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Dive into the research topics where Cem Haymana is active.

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Featured researches published by Cem Haymana.


European Journal of Endocrinology | 2011

Metabolic syndrome and the effect of testosterone treatment in young men with congenital hypogonadotropic hypogonadism

Alper Sonmez; Cem Haymana; Erol Bolu; Aydogan Aydogdu; Serkan Tapan; Muhittin Serdar; Battal Altun; Cem Barcin; Abdullah Taslipinar; Coskun Meric; Gokhan Uckaya; Mustafa Kutlu

OBJECTIVE The relationship between metabolic syndrome (MS) and hypogonadism has always been investigated in study groups confounded with aging, obesity or chronic metabolic disorders. So far, there has been no data about the presence of MS in young hypogonadal patients. Also, there is controversial data about the metabolic effects of testosterone replacement therapy. We investigated the frequency of MS in treatment-naïve, young men with congenital hypogonadal hypogonadism (CHH). We also searched for the effect of testosterone replacement on the metabolic profiles of this specific patient group. DESIGN Retrospective analysis. METHODS A total of 332 patients (age 21.68 ± 2.09 years) were enrolled. The control group included 395 age- and body mass index (BMI)-matched healthy young men (age 21.39 ± 1.49 years). Standard regimen of testosterone esters (250 mg/3 weeks) was given to 208 patients. RESULTS MS was more prevalent in CHH (P<0.001) according to healthy controls. The patients had higher arterial blood pressure, waist circumference (WC), triglyceride (P<0.001 for all), fasting glucose (P=0.02), fasting insulin (P=0.004), homeostatic model assessment of insulin resistance (HOMA-IR) (P=0.002) and lower high density lipoprotein (HDL) cholesterol (P<0.001) levels. After 5.63±2.6 months of testosterone treatment, the BMI, WC (P<0.001 for both), systolic blood pressure (P=0.002) and triglyceride level (P=0.04) were increased and the total and HDL cholesterol levels were decreased (P=0.02 and P<0.001 respectively). CONCLUSIONS This study shows increased prevalence of MS and unfavorable effects of testosterone replacement in young patients with CHH. Long-term follow-up studies are warranted to investigate the cardiovascular safety of testosterone treatment in this specific population.


Metabolism-clinical and Experimental | 2010

Plasma apelin levels in subjects with nonalcoholic fatty liver disease

Cemal Nuri Ercin; Teoman Dogru; Serkan Tapan; Muammer Kara; Cem Haymana; Nuri Karadurmus; Yildirim Karslioglu; Cengizhan Acıkel

Nonalcoholic fatty liver disease (NAFLD), one of the most common forms of chronic liver disease, is closely associated with obesity and insulin resistance. Recent studies suggest that apelin, a newly described adipokine, is associated with hyperinsulinemia and inflammation. The aim of the study was to investigate plasma apelin concentrations in biopsy-proven NAFLD patients who had no metabolic confounders and also to search for the association of apelin with adiponectin, body mass index (BMI), and insulin sensitivity. Fifty male patients with NAFLD and 30 healthy male controls were enrolled. Apelin was measured along with BMI, lipids, glucose, insulin, adiponectin, and homeostasis model assessment (HOMA) of insulin resistance indexes. Plasma apelin levels were significantly higher and adiponectin levels were lower in NAFLD patients when compared with the controls (P < .001 and P = .013, respectively). In multivariate analysis adjusted for BMI and HOMA indexes, the differences in apelin and adiponectin disappeared in the 2 groups (P = .3 and P = .1, respectively). In addition, apelin levels were positively correlated with BMI (r = 0.29, P = .05) and HOMA indexes (r = 0.4, P = .008) in subjects with NAFLD. The results of this preliminary study suggest that plasma apelin levels are not altered in nondiabetic and normotensive male subjects with NAFLD.


Clinical Endocrinology | 2013

Effects of three different medications on metabolic parameters and testicular volume in patients with hypogonadotropic hypogonadism: 3‐year experience

Aydogan Aydogdu; Erol Bolu; Alper Sonmez; Ilker Tasci; Cem Haymana; Ramazan Acar; Coskun Meric; Abdullah Taslipinar; Taner Ozgurtas; Omer Azal

The aim of this study was to demonstrate the influences of three different treatment strategies on biochemical parameters and testicular volume (TV) in patients with idiopathic hypogonadotropic hypogonadism (IHH).


Hormone and Metabolic Research | 2014

Osteoprotegerin, Fibroblast Growth Factor 23, and Vitamin D3 Levels in Male Patients with Hypogonadism

Coskun Meric; Alper Sonmez; Aydogan Aydogdu; Serkan Tapan; Cem Haymana; Yalcin Basaran; K. Baskoy; E. Sertoglu; Abdullah Taslipinar; E. Bolu; Omer Azal

Cardiometabolic disorders and osteoporosis are prevalent in patients with hypogonadism. Osteoprotegerin (OPG) and fibroblast growth factor-23 (FGF-23), are co-secreted from bones and vascular endothelium, regulating bone mineral metabolism and vascular functions. Vitamin D is another hormone with dual effects on bone and vascular metabolism. The aim of this study was to search for any difference between the serum levels of OPG, FGF-23, and vitamin D in patients with hypogonadism and the healthy controls. We also aimed to search for any relationship between these parameters and endothelial dysfunction or insulin resistance. Forty-nine male patients with congenital hypogonadotropic hypogonadism (CHH) (mean age 20.71 ± 1.75 years) and 43 BMI matched healthy male subjects (mean age 21.37 ± 1.04 years) were enrolled. OPG, FGF-23, vitamin D, and asymmetric dimethylarginine (ADMA) levels were measured from the fasting serum samples. The insulin sensitivity was estimated by homeostatic model assessment-insulin resistance (HOMA-IR) formula. Triglycerides, insulin, HOMA-IR, and ADMA levels in the patient group were significantly higher than the values of the control group (p = 0.014, p = 0.002, p = 0.003, p < 0.001, respectively). The OPG, FGF-23, and vitamin D levels of the patients were not significantly different from the healthy controls. In addition, these markers were not correlated to ADMA or HOMA-IR levels. The results show that young and treatment naive subjects with CHH have endothelial dysfunction and insulin resistance when compared to their healthy counterparts. However, the OPG, FGF-23, and vitamin D levels were similar in the 2 groups. In addition, these parameters are not significantly related to the endothelial functions or insulin resistance in these subjects.


Endocrine Journal | 2015

Endothelial dysfunction, insulin resistance and inflammation in congenital hypogonadism, and the effect of testosterone replacement

Alper Sonmez; Cem Haymana; Aydogan Aydogdu; Serkan Tapan; Yalcin Basaran; Coskun Meric; Kamil Baskoy; Mustafa Dinc; Mahmut Yazici; Abdullah Taslipinar; Cem Barcin; Mahmut Ilker Yilmaz; Erol Bolu; Omer Azal

Patients with hypogonadism have poor cardiovascular and metabolic outcomes, and the effect of testosterone replacement therapy (TRT) is not clear. We investigated the presence of inflammation, insulin resistance and endothelial dysfunction in an unconfounded population of congenital hypogonadotrophic hypogonadism (CHH) and the effect of TRT on these subjects. A total of 60 patients with CHH (mean age 21.82±2.22 years) and 70 healthy control subjects (mean age 21.32±1.13 years) were enrolled. The demographic parameters, Asymmetric dimethylarginine (ADMA), TNF-like weak inducer of apoptosis (TWEAK), high sensitive C reactive protein (hs-CRP) and homeostatic model assessment of insulin resistance (HOMA-IR) levels were measured before and after TRT. The patients had higher Waist Circumferences (WC) (p=0.009), Diastolic Blood Pressures (p=0.02), Triglycerides (p=0.03), ADMA, insulin and HOMA-IR levels (p<0.001 for all) and lower TWEAK levels (p<0.001), compared to the healthy controls. After 5.56 ± 2.04 months of TRT, the patients had significantly elevated systolic blood pressures (p=0.01), body mass indexes and WC (p<0.001 and p=0.001 respectively) and decreased total and HDL cholesterol levels (p=0.032 and p<0.001 respectively). ADMA levels significantly increased (p=0.003), while the alterations in TWEAK, hsCRP and HOMA-IR were not significant. The results of the present study show that endothelial dysfunction, inflammation and insulin resistance are prevalent even in the very young subjects with CHH, who have no metabolic or cardiac problems at present. This increased cardiometabolic risk however, do not improve but even get worse after six months of TRT. Long term follow-up studies are warranted to investigate the unfavorable cardiometabolic effects of TRT.


Endokrynologia Polska | 2017

Effect of testosterone replacement therapy on vitamin D and FGF-23 levels in congenital hypogonadism

Cem Haymana; Alper Sonmez; Aydogan Aydogdu; Serkan Tapan; Yalcin Basaran; Coskun Meric; Kamil Baskoy; Abdullah Taslipinar; Mahmut Ilker Yilmaz; Omer Azal

INTRODUCTION Patients with hypogonadism are at increased risk of cardiac and metabolic diseases and osteoporosis. Vitamin D and Fibroblast growth factor-23 (FGF-23) play role in the regulation of bone mineral metabolism and endothelial functions. Low vitamin D levels are reported in hypogonadism, while there is no data about the effect of testosterone replacement therapy (TRT). We investigated the effect of TRT on vitamin D and FGF-23 levels along with endothelial functions and insulin resistance in hypogonadal patients. MATERIAL AND METHODS Patients with congenital hypogonadotrophic hypogonadism (CHH) (n=32, age 20.6 ±1.58 years) were enrolled. TRT was implemented in transdermal form. The demographic parameters, FGF-23, 25(OH)D3, Asymmetric dimethylarginine (ADMA) and homeostatic model assessment of insulin resistance (HOMA-IR) levels were measured both before and after TRT. RESULTS After a follow-up period of 3.63±1.33 months, ADMA and FGF-23 levels were significantly increased (p=0.03 and p=0.005 respectively), while the 25(OH)D3 and HOMA-IR index were not significantly changed. The body mass index and waist circumference levels of the patients were also increased (p<0.001 and p=0.02) along with a significant decrease in the HDL cholesterol levels (p=0.006). CONCLUSIONS The results show that a short term TRT increases plasma FGF-23 and ADMA levels, in young, treatment naive patients with CHH. Whether this is an early implication of TRT related adverse effects in this very young and treatment naïve population of CHH is not clear. Future prospective studies are required to find out the long-term effects of TRT on cardio-metabolic morbidity and mortality in this specific population.


Toxicology Mechanisms and Methods | 2017

Oxidative stress status in congenital hypogonadism: an appraisal

Cem Haymana; Aydogan Aydogdu; B. Soykut; Onur Erdem; T. Ibrahimov; Mustafa Dinc; Coskun Meric; Yalcin Basaran; Alper Sonmez; Omer Azal

Abstract Patients with hypogonadism are at increased risk of cardiac and metabolic diseases. However, the pathogenesis of increased cardiometabolic risk in patients with hypogonadism is not clear. Oxidative stress plays an important role in the pathogenesis of cardiometabolic diseases. This study aimed to investigate possible differences in oxidative stress conditions between patients with hypogonadism and healthy controls. In this study, 38 male patients with congenital hypogonadotropic hypogonadism (CHH) (mean age: 21.7 ± 1.6 years) and 44 healthy male controls (mean age: 22.3 ± 1.4 years) with almost equal body mass index were enrolled. The demographic parameters, follicle-stimulating hormone (FSH), luteinizing hormone (LH), total and free testosterone, homeostatic model assessment of insulin resistance (HOMA-IR) and oxidative stress parameters, such as superoxide dismutase, catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA), were compared between both groups. Compared to the healthy controls, triglycerides (p = .02), insulin levels, HOMA-IR values, CAT activities and MDA levels (p < .001 for all) were significantly higher and HDL cholesterol (p = .04), total and free testosterone, FSH, LH levels and GPx activity were significantly lower (p < .001 for all) in patients with CHH. There were significant correlations between total testosterone levels and CAT activity (r = −.33 p = .01), GPx activity (r = .36 p = .007) and MDA (r = −.47 p < .001) levels. The results of this study showed that young and treatment-naïve patients with congenital hypogonadism had an increased status of oxidative stress.


Experimental and Clinical Endocrinology & Diabetes | 2017

Add on Exenatide Treatment is Beneficial in Poorly Controlled Obese Type 2 Diabetics under Intensive Insulin Regimens.

Alper Sonmez; Mustafa Dinc; Abdullah Taslipinar; Aydogan Aydogdu; Coskun Meric; Yalcin Basaran; Cem Haymana; Orhan Demir; Ilker Yilmaz; Omer Azal

Background: Intensive insulin treatment is bothersome in obese patients with type 2 diabetes mellitus. High insulin dosages further increase weight gain and the risk of hypoglycemia. Glucagon like peptide-1 receptor agonists decrease the insulin need, cause weight loss and reduce the risk of hypoglycemia. There is limited data about the effect of exenatide on obese diabetics under intensive insulin regimens. Methods: This retrospective case series report the clinical outcomes of 23 obese (13 morbidly obese) patients with uncontrolled type 2 diabetes mellitus (Age=59±10.44 years, body mass index 41.1±6.8 kg/m2, HbA1c 9.9±1.5%), under high dose (94.1±39.6 unit) intensive insulin. Exenatide twice daily was added for a mean follow-up period of 11.22±7.01 (3-30) months. Intensive insulin regimens were continued in 7 patients while the others were switched to basal insulin during the follow-up. Results: During the follow-up, mean HbA1c levels of the patients significantly improved (p=0.019), along with the significant decrease in body mass index and the total insulin need (p<0.001 for both). Baseline insulin dosages were significantly higher in the intensive regimen group (p=0.013) while other demographical and clinical characteristics were similar. No significant difference was present between the groups regarding the alterations of HbA1c, body mass index and the reduction in total insulin dosages. Conclusion: Add on exenatide appears to be a rational treatment modality in uncontrolled obese patients with type 2 diabetes mellitus despite intensive insulin regimens. Further prospective randomized studies with longer follow-up periods are recommended.


Archives of Endocrinology and Metabolism | 2017

Visceral adiposity index and triglyceride/high-density lipoprotein cholesterol ratio in hypogonadism

Cem Haymana; Alper Sonmez; Aydogan Aydogdu; Serkan Tapan; Yalcin Basaran; Coskun Meric; Kamil Baskoy; Mustafa Dinc; Mahmut Yazici; Abdullah Taslipinar; Cem Barcin; Mahmut Ilker Yilmaz; Erol Bolu; Omer Azal

Background Cardiometabolic risk is high in patients with hypogonadism. Visceral adiposity index (VAI) and triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio are the practical markers of atherosclerosis and insulin resistance and independent predictors of cardiaovascular risk. To date, no study has evaluated VAI levels and TG/HDL-C ratio in hypogonadism. Subjects and methods A total of 112 patients with congenital hypogonadotrophic hypogonadism (CHH) (mean age, 21.7 ± 2.06 years) and 124 healthy subjects (mean age, 21.5 ± 1.27 years) were enrolled. The demographic parameters, VAI, TG/HDL-C ratio, asymmetric dimethylarginine (ADMA), high-sensitivity C-reactive protein (hs-CRP), and homeostatic model assessment of insulin resistance (HOMA-IR) levels were measured for all participants. Results The patients had higher total cholesterol (p = 0.04), waist circumference, triglycerides, insulin, and HOMA-IR levels (p = 0.001 for all) than the healthy subjects. VAI and ADMA and TG/HDL-C levels were also higher in patients than in healthy subjects (p < 0.001 for all). VAI was weakly correlated with ADMA (r = 0.27, p = 0.015), HOMA-IR (r = 0.22, p = 0.006), hs-CRP (r = 0.19, p = 0.04), and total testosterone (r = -0.21, p = 0.009) levels, whereas TG/HDL-C ratio was weakly correlated weakly with ADMA (r = 0.30, p = 0.003), HOMA-IR (r = 0.22, p = 0.006), and total testosterone (r = -0.16, p = 0.03) levels. Neither VAI nor TG/HDL-C ratio determined ADMA, HOMA-IR, and hs-CRP levels. Conclusions The results of this study demonstrate that patients with hypogonadism have elevated VAI and TG/HDL-C ratio. These values are significantly correlated with the surrogate markers of endothelial dysfunction, inflammation, and insulin resistance. However, the predictive roles of VAI and TG/HDL-C ratio are not significant. Prospective follow-up studies are warranted to clarify the role of VAI and TG/HDL-C ratio in predicting cardiometabolic risk in patients with hypogonadism.


Annals of Allergy Asthma & Immunology | 2017

Association of neck circumference and pulmonary function in children

Onur Akın; Mutluay Arslan; Cem Haymana; Erdem Karabulut; Bulent Hacihamdioglu; Suleyman Tolga Yavuz

BACKGROUND Childhood obesity leads to many complications including impaired respiratory function. There are various anthropometric parameters related to obesity. OBJECTIVE To investigate the correlation between anthropometric indices and pulmonary function test results in children without asthma. METHODS Children without any respiratory disorders were enrolled in this study. Anthropometric measurements, such as height, weight, neck circumference (NC), and waist circumference, were obtained from the enrollees and body mass index was calculated. Afterward, pulmonary function tests were performed using spirometry. RESULTS A total of 178 children (106 boys, 59.5%) with a mean age of 9.7 years were included the study. NC was above the 90th percentile in 65 children. Importantly, pulmonary parameters, such as forced expiratory volume during the first second (FEV1) and the ratio of FEV1 to forced vital capacity (FVC), were lower in subjects with a large NC. Similarly, waist circumference was above the 90th percentile in 67 children, and FEV1/FVC was significantly lower in children with a large waist circumference. Moreover, there was a statistically significant negative correlation among FEV1, FEV1/FVC, and body mass index SD score. Also, multivariable linear regression analysis showed that an NC above the 90th percentile was associated with lower FEV1 and FEV1/FVC values. CONCLUSION We identified NC as a novel anthropometric index that is strongly correlated with respiratory functions in children. Therefore, close monitoring of respiratory symptoms, particularly in children with obesity and a large NC, could help with early and prompt determination of respiratory complications of obesity.

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Alper Sonmez

Military Medical Academy

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Omer Azal

Military Medical Academy

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Coskun Meric

Military Medical Academy

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Serkan Tapan

Military Medical Academy

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Mustafa Dinc

Military Medical Academy

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Yalcin Basaran

Military Medical Academy

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Cem Barcin

Military Medical Academy

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Orhan Demir

Military Medical Academy

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