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own department, especially since there are increasing possibilities to generate them from

adult cells, especially the old cells of the patient and the patient (ethically safer method,

but more difficult). But this is still a long way off. Therefore, let us now look at the further

effects of the beta-blocker on gene expression, because these can already be given (just as,

for example, the lowering of blood pressure by ACE inhibitors, which even now has a

favourable effect on life expectancy). The beta blocker, amazingly, changes numerous

other genes in expression, namely because the signaling cascade is now downregulated

and this downregulates many genes as well as upregulating some others. Even stronger

(and a little slower in its effect) is the heart-protective effect: genes for the further growth

of the heart are somewhat down-regulated by the heart failure. However, some genes are

transcribed more strongly again.

Finally, there is another factor when giving a drug (a pharmacon): very often these

drugs hit the intended receptor, but more or less fit other receptors as well. The resulting

gene expression changes are the side effects. Applied to our example, it is particularly the

case that there are beta receptors not only in the heart, but also in many other organs, for

example in the lungs. Although there are slightly different beta receptors there, namely

beta2 receptors as opposed to beta1 receptors of the heart. Still, the risk of getting a bad

side effect in the lungs this way is high enough that people try not to give beta blockers in

9  Complex Systems Behave Fundamentally in a Similar Way