Prediabetic obese adolescents have a more atherogenic lipoprotein profile compared with normoglycemic obese peers

A Comparative Study on Levels of hs-CRP and Lipid Profile in Prediabetic and Normal Population

This study aimed to compare high-sensitivity C-reactive protein (hs-CRP) and lipid profile levels between prediabetic and normal populations and explore correlations between hs-CRP and lipid profile in prediabetic individuals. The study was conducted among Group A comprising 75 prediabetic individuals, and Group B, which included 75 non-diabetic controls from the general population. Results showed that the mean hs-CRP level in Group A (1.717) significantly exceeded that of Group B (0.917) (p = 0.001). Pearson correlation analysis revealed significant positive linear relationships between hs-CRP and lipid profile parameters, indicating that as total cholesterol, triglycerides (TGs), high-density lipoprotein (HDL), and very low-density lipoprotein (VLDL) increased, hs-CRP also increased. A significant negative linear relationship was observed between hs-CRP and HDL. Moreover, a positive linear relationship existed between hs-CRP and glycemic parameters (fasting blood sugar (FBS), postprandial blood sugar (PPBS), and Glycated haemoglobin (HbA1c)). It is concluded that elevated hs-CRP, an inflammatory marker, correlated with dysregulated lipid profiles, and glycemic parameters, indicating its potential role in assessing inflammation in prediabetic individuals and its association with dyslipidemia and glucose metabolism.

Small dense low density lipoprotein predominance in patients with type 2 diabetes mellitus using Mendelian randomization

BACKGROUND

Patients with T2DM often suffer from CVD-related complications, significantly impacting morbidity and mortality rates. The upsurge in CVD prevalence among them is partly linked to sd LDL particles. Understanding the mechanisms behind elevated sd LDL levels is critical for preventing and managing cardiovascular complications in diabetes.

METHODS

MR was employed to identify instrumental variables and establish causality, exploring underlying mechanisms.

RESULTS

Notably, T2DM itself, insulin resistance, and fasting glucose seemingly do not directly impact sd LDL levels. Instead, the presence of T2DM or insulin resistance, leading to reduced HDL cholesterol or elevated TG levels, directly contributes to subsequent sd LDL increases, indicating a comprehensive mediating effect. While LDL cholesterol levels correlate positively with sd LDL, they appear unaffected by T2DM or insulin resistance. Importantly, hypertension induced by T2DM or insulin resistance exhibits a positive effect on sd LDL reversal. Unlike T2DM or insulin resistance, blood glucose levels show no significant impact on all processes.

CONCLUSIONS

It is hoped that these insights might influence the treatment of patients with diabetes and the management of blood parameters in clinical practice. Examining the effect of T2DM or insulin resistance on sd LDL within HDL cholesterol and triglycerides pathways might provide valuable insights for targeted cardiovascular treatments. Additionally, the study's exploration of the potential positive effects of elevated blood pressure on sd LDL reversal may introduce novel considerations for blood pressure management in patients with diabetes.

The Impact of Aerobic Exercise on HDL Quantity and Quality: A Narrative Review

High-density lipoproteins comprise roughly 25-30% of the circulating proteins involved in the transport of lipids in circulation. These particles differ in size and lipid composition. Recent evidence suggests that the quality of HDL particles (which depends on shape, size and the composition of proteins and lipids determining HDL functionality) may be more important than their quantity. The functionality of HDL is mirrored by its cholesterol efflux activity, as well as its antioxidant (including the protection of LDL against oxidation), anti-inflammatory and antithrombotic properties. The results of many studies and meta-analyses imply the beneficial impact of aerobic exercise on HDL-C levels. Physical activity was found to be usually associated with an increase in HDL cholesterol and a decrease in LDL cholesterol and triglycerides. Exercise, apart from inducing quantitative alterations in serum lipids, exerts a beneficial impact on HDL particle maturation, composition and functionality. The Physical Activity Guidelines Advisory Committee Report underlined the importance of establishing a program recommending exercises that enable attainment of maximal advantage at the lowest level of risk. The aim of this manuscript is to review the impact of different types of aerobic exercise (various intensities and durations) on the level and quality of HDL.

The Relationship Between Lipoproteins and Insulin Sensitivity in Youth With Obesity and Abnormal Glucose Tolerance

CONTEXT

Youth with obesity and abnormal glucose tolerance have an increased risk for atherosclerosis but the relative contributions of insulin resistance and hyperglycemia to dyslipidemia and the development of subclinical atherosclerosis are unknown.

OBJECTIVE

This work aims to determine the association between insulin resistance, dyslipidemia, and carotid intimal thickness (cIMT) in adolescents with normal and abnormal glucose tolerance.

METHODS

An observational cohort study in 155 youth: 44 obese insulin sensitive (OIS; fasting insulin ≤ 20 µM/mL, body mass index [BMI] ≥ 95th percentile), 35 obese insulin resistant (OIR; fasting insulin > 20 µM/mL, BMI ≥ 95th percentile), 34 obese abnormal glucose tolerant (AGT; BMI ≥ 95th percentile), and 42 Lean (BMI 5th-85th percentile). Lipids, lipoprotein particle size and concentration (-P), insulin sensitivity (SI an intravenous glucose test), and CMIT were compared using linear models adjusted for age, race/ethnicity, biological sex, and Tanner stage. Lipid/lipoprotein profile and CMIT were reevaluated in a subset after 2 years.

RESULTS

Compared to OIS and Lean, OIR and AGT had elevated triglycerides and low high-density lipoprotein cholesterol (HDL-C) but similar total cholesterol and low-density lipoprotein cholesterol (LDL-C). Among OIS, OIR, AGT, lower SI was associated with atherogenic lipids (higher triglycerides, LDL-C, non-HDL-C, and lower HDL-C) and lipoproteins (higher total LDL-P and small HDL-P, and lower large HDL-P). There was a steeper decline in the association of SI with HDL-C and large HDL-P in AGT compared with OIR and OIS. cIMT was comparable across groups and inversely correlated with SI, with no change after 2 years.

CONCLUSION

Among youth with obesity, insulin resistance was associated with an atherogenic lipoprotein/lipid profile and cIMT, regardless of glucose tolerance status. Insulin resistance in AGT youth was associated with a shift to smaller HDL-P compared to normoglycemic youth with obesity. Alterations in HDL-P metabolism may be early adverse manifestations of hyperglycemia in youth with obesity.

Changes in the profile of circulating HDL subfractions in severe obese adolescents following a weight reduction program

BACKGROUND AND AIMS

Epidemiological studies show that obese adolescents are candidates to suffer cardiovascular pathologies in adulthood. In order to detect subfractions with a diagnostic value for future cardiovascular disorders, we analyzed the complete lipoprotein profile of severely obese adolescents.

METHODS AND RESULTS

Twenty-eight obese adolescents free from comorbidities were admitted into a weight reduction program. Anthropometric parameters were monitored. The circulating lipoproteins and glycemia were measured at the beginning and at the end of the study by conventional blood analysis as well as by using lipoprotein electrophoresis. Twenty-one puberty-matched normal-weight adolescents were recruited as controls. After 4 months, participants improved anthropometric parameters. Blood analysis indicated that circulating lipoproteins were in the healthy range during intervention. Nevertheless, results obtained from lipoprotein electrophoresis showed a significant increase in the large high-density lipoprotein subfraction in the obese population at the end of intervention, but significantly lower than normal-weight counterparts. In addition, intermediate- and low-density lipoprotein subfractions were in the healthy range in controls and in obese adolescents during intervention.

CONCLUSIONS

Altogether, it seems that the obese adolescents with no comorbidities do not develop a clear dyslipidemia. However, low values of large high-density lipoprotein subfractions could be considered as candidate predictors to develop cardiovascular disease in the future. For this reason, diet and exercise are key tools to fight against this pathology.

REGISTRATION NUMBER FOR CLINICAL TRIALS

ISRCTN99414527.

Nuclear Magnetic Resonance Derived Biomarkers for Evaluating Cardiometabolic Risk in Youth and Young Adults Across the Spectrum of Glucose Tolerance

Youth with obesity have an increased risk for cardiometabolic disease, but identifying those at highest risk remains a challenge. Four biomarkers that might serve this purpose are "by products" of clinical NMR LipoProfile^® lipid testing: LPIR (Lipoprotein Insulin Resistance Index), GlycA (inflammation marker), BCAA (total branched-chain amino acids), and glycine. All are strongly related to insulin resistance and type 2 diabetes (T2DM) in adults (glycine inversely) and are independent of biological and methodological variations in insulin assays. However, their clinical utility in youth is unclear. We compared fasting levels of these biomarkers in 186 youth (42 lean normal glucose tolerant (NGT), 88 obese NGT, 23 with prediabetes (PreDM), and 33 with T2DM. All four biomarkers were associated with obesity and glycemia in youth. LPIR and GlycA were highest in youth with PreDM and T2DM, whereas glycine was lowest in youth with T2DM. While all four were correlated with HOMA-IR (Homeostatic Model Assessment for Insulin Resistance), LPIR had the strongest correlation (LPIR: r = 0.6; GlycA: r = 0.4, glycine: r = -0.4, BCAA: r = 0.2, all P < 0.01). All four markers correlated with HbA1c (LPIR, GlycA, BCAA: r ≥ 0.3 and glycine: r = -0.3, all P < 0.001). In multi-variable regression models, LPIR, GlycA, and glycine were independently associated with HOMA-IR (Adjusted R² = 0.473, P < 0.001) and LPIR, glycine, and BCAA were independently associated with HbA1c (Adjusted R² = 0.33, P < 0.001). An LPIR index of >44 was associated with elevated blood pressure, BMI, and dyslipidemia. Plasma NMR-derived markers were related to adverse markers of cardiometabolic risk in youth. LPIR, either alone or in combination with GlycA, should be explored as a non-insulin dependent predictive tool for development of insulin resistance and diabetes in youth.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov, identifier NCT:02960659.

Dyslipidemia in Pediatric Type 2 Diabetes Mellitus

PURPOSE OF REVIEW

Cardiovascular (CV) disease is a major cause of mortality in type 2 diabetes mellitus (T2D). Dyslipidemia is prevalent in children with T2D and is a known risk factor for CVD. In this review, we critically examine the epidemiology, pathophysiology, and recommendations for dyslipidemia management in pediatric T2D.

RECENT FINDINGS

Dyslipidemia is multifactorial and related to poor glycemic control, insulin resistance, inflammation, and genetic susceptibility. Current guidelines recommend lipid screening after achieving glycemic control and annually thereafter. The desired lipid goals are low-density lipoprotein cholesterol (LDL-C) < 100 mg/dL, high-density lipoprotein cholesterol (HDL-C) > 35 mg/dL, and triglycerides (TG) < 150 mg/dL. If LDL-C remains > 130 mg/dL after 6 months, statins are recommended with a treatment goal of < 100 mg/dL. If fasting TG are > 400 mg/dL or non-fasting TG are > 1000 mg/dL, fibrates are recommended. Although abnormal levels of atherogenic TG-rich lipoproteins, apolipoprotein B, and non-HDL-C are commonly present in pediatric T2D, their measurement is not currently considered in risk assessment or management.

Postprandial dyslipidemia in insulin resistant states in adolescent populations

Obesity and the metabolic syndrome are becoming increasingly prevalent not only in adults, but also in adolescents. The metabolic syndrome, a complex cluster of metabolic abnormalities, increases one's risk of developing type 2 diabetes and cardiovascular disease (CVD). Dyslipidemia, a key component of the metabolic syndrome, is highly associated with insulin resistance and contributes to increased CVD risk. Dyslipidemia has traditionally been assessed using a fasting lipid profile [i.e. fasting triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)]. However, the postprandial state predominates over the course of a day and non-fasting triglycerides independently predict CVD risk. In insulin resistant states, the intestine overproduces triglyceride-rich lipoprotein (TRL) particles, termed chylomicrons (CMs), following ingestion of a fat-containing meal, as well as in the fasting state. Along with elevated hepatic TRLs (i.e. very-low density lipoproteins), CMs contribute to remnant lipoprotein accumulation, small dense LDL particles, and reduced HDL-C, which collectively increase CVD risk. Given the early genesis of atherosclerosis and physiological metabolic changes during adolescence, studying postprandial dyslipidemia in the adolescent population is an important area of study. Postprandial dyslipidemia in the pediatric population poses a significant public health concern, warranting a better understanding of its pathogenesis and association with insulin resistance and CVD. This review discusses the metabolic syndrome, focusing on the link between insulin resistance, postprandial dyslipidemia, and CVD risk. Furthermore, the clinical significance and functional assessment of postprandial dyslipidemia, specifically in the adolescent population, is discussed in more detail.

Obesity is associated with an altered HDL subspecies profile among adolescents with metabolic disease

We aimed to determine the risk factors associated with the depletion of large HDL particles and enrichment of small HDL particles observed in adolescents with T2D. Four groups of adolescents were recruited: 1) lean insulin-sensitive (L-IS), normal BMI and no insulin resistance; 2) lean insulin-resistant (L-IR), normal BMI but insulin resistance (fasting insulin levels ≥ 25 mU/ml and homeostatic model assessment of insulin resistance ≥ 6); 3) obese insulin-sensitive (O-IS), BMI ≥ 95th percentile and no insulin resistance; and 4) obese insulin-resistant (O-IR), BMI ≥ 95th percentile and insulin resistance. Plasma was separated by using gel-filtration chromatography to assess the HDL subspecies profile and compared with that of obese adolescents with T2D (O-T2D). Large HDL subspecies were significantly lower across groups from L-IS > L-IR > O-IS > O-IR > O-T2D (P < 0.0001); small HDL particles were higher from L-IS to O-T2D (P < 0.0001); and medium-sized particles did not differ across groups. The contributions of obesity, insulin resistance, and diabetes to HDL subspecies profile were between 23% and 28%, 1% and 10%, and 4% and 9%, respectively. Obesity is the major risk factor associated with the altered HDL subspecies profile previously reported in adolescents with T2D, with smaller contributions from insulin resistance and diabetes.

Sex Differences in Cardiometabolic Risk Factors among Hispanic/Latino Youth

OBJECTIVE

To determine the prevalence of obesity and cardiometabolic risk in US Hispanic/Latino youth and examine whether there are disparities by sex in cardiometabolic risk factors.

STUDY DESIGN

Study of Latino Youth is a population-based cross-sectional study of 1466 Hispanic/Latino youth (8-16 years old) who were recruited from 4 urban US communities (Bronx, NY, Chicago, IL, Miami, FL, and San Diego, CA) in 2012-2014. The majority of children were US-born (78%) and from low-income and immigrant families. Cardiometabolic risk factors were defined by the use of national age- and sex-specific guidelines.

RESULTS

The prevalence of obesity was 26.5%. The prevalence of class II-III obesity, diabetes, and dyslipidemia was high (9.7%, 16.5%, and 23.3%, respectively). The prevalence of cardiometabolic risk factors increased with severity of obesity in both boys and girls. Boys had a greater prevalence of diabetes and of elevated blood pressure than girls (20.9% vs 11.8% and 8.5% vs 3.3%). In multivariable analyses, younger boys were more likely to have obesity class II-III than girls (OR 3.59; 95% CI 1.44-8.97). Boys were more likely to have prediabetes than girls (OR 2.02; 95% CI 1.35-3.02), and the association was stronger at older ages.

CONCLUSIONS

The prevalence of cardiometabolic risk factors was high in this sample of Hispanic youth. Boys had a more adverse cardiometabolic profile compared with girls that may put them at higher risk of diabetes and cardiovascular disease later in life. Reasons for this disparity and the long-term clinical implications remain to be elucidated.

Superiority of lipoprotein particle number to detect associations with arterial thickness and stiffness in obese youth with and without prediabetes

BACKGROUND

The nuclear magnetic resonance (NMR) lipoprotein profile provides additional cardiovascular risk information beyond traditional lipids in high-risk adults. Similar studies have not been conducted in youth.

OBJECTIVE

To evaluate the relationship between the NMR profile and preclinical vascular measures in youth.

METHODS

We studied 96 obese youth with prediabetes (mean age = 18.1 ± 3.6 years, 63% female, 78% African American) and 118 obese normoglycemic controls (mean age = 18.0 ± 3.1 years, 75% female, 62% African American) cross sectionally. Traditional lipids (triglycerides, total, high-density lipoprotein [HDL], and low-density lipoprotein [LDL] cholesterol), NMR particle size (particle concentration [P] and size) and vascular thickness (carotid IMT) and stiffness (pulse wave velocity [PWV]) were measured. Independent associations between lipoproteins with carotid IMT and PWV after adjustment for group, age, race, sex, BMI z score, blood pressure, HOMA-IR, and A1c were studied.

RESULTS

NMR analysis revealed youth with prediabetes exhibited a more atherogenic profile with higher levels of small LDL-P and HDL-P and lower levels of intermediate and large HDL-P (P < .03). In addition, lower intermediate HDL-P was associated with a higher carotid IMT, whereas higher small HDL-P was associated with a higher PWV (P < .01). Traditional lipids were not significantly different between groups and were not associated with either vascular outcome.

CONCLUSIONS

NMR lipoprotein subclasses have improved sensitivity compared to traditional lipids to detect lipoprotein abnormalities in normoglycemic and prediabetic obese youth and are independently associated with preclinical vascular thickness and stiffness. NMR lipids may enhance cardiovascular risk assessment in youth.

Pre-diabetes in overweight youth and early atherogenic risk

PURPOSE

To compare atherogenic lipoprotein particles and vascular smooth muscle biomarkers in overweight youth with pre-diabetes (PD) vs. normal glucose tolerance (NGT).

METHODS

144 adolescents (60 black, 84 white; 102 female; PD=45, NGT=99) aged 10-19 years underwent a fasting blood draw and 2-h OGTT. Lipoprotein particle size and subclass concentration and vascular smooth muscle biomarkers (ICAM-1, VCAM-1 and E-selectin) were compared between youth with PD and NGT.

RESULTS

Compared with NGT, PD adolescents had smaller LDL (mean±SE: 20.5±0.1 vs. 21.0±0.1 nm; P=0.002) and HDL (8.62±0.05 vs. 8.85±0.04 nm; P=0.013) size and elevated medium small (159.2±10.3 vs. 123.8±6.4 nmol/L; P=0.037) and very small (626.3±45.4 vs. 458.5±26.4 nmol/L; P=0.032) LDL particle concentrations, after adjustment for race and BMI. Further adjusting for fasting insulin or visceral adiposity obviated these differences between the groups except for LDL size. ICAM-1 and E-selectin did not differ in youth with PD but correlated with LDL and HDL size, and small LDL particle concentrations.

CONCLUSIONS

Overweight adolescents with PD have an atherogenic lipoprotein profile of small LDL and HDL size and increased concentrations of small LDL, moderated by insulin resistance and visceral adiposity, but independently driven by dysglycemia for LDL size. Associations between smooth muscle biomarkers and lipoproteins could be an early signal heralding the atherogenic process. It remains to be determined if correction of dysglycemia and associated lipoprotein abnormalities in obese youth could prove effective in halting this process.

Effect of relative weight group change on nuclear magnetic resonance spectroscopy derived lipoprotein particle size and concentrations among adolescents

OBJECTIVE

To examine whether longitudinal changes in relative weight category (as indicated by change in body mass index [BMI] classification group) were associated with changes in nuclear magnetic resonance (NMR)-derived lipoprotein particles among US youth.

STUDY DESIGN

Secondary analysis of data from a clustered randomized controlled trial. BMI and fasting blood samples were obtained from 2069 participants at the start of the 6th grade and end of the 8th grade. BMI was categorized as normal weight, overweight, or obese at both time points. Lipoprotein particle profiles were measured with NMR spectroscopy at both time points. Regression models were used to examine changes in relative weight group and change in lipoprotein variables.

RESULTS

A total of 38% of participants changed relative weight category (BMI group) during the 2.5-year study period. Low-density lipoprotein (LDL) cholesterol and non-high-density lipoprotein (HDL) cholesterol decreased almost universally, but more with improved BMI category. There were adverse effects on LDL size and total LDL particles, HDL size, and cholesterol for participants who remained obese or whose relative weight group worsened. Changes in relative category had no impact on HDL particles.

CONCLUSION

Improvement in relative weight group from 6th to 8th grade was associated with favorable changes in non-HDL cholesterol, very low-density lipoprotein size, LDL size, HDL size, and LDL particles but had no effect on HDL particles. Findings indicate that an improvement in relative weight group between 6th and 8th grade had an effect on NMR-derived particles sizes and concentrations among a large group of adolescents, which overrepresented low-income minorities.

Oxidized low density lipoprotein and total antioxidant capacity in type-2 diabetic and impaired glucose tolerance Saudi men

BACKGROUND

Oxidative modification of low density lipoproteins (LDL) convert these native particles into pathogenic, immunogenic and atherogenic particles. Factors enhance LDL oxidation are poorly understood, especially in conditions of hyperglycemia. The present study was conducted to investigate which metabolic conditions are associated with the promotion of LDL oxidation in different glycemic situations.

METHODS

Adult male participants (274) were selected from patients admitted to the outpatient department of Diabetes Center in Al-Noor Specialized Hospital in Makkah and other citizens and residents in the city. The studied group was classified into three sub-groups: Group-I: control group of non-diabetic normal subjects, Group-II: subjects with impaired glucose tolerance (IGT) and Group-III: cases of type-2 diabetes mellitus (DM). Measurement of fasting blood glucose, 2 hour post-prandial blood glucose, glycosylated hemoglobin (HbA1c), triglycerides, serum cholesterol, HDL-cholesterol, LDL-cholesterol, ox-LDL, Total Antoxidant capacity (TAC) and Malondialdehyde (MDA) were performed. The obtained results were statistically analyzed.

RESULTS

Oxidation of native LDL increase nearly two folds in Type-2 DM group compared to controls. There is also significant increase in Ox-LDL of IGT group compared to controls. The correlation between Ox-LDL concentration and HbA1c in the whole population of the study confirms the increased Ox-LDL in subjects with hyperglycemia. A negative correlation exists between the concentration of Ox-LDL and total antioxidant capacity (TAC) in each studied group and in the whole population of the study as well. A positive correlation also exists between Ox-LDL concentrations and LDL values, more clear in controls and Type-2 DM, while this correlation was not significant in IGT group. The ratio of LDL oxidation as expressed by ox-LDL/LDL was increased in IGT group compared to control. More significant increase was observed in type-2 DM group.

CONCLUSION

We concluded that the concentration of Ox-LDL increased in subjects with type-2 DM and IGT compared to controls. Moreover, oxidation of native LDL was associated with low levels of TAC and positively correlated with LDL levels, total cholesterol, HbA1c, body mass index (BMI) and increased age.