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Tesi etd-05022011-173341


Thesis type
Tesi di dottorato di ricerca
Author
LIPPI, ILARIA
URN
etd-05022011-173341
Title
EARLY DIAGNOSTIC AND PROGNOSTIC MARKERS OF CHRONIC KIDNEY DISEASE (CKD) IN CANINE AND FELINE PATIENTS
Settore scientifico disciplinare
VET/08
Corso di studi
MEDICINA VETERINARIA
Commissione
tutor Prof.ssa Guidi, Grazia
Parole chiave
  • GFR
  • dog
  • cTnI
  • CRP
  • CKD
  • cat
  • Ca x P product
  • alpha-tochopherol
  • ionized calcium
Data inizio appello
09/06/2011;
Consultabilità
completa
Riassunto analitico
SUMMARY<br><br>Chronic kidney disease (CKD) is a clinical syndrome with a high prevalence both in human and veterinary medicine. Being able to formulate an early diagnosis of CKD can allow veterinarians to introduce a dietary and medical therapy, which can dramatically reduce progression towards end stage renal disease (ESRD)1. At the same time, strong evidences of a deep relationship between heart and kidney in the progression of CKD in humans, have led to a greater attention towards potential markers of prognosis and negative outcome of the disease, even in small animal population. The present research project has been organized in two sections2,3. <br><br>FIRST SECTION<br>The aim of the first part of the study has been to validate a glomerular filtration rate (GFR) method, at a low number of plasma samples, through the plasma clearance of iohexol in both CKD and clinically healthy cats. <br>MATERIALS AND METHODS - After the owners’ informed consent, 53 clinically healthy and 14 CKD cats have been submitted to a first blood sample (0) and to an eight-hour clearance study. Iohexol (Omipaque® 300 mgI/ml) has been intravenous injected at the dose of 64.7 mg/kg body weight. Heparinised blood samples have been taken at 5 and 30 minutes and 1, 2, 4, 6 and 8 hours from the completion of iohexol injection. Plasma has been obtained and each sample has been stored at -20 C° till extraction process and HPLC analysis. Pharmacokinetic analysis has been performed through the software Easy Fit® for Macintosh (Istituto Mario Negri, Milano, Italia) and, for each subject of HC and CKD group, plasma concentration of iohexol/time curves have been analyzed through a non-compartimental kinetic model. Then, a pharmacokinetic analysis has been carried on after the application of simplified models (Model A, Model B, Model C and Model D) with a lower number of blood samples. Statistical analysis has been performed by using the software GraphPad Prism 4 for Macintosh, USA.<br>RESULTS – t-test analysis (p&lt;0.05) between GFR of CH and CKD patients has shown a significant difference between the two groups of subjects, not only for reference method (p=0.003), but also for Model A (p=0.0005), Model B (p=0.01), Model C (p=0.001) and Model D (p=0.004). Pearson correlation analysis (p&lt;0.05) between each simplified model and reference method has shown a positive linear correlation with vey high values of Pearson r and R2. <br>CONCLUSIONS - The present study has validated a safe, simple and accurate three-sample HPLC method (5’ – 30’ – 1 hour) for the determination of GFR through the plasma clearance of iohexol in feline patients. This model represents an attractive and cheap alternative to cumbersome plasma clearance methods, with a dramatic applicatory potential in different clinical settings.<br><br>SECOND SECTION<br>The aim of the second part of the study has been to assess serum ionized calcium, total calcium, calcium corrected for albumin (cCaAlb), calcium corrected for total proteins (cCaPt), Ca x P product (Ca x P), cardiac troponin I (cTnI), C-reactive proteine (CRP) and α-tochopherol in CH and CKD canine patients at different stages of the disease. <br>MATERIALS AND METHODS – serum ionized calcium, total calcium, cCaAlb and cCaPt have been determined in 301 CKD and 125 CH patients, while Ca x P, cTnI, CRP and α-tochopherol have been assessed in 13 IRIS 1, 7 IRIS 2, 13 IRIS 3 and 11 IRIS 4 subjects. Ionized calcium has been determined through a selective ion method (STAT PROFILE® pHOx Plus, GEPA, Milano, Italy), cTnI through an immunometric method (IMMUNOLITE 2000® Immunoassay System), CRP through an immunometric method (RANDOX immunoturbidimetric kit for CRP, Vet Med Lab, IDEXX, Germany) and α-tochopherol through HPLC (Chromosystems-Diagnostic Kit HPLC &amp; LC/MS, Munchen, Germany). Statistical analysis has been performed by using the software GraphPad Prism 4 for Macintosh, USA.<br>RESULTS – One-way ANOVA has reported a significant difference (p&lt;0.0001) in ionized calcium concentration among CH, IRIS 1, IRIS 2, IRIS 3 and IRIS 4 and χ2 analysis has shown a significant difference (p&lt;0.0001) in the number of patients with hyper, hypo and normocalcemia according to the progression of the disease. One-way ANOVA among CH subjects and IRIS 1, IRIS 2, IRIS 3 and IRIS 4 patients has reported a significant difference in the mean value of Ca x P (p&lt;0.0001). No significant correlation has been found between Ca x P and plasma creatinine in any of IRIS classes. The number of patients with Ca x P above 70 mg/dl has been reported to increase significantly (p&lt;0.0001) with the severity of CKD, as well as the number of dead patients (p&lt;0.0008). Finally, Kaplan-Meier survival curve has shown a significantly higher percentage of survival (p&lt;0.0002) of CKD patients with Ca x P below 70, compared to patients with Ca x P above 70. One-way ANOVA among CH subjects and IRIS 1, IRIS 2, IRIS 3 and IRIS 4 patients has reported a significant difference in the mean value of cTnI (p&lt;0.02). No significant correlation has been found between cTnI and plasma creatinine in any of IRIS classes. The number of patients with cTnI above 0.20 ng/ml has been reported to increase significantly (p&lt;0.0001) with the severity of CKD, as well as the number of dead patients (p&lt;0.02). Finally, Kaplan-Meier survival curve has shown a significantly higher percentage of survival (p&lt;0.0002) of CKD patients with cTnI below 0.20 ng/ml, compared to patients with cTnI above 0.20 ng/ml. One-way ANOVA among CH subjects and IRIS 1, IRIS 2, IRIS 3 and IRIS 4 patients has reported a significant difference in the mean value of CRP (p&lt;0.0001). No significant correlation has been found between CRP and plasma creatinine in any of IRIS classes. The number of patients with CRP above 9.7 mg/l has been reported to increase significantly (p&lt;0.0001) with the severity of CKD, as well as the number of dead patients (p&lt;0.0009). Finally, Kaplan-Meier survival curve has shown a significantly higher percentage of survival (p&lt;0.001) of CKD patients with CRP below 9.7 mg/l, compared to patients with CRP above 9.7 mg/l. One-way ANOVA among CH subjects and IRIS 1, IRIS 2, IRIS 3 and IRIS 4 patients has reported a significant difference in the mean value of α-tochopherol (p&lt;0.0002). A significant correlation (p=0.00) has been found between α-tochopherol and plasma creatinine in IRIS 2. The number of patients with α-tochopherol below 21.6 ppm has been reported to increase significantly (p&lt;0.0001) with the severity of CKD. No significant difference in the number of survived and dead patients has been found between subjects with α-tochopherol below and above 21.6 ppm. Finally, Kaplan-Meier survival curve has shown no significant difference. <br>CONCLUSIONS – The present study has demonstrated a significant increase in Ca x P, cTnI and CRP serum concentration according to the progression of CKD. Ca x P, cTnI and CRP have shown a prognostic, not IRIS stage-dependent, value and a significant correlation towards mortality. In CKD dogs, as well as in humans, alterations of calcium-phosphate metabolism, cardiovascular injury and inflammation seemed to play a significant role in the progression and negative outcome of CKD. No correlation has been reported between mortality and α-tochopherol, although a significant serum reduction with the progression of CKD has been shown.<br>
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