1
|
Serum markers for early detection of patients with mesenteric ischemia after cardiac surgery. Innov Surg Sci 2018; 3:277-283. [PMID: 31579792 PMCID: PMC6604586 DOI: 10.1515/iss-2018-0035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 11/15/2018] [Indexed: 12/12/2022] Open
Abstract
Objective Mesenteric ischemia (MESI) is a rare but often fatal complication in patients after cardiac surgery. Non-specific clinical symptoms and lack of specific laboratory parameters complicate the diagnosis. We evaluated potential serum markers for MESI in cardiac surgery patients. Methods Between March and October 2012, serial serum samples of 567 elective cardiac surgery patients were collected 1, 24, and 48 h after the operation, and concentrations of potential markers for MESI [α-glutathione-S-transferase (αGST), intestinal fatty-acid-binding protein (iFABP), and D-lactate] were measured retrospectively. In patients requiring laparotomy, blood samples obtained 72, 48, 24, and 12 h before the laparotomy were additionally measured and compared to all other patients (control group). Results Laparotomy was performed in 18 patients at 11±7 days after cardiac surgery. MESI was found in 9/18 patients. Already 1 h after cardiac surgery, the serum concentrations of D-lactate (37±18 vs. 25±20 nmol/mL, p<0.01) and αGST (82±126 vs. 727±1382 μg/L, p<0.01) in patients undergoing laparotomy were increased compared to the control group. Between patients with and without MESI, differences were only found for iFABP 24 h after cardiac surgery (1.1±0.4 vs. 2.9±0.6 ng/mL, p=0.04) and up to 72 h before laparotomy (0.56±0.72 vs. 2.51±1.96 ng/mL, p=0.01). Conclusions D-lactate and αGST were early markers for gastrointestinal complications after cardiac surgery. Before laparotomy, lowered iFABP levels indicated MESI. Routinely used, these markers can help identify patients with gastrointestinal complications after cardiac surgery early, and might be useful for the evaluation of new therapeutic or preventive strategies.
Collapse
|
2
|
Autodigestion by migrated trypsin is a major factor in small intestinal ischemia-reperfusion injury. J Surg Res 2017; 219:266-278. [DOI: 10.1016/j.jss.2017.05.084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 04/16/2017] [Accepted: 05/23/2017] [Indexed: 01/01/2023]
|
3
|
Impact of Acute Intestinal Ischemia and Reperfusion Injury on Hemodynamics and Remote Organs in a Rat Model. Thorac Cardiovasc Surg 2017; 66:99-108. [PMID: 28655065 DOI: 10.1055/s-0037-1603935] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Acute mesenteric ischemia following cardiovascular surgery is a rare but fatal complication. We established a new rat model for hemodynamic monitoring during mesenteric ischemia/reperfusion (I/R) and evaluated the impact of mesenteric I/R on hemodynamics and remote organ injury. METHODS Mesenteric I/R was induced in male Wistar rats by superior mesenteric artery occlusion for 90 minutes, followed by 120 minutes of reperfusion. Before I/R, ventilation and hemodynamic monitoring including mean arterial blood pressure (MAP) and cardiac output (CO) were established. During reperfusion Geloplasma (I/R + Geloplasma, N = 6) and Ringer's solution (I/R + Ringer, N = 6) were titrated according to CO and compared with I/R without volume resuscitation (I/R only, N = 6) and a sham group (sham, N = 6). Blood samples were regularly taken for serum marker measurements. After reperfusion organs were harvested for histology studies. RESULTS After acute mesenteric I/R, MAP and CO decreased (p < 0.01) while systemic and pulmonary vascular resistance increased (p < 0.01) continuously in the I/R group. Volume substitution according to CO initially stabilized hemodynamic parameters, but CO declined independently in the late stage. Compared with the I/R + Ringer group, the I/R + Geloplasma group required less volume for resuscitation (p < 0.01), experienced less metabolic acidosis. I/R groups had more organ injuries, more neutrophils sequestration, and higher creatine phosphokinase-MB levels than sham group. CONCLUSION A new model for CO monitoring after mesenteric I/R injury demonstrated severe hypovolemic shock during reperfusion followed by remote myocardial and lung injury. Far less colloid volume is needed for hemodynamic stabilization after I/R compared with crystalloid volume.
Collapse
|
4
|
|
5
|
Melatonin reduces changes to small intestinal microvasculature during systemic inflammation. J Surg Res 2017; 211:114-125. [DOI: 10.1016/j.jss.2016.11.055] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 10/26/2016] [Accepted: 11/30/2016] [Indexed: 12/15/2022]
|
6
|
Citrate shows protective effects on cardiovascular and renal function in ischemia-induced acute kidney injury. BMC Nephrol 2017; 18:130. [PMID: 28395656 PMCID: PMC5387390 DOI: 10.1186/s12882-017-0546-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 04/01/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Ischemia and reperfusion (I/R) is one of the major causes of acute kidney injury (AKI). Citrate reduces hypoxia-induced mitochondrial energetic deficits in isolated proximal tubules. Moreover, citrate anticoagulation is now frequently used in renal replacement therapy. In the present study a rat model of I/R-induced AKI was utilized to examine renal protection by citrate in vivo. METHODS AKI was induced by bilateral renal clamping (40 min) followed by reperfusion (3 h). Citrate was infused at three different concentrations (0.3 mmol/kg/h; 0.6 mmol/kg/h and 1.0 mmol/kg/h) continuously for 60 min before and 45 min after ischemia. Plasma calcium concentrations were kept stable by infusion of calcium gluconate. The effect of citrate was evaluated by biomonitoring, blood and plasma parameters, histopathology and tissue ATP content. RESULTS In comparison to the normoxic control group bilateral renal ischemia led to an increase of creatinine and lactate dehydrogenase activity and a decrease in tissue ATP content and was accompanied by a drop in mean arterial blood pressure. Infusion of 1.0 mmol/kg/h citrate led to lower creatinine and reduced LDH activity compared to the I/R control group and a tendency for higher tissue ATP content. Pre-ischemic infusion of 1.0 mmol/kg/h citrate stabilized blood pressure during ischemia. CONCLUSIONS Citrate has a protective effect during I/R-induced AKI, possibly by limiting the mitochondrial deficit as well as by beneficial cardiovascular effects. This strengthens the rationale of using citrate in continuous renal replacement therapy and encourages consideration of citrate infusion as a therapeutic treatment for AKI in humans.
Collapse
|
7
|
Transient dilutional acidosis but no lactic acidosis upon cardiopulmonary bypass in patients undergoing coronary artery bypass grafting. Arch Med Sci 2017; 13:585-590. [PMID: 28507572 PMCID: PMC5420618 DOI: 10.5114/aoms.2016.58144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 06/19/2015] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION Dilutional acidosis may result from the introduction of a large fluid volume into the patients' systemic circulation, resulting in a considerable dilution of endogenous bicarbonate in the presence of a constant carbon dioxide partial pressure. Its significance or even existence, however, has been strongly questioned. Blood gas samples of patients operated on with standard cardiopulmonary bypass (CPB) were analyzed in order to provide further evidence for the existence of dilutional acidosis. MATERIAL AND METHODS Between 07/2014 and 10/2014, a total of 25 consecutive patients scheduled for elective isolated coronary artery bypass grafting with CPB were enrolled in this prospective observational study. Blood gas samples taken regularly after CPB initiation were analyzed for dilutional effects and acid-base changes. RESULTS After CPB initiation, hemoglobin concentration dropped from an average initial value of 12.8 g/dl to 8.8 g/dl. Before the beginning of CPB, the mean value of the patients' pH and base excess (BE) value averaged 7.41 and 0.5 mEq/l, respectively. After the onset of CPB, pH and BE values significantly dropped to a mean value of 7.33 (p < 0.0001) and -3.3 mEq/l (p < 0.0001), respectively, within the first 20 min. In the following period during CPB they recovered to 7.38 and -0.5 mEq/l, respectively, on average. Patients did not show overt lactic acidosis. CONCLUSIONS The present data underline the general existence of dilutional acidosis, albeit very limited in its duration. In patients undergoing coronary artery bypass grafting it seems to be the only obvious disturbance in acid-base homeostasis during CPB.
Collapse
|
8
|
Hypokalemia during acute metabolic acidosis on hemodilution with succinylated gelatin in rats. J Surg Res 2017; 209:45-52. [DOI: 10.1016/j.jss.2016.09.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 09/19/2016] [Accepted: 09/27/2016] [Indexed: 11/16/2022]
|
9
|
Tranexamic acid prolongs survival after controlled hemorrhage in rats. J Surg Res 2016; 208:104-110. [PMID: 27993197 DOI: 10.1016/j.jss.2016.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 08/24/2016] [Accepted: 09/09/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND The plasmin/plasminogen inhibitor tranexamic acid (TXA) is mainly used in elective surgeries with a higher blood loss to avoid uncontrolled bleeding. Recently, TXA has also been shown to reduce mortality in trauma patients. It is assumed that its beneficial effects are principally caused by its antifibrinolytic properties. We hypothesize that TXA also improves survival in a modified Wigger's model of hemorrhagic shock by a mechanism other than antifibrinolysis. MATERIALS AND METHODS Male Wistar rats were intermittently bled until the mean arterial blood pressure was dropped to 25-30 mm Hg (severe shock). After shock induction, the animals received either 0.14-0.15 mL TXA (30 mg/kg) i.v. or the equivalent volume of 0.9% NaCl given as bolus. Adjacent to the shock period, the rats were resuscitated with Ringer's solution within 30 min and observed for another 150 min unless the animals died earlier. RESULTS In the animals treated with TXA, survival was clearly prolonged and acid-base parameters showed some differences as compared to the animals receiving only NaCl. In the model used, coagulation slightly declined, but an increased fibrinolysis was not observed. CONCLUSIONS Since in the applied shock model fibrinolysis is negligible, we postulate that TXA is capable of providing protection against hemorrhagic shock independent from its antifibrinolytic properties.
Collapse
|
10
|
Melatonin does not affect disseminated intravascular coagulation but diminishes decreases in platelet count during subacute endotoxaemia in rats. Thromb Res 2016; 139:38-43. [DOI: 10.1016/j.thromres.2015.10.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/30/2015] [Accepted: 10/13/2015] [Indexed: 12/15/2022]
|
11
|
Impact of bacterial endotoxin on the structure of DMPC membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2271-6. [DOI: 10.1016/j.bbamem.2015.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/03/2015] [Accepted: 06/07/2015] [Indexed: 12/22/2022]
|
12
|
Perfluorodecalin-Filled Poly(n-butyl-cyanoacrylate) Nanocapsules as Potential Artificial Oxygen Carriers: Preclinical Safety and Biocompatibility. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2015; 15:5637-5648. [PMID: 26369130 DOI: 10.1166/jnn.2015.10044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
With regard to the development of artificial blood substitutes, perfluorodecalin-filled poly(n-butyl-cyanoacrylate) nanocapsules are already discussed for the use as artificial oxygen carriers. The aim of the present study was to thoroughly investigate the preclinical safety and biocompatibility of the perfluorodecalin-filled poly(n-butyl-cyanoacrylate) nanocapsules prepared by interfacial polymerization. Nanocapsules were assessed for physical and microbial stability. Subsequent to intravenous infusion to anesthetized rats, effects on systemic parameters, microcirculation, circulatory in vivo half-life, acid base/metabolic status, organ damage and biodistribution were evaluated using inter alia 19F-NMR spectroscopy and in vivo microscopy. Perfluorodecalin-filled poly(n-butyl-cyanoacrylate) nanocapsules displayed physical and microbial stability over a period of 4 weeks and the circulatory in vivo half-life was t1/2 = 30 min. In general, all animals tolerated intravenous infusion of the prepared nanocapsules, even though several side-effects occurred. As a consequence of nanocapsule infusion, a transient decrease in mean arterial blood pressure, impairment of hepatic microcirculation, organ/tissue damage of liver, spleen and small intestine, as well as an elevation of plasma enzyme activities such as lactate dehydrogenase, creatine kinase and aspartate aminotransferase could be observed. The assessment of the distribution pattern revealed nanocapsule accumulation in spleen, kidney and small intestine. Perfluorodecalin-filled poly(n-butyl-cyanoacrylate) nanocapsules conformed to basic requirements of drugs under preclinical development but further improvement is needed to establish these nanocapsules as novel artificial oxygen carriers.
Collapse
|
13
|
Abstract
Melatonin has been shown to enhance the immune response under immune-compromised conditions. However, its immune-modulatory effects under inflammatory conditions are unclear at present. Both pro- and anti-inflammation has been reported. To study time-dependent effects of melatonin on the general immune response during endotoxemia in more detail, we used two models in male rats: per-acute endotoxemia was induced by lipopolysaccharide (LPS) bolus injection (2.5 mg/kg), sub-acute endotoxemia by LPS infusion (2.5 mg/kg × h). Melatonin was applied directly before and 2 h after LPS administration (3 mg/kg, each). The LPS-induced formation of the pro-inflammatory cytokines tumor necrosis factor alpha, interferon-gamma, interleukin (IL)-1α/β, IL-5, and IL-6 and of the anti-inflammatory cytokine IL-10 was further amplified by melatonin, although it was only significant during per-acute endotoxemia. In both models, melatonin had no effect on the LPS-induced nitric oxide release. These findings show that exogenous melatonin is capable of enhancing the general immune response under inflammatory conditions.
Collapse
|
14
|
Attenuation of intestinal ischemic injury and shock by physostigmine. J Surg Res 2015; 194:405-414. [DOI: 10.1016/j.jss.2014.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 10/01/2014] [Accepted: 11/04/2014] [Indexed: 01/16/2023]
|
15
|
Severe blunt muscle trauma in rats: only marginal hypoxia in the injured area. PLoS One 2014; 9:e111151. [PMID: 25360779 PMCID: PMC4215885 DOI: 10.1371/journal.pone.0111151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 09/29/2014] [Indexed: 12/17/2022] Open
Abstract
Background After severe muscle trauma, hypoxia due to microvascular perfusion failure is generally believed to further increase local injury and to impair healing. However, detailed analysis of hypoxia at the cellular level is missing. Therefore, in the present work, spectroscopic measurements of microvascular blood flow and O2 supply were combined with immunological detection of hypoxic cells to estimate O2 conditions within the injured muscle area. Materials and Methods Severe blunt muscle trauma was induced in the right Musculus gastrocnemius of male Wistar rats by a standardized “weight-drop” device. Microvascular blood flow, relative hemoglobin amount, and hemoglobin O2 saturation were determined by laser Doppler and white-light spectroscopy. Hypoxic cells were detected by histologic evaluation of covalent binding of pimonidazole and expression of HIF-1α. Results Directly after trauma and until the end of experiment (480 minutes), microvascular blood flow and relative hemoglobin amount were clearly increased. In contrast to blood flow and relative hemoglobin amount, there was no immediate but a delayed increase of microvascular hemoglobin O2 saturation. Pimonidazole immunostaining revealed a hypoxic fraction (percentage area of pimonidazole-labelled muscle cells within the injured area) between 8 to 3%. There was almost no HIF-1α expression detectable in the muscle cells under each condition studied. Conclusions In the early phase (up to 8 hours) after severe blunt muscle trauma, the overall microvascular perfusion of the injured area and thus its O2 supply is clearly increased. This increased O2 supply is obviously sufficient to ensure normoxic (or even hyperoxic) conditions in the vast majority of the cells.
Collapse
|
16
|
Glycine selectively reduces intestinal injury during endotoxemia. J Surg Res 2014; 192:592-8. [PMID: 25012270 DOI: 10.1016/j.jss.2014.06.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/04/2014] [Accepted: 06/06/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Glycine is well known to protect the intestine against ischemia-reperfusion injury and during mechanical manipulation. Here, we studied whether glycine protects the small intestine during endotoxemia, even without being the site of the infection. MATERIALS AND METHODS Lipopolysaccharide (LPS) was infused at a rate of 1 mg/kg × h over a period of 7 h (subacute endotoxemia) in male Wistar rats. Glycine (single dose: 50 mg/kg × 15 min) was applied intravenously at 180 and 270 min after the beginning of the LPS infusion. Systemic parameters were periodically determined. The small intestine was analyzed for macroscopic (hemorrhages) and histopathologic changes (hematoxylin and eosin staining), and markers of inflammation (myeloperoxidase activity). RESULTS Glycine neither decreased mortality nor beneficially affected vital parameters (e.g., mean arterial blood pressure and breathing rate), electrolytes, blood gases including pH and base excess, and plasma parameters of tissue injury such as lactate concentration, hemolysis, and aminotransferases activities during experimental endotoxemia. It, however, specifically diminished the LPS-induced small intestinal injury, as indicated by less intestinal accumulation of blood, less intestinal hemorrhages, and reduced intestinal hemoglobin content. CONCLUSIONS The present results demonstrate that glycine selectively protects the small intestine during subacute endotoxemia, even after manifestation of a severe systemic impairment. Because glycine is non-toxic at low doses, an administration of a moderate glycine dose (50-100 mg/kg) may be suitable to protect from intestinal damage during sepsis. Its true clinical potential, however, needs to be verified in further experimental studies and clinical trials.
Collapse
|
17
|
Safety of poly (ethylene glycol)-coated perfluorodecalin-filled poly (lactide-co-glycolide) microcapsules following intravenous administration of high amounts in rats. RESULTS IN PHARMA SCIENCES 2014; 4:8-18. [PMID: 25756002 PMCID: PMC4050377 DOI: 10.1016/j.rinphs.2014.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/24/2014] [Accepted: 04/28/2014] [Indexed: 01/05/2023]
Abstract
The host response against foreign materials designates the biocompatibility of intravenously administered microcapsules and thus, widely affects their potential for subsequent clinical use as artificial oxygen/drug carriers. Therefore, body distribution and systemic parameters, as well as markers of inflammation and indicators of organ damage were carefully evaluated after administration of short-chained poly (vinyl alcohol, (PVA)) solution or poly (ethylene glycol (PEG))-shielded perfluorodecalin-filled poly (d,l-lactide-co-glycolide, PFD-filled PLGA) microcapsules into Wistar rats. Whereas PVA infusion was well tolerated, all animals survived the selected dose of 1247 mg microcapsules/kg body weight but showed marked toxicity (increased enzyme activities, rising pro-inflammatory cytokines and complement factors) and developed a mild metabolic acidosis. The observed hypotension emerging immediately after start of capsule infusion was transient and mean arterial blood pressure restored to baseline within 70 min. Microcapsules accumulated in spleen and liver (but not in other organs) and partly occluded hepatic microcirculation reducing sinusoidal perfusion rate by about 20%. Intravenous infusion of high amounts of PFD-filled PLGA microcapsules was tolerated temporarily but associated with severe side effects such as hypotension and organ damage. Short-chained PVA displays excellent biocompatibility and thus, can be utilized as emulsifier for the preparation of drug carriers designed for intravenous use.
Collapse
Key Words
- ALAT, alanine aminotransferase
- ANOVA, one-way analysis of variance
- ASAT, aspartate aminotransferase
- Artificial oxygen carriers
- BE, base excess
- Biocompatibility
- Biodegradable microcapsules
- C3, complement factor 3
- C4a, complement factor 4a
- CARPA, complement activation-related pseudoallergy
- CK, creatine kinase
- DAPI, 4',6-diamidin-2-phenylindol
- FITC-dextran, fluorescein isothiocyanate-dextran 150,000
- IFN-?, interferon-gamma
- IL, interleukin
- IVM, intravital microscopy
- LDH, lactate dehydrogenase
- MAP, mean arterial blood pressure
- PEG, poly (ethylene glycol)
- PFD, perfluorodecalin
- PLA)
- PLGA, poly (d,l-lactide-co-glycolide)
- PVA, poly (vinyl alcohol)
- Perfluorocarbon
- Poly (lactic/glycolic) acid (PLGA
- Poly (vinyl alcohol)
- TNF-a, tumor necrosis factor alpha
- pO2, pCO2, oxygen and carbon dioxide partial pressures
Collapse
|
18
|
Volume replacement with Ringer-lactate is detrimental in severe hemorrhagic shock but protective in moderate hemorrhagic shock: studies in a rat model. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:R5. [PMID: 24393404 PMCID: PMC4057456 DOI: 10.1186/cc13182] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 12/30/2013] [Indexed: 11/10/2022]
Abstract
INTRODUCTION To date, there are insufficient data demonstrating the benefits of preclinically administered Ringer-lactate (RL) for the treatment of hemorrhagic shock following trauma. Recent animal experiments have shown that lactate tends to have toxic effects in severe hemorrhagic shock. This study aimed to compare the effects of RL administered in a rat model of severe hemorrhagic shock (mean arterial blood pressure (MAP): 25 to 30 mmHg) and moderate hemorrhagic shock (MAP: 40 to 45 mmHg). METHODS Four experimental groups of eight male Wistar rats each (moderate shock with Ringer-saline (RS), moderate shock with RL, severe shock with RS, severe shock with RL) were established. After achieving the specified depth of shock, animals were maintained under the shock conditions for 60 minutes. Subsequently, reperfusion with RS or RL was performed for 30 minutes, and the animals were observed for an additional 150 minutes. RESULTS All animals with moderate shock that received RL survived the entire study period, while six animals with moderate shock that received RS died before the end of the experiment. Furthermore, animals with moderate shock that received RL exhibited considerable improvements in their acid-base parameters and reduced organ damage. CONCLUSIONS The preclinical use of RL for volume replacement has different effects depending on the severity of hemorrhagic shock. RL exhibits detrimental effects in cases of severe shock, whereas it has pronounced protective effects in cases of moderate shock.
Collapse
|
19
|
Artificial oxygen carriers based on perfluorodecalin-filled poly(n-butyl-cyanoacrylate) nanocapsules. J Microencapsul 2013; 31:284-92. [DOI: 10.3109/02652048.2013.843600] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
20
|
Superiority of acetate compared with lactate in a rodent model of severe hemorrhagic shock. J Surg Res 2013; 186:338-45. [PMID: 24124975 DOI: 10.1016/j.jss.2013.09.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Recently, we have shown that the use of lactated Ringer's (LR) solution is inferior to pure Ringer's solution (RS) in treatment of severe hemorrhagic shock in rats. The present study was performed to evaluate whether this is a specific effect of lactate or also applies to another metabolizable anion, namely acetate. MATERIAL AND METHODS We subjected male Wistar rats to hemorrhagic shock by dropping the mean arterial blood pressure to 25-30 mm Hg for 60 min, resuscitated with acetated Ringer's (AR) solution, LR solution, RS, or normal saline (NS) within 30 min, and further observed the animals for 180 min. RESULTS Administration of AR solution prolonged median survival to 115 min compared with 50 min for resuscitation with LR solution or 85 and 90 min for NS and RS, respectively. Resuscitation with AR solution and LR solution clearly improved metabolic acidosis compared with NS and RS but tissue injury, indicated by plasma enzyme activities, was most pronounced in the LR solution group, medium in the NS and RS groups, and least in the AR solution group. CONCLUSIONS In severe hemorrhagic shock, resuscitation with both RS and NS is superior to administration of LR solution but initial outcome is even further improved if AR solution is used. Mere amelioration of the acid-base status by AR solution may explain its superior role compared with RS and NS but cannot be responsible for its superiority compared with LR solution. Here, direct injury by lactate has to be discussed.
Collapse
|
21
|
Acid-base and electrolyte status during normovolemic hemodilution with succinylated gelatin or HES-containing volume replacement solutions in rats. PLoS One 2013; 8:e72848. [PMID: 24023785 PMCID: PMC3759408 DOI: 10.1371/journal.pone.0072848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/15/2013] [Indexed: 11/25/2022] Open
Abstract
Background In the past, several studies have compared different colloidal replacement solutions, whereby the focus was usually on the respective colloid. We therefore systematically studied the influence of the carrier solution’s composition of five approved colloidal volume replacement solutions (Gelafundin, Gelafusal, Geloplasma, Voluven and Volulyte) on acid-base as well as electrolyte status during and following acute severe normovolemic hemodilution. The solutions differed in the colloid used (succinylated gelatin vs. HES) and in the presence and concentration of metabolizable anions as well as in their electrolyte composition. Methods Anesthetized Wistar rats were subjected to a stepwise normovolemic hemodilution with one of the solutions until a final hematocrit of 10%. Subsequent to dilution (162 min), animals were observed for an additional period (150 min). During dilution and observation time blood gas analyses were performed eight times in total. Additionally, in the Voluven and Volulyte groups as well as in 6 Gelafundin animals, electrolyte concentrations, glucose, pH and succinylated gelatin were measured in urine and histopathological evaluation of the kidney was performed. Results All animals survived without any indications of injury. Although the employed solutions differed in their respective composition, comparable results in all plasma acid-base and electrolyte parameters studied were obtained. Plasma pH increased from approximately 7.28 to 7.39, the plasma K+ concentration decreased from circa 5.20 mM to 4.80-3.90 mM and the plasma Cl− concentration rose from approximately 105 mM to 111–120 mM. Urinary analysis revealed increased excretion of K+, H+ and Cl−. Conclusions The present data suggest that the carrier solution’s composition with regard to metabolizable anions as well as K+, Ca2+ only has a minor impact on acid-base and electrolyte status after application of succinylated gelatin or HES-containing colloidal volume replacement solutions.
Collapse
|
22
|
Effects of glycine, pyruvate, resveratrol, and nitrite on tissue injury and cytokine response in endotoxemic rats. J Surg Res 2013; 183:e7-e21. [DOI: 10.1016/j.jss.2013.01.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/15/2012] [Accepted: 01/11/2013] [Indexed: 12/15/2022]
|
23
|
Long-circulating poly(ethylene glycol)-coated poly(lactid-co-glycolid) microcapsules as potential carriers for intravenously administered drugs. J Microencapsul 2013; 30:632-42. [DOI: 10.3109/02652048.2013.770098] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
24
|
Myriocin, an inhibitor of serine palmitoyl transferase, impairs the uptake of transferrin and low-density lipoprotein in mammalian cells. Arch Biochem Biophys 2012; 526:60-8. [PMID: 22841978 DOI: 10.1016/j.abb.2012.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 07/09/2012] [Accepted: 07/10/2012] [Indexed: 11/29/2022]
Abstract
The role of sphingolipids in clathrin-mediated endocytosis is only poorly understood in mammalian cells. Thus the relationship between sphingolipid de novo synthesis and clathrin-mediated endocytosis of transferrin were studied in L929 fibroblasts and two other cell lines. Endocytosis was measured using live cell imaging with fluorescent transferrin or (125)I-transferrin. Lipids were primarily measured using electrospray ionization tandem mass spectrometry. At physiological temperature, transferrin uptake was significantly decreased by the inhibitor of serine palmitoyl transferase myriocin. Myriocin inhibited also the uptake of low-density lipoproteins. The endocytosis inhibition by myriocin could be released by the addition of sphingoid base and by the protein phosphorylation effectors phorbol-12-myristate, 13-acetate (PMA) and okadaic acid. Myriocin influenced not only sphingolipids but also the glycerophospholipid profile. The study of phosphatidylcholine species shows adaptations to more saturated, alkylated and longer fatty acid moieties. The reported results imply that in mammalian cells, at 37°C, sphingolipid de novo synthesis is required for clathrin-mediated endocytosis.
Collapse
|
25
|
Glycine, a simple physiological compound protecting by yet puzzling mechanism(s) against ischaemia-reperfusion injury: current knowledge. Br J Pharmacol 2012; 165:2059-72. [PMID: 22044190 DOI: 10.1111/j.1476-5381.2011.01711.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ischaemia is amongst the leading causes of death. Despite this importance, there are only a few therapeutic approaches to protect from ischaemia-reperfusion injury (IRI). In experimental studies, the amino acid glycine effectively protected from IRI. In the prevention of IRI by glycine in cells and isolated perfused or cold-stored organs (tissues), direct cytoprotection plays a crucial role, most likely by prevention of the formation of pathological plasma membrane pores. Under in vivo conditions, the mechanism of protection by glycine is less clear, partly due to the physiological presence of the amino acid. Here, inhibition of the inflammatory response in the injured tissue is considered to contribute decisively to the glycine-induced reduction of IRI. However, attenuation of IRI recently achieved in experimental animals by low-dose glycine treatment regimens suggests additional/other (unknown) protective mechanisms. Despite the convincing experimental evidence and the large therapeutic width of glycine, there are only a few clinical trials on the protection from IRI by glycine with ambivalent results. Thus, both the mechanism(s) behind the protection of glycine against IRI in vivo and its true clinical potential remain to be addressed in future experimental studies/clinical trials.
Collapse
|
26
|
Free hemoglobin concentration in severe sepsis: methods of measurement and prediction of outcome. Crit Care 2012; 16:R125. [PMID: 22800762 PMCID: PMC3580706 DOI: 10.1186/cc11425] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 07/16/2012] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Hemolysis can be induced in sepsis via various mechanisms, its pathophysiological importance has been demonstrated in experimental sepsis. However, no data on free hemoglobin concentrations in human sepsis are available. In the present study we measured free hemoglobin in patients with severe sepsis as well as in postoperative patients using four methods. It was our aim to determine the potential value of free hemoglobin as a biomarker for diagnosis and outcome of severe sepsis in critical illness. METHODS Plasma concentration of free hemoglobin was determined in patients with severe sepsis (n = 161) and postoperative patients (n = 136) on day 1 of diagnosis and surgery. For the measurement of free hemoglobin, an enzyme linked immunosorbent assay and three spectrophotometric algorithms were used. Moreover, SAPS II- and SOFA scores as well as procalcitonin concentration and outcome were determined. Kaplan-Meier analysis was performed and odds ratios were determined after classification of free hemoglobin concentrations in a high and low concentration group according to the median. For statistical evaluation the Mann-Whitney test and logistic regression analysis were used. RESULTS In non-survivors of severe sepsis, free hemoglobin concentration was twice the concentration compared to survivors. Thirty-day survival of patients, as evidenced by Kaplan-Meier analysis, was markedly lower in patients with high free hemoglobin concentration than in patients with low free hemoglobin concentration. Best discrimination of outcome was achieved with the spectrophotometric method of Harboe (51.3% vs. 86.4% survival, p < 0.001; odds ratio 6.1). Multivariate analysis including free hemoglobin, age, SAPS II- and SOFA-score and procalcitonin demonstrated that free hemoglobin, as determined by all 4 methods, was the best and an independent predictor for death in severe sepsis (p = 0.022 to p < 0.001). Free hemoglobin concentrations were not significantly different in postoperative and septic patients in three of four assays. Thus, free hemoglobin can not be used to diagnose severe sepsis in critical illness. CONCLUSIONS Free hemoglobin is an important new predictor of survival in severe sepsis.
Collapse
|
27
|
Adverse effects of α-ketoglutarate/malate in a rat model of acute kidney injury. Am J Physiol Renal Physiol 2012; 303:F56-63. [PMID: 22513847 PMCID: PMC3431145 DOI: 10.1152/ajprenal.00070.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/11/2012] [Indexed: 01/22/2023] Open
Abstract
Acute kidney injury (AKI) is the most common kidney disease in hospitalized patients with high mortality. Ischemia and reperfusion (I/R) is one of the major causes of AKI. The combination of α-ketoglutarate+malate (αKG/MAL) showed the ability to reduce hypoxia-induced damage to isolated proximal tubules. The present study utilizes a rat model of I/R-induced AKI accompanied by intensive biomonitoring to examine whether αKG/MAL provides protection in vivo. AKI was induced in male Sprague-Dawley rats by bilateral renal clamping (40 min) followed by reperfusion (240 min). αKG/MAL was infused continuously for 60 min before and 45 min after ischemia. Normoxic and I/R control groups received 0.9% NaCl solution. The effect of αKG/MAL was evaluated by biomonitoring, blood and plasma parameters, histopathology, and immunohistochemical staining for kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), as well as by determination of tissue ATP and nonesterified fatty acid concentrations. Intravenous infusion of αKG/MAL at a cumulative dose of 1 mmol/kg each (146 mg/kg αKG and 134 mg/kg MAL) did not prevent I/R-induced increases in plasma creatinine, histopathological alterations, or cortical ATP depletion. On the contrary, the most notable adverse affect in animals receiving αKG/MAL was the decrease in mean arterial blood pressure, which was also accompanied by a reduction in heart rate. Supplementation with αKG/MAL, which is very protective against hypoxia-induced injury in isolated proximal tubules, does not protect against I/R-induced renal injury in vivo, possibly due to cardiovascular depressive effects.
Collapse
|
28
|
Ascorbic acid reduction of compound I of mammalian catalases proceeds via specific binding to the NADPH binding pocket. Biochemistry 2012; 51:4693-703. [PMID: 22616883 DOI: 10.1021/bi2017602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian (Clade 3) catalases utilize NADPH as a protective cofactor to prevent one-electron reduction of the central reactive intermediate Compound I (Cpd I) to the catalytically inactive Compound II (Cpd II) species by re-reduction of Cpd I to the enzyme's resting state (ferricatalase). It has long been known that ascorbate/ascorbic acid is capable of reducing Cpd I of NADPH-binding catalases to Cpd II, but the mode of this one-electron reduction had hitherto not been explored. We here demonstrate that ascorbate-mediated reduction of Cpd I, generated by addition of peroxoacetic acid to NADPH-free bovine liver catalase (BLC), requires specific binding of the ascorbate anion to the NADPH binding pocket. Ascorbate-mediated Cpd II formation was found to be suppressed by added NADPH in a concentration-dependent manner, for the achievement of complete suppression at a stoichiometric 1:1 NADPH:heme concentration ratio. Cpd I → Cpd II reduction by ascorbate was similarly inhibited by addition of NADH, NADP(+), thio-NADP(+), or NAD(+), though with 0.5-, 0.1-, 0.1-, and 0.01-fold reduced efficiencies, respectively, in agreement with the relative binding affinities of these dinucleotides. Unexpected was the observation that although Cpd II formation is not observed in the presence of NADP(+), the decay of Cpd I is slightly accelerated by ascorbate rather than retarded, leading to direct regeneration of ferricatalase. The experimental findings are supported by molecular mechanics docking computations, which show a similar binding of NADPH, NADP(+), and NADH, but not NAD(+), as found in the X-ray structure of NADPH-loaded human erythrocyte catalase. The computations suggest that two ascorbate molecules may occupy the empty NADPH pocket, preferably binding to the adenine binding site. The biological relevance of these findings is discussed.
Collapse
|
29
|
Mesenteric ischemia-reperfusion injury: clearly improved hemodynamics but only minor protection of the rat small intestine by (sub)therapeutic heparin sodium and enoxaparin doses. J Surg Res 2012; 179:e57-69. [PMID: 22494914 DOI: 10.1016/j.jss.2012.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 11/17/2011] [Accepted: 01/03/2012] [Indexed: 12/28/2022]
Abstract
BACKGROUND Tissue protection against ischemia (I)/reperfusion (R) injury by heparins can be due to their anticoagulant and/or non-anticoagulant properties. Here we studied the protective potential of the anticoagulant and the non-anticoagulant features of heparin sodium (HepSo) and enoxaparin (Enox) against mesenteric I/R injury in a rat model. MATERIALS AND METHODS Mesenteric I/R was induced in rats (n = 6 per group) by superior mesenteric artery occlusion (SMAO; 90 min) and reopening (120 min). Therapeutic/clinical and subtherapeutic/non-anticoagulant doses of HepSo (0.25 mg/kg bolus + 0.25 mg/kg × h; 0.05 mg/kg bolus + 0.1 mg/kg × h) or Enox (0.5 mg/kg bolus + 0.5 mg/kg × h; 0.05 mg/kg bolus + 0.1 mg/kg × h) were administered intravenously starting 30 min before SMAO to the end of reperfusion. Systemic/vital and intestinal microcirculatory parameters were measured during the whole experimental procedure, those of small intestine injury at the end. RESULTS During intestinal reperfusion, mean arterial blood pressure and heart rates were significantly increased by HepSo and, less effectively, by Enox, in a dose-dependent manner. Intestinal microcirculation was only affected by the therapeutic HepSo dose, which decreased the microvascular flow and S(O2) during reperfusion. The subtherapeutic Enox treatment, as opposed to any HepSo dose, most effectively diminished I/R-induced intestinal hemorrhages, myeloperoxidase activity (as a measure of neutrophil invasion), and histopathological changes. CONCLUSION Therapeutic but, to a lesser extent, also the subtherapeutic doses of both HepSo and Enox clearly improve hemodynamics during mesenteric reperfusion, while intestinal protection is exclusively provided by Enox, especially at its subtherapeutic dose. Alterations in intestinal microcirculation are not responsible for these effects. Thus, non-anticoagulant Enox doses and, preferably, heparin(oid)s unable to affect coagulation, could diminish clinical risks of I/R-induced gastrointestinal complications.
Collapse
|
30
|
Reduction of chronic graft injury with a new HTK-based preservation solution in a murine heart transplantation model. Cryobiology 2012; 64:273-8. [PMID: 22406211 DOI: 10.1016/j.cryobiol.2012.02.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 02/18/2012] [Accepted: 02/20/2012] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Aim of this study was to evaluate a new histidine-tryptophan-ketoglutarate (HTK)-based preservation solution on chronic isograft injury in comparison to traditional HTK solution. METHODS Hearts of C57BL/6J (H-2b) mice were stored for 15 h in 0-4 °C cold preservation solution and then transplanted heterotopically into C57BL/6J (H-2b) mice. Three groups were evaluated: HTK, the base solution of a new preservation solution and hearts without cold ischemia (control). Time to restoration of heartbeat was measured (re-beating time). Strength of the heartbeat was palpated daily and scored on a 4-level scale (palpation score). Animals were sacrificed after 60 days of observation (24 h for TGF-β expression). The transplanted hearts were evaluated histologically for myocardial damage, vasculopathy and interstitial fibrosis. TGF-β expression was assessed immunohistologically. All investigators were blinded to the groups. ANOVA and LSD post hoc test were used for statistical analysis. RESULTS The re-beating time was significantly shorter in hearts stored in the new solution (10.3±2.6 min vs. HTK 14.2±4.1 min; p<0.05). The palpation score was significantly higher in hearts stored in the new solution (2.3±0.4 vs. HTK 1.6±0.5; p<0.01). Hearts stored in the new solution showed a lower myocardial injury score (1.8±0.2 vs. HTK 2.2±0.7), less interstitial fibrosis (4.8±1.9% vs. HTK 8.5±3.8%, p<0.05), less vasculopathy (14.7±6.9% vs. 22.0±23.2%; p=0.06) and lower TGF-β1-expression (6.6±1.4% vs. HTK 12.0±4.6%). CONCLUSION The new HTK-based solution reduces the chronic isograft injury. This protective effect is likely achieved through several modifications and supplements into the new solution like N-acetyl-L-histidine, glycine, alanine, arginine and sucrose.
Collapse
|
31
|
Toluidine blue for the intraoperative staining of the ureters. Studies on the safe administration in rats. Langenbecks Arch Surg 2012; 397:983-93. [DOI: 10.1007/s00423-012-0907-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/10/2012] [Indexed: 10/14/2022]
|
32
|
A new preservation solution for lung transplantation: evaluation in a porcine transplantation model. J Heart Lung Transplant 2012; 31:310-7. [PMID: 22226803 DOI: 10.1016/j.healun.2011.11.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 11/05/2011] [Accepted: 11/25/2011] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Lung preservation injury is still a major problem in lung transplantation. The aim of the current study was to evaluate the effects of a new preservation solution (Custodiol-N) for lung preservation. METHODS Using an in vivo pig model, 7 lungs each were preserved for 24 hours after perfusion with: low-potassium dextran (LPD) solution as control (Group I); base solution of Custodiol-N without iron chelators (Group II); Custodiol-N (Group III); or Custodiol-N supplemented with dextran 40 (Group IV). Four animals received a sham operation. After left lung transplantation and contralateral lung exclusion, hemodynamics and blood gases were monitored for 6 hours; tissue samples were taken at the end of the experiments. RESULTS All animals survived the transplantation procedure. Base solution- and Custodiol-N-preserved lungs (Groups II and III) showed graft function similar to that of LPD-preserved lungs (Group I), showing a trend toward improved values. Custodiol-N with dextran (Group IV) led to a significant reduction of mean pulmonary arterial pressure (20 ± 2 vs 28 ± 3 mm Hg, p < 0.01) and pulmonary vascular resistance (410 ± 51 vs 588 ± 83 dyne/s/cm(5), p < 0.01), and oxygenation ratio was significantly higher (536 ± 52 vs 313 ± 107 mm Hg at 6 hours, p < 0.01) and PCO(2) values were significantly lower (51 ± 9 vs 77 ± 5 mm Hg at 6 hours, p < 0.01) at 6 hours compared with LPD (Group I). Custodiol-N (Groups II to IV) showed a trend toward a lower wet/dry ratio and reduced oxidative stress; in the presence of dextran (Group IV), the difference was again statistically significant, when compared with LPD (Group I). CONCLUSIONS Custodiol-N solution is a new alternative preservation solution for lung transplantation that offers significantly superior protection compared with LPD when dextran 40 is added.
Collapse
|
33
|
A new model of severe hemorrhagic shock in rats. Comp Med 2011; 61:419-426. [PMID: 22330349 PMCID: PMC3193064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 05/28/2011] [Accepted: 07/07/2011] [Indexed: 05/31/2023]
Abstract
We here introduce a fixed-pressure model of hemorrhagic shock in rats that maximizes effects on mean arterial blood pressure (MAP) during shock and yet maintains high reproducibility and controllability. The MAP of rats was adjusted to 25 to 30 mm Hg by blood withdrawals during 30 min. After a shock period of 60 min, rats were resuscitated either with lactated Ringer solution (LR) only or with the collected blood 3-fold diluted with LR (LR + blood) and monitored for further 150 min. Throughout the experiment, vital parameters and plasma marker enzyme activities and creatinine concentration were assessed. Thereafter, liver, kidneys, small intestine, heart, and lung were harvested and evaluated histopathologically. Vital parameters, plasma marker enzyme activities, creatinine concentration, and histopathology indicated pronounced but reliable and reproducible systemic effects and marked organ damage due to hemorrhagic shock and resuscitation. In contrast to rats that received LR + blood, which survived the postresuscitation period, rats receiving LR only invariably died shortly after resuscitation. The hemorrhagic shock model we present here maximally affects MAP and yet is highly reproducible in rats, allowing the study of various aspects of hemorrhagic shock and resuscitation under clinically relevant conditions.
Collapse
|
34
|
Assessment of a chloride-poor versus a chloride-containing version of a modified histidine-tryptophan-ketoglutarate solution in a rat liver transplantation model. Liver Transpl 2011; 17:650-60. [PMID: 21618685 DOI: 10.1002/lt.22275] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent in vitro studies of cold-induced cell injury have revealed the detrimental effects of extracellular chloride on cold-stored isolated rat hepatocytes; however, its influence on endothelial cells is beneficial. To determine which of these effects is predominant in vivo, we tested both a chloride-poor variant of a new histidine-tryptophan-ketoglutarate (HTK)-based preservation solution and a chloride-containing variant in a rat liver transplantation model. The study, which was carried out in a blinded fashion with 7 or 8 rats per group, was divided into 2 parts: (1) a comparison of survival in 3 series under different conditions [different microsurgeons, rat strains, cold ischemia times (3, 12, and 24 hours), and warm ischemia times] and (2) an assessment of the microcirculation (30-90 minutes after reperfusion), laboratory data, bile production, and histology. In each of the survival experiments, a (strong) tendency toward prolonged survival was observed with the new chloride-containing solution (50% versus 12.5%, 75% versus 37.5%, and 100% versus 71.4% [chloride-containing vs. chloride-poor], overall P < 0.05). Additionally, the sinusoidal perfusion rates (83.9% ± 4.0% versus 69.2% ± 10.8%, P < 0.01) and the red blood cell velocities in sinusoids (147.7 ± 26.7 versus 115.5 ± 26.0 μm/second, P < 0.05) and in postsinusoidal venules (332.4 ± 87.3 versus 205.5 ± 53.5 μm/second, P < 0.01) were clearly higher with chloride. Moreover, the serum activities of liver enzymes were slightly reduced (not significantly), and bile production was significantly increased. These results suggest an overall beneficial effect of chloride in HTK-based liver preservation solutions.
Collapse
|
35
|
Protection by Pyruvate Infusion in a Rat Model of Severe Intestinal Ischemia-Reperfusion Injury. J Surg Res 2011; 167:e93-e101. [DOI: 10.1016/j.jss.2009.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 11/03/2009] [Accepted: 12/08/2009] [Indexed: 11/30/2022]
|
36
|
Cold-induced injury to lung epithelial cells can be inhibited by iron chelators - implications for lung preservation. Eur J Cardiothorac Surg 2011; 40:948-55. [PMID: 21398140 DOI: 10.1016/j.ejcts.2011.01.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 12/17/2010] [Accepted: 01/18/2011] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVES Hypothermia has been shown to lead to cell death via an iron-dependent formation of reactive oxygen species (ROS) in diverse cell types. The susceptibility of lung cells to this injury is unknown - but is of great interest as oxygen is used in lung preservation. Therefore, we studied whether preservation injury to lung epithelial cells can be influenced by iron chelators. METHODS A549 lung epithelial cells were preserved at 4°C for varying periods in either cell culture medium (Dulbecco's Modified Eagle Medium, DMEM), Bretschneider histidine-tryptophan-ketoglutarate (HTK), modified HTK, Celsior, or low potassium dextran (LPD) solution with/without the iron chelators 2,2'-dipyridyl, deferoxamine, or LK 614 and then rewarmed in cell culture medium (for 3h). Lethal cell injury (lactate dehydrogenase (LDH) release or propidium iodide uptake), metabolic activity, morphological alterations, and lipid peroxidation (thiobarbituric acid-reactive substances, TBARS) were assessed. RESULTS Lung epithelial cells sustained substantial damage after cold storage/rewarming (LDH release: DMEM 66±12% and 97±1%, HTK 73±14% and 97±1%, Celsior 81±16% and 97±1%, LPD 39±14% and 96±1% after 24h, n=7, and 7 days, n=6, respectively). TBARS were increased. Iron chelators strongly inhibited the damage in all solutions (LDH release after 7 days' cold storage in the presence of 2,2'-dipyridyl: below 8% in all solutions except LPD, LPD 15±4%). This was confirmed using the other iron chelators and the other parameters of injury. CONCLUSION Hypothermic storage of lung cells leads to iron-dependent oxidative cell injury. These results suggest that the addition of iron chelators to existing or novel preservation solutions might decrease lung preservation injury, and this should now be tested in experimental lung transplantation.
Collapse
|
37
|
Quantification of Ischemia-Reperfusion Injury to the Small Intestine Using a Macroscopic Score. J INVEST SURG 2010; 23:208-17. [DOI: 10.3109/08941931003623622] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
38
|
Abstract
BACKGROUND Living donor liver transplantation subjects the donor to a major hepatectomy. Pharmacological or nutritive protection of the liver during the procedure is desirable to ensure that the remnant is able to maintain sufficient function. The aim of our study was to analyze the effects of pretreatments with alpha-tocopherol (vitamin E), the flavonoid silibinin and/or the amino acid L-glycine on the donor in a rat model. METHODS Male Wistar rats were pretreated with L-glycine (5% in chow, 5 days), alpha-tocopherol (100 mg/kg body weight by gavage, 3 days) and/or silibinin (100 mg/kg body weight, i.p., 5 days). Thereafter, 90% partial hepatectomy was performed without portal vein clamping. RESULTS Glycine pretreatment markedly decreased transaminase release (AST, 12 hr: glycine 1292 +/- 192 U/L, control 2311 +/- 556 U/L, p < .05; ALT, 12 hr: glycine 1013 +/- 278 U/L, control 2038 +/- 500 U/L, p < .05), serum ALP activity and serum bilirubin levels (p < .05). Prothrombin time was reduced, and histologically, liver injury was also decreased in the glycine group. Silibinin pretreatment was less advantageous and pretreatment with alpha-tocopherol at this very high dose showed some adverse effects. Combined, i.e., triple pretreatment was less advantageous than glycine alone. Liver resection induced HIF-1alpha accumulation and HIF-1alpha accumulation was also decreased by glycine pretreatment. CONCLUSION The decrease of liver injury and improvement of liver function after pretreatment with glycine suggests that glycine pretreatment might be beneficial for living liver donors as well as for patients subjected to partial hepatectomy for other reasons.
Collapse
|
39
|
Evaluation of a Modified HTK Solution Containing the New Iron Chelator LK 614 in an Isolated Rat Liver Perfusion Model. J INVEST SURG 2009; 22:340-7. [DOI: 10.1080/08941930903214735] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
40
|
Conversion of the synthetic catalase mimic precursor TAA-1 into the active catalase mimic in isolated hepatocytes. Chem Biol Drug Des 2009; 73:494-501. [PMID: 19366358 DOI: 10.1111/j.1747-0285.2009.00808.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In previous studies we reported on the catalase-like activity and antioxidative properties of a non-heme Fe(III)-tetraaza[14]annulene complex, 5,4-didehydro-5,9,14,18-tetraaza-di(2,2-dimethyl-[5,6]benzo[1,3]dioxolo)[a,h]cyclotetradecene--Fe(III) chloride (TAA-1/Fe). We proposed that intracellular application of the parent, iron-free tetraaza[14]annulene ligand, TAA-1, as precursor would allow antioxidative defense along two lines, i.e. by chelation of potentially toxic cellular iron ions and, subsequently, by catalase-mimic activity. We here set out to establish whether the active catalase mimic is indeed formed intracellularly when cells are loaded with the ligand. When isolated rat hepatocytes were preloaded with TAA-1, they were protected against iron-induced cell injury and oxidative stress elicited by exposure to the membrane-permeable iron complex Fe(III)/8-hydroxyquinoline. After lysis of the cells, followed by ultrafiltration to remove endogenous catalase, the lysate exhibited catalase-like activity, while lysates of control cells not treated with TAA-1 showed no catalase-like activity. By comparison with authentic TAA-1/Fe, an intracellular formation of 2.0 +/- 0.3 microm of the active catalase mimic in native hepatocytes exposed to TAA-1 and of 6.5 +/- 1.0 microm in hepatocytes exposed to both TAA-1 and iron ions was estimated. The intracellular formation of the active catalase mimic thus renders TAA-1 an attractive compound for protection against iron- and/or hydrogen peroxide-dependent cell injuries.
Collapse
|
41
|
Abstract
Triple duty: A synthetic molecular clip traps nicotinamide adenine dinucleotide phosphate (NADP(+); see picture) as well as occupying both the cofactor- and the substrate-binding site in glucose-6-phosphate (G6P) dehydrogenase. This combination of two inhibition mechanisms makes the clip highly effective and selective for this enzyme over other dehydrogenases.
Collapse
|
42
|
No evidence for protective erythropoietin alpha signalling in rat hepatocytes. BMC Gastroenterol 2009; 9:26. [PMID: 19383129 PMCID: PMC2678141 DOI: 10.1186/1471-230x-9-26] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Accepted: 04/21/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recombinant human erythropoietin alpha (rHu-EPO) has been reported to protect the liver of rats and mice from ischemia-reperfusion injury. However, direct protective effects of rHu-EPO on hepatocytes and the responsible signalling pathways have not yet been described. The aim of the present work was to study the protective effect of rHu-EPO on warm hypoxia-reoxygenation and cold-induced injury to hepatocytes and the rHu-EPO-dependent signalling involved. METHODS Loss of viability of isolated rat hepatocytes subjected to hypoxia/reoxygenation or incubated at 4 degrees C followed by rewarming was determined from released lactate dehydrogenase activity in the absence and presence of rHu-EPO (0.2-100 U/ml). Apoptotic nuclear morphology was assessed by fluorescence microscopy using the nuclear fluorophores H33342 and propidium iodide. Erythropoietin receptor (EPOR), EPO and Bcl-2 mRNAs were quantified by real time PCR. Activation of JAK-2, STAT-3 and STAT-5 in hepatocytes and rat livers perfused in situ was assessed by Western blotting. RESULTS In contrast to previous in vivo studies on ischemia-reperfusion injury to the liver, rHu-EPO was without any protective effect on hypoxic injury, hypoxia-reoxygenation injury and cold-induced apoptosis to isolated cultured rat hepatocytes. EPOR mRNA was identified in these cells but specific detection of the EPO receptor protein was not possible due to the lack of antibody specificity. Both, in the cultured rat hepatocytes (10 U/ml for 15 minutes) and in the rat liver perfused in situ with rHu-EPO (8.9 U/ml for 15 minutes) no evidence for EPO-dependent signalling was found as indicated by missing effects of rHu-EPO on phosphorylation of JAK-2, STAT-3 and STAT-5 and on the induction of Bcl-2 mRNA. CONCLUSION Together, these results indicate the absence of any protective EPO signalling in rat hepatocytes. This implies that the protection provided by rHu-EPO in vivo against ischemia-reperfusion and other causes of liver injury is most likely indirect and does not result from a direct effect on hepatocytes.
Collapse
|
43
|
Abstract
Melatonin is easily nitrosated via various mechanisms at the nitrogen atom of the indole ring to give N-nitrosomelatonin (NOMela). This mini-review provides a comprehensive view of this N-nitroso compound. With an improved procedure NOMela can now economically synthesized with low laboratory expenditure. The major chemical property of NOMela, i.e. the (formally) transfer of the NO+ function to its target nucleophile, is explained in detail and a variety of detection methods using this reaction are suggested. As the suspected carcinogenical potential of NOMela is clearly overruled it seems attractive to apply this nitroso compound for endogenous generation of S-nitrosothiols that act as nitric oxide donors in vivo.
Collapse
|
44
|
New insights into the S-nitrosothiol–ascorbate reaction. The formation of nitroxyl. Org Biomol Chem 2009; 7:1954-62. [DOI: 10.1039/b901046g] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
45
|
80. Development of a new vascular preservation solution. Cryobiology 2008. [DOI: 10.1016/j.cryobiol.2008.10.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
46
|
On the functional role of a water molecule in clade 3 catalases: a proposal for the mechanism by which NADPH prevents the formation of compound II. J Am Chem Soc 2008; 130:7345-56. [PMID: 18479132 DOI: 10.1021/ja077787e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
X-ray structures of the 13 different monofunctional heme catalases published to date were scrutinized in order to gain insight in the mechanism by which NADPH in Clade 3 catalases may protect the reactive ferryloxo intermediate Compound I (Cpd I; por (*+)Fe (IV)O) against deactivation to the catalytically inactive intermediate Compound II (Cpd II; porFe (IV)O). Striking similarities in the molecular network of the protein subunits encompassing the heme center and the surface-bound NADPH were found for all of the Clade 3 catalases. Unique features in this region are the presence of a water molecule (W1) adjacent to the 4-vinyl group of heme and a serine residue or a second water molecule hydrogen-bonded to both W1 and the carbonyl group of a threonine-proline linkage, with the proline in van der Waals contact with the dihydronicotinamide group of NADPH. A mechanism is proposed in which a hydroxyl anion released from W1 undergoes reversible nucleophilic addition to the terminal carbon of the 4-vinyl group of Cpd I, thereby producing a neutral porphyrin pi-radical ferryloxo (HO-por (*)Fe (IV)O) species of reduced reactivity. This structure is suggested to be the elusive Cpd II' intermediate proposed in previous studies. An accompanying proton-shifting process along the hydrogen-bonded network is believed to facilitate the NADPH-mediated reduction of Cpd I to ferricatalase and to serve as a funnel for electron transfer from NADPH to the heme center to restore the catalase Fe (III) resting state. The proposed reaction paths were fully supported as chemically reasonable and energetically feasible by means of density functional theory calculations at the (U)B3LYP/6-31G* level. A particularly attractive feature of the present mechanism is that the previously discussed formation of protein-derived radicals is avoided.
Collapse
|
47
|
N-nitrosomelatonin outcompetes S-nitrosocysteine in inhibiting glyceraldehyde 3-phosphate dehydrogenase: first evidence that N-nitrosomelatonin can modify protein function. J Pineal Res 2008; 44:244-9. [PMID: 18339119 DOI: 10.1111/j.1600-079x.2007.00517.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Low-molecular-weight S-nitrosothiols (RSNOs) are well known for their capability to transnitrosate cysteine residues of enzymes thereby altering their catalytic activity. It is unknown, however, whether N-nitrosomelatonin (NOMela) which is highly effective in transnitrosating low-molecular-weight thiols (RSHs) can also alter protein function. In the present study, we report on such a capability with glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a target enzyme. Reaction of NOMela with GAPDH resulted in an increase of RSNOs at the expense of RSHs. Somewhat surprisingly, NOMela was about 10-fold more effective than S-nitrosocysteine in inhibiting GAPDH. Vitamin C and glutathione increased the NOMela-dependent inhibition of the enzyme by accelerating the intermediacy of nitroxyl which is also highly effective in nitrosating RSHs. The occurrence of this intermediate during the NOMela-vitamin C reaction was verified by using Mn(III)-tetrakis(1-methyl-4-pyridyl)porphorin pentachloride as nitroxyl scavenger. The NOMela-dependent inactivation of GAPDH was so effective that this reaction can be used to quantify NOMela with high sensitivity.
Collapse
|
48
|
Improvement of the cold storage of blood vessels with a vascular preservation solution. Study in porcine aortic segments. J Vasc Surg 2008; 47:422-31. [DOI: 10.1016/j.jvs.2007.09.048] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 09/17/2007] [Accepted: 09/23/2007] [Indexed: 10/22/2022]
|
49
|
Dependence of product formation from decomposition of nitroso-dithiols on the degree of nitrosation. Evidence that dinitroso-dithiothreitol acts solely as an nitric oxide releasing compound. Org Biomol Chem 2008; 6:2560-73. [DOI: 10.1039/b801583j] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
50
|
|