Circulatory Health magazine

Did you know that the cells in our body have a 24-hour
rhythm? And that this internal clock influences such functions
as the regenerative ability of cells? Cardiologist Linda van
Laake studies this fact and all of its implications. "There are
indications that cardiac cells can handle a lack of oxygen
better in the afternoon than in the early morning."
Not only people, but also animals, plants and
individual cells in our body - even when they
are isolated on a Petri dish - appear to live by
this 24-hour rhythm. A greater understanding
of that rhythm could have a major impact for
the medical world.
Linda: "Heart cells appear to have a fixed
circadian rhythm. Simply speaking, you could
say that they are active during the day and
rest in the evening. This could mean that the
regenerative ability of cells, for instance after
surgery, could also vary depending on time."
Internal clock
There is a lot we don't know yet about this
'internal clock', but researchers suspect that
the body prefers to perform certain tasks, such
as repairing cells, at times that it does not have
to be on stand-by for sudden action, such as
running to catch a train. In some diseases, this
circadian rhythm becomes unbalanced. This
appears to be the case with heart failure, which
decreases the pump function of the heart, after
Heart failure is a
chronic disease,
gradually decreasing
the pump function of
the heart. Heart failure
is one of the four
research themes of the
strategic theme
Circulatory Health. By
doing research, we
want to improve the
detection, prognosis
and treatment of heart
failure.
a heart attack for example.
Linda: "We currently study whether heart failure
can be treated more effectively if you take the
phase of the heart cells into account. This also
provides an opportunity to solve a different
problem: "The 24-hour rhythm and the resulting
differences in cellular activity may explain why
heart failure cannot be cured yet with stem cells."
Stem cells are our body's primitive cells: they
can still develop into all kinds of cells, such
as blood, skin or heart cells. Scientists have
been trying for years to repair the piece of
heart muscle that has died after a heart attack
using these stem cells. But that appears to be
more difficult than we thought. "My focus is on
improving the heart muscle cells cultured from
stem cells using the 24-hour rhythm. In other
words: transplanting the cells when they are
in their 'optimal phase' in terms of therapeutic
properties. Or manipulating them to make this
optimal phase continuous."
Early days
While it is still early days for this research, the
results so far are promising. Linda emphasizes:
“It is important to realize that there are circadian
rhythms. If we can work them out and adjust
medical treatment to them, we stand to gain an
advantage."
Circulatory Health Magazine 39