scholarly journals Development of a Novel Perfusable Solution for ex vivo Preservation: Towards Photosynthetic Oxygenation for Organ Transplantation

2021 ◽  
Vol 9 ◽  
Author(s):  
Valentina Veloso-Giménez ◽  
Rosalba Escamilla ◽  
David Necuñir ◽  
Rocío Corrales-Orovio ◽  
Sergio Riveros ◽  
...  
Keyword(s):  
Organ Transplantation ◽  
Organ Preservation ◽  
First Generation ◽  
Ex Vivo ◽  
Rat Kidney ◽  
Animal Cells ◽  
Renal Vasculature ◽  
Metabolic Requirement ◽  
Photosynthetic Microorganisms ◽  
Key Aspects

Oxygen is the key molecule for aerobic metabolism, but no animal cells can produce it, creating an extreme dependency on external supply. In contrast, microalgae are photosynthetic microorganisms, therefore, they are able to produce oxygen as plant cells do. As hypoxia is one of the main issues in organ transplantation, especially during preservation, the main goal of this work was to develop the first generation of perfusable photosynthetic solutions, exploring its feasibility for ex vivo organ preservation. Here, the microalgae Chlamydomonas reinhardtii was incorporated in a standard preservation solution, and key aspects such as alterations in cell size, oxygen production and survival were studied. Osmolarity and rheological features of the photosynthetic solution were comparable to human blood. In terms of functionality, the photosynthetic solution proved to be not harmful and to provide sufficient oxygen to support the metabolic requirement of zebrafish larvae and rat kidney slices. Thereafter, isolated porcine kidneys were perfused, and microalgae reached all renal vasculature, without inducing damage. After perfusion and flushing, no signs of tissue damage were detected, and recovered microalgae survived the process. Altogether, this work proposes the use of photosynthetic microorganisms as vascular oxygen factories to generate and deliver oxygen in isolated organs, representing a novel and promising strategy for organ preservation.

scholarly journals Evaluation of 2D super-resolution ultrasound imaging of the rat renal vasculature using ex vivo micro-computed tomography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sofie Bech Andersen ◽  
Iman Taghavi ◽  
Hans Martin Kjer ◽  
Stinne Byrholdt Søgaard ◽  
Carsten Gundlach ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Rat Kidney ◽  
Vascular Anatomy ◽  
Super Resolution ◽  
Sprague Dawley ◽  
Micro Computed Tomography ◽  
Renal Vasculature

AbstractSuper-resolution ultrasound imaging (SRUS) enables in vivo microvascular imaging of deeper-lying tissues and organs, such as the kidneys or liver. The technique allows new insights into microvascular anatomy and physiology and the development of disease-related microvascular abnormalities. However, the microvascular anatomy is intricate and challenging to depict with the currently available imaging techniques, and validation of the microvascular structures of deeper-lying organs obtained with SRUS remains difficult. Our study aimed to directly compare the vascular anatomy in two in vivo 2D SRUS images of a Sprague–Dawley rat kidney with ex vivo μCT of the same kidney. Co-registering the SRUS images to the μCT volume revealed visually very similar vascular features of vessels ranging from ~ 100 to 1300 μm in diameter and illustrated a high level of vessel branching complexity captured in the 2D SRUS images. Additionally, it was shown that it is difficult to use μCT data of a whole rat kidney specimen to validate the super-resolution capability of our ultrasound scans, i.e., validating the actual microvasculature of the rat kidney. Lastly, by comparing the two imaging modalities, fundamental challenges for 2D SRUS were demonstrated, including the complexity of projecting a 3D vessel network into 2D. These challenges should be considered when interpreting clinical or preclinical SRUS data in future studies.

scholarly journals Combination of mesenchymal stromal cells and machine perfusion is a novel strategy for organ preservation in solid organ transplantation

2021 ◽  
Author(s):  
Lingfei Zhao ◽  
Chenxia Hu ◽  
Fei Han ◽  
Dajin Chen ◽  
Yanhong Ma ◽  
...  
Keyword(s):  
Organ Transplantation ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Organ Preservation ◽  
Ex Vivo ◽  
Solid Organ Transplantation ◽  
Organ Shortage ◽  
Solid Organ ◽  
Machine Perfusion ◽  
Organ Function

AbstractOrgan preservation is a prerequisite for an urgent increase in the availability of organs for solid organ transplantation (SOT). An increasing amount of expanded criteria donor (ECD) organs are used clinically. Currently, the paradigm of organ preservation is shifting from simple reduction of cellular metabolic activity to maximal simulation of an ex vivo physiological microenvironment. An ideal organ preservation technique should not only preserve isolated organs but also offer the possibility of rehabilitation and evaluation of organ function prior to transplantation. Based on the fact that mesenchymal stromal cells (MSCs) possess strong regeneration properties, the combination of MSCs with machine perfusion (MP) is expected to be superior to conventional preservation methods. In recent years, several studies have attempted to use this strategy for SOT showing promising outcomes. With better organ function during ex vivo preservation and the potential of utilization of organs previously deemed untransplantable, this strategy is meaningful for patients with organ failure to help overcome organ shortage in the field of SOT.

scholarly journals Cellular localization of adenine receptors in the rat kidney and their functional significance in the inner medullary collecting duct

2013 ◽  
Vol 305 (9) ◽  
pp. F1298-F1305 ◽  
Author(s):  
Bellamkonda K. Kishore ◽  
Yue Zhang ◽  
Haykanush Gevorgyan ◽  
Donald E. Kohan ◽  
Anke C. Schiedel ◽  
...  
Keyword(s):  
Cellular Localization ◽  
Ex Vivo ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Apical Plasma Membrane ◽  
Renal Vasculature ◽  
Outer Medulla ◽  
Collecting Ducts ◽  
Rabbit Polyclonal Antibody ◽  
Immunofluorescence Labeling

The Gi-coupled adenine receptor (AdeR) binds adenine with high affinity and potentially reduces cellular cAMP levels. Since cAMP is an important second messenger in the renal transport of water and solutes, we localized AdeR in the rat kidney. Real-time RT-PCR showed higher relative expression of AdeR mRNA in the cortex and outer medulla compared with the inner medulla. Immunoblots using a peptide-derived and affinity-purified rabbit polyclonal antibody specific for an 18-amino acid COOH-terminal sequence of rat AdeR, which we generated, detected two bands between ∼30 and 40 kDa (molecular mass of native protein: 37 kDa) in the cortex, outer medulla, and inner medulla. These bands were ablated by preadsorption of the antibody with the immunizing peptide. Immunofluorescence labeling showed expression of AdeR protein in all regions of the kidney. Immunoperoxidase revealed strong labeling of AdeR protein in the cortical vasculature, including the glomerular arterioles, and less intense labeling in the cells of the collecting duct system. Confocal immunofluorescence imaging colocalized AdeR with aquaporin-2 protein to the apical plasma membrane in the collecting duct. Functionally, adenine (10 μM) significantly decreased ( P < 0.01) 1-deamino-8-d-arginine vasopressin (10 nM)-induced cAMP production in ex vivo preparations of inner medullary collecting ducts, which was reversed by PSB-08162 (20 μM, P < 0.01), a selective antagonist of AdeR. Thus, we demonstrated the expression of AdeR in the renal vasculature and collecting ducts and its functional relevance. This study may open a new avenue for the exploration of autocrine/paracrine regulation of renal vascular and tubular functions by the nucleobase adenine in health and disease.

scholarly journals Adhesion-dependent and Contractile Ring-independent Equatorial Furrowing during Cytokinesis in Mammalian Cells

2005 ◽  
Vol 16 (8) ◽  
pp. 3865-3872 ◽  
Author(s):  
Masamitsu Kanada ◽  
Akira Nagasaki ◽  
Taro Q.P. Uyeda
Keyword(s):  
Mammalian Cells ◽  
Rat Kidney ◽  
Myosin Ii ◽  
Rho Kinase ◽  
Cellular Slime Mold ◽  
Animal Cells ◽  
Contractile Ring ◽  
Normal Rat ◽  
Cellular Slime ◽  
Coated Surfaces

Myosin II-dependent contraction of the contractile ring drives equatorial furrowing during cytokinesis in animal cells. Nonetheless, myosin II-null cells of the cellular slime mold Dictyostelium divide efficiently when adhering to substrates by making use of polar traction forces. Here, we show that in the presence of 30 μM blebbistatin, a potent myosin II inhibitor, normal rat kidney (NRK) cells adhering to fibronectin-coated surfaces formed equatorial furrows and divided in a manner strikingly similar to myosin II-null Dictyostelium cells. Such blebbistatin-resistant cytokinesis was absent in partially detached NRK cells and was disrupted in adherent cells if the advance of their polar lamellipodia was disturbed by neighboring cells. Y-27632 (40 μM), which inhibits Rho-kinase, was similar to 30 μM blebbistatin in that it inhibited cytokinesis of partially detached NRK cells but only prolonged furrow ingression in attached cells. In the presence of 100 μM blebbistatin, most NRK cells that initiated anaphase formed tight furrows, although scission never occurred. Adherent HT1080 fibrosarcoma cells also formed equatorial furrows efficiently in the presence of 100 μM blebbistatin. These results provide direct evidence for adhesion-dependent, contractile ring-independent equatorial furrowing in mammalian cells and demonstrate the importance of substrate adhesion for cytokinesis.

scholarly journals Mechanism of the formation of contractile ring in dividing cultured animal cells. II. Cortical movement of microinjected actin filaments.

1990 ◽  
Vol 111 (5) ◽  
pp. 1905-1911 ◽  
Author(s):  
L G Cao ◽  
Y L Wang
Keyword(s):  
Actin Filaments ◽  
Average Rate ◽  
Rat Kidney ◽  
Equatorial Region ◽  
Cell Cortex ◽  
Polar Regions ◽  
Cortical Actin ◽  
Animal Cells ◽  
Contractile Ring ◽  
Directional Movement

The contractile ring in dividing animal cells is formed primarily through the reorganization of existing actin filaments (Cao, L.-G., and Y.-L. Wang. 1990. J. Cell Biol. 110:1089-1096), but it is not clear whether the process involves a random recruitment of diffusible actin filaments from the cytoplasm, or a directional movement of cortically associated filaments toward the equator. We have studied this question by observing the distribution of actin filaments that have been labeled with fluorescent phalloidin and microinjected into dividing normal rat kidney (NRK) cells. The labeled filaments are present primarily in the cytoplasm during prometaphase and early metaphase, but become associated extensively with the cell cortex 10-15 min before the onset of anaphase. This process is manifested both as an increase in cortical fluorescence intensity and as movements of discrete aggregates of actin filaments toward the cortex. The concentration of actin fluorescence in the equatorial region, accompanied by a decrease of fluorescence in polar regions, is detected 2-3 min after the onset of anaphase. By directly tracing the distribution of aggregates of labeled actin filaments, we are able to detect, during anaphase and telophase, movements of cortical actin filaments toward the equator at an average rate of 1.0 micron/min. Our results, combined with previous observations, suggest that the organization of actin filaments during cytokinesis probably involves an association of cytoplasmic filaments with the cortex, a movement of cortical filaments toward the cleavage furrow, and a dissociation of filaments from the equatorial cortex.

Sepsis induces changes in the expression and distribution of Toll-like receptor 4 in the rat kidney

2006 ◽  
Vol 290 (5) ◽  
pp. F1034-F1043 ◽  
Author(s):  
Tarek M. El-Achkar ◽  
Xiaoping Huang ◽  
Zoya Plotkin ◽  
Ruben M. Sandoval ◽  
Georges J. Rhodes ◽  
...  
Keyword(s):  
Rat Kidney ◽  
Expression Patterns ◽  
Cecal Ligation ◽  
Proximal Tubules ◽  
Microbial Pathogens ◽  
Sprague Dawley ◽  
Renal Vasculature ◽  
Two Photon Microscopy ◽  
Sprague Dawley Rats ◽  
Cellular Signal

Toll-like receptors (TLRs) are now recognized as the major receptors for microbial pathogens on cells of the innate immune system. Recently, TLRs were also identified in many organs including the kidney. However, the cellular distribution and role of these renal TLRs remain largely unknown. In this paper, we investigated the expression of TLR4 in a cecal ligation and puncture (CLP) model of sepsis in Sprague-Dawley rats utilizing fluorescence microscopy. In sham animals, TLR4 was expressed predominantly in Tamm-Horsfall protein (THP)-positive tubules. In CLP animals, TLR4 expression increased markedly in all tubules (proximal and distal), glomeruli, and the renal vasculature. The staining showed a strong apical distribution in all tubules. A moderately less intense cellular signal colocalized partially with the Golgi apparatus. In addition, kidneys from septic rats showed increased expression of CD14 and THP. They each colocalized strongly with TLR4, albeit in different tubular segments. We also imaged the kidneys of live septic animals with two-photon microscopy after fluorescent lipopolysaccharide (LPS) injection. Within 10 min, LPS was seen at the brush border of some proximal tubules. Within 60 min, LPS was fully cytoplasmic in proximal tubules. Conversely, distal tubules showed no LPS uptake. We conclude that TLR4, CD14, and THP have specific renal cellular and tubular expression patterns that are markedly affected by sepsis. Systemic endotoxin can freely access the tubular and cellular sites where these proteins are present. Therefore, locally expressed TLRs and other interacting proteins could potentially modulate the renal response to systemic sepsis.

Ca-dependent hemodynamic and natriuretic effects of atrial extract in isolated rat kidney

1984 ◽  
Vol 246 (4) ◽  
pp. F447-F456 ◽  
Author(s):  
M. J. Camargo ◽  
H. D. Kleinert ◽  
S. A. Atlas ◽  
J. E. Sealey ◽  
J. H. Laragh ◽  
...  
Keyword(s):  
Perfusion Pressure ◽  
Rat Kidney ◽  
Fractional Excretion ◽  
Electrolyte Excretion ◽  
Renal Vasculature ◽  
Filtration Fraction ◽  
Perfused Rat Kidney ◽  
Site Of Action ◽  
Initial Control ◽  
Renal Vascular

The effects of rat atrial tissue extract on renal hemodynamics and fluid and electrolyte excretion were investigated in the isolated perfused rat kidney (IK). IK were perfused at a constant effective perfusion pressure of about 90 mmHg. After control clearance periods (C), extracts of rat atria (AE) or ventricles (VE) were added to the perfusate and three 10-min experimental periods followed. AE, but not VE, significantly increased (P less than 0.001) renal vascular resistance (RVR) to 133 +/- 8% of C, GFR to 201 +/- 34%, filtration fraction to 245 +/- 41%, urine flow (V) to 675 +/- 131%, fractional excretion (FE) of H2O to 336 +/- 29%, absolute Na excretion (UNaV) to 1,259 +/- 290%, FENa to 642 +/- 129%, UKV to 2,226 +/- 1,237%, and FEK to 542 +/- 119%. Despite the marked natriuresis, since GFR doubled, Na reabsorption rose from 78.3 +/- 36.3 in C to 132 +/- 36.3 mueq/min after AE. The effects of AE were immediate and lasted to the end of the perfusion. The lower the initial control GFR, the larger was the AE-induced increase in GFR. Perfusion with low [Ca] (0.2 mM) or verapamil (10(-5) M) severely blunted the hemodynamic, diuretic, kaliuretic, and natriuretic effects of AE. AE decreased rather than increased the RVR when IK were perfused with vasoconstrictors such as angiotensin II, norepinephrine, or vasopressin. The results demonstrate that AE acts directly on the kidney, eliciting powerful Ca-dependent hemodynamic and natriuretic responses. The natriuresis induced by AE can be accounted for, at least in part, by its renal hemodynamic effects rather than by the presence of a putative tubular natriuretic factor. The hypothesis is advanced that AE contains a substance(s) which behaves as a functional agonist/antagonist of endogenous vasoconstrictors with a preferential site of action on the efferent arterioles of the renal vasculature.

scholarly journals Negative dialectic and linguistic turn: The actuality of Adorno’s concept of the conflict nature of modern societies

2010 ◽  
Vol 21 (2) ◽  
pp. 29-52
Author(s):  
Marjan Ivkovic
Keyword(s):  
Critical Theory ◽  
First Generation ◽  
Social Conflict ◽  
Frankfurt School ◽  
Linguistic Turn ◽  
Dead End ◽  
Negative Dialectic ◽  
Key Aspects ◽  
Insight Into ◽  
Crucial Characteristic

The author attempts at questioning Habermas? and Honneth?s claim that the linguistic turn within Critical Theory of society represents a way out of the ?dead end? of the first generation of Frankfurt School theorists, who were unable to formulate an action-theoretic understanding of social conflicts. By presenting a view that Adorno, in his ?Negative dialectic?, develops an insight into a crucial characteristic of the conflict nature of modern societies, which eludes the lingustic-pragmatist Critical Theory, the author tries to defend and reactualize Adorno?s perspective. The paper analyzes some key aspects of the original idea of Critical Theory, and the ?negativistic turn? that Adorno and Horkheimer made with the writing of ?Dialectic of Enlightenment?. Having considered the central arguments of the ?Negative Dialectic?, the author presents his understanding of Adorno?s concept of social conflict, which is then being contrasted with Habermas? understanding of social conflict, formulated in terms of a systemic colonization of the lifeworld. Pointing out the weaknesses of Habermas? concept, the author aims at sharpening the image of the conflict nature of modern societies that Adorno sketches, concluding that his perspective is able to question the framework of intersubjectivity that Habermas and Honneth take for granted.

scholarly journals Exploring the Role of Mesenchymal Stem Cells During Normothermic Organ Perfusion: A New Paradigm to Enhance Outcome Following Allograft Transplantation

2018 ◽  
Vol 5 (1) ◽  
pp. 47-52
Author(s):  
Mohamed Morsy ◽  
Mohammad Ayaz Hossain ◽  
Atul Bagul
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Organ Transplantation ◽  
Ex Vivo ◽  
Solid Organ Transplantation ◽  
Short Review ◽  
Solid Organ ◽  
New Paradigm ◽  
Liver And Kidney

Background: Normothermic Machine Perfusion (NMP) has been established in the field of solid organ transplantation for both liver and kidney allografts. The ability to perfuse organs at body temperature enables viability assessment as well as optimisation prior to implantation. Discussion: A recent in vitro report of the use of Mesenchymal Stem Cells (MSCs) in the use of a normothermic lung perfusion circuit has raised the possibility of their use in solid organ transplantation. The aim of this short review is to outline the potential uses of bone marrow derived MSCs for their use in renal allograft ex vivo NMP. An overview is provided of current literature of NMP as well as theorised uses for MSCs.

scholarly journals Protective effect of zinc-N-acetylcysteine on the rat kidney during cold storage

2013 ◽  
Vol 305 (7) ◽  
pp. F1022-F1030 ◽  
Author(s):  
Mandeep Singh ◽  
Dolapo T. Odeniyi ◽  
Eugene O. Apostolov ◽  
Alena Savenka ◽  
Todd Fite ◽  
...  
Keyword(s):  
Cell Death ◽  
Dna Fragmentation ◽  
Cold Storage ◽  
Ex Vivo ◽  
Rat Kidney ◽  
Maximum Effect ◽  
Kidney Preservation ◽  
Endonuclease G ◽  
Normal Rat ◽  
Rat Kidneys

Cold storage of kidneys before transplantation is problematic because of the limited survival time of the allografts. In this study, zinc- N-acetylcysteine (ZnNAC) was shown to be a potent endonuclease inhibitor and antioxidant, and it was tested as a potential additive to a cold storage solution for kidney preservation. Exposure of normal rat kidney NRK-52E cells to ZnNAC resulted in zinc delivery to the cells as determined by TFL-Zn fluorophore and partial protection of the cells against injury by cold storage in University of Wisconsin solution (UWS) as measured by propidium iodide assay. Ex vivo, rat kidneys demonstrated time- and temperature-dependent DNA fragmentation as assessed by TUNEL assay, indicating irreversible cell death. DNA fragmentation was faster in the medulla than in the cortex, and tubules were affected more than glomeruli. Perfusion of rat kidneys with cold ZnNAC solution in UWS significantly inhibited cell death both in the cortex and medulla at concentrations of 0.3–30 mM compared with UWS alone, with a maximum effect at 1–10 mM ZnNAC. Cold storage of the kidney significantly increased quantities of cleaved caspase-3 and endonuclease G (EndoG) in the tissue, which were abolished by 10 mM ZnNAC, indicating its ability to suppress both caspase-dependent and -independent cell death. Therefore, supplementation of UWS with ZnNAC can decrease DNA fragmentation and protect kidney allografts from cell death due to cold storage.

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