Effect of different lipid apheresis methods on plasma polyunsaturated fatty acids

Changing from lipoprotein apheresis to evolocumab treatment lowers circulating levels of arachidonic acid and oxylipins

Background and aims

Previous studies have shown that lipoprotein apheresis can modify the plasma lipidome and pro-inflammatory and pro-thrombotic lipid mediators. This has not been examined for treatment with protein convertase subtilisin/kexin type 9 inhibitors such as evolocumab, which are increasingly used instead of lipoprotein apheresis in treatment-resistant familial hypercholesterolemia. The aim of this study was to compare the effects of evolocumab treatment and lipoprotein apheresis on the fatty acid profile and on formation of lipid mediators in blood samples.

Methods

We analyzed blood samples from 37 patients receiving either lipoprotein apheresis or evolocumab treatment as part of a previous study. Patients were stratified according to receiving lipoprotein apheresis (n = 19) and evolocumab treatment (n = 18). Serum fatty acid analysis was performed using gas chromatography flame ionization detection and plasma oxylipin analysis was done using liquid chromatography tandem mass spectrometry.

Results

Changing from lipoprotein apheresis to evolocumab treatment led to lower levels of omega-6 polyunsaturated fatty acid (n-6 PUFA) including arachidonic acid, dihomo-γ-linolenic acid and linoleic acid. Moreover, several n-6 PUFA-derived oxylipins were reduced after evolocumab treatment.

Conclusions

Given that arachidonic acid, either directly or as a precursor, is associated with the development of inflammation and atherosclerosis, evolocumab-mediated reductions of arachidonic acid and its metabolites might have an additional beneficial effect to lower cardiovascular risk.

Fatty acid analysis in serum of patients with elevated lipoprotein(a) and cardiovascular disease undergoing lipoprotein apheresis

BACKGROUND

Lipoprotein apheresis (LA) is an extracorporeal treatment that transiently reduces lipoprotein (a) [Lp(a)] by 60% and leads to an 80-92% reduction in major adverse cardiovascular events. LA has a significant impact on lipid profile in serum of patients with atherosclerotic cardiovascular disease.

OBJECTIVE

To investigate the effects of LA on the composition of serum fatty acids (FAs), focusing on those which could have an impact on cardiovascular disease (CVD).

METHODS

This is a prospective study in the First Department of Cardiology of the Medical University of Gdansk, Poland. Serum samples were collected from 28 patients before LA, just after the procedure, and 7 days after LA. Additionally, in a smaller group of patients, the samples were collected after a second tour of LA (2 weeks later), as well as after 1 year from the first procedure. The serum FA profile was analyzed using gas chromatography-mass spectrometry.

RESULTS

After the LA procedure, a substantial change in serum FA composition along with low-density lipoprotein cholesterol (LDL-C) and Lp(a) decrease were observed 7 days after procedure, but these parameters returned to the values similar to those before procedure after 14 days. Very long-chain FAs (VLCFAs) and very long-chain monounsaturated FAs (VLC-MUFAs) were eluted at 57% and remained low even 7 days after LA (p=0.027 and p < 0.001, respectively). We also observed an increase in the percentage of total branched-chain FAs (BCFAs) (p=0.004) and anteiso BCFAs (p=0.012) after LA. After 1 year of regular LA, a substantial decrease in serum VLC-MUFAs and n3 polyunsaturated LA (PUFAs) were noted.

CONCLUSIONS

Decreased VLCFAs and VLC-MUFAs involved in CVD development remained low even 7 days after LA. An acute increase in the levels of anti-inflammatory BCFAs was observed. In turn long-term regular administration of LA substantially decreased VLC-MUFA and n3 PUFA.

Essential Polyunsaturated Fatty Acids in Blood from Patients with and without Catheter-Proven Coronary Artery Disease

Coronary artery disease (CAD) is the leading cause of death worldwide. Statins reduce morbidity and mortality of CAD. Intake of n-3 polyunsaturated fatty acid (n-3 PUFAs), particularly eicosapentaenoic acid (EPA), is associated with reduced morbidity and mortality in patients with CAD. Previous data indicate that a higher conversion of precursor fatty acids (FAs) to arachidonic acid (AA) is associated with increased CAD prevalence. Our study explored the FA composition in blood to assess n-3 PUFA levels from patients with and without CAD. We analyzed blood samples from 273 patients undergoing cardiac catheterization. Patients were stratified according to clinically relevant CAD (n = 192) and those without (n = 81). FA analysis in full blood was performed by gas chromatography. Indicating increased formation of AA from precursors, the ratio of dihomo-gamma-linolenic acid (DGLA) to AA, the delta-5 desaturase index (D5D index) was higher in CAD patients. CAD patients had significantly lower levels of omega-6 polyunsaturated FAs (n-6 PUFA) and n-3 PUFA, particularly EPA, in the blood. Thus, our study supports a role of increased EPA levels for cardioprotection.

Lipoprotein apheresis efficacy and challenges: single center experience

Introduction

Lipoprotein apheresis (LA) is an extracorporeal therapy which removes apolipoprotein B-containing particles from the circulation. We evaluated techniques and efficiency of lipoprotein apheresis procedures applied to patients with familial and non-familial hypercholesterolemia (FH) at our center.

Methods

We retrospectively evaluated 250 LA procedures applied to 27 patients with dyslipidemia between March 2011 and August 2019.

Results

A total of 27 patients, of whom 19 (70.4%) were male and 8 (29.6%), female, were included. Eighteen (66.7%), 6 (22.2%) and 3 (11.1%) patients were diagnosed with non-FH, homozygous FH (HoFH) and heterozygous FH (HeFH), respectively. Two different apheresis techniques, direct adsorption of lipoproteins (DALI) (48.8%) and double filtration plasmapheresis (DFPP) (51.2%), were used. The change in the serum total cholesterol (TC) level was the median 302 mg/dl (171–604 mg/dl) (60.4%) in HoFH patients, 305 mg/dl (194–393 mg/dl) (60.8%) in HeFH patients and 227 mg/dl (75–749 mg/dl) (65.3%) in non-FH patients. The change in the serum low-density lipoprotein (LDL) level was the median 275 mg/dl (109–519 mg/dl) (64.2%), 232 mg/dl (207–291 mg/dl) (64.5%) and 325 mg/dl (22–735 mg/dl) (70.9%) in patients with HoFH, HeFH and non-FH, respectively. A significantly effective reduction in serum lipid levels, including TC, LDL and triglycerides, was achieved in all patients, regardless of the technique, p < .001. The decrease in the serum TC and LDL levels was significantly higher in the DFPP, compared to the DALI, being 220 mg/dl (−300 to 771) vs 184 mg/dl (64–415), p < .001 and 196 mg/dl (11–712) vs 157 mg/dl (54–340), p < .001, respectively.

Conclusions

Our results showed that LA is a highly effective treatment in reducing serum lipid levels and safe, without any major adverse event.

Lipoprotein(a) concentration is associated with plasma arachidonic acid in subjects with familial hypercholesterolaemia

Elevated lipoprotein(a) (Lp(a)) is associated with CVD and is mainly genetically determined. Studies suggest a role of dietary fatty acids (FA) in the regulation of Lp(a); however, no studies have investigated the association between plasma Lp(a) concentration and n-6 FA. We aimed to investigate whether plasma Lp(a) concentration was associated with dietary n-6 FA intake and plasma levels of arachidonic acid (AA) in subjects with familial hypercholesterolaemia (FH). We included FH subjects with (n 68) and without (n 77) elevated Lp(a) defined as ≥75 nmol/l and healthy subjects (n 14). Total FA profile was analysed by GC-flame ionisation detector analysis, and the daily intake of macronutrients (including the sum of n-6 FA: 18 : 2n-6, 20 : 2n-6, 20 : 3n-6 and 20 : 4n-6) were computed from completed FFQ. FH subjects with elevated Lp(a) had higher plasma levels of AA compared with FH subjects without elevated Lp(a) (P = 0·03). Furthermore, both FH subjects with and without elevated Lp(a) had higher plasma levels of AA compared with controls (P < 0·001). The multivariable analyses showed associations between dietary n-6 FA intake and plasma levels of AA (P = 0·02) and between plasma levels of Lp(a) and AA (P = 0·006). Our data suggest a novel link between plasma Lp(a) concentration, dietary n-6 FA and plasma AA concentration, which may explain the small diet-induced increase in Lp(a) levels associated with lifestyle changes. Although the increase may not be clinically relevant, this association may be mechanistically interesting in understanding more of the role and regulation of Lp(a).

Activation of Lipid Mediator Formation Due to Lipoprotein Apheresis

Lipoprotein apheresis reliably reduces low-density lipoprotein (LDL) cholesterol in patients with atherosclerotic disease and therapy-refractory hypercholesterolemia or elevated lipoprotein (a) (Lp(a)). Besides lowering lipoproteins and triglycerides, apheresis also decreases levels of essential omega-6 and omega-3 polyunsaturated fatty acids (n-6 and n-3 PUFAs) in blood plasma. In contrast, heparin-induced extracorporeal low-density lipoprotein precipitation (HELP) lipid apheresis might increase the formation of potentially pro-inflammatory and pro-thrombotic lipid mediators derived from n-6 and n-3 PUFAs. The study presented here analyzed lipid mediator profiles in the plasma of patients with hyperlipidemia treated by one of three different apheresis methods, either HELP, direct absorption (DA), or membrane filtration (MDF), in a direct pre- and post-apheresis comparison. Using gas chromatography and liquid chromatography tandem mass spectrometry (LC-MS/MS) we were able to analyze fatty acid composition and the formation of lipid mediators called oxylipins. Our data illustrate—particularly in HELP-treated patients—significant decreases of essential omega-6 and omega-3 polyunsaturated fatty acids in blood plasma but significant increases of PUFA-derived lipoxygenase-, as well as cyclooxygenase- and cytochrome P450-derived lipid mediators. Given that n-3 PUFAs in particular are presumed to be cardioprotective and n-3 PUFA-derived lipid mediators might limit inflammatory reactions, these data indicate that n-3 PUFA supplementation in the context of lipid apheresis treatment might have additional benefits through apheresis-triggered protective n-3 PUFA-derived lipid mediators.