Plasma Lipids in Essential Hypertension.

Because of the frequent presence of cholesterol in the arterial lesions which develop during hypertension, the possibility was pointed out by Lemoine (1911) that hypercholesteremia might be a predisposing factor to atheromatosis. That it can be so in rabbits has been repeatedly demonstrated by administering cholesterol by mouth, with resultant production of hypercholesteremia and of atheromatous arterial lesions resembling those found in man (for literature see Wacker and Fahrig (1932) ). The application of these results to other animals is made doubtful, however, by the fact that it is impossible to produce atheromatous lesions by feeding cholesterol to dogs or cats (Anitschkow (1925); Yuasa (1928)). Most investigators have failed to find hypertension in rabbits with arterial lesions produced by cholesterol (see review by Dominguez (1927)). The first attempt to collect from human cases data bearing on the question appears to have been made by Lemoine (1911), who studied by a semiquantitative color test the cholesterol content of the serum in clinical hypertension, and found it abnormally high. Confirmatory results from cases of hypertension, only part of which were " essential," were reported by Pribram and Klein (1924) (47 cases, 76 per cent with high plasma cholesterol), Westphal (1924-5) (80 cases, 71 per cent high), and Gelman (1927) (37 cases, 68 per cent high. Wacker and Fahrig (1932) reported 12 cases of essential hypertension, with 18 control analyses of subjects with normal blood pressure. The normal cases averaged 152 mgm. of total cholesterol per 100 cc., with 180 as the maximum, while the cases of hypertension averaged 207 mgm., and all but 3 exceeded 180. On the other hand, Loewenstein (1928) reported 50 cases of hypertension, of which 4 were apparently nephritic and the rest essential; of the 50 he found only one with serum total cholesterol above 180 mgm. per 100 cc., which he considered the maximum normal value by the colorimetric method used. Weinstein and Weiss (1931) found high total cholesterol in only 5 of 37 cases of uncomplicated essential hypertension. Kirchgessner (1934) reported that most hypertensive subjects, in a series of 49, showed high values for free cholesterol, although total cholesterol was usually normal. Burger and Mobius (1934), in a paper appearing after our data were collected, found by the digitonin method entirely normal plasma concentrations of both free and total cholesterol in 20 cases of essential hypertension. Alvarez and Neuschloss (1931), like Loewenstein, found normal total cholesterol values (colorimetric) in hypertension cases. They studied also, however, the ability of the serum to dissolve additional free cholesterol, and found that the sera of 21 out of 25 hypertension cases were supersaturated with cholesterol. Medvei (1932) attempted to confirm these results with regard to saturation, however, and was entirely unable to do so; he found the serum approximately saturated with cholesterol in both normal subjects and patients with hypertension. Only 2 of Alvarez and Neuschloss' 25 cases, and perhaps 8 of Medvei's 30, appear to be essential hypertension. The available data show no agreement on the simple questions, (1) whether total cholesterol is high in the serum of patients with hypertension; and (2) whether the serum of such patients is supersaturated with free cholesterol. Only Kirchgessner's data, mostly colorimetric, bear on the question whether the ratio of free to esterified cholesterol is normal. Data on plasma lipids other than cholesterol in hypertension are scant and contradictory. Wacker and Fahrig (1932) in the paper already quoted, found that phosphatides, neutral fats, free cholesterol, and esterified cholesterol all showed a similar tendency to a moderate increase in hypertension. Hoesch (1931) on the other hand found lipid phosphorus normal in essential hypertension (7 cases). In view of the disagreement of results in the