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Subarachnoid hemorrhage (SAH) is a serious neurological event associated with high morbidity and mortality. Computed tomography of the cerebrum (CTC) is the diagnostic method of choice, but in case of negative CTC but strong suspicion of SAH, lumbar puncture with spectrophotometric analysis of cerebrospinal fluid (CSF) for xanthochromia is performed. We wanted to examine the diagnostic properties of CSF spectrophotometry for xanthochromia testing. We performed a retrospective study of the diagnostic properties of CSF analysis for xanthochromia using spectrophotometry in the diagnosis of SAH. A total of 489 CSF samples were analyzed for xanthochromia, according to international guidelines, from 2009 until 2014 and for 411 of these the patient files were retrieved and examined for final clinical diagnosis and result of CTC. One patient with SAH did not have a positive spectrophotometry report and another patient with SAH had an equivocal report. In four patients did initial CTC not correctly identify SAH. For patients with a negative CTC within six hours of symptom onset spectrophotometry for xanthochromia in the CSF had a diagnostic sensitivity of 100% and a diagnostic specificity of 98.5%. The positive predictive value was 16.7% and the negative predictive value 100%. We conclude that spectrophotometry of CSF for xanthochromia is a sensitive and specific test for diagnosing SAH. However, it seems that an initial CTC identifies almost all patients with SAH. This suggests that in our and similar diagnostic settings, lumbar puncture and testing for xanthochromia might only be relevant in very few cases, if not obsolete.

Angiopoietin-like 4 (ANGPTL4) is an endogenous inhibitor of lipoprotein lipase that modulates lipid levels, coronary atherosclerosis risk, and nutrient partitioning. We hypothesize that loss of ANGPTL4 function might improve glucose homeostasis and decrease risk of type 2 diabetes (T2D). We investigate protein-altering variants in ANGPTL4 among 58,124 participants in the DiscovEHR human genetics study, with follow-up studies in 82,766 T2D cases and 498,761 controls. Carriers of p.E40K, a variant that abolishes ANGPTL4 ability to inhibit lipoprotein lipase, have lower odds of T2D (odds ratio 0.89, 95% confidence interval 0.85–0.92, p = 6.3 × 10−10), lower fasting glucose, and greater insulin sensitivity. Predicted loss-of-function variants are associated with lower odds of T2D among 32,015 cases and 84,006 controls (odds ratio 0.71, 95% confidence interval 0.49–0.99, p = 0.041). Functional studies in Angptl4-deficient mice confirm improved insulin sensitivity and glucose homeostasis. In conclusion, genetic inactivation of ANGPTL4 is associated with improved glucose homeostasis and reduced risk of T2D., Genetic variation in ANGPTL4 is associated with lipid traits. Here, the authors find that predicted loss-of-function variants in ANGPTL4 are associated with glucose homeostasis and reduced risk of type 2 diabetes and that Angptl4−/− mice on a high-fat diet show improved insulin sensitivity.

Objective— Loss-of-function mutations in APOC3 associate with low remnant cholesterol levels and low risk of ischemic vascular disease (IVD). Because some studies show an additional association with low levels of low-density lipoprotein cholesterol (LDL-C), low LDL-C may explain the low risk of IVD in APOC3 loss-of-function heterozygotes. We tested to what extent the low risk of IVD in APOC3 loss-of-function heterozygotes is mediated by low plasma remnant cholesterol and LDL-C. Approach and Results— In APOC3 loss-of-function heterozygotes versus noncarriers, we first determined remnant cholesterol and LDL-C levels in meta-analyses of 137 895 individuals. Second, we determined whether the association with LDL-C was masked by lipid-lowering therapy. Finally, using mediation analysis, we determined the fraction of the low risk of IVD and ischemic heart disease mediated by remnant cholesterol and LDL-C. In meta-analyses, remnant cholesterol was 43% lower (95% confidence interval, 40%–47%), and LDL-C was 4% lower (1%–6%) in loss-of-function heterozygotes (n=776) versus noncarriers. In the general population, LDL-C was 3% lower in loss-of-function heterozygotes versus noncarriers, 4% lower when correcting for lipid-lowering therapy, and 3% lower in untreated individuals ( P values, 0.06–0.008). Remnant cholesterol mediated 37% of the observed 41% lower risk of IVD and 54% of the observed 36% lower risk of ischemic heart disease; corresponding values mediated by LDL-C were 1% and 2%. Conclusions— The low risk of IVD observed in APOC3 loss-of-function heterozygotes is mainly mediated by the associated low remnant cholesterol and not by low LDL-C. Furthermore, the contribution of LDL-C to IVD risk was not masked by lipid-lowering therapy. This suggests APOC3 and remnant cholesterol as important new targets for reducing cardiovascular risk.

BackgroundLoss-of-function variants in the angiopoietin-like 3 gene (ANGPTL3) have been associated with decreased plasma levels of triglycerides, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol. It is not known whether such variants or therapeutic antagonism of ANGPTL3 are associated with a reduced risk of atherosclerotic cardiovascular disease. MethodsWe sequenced the exons of ANGPTL3 in 58,335 participants in the DiscovEHR human genetics study. We performed tests of association for loss-of-function variants in ANGPTL3 with lipid levels and with coronary artery disease in 13,102 case patients and 40,430 controls from the DiscovEHR study, with follow-up studies involving 23,317 case patients and 107,166 controls from four population studies. We also tested the effects of a human monoclonal antibody, evinacumab, against Angptl3 in dyslipidemic mice and against ANGPTL3 in healthy human volunteers with elevated levels of triglycerides or LDL cholesterol. ResultsIn th...