Research Roundup: A Deeper Understanding of Alzheimer’s
Every week there are numerous scientific studies published. Here’s a look at some of the more interesting ones.
Understanding the Mechanism of Decreased Blood Flow to the Brain in Alzheimer’s
It is well understood that there is decreased blood flow to the brain in Alzheimer’s patients. However, why that happens was not well understood. However, a research group with the University College London found that it may be caused when cells that are wrapped around blood vessels contract, which can decrease blood supply by half.
The cells involved are pericytes, which are wrapped around capillaries and have the ability to contract and regulate blood flow. Looking at the capillaries in Alzheimer’s affected human brain tissue and in mice bred to develop Alzheimer’s, they found the capillaries were being squeezed by pericytes. And when they applied amyloid-beta, a protein that accumulates in the brains of Alzheimer’s patients, to the healthy brain tissue, the capillaries were squeezed.
“Our study has, for the first time, identified the underlying mechanisms behind the reduction of brain blood flow in Alzheimer’s disease,” stated lead author Ross Nortley. “Since reduced blood flow is the first clinically detectable sign of Alzheimer’s, our research generates new leads for possible treatments in the early phase of the disease.”
• Cannabinoid as an Antibiotic?
Cannabinoid is the primary non-psychoactive chemical in cannabis and hemp. It has been approved by the U.S. Food and Drug Administration (FDA) for a form of epilepsy and is being studied for a number of other medical conditions. Researchers found that it is active against Gram-positive bacteria, including the ones behind Staphylococcus aureus and Streptococcus pneumoniae, with potency similar to the antibiotics vancomycin or daptomycin.
• Swimming in the Ocean Alters Skin Microbiome
Research into the microbiome—the trillions of bacteria, viruses and fungi that live in and on the body—is intensifying, finding it plays a significant role in a broad variety of diseases, not just gastrointestinal illnesses. Researchers recently found that swimming in the ocean changes the skin microbiome and likely increases susceptibility to infection. The ocean water appears to wash away normal skin microbiome and replace it with ocean bacteria.
• Why Checkpoint Inhibitors Sometimes Don’t Work
Researchers at the University of Colorado Cancer Center published research in the journal Cancer Immunology Research that provides deeper insight into why sometimes checkpoint inhibitors don’t work. Tumors have a surface protein called PD-L1. T-cells, a type of immune cell, have a surface protein called PD1. Tumor cells use PD-L1 to essentially trigger PD1 to tell T-cells to leave them alone. Checkpoint inhibitors act by blocking the function of either PD-L1 (Keytruda, for example) or PD1 (Bristol-Myers Squibb’s Opdivo).
Another group of proteins is called the major histocompatibility complex (MHC). MHC proteins transport antigens from inside a cell and move them to the cell surface so they can be “seen” by T-cells. And when T-cells recognize a dangerous antigen on an MHC protein, they attack the cell—unless the T-cell is deactivated by the PD1/PD-L1 interaction. However, if a cancer cell doesn’t have MHC proteins, there’s no PD1/PD-L1 interaction because the cancer cell isn’t presenting any antigens for the immune system to see.
• Human Centromeres Preserve DNA from Neanderthals and Other Ancient Humans
The centromere anchors chromosomes when cells divide. When observed under a microscope, the centromere appears like a pinched part of the chromosome. However, centromeres do not participate much in crossover events that allow evolutionary activity. Researchers analyzed centromeric DNA and found that it contained material from Neanderthal DNA in non-African genomes as well as ancient African genomes.
• Even More Data Links Immune System Reaction to Alzheimer’s Disease
Increasingly, research is suggesting that although the accumulation of amyloid and tau proteins is involved in Alzheimer’s disease, it is actually an immune reaction to it that causes the brain tissue damage that results in memory loss and confusion. Researchers at Washington University School of Medicine in St. Louis have added to that theory, suggesting that these brain immune cells, microglia, appear to damage nearby cells when they aren’t working properly.