Elevated ambient glucose induces acute inflammatory events in the microvasculature: effects of insulin

Impact of diabetes on epicardial reperfusion and mortality in a contemporary STEMI population undergoing mechanical reperfusion: Insights from the ISACS STEMI COVID 19 registry

BACKGROUND AND AIM

Diabetes has been shown in last decades to be associated with a significantly higher mortality among patients with ST-segment elevation myocardial infarction (STEMI) treated with primary PCI (PPCI). Therefore, the aim of current study was to evaluate the impact of diabetes on times delays, reperfusion and mortality in a contemporary STEMI population undergoing PPCI, including treatment during the COVID pandemic.

METHODS AND RESULTS

The ISACS-STEMI COVID-19 is a large-scale retrospective multicenter registry involving PPCI centers from Europe, Latin America, South-East Asia and North-Africa, including patients treated from 1st of March until June 30, 2019 and 2020. Primary study endpoint of this analysis was in-hospital mortality. Secondary endpoints were postprocedural TIMI 0-2 flow and 30-day mortality. Our population is represented by 16083 STEMI patients. A total of 3812 (23,7 %) patients suffered from diabetes. They were older, more often males as compared to non-diabetes. Diabetic patients were less often active smokers and had less often a positive family history of CAD, but they were more often affected by hypertension and hypercholesterolemia, with higher prevalence of previous STEMI and previous CABG. Diabetic patients had longer ischemia time, had more often anterior MI, cardiogenic shock, rescue PCI and multivessel disease. They had less often out-of-hospital cardiac arrest and in-stent thrombosis, received more often a mechanical support, received less often a coronary stent and DES. Diabetes was associated with a significantly impaired postprocedural TIMI flow (TIMI 0-2: 9.8 % vs 7.2 %, adjusted OR [95 % CI] = 1.17 [1.02-1.38], p = 0.024) and higher mortality (in-hospital: 9.1 % vs 4.8 %, Adjusted OR [95 % CI] = 1.70 [1.43-2.02], p < 0.001; 30-day mortality: 10.8 % vs 6 %, Adjusted HR [95 % CI] = 1.46 [1.26-1.68], p < 0.001) as compared to non-diabetes, particularly during the pandemic.

CONCLUSIONS

Our study showed that in a contemporary STEMI population undergoing PPCI, diabetes is significantly associated with impaired epicardial reperfusion that translates into higher in-hospital and 30-day mortality, particularly during the pandemic.

Acute Hyperglycemia-Induced Injury in Myocardial Infarction

Acute hyperglycemia is a transient increase in plasma glucose level (PGL) frequently observed in patients with ST-elevation myocardial infarction (STEMI). The aim of this review is to clarify the molecular mechanisms whereby acute hyperglycemia impacts coronary flow and myocardial perfusion in patients with acute myocardial infarction (AMI) and to discuss the consequent clinical and prognostic implications. We conducted a comprehensive literature review on the molecular causes of myocardial damage driven by acute hyperglycemia in the context of AMI. The negative impact of high PGL on admission recognizes a multifactorial etiology involving endothelial function, oxidative stress, production of leukocyte adhesion molecules, platelet aggregation, and activation of the coagulation cascade. The current evidence suggests that all these pathophysiological mechanisms compromise myocardial perfusion as a whole and not only in the culprit coronary artery. Acute hyperglycemia on admission, regardless of whether or not in the context of a diabetes mellitus history, could be, thus, identified as a predictor of worse myocardial reperfusion and poorer prognosis in patients with AMI. In order to reduce hyperglycemia-related complications, it seems rational to pursue in these patients an adequate and quick control of PGL, despite the best pharmacological treatment for acute hyperglycemia still remaining a matter of debate.

Nomograms referenced by cardiac magnetic resonance in the prediction of cardiac injuries in patients with ST-elevation myocardial infarction

BACKGROUND

Evaluation of cardiac injuries is essential in patients with ST-elevation myocardial infarction (STEMI). Cardiac magnetic resonance (CMR) has become the gold standard for quantifying cardiac injuries; however, its routine application is limited. A nomogram is a useful tool for prognostic prediction based on the comprehensive utilization of clinical data. We presumed that the nomogram models established using CMR as a reference could precisely predict cardiac injuries.

METHODS

This analysis included 584 patients with acute STEMI from a CMR registry study for STEMI (NCT03768453). The patients were divided into training (n = 408) and testing (n = 176) datasets. The least absolute shrinkage and selection operator method and multivariate logistic regression were used to construct nomograms for predicting left ventricular ejection fraction (LVEF) ≤40%, infarction size (IS) ≥ 20% on the LV mass, and microvascular dysfunction.

RESULTS

The nomogram for predicting LVEF≤40%, IS≥20%, and microvascular dysfunction comprised 14, 10, and 15 predictors, respectively. With the nomograms, the individual risk probability of developing specific outcomes could be calculated, and the weight of each risk factor was demonstrated. The C-index of the nomograms in the training dataset were 0.901, 0.831, and 0.814, respectively, and were comparable in the testing set, showing good nomogram discrimination and calibration. The decision curve analysis demonstrated good clinical effectiveness. Online calculators were also constructed.

CONCLUSIONS

With the CMR results as the reference standard, the established nomograms demonstrated good effectiveness in predicting cardiac injuries after STEMI and could provide physicians with a new option for individual risk stratification.

General Critical Care, Temperature Control, and End-of-Life Decision Making in Patients Resuscitated from Cardiac Arrest

Cardiac arrest affects millions of people per year worldwide. Although advances in cardiopulmonary resuscitation and intensive care have improved outcomes over time, neurologic impairment and multiple organ dysfunction continue to be associated with a high mortality rate. The pathophysiologic mechanisms underlying the post-resuscitation disease are complex, and a coordinated, evidence-based approach to post-resuscitation care has significant potential to improve survival. Critical care management of patients resuscitated from cardiac arrest focuses on the identification and treatment of the underlying cause(s), hemodynamic and respiratory support, organ protection, and active temperature control. This review provides a state-of-the-art appraisal of critical care management of the post-cardiac arrest patient.

Microcirculation-guided treatment improves tissue perfusion and hemodynamic coherence in surgical patients with septic shock

PURPOSE

Severe sepsis and septic shock may impair microcirculatory perfusion and cause organ dysfunction. The aim of this pilot study was to assess a new microcirculation-guided resuscitation strategy in patients with septic shock undergoing emergency abdominal surgery.

METHODS

A microcirculation-guided treatment algorithm was developed and applied intraoperatively following restoration of systemic hemodynamics. Sublingual microcirculation was monitored with Sidestream DarkField (SDF +) imaging technique. The primary objective was to investigate the change in De Backer score, Consensus Proportion of Perfused Vessels (Consensus PPV), and Consensus PPV (small) and its association with venous-to-arterial carbon dioxide difference (v-aPCO₂).

RESULTS

Thirteen consecutive patients were included in the study. Microcirculation-guided resuscitation resulted in an increase of 0.49 mm^-1 in the De Backer score (p < 0.001), an increase of 2.28% in the Consensus PPV (p < 0.001), and an increase of 2.26% in the Consensus PPV (small) (p < 0.001) for every 30 min of additional intraoperative time. All microcirculation variables were negatively correlated with v-aPCO₂ (rho = - 0.656, adj-p < 0.001; rho = - 0.623; adj-p < 0.001; rho = - 0.597, adj-p < 0.001, respectively) at each intraoperative time point. Lactate levels were negatively correlated with Consensus PPV (rho = - 0.464; adj-p = 0.002) and Consensus PPV (small) (rho = - 0.391, adj-p < 0.001). Survival at 30 days, 90 days, and 1 year were 76.9%, 76.9%, and 61.5%, respectively.

CONCLUSIONS

The intraoperative use of microcirculation-guided resuscitation strategy may improve tissue perfusion and hemodynamic coherence in patients with septic shock.

Risk Factors for No-Reflow in Patients with ST-Elevation Myocardial Infarction Who Underwent Percutaneous Coronary Intervention: A Case-Control Study

Methods

This case-control study retrospectively reviewed the medical data of patients treated with primary percutaneous coronary intervention within 12 h after STEMI onset between January 2010 and January 2013 at the Department of Cardiology of the Beijing Anzhen Hospital.

Results

A total of 902 patients were included in the analysis. The basic characteristics between the reflow and no-reflow groups were similar, except for time-to-hospital admission, heart rate, plasma glucose, high-sensitivity C-reactive protein (hsCRP)/prealbumin (PAB), neutrophil count, intraaortic balloon pump, and aspiration thrombectomy. The multivariable analysis showed that hsCRP/PAB (OR = 1.003, 95% CI: 1.000–1.006, P=0.022), neutrophil count (OR = 1.085, 95% CI: 1.028–1.146, P=0.003), plasma glucose levels (OR = 1.086, 95% CI: 1.036–1.138, P=0.001), diabetes mellitus (OR = 0.596, 95% CI: 0.371–0.958, P=0.033), Killip classification >1 (OR = 2.002, 95% CI: 1.273–3.148, P=0.003), intraoperative intraaortic balloon pump (IABP) use (OR = 3.257, 95% CI: 1.954–5.428, P=0.001), and aspiration thrombectomy (OR = 3.412, 95% CI: 2.259–5.152, P=0.001) were independently associated with no-reflow.

Conclusion

hsCRP/PAB, neutrophil count, plasma glucose levels, diabetes mellitus, Killip classification, intraoperative IABP use, and aspiration thrombectomy were independent risk factors for no-reflow in patients with STEMI.

Effect of Diabetes Mellitus and Left Ventricular Perfusion on Frequency of Development of Heart Failure and/or All-cause Mortality Late After Acute Myocardial Infarction

Type 2 diabetes mellitus (DM) has a detrimental impact on cardiovascular outcomes, with implications for prognosis following ST elevation myocardial infarction (STEMI).The aim was to evaluate the impact of DM and myocardial perfusion on the long-term risk of heart failure (HF) and/or all-cause mortality following primary percutaneous coronary intervention (pPCI) for STEMI. A total of 406 STEMI patients (104 with DM) treated with pPCI were enrolled in this observational study. Myocardial perfusion was reassessed with the Quantitative Myocardial Blush Evaluator. Follow-up data on HF (ICD10 [International Statistical Classification of Diseases] codes I50.0 - I50.9) and all-cause mortality were obtained from the National Health Fund. During a 6-year follow-up, 36 (35%) patients with DM died compared with 45 (15%) patients without DM (p <0.001). Also, 24 (23%) patients with DM developed HF compared with 51 (17%) patients without DM (p = 0.20). Patients with DM and HF had the highest mortality rate (75%), and those with DM and a QuBE score below the median value (9.0 arb. units) had significantly higher risk of HF (hazard ratio [HR] =1.96, 95% CI 1.18 to 3.27, p = 0.0099) and the composite of HF and/or all-cause mortality (HR = 1.89, 95% CI 1.33 to 2.69, p = 0.0004). In conclusion DM (type 2) and diminished myocardial perfusion increase the risk of HF and/or all-cause mortality during a 6-year follow-up after pPCI for STEMI.

Increased Leukocyte Rolling in Newly Formed Mesenteric Vessels in the Rat during Peritoneal Dialysis

Objective

Long-term peritoneal dialysis (PD) is associated with the development of functional and structural alterations of the peritoneal membrane. The present study reports the effects of chronic exposure to PD fluid on mesenteric leukocyte–endothelium interactions, using intravital video microscopy.

Methods

Rats ( n = 7) received 10 mL lactate-buffered 3.86% glucose-containing PD fluid daily during a 5-week period via a subcutaneously implanted mini access port that was connected via a catheter to the peritoneal cavity. In a first control group ( n = 8), catheters were implanted but no fluid was instilled; a second control group ( n = 8) remained untreated. The number of rolling and adherent leukocytes as well as blood flow and other fluid dynamic variables were analyzed in mesenteric postcapillary (diameter 10 – 25 μ) and collecting (diameter 26 – 40 μ) venules. Neovascularization was semiquantitatively assessed after inspection of video images and by light and electron microscopy. Using FITC-labeled albumin, microvascular leakage was examined.

Results

Rats exposed to PD fluid showed a more than twofold increase in the number of rolling leukocytes ( p < 0.01); the number of adherent leukocytes was not changed. Furthermore, exposure to PD fluid induced severe neovascularization in rat mesentery. No microvascular leakage was observed in the various groups. The observed differences could not be explained by differences in systemic or local hemodynamic parameters or peripheral leukocyte counts, but is most likely associated with new vessel formation.

Conclusions

Exposure of rat peritoneal membrane to conventional PD fluid for 5 weeks affected local leukocyte–endothelium interactions. In addition, severe angiogenesis was induced, whereas microvascular permeability remained unaltered.

Association of postoperative glycemic control with outcomes after carotid procedures

Objective

There are limited data evaluating the impact of postoperative hyperglycemia in patients undergoing vascular procedures. This study evaluated the relationship between suboptimal glucose control and adverse outcomes after carotid artery stenting and carotid endarterectomy.

Methods

Patients admitted for elective carotid procedures were selected from the Cerner Health Facts® (2008–2015) database using ICD-9-CM diagnosis and procedure codes. We examined the relationship between patient characteristics, postoperative hyperglycemia (any value > 180 mg/dL), and complications with chi-square analysis. A multivariable model examined the association between patient characteristics, procedure type, and glucose control with infection, renal failure, stroke, respiratory and cardiac complications, and length of stay over 10 days.

Results

Of the 4287 patients admitted for an asymptomatic carotid procedure, 788 (18%) underwent carotid artery stenting and 3499 (82%) underwent carotid endarterectomy. Most patients (87%) had optimal postoperative glucose control (80–180 mg/dL); 13% had suboptimal glucose control. On average, patients with suboptimal glucose control experienced: higher stroke rates (6.2% vs. 2.7%; p <  0.001); more cardiac complications (5.1% vs. 2.0%; p <  0.001); longer hospital stays (3.1 vs. 1.8 days; p < .001); higher rates of post-procedure infection (4.0% vs. 1.8%; p = .001); and more complications than patients with optimal glucose control. Multivariable logistic regression demonstrated that patients with suboptimal glucose control had higher odds of having an infectious (pneumonia, cellulitis, surgical site, etc.) complication (OR 1.91, 95% CI 1.10–3.34), renal failure (OR 3.36, 95% CI 1.95–5.78), respiratory complications (OR 1.81, 95% CI 1.21–2.71), stroke (OR 1.82, 95% CI 1.15–2.88), or length of stay > 10 days (OR 4.07, 95% CI 2.02–8.20).

Conclusions

Suboptimal glucose control was associated with adverse events after carotid artery stenting and carotid endarterectomy, independent of a diabetes diagnosis. Several adverse outcomes were associated with hyperglycemia, including stroke. Given the singular role of carotid procedures in preventing stroke, we suggest that incorporating rigorous post-operative glucose control into best medical treatment of carotid disease should be considered as a standard practice.

Undiagnosed prediabetes status is associated with a reduced effectiveness of phosphodiesterase type 5 inhibitors in men with erectile dysfunction

The efficacy of phosphodiesterase type 5 inhibitors (PDE5i) in patients with erectile dysfunction (ED) and undiagnosed prediabetes (PreDM) has been scantly analysed. We aimed to assess rates of and predictors of response to oral treatment in a cohort of ED men naïve for PDE5i with either normo-glycaemia or PreDM or diabetes mellitus (DM). Complete data from 466 men were analysed. Comorbidities were scored with the Charlson Comorbidity Index (CCI). Patients completed the International Index of Erectile Function (IIEF) at baseline and after 3 months of PDE5i treatment. Treatment response was evaluated using the minimal clinically important difference (MCID) (mild: +2; moderate: +5; severe: +7 from baseline IIEF-EF). PreDM status was defined as for the American Diabetes Association (2015) criteria. Descriptive statistics and logistic regression models tested the association between clinical predictors and MCID response. Overall, 253 (56.7%), 105 (23.5%) and 88 (19.7%) patients had normo-glycaemia (=controls), PreDM and DM, respectively. Diabetic and PreDM men were older, had higher BMI, higher CCI scores and lower total testosterone (tT) (all p < 0.01) compared to controls. Median baseline IIEF-EF was lower both in PreDM (14.0 vs. 18.0; p < 0.05) and DM patients (10.0 vs. 18.0; p < 0.001) than in controls. IIEF-EF improved in all groups after treatment (all p < 0.001), but scores were higher in controls compared to both PreDM and DM men at 3-mos assessment (26.0 vs. 20.0 vs. 17.5, respectively; all p < 0.001). Controls more frequently achieved significant MCID than both PreDM and DM patients (65.3 vs. 22.9 vs. 11.8%, respectively; p < 0.01). Age (p < 0.001), baseline IIEF-EF (p < 0.001), and DM status (p = 0.02) were independently associated with MCID. In conclusion, patients with undiagnosed PreDM depicted lower rates of response to PDE5i than normoglycemic men. These findings suggest that even milder forms of glucose impairment are associated with a poorer PDE5i effectiveness in men with ED.

Ageing: Is there a role for arachidonic acid and other bioactive lipids? A review

Ageing is inevitable. Recent studies suggest that it could be delayed. Low-grade systemic inflammation is seen in type 2 diabetes mellitus, hypertension and endothelial dysfunction that are common with increasing age. In all these conditions, an alteration in arachidonic acid (AA) metabolism is seen in the form of increased formation of pro-inflammatory eicosanoids and decreased production of anti-inflammatory lipoxins, resolvins, protectins and maresins and decreased activity of desaturases. Calorie restriction, exercise and parabiosis delay age-related changes that could be related to enhanced proliferation of stem cells, decrease in inflammation and transfer of GDF-11 (growth differentiation factor-11) and other related molecules from the young to the old, increase in the formation of lipoxin A4, resolvins, protectins and maresins, hydrogen sulfide (H2S) and nitric oxide (NO); inhibition of ageing-related hypothalamic or brain IKK-β and NF-kB activation, decreased gonadotropin-releasing hormone (GnRH) release resulting in increased neurogenesis and consequent decelerated ageing. This suggests that hypothalamus participates in ageing process. N-acylethanolamines (NAEs) and lipid-derived signalling molecules can be tuned favorably under dietary restriction to extend lifespan and/or prevent advanced age associated diseases in an mTOR dependent pathway manner. Sulfur amino acid (SAA) restriction increased hydrogen sulfide (H2S) production and protected tissues from hypoxia and tissue damage. Anti-inflammatory metabolites formed from AA such as LXA4, resolvins, protectins and maresins enhance production of NO, CO, H2S; suppress NF-kB expression and alter mTOR expression and thus, may aid in delaying ageing process. Dietary restriction and exercise enhance AA metabolism to form LXA4, resolvins, protectins and maresins that have anti-inflammatory actions. AA and their metabolites also influence stem cell biology, enhance neurogenesis to improve memory and augment autophagy to prolong life span. Thus, AA and other PUFAs and their anti-inflammatory metabolites inhibit inflammation, augment stem cell proliferation, restore to normal lipid-derived signaling molecules and NO and H2S production, enhance autophagy and prolong life span.

Acute Insulin Resistance in Myocardial Ischemia: Causes and Consequences

Diabetes mellitus is associated with increased risk for cardiovascular mortality because of multiple pathophysiologic mechanisms. Acute stress-induced hyper-glycemia during acute myocardial infarction has gained much attention, as blood glucose levels seem to be an independent risk factor for acute myocardial infarction–related death. Clinical studies that identify stress-induced hyperglycemia as a risk factor are reviewed and its causes are discussed. They can be summarized as the consequence of acute insulin resistance, which in its turn is caused by stress hormones and by proinflammatory cytokines. Hyperglycemia causes the release of proinflammatory cytokines, the induction of reactive radicals, alterations in cardiovascular substrate metabolism, and propagation of coagulation and apoptosis. These all have harmful effects during and after acute myocardial infarction. Recommendations are for strict glycemic control in hyperglycemic patients with acute myocar-dial infarction, although the target glucose level is still a subject of debate.

Hyperglycemia and Outcome After Myocardial Infarction and Cardiac Surgery: So What?

Hyperglycemia is a frequent observation during acute illness such as myocardial infarction and after major surgery. The proportion of patients with hyperglycemia may be as high as 95% to 100% after cardiac surgery. This stress-induced hyperglycemia has a detrimental effect on outcome after myocardial infarction and cardiac surgery. Mortality may increase by a factor of 4, especially in non-diabetic patients. Control of hyperglycemia to normalize blood glucose is associated with a clear clinical benefit. This effect is most beneficial in nondiabetic patients with hyperglycemia. The exact target level of glycemia is still a matter of investigation, but normalization to values between 80 and 125 mg/dL is probably optimal.

Simple clinical risk score for no-reflow prediction in patients undergoing primary Percutaneous Coronary Intervention with acute STEMI

Objectives:

To identify the STEMI patients at high risk in terms of no-reflow during percutaneous coronary intervention (PCI) with a simple risk score system that can be used before reperfusion.

Methods:

Total 173 patients who had undergone primary or rescue percutaneous coronary intervention following the diagnosis of STEMI, were classified as “no-reflow” developers and “no-reflow” non-developers, during the procedure. The pre-procedural ECGs, laboratory parameters, demographic data, time for the treatment, and the treatment methods were evaluated with univariate analysis. The independent predictors were identified by multivariate logistic regression analysis among the no-reflow risk factors. Using the independent predictors, we developed a simple risk score system proportional to area under the ROC (AUROC) curves.

Results:

The independent predictors of “no-reflow” phenomenon were identified as follows: high values of blood glucose at reference; long symptom-onset-to-balloon-time; and low lymphocyte count. The incidence rates of “no-reflow” in patients with low (0-1), moderate (2-3) and high (4-6) risk factors were 13.3%, 40.0%, and 46.7%, respectively. The risk score system demonstrated a good risk prediction between patients with various risk levels of the development of “no-reflow” with a c-statistics of 0.734 (95% CI 0.654-0.814).

Conclusion:

The development of “no-reflow” which is an adverse event in STEMI treatment can be predicted efficiently by simple clinical risk scoring method.

1H-NMR-based metabolomic analysis of cerebrospinal fluid from adult bilateral moyamoya disease: comparison with unilateral moyamoya disease and atherosclerotic stenosis

Although metabolomics has been increasingly used to observe metabolic pattern and disease-specific metabolic markers, metabolite profiling for moyamoya disease (MMD) has not yet been done in adults. This study investigated cerebrospinal fluid (CSF) metabolites specific to bilateral MMD (B-MMD) and compared them to those of unilateral MMD (U-MMD) or atherosclerotic stenosis with hydrogen-1 nuclear magnetic resonance spectroscopy to identify metabolic biomarkers associated with MMD in adults.CSF samples of B-MMD (n = 29), U-MMD (n = 11), and atherosclerotic cerebrovascular disease (ACVD) (n = 8) were recruited. Principal component analysis, partial least square discriminant analysis, and orthogonal projections to latent structure discriminant analysis (OPLS-DA) were done for the comparisons. Diagnostic performance was acquired by prediction of 1 left-out sample from the distinction model constructed with the rest of the samples.B-MMD showed an increase in glutamine (P < 0.001) and taurine (P = 0.004), and a decrease in glucose (P < 0.001), citrate (P = 0.002), and myo-inositol (P = 0.006) than those in ACVD. U-MMD showed a higher level of glutamine (P = 0.005) and taurine (P = 0.034), and a lower level of glutamate (P < 0.004) than those in ACVD. No difference at the metabolite level was observed between B-MMD and U-MMD. Cross-validation with the OPLS-DA model showed a high accuracy for the prediction of MMD.The results of the study suggest that a metabolomics approach may be helpful in confirming MMD and providing a better understanding of MMD pathogenesis. Elevated glutamine in the CSF may be associated with MMD pathogenesis, which was different from ACVD.

Effect of diabetes on scintigraphic infarct size in STEMI patients undergoing primary angioplasty

BACKGROUND

It has been shown that among patients with ST-segment elevation myocardial infarction (STEMI), diabetes is associated with a significantly higher mortality, mainly because of impaired reperfusion. However, few data have been reported so far on infarct size as evaluated by well-refined techniques, such as nuclear imaging techniques. Therefore, the aim of the current study was to investigate the effect of diabetes in infarct size as evaluated by myocardial scintigraphy in a large cohort of STEMI patients undergoing primary PCI.

METHODS

We included 830 STEMI patients undergoing primary PCI. Infarct size was evaluated at 30 days by technetium-99 m-sestamibi. A logistic regression analysis was performed to determine the relation between diabetes and infarct size (as above the median) after correction for baseline confounding factors.

RESULTS

A total of 115 (13.8%) out of 830 patients suffered from diabetes. Diabetic patients were older (p < 0.001), with larger prevalence of female gender (p = 0.006) and hypertension (p = 0.001) but were less often smokers (p = 0.003). Diabetic patients had more often preprocedural thrombolysis in myocardial infarction grade 3 flow (p = 0.034) and less complete ST-segment resolution (p = 0.009). No difference was observed in scintigraphic infarct size between diabetes and control patients (p = 0.6)), which was confirmed at multivariate analysis after correction for baseline confounding factors (Adjusted OR [95% CI] = 0.87 [0.57-1.31, p = 0.51).

CONCLUSION

Our study showed that among STEMI patients undergoing primary angioplasty, diabetes did not affect infarct size as compared with non-diabetic patients.

Poly(ADP-ribose) polymerase-1 inhibition in brain endothelium protects the blood-brain barrier under physiologic and neuroinflammatory conditions

Blood-brain barrier (BBB) dysfunction seen in neuroinflammation contributes to mortality and morbidity in multiple sclerosis, encephalitis, traumatic brain injury, and stroke. Identification of molecular targets maintaining barrier function is of clinical relevance. We used a novel in vivo model of localized aseptic meningitis where tumor necrosis factor alpha (TNFα) was introduced intracerebrally and surveyed cerebral vascular changes and leukocyte-endothelium interactions by intravital videomicroscopy. Poly(ADP-ribose) polymerase-1 (PARP) inhibition significantly reduced leukocyte adhesion to and migration across brain endothelium in cortical microvessels. PARP inactivation diminished BBB permeability in an in vivo model of systemic inflammation. PARP suppression in primary human brain microvascular endothelial cells (BMVEC), an in vitro model of BBB, enhanced barrier integrity and augmented expression of tight junction proteins. PARP inhibition in BMVEC diminished human monocyte adhesion to TNFα-activated BMVEC (up to 65%) and migration (80-100%) across BBB models. PARP suppression decreased expression of adhesion molecules and decreased activity of GTPases (controlling BBB integrity and monocyte migration across the BBB). PARP inhibitors down-regulated expression of inflammatory genes and dampened secretion of pro-inflammatory factors increased by TNFα in BMVEC. These results point to PARP suppression as a novel approach to BBB protection in the setting of endothelial dysfunction caused by inflammation.

Association between hyperglycemia at admission and microvascular obstruction in patients with ST-segment elevation myocardial infarction

BACKGROUND

Blood glucose level at admission in ST-segment elevation myocardial infarction (STEMI) is a predictor of heart failure and mortality. A previous study showed the association between hyperglycemia and microvascular dysfunction using myocardial contrast echocardiography. Late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) can demonstrate microvascular obstruction (MVO) as the area with hypointense core within LGE. This study was performed to investigate the association between hyperglycemia at admission and MVO using CMR in patients with STEMI.

METHODS

Ninety-three patients with first STEMI who were treated by percutaneous coronary intervention (PCI) were included. CMR was performed within 7 days after PCI. Venous blood was collected routinely immediately after admission for plasma glucose determination before intravenous injection of some medications. Samples were analyzed in the hospital's central laboratory. We performed LGE-CMR to assess the presence of MVO.

RESULTS

MVO was found in 34 (37%) of all 93 patients; their glucose level at admission was significantly higher than that of patients who did not exhibit MVO [204 (153-267)mg/dl vs. 157 (127-200)mg/dl, p=0.002]. There were no differences in glycosylated hemoglobin and incidence of diabetes mellitus between the two groups. A multivariable logistic regression analysis showed that glucose level at admission was an independent predictor of MVO (odds ratio, 1.014; 95% confidence interval, 1.004 to 1.023; p=0.006). The glucose level at admission 190mg/dl was the best threshold value for identifying MVO. The occurrence of MVO was significantly higher in the patients with glucose level at admission ≧190mg/dl compared with the patients with glucose level <190mg/dl [18 (53%) vs. 16 (27%), p=0.023].

CONCLUSIONS

Hyperglycemia at admission in STEMI patients who were treated by PCI was associated with the presence of MVO assessed by LGE-CMR.

2013 Russell Ross memorial lecture in vascular biology: cellular and molecular mechanisms of diabetes mellitus-accelerated atherosclerosis

Adults with diabetes mellitus are much more likely to have cardiovascular disease than those without diabetes mellitus. Genetically engineered mouse models have started to provide important insight into the mechanisms whereby diabetes mellitus promotes atherosclerosis. Such models have demonstrated that diabetes mellitus promotes formation of atherosclerotic lesions, progression of lesions into advanced hemorrhaged lesions, and that it prevents lesion regression. The proatherosclerotic effects of diabetes mellitus are driven in part by the altered function of myeloid cells. The protein S100A9 and the receptor for advanced glycation end-products are important modulators of the effect of diabetes mellitus on myelopoiesis, which might promote monocyte accumulation in lesions. Furthermore, myeloid cell expression of the enzyme acyl-CoA synthetase 1 (ACSL1), which converts long-chain fatty acids into their acyl-CoA derivatives, has emerged as causal to diabetes mellitus-induced lesion initiation. The protective effects of myeloid ACSL1-deficiency in diabetic mice, but not in nondiabetic mice, indicate that myeloid cells are activated by diabetes mellitus through mechanisms that play minor roles in the absence of diabetes mellitus. The roles of reactive oxygen species and insulin resistance in diabetes mellitus-accelerated atherosclerosis are also discussed, primarily in relation to endothelial cells. Translational studies addressing whether the mechanisms identified in mouse models are equally important in humans with diabetes mellitus will be paramount.

Importance of perioperative glycemic control in general surgery: a report from the Surgical Care and Outcomes Assessment Program

OBJECTIVE

To determine the relationship of perioperative hyperglycemia and insulin administration on outcomes in elective colon/rectal and bariatric operations.

BACKGROUND

There is limited evidence to characterize the impact of perioperative hyperglycemia and insulin on adverse outcomes in patients, with and without diabetes, undergoing general surgical procedures.

METHODS

The Surgical Care and Outcomes Assessment Program is a Washington State quality improvement benchmarking-based initiative. We evaluated the relationship of perioperative hyperglycemia (>180 mg/dL) and insulin administration on mortality, reoperative interventions, and infections for patients undergoing elective colorectal and bariatric surgery at 47 participating hospitals between fourth quarter of 2005 and fourth quarter of 2010.

RESULTS

Of the 11,633 patients (55.4 ± 15.3 years; 65.7% women) with a serum glucose determination on the day of surgery, postoperative day 1, or postoperative day 2, 29.1% of patients were hyperglycemic. After controlling for clinical factors, those with hyperglycemia had a significantly increased risk of infection [odds ratio (OR) 2.0; 95% confidence interval (CI), 1.63-2.44], reoperative interventions (OR, 1.8; 95% CI, 1.41-2.3), and death (OR, 2.71; 95% CI, 1.72-4.28). Increased risk of poor outcomes was observed both for patients with and without diabetes. Those with hyperglycemia on the day of surgery who received insulin had no significant increase in infections (OR, 1.01; 95% CI, 0.72-1.42), reoperative interventions (OR, 1.29; 95% CI, 0.89-1.89), or deaths (OR, 1.21; 95% CI, 0.61-2.42). A dose-effect relationship was found between the effectiveness of insulin-related glucose control (worst 180-250 mg/dL, best <130 mg/dL) and adverse outcomes.

CONCLUSIONS

Perioperative hyperglycemia was associated with adverse outcomes in general surgery patients with and without diabetes. However, patients with hyperglycemia who received insulin were at no greater risk than those with normal blood glucoses. Perioperative glucose evaluation and insulin administration in patients with hyperglycemia are important quality targets.

Inhaled aerosolized insulin ameliorates hyperglycemia-induced inflammatory responses in the lungs in an experimental model of acute lung injury

Introduction

Previous studies have shown that patients with diabetes mellitus appear to have a lower prevalence of acute lung injury. We assumed that insulin prescribed to patients with diabetes has an anti-inflammatory property and pulmonary administration of insulin might exert beneficial effects much more than intravenous administration.

Methods

Twenty-eight mechanically ventilated rabbits underwent lung injury by saline lavage, and then the animals were allocated into a normoglycemia group (NG), a hyperglycemia group (HG), an HG treated with intravenous insulin (HG-VI) group or an HG treated with aerosolized insulin (HG-AI) group with continuous infusion of different fluid solutions and treatments: normal saline, 50% glucose, 50% glucose with intravenous insulin, or 50% glucose with inhaled aerosolized insulin, respectively. After four hours of treatment, the lungs and heart were excised en bloc, and then high-mobility group B1 concentration in bronchoalveolar lavage fluid, interleukin-8 and toll-like receptor 4 mRNA expression in bronchoalveolar lavage fluid cells, and lung myeloperoxidase activity were measured.

Results

Treatment with both aerosolized insulin and intravenous insulin attenuated toll-like receptor 4 mRNA expressions in the bronchoalveolar lavage fluid cells. Interleukin-8 and toll-like receptor 4 mRNA expression was significantly lower in the HG-AI group than in the HG-IV group. The lung myeloperoxidase activity in the normal healthy group showed significantly lower levels compared to the NG group but not different compared to those of the HG, HG-VI and HG-AI groups.

Conclusions

The results suggest that insulin attenuates inflammatory responses in the lungs augmented by hyperglycemia in acute lung injury and the insulin's efficacy may be better when administered by aerosol.

Impact of diabetes on long-term outcome after primary angioplasty: insights from the DESERT cooperation

OBJECTIVE

Diabetes has been shown to be associated with worse survival and repeat target vessel revascularization (TVR) after primary angioplasty. The aim of the current study was to evaluate the impact of diabetes on long-term outcome in patients undergoing primary angioplasty treated with bare metal stents (BMS) and drug-eluting stents (DES).

RESEARCH DESIGN AND METHODS

Our population is represented by 6,298 ST-segment elevation myocardial infarction (STEMI) patients undergoing primary angioplasty included in the DESERT database from 11 randomized trials comparing DES with BMS.

RESULTS

Diabetes was observed in 972 patients (15.4%) who were older (P < 0.001), more likely to be female (P < 0.001), with higher prevalence of hypertension (P < 0.001), hypercholesterolemia (P < 0.001), and longer ischemia time (P < 0.001), and without any difference in angiographic and procedural characteristics. At long-term follow-up (1,201 ± 441 days), diabetes was associated with higher rates of death (19.1% vs. 7.4%; P < 0.0001), reinfarction (10.4% vs. 7.5%; P < 0.001), stent thrombosis (7.6% vs. 4.8%; P = 0.002) with similar temporal distribution--acute, subacute, late, and very late--between diabetic and control patients, and TVR (18.6% vs. 15.1%; P = 0.006). These results were confirmed in patients receiving BMS or DES, except for TVR, there being no difference observed between diabetic and nondiabetic patients treated with DES. The impact of diabetes on outcome was confirmed after correction for baseline confounding factors (mortality, P < 0.001; repeat myocardial infarction, P = 0.006; stent thrombosis, P = 0.007; TVR, P = 0.027).

CONCLUSIONS

This study shows that among STEMI patients undergoing primary angioplasty, diabetes is associated with worse long-term mortality, reinfarction, and stent thrombosis in patients receiving DES and BMS. DES implantation, however, does mitigate the known deleterious effect of diabetes on TVR after BMS.

Relationship of thrombus characteristics to the incidence of angiographically visible distal embolization in patients with ST-segment elevation myocardial infarction treated with thrombus aspiration

OBJECTIVES

This study sought to investigate the association between pathological characteristics of aspirated intracoronary thrombi and the incidence of angiographically visible distal embolization (AVDE) during primary percutaneous coronary intervention (p-PCI) in patients with ST-segment elevation myocardial infarction (STEMI) treated with thrombus aspiration.

BACKGROUND

AVDE of atherosclerotic and thrombotic material has been shown to impair myocardial perfusion and contribute to poor clinical outcome in patients with STEMI. Recent studies have shown that thrombus composition and size are associated with the incidence of AVDE.

METHODS

Aspirated thrombi from 164 STEMI patients within 12 h of symptom onset were investigated immunohistochemically using antibodies against platelets, erythrocytes, and inflammatory cells.

RESULTS

The angiographic results showed that AVDE during p-PCI occurred in 22 (13.4%) patients. Pathological analysis revealed that thrombi from patients with AVDE had a greater erythrocyte-positive area (60 ± 15% vs. 43 ± 21%, p < 0.0005) and more myeloperoxidase-positive cells (943 ± 324 cells/mm(2) vs. 592 ± 419 cells/mm(2), p < 0.0005) than those from patients without AVDE. Thrombus size, quantified as the thrombus surface area, was positively correlated with the erythrocyte component (r = 0.362, p < 0.0001). Moreover, multivariate logistic analysis demonstrated that erythrocyte-positive area in the thrombi, glucose levels on admission, larger vessel diameter (≥ 3.5 mm), and pre-balloon dilation were independent predictors of the incidence of AVDE.

CONCLUSIONS

This study demonstrated that the erythrocyte-rich component of aspirated thrombi may be associated with the incidence of AVDE during p-PCI in patients with STEMI.

CXCL1-triggered interaction of LFA1 and ICAM1 control glucose-induced leukocyte recruitment during inflammation in vivo

It is well acknowledged that proinflammatory stimulation during acute hyperglycemia is able to aggravate inflammatory diseases. However, the mechanisms of proinflammatory effects of glucose are controversially discussed. We investigated leukocyte recruitment after intravenous injection of glucose in different inflammatory models using intravital microscopy. Flow chamber experiments, expression analysis, functional depletion, and knockout of key adhesion molecules gave mechanistic insight in involved pathways. We demonstrated that a single injection of glucose rapidly increased blood glucose levels in a dose-dependent manner. Notably, during tumor necrosis factor (TNF) α-induced inflammation leukocyte recruitment was not further enhanced by glucose administration, whereas glucose injection profoundly augmented leukocyte adhesion and transmigration into inflamed tissue in the trauma model, indicating that proinflammatory properties of glucose are stimulus dependent. Experiments with functional or genetic inhibition of the chemokine receptor CXCR2, intercellular adhesion molecule 1 (ICAM1), and lymphocyte function antigen 1 (LFA1) suggest that keratino-derived-chemokine CXCL1-triggered interactions of ICAM1 and LFA1 are crucially involved in the trauma model of inflammation. The lacking effect of glucose on β(2) integrin expression and on leukocyte adhesion in dynamic flow chamber experiments argues against leukocyte-driven underlying mechanisms and favours an endothelial pathway since endothelial ICAM1 expression was significantly upregulated in response to glucose.

[Post-resuscitation syndrome. Role of inflammation after cardiac arrest]

Cardiac arrest with subsequent cardiopulmonary resuscitation causes an ischemic reperfusion syndrome of the whole body resulting in localized damage of particularly sensitive organs, such as the brain and heart, together with systemic sequelae. The main factor is a generalized activation of inflammatory reactions resulting in symptoms similar in many aspects to those of sepsis. Systemic inflammation strengthens organ damage due to disorders in the macrocirculation and microcirculation due to metabolic imbalance as well as the effects of direct leukocyte transmitted tissue destruction. The current article gives an overview on the role of inflammation following cardiac arrest and presents in detail the underlying mechanisms, the clinical symptoms and possible therapeutic approaches.

Diabetic vascular disease and the potential role of macrophage glucose metabolism

Cardiovascular complications remain the leading cause of mortality in adult human subjects with diabetes. Hyperglycemia has long been hypothesized to explain some of the effects of diabetes on cardiovascular complications caused by atherosclerosis, but a clear causative role for hyperglycemia has not been established. Recent studies in animal models indicate that glucose may play a role in diabetes-accelerated atherosclerosis by promoting pro-inflammatory responses in myeloid cells, which are key cell types in atherosclerosis. For example, monocytes and macrophages often take on a more pro-inflammatory phenotype in the setting of diabetes. Moreover, in-vitro studies demonstrate a connection between pro-inflammatory molecules and glucose metabolism in macrophages and dendritic cells. This review concerns the role of glucose metabolism in inflammatory macrophages, and their potential role in diabetic vascular disease. Further in-vivo studies, focusing on myeloid-specific effects of glucose metabolism as it relates to atherosclerosis, are needed to increase our understanding of the relationship between diabetes, myeloid cells, and cardiovascular disease.

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.

Inflammatory and oxidative stress markers after intravenous insulin in percutaneous coronary intervention with stent in type 2 diabetes mellitus: a randomized controlled trial

CONTEXT/OBJECTIVE

The objective of the study was to evaluate the effects of normalizing glycemia through iv insulin per 24 h on markers of oxidative stress and inflammation in patients with diabetes submitted to percutaneous coronary intervention (PCI) with stent.

PATIENTS/METHODS

This was a prospective, open-label, randomized controlled trial, comparing continuous iv insulin per 24 h targeting glycemia less than 110 mg/dl iv insulin treatment (IIT; n = 35) to standard treatment (ST; n = 35, regular insulin if glycemia was greater than 200 mg/dl). Blood samples for glycemia, glycated hemoglobin, lipids, inflammatory markers [C-reactive protein (CRP), soluble CD40 ligand, IL-6, and endothelin 1 (ET-1)] and oxidative stress (total antioxidant status, carbonyl) were collected immediately after and 24 h after PCI.

RESULTS

Seventy patients were included. Mean age was 60.5 ± 10 yr, 60% were men, glycated hemoglobin was 8.1 ± 1.8 (IIT) vs. 7.6 ± 1.6% (ST) (P = 0.39). The intensive insulin group had lower glycemia (P = 0.006) and higher insulinemia (P < 0.001). Insulin did not change CRP [4.5 (2.1-11.7) vs. 6.8 (2.4-10.3), P = 0.35], soluble CD40 ligand [402 (191-843) vs. 610 (230-1200), P = 0.68], IL-6 [6.21 (3.1.-10.4) vs. 10.37 (5.9-15.3), P = 0.09], and ET-1 [1.02 (0.7-1.8) vs. 1.10 (0.7-1.9), P = 0.657]. CRP, IL-6, and ET-1 increased after PCI in both groups (P < 0.05). No change was observed on protein oxidation (carbonyl, P = 0.70; total antioxidant status, P = 0.33). There was a positive correlation between CRP and glycemia (r = 0.29, P = 0.002).

CONCLUSIONS

Continuous iv insulin for 24 h increased insulin levels and prevented hyperglycemia. Insulin infusion did not prevent the rise in inflammatory and oxidative stress markers, and no differences were observed between IIT and ST after PCI with a stent.

Protein kinase C upregulates intercellular adhesion molecule-1 and leukocyte-endothelium interactions in hyperglycemia via activation of endothelial expressed calpain

OBJECTIVE

We tested the hypothesis of a role for the calcium-dependent protease calpain in the endothelial dysfunction induced by hyperglycemic activation of protein kinase C (PKC).

METHODS AND RESULTS

Chronic hyperglycemia with insulin deficiency (type 1 diabetes) was induced in rats by streptozotocin. Total PKC and calpain activities, along with activity and expression level of the 2 endothelial-expressed calpains isoforms, μ- and m-calpain, were measured in vascular tissue homogenates by enzymatic assays and Western blot analysis, respectively. Intravital microscopy was used to measure and correlate leukocyte-endothelium interactions with calpain activity in the microcirculation. Expression levels and endothelial localization of the inflammatory adhesion molecule intercellular adhesion molecule-1 were studied by Western blot analysis and immunofluorescence, respectively. The mechanistic role of hyperglycemia alone in the process of PKC-induced calpain activation and actions was also investigated. We found that in the type 1 diabetic vasculature, PKC selectively upregulates the activity of the μ-calpain isoform. Mechanistic studies confirmed a role for hyperglycemia and PKCβ in this process. The functional implications of PKC-induced calpain activation were upregulation of endothelial expressed intercellular adhesion molecule-1 and leukocyte-endothelium interactions.

CONCLUSIONS

Our results uncover the role of μ-calpain in the endothelial dysfunction of PKC. Calpain may represent a novel molecular target for the treatment of PKC-associated diabetic vascular disease.

Increase in GLUT1 in smooth muscle alters vascular contractility and increases inflammation in response to vascular injury

OBJECTIVE

The goal of this study was to test the contributing role of increasing glucose uptake in vascular smooth muscle cells (VSMCs) in vascular complications and disease.

METHODS AND RESULTS

A murine genetic model was established in which glucose trasporter 1 (GLUT1), the non-insulin-dependent glucose transporter protein, was overexpressed in smooth muscle using the sm22α promoter. Overexpression of GLUT1 in smooth muscle led to significant increases in glucose uptake (n=3, P<0.0001) as measured using radiolabeled 2-deoxyglucose. Fasting blood glucose, insulin, and nonesterified fatty acids were unchanged. Contractility in aortic ring segments was decreased in sm22α-GLUT1 mice (n=10, P<0.04). In response to vascular injury, sm22α-GLUT1 mice exhibited a proinflammatory phenotype, including a significant increase in the percentage of neutrophils in the lesion (n=4, P<0.04) and an increase in monocyte chemoattractant protein-1 (MCP-1) immunofluorescence. Circulating haptoglobin and glutathione/total glutathione were significantly higher in the sm22α-GLUT1 mice postinjury compared with controls (n=4, P<0.05), suggesting increased flux through the pentose phosphate pathway. sm22α-GLUT1 mice exhibited significant medial hypertrophy following injury that was associated with a significant increase in the percentage of VSMCs in the media staining positive for nuclear phosphoSMAD2/3 (n=4, P<0.003).

CONCLUSIONS

In summary, these findings suggest that increased glucose uptake in VSMCs impairs vascular contractility and accelerates a proinflammatory, neutrophil-rich lesion in response to injury, as well as medial hypertrophy, which is associated with enhanced transforming growth factor-β activity.

Peritoneal dialysis fluid bioincompatibility and new vessel formation promote leukocyte-endothelium interactions in a chronic rat model for peritoneal dialysis

Peritoneal dialysis (PD)-induced peritonitis leads to dysfunction of the peritoneal membrane. During peritonitis, neutrophils are recruited to the inflammation site by rolling along the endothelium, adhesion, and transmigration through vessel walls. In a rat PD-model, long-term effects of PD-fluids (PDF) on leukocyte-endothelium interactions and neutrophil migration were studied under baseline and inflammatory conditions. Rats received daily conventional-lactate-buffered PDF (Dianeal), bicarbonate/lactate-buffered PDF (Physioneal) or bicarbonate/lactate buffer (Buffer) during five weeks. Untreated rats served as control. Baseline leukocyte rolling and N-formylmethionyl-leucyl-phenylalanine (fMLP) induced levels of transmigration in the mesentery were evaluated and quantified by intra-vital videomicroscopy and immunohistochemistry. Baseline leukocyte rolling was unaffected by buffer treatment, approximately 2-fold increased after Physioneal and 4-7-fold after Dianeal treatment. After starting fMLP superfusion, transmigrated leukocytes appeared outside the venules firstly after Dianeal treatment (15 minutes), thereafter in Physioneal and Buffer groups (20-22 minutes), and finally in control rats (>25 minutes). Newly formed vessels and total number of transmigrated neutrophils were highest in Dianeal-treated animals, followed by Physioneal and Buffer, and lowest in control rats and correlated for all groups to baseline leukocyte rolling (r = 0.78, P < 0.003). This study indicates that the start of inflammatory neutrophil transmigration is related to PDF bio(in)compatibility, whereas over time neutrophil transmigration is determined by the degree of neo-angiogenesis.

Microvascular responses to cardiovascular risk factors

Hypertension, hypercholesterolemia, diabetes, and obesity are among a growing list of conditions that have been designated as major risk factors for cardiovascular disease (CVD). While CVD risk factors are well known to enhance the development of atherosclerotic lesions in large arteries, there is also evidence that the structure and function of microscopic blood vessels can be profoundly altered by these conditions. The diverse responses of the microvasculature to CVD risk factors include oxidative stress, enhanced leukocyte- and platelet-endothelial cell adhesion, impaired endothelial barrier function, altered capillary proliferation, enhanced thrombosis, and vasomotor dysfunction. Emerging evidence indicates that a low-grade systemic inflammatory response that results from risk factor-induced cell activation and cell-cell interactions may underlie the phenotypic changes induced by risk factor exposure. A consequence of the altered microvascular phenotype and systemic inflammatory response is an enhanced vulnerability of tissues to the deleterious effects of secondary oxidative and inflammatory stresses, such as ischemia and reperfusion. Future efforts to develop therapies that prevent the harmful effects of risk factor-induced inflammation should focus on the microcirculation.

Variation in characteristics of islets of Langerhans in insulin-resistant, diabetic and non-diabetic-rat strains

Assessment of the histopathological and plasma biochemical characteristics of diabetic and non-diabetic rat strains [Han and AP Wistar, lean and obese Zucker Fatty (ZF), and lean and obese Zucker Diabetic Fatty (ZDF) rats] was performed at 6 or 14 weeks of age. Wistar and lean ZF and ZDF rats showed no or minimal islet pathology or plasma biochemical alterations at both timepoints. Obese ZFs were euglycaemic at both timepoints and mildly and severely hyperinsulinaemic at 6 and 14 weeks respectively. Islet morphology was normal at 6 weeks but at 14 weeks, islet hyperplasia was present with a minority showing degenerative changes namely, beta-cell vacuolation, vascular congestion and haemorrhage with minimal mononuclear cell and T lymphocytic infiltration. Obese ZDFs were euglycaemic and moderately hyperinsulinaemic at 6 weeks and severely hyperglycaemic with minor hypoinsulinaemia at 14 weeks. Obese ZDFs at 6 weeks showed mainly normal islets with some displaying degeneration (ranging from beta-cell vacuolation alone to the features described above). At 14 weeks, islet degeneration was more severe and widespread: beta-cell death was present in numerous islets at low level. Islet beta-cell numbers were reduced or absent (with associated reduction in insulin immunostaining) within the islets that now consisted predominantly of fibroblasts, collagen and mononuclear cells. Fibroproliferation consisting of smooth muscle actin-alpha-positive tissue was associated with mononuclear cell infiltration. Some fibrous scars were visible indicative of lost islets. Islet degeneration in obese ZF and ZDF rats was not accompanied by a reduction in beta-cell proliferation or in compensatory proliferation of beta-cell neogenic clusters. In the light of recent reports of adaptive and inflammation-mediated degenerative changes in human non-insulin dependent diabetes mellitus (NIDDM) islets, the hypertrophy/hyperplasia of beta-cells and islet degeneration involving infiltration by monocyte/macrophages in obese ZF and obese ZDF rats respectively offers substantial potential for elucidation of the processes involved.

Loss of insulin signaling in vascular endothelial cells accelerates atherosclerosis in apolipoprotein E null mice

To determine whether insulin action on endothelial cells promotes or protects against atherosclerosis, we generated apolipoprotein E null mice in which the insulin receptor gene was intact or conditionally deleted in vascular endothelial cells. Insulin sensitivity, glucose tolerance, plasma lipids, and blood pressure were not different between the two groups, but atherosclerotic lesion size was more than 2-fold higher in mice lacking endothelial insulin signaling. Endothelium-dependent vasodilation was impaired and endothelial cell VCAM-1 expression was increased in these animals. Adhesion of mononuclear cells to endothelium in vivo was increased 4-fold compared with controls but reduced to below control values by a VCAM-1-blocking antibody. These results provide definitive evidence that loss of insulin signaling in endothelium, in the absence of competing systemic risk factors, accelerates atherosclerosis. Therefore, improving insulin sensitivity in the endothelium of patients with insulin resistance or type 2 diabetes may prevent cardiovascular complications.

Inflammation determines the pro-adhesive properties of high extracellular d-glucose in human endothelial cells in vitro and rat microvessels in vivo

Background

Hyperglycemia is acknowledged as an independent risk factor for developing diabetes-associated atherosclerosis. At present, most therapeutic approaches are targeted at a tight glycemic control in diabetic patients, although this fails to prevent macrovascular complications of the disease. Indeed, it remains highly controversial whether or not the mere elevation of extracellular D-glucose can directly promote vascular inflammation, which favors early pro-atherosclerotic events.

Methods and Findings

In the present work, increasing extracellular D-glucose from 5.5 to 22 mmol/L was neither sufficient to induce intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression, analyzed by flow cytometry, nor to promote leukocyte adhesion to human umbilical vein endothelial cells (HUVEC) in vitro, measured by flow chamber assays. Interestingly, the elevation of D-glucose levels potentiated ICAM-1 and VCAM-1 expression and leukocyte adhesion induced by a pro-inflammatory stimulus, such as interleukin (IL)-1β (5 ng/mL). In HUVEC, high D-glucose augmented the activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and nuclear transcription factor-κB (NF-κB) elicited by IL-1β, measured by Western blot and electromobility shift assay (EMSA), respectively, but had no effect by itself. Both ERK 1/2 and NF-κB were necessary for VCAM-1 expression, but not for ICAM-1 expression. In vivo, leukocyte trafficking was evaluated in the rat mesenteric microcirculation by intravital microscopy. In accordance with the in vitro data, the acute intraperitoneal injection of D-glucose increased leukocyte rolling flux, adhesion and migration, but only when IL-1β was co-administered.

Conclusions

These results indicate that the elevation of extracellular D-glucose levels is not sufficient to promote vascular inflammation, and they highlight the pivotal role of a pro-inflammatory environment in diabetes, as a critical factor conditioning the early pro-atherosclerotic actions of hyperglycemia.

Insulin-treated diabetes is not associated with increased mortality in critically ill patients

Introduction

This was a planned substudy from the European observational Sepsis Occurrence in Acutely ill Patients (SOAP) study to investigate the possible impact of insulin-treated diabetes on morbidity and mortality in ICU patients.

Methods

The SOAP study was a cohort, multicenter, observational study which included data from all adult patients admitted to one of 198 participating ICUs from 24 European countries during the study period. For this substudy, patients were classified according to whether or not they had a known diagnosis of insulin-treated diabetes mellitus. Outcome measures included the degree of organ dysfunction/failure as assessed by the sequential organ failure assessment (SOFA) score, the occurrence of sepsis syndromes and organ failure in the ICU, hospital and ICU length of stay, and all cause hospital and ICU mortality.

Results

Of the 3147 patients included in the SOAP study, 226 (7.2%) had previously diagnosed insulin-treated diabetes mellitus. On admission, patients with insulin-treated diabetes were older, sicker, as reflected by higher simplified acute physiology system II (SAPS II) and SOFA scores, and more likely to be receiving hemodialysis than the other patients. During the ICU stay, more patients with insulin-treated diabetes required renal replacement therapy (hemodialysis or hemofiltration) than other patients. There were no significant differences in ICU or hospital lengths of stay or in ICU or hospital mortality between patients with or without insulin-treated diabetes. Using a Cox proportional hazards regression analysis with hospital mortality censored at 28-days as the dependent factor, insulin-treated diabetes was not an independent predictor of mortality.

Conclusions

Even though patients with a history of insulin-treated diabetes are more severely ill and more likely to have renal failure, insulin-treated diabetes is not associated with increased mortality in ICU patients.

Similar effects of resistin and high glucose on P-selectin and fractalkine expression and monocyte adhesion in human endothelial cells

Resistin and high glucose (HG) are concomitantly present at elevated concentration in diabetic's plasma; both are pro-inflammatory agents acting on vascular cells by mechanisms that are not fully understood. We questioned whether resistin and HG affect the expression of major adhesion molecules, P-selectin and fractalkine in human endothelial cells (HEC). The results showed that in HEC (i) resistin increased P-selectin expression; (ii) HG up-regulated Fk expression; (iii) P-selectin and fractalkine were functional increasing monocyte adhesion to activated cells. Co-stimulation with resistin and HG increased P-selectin and fractalkine mRNA and protein and induced monocyte adhesion, generated an increase in NADPH oxidase activity and of the intracellular reactive oxygen species and activated the NF-kB and AP-1 transcription factors at similar values as those of each activator. In conclusion in HEC, resistin and HG induce the up-regulation of P-selectin and fractalkine and the ensuing increased monocyte adhesion by a mechanism involving oxidative stress and NF-kB and AP-1 activation.

The mannose-binding lectin pathway is a significant contributor to reperfusion injury in the type 2 diabetic heart

The severity of ischaemic heart disease is markedly enhanced in type 2 diabetes. We recently reported that complement activation exacerbates I/R injury in the type 2 diabetic heart. The purpose of this study was to isolate and examine MBL pathway activation following I/R injury in the diabetic heart. ZLC and ZDF rats underwent 30 minutes of left coronary artery occlusion followed by 120 minutes of reperfusion. Two different groups of ZDF rats were treated with either FUT-175, a broad complement inhibitor, or P2D5, a monoclonal antibody raised against rat MBL-A. ZDF rats treated with FUT175 and P2D5 had significantly decreased myocardial infarct size, C3 deposition and neutrophil accumulation compared with untreated ZDF controls. Taken together, these findings indicate that the MBL pathway plays a key role in the severity of complement-mediated I/R injury in the type 2 diabetic heart.

Acute effects of peritoneal dialysis solutions in the mesenteric microcirculation

Long-term peritoneal dialysis induces morphological changes that may lead to gradual functional impairment of the peritoneal membrane. These changes are characterized by progressive reduction in solute transport or ultrafiltration failure. The mechanism of the peritoneal response to dialysis fluids has not yet been fully elucidated. We used video-microscopy for in vivo evaluation of microhemodynamics and peritoneal microvascular inflammatory response, after a single intraperitoneal exposure of rats to commercial PD fluids: (1) glucose 1.5 % PD solution; (2) lactate buffered glucose 4.25% PD solution; (3) Icodextrin 7%; (4) bicarbonate buffered glucose 3.86% PD fluid; and 5) Hanks solution. Sham-control groups were not injected. A 5-h exposure of the peritoneal membrane to glucose 1.5% PD solution or to Hanks solution did not induce a significant change in leukocyte rolling and adhesion. In contrast, PD solutions containing glucose 4.25% or Icodextrin 7.5% caused a significant 2-3-fold increase in leukocyte rolling (P < 0.001) and adhesion (P < 0.001) and a significant increase in venular blood flow velocity (P < 0.01) and shear rates (P < 0.05 for glucose 4.25%, and P < 0.01 for Icodextrin). Exposure to glucose 3.86% bicarbonate buffered (Physioneal) solution was associated with the lowest values of leukocyte rolling and adhesion among the PD solutions and with extremely higher venular flow velocities and shear rates. A single exposure to conventional PD solutions with a high concentration of glucose (4.25%) or polyglucose (Icodextrin 7.5%) induces changes consistent with an early peritoneal inflammatory response that may be attenuated by the use of bicarbonate-based fluids.

Diabetes and atherosclerosis: is there a role for hyperglycemia?

Atherosclerosis is accelerated in both type 1 and type 2 diabetes. The hallmark of diabetes is the presence of hyperglycemia. In this article, we review the role of glucose in the pathogenesis of atherosclerosis. Evidence obtained from epidemiological, in vitro, and animal studies will be reviewed in an attempt to understand the complex relationship between hyperglycemia and cardiovascular risk that is emerging from clinical trials.

Endothelial dysfunction in mice with streptozotocin-induced type 1 diabetes is opposed by compensatory overexpression of cyclooxygenase-2 in the vasculature

Cardiovascular complications of diabetes result from endothelial dysfunction secondary to persistent hyperglycemia. We investigated potential compensatory mechanisms in the vasculature that oppose endothelial dysfunction in diabetes. BALB/c mice were treated with streptozotocin (STZ) to induce type 1 diabetes (T1D). In mesenteric vascular beds (MVBs), isolated ex vivo from mice treated with STZ for 1 wk, dose-dependent vasorelaxation to acetylcholine (ACh) or sodium nitroprusside was comparable with that in age-matched control mice (CTRL). By contrast, MVBs from mice treated with STZ for 8 wk had severely impaired vasodilator responses to ACh consistent with endothelial dysfunction. Pretreatment of MVBs from CTRL mice with nitric oxide synthase inhibitor nearly abolished vasodilation to ACh. In MVB from 1-wk STZ-treated mice, vasodilation to ACh was only partially impaired by L-N(omega)-arginine methyl ester. Thus, vasculature of mice with T1D may have compensatory nitric oxide-independent mechanisms to augment vasodilation to ACh and oppose endothelial dysfunction. Indeed, pretreatment of MVBs isolated from 1-wk STZ-treated mice with NS-398 [selective cyclooxygenase (COX)-2 inhibitor] unmasked endothelial dysfunction not evident in CTRL mice pretreated without or with NS-398. Expression of COX-2 in MVBs, aortic endothelial cells, and aortic vascular smooth muscle cells from STZ-treated mice was significantly increased (vs. CTRL). Moreover, concentrations of the COX-2-dependent vasodilator 6-keto-prostaglandin F-1alpha was elevated in conditioned media from aorta of STZ-treated mice. We conclude that endothelial dysfunction in a mouse model of T1D is opposed by compensatory up-regulation of COX-2 expression and activity in the vasculature that may be relevant to developing novel therapeutic strategies for diabetes and its cardiovascular complications.