Using proximity extension proteomics assay to discover novel biomarkers associated with circulating leptin levels in patients with type 2 diabetes.

We aimed to discover novel associations between leptin and circulating proteins which could link leptin to the development of cardiovascular disease in patients with type 2 diabetes (T2DM). In a discovery phase, we investigated associations between 88 plasma proteins, assessed with a proximity extension assay, and plasma leptin in a cohort of middle-aged patients with T2DM. Associations passing the significance threshold of a False discovery rate of 5% (corresponding to p < 0.0017) were replicated in patients with T2DM in an independent cohort. We also investigated if proteins mediated the longitudinal association between plasma leptin and the incidence of major cardiovascular events (MACE). One protein, adipocyte fatty acid binding protein (A-FABP), was significantly associated with leptin in both the discovery phase [95% CI (0.06, 0.17) p = 0.00002] and the replication cohort [95% CI (0.12, 0.39) p = 0.0003]. Multiplicative interaction analyses in the two cohorts suggest a stronger association between A-FABP and leptin in men than in women. In longitudinal analyses, the association between leptin and MACE was slightly attenuated after adding A-FABP to the multivariate model. Our analysis identified a consistent association between leptin and A-FABP in two independent cohorts of patients with T2DM, particularly in men.Trial registration: ClinicalTrials.gov identifier NCT01049737.

Treatment of road runoff by coagulation/flocculation and sedimentation.

A laboratory investigation of the treatment potential of a coagulation process in the context of stormwater treatment was undertaken. The initial 25 L road runoff generated from four rain events was collected and subjected to a jar-testing regime with two commercial coagulants. The treatment effect was assessed by analysing the runoff before and after treatment for turbidity, suspended solids and metal content. The coagulation process resulted in particle and total metal reduction of more than 90% compared to 40% for only sedimentation. Up to 40% reduction of dissolved Cr, Cu and Pb was also observed compared to 0% for sedimentation. This study shows that coagulation may be a useful process for stormwater treatment systems when the treatment requirements are high.

The impact of using sagittal abdominal diameter to predict major cardiovascular events in European patients with type 2 diabetes.

BACKGROUND AND AIMS: Obesity is associated with diabetes type 2 and one of the most important risk factors for cardiovascular disease. We explored if sagittal abdominal diameter (SAD) is a better predictor of major cardiovascular events than waist circumference (WC) and body mass index (BMI) in type 2 diabetes. METHODS AND RESULTS: The CARDIPP study consists of a cohort of patients with type 2 diabetes. In this study we used data from 635 participants with no previous myocardial infarction or stroke, with a mean follow-up time of 7.1 years. SAD, WC and BMI were measured at baseline and the end-point was first cardiovascular event, measured as a composite of ICD-10 codes for acute myocardial infarction, stroke or cardiovascular mortality. SAD was significantly higher in the major cardiovascular event group compared to participants that did not suffer a major cardiovascular event during follow-up (p < 0.001). SAD >25 cm was the only anthropometric measurement that remained associated with major cardiovascular events when adjusted for modifiable and non-modifiable factors (hazard ratio 2.81, 95% confidence interval 1.37-5.76, p = 0.005). CONCLUSION: SAD with the cut off level of >25 cm, if confirmed in larger studies, may be used as a more independent risk-assessment tool compared with WC in clinical practice, to identify persons with type 2 diabetes at high cardiovascular risk. ClinicalTrials.gov: NCT01049737.

Association between serum 25(OH)D3 and cardiovascular morbidity and mortality in people with Type 2 diabetes: a community-based cohort study.

AIM: We aimed to explore the association between vitamin D and cardiovascular morbidity and mortality in people with Type 2 diabetes recruited from a community-based study because there is limited and inconsistent research of this group. METHODS: A prospective community-based cohort study among people aged 55-66 years with Type 2 diabetes as part of The Cardiovascular Risk in Type 2 Diabetes - A Prospective Study in Primary Care (CARDIPP). We analysed serum 25-hydroxyvitamin D3 [25(OH)D3 ] at baseline. Cox regression analyses were used to calculate hazard ratios (HR) for the first myocardial infarction, stroke or cardiovascular mortality according to 25(OH)D3 . RESULTS: We examined 698 people with a mean follow-up of 7.3 years. Serum 25(OH)D3 was inversely associated with the risk of cardiovascular morbidity and mortality: HR 0.98 [95% confidence interval (CI) 0.96 to 0.99, P = 0.001]. Compared with the fourth quartile (Q4) [25(OH)D3 > 61.8 nmol/l], HR (with 95% CI) was 3.46 (1.60 to 7.47) in Q1 [25(OH)D3 < 35.5 nmol/l] (P = 0.002); 2.26 (1.01 to 5.06) in Q2 [25(OH)D3 35.5-47.5 nmol/l] (P = 0.047); and 1.62 (0.70 to 3.76) in Q3 [25(OH)D3 47.5-61.8 nmol/l] (P = 0.26) when adjusting for age, sex and season. The results remained significant after adjusting also for cardiovascular risk factors, physiological variables including parathyroid hormone and previous cardiovascular disease (P = 0.027). CONCLUSIONS: Low 25(OH)D3 is associated with an increased risk of cardiovascular morbidity and mortality in people with Type 2 diabetes independent of parathyroid hormone. Vitamin D could be considered as a prognostic factor. Future studies are needed to explore whether vitamin D deficiency is a modifiable risk factor in Type 2 diabetes.

The association between endostatin and kidney disease and mortality in patients with type 2 diabetes.

AIM: Circulating endostatin, a biologically active derivate of collagen XVIII, is considered to be a marker of kidney disease and a risk factor for its related mortality. However, less is known of the role of endostatin in diabetes and the development of diabetic nephropathy. For this reason, our study investigated the associations between circulating endostatin and the prevalence and progression of kidney disease, and its mortality risk in patients with type 2 diabetes (T2D). METHODS: This was a cohort study of 607 patients with T2D (mean age: 61 years, 44% women). Estimated glomerular filtration rate (eGFR), calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation, was used to assess the patients' kidney function decline and mortality. RESULTS: Of the total study cohort, 20 patients declined by ≥20% in eGFR over 4 years, and 44 died during the follow-up (mean duration: 6.7 years). At baseline, participants with diabetic nephropathy (defined as eGFR<60mL/min/1.73m2) and/or microalbuminuria [defined as a urinary albumin-to-creatinine ratio (ACR)>3g/mol] had higher median levels of endostatin than those without nephropathy (62.7µg/L vs 57.4µg/L, respectively; P=0.031). In longitudinal analyses adjusted for age, gender, baseline eGFR and ACR, higher endostatin levels were associated with a higher risk of decline (≥20% in eGFR, OR per 1 SD increase: 1.73, 95% CI: 1.13-2.65) and a higher risk of mortality (HR per 1 SD increase: 1.57, 95% CI: 1.19-2.07). CONCLUSION: In patients with T2D, circulating endostatin levels can predict the progression of kidney disease and mortality independently of established kidney disease markers. The clinical usefulness of endostatin as a risk marker in such patients merits further studies.

Pedometer-determined physical activity level and change in arterial stiffness in Type 2 diabetes over 4 years.

AIM: To explore prospectively the correlation between the level of pedometer-determined physical activity at the start of the study and the change in pulse wave velocity from baseline to 4 years later in people with Type 2 diabetes. METHODS: We analysed data from 135 men and 53 women with Type 2 diabetes, aged 54-66 years. Physical activity was measured with waist-mounted pedometers on 3 consecutive days and the numbers of steps/day at baseline were classified into four groups: <5000 steps/day, 5000-7499 steps/day, 7500-9999 steps/day and ≥10 000 steps/day. Pulse wave velocity was measured using applanation tonometry over the carotid and femoral arteries at baseline and after 4 years. RESULTS: The mean (±sd; range) number of steps/day was 8022 (±3765; 956-20 921). The participants with the lowest level of physical activity had a more pronounced increase in the change in pulse wave velocity compared with the participants with the highest. When change in pulse wave velocity was analysed as a continuous variable and adjusted for sex, age, diabetes duration, HbA1c , BMI, systolic blood pressure, pulse wave velocity at baseline, ß-blocker use, statin use, unemployment, smoking and diabetes medication, the number of steps/day at baseline was significantly associated with a less steep increase in change in pulse wave velocity (P=0.005). Every 1000 extra steps at baseline corresponded to a lower increase in change in pulse wave velocity of 0.103 m/s. CONCLUSIONS: We found that a high level of pedometer-determined physical activity was associated with a slower progression of arterial stiffness over 4 years in middle-aged people with Type 2 diabetes.

Randomization to a low-carbohydrate diet advice improves health related quality of life compared with a low-fat diet at similar weight-loss in Type 2 diabetes mellitus.

AIMS: To compare the effects on health-related quality of life (HRQoL) of a 2-year intervention with a low-fat diet (LFD) or a low-carbohydrate diet (LCD) based on four group-meetings to achieve compliance. To describe different aspects of taking part in the intervention following the LFD or LCD. METHODS: Prospective, randomized trial of 61 adults with Type 2 diabetes mellitus. The SF-36 questionnaire was used at baseline, 6, 12 and 24 months. Patients on LFD aimed for 55-60 energy percent (E%) and those on LCD for 20 E% from carbohydrates. The patients were interviewed about their experiences of the intervention. RESULTS: Mean body-mass-index was 32.7 ± 5.4 kg/m(2) at baseline. Weight-loss did not differ between groups and was maximal at 6 months, LFD: -3.99 ± 4.1 kg, LCD: -4.31 ± 3.6 kg (p<0.001 within groups). There was an increase in the physical component score of SF-36 from 44.1 (10.0) to 46.7 (10.5) at 12 months in the LCD group (p < 0.009) while no change occurred in the LFD group (p < 0.03 between groups). At 12 months the physical function, bodily pain and general health scores improved within the LCD group (p values 0.042-0.009) while there was no change within the LFD group. CONCLUSIONS: Weight-changes did not differ between the diet groups while improvements in HRQoL only occurred after one year during treatment with LCD. No changes of HRQoL occurred in the LFD group in spite of a similar reduction in body weight.

Microalbuminuria, but not reduced eGFR, is associated with cardiovascular subclinical organ damage in type 2 diabetes.

AIM: This study explored the association between reduced estimated glomerular filtration rate (eGFR) and microalbuminuria vs. subclinical organ damage in patients with type 2 diabetes. METHODS: Data from middle-aged patients with type 2 diabetes (n=706) treated in primary care were analyzed for microalbuminura, defined as a urinary albumin/creatinine ratio (uACR)≥3.0mmol/mol, and reduced eGFR, defined as<60mL/min/1.73m(2), in relation to blood pressure, pulse wave velocity (PWV), left ventricular mass index (LVMI), and carotid intima-media thickness (IMT) and lumen diameter (LD). RESULTS: Patients with microalbuminuria had significantly higher 24-h ambulatory systolic blood pressure (ASBP) compared with subjects with uACR<3mg/mmol: 137 vs. 128mmHg (P<0.001). There were no differences in ASBP in patients with eGFR<60mL/min/1.73m(2). However, patients with vs. without microalbuminuria had increased PWV (11.4 vs. 10.1m/s; P<0.001), LVMI (134.4 vs. 118.6g/m(2); P<0.001), LD (7.01±0.93 vs. 6.46±0.74mm; P<0.001) and IMT (0.78 vs. 0.74mm; P=0.047), respectively. The associations between uACR vs. PWV and LVMI were more robust after adjusting for age, diabetes duration, ASBP, HbA1c, LDL-cholesterol, and antihypertensive and lipid-lowering therapy compared with uACR vs. IMT. There were no statistically significant differences in PWV, LVMI or IMT between patients with reduced (<60mL/min/1.73m(2)) vs. normal eGFR. CONCLUSION: Levels of urinary albumin excretion, but not reduced eGFR, were associated with increased arterial stiffness, left ventricular mass and atherosclerosis in patients with type 2 diabetes.

Abdominal obesity and low-grade systemic inflammation as markers of subclinical organ damage in type 2 diabetes.

AIM: This study aimed to explore the associations between abdominal obesity, inflammatory markers and subclinical organ damage in 740 middle-aged patients with type 2 diabetes. METHODS: Waist circumference (WC) and sagittal abdominal diameter (SAD) were measured, and blood samples were analyzed for C-reactive protein (CRP) and IL-6. Carotid intima-media thickness (IMT) was evaluated by ultrasonography, and aortic pulse wave velocity (PWV) measured with applanation tonometry. RESULTS: Abdominal obesity as determined by SAD and WC was significantly correlated with IL-6 (WC: r=0.27, P<0.001; SAD: r=031, P<0.001), CRP (WC: r=0.29, P<0.001; SAD: r=0.29, P<0.001), IMT (WC: r=0.09, P=0.013; SAD: r=0.11, P=0.003) and PWV (WC: r=0.18, P<0.001; SAD: r=0.21, P<0.001). In multiple linear regressions with IMT and PWV as dependent variables, and age, gender, statin use, systolic blood pressure (SBP), body mass index (BMI), CRP and HbA1c as independent variables, both SAD and WC remained associated with IMT and PWV. On stepwise linear regression and entering both SAD and WC, the association between SAD and PWV was stronger than the association between WC and PWV. CONCLUSION: Both SAD and WC are feasible measures of obesity, and both provide information on inflammation, atherosclerosis and arterial stiffness in type 2 diabetes, while SAD appears to be slightly more robustly associated with subclinical organ damage than WC.

In type 2 diabetes, randomisation to advice to follow a low-carbohydrate diet transiently improves glycaemic control compared with advice to follow a low-fat diet producing a similar weight loss.

AIMS/HYPOTHESIS: The study aimed to compare the effects of a 2 year intervention with a low-fat diet (LFD) or a low-carbohydrate diet (LCD), based on four group meetings to achieve compliance. METHODS: This was a prospective randomised parallel trial involving 61 adults with type 2 diabetes consecutively recruited in primary care and randomised by drawing ballots. Patients that did not speak Swedish could not be recruited. The primary outcomes in this non-blinded study were weight and HbA(1c). Patients on the LFD aimed for 55-60 energy per cent (E%) and those on LCD for 20 E% from carbohydrate. RESULTS: The mean BMI and HbA(1c) of the participants were 32.7 ± 5.4 kg/m(2) and 57.0 ± 9.2 mmol/mol, respectively. No patients were lost to follow-up. Weight loss did not differ between groups and was maximal at 6 months: LFD -3.99 ± 4.1 kg (n=31); LCD -4.31 ± 3.6 kg (n=30); p < 0.001 within groups. At 24 months, patients on the LFD had lost -2.97 ± 4.9 kg and those on LCD -2.34 ± 5.1 kg compared with baseline (p = 0.002 and p = 0.020 within groups, respectively). HbA(1c) fell in the LCD group only (LCD at 6 months -4.8 ± 8.3 mmol/mol, p = 0.004, at 12 months -2.2 ± 7.7 mmol/mol, p = 0.12; LFD at 6 months -0.9 ± 8.8 mmol/mol, p = 0.56). At 6 months, HDL-cholesterol had increased with the LCD (from 1.13 ± 0.33 mmol/l to 1.25 ± 0.47 mmol/l, p = 0.018) while LDL-cholesterol did not differ between groups. Insulin doses were reduced in the LCD group (0 months, LCD 42 ± 65 E, LFD 39 ± 51 E; 6 months, LCD 30 ± 47 E, LFD 38 ± 48 E; p = 0.046 for between-group change). CONCLUSIONS/INTERPRETATION: Weight changes did not differ between the diet groups, while insulin doses were reduced significantly more with the LCD at 6 months, when compliance was good. Thus, aiming for 20% of energy intake from carbohydrates is safe with respect to cardiovascular risk compared with the traditional LFD and this approach could constitute a treatment alternative. TRIAL REGISTRATION: ClinicalTrials.gov NCT01005498 FUNDING: University Hospital of Linköping Research Funds, Linköping University, the County Council of Östergötland, and the Diabetes Research Centre of Linköping University.

Pedometer-determined physical activity is linked to low systemic inflammation and low arterial stiffness in Type 2 diabetes.

AIMS: The aim of this study was to explore the association between pedometer-determined physical activity versus measures of obesity, inflammatory markers and arterial stiffness in people with Type 2 diabetes. METHODS: We analysed data from 224 men and 103 women with Type 2 diabetes, aged 54-66 years. Physical activity was measured with waist-mounted pedometers during three consecutive days and the number of steps/day were calculated and classified in four groups: < 5000 steps/day, 5000-7499 steps/day, 7500-9999 steps/day and ≥ 10000 steps/day. Blood samples were analysed for lipids, HbA(1c), inflammatory markers including C-reactive protein and interleukin-6. Nurses measured blood pressure and anthropometrics. Aortic pulse wave velocity was measured with applanation tonometry over the carotid and femoral arteries. RESULTS: Mean steps/day was 7683 ± 3883 (median 7222, interquartile range 4869-10,343). There were no differences in age, diabetes duration, blood pressure, lipids or glycaemic control between the four groups of pedometer-determined physical activity. Subjects with higher steps/day had lower BMI (28.8 vs. 31.5 kg/m(2), P < 0.001), waist circumference (101.7 vs. 108.0 cm, P < 0.001), lower levels of C-reactive protein (1.6 vs. 2.6 mg/l, P = 0.007), lower levels of interleukin-6 (1.9 vs. 3.8 pg ml, P < 0.001) and lower pulse wave velocity (10.2 vs. 11.0 m/s, P = 0.009) compared with less physically active people. CONCLUSIONS: We conclude that physical activity measured with pedometer was associated not only with less abdominal obesity, but also with decreased systemic low-grade inflammation as well as with low arterial stiffness, in people with Type 2 diabetes.

Carotid intima-media thickness and apolipoprotein B/apolipoprotein A-I ratio in middle-aged patients with Type 2 diabetes.

AIMS: To explore the association between carotid intima-media thickness (IMT) and the apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) ratio compared with conventional lipids in middle-aged patients with Type 2 diabetes. METHODS: We analysed data from 247 patients with Type 2 diabetes, aged 55-66 years, in the Cardiovascular Risk factors in Patients with Diabetes-a Prospective study in Primary care (CARDIPP-1) study. Primary care nurses measured blood pressure and anthropometric characteristics. Blood samples were taken for laboratory analyses. The carotid IMT was determined by ultrasonography at the University Hospital in Linköping and at the County Hospital Ryhov, Jönköping, Sweden. RESULTS: The ApoB/apoA-I ratio (r = 0.207, P = 0.001), apoB (r = 0.166, P = 0.009) and non-high-density lipoprotein cholesterol (non-HDL-c) (r = 0.129, P = 0.046) correlated with IMT. Conventional lipids, high-sensitivity C-reactive protein (hsCRP), glycated haemoglobin (HbA(1c)) and systolic blood pressure were not significantly correlated to IMT. A stepwise logistic regression analysis was conducted with IMT as the dependent variable and the apoB/apoA-I ratio, HbA(1c), hsCRP, low-density lipoprotein cholesterol (LDL-c), total cholesterol, non-HDL-c and treatment with statins as independent variables. Following adjustment for age and gender, only the apoB/apoA-I ratio remained significantly associated with IMT (odds ratio 4.3, 95% confidence intervals 1.7-10.8, P = 0.002). CONCLUSIONS: We conclude that there was a significant association between the apoB/apoA-I ratio and IMT in middle-aged patients with Type 2 diabetes. The association was independent of conventional lipids, hsCRP, glycaemic control and use of statins.

Masked nocturnal hypertension--a novel marker of risk in type 2 diabetes.

AIMS/HYPOTHESIS: This study was designed to evaluate the prevalence of masked nocturnal hypertension (MNHT) and its impact on arterial stiffness and central blood pressure in patients with type 2 diabetes. METHODS: Middle-aged patients (n = 414) with type 2 diabetes underwent clinic and ambulatory BP measurements and applanation tonometry. RESULTS: MNHT (clinic BP < 130/80 mmHg and night-time BP > or = 120/70 mmHg) was found in 7.2% of patients (n = 30). Compared with patients with both clinical and nocturnal normotension (n = 70), patients with MNHT had higher aortic pulse wave velocity (PWV) (10.2 +/- 1.8 m/s vs 9.4 +/- 1.7 m/s; p = 0.03) and higher central BP (117.6 +/- 13.9/74.0 +/- 9.1 mmHg vs 110.4 +/- 16.4/69.7 +/- 9.6 mmHg, p = 0.04). In patients with clinical normotension, night-time systolic BP correlated significantly with PWV. CONCLUSIONS/INTERPRETATION: Thirty per cent of patients with clinical normotension had nocturnal hypertension. This was accompanied by increased arterial stiffness and higher central BP. We conclude that in clinically normotensive patients with type 2 diabetes, ambulatory BP measurement may help clinicians to identify patients with increased cardiovascular risk.

Fluid therapy and the use of albumin in the treatment of severe traumatic brain injury.

BACKGROUND: Evidence-based guidelines for severe traumatic brain injury (TBI) do not include strategies for fluid administration. The protocol used in this study includes albumin administration to maintain normal colloid osmotic pressure and advocates a neutral to slightly negative fluid balance. The aim of this study was to analyze the occurrence of organ failure and the mortality in patients with severe TBI treated by a protocol that includes defined strategies for fluid therapy. METHODS: Ninety-three patients with severe TBI and Glasgow Coma Score or=3 was evident only for respiratory failure, which was observed in 29%. None developed renal failure. After 28 days, mortality was 11% and, after 18 months, it was 14%. CONCLUSIONS: A protocol including albumin administration in combination with a neutral to a slightly negative fluid balance was associated with low mortality in patients with severe TBI in spite of a relatively high frequency (29%) of respiratory failure, assessed with the SOFA score.

Fast-food-based hyper-alimentation can induce rapid and profound elevation of serum alanine aminotransferase in healthy subjects.

OBJECTIVE: To study the effect of fast-food-based hyper-alimentation on liver enzymes and hepatic triglyceride content (HTGC). DESIGN: Prospective interventional study with parallel control group. SETTING: University Hospital of Linköping, Sweden. PARTICIPANTS: 12 healthy men and six healthy women with a mean (SD) age of 26 (6.6) years and a matched control group. INTERVENTION: Subjects in the intervention group aimed for a body weight increase of 5-15% by eating at least two fast-food-based meals a day with the goal to double the regular caloric intake in combination with adoption of a sedentary lifestyle for 4 weeks. MAIN OUTCOME MEASURES: Weekly changes of serum aminotransferases and HTGC measured by proton nuclear magnetic resonance spectroscopy at baseline and after the intervention. RESULTS: Subjects in the intervention group increased from 67.6 (9.1) kg to 74.0 (11) kg in weight (p<0.001). Serum ALT increased from 22.1 (11.4) U/l at study start to an individual mean maximum level of 97 (103) U/l (range 19.4-447 U/l). Eleven of the 18 subjects persistently showed ALT above reference limits (women >19 U/l, men >30 U/l) during the intervention. Sugar (mono- and disaccharides) intake during week 3 correlated with the maximal ALT/baseline ALT ratio (r = 0.62, p = 0.006). HTGC increased from 1.1 (1.9)% to 2.8 (4.8)%, although this was not related to the increase in ALT levels. ALT levels were unchanged in controls. CONCLUSION: Hyper-alimentation per se can induce profound ALT elevations in less than 4 weeks. Our study clearly shows that in the evaluation of subjects with elevated ALT the medical history should include not only questions about alcohol intake but also explore whether recent excessive food intake has occurred.

Weight gain restriction for obese pregnant women: a case-control intervention study.

OBJECTIVE: To minimise obese women's total weight gain during pregnancy to less than 7 kg and to investigate the delivery and neonatal outcome. DESIGN: A prospective case-control intervention study. SETTING: Antenatal care clinics in the southeast region of Sweden. POPULATION: One hundred fifty-five pregnant women in an index group and one hundred ninety-three women in a control group. METHODS: An intervention programme with weekly motivational talks and aqua aerobic classes for obese pregnant women. MAIN OUTCOME MEASURES: Weight gain in kilograms, delivery and neonatal outcome. RESULTS: The index group had a significantly lower weight gain during pregnancy compared with the control group (P < 0.001). The women in the index group weighed less at the postnatal check-up compared with the weight registered in early pregnancy (P < 0.001). The percentage of women in the index group who gained less than 7 kg was greater than that of women in the control group who gained less than 7 kg (P= 0.003). The percentage of nulliparous women in this group was greater than that in the control group (P= 0.018). In addition, the women in the index group had a significantly lower body mass index at the postnatal check-up, compared with the control group (P < 0.001). There were no differences between the index group and the control group regarding birthweight, gestational age and mode of delivery. CONCLUSION: The intervention programme was effective in controlling weight gain during pregnancy and did not affect delivery or neonatal outcome.

Insulin-induced GLUT4 translocation to the plasma membrane is blunted in large compared with small primary fat cells isolated from the same individual.

AIMS/HYPOTHESIS: Several studies have suggested that large fat cells are less responsive to insulin than small fat cells. However, in these studies, large fat cells from obese individuals were compared with smaller fat cells from leaner participants, in effect making it impossible to draw conclusions about whether there is a causal relationship between fat cell size and insulin sensitivity. We hypothesised that small fat cells might be more insulin-responsive than large adipocytes when obtained from the same individual. MATERIALS AND METHODS: We developed a method of sorting isolated primary human fat cells by using nylon filters of two different pore sizes. The cells were stained to visualise DNA, which allowed discrimination from artefacts such as lipid droplets. The sorted cells were left to recover overnight, since we had previously demonstrated that this is necessary for correct assessment of insulin response. RESULTS: We found similar amounts of the insulin receptor (IR), IRS-1 and GLUT4 when we compared small and large adipocytes from the same volunteer by immunoblotting experiments using the same total cell volume from both cell populations. Activation of IR, IRS-1 and Akt1 (also known as protein kinase B) by insulin was similar in the two cell populations. However, immunofluorescence confocal microscopy of plasma membrane sheets did not reveal any increase in the amount of GLUT4 in the plasma membrane following insulin stimulation in the large fat cells, whereas we saw a twofold increase in the amount of GLUT4 in the small fat cells. CONCLUSIONS/INTERPRETATION: Our results support a causal relationship between the accumulation of large fat cells in obese individuals and reduced insulin responsiveness.

Peroxisome proliferator activated receptor gamma activity is low in mature primary human visceral adipocytes.

AIMS/HYPOTHESIS: The amount of visceral fat mass strongly relates to insulin resistance in humans. The transcription factor peroxisome proliferator activated receptor gamma (PPARG) is abundant in adipocytes and regulates genes of importance for insulin sensitivity. Our objective was to study PPARG activity in human visceral and subcutaneous adipocytes and to compare this with the most common model for human disease, the mouse. MATERIALS AND METHODS: We transfected primary human adipocytes with a plasmid encoding firefly luciferase controlled by PPARG response element (PPRE) from the acyl-CoA-oxidase gene and measured PPRE activity by emission of light. RESULTS: We found that PPRE activity was 6.6-fold higher (median) in adipocytes from subcutaneous than from omental fat from the same subjects (n = 23). The activity was also 6.2-fold higher in subcutaneous than in intra-abdominal fat cells when we used a PPARG ligand-binding domain-GAL4 fusion protein as reporter, demonstrating that the difference in PPRE activity was due to different levels of activity of the PPARG receptor in the two fat depots. Stimulation with 5 micromol/l rosiglitazone did not induce a PPRE activity in visceral adipocytes that was as high as basal levels in subcutaneous adipocytes. Interestingly, in mice of two different strains the PPRE activity was similar in visceral and subcutaneous fat cells. CONCLUSIONS/INTERPRETATION: We found considerably lower PPARG activity in visceral than in subcutaneous primary human adipocytes. Further studies of the molecular mechanisms behind this difference could lead to development of drugs that target the adverse effects of visceral obesity.

Nurse-recorded clinic and ambulatory blood pressures correlate equally well with left ventricular mass and carotid intima-media thickness.

OBJECTIVE: To assess relationships between noninvasive ambulatory blood pressure (BP), clinic BP (mean value of three readings in the seated position measured by nurses), structural cardiac indices, intima-media thickness of the common carotid artery and several hormones. DESIGN: Cross-sectional study of 75 subjects with hypertension and left ventricular hypertrophy (HTH) according to echocardiography, 35 subjects with hypertension and normal left ventricular dimensions (HT) and 23 normotensive subjects (NT). RESULTS: We found an excellent correlation between mean 24-h ambulatory BP and clinic BP, the r-value for systolic BP being 0.82 and for diastolic levels 0.78 (both P < 0.0001). Clinic and ambulatory BP correlated equally well with left ventricular (LV) mass index (r-values between 0.55 and 0.64, all P < 0.0001) and to intima-media thickness of the carotid artery (r = 0.18-0.34, P < 0.01). The systolic white-coat effect (clinic BP - day-time BP) was higher in the HTH and HT compared with NT and was weakly correlated to LV mass index (r = 0.18, P = 0.04). Nondippers (mean arterial night/day BP ratio of > 0.9) had higher brain (6.1 +/- 7.5 pmol L(-1) vs. 3.7 +/- 3.2 pmol L(-1), P = 0.01) and atrial (14 +/- 3.4 pmol L(-1) vs. 9.3 +/- 5.4 pmol L(-1), P = 0.04) natriuretic peptide levels, and also exhibited a lower ejection fraction (49 +/- 8% vs. 57 +/- 9%, P = 0.006), than dippers. CONCLUSION: Clinic BP recordings performed by nurses as three measurements 1 min apart provide excellent relationship to target organ damage. Nondippers exhibited signs of a more advanced hypertensive organ damage than dippers which corresponds well with the poor prognosis linked to this condition.

Beta1-adrenergic receptor gene polymorphisms and response to beta1-adrenergic receptor blockade in patients with essential hypertension.

BACKGROUND: Studies suggest that the Ser49Gly and Arg389Gly polymorphisms in the beta1-adrenergic receptor might be of functional importance for the cardiovascular system. Both have been associated with altered receptor activity in vitro, and with hypertension and cardiac failure in vivo. HYPOTHESIS: The aim of this study was to test whether these polymorphisms were associated with the change in heart rate or blood pressure in patients with essential hypertension and left ventricular (LV) hypertrophy treated with the beta1-adrenergic receptor blocker atenolol. METHODS: Blood pressure and heart rate were measured in 101 hypertensive patients with echocardiographically verified LV hypertrophy, randomized in a double-blind study to treatment with either the beta1-adrenergic receptor blocker atenolol or the angiotensin II type I receptor antagonist irbesartan. Changes in blood pressure and heart rate were evaluated after 12 weeks. Beta1-adrenergic receptor genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism. RESULTS: We found no significant associations between the changes in the measured variables and either of the two polymorphisms. However, carriers of the 49Gly allele showed a tendency toward a greater reduction in heart rate compared with patients with the Ser/Ser49 genotype (p = 0.06). CONCLUSIONS: The Ser49Gly and Arg389Gly beta1-adrenergic receptor polymorphisms do not seem to exert a major effect on the changes in heart rate and blood pressure during 12 weeks of treatment with atenolol in patients with essential hypertension and LV hypertrophy.