SBIR-STTR Award

Organ transplantation is one of the great success stories of modern medicine. However, the supply of suitable organs lags far behind the need and many patients die while waitlisted for organs. While there have been many recent strides in organ procurement, preservation and follow-up immune suppression, prevention of ischemia-reperfusion injury (IRI) remains problematic. IRI occurs when the ischemic/hypoxic organ is connected to the recipient's circulation. This storm of reactive oxygen species, inflammatory mediators and prothombotic factors damages the new organ and wreaks havoc upon the recipient as well. Current work indicates that enhancing the beneficial, low levels of nitric oxide (NO) produced by eNOS and nNOS can dramatically improve IRI and transplant outcomes. The founders of Vasculox have discovered a ligand-receptor system, thrombospondin-1 (TSP1) and CD47, that continually opposes the action of beneficial NO in all vascular cells. Knocking out CD47 in mice or blocking CD47 with a monoclonal antibody (mAb) results in enhanced tissue perfusion in a number of surgical ischemia models and substantial protection in models of liver and hindlimb IRI. Further, our initial studies in an ex vivo rat liver machine perfusion system support the efficacy of anti- CD47 therapy for IRI. In this phase one proposal, we seek to perform proof of concept studies in a well-characterized in vivo model of rat kidney transplantation. In Aim 1, we will test the efficacy of anti-CD47 mAb treatment of the donor kidney during cold ischemia to protect it from IRI. Preliminary studies indicate that the anti-CD47 mAb can be administered in the cold preservation medium flush at organ harvest. Aim 2 will determine if parenteral anti-CD47 mAb treatment of the recipient (in addition to pretreatment of the donor kidney) will further improve transplant outcomes. In both aims, readouts of kidney function (urine production, creatinine, BUN and soluble enzyme release) and cytokine levels will be monitored. Cyclic GMP levels in kidneys and plasma nitrite levels will be determined to confirm the mechanism of anti-CD47 mAb action in this model. The data obtained in this phase I project will establish proof of concept for anti-CD47 mAb therapy in kidney transplantation.

Public Health Relevance:
The founders of Vasculox Inc, have discovered a regulatory receptor, CD47, that inhibits nitric oxide signaling in all vascular tissues. Nitric oxide provides many beneficial effects in the vascular system, including limiting ischemia-reperfusion injury. Therefore blocking CD47 and preventing nitric oxide inhibition improves ischemia-reperfusion injury and holds promise as a means to improve the condition of organs destined for transplant and to control the damage to the recipient caused by ischemia reperfusion injury. Vasculox is developing a monoclonal antibody that targets CD47 and in this project aims to test the efficacy of such an antibody in an animal model of kidney transplantation. This will provide critical proof of concept for development of a humanized anti-CD47 antibody for use in organ transplantation thereby improving the outcome for all transplant recipients and expanding the number of organs available for transplantation.

Thesaurus Terms:
2-Amino-1,5-Dihydro-1-Methyl-4h-Imidazol-4-One;Abscission;Accounting;Active Follow-Up;Active Oxygen;Animal Model;Animal Models And Related Studies;Anti-Inflammatories;Anti-Inflammatory Agents;Anti-Inflammatory;Antibodies;Antigenic Surface Determinant Protein Oa3 Gene;Antiinflammatories;Antiinflammatory Agents;Apoplexy;Apoptosis;Apoptosis Pathway;Apoptotic;Bile;Bile Juice;Bile Fluid;Binding;Binding (Molecular Function);Bioavailability;Biologic Availability;Biologic Preservation;Biological Availability;Biological Preservation;Blood Circulation;Blood Plasma;Blood Vessels;Blood Flow;Bloodstream;Body Tissues;Brain Vascular Accident;Brush Border;Cd47;Cd47 Antigen (Rh-Related Antigen, Integrin-Associated Signal Transducer) Gene;Cd47 Glycoprotein Gene;Cd47 Gene;Cancers;Cardiac Death;Cardiac Infarction;Cell Communication And Signaling;Cell Signaling;Cells;Cerebral Stroke;Cerebrovascular Apoplexy;Cerebrovascular Stroke;Circulation;Circulatory Collapse;Clinical Treatment Moab;Clinical Trials;Clinical, Transplantation, Organ;Common Rat Strains;Creatinine;Cryofixation;Cryopreservation;Cyclic Gmp;Data;Deoxyguanylate Cyclase;Development;Dialysis;Dialysis Procedure;Disease;Disorder;Dose;Ec 1.14.13.39;Edrf Synthase;Endogenous Nitrate Vasodilator;Endothelium-Derived Growth Factor Synthase;Endothelium-Derived Nitric Oxide;Enzymes;Evaluation;Excision;Extirpation;Flushing;Gtp Pyrophosphate-Lyase (Cyclizing);Gases;Genetic;Goals;Grafting Procedure;Guanosine Cyclic 3',5'-Monophosphate;Guanosine Cyclic Monophosphate;Guanosine, Cyclic 3',5'-(Hydrogen Phosphate);Guanyl Cyclase;Guanylate Cyclase;Guanylyl Cyclase-Activating Factor Synthase;Harvest;Heart;Hindlimb;Human;Hypoxia;Hypoxic;Iap Gene;Ice;Immunosuppression Effect;Immunosuppressions (Physiology);Immunosuppressive Effect;Inflammation;Inflammation Mediators;Inosinate Cyclase;Integrin-Associated Protein Gene;Intestinal;Intestines;Intracellular Communication And Signaling;Ischemia;Ischemia-Reperfusion Injury;Kidney;Kidney Grafting;Kidney Transplantation;Kidney Transplants;Kidney Tubules;Kidney Urinary System;Knock-Out;Knockout;Loinc Axis 4 System;Leukocyte Surface Antigen Cd47 Gene;Life;Ligands;Liver;Lung;Lung Respiratory System;Mer6 Gene;Malignant Neoplasms;Malignant Tumor;Man (Taxonomy);Mice;Mice Mammals;Modeling;Modern Man;Modern Medicine;Molecular Interaction;Monitor;Monoclonal Antibodies;Monoclonal Antibody Therapy;Mononitrogen Monoxide;Murine;Mus;Myocardial Infarct;Myocardial Infarction;Nadph-Diaphorase;No Synthase;Natural Immunosuppression;Nitric Oxide;Nitric Oxide Donors;Nitric Oxide Synthase;Nitric-Oxide Synthetase;Nitrites;Nitrogen Monoxide;Nitrogen Protoxide;Oa3 Gene;Operative Procedures;Operative Surgical Procedures;Organ;Organ Donor;Organ Harvestings;Organ Procurements;Organ Transplantation;Organ Transplants;Organ Transplants, Including Bone Marrow For Dct;Outcome;Oxidative Burst;Oxygen Deficiency;Oxygen Radicals;Patients;Perfusion;Phase;Physiologic Availability;Plasma;Plasma Serum;Prevention;Pro-Oxidants;Procedures;Production;Programmed Cell Death;Rat;Rats Mammals;Rattus;Reactive Oxygen Species;Receptor Protein;Removal;Renal Transplantation;Renal Transplants;Renal Function;Renal Tubule Structure;Reperfusion Damage;Reperfusion Injury;Reperfusion Therapy;Respiratory Burst;Reticuloendothelial System, Serum, Plasma;Risk;Shock;Signal Transduction;Signal Transduction Systems;Signaling;Social Support System;Solid;Staging;Stress;Striated Border;Support System;Surface Antigen Identified By Monoclonal Antibody 1d8 Gene;Surgical;Surgical Interventions;Surgical Procedure;Surgical Removal;System;Tsp-1;Tsp1;Therapeutic;Thrombosis;Thrombospondin 1;Tissues;Transplant Recipients;Transplantation;Transplantation Surgery;Trauma;Urine;Urine Urinary System;Vascular System;Vascular Blood Supply;Vascular Constriction (Function);Vasoconstriction;Vasodilatation;Vasodilation;Vasorelaxation;Warm Ischemia;Work;Base;Biological Signal Transduction;Blood Supply;Bowel;Brain Attack;Cgmp;Cardiac Infarct;Cerebral Vascular Accident;Cerebrovascular Accident;Circulatory Shock;Clinical Investigation;Cold Preservation;Cold Storage;Coronary Attack;Coronary Infarct;Coronary Infarction;Cytokine;Developmental;Dialysis Therapy;Disease/Disorder;Efficacy Testing;Endothelial Cell Derived Relaxing Factor;Follow Up;Follow-Up;Followed Up;Graft Function;Guanosine 3'5'monophosphate;Guanylyl Cyclase;Heart Attack;Heart Infarct;Heart Infarction;Hepatic Body System;Hepatic Organ System;Ino;Immune Suppression;Immunosuppression;Improved;In Vivo;In Vivo Model;Indexing;Inflammatory Mediator;Inhaled Nitric Oxide;Kidney Function;Leukocyte Oxidative Burst;Malignancy;Meetings;Model Organism;Neoplasm/Cancer;Organ Allograft;Organ Graft;Organ Xenograft;Preservation;Prevent;Preventing;Pulmonary;Receptor;Renal;Renal Tubule;Reperfusion;Resection;Respiratory Burst (Leukocyte);Soft Tissue;Stroke;Success;Surgery;Transplant;Transplant Patient;Vascular;Vascular Supply

Organ transplantation is a lifesaving option for those with end stage renal disease. In spite of many improvements in organ procurement, transplant procedures and immune suppression, the damage done by ischemia-reperfusion injury (IRI) remains problematic, leading to primary graft nonfunctional, delayed graft function and graft failure. The critical shortage of donor kidneys has increased the use of expanded criteria organs (ECD) and donation after cardiac death (DCD) organs that are even more susceptible to IRI damage. Thus reducing IRI will not only improve the success rate of standard criteria (SCD) organs, but may also allow greater use of ECD and DCD organs, thus increasing the number of transplants that can be performed and lives that can be saved. Enhanced nitric oxide (NO) signaling can benefit preservation of kidneys during transport and alleviate IRI upon transplantation. However, the founders of Vasculox discovered that thrombospondin-1 (TSP1) binding to its receptor, CD47, limits NO signaling throughout the vascular system thereby worsening IRI. Blocking the TSP1-CD47 system with anti-CD47 monoclonal antibodies (CD47mAbs) dramatically improves outcomes in models of kidney, liver, brain, hindlimb and soft tissue IRI. In our Phase I grant period, we have shown that treatment of harvested rat kidneys with CD47mAbs prior to 6 hr. of cold ischemia provides substantial protection against histological damage and improves markers of both kidney damage and function. Most significantly, treatment of donor kidneys with a CD47mAb also enhances survival of the recipient. Vasculox has successfully humanized a CD47mAb (CD47humAb) for use in transplantation that has the unique property of binding to many species including rodent, pig and human. Here we will to test the CD47humAb in both small (rat) and large (pig) animal models of kidney transplantation. Our specific aims are: Aim 1. Rat kidney SCD and DCD transplants. 1A. Determine in a syngeneic transplant model if kidneys subjected to warm ischemic times to mimic DCD kidneys can be rescued by treating the donor kidney and/or recipient with CD47humAb. 1B. Test the efficacy of the CD47humAb in an allogeneic (Brown Norway to Lewis) rat kidney transplant model with the use of an immunosuppressive drug (tacrolimus) under SCD and DCD conditions to mimic the mismatch that occurs with human donors/recipients. Aim 2. Porcine kidney DCD transplants. Determine if CD47humAb therapy can improve the performance of kidneys subjected to a period of warm ischemia to mimic the transplantation of marginal DCD kidneys. Dr. Douglass Hanto, who developed this model in pigs, is our consultant for this study. Following his protocol, we will introduce a 60 minute warm ischemic time prior to harvest and cold storage to mimic human DCD kidney transplantation. This will establish proof of concept for CD47humAb treatment in a large animal model for the use of marginal organs that are more susceptible to IRI and therefore worse transplant outcomes.

Public Health Relevance Statement:


Public Health Relevance:
The founders of Vasculox, Inc. have discovered a regulatory receptor, CD47 that inhibits nitric oxide signaling in all vascular tissues. Nitric oxide provides many beneficial effects in the vascular system, including limiting ischemia-reperfusion injury that occurs during organ transplantation. Therefore, blocking CD47 and preventing nitric oxide inhibition improves ischemia-reperfusion injury and holds promise as a means to improve the condition of organs destined for transplant and to control the damage to the recipient caused by ischemia-reperfusion injury. Vasculox has developed a humanized monoclonal antibody that targets CD47 and in this project aims to test the efficacy of such an antibody in animal models of kidney transplantation that reflect the situation of the human transplant patient. This will advance our humanized CD47mAb toward our goal of FDA approval for kidney transplantation thereby improving outcomes for all transplant recipients and allowing the use of "marginal" kidneys thereby expanding the number of organs available for transplantation and the number of lives that can be saved.

NIH Spending Category:
Kidney Disease; Organ Transplantation; Transplantation

Project Terms:
Address; Allogenic; Animal Model; Antibodies; Apoptosis; Binding (Molecular Function); Biological Availability; Blood Vessels; Brain; Cardiac Death; CD47 gene; Cell Death; cGMP production; Clinical Research; Cryopreservation; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Data; delayed graft function; Development; Dialysis procedure; Drug Kinetics; efficacy testing; End stage renal failure; Family suidae; Gases; Goals; graft failure; Grant; Guanylate Cyclase; Harvest; Hindlimb; Human; humanized monoclonal antibodies; Immunosuppressive Agents; improved; Inflammation; inhaled nitric oxide; Ischemia; Kidney; kidney preservation; Kidney Transplantation; Life; Ligands; Liver; Mitochondria; Modeling; Monoclonal Antibodies; Natural immunosuppression; Necrosis; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Norway; Organ; Organ Donations; Organ Donor; Organ Procurements; Organ Transplantation; Outcome; Patients; Performance; Pharmaceutical Preparations; Phase; phase 2 study; pre-clinical; preclinical study; prevent; Procedures; Production; Property; Protocols documentation; public health relevance; Rattus; receptor; Reperfusion Injury; research study; Rodent; Safety; Signal Transduction; soft tissue; Stress; success; System; Tacrolimus; Testing; Therapeutic immunosuppression; Thrombosis; Thrombospondin 1; Time; Tissues; Translating; Transplant Recipients; Transplantation; Vascular blood supply; Vascular constriction (function); Vascular System; Warm Ischemia