Impaired endothelium-dependent skin microvascular function during high-dose atorvastatin treatment in patients with type 1 diabetes

Skin microvascular reactivity and subendocardial viability ratio in relation to dyslipidemia and signs of insulin resistance in non-diabetic hypertensive patients

OBJECTIVE

The aim of this study was to evaluate the influence of dyslipidemia and insulin resistance for the development of microvascular dysfunction in non-diabetic primary hypertension.

METHODS

Seventy-one patients with untreated primary hypertension were included. Skin microvascular reactivity was evaluated by laser Doppler fluxmetry with iontophoresis (acetylcholine, ACh and sodium nitroprusside, SNP) and heat-induced hyperemia. Myocardial microvascular function was estimated by the subendocardial viability ratio (SEVR) calculated from pulse wave analysis and applanation tonometry. Triglyceride x glucose (TyG index) and triglyceride/HDL cholesterol ratio were used as measurements of insulin resistance.

RESULTS

Skin microvascular dysfunction was associated with low HDL cholesterol, where Ach-mediated peak flux (r = .27, p = .025) and heat-induced peak flux (r = .29, p = .017) related to HDL cholesterol levels. ACh peak flux was inversely related to TG/HDL ratio (r = -.29, p = .016), while responses to local heating and SNP did not. SEVR did not relate to HDL and was unrelated to markers of insulin resistance. These findings were confirmed by multivariable analyses, including potential confounders.

CONCLUSIONS

Early microvascular dysfunction can be detected in non-diabetic hypertensive patients and is related to dyslipidemia and to signs of insulin resistance, thus predicting future cardiovascular risk.

Endothelial dysfunction sustains immune response in atherosclerosis: potential cause for ineffectiveness of prevailing drugs

Vascular endothelial dysfunction (ED) forms the cornerstone in the development of atherosclerotic lesions that clinically manifest as ischemia, myocardial infarction, stroke or peripheral arterial disease. ED can be triggered by various risk factors including hypercholesterolemia, hypertension, hyperhomocystenemia and chronic low-grade inflammation. These risk factors also activate immune response systemically. Current drugs used for managing atherosclerosis not only aid in subsiding the risk factor but also suppress the immune activation. Nonetheless, their effectiveness in treating ED is still questionable. Here, we discuss how pathologic molecules and processes pertaining to ED can activate innate and adaptive arms of the immune system leading to disease progression even in the absence of cardiovascular risk factors and the potential of the current drugs, used in the management of atherosclerotic patients, in reversing them. We mainly focus on activated endothelium, endothelial microparticles, mechanically stretched endothelial cells, endothelial mesenchymal transition and endothelial glycocalyx sheds.

Skin microvascular reactivity correlates to clinical microangiopathy in type 1 diabetes: A pilot study

AIM

The aim of this study was to investigate the correlation between skin microvascular reactivity and clinical microangiopathy in patients with type 1 diabetes.

METHODS

We included 61 patients with type 1 diabetes, that is, 31 patients with and 30 without clinical microangiopathy, and 31 healthy controls. A microangiopathy scoring system was introduced for comparison of data between patients with microangiopathy. Responses to iontophoresis of acetylcholine and sodium nitroprusside were assessed by laser Doppler imaging.

RESULTS

Patients with microangiopathy had reduced acetylcholine- and sodium nitroprusside-mediated flux in forearm skin microcirculation compared to healthy controls (p = 0.03 and p < 0.001, respectively, repeated measures analysis of variance), whereas no significant differences were found between patients without microangiopathy and controls. Skin reactivity was reduced in patients with microangiopathy compared to patients without microangiopathy: 1.43 ± 0.38 versus 1.59 ± 0.39 arbitrary units for acetylcholine-mediated peak flux and 1.44 ± 0.46 versus 1.74 ± 0.34 arbitrary units for sodium nitroprusside-mediated peak flux (p < 0.05 for both). A tendency of gradual decrease in acetylcholine and sodium nitroprusside responses was found in patients with increasing microangiopathy scores.

CONCLUSION

We conclude that skin microvascular reactivity is associated with clinical microangiopathy in patients with type 1 diabetes. Impaired skin microvascular function in type 1 diabetes seems to be multifactorial and involves both endothelial-dependent and endothelial-independent pathways. We introduce a novel microangiopathy score that could easily be used in a clinical setting for comparison of patients with various degrees of microangiopathy.

Changes in microparticle profiles by vitamin D receptor activation in chronic kidney disease - a randomized trial

Background

Microparticles (MPs) are biomarkers and mediators of disease through their expression of surface receptors, reflecting activation or stress in their parent cells. Endothelial markers, ICAM-1 and VCAM-1, are implicated in atherosclerosis and associated with cardiovascular risk. Chronic kidney disease (CKD) patients have endothelial dysfunction and high levels of endothelial derived MPs. Vitamin D treatment has been reported to ameliorate endothelial function in CKD patients. We aimed to examine cell specific MP profiles and concentrations of MPs expressing the atherosclerotic markers ICAM-1 and VCAM-1 after treatment with paricalcitol in patients with CKD stage 3–4.

Methods

Sub-study of the previously reported SOLID trial where 36 patients were randomly assigned to placebo, 1 or 2 μg paricalcitol, for 12 weeks. MPs were measured by flow cytometry after labelling with antibodies against endothelial (CD62E), platelet (CD62P, CD41, CD154) leukocyte (CD45) and vascular (CD54, CD106) markers.

Results

Patients had a mean age of 65 years with a mean eGFR of 40 mL/min/1.73m². Concentrations of ICAM-1 positive MPs were significantly reduced by treatment (repeated measures ANOVA p = 0.04). Repeated measures MANOVA of concentrations of endothelial, platelet and leukocyte MPs showed sustained levels in the 2 μg treatment group (p = 0.85) but a decline in the 1 μg (p = 0.04) and placebo groups (p = 0.005).

Conclusions

Treatment with paricalcitol reduces concentrations of ICAM-1 positive MPs. This is accompanied by sustained concentrations of all cell specific MPs in the 2 μg group, and decreasing concentrations in the other groups, possibly due to a more healthy and reactive endothelium with paricalcitol treatment.

Is Atorvastatin Associated with New Onset Diabetes or Deterioration of Glycemic Control? Systematic Review Using Data from 1.9 Million Patients

BACKGROUND

Current evidence indicates that statins increase the risk of new onset diabetes mellitus (NOD) and also deteriorate the glycemic control in patients with known diabetes mellitus (DM) after high-dose statin therapy.

AIMS

The aim of this review was to explore the effect of atorvastatin in causing NOD or deteriorating glycemic control in patients with DM.

METHODS

Two independent reviewers conducted the literature search, through PubMed database searching for articles published in English until April 2015, and only primary studies were included.

RESULTS

Of the 919 articles identified in our original search, 33 met the criteria for this review encompassing 1,951,113 participants. Twenty articles examined dysregulation of DM due to atorvastatin. Half of them showed that there was no significant change in glycemic control in patients treated with atorvastatin. Other studies showed that fasting plasma glucose and HbA1c levels were increased by atorvastatin. Thirteen articles examined if atorvastatin causes NOD. The majority of these articles showed that patients who used atorvastatin had a higher dose-dependent risk of developing NOD.

CONCLUSION

This systematic review suggests that there is an association between atorvastatin treatment and NOD. Moreover, it showed that atorvastatin in high dose causes worsening of the glycemic control in patients with DM.

Pregnancy-associated plasma protein-A is positively correlated with first-trimester skin microvascular reactivity

OBJECTIVE

To investigate the relationship between levels of circulating maternal pregnancy-associated plasma protein-A (PAPP-A) and first-trimester maternal vascular function.

METHODS

This was a cross-sectional study of 53 healthy, non-smoking, nulliparous pregnant women in Stockholm, Sweden. PAPP-A levels and vascular function were assessed during gestational weeks 11-14. Forearm skin microcirculation was investigated by laser Doppler perfusion imaging during iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) to assess endothelium-dependent and -independent microvascular vasodilatation, respectively. Microvascular endothelial function index was calculated as peak ACh/peak SNP. Endothelium-dependent and -independent vasodilatation in the brachial artery was evaluated, respectively, by postischemic hyperemia-induced flow-mediated vasodilatation (FMD) and by response to sublingual intake of glyceryl trinitrate (GTN).

RESULTS

PAPP-A was correlated with skin microvascular endothelial function index (β = 1.008 (95% CI, 0.34-1.68), r²  = 0.17, P = 0.004). PAPP-A also correlated inversely with FMD (β = -0.052 (95% CI, -0.094 to -0.011), r²  = 0.13, P = 0.014) but did not relate to forearm endothelial function index (i.e. FMD/GTN). The results were retained in multivariate analyses including known confounding factors.

CONCLUSIONS

First-trimester endothelium-dependent skin microvascular reactivity was positively related to PAPP-A levels. If confirmed, these novel findings suggest that first-trimester skin microvascular reactivity could be a useful early pregnancy marker of placental function. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Statin Therapy Negatively Impacts Skeletal Muscle Regeneration and Cutaneous Wound Repair in Type 1 Diabetic Mice

Those with diabetes invariably develop complications including cardiovascular disease (CVD). To reduce their CVD risk, diabetics are generally prescribed cholesterol-lowering 3-hydroxy-methylglutaryl coenzyme A reductase inhibitors (i.e., statins). Statins inhibit cholesterol biosynthesis, but also reduce the synthesis of a number of mevalonate pathway intermediates, leading to several cholesterol-independent effects. One of the pleiotropic effects of statins is the reduction of the anti-fibrinolytic hormone plasminogen activator inhibitor-1 (PAI-1). We have previously demonstrated that a PAI-1 specific inhibitor alleviated diabetes-induced delays in skin and muscle repair. Here we tested if statin administration, through its pleiotropic effects on PAI-1, could improve skin and muscle repair in a diabetic rodent model. Six weeks after diabetes onset, adult male streptozotocin-induced diabetic (STZ), and WT mice were assigned to receive control chow or a diet enriched with 600 mg/kg Fluvastatin. Tibialis anterior muscles were injured via Cardiotoxin injection to induce skeletal muscle injury. Punch biopsies were administered on the dorsal scapular region to induce injury of skin. Twenty-four days after the onset of statin therapy (10 days post-injury), tissues were harvested and analyzed. PAI-1 levels were attenuated in statin-treated diabetic tissue when compared to control-treated tissue, however no differences were observed in non-diabetic tissue as a result of treatment. Muscle and skin repair were significantly attenuated in Fluvastatin-treated STZ-diabetic mice as demonstrated by larger wound areas, less mature granulation tissue, and an increased presence of smaller regenerating muscle fibers. Despite attenuating PAI-1 levels in diabetic tissue, Fluvastatin treatment impaired cutaneous healing and skeletal muscle repair in STZ-diabetic mice.

Skin microvascular function in patients with type 1 diabetes: An observational study from the onset of diabetes

BACKGROUND

The development of disturbances in skin microcirculation in type 1 diabetes is not well characterised. We assessed skin microcirculation longitudinally from the onset of diabetes up to 29 years of duration to investigate when such disturbances start.

MATERIAL AND METHODS

Seventeen adult patients with type 1 diabetes participated. Skin microvascular function in digit IV of the left hand was investigated by laser Doppler fluxmetry (LDF, arbitrary units [AU]). LDF was carried out at rest and following one-min arterial occlusion. Time to peak LDF (s) and percentage increase of LDF (post-occlusive reactive hyperaemia, PRH%) were determined. Retinopathy was assessed from fundus photographs or ophthalmoscopic recordings.

RESULTS

Skin microvascular function remained normal during the first five years. Compared with baseline and a non-diabetic reference group, time to peak LDF was prolonged after 7-9 years of diabetes ( p < 0.01). PRH% was lower than in the reference group after 7-9 years ( p < 0.01), and lower than baseline after 24-29 years of diabetes ( p < 0.05). All but one patient developed retinopathy and the first signs were found after 10 years of diabetes.

CONCLUSIONS

Functional disturbances in total skin microcirculation were observed after seven years in patients with type 1 diabetes and preceded diabetic complications such as retinopathy.

Longitudinal study of vascular structure and function during normal pregnancy

OBJECTIVE

To examine alterations in maternal vascular structure and function during normal pregnancy.

METHODS

We assessed brachial and central blood pressure, pulse-wave velocity and augmentation index (by pulse-wave analysis and applanation tonometry), common carotid artery structure (by ultrasonography) and endothelial function in the brachial artery (by postischemic hyperemia-induced flow-mediated vasodilatation by glyceryl trinitrate) and in the forearm skin microcirculation (by laser Doppler perfusion imaging during iontophoretic administration of acetylcholine and sodium nitroprusside) in 52 healthy nulliparous women at 14, 24 and 34 weeks' gestation, and at 9 months postpartum.

RESULTS

During pregnancy, brachial and central systolic and diastolic blood pressures initially decreased but subsequently increased (all P < 0.05). Flow-mediated vasodilatation in the brachial artery increased during early pregnancy (P < 0.05), whereas non-specific vasodilatation by glyceryl trinitrate decreased (P < 0.01), indicating improved endothelial function. Thus, endothelial function index (forearm blood flow/glyceryl trinitrate) increased during pregnancy (0.30 ± 0.18 in the non-pregnant state at 9 months postpartum and 0.51 ± 0.19, 0.61 ± 0.39 and 0.49 ± 0.30 in the first, second and third trimesters, respectively) (P < 0.001). Endothelium-dependent skin microvascular reactivity to acetylcholine also increased (P < 0.01). Carotid-femoral pulse-wave velocity decreased during pregnancy (5.88 ± 0.91 m/s in the non-pregnant state and 5.55 ± 0.67, 5.12 ± 0.66 and 5.62 ± 0.74 m/s in the first, second and third trimesters, respectively) (P < 0.001).

CONCLUSION

During normal pregnancy, the blood volume expansion necessary for sufficient fetal growth is accommodated by early and marked changes in the matvascular system. This seems to be dependent on normal adaptive endothelial and vascular function. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Fetal growth is associated with first-trimester maternal vascular function

OBJECTIVE

To investigate the relationship between maternal endothelial function in the first trimester, assessed in both the brachial artery and the forearm skin microcirculation, and fetal growth.

METHODS

Vascular function was assessed in 56 pregnant women during gestational weeks 11-14. Vascular reactivity in the brachial artery was evaluated by postischemic hyperemia-induced flow-mediated vasodilatation (FMD) and by vasodilatation following administration of sublingual glyceryl trinitrate (GTN). Forearm skin microcirculation was investigated by laser Doppler perfusion imaging during iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) to assess endothelium-dependent and -independent microvascular vasodilatation, respectively. Fetal growth was measured at study inclusion and birth-weight centile was calculated after delivery.

RESULTS

FMD and GTN-induced vasodilatation were both associated with birth-weight centile. On multivariate analysis (adjusted for brachial artery diameter at rest, blood pressure, maternal age and heart rate), for FMD β = 1.7 (95% CI, 0.06-3.34), r²  = 0.26 and P = 0.042, and for GTN-induced vasodilatation β = 2.6 (95% CI, 0.44-4.68), r²  = 0.15 and P = 0.02. Endothelium-dependent and -independent microvascular reactivity were also associated with birth-weight centile: for ACh β = 7.82 (95% CI, 1.81-13.83), r²  = 0.12 and P = 0.029, and for SNP β = 6.27 (95% CI, 1.20-11.34), r²  = 0.11 and P = 0.016.

CONCLUSION

First-trimester maternal vascular dilatation capacity (rather than endothelial function alone) is associated with fetal growth. These findings were consistent in both the brachial artery and the forearm skin microcirculation. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

High-dose atorvastatin is associated with lower IGF-1 levels in patients with type 1 diabetes

INTRODUCTION

Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 (IGFBP-1) play an important role in vascular health. Many patients with type 1 diabetes are medicated with HMG-CoA reductase inhibitors, statins, in order to prevent vascular complications. Yet little is known about the effect of statins on the IGF-1/IGFBP-1 axis in these patients.

OBJECTIVES

The aim of this study was to evaluate the effect of atorvastatin treatment on IGF-1 and IGFBP-1 with regards to microvascular function.

DESIGN

Twenty patients with type 1 diabetes received either placebo or 80mg atorvastatin for two months in a double-blinded cross-over study. IGF-1 and IGFBP-1 levels were assessed before and after each treatment period. Skin microcirculation was studied using Doppler perfusion imaging during iontophoresis of acetylcholine and sodium nitroprusside to assess endothelium-dependent and endothelium-independent microvascular reactivity, respectively.

RESULTS

Treatment with high-dose atorvastatin was associated with a significant decrease in IGF-1 levels compared to placebo (p<0.05, ANOVA repeated measures), whereas no effect was seen on IGFBP-1 or the IGF-1/IGFBP-1 ratio. These variables did not correlate with measurements of skin microvascular reactivity.

CONCLUSIONS

The study found that treatment with high-dose atorvastatin was associated with reduced IGF-1 levels, which may indicate a potential negative effect on microvascular function and long-term risk of microangiopathy development.

Treatment with high dose of atorvastatin reduces vascular injury in diabetic rats

BACKGROUND

Previous reports showed conflicting results regarding the treatment effects of statin on Diabetes mellitus (DM). We investigated how treatment with high dose of atorvastatin affects the impaired vascular function in diabetic rats.

METHODS

Atorvastatin (80mg/kg/day, oral gavage, 4 weeks) or its vehicle was administered to male control or streptozotocin (STZ)-induced diabetic rats. Aortic segments were used to investigate the vascular reactivity, protein expression of cyclooxygenase-2 (COX-2) and nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) 1 (NOX1) and superoxide anions levels.

RESULTS

Atorvastatin treatment did not affect glycemia levels. In diabetic rats, the vascular reactivity to phenylephrine increased compared with controls and the atorvastatin treatment reduced this response. Removal of the endothelium increased the response to phenylephrine in control rats, but not in the diabetic group. Atorvastatin increased the endothelial modulation in diabetic rats. L-NAME (100μM) increased the reactivity in all groups, but this effect was greater in atorvastatin-treated diabetic rats. Indomethacin (10μM) and NS398 (1μM) decreased the contractile response in diabetic rats and atorvastatin reversed these effects, without changing COX-2 expression. Apocynin (30μM) decreased the phenylephrine response in diabetic rats, which also showed increased NOX1 and superoxide anions; these effects were prevented by atorvastatin treatment.

CONCLUSIONS

The results suggest that treatment with high dose of atorvastatin, independent of glycemia, improves endothelial function in aortas from diabetic rats by reducing the constrictor prostanoids derived from COX-2 and by reducing the oxidative stress by NADPH oxidase, as well as a possible increasing of nitric oxide participation.

The impact of statin therapy on plasma levels of von Willebrand factor antigen. Systematic review and meta-analysis of randomised placebo-controlled trials

Increased plasma levels of von Willebrand factor antigen (vWF:Ag) are associated with high risk of coronary artery disease. The effect of statin therapy on vWF:Ag levels remains uncertain. Therefore the aim of this meta-analysis was to evaluate the effect of statin therapy on vWF:Ag Levels. A systematic multiple-database search was carried out to identify randomized controlled trials (RCTs) that investigated the effect of statins on plasma vWF:Ag levels. Random-effect meta-analysis of 21 treatment arms revealed a significant decrease in plasma vWF:Ag levels following statin therapy (SMD: -0.54, 95 %CI: -0.87, -0.21, p=0.001). In subgroup analyses, the greatest effect was observed with simvastatin (SMD: -1.54, 95 %CI: -2.92, -0.17, p=0.028) and pravastatin (SMD: -0.61, 95 %CI: -1.18, -0.04, p=0.035), but not with fluvastatin (SMD: -0.34, 95 %CI: -0.69, 0.02, p=0.065), atorvastatin (SMD: -0.23, 95 %CI: -0.57, 0.11, p=0.179) and rosuvastatin (SMD: -0.20, 95 % CI: -0.71, 0.30, p=0.431). The lowering effect of statins on plasma vWF:Ag levels was greater in the subset of studies lasting ≥ 12 weeks (SMD: -0.70, 95 %CI: -1.19, -0.22, p=0.005) compared with that of studies lasting < 12 weeks (SMD: -0.34, 95 %CI: -0.67, 0.003, p=0.052). Finally, low-intensity statin therapy was not associated with a significant reduction in vWF:Ag levels (SMD: -0.28, 95 %CI: -0.82, 0.27, p=0.320), but a significant effect was observed in high-intensity statin trials (SMD: -0.66, 95 %CI: -1.07, -0.24, p=0.002). This meta-analysis of available RCTs demonstrates a significant reduction in plasma vWF:Ag levels following statin therapy.

Effects of lipid-lowering treatment on circulating microparticles in patients with diabetes mellitus and chronic kidney disease

BACKGROUND

Elevated levels of circulating microparticles (MPs) may contribute to the high cardiovascular risk in diabetes mellitus (DM) and chronic kidney disease (CKD). Therefore, we investigated the effects of lipid-lowering treatment (LLT) with simvastatin alone (S) or with ezetimibe (S+E) on MPs in DM patients with or without CKD.

METHODS

After a placebo run-in period, 18 DM patients with an estimated glomerular filtration rate (eGFR) of 15-59 mL/min (CKD stages 3-4) (DM-CKD) and 21 DM patients with eGFR >75 mL/min (DM-only) were treated with S and S+E in a randomized, double-blind, crossover study. MPs from platelets, monocytes and endothelial cells (PMPs, MMPs and EMPs), and their expression of phosphatidylserine (PS), P-selectin, CD40 ligand (CD40L) and tissue factor (TF) were measured by flow cytometry.

RESULTS

At baseline, all types of MPs, except TF-positive MMPs, were elevated in DM-CKD compared with DM-only patients. All MPs, regardless of origin and phenotype, were inversely correlated with eGFR. S reduced the expression of P-selectin, TF and CD40L on PMPs and of TF on MMPs in both patient groups. S+E had no further effect. S also reduced total PS-positive procoagulant MPs, PMPs and MMPs in DM-CKD but not in DM-only patients.

CONCLUSIONS

DM patients with CKD stages 3-4 had elevated PMPs, EMPs and MMPs compared with DM patients with normal GFR. Simvastatin reduced procoagulant MPs, MMPs and PMPs in DM-CKD patients, suggesting a beneficial reduction of hypercoagulability in this high-risk patient group. Differences between DM-CKD and DM-only patients were counteracted by LLT.

Extracellular vesicles as new pharmacological targets to treat atherosclerosis

Extracellular vesicles released by most cell types, include apoptotic bodies (ABs), microvesicles (MVs) and exosomes. They play a crucial role in physiology and pathology, contributing to "cell-to-cell" communication by modifying the phenotype and the function of target cells. Thus, extracellular vesicles participate in the key processes of atherosclerosis from endothelial dysfunction, vascular wall inflammation to vascular remodeling. The purpose of this review is to summarize recent findings on extracellular vesicle formation, structure, release and clearance. We focus on the deleterious and beneficial effects of extracellular vesicles in the development of atherosclerosis. The potential role of extracellular vesicles as biomarkers and pharmacological targets, their innate therapeutic capacity, or their use for novel drug delivery devices in atherosclerotic cardiovascular diseases will also be discussed.

Ergocalciferol and microcirculatory function in chronic kidney disease and concomitant vitamin d deficiency: an exploratory, double blind, randomised controlled trial

BACKGROUND AND OBJECTIVES

Vitamin D deficiency and endothelial dysfunction are non-traditional risk factors for cardiovascular events in chronic kidney disease. Previous studies in chronic kidney disease have failed to demonstrate a beneficial effect of vitamin D on arterial stiffness, left ventricular mass and inflammation but none have assessed the effect of vitamin D on microcirculatory endothelial function.

STUDY DESIGN

We conducted a randomised controlled trial of 38 patients with non diabetic chronic kidney disease stage 3-4 and concomitant vitamin D deficiency (<16 ng/dl) who received oral ergocalciferol (50,000 IU weekly for one month followed by 50,000 IU monthly) or placebo over 6 months. The primary outcome was change in microcirculatory function measured by laser Doppler flowmetry after iontophoresis of acetylcholine. Secondary endpoints were tissue advanced glycation end products, sublingual functional capillary density and flow index as well as macrovascular parameters. Parallel in vitro experiments were conducted to determine the effect of ergocalciferol on cultured human endothelial cells.

RESULTS

Twenty patients received ergocalciferol and 18 patients received placebo. After 6 months, there was a significant improvement in the ergocalciferol group in both endothelium dependent microcirculatory vasodilatation after iontophoresis of acetylcholine (p = 0.03) and a reduction in tissue advanced glycation end products (p = 0.03). There were no changes in sublingual microcirculatory parameters. Pulse pressure (p = 0.01) but not aortic pulse wave velocity was reduced. There were no significant changes in bone mineral parameters, blood pressure or left ventricular mass index suggesting that ergocalciferol improved endothelial function independently of these parameters. In parallel experiments, expression of endothelial nitric oxide synthase and activity were increased in human endothelial cells in a dose dependent manner.

CONCLUSIONS

Ergocalciferol improved microcirculatory endothelial function in patients with chronic kidney disease and concomitant vitamin D deficiency. This process may be mediated through enhanced expression and activity of endothelial nitric oxide synthase.

TRIAL REGISTRATION

Clinical trials.gov NCT00882401.

Post-operative endothelial dysfunction assessment using laser Doppler perfusion measurement in cardiac surgery patients

BACKGROUND

Coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) is associated with systemic inflammatory response and endothelial dysfunction. Our hypothesis is that CPB-induced post-operative endothelial dysfunction may be detected using laser Doppler perfusion monitoring (LDPM) in the skin microcirculation.

METHODS

We used LDPM to investigate the subacute effects of the CPB on systemic microvascular reactivity among patients undergoing CABG surgery with CPB. Thirty patients were submitted to the study of skin microcirculation and blood sample collection at baseline (pre-surgery) and at 7 days post-surgical procedure. The skin microcirculation was evaluated by acetylcholine (ACh) and sodium nitroprusside (SNP) iontophoresis, and thermal hyperemia (TH). Plasma levels of nitrite/nitrate were also analyzed, and cytokine profiles were determined using a multiplex system.

RESULTS

On-pump CABG surgery induced a significant reduction of the increased microvascular dermal flux observed after cumulative doses of ACh iontophoresis and after TH. On-pump CABG surgery did not induce any significant changes in the microvascular flux after cumulative doses of SNP. Patients still presented high levels of interleukin (IL)-6, IL-8, and C-reactive protein, and low bioavailability of nitric oxide 7 days after the CABG surgery with CPB.

CONCLUSION

We observed a significant impairment of systemic microvascular endothelial function and well-preserved endothelium-independent vasodilatation in the skin microcirculation of patients 1 week after CABG surgery with CPB. Our results suggest that LDPM is a useful tool for the assessment of on-pump CABG-induced subacute post-operative endothelial dysfunctions.