PATHOPHYSIOLOGICAL EFFECTS OF RENAL ALLOGRAFTS IN THE DOG

Seven dogs with renal allografts were studied to: (1) determine the practicality of the procedure for the treatment of end stage kidney disease in small animal medicine, and (2) measure allograft function to permit evaluation of immunosuppressive drug dosage to prevent rejection. Infection (bacterial nephritis, pneumonia, pleuritis), drug toxicity (bone marrow depression, liver degeneration and/or necrosis), and rejection of the transplants were the consistent problems. No objective measurement which would permit accurate determination of immunosuppressive drug dosage was found. Polyuria in the transplanted animals was attributed to failure to develop the interstitial osmotic gradient essential for the allografts to respond to antidiuretic hormone. Polydipsia probably was compensation for the polyuria. The results would indicate that until a major immunological breakthrough occurs in tissue transplantation, the clinical placement of a renal allograft in the dog for long term function is not practical. Prolonged function of the renal allograft has been accomplished in the dog using immunosuppressive drugs, suggesting that the procedure can be utilized for the treatment of end stage renal disease in this animal.¹⁸ Immunosuppressive drugs have inherent toxicities, of which bone marrow depression, liver and gastrointestinal tract damage are most notable.^5,18,23 Ideally, minimal immunosuppression is desired to avoid drug toxicity, maintain some degree of immune competence to reduce chances of serious, if not fatal infection, and yet allow the transplanted kidney to survive in a hostile immune environment.²² There are no good measurements to determine the immunological status of patients on immunosuppressive therapy,²² consequently, such treatment is emperic; based on experimental and clinical experience. ^13,18 Although the dog is a common model for renal allograft investigations, ^15,18 there is limited information in the veterinary literature 3.5.6,11,14 concerning the experience of veterinary clinicians and their attempts to maintain the renal homograft. This report summarizes the author's experiment with renal transplants in the dog.