成人大片

成人大片 researchers have found important evidence supporting their theory that a deficiency of active iron in the brain is an important factor in Alzheimer鈥檚 disease.

Mutations in a small number of genes can cause an inherited form of Alzheimer鈥檚 disease that afflicts people when they are relatively young. Currently, the dominant theory of what causes Alzheimer鈥檚 disease is that these mutated genes change the way a small protein fragment, Amyloid beta, is produced. Many researchers believe that Amyloid beta can build up, become toxic, and eventually destroy brain function.

The new study - published in the Journal of Alzheimer鈥檚 Disease - follows the proposal of a group of Adelaide scientists and their collaborators who predicted that the main gene involved in inherited Alzheimer鈥檚 disease, PSEN1, would be important for supplying iron to brain cells.

"The active iron signal seems to clearly distinguish Alzheimer鈥檚 disease brains from other brains that had buildup of Amyloid beta but did not have memory problems,鈥�Dr Michael Lardelli, School of Biological Sciences' Alzheimer's Disease Genetics Laboratory

Dr Michael Lardelli, from the 成人大片鈥檚 Alzheimer鈥檚 Disease Genetics Laboratory in the School of Biological Sciences, said: 鈥淏rain cells are a bit like people when it comes to getting the nutrition they need. Just as people have acid in their stomachs to help break down food, cells have microscopic acid-filled stomachs called 鈥榣ysosomes鈥�.

鈥淚f the lysosome is not acidic enough, the cell will have difficulty absorbing nutrients from outside. The cell will also have difficulty recycling materials it no longer needs in order to reuse them for other tasks. Research by others has shown that when the PSEN1 gene is mutated, cells鈥� lysosomes cannot become properly acidic.

鈥淚ron is very, very important for cell survival. And it turns out that having sufficiently acidic lysosomes is very important for providing iron to cells. Without sufficient active iron, the cell鈥檚 powerhouses - its mitochondria - malfunction and cause damage. The mitochondria become a bit like microscopic nuclear powerplants that are leaking radioactivity.鈥�

The team had to develop a new method for detecting evidence that the balance of active iron in brains was upset.

鈥淢ost of this was done by PhD. student, Nhi Hin, who won our university鈥檚 Doctoral Research Medal for her work, and her supervisor, Dr Stephen Pederson,鈥欌�� said Dr Lardelli.

鈥淲hen we used the new technique to analyse the brain data we already had from our Alzheimer鈥檚 mutant fish, we could see clear evidence for the iron disturbance we had predicted. Nhi Hin then applied the same technique to data from the brains of people who had died with Alzheimer鈥檚 disease. There was a very strong signal there too. In fact, the active iron signal seems to clearly distinguish Alzheimer鈥檚 disease brains from other brains that had buildup of Amyloid beta but did not have memory problems.鈥�

Dr Lardelli said the findings had implications for those at risk of developing Alzheimer鈥檚 disease.

鈥淚t has long been known that having sufficient iron in your diet is very important for mental function and overall health. But iron is both a blessing and a curse,鈥欌�� he said.

鈥淗aving too much iron can damage your body. So, people should not start taking iron supplements unless their doctor recommends they do so. In the meantime, we need more research to find a way to overcome the defective acidification problem of the lysosomes. That would likely solve the brain鈥檚 iron problem and other cell nutrition problems that may be contributing to Alzheimer鈥檚 disease.鈥�

听