To verify the possible role played by pig granulosa cells in the ovarian angiogenic process, we have developed a reliable in vitro system which allows the evaluation of endothelial sprouting and capillary growth in three-dimensional matrices. Granulosa cells collected from porcine follicles of different size were co-cultured with porcine aortic endothelial cells (PAEC) in a microcarrier-based fibrin gel system; after 2 and 5 days of co-culture, we determined the number and length of all endothelial sprouts; moreover, these parameters were quantified only in capillary-like structures, which were defined as continuous multicellular sprouts at least 200 µm long. In granulosa cells- PAEC co-cultures we observed an increase of angiogenic activity as compared to controls (PAEC alone). Granulosa cells from follicles of different size regulate angiogenesis differently: cells from the small follicle group significantly enhanced endothelial sprouting, while those from the large follicle group favoured mainly capillary elongation. Our observations seem therefore to suggest that the development and growth of thecal vascular bed is controlled by paracrine factors of granulosa cell origin that may induce the formation of a primitive capillary plexus during the early phases of antral follicle growth, which will be remodelled in more advanced phases of follicular development.
It is increasingly recognized that obstructive sleep apnea (OSA) syndrome is a systematic rather than local disorder. There is also growing evidence that apart from the syndrome's major features: intermittent hypoxia and sleep fragmentation, functional activity of the immune system is altered in OSA patients, with several cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) taking active part in sleep regulation. Little is known about the effects exerted by chronic intermittent hypoxia combined with persistent pro-inflammatory activity of the immune system on the vascular micro milieu in OSA. In this study we attempted to confirm the hypothesized imbalance between pro- and anti-angiogenic factors by evaluating direct and indirect angiogenic activity of OSA patients' sera in the in vivo serum-induced angiogenesis (SIA) and leukocyte-induced (LIA) assays, respectively, in mice. Both tests revealed significantly inhibited angiogenic activity of OSA patients' sera compared with healthy controls (P<0.001). Moreover, differences related to the subject’s weight regarding in the mean number of newly-formed vessels were observed with a significantly greater inhibition in the normal-weighing apneic subjects than in the overweight or obese ones (P<0.01). The angiogenesis inhibition index was positively related to the serum IL-6 level (r=0.35; P<0.05) in the OSA group, but not to TNF-alpha, fasting serum leptin, or OSA syndrome severity as assessed by the AHI index. Our results demonstrate that OSA is accompanied by disturbed serum angiogenic activity, apparently resulting from an imbalance between pro- and anti-angiogenic factors, some of them being produced by the adipose tissue. The disordered angiogenic activity might be related to the pathophysiology of OSA and should be considered an important causative factor for the increased prevalence of cardiovascular diseases in OSA patients.
Numerous bioactive chemical compounds of plant origin may influence the angiogenic activity of various cell types and may thus affect the formation of blood vessels. Here we present the angiogenic effects of extracts of edible plants collected in Crete, Southern Italy and Southern Spain. Extracts have been applied to cultured human microvascular endothelial cells (HMEC-1), human umbilical vein endothelial cells (HUVEC) and human keratinocytes (HaCaT). About half out of 96 extracts exerted an inhibitory effect on HMEC-1 proliferation. Additionally, we have noted the inhibitory effects of extracts on HUVEC differentiation on a Matrigel layer. None of the extracts showed a stimulatory activity. The extract of Thymus piperella exerted moderate inhibitory effect on cobalt-chloride induced VEGF synthesis, however, CoCl2-induced activation of hypoxia responsive element of VEGF promoter was significantly attenuated only by extract of Origanum heracleoticum. Our study indicates that extracts of local food plants, of potential value as nutraceuticals, contain chemical compounds which may inhibit angiogenesis. Demonstration of their real influence on human health requires, however, extensive animal studies and controlled clinical investigations.
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