Experimental Model of Intervertebral Disk Mediated Postoperative Epidural Fibrosis

The Influence of Exosomes Derived from Mesenchymal Stem Cells on the Development of Fibrosis In Vitro

We studied the effect of exosomes derived from mesenchymal stem cells on the synthesis of collagen I and α-smooth muscle actin (α-SMA) by rat fibroblast culture. Exosomes were isolated from the verified culture of mesenchymal stem cells and also verified. Fibrosis was modeled using a fibroblast culture supplemented with recombinant TGF-β1 (5 ng/ml) and immunocytochemical analysis of the expression of collagen I and α-SMA markers was carried out. After 6-day incubation, the expression of the studied markers increased in comparison with the control. Addition of exosomes to the fibroblast culture reduced the production of collagen and SMA, which allows considering exosomes as a promising drug for the treatment of pathologies associated with fibrosis.

High-Frequency Bipolar Coagulation Limits Epidural Fibrosis in Lumbar Microdiscectomy

BACKGROUND AND AIM

We propose a vast study to examine the effect of high-frequency bipolar coagulation used in the operating room to prevent the development of epidural fibrosis after lumbar microdiscectomy.

MATERIALS AND METHODS

A total of 1004 participants were divided into two groups: no high-frequency bipolar coagulation (NC group) and high-frequency bipolar coagulation (C group). Postoperative epidural fibrosis, infection rates, reoperation status, and dural injury complications during the operation were recorded.

RESULTS

Considering the epidural fibrosis rates of the two groups, epidural fibrosis was seen in 10.6% of the patients in the NC group. In contrast, it was seen in only 6.2% of the patients in the C group.

CONCLUSION

The complication of epidural fibrosis that develops after lumbar microsurgery operations both impairs patient comfort and brings with it the complications of reoperation. After performing hemostasis with bipolar, coagulating the annulus may effectively reduce epidural fibrosis and prevent reoperation.

miR‑519d‑3p promotes TGFβ/Smad mediated postoperative epidural scar formation via suppression of BAMBI

To investigate the role of microRNA (miR)‑519d‑3p in postoperative epidural scar formation and its regulation of the bone morphogenetic protein and activin membrane‑bound inhibitor (BAMBI), miR‑519d‑3p and BAMBI expression levels in the lumbar disc of patients who had undergone laminectomy were detected with reverse transcription‑quantitative polymerase chain reaction and western blotting. The results demonstrated that miR‑519d‑3p expression was significantly increased, whereas BAMBI expression was sharply reduced in the lumbar discs of patients suffering from epidural scars. Subsequently, the miR‑519d‑3p mimic was transfected into primary fibroblasts isolated from epidural scar tissues. Flow cytometric and Cell Countin Kit‑8 analyses indicated that overexpression of miR‑519d‑3p promoted the proliferation of fibroblasts, the production of tumor necrosis factor‑α and interleukin (IL)‑1α, and the expression of type I collagen (col I), α‑smooth muscle actin (α‑SMA) and fibronectin (FN). Downregulation of miR‑519d‑3p by the miR‑519d‑3p antagomir transfection had the opposite effect. Bioinformatics and luciferase reporter gene analyses demonstrated that BAMBI is a target gene of miR‑519d‑3p: miR‑519d‑3p directly binds to the 3'‑untranslated region of BAMBI mRNA and suppressed BAMBI protein expression. Finally, the pcDNA‑BAMBI vector and BAMBI small interfering RNA were respectively transfected into primary fibroblasts to overexpress and knockdown the BAMBI gene. It was demonstrated that BAMBI overexpression suppressed fibroblast proliferation, TNF‑α and IL‑1α production, and the expression of col I, α‑SMA and FN proteins, whereas, BAMBI knockdown had the opposite effect. In conclusion, it was noted that BAMBI is a target of miR‑519d‑3p and miR‑519d‑3p promotes transforming growth factor β/mothers against decapentaplegic homolog 9‑mediated postoperative epidural scar formation via suppression of BAMBI.

Inflammation by activated macrophage-like THP-1 cells increases human dura mater cell adhesion with alteration of integrin α2 β1 and matrix metalloproteinase

This study was designed to investigate (i) extracellular matrix to specify adhesive substrates to human dura mater cell (hDMC); (ii) the alteration on adhesion-related molecules in hDMC; and (iii) secreted matrix metalloproteinases (MMPs) linked with extracellular matrix remodeling after exposure to inflammation. The hDMC was cultured from human dura mater tissue, and the studies were performed with hDMC after co-culturing with macrophage like THP-1 cells (Mϕ). The adhesion of co-cultured hDMC through collagen I increased 6.4-fold and through collagen IV increased 5.0-fold compared with the adhesion of naïve cells (p < 0.001). Integrin subtype α₂ β₁ expression was increased 6.3-fold (p < 0.001) and α₁ expression was decreased 2.0-fold (p < 0.001) in the co-cultured cells compared with the naïve cells. Co-culturing induced significant increases in MMP-1 (13.9-fold, p < 0.01), MMP-3 (7.6-fold, p < 0.01), and VEGF (VEGF: 3.8-fold, p < 0.05) expression and decreases in MMP-9 (0.1-fold, p < 0.01) compared with the sum of naïve hDMC and Mϕ values. Increased hDMC adhesion under inflammatory conditions is caused by an increased cellular affinity for collagen I and IV mediated by increased hDMC levels of integrin subtype α₂ β₁ and environmental MMP-1, -3 and decreased MMP-9. Selective integrin subtype α₂ β₁ inhibition assay showed 37.8% and 35.7% reduction in adhesion of co-cultured hDMC to collagen I (p < 0.001) and IV (p = 0.057), respectively. The present study provides insight into the pathological conditions related to dura mater adhesion in inflammation. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-11, 2019.

Impact of sorafenib on epidural fibrosis: An immunohistochemical study

AIM

To determine if sorafenib, an antineoplastic agent, could prevent the development of spinal epidural fibrosis (EF).

METHODS

The study used CD105 and osteopontin antibodies in an immunohistochemical approach to quantify EF that occurred as a consequence of laminectomy in rats. Wistar albino rats (n = 16) were divided into two groups: control (L1-2 level laminectomy only) and sorafenib treatment (L1-2 level laminectomy + topical sorafenib). The animals were euthanatized after 6 wk, and the EF tissues were examined for histopathological changes after immunohistochemical staining. The EF grades were assigned to the tissues, and the treatment and control groups were compared.

RESULTS

The EF thickness, inflammatory cell density, and arachnoid adherences determined by light microscopy were significantly higher in the control group compared to the sorafenib-treated group. Based on fibrosis scores, the extent of EF in the treatment group was significantly lower than in the controls. Immunohistochemical staining for CD105 to identify microvessels revealed that the EF grades based on vessel count were significantly lower in the treatment group. Staining for osteopontin did not show any significant differences between the groups in terms of the extent of EF. The staging of EF based on vascular counts observed after immunohistochemical staining for CD105, but not for osteopontin, was compatible with conventional staging methods. Neither toxic effects on tissues nor systemic side effects were observed with the use of sorafenib.

CONCLUSION

Local administration of sorafenib significantly reduced post-laminectomy EF. Decreased neovascularization in spinal tissue may be due to the sorafenib-induced inhibition of vascular endothelial growth factor.

Toll-Like Receptor 9 Promotes Survival in SERCA2a KO Heart Failure Mice

Aim. Inflammation is important in heart failure (HF). The role of the immune receptor toll-like receptor 9 (TLR9) in HF is not understood and not investigated in diastolic HF. We investigated the role of TLR9 in a murine diastolic HF model caused by cardiomyocyte SERCA2a excision. Methods and Results. We crossed SERCA2a KO and TLR9 KO mice to generate four mouse lines. Tamoxifen-induced cardiomyocyte SERCA2a gene excision was carried out in mice, causing diastolic HF. After 7.6 weeks, cardiac functions and dimensions were analyzed by echocardiography and heart tissues were processed. HF mice depleted of TLR9 demonstrated reduced survival compared to SERC2a KO mice, with a median life expectancy of 58 days compared to 63 days. Both HF groups displayed increased left atrium size, lung weight, fetal gene expressions, monocyte/macrophage infiltration, and fibrosis. However, there were no significant differences between the groups. Conclusion. In mice with SERCA2a KO-induced diastolic HF, the absence of TLR9 reduced median life expectancy. The cause remains elusive, as all investigated HF parameters were unaltered. Still, these findings support a salutary role of TLR9 in some subsets of HF conditions and underline the importance for future studies on the mechanisms of TLR9 in diastolic HF.