Adenine Induced Anemia In Rats

Induction: 

Animals will be randomized on day 0 into groups by body weight and then placed on an adenine enriched (0.75%) diet for a period up to 2-3 weeks, followed by a 0.1 to 0.3% for 5-6 weeks for a total of 8 weeks in duration.  Animals will have baseline clinical pathology done as baseline measurements prior to diet administration on day zero, just prior to switching out the normal chow with the adenine diet.  

Disease Parameters/Progression: 

Animals will then be monitored for changes in body weight, clinical pathology and/or urine protein at regular intervals (every 1-2 weeks) throughout the study.  Animals will be monitored for clinical observations and criteria for early termination will be based on IACUC allowable body weight loss or clinical observations (daily clinical observations will only be done in pilot studies).  Additionally, the use of clinical pathology will allow the removal of an animal which has a hemoglobin concentration <7g/dL, a sign of severe anemia or urine protein excretion >2000mg/dL, a sign of no filtration by the glomeruli.

Dosing Paradigms:

Route of administration: SC, PO, IP, IV

Clinical Assessment:

Adenine diet will induce kidney inflammation, fibrosis, renal failure and anemia.  There should not be any specific pain associated with the disease process, but the resulting anemia can involve stress related to fatigue.  The anemia and kidney failure will be monitored with clinical pathology, body weights, and clinical observations of the animals.   The model will not be done as a survival study, if it is deemed the effects of the diets are too extreme, concentrations of adenine or study length will be amended to avoid severe effects.

Any animals that lose more than 20% body weight within 1 week will be enrolled in the animal health assessment program and monitored daily. Animals that lose more than 30% of their body weight from the start of a study will be euthanized.

Histopathological Assessment: 

Sample Data (Click on Image to Enlarge):

Rat Clinical

Notes:

Anemia of chronic disease (ACD) and iron deficiency anemia (IDA) are characterized by macrophage iron retention induced by cytokines and blood loss(3). ACD has been previously induced in rats upon administration of dietary adenine and used to study anemia related to inflammatory and chronic diseases(3). By inducing anemia in the Wistar rats in this study, we will have a model which may be useful in discovering future treatments for anemia.

Adenine is the nucleotide part of the make-up of DNA. When adenine is ingested at large concentrations it can crystalize in the proximal tubules of the kidney, leading to nephritis and eventual renal failure (1-3). The process would be similar to what may be seen in human kidney crystalopathies, which can be caused by calcium oxalate, uric acid, struvite, or cysteine crystals. Erythropoietin (EPO) is produced in the kidney and is necessary stimulatory factor for ethryropoiesis. As the kidney loses function EPO production decreases which can result in mild to moderate anemia.  Severity of anemia and kidney damage is dependent upon the dose of adenine used, however the resulting anemia is typically mild to moderate in severity.

Optional Endpoint

  • PK/PD blood collections
  • Cytokine/chemokine analysis via Luminex(R)
  • Other sandwich ELISAs
  • CBC/clinical chemistry analysis
  • Soft tissue collection
  • Histopathologic analysis
  • Immunohistochemistry analysis

References

  1. Ali BH, Adham SA,  Al Za’abi M, Waly MI, Yasin J, Nemmar, A, Schupp N.  Ameliorative Effect of Chrysin on Adenine-Induced Chronic Kidney Disease in Rats.  Plos One.   2015; 10.1371:1-14.
  2. Sun CC, Vaja V, Chen S, Theurl I, Stepanek A, Brown DE, CAppelline MD, Weiss G, Hong CC, Lin HY, Babitt JL.  A hepcidin lowering agent mobilizes iron for incorporation into red blood cells in an adenine-induced kidney disease model of anemia in rats.  Nephol Dial Transplant (2013)28:  1733-1743.
  3. Za’abi MA, Busaidi MA, Yasin J, Schupp N, Nemmar A, Ali BH.  Development of a new model for the induction of chronic kidney disease vi intraperitoneal adenine administration and the effect of treatment with gum acacia theron.  Am J Transl Res.  (2015) 7(1):28-38

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