High-Sensitivity C-Reactive Protein in Japanese Patients with Type 2 Diabetes

Role of Insulin in Neurotrauma and Neurodegeneration: A Review

Insulin is a hormone typically associated with pancreatic release and blood sugar regulation. The brain was long thought to be “insulin-independent,” but research has shown that insulin receptors (IR) are expressed on neurons, microglia and astrocytes, among other cells. The effects of insulin on cells within the central nervous system are varied, and can include both metabolic and non-metabolic functions. Emerging data suggests that insulin can improve neuronal survival or recovery after trauma or during neurodegenerative diseases. Further, data suggests a strong anti-inflammatory component of insulin, which may also play a role in both neurotrauma and neurodegeneration. As a result, administration of exogenous insulin, either via systemic or intranasal routes, is an increasing area of focus in research in neurotrauma and neurodegenerative disorders. This review will explore the literature to date on the role of insulin in neurotrauma and neurodegeneration, with a focus on traumatic brain injury (TBI), spinal cord injury (SCI), Alzheimer’s disease (AD) and Parkinson’s disease (PD).

Role of c-Jun N-terminal Kinase (JNK) in Obesity and Type 2 Diabetes

Obesity has been described as a global epidemic and is a low-grade chronic inflammatory disease that arises as a consequence of energy imbalance. Obesity increases the risk of type 2 diabetes (T2D), by mechanisms that are not entirely clarified. Elevated circulating pro-inflammatory cytokines and free fatty acids (FFA) during obesity cause insulin resistance and ß-cell dysfunction, the two main features of T2D, which are both aggravated with the progressive development of hyperglycemia. The inflammatory kinase c-jun N-terminal kinase (JNK) responds to various cellular stress signals activated by cytokines, free fatty acids and hyperglycemia, and is a key mediator in the transition between obesity and T2D. Specifically, JNK mediates both insulin resistance and ß-cell dysfunction, and is therefore a potential target for T2D therapy.

Do flavanols-rich natural products relieve obesity-related insulin resistance?

Growing evidence support that insulin resistance may occur as a severe problem due to chronic energetic overfeeding and subsequent obesity. When an abundance of glucose and saturated fat enter the cell, impaired blood flow, hypoxia, inflammation and macrophage infiltration in obese adipose tissue may induce oxidative stress and insulin resistance. Excessive circulating saturated fatty acids ectopically accumulate in insulin-sensitive tissues and impair insulin action. In this context, excessive hepatic lipid accumulation may play a central, pathogenic role in insulin resistance. It is thought that dietary polyphenols may ameliorate obesity-related insulin resistance by attenuating inflammatory responses and oxidative stress. The most often occurring natural polyphenolic compounds are flavonoids. In this review, the possible mechanistic effect of flavonoid-rich natural products on insulin resistance-related metabolic pathways is discussed. Polyphenol intake can prevent high-fat-diet-induced insulin resistance via cell surface G protein-coupled estrogen receptors by upregulating the expression of related genes, and their pathways, which are responsible for the insulin sensitivity.

Deficiency of intestinal mucin-2 protects mice from diet-induced fatty liver disease and obesity

Nonalcoholic fatty liver disease (NAFLD) and obesity are characterized by altered gut microbiota, inflammation, and gut barrier dysfunction. Here, we investigated the role of mucin-2 (Muc2) as the major component of the intestinal mucus layer in the development of fatty liver disease and obesity. We studied experimental fatty liver disease and obesity induced by feeding wild-type and Muc2-knockout mice a high-fat diet (HFD) for 16 wk. Muc2 deficiency protected mice from HFD-induced fatty liver disease and obesity. Compared with wild-type mice, after a 16-wk HFD, Muc2-knockout mice exhibited better glucose homeostasis, reduced inflammation, and upregulated expression of genes involved in lipolysis and fatty acid β-oxidation in white adipose tissue. Compared with wild-type mice that were fed the HFD as well, Muc2-knockout mice also displayed higher intestinal and plasma levels of IL-22 and higher intestinal levels of the IL-22 target genes Reg3b and Reg3g. Our findings indicate that absence of the intestinal mucus layer activates the mucosal immune system. Higher IL-22 levels protect mice from diet-induced features of the metabolic syndrome.

Novel phosphorylation of PPARγ ameliorates obesity-induced adipose tissue inflammation and improves insulin sensitivity

Chronic inflammation in adipose tissue is highly associated with insulin resistance. Herein, we demonstrate that a novel modification of PPARγ is strongly associated with inflammatory responses in adipose tissue. c-Src kinase directly phosphorylated PPARγ at Tyr78, and this process was reversed by protein tyrosine phosphatase-1B (PTP-1B). In adipocytes, phosphorylation of PPARγ suppressed the expression of pro-inflammatory genes as well as the secretion of chemokines and cytokines, thus reducing macrophage migration. Importantly, pharmacological inhibition of c-Src kinase aggravated insulin resistance in obese mice with a concomitant increase in the expression of pro-inflammatory genes in adipose tissue. These data strongly suggest that PPARγ phosphorylation is the key regulatory mechanism of the inflammatory response in adipose tissue, which is highly associated with glucose tolerance and insulin sensitivity. Furthermore, these data increase our understanding of the mechanical aspects of developing novel anti-diabetic drugs targeting PPARγ phosphorylation.

GDF15 Is a Novel Biomarker for Impaired Fasting Glucose

BACKGROUND

Growth differentiation factor-15 (GDF15) is a protein that belongs to the transforming growth factor β superfamily. An elevated serum level of GDF15 was found to be associated with type 2 diabetes mellitus (T2DM). T2DM is an inflammatory disease that progresses from normal glucose tolerance (NGT) to impaired fasting glucose (IFG). Hence, we aimed to validate the relationship between GDF15 and IFG.

METHODS

The participants were divided into the following three groups: NGT (n=137), IFG (n=29), and T2DM (n=75). The controls and T2DM outpatients visited the hospital for routine health check-ups. We used fasting blood glucose to detect IFG in nondiabetic patients. We checked the body mass index (BMI), C-reactive protein level, metabolic parameters, and fasting serum GDF15 level.

RESULTS

Age, BMI, triglyceride, insulin, glucose, homeostatic model assessment-insulin resistance (HOMA-IR), and GDF15 levels were elevated in the IFG and T2DM groups compared to the NGT group. In the correlation analysis between metabolic parameters and GDF15, age and HOMA-IR had a significant positive correlation with GDF15 levels. GDF15 significantly discriminated between IFG and NGT, independent of age, BMI, and HOMA-IR. The serum levels of GDF15 were more elevated in men than in women. As a biomarker for IFG based on the receiver operating characteristic curve analysis, the cutoff value of GDF15 was 510 pg/mL in males and 400 pg/mL in females.

CONCLUSION

GDF15 had a positive correlation with IR independent of age and BMI, and the serum level of GDF15 was increased in the IFG and T2DM groups. GDF15 may be a novel biomarker for detecting IFG in nondiabetic patients.

A Prospective Study of Variability in Glycemic Control during Different Phases of the Menstrual Cycle in Type 2 Diabetic Women Using High Sensitivity C - Reactive Protein

INTRODUCTION

Diabetes mellitus (DM) is one of the metabolic syndromes prevalent worldwide, with more concentration in the Asian region. Many studies have been conducted in order to understand the complex pathogenesis of this disease. Yet, there exists a lacuna in our knowledge about DM. This study aims at establishing the reason for glycemic variation in menstruating Type-2 diabetic women by estimation of C-reactive protein, an inflammatory marker that exhibits significant association with changes in blood glucose levels.

METHODOLOGY

A prospective study was undertaken in Type-2 diabetic women of reproductive age group to assess the variability of glycemic control during different phases of menstrual cycle using high sensitivity C reactive protein (hs-CRP) as the biomarker. Fifty women were enrolled after satisfying a set of inclusion and exclusion criteria. The fasting blood glucose, hs-CRP concentration and endogenous female hormones were assayed in follicular and luteal phases of the cycle. The observed parameters were analyzed statistically for significant correlation. Observation and Result: The result showed that hs-CRP level significantly correlates with increasing levels of fasting blood glucose level in both the phases of menstrual cycle in Type-2 diabetic women. The significance is statistically stronger during luteal phase of the cycle (r = 0.807; p<0.05). The correlation observed between hs-CRP and Estrodiol in follicular phase (r = -0.311; p < 0.05) was not statistically significant. The hs-CRP level increased significantly with progesterone level during luteal phase (r = 0.826; p <0.05).

CONCLUSION

This study concludes that Type-2 diabetic women of reproductive age group encounter a period of poor glycemic control during luteal phase, as shown by statistically high hs-CRP level mediated by endogenous progesterone hormone. Therefore, this study advocates careful monitoring, life style adjustments and drug regime to reduce the fluctuation in glycemic level experienced by Type-2 diabetic premenopausal women in the luteal phase.

Effects of Phyllanthus emblica extract on endothelial dysfunction and biomarkers of oxidative stress in patients with type 2 diabetes mellitus: a randomized, double-blind, controlled study

BACKGROUND

It has been reported that hyperglycemia can induce endothelial dysfunction via increased oxidative stress and that it plays a central role in the development of atherosclerosis and coronary heart disease. Phyllanthus emblica (Emblica officinalis, amla) is known for its antioxidant and antihyperlipidemic activity. The present study compared the effects of an aqueous extract of P. emblica (highly standardized by high-performance liquid chromatography to contain low molecular weight hydrolyzable tannins, ie, emblicanin A, emblicanin B, pedunculagin, and punigluconin) versus those of atorvastatin and placebo on endothelial dysfunction and biomarkers of oxidative stress in patients with type 2 diabetes.

METHODS

Eligible patients were randomized to receive either P. emblica 250 mg twice daily, P. emblica 500 mg twice daily, atorvastatin 10 mg in the evening and matching placebo in the morning, or placebo twice daily for 12 weeks. The primary efficacy parameter was the change in endothelial function identified on salbutamol challenge at baseline and after 12 weeks of treatment. Secondary efficacy parameters were changes in biomarkers of oxidative stress (malondialdehyde, nitric oxide, and glutathione), high sensitivity C-reactive protein levels, the lipid profile, and glycosylated hemoglobin (HbA1c) levels. Laboratory safety parameters were measured at baseline and after 12 weeks of treatment.

RESULTS

Eighty patients completed the study. Treatment with P. emblica 250 mg, P. emblica 500 mg, or atorvastatin 10 mg produced significant reductions in the reflection index (-2.25%±1.37% to -9.13%±2.56% versus -2.11%±0.98% to -10.04%±0.92% versus -2.68%±1.13% to -11.03%±3.93%, respectively), suggesting improvement in endothelial function after 12 weeks of treatment compared with baseline. There was a significant improvement in biomarkers of oxidative stress and systemic inflammation compared with baseline and placebo. Further, the treatments significantly improved the lipid profile and HbA1c levels compared with baseline and placebo. All treatments were well tolerated.

CONCLUSION

Both atorvastatin and P. emblica significantly improved endothelial function and reduced biomarkers of oxidative stress and systemic inflammation in patients with type 2 diabetes mellitus, without any significant changes in laboratory safety parameters.

Macrophages, inflammation, and insulin resistance

Obesity induces an insulin-resistant state in adipose tissue, liver, and muscle and is a strong risk factor for the development of type 2 diabetes mellitus. Insulin resistance in the setting of obesity results from a combination of altered functions of insulin target cells and the accumulation of macrophages that secrete proinflammatory mediators. At the molecular level, insulin resistance is promoted by a transition in macrophage polarization from an alternative M2 activation state maintained by STAT6 and PPARs to a classical M1 activation state driven by NF-kappaB, AP1, and other signal-dependent transcription factors that play crucial roles in innate immunity. Strategies focused on inhibiting the inflammation/insulin resistance axis that otherwise preserve essential innate immune functions may hold promise for therapeutic intervention.

Variation of fasting serum C-peptide level after admission in Japanese patients with type 2 diabetes mellitus

BACKGROUND

The aim of this study was to evaluate the variation of fasting serum C-peptide (S-CPR) levels, as a marker for endogenous insulin secretion after admission in Japanese patients with type 2 diabetes mellitus (T2DM).

METHODS

S-CPR levels together with other metabolic factors were measured in 234 T2DM patients twice: at the beginning and at the end of admission for the control of blood sugar levels. As a result, patients were classified into two groups according to their changes of S-CPR (DeltaS-CPR), which consisted of patients whose S-CPR levels had decreased (group D) and increased (group I) after admission.

RESULTS

Patients allocated to group I showed younger age, shorter duration of diabetes, and lower basal S-CPR level compared to group D. Conversely, patients in group D showed higher levels of high-sensitivity C-reactive protein (HS-CRP) and brachial-ankle pulse wave velocity compared to group I, suggesting patients in this group are prone to atherosclerosis. DeltaS-CPR was positively correlated with the change of body mass index, waist circumference, and triglycerides in group D. On the other hand, DeltaS-CPR was negatively correlated with the change of HS-CRP in group I, indicating residual beta-cell function could be recovered by the amelioration of inflammatory status in pancreatic islets.

CONCLUSIONS

It is plausible that Japanese T2DM patients could be classified according to the variation of S-CPR after admission. Evaluation of basal and the variation of S-CPR could provide advantageous information for the management of diabetes mellitus or related disorders.

Attenuated metabolic effect of waist measurement in Japanese female patients with type 2 diabetes mellitus

Waist circumference (WC) was measured in 200 Japanese patients with type 2 diabetes mellitus (T2DM: male 106, female 94, mean age 61 years old) who had been admitted in our hospital, and relationship with various risk factors to predict future cardiovascular disease (CVD) was analyzed. There was a positive and statistically significant trend in WC levels with an increasing number of CVD risk factors in male patients, whereas no significant trend of WC was observed in female patients. The receiver operator characteristic (ROC) curve for WC to predict the presence of two or more risk factors of CVD depicted greater area under the curve in male patients (0.732) than that in female patients (0.571). Apart from positive correlation with fasting serum C-peptide (S-CPR) and log-transformed high-sensitivity C-reactive protein (log HS-CRP) in both genders, WC was positively correlated with log-transformed triglyceride (log TG), systolic and diastolic blood pressure (SBP and DBP) and negatively with HDL-cholesterol (HDL-C) in male patients, whereas it was negatively correlated with HbA1c and fasting plasma glucose (FPG) in female patients. The change of WC after administration (DeltaWC) was correlated with DeltaS-CPR, DeltaLDL-C, DeltaSBP and DeltaDBP in male patients, while no relationship was observed in female patients. In conclusion, WC is a reliable marker to predict future CVD events at least in Japanese male, but not female patients with T2DM.

Aggravation of albuminuria by metabolic syndrome in type 2 diabetic Asian subjects

AIMS

We investigated the relationship of urinary albumin excretion (UAE) to metabolic syndrome and type 2 diabetes in Asian.

METHODS

A total of 446 subjects (187 without diabetes and 259 with type 2 diabetes) were enrolled in this study. The components of metabolic syndrome, high sensitivity C-reactive protein (hs-CRP) and UAE were assessed. Based on metabolic syndrome and diabetes status, participants were categorized into one of the following groups: neither metabolic syndrome nor diabetes (MS-DM-), metabolic syndrome without diabetes (MS+DM-), diabetes without metabolic syndrome (MS-DM+) and both metabolic syndrome and diabetes (MS+DM+).

RESULTS

The UAE in the MS+DM- group was higher than that in the MS-DM- group (P<0.001) and lower than that in the MS+DM+ group (P<0.001), but not significantly different from that in the MS-DM+ group (P=0.349). The trend of increasing UAE in these four groups was independent of hs-CRP.

CONCLUSION

UAE was lowest in subjects with neither metabolic syndrome nor diabetes and highest in subjects with both metabolic syndrome and type 2 diabetes; however, there was no significant difference between the metabolic syndrome alone group and the type 2 diabetes alone group.

Effects of aspirin on serum C-reactive protein and interleukin-6 levels in patients with type 2 diabetes without cardiovascular disease: a randomized placebo-controlled crossover trial

AIM

Low-grade inflammation plays a pivotal role in atherogenesis in type 2 diabetes. Next to its antithrombotic effects, several lines of evidence demonstrate anti-inflammatory properties of aspirin. We determined the effects of aspirin on inflammation - represented by C-reactive protein (CRP) and interleukin-6 (IL-6) - in type 2 diabetic subjects without cardiovascular disease and assessed differential effects of aspirin 300 mg compared with 100 mg.

METHODS

A randomized, placebo-controlled, double-blind, crossover trial was performed in 40 type 2 diabetic patients. In two periods of 6 weeks, patients used 100 or 300 mg aspirin and placebo. Plasma CRP and IL-6 levels were measured before and after both periods.

RESULTS

Use of aspirin resulted in a CRP reduction of 1.23 +/- 1.02 mg/l (mean +/- s.e.m.), whereas use of placebo resulted in a mean increase of 0.04 +/- 1.32 mg/l (P = 0.366). Aspirin reduced IL-6 with 0.7 +/- 0.5 pg/ml, whereas use of placebo resulted in a mean increase of 0.2 +/- 0.8 pg/ml (P = 0.302). There were no significant differences in effects on CRP and IL-6 between 100 and 300 mg aspirin.

CONCLUSIONS

Our results indicate that a 6-week course of aspirin does not improve low-grade inflammation in patients with type 2 diabetes without cardiovascular disease, although a modest effect could not be excluded. No significant differential effects between aspirin 100 and 300 mg were found.

Carotid intima-media thickness and markers of inflammation, endothelial damage and hemostasis

BACKGROUND

Different soluble molecules involved in inflammation, endothelial damage, or hemostasis are recognized as potential cardiovascular risk markers. Studies to assess the role of these markers in the atherosclerotic process by evaluating their relationship to carotid intima-media thickness (C-IMT) tend to provide contrasting results.

PURPOSE

To perform a review of studies addressing the association between C-IMT and soluble markers and to investigate whether the observed inconsistencies could be explained by the characteristics of the patients included in different studies, for example prevalence of atherosclerotic disease (atherosclerotic burden), gender, age, or occurrence of specific vascular risk factors (VRFs).

DATA SOURCES

PubMed and Embase (January 1990 to March 2006).

STUDY SELECTION

Articles in English reporting original cross-sectional studies.

DATA EXTRACTION

Two authors independently extracted data on study design, population, sample size, ultrasonic methodology, and statistical approach.

DATA SYNTHESIS

Despite the marked heterogeneity of results presented in the literature, meta-analysis established that studies showing positive associations between C-IMT and plasma levels of C-reactive protein (CRP) or fibrinogen are in the majority. Funnel plot analyses suggested the absence of an important publication bias. Data on the relationships between C-IMT and other soluble markers are by contrast scanty, contradictory, or unconfirmed by multivariate (as opposed to univariate) analyses, and the freedom from publication bias here cannot be vouched for. The degree of atherosclerotic burden in the population studied does not account for the heterogeneity of findings reported. Gender, noninsulin-dependent diabetes mellitus (NIDDM) and hypercholesterolemia influence the association between C-IMT and CRP. Blood pressure and hypercholesterolemia influence the association between C-IMT and fibrinogen. For all the other soluble markers considered, the number of groups was too small for this kind of statistical considerations.

LIMITATIONS

Heterogeneity in ultrasound methodologies and in statistical approach limited comparability between studies. For most soluble markers, publication bias of positive results cannot be excluded.

CONCLUSIONS

Only CRP and fibrinogen seem to be unequivocally related to C-IMT. For all the other soluble markers considered, no clear-cut conclusions can be drawn.

The risk of metabolic syndrome according to the high-sensitivity C-reactive protein in apparently healthy Koreans

BACKGROUND

Recently, considerable interest has been focused on the positive relationship between inflammation and the metabolic syndrome (MS). Therefore, we investigated whether the baseline plasma levels of the high-sensitivity C-reactive protein could be associated with future risk for MS in apparently healthy Koreans.

METHODS

A total of 1132 subjects (767 men, 365 women with a mean age of 49 years), who underwent health examination at this hospital in both 2002 and 2005 were enrolled. The criteria for metabolic syndrome followed that of NCEP-ATP III guideline except waist circumference. Instead, BMI (>/=25 kg/m(2)) was used for the measurement for obesity.

RESULTS AND CONCLUSIONS

The relative risks of future MS in the highest quartile of high-sensitivity C-reactive protein at baseline were 2.4 (95% confidence interval [CI], 1.3-4.2) as compared to the subjects in the lowest quartile. Positive associations persisted after adjustment for age, sex and smoking; multivariate relative risks for the highest vs lowest quartiles were 2.3 (95% CI, 1.3-4.1; P for trend=0.005). This retrospective study suggests that elevated levels of high-sensitivity C-reactive protein could be associated with incident MS.

Association of C-reactive protein with early-stage carotid atherosclerosis in Japanese patients with early-state type 2 diabetes mellitus

The aim of this study was to assess the association between high sensitivity-C-reactive protein (hs-CRP), a sensitive marker of inflammation, and early-stage carotid atherosclerosis, in patients with early-state type 2 diabetes mellitus. The study subjects were 75 patients with type 2 diabetes mellitus without obvious diabetic vascular complications, who were not on any medication, and whose HbA(1c) level was less than 6.5%. We evaluated the mean intima-media thickness (IMT) of the common carotid artery (CCA) by ultrasound B-mode imaging. Then, we investigated various factors associated with CCA-IMT including hs-CRP. Serum hs-CRP levels correlated well with factors strongly associated with insulin resistance such as homeostasis model assessment of insulin resistance (HOMA-IR), fasting insulin level, and body mass index. Serum hs-CRP also correlated with mean CCA-IMT and serum levels of soluble intercellular adhesion molecule-1. Multivariate regression analysis using mean CCA-IMT as the dependent variable identified only age, hs-CRP, and diastolic blood pressure as independent determinants of mean CCA-IMT. While hs-CRP associates with insulin resistance and subclinical atherosclerosis in ealy-state type 2 diabetes, our data suggest that hs-CRP is a useful marker of subclinical atherosclerosis in early-state type 2 diabetes mellitus independent of factors that directly reflect insulin resistance.

Association Between Components of the Metabolic Syndrome and Serum Levels of C-Reactive Protein in Japanese Workingmen

Middle-aged workingmen (N=984) with no present medical treatment were enrolled to determine whether there is an association between the metabolic syndrome (MetS) and serum levels of C-reactive protein. MetS was defined as follows: waist circumference > or = 85 cm as a necessary criterion; in addition, two or more of the following criteria were required: serum triglycerides > or = 150 mg/dL and/or highdensity lipoprotein cholesterol <40 mg/dL; systolic blood pressure > or = 130 mm Hg and/or diastolic blood pressure > or = 85 mm Hg; fasting blood glucose > or = 110 mg/dL. Three groups were identified by the components of MetS: a reference group of subjects with a waist circumference <85 cm; group A, with a waist circumference > or = 85 cm with no or one additional MetS criterion; and group B, subjects satisfying the criteria for a diagnosis of MetS. Logistic regression analysis revealed that the components of MetS contributed significantly to serum levels of C-reactive protein. The odds ratios were 2.5 (group A) and 4.0 (group B), when 3 mg/L was adopted as the cutoff value of C-reactive protein.

Differential expression of proteins in kidney, eye, aorta, and serum of diabetic and non-diabetic rats

Diabetes mellitus (DM) is a chronic progressive disease that often results in microvascular and macrovascular complications, yet its pathogenesis is not clear. Automated proteomic technology, coupled with powerful bioinformatics and statistical tools, can provide new insights into the molecular alterations implicated in DM. Following our previous findings of redox changes in the eye and aorta of diabetic rats, as well as the activities of different antioxidant enzymes during the development of DM, this study is further launched to find potential biomarkers by comparing the serum and tissue samples of 26 diabetic rats (8 weeks after streptozotocin [STZ] administration) with 29 normal controls using surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) technology. Eight potential biomarkers were found in the serum, one potential biomarker was found in the kidney and eye, respectively, whereas three potential biomarkers were discovered in the aorta. One of the serum biomarker candidates was found to match the C-reactive protein (CRP) in the Swiss-Prot knowledgebase. Further validation has been conducted by ELISA kit to confirm the role of CRP during the development of DM. To conclude, the increased level of CRP in diabetic serum demonstrated in this study indicates that the development of DM is associated with inflammation. This is also the first report demonstrating that some potential lysate biomarkers in the kidney, eye, and aorta may be involved in the development of diabetes and its complications. Further identification and evaluation of these potential biomarkers will help unravel the underlying mechanisms of the disease.