Intra-renal microcirculatory alterations on non-traumatic hemorrhagic shock induced acute kidney injury in pigs.

Acute kidney injury (AKI) is frequently seen in patients with hemorrhagic shock due to hypotension, tissue hypoxia, and inflammation despite adequate resuscitation. There is a lack of information concerning the alteration of renal microcirculation and perfusion during shock and resuscitation. The aim of this study was to investigate the possible role of renal microcirculatory alterations on development of renal dysfunction in a pig model of non-traumatic hemorrhagic shock (HS) induced AKI.Fully instrumented female pigs were divided into the two groups as Control (n = 6) and HS (n = 11). HS was achieved by withdrawing blood until mean arterial pressure (MAP) reached around 50 mmHg. After an hour cessation period, fluid resuscitation with balanced crystalloid was started for the duration of 1 h. The systemic and renal hemodynamics, renal microcirculatory perfusion (contrast-enhanced ultrasound (CEUS)) and the sublingual microcirculation were measured.CEUS peak enhancement was significantly increased in HS during shock, early-, and late resuscitation indicating perfusion defects in the renal cortex (p < 0.05 vs. baseline, BL) despite a stable renal blood flow (RBF) and urine output. Following normalization of systemic hemodynamics, we observed persistent hypoxia (high lactate) and high red blood cell (RBC) velocity just after initiation of resuscitation resulting in further endothelial and renal damage as shown by increased plasma sialic acid (p < 0.05 vs. BL) and NGAL levels. We also showed that total vessel density (TVD) and functional capillary density (FCD) were depleted during resuscitation (p < 0.05).In this study, we showed that the correction of systemic hemodynamic variables may not be accompanied with the improvement of renal cortical perfusion, intra-renal blood volume and renal damage following fluid resuscitation. We suggest that the measurement of renal injury biomarkers, systemic and renal microcirculation can be used for guiding to the optimization of fluid therapies.

Effect of Xenon Anesthesia Compared to Sevoflurane and Total Intravenous Anesthesia for Coronary Artery Bypass Graft Surgery on Postoperative Cardiac Troponin Release: An International, Multicenter, Phase 3, Single-blinded, Randomized Noninferiority Trial.

BACKGROUND: Ischemic myocardial damage accompanying coronary artery bypass graft surgery remains a clinical challenge. We investigated whether xenon anesthesia could limit myocardial damage in coronary artery bypass graft surgery patients, as has been reported for animal ischemia models. METHODS: In 17 university hospitals in France, Germany, Italy, and The Netherlands, low-risk elective, on-pump coronary artery bypass graft surgery patients were randomized to receive xenon, sevoflurane, or propofol-based total intravenous anesthesia for anesthesia maintenance. The primary outcome was the cardiac troponin I concentration in the blood 24 h postsurgery. The noninferiority margin for the mean difference in cardiac troponin I release between the xenon and sevoflurane groups was less than 0.15 ng/ml. Secondary outcomes were the safety and feasibility of xenon anesthesia. RESULTS: The first patient included at each center received xenon anesthesia for practical reasons. For all other patients, anesthesia maintenance was randomized (intention-to-treat: n = 492; per-protocol/without major protocol deviation: n = 446). Median 24-h postoperative cardiac troponin I concentrations (ng/ml [interquartile range]) were 1.14 [0.76 to 2.10] with xenon, 1.30 [0.78 to 2.67] with sevoflurane, and 1.48 [0.94 to 2.78] with total intravenous anesthesia [per-protocol]). The mean difference in cardiac troponin I release between xenon and sevoflurane was -0.09 ng/ml (95% CI, -0.30 to 0.11; per-protocol: P = 0.02). Postoperative cardiac troponin I release was significantly less with xenon than with total intravenous anesthesia (intention-to-treat: P = 0.05; per-protocol: P = 0.02). Perioperative variables and postoperative outcomes were comparable across all groups, with no safety concerns. CONCLUSIONS: In postoperative cardiac troponin I release, xenon was noninferior to sevoflurane in low-risk, on-pump coronary artery bypass graft surgery patients. Only with xenon was cardiac troponin I release less than with total intravenous anesthesia. Xenon anesthesia appeared safe and feasible.

Validation of a pharmacological model for mitochondrial dysfunction in healthy subjects using simvastatin: A randomized placebo-controlled proof-of-pharmacology study.

Proof-of-pharmacology models to study compounds in healthy subjects offer multiple advantages. Simvastatin is known to induce mitochondrial dysfunction at least partly by depletion of co-enzyme Q10. The goal of this study was to evaluate a model of simvastatin-induced mitochondrial dysfunction in healthy subjects and to determine whether mitochondrial dysfunction could be pharmacologically reversed by treatment with co-enzyme Q10 (ubiquinol). Subjects received simvastatin 40mg/day for 8 weeks. After 4 weeks, subjects were randomized to receive ubiquinol 300mg/day or placebo in a double-blinded fashion. Mitochondrial function was assessed by measuring the phosphocreatine recovery time (τ-PCr) using phosphorous Magnetic Resonance Spectroscopy (31P-MRS) after in-magnet exercise. After 4 weeks of simvastatin treatment, τ-PCr prolonged with 15.2% compared to baseline, (95%CI, 2.5-29.4%; P = 0.018, Fig. 3). After 8 weeks, τ-PCr further prolonged to 37.27s in the placebo group (prolongation of 18.5% compared to baseline, still significantly prolonged, 95%CI, 1.1-38.9%; P = 0.037), but shortened to 33.81s in the ubiquinol group (prolongation of 9.1% compared to baseline, no longer significantly prolonged, 95%CI, -7.9 to 29.2%; P = 0.31). At 8 weeks, there was no significant difference between groups (difference of 8.2%, 95%CI, -14.5 to 37.0%; P = 0.51). Simvastatin induces subclinical mitochondrial dysfunction in healthy subjects, which can be partly reversed by treatment with ubiquinol. This model of pharmacologically induced and reversed mitochondrial dysfunction can be used to study the effects of compounds that enhance mitochondrial function in healthy subjects.