Two cases with transient lipoprotein lipase (LPL) activity impairment: evidence for the possible involvement of an LPL inhibitor.

UNLABELLED: Two independent severe hypertriglyceridemic infants with transiently impaired lipoprotein lipase (LPL) activity were observed and the causes were explored. Both infants were female, born prematurely with low birth weight and developed hypertriglyceridemia (Fredrickson type V hyperlipidemia: high VLDL and low LDL/HDL) a few months after birth. While mass levels of their post-heparin plasma LPL and apoprotein C-II (apo C-II), a physiological activator of LPL, were normal, their post-heparin plasma LPL activities were remarkably impaired. Both of their mothers' post-heparin plasma LPL activities were slightly or moderately impaired as well, without a decrease in the LPL mass level. No mutations in the genes for LPL and apo C-II were detected in either patient. In an in vitro study with their serum at onset, we could not detect any distinct circulating inhibitors for LPL. There was no data supporting infection or autoimmune diseases, which might have an impact on LPL activity, during the follow-up period. Levels of their plasma triglyceride (TG) and total cholesterol (TC) were decreased quickly by a dietary intervention with medium-chain triglyceride (MCT) milk and kept normal even after stopping the intervention at around age 1 year. However, their low post-heparin LPL activity persisted and returned to normal at around age 2 years. Their low HDL cholesterol levels persisted even after recovery of the TG and TC levels, although lecithin:cholesterol acyltransferase (LCAT) and cholesterol-ester-transfer protein (CETP), two key enzymes of HDL metabolism, were normal throughout the course. The exact reasons why their post-heparin LPL activities were impaired for a certain period and why their HDL cholesterol levels have remained low are still unclear. CONCLUSION: Transiently impaired LPL activity with no defect in LPL enzyme induced severe hypertriglyceridemia in infants. The transient occurrence of inhibitor(s) for LPL was proposed.

Xantomas: marcadores cutáneos de hiperlipidemias / Xanthomas: Cutaneous markers of hyperlipidemias

Se presenta una revisión sobre los xantomas cutáneos enfatizando su importancia como marcadores de padecimientos sistémicos principalmente de la hiperlipoproteinemias primarias y secundarias. Existe una estrecha relación entre el trastorno metabólico y tipo de lípido sérico elevado con las diferentes variedades de xantomas. Se destaca la necesidad del diagnóstico temprano de la dislipidemias por el riesgo de la enfermedad coronaria aterosclerosa en pacientes jóvenes

Tuberoeruptive xanthomas: unusual presentation of type V hyperlipoproteinemia.

We report a case of pedal tuberoeruptive xanthomatosis associated with ethanol-induced type Vhyperlipoproteinemia that was controlled with diet, withdrawal from ethanol use, and the fibric acid derivative gemfibrozil.

[Physiopathology of primary hyperlipidemias]. / Physiopathologie des hyperlipidémies primitives.

The authors review the present status of our knowledge of the physiopathology of primary hyperlipidaemia. The mechanisms of familial hypercholesterolaemia (reduction in the number of LDL receptors on the surface of hepatic and extrahepatic cells) and of type III hyperlipidaemia (an apo E abnormality associated with another metabolic disorder) are relatively well known. However, the physiopathology of the other hyperlipidaemias remains obscure: polygenic hypercholesterolaemia probably due to a disorder of hepatic LDL receptors; combined familial hyperlipidaemia probably due to abnormally high hepatic apo B synthesis; hyperlipidaemia related to defective chylomicron catabolism in which the lipase system plays a central role and hypertriglyceridaemia caused by an association of genetic and environmental factors.

Influence on serum lipids, lipoproteins and blood pressure of mackerel and herring diet in patients with type IV and V hyperlipoproteinemia.

Eight patients with type IV and V hyperlipoproteinemia were put on a mackerel and herring diet of an isocaloric regimen for 2 weeks, in a cross-over design. At the end of the dietary periods a predominant increase of eicosapentaenoic acid (EPA - C20:5, n-3) in cholesterol esters and of docosahexaenoic acid (DHA - C22:6, n-3) in serum triglycerides, being more pronounced after mackerel as compared to herring diet, could be confirmed. After mackerel diet serum triglycerides and total cholesterol were significantly lower, returning to basal levels 3 months later. High density lipoprotein (HDL) cholesterol appeared slightly increased after mackerel diet and decreased to initial values thereafter. After herring diet, which contained half as much EPA as compared to mackerel diet, the differences were minor. The decline of free fatty acids (FFA) and insulin at the end of the mackerel period reached the level of significance 60 min and 120 min, respectively, after glucose load. A significantly lower systolic blood pressure in recumbent and upright position after the mackerel period could be found, whereas diastolic pressure and blood pressure after herring diet remained unchanged.

[Primary hyperlipoproteinemias. Clinical, biological and physiopathological aspects]. / Les hyperlipoprotéinémies primaires. Aspects cliniques, biologiques et physiopathologiques.

Primary hyperlipoproteinemias are of great interest as for the physician, as for the searcher, because of their atherogenic properties; on the other hand, a new type of hyperlipoprotenemia, namely hyperalphalipoproteinemia, seems to be a protective factor against clinical complications of atherosclerosis. The clinical, biological and pathophysiologic aspects of these diseases are studied both from author's experience and from the literature data.