Plasma apolipoprotein M responses to statin and fibrate administration in type 2 diabetes mellitus

doi:10.1016/j.atherosclerosis.2010.07.048

Atherosclerosis

Volume 213, Issue 1, November 2010, Pages 247-250

https://doi.org/10.1016/j.atherosclerosis.2010.07.048 Get rights and content

Abstract

Purpose

Plasma apolipoprotein M (apoM) is potentially anti-atherogenic, and has been found to be associated positively with plasma total, LDL and HDL cholesterol in humans. ApoM may, therefore, be intricately related to cholesterol metabolism. Here, we determined whether plasma apoM is affected by statin or fibrate administration in patients with diabetes mellitus.

Methods

Fourteen type 2 diabetic patients participated in a placebo-controlled crossover study which included three 8-week treatment periods with simvastatin (40 mg daily), bezafibrate (400 mg daily), and their combination.

Results

ApoM was decreased by 7% in response to simvastatin (P < 0.05 from baseline and placebo), and remained unchanged during bezafibrate and combined simvastatin + bezafibrate administration. Plasma apoM concentrations correlated positively with apoB-containing lipoprotein measures at baseline and during placebo (P < 0.02 to P < 0.001), but these relationships were lost during all lipid lowering treatment periods.

Conclusions

This study suggests that, even though plasma apoM is lowered by statins, apoM metabolism is to a considerable extent independent of statin- and fibrate-affected pathways involved in cholesterol homeostasis.

Introduction

Apolipoprotein (apo) M is a recently identified apolipoprotein which is mainly expressed in liver and kidney [1], [2]. ApoM binds to lipoproteins via its retained signal peptide which serves as a lipophilic anchor [1]. ApoM is located mainly in the HDL fraction and to a minor extent in LDLs isolated from normolipidemic human plasma [3]. In human populations, plasma apoM levels are correlated positively with total cholesterol, LDL cholesterol and HDL cholesterol [4], [5], [6], [7], [8].

Interestingly, it has been shown that apoM retards atherosclerosis development in murine models [1], [9], [10]. Atheroprotective effects of apoM could possibly be attributed to the ability of this apolipoprotein to generate lipid poor pre-β particles which serve as early acceptors of cellular cholesterol in the anti-atherogenic reverse cholesterol transport pathway, as well as to its anti-oxidative properties [1], [3], [7].

Experimental evidence is accumulating that apoM regulation may be intricately related to LDL cholesterol homeostasis. ApoM overexpression and apoM deficiency increase and decrease plasma cholesterol, respectively [10]. Recently, an increasing effect of apoM on VLDL + LDL cholesterol was found to be dependent on an intact LDL receptor [11]. Moreover, plasma apoM is increased in murine models of LDL receptor deficiency [11]. These findings raise the possibility that plasma apoM levels may be decreased in response to administration of cholesterol lowering drugs. Nevertheless, the effects of pharmacological cholesterol lowering on human plasma apoM are still unexplored.

In this study we tested the extent to which statin and fibrate administration, alone and in combination, affect plasma apoM levels in type 2 diabetic patients.

Section snippets

Subjects

The medical ethics committee of the University Medical Center Groningen approved the study. Written informed consent was obtained from all the subjects. Non-smoking male patients, aged > 18 years, with previously diagnosed type 2 diabetes mellitus participated. Diabetes treatment consisted of diet alone or combined with oral glucose lowering agents. Patients using lipid lowering drugs, insulin, thiazolidinediones and/or anti-hypertensive medication were excluded. None of the subjects had a

Results

Fourteen type 2 diabetic patients (mean age 55 ± 8 years, diabetes duration 4 ± 2 years) participated. Their BMI, systolic blood pressure and diastolic blood pressure were 28.3 ± 4.7 kg/m², 127 ± 10 mm Hg and 80 ± 7 mm Hg, respectively. Two patients were treated with diet only, 6 patients used metformin and 3 patients used sulfonylurea derivates alone; 3 patients used both drugs. These medications were continued during the study. BMI and blood pressure were unchanged during the study (data not shown). Fasting

Discussion

This placebo-controlled study demonstrates that plasma apoM is decreased by simvastatin administration in type 2 diabetes. However, apoM remained unchanged during combined simvastatin and bezafibrate administration, contrasting expectedly large reductions in apoB-containing lipoproteins [12]. Our report thus shows that pharmacological lowering of apoB-containing lipoproteins does not decrease plasma apoM when obtained with an HDL-raising therapy.

We determined effects of statin and fibrate

Disclosure statement

The authors have nothing to disclose.

Acknowledgments

This study is in part supported by grant 2001.00.012 from the Dutch Diabetes Research Foundation, the Danish National Research Council (217-07-0352), the Novo Nordisk Foundation, and the Rigshospitalet, Copenhagen (to LBN), and the Swedish Research Council (#07143), the Swedish Heart-Lung Foundation, the A. Påhlsson Foundation and the Wallenberg Foundation (to BD). The analytical help of G. Visch, Isala Clinics, Zwolle, The Netherlands, is appreciated.

References (17)

L.B. Nielsen et al.
ApoM: gene regulation and effects on HDL metabolism
Trends Endocrinol Metab
(2009)
Y.W. Hu et al.
Characteristics of apolipoprotein M and its relation to atherosclerosis and diabetes
Biochim Biophys Acta
(2010)
O. Axler et al.
An ELISA for apolipoprotein M reveals a strong correlation to total cholesterol in human plasma
J Lipid Res
(2007)
J. Ahnstrom et al.
Levels of apolipoprotein M are not associated with the risk of coronary heart disease in two independent case–control studies
J Lipid Res
(2008)
R.P.F. Dullaart et al.
Plasma apolipoprotein M is reduced in metabolic syndrome but does not predict intima media thickness
Clin Chim Acta
(2009)
E.M. Ooi et al.
Association of apolipoprotein M with high-density lipoprotein kinetics in overweight-obese men
Atherosclerosis
(2010)
C. Christoffersen et al.
Effect of apolipoprotein M on high density lipoprotein metabolism and atherosclerosis in low density lipoprotein receptor knock-out mice
J Biol Chem
(2008)
S. Bilz et al.
Effects of atorvastatin versus fenofibrate on apoB-100 and apoA-I kinetics in mixed hyperlipidemia
J Lipid Res
(2004)

There are more references available in the full text version of this article.

Cited by (16)

Absolute quantification of apolipoproteins following treatment with omega-3 carboxylic acids and fenofibrate using a high precision stable isotope-labeled recombinant protein fragments based SRM assay
2019, Molecular and Cellular Proteomics
Citation Excerpt :
In this study, we found a negative correlation between changes in apoLI and changes in HDL-C in the placebo group, but weaker associations in the active treatment arms. In previous studies, fibrates either did not affect apoM levels (bezafibrate) (43) or increased apoM (fenofibrate) (36). In summary, a robust SIS PrEST-based SRM assay has been developed and shows high precision for apolipoprotein quantification.
Stable isotope-labeled standard (SIS) peptides are used as internal standards in targeted proteomics to provide robust protein quantification, which is required in clinical settings. However, SIS peptides are typically added post trypsin digestion and, as the digestion efficiency can vary significantly between peptides within a protein, the accuracy and precision of the assay may be compromised. These drawbacks can be remedied by a new class of internal standards introduced by the Human Protein Atlas project, which are based on SIS recombinant protein fragments called SIS PrESTs. SIS PrESTs are added initially to the sample and SIS peptides are released on trypsin digestion. The SIS PrEST technology is promising for absolute quantification of protein biomarkers but has not previously been evaluated in a clinical setting. An automated and scalable solid phase extraction workflow for desalting and enrichment of plasma digests was established enabling simultaneous preparation of up to 96 samples. Robust high-precision quantification of 13 apolipoproteins was achieved using a novel multiplex SIS PrEST-based LC-SRM/MS Tier 2 assay in non-depleted human plasma. The assay exhibited inter-day coefficients of variation between 1.5$ and 14.5$ (median = 3.5$) and was subsequently used to investigate the effects of omega-3 carboxylic acids (OM3-CA) and fenofibrate on these 13 apolipoproteins in human plasma samples from a randomized placebo-controlled trial, EFFECT I (NCT02354976). no significant changes were observed in the OM3-CA arm, whereas treatment with fenofibrate significantly increased apoAII and reduced apoB, apoCI, apoE and apoCIV levels. The reduction in apoCIV following fenofibrate treatment is a novel finding. The study demonstrates that SIS PrESTs can facilitate the generation of robust multiplexed biomarker Tier 2 assays for absolute quantification of proteins in clinical studies.
Apolipoprotein M in patients with chronic kidney disease
2018, Atherosclerosis
Citation Excerpt :
These profound changes of lipoprotein and lipid metabolism, especially the changes of HDL, may potentially contribute to the lower plasma APOM levels observed in CKD patients. The fact that cholesterol-lowering treatment reduced plasma APOM levels in patients with CKD was in agreement with previous findings in healthy subjects [36] and indicates that plasma APOM concentrations are very sensitive to changes of levels of LDL- and HDL-cholesterol. The paradoxical association of APOM with both the anti-atherogenic factor HDL-C and the pro-atherogenic factor LDL-C is in accordance with previous experimental findings [18,35].
Plasma apolipoprotein M (APOM) is bound to HDL-particles and has anti-atherogenic effects. The present study explored whether plasma APOM is reduced in patients with chronic kidney disease (CKD), and associated with cardiovascular disease (CVD). In addition, we tested the hypothesis that the excretion of APOM into the urine is increased in patients with kidney disease.
Plasma samples were collected from a cohort of patients with CKD stages 1 to 5D (N = 409) and controls (N = 35). Urine was collected from 47 subjects. Plasma APOM was measured with sandwich ELISA and urine APOM with competitive ELISA.
Plasma APOM levels were reduced in patients with CKD stages 3-5D as compared to patients with CKD stages 1 + 2 and controls (p < 0.01). CKD patients with known CVD displayed even further reduction in plasma APOM levels than CKD patients without known CVD (p < 0.001).
Fast-phase liquid chromatography showed that plasma APOM was primarily associated with HDL-cholesterol (HDL-C) across CKD stages. Accordingly, when plasma APOM values were corrected for HDL-C, a significant difference only persisted between patients with CKD stage 3 and stages 1 + 2 (p < 0.05), and the difference between CKD patients with and without known CVD disappeared. Urine APOM/creatinine ratio was not significantly increased in patients with kidney disease.
The results show that the difference in plasma APOM levels observed between patients with mild and advanced CKD may mainly be due to differences in plasma HDL-C.
Whether APOM plays a role in human uremic atherogenesis warrants further experimental studies.
LDL receptor and ApoE are involved in the clearance of ApoM-associated sphingosine 1-phosphate
2015, Journal of Biological Chemistry
Citation Excerpt :
The main function of the LDL receptor is the uptake of LDL from the circulation into the liver; therefore, it seems reasonable that the plasma S1P level should be positively related to the LDL cholesterol level. Actually, the treatment of HepG2 cells with an HMG-CoA reductase inhibitor, statin, accelerated the clearance of C17S1P bound to apoM-containing lipoproteins (Fig. 5), which is consistent with the results from a previous study demonstrating that statin treatment decreased the apoM level in human subjects (34). This result may suggest a limitation of the clinical benefit of statin: namely, the problem of residual risk.
Sphingosine 1-phosphate (S1P) is a vasoactive lipid mediator that is speculated to be involved in various aspects of atherosclerosis. About 70% of circulating plasma S1P is carried on HDL, and several pleiotropic properties of HDL have been ascribed to S1P. In the previous study with human subjects, however, LDL cholesterol or apoB, but not HDL cholesterol or apoA-I, had a significant positive correlation with the plasma S1P level, suggesting that the metabolic pathway for LDL might have some roles in the metabolism of S1P. In this study, we analyzed the association between LDL receptor, an important protein in the clearance of LDL, and circulating S1P. We observed that in LDL receptor-overexpressing mice, the plasma S1P levels as well as apolipoprotein M (apoM), a carrier of S1P, were decreased and that exogenously administered C₁₇S1P bound to apoM-containing lipoproteins was cleared more rapidly. Unlike the situation in wild-type mice, LDL receptor overexpression in apoE-deficient mice did not reduce the plasma S1P or apoM levels, suggesting that apoE might be a ligand for the LDL receptor during the clearance of these factors. The present findings clarify the novel roles of the LDL receptor and apoE in the clearance of S1P, a multifunctional bioactive phospholipid.A positive correlation exists between sphingosine 1-phosphate (S1P) and LDL cholesterol.
Hepatic LDL receptor overexpression decreased plasma S1P together with apoM in wild-type mice, but not in apoE-deficient mice.
LDL receptor is involved in the clearance of S1P, utilizing apoE as a ligand.
We propose the novel role of LDL receptor and apoE in the clearance of S1P.
The plasma concentration of HDL-associated apoM is influenced by LDL receptor-mediated clearance of apoB-containing particles
2012, Journal of Lipid Research
Citation Excerpt :
As such, the data provide a likely explanation for the positive association between plasma LDL cholesterol and plasma apoM in humans. Furthermore, the results are compatible with recent findings that use of statins lowers plasma apoM (29) and that plasma apoM concentrations are positively associated with plasma levels of the LDL receptor-degrading protease proprotein convertase subtilisin/kexin type 9 (30) in humans. Hence, the available data suggest a so-far-unknown link between LDL receptor-mediated clearance of apoB-containing lipoproteins and the metabolism of a mainly HDL-associated apolipoprotein.
ApoM is mainly associated with HDL. Nevertheless, we have consistently observed positive correlations of apoM with plasma LDL cholesterol in humans. Moreover, LDL receptor deficiency is associated with increased plasma apoM in mice. Here, we tested the idea that plasma apoM concentrations are affected by the rate of LDL receptor-mediated clearance of apoB-containing particles. We measured apoM in humans each carrying one of three different LDL receptor mutations (n = 9) or the apoB3500 mutation (n = 12). These carriers had increased plasma apoM (1.34 ± 0.13 µM, P = 0.003, and 1.23 ± 0.10 µM, P = 0.02, respectively) as compared with noncarriers (0.93 ± 0.04 µM). When we injected human apoM-containing HDL into Wt (n = 6) or LDL receptor-deficient mice (n = 6), the removal of HDL-associated human apoM was delayed in the LDL receptor-deficient mice. After 2 h, 54 ± 5% versus 90 ± 8% (P < 0.005) of the initial amounts of human apoM remained in the plasma of Wt and LDL receptor-deficient mice, respectively. Finally, we compared the turnover of radio-iodinated LDL and plasma apoM concentrations in 45 normocholesterolemic humans. There was a negative correlation between plasma apoM and the fractional catabolic rate of LDL (r =−0.38, P = 0.009). These data suggest that the plasma clearance of apoM, despite apoM primarily being associated with HDL, is influenced by LDL receptor-mediated clearance of apoB-containing particles.
Relationship of plasma apolipoprotein M with proprotein convertase subtilisin-kexin type 9 levels in non-diabetic subjects
2011, Atherosclerosis
Apolipoprotein M (apoM) retards atherosclerosis development in murine models, and may be regulated by pathways involved in LDL metabolism. Proprotein convertase subtilisin–kexin type 9 (PCSK9) plays a key role in LDL receptor processing. We determined the extent to which plasma apoM is related to PCSK9 levels in subjects with varying degrees of obesity.
We sought correlations between plasma apoM and PCSK9, measured using recently developed ELISAs, in 79 non-diabetic subjects.
ApoM and PCSK9 levels were both correlated positively with total cholesterol, non-HDL cholesterol, LDL cholesterol and apoB (P < 0.05 to P < 0.001). ApoM correlated positively with PCSK9 in lean individuals (n = 37, r = 0.337, P = 0.041), but not in overweight subjects (n = 32, r = 0.125, P = 0.50) and in obese subjects (n = 10, r = −0.055, P = 0.88).
The PCSK9 pathway may contribute to plasma apoM regulation in humans. The influence of PCSK9 on circulating apoM appears to be modified by adiposity.
Identification of circulating apolipoprotein M as a new determinant of insulin sensitivity and relationship with adiponectin
2024, International Journal of Obesity

View all citing articles on Scopus

¹: These two authors contributed equally to this manuscript.

View full text

Short communicationPlasma apolipoprotein M responses to statin and fibrate administration in type 2 diabetes mellitus

Abstract

Purpose

Methods

Results

Conclusions

Introduction

Section snippets

Subjects

Results

Discussion

Disclosure statement

Acknowledgments

Trends Endocrinol Metab

Biochim Biophys Acta

J Lipid Res

J Lipid Res

Clin Chim Acta

Atherosclerosis

J Biol Chem

J Lipid Res

Short communication
Plasma apolipoprotein M responses to statin and fibrate administration in type 2 diabetes mellitus