Hypoxia-treated adipose mesenchymal stem cell-derived exosomes attenuate lumbar facet joint osteoarthritis.

BACKGROUND: Lumbar facet joint osteoarthritis (LFJ OA) is a common disease, and there is still a lack of effective disease-modifying therapies. Our aim was to determine the therapeutic effect of hypoxia-treated adipose mesenchymal stem cell (ADSC)-derived exosomes (Hypo-ADSC-Exos) on the protective effect against LFJ OA. METHODS: The protective effect of Hypo-ADSC-Exos against LFJ OA was examined in lumbar spinal instability (LSI)-induced LFJ OA models. Spinal pain behavioural assessments and CGRP (Calcitonin Gene-Related Peptide positive) immunofluorescence were evaluated. Cartilage degradation and subchondral bone remodelling were assessed by histological methods, immunohistochemistry, synchrotron radiation-Fourier transform infrared spectroscopy (SR-FTIR), and 3D X-ray microscope scanning. RESULTS: Hypoxia enhanced the protective effect of ADSC-Exos on LFJ OA. Specifically, tail vein injection of Hypo-ADSC-Exos protected articular cartilage from degradation, as demonstrated by lower FJ OA scores of articular cartilage and less proteoglycan loss in lumbar facet joint (LFJ) cartilage than in the ADSC-Exo group, and these parameters were significantly improved compared to those in the PBS group. In addition, the levels and distribution of collagen and proteoglycan in LFJ cartilage were increased in the Hypo-ADSC-Exo group compared to the ADSC-Exo or PBS group by SR-FTIR. Furthermore, Hypo-ADSC-Exos normalized uncoupled bone remodelling and aberrant H-type vessel formation in subchondral bone and effectively reduced symptomatic spinal pain caused by LFJ OA in mice compared with those in the ADSC-Exo or PBS group. CONCLUSIONS: Our results show that hypoxia is an effective method to improve the therapeutic effect of ADSC-Exos on ameliorating spinal pain and LFJ OA progression.

Quantitative biochemical phenotypic heterogeneity of senescent macrophage at a single cell level by Synchrotron Radiation Fourier Transform Infrared Microspectroscopy.

Macrophage senescence plays an important role in pathophysiological process of age-related diseases such as atherosclerosis, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and lung cancer. After macrophage senescence, the biochemical phenotypes related to biological functions showed great heterogeneity. However, the biochemical phenotype and phenotypic heterogeneity of senescent macrophage has not been fully understood. Exploring the phenotype of biochemical substances in senescent macrophage will be helpful for understanding the function of senescent macrophage and finding out the potential mechanism between immune macrophage senescence and age-related diseases. In this study, we employed SR-FTIR microspectroscopy to detect the biochemical phenotype and phenotypic heterogeneity of single macrophage. The whole infrared spectra of senescent macrophages shifted, indicating biochemical substance changes within senescent macrophages. PCA and intercellular Euclidean distance statistical analysis based on specific spectra regions revealed dynamic changes of lipids and proteins during macrophage senescence. This proved that SR-FTIR microspectroscopy is an effective tool to detect the single cell biochemical phenotype transformation and phenotypic heterogeneity during macrophage senescence. It is of great significance to provide an evaluation method or clue for the study of cellular functions related to intracellular biochemical substances.

Lauromacrogol foam injection under ultrasonic guidance for pediatric lip venous malformations.

OBJECTIVE: To evaluate the efficacy and safety of lauromacrogol foam sclerotherapy in the treatment of children with lip venous malformation. METHODS: Fifty-two children (27 males and 25 females) aged from 6 months to 17 years with lip VM who underwent lauromacrogol foam injection with ultrasonic guidance from July 2018 to December 2020 in our hospital were retrospectively recruited for this study. All the children were examined by MRI, ultrasound, blood routine and coagulation before operation. We were guided by ultrasound to locate the blood flow area (nests), injecting lauromacrogol foam to fill the venous malformation. The follow-up time was 14.31 ± 5.96 (6-24) months. Follow-up items include clinical manifestations, imaging data, efficacy and complications. RESULTS: This group of children was treated 3-5 times, an average of 4 times/case. The total effective rate was 90.38%. Pain in 4 cases, fever in 4 cases, infection in 2 cases, ulcer in 1 case. There were no serious complications such as cardiopulmonary accident. CONCLUSION: Ultrasound guiding foam sclerotherapy with lauromacrogol is effective and safe for children with lip venous malformation.

A comparative study of one-stage posterior unilateral limited laminectomy vs. bilateral laminectomy debridement and bone grafting fusion combined with internal fixation for the treatment of aged patients with single-segment spinal tuberculosis.

STUDY DESIGN: This is a retrospective study. BACKGROUND: To assess and compare the clinical outcomes of posterior unilateral limited laminectomy (ULL) or bilateral laminectomy (BL) debridement and bone grafting fusion combined with internal fixation among aged patients with single-segment thoracic and lumbar tuberculosis (SST/LTB). MATERIALS AND METHODS: We performed a retrospective study on aged patients (age > 65 years old) with SST/LTB from January 2010 to October 2018. We reviewed 36 aged patients who were treated with BL and 31 aged patients treated with ULL. All participants had undergone and finished a three-year follow-up. The outcomes were evaluated by the improvement of neurological function, correction Cobb angle, bone fusion time, and back pain, as well as operative time, blood loss, hospital stay, and postoperative complications. RESULTS: The operative time, blood loss volume, and incidence of complications in group B were significantly less than those in group A (P < 0.01). The postoperative kyphotic angle in both groups was reduced significantly compared to the preoperative status (P < 0.01). The percentage of neurological improvement was 92.9% in group A and 90.9% in group B. All patients achieved solid bone fusion after surgery. At three-year follow-up, the angle loss in group B was significantly less than that in group A (P < 0.01); Furthermore, patients in group B had a lower average visual analog scale score of back pain and Oswestry Disability Index score than patients in group A (P < 0.05). CONCLUSIONS: For aged patients with SST/LTB, ULL is a safer and more effective surgical treatment than BL.

Posterior limited unilateral fenestration approach for treating patients with single-segment thoracic and lumbar tuberculosis.

BACKGROUND: Posterior limited unilateral fenestration approach is extensively used in the treatment of many spinal diseases. But whether it is suitable for spinal tuberculosis (TB) is rarely reported. Hence, the current study evaluated the feasibility and efficacy of the posterior limited unilateral fenestration (PLUF) debridement, bone grafting fusion, and instrumentation to treat single-segment thoracic and lumbar TB. METHODS: Eighty-three patients (45 male and 38 female) aged 17-79 years old with the single-segment thoracic and lumbar TB who underwent PLUF debridement, bone grafting fusion, and instrumentation from our hospital were recruited for this study. The operation time, blood loss volume, postoperative complication rate, kyphotic Cobb angle, neurological functional improvement defined by the American Spinal Injury Association (ASIA) classification, the visual analogue scale (VAS) score, and the bone fusion time were utilized for assessing the clinical feasibility and efficacy. RESULTS: The average follow-up time was 46.9 ± 13.1 (24-72) months. At the last follow-up, the mean kyphotic Cobb angle was significantly reduced from preoperative 23.0° ± 15.3° to postoperative 8.3° ± 11.0° (p < 0.001). Based on the ASIA classification, 89.2% (33 out of 37) patients with preoperative neurological impairment indicated good neurological improvement after the surgery. The VAS pain score significantly decreased from preoperative 6.9 ± 1.1 to 1.3 ± 0.7 3 months after operation (p < 0.001). All the patients achieved solid bony fusion within 13 months of surgery. CONCLUSIONS: For patients with single-segment thoracic and lumbar TB, PLUF debridement, bone grafting fusion, and instrumentation are a feasible and effective surgical treatment.

Quantitative biochemical phenotypic heterogeneity of macrophages after myelin debris phagocytosis at a single cell level by synchrotron radiation fourier transform infrared microspectroscopy.

During the immuno-inflammatory pathophysiological process of spinal cord injury, traumatic brain injury, and ischemic stroke, macrophages play an important role in phagocytizing and clearing degenerated myelin debris. After phagocytizing myelin debris, the biochemical phenotypes related to the biological function of macrophages show vast heterogeneity; however, it is not fully understood. Detecting biochemical changes after myelin debris phagocytosis by macrophages at a single-cell level is helpful to characterize phenotypic and functional heterogeneity. In this study, based on the cell model of myelin debris phagocytosis by macrophages in vitro, the biochemical changes in macrophages were investigated using Synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy. Infrared spectrum fluctuations, principal component analysis, and cell-to-cell Euclidean distance statistical analysis of specific spectrum regions revealed dynamic and significant changes in proteins and lipids within macrophages after myelin debris phagocytosis. Thus, SR-FTIR microspectroscopy is a powerful identification toolkit for exploring biochemical phenotype heterogeneity transformation that may be of great importance to providing an evaluation strategy for studying cell functions related to cellular substance distribution and metabolism.

Identification of Cathepsin B as a Therapeutic Target for Ferroptosis of Macrophage after Spinal Cord Injury.

Hemorrhage and immune cell infiltration are the main pathological features of spinal cord injury (SCI). Excessive iron deposition is caused by leaking hemosiderin which may over-activate ferroptosis pathways, resulting in lipid peroxidation and mitochondrial dysfunction in cells. Inhibiting ferroptosis after SCI has been shown to aid functional recovery. However, the essential genes involved in cellular ferroptosis following SCI are still unknown. Here we show that Ctsb is a statistical significance gene by collecting multiple transcriptomic profiles and identifying differentially expressed ferroptosis-related genes, which are abundantly expressed in myeloid cells after SCI and widely distributed at the epicenter of the injury. The expression score of ferroptosis, calculated by ferroptosis driver/suppressor genes, was high in macrophages. Furthermore, we discovered that inhibiting cathepsin B (CTSB), specifically with a small-molecule drug, CA-074-methyl ester (CA-074-me), reduced lipid peroxidation and mitochondrial dysfunction in macrophages. We also found that alternatively activated M2-polarized macrophages are more susceptible to hemin-induced ferroptosis. Consequently, CA-074-me could reduce ferroptosis, induce M2 macrophage polarization, and promote the neurological function recovery of mice after SCI. Our study comprehensively analyzed the ferroptosis after SCI from the perspective of multiple transcriptomes and provided a novel molecular target for SCI treatment.

Metformin promotes angiogenesis and functional recovery in aged mice after spinal cord injury by adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway.

Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury. However, its effect on spinal cord injury in aged mice remains unclear. Considering the essential role of angiogenesis during the regeneration process, we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells, thereby promoting microvascular regeneration in aged mice after spinal cord injury. In this study, we established young and aged mouse models of contusive spinal cord injury using a modified Allen method. We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord. Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro. Furthermore, intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord, thereby improving neurological function. The role of metformin was reversed by compound C, an adenosine monophosphate-activated protein kinase inhibitor, both in vivo and in vitro, suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury. These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway, thereby improving the neurological function of aged mice after spinal cord injury.

Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Accelerate Functional Recovery After Spinal Cord Injury by Promoting the Phagocytosis of Macrophages to Clean Myelin Debris.

Macrophage phagocytosis contributes predominantly to processing central nervous system (CNS) debris and further facilitates neurological function restoration after CNS injury. The aims of this study were to evaluate the effect of bone marrow mesenchymal stem cells (BMSC)-derived exosomes (BMSC-Exos) on the phagocytic capability of macrophages to clear myelin debris and to investigate the underlying molecular mechanism during the spinal cord injury (SCI) process. This work reveals that monocyte-derived macrophages (MDMs) infiltrating into the SCI site could efficiently engulf myelin debris and process phagocytic material. However, the phagocytic ability of macrophages to clear tissue debris is compromised after SCI. The administration of BMSC-Exos as an approach for SCI treatment could rescue macrophage normal function by improving the phagocytic capability of myelin debris internalization, which is beneficial for SCI repair, as evidenced by better axon regrowth and increased hindlimb locomotor functional recovery in a rodent model. Examination of macrophage treatment with BMSC-Exos revealed that BMSC-Exos could promote the capacity of macrophages to phagocytose myelin debris in vitro and could create a regenerative microenvironment for axon regrowth. In addition, we confirmed that BMSC-Exo treatment resulted in improved phagocytosis of engulfed myelin debris by promoting the expression of macrophage receptor with collagenous structure (MARCO) in macrophages. The inhibition of MARCO with PolyG (a MARCO antagonist) impaired the effect of BMSC-Exos on the phagocytic capacity of macrophages and resulted in compromised myelin clearance at the lesion site, leading to further tissue damage and impaired functional healing after SCI. In conclusion, these data indicated that targeting the phagocytic ability of macrophages may have therapeutic potential for the improvement in functional healing after SCI. The administration of BMSC-Exos as a cell-free immune therapy strategy has wide application prospects for SCI treatment.

Utx Regulates the NF-κB Signaling Pathway of Natural Stem Cells to Modulate Macrophage Migration during Spinal Cord Injury.

Neural stem cells (NSCs) play vital roles in the homeostasis of neurological function. Ubiquitously transcribed tetratricopeptide repeat, X chromosome (UTX) is an important regulator of stem cell phenotypes. In our current study, we aimed to investigate whether the conditional knockout of UTX on neural stem cells alters macrophage assembly in response to spinal cord injury (SCI). Conditional knockout Utx of NSC (Utx-KO) mice was used to generate SCI models by the modified Allen method. We reported that neurological function and scar hyperplasia significantly improved in Utx-KO mice after SCI, accompanied by significantly reduced assembly of macrophages. With a 45-fold pathway array and Western blot, we found that Utx-KO could significantly inhibit NF-κB signaling activation and promote the synthesis and secretion of macrophage migration inhibitory factor (MIF) in NSCs. Administration of the selective NF-κB p65 activator betulinic acid and the selective MIF inhibitor ISO-1 confirmed that the activation of NF-κB p65 phosphorylation or inhibition of MIF could eliminate the benefits of Utx-KO in SCI, such as inhibition of macrophage aggregation and reduction in scar proliferation. This study confirmed that UTX in NSCs could alter macrophage migration and improve neurological function recovery after SCI in mice.

Nucleosome-binding protein HMGN2 exhibits antitumor activity in human SaO2 and U2-OS osteosarcoma cell lines.

High mobility group N (HMGNs) are members of the high mobility group protein family, and are involved in the development and progression of several tumors. HMGN1 and HMGN5 were previously shown to be associated with the bioactivities of osteosarcoma. However, the effects and molecular mechanisms of HMGN2 on osteosarcoma progression remain to be determined. In order to characterize the endogenous expression of HMGN2 in osteosarcoma cell lines, RT-PCR and western blot analysis were performed. Recombinant HMGN2 lentivirus was used to infect the osteosarcoma cell lines with relatively low HMGN2 expression to determine the functional relevance of HMGN2 overexpression in osteosarcoma cell growth and migration in vitro and in vivo, and to investigate the expression levels of Ki-67, PCNA, cyclin D1 and cyclin E. The results showed that osteosarcoma cell proliferation and migration were significantly reduced by HMGN2, as indicated by cell count and wound-healing assays. Cell apoptosis was markedly induced and HMGN2 increased the sensitivity to chemotherapy. When HMGN2 expression was enhanced, the expression of cyclin D1 and PCNA was downregulated in osteosarcoma cells. In addition, the tumor volumes in SaO2 and U2-OS subcutaneous nude mouse models treated with HMGN2 lentivirus were significantly decreased as compared to those of the GFP group. These results suggested that the enhanced expression of HMGN2 in osteosarcoma cells by HMGN2 lentivirus, exerts inhibitory effects on growth and migration of osteosarcoma cells.