De chemie van xanthomen en xanthelasmata is enkele decennia geleden onderzocht. Daarbij is gebleken dat het om ophoping van cholesterol en fosfolipiden in macrofagen gaat. De lichtgele kleur wordt geleverd door in vet oplosbare gele kleurstoffen, zoals caroteen. Het triglyceridengehalte is laag, mogelijk omdat triglyceriden in macrofagen kunnen worden gemetaboliseerd.

Men moet onderscheid maken tussen de verschillende vormen van hypercholesterolemie enerzijds en de effecten van voeding, inclusief toevoegingen aan de voeding en medicamenten anderzijds.

Fibraten veroorzaken 20-40% daling van het triglyceride(TG)-gehalte en 10-20% stijging van het HDL-cholesterolgehalte (HDL-chol), maar slechts een matige (10-20%) daling van het LDL-cholesterolgehalte.

Objective. Metformin has been associated with the serious side-effect lactic acidosis. However, it remains unclear whether the use of metformin was a cause or a coincidence in lactic acidosis.Design. A literature search of the Index Medicus (1959-66) and of the databases Embase, Medline, Medline Express (1966-99) was performed using the keywords metformin, biguanides and lactic acidosis. All articles of cases with metformin-induced lactic acidosis (MILA) were cross-referenced.Subjects. Cases were included for analysis if they met the following criteria: serum pH less than or equal to7.35, lactate concentration greater than or equal to5 mmol L-1.Intervention. A forum of six experts in intensive care medicine independently categorized the cases in MILA unlikely (score 0), possible MILA (score 1) or probable MILA (score 2).Main outcome measures. Statistical analysis included the paired interobserver agreement (kappa) and multivariate regression analysis.Results. Of 80 reported cases, 33 were excluded because of insufficient quality. The forum scores of the remaining 47 cases were distributed normally with a mean score of 7 (range 2-10). The kappa-value was 0.041 (SD = 0.24, range -0.514, 0.427). Neither lactate concentration nor mortality correlated with serum metformin concentrations.Conclusions. Given the low interobserver agreement and the lack of any relationship between metformin levels and outcome parameters, the concept that there is a simple, causal relationship between metformin use and lactic acidosis in diabetic patients has to be reconsidered.

Cardiomyopathy is a major cause of death in overt acromegaly. Recent progress in research has increasingly revealed the molecular mechanisms concerning growth hormone and insulin-like growth factor in the development of heart failure. In this article, we propose mechanisms according to which heart failure occurs, and we aim to extrapolate this knowledge to more general processes involved in heart failure.

Familial combined hyperlipidemia (FCHL) patients have an impaired catabolism of postprandial triglyceride (TG)-rich lipoproteins (TRLs). We investigated whether atorvastatin corrects the delayed clearance of large TRLs in FCHL by evaluating the acute clearance of Intralipid (10%) and TRLs after oral fat-loading tests. Sixteen matched controls were included. Atorvastatin reduced fasting plasma TG (from 3.6 +/- 0.4 to 2.5 +/- 0.3 mM; mean +/- SEM) without major effects on fasting apolipoprotein B48 (apoB48) and apoB100 in large TRLs. Atorvastatin significantly reduced fasting intermediate density lipoprotein (Svedberg flotation, 12-20)-apoB100 concentrations. After Intralipid, TG in plasma and TRL showed similar kinetics in FCHL before and after atorvastatin treatment, although compared with controls, the clearance of large TRLs was only significantly slower in untreated FCHL, suggesting an improvement by atorvastatin. Investigated with oral fat-loading tests, the clearance of very low density lipoprotein (Sf20-60)-apoB100 improved by 24%, without major changes in the other fractions. The most striking effects of atorvastatin on postprandial lipemia in FCHL were on hepatic TRL, without major improvements on intestinal TRLs. Fasting plasma TG should be reduced more aggressively in FCHL to overcome the lipolytic disturbance causing delayed clearance of postprandial TRLs.

The role of endogenous estrogens and androgens and their potential interaction in atherosclerosis is not well understood. Therefore, we investigated the effects of natural menopause and endogenous sex steroids on triglycerides (TG), a major risk factor for cardiovascular disease in women. Fasting lipid and lipoprotein concentrations, postheparin lipase activities, kinetic indicators of triglyceride lipolysis, and various hormone levels, including dehydroepiandrostenedione-sulfate (DHEA-S), (bioavailable) testosterone, and androstenedione, were determined in 18 premenopausal and 18 postmenopausal women, matched for age and body composition. Fasting plasma TG were 0.69 +/- 0.29 mmol/L in postmenopausal women and 0.73 +/- 0.33 mmol/L in premenopausal women (difference not significant [NS]). Approximately 30% of all plasma TG were present in the very-low-density lipoproteins (VLDLs) in both groups. No differences were found between groups in plasma lipolytic potential of TG-rich lipoproteins. Univariate analysis revealed that VLDL-TG concentrations were strongly related to insulin (r = 0.84, P =.0001) and androstenedione (r = 0.65, P =.004) in postmenopausal women. Multivariate analysis of potential determinants of VLDL-TG showed that insulin, androstenedione, and bioavailable testosterone were independent variables, explaining 87% of the variability (r = 0.93, P =.0001) in postmenopausal women. In contrast, in premenopausal women, the only identified predictor of fasting VLDL-TG in univariate and multivariate analysis was insulin (r = 0.72, P =.001). Our results show that the association of androgens with TG varied depending on androgen concentrations, the relative androgenic potential, and most importantly on hormonal milieu. Endogenous androgens were only related to plasma VLDL-TG in the estrogen-deficient state.

Objective— An increased hepatic flow of free fatty acids (FFAs) is associated with impaired peripheral FFA trapping by malfunctioning of the complement component 3 (C3)/acylation-stimulating protein system and overproduction of VLDL in familial combined hyperlipidemia (FCHL). Postprandial ketone bodies reflect FFA oxidation in the liver, but the postprandial changes in male and female patients separately have not been determined yet. Gender differences in postprandial ketone bodies and C3 changes were investigated in normolipidemic patients and patients with untreated FCHL. Methods and Results— Thirty-two normolipidemic patients (16 female and 16 male) and 19 patients with untreated normolipidemia (9 female and 10 male) underwent an oral fat-loading test. Total and incremental areas under the curves (AUC and dAUC, respectively) after the oral fat load were calculated. Triglyceride AUC was similar between genders in each group. Normolipidemic female subjects showed a higher levels of dAUC-hydroxybutyric acid than male subjects (1.37±0.49 and 0.98±0.43 mmol · h/L). In FCHL, a similar trend was observed in female (1.92±0.38) compared with male (1.55±0.87) subjects. In contrast to normolipidemia, FCHL did not show a postprandial increase in C3, although C3 was higher in FCHL. Conclusions— Women have higher postprandial ketone bodies than men, probably reflecting enhanced postprandial hepatic FFA oxidation. In FCHL, both genders have higher postprandial ketone bodies and therefore higher hepatic FFA delivery. The higher fasting and postprandial C3 levels in FCHL may reflect resistance of the C3/acylation-stimulating protein system to promote peripheral fatty acid trapping.

Increased cardiovascular mortality due to premature atherosclerosis is a clinical feature in the adult-onset GH deficiency (AGHD) syndrome. Inflammation is a key feature in atherogenesis and may be triggered by postprandial lipoprotein remnants. We hypothesized that increased postprandial lipoprotein remnant levels in AGHD may be associated with an inflammatory response. In this case-control study, 10 AGHD patients [6 males and 4 females; age, 48 +/- 9 yr; body mass index (BMI), 26.9 +/- 2.6 kg/m(2)] and 10 healthy control subjects (matched for age, BMI, gender, baseline lipid levels, and apolipoprotein E genotype) were included. They all ingested an oral fat load. Fasting and postprandial levels of plasma remnant-like particle-cholesterol (RLP-C; 0.31 +/- 0.13 mmol/liter and 4.14 +/- 1.37 mmol/liter.h in GHD; 0.18 +/- 0.06 mmol/liter and 2.56 +/- 1.02 mmol/liter.h in controls, respectively) were significantly increased in AGHD patients compared with control subjects. The median inflammatory cytokines, IL-6 and TNF-alpha, were higher in the fasting [3.9 (range, 3.1-11.9) pg/ml and 6.8 (range, 2.5-27.6) pg/ml, respectively] and postprandial [151.7 (range, 87.0-294.3) pg/ml.24 h and 289.9 (range, 87.5-617.6) pg/ml.24 h, respectively] states in AGHD than in controls [fasting, 0.9 (range, 0.2-5.2) pg/ml and 2.8 (range, 2.5-5.7) pg/ml; and postprandial, 54.5 (range, 11.50-126.5) pg/ml.24 h and 118.3 (range, 81.2-243.1) pg/ml.24 h, respectively]. In addition, postprandial profile of RLP-C and IL-6 in AGHD and in the total group were significantly associated (r(2) = 0.44, P < 0.05; and r(2) = 0.38, P < 0.01, respectively). In conclusion, the increased postprandial RLP-C level in GHD is associated with an inflammatory response that may result in increased susceptibility for premature atherosclerosis.

Postprandial hypertriglyceridemia associated with insulin resistance is one of the cardiovascular risk factors in obesity and type 2 diabetes. It is not known whether diabetics have a more pronounced postprandial hypertriglyceridemia than obese subjects. Daylong triglyceridemia, representing postprandial lipemia, was determined in obese subjects with and without type 2 diabetes and in lean subjects. Nineteen type 2 diabetics (F/M: 7/12, body mass index [BMI]: 30.6 +/- 5.4 kg/m(2)), 45 obese nondiabetics (F/M: 16/29, BMI: 29.5 +/- 2.6 kg/m(2)) and 78 lean subjects (F/M: 28/50, BMI: 23.7 +/- 2.2 kg/m(2)) measured capillary triglycerides (TGc) during 3 days on 6 fixed time-points each day in an out-of-hospital situation. Daylong TGc profiles were calculated as mean integrated area under the TGc-curve (TGc-AUC). Fasting plasma TG were higher in diabetics and obese nondiabetics (1.81 +/- 0.79 and 1.77 +/- 0.80 mmol/L) compared with lean subjects (1.23 +/- 0.67 mmol/L, P <.001). TGc-AUC was similarly increased in both diabetics and obese nondiabetics (35.0 +/- 12.1 and 35.2 +/- 10.6 mmol.1 h/L) compared with lean controls (25.5 +/- 12.0 mmol.1 h/L, P <.001). Self-reported energy intake was not significantly different between the groups. Fasting TGc (r =.87, P <.001) and waist circumference (r =.51, P <.001) were the parameters best associated with TGc-AUC. Using stepwise multiple regression analysis, fasting TGc, BMI, total cholesterol, and high-density lipoprotein (HDL) cholesterol were the best predictors of TGc-AUC, explaining 77% of the variation. The cut-off level for "normal" TGc-AUC, calculated as the 75th percentile of TGc-AUC in lean subjects, was 30.7 mmol.1 h/L and corresponded with a fasting TGc of 1.8 mmol/L (eg, 1.6 mmol/L in plasma), calculated using univariate regression analysis. In conclusion, daylong triglyceridemia is similarly increased in diabetics and obese nondiabetics compared with lean subjects. Fasting TG and central obesity largely determine daylong triglyceridemia, independent of the presence of type 2 diabetes. Decreasing fasting plasma TG below 1.6 mmol/L could lead to a normalization of postprandial lipemia in obese subjects with and without diabetes.

Postprandial hyperlipidemia is associated with premature coronary sclerosis in fasting normolipidemic subjects. Self-determined daytime capillary triglyceride (cTG) profiles were compared between 26 fasting normotriglyceridemic patients with premature coronary artery disease (CAD) and 26 controls matched for gender, age and BMI. Daytime triglyceridemia was calculated as total area under the cTG-curve (cTG-AUC). Total and LDL cholesterol were not different between CAD patients (5.4+/-0.8 mmol/l and 3.6+/-0.7 mmol/l, respectively) and controls (5.0+/-0.9 mmol/l and 3.3+/-0.8 mmol/l, respectively). Patients with CAD were characterized by a 44% higher cTG-AUC than matched controls (P<0.01). Using logistic regression analysis, cTG-AUC was the strongest predictor of the presence of CAD (P<0.001). Adding apo AI to the model improved the predictive power from 71 to 77%. Sixteen patients were studied after increasing doses of simvastatin up to 80 mg/day. Although the target for LDL cholesterol was reached by simvastatin 20mg/day, significant effects on cTG-AUC were found only by higher doses of simvastatin. Simvastatin 40 mg/day decreased cTG-AUC by 28% (P<0.05 versus baseline), reaching comparable values as in controls, without further improvement with simvastatin 80 mg/day (26% reduction versus baseline; P<0.05). Daytime triglyceridemia is linked to premature coronary sclerosis in fasting normotriglyceridemic patients. A higher dose of simvastatin was needed to normalize daytime triglyceridemia than was required to "normalize" LDL cholesterol.

UNLABELLED:GROWTH HORMONE AND ATHEROSCLEROSIS: Adult-onset growth hormone (GH) deficiency is associated with an increase in cardiovascular morbidity and mortality.MECHANISMS:Other than classical risk factors, such as dyslipidemia, a direct interaction between the activity of the GH/IGF-1 axis and the endothelium also plays a part. It is possible that the modulating effect of IGF-1 on nitric oxide (NO) synthesis is also important, together with the anabolic effect on the myocardiocytes. Substitution of recombinant GH induces rapid reduction in the atherosclerotic plaques, suggesting a direct effect of the GH/IGF axis on the atherosclerotic process. In addition to the acquired GH deficiency, as in non-substituted patients following hypophysectomy, attention has recently been focused on the relative GH deficiency as is seen in obesity and in the course of ageing. PERSPECTIVES FOR CARDIOVASCULAR ENDOCRINOLOGY: Therapeutic intervention in the GH/IGF axis might influence the atherosclerotic process. Study of the GH/IGF axis activity and of its correlation with atherosclerosis opens new perspectives in the understanding of the role of this axis in cardiovascular diseases.

OBJECTIVE:The cholesteryl ester transfer protein (CETP) plays a key role in the remodeling of triglyceride (TG)-rich and HDL particles. Sequence variations in the CETP gene may interfere with the effect of lipid-lowering treatment in type 2 diabetes.RESEARCH DESIGN AND METHODS:We performed a 30-week randomized double-blind placebo-controlled trial with atorvastatin 10 mg (A10) and 80 mg (A80) in 217 unrelated patients with diabetes.RESULTS:CETP TaqIB and A-629C polymorphisms were tightly concordant (P < 0.001). At baseline, B1B1 carriers had lower plasma HDL cholesterol (0.99 +/- 0.2 vs. 1.11 +/- 0.2 mmol/l, P < 0.05), higher CETP mass (2.62 +/- 0.8 vs. 2.05 +/- 0.4 mg/l, P < 0.001), and slightly increased, though not significant, plasma TGs (2.7 +/- 1.05 vs. 2.47 +/- 0.86, P = 0.34) compared with B2B2 carriers. Atorvastatin treatment significantly reduced CETP mass dose-dependently by 18% (A10) and 29% (A80; both vs. placebo P < 0.001, A10-A80 P < 0.001). CETP mass and activity were strongly correlated (r = 0.854, P < 0.0001). CETP TaqIB polymorphism appeared to modify the effect of atorvastatin on HDL cholesterol elevation (B1B1 7.2%, B1B2 6.1%, B2B2 0.5%; P < 0.05), TG reduction (B1B1 39.7%, B1B2 38.4%, B2B2 18.4%; P = 0.08), and CETP mass reduction (B1B1 32.1%, B1B2 29.6%, B2B2 21.9%; P = 0.27, NS). Similar results were obtained for the A-629C polymorphism.CONCLUSIONS:In conclusion, the B1B1/CC carriers of the CETP polymorphisms have a more atherogenic lipid profile, including low HDL, and they respond better to statin therapy. These results favor the hypothesis that CETP polymorphisms modify the effect of statin treatment and may help to identify patients who will benefit most from statin therapy.

A complex relationship exists between disease of the cardiovascular system and a spectrum of neural and humoral factors. Recently, the modulating role of hormones, such as thyroid hormone (1–4), in the atherosclerotic process has been emphasized. However, several other hormones in addition to thyroid hormone may contribute to atherogenesis, thereby constituting a key element in the concept of cardiovascular endocrinology (5). Recently, evidence has been provided to suggest that disturbances of the pituitary GH axis and its mitogenic partners, including IGF-I and IGF-binding proteins (IGFBP), are critical actors in the initiation of the atherosclerotic process (6–8). Indeed, disturbances in the GH axis/IGF system appear to be intimately related to the perturbed postprandial lipoprotein metabolism that is typical of subjects presenting premature atherosclerosis (9, 10). Furthermore, a high baseline plasma GH concentration is associated with increased cardiovascular mortality (11, 12). These observations suggest a U-shaped relationship between disturbances in the GH axis/IGF system and increased cardiovascular morbidity and mortality. In the present review we explore the key pathways of lipid metabolism in adult-onset GH deficiency (AGHD) that may be involved in the initiation of atherosclerosis and that result in elevated cardiovascular risk.

Twickler, Marcel MD, PHD, PHD*; Cramer, Maarten-Jan MD, PHD†; van Dam, P. Sytze MD, PHD‡; de Vries, Wouter R. PHD§; Erkelens, D. Willem MD, PHD*; Koppeschaar, Hans P. F. MD, PHD‡ Author Information