Studies on the Histogenesis of Experimental Endocarditis

Abstract

Endocarditis was experimentally produced in rabbits by streptococcus sanguis, rabbits brain phosphatide and their combination in order to study several factors for development of the disease and the histogenesis with reference to the time interval between the injection and the onset of endocarditis.
Results were as follows:
1) Only a mild damage of endocardium was caused by the every other day injection of either phosphatide or bacteria alone, representing a mild valvulitis characterized by edema, localized swelling of endocardial cells and swelling of fibrocytes. A real bacterial endocarditis could be only produced by the combined use of the two (every other day injection).
2) Follow-up studies on the histologenesis of experimental bacterial endocarditis revealed that even a single injection of either str. sanguis or phosphatide produced various histologically different changes.
These were:
a) Thrombus attached on the desquamated endocardium which gradually increased in size resulting in the cellular infiltration in it.
b) Proliferation of histiocytic cells in the subendothelial layer.
c) Serous inflammation of the subendothelial layer (Eöhmig).
Any one of the above mentioned changes may lead to the bacterial endocarditis.
3) Bacterial colonies in the endocardial foci, especially in the fibrin thrombus or in the fibrinoid substance could not be found until the stage of advanced leucocytic infiltration in the thrombus, histiocytic infiltration in subendothelial layer and appearance of the fibrinoid substance in it.
4) When these changes, cellular infiltration and histiocytic reaction further advanced, then the lamina elastica became loose, torn and destroyed resulting in ulcer formation.