Until now diseases like schizophrenia and bipolar disorder have been difficult to study biologically, since this would entail taking samples from the patient's brain.
But new research findings from Örebro University in Sweden show that it is just as good to study a certain type of skin cells, since they function in a way that is similar to a type of brain cells that are suspected of playing a major role in both disorders.
"Among other benefits, this makes it considerably easier to develop and test new drugs," says Ravi Vumma, and the head of the research group Nikolaos Venizelos who is presenting the findings in the journal Neuroscience Letters.
One of the causes of schizophrenia and bipolar disorder (previously called manic-depressive syndrome) is assumed to be that the level of important transmitter substances in the brain is too low, which negatively impacts the transmission of signals. That, in turn, is because the cells in the blood-brain barrier are not transporting enough of the amino acids that are needed for the brain to be able to produce signal substances like dopamine, noradrenalin, and serotonin.
"Altered transport of the amino acids tyrosine and tryptophan may be one explanation for the disrupted signal transmission in patients with schizophrenia and bipolar disorder," Ravi Vumma explains.
We have therefore mapped how the transport of the two amino acids takes place, what paths they take into the cell. Various amino acids use different transport systems, and to enhance our knowledge about schizophrenia and bipolar disorder it is necessary to identify which systems are relevant for tyrosine and tryptophan.
Moreover, we want to find out whether connective tissue cells in the skin, fibroblasts, transport amino acids in the same way as endothelial cells in the brain, as this would constitute a dramatic enhancement of our ability to study how substances pass through the blood-brain barrier. The two cell types have a similar membrane function, to close out undesirable substances and only transport substances the body needs.