Endurance training increases the number of endothelial progenitor cells in patients with cardiovascular risk and coronary artery disease

OBJECTIVE

As regular physical exercise improves endothelial dysfunction and promotes cardiovascular health, we investigated the effect of training on angiogenesis by measuring the number of circulating endothelial progenitor cells (EPC), the level of EPC-mobilizing growth factors and tested vascular function by flow-mediated dilation (FMD) in patients with coronary artery disease (CAD) and cardiovascular risk factors (CVRF). In addition, degradation products of the NO pathway (NOx) were determined.

METHODS AND RESULTS

Twenty patients with documented CAD and/or CVRF joined a 12-week supervised running training. Circulating EPCs--defined by the surface markers CD34, KDR and CD133--were measured at baseline and after exercise training by flow cytometry. We found a significant increase in circulating EPCs (2.9+/-0.4-fold increase; P < .0001), which was positively correlated with both, the change of FMD (r = .81, P < .001) and the increase of NOx synthesis (r = .83, P < .001). Plasma VEGF and erythropoietin did not change in response to exercise. However, we observed a positive correlation between the number of EPCs and erythropoietin at baseline (r = .70, P < .01) and after training (r = .73, P < .01).

CONCLUSIONS

Regular exercise training augments the number of circulating EPCs in patients with CVRF and CAD and is associated with improved vascular function and NO synthesis.

Early basal insulin therapy decreases new-onset diabetes after renal transplantation

No effective interventions to reduce risk for new-onset diabetes after transplantation (NODAT), a condition associated with postoperative hyperglycemia and reduced patient and graft survival, have been established. In this 1-year, proof-of-concept clinical trial, we randomly assigned 50 renal transplant recipients to immediate-postoperative isophane insulin for evening blood glucose ≥140 mg/dl (treatment group) or short-acting insulin and/or oral antidiabetic agents for blood glucose ≥180-250 mg/dl (standard-of-care control group). We included only patients without a history of diabetes who received tacrolimus. By the third postoperative evening, all patients in the treatment group had blood glucose ≥140 mg/dl and were subsequently treated with basal insulin; during the first 3 weeks after transplantation, the mean ± SD daily insulin dosage was 17±11 IU/d. Among controls, 23 (92%) of 25 had blood glucose ≥200 mg/dl and 18 (72%) of 25 received standard-of-care antihyperglycemic treatment. Asymptomatic hypoglycemia occurred five times in the treatment group and once in the control group. Throughout follow-up, the treatment group had 73% lower odds of NODAT (odds ratio, 0.27) than the control group, and hemoglobin A1c was on average 0.38% lower in the treatment group than the control group. Twelve months after transplantation, all patients in the treatment group were insulin-independent, whereas 7 (28%) of 25 controls required antidiabetic agents. The groups did not differ for insulin sensitivity, but the treatment group showed better β-cell function throughout the 1-year follow-up. In conclusion, this study suggests regimens that include basal insulin significantly reduce the odds for NODAT after renal transplantation, presumably via insulin-mediated protection of β cells.

Plasma ghrelin concentrations are not regulated by glucose or insulin: a double-blind, placebo-controlled crossover clamp study

Ghrelin plasma concentrations increase during fasting and fall rapidly after nutrient ingestion. We hypothesized that insulin or glucose could regulate ghrelin secretion by a feedback mechanism. In this randomized, double-blind, placebo-controlled crossover study, three different study days were carried out in nine healthy volunteers (age 26 +/- 6 years). On each day, stepwise increasing systemic glucose concentrations of 5.0, 8.3, and 11.1 mmol/l were attained by intravenous infusion of glucose, representing fasting and postprandial conditions. Ghrelin plasma concentration was studied during concomitant exogenous hyperinsulinemia, inhibition of endogenous insulin production by somatostatin infusion, and placebo time control, respectively. Elevated glucose concentrations increased circulating insulin to 612 +/- 85 pmol/l (P < 0.01), but they did not affect ghrelin concentrations. Prolonged hyperinsulinemia by exogenous infusion resulted in circulating insulin of 1,602 +/- 261 pmol/l (P < 0.01) and suppressed plasma ghrelin to 49.6% of baseline (P < 0.01). During administration of somatostatin, insulin concentration remained constant, but an even greater decrease in ghrelin to 39.5% of baseline was noted (P < 0.01). Hyperglycemia does not decrease ghrelin, and a reduction in ghrelin is only seen at supraphysiological insulin concentrations. In contrast, systemic ghrelin concentrations are decreased by somatostatin. The meal-related suppression of ghrelin appears not directly regulated by glucose or insulin.

Exercise training improves vascular endothelial function in patients with type 1 diabetes

OBJECTIVE-Impaired endothelial function of resistance and conduit arteries can be detected in patients with type 1 diabetes. We studied whether a persistent improvement of endothelial function can be achieved by regular physical training. RESEARCH DESIGN AND METHODS-The study included 26 patients with type 1 diabetes of 20 +/- 10 years' duration and no overt angiopathy; 18 patients (42 +/- 10 years old) participated in a bicycle exercise training program, and 8 patients with type 1 diabetes (33 +/- 11 years old) served as control subjects. Vascular function of conduit arteries was assessed by flow-mediated and endothelium-independent dilation of the brachial artery and of resistance vessels by the response of ocular fundus pulsation amplitudes to intravenous N(G)-monomethyl-L-arginine (L-NMMA) at baseline, after 2 and 4 months of training, and 8 months after cessation of regular exercise. RESULTS-Training increased peak oxygen uptake (VO(2max)) by 13% after 2 months and by 27% after 4 months (P = 0.04). Flow-mediated dilation (FMD) of the brachial artery increased from 6.5 +/- 1.1 to 9.8 +/- 1.1% (P = 0.04) by training. L-NMMA administration decreased fundus pulsation amplitude (FPA) by 9.1 +/- 0.9% before training and by 13.4 +/- 1.5% after 4 months of training (P = 0.02). VO(2max), FMD, and FPA were unchanged in the control group. Vascular effects from training were abrogated 8 months after cessation of exercise. CONCLUSIONS-Our study demonstrates that aerobic exercise training can improve endothelial function in different vascular beds in patients with long-standing type 1 diabetes, who are at considerable risk for diabetic angiopathy. However, the beneficial effect on vascular function is not maintained in the absence of exercise.

Simvastatin blunts endotoxin-induced tissue factor in vivo

BACKGROUND

Beyond lipid lowering, various antiinflammatory properties have been ascribed to statins. Moreover, in vitro studies have suggested the presence of anticoagulant effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, as lipopolysaccharide (LPS)-induced monocyte tissue factor (TF) was suppressed. In this study, we examined the role of statins in experimental endotoxemia on inflammatory and procoagulant responses in vivo.

METHODS AND RESULTS

In this double-blind, placebo-controlled, parallel-group study, 20 healthy, male subjects were randomized to receive either simvastatin (80 mg/d) or placebo for 4 days before intravenous administration of LPS (20 IU/kg IV). Plasma high-sensitive C-reactive protein (hsCRP), monocyte chemoattractant protein (MCP-1), sCD40L, sCD40, and prothrombin fragment F1+2 (F1.2) were determined by ELISAs at baseline and at 4 and 8 hours after LPS administration. Monocyte TF expression and monocyte-platelet aggregates were measured by whole-blood flow cytometry over the same time course. The increases in hsCRP and MCP-1, both known inducers of TF, were significantly suppressed by statin treatment after LPS challenge. Statin premedication blunted the increase of monocyte TF expression in response to LPS. In parallel, endotoxin-induced formation of F1.2 was significantly reduced by simvastatin after 4 and 8 hours. LPS infusion affected neither the formation and activation of monocyte-platelet aggregates nor plasma levels of sCD40 and sCD40L.

CONCLUSIONS

Simvastatin suppresses the inflammatory response to endotoxin and blunts monocyte TF expression but does not affect platelet activation.

Simvastatin suppresses endotoxin-induced upregulation of toll-like receptors 4 and 2 in vivo

In addition to lipid lowering effects, statins appear to have pleiotropic immunomodulatory properties. As they particularly affect monocyte functions, we tested the influence of statin treatment on the monocyte activating toll-like receptors (TLR) 4 and 2 in response to lipopolysaccharides (LPS) in vivo. In this double-blind, placebo-controlled study, 20 healthy, male subjects were randomized to receive either simvastatin (80 mg/day) or placebo for 4 days before intravenous LPS administration (20 IU/kg). Simvastatin did not influence the increase in TLR transcripts after LPS administration measured in mRNA isolated from whole blood by quantitative RT-PCR. In contrast, the parallel upregulation of TLR4 and TLR2 on the surface of monocytes determined by flow cytometry was attenuated by more than half after LPS challenge (P<0.02). Suppressed TLR4 and TLR2 expression was associated with diminished circulating concentrations of tumor necrosis factor-alpha and monocyte chemoattractant protein-1. In conclusion, high-dose simvastatin pretreatment blunted TLR4 and TLR2 expression on monocytes in a human endotoxemia model on a posttranscriptional level. This suppressive effect of statins on key receptors of the innate immunity which was associated with a reduction of effector cytokines reveals a potential mechanism for their beneficial effects in sepsis and cardiovascular disease.

Efficacy and safety of vildagliptin in new-onset diabetes after kidney transplantation--a randomized, double-blind, placebo-controlled trial

New-onset diabetes after transplantation (NODAT) is a serious complication after kidney transplantation, but therapeutic strategies remain underexplored. Dipeptidyl peptidase-4 (DPP-4) inhibitors selectively foster insulin secretion without inducing hypoglycemia, which might be advantageous in kidney transplant recipients (KTRs) with NODAT. We conducted a randomized, double-blind, placebo-controlled, phase II trial to assess safety and efficacy of the DPP-4 inhibitor vildagliptin. Intraindividual differences in oral glucose tolerance test (OGTT)-derived 2-h plasma glucose (2HPG) from baseline to 3 months after treatment served as primary endpoint. Among secondary outcomes, we evaluated HbA1c, metabolic and safety parameters, as well as OGTTs at 1 month after drug discontinuation. Of 509 stable KTRs who were screened in our outpatient clinic, 63 (12.4%) had 2HPG ≥ 200 mg/dL, 33 of them were randomized and 32 completed the study. In the vildagliptin group 2HPG and HbA1c were profoundly reduced in comparison to placebo (vildagliptin: 2HPG = 182.7 mg/dL, HbA1c = 6.1%; placebo: 2HPG = 231.2 mg/dL, HbA1c = 6.5%; both p ≤ 0.05), and statistical significance was achieved for the primary endpoint (vildagliptin: 2HPG-difference -73.7 ± 51.3 mg/dL; placebo: -5.7 ± 41.4 mg/dL; p < 0.01). Adverse events were generally mild and occurred at similar rates in both groups. In conclusion, DPP-4 inhibition in KTRs with overt NODAT was safe and efficient, providing a novel treatment alternative for this specific form of diabetes.

Simvastatin prevents vascular hyporeactivity during inflammation

BACKGROUND

There is growing evidence that statins exert anti-inflammatory and antioxidative vascular actions that are independent of lipid lowering. We tested whether hyporeactivity to the endothelium-dependent vasodilator acetylcholine (ACh) and the vasoconstrictor norepinephrine (NE) during acute experimental inflammation could be prevented by simvastatin.

METHODS AND RESULTS

In a randomized, placebo-controlled, parallel group study, forearm blood flow (FBF) responses to NE, ACh, and the endothelium-independent vasodilator nitroglycerin (NTG) were assessed at baseline, after 4 days of simvastatin 80 mg PO or placebo treatment, and during Escherichia coli endotoxin (lipopolysaccharide [LPS])-induced inflammation in 20 healthy volunteers. Additionally, markers of inflammation and neutrophil oxidative burst were assessed. Simvastatin and placebo had no effect on FBF or oxidative/inflammatory markers. LPS administration decreased the responses of FBF to NE by 43% (P<0.05) and decreased responses to ACh by 48% (P<0.05) but did not decrease FBF responses to NTG. Simvastatin completely preserved responses to NE and to ACh. The LPS-induced increases in neutrophil oxidative burst and plasma tumor necrosis factor-alpha concentrations were mitigated by simvastatin (P<0.05 versus placebo).

CONCLUSIONS

This study demonstrates potent vasoprotective properties of high-dose simvastatin during endotoxemia that may be useful for patients with acute systemic inflammation and associated vascular hyporeactivity.

High doses of vitamin C reverse Escherichia coli endotoxin-induced hyporeactivity to acetylcholine in the human forearm

BACKGROUND

Acute inflammation causes endothelial vasodilator dysfunction that may be mediated by oxidative stress.

METHODS AND RESULTS

In this randomized, double-blind, crossover study, forearm blood flow responses to acetylcholine (ACh) (endothelium-dependent dilator) and glyceryl-trinitrate (GTN) (endothelium-independent dilator) were assessed before and after induction of acute systemic inflammation by low doses of Escherichia coli endotoxin (LPS) (20 IU/kg IV) in 8 healthy volunteers. The acute effect of intra-arterial vitamin C (24 mg/min) or placebo was studied 4 hours after LPS, respectively. Vitamin C alone was administered in control experiments. LPS administration caused systemic vasodilation, increased white blood count, elevated body temperature, and reduced vitamin C plasma concentrations. LPS decreased the responses of forearm blood flow to ACh by 30% (P<0.05) but not to GTN. Vitamin C completely restored the response to ACh, which was comparable with that observed under baseline conditions. Vitamin C had no effect on basal blood flow or ACh- or GTN-induced vasodilation in control subjects.

CONCLUSIONS

Our data demonstrate that impaired endothelial vasodilation caused by E coli endotoxemia can be counteracted by high doses of antioxidants in vivo. Oxidative stress may play an important role in the pathogenesis of endothelial dysfunction during inflammation.

Inflammation-induced vasoconstrictor hyporeactivity is caused by oxidative stress

OBJECTIVES

We sought to determine the role of oxidative stress in the development of vascular dysfunction in inflammation.

BACKGROUND

Hyporeactivity to catecholamines and other vasoconstrictors is present in acute inflammation. Because oxidative stress plays a significant role in inflammation, impaired responsiveness may be overcome by anti-oxidants.

METHODS

In randomized, double-blind, cross-over studies, forearm blood flow (FBF) responses to norepinephrine (NE), angiotensin II (ANG II), and vasopressin (VP) were assessed before and 4 h after induction of systemic inflammation by low doses of Escherichia coli endotoxin (lipopolysaccharide [LPS], 20 IU/kg intravenously) or after placebo in healthy volunteers. Furthermore, the effect of intra-arterial vitamin C (24 mg/min) or placebo on NE-induced or ANG II-induced vasoconstriction was studied after LPS.

RESULTS

Administration of LPS caused systemic and forearm vasodilation, increased white blood cell count, elevated body temperature, and reduced vitamin C plasma concentrations. Lipopolysaccharide decreased the responses of FBF to NE by 59%, to ANG II by 25%, and to VP by 51% (n = 9, p < 0.05, all effects). Co-administration of vitamin C completely restored the response to NE and to ANG II, which was comparable to that observed under baseline conditions (n = 8).

CONCLUSIONS

E. coli-endotoxemia reduces FBF responsiveness to vasoconstrictors. The hyporeactivity can be corrected by high doses of vitamin C, suggesting that oxidative stress may represent an important target for inflammation-induced impaired vascular function.

Adrenoceptor hyporeactivity is responsible for Escherichia coli endotoxin-induced acute vascular dysfunction in humans

Impaired response to catecholamines contributes to the altered hemodynamics in sepsis, which has been attributed to excessive NO formation. We have studied the systemic hemodynamic and local forearm responses and inducible NO synthase (iNOS) expression during experimental endotoxemia in humans. Escherichia coli endotoxin (lipopolysaccharide [LPS]) was administered at doses of 1 or 2 ng/kg to healthy volunteers. In 10 subjects, the systemic pressor effect of phenylephrine was assessed before and after the administration of LPS. In 9 further subjects, forearm blood flow responses to intra-arterial noradrenaline, acetylcholine, glyceryl trinitrate, and N(G)-monomethyl-L-arginine (L-NMMA) were studied at baseline and after LPS administration. Peripheral blood was collected and analyzed for iNOS mRNA and protein. Four hours after LPS, the response of systolic blood pressure (P<0.0005) and heart rate (P<0.05) to phenylephrine was significantly reduced. In the forearm, noradrenaline-induced vasoconstriction was also reduced by approximately 50% (P<0.01), but L-NMMA responsiveness was unchanged. iNOS mRNA or protein was not increased. Marked vascular adrenoceptor hyporeactivity is detectable in the absence of increased NO activity or iNOS expression in endotoxemia, arguing against major involvement of vascular iNOS activity in the acute systemic vasodilation to LPS.

Functional and biochemical properties of chronically stimulated human skeletal muscle

The present study was undertaken to investigate in a randomized controlled trial the effects of chronic (10 weeks, 4 h per day, 7 days per week) low-frequency (15 Hz) stimulation (CLFS) of the knee extensor and hamstring muscles of both legs in healthy volunteers via surface electrodes. A control group (n=10) underwent the same treatment (sham stimulation) as the CLFS-treated group (n=10), except that stimulation intensity was kept at a level which did not evoke contractions. Biopsy samples were taken before the onset and after cessation of stimulation from the right vastus lateralis muscle of all subjects. The biopsy samples were analyzed for changes in myosin heavy chain (MHC) isoforms and activities of citrate synthase (CS) and glyceraldehyde phosphate dehydrogenase (GAPDH) as markers of aerobic-oxidative and anaerobic pathways of energy metabolism, respectively. In addition, functional properties, i.e., oxygen consumption (VO(2)) and work capacity, were assessed. Sham stimulation did not affect the functional properties and had no detectable effect on MHC isoform and enzyme activity patterns. Conversely, CLFS induced changes in the MHC isoform pattern in the fast-to-slow direction with an approximately 20% decrease in the relative concentration of MHCIId/x (from 28% to 22%) and an approximately 10% increase in the relative concentration of MHCI (from 30% to 34%). In addition, CLFS led to a approximately 9% increase in the activity of CS concomitant with an approximatley 7% decrease in the activity of GAPDH. This increase in aerobic-oxidative capacity was accompanied by improved work capacity and VO(2) at the anaerobic threshold by 26% and 20%, respectively.

Regular physical exercise improves endothelial function in heart transplant recipients

BACKGROUND

Impaired endothelial function is detectable in heart transplant (HTX) recipients and regarded as risk factor for coronary artery disease. We have studied whether endothelial function can be improved in HTX patients participating in a regular physical training program as demonstrated in patients with chronic heart failure, hypertension and coronary artery disease.

METHODS

Male HTX patients and healthy, age-matched controls were studied. Seven HTX patients (age: 60 +/- 6 yr; 6 +/- 2 yr of HTX) participated in an outpatient training program, six HTX patients (age: 63 +/- 8 yr; 7 +/- 1 yr of HTX) maintained a sedentary lifestyle without regular physical exercise since transplantation. A healthy control group comprised six subjects (age: 62 +/- 6 yr). Vascular function was assessed by flow-mediated dilation of the brachial artery (FMD). Systemic haemodynamic responses to intravenous infusion of the endothelium independent vasodilator sodium nitroprusside (SNP) and to NG-monomethyl-L-arginine (L-NMMA), an inhibitor of constitutive nitric oxide synthase, were also measured.

RESULTS

Resting heart rate was significantly lower (p < 0.05) in healthy controls (66 +/- 13) than in the HTX training group (83 +/- 11) and in non-training HTX patients (91 +/- 9), baseline blood pressure also tended to be lower in healthy subjects and in the training HTX patients. FMD was significantly higher (p < 0.05) in the control group (8.4 +/- 2.2%) and in the training group (7.1 +/- 2.4%), compared with non-training HTX patients (1.4 +/- 0.8%). The response of systolic blood pressure (p = 0.08) and heart rate (p < 0.05) to L-NMMA was reduced in sedentary HTX patients compared with healthy controls and heart rate response to SNP was also impaired in sedentary HTX patients.

DISCUSSION

Regular aerobic physical training restores vascular function in HTX patients, who are at considerable risk for developing vascular complications. This effect is demonstrable in conduit and systemic resistance arteries.

Exercise training lowers plasma visfatin concentrations in patients with type 1 diabetes

CONTEXT

Exercise training exerts beneficial effects on metabolic and vascular risk factors in patients with type 1 diabetes mellitus (T1DM). It is unknown whether training also influences concentrations of visfatin, a novel insulin-mimetic adipocytokine.

OBJECTIVES

In this study, we have investigated whether plasma visfatin concentrations are altered by training in patients with T1DM.

DESIGN AND PATIENTS

Fasting plasma visfatin concentrations and metabolic parameters were measured in 18 patients with T1DM who participated in a supervised aerobic exercise program for 4 months. Three subjects discontinued training prematurely after 2 months. Samples were obtained before and during training and 8 months after the end of regular exercise. Fourteen healthy young subjects served as controls.

RESULTS

At baseline, patients with T1DM had higher visfatin concentrations than controls (64.1 +/- 12.0 vs. 1.3 +/- 0.0 ng/ml, P < 0.01). Exercise reduced visfatin after 2 and 4 months to 27.8 +/- 2.6 (n = 18) and 17.5 +/- 3.4 ng/ml (n = 15), respectively (P < 0.001 for n = 15 subjects who participated in all visits, ANOVA). This effect was maintained 8 months after cessation of training, with visfatin concentrations of 19.7 +/- 5.0 ng/ml (n = 15). Metabolic parameters were not affected by the training program.

CONCLUSION

Elevated visfatin concentrations in patients with T1DM can be lowered by regular physical exercise. It is unknown whether glucose tolerance is affected by changes in visfatin concentrations.

FFA-induced endothelial dysfunction can be corrected by vitamin C

Insulin resistance is associated with an inappropriate elevation of plasma FFA and endothelial dysfunction. FFA could stimulate formation of reactive oxygen species, which could be responsible for vascular impairment. In this randomized, double-blind, cross-over study in 10 healthy volunteers (24 +/- 3 yr old), forearm blood flow (FBF) responses to intraarterial acetylcholine (ACh) and glyceryl trinitrate were assessed with coadministration of vitamin C (24 mg/ml) or placebo, respectively, in the presence of increased plasma FFA induced by Intralipid/heparin infusion. The rise in plasma FFA from 320 +/- 64 to 1852 +/- 232 micromol/liter was associated with a reduced response of FBF to ACh by 55% (P < 0.01). During coadministration of vitamin C, the impaired responsiveness of FBF to ACh was completely reversed and not different from that observed under baseline conditions. Vitamin C did not affect plasma FFA concentrations. Glyceryl trinitrate responsiveness was unchanged during FFA elevation, with or without vitamin C. These data suggest that FFA-induced vascular oxidative stress could contribute to endothelial dysfunction in insulin-resistant patients. High concentrations of antioxidants are able to reverse the local effects of FFA on endothelium-dependent vasodilation.

Acute Escherichia coli endotoxaemia decreases the plasma l-arginine/asymmetrical dimethylarginine ratio in humans

Acute inflammation impairs vascular function. Based on the association between endothelial dysfunction and plasma concentrations of L-arginine and the endogenous nitric oxide synthase inhibitor ADMA (asymmetrical dimethylarginine), we hypothesized that the ratio between L-arginine and ADMA could be affected by experimental inflammation. Plasma concentrations of L-arginine, ADMA and SDMA (symmetrical dimethylarginine) were studied at baseline and 3.5 h after intravenous administration of Escherichia coli endotoxin [LPS (lipopolysaccharide), 20 units/kg of body mass; n=8] or placebo (n=9) in healthy males. L-Arginine and dimethylarginines were quantified after solid-phase extraction by reversed-phase HPLC. Body temperature, heart rate and leucocyte count increased after LPS administration (P<0.01 for all). LPS administration decreased plasma concentrations of L-arginine from 66 µmol/l [95% CI (confidence interval): 56, 88] at baseline to 48 µmol/l (CI: 40, 60) after 3.5 h (P<0.02), but did not affect ADMA and SDMA concentrations. Consequently, the L-arginine/ADMA ratio declined significantly from a median of 159 (CI: 137, 193) to 135 (CI: 103, 146); a decrease of 25 (CI: -68, -13; P<0.02). L-Arginine, ADMA, SDMA and the L-arginine/ADMA ratio remained constant over time in controls. Acute inflammation reduces the L-arginine/ADMA ratio which could contribute to impaired vascular function.

Alpha-lipoic acid improves vascular endothelial function in patients with type 2 diabetes: a placebo-controlled randomized trial

OBJECTIVE

The aim of this study was to investigate the effect of alpha-lipoic acid (ALA) treatment on endothelium-dependent and -independent vasodilatation, assessed by forearm blood flow (FBF), in patients with type 2 diabetes mellitus.

RESEARCH DESIGN AND METHODS

A total of 30 subjects with type 2 diabetes were included in this randomized, controlled, double-blinded, parallel group study. FBF responses to intra-arterial acetylcholine (ACh) and glycerol trinitrate (GTN) were measured before and after 21 days of intravenous treatment with 600 mg alpha-lipoic acid or placebo.

RESULTS

FBF responses were comparable at baseline. After treatment, FBF reactivity to ACh and GTN was unchanged in subjects receiving placebo. By contrast, ALA treatment increased endothelium-dependent vasodilatation to ACh (P < 0.05) but not to GTN compared with baseline.

CONCLUSIONS

Intravenous ALA treatment improves endothelium-dependent vasodilatation in patients with type 2 diabetes, in the absence of effects on forearm vasomotor function. If this salutary action translates into vascular risk reduction remains to be established.

Intra-arterial vitamin C prevents endothelial dysfunction caused by ischemia-reperfusion

OBJECTIVE

Ischemia-reperfusion (IR) injury causes tissue injury and endothelial dysfunction. There is evidence that oxidative stress plays an important role.

METHODS

We tested if IR-induced endothelial dysfunction could be prevented by administration of the antioxidant vitamin C. Twenty-six healthy male subjects and eight male patients with peripheral arterial disease (PAD) were enrolled in this randomised placebo-controlled study. Forearm blood flow (FBF) measurements in response to the vasodilators acetylcholine (ACh; endothelium-dependent agonist) or nitroglycerin (NTG; endothelium-independent) were performed before and after forearm ischemia for 20 min. FBF responses were reassessed during reperfusion with intra-arterial co-administration of 24 mg/min vitamin C or placebo. In six volunteers responses to the NO-synthase inhibitor N-monomethyl-L-arginine (L-NMMA) were also assessed before and after ischemia with and without vitamin C.

RESULTS

ACh-induced vasodilation was blunted in subjects receiving placebo after reperfusion (p<0.05 versus baseline). Administration of vitamin C completely prevented impaired responsiveness. NTG-induced vasodilation was not affected by reperfusion or vitamin C. This finding was consistent in patients with PAD and impaired endothelial function, where local vitamin C infusion restored FBF reactivity to ACh before and after IR injury (p<0.05 versus baseline). Again, NTG-induced vasodilation was not affected. Blunted L-NMMA responses seen during reperfusion could be completely reversed by vitamin C.

CONCLUSIONS

Our data indicate that IR-induced vascular injury can be prevented by administration of antioxidants.

Electromagnetic interference by transcutaneous neuromuscular electrical stimulation in patients with bipolar sensing implantable cardioverter defibrillators: a pilot safety study

Neuromuscular electrical stimulation (NMES) is a frequently applied therapy for the treatment of pain and a therapeutic option to increase thigh muscle strength and endurance capacity in patients with heart failure. Electromagnetic interference (EMI) by the signals with sensing of ICDs is possible. Eight patients with subpectoral ICD systems and different transvenous bipolar sensing leads were subjected to electrical stimulation of the neck and shoulder and of the thighs using different stimulation algorithms. EMI with ventricular sensing was detectable in three of eight subjects. EMI occurred during stimulation of the neck (n = 2) and thigh (n = 2). EMI by NMES with atrial sensing was seen in two of four subjects with dual chamber ICDs. The safety of peripheral NMES has to be individually tested as EMI can also occur in ICD patients with bipolar sensing.

Tetrahydrobiopterin corrects Escherichia coli endotoxin-induced endothelial dysfunction

Acute inflammation causes endothelial dysfunction, which is partly mediated by oxidant stress and inactivation of nitric oxide. The contribution of depletion of tetrahydrobiopterin (BH(4)), the cofactor required for nitric oxide generation, is unclear. In this randomized, double-blind, three-way crossover study, forearm blood flow (FBF) responses to ACh and glyceryltrinitrate (GTN) were measured before and 3.5 h after infusion of Escherichia coli endotoxin (LPS, 20 IU/kg iv) in eight healthy men. The effect of intra-arterial BH(4) (500 microg/min), placebo, or vitamin C (24 mg/min) was studied on separate days 3.5 h after LPS infusion. In addition, human umbilical vein endothelial cells were incubated for 24 h with vitamin C and LPS. ACh and GTN caused dose-dependent forearm vasodilation. The FBF response to ACh, which was decreased by 23 +/- 17% (P < 0.05) by LPS infusion, was restored to baseline reactivity by BH(4) and vitamin C. FBF responses to GTN were not affected by BH(4) or vitamin C. LPS increased leukocyte count, high-sensitivity C-reactive protein, IL-6, IL-1beta, IFN-gamma, monocyte chemoattractant protein-1, pulse rate, and body temperature and decreased platelet count and vitamin C concentration. Vitamin C increased forearm plasma concentration of BH(4) by 32% (P < 0.02). Incubation with LPS and vitamin C, but not LPS alone, increased intracellular BH(4) concentration in human umbilical vein endothelial cells. Impaired endothelial function during acute inflammation can be restored by BH(4) or vitamin C. Vitamin C may exert some of its salutary effects by increasing BH(4) concentration.

Rosiglitazone prevents free fatty acid-induced vascular endothelial dysfunction

CONTEXT

Free fatty acids (FFAs) cause insulin resistance and vascular endothelial dysfunction. The peroxisome proliferator-activated receptor gamma agonist rosiglitazone acts as insulin sensitizer and could exert vasoprotective properties by preservation of endothelium-dependent vasodilation.

OBJECTIVE

We tested the effect of rosiglitazone on FFA-induced endothelial dysfunction of the forearm resistance vessels, insulin sensitivity, asymmetric dimethylarginine (ADMA), and high-sensitivity C-reactive protein concentrations in humans.

DESIGN AND SETTING

We conducted a double-blind, randomized, placebo-controlled parallel-group study at a university hospital.

PATIENTS AND INTERVENTIONS

Rosiglitazone 8 mg daily or placebo was administered to 16 healthy male subjects for 21 d. On the last day, triglycerides and heparin were infused iv to increase FFA plasma concentrations.

MAIN OUTCOME MEASURES

Forearm blood flow responses to the endothelium-dependent vasodilator acetylcholine and the endothelium-independent vasodilator nitroglycerine were assessed using strain-gauge plethysmography at baseline, and on d 21 before and after 5 h of triglyceride/heparin infusion.

RESULTS

Forearm blood flow reactivity was not affected by rosiglitazone or placebo. Infusion of triglyceride/heparin substantially increased FFA concentrations (P < 0.001) and reduced endothelium-dependent vasodilation by 38 +/- 17% (P = 0.024). In the face of lower FFA elevation (P = 0.047 vs. controls), endothelium-dependent vasodilation was preserved in subjects receiving rosiglitazone (P = 0.016 vs. placebo). Endothelium-independent vasodilation and C-reactive protein were unchanged, whereas insulin sensitivity and plasma ADMA similarly decreased in both study groups after FFA elevation (both P < 0.05 vs. baseline).

CONCLUSIONS

Rosiglitazone mitigates the increase in FFA after infusion of triglyceride/heparin and prevents FFA-induced endothelial dysfunction. These effects are independent and possibly occur before any changes in insulin sensitivity and ADMA plasma concentrations in healthy subjects.

Regular physical exercise normalizes elevated asymmetrical dimethylarginine concentrations in patients with type 1 diabetes mellitus

INTRODUCTION

Levels of the endogenous nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA) are elevated in patients with type 1 diabetes mellitus (DM1) and may contribute to vascular complications. In this study we tested the hypothesis that elevated ADMA in patients with DM1 can be reduced by regular physical exercise.

METHODS

Plasma samples for analysis of L-arginine, ADMA, symmetrical dimethylarginine (SDMA) and metabolic parameters were obtained from 11 patients with DM1 who participated in a supervised aerobic exercise program for four months. Samples were collected before the training began, at two and four months after initiation, and eight months after cessation of regular training. Fifteen age- and sex-matched healthy persons who did not exercise regularly were examined once as controls and did not participate in the training program.

RESULTS

The patients with DM1 had higher ADMA levels than the controls before the training program began (0.54 +/- 0.02 vs. 0.44 +/- 0.03 micromol/l; P < 0.05). After two and four months of exercise, ADMA concentrations in the patients decreased to those seen in healthy persons (0.42 +/- 0.02 and 0.43 +/- 0.03 micromol/l; P < 0.001 and P < 0.05 compared with ADMA levels before training began). Eight months after cessation of the exercise program, ADMA levels in the patients reverted to those observed before the start of training. The L-arginine-to-ADMA ratio increased slightly after two months; L-arginine, symmetrical dimethylarginine, blood lipids and HbA1c were not affected by the training program.

CONCLUSIONS

Elevated ADMA levels in patients with DM1, who have a high risk for developing cardiovascular disease, can be lowered to those of healthy persons by regular physical exercise. This favorable effect on ADMA is not sustained when training is discontinued.

Extracorporeal shockwave treatment is effective in calcific tendonitis of the shoulder. A randomized controlled trial

BACKGROUND

Calcific tendonitis of the shoulder is often associated with chronic pain and impairment of function. Extracorporeal shockwave therapy (ESWT) is considered to be a treatment option. We compared the effects of two different ESWT regimens.

METHODS

43 patients (57 shoulders) with symptomatic calcific tendonitis of the shoulder for more than six months were included in a double-blinded study. Thirty-one shoulders were treated at the area of maximum pain with application of 2 x 2000 impulses of 0.28 mJ/mm2 at an interval of two weeks (treatment group) and 26 shoulders with 2 x 2000 impulses of < 0.07 mJ/mm2 at an interval of two weeks (control group), without pretreatment analgesia. Shoulder function (Constant score) and pain (visual analogue scale, VAS) were assessed before treatment and at one week, three months and seven months after treatment. Shoulder X-rays were performed at the 3- and 7-month follow-up visits.

RESULTS

Improvement in Constant score was significantly higher in the treatment group at all follow-up visits (p < 0.05). Seven months post-treatment, calcifications dissolved completely in 19% of the treatment group and 8% of the control group, and a > 50% reduction was observed in 19% and 8% respectively. With regard to reduction of pain, there was significant improvement in the treatment group compared with the control group at the 1-week follow-up (p < 0.05). However, at the 3-month and 7-month visits, no significant between-group difference in pain could be detected.

CONCLUSION

As applied, ESWT with an energy flux density of 0.28 mJ/mm2 led to a significantly greater improvement in shoulder function and a slightly higher, nonsignificant, rate of > 50% disintegration of calcific deposits compared with the control group. However, this did not result in reduction of pain.

Regulation of Fas (APO-1, CD95) and Fas ligand expression in leukocytes during systemic inflammation in humans

A potential role of Fas/FasL in sepsis is suggested by recent clinical studies showing that Fas and FasL could serve as markers for severity of sepsis. We sought to determine the effect of endotoxin infusion on expression of Fas and FasL. Healthy volunteers (n = 30) received 2 ng/kg endotoxin i.v. Endotoxin infusion decreased Fas expression on neutrophils and monocytes by 15-20% at 2-4 h in vivo and also in vitro. A rebound increase in Fas (30%) was seen on neutrophils at 24 h, and soluble FasL levels increased by 100% at 24 h. Fas mRNA levels increased 6-fold 4-6 h after endotoxin infusion as measured by real-time polymerase chain reaction. In contrast, FasL-mRNA levels in circulating leukocytes decreased by >80% 2h after lipopolysaccharide infusion. In summary, low-grade endotoxemia induces early down-modulation of Fas on leukocytes, followed by a several-fold increase in Fas-mRNA expression leading to later Fas surface upregulation on neutrophils. The upregulation of Fas expression, Fas mRNA, and later in FasL and sFas levels in endotoxemia replicates the increased fas levels found in septic patients.

Actovegin®: a biological drug for more than 5 decades

Actovegin(®) is a biological drug manufactured from a natural source: it is a calf blood hemodialysate. Its therapeutic benefits stem from a variety of pharmacodynamic actions that can be summarized to a common goal, i.e. the enhancement of cellular metabolism; this results from an insulin-like activity mediated by Inositol-phospho-oligosaccharides. Actovegin(®) results in beneficial effects in several pathophysiological clinical settings including malfunction of the blood circulation and trophic disturbances in the brain, impairment of peripheral blood circulation and associated diseases, dermal transplants and acute and chronic wounds. Here, we give an overview of the pharmacodynamic actions of calf-blood hemidialysate and its beneficial effects in a variety of clinical settings.