Expression of VEGF and collagen using a latex biomembrane as bladder replacement in rabbits

Abstract

ARTIcLE INFO _________________________________________________________ ___________________Objective: To investigate the VEGF expression and collagen deposition using a latex biomembrane as bladder replacement in rabbits. Materials and Methods: After partial cystectomy, a patch of a non-vulcanized latex biomembrane (2 x 2 cm) was sewn to the bladder of rabbits with 5/0 monofilament polydioxanone sulfate sutures in a watertight manner. Groups of 5 animals were killed at 15, 45 and 90 days after surgery and the bladder was removed. Sections of 5µm were cut and stained with picrosirius-red in order to estimate the amount of extracellular matrix in the graft. To confirm the presence of VEGF in tissues, protein expression was determined by immunohistochemistry. Results: No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. A progressive reduction in the amount of collagen occurred in the graft area and was negatively and linearly correlated with time (p < 0.001). VEGF expression was higher in grafted areas when compared to controls at 15 and 45 days after surgery and decreased with time (p < 0.001). Conclusion:The latex biomembrane as a matrix for partial bladder replacement in rabbits promotes temporary collagen deposition and stimulates the angiogenic process.

The two faces of titanium dioxide nanoparticles bio-camouflage in 3D bone spheroids

“…The calcium and phosphorous adsorbed ions present in NPs bio-camouflage, are fundamental for collagen secretion, bone mineralization and bone metabolism 63–67 . VEGF is a potent mediator of angiogenesis, also critical for bone development and regeneration 64,68–72 , however, its overexpression can contribute to bone resorption due to osteoclast recruitment 73 . In 3D models, spheroids (>100 µm) exhibit a more pronounced upregulation of VEGF secretion when compared to smaller ones 59,60,71 and there is a correlation in the decrease of VEGF secretion together with the reduction of collagen deposition 72 .…”

“…VEGF is a potent mediator of angiogenesis, also critical for bone development and regeneration 64,68–72 , however, its overexpression can contribute to bone resorption due to osteoclast recruitment 73 . In 3D models, spheroids (>100 µm) exhibit a more pronounced upregulation of VEGF secretion when compared to smaller ones 59,60,71 and there is a correlation in the decrease of VEGF secretion together with the reduction of collagen deposition 72 . Interestingly, in vitro studies using 2D osteoblast cells demonstrate that phagocytose of TiO 2 particles induce pro-inflammatory cytokine secretion with consequent suppression of collagen synthesis.…”

Effect of poly (l-lactic acid) scaffolds seeded with aligned diaphragmatic myoblasts overexpressing connexin-43 on infarct size and ventricular function in sheep with acute coronary occlusion

“…C-Kit encodes a tyrosine kinase receptor essential for proliferation, survival and migration of several stem cell types, including adult cardiac stem cells [29] and Nkx 2.5 gene encodes a homeobox-containing transcription factors that intervene in processes such as heart development [30]. Increased gene expression levels were observed in all treated groups, this suggests that is was the biomaterial, rather than the cells, which induced this effect [31]. Consistently, global LV function, as indicated by EF%, recovered to a similar extent in the three treated groups.…”