Relationship between circulating endothelial progenitor cells and endothelial dysfunction in children with type 1 diabetes: a novel paradigm of early atherosclerosis in high-risk young patients

Exposure to air pollution and cardiovascular risk in young children - a pilot project

OBJECTIVE

To examine relationships between traffic-related air pollution (TRAP) and markers of pre-clinical cardiovascular risk in young children.

STUDY DESIGN

We studied a cohort of healthy children ages 2-5 recruited from pediatric primary care sites (n = 122). We obtained child weight, height, blood pressure and hair nicotine levels. A blood sample was obtained for biomarkers of systemic inflammation, oxidation, and prevalence of circulating endothelial progenitor cells. This manuscript represents a secondary analysis. TRAP exposure (particulate levels, nitrogen dioxide, nitrogen oxides, and proximity to major roadways) was assessed using national air pollution data based on child's census tract of residence.

RESULTS

TRAP exposure had significant positive associations with prevalence of two of the three EPC subtypes (CD34 + /CD133 + /CD45- and CD133 + /CD45-) in unadjusted correlations. In a linear regression model, adjusting for sex, age, race, ethnicity, body mass index, parental education, child insurance, and secondhand smoke exposure, one EPC subtype (CD133 + /CD45-) had a positive significant correlation to every TRAP measure. No significant relationships between air pollution and measures of inflammation and oxidation was found.

CONCLUSION

Our findings of the upregulation of EPCs may signal a response to early vascular damage during early childhood due to air pollution exposure.

IMPACT

Traffic-related air pollution (TRAP) - known cardiovascular risk factor during adulthood Current pilot study in very young children shows upregulation of cells which protect the endothelial lining of blood vessels (endothelial progenitor cells, EPCs) Upregulation of EPCs aligns with other cardiovascular risks during childhood (obesity, prematurity, type 1 diabetes) Demonstrated with TRAP exposure lower than EPA threshold Response to air pollution may be protective of cardiovascular damage during early childhood.

Alterations in Stem Cell Populations in IGF-1 Deficient Pediatric Patients Subjected to Mecasermin (Increlex) Treatment

Pathway involving insulin-like growth factor 1 (IGF-1) plays significant role in growth and development. Crucial role of IGF-1 was discovered inter alia through studies involving deficient patients with short stature, including Laron syndrome individuals. Noteworthy, despite disturbances in proper growth, elevated values for selected stem cell populations were found in IGF-1 deficient patients. Therefore, here we focused on investigating role of these cells-very small embryonic-like (VSEL) and hematopoietic stem cells (HSC), in the pathology. For the first time we performed long-term observation of these populations in response to rhIGF-1 (mecasermin) therapy. Enrolled pediatric subjects with IGF-1 deficiency syndrome were monitored for 4-5 years of rhIGF-1 treatment. Selected stem cells were analyzed in peripheral blood flow cytometrically, together with chemoattractant SDF-1 using immunoenzymatic method. Patients' data were collected for correlation of experimental results with clinical outcome. IGF-1 deficient patients were found to demonstrate initially higher levels of VSEL and HSC compared to healthy controls, with their gradual decrease in response to therapy. These changes were significantly associated with SDF-1 plasma levels. Correlations of VSEL and HSC were also reported in reference to growth-related parameters, and IGF-1 and IGFBP3 values. Noteworthy, rhIGF-1 was shown to efficiently induce development of Laron patients achieving at least proper rate of growth (compared to healthy group) in 80% of subjects. In conclusion, here we provided novel insight into stem cells participation in IGF-1 deficiency in patients. Thus, we demonstrated basis for future studies in context of stem cells and IGF-1 role in growth disturbances.

Vascular and Myocardial Function in Young People with Type 1 Diabetes Mellitus: Insulin Pump Therapy Versus Multiple Daily Injections Insulin Regimen

INTRODUCTION

Multiple daily injections (MDI) and continuous subcutaneous insulin infusion (CSII) are two modalities of treating type 1 diabetes mellitus (T1DM). The benefits of CSII on long-term metabolic control and outcomes compared to those of MDI are still debated. We investigated both vascular function and myocardial performance in T1DM adolescents on MDI or CSII treatment.

METHODS

One hundred twenty-three T1DM subjects (mean age 14.16±2.55 years), 63 on MDI regimen, 60 on CSII, and 57 controls were enrolled. Anthropometric and biochemical characteristics were evaluated. Ultrasound assessments of carotid intima-media thickness (cIMT), flow-mediated dilatation of brachial artery, anteroposterior diameter of the infrarenal abdominal aorta (APAO), and transthoracic echocardiography were performed.

RESULTS

T1DM subjects on the CSII regimen showed better glycemic control than those on MDI, expressed as glycated haemoglobin (HbA1c). c-IMT and APAO were higher in MDI than CSII patients (0.61±0.11 mm vs. 0.56±0.07 mm, p=0.04; 13.61±3.29 mm vs. 11.65±1.84 mm, p=0.01, respectively). Left and right Tei index and left E/e' ratio were higher in MDI than CSII subjects (0.82±0.40 vs. 0.52±0.19, p=0.002; 0.86±0.41 vs. 0.64±0.1, p=0.02; 5.89±2.0 vs. 4.73±1.59, p=0.02, respectively). Multiple regression analyses showed that glucose level, HbA1c and diabetes onset were significantly related to vascular and echocardiographic parameters in MDI and CSII patients.

CONCLUSIONS

CSII regimen in T1DM adolescents improves glycemic control and seems to ameliorate endothelial function and global myocardial performance as compared to MDI therapy.

Increased circulating endothelial progenitor cells (EPCs) in prepubertal children born prematurely: a possible link between prematurity and cardiovascular risk

BACKGROUND

Endothelial progenitor cells (EPCs) ensure vascular integrity and neovascularization. No studies have investigated EPCs in preterm-born children beyond infancy.

METHODS

One hundred and thirty-six prepubertal children were enrolled: 63 preterm and 73 born at term (controls). Circulating CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs were measured in preterm-born children compared to controls. Body mass index (BMI), waist-to-hip ratio (WHR), neck circumference, systolic and diastolic blood pressure (SBP and DBP, respectively), fasting glucose, insulin, lipid profile, common carotid and abdominal aortic intima-media thickness (cIMT and aIMT, respectively), endothelium-dependent brachial artery flow-mediated dilation (FMD), and echocardiographic parameters were also assessed.

RESULTS

Circulating CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs were significantly higher in preterm-born children compared to controls (p < 0.001 and p < 0.001, respectively). In total study population and in the preterm-born group, EPCs were significantly lower in children born to mothers with gestational diabetes compared to non-diabetic mothers. Prematurity was associated with higher WHR, neck circumference, SBP, DBP, cIMT, aIMT, mean pressure, and velocity of pulmonary artery; the peak velocity of the brachial artery was significantly lower in children born prematurely. In multiple regression analysis, preterm birth and maternal gestational diabetes were recognized as independent predictors of EPCs.

CONCLUSIONS

Circulating EPCs were increased in prepubertal preterm-born children in comparison with peers born full-term. Maternal gestational diabetes was associated with a decrease in EPCs.

IMPACT

Mounting evidence supports the adverse effect of prematurity on cardiovascular health. However, the underlying mechanisms that could lead to endothelial dysfunction in preterm-born individuals are not fully understood. Endothelial progenitor cells (EPCs) ensure vascular integrity, normal endothelial function and neovascularization. No studies have investigated the EPCs counts in peripheral blood beyond infancy in children born prematurely. Circulating EPCs were significantly higher in preterm-born prepubertal children compared to controls, thus indicating that prematurity is possibly associated with endothelial damage. In total study population and in the preterm-born group, maternal gestational diabetes was associated with decreased EPCs concentrations.

Decreased Flow-Mediated Dilatation in Children With Type 1 Diabetes: A Systematic Review and Meta-Analysis

Type 1 diabetes (T1DM) is a strong risk factor for the development of cardiovascular disease. Flow-mediated dilatation (FMD) is an early noninvasive marker of endothelial function and it predicts future cardiovascular disease. However, the changes in FMD among T1DM children are still controversial. The present meta-analysis aimed to investigate whether FMD is impaired in children with T1DM. PubMed, EMBASE, Cochrane library, and Web of Science were searched for studies comparing FMD in children with T1DM and healthy controls. The Newcastle-Ottawa quality assessment scale for case-control studies was used to assess study quality. Data were pooled using a random effects models to obtain the weighted mean differences (WMD) in FMD and 95% CIs. Overall, 19 studies with 1245 patients and 872 healthy controls were included in this meta-analysis. Children with T1DM had significantly lower FMDs compared with healthy controls (WMD: -2.58; 95% CI: -3.36 to -1.81; P < .001). Meta-regression analysis revealed that low-density lipoprotein cholesterol levels impacted the observed difference in FMD between T1DM and healthy children. This meta-analysis showed that T1DM children have impaired endothelial function, which indicates they are at higher risk of developing cardiovascular disease in later life.

Does Hashimoto's Thyroiditis Increase the Risk of Cardiovascular Disease in Young Type 1 Diabetic Patients?

Background: Immunological and hormonal disorders have undoubted influence on the development of atherosclerotic process. Autoimmune diseases accompanying type 1 diabetes (T1D) may additionally accelerate atherosclerosis progression and increase the risk of cardiovascular events in the future. The influence of subclinical hypothyroidism on the cardiovascular system, in particular, has recently aroused great interest. The aim of our study was to assess intima-media thickness (cIMT) of common carotid arteries and the occurrence of classical atherosclerosis risk factors together with selected new biomarkers of cardiovascular diseases in young patients with type 1 diabetes mellitus coexisting with Hashimoto's disease (HD). Patients and Methods: The study included 50 adolescents and young adults with T1D with mean age 17.1 ± 3 years, with mean diabetes duration of 10.5 ± 3.3 years, including 20 patients with diagnosed HD: T1D and HD(+), and 30 patients with no additional diseases: T1D and HD(-). Twenty-two healthy, age-matched volunteers formed control group (C). We analyzed mean HbA₁c value from all years of disease, BMI, blood pressure, lipids, new biomarkers of atherosclerosis (hsCRP, adiponectin, myeloperoxidase, NT-proBNP peptide, vitamin D), and cIMT of common carotid arteries. Results: In the group of patients with T1D and HD(+), significantly higher BMI was found: 23.3 ± 4.4 vs. 21.28 ± 2.9 in group HD(-) and 19.65 ± 2.4 kg/m² in group C (p = 0.003), and higher waist circumference: 79 ± 10.9 vs. 75.10 ± 7.6 in group HD(-) vs. 69.0 ± 7.4 cm in group C (p < 0.001). The mean value of HbA₁c was higher in group T1D and HD(+): 8.8% than in group HD(-): 8.1% (p = 0.04). Significantly higher concentration of hsCRP and lower vitamin D were observed in T1D and HD(+) in comparison to T1D and HD(-) and the control group. The IMT index in the HD(+) group was 0.46 ± 0.05 mm and was comparable to the HD(-) group but significantly higher than in healthy controls: 0.41 ± 0.03 mm (P < 0.05). Conclusions: Young patients with type 1 diabetes mellitus and with coexisting Hashimoto's thyroiditis have a higher BMI, a higher waist circumference, and a higher HbA₁c value, which altogether may cause faster development of macroangiopathy in the near future. Additional risk for cardiovascular disease may result from low vitamin D and increased hsCRP concentration in this group of patients. Coexistence of Hashimoto's thyroiditis did not significantly affect the cIMT value in the studied population.

Early Endothelial Dysfunction in Type 1 Diabetes Is Accompanied by an Impairment of Vascular Smooth Muscle Function: A Meta-Analysis

Background: A large yet heterogeneous body of literature exists suggesting that endothelial dysfunction appears early in type 1 diabetes, due to hyperglycemia-induced oxidative stress. The latter may also affect vascular smooth muscles (VSM) function, a layer albeit less frequently considered in that pathology. This meta-analysis aims at evaluating the extent, and the contributing risk factors, of early endothelial dysfunction, and of the possible concomitant VSM dysfunction, in type 1 diabetes. Methods: PubMed, Web of Sciences, Cochrane Library databases were screened from their respective inceptions until October 2019. We included studies comparing vasodilatory capacity depending or not on endothelium (i.e., endothelial function or VSM function, respectively) in patients with uncomplicated type 1 diabetes and healthy controls. Results: Fifty-eight articles studying endothelium-dependent function, among which 21 studies also assessed VSM, were included. Global analyses revealed an impairment of standardized mean difference (SMD) (Cohen's d) of endothelial function: -0.61 (95% CI: -0.79, -0.44) but also of VSM SMD: -0.32 (95% CI: -0.57, -0.07). The type of stimuli used (i.e., exercise, occlusion-reperfusion, pharmacological substances, heat) did not influence the impairment of the vasodilatory capacity. Endothelial dysfunction appeared more pronounced within macrovascular than microvascular beds. The latter was particularly altered in cases of poor glycemic control [HbA_1c > 67 mmol/mol (8.3%)]. Conclusions: This meta-analysis not only corroborates the presence of an early impairment of endothelial function, even in response to physiological stimuli like exercise, but also highlights a VSM dysfunction in children and adults with type 1 diabetes. Endothelial dysfunction seems to be more pronounced in large than small vessels, fostering the debate on their relative temporal appearance.

Platelet-Rich Plasma with Endothelial Progenitor Cells Accelerates Diabetic Wound Healing in Rats by Upregulating the Notch1 Signaling Pathway

Diabetic wounds, as a kind of refractory wound, are very difficult to heal. Both endothelial progenitor cell (EPC) transplantation and platelet-rich plasma (PRP) can improve diabetic wound healing to some extent. However, PRP application cannot provide reparative cells, while EPC transplantation cannot replenish the required growth factors for wound healing. Thus, when applied alone, neither of these factors is sufficient for effective wound healing. Furthermore, the proliferation, differentiation, and fate of the transplanted EPCs are not well known. Therefore, in this study, we examined the efficacy of combined PRP application with EPC transplantation in diabetic wound healing. Our results indicated that PRP application improved EPC proliferation and migration. The Notch signaling pathway plays a key role in the regulation of the proliferation and differentiation of stem cells and angiogenesis in wound healing. The application of PRP upregulated the Notch pathway-related gene and protein expression in EPCs. Furthermore, experiments with shNotch1-transfected EPCs indicated that PRP enhanced the function of EPCs by upregulating the Notch1 signaling pathway. In vivo studies further indicated that the combination of PRP and EPC transplantation increased neovascularization, reduced wound size, and improved healing in rat wound models. Thus, PRP application can provide the necessary growth factors for wound healing, while EPC transplantation offers the required cells, indicating that the combination of both is a potent novel approach for treating diabetic wounds.

Supplementary Nitric Oxide Donors and Exercise as Potential Means to Improve Vascular Health in People with Type 1 Diabetes: Yes to NO?

Type 1 diabetes (T1D) is associated with a greater occurrence of cardiovascular pathologies. Vascular dysfunction has been shown at the level of the endothelial layers and failure to maintain a continuous pool of circulating nitric oxide (NO) has been implicated in the progression of poor vascular health. Biochemically, NO can be produced via two distinct yet inter-related pathways that involve an upregulation in the enzymatic activity of nitric oxide synthase (NOS). These pathways can be split into an endogenous oxygen-dependent pathway i.e., the catabolism of the amino acid L-arginine to L-citrulline concurrently yielding NO in the process, and an exogenous oxygen-independent one i.e., the conversion of exogenous inorganic nitrate to nitrite and subsequently NO in a stepwise fashion. Although a body of research has explored the vascular responses to exercise and/or compounds known to stimulate NOS and subsequently NO production, there is little research applying these findings to individuals with T1D, for whom preventative strategies that alleviate or at least temper vascular pathologies are critical foci for long-term risk mitigation. This review addresses the proposed mechanisms responsible for vascular dysfunction, before exploring the potential mechanisms by which exercise, and two supplementary NO donors may provide vascular benefits in T1D.

Circulating Endothelial Cells, Circulating Endothelial Progenitor Cells, and Circulating Microparticles in Type 1 Diabetes Mellitus

Background and Aim:

Hyperglycemia in type 1 diabetes (T1D) is accompanied by endothelial cell dysfunction which is known to contribute to the pathogenesis of cardiovascular disorders. The aim of the current study was to explore the profile of circulating endothelial progenitor cells (EPCs), circulating endothelial cells (CECs), endothelial and platelet derived micropaticles (EMPs, PMPs) and total microparticles (TMPs), in T1D children in relation to each other and to the metabolic disorders accompanying T1D.

Patients and Methods:

Thirty T1D patients and 20 age and sex matched healthy volunteers were assessed for HbA1c level and lipid profile. Quantification of CECs, EPCs, TMPs, EMPs and PMPs was done by flow cytometry.

Results:

The mean levels of EMPs, PMPs, TMPs and CECs were significantly higher in diabetic children compared to controls. Meanwhile, the levels of EPCs were significantly lower in diabetic children compared to controls. Both PMPs and CECs showed the highest significant differences between patients and controls and their levels were directly related to HbA1c, total cholesterol, LDL and triglycerides. A moderate correlation was observed between the frequency of PMPs and CECs. EPCs revealed negative correlations with both LDL and triglycerides. TMPs were only related to LDL, while EMPs were only related to HbA1c.

Conclusion:

Although there is disturbance in the levels of EMPs, PMPs, TMPs, CECs and EPCs in type 1 diabetic children compared to the controls, only the levels of PMPs and CECs were closely affected by the poor glycemic control and dyslipidemia occurring in T1D; thus may contribute to a higher risk of cardiovascular diseases.

Detrimental Impact of Low Birth Weight on Circulating Number and Functional Capacity of Endothelial Progenitor Cells in Healthy Children: Role of Angiogenic Factors

OBJECTIVE

To provide a comprehensive assessment of the relationship of birth weight with both endothelial progenitor cell function and angiogenic factors in children.

STUDY DESIGN

Anthropometric measures, biochemical profile, endothelial progenitor cell number, endothelial progenitor cell colony-forming units, vascular endothelial growth factor-A, and nitric oxide plasma levels of 58 children aged 7-11 years were determined.

RESULTS

A positive correlation was observed between birth weight and circulating endothelial progenitor cell number (r= 0.461; P= .001), endothelial progenitor cell colony-forming units (r= 0.512; P < .001), vascular endothelial growth factor-A (r= 0.407; P= .002), and nitric oxide (r= 0.547; P < .001) levels, whereas the adjustment for prematurity, family history of cardiovascular disease, and systolic blood pressure levels did not modify these associations.

CONCLUSION

Low birth weight was associated with a decrease in the circulating/functional capacity of endothelial progenitor cells among healthy children, independent of traditional cardiovascular risk factors. This detrimental impact was accompanied by lower circulating levels of angiogenic factors.

Endothelial Cell Metabolism

Endothelial cells (ECs) are more than inert blood vessel lining material. Instead, they are active players in the formation of new blood vessels (angiogenesis) both in health and (life-threatening) diseases. Recently, a new concept arose by which EC metabolism drives angiogenesis in parallel to well-established angiogenic growth factors (e.g., vascular endothelial growth factor). 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3-driven glycolysis generates energy to sustain competitive behavior of the ECs at the tip of a growing vessel sprout, whereas carnitine palmitoyltransferase 1a-controlled fatty acid oxidation regulates nucleotide synthesis and proliferation of ECs in the stalk of the sprout. To maintain vascular homeostasis, ECs rely on an intricate metabolic wiring characterized by intracellular compartmentalization, use metabolites for epigenetic regulation of EC subtype differentiation, crosstalk through metabolite release with other cell types, and exhibit EC subtype-specific metabolic traits. Importantly, maladaptation of EC metabolism contributes to vascular disorders, through EC dysfunction or excess angiogenesis, and presents new opportunities for anti-angiogenic strategies. Here we provide a comprehensive overview of established as well as newly uncovered aspects of EC metabolism.

Modifiable Risk Factors for Cardiovascular Disease in Children with Type 1 Diabetes: Can Early Intervention Prevent Future Cardiovascular Events?

PURPOSE OF REVIEW

Patients with type 1 diabetes have increased risk for cardiovascular disease. The purpose of this review is to examine the following: i) current evidence for subclinical cardiovascular disease (CVD) in children with type 1 diabetes (T1DM) ii) known modifiable risk factors for CVD and their relationship to subclinical CVD in this population iii) studies that have addressed these risk factors in order to improve CVD outcomes in children with T1DM RECENT FINDINGS: Subclinical CVD presents in children as increased carotid intima-media thickness, increased arterial stiffness, and endothelial and myocardial dysfunction. Modifiable risk factors for CVD include hyperglycemia, hyperlipidemia, obesity, hypertension, depression, and autonomic dysfunction. Very few randomized controlled studies have been done in children with T1DM to examine how modification of these risk factors can affect their CVD. Children with T1DM have subclinical CVD and multiple modifiable risk factors for CVD. More research is needed to define how modification of these factors affects the progression of CVD.

Circulating Endothelial Progenitor Cells in Type 1 Diabetic Patients: Relation with Patients' Age and Disease Duration

OBJECTIVES

Circulating endothelial progenitor cells (cEPCs) have been reported to be dysfunctional in diabetes mellitus (DM) patients, accounting for the vascular damage and the ensuing high risk for cardiovascular disease (CVD) characteristic of this disease. The aim of the present study was to evaluate the number of circulating cEPCs in type 1 DM (T1DM) patients, without clinical vascular damage, of different ages and with different disease duration.

METHODS

An observational, clinical-based prospective study was performed on T1DM patients enrolled in two clinical centers. cEPCs were determined by flow cytometry, determining the number of CD34/CD133/VEGFR2-positive cells within peripheral blood mononuclear cells (PBMCs).

RESULTS

The number of cEPCs was lower in adult T1DM patients, whilst higher in childhood/young patients, compared to controls of the same age range. When patients were grouped into two age groups (≥ or <20 years) (and categorized on the basis of the duration of the disease), the number of cEPCs in young (<20 years) patients was higher compared with older subjects, regardless of disease duration. A subset of patients with very high cEPCs was identified in the <20 years group.

CONCLUSION

There is an association between the number of cEPCs and patients' age: childhood/young T1DM patients have significantly higher levels of cEPCs, respect to adult T1DM patients. Such difference is maintained also when the disease lasts for more than 10 years. The very high levels of cEPCs, identified in a subset of childhood/young patients, might protect vessels against endothelial dysfunction and damage. Such protection would be less operative in older subjects, endowed with lower cEPC numbers, in which complications are known to develop more easily.

Effective Mobilization of Very Small Embryonic-Like Stem Cells and Hematopoietic Stem/Progenitor Cells but Not Endothelial Progenitor Cells by Follicle-Stimulating Hormone Therapy

Recently, murine hematopoietic progenitor stem cells (HSCs) and very small embryonic-like stem cells (VSELs) were demonstrated to express receptors for sex hormones including follicle-stimulating hormone (FSH). This raised the question of whether FSH therapy at clinically applied doses can mobilize stem/progenitor cells in humans. Here we assessed frequencies of VSELs (referred to as Lin⁻CD235a⁻CD45⁻CD133⁺ cells), HSPCs (referred to as Lin⁻CD235a⁻CD45⁺CD133⁺ cells), and endothelial progenitor cells (EPCs, identified as CD34⁺CD144⁺, CD34⁺CD133⁺, and CD34⁺CD309⁺CD133⁺ cells) in fifteen female patients subjected to the FSH therapy. We demonstrated that FSH therapy resulted in statistically significant enhancement in peripheral blood (PB) number of both VSELs and HSPCs. In contrast, the pattern of responses of EPCs delineated by different cell phenotypes was not uniform and we did not observe any significant changes in EPC numbers following hormone therapy. Our data indicate that FSH therapy mobilizes VSELs and HSPCs into peripheral blood that on one hand supports their developmental origin from germ lineage, and on the other hand FSH can become a promising candidate tool for mobilizing HSCs and stem cells with VSEL phenotype in clinical settings.

Effects of acute exercise on circulating endothelial and progenitor cells in children and adolescents with juvenile idiopathic arthritis and healthy controls: a pilot study

BACKGROUND

Youth with juvenile idiopathic arthritis (JIA) may be at risk of poor cardiovascular health. Circulating endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) are markers of cardiovascular repair and damage, respectively, and respond to exercise. The objectives of this study were to compare resting levels of EPCs and CECs in JIA and controls, and to assess the effects of distinct types of exercise on EPCs and CECs in JIA and controls.

METHODS

Seven youth with JIA and six controls completed 3 visits. First, aerobic fitness was assessed. Participants then performed either moderate intensity, continuous exercise (MICE) or high intensity, intermittent exercise (HIIE) on separate days. Blood samples were collected at the beginning (REST), mid-point (MID) and end of exercise (POST) for determination of EPCs (CD31(+)CD34(bright)CD45(dim)CD133(+)) and CECs (CD31(bright)CD34(+)CD45(-)CD133(-)) by flow cytometry. Between group differences in EPCs and CECs were examined using two-way ANOVA, followed by Tukey's HSD post hoc, where appropriate. Statistical significance set at p ≤ 0.05.

RESULTS

Both EPCs and CECs were similar between groups at REST (p = 0.18-0.94). During MICE, EPCs remained unchanged in JIA (p = 0.95) but increased significantly at POST in controls (REST: 0.91 ± 0.55 × 10(6) cells/L vs. POST: 1.53 ± 0.36 × 10(6) cells/L, p = 0.04). Compared with controls, lower levels of EPCs were observed in JIA at MID (0.48 ± 0.50 × 10(6) cells/L vs. 1.10 ± 0.39 × 10(6) cells/L, p = 0.01) and POST (0.38 ± 0.34 × 10(6) cells/L vs. 1.53 ± 0.36 × 10(6) cells/L, p < 0.001) during MICE. No changes were detected in CECs with MICE in JIA and controls (p = 0.69). Neither EPCs nor CECs were modified with HIIE (p = 0.28-0.69).

CONCLUSION

Youth with JIA demonstrated a blunted EPC response to MICE when compared with controls. Future work should examine factors that may increase or normalize EPC mobilization in JIA.

Circulating endothelial cells in children: role of fitness, activity, and adiposity

PURPOSE

Circulating endothelial cells (CEC) are thought to be useful biomarkers of endothelial dysfunction and overall cardiovascular health. The extent to which CEC are influenced by fitness, physical activity, and adiposity in youth remains unknown, as they have seldom been examined in the pediatric population. This study assessed resting levels of CEC in boys and girls of different chronological and biological age and explored the relationship between these cells and aerobic fitness, physical activity, and adiposity.

METHODS

Seventy-five children (39 males; median [interquartile range], age = 14.4 [5.8]) completed two study visits. During the first visit, basic anthropometric data were collected and biological age was calculated. Peak mechanical power (Wpeak) was determined using the McMaster All-Out Continuous cycling test. Participants then wore an accelerometer over a 7-d period to assess habitual levels of moderate-to-vigorous physical activity. During visit 2, percent body fat (%BF) was assessed by dual-energy x-ray absorptiometry. A fasted blood sample was also collected from which concentrations of CEC, identified as CD31CD34CD45CD133, were quantified by flow cytometry.

RESULTS

No differences were seen in CEC by sex, chronological age, or biological age. The median (interquartile range) CEC concentration was 32.3 × 10 (63.0 × 10), representing 1.3% (2.7%) of collected peripheral blood mononuclear cells. CEC concentration was associated with Wpeak normalized to lean body mass (r = 0.36, P < 0.01) and time spent in moderate-to-vigorous physical activity (r = -0.27, P = 0.02). No relationship was observed between CEC and %BF.

CONCLUSION

Healthy children demonstrate relatively low concentrations of CECs. Because CEC represent a population of mature endothelial cells shed from the intima after irreversible damage, they may be more reflective of recent physical activity levels rather than fitness or level of adiposity.

Enhancing endothelial progenitor cell for clinical use

Circulating endothelial progenitor cells (EPCs) have been demonstrated to correlate negatively with vascular endothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases.

Aortic Intima-Media Thickness as an Early Marker of Atherosclerosis in Children With Inflammatory Bowel Disease

OBJECTIVES

The aims of this study were to determine the presence of endothelial dysfunction by measuring aortic intima-media thickness (aIMT) and carotid intima-media thickness (cIMT) and to evaluate the role of traditional risk factors for premature atherosclerosis in children with inflammatory bowel disease (IBD).

METHODS

Thirty-four children with IBD (25 Crohn disease [CD] and 9 ulcerative colitis [UC]; mean age 11.1 years) and 27 healthy subjects matched for sex and age were enrolled. In all of the patients, demographic characteristics and risk factors for atherosclerosis (age, sex, body mass index, blood pressure, dyslipidemia, active and passive smoking, and family history for cardiovascular diseases), CD and UC clinical activity scores, and inflammatory markers were evaluated. aIMT and cIMT were measured by high-resolution B-mode ultrasound.

RESULTS

aIMT was significantly higher in patients than in controls (P < 0.0005). No significant differences were found for cIMT, although the carotid thickness was higher in patients with IBD than in healthy subjects. At a univariate analysis, inflammatory markers levels and tobacco smoking exposure were significantly related to higher aIMT values, whereas in a multivariate regression model, the inflammatory status was the only independent variable correlated with high aIMT.

CONCLUSIONS

aIMT is an earlier marker of preclinical atherosclerosis than cIMT in young children with active IBD. The inflammatory status and the smoking exposure are significantly correlated with the premature endothelial dysfunction. These data emphasize the importance of controlling the chronic intestinal inflammation and endorsing smoke-free environments for children and adolescents with IBD.

Endothelial progenitor cell levels in juvenile idiopathic arthritis patients: effects of anti-inflammatory therapies

BACKGROUND

Juvenile idiopathic arthritis (JIA), similarly to other arthritides, can be associated with damage of endothelial layer of which structure and function is dependent on reparative properties of endothelial progenitor cells (EPC). To date, it remained unknown whether EPC numbers are altered in young JIA patients and whether on-going anti-inflammatory therapies could exert positive effects on these progenitor cells.

METHODS

We performed a quantitative analysis of EPC numbers in 25 patients diagnosed with JIA according to International League of Associations for Rheumatism (ILAR) criteria [age 11.50 (7.50-15.00) years] in a broad context of inflammatory and cardiovascular parameters as well as different types of anti-inflammatory treatments. 11 healthy children [age 13.00 (11.00-14.00) years] were recruited as a control group.

RESULTS

We demonstrated that EPC numbers were similar in JIA patients and control subjects (0.02% vs. 0.05%, respectively, p = 0.37). EPC levels in JIA patients were negatively correlated with index of insulin resistance (rho = -0.458, p = 0.021), endogenous insulin (rho = -0.472, p = 0.017), triglyceride (rho = -0.438, p = 0.029) and TNF-alpha levels (rho = -0.446, p = 0.026). Notably, glucocorticoid (GC) therapy, was associated with detection of decreased EPC levels in JIA patients (p = 0.023). In contrast, methothrexate (MTX) and etanercept therapy in JIA patients did not affect EPC levels (p = 0.92 and p = 0.08, respectively).

CONCLUSIONS

We found that EPC numbers are maintained at normal levels in JIA patients and are not enhanced by disease-specific anti-inflammatory treatments.

Adolescents and young adults with type 1 diabetes display a high prevalence of endothelial dysfunction

AIM

Little is known about endothelial function in adolescents with type 1 diabetes, and we evaluated endothelial dysfunction, using reactive hyperaemia peripheral arterial tonometry (RH-PAT).

METHODS

This prospective, observational, 1-year study focused on 73 adolescents with type 1 diabetes, using multiple daily injections or continuous subcutaneous insulin infusion. The subjects were assessed using RH-PAT, body mass index, blood pressure, fasting lipid profile, glycated haemoglobin, insulin requirements and hours of physical exercise per week.

RESULTS

Endothelial dysfunction was observed in 56 patients (76.7%), with lower mean RH-PAT scores (1.26 ± 0.22 versus 2.24 ± 0.48, p < 0.0001) and higher glycated haemoglobin values at baseline (8.27 ± 1.24% versus 7.37 ± 0.54%, p = 0.006) and as a mean of the whole period since diagnosis (8.25 ± 1.22% versus 7.72 ± 0.82%, p = 0.034). A higher percentage of patients with endothelial dysfunction showed abnormal cardiac autonomic tests (p = 0.02) and were more sedentary, exercising <4 hours a week, than patients with normal endothelial function. After follow-up in 64/73 patients, we observed endothelial dysfunction in 81.8% of patients, despite a modest improvement in glycated haemoglobin.

CONCLUSION

Adolescents with type 1 diabetes displayed evidence of endothelial dysfunction. Good metabolic control (glycated haemoglobin ≤7.5%, 58 mmol/mol) and regular physical activity of at least 4 h a week might be protective.

Inflammation in childhood type 1 diabetes; influence of glycemic control

OBJECTIVE

Patients with type 1 diabetes have increased mortality from cardiovascular disease, and inflammation is important in the development of atherosclerosis. Our aim was to evaluate the extent of inflammation and the influence of glycemic control in the early phases of atherosclerosis in childhood type 1 diabetes.

MATERIALS AND METHODS

A population based cohort representative of all children with type 1 diabetes in Norway was studied. Diabetes patients (n = 314) were compared to healthy controls (n = 120), aged 8-18 years. Circulating levels of VCAM-1, ICAM-1, E-selectin, P-selectin, TNFα, IL-6, CRP, MCP-1, IL-18, MMP-9 and TIMP-1 were measured by immunoassays.

RESULTS

The diabetes patients had a mean age of 13.7 (SD = 2.8) years, disease duration of 5.5 (SD = 3.4) years and HbA1c of 8.4 (SD = 1.2) % (68 mmol/mol, SD = 13.1). The levels of most of the measured markers were significantly increased in the diabetes group compared to controls. In the diabetes group, all except MCP-1 and MMP-9 were significantly correlated to HbA1c, albeit the relation to VCAM-1 was inverse. There were no significant correlations in the control group. The measured markers were only to a limited degree associated with traditional risk factors. CRP showed the most pronounced difference between diabetes patients and controls and the strongest correlation with HbA1c. The use of oral contraceptives profoundly increased CRP levels, independent of the presence of diabetes.

CONCLUSIONS

Our results indicate that inflammation may play an important role in the accelerated atherosclerosis in early type 1 diabetes, and that this process seems primarily driven by hyperglycemia.

Vascular Dysfunction in Patients With Young β-Thalassemia

We aimed to study the endothelial dysfunction among children and adolescents with transfusion-dependent β-thalassemia using von Willebrand factor antigen (VWF:Ag) and flow cytometric analysis of circulating CD144+ endothelial microparticles (EMPs) and endothelial progenitor cells (CD34+VEGFR2+) and assess their relation to iron overload, erythropoietin and chelation therapy as well as echocardiographic parameters and carotid intima–media thickness. The VWF:Ag, EMPs, and CD34+VEGFR2+ cells were significantly higher among patients with β-thalassemia than controls ( P < .001). The type of chelation and patients’ compliance did not influence the results. No significant correlations were found between the studied vascular markers. Patients with evident heart disease had higher VWF: Ag, EMPs, and CD34+VEGFR2+ cells than those without. Carotid intima–media thickness was increased among patients but not correlated with vascular markers. We suggest that procoagulant EMPs and VWF: Ag are involved in cardiovascular complications in patients with young β-thalassemia. CD34+VEGFR2+ cells were further increased in response to tissue injury contributing to reendothelialization and neovascularization.

MAS-mediated antioxidant effects restore the functionality of angiotensin converting enzyme 2-angiotensin-(1-7)-MAS axis in diabetic rat carotid

We hypothesized that endothelial AT₁-activated NAD(P)H oxidase-driven generation of reactive oxygen species during type I-diabetes impairs carotid ACE2-angiotensin-(1–7)-Mas axis functionality, which accounts for the impaired carotid flow in diabetic rats. We also hypothesized that angiotensin-(1–7) chronic treatment of diabetic rats restores carotid ACE2-angiotensin-(1–7)-Mas axis functionality and carotid flow. Relaxant curves for angiotensin II or angiotensin-(1–7) were obtained in carotid from streptozotocin-induced diabetic rats. Superoxide or hydrogen peroxide levels were measured by flow cytometry in carotid endothelial cells. Carotid flow was also determined. We found that endothelial AT₁-activated NAD(P)H oxidase-driven generation of superoxide and hydrogen peroxide in diabetic rat carotid impairs ACE2-angiotensin-(1–7)-Mas axis functionality, which reduces carotid flow. In this mechanism, hydrogen peroxide derived from superoxide dismutation inhibits ACE2 activity in generating angiotensin-(1–7) seemingly by activating I_Cl,SWELL, while superoxide inhibits the nitrergic Mas-mediated vasorelaxation evoked by angiotensin-(1–7). Angiotensin-(1–7) treatment of diabetic rats restored carotid ACE2-angiotensin-(1–7)-Mas axis functionality by triggering a positive feedback played by endothelial Mas receptors, that blunts endothelial AT₁-activated NAD(P)H oxidase-driven generation of reactive oxygen species. Mas-mediated antioxidant effects also restored diabetic rat carotid flow, pointing to the contribution of ACE2-angiotensin-(1–7)-Mas axis in maintaining carotid flow.

Longitudinal evaluation of endothelial function in children and adolescents with type 1 diabetes mellitus: a long-term follow-up study

BACKGROUND

Type 1 diabetes (T1DM) predisposes to cardiovascular disease, increasing the risk to develop atherosclerosis. In the pediatric population, the cardiovascular risk may be evaluated examining endothelial function by a non-invasive ultrasound technique, namely flow-mediated dilation (FMD) of the brachial artery. The aims of this study were the longitudinal evaluation of the potential change in the endothelium-dependent vasomotor function in children and adolescents with T1DM and the identification of clinical and laboratory data correlated to modifications.

METHODS

We studied 39 T1DM patients (20 girls and 19 boys; aged 11.2 ± 3.72 years). FMD and blood samples were obtained from all patients at baseline (time 0) and after a follow up of at least 1 year (time 1). FMD was also evaluated in 45 healthy controls (22 boys, 23 girls) aged 10.2 ± 3.05 years.

RESULTS

At time 0, 43.6% of T1DM patients presented an impaired FMD. FMD at time 1 revealed a dramatic impairment of endothelial function: altered FMD values were shown in 61.5% of patients and it got worse in 74.3% of them. Longitudinally, boys had a greater impairment of FMD than girls. At baseline, multivariate analysis identified only sex as significant predictor of FMD (β = 0.470, P = 0.029).

CONCLUSIONS

Because endothelial dysfunction appears earlier in diabetic children, they are at higher risk to develop atherosclerosis. Our results suggest the usefulness of FMD as a tool to stratify pediatric T1DM patients according to their cardiovascular risk and to follow them up longitudinally.

Decreased CD127 expression on CD4+ T-cells and elevated frequencies of CD4+CD25+CD127- T-cells in children with long-lasting type 1 diabetes

Pathobiology of type 1 diabetes (T1D) is predominantly associated with T-cell-related actions. Homeostasis of majority of T-cells is critically dependent on signals mediated by CD127 (interleukin-7 receptor, IL-7R). In contrast, regulatory T-cells express very little CD127 and thereby may be delineated by CD4+CD25+CD127− phenotype. Here we aimed to analyze CD127 expression on CD4+ and CD8+ T-cells and enumerate CD4+CD25+CD127− T-cells in long-lasting T1D. T-cells were analyzed by flow cytometry and immunologic data were correlated with vascular, metabolic, and inflammatory parameters. We demonstrated significantly decreased CD127 levels on CD4+, but not CD8+, T cells in T1D pediatric patients. Interestingly, frequencies of CD4+CD25+CD127− T-cells were significantly enhanced in T1D children and correlated well with frequencies of CD34+CD144+ endothelial progenitor cells and CD4+CD25− T-cells. Levels of CD127 on both CD4+ and CD8+ T-cells in T1D patients were not correlated to each other or HbA_1C. Interestingly, however, CD127 levels on CD4+ T-cells were significantly correlated to frequencies of CD4+CD25+CD127− T-cells, whereas CD127 levels on CD8+ T-cells were significantly correlated to concentrations of VEGF and triglycerides. Our data indicate that CD127 expression is differentially modulated on CD4+ and CD8+ T-cells in the course of T1D. Moreover, we demonstrated that, in contrast to recent-onset T1D, long-lasting T1D is associated with enhancement of T-cells with regulatory phenotype.

Higher numbers of circulating endothelial progenitor cells in stroke patients with intracranial arterial stenosis

Background

Bone marrow-derived endothelial stem cells participate in vascular repairs. Numbers of circulating endothelial progenitor cells (cEPCs) are associated with atherosclerosis. Fibrinogen plays a key role in atherosclerosis. Objective was to assess if cEPC counts were associated with atherosclerotic intracranial artery stenosis (IAS).

Methods

Three hundred subjects (108 patients with stroke and IAS (IAS), 120 control patients with stroke without IAS (CP), and 72 healthy controls (HC)) were retrospectively analyzed. cEPCs were identified and counted by flow cytometry using CD34, CD133 and KDR. Plasma fibrinogen was measured by immunoturbidimetry. cEPC counts were compared between the three groups.

Results

cEPC numbers were significantly higher in IAS (0.059 ± 0.031%) than in CP (0.026 ± 0.012%) (P < 0.001) and HC (0.021 ± 0.011%) (P < 0.001), but without difference between CP and HC (P = 0.401). Multiple logistic regression analysis showed that cEPC levels (OR 3.31, 95%CI 1.26-8.87, P = 0.025; IAS vs. CP) were independent markers of IAS after adjustment for hypertension, diabetes and smoking. No significant correlation between cEPC counts and plasma fibrinogen levels was observed (P > 0.05).

Conclusion

cEPC numbers were associated with degrees of IAS. This measurement may be useful for non-invasive evaluation of atherosclerotic IAS.