Failure to protect the myocardium against ischemia/reperfusion injury after chronic atorvastatin treatment is recaptured by acute atorvastatin treatment: a potential role for phosphatase and tensin homolog deleted on chromosome ten?
OBJECTIVE
We sought to ascertain whether chronic oral therapy with atorvastatin protects against ischemia/reperfusion (I/R) injury.


BACKGROUND
We have recently shown that acute atorvastatin treatment protects against reperfusion-induced injury by activating the PI3K/Akt/eNOS pathway. However, many patients are on chronic statin therapy, and it is necessary to investigate whether this, in itself, provides a therapeutic advantage.


METHODS
Sprague-Dawley rats were orally treated for one day, three days, one week, or two weeks with 20 mg/kg of atorvastatin or vehicle, after which the hearts underwent 35 min of ischemia and 120 min reperfusion (IR). Two additional groups were treated for one or two weeks with atorvastatin and then received a supplementary dose of 40 mg/kg before IR. The risk zone was determined using Evans blue and infarct size (IR%) using triphenyltetrazolium chloride staining.


RESULTS
Treatment with atorvastatin for one and three days significantly reduced infarct size versus controls (38.9 +/- 3.1% vs. 56.4 +/- 2.3%; 39.3 +/- 2.4% vs. 61.3 +/- 3.8%, respectively). However, after one or two weeks of treatment, no protection was observed (52.6 +/- 3.8% vs. 58.6 +/- 4.3%; 58.3 +/- 2.7% vs. 52.4 +/- 5.7%, respectively). Surprisingly, a supplementary dose of atorvastatin recaptured the protection in the groups treated chronically (36.2 +/- 2.8% vs. 58.6 +/- 4.3%; 26.8 +/- 1.5% vs. 51.2 +/- 6.7%, at one and two weeks, respectively). Interestingly, we observed an increased level of phosphatase and tensin homolog deleted on chromosome ten (PTEN), the phosphatidylinositol-3 kinase inhibitor, in the chronic treated hearts.


CONCLUSIONS
In conclusion, atorvastatin appears to have an acute protective effect that wanes with time associated with an increase in PTEN levels. This waning protection can be recaptured by an acute high dose given immediately before IR. These results may have protential clinical relevance.
Mensah
Kwabena
K
Hatter Institute and Centre for Cardiology, University College London Hospital and Medical School, London, United Kingdom.
Mocanu
Mihaela M
MM
Yellon
Derek M
DM
D000818:Animals; D000069059:Atorvastatin; D015153:Blotting, Western; D006538:Heptanoic Acids / Q000008:administration & dosage*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage*; D008297:Male; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011758:Pyrroles / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000517:prevention & control*; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000502:physiology*
D000069059:Atorvastatin; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases; D010744:Phosphoric Monoester Hydrolases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011758:Pyrroles; D025521:Tumor Suppressor Proteins; C494920:Akt1 protein, rat