Researcher:
Albayrak, Özgür

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Özgür

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Albayrak

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Albayrak, Özgür

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Now showing 1 - 10 of 14
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    Publication
    JAK2V617F mutation in endothelial cells of patients with Atherosclerotic Carotid disease
    (Galenos Publishing House, 2024) Diz-Küçükkaya, Reyhan; İyigün, Taner; Eker, Candan; Günel, Tuba; N/A; Albayrak, Özgür; Koç University Research Center for Translational Medicine (KUTTAM); N/A
    Objective: It has been shown that clonal mutations occur in hematopoietic stem cells with advancing age and increase the risk of death due to atherosclerotic vascular diseases, similarly to myeloproliferative neoplasms. Endothelial cells (ECs) and hematopoietic stem cells develop from common stem cells called hemangioblasts in the early embryonic period. However, the presence of hemangioblasts in the postnatal period is controversial. In this study, JAK2 gene variants were examined in patients with atherosclerotic carotid disease and without any hematological malignancies. Materials and Methods: Ten consecutive patients (8 men and 2 women) with symptomatic atherosclerotic carotid stenosis were included in this study. ECs (CD31+CD45-) were separated from tissue samples taken by carotid endarterectomy. JAK2 variants were examined in ECs, peripheral blood mononuclear cells, and oral epithelial cells of the patients with next-generation sequencing. Results: The median age of the patients was 74 (range: 58-80) years and the median body mass index value was 24.44 (range: 18.42-30.85) kg/m2. Smoking history was present in 50%, hypertension in 80%, diabetes in 70%, and ischemic heart disease in 70% of the cases. The JAK2V617F mutation was detected in the peripheral blood mononuclear cells of 3 of the 10 patients, and 2 patients also had the JAK2V617F mutation in their ECs. The JAK2V617F mutation was not found in the oral epithelial cells of any of the patients. Conclusion: In this study, for the first time in the literature, we showed that the JAK2V617F mutation was found somatically in both peripheral blood cells and ECs in patients with atherosclerosis. This finding may support that ECs and hematopoietic cells originate from a common clone or that somatic mutations can be transmitted to ECs by other mechanisms. Examining the molecular and functional changes caused by the JAK2V617F mutation in ECs may help open a new avenue for treating atherosclerosis. © 2024 by Turkish Society of Hematology.
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    Publication
    T-cell sub group analysis and T-cell exhaustion after autologous stem cell transplantation in lymphoma patients
    (Springernature, 2023) Somay, Kayra; Birtaş Ateşoğlu, Elif; Albayrak, Özgür; Kızılırmak, Ali Burak; Akan, Tuba; Ferhanoğlu, Ahmet Burhan; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Health Sciences; School of Medicine; Koç University Hospital
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    PublicationOpen Access
    Dysbiosis in pregnant mice induced by transfer of human vaginal microbiota followed by reversal of pathological changes in the uterus and placenta via progesterone treatment
    (BMC, 2024) Department of Computer Engineering;Department of Chemical and Biological Engineering; Kuyucu, Gülin Özcan; Talay, Zeynep Gülce; Paerhati, Erxiati; Eren, Özgür Can; Coşkun, Nilhan; Şahin, Deniz; Alnajjar, Iman; Albayrak, Özgür; Gürsoy, Attila; Keskin, Özlem; Çelik, Ebru; Can, Füsun; Koç Üniversitesi İş Bankası Enfeksiyon Hastalıkları Uygulama ve Araştırma Merkezi (EHAM) / Koç University İşbank Center for Infectious Diseases (KU-IS CID); Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Health Sciences; College of Engineering; School of Medicine; Koç University Hospital
    Objective The vaginal microbiota dysbiosis induces inflammation in the uterus that triggers tissue damage and is associated with preterm birth. Progesterone is used to prevent labor in pregnant women at risk of preterm birth. However, the mechanism of action of progesterone still needs to be clarified. We aimed to show the immunomodulatory effect of progesterone on the inflammation of uterine tissue triggered by dysbiotic vaginal microbiota in a pregnant mouse model.Methods Healthy (n = 6) and dysbiotic (n = 7) vaginal microbiota samples isolated from pregnant women were transferred to control (n = 10) and dysbiotic (n = 14) pregnant mouse groups. The dysbiotic microbiota transferred group was treated with 1 mg progesterone (n = 7). Flow cytometry and immunohistochemistry analyses were used to evaluate inflammatory processes. Vaginal microbiota samples were analyzed by 16 S rRNA sequencing.Results Vaginal exposure to dysbiotic microbiota resulted in macrophage accumulation in the uterus and cellular damage in the placenta. Even though TNF and IL-6 elevations were not significant after dysbiotic microbiota transplantation, progesterone treatment decreased TNF and IL-6 expressions from 49.085 to 31.274% (p = 0.0313) and 29.279-21.216% (p = 0.0167), respectively. Besides, the macrophage density in the uterus was reduced, and less cellular damage in the placenta was observed.Conclusion Analyzing the vaginal microbiota before or during pregnancy may support the decision for initiation of progesterone therapy. Our results also guide the development of new strategies for preventing preterm birth.
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    Prevalence of apis, vespula and polistes sensitivity in venom allergic patients in Turkey
    (Wiley, 2020) Dursun, A. B.; Sonmez, H.; Gelincik, A.; Yigit, O. O.; Albayrak, O.; Celebioglu, E.; Sahiner, U. M.; Buyuktiryaki, B.; Erdogan, T.; Firtina, S.; Taylan, D.; Soyer, O.; Karakaya, G.; Kalyoncu, A. F.; Sekerel, B.; N/A; Hela, Francesko; Öztürk, Ayşe Bilge; Saçkesen, Cansın; Albayrak, Özgür; Other; Faculty Member; Faculty Member; Researcher; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); N/A; N/A; School of Medicine; N/A; N/A; 147629; 182537; N/A
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    Novel CD20+innate lymphoid cells show increased killing capacity and are related to multiple sclerosis prognosis
    (Sage Publications Ltd, 2022) Üzülmez, M.; Baytekin, I.; Esendağlı, G.; Meinl, I.; Köseoğlu, M.; Yüksel, B.; Soysal, A.; Meinl, E.; N/A; Albayrak, Özgür; Doran, Tansu; Kızılırmak, Ali Burak; Soylu, Kemal; Erdem, Haluk; Researcher; PhD Student; PhD Student; Other; Other; N/A; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); N/A; Graduate School of Health Sciences; Graduate School of Health Sciences; N/A; N/A; N/A; N/A; N/A; N/A
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    Effect of BTN162b2 and CoronaVac boosters on humoral and cellular immunity of individuals previously fully vaccinated with CoronaVac against SARS-CoV-2: A longitudinal study
    (Wiley, 2022) Midilli, Kenan; Tok, Yesim; Yavuz, Serap Simsek; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; N/A; Kuloğlu, Zeynep Ece; El, Rojbin; Esken, Gülen Güney; Talay, Zeynep Gülce; Barlas, Tayfun; Kuşkucu, Mert Ahmet; Albayrak, Özgür; Doğan, Özlem; Ergönül, Önder; Can, Füsun; Researcher; Master Student; Other; Researcher; Researcher; Faculty Member; Researcher; Faculty Member; Faculty Member; Faculty Member; Koç Üniversitesi İş Bankası Enfeksiyon Hastalıkları Uygulama ve Araştırma Merkezi (EHAM) / Koç University İşbank Center for Infectious Diseases (KU-IS CID); Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); N/A; Graduate School of Sciences and Engineering; N/A; N/A; N/A; School of Medicine; N/A; School of Medicine; School of Medicine; School of Medicine; N/A; N/A; N/A; N/A; N/A; N/A; Koç University Hospital; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 170418; 110398; 103165
    Background It is essential to know about immune response levels after booster doses of the two different types of vaccines, mRNA, and the inactivated, currently used against COVID-19. For this purpose, we aimed to determine the effects of BNT162b2 (BNT) and CoronaVac (CV) boosters on the humoral and cellular immunity of individuals who had two doses of CV vaccination. Methods The study was conducted in three centers (Koc University Hospital, Istanbul University Cerrahpasa Hospital, and Istanbul University, Istanbul Medical School Hospital) in Istanbul, Turkey. Individuals who had been previously immunized with two doses of CV and no history of COVID-19 were included. The baseline blood samples were collected 3-5 months after the second dose of CV. Follow-up blood samples were taken 1 and 3 months after administration of third doses of CV, or one dose of BNT boosters. Neutralizing antibody titers were measured by plaque reduction assay. The CD4+ T cell, CD8+ T cell, effector CD4+CD38+CD69+ T cell, and effector CD8+CD38+CD69+ T cell ratios were determined by flow cytometry. The intracellular IFN-gamma and IL-2 responses were measured by ELISpot assay. Results We found a 3.38-fold increase in neutralizing antibody geometric mean titers (NA GMT, 78.69) 1 month after BNT booster and maintained at the third month (NA GMT, 80). Nevertheless, in the CV booster group, significantly lower NA GMT than BNT after 1 month and 3 months were observed (21.44 and 28.44, respectively) (p < .001). In the ELISpot assay, IL-2 levels after BNT were higher than baseline and CV booster (p < .001) while IFN-gamma levels were significantly higher than baseline (p < .001). The CD8+CD38+CD69+ and CD4+CD38+CD69+ T cells were stimulated predominantly in the third month of the BNT boosters. Conclusion The neutralizing antibody levels after 3 months of the BNT booster were higher than the antibody levels after CV in fully vaccinated individuals. On the contrary, ratio of the effector T cells increased along with greater IFN-gamma activation after BNT booster. By considering the waning immunity, we suggest a new booster dose with BNT for the countries that already had two doses of primary CV regimens.
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    Identification of diagnostic and prognostic indicators of hypercoagulability in patients with pseudoexfoliation syndrome
    (Association for Research in Vision and Ophthalmology (ARVO), 2021) N/A; N/A; Narimanfar, Ghazal; Uğurel, Elif; Kesim, Cem; Zibandeh, Noushin; Albayrak, Özgür; Şahin, Afsun; Yalçın, Özlem; PhD Student; Resercher; Doctor; Resercher; Resercher; Faculty Member; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Health Sciences; School of Medicine; N/A; N/A; N/A; School of Medicine; School of Medicine; N/A; N/A; Koç University Hospital; N/A; N/A; 387367; N/A; N/A; 171267; 218440
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    Functional properties of CD56+CD20 natural killer cells and their relationship with demyelinating disorders
    (Sage Publications Ltd, 2021) Kizilirmak, A. B.; Uzulmez, M.; Baytekin, I.; Soylu, K.; Esendagli, G.; Meinl, I.; Koseoglu, M.; Yuksel, B.; Soysal, A.; Mainl, E.; Vural, A.; N/A; N/A; N/A; N/A; N/A; Albayrak, Özgür; Doran, Tansu; Kızılırmak, Ali Burak; Kolsuz, Selin; Erdem, Halil Eren; Researcher; PhD Student; PhD Student; Teaching Faculty; Undergraduate Student; Undergraduate Student; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); N/A; Graduate School of Health Sciences; Graduate School of Health Sciences; School of Medicine; School of Medicine; N/A; N/A; N/A; English Language Center; N/A; N/A; N/A; N/A; N/A; N/A
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    Impact of the ST101 clone on fatality among patients with colistin-resistant Klebsiella pneumoniae infection
    (Oxford University Press (OUP), 2018) Menekse, Şirin; Karahan, Salih Nafiz; Azap, Oztem Kurt; Timurkaynak, Funda; Yavuz, Serap Şimşek; Basaran, Seniha; Yörük, Fugen; Azap, Alpay; Koculu, Safiye; Benzonana, Nur; N/A; N/A; N/A; N/A; N/A; N/A; Department of Industrial Engineering; N/A; N/A; N/A; Department of Industrial Engineering; Can, Füsun; İspir, Pelin; Ataç, Nazlı; Albayrak, Özgür; Demir, Tuana; Karaaslan, Doruk Can; Gönen, Mehmet; Lack, Nathan Alan; Ergönül, Önder; Kapmaz, Mahir; Faculty Member; Master Student; Researcher; Researcher; Undergraduate Student; Undergraduate Student; Faculty Member; Faculty Member; Faculty Member; Doctor; Koç Üniversitesi İş Bankası Enfeksiyon Hastalıkları Uygulama ve Araştırma Merkezi (EHAM) / Koç University İşbank Center for Infectious Diseases (KU-IS CID); School of Medicine; Graduate School of Health Sciences; N/A; N/A; School of Medicine; School of Medicine; College of Engineering; School of Medicine; School of Medicine; N/A; Koç University Hospital; 103165; N/A; N/A; N/A; N/A; N/A; 237468; 120842; 110398; N/A
    Objectives: We describe the molecular characteristics of colistin resistance and its impact on patient mortality. Methods: A prospective cohort study was performed in seven different Turkish hospitals. The genotype of each isolate was determined by MLST and repetitive extragenic palindromic PCR (rep-PCR). Alterations in mgrB were detected by sequencing. Upregulation of pmrCAB, phoQ and pmrK was quantified by RT-PCR. mcr-1 and the genes encoding OXA-48, NDM-1 and KPC were amplified by PCR. Results: A total of 115 patients diagnosed with colistin-resistant K. pneumoniae (ColR-Kp) infection were included. Patients were predominantly males (55%) with a median age of 63 (IQR 46-74) and the 30 day mortality rate was 61%. ST101 was the most common ST and accounted for 68 (59%) of the ColR-Kp. The 30 day mortality rate in patients with these isolates was 72%. In ST101, 94% (64/68) of the isolates had an altered mgrB gene, whereas the alteration occurred in 40% (19/47) of non-ST101 isolates. The OXA-48 and NDM-1 carbapenemases were found in 93 (81%) and 22 (19%) of the total 115 isolates, respectively. In multivariate analysis for the prediction of 30 day mortality, ST101 (OR 3.4, CI 1.46-8.15, P = 0.005) and ICU stay (OR 7.4, CI 2.23-29.61, P = 0.002) were found to be significantly associated covariates. Conclusions: Besides ICU stay, ST101 was found to be a significant independent predictor of patient mortality among those infected with ColR-Kp. A significant association was detected between ST101 and OXA-48. ST101 may become a global threat in the dissemination of colistin resistance and the increased morbidity and mortality of K. pneumoniae infection.
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    PublicationOpen Access
    Engineering human stellate cells for beta cell replacement therapy promotes in vivo recruitment of regulatory T cells
    (Elsevier, 2019) N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Oran, Dilem Ceren; Lokumcu, Tolga; Bal, Tuğba; İnceoğlu, Yasemin; Albayrak, Özgür; Erkan, Murat Mert; Kurtoğlu, Metin; Can, Füsun; Önder, Tuğba Bağcı; Kızılel, Seda; Akolpoğlu, Mükrime Birgül; Faculty Member; Faculty Member; Master Student; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Sciences and Engineering; Graduate School of Health Sciences; College of Engineering; School of Medicine; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 103165; 184359; 28376; N/A
    Type 1 diabetes (T1D) is an autoimmune disease characterized by destruction of pancreatic β cells. One of the promising therapeutic approaches in T1D is the transplantation of islets; however, it has serious limitations. To address these limitations, immunotherapeutic strategies have focused on restoring immunologic tolerance, preventing transplanted cell destruction by patients’ own immune system. Macrophage-derived chemokines such as chemokine-ligand-22 (CCL22) can be utilized for regulatory T cell (Treg) recruitment and graft tolerance. Stellate cells (SCs) have various immunomodulatory functions: recruitment of Tregs and induction of T-cell apoptosis. Here, we designed a unique immune-privileged microenvironment around implantable islets through overexpression of CCL22 proteins by SCs. We prepared pseudoislets with insulin-secreting mouse insulinoma-6 (MIN6) cells and human SCs as a model to mimic naive islet morphology. Our results demonstrated that transduced SCs can secrete CCL22 and recruit Tregs toward ​the implantation site in vivo. This study is promising to provide a fundamental understanding of SC-islet interaction and ligand synthesis and transport from SCs at the graft site for ensuring local immune tolerance. Our results also establish a new paradigm for creating tolerable grafts for other chronic diseases such as diabetes, anemia, and central nervous system (CNS) diseases, and advance the science of graft tolerance.