Clinical and experimental studies show that epilepsy affects cardiac function; however, the underlying molecular mechanism has not been fully elucidated. Inwardly-rectifying potassium (Kir) channels transport K+ ions into excitable cells such as neurons and cardiomyocytes; they control the cell excitability by acting towards the repolarization phase of cardiac action potential. Kir channel expression has been previously shown to vary in epileptic brains, at the same time seizures are known to affect the autonomic nervous system. Kir channel expression in cardiac tissue is a possible mechanism for the explanation of cardiac pathology in epilepsy. We investigate the expression of Kir channels in epileptic cardiac tissue by using pentylenetetrazole (PTZ)-kindling model in rats. Our molecular analyses showed significant decrease in cardiac Kir channel mRNA and protein expression of PTZ-kindled rats. Interestingly, both Kir2.x, which directs IK1 flux in ventricular tissue and Kir3.x, which is responsible for IKACh in the atria, were observed to decrease significantly. Kir channel expression also differs between females and males. This is the first study to our knowledge in epileptic cardiac tissue showing the expression of Kir channels. Our results show that Kir channels may play a role in cardiac pathology associated with epilepsy.
BackgroundTelomeres are protective caps consisted of specific tandem repeats (5′-TTAGGG-3′). Shortening of telomeres at each cell division is known as “mitotic clock” of the cells, which renders telomeres as important regulators of lifespan. TRF2 is one of the critical members of shelterin complex, which is a protein complex responsible from the preservation of cap structure, and loss or mutation of TRF2 results in DNA damage, senescence or apoptosis. Since cancer is frequently associated with aberrant cell cycle progression, defective DNA repair or apoptosis pathways, TRF2 could be one likely candidate for cancer therapy.Here we investigated the prognostic role of TRF2 levels in cervical cancer patients. Fold-induction rates were evaluated with respect to median values after real-time PCR analysis. Overall survival, distant disease-free and local recurrence-free survival rates were calculated using Kaplan-Meier long rank test.ResultsBoth five year overall- and disease-free survival rates were longer in patients with higher TRF2 expression compared to lower expression, but results were not statistically significant (69.2% vs 28.9%, respectively). Mean local recurrence-free survivals (LRF) were very close ( 58.6, CI: 44.3-72.9 vs 54.5, CI: 32.1-76.9 months) for high and low expressions, respectively. Cumulative proportion of LRF at the end of five year period was 76.9% for high and 57.1% for low TRF2 expression (P = 0.75). Statistically significant difference was found between survival ratios and Bcl-xL and p53 gene expressions, but not with TRF2. A respectable correlation between TRF2 expression and apoptosis along with distant metastasis was noted (P = 0.045 and 0.036, respectively). Additionally, high TRF2 expression levels had a positive impact in five year survival rate of stage IIIB-IVA patients (P = 0.04).ConclusionsOur results support the role of TRF2 in apoptosis and imply a positive relation with distant metastases and survival in advanced stage patients. The remarkable difference in survival periods of patients with different TRF2 expressions suggest that TRF2 may be a candidate factor to estimate survival for cervical cancer, a preliminary observation which should further be verified with a larger cohort.
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