Elevated high-density lipoprotein in adolescents with Type 1 diabetes is associated with endothelial dysfunction in the presence of systemic inflammation.

AIMS: High-density lipoprotein (HDL) function may be altered in patients with chronic disease, transforming the particle from a beneficial vasoprotective molecule to a noxious pro-inflammatory equivalent. Adolescents with Type 1 diabetes often have elevated HDL, but its vasoprotective properties and relationship to endothelial function have not been assessed. METHODS AND RESULTS: Seventy adolescents with Type 1 diabetes (age 10-17 years) and 30 age-matched healthy controls supplied urine samples for the measurement of early renal dysfunction (albumin:creatinine ratio; ACR), blood samples for the assessment of cardiovascular risk factors (lipid profiles, HDL functionality, glycaemic control, and inflammatory risk score), and had their conduit artery endothelial function tested using flow-mediated dilation (FMD). HDL-c levels (1.69 ± 0.41 vs. 1.44 ± 0.29mmol/L; P < 0.001), and glycated haemoglobin (HbA1c) (8.4 ± 1.2 vs. 5.4 ± 0.2%; P < 0.001) were increased in all patients compared with controls. However, increased inflammation and HDL dysfunction were evident only in patients who also had evidence of early renal dysfunction (mean ± standard deviation for high-ACR vs. low-ACR and healthy controls: inflammatory risk score 11.3 ± 2.5 vs. 9.5 ± 2.4 and 9.2 ± 2.4, P < 0.01; HDL-mediated nitric-oxide bioavailability 38.0 ± 8.9 vs. 33.3 ± 7.3 and 25.0 ± 7.7%, P < 0.001; HDL-mediated superoxide production 3.71 ± 3.57 vs. 2.11 ± 3.49 and 1.91 ± 2.47nmol O2 per 250 000 cells, P < 0.05). Endothelial function (FMD) was impaired only in those who had both a high inflammatory risk score and high levels of HDL-c (P < 0.05). CONCLUSION: Increased levels of HDL-c commonly observed in individuals with Type 1 diabetes may be detrimental to endothelial function when accompanied by renal dysfunction and chronic inflammation.

HDL in children with CKD promotes endothelial dysfunction and an abnormal vascular phenotype.

Endothelial dysfunction begins in early CKD and contributes to cardiovascular mortality. HDL is considered antiatherogenic, but may have adverse vascular effects in cardiovascular disease, diabetes, and inflammatory conditions. The effect of renal failure on HDL properties is unknown. We studied the endothelial effects of HDL isolated from 82 children with CKD stages 2-5 (HDL(CKD)), who were free of underlying inflammatory diseases, diabetes, or active infections. Compared with HDL from healthy children, HDL(CKD) strongly inhibited nitric oxide production, promoted superoxide production, and increased vascular cell adhesion molecule-1 expression in human aortic endothelial cells, and reduced cholesterol efflux from macrophages. The effects on endothelial cells correlated with CKD grade, with the most profound changes induced by HDL from patients on dialysis, and partial recovery observed with HDL isolated after kidney transplantation. Furthermore, the in vitro effects on endothelial cells associated with increased aortic pulse wave velocity, carotid intima-media thickness, and circulating markers of endothelial dysfunction in patients. Symmetric dimethylarginine levels were increased in serum and fractions of HDL from children with CKD. In a longitudinal follow-up of eight children undergoing kidney transplantation, HDL-induced production of endothelial nitric oxide, superoxide, and vascular cell adhesion molecule-1 in vitro improved significantly at 3 months after transplantation, but did not reach normal levels. These results suggest that in children with CKD without concomitant disease affecting HDL function, HDL dysfunction begins in early CKD, progressing as renal function declines, and is partially reversed after kidney transplantation.

Impact of surface nano-textured stainless steel prepared by focused ion beam on endothelial cell growth.

The modification of stent surfaces with nano-structures has the potential for limiting late stent restenosis. We report here the patterning of 316L austentitic stainless steel with arrays of nano-pits of two nominal diameters: 120 and 180 nm. These nano-textured surfaces were prepared by focused ion beam milling. The influence of the ion beam current on the nano-features was investigated by scanning electron and atomic force microscopies. The optimum ion beam currents were 280 pA for 120 nm nano-pits and 920 pA for 180 nm nano-pits. The depths of the nano-pits formed were (65 +/- 24) nm (120 nm) and (84 +/- 36) nm (180 nm). This wide distribution of the depths is due to the polycrystalline nature of 316 L stainless steel, which has a strong influence on the milling rates. Endothelial cells were grown in vitro on these substrates for 1, 3 and 5 days. The cells were viable for the duration of the cell culture on the nano-textured substrates. There was no significant difference in the adhesion and the proliferation based on the nano-pit diameter.

COVID-19-associated hyperinflammation and escalation of patient care: a retrospective longitudinal cohort study.

BACKGROUND: A subset of patients with severe COVID-19 develop a hyperinflammatory syndrome, which might contribute to morbidity and mortality. This study explores a specific phenotype of COVID-19-associated hyperinflammation (COV-HI), and its associations with escalation of respiratory support and survival. METHODS: In this retrospective cohort study, we enrolled consecutive inpatients (aged ≥18 years) admitted to University College London Hospitals and Newcastle upon Tyne Hospitals in the UK with PCR-confirmed COVID-19 during the first wave of community-acquired infection. Demographic data, laboratory tests, and clinical status were recorded from the day of admission until death or discharge, with a minimum follow-up time of 28 days. We defined COV-HI as a C-reactive protein concentration greater than 150 mg/L or doubling within 24 h from greater than 50 mg/L, or a ferritin concentration greater than 1500 µg/L. Respiratory support was categorised as oxygen only, non-invasive ventilation, and intubation. Initial and repeated measures of hyperinflammation were evaluated in relation to the next-day risk of death or need for escalation of respiratory support (as a combined endpoint), using a multi-level logistic regression model. FINDINGS: We included 269 patients admitted to one of the study hospitals between March 1 and March 31, 2020, among whom 178 (66%) were eligible for escalation of respiratory support and 91 (34%) patients were not eligible. Of the whole cohort, 90 (33%) patients met the COV-HI criteria at admission. Despite having a younger median age and lower median Charlson Comorbidity Index scores, a higher proportion of patients with COV-HI on admission died during follow-up (36 [40%] of 90 patients) compared with the patients without COV-HI on admission (46 [26%] of 179). Among the 178 patients who were eligible for full respiratory support, 65 (37%) met the definition for COV-HI at admission, and 67 (74%) of the 90 patients whose respiratory care was escalated met the criteria by the day of escalation. Meeting the COV-HI criteria was significantly associated with the risk of next-day escalation of respiratory support or death (hazard ratio 2·24 [95% CI 1·62-2·87]) after adjustment for age, sex, and comorbidity. INTERPRETATION: Associations between elevated inflammatory markers, escalation of respiratory support, and survival in people with COVID-19 indicate the existence of a high-risk inflammatory phenotype. COV-HI might be useful to stratify patient groups in trial design. FUNDING: None.

Anti-inflammatory treatment improves high-density lipoprotein function in rheumatoid arthritis.

OBJECTIVE: Patients with rheumatoid arthritis (RA) are at increased cardiovascular risk. Recent studies suggest that high-density lipoprotein (HDL) may lose its protective vascular phenotype in inflammatory conditions. However, the effects of common anti-inflammatory treatments on HDL function are not yet known. METHODS: We compared the function of HDL in 18 patients with RA and 18 matched healthy controls. Subsequently, patients were randomised to (methotrexate+infliximab (M+I) (5 mg/kg)) or methotrexate+placebo (M+P) infusions for 54 weeks. At week 54 and thereafter, all patients received infliximab therapy until completion of the trial (110 weeks), enabling assessment of the impact of 1 year of infliximab therapy in all patients. HDL functional properties were assessed at baseline, 54 weeks and 110 weeks by measuring the impact on endothelial nitric oxide (NO) bioavailability and superoxide production (SO), paraoxonase activity (PON-1) and cholesterol efflux. RESULTS: All HDL vascular assays were impaired in patients compared with controls. After 54 weeks, NO in response to HDL was significantly greater in patients who received M+I compared with those who received M+P. Endothelial SO in response to HDL was reduced in both groups, but PON-1 and cholesterol efflux remained unchanged. All vascular measures improved compared with baseline after ≥1 infliximab therapy in the analysis at 110 weeks. No significant trend was noted for cholesterol efflux. CONCLUSIONS: HDL function can be improved with anti-inflammatory treatment in patients with RA. The M+I combination was superior to the M+P alone, suggesting that the tumour necrosis factor-α pathway may have a role in HDL vascular properties.

Reproducibility and biological variability of HDL's vascular functional assays.

BACKGROUND: Recent failures of clinical trials promoting HDL-elevating therapies have prompted research groups to focus on its functional activity in disease. Endothelial effects of HDL can be measured with in vitro cell assays. The reproducibility and biological relevance of these assays have not been explored both in healthy individuals and those at increased cardiovascular (CV) risk. METHODS: HDL dependent nitric oxide (NO) bioavailability, superoxide (SO) production and serum paraoxonase-1 (PON-1) activity were measured in 35 healthy adults (34.37 24-49) and 8 patients (43.56 37-49) suffering from a chronic inflammatory condition (periodontitis-PD). Assay reproducibility was assessed by independent technicians on consecutive days to determine inter and intra analyser variability for each assay. The 35 healthy individuals were further divided into young (n = 16) and middle aged (n = 19) groups and compared with regards to HDL functions. Within-subject biological variation of HDL function was determined in a sub-group of 25 healthy volunteers at intervals of one day and 1 month, and in 8 patients at intervals of one day and 1 week. Power curves were also generated to estimate the number of patients that would be required for HDL functional assays in a cross-over and parallel study design. RESULTS: NO bioavailability was the most reproducible assay in healthy adults (coefficient of variation = 1.72%, 1.92 - intra and inter respectively) and PD patients (CV = 4.4% and 5.5%). All measures demonstrated no statistical difference between young and healthy middle aged population. No single assay demonstrated significant variations over time, indicating that within patient variations are negligible. Our power curves for NO bioavailability and PON-1 activity suggest that low number of patients will be required to detect significant differences in HDL function in a cross over and parallel study design. CONCLUSION: This study suggests that in vitro HDL functional assays are reliable and can be used to assess HDL functionality in healthy and diseased populations. NO bioavailability was the most reproducible assay, but PON-1 activity remains the most practical for application in clinical trials due to its capacity for scale.

Structural and functional changes in HDL with low grade and chronic inflammation.

OBJECTIVE: HDL functionality has been shown to be impaired in inflammatory conditions, including coronary artery disease. The present study aims to determine the impact of low grade and acute inflammation on HDL function and structure. APPROACH AND RESULTS: i) The endothelial protective effects of HDL were compared between 26 periodontal patients and 26 age and sex matched controls by measuring paraoxonase activity in serum and nitric oxide bioavailability and superoxide production in endothelial cells. Paraoxonase activity and nitric oxide bioavailability were reduced, while superoxide production was increased (p<0.01) in periodontal patients compared to controls. ii) HDL function, including cholesterol efflux and vascular cell adhesion molecule-1 expression, was subsequently measured in the periodontal patients following an inflammatory stimulus. There was an acute deterioration in HDL's endothelial protective function, without change in cholesterol efflux, after 24h (p<0.01 for all). These functional changes tracked increases of inflammatory markers and altered HDL composition. Finally, HDL function returned to baseline levels after resolution of inflammation. CONCLUSION: This study demonstrates that even minor alterations in systemic inflammation can impair the endothelial protective effects of HDL. These functional changes were independent of cholesterol efflux and were associated with remodeling of the HDL proteome. All measures of HDL's endothelial protective functions recovered with resolution of inflammation. These findings suggest that HDL dysfunction may represent a novel mechanism linking inflammation with progression of atheroma.