Adventitial lymphatic capillary expansion impacts on plaque T cell accumulation in atherosclerosis

During plaque progression, inflammatory cells progressively accumulate in the adventitia, paralleled by an increased presence of leaky vasa vasorum. We here show that next to vasa vasorum, also the adventitial lymphatic capillary bed is expanding during plaque development in humans and mouse models of atherosclerosis. Furthermore, we investigated the role of lymphatics in atherosclerosis progression. Dissection of plaque draining lymph node and lymphatic vessel in atherosclerotic ApoE(-/-)mice aggravated plaque formation, which was accompanied by increased intimal and adventitial CD3(+) T cell numbers. Likewise, inhibition of VEGF-C/D dependent lymphangiogenesis by AAV aided gene transfer of hVEGFR3-Ig fusion protein resulted in CD3(+) T cell enrichment in plaque intima and adventitia. hVEGFR3-Ig gene transfer did not compromise adventitial lymphatic density, pointing to VEGF-C/D independent lymphangiogenesis. We were able to identify the CXCL12/CXCR4 axis, which has previously been shown to indirectly activate VEGFR3, as a likely pathway, in that its focal silencing attenuated lymphangiogenesis and augmented T cell presence. Taken together, our study not only shows profound, partly CXCL12/CXCR4 mediated, expansion of lymph capillaries in the adventitia of atherosclerotic plaque in humans and mice, but also is the first to attribute an important role of lymphatics in plaque T cell accumulation and development.Peer reviewe

Insights From Liver-Humanized Mice on Cholesterol Lipoprotein Metabolism and LXR-Agonist Pharmacodynamics in Humans

Background and Aims Genetically modified mice have been used extensively to study human disease. However, the data gained are not always translatable to humans because of major species differences. Liver-humanized mice (LHM) are considered a promising model to study human hepatic and systemic metabolism. Therefore, we aimed to further explore their lipoprotein metabolism and to characterize key hepatic species-related, physiological differences. Approach and Results Fah(-/-), Rag2(-/-), and Il2rg(-/-) knockout mice on the nonobese diabetic (FRGN) background were repopulated with primary human hepatocytes from different donors. Cholesterol lipoprotein profiles of LHM showed a human-like pattern, characterized by a high ratio of low-density lipoprotein to high-density lipoprotein, and dependency on the human donor. This pattern was determined by a higher level of apolipoprotein B100 in circulation, as a result of lower hepatic mRNA editing and low-density lipoprotein receptor expression, and higher levels of circulating proprotein convertase subtilisin/kexin type 9. As a consequence, LHM lipoproteins bind to human aortic proteoglycans in a pattern similar to human lipoproteins. Unexpectedly, cholesteryl ester transfer protein was not required to determine the human-like cholesterol lipoprotein profile. Moreover, LHM treated with GW3965 mimicked the negative lipid outcomes of the first human trial of liver X receptor stimulation (i.e., a dramatic increase of cholesterol and triglycerides in circulation). Innovatively, LHM allowed the characterization of these effects at a molecular level. Conclusions LHM represent an interesting translatable model of human hepatic and lipoprotein metabolism. Because several metabolic parameters displayed donor dependency, LHM may also be used in studies for personalized medicine.Peer reviewe

VEGFR-3 controls tip to stalk conversion at vessel fusion sites by reinforcing Notch signalling

Angiogenesis, the growth of new blood vessels, involves specification of endothelial cells to tip cells and stalk cells, which is controlled by Notch signalling, whereas vascular endothelial growth factor receptor (VEGFR)-2 and VEGFR-3 have been implicated in angiogenic sprouting. Surprisingly, we found that endothelial deletion of Vegfr3, but not VEGFR-3-blocking antibodies, postnatally led to excessive angiogenic sprouting and branching, and decreased the level of Notch signalling, indicating that VEGFR-3 possesses passive and active signalling modalities. Furthermore, macrophages expressing the VEGFR-3 and VEGFR-2 ligand VEGF-C localized to vessel branch points, and Vegfc heterozygous mice exhibited inefficient angiogenesis characterized by decreased vascular branching. FoxC2 is a known regulator of Notch ligand and target gene expression, and Foxc2(+/-);Vegfr3(+/-) compound heterozygosity recapitulated homozygous loss of Vegfr3. These results indicate that macrophage-derived VEGF-C activates VEGFR-3 in tip cells to reinforce Notch signalling, which contributes to the phenotypic conversion of endothelial cells at fusion points of vessel sprouts

A new perspective on adolescent athletes’ transition into upper secondary school : A longitudinal mixed methods study protocol

The challenge of combining elite sport and education into a dual career pathway remains to be a source of concern for many high-performance athletes. Previous research findings suggest that committed participation in both domains is highly demanding and success in one pursuit often comes at the expense of the other. There are emergent studies, however, that argue for the beneficial and complementary nature of dual career pathways. Consequently, we emphasize the importance of understanding the processes underlying differences in the development of athletes’ life trajectories. This article presents a study protocol to explore new methodological and analytical approaches that may extend current understandings of the ways psychological and sociocultural processes are interconnected in the construction of adolescent athletes’ identities, motivation, well-being, and career aspirations in the transitory social world.peerReviewe

Cold Weather and Cardiac Arrest in 4 Seasons: Helsinki, Finland, 1997‒2018

Objectives. To test the a priori hypothesis that out-of-hospital cardiac arrest (OHCA) is associated with cold weather during all seasons, not only during the winter. Methods. We applied a case–crossover design to all cases of nontraumatic OHCA in Helsinki, Finland, over 22 years: 1997 to 2018. We statistically defined cold weather for each case and season, and applied conditional logistic regression with 2 complementary models a priori according to the season of death. Results. There was an association between cold weather and OHCA during all seasons, not only during the winter. Each additional cold day increased the odds of OHCA by 7% (95% confidence interval [CI] 5 4%, 10%), with similar strength of association during the autumn (6%; 95% CI 5 0%, 12%), winter (6%; 95% CI 5 1%, 12%), spring (8%; 95% CI 5 2%, 14%), and summer (7%; 95% CI 5 0%, 15%). Conclusions. Cold weather, defined according to season, increased the odds of OHCA during all seasons in similar quantity. Public Health Implications. Early warning systems and cold weather plans focus implicitly on the winter season. This may lead to incomplete measures in reducing excess mortality related to cold weather