Atrial Fibrillation - Genetics and Root Causes
Getting to the heart of the matter...
Genetic Lifehacks
Hi there,
My latest article is about atrial fibrillation (AFib), a type of irregular heartbeat.
The role of genetic variants has been known for more than a decade, but just knowing the (common) genetic variants that increase susceptibility didn't explain why AFib happens to some people and not to others.
Several recent studies have helped to clarify what happens in heart muscle tissue to cause the changes that initiate AFib and keep it going.
Research shows that a lack of resolution of inflammation causes changes in heart tissue that then combine with genetic susceptibility to cause AFib. Yes, the lack of resolution of inflammation is at the heart of so many chronic diseases.
This article was one that I started several years ago at a member's request, but it had languished as a draft because I felt that it was missing something big -- the "why". Genetic variants clearly increase susceptibility to atrial fibrillation, but I was missing what pushes someone over the edge into arrhythmia and keeps them there.
Why am I sharing this? First, I do appreciate all suggestions for article topics, but it sometimes takes a while for an article to come together. Second, it's a good reminder that the research on health issues is getting better all the time, and we all need to keep digging to understand the root cause.
With gratitude, Debbie
Atrial fibrillation: Intersection of genetic susceptibility with inflammation and remodeling
Key takeaways:
~ Atrial fibrillation is an irregular heartbeat in which the upper chambers of the heart to have an irregular rhythm.
~ Structural changes in the heart muscle or changes in ion channels can increase the risk of atrial fibrillation.
~ Failure to resolve inflammation can lead to changes in heart tissue that make it susceptible to atrial fibrillation.
~ Genetic variants are strongly associated with an increased risk of AFib, especially when combined with inflammation or a triggering event.
In case you want to learn more about the resolution of inflammation...
Specialized Pro-resolving Mediators (SPMs): The Resolution of Inflammation
Key takeaways:
~ The resolution of inflammation is an active process.
~ Specialized pro-resolving lipid mediators (SPMs) are key to triggering the resolution of inflammation.
~ These pro-resolving mediators are synthesized from DHA and EPA (omega-3 fatty acids).
~ A lack of pro-resolving mediators can allow inflammation to continue, leading to many chronic diseases.
~ Genetic comes into play with genes related to omega-3 fatty acids as well as the enzymes needed for synthesizing SPMs.
What I've been reading:
1) Resolvin T4 enhances macrophage cholesterol efflux to reduce vascular disease
Resolvins are specialized pro-resolving mediators, derived from DHA and EPA (omega-3s). This study showed that giving resolvins to mice with inflammatory arthritis (model of chronic inflammation) reduced atherosclerosis.
Related article: Specialized Pro-resolving Mediators and resolution of inflammation
2) Why autoimmune disease is more common in women: X chromosome holds clues
The Nature article explains new research on how the link between women having more autoimmune diseases may not be due to estrogen. Instead, it may be due to the way that the second X chromosome is inactivated. The process of inactivating the second X involves the XIST long-coding RNA, which is thought to prompt the formation of autoantibodies.
3) Blood pressure pulsations modulate central neuronal activity via mechanosensitive ion channel
This animal study attempts to answer the questions surrounding slow oscillation in brain waves in the olfactory bulb in mice. The findings were really interesting. The researchers found that there are mechanosensitive ion channels in a subset of neurons in the brain that directly sense blood pressure pulses from the heartbeat. From the study: "Although currently the function of this immediate pathway is a matter of speculation, we propose that a brain-wide network of “heartbeat sentinel neurons” mediates interoceptive modulation of cognition, mood, and autonomic status. For example, the occurrence of certain states of arousal might correlate with activation of this network. Our finding adds a fast transmission line to the interoceptive body-brain axis, whereby central neurons can feel the pulse within the brain."