The influence of improved glycaemic control with insulin and sulphonylureas on acute phase and endothelial markers in Type II diabetic subjects

Review: Endothelial dysfunction in type 2 diabetes

Dysfunction of the endothelial cell monolayer leads to increased vascular tone and permeability and a prothrombotic environment. Type 2 diabetes is a state of insulin resistance, hyperglycaemia and dyslipidaemia characterised by high cardiovascular risk and accelerated atherosclerosis. Many mechanisms by which hyperglycaemia can result in endothelial dysfunction have now been identified. However, the presence of endothelial dysfunction in normoglycaemic first-degree relatives and insulin resistant subjects is less well understood and less readily explained by `confounding' variables. We suggest that insulin's effects on glucose transport in classical target tissues and nitric oxide production in the endothelium are fundamentally linked at a molecular level. It is expected that greater understanding of these underlying mechanisms will lead to novel approaches to prevention of cardiovascular disease in both diabetic and non-diabetic subjects.

Effects of bromocriptine mesylate on homocysteine and high-sensitivity C-reactive protein levels in patients with type-2 diabetes mellitus

Introduction: Quick release bromocriptine (BROM-QR), currently approved for glycemic control, reduces the risk of cardiovascular events in adults with type-2 diabetes mellitus (T2DM). This study evaluates the effect of BROM-QR on homocysteine (HOMC) and high sensitive C-reactive protein (hs-CRP), the biochemical markers of coronary atherosclerosis/inflammation, in patients with uncontrolled T2DM.

Methods: In this non-randomized, before-and-after clinical trial, patients with uncontrolled T2DM on stable doses of two oral hypoglycemic agents received BROM-QR for 6 months. The change in serum concentrations of HOMC was the primary endpoint. Anthropometric measurements such as body mass index (BMI) and waist circumference were measured at the baseline and at the completion of treatment along with fasting plasma glucose (FPG), HbA1c, total cholesterol, triglyceride, creatinine and hs-CRP. Multivariate regression analysis was performed to identify factors associated with changes in the levels of HOMC.

Results: In 64 patients (46 completed 6 months of treatment), age was 55±7 years and the duration of T2DM was 8.0 ± 4.4 years. On enrollment, mean HbA1c, FPG, hs-CRP and HOMC levels were 9.0± 1.3 percent, 184 ± 42 mg/dL, 3.8± 3.4 mg/dl and 10.8 ± 6.2 micromole/L; respectively. Mean decrease of 0.7 ± 1.1 percent for HbA1c (P = 0.001) and 22 ± 44 mg/dL for FPG was observed (P = 0.002). HOMC levels decreased to 8.5 ± 5.2 micromole/L (P = 0.011) while hs-CRP levels remained unchanged at 3.7 ± 2.9 mg/dL (P = 0.835).

Conclusion: While HOMC and HbA1c levels decreased significantly after 6 months of treatment with BROM-QR in patients with T2DM, serum levels of hs-CRP, total cholesterol and triglyceride did not significantly change.

Therapeutic angiogenesis improves fibrinolytic imbalance in patients with critical limb ischemia

The mechanisms of fibrinolysis have been suggested to be linked to the pathogenesis of peripheral artery disease. The impact of therapeutic angiogenesis on the parameters of fibrinolysis was studied in critical limb ischemia (CLI). CLI patients (N = 29) and blood donors as controls (N = 29) were enrolled. Bone marrow (600 ± 50 ml) was centrifuged (3200g, 20 min, 22°C), bone marrow-derived mononuclear cells (100-120 ml) were separated by Optipress I and implanted into the ischemic limb using intramuscular injections. ELISA was employed for the assessment of plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) levels. Patients were followed-up prior to the procedure and after 1, 3 and 6 months. All stage-IV patients (N = 22) had ischemic lesions. The lesions resolved in 10 patients. Five patients underwent major amputation; they all were stage-IV. Ischemic lesions persisted in seven patients beyond 6 months. The t-PA levels were higher in patients compared with the healthy controls both at baseline (P < 0.01) and after 6 months (P < 0.05). No significant changes were observed in the t-PA levels during the follow-up. PAI-1 was higher in patients than in the healthy individuals at baseline (P < 0.001) and at month 1 (P < 0.05). However, no difference in PAI-1 levels between the patients and the healthy individuals was found after 3 and 6 months. The PAI-1 levels were significantly downregulated during the follow-up compared with the baseline (P < 0.0001). Therapeutic angiogenesis for the CLI downregulates PAI-1 levels, thus having a systemic effect on fibrinolysis.

Partial hepatic resistance to IL-6-induced inflammation develops in type 2 diabetic mice, while the anti-inflammatory effect of AMPK is maintained

Interleukin-6 (IL-6) induces hepatic inflammation and insulin resistance, and therapeutic strategies to counteract the IL-6 action in liver are of high interest. In this study, we demonstrate that acute treatment with AMP-activated protein kinase (AMPK) agonists AICAR and metformin efficiently repressed IL-6-induced hepatic proinflammatory gene expression and activation of STAT3 in a mouse model of diet-induced type 2 diabetes, bringing it back to basal nonstimulated level. Surprisingly, the inflammatory response in liver induced by IL-6 administration in vivo was markedly blunted in the mice fed a high-fat diet, compared to lean chow-fed controls, while this difference was not replicated in vitro in primary hepatocytes derived from these two groups of mice. In summary, our work reveals that partial hepatic IL-6 resistance develops in the mouse model of type 2 diabetes, while the anti-inflammatory action of AMPK is maintained. Systemic factors, rather than differences in intracellular IL-6 receptor signaling, are likely mediating the relative impairment in IL-6 effect.

The inflammatory status score including IL-6, TNF-α, osteopontin, fractalkine, MCP-1 and adiponectin underlies whole-body insulin resistance and hyperglycemia in type 2 diabetes mellitus

A state of subclinical systemic inflammation is characteristically present in obesity/insulin resistance and type 2 diabetes mellitus (T2DM). The aim of the study was to develop an integrated measure of the circulating cytokines involved in the subclinical systemic inflammation and evaluate its relation with whole-body insulin sensitivity and glucose metabolism in T2DM. T2DM patients (n = 17, M/F 13/4, age = 55.0 ± 1.7 years, BMI = 33.5 ± 1.5 kg/m(2), HbA(1c) = 7.7 ± 0.3%) and normal glucose-tolerant (NGT) subjects (n = 15, M/F 7/8, age = 49.1 ± 2.5 years, BMI = 31.8 ± 1.2 kg/m(2), HbA(1c) = 5.6 ± 0.1%) were studied in a cross-sectional design. Whole-body insulin sensitivity was quantified by the euglycemic clamp. Beta-cell function [disposition index (DI)] was calculated using insulin and glucose values derived from an oral glucose tolerance test and the euglycemic clamp. Body fat mass was evaluated by dual-energy X-ray absorptiometry. Plasma cytokine [TNF-α, IL-6, MCP-1, osteopontin, fractalkine and adiponectin] values were divided into quintiles. A score ranging from 0 (lowest quintile) to 4 (highest quintile) was assigned. The inflammatory score (IS) was the sum of each cytokine score from which adiponectin score was subtracted in each study subject. Inflammatory cytokine levels were all higher in T2DM. IS was higher in T2DM as compared to NGT (10.0 ± 1.1 vs. 4.8 ± 0.8; p < 0.001). IS positively correlated with fasting plasma glucose (r = 0.638, p < 0.001), 1-h plasma glucose (r = 0.483, p = 0.005), 2-h plasma glucose (r = 0.611, p < 0.001) and HbA1c (r = 0.469, p = 0.007). IS was inversely correlated with insulin sensitivity (r = -0.478, p = 0.006) and DI (r = -0.523, p = 0.002). IS did not correlate with BMI and body fat mass. IS was an independent predictor of fasting plasma glucose and had a high sensibility and sensitivity to predict insulin resistance (M/I < 4). A state of subclinical inflammation defined and quantifiable by inflammatory score including TNF-α, IL-6, MCP-1, osteopontin, fractalkine and adiponectin is associated with both hyperglycemia and whole-body insulin resistance in T2DM.

Association of TNF-α with insulin resistance in type 2 diabetes mellitus

Background & objectives:

TNF-α is an adipocytokine that has been implicated in the development of insulin resistance. Dysregulation of TNF-α production has been implicated in a variety of human diseases including type 2 diabetes mellitus. We aimed to find out the association of TNF-α levels with insulin resistance, body mass index and waist hip ratio; and to elicit its role with respect to duration of the disease, if any.

Methods:

50 type-2 diabetic patients attending Narayana Medical Hospital, Nellore, were studied. Body mass index and Waist hip ratio were calculated. Homeostasis model assessment method was used to calculate insulin resistance (HOMA IR) and per cent β cell function (HOMA B). Insulin was estimated by chemiluminescence method and TNF-α by ELISA method. The subjects were arbitrarily categorized into three groups based on duration of diabetes. Group 1 included subjects with diabetes of less than 5 yr duration, group 2 included diabetics of 6-10 yr duration and group 3 greater than 10 yr duration.

Results:

Our study revealed a significant correlation between TNF-α levels and BMI (P=0.006), the correlation being stronger in males when compared to females. A significant correlation was found between per cent β cell function and TNF-α (P=0.008). TNF-α correlated significantly with HOMA IR, HOMA B and insulin, in group 2 diabetes.

Interpretation & conclusions:

Our results suggest the possible role of TNF-α in the pathogenesis of type-2 diabetes mellitus and the importance of reducing obesity to prevent elevated levels of the cytokine and related complications.

Comparative Effects of Glibenclamide and Metformin on C-Reactive Protein and Oxidant/Antioxidant Status in Patients with Type II Diabetes Mellitus

OBJECTIVES

This study aimed to compare the effects of metformin and glibenclamide on high sensitivity serum C-reactive protein (hs-CRP) and oxidative stress, represented by serum malondialdehyde (MDA) and total antioxidant status (TAS) in newly-diagnosed patients with Type 2 diabetes mellitus (DM) at baseline and after 2 months of therapy in comparison to controls.

METHODS

The subjects, recruited from Al-Wafaa Centre for Diabetes Management and Research, Iraq, November 2009 to January 2011, were 103 newly-diagnosed Type 2 DM patients; 53 were prescribed metformin and 50 glibenclamide. The control group was 40 apparently healthy volunteers. Blood samples were taken from all subjects after overnight fasting. Sera were separated and assays of hs-CRP, MDA and TAS were done. After 2 months monotherapy, the blood samples and assays were repeated.

RESULTS

There were significant differences between patients prescribed metformin and glibenclamide and the controls with regard to serum hs-CRP, MDA and TAS. There was a significant reduction in the serum MDA and a significant raise in the serum TAS levels, with no significant effects on serum hs-CRP levels after metformin therapy, but no significant effects on these parameters after glibenclamide therapy. The percentage of variation in these parameters after both drugs, showed a significant raise in serum TAS levels with the metformin therapy with no significant effects in serum MDA and hs-CRP.

CONCLUSION

Metformin positively affected the oxidant/antioxidant balance in newly-diagnosed Type 2 DM patients with no significant effects on acute phase reaction protein. Glibenclamide had no significant effects on oxidant/antioxidant balance and acute phase reaction protein.

The association between C-reactive protein levels and insulin therapy in obese vs nonobese veterans with type 2 diabetes mellitus

The authors studied the association between insulin use and C-reactive protein (CRP) levels in obese (body mass index > or = 30 kg/m(2)) and nonobese (body mass index <30 kg/m(2)) patients with type 2 diabetes at the Providence Veterans Affairs Medical Center. There were 64 nonobese participants (insulin use and average daily dose, 23.4% and 7.0+/-18.2 units at baseline and 27.1% and 9.3+/-21.0 units at follow-up, respectively) and 106 obese participants (insulin use and daily dose, 39.6% and 28.2+/-47.3 units at baseline and 43.0% and 28.7+/-47.7 units at follow-up, respectively). Both use and daily dose of insulin were modeled with CRP levels of participants upon discharge from an intensive cardiac risk management clinic and at a 1-year follow-up visit using a linear mixed effects model for repeated measures. There was a significant direct association between log CRP and both insulin use and daily dose for nonobese participants (beta=0.3, P=.03 and beta=0.01, P=.02, respectively) but not for obese participants (P=.8 and P=.5, respectively). Due to the association between insulin therapy and CRP in nonobese patients, these results may aid clinicians in deciding on the initiation of insulin therapy for nonobese diabetic patients when noninsulin alternatives are available.

The fixed combination of pioglitazone and metformin improves biomarkers of platelet function and chronic inflammation in type 2 diabetes patients: results from the PIOfix study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is characterized by a proinflammatory and procoagulant condition. This study investigates the impact of a pioglitazone plus metformin therapy on biomarkers of inflammation and platelet activation in comparison to a treatment with glimepiride plus metformin.

METHODS

The study was designed as a multicenter, randomized, double-blinded two-arm trial. Patients with T2DM and dyslipidemia under metformin monotherapy with hemoglobin A1c value between 6.5% and 9.0% were eligible for trial participation. Blood was drawn at baseline and after 24 weeks of treatment from patients of five centers. Markers of inflammation and thrombocyte function (soluble CD40 ligand, thromboxane, vWillebrand factor, adhesion molecules, clotting reaction) were evaluated subsequently in a central laboratory.

RESULTS

A total of 46 patients were included in the final analyses. Mean (± standard deviation) age was 58.5 ± 9.0 years (13 women, 33 men; disease duration 6.3 ± 5.0 years; body mass index 32.0 ± 4.8 kg/m(2)). A total of 25 patients were treated with pioglitazone plus metformin, and 21 patients were in the glimepiride arm. There was a significant decline of E-selectin (-3.7 ± 4.8 ng/ml, p < .001 versus baseline), vWillebrand factor (-19.5 ± 32.0%, p < .05), and high-sensitivity C-reactive protein concentrations (-1.08 ± 0.91 mg/liter, p < .05) in the metformin + pioglitazone arm only (metformin + glimepiride, -0.5 ± 3.4 ng/ml, +1.4 ± 33.2%, + 0.08 ± 0.72 mg/liter, respectively, all not significant). Also, all other surrogate markers for platelet function and inflammation showed slight improvements in the metformin + pioglitazone arm but not in the metformin + glimepiride arm.

CONCLUSIONS

The fixed metformin + pioglitazone combination treatment showed an overall improvement of laboratory surrogate markers, indicating improvement of platelet function and of chronic systemic inflammation, which was not seen with metformin + glimepiride.

Clinical significance of high-sensitivity C-reactive protein in cardiovascular disease

Large-scale prospective cohort studies consistently demonstrate a strong, independent relationship between high-sensitivity (hs) C-reactive protein (CRP) and incident cardiovascular events, with a magnitude of effect similar to, or larger than, that of blood pressure and lipid levels. As a biomarker of inflammation, hsCRP levels also predict incident Type 2 diabetes and modify the risk associated with the metabolic syndrome. Recent work further demonstrates that the addition of hsCRP to information provided by traditional risk factors improves risk classification, particularly for individuals otherwise considered to be at intermediate risk. Although there remains no direct evidence that lowering hsCRP lowers vascular risk, optimal clinical outcomes have been observed in statin trials among patients who not only reduced low-density lipoprotein cholesterol below 1.8 mmol/l (70 mg/dl), but who also reduced hsCRP below 2 mg/l. In addition to statins, CRP levels are lowered by diet, exercise and smoking cessation, all of which are known to lower vascular event rates. Whether or not CRP represents a causal agent in atherosclerosis is controversial and an area in need of further research. However, this controversy does not diminish the clinical utility of hsCRP as a biomarker of risk that, if appropriately used in clinical practice, can substantially improve clinical care.

High-sensitivity C-reactive protein predicts cardiovascular risk in diabetic and nondiabetic patients: effects of insulin-sensitizing treatment with pioglitazone

Systemic inflammatory activity has turned out to play a key pathogenic role in vascular atherosclerosis, insulin resistance, and type 2 diabetes mellitus. Inflammatory biomarkers may therefore be a valuable tool for risk evaluation. Among them, the best evidence to date supports the use of high-sensitivity C-reactive protein (hs-CRP) to monitor insulin resistance and cardiovascular risk in diabetic and nondiabetic individuals. Data suggest that hs-CRP may also participate directly in the process of atherogenesis. A growing number of clinical trials tested the hypothesis that antidiabetic drugs specifically targeting insulin resistance could benefit individuals by reducing inflammation, atherogenesis, and thus cardiovascular risk. One such class are the thiazolidinediones (pioglitazone and rosiglitazone). These agents act as selective ligands of the nuclear transcription factor peroxisome proliferator-activated receptor-gamma (PPARgamma). This article reviewed published data on hs-CRP changes with the thiazolidinedione agent pioglitazone. Here we found pronounced insulin-sensitizing and anti-inflammatory properties in different clinical settings, including diabetic and nondiabetic individuals. Coadministration of pioglitazone to antilipidemic statin therapy resulted in additional effects on low-grade inflammation, and hs-CRP reduction has been demonstrated to occur independently of glucose lowering. The anti-inflammatory effect appeared to be a rapid physiologic reaction on PPARgamma activation and could be observed within a short-term interval after starting pioglitazone therapy. In summary, clinical study results underline the benefit of an early insulin resistance treatment to oppose systemic vascular inflammation and cardiometabolic syndrome in patients with elevated levels of high-sensitivity C-reactive protein.

Independent anti-inflammatory effect of insulin in newly diagnosed type 2 diabetes

BACKGROUND

Although insulin has been reported to have an anti-inflammatory effect, whether this effect is independent of its property to reduce blood glucose with insulin treatment in type 2 diabetes has not been investigated in detail. The purpose of this study was to evaluate the independent anti-inflammatory effect of insulin in patients with newly diagnosed type 2 diabetes.

RESEARCH DESIGN AND METHODS

An 8-week, randomized, parallel-group study that enrolled 90 patients with newly diagnosed type 2 diabetes, who were randomly assigned to receive either insulin or metformin, was carried out. The doses of insulin and metformin were titrated according to fasting plasma glucose (FPG) and postprandial plasma glucose (PPG) during the 4 weeks; the target of FPG was 126 mg/dL and that of PPG was 160 mg/dL. The blood glucose levels were kept stabilized till the end of the study. The serum concentrations of high-sensitive C-reactive protein (hsCRP) and interleukin (IL)-6 were measured before starting the study and 4 and 8 weeks after initiation of insulin or metformin therapy.

RESULTS

After 4 weeks of dose titration, the levels of FPG were reduced in the two groups compared to baseline (p < 0.001), but there was no significant difference between the two groups (p > 0.05). During the next 4 weeks' treatment, the levels of FPG were stable, but the serum concentration of hsCRP and IL-6 was markedly reduced in the insulin-treated group compared with that in the metformin-treated group (p < 0.001).

CONCLUSIONS

Our data suggest that insulin has an anti-inflammatory effect that is independent of the reduction it causes in blood glucose.

Effect of early insulin therapy on nuclear factor kappaB and cytokine gene expressions in the liver and skeletal muscle of high-fat diet, streptozotocin-treated diabetic rats

To clarify the effect of early insulin therapy on nuclear factor kappaB (NFkappaB) pathway and inflammatory cytokine responses in the liver and skeletal muscle in type 2 diabetes. High-fat diet and low dose streptozotocin (STZ) induced diabetic rats were given NPH insulin or gliclazide for 3 weeks initiated at the 3rd day after STZ injection as early treatment and NPH for 3 weeks at 1 month as late treatment. Intraperitoneal glucose tolerance test (IPGTT) was performed at 3rd day after the end of treatment. Early interventions caused a decrease in glucose-insulin index in IPGTT, promoted glucose transporter 4 (Glut4) gene and protein expressions in muscle and reduced phosphoenolpyruvate carboxykinase (PEPCK) protein levels in the liver. There was an increase in inhibitor kappaB (IkappaBalpha) protein and a decrease in NFkappaB p65 DNA binding activity. A decreased level in mRNAs encoding tumor necrosis factor (TNF)alpha in the liver and muscle and interleukin (IL)-1beta in the liver were observed. Our results suggested that early insulin treatment inhibits NFkappaB activity and inflammatory cytokine responses in the liver and skeletal muscle that were involved in the amelioration of insulin resistance in type 2 diabetic rats.

Hepatic dysfunction and insulin insensitivity in type 2 diabetes mellitus: a critical target for insulin-sensitizing agents

The liver plays an essential role in maintaining glucose homeostasis, which includes insulin-mediated processes such as hepatic glucose output (HGO) and uptake, as well as in clearance of insulin itself. In type 2 diabetes, the onset of hyperglycaemia [itself a potent inhibitor of hepatic glucose output (HGO)], alongside hyperinsulinaemia, indicates the presence of hepatic insulin insensitivity. Increased HGO is central to the onset of hyperglycaemia and highlights the need to target hepatic insulin insensitivity as a central component of glucose-lowering therapy. The mechanisms underlying the development of hepatic insulin insensitivity are not well understood, but may be influenced by factors such as fatty acid oversupply and altered adipocytokine release from dysfunctional adipose tissue and increased liver fat content. Furthermore, although the impact of insulin insensitivity as a marker of cardiovascular disease is well known, the specific role of hepatic insulin insensitivity is less clear. The pharmacological tools available to improve insulin sensitivity include the biguanides (metformin) and thiazolidinediones (rosiglitazone and pioglitazone). Data from a number of sources indicate that thiazolidinediones, in particular, can improve multiple aspects of hepatic dysfunction, including reducing HGO, insulin insensitivity and liver fat content, as well as improving other markers of liver function and the levels of mediators with potential involvement in hepatic function, including fatty acids and adipocytokines. The current review addresses this topic from the perspective of the role of the liver in maintaining glucose homeostasis, its key involvement in the pathogenesis of type 2 diabetes and the tools currently available to reduce hepatic insulin insensitivity.

The markers of inflammation and endothelial dysfunction in correlation with glycated haemoglobin are present in type 2 diabetes mellitus patients but not in their relatives

The aim of this study is to test several biomarkers of inflammation, of endothelial dysfunction, glycated haemoglobin, and their reflection in arterial dilatation, in patients with type 2 diabetes mellitus and in their relatives, in order to demonstrate if relatives present markers as a form of precocious indicators of diabetes mellitus. Individuals between 30 and 55 years of age and without clinical arterial disease were divided in three groups: type 2 diabetes mellitus patients without complications (12 men and 18 women); first degree relatives of type 2 diabetes mellitus (14 men and 20 women); and control individuals (9 men and 16 women). Body composition was measured with a bioelectrical impedance analyzer and endothelial function with an eco-Doppler device. We determined glucose, insulin, C-peptide, glycated haemoglobin, fibrinogen, E-selectin, P-selectin, soluble intercellular cell adhesion molecule-1 (ICAM-1), soluble vascular cell adhesion molecule-1 (VCAM-1), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), C-reactive protein (CRP) in plasma. We also studied endothelium independent dilatation and endothelium dependent dilatation.

THE RESULTS

ICAM-1 and VCAM-1 were significantly higher in the diabetic group (237.5+/-43.4 and 692.5+/-168.6 ng/l) than in controls (197.4+/-51.2 and 573.5+/-121.1 ng/l, p=0.011 and 0.013, respectively), but were not higher in the family group (224.5+/-45.2 and 599.8+/-150.4 ng/l). CRP was higher in the diabetic group (3.35+/-3.27 mg/l) than in the other groups (1.28+/-1.29 and 1.61+/-1.54 mg/l, p=0.002) and correlated with glycated haemoglobin. The non-endothelium mediated dilatation was lesser in the diabetic group than in the family group (17.3+/-6.1 vs. 24+/-8, p=0.029) and controls. In conclusion patients with uncomplicated type 2 diabetes, but not their relatives, have biochemical markers of sub-clinical inflammation in relationship with glycated haemoglobin and dysfunction of the endothelial cells markers. In these patients endothelium independent dilatation is more affected than endothelium dependent dilatation.

Effects of antidiabetic and antihyperlipidemic agents on C-reactive protein

Type 2 diabetes mellitus (DM) increases the risk of cardiovascular disease, a major cause of morbidity and mortality. Central to type 2 DM is insulin resistance, a proinflammatory, hypercoagulable state that predisposes patients to develop cardiovascular disease and that is associated with risk factors for atherosclerosis including dyslipidemia, hypertension, inflammation, and altered hemostasis. Atherosclerosis is recognized as a chronic inflammatory disease of the arteries. C-reactive protein (CRP) is an acute-phase response protein that is considered both a marker of inflammation and a predictor of cardiovascular events including myocardial infarction, stroke, peripheral arterial disease, and sudden cardiac death. Evidence indicates that CRP has a direct proatherogenic effect through up-regulation of angiotensin II type 1 receptors and through the stimulation of other proinflammatory factors. Patients with type 2 DM tend to have higher CRP concentrations than do those without it, suggesting an increased role of inflammation in the accelerated atherosclerosis seen in these patients. Reducing CRP concentrations through lifestyle changes or pharmacotherapeutics could have clinical benefit; long-term studies are needed to determine whether reductions in CRP concentrations translate into improved cardiovascular outcomes. Because glucose and lipid levels as well as CRP concentrations are often elevated in patients with type 2 DM, an agent that positively affects multiple cardiovascular risk factors would be most beneficial. This article reviews available data on antidiabetic and antihyperlipidemic agents that reduce CRP concentrations in addition to their primary effect of lowering glucose or lipid levels.

Effect of rosiglitazone on factors related to endothelial dysfunction in patients with type 2 diabetes mellitus

The effect of the insulin sensitizer rosiglitazone (RSG) on biological markers of endothelial dysfunction in subjects with type 2 diabetes mellitus (T2DM) was investigated in a 12-week, multi-center, randomized, double-blind study. One hundred and thirty-six subjects aged 40-70 years, with FPG > or = 7.0 and < or = 15.0 mmol/l, previously treated with a single oral anti-diabetic agent or diet/exercise, were randomized to RSG 8 mg/day (n=65) or placebo (PBO, n=71). Results revealed that RSG significantly reduced soluble (s)E-selectin by -10.9% (P=0.004) compared with PBO, but did not significantly alter soluble vascular cell adhesion molecule-1 (+0.6%, P=NS). Compared with PBO, RSG also significantly reduced plasminogen activator inhibitor-1 (-36.9%, P<0.001), tissue plasminogen activator antigen (-22.7%, P<0.001), FPG (-2.8 mmol/l, P<0.001), fasting fructosamine (-42.0 mg/dl, P<0.001). Post-prandial AUC(0-4h) for free fatty acids (FFAs) reduced by -6.5 mg/dl*h from baseline (P=0.03), a change that positively and significantly correlated with changes in sE-selectin (r=0.22, P=0.05). The incidence of adverse events was similar in the two groups (RSG: 35.4%; PBO: 40.8%); the majority mild or moderate. These data support the hypothesis that, in patients with T2DM, rosiglitazone has beneficial effects on biological markers of endothelial dysfunction. Improvements in insulin sensitivity and decreases in FFAs may play a role in these effects.

Interrelationships between inflammation, C-reactive protein, and insulin resistance

The recognition that inflammation plays a fundamental role in atherothrombosis has led to the measurement of circulating inflammatory biomarkers such as high-sensitivity C-reactive protein (hs-CRP) as a means of improving cardiovascular disease detection and prevention. Clinically, levels of hs-CRP >3 mg/L indicate elevated risk for myocardial infarction and stroke, even among apparently healthy individuals with low-to-normal lipid levels. Emerging laboratory and epidemiologic data now link inflammation and hs-CRP to insulin resistance in that hs-CRP levels have been associated with impaired insulin sensitivity and the development of dysglycemic conditions, including the cardiometabolic syndrome and incident type 2 diabetes. hs-CRP has also been associated with each of the individual components of the cardiometabolic syndrome. Furthermore, in large prospective studies, hs-CRP adds prognostic information about cardiovascular risk beyond that provided by the cardiometabolic syndrome. These findings have led to discussion about the addition of hs-CRP measurement to the current definition of the cardiometabolic syndrome to improve detection of risk for both diabetes and cardiovascular events in patients. Multiple clinical studies are now underway that are evaluating whether agents traditionally used to improve glycemic control may also significantly reduce hs-CRP.

Pioglitazone has anti-inflammatory effects in patients with Type 2 diabetes

BACKGROUND

Type 2 diabetes is characterized by increased acute phase serum proteins. They are also risk factors for cardiovascular disease. We wanted to study how improvement of glycemic control with pioglitazone or glibenclamide affects their serum concentrations.

MATERIALS AND METHODS

A total of 59 patients with Type 2 diabetes (age 57.3+/-1.2 yr, glycosylated hemoglobin (HbA1c) 8.3+/-0.7%, body mass index (BMI) 31.4+/-0.8 kg/m2) participated in the study. They were previously treated either with diet alone or in combination with one oral antihyperglycemic medicine. After a 1-week lead-in period on diet only, the patients were randomized to pioglitazone or glibenclamide. Blood samples for alpha-1-acid glycoprotein (A1GP), Creactive protein (CR P) and serum amyloid A (SAA) were taken before the treatments and during the therapy after 20 and 52 weeks.

RESULTS

Baseline A1GP correlated with CR P (r=0.70, p<0.001) and fasting glucose (r=0.32, p<0.02). Baseline CR P correlated with HbA1c (r=0.26, p<0.05) and insulin (r=0.37, p<0.01). The anti-hyperglycemic effect was comparable with HbA1c levels decreasing both in the pioglitazone (from 8.18+/-0.09% to 7.63+/-0.17%, p<0.01) and glibenclamide (from 8.35+/-0.12% to 7.77+/-0.16%, p<0.01) groups. Pioglitazone treatment was associated with a reduction in A1GP at 20 weeks (p<0.001) and at 52 weeks (p<0.05) as compared to baseline. The significance remained also after comparison to glibenclamide therapy (p<0.001 and p<0.05, 20 and 52 weeks respectively). CR P was also more reduced in the pioglitazone group at 20 weeks of treatment (p<0.05).

CONCLUSIONS

Inflammatory factors and markers of hyperglycemia are associated in patients with Type 2 diabetes. Pioglitazone treatment results in reduced A1GP concentration suggesting an anti-inflammatory effect.

Sulfatide increases adiponectin and decreases TNF-alpha, IL-6, and IL-8 in human adipose tissue in vitro

Type 2 diabetes is associated with decreased levels of the glycosphingolipid sulfatide, as well as a state of low-grade inflammation. Sulfatide is reported to have anti-inflammatory properties in other cell-types. In the present study, the effects of sulfatide on adipokine (adiponectin, TNF-alpha, IL-6, and IL-8) production in human adipose tissue (AT) was investigated in vitro. Isolated human adipocytes and AT cultures were incubated with sulfatide isolated from pig brain [sulfatide containing a variety of fatty acids or isoforms of sulfatide with defined, saturated fatty acids with 16 (C16:0) or 24 (C24:0) carbon atoms]. Adiponectin production was increased 50-80%, by all sulfatide preparations. Only the C16:0 isoform decreased TNF-alpha, IL-6, and IL-8 production 20-30%. The C16:0 sulfatide has been shown to activate potassium channels in beta-cells, and glibenclamide, an ATP-sensitive K+-(KATP) channel blocker, reversed the C16:0-induced decrement in stimulated TNF-alpha, IL-6, and IL-8 release in adipocytes. Glibenclamide on its own was without effect on the production of adiponectin, TNF-alpha, IL-6, and IL-8. In conclusion, this study shows that, sulfatide exerts anti-inflammatory effects in human adipocytes and AT in vitro. Accordingly, the reported low serum levels of sulfatide in patients with type 2 diabetes might be of importance in relation to the chronic low-grade inflammatory state found in this disease.

Cardiovascular disease prevention in patients with type 2 diabetes: The role of oral anti-diabetic agents

Multiple risk factor intervention is essential in order to prevent cardiovascular (CV) disease in patients with diabetes. Therefore, to reduce atherothrombotic events, an ideal oral anti-diabetic agent should be able to modulate most, and preferably all, cardiovascular risk factors associated with diabetes. Of the currently available agents, the insulin sensitisers (metformin, thiazolidinediones) seem to have most promise in cardiovascular protection. Metformin has a positive effect on several CV risk factors; outcome studies have shown that this agent reduces cardiac events in overweight subjects with diabetes. In a similar manner, thiazolidinediones (rosiglitazone, pioglitazone) have a wide spectrum of activity, favourably modulating most risk factors, with evidence to suggest a reduction in CV events with this class of drugs. Agents in the sulphonylurea group have beneficial, though inconsistent, effects on some risk factors but outcome studies have failed to show a cardioprotective role for these agents. New classes of drugs to manage type 2 diabetes are currently at various stages of development and their role in prevention of cardiovascular disease awaits evaluation. At present, first-line management of insulin-resistant type 2 diabetes should utilise metformin, with the addition of thiazolidinediones and sulphonylureas to achieve optimal glycaemic control.

Women with polycystic ovary syndrome are sensitive to the TNF-alpha-lowering effect of glucose-induced hyperinsulinaemia

BACKGROUND

Restoration of near-euglycaemia by intensive insulin therapy results in decreased serum levels of inflammatory mediators. The authors investigated whether the anti-inflammatory effect of insulin was independent of its glucose-lowering action and if this effect was intact in insulin-resistant women with the polycystic ovary syndrome (PCOS) characterized by low-grade chronic inflammation.

MATERIALS AND METHODS

Blood was drawn on the third and sixth days after progestin-induced withdrawal bleeding in 20 young non-diabetic women with PCOS and once between the third and sixth days of the menstrual cycle in 21 age-matched lean healthy control women during a 75-g oral glucose tolerance test (oGTT). Serum insulin, glucose and tumour necrosis factor alpha (TNF-alpha) concentrations were measured after 0, 30, 60, 90 and 120 min.

RESULTS

The increase in insulin and glucose concentrations during the oGTT was significantly more pronounced in patients with PCOS (one patient with impaired fasting glucose, one patient with impaired glucose tolerance, three patients with both) compared with healthy controls. The TNF-alpha serum concentrations decreased in patients with PCOS (mean of both days, P = 0.004). In patients and in controls, there was an inverse correlation between the serum concentrations of insulin and of TNF-alpha during oGTT (for patients, a mean of both days, P = 0.009; for controls, P = 0.047), but not between the serum concentrations of glucose and TNF-alpha.

CONCLUSIONS

The decrease in TNF-alpha concentrations during oGTT and the inverse correlation between endogenous hyperinsulinaemia and serum TNF-alpha concentrations suggested an anti-inflammatory effect of moderately-high insulin concentrations. This occurred despite the presence of moderate hyperglycaemia. These findings also demonstrated a preserved responsiveness of inflammatory mediators to insulin in PCOS.

Diabetes, hyperglycemia, and inflammation in older individuals: the health, aging and body composition study

OBJECTIVE

The objective of this study was to assess the association of inflammation with hyperglycemia (impaired fasting glucose [IFG]/impaired glucose tolerance [IGT]) and diabetes in older individuals.

RESEARCH DESIGN AND METHODS

Baseline data from the Health, Aging and Body Composition study included 3,075 well-functioning black and white participants, aged 70-79 years.

RESULTS

Of the participants, 24% had diabetes and 29% had IFG/IGT at baseline. C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) levels (P < 0.001) were significantly higher among diabetic participants and those with IFG/IGT. Odds of elevated IL-6 and TNF-alpha (>75th percentile) were, respectively, 1.95 (95% CI 1.56-2.44) and 1.88 (1.51-2.35) for diabetic participants and 1.51 (1.21-1.87) and 1.14 (0.92-1.42) for those with IFG/IGT after adjustment for age, sex, race, smoking, alcohol intake, education, and study site. Odds ratios for elevated CRP were 2.90 (2.13-3.95) and 1.45 (1.03-2.04) for diabetic women and men and 1.33 (1.07-1.69) for those with IFG/IGT regardless of sex. After adjustment for obesity, fat distribution, and inflammation-related conditions, IL-6 remained significantly related to both diabetes and IFG/IGT. CRP in women and TNF-alpha in both sexes were significantly related to diabetes, respectively, whereas risk estimates for IFG/IGT were decreased by adjustment for adiposity. Among diabetic participants, higher levels of HbA(1c) were associated with higher levels of all three markers of inflammation, but only CRP remained significant after full adjustment.

CONCLUSIONS

Our findings show that dysglycemia is associated with inflammation, and this relationship, although consistent in diabetic individuals, also extends to those with IFG/IGT.

The inflammatory C-reactive protein is increased in both liver and adipose tissue in severely obese patients independently from metabolic syndrome, Type 2 diabetes, and NASH

OBJECTIVE

C-Reactive Protein (CRP), a nonspecific marker of inflammation that is moderately elevated in obesity, metabolic syndrome (MS), and type 2 diabetes, has been proposed as a surrogate marker of nonalcoholic steatohepatitis (NASH). Its clinical usefulness in the diagnosis of NASH was evaluated in severely obese patients without or with MS, diabetes, and NASH and the potential roles of the liver and of the adipose tissue in CRP production were characterized.

METHODS

Severely obese patients without NASH (without MS [N = 13], with MS [N = 11], or with MS and diabetes [N = 7]) and with NASH (without [N = 8] or with [N = 7] MS) were studied. For each patient, liver and adipose tissue biopsies were collected during a bariatric surgery and were used to determine the CRP gene expression by real-time PCR. The role of interleukin-6 (IL6) and lipopolysaccharide in CRP expression was also evaluated in subcutaneous adipose tissue obtained during cosmetic abdominoplasty.

RESULTS

Plasma CRP levels were elevated in severely obese patients independently from the presence or absence of MS, diabetes, or NASH. CRP gene expression was not only increased in livers but also in adipose tissues of obese patients compared with controls subjects. In human adipose tissue, CRP mRNA levels were positively correlated with those of IL-6 and the CRP expression was enhanced in vitro by IL-6 and lipopolysaccharide.

CONCLUSION

Plasma CRP levels are not predictive of the diagnosis of NASH in severely obese patients. The liver but also the adipose tissue can produce CRP, a process which could be dependent on IL6. Therefore, both tissues might contribute to the elevated plasma CRP levels found in obesity. In addition, the large amount of body fat may well produce an important part of the circulating CRP, further limiting its clinical usefulness in the evaluation of NASH in severely obese patients.

Obesity is a major determinant of the association of C-reactive protein levels and the metabolic syndrome in type 2 diabetes

The inflammatory factor C-reactive protein (CRP) and the fibrinolytic variables fibrinogen and plasminogen activator-1 (PAI-1) are associated with long-term cardiovascular morbidity. To determine the contribution of body adiposity (BMI), insulin sensitivity (homeostasis model assessment of insulin resistance [HOMA-IR], and glycemia (HbA(1c) [A1C]) to the levels of these inflammatory and fibrinolytic variables in recently diagnosed (<or=3 years), drug-naive, type 2 diabetic subjects (fasting plasma glucose <or=10 mmol/l), we examined a representative subgroup (n = 921) of the U.S. cohort in ADOPT (A Diabetes Outcome Progression Trial). The relationship between levels of CRP, fibrinogen, PAI-1 antigen and PAI-1 activity, and baseline variables including National Cholesterol Education Program Adult Treatment Panel III metabolic syndrome phenotype were explored. All four factors increased significantly with increasing numbers of metabolic syndrome components (P = 0.0136 to P < 0.0001). BMI (P < 0.0001) and HOMA-IR (P < 0.0001) but not A1C (P = 0.65) increased with increasing numbers of metabolic syndrome components. Adjustment of CRP levels for BMI eliminated the association between CRP and the number of metabolic syndrome components, while adjusting for HOMA-IR did not (P = 0.0028). The relationships of PAI-1 antigen and PAI-1 activity with the number of metabolic syndrome components were maintained after adjusting for BMI (P = 0.0002 and P = <0.0001, respectively) or HOMA-IR (P = 0.0008 and P = <0.0001, respectively), whereas that with fibrinogen was eliminated after adjusting for BMI but not after adjusting for HOMA-IR (P = 0.013). Adjustment for A1C had no effect on any of the relationships between the inflammatory and fibrinolytic factors and the metabolic syndrome. We conclude that in recently diagnosed, drug-naive type 2 diabetic subjects, markers of inflammation and fibrinolysis are strongly related to the number of metabolic syndrome components. Further, for CRP and fibrinogen this relationship is determined by body adiposity and not by insulin sensitivity or glucose control.

Role of clotting factors and fibrin structure in predisposition to atherothrombotic disease

Atherothrombotic disease is a multifactorial disorder that develops secondary to a complex gene-environment interaction. The formation of an obstructive thrombus represents the final stage of the atherothrombotic process, and understanding the mechanisms involved in clot formation is essential in order to develop new preventive and therapeutic strategies aimed at decreasing mortality and morbidity from the disease. Studies have demonstrated an important correlation between final clot structure and predisposition to atherothrombotic disease. Both genetic and environmental factors contribute to the final ultrastructure of the clot, which, in turn, influences an individual's risk of the disease. This paper reviews the factors involved in determining clot structure. The role of commonly used therapeutic agents in modulating clot structure will also be discussed.

Blood glucose lowering by means of lifestyle intervention has different effects on adipokines as compared with insulin treatment in subjects with type 2 diabetes

AIMS/HYPOTHESIS

Adipokines may be important in mediating signals from adipocytes to insulin-sensitive tissue and vasculature. We studied the effect of different glucose-lowering therapies on serum levels of plasminogen activator inhibitor-1 (PAI-1), high-sensitivity C-reactive protein (hs-CRP), TNF-alpha, leptin, adiponectin and ghrelin in patients with type 2 diabetes.

SUBJECTS AND METHODS

Twenty-eight patients with poorly controlled type 2 diabetes who were receiving oral hypoglycaemic agents were allocated to one of the following groups, and treated for 1 year: (1) lifestyle intervention (L); (2) insulin treatment (I); and (3) combined treatment (L+I).

RESULTS

Similar improvements in glycaemic control occurred in all three groups. There was a reduction in body weight of 3.0 kg (median) (95% CI -5.9 to -2.0) in group L, whereas in groups L+I and I body weight increased by 3.5 kg (95% CI 1.5-4.9) and 4.9 kg (95% CI -3.1 to 8.2), respectively. By trend analyses, group L had reduced levels of PAI-1 (p=0.002), hs-CRP (p<0.0001) and TNF-alpha (p=0.006), while no significant changes were observed in the levels of leptin or adiponectin. In group I, the median levels of PAI-1 (p=0.008), TNF-alpha (p=0.058) and leptin (p=0.004) increased. In the L+I group there was a reduction in PAI-1 levels (p=0.014) and an increase in levels of leptin (p<0.001). The differences in changes in the levels of PAI-1, hs-CRP, TNF-alpha and leptin between groups were also significant (all p<0.01).

CONCLUSIONS/INTERPRETATION

Improvement of glycaemic control through lifestyle intervention in type 2 diabetes had more beneficial effects on adipokine levels than when the same lowering of HbA(1c) was achieved with insulin treatment.

Implications of Rosiglitazone and Pioglitazone on Cardiovascular Risk in Patients with Type 2 Diabetes Mellitus

Clinical data suggest that thiazolidinediones--specifically, rosiglitazone and pioglitazone--may improve cardiovascular risk factors through multiple mechanisms. Low insulin sensitivity has been described as an independent risk factor for coronary artery disease and cerebrovascular disease. Patients with insulin resistance often have several known risk factors, such as obesity, dyslipidemia, and hypertension. Other emerging risk factors may be prevalent in patients with insulin resistance, such as hyperinsulinemia, elevated C-reactive protein, elevated plasminogen activator inhibitor levels, and small, dense, low-density lipoproteins. The only available drug class that primarily targets insulin resistance is the thiazolidinediones. These drugs have shown efficacy in affecting surrogate markers of cardiovascular risk in patients with diabetes mellitus. Alterations in these risk factors are likely due to their effects on improving insulin sensitivity and/or glycemic control. Trials to assess whether thiazolidinediones actually reduce cardiovascular outcomes are continuing.

"Anti-inflammatory" drugs and their effects on type 2 diabetes

There is a growing body of evidence for the role of inflammation in type 2 diabetes. In addition to the evidence presented elsewhere, evidence is emerging that many drugs that have apparent "anti-inflammatory" properties may reduce the incidence and/or delay the onset of type 2 diabetes. Statins have been found to lower inflammatory markers, and a post hoc analysis of the West of Scotland Coronary Prevention Study (WOSCOPS) suggested that pravastatin may reduce the risk of developing diabetes, although the Lipid Lowering Arm of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) found no statistically significant effect of atorvastatin on risk of developing diabetes. Fibrates have been found to lower some markers of inflammation, and a prospective trial found that bezafibrate reduces risk of developing diabetes. Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers appear to reduce some markers of inflammation, and a meta-analysis concluded that ACE inhibitors and angiotensin receptor blockers reduce risk of developing type 2 diabetes. Metformin is known to reduce the risk of developing diabetes, and more recent evidence suggests it also lowers C-reactive protein, in part because of its modest weight-reducing effect. Thiazolidinediones reduce risk of developing diabetes, and consistently lower inflammatory markers independent of adiposity effects. High-dose aspirin inhibits cyclooxygenase and IkappaB kinase-beta and reduces fasting plasma glucose concentration, although there has not, as yet, been a large-scale trial to examine the effect of aspirin on the risk of developing diabetes. We conclude that although many drugs with potential anti-inflammatory properties reduce the risk of developing diabetes, it is difficult to prove that such anti-inflammatory properties contribute to their diabetes prevention since nearly all drugs have other, often more pronounced, actions. Studies with more specific inhibitors of inflammatory pathways (e.g., interleukin- 6 blockers) and mendelian randomization (genetic studies) will help determine whether targeting the inflammation axis is a fertile mechanism to treat or prevent type 2 diabetes.

High-sensitivity C-reactive protein as cardiovascular risk marker in patients with diabetes mellitus

C-reactive protein (CRP) is a liver-derived pattern recognition molecule that is increased in inflammatory states. It rapidly increases within hours after tissue injury, and it is suggested that it is part of the innate immune system and contributes to host defense. Since cardiovascular disease is at least in part an inflammatory process, CRP has been investigated in the context of arteriosclerosis and subsequent vascular disorders. Based on multiple epidemiological and intervention studies, minor CRP elevation [high-sensitivity CRP (hsCRP)] has been shown to be associated with future major cardiovascular risk (hsCRP:<1 mg/L=low risk; 1-3 mg/L=intermediate risk; 3-10 mg/L=high risk; >10 mg/L=unspecific elevation). It is recommended by the American Heart Association that patients at intermediate or high risk of coronary heart disease may benefit from measurement of hsCRP with regard to their individual risk prediction. Elevation of hsCRP is associated with increased risk of type 2 diabetes development in patients with all levels of metabolic syndrome. In type 1 and type 2 diabetes mellitus, hemoglobin A1c significantly correlates with hsCRP levels and future cardiovascular risk. Also, hsCRP levels increase with the stage of beta-cell dysfunction and insulin resistance. Non-diabetes drugs that have been shown to reduce hsCRP concentrations include aspirin, statins, cyclooxygenase-2 inhibitors, and fibrates. Recent intervention studies have also demonstrated the distinct efficacy of different anti-diabetes treatments on a variety of cardiovascular risk markers. Intensive insulin therapy may reduce inflammation, but this effect may be influenced by the degree of weight gain. Treatment with peroxisome proliferator-activated receptor gamma has lead to substantial reduction of hsCRP and other cardiovascular risk markers in several comparator studies. Since this effect was shown to be independent of the degree of glycemic improvement, it can be regarded as a classspecific effect. Whether these findings translate into a reduction of overall cardiovascular mortality will soon be shown by the currently running thiazolidinedione outcome studies. Positive results in these trials will further strengthen the value and acceptance of hsCRP, which is recommended as a predictive laboratory marker for cardiovascular disease risk also in patients with diabetes mellitus.

An immune origin of type 2 diabetes?

Subclinical, low-grade systemic inflammation has been observed in patients with type 2 diabetes and in those at increased risk of the disease. This may be more than an epiphenomenon. Alleles of genes encoding immune/inflammatory mediators are associated with the disease, and the two major environmental factors the contribute to the risk of type 2 diabetes-diet and physical activity-have a direct impact on levels of systemic immune mediators. In animal models, targeting of immune genes enhanced or suppressed the development of obesity or diabetes. Obesity is associated with the infiltration and proinflammatory activity of macrophages in adipose tissue, and immune mediators may be important regulators of insulin resistance, mitochondrial function, ectopic lipid storage and beta cell dysfunction or death. Intervention studies targeting these pathways would help to determine the contribution of an activated innate immune system to the development of type 2 diabetes.

Effect of intensive glycemic control on levels of markers of inflammation in type 1 diabetes mellitus in the diabetes control and complications trial

BACKGROUND

Type 1 diabetes mellitus is associated with an increased risk of cardiovascular disease (CVD) that is not fully explained by conventional risk factors. The Diabetes Control and Complications Trial (DCCT) showed that intensive diabetes therapy reduced levels of LDL cholesterol and triglycerides but increased the risk of major weight gain, which might adversely affect CVD risk. The present study examined the effect of intensive therapy on levels of several markers of inflammation that have been linked to risk of CVD.

METHODS AND RESULTS

We measured levels of inflammatory biomarkers in stored baseline and 3-year follow-up serum specimens from a random sample of 385 participants in the DCCT, a multicenter trial in which 1441 subjects aged 13 to 39 years with type 1 diabetes mellitus were randomized to intensive or conventional diabetes treatment. The markers included high-sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecule type 1 (sICAM-1), soluble vascular cell adhesion molecule type 1 (sVCAM-1), and the 55-kDa soluble tumor necrosis factor-alpha receptor 1 (sTNF-R1). We examined the effect of intensive therapy on the change in levels of the inflammatory markers. In unadjusted analyses, levels of hsCRP and sTNF-R1 increased in both treatment groups after 3 years of follow-up, with no significant difference between groups for hsCRP (P=0.53) but with a greater increase of sTNF-R1 in the intensive therapy group (P=0.002). In contrast, mean levels of sICAM-1 and sVCAM-1 decreased among participants assigned to intensive therapy, whereas they did not change among those in the conventional treatment group (P=0.03 for sICAM-1; P=0.03 for sVCAM-1). After adjustment for baseline levels and other factors, intensive therapy remained associated with a significant decrease in sICAM-1 (P=0.02) and an increase in sTNF-R1 (P=0.03). For hsCRP, there was a significant interaction between the top third of weight gain and treatment assignment (P=0.03). In subgroup analyses among subjects undergoing intensive therapy, hsCRP levels increased among those who gained the most weight, whereas it decreased among those in the bottom third of weight gain (P=0.0004).

CONCLUSIONS

Intensive therapy in patients with type 1 diabetes mellitus reduced levels of sICAM-1 and increased levels of sTNF-R1 and of hsCRP among those who gained weight. These data demonstrate that the effect of intensive therapy on inflammation is complex and, to the extent that hsCRP is a risk factor, suggest that the risk of atherosclerosis among diabetic patients may be influenced by the degree of weight gain while undergoing intensive therapy.

The effect of multi-factorial intervention on plasma von Willebrand factor, soluble E-selectin and tissue factor in diabetes mellitus: implications for atherosclerotic vascular disease

BACKGROUND

Endothelial abnormalities and a hypercoagulable state may contribute to increased cardiovascular risk in diabetes mellitus, particularly in patients with overt cardiovascular disease (CVD). We sought to determine the effect of intensified multi-factorial cardiovascular risk intervention on indices of endothelial abnormality and hypercoagulability in diabetes, and if patients with overt CVD would derive similar benefit as those without.

PATIENTS AND METHODS

We measured plasma von Willebrand factor (vWf, an index of endothelial damage/dysfunction), soluble E-selectin (sE-sel, marking endothelial activation) and tissue factor (TF, an initiator of coagulation) by ELISA in 94 patients with diabetes mellitus (38 with CVD and 56 without overt CVD) and 34 comparable controls. Thirty-three patients with CVD and 31 without overt CVD then participated in multi-factorial cardiovascular risk intervention over 1 year.

RESULTS

Plasma levels of vWf (P = 0.009), sE-sel (P < 0.001) and TF (P < 0.001) were significantly higher in diabetic patients compared with controls, with TF highest in patients with overt CVD. Intensive multi-factorial intervention resulted in reductions in glycated haemoglobin (HbA(1c)), total and LDL-cholesterol (all P < 0.05), but no significant weight change. This was associated with reductions in vWf in patients with (by 26%P = 0.003), and without (by 47%, P < 0.001), overt CVD. TF was reduced only in patients without overt CVD (by 45%, P < 0.001). There were no significant changes in sE-sel levels in either group.

CONCLUSION

Endothelial abnormalities in diabetes are only partially influenced by contemporary intensified multi-factorial cardiovascular risk intervention. These data suggest the need for earlier and more aggressive risk factor intervention.

Mechanisms, Significance and Treatment of Vascular Dysfunction in Type 2 Diabetes Mellitus

Endothelial dysfunction and increased arterial stiffness occur early in the pathogenesis of diabetic vasculopathy. They are both powerful independent predictors of cardiovascular risk. Advances in non-invasive methodologies have led to widespread clinical investigation of these abnormalities in diabetes mellitus, generating a wealth of new knowledge concerning the mechanisms of vascular dysfunction, risk factor associations and potential treatment targets. Endothelial dysfunction primarily reflects decreased availability of nitric oxide (NO), a critical endothelium-derived vasoactive factor with vasodilatory and anti-atherosclerotic properties. Techniques for assessing endothelial dysfunction include ultrasonographic measurement of flow-mediated vasodilatation of the brachial artery and plethysmography measurement of forearm blood flow responses to vasoactive agents. Arterial stiffness may be assessed using pulse wave analysis to generate measures of pulse wave velocity, arterial compliance and wave reflection. The pathogenesis of endothelial dysfunction in type 2 diabetes is multifactorial, with principal contributors being oxidative stress, dyslipidaemia and hyperglycaemia. Elevated blood glucose levels drive production of reactive oxidant species (ROS) via multiple pathways, resulting in uncoupling of mitochondrial oxidative phosphorylation and endothelial NO synthase (eNOS) activity, reducing NO availability and generating further ROS. Hyperglycaemia also contributes to accelerated arterial stiffening by increasing formation of advanced glycation end-products (AGEs), which alter vessel wall structure and function. Diabetic dyslipidaemia is characterised by accumulation of triglyceride-rich lipoproteins, small dense low-density lipoprotein (LDL) particles, reduced high-density lipoprotein (HDL)-cholesterol and increased postprandial free fatty acid flux. These lipid abnormalities contribute to increasing oxidative stress and may directly inhibit eNOS activity. Although lipid-regulating agents such as HMG-CoA reductase inhibitors (statins), fibric acid derivatives (fibrates) and fish oils are used to treat diabetic dyslipidaemia, their impact on vascular function is less clear. Studies in type 2 diabetes have yielded inconsistent results, but this may reflect sampling variation and the potential over-riding influence of oxidative stress, dysglycaemia and insulin resistance on endothelial dysfunction. Results of positive intervention trials suggest that improvement in vascular function is mediated by both lipid and non-lipid mechanisms, including anti-inflammatory, anti-oxidative and direct effects on the arterial wall. Other treatments, such as renin-angiotensin-aldosterone system antagonists, insulin sensitisers and lifestyle-based interventions, have shown beneficial effects on vascular function in type 2 diabetes. Novel approaches, targeting eNOS and AGEs, are under development, as are new lipid-regulating therapies that more effectively lower LDL-cholesterol and raise HDL-cholesterol. Combination therapy may potentially increase therapeutic efficacy and permit use of lower doses, thereby reducing the risk of adverse drug effects and interactions. Concomitant treatments that specifically target oxidative stress may also improve endothelial dysfunction in diabetes. Vascular function studies can be used to explore the therapeutic potential and mechanisms of action of new and established interventions, and provide useful surrogate measures for cardiovascular endpoints in clinical trials.

The role of insulin and the adipocytokines in regulation of vascular endothelial function

Vascular integrity in the healthy endothelium is maintained through the release of a variety of paracrine factors such as NO (nitric oxide). Endothelial dysfunction, characterized by reduced NO bioavailability, is associated with obesity, insulin resistance and Type II diabetes. Insulin has been demonstrated to have direct effects on the endothelium to increase NO bioavailability. Therefore altered insulin signalling in the endothelium represents a candidate mechanism underlying the association between insulin resistance and endothelial dysfunction. In recent years, it has become apparent that insulin sensitivity is regulated by the adipocytokines, a group of bioactive proteins secreted by adipose tissue. Secretion of adipocytokines is altered in obese individuals and there is increasing evidence that the adipocytokines have direct effects on the vascular endothelium. A number of current antidiabetic strategies have been demonstrated to have beneficial effects on endothelial function and to alter adipocytokine concentrations in addition to their effects on glucose homoeostasis. In this review we will explore the notion that the association between insulin resistance and endothelial dysfunction is accounted for by adipocytokine action on the endothelium. In addition, we examine the effects of weight loss, exercise and antidiabetic drugs on adipocytokine availability and endothelial function.

Insulin monotherapy versus combinations of insulin with oral hypoglycaemic agents in patients with type 2 diabetes mellitus

BACKGROUND

It is unclear whether patients with type 2 diabetes who have poor glycaemic control despite maximal oral hypoglycaemic agents (OHAs) should be commenced on insulin as monotherapy, or insulin combined with oral hypoglycaemic agents (insulin-OHA combination therapy).

OBJECTIVES

To assess the effects of insulin monotherapy versus insulin-OHA combinations therapy.

SEARCH STRATEGY

Eligible studies were identified by searching MEDLINE, EMBASE, and The Cochrane Library. Date of last search: May 2004.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with 2 months minimum follow-up duration comparing insulin monotherapy (all schemes) with insulin-OHA combination therapy.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of study quality were undertaken by three reviewers in pairs.

MAIN RESULTS

Twenty RCTs (mean trial duration 10 months) including 1,811 participants, with mean age 59.8 years and mean known duration of diabetes 9.6 years. Overall, study methodological quality was low. Twenty-eight comparisons in 20 RCTs were ordered according to clinical considerations. No studies assessed diabetes-related morbidity, mortality or total mortality. From 13 studies (21 comparisons), sufficient data were extracted to calculate pooled effects on glycaemic control. Insulin-OHA combination therapy had statistically significant benefits on glycaemic control over insulin monotherapy only when the latter was applied as a once-daily injection of NPH insulin. Conversely, twice-daily insulin monotherapy (NPH or mixed insulin) provided superior glycaemic control to insulin-OHA combination therapy regimens where insulin was administered as a single morning injection. In more conventional comparisons, regimens utilising OHAs with bedtime NPH insulin provided comparable glycaemic control to insulin monotherapy (administered as twice daily, or multiple daily injections). Overall, insulin-OHA combination therapy was associated with a 43% relative reduction in total daily insulin requirement compared to insulin monotherapy. Of the 14 studies (22 comparisons) reporting hypoglycaemia, 13 demonstrated no significant difference in the frequency of symptomatic or biochemical hypoglycaemia between insulin and combination therapy regimens. No significant differences in quality of life related issues were detected. Combination therapy with bedtime NPH insulin resulted in statistically significantly less weight gain compared to insulin monotherapy, provided metformin was used +/-sulphonylurea. In all other comparisons no significant differences with respect to weight gain were detected.

REVIEWERS' CONCLUSIONS

Bedtime NPH insulin combined with oral hypoglycaemic agents provides comparable glycaemic control to insulin monotherapy and is associated with less weight gain if metformin is used.

The postprandial state does not impair endothelial function in women with type 2 diabetes irrespective of glycaemic control

AIMS/HYPOTHESIS

The postprandial state has been shown to be associated with endothelial dysfunction, a predictor of cardiovascular morbidity. In type 2 diabetes, postprandial metabolic excursions are prolonged and exaggerated, but less pronounced if glycaemic control is optimised. We investigated the impact of improved glycaemic control on endothelial function in the postprandial state.

METHODS

We studied 19 postmenopausal women with type 2 diabetes and ten non-diabetic subjects. Participants with diabetes were re-studied 3 months after intensive glucose regulation. We measured forearm blood flow by strain gauge plethysmography during rest, during acetylcholine infusion and post ischaemia in the fasting state, and again 3 hours after a mixed meal (660 kcal, 55% fat).

RESULTS

Endothelium-dependent vasodilation was impaired in the diabetic group (p<0.005) and improved following an HbA1c reduction of 0.96% (p<0.05 for high-dose acetylcholine infusion). Postprandial metabolic excursions were higher in the diabetic group (p<0.001, p<0.01 and p<0.05 for glucose, insulin and triglycerides respectively). Resting forearm blood flow increased in all groups after the meal (p<0.005). There was no difference in fasting and postprandial endothelium-dependent vasodilation before and after improved glucose regulation in either group.

CONCLUSIONS/INTERPRETATION

The postprandial state does not impair endothelial function in non-diabetic women and does not make pre-existing endothelial dysfunction worse in women with type 2 diabetes, irrespective of glycaemic control.

C-reactive protein, its role in inflammation, Type 2 diabetes and cardiovascular disease, and the effects of insulin-sensitizing treatment with thiazolidinediones

Increased concentrations of the marker of inflammation, C-reactive protein (CRP), are associated with insulin resistance, Type 2 diabetes and the development of cardiovascular disease. In particular, inflammation is closely associated with endothelial dysfunction and is recognized as one of the cardiovascular risk factors clustering in the Insulin Resistance Syndrome or Metabolic Syndrome. The exact mechanisms linking insulin resistance and inflammation remain unclear. However, the close association between insulin resistance and inflammation in atherogenesis suggests that therapies that address both parameters may have benefits in reducing diabetes-related macrovascular complications. The thiazolidinedione class of oral anti-diabetic agents are powerful insulin sensitizers that also have anti-inflammatory properties. Treatment with these agents has a range of anti-atherogenic effects, including reduced levels of CRP, plasminogen activator inhibitor-1 (PAI-1), TNF-alpha and reactive oxygen species. Additionally, the insulin-sensitizing effect of thiazolidinediones improves other factors of the Insulin Resistance Syndrome, including dyslipidaemia and hypertension. Outcome studies are underway to determine if the effects of improving insulin sensitivity and reducing inflammation will translate into clinical benefits and reduce the cardiovascular morbidity and mortality associated with insulin resistance and Type 2 diabetes.

Inflammation, insulin resistance, and adiposity: a study of first-degree relatives of type 2 diabetic subjects

OBJECTIVE

Inflammatory markers such as C-reactive protein (CRP) are associated with insulin resistance, adiposity, and type 2 diabetes. Whether inflammation causes insulin resistance or is an epiphenomenon of obesity remains unresolved. We aimed to determine whether first-degree relatives of type 2 diabetic subjects differ in insulin sensitivity from control subjects without a family history of diabetes, whether first-degree relatives of type 2 diabetic subjects and control subjects differ in CRP, adiponectin, and complement levels, and whether CRP is related to insulin sensitivity independently of adiposity.

RESEARCH DESIGN AND METHODS

We studied 19 young normoglycemic nonobese first-degree relatives of type 2 diabetic subjects and 22 control subjects who were similar for age, sex, and BMI. Insulin sensitivity (glucose infusion rate [GIR]) was measured by the euglycemic-hyperinsulinemic clamp. Dual-energy X-ray absorptiometry determined total and abdominal adiposity. Magnetic resonance imaging measured abdominal adipose tissue volumes.

RESULTS

First-degree relatives of type 2 diabetic subjects had a 20% lower GIR than the control group (51.8 +/- 3.9 vs. 64.9 +/- 4.6 micromol x min(-1) x kg fat-free mass(-1), P = 0.04). However, first-degree relatives of subjects with type 2 diabetes and those without a family history of diabetes had normal and comparable levels of CRP, adiponectin, and complement proteins. When the cohort was examined as a whole, CRP was inversely related to GIR (r = -0.33, P = 0.04) and adiponectin (r = -0.34, P = 0.03) and positively related to adiposity (P < 0.04). However, CRP was not related to GIR independently of fat mass. In contrast to C3 (r = 0.41, P = 0.009) and factor B (r = 0.43, P = 0.005), CRP was unrelated to factor D.

CONCLUSIONS

The insulin-resistant state is not associated with changes in inflammatory markers or complement proteins in subjects at high risk of type 2 diabetes. Our study confirms a strong relationship between CRP and fat mass. Increasing adiposity and insulin resistance may interact to raise CRP levels.

Initiation of insulin therapy reduces serum concentrations of high-sensitivity C-reactive protein in patients with type 2 diabetes

Atherosclerosis has highly important chronic inflammatory aspects. We investigated anti-inflammatory effects upon initiating insulin therapy by measuring serum high-sensitivity C-reactive protein (hsCRP) and plasma fibrinogen and serum monocyte chemoattractant protein (MCP)-1in patients with poorly controlled type 2 diabetes. In 18 inpatients with type 2 diabetes, we measured serum hsCRP, plasma fibrinogen, serum MCP-1, body weight (BW), girth, and fasting plasma glucose (FPG) before and 2 weeks (14.0 +/- 2.5 days) after initiation of insulin therapy. Daily insulin doses (in units) were approximately 0.2 x BW (in kilograms). Various changes (ratio) were calculated as the ratio of the value during treatment to the pretreatment value. Significant decreases occurred for log(10) hsCRP and FPG (-0.025 +/- 0.557 mg/L, 215 +/- 64.3 mg/dL v -0.213 +/- 0.571 mg/L, 129.8 +/- 32.1 mg/dL; P =.0121, and P =.00002, respectively). This was particularly true for log(10) hsCRP in patients whose BW was unchanged or increased between measurement (P =.0050). There were no significant differences between pretreatment and treatment values for fibrinogen and MCP-1. However, MCP-1 decreased significantly in the group with high-value in the first time point (MCP-1 > 250 pg/mL, n = 9; P =.0224) compared with the low-value group (MCP-1 < 250 pg/mL, n = 9; P =.3164). No significant correlation was found between hsCRP ratio and fibrinogen ratio, MCP-1 ratio, BW ratio, waist girth ratio, or FPG ratio. In conclusion, newly initiated insulin therapy in patients with poorly controlled type 2 diabetes decreased serum hsCRP. The decrease in hsCRP may have resulted largely from anti-inflammatory effects of insulin.

Effect of Insulin Therapy on Nonglycemic Variables During Acute Illness

OBJECTIVE

To review the possible mechanisms for the reported clinical finding of better outcomes for hospitalized and critically ill patients as the result of improved metabolic control.

RESULTS

Insulin inhibits free fatty acids, proinflammatory cytokines, and inflammatory growth factors, all of which may be detrimental in critically ill patients. Furthermore, insulin enhances nitric oxide synthesis, which promotes vasodilation. The mechanisms of insulin regulation of these factors are complex, although insulin seems to have a direct effect on the transcriptional factor, nuclear factor-kappabeta (NF-kappabeta). In turn, NF-kappabeta modulates the proinflammatory cytokines, adhesion molecules, and chemokines. In a euglycemic or slightly hyperglycemic environment, NF-kappabeta is suppressed by insulin; however, with more profound hyperglycemia, NF-kappabeta is induced and the proinflammatory cytokines are thus increased.

CONCLUSION

Although considerable research must be completed to identify the apparent relationship between stringent metabolic control and improved outcomes in acutely ill patients, current evidence suggests that both the treatment (glucose-insulin-potassium infusion) and the resultant plasma glucose concentrations may be independent important components of the underlying mechanisms.

AMPK activation may suppress hepatic production of C-reactive protein by stimulating nitric oxide synthase

The utility of C-reactive protein (CRP) as an independent risk factor for vascular events may be attributable, at least in part, to a direct adverse impact of CRP on endothelial function. In particular, modestly elevated concentrations of CRP have been shown to decrease the expression of the endothelial isoform of nitric oxide synthase (eNOS) in endothelial cells; the implication of this for vascular health is evident. Strategies for decreasing elevated CRP include administration of statins, thiazolidinediones, and metformin; moderate alcohol consumption and appropriate weight loss are also helpful in this regard. Metformin's antidiabetic efficacy is now known to reflect activation of AMP-activated kinase (AMPK); AMPK can stimulate eNOS, which is expressed in hepatocytes. A recent study shows that nitric oxide suppresses the activation of Stat3 by interleukin-6 in hepatocytes; Stat3 is crucial for the IL-6-mediated induction of CRP and various other acute phase reactants. Thus, it is proposed that metformin--or AMPK---inhibits hepatic CRP production by boosting hepatic nitric oxide synthesis, which in turn impedes Stat3 activation and CRP transcription. This hypothesis should be readily testable in cultured hepatocytes. Although the impact of metformin on plasma IL-6 levels has not been reported, the possibility that AMPK activation could influence adipocyte secretion of this cytokine also merits scrutiny.

Insulin resistance and hyperglycemia in critical illness: role of insulin in glycemic control

Alterations in glucose metabolism, including hyperglycemia associated with insulin resistance, occur in critical illness. Acutely, such alterations result from normal, adaptive activation of endocrine responses, including increased release of catecholamines, cortisol, and glucagon and a reduced glucose uptake capacity. In prolonged critical illness, neuroendocrine changes lead to more extensive metabolic changes that may be associated with development of complications and poor prognosis. Until recently, hyperglycemia was not routinely controlled in intensive care units, except among patients with known diabetes mellitus. Studies have demonstrated that glycemic management in postmyocardial infarction in patients with diabetes is an effective practice. Recent investigation has extended this to demonstrate reduced morbidity and mortality in a surgical critically ill population with and without diabetes mellitus in later phases of critical illness. Although the mechanisms for improved patient outcomes need to be established, this novel approach to management of hyperglycemia in critical illness is a new and important concept for those working in critical care. This article reviews alterations in glucose metabolism which occur in critically ill patients and discusses potential mechanisms and mediators (e.g., hormones, cytokines) that may play a key role in hyperglycemia and insulin resistance during acute and prolonged phases of severe illness. The article addresses the application of insulin protocols and exogenous regulation of glucose concentration in critical illness based on a review of recent intervention studies.

Metabolic, endocrine, and immune effects of stress hyperglycemia in a rabbit model of prolonged critical illness

Stress hyperglycemia is frequent in critically ill patients. The aim of this study was to investigate the effect of blood glucose control with insulin on endocrine, metabolic, and immune function in an animal model of severe injury. Seventy-two hours after alloxan injection and exogenous insulin infusion combined with continuous iv parenteral nutrition, male New Zealand White rabbits received a burn injury and were allocated to a normoglycemic (n = 17) or hyperglycemic (n = 13) group. In the normoglycemic group, blood glucose levels were kept between 3.3 and 6.1 mmol/liter by insulin infusion, whereas in the hyperglycemic group blood glucose levels were maintained at 13.8-16.6 mmol/liter. Blood was drawn for biochemical analysis at regular time points. At 24 and 72 h after burn injury, immune function of monocytes was assessed in vitro. Maintenance of normoglycemia with exogenous insulin after severe trauma to a large extent prevented weight loss, lactic acidosis, and hyponatremia. Furthermore, within 3 d after injury, the intervention improved phagocytosis of monocytes investigated in fresh cells by more than a mean 150% (P = 0.006) and after 24-h incubation with or without lipopolysaccharide by more than a mean 4-fold (P = 0.001) and 2-fold (P = 0.05), respectively. Oxidative killing after 24-h incubation was also improved by 2-fold (P = 0.05), but no effect on chemotaxis was detected. Concomitantly, inflammation and stress-induced growth hormone hypersecretion were suppressed. Prevention of catabolism, acidosis, excessive inflammation, and impaired innate immune function may explain previously documented beneficial effects of intensive insulin therapy on outcome of critical illness.

Plasma interleukin-6 is associated with coagulation in poorly controlled patients with Type 2 diabetes

AIMS

We investigated the relationship between interleukin (IL)-6 and coagulation, i.e. whether changes in the plasma IL-6 are associated with those in coagulation markers (D dimer and fibrinogen) after glycaemic control with sulphonylurea or insulin in poorly controlled patients with Type 2 diabetes.

METHODS

We studied 42 patients with Type 2 diabetes, including 19 subsequently treated with sulphonylurea, 23 treated with insulin and 48 control subjects. All patients were in poor glycaemic control and were hospitalized for 3 weeks. At the beginning and end of treatment, we measured plasma concentrations of IL-6, fibrinogen, and D dimer.

RESULTS

Plasma concentrations of IL-6 and D dimer were significantly higher in diabetic patients than in controls (P<0.0001 for both). In all patients with diabetes, the plasma concentration of IL-6 decreased significantly (P<0.001) after treatment. Changes in the plasma IL-6 during hospitalization were positively correlated with those in plasma D dimer and fibrinogen (r=0.664, P<0.0001; r=0.472, P=0.0042, respectively). Treatment with sulphonylurea or insulin caused a similar fall in the plasma IL-6 concentration with a concomitant decrease in the BMI and an equal improvement in glycaemia.

CONCLUSIONS

In poorly controlled patients with Type 2 diabetes, plasma IL-6 concentrations were reduced significantly even by short-term metabolic control. As changes in the plasma concentrations of D dimer are related to plasma IL-6, plasma IL-6 may reflect a pro-coagulant as well as an inflammatory state in patients with Type 2 diabetes.

Diet and C-reactive protein

C-reactive protein (CRP) is an independent predictor of cardiovascular events in healthy individuals and those with pre-existing disease. It also probably contributes to the disease process. CRP levels are higher in obese subjects and this link is almost certainly because of increased insulin resistance. Interventions that alter insulin resistance, such as weight loss, exercise, and conjugated linoleic acid, also alter CRP. Glycemic load is associated with CRP, but there have been no interventions with altered macronutrient composition. In the context of weight loss, macronutrient composition is probably not important. Alcohol lowers CRP, but the mechanism is unknown. The interaction between gender and obesity needs further work, but it appears that obesity has a greater effect on CRP levels in women.

The potential role of peroxisome proliferator-activated receptors on inflammation in type 2 diabetes mellitus and atherosclerosis

Increasing attention has focused on the role of inflammation in various chronic diseases, including atherosclerosis. Recent compelling data have begun to unite work from various arenas, such as epidemiology and vascular biology, and even clinical trials to provide evidence for inflammation as a mechanism underlying cardiovascular disease. Inflammation has been implicated in the pathogenesis, progression, and complications of both atherosclerosis and diabetes mellitus-2 complex disorders often found intertwined in patients. Although this story continues to evolve, peroxisome proliferator-activated receptors (PPARs) have been implicated as a molecular pathway involved in both these disease processes. In vitro data, animal work, and some human studies suggest that synthetic PPAR agonists in clinical use, such as thiazolidinediones, may not only regulate metabolic processes but may also limit inflammatory responses, including some involved in atherosclerosis.

Insulin acutely increases fibrinogen production in individuals with type 2 diabetes but not in individuals without diabetes

Fibrinogen is an acute-phase reactant and an independent cardiovascular risk factor. Insulin without amino acid replacement acutely suppressed fibrinogen production in nondiabetic and type 1 diabetic individuals. Fibrinogen production and plasma concentration increase in insulin-resistant type 2 diabetes. It is not known whether altered response to insulin contributes to hyperfibrinogenemia in type 2 diabetes. Fibrinogen fractional (FSR) and absolute (ASR) synthesis rates were measured using a leucine isotopic model in type 2 diabetic men (n = 7; age = 51 +/- 3 years; BMI = 26.7 +/- 1 kg/m(2)) compared with matched nondiabetic subjects under basal conditions and following a 4-h euglycemic-, euaminoacidemic-hyperinsulinemic clamp. Basal fibrinogen concentration (+35%, P < 0.05) and ASR (+35%, P < 0.05) were greater in the diabetic subjects. Following clamp, fibrinogen FSR and ASR were unchanged in the control subjects. In contrast, fibrinogen FSR and ASR increased by 41 and 43%, respectively (P < 0.05), in the diabetic subjects. Thus, fibrinogen production is acutely increased by insulin when euglycemia and euaminoacidemia are maintained in type 2 diabetic individuals but not in nondiabetic individuals. Enhanced fibrinogen production by insulin is likely to be a key alteration contributing to hyperfibrinogenemia and therefore cardiovascular risk in type 2 diabetes. Unchanged fibrinogen production in nondiabetic individuals suggests a role of plasma amino acids in regulating fibrinogen production in humans.