Investigating mechanisms of angiogenesis in health and disease using zebrafish models

Abstract

Angiogenesis, the growth of blood vessels from an existing vasculature, can occur by sprouting from preexisting vessels or by vessel splitting (intussusception). Pathological angiogenesis drives choroidal neovascularization (CNV) in age related macular degeneration (AMD) which is commonly restricted under the retinal pigment epithelium (RPE), called occult CNV, but may also involve vessels penetrating through the RPE into the sub-retinal space. Pathological vessels are poorly developed, insufficiently perfused and highly leaky, phenotypes that are considered to drive disease progression and lead to poor prognosis. Currently, a number of anti-angiogenic drugs exists, the majority of which target vascular endothelial factor (VEGF), but although they often are highly beneficial for treating eye diseases in the short-term, they are generally of limited efficacy in other diseases such as cancer, and also have poorer efficacy when used for treatment of eye diseases in the long-term. A better understanding of the mechanisms underlying pathological angiogenesis can generate new targets for treatment leading to development of better drugs for cancer and retinopathies, but perhaps also other angiogenesis-dependent diseases, in the future. In this thesis mechanisms involved in developmental angiogenesis or pathological angiogenesis in the choroid, cornea or melanoma was identified. These findings highlight the need to further elaborate our knowledge related to angiogenesis in different tissues/conditions for a more targeted, and potentially effective treatment of diseases in the future.

Enhanced NK cell proliferation by stress-induced feeder cells

“…HIF-1α accumulates within cells under hypoxic conditions, is known to regulate the p27 expression, thereby preventing cells in the G1 phase from entering the S phase [23]. However, under normoxic conditions, the accumulated HIF-1α is decomposed, allowing the cell cycle to proceed normally again [24]. Therefore, the decrease in cell density and expression of proliferation-related markers in the hypoxia-only treatment group was less pronounced than in the other groups.…”