The interleukin 6 c.-174 CC genotype is a predictor for new cardiovascular events in patients with coronary heart disease within three years follow-up

The main aim of this study was to evaluate putative associations between the interleukin (IL)-6 c.-174G>C polymorphism (rs 1800795) and the cardiovascular outcome (combined endpoint: myocardial infarction, stroke/TIA, cardiac death, death according to stroke) among patients with coronary heart disease (CHD) within three years follow-up. Overall 942 in-patients with CHD were included. The drop-out rate was 4.9%. The IL-6 polymorphism was determined with PCR-SSP. Kaplan-Meier plots with Log Rank test and Cox regression were used as statistically procedures. The IL-6 CC genotype was associated with a higher incidence of the combined endpoint (25.0% versus 13.5%, p<0.001) and an increased Hazard Ratio (HR 2.165, 95% CI 1.516-3.092, p<0.001) adjusted for established cofactors for CHD. This result suggests that the IL-6 -174 polymorphism is a putative independent risk indicator for new cardiovascular events among patients with CHD.

Glycation of the high affinity NGF-receptor and RAGE leads to reduced ligand affinity

AGEs are posttranslational modifications generated by irreversible non-enzymatic crosslinking reactions between sugars and proteins - a reaction referred to as glycation. Glycation, a feature of ageing, can lead to non-degradable and less functional proteins and enzymes and can additionally induce inflammation and further pathophysiological processes such as neurodegeneration. In this study we investigated the influence of glycation on the high affinity NGF-receptor TrkA and the AGE-receptor RAGE. We quantified the binding affinity of the TrkA-receptor and RAGE to their ligands by surface plasmon resonance (SPR) and compared these to the binding affinity after glycation. At the same time, we established a glycation procedure using SPR. We found that glycation of TrkA reduced the affinity to NGF by a factor of three, which could be shown to lead to a reduction of NGF-dependent neurite outgrowth in PC12 cells. Glycation of RAGE reduced binding affinity of AGEs by 10-fold.

Protein glycation - Between tissue aging and protection

Non-enzymatic formation of advanced glycation endproducts (AGEs) is associated with degenerative diseases. Chronic accumulation of AGEs with age in tissues especially in the extracellular matrix is well known and at least in part responsible for e.g., collagen crosslinking, tissue stiffening and thus induction of high blood pressure or diastolic heart failure. Binding of soluble AGEs to the receptor for AGEs, RAGE, induces an inflammatory response whereas the soluble form of RAGE (sRAGE) can inhibit inflammatory tissue injury like arteriosclerosis in mouse models. However, there are a number of indications that AGEs have protective effects as well. AGEs may inhibit lung tumor growth, glyoxal induced AGE modification of human heart muscle can reduce an ischemia reperfusion injury and AGEs from nutrition can reduce ROS induced cell damage.

CONCLUSIONS

In summary, this indicates that protein glycation behaves like a double-edged sword. It induces tissue aging and degenerative diseases on the one hand, on the other hand, may also have protective effects, indicating a hormetic response.

Glycation of extracellular matrix proteins impairs migration of immune cells

The immune response during aging and diabetes is disturbed and may be due to the altered migration of immune cells in an aged tissue. Our study should prove the hypothesis that age and diabetes-related advanced glycation end products (AGEs) have an impact on the migration and adhesion of human T-cells. To achieve our purpose, we used in vitro AGE-modified proteins (soluble albumin and fibronectin [FN]), as well as human collagen obtained from bypass graft. A Boyden chamber was used to study cell migration. Migrated Jurkat T-cells were analyzed by flow cytometry and cell adhesion by crystal violet staining. Actin polymerization was determined by phalloidin-Alexa-fluor 488-labeled antibody and fluorescence microscopy. We found that significantly fewer cells (50%, p = 0.003) migrated through methylglyoxal modified FN. The attachment to FN in the presence of AGE-bovine serum albumin (BSA) was also reduced (p < 0.05). In ex vivo experiments, isolated collagen from human vein graft material negatively affected the migration of the cells depending on the grade of AGE modification of the collagen. Collagen with a low AGE level reduced the cell migration by 30%, and collagen with a high AGE level by 60%. Interaction of the cells with an AGE-modified matrix, but not with soluble AGEs like BSA-AGE per se, was responsible for a disturbed migration. The reduced migration was accompanied by an impaired actin polymerization. We conclude that AGEs-modified matrix protein inhibits cell migration and adhesion of Jurkat T-cells.

[Sexually transmitted infections as a cause for solid rectal pseudo tumors]

Two cases of symptomatic proctitis with rectal tumors suspicious for malignancy are presented. A florid regenerative proctitis was shown in the histological examination. In both cases a sexually transmitted infection (STI) was causing the symptoms. In rare cases STIs present as pseudo tumors mimicking malignancy in clinical examination and endoscopic/radiological analysis. A close collaboration between gastroenterologist and pathologist is necessary for a correct diagnosis and to prevent unnecessary surgical treatment.

Advanced glycation endproducts interfere with adhesion and neurite outgrowth

Advanced glycation endproducts (AGEs) represent a non-enzymatic posttranslational protein modification. AGEs are generated by a series of chemical reactions of free reducing monosaccharides, such as glucose, fructose or metabolites of the monosaccharide metabolism with amino groups of proteins. After oxidation, dehydration and condensation, stable AGE-modifications are formed. AGE-modified proteins accumulate in all cells and tissues as a normal feature of ageing and correlate with the glucose concentration in the blood. AGEs are increased in diabetic patients and play a significant role in the pathogenesis of most age-related neural disorders, such as Alzheimer’s disease. We examined the role of AGEs on neurite outgrowth of PC12 cells. We induced the formation of AGEs using the reactive carbonyl compound methylglyoxal (MGO) as a physiological metabolite of glucose. We found that AGE-modification of laminin or collagen interfered with adhesion but not with neurite outgrowth of PC12 cells. Furthermore, the AGE-modification of PC12 cell proteins reduced NGF-induced neurite outgrowth. In conclusion, our data show that AGEs negatively influence neural plasticity.

The skin autofluorescence reflects the posttranslational glycation grade of the matrix protein collagen

Advanced glycation end products (AGEs) seem to be involved in ageing as well as in the development of cardiovascular diseases. Accumulation of AGEs contribute to tissue stiffness and organ dysfunction by crosslinking extracellular matrix proteins like collagen. We aimed to assess whether AGE-modified cardiac tissue collagen and AGE related skin autofluorescence may reflect the cardiac function and have a prognostic value for the outcome of coronary artery bypass surgery patients. Therefore, AGE-modifications in collagen from 72 male patients undergoing isolated coronary artery bypass graft (CABG) surgery were analyzed. Collagen fractions were isolated from the right atrial auricle and the residual bypass graft material (saphenous vein) of these patients and quantified by 4-hydroxyproline assay. AGE modifications were determined by the AGE intrinsic fluorescence (excitation 360nm/emission 440nm). The skin autofluorescence (sAF) as a non-invasive parameter was measured using the AGE reader. The non-extractable collagen contained the highest amounts of AGEs and positively correlates with the patients age (p=0.0001), blood glucose level (p=0.002), HbA1c level (p=0.01) and sAF (p=0.008). The right atrial auricle collagen showed significantly more modifications compared to vein graft material of the same patient (p=0,001). Skin autofluorescence positively correlates with AGE content in cardiac tissue (p=0.01) and therefore could be used as a predictor of tissue stiffness in patients with coronary heart disease.

Carotid to femoral pulse wave velocity reflects the extent of coronary artery disease

Arterial stiffness is a well-established risk factor for cardiovascular disease and mortality. Carotid to femoral pulse wave velocity (cfPWV) as a measure of arterial stiffness was obtained in 155 (47 women; 67.2±9.1 years, range 44-87 years) patients with detected coronary artery disease (CAD) scheduled for coronary artery bypass surgery. The authors set out to analyze how cfPWV in CAD patients correlates with reference values for healthy, normotensive volunteers and whether cfPWV values reflect the extent of CAD. cfPWV was measured with an oscillometric device. Mean cfPWV value of CAD patients was 9.3±1.9 m/s vs 7.7±1.1 m/s in healthy volunteers (P<.0001). In a multiple regression model, age (P<.0001), sex (P=.006), systolic arterial pressure (P=.04), mean arterial pressure (P=.04), and severity of CAD (P<.001) emerged as independent predictive markers for cfPWV in CAD patients. This study established reference values for cfPWV in CAD patients measured with an oscillometric device and confirmed the strong association between arterial stiffness and severity of CAD.

RAGE influences the development of aortic valve stenosis in mice on a high fat diet

Advanced glycation end product (AGE) accumulations as well as a high fat diet are associated with cardiovascular diseases. AGEs are recognized by several receptor molecules of which the receptor of AGEs (RAGE) is currently the most intensively studied. Activation of RAGE causes an unfavorable pro-inflammatory state. The hypothesis of this study was that metabolic stress due to a high fat diet results in the development of aortic valve stenosis and that knockout of RAGE should be protective. Six week old male C57BL/6N and C57BL/6N RAGE-/- mice (n=28) were randomly assigned to 4 groups and fed with normal or high fat diet for 32weeks. Weight gain was determined weekly. At the start of the experiment and after 2, 4 and 7months, echocardiographic assessments of the aortic valve were made. At the end of the experiment, plasma lipid levels and histological changes of the valves were determined. The high fat diet resulted in accelerated weight gain. However, after 7month, only C57BL/6 mice developed increased trans-aortic-valve velocities, leaflet thickness and reduced valve area index (p<0.0001). Immunohistochemistry of the aortic valves revealed in C57BL/6N mice on a high fat diet more calcification, AGE accumulation and RAGE expression when compared to normal fed control. Hearts and aortic valves of RAGE-/- mice showed less morphometric changes, calcification and AGE accumulation. After 7months of high fat feeding C57BL/6 mice (p<0.0001) as well as RAGE-/- mice (p=0.007) had significantly increased cholesterol levels compared to normal fed control, however RAGE-/- mice were probably protected due to a better HDL/LDL ratio when compared to wild type animals (p=0.003). These data suggest that AGEs and RAGE are involved in the development of obesity, hypercholesterolemia and aortic valve changes due to metabolic stress from high fat intake.

Inter-hospital transfer of ECMO-assisted patients with a portable miniaturized ECMO device: 4 years of experience

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) in patients with severe pulmonary failure is able to keep patients alive until organ regeneration, until shunting out for further diagnostic and therapeutic options or until transportation to specialized centers. Nonetheless, extracorporeal techniques require a high degree of expertise, so that a confinement to specialized centers is meaningful. Following from this requirement, the need for inter-hospital transfer of patients with severely compromised pulmonary function is rising.

METHODS

We report about our experience with a portable ECMO system during inter-hospital air or ground transfer of patients with cardiopulmonary failure.

RESULTS

The portable ECMO system was used for transportation to the center and in-hospital treatment in 36 patients with an average age of 53 years suffering from respiratory failure. Accordingly, the ECMO system was implanted as a veno-venous extracorporeal system. Pre-ECMO ventilation time was 5.2 (2-9) days. Twelve patients were transported to our institution by ground and 24 patients by air ambulance over a median distance of 46 km. With the assistance of the ECMO device, prompt stabilization of cardiopulmonary function could be achieved in all patients without any technical complications. Post-ECMO ventilation was 9.8 days. Weaning from the ECMO system was successful in 61% of all patients after a median device working period of 12.7 days; median ICU stay was 34 days and a survival rate of 64% of patients was achieved. Technical (8%) and device-associated bleeding (11%)/thromboembolic (8%) complication rates showed very acceptable levels.

CONCLUSION

Our experience demonstrates that miniaturized, portable ECMO therapy allows location-independent, out-of-center stabilization of pulmonary compromised patients with consecutive inter-hospital transfer and further in-house treatment, so that sophisticated ECMO therapy can be offered to every patient, even in hospitals with primary healthcare.

First experiences with a combined usage of veno-arterial and veno-venous ECMO in therapy-refractory cardiogenic shock patients with cerebral hypoxemia

The use of extracorporeal membrane oxygenation (ECMO) is becoming a popular tool in the treatment of cardiogenic shock. We present two case reports where classical veno-arterial peripherally cannulated ECMO therapy proved insufficient with profuse cerebral hypoxemia. After augmenting the setting into veno-veno-arterial ECMO, we achieved a remarkable improvement of all oxygenation parameters. The simultaneous use of veno-venous and veno-arterial ECMO might display as a novel strategy to counteract the coronary and cerebral hypoxemia in veno-arterial ECMO therapy in patients with therapy-refractory cardiogenic shock or in combined cardiopulmonary failure. In this manuscript, the veno-veno-arterial ECMO setup is described in full detail and different venous cannulas are discussed.