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Low plasma concentrations of apolipoprotein M are associated with disease activity and endothelial dysfunction in
Helena Tydén1, Christian Lood2, Andreas Jönsen2
1Department of Rheumatology, Clinical Sciences, Lund University, SE-22185, Lund, Sweden. helena.tyden@med.lu.se.
Background:
Apolipoprotein M (apoM) is a 25-kDa apolipoprotein present in 5% of high-density lipoprotein (HDL) particles. It is suggested to be anti-atherogenic and to play a key role in sustaining endothelial barrier integrity. SLE patients have increased cardiovascular disease risk, and we aimed to investigate if apoM levels reflect endothelial function in SLE. Since apoM plasma levels decrease during inflammatory conditions, our aim was also to determine the impact of SLE disease activity on apoM plasma levels.
Methods:
Plasma concentrations of apoM were measured by ELISA in two patient groups with systemic lupus erythematosus (SLE) and in 79 healthy control individuals. In patient group I (n = 84), evaluation time points were selected with the objective to include a wide range of clinical and laboratory variables reflecting disease activity which was measured as SLEDAI. In patient group II consisting of 140 consecutive patients, endothelial function was measured by a finger plethysmograph. A low Reactive Hyperemia Index (RHI) value indicates endothelial dysfunction.
Results:
SLE patients had decreased levels of apoM compared to healthy controls (p < 0.01), with apoM levels correlating inversely with SLEDAI (r = - 0.31, p < 0.01) as well as with levels of CRP (r = - 0.26, p = 0.02) and positively with levels of C3 (r = 0.29, p < 0.01). ApoM levels were particularly low in patients with active disease from the kidney and skin and in patients with leukopenia or positive anti-dsDNA antibody test (p < 0.05). ApoM levels correlated with RHI values in young SLE patients (r = 0.32, p = 0.01), consistent with the important role of apoM in regulating endothelial integrity.
Conclusions:
ApoM levels may be regulated by SLE-related inflammatory processes and could be a marker of disease activity and endothelial dysfunction, in particular in young SLE patients. Further studies are needed to investigate the predictive value of apoM in the development of a cardiovascular disease.
Insights
Apolipoprotein M (apoM) levels are lower in systemic lupus erythematosus (SLE) patients and correlate with disease activity and endothelial dysfunction. These findings suggest apoM may serve as a biomarker for SLE disease severity and cardiovascular risk.
Area of Science:
- Cardiovascular Research
- Immunology
- Biochemistry
Background:
- Apolipoprotein M (apoM) is an apolipoprotein found in high-density lipoprotein (HDL) particles, implicated in anti-atherogenic effects and endothelial barrier integrity.
- Systemic lupus erythematosus (SLE) is associated with an increased risk of cardiovascular disease.
- The role of apoM in SLE and its relationship with endothelial function and disease activity require investigation.
Purpose of the Study:
- To investigate whether apoM plasma levels reflect endothelial function in patients with SLE.
- To determine the impact of SLE disease activity on apoM plasma levels, considering that apoM levels may decrease during inflammation.
Main Methods:
- Plasma apoM concentrations were measured using ELISA in two SLE patient cohorts and healthy controls.
- Disease activity was assessed using the SLE Disease Activity Index (SLEDAI).
- Endothelial function was evaluated using finger plethysmography to determine the Reactive Hyperemia Index (RHI).
Main Results:
- SLE patients exhibited significantly lower apoM levels compared to healthy controls (p < 0.01).
- ApoM levels showed an inverse correlation with SLEDAI (r = -0.31, p < 0.01) and C-reactive protein (CRP) (r = -0.26, p = 0.02), and a positive correlation with C3 levels (r = 0.29, p < 0.01).
- ApoM levels correlated with RHI in young SLE patients (r = 0.32, p = 0.01), indicating a link with endothelial integrity.
Conclusions:
- ApoM plasma levels may be influenced by SLE-related inflammatory processes.
- ApoM could serve as a potential biomarker for SLE disease activity and endothelial dysfunction, particularly in younger patients.
- Further research is warranted to explore the predictive value of apoM in the development of cardiovascular disease in SLE patients.
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