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

Efficacy of L-cysteine in increasing circulatory hydrogen sulfide, nitrite, and 25(OH)VD levels in ZDF rats and in vitro treatment of H2S and NO2 in upregulating VD hydroxylase genes in monocytes

Dairy products, such as whey proteins, have been effectively utilized to enhance the effectiveness of vitamin D fortification and optimize circulating 25(OH)VD levels. Whey protein is rich in L-cysteine (LC) which is the precursor of hydrogen sulfide (H2S), enhances glutathione (GSH) biosynthesis, and promotes positive nitrogen balance. Zucker diabetic rats (ZDF) were used as a model in this study, to examine the hypothesis that LC supplementation enhances blood levels of H2S and nitrite (NO2) while reducing inflammation biomarkers. Rats were gavaged daily (orally) with either saline placebo or L-cysteine along with a high-calorie diet starting at 6 weeks of age. Fasting blood levels showed LC supplementation significantly increased circulatory levels of H2S and NO2 compared with placebo rats. LC supplementation increased plasma concentration of 25(OH)VD and vitamin C and lowered leptin and body weight gain in ZDF rats. Furthermore, to assess the impact of H2S and NO2 in raising 25(OH)VD levels, the in vitro effect of H2S/NO2 on vitamin D metabolism genes was examined using THP-1 monocytes. The exogenous H2S and NO2 treatment upregulated the relative expression of CYP2R1 and CYP27B1 genes in cultured monocytes. This study suggests a potential mechanism for the observed increase in circulating 25(OH)VD levels following L-cysteine supplementation.

Association between proinflammatory cytokines and arterial stiffness in type 1 diabetic adolescents

OBJECTIVES

Type 1 diabetes mellitus is considered a state of chronic low-grade inflammation and activation of the innate immune system, which is regulated by several proinflammatory cytokines and other acute-phase reactants. Arterial stiffness, a dynamic property of the vessels evaluated by the determination of pulse wave velocity (PWV), is increased in diabetic patients and is associated with microvascular and macrovascular complications of diabetes and higher cardiovascular risk. In the present study, we aimed to compare the proinflammatory state and arterial stiffness in diabetic and non-diabetic adolescents, and to characterize the association between these two parameters.

METHODS

Twenty-three type 1 diabetic patients, aged 12-16 years, followed at a tertiary center, and 23 adolescents nonoverweighted healthy controls, from a Portuguese birth-cohort, were included in the present analysis. Anthropometry, blood pressure, glycemic control data, and lipid parameters were collected. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity. Proinflammatory cytokines' concentrations (TNF-α, IL-1β, IL-6, IL-10, IFN-γ, and GM-CSF) were quantified by multiplex immunoassays using a Luminex 200 analyzer.

RESULTS

There were no statistically significant differences between the proinflammatory cytokines' concentrations in the two groups. PWV [6.63 (6.23-7.07) vs. 6.07 (5.15-6.65) m/s, p=0.015] was significantly higher in the diabetic group. PWV was negatively correlated with GM-CSF (ρ=-0.437, p=0.037) in the diabetic group. A linear association was found between diabetes duration and PWV (with PWV increasing by 0.094 m/s (95 % confidence interval, 0.019 to 0.169) per month of disease duration). In the diabetic group, HbA1c was negatively correlated with IL-10 (ρ=-0.473, p=0.026). Negative correlations were also found between IL-10 and total, HDL, and LDL cholesterol only in the diabetic group.

CONCLUSIONS

Diabetic adolescent patients present higher PWV, when compared to their healthy counterparts, even though we could not find differences in the levels of several proinflammatory cytokines between the two groups. The negative correlation found between IL-10 and HbA1c might translate a protective counterbalance effect of this anti-inflammatory cytokine, which might also explain the negative correlations found with blood lipids. Further studies are needed to better clarify the association between arterial stiffness and the proinflammatory milieu of diabetes.

Longitudinal Trajectories of Biomarkers of Kidney Tubular Function in Type 1 Diabetes

Introduction

Tubular biomarkers may shed insight into progression of kidney tubulointerstitial pathology complementary to traditional measures of glomerular function and damage.

Methods

We examined trajectories of tubular biomarkers in the Diabetes Control and Complications Trial and the Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC Study) of type 1 diabetes (T1D). Biomarkers were measured in a subset of 220 participants across 7 time points over 26 years. Measurements included the following: kidney injury molecule 1 (KIM-1), soluble tumor necrosis factor 1 (sTNFR1) in serum or plasma, epidermal growth factor (EGF), monocyte chemoattractant protein-1 (MCP1) in timed urine, and a composite tubular secretion score. We described biomarker trajectories and examined how these were affected by intensive glucose-lowering therapy and glycemia.

Results

At baseline, participants had a mean age of 28 years, 45% were women, and 50% were assigned to intensive glucose-lowering therapy. The mean estimated glomerular filtration rate (eGFR) was 125 ml/min per 1.73 m2 and 90% of participants had a urinary albumin excretion rate (AER) <30 mg/24h. Mean changes in biomarkers over time (percent/decade) were: KIM-1: 27.3% (95% confidence interval [CI]: 21.4-33.5), sTNFR1: 16.9% (14.5-19.3), MCP1: 18.4% (8.9-28.8), EGF: -13.5% (-16.7 to -10.1), EGF-MCP1 ratio: -26.9% (-32.2 to -21.3), and tubular secretion score -0.9% (-1.8 to 0.0), versus -12.0% (CI: -12.9 to -11.1) for eGFR and 10.9% (2.5-20.1) for AER. Intensive versus conventional glucose-lowering therapy was associated with slower increase in sTNFR1 (relative difference in change: 0.94 [0.90-0.98]). Higher HbA1c was associated with faster increases in sTNFR1 (relative difference in change: 1.06 per 1% higher HbA1c [1.05-1.08]) and KIM-1 (1.09 [1.05-1.14]).

Conclusion

Among participants with T1D and normal eGFR at baseline, kidney tubular biomarkers changed significantly over long-term follow-up. Hyperglycemia was associated with larger increases in serum or plasma sTNFR1 and KIM-1, when followed-up longitudinally.

S100A9 exerts insulin-independent antidiabetic and anti-inflammatory effects

Type 1 diabetes mellitus (T1DM) is characterized by insulin deficiency leading to hyperglycemia and several metabolic defects. Insulin therapy remains the cornerstone of T1DM management, yet it increases the risk of life-threatening hypoglycemia and the development of major comorbidities. Here, we report an insulin signaling-independent pathway able to improve glycemic control in T1DM rodents. Co-treatment with recombinant S100 calcium-binding protein A9 (S100A9) enabled increased adherence to glycemic targets with half as much insulin and without causing hypoglycemia. Mechanistically, we demonstrate that the hyperglycemia-suppressing action of S100A9 is due to a Toll-like receptor 4-dependent increase in glucose uptake in specific skeletal muscles (i.e., soleus and diaphragm). In addition, we found that T1DM mice have abnormal systemic inflammation, which is resolved by S100A9 therapy alone (or in combination with low insulin), hence uncovering a potent anti-inflammatory action of S100A9 in T1DM. In summary, our findings reveal the S100A9-TLR4 skeletal muscle axis as a promising therapeutic target for improving T1DM treatment.

Evaluation of Effects of Continuous Glucose Monitoring on Physical Activity Habits and Blood Lipid Levels in Persons With Type 1 Diabetes Managed With Multiple Daily Insulin Injections: An Analysis Based on the GOLD Randomized Trial (GOLD 8)

BACKGROUND

People with type 1 diabetes generally view it easier to exercise when having continuous information of the glucose levels. We evaluated whether patients with type 1 diabetes managed with multiple daily insulin injections (MDI) exercised more after initiating continuous glucose monitoring (CGM) and whether the improved glycemic control and well-being associated with CGM translates into improved blood lipids and markers of inflammation.

METHOD

The GOLD trial was a randomized cross-over trial over 16 months where patients used either CGM or capillary self-monitoring of blood glucose (SMBG) over six months, with a four-month wash-out period between the two treatment periods. We compared grade of physical activity, blood lipids, apolipoproteins, and high-sensitivity C-reactive protein (hsCRP) levels during CGM and SMBG.

RESULTS

There were 116 patients with information of physical activity estimated by the International Physical Activity Questionnaire (IPAQ) during both CGM and SMBG. No changes were found during CGM or SMBG, IPAQ scores 3305 versus 3878 (P = .16). In 136 participants with information of blood lipid levels with no change in lipid-lowering medication during the two treatment periods, HbA1c differed by 4.2 mmol/mol (NGSP 0.39%) between SMBG and CGM treatment (P < .001). No significant changes existed in low-density lipoprotein, high-density lipoprotein, triglycerides, total cholesterol, apolipoprotein A1, apolipoprotein B1, or hsCRP, during CGM and SMBG.

CONCLUSION

Although many patients experience it easier to perform physical activity when monitoring glucose levels with CGM, it does not influence the amount of physical activity in persons with type 1 diabetes. Blood lipids, apolipoprotein, and hsCRP levels were similar during CGM and SMBG.

Disease Duration and Chronic Complications Associate With Immune Activation in Individuals With Longstanding Type 1 Diabetes

CONTEXT

Type 1 diabetes (T1D) is associated with alterations of the immune response which persist even after the autoimmunity aspect is resolved. Clinical factors that cause dysregulation, however, are not fully understood.

OBJECTIVE

To identify clinical factors that affect immune dysregulation in people with longstanding T1D.

DESIGN

In this cross-sectional study, 243 participants with longstanding T1D were recruited between February 2016 and June 2017 at the Radboudumc, the Netherlands. Blood was drawn to determine immune cell phenotype and functionality, as well as circulating inflammatory proteome. Multivariate linear regression was used to determine the association between glycated hemoglobin (HbA1c) levels, duration of diabetes, insulin need, and diabetes complications with inflammation.

RESULTS

HbA1c level is positively associated with circulating inflammatory markers (P < .05), but not with immune cell number and phenotype. Diabetes duration is associated with increased number of circulating immune cells (P < .05), inflammatory proteome (P < .05), and negatively associated with adaptive immune response against Mycobacterium tuberculosis and Rhizopus oryzae (P < .05). Diabetes nephropathy is associated with increased circulating immune cells (P < .05) and inflammatory markers (P < .05).

CONCLUSION

Disease duration and chronic complications associate with persistent alterations in the immune response of individuals with long standing T1D.

Cardiovascular disease in diabetes, beyond glucose

Despite the decades-old knowledge that diabetes mellitus is a major risk factor for cardiovascular disease, the reasons for this association are only partially understood. While this association is true for both type 1 and type 2 diabetes, different pathophysiological processes may be responsible. Lipids and other risk factors are indeed important, whereas the role of glucose is less clear. This lack of clarity stems from clinical trials that do not unambiguously show that intensive glycemic control reduces cardiovascular events. Animal models have provided mechanisms that link diabetes to increased atherosclerosis, and evidence consistent with the importance of factors beyond hyperglycemia has emerged. We review clinical, pathological, and animal studies exploring the pathogenesis of atherosclerosis in humans living with diabetes and in mouse models of diabetes. An increased effort to identify risk factors beyond glucose is now needed to prevent the increased cardiovascular disease risk associated with diabetes.

Current Status and Potential Therapeutic Strategies for Using Non-coding RNA to Treat Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DMCM) is the leading cause of mortality and morbidity among diabetic patients. DMCM is characterized by an increase in oxidative stress with systemic inflammation that leads to cardiac fibrosis, ultimately causing diastolic and systolic dysfunction. Even though DMCM pathophysiology is well studied, the approach to limit this condition is not met with success. This highlights the need for more knowledge of underlying mechanisms and innovative therapies. In this regard, emerging evidence suggests a potential role of non-coding RNAs (ncRNAs), including micro-RNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) as novel diagnostics, mechanisms, and therapeutics in the context of DMCM. However, our understanding of ncRNAs’ role in diabetic heart disease is still in its infancy. This review provides a comprehensive update on pre-clinical and clinical studies that might develop therapeutic strategies to limit/prevent DMCM.

Soluble Klotho Is Decreased in Children With Type 1 Diabetes and Correlated With Metabolic Control

Klotho concentration may be considered as a prognostic factor in the development of chronic complications of diabetes. Moreover, decrease in sKlotho concentration may contribute to beta cell apoptosis and type 1 diabetes development. The aim of this study was to evaluate if sKlotho protein concentration in children with type 1 diabetes (T1D) and its correlation with classical risk factors of chronic complications of diabetes: dysglycemia and endothelial dysfunction.

MATERIAL AND METHODS

In a cross-section single center study the levels of soluble Klotho protein in 80 T1D (37 boys) and 34 healthy children (controls, 15 boys). Micro- and macroangiopathy were excluded and renal function was normal in all participants. Serum sKlotho, sICAM-1, sVCAM-1 and E-selectin levels were measured.

RESULTS

The concentration of sKlotho was lower in T1D than in the controls (2041.9 ± 1017.6 pg/mL vs. 2790.3 ± 1423.9 pg/mL, p=0.0113). sICAM-1, sVCAM-1 and E-selectin concentrations were comparable in patients and controls. In T1D, sKlotho was not correlated with the duration of diabetes. Klotho and E-selectin were correlated with HbA1c (r=-0.31, P=0.0066 and r=0.25, P=0.0351, respectively), but not with AVBG and blood glucose SD. Correlations of sKlotho with total cholesterol (r=0.31, P=0.0129), HDL-cholesterol (r=0.43, P=0.0011) and LDL-cholesterol (r=0.28, P=0.0412), but not with triglycerides, were found. Likewise, Klotho was not correlated with sICAM-1, sVCAM-1, and E-selectin concentrations.

CONCLUSIONS

This study reports the significantly lower level of s-Klotho in children with type 1 diabetes, correlated with HbA1c and HDL cholesterol, but not with the adhesion molecules concentrations nor the duration of the disease. Negative correlation between the levels of HbA1c and soluble Klotho may suggest its possible involvement in the development of chronic diabetes complications.

Circulating Inflammatory Markers Are Inversely Associated with Heart Rate Variability Measures in Type 1 Diabetes

Introduction

A neuroimmune communication exists, and compelling evidence suggests that diabetic neuropathy and systemic inflammation are linked. Our aims were (1) to investigate biomarkers of the ongoing inflammation processes including cytokines, adhesion molecules, and chemokines and (2) to associate the findings with cardiovascular autonomic neuropathy in type 1 diabetes by measuring heart rate variability and cardiac vagal tone.

Materials and Methods

We included 104 adults with type 1 diabetes. Heart rate variability, time domain, and frequency domains were calculated from a 24-hour Holter electrocardiogram, while cardiac vagal tone was determined from a 5-minute electrocardiogram. Cytokines (interleukin- (IL-) 1α, IL-4, IL-12p70, IL-13, IL-17, and tumor necrosis factor- (TNF-) α), adhesion molecules (E-selectin, P-selectin, and intercellular adhesion molecule- (ICAM-) 1), and chemokines (chemokine (C-C motif) ligand (CCL)2, CCL3, CCL4, and C-X-C motif chemokine (CXCL)10) were assessed using a Luminex multiplexing technology. Associations between concentrations of inflammatory biomarkers and continuous variables of heart rate variability and cardiac vagal tone were estimated using multivariable linear regression adjusting for age, sex, disease duration, and smoking.

Results

Participants with the presence of cardiovascular autonomic neuropathy had higher systemic levels of IL-1α, IL-4, CCL2, and E-selectin than those without cardiovascular autonomic neuropathy. IL-1α, IL-4, IL-12, TNF-α, and E-selectin were inversely associated with both sympathetic and parasympathetic heart rate variability measures (p > 0.01). Discussion. Our results show that several pro- and anti-inflammatory factors, believed to be involved in the progression of diabetic polyneuropathy, are associated with cardiovascular autonomic neuropathy, suggesting that these factors may also contribute to the pathogenesis of cardiovascular autonomic neuropathy. Our findings emphasize the importance of the neuroimmune regulatory system in the pathogenesis of neuropathy in type 1 diabetes.

Children with type 1 diabetes have elevated high-sensitivity C-reactive protein compared with a control group

INTRODUCTION

Our objective was to compare high-sensitivity C-reactive protein (hsCRP) levels in children with type 1 diabetes, healthy controls, and children with obesity. Additionally, we aimed to analyze the association between hsCRP levels and glycemic control measured by glycohemoglobin A (HbA1c) and anthropometric and biochemical variables.

RESEARCH DESIGN AND METHODS

We conducted a non-randomized descriptive study of children with type 1 diabetes matched for sex and age with a control group and group with obesity. We recorded anthropometric parameters and studied variables related to diabetes, blood pressure, lipid profile, and HbA1c. hsCRP was measured by ELISA.

RESULTS

We included 49 children with type 1 diabetes, 46 controls, and 40 children with obesity. hsCRP levels were significantly higher in the group with type 1 diabetes compared with controls and nearly significantly lower than in the group comprising children with obesity. We found no correlation between hsCRP and HbA1c and characteristics of type 1 diabetes with the exception of albumin to creatinine ratio. Statistically significant association was found between hsCRP and body mass index (BMI) and waist circumference Z-score.

CONCLUSIONS

The higher hsCRP levels observed in children with type 1 diabetes compared with a control group with a similar BMI suggest a basal inflammatory state that could increase cardiovascular risk. The main factors related to hsCRP are BMI and waist circumference, so obesity prevention should be a priority when performing follow-up in children with type 1 diabetes.

Effects of Chromium Picolinate Supplementation on Cardiometabolic Biomarkers in Patients with Type 2 Diabetes Mellitus: a Randomized Clinical Trial

Type 2 diabetes mellitus (T2DM) is a serious public health problem accompanies with several complications. This study was conducted to evaluate the effects of chromium picolinate (CrPic) supplementation on the glycemic status and lipid profile in patients with T2DM. The patients with T2DM (n = 52) were randomly allocated into 2 groups. One group received 400 µg CrPic per day and the other group took placebo; the intervention duration was 8 weeks. Anthropometric indices and metabolic factors were measured at the beginning, and at end of the study. The patients were recommended not to change their normal diet, life style and medication. No significant changes were observed for weight, body mass index, and fasting blood glucose (FBG) in both groups; while intra-groups changes in homeostatic model assessment for insulin resistance (HOMA-IR) value was significant (p < 0.05). Results of analysis of covariance showed that there were significance differences between groups in total cholesterol, low density lipoprotein cholesterol and HOMA-IR at the end of the intervention adjusting for baseline levels (p = 0.035, 0.030 and < 0.001, respectively). In this study, oral supplementation with 400 µg CrPic for eight weeks did not alter FBG concentration as well as anthropometric parameters in individuals with T2DM. However, the modest beneficial effects of chromium supplementation on insulin resistance as indicated by HOMA-IR and lipid profile were found.

Histological effects of pharmacologically active human bile acid nano/micro-particles in Type-1 diabetes

Aim: Gliclazide (G) is a drug prescribed for Type 2 diabetics, although recent studies suggest it has desirable effects in both types of diabetes, Type 1 diabetes and Type 2 diabetes. G has an inconsistent absorption due to poor formulation and bile acids (BAs) have shown significant promise in drug formulation optimization. Hence, the study aimed to examine G effects on histopathological, anti-inflammatory and antidiabetic effects when encapsulated with BAs. Materials & methods: Rats were randomized into eight groups, of which seven were made Type 1 diabetes and treated with various BA-based treatments. Tissue histopathology, inflammation and the bile acid profile were analyzed. Results & conclusion: G capsules showed no histological but the most anti-inflammatory effects, which suggest significant beneficial effects in diabetes treatment.

The roles of bile acids and applications of microencapsulation technology in treating Type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the loss of glycemic control. Recent studies have shown significant inflammation and disturbed bile acid homeostasis, associated with T1DM. Bile acids are endogenously produced as a result of cholesterol catabolism in the liver and solely metabolized by gut microflora. This review investigates their potential oral delivery in T1DM using targeted delivery and encapsulation technologies. A sensitive and selective search was carried out using different search engines and databases. Keywords used included diabetes mellitus, bile acids and inflammation. To conclude, bile acids have a significant impact on diabetes symptoms and, when microencapsulated, may be used as an adjunct therapy to supplement T1DM treatment.

Biomarkers of inflammation and endothelial dysfunction as predictors of pulse pressure and incident hypertension in type 1 diabetes: a 20 year life-course study in an inception cohort

AIMS/HYPOTHESIS

Vascular inflammation and endothelial dysfunction are thought to contribute to arterial stiffening and hypertension. This study aims to test this hypothesis with longitudinal data in the context of type 1 diabetes.

METHODS

We investigated, in an inception cohort of 277 individuals with type 1 diabetes, the course, tracking and temporal inter-relationships of BP, specifically pulse pressure (a marker of arterial stiffening) and hypertension, and the following biomarkers of systemic and vascular inflammation/endothelial dysfunction: C-reactive protein (CRP), soluble intracellular adhesion molecule-1 (sICAM-1), soluble vascular cellular adhesion molecule-1 (sVCAM-1) and soluble E-selectin (sE-selectin). These biomarkers and other risk factors were measured at baseline and repeatedly up to 20 years after the onset of type 1 diabetes. Data were analysed with generalised estimating equations including adjustments for age, sex, smoking status, BMI, HbA_1c, serum creatinine, total cholesterol, urinary AER, insulin treatment dose and mean arterial pressure.

RESULTS

Increases were noted in all biomarkers except sE-selectin, which decreased over time. Levels differed from baseline at 2-4 years and preceded the increase in pulse pressure, which occurred at 8-10 years after the onset of type 1 diabetes. Higher levels of sICAM-1 and sVCAM-1, but not CRP or sE-selectin, at baseline and throughout the 20 year follow-up, were significantly associated with higher (changes in) pulse pressure at subsequent time points. Higher levels of sVCAM-1 at baseline and during follow-up were also significantly associated with the prevalence (OR 3.60 [95% CI 1.36, 9.53] and OR 2.28 [1.03, 5.25], respectively) and incidence (OR 2.89 [1.08, 7.75] and OR 3.06 [1.01, 9.26], respectively) of hypertension. We also investigated the longitudinal associations between BP or hypertension as determinants of subsequent (changes in) levels of CRP, sICAM-1, sVCAM-1 and sE-selectin, but did not find evidence to support a reverse causality hypothesis.

CONCLUSIONS/INTERPRETATION

These findings support the involvement of vascular endothelial dysfunction and inflammation in the development of premature arterial stiffening and hypertension in type 1 diabetes.

Influence of Biotechnological Processes, Speed of Formulation Flow and Cellular Concurrent Stream-Integration on Insulin Production from β-cells as a Result of Co-Encapsulation with a Highly Lipophilic Bile Acid

Introduction

We have shown that incorporation of the hydrophilic bile acid, ursodeoxycholic acid, into β-cell microcapsules exerted positive effects on microcapsules' morphology and size, but these effects were excipient and method dependent. Cell viability remained low which suggests low octane-water solubility and formation of highly hydrophilic dispersion, which resulted in low lipophilicity dispersion and compromised cellular permeation of the incorporated bile acid. Thus, this study aimed at investigating various microencapsulating methodologies using highly lipophilic bile acid (LPBA), in order to optimise viability and functions of microencapsulated β-cells.

Methods

Four different types of microcapsules were produced with (test) and without (control) LPBA, totalling eight different microcapsules. Microencapsulating methodologies were screened for best microcapsule-cell functions and microencapsulating processes were examined in terms of frequency, formulation flow, total bath-gelation time and cellular concurrent stream-integration rate, cell-viability, insulin production and inflammatory profile.

Results

Optimum biotechnological processes include formation frequency (Hz) of 2350, formulation flow (ml/min) of 1.2, total gelation time (min) of 18 and cellular concurrent stream-integration rate (ml/min) of 0.7. In all formulations, LPBA consistently improved cell viability, insulin production, mitochondrial activities and ameliorated inflammation.

Conclusion

The deployed biotechnological processes and LPBA optimised formation and functions of β-cell microcapsules, which suggests potential applications in diabetes mellitus via the creation of more stable β-cell microcapsules capable of delivering adequate levels of insulin to control glycaemia and potentially curing diabetes.

Impact of chromium dinicocysteinate supplementation on inflammation, oxidative stress, and insulin resistance in type 2 diabetic subjects: an exploratory analysis of a randomized, double-blind, placebo-controlled study

Background

Chromium dinicocysteinate (CDNC) is a unique chromium complex consisting of chromium, niacin, and L-cysteine. Previous preclinical and clinical studies support the safety and efficacy of CDNC in modulating oxidative stress, vascular inflammation, and glycemia in type 2 diabetes.

Objective

Herein, we report the results of several exploratory analyses conducted on type 2 diabetic subjects who previously participated in a 3-month randomized, double-blind, placebo-controlled trial and were treated with only metformin as standard diabetic care in addition to receiving the test supplementations.

Design

Results from 43 metformin users, who were randomly assigned to receive either placebo (P, n=13), chromium picolinate (CP, 400 µg elemental Cr³⁺/day, n=12), or CDNC (400 µg elemental Cr³⁺/day, n=18), were analyzed for blood markers of vascular inflammation, insulin resistance, and oxidative stress at baseline and at 3 months of supplementation.

Results

A statistically significant decrease in insulin resistance in the CDNC-supplemented cohort compared to placebo (p=0.01) was observed at 3 months. The CDNC group also demonstrated a significant reduction in insulin levels (p=0.03), protein carbonyl (p=0.02), and in TNF-α (p=0.03) compared to the placebo group. The CP group only showed a significant reduction in protein carbonyl levels (p=0.03) versus placebo.

Conclusions

When controlling for diabetes medication, CDNC supplementation showed beneficial effects on blood markers of vascular inflammation, insulin resistance, and oxidative stress compared to placebo. The findings suggest that CDNC supplementation has potential as an adjunct therapy for individuals with type 2 diabetes.

Review: The metabolic syndrome as an endocrine disease: is there an effective pharmacotherapeutic strategy optimally targeting the pathogenesis?

The metabolic syndrome (MetS) represents a combination of cardiovascular risk determinants such as obesity, insulin resistance and lipid abnormalities such as hypertriglyceridemia, increased free fatty acids, low high-density-cholesterol and hypertension. As a multiple component condition it imparts a doubling of relative risk for atherosclerotic cardiovascular disease (ASCVD). It is currently controversial which component of the syndrome carries what weight. There is even a considerable debate whether the risk for ASCVD is greater in patients diagnosed with MetS than that by the individual risk factors. At present, no unifying pathogenetic mechanism can explain the metabolic syndrome and there is no unique treatment for it. This review summarizes and critically reviews the currently available clinical and scientific evidence for the concept that the MetS is causally an endocrine disease and discusses pharmacotherapeutic strategies targeting the pathogenesis rather than single symptoms of the cluster.

Paradox of using intensive lowering of blood glucose in diabetics and strategies to overcome it and decrease cardiovascular risks

Hyperglycemia significantly increases the risk of cardiovascular disease (CVD) in diabetics. However, it has been shown by a series of large scale international studies that intensive lowering of blood glucose levels not only has very limited benefits against cardiovascular problems in patients, but may even be harmful to patients at a high risk for CVD and/or poor long-term control of blood glucose levels. Therefore, Western medicine is faced with a paradox. One way to solve this may be administration of Chinese herbal medicines that not only regulate blood glucose, blood fat levels and blood pressure, but also act on multiple targets. These medicines can eliminate cytotoxicity of high glucose through anti-inflammatory and anti-oxidant methods, regulation of cytokines and multiple signaling molecules, and maintenance of cell vitality and the cell cycle, etc. This allows hyperglycemic conditions to exist in a healthy manner, which is called "harmless hyperglycemia" Furthermore, these cardiovascular benefits go beyond lowering blood glucose levels. The mechanisms of action not only avoid cardiovascular injury caused by intensive lowering of blood glucose levels, but also decrease the cardiovascular dangers posed by hyperglycemia.

The Role of Markers of Low-Grade Inflammation for the Early Time Course of Glycemic Control, Glucose Disappearance Rate, and β-Cell Function in Recently Diagnosed Type 1 and Type 2 Diabetes

OBJECTIVE

Inflammatory processes are involved in the progression of insulin resistance and β-cell dysfunction in individuals with prediabetes and contribute to the development of diabetes. We hypothesized that higher levels of biomarkers of low-grade inflammation are associated with the early progression of recently diagnosed diabetes.

RESEARCH DESIGN AND METHODS

Within the prospective German Diabetes Study, patients with recently diagnosed type 1 (n = 42) and type 2 (n = 94) diabetes underwent detailed metabolic characterization within the first year after diagnosis and 2 years thereafter. Associations between changes in markers of low-grade inflammation with changes in glycemic control, β-cell function, and glucose disappearance rate were assessed using multivariable linear regression analysis. Associations were adjusted for age, sex, BMI, smoking status, and 2-year changes in BMI, smoking status, and glucose-lowering medication.

RESULTS

Patients with type 1 and type 2 diabetes exhibited good glucometabolic control at baseline (mean HbA1c 7.08 ± 1.58% [54 ± 17 mmol/mol] and 6.43 ± 0.98% [47 ± 11 mmol/mol], respectively) and 2 years thereafter (mean HbA1c 7.03 ± 1.20% [53 ± 13 mmol/mol] and 6.62 ± 1.14% [49 ± 13], respectively). Two-year increases of high-sensitivity C-reactive protein, soluble E-selectin (sE-selectin), and soluble intercellular adhesion molecule-1 in type 2 diabetes and of IL-18 in type 1 diabetes were associated with 2-year increases of HbA1c. Additionally, 2-year increases of sE-selectin were associated with 2-year decreases of prehepatic β-cell function in type 2 diabetes (all P < 0.05).

CONCLUSIONS

These data indicate that with the clinical onset of diabetes, low-grade inflammation relates to worsening of glycemia and that endothelial activation may contribute to decreasing β-cell function.

Effect of Rosiglitazone and Insulin Combination Therapy on Inflammation Parameters and Adipocytokine Levels in Patients with Type 1 DM

AIM

To investigate the efficacy of combined therapy of insulin and rosiglitazone on metabolic and inflammatory parameters, insulin sensitivity, and adipocytokine levels in patients with type 1 diabetes mellitus (type 1 DM).

MATERIAL AND METHODS

A total of 61 adults with type 1 DM were randomly and prospectively assigned in open-label fashion to take insulin and rosiglitazone 4 mg/day (n = 30) or insulin alone (n = 31) for a period of 18 weeks while undergoing insulin therapy without acute metabolic complications.

RESULTS

Combination therapy did not significantly improve metabolic and inflammatory parameters, insulin sensitivity, and adiponectin levels. While leptin and resistin levels decreased in both groups (group 1: resistin 6.96 ± 3.06 to 4.99 ± 2.64, P = 0.006; leptin 25.8 ± 17.6 to 20.1 ± 12.55, P = 0.006; group 2: resistin 7.16 ± 2.30 to 5.57 ± 2.48, P = 0.031; leptin 16.72 ± 16.1 to 14.0 ± 13.4, P = 0.007) Hgb and fibrinogen levels decreased only in group 1 (Hgb 13.72 ± 1.98 to 13.16 ± 1.98, P = 0.015, and fibrinogen 4.00 ± 1.08 to 3.46 ± 0.90, P = 0.002). Patients in both groups showed weight gain and the incidence of hypoglycemia was not lower.

DISCUSSION

The diverse favorable effects of TZDs were not fully experienced in patients with type 1 DM. These results are suggesting that insulin sensitizing and anti-inflammatory characteristics of TZDs were likely to be more pronounced in patients who were not totally devoid of endogenous insulin secretion.

Intensive glucose control versus conventional glucose control for type 1 diabetes mellitus

BACKGROUND

Clinical guidelines differ regarding their recommended blood glucose targets for patients with type 1 diabetes and recent studies on patients with type 2 diabetes suggest that aiming at very low targets can increase the risk of mortality.

OBJECTIVES

To assess the effects of intensive versus conventional glycaemic targets in patients with type 1 diabetes in terms of long-term complications and determine whether very low, near normoglycaemic values are of additional benefit.

SEARCH METHODS

A systematic literature search was performed in the databases The Cochrane Library, MEDLINE and EMBASE. The date of the last search was December 2012 for all databases.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that had defined different glycaemic targets in the treatment arms, studied patients with type 1 diabetes, and had a follow-up duration of at least one year.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, assessed studies for risk of bias, with differences resolved by consensus. Overall study quality was evaluated by the 'Grading of Recommendations Assessment, Development, and Evaluation' (GRADE) system. Random-effects models were used for the main analyses and the results are presented as risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes.

MAIN RESULTS

We identified 12 trials that fulfilled the inclusion criteria, including a total of 2230 patients. The patient populations varied widely across studies with one study only including children, one study only including patients after a kidney transplant, one study with newly diagnosed adult patients, and several studies where patients had retinopathy or microalbuminuria at baseline. The mean follow-up duration across studies varied between one and 6.5 years. The majority of the studies were carried out in the 1980s and all trials took place in Europe or North America. Due to the nature of the intervention, none of the studies could be carried out in a blinded fashion so that the risk of performance bias, especially for subjective outcomes such as hypoglycaemia, was present in all of the studies. Fifty per cent of the studies were judged to have a high risk of bias in at least one other category.Under intensive glucose control, the risk of developing microvascular complications was reduced compared to conventional treatment for a) retinopathy: 23/371 (6.2%) versus 92/397 (23.2%); RR 0.27 (95% CI 0.18 to 0.42); P < 0.00001; 768 participants; 2 trials; high quality evidence; b) nephropathy: 119/732 (16.3%) versus 211/743 (28.4%); RR 0.56 (95% CI 0.46 to 0.68); P < 0.00001; 1475 participants; 3 trials; moderate quality evidence; c) neuropathy: 29/586 (4.9%) versus 86/617 (13.9%); RR 0.35 (95% CI 0.23 to 0.53); P < 0.00001; 1203 participants; 3 trials; high quality evidence. Regarding the progression of these complications after manifestation, the effect was weaker (retinopathy) or possibly not existent (nephropathy: RR 0.79 (95% CI 0.37 to 1.70); P = 0.55; 179 participants with microalbuminuria; 3 trials; very low quality evidence); no adequate data were available regarding the progression of neuropathy. For retinopathy, intensive glucose control reduced the risk of progression in studies with a follow-up duration of at least two years (85/366 (23.2%) versus 154/398 (38.7%); RR 0.61 (95% CI 0.49 to 0.76); P < 0.0001; 764 participants; 2 trials; moderate quality evidence), while we found evidence for an initial worsening of retinopathy after only one year of intensive glucose control (17/49 (34.7%) versus 7/47 (14.9%); RR 2.32 (95% CI 1.16 to 4.63); P = 0.02; 96 participants; 2 trials; low quality evidence).Major macrovascular outcomes (stroke and myocardial infarction) occurred very rarely, and no firm evidence could be established regarding these outcome measures (low quality evidence).We found that intensive glucose control increased the risk for severe hypoglycaemia, however the results were heterogeneous and only the 'Diabetes Complications Clinical Trial' (DCCT) showed a clear increase in severe hypoglycaemic episodes under intensive treatment. A subgroup analysis according to the baseline haemoglobin A1c (HbA1c) of participants in the trials (low quality evidence) suggests that the risk of hypoglycaemia is possibly only increased for patients who started with relatively low HbA1c values (< 9.0%). Several of the included studies also showed a greater weight gain under intensive glucose control, and the risk of ketoacidosis was only increased in studies using insulin pumps in the intensive treatment group (very low quality evidence).Overall, all-cause mortality was very low in all studies (moderate quality evidence) except in one study investigating renal allograft as treatment for end-stage diabetic nephropathy. Health-related quality of life was only reported in the DCCT trial, showing no statistically significant differences between the intervention and comparator groups (moderate quality evidence). In addition, only the DCCT published data on costs, indicating that intensive glucose therapy control was highly cost-effective considering the reduction of potential diabetes complications (moderate quality evidence).

AUTHORS' CONCLUSIONS

Tight blood sugar control reduces the risk of developing microvascular diabetes complications. The evidence of benefit is mainly from studies in younger patients at early stages of the disease. Benefits need to be weighed against risks including severe hypoglycaemia, and patient training is an important aspect in practice. The effects of tight blood sugar control seem to become weaker once complications have been manifested. However, further research is needed on this issue. Furthermore, there is a lack of evidence from RCTs on the effects of tight blood sugar control in older patient populations or patients with macrovascular disease. There is no firm evidence for specific blood glucose targets and treatment goals need to be individualised taking into account age, disease progression, macrovascular risk, as well as the patient's lifestyle and disease management capabilities.

Development of diabetic nephropathy in nude mice

BACKGROUND

Immune dysfunction is very common in diabetes mellitus (DM). However, there is no evidence whether such immune dysfunction can influence the development of DM, especially the development of diabetic nephropathy (DN).

AIM

To investigate the influence of absence of T cells on DN.

MATERIALS AND METHODS

Balb/c nude mice and Balb/c wild-type nude (WT) mice were injected with streptozotocin (STZ). Serum tumor necrosis factor α (TNF-α), blood glucose, body weight, urine albumin/creatinine ratio and rate of kidney weight to body weight (KW/BW) were measured.

RESULTS

After modeling, there was no difference of blood glucose level between nude mice and WT mice except at week 2 (28.3 ± 4.9 mmol/l vs 23.1 ± 3.9 mmol/l, p<0.01). At week 4, the serum TNF- α level of nude mice got to 175.08 ± 46.03 pg/ml (p<0.05, compared with baseline level 80.19 ± 8.46 pg/ml), whereas the TNF- α levels of WT mice was stable. At week 4, the body weight of nude mice was lower than that of WT mice (14.7 ± 3.15 g vs 17.97 ± 2.85 g, p<0.05); the urine albumin/creatinine ratio (Alb/Cr) of nude mice was higher than that of WT mice (50.96 ± 5.57 mg/mmol vs 41.09 ± 5.79 mg/mmol, p<0.05); the kidney weight to body weight of nude mice was higher than that of WT mice (0.01352 ± 0.00163 vs 0.01173 ± 0.00131, p<0.05). Correlation analysis showed urine Alb/Cr positively correlated with serum TNF-α level at week 4 (r = 0.588, p<0.01). At week 4, the increase of type IV collagen in the glomeruli was more prominent in diabetic nude mice than in diabetic WT mice (p<0.05).

CONCLUSIONS

Absence of T cells in DM might influence the development of DN.

Prospective study of inflammatory biomarkers and risk of diabetic retinopathy in the diabetes control and complications trial

IMPORTANCE

This study demonstrates that increasing quintiles of baseline high-sensitivity C-reactive protein (hsCRP) level may be associated with higher risk of incident clinically significant macular edema, the leading cause of vision loss in working-aged individuals in North America.

OBJECTIVE

To determine whether baseline levels of hsCRP and intercellular adhesion molecule 1 (ICAM-1) predict development and progression of diabetic retinopathy (DR), clinically significant macular edema (CSME), retinal hard exudates, and proliferative DR in the Diabetes Control and Complications Trial (DCCT) cohort.

DESIGN

The DCCT was a large multicenter randomized controlled clinical trial.

SETTING

Twenty-nine medical centers in the United States and Canada.

PARTICIPANTS

The DCCT population consisted of 1441 subjects with type 1 diabetes mellitus aged 13 to 39 years at study entry.

INTERVENTION

We measured levels of hsCRP, ICAM-1, vascular cell adhesion molecule 1, and tumor necrosis factor α receptor 1 in stored baseline blood samples.

MAIN OUTCOME MEASURES

We assessed the association of levels of hsCRP, ICAM-1, vascular cell adhesion molecule 1, and tumor necrosis factor α receptor 1 with incident DR end points ascertained from grading of standardized 7-field stereoscopic retinal color photographs taken at baseline and every 6 months during follow-up.

RESULTS

After adjustment for randomized treatment assignment and other factors, we observed a statistically significant association between hsCRP and risk of CSME, with a relative risk (RR) for the top vs bottom quintile of 1.83 (95% CI, 0.94-3.55; P for trend = .01). Similarly, for the development of retinal hard exudates, the RR for the top vs bottom quintile of hsCRP level was 1.78 (95% CI, 0.98-3.25; P for trend = .004), whereas for ICAM-1 level, the RR comparing the top vs bottom quintiles was 1.50 (95% CI, 0.84-2.68; P for trend = .05). There were no statistically significant associations between baseline VCAM-1 or tumor necrosis factor α receptor 1 levels and risk of any of the DR end points.

CONCLUSIONS AND RELEVANCE

After adjusting for known risk factors, increasing quintiles of baseline hsCRP level may be associated with higher risk of incident CSME and macular hard exudate in the DCCT cohort. Circulating levels of ICAM-1 may also be associated with the development of retinal hard exudates.

Inhibition of islet immunoreactivity by adiponectin is attenuated in human type 1 diabetes

CONTEXT

Adiponectin is an adipocyte-derived cytokine with insulin-sensitizing and antiinflammatory properties. These dual actions have not previously been examined in the context of human disease.

OBJECTIVES

Our objective was to examine the adiponectin axis in type 1 diabetes (T1D). T1D is an autoimmune inflammatory disease resulting from pancreatic β-cell destruction, in which insulin resistance associates with progression to disease.

DESIGN, PATIENTS, AND INTERVENTIONS

We measured circulating adiponectin and adiponectin receptor expression on blood-immune cells from 108 matched healthy, T1D, and type 2 diabetic subjects. We tested adiponectin effect on T cell proliferation to islet antigens and antigen-presenting function of monocyte-derived dendritic cells (mDCs). Lastly, we assessed the effect of a 3-week lifestyle intervention program on immune cell adiponectin receptor expression in 18 healthy subjects.

RESULTS

Circulating concentrations of adiponectin were not affected by T1D. However, expression of adiponectin receptors on blood monocytes was markedly reduced and inversely associated with insulin resistance. Reduced adiponectin receptor expression resulted in increased T cell proliferation to islet-antigen presented by autologous mDCs. We demonstrated a critical role for adiponectin in down-regulating the costimulatory molecule CD86 on mDCs, and this function was impaired in T1D. We proceeded to show that lifestyle intervention increased adiponectin receptor but reduced CD86 expression on monocytes.

CONCLUSIONS

These data indicate that T cells are released from the antiinflammatory effects of adiponectin in T1D and suggest a mechanism linking insulin resistance and islet immunity. Furthermore, we suggest that interventions that reduce insulin resistance could modulate the inflammatory process in T1D.

Biomarkers in diabetes: hemoglobin A1c, vascular and tissue markers

Biomarkers are conventionally defined as "biological molecules that represent health and disease states." They typically are measured in readily available body fluids (blood or urine), lie outside the causal pathway, are able to detect subclinical disease, and are used to monitor clinical and subclinical disease burden and response to treatments. Biomarkers can be "direct" endpoints of the disease itself, or "indirect" or surrogate endpoints. New technologies (such as metabolomics, proteomics, genomics) bring a wealth of opportunity to develop new biomarkers. Other new technologies enable the development of nonmolecular, functional, or biophysical tissue-based biomarkers. Diabetes mellitus is a complex disease affecting almost every tissue and organ system, with metabolic ramifications extending far beyond impaired glucose metabolism. Biomarkers may reflect the presence and severity of hyperglycemia (ie, diabetes itself) or the presence and severity of the vascular complications of diabetes. Illustrative examples are considered in this brief review. In blood, hemoglobin A1c (HbA1c) may be considered as a biomarker for the presence and severity of hyperglycemia, implying diabetes or prediabetes, or, over time, as a "biomarker for a risk factor," ie, hyperglycemia as a risk factor for diabetic retinopathy, nephropathy, and other vascular complications of diabetes. In tissues, glycation and oxidative stress resulting from hyperglycemia and dyslipidemia lead to widespread modification of biomolecules by advanced glycation end products (AGEs). Some of these altered species may serve as biomarkers, whereas others may lie in the causal pathway for vascular damage. New noninvasive technologies can detect tissue damage mediated by AGE formation: these include indirect measures such as pulse wave analysis (a marker of vascular dysfunction) and more direct markers such as skin autofluorescence (a marker of long-term accumulation of AGEs). In the future, we can be optimistic that new blood and tissue-based biomarkers will enable the detection, prevention, and treatment of diabetes and its complications long before overt disease develops.

The effect of intensive risk factor management in type 2 diabetes on inflammatory biomarkers

AIMS

To determine whether intensive risk factor management reduced markers of inflammation in middle-aged and older people with type 2 diabetes who either had, or were at risk for cardiovascular disease (CVD), and whether these effects were mediated by adiposity.

METHODS

The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial was a multicenter double 2 by 2 factorial randomized controlled trial of 10,251 middle-aged and older people who had type 2 diabetes, a GHbA1c of 7.5% or greater, and evidence of CVD or CVD risk factors. Biomarkers were assessed in a subset of 562 participants. Intervention effects on high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) were tested using linear regression models.

RESULTS

A significantly lower average hs-CRP was noted in the intensive versus the standard glycemic group (p=0.029). Adjusting for change in BMI or waist circumference resulted in larger differences in adjusted hs-CRP (p<0.001 and p<0.002, respectively) between the glycemic intervention groups.

CONCLUSIONS

Intensive glycemic control was associated with a reduction in hs-CRP in this study population. Intervention associated increases in adiposity suppressed the beneficial effect of intensive glycemic control on lowering hs-CRP.

Obesity and coronary artery calcium in diabetes: the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study

BACKGROUND

The aim was to examine whether excess weight is associated with coronary artery calcium (CAC), independent of metabolic parameters in adults with type 1 diabetes (T1D).

METHODS

Subjects between 19 and 56 years of age with T1D (n=621) from the Coronary Artery Calcification in Type 1 Diabetes study were classified as abnormal on four metabolic parameters: blood pressure ≥130/85 mm Hg or on antihypertensive treatment; high-density lipoprotein-cholesterol of <40 mg/dL for men or <50 mg/dL for women; triglycerides of ≥150 mg/dL; or C-reactive protein of ≥3 μg/mL. Study participants with two or more abnormal parameters were classified as metabolically abnormal. Weight categories by body mass index were normal (<25 kg/m(2)), overweight (25 to <30 kg/m(2)), and obese (≥30 kg/m(2)). CAC was measured at two visits 6.0±0.5 years apart. Progression of CAC was defined as an increase in square root transformed CAC volume of ≥2.5 mm(3) or development of clinical coronary artery disease.

RESULTS

Among subjects with T1D, 48% of normal, 61% of overweight, and 73% of obese participants were classified as metabolically abnormal (P<0.0001). Overweight and obesity were independently associated with presence of CAC, independent of presence of metabolically abnormal. Obesity but not overweight was associated with CAC progression, independent of the other cardiovascular risk factors.

CONCLUSIONS

Although obesity is known to increase cardiovascular disease risk through inducing metabolic abnormalities such as dyslipidemia, hypertension, and inflammation, it is also a strong predictor of subclinical atherosclerosis progression in adults with T1D independent of these factors.

Chronic insulin therapy reduces adipose tissue macrophage content in LDL-receptor-deficient mice

AIMS/HYPOTHESIS

Insulin has anti-inflammatory effects in short-term experiments. However, the effects of chronic insulin administration on inflammation are unknown. We hypothesised that chronic insulin administration would beneficially alter adipose tissue inflammation and several circulating inflammatory markers.

METHODS

We administered two forms of long-acting insulin, insulin glargine (A21Gly,B31Arg,B32Arg human insulin) and insulin detemir (B29Lys[ε-tetradecanoyl],desB30 human insulin), to LDL-receptor-deficient mice. After 8 weeks on a diet that causes obesity, hyperglycaemia, adipose tissue macrophage accumulation and atherosclerosis, the mice received subcutaneous glargine, detemir or NaCl (control) for 12 weeks. Serum amyloid A (SAA) and serum amyloid P (SAP), metabolic variables, adipose tissue macrophages and aortic atherosclerosis were evaluated.

RESULTS

Weight gain was equivalent in all groups. The glycated haemoglobin level fell equivalently in both insulin-treated groups. Plasma cholesterol and triacylglycerol levels, and hepatic triacylglycerol level significantly improved in the glargine compared with the detemir or control groups. Levels of mRNA expression for monocyte chemotactic protein-1 and F4/80, a macrophage marker, in adipose tissue were decreased only in the glargine group (p < 0.05). Visceral adipose tissue macrophage content decreased in both insulin groups (p < 0.05), whereas atherosclerosis decreased only in the glargine group. Circulating SAA and SAP did not decrease in either insulin-treated group, but IL-6 levels fell in the glargine-treated mice.

CONCLUSIONS/INTERPRETATION

While chronic insulin administration did not decrease SAA and SAP, administration of glargine but not detemir insulin improved dyslipidaemia, IL-6 levels and atherosclerosis, and both insulins reduced macrophage accumulation in visceral adipose tissue. Thus, chronic insulin therapy has beneficial tissue effects independent of circulating inflammatory markers in this murine model of diet-induced obesity and diabetes.

Autoimmune-mediated vascular injury occurs prior to sustained hyperglycemia in a murine model of type I diabetes mellitus

BACKGROUND

Accelerated cardiovascular disease in patients with type I diabetes (TID) is a well-described condition and serious clinical obstacle. At present, the notion that early atherogenesis is largely dependent on sustained hyperglycemia remains in question. We hypothesize that an alteration in T lymphocyte homeostasis may result in early vascular inflammation, which might amplify subsequent blood vessel injury in euglycemia.

METHODS

A murine model of carotid arterial ligation was employed to induce neointimal hyperplasia (NIH) in C57/Bl6 (non-autoimmune) and non-obese diabetic (NOD) mice. Additionally, adoptive transfer of NOD splenocytes into immunodeficient NOD mice (NOD.scid) was undertaken to evaluate the influence of restored autoimmunity on NIH development.

RESULTS

Interestingly, compared with C57/Bl6 mice, the NOD demonstrate a significant increase in neointimal area. Conversely, the NOD.scid mice (immunodeficient control) reveal almost no evidence of vascular injury. While evidence of early vascular inflammation can be detected in the injured NOD vasculature, uninjured contralateral vessels and those of the NOD.scid have minimal T cell infiltration. Following reconstitution of autoimmune responses via NOD splenocyte adoptive transfer, accelerated vascular pathology is restored.

CONCLUSIONS

These observations suggest that autoimmunity, in the setting of impending hyperglycemia, may contribute to accelerated vascular inflammation and subsequent pathology.

Chromium dinicocysteinate supplementation can lower blood glucose, CRP, MCP-1, ICAM-1, creatinine, apparently mediated by elevated blood vitamin C and adiponectin and inhibition of NFkappaB, Akt, and Glut-2 in livers of zucker diabetic fatty rats

Chromium and cysteine supplementation can improve glucose metabolism in animal studies. This study examined the hypothesis that a cysteinate complex of chromium is significantly beneficial than either of them in lowering blood glucose and vascular inflammation markers in Zucker diabetic fatty (ZDF) rats. Starting at the age of 6 wk, ZDF rats were supplemented orally (daily gavages for 8 more weeks) with saline-placebo (D) or chromium (400 microg Cr/Kg body weight) as chromium dinicocysteinate (CDNC), chromium dinicotinate (CDN) or chromium picolinate (CP) or equimolar L-cysteine (LC, img/Kg body weight), and fed Purina 5008 diet for 8 wk. ZDF rats of 6 wk age before any supplementations and onset of diabetes were considered as baseline. D rats showed elevated levels of fasting blood glucose, HbA(1), CRP, MCP-1, ICAM-1 and oxidative stress (lipid peroxidation) and lower adiponectin and vitamin C, when compared with baseline rats. In comparison to D group, CDNC group had significantly lower blood glucose, HbA(1), CRP, MCP-1, ICAM-1 and lipid peroxidation and increased vitamin C and adiponectin levels. CDN, CP or LC showed significantly less or no effect on these biomarkers. Only CDNC lowered blood creatinine levels in comparison to D. While CDN and CP had no effect, activation of NFkappaB, Akt and glucose transporter-2 levels were decreased, insulin receptor substrate 1 (IRS-1) activation increased in livers of CDNC-rats. CDNC effect on glycemia, NFkappaB, Akt and IRS-1 in liver was significantly greater compared with LC. Blood chromium levels did not differ between Cr-groups. Exogenous vitamin C supplementation significantly inhibited MCP-1 secretion in U937 monocytes cultured in high-glucose-medium. CDNC is a potent hypoglycemic compound with anti-inflammatory activity apparently mediated by elevated blood vitamin C and adiponectin and inhibition of NFkappaB, Akt, and Glut-2 and increased IRS-1 activation in livers of type 2 diabetic rats.

Evolution of pancreas transplant surgery

BACKGROUND

Type 1 diabetes mellitus is a chronic condition often leading to disabling complications including retinopathy, neuropathy and cardiovascular disease which can be modified by intensive treatment with insulin. Such treatment, however, is associated with a restrictive lifestyle and risk of hypoglycaemic morbidity and mortality.

METHODS

This review examines the role of pancreas transplantation in patients with Type 1 diabetes mellitus.

RESULTS

Pancreas transplantation is currently the only proven option to achieve long-term insulin independence, resulting in an improvement or stabilization of those diabetic related complications. The hazards of pancreas transplantation as a major operation are well known. Balancing the risks of a surgical procedure, with the benefits of restoring normoglycaemia remains an important task for the pancreas transplant surgeon. Pancreas transplantation is not an emergency operation to treat poorly managed and non-compliant patients with debilitating complications. It is a highly specialized procedure which has evolved both in terms of the surgical technique, patient selection and assessment.

CONCLUSION

Pancreas transplantation has emerged as the single most effective way to achieve normal glucose homeostasis in patients with Type 1 diabetes mellitus.

Effect of acute hyperglycaemia, long-term glycaemic control and insulin on endothelial dysfunction and inflammation in Type 1 diabetic patients with different characteristics

OBJECTIVE

To investigate the possibility of reversing endothelial dysfunction and inflammation by glucose normalization, antioxidants and insulin per se, in different subgroups of Type 1 diabetic patients.

METHODS

Three subgroups of Type 1 diabetic patients were studied: patients within 1 month of diagnosis (subgroup 1); patients with approximately 5 years' disease duration and with glycated haemoglobin (HbA(1c)) <or= 7.0% (subgroup 2) or > 7.0% since diagnosis (subgroup 3). Participants underwent four procedures: 2-h hyperglycaemic clamp followed by: (A) 12 h near-normalization of blood glucose, with the addition of vitamin C during the last 6 h; (B) 12-h vitamin C and near-normalization of blood glucose for the last 6 h; (C) both vitamin C and near-normalization of blood glucose for 12 h; (D) hyperglycaemic-hyperinsulinaemic clamp for 12 h, with the addition of vitamin C during the last 6 h.

RESULTS

After 2 h of hyperglycaemia, markers of endothelial dysfunction, nitrotyrosine, 8-iso prostaglandin F2alpha, soluble intercellular adhesion molecule-1, soluble vascular adhesion molecule-1, interleukin (IL)-6 and IL-18 were increased in all the subgroups. Levels were normalized, at all time points, by treatments A, B and C in the subgroups 1 and 2. In the third subgroup, levels were normalized only by the simultaneous normalization of blood glucose and vitamin C treatment. During treatment D, the levels were improved at 6 h in all the subgroups, but normalized at 12 h only after vitamin C in subgroups 1 and 2, but not in subgroup 3.

CONCLUSIONS

This study suggests that different subgroups of Type 1 diabetic patients react identically to acute hyperglycaemia and insulin, but differently to glucose normalization.

Association between mannose-binding lectin, high-sensitivity C-reactive protein and the progression of diabetic nephropathy in type 1 diabetes

AIMS/HYPOTHESIS

Diabetic nephropathy has been associated with low-grade inflammation and activation of the complement system in cross-sectional studies. Data from prospective studies are sparse. We investigated the associations of the complement activator mannose-binding lectin (MBL) and the inflammatory marker high-sensitivity C-reactive protein (hsCRP) with the development of nephropathy in a large prospective study of patients with type 1 diabetes from the Finnish Diabetic Nephropathy (FinnDiane) Study.

METHODS

Baseline MBL and hsCRP were measured in 1,564 type 1 diabetes patients from the FinnDiane study, of whom 1,010 had a normal albumin excretion rate, 236 had microalbuminuria and 318 had macroalbuminuria. The main outcome was progression in renal disease during follow-up.

RESULTS

Both baseline MBL (p = 0.038) and hsCRP (p < 0.001) increased with increasing level of albuminuria. During 5.8 +/- 2.2 years of follow-up, progression to a higher albuminuria level or end-stage renal disease (ESRD) occurred in 201 patients. MBL levels were higher in progressors compared with non-progressors at all steps of progression, and in a covariate adjusted multivariate Cox-regression analysis MBL levels above the median were significantly associated with progression from macroalbuminuria to ESRD (hazard ratio 1.88, 95% CI 1.06-3.32, p = 0.030). In a univariate analysis, hsCRP levels above the median were significantly associated with progression from normal albumin excretion rate to microalbuminuria, but the association was only borderline significant after adjustment for covariates (hazard ratio 1.56, 95% CI 0.97-2.51, p = 0.068).

CONCLUSIONS/INTERPRETATION

This study demonstrates that concentrations of both MBL and hsCRP are associated with the progression of renal disease in type 1 diabetes.

[Reliability of the classification of nutritional status obtained through the BMI and three different methods of body fat percentage in patients with type 1 diabetes mellitus]

OBJECTIVE

To assess the reliability of classification of nutritional status (NS) obtained through the body mass index (BMI) and three different methods of body composition (BC) in individuals type 1 diabetics (T1D) and non-diabetic subjects.

METHODS

84 patients with T1D and 37 controls were evaluated. Anthropometric data was collected to calculate BMI and assessment of BC was performed through the methods of skinfold thickness (SF), bipolar (BI) and tetrapolar (TT) bioelectrical impedance. The agreement between the scores of each method was determined by Kappa (K) coefficient.

RESULTS

Considering all the patients, only 48 (57.1%) presented classification of BMI that agreed with the SF method, 58 (69%) with the BI and 45 (53.5%) with the TT. The K results for individuals with T1D was DC = 0.261, BI = 0.320 and TT = 0.174. The controls had higher values (DC = 0.605, BI = 0.360 and TT = 0.400). However, all values were considered low.

CONCLUSIONS

The method of BMI showed little sensitivity to BC changes in patients with T1D. Appropriated methods for the assessment of BC should be used to classify the NS of this population.

Nonenzymatic glycation impairs the antiinflammatory properties of apolipoprotein A-I

OBJECTIVE

The goal of this study was to investigate the effects of nonenzymatic glycation on the antiinflammatory properties of apolipoprotein (apo) A-I.

METHODS AND RESULTS

Rabbits were infused with saline, lipid-free apoA-I from normal subjects (apoA-I(N)), lipid-free apoA-I nonenzymatically glycated by incubation with methylglyoxal (apoA-I(Glyc in vitro)), nonenzymatically glycated lipid-free apoA-I from subjects with diabetes (apoA-I(Glyc in vivo)), discoidal reconstituted high-density lipoproteins (rHDL) containing phosphatidylcholine and apoA-I(N), (A-I(N))rHDL, or apoA-I(Glyc in vitro), (A-I(Glyc in vitro))rHDL. At 24 hours postinfusion, acute vascular inflammation was induced by inserting a nonocclusive, periarterial carotid collar. The animals were euthanized 24 hours after the insertion of the collar. The collars caused intima/media neutrophil infiltration and increased endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). ApoA-I(N) infusion decreased neutrophil infiltration and VCAM-1 and ICAM-1 expression by 89%, 90%, and 66%, respectively. The apoA-I(Glyc in vitro) infusion decreased neutrophil infiltration by 53% but did not reduce VCAM-1 or ICAM-1 expression. ApoA-I(Glyc in vivo) did not inhibit neutrophil infiltration or adhesion molecule expression. (A-I(Glyc in vitro))rHDL also inhibited vascular inflammation less effectively than (A-I(N))rHDL. The reduced antiinflammatory properties of nonenzymatically glycated apoA-I were attributed to a reduced ability to inhibit nuclear factor-kappaB activation and reactive oxygen species formation.

CONCLUSIONS

Nonenzymatic glycation impairs the antiinflammatory properties of apoA-I.

Resistance of retinal inflammatory mediators to suppress after reinstitution of good glycemic control: novel mechanism for metabolic memory

Diabetic retinopathy resists arrest of its progression after reestablishment of good glycemic control that follows a profound period of poor glycemic control. The objective of this study was to elucidate the role of inflammation in the resistance of retinopathy to arrest after termination of hyperglycemia. Streptozotocin-diabetic rats were (a) maintained either in poor glycemic control [PC group; glycated hemoglobin (GHb)>11%] or in good glycemic control (GC group; GHb<7%) for 12 months or (b) allowed to be in poor glycemic control for 6 months followed by good glycemic control for 6 additional months. At 12 months, retina was analyzed for pro-inflammatory mediators. Twelve months of PC increased retinal interleukin 1beta (IL-1beta) mRNA by 2-fold and its protein expression by 25% compared with the values obtained from normal rat retina. Tumor necrosis factor alpha (TNF-alpha) was elevated approximately 3-fold (both mRNA and protein), and the receptors for IL-1beta and TNF-alpha were increased by 40% each. The concentrations of intercellular cell adhesion molecule 1 and vascular cell adhesion molecule 1 were elevated by 40% and 150%, respectively, and inducible nitric oxide synthase transcripts were elevated by 6-fold. Six months of good glycemic control that followed 6 months of poor glycemic control failed to reverse the elevations in IL-1beta, TNF receptor type I, and intercellular cell adhesion molecule 1 but had some beneficial effects on TNF-alpha, inducible nitric oxide synthase, and vascular cell adhesion molecule 1, however these mediators remained significantly elevated. However, the GC group showed no significant change in the retinal pro-inflammatory mediators compared with the normal rats. Failure to reverse retinal inflammatory mediators supports their important role in the resistance of retinopathy to arrest after cessation of hyperglycemia.

Nitric oxide and superoxide dismutase modulate endothelial progenitor cell function in type 2 diabetes mellitus

BACKGROUND

The function of endothelial progenitor cells (EPCs), which are key cells in vascular repair, is impaired in diabetes mellitus. Nitric oxide (NO) and reactive oxygen species can regulate EPC functions. EPCs tolerate oxidative stress by upregulating superoxide dismutase (SOD), the enzyme that neutralizes superoxide anion (O2-). Therefore, we investigated the roles of NO and SOD in glucose-stressed EPCs.

METHODS

The functions of circulating EPCs from patients with type 2 diabetes were compared to those from healthy individuals. Healthy EPCs were glucose-stressed, and then treated with insulin and/or SOD. We assessed O2- generation, NO production, SOD activity, and their ability to form colonies.

RESULTS

EPCs from diabetic patients generated more O2-, had higher NAD(P)H oxidase and SOD activity, but lower NO bioavailability, and expressed higher mRNA and protein levels of p22-phox, and manganese SOD and copper/zinc SOD than those from the healthy individuals. Plasma glucose and HbA1c levels in the diabetic patients were correlated negatively with the NO production from their EPCs. SOD treatment of glucose-stressed EPCs attenuated O2- generation, restored NO production, and partially restored their ability to form colonies. Insulin treatment of glucose-stressed EPCs increased NO production, but did not change O2- generation and their ability to form colonies. However, their ability to produce NO and to form colonies was fully restored after combined SOD and insulin treatment.

CONCLUSION

Our data provide evidence that SOD may play an essential role in EPCs, and emphasize the important role of antioxidant therapy in type 2 diabetic patients.

The Diabetes Control and Complications Trial: the gift that keeps giving

The Diabetes Control and Complications Trial (DCCT) recruited its first patients in 1983. In 1993, the investigators reported that intensive glycemic treatment of patients with type 1 diabetes mellitus was superior to conventional therapy in preventing the development of microvascular and neurological complications and thus provided definitive proof of the relationship between hyperglycemia and the subsequent risk of diabetic retinopathy, nephropathy and neuropathy. The value of this study, however, did not end there. After the original trial, most participants of the DCCT continued to be followed up in the Epidemiology of Diabetes Interventions and Complications (EDIC) study, which demonstrated the long-term benefits of close glycemic control and provided observational data of a large epidemiological cohort of patients with type 1 diabetes mellitus. Stored samples from the DCCT have also provided an invaluable resource for the identification of new markers of the disease. Recently, the complete dataset of the DCCT and of the initial years of the EDIC have been made publicly available, which allowed independent investigators to help answer their own questions about diabetes. In conclusion, the DCCT continues to provide new insights into type 1 diabetes mellitus, which are of benefit to patients over a quarter of a century after the trial was started.

Plasma PAF-acetylhydrolase activity, inflammatory markers and susceptibility of LDL to in vitro oxidation in patients with type 1 diabetes mellitus

AIMS

We evaluated if type 1 diabetic patients have altered levels of low-grade inflammatory markers including platelet-activating factor acetylhydrolase (PAF-AH) activity, high-sensitivity C-reactive protein (hs-CRP), white blood cells count (WBC), erythrocyte sedimentation rate (ESR) and LDL-cholesterol oxidation coefficient (OxC), and whether their levels are related to clinical complications and the metabolic profile.

METHODS

We studied cross-sectionally 118 outpatients with type 1 diabetes both with (n=38) and without (n=80) clinical chronic complications, and 110 controls subjects.

RESULTS

Diabetic patients had higher levels of PAF-AH activity (p=0.02), hs-CRP (p=0.001), WBC (p=0.004) and ESR (p=0.0001) than controls. Patients with type 1 diabetes had earlier OxC than the non-diabetic subjects at 1 and 3 h (p=0.01) after the addition of CuSO(4). No difference was noted between patients with and without chronic complications. In the patients, correlations were found between PAF-AH activity and OxC at 1 and 3 h.

CONCLUSIONS

It was concluded that the susceptibility of LDL to in vitro oxidation and low-grade inflammation are increased in patients with type 1 diabetes and related to each other. The presence of these markers is probably independent of the presence of chronic clinical complications and reveals the development of early pro-inflammatory state.

L-cysteine supplementation lowers blood glucose, glycated hemoglobin, CRP, MCP-1, and oxidative stress and inhibits NF-kappaB activation in the livers of Zucker diabetic rats

This study examined the hypothesis that l-cysteine supplementation can lower insulin resistance, glycemia, oxidative stress, and markers of vascular inflammation in type 2 diabetes using Zucker diabetic fatty (ZDF) rats as a model. Starting at the age of 6 weeks, ZDF rats were supplemented orally (daily gavage, 8 weeks) with saline placebo (D) or l-cysteine (LC; 1 mg/kg bw) and fed a high-calorie diet. Six-week-old rats without any supplementation were considered baseline (BL) rats. D rats showed elevated fasting blood glucose, glycated Hb, CRP, and MCP-1 compared with BL rats in which there was no onset of diabetes. LC supplementation significantly lowered blood levels of glucose (18%, p= 0.05), glycated Hb (8%, p= 0.02), CRP (23%, p= 0.02), MCP-1 (32%, p= 0.01), and insulin resistance (25%) compared with levels seen in saline-supplemented D rats. There was a decrease in plasma protein oxidation levels (p< 0.01); however, GSH levels were similar in LC and D groups. Although LC did not change blood hematocrit or levels of transaminases, it did lower alkaline phosphatase (29%, p= 0.01) levels in comparison to D. Western blotting analyses of liver showed increased activation of NF-kappaB and Akt (50% pNF-kappaB and 20% pAkt) in D compared with BL rats. LC supplementation inhibited these effects (17% pAkt, 18% pNF-kappaB). This is the first report showing that l-cysteine supplementation can lower glycemia and markers of vascular inflammation in diabetes apparently by preventing NF-kappaB activation in a diabetic animal model.

Association of diet with glycated hemoglobin during intensive treatment of type 1 diabetes in the Diabetes Control and Complications Trial

BACKGROUND

Persons with type 1 diabetes have received widely varying dietary advice based on putative effects on glycemic control.

OBJECTIVE

The objective was to determine whether diet composition was associated with subsequent glycated hemoglobin (Hb A1c) concentrations during intensive therapy for type 1 diabetes.

DESIGN

We examined associations between quantiles of dietary intake and Hb A1c adjusted for age and sex in 532 intensively treated participants in the Diabetes Control and Complications Trial (DCCT) who had complete dietary data through 5 y of follow-up. Multivariate macronutrient density linear regression models tested the association of Hb A1c at year 5 with macronutrient composition and were adjusted for age, sex, exercise, triglyceride concentration, body mass index (BMI), baseline Hb A1c, and concurrent insulin dose.

RESULTS

Higher insulin dose, lower carbohydrate intake, and higher saturated, monounsaturated, and total fat intakes were associated with higher Hb A1c concentrations at year 5. In age- and sex-adjusted multivariate macronutrient models, substitution of fat for carbohydrate was associated with higher Hb A1c concentrations (P = 0.01); this relation remained significant after adjustment for exercise level, serum triglycerides, and BMI (P = 0.02) but was no longer significant (P = 0.1) after adjustment for baseline Hb A1c and concurrent insulin dose.

CONCLUSION

Among intensively treated patients with type 1 diabetes, diets higher in fat and saturated fat and lower in carbohydrate are associated with worse glycemic control, independent of exercise and BMI.

Inflammation and progressive nephropathy in type 1 diabetes in the diabetes control and complications trial

OBJECTIVE

Progressive nephropathy represents a substantial source of morbidity and mortality in type 1 diabetes. Increasing albuminuria is a strong predictor of progressive renal dysfunction and heightened cardiovascular risk. Early albuminuria probably reflects vascular endothelial dysfunction, which may be mediated in part by chronic inflammation.

RESEARCH DESIGN AND METHODS

We measured baseline levels of four inflammatory biomarkers (high-sensitivity C-reactive protein, soluble intercellular adhesion molecule-1 [sICAM-1], soluble vascular cell adhesion molecule-1, and soluble tumor necrosis factor-alpha receptor-1) in stored blood samples from the 1,441 participants of the Diabetes Control and Complication Trial (DCCT). We used mixed-effects regression models to determine the average annual change in urinary albumin excretion rate (AER) by tertiles of each biomarker. We also used Cox proportional hazards models to estimate the relative risk of incident sustained microalbuminuria according to levels of each biomarker.

RESULTS

After adjustment for baseline age, sex, duration of diabetes, A1C, and randomized treatment assignment, we observed a significantly higher 5.9 microg x min(-1) x year(-1) increase in AER among those in the highest compared with the lowest tertile of baseline sICAM-1 (P = 0.04). Those in the highest tertile of sICAM-1 had an adjusted relative risk of 1.67 (95% CI 0.96-2.92) of developing incident sustained microalbuminuria (P(trend) = 0.03).

CONCLUSIONS

Higher baseline sICAM-1 levels predicted an increased risk of progressive nephropathy in type 1 diabetes and may represent an early risk marker that reflects the important role of vascular endothelial dysfunction in this long-term complication.