Irem Yilmaz

Bone morphogenetic protein‐2, ‐6, and ‐7 differently regulate osteogenic differentiation of human periodontal ligament stem cells

The utility of adult stem cells for bone regeneration may be an attractive alternative in the treatment of extensive injury, congenital malformations, or diseases causing large bone defects. To create an environment that is supportive of bone formation, signals from molecules such as the bone morphogenetic proteins (BMPs) are required to engineer fully viable and functional bone. We therefore determined whether BMP-2, -6, and -7 differentially regulate the (1) proliferation, (2) mineralization, and (3) mRNA expression of bone/mineralized tissue associated genes of human periodontal ligament stem cells (hPDLSCs), which were obtained from periodontal ligament tissue of human impacted third molars. hPDLSCs from six participants were isolated and characterized using histochemical and immunohistochemical methods. A real-time cell analyzer was used to evaluate the effects of BMP-2, -6, and -7 on the proliferation of hPDLSCs. hPDLSCs were treated with Dulbeccos modified Eagles medium containing different concentrations of BMP-2, -6, and -7 (10, 25, 50, 100 ng/mL) and monitored for 264 hours. After dose-response experiments, 50 and 100 ng/mL concentrations of BMPs were used to measure bone/mineralized tissue-associated gene expression. Type I collagen, bone sialoprotein, osteocalcin, osteopontin, and osteoblastic transcription factor Runx2 mRNA expression of hPDLSCs treated with BMP-2, -6, and -7, were evaluated using quantitative RT-PCR. Biomineralization of hPDLSCs was assessed using von Kossa staining. This study demonstrated that BMPs at various concentrations differently regulate the proliferation, mineralization, and mRNA expression of bone/mineralized tissue associated genes in hPDLSCs. BMPs regulate hPDLSC proliferation in a time and dose-dependent manner when compared to an untreated control group. BMPs induced bone/mineralized tissue-associated gene mRNA expression and biomineralization of hPDLSCs. The most pronounced induction occurred in the BMP-6 group in the biomineralization of the hPDLSCs. Our data suggest that BMP-2, -6, and -7 are potent regulators of hPDLSC gene expression and biomineralization. Employing BMPs with hPDLSCs isolated from periodontal ligament tissues provides a promising strategy for bone tissue engineering.

Associations Between Neutrophil Gelatinase Associated Lipocalin, Neutrophil-to-Lymphocyte Ratio, Atrial Fibrillation and Renal Dysfunction in Chronic Heart Failure

Background Atrial fibrillation (AF) and renal dysfunction are two common comorbidities in patients with chronic heart failure with reduced ejection fraction (HFrEF). This study evaluated the effect of permanent AF on renal function in HFrEF and investigated the associations of atrial fibrillation, neutrophil gelatinase-associated lipocalin (NGAL), and neutrophil-to-lymphocyte ratio (NLR) with adverse clinical outcome. Material/Methods Serum NGAL levels measured by ELISA and NLR were compared between patients with sinus rhythm (HFrEF-SR, n=68), with permanent AF (HFrEF-AF, n=62), and a healthy control group (n=50). Results Mean eGFR levels were significantly lower, and NLR and NGAL levels were significantly higher in the HFrEF patients than in the control patients but the difference between HFrEF-SR and HFrEF-AF was not statistically significant (NGAL: 95 ng/mL in HFrEF-SR, 113 ng/mL in HFrEF-AF and 84 ng/mL in the control group; p<0.001). Independent associates of baseline eGFR were age, hemoglobin, NLR, triiodothyronine, and pulmonary artery systolic pressure. In a mean 16 months follow-up, adverse clinical outcome defined as progression of kidney dysfunction and composite of all-cause mortality and re-hospitalization were not different between HFrEF-SR and HFrEF-AF patients. Although NGAL was associated with clinical endpoints in the univariate analysis, Cox regression analysis showed that independent predictors of increased events were the presence of signs right heart failure, C-reactive protein, NLR, triiodothyronine, and hemoglobin. In ROC analysis, a NLR >3 had a 68% sensitivity and 75% specificity to predict progression of kidney disease (AUC=0.72, 95% CI 0.58–0.85, p=0.001). Conclusions Presence of AF in patients with HFrEF was not an independent contributor of adverse clinical outcome (i.e., all-cause death, re-hospitalization) or progression of renal dysfunction. Renal dysfunction in HFrEF was associated with both NLR and NGAL levels, but systemic inflammation reflected by NLR seemed to be a more important determinant of progression of kidney dysfunction.

Differentiation Potential of Mouse Embryonic Stem Cells into Insulin Producing Cells in Pancreatic Islet Microenvironment.

BACKGROUND The differentiation capacity of embryonic stem cells (ESCs) has great promise for type-1 diabetes for cellular treatment. Therefore, different strategies have been reported so far for derivation of insulin producing cells (IPCs) from ESCs. Providing similar microenvironmental conditions as in vivo, functional differentiation of stem cells into desired cell types could be obtained in vitro. The aim of the present research was to utilize differentiation potential of ESCs to IPCs by co-culture with mouse pancreatic islets (mPIs) for the first time. METHODS We present an in-direct differentiation protocol which compared with a conventional differentiation protocol. Novel in-direct co-culture differentiation protocol in which mPIs induced differentiation of ESCs into IPCs was used. This technique was compared with the chemical differentiation protocol that involved supplementing the differentiation media with specific growth factors. We analyzed differentiated cells in both groups by immune labelling, gene expression and protein secretion. RESULTS IPCs were obtained with in-direct co-culture within 30 days. Differentiated ESCs were found to be positive for IPC specific markers, Pdx1, Insulin, C-peptide, Glut2 and MafA. The results of immunocytochemical and gene expression analysis showed higher differentiation efficiency in co-culture group than chemical differentiation group. These results were confirmed by the response assay to high glucose levels with ELISA for insulin. DISCUSSION Our findings illustrate the significant effect of co-culture in different stages of differentiation and maturation of ESCs in vitro. We have developed an efficient and easy way to differentiate ESCs into IPCs, which possess similar characters of mature insulin positive cells.

Could decreased vitamin D levels be related with impaired cardiac autonomic functions in patients with chronic heart failure: an observational study.

OBJECTIVE Vitamin D status has been implicated in the pathophysiology of heart failure (HF). The aim of this study was to investigate the association between vitamin D levels with heart rate variability and heart rate turbulence in patients with heart failure whom had ischemic and non-ischemic dilated cardiomyopathy. METHODS Study designed as an observational cross-sectional study. Seventy-one patients [36 non-ischemic dilated cardiomyopathy (NIDCM), 35 ischemic dilated cardiomyopathy (IDCM)] with chronic heart failure and 25 control subject were included. It was evaluated the association between 25 hydroxyvitamin D [25(OH)D] and calcitriol levels with heart rate variability time domain (SDNN, SDANN, RMSSD) and heart rate turbulence [turbulence onset (TO), turbulence slope (TS)] parameters. Statistical analysis was performed using Kruskal-Wallis test and ANOVA. RESULTS Calcitriol levels in NIDCM patients with abnormal TO and TS were significantly lower than NIDCM patients with normal TO (17.1 ± 11.3 vs. 27.6 ± 15.5 pg/mL, p=0.05) and TS (16.6 ± 9.1 vs. 29.4 ± 16.9 pg/mL, p=.018). There was a positive correlation between 25 (OH) D with heart rate variability parameters SDNN (r=0.368, p=0.027) and SDANN (r=0.360, p=0.031). It was not found any association between vitamin D and parameters of heart rate variability and heart rate turbulence in IDCM patients. CONCLUSION Insufficiency of vitamin D may have deleterious effects on cardiac autonomic functions which were showed with heart rate turbulence and heart rate variability in patients with NIDCM. Vitamin D levels might be a predictor to determine the sudden cardiac death in patients with non-ischemic etiology.

Clinical ventricular tachycardia and surgical epicardial ICD implantation in a patient with a Fontan operation for double-inlet left ventricle : online article - case report

The Fontan operation is the primary surgical technique used for palliation of patients with single-ventricle physiology. Arrhythmias are frequently observed and associated with morbidity and mortality in Fontan patients. The frequency of arrhythmias after the Fontan procedure increases over time and it was reported to reach 50% in a 20-year follow up. Atrial tachyarrhythmias, especially atrial tachycardia and sinus bradycardia, are most frequently observed in these patients. Ventricular arrhythmias are rarely observed. Generally, medical therapy, catheter ablation, pacemaker or implantable cardioverter defibrillator (ICD) implantation are options in the treatment of these arrhythmias. It may be difficult to implant either a pacemaker or an ICD in patients on whom the Fontan procedure has been performed. In conditions where access to the right ventricle is from the venous system, it is anatomically impossible. Where there is no functional right ventricle, device implantation can be performed with alternative methods other than the conventional transvenous approach. In this report, we discuss a middle-aged woman with a Fontan operation performed 14 years earlier, who presented with ventricular tachycardia (VT) and in whom an epicardial ICD was implanted. The literature on this issue is also reviewed.

What is the Lowest Value of Left Ventricular Baseline Ejection Fraction that Predicts Response to Cardiac Resynchronization Therapy

Background Cardiac resynchronization therapy (CRT) is an effective treatment option for patients with refractory heart failure. However, many patients do not respond to therapy. Although it has been thought that there was no relation between response to CRT and baseline ejection fraction (EF), the response rate of patients with different baseline LVEF to CRT has not been evaluated in severe left ventricular systolic dysfunction. We aimed to investigate any difference in response to CRT between the severe heart failure patients with different baseline LVEF. Material/Methods In this study, 141 consecutive patients (mean age 59±13 years; 89 men) with severe heart failure and complete LBBB were included. Patients were divided into 3 groups according to their baseline LVEF: 5–15%, Group 1; 15–25%, Group 2, and 25–35%, Group 3. NYHA functional class, LVEF, LV volumes, and diameters were assessed at baseline and after 6 months of CRT. A response to CRT was defined as a decrease in LVSVi (left ventricular end-systolic volume index) ≥10% on echocardiography at 6 months. Results After 6 months, a significant increase of EF and a significant decrease of LVESVi and LVEDVi after 6 months of CRT were observed in all groups. Although the magnitude of improvement in EF was biggest in the first group, the percentage of decrease in LVESVi and LVEDVi was similar between the groups. The improvement in NYHA functional class was similar in all EF subgroups. At 6-month follow-up, 100 (71%) patients showed a reduction of >10% in LVESVi (mean reduction: −15.5±26.1 ml/m2) and were therefore classified as responders to CRT. Response rate to CRT was similar in all groups. It was 67%, 75%, and 70% in Group 1, 2, and 3, respectively, at 6-month follow-up (p>0.05). There was no statistically significant relation between the response rate to CRT and baseline LVEF, showing that the CRT has beneficial effects even in patients with very low LVEF. Conclusions It seems there is no lower limit for baseline LVEF to predict non-response to CRT in eligible patients according to current guidelines.

Quadricuspid Aortic Valve Visualized by Three-Dimensional Transthoracic Echocardiography

Quadricuspid aortic valve is a rare congenital anomaly that may cause aortic regurgitation. A 77-year-old male patient was referred to our clinic with complaints of stable angina pectoris. We report a case of a quadricuspid aortic valve diagnosed by 3-dimentional transthoracic echocardiography.

Improvement in left ventricular intrinsic dyssynchrony with cardiac resynchronization therapy

Objective: Cardiac resynchronization therapy (CRT) has been shown to induce a structural and electrical remodeling; the data on whether left ventricle (LV) reverse remodeling is associated with restitution of intrinsic contraction pattern are unknown. In this study, we investigated the presence of improvement in left ventricular intrinsic dyssynchrony in patients with CRT. Methods: A total of 45 CRT recipients were prospectively studied. Dyssynchrony indexes including interventricular mechanical delay (IVMD) and tissue Doppler velocity opposing-wall delay (OWD) as well as QRS duration on 12-lead surface electrocardiogram were recorded before CRT device implantation. After 1 year, patients with chronic biventricular pacing were reprogramed to VVI 40 to allow the resumption of native conduction and contraction pattern. After 4–6 h of intrinsic rhythm, QRS duration and all echocardiographic measurements were recorded. Dyssynchrony was defined as IVMD >40 ms and OWD >65 ms. CRT response was defined by a ≥15% reduction in left ventricular end-systolic volume (LVESV) at a 12-month follow-up. Results: Thirty-two patients (71%) showed response to CRT. The native QRS duration reduced significantly from 150±12 ms to 138±14 ms (p<0.001), and dyssynchrony indexes showed a significant improvement only in responders. The mean OWD reduced from 86±37 ms to 50±29 ms (p<0.001), and the mean IVMD decreased from 55±22 ms to 28±22 ms (p<0.001) in responders. The reduction in LVESV was significantly correlated with ΔOWD (r=0.47, p=0.001), ΔIVMD (r=0.45, p=0.001), and ΔQRS (r=0.34, p=0.022). Conclusion: Chronic CRT significantly improves LV native contraction pattern and causes reverse remodeling in dyssynchrony.

The Better Outcomes Associated with Warfarin use in Patients with Heart Failure in Either Atrial Fibrillation or Sinus Rhythm

PP-051 Warfarin use and associated outcomes in patients with chronic heart failure (HF) have not been well described previously. We hypothesized that warfarin is associated with lower risks of cardiovascular mortality in patients with sinus rhythm, atrial fibrillation and pacemaker rhythm. We

A Turkish Perspective on Coronary Artery Bypass Surgery and Percutaneous Coronary Artery Intervention in Chronic Heart Failure Patients

The impact of coronary revascularization methods (coronary artery bypass graft [CABG] surgery and stent implantation) on clinical outcome has not been determined yet in patients with systolic heart failure (SHF). We examined outcomes in patients discharged from our hospital after hospitalization for decompensated SHF. Of 637 patients with SHF (mean age, 64 ± 13 years; mean ejection fraction, 26.5% ± 9%), 402 patients (63%) had coronary artery disease (CAD) and 235 patients (37%) had no CAD; 223 patients (35%) died because of cardiovascular reasons during follow-up. Patients who had stenting alone and patients who had CABG surgery and stenting had better prognosis than patients with CAD but no revascularization procedure (P < .001 and P = .013, respectively). In the patients with SHF having CAD who had stenting and CABG surgery + stenting may have better prognosis compared with patients with CAD who had no revascularization procedure in their past.