A new study by Harvard neuroscientist Jeffrey Macklis and his colleagues suggests that it is possible to transplant fetal neurons in a part of the mouse brain that usually does not generate new brain cells, and will repair the abnormal circuits. In this case, investigators repair a genetic defect that causes obesity, but it was not the purpose of their work was to establish proof of principle that transplanted neurons can integrate into existing brain circuitry and restore defective.
This type of genetically modified mouse is commonly used as an animal model for researching obesity, diabetes, and dyslipidemia, and is known as the "db/db mouse".
There are only two areas of the brain that are known to normally undergo ongoing large-scale neuronal replacement during adulthood on a cellular level -- so-called ‘neurogenesis,’ or the birth of new neurons -- the olfactory bulb and the subregion of the hippocampus called the dentate gyrus, with emerging evidence of lower level ongoing neurogenesis in the hypothalamus.
To make the transplanted cells in exactly the correct region of the hypothalamus and microscopic receptor, used a technique called high-resolution microscopy of ultrasound, creating what Macklis called "chimeric hypothalamus"
