VALUTAZIONE DEI PARAMETRI ERITROCITARI E RETICOLOCITARI NEL PAZIENTE FELINO NEFROPATICO IN RELAZIONE ALLA STADIAZIONE IRIS

Reticulocyte hemoglobin content (CHr) is considered a sensitive and specific measure of the iron status, with regard to erythrocytopoiesis in human patients affected by CKD. Several publications pointed out anaemia among the factors causing the progression of CKD by the vicious circle of the cardio-renal syndrome. The aim of this study was to evaluate the relationship between CHr and other haematological parameters, in cats affected by CKD staged according to the International Renal Interest Society. One hundred ninety one cats in stages II, III and IV were tested and twenty clinical healthy cats were enrolled as control group. CBC and reticulocyte indices were assessed using an ADVIA 120 Hematology System (Siemens Diagnostics Inc). Statistic analysis (one-way ANOVA and bivariate fit) was performed by JMP7 (SAS Inc). Anaemia was found in 33% of the cats in stage II, 51% in stage III, 74% in stage IV. The ANOVA showed a significant variance between CHr in the different stages of CKD (p=0,009). The linear regression showed that CHr and CHr/CHm ratio decrease with serum creatinine (SCr) increasing (p=0,03; p=0,01). MCVr, %Macro-r and %High-CHr showed an analogue significative trend too. CHr and CHr/CHm ratio tend to decrease with RBC, HCT and HGB decreasing (p<0,0001). Sideraemia wasn’t related with SCr, RBC, HCT and HGB. These findings may indicate that worsening nephropathy adversely affects the erytrocyte hemoglobin content, particularly those parameters that are used for the early assessment of iron deficiency anemia. Futhermore they may indicate that, with the progression of nephropathy, smaller reticulocytes with a lower content of hemoglobin are released (due to lower availability of iron). It was observed that CHr increases with increasing of reticulocyte count (p=0,02), reticulocyte percentage (p=0,03) and corrected reticulocyte percentage (p=0,002). These findings suggest that a greater regenerative response corresponds to major reserves of iron for eritropoiesis. As CHr and the CHr/CHm ratio decrese, a significant increase of leukocytes was shown by linear regression. A significant increase of neutrophils, decrease of lymphocytes and eosinophils were also observed. Although these results are consistent with a stress leucogram which is well known in patients affected with CKD, in human it is referred that low CHr could be associated with inflammatory process (that could contribute to the progression of nephropathy) and erythropoietin resistance, but not necessarily with iron-deficiency. These findings suggest that CHr trend has to be carefully examined also in feline patients affected by CKD.