👤 C M A Reijnders

Residual cardiovascular risk remains, despite achieving low-density lipoprotein cholesterol targets with high-intensity statins. Traditional risk scores are suboptimal. This study evaluated the prognostic utility of a 9-plex apolipoprotein panel in recent patients with acute coronary syndrome on statins and its role in predicting treatment benefit by alirocumab, a PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor, enabling precision medicine. Baseline serum samples from 11 843 participants in the ODYSSEY OUTCOMES trial (https://www.clinicaltrials.gov; Unique identifier: NCT01663402) were analyzed using mass spectrometry to measure Apo(a), ApoA-I, ApoA-II, ApoA-IV, ApoB, ApoC-I, ApoC-II, ApoC-III, and ApoE. Using logistic regression, probabilities of major adverse cardiovascular events (MACE) and all-cause death over a median follow-up of 2.9 years were estimated based on baseline apolipoproteins and lipid concentrations. Clinical performance was assessed by comparing the area under the curve (AUC) of 3 models: the apolipoprotein panel, the lipid panel (total cholesterol, high-density lipoprotein cholesterol, and triglycerides), and a combination. In addition, prediction models estimating the treatment benefit of alirocumab by the apolipoprotein panel were developed. The prognostic performance of the apolipoprotein panel for MACE showed an AUC (95% CI) of 0.648 (0.626-0.670), compared with 0.579 (0.557-0.602) for the lipid panel. For all-cause death, the apolipoprotein panel had an AUC of 0.699 (0.664-0.733), while the lipid panel had an AUC of 0.599 (0.564-0.635). Adding the apolipoprotein panel significantly improved the performance of the conventional lipid panel ( A multiplex apolipoprotein panel led to better prediction of MACE and all-cause death, beyond lipids, in patients with postacute coronary syndrome on optimized statin therapy. The panel also predicts the treatment benefit of alirocumab. Further validation of this approach is now needed, and if confirmed and improved, it could lead to better disease prediction and management in the future. Show less

Apolipoprotein (Apo) C3 has been associated with incident coronary heart disease and major adverse cardiovascular events (MACE). Whether ApoC3 levels predict risk in patients with acute coronary syndrome (ACS) on optimized statin treatment is unknown. ApoC3 was measured by mass spectrometry at baseline (n=11,956) and after 4 months' treatment (M4; n=11 176) with alirocumab or placebo in the ODYSSEY OUTCOMES trial. Patients with fasting triglycerides >400 mg/dL were excluded. The association of baseline ApoC3 with risk of MACE or death was assessed in post hoc adjusted Cox regression models and spline analyses adjusted for treatment and ApoB. In adjusted models in the alirocumab group we determined association of ApoC3 change from baseline to M4 with subsequent risk of MACE and death. Median (Q1, Q3) baseline ApoC3 concentration was 85 (65, 113) mg/L. With adjustment for ApoB, baseline ApoC3 showed no clinically meaningful relationship to risk of MACE or death in spline analyses and no association with MACE (P=0.89) or death (P=0.70) in Cox regression analyses. Alirocumab reduced ApoC3 modestly by median -10 (-27, -5) mg/L (P<0.0001) and reduced MACE (10.1% vs 12.1%; P=0.0006) and death (3.5% vs 4.2%; P=0.045) versus placebo. However, the change in ApoC3 on alirocumab did not predict subsequent MACE or death. In patients with recent ACS on optimized statins without severe hypertriglyceridemia, neither baseline ApoC3 (accounting for ApoB) nor ApoC3 change with alirocumab predicted MACE or death. It is uncertain whether targeted therapies producing larger reductions in ApoC3 from higher baseline levels will affect cardiovascular risk. Show less

Multiple osteochondromas (MO) is a syndrome in which benign cartilage-capped neoplasms develop at the surface of the long bones. Most cases are caused by exonic changes in EXT1 or EXT2, but 15% are negative for these changes. Here we report for the first time a family of MO patients with germline genomic alterations at the EXT1 locus without detectable mutations or copy number alterations of EXT exonic sequences. Array-CGH showed an 80.7 kb deletion of Intron 1 of EXT1 and a 68.9 kb duplication proximal of EXT1. We identified a breakpoint between the distal end of the duplicated region and a sequence distal of the deleted region in the first intron. This breakpoint was absent in non-affected family members. The configuration of the breakpoint indicates a direct insertion of the duplicated region into the deletion. However, no other breakpoint was found, which suggests a more complex genomic rearrangement has occurred within the duplicated region. Our results reveal intronic deletion and duplication as a new causative mechanism for MO not detected by conventional diagnostic methods. Show less

Secondary peripheral chondrosarcoma is the result of malignant transformation of a pre-existing osteochondroma, the most common benign bone tumor. Osteochondromas are caused by genetic abnormalities in EXT1 or EXT2: homozygous deletion of EXT1 characterizes sporadic osteochondromas (non-familial/solitary), and germline mutations in EXT1 or EXT2 combined with loss of heterozygosity define hereditary multiple osteochondromas. While cells with homozygous inactivation of EXT and wild-type cells shape osteochondromas, the cellular composition of secondary peripheral chondrosarcomas and the role of EXT in their formation have remained unclear. We report using a targeted-tiling-resolution oligo-array-CGH (array comparative genomic hybridization) that homozygous deletions of EXT1 or EXT2 are much less frequently detected (2/17, 12%) in sporadic secondary peripheral chondrosarcomas than expected based on the assumption that they originate in sporadic osteochondromas, in which homozygous inactivation of EXT1 is found in ~80% of our cases. FISH with an EXT1 probe confirmed that, unlike sporadic osteochondromas, cells from sporadic secondary peripheral chondrosarcomas predominantly retained one (hemizygous deleted loci) or both copies (wild-type) of the EXT1 locus. By immunohistochemistry, we confirm the presence of cells with dysfunctional EXT1 in sporadic osteochondromas and show cells with functional EXT1 in sporadic secondary peripheral chondrosarcomas. These immuno results were verified in osteochondromas and secondary peripheral chondrosarcomas in the setting of hereditary multiple osteochondromas. Our data therefore point to a model of oncogenesis in which the osteochondroma creates a niche in which wild-type cells with functional EXT are predisposed to acquire other mutations giving rise to secondary peripheral chondrosarcoma, indicating that EXT-independent mechanisms are involved in the pathogenesis of secondary peripheral chondrosarcoma. Show less

Multiple osteochondromas (MO) is an autosomal dominant disorder caused by germline mutations in EXT1 and/or EXT2. In contrast, solitary osteochondroma (SO) is nonhereditary. Products of the EXT gene are involved in heparan sulfate (HS) biosynthesis. In this study, we investigated whether osteochondromas arise via either loss of heterozygosity (2 hits) or haploinsufficiency. An in vitro three-dimensional chondrogenic pellet model was used to compare heterozygous bone marrow-derived mesenchymal stem cells (MSCs EXT(wt/-)) of MO patients with normal MSCs and the corresponding tumor specimens (presumed EXT(-/-)). We demonstrated a second hit in EXT in five of eight osteochondromas. HS chain length and structure, in vitro chondrogenesis, and EXT expression levels were identical in both EXT(wt/-) and normal MSCs. Immunohistochemistry for HS, HS proteoglycans, and HS-dependent signaling pathways (eg, TGF-β/BMP, Wnt, and PTHLH) also showed no differences. The cartilaginous cap of osteochondroma contained a mixture of HS-positive and HS-negative cells. Because a heterozygous EXT mutation does not affect chondrogenesis, EXT, HS, or downstream signaling pathways in MSCs, our results refute the haploinsufficiency theory. We found a second hit in 63% of analyzed osteochondromas, supporting the hypothesis that osteochondromas arise via loss of heterozygosity. The detection of the second hit may depend on the ratio of HS-positive (normal) versus HS-negative (mutated) cells in the cartilaginous cap of the osteochondroma. Show less