👤 Alan K Burnett

Acute myeloid leukemia (AML) is a complex hematologic malignancy with multiple disease subgroups defined by somatic mutations and heterogeneous outcomes. Although genome-wide association studies (GWAS) have identified a small number of common genetic variants influencing AML risk, the heritable component of this disease outside of familial susceptibility remains largely undefined. Here, we perform a meta-analysis of 4 published GWAS plus 2 new GWAS, totaling 4710 AML cases and 12 938 controls. We identify a new genome-wide significant risk locus for pan-AML at 2p23.3 (rs4665765; P = 1.35 × 10-8; EFR3B, POMC, DNMT3A, and DNAJC27), which also significantly associates with patient survival (P = 6.09 × 10-3). Our analysis also identifies 3 new genome-wide significant risk loci for disease subgroups, including AML with deletions of chromosome 5 and/or 7 at 1q23.3 (rs12078864; P = 7.0 × 10-10; DUSP23) and cytogenetically complex AML at 2q33.3 (rs12988876; P = 3.28 × 10-8; PARD3B) and 2p21 (rs79918355; P = 1.60 × 10-9; EPCAM). We also investigated loci previously associated with the risk of clonal hematopoiesis (CH) or CH of indeterminate potential and identified several variants associated with the risk of AML. Our results further inform on AML etiology and demonstrate the existence of disease subgroup specific risk loci. Show less

Lipoprotein(a) [Lp(a)] is an independent, inherited risk factor for atherosclerotic cardiovascular disease (ASCVD) and aortic stenosis. Lp(a) is an LDL-like particle containing apoB-100 and apo(a). Lifestyle changes and statin therapy lower LDL-cholesterol and apoB, but do not reduce Lp(a), whereas PCSK9 inhibitors exert a modest effect. There are currently no approved Lp(a)-lowering drugs, although several are at various phases of clinical development. We discuss the role of Lp(a) as a therapeutic target, describe the development, pharmacodynamics, pharmacokinetics, and metabolism of zerlasiran, a small interfering RNA (siRNA) targeting Lp(a), and report the findings of recent clinical trials. The GalNAc-conjugated siRNA zerlasiran reduces Lp(a) by targeting hepatic apo(a) synthesis and subsequent assembly of Lp(a), with comparable efficacy to other Lp(a)-lowering therapies in phase II development. Its long half-life, infrequent dosing, and potentially lower cost, together with its favorable safety and tolerability profile, make zerlasiran a promising candidate. However, long-term studies are needed to assess its impact on major adverse cardiovascular events and safety in diverse patient populations, and across different clinical settings. The phase III cardiovascular outcome study has not commenced. Show less

Lipoprotein(a) [Lp(a)] is an LDL-like particle, which is synthesized and assembled in the liver, and whose plasma levels are strongly associated with, and considered to be causative of, atherosclerotic cardiovascular disease (ASCVD). Several promising pharmacological therapies that directly target Lp(a) are under development. We discuss the role of Lp(a) in ASCVD, describe the pharmacodynamics, pharmacokinetics, and metabolism of muvalaplin, an oral Lp(a) inhibitor, as well as reporting on the findings of the phase II KRAKEN trial in adults at high cardiovascular risk with elevated Lp(a). Muvalaplin is the first oral small molecule inhibitor of Lp(a) formation for the treatment of elevated Lp(a). In KRAKEN, muvalaplin significantly reduced Lp(a) levels in high-risk patients by up to 70% and 85.5% by traditional and novel isoform-insensitive intact assays, respectively. Safety and tolerability studies reported to date are promising, with minimal effect on plasminogen activity that was independent of dose. In terms of patient convenience and adherence, the oral dosing of muvalaplin may confer practical advantages over injectable Lp(a)-lowering therapies. The results of the MOVE-Lp(a) phase III trial, which is evaluating the effect of muvalaplin on cardiovascular outcomes in high-risk patients with elevated Lp(a), are eagerly awaited. Show less

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, by preventing the degradation of LDL receptors, either through interference in the binding of PCSK9 to LDL receptors or through silencing of PCSK9 at a molecular level, have revolutionized lipid-lowering treatment and offer the opportunity to further improve clinical outcomes for patients with hypercholesterolemia. We discuss the role of PCSK9 as a therapeutic target for hypercholesterolemia, describe the pharmacodynamics, pharmacokinetics, and metabolism of recaticimab, and report the recent clinical trials with this 'humanized' IgG1 monoclonal antibody (mAb) against PCSK9. Recaticimab has a high affinity for PCSK9 that confers a prolonged duration of action. Recaticimab durably decreases LDL-cholesterol, non-HDL-cholesterol and apoB, but can also lower Lp(a). Recaticimab may offer advantages over current mAbs in clinical use in terms of its long half-life, dosing interval of up to 12 weeks, and potentially a lower cost; however, long-term concerns regarding immunogenicity remain. Longer-term studies in a variety of more diverse patient cohorts will be needed to further evaluate the efficacy, safety, and durability of recaticimab and to ascertain the optimal dosing schedule for cardiovascular outcome studies. Show less

Apolipoprotein (apo)C-III, a key regulator of plasma triglyceride (TG) levels, is a prime candidate for the treatment of hypertriglyceridemia (HTG), prevention of acute pancreatitis, and reduction of future atherosclerotic cardiovascular disease (ASCVD) events. We discuss the role of apoC-III as a therapeutic target for HTG, describe the pharmacodynamics, pharmacokinetics, and metabolism of olezarsen, as well as report on the findings of recent clinical trials with this liver-directed Olezarsen, a GalNac-conjugated ASO targeting apoC-III, can reduce TG levels by ~ 50% in patients with extreme HTG due to familial chylomicronemia syndrome, as well as in patients with moderate HTG. Attention is now focused on whether olezarsen reduces ASCVD risk in patients with moderate and severe HTG. While olezarsen does cause elevations in liver enzymes, these changes are not clinically meaningful, and are not associated with thrombocytopenia, an issue with its predecessor, volanesorsen. The need for 4-weekly administration puts olezarsen at a disadvantage to competing injectables. Results from the CORE, CORE2, and ESSENCE phase III clinical trials in patients with severe HTG, expected in the second half of 2025, will help determine the requirement for a larger cardiovascular outcomes trial. Show less

The brain renin-angiotensin system (RAS) is implicated in control of blood pressure (BP), fluid intake, and energy expenditure (EE). Angiotensin II (ANG II) within the arcuate nucleus of the hypothalamus contributes to control of resting metabolic rate (RMR) and thereby EE through its actions on Agouti-related peptide (AgRP) neurons, which also contribute to EE control by leptin. First, we determined that although leptin stimulates EE in control littermates, mice with transgenic activation of the brain RAS (sRA) exhibit increased EE and leptin has no additive effect to exaggerate EE in these mice. These findings led us to hypothesize that leptin and ANG II in the brain stimulate EE through a shared mechanism. Because AgRP signaling to the melanocortin MC Show less

One genetic cause of markedly low plasma concentrations of apolipoprotein (apo) B and low density lipoprotein (LDL)-cholesterol is familial hypobetalipoproteinemia. We aimed to determine the molecular basis for the marked hypocholesterolemia consistent with heterozygous familial hypobetalipoproteinemia in a black female subject of Xhosa lineage. Coding regions of APOB, MTTP, PCSK9,ANGPTL3, SAR1B and APOC3 were sequenced, and APOE was genotyped. COS-7 cells were transfected with plasmids containing apoB variants. Western blotting was used to detect cellular and secreted apoB, and co-immunoprecipitation performed to assess binding with the microsomal triglyceride transfer protein (MTP). Sequence analysis of the APOB gene revealed her to be heterozygous for two novel variants, c.751G>A (A224T) and c.2854G>C (V925L). She was also homozygous for the APOEε2 allele, and did not carry a PCSK9 loss-of-function mutation. Although Ala(224) is within the postulated MTP binding region in apoB, it is not conserved among mammalian species. Subsequent genotyping showed that Ala224Thr is found in a southern African population (n=654) with an allele frequency of 1.15% and is not associated with plasma lipid levels. Val(925), like Ala(224), is within the N-terminal 1000 amino acids required for lipoprotein assembly, but was not found in the population screen. However, in vitro studies showed that apoB V925L did not affect apoB48 production or secretion nor have a deleterious effect on MTP interaction with apoB. Taken together, this suggests that the hypocholesterolemia in our case may be a result of being homozygous for APOEε2 with a low baseline cholesterol. Show less

The effects of supplementing diets with n-3 alpha-linolenic acid (ALA) and docosahexaenoic acid (DHA) on plasma metabolites, carcass yield, muscle n-3 fatty acids and liver messenger RNA (mRNA) in lambs were investigated. Lambs (n = 120) were stratified to 12 groups based on body weight (35 ± 3.1 kg), and within groups randomly allocated to four dietary treatments: basal diet (BAS), BAS with 10.7 % flaxseed supplement (Flax), BAS with 1.8 % algae supplement (DHA), BAS with Flax and DHA (FlaxDHA). Lambs were fed for 56 days. Blood samples were collected on day 0 and day 56, and plasma analysed for insulin and lipids. Lambs were slaughtered, and carcass traits measured. At 30 min and 24 h, liver and muscle samples, respectively, were collected for determination of mRNA (FADS1, FADS2, CPT1A, ACOX1) and fatty acid composition. Lambs fed Flax had higher plasma triacylglycerol, body weight, body fat and carcass yield compared with the BAS group (P < 0.001). DHA supplementation increased carcass yield and muscle DHA while lowering plasma insulin compared with the BAS diet (P < 0.01). Flax treatment increased (P < 0.001) muscle ALA concentration, while DHA treatment increased (P < 0.001) muscle DHA concentration. Liver mRNA FADS2 was higher and CPT1A lower in the DHA group (P < 0.05). The FlaxDHA diet had additive effects, including higher FADS1 and ACOX1 mRNA than for the Flax or DHA diet. In summary, supplementation with ALA or DHA modulated plasma metabolites, muscle DHA, body fat and liver gene expression differently. Show less

Hypertriglyceridaemia is a common biochemical abnormality that can be due to primary causes or, more commonly, secondary causes. Moderate hypertriglyceridaemia is a risk factor for cardiovascular disease and can develop into severe hypertriglyceridaemia which is a risk factor for acute pancreatitis. Familial chylomicronaemia is a rare autosomal recessive disorder, usually diagnosed in childhood and is characterized by marked hypertriglyceridaemia and biochemical deficiency of lipoprotein lipase (LPL), apolipoprotein (apo) C-II, homozygous (or compound heterozygous) gene mutations in LPL or more rarely, APOC2. Recently, loss-of-function mutations in the APOA5 gene have been reported in patients with severe hypertriglyceridaemia in whom LPL or APOC2 mutations were not found. We describe the clinical features and genetic analysis of three patients with severe hypertriglyceridaemia including novel mutations LPL c.464T>C (p.Leu155Pro) and APOA5 c.823C>T (p.Gln275*). Show less