Effects of phlebotomy-induced reduction of body iron stores on metabolic syndrome: results from a randomized clinical trial

BACKGROUND

Metabolic syndrome (METS) is an increasingly prevalent but poorly understood clinical condition characterized by insulin resistance, glucose intolerance, dyslipidemia, hypertension, and obesity. Increased oxidative stress catalyzed by accumulation of iron in excess of physiologic requirements has been implicated in the pathogenesis of METS, but the relationships between cause and effect remain uncertain. We tested the hypothesis that phlebotomy-induced reduction of body iron stores would alter the clinical presentation of METS, using a randomized trial.

METHODS

In a randomized, controlled, single-blind clinical trial, 64 patients with METS were randomly assigned to iron reduction by phlebotomy (n = 33) or to a control group (n = 31), which was offered phlebotomy at the end of the study (waiting-list design). The iron-reduction patients had 300 ml of blood removed at entry and between 250 and 500 ml removed after 4 weeks, depending on ferritin levels at study entry. Primary outcomes were change in systolic blood pressure (SBP) and insulin sensitivity as measured by Homeostatic Model Assessment (HOMA) index after 6 weeks. Secondary outcomes included HbA1c, plasma glucose, blood lipids, and heart rate (HR).

RESULTS

SBP decreased from 148.5 ± 12.3 mmHg to 130.5 ± 11.8 mmHg in the phlebotomy group, and from 144.7 ± 14.4 mmHg to 143.8 ± 11.9 mmHg in the control group (difference -16.6 mmHg; 95% CI -20.7 to -12.5; P < 0.001). No significant effect on HOMA index was seen. With regard to secondary outcomes, blood glucose, HbA1c, low-density lipoprotein/high-density lipoprotein ratio, and HR were significantly decreased by phlebotomy. Changes in BP and HOMA index correlated with ferritin reduction.

CONCLUSIONS

In patients with METS, phlebotomy, with consecutive reduction of body iron stores, lowered BP and resulted in improvements in markers of cardiovascular risk and glycemic control. Blood donation may have beneficial effects for blood donors with METS.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01328210 Please see related article: http://www.biomedcentral.com/1741-7015/10/53.

Salivary cortisol as a diagnostic tool for Cushing's syndrome and adrenal insufficiency: improved screening by an automatic immunoassay

BACKGROUND

Salivary cortisol is increasingly used to assess patients with suspected hypo- and hypercortisolism. This study established disease-specific reference ranges for an automated electrochemiluminescence immunoassay (ECLIA).

METHODS

Unstimulated saliva from 62 patients with hypothalamic-pituitary disease was collected at 0800 h. A peak serum cortisol level below 500 nmol/l during the insulin tolerance test (ITT) was used to identify hypocortisolism. Receiver-operating characteristic (ROC) analysis allowed establishment of lower and upper cutoffs with at least 95% specificity for adrenal insufficiency and adrenal sufficiency. Saliva from 40 patients with confirmed hypercortisolism, 45 patients with various adrenal masses, and 115 healthy subjects was sampled at 2300 h and after low-dose dexamethasone suppression at 0800 h . ROC analysis was used to calculate thresholds with at least 95% sensitivity for hypercortisolism. Salivary cortisol was measured with an automated ECLIA.

RESULTS

When screening for secondary adrenal insufficiency, a lower cutoff of 3.2 nmol/l and an upper cutoff of 13.2 nmol/l for unstimulated salivary cortisol allowed a highly specific diagnosis (i.e. similar to the ITT result) in 26% of patients. For identification of hypercortisolism, cutoffs of 6.1 nmol/l (sensitivity 95%, specificity 91%, area under the curve (AUC) 0.97) and 2.0 nmol/l (sensitivity 97%, specificity 86%, AUC 0.97) were established for salivary cortisol at 2300 h and for dexamethasone-suppressed salivary cortisol at 0800 h.

CONCLUSIONS

The newly established thresholds facilitated initial screening for secondary adrenal insufficiency and allowed excellent identification of hypercortisolism. Measurement by an automated immunoassay will allow broader use of salivary cortisol as a diagnostic tool.

Assay-Abhängigkeit der Calcitonin- Zielbereiche für „biochemisch geheilte“ Patienten mit medullärem Schilddrüsenkarzinom

Aim: Calcitonin (hCT) is an important diagnostic parameter in medullary thyroid carcinoma (MTC). We determined the variability of the reference ranges of several currently available immunometric assays for „biochemically cured“ MTC patients. Patients, methods: We compared six assays [Nichols ICMA, Biomerica IEMA, Immulite 2000 (Siemens), Calcitonin-IRMA magnum (Medipan), SELco-IRMA (Medipan) and Calcitonin IRMA (Medgenix)] in subgroups of 198 patients with differentiated thyroid cancer (DTC) after total thyroidectomy as a model for curatively treated MTC patients. In addition, hCT was measured after pentagastrin stimulation in 13 DTC patients and 13 patients with MTC. Results: The basal hCT concentrations were below the detection limit of the respective assay in 100% of all thyroidectomized DTC patients for Nichols ICMA (n = 138) and Immulite 2000 (n = 60), in 97% for Biomerica IEMA (n = 57), and in 85% for IRMA magnum (n = 20). However, basal hCT was mostly within the reference range in Selco-IRMA (n = 20) and Medgenix IRMA (n = 76). In all DTC patients and 9/13 MTC patients the pentagastrin stimulated hCT was below the detection limit for the Nichols ICMA and Immulite 2000, all four MTC patients with elevated stimulated hCT developed a recurrence during follow-up. Conclusions: For assays with high monomer specificity (Nichols ICMA, Biomerica IEMA, Immulite 2000, to a lesser degree IRMA magnum) biochemical cure is defined by basal and stimulated calcitonin levels below the detection limit. For assays with low monomer specificity (SELco-IRMA, IRMA Medgenix) calcitonin levels in the reference range of patients without thyroid diseases are consistent with “biochemical cure”.

Measurement of urinary free cortisol by current immunoassays: need for sex-dependent reference ranges to define hypercortisolism

Urinary free cortisol (UFC) is used to assess disease activity in hypercortisolemic patients. However, reference ranges are often lacking, especially with respect to potential confounding variables. This study analyzed upper limits of normal (ULN, mean + 2 SD) for 2 newer immunoassays, using gas chromatography-mass spectrometry (GC-MS) as reference method. Each 10 healthy subjects were grouped by age (18-29; 30-49; ≥ 50 years), BMI (< 25; ≥ 25 kg/m2), and sex, resulting in a total of 120 controls (60 males; age: 39.3±1.3 years; BMI: 25.9±0.4 kg/m2). ULN were calculated for a radioimmunoassay (RIA, Immunotech) and an electrochemiluminescence immunoassay (ECLIA, Roche) and applied to 12 hypercortisolemic patients (4 males; age: 53.1±3.1 years; BMI: 29.1±1.8 kg/m2). To determine degradation, samples were stored at 4°C (without light) or 22°C (with and without light) for 0, 24, and 72 h. Cortisol concentrations were significantly correlated: r=0.88 for RIA vs. ECLIA, r=0.75 for RIA vs. GC-MS, and r=0.77 for ECLIA vs. GC-MS (always p<0.0001). For each procedure, multiple stepwise regression analysis identified sex as the only significant predictor, resulting in sex-dependent ULN (males vs. females): 294 vs. 208 nmol/24 h (RIA), and 379 vs. 277 nmol/24 h (ECLIA). These ULN classified samples from patients as hypercortisolemic in 100% (RIA) and 95% (ECLIA). Different storage conditions over 72 h did not alter UFC levels significantly. Results of the 3 procedures were well correlated, and the use of assay- and sex-specific ULN allowed excellent identification of hypercortisolic states. UFC is stable over 72 h irrespective of the storage conditions applied.

Calcitonin substitution in calcitonin deficiency reduces particle-induced osteolysis

Background

Periprosthetic osteolysis is a major cause of aseptic loosening in joint arthroplasty. This study investigates the impact of CT (calcitonin) deficiency and CT substitution under in-vivo circumstances on particle-induced osteolysis in Calca -/- mice.

Methods

We used the murine calvarial osteolysis model based on ultra-high molecular weight polyethylene (UHMWPE) particles in 10 C57BL/6J wild-type (WT) mice and twenty Calca -/- mice. The mice were divided into six groups: WT without UHMWPE particles (Group 1), WT with UHMWPE particles (Group 2), Calca -/- mice without UHMWPE particles (Group 3), Calca -/- mice with UHMWPE particles (Group 4), Calca -/- mice without UHMWPE particles and calcitonin substitution (Group 5), and Calca -/- mice with UHMWPE particle implantation and calcitonin substitution (Group 6). Analytes were extracted from serum and urine. Bone resorption was measured by bone histomorphometry. The number of osteoclasts was determined by counting the tartrate-resistant acid phosphatase (TRACP) + cells.

Results

Bone resorption was significantly increased in Calca -/- mice compared with their corresponding WT. The eroded surface in Calca -/- mice with particle implantation was reduced by 20.6% after CT substitution. Osteoclast numbers were significantly increased in Calca -/- mice after particle implantation. Serum OPG (osteoprotegerin) increased significantly after CT substitution.

Conclusions

As anticipated, Calca -/- mice show extensive osteolysis compared with wild-type mice, and CT substitution reduces particle-induced osteolysis.

Transcriptional regulation by nonclassical action of thyroid hormone

Abstract

Thyroid hormone (TH) is essential for normal development, growth and metabolism. Its effects were thought to be principally mediated through triiodothyronine (T3), acting as a ligand for the nuclear TH receptors (TRs) α and β residing on thyroid hormone response elements (TREs) in the promoter of TH target genes. In this classical model of TH action, T3 binding to TRs leads to recruitment of basal transcription factors and increased transcription of TH responsive genes.

Recently, the concept of TH action on gene expression has become more diverse and now includes nonclassical actions of T3 and T4: T3 has been shown to activate PI3K via the TRs, which ultimately increases transcription of certain genes, e.g. HIF-1α. Additionally, both T3 and thyroxine (T4) can bind to a membrane integrin, αvβ3, which leads to activation of the PI3K and MAPK signal transduction pathways and finally also increases gene transcription, e.g. of the FGF2 gene. Therefore, these initially nongenomic, nonclassical actions seem to serve as additional interfaces for transcriptional regulation by TH. Aim of this perspective is to summarize the genes that are currently known to be induced by nonclassical TH action and the mechanisms involved.

Biochemical markers of particle induced osteolysis in C57BL/6 mice

BACKGROUND

Micro-structural changes associated with ultra high molecular weight polyethylene particle (UHMWPE) induced osteolysis, the most frequent cause of aseptic loosening, have been intensively investigated in the mammalian calvarian model by histomorphometry and micro-computed tomography. However, little is known regarding the serological changes that occur during this process.

METHODS

Serological parameters for bone metabolism [calcium, phosphate, osteocalcin (OCN), deoxypyridinoline (DPD)/creatinine, alkaline phosphatase, osteoprotegerin and receptor activator of nuclear factor-κB] were analyzed in this animal model for particle induced osteolysis. Ten C57BL/6 mice were divided at random into sham operated and UHM-WPE implanted groups. Blood and urine samples were collected prior to and at 14 days after surgery.

RESULTS

Implantation of UHMWPE lead to a significant decrease in bone volume (p=0.027). Both groups (sham/UHMWPE) showed a significant increase in calcium (p=0.004/p=0.027) and phosphate (p=0.001/p=0.001), without correlation to particle implantation. Significantly higher concentrations of DPD/creatinine (p=0.034) and OCN (p=0.022) were found after implantation of UHM-WPE. In addition, parameters could not be correlated to particle induced osteolysis.

CONCLUSIONS

DPD can be regarded as a valuable parameter for detecting UHMWPE induced osteolysis in the calvarian model. Further studies of serum parameters should focus on the clinical relevance in aseptic prosthetic loosening.

Influence of various confounding variables and storage conditions on metanephrine and normetanephrine levels in plasma

OBJECTIVE

Measurements of plasma free metanephrines have been advocated as first-line tests for phaeochromocytoma. The aim of the study was to assess the impact of potential confounding variables.

DESIGN

Comparative study between 2008 and 2009.

SUBJECTS

Hundred and eighty healthy subjects.

MEASUREMENTS

The effects of age, BMI, gender, menstrual cycle (sampling every 2 days), time of day (sampling every 2 h), venepunture (0, 15, 30, 60, 90 and 120 min), physical exercise (0, 15 and 30 min), coffee (0 and 60 min), breakfast (0 and 60 min) and various body positions (standing and supine rest, each 0 and 120 min) were evaluated. In addition, whole blood and plasma samples were stored at 4 degrees C or at 22 degrees C for 0, 1, 3, 24 and 72 h. Plasma free metanephrines were measured using radioimmunoassay (LDN).

RESULTS

While metanephrine was significantly influenced by sex and age, BMI and sex were significant predictors of normetanephrine. Coffee (+20%) and food (+8%) elevated normetanephrine significantly (P < 0.05), while metanephrine remained stable. Physical exercise increased metanephrine (+82%) as well as normetanephrine (+84%) significantly (P < 0.005). Supine rest significantly decreased both metanephrine (-34%) and normetanephrine (-19%) when compared to standing rest (P < 0.01). Metanephrine and normetanephrine were not significantly influenced by time of day, menstrual cycle or venepuncture. When plasma samples were stored at 4 degrees C, metanephrine and normetanephrine were stable for 72 h.

CONCLUSIONS

Physical exercise may lead to relevant changes in metanephrine and normetanephrine and should therefore be avoided prior to sampling. Although effects of age, sex and BMI were small, these variables should be considered when interpreting biochemical results. Blood should be taken in the supine position, and samples should be immediately centrifuged and stored at 4 degrees C to improve stability.

Clinical value of the first automated TSH receptor autoantibody assay for the diagnosis of Graves' disease (GD): an international multicentre trial

BACKGROUND

Most recently, a new rapid and fully automated electrochemiluminescence immunoassay for the determination of TSH receptor autoantibodies (TRAb) based on the ability of TRAb to inhibit the binding of a human thyroid-stimulating monoclonal antibody (M22) has been established.

OBJECTIVE

To evaluate this assay system in clinical routine based on an international multicentre trial and to compare the results with other established TRAb assays.

PATIENTS AND MEASUREMENTS

Totally 508 Graves' disease (GD), 142 autoimmune thyroiditis, 107 subacute thyroiditis, 109 nonautoimmune nodular goitre, 23 thyroid cancer patients and 446 normal controls were retrospectively evaluated.

RESULTS

ROC plot analysis revealed an area under curve of 0.99 (95% CI: 0.99-1.0) indicating a high assay sensitivity and specificity. The highest sensitivity (99%) and specificity (99%) was seen at a cut-off level of 1.75 IU/l. Here, the calculated positive predictive value was 95%, whereas the negative predictive value was 100%. Applying the ROC plot-derived cut-off of 1.75 IU/l we found a sensitivity for TRAb positivity within the group of newly diagnosed GD patients of 97% which is in accordance to the sum of different nonautomated porcine TSH receptor-based assays with a sensitivity of 94% indicating an excellent analytical performance of the new assay format. Detailed comparison of the automated and the sum of manual assays revealed a near identical specificity.

CONCLUSION

Our results demonstrate that this new assay system has a high sensitivity for detecting GD and specificity for discriminating from other thyroid diseases. This assay may represent the future technology for rapid fully automated TRAb detection.

Prevalence of anterior pituitary dysfunction in patients following traumatic brain injury in a German multi-centre screening program

INTRODUCTION

We determined the prevalence of anterior pituitary dysfunction in a multi-centre screening program across five German endocrine centres in patients rehabilitating from TBI (GCS<13).

PATIENTS & METHODS

246 patients (39+/-14 yrs; 133 males, 12+/-8 months after TBI) underwent a series of baseline endocrine tests with central assessment of TSH, free T4, prolactin, LH, FSH, testosterone (m), estradiol (f), cortisol, GH, and IGF-I. If IGF-I was <-2 SDS dynamic testing was performed. GHD was defined according to BMI-dependent cut-off values for GH response to GHRH+arginine of <4.2, <8.0 and <11.5 ng/ml in obese, overweight and lean subjects, respectively, or <3 micro g/l in ITT. Hypocortisolism was suggested when basal cortisol was <200 nmol/l and confirmed by ITT (peak<500 nmol/l).

RESULTS

In TBI patients some degree of impaired pituitary function was shown in 21% (n=52/246). Total, multiple and isolated deficits were present in 1%, 2% and 18%, respectively. 19% had an IGF-I of <-1 SDS, 9% of <-2 SDS. In 5% GHD was confirmed. 9% had hypogonadism. 4% had hypocortisolism and 1% of patients had confirmed ACTH-deficiency. 12% had TSH-deficiency.

SUMMARY

In summary, in this large series carried out on an unselected group of TBI survivors we have found hypopituitarism in every fifth patient with predominantly secondary hypogonadism and hypothyreosis. Regarding somatotrope insufficiency IGF-I is decreased in 50% of GHD patients.

CONCLUSION

These findings strongly suggest that patients who suffer head trauma should routinely undergo endocrine evaluation.

The role of leptin and cortisol in hyperactivity in patients with acute and weight-recovered anorexia nervosa

INTRODUCTION

In food-restricted rats, leptin as well as corticotropin releasing factor attenuate semistarvation-induced hyperactivity (SIH). Results from studies in patients with anorexia nervosa (AN) showed an association between excessive physical activity (PA) and leptin. One recent report suggests a role for cortisol in PA. In this study, we assessed the relationships between PA and both, cortisol and leptin levels at the same time in patients with acute anorexia nervosa (acAN) in comparison to recovered patients (recAN).

METHODS

Plasma leptin, plasma cortisol, body mass index (BMI), and expert-ratings of qualities of PA were assessed in 36 acAN patients, 27 recAN patients and 44 healthy control woman (HCW). Regression analyses were used to predict PA using BMI, leptin and cortisol levels as predictor variables.

RESULTS

Leptin levels but not cortisol significantly contributed to the prediction of PA in acAN. In recAN PA was not elevated and not related to endocrine parameters but correlated positively with core eating disorder symptoms.

CONCLUSIONS

Our work lends support to the proposed inverse association between peripheral leptin levels and excessive physical activity in AN. This relationship is specific to the state of semistarvation. The role of additional mediators remains to be clarified.

Association of impaired fasting glucose and coronary artery calcification as a marker of subclinical atherosclerosis in a population-based cohort--results of the Heinz Nixdorf Recall Study

AIMS/HYPOTHESIS

Atherosclerosis and cardiovascular diseases are often present at the time of diagnosis of type 2 diabetes mellitus. Whether subclinical atherosclerosis can be detected in the pre-diabetic (borderline fasting hyperglycemia) state is not clear. This study investigated the association of impaired fasting glucose (IFG) and coronary artery calcification (CAC), a marker of subclinical atherosclerosis, among participants without a history of coronary heart disease or manifest diabetes mellitus.

METHODS

Study participants (aged 45-75 years) of the population-based Heinz Nixdorf Recall Study were categorised into those with normal fasting glucose (glucose <6.1 mmol/l) and those with IFG (glucose >or=6.1 to <7.0 mmol/l), excluding participants with a history of CHD or diabetes mellitus. CAC was assessed by electron-beam computed tomography, and risk factors were assessed by extended interviews, anthropometric measurements and laboratory tests. Various CAC cut-off points were used in multiple logistic and ordinal logistic regression models to estimate ORs and 95% CIs.

RESULTS

Of the 2,184 participants, more men had IFG than did women (37% vs 22%). Participants with IFG showed a higher prevalence of CAC > 0 (men OR 1.90, 95% CI 1.33-2.70; women 1.63, 1.23-2.15). Risk factor adjustment weakened this association in both sexes (men 1.63, 1.12-1.36; women 1.26, 0.93-1.70). When the age- and sex-specific 75th percentile was used as the cut-off point for CAC, the association further decreased in men (1.10, 0.81-1.50), but became stronger in women (1.41, 1.02-1.94).

CONCLUSIONS/INTERPRETATION

These data support the hypothesis that CAC is already present in the pre-diabetic state and that IFG has a modest and independent impact on the atherosclerotic process. Biological sex appears to modify the association between IFG and CAC.

Technical evaluation of the first fully automated assay for the detection of TSH receptor autoantibodies

BACKGROUND

Graves' disease (GD) is mediated by autoantibodies which bind to the TSH receptor (TRAb). The aim of the present study was to evaluate the technical performance of the first fully automated immunoassay for TRAb detection.

METHODS

The Elecsys Anti-TSHR immunoassay utilizes a porcine TSH receptor (TSHR) and the human thyroid stimulating monoclonal TSHR autoantibody M22.

RESULTS

Intraassay and total imprecision CV were determined between 1.4%-14.9%, and 2.4%-28.8%, respectively. Using the 20% CV criteria the functional sensitivity was found at 0.73 IU/L. The median CV at the cut-off (1.75 IU/L) was found to be 11%. Comparison studies with five TRAb immunoassays yielded slopes and intercepts between 1.02-1.48, and -0.74-0.56, respectively. Correlation coefficients were determined between 0.895 and 0.978. ROC plot analysis of patients with GD, patients with other thyroid disorders and healthy controls revealed an AUC of 0.99 resulting in a sensitivity of 97% and a specificity of 99% at a TRAb level of 1.75 IU/L.

CONCLUSION

The evaluation of the TRAb immunoassay generated homogeneous performance data and demonstrated a high degree of comparability to established TRAb assays. The automated TRAb assay represents a major improvement of thyroid testing in clinical practice.

Are symptoms of depression more common in diabetes? Results from the Heinz Nixdorf Recall study

AIMS

To estimate the association between depressive symptoms and Type 2 diabetes, as well as previously undetected diabetes, in a large population-based sample in Germany and to determine associated variables.

METHODS

We used baseline data on 4595 participants (age 45-75 years, 50.2% women) from the German Heinz Nixdorf Recall study, a population-based, prospective cohort study which started in 2000. Diabetes mellitus was assessed by self report (physician diagnosis or medication), undiagnosed diabetes based on blood glucose levels. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale short form (cut-off >or= 15 points). We fitted multiple logistic regression models.

RESULTS

The prevalence of diagnosed and previously undetected diabetes was 9.3% (95% confidence interval 8.2-11.6) and 7.6% (6.6-8.8) in men and 6.0% (5.1-7.1) and 3.2% (2.5-4.0) in women, respectively. Compared with non-diabetic women, the prevalence of depressive symptoms was not significantly different in diabetic women (age-adjusted odds ratio, 95% confidence interval 1.48; 0.98-2.24) and women with undiagnosed diabetes (0.67; 0.33-1.36). In men, the prevalence of depressive symptoms tended to be lower in diabetic than in non-diabetic subjects (0.62; 0.35-1.09), but the depressive symptoms were significantly less frequent in men with undiagnosed diabetes (0.30; 0.13-0.70). The pattern remained after further adjustment. Significant associations with depressive symptoms were found for co-morbidities and living without a partner in both women and in men, and for body mass index and activity level in women only.

CONCLUSIONS

After adjustment for relevant covariates, the association between depressive symptoms and Type 2 diabetes was heterogenous in our population-based study. In subjects with undiagnosed diabetes, however, depressive symptoms were less frequent in men. Co-morbidities and psychosocial conditions are strongly associated with depressive symptoms.

Expression and mutation analysis of the tyrosine kinase c-kit in poorly differentiated and anaplastic thyroid carcinoma

Poorly differentiated and anaplastic thyroid carcinoma are aggressive tumors failing to res-pond to conventional therapy. Imatinib mesylate offers an effective therapeutic option in patients with various types of malignancies by inhibiting tyrosine kinases such as c-kit. In this study we investigated c-kit expression in anaplastic and poorly differentiated thyroid carcinoma compared to differentiated carcinoma and adenoma and the presence of c-kit mutations. In total, 224 thyroid tissues were analyzed by immunohistochemistry. Mutation analysis of exon 9, 11, 13, and 17 of the c-kit gene was performed in anaplastic and poorly differentiated carcinoma. c-Kit expression was negative in all anaplastic thyroid carcinoma, while c-kit expression of poorly differentiated carcinoma showed a high variability with a more intense staining in tumors showing obvious differentiated malignant follicular tumor areas. Differentiated carcinoma showed a slight, but not significantly stronger c-kit expression than poorly differentiated carcinoma. All tumors revealed wild type sequences of c-kit gene in exons 9, 11, 13, and 17. The low or lacking c-kit expression in undifferentiated thyroid carcinoma together with the lack of mutations argue against a crucial role of c-kit in thyroid carcinoma cell proliferation. Further molecular targets of imatinib mesylate have to be analyzed to estimate a potential benefit of this drug for patients with dedifferentiated thyroid carcinoma.

Left ventricular volumes and mass in marathon runners and their association with cardiovascular risk factors

BACKGROUND

To assess left ventricular volumes and mass by cardiac magnetic resonance imaging in relation to conventional cardiovascular risk factors and coronary atherosclerotic plaque burden in master marathon runners aged > or =50 years.

METHODS

Cardiac MRI was performed in 105 clinically healthy male marathon runners (mean age 57.3 +/- 5.7 years, range 50-71 years) on a 1.5 T MR system (Avanto, Siemens, Germany). Cine steady state free precession images in standard long and short axes views were acquired to assess left ventricular volumes and mass. Cardiovascular risk factors (blood pressure, HDL/LDL cholesterol, smoking, body mass index) were assessed and coronary artery calcification (CAC) was quantified by electron beam computed tomography.

RESULTS

Left ventricular muscle mass (mean LVMM = 140 +/- 27 g; 73 +/- 13 g/m(2)) increased with increasing left ventricular end-diastolic volume (mean LVEDV = 137 +/- 32 ml; 72 +/- 15 ml/m(2)) (r = 0.41, P < 0.0001) and with systolic (r = 0.33, P = 0.005) and diastolic (r = 0.28, P = 0.005) blood pressures. Left ventricular EDV increased up to the age of 55 years, but decreased thereafter. Runners with LVMM > or =150 g had significantly higher CAC scores than runners with LVMM <150 g (median CAC score 110 vs. 25, P = 0.04).

CONCLUSIONS

Increases in LVMM and LVEDV may not only represent a response to exercise but are dependent on age and blood pressure, also. In addition, a left ventricular hypertrophy without an increase in volume may be an indicator for early subclinical cardiac alterations in response to risk factor exposure.

Retinol-binding protein 4 levels are elevated in polycystic ovary syndrome women with obesity and impaired glucose metabolism

OBJECTIVE

Insulin resistance and obesity are common features of the polycystic ovary syndrome (PCOS). Retinol-binding protein 4 (RBP4), a new fat-derived adipokine, has been described to be elevated in obesity and type 2 diabetes. The aim of the present study was to investigate whether serum RBP4 levels are correlated with metabolic parameters, indices of insulin resistance, and endocrine variables in German PCOS women.

DESIGN

We assessed the correlation between metabolic and endocrine parameters with RBP4 levels in 200 PCOS patients and 64 healthy controls.

METHODS

Serum RBP4 was measured by enzyme-linked immunosorbent assay (Immundiagnostik AG, Bensheim, Germany). In addition, anthropometric variables, clinical signs of hyperandrogenism, and body fat were evaluated, and a glucose tolerance test was performed to assess parameters of insulin resistance and glucose metabolism.

RESULTS

Taking the entire PCOS cohort, RBP4 levels were positively correlated with body mass index (BMI), body fat, waist circumference, fasting glucose, and area under the curve for glucose (all P<0.05), but not with indices of insulin resistance. On the other hand, PCOS women with impaired glucose metabolism had higher RBP4 levels than PCOS women with normal glucose metabolism (median 30.6, range 23.3-73.9 versus median 26.3, range 6.4-61.4, P<0.05). Furthermore, no differences were found in RBP4 levels between lean PCOS women and BMI-matched healthy controls.

CONCLUSION

In German PCOS women, serum RBP4 levels are associated with obesity and parameters of glucose metabolism but not with PCOS per se.