Dataset Information

Relative telomere length and oxidative DNA damage in hypertrophic ligamentum flavum of lumbar spinal stenosis.

ABSTRACT: Background:Lumbar spinal stenosis (LSS) is a common cause of low back pain with degenerative spinal change in older adults. Telomeres are repetitive nucleoprotein DNA sequences of TTAGGG at the ends of chromosomes. Oxidative stress originates from an imbalance in pro-oxidant and antioxidant homeostasis that results in the production of reactive oxygen species (ROS). The purpose of this study was to investigate relative telomere length (RTL) and oxidative DNA damage in ligamentum flavum (LF) tissue from LSS patients. Methods:Forty-eight patients with LSS participated in this study. Genomic DNA from non-hypertrophic and hypertrophic LF tissue were analyzed by real-time polymerase chain reaction for relative telomere length (RTL). 8-hydroxy 2'-deoxygaunosine (8-OHdG) levels were determined by using enzyme-linked immunosorbent assay. We cultivated LF fibroblast cells from patients in different ages (61, 66, and 77 years). After each cultivation cycle, we examined RTL and senescence-associated ?-galactosidase (SA-?-gal) expression. Results:The hypertrophic LF had significantly lower RTL than non-hypertrophic LF (P = 0.04). The levels of 8-OHdG were significantly higher in hypertrophic LF compared to non-hypertrophic LF (P = 0.02). With advancing cell culture passage, the number of cells in each passage was significantly lower in hypertrophic LF fibroblast cells than non-hypertrophic LF fibroblast cells. When evaluated with SA-?-gal staining, all senescent LF fibroblast cells were observed at earlier passages in hypertrophic LF compared with non-hypertrophic LF fibroblast cells. Discussion:Our results showed that patients with LSS displayed an accelerated RTL shortening and high oxidative stress in hypertrophic LF. These findings implied that telomere shortening and oxidative stress may play roles in the pathogenesis of hypertrophic LF in lumbar spinal stenosis.

SUBMITTER: Dechsupa S

PROVIDER: S-EPMC6087619 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Relative telomere length and oxidative DNA damage in hypertrophic ligamentum flavum of lumbar spinal stenosis.

Dechsupa Sinsuda S Yingsakmongkol Wicharn W Limthongkul Worawat W Singhatanadgige Weerasak W Honsawek Sittisak S

PeerJ 20180809

<h4>Background</h4>Lumbar spinal stenosis (LSS) is a common cause of low back pain with degenerative spinal change in older adults. Telomeres are repetitive nucleoprotein DNA sequences of TTAGGG at the ends of chromosomes. Oxidative stress originates from an imbalance in pro-oxidant and antioxidant homeostasis that results in the production of reactive oxygen species (ROS). The purpose of this study was to investigate relative telomere length (RTL) and oxidative DNA damage in ligamentum flavum ( ...[more]

PMID: 30123710

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Project description:Chronic inflammation and subsequent fibrosis induced by mechanical stress play an important role in ligamentum flavum (LF) hypertrophy and degeneration in patients with lumbar spinal canal stenosis (LSCS). Angiopoietin-like protein 2 (Angptl2) is a chronic inflammatory mediator induced under various pathological conditions and increases the expression of TGF-β1, which is a well-characterized mediator in LF hypertrophy. We investigated whether Angptl2 is induced by mechanical stress, and whether it contributes to LF hypertrophy and degeneration by activating the TGF-β1 signaling cascade. In this study, we investigated human LF tissue and LF fibroblasts isolated from patients who underwent lumbar surgery. We found that Angptl2 was abundantly expressed in fibroblasts of hypertrophied LF tissues at both the mRNA and protein levels. This expression was not only positively correlated with LF thickness and degeneration but also positively correlated with lumbar segmental motion. Our in vitro experiments with fibroblasts from hypertrophied LF tissue revealed that mechanical stretching stress increases the expression and secretion of Angptl2 via activation of calcineurin/NFAT pathways. In hypertrophied LF tissue, expression of TGF-β1 mRNA was also increased and TGF-β1/Smad signaling was activated. Angptl2 expression in LF tissue was positively correlated with the expression of TGF-β1 mRNA, suggesting cooperation between Angptl2 and TGF-β1 in the pathogenesis of LF hypertrophy. In vitro experiments revealed that Angptl2 increased levels of TGF-β1 and its receptors, and also activated TGF-β1/Smad signaling. Mechanical stretching stress increased TGF-β1 mRNA expression, which was partially attenuated by treatment with a calcineurin/NFAT inhibitor or Angptl2 siRNA, indicating that induction of TGF-β1 expression by mechanical stretching stress is partially mediated by Angptl2. We conclude that expression of Angptl2 induced by mechanical stress in LF fibroblasts promotes LF tissue degeneration by activation of TGF-β1/Smad signaling, which results in LF hypertrophy in patients with LSCS.

Project description:ObjectiveTo explore the main causes of hypertrophied ligamentum flavum (HLF) and the possibility of using bipedal standing mouse model to simulate the pathological changes in human HLF.MethodsThirty-two 8-week-old C57BL/6 male mice were randomly assigned to the experimental group (n = 16) and control group (n = 16). In the experimental group, mice were induced to adopt a bipedal standing posture by their hydrophobia. The experimental mice were maintained bipedal standing for 8 h a day with an interval of 2 h to consume food and water. The control mice were placed in a similar environment without bipedal standing. Eight 18-month-old C57BL/6 male mice were compared to evaluate the LF degeneration due to aging factor. Three-dimensional (3D) reconstruction and finite element models were carried out to analyze the stress and strain distribution of the mouse LF in sprawling and bipedal standing postures. Hematoxylin and Eosin (HE), Verhoeff-Van Gieson (VVG), and immunohistochemistry (IHC) staining were used to evaluate the LF degeneration of mice and humans. RT-qPCR and immunofluorescence analysis were used to evaluate the expressions of fibrosis-related factors and inflammatory cytokines of COL1A1, COL3A1, α-SMA, MMP2, IL-1β, and COX-2.ResultsThe von Mises stress (8.85 × 10-2 MPa) and maximum principal strain (6.64 × 10-1 ) in LF were increased 4944 and 7703 times, respectively, in bipedal standing mice. HE staining showed that the mouse LF area was greater in the bipedal standing 10-week-old group ([10.01 ± 2.93] × 104 μm2 ) than that in the control group ([3.76 ± 1.87] × 104 μm2 ) and 18-month-old aged group ([6.09 ± 2.70] × 104 μm2 ). VVG staining showed that the HLF of mice (3.23 ± 0.58) and humans (2.23 ± 0.31) had a similar loss of elastic fibers and an increase in collagen fibers. The cell density was higher during the process of HLF in mice (39.63 ± 4.81) and humans (23.25 ± 2.05). IHC staining showed that the number of α-SMA positive cells were significantly increased in HLF of mice (1.63 ± 0.74) and humans (3.50 ± 1.85). The expressions of inflammatory cytokines and fibrosis-related factors of COL1A1, COL3A1, α-SMA, MMP2, IL-1β, and COX-2 were consistently higher in bipedal standing group than the control group.ConclusionOur study suggests that 3D finite element models can help analyze the abnormal stress and strain distributions of LF in modeling mice. Mechanical stress is the main cause of hypertrophied ligamentum flavum compared to aging. The bipedal standing mice model can reflect the pathological characteristics of human HLF. The bipedal standing mice model can provide a standardized condition to elucidate the molecular mechanisms of mechanical stress-induced HLF in vivo.

Project description:Purpose:To develop a self-administered diagnostic screening questionnaire for lumbar spinal stenosis (LSS) consisting of items with high content validity and to investigate the diagnostic value of the questionnaire and the items. Patients and Methods:A self-reported diagnostic LSS screening questionnaire was developed based on items from the existing literature describing key symptoms of LSS. The screening questionnaire (index test) was to be tested in a cohort of patients with persistent lumbar and/or leg pain recruited from a Danish publicly funded outpatient secondary care spine clinic with clinicians performing the reference test. However, to avoid unnecessary collection of data if the screening questionnaire proved to be of limited value, a case-control design was incorporated into the cohort design including an interim analysis. Additional cases for the case-control study were recruited at two Danish publicly funded spine surgery departments. Prevalence, sensitivity, specificity and diagnostic odds ratio (OR) were calculated for each individual item, and AUC (area under the curve) was calculated to examine the performance of the full questionnaire. Results:A 13-item Danish questionnaire was developed and tested in 153 cases and 230 controls. The interim analysis was not in favour of continuing the cohort study, and therefore, only results from the case-control study are reported. There was a positive association for all items except the presence of back pain. However, the association was only moderate with ORs up to 3.3. When testing the performance of the whole questionnaire, an AUC of 0.72 was reached with a specificity of 20% for a fixed sensitivity of 95%. Conclusion:The items were associated with LSS and therefore have some potential to identify LSS patients. However, the association was not strong enough to provide sufficient accuracy for a diagnostic tool. Additional dimensions of symptoms of LSS need identification to obtain a reliable questionnaire for screening purposes.

Dataset Information

Relative telomere length and oxidative DNA damage in hypertrophic ligamentum flavum of lumbar spinal stenosis.

Publications

Relative telomere length and oxidative DNA damage in hypertrophic ligamentum flavum of lumbar spinal stenosis.

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