New research by joint team of the US and Israel scientists has demonstrated that transplanting fetal neurons into the brain of mice with genetic defect restored abnormal circuits. Although the researchers worked with a defect causing obesity, to repair it was not their primary goal. They aimed to challenge the idea that abnormal parts of mammalian brain cannot be repaired and to show that transplanted fetal neurons can restore improperly functioning brain circuits. The study has been recently published online in the journal Science.
In the research, mutant mice were used. They were genetically engineered so that they lacked receptor for hormone called leptin. This hormone is responsible for appetite and body weight regulation. The mice lacking this receptor became extremely obese and developed diabetes.
In the experiment, the mutant mice were transplanted into their hypothalamus neurons taken from hypothalamus of fetuses of healthy mice at a particular development stage. As a result, the transplant helped repair the defective brain circuits. The mutant mice gained the ability to respond to leptin, and their weight significantly decreased and turned out to be lower than in the control group that had not received transplant.
To track the transplants in the recipients’ mice hypothalamus, the researchers used several markers. As a result, they observed that transplanted neurons specialized into the cell types found in hypothalamus and formed connections with other neurons. Like normal neurons, these neurons had the ability to respond to leptin.
The researchers hope the finding will pave way for treating diseases and states such as Parkinson’s, ALS, autism, epilepsy, spinal cord injury etc. Although the previous experiments in treating Parkinson’s with fetal stem cell transplants have not brought anticipated results, the researchers expect that harvesting fetal neurons exactly at the stage when they are going to differentiate into different hypothalamus neuron types may be the key for effective treatment.