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Featured researches published by Coskun Kaya.


American Journal of Nephrology | 2012

Early arterial stiffness and inflammatory bio-markers in normotensive polycystic kidney disease patients.

Ismail Kocyigit; Mehmet Gungor Kaya; Ozcan Orscelik; Coskun Kaya; Mahmut Akpek; Halid Zengin; Murat Hayri Sipahioglu; Aydin Unal; Mahmut Ilker Yilmaz; Bulent Tokgoz; Oktay Oymak; Jonas Axelsson

Background/Aims: Cardiovascular disease is the main cause of morbidity and mortality in autosomal-dominant polycystic kidney disease (ADPKD) patients. To clarify temporal relationship between ADPKD, hypertension and the loss of renal function, we examined these factors in patients with early-stage ADPKD who did not yet have hypertension. Methods: Fifty patients with ADPKD (42% males, 36.6 ± 9.9 years, no blood pressure medication) and 50 healthy controls (44% males, 35.4 ± 6.4 years) were studied cross-sectionally. Pulse wave velocity (PWV), cardiac morphology and function, aortic elastic indexes, estimated glomerular filtration rate (eGFR), 24-hour ambulatory blood pressure, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and highly sensitive C-reactive protein (hs-CRP) were measured in all participants, using conventional methods. Results: Despite a normal blood pressure, aortic stiffness index and pulse wave velocity values were increased in patients compared to controls (6.8 ± 4.7 vs. 5.1 ± 3.3, p = 0.043 and 9.6 ± 1.3 vs. 5.8 ± 1.1 m/s, p < 0.001). In univariate analysis, IL-6, TNF-α, hs-CRP and eGFR were all significantly correlated with PWV. The independence of these correlations were analyzed in a regression model, and showed PWV to be significantly predicted by IL-6, TNF-α and hs-CRP. Conclusion: Increased arterial stiffness and pulse wave velocity are early manifestations of ADPKD appearing before hypertension or reduced eGFR. However, these vascular abnormalities are related to signs of systemic low grade inflammation, suggesting a common pathophysiological mechanism apparently present also in other vascular diseases but yet to be elucidated.


Blood Pressure | 2014

Masked hypertension in renal transplant recipients

Mehmet Kayrak; Enes Elvin Gul; Coskun Kaya; Yalcin Solak; Kultigin Turkmen; Raziye Yazici; Ibrahim Guney; Lutfullah Altintepe; Suleyman Turk; Kurtulus Ozdemir

Abstract Purpose: Arterial hypertension is a risk factor affecting graft function in renal transplant recipients (RTRs). In pediatric RTRs, high prevalence of masked and nocturnal hypertension was reported. Most of the RTRs had a history of hypertension and some of them were normotensive at outpatient visits whereas home blood pressure (BP) levels were higher. Masked hypertension (MHT) is defined as a normal office BP but an elevated ambulatory BP. Previous reports have demonstrated the detrimental role of MHT in clinical outcomes in hypertensive patients. However, the true prevalence of MHT in RTRs is yet to be defined. Methods: A total of 113 RTRs (mean age 44 ± 16 years, 72 males, 41 females) with normal office BP (< 140/90 mmHg) were enrolled to the study from the outpatient renal transplantation clinic. Ambulatory BP monitoring (ABPM) was performed in all participants for a 24-h period. Average daytime BP values above 135 mmHg systolic and 85 mmHg diastolic were defined as MHT. Results: The prevalence of MHT in our cohort was 39% (n = 45). Fasting glucose and C-reactive protein levels were higher in patients with MHT compared with normal BP group (p = 0.02 and p = 0.04, respectively). RTRs with deceased donor type had higher prevalence of MHT than RTRs with living donor (40% vs 19%, p = 0.003). In multivariate analysis, deceased donor type could predict the MHT independent of age, gender, office systolic BP level, diabetes mellitus, serum creatinine, C-reactive protein, and glucose levels (OR = 3.62, 95% CI 1.16–11.31, p = 0.03). Conclusion: We demonstrated an increased prevalence of MHT in a typical renal transplant cohort. In addition, transplantation from a deceased donor may be a predictor of MHT. The prevalence of MHT may help to explain high rate of cardiovascular events in RTRs. Therefore, routine application of ABPM in RTRs may be plausible, particularly in RTRs with deceased donor type.


Clinical and Applied Thrombosis-Hemostasis | 2014

Red Cell Distribution Width and Mean Platelet Volume in Amyloidosis

Emre Erdem; Dilek Erdem; Melda Dilek; Coskun Kaya; Ahmet Karataş; Engin Kut; Murat Çoban; Kuddusi Cengiz; Nurol Arık; Tekin Akpolat

We aimed to determine whether red cell distribution width (RDW) and mean platelet volume (MPV) values differ between patients with reactive amyloid A (AA) amyloidosis due to chronic inflammatory disease and in healthy participants. In this study, 33 patients with AA amyloidosis and 40 age- and sex-matched healthy controls were enrolled. Erythrocyte sedimentation rate (ESR), RDW, platelet count (PLT), and MPV levels were retrospectively obtained from our computerized patient database. We found RDW, ESR, and PLT levels to be significantly higher in patients with AA amyloidosis compared with the controls (P < .0001). Mean platelet volume was significantly lower in patients with amyloidosis (P < .0001). Inflammatory diseases such as AA amyloidosis may demonstrate low MPV and high RDW levels.


Renal Failure | 2015

Catheter-related atrial thrombus: tip of the iceberg?

Melda Dilek; Coskun Kaya; Ahmet Karataş; Ismail Ozer; Nurol Arık; Okan Gulel

Abstract Although guidelines recommend catheters as a last resort for establishing a vascular access in patients undergoing dialysis, they continue to be used widely for this purpose. Catheter-related atrial thrombus (CRAT) is rarely reported in this group of patients, and it can lead to serious complications. The aim of this study was to determine the incidence of CRAT in patients undergoing hemodialysis with permanent-tunneled catheters. A total of 50 patients undergoing hemodialysis with permanent catheters were included in this study. The diagnosis of CRAT was based on transthoracic echocardiography findings. Thrombus was present in nine patients (18%) and related to the tip of the catheter in all cases. Except for one patient with two foci of thrombus, all patients had a single focus. There were no significant associations between the development of thrombus and the duration of catheter use or the location of the catheter. Furthermore, catheter-related atrial thrombus did not appear to have a significant effect on mortality. The asymptomatic character of CRAT can be responsible for the low reporting rates, and its exact role in increased mortality and morbidity related with catheter use remains unknown. While planning management strategies, information on different options for vascular access routes and possible catheter-related complications should be provided to all patients who will undergo dialysis, together with a discussion involving other replacement alternatives for end-stage renal disease.


Blood Pressure | 2012

Impairment of heart rate recovery index in autosomal-dominant polycystic kidney disease patients without hypertension.

Ozcan Orscelik; Ismail Kocyigit; Oguzhan Baran; Coskun Kaya; Orhan Dogdu; Halit Zengin; Serhat Karadavut; Ömer Gedikli; Engin Kut; Mustafa Duran; Bekir Calapkorur; Bulent Tokgoz; Mehmet Gungor Kaya

Abstract Background. We aimed to determine the status of the autonomic nervous system in patients with autosomal-dominant polycystic kidney disease (ADPKD) who were normotensive and had normal renal function. Methods. A total of 28 normotensive ADPKD patients with normal renal function and 30 healthy control subjects consented to participate in the study. Heart rate recovery (HRR) indices were defined as the reduction in heart rate from the rate at peak exercise to the rate at the 1st, 2nd, 3rd and 5th minutes after the cessation of the exercise stress test; these results were indicated HRR1, HRR2, HRR3 and HRR5, respectively. Results. The 1st- and 2nd-minute HRR indices of patients with ADPKD were significantly lower than those of the healthy control group (27.1±7.9 vs 32.0±7.9; p=0.023 and 46.9±11.5 vs 53.0±9.0; p=0.029, respectively). Similarly, HRR indices after the 3rd and 5th minutes of the recovery period were significantly lower in patients with ADPKD when compared with indices in the control group (56.7±12.0 vs 65.1±11.2; p=0.008 and 62.5±13.8 vs 76.6±15.5; p =0.001, respectively). Conclusion. Impaired HRR index is associated with normotensive early-stage ADPKD patients. Increased renal ischemia and activation of the renin–angiotensin–aldosterone system (RAAS) may contribute to impairment in the autonomic nervous system in these patients before the development of hypertension. Even if ADPKD patients are normotensive, there appears to be an association with autonomic dysfunction and polycystic kidney disease.


Journal of Investigative Medicine | 2013

Mean platelet volume and its relation with arterial stiffness in patients with normotensive polycystic kidney disease.

Ozcan Orscelik; Ismail Kocyigit; Mahmut Akpek; Orhan Dogdu; Coskun Kaya; Aydin Unal; Murat Hayri Sipahioglu; Bulent Tokgoz; Halit Zengin; Oktay Oymak; Mehmet Gungor Kaya

Background Autosomal-dominant polycystic kidney disease (ADPKD) demonstrates cardiovascular manifestations, such as hypertension, myocardial infarction, and increased carotid intimae-media thickness. These complications are the main cause of morbidity and mortality in patients with ADPKD. Platelet activation and arterial stiffness are important manifestations that independently predict cardiovascular events. In the present study, we aimed to investigate the relation between arterial stiffness, mean platelet volume (MPV), and highly sensitive C-reactive protein (hs-CRP) in patients with normotensive polycystic kidney disease. Methods We included 30 normotensive subjects with ADPKD with an estimated glomerular filtration rate (eGFR) of 60 mL or more per minute per 1.73 m2, 30 normotensive subjects with ADPKD with eGFR from 30 to 60 mL/min per 1.73 m2, and 30 healthy controls in our study. Pulse wave velocity (PWV), eGFR, spot urine protein-creatinine ratio, MPV, and hs-CRP levels were measured in all participants. In addition, transthoracic echocardiography and ambulatory blood pressure monitoring were performed. Results Age, sex, biochemical markers, eGFR, hemoglobin level, and platelet count were similar in the ADPKD subjects and the controls. There were significant differences in MPV (9.8 ± 0.7, 8.7 ± 0.8, and 8.0 ± 0.5 femtolitre; P < 0.001) and hs-CRP (6.8 ± 3.0, 5.3 ± 2.7, and 2.6 ± 0.52 mg/L; P < 0.001) in the groups. Additionally, PWV values were increased from healthy subjects to ADPKD patients who have decreased eGFR (5.5 ± 1.1, 8.8 ± 1.6, and 10.8 ± 1.2 m/s; P for trend <0.001). There were significant positive correlations between PWV and MPV (r = 0.401; P = 0.002) and hs-CRP (r = 0.343; P = 0.007) in the patients with ADPKD. Additionally, PWV was independently predicted by MPV (β = 0.286; P = 0.007), proteinuria (β = 0.255; P = 0.001), eGFR (β = −0.479; P < 0.001), and hs-CRP (β = 0.379; P < 0.001) in the patients with ADPKD. In addition, eGFR, as a sign of severity of disease, was independently predicted by MPV (β = −0.325; P = 0.003), PWV (β = −0.471; P < 0.001), and hs-CRP (β = −0.269; P = 0.008). Conclusions Our findings suggest that MPV and hs-CRP levels are associated with increased arterial stiffness in patients with early-stage ADPKD and those with late-stage ADPKD. Also, MPV and hs-CRP were independently associated with the severity of ADPKD.


Renal Failure | 2016

Is there any role of epithelial to mesenchymal transition in the pathogenesis of contrast nephropathy

Hayriye Sayarlioglu; Ali Okuyucu; Abdulkerim Bedir; Osman Salis; Eser Yenen; Garip Bekfilavioglu; Coskun Kaya

Abstract Aim: Contrast medium-induced nephropathy is one of the major complications of intravenous contrast medium use. But its pathogenesis is unclear. Epithelial mesenchymal transition (EMT) is defined as the transformation of the primer epithelial cells to mesenchymal cells. EMT in tubular cells might cause tubulointerstitial damage. In this study, we investigated whether or not EMT has a role in radiocontrast-induced nephropathy. Radiocontrast medium might be triggering reversible EMT via serum and glucocorticoid-regulated kinase 1 (SGK 1). We investigated the effect of different concentrations of the contrast agent iopromide on human proximal tubule cell (HK-2) culture by measuring the level of SGK1, snail family zinc finger 1 (SNAIL1), connective tissue growth factor (CTGF), and collagen type I alpha 1 (COL1A1). Methods: We conducted a scratch assay and qPCR. HK-2 cells were cultured in the petri dishes/flasks and starved with serum-free medium. The 40, 20, and 10 mg/mL doses of iopromide were administrated to cells. The scratches were photographed immediately and again at the 20th hour. The levels of gene expression of SGK1, SNAIL1, CTGF, and COL1A1 were measured using the real-time qPCR system at the end of the 24th hour. Results: Iopromide caused the breaking of intercellular connections, the disappearance of the cobblestone appearance of cells, and the migration of cells at the 20th hour in the scratch assay. It also increased the expression of SGK1, SNAIL1, CTGF, and COL1A1 genes. Conclusion: Our study concluded that certain important markers of EMT increase in different concentrations of the contrast agent. High osmolality might trigger EMT. The relationship between contrast agent and EMT has not been defined before. Further in vivo and in vitro studies are required.


Renal Failure | 2015

Association between colchicine resistance and vitamin D in familial Mediterranean fever.

Ismail Ozer; Türkan Mete; Ozlem Turkeli Sezer; Guyem Kolbasi Ozgen; Gultekin Ozan Kucuk; Coskun Kaya; Elif Kilic Kan; Gulhan Duman; Hacer Pinar Ozturk Kurt

Abstract Although colchicines are the only effective treatment of familial Mediterranean fever (FMF), resistance to colchicines (CR) which is observed in up to 30% of the patients is still a problem. Clinically, resistance to colchicine is defined as three or more attacks within the last 6 months period while using ≥2 mg/day colchicine. Previous studies have shown decreased vitamin D levels in FMF patients compared with healthy controls. The aim of this study is to evaluate whether vitamin D levels differ between CR and non-CR FMF patients. This study included 64 FMF patients who were being followed in Nephrology Clinic of Samsun Research and Education Hospital for at least 1 year. FMF was diagnosed according to the criteria defined by Livneh et al. Serum 25-hydroxy vitamin D (25-OHD) concentration (ng/mL) was detected in all FMF patients who were not in an acute attack period. From 64 patients 29 were accepted as CR. Mean 25-OHD level was 9.39 ± 1.00 ng/mL in CR patients and 18.48 ± 1.09 ng/mL in colchicine responsive patients (p < 0.001). Plasma vitamin D levels were significantly lower in colchicine resistant patients. Vitamin D deficiency may be a factor in etiopathogenesis of CR. Studies in larger patient samples that particularly evaluate the response to vitamin D replacement in CR FMF patients are needed.


Journal of Experimental & Clinical Medicine | 2012

Hipertansiyon hastalarında bitkisel ürün kullanımı

Cem Bicen; Özde Elver; Emre Erdem; Coskun Kaya; Ahmet Karataş; Melda Dilek; Tekin Akpolat

Gunumuzde hastaliklarin tani ve tedavisinde saglanan gelismelere ragmen, kronik hastaliga sahip bireyler, bitkisel urunleri daha sik kullanmaktadirlar. Calismamizin amaci bolgemizde hipertansiyon hastalarinin bitkisel urun kullanim oranini, kullanilan urunleri, bilgi kaynaklarini, doktorlarina bu konuda bilgi verip vermediklerini, kullanilan urunlerin maliyetini arastirmaktir. Arastirma, poliklinigimize kontrole gelen 100 hipertansiyon hastasi ile yapilmistir. Hastalarla ilgili veriler 9 sorudan olusan bir anket formu kullanilarak toplanmistir. Calismamizda hipertansiyon hastalarinda bitkisel urun kulanim oraninin % 53 oldugunu saptadik. En sik kullanilan bitkisel urunler limon ve sarimsakti. Hastalarin buyuk bir kismi (% 83) kullandigi bitkisel urun hakkinda bilgi kaynagini komsu, akraba, arkadas ya da televizyon, radyo olarak belirtmisti. Hastalarin % 28’i urunu hergun duzenli olarak alirken, % 34’u sadece kan basinclari yukseldigi zaman bitkisel urun kullaniyorlardi. Urun kullanan hastalarin 46’si (% 87) ise kullandigi bitkisel urun hakkinda doktoruna bilgi vermemisti. Hastalarin % 87’si kullandiklari urunun maliyetinin aylik 50 TL’nin altinda oldugunu belirttiler. Hipertansiyon hastalarinin onemli bir kismi bitkisel urun kullanmaktadir ve bu konuda doktorlarina bilgi vermemektedirler. Hastalarin bitkisel urunlerin etkilerini ve yan etkilerini bilmeden kullanmalari istenmeyen sonuclara yol acabilir. Herbal product use in hypertension patients Despite recent developments in diagnosis and treatment of diseases, individuals with chronic disease use herbal products much more than others. Our study aims to examine the rates of herbal product use, the kinds of used products, source of information, whether the doctors are being informed and cost of the products used in patients with hypertension in our region. The study has been performed with 100 hypertension patients referred to our outpatient clinic. A questionnaire consisted of 9 questions has been used to gather the data about the patients. In our study, the herbal product use in hypertension patients was 53% . The most frequently used herbal products were lemon and garlic. Majority of the patients (83%) reported the source of information about the product as neighbours, relatives, friends or television and radio. While 28% of the patients were using the herbal product regularly everyday, 34% of them were only using these products if their blood pressure increased. Fourty six (87%) patients used these products did not give information to the clinician about the product. Eighty seven per cent of the patients told that the monthly cost of the product they used was less than 50 TL. A significant proportion of the patients with hypertension uses herbal product and they do not give information to the clinicians about the subject. The use of these kind of products without knowing the effects and side-effects may cause undesirable results. J. Exp. Clin. Med., 2012; 29:109-112


Clinical Rheumatology | 2012

Renal transplantation in patients with familial Mediterranean fever

Emre Erdem; Ahmet Karataş; Coskun Kaya; Melda Dilek; Yarkin Kamil Yakupoglu; Nurol Arık; Tekin Akpolat

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Emre Erdem

Ondokuz Mayıs University

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Melda Dilek

Ondokuz Mayıs University

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Ahmet Karataş

Ondokuz Mayıs University

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Kuddusi Cengiz

Ondokuz Mayıs University

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Nurol Arık

Ondokuz Mayıs University

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