@article{MagyarWagnerThomasetal.2019,
  author    = {Magyar, Attila and Wagner, Martin and Thomas, Phillip and Malsch, Carolin and Schneider, Reinhard and St{\"o}rk, Stefan and Heuschmann, Peter U and Leyh, Rainer G and Oezkur, Mehmet},
  title     = {HO-1 concentrations 24 hours after cardiac surgery are associated with the incidence of acute kidney injury: a prospective cohort study},
  series = {International Journal of Nephrology and Renovascular Disease},
  volume    = {12},
  journal   = {International Journal of Nephrology and Renovascular Disease},
  doi       = {10.2147/IJNRD.S165308},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177250},
  pages     = {9-18},
  year      = {2019},
  abstract  = {Background: Acute kidney injury (AKI) is a serious complication after cardiac surgery that is associated with increased mortality and morbidity. Heme oxygenase-1 (HO-1) is an enzyme synthesized in renal tubular cells as one of the most intense responses to oxidant stress linked with protective, anti-inflammatory properties. Yet, it is unknown if serum HO-1 induction following cardiac surgical procedure involving cardiopulmonary bypass (CPB) is associated with incidence and severity of AKI. Patients and methods: In the present study, we used data from a prospective cohort study of 150 adult cardiac surgical patients. HO-1 measurements were performed before, immediately after and 24 hours post-CPB. In univariate and multivariate analyses, the association between HO-1 and AKI was investigated. Results: AKI with an incidence of 23.3\% (35 patients) was not associated with an early elevation of HO-1 after CPB in all patients (P=0.88), whereas patients suffering from AKI developed a second burst of HO-1 24 hours after CBP. In patients without AKI, the HO-1 concentrations dropped to baseline values (P=0.031). Furthermore, early HO-1 induction was associated with CPB time (P=0.046), while the ones 24 hours later lost this association (P=0.219). Conclusion: The association of the second HO-1 burst 24 hours after CBP might help to distinguish between the causality of AKI in patients undergoing CBP, thus helping to adapt patient stratification and management.},
  language  = {en}
}
@article{LeistnerSommerKanofskyetal.2019,
  author    = {Leistner, Marcus and Sommer, Stefanie and Kanofsky, Peer and Leyh, Rainer and Sommer, Sebastian-Patrick},
  title     = {Ischemia time impacts on respiratory chain functions and Ca\(^{2+}\)-handling of cardiac subsarcolemmal mitochondria subjected to ischemia reperfusion injury},
  series = {Journal of Cardiothoracic Surgery},
  volume    = {14},
  journal   = {Journal of Cardiothoracic Surgery},
  doi       = {10.1186/s13019-019-0911-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236455},
  year      = {2019},
  abstract  = {Background Mitochondrial impairment can result from myocardial ischemia reperfusion injury (IR). Despite cardioplegic arrest, IR-associated cardiodepression is a major problem in heart surgery. We determined the effect of increasing ischemia time on the respiratory chain (RC) function, the inner membrane polarization and Ca\(^{2+}\) homeostasis of rat cardiac subsarcolemmal mitochondria (SSM). Methods Wistar rat hearts were divided into 4 groups of stop-flow induced warm global IR using a pressure-controlled Langendorff system: 0, 15, 30 and 40 min of ischemia with 30 min of reperfusion, respectively. Myocardial contractility was determined from left ventricular pressure records (dP/dt, dPmax) with an intraventricular balloon. Following reperfusion, SSM were isolated and analyzed regarding electron transport chain (ETC) coupling by polarography (Clark-Type electrode), membrane polarization (JC1 fluorescence) and Ca2+-handling in terms of Ca\(^{2+}\)-induced swelling and Ca\(^{2+}\)-uptake/release (Calcium Green-5 N® fluorescence). Results LV contractility and systolic pressure during reperfusion were impaired by increasing ischemic times. Ischemia reduced ETC oxygen consumption in IR40/30 compared to IR0/30 at complex I-V (8.1 ± 1.2 vs. 18.2 ± 2.0 nmol/min) and II-IV/V (16.4 ± 2.6/14.8 ± 2.3 vs. 2.3 ± 0.6 nmol/min) in state 3 respiration (p < 0.01). Relative membrane potential revealed a distinct hyperpolarization in IR30/30 and IR40/30 (171.5 ± 17.4\% and 170.9 ± 13.5\%) compared to IR0/30 (p < 0.01), wearing off swiftly after CCCP-induced uncoupling. Excess mitochondrial permeability transition pore (mPTP)-gated Ca\(^{2+}\)-induced swelling was recorded in all groups and was most pronounced in IR40/30. Pyruvate addition for mPTP blocking strongly reduced SSM swelling in IR40/30 (relative AUC, ± pyruvate; IR0/30: 1.00 vs. 0.61, IR15/30: 1.68 vs. 1.00, IR30/30: 1.42 vs. 0.75, IR40/30: 1.97 vs. 0.85; p < 0.01). Ca2+-uptake remained unaffected by previous IR. Though Ca\(^{2+}\)-release was delayed for ≥30 min of ischemia (p < 0.01), Ca\(^{2+}\) retention was highest in IR15/30 (RFU; IR0/30: 6.3 ± 3.6, IR 15/30 42.9 ± 5.0, IR30/30 15.9 ± 3.8, IR40/30 11.5 ± 6.6; p ≤ 0.01 for IR15/30 against all other groups). Conclusions Ischemia prolongation in IR injury gradually impaired SSM in terms of respiratory chain function and Ca\(^{2+}\)-homeostasis. Membrane hyperpolarization appears to be responsible for impaired Ca2+-cycling and ETC function. Ischemia time should be considered an important factor influencing IR experimental data on subsarcolemmal mitochondria. Periods of warm global ischemia should be minimized during cardiac surgery to avoid excessive damage to SSMs.},
  language  = {en}
}