DP1DK130660

Defining the Lymphatic Basis of Protein Losing Enteropathy after Fontan Palliation or Inflammatory Gut Disease - Abstract

Protein-losing enteropathy (PLE) is the term given to the pathological phenomenon of protein dumping from the systemic circulation into the intestinal lumen. Various degrees of PLE are observed in a variety of otherwise unrelated diseases. For instance, PLE is a complication of the life-saving Fontan palliation procedure performed on children born with only a single ventricle of the heart to create a vascular diversion to the lungs to promote improved oxygenation of blood. Fontan-associated PLE is linked with high mortality: 30-50% over 5- to 10-years. Yet, PLE remains understudied.

The dominant causal mechanisms underlying PLE appear to relate to (1) loss of barrier integrity at the intestinal epithelium or (2) functional disturbance of the lymphatic vasculature. Intestinal epithelial cell erosion would expose proteinaceous tissue fluid to the intestinal lumen. Furthermore, poor epithelial intercellular junctions might allow for the contents of the lamina propria interstitium to leak into the intestinal lumen. With respect to lymphatics, failure of lymph to flow away from the intestine uni-directionally toward the heart and instead to flow backwards from the body trunk toward the intestine with sufficient force to break across the epithelium may be a major cause of PLE.

The literature presents Fontan palliation-associated PLE as a problem driven by lymphatic backflow, whereas PLE in IBD (such as Crohn's disease) is presented as being of mixed etiology that involves breach of epithelial integrity with possible additional contributions stemming from lymphatic dysfunction. However, it is acknowledged in the literature that the full basis of PLE in any of these conditions is uncertain and that there are several reasons why the current explanations may be questioned.

We will carry out focused research on PLE that includes studies involving human participants as well as studies in experimental animal models. Our hypotheses are, first, that the lymphatic vasculature is a primary player in PLE affecting Fontan patients and IBD patients, and second, that the lymphatic vasculature must receive "two hits" to drive sufficient backflow of lymph to cause outflow from the intestinal barrier. The first of these hits has already been considered (but not completely tested) in the context of Fontan palliation: increased pressure within the chain of lymphangions (vessel units between lymphatic valves). We propose this second hit is an inflammatory signal that negatively affects lymphatic valves.

The two-hit model may resolve a confusing observation in Fontan patients with PLE wherein treatments with steroids like budesonide can be effective. A steroid seems unlikely to strongly alter pressure in the venous and lymphatic systems, but it is easy to envision how steroids may help by reducing adverse inflammatory signaling associated with valve failure. If this model is correct, a path to therapies not previously considered to treat PLE may become evident.

Washington University

(1) TO PROMOTE EXTRAMURAL BASIC AND CLINICAL BIOMEDICAL RESEARCH THAT IMPROVES THE UNDERSTANDING OF THE MECHANISMS UNDERLYING DISEASE AND LEADS TO IMPROVED PREVENTIONS, DIAGNOSIS, AND TREATMENT OF DIABETES, DIGESTIVE, AND KIDNEY DISEASES. PROGRAMMATIC AREAS WITHIN THE NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES INCLUDE DIABETES, DIGESTIVE, ENDOCRINE, HEMATOLOGIC, LIVER, METABOLIC, NEPHROLOGIC, NUTRITION, OBESITY, AND UROLOGIC DISEASES. SPECIFIC PROGRAMS AREAS OF INTEREST INCLUDE THE FOLLOWING: (A) FOR DIABETES, ENDOCRINE, AND METABOLIC DISEASES AREAS: FUNDAMENTAL AND CLINICAL STUDIES INCLUDING THE ETIOLOGY, PATHOGENESIS, PREVENTION, DIAGNOSIS, TREATMENT AND CURE OF DIABETES MELLITUS AND ITS COMPLICATIONS, NORMAL AND ABNORMAL FUNCTION OF THE PITUITARY, THYROID, PARATHYROID, ADRENAL, AND OTHER HORMONE SECRETING GLANDS, HORMONAL REGULATION OF BONE, ADIPOSE TISSUE, AND LIVER, ON FUNDAMENTAL ASPECTS OF SIGNAL TRANSDUCTION, INCLUDING THE ACTION OF HORMONES, COREGULATORS, AND CHROMATIN REMODELING PROTEINS, HORMONE BIOSYNTHESIS, SECRETION, METABOLISM, AND BINDING, AND ON HORMONAL REGULATION OF GENE EXPRESSION AND THE ROLE(S) OF SELECTIVE RECEPTOR MODULATORS AS PARTIAL AGONISTS OR ANTAGONISTS OF HORMONE ACTION, AND FUNDAMENTAL STUDIES RELEVANT TO METABOLIC DISORDERS INCLUDING MEMBRANE STRUCTURE, FUNCTION, AND TRANSPORT PHENOMENA AND ENZYME BIOSYNTHESIS, AND BASIC AND CLINICAL STUDIES ON THE ETIOLOGY, PATHOGENESIS, PREVENTION, AND TREATMENT OF INHERITED METABOLIC DISORDERS (SUCH AS CYSTIC FIBROSIS). (B) FOR DIGESTIVE DISEASE AND NUTRITION AREAS: GENETICS AND GENOMICS OF THE GI TRACT AND ITS DISEASES, GENETICS AND GENOMICS OF LIVER/PANCREAS AND DISEASES, GENETICS AND GENOMICS OF NUTRITION, GENETICS AND GENOMICS OF OBESITY, BARIATRIC SURGERY, CLINICAL NUTRITION RESEARCH, CLINICAL OBESITY RESEARCH, COMPLICATIONS OF CHRONIC LIVER DISEASE, FATTY LIVER DISEASE, GENETIC LIVER DISEASE, HIV AND LIVER, CELL INJURY, REPAIR, FIBROSIS AND INFLAMMATION IN THE LIVER, LIVER CANCER, LIVER TRANSPLANTATION, PEDIATRIC LIVER DISEASE, VIRAL HEPATITIS AND INFECTIOUS DISEASES, GASTROINTESTINAL AND NUTRITION EFFECTS OF AIDS, GASTROINTESTINAL MUCOSAL AND IMMUNOLOGY, GASTROINTESTINAL MOTILITY, BASIC NEUROGASTROENTEROLOGY, GASTROINTESTINAL DEVELOPMENT, GASTROINTESTINAL EPITHELIAL BIOLOGY, GASTROINTESTINAL INFLAMMATION, DIGESTIVE DISEASES EPIDEMIOLOGY AND DATA SYSTEMS, NUTRITIONAL EPIDEMIOLOGY AND DATA SYSTEMS, AUTOIMMUNE LIVER DISEASE, BILE, BILIRUBIN AND CHOLESTASIS, BIOENGINEERING AND BIOTECHNOLOGY RELATED TO DIGESTIVE DISEASES, LIVER, NUTRITION AND OBESITY, CELL AND MOLECULAR BIOLOGY OF THE LIVER, DEVELOPMENTAL BIOLOGY AND REGENERATION, DRUG-INDUCED LIVER DISEASE, GALLBLADDER DISEASE AND BILIARY DISEASES, EXOCRINE PANCREAS BIOLOGY AND DISEASES, GASTROINTESTINAL NEUROENDOCRINOLOGY, GASTROINTESTINAL TRANSPORT AND ABSORPTION, NUTRIENT METABOLISM, PEDIATRIC CLINICAL OBESITY, CLINICAL TRIALS IN DIGESTIVE DISEASES, LIVER CLINICAL TRIALS, OBESITY PREVENTION AND TREATMENT, AND OBESITY AND EATING DISORDERS. (C) FOR KIDNEY, UROLOGIC AND HEMATOLOGIC DISEASES AREAS: STUDIES OF THE DEVELOPMENT, PHYSIOLOGY, AND CELL BIOLOGY OF THE KIDNEY, PATHOPHYSIOLOGY OF THE KIDNEY, GENETICS OF KIDNEY DISORDERS, IMMUNE MECHANISMS OF KIDNEY DISEASE, KIDNEY DISEASE AS A COMPLICATION OF DIABETES, EFFECTS OF DRUGS, NEPHROTOXINS AND ENVIRONMENTAL TOXINS ON THE KIDNEY, MECHANISMS OF KIDNEY INJURY REPAIR, IMPROVED DIAGNOSIS, PREVENTION AND TREATMENT OF CHRONIC KIDNEY DISEASE AND END-STAGE RENAL DISEASE, IMPROVED APPROACHES TO MAINTENANCE DIALYSIS THERAPIES, BASIC STUDIES OF LOWER URINARY TRACT CELL BIOLOGY, DEVELOPMENT, PHYSIOLOGY, AND PATHOPHYSIOLOGY, CLINICAL STUDIES OF BLADDER DYSFUNCTION, INCONTINENCE, PYELONEPHRITIS, INTERSTITIAL CYSTITIS, BENIGN PROSTATIC HYPERPLASIA, UROLITHIASIS, AND VESICOURETERAL REFLUX, DEVELOPMENT OF NOVEL DIAGNOSTIC TOOLS AND IMPROVED THERAPIES, INCLUDING TISSUE ENGINEERING STRATEGIES, FOR UROLOGIC DISORDERS,RESEARCH ON HEMATOPOIETIC CELL DIFFERENTIATION, METABOLISM OF IRON OVERLOAD AND DEFICIENCY, STRUCTURE, BIOSYNTHESIS AND GENETIC REGULATION OF HEMOGLOBIN, AS WELL AS RESEARCH ON THE ETIOLOGY, PATHOGENESIS, AND THERAPEUTIC MODALITIES FOR THE ANEMIA OF INFLAMMATION AND CHRONIC DISEASES. (2) TO ENCOURAGE BASIC AND CLINICAL RESEARCH TRAINING AND CAREER DEVELOPMENT OF SCIENTISTS DURING THE EARLY STAGES OF THEIR CAREERS. THE RUTH L. KIRSCHSTEIN NATIONAL RESEARCH SERVICE AWARD (NRSA) FUNDS BASIC AND CLINICAL RESEARCH TRAINING, SUPPORT FOR CAREER DEVELOPMENT, AND THE TRANSITION FROM POSTDOCTORAL BIOMEDICAL RESEARCH TRAINING TO INDEPENDENT RESEARCH RELATED TO DIABETES, DIGESTIVE, ENDOCRINE, HEMATOLOGIC, LIVER, METABOLIC, NEPHROLOGIC, NUTRITION, OBESITY, AND UROLOGIC DISEASES. (3) TO EXPAND AND IMPROVE THE SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM. THE SBIR PROGRAM AIMS TO INCREASE AND FACILITATE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, TO ENHANCE SMALL BUSINESS PARTICIPATION IN FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. (4) TO UTILIZE THE SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM. THE STTR PROGRAM INTENDS TO STIMULATE AND FOSTER SCIENTIFIC AND TECHNOLOGICAL INNOVATION THROUGH COOPERATIVE RESEARCH AND DEVELOPMENT CARRIED OUT BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO FOSTER TECHNOLOGY TRANSFER BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION.

93.847 - Diabetes, Digestive, and Kidney Diseases Extramural Research

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) [HHS - NIH]

Saint Louis, Missouri 631101010 United States

Single Zip Code

NIDDK Catalyst Award (DP1 Clinical Trial Not Allowed) (RFA-DK-20-024)

Amendment Since initial award the total obligations have increased 377% from $787,500 to $3,759,375.