The role of erythrocytes and erythroid progenitor cells in tumors.

In the current research context of precision treatment of malignant tumors, the advantages of immunotherapy are unmatched by conventional antitumor therapy, which can prolong progression-free survival and overall survival. The search for new targets and novel combination therapies can improve the efficacy of immunotherapy and reduce adverse effects. Since current research targets for immunotherapy mainly focus on lymphocytes, little research has been done on erythrocytes. Nucleated erythroid precursor stem cells have been discovered to play an essential role in tumor progression. Researchers are exploring new targets and therapeutic approaches for immunotherapy from the perspective of erythroid progenitor cells (EPCs). Recent studies have shown that different subtypes of EPCs have specific surface markers and distinct biological roles in tumor immunity. CD45+ EPCs are potent myeloid-derived suppressor cell-like immunosuppressants that reduce the patient's antitumor immune response. CD45- EPCs promote tumor invasion and metastasis by secreting artemin. A specific type of EPC also promotes angiogenesis and provides radiation protection. Therefore, EPCs may be involved in tumor growth, infiltration, and metastasis. It may also be an important cause of anti-angiogenesis and immunotherapy resistance. This review summarizes recent research advances in erythropoiesis, EPC features, and their impacts and processes on tumors.

Integrative transcriptional characterization of cell cycle checkpoint genes promotes clinical management and precision medicine in bladder carcinoma.

Background: The aberrant regulation of cell cycle is significantly correlated with cancer carcinogenesis and progression, in which cell cycle checkpoints control phase transitions, cell cycle entry, progression, and exit. However, the integrative role of cell cycle checkpoint-related genes (CRGs) in bladder carcinoma (BC) remains unknown. Methods: The transcriptomic data and clinical features of BC patients were downloaded from The Cancer Genome Atlas (TCGA), used to identify CRGs correlated with overall survival (OS) by univariate Cox regression analysis. Then, the multivariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses further developed a prognostic CRG signature, which was validated in three external datasets retrieved from Gene Expression Omnibus (GEO). The receiver operating characteristic curve (ROC) analysis was conducted for evaluating the performance of the CRG signature in prognosis prediction. RNA sequencing (RNA-Seq) was performed to explore the expression difference in the identified CRGs between tumor and normal tissue samples from 11 BC patients in the local cohort. Ultimately, genomic profiles and tumor microenvironment (TME), and the Genomics of Drug Sensitivity in Cancer (GDSC) were investigated to guide precision treatment for BC patients with different CRG features. Results: The novel constructed 23-CRG prognostic signature could stratify BC patients into high-risk and low-risk groups with significantly different outcomes (median OS: 13.64 vs. 104.65 months). Notably, 19 CRGs were the first to be identified as being associated with BC progression. In three additional validation datasets (GSE13507, GSE31684, and GSE32548), higher CRG scores all indicated inferior survival, demonstrating the robust ability of the CRG signature in prognosis prediction. Moreover, the CRG signature as an independent prognostic factor had a robust and stable risk stratification for BC patients with different histological or clinical features. Then, a CRG signature-based nomogram with a better performance in prognostic prediction [concordance index (C-index): 0.76] was established. Functional enrichment analysis revealed that collagen-containing extracellular matrix (ECM), and ECM-related and MAPK signaling pathways were significantly associated with the signature. Further analysis showed that low-risk patients were characterized by particularly distinctive prevalence of FGFR3 (17.03% vs. 6.67%, p < 0.01) and POLE alterations (7.97% vs. 2.50%, p < 0.05), and enrichment of immune infiltrated cells (including CD8+ T cells, CD4+ naïve T cells, follicular helper T cells, Tregs, and myeloid dendritic cells). RNA-seq data in our local cohort supported the findings in the differentially expressed genes (DEGs) between tumor and normal tissue samples, and the difference in TME between high-risk and low-risk groups. Additionally, CRG signature score plus FGFR3 status divided BC patients into four molecular subtypes, with distinct prognosis, TME, and transcriptomic profiling of immune checkpoint genes. Of note, CRG signature score plus FGFR3 status could successfully distinguish BC patients who have a higher possibility of response to immunotherapy or chemotherapy drugs. Conclusions: The CRG signature is a potent prognostic model for BC patients, and in combination with FGFR3 alterations, it had more practical capacity in the prediction of chemotherapy and immunotherapy response, helping guide clinical decision-making.

The clinical effectiveness and safety of traditional Chinese medicine Jinfeng pill in adjuvant treatment of infertility with polycystic ovary syndrome: A protocol for systematic review and meta-analysis.

BACKGROUND: Polycystic ovary syndrome (PCOS) is the main cause of infertility in women, the essence of which is an endocrine disorder syndrome with abnormal sugar metabolism and reproductive dysfunction, and the incidence rate of about 6% of women. Traditional Chinese medicine (TCM) Jinfeng pill has achieved very good clinical results in the treatment of infertility with PCOS, but there is currently a lack of strong evidence-based medical evidence. This study uses meta-analysis method to analyze the clinical effectiveness and safety of TCM Jinfeng pill in the treatment of infertility with PCOS, hoping to provide help for the clinical treatment of infertility with PCOS. METHODS: Using the computer to retrieve SinoMed, CNKI, VIP, WANFANG Database, as well as Public, The Cochrane library, Medline (Ovid SP), Embase and other foreign language databases, while manually retrieving the relevant magazine supplements, special issues, professional materials, network information, and so on. The retrieval time is from the beginning of each database to June 2021. The selected literature is evaluated using the Cochrane System Rating Manual Bias Risk Tool. Statistical analysis and graphics of the inclusion literature are performed using Review Manager 5.3 statistical software. RESULTS: All the results of this study on the clinical effectiveness and safety of TCM Jinfeng pill in adjuvant treatment of infertility with PCOS will be published in a peer-reviewed academic journal of medicine. ETHICS AND DISSEMINATION: The type of study is systematic evaluation, the whole process of research does not involve human trials, the data used in the institute are obtained through published literature, so ethical review is not suitable for this study. OSF REGISTRATION NUMBER: 10.17605/OSF.IO/JEP2D. (https://osf.io/jep2d). CONCLUSION: Our research will provide evidence-based medical evidence on whether the TCM Jinfeng pill is effective and safe in the treatment of infertility with PCOS.

Downregulation of miR-218 by nicotine promotes cell proliferation through targeting CDK6 in non-small cell lung cancer.

BACKGROUND: Nicotine, an important component of tobacco, is a major risk factor of lung cancer, but the mechanism through which nicotine promotes lung cancer development remains unclear. METHODS: Eighty patients with lung cancer were enrolled in this study, 34 of whom did not smoke and the others did. The expression of miR-218 and CDK6 messenger RNA (mRNA) was measured using quantitative reverse transcription polymerase chain reaction (qRT-PCR). A luciferase reporter system was used to identify the direct target of miR-218. The protein expression of CDK6 was analyzed by using Western blotting. Cell proliferation was analyzed using an approach of calculation of cell number under a microscope. RESULTS: Nicotine decreased miR-218 expression in non-small cell lung cancer (NSCLC) cells and promoted proliferation of NSCLC cells. Smoking patients with NSCLC had lower expression of miR-218 in tumor compared with NSCLC patients who did not smoke. We found that miR-218 directly targeted the CDK6 mRNA 3'untranslated region and inhibited its expression in NSCLC cells and also observed a negative correlation between the expression of miR-218 and CDK6 mRNA in lung cancer tissues. Furthermore, miR-218- or nicotine-induced proliferative effects of NSCLC cells were rescued by the recovery of the expression level of CDK6. CONCLUSION: Nicotine promotes proliferation of NSCLC cells through regulating the miR-218/CDK6 axis, which may be a potential therapeutic target for lung cancer.

Vitamin E administration erases an enhanced oxidation in multiple sclerosis.

Systemic peroxidation status has been reported as a pathogenic factor for multiple sclerosis (MS). Systemically elevated oxidation levels are associated with serum lipid peroxidation and somatic telomere length (TL) shortening. We investigated whether vitamin E (VE) administration suppresses peroxidation and improves clinical symptoms in 34 MS patients. We analyzed serum lipid peroxidation and degree of TL in circulating leukocytes of MS patients before and after VE treatment. The oxidation level was enhanced and TL was shortened in MS. The MS population treated with VE 400 mg/day for 3 months showed significantly reduced serum lipid oxidation level with maintenance of TL. These findings showed that systemic peroxidation is associated with the development of MS. Antioxidants such as vitamin E can be candidates for supplementary therapeutic agents for MS.

Effectiveness and Safety of the Combination of the Traditional Chinese Medicine Prescription Jade Screen and Desloratadine in the Treatment of Chronic Urticaria: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: The aim of this study is to systematically evaluate the clinical efficacy and safety of the traditional Chinese medicine prescription Jade Screen combined with desloratadine in the treatment of chronic urticaria. METHODS: Two researchers independently conducted literature searches. The extracted data were analyzed using Rev Man 5.2.3 software. The established retrieval time range of the various databases was up to 15 March, 2017. RESULTS: Sixteen randomized controlled trials were included in this study. The results of the meta-analysis showed that the total effective rate of using Jade Screen and desloratadine in combination to treat chronic urticaria was higher than that with desloratadine alone (P < 0.00001), while its recurrence rate (P < 0.00001) and symptom score (P = 0.006) were both significantly lower than the latter. The rate of adverse reaction in the combination group was lower than that when orally taking desloratadine alone (P = 0.74), and the serum level of total IgE in the combination group was lower than that when orally taking desloratadine alone (P = 0.82); however, the results of the rate of adverse reaction and the serum level of total IgE were insignificant. CONCLUSION: Using Jade Screen and desloratadine together to treat chronic urticaria gains a better clinical effect than using desloratadine alone.

Potential of bone marrow mesenchymal stem cells in rejuvenation of the aged skin of rats.

The aim of the present study was to evaluate the anti-aging effects of bone marrow-mesenchymal stem cells (BM-MSCs) in a D-galactose-induced skin aging rat model. Male Sprague Dawley rats were randomly divided into four groups (n=10/group) as follows: Normal control group; skin aging model group; MSC-treated group by subcutaneous multi-point injection. The skin aging model was established by a daily subcutaneous injection of 15% D-galactose (1,000 mg/kg) for 8 weeks. Rats in the MSC-treated groups were administered 3×106/ml BM-MSCs/green fluorescent protein (GFP) for 4 weeks, administered once per week. Oxidative/antioxidative parameters were evaluated, and morphological and ultrastructure analyses were performed. Rats in the model group exhibited the typical changes of aging skin. Compared with the control group, rats in the model group had significantly increased malondialdehyde (MDA) content (P<0.01), and decreased serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities (P<0.05). MSC treatment markedly ameliorated aging-induced oxidative stress in the skin. Histologically, rats in the model group exhibited loosely arranged epidermal cell layers and disorganized collagen fibers. BM-MSC treatment significantly improved the histological abnormalities, which was similar to those in the control group. In addition, 7 days after the final cell transplantation, GFP-positive cells were observed by fluorescence microscopy to be distributed in the dermis. Injection of BM-MSCs significantly improved the D-galactose-induced histological abnormalities of the skin, by promoting an antioxidant response and ameliorating oxidative stress in aged skin. Thus, BM-MSCs may be beneficial in the rejuvenation of aged skin.

Insulin-like growth factor 1 receptor-mediated cell survival in hypoxia depends on the promotion of autophagy via suppression of the PI3K/Akt/mTOR signaling pathway.

Hypoxia is widely accepted as a fundamental biological phenomenon, which is strongly associated with tissue damage and cell viability under stress conditions. Insulin-like growth factor­1 (IGF­1) is known to protect tissues from multiple types of damage, and protect cells from apoptosis. Hypoxia is a regulatory factor of the IGF system, however the role of the IGF-1 receptor (IGF­1R) in hypoxia­induced apoptosis remains unclear. The present study investigated the potential mechanisms associated with IGF­1R­associated apoptosis under hypoxic conditions. Mouse embryonic fibroblasts exhibiting disruption or overexpression of IGF­1R (R­ cells and R+ cells) were used to examine the level of apoptosis, autophagy, and production of reactive oxygen species (ROS). The autophagy inhibitor 3­methyladenine was used to assess the effect of autophagy on ROS production and apoptosis under hypoxic conditions. A potential downstream signaling pathway involving phosphatidylinositol 3-kinase (PI3K)/threonine protein kinase B (Akt)/mammalian target of rapamycin (mTOR) was identifiedby western blot analysis. The results demonstrated that hypoxia induced apoptosis, increased ROS production, and promoted autophagy in a time­dependent manner relative to that observed under normoxia. R+ cells exhibited a lower percentage of apoptotic cells, lower ROS production, and higher levels of autophagy when compared to that of R- cells. In addition, inhibition of autophagy led to increased ROS production and a higher percentage of apoptotic cells in the two cell types. Furthermore, IGF­1R is related with PI3K/Akt/mTOR signaling pathway and enhanced autophagy-associated protein expression, which was verified following treatment with the PI3K inhibitor LY294002. These results indicated that IGF­1R may increase cell viability under hypoxic conditions by promoting autophagy and scavenging ROS production, which is closed with PI3K/Akt/mTOR signaling pathway.

Patients with multiple sclerosis show increased oxidative stress markers and somatic telomere length shortening.

Lipid peroxidation due to oxidative stress (OS) may play an important role in the pathogenesis of chronic systemic inflammatory diseases such as multiple sclerosis (MS). Telomeres, repeated sequences that cap chromosome ends, undergo shortening with each cycle of cell division, resulting in cellular senescence. Research regarding telomere shortening has provided novel insight into the pathogenesis of various diseases. We hypothesized that OS damage leads to inflammatory reactions, which subsequently shortens the telomere length in MS. We enrolled 59 patients with MS, and age- and gender-matched 60 healthy controls. We divided MS subjects into three groups matched for age and gender according to the severity of disability: relatively benign course (BMS), secondary progressive MS, and primary progressive MS (PPMS). We analyzed the telomere length in peripheral blood mononuclear cells and the 8-iso-PGF2α concentration in urine, a reliable and stable marker of lipid peroxidation in vivo. The data showed significant higher levels of urinary 8-iso-PGF2α in MS subjects than in the controls. The lag-time, which represents the direct measurement of the resistance of low-density lipoprotein to oxidation, was shorter in the PPMS subjects than in the groups. Compared to that observed in the controls, the mean telomere length was significantly shorter in the PPMS group, whereas no significant telomere shortening was found between the controls and other subjects. Our data suggest that a decreased telomere length and enhanced lipid peroxidation reflects the severest stage of MS.

Altered expression of genes associated with telomere maintenance and cell function of human vascular endothelial cell at elevated temperature.

The pathophysiological alterations of vascular endothelial cells induced by heat were studied. Human umbilical venous endothelial cells were cultured for 1 day at three different temperatures (37, 39, and 42 °C). The telomere lengths, the expressions of proteins associated with telomere length maintenance, apoptosis, heat shock, and vascular function were analyzed. The cell growth was not suppressed at 39 °C but suppressed at 42 °C. The mean telomere length did not change, whereas the telomere length distribution altered at 42 °C. Long telomere decreased and middle-sized telomere increased in the telomere length distribution at 42 °C. The telomerase activity did not show any heat-associated alterations. However, of the components of telomerase, telomerase reverse transcriptase was up-regulated along temperature elevation. In contrast, the expression level of RNA component TERC did not altered. Among the analyzed apoptosis-associated proteins, p21 was down-regulated and phosphorylated p53 was up-regulated. Heat shock proteins and NO synthase were up-regulated at 42 °C. These results suggested that induced growth suppression or cell senescence was induced by strong heat stress rather than mild one predominantly in cells bearing long telomeres with p53 activation, and simultaneously activated some telomere-associated factors, heat shock proteins, and NO synthesis probably for heat-resistant cell survival.

Changes in telomere length distribution in low-dose X-ray-irradiated human umbilical vein endothelial cells.

Ionizing radiation (IR) is known to be a cause of telomere dysfunction in tumor cells; however, very few studies have investigated X-ray-related changes in telomere length and the telomerase activity in normal human cells, such as umbilical vein endothelial cells (HUVECs). The loss of a few hundred base pairs from a shortened telomere has been shown to be important with respect to cellular senescence, although it may not be detected according to traditional mean telomere length [assessed as the terminal restriction fragment (TRF)] analyses. In the present study, a continuous time window from irradiation was selected to examine changes in the telomere length, including the mean TRF length, percentage of the telomere length, telomerase activity, apoptotic rate, and survival rate in HUVECs from the first day to the fourth day after the administration of a 0.5-Gy dose of irradiation. The mean TRF length in the irradiated HUVECs showed shorter telomere length in first 3 days, but they were not statistically significant. On the other hand, according to the percentage analysis of the telomere length, a decreasing tendency was noted in the longer telomere lengths (9.4-4.4 kb), with a significant increase in the shortest telomeres (4.4-2.3 kb) among the irradiated cells versus the controls from the first day to the third after irradiation; no significant differences were noted on the fourth day. These results suggest that the shortest telomeres are sensitive to the late stage of radiation damage. The proliferation of irradiated cells was suppressed after IR in contrast to the non-irradiated cells. The apoptotic rate was elevated initially both in IR- and non-IR-cells, but that of IR-cells was maintained at an elevated level thereafter in contrast to that of non-IR-cells decreasing promptly. Therefore, a 0.5-Gy dose of IR induces persistent apoptosis leading to an apparent growth arrest of the normal HUVECs.

Alterations in the telomere length distribution and the subtelomeric methylation status in human vascular endothelial cells under elevated temperature in culture condition.

Temperature-associated alteration in the telomere lengths of vascular endothelial cells has not been well investigated. Telomere length of human umbilical vein endothelial cells (HUVECs) cultured at a high temperature (42 °C) was analyzed. Here described are heat-associated phenotypical alterations of human vascular endothelial cell under prolonged heat stress in terms of telomere length, telomerase activity, and the expression of telomere associated proteins and heat shock proteins. The genomic DNA extracted from HUVECs cultured for 3 days under 42 °C was digested with methylation-sensitive and -insensitive isoschizomers and was subjected to genomic Southern blot probed with a telomere DNA fragment. Their telomere lengths and telomere length distributions were analyzed. Telomerase activity and the expressions of telomere-associated RNA, telomere-associated proteins (TERC, TERT, TRF1, and TRF2), and heat shock proteins (Hsp60, Hsp70, and Hsp90) were also analyzed. At 42 °C, cell growth was suppressed and the cell senescence rate was transiently elevated. A proportional decrease in the number of long telomeres was observed transiently at 42 °C. A trend of subtelomeric hypomethylation and lowered telomerase activity were observed at 42 °C after 3-day culture. The altered phenotypes on day 1 seemed reactive responses for cell protection to heat, and those on day 3 seemed exhausted reactions after 3-day culture. Maintained expression was observed in Hsps, TRF2, and TERC. These altered phenotypes might contribute to cell-survival under prolonged heat stress.

Analysis of telomere length and subtelomeric methylation of circulating leukocytes in women with Alzheimer's disease.

BACKGROUNDS AND AIMS: Telomere attrition proceeds with the aging process, and is also associated with aging disease conditions, such as Alzheimer's disease (AD). The aging process also affects subtelomeric methylation status. In the present study, the telomere length and the subtelomeric methylation status in female AD patients were analyzed to see how AD affects telomere structure. METHODS: Terminal restriction fragment length of 23 AD patients' peripheral leukocytes was analyzed with methylation sensitive- and insensitive-isoschizomer by Southern blot. RESULTS: AD patients were found to have normal mean telomere lengths (controls; 6.4 ± 0.9 kb, AD; 6.1 ± 0.8 kb, p = 0.131), a proportionally decreased number of the longest telomeres (>9.4 kb) (controls; 30.3 ± 7.9%, AD; 24.4 ± 8.3%, p = 0.013), increased medium-sized telomeres (controls; 51.7 ± 3.3%, AD 55.5 ± 6.4%, p = 0.015) and unchanged numbers of the shortest telomeres (<4.4 kb) (controls; 18.0 ± 7.8, AD; 20.2 ± 8.9%, p = 0.371) in their peripheral leukocytes. The subtelomeres of telomeres in the shortest range (<4.4 kb) were more methylated in AD subjects than in controls (controls; 0.21 ± 0.23, AD; 0.41 ± 0.26, p = 0.016). CONCLUSIONS: These results may indicate that AD contributes to the loss of cells bearing the shortest telomeres, with hypomethylation of subtelomeres occurring in addition to telomere attrition, resulting in an apparent normal mean telomere length in AD patients. The relatively high subtelomeric methylation status of the shortest telomeres in peripheral blood leukocytes may be a characteristic of AD. This report demonstrates that the epigenetic status of the telomeric region is affected by disease conditions.

Telomerase activity and telomere length distribution in vascular endothelial cells in a short-term culture under the presence of hydrogen peroxide.

AIM: The aim of this study was to assess the biological effects of oxidative stress on human vascular endothelial cells. METHODS: The telomeric changes and the alterations of the expression of telomere-associated proteins in human umbilical venous endothelial cells (HUVEC) cultured in the presence of hydrogen peroxide (H2 O2 ) were analyzed. RESULTS: During the culture, the cell growth rate decreased, whereas the telomerase activity of the surviving cells increased. As the H2 O2 level increased, long telomeres decreased proportionally, thus resulting in a telomere length distribution that was rich in short telomeres. These observations suggested that H2 O2 -affected endothelial cells bear telomeric features similar to those of aged cells. In contrast, the expression of telomere-associated proteins, TRF1 and TRF2, showed different changes. TRF1 increased in relation to H2 O2 concentration, whereas TRF2 showed no significant change. The surviving cells exposed to H2 O2 showed a H2 O2 -dose dependent increase in telomerase activity, whereas the telomere protein and RNA components were only elevated in low concentrations of H2 O2 . CONCLUSIONS: The increase in telomerase activity and TRF1 protein expression of vascular endothelial cell might show an aspect of cellular protective reaction against oxygen stress.

Different levels of hypoxia regulate telomere length and telomerase activity.

This study was designed to identify changes in telomere length and telomerase activity in human umbilical vein endothelial cells (HUVECs) exposed to various levels of hypoxia. Mild hypoxia (10%, 15% oxygen) increased telomere length, which did not appear to change under severe hypoxia (1% oxygen). Telomerase activity in HUVECs correlated inversely with oxygen concentration. Endothelial cell telomere elongation with telomerase activation in conditions of mild hypoxia was demonstrated in this study. High telomerase activity may contribute to hypoxia-related telomere elongation. The best cell growth and longest telomere length were observed at 10% O(2), and this percentage may therefore be the optimal level for maintaining vascular endothelial cells. In addition, elevated telomerase activity maintains telomere length within normal range in conditions of severe hypoxia (1% O(2)). The telomere length distribution in HUVECs under hypoxia seems to be regulated by a balance between telomere attrition by hypoxia and telomere elongation by enhanced telomerase activity acting on telomeres, perhaps in a telomere-length dependent manner.

The Subtelomere of Short Telomeres is Hypermethylated in Alzheimer's Disease.

Telomere shortening has been reported to be related to oxidative stress (OS) associated with the aging process and aging-associated diseases, including Alzheimer's disease (AD). We measured the methylated and non-methylated telomere lengths in the peripheral blood mononuclear cells of 34 AD patients and 49 healthy controls by a Southern blotting analysis, using methylation-sensitive and - insensitive restriction enzyme isoschizomers, MspI and HpaII. AD patients bore normal mean telomere lengths and had an unchanged distribution of the telomere length in peripheral leukocytes. However, the subtelomeres in the shortest telomeres were relatively more methylated in AD patients of both genders, compared with age-matched controls. We observed that the pathogenesis of AD was associated with the epigenetic condition of the subtelomere, but not on the overall telomere length and distribution. The relative elevation of subtelomeric methylation of short telomeres in peripheral blood leukocytes may be a characteristic of AD. This implies that leukocytes containing short telomeres with less methylated subtelomeres tend to be removed faster from the peripheral blood in AD patients.

Alteration of telomere length and subtelomeric methylation in human endothelial cell under different levels of hypoxia.

BACKGROUND AND AIMS: Hypoxia-associated changes of telomeric structure in cell cultures have been analyzed mainly in cancer cells, stem cells, or cells transduced with vectors containing the telomerase gene, but not in somatic cells. The stability of telomere structure has been reported to be associated with subtelomeric methylation status. However, there are no reports of epigenetic alterations of telomeric regions of human somatic cells under hypoxia. This study aims at detecting and analyzing the subtelomeric methylation status in human somatic cells cultured under hypoxia. METHODS: Mean telomere length and telomerase activity of human umbilical vein endothelial cells (HUVECs) cultured in hypoxic conditions were measured. Subtelomeric methylation status of these cells was assessed by genomic Southern blot with telomere DNA probe using methylation-sensitive and -insensitive isoschizomers, MspI and HpaII. RESULTS: The telomerase activity in HUVECs correlated inversely with the oxygen concentration. Mild hypoxia (10 or 15% oxygen) increased the telomere lengths, whereas the telomere lengths did not appear to change when <1% O(2). The subtelomere of the shortest telomere range was methylated the most at 1% O(2). CONCLUSIONS: Subtelomeric hypermethylation of short telomeres at 1% O(2) compared to milder hypoxia implied that the subtelomeric hypermethylation may yield telomere stability and favor the cell survival of short telomere-bearing cells.

Aging-associated alteration of telomere length and subtelomeric status in female patients with Parkinson's disease.

A telomere is a repetitive DNA structure at chromosomal ends that stabilizes the chromosome structure and prevents harmful end-to-end recombinations. The telomere length of somatic cells becomes shorter with aging because of the "end replication problem." This telomere shortening is accelerated by pathophysiological conditions including daily mental stress. Living with Parkinson's disease (PD) causes physical and mental stress; therefore, the authors hypothesized that the telomere length of somatic cells was shortened excessively in patients with PD. In order to detect PD-associated somatic telomeric alterations, the telomere length and subtelomeric methylation status of peripheral leukocytes of PD patients were assessed by Southern blotting, using methylation-sensitive and -insensitive isoschizomers. The results demonstrated that the peripheral leukocytes of Japanese female patients with PD bore fewer long telomeres and a proportional increase of hypomethylated subtelomeres in short telomeres in comparison with the healthy controls. This study indicates that with the neurodegeneration associated with PD, telomeric and subtelomeric structural alterations occur. These structural telomere alterations most likely occur secondary to the acceleration of aging-associated telomeric changes and the accelerated loss of cells bearing short telomeres.

Effect of vitamin E administration on the elevated oxygen stress and the telomeric and subtelomeric status in Alzheimer's disease.

BACKGROUND: Oxidative stress (OS) may be involved in the neurodegenerative process in Alzheimer's disease (AD). Telomeres, the repeated sequences that cap chromosome ends, undergo shortening with each cell division, are sensitive to OS, and serve as markers of a cell's replicative history. Telomere length shortening has been reported to relate to OS with aging process and aging-associated diseases, but the telomeric changes were not always identical, especially in change of telomere length distribution and subtelomeric methylation. The involvement of an OS-associated telomere change in the pathogenesis of AD has been discussed for decades, and the telomere length and telomerase activity were analyzed. However, other telomeric factors, such as the telomere distribution and subtelomeric methylation status, have not yet been analyzed. OBJECTIVE: The subtelomeric methylation status as well as the telomere length were studied in AD with an antioxidant vitamin in terms of OS. METHODS: We measured urinary 8-iso-PGF2α, a lipid-peroxidation product as an OS marker, and methylated and non-methylated telomere lengths in the peripheral blood mononuclear cells by Southern blotting in AD patients before and after vitamin E treatment. RESULTS: The level of urinary 8-iso-PGF2α was found to have increased in AD. Middle-ranged telomeres (4.4-9.4 kb) increased and the shortest telomeres (<4.4 kb) decreased in AD patients. Telomeres were more methylated in both long telomeres and in short telomeres in AD compared with the control. The oral administration of the antioxidant vitamin E in 400 mg/day for 6 months in AD patients partly reversed AD-associated alterations in OS marker levels. CONCLUSIONS: AD patients showed an elevated OS marker level, and vitamin E lowered the OS level. In comparison with controls, AD patients showed shorter telomere lengths. Cells with short and long telomeres bore relatively hypermethylated subtelomeres in AD patients. Aging-associated accumulation of cells bearing short telomeres was not observed in AD. These results imply that long telomeres with hypomethylation tend to shorten faster, and cells bearing short telomeres with hypomethylation tend to more easily enter into a senescent state under elevated OS stress in AD. However, no significant effect on the altered telomeric profiles in AD patients could be detected after a 6-month administration of vitamin E.