The IL-6-neutralizing sIL-6R-sgp130 buffer system is disturbed in patients with type 2 diabetes

Serum levels of interleukin-6 (IL-6) are increased in patients with type 2 diabetes (T2D). IL-6 exerts its pleiotropic effects via the IL-6 α-receptor (IL-6R), which exists in membrane-bound and soluble (sIL-6R) forms and activates cells via the β-receptor glycoprotein 130 (gp130). The nonsynonymous single-nucleotide polymorphism (SNP) rs2228145 (Asp358Ala) within the IL6R locus is associated with T2D. The aim of this study was to determine whether sIL-6R in combination with soluble gp130 (sgp130) is able to form an IL-6-neutralizing buffer in healthy subjects and whether this is disturbed in T2D. We found that sIL-6R-sgp130 indeed forms an IL-6-neutralizing buffer in the serum of healthy humans, whose capacity is controlled by the SNP of the IL-6R. Circulating sIL-6R-sgp130 levels were lower in T2D subjects (P < 0.001), whereas IL-6 was high and inversely correlated with sIL-6R (r = -0.57, P < 0.001), indicating a severe disturbance of the buffer. This phenomenon is also observed in sex- and age-matched patients with both T2D and atherosclerosis but not in patients with atherosclerosis alone. In conclusion, sIL-6R and sgp130 serum levels were significantly lower in T2D patients compared with healthy subjects or atherosclerosis patients, although IL-6 levels were high. These data suggest that disturbance of the protective buffer may be closely associated with T2D pathophysiology.

Assessment of endocrine disorders of the hypothalamicpituitary axis by nuclear medicine techniques

The following article reviews nuclear medicine techniques which can be used for assessment of endocrine disorders of the hypothalamic-pituitary axis. For planar and SPECT imaging somatostatin-receptor- and dopamine- D2-receptor-scintigraphy are the most widely distributed techniques. These nuclear medicine techniques may be indicated in selected cases to answer differential diagnostic problems. They can be helpful to search for presence and localization of receptor positive tissue. Furthermore they can detect metastasis in the rare cases of a pituitary carcinoma. Scintigraphy with Gallium-67 is suitable for further diagnostic evaluation in suspected hypophysitis. Other SPECT radiopharmaca do not have relevant clinical significance. F-18-FDG as PET radiopharmacon is not ideal because obvious pituitary adenomas could not be visualized. Other PET radiopharmaca including C-11-methionine, C-11-tyrosine, F-18-fluoroethylspiperone, C-11-methylspiperone, and C-11-raclopride are available in specialized centers only. Overall indications for nuclear medicine in studies for the assessment of endocrine disorders of the hypothalamic-pituitary-axis are rare. Original studies often report only about a small number of patients. According to the authors’ opinion the relevance of nuclear medicine in studies of clinically important endocrinologic fields, e. g. localization of small ACTH-producing pituitary adenomas, tumor localization in ectopic ACTH syndrome, localization of recurrent pituitary tissue, assessment of small incidentalomas, can not be definitely given yet.

Lipid Lowering Therapy and Stabilization of Atherosclerotic Plaques

Lipid-lowering therapy leads to a great reduction of cardiovascular complications, but has almost no effect on the degree of stenosis of coronary arteries. These and other studies have lead to a new paradigm of coronary artery disease, i. e. clinical prognosis is not only determined by the extent of a single stenosis, but mainly by the number and structure of atherosclerotic plaques. Rupture of an instable or vulnerable plaque, characterized by a large lipid-rich central core, inflammatory cells, and a thin fibrous cap, causes sudden thrombus formation and thereby acute coronary syndromes. There is accumulating evidence that cholesterol lowering can result in plaque stabilization and improvement of endothelial dysfunction.

[Incidental finding: elevated TSH level]

The use of thyroid-stimulating hormone (TSH) testing in routine laboratory screening and testing of TSH before administration of contrast medium, resulted in an increased number of incidentally detected elevated TSH levels. In the case of slightly increased values in asymptomatic patients, repeated measurement of TSH is recommended for confirmation. Confirmed elevated TSH levels should lead to additional measurements of the peripheral thyroid hormones, determination of thyroid autoantibodies and performance of thyroid gland ultrasound examination. The most common reasons for acquired subclinical and overt hypothyroidism are autoimmune diseases of the thyroid gland and in many cases substitution therapy with levothyroxine is then necessary. In subclinical hypothyroidism it remains unclear at which TSH levels the initiation of substitution therapy makes sense. In the case of simultaneously elevated peripheral thyroid hormones rare diseases, such as secondary hyperthyroidism and thyroid hormone resistance should be considered.

IL-6 blockade by monoclonal antibodies inhibits apolipoprotein (a) expression and lipoprotein (a) synthesis in humans

Lipoprotein (a) [Lp(a)] is a highly atherogenic lipid particle. Although earlier reports suggested that Lp(a) levels are mostly determined by genetic factors, several recent studies have revealed that Lp(a) induction is also caused by chronic inflammation. Therefore, we aimed to examine whether cytokine blockade by monoclonal antibodies may inhibit Lp(a) metabolism. We found that interleukin 6 (IL-6) blockade by tocilizumab (TCZ) reduced Lp(a) while TNF-α-inhibition by adalimumab in humans had no effect. The specificity of IL-6 in regulating Lp(a) was further demonstrated by serological measurements of human subjects (n = 1,153) revealing that Lp(a) levels are increased in individuals with elevated serum IL-6. Transcriptomic analysis of human liver biopsies (n = 57) revealed typical IL-6 response genes being correlated with the LPA gene expression in vivo. On a molecular level, we found that TCZ inhibited IL-6-induced LPA mRNA and protein expression in human hepatocytes. Furthermore, examination of IL-6-responsive signal transducer and activator of transcription 3 binding sites within the LPA promoter by reporter gene assays, promoter deletion experiments, and electrophoretic mobility shift assay analysis showed that the Lp(a)-lowering effect of TCZ is specifically mediated via a responsive element at -46 to -40. Therefore, IL-6 blockade might be a potential therapeutic option to treat elevated Lp(a) serum concentrations in humans and might be a noninvasive alternative to lipid apheresis in the future.

Caloric restriction increases serum testosterone concentrations in obese male subjects by two distinct mechanisms

The concentration of serum testosterone is mainly regulated by the testicular function, which is under control of the central hypothalamic-pituitary-gonadal axis. A certain amount of testosterone is converted into β-estradiol by adipose tissue. Obesity in men is often associated with decreased androgen levels. The aim of the present study was to examine the effect of caloric restriction on serum testosterone levels in obese men. Dietary intervention study was performed with a very low calorie diet (800 kcal/d) for 12 weeks. Thirteen obese human male subjects (median body mass index: 42.7 kg/m2) were included. Body composition was assessed by impedance analysis. Insulin sensitivity was estimated by leptin-to-adiponectin ratio (LAR). Testosterone (T), β-estradiol, albumin, sex hormone-binding globulin (SHBG), LH, and FSH serum concentrations were measured by enzyme immunoassays. Statistical analysis was performed on baseline and values after 3 months. Caloric restriction significantly increased total testosterone (6.97 nmol/l to 13.21 nmol/l; p=0.001) and SHBG (22.11 nmol/l to 42.12 nmol/l; p=0.001) concentrations in serum. This is caused by a significant improvement of the testicular function (LH/T: 0.36-0.20; p=0.005) and a significant reduction of the T/β-estradiol conversion rate (73.59-104.29; p=0.003). There was a significant negative correlation of improvement of testicular function and LAR (rs=-0.683 (p=0.042)). In obese men caloric restriction significantly increases the serum testosterone concentration. This is achieved by 2 distinct mechanisms, that is, improvement of testicular function and reduced conversion of testosterone to β-estradiol by aromatase activity of the adipose tissue.

Effects of lipid-lowering drugs on high-density lipoprotein subclasses in healthy men-a randomized trial

CONTEXT AND OBJECTIVE

Investigating the effects of lipid-lowering drugs on HDL subclasses has shown ambiguous results. This study assessed the effects of ezetimibe, simvastatin, and their combination on HDL subclass distribution.

DESIGN AND PARTICIPANTS

A single-center randomized parallel 3-group open-label study was performed in 72 healthy men free of cardiovascular disease with a baseline LDL-cholesterol of 111±30 mg/dl (2.9±0.8 mmol/l) and a baseline HDL-cholesterol of 64±15 mg/dl (1.7±0.4 mmol/l). They were treated with ezetimibe (10 mg/day, n = 24), simvastatin (40 mg/day, n = 24) or their combination (n = 24) for 14 days. Blood was drawn before and after the treatment period. HDL subclasses were determined using polyacrylamide gel-tube electrophoresis. Multivariate regression models were used to determine the influence of treatment and covariates on changes in HDL subclass composition.

RESULTS

Baseline HDL subclasses consisted of 33±10% large, 48±6% intermediate and 19±8% small HDL. After adjusting for baseline HDL subclass distribution, body mass index, LDL-C and the ratio triglycerides/HDL-C, there was a significant increase in large HDL by about 3.9 percentage points (P<0.05) and a decrease in intermediate HDL by about 3.5 percentage points (P<0.01) in both simvastatin-containing treatment arms in comparison to ezetimibe. The parameters obtained after additional adjustment for the decrease in LDL-C indicated that about one third to one half of these effects could be explained by the extent of LDL-C-lowering.

CONCLUSIONS

In healthy men, treatment with simvastatin leads to favorable effects on HDL subclass composition, which was not be observed with ezetimibe. Part of these differential effects may be due to the stronger LDL-C-lowering effects of simvastatin.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00317993.

Neuronal overexpression of insulin receptor substrate 2 leads to increased fat mass, insulin resistance, and glucose intolerance during aging

The insulin receptor substrates (IRS) are adapter proteins mediating insulin's and IGF1's intracellular effects. Recent data suggest that IRS2 in the central nervous system (CNS) is involved in regulating fuel metabolism as well as memory formation. The present study aims to specifically define the role of chronically increased IRS2-mediated signal transduction in the CNS. We generated transgenic mice overexpressing IRS2 specifically in neurons (nIRS2 (tg)) and analyzed these in respect to energy metabolism, learning, and memory. Western blot (WB) analysis of nIRS2 (tg) brain lysates revealed increased IRS2 downstream signaling. Histopathological investigation of nIRS2 (tg) mice proved unaltered brain development and structure. Interestingly, nIRS2 (tg) mice showed decreased voluntary locomotoric activity during dark phase accompanied with decreased energy expenditure (EE) leading to increased fat mass. Accordingly, nIRS2 (tg) mice develop insulin resistance and glucose intolerance during aging. Exploratory behavior, motor function as well as food and water intake were unchanged in nIRS2 (tg) mice. Surprisingly, increased IRS2-mediated signals did not change spatial working memory in the T-maze task. Since FoxO1 is a key mediator of IRS2-transmitted signals, we additionally generated mice expressing a dominant negative mutant of FoxO1 (FoxO1DN) specifically in neurons. This mutant mimics the effect of increased IRS2 signaling on FoxO-mediated transcription. Interestingly, the phenotype observed in nIRS2 (tg) mice was not present in FoxO1DN mice. Therefore, increased neuronal IRS2 signaling causes decreased locomotoric activity in the presence of unaltered exploratory behavior and motor coordination that might lead to increased fat mass, insulin resistance, and glucose intolerance during aging independent of FoxO1-mediated transcription.

Effects of lipid-lowering drugs on irisin in human subjects in vivo and in human skeletal muscle cells ex vivo

Context and Objective

The myokine irisin has been proposed to regulate energy homeostasis. Little is known about its association with metabolic parameters and especially with parameters influencing pathways of lipid metabolism. In the context of a clinical trial, an exploratory post hoc analysis has been performed in healthy subjects to determine whether simvastatin and/or ezetimibe influence serum irisin levels. The direct effects of simvastatin on irisin were also examined in primary human skeletal muscle cells (HSKMCs).

Design and Participants

A randomized, parallel 3-group study was performed in 72 men with mild hypercholesterolemia and without apparent cardiovascular disease. Each group of 24 subjects received a 14-day treatment with either simvastatin 40 mg, ezetimibe 10 mg, or their combination.

Results

Baseline irisin concentrations were not significantly correlated with age, BMI, estimated GFR, thyroid parameters, glucose, insulin, lipoproteins, non-cholesterol sterols, adipokines, inflammation markers and various molecular markers of cholesterol metabolism. Circulating irisin increased significantly in simvastatin-treated but not in ezetimibe-treated subjects. The changes were independent of changes in LDL-cholesterol and were not correlated with changes in creatine kinase levels. In HSKMCs, simvastatin significantly increased irisin secretion as well as mRNA expression of its parent peptide hormone FNDC5. Simvastatin significantly induced cellular reactive oxygen species levels along with expression of pro- and anti-oxidative genes such as Nox2, and MnSOD and catalase, respectively. Markers of cellular stress such as atrogin-1 mRNA and Bax protein expression were also induced by simvastatin. Decreased cell viability and increased irisin secretion by simvastatin was reversed by antioxidant mito-TEMPO, implying in part that irisin is secreted as a result of increased mitochondrial oxidative stress and subsequent myocyte damage.

Conclusions

Simvastatin increases irisin concentrations in vivo and in vitro. It remains to be determined whether this increase is a result of muscle damage or a protective mechanism against simvastatin-induced cellular stress.

Trial Registration

ClinicalTrials.gov NCT00317993 NCT00317993.

Insulin receptor signaling mediates APP processing and β-amyloid accumulation without altering survival in a transgenic mouse model of Alzheimer's disease

In brains from patients with Alzheimer's disease (AD), expression of insulin receptor (IR), insulin-like growth factor-1 receptor (IGF-1R), and insulin receptor substrate proteins is downregulated. A key step in the pathogenesis of AD is the accumulation of amyloid precursor protein (APP) cleavage products, β-amyloid (Aβ)(1-42) and Aβ(1-40). Recently, we and others have shown that central IGF-1 resistance reduces Aβ accumulation as well as Aβ toxicity and promotes survival. To define the role of IR in this context, we crossed neuron-specific IR knockout mice (nIR(-/-)) with Tg2576 mice, a well-established mouse model of an AD-like pathology. Here, we show that neuronal IR deficiency in Tg2576 (nIR(-/-)Tg2576) mice leads to markedly decreased Aβ burden but does not rescue premature mortality of Tg2576 mice. Analyzing APP C-terminal fragments (CTF) revealed decreased α-/β-CTFs in the brains of nIR(-/-)Tg2576 mice suggesting decreased APP processing. Cell based experiments showed that inhibition of the PI3-kinase pathway suppresses endosomal APP cleavage and decreases α- as well as β-secretase activity. Deletion of only one copy of the neuronal IGF-1R partially rescues the premature mortality of Tg2576 mice without altering total amyloid load. Analysis of Tg2576 mice expressing either a dominant negative or constitutively active form of forkhead box-O (FoxO)1 did not reveal any alteration of amyloid burden, APP processing and did not rescue premature mortality in these mice. Thus, our findings identified IR signaling as a potent regulator of Aβ accumulation in vivo. But exclusively decreased IGF-1R expression reduces AD-associated mortality independent of β-amyloid accumulation and FoxO1-mediated transcription.

Weight loss due to a very low calorie diet differentially affects insulin sensitivity and interleukin-6 serum levels in nondiabetic obese human subjects

Inflammatory mechanisms are involved in the pathogenesis of type 2 diabetes with interleukin (IL)-6 being particularly important. While long term exercise has been shown to be associated with reduction in IL-6 serum levels in several reports, the discussion on the effect of dietary intervention on IL-6 serum levels is controversial. In the present study, we aimed to investigate the effect of weight loss due to a very low calorie diet (VLCD) on insulin sensitivity and IL-6 serum levels in nondiabetic obese human individuals. 10 patients with obesity were examined during 12 weeks of a VLCD (800 kcal/d). Body composition was measured by impedance analysis. Blood samples were taken before, during, and after the dietary intervention. Leptin, adiponectin, and IL-6 serum levels were measured by ELISA. The body weight decreased significantly from 123.9±6.2-103.5±5.6 kg with a significant reduction in body fat content (43.2±2.3-36.1±3.1%). Leptin levels exhibited a significant decrease from 56.8±5.6-27.9±5.6 ng/ml while adiponectin levels increased significantly from 7.5±0.9-10.6±1.1 μg/ml. Thereby the leptin-to-adiponectin ratio, a novel marker for insulin sensitivity, significantly improved. Mean IL-6 serum concentrations were within the normal range (3.2±0.8 pg/ml) before the study and were not significantly altered by the nutritional therapy. Despite improvement of insulin sensitivity, IL-6 serum levels did not change throughout the study period, suggesting that in nondiabetic obese human subjects IL-6 might have only a minor role in the impairment of insulin sensitivity.

Pro-inflammatory wnt5a and anti-inflammatory sFRP5 are differentially regulated by nutritional factors in obese human subjects

BACKGROUND

Obesity is associated with macrophage infiltration of adipose tissue. These inflammatory cells affect adipocytes not only by classical cytokines but also by the secreted glycopeptide wnt5a. Healthy adipocytes are able to release the wnt5a inhibitor sFRP5. This protective effect, however, was found to be diminished in obesity. The aim of the present study was to examine (1) whether obese human subjects exhibit increased serum concentrations of wnt5a and (2) whether wnt5a and/or sFRP5 serum concentrations in obese subjects can be influenced by caloric restriction.

METHODOLOGY

23 obese human subjects (BMI 44.1 ± 1.1 kg/m(2)) and 12 age- and sex-matched lean controls (BMI 22.3 ± 0.4 kg/m(2)) were included in the study. Obese subjects were treated with a very low-calorie diet (approximately 800 kcal/d) for 12 weeks. Body composition was assessed by impedance analysis, insulin sensitivity was estimated by HOMA-IR and the leptin-to-adiponectin ratio and wnt5a and sFRP5 serum concentrations were measured by ELISA. sFRP5 expression in human adipose tissue biopsies was further determined on protein level by immunohistology.

PRINCIPAL FINDINGS

Pro-inflammatory wnt5a was not measurable in any serum sample of lean control subjects. In patients with obesity, however, wnt5a became significantly detectable consistent with low grade inflammation in such subjects. Caloric restriction resulted in a weight loss from 131.9 ± 4.0 to 112.3 ± 3.2 kg in the obese patients group. This was accompanied by a significant decrease of HOMA-IR and leptin-to-adiponectin ratio, indicating improved insulin sensitivity. Interestingly, these metabolic improvements were associated with a significant increase in serum concentrations of the anti-inflammatory factor and wnt5a-inhibitor sFRP5.

CONCLUSIONS/SIGNIFICANCE

Obesity is associated with elevated serum levels of pro-inflammatory wnt5a in humans. Furthermore, caloric restriction beneficially affects serum concentrations of anti-inflammatory sFRP5 in such subjects. These findings suggest a novel regulatory system in low grade inflammation in obesity, which can be influenced by nutritional therapy.

Neuron-specific deletion of a single copy of the insulin-like growth factor-1 receptor gene reduces fat accumulation during aging

Insulin, insulin-like growth factor-1 (IGF-1), and leptin signaling have been proposed to play an important role in regulating energy homeostasis. In order to specifically address the role of neuronal IGF-1 receptor (IGF-1R) signaling for energy expenditure and metabolism we used conditional mutagenesis. Deletion of one copy of the IGF-1R specifically in post-mitotic neurons (nIGF-1R(+/-) ) does not result in growth retardation or skeletal abnormalities. Interestingly, male nIGF-1R(+/-)  mice accumulate less fat mass during aging accompanied with decreased leptin levels compared to wild-type littermates. Furthermore, male nIGF-1R(+/-)  mice present with increased locomotor activity and energy expenditure. In contrast, female nIGF-1R(+/-)  mice remained nearly unaffected. Circadian pattern of locomotor activity and energy expenditure as well as food and water intake did not change. Consistent with increased locomotor activity, the respiratory quotient was shifted to increased fat oxidation in nIGF-1R(+/-)  mice. Surprisingly, serum IGF-1 and IGF-1 binding protein 3 (IGF-BP3) concentrations were decreased in nIGF-1R(+/-)  mice despite the presence of normal pituitaries suggesting a functional feedback mechanism via neuronal IGF-1Rs, which regulate serum IGF-1 levels. Thus, we show that neuron-specific IGF-1R deletion in male mice decreases body fat accumulation and increases energy expenditure during aging.

Central FoxO3a and FoxO6 expression is down-regulated in obesity induced diabetes but not in aging

BACKGROUND

Recent data suggest that insulin-like growth factor (IGF)-1 resistance in neurons prolongs longevity. In C. elegans this effect is mediated via DAF-16 the ortholog of the mammalian FoxO transcription factors. 3 different FoxO transcription factors (FoxOs) are expressed in rodent CNS: FoxO1, FoxO3a and FoxO6.

METHODS

To define whether the different FoxOs are region-, sex- and age-specifically expressed, we analyzed FoxO mRNA levels in different brain regions from 6, 16, 60 and 100 weeks old mice using realtime-PCR. In addition, we fed mice a high fat diet (HFD) to experimentally induce obesity and diabetes and analyzed FoxO mRNA in the different brain regions.

RESULTS

Interestingly, FoxO1 was predominantly expressed in the hippocampus whereas FoxO3a was quantitatively the most abundant FoxO in the neocortex. During aging, FoxO1 expression peaked in all brain regions at 16 weeks and FoxO6 showed its highest expression at 60 weeks in the parietal and occipital cortex. In 6 weeks old mice FoxO6 expression was higher in male compared to female mice in the hippocampus and all cortical regions. Surprisingly, in HFD animals FoxO3a was significantly less expressed in the cerebellum and all cortical regions compared to control animals. Even more dramatic, FoxO6 expression dropped about 80% in all brain regions in response to HFD.

CONCLUSION

Thus, FoxOs in the CNS showed a highly distinct expression, which in addition was age- and sex-dependent. In contrast to FoxO1, FoxO3a and FoxO6 were specifically diminished in the CNS of HFD animals possibly contributing to the reduced lifespan observed in these animals.

Lipid lowering in patients with chronic kidney disease: a SHARP turn in the wrong direction?

The question whether lipid-lowering treatment is associated with a decrease in cardiovascular morbidity and mortality in patients with chronic kidney disease has been disputed for a while, with recent trials in patients on haemodialysis failing to show benefit. Recently, the long-awaited results of the SHARP (Study of Heart And Renal Protection) trial were published. This randomized trial compared the effects of either simvastatin 20 mg plus ezetimibe 10 mg daily or placebo on the occurrence of a first major vascular event in 9720 patients with chronic kidney disease. There was a 17% relative risk reduction but no benefit on survival. We address our concerns regarding the conclusions drawn from this trial. The trial has a major design flaw by comparing the effects of two different lipid-lowering drugs with placebo. Although the SHARP trial showed that lipid lowering may be beneficial for patients with chronic kidney disease, the clinically as well as economically important question remains unanswered as to whether it was statin therapy and/or ezetimibe that mediated this effect. A great opportunity to investigate superiority, equipoise, or potential inferiority of ezetimibe compared to statins was missed.

Association between the interleukin-6 promoter polymorphism -174G/C and serum lipoprotein(a) concentrations in humans

BACKGROUND

Lipoprotein(a) [Lp(a)] is an independent risk factor for cardiovascular disease. The interleukin-6 (IL-6) receptor antagonist tocilizumab has been shown to lower serum Lp(a) concentrations. We investigated whether the IL-6 single nucleotide polymorphism -174G/C is associated with baseline serum Lp(a) concentrations.

METHODOLOGY/PRINCIPAL FINDINGS

We divided 2321 subjects from the Lipid Analytic Cologne (LIANCO) cohort into 2 groups, the ones with substantially elevated Lp(a), defined as concentrations ≥60 mg/dl (n = 510), and the ones with Lp(a) <60 mg/dl (n = 1811). The association with the genotypes GG (33.7%), GC (50.75%) and CC (15.55%) was investigated. The GC and the CC genotype were associated with a significantly increased odds ratio of having substantially elevated Lp(a) concentrations (OR = 1.3, 95% CI 1.04 to 1.63, P = 0.02 and OR = 1.44, 95% CI 1.06 to 1.93, P = 0.018). These associations remained significant after adjusting for age, sex, smoking behavior, body mass index, serum lipoproteins, hypertension and diabetes. Of these covariates, only LDL cholesterol was significantly and independently associated with elevated Lp(a) concentrations.

CONCLUSIONS/SIGNIFICANCE

The IL-6 single nucleotide polymorphism -174G/C is associated with increased odds of having elevated Lp(a). Whether this association plays a role in the Lp(a)-lowering effects of IL-6 receptor antagonists remains to be established.

Disease management programs in type 2 diabetes: quality of care

OBJECTIVES

To determine whether disease management programs (DMPs) for type 2 diabetes mellitus (T2DM) can improve some processes of care and intermediate outcomes.

STUDY DESIGN

Two cross-sectional registries of patients with T2DM were used for data extraction before (previous cohort) and after (recent cohort) introduction of DMPs in Germany (N = 78,110).

METHODS

In the recent cohort, 15,293 patients were treated within the DMPs and 9791 were not. Processes of care, medications, and intermediate outcomes (achievement of treatment targets for low-density lipoprotein [LDL] cholesterol, blood pressure, and glycosylated hemoglobin [A1C]) were analyzed using multi- variable, multilevel logistic regression, adjusting for patient case-mix and physician-level clustering to derive odds ratios and 95% confidence intervals (CIs).

RESULTS

Availability of structured diabetes education and of lipid, blood pressure, and A1C measurements increased over time. In DMP patients, availability was significantly higher for blood pressure and A1C but not for lipid measurements. Prescription of angiotensin-converting enzyme inhibitors, oral antidiabetic drugs, and insulin increased over time and was more common in DMP patients. Statin prescription increased over time but was not influenced by DMP status. Intermediate outcomes improved over time, but DMPs had no influence on intermediate outcomes except for reaching LDL cholesterol targets (odds ratio 1.12 [95% CI 1.06, 1.19] in favor of DMPs).

CONCLUSIONS

While there may be some unmeasured confounding, our data suggest that improvement in processes of care by DMPs, as implemented in Germany, only partially translates into improvement of intermediate outcomes.

Adipose tissue macrophages inhibit adipogenesis of mesenchymal precursor cells via wnt-5a in humans

In patients with obesity and type 2 diabetes, adipose tissue is infiltrated by macrophages known to alter adipogenesis of mesenchymal precursor cells via secretion of proinflammatory cytokines. Recently, it has been shown that under certain conditions, immune cells can also express wnt-5a, a factor known to inhibit adipogenesis in humans. Therefore, in this study we aimed to investigate whether macrophages affect adipogenesis of mesenchymal precursor cells via wnt-5a. Wnt-5a was found to be expressed in adipose tissue macrophages in obese and type 2 diabetic human subjects in vivo by immunohistochemistry of adipose tissue biopsies. Furthermore, wnt-5a was detectable in circulating CD14(+) blood monocytes of human subjects with obesity and type 2 diabetes on RNA level by real-time PCR. Besides expression analysis in vivo, we also performed functional studies to explore the role of wnt-5a in low-grade inflammation of adipose tissue. In a cell culture experiment, macrophage-conditioned differentiation medium inhibited adipogenesis of 3T3-L1 cells. This inhibitory effect was restored by adding neutralising anti-wnt-5a antibodies. In conclusion, our data indicate that macrophages alter adipogenesis of 3T3-L1 cells not only via classical proinflammatory cytokines, but also via wnt signalling molecules.

Effects of inhibition of interleukin-6 signalling on insulin sensitivity and lipoprotein (a) levels in human subjects with rheumatoid diseases

Background

Interleukin-6 (IL-6) is a pro-inflammatory cytokine that has been found to be increased in type 2 diabetic subjects. However, it still remains unclear if these elevated IL-6 levels are co-incidental or if this cytokine is causally related to the development of insulin resistance and type 2 diabetes in humans. Therefore, in the present study we examined insulin sensitivity, serum adipokine levels and lipid parameters in human subjects before and after treatment with the IL-6 receptor antibody Tocilizumab.

Methodology/Principal Findings

11 non-diabetic patients with rheumatoid disease were included in the study. HOMA-IR was calculated and serum levels for leptin, adiponectin, triglycerides, LDL-cholesterol, HDL-cholesterol and lipoprotein (a) (Lp (a)) were measured before as well as one and three months after Tocilizumab treatment. The HOMA index for insulin resistance decreased significantly. While leptin concentrations were not altered by inhibition of IL-6 signalling, adiponectin concentrations significantly increased. Thus the leptin to adiponectin ratio, a novel marker for insulin resistance, exhibited a significant decrease. Serum triglycerides, LDL-cholesterol and HDL-cholesterol tended to be increased whereas Lp (a) levels significantly decreased.

Conclusions/Significance

Inhibition of IL-6 signalling improves insulin sensitivity in humans with immunological disease suggesting that elevated IL-6 levels in type 2 diabetic subjects might be causally involved in the pathogenesis of insulin resistance. Furthermore, our data indicate that inhibition of IL-6 signalling decreases Lp (a) serum levels, which might reduce the cardiovascular risk of human subjects.

Comparative efficacy and safety of aliskiren and irbesartan in patients with hypertension and metabolic syndrome

Metabolic syndrome, a cluster of risk factors that increase the risk of cardiovascular morbidity and mortality, is common in patients with hypertension. Chronic renin-angiotensin-aldosterone system (RAAS) activation, shown by elevated plasma renin activity (PRA), is implicated in many of the features of metabolic syndrome. The direct renin inhibitor aliskiren may be of benefit in this patient group as aliskiren targets the RAAS at the rate-limiting step. In this double-blind study, 141 patients with hypertension (mean baseline BP 155/93 mm Hg) and metabolic syndrome (modified National Cholesterol Education Program ATP III criteria) were randomized to aliskiren 300 mg or irbesartan 300 mg once daily. Patients treated with aliskiren 300 mg had their mean sitting blood pressure (BP) lowered by 13.8/7.1 mm Hg after 12 weeks, significantly greater (P≤0.001) than the 5.8/2.8 mm Hg reduction observed in patients treated with irbesartan 300 mg. A significantly greater proportion of patients treated with aliskiren achieved BP control to <135/85 mm Hg (29.2 vs 16.7% with irbesartan; P=0.019). Aliskiren treatment led to a 60% decrease in PRA from baseline, whereas irbesartan increased PRA by 99% (both P<0.001). Aliskiren and irbesartan had similar effects on glucose and lipid profiles and on a panel of biomarkers of inflammation and cardiovascular risk. Both aliskiren and irbesartan were well tolerated. Collectively, these results suggest that aliskiren 300 mg may offer treatment benefits compared with irbesartan 300 mg for BP reduction in patients with hypertension and metabolic syndrome.