Inhibition Of Proprotein Convertase Research Articles

Primary disorders of lipid metabolism: their place in current dyslipidemia guidelines and treatment innovations

According to current guidelines, the selection and intensity of lipid-effective therapies are based on the risk to be treated. The sole clinical categories of primary and secondary prevention of cardiovascular diseases result in over- and under-treatment, which may be acontributory cause of incomplete implementation of current guidelines in everyday practice. For the extent of benefit in cardiovascular outcome studies with lipid-lowering drugs, the importance of dyslipdemia for the pathogenesis of atherosclerosis-related diseases is crucial. Primary lipid metabolism disorders are characterized by life-long increased exposure to atherogenic lipoproteins. This article describes the relevance of new data for low density lipoprotein-effective therapy: inhibition of proprotein convertase subtilisin/kexin type9 (PCSK9), adenosine triphosphate (ATP) citrate lyase with bempedoic acid, and ANGPTL3 with special consideration of primary lipid metabolism disorders, which are insufficiently taken into account, or not taken into account at all, in current guidelines. This is due to their apparently low prevalence rate and thus the lack of large outcome studies. The authors also discuss the consequences of increased lipoprotein(a), which cannot be sufficiently reduced until the ongoing intervention studies examining antisense oligonucleotides and small interfering RNA (siRNA) against apolipoprotein(a) are completed. Another challenge in practice is the treatment of rare, massive hypertriglyceridemia, especially with the aim of preventing pancreatitis. For this purpose, the apolipoprotein C3 (ApoC3) antisense oligonucleotide volenasorsen is available, which binds to the mRNA for ApoC3 and lowers triglycerides by around three quarters.

2023 Update on European Atherosclerosis Society Consensus Statement on Homozygous Familial Hypercholesterolaemia: new treatments and clinical guidance.

This 2023 statement updates clinical guidance for homozygous familial hypercholesterolaemia (HoFH), explains the genetic complexity, and provides pragmatic recommendations to address inequities in HoFH care worldwide. Key strengths include updated criteria for the clinical diagnosis of HoFH and the recommendation to prioritize phenotypic features over genotype. Thus, a low-density lipoprotein cholesterol (LDL-C) >10 mmol/L (>400 mg/dL) is suggestive of HoFH and warrants further evaluation. The statement also provides state-of-the art discussion and guidance to clinicians for interpreting the results of genetic testing and for family planning and pregnancy. Therapeutic decisions are based on the LDL-C level. Combination LDL-C-lowering therapy-both pharmacologic intervention and lipoprotein apheresis (LA)-is foundational. Addition of novel, efficacious therapies (i.e. inhibitors of proprotein convertase subtilisin/kexin type 9, followed by evinacumab and/or lomitapide) offers potential to attain LDL-C goal or reduce the need for LA. To improve HoFH care around the world, the statement recommends the creation of national screening programmes, education to improve awareness, and management guidelines that account for the local realities of care, including access to specialist centres, treatments, and cost. This updated statement provides guidance that is crucial to early diagnosis, better care, and improved cardiovascular health for patients with HoFH worldwide.

The N-Acetylgalactosamine-conjugated small interfering RNA inclisiran can be coadministered safely with atorvastatin in cynomolgus monkeys resulting in additive low-density lipoprotein cholesterol reductions.

Inclisiran, a small interfering RNA, selectively inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9) synthesis in the liver and has been shown to reduce low-density lipoprotein cholesterol (LDL-C) by ≥50% in patients with hypercholesterolemia receiving maximally tolerated statins. The toxicokinetic, pharmacodynamic, and safety profiles of inclisiran when coadministered with a statin were characterized in cynomolgus monkeys. Six cohorts of monkeys were administered either atorvastatin (40 mg/kg, reduced to 25 mg/kg during the study, daily, oral gavage), inclisiran (300 mg/kg every 28 days, subcutaneous administration), atorvastatin (40/25 mg/kg) and inclisiran combinations (30, 100, or 300 mg/kg), or control vehicles over 85 days followed by 90 days' recovery. Inclisiran and atorvastatin toxicokinetic parameters were similar in cohorts administered either agent alone or in combination. Inclisiran exposure increased in a dose-proportional manner. At Day 86, atorvastatin increased plasma PCSK9 levels four-fold from pretreatment levels but did not significantly lower serum LDL-C levels. Inclisiran (alone or in combination) reduced PCSK9 (mean decrease 66-85%) and LDL-C (mean decrease 65-92%) from pretreatment levels at Day 86; levels were significantly lower than the control group (p ≤ .05) and remained decreased during the 90-day recovery. Coadministration of inclisiran with atorvastatin resulted in greater reductions in LDL-C and total cholesterol compared with either drug alone. No toxicities or adverse effects were observed in any cohort receiving inclisiran, either alone or in combination. In summary, inclisiran significantly inhibited PCSK9 synthesis and decreased LDL-C in cynomolgus monkeys without increasing the risk of adverse effects when coadministered with atorvastatin.

Proprotein convertase subtilisin/kexin type 9 inhibitors: prospects for cholesterol-lowering therapy in type 2 diabetes

Diabetic dyslipoproteinemia (DLP), characterized by quantitative, qualitative, and kinetic changes in all major circulating lipids, contributes to an increased risk of atherosclerotic cardiovascular disease in patients with type 2 diabetes mellitus (DM). Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) by human monoclonal antibodies is a promising treatment for diabetic DLP. Several drugs differ in their mechanisms of inhibition of PCSK9 activity. The following groups are conditionally distinguished: PCSK9 monoclonal antibodies (anti-PCSK9 monoclonal antibodies): evolocumab, alirocumab, bococizumab (injectable); other injectable medications with different mechanism of actions (inclisiran, SPC4061, SPC5001, adnectin BMS-962476, LIB003, anti-PCSK9 vaccine; anti-PCSK9 vaccine (nanoparticle-based); orally administered drugs (PF-06446846, DS-9001a, SRT3025); cholesteryl ester transfer protein/PCSK9 inhibitors (anacetrapib, evacetrapib, torcetrapib, K-312). This review aims to discuss the role of alirocumab and evolocumab, fully humanized monoclonal antibodies, in the treatment of type 2 DM patients with DLP and to consider their effectiveness and safety. Strategy of search. Scopus, Science Direct (from Elsevier), and PubMed, including the Medline databases, were searched. The following keywords were used: autonomic nervous system, heart rate variability, baroreflex sensitivity, diabetic cardiac autonomic neuropathy, and MeSH terms. A manual search of the bibliography of publications was used to identify research results that could not be found with the online search. Statins are the first line of choice for treating DLP in patients with type 2 DM to reduce the risk of atherosclerotic cardiovascular disease. Ezetimibe is the next drug to be added if patients’ low-density lipoprotein cholesterol levels are higher than acceptable. In cases of failure of the combination of statins with ezetimibe, PCSK9 inhibitor is a reasonable and rational choice. Overall, clinical data suggest that PCSK9 inhibitors are well tolerated and provide a significant reduction in low-density lipoprotein cholesterol levels in type 2 DM patients with DLP in addition to high-intensity statin therapy. The use of PCSK9 inhibitors is not associated with impaired glycemic control or increased risk of diabetes development in individuals without previously diagnosed DM and may prevent or reduce subsequent cardiovascular events.

Phase 2b Randomized Trial of the Oral PCSK9 Inhibitor MK-0616

BackgroundMK-0616 is an oral macrocyclic peptide inhibitor of proprotein convertase subtilisin/kexin type 9 (PCSK9) in development for the treatment of hypercholesterolemia. ObjectivesThis Phase 2b, randomized, double-blind, placebo-controlled, multicenter trial aimed to evaluate the efficacy and safety of MK-0616 in participants with hypercholesterolemia. MethodsThis trial was planned to include 375 adult participants with a wide range of atherosclerotic cardiovascular disease risk. Participants were assigned randomly (1:1:1:1:1 ratio) to MK-0616 (6, 12, 18, or 30 mg once daily) or matching placebo. The primary endpoints included percentage change from baseline in low-density lipoprotein cholesterol (LDL-C) at Week 8 and the proportion of participants with adverse events (AEs) and study intervention discontinuations due to AEs; participants were monitored for AEs for an additional 8 weeks after the 8-week treatment period. ResultsOf the 381 participants randomized, 49% were female, and the median age was 62 years. Among 380 treated participants, all doses of MK-0616 demonstrated statistically significant (P < 0.001) differences in least squares mean percentage change in LDL-C from baseline to Week 8 vs placebo: –41.2% (6 mg), –55.7% (12 mg), –59.1% (18 mg), and –60.9% (30 mg). AEs occurred in a similar proportion of participants in the MK-0616 arms (39.5% to 43.4%) as placebo (44.0%). Discontinuations due to AEs occurred in 2 or fewer participants in any treatment group. ConclusionsMK-0616 demonstrated statistically significant and robust, dose-dependent placebo-adjusted reductions in LDL-C at Week 8 of up to 60.9% from baseline and was well tolerated during 8 weeks of treatment and an additional 8 weeks of follow-up. (A Study of the Efficacy and Safety of MK-0616 [Oral PCSK9 Inhibitor] in Adults With Hypercholesterolemia [MK-0616-008]; NCT05261126)

The First Report of a Real-world Experience With a PCSK9 Inhibitor in a Large Familial Hyperlipidemia and Very-high-risk Middle Eastern Population

Evolocumab, a monoclonal inhibitor of proprotein convertase subtilisin/kexin 9, has been shown to reduce proatherogenic lipoproteins in patients with or without familial hypercholesterolemia (FH), diabetes mellitus, or atherosclerotic cardiovascular disease (ASCVD). We explored the safety profile and clinical effectiveness of evolocumab in an outpatient population of Emirati individuals with FH diagnosed per Dutch Lipid Clinic Network criteria, previous ASCVD, or statin intolerance. This study was a retrospective review of patients initiating evolocumab treatment for any indication at Imperial College London Diabetes Centre between 2017 and 2020. All individuals followed up for at least 90 days or with at least one lipid panel postinitiation were included. Participants were subclassified into primary prevention (no previous ASCVD event, n=81) and secondary prevention (any prior clinical ASCVD event, n=102) groups. Evolocumab was initiated in 183 individuals (mean [SD] age, 51.5 [12.4] years; 51% male); 108 (59%) had a clinical or genetic FH diagnosis, and 70.5% had diabetes mellitus. Statin intolerance was a treatment indication in 60 (32.8%) individuals. At 90 days, substantial reductions in serum LDL-C, triglycerides (TG), and total cholesterol:HDL-C (TC:HDL-C) were observed in both the primary and secondary prevention groups, and both FH and non-FH individuals. In the primary prevention group, median (interquartile range) reduction in LDL-C was 43.7% (10.8%; 63.0%); TG, 15.0% (7.2%; 35.3%); and TC:HDL-C, 31.5% (11.1%; 46.0%). In the secondary prevention group, median (interquartile range) reduction in LDL-C was 48.3% (22%; 70%); TG, 19.6% (1.2%; 32.5%); and TC:HDL-C, 32.6% (14.6%; 46.3%) (all, P < 0.0001). American College of Cardiology/American Heart Association LDL-C targets were consistently achieved in 114 (62.3%) patients during a follow-up of 359 (79-639) days. Nonattainment of the LDL-C target was attributed to nonadherence in 36 (52.2%) patients and discontinuation of treatment in 14 (20.3%) patients. Evolocumab was discontinued in 4 patients because of adverse events. This study is the first from the Middle East and North Africa region that reports the real-world efficacy of evolocumab in a mixed risk population of individuals with FH and other non-FH indications. Clinically meaningful and sustained reductions in LDL-C, TG, and cholesterol ratios were observed after evolocumab initiation. Few adverse events were reported in this predominantly Arabic population, consistent with previous safety reports for evolocumab. Notable strengths of this study include a relatively large cohort, patient heterogeneity and high retention, and a minimum follow-up of 1 year. Despite these strengths, the study has some limitations, including the selection bias due to the retrospective design and absence of comparative group.

401.2: Inhibition of Proprotein Convertase Subtilisin/Kexin Type A (PCSK-9) Among Renal Transplant Recipients: Is It Beneficial For Cases With High Cardiovascular Risk?

401.2: Inhibition of Proprotein Convertase Subtilisin/Kexin Type A (PCSK-9) Among Renal Transplant Recipients: Is It Beneficial For Cases With High Cardiovascular Risk?

6P Sensitization of pancreatic and colorectal cancer to radiotherapy, chemotherapy and inhibition of PD-1 expression by newly developed proprotein convertase inhibitors

The pancreatic ductal adenocarcinoma (PDAC) and advanced colorectal cancer (CRC) have a bad prognosis with delayed diagnosis that significantly impedes the use of therapeutic resection. In these situation, palliative chemotherapy has modest activity, and Immune checkpoint inhibitors or radiotherapy failed to improve survival. The proprotein convertases (PCs) are enzymes involved in the biological activation/maturation of various protein precursors crucial for the malignant phenotype of PDAC and CRC tumors, and the resistance to various anticancer treatments.

MRNA Display Reaches for the Clinic with New PCSK9 Inhibitor.

Merck & Co. recently reported one of the first mRNA display-derived clinical candidates in a bioavailable inhibitor of proprotein convertase subtilisin/kexin type 9 (PCSK9). Herein, we discuss the chemical and pharmacological challenges surmounted in bringing this compound to trials and the current outlook for mRNA display-based therapeutic development.

Furin cleavage is required for swine acute diarrhea syndrome coronavirus spike protein-mediated cell – cell fusion

ABSTRACT Swine acute diarrhea syndrome coronavirus (SADS-CoV) was reported in China in 2017 and is a causative agent of porcine enteric disease. Recent studies indicate that cells from various hosts are susceptible to SADS-CoV, suggesting the zoonotic potential of this virus. However, little is known about the mechanisms through which this virus enters cells. In this study, we investigated the role of furin in SADS-CoV spike (S)-mediated cell – cell fusion and entry. We found that the SADS-CoV S protein induced the fusion of various cells. Cell – cell fusion was inhibited by the proprotein convertase inhibitor dec-RVKR-cmk, and between cells transfected with mutant S proteins resistant to furin cleavage. These findings revealed that furin-induced cleavage of the SADS-CoV S protein is required for cell – cell fusion. Using mutagenesis analysis, we demonstrated that furin cleaves the SADS-CoV S protein near the S1/S2 cleavage site, 446RYVR449 and 543AVRR546. We used pseudotyped viruses to determine whether furin-induced S cleavage is also required for viral entry. Pseudotyped viruses expressing S proteins with a mutated furin cleavage site could be transduced into target cells, indicating that furin-induced cleavage is not required for pseudotyped virus entry. Our data indicate that S cleavage is critical for SADS-CoV S-mediated cell – cell fusion and suggest that furin might be a host target for SADS-CoV antivirals.

†Efficacy and Safety of Inclisiran in Patients with Established Cerebrovascular Disease: Pooled Post hoc Analysis of the Phase 3 ORION-9, ORION-10, and ORION-11 Randomized Controlled Trials

<h3>Lead Author's Financial Disclosures</h3> Wolfgang Koenig, MD has received consulting fees and lecture fees from AstraZeneca, Novartis and Amgen; consulting fees from Pfizer, the Medicines Company, DalCor Pharmaceuticals, Genentech, Esperion, OMEICOS, Novo Nordisk, LIB Therapeutics, Kowa, Corvidia Therapeutics and Daiichi Sankyo; lecture fees from Berlin- Chemie, Bristol-Myers Squibb and Sanofi; and grant support and provision of reagents from Singulex, Abbott, Roche Diagnostics and Dr. Beckmann Pharma. <h3>Study Funding</h3> Novartis Pharma AG, Basel, Switzerland. <h3>Background/Synopsis</h3> Patients with hyperlipidemia and established cerebrovascular disease (CeVD) are at increased risk of future strokes or other cardiovascular events (1). In ischemic stroke survivors, statins and inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce recurrent cardiovascular events, including stroke (2,3). With guidelines advocating increasingly lower low-density lipoprotein cholesterol (LDL-C) goals, adding lipid-lowering therapies to statins may be needed. Inclisiran, a first-in-class small interfering RNA targeting PCSK9 messenger RNA, when added to maximally tolerated statin therapy for patients with established CeVD, may provide further LDL-C lowering, with a convenient, infrequent dosing schedule (4). <h3>Objective/Purpose</h3> To assess the efficacy and safety of inclisiran in patients with established CeVD. <h3>Methods</h3> This was a post hoc analysis of patients with heterozygous familial hypercholesterolemia or atherosclerotic cardiovascular disease or its risk equivalents and established CeVD (ischemic stroke, carotid artery stenosis by angiography or ultrasound greater than 70%, and/or percutaneous or surgical carotid artery revascularization) from ORION-9 (NCT03397121), ORION-10 (NCT03399370), and ORION-11 (NCT03400800), randomized 1:1 to receive inclisiran sodium 300 mg (equivalent to 284mg inclisiran) or placebo at Day 1, Day 90, and 6 monthly thereafter to Day 540. Evaluations included LDL-C percentage change from baseline to Day 510 and corresponding time-averaged percentage change from baseline after Day 90 to Day 540; safety was assessed over 540 days. <h3>Results</h3> Of 202 patients with established CeVD at baseline, 90.0% (99/110) of patients receiving inclisiran and 84.8% (78/92) on placebo reported prior ischemic stroke; others reported prior carotid artery stenosis and/or carotid revascularization (Table 1). Mean (95% CI) placebo- corrected LDL-C percentage change from baseline at Day 510 with inclisiran was −55.2% (−64.5 to −45.9); corresponding time-averaged change from baseline between Days 90 and 540 was −55.2% (−62.4 to −47.9) (P less than 0.0001 for both; Table 2). Treatment-emergent adverse events (TEAEs) and serious TEAEs were more frequent with inclisiran vs placebo. Clinically relevant injection site TEAEs were more frequent with inclisiran (3.6% [4/110]) vs placebo (0% [0/92]) and none was severe. Few patients had clinically relevant laboratory measurements (Table 2). <h3>Conclusions</h3> In patients with established CeVD, twice-yearly dosing with inclisiran (after the initial and 3-month doses) provided a sustained additional LDL-C reduction of ∼55% and a modest increase in mild/moderate injection site TEAEs. The cardiovascular benefits of inclisiran in patients with established CeVD are being evaluated in ongoing trials.

†Efficacy and Safety of Inclisiran in Patients with Polyvascular Disease: Pooled Post hoc Analysis of the phase 3 ORION-9, ORION-10, and ORION-11 Randomized Controlled Trials

<h3>Lead Author's Financial Disclosures</h3> Wolfgang Koenig, MD has received consulting fees and lecture fees from AstraZeneca, Novartis and Amgen; consulting fees from Pfizer, the Medicines Company, DalCor Pharmaceuticals, Genentech, Esperion, OMEICOS, Novo Nordisk, LIB Therapeutics, Kowa, Corvidia Therapeutics and Daiichi Sankyo; lecture fees from Berlin- Chemie, Bristol-Myers Squibb and Sanofi; and grant support and provision of reagents from Singulex, Abbott, Roche Diagnostics and Dr. Beckmann Pharma. <h3>Study Funding</h3> Novartis Pharma AG, Basel, Switzerland. <h3>Background/Synopsis</h3> Approximately 25% of patients with atherosclerotic cardiovascular disease (ASCVD) have polyvascular disease (PVD) involving 2 or more coronary, cerebrovascular, and peripheral artery beds. PVD is an independent predictor of major adverse cardiovascular events (MACE) and death. Agents that inhibit proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce low-density lipoprotein cholesterol (LDL-C) concentrations and MACE incidence in patients with PVD. Inclisiran is a small interfering RNA agent targeting PCSK9 messenger RNA that is well tolerated and provides effective and sustained LDL-C reductions. <h3>Objective/Purpose</h3> To describe the effect of inclisiran vs placebo in patients with and without PVD. <h3>Methods</h3> This was a post hoc analysis of patients with heterozygous familial hypercholesterolemia or ASCVD or its risk equivalents randomized 1:1 to 300mg inclisiran sodium (equivalent to 284mg inclisiran) or placebo at baseline, Day 90, and 6 monthly thereafter in ORION-9 (NCT03397121), ORION-10 (NCT03399370), and ORION-11 (NCT03400800). Evaluations included LDL-C percentage change from baseline to Day 510 and corresponding time-averaged change from Day 90 to Day 540, with both evaluated by PVD presence or absence, and safety over 540 days. <h3>Results</h3> Baseline characteristics for 470 patients (13.6%) with PVD and 2984 (86.4%) without PVD were generally balanced between treatment arms in both groups, with higher cardiovascular risk factors and lower LDL-C concentrations in patients with PVD (Table 1). Mean (95% CI) placebo-corrected LDL-C percentage changes from baseline to Day 510 with inclisiran were −48.9% (−55.6 to −42.2) in patients with PVD and −51.5% (−53.9 to −49.1) in those without (Table 2). Treatment-emergent adverse events (TEAEs) and treatment-emergent serious adverse events (TESAEs) were similar between treatment arms irrespective of PVD status, although reported TESAEs trended higher with PVD in both treatment arms (Table 2). Clinically relevant injection site TEAEs were more frequent with inclisiran vs placebo in both groups; all were mild or moderate. Few patients had clinically relevant laboratory measurements (Table 2). <h3>Conclusions</h3> Twice-yearly dosing with inclisiran (after the initial and 3-month doses) provided effective and sustained LDL-C lowering in patients with ASCVD irrespective of their PVD status, with a safety profile similar to that of placebo except for a modest increase in mainly mild TEAEs at the injection site. Notably, TESAEs were reported more frequently in patients with PVD, which was likely due to their more advanced disease. Since patients with PVD are at high risk of cardiovascular events, intensive LDL-C lowering may be beneficial to reduce this risk.

Chemical Constituents from the Roots and Rhizomes of Sophora tonkinensis and Their Effects on Proprotein Convertase Substilisin/Kexin Type 9 Expression.

This study was conducted to further investigate bioactive molecules from Sophora tonkinensis that can inhibit proprotein convertase substilisin/kexin type 9 (PCSK9) expression. After interpreting NMR spectroscopic data and MS spectral data of all isolates, a new naturally occurring compound, 6-hydroxy-vitexin-2″-O-rhamnoside (7), was identified along with 30 known compounds. The calculation of the gauge-including atomic orbital (GAIO) and electronic circular dichroism (ECD) proposed the absolute configuration of 17 as (2S,3R)-methyl-2-(4-hydroxybenzyl)tartrate by comparing the calculated ECD with experimental data. All isolates were tested for their inhibitory effects on PCSK9 mRNA expression. Of the tested compounds, (+)-isolariciresinol (12) inhibited PCSK9 expression via downregulation of HNF1α and SREBPs.

P-147 Sensitization of pancreatic and colorectal cancer to radiotherapy, chemotherapy, and immune checkpoint inhibitors by newly developed proprotein convertase inhibitors

The pancreatic ductal adenocarcinoma (PDAC) has a bad prognosis with delayed diagnosis that significantly impedes the use of therapeutic resection. Similarly, colorectal cancer (CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place in the liver. A main reason for this situation is the already resistant or newly resistant tumors to all conventional current therapies. Here, we report the re-sensitization of PDAC and CRC cells to chemotherapy, radiotherapy and/or immune checkpoint inhibitors by the newly developed inhibitors that target the activity of the proprotein convertases, enzymes involved in the biological activation/maturation of various protein precursors crucial for the malignant phenotype of PDAC and CRC tumors.

Targeting PCSK9 Ameliorates Graft Vascular Disease in Mice by Inhibiting NLRP3 Inflammasome Activation in Vascular Smooth Muscle Cells.

BackgroundGraft vascular disease (GVD), which limits the long-term survival of patients after solid-organ transplantation, is associated with both immune responses and nonimmune factors, including dyslipidemia. Recent studies have shown that inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9), a U.S. Federal Drug Administration-approved treatment for hyperlipidemia, reduces cardiovascular events, regulates inflammatory responses, and enhances the efficacy of immune checkpoint therapy in cancer treatment through a cholesterol-independent mechanism. However, whether targeting PCSK9 is a potential therapeutic strategy for GVD remains unknown.MethodsSerum samples and grafts were harvested from male mice undergoing abdominal aortic transplantation. The pathological alterations in the aortic grafts were detected by hematoxylin and eosin staining, Verhoeff’s Van Gieson staining, and Masson staining. Inflammatory cell infiltration and proinflammatory cytokine expression in the aortic grafts were detected by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The regulatory effects of PCSK9 on vascular smooth muscle cell (VSMC) migration and proliferation were examined by transwell, EdU, and western blot assays. The effect of Evolocumab, a PCSK9 inhibitor, on GVD in humanized PCSK9 mice was also evaluated.ResultsPCSK9 was upregulated in the serum, grafts, and liver of mice in the allograft group subjected to abdominal aortic transplantation. Pcsk9 knockout significantly reduced vascular stenosis, the intimal hyperplasia area and collagen deposition. Pcsk9 depletion also inhibited macrophage recruitment and the mRNA expression of proinflammatory cytokines in aortic grafts. Furthermore, Pcsk9 knockout suppressed the migration and proliferation of VSMCs, which was related to the inhibition of NLRP3 inflammasome activation. Meanwhile, Evolocumab significantly ameliorated GVD in humanized PCSK9 mice.ConclusionPCSK9 is upregulated in a mouse model of GVD, and Pcsk9 knockout reduces vascular occlusion, suggesting that PCSK9 may be a promising target for the treatment of GVD.

MO972: Impact of Inhibition of Pcsk-9 Among Renal Transplant Recipients with High Cardiovascular Risk

Abstract BACKGROUND AND AIMS Monoclonal antibodies inhibiting proprotein convertase subtilisin/Kexin type A(PCSK-9) have emerged as one of the new cholesterol-lowering agents. It is not evaluated among renal transplant recipients despite its favorable safety profile. We aimed to evaluate the safety and efficacy of evolocumab in reducing lipids and cardiovascular events among risky renal transplant recipients. METHOD About 195 kidney transplant recipients—with high cardiovascular risk (&amp;gt;20)—were enrolled in this randomized controlled study during the period between 6.2017 and 6.2018. Patients who received statin and evolocumab (140 mg/2 weeks, group 1, n = 97) while those who were maintained on statin alone comprised group 2 (n = 98). They were followed up for 24 months. RESULTS The two groups were comparable regarding their demographics (P &amp;gt; 0.05). Before enrollment in the study, post-transplant complications were comparable apart from a higher prevalence of NODAT in group 2 (P = 0.033). Smokers were significantly more prevalent in group 1. Basal graft function was significantly higher in group 1 despite equivalent regimen of immunosuppression in both groups (P &amp;gt; 0.05). Clinically two groups were comparable concerning cardiovascular events and both graft and patient outcomes (P &amp;gt; 0.05). Basal cholesterol was significantly higher in group 1 (5.5 versus 4.7, P &amp;lt; 0.001) which dropped significantly after 3 months (versus12 months in group 2) and thereafter (P = 0.031). We observed that triglycerides in the two groups were comparable (P &amp;gt; 0.05) till the end of the study. CONCLUSION Evolocumab is a promising add on lipid-lowering agent. In high risk renal transplant, earlier reduction of cholesterol was observed in the add-on evolocumab group but without significant positive cardiovascular impact.

PCSK9 inhibition in patients with acute stroke and symptomatic intracranial atherosclerosis: protocol for a prospective, randomised, open-label, blinded end-point trial with vessel-wall MR imaging

IntroductionDual antiplatelet therapy and high-intensity statins are the mainstay treatment in patients with acute stage, symptomatic intracranial atherosclerotic stenosis (ICAS). Alirocumab is a monoclonal antibody that can inhibit proprotein convertase...

Evaluation of the distribution and excretion of [14C]-inclisiran following single subcutaneous administration in cynomolgus monkeys

Inclisiran is a small interfering RNA molecule that was designed to reduce plasma low-density lipoprotein cholesterol (LDL-C) levels by inhibiting proprotein convertase subtilisin/kexin type 9 synthesis in the liver. This study aimed to characterize the tissue distribution and excretion of inclisiran after dosing in monkeys.A single 20 mg/kg subcutaneous injection of [14C]-inclisiran was administered to 12 male cynomolgus monkeys. Plasma concentrations and tissue binding parameters for inclisiran were assessed up to 42 days after injection using liquid scintillation of blood samples and tissue homogenates, as well as quantitative whole-body autoradiography.Radioactivity was highest in the liver at all time points from 24 h onward and remained elevated throughout the entire study period. Radioactivity was also detected in the kidneys and bladder wall, returning to low levels by 24 h. The concentration of radioactivity in the liver (402.97 μg equivalent/g) was 15.7-fold higher than in the kidneys (25.70 μg equivalent/g). Very low amounts of radioactivity were detected in all other tissues examined. The highest radioactivity in tissue homogenates was in the liver and kidney pyramid (327 and 351 μg equivalent/g, respectively).This study confirmed the selective uptake of inclisiran by the liver, indicating that the N-acetylgalactosamine linker allows for selective uptake via the asialoglycoprotein receptors expressed on hepatocytes compared with other tissues that lack asialoglycoprotein receptors. The long tissue retention in the liver supports the infrequent, biannual dosing schedule for inclisiran in the clinic and the temporal disconnect between short-term systemic exposure and sustained lowering of LDL-C.

Ablation of Plasma Prekallikrein Decreases Low-Density Lipoprotein Cholesterol by Stabilizing Low-Density Lipoprotein Receptor and Protects Against Atherosclerosis.

High blood cholesterol accelerates the progression of atherosclerosis, which is an asymptomatic process lasting for decades. Rupture of atherosclerotic plaques induces thrombosis, which results in myocardial infarction or stroke. Lowering cholesterol levels is beneficial for preventing atherosclerotic cardiovascular disease. Low-density lipoprotein (LDL) receptor (LDLR) was used as bait to identify its binding proteins in the plasma, and the coagulation factor prekallikrein (PK; encoded by the KLKB1 gene) was revealed. The correlation between serum PK protein content and lipid levels in young Chinese Han people was then analyzed. To investigate the effects of PK ablation on LDLR and lipid levels in vivo, we genetically deleted Klkb1 in hamsters and heterozygous Ldlr knockout mice and knocked down Klkb1 using adeno-associated virus-mediated shRNA in rats. The additive effect of PK and proprotein convertase subtilisin/kexin 9 inhibition also was evaluated. In addition, we applied the anti-PK neutralizing antibody that blocked the PK and LDLR interaction in mice. Mice lacking both PK and apolipoprotein e (Klkb1-/-Apoe-/-) were generated to assess the role of PK in atherosclerosis. PK directly bound LDLR and induced its lysosomal degradation. The serum PK concentrations positively correlated with LDL cholesterol levels in 198 young Chinese Han adults. Genetic depletion of Klkb1 increased hepatic LDLR and decreased circulating cholesterol in multiple rodent models. Inhibition of proprotein convertase subtilisin/kexin 9 with evolocumab further decreased plasma LDL cholesterol levels in Klkb1-deficient hamsters. The anti-PK neutralizing antibody could similarly lower plasma lipids through upregulating hepatic LDLR. Ablation of Klkb1 slowed the progression of atherosclerosis in mice on Apoe-deficient background. PK regulates circulating cholesterol levels through binding to LDLR and inducing its lysosomal degradation. Ablation of PK stabilizes LDLR, decreases LDL cholesterol, and prevents atherosclerotic plaque development. This study suggests that PK is a promising therapeutic target to treat atherosclerotic cardiovascular disease.

Rationale and design of two trials assessing the efficacy, safety, and tolerability of inclisiran in adolescents with homozygous and heterozygous familial hypercholesterolaemia.

Inclisiran is a small interfering RNA molecule that reduces low-density lipoprotein cholesterol (LDL-C) by inhibition of proprotein convertase subtilisin/kexin type 9. This subcutaneous, twice-yearly administered agent has been shown to effectively and safely lower LDL-C in adult patients with established atherosclerotic cardiovascular disease, adults at high risk for atherosclerotic cardiovascular disease, as well as in adults with heterozygous familial hypercholesterolaemia. With the current, limited treatment options available to reach treatment goals in children with severe heterozygous familial hypercholesterolaemia, homozygous familial hypercholesterolaemia, or statin intolerance, inclisiran could be a valuable new therapeutic option. The objective of these ongoing studies is to investigate the efficacy, safety, and tolerability of inclisiran in adolescents diagnosed with homozygous familial hypercholesterolaemia (ORION-13) or heterozygous familial hypercholesterolaemia (ORION-16). ORION-13 and ORION-16 are both two-part (1-year double-blind inclisiran vs. placebo/1 year open-label inclisiran) multicentre trials including adolescents aged 12 to &lt;18 years diagnosed with familial hypercholesterolaemia. ORION-13 will include ∼12 participants diagnosed with homozygous familial hypercholesterolaemia and ORION-16 will include ∼150 participants diagnosed with heterozygous familial hypercholesteroleamia. The primary endpoint is the percentage change in LDL-C from baseline to Day 330. Secondary efficacy and safety endpoints include changes in other lipid parameters and treatment-emergent adverse events as well as laboratory parameters and vital signs. Exploratory endpoints include individual responsiveness of the participants and change in LDL-C according to the type of underlying causal mutation. https://www.clinicaltrials.gov/. Unique identifier: NCT04659863 (ORION-13) and NCT04652726 (ORION-16).