Accelerometer-derived physical activity and sedentary time and cardiac biomarkers: The Maastricht Study.

Background: Cardiac troponins and NT-proBNP are biomarkers of cardiac injury that are used clinically in the diagnosis of myocardial infarction and heart failure. It is not known whether the amount, types and patterns of physical activity (PA) and sedentary behaviour are associated with levels of cardiac biomarkers. Methods: In the population-based Maastricht Study (n = 2,370, 51.3% male, 28.3% T2D) we determined cardiac biomarkers hs-cTnI, hs-cTnT, and NT-proBNP. PA and sedentary time were measured by activPAL and divided into quartiles [quartile 1 (Q1) served as reference]. The weekly pattern of moderate-to-vigorous PA (insufficiently active; regularly actives; weekend warriors) and coefficient of variation (CV) was calculated. Linear regression analyses were conducted with adjustment for demographic, lifestyle, and cardiovascular risk factors. Results: There was no consistent pattern between physical activity (different intensities: total, light, moderate-to-vigorous and vigorous) and sedentary time on the one hand and hs-cTnI and hs-cTnT on the other. Those with the highest levels of vigorous intensity PA had significantly lower levels of NT-proBNP. With regard to PA patterns, weekend warriors and regularly actives had lower levels of NT-proBNP but not with hs-cTnI and hs-cTnT (reference:insufficiently actives). A higher weekly moderate-to-vigorous PA CV (indicating more irregular activity) was associated with lower levels of hs-cTnI and higher levels of NT-proBNP, but not with hs-cTnT. Conclusions: In general, there was no consistent association between PA and sedentary time and cardiac troponins. In contrast, vigorous and possibly moderate-to-vigorous intensity PA, especially if done regularly, were associated with lower levels of NT-proBNP.

Cognitive Functioning in Survivors of Hematopoietic Stem Cell Transplantation Compared With a Matched General Population Sample-The Maastricht Observational Study of Late Effects After Stem Cell trAnsplantation Study.

Although cognitive problems can recover over time, a subgroup of hematopoietic stem cell transplantation (HCT) survivors experience persistent cognitive problems in the long term. Despite these implications, studies assessing cognitive functioning in HCT survivors are limited. The aim of the present study was (1) to quantify the prevalence of cognitive impairment in patients treated with HCT who survived at least 2 years and to compare these with a matched reference group representing the general population; (2) to identify potential determinants of cognitive functioning within the HCT survivor group. Within the single-center Maastricht Observational study of late effects after Stem cell trAnsplantation, cognitive performance was assessed by a neuropsychological test battery divided into 3 cognitive domains: memory, information processing speed, and executive function and attention. An overall cognition score was calculated as the average of the domain scores. A total of 115 HCT survivors were group-matched on a 1:4 ratio to the reference group by age, sex, and level of education. Regression analyses adjusted for different sets of covariates including demographic and health- and lifestyle-related factors were used to test for differences in cognition between HCT survivors and the reference group resembling the general population. A limited set of clinical characteristics (diagnosis, type of transplant, time since treatment, conditioning regimen with total body irradiation and age at time of transplantation) were assessed as potential determinants of neurocognitive dysfunction among HCT survivors. Cognitive impairment was defined as scores in the cognitive domains < -1.5 standard deviation (SD) from what can be expected based on someone's age, sex, and education. The mean age at time of transplantation was 50.2 (SD ± 11.2) years, and the mean number of years after transplant was 8.7 (SD ± 5.7) years. The majority of HCT survivors were treated with autologous HCT (n = 73 [64%]). The prevalence of cognitive dysfunction was 34.8% in HCT survivors and 21.3% in the reference group (p = .002.) When adjusted for age, sex, and level of education, HCT survivors had a worse overall cognition score (b = -0.35; 95% confidence interval [CI], -0.55 to -0.16; p < .001), translating into 9.0 years of higher cognitive age. Analyses of specific cognitive domain scores showed that HCT survivors scored worse on memory (b = -0.43; 95% CI, -0.73 to -0.13; p = .005), information processing speed (b = -0.33; 95% CI, -0.55 to -0.11; p = .003), and executive function and attention (b = -0.29; 95% CI, -.55 to -.03; p = .031) than the reference group. The odds of cognitive impairment were on average 2.4 times higher among HCT survivors than the reference group (odd ratio = 2.44; 95% CI, 1.47-4.07; p = .001). Within the HCT survivor group none of the tested clinical determinants of cognitive impairment were significantly associated with cognition. This cohort study showed evidence for worse cognitive functioning in HCT survivors encompassing all three cognitive domains, respectively memory, information processing speed, and executive and attention compared to a reference group that represents the general population translating into nine years of faster cognitive ageing in HCT survivors than can be expected based on their chronological age. It is important to increase awareness for signs of neurocognitive dysfunction after HCT in clinicians and HCT survivors.

The hypoxia-sensor carbonic anhydrase IX affects macrophage metabolism, but is not a suitable biomarker for human cardiovascular disease.

Hypoxia is prevalent in atherosclerotic plaques, promoting plaque aggravation and subsequent cardiovascular disease (CVD). Transmembrane protein carbonic anhydrase IX (CAIX) is hypoxia-induced and can be shed into the circulation as soluble CAIX (sCAIX). As plaque macrophages are hypoxic, we hypothesized a role for CAIX in macrophage function, and as biomarker of hypoxic plaque burden and CVD. As tumor patients with probable CVD are treated with CAIX inhibitors, this study will shed light on their safety profile. CAIX co-localized with macrophages (CD68) and hypoxia (pimonidazole), and correlated with lipid core size and pro-inflammatory iNOS+ macrophages in unstable human carotid artery plaques. Although elevated pH and reduced lactate levels in culture medium of CAIX knock-out (CAIXko) macrophages confirmed its role as pH-regulator, only spare respiratory capacity of CAIXko macrophages was reduced. Proliferation, apoptosis, lipid uptake and expression of pro- and anti-inflammatory genes were not altered. Plasma sCAIX levels and plaque-resident CAIX were below the detection threshold in 50 and 90% of asymptomatic and symptomatic cases, respectively, while detectable levels did not associate with primary or secondary events, or intraplaque hemorrhage. Initial findings show that CAIX deficiency interferes with macrophage metabolism. Despite a correlation with inflammatory macrophages, plaque-resident and sCAIX expression levels are too low to serve as biomarkers of future CVD.

Irbesartan treatment does not influence plasma levels of the dicarbonyls methylglyoxal, glyoxal and 3-deoxyglucosone in participants with type 2 diabetes and microalbuminuria: An IRMA2 sub-study.

AIM: Angiotensin receptor blockers (ARBs) reduce vascular complications in diabetes independently of blood pressure. Experimental studies suggested that ARBs may restore the detoxifying enzyme glyoxalase 1, thereby lowering dicarbonyls such as methylglyoxal. Human data on the effects of ARBs on plasma dicarbonyl levels are lacking. We investigated, in individuals with type 2 diabetes, whether irbesartan lowered plasma levels of the dicarbonyls methylglyoxal, glyoxal, 3-deoxyglucosone and their derived advanced glycation end products (AGEs), and increased d-lactate, reflecting greater methylglyoxal flux. METHODS: We analysed a subset of the Irbesartan in Patients with T2D and Microalbuminuria (IRMA2) study. We measured plasma dicarbonyls methylglyoxal, glyoxal and 3-deoxyglucosone, free AGEs and d-lactate using ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) in the treatment arm receiving 300 mg irbesartan (n = 121) and a placebo group (n = 101) at baseline and after 1 and 2 years. Effect of treatment was analysed with repeated measurements ANOVA. RESULTS: There was a slight, but significant difference in baseline median methylglyoxal levels [placebo 1119 (907-1509) nmol/l vs. irbesartan 300 mg 1053 (820-1427) nmol/l], but no significant changes were observed in any of the plasma dicarbonyls over time in either group and there was no effect of irbesartan treatment on plasma free AGEs or d-lactate levels at either 1 or 2 years. CONCLUSION: Irbesartan treatment does not change plasma levels of the dicarbonyls methylglyoxal, glyoxal and 3-deoxyglucosone, free AGEs or d-lactate in type 2 diabetes. This indicates that increased dicarbonyls in type 2 diabetes are not targetable by ARBs, and other approaches to lower systemic dicarbonyls are needed in type 2 diabetes. (Clinical Trial Registry No: #NCT00317915).

Fasting and post-oral-glucose-load levels of methylglyoxal are associated with microvascular, but not macrovascular, disease in individuals with and without (pre)diabetes: The Maastricht Study.

AIMS: Reactive dicarbonyl compounds, such as methylglyoxal (MGO), rise during an oral glucose tolerance test (OGTT), particularly in (pre)diabetes. Fasting MGO levels are associated with chronic kidney disease (CKD) and cardiovascular disease (CVD) in patients with poorly controlled type 2 diabetes mellitus (T2DM). Yet, whether fasting or post-OGTT plasma MGO levels are associated with vascular disease in people with (pre)diabetes is unknown. METHODS: Subjects with normal glucose metabolism (n=1796; age: 57.9±8.2 years; 43.3% men), prediabetes (n=478; age: 61.6±7.6 years; 54.0% men) and T2DM (n=669; age: 63.0±7.5 years; 67.0% men) from the Maastricht Study underwent OGTTs. Plasma MGO levels were measured at baseline and 2h after OGTT by mass spectrometry. Prior CVD was established via questionnaire. CKD was reflected by estimated glomerular filtration rate (eGFR) and albuminuria; retinopathy was assessed using retinal photographs. Data were analyzed using logistic regression adjusted for gender, age, smoking, systolic blood pressure, total-to-HDL cholesterol ratio, triglycerides, HbA1c, BMI and medication use. Odd ratios (ORs) were expressed per standard deviation of LN-transformed MGO. RESULTS: Fasting and post-OGTT MGO levels were associated with higher ORs for albuminuria ≥30mg/24h [fasting: 1.12 (95% CI: 0.97-1.29); post-OGTT: 1.19 (1.01-1.41)], eGFR<60mL/min/1.73 m2 [fasting: 1.58 (95% CI: 1.38-1.82), post-OGTT: 1.57 (1.34-1.83)] and retinopathy [fasting: 1.59 (95% CI: 1.01-2.53), post-OGTT: 1.38 (0.77-2.48)]. No associations with prior CVD were found. CONCLUSION: Fasting and post-OGTT MGO levels were associated with microvascular disease, but not prior CVD. Thus, therapeutic strategies directed at lowering MGO levels may prevent microvascular disease.

The complement system in human cardiometabolic disease.

The complement system has been implicated in obesity, fatty liver, diabetes and cardiovascular disease (CVD). Complement factors are produced in adipose tissue and appear to be involved in adipose tissue metabolism and local inflammation. Thereby complement links adipose tissue inflammation to systemic metabolic derangements, such as low-grade inflammation, insulin resistance and dyslipidaemia. Furthermore, complement has been implicated in pathophysiological mechanisms of diet- and alcohol induced liver damage, hyperglycaemia, endothelial dysfunction, atherosclerosis and fibrinolysis. In this review, we summarize current evidence on the role of the complement system in several processes of human cardiometabolic disease. C3 is the central component in complement activation, and has most widely been studied in humans. C3 concentrations are associated with insulin resistance, liver dysfunction, risk of the metabolic syndrome, type 2 diabetes and CVD. C3 can be activated by the classical, the lectin and the alternative pathway of complement activation; and downstream activation of C3 activates the terminal pathway. Complement may also be activated via extrinsic proteases of the coagulation, fibrinolysis and the kinin systems. Studies on the different complement activation pathways in human cardiometabolic disease are limited, but available evidence suggests that they may have distinct roles in processes underlying cardiometabolic disease. The lectin pathway appeared beneficial in some studies on type 2 diabetes and CVD, while factors of the classical and the alternative pathway were related to unfavourable cardiometabolic traits. The terminal complement pathway was also implicated in insulin resistance and liver disease, and appears to have a prominent role in acute and advanced CVD. The available human data suggest a complex and potentially causal role for the complement system in human cardiometabolic disease. Further, preferably longitudinal studies are needed to disentangle which aspects of the complement system and complement activation affect the different processes in human cardiometabolic disease.

Obesity-associated low-grade inflammation in type 2 diabetes mellitus: causes and consequences.

The epidemic of overweight and obesity is a major problem because of the plethora of health and economic issues that it induces. Key among these is the sharply increasing prevalence of type 2 diabetes (T2D) and cardiovascular disease. The development of T2D is characterised by two processes: 1) insulin resistance, resulting from impaired insulin signalling and leading to an increased demand for insulin, which must be met by increased insulin production by pancreatic ß-cells (compensatory ß-cell function); and 2) ß-cell dysfunction, with T2D developing when the amount of insulin that is produced is insufficient to meet the demand. Overweight and obesity, especially in case of abdominal fat accumulation, are associated with systemic low-grade inf lammation. This low-grade inf lammation is characterised by, among other things, higher levels of circulating proinflammatory cytokines and fatty acids. These can interfere with normal insulin function and thereby induce insulin resistance, and have also been implicated in ß-cell dysfunction. This review focuses on the known and emerging relations between inflammation and T2D. We first discuss current views on the effects of fat distribution on adipose tissue inflammation and adipose tissue dysfunction. Next we focus on the detrimental roles of proinflammatory cytokines and fatty acids on insulin signalling and ß-cell function. In the last part of this review we provide some insight into novel players in (the initiation of) inflammation in overweight and obesity, and their effects on T2D and vascular dysfunction.

Plasma proprotein convertase subtilisin kexin type 9 levels are related to markers of cholesterol synthesis in familial combined hyperlipidemia.

BACKGROUND AND AIMS: Two recent independent studies showed that patients with familial combined hyperlipidemia (FCHL) have elevated plasma levels of proprotein convertase subtilisin kexin type 9 (PCSK9) and markers of cholesterol synthesis. Both PCSK9 expression and cholesterol synthesis are downstream effects of hepatic activation of sterol regulatory element binding protein 2 (SREBP2). The present study was conducted to study the relationship between plasma PCSK9 and markers of cholesterol synthesis in FCHL. METHODS AND RESULTS: Markers of cholesterol synthesis (squalene, desmosterol, lathosterol), cholesterol absorption (campesterol, sitosterol, cholestanol) and PCSK9 were measured in plasma of FCHL patients (n = 103) and their normolipidemic relatives (NLR; n = 240). Plasma PCSK9, lathosterol and desmosterol levels were higher in FCHL patients than their NLR (p < 0.001, age and sex adjusted). Heritability calculations demonstrated that 35% of the variance in PCSK9 levels could be explained by additive genetic effects (p < 0.001). Significant age- and sex-adjusted correlations were observed for the relationship between PCSK9 and lathosterol, both unadjusted and adjusted for cholesterol, in the overall FCHL population (both p < 0.001). Multivariate regression analyses, with PCSK9 as the dependent variable, showed that the regression coefficient for FCHL status decreased by 25% (from 0.8 to 0.6) when lathosterol was included. Nevertheless, FCHL status remained an independent contributor to plasma PCSK9 (p < 0.001). CONCLUSIONS: The present study confirms the previously reported high and heritable PCSK9 levels in FCHL patients. Furthermore, we now show that high PCSK9 levels are, in part, explained by plasma lathosterol, suggesting that SREBP2 activation partly accounts for elevated PCSK9 levels in FCHL.

Up-regulation of the complement system in subcutaneous adipocytes from nonobese, hypertriglyceridemic subjects is associated with adipocyte insulin resistance.

BACKGROUND: Dysfunctional adipose tissue plays an important role in the etiology of the metabolic syndrome, type 2 diabetes, and dyslipidemia. However, the molecular mechanisms underlying adipocyte dysfunction are incompletely understood. AIM: The aim of the study was to identify differentially regulated pathways in sc adipocytes of dyslipidemic subjects. METHODS: Whole-genome expression profiling was conducted on sc adipocytes from a discovery group of nine marginally overweight subjects with familial combined hyperlipidemia (FCHL) and nine controls of comparable body sizes as well as two independent confirmation groups. In this study, FCHL served as a model of familial insulin resistance and dyslipidemia, in the absence of frank obesity. RESULTS: Functional analyses and gene set enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes or a custom pathway database identified the complement system and complement regulators as one of the top up-regulated pathways in FCHL [false discovery rate (FDR) < 1E-30]. Higher adipocyte complement expression in FCHL was confirmed in the appropriate confirmation group. Higher complement gene expression was associated with lower adipocyte insulin receptor substrate-1 expression as marker of adipocyte insulin resistance, independent of age, sex, or disease status, and this association was corroborated in the two confirmation groups. Additionally, complement gene expression was associated with triglycerides in the discovery set and with triglycerides and/or waist circumference in the confirmation groups. Complement pathway up-regulation did not appear to be driven by hypertriglyceridemia because a 40% pharmacological reduction in triglycerides did not affect complement expression. CONCLUSIONS: These findings point to an up-regulation of a complement-related transcriptome in sc adipocytes under metabolically stressed conditions, even in the absence of overt obesity. Such up-regulation may subsequently influence downstream processes, including macrophage infiltration into adipose tissue and adipocyte insulin resistance.

Complement C3: an emerging risk factor in cardiometabolic disease.

C3 is the central component of the complement system and activation of C3 via any of the three major activation pathways-the classical, the lectin and the alternative pathways-results in initiation of the terminal complement pathway and release of the anaphylatoxin C3a. Both terminal pathway activation and signalling of C3a and its inactivation product C3a-desarg via the C3a receptor and C5a-like receptor 2, respectively, can induce inflammatory, immunomodulatory and metabolic responses. C3 has been implicated in metabolic disorders, notably adiposity, dyslipidaemia, insulin resistance, liver dysfunction and diabetes, and C3 is increasingly recognised as a cardiometabolic risk factor. C3 may play a role in the macrovascular, as well as microvascular, complications of diabetes. Moreover, C3 may interact with the coagulation system and as such also contribute to a procoagulant, hypofibrinolytic and, ultimately, prothrombotic state. Recent data suggest a diabetes-dependent incorporation of C3 into fibrin clots, with concomitant effects on clot characteristics. Taken together, epidemiological and experimental evidence concordantly point to a role of complement C3 in metabolic, atherosclerotic/atherothrombotic and microangiopathic processes and further research should be directed towards the elucidation of complement function and activation in cardiometabolic disorders.

Plasma proprotein convertase subtilisin kexin type 9 is not altered in subjects with impaired glucose metabolism and type 2 diabetes mellitus, but its relationship with non-HDL cholesterol and apolipoprotein B may be modified by type 2 diabetes mellitus: The CODAM study.

OBJECTIVE: Type 2 diabetes mellitus (T2DM) is associated with elevated plasma apolipoprotein B and triglycerides levels, reduced HDL cholesterol and the presence of small-dense LDL particles. The present study was conducted to investigate the role of plasma proprotein convertase subtilisin kexin type 9 (PCSK9) levels, a regulator of LDL-receptor expression, in the occurrence of diabetic dyslipidemia. METHODS: Plasma PCSK9 was measured in a cohort of subjects with normal glucose metabolism (NGM; n=288), impaired glucose metabolism (IGM; n=121) and type 2 diabetes mellitus (T2DM; n=139) to study whether its relation with plasma apolipoprotein B, triglycerides, total cholesterol, non-HDL cholesterol, LDL cholesterol and HDL cholesterol differed by levels of glucose metabolism status. RESULTS: Plasma PCSK9 levels were not different between the three groups (82, 82 and 80 ng/mL in NGM, IGM and T2DM, respectively). PCSK9 was positively associated with total cholesterol, non-HDL cholesterol, LDL cholesterol, apolipoprotein B and triglycerides levels in all subgroups. The regression slopes for the associations with non-HDL cholesterol were steeper among individuals with T2DM than with NGM (ß = 0.016 versus ß=0.009, p-interaction=0.05). Similar results were obtained for the relation with apolipoprotein B (ß = 0.004 versus ß = 0.002, p-interaction=0.09). CONCLUSIONS: Although glucose metabolism status per se is not associated with plasma PCSK9 levels, the presence of T2DM may modify the relation between plasma PCSK9 and non-HDL cholesterol and apolipoprotein B. These observations should be regarded as hypothesis generating for further studies aimed at elucidating the role of PCSK9 in the pathogenesis and treatment of diabetic dyslipidemia.

Five-year incidence of type 2 diabetes mellitus in patients with familial combined hyperlipidaemia.

BACKGROUND: The current study was conducted to investigate whether patients with familial combined hyperlipidaemia (FCHL ) are predisposed to the development of type 2 diabetes mellitus (T2DM). METHODS: A cohort of 56 FCHL patients and 54 spouses was followed over time with a five-year interval. Diagnosis of T2DM was based on fasting glucose levels or use of antidiabetic medication. Baseline body mass index, waist circumference, blood pressure, use of antihypertensive and lipid-lowering medication, plasma cholesterol, triglycerides, apolipoprotein B, glucose, insulin and alanine aminontransferase (ALAT) levels were determined as potential predictors of new onset T2DM. RESULTS: Baseline prevalence of T2DM was 2% in spouses and 9% in FCHL patients, and 4 and 20%, respectively, after five-year follow-up. The incidence of T2DM was significantly higher in FCHL patients (2 vs 14%; OR 9.1; 95% CI 1.0 to 81.4; p=0.04; age and sex adjusted). Of all baseline variables, only plasma insulin levels (not glucose) significantly predicted the development of T2DM (p=0.04). CONCLUSION: The present study is the first to present incidence numbers of T2DM in FCHL and demonstrates that FCHL patients, as compared with healthy controls, are predisposed to the development of T2DM. This is - at least in part - accounted for by an increased insulin resistance.

Low-grade inflammation can partly explain the association between the metabolic syndrome and either coronary artery disease or severity of peripheral arterial disease: the CODAM study.

BACKGROUND: Low-grade inflammation has been hypothesized to underlie the coronary artery disease (CAD) risk associated with the metabolic syndrome, but the evidence is not conclusive. For peripheral arterial disease (PAD; as measured by the ankle-arm index), this association has not been studied before. The aim was to study whether the association between the metabolic syndrome and CAD or the severity of PAD can be explained by low-grade inflammation. METHODS: The Cohort study Diabetes and Atherosclerosis Maastricht population includes 574 subjects, with an increased risk of type 2 diabetes, of whom 560 were included in the analyses (343 males; age: 59.5 +/- 7.0 years). The inflammation markers that were measured were C-reactive protein, interleukin 6, soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1 and serum amyloid A. All analyses were adjusted for age, sex and smoking. RESULTS: Logistic regression showed that the metabolic syndrome was significantly associated with CAD [odds ratio (OR) = 1.86, 95% CI: 1.21; 2.84, P = 0.004]. Further adjustment for inflammatory status, as captured in a combination of the inflammation markers (using an averaged Z-score), resulted in significant associations of both the metabolic syndrome and inflammatory status with CAD [OR(metabolic syndrome) (95% CI) = 1.58 (1.01; 2.46), P = 0.044; OR(inflammation) (95% CI) = 1.59 (1.14; 2.21), P = 0.007]. Linear regression analysis showed similar results for the ankle-arm index. CONCLUSIONS: The association between the metabolic syndrome, on the one hand, and prevalence of CAD or the severity of PAD, on the other, can be partly but not completely, 26% and 29% respectively, explained by low-grade inflammation.

Plasma triglycerides and LDL cholesterol are related in a parabolic fashion in the general population and patients with Type 2 diabetes mellitus: long-term follow-up results from the Hoorn study.

AIMS: Low-density lipoprotein cholesterol (LDL-C) levels are often fairly normal in Type 2 diabetes mellitus (DM). We anticipated that a parabolic relation between plasma triglycerides and LDL-C, as previously demonstrated in familial combined hyperlipidaemia (FCHL), might account for this phenomenon. METHODS: Our hypothesis was tested in 1343 subjects derived from the general population who were studied on two occasions 6 years apart (the Hoorn study). Three groups were constructed depending on plasma triglycerides: group A (individuals with both measurements below 1.5 mmol/l), group B (one measurement below and one above 1.5 mmol/l) and group C (both measurements above 1.5 mmol/l). Diabetes status was ascertained by an oral glucose tolerance test. RESULTS: In a mixed linear model, a significant, positive relation between triglycerides and LDL-C was observed for males in group A (beta(a) = 0.5, P < 0.001) and group B (beta(b) = 0.2, P < 0.001), whereas a significant negative relation was found for males in group C (beta(c) = -0.2, P = 0.003). The regression slopes did not differ between diabetic and non-diabetic subjects. Similar results were obtained for women, with the exception that the relation was not significantly negative in group C (beta(c) = -0.1, P = 0.4). CONCLUSION: Plasma triglycerides and LDL-C are related in a parabolic fashion, not only in FCHL, but also in the general population and Type 2 DM. These findings aid our interpretation of typical dyslipidaemia and the effects of treatment that are frequently observed in hypertriglyceridaemic states.

Genetic variation in thioredoxin interacting protein (TXNIP) is associated with hypertriglyceridaemia and blood pressure in diabetes mellitus.

AIMS: Thioredoxin interacting protein (TXNIP) is an attractive candidate gene for diabetes or diabetic dyslipidaemia, since TXNIP is the strongest glucose-responsive gene in pancreatic B-cells, TXNIP deficiency in a mouse model is associated with hyperlipidaemia and TXNIP is located in the 1q21-1q23 chromosomal Type 2 diabetes mellitus (DM) locus. We set out to investigate whether metabolic effects of TXNIP that were previously reported in a murine model are also relevant in human Type 2 DM. METHODS: The frequency distribution of a 3' UTR single nucleotide polymorphism (SNP) in TXNIP was investigated in subjects with normal glucose tolerance (NGT; n = 379), impaired glucose tolerance (IGT; n = 228) and Type 2 DM (n = 230). Metabolic data were used to determine the effect of this SNP on parameters associated with lipid and glucose metabolism. RESULTS: The frequency of the TXNIP variation did not differ between groups, but within the group of diabetic subjects, carriers of the TXNIP-T variant had 1.6-fold higher triglyceride concentrations (P = 0.015; n = 136) and a 5.5-mmHg higher diastolic blood pressure (P = 0.02; n = 212) than homozygous carriers of the common C-allele, whereas in non-diabetic subjects fasting glucose was 0.26 mmol/l lower (P = 0.002; n = 478) in carriers of the T-allele. Moreover, a significant interaction between plasma glucose concentrations and TXNIP polymorphism on plasma triglycerides was observed (P = 0.012; n = 544). CONCLUSION: This is the first report to implicate TXNIP in a human disorder of energy metabolism, Type 2 diabetes. The effect of TXNIP on triglycerides is influenced by plasma glucose concentrations, suggesting that the biological relevance of TXNIP variations may be particularly relevant in recurrent episodes of hyperglycaemia.

Subclasses of low-density lipoprotein and very low-density lipoprotein in familial combined hyperlipidemia: relationship to multiple lipoprotein phenotype.

OBJECTIVE: The present study addresses the presence of distinct metabolic phenotypes in familial combined hyperlipidemia (FCHL) in relation to small dense low-density lipoprotein (sd LDL) and very low-density lipoprotein (VLDL) subclasses. METHODS AND RESULTS: Hyperlipidemic FCHL relatives (n=72) were analyzed for LDL size by gradient gel electrophoresis. Pattern B LDL (sd LDL, particle size <258 A) and pattern A LDL (buoyant LDL, particle size > or =258 A) were defined. Analyses showed bimodal distribution of LDL size associated with distinct phenotypes. Subjects with predominantly large, buoyant LDL showed a hypercholesterolemic phenotype and the highest apo B levels. Subjects with predominantly sd LDL showed a hypertriglyceridemic, low high-density lipoprotein (HDL) cholesterol phenotype, with moderately elevated apoB, total cholesterol level, and LDL cholesterol level. Subjects with both buoyant LDL and sd LDL (pattern AB, n=7) showed an intermediate phenotype, with high normal plasma triglycerides. VLDL subfraction analysis showed that the sd LDL phenotype was associated with a 10-times higher number of VLDL1 particles of relatively lower apo AI and apo E content, as well as smaller VLDL2 particles, in combination with increased plasma insulin concentration in comparison to pattern A. CONCLUSIONS: The present observations underscore the importance of the VLDL triglyceride metabolic pathway in FCHL as an important determinant of the phenotypic heterogeneity of the disorder.