding pig livers. We have previously written about the use of genetically modified pigs and their valuable role in attenuating the organ crisis here. Now, a new method which uses pig organs as a scaffold for new organs – gives further promise to an end of the organ crisis. This method involves using a pig organ, dissolving the cells away from it, leaving the organ’s protein scaffold intact. Then, the scaffold is re-infused with human cells creating a “human organ” with a pig scaffold. This approach is promising because it reduces the likelihood of organ rejection. This research was presented at a meeting of the American Association for the Study of Liver Diseases in Washington DC this month.