Cold-induced injury to lung epithelial cells can be inhibited by iron chelators — implications for lung preservation

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 3 h). 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 24 h, 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.     

Nicardipine reverses vasoactivity associated with University of Wisconsin solution in the rat peripheral circulation

Background

The rapid uniform delivery of University of Wisconsin solution (UW) to the microcirculation may be compromised by its vasoactivity.

Methods

In 2 different rodent models, we tested whether UW-mediated vasoconstriction could be reversed with nicardipine.

Results

In the perfused, splanchnic circulation, intravascular control solutions (lactated Ringers [LR], Hextend [HEX], histidine-tryptophan-ketoglutarate [HTK]) or UW (± nicardipine) evoked pressure changes in 3 protocols (series 1; n = 35). In the cremaster muscle, topical control solutions or UW (± nicardipine) evoked vascular responses measured by video microscopy in 4 protocols (series 2; n = 47). In series 1A, 37°C UW increased perfusion pressure, but there was no change caused by LR, HEX, or HTK. In series 1B, 4°C UW caused a similar, albeit transient, increase. In series 1C, nicardipine reversed 37°C UW-mediated vasoconstriction in a dose-related manner. In series 2A, UW caused a 30%–59% constriction that varied with arteriolar branching order. In series 2B, the recovery from UW-induced vasoconstriction varied with duration of exposure, but nicardipine fully reversed residual vasoconstriction. In series 2C, cold and warm UW were equipotent, near maximal, vasoconstrictors. In series 2D, UW potentiated no-reflow.

Conclusion

UW causes a potent temperature-independent vasoconstriction by a calcium-mediated mechanism and this effect can be mitigated with nicardipine.     

Effect of different preservation solutions on adenine nucleotide content and metabolism in human kidney transplantation

Differences in purine metabolism produced by three preservation solutions were studied by determining the adenine nucleotide (ATP, ADP, AMP, and IMP) and nucleoside (adenosine, inosine, and hypoxanthine) levels in human kidney cortical biopsies. Forty kidney allografts were studied using University of Wisconsin (UW) solution (n=20), Euro-Collins (EC) solution (n=12), and modified EC solution with mannitol (M;n=8). No significant differences were found between the three solutions studied with regard to ATP, ADP, or AMP changes. The mean ATP level (nmol/mg prot±SEM) at the end of preservation in the UW group was 2.7±0.3 nmol/mg, in the EC group 3.8±0.7 nmol/mg, and in the M group 2.3±0.4 nmol/mg. ATP 30 min after reperfusion in the UW, EC, and M groups was 5.7±0.8 nmol/mg, 6.4±1.0 nmol/mg, and 4.6±0.5 nmol/mg, respectively. However, an important difference appeared in the catabolic products determined. Kidneys perfused with UW solution had a significantly higher level of adenosine (2.6±0.6 nmol/mg), inosine (11.8±2.2 nmol/mg), and hypoxanthine (18.1±2.1 nmol/mg) at hypoxanthine of cold storage than those perfused with EC (0.4±0.1 nmol/mg, 2.0±0.8 nmol/mg, and 7.1±1.4 nmol/mg) and M solutions (0.2±0.05 nmol/mg, 0.5±0.1 nmol/mg, and 5.2±0.6 nmol/mg; P<0.05). These levels returned to initial values 30 min postreperfusion and there were no differences with the EC or M solution groups at that time. Thus, the adenosine present in UW solution does not appear to be useful in recovering the adenine nucleotide pool at reperfusion. Moreover, it produces a marked increase in degradation products. Our findings do not support the beneficial metabolic effect of UW solution in terms of adenine nucleotide metabolism in comparison with simpler and less expensive preservation solutions like EC.     

Comparison between Perfadex and locally manufactured low-potassium dextran solution for pulmonary preservation in an ex vivo isolated lung perfusion model

Introduction

Lung tranplantation, a consolidated treatment for end-stage lung disease, utilizes preservation solutions, such as low potassium dextran (LPD), to mitigate ischemia-reperfusion injury. We sought the local development of LPD solutions in an attempt to facilitate access and enhance usage. We also sought to evaluate the effectiveness of a locally manufactured LPD solution in a rat model of ex vivo lung perfusion.

Methods

We randomized the following groups \?\adult of male Wistar rats (n = 25 each): Perfadex (LPD; Vitrolife, Sweden); locally manufactured LPD-glucose (LPDnac) (Farmoterapica, Brazil), and normal saline solution (SAL) with 3 ischemic times (6, 12, and 24 hours). The harvested heart-lung blocks were flushed with solution at 4°C. After storage, the blocks were connected to an IL-2 Isolated Perfused Rat or Guinea Pig Lung System (Harvard Apparatus) and reperfused with homologous blood for 60 minutes. Respiratory mechanics, pulmonary artery pressure, perfusate blood gas analysis, and lung weight were measured at 10-minute intervals. Comparisons between groups and among ischemic times were performed using analysis of variance with a 5% level of significance.

Results

Lungs preserved for 24 hours were nonviable and therefore excluded from the analysis. Those preserved for 6 hours showed better ventilatory mechanics when compared with 12 hours. The oxygenation capacity was not different between lungs flushed with LPD or LPDnac, regardless of the ischemic time. SAL lungs showed higher Pco₂ values than the other solutions. Lung weight increased over time during perfusion; however, there were no significant differences among the tested solutions (LPD, P = .23; LPDnac, P = .41; SAL, P = .26). We concluded that the LPDnac solution results in gas exchange were comparable to the original LPD (Perfadex); however ventilatory mechanics and edema formation were better with LPD, particularly among lungs undergoing 6 hours of cold ischemia.     

Comparison of University of Wisconsin and University of Pittsburgh solutions for heart transplantation

The effectiveness of University of Wisconsin (UW) and University of Pittsburgh (UP) solutions for the preservation of rat hearts was compared. Lewis rat hearts were preserved with UW (group A, n=45) or UP (group B, n=45) solution for 0 or 24 h and then transplanted heterotopically into the recipients' abdomen. Ten recipients in each group were observed to obtain 1-week graft survival rates. Tissue water content and tissue content of adenine nucleotides were measured 2 h after transplantation in six grafts from each group. Six hearts preserved for 0 h and seven hearts preserved for 24 h were taken from each group 24 h after grafting for histopathology. The 1-week graft survival rates of groups A24 and B24 were 60% and 10%, respectively. In the 24-h preserved grafts, adenosine triphosphate (ATP) and energy charge [(ATP+adenosine diphosphate/2)/(ATP+adenosine diphosphate+adenosine monophosphate)] of groups A and B were 0.972±0.165 and 0.200±0.123 mg/g wet tissue (P<0.05) and 74.4% and 61.1% (P<0.05), respectively. The tissue water content of group A24 was 71.7%, whereas that of group B24 was 74.1% (P<0.05). Histopathology revealed more severe muscle edema and necrosis and infiltration of polymorphonuclear cells in group B24 than in group A24. We conclude that UW solution is more appropriate for rat heart preservation than UP solution.     

An in vitro method for comparing the efficacy of two preservation solutions in one canine liver using the 5′-nucleotidase assay

The activity and localization of the plasma membrane-bound enzyme 5-nucleotidase (5-NT) in liver tissue are sensitive parameters of ischemic damage. The value of 5-NT as a marker of liver graft viability was studied in relation to liver preservation. In six mongrel dogs, the main right and left branches of the portal vein were cannulated and flushed separately in situ with cold University of Wisconsin (UW) solution and Euro-Collins (EC) solution, respectively. After hepatectomy, the right and left liver lobes were split and stored at 5°C in either of the two solutions. 5-NT activity was demonstrated in cryostat sections of liver tissue using the lead salt method. After 48 h of storage in EC solution, the 5-NT score had decreased to 31%±16% (n=6), whereas in UW solution the 5-NT score was 76%±10% (n=6). Significantly (P<0.05) higher 5-NT scores were also found after 24-h and 72-h preservation times in UW versus EC solutions. This result is in keeping with the higher preservation tolerance of liver grafts preserved in UW solution. The 5-NT assay was studied in relation to graft function in orthotopic liver transplantation experiments in dogs. All dogs with liver grafts preserved in UW solution for 24 h (n=4) and 48 h (n=3) survived (>5 days). pretransplant 5-NT scores ranged from 61% to 100%. The 72-h-preserved livers (n=5) did not show life-supporting function. Pretransplant 5-NT scores (33%±12%, n=5) were significantly (P<0.05) decreased. The 5-NT score pretransplantation was a more reliable indicator of graft function than peak SGOT values post-transplantation. In conclusion, the 5-NT assay, in conjunction with the double flush method through the portal vein, provides a simple and rapid in vitro method to test solutions for liver preservation.     

Microcirculatory disturbances and leucocyte adherence in transplanted livers after cold storage in Euro-Collins,UW and HTK solutions

Integrity of the hepatic microcirculation and maintenance of endothelial cell viability are critical components in preventing primary non-function after liver transplantation. Therefore, hepatic microcirculation and leucocyte-endothelial interaction were studied in rat livers stored for 1 h in Euro-Collins (EC), University of Wisconsin (UW), and histidine-tryptophan-ketoglutarate (HTK) solutions and subsequently transplanted. One hour after transplantation surgery, the livers were exposed under an intravital fluorescence microscope. After injection of the leucocyte marker acridine orange (1 mol/kg), six pericentral fields were observed for 30 s and experiments were recorded continuously. The percentage of perfused sinusoids was reduced in the livers in the EC group (82.9%) in contrast to the UW (93.2%) and HTK groups (91.0%). Livers in the EC group showed a reduction in the diameters of pericentral sinusoids (7.3±0.2 m; mean±SEM) compared with the UW group (9.5±0.2 m; P<0.05) and HTK group (10.2±0.8 m; P<0.05), indicating substantial cell swelling in livers stored in EC solution. Permanent adherence of leucocytes was most frequently observed in the EC group (33.5±1%), while this phenomenon was less pronounced in the UW group (14.5+1.1%; P<0.05) and HTK group (16.3±0.7%; P<0.05). Conversely, temporary adherence of leucocytes was reduced in the EC group (19.7+1.3%) compared with the UW group (30.5+2.1%) and the HTK group (34.4+0.8%). Microcirculatory failure and cell swelling in the EC group might be due to the lack of osmotic substances or oxygen radical scavengers included in UW (allopurinol, glutathione) and HTK (mannitol) solutions. In conclusion, cold storage of livers in UW and HTK solutions results in better preservation of the microcirculation and prevention of adhesion of leucocytes after transplantation compared with the EC solution.     

Functional and biochemical evaluation of the preserved lung in a rat model

Lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) activities and total protein concentrations were examined in the postrinsing solutions from rat lungs preserved in phosphate-buffered saline (PBS), Euro-Collins (E-C) solution, or low-potassium E-C solution for 8 h at 4°C, 10°C, or 20°C. The LDH and AST activities were higher when the organs were preserved in PBS for 8 h at 20°C than at 4°C or 10°C, while the total protein concentration did not differ according to the temperature or solution. The activities were also higher when the lungs were preserved in Euro-Collins (E-C) solution than in PBS or the low-potassium E-C solution. On examining pulmonary functions utilizing an ex vivo reperfusion model, the lungs preserved at 20°C showed poorer gas exchange than those preserved at 4°C or 10°C. Moreover, the organs preserved in E-C solution showed poorer function than those preserved in any other solution. These findings suggest that some enzymatic activities in the postrinsing solution could be indicators of lung viability after preservation.     

Comparing the performance of rat lungs preserved for 6 or 12 hours after perfusion with low-potassium dextran or histidine-tryptophan-ketoglutarate

Introduction

In lung transplantation, graft dysfunction is a frequent cause of mortality; the etiopathogenesis is related to ischemia-reperfusion injury. We sought to compare the lung performance of rats after reperfusion after presentation with 3 solutions at 2 ischemia times.

Methods

We randomized 60 male Wistar rats to undergo anterograde perfusion via the pulmonary artery with low-potassium dextran (LPD), histidine-tryptophan ketoglutarate (HTK), or saline. After extraction, the heart-lung blocks were preserved in a solution at hypothermia for 6 or 12 hours before perfusion with homologous blood for 60 minutes using ex vivo system Isolated Perfused Rat or Guinea Pig Lung System (Harvard Apparatus). Respiratory mechanics, pulmonary weight, pulmonary artery pressure (PAP), and relative lung oxygenation capacity (ROC) measurements were obtained every 10 minutes.

Results

Comparing tidal volume (TV), compliance, resistance, ROC, PAP, and pulmonary weight the LPD, HTK, and saline group did not differ at 6 and 12 hours. The TV was higher in the lungs with 6-hour ischemia in the LPD, HTK, and saline groups. Compliance was higher in the lungs with 6-hour ischemia in the LPD and saline groups. There were no differences in ROC values comparing lungs with 6- versus 12-hour ischemia in the LPD group. A significant difference was observed between lungs in the HTK and saline groups. Resistance was higher in the lungs with 12-hour ischemia among the LPD, HTK, and saline groups. There was a gradual weight increase in the lungs, particularly those undergoing 12-hour ischemia, despite the absence of a significant difference between groups.

Conclusion

Rat lungs perfused with LPD and HTK preservation solutions showed similar reperfusion performances in this ex-vivo perfusion model.     

Inflammatory reactions after vascular prosthesis implantation: A comparison of gelatin-sealed and unsealed dacron prostheses

Despite widespread use of the gelatin-sealed knitted Dacron prosthesis (GDP) in clinical practice owing to its zero porosity, the biological impacts of this graft are still controversial. We conducted a randomized controlled study on 50 patients undergoing abdominal aortic aneurysm repair to evaluate the inflammatory reaction to GDP (n=25) and unsealed knitted Dacron prostheses (UDP, n=25). There were no significant differences in the mean age, size of the aneurysm, operative time, blood loss, or transfusion requirements between the GDP and UDP groups. During the first 7 postoperative days (PODs), slight fever and leukocytosis were noticed in both groups. Significant differences in maximum body temperature, leukocyte count, and plasma C-reactive protein concentration were observed between the GDP and VDP groups on POD 14: 37.2±0.5°C vs 36.9±0.3°C (P=0.019), 8,151±1,788/l vs 6,914±1,501/l (P=0.015), and 32.6±27.5mg/l vs 19.0±15.8mg/l (P=0.048), respectively. By POD 21, however, there were no detectable differences in these variables. Thus, we concluded that GDP caused an inflammatory reaction in the 2nd week after implantation, but ultimately there were no significant differences from UDP by the 3rd week.     

Evaluation of a new solution containg trehalose for twenty-hour canine lung preservation

We examined the efficacy of two new preservation solutions containing trehalose-an extracellular type (ET-K) of solution and an intracellular type (IT-K) of solution — in relation to that of Euro-Collins (EC) solution in 20-h canine lung preservation. Canine lungs were flushed with one of the three solutions (n=5 for each solution) after pretreatment with PGE₁ (20 g/kg) and were stored for 20 h at 4°C. The left lungs were transplanted and evaluated to 6 h post transplant. In the ET-K group, the arterial oxygen tension after reperfusion was significantly higher than in the IT-K and EC groups. The pulmonary vascular resistance, wet/dry weight ratio, and histological evaluation of each transplanted lung in the ET-K group were also better than in the IT-K and EC groups. This indicates that ET-K solution is useful for 20-h preservation of canine lung grafts.     

Measurement of the vasoconstrictive substances endothelin,angiotensin II,and thromboxane B2 in cold storage solution can reveal previous renal ischemic insults

In a rat model, the left kidney was subjected to 60 min of normothermic ischemia followed by 15 min of reperfusion, whereas the right kidney, serving as a paired control, was not rendered ischemic. Both kidneys were then perfused in situ with either Euro-Collins (EC) solution (n=12) or University of Wisconsin (UW) solution (n=6) for 10 min. Each kidney was then harvested and stored at 4°C in its respective solution. After 24 and 48 h of cold storage, the following vasoactive substances were measured in the preservation media: endothelin (ET), angiotensin II (A-II), thromboxane (B₂) (TxB₂), and prostaglandin I₂ (PGI₂). After 24 h in EC solution, left kidneys uniformly produced significantly higher concentrations of each vasoactive substance than right kidneys: ET 1.64±0.3 pg/ml vs 0.82±0.1 pg/ml (P0.009); A-II 20.8±6.2 pg/ml vs 7.75+2.3 pg/ml (P0.007); TxB₂ 100.8±17.7 pg/ml vs 40.1±11.7 pg/ml (P0.04); PGI₂ 638.3±41.1 pg/ml vs 318.3±36.4 pg/ml (P0.001), respectively. At 48 h, a similar pattern of results was obtained as the kidney continued to produce TxB₂ and prostacyclins during the 24–48 h period. In the UW solution, basal levels of ET and A-II were lower than those in EC solution, but similarly increased after initial ischemia. At 24 h, the concentrations produced by the left and right kidneys were as follows: ET 0.66±0.1 pg/ml vs 0.48±0.1 pg/ml (P0.14); A-II 10.36±3.7 pg/ml vs 2.14±0.7 pg/ml (P0.006); TxB₂ 178±53 pg/ml vs 52±23.1 pg/ml (P0.001); and PGI₂ 448.3±49 pg/ml vs 323±44.3 pg/ml (P0.01), respectively. After 48 h, the range of concentrations of each substance was similar to that obtained after 24 h. In further studies, the concentrations of ET and A-II were measured in solution previously used to preserve human kidneys (n=7). The mean concentration of ET and A-II in these samples was 3.82±1.14 pg/ml and 21.3±9.2 pg/ml, respectively, whereas in control media both substances were below the limits of detection. These results demonstrate that vasoconstrictive substances can be measured in the preservation media after a kidney has been stored cold and that higher concentrations are found when the organ has been subjected to prior normothermic ischemia. The measurement of these vasoactive substances before transplantation may reveal that the kidney has been subjected to previous ischemic events. Moreover, these vasoactive substances could be involved in the early recovery of renal function after kidney transplantation.     

A retrospective 12-month study of conversion to everolimus in lung transplant recipients

Background

Everolimus has potent antifibrotic effects that may potentially affect the clinical course of bronchiolitis obliterans syndrome (BOS) or provide nephroprotective immunosuppressive regimens for lung transplantation.

Methods

We retrospectively assessed the 12-month outcomes of the conversion to everolimus among lung recipients in six Spanish centers.

Results

From March 2005 to December 2007, 65 lung recipients who were at a mean posttransplantation time of 10.2 ± 7.9 months were converted to everolimus, mainly because of BOS (64.6%) or renal insufficiency (RI; 12.3%). The initial dose of everolimus was 1.9 ± 0.6 mg/d and the mean blood trough levels were stable over time (6.4 ± 2.8 ng/mL at 12 months). Conversion to everolimus allowed us to eliminate the calcineurin inhibitor (CNI) in 21% of patients. Among the overall population, the forced expiratory volume at 1 second (FEV₁) and renal function remained stable. Mean FEV₁ did not change among the 35 (81%) patients surviving BOS at 12 months: preconversion FEV₁: 1.449.5 ± 641.9 mL vs 12-month FEV₁: 1420.0 ± 734.6 mL (P = .866). There was a significant improvement in renal function among the RI patients with mean glomerular filtration rates of 42.2 ± 15.2 mL/min/1.73 m² (P = .043) at 6 and 44.4 ± 18.8 mL/min/1.73 m² at 12 months, (P = .063) and a decrease in the use of CNIs from 1% of RI patients preconversion to 57% at 6 and 75% at 12 months. With a mean of 8.1- months follow-up (range: 1–31.3) overall survival was 84.6% at 1 year and 50% at 22.3 months. Progressive BOS was the main cause of death. Reasons for everolimus discontinuation were patient death (n = 10), lack of efficacy (n = 4), gastrointestinal adverse events (n = 2), and edema (n = 2).

Conclusions

BOS and RI were the main indications for conversion to everolimus among lung recipients. Conversion to everolimus improved renal function among patients converted because of RI. The present results were inconclusive regarding effects of everolimus on BOS.     

Safety and beneficial effect on body core temperature of a prewarmed plasma substitute—hydroxyethyl starch—during anesthesia

Purpose We investigated, first, the safety of use and stability of a plasma substitute—hydroxyethyl starch (HES)—kept in a warming cabinet for a long period, and then the effect on body core temperature of the prewarmed HES in patients during urological surgery.Methods In the first part of the study, HES colloid solutions (500ml per pack; Hespander) were kept in a warming cabinet (40°C) for 3 months and were tested for biological and chemical safety and stability. In the second part of the study, 1000ml of HES at room temperature (control group; n = 10) or kept in a warming cabinet for a few days (warmed group; n = 10) was infused via a central venous catheter for 30min in patients undergoing urological surgery under general anesthesia with lumbar epidural anesthesia. Esophageal temperature was monitored as the core temperature. HES fluid temperatures in the pack and at the end of a 1-m intravenous tube connected to the central venous catheter were also measured.Results The test of HES products warmed for 3 months passed all inspections performed during the study period. In the warmed group, the pack and intravenous tube temperatures of HES were still high at 15min after infusion (37.1° ± 1.5°C [mean ± SD] and 34.8° ± 2.2°C, respectively). Core temperature in the warmed group decreased significantly, by 0.34° ± 0.06°C, but was significantly higher than that in the control group (by 0.84° ± 0.13°C) after 30min of the infusion.Conclusions The use of HES products kept in a warming cabinet prior to surgery can maintain warm body temperature, easily, safely, and effectively.     

Long-term preservation of the pig pancreas by a one-layer method for successful islet isolation

Background

Pancreas preservation by two-layer method (TLM) was recently established for clinical islet transplantation. The extensive use of TLM would require enormous efforts to solve logistical and technical problems. Omitting University of Wisconsin solution (UW) as second layer would facilitate the regular application of oxygenated perfluorocarbon; (PFC). To clarify whether long-term pancreas preservation is feasible by this simplified procedure, pancreases from retired breeder pigs were subjected to 7-hour preservation utilizing PFC alone in a one-layer method (OLM, n = 8) or in combination with UW (TLM, n = 10).

Methods

Resected pancreata were intraductally flushed with cold UW. Subsequently, pancreata were promptly processed (n = 6) as previously described or stored by TLM or OLM.

Results

Compared to unstored (429200 ± 86700 IEQ) and OLM-stored pancreases (338600 ± 42100 IEQ), (P = ns vs unstored) postpurification islet yield decreased after TLM storage (238000 ± 26600 IEQ, P < .05). No significant differences were found regarding purity (>90%), adenosine triphosphate (ATP) content, and viability as determined by formazan production and trypan-blue exclusion (>95%). Glucose stimulation index of freshly isolated islets (2.5 ± 0.4) was significantly decreased after TLM storage (1.8 ± 0.2, P < .05) but not after OLM storage (2.3 ± 0.6). Islet transplantation in diabetic nude mice demonstrated sustained graft function in all experimental groups.

Conclusions

This study demonstrates that viable pig islets can be successfully isolated after prolonged ischemia utilizing PFC alone for oxygenation of cold-stored pig pancreases. The easy handling of OLM could facilitate the regular application of PFC as pancreas preservation solution.     

The effect of PGE1 and temperature on lung function following preservation.

We studied the effect of a vasodilator (prostaglandin E1) as well as flush (F) and storage (S) temperatures (4 degrees C or 10 degrees C) on lung preservation in an isolated rabbit lung perfusion model. Low-potassium dextran (LPD) or Euro-Collins (E-C) solution was used as flush solution. Six groups of six animals were studied: group 1 (LPD, 4 degrees C F-S), group 2 (LPD with PGE1, 4 degrees C F-S), group 3 (E-C with PGE1, 4 degrees C F-S), group 4 (LPD, 10 degrees C F-S), group 5 (LPD with PGE1, 10 degrees C F-S), group 6 (E-C with PGE1, 10 degrees C F-S). After 18-hr preservation, left lungs alone were ventilated, and reperfused with fresh venous blood. PaO2, PaCO2, pulmonary artery pressure (PAP), tracheal pressure (Pt) during reperfusion, and wet/dry weight (W/D) ratios were measured. PaO2 after LPD with or without PGE1 was significantly higher than after E-C with PGE1 at 4 degrees C (95.8 +/- 11.5 mmHg in group 1 or 102.7 +/- 8.6 in group 2 vs. 41.8 +/- 10.5 in group 3, P less than 0.01) and at 10 degrees C (119.3 +/- 2.3 in group 4 or 131.1 +/- 6.2 in group 5 vs. 54.6 +/- 5.2 in group 6, P less than 0.01). PaCO2, PAP, Pt, and W/D ratios in the LPD groups were lower than in the E-C groups. LPD/PGE1 and LPD alone produced similar pulmonary preservation. PaO2 of lungs flushed with LPD and preserved at 10 degrees C was higher than that of lungs stored at 4 degrees C. We conclude that LPD solution is superior to E-C solution in this ex vivo rabbit lung preservation model, even when PGE1 is used. A moderate dose of PGE1 did not improve the performance of LPD as a flush solution. Pulmonary preservation with LPD at 10 degrees C is superior to preservation at 4 degrees C.     

Extracorporeal cisplatin removal using direct hemoperfusion under hepatic venous isolation for hepatic arterial chemotherapy: An experimental study on pharmacokinetics

This study was undertaken to pharmacokinetically evaluate the efficacy of direct hemoperfusion under hepatic venous isolation (HVI-DHP) to cisplatin (CDDP) removal during hepatic arterial infusion. CDDP (2–4 mg/kg) was administered continuously to mongrel dogs through the hepatic artery for 10 min. Plasma levels and tissue concentrations were then compared between animals receiving CDDP alone (group 1, n=4) and those treated with additional HVI-DHP for 20 min (group 2, n=6). The peak CDDP levels in the right external jugular vein (systemic level) were 6.10±1.31 (mean±SD) and 1.41±0.12 g/ml in groups 1 and 2 at a dosage of 2 mg/kg, respectively (P<0.01). The estimated drug removal rates in group 2 animals at dosages of 2 and 4 mg/kg were 45.7 (mean, n=5) and 46.9% (n=1), respectively. The tissue concentrations of CDDP of the liver 30 min after the initiation of infusions were similar in both groups. The values of the liver, the heart, and the kidney were 1.90±0.55, 0.50±0.16, and 3.90±2.50 g/g of wet tissue weight, respectively, in group 1. In contrast, tissue levels of the heart and the kidney in group 2 animals were significantly reduced, with the values at a dosage of 2 mg/kg being 0.21±0.03 g/g (P<0.01) and 0.86±0.53 g/g (P<0.05), respectively. This study demonstrated that the extrahepatic distribution of CDDP during hepatic arterial infusion can be reduced significantly by the concomitant use of HVI-DHP.     

Prevention of postischemic reperfusion injury: The improvement of myocardial tissue blood flow after ischemia by terminal Nicorandil-Mg cardioplegia

We evaluated the preventive effect of postischemic reperfusion injury by Nicorandil-Mg cardioplegia given just prior to reperfusion as terminal cardioplegia. Twenty seven dogs were placed on cardiopulmonary bypass and the aorta was cross-clamped for 90 min under hypothermic (17–19°C) cardioplegic arrest. The canine hearts were divided into three groups: in group A (n=10) the hearts were reperfused without any treatment; in group B (n=9) the hearts received coronary perfusion with Nicorandil-Mg solution (Nic, 8 mg/l; Mg, 20 mEq/l; glucose, 50 g/l) for 2 min just prior to reperfusion; and in group C (n=8) the hearts received coronary perfusion with Nicorandil-Mg free solution (glucose, 50g/l). During and after ischemia, the myocardial tissue PCO₂ (t-PCO₂) was continuously monitored by an ion-sensitive field effective transistor (ISFET) sensor. In addition, the myocardial tissue blood flow (TBF), oxygen consumption, and lactate flux were then calculated at 5, 10, 20, and 40 min of reperfusion. In the initial reperfusion period, Group B showed an improved TBF compared to group A and C (at 5 min, group B was 42.7±11.9; group A was 29.4±11.2, P<0.025; and group C was 33.9±9.2% of the preischemic control level, P<0.05). T-PCO₂ in group B was significantly decreased at 5 min of reperfusion (group B, 127.5±22.5 42.5±9.7; group A, 117.5±23.0 85.2±17.4, P<0.001; group C, 122.3 mmHg 68.2±18.7 mmHg, P<0.01), and group B had a better metabolic recovery. These results suggest that terminal Nicorandil-Mg cardioplegia might reduce the rate of postischemic reperfusion injury.     

Jugular Venous Oxygen Saturation During Mild Hypothermic Versus Normothermic Cardiopulmonary Bypass in Elderly Patients

Purpose. Age is known to be a major risk factor for adverse postoperative cognitive dysfunction after cardiac surgery. We conducted this study to determine if jugular venous oxygen saturation (SjvO₂) differed during mild hypothermic (32°C) and normothermic cardiopulmonary bypass (CPB) in elderly patients.Methods. Sixty patients aged over 70 years who underwent elective coronary artery bypass grafting were randomly divided into two groups. Group 1 (n = 30) underwent normothermic CPB (>35°C) and group 2 (n = 30) underwent mild hypothermic CPB (32°C). For the continuous monitoring of SjvO₂, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb after the induction of anesthesia. Hemodynamic parameters, and arterial and jugular venous blood gases were measured at seven time points.Results. The SjvO₂ in the normothermic group was lower at the onset of CPB and 20min after the onset, than from the time of induction of anesthesia until the start of surgery (period 1), the respective SjvO₂ values being 50.3% ± 1.0%, 50.1% ± 1.6%, and 59.5% ± 1.9% (P < 0.05). However, in the mild hypothermic group there were no changes in the SjvO₂ value throughout the study. The cerebral desaturation time (when the SjvO₂ value was <50%) and the ratio of the cerebral desaturation time to the total CPB time in the normothermic group differed significantly from those in the hypothermic group, being 19 ± 11min and 17% ± 10%, and 9 ± 3min and 8% ± 4%, respectively (P < 0.05).Conclusions. The SjvO₂ value was better during mild hypothermic CPB than during normothermic CPB in elderly patients.     

315. Wertigkeit der Endotoxinbestimmung beim Gram-negativen hyperdynamen septischen Schock

Zusammenfassung Pankreasgangocclusion mit Ethibloc wurde in folgenden Gruppen durchgeführt: durch Duodenotomie (n = 8), Wirsungianotomie (n = 8), Pankreassegmenttransplantation (n = 6). Elektromagnetische Flowmessungen (n = 12) wurden vor und nach Occlusion vorgenommen. Unmittelbar vor und nach Occlusion kam es zu keiner wesentlichen Durchblutungsänderung (23,0 ± 7,4 ml vs. 27,2 ± 18,5 ml) nach 6 Wochen war die Durchblutung auf 6,08 ml (± 2,75 ml) zurückgegangen (P 0,001). Die Langerhansschen Zellen blieben intakt und die Tiere normoglykämisch (i.v. GTT, stimuliertes Insulin).