Comparing the effects of Dextran 70 and Hydroxyethyl starch in an intestinal storage solution

Introduction

Our lab has developed a novel strategy for intestinal preservation involving the intraluminal delivery of a nutrient-rich preservation solution. The aim of this study was to compare the effectiveness of two impermeant agents for use in our solution: Dextran 70 (D70; Mw = 70 kDa) and Hydroxyethyl starch (HES; Mw = 2200 kDa).

Methods

Rat intestines were procured, including an intravascular flush with University of Wisconsin solution followed by a ‘backtable’ intraluminal flush with: UW solution (group 1, UW), or an amino acid-based nutrient-rich preservation solution (AA solution) containing either 5% D70 (group 2, AA-D70) or HES (group 3, AA-HES). Tissue samples (n = 6) were taken at 2, 4, 8, and 12 h cold storage; histology, energetic, end-product, and oxidative parameters were assessed. In separate groups (n = 4), D70 and HES were fluorescently labeled with fluorescein isothiocyanate (FITC) in order to directly observe mucosal penetration of the starch and dextran.

Results

Over the 12 h storage time-course, direct visualization of the fluorescently labeled D70 showed penetration of the mucosal layer as early as 2 h and progressively continued to do so throughout the 12 h period. In contrast, HES did not cross the mucosal barrier and remained captive within the lumen. As time of storage progressed, grade of injury increased in all groups, however, at 4 and 12 h the AA-HES treated tissues exhibited significantly less injury compared to UW and AA-D70, P < 0.05. AA-HES group showed on moderate villus clefting (median grade 2; P < 0.05) while the AA-D70 group exhibited complete villus denudation (grade 4) and the UW group had extensive injury into the regenerative cryptal regions (grade 6). Metabolic parameters revealed a preferential maintenance of ATP and Energy Charge; increases in lactate, alanine and ammonium supported the involvement of aerobic and anaerobic pathways for energy production.

Conclusion

The results of this study challenge the idea that oncotic support is not a fundamental requirement of static organ storage. Furthermore, our data suggests that HES is an effective oncotic agent for use in our intraluminal nutrient-rich preservation solution, while Dextran 70 is not.     

Comparing the effects of Dextran 70 and Hydroxyethyl starch in an intestinal storage solution

IntroductionOur lab has developed a novel strategy for intestinal preservation involving the intraluminal delivery of a nutrient-rich preservation solution. The aim of this study was to compare the effectiveness of two impermeant agents for use in our solution: Dextran 70 (D70; Mw = 70 kDa) and Hydroxyethyl starch (HES; Mw = 2200 kDa).MethodsRat intestines were procured, including an intravascular flush with University of Wisconsin solution followed by a ‘backtable’ intraluminal flush with: UW solution (group 1, UW), or an amino acid-based nutrient-rich preservation solution (AA solution) containing either 5% D70 (group 2, AA-D70) or HES (group 3, AA-HES). Tissue samples (n = 6) were taken at 2, 4, 8, and 12 h cold storage; histology, energetic, end-product, and oxidative parameters were assessed. In separate groups (n = 4), D70 and HES were fluorescently labeled with fluorescein isothiocyanate (FITC) in order to directly observe mucosal penetration of the starch and dextran.ResultsOver the 12 h storage time-course, direct visualization of the fluorescently labeled D70 showed penetration of the mucosal layer as early as 2 h and progressively continued to do so throughout the 12 h period. In contrast, HES did not cross the mucosal barrier and remained captive within the lumen. As time of storage progressed, grade of injury increased in all groups, however, at 4 and 12 h the AA-HES treated tissues exhibited significantly less injury compared to UW and AA-D70, P < 0.05. AA-HES group showed on moderate villus clefting (median grade 2; P < 0.05) while the AA-D70 group exhibited complete villus denudation (grade 4) and the UW group had extensive injury into the regenerative cryptal regions (grade 6). Metabolic parameters revealed a preferential maintenance of ATP and Energy Charge; increases in lactate, alanine and ammonium supported the involvement of aerobic and anaerobic pathways for energy production.ConclusionThe results of this study challenge the idea that oncotic support is not a fundamental requirement of static organ storage. Furthermore, our data suggests that HES is an effective oncotic agent for use in our intraluminal nutrient-rich preservation solution, while Dextran 70 is not.     

Creatine-loading preserves intestinal barrier function during organ preservation

We have developed a novel, intraluminal preservation solution that is tailored to the metabolic requirements of the intestine. This organ-specific solution addresses many of the problems associated with low temperature organ storage including energy, oxidative and osmotic stresses. However, conservation of energy levels remains one of the most difficult obstacles to overcome due to the inherent sensitivity of the mucosa to ischemia. Creatine-loading has become a popular and scientifically proven method of augmenting energy reserves in athletes performing anaerobic burst work activities. We hypothesized that if we could develop a method that was able to augment cellular energy levels, the structure and function of the mucosa would be more effectively preserved. The purpose of this study was to determine if creatine-loading is a feasible and effective strategy for preserving the intestine.Our data indicate that creatine loading has significant impact on energy levels during storage with corresponding improvements in mucosal structure and function. Both of our rodent models, a) continuous perfusion for 4 h and b) a single flush with our intraluminal preservation solution supplemented with 50 mM creatine, demonstrated significant improvements in creatine phosphate, ATP, Energy Charge and ATP/AMP following cold storage (P < 0.05). Notably, after 10 h creatine phosphate was 324% greater in Creatine-treated tissues compared to Controls (P < 0.05). Preferential utilization of glutathione in the Creatine group was effective at controlling oxidative injury after 10 h storage (P < 0.05). Improvements in barrier function and electrophysiology with creatine-treatment reflected superior mucosal integrity after 10 h storage; Permeability and Transepithelial resistance measurements remained at fresh tissue values. This was in stark contrast to Control tissues in which permeability rose to >300% of fresh tissue values (P < 0.005) and transepithelial resistance dropped by 95% (P < 0.005). After 10 h storage, Park's grading of histologic injury reflected extensive villus denudation (grade 4) in control tissues compared to healthy tissue (grade 0) in the Creatine group. This study demonstrates that a strategy of creatine supplementation of our intraluminal preservation solution facilitates the preservation of the intestinal mucosa during storage.     

Contractile and morphological properties of hamster retractor muscle following 16 h of cold preservation

Introduction

Cold hypoxia is a common factor in cold tissue preservation and mammalian hibernation. The purpose of this study was to determine the effects of cold preservation on the function of the retractor (RET) muscle of the hamster in the non-hibernating state and compare these with previously published data (van der Heijden et al., 2000) [52] on the rat cutaneus trunci (CT) muscle.

Materials and methods

After cold storage (16 h at 4 °C), muscles were stimulated electrically to measure maximum tetanus tension (P₀) and histologically analyzed. The protective effects of addition of the antioxidants trolox and deferiprone and the calcium release inhibitor BDM to the storage fluid were determined.

Results

After storage, the twitch threshold current was increased (from 60 to 500 μA) and P₀ was decreased to 27% of control. RET morphology remained unaffected. RET muscle function was protected by trolox and deferiprone (P₀, resp., 43% and 59% of control). Addition of BDM had no effect on the RET.

Conclusions

The observed effects of cold preservation and of trolox and deferiprone on the RET were comparable to those on CT muscle function, as reported in a previously published study (van der Heijden et al., 2000) [52]. Both hamster RET and rat CT muscles show considerable functional damage due to actions of reactive oxygen species. In contrast to the CT, in the RET cold preservation-induced functional injury could not be prevented by BDM and was not accompanied by morphological damage such as necrosis and edema. This suggests that the RET myocytes possess a specific adaptation to withstand the Ca²⁺ overload induced by cold ischemia.     

Beneficial effects of supplemental buffer and substrate on energy metabolism during small bowel storage

Successful preservation of small bowel (SB) is closely correlated with the maintenance of cellular energetics. This study was designed to assess the ability of a modified UW solution supplemented with buffer and glucose to facilitate ATP production during cold storage. In part A, rats SB (n = 4) were flushed vascularly as follows: Group 1, UW solution (control); Group 2, HUW solution (UW+90 mM histidine). Inclusion of histidine resulted in a >3-fold increase in buffering capacity over the pH range 7.4-6.8. Positive effects of histidine on ATP and energy charge were apparent after 4-10h storage. Examination of the key regulatory enzyme, Phosphofructokinase (PFK), reflected a sustained activation was over 1-4h in the HUW group only. In part B, groups were vascularly flushed as follows: Group 1, HUW solution (control); Group 2, Group 1+20mM glucose; and Group 3, Group 2+luminal flush. Elevated ATP and total adenylates over 2-10h in Group 3 compared to control were a direct consequence of improved glycolytic activity. This data supports the hypothesis that tissue energetics can be significantly improved during cold storage using a histidine-buffered UW solution supplemented with carbohydrate substrate.     

Dopamine improves hypothermic machine preservation of the liver

Background

Hypothermic machine preservation (HMP) is currently reconsidered as alternative to standard cold storage of organs from non-heart-beating donors. The present study was aimed at investigating the possible synergistic effect of HMP and the addition of dopamine to the circulating perfusate during preservation.

Methods

Cardiac arrest was induced in male Wistar rats (250–300 g) by phrenotomy. Thirty minutes later livers were flushed via the portal vein and subjected to 20 h of HMP at 5 ml/min at 4 °C. During HMP the preservation solution was equilibrated with 100% oxygen and dopamine was added at 0, 10, 50 or 100 μM (D0, D10, D50, D100; n = 6 resp.). Graft viability was assessed thereafter upon warm reperfusion in vitro for 2 h.

Results

During HMP, D50 and D100 significantly reduced hepatic release of ALT to about 50%. No influence of dopamine was found on vascular resistance, oxygen uptake or lactate production at any concentration. D50 significantly reduced enzyme release during reperfusion (∼50%), enhanced bile flow and oxygen consumption. D10 was less effective while D100 even rose enzyme release compared with D0.Enhanced oxygen free radical mediated lipid peroxidation (LPO), found in the tissue of D0 livers was significantly reduced by D50; D50 significantly abrogated molecular upregulation of vWillebrand factor upon reperfusion suggesting vascular protection of the endothelial cell.

Conclusion

Efficiency of HMP might be increased by stimulating livers with dopamine during ex vivo preservation, limiting vascular side effects and improving functional recovery upon early reperfusion.     

The influence of storage temperature during machine perfusion on preservation quality of marginal donor livers

Background

Although non-heart-beating donors have the potential to increase the number of available organs, the livers are used very seldom because of the risk of primary non-function. There is evidence that machine perfusion is able to improve the preservation of marginal organs, and therefore we evaluated in our study the influence of the perfusate temperature during oxygenated machine perfusion on the graft quality.

Methods

Livers from male Wistar rats were harvested after 60-min warm ischemia induced by cardiac arrest. The portal vein was cannulated and the liver flushed with Lifor® (Lifeblood Medical, Inc.) organ preservation solution for oxygenated machine perfusion (MP) at 4, 12 or 21 °C. Other livers were flushed with HTK and stored at 4 °C by conventional cold storage (4 °C-CS). Furthermore two groups with either warm ischemic damage only or without any ischemic damage serve as control groups. After 6 h of either machine perfusion or cold storage all livers were normothermic reperfused with Krebs–Henseleit buffer, and functional as well as structural data were analyzed.

Results

Contrary to livers stored by static cold storage, machine perfused livers showed independently of the perfusate temperature a significantly decreased enzyme release of hepatic transaminases (ALT) during isolated reperfusion. Increasing the machine perfusion temperature to 21 °C resulted in a marked reduction of portal venous resistance and an increased bile production.

Conclusions

Oxygenated machine perfusion improves viability of livers after prolonged warm ischemic damage. Elevated perfusion temperature of 21 °C reconstitutes the hepatic functional capacity better than perfusion at 4 or 12 °C.     

Cold storage of rat hepatocyte suspensions for one week in a customized cold storage solution--preservation of cell attachment and metabolism

Background & Aims

Primary hepatocytes are of great importance for basic research as well as cell transplantation. However, their stability, especially in suspension, is very low. This feature severely compromises storage and shipment. Based on previous studies with adherent cells, we here assessed cold storage injury in rat hepatocyte suspensions and aimed to find a cold storage solution that preserves viability, attachment ability and functionality of these cells.

Methods

Rat hepatocyte suspensions were stored in cell culture medium, organ preservation solutions and modified TiProtec solutions at 4°C for one week. Viability and cell volume were determined by flow cytometry. Thereafter, cells were seeded and density and metabolic capacity (reductive metabolism, forskolin-induced glucose release, urea production) of adherent cells were assessed.

Results

Cold storage injury in hepatocyte suspensions became evident as cell death occurring during cold storage or rewarming or as loss of attachment ability. Cell death during cold storage was not dependent on cell swelling and was almost completely inhibited in the presence of glycine and L-alanine. Cell attachment could be greatly improved by use of chloride-poor solutions and addition of iron chelators. Using a chloride-poor, potassium-rich storage solution containing glycine, alanine and iron chelators, cultures with 75% of the density of control cultures and with practically normal cell metabolism could be obtained after one week of cold storage.

Conclusion

In the solution presented here, cold storage injury of hepatocyte suspensions, differing from that of adherent hepatocytes, was effectively inhibited. The components which acted on the different injurious processes were identified.     

The influence of short-term fasting on the quality of small bowel graft preservation

INTRODUCTION: Donor nutritional status may be a determinant of small bowel (SB) quality following storage. In this study, we investigated the effect of donor nutritional status and a proven nutrient-rich preservation solution on graft quality following cold storage. METHODS: Rats were fasted (12-14 h) or non-fasted. SB (n=6) was flushed vascularly with modified University of Wisconsin (UW) solution and flushed luminally with UW or an amino acid-rich (AA) solution as follows: Fasted. UWV, none; UWL, UW solution; AAL, AA solution. Non-fasted. UWV, none; UWL, UW solution; AAL, AA solution. Energetics, peroxidation (malondialdehyde; MDA), glutathione and histology were assessed over 24 h at 4 degrees C. RESULTS: Energetics (ATP, ATP/ADP, and energy charge) were significantly higher in AAL (fasted and non-fasted) groups than other groups. However, there were no differences in energetics parameters between fasted and non-fasted animals in all groups. MDA was higher in fasted groups than non-fasted tissues; interestingly, AAL values were up to 10-fold lower than other groups. Higher glutathione levels were detected in non-fasted AAL tissues. Mucosal integrity was markedly superior in luminally treated tissues (UWL and AAL) in fasted and non-fasted states. Most noteably, AAL tissues from fasted animals exhibited grade 2 injury (villus clefting), whereas normal mucosa was observed in non-fasted tissues (grade 0). CONCLUSION: Luminal flushing and a nutrient-rich preservation solution improve energetics, oxidative stress, and mucosal integrity during storage. Poorer donor nutritional status does not affect energetics throughout storage, but causes mucosal injury as a result of increased oxidative stress, even after a brief period of donor fasting.     

Single injection recombinant vesicular stomatitis virus vaccines protect ferrets against lethal Nipah virus disease

Background

Nipah virus (NiV) is a highly pathogenic zoonotic agent in the family Paramyxoviridae that is maintained in nature by bats. Outbreaks have occurred in Malaysia, Singapore, India, and Bangladesh and have been associated with 40 to 75% case fatality rates. There are currently no vaccines or postexposure treatments licensed for combating human NiV infection.

Methods and results

Four groups of ferrets received a single vaccination with different recombinant vesicular stomatitis virus vectors expressing: Group 1, control with no glycoprotein; Group 2, the NiV fusion protein (F); Group 3, the NiV attachment protein (G); and Group 4, a combination of the NiV F and G proteins. Animals were challenged intranasally with NiV 28 days after vaccination. Control ferrets in Group 1 showed characteristic clinical signs of NiV disease including respiratory distress, neurological disorders, viral load in blood and tissues, and gross lesions and antigen in target tissues; all animals in this group succumbed to infection by day 8. Importantly, all specifically vaccinated ferrets in Groups 2-4 showed no evidence of clinical illness and survived challenged. All animals in these groups developed anti-NiV F and/or G IgG and neutralizing antibody titers. While NiV RNA was detected in blood at day 6 post challenge in animals from Groups 2-4, the levels were orders of magnitude lower than animals from control Group 1.

Conclusions

These data show protective efficacy against NiV in a relevant model of human infection. Further development of this technology has the potential to yield effective single injection vaccines for NiV infection.

     

Poly(ADP-ribose) polymerase-1 protects from oxidative stress induced endothelial dysfunction

Background

Generation of reactive oxygen species (ROS) is a key feature of vascular disease. Activation of the nuclear enzyme poly (adenosine diphosphate [ADP]-ribose) polymerase-1 (PARP-1) is a downstream effector of oxidative stress.

Methods

PARP-1(−/−) and PARP-1(+/+) mice were injected with paraquat (PQ; 10 mg/kg i.p.) to induce intracellular oxidative stress. Aortic rings were suspended in organ chambers for isometric tension recording to analyze vascular function.

Results

PQ treatment markedly impaired endothelium-dependent relaxations to acetylcholine in PARP-1(−/−), but not PARP-1(+/+) mice (p < 0.0001). Maximal relaxation was 45% in PQ treated PARP-1(−/−) mice compared to 79% in PARP-1(+/+) mice. In contrast, endothelium-independent relaxations to sodium nitroprusside (SNP) were not altered. After PQ treatment, l-NAME enhanced contractions to norepinephrine by 2.0-fold in PARP-1(−/−) mice, and those to acetylcholine by 3.3-fold, respectively, as compared to PARP-1(+/+) mice. PEG-superoxide dismutase (SOD) and PEG-catalase prevented the effect of PQ on endothelium-dependent relaxations to acetylcholine in PARP-1(−/−) mice (p < 0.001 vs. PQ treated PARP-1(+/+) mice. Indomethacin restored endothelium-dependent relaxations to acetylcholine in PQ treated PARP-1(−/−) mice (p < 0.05 vs. PQ treated PARP-1(+/+).

Conclusion

PARP-1 protects from acute intracellular oxidative stress induced endothelial dysfunction by inhibiting ROS induced production of vasoconstrictor prostanoids.     

Warm Ischemic Injury Is Reflected in the Release of Injury Markers during Cold Preservation of the Human Liver

Background

Liver transplantation plays a pivotal role in the treatment of patients with end-stage liver disease. Despite excellent outcomes, the field is strained by a severe shortage of viable liver grafts. To meet high demands, attempts are made to increase the use of suboptimal livers by both pretransplant recovery and assessment of donor livers. Here we aim to assess hepatic injury in the measurement of routine markers in the post-ischemic flush effluent of discarded human liver with a wide warm ischemic range.

Methods

Six human livers discarded for transplantation with variable warm and cold ischemia times were flushed at the end of preservation. The liver grafts were flushed with NaCl or Lactated Ringer’s, 2 L through the portal vein and 1 L through the hepatic artery. The vena caval effluent was sampled and analyzed for biochemical markers of injury; lactate dehydrogenase (LDH), alanine transaminase (ALT), and alkaline phosphatase (ALP). Liver tissue biopsies were analyzed for ATP content and histologically (H&E) examined.

Results

The duration of warm ischemia in the six livers correlated significantly to the concentration of LDH, ALT, and ALP in the effluent from the portal vein flush. No correlation was found with cold ischemia time. Tissue ATP content at the end of preservation correlated very strongly with the concentration of ALP in the arterial effluent (P<0.0007, R² = 0.96).

Conclusion

Biochemical injury markers released during the cold preservation period were reflective of the duration of warm ischemic injury sustained prior to release of the markers, as well as the hepatic energy status. As such, assessment of the flush effluent at the end of cold preservation may be a useful tool in evaluating suboptimal livers prior to transplantation, particularly in situations with undeterminable ischemic durations.     

Effect of Hypotensive Resuscitation with a Novel Combination of Fluids in a Rabbit Model of Uncontrolled Hemorrhagic Shock

Objective

The aim of this study was to compare the effects of hypotensive and normotensive resuscitation with a novel combination of fluids via lactate Ringer’s solution (LRS), 6% hydroxyethyl starch 130/0.4 solution (HES), and 7.5% hypertonic saline solution (HSS) at early stage of uncontrolled hemorrhagic shock (UHS) before hemostasis.

Methods

New Zealand white rabbits (n = 32) underwent UHS by transecting the splenic parenchyma, followed by blood withdrawal via the femoral artery to target mean arterial pressure (MAP) of 40–45 mmHg. Animals were distributed randomly into 4 groups (n = 8): in group Sham, sham operation was performed; in group HS, UHS was untreated; in group HS-HR, UHS was treated by hypotensive resuscitation with HSS and LRS+HES (ratio of 2∶1) to MAP of 50–55 mmHg; in group HS-NR, UHS was treated by normotensive resuscitation with HSS and LRS+HES (ratio of 2∶1) to MAP of 75–80 mmHg. Outcomes of hemodynamics, inflammatory and oxidative response, and other metabolic variables were measured and the histopathological studies of heart, lung and kidney were performed at the end of resusucitation.

Results

Hypotensive resuscitation with the novel combination of fluids for UHS rabbits decreased blood loss, maintained better stabilization of hemodynamics, and resulted in relatively higher hematocrit and platelet count, superior outcomes of blood gas, and lower plasma lactate concentration. Besides, hypotensive resuscitation attenuated the inflammatory and oxidative response significantly in UHS rabbits.

Conclusion

Hypotensive resuscitation with the novel combination of fluids via HSS and LRS+HES (ratio of 2∶1) has an effective treatment at early stage of UHS before hemostasis.     

Characterisation of lactic acid producing <Emphasis Type="Italic">Sporolactobacillus</Emphasis> strains from tree barks in Thailand

Eight spore-forming lactic acid producing bacteria were isolated from tree barks in Thailand. They were identified as Sporolactobacillus nakayamae (Group I, three isolates), S. terrae (Group II, two isolates), S. kofuensis (Group III, one isolate) and S. inulinus (Group IV, two isolates) based on their phenotypic characteristics and 16S rRNA gene sequence analyses. Four isolates in Groups I and II produced DL lactic acid (89.60–114.61 g/L), while three isolates in Groups III and IV produced D-lactic acid (88.01–113.78 g/L). Isolate BK65-3 identified as S. inulinus produced the highest D-lactic acid concentrations (101.42 g/L), productivity (1.41 g/L/h), yields (84.52%) and optical purity of D-lactic acid (100%).     

Gaseous persufflation with carbon monoxide during ischemia protects the isolated liver and enhances energetic recovery

Background

The benefit of carbon monoxide as applied by controlled, continuous gaseous persufflation during liver preservation on postischemic graft recovery was investigated in an isolated rat liver model.

Methods

Livers from male Wistar rats were retrieved 30 min after cardiac arrest of the donor and subjected to 18 h of cold storage. Some grafts were subjected to gaseous persufflation with carbon monoxide (CO, dissolved in nitrogen) during static cold storage at a concentration of 50 ppm or 250 ppm. Graft viability was assessed thereafter upon warm reperfusion in vitro.

Results

CO-persufflation significantly reduced cellular enzyme loss (maximal at 50 ppm) and functional recovery (bile production and energy charge) upon reperfusion by about 50%. The effect was associated with a reduction of free radical-induced lipid peroxidation, lower vascular perfusion resistance, and improved mitochondrial ultrastructure.

Conclusion

Viability of cold stored liver grafts can be notably augmented by gaseous ex vivo application of low dose CO to the isolated organ.     

University of Wisconsin Solution with Trypsin Inhibitor Pefabloc Improves Survival of Viable Human and Primate Impure Islets During Storage

Background. Recent studies suggest that impure islets (islets which have not been isolated from exocrine tissue and other parts of the pancreas) have great potential for successful transplantation. The evidence that supports this view includes findings that embedded islets (islets surrounded by exocrine tissue) undergo less apoptosis, peripancreatic lymph nodes prevent recurrence of IDDM (insulin dependent diabetes mellitus), and that islet yields and insulin content decrease during the purification process. Improved protocols have also been developed to prevent allorejection of impure islets. Despite these promising results, the storage of impure islets remains difficult, and was a method sought to decrease storage losses. Methods. Storage methods of impure human and non-human primate islets were compared, using either culture media or University of Wisconsin solution (UW). The effects of trypsin inhibition using Pefabloc (Roche Molecular Biochemicals, Indianapolis, IN) during storage period were also examined. Results. Low temperature and inhibition of trypsin activity during storage of impure islets improved both islet yield and viability. It was found that using UW solution and trypsin inhibition allowed perfect preservation of viable impure islets up to 48h. A functional assay by glucose stimulation test showed these impure islet responded to glucose stimulation after 24h. Conclusion. The benefits of storing impure islets using UW solution and Pefabloc at low temperature have been established. This improved method of preserving impure islets makes this model of transplantation even more viable.     

Hyperbranched Polyglycerol as a Colloid in Cold Organ Preservation Solutions

Hydroxyethyl starch (HES) is a common colloid in organ preservation solutions, such as in University of Wisconsin (UW) solution, for preventing graft interstitial edema and cell swelling during cold preservation of donor organs. However, HES has undesirable characteristics, such as high viscosity, causing kidney injury and aggregation of erythrocytes. Hyperbranched polyglycerol (HPG) is a branched compact polymer that has low intrinsic viscosity. This study investigated HPG (MW-0.5 to 119 kDa) as a potential alternative to HES for cold organ preservation. HPG was synthesized by ring-opening multibranching polymerization of glycidol. Both rat myocardiocytes and human endothelial cells were used as an in vitro model, and heart transplantation in mice as an in vivo model. Tissue damage or cell death was determined by both biochemical and histological analysis. HPG polymers were more compact with relatively low polydispersity index than HES in UW solution. Cold preservation of mouse hearts ex vivo in HPG solutions reduced organ damage in comparison to those in HES-based UW solution. Both size and concentration of HPGs contributed to the protection of the donor organs; 1 kDa HPG at 3 wt% solution was superior to HES-based UW solution and other HPGs. Heart transplants preserved with HPG solution (1 kDa, 3%) as compared with those with UW solution had a better functional recovery, less tissue injury and neutrophil infiltration in syngeneic recipients, and survived longer in allogeneic recipients. In cultured myocardiocytes or endothelial cells, significantly more cells survived after cold preservation with the HPG solution than those with the UW solution, which was positively correlated with the maintenance of intracellular adenosine triphosphate and cell membrane fluidity. In conclusion, HPG solution significantly enhanced the protection of hearts or cells during cold storage, suggesting that HPG is a promising colloid for the cold storage of donor organs and cells in transplantation.     

Effects of benfotiamine and coenzyme Q10 on kidney damage induced gentamicin

Objective

Gentamicin (GM) is an effective antibiotic against severe infection but has limitations related to nephrotoxicity. In this study, we investigated whether benfotiamine (BFT) and coenzyme Q10 (CoQ10), could ameliorate the nephrotoxic effect of GM in rats.

Could the use of bedside lung ultrasound reduce the number of chest x-rays in the intensive care unit?

Background

Lung ultrasound can be used as an alternative to chest radiography (CXR) for the diagnosis and follow-up of various lung diseases in the intensive care unit (ICU). Our aim was to evaluate the influence that introducing a routine daily use of lung ultrasound in critically ill patients may have on the number of CXRs and as a consequence, on medical costs and radiation exposure.

Methods

Data were collected by conducting a retrospective evaluation of the medical records of adult patients who needed thoracic imaging and were admitted to our academic polyvalent ICU. We compared the number of CXRs and relative costs before and after the introduction of lung ultrasound in our ICU.

Results

A total of 4134 medical records were collected from January 2010 to December 2014. We divided our population into two groups, before (Group A, 1869 patients) and after (Group B, 2265 patients) the introduction of a routine use of LUS in July 2012. Group A performed a higher number of CXRs compared to Group B (1810 vs 961, P = 0.012), at an average of 0.97 vs 0.42 exams per patient. The estimated reduction of costs between Groups A and B obtained after the introduction of LUS, was 57%. No statistically significant difference between the outcome parameters of the two groups was observed.

Conclusions

Lung ultrasound was effective in reducing the number of CXRs and relative medical costs and radiation exposure in ICU, without affecting patient outcome.