Designer high-density lipoprotein particles enhance endothelial barrier function and suppress inflammation

ApoM-bound S1P acts via endothelial S1PR1 to suppress choroidal neovascularization and vascular leakage

Neovascular age-related macular degeneration (nAMD) is a major cause of vision loss worldwide. Current standard of care is repetitive intraocular injections of vascular endothelial growth factor (VEGF) inhibitors, although responses may be partial and non-durable. We report that circulating sphingosine 1-phosphate (S1P) carried by apolipoprotein M (ApoM) acts through the endothelial S1P receptor 1 (S1PR1) to suppress choroidal neovascularization (CNV) in mouse laser-induced CNV, modeling nAMD. In humans, low plasma ApoM levels were associated with increased choroidal and retinal pathology. Additionally, endothelial S1pr1 knockout and overexpressing transgenic mice showed increased and reduced CNV lesion size, respectively. Systemic administration of ApoM-Fc, an engineered S1P chaperone protein, not only attenuated CNV to an equivalent degree as anti-VEGF antibody treatment but also suppressed pathological vascular leakage. We suggest that modulating circulating ApoM-bound S1P action on endothelial S1PR1 provides a novel therapeutic strategy to treat nAMD.

ApoM and Major Adverse Cardiovascular Events in Chronic Kidney Disease: A Prospective Cohort Study

BACKGROUND

Cardiovascular disease is the leading cause of mortality in patients with chronic kidney disease (CKD). APOM plays a critical role in reverse cholesterol transport by facilitating the formation of pre-β-HDL (high-density lipoprotein) and enabling the binding of S1P (sphingosine-1-phosphate) to HDL, a complex involved in several antiatherogenic processes. In this study, we sought to investigate the potential association between plasma APOM levels and the risk of adverse cardiovascular outcomes in individuals with CKD.

METHODS

Plasma APOM levels were quantified using a sandwich ELISA-based assay. Plasma S1P levels were measured by high-performance liquid chromatography. The primary end point was a composite of major adverse cardiovascular events (MACE) and all-cause mortality.

RESULTS

In this secondary analysis of the CARE FOR HOMe study (Cardiovascular and Renal Outcome in CKD 2-4 Patients-The Fourth Homburg Evaluation), 463 nondialysis patients with CKD stages G2 to G4 were included. Plasma APOM levels exhibited a significant inverse association with the risk of MACE (standardized hazard ratio, 0.60 [95% CI, 0.49-0.75]; P<0.001) and all-cause mortality (standardized hazard ratio, 0.63 [95% CI, 0.48-0.83]; P<0.001). This inverse association with MACE remained robust after adjusting for established cardiovascular and renal risk factors. These findings were further corroborated in an independent cohort of 822 patients with CKD from the Copenhagen CKD study. Plasma S1P levels showed an inverse association with MACE in univariable analyses; however, this relationship lost statistical significance after multivariable adjustments.

CONCLUSIONS

Our findings demonstrate a significant association between low plasma APOM levels and an increased risk of MACE in patients with CKD. These results suggest that APOM may play a role in cardiovascular protection in this vulnerable population.

Inflammatory lipid biomarkers and transplant-free mortality risk in hepatitis B-related cirrhosis and hepatic encephalopathy

Objective

Inflammatory reactions and dyslipidemia are associated with the pathogenesis and prognosis of hepatitis B virus-related cirrhosis. We aimed to assess the predictive ability of these parameters in patients with hepatitis B virus-related cirrhosis and overt hepatic encephalopathy (HBV-related OHE).

Design

We conducted an analysis of 1,404 participants diagnosed with HBV-related OHE between January 2008 and July 2023. The prognostic significance of the neutrophil-to-high-density lipoprotein cholesterol (HDL-C) ratio (NHR), lymphocyte-to-HDL-C ratio (LHR), and monocyte-to-HDL-C ratio (MHR) was evaluated using the area under the receiver operating characteristic curve (AUC). Restrictive cubic splines (RCS) were employed to explore the relationship between NHR and 12-month transplant-free (TF) mortality. This study included a prospective test cohort of 328 patients.

Results

NHR was identified as an independent risk factor for 12-month TF mortality. The AUC for NHR (0.776) was similar to that of the model end-stage liver disease (MELD) score (AUC: 0.777). In the test cohort, NHR demonstrated AUC values comparable to MELD, with significantly higher AUCs than LHR and MHR (both p < 0.05). Based on cutoff values for NHR and MELD, patients were classified into four risk subgroups: very-low (NHR < 10 and MELD <18), low (NHR ≥ 10 and MELD <18), moderate (NHR < 10 and MELD ≥18), and high (NHR ≥ 10 and MELD ≥18). The 12-month TF mortality rates in the training cohort were 7.2, 23.5, 30.8, and 51.4%, respectively, for these subgroups, while in the test cohort, the rates were 8.7, 20.5, 30.7, and 46.0%.

Conclusion

NHR is a valuable and accessible prognostic indicator for 12-month TF mortality in patients with HBV-related OHE. Patients with both NHR ≥ 10 and MELD ≥18 are at the highest risk of mortality.

Rapid determination of sphingosine 1-phosphate association with carrier molecules by flow-induced dispersion analysis to predict sepsis outcome

Flow-induced dispersion analysis (FIDA) was used to investigate the association of fluorescein isothiocyanate-labeled signaling lipid sphingosine 1-phosphate (S1P) with its carrier molecules human serum albumin (HSA) and high-density lipoprotein (HDL). Associations were measured in plasma samples of patients after surgery, with sepsis or septic shock. All patients demonstrated a significant shift between the carrier binding: decrease of S1P bound to HSA with a concomitant increase of S1P bound to HDL. The molecular sizes of binding complexes correlated well with the relative amounts of S1P bound to HSA and HDL detected by liquid chromatography-tandem mass spectrometry. Very low complex formation of S1P with HDL was observed in several septic shock patients and correlated with the need for mechanical ventilation and intensive care unit (ICU) mortality. Determination of S1P binding to HSA and HDL by FIDA could therefore be useful in the clinical setting to predict disease progression, severity, and outcome.