Objective: Netrin-1 has been shown to play a role in the initiation of atherosclerosis in mice models. However, little is known about the role of Netrin-1 in humans. We set out to study whether Netrin-1 is associated with different stages of atherosclerosis. Approach and Results: Plasma Netrin-1 levels were measured in different patient cohorts: (1) 22 patients with high cardiovascular risk who underwent arterial wall inflammation assessment using positron-emission tomography / computed tomography, (2) 168 patients with a positive family history of premature atherosclerosis in whom coronary artery calcium scores were obtained, and (3) 104 patients with chest pain who underwent coronary computed tomography angiography imaging to evaluate plaque vulnerability and burden. Netrin-1 plasma levels were negatively correlated with arterial wall inflammation (β, −0.01 [95% CI, 0.02 to −0.01] R 2 , 0.61; P <0.0001), and concentrations of Netrin-1 were significantly lower when atherosclerosis was present compared with individuals without atherosclerosis (28.01 versus 10.51 ng/mL, P <0.001). There was no difference in Netrin-1 plasma concentrations between patients with stable versus unstable plaques (11.17 versus 11.74 ng/mL, P =0.511). However, Netrin-1 plasma levels were negatively correlated to total plaque volume (β, −0.09 [95% CI, −0.11 to −0.08] R 2 , 0.57, P <0.0001), calcified plaque volumes (β, −0.10 [95% CI, −0.12 to −0.08] R 2 , 0.53; P <0.0001), and noncalcified plaque volumes (β, −0.08 [95% CI, −0.10 to −0.06] R 2 , 0.41; P <0.0001). Treatment of inflammatory stimulated endothelial cells with plasma with high Netrin-1 level resulted in reduced endothelial inflammation and consequently, less monocyte adhesion. ConclusionS: Netrin-1 plasma levels are lower in patients with subclinical atherosclerosis and in patients with arterial wall inflammation. Netrin-1 is not associated with plaque vulnerability; however, it is negatively correlated to plaque burden, suggesting that Netrin-1 is involved in some, but not all, stages of atherosclerosis.

Netrins form a family of secreted and membrane-associated proteins. Netrins are involved in processes for axonal guidance, morphogenesis, and angiogenesis by regulating cell migration and survival. These processes are of special interest in tumor biology. From the netrin genes various isoforms are translated and regulated by alternative splicing. We review here the diversity of isoforms of the netrin family members and their known and potential roles in cancer.

The phenotype of familial hypercholesterolemia is caused by more than 1700 mutations the LDLR, apoB and PCSK9 genes, which explains approximately 85% of familial hypercholesterolemia cases. By means of next-generation sequencing, an increasing number of mutations in established and putative novel genes associated with this phenotype have been identified.