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Myocardial manganese elevation and proton relaxivity enhancement with manganese dipyridoxyl diphosphate. Ex vivo assessments in normally perfused and ischemic guinea pig hearts
Author(s) -
Brurok Heidi,
Skoglund Trine,
Berg Kirsti,
Skarra Sissel,
Karlsson Jan O. G.,
Jynge Per
Publication year - 1999
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/(sici)1099-1492(199910)12:6<364::aid-nbm585>3.0.co;2-z
Subject(s) - perfusion , ex vivo , manganese , in vivo , chemistry , guinea pig , coronary circulation , medicine , ischemia , coronary flow reserve , cardiology , blood flow , pathology , biochemistry , biology , in vitro , microbiology and biotechnology , organic chemistry
Manganese (Mn) dipyridoxyl diphosphate (MnDPDP) is the active component of a contrast medium for liver MRI. By being metabolized, MnDPDP releases Mn 2+ , which is taken up and retained in hepatocytes. The study examined whether MnDPDP elevates Mn content and enhances proton relaxivity in normal myocardium, but not in ischemic myocardium with reduced coronary flow and impaired metabolism. Isolated guinea pig hearts were perfused at normal flow or low flow, inducing global subtotal ischemia. Ventricular ATP and Mn contents, T 1 and T 2 were measured. At normal flow tissue Mn content increased from the control level of 4.1 to 70.4 µmol/100g dry wt with MnDPDP (3000 µ M ), while low‐flow perfusion with MnDPDP (3000 µ M ) resulted in a Mn content of 16.6 µmol/100 g dry wt. Prolonged ischemia (35 and 90 min) reduced tissue Mn down to the control level. T 1 shortening closely paralleled myocardial Mn elevations during both normal and low‐flow perfusion. The use of a Mn 2+ ‐releasing contrast agent like MnDPDP may be a promising principle in MRI assessments of myocardial function and viability in coronary heart disease by revealing a differential pattern of changes in T 1 relative to coronary flow, cell Mn uptake and retention, ion channel function and metabolism. Copyright © 1999 John Wiley & Sons, Ltd. Abbreviations used: MnDPDP manganese dipyridoxyl diphosphateKHBB Krebs–Henseleit bicarbonate bufferLV left ventricleLVP Left ventricular pressureLVDP LV developed (systolic − diastolic) pressureHR heart rateAoP aortic pressurePCr phosphocreatine