Impaired endothelial function in female adolescents with type 1 diabetes measured by peripheral artery tonometry

Endothelial impairment evaluation by peripheral arterial tonometry in pediatric endocrinopathies: A narrative review

Endothelial dysfunction (ED) is characterized by an imbalance between vasodilator and vasoconstriction agents. Several pathological conditions clinically diagnosed in childhood and adolescence are characterized by ED and increased risk for early development of microangiopathic and macroangiopathic impairment, in particular type 1 diabetes mellitus (T1DM), T2DM, obesity, metabolic syndromeand pituitary dysfunction associated to various endocrinopathies. More recently insulin resistance following chemotherapy or radiotherapy for tumors, bone marrow transplantation for hematological malignancies (i.e., cancer survivors), or immunosuppressive treatment for solid organ transplantation has been observed. Assessment of ED by means of non-invasive techniques is the gold standard for early ED detection before clinical manifestation. It is aimed to recognize patients at risk and to avoid the development and progression of more serious illnesses. Reactive hyperemia-peripheral artery tonometry is a noninvasive technique to assess peripheral endothelial function by measuring modifications in digital pulse volume during reactive hyperemia, and represents a non-invasive, reproducible and operator-independent tool able to detect precocious ED. This narrative review aimed to provide an overview of the most important papers regarding ED detection by EndoPat 2000 in children and adolescents with different endocrine diseases. A comprehensive search of English language articles was performed in the MEDLINE database without using other search filters except the publication interval between 2005 and 2020.

Feasibility and Tolerance of Fingertip Peripheral Arterial Tonometry Measurements in School-Aged Children

Background: Assessment of the endothelial function of the microvasculature by peripheral arterial tonometry (PAT) has gained increasing popularity in pediatrics. Discomfort or experienced pain during fingertip PAT has only been studied in adolescents and adults. Methods: In 142 children (aged 4-11 years old), a fingertip PAT with a commercial device (EndoPAT 2000®) as well as a caliper and ultrasound examination of peripheral skinfolds were performed as part of a cross-sectional cohort study. In 110 children, Faces Pain Scale (FPS-R) data were collected after PAT and skinfold measurements by caliper and ultrasound. Results: In 111 out of the 142 PAT measurements (78.2%), a reactive hyperemia index (RHI) could be obtained. The most frequent error messages by the software was a "too noisy" and/or a "poor quality" signal. The success rate was higher in children aged older than 6 years (83.1 vs. 44.4%; p < 0.001). Median (range) FPS-R after PAT was 0 (range 0-6) but was significantly higher than the median pain experienced after caliper measurements of peripheral skinfolds (p < 0.001). No pain was experienced by 59 of the 110 children (54.1%). Conclusion: PAT testing is feasible in the great majority of school-aged children, and the procedure is well-tolerated.

Metoprolol rescues endothelial progenitor cell dysfunction in diabetes

Added risk portended by diabetes in addition to hypertension has been related to an amplification of endothelial dysfunction. β-blockers are widely used for cardiovascular diseases and improve the endothelial function compared with a placebo. However, the effect of β-blockers on the endothelial progenitor cells (EPCs) function in diabetes is still unknown. Five β-blockers (metoprolol, atenolol, propranolol, bisoprolol, and nebivolol) were tested in EPC functional screening. Metoprolol improved EPC function significantly among the five β-blockers and was chosen for the in vivo tests in STZ induced diabetic mice. Reactive hyperemia peripheral arterial tonometry (RH-PAT) measurements were performed using the Endo-PAT2000 device in diabetic patients. Metoprolol, but not other β-blockers, improved EPC function in both tube formation and migration assay. EPC function was significantly decreased in diabetic mice, and metoprolol treatment restored damaged EPC migration capabilities and circulation EPC number. Metoprolol treatment promoted wound healing and stimulated angiogenesis in diabetic mice. Furthermore, metoprolol significantly enhanced eNOS phosphorylation and decreased O₂⁻ levels in EPCs of diabetic mice. In clinical trials, the RH-PAT index was significantly higher in metoprolol-treated versus bisoprolol-treated diabetics. Metoprolol could accelerate wound healing in diabetic mice and improve endothelial function in diabetic subjects, which may be mediated in part by improving impaired EPC function.

Measurement of peripheral arterial tonometry in patients with diabetic foot ulcers during courses of hyperbaric oxygen treatment

INTRODUCTION

Treatment of diabetic foot ulcers is complex and often protracted. Hyperbaric oxygen treatment (HBOT) improves wound healing in diabetic ulcers and serves as an important adjunct to regular diabetic wound care. Endothelial dysfunction plays a central role in diabetes-related vascular complications and may be evaluated by a non-invasive technique called peripheral arterial tonometry which measures a reactive hyperaemia index (RHI). We hypothesized that endothelial function measured by peripheral arterial tonometry is impaired in diabetic foot ulcer patients and that HBOT might improve endothelial function.

METHODS

Endothelial function was prospectively assessed by peripheral arterial tonometry in 22 subjects with diabetic foot ulcers and 17 subjects without diabetes during courses of HBOT. Endothelial function was evaluated before first (baseline) and 30th treatments, and at 90-day follow-up. Serum insulin growth factor-I (IGF-I) concentrations were determined by immunoassay. Results were compared to 23 healthy subjects.

RESULTS

No baseline differences were found in endothelial function between subjects with diabetes, HBOT patients without-diabetes and healthy control subjects (RHI; 1.26, 1.61 and 1.81, respectively). No significant changes in RHI were found in patients with (P = 0.17) or without (P = 0.30) diabetes during courses of HBOT. At 90-day follow-up IGF-I was significantly reduced in the subjects with diabetes (P = 0.001) and unchanged in the group without diabetes (P = 0.99).

CONCLUSIONS

We found no significant differences in RHI between subjects with diabetic foot ulcers and patients without diabetes, nor improvement in endothelial function assessed by peripheral arterial tonometry during courses of HBOT.

Assessment of Microvascular Function in Children and Adolescents with Diabetes and Obesity

BACKGROUND

Endothelial dysfunction (ED) is a marker of vascular damage. Glycated hemoglobin (A1C) predicts vascular complications. The EndoPAT (peripheral arterial tonometry) device calculates the reactive hyperemic index (RHI), a measure of endothelial function. The greater the vasodilation, the higher the RHI. We hypothesized that children with poorly-controlled diabetes mellitus (DM) and non-diabetes mellitus (NDM) obese children have ED.

METHODS

A cross-sectional study using the EndoPAT device was performed on children with poorly-controlled DM and NDM children. ANOVA, t-test, Mann-Whitney U test, multiple linear regression and Spearman correlation were used.

RESULTS

Of 58 children that completed the study (aged 13.1 ± 3.42 years), 33 with type 1 diabetes (T1DM), 8 with type 2 diabetes (T2DM) and 17 were NDM obese children. Eighty-five percent were African-American, 60% were female and 79% entered puberty. The RHI of children with DM (1.42 ± 0.48) versus NDM obese group (1.40 ± 0.34) was not different (P = 0.86) regardless of the type of DM or body mass index. In the DM group, for every 1% increase in latest A1C, the RHI decreased by 0.097 (P = 0.01) after adjusting for age, gender, and type of DM. The RHI of DM patients with latest A1C of < 10% (1.70 ± 0.58) versus those with A1C ≥10% (1.21 ± 0.19) was statistically different (P = 0.02). In the total study population, males had significantly lower RHI (1.28 ± 0.36) when compared to females (1.51 ± 0.46), P = 0.04 but this difference disappeared when considering pubertal status and type of diabetes.

CONCLUSIONS

Our data showed that patients with poorly-controlled DM as reflected by latest A1C of ≥ 10% had worse endothelial function as reflected by lower RHI score.

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.

Effect of bariatric surgery before pregnancy on the vascular function in the offspring: protocol of a cross-sectional follow-up study

BACKGROUND

The offspring of obese pregnant women are at risk for adverse metabolic, inflammatory and cardiovascular programming. Comprehensive long-term data are lacking on the contribution of changes in maternal weight after bariatric surgery before pregnancy compared with lifestyle interventions during pregnancy on the cardiovascular programming of the offspring.

METHODS

EFFECTOR is designed as a cross-sectional cohort follow-up study targeting the children of different groups of women who were previously studied during their pregnancy. Four subgroups of children are identified, based on maternal weight characteristics during pregnancy: normal weight women, obese women without any intervention and obese women who underwent a lifestyle intervention during or bariatric surgery before pregnancy. Data collection is performed as a single study visit at home. Data on the sociodemographic situation, food habits and psychomotor development are obtained through questionnaires. During the home visit, extensive anthropometric and vascular assessment is performed. Information on body composition is provided by assessment of body weight and height, bioelectrical impedance analysis, skinfold measurements and ultrasound. Endothelial function is measured by non-invasive peripheral arterial tonometry (EndoPAT 2000). Biomarkers performed in blood and urinalysis conclude the data collection process.

TRIAL REGISTRATION NUMBER

NCT02992106 (Pre-results).

Preserved endothelial function in young adults with type 1 diabetes

Background and aim

Endothelial dysfunction is involved in the pathogenesis of atherosclerosis and is typically present in older adults with type 1 diabetes (T1D). In young adults, we aimed to assess the impact of T1D on endothelial function as detected by digital peripheral arterial tonometry (PAT) and its relationship with cardiovascular risk factors and long term glycemic control.

Materials and methods

Reactive hyperemia index (RHI) as a measure of endothelial function was assessed by PAT in 46 T1D patients and 32 healthy controls. All were participants in the "Atherosclerosis and Childhood Diabetes" study, with baseline values registered five years previously. Annual measurements of HbA1c for assessment of glycemic burden were provided by the Norwegian Childhood Diabetes Registry.

Results

The diabetes patients had a mean age of 20.8 years, a median duration of diabetes of 10.0 years and a mean HbA1c of 8.7%. RHI was not significantly decreased in the diabetes group, mean 2.00 (SD = 0.59) vs. 2.21 (SD = 0.56), p = .116. There was no gender difference or any associations with traditional risk factors. Furthermore, there was no significant association between RHI and either HbA1c or long term glycemic burden.

Conclusions

RHI as a measure of endothelial function was preserved in young adults with T1D compared with healthy controls.

In utero programming and early detection of cardiovascular disease in the offspring of mothers with obesity

The offspring of women with obesity during their pregnancy are exposed to an altered intra-uterine environment. A subsequent influence on the cardiovascular development during fetal life is assumed. In the present thematic review, we report on the current knowledge about this early development of cardiovascular disease from fetal life until adolescence. Based on animal studies, different contributing mechanisms have been hypothesized that still need confirmation in human subjects. Insulin resistance, increased levels of leptin, chronic inflammatory state, perturbation of sympathetic tone and epigenetic modifications contribute to a suboptimal nutrient environment and changed hemodynamics. The ensuing aberrant cardiomyocyte development, impaired endothelial cell relaxation and atherogenic lipid profile put these children at risk for the development of endothelial cell dysfunction. Increasing possibilities for early detection of this preliminary stage of atherosclerotic disease offer new insights into future prevention and treatment strategies. Future research should focus on further unraveling the effect of moderate intense, aerobic exercise. Since it is used to treat the condition in children and adolescents with good results, it might be a contributor to tackling endothelial cell dysfunction at its cradle when applied in early pregnancy.

Microvascular endothelial function in Japanese early adolescents

Endothelial dysfunction is the early predictive factor for the development of atherosclerosis and future cardiovascular diseases in adulthood. The prevalence of endothelial dysfunction in children and early adolescents is increasing worldwide. Peripheral arterial tonometry is a noninvasive technique for assessing peripheral microvascular function and is used as a validated marker of endothelial function. We assessed anthropometric parameters, blood pressure, arterial stiffness, and peripheral endothelial function in 157 Japanese early adolescents (75 boys and 82 girls). We measured peripheral endothelial function by using peripheral arterial tonometry to determine the reactive hyperemia index, and assessed the association of reactive hyperemia index with parameters of anthropometry and arterial stiffness. The mean reactive hyperemia index of all subjects was 1.85 ± 0.6, and there was no difference of reactive hyperemia index according to sex. Reactive hyperemia index was significantly associated with systolic and diastolic blood pressures, and had no correlation with anthropometric parameters and arterial stiffness markers. The reactive hyperemia index values among Japanese early adolescents were similar to those reported in previous studies on children and early adolescents. This noninvasive technique may be useful for the assessment of microvascular endothelial function among children and early adolescents.

Peripheral Endothelial Function After Arterial Switch Operation for D-looped Transposition of the Great Arteries

Coronary artery re-implantation during arterial switch operation in patients with D-looped transposition of the great arteries (D-TGA) can alter coronary arterial flow and increase shear stress, leading to local endothelial dysfunction, although prior studies have conflicting results. Endothelial pulse amplitude testing can predict coronary endothelial dysfunction by peripheral arterial testing. This study tested if, compared to healthy controls, patients with D-TGA after arterial switch operation had peripheral endothelial dysfunction. Patient inclusion criteria were (1) D-TGA after neonatal arterial switch operation; (2) age 9-29 years; (3) absence of known cardiovascular risk factors such as hypertension, diabetes, hypercholesterolemia, vascular disease, recurrent vasovagal syncope, and coronary artery disease; and (4) ability to comply with overnight fasting. Exclusion criteria included (1) body mass index ≥85th percentile, (2) use of medications affecting vascular tone, or (3) acute illness. We assessed endothelial function by endothelial pulse amplitude testing and compared the results to our previously published data in healthy controls (n = 57). We tested 20 D-TGA patients (16.4 ± 4.8 years old) who have undergone arterial switch operation at a median age of 5 days (0-61 days). Endothelial pulse amplitude testing indices were similar between patients with D-TGA and controls (1.78 ± 0.61 vs. 1.73 ± 0.54, p = 0.73).In our study population of children and young adults, there was no evidence of peripheral endothelial dysfunction in patients with D-TGA who have undergone arterial switch operation. Our results support the theory that coronary arterial wall thickening and abnormal vasodilation reported in these patients is a localized phenomenon and not reflective of overall atherosclerotic burden.

Long-term improvement of arterial wall characteristics in patients with diabetes mellitus type 1 using cyclic, intermittent treatment with a low-dose fluvastatin and valsartan combination

Improvement of arterial wall (AW) characteristics decreases cardiovascular risk. In a previous study, it was observed that AW characteristics in patients with diabetes mellitus type 1 are significantly improved by short-term treatment with a low-dose combination of fluvastatin and valsartan. Additionally, a unique phenomenon of prolonged effect after treatment discontinuation was suggested. The present study tested whether repeated treatm ent after a certain period results in the same beneficial effect, th ereby advancing the hypothesis that cyclic treatment can provide a long-term improvement of AW characteristics. A total of 44 patients with diabetes mellitus type 1 that participated in the previous study were recruited. Six months after the discontinuation of the initial treatment, the same treatment with a low-dose fluvastatin (10 mg daily) and valsartan (20 mg daily) combination (n=22) or placebo (n=22) was repeated. Brachial artery flow-mediated dilation (FMD), pulse wave velocity (PWV) and carotid artery β-stiffness were measured. It was found that the beneficial effect achieved with an initial 1-month treatment was completely regained following treatment repetition: FMD improved by 50.9% (P<0.01), PWV by 5.7% (P<0.001) and β-stiffness by 9.9% (P<0.001). In addition, a gradual decline of the obtained effects was observed, reaching the level of 9.6% for FM D, 6.3% for PWV and 9.5% for β-stiffness 6 months after treatm ent discontinuation. It was observed that repetition of treatment was similarly effective as the initial intervention. The benefits achieved by treatment steadily declined with time. Combining these findings, cyclic intermittent treatment with a low-dose fluvastatin and valsartan combination is proposed as a new cardiovascular preventive strategy in patients with DM1.

Puberty and type 1 diabetes

Various data on type 1 diabetes mellitus (T1DM) have showed that the incidence of T1DM peaks at puberty. However, diabetes control and complications could be adversely affected by the physiological changes of puberty. In early years of insulin therapy, severe growth retardation with pubertal delay, like in Mauriac syndrome, have been reported. Insulin and leptin are metabolic factors, circulating in the periphery, which participate in the hypothalamic control of metabolism and reproduction. Insulin may be an important regulator of leptin in humans. Increased levels of advanced glycation end products suppress activation of the gonadotropin-releasing hormone (GnRH) pulse generator, resulting in pubertal delay. Glycemic control deteriorates during puberty as the lean body mass doubles mainly over a period of 25 years, which increases insulin requirement. There is also an increase in insulin resistance over the period of puberty. In normal individuals, fasting and postprandial insulin concentrations reach a peak in both sexes in mid to late puberty. Puberty, at all stages, has the worst insulin resistance. It has been observed that an excessive GH secretion in T1DM during puberty has significant effects on ketogenesis. Adolescent T1DM tends to decompensate very rapidly and develop ketoacidosis when the late night insulin dose is omitted. Adolescence is a critical developmental phase that presents unique challenges and opportunities to individuals with diabetes, their families and their healthcare providers.

Impaired endothelial function in adolescents with overweight or obesity measured by peripheral artery tonometry

BACKGROUND

Overweight and obesity in adolescents are associated with a subsequent increased mortality due to cardiovascular disease in adulthood. The reactive hyperemia-peripheral artery tonometry (RH-PAT) is a non-invasive method for endothelial function assessment.

OBJECTIVE

The goal of this study is to investigate endothelial function as assessed with the RH-PAT in adolescents with overweight or obesity.

METHODS

In 27 adolescents with overweight or obesity (16 males, 11 females) and 25 control subjects (12 males, 13 females) (age 12-20 yr) RH-PAT score and baseline pulse amplitude were measured after an overnight fast. Confounding risk factors for endothelial dysfunction, including smoking and diabetes mellitus were excluded.

RESULTS

RH-PAT score was lower in adolescents with overweight or obesity compared to healthy controls, whereas their baseline pulse amplitude was higher (p = 0.027 and p < 0.0001, respectively). A significantly positive correlation was seen between baseline pulse amplitude and body mass index standard deviation score in the group with overweight or obese subjects.

CONCLUSIONS

Endothelial dysfunction, measured by lower RH-PAT score and higher baseline pulse amplitude, was present in overweight adolescents. Interestingly, we also report for the first time in the literature a significant difference in baseline pulse amplitude between overweight adolescents compared to their peers.

Endothelial health in childhood acute lymphoid leukemia survivors: pilot evaluation with peripheral artery tonometry

BACKGROUND

Childhood cancer survivors are a growing population at risk for poor cardiac outcomes. Acute lymphoid leukemia (ALL) survivors are among those at increased risk of cardiovascular complications. Early identification of impaired vascular health may allow for interventions to improve these outcomes. The purpose of this study was to evaluate vascular health using peripheral artery tonometry in ALL survivors and compare results with healthy siblings.

PROCEDURE

Sixteen ALL survivor, healthy sibling pairs, aged 8 to 20 years, were evaluated for vascular health and cardiovascular risk factors (body mass index, central adiposity, blood pressure, and fitness). One-tailed paired t test was used to compare the groups.

RESULTS

Survivors were similar to siblings in cardiovascular risk measures but had poorer vascular health as measured by reactive hyperemia index (survivor RHI 1.54 vs. sibling 1.77; P=0.0474).

CONCLUSION

This study reveals that even among survivors who are comparable to their healthy siblings in other traditional cardiovascular risks, there is evidence of poorer vascular health.

Alpha-Lipoic Acid and Antioxidant Diet Help to Improve Endothelial Dysfunction in Adolescents with Type 1 Diabetes: A Pilot Trial

After evaluating the prevalence of early endothelial dysfunction, as measured by means of reactive hyperemia in adolescents with type 1 diabetes, we started a 6-month, double-blind, randomized trial to test the efficacy of an antioxidant diet (± alpha-lipoic acid supplementation) to improve endothelial dysfunction. Seventy-one children and adolescents, ages 17 ± 3.9 yrs, with type 1 diabetes since 9.5 ± 5.3 yrs, using intensified insulin therapy, were randomized into 3 arms: (a) antioxidant diet 10.000 ORAC + alpha-lipoic acid; (b) antioxidant diet 10.000 ORAC + placebo; (c) controls. BMI, blood pressure, fasting lipid profile, HbA1c, insulin requirement, dietary habits, and body composition were determined in each patient. An antioxidant diet significantly improved endothelial dysfunction when supplemented with alpha-lipoic acid, unlike diet with placebo or controls. A significant reduction in bolus insulin was also observed. We speculate that alpha-lipoic acid might have an antioxidant effect in pediatric diabetes patients by reducing insulin.

Evaluation of endothelial function by peripheral arterial tonometry and relation with the nitric oxide pathway

Endothelial dysfunction is an important component in the development of cardiovascular diseases. Endothelial function may be evaluated by peripheral arterial tonometry (PAT) which measures the vasodilator function in the microvasculature of the fingertip during reactive hyperaemia. The reactive hyperaemia index (RHI) is decreased in the presence of cardiovascular risk factors and thus far several studies have shown that PAT-RHI may provide reliable prediction of outcome. The technique is operator independent and easy to perform. Abnormalities measured by PAT follow the same trend as those measured by flow-mediated dilation in the brachial artery, but the two methods are not interchangeable. We have reviewed the recent literature in an effort to evaluate peripheral arterial tonometry as a method to assess the function of the endothelium and additionally suggest directions for future research. Special attention will be directed to the nitric oxide dependency of the reactive hyperaemia index obtained by peripheral arterial tonometry.

Puberty as an accelerator for diabetes complications

Much is written about how difficult it is to deal with diabetes during adolescence, and rightly so. Less is understood as to how puberty may be an accelerator of vascular complications. With the increase in childhood diabetes, complication risks need to be revisited in relation to puberty and the secular increase in adiposity. Recent data suggest greater risk for severe vascular complications in those with diabetes during puberty, compared with young people who develop diabetes after puberty. It is also widely recognized that higher hemoglobin A1c (HbA1c) results are often seen during the pubertal period. This article will review complication outcomes in relation to puberty and examine mechanisms by which puberty may modify risk above glycemic exposure, and possible gender disparities in the risk of complications in the adolescent period.