New York: Looking at the molecular mechanisms behind tinnitus, a condition induced by exposure to loud noise that causes whistling, clicking, roaring and other phantom sounds, researchers have found a possible drug therapy for this chronic and sometimes debilitating condition. The study results build on previous research in mouse models demonstrating that tinnitus is associated with hyperactivity of dorsal cochlear nucleus (DCN) cells, which fire impulses even when there is no actual sound to perceive.
The team’s work showed that this hyperactivity is caused by a reduction in tiny channels, called KCNQ channels, through which potassium ions travel in and out of the cell.
Based on this finding, KCNQ channel activators have emerged as clinical candidates for preventing the development of tinnitus.
“However, a significant percentage of people are exposed to loud sounds and never develop tinnitus, and there was little known about why that is. That is what we set out to examine in this study,” said one of the researchers Thanos Tzounopoulos, associate professor at University of Pittsburgh School of Medicine.
The research was conducted on mice. The researchers found that resilience to tinnitus was linked to reduced activity of KCNQ channel.
The investigators believe a combination of drugs that enhance KCNQ channel activity and reduce activity of another called hyperpolarisation-activated cyclic nucleotide-gated (HCN) channel could promote resilience and reduce susceptibility to tinnitus.
Foetal cells affect mother’s health after pregnancyThese foetal cells which can persist in maternal tissues for decades after a child is born — have been associated with both protection and increased susceptibility to a range of afflictions, including cancer and autoimmune diseases like rheumatoid arthritis, the study said.
“Foetal cells can act as stem cells and develop into epithelial cells, specialised heart cells, liver cells and so forth,” said study lead author Amy Boddy, researcher at Arizona State University in the US.
“This shows they are very dynamic and play a huge role in the maternal body. They can even migrate to the brain and differentiate into neurons,” Boddy said.
The presence of foetal cells in maternal tissue is known as fetal microchimerism.
The researchers reviewed the available literature on foetal microchimerism and human health, and found that foetal cells enter a cooperative relationship in some maternal tissues, compete for resources in other tissues and may exist as neutral entities –hitchhikers simply along for the ride.
It is likely that foetal cells play each of these roles at various times, the study said.
For example, foetal cells may contribute to inflammatory responses and autoimmunity in the mother, when they are recognised as foreign entities by the maternal immune system.
This may account in part for higher rates of autoimmunity in women.
Foetal cells can also provide benefits to mothers, migrating to damaged tissue and repairing it.
In other cases, foetal cells from the placenta are swept through the bloodstream into areas including the lung, where they may persist merely as bystanders.