Tafolecimab in Chinese patients with non-familial hypercholesterolemia (CREDIT-1): a 48-week randomized, double-blind, placebo-controlled phase 3 trial.

Background: Tafolecimab, a fully human proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibody developed for the treatment of hypercholesterolemia, demonstrated robust lipid-lowering efficacy and favorable safety in previous short-term studies. We aimed to assess the long-term efficacy and safety of tafolecimab in Chinese non-familial hypercholesterolemia (non-FH) patients. Methods: Non-FH patients at high or very-high cardiovascular risk with screening low-density lipoprotein cholesterol (LDL-C) level ≥1.8 mmol/L or non-FH patients with screening LDL-C level ≥3.4 mmol/L and on stable lipid-lowering therapy for at least 4 weeks, were randomized in a 2:2:1:1 ratio to receive subcutaneous tafolecimab 450 mg Q4W, tafolecimab 600 mg Q6W, placebo 450 mg Q4W, or placebo 600 mg Q6W, respectively, in the 48-week double-blind treatment period. The primary endpoint was the percent change from baseline to week 48 in LDL-C levels. Findings: A total of 618 patients were randomized and 614 patients received at least one dose of tafolecimab (n = 411) or placebo (n = 203). At week 48, tafolecimab induced significant reductions in LDL-C levels (treatment differences versus placebo [on-treatment estimand]: -65.0% [97.5% CI: -70.2%, -59.9%] for 450 mg Q4W; -57.3% [97.5% CI: -64.0%, -50.7%] for 600 mg Q6W; both P < 0.0001). Significantly more patients treated with tafolecimab achieved ≥50% LDL-C reductions, LDL-C < 1.8 mmol/L, and LDL-C < 1.4 mmol/L than placebo group at both dose regimens (all P < 0.0001). Furthermore, tafolecimab significantly reduced non-HDL-C, apolipoprotein B, and lipoprotein(a) levels. The most commonly-reported treatment emergent adverse events in the tafolecimab groups included upper respiratory infection, urinary tract infection and hyperuricemia. Interpretation: Tafolecimab dosed at 450 mg Q4W and 600 mg Q6W was safe and showed superior lipid-lowering efficacy versus placebo, providing a novel treatment option for Chinese hypercholesterolemia patients. Funding: This study was sponsored by Innovent Biologics, Inc.

Tafolecimab in Chinese Patients With Hypercholesterolemia (CREDIT-4): A Randomized, Double-Blind, Placebo-Controlled Phase 3 Trial.

Background: Tafolecimab is a novel fully human proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibody, developed for the treatment of hypercholesterolemia. Objectives: The purpose of this study was to assess the efficacy and safety of tafolecimab in Chinese patients at high or very high cardiovascular risk with hypercholesterolemia. Methods: Patients with diagnoses of heterozygous familial hypercholesterolemia (HeFH) by the Simon Broome criteria or at high or very high cardiovascular risk with nonfamilial hypercholesterolemia, with screening low-density lipoprotein cholesterol (LDL-C) level ≥1.8 mmol/L, were randomized 2:1 to receive tafolecimab or placebo 450 mg every 4 weeks (Q4W) in the 12-week double-blind treatment period. The primary endpoint was the percent change from baseline to week 12 in LDL-C levels. Results: A total of 303 patients were enrolled and received at least 1 dose of tafolecimab (n = 205) or placebo (n = 98). The least squares mean percent change in LDL-C level from baseline to week 12 was -68.9% (SE 1.4%) in the tafolecimab group and -5.8% (1.8%) in the placebo group (difference: -63.0%; [95% CI: -66.5% to -59.6%]; P < 0.0001). More patients treated with tafolecimab achieved ≥50% LDL-C reductions, LDL-C <1.8 mmol/L, and LDL-C <1.4 mmol/L at week 12 than did those in the placebo group (all P < 0.0001). Furthermore, tafolecimab markedly reduced non-HDL-C, apolipoprotein B, and lipoprotein(a) levels. During the double-blind treatment period, the most commonly reported adverse events included urinary tract infection (5.9% with tafolecimab vs 4.1% with placebo) and hyperuricemia (3.4% vs 4.1%). Conclusions: Tafolecimab was safe and showed robust lipid-lowering efficacy in Chinese patients at high or very high cardiovascular risk with hypercholesterolemia. (A Study of IBI306 in Participants With Hypercholesterolemia; NCT04709536).

Exosomes derived from cardiomyocytes promote cardiac fibrosis via myocyte-fibroblast cross-talk.

Cardiac fibrosis is primarily mediated by activated fibroblasts. However, cardiomyocytes have also been implicated in facilitating the fibrotic response. We aimed to explore how cardiomyocyte-derived exosomes affect fibroblasts. We measured cardiac-specific microRNA levels in two rat models of cardiac fibrosis to find out which microRNA was involved in the common mechanisms of cardiac fibrosis. Then, we isolated exosomes from cardiomyocytes and measured their effects on fibroblast proliferation and differentiation into myofibroblasts. We used a microRNA antagomir and an AAV9 microRNA sponge delivery system to inhibit cardiac microRNA in vivo. We then transfused cardiomyocyte-derived exosomes into normal rats to determine the functional effects of the exosomes. miR-208a was upregulated in cardiomyocytes and cardiomyocyte-derived exosomes from both models of cardiac fibrosis and could be transferred into cardiac fibroblasts via the exosomes. The miR-208a-containing exosomes contributed to increased fibroblast proliferation and differentiation into myofibroblasts, an effect that was attenuated by the miR-208a antagomir. When miR-208a was inhibited in vivo, cardiac function improved and cardiac fibrosis was alleviated in post-myocardial-infarction rats. The transfusion of miR-208a-containing exosomes into normal rats resulted in worsened cardiac function. We identified Dyrk2 as the target gene of miR-208a. Cardiomyocytes participate in cardiac fibrosis by secreting exosomes containing miR-208a, which increases fibroblast proliferation and differentiation into myofibroblasts.

Intramyocardial injection of thioredoxin 2-expressing lentivirus alleviates myocardial ischemia-reperfusion injury in rats.

The aim of this study is to explore the role of thioredoxin-2 (Trx2) in autophagy and apoptosis during myocardial ischemia-reperfusion (I/R) injury in vivo. In the study, adult male Sprague-Dawley rats were assigned to four groups at random and pretreated with normal saline (sham operation and I/R groups) and either a control lentivirus (Lv-GFP-N) or one expressing Trx2 (Lv-GFP-Trx2). Sevendays after pretreatment, rat MIRI models were produced via occlusion of the left anterior descending coronary artery for 30 min followed by reperfusion for 6 h. Hearts and blood were harvested to assess efficiency of lentivirus transfection via immunofluorescence staining, quantitative RT-PCR and western blotting, oxidative stress via the malondialdehyde level and superoxide dismutase activity, myocardial damage via myocardial enzymelevels and histopathological staining, myocardial apoptosis via TUNEL assays and western blotting, and myocardial autophagy viawestern blotting. Our results showed thatthe delivery of Lv-GFP-Trx2 into the myocardium remarkably increased Trx2 expression. The upregulation of Trx2 contributed to alleviation of oxidative stress, attenuation of myocardial histological damage, reduced leakage of myocardial enzyme and decrease in infarct size. Moreover, the overexpression of Trx2 was significantly associated with thedecreased incidence of apoptosis via ASK1-dependent intrinsic mitochondrial apoptotic pathwayand autophagy via the mammalian target of rapamycin (mTOR) pathway. The study indicates that upregulation of Trx2 protectsthe myocardium from MIRI and isinvolved inthe inhibition of apoptosis and autophagy. Therefore, Trx2 isa promising therapeutic strategy for attenuating MIRI.

Thioredoxin-2 protects against oxygen-glucose deprivation/reperfusion injury by inhibiting autophagy and apoptosis in H9c2 cardiomyocytes.

The aim of this study is to examine the role of thioredoxin-2 (Trx2) in autophagy and apoptosis during myocardial ischemia-reperfusion (I/R) injury in vitro. We employed the oxygen-glucose deprivation and reperfusion (OGD/R) model of H9c2 cells and used lentiviral infection to overexpress Trx2. H9c2 cell viability and injury assays were conducted using a Cell Counting Kit-8 (CCK-8) and alactate dehydrogenase (LDH) kit. The effects of Trx2 on autophagy and apoptosis were measured by transmission electron microscopy (TEM), western blot, and flow cytometry. Our results showed that the expression of Trx2 was significantly decreased at reperfusion 6 h after OGD 12 h treatment. Trx2 overexpression inhibited autophagy in H9c2 cells subjected to OGD/R. As the underlying mechanisms, both Akt kinase/the mammalian target of rapamycin (Akt/mTOR) and AMP-activated protein kinase (AMPK)/mTOR signaling pathways were involved in the regulation of Trx2 during autophagy, which was also mediated by reactive oxygen species (ROS). 3-methyladenine (3-MA), an inhibitor of autophagy, not only suppressed OGD/R-induced autophagy but also decreased apoptosis. As a classical autophagy sensitizer, rapamycin (Rapa) augmented autophagy as well as apoptosis. Additionally, we further demonstrated that Trx2 could alleviate OGD/R-induced apoptosis via mitochondrion-mediated intrinsic apoptotic pathway. In summary, our data indicated that Trx2 protects cardiomyocytes under OGD/R by inhibiting autophagy and apoptosis. Trx2 may be a crucial regulatory protein during I/R-induced cardiomyocyte injury and death.

Exosomes derived from cardiac telocytes exert positive effects on endothelial cells.

Telocytes are novel cells that have been documented in the interstitium of multiple organs; however, their role in the heart remains unclear. This study aimed to identify cardiac telocytes by their morphological and molecular features and investigate whether their exosomes affect cardiac endothelial cells. To this end, rat cardiac telocytes were cultured and stained with methylene blue, Janus Green B, and MitoTracker green, or with antibodies for established cell surface markers, and examined by microscopy. In addition, telocyte organelles and exosome release were examined by transmission electron microscopy. To investigate exosome functions, we isolated exosomes from telocytes and co-cultured them with endothelial cells in vitro, as well as transfusing them into a rat model of myocardial infarction. We confirmed that cultured telocytes exhibit normal characteristics, including long, thin prolongations with a moniliform appearance, as well as positive expression of c-Kit, CD34, and vimentin. Furthermore, we observed mitochondria throughout the cell body and telopodes, and found that telocytes actively secrete exosomes. Interestingly, endothelial cells cultured with telocyte supernatants or exosomes exhibited increased proliferation, migration, and formation of capillary-like structures, and these effects were attenuated when exosomes were depleted from telocyte supernatants. Finally, treating myocardial infarction-induced rats with telocyte exosomes resulted in decreased cardiac fibrosis, improved cardiac function, and increased angiogenesis. Taken together, our results provide novel insight into cardiac telocytes, suggesting that they communicate with neighboring endothelial cells via exosome secretion and that these exosomes exert potentially beneficially effects.