Chronic Renal Failure-Causes, Clinical Findings, Treatments and Prognosis.

Chronic kidney disease (CKD) is rare in horses with an overall prevalence reported to be 0.12%. There is often a continuum from Acute Kidney Injury (AKI) to CKD, and patients with CKD may be predisposed to episodes of AKI. The most common clinical signs are non-specific with weight loss, polyuria/polydipsia and ventral edema. Less common clinical signs are poor appetite and performance, dull hair coat, oral ulcerations, gastro-intestinal ulceration, gingivitis, dental tartar and diarrhea. Rarely, horses may develop forebrain signs. Creatinine increases when at least 2/3 of kidney function have been lost and a more accurate assessment of kidney function is an estimated glomerular filtration rate measuring iohexol clearance time combined with protein content in the urine. Tubulointerstitial disease and glomerulonephritis are common causes of chronic kidney disease together with pyelonephritis and nephrolithiasis. Dietary changes and avoiding nephrotoxic drugs are key in slowing down the degenerative process.

A Carrel patch technique for renal transplantation in cats.

OBJECTIVE: To evaluate the feasibility of a Carrel patch method in feline renal transplantation. STUDY DESIGN: Descriptive case series. ANIMALS: Nine healthy donor cats and 9 client recipient cats with chronic renal failure. METHODS: Renal transplantation was performed in 9 cats with chronic renal failure after collection of a donor's left kidney with a Carrel patch technique. A patch of donor aortic wall was removed with either 2 or 1 renal artery (ies) (n = 1 and 8 cats, respectively) central to the patch, with a cuff of tissue (≤1 mm) protruding from the base of the vessels. The Carrel patch was implanted in recipient cats with an end-to-side artery-to-aorta anastomosis, in a simple-continuous pattern of 9-0 nylon. The renal vein and ureter were implanted as previously described. RESULTS: All donors and recipients survived surgery without vascular complication. CONCLUSION: The Carrel patch is a novel approach allowing the harvest of kidneys with multiple renal arteries. The technique also simplified the implant procedure, potentially decreasing the risks of bleeding and thrombosis.

Ureteral Papilla Implantation as a Technique for Neoureterocystostomy in Cats Undergoing Renal Transplantation: 30 Cases.

OBJECTIVE: To describe the clinical outcome of donor and recipient cats undergoing ureteral papilla harvest and implantation as a technique for neoureterocystostomy in clinical kidney transplant. STUDY DESIGN: Retrospective case series. ANIMALS: Donor (n=31) and recipient (n=30) cats that underwent kidney harvest and transplantation using ureteral papilla implantation technique for neoureterocystostomy. METHODS: Medical records for donor and recipient cats presented to the University of Wisconsin Veterinary Teaching Hospital from January 2003 to December 2014 were reviewed. Data recorded included complete blood count, serum chemistry panel, surgical technique, diagnostic imaging results, short- and long-term complications, and anesthetic survival. RESULTS: All 30 recipients recovered from anesthesia. Four died within 24 hours and 26 survived to hospital discharge. Serum creatinine was within the reference interval by 72 hours in 22/26 cats (85%). Complications related to the ureteral papilla implantation technique were seen in only 1 cat (3%). Uroabdomen diagnosed on day 3 ultimately resolved over the following 24 hours without surgical intervention. All 31 donor cats survived to discharge. Four donors (13%) experienced mild, transiently increased serum creatinine. CONCLUSION: Ureteral papilla implantation is a viable technique for neoureterocystostomy in cats undergoing kidney transplantation. Proposed benefits for the recipient include a less technically challenging anastomosis, decreased risk of ureteral obstruction at the anastomosis site, and reduced risk of leakage compared to previous reports. Benefits for recipients should be weighed against risks to donors, including a more complex ureteral harvest, increased surgical time, and potential injury or obstruction of the contralateral ureteral papilla.

A retrospective study of end-stage renal disease in captive polar bears (Ursus maritimus).

This retrospective study summarizes 11 cases of end-stage renal disease (ESRD) in captive polar bears (Ursus maritimus) from eight zoologic institutions across the United States and Canada. Ten bears were female, one was male, and the mean age at the time of death was 24 yr old. The most common clinical signs were lethargy, inappetence, and polyuria-polydipsia. Biochemical findings included azotemia, anemia, hyperphosphatemia, and isosthenuria. Histologic examination commonly showed glomerulonephropathies and interstitial fibrosis. Based on submissions to a private diagnostic institution over a 16-yr period, ESRD was the most commonly diagnosed cause of death or euthanasia in captive polar bears in the United States, with an estimated prevalence of over 20%. Further research is needed to discern the etiology of this apparently common disease of captive polar bears.

Dilated ureters, renal dysplasia, and chronic renal failure in an African elephant (Loxodonta africana).

An ultrasonographic reproductive health examination of a 26-yr-old female African elephant (Loxodonta africana) revealed bilateral ureteral wall thickening and dilatation. On ultrasonographic examination, the bladder and both ureters were normal near the trigone; however, the cranial-most aspect of each ureter was dilated and thickened for a length of 30-50 cm. The same month, elevated blood creatinine (3.0 mg/dl), and urine protein-creatinine ratio (4.0) were observed. Chronic renal failure was diagnosed based on these abnormalities, and the persistent ureteral dilatation was seen on subsequent ultrasound examinations. Complete blood cell counts, serum chemistries, and urinalyses remained relatively unchanged until 24 mo after diagnosis, at which time azotemia, hypophosphatemia, and hypercalcemia (including elevated ionized calcium) developed. Hydronephrosis of both kidneys and prominent sacculation of the left ureter were noted on ultrasonographic examination. Lethargy, ventral edema, and oral mucosal ulceration acutely developed 30 mo after diagnosis. Although blood urea nitrogen remained elevated, creatinine, total calcium, and ionized calcium returned to within reference ranges at that time. Due to rapid clinical decline and grave prognosis, humane euthanasia was elected. Bilateral ureteral dilatation, dysplasia of the right kidney, and chronic nephritis of the left kidney were identified postmortem.

Metastatic calcinosis (including calcinosis cutis) in a young dog with multiple urinary tract abnormalities.

Metastatic calcinosis associated with chronic renal failure and multiple urinary tract abnormalities was diagnosed in a 6-month-old Brittany spaniel that was presented with calcinosis cutis. This case report highlights the importance of skin as an indicator of systemic disease. The aetiopathogenesis of the four main types of tissue calcification is defined and discussed with an emphasis on metastatic calcinosis.

Renal dysplasia in Beagle dogs: four cases.

Anomalies of renal development comprise abnormalities in the amount of renal tissue (agenesis and hypoplasia); anomalies of renal position, form, and orientation; and renal dysplasia. There are previous reports of canine renal dysplasia in different breeds but none in the Beagle breed. This is the first report of renal dysplasia in this breed of dog. Morphologic descriptions of the range of microscopic features observed in four cases of renal dysplasia from preclinical studies in laboratory Beagle dogs are presented (including persistent primitive mesenchyme, persistence of metanephric ducts, asynchronous differentiation of nephrons, and atypical tubular epithelium), along with a basis for the classification of the lesion.

Quantitative assessment of urea generation and elimination in healthy dogs and in dogs with chronic kidney disease.

BACKGROUND: Kinetic assessment of urea, the main end product of protein metabolism, could serve to assess protein catabolism in dogs with chronic kidney disease (CKD). Protein malnutrition and catabolism are poorly documented in CKD and they often are neglected clinically because of a lack of appropriate evaluation tools. HYPOTHESIS: Generation and excretion of urea are altered in dogs with CKD. ANIMALS: Nine dogs with spontaneous CKD (IRIS stages 2-4) and 5 healthy research dogs. METHODS: Endogenous renal clearance (Clrenal) of urea and creatinine was measured first. Exogenous plasma clearance (Clplasma, total body clearance) of the 2 markers then was determined by an IV infusion of urea (250-1,000 mg/kg over 20 minutes) and an IV bolus of creatinine (40 mg/kg). Extrarenal clearance (Clextra) was defined as the difference between Clplasma)and Clrenal. Endogenous urea generation was computed assuming steady-state conditions. RESULTS: Median Clrenal and Clextra of urea were 2.17 and 0.21 mL/min/kg in healthy dogs and 0.37 and 0.28 mL/min/kg in CKD dogs. The proportion of urea cleared by extrarenal route was markedly higher in dogs with glomerular filtration rate<1 mL/kg/min than in normal dogs, reaching up to 85% of the total clearance. A comparable pattern was observed for creatinine excretion, except in 1 dog, Clextra remained<20% of Clplasma. CONCLUSION: Extrarenal pathways of urea excretion are predominant in dogs with advanced CKD and justify exploring adjunctive therapies based on enteric nitrogen excretion in dogs. A trend toward increased urea generation may indicate increased catabolism in advanced CKD.

Correction of hyperkalemia in dogs with chronic kidney disease consuming commercial renal therapeutic diets by a potassium-reduced home-prepared diet.

BACKGROUND: Hyperkalemia occurs in dogs with chronic kidney disease (CKD). OBJECTIVES: (1) To determine the incidence of hyperkalemia in dogs with CKD, (2) to determine the proportion of hyperkalemic dogs that required modification of dietary potassium intake, (3) to evaluate the response to dietary modification. METHODS: The hospital database was reviewed retrospectively to identify dogs with CKD and persistent (>5.3 mmol/L on at least 3 occasions) or severe (K > or = 6.5 mmol/L) hyperkalemia while consuming a therapeutic renal diet. Records of dogs with hyperkalemia that were prescribed a home-prepared, potassium-reduced diet were evaluated further. Response was evaluated by changes in body weight, BCS, and serum potassium concentration. RESULTS: One hundred and fifty-two dogs were diagnosed with CKD, of which 47% had > or =1 documented episode of hyperkalemia, 25% had > or = 3 episodes of hyperkalemia, and 16% had > or =1 episodes of severe hyperkalemia (K > 6.5 mmol/L). Twenty-six dogs (17.2%) with CKD and hyperkalemia were prescribed a potassium-reduced, home-prepared diet. The potassium concentration of all hyperkalemic dogs on therapeutic diets (potassium content, 1.6 +/- 0.23 g/1,000 kcal of metabolizable energy [ME]) was 6.5 +/- 0.5 mmol/L but decreased significantly to 5.1 +/- 0.5 mmol/L in 18 dogs available for follow-up in response to the dietary modification (0.91 +/- 0.14 g/1,000 kcal of ME, P < .001). Potassium concentration normalized in all but 1 dog. CONCLUSIONS AND CLINICAL IMPORTANCE: Hyperkalemia is a potential complication of CKD. In a subset of CKD dogs, hyperkalemia can be associated with commercial renal diets and could restrict use of these diets. Appropriately formulated, potassium-reduced, diets are an effective alternative to correct hyperkalemia.

Calcium and phosphorus homeostasis in dogs with spontaneous chronic kidney disease at different stages of severity.

BACKGROUND: Studies in dogs with experimental chronic kidney disease (CKD) have demonstrated that abnormalities of calcium-phosphorus (Ca-P) homeostasis occur frequently and have a negative effect on kidney function and survival. However, the prevalence of these alterations in dogs with naturally occurring CKD at different stages of severity has not yet been investigated. HYPOTHESIS: Abnormalities of Ca-P metabolism occur early in the course of CKD with an increased prevalence in more severe stages. ANIMALS: Fifty-four dogs with CKD and 22 healthy dogs. METHODS: Blood and urine samples were obtained for a CBC, biochemistry, determination of parathyroid hormone (PTH), calcitriol, and ionized calcium concentrations and urinalysis. Based on urine protein/creatinine ratio and serum creatinine concentration, dogs were grouped according to the IRIS classification for CKD. RESULTS: Hyperparathyroidism (HPTH) (PTH > or = 48 pg/mL) was diagnosed in 41 (75.9%) dogs with CKD. Its prevalence increased from 36.4% (stage 1) to 100% (stage 4). Hyperphosphatemia (P > 5.5 mg/dL) was present in 37 (68.5%) dogs; increasing in prevalence from 18% (stage 1) to 100% (stage 4). Receiver-operating characteristic curve analysis showed that serum phosphorus concentration in the 4.5-5.5 mg/dL range correctly identified the presence of HPTH in most dogs. Calcitriol concentration progressively decreased in dogs with CKD and differences became statistically significant by stage 3. CONCLUSION AND CLINICAL RELEVANCE: HPTH and hyperphosphatemia occur frequently in dogs with naturally occurring CKD, even at early stages of CKD in some dogs. These findings highlight the importance of monitoring these parameters early in the course of CKD.

Oxidative stress and neutrophil function in cats with chronic renal failure.

BACKGROUND: Oxidative stress is an important component in the progression of chronic renal failure (CRF) and neutrophil function may be impaired by oxidative stress. HYPOTHESIS: Cats with CRF have increased oxidative stress and decreased neutrophil function compared with control cats. ANIMALS: Twenty cats with previously diagnosed renal failure were compared with 10 age-matched control cats. METHODS: A biochemical profile, CBC, urinalysis, antioxidant capacity, superoxide dismutase (SOD) enzyme activity, reduced to oxidized glutathione ratio (GSH : GSSG), and neutrophil phagocytosis and oxidative burst were measured. Statistical comparisons (2-tailed t-test) were reported as mean +/- standard deviation. RESULTS: The CRF cats had significantly higher serum blood urea nitrogen, creatinine, and phosphorus concentrations than control cats, and significantly lower PCV and urine specific gravity than control cats. The GSH : GSSG ratio was significantly higher in the CRF group (177.6 +/- 197, 61.7 +/- 33; P < .02) whereas the antioxidant capacity was significantly less in the CRF group (0.56 +/- 0.21, 0.81 +/- 0.13 Trolox units; P < .005). SOD activity was the same in control and CRF cats. Neutrophil oxidative burst after Escherichia coli phagocytosis, measured as an increase in mean fluorescence intensity, was significantly higher in CRF cats than controls (732 +/- 253, 524 +/- 54; P < .05). CONCLUSIONS: The higher GSH : GSSG ratio and lower antioxidant capacity in CRF cats is consistent with activation of antioxidant defense mechanisms. It remains to be determined if supplementation with antioxidants such as SOD beyond the level of control cats would be of benefit in cats with CRF.

Measurement of urinary cauxin in geriatric cats with variable plasma creatinine concentrations and proteinuria and evaluation of urine cauxin-to-creatinine concentration ratio as a predictor of developing azotemia.

OBJECTIVE: To evaluate urine cauxin immunoreactivity in geriatric cats with variable plasma creatinine concentrations and proteinuria and to assess urinary cauxin-to-creatinine concentration ratio (UC/C) as a predictor of developing azotemia. ANIMALS: 188 client-owned geriatric (>or= 9 years of age) cats. PROCEDURES: A direct immunoassay was developed and validated for the quantification of urinary cauxin relative to a standard curve generated from a urine sample with high cauxin immunoreactivity. Relationships among UC/C, plasma creatinine concentration, and proteinuria were assessed. Nonazotemic cats were recruited and followed for 12 months. Urinary cauxin-to-creatinine concentration ratio was evaluated as a predictor of development of azotemia in these cats. RESULTS: No relationship was evident between UC/C and plasma creatinine concentration. A weak positive correlation was identified between UC/C and urine protein-to-creatinine concentration ratio (r = 0.212). At entry to the longitudinal study, those cats that later developed azotemia had a UC/C that was significantly higher than in those remaining nonazotemic after 12 months. CONCLUSIONS AND CLINICAL RELEVANCE: The UC/C did not vary with severity of azotemia but appeared contributory to the feline urinary proteome. High UC/C values were predictive of the geriatric cats in our study developing azotemia. However, it seems unlikely that UC/C will provide additional information about the measurement of urine protein-to-creatinine concentration ratio as a biomarker for the development of azotemia in cats.

Association between naturally occurring chronic kidney disease and feline immunodeficiency virus infection status in cats.

OBJECTIVE: To investigate the association between naturally occurring chronic kidney disease (CKD) and FIV infection status in cats in Australia. DESIGN: Case-control study. ANIMALS: 73 cats with CKD and 69 cats without historical, physical, or clinicopathologic evidence of CKD. PROCEDURES: Cats were tested for serum antibodies against FIV glycoprotein 40 (gp40) by use of an immunomigration assay. Information regarding age, breed (purebred or domestic), and sex was obtained from medical records. Analysis was performed on data from cats stratified into 2 age categories (< 11 years old and >or= 11 years old). Univariable and then multivariable analyses were performed to investigate the relationship between CKD and the study variable (FIV infection), the latter analysis accounting for breed (purebred or domestic), sex, and veterinary hospital of origin. RESULTS: Results of multivariable analysis revealed that younger cats with CKD (< 11 years old) were significantly more likely to have positive test results for serum antibodies against FIV gp40 than were cats without CKD. No significant associations were found between CKD and FIV infection, breed, sex, or hospital of origin among older (>or= 11 years old) cats in the multivariable analysis. CONCLUSIONS AND CLINICAL RELEVANCE: Among cats < 11 years of age, those with CKD were significantly more likely to have positive test results for serum antibodies against FIV gp40 than were cats without CKD. It cannot be definitively established from results of this study whether infection with FIV preceded the development of CKD, and the role, if any, of FIV in the establishment or progression of CKD remains to be determined.

Gene therapy by electroporation for the treatment of chronic renal failure in companion animals.

BACKGROUND: Growth hormone-releasing hormone (GHRH) plasmid-based therapy for the treatment of chronic renal failure and its complications was examined. Companion dogs (13.1+/-0.8 years, 29.4+/-5.01 kg) and cats (13.2+/-0.9 years, 8.5+/-0.37 kg) received a single 0.4 mg or 0.1 mg species-specific plasmid injection, respectively, intramuscularly followed by electroporation, and analyzed up to 75 days post-treatment; controls underwent electroporation without plasmid administration. RESULTS: Plasmid-treated animals showed an increase in body weight (dogs 22.5% and cats 3.2%) compared to control animals, and displayed improved quality of life parameters including significant increases in appetite, activity, mentation and exercise tolerance levels. Insulin-like growth factor I (IGF-I, the downstream effector of GHRH) levels were increased in the plasmid treated animals. Hematological parameters were also significantly improved. Protein metabolism changes were observed suggesting a shift from a catabolic to an anabolic state in the treated animals. Blood urea nitrogen and creatinine did not show any significant changes suggesting maintenance of kidney function whereas the control animal's renal function deteriorated. Treated animals survived longer than control animals with 70% of dogs and 80% of cats surviving until study day 75. Only 17% and 40% of the control dogs and cats, respectively, survived to day 75. CONCLUSION: Improved quality of life, survival and general well-being indicate that further investigation is warranted, and show the potential of a plasmid-based therapy by electroporation in preventing and managing complications of renal insufficiency.

Urinary cortisol/cortisone ratios in hypertensive and normotensive cats.

Hypertension is a common problem in older cats, particularly associated with chronic kidney disease (CKD). Reduced activity of 11beta-hydroxysteroid dehydrogenase type 2 predisposes to hypertension in human patients by allowing excessive stimulation of the mineralocorticoid receptor by cortisol. This study was designed to test the hypothesis that reduced conversion of cortisol to cortisone contributes to the development of systemic hypertension in some cats with CKD and idiopathic hypertension (iHT). The study included 60 client-owned cats: 21 clinically normal, 16 normotensive cats with CKD (NTCKD), 14 hypertensive cats with CKD (HTCKD) and nine iHTs. Urine cortisol and cortisone were extracted into dichloromethane and chloroform, respectively, prior to analysis by radioimmunoassay. Data are reported as median and range. The Kruskall-Wallis test was used to compare cortisol:cortisone ratios between groups with post-hoc testing using the Mann-Whitney U test. Wilcoxon signed-ranks test was used to compare results before and after treatment of hypertensive cats with amlodipine. The urinary cortisol:cortisone ratio was significantly higher in clinically normal cats (0.87; 0.46-1.39) when compared to NTCKD (0.60; 0.35-1.20; P<0.001), HTCKD (0.62; 0.34-1.00; P=0.002) and cats with iHT (0.65; 0.46-0.85; P=0.015). No statistical difference was detected between NTCKD, HTCKD and iHT groups. No effect of anti-hypertensive treatment on the urinary cortisol-cortisone ratio was detected (P=0.327). Reduced urinary cortisol to cortisone conversion does not appear to be associated with systemic hypertension in cats. In fact, the cortisol to cortisone shuttle appears to be more effective in cats with CKD (hypertensive and normotensive) and iHT than clinically normal cats. The mechanism for this potentially adaptive response to kidney disease is not clear.

Chronic kidney disease with three cases of oxalate-like nephrosis in Ragdoll cats.

Two unrelated Ragdoll cat mothers in Norway were found dead from renal disease. The histopathology was consistent with oxalate nephrosis with chronic or acute-on-chronic underlying kidney disease. Both cats had offspring and relatives with signs of urinary tract disease, including a kitten dead with urethral gravel. Eleven living Ragdoll cats, including nine relatives of the dead cats and the male father of a litter with similarly affected animals, were tested for primary hyperoxaluria (PH) type 1 and 2 by urine oxalate and liver enzyme analysis. Renal ultrasound revealed abnormalities in five living cats. One of these was azotaemic at the time of examination and developed terminal kidney disease 9 months later. A diagnosis of PH was excluded in 11 cats tested. The inheritance and aetiological background of the renal disease present in the breed remains unresolved at this point in time.

Evaluation of the measurement of serum cystatin C by an enzyme-linked immunosorbent assay for humans as a marker of the glomerular filtration rate in dogs.

The serum cystatin C (Cys-C) concentration is a better filtration marker than plasma creatinine (Cre) concentration in humans. In veterinary medicine, a few studies have shown that the serum Cys-C concentration in dogs is also a better marker than the plasma Cre concentration. The purpose of this study is to evaluate the applicability of measuring the serum Cys-C concentration by an enzyme-linked immunosorbent assay (ELISA) as a marker of the glomerular filtration rate in dogs with various renal dysfunctions. The serum Cys-C concentration in dogs with chronic kidney disease (CKD) was significantly higher (1.23 +/- 0.21 mg/L) than that in 76 control dogs (0.85 +/- 0.15) (P<0.001). The reference range of the serum Cys-C concentrations in samples from the 76 control dogs was 0.55-1.15 mg/l. Serum Cys-C concentration was more strongly correlated with plasma iohexol clearance (r=-0.704, P<0.001) than plasma Cre concentration in dogs (r=-0.598, P<0.001). In a receiver operating characteristics analysis, significant differences between the serum Cys-C and plasma Cre concentrations were found with regard to their AUC (0.949, [SE, 0.019] and 0.849 [SE, 0.029]) and diagnostic sensitivity (90.3% and 73.6%) for detecting decreased PCio (P<0.05). Therefore, the measurement of serum Cys-C concentration by ELISA is more useful for the detection of early CKD than measuring the plasma Cre concentration.

Serum phosphorus concentrations in dogs with leishmaniosis at different stages of chronic kidney disease.

Serum phosphorus concentrations were measured in 155 dogs with leishmaniosis at different stages of chronic kidney disease (CKD), and in 54 healthy dogs. CKD was classified into six stages, as follows: stage 0 (dogs with no evidence of CKD), serum creatinine (SCr) less than 125 micromol/l and urine protein:creatinine ratio (UPC) less than 0.2; stage 1A, SCr less than 125 micromol/l and UPC 0.2 to 0.5; stage 1B, SCr less than 125 micromol/l and UPC over 0.5; stage 2, SCr 125 micromol/l to 180 micromol/l; stage 3, SCr 181 micromol/l to 440 micromol/l; stage 4, SCr over 440 micromol/l. The dogs' serum phosphorus concentrations correlated significantly with the severity of CKD (P<0.001), and hyperphosphataemia (>1.8 mmol/l) affected 12 per cent, 11.8 per cent, 50 per cent, 76.9 per cent and 100 per cent of the dogs at stages 1A, 1B, 2, 3 and 4, respectively.

Hypophosphatemia in cats after renal transplantation.

OBJECTIVE: To report the prevalence of hypophosphatemia after renal transplantation in a historical cohort of cats. DESIGN: Case series. ANIMALS: Cats (n=86) that received a renal allograft. METHODS: Medical records (January 200-June 2006) were reviewed. Signalment, clinical signs, pre- and postoperative diet, pre- and postoperative clinicopathologic variables, renal histopathology, and outcome were retrieved. Prevalence, onset, duration, treatment and associated clinical signs of hypophosphatemia were recorded. A chi(2) test was used to compare hemolysis frequency between cats with normal serum phosphorus concentration or a single spurious low serum phosphorus concentration for <24 hours duration (group 1) and confirmed hypophosphatemia for >24 hours (group 2). A Cox proportional hazards model was used to evaluate the effects of hypophosphatemia on survival while controlling for other potentially confounding variables (age, sex, weight, body condition score, and pre- and 24 hours postoperative clinicopathologic variables). RESULTS: Eighty-six cats (mean age, 7.7 years) were identified. Hypophosphatemia occurred in 32 cats (37%), with a median onset of 2 days and median duration of 4 days. Treatment was initiated in 48 (56%) of hypophosphatemic cats. Survival and hemolysis frequency was not significantly different between groups, and no risk factors were identified. CONCLUSION: Hypophosphatemia occurs in cats after renal transplantation and does not affect survival. CLINICAL RELEVANCE: The clinical importance of hypophosphatemia in renal transplant recipients remains unknown.

Effects of T lymphocytes, interleukin-1, and interleukin-6 on renal fibrosis in canine end-stage renal disease.

Canine end-stage renal disease (ESRD) is defined as the almost complete failure of renal function or irreversible destruction and is characterized by extensive glomerular sclerosis, tubular atrophy, interstitial inflammation, and fibrosis. Renal fibrosis is a common pathway leading to kidney failure. Infiltrating immunocytes in the end-stage kidney and several related factors are involved in renal fibrogenesis. A total of 18 renal tissue samples were obtained from canine patients with ESRD using biopsy and necropsy procedures. The extent of renal fibrosis was histopathologically examined by Masson trichrome staining. T-cell and B-cell localization and macrophage lineages were determined by immunohistochemical staining. Additionally, interleukin-1 (IL-1), IL-2, and IL-6 levels in the canine ESRD kidney were immunohistochemically evaluated and compared with expression patterns in the normal kidney. Significant fibrosis and infiltrating immunocytes consistent with lymphocytes were observed. Although the B-cell count was increased in the end-stage kidney, immunostaining patterns disclosed a marked increase in the number of CD3(+) cells. Furthermore, the remarkable increase in IL-1 and IL-6 levels suggests that T cells in the kidneys of dogs with ESRD spontaneously express these cytokines. In this study, the correlation between the degree of renal fibrosis and cytokines in canine ESRD was examined. The present study shows that T lymphocytes and IL-6 play important roles in renal fibrosis.