American research reveals that the loss of “social memory” in Alzheimer’s disease could depend on the deterioration of perineuronal networks
For many patients affected by Alzheimer’s and for their family members and caregivers, one of the most distressing symptoms is not just the loss of recent memory, but the inability to recognize loved ones. This particular form of amnesia, called “social memory”, represents a profound breaking point in the lives of those living with the disease and their family members who care for them.
While it is true that in recent years Alzheimer’s research has made giant strides in understanding the disease, identifying early symptoms and slowing its progression, much is still unclear to us. A new piece comes from the United States, where a group of researchers tried to explain why we end up losing the so-called social memory and how, at least in theory, to counteract this form of amnesia.
A study conducted by researchers from the University of Virginia School of Medicine and the School of Neuroscience at Virginia Tech in Blacksburg have identified the deterioration of the “perineuronal networks” in the brain as possible cause of this type of memory loss. And, even more interestingly, it showed that some drugs already being studied for tumors and arthritis could protect themthus preserving the memory of loved ones.
The “armor” that protects memories
—
Perineuronal networks are protein structures that form a sort of matrix around the neurons. They work like armor: stabilize synaptic connectionsregulate brain plasticity and protect neurons from oxidative stress. The group led by Professor Harald Sontheimer had already in the past discovery that these networks are particularly important in some regions of thehippocampusthe area where memories are formed and stored. Since that study, researchers have hypothesized that their malfunction could contribute to the progression of Alzheimer’s.
The new study, published in the journal Alzheimer’s & Dementiaconfirmed that hypothesis: when perineuronal networks degrade in the CA2 region of the hippocampus, mice lose the ability to remember other individuals of their species. However, it is not a total loss of memory: they retain the ability to recognize objects and environments. What disappears, in practice, is only the memory of social relationships. This, according to US researchers, faithfully reflects what happens in people: those who suffer from Alzheimer’s he often stops before recognizing family members and only later does he show widespread deterioration of memory.
The role of drugs in protecting memories
—
The researchers didn’t stop there, but tried to verify whether this degeneration could be slowed down. To do this they used matrix metalloproteinase (MMP) inhibitorsdrugs already under study in oncology and rheumatology, which block the enzymes responsible for the degradation of the extracellular matrix, including that of the perineuronal networks.
The result was surprising: Alzheimer’s mice treated with these drugs showed less destruction of the perineuronal networksmaintained a more intact social memory and they continued to recognize the other miceunlike subjects not treated with drugs. “Basically if we protect these neuronal structures already in the initial stagessocial memory remains intact much longer,” underlined researcher Lata Chaunsali.
The journey is still long
—
While on the one hand this is excellent news, on the other it is important to point out that we are only at the beginning. The study is still in the experimental phase and they will be needed further safety studies before these drugs can even be tested in humans. The premises, however, are very encouraging: “It is exciting to find a structural change that explains a specific type of memory loss in Alzheimer’s. And it is even more promising to know that we already have potentially usable drugs“, concluded Sontheimer.
© ALL RIGHTS RESERVED