Evaluation of telomere length and telomerase activity on predicting in vitro fertilization treatment outcomes.

The current article is a literature review aiming to provide an overview of the existing knowledge on the association between telomere length and telomerase activity and in vitro fertilization. Recently, telomeres have been used as an effective biomarker to determine biological age, which may differ from chronological age due to genetic, lifestyle, and environmental factors. Cellular senescence, along with other exogenous and mainly environmental factors, can enhance telomere wear, further shortening their ends and may also affect reproductive aging. IVF is a common fertility treatment caused by female reasons (age, ovulation disorders, damaged or blocked fallopian tubes, endometriosis), male reasons (low sperm quantity or quality), or unexplained infertility. A growing number of studies have proposed a relationship between telomere length and telomerase activity and IVF success and have suggested their use as candidate biomarkers for IVF outcome. Nevertheless, additional studies are necessary to be conducted, in order to clarify the possible implication of telomeres in IVF and to evaluate their possible role as valuable predictors of IVF result.

Boehmeria Nivea Extract (BNE-RRC) Reverses Epithelial-Mesenchymal Transition and Inhibits Anchorage-Independent Growth in Tumor Cells.

The epithelial-mesenchymal transition (EMT) phenotype, identified as a significant clinical indicator in regard to cancer, manifests as a biological process wherein cells transition from having epithelial to mesenchymal characteristics. Physiologically, EMT plays a crucial role in tissue remodeling, promoting healing, repair, and responses to various types of tissue damage. This study investigated the impact of BNE-RRC on oral cancer cells (KB) and revealed its significant effects on cancer cell growth, migration, invasion, and the EMT. BNE-RRC induces the epithelial-like morphology in KB cells, effectively reversing the EMT to a mesenchymal-epithelial transition (MET). Extraordinarily, sustained culturing of cancer cells with BNE-RRC for 14 days maintains an epithelial status even after treatment withdrawal, suggesting that BNE-RRC is a potential therapeutic agent for cancer. These findings highlight the promise of BNE-RRC as a comprehensive therapeutic agent for cancer treatment that acts by inhibiting cancer cell growth, migration, and invasion while also orchestrating a reversal of the EMT process. In this study, we propose that BNE-RRC could be an effective agent for cancer treatment.

Telomerase activity and hTERT gene expression in patients with acute coronary syndrome and stable coronary artery disease.

BACKGROUND: In this study, we aimed to examine the telomerase activity and hTERT gene expression in patients with acute coronary syndrome (ACS) and those with stable coronary artery disease (SCAD) and compare the results to controls. Additionally, we compared overall mortality rates relative to the telomerase activity. METHODS: A total of 211 patients (78 ACS and 71 SCAD patients) were included in the study. The telomerase concentration was measured by ELISA and used to determine telomerase activity. The hTERT gene expression was determined by real-time PCR. RESULTS: The serum telomerase enzyme concentration was lower in ACS (36.61 ± 1.54) and SCAD (36.79 ± 1.57) when compared to the control group (37.03 ± 2.25). However, this difference did not reach statistical significance (p = 0.890). The hTERT gene expression acting in telomerase enzyme synthesis was 2.7-fold lower in ACS group (p = 0.070) and 2.2-fold lower in the SCAD group (p = 0.101) compared to the control group. Patients were followed for a median of 32 months (minimum: 0.1, maximum: 46.8). The serum telomerase concentrations in patients who died and those survived in the SCAD group (35.98 ± 2.02 vs 36.86 ± 1.52 ng/ml, respectively; p = 0.529) were similar to those in the ACS group (36.39 ± 1.08 vs 36.63 ± 1.60 ng/ml, respectively p = 0.993). CONCLUSIONS: In the current study, telomerase activity or hTERT expression was similar in patients with ACS, SCAD, and controls. Moreover, telomerase activity was not associated with all- cause mortality during the 32-month follow-up (Tab. 3, Fig. 1, Ref. 29).

The application of quantitative telomerase activity measurement as an important indicator to monitor the cardiomyocyte differentiation process of human induced pluripotent stem cells under defined conditions.

The construction of an in vitro differentiation system for human induced pluripotent stem cells (hiPSCs) has made exciting progress, but it is still of great significance to clarify the differentiation process. The use of conventional genetic and protein-labeled microscopes to observe or detect different stages of hiPSC differentiation is not specific enough and is cumbersome and time-consuming. In this study, in addition to analyzing the expression of gene/protein-related markers, we used a previously reported simple and excellent quantitative method of cellular telomerase activity based on a quartz crystal microbalance (TREAQ) device to monitor the dynamic changes in cellular telomerase activity in hiPSCs during myocardial differentiation under chemically defined conditions. Finally, by integrating these results, we analyzed the relationship between telomerase activity and the expression of marker genes/proteins as well as the cell type at each study time point. This dynamic quantitative measurement of cellular telomerase activity should be a promising indicator for monitoring dynamic changes in a stage of hiPSC differentiation and inducing cell types. This study provided a quantitative, dynamic and simple monitoring index for the in vitro differentiation process of hiPSC-CMs, which was a certain reference value for the optimization and improvement of the induction system.

The neuro-protective role of telomerase via TERT/TERF-2 in the acute phase of spinal cord injury.

PURPOSE: To investigate the interaction of telomerase activity and telomere length on neuro-protection or neuro-degeneration effects after spinal cord injury (SCI). METHODS: A contusive SCI model was developed using 56 Sprague-Dawley rats. Seven rats were allocated into acute injury phase groups (1, 3, 8, 24, and 48 h), and sub-acute and chronic injury phase groups (1, 2, and 4 weeks). Telomerase activity was assessed by telomerase reverse transcriptase (TERT) and telomeric repeat binding factor-2 (TERF-2). Differentiation of activated neural stem cells was investigated by co-expression of neuronal/glial cell markers. Apoptosis expression was also investigated by caspase-3, 8, and 9 using terminal deoxynucleotidyl transferase dUTP nick end labelling staining. Immunofluorescence staining and western blotting were performed for quantitative analyses. RESULTS: Expression of TERT increased gradually until 24 h post-injury, and was decreased following SCI (P < 0.05). TERF-2 also was increased following SCI until 24 h post-injury and then decreased with time (P < 0.05). Co-localization of TERT and TERF-2 was higher at 24 h post-injury. High expression of TERT was seen in neurons (Neu N Ab), however, expression of TERT was relatively lower in astrocytes and oligodendrocytes. Apoptosis analysis showed persistent high expression of caspases-3, -9, and -8 during the observation period. CONCLUSIONS: Increased TERT and TERF-2 activity were noted 24 h post-injury in the acute phase of SCI with TERF-2 maintaining telomeric-repeat length. Our results suggest that increased activity of telomere maintenance may be related to neuro-protective mechanisms against subsequent apoptosis resulting from DNA damage after acute SCI.

Angelica sinensis extract induces telomere dysfunction, cell cycle arrest, and mitochondria-mediated apoptosis in human glioblastoma cells.

Glioblastoma (GB) is one of the most aggressive and malignant tumors of the central nervous system. Conventional treatment for GB requires surgical resection followed by radiotherapy combined with temozolomide chemotherapy; however, the median survival time is only 12-15 months. Angelica sinensis Radix (AS) is commonly used as a traditional medicinal herb or a food/dietary supplement in Asia, Europe, and North America. This study aimed to investigate the effect of AS-acetone extract (AS-A) on the progression of GB and the potential mechanisms underlying its effects. The results indicated that AS-A used in this study showed potency in growth inhibition of GB cells and reduction of telomerase activity. In addition, AS-A blocked the cell cycle at the G0/G1 phase by regulating the expression of p53 and p16. Furthermore, apoptotic morphology, such as chromatin condensation, DNA fragmentation, and apoptotic bodies, was observed in AS-A-treated cells, induced by the activation of the mitochondria-mediated pathway. In an animal study, AS-A reduced tumor volume and prolonged lifespans of mice, with no significant changes in body weight or obvious organ toxicity. This study confirmed the anticancer effects of AS-A by inhibiting cell proliferation, reducing telomerase activity, altering cell cycle progression, and inducing apoptosis. These findings suggest that AS-A has great potential for development as a novel agent or dietary supplement against GB.

In Vitro Assessment of Gold Nanoparticles on Telomerase Activity and Telomere Length in Human Fibroblasts.

Telomerase activity coincides with lengthening of the ends of chromosomes known as telomeres. Telomere length is used as a marker for cellular aging. Telomeres shorten over time as cells divide, and certain bioactive compounds such as gold nanoparticles (AuNPs) may slow the shortening of telomeres by increasing telomerase activity. The objective of the present study is to assess the effect of AuNPs on telomerase activity and telomere length in human fibroblasts. Telomerase activity was measured using enzyme-linked immunosorbent assay (ELISA) in primary human lung fibroblasts (IMR90) and using quantitative PCR-based telomeric repeat amplification protocol (Q-TRAP) in primary human dermal fibroblasts, neonatal (HDFn). Telomere length was determined by Telomere Analysis Technology (TAT®)assay in HDFn. In IMR90, all AuNP treatments showed significant increases in telomerase activity when compared to earlier passages. HDFn treated with AuNPs at 0 ppm, 0.05 ppm, 0.5 ppm, or 5 ppm did not show significant differences in telomerase activity compared to the control group. Significant differences in telomere length in HDFn were observed at 2 weeks of 0.05 and 0.5 ppm AuNPs under oxidative culture conditions as compared to the control group. The study showed preliminary evidence that AuNPs may increase telomerase activity and decelerate the shortening of telomeres in human fibroblasts, suggesting its potential anti-aging effects, which warrants further investigation.

Influence of Moxonidine and Bisoprolol on Morphofunctional Condition of Arterial Wall and Telomerase Activity in Postmenopausal Women with Arterial Hypertension and Osteopenia. The Results from a Moscow Randomized Study.

PURPOSE: To compare the effect of 12 months of treatment with moxonidine or bisoprolol on telomerase activity (TA) and parameters characterizing the arterial wall state in postmenopausal women with arterial hypertension (AH) and osteopenia. METHODS: An open-label randomized study with 114 postmenopausal women with hypertension and osteopenia; pulse wave velocity (PWV), intima-media thickness (IMT), and TA were analyzed initially and after 12 months of therapy with moxonidine (n = 57) or bisoprolol (n = 57). RESULTS: Both medications effectively lowered blood pressure (BP) in both groups. After 12 months, the moxonidine group showed a significant increase in TA by 45.5% (from 0.87 to 1.15; p < 0.001), in contrast to the bisoprolol group, where TA decreased by 14.1% (from 0.89 to 0.74; p = 0.001). Within 12 months, in the moxonidine group, PWV decreased by 1.9% (from 10.35 ± 2.56 to 10.05 ± 2.29 m/s; p = 0.039), and in the bisoprolol group it increased by 5.8% (from 10.36 ± 2.47 to 11.26 ± 2.60 m/s; p < 0.001). In the moxonidine group, IMT increased by 3.5% on the right and 1.4% on the left, in the bisoprolol group - by 5.7% on the right and 4.2% on the left. CONCLUSION: A 12-month treatment with moxonidine but not with bisoprolol in postmenopausal women with AH and osteoporosis was associated with a decrease of arterial stiffness seen as statistically significantly reduced PVW and with increased TA.

Leukocyte telomere length in women with and without polycystic ovary syndrome: a systematic review and meta-analysis.

AIM: To study the telomere length and the telomerase activity in women with and without polycystic ovary syndrome (PCOS). METHODS: Relevant studies were searched from PubMed, Embase, and LILACS online databases and manual screening. The mean differences (MDs) or standardized MDs (SMDs) with their 95% confidence intervals (CIs) were calculated. The methodological quality of included studies was evaluated with the Newcastle-Ottawa Scale (NOS), and heterogeneity with the I2 and Tau2 statistics. RESULTS: Six studies including 2109 non-pregnant women with (n = 1155) or without (n = 954) PCOS assessed leukocyte telomere length. There was a non-significant leukocyte telomere length difference (SMD = 0.25, 95% CI: -0.01, 0.51, p = .06, I2 = 81%, Tau2 = 0.08) comparing PCOS patients with the control group. Studied PCOS women were younger (MD = -1.39, 95% CI: -2.47, -0.31 years, I2 = 83%), and had higher body mass index (BMI; MD = 3.66, 95% CI: 2.11, 5.20 kg/m2, I2 = 94%). There were significantly higher testosterone (SMD = 0.88, 95% CI: 0.65, 1.10) and luteinizing hormone levels (SMD = 0.60, 95% CI: 0.12, 1.08) in women with PCOS as compared to controls. There was a low risk of bias and there were not sufficient studies to meta-analyze other cell types. CONCLUSIONS: Leukocyte telomere length did not differ between women with and without PCOS. Further studies with large sample sizes and including other outcomes are warranted to further substantiate the reported evidence.

PinX1 Depletion Improves Liver Injury in a Mouse Model of Nonalcoholic Fatty Liver Disease via Increasing Telomerase Activity and Inhibiting Apoptosis.

PIN2/TRF1-interacting telomerase inhibitor 1 (PinX1) can inhibit tumor growth by inhibiting telomerase activity. However, only few studies investigated the expression and function of PinX1 in nonalcoholic fatty liver disease (NAFLD). Thus, here we aimed to explore the roles of PinX1 in high-fat diet (HFD)-induced NAFLD in mice and in isolated hepatocytes. The mRNA expression of PinX1 and mTERT as well as telomere length were analyzed by RT-PCR. Pathological changes were detected by HE staining and oil red O staining. Triglyceride, cholesterol, alanine aminotransferase, aspartic aminotransferase, and telomerase activity were detected by ELISA. Hepatocyte apoptosis was determined by TUNEL and flow cytometry, and protein expression was analyzed by western blotting. We found that the expression of PinX1 was upregulated in the HFD group compared with the WT group. PinX1 knockout improved HFD-induced liver injury in mice and exhibited less lipid accumulation in hepatocytes. Moreover, telomere length, telomerase activity, and mTERT expression were significantly reduced in liver tissues of HFD-induced mice and palmitic acid-induced hepatocytes, while PinX1 knockout attenuated the effect. Furthermore, HFD-induced PinX1-/- mice exhibited less hepatocyte apoptosis than HFD-induced WT mice. Besides, PinX1 knockout inhibited the increase of cleaved caspase-3 and cleaved PARP expression in vivo and in vitro. Moreover, inhibition of mTERT reversed the effect of PinX1 knockout in hepatocytes. Taken together, our findings indicate that PinX1 promotes hepatocyte apoptosis and lipid accumulation by decreasing telomere length and telomerase activity in the development of NAFLD. PinX1 might be a target for the treatment of NAFLD.

Role of DNA Methylation and CpG Sites in the Viral Telomerase RNA Promoter during Gallid Herpesvirus 2 Pathogenesis.

Gallid herpesvirus type 2 (GaHV-2) is an oncogenic alphaherpesvirus that induces malignant T-cell lymphoma in chicken. GaHV-2 encodes a viral telomerase RNA subunit (vTR) that plays a crucial role in virus-induced tumorigenesis, enhances telomerase activity, and possesses functions independent of the telomerase complex. vTR is driven by a robust viral promoter, highly expressed in virus-infected cells, and regulated by two c-Myc response elements (c-Myc REs). The regulatory mechanisms involved in controlling vTR and other genes during viral replication and latency remain poorly understood but are crucial to understanding this oncogenic herpesvirus. Therefore, we investigated DNA methylation patterns of CpG dinucleotides found in the vTR promoter and measured the impact of methylation on telomerase activity. We demonstrated that telomerase activity was considerably increased following viral reactivation. Furthermore, CpG sites within c-Myc REs showed specific changes in methylation after in vitro reactivation and in infected animals over time. Promoter reporter assays indicated that one of the c-Myc REs is involved in regulating vTR transcription, and that methylation strongly influenced vTR promoter activity. To study the importance of the CpG sites found in c-Myc REs in virus-induced tumorigenesis, we generated recombinant virus containing mutations in CpG sites of c-Myc REs together with the revertant virus by two-step Red-mediated mutagenesis. Introduced mutations in the vTR promoter did not affect the replication properties of the recombinant viruses in vitro In contrast, replication of the mutant virus in infected chickens was severely impaired, and tumor formation completely abrogated. Our data provides an in-depth characterization of c-Myc oncoprotein REs and the involvement of DNA methylation in transcriptional regulation of vTR.IMPORTANCE Previous studies demonstrated that telomerase RNAs possess functions that promote tumor development independent of the telomerase complex. vTR is a herpesvirus-encoded telomerase RNA subunit that plays a crucial role in virus-induced tumorigenesis and is expressed by a robust viral promoter that is highly regulated by the c-Myc oncoprotein binding to the E-boxes. Here, we demonstrated that the DNA methylation patterns in the functional c-Myc response elements of the vTR promoter change upon reactivation from latency, and that demethylation strongly increases telomerase activity in virus-infected cells. Moreover, the introduction of mutation in the CpG dinucleotides of the c-Myc binding sites resulted in decreased vTR expression and complete abrogation of tumor formation. Our study provides further confirmation of the involvement of specific DNA methylation patterns in the regulation of vTR expression and vTR importance for virus-induced tumorigenesis.

PAX5 activates telomerase activity and proliferation in keloid fibroblasts by transcriptional regulation of SND1, thus promoting keloid growth in burn-injured skin.

OBJECTIVE: Staphylococcal nuclease domain-containing 1 (SND1) that functioned as an oncogene in a variety of tumors was upregulated in burn-injured skin tissues, and this study aims to investigate the effect of SND1 on keloid and elucidate the underlying mechanism. METHODS: Keloid fibroblasts (KFs) and normal skin fibroblasts (NFs) were isolated from the keloid tissues and adjacent normal skin tissues of keloid patients. The SND1 expression was assessed in keloid tissues and KFs with Western blot assay. Gain- and loss-of-function experiments were performed to investigate the role of SND1 in proliferation, colony formation, telomerase activity, expression of fibrogenic genes and production of pro-inflammatory factors in KFs. Chromatin immunoprecipitation (CHIP) and Dual-luciferase reporter gene assays were used to verify the interaction of Paired-box gene 5 (PAX5) on SND1 promoter. Then, a series of rescue experiments were performed to verify the effects of SND1 overexpression on PAX5 knockdown-mediated KF functions. Finally, the role of SND1 in keloid formation in vivo was validated in mice with keloid implantation. RESULTS: SND1 was upregulated in keloid tissues and KFs. SND1 positively regulated proliferation, colony formation, telomerase activity, production of pro-inflammatory factors and expression of fibrogenic genes. PAX5 directly bound to the SND1 promoter to transcriptionally regulate SND1 expression and positively regulated SND1-mediated KF functions via the ERK/JNK pathway. In vivo assay further demonstrated that SND1 displayed a positive effect on keloid formation. CONCLUSION: SND1 transcriptionally regulated by PAX5 promotes keloid formation through activating telomerase activity via the ERK/JNK signaling pathways, which provides a promising therapeutic target for clinical treatment of burned skin keloid.

Heterogeneity of telomerase reverse transcriptase mutation and expression, telomerase activity and telomere length across human cancer cell lines cultured in vitro.

Promoter region of the telomerase reverse transcriptase gene (TERTp) constitutes a regulatory element capable to affect TERT expression (TE), telomerase activity (TA) and telomere length (TL). TERTp mutation status, TL, TA and TE were assessed in 27 in vitro cultured human cell lines, including 11 solid tumour, 13 haematological and 3 normal cell lines. C228T and C250T TERTp mutations were detected in 5 solid tumour and none of haematological cell lines (p = 0.0100). As compared to other solid tumour cell lines, those with the presence of somatic mutations were characterized by: shorter TL, lower TA and TE. Furthermore, cell lines carrying TERTp mutations showed a linear correlation between TE and TA (R = 0.9708, p = 0.0021). Moreover, haematological cell lines exhibited higher TE compared to solid tumour cell lines (p = 0.0007). TL and TA were correlated in both solid tumour (R = 0.4875, p = 0.0169) and haematological (R = 0.4719, p = 0.0095) cell lines. Our results based on the in vitro model suggest that oncogenic processes may differ between solid tumours and haematological malignancies with regard to their TERT gene regulation mechanisms.

Nonradioactive direct telomerase activity detection using biotin-labeled primers.

BACKGROUND: Telomerase is a ribonucleoprotein enzyme responsible for maintenance of telomere length which expressed in more than 85% of cancer cells but undetectable in most normal tissue cells. Therefore, telomerase serves as a diagnostic marker of cancers. Two commonly used telomerase activity detection methods, the telomerase repeated amplification protocol (TRAP) and the direct telomerase assay (DTA), have disadvantages that mainly arise from reliance on PCR amplification or the use of an isotope. A safe, low-cost and reliable telomerase activity detection method is still lacking. METHOD: We modified DTA method using biotin-labeled primers (Biotin-DTA) and optimized the method by adjusting cell culture temperature and KCl concentration. The sensitivity of the method was confirmed to detect endogenous telomerase activity. The reliability was verified by detection of telomerase activity of published telomerase regulators. The stability was confirmed by comparing the method with TRAP method. RESULTS: Cells cultured in 32°C and KCl concentration at 200 mM or 250 mM resulted in robust Biotin-DTA signal. Endogenous telomerase activity can be detected, which suggested an similar sensitivity as DTA using radioactive isotope markers. Knockdown of telomerase assembly regulator PES1 and DKC1 efficiently reduced telomerase activity. Compared with TRAP method, Biotin-DTA assay offers greater signal stability over a range of analyte protein amounts. CONCLUSION: Biotin-labeled, PCR-free, and nonradioactive direct telomerase assay is a promising new method for the easy, low-cost, and quantitative detection of telomerase activity.

Targeting Telomere Biology in Acute Lymphoblastic Leukemia.

Increased cell proliferation is a hallmark of acute lymphoblastic leukemia (ALL), and genetic alterations driving clonal proliferation have been identified as prognostic factors. To evaluate replicative history and its potential prognostic value, we determined telomere length (TL) in lymphoblasts, B-, and T-lymphocytes, and measured telomerase activity (TA) in leukocytes of patients with ALL. In addition, we evaluated the potential to suppress the in vitro growth of B-ALL cells by the telomerase inhibitor imetelstat. We found a significantly lower TL in lymphoblasts (4.3 kb in pediatric and 2.3 kb in adult patients with ALL) compared to B- and T-lymphocytes (8.0 kb and 8.2 kb in pediatric, and 6.4 kb and 5.5 kb in adult patients with ALL). TA in leukocytes was 3.2 TA/C for pediatric and 0.7 TA/C for adult patients. Notably, patients with high-risk pediatric ALL had a significantly higher TA of 6.6 TA/C compared to non-high-risk patients with 2.2 TA/C. The inhibition of telomerase with imetelstat ex vivo led to significant dose-dependent apoptosis of B-ALL cells. These results suggest that TL reflects clonal expansion and indicate that elevated TA correlates with high-risk pediatric ALL. In addition, telomerase inhibition induces apoptosis of B-ALL cells cultured in vitro. TL and TA might complement established markers for the identification of patients with high-risk ALL. Moreover, TA seems to be an effective therapeutic target; hence, telomerase inhibitors, such as imetelstat, may augment standard ALL treatment.

Noncoding telomeric repeat-containing RNA inhibits the progression of hepatocellular carcinoma by regulating telomerase-mediated telomere length.

Telomeric repeat-containing RNA (TERRA) is closely involved in the regulation of telomere length, which plays critical roles in tumorigenesis. However, the biological significance of TERRA in hepatocellular carcinoma (HCC) remains largely unknown. In this study, we found that HCC cells show a frequent downregulation of TERRA and its positive regulator TTAGGG repeat binding factor-1 (TRF1), whereas the negative regulator TTAGGG repeat binding factor-1 (TRF2) was upregulated. We found that TERRA, TRF1, and TRF2 contributed to poor prognosis of HCC patients. Importantly, we found that the downregulation of TERRA significantly promoted HCC cell growth and metastasis in vitro and in vivo, whereas the upregulation of TERRA showed an opposite effect. Mechanistically, downregulation of TERRA significantly increased telomerase activity and promoted telomere elongation. Moreover, the inhibitory effects of TERRA overexpression on the growth and metastasis of HCC cells were reversed by treatment with TA-65 that activates telomerase activity. In contrast, the protumor effect of TERRA downregulation was reversed by treatment with TMPyP4 that inhibits telomerase activity. Our findings reveal that TERRA plays a critical role in HCC cell growth and metastasis, indicating that TERRA is a potential therapeutic target for HCC.

Pathobiological Mechanisms of Endothelial Dysfunction Induced by tert-Butyl Hydroperoxide via Apoptosis, Necrosis and Senescence in a Rat Model.

Background: Endothelial dysfunction is one of the underlying causes for vascular diseases. tert-Butyl hydroperoxide (t-BHP), a short-chain lipid hydroperoxide analog, has been reported to cause adverse effects in different systems. However, the adverse actions of t-BHP on inducing endothelial dysfunction are unclear and remain under investigation. Aim of the present study was to identify the pathobiological mechanisms of t-BHP in rat aortic endothelial cells and thoracic aorta. Methods: Primary cultured cells were treated with vehicle or t-BHP (50, 100, 250, 500, and 1,000 µM). Cells were harvested and specific analyses regarding cellular apoptosis, necrosis, and senescence were conducted. Additionally, t-BHP (0.1, 0.2, and 0.4 mmol/kg body weight) or vehicle were administered to male rats (the young group at 6 weeks of age and the mature adult group at 24 weeks of age) daily through intraperitoneal injections. At 10 days after the first drug treatment apoptotic endothelial toxicity was evaluated by biochemical, histological, and immunofluorescent staining analyses. Results: Dose-dependent effects of t-BHP were observed for the reduction of cell viability, deterioration of cell toxicity, initiation of cell cycle arrest, and triggering of apoptosis and necrosis. Moreover, increase of cells stained positive for senescence-associated beta-galactosidase (SA-ß-Gal), amelioration of telomerase activity, and precipitations of necrotic, cell cycle, and apoptotic signaling regulatory proteins were also found in the in vitro model. In the in vivo study, results indicated that t-BHP at higher doses enlarged the intima-medial thickness of descending aorta in the mature adult group, but led to aortic narrowing in the young group. Increased injuries were observed by upregulating endothelial apoptosis- and senescence-positive staining, along with caspase-3 activity and down-regulating telomerase activity. Conclusion: These results confirmed that t-BHP impaired aortic endothelial cell survival at least partially by the activation of p53-mediated signaling pathways, inhibition of cell cycle regulatory proteins, and initiation of cellular senescence-related signaling pathways. In conclusion, t-BHP was found to be a major trigger for impairing aortic endothelial cell survival and deteriorating vascular dysfunction in experimental practice.

The association between dietary quality indices and serum telomerase activity in patient candidates for CABG.

BACKGROUND: Diet and dietary habits are major determinants of human telomere length. Telomerase activity is affected mostly by oxidative stress and inflammation. However, the association of telomerase activity with dietary quality indices has not been evaluated before. In the current work, we aimed to test the association of telomerase activity with dietary antioxidant quality score (DAQ), dietary inflammatory index and dietary patterns in patients who were candidate for coronary artery bypass grafting surgery (CABG). METHODS AND MATERIALS: In the current cross-sectional study, 454 candidates for the CABG were enrolled from Tehran Heart Center-Coronary Outcome Measurement (THC-COM) cohort. Laboratory measurements included Hb-A1C, serum lipid profile, creatinine, blood urea nitrogen, hematocrit, lipoprotein (LP)-a, telomerase activity, serum vitamin D and C-reactive protein. Dietary status was measured by semiquantitative food frequency questionnaire, and dietary indices were calculated. Dietary patterns were extracted by factor analysis method. RESULTS: High telomerase activity was associated with lower prevalence of myocardial infarction (MI) (P = 0.04), high dietary vitamin E and high total dietary antioxidant quality scores. Telomerase activity in top quartile of neo-traditional dietary pattern was higher than other quartiles (P = 0.021). No significant association between telomerase activity and other dietary patterns was obtained. Higher telomerase activity was also associated with higher serum creatinine and lower LP-(a) concentrations (P < 0.05). CONCLUSION: To our findings, higher telomerase activity was associated with higher DAQ and lower MI prevalence. It seems that adherence to healthy diet increases serum telomerase activity and reduced telomerase concentration is associated with increased cardio-metabolic risk factors. Moreover, adherence to neo-traditional pattern with higher intake of low-fat dairy products was associated with higher telomerase activity. LEVEL OF EVIDENCE: Level V: A well-designed observational cross-sectional study.

Active telomerase during leaf growth and increase of age in plants from Agave tequilana var. Azul.

In plants, previous studies show that telomerase activity contributes to the maintenance of telomeric length for the proper development of organs and tissues. In this work, we investigated telomerase activity in A. tequilana during several years of cultivation. We found that during growth of the leaf there are two crucial phases: (1) the onset of cell elongation in 3 years and (2) differentiation of vascular bundles in 6 years. This coincides with the ages where the highest telomerase activity is seen. Therefore indicates that telomerase is associated with cellular activities such as; elongation, division, and cell differentiation. Likewise, we detected high activity during the period of vegetative growth, indicating that telomerase also contributes to telomeric maintenance on the leaf in A. tequilana.

Lifetime extension of humpback whale skin fibroblasts and their response to lipopolysaccharide (LPS) and a mixture of polychlorinated biphenyls (Aroclor).

Marine mammals, such as whales, have a high proportion of body fat and so are susceptible to the accumulation, and associated detrimental health effects, of lipophilic environmental contaminants. Recently, we developed a wild-type cell line from humpback whale fibroblasts (HuWa). Extensive molecular assessments with mammalian wild-type cells are typically constrained by a finite life span, with cells eventually becoming senescent. Thus, the present work explored the possibility of preventing senescence in the HuWa cell line by transfection with plasmids encoding the simian virus large T antigen (SV40T) or telomerase reverse transcriptase (TERT). No stable expression was achieved upon SV40 transfection. Transfection with TERT, on the other hand, activated the expression of telomerase in HuWa cells. At the time of manuscript preparation, the transfected HuWa cells (HuWaTERT) have been stable for at least 59 passages post-transfection. HuWaTERT proliferate rapidly and maintain initial cell characteristics, such as morphology and chromosomal stability. The response of HuWaTERT cells to an immune stimulant (lipopolysaccharide (LPS)) and an immunotoxicant (Aroclor1254) was assessed by measurement of intracellular levels of the pro-inflammatory cytokines interleukin (IL)-6, IL-1ß and tumour necrosis factor (TNF)-α. HuWaTERT cells constitutively express IL-6, IL-1ß and TNFα. Exposure to neither LPS nor Aroclor1254 had an effect on the levels of these cytokines. Overall, this work supports the diverse applicability of HuWa cell lines in that they display reliable long-term preservation, susceptibility to exogenous gene transfer and enable the study of humpback whale-specific cellular response mechanisms.