METABOLIC FINDINGS IN THE ERYTHROCYTES OF CARDIOPATHIC AND ANEMIC DOGS

Few data are available on the activities of canine erythrocyte enzymes and on 2,3 diphosphoglycerate (2,3DPG) concentrations in pathological conditions other than heritable erythrocyte defects. Because some dis eases might affect erythrocyte metabolism and oxygen transport, we eva luated these parameters in 10 healthy dogs and in dogs with symptomles s dirofilariosis (n=9), mild (n = 13) and severe (n = 8) cardiac failu re, and haemolytic anaemia (n = 8). To evaluate possible membrane dama ge, the osmotic fragility of the red cells was measured. No haematolog ical abnormalities were found in tile dogs with mild cardiopathy or in those with symptomless dirofilariosis. Severe anaemia and neutrophili c leucocytosis were found in the dogs with haemolytic anaemia and, to a lesser degree, in those with severe heart failure. In dogs with thes e two diseases, elevated values obtained were, respectively: pyruvate kinase (PK) 17.5 +/- 10.3 U/g haemoglobin (Hb) (P<0.001) and 11.6 +/- 7.5 U/g Hb (P<0.01); glucose-6-phosphate dehydrogenase (G6PDH) 8.9+/-5 .4 U/g Hb (P<0.001) and 5.6 +/- 4.2 U/g Hb; 2,3DPG 21.8 +/- 4.9 U/g Hb (P<0.001) and 22.5 +/- 4.1 U/g Hb (P<0.001). The increased 2,3DPG con centrations may have been due to diminished oxygen availability but th e observed enzymatic changes were attributed mainly to the presence of young red blood cells: there was a positive correlation between nucle ated red blood cells and PK activity, G6PDH activity and 2,3DPG concen tration and a negative correlation between mature erythrocytes and PK activity, G6PDH activity and 2,3DPG concentration. This was supported by the derivative curve of the fragiligram, which showed two or three peaks corresponding to different erythrocyte populations and by the ne gative correlation between the maximum haemolytic NaCl concentration a nd the reticulocyte number. The measurement of PK and G6PDH activity a nd of the 2,3PG concentration, together with information provided by t he fragiligram, would seem to be of value in defining the clinico-haem atological picture in clinical heart diseases and haemolytic anaemia. (C) 1998 W.B. Saunders Company Limited.