The researchers found that by removing brain immune cells known as microglia from rodent models of Alzheimer’s disease, beta-amyloid plaques the hallmark pathology of AD never formed. Their study will appear Aug. 21 in the journal Nature Communications. Previous research has shows most Alzheimer’s risk genes are turne on in microglia; suggesting these cells play a role in the disease. Therefore “However, we hadn’t understood exactly what the microglia are doing and whether they are significant in the initial Alzheimer’s process,” said Kim Green, associate professor of neurobiology & behavior.
Removing brain immune cells
“They decided to examine this issue by looking at what would happen in their absence.” The researchers used a drug that blocks microglia signaling that is necessary for their survival. Green and his lab have previously shown that blocking this signaling effectively eliminates these immune cells from the brain. “What was striking about these studies is we find that in areas without microglia, plaques didn’t form;” Green said. “However, in places where microglia survived, plaques did develop. You don’t have Alzheimer’s without plaques; and we now know microglia are a necessary component in the development of Alzheimer’s.”
The scientists also discovered that when plaques are present, microglia perceive them as harmful and attack them. However, the attack also switches off genes in neurons needed for normal brain functioning. “This finding underlines the crucial role of these brain immune cells in the development and progression of Alzheimer’s;” said Green. Professor Green and colleagues say their discovery holds promise for creating future drugs that prevent the disease. “They are not proposing to remove all microglia from the brain,” Professor Green said, noting the importance of microglia in regulating other brain functions.
Affect microglia in targeted
“What could be possible is devising therapeutics that affect microglia in targeted ways.” He also believes the project’s research approach offers an avenue for better understanding other brain disorders. the immune system defending the body against both infectious disease and foreign materials. But Five different and diverse types of leukocytes exist; but they are all produced and derived from a multi potent cell in the bone marrow known as a hematopoietic stem cell.
Leukocytes are found throughout the body; including the blood and lymphatic system. The number of leukocytes in the blood is often an indicator of disease. There are normally between 4×109 and 1.1×1010 white blood cells in a litre of blood, making up approximately 1% of blood in a healthy adult. An increase in the number of leukocytes over the upper limits is called leukocytosis, and in leukopenia; this number is much lower than the lower limit.