Browsing by Author "Yazici, Ayse C."

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Adipose-Derived Stem Cells Enhance Axonal Regeneration through Cross-Facial Nerve Grafting in a Rat Model of Facial Paralysis
(2016) Abbas, Ozan L.; Borman, Huseyin; Uysal, Cagri A.; Gonen, Zeynep B.; Aydin, Leyla; Helvacioglu, Fatma; Ilhan, Sebnem; Yazici, Ayse C.; https://orcid.org/0000-0001-6236-0050; https://orcid.org/0000-0002-6026-0045; https://orcid.org/0000-0002-3132-242X; 27465163; AAJ-2949-2021; AAH-8887-2021; AAS-6810-2021
Background: Cross-face nerve grafting combined with functional muscle transplantation has become the standard in reconstructing an emotionally controlled smile in complete irreversible facial palsy. However, the efficacy of this procedure depends on the ability of regenerating axons to breach two nerve coaptations and reinnervate endplates in denervated muscle. The current study tested the hypothesis that adipose-derived stem cells would enhance axonal regeneration through a cross-facial nerve graft and thereby enhance recovery of the facial nerve function. Methods: Twelve rats underwent transection of the right facial nerve, and cross-facial nerve grafting using the sciatic nerve as an interpositional graft, with coaptations to the ipsilateral and contralateral buccal branches, was carried out. Rats were divided equally into two groups: a grafted but nontreated control group and a grafted and adipose-derived stem cell-treated group. Three months after surgery, biometric and electrophysiologic assessments of vibrissae movements were performed. Histologically, the spectra of fiber density, myelin sheath thickness, fiber diameter, and g ratio of the nerve were analyzed. Immunohistochemical staining was performed for the evaluation of acetylcholine in the neuromuscular junctions. Results: The data from the biometric and electrophysiologic analysis of vibrissae movements, immunohistochemical analysis, and histologic assessment of the nerve showed that adipose-derived stem cells significantly enhanced axonal regeneration through the graft. Conclusion: These observations suggest that adipose-derived stem cells could be a clinically translatable route toward new methods to enhance recovery after cross-facial nerve grafting.
Comparison of Intraocular Pressure Measurements Between Goldmann Applanation Tonometry and Reichert 7 Noncontact Tonometry
(2015) Gungor, Sirel G.; Akman, Ahmet; Yazici, Ayse C.; 0000-0002-3132-242X; 0000-0001-6178-8362; 24145288; AAS-6810-2021; AAD-5967-2021
Purpose:The aim of this study was to compare the Reichert 7 (R7) noncontact tonometry with Goldmann applanation tonometry (GAT) and to determine the influence of central corneal thickness (CCT) in these measurements in the healthy population.Design:A prospective cross-sectional study.Methods:Intraocular pressure (IOP) of the right eyes of 120 patients was measured with GAT and R7. All patients were free of glaucoma. All the measurements were carried out between 7 am and 9 am The measurements with the R7 were taken in the automatic mode. After 15 minutes, IOP with GAT was measured followed by pachymetry. The R7 provided a Goldmann-correlated IOP (IOPg) and a corneal-compensated IOP (IOPcc).Results:The mean age of the patients was 53.919.3 (range, 26 to 85 y). The male/female ratio was 0.9/1. When R7 measurements were compared with GAT measurements, R7 measurements (both IOPcc and IOPg) were significantly higher than GAT measurements (P0.001). Besides that, IOPcc was significantly higher than IOPg (P0.001). There was a significant positive linear relationship between IOPcc and GAT (r=0.761, P0.001), and similar relationship between IOPg and GAT (r(2)=0.739, P0.001). The mean CCT was 545.9 +/- 33.2 m (range, 476 to 634 m). A weak correlation was observed between CCT and GAT (r=0.196, P=0.032). There was a significant correlation between CCT and IOPg (r=0.283, P=0.02). The correlation between CCT and IOPcc was not statistically significant (r=0.123, P=0.179).Conclusions:IOP values of R7 are higher than GAT values. However, IOPg was observed more coherent to the GAT values than IOPcc. IOPcc should be an evaluation factor along with GAT or IOPg in glaucoma examination.
Inhibition of the Notch Pathway Promotes Flap Survival by Inducing Functional Neoangiogenesis
(2015) Abbas, Ozan Luay; Borman, Huseyin; Terzi, Yunus K.; Terzi, Aysen; Bayraktar, Nilufer; Ozkan, Burak; Yazici, Ayse C.; 0000-0002-7886-3688; 0000-0003-3093-8369; 0000-0002-1225-1320; 0000-0002-3132-242X; 0000-0001-5612-9696; 25180956; Y-8758-2018; AAI-5063-2020; F-7546-2013; AAS-6810-2021; B-4372-2018
Objective The Notch pathway seems to function as an antiangiogenic factor, negatively regulating the sprouting effect of vascular endothelial growth factor (VEGF). This function is well defined in embryonic and tumor vasculature. However, little is known about its function in ischemia-induced angiogenesis. In the first part of this study, we investigated the role of Notch in reparative angiogenesis after ischemia. In the second part, we hypothesized that anti-Notch therapy will result in increased angiogenic sprouting. We analyzed the effect of Notch inhibition in the induction of angiogenic sprouting. Methods In the first part, we investigated the effect of ischemia on the Notch ligand delta-like ligand 4 (DLL4). Twenty rats were divided equally into 2 groups. In the surgery group, dorsal skin flap was used as model of ischemia. In the control group, no surgical procedure was performed. DLL4 and VEGF gene expressions were assessed. Immunohistochemical staining was used for detection of DLL4 in tissue materials. Plasma levels of VEGF and DLL4 were measured. In the second part, we investigated the effect of Notch inhibition using a gamma-secretase inhibitor (GSI) on inducing neoangiogenesis. Twenty rats were assigned to 2 equal groups. In all animals, dorsal skin flap was raised and sutured back into its bed. Animals in the GSI-treated group received GSI intravenously after surgery for 3 days. Saline was administered in the control group. Necrotic area measurements, microangiography, and histologic evaluations were performed to compare groups. Results In the first part, VEGF and DLL expressions increased in ischemic tissues (P < 0.01). Immunohistochemical analysis revealed that DLL4 expression was upregulated in capillary endothelial cells after ischemia. Plasma levels for VEGF and DLL4 were higher in the animals that underwent surgery (P < 0.01). In the second part, GSI treatment resulted in higher flap survival rates (P < 0.05). Microscopic analysis exhibited increase in the number of microvascular structures after GSI treatment (P < 0.05). Microangiographic evaluation showed that neovascularization increased in the GSI-applied flaps. Conclusions We present an evidence for the importance of the Notch pathway in the regulation of ischemia-induced angiogenesis. Notch inhibition promotes flap survival by creating a neovasculature that has an increase in vascular density.
The Notch Pathway Is A Critical Regulator of Angiogenesis in A Skin Model of Ischemia
(2015) Abbas, Ozan L.; Borman, Huseyin; Terzi, Yunus K.; Terzi, Aysen; Bayraktar, Nilufer; Yazici, Ayse C.; 0000-0002-1225-1320; 0000-0002-7886-3688; 0000-0001-5612-9696; 0000-0002-3132-242X; 25834117; F-7546-2013; Y-8758-2018; B-4372-2018; AAS-6810-2021
The Notch pathway is definitely required for normal vascular development. Although the contribution of Notch in postnatal angiogenesis is the focus of intense investigation, the implication of Notch in reparative neovascularization in the skin remains unexplored. In this study, we investigated Notch changes using a skin model of ischemia. Thirty Sprague-Dawley rats were divided into two groups. In the surgery group (n = 24), a caudally based dorsal skin flap was raised and sutured back into its initial position. In the control group, no surgical procedure was performed. Tissue biopsies were obtained at different time intervals. Tissue specimens were assessed for Delta-like ligand 4 (DLL4) and vascular endothelial growth factor (VEGF) gene expression by real-time polymerase chain reaction (PCR). Immunohistochemical staining was used for detection of DLL4 in tissue materials. Quantitative assessment of skin flap microvasculature was made. Compared with normoperfused tissue, VEGF and DLL4 expressions increased significantly (p < 0.01). Immunohistochemical analysis revealed weak and patchy expression of DLL4 in microvascular endothelial cells of normoperfused tissues. Conversely, DLL4 expression was upregulated in capillary endothelial cells after ischemia. In conclusion, in this study we have shown that the Notch ligand DLL4 is upregulated in skin tissue after ischemia. A deeper understanding of these fundamental principles will aid in the development of new avenues for the treatment of blood vessel-related skin pathologies.