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Medial degeneration as the primary lesion in coronary sclerosis in chickens
852
AMERICAN
MEDIAL
HEART JOURNAL
DEGENERATION AS THE PRIMARY LESION CORONARY SCLEROSIS IN CHICKENS* J. C. PATERSON, M.D., S. i. SLINGER, K. G. GARTLEY, B.S.A., ONTARIO,
From
the Department the Department
of Pathology, of Poultry,
M.S.A.,
IN
AND
CANADA
Uniuerersity of Western Ontario, Ontario Agricultural College
and
The observations reported were made in the course of a series of long-term studies on cholesterol arteriosclerosis of the coronary arteries of chickens. Routine examination of the coronary arteries of cholesterol-fed and control birds in the earlier stages of the experiments, has revealed: (1) a medial lesion which appears to be of prime importance in the genesisof coronary sclerosisin chickens ; (2) that the incidence of coronary sclerosis of the intimal variety is almost as great in the control birds (75 per cent) as in the cholesterol-fed birds (82 per cent) ; and (3) that cholesterol feeding markedly accelerates the coronary sclerosis in our experimental birds. These observations were made on the hearts of thirty-three White Leghorn cockerels, sacrificed from three and one-half to twelve months after the start of feeding with 2 per cent dry cholesterol, and on the hearts of thirty-three control birds of the same strain and age fed only the basal diet. The upper two-thirds of each heart was subjected to serial section at intervals of 400 microns. This provided approximately twenty-five equidistant sections, each containing three major coronary branches, from every specimen. The primary nature of the medial lesion was demonstrated by complete serial section of an early lesion in a coronary artery of a control bird. The observations in White Leghorn cockerels have been confirmed in Barred Rock cock birds in a second experiment. It is concluded that, under the conditions of the experiments, (1) cholesterol feeding accelerated but did not cause the coronary arteriosclerosis in our two strains of chickens; and (2) a medial degenerative focus was responsible for the initial proliferation of the intima of the coronary arteries in these birds. Experiments designed to elucidate the cause of the primary medial lesion in chickens are in progress. Discuss&z-A very unexpected feature of arteriosclerosis in cockerels was brought out by this paper: the primary medial change. This had not been observed by L. Katz and Horbick, who also used chickens as experimental objects. However, their birds were sacrificed when three to four weeks old, whereas Paterson’s birds were three and one-half months old at the time of his observations. Katz and Horlick commonly observed intimal changes within one and ,one-half weeks. Since it is true that dry cholesterol must be fed for a much longer period of time than if cholesterol in cottonseed oil is administered, the vehicle might modify the results of experiments. The latter method elevated blood cholesterol of chickens from 1,000 to 1,500 as against 400 to 500 mg. per 100 ml. after dry cholesterol feeding. In this connection, the importance of the additional diet, especially of butter fat, was pointed out by Davis. L. Katz brought out the fact that commercial cholesterol, at present, is of inferior quality, containing in some cases only 10 per cent of cholesterol. Paterson replied that he used Armour’s product which appears to be satisfactory. Conclusion.-There are obvious difficulties in comparing the results of seemingly analogous experiments. It appears doubtful that the chicken is a better experimental subject for the study of atheromatosis than the rabbit. *Paper in print, Arch. Path.
AMERICAN
MEDIAL
HEART JOURNAL
DEGENERATION AS THE PRIMARY LESION CORONARY SCLEROSIS IN CHICKENS* J. C. PATERSON, M.D., S. i. SLINGER, K. G. GARTLEY, B.S.A., ONTARIO,
From
the Department the Department
of Pathology, of Poultry,
M.S.A.,
IN
AND
CANADA
Uniuerersity of Western Ontario, Ontario Agricultural College
and
The observations reported were made in the course of a series of long-term studies on cholesterol arteriosclerosis of the coronary arteries of chickens. Routine examination of the coronary arteries of cholesterol-fed and control birds in the earlier stages of the experiments, has revealed: (1) a medial lesion which appears to be of prime importance in the genesisof coronary sclerosisin chickens ; (2) that the incidence of coronary sclerosis of the intimal variety is almost as great in the control birds (75 per cent) as in the cholesterol-fed birds (82 per cent) ; and (3) that cholesterol feeding markedly accelerates the coronary sclerosis in our experimental birds. These observations were made on the hearts of thirty-three White Leghorn cockerels, sacrificed from three and one-half to twelve months after the start of feeding with 2 per cent dry cholesterol, and on the hearts of thirty-three control birds of the same strain and age fed only the basal diet. The upper two-thirds of each heart was subjected to serial section at intervals of 400 microns. This provided approximately twenty-five equidistant sections, each containing three major coronary branches, from every specimen. The primary nature of the medial lesion was demonstrated by complete serial section of an early lesion in a coronary artery of a control bird. The observations in White Leghorn cockerels have been confirmed in Barred Rock cock birds in a second experiment. It is concluded that, under the conditions of the experiments, (1) cholesterol feeding accelerated but did not cause the coronary arteriosclerosis in our two strains of chickens; and (2) a medial degenerative focus was responsible for the initial proliferation of the intima of the coronary arteries in these birds. Experiments designed to elucidate the cause of the primary medial lesion in chickens are in progress. Discuss&z-A very unexpected feature of arteriosclerosis in cockerels was brought out by this paper: the primary medial change. This had not been observed by L. Katz and Horbick, who also used chickens as experimental objects. However, their birds were sacrificed when three to four weeks old, whereas Paterson’s birds were three and one-half months old at the time of his observations. Katz and Horlick commonly observed intimal changes within one and ,one-half weeks. Since it is true that dry cholesterol must be fed for a much longer period of time than if cholesterol in cottonseed oil is administered, the vehicle might modify the results of experiments. The latter method elevated blood cholesterol of chickens from 1,000 to 1,500 as against 400 to 500 mg. per 100 ml. after dry cholesterol feeding. In this connection, the importance of the additional diet, especially of butter fat, was pointed out by Davis. L. Katz brought out the fact that commercial cholesterol, at present, is of inferior quality, containing in some cases only 10 per cent of cholesterol. Paterson replied that he used Armour’s product which appears to be satisfactory. Conclusion.-There are obvious difficulties in comparing the results of seemingly analogous experiments. It appears doubtful that the chicken is a better experimental subject for the study of atheromatosis than the rabbit. *Paper in print, Arch. Path.