Endogenous Hyperglyceridemias

When one departs from hyperchylomicronemia, the classification of EHL becomes much less simple. Since pure hyper chylomicronemia is a quite rare entity and since EHL is by no means rare, it is obvious that appropriate measuring sticks are necessary. Despite points of difference, it appears possible to concentrate upon certain features which most endogenous hyperlipemics have in common and come up with some clarification of the subject. 

The term endogenous hyperglyceridemia as used here is not meant to imply that alimentary fat cannot contribute to the hypertriglyceridemia in such cases under appropriate conditions. However, it seems likely that a basic defect in all the S3mdromes to be discussed is associated with some type of abnormality of metabolism of endogenous very low density lipoprotein with regard either to formation (Farquhar et al. 1963) and/or clearing of these particles. Other mechanisms, secondary to this defect, seem to come into play particularly with more severe forms of the syndrome. 

In spite of evidence suggesting some basic common denominator in most endogenous hyperglyceridemics, it seems reasonable at the present time to divide subjects with these syndromes into three major groups so as to not obscure existing differences and to stimulate further analysis and evaluation. 

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A classification of EHL, as proposed by Thannhatjser (1950), into juvenile and adult forms — the latter frequently exhibiting mild glycosuria in addition to hyperglyceridemia — cannot be maintained in this strict sense. However, it still aids in consideration of differential diagnosis of EHL, since the endogenous hyperglyceridemias, to be described, are commonly diagnosed in adults. 

Fig. 3. Pure carbohydrate-induced byperglyce-ridemia (endogenous hyperglyceridemia group 1). Significant hyperglyceridemia was observed in this 47 year old male subject on a high carbohydrate, fat-free diet. Substitution of most of the carbohydrate by fat resulted in progressive fall in plasma glycerides to normal...

Fig. 7. Paper electrophoresis with albumin-containing buffer of a normal plasma (1) and plasma of a subject with endogenous hyper-glyceridemia (2). Lipid stain with oil red O. A clearly separated pre-j8-band is present in endogenous hyperglyceridemia. The -lipo-protein band is stained faintly in the normal control, but hardly visible in the hyperlipemic subject...

Glycerol is present at low concentration in serum occasionally, patients have hyperglyceridemia. Endogenous glycerol must be consumed before triacylgly-cerol lipase (EC 3.1.1.3) is measured to avoid falsely increased lipase values. 

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