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Rivista di Chirurgia Cardiaca, Vascolare e Toracica

Indexed/Abstracted in: BIOSIS Previews, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,632

Periodicità: Bimestrale

ISSN 0021-9509

Online ISSN 1827-191X


The Journal of Cardiovascular Surgery 1999 Agosto;40(4):481-6



Effects of ­heat ­stress on metab­olism of ­high-­energy phos­phates. Com­par­ison of nor­mo­thermic and hypo­thermic ­ischemia

Jayakumar J., Smolenski R. T., Gray C. C., Goodein A. T., Amrani M., Yacoub M. H.

From the Depart­ment of Car­di­oth­o­racic Sur­gery National ­Heart and ­Lung Insti­tute Imperial College School of Med­i­cine Hare­field Hos­pital, Hare­field, Mid­dlesex, UK

Back­ground. Alter­a­tions in meta­bolic path­ways may con­tribute to the car­di­op­ro­tec­tive ­effects of ­heat ­stress (HS). We inves­ti­gated the ­effects of HS on ATP and phos­pho­crea­tine (PCr) ­levels in the ­ischemic rat myo­car­dium, ­after ­both nor­mo­thermic and hypo­thermic ­ischemia.
­Methods. Two pro­to­cols ­were ­used: (1) nor­mo­thermic ­ischemia (20 min at 37°C) ­with no myo­car­dial pro­tec­tion (n=6 HS; n=6 con­trol); (2) hypo­thermic ­ischemia (4 hrs at 4°C) ­after car­di­o­plegic ­arrest (n=6 HS; n=6 con­trol). ATP and PCr ­levels in the ­heart ­were meas­ured ­using 31P ­nuclear mag­netic res­o­nance spec­tros­copy.
­Results. At the end of nor­mo­thermic ­ischemia, ATP ­levels ­were ­better main­tained in HS ­hearts (C vs HS: 4.51±0.66 vs 7.81±1.06 ­μmol/g dry wt±SEM, p=0.04). A ­trend for ­higher ATP con­tent in HS ­hearts was ­observed ­after 40 min of reper­fu­sion (C vs HS: 11.7±1.5 vs 16.9±2.0 ­μmol/g dry wt±SEM, p=0.09). PCr con­tent was ­also ­higher at the end of 40 min­utes of reper­fu­sion in HS ­hearts (C vs HS: 46.4±2.9 vs 56.9±3.0 ­μmol/g dry wt±SEM, p=0.03). ­After pro­longed hypo­thermic ­ischemia ­under car­di­o­plegic ­arrest, ­heat ­stress ­again led to ­better pres­er­va­tion of ATP ­levels at the end of ­ischemia (C vs HS: 5.71±0.88 vs 9.23±1.38 ­μmol/g dry ­wt±SEM, p=0.05) and ­after 40 min­utes of reper­fu­sion (C vs HS: 16.8±1.4 vs 24.6±2.8 ­μmol/g dry wt±SEM, p=0.03). PCr ­levels ­were ­also ­better main­tained at the end of ­ischemia (C vs HS: 4.87±0.77 vs 12.4±3.0 ­μmol/g dry wt±SEM, p=0.03) and ­after 40 min­utes of reper­fu­sion in HS ­hearts (C vs HS: 55.1±7.0 vs 79.8±7.3 ­μmol/g dry wt±SEM, p=0.03).
Con­clu­sions. ­Heat ­stress ­induces ­changes in the ­energy pro­file of the ­heart ­which ­results in ­better pres­er­va­tion of ATP and phos­pho­crea­tine ­levels. ­These ­changes ­could be ­observed ­after ­brief nor­mo­thermic ­ischemia and ­also ­after pro­longed hypo­thermic ­ischemia ­under car­di­o­plegic ­arrest, mim­icking con­di­tions of pres­er­va­tion for car­diac trans­plan­ta­tion.

lingua: Inglese


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