The association between diabetes status, HbA1c, diabetes duration, microvascular disease, and bone quality of the distal radius and tibia as measured with high-resolution peripheral quantitative computed tomography-The Maastricht Study.

In this small cross-sectional study of predominantly well-treated participants with relatively short-term type 2 diabetes duration, HbA1c > 7% (53 mmol/mol) was associated with lower cortical density and thickness and higher cortical porosity at the distal radius, lower trabecular thickness at the distal tibia, and higher trabecular number at both sites. INTRODUCTION: To examine the association between diabetes status and volumetric bone mineral density (vBMD), bone microarchitecture and strength of the distal radius and tibia as assessed with HR-pQCT. Additionally-in participants with type 2 diabetes (T2DM), to examine the association between HbA1c, diabetes duration, and microvascular disease (MVD) and bone parameters. METHODS: Cross-sectional data from 410 (radius) and 198 (tibia) participants of The Maastricht Study (mean age 58 year, 51% female). Diabetes status (normal glucose metabolism, prediabetes, or T2DM) was based on an oral glucose tolerance test and medication history. RESULTS: After full adjustment, prediabetes and T2DM were not associated with vBMD, bone microarchitecture, and strength of the radius and tibia, except for lower trabecular number (Tb.N) of the tibia (- 4%) in prediabetes and smaller cross-sectional area of the tibia (- 7%) in T2DM. In T2DM, HbA1c > 7% was associated with lower cortical vBMD (- 5%), cortical thickness (- 16%), higher cortical porosity (+ 20%) and Tb.N (+ 9%) of the radius, and higher Tb.N (+ 9%) and lower trabecular thickness (- 13%) of the tibia. Diabetes duration > 5 years was associated with higher Tb.N (+ 6%) of the radius. The presence of MVD was not associated with any bone parameters. CONCLUSIONS: In this study with predominantly well-treated T2DM participants with relatively short-term diabetes duration, inadequate blood glucose control was negatively associated with cortical bone measures of the radius. In contrast, trabecular number was increased at both sites. Studies of larger sample size are warranted for more detailed investigations of bone density and bone quality in patients with T2DM.

The association between glucose metabolism status, diabetes severity and a history of fractures and recent falls in participants of 50 years and older-the Maastricht Study.

In this cohort of relatively young and well-treated participants with type 2 diabetes, we found no association between diabetes status and a history of previous fractures and recent falls. Furthermore, no association between diabetes severity and previous fractures or recent falls was found. INTRODUCTION: In this study, we examined the association between glucose metabolism status and historical fractures or recent falls and the effect of diabetes severity (glucose control, insulin use, and diabetes duration) on falls and fractures in the participants with type 2 diabetes. METHODS: Cross-sectional data from 2005 participants of the Maastricht Study. Falls in the past 6 months and fractures ≥age 50 were assessed by questionnaire. Glucose metabolism status (normal glucose metabolism, impaired glucose metabolism, or type 2 diabetes) was based on the oral glucose tolerance test and medication use. RESULTS: In the completely adjusted model, the odds for a fall were not significantly higher in those with impaired glucose metabolism status (OR (95%CI) 1.28 (0.93-1.77)) or with type 2 diabetes (OR (95%CI) 1.21 (0.80-1.81)) compared with the group with normal glucose metabolism. Within the group with type 2 diabetes, there were no significant differences with regard to reported falls between participants with HbA1c >7 % (53 mmol/mol) versus HbA1c ≤7 % (OR (95%CI) 1.05 (0.58-1.90)), insulin users versus non-insulin users (OR (95%CI) 1.51 (0.79-2.89)), and with a diabetes duration >5 versus ≤5 years (OR (95%CI) 0.52 (0.46-1.47)). Similarly, neither glucose metabolism status nor diabetes severity was associated with prior fractures. CONCLUSIONS: Glucose metabolism status was not significantly associated with previous fractures and recent falls. In addition, in this cohort of relatively young and well-treated participants with type 2 diabetes, diabetes severity was not associated with previous fractures and recent falls.

Lower verbal intelligence is associated with diabetic complications and slower walking speed in people with Type 2 diabetes: the Maastricht Study.

AIMS: To determine the association of verbal intelligence, a core constituent of health literacy, with diabetic complications and walking speed in people with Type 2 diabetes. METHODS: This study was performed in 228 people with Type 2 diabetes participating in the Maastricht Study, a population-based cohort study. We examined the cross-sectional associations of score on the vocabulary test of the Groningen Intelligence Test with: 1) determinants of diabetic complications (HbA1c , blood pressure and lipid level); 2) diabetic complications: chronic kidney disease, neuropathic pain, self-reported history of cardiovascular disease and carotid intima-media thickness; and 3) walking speed. Analyses were performed using linear regression and adjusted in separate models for potential confounders and mediators. Significant age- and sex-adjusted associations were additionally adjusted for educational level in a separate model. RESULTS: After full adjustment, lower verbal intelligence was associated with the presence of neuropathic pain [odds ratio (OR) 1.18, 95% CI 1.02;1.36], cardiovascular disease (OR 1.14, 95% CI 1.01;1.30), and slower walking speed (regression coefficient -0.011 m/s, 95% CI -0.021; -0.002 m/s). These associations were largely explained by education. Verbal intelligence was not associated with blood pressure, glycaemic control, lipid control, chronic kidney disease or carotid intima-media thickness. CONCLUSIONS: Lower verbal intelligence was associated with the presence of some diabetic complications and with a slower walking speed, a measure of physical functioning. Educational level largely explained these associations. This implies that clinicians should be aware of the educational level of people with diabetes and should provide information at a level of complexity tailored to the patient.

Comparison of fatty acid proportions in serum cholesteryl esters among people with different glucose tolerance status: the CoDAM study.

BACKGROUND AND AIM: Altered fatty acid patterns in blood may be associated with insulin resistance and related disorders. We investigated whether serum proportions of cholesteryl fatty acids and desaturase activity are associated with glucose tolerance status and insulin resistance. METHODS AND RESULTS: Data were obtained from a cross-sectional study among 471 Dutch participants aged ≥40 years. Individual fatty acids in serum cholesteryl esters were determined and endogenous conversions by desaturases were estimated from product-to-precursor ratios. Proportions of fatty acids were compared among participants with normal glucose tolerance, impaired glucose metabolism and newly diagnosed type 2 diabetes. Partial Spearman correlation coefficients between fatty acids and homeostasis model assessment-insulin resistance (HOMA-IR) were calculated. Adjustments were made for lifestyle and nutritional factors. The proportions of total saturated, mono-unsaturated, trans- and poly-unsaturated fatty acids did not differ significantly between groups, but several individual fatty acids did; the proportions of C18:0 and C20:3n6 were higher, whereas those of C18:1n7 and C20:4n6 were lower in participants with type 2 diabetes compared with those with normal glucose tolerance. Activity of Δ5-desaturase, that is, ratio of C20:4n6 to C20:3n6, was lower (p < 0.01) in participants with type 2 diabetes (7.4) than with normal glucose tolerance (8.4). HOMA-IR was correlated positively with Δ9-desaturase activity (r = 0.11, p < 0.01) and inversely with Δ5-desaturase activity (r = -0.21, p < 0.01). CONCLUSION: The observed lower Δ5-desaturase activity in participants with type 2 diabetes and its inverse association with HOMA-IR suggest that changes in fatty-acid metabolism may play a role in the aetiology of type 2 diabetes.

Preadipocytes of type 2 diabetes subjects display an intrinsic gene expression profile of decreased differentiation capacity.

OBJECTIVE: Insulin resistance and type 2 diabetes mellitus (T2DM) are associated with increased adipocyte size, altered secretory pattern and decreased differentiation of preadipocytes. In this study, we identified the underlying molecular processes in preadipocytes of T2DM patients, a characteristic for the development of T2DM. DESIGN AND PARTICIPANTS: Preadipocyte cell cultures were prepared from subcutaneous fat biopsies of seven T2DM patients (age 53 ± 12 years; body mass index (BMI) 34 ± 5 kg m(-2)) and nine control subjects (age 51 ± 12 years; BMI 30 ± 3 kg m(-2)). Microarray analysis was used to identify altered processes between the T2DM and control preadipocytes. RESULTS: Gene expression profiling showed changed expression of transcription regulators involved in adipogenesis and in extracellular matrix remodeling, actin cytoskeleton and integrin signaling genes, which indicated decreased capacity to differentiate. Additionally, genes involved in insulin signaling and lipid metabolism were downregulated, and inflammation/apoptosis was upregulated in T2DM preadipocytes. CONCLUSION: Decreased expression of genes involved in differentiation can provide a molecular basis for the reduced adipogenesis of preadipocytes of T2DM subjects, leading to reduced formation of adipocytes in subcutaneous fat depots, and ultimately leading to ectopic fat storage.

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

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

Wnt5b stimulates adipogenesis by activating PPARgamma, and inhibiting the beta-catenin dependent Wnt signaling pathway together with Wnt5a.

Correct Wnt signaling is required for adipogenesis and alterations occur in Type 2 diabetes mellitus (T2DM). Gene expression studies showed that beta-catenin independent Wnt5b was down-regulated in T2DM preadipocytes, while its paralog Wnt5a was unchanged. Our study aimed at defining the expression profile and function of Wnt5a and Wnt5b during adipogenesis by determining their effect on aP2 and PPARgamma expression and assessing the level of beta-catenin translocation in mouse 3T3-L1 preadipocytes. Additionally, we explored the effect on adipogenic capacity by Wnt5b overexpression in combination with stimulation of the beta-catenin dependent or beta-catenin independent Wnt signaling. Expression of Wnt5b was, like Wnt5a, down-regulated upon induction of differentiation and both inhibit beta-catenin dependent Wnt signaling at the initiation of adipogenesis. Wnt5b additionally appears to be a potent enhancer of adipogenic capacity by stimulation of PPARgamma and aP2. Down-regulation of Wnt5b could therefore contribute to decreased adipogenesis observed in T2DM diabetic subjects.

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

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

Paraoxonase 1 phenotype distribution and activity differs in subjects with newly diagnosed Type 2 diabetes (the CODAM Study).

AIMS: Paraoxonase 1 (PON1) is an antioxidant high-density lipoprotein-bound enzyme, which was recently found to be expressed in the islets of Langerhans. A substitution (Q/R) at position 192 results in enzymes with different activity. Oxidation has been implicated in the onset of diabetes, and it can be hypothesized that PON1 may have a protective effect on diabetes. Our aim was to compare PON1 activities and PON1 Q/R phenotypes in subjects with different degrees of glucose intolerance. METHODS: We examined 566 members of the Cohort study of Diabetes and Atherosclerosis Maastricht (CoDAM), including subjects with normal glucose tolerance (NGT, n = 298), impaired glucose regulation (IGR, n = 128), newly diagnosed Type 2 diabetes (nDM, n = 78) and treated, that is to say known, Type 2 diabetes (kDM, n = 64). PON1 activity was measured in serum using paraoxon and diazoxon as substrates. The PON1 phenotype was determined using two-dimensional enzyme analysis. RESULTS: The RR-phenotype was significantly more frequent in nDM compared with NGT subjects (14.1 vs. 6.0%, P = 0.05). Adjusted for the PON1 phenotype, subjects with nDM had significant lower PON1 activity towards paraoxon and diazoxon than subjects with NGT. Adjusted odds ratios comparing the RR-variant with the QQ-variant were 2.17 [95% confidence interval (CI): 0.90-5.24] for impaired glucose tolerance, 2.84 (95% CI: 1.03-7.83) for nDM, 2.13 (95% CI; 0.61-7.42) for kDM and 2.65 (95% CI: 1.10-6.40) for total diabetes mellitus. CONCLUSIONS: An aberrant PON1 phenotype distribution and PON1 activity were observed in early diabetes. In addition, the higher state of oxidative stress may affect the future development of complications.

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

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

The association between insulin use and volumetric bone mineral density, bone micro-architecture and bone strength of the distal radius in patients with type 2 diabetes - The Maastricht study.

Type 2 diabetes mellitus (T2DM) has been associated with an increased risk of fractures, despite normal to increased bone mineral density (BMD). Insulin use is one of the factors linked to this increased fracture risk. However, direct negative effects of insulin on bone quality are not expected since insulin is thought to be anabolic to bone. In this cross-sectional study the association between insulin use and volumetric BMD (vBMD), bone micro-architecture and bone strength of the distal radius, as measured with HR-pQCT, was examined. Data from 50 participants with T2DM of The Maastricht Study (mean age 62±7.5years, 44% women) was used. Participants were classified as insulin user (n=13) or non-insulin user (n=37) based on prescription data. Linear regression analysis was used to estimate the association between current insulin use and HR-pQCT derived parameters. After adjustment for age, sex, body mass index, glycated hemoglobin A1c and T2DM duration, insulin use was associated with lower total vBMD (standardized beta (ß):-0.56 (95% CI:-0.89 to -0.24)), trabecular vBMD (ß:-0.58 (95% CI:-0.87 to -0.30)), trabecular thickness (ß:-0.55 (95% CI:-0.87 to -0.23)), cortical thickness (ß:-0.41 (95% CI:-0.74 to -0.08)), log cortical pore volume (ß:-0.43 (95% CI:-0.73 to -0.13)), bone stiffness (ß:-0.39 (95% CI:-0.62 to -0.17)) and failure load (ß:-0.39 (95% CI:-0.60 to -0.17)) when compared to the non-insulin users. Insulin use was not associated with cortical vBMD, trabecular number, trabecular separation, cortical porosity and cortical pore diameter. This study indicates that insulin use is negatively associated with bone density, bone micro-architectural and bone strength parameters. These findings may partly explain the previously observed increased fracture risk in insulin users, although there may be residual confounding by other factors related to disease severity in insulin users.

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

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

Associations of advanced glycation end-products with cognitive functions in individuals with and without type 2 diabetes: the maastricht study.

CONTEXT: Advanced glycation end-products (AGEs) are thought to be involved in the pathogenesis of Alzheimer's disease. AGEs are products resulting from nonenzymatic chemical reactions between reduced sugars and proteins, which accumulate during natural aging, and their accumulation is accelerated in hyperglycemic conditions such as type 2 diabetes mellitus. OBJECTIVE: The objective of the study was to examine associations between AGEs and cognitive functions. DESIGN, SETTING, AND PARTICIPANTS: This study was performed as part of the Maastricht Study, a population-based cohort study in which, by design, 215 participants (28.1%) had type 2 diabetes mellitus. MAIN OUTCOME MEASURES: We examined associations of skin autofluorescence (SAF) (n = 764), an overall estimate of skin AGEs, and specific plasma protein-bound AGEs (n = 781) with performance on tests for global cognitive functioning, information processing speed, verbal memory (immediate and delayed word recall), and response inhibition. RESULTS: After adjustment for demographics, diabetes, smoking, alcohol, waist circumference, total cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, and lipid-lowering medication use, higher SAF was significantly associated with worse delayed word recall (regression coefficient, b = -0.44; P = .04), and response inhibition (b = 0.03; P = .04). After further adjustment for systolic blood pressure, cardiovascular disease, estimated glomerular filtration rate, and depression, associations were attenuated (delayed word recall, b = -0.38, P = .07; response inhibition, b = 0.02, P = .07). Higher pentosidine levels were associated with worse global cognitive functioning (b = -0.61; P = .04) after full adjustment, but other plasma AGEs were not. Associations did not differ between individuals with and without diabetes. CONCLUSION: We found inverse associations of SAF (a noninvasive marker for tissue AGEs) with cognitive performance, which were attenuated after adjustment for vascular risk factors and depression.

Soluble receptors for tumor necrosis factor-alpha (TNF-R p55 and TNF-R p75) in familial combined hyperlipidemia.

We investigated the potential role of the 75 kD receptor for tumor necrosis factor-alpha (TNF-alpha) (TNFRSF1B, located on chromosome 1 band p36.2) as a modifier gene in familial combined hyperlipidemia (FCH), based on previous linkage and association data. Age-corrected values for the soluble (s) extracellular domain of TNF-R p75 were lower in 156 well-characterized hyperlipidemic (HL) FCH relatives than in 168 normolipidemic (NL) relatives (P<0.01). Plasma concentrations of the soluble domain of the 55 kD receptor (sTNF-R p55, the other TNF-alpha receptor) did not differ between HL and NL relatives. In conditional logistic regression analysis, plasma sTNF-R p75 concentration was the only non-lipid variable that contributed significantly to prediction of affected FCH status (regression coefficient=-0.413, P=0.01). The present findings have potentially important diagnostic and therapeutic implications in FCH.

Disrupted co-ordination of Pax-8 and thyroid transcription factor-1 gene expression in a dedifferentiated rat thyroid tumour cell line derived from FRTL-5.

The mutant rat thyroid cell line FRTL-5/TA, isolated from a non-functional tumour which originated spontaneously from wild-type FRTL-5 cells, shows autonomous TSH-independent growth and loss of the thyroid-specific phenotype, lacking thyroid-specific expression of thyroglobulin (Tg) and thyroid peroxidase (TPO) genes. To investigate the role of the transcription factors Pax-8 and thyroid transcription factor-1 (TTF-1) in rat thyroid tumorigenesis, RNA expression of these two thyroid-specific nuclear factors was measured in FRTL-5/TA tumour cells and compared with the expression in wild-type FRTL-5 cells. TTF-1 gene expression was similar to that in wild-type FRTL-5, and showed a similar down-regulation after stimulation with TSH. The finding suggested normal TTF-1 mRNA and protein expression in both cell lines. By contrast, Pax-8 mRNA transcript signal was markedly reduced in FRTL-5/TA cells, reaching levels as low as 8% of the normal, basal level in FRTL-5 cells. These data indicated that the loss of thyroid-specific expression of Tg and TPO genes in FRTL-5/TA cells was not related to changes in TTF-1 gene expression but rather to reduced Pax-8 gene expression. It was concluded that a disruption of the co-ordinated expression of TTF-1 and Pax-8 is implicated in the loss of thyroid phenotype of FRTL-5/TA cells in terms of reduced Tg and TPO expression.

Oestrogen receptor independent expression of progestin receptors in human meningioma--a review.

Human meningiomas are rich in progestin receptors (PR), which are expressed in this tissue in an oestrogen independent fashion. In the search for an explanation of this observation, the existence of a protein in human meningioma cytosol which is capable of binding to a synthetic oestrogen responsive element (ERE) has been demonstrated. Using reverse transcriptase, PCR mRNA encoding for the wild-type oestrogen receptor (ER) was found. In addition, several splice variants of ER mRNA have been identified in human meningioma tissue, including variants lacking exons 4, 5 and 7. We found the ER delta 4 protein to have no transcriptional activity and the ER delta 7 protein reportedly is dominant negative. These mutants therefore probably are not responsible for the autonomous PR synthesis in human meningioma. The ER delta 5 protein, by contrast, has been reported to have oestrogen independent transcriptional activity and it is tempting to speculate that this protein is similar or identical to the ERE binding protein we have found in human meningioma. The role of wild type ER mRNA is presently unclear. Activation of other signal transduction pathways in meningioma does not lead to an increased PR concentration. The promoter area of the meningioma PR gene should be investigated for the possible sensitivity to other transcription factors.

Dantrolene sodium diminishes exercise-induced muscle damage in the rat.

We tested the hypothesis that calcium from the sarcoplasmic reticulum contributes to exercise-induced muscle damage. Dantrolene sodium (Dantrium) is a muscle relaxant that affects the flux of calcium over the sarcoplasmic membrane. Rats were treated with dantrolene sodium for a week before a 2 h run on a treadmill. We measured the total creatine kinase activity and isoenzyme composition in plasma before and after exercise. We also prepared muscle sections to correlate the biochemical data with morphological evidence of muscle damage. The treated rats showed a marked decrease (34%) in exercise-induced enzyme efflux, caused by a decrease in the muscle specific isoenzyme: instead of a 13-fold increase found in control rats we observed only a 6.5-fold increase in treated animals. The latter showed significantly less muscle damage 48 h later. It is concluded that dantrolene sodium protects the muscle against exercise-induced damage. The possible mechanism of this protection, and its applications in neuromuscular disease are discussed.

Progesterone receptor synthesis in human meningiomas: relation to the estrogen-induced proteins pS2 and cathepsin-D and influence of epidermal growth factor, Forskolin and phorbol ester in vitro.

Autonomous expression of progesterone receptors (PR) in human meningiomas is well established. To evaluate whether, similar to progesterone receptors, other estrogen-inducible proteins are also autonomously expressed in meningiomas, concentrations of pS2 and cathepsin-D (Cath-D) were measured in 52 meningiomas. No pS2 protein was detectable in 52/52 tested meningiomas. The Cath-D protein was measurable in all 52 meningiomas, but the mean concentration of Cath-D in meningioma cytosols was 2.4-fold lower than that of a group of 54 breast tumors (p < 0.001). These results indicate that autonomous expression is a PR-related rather than an estrogen receptor-related phenomenon and, consequently, that estradiol is probably not responsible for PR synthesis in human meningiomas. To evaluate the role of other, non-estradiol-dependent signalling pathways in PR synthesis, the effects of EGF, Forskolin and phorbol ester on PR synthesis were tested in vitro. No PR was detectable after the addition of EGF to six different primary cultures. Forskolin and TPA addition caused a morphological change in meningioma cells, but did not induce PR or pS2 synthesis in two different primary meningioma cultures. We conclude that PR synthesis in human meningiomas cannot be triggered by switching on the signalling pathways activated by these growth factors.

BclI glucocorticoid receptor polymorphism is associated with greater body fatness: the Hoorn and CODAM studies.

CONTEXT: The BclI polymorphism in the glucocorticoid receptor (GR) gene is associated with enhanced glucocorticoid (GC) sensitivity. OBJECTIVE: Our objective was to investigate the association of the BclI polymorphism with body fatness and insulin resistance. DESIGN AND SETTING: We conducted an observational cohort study, combining data from 2 cohort studies enriched with individuals with impaired glucose metabolism and/or diabetes mellitus type 2 (DM2). PATIENTS AND METHODS: We examined 1228 participants (mean age 64.7 years, 45% women) from the Cohort Study on Diabetes and Atherosclerosis Maastricht (CODAM, n = 543) and the Hoorn Study (n = 685). Body mass index (BMI), waist and hip circumferences, and waist-to-hip ratio (WHR) were obtained; insulin resistance was estimated using the homeostasis model assessment for insulin resistance (HOMA2-IR). RESULTS: We identified 519 noncarriers (CC), 540 heterozygous (CG) carriers, and 169 homozygous (GG) carriers of the G-allele of the BclI polymorphism. Homozygous carriers had a higher BMI (28.9 vs 27.9 kg/m(2)) and waist (99.6 vs 97.2 cm) and hip (105.5 vs 103.2 cm) circumference compared with noncarriers, also after adjustment for age, sex, cohort, glucose tolerance, and lifestyle risk factors: ß = 0.94 kg/m(2) (95% confidence interval, 0.24-1.63), ß = 2.84 cm (0.95;4.73) and ß = 2.38 cm (0.88-3.87), respectively. Similar results were obtained when comparing homozygous carriers with heterozygous carriers: ß = 1.03 kg/m(2) (0.34-1.72), ß = 2.20 cm (0.31-4.08) and ß = 1.99 cm (0.51-3.48), respectively. There were no differences in WHR. Ln-HOMA2-IR was higher in GG carriers compared with CG carriers; 0.29 vs 0.17 [ß = 0.09 (0.01-0.17)], but this effect was attenuated after adjustment for BMI [ß = 0.04 (-0.04 to 0.11)]. CONCLUSION: Homozygous carriers of the BclI polymorphism of the GR gene have significantly greater total body fatness, contributing to higher HOMA2-IR, compared with heterozygous carriers and noncarriers.

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

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