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Purpose The aim of this study was to investigate two clinically approved plasma volume expanders (dextran 70 and voluven) as macromolecular MRI-chemical exchange saturation transfer (CEST) contrast agents to assess tumor vascular properties. Methods CEST contrast efficiency of both molecules (6% w/v) was measured in vitro at various irradiation saturation powers (1-6 μT for 5 s) and pH values (range, 5.5-7.9) and the exchange rate of hydroxyl protons was calculated. In vivo studies in a murine adenocarcinoma model (n = 4 mice for each contrast agent) upon i.v. injection provided CEST-derived perfusion tumor properties that were compared with those obtained with a gadolinium-based blood-pool agent (Gd-AAZTA-Madec). Results In vitro measurements showed a marked CEST contrast dependency to pH, with higher CEST contrast at lower pH values for both molecules. The measured prototropic exchange rates confirmed a base-catalyzed exchange rate that was faster for dextran 70 in comparison to voluven. Both molecules showed a similar CEST contrast increase (ΔST% > 3%) in the tumor tissue up to 30 min postinjection, with heterogeneous accumulation. In tumors receiving both CEST and T1 -weighted agents, a voxel-by-voxel analysis indicated moderate spatial correlation of perfusion properties between voluven/dextran 70 and Gd-AAZTA-Madec, suggesting different distribution patterns according to their molecular size. Conclusions The obtained results showed that both voluven and dextran 70 can be exploited as MRI-CEST contrast agents for evaluating tumor enhancement properties. Their increased accumulation in tumors and prolonged contrast enhancement promote their use as blood-pool MRI-CEST agents to examine tumor vascularization.

Cell interior is extremely congested with tightly packed biological macromolecules that exerts macromolecular crowding effect, influencing biophysical properties of proteins. To have a deeper insight into it we studied consequences of crowding on aggregation susceptibility and structural stability of α-chymotrypsinogen-A, pro-enzyme of serine protease family, upon addition of co-solvent reported to exert stress on polypeptides crafting favourable conditions for aggregation. Hexafluoropropan-2-ol (HFIP), a fluorinated alcohol caused structural disruption at 5% v/v unveiled by reduced intrinsic intensity and blue shifted ANS spectra. Significantly enhanced, red-shifted ThT and Congo red spectra sustained conformational changes concomitant with aggregation. FTIR and CD results confirmed transition of native structure to non-native extended, cross-linked beta-sheets. Transmission electron micrographs visibly exhibited incidence of amorphous aggregates. Macromolecular crowding, typically mimicked by concentrated solutions of dextran 70, was noticeably witnessed to defend conformational stability under denaturing condition. The native structure was retained maximally in presence of 100 mg/ml followed by 200 and 300 mg/ml dextran indicating concentration dependent deceleration of aggregate formation. It can be established that explicit consideration of crowding effects using relevant range of inert crowding agents must be a requisite for presumptions on intracellular conformational behaviour of proteins deduced from in vitro experiments.

Cell interiors are extremely congested with biological macromolecules exerting crowding effect, influencing various physiognomies of protein life. Present work deals with effect of crowding on folding behaviour of haemoglobin (Hb) under glycating conditions. Macromolecular crowding was mimicked by concentrated solutions of dextran 70. Hb with 0.2 M fructose and ribose was incubated separately for 96 h in dilute and crowded solution to analyse conformational changes. Reduced intrinsic and ANS fluorescence, decreased Soret absorbance, enhanced turbidity, browning of protein, red shift in ThT and Congo red spectra significantly unveiled protein aggregation. FTIR and CD results revealed transition from α-helix to β-sheets confirming aggregation. Transmission electron microscopy exhibited incidence of aggregates. Macromolecular crowding was witnessed to defend conformational stability of native Hb under stress condition at 100 mg/ml dextran, noticeably indicating deceleration of aggregation. Stabilising effect of crowding was marginally better in fructosylated Hb than with ribose due to difference in their glycation potential. Contrarily, in over-crowded solution where dextran concentration was 500 mg/ml, heightened aggregation was perceived implying concentration dependant, dual nature of macromolecular crowding. The novelty of this study lies in idea of considering macromolecular crowding as a key player in regulation of protein stability which was safely ignored previously.

Dextran 70 and its building block (glucose) has been used as macromolecular crowder and osmolyte, respectively. The difference in size and structure of both made us inquisitive to measure stability of lysozyme in the presence of their mixture. The effects of mixture of a fixed dextran 70 concentration (300 mg/ml) containing different concentrations of glucose and vice versa, were studied. It was observed that Tm (the midpoint of denaturation curve) and △GDo (standard Gibbs free energy change at 25 °C) of lysozyme increase with the increasing concentration of dextran 70 and glucose alone and their mixture. We asked a question whether the effect of synthetic crowding agent on the stability of protein is due to the property of its monomer or due to the crowder. In this study, we observed that both dextran and its monomer stabilize the protein by same mechanism which is volume exclusion. The stabilization arises due to change in in the entropy of unfolding, while there is insignificant change in enthalpy of the protein with increasing concentration of the co-solute. Furthermore, the efficacy of stabilization by glucose increases in the crowded environment, when the concentration of dextran 70 is more than 200 mg/ml in the mixture.

Protein-based pharmaceuticals are among the fastest growing categories of therapeutic agents in the clinic and as commercial products, and typically target high-impact areas such as various cancers, autoimmune diseases and metabolic disorders. The aim of our work was to explore the possibility of reducing the level of aggregation and improve the stability of the recombinant proteins AIMP1/p43 (aminoacyl-tRNA synthetase complex component of the higher eukaryotes) and antitumor cytokine EMAP II (proteolytic cleavage product of AIMP1/p43) in combination with dextran-70 polysaccharide for structural–functional research and development of new sustainable biomedical products. We studied interaction strength between these recombinant proteins with polymer by fluorescence spectroscopy and molecular docking. During experimental studies, optimal concentration ratio of AIMP1/p43 and EMAP II recombinant proteins with dextran-70 in which proteins bind to ligand and form complex was established. As a result of molecular docking investigations, spatial structure of the AIMP1/p43–dextran-70 and EMAP II–dextran-70 complexes was obtained and their binding energy was evaluation. The effect of temperature increase on the stability of these two complexes was determined by fluorescence spectroscopy method. It was found that dextran-70 specifically connects with recombinant proteins. Binding stoichiometry of dextran-70 with protein is about 1:1, which confirms the formation of a specific complex.

Aim. Determination of the effect of temperature on the aggregation properties of the recombinant cytokine EMAP II (endothelial monocyte activating polypeptide II) and its complex with polysaccharide dextran 70 in solution. Methods. Bacterial expression of recombinant protein, metal-chelated affinity chromatography, dynamic light scattering, spatial structure modeling. Results. The aggregation properties of the recombinant cytokine EMAP II and its complex with the dextran 70 were studied and the complex dimensions were determined by dynamic light scattering. The stabilization of the cytokine EMAP II with the dextran 70 was shown with increasing temperature in the range from 20 to 55° С. Using computer modelling of molecular docking, possible mechanisms for the aggregation of EMAP II cytokine and its stabilization with the dextran 70 were proposed. Conclusions. The results obtained indicate that the antitumor recombinant cytokine EMAP II forms protein aggregates with increasing temperature. The stability of the EMAP II structure in the complex expands the possibilities of studying the antitumor properties of this cytokine and its practical use.

The folding and unfolding of proteins inside a cell take place in the presence of macromolecules of various shapes and sizes. Such crowded conditions can significantly affect folding, stability, and biophysical properties of proteins. Thus, to logically mimic the intracellular environment, the thermodynamic stability of two different proteins (lysozyme and α-lactalbumin) was investigated in the presence of mixtures of three crowding agents (ficoll 70, dextran 70, and dextran 40) at different pH values. These crowders possess different shapes and sizes. It was observed that the stabilizing effect of mixtures of crowders is more than the sum effects of the individual crowder, i.e., the stabilizing effect is non-additive in nature. Moreover, dextran 40 (in the mixture) has been found to exhibit the greatest stabilization when compared with other crowders in the mixture. In other words, the small size of the crowder has been observed to be a dominant factor in stabilization of the proteins. Graphical Abstract.

Generally, in vivo function and structural changes are studied by probing proteins in a dilute solution under in vitro conditions, which is believed to be mimicking proteins in intracellular milieu. Earlier, thermal-induced denaturation of myoglobin, in the milieu of crowder molecule showed destabilization of the metal protein. Destabilization of protein by thermal-induced denaturation involves a large extrapolation, so, the reliability is questionable. This led us to measure the effects of macromolecular crowding on its stability by chemical-induced denaturation of the protein using probes like circular dichroism and absorption spectroscopy in the presence of dextran 70 and ficoll 70 at various pHs (acidic: 6.0, almost neutral: 7.0 and basic: 8.0). Observations showed that the degree of destabilization of myoglobin was greater due to ficoll 70 as compared to that of dextran 70 so it can be understood that the nature of the crowder or the shape of the crowder has an important role towards the stability of proteins. Additionally, the degree of destabilization was observed as pH dependent, however the pH dependence is different for different crowders. Furthermore, isothermal titration calorimetry and molecular docking studies confirmed that both the crowders (ficoll and dextran) bind to heme moiety of myoglobin and a single binding site was observed for each.

The role of crowding agents on structure and activities of heme proteins has been established. Analysis of kinetic and thermodynamic parameters measured for CO-dissociation reaction of natively-folded carbonmonoxycytochrome c (NCO) and carbonmonoxymyoglobin (MbCO) at different [GdnHCl] or [Urea] in the presence of crowding agents (dextran 40, dextran 70 and ficoll 70) demonstrate that (i) at low denaturant concentrations, crowder presence enhances the denaturant-mediated restricted dynamics of NCO and MbCO, and (ii) at higher denaturant concentrations, large scale unfolding-fluctuations dominate the dynamics and inclusion of crowder counteracts the structural-fluctuations causing the unfolding of proteins. Thermodynamic analysis of thermal and urea-unfolding curves of cytochrome c (Cyt c) and myoglobin (Mb) measured at different [GdnHCl] in presence of crowding agents reveals that crowder presence counterbalances and strengthens the destabilizing action of GdnHCl on stability of Cyt c and Mb, respectively. This study further demonstrates that the size, shape and concentration of crowding agent modulate the effect of crowder on denaturant-mediated dynamics and thermodynamic stability of heme proteins.

In the living cell, biomolecules perform their respective functions in the presence of not only one type of macromolecules but rather in the presence of various macromolecules with different shapes and sizes. In this study, we have investigated the effects of five single macromolecular crowding agents, Dextran 6, Dextran 40, Dextran 70, Ficoll 70, and PEG 8000 and their binary mixtures on the modulation in the domain separation of human serum albumin using a Förster resonance energy transfer-based approach and the translational mobility of a small fluorescent probe fluorescein isothiocyanate (FITC) using fluorescence correlation spectroscopy (FCS). Our observations suggest that mixed crowding induces greater cooperativity in the domain movement as compared to the components of the mixtures. Thermodynamic analyses of the same provide evidence of crossovers from enthalpy-based interactions to effects dominated by hard-sphere potential. When compared with those obtained for individual crowders, both domain movements and FITC diffusion studies show significant deviations from ideality, with an ideal solution being considered to be that arising from the sum of the contributions of those obtained in the presence of individual crowding agents. Considering the fact that domain movements are local (on the order of a few angstroms) in nature while translational movements span much larger lengthscales, our results imply that the observed deviation from simple additivity exists at several possible levels or lengthscales in such mixtures. Moreover, the nature and the type of deviation not only depend on the identities of the components of the crowder mixtures but are also influenced by the particular face of the serum protein (either the domain I–II or the domain II–III face) that the crowders interact with, thus providing further insights into the possible existence of microheterogeneities in such solutions.

The cytokine ЕМАР ІІ is endothelial and monocytic-activating polypeptide II, the precursor of which is the component of the high-molecular complex aminoacyl-tRNA synthetase of the higher eukaryotes of the protein p43, is capable of modulating the properties of endothelial cells, monocytes and leukocytes. In low concentrations the cytokine stimulates and in high concentrations it suppresses the migration of endothelial cells, stimulates their apoptosis, affects the activity of monocytes, neutrophils, macrophages, thus contributing to inflammatory and necrotic processes in malignant tumors. One of the promising directions of targeted therapy of oncological diseases is the use of antiangiogenic, prokoagulative and proapoptic drugs, which became the basis for the selection of an antitumor cytokine ЕМАР ІІ as an object of research. In the Institute of Molecular Biology and Genetics of the National Academy of Sciences of Ukraine, the biotechnology of bacterial expression of recombinant ЕМАР ІІ in E.coli BL21 (DE3) cells and isolation of highly purified cytokine preparations in preparative amounts have been developed. In order to increase the stability and reduce the aggregation of recombinant ЕМАР ІІ, scientific and methodological foundations were created and nanocomposite complexes of the cytokine EMAR II with biocompatible polymers with cyclodextrin and dextran 70 were obtained. In this experimental work, the effects of the nanocomposite complex EMAR II and dextran-70 on the animal organism were investigated for the purpose of establishing safety of its use. BALB / C mice were used as an object of research. Experimental studies have shown that acute and chronic administration of the drug to animals at doses of 300 – 10 000 μg / kg does not show the general toxic effects of the nanocomposite complex on the organism of mice. The obtained data open the prospect of further investigation of antitumor properties of the nanocomposite complex EMAR II with dextran-70 with the aim of possible further introduction into pharmacological practice.

Purpose: This study aimed to compare the efficacy of two sustained-release formulation of artificial tear drops. Patients and methods: This is a randomized patient-masked clinical trial, a total 88 patients into two group A (n = 41; with single dose of artificial tear, containing dextran 70, 1 mg/ml and hypromellose, 3 mg/ml hydroxypropyl methylcellulose (HPMC) and group B (n = 47; with multidose of artificial tear, containing 0.3 g HPMC and 0.1 g of dextran 70, with 0.01% benzalkonium chloride (BAK) as preservative) were completed the study. The ocular surface disease index (OSDI) questionnaire, tear break up time (TBUT), corneal and conjunctival staining and Schirmer test, were performed. Repeated measures ANOVA was used to assess the differences among the two products. A p-value less than 0.05 was considered significant. Results: The mean of age of the participants in the Group A and B was 44.08 ± 6.29 (range, 33–58 years) years and 45.83 ± 8.42 (31–60 years), respectively. In comparing two groups before the intervention, the OSDI scores, the TBUT scores, the conjunctival and corneal staining scores and the Schirmer scores did not show statistically significant differences (p = 0.339, p = 0.640, p = 0.334, p = 0.807 and p = 0.676, respectively). After 4 weeks, the OSDI scores, conjunctival and corneal staining scores showed improvement in compare to those before the intervention (p

The macromolecular crowding influences the structural stability and functional properties of transferrin (Tf). The equilibrium as well as kinetic studies of Tf at different concentrations of crowding agents (dextran 40, dextran 70, and ficoll 70) and at a fixed concentration of dextran 40 under different concentrations of NaCl at pH 7.4 and 5.6 (±1) revealed that (i) the crowder environment increases the diferric-Tf (Fe2Tf) stability against iron loss and overall denaturation of the protein, (ii) both in the absence and presence of crowder, the presence of salt promotes the loss of iron and overall denaturation of Fe2Tf which is due to ionic screening of electrostatic interactions, (iii) the crowder environment retards iron release from monoferric N-lobe of Tf (FeNTf) by increasing enthalpic barrier, (iv) the retardation of iron release by crowding is enthalpically dominated than the entropic one, (v) both in the absence and presence of crowder, the presence of salt accelerates the iron release from FeNTf due to ionic screening of electrostatic interactions and anion binding to KISAB sites, and (vi) the crowders environment is unable to diminish (a) the salt-induced destabilization of Fe2Tf against the loss of iron and overall denaturation and (b) the anion effect and ionic screening of diffusive counterions responsible to promote iron release from FeNTf.

To compare the efficacy of hypotensive resuscitation with hypertonic saline dextran 70 (HSD) and lactated Ringer (LR) solutions in a rat model of hemorrhagic shock at a simulated altitude of 4,000 m.Anesthetized rats were bled to maintain their mean arterial pressure (MAP) at 45 mm Hg for 1 h. The distal quarter of the tail was then amputated to allow free blood loss; rats were simultaneously resuscitated with 4 mL kg HSD (HSD group, n = 10) or 4 mL kg LR (LR group, n = 10), followed by hypotensive resuscitation with LR to maintain MAP at 55 to 60 mm Hg for 1 h. A control group received no resuscitation (n = 10). Afterward, the cut end of the tail was ligated. The MAP, acid-base balance, blood loss, volume of fluid infused, and survival were recorded.Compared with controls, HSD resuscitation improved MAP (without increasing uncontrolled blood loss), increased arterial pH and oxygen saturation (SaO2), decreased arterial lactate concentration at the end of resuscitation, and resulted in higher survival rate (P 0.05). Hypotensive resuscitation with LR also maintained higher MAP, pH, and SaO2 than the control group, but was associated with increased blood loss and inferior survival (P 0.05).For hemorrhagic shock at simulated high altitude, resuscitation of rats with a bolus of HSD was associated with reduced blood loss and serum lactate concentration, and superior SaO2, hemoglobin concentration and survival rate, compared with LR solution.

Red blood cell (RBC) aggregation highly influences hemorheology and blood microcirculation in the human body. The aggregation properties of RBCs can vary due to numerous factors, including RBC age. The aim of this work was to estimate in vitro the differences in the RBC aggregation properties of different RBC age populations in single-cell experiments using laser tweezers. RBCs from five healthy volunteers were separated into four subpopulations by Percoll density gradient centrifugation. Each subpopulation of the RBC was separately resuspended in autologous plasma or dextran 70 kDa (50 mg/mL). The aggregation force between the single cells was measured with holographic laser tweezers. The obtained data demonstrated an enhancement of RBC aggregation force in doublets with age: the older the cells, the higher the aggregation force. The obtained data revealed the differences between the aggregation and aggregability of RBC in dependence of the RBC in vivo age.

Мета. Визначення впливу температури на агрегаційні властивості рекомбінантного цитокіна ЕМАР ІІ (ендотеліальний моноцит, що активує поліпептид ІІ) та його комплексу з поліцукридом декстраном 70 в розчині. Методи. Бактеріальна експресія рекомбінантного білка, метал-хелатувальна афінна хроматографія, динамічне розсіювання світла, моделювання просторової структури. Результати. Досліджені агрегаційні властивості рекомбінантного цитокіна ЕМАР ІІ та його комплексу з декстраном 70 і встановлені розміри комплекса методом динамічного розсіювання світла. Показана стабілізація цитокіна ЕМАР ІІ декстраном 70 при підвищенні температури в межах від 20 °С до 55 °С. За допомогою комп’ютерного моделювання молекулярного докінгу запропоновані можливі механізми агрегації цитокіну ЕМАР ІІ та його стабілізації декстраном 70. Висновки. Отримані результати свідчать, що протипухлинний рекомбінантний цитокін ЕМАР ІІ утворює білкові агрегати при підвищенні температури. Стабільність цитокіна ЕМАР ІІ в розчині підвищується в результаті взаємодії з декстраном 70. Стабілізація структури ЕМАР ІІ в комплексі розширює можливості досліджень протипухлинних властивостей цього цитокіна та його практичного використання., Цель. Определение влияния температуры на агрегационные свойства рекомбинантного цитокина ЕМАР II (эндотелиальный моноцит активирующий полипептид II) и его комплекса с полисахаридом декстраном 70 в растворе. Методы. Бактериальная экспрессия рекомбинантного белка, металл-хелатирующая афинная хроматография, динамическое рассеяние света, моделирование пространственной структуры. Результаты. Исследованы агрегационные свойства рекомбинантного цитокина ЕМАР II и его комплекса с декстраном 70 и установлены размеры комплекса методом динамичного рассеивания света. Показана стабилизация цитокина ЕМАР II декстраном 70 при повышении температуры в пределах от 20 °С до 55 °С. С помощью компьютерного моделирования молекулярного докинга предложены возможные механизмы агрегации цитокина ЕМАР II и его стабилизации декстраном 70. Выводы. Полученные результаты свидетельствуют, что противоопухолевый рекомбинантный цитокин ЕМАР II образует белковые агрегаты при повышении температуры. Стабильность структуры ЕМАР II в комплексе расширяет возможности исследований противоопухолевых свойств этого цитокина и его практического использования., Aim. Determination of the effect of temperature on the aggregation properties of the recombinant cytokine EMAP II (endothelial monocyte activating polypeptide II) and its complex with polysaccharide dextran 70 in solution. Methods. Bacterial expression of recombinant protein, metal-chelated affinity chromatography, dynamic light scattering, spatial structure modeling. Results. The aggregation properties of the recombinant cytokine EMAP II and its complex with the dextran 70 were studied and the complex dimensions were determined by dynamic light scattering. The stabilization of the cytokine EMAP II with the dextran 70 was shown with increasing temperature in the range from 20 to 55° С. Using computer modelling of molecular docking, possible mechanisms for the aggregation of EMAP II cytokine and its stabilization with the dextran 70 were proposed. Conclusions. The results obtained indicate that the antitumor recombinant cytokine EMAP II forms protein aggregates with increasing temperature. The stability of the EMAP II structure in the complex expands the possibilities of studying the antitumor properties of this cytokine and its practical use.

There are a large number of biomolecules that are accountable for the extremely crowded intracellular environment, which is totally different from the dilute solutions, i.e., the idealized conditions. Such crowded environment due to the presence of macromolecules of different sizes, shapes, and composition governs the level of crowding inside a cell. Thus, we investigated the effect of different sizes and shapes of crowders (ficoll 70, dextran 70, and dextran 40), which are polysaccharide in nature, on the thermodynamic stability, structure, and functional activity of two model proteins using UV-Vis spectroscopy and circular dichroism techniques. We observed that (a) the extent of stabilization of &alpha, lactalbumin and lysozyme increases with the increasing concentration of the crowding agents due to the excluded volume effect and the small-sized and rod-shaped crowder, i.e., dextran 40 resulted in greater stabilization of both proteins than dextran 70 and ficoll 70, (b) structure of both the proteins remains unperturbed, and (c) enzymatic activity of lysozyme decreases with the increasing concentration of the crowder.

The static light scattering of solutions of Dextran 70 was measured as a function of concentration up to 100 g/l in pH 7.4 phosphate-buffered saline at temperatures between 5 – 37(o) C. The sedimentation equilibrium of identical solutions was measured under the same conditions. The concentration dependence of scattering intensity and the apparent molar mass obtained from sedimentation equilibrium were found to be nearly independent of temperature over this range to within the uncertainty of measurement. Global analysis of the concentration dependence of both properties yielded a reliable estimate of the concentration-dependent thermodynamic activity coefficient, a quantitative measure of the free energy of self-interaction. The self-interaction between Dextran molecules is compared with that of a globular protein (BSA) and a highly crosslinked polymer of similar molar mass (Ficoll 70). The observed concentration dependence of the free energy of Dextran self-interaction may be quantitatively accounted for by a simple semi-empirical model in which the polymer molecule is represented by a compressible sphere.

To compare the clinical efficacy of sodium hyaluronate eye drops, polyethylene glycol eye drops, and compound dextran eye drops in the treatment of dry eye after phacoemulsification of cataract. A total of 99 patients with dry eye after cataract phacoemulsification combined with intraocular lens implantation were treated in our hospital. Patients were divided into group A (sodium hyaluronate eye drops), group B (polyethylene glycol eye drops), and group C (dextran-70 eye drops). The clinical effect, tear film breakup time, basic tear secretion, corneal staining score, dry eye symptom score, and the incidence of ocular irritation were assessed. On the 3rd, 15th, 30th, and 60th day after operation, the tear film breakup time, corneal staining score, Schirmer I test, and dry eye symptom score in group A and group B were better than those in group C (P .05). At 3 days to 60 days after operation, the incidence of dry eye in group A (12.12%) and group B (18.18%) was lower than that in group C (39.39%), and the incidence of dry eye in group A was significantly lower than that in group B (P

To date, the mechanisms behind red blood cell (RBC) adhesion remain unclear. However, polymer depletion at the red cell surface has been shown to play a significant role. Interestingly, most previous studies have focused on the adhesion-promoting effects of one type of large polymer or plasma protein. However, the situation in vivo is more complex in that one needs to consider a mixture of various bio-macromolecules. To explore this complexity, Interference Reflection Microscopy was used to investigate how mixtures of various polymers affect RBC adhesion. RBC adhesion to albumin-coated glass coverslips was studied in the presence of two pro-adhesion polymers [dextran70 kDa and 35 kDa poly(ethylene glycol) (PEG 35)] with and without three types of smaller polymers: dextran 10 kDa, PEG 10 kDa and Poloxamer 188. Our findings show that the presence of small polymers can inhibit the adhesion-promoting effects of dextran 70 and PEG 35, with a more pronounced reduction for heterogeneous mixtures. Interpretation of our results in terms of the depletion model appears appropriate, in that our findings are consistent with the assumption that this reduction occurs because of an increase of small molecules in the depletion region. This study thus suggests that depletion interaction can control cell-cell interactions in complex environments (e.g., in vivo), and indicates that considering the interplay of all plasma constituents is important in order to understand the pathophysiology of diseases associated with cell adhesion and vascular complications.

Structural and molecular properties extracted from circular dichroism (CD), tryptophan fluorescence and 1-anilino-8-napthalene sulfonate (ANS) binding experiments suggest that the high concentration of synthetic crowding agents (dextran 40, dextran 70 and ficoll 70) stabilizes and refolds the base-denatured ferricytochrome c (Ferricyt c) and lysozyme (Lyz) at pH 12.9 (±0.1) to molten globule (MG) states (CB-states). These results further revealed that the CB-states resemble the generic properties of MG-states. Thermodynamic analysis of thermal denaturation curves of base-denatured Ferricyt c and Lyz at pH 12.9 (±0.1) under variable concentrations of crowding agents (dextran 40, dextran 70 and ficoll 70) revealed that the crowder presence increases the thermal stability of base-denatured proteins and also prevents the cold denaturation of Ferricyt c. The results further showed that the nature, size and shape of crowder influence the crowding-mediated increase in secondary structure stabilization and thermal stability of base-denatured Ferricyt c and Lyz. Analysis of kinetic and thermodynamic parameters measured for CO association reaction of alkaline ferrocytochrome c (Ferrocyt c) at pH 12.9 (±0.1) under variable concentrations of crowding agents (dextran 40, dextran 70 and ficoll 70) revealed that the crowder presence reduces the level of structural fluctuation of M80-containing Ω-loop that control CO association to alkaline Ferrocyt c.

Biological macromolecules are known to evolve and function under crowded intracellular environments that comprises of a wealth of soluble and insoluble macromolecules like proteins, nucleic acids, ribosomes and carbohydrates etc. Crowded environment is known to result in altered biological properties including thermodynamic, structural and functional aspect of macromolecules as compared to the macromolecules present in our commonly used experimental dilute buffers. In this study, we have investigated the effect of Dextran 70 on the thermodynamic and structural properties of three different proteins (Ribonuclease-A, lysozyme and holo α-lactalbumin) at different pH values. We discovered that Dextran 70 has a protein-independent effect in terms of protein stability and structure.

Domain movements play a fundamental and critical role in the specific biological function that multidomain proteins have evolved to perform. A significant amount of research has been carried out to investigate the effects of macromolecular crowding agents, mostly on single domain proteins, thereby furthering our appreciation for the crowding phenomenon. However similar studies on proteins having multiple domains are relatively scarce. Using the plasma protein human serum albumin (HSA) as the protein of interest, we have probed the influence of dextran based crowding agents (Dextran 6, Dextran 40, and Dextran 70) on the relative movements of domains I and II using FRET, with Trp-214 in domain II acting as the donor and acrylodan (Ac) covalently attached to Cys-34 of domain I as the acceptor. Amongst the higher molecular weight crowders, while both Dextran 70 and Dextran 40 induced a significant decrease in the distance between the aforesaid domains, however for the latter macromolecular crowder (Dextran 40), beyond 50 g L(-1), no change in domain separation was observed even up to concentrations of 175 g L(-1). On the other hand, contrary to our expectations, Dextran 6, having the highest packing density by virtue of it being the smallest crowding agent used, provided an asymmetric excluded volume which resulted in forced elongation of HSA along the Trp-Ac FRET axis. Additionally both chemical and thermal studies performed at varying concentrations of the chemical denaturant, urea, reveal unusual movements of the two domains, an aspect that can have important implications with regard to HSA being an avid transporter of fatty acids, with the binding of latter being known to invoke appreciable domain displacements. We hypothesise that we see a distinct crossover from entropy dominated depletion effects in the case of Dextran 6 to significant enthalpic contribution for Dextran 70 with Dextran 40 lying midway between these two crowders, having characteristics of both.

BACKGROUND Renal ischemia-reperfusion (IR) leads to alterations of tubular epithelial cells, interstitial microvasculopathy and endothelial cell dysfunction in peritubular capillaries. Although dextrans have deteriorative effects on healthy kidney, their favorable effects on postischemic microvascular disturbances have been demonstrated. Therefore, we aimed to investigate in vivo effects of systemic dextran 70 administration in kidney tissue with ischemia-reperfusion injury. METHODS Twenty-one rats were allocated as sham, IR and IR+ dextran 70 treatment groups. Perirenal dissection without ischemia-reperfusion injury was performed with 0.9 NaCl solution infusions in the sham group. The left renal ischemia-reperfusion injury model was induced with % 0.9 NaCl and dextran 70 solutions infusion in the IR and IR+ dextran 70 treatment groups, respectively. At the end of the experimental procedures, histopathologic findings, serum creatinine and blood urea nitrogen levels, 24 hour urinary volumes, urinary albumin, KIM-1and IL-18 levels, and tissue MDA and SOD levels were compared between the groups. RESULTS We determined slightly reduction of the histopathologic structural changes and significant reduced levels of the albuminuria and KIM-1 in the IR +dextran 70 treatment group (P=0.03 and P=0.02, respectively). Higher 24 hour urine out put and free radical scavenger SOD levels were also detected with Dextran 70 treatment (P=0.0 and P=0.03, respectively). CONCLUSIONS Intravenous Dextran 70 infusion has some substantial protective effects against the ischemic injury of kidney.

BACKGROUND: Dextran-70 is a more potent plasma volume expander than albumin but use has been hampered because of it's antithrombotic properties. However, also albumin has antithrombotic properties and little is known about relative effects of these two colloids on coagulation in-vivo when controlling for differences in efficacy as plasma volume expanders.AIM: Compare effects of dextran-70 and albumin on coagulation at a dose resulting in equal plasma volume expansion.METHODS: Guinea pigs were subjected to a 25 ml/kg hemorrhage during 20 minutes and randomized to resuscitation with either 6% dextran-70 at a dose of 15 ml/kg or 5% albumin at a dose of 25 ml/kg (n = 14 in each group) during 30 minutes starting one hour of shock. Blood samples were collected at completion of resuscitation and at 4 hours. Plasma volume was measured using I-albumin and effect on coagulation was evaluated using whole blood thrombelastography (TEG), measurement of plasma fibrinogen and von Willebrand factor (vWF) concentrations and vWF GP1bA activity.RESULTS: Plasma volumes after resuscitation were similar in the groups at both time points. Dextran-70 resulted in a transient prolongation of TEG clot amplification time (K) at completion of resuscitation compared to albumin. TEG clot initiation (R) and strength (MA) did not differ between the treatments at any of the time points. Albumin reduced vWF concentrations to a larger extent than dextran at both time points whereas no difference in p-vWF GP1bA activity or in plasma fibrinogen and could be detected.CONCLUSION: In equipotent doses with regard to plasma volume expansion, dextran-70 transiently prolongs clot amplification time more than albumin whereas dextran-70 reduces plasma vWF concentrations less than albumin.This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0.

Background Albumin may be beneficial in patients with septic shock but availability is limited and cost is high. The objective of the present study was to investigate if the use of dextran-70 in addition to albumin and crystalloids influences organ failure or mortality in patients with severe sepsis or septic shock. Methods Patients with severe sepsis or septic shock (n = 778) admitted to a university hospital intensive care unit (ICU) between 2007 and 2015 that received dextran-70 during resuscitation were propensity score matched to controls at a 1 to 1 ratio. Outcomes were highest acute kidney injury network (AKIN) score the first 10 days in the ICU, use of renal replacement therapy, days alive and free of organ support the first 28 days after admission to ICU, mortality and events of severe bleeding. Outcomes were assessed using paired hypothesis testing. Results Propensity score matching resulted in two groups of patients with 245 patients in each group. The dextran group received a median volume of 1483 ml (interquartile range, 1000–2000 ml) of dextran-70 during the ICU stay. Highest AKIN score did not differ between the control- and dextran groups (1 (0–3) versus 2 (0–3), p = 0.06). Incidence of renal replacement therapy in the control- and dextran groups was similar (19% versus 22%, p = 0.42, absolute risk reduction −2.9% [95% CI: −9.9 to 4.2]). Days alive and free of renal replacement, vasopressors and mechanical ventilation did not differ between the control- and dextran groups. The 180-day mortality was 50.2% in the control group and 41.6% in the dextran group (p = 0.046, absolute risk reduction 8.6% [−0.2 to 17.4]). Fraction of patients experiencing a severe bleeding in the first 10 days in the ICU did not differ between the control and dextran groups (14% versus 18%, p = 0.21). Discussion There is a paucity of high quality data regarding effects of dextran solutions on outcome in sepsis. In the present study, propensity score matching was used in attempt to reduce bias. Conclusion No evidence to support a detrimental effect of dextran-70 on mortality or on organ failures in patients with severe sepsis or septic shock could be detected. Electronic supplementary material The online version of this article (doi:10.1186/s13049-017-0413-x) contains supplementary material, which is available to authorized users.

Background: The present study was undertaken to identify factors that correlate with the gain in body weight after surgery. Methods: Twenty-one patients (median age of 49 years) were randomized to receive either Ringer × s acetate or 6% dextran 70 as their first infusion fluid during cholecystectomy or hysterectomy. Each patient's body weight was measured before the surgery and on the first postoperative morning. Blood and urine samples were analyzed for signs of stress, inflammation, and kidney injury. The fluid retention index (FRI), which reflects how strongly the kidneys excrete or retain fluid, was also calculated. Results: The body weight increased by a median of 0.4 kg in the crystalloid fluid group and by 1.0 kg in the colloid fluid group (maximum 2.5 kg, P < 0.01). This difference was due to less urinary excretion after surgery in the colloid group (P < 0.03). The increase in body weight did not correlate with the infused fluid volume, the plasma concentrations of C-reactive protein or cortisol, or the urinary excretion of albumin, cortisol, or neutrophil gelatinase-associated lipocalin. However, the body weight increased with the postoperative FRI score (r = 0.64; P < 0.003) and with the surgery-induced change in FRI score (r = 0.72; P < 0.002). Conclusion: How strongly the kidneys excrete or retain fluid, which can be assessed by urine sampling, was the strongest indicator of the increase in body weight during the day of surgery. The amount of fluid alone did not correlate with the gain in body weight.

In this prospective randomized clinical trial, 2 different barrier solutions (icodextrin 4% vs. dextran 70) were compared with regard to their antiadhesive properties, their tolerance and their persistence in situ. To this end, 45 patients suffering from infertility due to adnexal adhesions with indication for microsurgical adhesiolysis were randomized to 2 treatment groups. In advance of abdominal closure, patients were randomized to receive either 1,000 mL of icodextrin 4% solution (n = 23) or 300 mL dextran 70 instillation (n = 22). Serial transvaginal ultrasonographic scans were conducted on days 1, 3, 5 and 7 after surgery to measure the remaining volumes of each barrier solution. Seven days after initial surgery, a second-look laparoscopy was performed; remaining fluids were aspirated and measured and adhesions were rescored (final adhesion score). Differences between treatment groups were not significant (p = 0.775). With regard to their tolerance, the advantages of the icodextrin 4% solution became obvious, as edema of vulva and abdomen occurred more frequently after dextran 70 instillation. In conclusion, microsurgical adhesiolysis and application of icodextrin 4% solution or dextran 70 as adhesion-prevention agent resulted in reduction of incidence, extent and severity of adhesions. Both solutions were well tolerated.

Erythrocytes kept outside the blood circulation undergo progressive changes in metabolism, shape and function, which was the topic of this study. For that purpose, blood anticoagulated with either heparin, citrate or EDTA was incubated at temperatures of 5 ◦ C, 22 ◦ Co r 37 ◦ C for 0 h, 24 h and 48 h, respectively. A temperature- and time-dependent decrease of glucose and ATP and increase of lactate and LDH were observed. An erythrocyte swelling and echinocytic shape transformation, which was also time- and temperature-dependent, was seen. Density-separated young and old erythrocytes behaved similarly. The degree of echinocytic shape transformation correlated with the increase in blood viscosity at high shear rate. Echinocytosis was partially reversible when erythrocytes were suspended in buffer containing 0.2% albumin. This phenomenon is specific for albumin, since molecules with a similar molecular weight (dextran 70, heat shock protein, protein C) had no effect. These finding may have an impact on blood banking and transfusion medicine.

Consumption of red wine is associated with a decreased risk of several cardiovascular diseases (e.g., coronary artery disease, stroke), but unfortunately literature reports regarding ethanol’s effects on hemorheological parameters are not concordant. In the present study, red blood cell (RBC) deformability was tested via laser ektacytometry (LORCA, 0.3 – 30 Pa) using two approaches: 1) addition of ethanol to whole blood at 0.25% – 2% followed by incubation and testing in ethanol-free LORCA medium; 2) addition of ethanol to the LORCA medium at 0.25% – 6% then testing untreated native RBC in these media. The effects of ethanol on deformability for oxidatively stressed RBC were investigated as were changes of RBC aggregation (Myrenne Aggregometer) for cells in autologous plasma or 3% 70 kDa dextran. Significant dose-related increases of RBC deformability were observed at 0.25% (p

In this study, we quantitatively examined the effects of the macromolecular crowding agents, polyethylene glycol 2000 (PEG 2000) and dextran 70, on guanidine hydrochloride (GdnHCl)-induced denaturation of recombinant human brain-type creatine kinase (rHBCK). Our results showed that both PEG 2000 and dextran 70 had a protective effect on the inactivation of rHBCK induced by 0.5 M GdnHCl at 25 °C. The presence of 200 g/L PEG 2000 resulted in the retention of 35.33 % of rHBCK activity after 4 h of inactivation, while no rHBCK activity was observed after denaturation in the absence of macromolecular crowding agents. The presence of PEG 2000 and dextran 70 at a concentration of 100 g/L could decelerate the k 2 value of the slow track to 21 and 33 %, respectively, in comparison to values obtained in the absence of crowding agents. Interestingly, inactivation of rHBCK in the presence of 200 g/L PEG 2000 followed first-order monophasic kinetics, with an apparent rate constant of 8 × 10−5 s−1. The intrinsic fluorescence results showed that PEG 2000 was better than dextran 70 at stabilizing rHBCK conformation. In addition, the results of the phase diagram indicate that more intermediates may be captured when rHBCK is denatured in a macromolecular crowding system. Mixed crowding agents did not produce better results than single crowding agents, but the protective effects of PEG 2000 on the inactivation and unfolding of rHBCK tended to increase as the ratio of PEG 2000 increased in the mixed crowding agent solution. Though it is not clear which crowding agents more accurately simulated the intracellular environment, this study could lead to a better understanding of protein unfolding in the intracellular environment.

Crowding and confinement have often been used synonymously with regard to their effect on the structure and dynamics of proteins. In this work, we have investigated the unfolding of the protein myoglobin (Mb) entrapped in the confinement of the water pool of AOT reverse micelles and in the presence of some commonly used macromolecular crowding agents (Ficoll 70, Dextran 70, and Dextran 40). Our results reveal that confinement effects can be quite destabilizing in nature for Mb with the extent of distortion depending on a host of factors apart from the size of the confining cage. Effects of the crowding agents on myoglobin also show a deviation from the general notion that synthetic macromolecular crowding agents are always stabilizing in nature. Ficoll 70 was observed to be particularly destabilizing in its influence on Mb unfolding. Moreover, tryptophan lifetime studies point to the fact that the Trp-heme distance in Mb might not always be a reliable probe of the secondary structural dissolution of the protein.

The folding of protein, an important process for protein to fulfill normal functions, takes place in crowded physiological environments. α-Lactalbumin, as a model system for protein-folding studies, has been used extensively because it can form stable molten globule states under a range of conditions. Here we report that the crowding agents Ficoll 70, dextran 70, and polyethylene glycol (PEG) 2000 have different effects on the structural stability of human α-lactalbumin (HLA) represented by the transition to a molten globule state: dextran 70 dramatically enhances the thermal stability of Ca(2+)-depleted HLA (apo-HLA) and Ficoll 70 enhances the thermal stability of apo-HLA to some extent, while PEG 2000 significantly decreases the thermal stability of apo-HLA. Ficoll 70 and dextran 70 have no obvious effects on trypsin degradation of apo-HLA but PEG 2000 accelerates apo-HLA degradation by trypsin and destabilizes the native conformation of apo-HLA. Furthermore, no interaction is observed between apo-HLA and Ficoll 70 or dextran 70, but a weak, non-specific interaction between the apo form of the protein and PEG 2000 is detected, and such a weak, non-specific interaction could overcome the excluded-volume effect of PEG 2000. Our data are consistent with the results of protein stability studies in cells and suggest that stabilizing excluded-volume effects of crowding agents can be ameliorated by non-specific interactions between proteins and crowders.

Whole blood viscosity has been considered as a significant clinical parameter in diagnosis and prevention of various cardiovascular diseases and a useful reference to monitor certain diseases. The blood viscosity can be influenced by several factors, such as red blood cell aggregation, hematocrit, and plasma viscosity. In many cardiovascular disease conditions, the concentration of plasma proteins (particularly fibrinogen) increases and this effect may elevate the aggregation level of red blood cells as well as plasma viscosity. This kind of phenomenon can also be observed in many in vitro studies that utilize high molecular weight dextrans (Dextran 70 and Dextran 500) to induce red blood cell aggregation. The red blood cells in such a dextran medium in general show a tendency of aggregation. Furthermore, with increasing dextran concentration, not only the aggregation level but also medium viscosity rises. In such case, it becomes difficult to determine individual quantitative effects of aggregation and plasma viscosity on blood viscosity, in particular on red blood cell viscosity. Information on the red blood cell viscosity is important in the microcirculation since a phase-separation phenomenon becomes apparent in microvessels, which leads to formation of a plasma layer near the vessel wall and a red blood cell rich region near the centerline. Thus, the viscosity in the core region (red blood cell viscosity) becomes much higher than the effective viscosity of blood. The Refutas model was first introduced to estimate the viscosity of oil mixture. This model can be used to predict the viscosity of a fluid mixture by measuring viscosities of individual fluid components. Alternatively, this model can be used to estimate the viscosity of an unknown component from the viscosity of its mixture. In this study, we attempted to use the Refutas model in estimating the viscosity of packed red blood cells by measuring blood and medium viscosities. Thus, the main purpose of the present study was to examine possibility of applying Refutas model to quantify the sole effect of red blood cell aggregation on red blood cell viscosity.

Background: Colloid fluids influence the coagulation system by diluting the plasma and, potentially, by exerting other effects that are unique for each fluid product. We hypothesised that changes in the coagulation measured at the end of surgery would be mainly governed by differences in half-life between the colloid fluids. Methods: Eighty-four patients were randomised to receive one of four colloids: HES 130/0.42/6 : 1 (Venofundin (R)), 130/0.4/9 : 1 (Voluven (R)), 200/0.5/5 : 1 (Haes-steril (R)) and 6% dextran 70 (Macrodex (R)). Blood samples were taken just before and after a preoperative 500ml bolus, and also after subsequent elective hip replacement surgery. Volume expansion was estimated from the blood dilution and coagulation assessed by ROTEM, activated partial thromboplastin time, prothrombin international normalised ratio (PT-INR), D-dimer and thrombin-antithrombin complex (TAT). Results: The blood volume expansion amounted to approximately 600 ml for all four colloids directly after infusion. Voluven (R) and Haes-steril (R) prolonged the aPT time and Venofundin (R) increased TAT. Although all colloids increased PT-INR and D-dimer, the ROTEM analyses showed that they consistently shortened the clotting time and weakened the clot strength. These effects were mainly unchanged after surgery, during which the haemorrhage averaged 500-600 ml. Macrodex (R) produced a stronger volume support at the end of the surgery (91% of infused volume; Pless than0.001) than the three starch solutions (42-60%). Conclusions: All tested colloid fluids induced a mild hypercoagulable state with faster clotting, but with weaker clot strength. The additive influence of surgery was relatively small, and postoperative changes in coagulation were mainly due to differences in the half-life of each colloid.

Mechanical and electrical properties of the normal RBCs suspensions and of hardened after treatment with glutaraldehyde (0.01-2.5%) RBCs in isotonic physiological solution and Dextran 70,000 (Dextran 70) and Polyethylene glycol 35,000 (PEG) and adjusted to hematocrit of 40%, were evaluated. Apparent viscosity and conductivity were measured under steady and transient flow regimes at low shear rates and at different local structure of the flow at 37 °C. A time course of conductivity was recorded in parallel with the rheological properties of the RBC suspensions and conductivity and apparent viscosity dependences on shear rates were studied and compared at different concentrations of Dextran 70, PEG and glutaraldehyde. Low shear viscosity decreased after RBCs treatment with glutaraldehyde and at 0.5-2.5% it is constant. Echinocytes are observed at low Dextran 70 and PEG concentrations while spherocytes are found mainly in smears treated with higher concentrations. The results show that the apparent viscosity and conductivity of RBCs suspensions in Dextran 70 and PEG are strongly influenced by flow, shear rates, concentration, cell deformability and morphology and the method is sensitive to study the mechanical and electrical properties of RBC suspension and to provide experimental description of RBCs and other cell-to-cell interactions.

The paper presents results of a study of dynamics of dextran transportation through a synthetic membrane separating the system made of the infusion liquid and water. Changes in the optical density on both sides of the membrane permit the application of the sensitive method of optical interference for analysis of changes in the solution concentration, determination of the dextran molecule radius and the parameters characterising the membrane permeability. The membrane pore size was estimated under a scanning electron microscope.

This study aimed to investigate whether a small volume of 7.2% hypertonic saline solution with 6% dextran 70 (HSD) is superior to mannitol in vasodilatation of encephalic vessels in the dogs using magnetic resonance imaging (MRI). Fifteen healthy 2.4 ± 0.9 year-old purpose-bred male Beagle dogs were assigned to receive 5 mL/kg of isotonic saline solution (ISS) as control, 20% mannitol or HSD infusion at a flow rate of 20 mL/kg/hours via right cephalic vein.Venous blood samples were collected immediately before fluid infusion (pre) and every 15 minutes until 120 minutes after the initiation of fluid infusion. Immediately after collection of each blood sample, T1 and T2-weighted magnetic resonance imaging recordings were undergone. Immediately after HSD infusion, the area of the cross-section of superior sagittal sinus was significantly greater than that of beagles in the other groups (p < 0.001), reaching the 2.09 ± 0.25 times prevalue. During the 120 minutes period of observation after the initiation of fluid infusion, HSD infusion significantly reduced the area of the cross-section of CSF compared with the mannitol group ((p < 0.001). Our results indicate that HSD induced a rapid and strong reduction in the area of the cross-section of CSF more than mannitol did. Therefore, it is suggested that 5 mL/kg of HSD might be superior to isovolume of mannitol in inducing vasodilatation in the dog.

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.