Effects of a moderate‐intensity static magnetic field on VEGF‐A stimulated endothelial capillary tubule formation in vitro

Abstract

Effects of a moderate-intensity static magnetic field (SMF) on the early-stage development of endothelial capillary tubule formation were examined during the initial cell growth periods using co-cultured human umbilical vein endothelial cells and human diploid fibroblasts. The co-cultured cells within a well (16 mm in diameter) were exposed to SMF intensity up to 120 mT (Bmax) with the maximum spatial gradient of 21 mT/mm using a disc-shaped permanent magnet (16 mm in diameter and 2.5 mm in height) for up to 10 days. Control exposure was performed without magnet. Some vascular endothelial cells were treated with vascular endothelial growth factor (VEGF)-A (10 ng/ml) to promote the tubule formation every 2-3 days. Four experimental protocols were performed: (1) non-exposure (control); (2) SMF exposure alone; (3) non-exposure with VEGF-A; (4) SMF exposure with VEGF-A. Photomicrographs of tubule cells immunostained with an anti-platelet-endothelial cell adhesion molecule-1 (PECAM-1 [CD31[) antibody as a pan-endothelial marker, were analyzed after culture at 37 degrees C for 4, 7, and 10 days. The mean values of the area density and the length of tubules (related mainly to arteriogenesis) as well as the number of bifurcations (related mainly to angiogenesis) were determined as parameters of tubule formation and were compared between the groups. After a 10 day incubation, in the peripheral part of the culture wells, SMF alone significantly promoted the tubule formation in terms of the area density and the length of tubules, compared with control group. In the central part of the wells, however, SMF did not cause any significant changes in the parameters of tubule formation. After a 7 day incubation, VEGF-A significantly promoted all the parameters of tubule formation in any part of the wells, compared with control group. With regard to the synergistic effects of SMF and VEGF-A on tubule formation, after a 10 day incubation, SMF significantly promoted the VEGF-A-increased area density and length of tubules in the peripheral part of the wells, compared with the VEGF-A treatment alone. However, SMF did not induce any significant changes in the VEGF-A-increased number of bifurcations in any part of the wells. The tubule cells observed in the wells had elongated, spindle-like shapes, and the direction of cell elongation was random, irrespective of the presence and direction of SMF. These findings suggest that the application of SMF to intact or VEGF-A-stimulated vascular endothelial cells leads mainly to promote or enhance arteriogenesis in the peripheral part of the wells, where the spatial gradient increases relative to the central part. The effects of SMF on the VEGF-A-enhanced tubule formation appear to be synergistic or additive in arteriogenesis but not in angiogenesis.

Influence of Donor Age and Passage Number on Angiogenic Activity in Human Adipose-Derived Stem Cell-Conditioned Media

“…To our knowledge, this is the first study reporting a passage number-dependent but donor age-independent decline in angiogenic activity in ASC-CM. VEGF-A [34], HGF [36], and FGF-2 [35] stimulate the formation of tube-like structures in this assay system. As shown in Fig.…”

“…Previous studies demonstrated that angiogenic factors such as VEGF-A [34], FGF-2 [35], and HGF [36] promote HUVEC tube formation. We next evaluated the concentration of these angiogenic factors in ASC-CM using ELISA.…”

Reduction VEGF-A expression induced by saffron aqua extract with low frequency electromagnetic field in MCF-7 cell line

“…Furthermore effects of moderate-intensity static magnetic field (SMF) on the VEGF-A-enhanced tubule formation investigated by Okano in 2006 reveals that SMF seems to be synergistic or additive in arteriogenesis but not in angiogenesis and it significantly promoted the VEGF-A-increased area density and length of tubules in the peripheral part of the wells, compared with the VEGF-A treatment alone. However, SMF did not induce any significant changes in the VEGF-A-increased number of bifurcations in any part of the wells [25]. Additionally it is reported that Pulsed electromagnetic fields (PEMF) had ability to increase in vitro and in vivo angiogenesis through endothelial release of FGF-2 and inducing paracrine and autocrine changes in the surrounding tissues [26].…”

Short-Term Effects of Extremely Low Frequency Pulsed Electromagnetic Field on Corneas with Alkaline Burns in Rabbits

“…Pulsed electromagnetic fields were shown to induce vascular endothelial cell growth and angiogenesis through influencing the vascular endothelial growth factor (VEGF)-related pathways. 24,25 In another study, Yuan et al 26 reported induced angiogenesis and the improvement of cardiac function in a surgically-induced infarcted myocardium, after implementing a pulsed magnetic field. In this current study, although in both clinical and histopathologic investigations, there was not a remarkable difference in the rate of stromal neovascularization between the groups; the progression rate of neovascularization over a 2-week period was statistically significant in the magnetic therapy groups and was comparable with the control; such a progression, however, was not observed in the MT group; this was probably due to use of corticosteroids.…”