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1.
Transplant Direct ; 10(4): e1609, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38481967

ABSTRACT

Background: Brief normothermic machine perfusion is increasingly used to assess and recondition grafts before transplant. During normothermic machine perfusion, metabolic activity is typically maintained using red blood cell (RBC)-based solutions. However, the utilization of RBCs creates important logistical constraints. This study explored the feasibility of human kidney normothermic perfusion using William's E-based perfusate with no additional oxygen carrier. Methods: Sixteen human kidneys declined for transplant were perfused with a perfusion solution containing packed RBCs or William's E medium only for 6 h using a pressure-controlled system. The temperature was set at 37 °C. Renal artery resistance, oxygen extraction, metabolic activity, energy metabolism, and histological features were evaluated. Results: Baseline donor demographics were similar in both groups. Throughout perfusion, kidneys perfused with William's E exhibited improved renal flow (P = 0.041) but similar arterial resistance. Lactic acid levels remained higher in kidneys perfused with RBCs during the first 3 h of perfusion but were similar thereafter (P = 0.95 at 6 h). Throughout perfusion, kidneys from both groups exhibited comparable behavior regarding oxygen consumption (P = 0.41) and reconstitution of ATP tissue concentration (P = 0.55). Similarly, nicotinamide adenine dinucleotide levels were preserved during perfusion. There was no evidence of histological damage caused by either perfusate. Conclusions: In human kidneys, William's E medium provides a logistically convenient, off-the-shelf alternative to packed RBCs for up to 6 h of normothermic machine perfusion.

2.
Nat Commun ; 13(1): 4008, 2022 07 15.
Article in English | MEDLINE | ID: mdl-35840553

ABSTRACT

The limited preservation duration of organs has contributed to the shortage of organs for transplantation. Recently, a tripling of the storage duration was achieved with supercooling, which relies on temperatures between -4 and -6 °C. However, to achieve deeper metabolic stasis, lower temperatures are required. Inspired by freeze-tolerant animals, we entered high-subzero temperatures (-10 to -15 °C) using ice nucleators to control ice and cryoprotective agents (CPAs) to maintain an unfrozen liquid fraction. We present this approach, termed partial freezing, by testing gradual (un)loading and different CPAs, holding temperatures, and storage durations. Results indicate that propylene glycol outperforms glycerol and injury is largely influenced by storage temperatures. Subsequently, we demonstrate that machine perfusion enhancements improve the recovery of livers after freezing. Ultimately, livers that were partially frozen for 5-fold longer showed favorable outcomes as compared to viable controls, although frozen livers had lower cumulative bile and higher liver enzymes.


Subject(s)
Cryoprotective Agents , Ice , Animals , Cryopreservation/methods , Cryoprotective Agents/pharmacology , Freezing , Liver , Perfusion/methods , Rats
3.
Comb Chem High Throughput Screen ; 24(3): 328-341, 2021.
Article in English | MEDLINE | ID: mdl-32342810

ABSTRACT

BACKGROUND: Considering the low ocular bioavailability of conventional formulations used for ocular bacterial infection treatment, there is a need to design efficient novel drug delivery systems that may enhance precorneal retention time and corneal permeability. AIM AND OBJECTIVE: The current research focuses on developing nanosized and non-toxic Eudragit® RL 100 and Kollidon® SR nanoparticles loaded with moxifloxacin hydrochloride (MOX) for its prolonged release to be promising for effective ocular delivery. METHODS: In this study, MOX incorporation was carried out by spray drying method aiming ocular delivery. In vitro characteristics were evaluated in detail with different methods. RESULTS: MOX was successfully incorporated into Eudragit® RL 100 and Kollidon® SR polymeric nanoparticles by a spray-drying process. Particle size, zeta potential, entrapment efficiency, particle morphology, thermal, FTIR, NMR analyses and MOX quantification using HPLC method were carried out to evaluate the nanoparticles prepared. MOX loaded nanoparticles demonstrated nanosized and spherical shape while in vitro release studies demonstrated modified-release pattern, which followed the Korsmeyer-Peppas kinetic model. Following the successful incorporation of MOX into the nanoparticles, the formulation (MOX: Eudragit® RL 100, 1:5) (ERL-MOX 2) was selected for further studies because of its better characteristics like cationic zeta potential, smaller particle size, narrow size distribution and more uniform prolonged release pattern. Moreover, ERLMOX 2 formulation remained stable for 3 months and demonstrated higher cell viability values for MOX. CONCLUSION: In vitro characterization analyses showed that non-toxic, nano-sized and cationic ERL-MOX 2 formulation has the potential of enhancing ocular bioavailability.


Subject(s)
Moxifloxacin/pharmacology , Nanoparticles/chemistry , Polymethacrylic Acids/chemistry , Povidone/chemistry , 3T3 Cells , Animals , Cell Survival/drug effects , Dose-Response Relationship, Drug , Drug Carriers/chemistry , Drug Compounding , Drug Liberation , Kinetics , Mice , Moxifloxacin/chemistry , Particle Size
4.
Nat Protoc ; 15(6): 2024-2040, 2020 06.
Article in English | MEDLINE | ID: mdl-32433625

ABSTRACT

Preservation of human organs at subzero temperatures has been an elusive goal for decades. The major complication hindering successful subzero preservation is the formation of ice at temperatures below freezing. Supercooling, or subzero non-freezing, preservation completely avoids ice formation at subzero temperatures. We previously showed that rat livers can be viably preserved three times longer by supercooling as compared to hypothermic preservation at +4 °C. Scalability of supercooling preservation to human organs was intrinsically limited because of volume-dependent stochastic ice formation at subzero temperatures. However, we recently adapted the rat preservation approach so it could be applied to larger organs. Here, we describe a supercooling protocol that averts freezing of human livers by minimizing air-liquid interfaces as favorable sites of ice nucleation and uses preconditioning with cryoprotective agents to depress the freezing point of the liver tissue. Human livers are homogeneously preconditioned during multiple machine perfusion stages at different temperatures. Including preparation, the protocol takes 31 h to complete. Using this protocol, human livers can be stored free of ice at -4 °C, which substantially extends the ex vivo life of the organ. To our knowledge, this is the first detailed protocol describing how to perform subzero preservation of human organs.


Subject(s)
Liver/physiology , Organ Preservation/methods , Cold Temperature , Cryoprotective Agents/chemistry , Equipment Design , Freezing , Humans , Ice/analysis , Liver/chemistry , Organ Preservation/instrumentation , Perfusion/instrumentation , Perfusion/methods
5.
J Clin Med ; 9(1)2020 Jan 18.
Article in English | MEDLINE | ID: mdl-31963739

ABSTRACT

Ex situ machine perfusion is a promising technology to help improve organ viability prior to transplantation. However, preclinical studies using discarded human livers to evaluate therapeutic interventions and optimize perfusion conditions are limited by significant graft heterogeneity. In order to improve the efficacy and reproducibility of future studies, a split-liver perfusion model was developed to allow simultaneous perfusion of left and right lobes, allowing one lobe to serve as a control for the other. Eleven discarded livers were surgically split, and both lobes perfused simultaneously on separate perfusion devices for 3 h at subnormothermic temperatures. Lobar perfusion parameters were also compared with whole livers undergoing perfusion. Similar to whole-liver perfusions, each lobe in the split-liver model exhibited a progressive decrease in arterial resistance and lactate levels throughout perfusion, which were not significantly different between right and left lobes. Split liver lobes also demonstrated comparable energy charge ratios. Ex situ split-liver perfusion is a novel experimental model that allows each graft to act as its own control. This model is particularly well suited for preclinical studies by avoiding the need for large numbers of enrolled livers necessary due to the heterogenous nature of discarded human liver research.

6.
J Vis Exp ; (152)2019 10 25.
Article in English | MEDLINE | ID: mdl-31710044

ABSTRACT

Vitrification is a promising ice-free alternative for classic slow-freezing (at approximately 1 °C/min) cryopreservation of biological samples. Vitrification requires extremely fast cooling rates to achieve transition of water into the glass phase while avoiding injurious ice formation. Although pre-incubation with cryoprotective agents (CPA) can reduce the critical cooling rate of biological samples, high concentrations are generally needed to enable ice-free cryopreservation by vitrification. As a result, vitrification is hampered by CPA toxicity and restricted to small samples that can be cooled fast. It was recently demonstrated that these inherent limitations can be overcome by bulk droplet vitrification. Using this novel method, cells are first pre-incubated with a low intracellular CPA concentration. Leveraging rapid osmotic dehydration, the intracellular CPA is concentrated directly ahead of vitrification, without the need to fully equilibrate toxic CPA concentrations. The cellular dehydration is performed in a fluidic device and integrated with continuous high throughput generation of large sized droplets that are vitrified in liquid nitrogen. This ice-free cryopreservation method with minimal CPA toxicity is suitable for large cell quantities and results in increased hepatocyte viability and metabolic function as compared to classical slow-freezing cryopreservation. This manuscript describes the methods for successful bulk droplet vitrification in detail.


Subject(s)
Cryopreservation/methods , Cryoprotective Agents/chemistry , Hepatocytes/cytology , Vitrification , Freezing , Phase Transition , Water
7.
Nat Biotechnol ; 37(10): 1131-1136, 2019 10.
Article in English | MEDLINE | ID: mdl-31501557

ABSTRACT

The inability to preserve vascular organs beyond several hours contributes to the scarcity of organs for transplantation1,2. Standard hypothermic preservation at +4 °C (refs. 1,3) limits liver preservation to less than 12 h. Our group previously showed that supercooled ice-free storage at -6 °C can extend viable preservation of rat livers4,5 However, scaling supercooling preservation to human organs is intrinsically limited because of volume-dependent stochastic ice formation. Here, we describe an improved supercooling protocol that averts freezing of human livers by minimizing favorable sites of ice nucleation and homogeneous preconditioning with protective agents during machine perfusion. We show that human livers can be stored at -4 °C with supercooling followed by subnormothermic machine perfusion, effectively extending the ex vivo life of the organ by 27 h. We show that viability of livers before and after supercooling is unchanged, and that after supercooling livers can withstand the stress of simulated transplantation by ex vivo normothermic reperfusion with blood.


Subject(s)
Cold Temperature , Liver/physiology , Organ Preservation/methods , Humans , Organ Preservation Solutions , Perfusion , Tissue Survival
8.
Technology (Singap World Sci) ; 7(1-2): 1-11, 2019.
Article in English | MEDLINE | ID: mdl-31414037

ABSTRACT

Due to the growth of cell-based therapeutic alternatives addressing the shortage of livers for transplant, there is necessity for a reliable source of human hepatocytes. In addition, pharmaceutical research often requires human hepatocytes to assess new drug therapies during development or to achieve FDA approval. Whole human livers producing large quantities of cells from the same donor are ideal, enhancing reproducibility for all purposes, while also allowing for capturing variances in drug-metabolism across different demographics for pharmaceutical testing and development but are limited in availability and quality for research purposes. The present study investigates the effect of donor and liver procurement factors of 16 human livers on cell viability and yield, showing that typical exclusion criteria for transplant still produce viable hepatocytes with significant yields. Although limited in number of data points, which should be taken into consideration, the conclusions of this study could be utilized as indications, allowing for expansion of liver selection criteria for hepatocyte isolation and provide the necessary quality hepatocytes in large quantities for the growing pharmaceutical, biomedical, and therapeutic research fields.

9.
Am J Transplant ; 19(10): 2814-2824, 2019 10.
Article in English | MEDLINE | ID: mdl-30938927

ABSTRACT

Normothermic machine perfusion presents a novel platform for pretransplant assessment and reconditioning of kidney grafts. Maintaining the metabolic activity of a preserved graft at physiologic levels requires an adequate oxygen supply, typically delivered by crystalloid solutions supplemented with red blood cells. In this study, we explored the feasibility of using a synthetic hemoglobin-based oxygen carrier (HBOC) in human kidney normothermic perfusion. Fourteen discarded human kidneys were perfused for 6 hours at a mean temperature of 37°C using a pressure-controlled system. Kidneys were perfused with a perfusion solution supplemented with either HBOC (n = 7) or packed red blood cells (PRBC) (n = 7) to increase oxygen-carrying capacity. Renal artery resistance, oxygen extraction, metabolic activity, energy stores, and histological features were evaluated. Throughout perfusion, kidneys from both groups exhibited comparable behavior regarding vascular flow (P = .66), oxygen consumption (P = .88), and reconstitution of tissue adenosine triphosphate (P = .057). Lactic acid levels were significantly higher in kidneys perfused with PRBC (P = .007). Histological findings were comparable between groups, and there was no evidence of histological damage caused by the HBOC. This feasibility experiment demonstrates that a HBOC solution can offer a logistically more convenient off-the-shelf alternative to PRBC in normothermic machine perfusion of human kidneys.


Subject(s)
Blood Substitutes/pharmacology , Hemoglobins/pharmacology , Kidney/drug effects , Organ Preservation Solutions/chemistry , Organ Preservation/methods , Oxygen/metabolism , Reperfusion Injury/prevention & control , Adult , Aged , Cells, Cultured , Erythrocytes/chemistry , Extracorporeal Circulation , Female , Follow-Up Studies , Humans , Male , Middle Aged , Oxygen Consumption , Perfusion , Tissue Survival , Tissue and Organ Harvesting/methods
10.
Langmuir ; 35(23): 7354-7363, 2019 06 11.
Article in English | MEDLINE | ID: mdl-30514081

ABSTRACT

Loss of hepatocyte viability and metabolic function after cryopreservation is still a major issue. Although vitrification is a promising alternative, it has generally been proven to be unsuitable for vitrification of large cell volumes which is required for clinical applications. Here, we propose a novel bulk droplet (3-5 mm diameter) vitrification method which allows high throughput volumes (4 mL/min), while using a low preincubated CPA concentration (15% v/v) to minimize toxicity and loss of cell viability and function. We used rapid (1.25 s) osmotic dehydration to concentrate a low preincubated intracellular CPA concentration ahead of vitrification, without the need of fully equilibrating toxic CPA concentrations. We compared direct postpreservation viability, long-term viability, and metabolic function of bulk droplet vitrified, cryopreserved, and fresh hepatocytes. Simulations and cooling rate measurements confirmed an adequate concentration of the intracellular CPA concentration (up to 8.53 M) after dehydration in combination with high cooling rates (960-1320 °C/min) for successful vitrification. In comparison to cryopreserved hepatocytes, bulk droplet vitrified hepatocytes had a significantly higher viability, directly after preservation and after 1 day in culture. Moreover, bulk droplet vitrified hepatocytes had evidently better morphology and showed significantly higher metabolic activity than cryopreserved hepatocytes in long-term collagen sandwich cultures. In conclusion, we developed a novel bulk droplet vitrification method of which we validated the theoretical background and demonstrated the feasibility to use this method to vitrify large cell volumes. Moreover, we showed that this method results in improved hepatocyte viability and metabolic function as compared to cryopreservation.


Subject(s)
Cryopreservation/instrumentation , Hepatocytes/cytology , Animals , Cell Membrane/metabolism , Cell Survival , Feasibility Studies , Female , Hydrodynamics , Rats
11.
Blood ; 130(1): 73-83, 2017 07 06.
Article in English | MEDLINE | ID: mdl-28438754

ABSTRACT

Anemia suppresses liver hepcidin expression to supply adequate iron for erythropoiesis. Erythroferrone mediates hepcidin suppression by anemia, but its mechanism of action remains uncertain. The bone morphogenetic protein (BMP)-SMAD signaling pathway has a central role in hepcidin transcriptional regulation. Here, we explored the contribution of individual receptor-activated SMADs in hepcidin regulation and their involvement in erythroferrone suppression of hepcidin. In Hep3B cells, SMAD5 or SMAD1 but not SMAD8, knockdown inhibited hepcidin (HAMP) messenger RNA (mRNA) expression. Hepatocyte-specific double-knockout Smad1fl/fl;Smad5fl/fl;Cre+ mice exhibited ∼90% transferrin saturation and massive liver iron overload, whereas Smad1fl/fl;Smad5fl/wt;Cre+ mice or Smad1fl/wt;Smad5fl/fl;Cre+ female mice with 1 functional Smad5 or Smad1 allele had modestly increased serum and liver iron, and single-knockout Smad5fl/fl;Cre+ or Smad1fl/fl;Cre+ mice had minimal to no iron loading, suggesting a gene dosage effect. Hamp mRNA was reduced in all Cre+ mouse livers at 12 days and in all Cre+ primary hepatocytes. However, only double-knockout mice continued to exhibit low liver Hamp at 8 weeks and failed to induce Hamp in response to Bmp6 in primary hepatocyte cultures. Epoetin alfa (EPO) robustly induced bone marrow erythroferrone (Fam132b) mRNA in control and Smad1fl/fl;Smad5fl/fl;Cre+ mice but suppressed hepcidin only in control mice. Likewise, erythroferrone failed to decrease Hamp mRNA in Smad1fl/fl;Smad5fl/fl;Cre+ primary hepatocytes and SMAD1/SMAD5 knockdown Hep3B cells. EPO and erythroferrone reduced liver Smad1/5 phosphorylation in parallel with Hamp mRNA in control mice and Hep3B cells. Thus, Smad1 and Smad5 have overlapping functions to govern hepcidin transcription. Moreover, erythropoietin and erythroferrone target Smad1/5 signaling and require Smad1/5 to suppress hepcidin expression.


Subject(s)
Erythropoietin/metabolism , Hepatocytes/metabolism , Hepcidins/metabolism , Smad1 Protein/metabolism , Smad5 Protein/metabolism , Animals , Cell Line , Cytokines/genetics , Cytokines/metabolism , Erythropoietin/genetics , Hepcidins/genetics , Mice , Mice, Knockout , Muscle Proteins/genetics , Muscle Proteins/metabolism , Smad1 Protein/genetics , Smad5 Protein/genetics
12.
Artif Organs ; 41(6): 579-585, 2017 Jun.
Article in English | MEDLINE | ID: mdl-27862079

ABSTRACT

Treatment for end-stage liver failure is restricted by the critical shortage of donor organs; about 4000 people die in the USA while waiting for a transplantable organ. This situation has been a major driving force behind the rise of tissue engineering to build artificial tissues/organs. Recent advancements in creating transplantable liver grafts using decellularized liver scaffolds bring the field closer to clinical translation. However, a source of readily available and highly functional adult hepatocytes in adequate numbers for regenerative liver therapies still remains unclear. Here, we describe a new method to utilize discarded livers to make transplantable new liver grafts. We show that marginal donor livers damaged due to warm ischemia could be treated with machine perfusion to yield 39 million viable hepatocytes per gram of liver, similar to fresh livers, and these cells could be used to repopulate decellularized liver matrix (DLM) scaffolds to make transplantable liver grafts. The hepatocytes from recovered livers sustained their characteristic epithelial morphology while they exhibited slightly lower protein synthesis functions both in plate cultures and in recellularized liver grafts. The dampened protein synthesis was attributed to residual endoplasmic reticulum stress found in recovered cells. The results here represent a unique approach to reengineer transplantable liver grafts solely from discarded organs.


Subject(s)
Hepatocytes/cytology , Liver Regeneration , Liver/physiology , Tissue Engineering/methods , Animals , Cell Separation , Cells, Cultured , Extracellular Matrix/chemistry , Liver/chemistry , Liver/cytology , Perfusion , Rats , Tissue Scaffolds/chemistry
13.
Tissue Eng Part C Methods ; 22(7): 671-8, 2016 07.
Article in English | MEDLINE | ID: mdl-27169332

ABSTRACT

Whole liver engineering holds the promise to create transplantable liver grafts that may serve as substitutes for donor organs, addressing the donor shortage in liver transplantation. While decellularization and recellularization of livers in animal models have been successfully achieved, scale up to human livers has been slow. There are a number of donor human livers that are discarded because they are not found suitable for transplantation, but are available for engineering liver grafts. These livers are rejected due to a variety of reasons, which in turn may affect the decellularization outcome. Hence, a one-size-fit-for all decellularization protocol may not result in scaffolds with consistent matrix quality, subsequently influencing downstream recellularization and transplantation outcomes. There is a need for a noninvasive monitoring method to evaluate the extent of cell removal, while ensuring preservation of matrix components during decellularization. In this study, we decellularized rat livers using a protocol previously established by our group, and we monitored decellularization through traditional destructive techniques, including evaluation of DNA, collagen, and glycosaminoglycan (GAG) content in decellularized scaffolds, as well as histology. In addition, we used computed tomography and perfusate analysis as alternative nondestructive decellularization monitoring methods. We found that DNA removal correlates well with the Hounsfield unit of the liver, and perfusate analysis revealed that significant amount of GAG is removed during perfusion with 0.1% sodium dodecyl sulfate. This allowed for optimization of our decellularization protocol leading to scaffolds that have significantly higher GAG content, while maintaining appropriate removal of cellular contents. The significance of this is the creation of a nondestructive monitoring strategy that can be used for optimization of decellularization protocols for individual human livers available for liver engineering.


Subject(s)
Cell Separation/methods , Liver/cytology , Tissue Engineering/methods , Tissue Scaffolds , Animals , Female , Liver/physiology , Models, Animal , Perfusion , Rats , Rats, Inbred Lew
14.
Sci Rep ; 6: 22415, 2016 Mar 03.
Article in English | MEDLINE | ID: mdl-26935866

ABSTRACT

As donor organ shortages persist, functional machine perfusion is under investigation to improve preservation of the donor liver. The transplantation of donation after circulatory death (DCD) livers is limited by poor outcomes, but its application may be expanded by ex vivo repair and assessment of the organ before transplantation. Here we employed subnormothermic (21 °C) machine perfusion of discarded human livers combined with metabolomics to gain insight into metabolic recovery during machine perfusion. Improvements in energetic cofactors and redox shifts were observed, as well as reversal of ischemia-induced alterations in selected pathways, including lactate metabolism and increased TCA cycle intermediates. We next evaluated whether DCD livers with steatotic and severe ischemic injury could be discriminated from 'transplantable' DCD livers. Metabolomic profiling was able to cluster livers with similar metabolic patterns based on the degree of injury. Moreover, perfusion parameters combined with differences in metabolic factors suggest variable mechanisms that result in poor energy recovery in injured livers. We conclude that machine perfusion combined with metabolomics has significant potential as a clinical instrument for the assessment of preserved livers.


Subject(s)
Liver/metabolism , Metabolome , Organ Preservation , Perfusion , Female , Humans , Liver Transplantation , Male , Organ Preservation/instrumentation , Organ Preservation/methods , Perfusion/instrumentation , Perfusion/methods
15.
Biomaterials ; 75: 37-46, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26476196

ABSTRACT

A key challenge to the clinical implementation of decellularized scaffold-based tissue engineering lies in understanding the process of removing cells and immunogenic material from a donor tissue/organ while maintaining the biochemical and biophysical properties of the scaffold that will promote growth of newly seeded cells. Current criteria for evaluating whole organ decellularization are primarily based on nucleic acids, as they are easy to quantify and have been directly correlated to adverse host responses. However, numerous proteins cause immunogenic responses and thus should be measured directly to further understand and quantify the efficacy of decellularization. In addition, there has been increasing appreciation for the role of the various protein components of the extracellular matrix (ECM) in directing cell growth and regulating organ function. We performed in-depth proteomic analysis on four types of biological scaffolds and identified a large number of both remnant cellular and ECM proteins. Measurements of individual protein abundances during the decellularization process revealed significant removal of numerous cellular proteins, but preservation of most structural matrix proteins. The observation that decellularized scaffolds still contain many cellular proteins, although at decreased abundance, indicates that elimination of DNA does not assure adequate removal of all cellular material. Thus, proteomic analysis provides crucial characterization of the decellularization process to create biological scaffolds for future tissue/organ replacement therapies.


Subject(s)
Proteomics/methods , Tissue Scaffolds/chemistry , Animals , Blotting, Western , Collagen/pharmacology , Collagen Type I/metabolism , DNA/metabolism , Drug Combinations , Female , Humans , Intercellular Signaling Peptides and Proteins/metabolism , Laminin/pharmacology , Liver/drug effects , Liver/metabolism , Lung/metabolism , Proteoglycans/pharmacology , Rats, Inbred Lew
16.
Cryobiology ; 71(1): 125-9, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25936340

ABSTRACT

Cold storage (at 4°C) offers a compromise between the benefits and disadvantages of cooling. It allows storage of organs or cells for later use that would otherwise quickly succumb to warm ischemia, but comprises cold ischemia that, when not controlled properly, can result in severe damage as well by both similar and unique mechanisms. We hypothesized that polyethylene glycol (PEG) 35 kDa would ameliorate these injury pathways and improve cold primary hepatocyte preservation. We show that reduction of the storage temperature to below zero by means of supercooling, or subzero non-freezing, together with PEG supplementation increases the viable storage time of primary rat hepatocytes in University of Wisconsin (UW) solution from 1 day to 4 days. We find that the addition of 5% PEG 35 kDa to the storage medium prevents cold-induced lipid peroxidation and maintains hepatocyte viability and functionality during storage. These results suggest that PEG supplementation in combination with supercooling may enable a more optimized cell and organ preservation.


Subject(s)
Cold Ischemia/methods , Cryopreservation/methods , Hepatocytes/physiology , Organ Preservation/methods , Polyethylene Glycols/pharmacology , Animals , Cell Survival/drug effects , Cells, Cultured , Cold Temperature , Cryoprotective Agents/pharmacology , Hepatocytes/drug effects , Lipid Peroxidation/drug effects , Organ Preservation Solutions/pharmacology , Primary Cell Culture , Rats
17.
PLoS One ; 10(3): e0123421, 2015.
Article in English | MEDLINE | ID: mdl-25822248

ABSTRACT

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.


Subject(s)
Biomarkers/metabolism , Liver/metabolism , Liver/pathology , Warm Ischemia/adverse effects , Adenosine Triphosphate/metabolism , Adult , Aged , Alanine Transaminase/metabolism , Aspartate Aminotransferases/metabolism , Cold Ischemia/methods , Cryopreservation/methods , Female , Hepatic Artery/metabolism , Hepatic Artery/pathology , Humans , L-Lactate Dehydrogenase/metabolism , Liver Transplantation/adverse effects , Liver Transplantation/methods , Male , Middle Aged , Organ Preservation/methods , Organ Preservation Solutions/metabolism , Portal Vein/metabolism , Portal Vein/pathology
18.
J Clin Transl Res ; 1(1): 48-56, 2015 Jul 20.
Article in English | MEDLINE | ID: mdl-30873444

ABSTRACT

BACKGROUND: Tissue-engineered liver grafts may offer a viable alternative to orthotopic liver transplantation and help overcome the donor organ shortage. Decellularized liver matrices (DLM) have a preserved vasculature and sustain hepatocellular function in culture, but graft survival after transplantation remains limited due to thrombogenicity of the matrix. AIM: To evaluate the effect of heparin immobilization on DLM thrombogenicity. METHODS: Heparin was immobilized on DLMs by means of layer-by-layer deposition. Grafts with 4 or 8 bilayers and 2 or 4 g/L of heparin were recellularized with primary rat hepatocytes and maintained in culture for 5 days. Hemocompatibility of the graft was assessed by ex vivo diluted whole-blood perfusion and heterotopic transplantation. RESULTS: Heparin was deposited throughout the matrix and the heparin content in the graft was higher with increasing number of bilayers and concentration of heparin. Recellularization and in vitro albumin and urea production were unaffected by heparinization. Resistance to blood flow during ex vivo perfusion was lower with increased heparinization and, macroscopically, no clots were visible in grafts with 8 bilayers. Following transplantation, flow through the graft was limited in all groups. Histological evidence of thrombosis was lower in heparinized DLMs, but transplantation of DLM grafts was not improved. CONCLUSIONS: Layer-by-layer deposition of heparin on a DLM is an effective method of immobilizing heparin throughout the graft and does not impede recellularization or hepatocellular function in vitro. Thrombogenicity during ex vivo blood perfusion was reduced in heparinized grafts and optimal with 8 bilayers, but transplantation remained unsuccessful with this method. RELEVANCE FOR PATIENTS: Tissue engineered liver grafts may offer a viable solution to dramatic shortages in donor organs.

19.
PLoS One ; 8(7): e69334, 2013.
Article in English | MEDLINE | ID: mdl-23874947

ABSTRACT

Supercooling preservation holds the potential to drastically extend the preservation time of organs, tissues and engineered tissue products, and fragile cell types that do not lend themselves well to cryopreservation or vitrification. Here, we investigate the effects of supercooling preservation (SCP at -4(o)C) on primary rat hepatocytes stored in cryovials and compare its success (high viability and good functional characteristics) to that of static cold storage (CS at +4(o)C) and cryopreservation. We consider two prominent preservation solutions a) Hypothermosol (HTS-FRS) and b) University of Wisconsin solution (UW) and a range of preservation temperatures (-4 to -10 (o)C). We find that there exists an optimum temperature (-4(o)C) for SCP of rat hepatocytes which yields the highest viability; at this temperature HTS-FRS significantly outperforms UW solution in terms of viability and functional characteristics (secretions and enzymatic activity in suspension and plate culture). With the HTS-FRS solution we show that the cells can be stored for up to a week with high viability (~56%); moreover we also show that the preservation can be performed in large batches (50 million cells) with equal or better viability and no loss of functionality as compared to smaller batches (1.5 million cells) performed in cryovials.


Subject(s)
Cryopreservation/methods , Hepatocytes/cytology , Animals , Cells, Cultured , Organ Preservation Solutions , Rats , Solutions , Temperature
20.
J Obstet Gynaecol Res ; 32(4): 422-7, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16882269

ABSTRACT

AIM: This prospective, single-blind and controlled clinical study aimed to research if CA-125 levels could be a useful test in the differential diagnosis of intact and ruptured tubal ectopic pregnancy. METHODS: Sixty-five women with tubal ectopic pregnancy of 5-10 weeks' duration (27 women with ruptured tubal ectopic pregnancy [REP] and 38 women with unruptured tubal ectopic pregnancy [UREP]) and 65 women with normal intrauterine pregnancy (NIUP) of the same gestational age were studied prospectively. Serum CA-125 levels were measured in all women and these levels were compared among the REP, UREP, and NIUP groups. RESULTS: The mean CA-125 levels didn't show any significant difference between the REP and NIUP groups (P > 0.05). The mean CA-125 levels of these two groups were higher than that in the UREP group (P < 0.01, P < 0.001, respectively). The dispersion ratios of the CA-125 levels had a statistically significant difference between the REP and UREP groups (chi(2): 42.44, P < 0.0001). CA-125 levels weren't correlated with gestational weeks in the REP and UREP groups (r: 0.005, P > 0.05; r: 0.008, P > 0.05, respectively). CONCLUSION: In intact tubal ectopic pregnancies, expectant or managed with medical treatment, the increase of CA-125 levels in the serial measurements could be a supplementary test for an early diagnosis of tubal rupture.


Subject(s)
CA-125 Antigen/blood , Pregnancy, Tubal/blood , Pregnancy, Tubal/diagnosis , Diagnosis, Differential , Female , Humans , Pregnancy , Prospective Studies , ROC Curve , Rupture, Spontaneous/blood , Rupture, Spontaneous/diagnosis , Statistics, Nonparametric
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