Speciality
Spotlight

 




           

Clinical Pharmacology

       

     





Myocardial Infarction

   

  • Leo
    Hofstra,
    Ing Han Liem et al




    Visualisation of cell death in vivo in patients
    with acute myocardial infarction




    Lancet, vol.356, July 15, 2000, pg. 209-212.


     

      


    In patients with acute myocardial infarction,
    cardiomyocyte death occurs in the infarct area. Animal studies have shown that ischemia of heart, followed by
    reperfusion, results in substantial loss of
    cardiomyocytes through apoptosis (programmed cell
    death). DNA
    fragmentation- a hallmark of apoptosis has been
    shown in cardiac biopsy samples obtained from
    patients with acute MI. An early event in apoptosis is
    externalization of phosphatidylserine from inner
    leaflet of plasma membrane to outer leaflet. The authors have shown that labelled annexin-V,
    which has a high affinity for phosphatidylserine is
    a specific and reliable tool for detection of
    apoptic cells- during ischemia and reperfusion in
    the murine heart. On the basis of these studies, authors have
    tested radionuclide imaging with
    technetium-99m-labelled human recombinant annexin-V
    to visualize cardiac cell death after reperfusion
    therapy in patients with an acute MI.

      

    Seven
    patients with an acute MI and 1 control were
    studied. All
    patients were treated with percutaneous transluminal
    coronary angioplasty. SPECT images of the heart were obtained after
    injecting I.V. 1mg of annexin V labelled with Tc-99m 2 hours after reperfusion. Routine myocardial resting-perfusion imaging
    was also done to verify infarct localisation.




      

    Interpretation
    of the study was that there was increased uptake of
    Tc-99m labelled annexin-V in the infarcted area of
    patients with an acute MI, suggesting that
    programmed cell death occurs in that area. This imaging technique may allow study of
    dynamics of reperfusion induced cell death in the
    area at risk and may help to assess interventions
    that inhibit cell death in patients with an acute
    MI.




      

    Editors’ comments :


     

     


    Radioimaging
    to identify myocardial cell death and probably
    injury.




     

    An
    imaging technique that identifies cell damage
    rapidly could facilitate clinical decision making. Although at least 3 hrs was required for
    radioannexin to be localised in Hofstra and
    colleagues’ study, improvement in
    radiopharmaceutical may permit more rapid imaging. Non-invasive targeting of apoptosis and
    stress induced externalisation of phosphatidylserine
    will lead to development of drugs and other
    treatments for increasing salvage of myocardium.

        



  
 



 

     

Speciality Spotlight

 

           
Clinical Pharmacology
       

     

Myocardial Infarction
   

  • Leo Hofstra, Ing Han Liem et al


    Visualisation of cell death in vivo in patients with acute myocardial infarction


    Lancet, vol.356, July 15, 2000, pg. 209-212.

     

      
    In patients with acute myocardial infarction, cardiomyocyte death occurs in the infarct area. Animal studies have shown that ischemia of heart, followed by reperfusion, results in substantial loss of cardiomyocytes through apoptosis (programmed cell death). DNA fragmentation- a hallmark of apoptosis has been shown in cardiac biopsy samples obtained from patients with acute MI. An early event in apoptosis is externalization of phosphatidylserine from inner leaflet of plasma membrane to outer leaflet. The authors have shown that labelled annexin-V, which has a high affinity for phosphatidylserine is a specific and reliable tool for detection of apoptic cells- during ischemia and reperfusion in the murine heart. On the basis of these studies, authors have tested radionuclide imaging with technetium-99m-labelled human recombinant annexin-V to visualize cardiac cell death after reperfusion therapy in patients with an acute MI.
      
    Seven patients with an acute MI and 1 control were studied. All patients were treated with percutaneous transluminal coronary angioplasty. SPECT images of the heart were obtained after injecting I.V. 1mg of annexin V labelled with Tc-99m 2 hours after reperfusion. Routine myocardial resting-perfusion imaging was also done to verify infarct localisation.


      
    Interpretation of the study was that there was increased uptake of Tc-99m labelled annexin-V in the infarcted area of patients with an acute MI, suggesting that programmed cell death occurs in that area. This imaging technique may allow study of dynamics of reperfusion induced cell death in the area at risk and may help to assess interventions that inhibit cell death in patients with an acute MI.


      
    Editors’ comments :

     

     
    Radioimaging to identify myocardial cell death and probably injury.


     
    An imaging technique that identifies cell damage rapidly could facilitate clinical decision making. Although at least 3 hrs was required for radioannexin to be localised in Hofstra and colleagues’ study, improvement in radiopharmaceutical may permit more rapid imaging. Non-invasive targeting of apoptosis and stress induced externalisation of phosphatidylserine will lead to development of drugs and other treatments for increasing salvage of myocardium.
        

    

 

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