Lipoprotein Profile Research Articles

Abstract 4121104: Fish Oil-Derived N-3 Very-Long-Chain Polyunsaturated Fatty Acids Improve Retinal Function in Aged Mice

Introduction: Epidemiological studies and clinical trials have revealed cardiometabolic benefits associated with dietary fish oil-derived omega-3 polyunsaturated fatty acids, particularly EPA and DHA. Omega-3 very-long-chain polyunsaturated fatty acids (VLCPUFA), synthesized in vivo by very-long-chain fatty acid elongase (ELOVL), e.g. ELOVL2 and 4, have recently garnered interest for their role in eye and cardiometabolic diseases. In our previous study, aging mice fed a VLCPUFA-rich diet for 8 weeks exhibited lowered plasma lipid levels, and repeated gavage of VLCPUFA in young mice resulted in improved retinal function. However, it is largely not known if VLCPUFA intake for a short term in aged mice would also improve retinal function and have beneficial effects in cardiometabolic risk factors. Hypothesis: We hypothesized that VLCPUFA may delay or rescue age-related vision loss by supplementing the products of ELOVL2, which decrease in quantity with age. We also hypothesize that short-term VLCPUFA intake may also confer favorable cardiometabolic benefits. Aims: We aimed to evaluate the effects of exogenous VLCPUFA on visual function and lipoprotein profiles in aged mice. Methods: Sixteen-month-old mice received a daily oral gavage of C24-28-rich VLCPUFA-oil (80 mg/kg BW) or an Intralipid vehicle for 15 consecutive days (n=8). The electroretinogram (ERG) instrument used was a UTAS E-3000 with gold corneal and stainless-steel scalp electrodes. Fast Protein Liquid Chromatography was performed using pooled plasma. Results: Consumption of VLCPUFA for 15 days increased scotopic a- (p < 0.05 at −5, 0, 5, 10, and 15 dB) and b-wave (p < 0.05 at 0 and 5 dB, p = 0.08 at 10 dB) amplitudes on ERG in both male and female mice compared with control. Although photopic ERG results did not exhibit statistically significant differences, likely due to low sample size, the overall results were consistent with those in our previous studies in young mice. We report no statistically significant difference in the composition of pro-atherogenic VLDL and LDL fractions due to VLCPUFA gavage. Increasing the duration and samples size in future gavage studies may be critical to determine the effects of VLCPUFA on eye and cardiovascular risk factors. Conclusions: This study revealed that a short-term oral administration of VLCPUFA was effective in improving ERG response overall, but not lipoprotein profiles.

Serum Lipoprotein Profiling by NMR Spectroscopy Reveals Alterations in HDL-1 and HDL-2 Apo-A2 Subfractions in Alzheimer's Disease.

Identifying biomarkers for Alzheimer's disease (AD) is crucial, due to its complex pathology, which involves dysfunction in lipid transport, contributing to neuroinflammation, synaptic loss, and impaired amyloid-β clearance. Nuclear magnetic resonance (NMR) is able to quantify and stratify lipoproteins. The study investigated lipoproteins in blood from AD patients, aiming to evaluate their diagnostic potential. Serum and plasma were collected from AD patients (n = 25) and healthy individuals (n = 25). We conducted a comprehensive lipoprotein profiling on serum samples using NMR spectroscopy, analysing 112 lipoprotein subfractions. In plasma, we measured unspecific markers of neuronal damage and AD hallmark proteins using single molecule array technology. Additionally, clinical data and cerebrospinal fluid biomarker levels were also collected to enrich our data. Our findings, after adjusting for age and sex differences, highlight significant alterations in two specific lipoproteins; high-density lipoprotein (HDL)-1 Apo-A2 (H1A2) and HDL-2 Apo-A2 (H2A2), both with area under the curve (AUC) values of 0.67, 95% confidence interval (CI) = 0.52-0.82). These results indicate that these lipoprotein subfractions may have potential as indicators of AD-related metabolic changes.

Triple-hormone receptor agonist retatrutide significantly improves lipoprotein and apolipoprotein profiles in participants with obesity or overweight

Abstract Background In a phase 2 study in participants who have obesity or overweight but not type 2 diabetes (T2D) (n=338), retatrutide (RETA), an agonist of GIP, GLP-1 and glucagon receptors, reduced body weight, glycated hemoglobin, triglycerides (TG), LDL-C and VLDL-C. Purpose To better understand the effects of RETA on the serum lipid profile we analyzed changes in apolipoprotein levels and distribution and size of lipoprotein particles. Methods Adult participants with obesity (BMI ≥30 kg/m2), or overweight (BMI ≥ 27 kg/m2 and < 30 kg/m2) with a weight-related comorbidity, and without T2D were randomized to receive RETA 1, 4, 8, 12 mg or placebo for 48 weeks. Lipids panel (including calculated non-HDL-C), apolipoproteins (apo) and NMR lipoprotein profiles were measured at baseline, 24 and 48 weeks in fasting plasma samples. Data were analyzed using a mixed model for repeated measures after log transformation. Results RETA dose-dependently reduced non-HDL-C up to 22.2% and 26.9% and apoB up to 19.6% and 24.2% at 24 and 48 weeks, respectively (Figure). At 48 weeks, RETA reduced TG and apoC-III levels up to 40.6% and 38.0%, respectively. RETA greatly reduced the total number of TG-rich lipoprotein particles (TRLP) and all subfractions of TRLP (large, medium and small) at 48 weeks (Table). Since the reduction in large and medium TRLP was greater than the reduction in small TRLP, the average size of TRLP was smaller following treatment with RETA. RETA reduced the number of total and highly atherogenic small LDL particles (LDLP), while total and small HDL particles (HDLP) were only slightly reduced. The average size of HDLP increased following treatment with RETA. At 48 weeks, the NMR-derived lipoprotein insulin resistance score was dose-dependently decreased by 27.4%, 31.7% and 32.5% with 4 mg, 8 mg and 12 mg, respectively, following RETA treatment. Conclusions RETA treatment for 48 weeks dose-dependently reduced levels of non-HDL-C and apoB and the number of total and small LDL particles, suggesting an improvement in atherogenic lipoprotein profile and cardiovascular risk in subjects who have obesity or overweight but not T2D.

A novel classification of dyslipidaemia through the analysis of five million lipid profiles: an unsupervised machine learning approach

Abstract Background Dyslipidemia encompasses a wide range of lipoprotein disorders categorised through two classifications (Fredrickson-Levy [FL] or Sniderman).(1,2) However, both classifications are criticised for relying on incomplete knowledge of lipoprotein metabolism, especially with the emergence of novel treatment options and variations in individual treatment responses.(3) Clustering, an unsupervised machine learning (ML) algorithm that can process a wide range of variables, has the potential to unmask patient groups with distinct molecular profiles and unique therapeutic targets that can inform more effective prevention strategies for cardiovascular disease (CVD).(4) Aim We aimed to use unsupervised ML algorithms to discover intrinsic dyslipidaemia categories from lipoprotein measurements, recognise the necessary components of lipid panels for classification, and analyse the similarities between the newly formed clusters, FL and Sniderman classifications. Methods Lipid profiles of 5,080,248 patients were obtained from the ‘Very Large Database of Lipids’ database. This yielded up to 78 blood components per patient, including at least 31 lipoprotein variables. The analysis involved unsupervised K-means clustering with optimised values for K and the subset of variables, determined in an unsupervised manner using a suitable measure of complexity. We then interpreted our clusters using probabilistic decision trees to provide compact and interpretable representations. Finally, we compared the clusters with Sniderman and FL categories. Results In a completely unsupervised fashion, we identified 14 clusters that could be matched to Sniderman categories. The confusion matrix showed total agreement of 76% (see Figure 1, left panel), relative Cohen’s kappa of 0.78 (the relative version captures accuracy on categories containing smaller numbers of patient profiles) and an accuracy of 96% on the small Type III class. Similar results were observed when matching to FL types. We accurately represented our clusters using probabilistic decision trees of small depth (see Figure 2). We discovered that the data had low intrinsic dimension and a manifold-like structure in which the different clusters could be illustrated (see Figure 1, right panel). Specifically, only 3 variables were needed to obtain our classification: apolipoprotein b, total cholesterol and triglycerides. Conclusion We showed that completely unsupervised ML techniques can uncover dyslipidaemia categories in lipoprotein profiles from a large patient population. The categories largely align with existing classifications based on prior knowledge of lipoprotein metabolism. Furthermore, few lipoprotein variables were required for categorisation (low-dimension data), which could aid in determining which lipoproteins should be measured in a clinical setting. Further analysis of the differences between ML clusters and traditional classifications is needed, which may enhance CVD risk management.

Lipid changes across menopause status point to increased cardiovascular risk

Abstract Background While women develop cardiovascular disease (CVD) approximately ten years later than men, risk of CVD in women rises precipitously following menopause. The mechanisms underlying this acceleration in CVD risk are not well elucidated, but adverse changes in lipid measures are known to occur during the perimenopause period. Previous investigations have been largely restricted to traditional lipid measures and have not examined changes in lipoprotein particles including lipid subfractions and particle number. Purpose We sought to examine longitudinal changes in lipoprotein particles that occur during the menopause transition. Methods A total of 1305 participants in the Dallas Heart Study with known menopause status underwent measurement of LDL-P, HDL-P, sd-LDL, and ld-HDL by NMR LipoProfile LP4 algorithm (LabCorp, Raleigh Durham, NC, U.S.A.) at 2 examinations (between 7-8 years between DHS studies). We compared longitudinal changes in lipoprotein measures between pre-, peri-, post-menopausal women and men using multivariable adjusted linear regression models. For our analysis peri- is the group that was pre-menopause at DHS I and post-menopause at DHS 2, not to mean the period before menopause. Results There 1346 men (referent group) included in the study with a mean age of 43 ± 9.4 years. There was a total of 1246 women with a mean age of 42 ± 5.6 for peri-group, 54 ± 6.2 for post-group, and 34 ± 3.08 for the pre-group. Of the women 440 (35.3%) were pre-menopausal, 298 (23.9%) were peri-menopausal, and 508 (40.8%) were post-menopausal. Over a median follow-up time of 7 years. All three groups had an increase in LDL-P but the greatest percent change is between peri and post, 18.30 (SE 3.05, P<0.001). When compared to men the post-group has the greatest percent change of HDL-P with a negative change of 4.77 (SE 0.948 P<0.0001). Small-dense LDL had the highest percent change in the peri- group when compared to men with a change of 578.62 (SE 288.45, P<0.045). Large-dense HDL had greatest percent change in the post- group when compared to men with negative change of 37.84 (SE 12.83, P<0.0032). Conclusions We found that menopause is associated with adverse changes in lipoprotein profiles, with the most pronounced changes in LDL-particles and subfractions observed for peri-menopausal women. By contrast, post-menopausal women demonstrated the greatest reductions in HDL-particles and subfractions. Taken together, these changes suggest that menopause is associated with a transition to a more atherogenic lipoprotein profile. Further research is needed to investigate whether these adverse changes in lipoproteins translate to greater CV risk.

Cardiometabolic risk assessment in transgender individuals - differential impact of sex hormones and sex chromosomes.

While transgender individuals represent a significant group seeking medical care, the differential effect of sex on cardiometabolic risk metrics is incompletely understood. Therefore, the current study aimed to characterize the impact of sex hormones and chromosomes on a contemporary panel of cardiometabolic risk biomarkers and functional cardiovascular measurements. 17 transmen and 17 transwomen were studied at baseline (T0), 4 weeks (hormonal castration, T1), and 11 months following gender-affirming hormone treatment (T12). We analyzed carotid intima-media thickness (cIMT) and arterial stiffness, lipoproteins and other metabolites comprehensively by nuclear magnetic resonance spectroscopy and HDL-mediated cholesterol efflux capacity (CEC) from macrophages. T0 to T12 comparisons informed the impact of sex hormones, comparisons of genetic XX and XY individuals at T1 the impact of sex chromosomes. Vascular function was comparable at T12 and T0; systolic blood pressure increased in transmen (p=0.002). Transmen developed a pro-atherogenic lipoprotein profile, estrogen treatment in transwomen tended to result in improvements. Several metabolites indicating increased diabetes risk including plasma glucose were changed in transmen (p=0.025), with opposite changes in transwomen (p=0.002). Interestingly, at T1 apparent diabetes risk was lower in XX compared with XY individuals (p=0.002). CEC decreased in transwomen (p<0.01), while remaining unchanged in transmen. However, in both groups the strong positive association of apoA-I with cholesterol efflux observed at T0 was lost at T12. The results are consistent with increased cardiometabolic risk in transmen, while transwomen show beneficial changes early during gender-affirming hormone therapy. Sex chromosomes have less intrinsic effects. XY individuals and transmen display an increased apparent diabetes risk. Further research of cardiometabolic risk is needed for transgender individuals.

MASLD in persons with HIV is associated with high cardiometabolic risk as evidenced by altered advanced lipoprotein profiles and targeted metabolomics

BackgroundMetabolic dysfunction associated steatotic liver disease (MASLD) is associated with increased cardiovascular disease (CVD) risk in persons with HIV (PWH). The lipidomic and metabolomic alterations contributing to this risk are poorly understood. We aimed to characterize the advanced lipoprotein and targeted metabolomic profiles in PWH and assess if the presence and severity of MASLD influence these profiles.MethodsThis is a cross-sectional analysis of a prospectively enrolled multicenter cohort. PWH without alcohol abuse or known liver disease underwent vibration-controlled transient elastography for controlled attenuation parameter (CAP) and liver stiffness measurement (LSM). Lipidomic and metabolomic profiling was undertaken with nuclear magnetic resonance (NMR) spectroscopy. Hepatic steatosis was defined as CAP ≥ 263 dB/m and clinically significant fibrosis (CSF) as LSM ≥ 8 kPa. Logistic regression models assessed associations between MASLD, CSF and lipidomic and metabolic parameters.ResultsOf 190 participants (71% cisgender male, 96% on antiretroviral therapy), 58% had MASLD and 12% CSF. Mean (SD) age was 48.9 (12.1) years and body mass index (BMI) 29.9 (6.4) kg/m2. Compared to PWH without MASLD (controls), PWH with MASLD had lower HDL-C but higher total triglyceride, VLDL-C, branched-chain amino acids, GlycA, trimethylamine N-oxide levels, Lipoprotein-Insulin Resistance and Diabetes Risk Indices. There were no significant differences in these parameters between participants with MASLD with or without CSF. In a multivariable regression analysis, MASLD was independently associated with changes in most of these parameters after adjustment for age, gender, race/ethnicity, type 2 diabetes mellitus, BMI, and lipid lowering medications use.ConclusionsMASLD in PWH is independently associated with altered advanced lipoprotein and targeted metabolic profiles, indicating a higher CVD risk in this population.

Advanced lipid testing in children: a call for pediatric reference intervals

Abstract Introduction Abnormal serum lipid levels in childhood are associated with dyslipidemia and increased risk of cardiovascular disease in adulthood. High prevalence of childhood obesity in the US has increased concerns about the adverse effects of abnormal lipids in children, prompting recommendations for universal lipid screening in adolescents. While specialized analysis of lipoproteins by nuclear magnetic resonance (NMR) has been predominately used in adults with risk factors for CVD, our laboratory also receives pediatric samples for NMR testing, most commonly associated with diagnostic codes for hyperlipidemia and/or abnormal weight gain. Currently adult-based reference ranges for the NMR lipoprotein measurements are used in children. The objective of this pilot study was to compare lipoprotein profiles of healthy adults and children and to assess the impact of reference intervals for children on clinical interpretation of pediatric results. Methods Serum samples were collected from 60 healthy children, ages 1 – 17 years, and 148 healthy adults, ages 19 – 64 years old. NMR lipoprotein analysis was performed using the Axinon lipoFIT by NMR assay on a 600 MHz NMR (Bruker). Statistical analysis was conducted in Excel and GraphPad Prism. Reference intervals (RIs) were determined in EP Evaluator as the central 95% interval. Results The levels of atherogenic low-density lipoprotein particle number (LDL-P) and small LDL-P (sLDL-P) were significantly lower in children compared to adults: 783±222 vs 1212±412 nmol/L and 302±142 vs 498±306 nmol/L, respectively (p&amp;lt;0.00001). Additionally, LDL size (LDL-s) was significantly larger in children than adults (21.23±0.29 vs 21.06±0.44 nm, p=0.006), reflecting prevalence of less dense LDL-P in the former group. Pediatric samples also had lower number of anti-atherogenic high-density lipoprotein particles (HDL-P) compared to adults: 29.4±4.6 vs 33.5±4.6 µmol/L, p&amp;lt;0.00001. The significant differences in the number and size of lipoprotein particles between adults and children implies that currently used adult reference intervals might not be appropriate for evaluating pediatric NMR samples. Therefore, we estimated RIs for our heathy pediatric and adult cohorts and applied these RIs to our retrospective data of 618 samples from children 1-17 years old, which were submitted for NMR lipoprotein testing in recent years. The analysis showed that using the adult RIs, 37% and 27% of pediatric samples would not flag for abnormally elevated LDL-P and sLDL-P, respectively; but they would be flagged based on the RI derived from our pediatric cohort. Moreover, 12% pediatric samples flagged for low HDL-P would have normal HDL-P levels if pediatric RIs are used instead of adult RIs. Conclusions Use of adult reference intervals in children may result in misclassification of lipid status and underestimation or overestimation of dyslipidemia and CVD risk in children. This pilot study highlights the need for pediatric reference intervals to guide interpretation of advanced lipid testing in children.

NMR Insights into Lipoprotein Particles: analyzing correlations with traditional lipid measurements

Abstract Introduction Lipid metabolism plays a crucial role in various physiological processes. Lipid molecules are transported by lipoproteins, and the intricate involvement of lipoproteins in cardiovascular disease (CVD) is well-established, given their diverse size, density, and lipid composition. The emergence of Nuclear Magnetic Resonance (NMR) spectroscopy, a high-resolution analytical technique, promotes the assessment of lipoprotein particle numbers and sizes. Studies suggest that the measurement of total low-density lipoprotein particle numbers (LDL-P), small LDL-P (SLDL-P), and total high-density lipoprotein particle numbers (HDL-P) provides better evaluation of risk of CVD than enzymatic-based measurements of LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C). Our study examined the correlation between NMR-derived lipoprotein profiles and traditional cholesterol measurements in control and patient populations. Methods Fasting serum samples were collected from healthy male and female donors (n=148), ages 21-64 years. The analysis also included the results from &amp;gt;20,000 patients’ samples submitted to our laboratory for NMR lipid testing. We assessed LDL-P, SLDL-P, HDL-P, large HDL (LHDL-P), and HDL size (HDL-S) by NMR. In addition, total cholesterol (TC) and HDL-C were measured using traditional automated enzymatic assays (Roche Diagnostics); LDL-C was calculated. Statistical analyses, including Spearman correlation, were performed using GraphPad Prism software. Spearman coefficient (r) ≥0.75 indicated a strong correlation, r &amp;lt;0.5 indicated a weak correlation. Results HDL-C only moderately correlated with total HDL-P in samples collected from controls (rcontrols=0.52) and patients (rpatients=0.68), while showing better correlation with LHDL-P (rcontrols=0.90, rpatients=0.89). Traditional LDL-C strongly correlated with total LDL-P (rcontrols=0.76, rpatients=0.81), but showed only weak correlation with SLDL-P (rcontrols=0.42, rpatients=0.28), which is considered more atherogenic and predictive of CVD risk than LDL-C or total LDL-P. Interestingly, among various lipoprotein parameters, SLDL-P correlated the strongest with HDL-S in both study populations (rcontrols=-0.87, rpatients=-0.84). Samples with higher number of SLDL-P also had smaller size of HDL-P, although the number of total HDL-P did not differ between high vs low SLDL-P samples. In contrast, only moderate negative correlation was observed between SLDL-P and traditional HDL-C (rcontrols=-0.74, rpatients=-0.68), suggesting that the size of HDL particles might add value in evaluating CVD risk. Conclusion The NMR technology has advantage over traditional measurements in stratifying an individual’s lipoprotein milieu. It provides insights into the number of small LDL particles and size of HDL particles, which are not included in standard lipid testing and may allow for more individualized patient care. Incorporation of lipoprotein size and particle number in clinical guidelines may help physicians with assessment CVD risk and treatment monitoring.

The Composition of the HDL Particle and Its Capacity to Remove Cellular Cholesterol Are Associated with a Reduced Risk of Developing Active Inflammatory Rheumatoid Arthritis.

In rheumatoid arthritis (RA), the risk of cardiovascular death is 50% higher compared to the general population. This increased risk is partly due to the systemic inflammation characteristic of RA and changes in the lipoprotein profiles. This study investigated plasma lipid levels, lipid ratios, and the composition and functionality of high-density lipoprotein (HDL) in control individuals and RA subjects based on the disease's inflammatory score (DAS28). This study included 50 control (CTR) individuals and 56 subjects with RA, divided into remission/low-activity disease (DAS28 < 3.2; n = 13) and active disease (DAS28 ≥ 3.2; n = 43). Plasma lipids (total cholesterol, TC; triglycerides, TG) and the HDL composition (TC; TG; phospholipids, PL) were determined using enzymatic methods; apolipoprotein B (apoB) and apoA-1 were measured by immunoturbidimetry. HDL-mediated cholesterol efflux and anti-inflammatory activity were assessed in bone marrow-derived macrophages. Comparisons were made using the Mann-Whitney test, and binary logistic regression was used to identify the predictors of active RA. A p-value < 0.05 was considered significant. TC, HDLc, and the TC/apoB ratio were higher in RA subjects compared to the CTR group. Subjects with active disease exhibited higher levels of TG and the TG/HDLc ratio and lower levels of HDLc, the TG/apoB ratio, TC, and apoA-1 in HDL particles compared to those with remission/low-activity RA. Increased levels of HDLc [odds ratio (OR) 0.931, 95% CI = 0.882-0.984], TC/apoB (OR 0.314, 95% CI = 0.126-0.78), HDL content in TC (OR 0.912, 95% CI = 0.853-0.976), PL (OR 0.973, 95% CI = 0.947-1.000), and apoA-1 (OR 0.932, 95% CI = 0.882-0.985) were associated with a decreased risk of active disease, but BMI (OR 1.169, 95% CI = 1.004-1.360) and TG (OR 1.031, 95% CI = 1.005-1.057) were positively associated with active disease. A reduction in HDL-mediated cholesterol efflux increased the OR for active RA by 26.2%. The plasma levels of HDLc, along with the composition and functionality of HDL, influence the inflammatory score in RA and may affect the development of cardiovascular disease.

Omega‐3 Marine Fatty Acid Supplementation to Healthy Subjects Interacts With Moderate Physical Activity to Provide a Cardiovascular Healthier Lipoprotein Subclass Profile

ABSTRACTThis work investigates the impact of marine omega‐3 and physical activity and their interaction on cardiometabolic health as expressed by the serum lipoprotein profile. Using an experimental design that allows for the possibility of interaction, we performed a 6‐week intervention on 44 middle‐aged women living in Western Norway. The women were randomly divided into four groups: one control group with no intervention, a second group performing sessions of moderate intensity three times per week, a third group taking daily supplements of omega‐3 marine fatty acids, and a fourth group combining the interventions for Groups 2 and 3. The difference in the lipoprotein profiles after the intervention from baseline were assessed for statistical significance by comparing groups 2, 3 and 4 with Group 1 using two‐tailed t‐test corrected for multiple testing and selectivity ratios calculated from the discriminatory component in validated partial least squares discriminant models. The results from the univariate and multivariate analyses were qualitatively equivalent: Only the women combining moderate physical activity and omega‐3 supplementation, revealed statistically significant differences in their lipoprotein profile compared to the nonintervention control group. The pattern of change in the lipoprotein profile is associated with improved cardiometabolic health. Use of the design matrix to predict this pattern revealed that the interaction between omega‐3 supplementation and physical activity played a major role in inducing this change. The recognition of the influence of this interaction may be a step towards resolving the long‐lasting debate of the role played by omega‐3 for preventing cardiovascular unhealth.

5123 Remission of Antibodies Blocking the Insulin Receptor Reduces Atherogenicity of LDL Particles but Increases HDL Particle Atherogenicity

Abstract Disclosure: M. Hwang: None. R. Shamburek: None. M. Lightbourne: None. M. Sampson: None. A. Remaley: None. B. Abel: None. R.J. Brown: None. Background: Type B insulin resistance syndrome (TBIR) is a rare autoimmune disorder defined by the presence of autoantibodies against the insulin receptor, usually in the context of systemic autoimmune diseases such as lupus. In TBIR, insulin signaling is disrupted at the receptor-level, resulting in failure of insulin to both suppress hepatic glucose production and to stimulate de novo lipogenesis. This leads to a phenotype of extreme insulin resistance (IR) and hyperglycemia without dyslipidemia. IR and hyperglycemia resolve when remission of the autoantibody is induced by immunosuppression. Given the known association between IR and cardiovascular disease (CVD), we sought to compare biomarkers of CVD risk using lipoprotein particles measured by Nuclear Magnetic Resonance (NMR) in patients with TBIR during their active disease state vs remission. Methods: Patients with TBIR (N=14) had fasting labs including NMR lipoprotein profiles (analyzed using LP4 deconvolution algorithm) during active disease (positive antibodies to the insulin receptor and severe IR) and remission (defined by discontinuation of insulin or amelioration of hyperglycemia). Particle size (nm) and concentration of subclasses by size were measured for low-density lipoprotein (LDL) particles (nmol/L) and high-density lipoprotein (HDL) particles (umol/L). Results: Upon remission from TBIR, there were large decreases in hemoglobin A1c (from 10.9±3.0% to 6.1±1.1%, p&amp;lt;0.001) and insulin (from 1000.0 (715.9, 1000.0) mcU/mL to 16.8 (8.1, 39.2) mcU/mL, normal 2.6-24.9 mcU/mL, p&amp;lt;0.001), and increases in BMI (from 21.8±3.5 to 28.6±7.4 kg/m2, p&amp;lt;0.01), C3 (from 76±27 to 114±20 mg/dL, normal 82-185 mg/dL, p&amp;lt;0.01), and C4 (from 16±8 to 25±9 mg/dL, normal 15-53 mg/dL, p&amp;lt;0.01). After remission of TBIR, LDL profiles became less atherogenic: small LDL particle concentration decreased (from 523.4±170.2 to 362.8±119.7, normal 63.8-1719.6, p&amp;lt;0.01) and LDL particle size increased (from 20.6±0.5 to 21.2±0.3, normal 19.9 -21.6, p&amp;lt;0.01). By contrast, HDL profiles became more atherogenic after remission of TBIR: small HDL particle concentration increased (from 4.6±2.6 to 8.2±4.3, normal 6.6-19.3, p&amp;lt;0.01); the largest HDL particle concentration decreased (from 1.5±0.8 to 0.7±0.7, normal 0-1.2, p&amp;lt;0.01), and HDL particle size decreased (from 10.3±0.4 to 9.6±0.5, normal 8.4-9.9, p&amp;lt;0.001). Conclusions: Active TBIR is a pro-inflammatory state characterized by excess consumption of C3 and C4. Inflammation may contribute to an unfavorable LDL particle profile that improves after remission. However, lack of insulin signaling through the insulin receptor during active TBIR likely leads to an anti-atherogenic HDL profile that returns to normal levels when insulin signaling is restored after remission. Future studies will further investigate the role of insulin resistance and inflammation in CVD risk. Presentation: 6/3/2024

A-227 One Step Toward Implementation of Advanced Lipoprotien Testing in Children: A Pilot Study on Pediatric Reference Ranges

Abstract Background Abnormal serum lipid levels in childhood are associated with dyslipidemia and increased risk of cardiovascular disease in adulthood. High prevalence of childhood obesity in the US has increased concerns about the adverse effects of abnormal lipids in children, prompting recommendations for universal lipid screening in adolescents. While specialized analysis of lipoproteins by nuclear magnetic resonance (NMR) has been predominately used in adults with risk factors for CVD, our laboratory also receives pediatric samples for NMR testing, most commonly associated with diagnostic codes for hyperlipidemia and/or abnormal weight gain. Currently adult-based reference ranges for the NMR lipoprotein measurements are used in children. The objective of this pilot study was to compare lipoprotein profiles of healthy adults and children and to assess the impact of reference intervals for children on clinical interpretation of pediatric results. Methods Serum samples were collected from 60 healthy children, ages 1 - 17 years, and 148 self-identified healthy adults, ages 19 - 64 years old. NMR lipoprotein analysis was performed using the Axinon lipoFIT by NMR assay on a 600 MHz NMR (Bruker). Statistical analysis was conducted in Excel and Graph Pad Prism. Reference intervals (RIs) were determined in EP Evaluator as the central 95% interval. Results The levels of atherogenic low-density lipoprotein particle number (LDL-P) and small LDL-P (sLDL-P) were significantly lower in children compared to adults: 783±222 vs 1212±412 nmol/L and 302±142 vs 498±306 nmol/L, respectively (p&amp;lt;0.00001). Additionally, LDL size (LDL-s) was significantly larger in children than adults (21.23±0.29 vs 21.06±0.44 nm, p=0.006), reflecting prevalence of less dense LDL-P in the former group. Pediatric samples also had lower number of anti-atherogenic high-density lipoprotein particles (HDL-P) compared to adults: 29.4±4.6 vs 33.5±4.6 µmol/L, p&amp;lt;0.00001. The significant differences in the number and size of lipoprotein particles between adults and children implies that currently used adult reference intervals might not be appropriate for evaluating pediatric NMR samples. Therefore, we estimated RIs for our heathy pediatric and adult cohorts and applied these RIs to our retrospective data of 618 samples from children 1-17 years old, which were submitted for NMR lipoprotein testing in recent years. The analysis showed that using the adult RIs, 37% and 27% of pediatric samples would not flag for abnormally elevated LDL-P and sLDL-P, respectively; but they would be flagged based on the RI derived from our pediatric cohort. Moreover, 12% pediatric samples flagged for low HDL-P would have normal HDL-P levels if pediatric RIs are used instead of adult RIs. Conclusions Use of adult reference intervals in children may result in misclassification of lipid status and underestimation or overestimation of dyslipidemia and CVD risk in children. This pilot study highlights the need for pediatric reference intervals to guide interpretation of advanced lipid testing in children.

Clinical prediction of wound re-epithelisation outcomes in non-severe burn injury using the plasma lipidome

Whilst wound repair in severe burns has received substantial research attention, non-severe burns (<20% total body surface area) remain relatively understudied, despite causing considerable physiological impact and constituting most of the hospital admissions for burns. Early prediction of healing outcomes would decrease financial and patient burden, and aid in preventing long-term complications from poor wound healing. Lipids have been implicated in inflammation and tissue repair and may play essential roles in burn wound healing. In this study, plasma samples were collected from 20 non-severe burn patients over 6 weeks from admission, including surgery, and analysed by liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance spectroscopy to detect 850 lipids and 112 lipoproteins. Orthogonal projections to latent structures-discriminant analysis was performed to identify changes associated with re-epithelialisation and delayed re-epithelisation.We demonstrated that the lipid and lipoprotein profiles at admission could predict re-epithelisation outcomes at 2 weeks post-surgery, and that these discriminatory profiles were maintained up to 6 weeks post-burn. Inflammatory markers GlycB and C-reactive protein indicated divergent systemic responses to the burn injury at admission. Triacylglycerols, diacylglycerols and low-density lipoprotein subfractions were associated with delayed wound closure (p-value <0.02, Cliff’s delta >0.7), whilst high-density lipoprotein subfractions, phosphatidylinositols, phosphatidylcholines, and phosphatidylserines were associated with re-epithelisation at 2 weeks post-surgery (p-value <0.01, Cliff’s delta <-0.7). Further model validation will potentially lead to personalised intervention strategies to reduce the risk of chronic complications post-burn injury.

Untargeted Lipidomics Reveals Novel HDL Metabotypes and Lipid-Clinical Correlates

Plasma high-density lipoprotein (HDL), originally studied for its role in lipid transport, is now appreciated to have wide-ranging biological functions that become defective during disease. While >200 lipids have collectively been detected in HDL, published HDL lipidomic analyses in different diseases have commonly been targeted to prespecified subsets of lipids. Here, we report the results of untargeted lipidomic analysis of HDL isolated from 101 subjects referred for computed tomographic coronary imaging for whom multiple additional clinical and lipoprotein metadata were measured. Unsupervised clustering of the total HDL lipidome revealed that the subjects fell into one of two discrete groups, herein referred to as HDL ‘metabotypes’. Subjects in metabotype 1 were likelier to be female and tended to have a less atherogenic lipoprotein profile, higher HDL cholesterol efflux capacity (CEC), and lower-grade non-calcified burden on coronary imaging than metabotype 2 counterparts. Specific lipids were relatively enriched in metabotype 1 HDL. Linear modeling revealed that several of these lipids were positively associated with CEC, statin use, HDL size, and HDL particle number, and positively correlated with HDL apolipoprotein A-1, suggesting that they may be informative HDL biomarkers. Taken together, we posit a novel, clinically relevant categorization for HDL revealed by systems biology.

Serum lipid and lipoprotein profiles and their association with intraocular pressure in primary open-angle glaucoma: an observational cross-sectional study in the Chinese population

BackgroundGlaucoma is a leading cause of vision impairment and permanent blindness. Primary open-angle glaucoma (POAG) is a prominent type of primary glaucoma; however, its cause is difficult to determine. This study aimed to analyze the serum lipid profile of Chinese POAG patients and assess its correlation with intraocular pressure (IOP).MethodsThe study included 1,139, 1,248, and 356 Chinese individuals with POAG, primary angle closure glaucoma (PACG), and controls, respectively. Peripheral whole blood samples were collected at the time of diagnosis. Enzymatic colorimetry was used to determine serum levels of different lipids: high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides, cholesterol, and very low-density lipoproteins (VLDL). Additionally, immunoturbidimetry was used to quantify serum levels of apolipoproteins A (APOA), B (APOB), E (APOE), and lipoprotein A [Lp(a)], while intraocular pressure (IOP) was measured in all patients with POAG.ResultsAfter adjusting for age and sex, patients with POAG exhibited elevated serum levels of VLDL, APOA, and APOE but mitigated cholesterol levels compared with the control participants. Significantly lower serum triglyceride, VLDL, and Lp(a) levels were found in patients with PACG than in control participants. Serum cholesterol (P = 0.019; β = -0.75, 95% confidence interval [CI]: -1.38 – -0.12) and HDL levels (P < 0.001; β = -2.91, 95% CI: -4.58 – -1.25) were inversely linked to IOP in patients with POAG, after adjusting for age, sex, and ocular metrics. In addition, serum Lp(a) levels were correlated with the average IOP (P = 0.023; β = -0.0039, 95% CI: -0.0073 – -0.006) and night peak (P = 0.027; β = -0.0061, 95% CI: -0.0113 – -0.0008) in patients with POAG.ConclusionsSignificantly different serum lipid and lipoprotein profiles were observed in POAG and PACG patients. This study highlighted the differences in serum lipid and lipoprotein levels among Chinese POAG patients and their relationship with IOP and IOP fluctuation. Serum lipid and lipoprotein profiles should be considered while evaluating glaucoma risk.

Metabolomic signature identifies HDL and apolipoproteins as potential biomarker for systemic sclerosis with interstitial lung disease

BackgroundHigh-density lipoproteins (HDL) affect endothelial functions such as the expression of endothelial cell adhesion molecules and exert anti-apoptotic/-thrombotic functionalities. Therefore, profound analysis of lipoproteins may unveil biomarkers for (micro-)vasculopathy in systemic sclerosis (SSc) and mortality determining disease manifestations like interstitial lung disease (SSc-ILD). Because nuclear magnetic resonance (NMR) spectroscopy provides a wide range of lipoprotein parameters beyond the capabilities of classical analyses it has been used herein to examine lipoprotein profiles in SSc. MethodsTo detect the metabolic and lipidomic profile serum samples from clinically well-characterized SSc patients (n = 100) and age-and sex-matched healthy controls (n = 40) were analyzed by 1H NMR spectroscopy using Bruker's in-vitro diagnostic research (IVDr) protocol. Statistical analyses were performed to validate significant findings and to search for associations between lipoproteins and clinical phenotypes. ResultsPatients with SSc-ILD and lung fibrosis displayed reduced HDL levels. Furthermore, a reduction in apolipoprotein A1 + A2 and its HDL fractions reflected a distinct lipoprotein profile for SSc-ILD patients. This association was independent of potential clinical confounders for dyslipidemia. Notably, in SSc-ILD HDL levels correlate with FVC (forced vital capacity), DLCO (diffusion capacity of the lungs for carbon monoxide), and the modified Rodnan-Skin-Score. ConclusionThese results suggest HDL and its lipoproteins may be considered as potential new biomarkers for SSc-ILD. Immune-mediated HDL effects on the endothelium facilitate microvasculopathy - one of the pathophysiological hallmarks in SSc. Therefore, a closer prospective evaluation of the capability of HDL-determination and its lipoproteins regarding a more individualized evaluation of SSc-ILD is warranted.

Nutritional Composition and Effect of Loquat Fruit (Eriobotrya japonica L. var. Navela) on Lipid Metabolism and Liver Steatosis in High-Fat High-Sucrose Diet-Fed Mice.

Loquat (Eriobotrya japonica L.) is a popular fruit known for its sweet and slightly tangy flavor, which is widely consumed both fresh and in various processed forms. This study aimed to analyze the biochemical composition of loquat juice and investigate its metabolic benefits in mice fed a high-fat/high-sucrose diet (HFSD). Mice were fed either a standard diet or an HFSD and received or not the loquat juice at 4 or 8 mL/kg body weight for 8 weeks. Body weight, food efficiency ratio, plasma lipoprotein profile, plasma glucose, and lipid indices were monitored throughout the experiment. At the end of the experiment, additional assessments were performed, including lipid content measurements in liver, adipose tissue, bile, and feces; hepatic antioxidant enzyme activities (superoxide dismutase and catalase); hepatic malondialdehyde content; plasma biomarkers of liver injury; liver histology; and organ relative weight. Feeding mice with the HFSD resulted in a significant perturbation in lipid and glucose metabolism, obesity, liver steatosis, and oxidative stress-related enzymes. However, the concomitant administration of loquat juice significantly corrected this imbalance. Fresh loquat juice is low in fat and protein, moderately sugary, and energetically light; however, it is rich in minerals, vitamin C, and various phytochemicals compounds, such as phenolic acids, flavonoids, and carotenoids. The loquat juice could be considered a functional food and could be valorized through the extraction of active substances and their use as food supplements to prevent lipid metabolism disorders and the resulting health complications.

Aerobic Exercise Training Protects Against Insulin Resistance, Despite Low-Sodium Diet-Induced Increased Inflammation and Visceral Adiposity.

Dietary sodium restriction increases plasma triglycerides (TG) and total cholesterol (TC) concentrations as well as causing insulin resistance and stimulation of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system. Stimulation of the angiotensin II type-1 receptor (AT1) is associated with insulin resistance, inflammation, and the inhibition of adipogenesis. The current study investigated whether aerobic exercise training (AET) mitigates or inhibits the adverse effects of dietary sodium restriction on adiposity, inflammation, and insulin sensitivity in periepididymal adipose tissue. LDL receptor knockout mice were fed either a normal-sodium (NS; 1.27% NaCl) or a low-sodium (LS; 0.15% NaCl) diet and were either subjected to AET for 90 days or kept sedentary. Body mass, blood pressure (BP), hematocrit, plasma TC, TG, glucose and 24-hour urinary sodium (UNa) concentrations, insulin sensitivity, lipoprotein profile, histopathological analyses, and gene and protein expression were determined. The results were evaluated using two-way ANOVA. Differences were not observed in BP, hematocrit, diet consumption, and TC. The LS diet was found to enhance body mass, insulin resistance, plasma glucose, TG, LDL-C, and VLDL-TG and reduce UNa, HDL-C, and HDL-TG, showing a pro-atherogenic lipid profile. In periepididymal adipose tissue, the LS diet increased tissue mass, TG, TC, AT1 receptor, pro-inflammatory macro-phages contents, and the area of adipocytes; contrarily, the LS diet decreased anti-inflammatory macrophages, protein contents and the transcription of genes related to insulin sensitivity. The AET prevented insulin resistance, but did not protect against dyslipidemia, adipose tissue pro-inflammatory profile, increased tissue mass, AT1 receptor expression, TG, and TC induced by the LS diet.

Lipoprotein metabolism mediates hematopoietic stem cell responses under acute anemic conditions

Hematopoietic stem cells (HSCs) react to various stress conditions. However, it is unclear whether and how HSCs respond to severe anemia. Here, we demonstrate that upon induction of acute anemia, HSCs rapidly proliferate and enhance their erythroid differentiation potential. In severe anemia, lipoprotein profiles largely change and the concentration of ApoE increases. In HSCs, transcription levels of lipid metabolism-related genes, such as very low-density lipoprotein receptor (Vldlr), are upregulated. Stimulation of HSCs with ApoE enhances their erythroid potential, whereas HSCs in Apoe knockout mice do not respond to anemia induction. VldlrhighHSCs show higher erythroid potential, which is enhanced after acute anemia induction. VldlrhighHSCs are epigenetically distinct because of their low chromatin accessibility, and more chromatin regions are closed upon acute anemia induction. Chromatin regions closed upon acute anemia induction are mainly binding sites of Erg. Inhibition of Erg enhanced the erythroid differentiation potential of HSCs. Our findings indicate that lipoprotein metabolism plays an important role in HSC regulation under severe anemic conditions.