AIMS AND METHODS: Recently it was suggested that ischaemic preconditioning (IP) protects the myocardium in a graded pattern as assessed by myocardial infarct size estimation. Using tissue biopsies we investigated the impact of the proposed graded pattern of protection on myocardial energy state in an open-chest porcine model of IP with either one (1xIP) or four (4xIP) episodes of preconditioning. Furthermore, we evaluated the relationship between interstitial energy-related metabolite levels obtained by the microdialysis technique and the degree of subsequent ischaemic insult. RESULTS: During the long ischaemia the difference between pre-ischaemic and post-ischaemic total adenylate pools and the sum of adenylate breakdown products (adenosine, inosine and hypoxanthine) as well as tissue lactate levels appeared as follows: non-IP > 1xIP > 4xIP (P < 0.05). Moreover interstitial peak levels of lactate, hypoxanthine and taurine displayed a graded pattern analogous to the development of ischaemic damage, where non-IP > 1xIP > 4xIP. CONCLUSIONS: We present for the first time concordant energy metabolic and morphometric data in support of IP being a stepwise phenomenon for protection of the ischaemic myocardium. Furthermore, IP resulted in proportionally higher levels of hypoxanthine (relative to inosine) in the ischaemic myocardium, suggesting a different handling of adenine nucleotide breakdown products in the IP myocardium.
AIMS AND METHODS: Recently it was suggested that ischaemic preconditioning (IP) protects the myocardium in a graded pattern as assessed by myocardial infarct size estimation. Using tissue biopsies we investigated the impact of the proposed graded pattern of protection on myocardial energy state in an open-chest porcine model of IP with either one (1xIP) or four (4xIP) episodes of preconditioning. Furthermore, we evaluated the relationship between interstitial energy-related metabolite levels obtained by the microdialysis technique and the degree of subsequent ischaemic insult. RESULTS: During the long ischaemia the difference between pre-ischaemic and post-ischaemic total adenylate pools and the sum of adenylate breakdown products (adenosine, inosine and hypoxanthine) as well as tissue lactate levels appeared as follows: non-IP > 1xIP > 4xIP (P < 0.05). Moreover interstitial peak levels of lactate, hypoxanthine and taurine displayed a graded pattern analogous to the development of ischaemic damage, where non-IP > 1xIP > 4xIP. CONCLUSIONS: We present for the first time concordant energy metabolic and morphometric data in support of IP being a stepwise phenomenon for protection of the ischaemic myocardium. Furthermore, IP resulted in proportionally higher levels of hypoxanthine (relative to inosine) in the ischaemic myocardium, suggesting a different handling of adenine nucleotide breakdown products in the IP myocardium.
Authors: Håkon Haugaa; Hernando Gómez; Donald R Maberry; Andre Holder; Olufunmilayo Ogundele; Ana Maria B Quintero; Daniel Escobar; Tor Inge Tønnessen; Hannah Airgood; Cameron Dezfulian; Elizabeth Kenny; Sruti Shiva; Brian Zuckerbraun; Michael R Pinsky Journal: Crit Care Date: 2015-04-22 Impact factor: 9.097
Authors: Kristina Svennerholm; Pouria Rodsand; Urban Hellman; Anders Waldenström; Marie Lundholm; Dag Ahrén; Björn Biber; Gunnar Ronquist; Michael Haney Journal: PLoS One Date: 2016-07-19 Impact factor: 3.240
Authors: Kristina Svennerholm; Pouria Rodsand; Urban Hellman; Marie Lundholm; Anders Waldenström; Björn Biber; Gunnar Ronquist; Michael Haney Journal: Int J Cardiol Heart Vasc Date: 2015-05-23