Atorvastatin increases low-density lipoprotein size and enhances high-density lipoprotein cholesterol concentration in male, but not in female patients with familial hypercholesterolemia

The effects of atorvastatin (Lipitor) were evaluated in 40 patients with familial hypercholesterolemia (FH). Following a 6 week drug-free baseline period 20 male and 20 female patients were treated with atorvastatin 40 mg once daily (QD) for the initial 6 weeks increasing to 80 mg QD during the following 6 weeks. Atorvastatin 40 and 80 mg resulted in a dose related reduction in LDL cholesterol of 44 and 50% (P<0.001), respectively. The reduction of triglycerides (TG) was 35% (P<0.001) with 40 and 80 mg atorvastatin. The lipoprotein lipase and the hepatic lipase activity decreased dose independently by 13% (P<0.05) and 18% (P<0.01), respectively. In males, a dose independent increase in high-density lipoprotein (HDL) cholesterol concentration was observed of 8%, (P<0.05). In females, the HDL cholesterol concentration did not change. Baseline LDL size in the females was significantly larger than in the males, being 268+/-6 A and 264+/-8 A (P<0.05), respectively. In males LDL size increased significantly from 264+/-8 A at baseline to269+/-6 A at 40 mg (P<0.05) and to 270+/-5 A (P<0.05) at 80 mg atorvastatin. In females LDL size did not change upon treatment with atorvastatin 40 and 80 mg QD. In conclusion, atorvastatin has the ability to decrease cholesterol and triglyceride concentrations as well as the activity of both lipoprotein and hepatic lipase activity. Additionally it has a favorable effect on LDL size and HDL cholesterol concentration in male, but not in female FH patients.

Carbohydrate and lipid metabolism during various growth hormone dosing regimens in girls with Turner syndrome. Dutch Working Group on Growth Hormone

To analyze the effects of supraphysiological dosages of growth hormone (GH) on carbohydrate (CH) and lipid metabolism, we investigated 87 girls with Turner syndrome (TS) in two studies: (1) a 4-year GH dose-response (DR) study comparing three groups with stepwise GH dosage increases up to 8 IU/m2/d in girls aged 2 to 11 years, and (2) a 2-year GH administration frequency-response (FR) study in girls aged 11 to 17 years, comparing once-daily (OD) and twice-daily (BID) injections of a total GH dose of 6 IU/m2/d in combination with low-dose ethinyl estradiol (50 ng/kg/d orally). At baseline, impaired glucose tolerance (IGT) was present in 6% of the girls, and at the end of the studies, in 5%. In the DR study, the area under the curve for time-concentration (AUCab) for glucose after an oral glucose tolerance test (OGTT) showed no change over time and no significant difference between any of the study groups. However, in all three DR groups, the AUCab for insulin, fasting glucose, the insulinogenic index, hemoglobin A1c (HbA1c), and urinary C-peptide (uCp) were all significantly higher after 4 years compared with pretreatment (P<.05). In the FR study, group differences were not observed. Compared with healthy Dutch control subjects, the median baseline levels in relatively young girls in the DR study were similar for total cholesterol (TC) and lower for high-density lipoprotein (HDL) cholesterol. In contrast, the median TC levels of relatively older girls in the FR study were higher and HDL levels were similar. With increasing GH dosage in the DR study, median TC and low-density lipoprotein (LDL) levels decreased, whereas median HDL levels increased. The changes after 4 years were significant, including a decrease in the atherogenic index. GH treatment at the supraphysiological dosages used in this study did not increase the frequency of IGT or clinical diabetes. However, we observed an increased insulinogenic index indicative of insulin resistance. Therefore, long-term follow-up study is warranted in these otherwise healthy subjects. OD injection regimens changed the lipid profile toward a more cardioprotective direction with a significant reduction of the TC/HDL cholesterol ratio.

The IGF-I/IGFBP system in congenital partial lipodystrophy

BACKGROUND AND OBJECTIVES

Insulin and IGF-I interact at many levels. Little is known about the insulin-like growth factor-I/insulin-like growth factor binding proteins (IGF-I/IGFBP) system in congenital partial lipodystrophy, a syndrome characterized by insulin resistance, hyperinsulinaemia and absence of truncal and limb fat. Some cases have acromegaloid features with thick skin and large hands and feet in association with normal levels of circulating growth hormone.

METHODS

In four females known with congenital partial lipodystrophy, hyperinsulinaemia with acromegaloid features, the number and affinity of the IGF-I receptors on peripheral blood mononuclear cells (PBMCs), and the concentration of circulating insulin, total and free IGF-I, IGFBP-1 and IGFBP-3 levels were measured in the fasting and the fed state. Cultures of PBMCs of the patients with lipodystrophy were also used to study the effect of IGF-I stimulation on thymidine uptake in vitro.

MEASUREMENTS

In the subjects with lipodystrophy the affinity and the number of the IGF-I receptors on peripheral mononuclear cells (PBMCs) and erythrocytes did not differ significantly from controls in the fasting state. Insulin levels were significantly higher in subjects with lipodystrophy both in the fasting as well in the fed state. Total IGF-I, free IGF-I and IGFBP-3 levels did not differ but serum IGFBP-1 levels were lower in lipodystrophy subjects than in healthy controls. The free IGF-I/IGFBP-1 ratio was increased in lipodystrophy subjects both in the fasting and the fed states. The effects of IGF-I stimulation on thymidine uptake by PBMCs of lipodystrophy subjects in the absence of IGFBP-1 were not different from healthy controls cultures in vitro. When a combination of IGFBP-1 (in a concentration comparable to the fasting serum IGFBP-1 levels in lipodystrophy patients found in our study) and IGF-I was added to PBMC cultures from lipodystrophy patients no decrease in thymidine uptake by PBMCs was found.

CONCLUSIONS

In the four subjects with lipodystrophy hyperinsulinaemia, lowered free IGF-I and IGFBP-1 levels, but increased free IGF-I/IGBP-1 ratios were observed. Low IGFBP-1 concentrations in culture media did not reduce the stimulating IGF-I effect on thymidine uptake by PBMCs from lipodystrophy patients. Our data suggest that the observed increased IGF-I/IGFBP-1 ratio in lipodystrophy patients contributes to an unopposed biological effect of IGF-I on IGF-I receptors, thereby inducing the development of acromegaloid features, acanthosis nigricans and polycystic ovaries in some patients with congenital partial lipodystrophy.

Effects of atorvastatin on serum lipids of patients with familial hypercholesterolaemia

OBJECTIVES

The effects of atorvastatin, a new synthetic HMG-CoA reductase inhibitor, were investigated in patients with familial hypercholesterolaemia (FH), with high LDLc levels whilst on standard treatment.

DESIGN

Open treatment with 40 mg atorvastatin daily for 6 weeks, followed by another 6 weeks with 80 mg atorvastatin.

SETTING

Outpatient lipid clinic of a tertiary referral centre.

SUBJECTS

FH was diagnosed when the untreated LDLc concentration was higher than 6 mmol L-1, tendon xanthomas were present at the participant or a first degree relative, and the family history for hypercholesterolaemia was positive. The FH patients were selected for an LDLc above 5.0 mmol L-1 whilst on standard therapy for at least 3 months. Standard therapy consisted of a diet and 40 mg simvastatin, either alone (n = 17), or in combination with 8-12 g colestyramin (n = 12), or 1800 mg nicotinic acid (n = 12).

MAIN OUTCOME MEASURE

Effects on LDLc concentration.

RESULTS

LDLc concentration significantly decreased during treatment with 80 mg atorvastatin as compared to LDLc levels on 40 mg simvastatin alone or in combination with 8-12 g colestyramin, by 24 +/- 14% (P < 0.01) and 19 +/- 22% (P < 0.01), respectively. LDLc concentration was comparable during treatment with 80 mg atorvastatin or 40 mg simvastatin in combination with 1800 mg nicotinic acid. Atorvastatin was tolerated well, no side-effects were observed.

CONCLUSIONS

Atorvastatin is a valuable addition to the treatment possibilities of patients with serious hypercholesterolaemia, like FH.

Estrogen replacement decreases the level of antibodies against oxidized low-density lipoprotein in postmenopausal women with coronary heart disease

The effect of estrogen replacement therapy (ERT) on plasma lipid concentrations and oxidation parameters was studied in 25 hypercholesterolemic women with coronary heart disease (CHD). During ERT, the low-density lipoprotein cholesterol (LDLc) concentration decreased from 4.31 +/- 0.72 to 3.85 +/- 0.62 mmol/L (P < .01) and high-density lipoprotein cholesterol (HDLc) increased from 1.42 +/- 0.30 to 1.55 +/- 0.33 mmol/L (P < .01). The concentration of autoantibodies against oxidized LDL decreased from 25.9 +/- 22.0 to 22.7 +/- 19.9 mg/L (P < .05), indicating that ERT may have antioxidative effects in vivo. The lag time to oxidation and the LDL subclass pattern did not change. Analysis of the influence of smoking on the efficacy of ERT showed that ERT significantly affected LDLc and HDLc concentrations in 15 nonsmoking women. However, in 10 cigarette smokers, no significant changes in LDLc or HDLc levels were observed. Smoking did not affect the concentration of autoantibodies to oxidized LDL or the lag time. Medroxyprogesterone acetate ([MPA] 10 mg daily) added to ERT decreased HDLc by 9% (P < .01) but did not affect the LDLc level, LDL subclass pattern, or lag time. In conclusion, ERT may have antioxidative effects in vivo and favorably affects dyslipidemia in hypercholesterolemic women with CHD, especially when they refrain from smoking.

Gemfibrozil decreases autoantibodies against oxidized low-density lipoprotein in men with combined hyperlipidaemia

OBJECTIVES

Gemfibrozil is the most widely used fibric acid for the management of combined hyperlipidaemia. It has beneficial effects in the prevention of coronary heart disease (CHD). The mechanisms by which it exerts this effect are not completely resolved. We studied whether gemfibrozil affects low-density lipoprotein (LDL) size and LDL oxidation parameters in males with a moderate combined hyperlipidaemia at high risk for progressive atherosclerosis.

DESIGN

Open treatment with 2 x 600 mg gemfibrozil daily for 12 weeks.

SETTING

Outpatient lipid clinic of a tertiary referral centre.

SUBJECTS

Twenty-three patients with combined hyperlipidaemia and CHD or a positive family history for both CHD and hyperlipidaemia.

MAIN OUTCOME MEASURES

Effects on triglyceride (TG), autoantibodies to oxidized LDL, LDL pattern and resistance to oxidative modification.

RESULTS

During treatment with gemfibrozil, plasma TG concentration decreased from 2.83 +/- 0.85 to 2.02 +/- 0.89 mmol L-1 (P < 0.001). All but one patient were shown to have LDL pattern B. The LDL pattern did not change upon treatment with gemfibrozil. The resistance to oxidation, reflected in the lagtime during in-vitro oxidation slightly decreased from 105 +/- 22 to 99 +/- 18 min (P = 0.01). The concentration of autoantibodies against oxidized LDL indicates the rate of LDL oxidation in vivo. This concentration significantly decreased from 14.2 +/- 9.9 to 13.1 +/- 9.2 mg L-1 (P < 0.01).

CONCLUSIONS

The beneficial effect of gemfibrozil in reducing CHD may at least in part depend on a decrease of the rate of LDL oxidation in vivo.

The additional effects of acipimox to simvastatin in the treatment of combined hyperlipidaemia

OBJECTIVES

Nicotinic acid, an effective drug for treatment of combined hyperlipidaemia, is often not tolerated because of side-effects. Acipimox is a nicotinic acid like lipid lowering drug with less side-effects. We studied whether the addition of acipimox to simvastatin improves the lipid profile in patients with a combined hyperlipidaemia.

DESIGN

Randomized double-blind placebo controlled crossover trial.

SETTING

Outpatient lipid clinic of a tertiary referral centre.

SUBJECTS

Eighteen patients with combined hyperlipidaemia treated with diet and 20-40 mg simvastatin for at least 3 months.

INTERVENTION

Acipimox in a daily dose of 3 X 250 mg for 12 weeks.

MAIN OUTCOME MEASURES

Effects on the concentration of LDLc, TG, HDLc, Lp(a) and Apolipoprotein B, as well as on LDL-size and LDL-resistance to oxidative modification.

RESULTS

Acipimox reduced Lp(a) levels by 8% (P < 0.05). A substantial but not statistically significant change in TG (-32%) and HDLc (+6%) levels was seen. All patients were found to have small dense LDL, with a size of 229 +/- 4 A. LDL size and the resistance to oxidation, reflected in the lag phase during in vitro oxidation, were not affected by the addition of acipimox. In a subgroup of 8 patients with the most severe hypertriglyceridaemia (baseline TG > 4 mmol L- [1]), acipimox induced a significant increase in HDLc (+ 15%, P < 0.01). The effects on TG (-41%), LDLc (-10%) and lag phase (+17%) were also more pronounced than in the group with a lower baseline TG, but none of these changes reached the level of significance.

CONCLUSIONS

Adding acipimox to simvastatin reduced Lp(a) and substantially but not significantly lowered TG. However, in patients with the highest TG levels. HDLc was also significantly improved.

Significance of various parameters derived from biological variability of lipoprotein(a), homocysteine, cysteine, and total antioxidant status

Analytical and biological components of variability and various derived indices have been determined for lipoprotein(a) [Lp(a)], homocysteine (Hcy), cysteine (Cys), and total antioxidant status (TAOS) in ostensibly healthy adult Caucasians and in stable outpatients with an increased serum Lp(a). In healthy Caucasians, average intraindividual biological CVs (CVb) were 20.0% for Lp(a), 9.4% for Hcy, 5.9% for Cys, and 2.8% for TAOS, CVbs being similar in men and women. In the outpatient group, CVbs were comparable for Hcy, Cys, and TAOS, but significantly lower for Lp(a) (7.5% vs 20.0%; P <0.0001). Moreover, a significant inverse relation between both biological and analytical CVs (CVa) and serum Lp(a) concentrations was demonstrated. We conclude that average CVa and CVb values, and hence average derived indices, are adequate for Hcy, Cys, and TAOS, whereas individual values should be used for Lp(a).

Transient hyperlipidemia during treatment of ALL with L-asparaginase is related to decreased lipoprotein lipase activity

A 13-year-old girl with acute lymphoblastic leukemia (ALL) developed extremely high plasma triglyceride (TG) concentrations of 103 mmol/l (reference value <1.8 mmol/l) during combination treatment with corticosteroids and asparaginase. Corticosteroids are known to induce the production of TG-rich particles. On the other hand, corticosteroids increase the activity of lipoprotein lipase (LPL), a key enzyme in the removal of TG from plasma. Generally, the increased LPL activity prevents an extreme rise in TG levels upon therapy with corticosteroids. In our patient, we found that the corticosteroid-induced LPL activity dramatically declined after therapy with L-asparaginase. This suggests that the extensive hypertriglyceridemia in our patient was due to an L-asparaginase-induced decrease in LPL activity. This hypothesis was further supported by the finding that hypertriglyceridemia was less severe when corticosteroids and asparaginase were given separately.

[Hypertriglyceridaemia following oestrogen use]

Three women, aged 52, 54 and 30 years, presented with severe hypertriglyceridaemia. One had suffered pancreatitis. All three used oral oestrogens as replacement therapy or as anticonceptive agent. After cessation of the oral oestrogen mild hypertriglyceridaemia persisted, indicating a pre-existent abnormality in their triglyceride metabolism, in these cases non-insulin-dependent diabetes mellitus, familial combined hyperlipidaemia and familial hypertriglyceridaemia, respectively.

Growth hormone restores hepatic lipase mRNA levels but the translation is impaired in hepatocytes of hypothyroid rats

During hypothyroidism, hepatic lipase (HL) activity is decreased. The low HL may be due to thyroid hormone insufficiency or to the concomitant fall in growth hormone (GH) activity. We studied HL expression in hepatocytes freshly isolated from hypothyroid rats with and without additional GH-substitution. In all animals HL mRNA was detected by RT-PCR in the hepatocytes, but not in the non-parenchymal cells. In hypothyroid cells HL mRNA levels were reduced by 40%, and the in vitro secretion of HL-activity and HL-protein was decreased by about 50%. In cells from GH-substituted hypothyroid rats, HL mRNA level was normalised, but the secretion of HL remained low. The specific enzyme activity of secreted HL was similar under all conditions. The discrepancy between HL mRNA and HL secretion in GH-supplemented rats may be due to (post)translational effects. Therefore we studied the HL synthesis and maturation in hepatocytes from hypothyroid and GH-substituted rats. Pulse-labelling experiments with [(35)S]methionine showed that the incorporation of [(35)S]methionine into HL protein was lower both in hypothyroid cells and in GH-supplemented cells than in control cells. During the subsequent chase, the intracellular processing and transport of newly synthesized HL protein in the hepatocytes from hypothyroid rats, whether or not supplemented with GH, was similar to control cells. We conclude that in livers of hypothyroid, GH-substituted rats translation of HL mRNA is inhibited despite restoration of HL mRNA levels.

The additional effects of acipimox to simvastatin in the treatment of combined hyperlipidaemia

OBJECTIVES

Nicotinic acid, an effective drug for treatment of combined hyperlipidaemia, is often not tolerated because of side-effects. Acipimox is a nicotinic acid like lipid lowering drug with less side-effects. We studied whether the addition of acipimox to simvastatin improves the lipid profile in patients with a combined hyperlipidaemia.

DESIGN

Randomized double-blind placebo controlled crossover trial.

SETTING

Outpatient lipid clinic of a tertiary referral centre.

SUBJECTS

Eighteen patients with combined hyperlipidaemia treated with diet and 20-40 mg simvastatin for at least 3 months.

INTERVENTION

Acipimox in a daily dose of 3 x 250 mg for 12 weeks.

MAIN OUTCOME MEASURES

Effects on the concentration of LDLc, TG, HDLc, Lp(a) and Apolipoprotein B, as well as on LDL-size and LDL-resistance to oxidative modification.

RESULTS

Acipimox reduced Lp(a) levels by 8% (P < 0.05). A substantial but not statistically significant change in TG (-32%) and HDLc (+6%) levels was seen. All patients were found to have small dense LDL, with a size of 229 +/- 4 A. LDL size and the resistance to oxidation, reflected in the lag phase during in vitro oxidation, were not affected by the addition of acipimox. In a subgroup of 8 patients with the most severe hypertriglyceridaemia (baseline TG < 4 mmol L- [1]), acipimox induced a significant increase in HDLc (+15%, P < 0.01). The effects on TG (-41%), LDLc (-10%) and lag phase (+17%) were also more pronounced than in the group with a lower baseline TG, but non of these changes reached the level of significance.

CONCLUSIONS

Adding acipimox to simvastatin reduced Lp(a) and substantially but not significantly lowered TG. However, in patients with the highest TG levels, HDLc was also significantly improved.

Hypertriglyceridemia enhances monocyte binding to endothelial cells in NIDDM

OBJECTIVE

The mechanisms by which diabetes leads to rapidly progressive atherosclerosis are not fully understood. Adherence of monocytes to the arterial wall is an early event in the development of atherosclerotic lesions.

RESEARCH DESIGN AND METHODS

The binding of freshly isolated monocytes from patients with NIDDM, IDDM, and healthy control subjects to a monolayer of endothelial cells obtained from human umbilical vein was investigated.

RESULTS

Endothelial adherence of monocytes from normolipidemic patients with IDDM (15.8 +/- 4.5%) or NIDDM (16.9 +/- 4.6%) was comparable to that of monocytes from a control population (15.3 +/- 3.5%). In patients with NIDDM with a serum triglyceride concentration > 2.5 mmol/l, the percentage of cells that adhere to endothelial cells in vitro was significantly increased (23.3 +/- 3.1%). Glycemic control did not correlate with monocyte adherence. The presence of symptomatic atherosclerotic disease, age, or sex was not associated with a change in monocyte binding in vitro.

CONCLUSIONS

The results suggest that in NIDDM hypertriglyceridemia should be treated to reduce the high risk for atherosclerosis.

Lipoprotein(a) in patients with acute cerebral ischemia

BACKGROUND AND PURPOSE

In several cross-sectional studies, a high serum lipoprotein(a) [Lp(a)] level was found to be an independent risk factor for cerebral infarction. In a recent prospective study, however, no association was found between Lp(a) levels at baseline and future risk of stroke. Whether Lp(a) is a prognostic factor in a high-risk population of patients with acute ischemic stroke remains unclear.

METHODS

We assessed Lp(a) level on admission to study its relationship with cardiovascular risk profile, stroke severity, and prognosis in 151 consecutive patients with acute cerebral ischemia. The mean follow-up period was 2.5 +/- 1.2 years. Lp(a) was measured by means of a solid-phase two-site immunoradiometric assay.

RESULTS

Increased Lp(a) levels were found in 53 (35%) of the patients with cerebral ischemia. Median (5th and 95th percentile) values of Lp(a) were 191 (12 and 1539) mg/L and 197 (10 and 1255) mg/L for patients with transient ischemic attack and patients with ischemic stroke, respectively. No relationship was found between Lp(a) levels and stroke severity (P=.68) or the occurrence of vascular events during follow-up (P log rank=0.81).

CONCLUSIONS

We conclude that Lp(a) is increased in about one third of patients with acute cerebral ischemia, but it does not appear to be associated with the cardiovascular risk profile, stroke characteristics, or the prognosis of such patients.

Growth hormone normalizes low-density lipoprotein receptor gene expression in hypothyroid rats

Hypothyroidism leads to a decreased activity of the low-density lipoprotein (LDL) receptor, which contributes to the hypercholesterolemia frequently seen during hypothyroidism. It is not known whether the decreased activity of the LDL receptor is directly due to the absence of thyroid hormone, or secondary to a deficiency of growth hormone (GH). Therefore, the effect of GH administration on LDL receptor activity was studied in hypothyroid rats. Following induction of hypothyroidism, the level of LDL receptor mRNA was significantly decreased in liver homogenates to 31 % +/- 6% of the control value. LDL binding to liver cell membranes and plasma membranes decreased during hypothyroidism to approximately 65% of the control value. The effect of hypothyroidism on the hepatic LDL receptor was reflected in a significantly increased half-life of (125)I-LDL of 29 hours in controls versus 48 hours in hypothyroid rats. Treatment of hypothyroid rats with human GH (hGH) resulted in normalization of both the amount of hepatic LDL receptor mRNA and LDL binding on liver cell membranes. The plasma half-life of human (125)I-labeled LDL decreased during GH substitution but did not normalize. GH treatment significantly reduced plasma LDL cholesterol levels by 36% (P < .05, n = 8), to levels that were still higher than in control animals. These data indicate that at least part of the decreased LDL receptor activity during hypothyroidism is secondary to GH deficiency.

Oral physiological magnesium supplementation for 6 weeks with 1 g/d magnesium oxide does not affect increased Lp(a) levels in hypercholesterolaemic subjects

Twenty hyperlipidaemic patients on a cholesterol-poor diet were selected on the basis of a raised lipoprotein (a) (Lp(a); apo (a) > 300 U/litre) and treated with 1000 mg MgO per day during 6 weeks. Serum magnesium slightly increased compared to pretreatment levels (P < 0.001). Serum apo(a) concentrations (mean +/- S.D.) were not affected: pretreatment level 963 +/- 552 U/litre; during treatment 999 +/- 536 U/litre; and after washout 995 +/- 524 U/litre. Serum cholesterol increased slightly during MgO treatment because of an increase in LDL-cholesterol (10 per cent) and returned to pretreatment levels after a washout period.

Performance of a direct, immunoseparation based LDL-cholesterol method compared to Friedewald calculation and a polyvinyl sulphate precipitation method

The analytical performance of a direct, immunoseparation based LDL-cholesterol method (Genzyme Corporation) was evaluated on an ELAN analyser (Merck), and compared with the performance of routinely used methods (LDL-cholesterol estimated by the Friedewald equation, and LDL-cholesterol obtained after polyvinyl sulphate precipitation). Within-day coefficients of variation (CVs) were 0.79 to 2.51% for immunoseparation based LDL-cholesterol; the between-day CVs varied between 2.62 and 3.89%, i.e. within the recommended National Cholesterol Education Program (NCEP) goal of < 4%. A method comparison study, according to the National Committee for Clinical Laboratory Standards (NCCLS) EP9-P guidelines, was performed using fasting normo- and hypertriacylglycerolaemic as well as cholestatic sera. In fresh normotriacylglycerolaemic sera immunoseparation based LDL-cholesterol (y) and Friedewald LDL-cholesterol (x) values were identical as slope and intercept of the Passing & Bablok regression equation were not significantly different from one and zero, respectively (y = 1.006 x -0.107; N = 45). In contrast, immunoseparation based LDL-cholesterol (y) differed significantly from polyvinyl sulphate LDL-cholesterol (x) results (y = 0.922 x + 0.234; N = 103). Freezing normotriacylglycerolaemic sera (three weeks, -20 degrees C) resulted in a negative bias of -5.8% for the immunoseparation based LDL-cholesterol method, and in a positive bias of +5.3% for the polyvinyl sulphate method, compared to fresh specimens. Immunoseparated LDL-cholesterol was completely recovered up to at least 37.84 mmol/l serum triacylglycerols. We conclude that the immunoseparation based LDL-cholesterol method is a practical, not technically demanding technique well applicable within routine clinical laboratories.(ABSTRACT TRUNCATED AT 250 WORDS)

Monocytes from patients with combined hypercholesterolemia-hypertriglyceridemia and isolated hypercholesterolemia show an increased adhesion to endothelial cells in vitro: II. Influence of intrinsic and extrinsic factors on monocyte binding

One of the primary risk factors for atherosclerosis is hypercholesterolemia. Patients with isolated hypercholesterolemia or combined hypercholesterolemia-hypertriglyceridemia are at risk to develop premature atherosclerosis. Diet-induced hypercholesterolemia in animals leads to an increased adhesion of monocytes to and transmigration through the intact endothelium of the vessel wall. In the present study, we investigated in vitro binding of freshly isolated monocytes from patients and healthy controls to a monolayer of endothelial cells obtained from human umbilical vein. All four diagnosed patient groups with isolated or combined hypercholesterolemia showed a significant increase in monocyte binding as compared with the control group (familial hypercholesterolemia [FH], +41%; polygenic hypercholesterolemia [PH] +35%; familial combined hypercholesterolemia [FCH], +47%; nonfamilial combined hypercholesterolemia-hypertriglyceridemia [CHH], +67%). In a longitudinal study it was observed that diet or medication induced a decrease in cholesterol and triglycerides; however, these therapeutic conditions did not diminish in vitro monocyte binding in the patient groups. There was no correlation between monocyte binding and plasma cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, or lipoprotein(a) within hyperlipidemic patient groups. The presence of heart and vessel disease in hyperlipidemic patients was not associated with a change in monocyte binding. The adhesion to endothelial cells of monocytes from smoking patients with combined hypercholesterolemia (27%) was significantly higher (+23%) than that of monocytes from nonsmoking patients. Cytofluorimetric analysis of monocytes from FCH and CHH patients for specific monocyte differentiation markers and integrins did not show differences as compared with monocytes from healthy controls.

Hyperglycemia in the acute phase of stroke is not caused by stress

BACKGROUND AND PURPOSE

Hyperglycemia in the acute phase of stroke is associated with poor outcome. Whether hyperglycemia in nondiabetic stroke patients is caused by stress is controversial.

METHODS

We studied glucose levels and glycosylated hemoglobin in 91 consecutive patients with acute stroke admitted within 24 hours after onset of symptoms. In 27 unselected patients we also measured catecholamines on days 1 and 3 after onset.

RESULTS

Hyperglycemia was found in 39 (43%) of the patients, 55% of whom either had diabetes mellitus or latent diabetes; the others had idiopathic hyperglycemia. Norepinephrine levels were associated with the severity of the stroke (P = .005) and with hypertension (P = .03) but not with glucose levels, irrespective of whether or not the patients had diabetes.

CONCLUSIONS

We conclude that hyperglycemia in the acute phase of stroke cannot be explained by increased stress.

Growth hormone normalizes hepatic lipase in hypothyroid rat liver

The effects of growth hormone (GH) administration on hepatic lipase (HL) activity and mRNA levels were studied in pair-fed hypothyroid rats. In the hypothyroid state, liver HL mRNA levels and liver and postheparin plasma HL activities were decreased. In hypothyroid rats, GH normalized HL mRNA levels and HL activity in postheparin plasma; GH also increased the activity of HL in the liver, which remained lower than that in controls. These data indicate that at least part of the decrease of HL activity during hypothyroidism is due to the concomitant GH deficiency, and that GH rather than thyroid hormone may regulate HL mRNA levels.