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AKKOÇ, TUNÇ

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AKKOÇ

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TUNÇ

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Open Access
Mesenchymal stem cells differentiate to retinal ganglion-like cells in rat glaucoma model induced by polystyrene microspheres
(2023-10-01) ERASLAN, MUHSİN; ÇERMAN, EREN; BOZKURT, SÜHEYLA; AKKOÇ, TUNÇ; ERASLAN M., ÇERMAN E., BOZKURT S., Genç D., Virlan A. T., Demir C. S., Akkoç T., Karaöz E., AKKOÇ T.
Aim: The study aimed to evaluate the differentiation ability of intravitreally injected rat bone marrow-derived mesenchymal stem cells (rBM-MSCs) to retinal ganglion-like cells in a polystyrene microsphere induced rat glaucoma model. Materials and Methods: The glaucoma rat model was generated via intracameral injection of 7 microliter polystyrene microspheres. Green fluorescence protein-labeled (GFP) rBM-MSCs were transplanted intravitreally at or after induction of ocular hypertension (OHT), depending on the groups. By the end of the fourth week, flat-mount retinal dissection was performed, and labeled against Brn3a, CD90, GFAP, CD11b, Vimentin, and localization of GFP positive rBM-MSCs was used for evaluation through immunofluorescence staining and to count differentiated retinal cells by flow cytometry. From 34 male Wistar albino rats, 56 eyes were investigated. Results: Flow cytometry revealed significantly increased CD90 and Brn3a positive cells in glaucoma induced and with rBM-MSC injected groups compared to control(P = 0.006 and P = 0.003 respectively), sham-operated (P = 0.007 and P < 0.001 respectively), and only rBM-MSCs injected groups (P = 0.002 and P = 0.009 respectively). Immunofluorescence microscopy revealed differentiation of GFP labeled stem cells to various retinal cells, including ganglion-like cells. rBM-MSCs were observable in ganglion cells, inner and outer nuclear retinal layers in rBM-MSCs injected eyes. Conclusion: Intravitreally transplanted rBM-MSCs differentiated into retinal cells, including ganglion-like cells, which successfully created a glaucoma model damaged with polystyrene microspheres. Promisingly, MSCs may have a role in neuro-protection and neuro-regeneration treatment of glaucoma in the future.
Open Access
FIP teşhisi konmuş kedilerden elde edilen periferal kan mononükleer hücreler ile kedi overinden elde edilen mezenkimal kök hücrenin immünolojik araştırılması
(2023-05-25) AKSU, MEHMET BURAK; AKKOÇ, TUNÇ; Güven N., Erhan M. N., Karayusuf K., Doğanay K., Kılıç S., Tunca Z., Aksu M. B., Akkoç T.
Giriş ve Amaç: Coronavirüsler hem insanlarda hem de hayvanlarda hafiften son derece şiddetli enfeksiyonlara kadar değişkenlik göstermektedir. Coronaviruslar çoğunlukla gastroentestinal ve solunum sistemi enfeksiyonlarına neden olurken bazıları ensefaliti ve hepatite neden olmaktadır. Kedilerin Enfeksiyöz Peritonitisi (FIP) ise kedi coronavirüslerinin (FCoV) neden olduğu bir enfeksiyondur. Çalışmamızda ise kedi ovaryum kaynaklı mezenkimal kök hücrelerin (O-MKH), FIP teşhisi konmuş kedilerden elde edilen periferal kan mononükleer hücrelere (PKMH) etkisinin in vitro ortamda araştırılıp değerlendirilmesi amaçlanmaktadır. Gereç ve Yöntem: Projemizde veteriner kliniğinde FIP tanısı konulmuş 5-13 yaşlarındaki kediler çalışmaya dahil edilecektir. Bu süreçte veteriner kliniğine gelen hastalardan FIP pozitif çıkan kedilerden hasta sahiplerinden alınan onam sonrasında 5cc periferal kan örneği alınacak ve Marmara Üniversitesi Tıp Fakültesi immünoloji anabilim dalında PKMH izole edilecektir. Ayrıca, kedi ovaryumlardan MKH izolasyonu gerçekleştirilecektir. İzole edilen PKMH ile O-MKH\"ların (+/-) ko-kültür işlemleri gerçekleştirilecektir. 5 günlük kültür işleminden sonra O-MKH\"nin FIP hasta PMKH\"larının canlılıkları üzerindeki etkileri akım sitometri yöntemi ile analiz edilecektir. Gerekli etik ve kurum izinleri alınmıştır. Bulgular: Yapılan ko-kültür çalışması sonrasında akım sitometri yöntemi ile PKMH’lerin canlılıklarındaki değişimler kıyaslanmıştır. Yapılan analizler sonucunda FIP kedilerin PKMH’ları MKH’nın olmadığı durumlarda canlılık oranı 55.6 (±5.2) iken MKH varlığında canlılıklarının 70.13 (±2.1)’e yükseldiği görülmüştür. Buna ek olarak, apoptoz geçiren PKMH’ların oranı MKH yokluğunda 34.7 (±4.4) iken MKH varlığında 12.7’e (±1.8) düştüğü gözlenmiştir. Hastalardaki PKMH’ların sağlıklı kedilerin durumları ile kıyaslandığında ise FIP hastası PKMH’ların canlılıkları MKH varlığında sağlıklı kedilerin PKMH’ların canlılık seviyesine yükseldiği görülmüştür. Sonuç: FIP hastalığına sahip olan kedilerin PKMH’larındaki canlılık oranının sağlıklı kediye kıyasla canlılık oranının beklendiği gibi daha düşük olduğu görülmüştür. Yine de MKH’nın varlığında FIP hastası kedilerin PKMH’larındaki canlılık seviyesinin sağlıklı kedilerin PKMH’lerin canlılık oranına yükseldiği görülmüştür. Ayrıca, MKH’ların apoptoz geçiren PKMH’ları FIP hastası kedilerde düşürdüğü gözlenmiştir. Elde edilen bu veriler çerçevesinde MKH’ların FIP hastalarında olumlu etkisi olduğu gözlenmektedir.
Open Access
Cytotoxicity of NeoMTA Plus, ProRoot MTA and Biodentine on human dental pulp stem cells
(ELSEVIER TAIWAN, 2021-07) AKKOÇ, TUNÇ; Birant, Sinem; Gokalp, Muazzez; Duran, Yazgul; Koruyucu, Mine; Akkoc, Tunc; Seymen, Figen
Background/purpose: Dental pulp stem cells (DPSCs) play a crucial role in the tis-sue healing process through odontoblast like cell differentiation. The aim of this study was to evaluate the biocompatibility and compare the potential invitro cytotoxic effects of NeoMTA Plus, ProRootMTA and Biodentine on human dental pulp stem cells (hDPSCs). Materials and methods: To assess the effects of NeoMTA Plus, ProRoot MTA and Biodentine ex-tracts at 1st, 3rd and 7th d on hDPCs, cell populations was determined by flow cytometry using an Annexin V detection kit. The data were analyzed statistically using the Kruskal-Wallis test. A p < 0.05 was considered as statistically significant. Results: All groups showed cell viability similar to that of the control group on 1st, 3rd and 7th d. Although Biodentine exhibited higher cell viability rates than the other material groups, no statistically significant differences were noted between the sampled days (p > 0.05). Conclusion: All materials extracts are not cytotoxic and do not induce apoptosis in the hDPSCs. These results suggest that all the tested materials can lead to positive outcomes when used as reparative biomaterials. (c) 2020 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).
Open Access
Clinical efficacy and immunological mechanisms of sublingual and subcutaneous immunotherapy in asthmatic/rhinitis children sensitized to house dust mite: an open randomized controlled trial
(WILEY, 2010-05-06) AKKOÇ, TUNÇ; Eifan, A. O.; Akkoc, T.; Yildiz, A.; Keles, S.; Ozdemir, C.; Bahceciler, N. N.; Barlan, I. B.
Background In children, the clinical efficacy and immunological mechanisms of sublingual immunotherapy (SLIT) compared with subcutaneous immunotherapy (SCIT) is still to be elucidated. Objectives To compare SLIT, SCIT and pharmacotherapy in relation to clinical efficacy and immunological mechanisms that govern its effect in asthmatic/rhinitis children who were sensitized to house dust mite (HDM). Methods In this single centre, prospective, randomized, controlled, open labelled, three parallel group trial, 48 patients mono-sensitized to HDM were randomized to receive either SLIT (n = 16), SCIT (n = 16) or pharmacotherapy alone (n = 16). Symptom, medication and visual analogue score (VAS) were collected and bronchial-nasal hyper-reactivity, skin prick tests, total-specific IgE were performed at baseline and 12 months after treatment. In addition, peripheral blood mononuclear cells were cultured with recombinant Der p 1 and Bet v 1 extracts and allergen-specific IL-4, IL-5, IL-13, IFN-gamma, IL-10, and TGF-beta secretions were measured. Results SLIT and SCIT demonstrated a significant reduction of total rhinitis and asthma symptom score, total medication score, VAS and skin reactivity to HDM (P<0.05) when compared with pharmacotherapy. A significant reduction of serum-specific HDM-IgE in SCIT and SLIT were observed. Moreover, titrated nasal provocative dose significantly increased in both immunotherapy groups when compared with the pharmacotherapy group. No adverse effects were reported in SLIT, while two patients demonstrated serious adverse events in SCIT. After 1 year of treatment, Der p 1-driven IL-10 significantly increased in SLIT compared with pharmacotherapy, whereas Bet v 1-driven TGF-beta (negative control) increased significantly in SLIT only. No changes were observed for Th1-Th2 cytokines. Conclusion Both SLIT and SCIT demonstrated clinical improvement compared with pharmacotherapy in asthma/rhinitis children sensitized to HDM.
Open Access
Canine adipose tissue stem cells induced with toll-like receptor agonists exhibit antibacterial activity against multi drug resistant pathogens
(2023-03-01) AKSU, MEHMET BURAK; AKKOÇ, TUNÇ; AKSU M. B., Yanilmaz O., AKKOÇ T.
Infections caused by antibiotic-resistant pathogens pose a major threat worldwide. There is an urgent need to develop effective strategies to solve this problem. The antibacterial activity of adult mesenchymal stem cells (MSCs) has recently been determined against various bacterial isolates. New approaches, such as Toll-like receptor activation, were used to enhance their antibacterial potency. This study examines the antibacterial activity of TLR agonist (TLR2/TLR1 and/or TLR2/TLR6) activated adipose-derived canine MSCs (AD-MSCs) on multidrug resistant isolates including Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa regarding bacterial growth, and minimum inhibitory concentration (MIC) determination. Effects on bacterial morphology were assessed by electron microscopy. Our results showed that the AD-MSCs conditioned medium primed with different TLR agonists inhibited the growth of E. coli and S. aureus, but it had a decreased effect on E. faecalis and P. aeruginosa. Despite this, AD-MSCs conditioned medium prepared with the combination of TLR agonists exhibited antibacterial activity against all isolates. These findings were in parallel with MIC levels of conditioned media. We conclude that adipose-derived canine MSCs primed with TLR agonists (TLR2/TLR1 and TLR2/TLR6 combination) possess antimicrobial activity against multi-drug resistant isolates of E. coli, S. aureus, E. faecalis and P. aeruginosa. Further studies for testing in in vivo models are being planned to assess the potential application of AD-MSCs as an adjunct treatment modality for multi drug resistant infections.
Open Access
Dental follicle mesenchymal stem cell administration ameliorates muscle weakness in MuSK-immunized mice
(BMC, 2015-12) AKKOÇ, TUNÇ; Ulusoy, Canan; Zibandeh, Noushin; Yildirim, Selin; Trakas, Nikolaos; Zisimopoulou, Paraskevi; Kucukerden, Melike; Tasli, Hatice; Tzartos, Socrates; Goker, Kamil; Tuzun, Erdem; Akkoc, Tunc
Background: Myasthenia gravis (MG) is an antibody-mediated autoimmune disease of the neuromuscular junction (NMJ), mostly associated with acetylcholine receptor (AChR) antibodies. Around 5-10 % of MG patients show antibodies to muscle-specific tyrosine kinase (MuSK). Mesenchymal stem cell (MSC) administration has been shown to ameliorate muscle weakness in the experimental autoimmune myasthenia gravis (EAMG) model induced by AChR immunization. Methods: To investigate the efficacy of stem cell treatment in MuSK-related EAMG, clinical and immunological features of MuSK-immunized mice with or without dental follicle MSC (DFMSC) treatment were compared. Results: MuSK-immunized mice intravenously treated with DFMSC after second and third immunizations showed significantly lower EAMG incidence and severity and reduced serum anti-MuSK antibody, NMJ IgG, and C3 deposit levels and CD11b+ lymph node cell ratios. Moreover, lymph node cells of DFMSC-administered mice showed reduced proliferation and IL-6 and IL-12 production responses to MuSK stimulation. By contrast, proportions of B and T cell populations and production of a wide variety of cytokines were not affected from DFMSC treatment. Conclusions: Our results suggest that DFMSC treatment shows its beneficial effects mostly through suppression of innate immune system, whereas other immune functions appear to be preserved. Stem cell treatment might thus constitute a specific and effective treatment method in MuSK-associated MG.
Open Access
The Induction of IL-33 in the Sinus Epithelium and Its Influence on T-Helper Cell Responses
(PUBLIC LIBRARY SCIENCE, 2015-05-01) AKKOÇ, TUNÇ; Soyka, Michael B.; Holzmann, David; Basinski, Tomasz M.; Wawrzyniak, Marcin; Bannert, Christina; Buergler, Simone; Akkoc, Tunc; Treis, Angela; Rueckert, Beate; Akdis, Muebeccel; Akdis, Cezmi A.; Eiwegger, Thomas
Background Chronic rhinosinusitis (CRS) is characterized by epithelial activation and chronic T-cell infiltration in sinonasal mucosa and nasal polyps. IL-33 is a new cytokine of the IL-1 cytokine family that has a pro-inflammatory and Th2 type cytokine induction property. The role of IL-33 in the pathomechanisms of CRS and its interaction with other T cell subsets remain to be fully understood. Methods The main trigger for IL-33 mRNA expression in primary human sinonasal epithelial cells was determined in multiple cytokine and T-cell stimulated cultures. The effects of IL-33 on naive, Th0 and memory T-cells was studied by PCR, ELISA and flow cytometry. Biopsies from sinus tissue were analyzed by PCR and immunofluorescence for the presence of different cytokines and receptors with a special focus on IL-33. Results IL-33 was mainly induced by IFN-gamma in primary sinonasal epithelial cells, and induced a typical CRSwNP Th2 favoring cytokine profile upon co-culture with T-helper cell subsets. IL-33 and its receptor ST2 were highly expressed in the inflamed epithelial tissue of CRS patients. While IL-33 was significantly up-regulated in the epithelium for CRSsNP, its receptor was higher expressed in sinus tissue from CRSwNP. Conclusions production, which could both contribute to a further increase of an established Th2 profile in CRSwNP.The present study delineates the influence of IL-33 in upper airway epithelium and a potential role of IL-33 in chronic inflammation of CRSwNP by enhancing Th2 type cytokine
Open Access
Effect of Dental Follicle Mesenchymal Stem Cells on Th1 and Th2 Derived Naive T Cells in Atopic Dermatitis Patients
(MARMARA UNIV, INST HEALTH SCIENCES, 2019-08-31) GÖKER, MEHMET KAMİL; Zibandeh, Noushin; Genc, Deniz; Ozgen, Zuleyha; Duran, Yazgul; Kasap, Nurhan; Goker, Kamil; Baris, Safa; Ergun, Tulin; Akkoc, Tunc
Objective: The purpose of our study is to investigate the immunomodulatory effects of Dental Follicle Mesenchymal Stem Cells (DF-MSCs) on lymphocytes isolated from peripheral blood of Atopic Dermatitis (AD) patients, a Th2 disease and psoriasis, a Th1 / Th17 disease and compare them with healthy individuals in vitro. Methods: Patients with the AD (n = 9) and psoriasis (n = 6) who are followed up in Marmara University Pediatric Allergy and Immunology and Dermatology outpatient clinics and healthy subjects (n = 6) were included. Peripheral Blood Mononuclear Cells (PBMCs) were isolated from 20 ml of venous blood of all participants. Cells were cultured for 72 hours in the absence and presence of DF-MSCs with anti-CD3/anti-CD28 stimulation or without stimulation. At the end of this period, CD4+ and CD8+ T lymphocyte proliferation and cytokine levels from the culture supernatants were analyzed by flow cytometry. Results: In the presence of DF-MSCs, proliferation ratio was suppressed in both CD4+ and CD8+ cells in AD and psoriasis patients (p<0,05). IFN-gamma levels significantly increased in AD patients in the presence of DF-MSCs (p<0,05) whereas decreased significantly in psoriasis patients in the presence of DF-MSCs (p<0,05). IL-4 levels significantly decreased in AD patients in the presence of DF-MSCs (p<0,05) but remained unchanged in psoriasis patients (p>0,05). IL-10 increased significantly in both groups in the presence of DF-MSCs (p<0,05). Conclusion: Our results support immunoregulatory effects of DF-MSCs on both AD and psoriasis which are Th2 and Th1 / Th17 dominant diseases respectively. Our evidence-based results demonstrated that DF-MSCs could have a beneficial therapeutic implication for inflammatory skin diseases.
Open Access
Intranasal ovalbumin immunotherapy with mycobacterial adjuvant promotes regulatory T cell accumulation in lung tissues
(WILEY, 2018-08) AKKOÇ, TUNÇ; Akkoc, Tunc; Genc, Deniz; Zibandeh, Noushin; Akkoc, Tolga
Allergen-specific immunotherapy to induce T regulatory cells in the periphery has been used to treat allergic diseases. Mycobacteria can be used as an adjuvant for inducing T regulatory cells. However, it is unclear whether intranasal immunotherapy in combination with Mycobacteria adjuvant induces regulatory T cell differentiation and attenuates allergic responses in vivo. To investigate the role of intranasal ovalbumin (OVA) treatment alone and in combination with Mycobacteria vaccae, proportions of FoxP3(+) regulatory T cells and anti-inflammatory responses were evaluated in a murine model of asthma that was established in three groups of bicistronic Foxp3(EGFP) reporter BALB/c mice. Before establishment of the asthma model, two groups of mice received intranasal OVA immunotherapy and one also received simultaneous s.c. M. vaccae. Expression of CD4(+)CD25(+)Foxp3(+EGFP+) T cells in the lung and spleen was analyzed by flow cytometry and the cytokine profiles of allergen-stimulated lung and spleen lymphocytes assessed. The intranasal OVA immunotherapy group showed greater expression of CD4(+)CD25(+)Foxp3(+EGFP+) T cells in the spleen whereas in the group that also received M. vaccae such greater expression was demonstrated in the lung. Additionally, the proportion of IL-10 and IFN--secreting splenocytes was greater in the intranasal OVA+M. vaccae group. CD25 neutralization decreased CD4(+)Foxp3(+) cells more than other groups. In parallel with this finding, production of IL-10 and IFN- was down-regulated. Mucosal administration of OVA antigen results in a greater proportion of CD4(+)Foxp3(+) T cells in the spleen. IL-10 and IFN- induced by intranasal OVA immunotherapy and M. vaccae administration is down-regulated after CD25 neutralization.
Open Access
Sublingual immunotherapy in children with allergic rhinoconjunctivitis mono-sensitized to house-dust-mites: A double-blind-placebo-controlled randomised trial
(W B SAUNDERS CO LTD, 2013-09) AKKOÇ, TUNÇ; Aydogan, Metin; Eifan, Aarif O.; Keles, Sevgi; Akkoc, Tunc; Nursoy, Mustafa A.; Bahceciler, Nerrin N.; Barlan, Isil B.
Background: Although sublingual immunotherapy (SLIT) has been demonstrated to be a safe and efficient treatment in children with seasonal allergic rhinitis (AR), there is little evidence on the efficacy of SLIT with house-dust-mite (HDM) extract in children with isolated perennial AR. Objectives: We sought to assess the clinical efficacy and safety of HDM-SLIT in children with isolated allergic rhinitis-conjunctivitis mono-sensitized to HDM without asthma symptoms. Methods: Twenty-two children (aged 5-10 years) with perennial AR and conjunctivitis symptoms mono-sensitized to Dermatophagoides pteronyssinus and Dermatophagoides farinae were enrolled. During a 2 months run-in period, symptom and medication scores, lung functions, bronchial hyperreactivity, nasal provocation and skin prick tests were evaluated. Subjects were randomized to active or placebo using a double-blind method. A total of eighteen subjects were randomised to receive either active SLIT or placebo for 12 months. Daily symptom and medication scores, baseline lung functions, bronchial hyperreactivity, nasal provocation and skin prick tests were recorded and re-evaluated at the end of treatment. Results: After one year of treatment, no significant differences were detected in the between groups and within group comparisons based on total rhinitis symptom/medication scores (p > 0.05). Skin reactivity to Dermatophagoides pteronyssinus was significantly reduced in HDM-SLIT compared to placebo group (p = 0.018). A significant reduction in nasal sensitivity was observed in SLIT group after one year treatment when compared to baseline (p = 0.04). Total conjunctivitis symptoms were reduced significantly in both active and lacebo group at the end of treatment compared to baseline. The proportion of patients with nonspecific bronchial hyperreactivity increased to almost 3-fold in placebo group compared to baseline. Conclusion: HDM-SLIT was not superior to placebo in reducing isolated rhinoconjunctivitis symptoms within 12 months of treatment. However, HDM-SLIT has a modulating effect on allergen-specific nasal and skin reactivity in isolated perennial AR children. Clinical Trial Registration: The trial was registered at Anzctr.org.au number, ACTRN1261 3000315718. (C) 2013 Elsevier Ltd. All rights reserved.