Use of 31P NMR spectroscopy of whole heart energetics for detection of drug-induced cardiotoxicity
Disclosed are methods of determining cardiac toxicity of a compound of interest, wherein a heart or cardiac cell of a mammal may be contacted a compound of interest and peak levels of one or more indicators of cardiac energetics after administration of the compound may be detected using 31 P NMR before and after exposure to a compound known to stress the heart or cardiac cell. Detection of the indicators of cardiac energetics may be combined with other indicators of cardiac function such as, for example, contractility, relaxation, heart rate, and/or conduction velocity to arrive at a profile capable of predicting the cardiotoxicity of potential therapeutics.
1. A method of determining cardiac toxicity of a compound of interest, comprising the steps of
a. optionally, i) determining from a heart or cardiac cell of a mammal peak levels of one or more indicators of cardiac energetics selected from inorganic phosphate, phosphocreatine, ATPγ, or a combination thereof; and ii) one or more indicators of cardiac function selected from contractility, relaxation, heart rate, conduction velocity, or a combination thereof, before administration of said compound of interest to the heart or cardiac cell;
b. contacting said heart or cardiac cell of a mammal with said compound of interest;
c. measuring after step (b), i) peak levels of said one or more indicators of cardiac energetics after administration of said compound of interest to the heart or cardiac cell of the mammal; and, optionally, ii) one or more indicators of cardiac function selected from contractility, relaxation, heart rate, conduction velocity, or a combination thereof;
d. contacting said heart or cardiac cell of said mammal previously contacted with said compound of interest, after step (c) with an agent known to cause an increase in cardiac function, said cardiac function selected from contractility, relaxation, heart rate, conduction velocity, or a combination thereof;
e. measuring after step (d), i) peak levels of said one or more indicators of cardiac energetics after administration of said agent known to cause an increase in cardiac function; and, optionally ii) one or more indicators of cardiac function selected from contractility, relaxation, heart rate, conduction velocity, or a combination thereof;
f. comparing the levels of said one or more indicators obtained in step (c) with the levels of said one or more indicators obtained in step (e);
wherein a decrease in one or more indicators of cardiac energetics as measured in step (c) as compared to step (e) indicates that the compound of interest does, or is likely to have, cardiotoxic properties; and
wherein levels of said one or more indicators of cardiac energetics are obtained using 31P NMR.
2. The method of claim 1 , wherein a decrease in phosphocreatine and ATPγ indicates that said compound of interest is cardiotoxic.
3. The method of claim 1 , wherein said agent known to cause an increase in cardiac function comprises a beta adrenergic agonist.
4. The method of claim 1 , wherein steps (b) and (d) further comprise the step of measuring a biomarker known to be associated with cardiotoxicity.
5. The method of claim 4 , wherein said biomarker comprises TNFα.
6. The method of claim 1 , wherein the period of time between step (b) and step (d) is at least 5 minutes.
7. The method of claim 1 , wherein the period of time between step (b) and step (d) is at least 10 minutes.
8. The method of claim 1 , wherein the period of time between step (b) and step (d) is at least 20 minutes.
9. The method of claim 1 , wherein the period of time between step (b) and step (d) is at least 30 minutes.
10. The method of claim 1 , wherein the period of time between step (b) and step (d) is at least 45 minutes.
11. The method of claim 1 , wherein the period of time between step (b) and step (d) is at least one hour.