Familial hypercholesterolemia (FH) is an autosomal-dominant inherited disease with a prevalence of one in 500 (heterozygous) to one in 1,000,000 (homozygous). Mutations of the low-density lipoprotein (LDL) receptor gene, the apolipoprotein B100 gene, or the PCSK9 gene may be responsible for the disease. The resulting LDL hypercholesterolemia results in premature atherosclerosis as early as childhood (homozygous FH) or in adulthood (heterozygous FH). Current treatment modalities include lifestyle modification, combination drug therapy (statin-based), and apheresis. Mipomersen is an antisense oligonucleotide which inhibits apolipoprotein B production independent of LDL receptor function and thus works in homozygous FH, heterozygous FH, and other forms of hypercholesterolemia. Mipomersen is given 200 mg/week subcutaneously. Phase III studies indicate that the LDL cholesterol concentration can be reduced by 25%–47%, lipoprotein(a) levels by 20%–40%, and triglyceride concentrations by approximately 10%. In general, mipomersen has no effect on high-density lipoprotein cholesterol concentrations. Although there is considerable interindividual variability, the observed lipid effects are largely independent of age, gender, concomitant statin therapy, and underlying dyslipoproteinemia. The most common side effects are injection site reactions (70%–100%), flu-like symptoms (29%–46%), and elevated transaminases associated with an increased liver fat content (6%–15%). Mipomersen may be an interesting addon drug in patients with heterozygous or homozygous FH not reaching treatment goals, either because baseline values are very high or because high-dose statins are not tolerated.
antisense oligonucleotide; statin intolerance; apolipoprotein B
The first aim was to critically evaluate the extent to which familial hypercholesterolaemia (FH) is underdiagnosed and undertreated. The second aim was to provide guidance for screening and treatment of FH, in order to prevent coronary heart disease (CHD).
Methods and results
Of the theoretical estimated prevalence of 1/500 for heterozygous FH, <1% are diagnosed in most countries. Recently, direct screening in a Northern European general population diagnosed approximately 1/200 with heterozygous FH. All reported studies document failure to achieve recommended LDL cholesterol targets in a large proportion of individuals with FH, and up to 13-fold increased risk of CHD. Based on prevalences between 1/500 and 1/200, between 14 and 34 million individuals worldwide have FH. We recommend that children, adults, and families should be screened for FH if a person or family member presents with FH, a plasma cholesterol level in an adult ≥8 mmol/L(≥310 mg/dL) or a child ≥6 mmol/L(≥230 mg/dL), premature CHD, tendon xanthomas, or sudden premature cardiac death. In FH, low-density lipoprotein cholesterol targets are <3.5 mmol/L(<135 mg/dL) for children, <2.5 mmol/L(<100 mg/dL) for adults, and <1.8 mmol/L(<70 mg/dL) for adults with known CHD or diabetes. In addition to lifestyle and dietary counselling, treatment priorities are (i) in children, statins, ezetimibe, and bile acid binding resins, and (ii) in adults, maximal potent statin dose, ezetimibe, and bile acid binding resins. Lipoprotein apheresis can be offered in homozygotes and in treatment-resistant heterozygotes with CHD.
Owing to severe underdiagnosis and undertreatment of FH, there is an urgent worldwide need for diagnostic screening together with early and aggressive treatment of this extremely high-risk condition.
Cholesterol; Low-density lipoprotein; Atherosclerosis; Coronary heart disease; Cardiovascular disease
Although statins reduce cardiovascular morbidity and mortality further risk reduction is needed. In this respect low HDL-cholesterol concentrations and/or elevated triglyceride concentrations may be potential treatment targets. Niacin (nicotinic acid) is an effective drug which increases the plasma concentration of high-density lipoprotein (HDL)-cholesterol and decreases the concentration of low-density lipoprotein (LDL)-cholesterol, triglycerides and lipoprotein(a). Clinical studies indicate that niacin can significantly reduce the risk for cardiovascular events. However, niacin is not very commonly used because of significant side effects (especially flushing). Laropiprant is a potent selective antagonist of PGD2-receptor subtype-1 and can thus reduce niacin-induced flushing. Although the addition of laropiprant will reduce the frequency of flushing, it will not completely eliminate this side effect. Laropiprant does not change the effect of niacin on lipids or other side effects of niacin (ie, gastro-intestinal problems, glucose elevation). The combination of niacin with laropiprant may therefore enable use of niacin at higher doses and therefore exploit the full potential of the drug. Endpoint studies that will be published over the next few years will show whether this treatment modality also translates into clinical effect in patients treated with statins. Until publication of these studies niacin/laropiprant should be used only in high-risk patients not achieving lipid goals on statins.
nicotinic acid; flushing; hyperlipidemia; dyslipoproteinemia
Obesity is associated with abnormal fasting and postprandial lipids, which may link obesity with atherosclerosis. We explored fasting and postprandial lipids in morbidly obese patients treated with sleeve gastrectomy and in control subjects.
After fasting for 12 h 15 morbidly obese patients (BMI 51.4±6.5 kg/m2, 43.7±12.6 years) received a standardized oral fat load before and 3 months after bariatric surgery (sleeve gastrectomy). Controls (n=9, BMI 23.1±1.4 kg/m2) were studied once. Plasma was obtained fasting and then postprandially every 2 h for 8 h. Triglycerides (TG), chylomicron-TG (CM-TG), VLDL/chylomicron-remnant (VLDL/CR)-TG, cholesterol, LDL-cholesterol, VLDL/CR-cholesterol and HDL-cholesterol were isolated by ultracentrifugation at each time point. Postprandial values were expressed as area under the curve (AUC) and incremental area under the curve (iAUC). In addition, fasting glucose and insulin values and HOMA-IR-Index was measured (n=14).
Compared to controls morbidly obese patients had elevated TG and slightly altered postprandial lipids. Following surgery (weight loss 23.4 kg±6.2 kg; p<0.001) fasting TG (−19.1%; p=0.04), VLDL/CR-TG (−20.0%; p=0.05) decreased significantly, while fasting cholesterol, VLDL-, HDL- and LDL-cholesterol did not change. AUC and iAUC decreased significantly for VLDL/CR-TG (−20.4%, p=0.04 and −38.5%, p=0.04, respectively). Neither fasting nor postprandial changes correlated with the change in weight. In patients with preoperatively elevated TG (>150 mg/dl) a similar pattern was observed. Fasting insulin and HOMA were reduced significantly (−51.9%; p=0.004 and −47.9%; p=0.011).
Three months after sleeve gastrectomy fasting and postprandial lipoprotein metabolism and glucose metabolism is improved in morbidly obese patients. The potential mechanisms may relate to decreased caloric intake but also to hormonal changes.
Postprandial lipids; Chylomicron; Chylomicron remnant; Dyslipidemia; VLDL-triglycerides
USCOM is an ultrasound-based method which has been accepted for noninvasive hemodynamic monitoring in various clinical conditions (USCOM, Ultrasonic cardiac output monitoring). The present study aimed at comparing the accuracy of the USCOM device with that of the thermodilution technique in patients with septicemia. We conducted a prospective observational study in a medical but noncardiological ICU of a university hospital. Septic adult patients (median age 55 years, median SAPS-II-Score 43 points) on mechanical ventilation and catecholamine support were monitored with USCOM and PiCCO (n = 70). Seventy paired left-sided CO measurements (transaortic access = COUS-A) were obtained. The mean COUS-A were 6.55 l/min (±2.19) versus COPiCCO 6.5 l/min (±2.18). The correlation coefficient was r = 0.89. Comparison by Bland-Altman analysis revealed a bias of −0.36 l/min (±0.99 l/min) leading to a mean percentage error of 29%. USCOM is a feasible and rapid method to evaluate CO in septic patients. USCOM does reliably represent CO values as compared to the reference technique based on thermodilution (PiCCO). It seems to be appropriate in situations where CO measurements are most pertinent to patient management.
Chemerin is a recently discovered hepatoadipokine that regulates adipocyte differentiation as well as chemotaxis and activation of dendritic cells and macrophages. Chemerin was reported to modulate insulin sensitivity in adipocytes and skeletal muscle cells in vitro and to exacerbate glucose intolerance in several mouse models in vivo. In humans, chemerin was shown to be associated with multiple components of the metabolic syndrome including BMI, triglycerides, HDL cholesterol, and hypertension. This study aimed to examine the effect of chemerin on weight, glucose and lipid metabolism, as well as atherosclerosis in vivo.
RESEARCH DESIGN AND METHODS
We used recombinant adeno-associated virus to express human chemerin in LDL receptor knockout mice on high-fat diet.
Expression of chemerin did not significantly alter weight, lipid levels, and extent of atherosclerosis. Chemerin, however, significantly increased glucose levels during the intraperitoneal glucose tolerance test without affecting endogenous insulin levels and the insulin tolerance test. Chemerin reduced insulin-stimulated Akt1 phosphorylation and activation of 5′AMP-activated protein kinase (AMPK) in the skeletal muscle, but had no effect on Akt phosphorylation and insulin-stimulated AMPK activation in the liver and gonadal adipose tissue.
Chemerin induces insulin resistance in the skeletal muscle in vivo. Chemerin is involved in the cross talk between liver, adipose tissue, and skeletal muscle.
The members of the Suppressor of Cytokine Signaling (SOCS) protein family mainly modulate the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. SOCS-1 and SOCS-3 have already been shown to influence growth and apoptosis of pancreatic β-cells. We hypothesized that SOCS-2, which is expressed in pancreatic islets, also contributes to β-cell physiology. We tested this hypothesis in vivo in SOCS-2−/− knockout mice and in vitro in Ins-1E rat insulinoma cells. We found that SOCS-2−/− mice have normal islet insulin secretion and unchanged glucose and insulin tolerance compared to wildtype controls. SOCS-2−/− are bigger than wildtype mice but body weight-corrected β-cell mass and islet morphology were normal. Growth hormone-induced proliferation of Ins-1E cells was not affected by either siRNA-mediated SOCS-2 knockdown or stable SOCS-2 overexpression. Interleukin-1β mediated cell death in vitro was unchanged after SOCS-2 knockdown. Similarly, autoimmune destruction of β-cells in vivo after multiple low-dose injections of streptozotocin (STZ) was not altered in SOCS-2−/− mice.
In summary, SOCS-2−/− knockout mice have a normal function of insulin-producing pancreatic β-cells, a fully adapted β-cell mass and a normal morphology of the endocrine islets. Based on in vitro evidence, the increased β-cell mass in the mutants is likely due to indirect adaptive mechanisms and not the result of altered growth hormone signaling within the β-cells. Immune mediated β-cell destruction is also not affected by SOCS-2 ablation in vitro and in vivo.
SOCS1; SOCS2; SOCS3; C57Bl/6; α-cell; δ-cell; glucagon; somatostatin; pancreatic polypeptide
Although diabetic patients have an increased rate of cardio-vascular events, there is considerable heterogeneity with respect to cardiovascular risk, requiring new approaches to individual cardiovascular risk factor assessment. In this study we used whole body-MR-angiography (WB-MRA) to assess the degree of atherosclerosis in patients with long-standing diabetes and to determine the association between metabolic syndrome (MetS) and atherosclerotic burden.
Long standing (≥10 years) type 1 and type 2 diabetic patients (n = 59; 31 males; 63.3 ± 1.7 years) were examined by WB-MRA. Based on the findings in each vessel, we developed an overall score representing the patient's vascular atherosclerotic burden (MRI-score). The score's association with components of the MetS was assessed.
The median MRI-score was 1.18 [range: 1.00-2.41] and MetS was present in 58% of the cohort (type 2 diabetics: 73%; type 1 diabetics: 26%). Age (p = 0.0002), HDL-cholesterol (p = 0.016), hypertension (p = 0.0008), nephropathy (p = 0.0093), CHD (p = 0.001) and MetS (p = 0.0011) were significantly associated with the score. Adjusted for age and sex, the score was significantly (p = 0.02) higher in diabetics with MetS (1.450 [1.328-1.572]) compared to those without MetS (1.108 [0.966-1.50]). The number of MetS components was associated with a linear increase in the MRI-score (increase in score: 0.09/MetS component; r2 = 0.24, p = 0.038). Finally, using an established risk algorithm, we found a significant association between MRI-score and 10-year risk for CHD, fatal CHD and stroke.
In this high-risk diabetic population, WB-MRA revealed large heterogeneity in the degree of systemic atherosclerosis. Presence and number of traits of the MetS are associated with the extent of atherosclerotic burden. These results support the perspective that diabetic patients are a heterogeneous population with increased but varying prevalence of atherosclerosis and risk.
The transcription factor Pax6 functions in the specification and maintenance of the differentiated cell lineages in the endocrine pancreas. It has two DNA binding domains, the paired domain and the homeodomain, in addition to a C-terminal transactivation domain. The phenotype of Pax6-/- knockout mice suggests non-redundant functions of the transcription factor in the development of glucagon-expressing α-cells as this cell type is absent in the mutants. We ask the question of how the differentiation of pancreatic endocrine cells, in particular that of α-cells, is affected by selective inactivation of either one of the three major domains of Pax6.
The Pax6Aey18 mutant mouse line, in which the paired domain is inactivated, showed a phenotype similar to that of Pax6-/- knockout mice with a near complete absence of glucagon-positive α-cells (0-4 cells/section; ≤1% of wt), reduced β-cell area (74% of wt) and disorganized islets. The proportion of ghrelin-positive ε-cells was expanded. In Pax6Sey-Neu mutants, which lack the transactivation domain, α-and β-cells where reduced to 25 and 40% of wt, respectively. We also studied two mouse lines with mutations in the homeodomain, Pax64Neu and Pax6132-14Neu. Neighboring amino acids are affected in the two lines and both point mutations abolish DNA binding of the classical P3 homeodomain target sequence. The pancreatic phenotype of the two mutants however was divergent. While Pax64Neu homozygotes showed a reduction of α- and β-cells to 59 and 61%, respectively, pancreatic endocrine development was unaltered in the Pax6132-14Neu mutant strain.
We show that inactivation of the Pax6 paired domain leads to a more severe phenotype with regards to the differentiation of pancreatic α-cells than the loss of the transactivation domain. The analysis of two different homeodomain mutants suggests that the binding of Pax6 to P3 homeodomain consensus sequences is not required for α-cell development. It rather seems that the homeodomain has a modulating role in Pax6 function, possibly by facilitating a PH0-like binding confirmation on paired domain target genes like proglucagon. This function is differentially affected by the two homeodomain mutations analyzed in this study.
Atherosclerosis is the primary cause of coronary artery disease (CAD). There is increasing recognition that lesion composition rather than size determines the acute complications of atherosclerotic disease. Low serum adiponectin levels were reported to be associated with coronary artery disease and future incidence of acute coronary syndrome (ACS). The impact of adiponectin on lesion composition still remains to be determined.
We measured serum adiponectin levels in 303 patients with stable typical or atypical chest pain, who underwent dual-source multi-slice CT-angiography to exclude coronary artery stenosis. Atherosclerotic plaques were classified as calcified, mixed or non-calcified. In bivariate analysis adiponectin levels were inversely correlated with total coronary plaque burden (r = −0.21, p = 0.0004), mixed (r = −0.20, p = 0.0007) and non-calcified plaques (r = −0.18, p = 0.003). No correlation was seen with calcified plaques (r = −0.05, p = 0.39). In a fully adjusted multivariate model adiponectin levels remained predictive of total plaque burden (estimate: −0.036, 95%CI: −0.052 to −0.020, p<0.0001), mixed (estimate: −0.087, 95%CI: −0.132 to −0.042, p = 0.0001) and non-calcified plaques (estimate: −0.076, 95%CI: −0.115 to −0.038, p = 0.0001). Adiponectin levels were not associated with calcified plaques (estimate: −0.021, 95% CI: −0.043 to −0.001, p = 0.06). Since the majority of coronary plaques was calcified, adiponectin levels account for only 3% of the variability in total plaque number. In contrast, adiponectin accounts for approximately 20% of the variability in mixed and non-calcified plaque burden.
Adiponectin levels predict mixed and non-calcified coronary atherosclerotic plaque burden. Low adiponectin levels may contribute to coronary plaque vulnerability and may thus play a role in the pathophysiology of ACS.
Obesity is associated with an array of health problems in adult and pediatric populations. Understanding the pathogenesis of obesity and its metabolic sequelae has advanced rapidly over the past decades. Adipose tissue represents an active endocrine organ that, in addition to regulating fat mass and nutrient homeostasis, releases a large number of bioactive mediators (adipokines) that signal to organs of metabolic importance including brain, liver, skeletal muscle, and the immune system—thereby modulating hemostasis, blood pressure, lipid and glucose metabolism, inflammation, and atherosclerosis. In the present review, we summarize current data on the effect of the adipose tissue-derived hormones adiponectin, chemerin, leptin, omentin, resistin, retinol binding protein 4, tumor necrosis factor-α and interleukin-6, vaspin, and visfatin on insulin resistance.
A number of intervention studies have shown that therapy with angiotensin receptor blockers, such as irbesartan, can improve metabolic parameters and reduce the incidence of diabetes mellitus. It is unknown whether this observation also holds true in routine clinical settings.
We evaluated the effect of irbesartan (150 mg or 300 mg/d) together with or without hydrochlorothiazide (12.5 mg/d) in 3259 German patients. A total of 750 primary care physicians evaluated up to 5 subsequent patients with metabolic syndrome (58.9% diabetic), in whom irbesartan therapy was newly initiated (87%) or continued (13%).
Six months of irbesartan therapy decreased systolic blood pressure by 14% (157.4 ± 14.7 vs. 135.0 ± 10.7 mmHg) and diastolic blood pressure by 13% (92.9 ± 9.2 vs. 80.8 ± 6.8 mmHg). This was associated with a decrease in body weight (-2.3%), fasting glucose (-9.5%), HbA1c (-4.6%), LDL-cholesterol (-11%), triglycerides (-16%) and gamma-GT (-12%) and an increase in HDL-cholesterol (+5%). These changes were somewhat more pronounced in male than in female patients and in obese than in lean patients. Changes in glucose concentration and HbA1c were much more prominent in diabetic patients.
Irbesartan therapy improves metabolic parameters in routine clinical settings. Thus, our study confirms previously published results from large intervention trials and extends the findings to routine clinical practice.
In primary prevention of atherosclerotic disease, it is difficult to decide when medical treatment should be initiated. The main goal of the study was to compare different guidelines for coronary heart disease (CHD) risk assessment and initiation of lipid-lowering therapy.
An outpatient lipid and diabetes clinic in a university hospital.
Risk factor data obtained on 100 consecutive patients (58 men and 42 women) without clinical evidence of cardiovascular disease were used to compare the Framingham risk equation, the U.S. National Cholesterol Education Program (Adult Treatment Panel III) (NCEP ATP III) guidelines, the joint European Societies guidelines, the joint British guidelines, the revised Sheffield table, and the Munster Heart Study calculator (PROCAM) CHD risk assessment and lipid-lowering therapy.
Guidelines could be applied to different subsets of the cohort, ranging from 22% (PROCAM) to 95% of the cohort (revised Sheffield table). All guidelines (except PROCAM) could be applied to a total of 62 patients. Guidelines predicted ≥20% risk for developing CHD over 10 years in 53% (NCEP ATP III), 26% (European) and 32% (British), while Framingham predicted this risk level in 34%. CHD risk was estimated to be ≥3%/year in 5% according to Sheffield, while Framingham predicted this risk in 13%. Lipid-lowering drug therapy is recommended in 52% by NCEP ATP III, while European, British, and Sheffield guidelines recommend this in 26%, 35%, and 5%, respectively.
Guidelines for assessing CHD risk and lipid-lowering therapy differ greatly. Therefore, these algorithms must be used with caution.
atherosclerosis; guideline; coronary heart disease; risk assessment; primary prevention; lipid-lowering therapy
Diabetic dyslipoproteinemia is characterized by hypertriglyceridemia, low HDL-cholesterol and often elevated LDL-cholesterol and is a strong risk factor for atherosclerosis. Adhesion molecule levels are elevated both in hyperlipoproteinemia and diabetes mellitus. It is unclear whether fibrate or statin therapy has more beneficial effects on adhesion molecule concentrations.
Atorvastatin (10 mg/d) was compared to fenofibrate (200 mg/d) each for 6 weeks separated by a 6 week washout period in 11 patients (6 male, 5 female; 61.8 ± 8.2 years; body mass index 29.8 ± 3.1 kg/m2) with type 2 diabetes mellitus (HbA1c 7.3 ± 1.1 %) and mixed hyperlipoproteinemia using a randomized, cross-over design. Fasting blood glucose, HbA1c, lipid parameters, E-selectin, ICAM-1, VCAM-1, and fibrinogen concentrations were determined before and after each drug.
Glucose and HbA1c concentrations remained unchanged during the whole study period. LDL cholesterol was reduced during atorvastatin therapy, triglycerides were lowered more effectively with fenofibrate. Comparison of pre- and postreatment concentrations of E-selectin showed a reduction during atorvastatin (-7 %, p = 0.11) and fenofibrate (-10 %, p < 0.05) therapy. Atorvastatin treatment reduced VCAM-1 levels by 4% (p < 0.05), while VCAM-1 concentrations remained unchanged (+1%, ns) during fenofibate therapy. However, direct comparisons of post-treatment levels during both forms of therapy were not of statistical significance. ICAM-1 levels were not influenced by either form of therapy.
In addition to the different beneficial effects on lipid metabolism, both drugs appear to lower adhesion molecule plasma concentrations in a different manner in patients with type 2 diabetes and mixed hyperlipoproteinemia. Our observations should be confirmed in a larger cohort of such patients.
GLP-1 is an incretine hormone which gets secreted from intestinal L-cells in response to nutritional stimuli leading to pancreatic insulin secretion and suppression of glucagon release. GLP-1 further inhibits gastric motility and reduces appetite which in conjunction improves postprandial glucose metabolism. Additional vasoprotective effects have been described for GLP-1 in experimental models. Despite these vasoprotective actions, associations between endogenous levels of GLP-1 and cardiovascular disease have yet not been investigated in humans which was the aim of the present study.
GLP-1 serum levels were assessed in a cohort of 303 patients receiving coronary CT-angiography due to typical or atypical chest pain.
GLP-1 was found to be positively associated with total coronary plaque burden in a fully adjusted model containing age, sex, BMI, hypertension, diabetes mellitus, smoking, triglycerides, LDL-C (low density lipoprotein cholesterol), hsCRP (high-sensitive C-reactive protein), and eGFR (estimated glomerular filtration rate) (OR: 2.53 (95% CI: 1.12 – 6.08; p = 0.03).
Circulating GLP-1 was found to be positivity associated with coronary atherosclerosis in humans. The clinical relevance of this observation needs further investigations.
GLP-1; Atherosclerosis; Coronary CT angiography
Myocardial infarction results as a consequence of atherosclerotic plaque rupture, with plaque stability largely depending on the lesion forming extracellular matrix components. Lipid enriched non-calcified lesions are considered more instable and rupture prone than calcified lesions. Matrix metalloproteinases (MMPs) are extracellular matrix degrading enzymes with plaque destabilisating characteristics which have been implicated in atherogenesis. We therefore hypothesised MMP-1 and MMP-9 serum levels to be associated with non-calcified lesions as determined by CT-angiography in patients with coronary artery disease.
260 patients with typical or atypical chest pain underwent dual-source multi-slice CT-angiography (0.6-mm collimation, 330-ms gantry rotation time) to exclude coronary artery stenosis. Atherosclerotic plaques were classified as calcified, mixed or non-calcified.
In multivariable regession analysis, MMP-1 serum levels were associated with total plaque burden (OR: 1.37 (CI: 1.02-1.85); p < 0.05) in a model adjusted for age, sex, BMI, classical cardiovascular risk factors, hsCRP, adiponectin, pericardial fat volume and medication. Specification of plaque morphology revealed significant association of MMP-1 serum levels with non-calcified plaques (OR: 1.16 (CI: 1.0-1.34); p = 0.05) and calcified plaques (OR: 1.22 (CI: 1,03-1.45); p < 0.05) while association with mixed plaques was lost in the fully adjusted model. No associations were found between MMP9 serum levels and total plaque burden or plaque morphology.
MMP-1 serum levels are associated with total plaque burden but do not allow a specification of plaque morphology.
Inflammatory stimuli are causative for insulin resistance in obesity as well as in acute inflammatory reactions. Ongoing research has identified a variety of secreted proteins that are released from immune cells and adipocytes as mediators of insulin resistance; however, knowledge about their relevance for acute inflammatory insulin resistance remains limited. In this study we aimed for a clarification of the relevance of different insulin resistance mediating factors in an acute inflammatory situation.
Insulin resistance was measured in a cohort of 37 non-diabetic patients undergoing cardiac surgery by assessment of insulin requirement to maintain euglycaemia and repeated measurements of an insulin glycaemic index. The kinetics of cortisol, interleukin 6 (IL6), tumour necrosis factor α (TNFα), resistin, leptin and adiponectin were assessed by repeated measurements in a period of 48 h.
Insulin resistance increased during the observation period and peaked 22 h after the beginning of the operation. IL6 and TNFα displayed an early increase with peak concentrations at the 4-h time point. Serum levels of cortisol, resistin and leptin increased more slowly and peaked at the 22-h time point, while adiponectin declined, reaching a base at the 22-h time point. Model assessment identified cortisol as the best predictor of insulin resistance, followed by IL6, leptin and adiponectin. No additional information was gained by modelling for TNFα, resistin, catecholamine infusion rate, sex, age, body mass index (BMI), operation time or medication.
Serum cortisol levels are the best predictor for inflammatory insulin resistance followed by IL6, leptin and adiponectin. TNFα, and resistin have minor relevance as predictors of stress dependent insulin resistance.
Adiponectin acts as an antidiabetic, antiinflammatory and antiatherogenic adipokine. These effects are assumed to be mediated by the recently discovered adiponectin receptors AdipoR1 and AdipoR2.
The purpose of this study was to determine whether variations in the AdipoR1 and AdipoR2 genes may contribute to insulin resistance, dyslipidemia and inflammation.
We sequenced all seven coding exons of both genes in 20 unrelated German subjects with metabolic syndrome and tested genetic variants for association with glucose, lipid and inflammatory parameters.
We identified three AdipoR2 variants (+795G/A, +870C/A and +963C/T) in perfect linkage disequilibrium (r2 = 1) with a minor allele frequency of 0.125. This haplotype was associated with higher plasma adiponectin levels and decreased fasting triglyceride, VLDL-triglyceride and VLDL-cholesterol levels. No association, however, was observed between the AdipoR2 SNP cluster and glucose metabolism.
To our knowledge, this is the first study to identify an association between genetic variants of the adiponectin receptor genes and plasma adiponectin levels. Furthermore, our data suggest that AdipoR2 may play an important role in triglyceride/VLDL metabolism.