One of the most important medical problems from all points of view— pathogenic, therapeutic and even social—since it still represents the chief direct cause of death in most civilized societies, is that of arteriosclerosis. The fact that lipids seem to intervene in its pathogenesis, has led us to consider this condition from the point of view of biological offbalances. With the development of our research, we tried to apply to this condition a systematic analysis in accordance with the basic concepts presented above. This attempt has permitted us to arrive at some new views which will be discussed briefly here.

The analysis of the specific manifestations of arteriosclerosis from the point of view of organization, that is, as related to the different levels, led us to recognize that it represents a condition principally limited to the level organism, and more especially to its secondary part, the circulatory system. Many of the fundamental characters of the condition could be explained by the relationship of this level to other levels of the organization, as we will see below.

From the point of view of the dualistic concept, it was easy to see that arteriosclerosis corresponds to an offbalance type A. All the analyses concerning the systemic level show patterns which indicate this offbalance. High urinary surface tension, low urinary specific gravity, high urinary pH, low urinary sulfhydryl index, found in the routine analyses point to such an offbalance. The long persistence of the skin wheal seen in the subjects analyzed, confirms this diagnosis. The fact that some manifestations of arteriosclerosis can be induced experimentally in animals through the administration of cholesterol, has placed into limelight the pathogenic role of cholesterol. While its administration in high amounts to rabbits or cockerels induces atheromas, it does not induce the complex condition itself. Usually the animals return to normal, even with a rapid healing of their atheromas after the suppression of the administration of cholesterol. Although hypercholesteremia represents thus only one pathogenic factor, it appeared interesting to investigate its intervention in the condition.

The relationship of cholesteremia to arteriosclerosis is certainly not a simple one. The total amount of cholesterol in blood alone, in its free form, and the macromolecules of certain dimensions resulting from their bond to the other constituents of the blood, although related to arteriosclerosis, do not seem to represent by themselves the pathogenic factor of this condition. This latter seems to be related to a more specific intervention of this substance at the level of the blood and circulatory system. Research in this field has led us to recognize this special intervention.

It is a known fact that the appearance of crystals of cholesterol in the cells of the intima of the arteries and in the cells of the vasa vasorum represents an essential factor in the pathogenesis of atheromas. Study of the capacity of blood serum to dissolve or, on the contrary, to precipitate cholesterol has permitted to link it with the appearance of specific arterial lesions in this condition.

In this study, we used the procedure originally devised by Policard when he investigated the relationship of cholesterol and arthritis. Blood is obtained through veinous puncture and the serum is separated aseptically. The amount of total cholesterol is determined in the blood serum. A sterile crystal of cholesterol is added to the serum. The treated serum is incubated for 6-12 hours at 37°C. The serum is then separated through filtration from the crystal added, or from those formed during the incubation. The difference between the amount of cholesterol in the serum before and after incubation with the crystal, shows that while some sera increase their content in cholesterol through this treatment, others decrease it.

We could show that the serum of those rabbits which were fed with two grams of cholesterol daily and which have a tendency to make atheromas, precipitates cholesterol. Oppositely, the resorption of atheromas seen in rabbits after the suppression of the feeding with cholesterol, was seen to occur together with the blood serum capacity to dissolve cholesterol. The relationship between this capacity to precipitate cholesterol and the appearance of atheromas was confirmed by the fact that it could not be seen in rats fed with cholesterol, where atheromas appear very seldom. Further it was seen present in subjects prone to make vascular occlusions. The administration of high amounts of cholesterol to animals with tumors has led to the appearance of vascular occlusions followed by ischemic infarcts in the tumors. The occlusion could be related to the proliferation of the arterial endothelium and the capacity to precipitate cholesterol.

The incubation of citrated blood at 37°The incubation of citrated blood at 37°

Fig. 152. The incubation of citrated blood at 37° C changes only little the amount of cholesterol in Case (a), while it determines a rapid decrease in Case (b).

In a further study of the cholesterol in blood, we investigated the capacity of the different samples of blood to cause their cholesterol to disappear after incubation at 37°C. We could show that while some samples of citrated blood kept at 37°C under sterile conditions, decrease their cholesterol content rapidly, others do not change it even after days of incubation. Figure 152 shows two such examples. We could also show that in rabbits fed with cholesterol and having atheromas, their blood lacked the capacity to make cholesterol disappear after incubation, differing from what was observed in the majority of the controls.

We then studied in another group of researches, the relationship between red cells and their cholesterol content. We could show that by washing red cells with saline, they lose their cholesterol. By using saline in amounts corresponding to the plasma, this effect could be measured. However, while in some bloods a manifest loss in cholesterol occurs with the first or second washing, in others the loss occurs very slowly. Sometimes ten such washings are necessary before the cholesterol is low enough to start hemolysis. Figure 153 illustrates two such examples. We could show that the red cells of rabbits fed with cholesterol demonstrated a higher capacity to retain cholesterol throughout saline washings, than did red cells of normal animals.

The analysis of arteriosclerotic cases from the point of view of this relationship between blood and cholesterol has shown that the tendency to precipitate cholesterol, coupled with a low capacity to make it disappear through incubation, is encountered in those cases prone to acute episodes of vascular occlusion.

The washing of human red cells with saline

Fig. 153. The washing of human red cells with saline induces a very slow decrease in their content in cholesterol in Case (c). The hemolysis starts in this case at the 10th washing. In Case (d), such an effect appears after the second washing.

The big differences seen in the behavior of blood towards cholesterol has raised the problem of its relationship from an organizational point of view. The application of the concept of a proper level in the organization to cholesterol has permitted us to interpret the occurring changes.

Cholesterol represents a cellular constant and the classical studies of Shaffer have shown the importance of its amount in the cells. The quantity of water retained by the cells is largely determined by the ratio between cholesterol and fatty acids of the cells. Under this aspect, we have hypothetically considered hypercholesteremia as corresponding to a kind of defense response of the blood level toward the changes occurring at the level below it, respectively toward an opposite lipidic offbalance occurring at cells, tissues or even organs. We investigated hypercholesteremia under this specific aspect. We have seen above that in the lipidic system, sterols correspond to an anti fatty acid agent. This led to the supposition that hypercholesteremia could represent a response at the blood level to changes taking place at a lower level in the relationship between fatty acids and cholesterol. A first fundamental finding in this direction was the fact that the amount of cholesterol in the blood represents—as shown for potassium, copper, hydrogen ion concentration, etc.—values which, while maintained constant by a regulatory system, vary very widely under different circumstances. These wide variations would correspond rather to a secondary response. The amount of blood cholesterol would change as a secondary constant. A balanced system of manufacturing and excreting insures the maintenance of this secondary blood cholesterol amount. In the case of cholesterol, the manufacturing factor seems to be represented by the R E S cells, while the excreting factor by the liver, primarily by the Kuppfer cells and secondarily by the hepatic cells, the cholesterol being ultimately excreted in the bile. We do not know the factor which directly changes the manufacturing or excretion of cholesterol in blood and which consequently maintains its balance. By analogy we consider the changes in blood cholesterol value to result from those occurring at the lower levels as seen for other substances such as potassium, or copper, for which blood does not represent the proper level. According to this view, with cholesterol having the cellular level as its proper level and the blood as superior level, the blood changes would reflect secondary responses to those occurring at lower levels. We saw such changes at the cellular level in old age.