Glucose intake induces an increase in activator protein 1 and early growth response 1 binding activities, in the expression of tissue factor and matrix metalloproteinase in mononuclear cells, and in plasma tissue factor and matrix metalloproteinase concentrations

Diabetes and pancreatic cancer

Type 2 diabetes mellitus is likely the third modifiable risk factor for pancreatic cancer after cigarette smoking and obesity. Epidemiological investigations have found that long-term type 2 diabetes mellitus is associated with a 1.5-fold to 2.0-fold increase in the risk of pancreatic cancer. A causal relationship between diabetes and pancreatic cancer is also supported by findings from prediagnostic evaluations of glucose and insulin levels in prospective studies. Insulin resistance and associated hyperglycemia, hyperinsulinemia, and inflammation have been suggested to be the underlying mechanisms contributing to development of diabetes-associated pancreatic cancer. Signaling pathways that regulate the metabolic process also play important roles in cell proliferation and tumor growth. Use of the antidiabetic drug metformin has been associated with reduced risk of pancreatic cancer in diabetics and recognized as an antitumor agent with the potential to prevent and treat this cancer. On the other hand, new-onset diabetes may indicate subclinical pancreatic cancer, and patients with new-onset diabetes may constitute a population in whom pancreatic cancer can be detected early. Biomarkers that help define high-risk individuals for clinical screening for pancreatic cancer are urgently needed. Why pancreatic cancer causes diabetes and how diabetes affects the clinical outcome of pancreatic cancer have yet to be fully determined. Improved understanding of the pathological mechanisms shared by diabetes and pancreatic cancer would be the key to the development of novel preventive and therapeutic strategies for this cancer.

Effects of acute ingestion of different fats on oxidative stress and inflammation in overweight and obese adults

Background

Studies show that obese individuals have prolonged elevations in postprandial lipemia and an exacerbated inflammatory response to high fat meals, which can increase risk for cardiovascular diseases. As epidemiological studies indicate an association between type of fat and circulating inflammatory markers, the purpose of this study was to investigate the acute effect of different fat sources on inflammation and oxidative stress in overweight and obese individuals.

Methods

Eleven overweight and obese subjects consumed three high fat milkshakes rich in monounsaturated fat (MFA), saturated fat (SFA), or long-chain omega 3 polyunsaturated fat (O3FA) in random order. Blood samples collected at baseline, 1, 2, 4, and 6 hours postprandial were analyzed for markers of inflammation (soluble intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), tumor necrosis factor- α (TNF-α), and C-reactive protein (CRP)), oxidative stress (8-epi-prostaglandin-F2α (8-epi) and nuclear factor-κB (NF-κB)), and metabolic factors (glucose, insulin, non-esterified free fatty acids, and triglycerides (TG)).

Results

O3FA enhanced NF-kB activation compared to SFA, but did not increase any inflammatory factors measured. Conversely, SFA led to higher ICAM-1 levels than MFA (p = 0.051), while MFA increased TG more than SFA (p < 0.05). CRP increased while TNF-α and 8-epi decreased with no difference between treatments.

Conclusions

While most of the inflammatory factors measured had modest or no change following the meal, ICAM-1 and NF-κB responded differently by meal type. These results are provocative and suggest that type of fat in meals may differentially influence postprandial inflammation and endothelial activation.

Effects of glycemic regulation on chronic postischemia pain

BACKGROUND

Ischemia-reperfusion (I/R) injuries consist of enhanced oxidative and inflammatory responses along with microvascular dysfunction after prolonged ischemia and reperfusion. Because I/R injuries induce chronic postischemia pain (CPIP) in laboratory animals, it is possible that surgical procedures using prolonged ischemia may result in chronic postoperative pain. Glycemic modulation during ischemia and reperfusion could affect pain after I/R injury because glucose triggers oxidative, inflammatory, and thrombotic reactions, whereas insulin has antioxidative, antiinflammatory, and vasodilatory properties.

METHODS

One hundred ten rats underwent a 3-h period of ischemia followed by reperfusion to produce CPIP. Rats with CPIP had previously been divided into six groups with differing glycemic modulation paradigms: normal feeding; fasting; fasting with normal saline administration; fasting with dextrose administration; normal feeding with insulin administration; and normal feeding with insulin and dextrose administration. Blood glucose concentration was assessed during I/R in these separate groups of rats, and these rats were tested for mechanical and cold allodynia over the 21 days afterward (on days 2, 5, 7, 9, 12, and 21 after I/R injury).

RESULTS

I/R injury in rats with normoglycemia or relative hyperglycemia (normal feeding and fasting with dextrose administration groups) led to significant mechanical and cold allodynia; conversely, relative hypoglycemia associated with insulin treatment or fasting (fasting, fasting with normal saline administration, and normal feeding with insulin administration groups) reduced allodynia induced by I/R injury. Importantly, insulin treatment did not reduce allodynia when administered to fed rats given dextrose (normal feeding with dextrose and insulin administration group).

CONCLUSION

Study results suggest that glucose levels at the time of I/R injury significantly modulate postinjury pain thresholds in rats with CPIP. Strict glycemic control during I/R injury significantly reduces CPIP and, conversely, hyperglycemia significantly enhances it, which could have potential clinical applications especially in the surgical field.

Differentially expressed genes in human peripheral blood as potential markers for statin response

There is a considerable inter-individual variation in response to statin therapy and one third of patients do not meet their treatment goals. We aimed to identify differentially expressed genes that might be involved in the effects of statin treatment and to suggest potential markers to guide statin therapy. Forty-six healthy Korean subjects received atorvastatin; their whole-genome expression profiles in peripheral blood were analyzed before and after atorvastatin administration in relation with changes in lipid profiles. The expression patterns of the differentially expressed genes were also compared with the data of familial hypercholesterolemia (FH) patients and controls. Pairwise comparison analyses revealed differentially expressed genes involved in diverse biological processes and molecular functions related with immune responses. Atorvastain mainly affected antigen binding, immune or inflammatory response including interleukin pathways. Similar expression patterns of the genes were observed in patients with FH and controls. The Charcol-Leyden crystal (CLC), CCR2, CX3CR1, LRRN3, FOS, LDLR, HLA-DRB1, ERMN, and TCN1 genes were significantly associated with cholesterol levels or statin response. Interestingly, the CLC gene, which was significantly altered by atorvastatin administration and differentially expressed between FH patients and controls, showed much bigger change in high-responsive group than in low-responsive group. We identified differentially expressed genes that might be involved in mechanisms underlying the known pleiotropic effects of atorvastatin, baseline cholesterol levels, and drug response. Our findings suggest CLC as a new candidate marker for statin response, and further validation is needed.

An oat bran meal influences blood insulin levels and related gene sets in peripheral blood mononuclear cells of healthy subjects

The understanding of how fibre-rich meals regulate molecular events at a gene level is limited. This pilot study aimed to investigate changes in gene expression in peripheral blood mononuclear cells (PBMCs) from healthy subjects after consumption of an oat bran-rich meal. Fifteen subjects (8 men and 7 women, aged 20-28 years) ingested meals with oat bran or a control meal after an overnight fast. Blood samples for analysis of postprandial glucose, insulin and triglyceride concentrations were taken during 3 h, while PBMCs for microarray gene expression profiling from five men and five women were taken before and 2 h after the meal. Analysis of transcriptome data was performed with linear mixed models to determine differentially expressed genes in response either to meal intake or meal content, and enrichment analysis was used to identify functional gene sets responding to meal intake and specifically to oat bran intake. Meal intake as such affected gene expression for genes mainly involved in metabolic stress; indicating increased inflammation due to the switch from fasting to fed state. The oat bran meal affected gene sets associated with a lower insulin level, compared with the control meal. The gene sets included genes involved in insulin secretion and β-cell development, but also protein synthesis and genes related to cancer diseases. The oat bran meal also significantly lowered postprandial blood insulin IAUC compared to control. Further studies are needed to compare these acute effects with the long-term health effects of oat bran.

Anti-inflammatory effects of serum isolated from animals on intermittent feeding in C6 glioma cell line

Multiple sclerosis (MS) is a demyelinating disease of the CNS. Early inflammation leads to later destruction of myelin in MS. Dietary restriction (DR) produces anti-inflammatory and immunomodulatory effects in many species. Based on the reported anti-inflammatory effects of DR, we investigated whether sera collected from rats fed on intermittent feeding (IF, a type of DR) diet could modulate cytokine secretion and matrix metalloproteinase (MMP-2) activity that are involved in MS pathogenesis. Cytokine levels (IL-6 and TGF-β1) were measured in supernatant from C6 glioma cell line cultures treated with IF and AL fed animals' sera by enzyme-linked immunosorbent assay (ELISA) and MMP-2 activity was detected by gelatin zymography. Our results indicated that sera of animals on IF diet significantly reduced IL-6 (p<0.05) and increased TGF-β1 (p<0.05) production by C6 glioma cells. A significant decrease (p<0.05) in MMP-2 activity was also found. These results indicate anti-inflammatory and immunomodulatory activity in the sera of animals on IF regimen on cells involved in multiple sclerosis pathogenesis. Further studies on the detection of factors responsible for such activities and their mechanism of action in MS pathogenesis are recommended.

Influence of macronutrient intake and anthropometric characteristics on plasma insulin after eccentric exercise

To increase understanding of the interaction between macronutrients and insulin resistance (IR), this study sought to determine the influence of macronutrient intake and anthropometric differences on IR and inflammation responses to eccentric resistance exercise. Men and women (n = 12, 19-36 years old) participated in a crossover study and completed 6 sets of 10 unilateral maximal eccentric contractions of the elbow flexors and extensors followed by controlled diet conditions for the first 8 hours postexercise of carbohydrate/fat/protein proportions of either 75%/15%/10% (CHO) or 6%/70%/24% (FAT/PRO). Fasting glucose, insulin, homeostatic model assessment (HOMA) variables, and interleukin (IL)-1β were measured preexercise and 23 hours postexercise (additional measures of glucose and insulin 1 hour after meals consumed 0.5, 3, and 7 hours postexercise). Insulin increased more (P < .01) in the CHO compared with the FAT/PRO condition at 1.5, 4, and 8 hours postexercise. Insulin, HOMA-IR, and HOMA-β-cell function increased 23 hours postexercise in both conditions, whereas IL-1β increased 23 hours postexercise only in the CHO condition. Magnitude of change (Δ) for these variables associated positively with body mass index (BMI) and waist to hip ratio (WHR) in the CHO and inversely in the FAT/PRO condition; that is, r = 0.53 (P = .10) and r = -0.82 (P < .01) for BMI vs Δ insulin in CHO and FAT/PRO conditions, respectively. The Δ IL-1β associated with BMI (r = 0.62, P < .05) and WHR (r = 0.84, P < .01) in the CHO condition. The CHO enhanced IR and inflammation as BMI and WHR increased, whereas fat and protein enhanced IR as BMI and WHR decreased. Thus, BMI and WHR may need to be taken into account in the development of nutritional strategies to prevent IR.

Macronutrient intake induces oxidative and inflammatory stress: potential relevance to atherosclerosis and insulin resistance

With the global increase in the epidemic of obesity and type 2 diabetes with a concomitant increase in atherosclerotic disease, an investigation into the effects of various macronutrients and food products has become necessary. Such investigation will allow us to better understand the relationship between the intake of various macronutrients and the pathogenesis of mechanisms underlying the regulation of insulin sensitivity and resistance, oxidative stress and inflammation, the regulation of hunger and satiety and atherogenesis. This review covers the first decade of work in this area relating the intake of usual foods and diets to their immediate and long term outcomes. The review also covers the exciting novel area of anti-inflammatory effects of certain foods. Hopefully, a comprehensive understanding of these actions of macronutrients and their long term effects will allow us to formulate food combinations which will lead to healthy eating habits and improvement in our overall health status.

Bench-to-bedside review: Glucose and stress conditions in the intensive care unit

The physiological response to blood glucose elevation is the pancreatic release of insulin, which blocks hepatic glucose production and release, and stimulates glucose uptake and storage in insulin-dependent tissues. When this first regulatory level is overwhelmed (that is, by exogenous glucose supplementation), persistent hyperglycaemia occurs with intricate consequences related to the glucose acting as a metabolic substrate and as an intracellular mediator. It is thus very important to unravel the glucose metabolic pathways that come into play during stress as well as the consequences of these on cellular functions. During acute injuries, activation of serial hormonal and humoral responses inducing hyperglycaemia is called the 'stress response'. Central activation of the nervous system and of the neuroendocrine axes is involved, releasing hormones that in most cases act to worsen the hyperglycaemia. These hormones in turn induce profound modifications of the inflammatory response, such as cytokine and mediator profiles. The hallmarks of stress-induced hyperglycaemia include 'insulin resistance' associated with an increase in hepatic glucose output and insufficient release of insulin with regard to glycaemia. Although both acute and chronic hyperglycaemia may induce deleterious effects on cells and organs, the initial acute endogenous hyperglycaemia appears to be adaptive. This acute hyperglycaemia participates in the maintenance of an adequate inflammatory response and consequently should not be treated aggressively. Hyperglycaemia induced by an exogenous glucose supply may, in turn, amplify the inflammatory response such that it becomes a disproportionate response. Since chronic exposure to glucose metabolites, as encountered in diabetes, induces adverse effects, the proper roles of these metabolites during acute conditions need further elucidation.

Obesity in children and adolescents: the relation between metabolic syndrome and non-alcoholic fatty-liver disease

This article aims to review clinical and diagnostic aspects of non-alcoholic fatty liver disease associated with obesity and its relation to metabolic syndrome in children and adolescents. An on-line search was carried out of original articles in the Medical Literature Analysis and Retrieval System Online (MEDLINE), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) and Scientific Eletronic Library Online (SciELO) databases, using the following key words: "hepatic steatosis", "nonalcoholic fatty liver diseases", "overweight", "obesity", "children", "adolescents", "ultrasound" and "metabolic syndrome" in English and Portuguese. Two hundred and seventy-five articles were initially selected, all published between 1993 and 2008. After reading this was narrowed down to 67. The literature consulted revealed no consensus regarding the need to screen for metabolic syndrome and non-alcoholic fatty liver disease, especially in obese children and adolescents and those who have excess fat in the abdominal region. An ultrasound examination of the liver is typically used for screening and, in the case of children who present alterations in aminotransferases in addition to fatty infiltration of the liver, a strict clinical follow-up and a liver biopsy are recommended if these symptoms do not disappear on treatment.

Orange juice neutralizes the proinflammatory effect of a high-fat, high-carbohydrate meal and prevents endotoxin increase and Toll-like receptor expression

BACKGROUND

The intake of glucose or a high-fat, high-carbohydrate (HFHC) meal, but not orange juice, induces an increase in inflammation and oxidative stress in circulating mononuclear cells (MNCs) of normal-weight subjects.

OBJECTIVE

We investigated the effect of orange juice on HFHC meal-induced inflammation and oxidative stress and the expression of plasma endotoxin and Toll-like receptors (TLRs).

DESIGN

Three groups (10 subjects in each group) of normal, healthy subjects were asked to drink water or 300 kcal glucose or orange juice in combination with a 900-kcal HFHC meal. Blood samples were obtained before and 1, 3, and 5 h after the drinks and meal combinations were consumed.

RESULTS

Protein expression of the NADPH oxidase subunit p47(phox), phosphorylated and total p38 mitogen-activated protein kinase, and suppressor of cytokine signaling-3; TLR2 and TLR4 messenger RNA (mRNA) and protein expression; mRNA expression of matrix metalloproteinase (MMP)-9 in MNCs; and plasma concentrations of endotoxin and MMP-9 increased significantly after glucose or water were consumed with the meal but not when orange juice was consumed with the meal. The generation of reactive oxygen species by polymorphonuclear cells was significantly lower when orange juice was added to the meal than when water or glucose was added to the meal.

CONCLUSIONS

The combination of glucose or water and the HFHC meal induced oxidative and inflammatory stress and an increase in TLR expression and plasma endotoxin concentrations. In contrast, orange juice intake with the HFHC meal prevented meal-induced oxidative and inflammatory stress, including the increase in endotoxin and TLR expression. These observations may help explain the mechanisms underlying postprandial oxidative stress and inflammation, pathogenesis of insulin resistance, and atherosclerosis.

Insulin-heparin infusions peritransplant substantially improve single-donor clinical islet transplant success

BACKGROUND

Successful islet transplantation can result in insulin independence in many patients with type 1 diabetes mellitus, but it often requires more than one islet infusion. The ability to achieve insulin independence with a single donor is an important goal in clinical islet transplantation due to the limited organ supply.

METHODS

We examined factors that may be associated with insulin independence after islet transplantation with islets from a single donor, using univariate and multivariate analysis.

RESULTS

Thirteen of 85 (15.3%) achieved insulin independence after single-donor islet transplantation. Using multivariate analysis, only the use of insulin and heparin infusions peritransplant was a significant factor associated with insulin independence, with an adjusted odds ratio of 8.6 (95% confidence interval 2.0-37.0). Patients who had received insulin and heparin infusions peritransplant had greater indices of islet engraftment and a greater reduction in insulin use (80.1% + or - 4.3% vs. 54.2% + or - 2.8%, P<0.001) even if insulin independence was not achieved.

CONCLUSIONS

Peritransplant intensive insulin and heparin enhances islet transplantation outcomes likely related in part to mitigation of the effects of the instant blood-mediated inflammatory reaction, combined with islet rest and avoidance of inflammation. It would be important to further investigate the effects of peritransplant insulin and heparin infusions on islet engraftment.

Inflammatory lipid mediators in adipocyte function and obesity

Survival of multicellular organisms depends on their ability to fight infection, metabolize nutrients, and store energy for times of need. Unsurprisingly, therefore, immunoregulatory and metabolic mechanisms interact in human conditions such as obesity. Both infiltrating immunoinflammatory cells and adipocytes play critical roles in the modulation of metabolic homeostasis, so it is important to understand factors that regulate both adipocyte and immune cell function. A currently favored paradigm for obesity-associated metabolic dysfunction is that chronic macronutrient and/or lipid overload (associated with adiposity) induces cellular stress that initiates and perpetuates an inflammatory cycle and pathophysiological signaling of immunoinflammatory cells and adipocytes. Many lipid mediators exert their biological effects by binding to cognate receptors, such as G-protein-coupled receptors and Toll-like receptors. This process is tightly regulated under normal physiological conditions, and any disruption can initiate disease processes. Observations that cellular lipid loading (associated with adiposity) initiates inflammatory events has encouraged studies on the role of lipid mediators. In this review, we speculate that lipid mediators act on important immune receptors to induce low-grade tissue inflammation, which leads to adipocyte and metabolic dysfunction.

Hyperglycemia in critical illness: a review

Hyperglycemia is commonplace in the critically ill patient and is associated with worse outcomes. It occurs after severe stress (e.g., infection or injury) and results from a combination of increased secretion of catabolic hormones, increased hepatic gluconeogenesis, and resistance to the peripheral and hepatic actions of insulin. The use of carbohydrate-based feeds, glucose containing solutions, and drugs such as epinephrine may exacerbate the hyperglycemia. Mechanisms by which hyperglycemia cause harm are uncertain. Deranged osmolality and blood flow, intracellular acidosis, and enhanced superoxide production have all been implicated. The net result is derangement of endothelial, immune and coagulation function and an association with neuropathy and myopathy. These changes can be prevented, at least in part, by the use of insulin to maintain normoglycemia.

Association between oxidized LDL, obesity and type 2 diabetes in a population-based cohort, the Health, Aging and Body Composition Study

BACKGROUND

Accumulating evidence suggests a cross-sectional association between oxidative stress and type 2 diabetes (T2D). Systemic oxidative stress, as measured by oxidized LDL (oxLDL), has been correlated with visceral fat. We examined the relationship between oxLDL, and T2D- and obesity-related traits in a bi-racial sample of 2985 subjects at baseline and after 7 years of follow-up.

METHODS

We examined six T2D-related traits (T2D status, HbA(1c), fasting glucose, insulin, adiponectin and HOMA-IR) as well as six obesity-related traits (obesity status, BMI, leptin, % body fat, visceral and subcutaneous fat mass) using logistic and linear regression models.

RESULTS

In all subjects at baseline, oxLDL was positively associated with T2D (OR = 1.3, 95% CI:1.1-1.5), fasting glucose (ss = 0.03 +/- 0.006), HbA(1c) (ss = 0.02 +/- 0.004), fasting insulin (ss = 0.12 +/- 0.02), HOMA-IR (ss = 0.13 +/- 0.02) and negatively with adiponectin (ss = -0.16 +/- 0.03), (all p < 0.001). The strength and magnitude of these associations did not differ much between blacks and whites. In both blacks and whites, oxLDL was also associated with obesity (OR = 1.3, 95% CI:1.1-1.4) and three of its related traits (ss = 0.60 +/- 0.14 for BMI, ss = 0.74 +/- 0.17 for % body fat, ss = 0.29 +/- 0.06 for visceral fat; all p < 0.001). Furthermore, of four traits measured after 7 years of follow-up (fasting glucose, HbA1c, BMI and % fat), their relationship with oxLDL was similar to baseline observations. No significant association was found between oxLDL and incident T2D. Interestingly, oxLDL was significantly associated with % change in T2D- and obesity-related traits in whites but not in blacks.

CONCLUSION/INTERPRETATION

Our data suggest that systemic oxidative stress may be a novel risk factor for T2D and obesity.

An overview of glycemic control in the coronary care unit with recommendations for clinical management

The observation that elevated glucose occurs frequently in the setting of acute myocardial infarction was made decades ago. Since then numerous studies have documented that hyperglycemia is a powerful risk factor for increased mortality and in-hospital complications in patients with acute coronary syndromes. While some questions in this field have been answered in prior investigations, many critical gaps in knowledge continue to exist and remain subjects of intense debate. This review summarizes what is known about the relationship between hyperglycemia, glucose control, and outcomes in critically ill patients with acute coronary syndromes, addresses the gaps in knowledge and controversies, and offers general recommendations regarding glucose management in the coronary care unit.

Relationship between perioperative glycemic control and postoperative infections

Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormalities in leukocyte function, including granulocyte adherence, impaired phagocytosis, delayed chemotaxis, and depressed bactericidal capacity. These leukocyte deficiencies are the cause of infection and improve with tight glycemic control, which leads to fewer POIs in critically ill surgical patients. Tight glycemic control, such as intensive insulin therapy, has a risk of hypoglycemia. In addition, the optimal targeted blood glucose range to reduce POI remains unknown. Since 2006, we have investigated tight perioperative blood glucose control using a closed-loop artificial endocrine pancreas system, to reduce POI and to avoid hypoglycemia. In this Topic Highlight, we review the relationship between perioperative glycemic control and POI, including the use of the artificial pancreas.

[Role of diet on chronic inflammation prevention and control - current evidences]

It is known that low chronic inflammation occurs in several stages of non transmissible chronic diseases, including cardiovascular diseases, obesity and diabetes mellitus, among others. Observational studies and clinical trials indicate that diet plays an important role in the reduction of such diseases. The present manuscript discusses the studies that linked diet macronutrient composition and the levels of inflammatory markers. It has been suggested that the consumption of high glycemic index diets, which have low fiber content and are rich in trans fat cause the activation of the immune system, leading to excessive production of pro-inflammatory mediators and the reduction of the anti-inflammatory ones. Although the results are controversial, healthy dietary intakes with the reduction in fat intake (especially trans and saturated fat) and the increase in fruits, vegetables, and whole grain consumption seem to be associated with the improvement in subclinical inflammatory condition.

Elevated admission glucose and mortality in elderly patients hospitalized with heart failure

BACKGROUND

Although some professional societies recommend target-driven glucose control for all hospitalized patients, the association between elevated glucose and adverse outcomes has not been well established in patients hospitalized with heart failure.

METHODS AND RESULTS

We evaluated a nationally representative cohort of 50,532 elderly patients hospitalized with heart failure in the United States between April 1998 and June 2001. The association between admission glucose and all-cause mortality at 30 days and 1 year was analyzed with multivariable Cox regression models, both in the entire cohort and in patients with and without diabetes mellitus. After multivariable adjustment, no significant relationship was found between glucose and 30-day mortality (for glucose groups of >110 to 140, >140 to 170, >170 to 200, and >200 mg/dL; hazard ratios for 30-day mortality were 1.09 (95% confidence interval, 0.98 to 1.22), 1.27 (95% confidence interval, 1.11 to 1.45), 1.16 (95% confidence interval, 0.98 to 1.37), and 1.00 (95% confidence interval, 0.87 to 1.15), respectively, versus glucose < or =110 mg/dL; P for linear trend=0.53). Results were similar for 1-year mortality and did not differ between patients with and without known diabetes mellitus (for diabetesxglucose interaction, P=0.11 and 0.55 for 30-day and 1-year mortality, respectively).

CONCLUSIONS

We found no significant association between admission glucose levels and mortality in a large cohort of patients hospitalized with heart failure. Our findings suggest that the relationship between hyperglycemia and adverse outcomes seen in acute myocardial infarction cannot be automatically extended to patients hospitalized with other cardiovascular conditions.

Insulin as an anti-inflammatory and antiatherogenic modulator

Data demonstrate the anti-inflammatory effects of insulin and proinflammatory effects of glucose. These data provide a mechanistic justification for the benefits of maintaining euglycemia with insulin infusions in hospitalized patients. Regimens that infuse fixed doses of insulin with high rates of glucose are usually associated with hyperglycemia, which may neutralize the beneficial effects of insulin. Therefore, we propose that such regimens should be avoided and instead replaced by insulin infusions that normalize and maintain blood glucose at a reasonably low level and ensure that plasma insulin is maintained at levels high enough to provide clinically relevant anti-inflammatory and cardioprotective effects. Trials to test this hypothesis are in progress.

Genetic determinants and molecular pathways in the pathogenesis of Type 2 diabetes

T2DM (Type 2 diabetes mellitus) has reached epidemic proportions worldwide, exerting major health consequences at an individual and public health level alike. Unfortunately, the molecular pathophysiology of diabetes remains incompletely understood, impairing progress towards more effective prevention and treatment strategies. Although the rapid increase in the prevalence of insulin resistance and T2DM over the past several decades highlights a major environmental contribution related to overnutrition, obesity and inactivity, susceptibility is likely to reflect individual differences in complex gene-environment interactions. In the present review, we focus on mediators of genetic and environmental risk for T2DM at a molecular level.

Confirming a biological pathway in the metabolic syndrome--insight from the NHANES 1999-2002

The objective of this study was to examine the role of obesity in the development of the metabolic syndrome (MS). A total of 3,596 whites aged 19 years and above, who participated in the National Health and Nutrition Examination Survey (NHANES) 1999-2002, were included for analysis. Anthropometric measurements, biochemical profiles, and high-sensitivity C-reactive protein (CRP) were measured. A structural equation model (SEM) was constructed to elucidate a pathway in which obesity initiated the cascade leading to full MS. The results of SEM demonstrated that obesity was positively associated with elevated CRP level (B = 0.05, P < 0.001). This higher inflammatory state directed to insulin resistance (B = 0.32, P < 0.001), which in turn was positively associated with dyslipidemia (B = 0.06, P < 0.001). Obesity could also directly and positively affect blood pressure (B = 0.51, P < 0.001), without the mediation of insulin resistance and/or inflammation. The results of the cross-sectional analysis in the white subjects have shown that obesity has a strong influence on hypertension that obtains little additional influence from inflammation or insulin resistance. The metabolic profile in the NHANES group has been confirmatory with the statement that there is a sequential effect from obesity to inflammation, insulin resistance, and dyslipidemia. This approach has allowed to inferring important biological insights about the nature of the relationships among the components of MS.

Inhibition of transcriptional activity of c-JUN by SIRT1

c-JUN is a major component of heterodimer transcription factor AP-1 (Activator Protein-1) that activates gene transcription in cell proliferation, inflammation and stress responses. SIRT1 (Sirtuin 1) is a histone deacetylase that controls gene transcription through modification of chromatin structure. However, it is not clear if SIRT1 regulates c-JUN activity in the control of gene transcription. Here, we show that SIRT1 associated with c-JUN in co-immunoprecipitation of whole cell lysate, and inhibited the transcriptional activity of c-JUN in the mammalian two hybridization system. SIRT1 was found in the AP-1 response element in the matrix metalloproteinase-9 (MMP9) promoter DNA leading to inhibition of histone 3 acetylation as shown in a ChIP assay. The SIRT1 signal was reduced by the AP-1 activator PMA, and induced by the SIRT1 activator Resveratrol in the promoter DNA. SIRT1-mediaetd inhibition of AP-1 was demonstrated in the MMP9 gene expression at the gene promoter, mRNA and protein levels. In mouse embryonic fibroblast (MEF) with SIRT1 deficiency (SIRT1(-/-)), mRNA and protein of MMP9 were increased in the basal condition, and the inhibitory activity of Resveratrol was significantly attenuated. Glucose-induced MMP9 expression was also inhibited by SIRT1 in response to Resveratrol. These data consistently suggest that SIRT1 directly inhibits the transcriptional activity of AP-1 by targeting c-JUN.

[Microcirculation in diabetes: implications for chronic complications and treatment of the disease]

Diabetic microangiopathy is responsible for an important rate of morbidity and mortality related to the disease. Endothelial damage seems to be the triggering factor in the pathogenesis of microvascular complications. Diabetes mellitus and other metabolic diseases are associated to endothelial dysfunction, the most precocious known marker of atherosclerosis. Changes on microvascular reactivity are present in patients with diabetes mellitus, as well as in individuals with risk factors for this disease. Evaluation of endothelial and microvascular functions is possible using different invasive or preferentially non-invasive methods. Adequate control of diabetes mellitus might postpone or perhaps even prevent the microvascular disease. Microvascular dysfunction, when seen only by changes on microvascular reactivity, could be ameliorated with correction of risk factors or drug treatment.

A functional role of gelatinase A in the development of nutritionally induced obesity in mice

BACKGROUND

Development of adipose tissue is a complex process involving adipogenesis, angiogenesis and proteolytic remodeling of the extracellular matrix. The matrix metalloproteinase (MMP) system plays an important role in these processes.

OBJECTIVE

To establish a functional role of gelatinase A (MMP-2) in the development of adipose tissue.

METHODS

Mice with genetic deficiency in gelatinase A (MMP-2(-/-)) and their wild-type littermates (MMP-2(+/+)), as well as wild-type mice treated with a gelatinase inhibitor, were kept on a high-fat diet (HFD) for 15 weeks, and this was followed by analysis of weight and composition of the fat pads.

RESULTS

MMP-2(-/-) mice gained significantly (P < 0.05) less weight on the HFD than MMP-2(+/+) mice, resulting in lower body weights (P < 0.0005). The weights of the isolated subcutaneous and gonadal adipose tissues were also significantly lower (P < 0.005 and P < 0.0005, respectively). Immunohistochemical analysis revealed significant (P < 0.05) adipocyte hypotrophy in both fat pads. Treatment of wild-type mice with the gelatinase inhibitor Tolylsam resulted in an approximately 15% reduction of body weight (P < 0.0001) and significantly lower subcutaneous and gonadal adipose tissue mass, associated with adipose hypotrophy (all P < 0.0001).

CONCLUSION

Deficiency of MMP-2 impairs adipose tissue development in mice by contributing to adipocyte hypotrophy.

Effect of insulin glulisine on microvascular blood flow and endothelial function in the postprandial state

OBJECTIVE

To investigate the effect of insulin glulisine on postprandial microvascular blood flow in type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 15 patients with type 2 diabetes received insulin glulisine or human insulin before a liquid meal test. Thereafter, skin microvascular blood flow was measured by laser Doppler fluxmetry and blood samples were taken for measurement of plasma levels of glucose, insulin, intact proinsulin, asymmetric dimethylarginine, nitrotyrosine, interleukin-18, matrix metalloproteinase-9, oxidized LDL, and free fatty acids.

RESULTS

Insulin glulisine injections resulted in higher postprandial insulin levels (means +/- SEM area under the curve [AUC](0-120) 51.0 +/- 6.8 vs. 38.2 +/- 5.4 mU/l; P = 0.004), while plasma glucose (AUC(0-240) 158 +/- 9 vs. 180 +/- 9 mg/dl; P < 0.05) and intact proinsulin (AUC(0-240) 26.2 +/- 3.5 vs. 31.2 +/- 4.3 pmol/l; P = 0.002) were lower. Microvascular blood flow increased after insulin glulisine injection (27.9 +/- 3.1 to 51.7 +/- 9.9 arbitrary units [AU]; P < 0.05), while only a minor increase was found during human insulin (27.9 +/- 3.1 to 34.4 +/- 7.8 AU; not significant). Asymmetric dimethylarginine and nitrotyrosine levels were reduced after insulin glulisine (P < 0.05).

CONCLUSIONS

Insulin glulisine is superior to human insulin in restoring postprandial metabolic and microvascular physiology.

Inflammation markers are modulated by responses to diets differing in postprandial insulin responses in individuals with the metabolic syndrome

BACKGROUND

Inflammation may be a mechanism by which high postprandial insulin and glucose responses increase the risk of type 2 diabetes mellitus.

OBJECTIVE

We hypothesized that dietary carbohydrates characterized by different postprandial insulin responses may differentially modify cytokine concentrations in plasma and gene expression in subcutaneous adipose tissue.

DESIGN

Individuals (n = 47) with the metabolic syndrome were randomly assigned to a 12-wk diet with oat and wheat bread and potato (high postprandial insulin response) or rye bread and pasta (low postprandial insulin response). Postprandial glucose and insulin responses to the oat and wheat bread meal and to the rye bread meal were determined in 19 individuals before intervention.

RESULTS

During the 12-wk diet, the change in the gene expression of interleukin (IL)-10 receptor alpha and tumor necrosis factor-alpha in subcutaneous adipose tissue differed between the groups (P = 0.002 and P = 0.083, respectively). Moreover, the change in fasting plasma concentrations of IL-1beta and IL-6 differed between the groups (P = 0.020 and P = 0.055, respectively). In the postprandial challenge, the insulin response to the rye bread meal was lower than that to the oat and wheat bread meal (P < 0.001), whereas there were no differences in the mean blood glucose response. In contrast, plasma glucose concentrations decreased more below fasting concentrations 2.5-3 h after the oat and wheat bread meal than after the rye bread meal. A late postprandial rebound of free fatty acids was detected after the oat and wheat bread meal (P = 0.048).

CONCLUSIONS

Long-term intake of cereal foods with differing postprandial insulin responses may be a factor that modulates the inflammatory status in individuals with the metabolic syndrome.

Use of insulin to improve glycemic control in diabetes mellitus

BACKGROUND

The restoration of normoglycemia ensures the control of diabetic symptoms and reduction in microangiopathic complications in type 1 and type 2 diabetes. However, there is no conclusive evidence that intensive glycemic control alone will prevent macrovascular disease, the commonest cause of morbidity and mortality in type 2 diabetes. As atherosclerosis is an inflammatory condition, it is relevant that the two common insulin resistant states of obesity and type 2 diabetes have significant inflammatory processes, which promote atherosclerosis. It is also relevant that glucose has been shown to have profound effects on the endothelial cell, the leukocyte and the platelet. These effects include the induction of acute oxidative and inflammatory stress and a prothrombotic and pro-apoptotic effect following glucose intake. In contrast insulin has been shown to exert several biological effects at physiologically relevant concentrations, in relation to the endothelial cell, the platelet and leucocyte function, which may be cardioprotective and potentially anti-atherosclerotic.

CONCLUSION

These findings are of great interest as it is possible that the prevention of macrovascular complications in type 2 diabetes may require the use of those glucose lowering drugs which have additional anti-inflammatory effects in addition to the control of comorbid conditions (hypertension and dyslipidemia) associated with this disease. Results of future clinical trials are awaited to confirm the benefits of this approach in the primary and secondary prevention of macrovascular complications in type 2 diabetes.

Hyperglycemia and acute coronary syndrome: a scientific statement from the American Heart Association Diabetes Committee of the Council on Nutrition, Physical Activity, and Metabolism

Hyperglycemia is common and associated with markedly increased mortality rates in patients hospitalized with acute coronary syndromes (ACS). Despite the fact that several studies have documented this association, hyperglycemia remains underappreciated as a risk factor, and it is frequently untreated in ACS patients. This is in large part due to limitations of prior studies, and the remaining critical gaps in our understanding of the relationship between hyperglycemia and poor outcomes. The main objective of the present statement is to summarize the current state of knowledge regarding the association between elevated glucose and patient outcomes in ACS and to outline the most important knowledge gaps in this field. These gaps include the need to specifically define hyperglycemia, develop optimal ways of measuring and tracking glucose values during ACS hospitalization, and better understand the physiological mechanisms responsible for poor outcomes associated with hyperglycemia. The most important issue, however, is whether elevated glucose is a direct mediator of adverse outcomes in ACS patients or just a marker of greater disease severity. Given the marked increase in short- and long-term mortality associated with hyperglycemia, there is an urgent need for definitive large randomized trials to determine whether treatment strategies aimed at glucose control will improve patient outcomes and to define specific glucose treatment targets. Although firm guidelines will need to await completion of these clinical trials, the present statement also provides consensus recommendations for hyperglycemia management in patients with ACS on the basis of the available data.

Glucometrics in patients hospitalized with acute myocardial infarction: defining the optimal outcomes-based measure of risk

BACKGROUND

Hyperglycemia on admission is associated with an increased mortality rate in patients with acute myocardial infarction. Whether metrics that incorporate multiple glucose assessments during acute myocardial infarction hospitalization are better predictors of mortality than admission glucose alone is not well defined.

METHODS AND RESULTS

We evaluated 16,871 acute myocardial infarction patients hospitalized from January 2000 to December 2005. Using logistic regression models and C indexes, 3 metrics of glucose control (mean glucose, time-averaged glucose, hyperglycemic index), each evaluated over 3 time windows (first 24 hours, 48 hours, entire hospitalization), were compared with admission glucose for their ability to discriminate hospitalization survivors from nonsurvivors. Models were then used to evaluate the relationship between mean glucose and in-hospital mortality. All average glucose metrics performed better than admission glucose. The ability of models to predict mortality improved as the time window increased (C indexes for admission, mean 24 hours, 48 hours, and hospitalization glucose were 0.62, 0.64, 0.66, 0.70; P<0.0001). Statistically significant but small differences in C indexes of mean glucose, time-averaged glucose, and hyperglycemic index were seen. Mortality rates increased with each 10-mg/dL rise in mean glucose > or = 120 mg/dL (odds ratio, 1.8; P=0.003 for glucose 120 to < 130 mg/dL) and with incremental decline < 70 mg/dL (odds ratio, 6.4; P=0.01 versus glucose 100 to < 110 mg/dL). The slope of these relationships was steeper in patients without diabetes.

CONCLUSIONS

Measures of persistent hyperglycemia during acute myocardial infarction are better predictors of mortality than admission glucose. Mean hospitalization glucose appears to be the most practical metric of hyperglycemia-associated risk. A J-shaped relationship exists between average glucose and mortality, with both persistent hyperglycemia and hypoglycemia associated with adverse prognosis.

Does increased oxidative stress cause hypertension?

Hypertension is associated with increased vascular oxidative stress; however, there is still a debate whether oxidative stress is a cause or a result of hypertension. Animal studies have generally supported the hypothesis that increased blood pressure is associated with increased oxidative stress; however, human studies have been inconsistent. Oxidative stress promotes vascular smooth muscle cell proliferation and hypertrophy and collagen deposition, leading to thickening of the vascular media and narrowing of the vascular lumen. In addition, increased oxidative stress may damage the endothelium and impair endothelium-dependent vascular relaxation and increases vascular contractile activity. All these effects on the vasculature may explain how increased oxidative stress can cause hypertension. Treatment with antioxidants has been suggested to lower oxidative stress and therefore blood pressure. However, to date, clinical studies investigating antioxidant supplements have failed to show any consistent benefit. It is noteworthy that lowering blood pressure with antihypertensive medications is associated with reduced oxidative stress. Therefore, it seems that oxygen stress is not the cause, but rather a consequence, of hypertension.

Effect of modified glucose-insulin-potassium on free fatty acids, matrix metalloproteinase, and myoglobin in ST-elevation myocardial infarction

Insulin has a free fatty acid (FFA)-suppressive effect, vascular endothelial growth factor (VEGF)- and matrix metalloproteinase (MMP)-lowering effect, and a potential myocardial-protective effect. Whether low-dose insulin exerts these effects in patients with acute myocardial infarction (MI) was investigated. Thirty-two patients administered thrombolytics and heparin were randomly assigned to a modified glucose-insulin-potassium (GIK) regimen (insulin 2.5 U/hour, dextrose and potassium titrated to prevent hyperglycemia) or normal saline solution and potassium (controls) for 48 hours. Plasma FFA, serum VEGF, pro-MMP-1, and myoglobin were measured at baseline and sequentially for 48 hours. FFA concentrations were increased at baseline; increased further in the first 4 hours in controls (p<or=0.008), but not in the GIK group, and were higher at 4 hours in controls compared with the GIK group (p=0.0009). VEGF decreased to 7% of baseline at 2 hours and remained suppressed in both groups (p=0.0008). Pro-MMP-1 decreased in both groups (p<0.005), but this decrease was seen earlier at 2 hours in the GIK group compared with 4 hours in controls. There was no significant increase in myoglobin at 2 hours in the GIK group, whereas there was a significant increase in controls. Mean blood glucose was 131 mg/dl in controls and 124 mg/dl in the GIK group (p=NS). In conclusion, this modified GIK regimen attenuated the increase in FFA, but did not suppress it to less than the threshold for myocardial FFA uptake. It suppressed pro-MMP-1 rapidly and decreased myoglobin, whereas heparin suppressed VEGF in patients with acute MI. This provided additional rationale for conducting a trial to assess the clinical benefits of this modified GIK regimen in patients with acute MI.

Prolonged reactive oxygen species generation and nuclear factor-kappaB activation after a high-fat, high-carbohydrate meal in the obese

BACKGROUND

Because obesity is associated with chronic oxidative and inflammatory stress, and high-fat, high-carbohydrate meals induce significant oxidative and inflammatory stress in normal subjects, we have now hypothesized that the intake of a high-fat, high-carbohydrate meal would result in a greater and more prolonged oxidative and inflammatory stress in the obese than in normal subjects.

METHODS

Ten normal-weight and eight obese subjects were given a high-fat, high-carbohydrate meal after an overnight fast. Blood samples were collected at baseline and hourly following the meal for 3 h.

RESULTS

Reactive oxygen species generation by mononuclear cells increased significantly by 2 h in both groups but continued to increase significantly at 3 h in the obese subjects, whereas in normal subjects it returned to baseline. Levels of p47(phox) increased significantly (by 81 +/- 26%) at 3 h in obese individuals (P < 0.05), whereas there was no significant change in p47(phox) in normal subjects. Nuclear factor-kappaB DNA binding in mononuclear cells increased significantly (by 48 +/- 58%, P < 0.036) at 2 h but not at 3 h in normal subjects, whereas in the obese, nuclear factor-kappaB increased significantly at both 2 and 3 h (by 36 +/- 57 and 42 +/- 63%, respectively, P < 0.004). Matrix metalloproteinase-9 concentrations were significantly higher in the obese at baseline (580 +/- 103.9 vs. 373 +/- 30.03 ng/ml, P < 0.05) and increased to significantly greater concentrations after the meal than in the lean subjects.

CONCLUSIONS

High-fat, high-carbohydrate meals induced a significantly more prolonged and greater oxidative and inflammatory stress in the obese. This may contribute to the increased atherogenic risk in obesity.

Obese reproductive-age women exhibit a proatherogenic inflammatory response during hyperglycemia

OBJECTIVE

The objective was to determine if physiological hyperglycemia induces a proatherogenic inflammatory response in mononuclear cells (MNCs) in obese reproductive-age women.

RESEARCH METHODS AND PROCEDURES

Seven obese and 6 age-matched lean women (20 to 39 years of age) underwent a 2-hour 75-g oral glucose tolerance test. The release of interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) from MNCs cultured in the presence of lipopolysaccharide (LPS) was measured after isolation from blood samples drawn fasting and 2 hours after glucose ingestion. Reactive oxygen species (ROS) generation and intra-nuclear nuclear factor kappaB (NFkappaB) from MNCs were quantified from the same blood samples. Insulin resistance was estimated by homeostasis model assessment of insulin resistance (HOMA-IR). Total body fat and truncal fat were determined by DXA.

RESULTS

Obese women had a higher (p < 0.03) total body fat (42.2 +/- 1.1 vs. 27.7 +/- 2.0%), truncal fat (42.1 +/- 1.2 vs. 22.3 +/- 2.4%), and HOMA-IR (3.3 +/- 0.5 vs. 1.8 +/- 0.2). LPS-stimulated IL-6 release from MNCs was suppressed during hyperglycemia in lean subjects (1884 +/- 495 vs. 638 +/- 435 pg/mL, p < 0.05) but not in obese women (1184 +/- 387 vs. 1403 +/- 498 pg/mL). There was a difference (p < 0.05) between groups in the hyperglycemia-induced MNC-mediated release of IL-6 (-1196 +/- 475 vs. 219 +/- 175 pg/mL) and IL-1beta (-79 +/- 43 vs. 17 +/- 12 pg/mL). In addition, the obese group exhibited increased (p < 0.05) MNC-derived ROS generation (39.3 +/- 9.9 vs. -1.0 +/- 12.8%) and intra-nuclear NFkappaB (9.4 +/- 7.3 vs. -23.5 +/- 13.5%). Truncal fat was positively correlated with the MNC-derived IL-6 response (rho = 0.58, p < 0.05) and intra-nuclear NFkappaB (rho = 0.64, p < 0.05).

DISCUSSION

These data suggest that obese reproductive-age women are unable to suppress proatherogenic inflammation during physiological hyperglycemia. Increased adiposity may be a significant contributor to this pro-inflammatory susceptibility.

Analysis of the signal transduction pathway of nickel-induced matrix metalloproteinase-2 expression in the human keratinocytes in vitro: preliminary findings

BACKGROUND

Nickel can induce cellular and nuclear damages responsible for chronic diseases, like allergic contact dermatitis (ACD). We previously showed that matrix metalloproteinase-2 (MMP-2) gene expression was induced by nickel in nontumorigenic human keratinocytes cell line (HaCat).

OBJECTIVE

To investigate the signal transduction pathways involved in gelatinolytic activity induced in HaCat under nickel stimulation.

METHODS

We analyzed the involvement of protein kinase A (PKA), protein kinase C (PKC), tyrosine kinase (PTK), nuclear factor-kB (NF-kB) and activator protein-1 (AP-1) using specific inhibitors (H89, calphostin C, genistein, carpain and curcumin) by electrophoretic mobility shift assay, reverse transcription-polymerase chain reaction and gelatin zymography.

RESULTS

Our results indicate that nickel-induced MMP-2 production was inhibited with PTK, PKC and AP-1 specific inhibitors. Moreover, both PKA and NF-kB were not involved in nickel pathway.

CONCLUSIONS

Using HaCat, we showed that curcumin and genistein can revert nickel-induced MMP-2 upregulation. Whether the use of PTK and AP-1 inhibitors has therapeutic ramifications in the management of ACD remains to be investigated.

Anti-inflammatory effects of insulin

PURPOSE OF REVIEW

This review deals with the recent observations on the pro-inflammatory effects of glucose and the anti-inflammatory actions of insulin. Apart from being novel, they are central to our understanding of why hyperglycemia is a prognosticator of bad clinical outcomes including patients with acute coronary syndromes, stroke and in patients in the intensive care unit.

RECENT FINDINGS

The pro-inflammatory effect of glucose as well as that of other macronutrients including fast food meals provides the basis of chronic oxidative stress and inflammation in the obese and their propensity to atherosclerotic disease. The anti-inflammatory action of insulin provides a neutralizing effect to balance macronutrient induced inflammation on the one hand and the possibility of using insulin as an anti-inflammatory drug on the other.

SUMMARY

The actions of macronutrients and insulin described above explain why insulin resistant states like obesity and type 2 diabetes are associated with oxidative stress, inflammation and atherosclerosis. They also suggest that insulin may be antiatherogenic.

Anti-inflammatory effects of insulin and the pro-inflammatory effects of glucose

Previously published data demonstrate clearly that hyperglycemia worsens morbidity and mortality in patients in intensive care, those with acute myocardial infarction and stroke, and those undergoing coronary artery bypass grafts. The control of hyperglycemia with insulin infusion improves clinical outcomes in all classes of patients mentioned above. In this article we discuss data demonstrating an anti-inflammatory effect of insulin and a pro-inflammatory effect of glucose and free fatty acids and provide a mechanistic justification for the benefits of maintaining euglycemia with insulin infusions in the hospitalized patient. The regimes that infuse fixed doses of insulin with high rates of glucose are usually associated with hyperglycemia. This may neutralize the benefits of insulin. Such regimes should, therefore, be avoided in future and replaced by regimes that infuse insulin to restore and maintain euglycemia.

Effect of hyperglycemia and insulin in acute coronary syndromes

Previously published data clearly demonstrate that hyperglycemia worsens morbidity and mortality in patients in intensive care, those with acute myocardial infarction and stroke, and those undergoing coronary artery bypass grafting. The control of hyperglycemia with insulin infusion improves clinical outcomes in these patients. In this article, we discuss data that demonstrate a proinflammatory effect of glucose and free fatty acids and an anti-inflammatory effect of insulin. We also provide a mechanistic justification for the benefits of maintaining euglycemia with insulin infusion in hospitalized patients.

Orange juice or fructose intake does not induce oxidative and inflammatory response

OBJECTIVE

We have previously shown that 300 kcal from glucose intake induces a significant increase in reactive oxygen species (ROS) generation and nuclear factor-kappaB (NF-kappaB) binding in the circulating mononuclear cells in healthy normal subjects. We hypothesized that the intake of 300 calories as orange juice or fructose, the other major carbohydrate in orange juice, would induce a significantly smaller response than that of glucose.

RESEARCH DESIGN AND METHODS

Four groups (eight subjects each) of normal-weight subjects were given a 300-cal drink of glucose (75 g), fructose (75 g), or orange juice or water sweetened with saccharin (control group) to drink, and then blood samples were collected.

RESULTS

There was a significant increase in ROS generation by mononuclear cells (by 130 +/- 18%, P < 0.001), polymorph nuclear cells (by 95 +/- 22%, P < 0.01), and in NF-kappaB binding in mononuclear cells by 82 +/- 16% (P < 0.01) over the baseline after 2 h of glucose intake. These changes were absent following fructose, orange juice, or water intake. There was significantly lower ROS generation and NF-kappaB binding following orange juice, fructose, and water compared with glucose (P < 0.001 for all). Furthermore, incubation of mononuclear cells in vitro with 50 mmol/l of the flavonoids hesperetin or naringenin reduced ROS generation by 52 +/- 7% and 77 +/- 8% (P < 0.01), respectively, while fructose or ascorbic acid did not cause any change.

CONCLUSIONS

Caloric intake in the form of orange juice or fructose does not induce either oxidative or inflammatory stress, possibly due to its flavonoids content and might, therefore, represent a potentially safe energy source.

Hypertension and the Cardiometabolic Syndrome

Hypertension and cardiovascular disease are leading causes of morbidity and mortality. Accumulating data demonstrate a relationship between hypertension and several vascular and metabolic abnormalities that are components of the cardiometabolic syndrome. The components of the cardiometabolic syndrome include insulin resistance/hyperinsulinemia, central obesity, dyslipidemia, hypertension, microalbuminuria, increased inflammation, and oxidative stress. There is growing evidence that tissue activation of the renin-angiotensin-aldosterone system participates in endothelial dysfunction, microalbuminuria, insulin resistance, and subsequent cardiovascular and chronic kidney disease. The notion that hypertension is a metabolic as well as a vascular disease opens a new paradigm for the treatment of this disorder.

Obesity, inflammation, and insulin resistance

Weight gain and obesity are major risk factors for conditions and diseases ranging from insulin resistance and type 2 diabetes mellitus to atherosclerosis and the sequelae of nonalcoholic fatty liver disease. A chronic, subacute state of inflammation often accompanies the accumulation of excess lipid in adipose tissue and liver (hepatic steatosis), evidenced by changes in both inflammatory cells and biochemical markers of inflammation. These changes can be seen in the involved tissues and systemically, in terms of elevated circulating levels of inflammatory markers. The link between obesity and inflammation has therefore raised the important question of whether obesity-induced inflammation plays a pathogenic role in the development and progression of these disorders. We review the rapidly expanding body of animal and clinical data that support potential roles for inflammation in the pathogenesis of insulin resistance and type 2 diabetes mellitus.