Hypertriglyceridaemic waist phenotype as a simple predictive marker of incident diabetes in Asian-Indian men with prediabetes.

AIM: To determine prospectively the association of baseline hypertriglyceridaemic waist phenotype with incident diabetes in Asian-Indian men with impaired glucose tolerance. METHODS: In a randomized 2-year diabetes prevention trial in 517 men with impaired glucose tolerance, 123 (23.8%) developed diabetes. Baseline anthropometric, metabolic and clinical variables were estimated. Associations of hypertriglyceridaemic waist phenotype (waist circumference ≥ 90cm and a serum triglyceride level of ≥ 1.7 mmol/l) with insulin resistance and incident diabetes were assessed using multiple linear regression and Cox's proportional hazard models, respectively. RESULTS: Men with an isolated enlarged waistline and hypertriglyceridaemic waist phenotype had significantly higher BMI and percentage of total body fat compared with the group with normal waistline and triglyceride levels and the group with isolated hypertriglyceridaemia. The men with hypertriglyceridaemic waist phenotype had higher insulin resistance (mean ± sd homeostasis model assessment of insulin resistance value: 3.6 ± 1.5) compared with those in the isolated enlarged waistline, the isolated hypertriglyceridaemia or the normal waistline and triglyceride level groups (3.1 ± 1.4, 2.7 ± 1.0 and 2.5 ± 1.1, respectively, all P < 0.05 compared with hypertriglyceridaemic waist phenotype). Multiple linear regression analyses showed that hypertriglyceridaemic waist phenotype was significantly associated with insulin resistance after adjusting for age, BMI, family history, percentage of total body fat, smoking, alcohol intake, 2-h plasma glucose and HDL cholesterol level. Hypertriglyceridaemic waist phenotype was independently associated with incident diabetes after adjusting for the above confounders and gamma-glutamyl transferase (hazard ratio 1.49, 95% CI 1.01-2.21; P = 0.047). The association of hypertriglyceridaemic waist phenotype with incident diabetes was abolished when insulin resistance was introduced into the model (hazard ratio 1.39, 95% CI 0.092-2.10; P=0.12). CONCLUSIONS: Hypertriglyceridaemic waist phenotype is a simple clinical proxy measurement for insulin resistance and is strongly associated with incident diabetes in Asian-Indian men with impaired glucose tolerance.

A history of previous gestational diabetes mellitus is associated with adverse changes in insulin secretion and VLDL metabolism independently of increased intrahepatocellular lipid.

AIMS/HYPOTHESIS: We have previously reported a high prevalence of non-alcoholic fatty liver disease (NAFLD) among women with previous gestational diabetes mellitus (pGDM). We wanted to confirm that intrahepatocellular lipid (IHCL) is associated with pGDM independently of adiposity and determine: (1) if VLDL metabolism is dysregulated; and (2) the extent to which NAFLD and IHCL account for the dysmetabolic phenotype in pGDM. METHODS: We analysed data from a cohort of 234 women (114 with pGDM) and identified effects of pGDM on lipid and glucoregulation that were independent of ultrasound-diagnosed NAFLD. We then measured IHCL by MR spectroscopy in a representative subgroup (n = 36) and conducted detailed metabolic studies (IVGTT, VLDL apolipoprotein B [apoB] kinetics and palmitate turnover) and measurement of regional body fat by MRI to demonstrate effects of IHCL that were independent of a history of pGDM. RESULTS: pGDM was associated with increased IHCL (p = 0.04) after adjustment for adiposity. Independently of IHCL, pGDM was associated with a lower IVGTT disposition index (p = 0.02) and acute insulin response to glucose (pGDM+/NAFLD-, 50% lower; pGDM+/NAFLD+, 36% lower; effect of pGDM, p = 0.03), increased VLDL apoB pool size (pGDM+/NAFLD-, 3.1-fold higher; pGDM+/NAFLD+, 1.2-fold higher; effect of pGDM, p = 0.02) and, at borderline significance (p = 0.05), increased rate of VLDL apoB synthesis. CONCLUSIONS/INTERPRETATION: pGDM is associated with increased IHCL independently of adiposity. The increased liver fat contributes to the phenotype, but pGDM status is independently associated with diminished insulin secretion and (shown for the first time) augmented VLDL metabolism. IHCL with pGDM may compound a dysmetabolic phenotype.

Increased prevalence of non-alcoholic fatty liver disease in European women with a history of gestational diabetes.

AIMS/HYPOTHESIS: Non-alcoholic fatty liver disease (NAFLD) is common in type 2 diabetes but it is unknown whether NAFLD is prevalent in European women at risk of type 2 diabetes. We studied the prevalence of, and risk factors for, NAFLD in European women with previous gestational diabetes (GDM) at high risk of type 2 diabetes. METHODS: A total of 110 women with previous GDM and 113 without previous GDM, with non-diabetic glucose tolerance were recruited retrospectively from antenatal databases. Participants underwent liver ultrasound scan examination, anthropometry and blood sampling for liver function tests and to determine levels of fasting lipids, NEFA and insulin and glucose concentrations in order to derive insulin sensitivity and insulin secretion indices (HOMA%S and HOMA%B, respectively). RESULTS: There was no significant difference in BMI in women with previous GDM compared with those without previous GDM (28.9 ± 0.6 vs. 27.9 ± 0.6 kg/m(2), respectively; p = 0.12). Women with previous GDM had higher fasting and 2 h glucose concentrations following a 75 g OGTT ([mean ± SEM] fasting glucose 5.3 ± 0.1 vs. 5.1 ± 0.1 mmol/l, p = 0.02; 2 h glucose 6.8 ± 0.2 vs. 5.8 ± 0.3 mmol/l, p = 0.02), dyslipidaemia (LDL-cholesterol 3.3 ± 0.1 vs. 2.8 ± 0.1 mmol/l; HDL-cholesterol [median {interquartile range}] 1.3 [1.2-1.6] vs. 1.8 [1.5-1.9] mmol/l; triacylglycerol 1.3 [0.9-1.6] vs. 1.0 [0.7-1.7] mmol/l, all p ≤ 0.03), higher insulin secretion and lower insulin sensitivity. NAFLD prevalence was greater in women with previous GDM compared with those without previous GDM: 38% (95% CI 28-47%) vs. 17% (95% CI 10-24%), p = 0.001. In multiple logistic regression analysis, lower insulin sensitivity and raised serum alanine transaminase concentrations were associated with NAFLD. CONCLUSIONS/INTERPRETATION: NAFLD is prevalent in European women with previous GDM. Impaired insulin sensitivity and increased liver transaminase activity are closely associated with NAFLD in these women.

Simple indices of inflammation as predictors of death from cancer or cardiovascular disease in a prospective cohort after two decades of follow-up.

BACKGROUND: Previous studies have identified sub-clinical inflammation as a potential factor in the pathogenesis of cancer and cardiovascular disease (CVD) but the possibility that simple, readily measured indices of sub-clinical inflammation might predict both CVD and cancer has not been tested in the context of a single, prospective analysis. AIM: To evaluate simply measured indices of inflammation as long-term predictors of death from either cancer or CVD. DESIGN: Prospective open cohort study. METHODS: A total of 1192 white males received measurements of a range of risk markers including the inflammation indices white blood cell count (WBC), erythrocyte sedimentation rate (ESR) and serum globulin concentrations. Inflammation marker clustering was quantified as a factor-analysis-derived inflammation score and survival time to death from any cancer or CVD was modeled on baseline measures using the Cox proportional hazards model. RESULTS: A total of 1010 participants met inclusion criteria, of whom 94 died of cancer and 67 of CVD. Mean follow-up times among cases and survivors ranged from 18.2-21.9 years. Independently of established risk factors [age, body mass index (BMI), smoking, alcohol and exercise], WBC, ESR and globulin levels were all individually predictive of both cancer (hazard ratio 1.43, P = 0.002; 1.27, P = 0.02; 1.26, P = 0.02, respectively) and CVD mortality (1.29, P = 0.06; 1.43, P = 0.007; 1.50, P = 0.001). The inflammation score predicted both cancer mortality (1.35, P = 0.003) and CVD mortality (1.46, P = 0.002). Risks associated with high inflammation score were equivalent to and independent of smoking cigarettes for cancer or, for CVD, having a serum cholesterol concentration ≥6.2 mmol/l. CONCLUSIONS: Simple indices of inflammation predict death from cancer or CVD two decades later as strongly as smoking predicts cancer or cholesterol predicts CVD. Their measurement could contribute to evaluation of both cancer and CVD risk.

The effects of rosiglitazone on atherosclerotic progression in patients with Type 2 diabetes at high cardiovascular risk.

AIMS: Cardiovascular mortality remains high despite intensive treatment of people with Type 2 diabetes mellitus. Meta-analyses on rosiglitazone have raised concerns regarding its cardiovascular safety. We studied the effects of rosiglitazone on ultrasonic indices of carotid arterial disease and inflammatory markers in a group of Type 2 diabetic patients at high cardiovascular risk. METHODS: A trial of rosiglitazone in Type 2 diabetic patients with high cardiovascular risk and internal carotid artery plaque compared changes in carotid ultrasound intima-media thickness (IMT), plaque thickness, arterial stiffness and compliance, and inflammatory markers at baseline, 26 and 52 weeks. RESULTS: In the rosiglitazone group (n=28), carotid artery plaque thickness was reduced by 0.08 mm, compared with an increase of 0.19 mm (P=0.075) in the placebo group (n=29). There were no significant differences in changes of IMT, carotid wall compliance and stiffness between the two groups. Glycated haemoglobin reduced by -0.9 vs. 0.1% (-7 vs. 2 mmol/mol), (P<0.001); insulin resistance (HOMA-IR) reduced by -37.6 vs. -1.1% (P=0.016); and B cell function (HOMA-B) increased by 36.8 vs. 0.7% (P=0.009). Non-esterified fatty acids reduced by -23.5 vs. 7.9% (P=0.005); tissue plasminogen activator reduced by -25.0 vs. 0.6% (P=0.001); and plasminogen activator inhibitor activity reduced by -57.4 vs. -34.6% (P=0.052). CONCLUSIONS: Rosiglitazone reduced carotid artery plaque thickness, though not significantly, and there was no significant change in intima media thickness or other ultrasonic indices of carotid arterial disease. There were significant improvements in glycaemic control, insulin sensitivity and fibrinolytic, but not inflammatory, markers. There was no evidence in this study of any adverse effects on progression of carotid arterial disease.

The thermic response to food is related to sensitivity to adrenaline in a group at risk for the development of type II diabetes.

OBJECTIVES: To analyze whether a decreased sensitivity to adrenaline in women with earlier gestational diabetes (GDM) explains the impairment in the thermogenic response to food (=post-prandial thermogenesis (PPT)) that is observed in these women at future risk of obesity and type II diabetes. SUBJECTS/METHODS: Ten normal-weight women with previous GDM and 10 controls matched for body weight, all with normal glucose tolerance, had insulin sensitivity, PPT and the thermogenic response to an adrenaline infusion measured. RESULTS: Insulin sensitivity was similar in the previous GDM compared with control groups: (mean+/-s.e.m.) 29.1+/-3.2 vs 30.9+/-1.6 mg/l/min. The early (0-30 min) PPT response was diminished and delayed in women with previous GDM compared with controls: (10+/-2 vs 15+/-1 kJ, P=0.04); time constant for PPT (median (interquartile range)) (57 (47-79) vs 29 (25-49) min, P=0.01). The overall PPT response and the thermogenic response to adrenaline were not significantly different between the groups. The 30 min and 2 h PPT response correlated positively and significantly with the increment in energy expenditure as a result of the adrenaline infusion (rho=+0.65; P=0.04 and rho=+0.71; P=0.02, respectively) in women with previous GDM only. There was no correlation between adrenaline and insulin sensitivity. CONCLUSIONS: There is no evidence of diminished adrenaline sensitivity but a positive relationship exists between PPT and sensitivity to adrenaline in women with previous GDM. The mechanism is not mediated through insulin resistance. This relationship may predispose these normal-weight at-risk women to future weight gain.

Glucose sensors: a review of current and emerging technology.

Glucose monitoring technology has been used in the management of diabetes for three decades. Traditional devices use enzymatic methods to measure glucose concentration and provide point sample information. More recently continuous glucose monitoring devices have become available providing more detailed data on glucose excursions. In future applications the continuous glucose sensor may become a critical component of the closed loop insulin delivery system and, as such, must be selective, rapid, predictable and acceptable for continuous patient use. Many potential sensing modalities are being pursued including optical and transdermal techniques. This review aims to summarize existing technology, the methods for assessing glucose sensing devices and provide an overview of emergent sensing modalities.

A randomised interventional trial of omega-3-polyunsaturated fatty acids on endothelial function and disease activity in systemic lupus erythematosus.

OBJECTIVE: To determine the clinical effect of dietary supplementation with low-dose omega-3-polyunsaturated fatty acids on disease activity and endothelial function in patients with systemic lupus erythematosus. METHODS: A 24-week randomised double-blind placebo-controlled parallel trial of the effect of 3 g of omega-3-polyunsaturated fatty acids on 60 patients with systemic lupus erythematosus was performed. Serial measurements of disease activity using the revised Systemic Lupus Activity Measure (SLAM-R) and British Isles Lupus Assessment Group index of disease activity for systemic lupus erythematosus (BILAG), endothelial function using flow-mediated dilation (FMD) of the brachial artery, oxidative stress using platelet 8-isoprostanes and analysis of platelet membrane fatty acids were taken at baseline, 12 and 24 weeks. RESULTS: In the fish oil group there was a significant improvement at 24 weeks in SLAM-R (from 9.4 (SD 3.0) to 6.3 (2.5), p<0.001); in BILAG (from 13.6 (6.0) to 6.7 (3.8), p<0.001); in FMD (from 3.0% (-0.5 to 8.2) to 8.9% (1.3 to 16.9), p<0.001) and in platelet 8-isoprostanes (from 177 pg/mg protein (23-387) to 90 pg/mg protein (32-182), p = 0.007). CONCLUSIONS: Low-dose dietary supplementation with omega-3 fish oils in systemic lupus erythematosus not only has a therapeutic effect on disease activity but also improves endothelial function and reduces oxidative stress and may therefore confer cardiovascular benefits.

Long-term changes and variability in diabetes risk factors prior to the development of impaired glucose homeostasis.

AIMS: To determine whether rate of change and variability in risk factors provides insight into the development of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or Type 2 diabetes (DM). METHODS: In a nested case-control study, repeated risk factor measurements (mean number 4.3, duration 11.4 years) culminated in 59 men developing IFG (n = 37), IGT (n = 14) and/or DM (n = 11). For each case, two control subjects were matched for age and equivalence of follow-up. Rates of change and variability in diabetes risk factors prior to diagnosis were quantified by regression analysis. Changes between penultimate and diagnostic visits were also analysed. RESULTS: The age-related rise in body mass index (BMI) was attenuated prior to IFG compared with control subjects (+0.102 vs. +0.772 kg/m2/decade, P = 0.02). There was also some evidence for this prior to IGT and DM (IGT: -1.530 vs. +0.158 kg/m2/decade, P = 0.09; DM: -1.146 vs. +0.332 kg/m2/decade, non-significant). Prior to onset, IGT cases were distinguished by higher inflammatory marker levels, a decline in insulinogenic index and greater variability in oral glucose tolerance test (OGTT) insulin, and DM cases by lower insulin sensitivity and higher liver enzyme activities. Fasting and OGTT glucose levels changed little during the mean 8.9 years prior to onset of IFG, IGT or DM. The transition to IGT or DM was accompanied by a fall in insulin sensitivity. CONCLUSIONS: Except for BMI, change or variability in risk factor levels appears relatively unimportant in the development of clinically elevated glucose levels. Deterioration in glucose levels to IGT or DM occurs as a rapid, incremental increase accompanied by a decline in insulin sensitivity.

The UK Diabetes Research Network--an opportunity and a challenge.

The Department of Health has funded a national diabetes network to support clinical research. The network will facilitate recruitment into clinical trials and has been widely welcomed by clinicians. However, if the network is to reach its full potential, all those involved will need to advocate a change in attitude towards clinical trials and research, encouraging participation and contribution of data. Clinicians need to be willing to take a proactive view about research studies, and to encourage patients to adopt a positive and altruistic attitude towards trial participation. The future of trials and other important clinical research in the UK may depend on it.

Glucose production in the human placenta.

Glucose transfer from mother to fetus by placental facilitated diffusion is the dominant mechanism by which the fetus acquires glucose. In small for gestational age pregnancies, fetal glucose concentrations tend to be lower than normal and this persists following delivery. GLUT1 is the major glucose transporter in human placenta but there is no evidence of GLUT1 deficiency as a cause of the lower fetal glucose concentration in small for gestational age pregnancy. The physiological and pathological roles of the other glucose transporters (and there are 14 currently described) are unknown. In recent years, the possibility has been raised that the placenta is itself capable of supplying glucose for fetal needs. This hypothesis derived from glucose isotope studies in normal pregnancy, where dilution of glucose isotope was demonstrated in blood samples taken from the fetal circulation during intravenous infusion of glucose isotope in the mother. Although other gluconeogenic enzymes were known to be present, the placenta was previously considered incapable of glucose secretion because it lacked functional glucose-6-phosphatase. Recent studies, however, have suggested that specific glucose-6-phosphatase may be present in placenta but it may be the product of a different gene from conventional hepatic glucose-6-phosphatase. The presence of the specific transporters necessary for glucose-6-phosphatase activity is currently being investigated. The role of placental glucose secretion in normal and growth-restricted pregnancies is an area of current study.

The impact of ethnicity on glucose regulation and the metabolic syndrome following gestational diabetes.

AIMS/HYPOTHESIS: We assessed the impact of ethnic origin on metabolism in women following gestational diabetes mellitus (GDM). MATERIALS AND METHODS: Glucose regulation and other features of the metabolic syndrome were studied at 20.0 (18.2-22.1) months (geometric mean [95% CI]) post-partum in women with previous GDM (185 European, 103 Asian-Indian, 80 African-Caribbean). They were compared with the same features in 482 normal control subjects who had normal glucose regulation during and following pregnancy. RESULTS: Impaired glucose regulation or diabetes by WHO criteria were present in 37% of women with previous GDM (diabetes in 17%), especially in those of African-Caribbean and Asian-Indian origin (50 and 44%, respectively vs 28% in European, p=0.009). BMI, waist circumference, diastolic blood pressure, fasting triglyceride and insulin levels, and insulin resistance by homeostatic model assessment (HOMA), were increased following GDM (p<0.001 for all, vs control subjects). Where glucose regulation was normal following GDM, basal insulin secretion (by HOMA) was high (p<0.001 vs control subjects). Irrespective of glucose regulation in pregnancy, Asian-Indian origin was associated with high triglyceride and low HDL cholesterol levels, and African-Caribbean with increased waist circumference, blood pressure, and insulin levels, together with insulin resistance and low triglyceride concentrations. Nonetheless, the GDM-associated features were consistent within each ethnic group. The metabolic syndrome by International Diabetes Federation criteria was present in 37% of women with previous GDM, especially in non-Europeans (Asian-Indian 49%, African-Caribbean 43%, European 28%, p=0.001), and in 10% of controls. CONCLUSIONS/INTERPRETATION: Following GDM, abnormal glucose regulation and the metabolic syndrome are common, especially in non-European women, indicating a need for diabetes and cardiovascular disease prevention strategies.

Metabolic syndrome and coronary heart disease in South Asians, African-Caribbeans and white Europeans: a UK population-based cross-sectional study.

AIMS/HYPOTHESIS: The aim of this study was to study differences in the prevalence of the metabolic syndrome and its associations with prevalent CHD according to ethnicity and sex. METHODS: We performed a combined analysis of two population-based cross-sectional studies conducted between 1988 and 1991 that followed identical protocols. Participants (aged 40-69 years) comprised 2,346 Europeans (76% male), 1,711 South Asians (83% male) and 803 African-Caribbeans (57% male) resident in west London. Fasting blood, overnight urine collection, clinical and anthropometric measurements were performed. Clinical history or major ECG changes defined prevalent CHD. The metabolic syndrome was defined according to the criteria recommended by the World Health Organization (WHO) and the National Cholesterol Education Programme (NCEP). RESULTS: The prevalence of the metabolic syndrome was highest in South Asians (WHO, men 46%, women 31%; NCEP, men 29%, women 32%) and lowest in European women (WHO, 9%; NCEP, 14%). The prevalence of CHD was 10% in South Asian men, 9% in European men, 5-6% in African-Caribbeans and European women, and 2% in South Asian women. The metabolic syndrome was associated with prevalent CHD in European men [NCEP, odds ratio (OR)=1.6, 95% CI 1.2-2.4; WHO, OR=1.7, 95% CI 1.2-2.5] and South Asian men (NCEP, OR=2.1, 95% CI 1.5-3.1; WHO, OR=1.6, 95% CI 1.1-2.3). Associations with CHD were weaker in African-Caribbeans and were inconsistent among European women. CONCLUSIONS/INTERPRETATION: The current definitions of the metabolic syndrome give an inconsistent picture of cardiovascular disease risk when applied to different ethnic groups within the UK. Prospective studies are needed to validate workable ethnic-specific definitions.

Vitamin D deficiency masking primary hyperparathyroidism.

Vitamin D deficiency and primary hyperparathyroidism (PHPT) are relatively common disorders. The coexistence of these conditions should be considered, as depletion of vitamin D may alter the clinical expression of autonomous parathyroid disease. We report details of a vitamin D deficient patient in whom replacement therapy led to the unmasking of occult PHPT.

Loss of beta cell function as fasting glucose increases in the non-diabetic range.

AIMS/HYPOTHESIS: Our aim was to define the level of glycaemia at which pancreatic insulin secretion, particularly first-phase insulin release, begins to decline. METHODS: Plasma glucose and insulin concentrations were measured during an IVGTT in 553 men with non-diabetic fasting plasma glucose concentrations. In 466 of the men C-peptide was also estimated. IVGTT insulin secretion in first and late phases was assessed by: (i) the circulating insulin response; (ii) population parameter deconvolution analysis of plasma C-peptide concentrations; and (iii) a combined model utilising both insulin and C-peptide concentrations. Measurements of insulin sensitivity and elimination were also derived by modelling analysis. RESULTS: As fasting plasma glucose (FPG) increased, IVGTT first-phase insulin secretion declined by 73%, 71% and 68% for the three methods respectively. The FPG values at which this decline began, determined by change point regression, were 4.97, 5.16 and 5.42 mmol/l respectively. The sensitivity of late-phase insulin secretion to glucose declined at FPG concentrations above 6.0 mmol/l. Insulin elimination, but not insulin sensitivity, varied with FPG. CONCLUSIONS/INTERPRETATION: The range of FPG over which progressive loss of the first-phase response begins may be as low as 5.0 to 5.4 mmol/l, with late-phase insulin responses declining at FPG concentrations above 6.0 mmol/l.

Metabolic effects of Troglitazone in patients with diet-controlled type 2 diabetes.

BACKGROUND: In order to study the mechanisms of action of Troglitazone (TGZ) in vivo in Type 2 diabetes, its effects were studied on glucose metabolism, lipolysis and very low-density lipoprotein (VLDL) apolipoprotein B100 (apoB) kinetics. MATERIALS AND METHODS: A placebo-controlled, double-blind study was performed in 24 diet-treated patients randomized to receive TGZ 600 mg day(-1), TGZ 200 mg day(-1) or placebo for 8 weeks. Glucose and glycerol turnover were assessed after an overnight fast, and during sequential low-dose insulin infusions (0.01 U kg(-1) h(-1) followed by 0.015 U kg(-1) h(-1)) using 6,6-2H Glucose and 1,2,3-2H Glycerol. Very low-density lipoprotein apoB secretion was measured using l-13C-leucine, monitoring isotopic enrichment by gas chromatography-mass spectrometry. Treatment effects were analyzed by analysis of covariance, adjusting for baseline. RESULTS: Therapy resulted in a significant group differences in fasting plasma glucose adjusting for baseline (P=0.039). This was most evident at TGZ 600 mg daily [glucose decrease from (mean +/- SD) 9.2 +/- 2.7 to 6.6 +/- 0.9 mmol L(-1)]. HbA1c and insulin levels did not change significantly. Plasma nonesterified fatty acid (NEFA) levels decreased (P=0.045), most evidently at TGZ 200 mg daily, but glycerol was not significantly affected. Although no significant effects were observed on VLDL apoB or triglyceride concentrations, there were treatment differences in the absolute secretion rate of VLDL apoB of borderline (P=0.056) statistical significance, with a decrease observed at TGZ 600 mg daily [geometric mean, SD range, 0.94 (0.41-2.15) to 0.40 (0.14-1.13 mg kg(-1) h(-1))]. Very low-density lipoprotein apoB fractional secretion rate and pool size were unaffected. The VLDL triglyceride: apoB molar ratio differed between treatment groups (P=0.013), being higher in the TGZ 600 mg group [5714 (4128-7741) to 8092 (5669-11552)]. Neither glucose nor glycerol rates of appearance were significantly altered by TGZ and nor did TGZ affect their suppression by insulin. DISCUSSION: The PPARgamma agonist, troglitazone, decreases fasting glucose and NEFA levels in diet-treated Type 2 diabetes. It may also decrease VLDL particle secretion. These effects would be considered beneficial. The biological importance of the increase in VLDL-triglyceride enrichment warrants further study.

Leukocyte ABCA1 gene expression is associated with fasting glucose concentration in normoglycemic men.

Adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1) mediates the efflux of cholesterol to apolipoprotein A1, a process necessary for high-density lipoprotein (HDL) formation and reverse cholesterol transport. In patients with Tangier disease, mutations in ABCA1 result in low circulating HDL-cholesterol and predisposition to coronary heart disease (CHD). ABCA1 gene expression is decreased in diabetic mice. In humans, glycated hemoglobin (HbA(1c)) predicted future CHD events, even within the normal range. We hypothesised that leukocyte ABCA1 gene expression would be inversely associated with indices of glycemia in normoglycemic men. Fasting blood samples were taken from 32 healthy, nonsmoking, normoglycemic men (age 23 to 46 years). ABCA1, peroxisome proliferator-activated receptor gamma (PPARgamma), and liver X receptor alpha (LXRalpha) gene expressions in circulating leukocytes were measured using TaqMan technology. Significant inverse associations between ABCA1 gene expression and both fasting glucose concentration (r = -0.49, P =.008) and age (r = -0.39, P =.043) were found. There was no association with HbA(1c) (r = -0.23, P =.238) or HDL-cholesterol concentration (r = 0.02, P =.904). In a multiple regression model, fasting glucose remained a significant independent predictor (P =.037), whereas age did not (P =.226). Mechanisms underlying the association were explored; there were no significant associations between fasting glucose concentration and leukocyte PPARgamma gene expression, or between fasting glucose concentration and leukocyte LXRalpha gene expression. This is the first demonstration of an association between ABCA1 gene expression and fasting glucose concentration in vivo.

Analysis of the contribution to type 2 diabetes susceptibility of sequence variation in the gene encoding stearoyl-CoA desaturase, a key regulator of lipid and carbohydrate metabolism.

AIMS/HYPOTHESIS: Stearoyl-CoA desaturase (SCD) is emerging as a key regulator of lipid and carbohydrate metabolism. Scd-null mice display a beneficial metabolic phenotype characterised by resistance to obesity, diabetes and hyperlipidaemia. The human homologue, SCD, maps to a region of chromosome 10 linked to type 2 diabetes, and SCD activity correlates with insulin sensitivity. Given this strong positional and biological candidacy, the present study sought to establish whether sequence variation in SCD influences susceptibility to type 2 diabetes and related traits. METHODS: The SCD gene was resequenced in 23 diabetic subjects. Six variants within coding and adjacent sequence, including a non-synonymous SNP in exon 5 (M224L), were selected for genotyping in a primary set of 608 diabetic subjects and 600 control subjects. RESULTS: There was no association (at the allele, genotype or haplotype level) with type 2 diabetes, although genotype frequencies at the +14301 A>C SNP in the 3' untranslated region showed borderline association (p~0.06) when evidence for linkage was taken into account. However, replication studies (350 young-onset diabetic patients; 747 controls) failed to confirm any relationship with diabetes for this variant. No significant associations were seen for diabetes-related traits including BMI and waist-to-hip ratio. CONCLUSIONS/INTERPRETATION: The present study, the first reported analysis of this gene, indicates that the SCD variants typed do not explain chromosome-10-encoded susceptibility to type 2 diabetes. Although this study provided no evidence that SCD sequence variation influences diabetes susceptibility or related traits, SCD remains a major target for pharmaceutical and/or environmental manipulation.

Semi quantitative expression analysis of MDR3, FIC1, BSEP, OATP-A, OATP-C,OATP-D, OATP-E and NTCP gene transcripts in 1st and 3rd trimester human placenta.

Using real time RT-PCR, we have detected expression of seven genes that influence bile acid transport,MDR3, FIC1, BSEP, OATP-A, OATP-C, OATP-D and OATP-E, in normal human placenta. With the exception of OATP-C and OATP-E these genes were found to be differentially expressed in 1st trimester and 3rd trimester placentae. MDR3 gene expression was found to be up regulated four fold in 3rd trimester placentae compared to 1st trimester, OATP-A gene expression was down regulated eight fold, OATP-D was down regulated 17 fold, while FIC1 expression was reduced by 33 fold in the 3rd trimester. OATP-C and BSEP gene expression was not detected in the 3rd trimester placenta, while low levels of transcripts were detected in the 1st trimester placentae. Transcripts of the hepatic sinusoidal bile acid transporter, NTCP, were not detected in placenta.