Effects of Bretschneider cardioplegic fluid on the lysosomal cathepsins D and L of myocardium of coronary patients during coronary-aortal bypass graft operation.
We evaluated the effects of replacing the standard St. Thomas Hospital (ST) cardioplegic fluid with Bretschneider (BR) fluid during coronary-aortal bypass graft operation (CABG) in patients with coronary disease. BR fluid contains enormous concentration of histidine (approximately 0.2 mole L-1): thus increased levels of histamine or other metabolites might exert some cardiovascular effects. Therefore, the changes in the level of two lysosomal proteases: cathepsin D and L of myocardium were evaluated. Small fragments of right atrium (SFRA) were taken out during CABG: just before the injection of cold cardioplegia (control), at the peak of ischaemia and after reperfusion. Cathepsin D and L were assayed in SFRA homogenates at pH 3.6 (with haemoglobin as a substrate and pepstatin as cathepsin D inhibitor). The values of parameters Ai and Ae: being the indexes of intralysosomal (Ai) and extralysosomal (Ae) activation or inactivation of cathepsins were calculated.


RESULTS
With BR cardioplegia--unlikely ST fluid--there is a significant increase in total activity (T) of both cathepsins but free (F) only for cathepsin L during ischaemia with come back (to the control level) during reperfusion period. T for both cathepsins and F for cathepsin L with BR are much greater than those with ST fluid both in ischaemia and reperfusion period. BR cardioplegia results in distinct, extralysosomal activation of cathepsin L during ischaemia instead of the inhibition found with ST fluid.
Turski
W A
WA
Department of Neurology and Oromandibular Dysfunction, Institute of Dentistry, Medical University, ul. Pomorska 251, 92-213 Łódź, Poland.
Zasłonka
J
J
D000328:Adult; D002314:Cardioplegic Solutions; D002402:Cathepsin D / Q000378:metabolism*; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000201:enzymology* / Q000601:surgery*; D003546:Cysteine Endopeptidases; D010450:Endopeptidases; D005260:Female; D005947:Glucose; D006801:Humans; D008247:Lysosomes / Q000201:enzymology; D008297:Male; D008353:Mannitol; D008875:Middle Aged; D009206:Myocardium / Q000201:enzymology*; D011189:Potassium Chloride; D011343:Procaine
C039984:Bretschneider cardioplegic solution; D002314:Cardioplegic Solutions; D008353:Mannitol; D011343:Procaine; D011189:Potassium Chloride; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; C534281:CTSL protein, human; D056668:Cathepsin L; D002402:Cathepsin D; D005947:Glucose