👤 Richard A Baum

Familial chylomicronemia syndrome (FCS) is a rare genetic disorder associated with extreme hypertriglyceridemia and high risk of acute pancreatitis. Olezarsen-an antisense oligonucleotide targeting hepatic apolipoprotein C3 (APOC3) messenger RNA-reduces triglycerides and may decrease pancreatitis risk. Olezarsen 80 mg once monthly is approved in the United States as an adjunct to diet to reduce triglycerides in adults with FCS. To assess the effect of olezarsen on all-cause healthcare resource utilization (HCRU) and overall experience of patients with genetically identified FCS enrolled in the Balance trial (NCT04568434). Prespecified exploratory endpoints included yearly all-cause hospitalization, total inpatient days, and emergency room visits for patients treated with olezarsen (80 or 50 mg) vs placebo, as well as Patient Global Impression of Change (PGIC). Ad hoc outcomes included length of hospital stay, intensive care unit (ICU) admissions, reasons for HCRU, and all-cause HCRU according to patients' history of acute pancreatitis and for individual olezarsen doses vs placebo. Treatment with olezarsen vs placebo for 1 year was associated with an 84% reduction in all-cause hospitalizations (mean rate ratio [95% CI], 0.16 [0.05, 0.50]), 6.3 fewer total inpatient days (95% CI, -11.09, -1.53), better PGIC scores, shorter length of stay, and numerically fewer ICU admissions. Acute pancreatitis was the most frequent cause of hospitalization. Reduction in all-cause inpatient service utilization was consistent for individual dose groups and in patients with a history of acute pancreatitis. In the Balance study, olezarsen reduced all-cause inpatient service utilization and improved the experience of patients with FCS. Show less

Lipoprotein(a) (Lp[a]) is thought to be the major carrier of oxidized phospholipids (OxPL). OxPL are believed to be a potent driver of inflammation and atherosclerosis. Olpasiran, a small interfering RNA, blocks Lp(a) production by inducing degradation of apolipoprotein(a) messenger RNA. Olpasiran's effects on OxPL and systemic markers of inflammation are not well described. To assess the effects of olpasiran on OxPL, high-sensitivity interleukin 6 (hs-IL-6), and hs-C-reactive protein (hs-CRP) in the OCEAN(a)-DOSE randomized clinical trial. OCEAN(a)-DOSE was an international, multicenter, placebo-controlled, phase 2, dose-finding randomized clinical trial conducted between July 2020 and November 2022. A total of 281 patients with atherosclerotic cardiovascular disease and Lp(a) levels greater than 150 nmol/L were included. Participants were randomized to receive 1 of 4 active subcutaneous doses of olpasiran vs placebo: (1) 10 mg, administered every 12 weeks (Q12W); (2) 75 mg, Q12W; (3) 225 mg, Q12W; or (4) 225 mg, administered every 24 weeks (Q24W). OxPL on apolipoprotein B (OxPL-apoB), hs-CRP, and hs-IL-6 were assessed at baseline, week 36, and week 48 in 272 patients. The primary outcome was placebo-adjusted change in OxPL-apoB from baseline to week 36. Among 272 participants, median (IQR) age was 62 years (56-69), and 86 participants (31.6%) were female. Baseline median (IQR) Lp(a) concentration was 260.3 nmol/L (198.1-352.4) and median (IQR) OxPL-apoB concentration was 26.5 nmol/L (19.7-33.9). The placebo-adjusted mean percentage change in OxPL-apoB from baseline to week 36 was -51.6% (95% CI, -64.9% to -38.2%) for the 10-mg Q12W dose, -89.7% (95% CI, -103.0% to -76.4%) for the 75-mg Q12W dose, -92.3% (95% CI, -105.6% to -78.9%) for the 225-mg Q12W dose, and -93.7% (95% CI, -107.1% to -80.3%) for the Q24W dose (P < .001 for all). These effects were maintained to week 48 (-50.8%, -100.2%, -104.7%, and -85.8%, respectively; P < .001 for all). There was a strong correlation between percentage reduction in Lp(a) and OxPL-apoB for patients treated with olpasiran (r = 0.79; P < .001). Olpasiran did not significantly impact hs-CRP or hs-IL-6 compared with placebo to weeks 36 or 48 (P > .05). In the OCEAN(a)-DOSE multicenter randomized clinical trial, olpasiran led to a significant and sustained reduction in OxPL-apoB but no significant effects on hs-CRP or hs-IL-6. Show less

Familial chylomicronemia syndrome (FCS) is a rare, typically debilitating genetic disorder of extreme hypertriglyceridemia associated with high triglyceride levels and elevated risk for recurrent acute pancreatitis. Diagnosis of FCS is frequently delayed due to its rarity, and treatment options are limited. Patients often report history of acute pancreatitis or associated symptoms, including chronic or recurrent abdominal pain, weakness, and fatigue. The hallmark of chylomicronemia (extreme hypertriglyceridemia) syndromes, including FCS, is extremely high triglyceride levels ≥880 mg/dL (10 mmol/L) resistant to conventional triglyceride-lowering medications including statins, fibrates, and omega-3 fatty acids. Validated clinical scoring tools or genetic testing can support diagnosis. Patients must follow a strict FCS-specific diet <15 to 20 g fat/day. Failure to adhere increases the possibility of recurrent acute and chronic pancreatitis and pancreatic dysfunction. Dietary adherence and long-term disease management are extremely challenging for patients. Multidisciplinary clinical teams can improve patient outcomes and quality of life. Therapies that reduce apolipoprotein C-III, a regulator of triglyceride metabolism, offer an FCS treatment option. Olezarsen, a hepatic-targeted Show less

Hypertriglyceridaemia is associated with increased risk of cardiovascular events. This clinical trial evaluated olezarsen, an N-acetyl-galactosamine-conjugated antisense oligonucleotide targeted to hepatic APOC3 mRNA to inhibit apolipoprotein C-III (apoC-III) production, in lowering triglyceride levels in patients at high risk for or with established cardiovascular disease. A randomized, double-blind, placebo-controlled, dose-ranging study was conducted in 114 patients with fasting serum triglycerides 200-500 mg/dL (2.26-5.65 mmol/L). Patients received olezarsen (10 or 50 mg every 4 weeks, 15 mg every 2 weeks, or 10 mg every week) or saline placebo subcutaneously for 6-12 months. The primary endpoint was the percent change in fasting triglyceride levels from baseline to Month 6 of exposure. Baseline median (interquartile range) fasting triglyceride levels were 262 (222-329) mg/dL [2.96 (2.51-3.71) mmol/L]. Treatment with olezarsen resulted in mean percent triglyceride reductions of 23% with 10 mg every 4 weeks, 56% with 15 mg every 2 weeks, 60% with 10 mg every week, and 60% with 50 mg every 4 weeks, compared with increase by 6% for the pooled placebo group (P-values ranged from 0.0042 to <0.0001 compared with placebo). Significant decreases in apoC-III, very low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B were also observed. There were no platelet count, liver, or renal function changes in any of the olezarsen groups. The most common adverse event was mild erythema at the injection site. Olezarsen significantly reduced apoC-III, triglycerides, and atherogenic lipoproteins in patients with moderate hypertriglyceridaemia and at high risk for or with established cardiovascular disease. NCT03385239. Show less

During animal cell division, an actin-based ring cleaves the cell into two. Problems with this process can cause chromosome missegregation and defects in cytoplasmic inheritance and the partitioning of organelles, which in turn are associated with human diseases. Although much is known about how chromosome segregation is coupled to cell division, the way organelles coordinate their inheritance during partitioning to daughter cells is less well understood. Here, using a high-content live-imaging small interfering RNA screen, we identify Myosin-XIX (Myo19) as a novel regulator of cell division. Previously, this actin-based motor was shown to control the interphase movement of mitochondria. Our analysis shows that Myo19 is indeed localized to mitochondria and that its silencing leads to defects in the distribution of mitochondria within cells and in mitochondrial partitioning at division. Furthermore, many Myo19 RNAi cells undergo stochastic division failure--a phenotype that can be mimicked using a treatment that blocks mitochondrial fission and rescued by decreasing mitochondrial fusion, implying that mitochondria can physically interfere with cytokinesis. Strikingly, using live imaging we also observe the inappropriate movement of mitochondria to the poles of spindles in cells depleted for Myo19 as they enter anaphase. Since this phenocopies the results of an acute loss of actin filaments in anaphase, these data support a model whereby the Myo19 actin-based motor helps to control mitochondrial movement to ensure their faithful segregation during division. The presence of DNA within mitochondria makes their inheritance an especially important aspect of symmetrical cell division. Show less

Familial combined hyperlipidaemia (FCH) is the most common genetic dyslipidaemia associated with coronary artery disease. Single nucleotide polymorphisms (SNPs) and haplotypes in the APOA1/C3/A4/A5 gene cluster are associated with FCH in Caucasians and with elevated triglycerides (TG) in various ethnic groups. We examined these associations with FCH in Hong Kong Chinese. Fifty-six Chinese FCH patients and 176 unrelated controls were studied. Thirteen SNPs in the APOA1/C3/A4/A5 cluster were genotyped. Four alleles in APOA5 were associated with FCH (P<0.001). The -1131T>C (rs662799) and -3A>G (rs651821) SNPs in APOA5 were in almost complete linkage disequilibrium (LD, r(2)=0.99), and their minor alleles were more frequent (P<0.001) in FCH than controls (0.60 vs. 0.24). The odds ratio (OR) for FCH was 6.2 (95% CI, 2.6-14.8) and 6.1 (2.6-14.6) per copy of -1131C and -3G, respectively, and 24.6 (8.4-72.0) and 24.4 (8.4-70.9) in -1131C and -3G homozygotes, respectively, as compared to wild-type homozygotes. The 1891T>C (rs2266788) SNP was in LD (r(2)=0.68) with -1131T>C and -3A>G, and the minor allele was more frequent in FCH than controls (0.42 vs. 0.19, P<0.001). The 553G>T (rs2075291) nonsynonymous variant was also associated with FCH (0.15 vs. 0.04, P=0.001) and, along with -3A>G (or -1131T>C) and 1891T>C, contributed to haplotypes predicting FCH. The two tightly linked SNPs, -1131T>C and -3A>G polymorphism were significantly associated with lipid traits in all subjects combined, with variant homozygous subjects having higher TG and LDL-C and lower HDL-C levels. Some common polymorphisms and haplotypes in APOA5 are closely associated with FCH in Hong Kong Chinese, and these differ from those found in Caucasians. Show less

Exercise induces a pleiotropic adaptive response in skeletal muscle, largely through peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α). PGC-1α enhances lipid oxidation and thereby provides energy for sustained muscle contraction. Its potential implication in promoting muscle refueling remains unresolved, however. Here, we investigated a possible role of elevated PGC-1α levels in skeletal muscle lipogenesis in vivo and the molecular mechanisms that underlie PGC-1α-mediated de novo lipogenesis. To this end, we studied transgenic mice with physiological overexpression of PGC-1α and human muscle biopsies pre- and post-exercise. We demonstrate that PGC-1α enhances lipogenesis in skeletal muscle through liver X receptor α-dependent activation of the fatty acid synthase (FAS) promoter and by increasing FAS activity. Using chromatin immunoprecipitation, we establish a direct interaction between PGC-1α and the liver X receptor-responsive element in the FAS promoter. Moreover, we show for the first time that increased glucose uptake and activation of the pentose phosphate pathway provide substrates for RNA synthesis and cofactors for de novo lipogenesis. Similarly, we observed increased lipogenesis and lipid levels in human muscle biopsies that were obtained post-exercise. Our findings suggest that PGC-1α coordinates lipogenesis, intramyocellular lipid accumulation, and substrate oxidation in exercised skeletal muscle in vivo. Show less

Patients with diabetic nephropathy (DN) have increased plasma fasting triglyceride (TG) levels, and most prospective studies report that elevated TG precedes DN. TG-rich lipoprotein particles might promote progression of DN. To test the hypothesis that elevated TG levels contribute to the development of DN, one may examine whether a polymorphism strongly associated with TG levels affects DN risk. The apolipoprotein A5 (apoA5) -1131T-->C polymorphism has a large effect on the TG level, and all three genotypes are relatively common in East Asians. Therefore, we sought to examine the association of this polymorphism with DN. We genotyped the apoA5 -1131T-->C polymorphism in a case-control study involving 367 Chinese Type 2 diabetes patients with DN and 382 without DN, as well as 198 subjects without diabetes. Mean fasting TG levels were higher in CC than in TT carriers by 41%, 54%, and 62% in each of the three subject groups, respectively. However, the genotype distributions did not differ between patients with and without nephropathy (P=.69). Therefore, these results weigh against the hypothesis that high fasting TG per se causes DN. The strong association between TG level and DN may be due to a factor that is usually closely linked to TG level but that is not affected by the apoA5 polymorphism. Show less

Gaucher's disease, a lysosomal storage disorder caused by mutations in the gene encoding glucocerebrosidase (GCD), is currently treated by enzyme replacement therapy using recombinant GCD (Cerezyme) expressed in Chinese hamster ovary (CHO) cells. As complex glycans in mammalian cells do not terminate in mannose residues, which are essential for the biological uptake of GCD via macrophage mannose receptors in human patients with Gaucher's disease, an in vitro glycan modification is required in order to expose the mannose residues on the glycans of Cerezyme. In this report, the production of a recombinant human GCD in a carrot cell suspension culture is described. The recombinant plant-derived GCD (prGCD) is targeted to the storage vacuoles, using a plant-specific C-terminal sorting signal. Notably, the recombinant human GCD expressed in the carrot cells naturally contains terminal mannose residues on its complex glycans, apparently as a result of the activity of a special vacuolar enzyme that modifies complex glycans. Hence, the plant-produced recombinant human GCD does not require exposure of mannose residues in vitro, which is a requirement for the production of Cerezyme. prGCD also displays a level of biological activity similar to that of Cerezyme produced in CHO cells, as well as a highly homologous high-resolution three-dimensional structure, determined by X-ray crystallography. A single-dose toxicity study with prGCD in mice demonstrated the absence of treatment-related adverse reactions or clinical findings, indicating the potential safety of prGCD. prGCD is currently undergoing clinical studies, and may offer a new and alternative therapeutic option for Gaucher's disease. Show less

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. In DN patients, triglyceride (TG) level is elevated and lipoprotein lipase (LPL) activity, which hydrolyzes TG, is decreased. The LPL S447X and apolipoprotein E (APOE) exon 4 polymorphisms affect TG levels, and the APOC3 -455T>C polymorphism affects LPL activity. Our aim was to examine the association of these polymorphisms with nephropathy in type 2 diabetes. We examined these polymorphisms in a case-control study of type 2 diabetic patients including 374 with DN and 392 without DN. LPL 447X-containing genotypes (447X+) were significantly decreased in DN patients [18.6 vs 25.6%, odds ratio (OR) = 0.66, p = 0.02], as were APOE epsilon3/epsilon3 genotypes (64.8 vs 73.1%, OR = 0.68, p = 0.01). In addition, combinations of genotypes [APOE epsilon3/epsilon3 and LPL 447X+ (OR = 0.56), APOC3 CC and LPL 447X+ (OR = 0.31), APOE epsilon3/epsilon3 and APOC3 CC (OR = 0.61] were protective for DN compared with the most common combination of the respective polymorphisms. Our findings suggest the importance of interactions among lipid genes in modulating the risk of DN. Show less

Failure to treat deep vein thrombosis (DVT) is associated with significant morbidity and mortality. Anticoagulation, although effective at preventing clot progression, is not able to prevent postthrombotic syndrome. Catheter-directed thrombolysis is a more aggressive alternative, with some small studies suggesting a better long-term outcome, but the associated risks are significant, and the treatment can require 2-3 days in a monitored setting. This report describes the power pulse technique, in which mechanical thrombectomy is combined with thrombolytic agents to maximize the effectiveness of the treatment and reduce the need for prolonged infusion and its associated risks. A 24-patient retrospective study showed complete thrombus removal (>90%) in 12 patients, substantial thrombus removal (50%-90%) in seven patients, and partial thrombus removal (<50%) in five patients. All 24 patients had resolution of presenting symptoms. Only two patients required blood transfusion, and one patient experienced temporary nephropathy. Show less

Triglyceride-rich lipoprotein particles may promote the progression of diabetic nephropathy. Patients with diabetic nephropathy have increased plasma triglycerides and reduced activity of hepatic lipase (HL), which hydrolyzes triglycerides. We hypothesized that the HL -514C-->T polymorphism, which reduces HL expression, and its interactions with polymorphisms in apolipoprotein (apo) E and apoC3 increase the risk of diabetic nephropathy. In a case-control study involving 374 Chinese type 2 diabetic patients with and 392 without diabetic nephropathy, we genotyped the HL -514C-->T, apoE exon 4, and apoC3 -482C-->T polymorphisms. HL -514T-containing genotypes (T+) were associated with diabetic nephropathy (OR = 1.7, P = 0.0009). Adjustment by multiple logistic regression for hypertension, triglycerides, sex, non-HDL cholesterol, BMI, smoking, and alcohol intake did not diminish the association (OR = 1.8, P = 0.003). The association between HL T+ genotypes and diabetic nephropathy appeared stronger in diabetic patients with apoC3 -482 non-TT genotypes (OR = 1.9, P = 0.003) or apoE epsilon2 or epsilon4 alleles (OR = 2.2, P = 0.005). Subjects with HL TT exhibited trends toward increased triglyceride and non-HDL cholesterol levels compared with CC carriers. HL T+ genotypes might increase the risk of developing diabetic nephropathy by slowing clearance of triglyceride-rich remnant lipoproteins. In concert with other risk factors (e.g., hyperglycemia), lipid abnormalities may damage the kidneys and endothelium, where reduced binding sites for lipases may precipitate a vicious cycle of dyslipidemia, proteinuria, and nephropathy. Show less

A new apolipoprotein gene, APOA5, was recently discovered near the APOA1/C3/A4 gene cluster. Transgenic mice overexpressing the homologous gene, apoa5, showed reduced plasma triglyceride levels, while knockout mice had greatly increased triglycerides, suggesting that human genetic variants affecting expression of the protein product, APOAV, might affect triglyceride levels. Polymorphisms in the APOA5 gene were indeed found to be associated with triglyceride levels in men, though not in women. We sought to confirm the association of the APOA5-1131T>C polymorphism with triglyceride levels in 167 Chinese men chosen for having either high (>/=1.7 mm, n = 82) or low (Show less

We have studied the interaction of a human tumor cell line, A253, derived from a submandibular gland carcinoma with a differentiation promoting reconstituted basement membrane extract, Matrigel. When cultured on plastic, these cells maintain a flat, cobblestone, epithelial morphology. On Matrigel, A253 cells initially form a honeycomb network of cords of cells which subsequently thickens. With time, these cords of cells become discontinuous and blunted, whereupon multilobular clusters of cells develop. These clusters possess a lumen with polarized, PAS(+) cells containing numerous desmosomes and an abundance of glycogen. Culture of the cells on laminin, the most abundant protein found in Matrigel, also induces this morphologic differentiation. Using synthetic laminin-derived peptides, the biologically active IKVAV-containing site of laminin was most active in attachment assays, as well as in inhibiting glandular-like morphogenesis when added to the media of cells cultured on Matrigel. Antibodies to the cell surface 67- and 32-kDa laminin binding proteins partially inhibited the glandular-like morphogenesis, suggesting that multiple interactions with laminin are likely required for the differentiation process. Our data demonstrate that A253 cells can undergo glandular-like morphogenesis on basement membrane and that laminin appears to be the major initiating factor. Show less