Diabetes is one of the
leading causes of deaths across the world. It
is a disease characterized by the presence of excess sugar in urine as well as
blood. In 17th century the disease was referred as "pissing evil".
heart attack, diabetes is the fastest growing disease affecting millions of
people across the world.
A study conducted at
the University of Iowa suggests that the over-activation of an important heart
enzyme causes the death of pacemaker cells of the heart and results in abnormal
heart rhythm and raised chances of sudden death in diabetic mice.
Mark Anderson, M.D.,
Ph.D., UI professor, chair, and department executive officer of internal
medicine, and the senior author of the study published in the Journal of
Clinical Investigation, stated, "Many studies have shown that patients
with diabetes are at especially high risk for dying from a myocardial
infarction (heart attack). Our study provides new evidence that this excess mortality
could involve a pathway where oxidized CaMKII enzyme plays a central
More than 8 percent of
the people of the United States are affected by diabetes. Reactive oxidative
stress (ROS) level is raised by diabetes and results in cellular damage.
Anderson's lab in 2008
revealed that oxidation showed CaMKII (calcium/calmodulin-dependent protein
Ca2+/calmodulin-dependent protein kinases II or CaM kinases II are
serine/threonine-specific protein kinases which are regulated by the Ca2+/calmodulin
Studies have linked
oxidative stress occurring due to diabetes to raised chances of death after a
heart attack via oxidation-based activation of the CaMKII enzyme.
Min Luo, D.O., Ph.D.,
a cardiology fellow in the UI Department of Internal Medicine and the lead
author, said, "Our findings suggest that oxidized CaMKII may be a
'diabetic factor' that is responsible for the increased risk of death among
patients with diabetes following a heart attack."
Min Luo and her team
assessed the relationship between diabetes and risk of death from heart attack
in a mouse model.
The scientists noted a
decrease in heart rates in diabetic mice and like human beings, the mice
doubled the risk of death occurring after a heart attack.
The facts from the diabetic
mice suggested that the deaths occurring as a result of heart attack were due
to abnormalities in heart rhythm. This encouraged the researchers to
investigate the pacemaker cells controlling the heart rate.
The experts discovered
high levels of oxidized CaMKII enzyme in the pacemaker cells of the heart.
When experts inhibited
oxidation-based activation of the enzyme less pacemaker cells died and normal
heart rates were noted in diabetic mice.
The study suggested
that by reducing the activation of the CaMKII enzyme in specific heart cells
can lower the risk of death occurring in heart patients with diabetes.
The research was financially supported by grant
from the National Heart, Lung and Blood Institute and from the Fondation