Researchers have discovered a protein that is responsible for regulating the heart’s electrical activity and could help explain why so many instances of cardiac arrest or sudden cardiac death (SCD) occur in the morning. Dr. Mukesh Jain, director of the Case Cardiovascular Research Institute at Case Western Reserve University in Cleveland, Ohio, and his colleagues discovered that KLF15 occurs in the body in levels that rise and fall at certain fixed points throughout the day. The protein helps create channels that allow substances to enter and exit heart cells in ways critical to maintaining a normal, steady heartbeat, they explained. Dr. Jain’s team discovered that patients with heart failure have lower KLF15 levels, as established in laboratory mice that it substance links SCD with the body’s circadian rhythm. Their discovery provides evidence supporting the possible existence of a molecular link between SCD/cardiac arrest and that internal clock, Dr. Jain said Sunday during the 246th National Meeting & Exposition of the American Chemical Society (ACS) in Indianapolis, Indiana. The researchers located a previously undetected factor in the processes which cause the heart’s main pumping chambers to suddenly begin beating erratically, halting the flow of blood to a person’s brain and body. This condition, which is known as ventricular fibrillation, triggers SCD, which causes a patient to become instantly unconscious and potentially die unless CPR or a defibrillator is able to restore the heart’s normal, steady beat. “Sudden cardiac death due to this electrical instability causes an estimated 325,000 deaths annually in the United States alone,” explained Dr. Jain. “That includes the 3 out of 4 heart disease deaths in people aged 35-44. In all too many cases, there is no second chance. The first event is the last event. Our research points the way toward possible ways of easing that toll – new drugs that could reduce that risk, for example.” For more than three decades, health experts have known that these erratic heartbeats typically strike at specific times throughout the day. The peak hours for this phenomenon occur between 6am and 10am, and a second, smaller peak occurs during the late afternoon hours, the researchers said. Scientists had long suspected that there was a link between SCD and the body’s circadian clock, which is located in the brain and controls sleep cycles. As a result of their research, they discovered that mice with low KLF15 levels often have the same heart conditions as humans with SCD, and that individuals with low levels of the protein are the ones most susceptible to early-morning episodes of sudden cardiac death, Dr. Jain said. “So, we think that if we could in some way boost KLF15 levels in patients with heart problems, maybe we can reduce the occurrence of these arrhythmias and SCD,” he continued, noting that the protein is also involved in other body processes. “If we can find out how these compounds are boosting KLF15 levels, then maybe we can make much more targeted and specific therapies for the heart that would prevent SCD, but leave the other KLF15-related processes alone.” Source
