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BACKGROUND: Omega-3 polyunsaturated fatty acids (long-chain ω-3 PUFA) have proved to be beneficial in atherosclerosis, arrhythmia and hypertriglyceridemia in several studies, which has led national and international societies to recommend an intake of 1 g/d long-chain ω-3 PUFA for antiatherosclerotic and antiarrhythmic purposes or 2–4 g/d for a lipid lowering effect. Numerous preparations are marketed for supplementing western diet, which is low in long-chain ω-3 PUFA. Since these preparations vary in their long-chain ω-3 PUFA content, we tested nine commercially available products for their fatty acid composition. METHODS: Nine commercially available ω-3 fatty acid supplements were analyzed using capillary gas chromatography to determine their fatty acid content. RESULTS: The nine preparations showed huge differences, up to 63.7 ± 1.58 mol% (P = 0.002), in their longchain ω-3 fatty acid content. Most of them failed to achieve the daily recommended dose of 1 g, even when administered at the highest dosage according to the manufacturer's recommendations. Eight of the preparations contained either equal or significantly greater amounts of long-chain ω-3 PUFA than denoted by the manufacturer; one preparation did not provide any information. The highest percentage of DHA and EPA was detected in Omacor® (95.80 ± 0.63%) and Percucor® (76.8 ± 7.109%). CONCLUSION: Administering long-chain ω-3 fatty acid preparations may result in huge differences in terms of the actual amount ingested. It is therefore advisable to use the most standardized and purified products available.

Cathelicidins are mammalian proteins containing a C-terminal cationic antimicrobial domain. Porcine PR-39 cathelicidin affects leukocyte biology. Mechanisms of action may involve alteration of heparan sulfate proteoglycan-dependent functions in inflammatory cells. It was tested whether PR-39 affects human neutrophil migration and if such effects involve heparan sulphate proteoglycans. Neutrophils were from forearm venous blood of healthy donors. Migration was tested in modified Boyden chamber assays. Involvement of heparan sulfate proteoglycans was tested by their chemical modification and by the use of specific antibodies. PR-39 induced migration in neutrophils in a concentration dependent manner. Modification of heparan sulfate proteoglycans with sodium chlorate inhibited migration whereas chemotaxis toward the chemoattractant formyl-Met-Leu-Phe was not affected. Removal of heparan sulfates or chondroitin sulfates from the surface of neutrophils by heparinase or chondroitinase inhibited migration toward PR-39. In conclusion, antimicrobial PR-39 stimulates human neutrophil chemotaxis in a heparan sulfate proteoglycan-dependent manner. Involvment of syndecans is likely as both heparinase and chondroitinase were abrogating. Data suggest active participation of heparan sulfate proteoglycans of neutrophils in cathelicidin peptide-mediated regulation of the antimicrobial host defense.

Objective Phospholipid transfer protein (PLTP) facilitates cholesterol efflux from cells, intravascular HDL remodelling and transfer of vitamin E and endotoxin. In humans, the relationship of PLTP to atherosclerosis is unknown. However, strong coronary risk factors like obesity, diabetes, cigarette smoking and inflammation increase circulating levels of active PLTP. The aim of the present, cross-sectional study was to analyze the relationship of PLTP to peripheral arterial disease, a marker of generalized atherosclerosis, independently of potentially confounding factors like obesity, diabetes and smoking. Methods We performed a case control study in 153 patients with symptomatic peripheral arterial disease (PAD) and 208 controls free of vascular disease. Smokers and patients with diabetes mellitus were excluded. A lipoprotein-independent assay was used for measurement of circulating bioactive PLTP and an ELISA utilizing a monoclonal antibody was used to analyze PLTP mass. Results PLTP activity was significantly decreased in patients with PAD 5.5 (4.6–6.4)(median (25th–75th percentile)) versus 5.9 (5.1–6.9) μmol/mL/h in controls ( p = 0.001). In contrast, PLTP mass was similar in patients with PAD 8.5 μg/mL (7.3–9.5) and in controls 8.3 μg/mL (6.9–9.7) ( p = 0.665). Multivariate logistic regression analysis revealed that PLTP activity is independently associated with the presence of PAD. PLTP activity was similar in patients with and without lipid-lowering drugs ( p = 0.396). Conclusion Our results show that in non-diabetic, non-smoking subjects low rather than high PLTP activity is a marker for the presence of peripheral arterial disease and that distribution of PLTP between high-activity and low-activity forms may be compromised in atherosclerosis.

Antipsychotika der neuen Generation verdrangen vermehrt die klassischen Antipsychotika, vor allem wegen des geringeren Risikos Nebenwirkungen des extrapyramidalmotorischen Systems hervorzurufen und aufgrund einiger therapeutischer Vorteile. Die Verwendung der Antipsychotika der neuen Generation wird jedoch vermehrt mit starker Gewichtszunahme, der Induktion einer Insulinresistenz und eines atherogenen Lipidprofils assoziiert. Unter diesen Substanzen fuhren Clozapin und Olanzapin zur starksten Gewichtszunahme, hauptsachlich uber eine Vermehrung des Korperfettes, und zu Veranderungen der Glukosehomoostase. In den meisten Fallen trat ein Diabetes mellitus bereits innerhalb von Tagen bis Wochen nach Therapiebeginn mit diesen Antipsychotika auf, in den meisten Fallen waren die neu aufgetretenen Storungen der Glukosehomoostase nach Absetzen der Medikation reversibel und einige Berichte beschreiben ein erneutes Auftreten bei neuerlicher Behandlung mit derselben Medikation. Ein moglicher Pathomechanismus fur die Entstehung einer Hyperglykamie unter Therapie mit Antipsychotika der neuen Generation stellt die Beeintrachtigung der Insulinwirkung uber humorale und/oder zellulare Mechanismen dar. Alternativ konnte ein durch Antipsychotika induzierter Diabetes mellitus sekundar durch eine Gewichtszunahme entstehen oder infolge einer Veranderung der Fettverteilung, insbesondere einer Vermehrung der viszeralen Fettdepots, oder durch eine direkte Wirkung an insulinsensitiven Geweben. In diesem Artikel geben wir einen Uberblick uber die metabolischen Nebenwirkungen unter der Therapie mit Antipsychotika der neuen Generation, versuchen den Pathomechanismus dieser Nebenwirkungen zu beleuchten und mochten mogliche zukunftige Therapieansatze darstellen und diskutieren.

The ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) is an inhibitor of the insulin receptor. Variants of ENPP1 are associated with infantile arterial calcification, obesity, and insulin resistance. To study the functional relevance of this protein in vivo, we cloned rabbit ENPP1 and studied its regulation in experimentally induced diabetes mellitus. We amplified and sequenced the complete coding sequence of rabbit ENPP1 gene out of a liver cDNA library using redundant primers deduced from other species. Next, we performed quantitative PCR of ENPP1 to study the tissue distribution of ENPP1 expression and its regulation in an alloxan-dependent diabetes model. The putative rabbit ENPP1 protein contains 873 amino acids and is highly conserved when compared with human ENPP1 (90% amino acid identity). Particularly high levels of ENPP1 mRNA expression were found in adipose tissue. Quantitative PCR analysis revealed a significant upregulation of ENPP1 transcription in liver (p = 0.025) and brain (p = 0.034) of diabetic rabbits compared with controls. Hepatic ENPP1 expression is induced in diabetic rabbits when compared with controls. This approximately twofold upregulation of ENPP1 mRNA in rabbit liver parallels previous findings in patients with type 2 diabetes mellitus. We provide further molecular information about ENPP1 as a potential pharmacologic target and characterize its regulation in an insulin-dependent diabetes mellitus animal model.

Typical Western diets cause postprandial lipaemia for 18 h per day. We tested the hypothesis that postprandial lipaemia decreases insulin sensitivity.Employing a randomised crossover design, we administered two types of virtually isocaloric meals to ten healthy volunteers on two separate occasions. The meals (Meals 1 and 2) were both designed to produce a rise in triglycerides, but only Meal 1 generated a rise in NEFA, too. Insulin sensitivity, as quantified by an IVGTT with minimal model analysis, was calculated postabsorptively at 08.00 h and postprandially at 13.00 h, i.e. 3 h after meal ingestion.Triglycerides rose from 0.91+/-0.31 mmol/l postabsorptively to 2.08+/-0.70 mmol/l postprandially with Meal 1 (p=0.005) and from 0.92+/-0.41 to 1.71+/-0.79 mmol/l with Meal 2 (p=0.005). Neither the triglyceride levels at 13.00 h, nor the post-meal AUCs for triglycerides were statistically different between Meal 1 and Meal 2. NEFA rose from 0.44+/-0.17 mmol/l postabsorptively to 0.69+/-0.16 mmol/l postprandially with Meal 1 (p=0.005) and showed no significant change with Meal 2 (0.46+/-0.31 mmol/l postabsorptively vs 0.36+/-0.32 mmol/l postprandially, p=0.09). Both the NEFA level at 13.00 h and the post-meal AUC for NEFA were significantly higher after Meal 1 than Meal 2. Compared with the postabsorptive state, insulin sensitivity decreased postprandially after each of the two meals to a comparable degree (Meal 1: -53%, p=0.02; Meal 2: -45%, p=0.005).Our study reveals a drop in insulin sensitivity during postprandial lipaemia and strongly suggests that decreased insulin sensitivity is brought about by elevated plasma levels of triglyceride-rich lipoproteins independently of plasma NEFA levels.

The protein C pathway is an important regulator of the blood coagulation system. Protein C may also play a role in inflammatory and immunomodulatory processes. Whether protein C or activated protein C affects lymphocyte migration and possible mechanisms involved was tested. Lymphocyte migration was studied by micropore filter assays. Lymphocytes that were pretreated with protein C (Ceprotin) or activated protein C (Xigris) significantly reduced their migration toward IL-8, RANTES, MCP-1, and substance P, but not toward sphingosine-1-phosphate. The inhibitory effects of protein C or activated protein C were reversed by Abs against endothelial protein C receptor and epidermal growth factor receptor. Evidence for the synthesis of endothelial protein C receptor by lymphocytes is shown by demonstration of receptor mRNA expression and detection of endothelial protein C receptor immunoreactivity on the cells’ surface. Data suggest that an endothelial protein C receptor is expressed by lymphocytes whose activation with protein C or activated protein C arrests directed migration. Exposure of lymphocytes to protein C or activated protein C stimulates phosphorylation of Tyr845 of epidermal growth factor receptor, which may be relevant for cytoprotective effects of the protein C pathway.

Scavenger receptor class B type I (SR-BI) has been shown to be expressed in human atherosclerotic plaque macrophages, where it is believed to reduce atherosclerosis by promoting cholesterol efflux. In this study we investigated the influence of aspirin and other NSAIDs on SR-BI expression and function in cultured human macrophages as well as in different mouse strains. Incubation of human macrophages with 0.5 mmol/l aspirin resulted in increased SR-BI protein expression and increased uptake of HDL-associated [3H]cholesteryl oleate without changes of SR-BI mRNA levels. In contrast, using 5 mmol/l of aspirin, SR-BI expression and function were significantly decreased. Sodium salicylate exerted similar effects on SR-BI expression, whereas no effects were observed using known COX1/2 inhibitors ibuprofen and naproxen, respectively. In in vivo studies low-dose aspirin treatment (6 mg/kg.day) induced SR-BI expression in wild-type and PPAR-alpha knockout mice, respectively, whereas the opposite effect was observed upon high-dose aspirin treatment (60 mg/kg.day) in these animals. We could show that COX-independent effects of aspirin were able to enhance expression of SR-BI in macrophages in a post-transcriptional, PPAR-alpha independent way, suggesting a novel pharmacologic effect of aspirin.

Background. Hepatic lipase plays a key role in the metabolism of pro-atherogenic and anti-atherogenic lipoproteins affecting their plasma level as well as their physico-chemical properties. We hypothesized single nucleotide polymorphisms in the promoter region of the hepatic lipase gene to be associated with an increased risk for peripheral arterial disease (PAD). Methods. A total of 241 patients with PAD and 241 controls matched for sex and age (±2 years) were genotyped cross-sectionally for the −250 single nucleotide polymorphism in the hepatic lipase promoter. Results. The frequency for the −250A allele in patients with PAD was 0.203, whereas it was 0.147 in the controls (P = 0.022). Hepatic lipase promoter polymorphism distribution remained significantly different between cases and controls after multivariate logistic regression analysis (P = 0.021). The odds ratio of the −250A hepatic lipase allele for the PAD was 1.69 (95% confidence interval of 1.08–2.64), when adjusted for current smoking, arterial hypertension, cholesterol, triglycerides, HbA1C, total homocysteine and high sensitivity C-reactive protein. Conclusion. Previous data in patients with ischaemic heart disease have suggested a pro-atherogenic role of low hepatic lipase levels. Our results extend these data to the vascular territory of the lower limbs, such that hepatic lipase promoter variation represents a genetic risk factor of PAD.

After an ischemic event vascular growth factors are involved in regulating leukocyte infiltration in inflammatory processes. This study focused on effects of 2 other angiogenic growth factors, angiopoietin-1 and angiopoietin-2, on human neutrophils and on the involvement of the angiopoietin receptor Tie-2.Neutrophils were from venous blood of healthy donors and cell migration was studied by micropore filter assays. Receptor expression was investigated by reverse transcriptase-polymerase chain reaction (PCR) for mRNA and fluorescence-activated cell-sorter scanner (FACS) analysis. Signaling mechanisms required for angiopoietin-dependent effects were tested functionally by using signaling enzyme blockers.The angiopoietins were chemotactic for neutrophils. They showed antagonistic effects on each other and both inhibited VEGF-directed migration of neutrophils. The effects of both angiopoietins were Tie-2 dependent. Tie-2 receptor immunoreactivity was confirmed on neutrophils by FACS. De novo synthesis is suggested by Tie-2 receptor mRNA expression as demonstrated by reverse transcriptase PCR.Data suggest that a Tie-2 receptor is expressed by human neutrophils whose active site ligation with either angiopoietin-1 or angiopoietin-2 exerts migratory effects on the one hand and arrests VEGF-mediated chemotaxis on the other. These effects suggest a role of angiopoietins in modulating neutrophilic inflammation.

The prevalence of obesity is rising worldwide dramatically, affecting up to 50 percent of the population. The epidemic of obesity leads to a marked increase in the metabolic syndrome, a cluster of cardiovascular risk factors characterized by visceral obesity, insulin resistance, low HDL-Cholesterol, hypertriglyceridemia, and a subclinical proinflammatory state. In the last years, the NCEP and the WHO highlighted and defined the key features of the metabolic syndrome to facilitate the clinical diagnosis and preventive interventions. The conservative therapy of obesity and the metabolic syndrome by life style intervention and pharmacological interventions leads only to moderate weight loss with inconstant long-term success. Intervention by bariatric surgery can serve as a model for the metabolic effects of permanent weight loss. In several studies the pronounced weight loss induced a reduction of almost all components of the metabolic syndrome, including glucose and lipid status and is followed by an improvement in the quality of life. Recent research suggested a decrease in mortality rate in addition to cost effectiveness of bariatric surgery.

The magnitude of postprandial lipemia has been identified as independent risk factor for the development of coronary artery disease. To test the effect of postprandial versus postabsorptive low-density lipoproteins (LDL) on the expression of adhesion molecules, LDL were isolated from healthy subjects before and 4 h after ingestion of a standardized fatty test meal. We used flow cytometry and Northern blotting to quantify cell adhesion molecules in human aortic endothelial cells (HAEC). The adherence of leukocytes to HAEC was analyzed using a monocyte adhesion assay. Incubation of HAEC with postprandial, but not postabsorptive LDL induced a two-fold increase in the surface expression of intercellular adhesion molecule-1 (ICAM-1), but not of E-selectin or vascular cell adhesion molecule-1. In addition, increased amounts of ICAM-1 transcripts were found in HAEC treated with postprandial LDL. The adhesion of monocytes to HAEC was enhanced after pretreatment with postprandial, but not with postabsorptive LDL. We conclude that postprandial, but not postabsorptive LDL increase the surface expression of ICAM-1 in HAEC apparently by de novo protein synthesis leading to increased adhesion of monocytes. The upregulation of ICAM-1 by postprandial LDL may explain part of the proatherogenic effect of high postprandial lipemia.

Scavenger receptor class B type I (SR-BI), a CD36 family member, plays a key role in high-density lipoprotein (HDL) metabolism, reverse cholesterol transport, and whole body cholesterol homeostasis, and is shown to be involved in the development of atherosclerosis in mice. In this report, we describe the effects of the adenoviral overexpression of human SR-BI (hSR-BI) in New Zealand White (NZW) rabbits, a wild-type animal model that expresses cholesteryl ester transfer protein (CETP) in plasma, displays a manlike lipoprotein profile, and is susceptible to atherosclerosis. A total of 1x10(12) adenoviral particles containing either hSR-BI or lacZ complementary deoxyribonucleic acid (control) were infused into the ear vein of NZW rabbits. Transgene expression was ascertained by TaqMan Real Time polymerase chain reaction measurements. Rabbits infected with Ad/hSR-BI (adenoviral plasmids containing hSR-BI) showed a faster clearance of administered [3H]HDL cholesterol and significantly decreased apolipoprotein (apo) A-I levels when compared to control rabbits, respectively. Interestingly, we found markedly increased levels of low-density lipoprotein (LDL) cholesterol exclusively in SR-BI-overexpressing rabbits. These changes were not accompanied by alterations in LDL receptor expression but by increased levels of CE transfer in these animals. By lowering HDL cholesterol and increasing plasma apoB-containing lipoprotein levels, the overexpression of SR-BI leads to a lipoprotein pattern, which is believed to enhance the development of atherosclerosis. The role of SR-BI in lipoprotein metabolism and atherogenesis in rabbits--a CETP-expressing animal model displaying a manlike lipoprotein profile--may therefore be different from the one found in rodents.

Obesity is associated with increased morbidity and mortality from atherosclerotic disease. Nontraditional cardiovascular risk factors such as C-reactive protein (CRP) and interleukin-6 (IL-6) are elevated in obese subjects and weight loss is associated with an attenuation of these risk factors. Matrix metalloproteinase-9 (MMP-9) has been linked to plaque rupture, and is, thus, a candidate marker of future myocardial events. The aim of this study was to determine the influence of weight loss on MMP-9 plasma concentrations.CRP, IL-6 and MMP-9 were analyzed from samples of 45 morbidly obese, middle-aged women before gastric banding and 1 y postsurgical treatment in this prospective study. The body mass index (BMI) of subjects decreased from 42.5+/-4.9 to 32.3+/-5.3 kg/m(2) 1 y after gastric banding. In parallel, both MMP-9 and CRP were reduced by 23 and 41%, respectively. A positive relationship was found between BMI and MMP-9 (r=0.312, P0.05), and between CRP and IL-6 (r=0.508, P0.05), whereas no correlation was found between CRP and MMP-9.We conclude that weight loss is associated with a pronounced decrease in the nontraditional cardiovascular risk markers MMP-9 and CRP, which could indicate future beneficial effects of weight loss on the cardiovascular risk in weight loosing subjects.

Tyrosine kinases are known to play a critical role in the regulation of leukocyte function. Antithrombin mediates its effects via syndecan-4 which is known to be linked to the Src tyrosine kinases. In this study, we investigated the role of Src tyrosine kinases in antithrombin-regulated leukocyte migration and Src tyrosine kinase phosphorylation in response to stimulation with antithrombin. Neutrophils and monocytes obtained from forearm venous blood were pre-treated by various Src-family selective tyrosine kinase inhibitors with or without antithrombin followed by washing and assessment of their migratory response toward antithrombin, interleukin-8, or RANTES using Boyden microchemotaxis chambers. Activation status of the two major Src tyrosine kinase phosphorylation sides Tyr416 and Tyr527 was tested using Western blot analysis. Dose-dependent reversal of the antithrombin-mediated effects on neutrophil and monocyte migration was induced by the selective Src kinase inhibitors PP1 and PP2. In Western blot analyses, antithrombin increased Tyr416 and decreased Tyr527 phosphorylation of Src tyrosine kinases in a time- and dose-dependent manner. Moreover, co-incubation with antithrombin lowered the level of RANTES-induced Tyr416 phosphorylation. Therefore, Src tyrosine kinases linked to signaling of antithrombin-binding sites on leukocytes may play an important role in modulating effects on cells function.

OBJECTIVE: Dyslipidaemia in obesity is characterized by hypertriglyceridaemia, low HDL-C levels, small, dense HDL particles and increased phospholipid transfer protein (PLTP) activity. METHODS: In the present study, we investigated PLTP activity and HDL particle size in 16 morbidly obese, middle-aged women, who underwent Swedish Adjustable Gastric Banding surgery. Study subjects were tested within 2 months before and 1 y after surgery. PLTP activity was determined by exogenous substrate assay and HDL particle size by gradient gel electrophoresis, respectively. RESULTS: Pronounced weight loss after gastric banding surgery resulted in a significant decrease of PLTP activity from 8.42±2.04 to 7.43±2.21 μmol/ml/h (P=0.02). The size of HDL2 particles increased signficantly from 14.04±0.86 to 14.28±0.64 nm (P=0.02) after body weight reduction, while no change in HDL3 particle size was apparent. DISCUSSION: Our results suggest that dyslipidaemia in obesity is—at least partially—reversible by weight loss. We hypothesize that reduction of PLTP activity and increase of HDL particle size are important component factors in converting the atherogenic lipoprotein profile of obese subjects into a less atherogenic profile with weight loss.

Cell adhesion molecules (CAM) play an important role in the pathogenesis of atherosclerosis by mediating the binding of leukocytes to the endothelium. Soluble CAM isoforms are known to be elevated in the sera of patients suffering from coronary artery disease (CAD).We measured the concentrations of soluble intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, P-selectin, platelet endothelial cell adhesion molecule-1, and highly sensitive C-reactive protein (hs-CRP) in the blood of 47 CAD patients before and 6 months after starting statin therapy and in 16 untreated CAD patients. The progression of CAD was monitored by calculating the coronary calcium score using electron beam computed tomography.Soluble P-selectin (92+/-11 ng/ml vs. 59 +/- 4 ng/ml, p0.0001) and hs-CRP (0.92 +/- 0.14 mg/dl vs. 0.42 +/- 0.11 mg/dl, p0.001) decreased significantly in the statin-treated group compared to baseline levels. None of the other proteins studied showed significant changes. In contrast to hs-CRP, the reduction of soluble P-selectin concentrations correlated directly with the lowering of total cholesterol (r(2) = 0.236, p0.005) and inversely with the progression of CAD (r(2) = 0.393, p0.0001).Our results suggest P-selectin as an additional marker for the beneficial action of statins in patients with CAD.

Background Thrombin downregulates endothelial ectonucleotidase activity resulting in high levels of adenosine diphosphate (ADP) and adenosine triphosphate (ATP) which lead to platelet, leukocyte and endothelial activation. Depending on adenosine nucleotide levels, resting platelets inhibit and thrombin-activated platelets increase respiratory burst of neutrophils. Whether the red wine polyphenols quercetin and resveratrol affect thrombin-dependent adenosine nucleotide, metabolism and thrombin-induced signaling is unknown. Materials and methods ATP and ADP secretion by platelets, the impact on subsequent oxidative burst activity in neutrophils and CD39/ATPdase function in endothelial cells (ECs)was studied. Cell migration was measured in modified Boyden chambers; adenosine metabolites were quantified by high-performance liquid chromatography (HPLC). Signal transduction was studied by Western blotting. Results Quercetin and resveratrol inhibited thrombin-induced ADP and ATP secretion from platelets in a concentration-dependent manner. Augmented respiratory burst of neutrophils in response to thrombin-activated platelets was also inhibited by the two polyphenols as was neutrophil migration toward thrombin-induced supernatants of platelets. Quercetin and resveratrol restored the decreased CD39/ATPdase activity in human umbilical vein endothelial cells, in response to thrombin as demonstrated by adenosine monophosphate (AMP) and adenosine increases in endothelial culture supernatants. Both polyphenols inhibited thrombin-induced MAPK, JNK and focal adhesion kinase activities in endothelial cells. Conclusion Quercetin and resveratrol interfere with the proinflammatory signaling of thrombin resulting in the inhibition of adenosine nucleotide secretion from activated platelets and decreased neutrophil function. Moreover, the polyphenols protect endothelial adenosine nucleotide metabolism when downregulated by thrombin. These observations may explain cardioprotective effects of grape products.

Cholesteryl ester transfer protein (CETP) greatly affects the metabolism of all lipoprotein classes including low-density lipoprotein (LDL) and high-density lipoprotein (HDL), both known to constitute powerful risk factors for coronary artery disease (CAD). We now report the successful first cloning and characterization of single-chain antibody fragments specific for CETP. A recombinant phage display library was generated using spleen mRNA isolated from BALB/c mice that had been immunized with highly purified CETP. Screening of the library yielded two single-chain antibody fragments with high affinity for CETP, termed 1CL8 and 1CL10, displaying respective K D values of 4.36 × 10 -9 M and 4.64 × 10 -9 M as determined by affinity sensor technology. Amino acid sequence comparison indicated the complementarity-determining regions of the respective heavy chains to be responsible for CETP high affinity binding. Fragment 1CL8 was successfully employed in clinical chemical quantification systems that uncovered an association in humans between plasma CETP concentration and total body fat mass (r=0.50, p

Transport of triglycerides (TGs) and cholesteryl esters (CEs) in plasma can be viewed as taking place via two major groups of lipoproteins, the TG-rich lipoproteins (chylomicrons and VLDL), on one hand, and the cholesterol-rich lipoproteins (LDL and HDL), on the other. The metabolism of these groups is linked by exchange processes, catalyzed mainly by a plasma glycoprotein referred to as lipid transfer protein I (LTP-I) (1) or cholesteryl ester transfer protein (CETP) (2-5).

Obesity is frequently associated with type 2 diabetes. We previously observed an association of a functional G/A polymorphism in the uncoupling protein 2 (UCP2) promoter with obesity. The wild-type G allele was associated with reduced adipose tissue mRNA expression in vivo, reduced transcriptional activity in vitro, and increased risk of obesity. On the other hand, studies in animal and cell culture models identified pancreatic β-cell UCP2 expression as a main determinant of the insulin secretory response to glucose. We therefore ascertained associations of the −866G/A polymorphism with β-cell function and diabetes risk in obesity. We show here that the pancreatic transcription factor PAX6 preferentially binds to and more effectively trans activates the variant than the wild-type UCP2 promoter allele in the β-cell line INS1-E. By studying 39 obese nondiabetic humans, we observed genotype differences in β-cell function; wild-type subjects displayed a greater disposition index (the product of insulin sensitivity and acute insulin response to glucose) than subjects with the variant allele (P < 0.03). By comparing obese subjects with and without type 2 diabetes, we observed genotype-associated differences in diabetes prevalence that translated into a twofold age-adjusted risk reduction in wild-type subjects. Thus, the more common UCP2 promoter G allele, while being conducive for obesity, affords relative protection against type 2 diabetes.

Objective— Obesity is associated with increased morbidity and mortality from atherosclerotic disease. Lipid abnormalities contribute to the increased relative risk in obese subjects. Cholesteryl ester transfer protein (CETP) mass is increased in these patients and might mediate the atherogenic lipoprotein pattern observed in obesity. Methods and Results— Twenty-one morbidly obese, middle-aged, female subjects participated in this prospective study. Subjects were examined before and 1 year after surgical treatment. Fat mass was determined by body impedance analysis; CETP mass, by ELISA; CETP activity, by exogenous substrate assay; and LDL particle diameter, by gradient gel electrophoresis. Mean weight loss after 1 year was 28.7 kg; mean fat mass loss was 22.6 kg. Mean CETP mass decreased from 1.81 to 1.32 μg/mL ( P =0.008); mean CETP activity decreased from 244 to 184 nmol · mL −1 · h −1 ( P =0.004); and in parallel, the mean diameter of LDL particles increased (256.8 to 258.4 Å, P =0.04). Conclusions— We conclude that weight loss is associated with a pronounced decrease in CETP mass and activity and a consistent increase in LDL particle diameter. After 1 year of this prospective study in morbidly obese subjects undergoing weight loss by surgical treatment, it has been determined that some features of the atherogenic lipoprotein profile can be reversed.

Leptin is an adipocyte-derived protein, which signals the status of current energy stores and energy intake to the central nervous system. Interferon-alpha therapy is frequently associated with loss of appetite and weight reduction. In this study, we tested whether interferon-alpha is able to regulate leptin synthesis. We therefore determined leptin plasma concentrations in thirteen patients with chronic hepatitis C who were treated with 1 x 10(7) IU interferon-alpha daily, up to 21 days after initial treatment. Furthermore, leptin concentrations and messenger RNA levels were quantified in interferon-alpha-treated and untreated murine adipocytes. After reaching peak plasma levels at 12 hours, probably reflecting the circadian rhythm, leptin concentrations fell and were significantly lower after 14 days. They remained significantly decreased 17 and 21 days after the start of the interferon-alpha treatment. In murine adipocytes exposed to interferon-alpha, leptin secretion was significantly decreased while messenger RNA levels remained unchanged. Our data suggest that, in contrast to proinflammatory cytokines such as interleukin-1, interferon-alpha suppresses leptin secretion in adipose tissue. We therefore hypothesize that loss of weight and appetite in interferon-alpha-treated patients with chronic hepatitis C might not be due to an elevation of leptin resulting in signals of increased energy stores in the brain.

To study possible mechanisms for the suggested protective effect of hormone-replacement therapy (HRT) with respect to cardiovascular disease we investigated lipoprotein parameters, mass and activity of lipoprotein-metabolizing enzymes, magnitude of postprandial lipemia, and vascular endothelial function in 13 postmenopausal women. All patients were examined before and 3 months after implementation of HRT with estrogen alone (group A, n = 6) or estrogen plus gestagen (group B, n = 7). HRT (groups A and B) resulted in enhanced total transfer of cholesteryl ester (CE) from high-density lipoprotein (HDL) to apolipoprotein B (apoB)-containing lipoproteins (56% [plusmn] 11.45% v 50.82% [plusmn] 13.68%, P [lt ] .05) and increased apoA-I plasma concentration (171 [plusmn] 30 v 147 [plusmn] 22 mg/dL, P [lt ] .05). Fasting triglycerides (TG) were increased (134 [plusmn] 40 v 115 [plusmn] 39 mg/dL, P [lt ] .05). In group A patients the magnitude of postprandial lipemia increased significantly (1,737 [plusmn] 756 v 1,475 [plusmn] 930 mg TG/dL plasma/8 h, P [lt ] .05) without any change in lipoprotein lipase (LPL) activity, but with a concomitant decrease in low-density lipoprotein (LDL) size. In both groups flow-mediated dilation (FMD) reflecting vascular endothelial function was not influenced, suggesting that HRT may not directly affect vascular function but rather alters lipoprotein metabolism. The increase of apoA-I was not accompanied by an equivalent rise of HDL cholesterol. Based on the present data this finding can be readily explained by an increase in CE transfer from HDL to TG-rich lipoproteins, which is not due to increased cholesteryl ester transfer protein (CETP) plasma levels, but rather reflects an increase in fasting and postprandial TG. In conclusion, the net effect of accelerated CE transfer due to HRT depends on the balance of proatherogenic aspects, like the generation of small dense LDL, and antiatherogenic aspects, like the stimulation of reverse cholesterol transport.

Endothelial dysfunction is an early marker of atherosclerosis occurring in patients with type 2 diabetes mellitus. Endothelium-dependent dilation (EDD) has been shown to improve by combined therapy of insulin and metformin. Studies on endothelium-independent vasodilatory capacity, however, have had controversial results. We sought to investigate the vascular reactivity--EDD and endothelium-independent dilation--and their changes induced by the addition of insulin therapy to patients with type 2 diabetes mellitus pretreated with diet and oral hypoglycemic drugs. We therefore performed vascular studies in 21 poorly controlled type 2 diabetic patients and 11 nondiabetic control subjects by using high resolution ultrasound of the brachial artery. After 3 months of additional insulin therapy, vascular and laboratory measurements including C-reactive protein and parameters of glucose and lipoprotein metabolism were repeated. At baseline, EDD was significantly impaired in diabetic patients compared with controls (2.7 +/- 2.2% vs 7.0 +/- 1.8%, p

OBJECTIVESWe sought to analyze diameter changes of conduit arteries in response to whole-body exercise and hypothesized that this response might be endothelium-dependent and, therefore, impaired in smokers.BACKGROUNDHyperemia and coincident vasodilation are pivotal mechanisms for meeting the increased metabolic demands of active muscle tissue during physical exercise, but studies in humans are sparse.METHODSWe studied diameter and blood flow of the femoral and brachial arteries in response to a submaximal bicycle exercise test in 10 nonsmoking and 8 smoking healthy male subjects. During an exercise period of 40 min the investigated conduit arteries were periodically scanned in longitudinal sections by high-resolution ultrasound. In the same subjects flow-mediated dilation (FMD) of the brachial artery was recorded by inducing an ischemia through a forearm-occluding cuff.RESULTSIn response to exercise the diameter of the femoral artery significantly increased in both nonsmokers and smokers, with a diminished response in smokers (9.2 ± 1.9% vs. 4.8 ± 1.6%, p < 0.001). Flow-mediated dilation of the brachial artery induced by forearm occlusion was also reduced in smoking subjects, revealing a strong correlation between these different methods of FMD (exercise vs. forearm ischemia) (r = 0.88, p < 0.001). In contrast, blood flow increase of the femoral artery was similar in nonsmoking and smoking subjects (392 ± 77% vs. 382 ± 109%, p = NS).CONCLUSIONSConduit arteries react with a flow-mediated dilation in response to whole-body exercise. The impairment of this vasodilation observed in smokers was strongly related to a decrease of endothelium-dependent dilation induced by forearm ischemia, indicating that endothelial dysfunction represents the underlying mechanism.

Phospholipid transfer protein plays a key role in lipoprotein metabolism by catalysing the transfer of phospholipids from triglyceride-rich lipoproteins to high-density lipoproteins and, also, within the high-density lipoprotein family, from particle to particle. This transfer results in a change of HDL particle size and the generation of pre-beta-high-density lipoproteins which function as initial lipid acceptors in the process of reverse cholesterol transport. Because adipose tissue is a source of phospholipid transfer protein we investigated the influence of obesity and insulin sensitivity on phospholipid transfer protein activity.Using an exogenous substrate assay phospholipid transfer protein activity was measured in plasma specimens of 190 normolipidaemic, non-diabetic subjects with BMI ranging from 19 to 43 kg/m2. Insulin sensitivity was measured by the short insulin tolerance test.Phospholipid transfer protein activity was associated with BMI (r = 0.46, p0.01), body fat mass (r = 0.39, p0.01), subcutaneous fat area (r = 0.32, p0.01) and plasma leptin concentration (r = 0.24, p0.01) but not with insulin sensitivity expressed as the k(s) of the insulin tolerance test (kITT value) (r = -0.14, p = 0.40). Accordingly, phospholipid transfer protein activity was higher in obese than in nonobese subjects. As determined by linear regression analysis, BMI was the sole predictor of phospholipid transfer protein activity in plasma explaining 22.2% of the activity (p0.01).This data suggests that increased phospholipid transfer protein activity in obese subjects is a consequence of obesity itself without the contribution of insulin resistance and can be explained by increased synthesis of phospholipid transfer protein from the enlarged mass of adipose tissue.

Self-administration of anabolic-androgenic steroids to increase muscular strength and lean body mass has been used widely among athletes. Flow mediated dilatation (FMD) determined by ultrasound of the brachial artery is accepted as both an in vivo index of endothelial function and an indicator for future atherosclerosis. FMD was calculated in 20 male non-smoking body builders in different phases of their training cycle and in six male non-smoking control athletes. Ultrasound studies of the brachial artery were performed according to the protocol of Celermajer et al. Of the entire training cycle, work-out phase was training phase without actual intake of anabolic-androgenic steroids over 8 weeks; build-up phase included actual intake of anabolic-androgenic steroids; and competition phase consisted of 8 weeks post intake of anabolic-androgenic steroids. Baseline characteristics did not differ between body builder groups except for a higher weight in competition phase body builders. Hormonal analysis revealed suppressed luteinizing hormone and follicle stimulating hormone levels in build-up phase body builders. The lipid profiles showed a marked reduction of HDL-C in build-up phase body builders. FMD was reduced in body builders of all phases when compared to control athletes (work-out phase: 2.5+/-2.7%; build-up phase: 2.1+/-3.0%; competition phase: 0.4+/-2.9% vs. 10.9+/-4.4%, P0.05 by pairwise comparison using Scheffe's test for work-out phase, build-up phase and competition phase vs. control athletes). The glyceryl trinitrate-induced vasodilatation was diminished, though not statistically significantly, in body builders when compared with control athletes. The differences in FMD persisted after adjustment for vessel size. Our data indicate that intake of anabolic-androgenic steroids is associated with both an atherogenic blood lipid profile and endothelial dysfunction and thus may pose an increased risk of atherosclerosis.

Obesity is the most common nutritional disorder in Western society. Uncoupling protein-2 (UCP2) is a recently identified member of the mitochondrial transporter superfamily that is expressed in many tissues, including adipose tissue. Like its close relatives UCP1 and UCP3, UCP2 uncouples proton entry in the mitochondrial matrix from ATP synthesis and is therefore a candidate gene for obesity. We show here that a common G/A polymorphism in the UCP2 promoter region is associated with enhanced adipose tissue mRNA expression in vivo and results in increased transcription of a reporter gene in the human adipocyte cell line PAZ-6. In analyzing 340 obese and 256 never-obese middle-aged subjects, we found a modest but significant reduction in obesity prevalence associated with the less-common allele. We confirmed this association in a population-based sample of 791 middle-aged subjects from the same geographic area. Despite its modest effect, but because of its high frequency (approximately 63%), the more-common risk allele conferred a relatively large population-attributable risk accounting for 15% of the obesity in the population studied.

Background: Hyperhomocysteinemia has been accepted as an independent risk factor for atherosclerosis and atherothrombosis. In recent years, several reports have appeared in the literature linking the use of anabolic steroids with acute vascular events in bodybuilders. In this study, we investigated whether hyperhomocysteinemia could contribute to the high vascular risk in bodybuilders taking anabolic steroids. Methods and results: Twenty-three bodybuilders in different phases of their training cycle and six control athletes participated in our study. Anthropomorphic measures displayed a higher body mass index for bodybuilders in the competition phase than for bodybuilders in the work-out and build-up phases, and for control athletes. Homocysteine levels were 8.7+/-1.6 µmol/l (mean+/-S.D.) in control athletes, 8.5+/-2.8 µmol/l in work-out phase bodybuilders, and 8.3+/-1.5 µmol/l in competition phase bodybuilders, but 11.9+/-3.1 µmol/l in build-up phase bodybuilders (P

A number of cross-sectional studies have demonstrated that the magnitude of postprandial lipemia or single postprandial triglyceride values predict asymptomatic and symptomatic atherosclerosis, independent of risk factors measured in the fasting state. Postprandial lipemia reflects an integrated measure of an individual's triglyceride metabolic capacity. Numerous genetic and environmental factors that are known or suspected to affect triglyceride transport contribute to the magnitude of postprandial lipemia. In this article, mechanisms linking postprandial lipemia with the development and progression of atherosclerosis are described, and determinants of the extent and duration of postprandial lipemia are discussed.

BACKGROUND Whether systemic inflammation is an epiphenomenon of atherosclerosis or whether it is part of the atherosclerosis causal pathway requires further study. DESIGN As part of a prospective population survey on the course and aetiology of atherosclerosis, we investigated the effects of plasma on the endothelial monolayers inducing activation for leukocyte transmigration. METHODS An age- and sex-stratified random sample of inhabitants of Bruneck (Italy) with and without atherosclerotic disease aged 50-69 years was selected. Carotid arteries were evaluated by duplex sonography at baseline (1990). Carotid arteries were re-evaluated for the development of new plaques 5 years later (1995). Frozen plasma samples from baseline were available for a random sample of 152 men. Monolayers of endothelial cells cultured in micropore filter insets were pre-treated with plasma, then normal human neutrophils were added to the endothelial cells and subsequent transmigration through the monolayers and micropore filters was measured. RESULTS The endothelial monolayers were activated for transmigration of leukocytes more potently by plasma from participants with carotid artery plaques than participants without it. Increased endothelial activation with plasma at baseline was associated with the development of new atherosclerotic lesions during a period of 5 years. CONCLUSIONS Plasma from individuals with prevalent atherosclerosis of the carotid arteries activates the endothelium for leukocyte transmigration, suggesting the presence of systemic pro-inflammatory mediators. In an epidemiological survey, follow-up data on new lesion formation after 5 years indicated that plasma-mediated endothelium activation for interaction with leukocytes precedes the development of atherosclerotic lesions.

Hyperdynamic circulation in liver cirrhosis: no evidence for peripheral vasodilation detected by ultrasound of the brachial artery

To evaluate the independent effect of cholesteryl ester transfer protein (CETP) on HDL concentrations in humans, we measured lipids, lipoproteins, postprandial lipemia after an oral fat load, CETP mass, and the activities of CETP, lipoprotein lipase (LPL), and hepatic lipase in 16 healthy, normotriglyceridemic men and in 23 men with moderate, primary hypertriglyceridemia on an American Heart Association Step I diet. Fasting triglycerides and postprandial lipemia were increased and HDL cholesterol (HDL-C) was decreased in hypertriglyceridemic men compared with control subjects ( P P P r =−.504, P =.014). Structural equation modeling of the association structures between HDL and fasting and postprandial triglycerides, endothelial lipases, and CETP in both groups indicated that the overall regression models for the two groups differed ( P P

Acute hepatitis C takes a chronic course in 50-80% of cases. Results with interferon treatment are conflicting. To evaluate the efficacy of high-dose interferon treatment, we initiated a pilot study in 1992 using 10 MU interferon-alpha2b administered subcutaneously daily until normalization of serum transaminase concentrations. Treatment was begun when a diagnosis of acute hepatitis C was established. HCV-RNA was tested using PCR prior to treatment, three times weekly during the first two weeks of treatment, and then once weekly until the end of therapy. During the 15-month follow-up, HCV-RNA tests were performed monthly up to month 6 and every two to three months thereafter. Twenty-four patients were enrolled at the time of writing; age ranged from 18 to 76 years (mean = 32), and nine patients were men. All patients presented with cholestatic hepatitis; 19 were actively abusing intravenous drugs, four had no known parenteral exposure, and one was a medical laboratory technician. All patients were anti-HCV positive, HCV-RNA positive, and HIV negative. Five patients were infected with genotype 3, five with genotype 1a, five with genotype 1b, three with genotypes 3 and 2, and one with genotypes 1 and 2. All patients exhibited normalized serum transaminase concentrations within 18-43 days; HCV-RNA became negative in all patients within 4-12 days. Toxicity did not exceed grade 1 and disappeared within three days of treatment. In the follow-up period, which ranged from six to 29 months (mean = 19.5 +/- 10.4), serum ALT concentrations remained normal and HCV-RNA remained negative in all patients except two dropouts and two patients who developed relapsing disease after having been HCV-RNA negative for three and eight months, respectively. In both patients, the same HCV genotype 3 reemerged. Serum ALT concentrations ranged from 531 to 1940 IU/liter (mean = 1055; normal22). Concentrations of HCV-RNA (Quantiplex; Chiron, Emeryville, California) were3.5 x 10(5) eq/ml in nine of 14 PCR-positive patients. In the other five patients, concentrations ranged from 10.4 x 10(5) eq/ml to 131.6 x 10(5) eq/ml (mean = 69.6 x 10(5)). No correlation was observed between HCV-RNA concentrations and serum ALT concentrations at presentation (r = 0.331; P = 0.67) and total dose of interferon-alpha2b administered until normalization of ALT (r = -0.088; P = 0.74). Twenty-two of 24 patients completed treatment (two were noncompliant). Of these, 20 achieved a complete response (HCV-RNA negative for at least six months). Two of these patients relapsed, and 18 (90%) remained HCV-RNA negative for 18.65 (+/-9.7) months. These findings suggest that high-dose interferon-alpha2b is well tolerated and effective in preventing a chronic course of hepatitis C infection.

Summary Post-prandial lipaemia represents the state of absorption during which TG metabolic capacity is under challenge. Low TG metabolic capacity imparts the risk of development of atherosclerosis. TG-intolerance has been shown to be an independent risk factor for CAD and impaired TG metabolic capacity could underlie a common high risk lipoprotein constellation of low HDL cholesterol and small sized HDL and LDL. Magnitude and duration of post-prandial lipaemia determine how much cholesterol is diverted from LDL and HDL into TG-rich lipoproteins through which it causes atherosclerosis. Potential means of intervention are improvement of TG metabolic capacity by reducing obesity, prescription of aerobic exercise, reduction of oxidizability of post-prandial lipoproteins by antioxidants and TG-lowering drugs.

In 17 patients with primary mixed hyperlipidemia we studied levels and composition of lipoproteins in fasting plasma, lipoprotein-modifying enzymes, and postprandial lipoprotein metabolism after an oral fat-tolerance test supplemented with vitamin A before, and 12 weeks after treatment with etophylline clofibrate. With treatment, fasting plasma cholesterol, triglycerides, and the levels of very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), and low density lipoproteins (LDL) decreased significantly; high density lipoprotein (HDL) cholesterol increased significantly. Treatment caused also an increase in the protein content of IDL, a decrease in the triglyceride content of LDL, and an increase in the size of LDL as assessed by gradient gel electrophoresis. Concentrations of triglycerides, chylomicrons, and chylomicron remnants after an oral fat load supplemented with vitamin A decreased by 33%, 30% and 6%, respectively (P0.005; P0.01; and P0.05). The activity of lipoprotein lipase and hepatic lipase in postheparin plasma increased by 51% and 45%, respectively (P0.01; P0.05). We found a decrease in the mass concentration of cholesteryl ester transfer protein (P0.05). Stepwise multiple regression analysis showed that the triglyceride content of LDL is determined primarily by fasting triglycerides (r = + 0.53, P0.05;baseline) and cholesteryl ester transfer protein (r = + 0.49, P0.05; 12 weeks); in contrast, the triglyceride content of HDL3 is determined exclusively by accumulation of postprandial triglycerides (r = + 0.67; P0.05; baseline) and postprandial chylomicrons (r = +0.87; P0.005; 12 weeks). We conclude that hypolipidemic treatment with etophylline clofibrate favorably affects the cardiovascular risk factor profile in primary mixed hyperlipidemia.

We report on a female patient with hereditary hemorrhagic teleangiectasia complicated by subacute thrombosis of the superior mesenteric vein. Despite gastrointestinal bleeding, anticoagulation therapy with heparin had to be performed to prevent bowel infarction. In this case, local vascular lesions with altered blood flow in combination with hyperfibrinogenemia might have caused superior mesenteric vein thrombosis.

Pancreas transplantation with systemic venous drainage of the graft causes elevated plasma levels of insulin, known to be a potent regulator of plasma lipoprotein metabolism. We studied 11 post-type I diabetic pancreas-kidney transplant recipients, 9 type I diabetic kidney transplant recipients displaying peripheral hyperinsulinemia due to subcutaneous insulin treatment, 11 nondiabetic kidney transplant recipients as controls for the effects of immunosuppressive medication, and 11 healthy control subjects, all matched for age, sex, and body mass index. We determined fasting lipids, lipoproteins and lipolytic enzymes, as well as postprandial lipid metabolism after a standardized oral fat load. High-density lipoprotein (HDL) cholesterol averaged 1.98 (0.40) mmol/L in pancreas-kidney transplant patients, clearly higher than that of kidney transplant recipients (1.52 (0.36) mmol/L, P < 0.05) or of controls (1.50 (0.38) mmol/L, P < 0.05). In pancreas-kidney transplant patients postprandial lipemia was lowest and lipoprotein lipase activity was highest (average 32% and 154%, respectively, of the mean of the controls) compared with nondiabetic kidney transplant recipients (P < 0.005, P < 0.05) and healthy controls (P < 0.001, P < 0.01). In type I diabetic kidney transplant recipients the levels of HDL cholesterol (1.88 (0.63) mmol/L), postprandial lipemia, and lipoprotein lipase activity were intermediate between pancreas-kidney transplant patients and healthy controls. The distinctly elevated HDL cholesterol in pancreas-kidney transplant patients can be readily explained by the low postprandial triglyceride levels resulting from a high activity of lipoprotein lipase. The very favorable lipid profile in post-diabetic pancreas-kidney transplant recipients could be expected to counteract the severe atherosclerotic risk of long-standing diabetes.

A recently developed immunosuppressive substance, 2-chloro-2-deoxyadenosine (2-CdA), was reported to inhibit monocyte functions at low concentration. Because macrophages play a key role in the formation of atherosclerotic plaques, it was of interest to study the effect of 2-CdA on cellular lipid metabolism. For this purpose we have used a macrophage cell line (P388) to perform incubation studies in the presence of acetylated low density lipoprotein (Ac-LDL) and 2-CdA. The addition of 2-CdA, in concentrations ranging from 5–20 nM, induced a dose-dependent decrease in cellular cholesterol content and in the amount of extracellular [14C]oleic acid (OA) incorporated into the cholesteryl ester (CE) fraction. The effect was maximized at 20 nM 2-CdA with an 86% reduction in cholesterol esterification compared to controls (P

In 16 members of two Austrian families affected by a missense mutation at codon 188 of the lipoprotein lipase (LPL) gene (8 heterozygous and 8 normal subjects), carrier status for the mutation as determined by DNA analysis was related to LPL activity in postheparin plasma, to the magnitude of postprandial lipemia, and to concentration, composition, and size of the major lipoprotein classes of postabsorptive plasma. Carriers exhibited clearly reduced LPL activity, normal fasting triglycerides, but pronounced postprandial lipemia. The carriers' impaired triglyceride tolerance, as evident in the postprandial state of challenge only, was associated with a fasting lipoprotein constellation characterized by (a) enrichment of HDL2 with triglycerides, (b) reduced HDL2-cholesterol, (c) enrichment of VLDL and intermediate density lipoprotein (IDL) with cholesteryl esters, (d) elevated IDL levels, and (e) small-sized LDL. Within any given individual, the degrees of expression of these characteristics were quantitatively and continuously related with each other as well as with the magnitude of lipemia and with LPL activity.

An inverse relation between high-density lipoprotein (HDL) cholesterol and the incidence and/or prevalence of coronary heart disease (CHD) has been firmly established in numerous epidemiologic studies. Data from the Framingham Heart Study, the Lipid Research Clinics (LRC) Prevalence Mortality Follow-up Study, the LRC Coronary Primary Prevention Trial, and the Multiple Risk Factor Intervention Trial have all suggested a 2% to 3% decrease in CHD risk for each 1 mg/dl (0.026 mmol/L) increase in HDL cholesterol after correction for other risk factors [1]. In man, limited information is available as to whether increasing HDL cholesterol would reduce the risk of CHD. However, animal experiments support the notion that increasing HDL may be beneficial. Infusion of HDL into rabbits fed an atherogenic diet was associated with reduced severity and extent of atherosclerotic lesions in comparison with control animals fed the same diet [2]. Similar conclusions were reached in transgenic mice in that overexpression of human apolipoprotein (apo) A-I decreased the severity of diet-induced atherosclerosis [3].

There exists an interrelationship between high density lipoprotein (HDL)-cholesterol, the plasma levels of triglyceride (TG)-rich lipoproteins, and the risk of coronary artery disease (CAD). The levels of HDL-cholesterol and CAD risk show a strong negative association, triglycerides and CAD risk show weaker relation, and HDL and TG-rich lipoproteins show strong inverse association. The purpose of this article is to consider together HDL-cholesterol, triglycerides, and CAD risk.

Postprandial hypertriglyceridemia which puts a stressful challenge to triglyceride transport, is likely to increase the risk of cardiovascular disease because it provides the opportunity for cholesteryl esters to be transferred from LDL and HDL into triglyceride-rich particles conferring on them atherogenic potential. Increased shunting of cholesteryl esters into triglyceride-rich lipoproteins appears to be related to impaired triglyceride metabolic capacity which is indicated by the fasting lipoprotein constellation most frequently associated with coronary artery disease: low HDL cholesterol and a preponderance of small-sized HDL and LDL.

Oral glucose tolerance testing (OGTT) and quantification of serum fructosamine levels were performed in 190 asymptomatic women in weeks 24-28 of pregnancy. OGTT identified 10 of the 190 women as having gestational diabetes, but serum fructosamine quantification failed to do so because none of these 10 women exhibited levels exceeding the normal limit of 2.76 mmol/l. The mean fructosamine level in this group was 1.72 +/- 0.25 mmol/l compared to 1.60 +/- 0.15 mmol/l in the other 180 women without gestational diabetes. Fructosamine was found to correlate only with postload glucose values in excess of 180 mg/dl at 2 h (r = 0.87; p = 0.01), i.e. with the highest overall glucose values, but not with fasting glucose or milder postprandial hyperglycemia of under 180 mg/dl. We conclude that quantification of fructosamine detects only the rather severe cases of gestational hyperglycemia, but is too insensitive to uncover mild asymptomatic gestational diabetes mellitus, and we do not consider fructosamine to be a useful parameter for the diagnosis of this condition.

Obesity is associated with lipid abnormalities leading to an increased morbidity and mortality from atherosclerotic disease. Lipid transfer proteins such as Cholesteryl Ester Transfer Protein (CETP) and Phospholipid Transfer Protein (PLTP), and lipases such as lipoprotein lipase (LPL) and hepatic lipase (HL) are involved in the pathogenesis of the obesity associated proatherogenic dyslipidemia. Nineteen severely obese female subjects undergoing laparosopic gastric banding participated in this prospective study. Subjects were examined with respect to body composition, lipid profile, CETP, PLTP, LPL and HL before and 1 year after surgical treatment. Mean weight loss was 22.2 kg, mainly due to losses in the fat depots. Triglycerides decreased and HDL(2)-C increased significantly. In respect to transfer proteins mean CETP mass decreased from 1.82 to 1.71 microg mL(-1) (P = 0.043) and mean PLTP activity was reduced from 7.15 to 6.12 micromol mL(-1) h(-1) (P = 0.002), in parallel. In addition, both mean LPL activity and mean HL activity tended to decrease from 297 to 248 nmol mL(-1) h(-1) for LPL (P = 0.139) and from 371 to 319 nmol mL(-1) h(-1) for HL (P = 0.170), respectively. We conclude that weight loss induced by bariatric surgery is associated with the amelioration of the obesity-associated dyslipidemic state. This improvement may be attributable to decreased mass and action of the adipocyte tissue derived lipid transfer proteins CETP and PLTP.

To determine the molecular basis for type I hyperlipoproteinemia in two Austrian families, the lipoprotein lipase (LPL) gene of two patients exhibiting LPL deficiency was analyzed by Southern blotting and by direct genomic sequencing of DNA amplified by polymerase chain reaction (PCR). All exons of the LPL gene except part of the noncoding region of exon 10, all splice donor and acceptor sites, as well as 430 basepairs of the 5′-region including the promotor were sequenced. A homozygous substitution of adenine for guanine in the fifth exon at cDNA position 818 of the LPL gene was found in both patients. Our sequencing strategy largely ruled out a linkage disequilibrium of the identified nucleotide change with another defect potentially causing the clinical phenotype. The base change described abolishes a normally present AvaII restriction site allowing the identification of carriers of the mutant allele by AvaII digestion of PCR fragments of exon 5; three members of the two families were homozygous for this mutation and ten members were heterozygous. The activity of LPL in postheparin plasma was almost completely absent in homozygotes and about half normal in heterozygotes. The loss of activity was related to LPL protein structure. This mutation alters the amino acid sequence at residue 188 from Gly to Glu. The conformational preferences of the protein chain around position 188 were calculated with the use of a knowledge-based computerized method. The most probable conformation is a beta-turn formed by residues 189–192. The mutation seems to destabilize the beta-turn and/or a yet larger domain critical for substrate alignment.