Childhood-onset chylomicronaemia with reduced plasma lipoprotein lipase activity and mass: identification of a novel GPIHBP1 mutation

OBJECTIVES

Deficiency in the catabolism of triglyceride-rich lipoproteins is the main cause of childhood-onset chylomicronaemia syndrome. Missense mutations in lipoprotein lipase (LPL) or in proteins influencing LPL activity or stability have been shown to be critical determinants of chylomicronaemia syndrome. The main objective of this study was to assess the primary deficiency in five cases of childhood-onset chylomicronaemia syndrome.

SETTING

Lipid clinic at a university hospital,

SUBJECTS

Subjects presenting with severe hypertriglyceridaemia and chylomicronaemia syndrome in which reduced LPL activity and mass were observed.

INTERVENTIONS

Analysis of LPL and GPIHBP1 genes.

RESULTS

Amongst the five patients, one novel homozygous missense mutation (p.C68Y) in exon 3 of GPIHBP1 was identified. The other four patients were homozygous for the common LPL mutation p.G188E.

CONCLUSION

These findings provide further evidence that GPIHBP1 is involved in the catabolism of triglyceride-rich lipoproteins and plays a role in childhood-onset chylomicronaemia.

Increment of the platelet count in temporal arteritis: response to therapy and ischemic complications

Temporal arteritis (TA) is a vasculitis involving mainly cranial branches of the aorta that can lead to ischemic complications such as amaurosis or ischemic stroke. Increment in the platelet count has been described in the acute period of the disease. We studied retrospectively the platelet count in patients with TA, its association with ischemic complications and quantified its response to therapy. We found thrombocytosis in 44% of 34 patients with TA, with a mean reduction in the platelet count of 25.1% after therapy. We were also able to quantify the increment in the platelet count at the onset of the disease and its response to prednisone in a group of 5 patients. We did not find any relation between platelet count and ischemic complications of the disease or the result of the temporal artery biopsy. In conclusion TA is associated with an increase in the platelet count, with a 25% reduction after prednisone therapy. These two determinations are not related to ischemic complications of the disease.

Asthma self-management education program by home monitoring of peak expiratory flow

A prospective controlled trial of home monitoring of peak expiratory flow rate (PEFR) was conducted to determine the usefulness of an objective measure of lung function in association with an education program and a medication self-management plan in reducing morbidity in adult patients with asthma. Thirty-five patients managed themselves, using peak flow readings as the basis for the therapeutic plan coupled with educational intervention, whereas 35 control patients used symptoms and spirometric data for following physicians' treatment plans. After a 6-mo study period, patients in the experimental group showed statistically significant improvements in morbidity parameters (days lost from work, acute asthma attacks, days on antibiotic therapy, physician consultations, and emergency room admissions for asthma), increases in FVC, FEV1, and FEV1/FVC, mean PEFR and mean morning PEFR, decrease in percentage of the mean PEFR amplitude, and a reduction in the use of inhaled beta-agonists, oral theophylline, and oral prednisone. Although improvements in some of these parameters were also found in the control group, they did not reach the levels of significance obtained in the experimental group. The personal use of an objective measure of lung function in association with a medication self-management plan leads to improvement in the patient's condition.

Short-term effect of various doses of cyclosporin A on plasma lipoproteins and its distribution in blood: an experimental study

Hyperlipidaemia commonly develops in both transplant recipients and experimental animals receiving cyclosporin A (CsA). However, the threshold of CsA induced-changes on lipoproteins and the role of parenteral vehicle (cremophor) has not been defined. Male Wistar rats were classified into five groups of six animals each and received CsA in cremophor vehicle at doses of 5, 10 or 20 mg kg-1 d-1, s.c., vehicle alone or saline for 7 d. Blood was obtained 24 h after the last dose and plasma was analysed. Plasma very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein subfractions (HDL-2, HDL-3) were isolated by sequential ultracentrifugation and their content of cholesterol, triglyceride and phospholipid was determined. Whole blood and trough plasma CsA levels were measured by monoclonal radioimmunoassay. Plasma lipids did not differ significantly among the five groups. At a dose of 20 mg kg-1 d-1 of CsA VLDL cholesterol rose significantly (P < 0.05). Administration of either CsA or cremophor vehicle increased HDL-2 phospholipids (P < 0.05) and decreased HDL-3 cholesterol. There was not a linear relationship between whole blood and plasma CsA levels and increasing CsA doses. Short-term treatment with low doses of CsA have little influence on lipid profile in the rat. Changes on lipoprotein composition can be attributed mainly to cremophor vehicle, conceivably due to its ethanol content.

Apolipoprotein distribution in plasma HDL subfractions in alcohol consumers

Alcohol intake is known to increase plasma HDL subfractions and apo A levels. Few data are available, however, with regard to precise apoprotein composition of plasma lipoproteins in alcohol consumers. The aim of the present study was to examine the lipid and apoprotein distribution in plasma lipoproteins of subjects with different levels of alcohol intake. Thirty-six male regular drinkers were classified as social (n = 10, average daily consumption greater than or equal to 5 and less than or equal to 20 g), moderate (n = 11, average daily consumption greater than 20 g and less than 70 g) and heavy drinkers (n = 15, average daily consumption greater than or equal to 70 g). Reference data were obtained from 11 subjects, all lifelong abstainers. Lipoproteins were fractioned by sequential ultracentrifugation and apolipoprotein distribution in VLDL, HDL-2 and HDL-3 was determined by isoelectrofocusing in polyacrylamide-urea gel. HDL-2 cholesterol was significantly higher in heavy drinkers (P less than 0.005). A parallel trend for HDL-3 cholesterol was observed. In alcohol consumers HDL-2 particles were enriched in apos C, in particular apo C-II (P 0.005), displacing apo A-I. These data suggest that apolipoprotein distribution in the HDL-2 subfraction is influenced by alcohol intake even at the lowest level.