A placebo-controlled proof-of-concept study of alirocumab on postprandial lipids and vascular elasticity in insulin-treated patients with type 2 diabetes mellitus

Effect of alirocumab on postprandial hyperlipidaemia in patients with type 2 diabetes: A randomized, double-blind, placebo-controlled, cross-over trial

AIMS

Postprandial hyperlipidaemia (PPL), characterized by elevated triglyceride (TG) concentrations after a meal, is common in type 2 diabetes (T2D) and is often recognized as an independent cardiovascular risk factor. Here, we aimed to assess the effect of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition by alirocumab on PPL in patients with T2D.

MATERIALS AND METHODS

EUTERPE is a randomized, double-blind, placebo-controlled cross-over trial conducted in male patients with T2D. Participants received sequentially two sequences of 10-week treatment (alirocumab 75 mg Q2W or placebo s/c) with a wash-out period of 10 weeks. The primary end-point was the percentage reduction in plasma TG response after an oral fat load (incremental area under the curve [iAUC]0-8h TG). Secondary end-points included mass spectrometry-based apolipoprotein measurements and nuclear magnetic resonance (NMR)-based lipoprotein profiling.

RESULTS

Fourteen participants were included: age 59 ± 9 years, BMI 32.8 ± 5.5 kg/m2, HbA1C 6.7 ± 0.5%. Compared to placebo, alirocumab did not reduce PPL (iAUC0-8h TG: -5% [CI 95%: -28, +25], p = 0.68). Alirocumab decreased fasting non-HDL cholesterol (-38.5 ± 5.6%, p = 0.0003), remnant cholesterol (-20.0 ± 13.3%, p = 0.04), apoB100 (-21.2 ± 6.4%, p = 0.004) and apoE (-15.3 ± 6.6%, p = 0.02) concentrations. NMR analyses showed that alirocumab decreased both postprandial VLDL2 cholesterol (-42% [-55, -25], p < 0.001) and IDL cholesterol (-26% [-38, -12], p = 0.0007), without effect on VLDL1 cholesterol or TG concentrations.

CONCLUSIONS

Inhibition of PCSK9 by alirocumab did not reduce PPL in T2D, confirming that PCSK9 controls remnant cholesterol catabolism rather than intestinal chylomicron production.

Efficacy and safety of PCSK9 inhibitors in patients with diabetes: A systematic review and meta-analysis

AIMS

Individuals with diabetes have increased cardiovascular risk. Although PCSK9 inhibitors bring about a wide reduction in lipids, there is uncertainty about the effects for diabetic patients. We conducted a systematic review and meta-analysis to assess the efficacy and safety of PCSK9 inhibitors for diabetes.

DATA SYNTHESIS

We performed a meta-analysis comparing treatment with PCSK9 inhibitors versus controls up to July 2022. Primary efficacy endpoints were percentage changes in lipid profile parameters. We used random effects meta-analyses to combine data. Subgroups of diabetic patients (by diabetes type, baseline LDL-C, baseline HbA1c and follow-up time) were also compared. We included 12 RCTs comprising 14,702 patients. Mean reductions in LDL-C were 48.20% (95% CI: 35.23%, 61.17%) in patients with diabetes. Reductions observed with PCSK9 inhibitors were 45.23% (95% CI: 39.43%, 51.02%) for non-HDL-cholesterol, 30.39% (95% CI: 24.61%, 36.17%) for total cholesterol, 11.96% (95% CI: 6.73%, 17.19%) for triglycerides, 27.87% (95% CI: 22.500%, 33.17%) for lipoprotein(a), 42.43% (95% CI: 36.81%, 48.06%) for apolipoprotein B; increases in HDL-C of 5.97% (95% CI: 4.59%, 7.35%) were also observed. There was no significant difference in fasting plasma glucose (FPG) (WMD: 2.02 mg/mL; 95% CI: -1.83, 5.87) and HbA1c (WMD: 1.82%; 95% CI: -0.63, 4.27). Use of a PCSK9 inhibitor was not associated with increased risk of treatment-emergent adverse event (TEAE) (p = 0.542), serious adverse event (SAE) (p = 0.529) and discontinuations due to AEs (p = 0.897).

CONCLUSIONS

PCSK9 inhibitor therapy should be considered for all diabetic individuals at high risk of atherosclerotic cardiovascular disease.

REGISTRATION CODE IN PROSPERO

CRD42022339785.

Effect of evolocumab on fasting and post fat load lipids and lipoproteins in familial dysbetalipoproteinemia

BACKGROUND

Familial dysbetalipoproteinemia (FD) is the second most common monogenic lipid disorder (prevalence 1 in 850-3500), characterized by postprandial remnant accumulation and associated with increased cardiovascular disease (CVD) risk. Many FD patients do not achieve non-HDL-C treatment goals, indicating the need for additional lipid-lowering treatment options.

OBJECTIVES

To evaluate the effect of the PCSK9 monoclonal antibody evolocumab added to standard lipid-lowering therapy on fasting and post fat load lipids and lipoproteins in patients with FD.

METHODS

A randomized placebo-controlled double-blind crossover trial comparing evolocumab (140 mg subcutaneous every 2 weeks) with placebo during two 12-week treatment periods. At the start and end of each treatment period patients received an oral fat load. The primary endpoint was the 8-hour post fat load non-HDL-C area under the curve (AUC). Secondary endpoints included fasting and post fat load lipids and lipoproteins.

RESULTS

In total, 28 patients completed the study. Mean age was 62±9 years and 93% had an Ɛ2Ɛ2 genotype. Evolocumab reduced the 8-hour post fat load non-HDL-C AUC with 49% (95%CI 42-55) and apolipoprotein B (apoB) AUC with 47% (95%CI 41-53). Other fasting and absolute post fat load lipids and lipoproteins including triglycerides and remnant-cholesterol were also significantly reduced by evolocumab. However, evolocumab did not have significant effects on the rise above fasting levels that occurred after consumption of the oral fat load.

CONCLUSIONS

Evolocumab added to standard lipid-lowering therapy significantly reduced fasting and absolute post fat load concentrations of non-HDL-C, apoB and other atherogenic lipids and lipoproteins in FD patients. The clinically significant decrease in lipids and lipoproteins can be expected to translate into a reduction in CVD risk in these high-risk patients.

PCSK9 inhibitors for anti-inflammation in atherosclerosis: protocol for a systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

Atherosclerosis is the leading cause of cardiovascular disease (CVD), which is one of the most common causes of morbidity and mortality worldwide. Lipid accumulation and inflammation play a crucial role in the pathogenesis of atherosclerosis. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are an emerging lipid-lowering agent reported as a potential anti-inflammation effect in the prevention of CVD. However, the anti-inflammatory effect is still elusive. Therefore, a systematic review and meta-analysis is needed to analyse the anti-inflammatory effect of PCSK9 inhibitors on atherosclerosis in practice.

METHODS AND ANALYSIS

This protocol was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols. We will include double-blind, randomised controlled trials that reported changes in the levels of inflammatory markers, with an intervention arm of PCSK9 inhibitors and a treatment duration of more than 2 weeks. The following databases will be mainly searched from 1 January 2003 to the formal search date: PubMed, Embase, Web of Science and the Cochrane Central Register of Controlled Trials. The primary aim is to assess the effect of PCSK9 inhibitors on inflammatory markers, including circulating inflammatory markers such as C-reactive protein, high-sensitivity C-reactive protein, white cell counts, IL-1β, IL-6 and TNF-α and local inflammatory markers such as the most diseased segment target-to-background ratio of the index vessel in adult patients with atherosclerosis. We will assess the quality of evidence, heterogeneity and report bias following the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions.

ETHICS AND DISSEMINATION

Due to the systematic review being based on published studies, no ethics approval is required. The study results will be presented at international conferences and published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022297710.

PCSK9 Plasma Levels Are Associated with Mechanical Vascular Impairment in Familial Hypercholesterolemia Subjects without a History of Atherosclerotic Cardiovascular Disease: Results of Six-Month Add-On PCSK9 Inhibitor Therapy

Proprotein convertase subtilisin/kexin type-9 (PCSK9) is a key regulator of low-density lipoprotein (LDL) metabolism involved in the degradation of the low-density lipoprotein receptor (LDLR) through complex mechanisms. The PCSK9 plasma levels change according to lipid lowering therapy (LLT). Few data exist regarding the role of PCSK9 in vascular damage. We aimed to evaluate the impact of PCSK9 plasma levels on pulse wave velocity (PWV) and the effect of PCSK9 inhibitors (PCSK9-i) on circulating PCSK9 and PWV in a cohort of heterozygous familial hypercholesterolemia (HeFH) subjects. In a previous step, HeFH patients were enrolled and LLT was prescribed according to guidelines. Biochemical analyses and PWV assessment were performed at baseline (T0), after 6 months of high-efficacy statin plus ezetimibe (T1) and after 6 months of PCSK9-i (T2). The PCSK9 levels were evaluated in 26 selected HeFH subjects at the three time points and 26 healthy subjects served as controls for the reference value for PCSK9 plasma levels. The PWV values decreased at each time point in HeFH subjects after LLT starting (8.61 ± 2.4 m/s, −8.7%; p < 0.001 vs. baseline at T1, and 7.9 ± 2.1 m/s, −9.3%; p < 0.001 vs. both T1 and baseline) and it was correlated to PCSK9 (r = 0.411, p = 0.03). The PCSK9 levels increased on statin/EZE therapy (+42.8% at T1) while it decreased after PCSK9-i was started (−34.4% at T2). We noted a significant relationship between PCSK9 levels and PWV changes at T1 and T2. In conclusion, PCSK9 levels were associated with baseline PWV values in HeFH subjects; moreover, we found that PCSK9 level variations seemed to be correlated with PWV changes on LLT. A longer observation time and wider sample size are needed to assess the potential role of PCSK9 plasma levels on the vascular function and remodelling, and to clarify the effects of PCSK9-i in these pathways.

Effects of Alirocumab on Triglyceride Metabolism: A Fat-Tolerance Test and Nuclear Magnetic Resonance Spectroscopy Study

Background: PCSK9 antibodies strongly reduce LDL cholesterol. The effects of PCSK9 antibodies on triglyceride metabolism are less pronounced. The present study aimed to investigate in detail the effects of alirocumab on triglycerides, triglyceride-rich lipoproteins, and lipase regulators. Methods: A total of 24 patients with an indication for treatment with PCSK9 antibodies were recruited. There were two visits at the study site: the first before initiation of treatment with alirocumab and the second after 10 weeks of treatment. Fat-tolerance tests, nuclear magnetic resonance spectroscopy, and enzyme-linked immunosorbent assays were performed to analyze lipid metabolism. Results: A total of 21 participants underwent the first and second investigation. Among these, two participants only received alirocumab twice and 19 patients completed the trial per protocol. All of them had atherosclerotic vascular disease. There was no significant effect of alirocumab treatment on fasting triglycerides, post-prandial triglycerides, or lipoprotein-lipase regulating proteins. Total, large, and small LDL particle concentrations decreased, while the HDL particle concentration increased (all p < 0.001). Mean total circulating PCSK9 markedly increased in response to alirocumab treatment (p < 0.001). Whereas PCSK9 increased more than three-fold in all 19 compliant patients, it remained unchanged in those two patients with two injections only. Conclusion: Significant effects of alirocumab on triglyceride metabolism were not detectable in the ALIROCKS trial. The total circulating PCSK9 concentration might be a useful biomarker to differentiate non-adherence from non-response to PCSK9 antibodies.

Postprandial Lipid Metabolism in Normolipidemic Subjects and Patients with Mild to Moderate Hypertriglyceridemia: Effects of Test Meals Containing Saturated Fatty Acids, Mono-Unsaturated Fatty Acids, or Medium-Chain Fatty Acids

Fasting and postprandial hypertriglyceridemia are causal risk factors for atherosclerosis. The prevalence of hypertriglyceridemia is approximately 25–30% and most hypertriglyceridemic patients suffer from mild to moderate hypertriglyceridemia. Data regarding dietary interventions on postprandial triglyceride metabolism of mildly to moderately hypertriglyceridemic patients is, however, sparse. In a randomized controlled trial, eight mildly hypertriglyceridemic patients and five healthy, normolipidemic controls received three separate standardized fat-meals containing either saturated fatty acids (SFA), mono-unsaturated fatty acids (MUFA), or medium-chain fatty acids (MCFA) in a randomized order. Fasting and postprandial lipid parameters were determined over a 10 h period and the (incremental) area under the curve (AUC/iAUC) for plasma triglycerides and other parameters were determined. MCFA do not lead to a significant elevation of postprandial total plasma triglycerides and other triglyceride parameters, while both SFA (patients: p = 0.003, controls: p = 0.03 compared to MCFA) and MUFA (patients: p = 0.001; controls: p = 0.14 compared to MCFA) do lead to such an increase. Patients experienced a significantly more pronounced increase of plasma triglycerides than controls (SFA: patients iAUC = 1006 mg*h/dL, controls iAUC = 247 mg*h/dL, p = 0.02; MUFA: patients iAUC = 962 mg*h/dL, controls iAUC = 248 mg*h/dL, p = 0.05). Replacing SFA with MCFA may be a treatment option for mildly to moderately hypertriglyceridemic patients as it prevents postprandial hypertriglyceridemia.

Cholesterol lowering therapies and achievement of targets for primary and secondary cardiovascular prevention in type 2 diabetes: unmet needs in a large population of outpatients at specialist clinics

BACKGROUND

The well-established benefit of Low-Dense-Lipoprotein-cholesterol (LDL-c) lowering treatments (LLTs) has led clinical guidelines to lower the cardiovascular prevention targets. Despite this, there is a surprising scarcity of real-world studies (RWS) evaluating whether recommendations are applied in the routine clinical management of patients with type 2 diabetes (T2D). We therefore evaluated, in a large RWS, the pattern of LLTs use and the achievement of LDL-c targets in patients with T2D in Italian diabetes specialist clinics.

METHODS

We collected data from 46 diabetes outpatient clinics (following 281,381 subjects), including 104,726 T2D patients, for whom use of LLTs between 2015 and 2016 was ascertained. We used the 2016 and 2019 European Atherosclerosis Society and European Society of Cardiology (EAS-ESC) guidelines to define cardiovascular risk categories, LDL-c targets, and the expected LDL-c reduction and cardiovascular benefit achievable with LLT intensification.

RESULTS

63,861 patients (61.0%) were on statin therapy, 9.2% of whom were also on ezetimibe. Almost all subjects were at high (29.3%) or very high (70.4%) cardiovascular risk, including 17% being in secondary prevention. Among very high-risk patients, 35% were not on statin despite half of them had LDL-c > 2.6 mmol/l, and only 15% of those on statins had LDL-c < 1.4 mmol/l. 83% of subjects in secondary prevention were on a statin, but half of them had LDL-c > 1.8 mmol/l. Overall, 35% and 14% of subjects achieved the LDL-c targets as suggested by 2016 and 2019 EAS-ESC Guidelines, respectively. Based on anticipated response to treatment, we estimated that 38% of the entire population would require high-intensity-statin (HI-statin), 27% a combination of HI-statin plus ezetimibe, and 27% the addition of proprotein-convertase-subtilisin/kexin-9 (PCSK9) inhibitors. These LLT intensifications would reduce the incidence of cardiovascular events by 32%, from 23.511 to 16.022 events per 100.000 patients/10-years (incidence-rate-ratio 0.68; 95% C.I 0.67-0.70, p < 0.001).

CONCLUSIONS

Despite the increase in use of LLT in T2D over the last decades, a large proportion of subjects with T2D did not achieve their LDL-c targets. Given the very high cardiovascular risk of these patients, improving LLT is expected to have a dramatic impact on cardiovascular event prevention.

Efficacy and safety of icosapent ethyl in hypertriglyceridaemia: a recap

Although low-density lipoprotein cholesterol lowering is effective in atherosclerotic cardiovascular disease (ASCVD) prevention, considerable ‘lipid-associated’ residual risk remains, particularly in patients with mild-to-moderate hypertriglyceridaemia (2–10 mmol/L; 176–880 mg/dL). Triglyceride (TG)-rich lipoproteins carry both TGs and cholesterol (remnant-cholesterol). At TG levels >5 mmol/L (440 mg/dL) vs. <1 mmol/L (88 mg/dL) or remnant-cholesterol >2.3 mmol/L (89 mg/dL) vs. <0.5 mmol/L (19 mg/dL), risk is ∼1.5-fold elevated for aortic stenosis, 2-fold for all-cause mortality, 3-fold for ischaemic stroke, 5-fold for myocardial infarction (MI), and 10-fold for acute pancreatitis. Furthermore, Mendelian randomization studies indicate that elevated TG-rich lipoproteins are causally related to increased risk of ASCVD and even all-cause mortality. While genetic and epidemiological data strongly indicate that TG-rich lipoproteins are causally linked to ASCVD, intervention data are ambiguous. Fibrates, niacin and low-dose omega-3 fatty acids have all been used in outcome trials, but have failed to demonstrate clear benefit in combination with statins. Whether the lack of additional benefit relates to methodological issues or true failure is indeterminate. Importantly, a recent intervention trial evaluating a high dose of eicosapentaenoic-acid showed clear benefit. Thus, REDUCE-IT evaluated the effect of icosapent ethyl (4 g/day) on cardiovascular outcomes in 8179 high-risk patients with moderate TG elevation on statin therapy. Over a median duration of 4.9 years, the relative risk for the primary endpoint (composite of cardiovascular death, non-fatal MI, non-fatal stroke, coronary revascularization, or unstable angina) was reduced by 25% (absolute risk 17.2% vs. 22.0%; P < 0.0001; number needed to treat 21). High-dose icosapent ethyl intervention therefore confers substantial cardiovascular benefit in high-risk patients with moderate hypertriglyceridaemia on statin therapy.

Circulating Rather Than Intestinal PCSK9 (Proprotein Convertase Subtilisin Kexin Type 9) Regulates Postprandial Lipemia in Mice

OBJECTIVE

Increased postprandial lipemia (PPL) is an independent risk factor for atherosclerotic cardiovascular diseases. PCSK9 (Proprotein convertase subtilisin kexin type 9) is an endogenous inhibitor of the LDLR (low-density lipoprotein receptor) pathway. We previously showed that PCSK9 inhibition in mice reduces PPL. However, the relative contribution of intracellular intestinal PCSK9 or liver-derived circulating PCSK9 to this effect is still unclear. Approach and Results: To address this issue, we generated the first intestine-specific Pcsk9-deficient (i-Pcsk9^-/-) mouse model. PPL was measured in i-Pcsk9^-/- as well as in wild-type and streptozotocin-induced diabetic mice following treatment with a PCSK9 monoclonal antibody (alirocumab). Blocking the circulating form of PCSK9 with alirocumab significantly reduced PPL, while overexpressing human PCSK9 in the liver of full Pcsk9^-/- mice had the opposite effect. Alirocumab regulated PPL in a LDLR-dependent manner as this effect was abolished in Ldlr^-/- mice. In contrast, i-Pcsk9^-/- mice did not exhibit alterations in plasma lipid parameters nor in PPL. Finally, PPL was highly exacerbated by streptozotocin-induced diabetes mellitus in Pcsk9^+/+ but not in Pcsk9^-/- mice, an effect that was mimicked by the use of alirocumab in streptozotocin-treated Pcsk9^+/+ mice.

CONCLUSIONS

Taken together, our data demonstrate that PPL is significantly altered by full but not intestinal PCSK9 deficiency. Treatment with a PCSK9 monoclonal antibody mimics the effect of PCSK9 deficiency on PPL suggesting that circulating PCSK9 rather than intestinal PCSK9 is a critical regulator of PPL. These data validate the clinical relevance of PCSK9 inhibitors to reduce PPL, especially in patients with type 2 diabetes mellitus.

Antidyslipidemic and Antioxidant Activities of Matricaria pubescens (Desf.) Shultz. in Streptozotocin-Induced Diabetic Rats

AIMS

The study aimed to evaluate the antihyperlipidemic and antioxidant activities of Matricaria pubescens.

BACKGROUND

Matricaria pubescens (Desf.) Shultz belongs to Asteraceae family and it is commonly used traditionally for handling diabetes mellitus.

OBJECTIVE

The objective of this study was to assess the antioxidant activity of Matricaria pubescens (Desf.) Shultz and its effect on lipid and lipoprotein profile in normal and streptozotocin-induced diabetic rats.

METHODS

The effect of repeated (7 days of treatment) oral administration of the aqueous extracts of aerial part of Matricaria pubescens (MPAE) at a dose of 40 mg/kg on lipid and lipoprotein profile was examined in normal and streptozotocin-induced diabetic rats. Furthermore, a preliminary phytochemical screening and the quantification of phenolic, flavonoid and tannin contents as well as the antioxidant activity using two methods (FRAP and ABTS) were carried out.

RESULTS

MPAE demonstrated a potent antidyslipidemic effect in diabetic rats by reducing serum levels of triglycerides, total cholesterol and Low-Density Lipoprotein (LDL). In addition, the results showed that the extract is rich in several phytochemical compounds and revealed an important antioxidant activity.

CONCLUSION

In summary, this study proved that Matricaria pubescens (Desf.) Shultz. has a favorable effect on diabetic dyslipidemia.