Hepatocyte growth factor enhances the ability of dental pulp stem cells to ameliorate atherosclerosis in apolipoprotein E-knockout mice.

BACKGROUND: Atherosclerosis (AS), a chronic inflammatory disease of blood vessels, is a major contributor to cardiovascular disease. Dental pulp stem cells (DPSCs) are capable of exerting immunomodulatory and anti-inflammatory effects by secreting cytokines and exosomes and are widely used to treat autoimmune and inflammation-related diseases. Hepatocyte growth factor (HGF) is a pleiotropic cytokine that plays a key role in many inflammatory and autoimmune diseases. AIM: To modify DPSCs with HGF (DPSC-HGF) and evaluate the therapeutic effect of DPSC-HGF on AS using an apolipoprotein E-knockout (ApoE-/-) mouse model and an in vitro cellular model. METHODS: ApoE-/- mice were fed with a high-fat diet (HFD) for 12 wk and injected with DPSC-HGF or Ad-Null modified DPSCs (DPSC-Null) through tail vein at weeks 4, 7, and 11, respectively, and the therapeutic efficacy and mechanisms were analyzed by histopathology, flow cytometry, lipid and glucose measurements, real-time reverse transcription polymerase chain reaction (RT-PCR), and enzyme-linked immunosorbent assay at the different time points of the experiment. An in vitro inflammatory cell model was established by using RAW264.7 cells and human aortic endothelial cells (HAOECs), and indirect co-cultured with supernatant of DPSC-Null (DPSC-Null-CM) or DPSC-HGF-CM, and the effect and mechanisms were analyzed by flow cytometry, RT-PCR and western blot. Nuclear factor-κB (NF-κB) activators and inhibitors were also used to validate the related signaling pathways. RESULTS: DPSC-Null and DPSC-HGF treatments decreased the area of atherosclerotic plaques and reduced the expression of inflammatory factors, and the percentage of macrophages in the aorta, and DPSC-HGF treatment had more pronounced effects. DPSCs treatment had no effect on serum lipoprotein levels. The FACS results showed that DPSCs treatment reduced the percentages of monocytes, neutrophils, and M1 macrophages in the peripheral blood and spleen. DPSC-Null-CM and DPSC-HGF-CM reduced adhesion molecule expression in tumor necrosis factor-α stimulated HAOECs and regulated M1 polarization and inflammatory factor expression in lipopolysaccharide-induced RAW264.7 cells by inhibiting the NF-κB signaling pathway. CONCLUSION: This study suggested that DPSC-HGF could more effectively ameliorate AS in ApoE-/- mice on a HFD, and could be of greater value in stem cell-based treatments for AS.

A biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties and accelerating osseointegration in spinal fusion.

Objectives: Spinal fusion is a widely employed treatment of patients with degenerative disc disease, in which a cage is used to replace the disc for spinal fusion. But it often fails for insufficient mechanical strength and poor osseointegration. Here, we designed a polyether-ether-ketone (PEEK)/tantalum (Ta) composite cage with a biomimetic gradient porous micro-structure, simultaneously enhancing mechanical properties and accelerating osseointegration in spinal fusion. Materials and methods: In the study, based on the mechanical performances of PEEK and osteogenic potential of Ta, and the three-dimensional (3D) structures of cuttlebone and vertebra, the cages were respectively 3D printed by pure PEEK, PEEK with 5 wt% Ta (PEEK/Ta-5), PEEK with 10 wt% Ta (PEEK/Ta-10) and PEEK with 15 wt% Ta (PEEK/Ta-15), then verified in vitro and in sheep cervical fusion model systematically. Results: Vertebral Gyroid structure PEEK/Ta-15 cage exhibited superior mechanical properties than Cuttlebone-like structure PEEK/Ta-15 cage, closer to the cervical vertebra. Furthermore, PEEK/Ta-15 cage with higher Ta microparticles in PEEK provided a biomimetic gradient porous micro-structure with higher surface energy, guiding cell biological behavior, promoting new bone penetration, and accelerating osseointegration in vivo. Conclusion: In conclusion, the study designed a biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties, accelerating osseointegration and forming an anatomical lock in the fusion segment through composites, mechanical efficiency, surface extension, and pores.

Dynamic Spine Hyperflexion Is Related to Vertebral Compression Fractures in Postmenopausal Women.

OBJECTIVE: Previous studies on osteoporotic vertebral fractures are usually based on the neutral posture of spine; however, the fractures are usually associated with the flexion posture of spine. Therefore, we aimed to ascertain the relationship between vertebral compression fractures and thoracolumbar hyperflexion Cobb angles (TLHCobb) and determine the clinical cut-off of the TLHCobb angle. METHODS: In this retrospective case-control study, TLHCobbs were collected from 154 postmenopausal women (67.45 ± 6.68 years) with vertebral compression fractures (study group) and 310 postmenopausal women (66.57 ± 8.22 years) without vertebral compression fractures (control group) from June 2017 to July 2019. Demographic data, clinical data, and quantitative computed tomography (QCT) findings were compared between the groups. Chi-squared tests, unpaired t-tests, and Mann Whitney U were used to assess the group characteristics and proportions. Logistic regression was used to examine the association between vertebral compression fractures and TLHCobb. The cut-off of the TLHCobb was determined by ROC curve and Youden's index. RESULTS: Fracture prevalence was higher in the higher TLHCobb study group than that in the control group [OR = 2.81 (2.15-3.67)] after adjusting for age, BMI, and QCT findings. TLHCobbs at and >20.05° were associated with an increased fracture prevalence and ORs of 2.79 (1.82-4.27) and 4.83 (3.24-7.20), respectively. TLHCobb, disk height (semiquantitative grading score) and QCT values differed between the study and control groups (p < 0.001 for all three). There were no significant differences in body mass index (BMI), or coronal TLCobb between the two groups. CONCLUSION: There was an association between the prevalence of vertebral compression fractures and TLHCobbs in postmenopausal women, and a TLHCobb > 20.05° can be an indicator of vertebral fracture.

Mid-term outcomes after total hip arthroplasty in 106 Crowe II/III hips: different hip center positions.

BACKGROUND: Under the obvious acetabular superolateral bone defect of Crowe II/III hips, this study aimed to investigate the difference in surgical technique of different hip center positions from the surgical data and clinical outcomes. METHODS: From July 2007 to December 2016, 87 patients (106 Crowe II/III hips) consecutively received total hip arthroplasty (THA). The minimum follow-up time was 5 years. The mean limb length discrepancy was 1.97 ± 1.81 cm. Twenty-four hips had surgical histories. The patients were divided into three groups according to the acetabular prosthesis positions, depending on the Crowe classification, respectively, group 1 (Crowe I), group 2 (Crowe II) and group 3 (Crowe III). The surgical data and clinical results were used to evaluate the outcome of different surgical techniques of different hip center positions, including surgical time, blood loss, blood transfusion, number of osteotomy hips, osteotomy length, the distribution of prothesis, postoperative inpatient days, Harris hip scores, Visual Analogue Scale (VAS), Back Pain Function Scale (BPFS) and complications. RESULTS: The mean follow-up time was 8.93 ± 2.55 years. Nineteen hips performed intraoperative osteotomy. From group 1 to group 3, the mean osteotomy length were 0.53 ± 1.11 cm, 0.05 ± 0.22 cm, and 0.00 ± 0.00 cm, respectively (p = 0.083); the surgical time were 142.57 ± 57.94 min, 118.4 ± 41.22 min, and 120.00 ± 84.85 min, respectively (p = 0.324); the blood loss were 498.21 ± 368.53 mL, 333.33 ± 167.62 mL, and 350.00 ± 212.13 mL, respectively (p = 0.255); the blood transfusion were 288.48 ± 381.68 mL, 128.00 ± 235.17 mL, and 385.00 ± 219.20 mL, respectively (p = 0.199); the postoperative inpatient days were 7.95 ± 4.42 d, 7.47 ± 4.29 d, and 6.50 ± 0.71 d, respectively (p = 0.831). Among the groups, the distribution of acetabular prosthesis, acetabular liner, acetabular prosthesis sizes, femoral head sizes and femoral prothesis distal sizes were not significantly different (p > 0.05). Only the distribution of femoral prosthesis was significantly different (p = 0.046); the Harris, VAS, BPFS, and the distribution of complications were not significantly different (p > 0.05). CONCLUSIONS: We provided a framework to guide decision-making in Crowe II/III hips for surgeons: the surgical technique of different hip center positions was stable and had good outcomes, but the acetabular prothesis position and femoral prothesis should be determined according to the intraoperative situation. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Hydroxytyrosol Ameliorates Intervertebral Disc Degeneration and Neuropathic Pain by Reducing Oxidative Stress and Inflammation.

Low back pain (LBP) seriously affects human quality of life. Intervertebral disc degeneration (IVDD) is the main pathological factor that leads to LBP, but the pathological mechanism underlying IVDD has not been fully elucidated. Neuropathic pain caused by IVDD is an important pathological factor affecting people's daily lives. Therefore, it is very important to identify therapeutic drugs to ameliorate IVDD and secondary neuropathic pain. Hydroxytyrosol (HT) is a natural compound derived from olive leaves and oil and has anti-inflammatory, antioxidant, and antitumor activities and other properties. In this study, TNF-α-stimulated human nucleus pulposus cells (HNPCs) were used to simulate the local inflammatory microenvironment observed in IVDD in vitro to explore the role of HT in alleviating various pathological processes associated with IVDD. A rat needle puncture model was used to further explore the role of HT in alleviating IVDD. Lipopolysaccharide (LPS) was used to stimulate microglia in vitro to comprehensively explore the role of HT in alleviating neuropathic pain, and a rat model involving chronic compression of the dorsal root ganglion (CCD) was established to simulate the neuropathic pain caused by IVDD. This study suggests that HT reduces the expression of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome, a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4) and matrix metalloproteinase-13 (MMP-13); inhibits the production of mitochondrial reactive oxygen species (ROS); and maintains mitochondrial homeostasis. Thus, HT appears to reduce the rate of apoptosis and mitigate the loss of major intervertebral disc components by inhibiting the nuclear factor kappa-B (NF-κB) signaling pathway. Moreover, HT inhibited the secretion of COX-2, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1ß, and iNOS and activation of the NLRP3 inflammasome in microglia by inhibiting the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and extracellular regulated protein kinase (ERK) signaling pathways. In conclusion, HT plays a protective role against IVDD and secondary neuropathic pain by inhibiting the NF-κB, PI3K/AKT, and ERK signaling pathways.

Are Both Preoperative Full-Spine 3Dimensional Computed Tomography Scans and X-Ray Films Necessary for Patients with Ankylosing Spondylitis Kyphosis?

OBJECTIVE: This study is aimed to investigate whether both pre-operative full-spine 3Dimensional computed tomography scan (3D CT) and X-ray film were necessary for patients with severe ankylosing spondylitis (AS) kyphosis deformity. METHODS: The research objects were selected from the inpatients with AS in our hospital from 2017 to 2019. A total of 42 patients were included in the study. On both the synthesized 2Dimensional (2D) lateral radiograph and X-ray film, the globe kyphosis (GK), the lumber lordosis (LL), the thoracolumbar kyphosis (TLK) and the thoracic kyphosis (TK) were measured. And the angle seventh thoracic vertebra (T7), the angle twelfth thoracic vertebra (T12) and the angle third lumber vertebra (L3) were also measured. Two researchers with professional medical education were randomly selected to perform the measurement method and record the measurement data. Two researchers independently completed, recorded, and evaluated the accuracy and consistency of the measurement data. This study used intraclass correlation coefficient (ICC) to analyze the synthesized 2D lateral radiograph and general X-ray film of 42 subjects by two researchers, in order to evaluate the consistency of data measurement results between the examiners. Through the comparison of the above parameters that the GK, LL, TLK, TK, angle T7, angle T12 and angle L3, the evaluation was made both pre-operative full-spine 3D CT and X-ray film were necessary for patients with severe AS kyphosis deformity. RESULTS: There was no significant difference between the GK, LL, TLK, TK, angle T7, angle T12, angle L3 on the synthesized 2D lateral radiograph and that on X-ray film (P = 0.240, 0.324, 0.199, 0.095, 0.421, 0.087, 0.478). Agreement two researchers was excellent with ICC of the GK, LL, TLK, TK, angle T7, angle T12, angle L3 (0.977, 0.969, 0.986, 0.945, 0.947, 0.915, 0.857) on the synthesized 2D lateral radiograph. The Bland-Altman plot results that the measurement results of examiners are reliable and stable. CONCLUSION: By estimating the degree of spinal sagittal imbalance and measuring the Cobb angle, we can see that full-length spine radiographs of the patients are unnecessary for patients with severe AS kyphosis deformity who will or have undergone preoperative spine 3D CT.

Dental pulp stem cell-derived exosomes suppress M1 macrophage polarization through the ROS-MAPK-NFκB P65 signaling pathway after spinal cord injury.

Stem cell-derived exosomes have recently been regarded as potential drugs for treating spinal cord injury (SCI) by reducing reactive oxygen species (ROS) and suppressing M1 macrophage polarization. However, the roles of ROS and exosomes in the process of M1 macrophage polarization are not known. Herein, we demonstrated that ROS can induce M1 macrophage polarization and have a concentration-dependent effect. ROS can induce M1 macrophage polarization through the MAPK-NFκB P65 signaling pathway. Dental pulp stem cell (DPSC)-derived exosomes can reduce macrophage M1 polarization through the ROS-MAPK-NFκB P65 signaling pathway in treating SCI. This study suggested that DPSC-derived exosomes might be a potential drug for treating SCI. Disruption of the cycle between ROS and M1 macrophage polarization might also be a potential effective treatment by reducing secondary damage.

[Treatment of chronic osteomyelitis of rabbit with liposomal gentamicin-impregnated allogeneic cortical bone].

OBJECTIVE: It is difficult to treat chronic osteomyelitis due to the formation of the Staphylococcus aureus biofilms. Liposomal gentamicin-impregnated allogeneic cortical bone can inhibit the formation of the Staphylococcus aureus biofilms. To explore the treatment of chronic osteomyelitis of rabbit by liposomal gentamicin-impregnated allogeneic cortical bone. METHODS: The liposomal gentamicin, liposomal gentamicin-impregnated allogeneic cortical bone and gentamicin-impregnated allogeneic cortical bone were produced. Then the chronic Staphylococcus aureus osteomyelitis models of rabbit were made in left lower limbs of 40 6-month-old rabbits and the right lower limbs were used as controls. After 2 weeks, the observations of gross and X-ray were done. Four rabbits died within 10 days after the models were made and other 36 rabbits were divided into 6 groups: group A (no antibiotics), group B (intravenous injection of gentamicin), group C (intravenous injection of liposomal gentamicin), group D (implantation of gentamicin-impregnated allogeneic cortical bone), group E (implantation of liposomal gentamicin-impregnated allogeneic cortical bone), and group F (implantation of allogeneic cortical bone). After 2 weeks of treatment, the bacterial culture, X-ray and HE staining were done. RESULTS: The chronic Staphylococcus aureus osteomyelitis model of rabbit was made successfully. The X-ray showed dissolution of bone and periosteal reaction in groups A, B, C, and F, and no obvious dissolution of bone and periosteal reaction in groups D and E. The Norden scores were (2.5 +/- 0.3), (2.1 +/- 0.2), (1.5 +/- 0.3), (1.5 +/- 0.2), (0.9 +/- 0.3), and (2.7 +/- 0.3) points in groups A-F, respectively; showing significant differences between group A and groups B-E (P < 0.05), between groups B, E, F and other groups (P < 0.05). The results of blood and marrow cultures for Staphylococcus aureus were positive in groups A and F, and negative in other 4 groups; the results of bone marrow culture for Staphylococcus aureus were positive in 6 rabbits of group B, 4 rabbits of group C and 3 rabbits of group D; and the results were negative in group E. HE staining showed: in groups A and F, abscess and dead bone formed, and no new bone formation were observed; in groups B and C, different degrees of neutrophil accumulation was seen; in group D, some neutrophil accumulation occurred, and osteoprogenitor cells and osteoclasts were seen around implanted bone; and in group E, no neutrophil accumulation was observed, a lot of granulation tissues formed, and osteoprogenitor cells and osteoclasts were seen around implanted bone. CONCLUSION: Implantation of liposomal gentamicin-impregnated allogeneic cortical bone has remarkably better effect in treating chronic osteomyelitis than intravenous injection of liposomal gentamicin and implantation of gentamicin-impregnated allogeneic cortical bone.

[Histopathological changes of three kinds of bone grafts in vivo].

OBJECTIVE: To evaluate the tissue response induced by three kinds of bone transplantation materials implanted in rat so as to provide proper evidence for their clinical application. METHODS: Thirty-six healthy mature Sprague-Dawley rat, weighing from 229 g to 358 g, were randomly assigned to groups A and B (n=18). Three kinds of materials were implanted into muscles of rats. Calcium sulfate (CS) granular preparations and allogeneic demineralized bone matrix (DBM) were transplanted into the left (group A1) and right (group A2) thigh muscle pouches of group A. Respectively, whereas xenogenic DBM were transplanted into the left (group B1) thigh muscle pouches of group B and the right (group B2) sites were taken as control without implant. The samples (n=6) were collected to make the observation of gross and histology and to analyze histological score after 2, 4, and 6 weeks. RESULTS: The gross observation: implanted materials were gradually absorbed at late stage in group A1. No obvious degradation and absorption, but fibrosis of tissues were observed in group A2 and B1. The inflammatory reactions were more severe in groups A2 and B1. In group B2, only the changes of scar were seen at operative site. The histological observation: no obvious inflammatory reactions were seen in group A1, CS were gradually absorbed and completely absorbed at 6 weeks, while fibrosis of tissues increased at late stage. Inflammatory reactions in group A2 and group B1 were alleviated gradually, no obvious absorption and degradation were observed. The different two DBM could induce granulation tissues and bone formation at different sites and secondary fibrosis with no obvious immune response was observed. In group B2, there was an increase in collagen fiber density and angiogenesis at late stage. The scores of inflammatory infiltration were significantly higher in groups A2, B1 than in groups A1, B2 (P < 0.05), and the scores of fibrosis was larger in groups A1, A2 and B1 than in group B2 (P < 0.05). CONCLUSION: CS has rapid dissolution and good biocompatibility. It is a good replaceable packing materials of bone defects in some upper limb's or acute bone fracture. Both of two DBM have biocompatibility and osteoinductive potential, which dissolution are very slow. Due to these capacity, they can be served as an ideal materials in treatment of lower limb's bone defect and nonunion.