Apolipoprotein B as a Marker of Familial Hyperlipoproteinemia

The efficacy and safety of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors combined with statins in patients with hypercholesterolemia: a network meta-analysis

Background

In recent years, the position of PCSK9 inhibitors as adjuvant therapy to statins in guidelines has further improved. However, there remained a dearth of direct comparative studies among different PCSK9 inhibitors. Therefore, this study aimed to conduct a network meta-analysis to evaluate the efficacy and safety of different PCSK9 inhibitors combined with statins.

Methods

A comprehensive literature search was conducted from the study's inception to 12 November 2023, encompassing multiple online databases including PubMed, Embase, Cochrane Central, Web of Science, and ClinicalTrials.gov to obtain relevant randomized controlled trials. Frequentist network meta-analysis was employed to compare the efficacy and safety of different PCSK9 inhibitors. The efficacy endpoints were low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (ApoB), and lipoprotein (a) (Lp(a)). The safety endpoints were any adverse events (AE), severe adverse events (SAE), AE leading to treatment discontinuation, and injection-site reaction.

Results

Compared with placebo and ezetimibe, all PCSK9 inhibitors demonstrated significant reductions in LDL-C levels. Notably, evolocumab exhibited the most pronounced effect with a treatment difference of -63.67% (-68.47% to -58.87%) compared with placebo. Regarding dosage selection for evolocumab, the regimen of 140 mg Q2W (-69.13%, -74.55% to -63.72%) was superior to 420 mg QM (-61.51%, -65.97% to -57.05%). Based on rankings and P-scores analysis, tafolecimab 150 mg Q2W demonstrated superior efficacy in reducing ApoB levels (-61.70%, -84.38% to -39.02%) and Lp(a) levels (-43%, 30%, -68%, 81% to -17%, 79%). Furthermore, the safety profile of PCSK9 inhibitors was favorable with no increase in the incidence of AE, SAE, or AE leading to treatment discontinuation; however, alirocumab, inclisiran, and tafolecimab may potentially entail a potential risk associated with injection-site reactions.

Conclusion

Compared with placebo and ezetimibe, PCSK9 inhibitors can significantly reduce LDL-C, ApoB, and Lp(a) when combined with statins to treat hypercholesterolemia. Furthermore, PCSK9 inhibitors and ezetimibe exhibit similar safety profiles.

Systematic Review Registration

[PROSPERO], identifier [CRD42023490506].

Identification of two common variants contributing to serum apolipoprotein B levels in Mexicans

BACKGROUND AND PURPOSE

Although the Mexican population has a high predisposition to dyslipidemias and premature coronary artery disease, this population is underinvestigated for the genetic factors conferring the high susceptibility. This study attempted to determine these genetic factors.

METHODS AND RESULTS

First, we investigated apolipoprotein B (apoB) levels in Mexican extended families with familial combined hyperlipidemia using a two-step testing strategy. In the screening step, we screened 5721 single-nucleotide polymorphisms (SNPs) for linkage signals with apoB. In the test step, we analyzed the 130 SNPs residing in regions of suggestive linkage signals for association with apoB. We identified significant associations with two SNPs (ie, rs1424032 [P=6.07x10(-6)] and rs1349411 [P=2.72x10(-4)]) that surpassed the significance level for the number of tests performed in the test step (P<3.84x10(-4)). Second, these SNPs were tested for replication in Mexican hyperlipidemic case-control samples. The same risk alleles as in the families with familial combined hyperlipidemia were significantly associated (P<0.05) with apoB in the case-control samples. The rs1349411 resides near the apoB messenger RNA editing enzyme (APOBEC1) involved in the processing of APOB messenger RNA in the small intestine. The rs1424032 resides in a highly conserved noncoding region predicted to function as a regulatory element.

CONCLUSIONS

We identified two novel variants, rs1349411 and rs1424032, for serum apoB levels in Mexicans.