Effects of Circulating Red Cell Mass on Diet-Induced Atrial Thrombosis in Mice

Atrial thrombosis is a common lesion in female Taconic Swiss mice fed a high-fat (28%), low-protein (8%), hypolipotropic diet for 10 wk or longer. After the third week of such feeding the mice studied here were injected with either erythropoietin, washed, packed red blood cells, lysed red blood cells, plasma or physiological saline. In mice receiving injections of lysed red cells, plasma or saline, respectively 75, 54 and 82% of those surviving for 10 wk had developed atrial thrombosis. Hematocrits were 9.3% or below in these groups. Hematocrits were maintained at an average of 33.0% in the erythropoietin group and 32.4% in the transfused (packed erythrocytes) group. Only one of the erythropoietin injected animals and none of the transfused animals developed atrial thrombosis. The evidence indicates that the anemia induced by the experimental diet results from lack of erythropoietin production or activity and that the hypoxia of anemia plays a role in the development of atrial thrombosis.