Angiogenesis and angiogenesis inhibitors in paediatric diseases

Adult neck hemangiolymphangioma: a case and review of its etiology, diagnosis and management

Vascular anomalies constitute some of the most difficult diagnostic and therapeutic enigmas in the practice of medicine, ranging from an asymptomatic birthmark to life-threatening congestive heart failure. Hemangiolymphangiomas (HLA) are extremely rare vascular malformations of both lymphatic and blood vessels in which 80-90% are diagnosed during the first 2 years of life. Though rare, these vascular malformations have promising clinical outcomes. We report a case of a 28-year-old male who presented with a neck mass of unknown etiology. A computed axial tomography scan revealed a cystic mass, and subsequent aspiration biopsy showed lymphatic fluid. The mass was surgically excised and identified as a 6 × 6 × 3 cm³ multilocular cystic mass weighing 81 g. Histopathology showed cellular characteristics consistent with HLA. We review the salient clinical and pathophysiologic features of vascular anomalies.

Blood and lymph vessels in embryonic tumors

Formation of embryonic blood and lymph vessels is mediated by different steps of vasculogenesis and angiogenesis. The vascular endothelial growth factor family (VEGF) as well as the VEGF-receptors on the surface of blood endothelial cells and lymph endothelial cells are responsible for both processes. In addition to the embryonic development of the vessel systems, the interactions of angiogenesis factors and receptors are also present in solid tumors. Embryonic tumors in children offer an interesting target for new substances developed for anti-angiogenesis. Some data on the role of blood vessels and anti-blood-angiogenesis are available on embryonic tumors. However, studies of lymph-angiogenesis are not found and anti-lymph-angiogenesis is not at all examined in embryonic tumors. This review gives an overview of the challenging field of angiogenesis and anti-angiogenesis of both blood and lymph vessels with a focus on embryonic tumors.

The clinical manipulation of angiogenesis: pathology, side-effects, surprises, and opportunities with novel human therapies

The first phase of angiogenesis research has provided knowledge of the basic pathobiology of angiogenesis and its manipulation in models, mouse, and man. The first line of therapeutic substances has been devised and is now in clinical trials. New lessons are being learned from clinical observations. Unexpected side-effects are being noted, particularly affecting the nervous system. Other side-effects may be anticipated from a sound knowledge of clinical pathology and recognition of the commonality of angiogenesis to multiple disease mechanisms, but these may be tolerable or avoidable. Angiogenesis researchers await further feedback and ideas from the clinic to stimulate the next phase of basic and applied research.

The role of the vascular phase in solid tumor growth: a historical review

Angiogenesis is a biological process by which new capillaries are formed from pre-existing vessels. It occurs in both physiological conditions such as embryo development, cyclically in the female genital system and during wound repair, and pathological conditions, such as arthritis, diabetic retinopathy and tumors. In solid tumor growth, a specific critical turning point is the transition from the avascular to the vascular phase. Having developed an intrinsic vascular network, the neoplastic mass is able to grow indefinitely (unlike all the other forms, tumor angiogenesis is not limited in time) both in situ and at distant sites (metastasis) in so far as an intrinsic vascular network enables its cells to enter the vascular bed and colonize other organs. Tumor angiogenesis depends mainly on the release by neoplastic cells of growth factors specific for endothelial cells and able to stimulate growth of the host's blood vessels. This review describes its history as traced by the main contributions to the international medical literature and their contents. The specific new paradigm discussed here has been gaining general approval and considerable confirmation, thanks to its possible applications, as recently highlighted by the introduction of anti-angiogenic substances in adjuvant tumor management.

The clinical manipulation of angiogenesis: pathology, side-effects, surprises, and opportunities with novel human therapies

The first phase of angiogenesis research has provided knowledge of the basic pathobiology of angiogenesis and its manipulation in models, mouse, and man. The first line of therapeutic substances has been devised and is now in clinical trials. New lessons are being learned from clinical observations. Unexpected side-effects are being noted, particularly affecting the nervous system. Other side-effects may be anticipated from a sound knowledge of clinical pathology and recognition of the commonality of angiogenesis to multiple disease mechanisms, but these may be tolerable or avoidable. Angiogenesis researchers await further feedback and ideas from the clinic to stimulate the next phase of basic and applied research.

Angiogenesis inhibition: a review

In this review we discuss the concept of anti-angiogenesis, which is the inhibition of neovascularization. Anti-angiogenic agents are viewed from the standpoint of their effect on various elements of the angiogenic process, including induction of vascular discontinuity, endothelial cell movement, endothelial cell proliferation, and three-dimensional restructuring of patent vessels. An effort is made to place the many different approaches to anti-angiogenesis research into a comprehensible structure, in order to identify problems of evaluation and interpretation, thereby providing a clearer basis for determining promising and needed directions for further investigation.

Genistein, a dietary-derived inhibitor of in vitro angiogenesis

Consumption of a plant-based diet can prevent the development and progression of chronic diseases that are associated with extensive neovascularization; however, little is known about the mechanisms. To determine whether prevention might be associated with dietary-derived angiogenesis inhibitors, we have fractionated urine of healthy human subjects consuming a plant-based diet and examined the fractions for their abilities to inhibit the proliferation of vascular endothelial cells. Using gas chromatography-mass spectrometry, we showed that one of the most potent fractions contained several isoflavonoids, which we subsequently synthesized. Of all synthetic compounds, the isoflavonoid genistein was the most potent and inhibited endothelial cell proliferation and in vitro angiogenesis at concentrations giving half-maximal inhibition of 5 and 150 microM, respectively. As we have previously demonstrated, genistein concentrations in urine of subjects consuming a plant-based diet are in the micromolar range, while those of subjects consuming a traditional Western diet are lower by a factor of > 30. The high excretion of genistein in urine of vegetarians and our present results suggest that genistein may contribute to the preventive effect of a plant-based diet on chronic diseases, including solid tumors, by inhibiting neovascularization. Thus, genistein may represent a member of a new class of dietary-derived anti-angiogenic compounds.