LncAABR07053481 inhibits bone marrow mesenchymal stem cell apoptosis and promotes repair following steroid-induced avascular necrosis.

The osteonecrotic area of steroid-induced avascular necrosis of the femoral head (SANFH) is a hypoxic microenvironment that leads to apoptosis of transplanted bone marrow mesenchymal stem cells (BMSCs). However, the underlying mechanism remains unclear. Here, we explore the mechanism of hypoxic-induced apoptosis of BMSCs, and use the mechanism to improve the transplantation efficacy of BMSCs. Our results show that the long non-coding RNA AABR07053481 (LncAABR07053481) is downregulated in BMSCs and closely related to the degree of hypoxia. Overexpression of LncAABR07053481 could increase the survival rate of BMSCs. Further exploration of the downstream target gene indicates that LncAABR07053481 acts as a molecular "sponge" of miR-664-2-5p to relieve the silencing effect of miR-664-2-5p on the target gene Notch1. Importantly, the survival rate of BMSCs overexpressing LncAABR07053481 is significantly improved after transplantation, and the repair effect of BMSCs in the osteonecrotic area is also improved. This study reveal the mechanism by which LncAABR07053481 inhibits hypoxia-induced apoptosis of BMSCs by regulating the miR-664-2-5p/Notch1 pathway and its therapeutic effect on SANFH.

High throughput analysis to identify key gene molecules that inhibit adipogenic differentiation and promote osteogenic differentiation of human mesenchymal stem cells.

The present study investigated the key genes, which cause switch from adipogenic to osteogenic differentiation of human mesenchymal stem cells (hMSCs). The transcriptomic profile of hMSCs samples were collected from Array Express database. Differential expression network was constructed by calculating the Pearson's correlation coefficient and ranked according to their topological features. The top 5% genes with degree ≥2 were selected as ego genes. Following the KEGG pathway enrichment analysis and the relevant miRNAs prediction, the miRNA-mRNA-pathway networks were constructed by combining the miRNA-mRNA pairs and mRNA-pathway pairs together. In total, we obtained 84, 119, 94 and 97 ego-genes in B, BI, BT and BTI groups, and DLGAP5, DLGAP5, NUSAP1 and NDC80 were the ego-genes with the highest z-score of each group, respectively. Beginning from each ego-gene, we identified 2 significant ego-modules with gene size ≥4 in group BI, and the ego-genes were PBK and NCOA3, respectively. Through KEGG pathway analysis, we found that most of the pathways enriched by ego-genes were associated with gene replication and repair, and cell proliferation. According to the miRNA prediction results, we found that some of the predicted miRNAs have been validated to be the regulatory miRNAs of these corresponding mRNAs. Finally we constructed a miRNA-mRNA-pathway network by integrating the miRNA-mRNA and mRNA-pathway pairs together. The constructed network gives us a more comprehensive understanding of the mechanism of osteogenic differentiation of hMSCs.

Elevated Risk of Infections after Spinal Cord Surgery in Relation to Preoperative Pressure Ulcers: a Follow-up Study.

Factors associated with infections after spinal cord surgery were not fully understood. This study aimed to evaluate whether preoperative pressure ulcers was a risk factor of infections after spinal cord operation. A 1:1 matched follow-up study was performed in a tertiary referral center in southwest China between 2010 and 2015. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression analysis. A total of 334 patients with spinal cord surgery were recruited (167 patients with preoperative pressure ulcers and 167 patients without preoperative pressure ulcers). Participants previously exposed to pressure ulcers had an elevated risk of infections post spinal cord operation including surgical site infection (RR: 2.3, 95% CI: 1.1, 4.7), pneumonia (RR: 2.4, 95% CI: 1.1,5.3), urinary tract infection (RR: 2.8, 95% CI: 1.1, 7.3), any kinds of postoperative infections (RR: 3.4, 95% CI: 2.1, 5.6) and 30-day postoperative hospitalization for infections (RR: 2.6, 95% CI: 1.1, 6.0). The associations between preoperative pressure ulcers in stage III to IV and postoperative infections were also pronounced, but towards null in stage I to II. The study showed an increased risk of infections after spinal cord surgery in patients with preoperative pressure ulcers, indicative of an urgent need for monitoring postoperative infections and medical treatment for patients with pressure sores.

Role of FGF-2 Transfected Bone Marrow Mesenchymal Stem Cells in Engineered Bone Tissue for Repair of Avascular Necrosis of Femoral Head in Rabbits.

BACKGROUND/AIMS: Avascular necrosis of the femoral head (ANFH) is the focus and difficulty of orthopedic diseases. Recently, tissue engineering bone for this disease has shown a good therapeutic effect. The aim of the present study was to investigate the therapeutic effect of basic fibroblast growth factor (FGF-2) as cytokines transfected bone marrow mesenchymal stem cells (BMSCs) in constructing tissue-engineered bone for avascular necrosis of the femoral head. METHODS: The FGF-2 gene overexpressed lentivirus-transfected rBMSCs with xenogeneic antigen-extracted cancellous bone (XACB) to construct tissue engineered bone, and the model of early avascular necrosis of the femoral head was established by lipopolysaccharide (LPS) combined with hormone. The models were randomly divided into five groups: A (control), B (XACB), C (XACB+rBMSCs), D (XACB+rBMSCs+Lv-GFP), and E (XACB+rBMSCs+Lv-FGF-2/GFP) groups. The therapeutic effect of the tissue engineered bone for the avascular necrosis of the femoral head was evaluated by gross anatomy, X-ray examination, immunohistochemistry and H&E staining. RESULTS: The FGF-2 gene was transfected into rBMSCs (Multiplicity of infection [MOI] = 100) by lentivirus, and its efficiency was above 95%. The rBMSCs were successfully transfected overexpressing FGF-2 by qPCR and western blot. After tissue engineering bone implantation, X-ray examination and gross specimen observation revealed that the repair area in the E group was > 80% at six weeks, the defect was completely repaired at 12 weeks, and osteogenesis was stronger, when compared with the other groups. For the X-ray score, vascular area density and new bone formation area were higher, when compared with the other groups, and the difference was statistically significant (P< 0.05). CONCLUSION: FGF-2 gene overexpression lentivirus transfection BMSCs combined with XACB to construct tissue engineered bone can effectively promote vascular regeneration, and improve the repair effect of avascular necrosis of the femoral head.

Adenovirus-Mediated Expression of BMP-2 and BFGF in Bone Marrow Mesenchymal Stem Cells Combined with Demineralized Bone Matrix For Repair of Femoral Head Osteonecrosis in Beagle Dogs.

BACKGROUND: This study investigated the effect of using adenovirus-mediated expression of bone morphogenetic protein 2 (Ad-BMP-2) and basic fibroblast growth factor (bFGF) in bone marrow mesenchymal stem cells (BMSCs) in combination with a demineralized bone matrix (DBM) to repair osteonecrosis of the femoral head (ONFH) in Beagle dogs. METHODS: A total of 30 Beagle dogs were selected for the isolation of BMSCs, which were cultured and transfected with the recombinant adenovirus vector Ad-BMP2-bFGF-GFP (carrying BMP-2 and bFGF) or a control adenovirus plasmid (encoding green fluorescent protein (Ad-GFP)). The expression of the transfected BMP-2 and bFGF proteins was detected by Western blotting. After transfection, the BMSCs were induced to undergo osteoblastic differentiation. The DBM was prepared to construct a DBM/BMSC complex. Beagle models of canine femoral head defects and necrosis were established and divided into control, DBM, DBM/BMSC, vector Ad-BMP2-bFGF-GFP and Ad-GFP groups. The composite graft was then implanted, and new bone morphology was visualized via X-ray at 3, 6 and 12 weeks after the operation. Hematoxylin and eosin (HE) staining and Masson's trichrome staining were used to identify new bone formation. Immunohistochemistry was performed to calculate the density of new blood vessels. The compressive and bending strength of the BMSCs was evaluated at 12 weeks after the operation. RESULTS: BMSCs were successfully isolated. The protein expression of BMP-2 and bFGF was significantly higher in the Ad-BMP-2/bFGF group than the normal and Ad-GFP groups. Compared with the control group, at 12 weeks after the operation, the DBM, DBM/BMSC, vector Ad-BMP2-bFGF-GFP and Ad-GFP groups showed a larger area of new bone, higher X-ray scores, greater neovascularization density, and increased compressive and bending strength. The most significant modifications occurred in thevector Ad-BMP2-bFGF-GFP group. CONCLUSION: The results indicate that the use of Ad-BMP-2/bFGF-modified BMSCs in conjunction with DBM could successfully repair ONFH in a dog model by promoting bone formation and angiogenesis.

MicroRNA-34a alleviates steroid-induced avascular necrosis of femoral head by targeting Tgif2 through OPG/RANK/RANKL signaling pathway.

The study aims to investigate the effect of microRNA-34a (miR-34a) targeting Tgif2 on steroid-induced avascular necrosis of femoral head (SANFH) by regulating OPG/RANK/RANKL signaling pathway. SD rats were divided into normal control and model (RNAKL rat models) groups. The model group was further assigned into model control, negative control, miR-34a mimics and miR-34a inhibitors groups. QRT-PCR was applied to detect miR-34a, Tgif2, OPG, RANK and RNAKL mRNA expressions. Femoral head tissues were collected for Micro-CT scanning and HE staining. QRT-PCR and Western blotting were used to detect expressions of miR-34a, Tgif2, OPG, RANK, RANKL and Runx2, OPN and OC in bone tissues. Dual-luciferase reporter gene assay was used to testify the target relationship between miR-34a and Tgif2. Compared with the normal control group, the model group showed increased Tgif2, RANK and RANKL mRNA expressions, but decreased miR-34a and OPG mRNA expressions. Tgif2 mRNA expression was negatively correlated with miR-34a and OPG mRNA expressions. Micro-CT showed cystic degeneration of femoral head, with decreased bone volume/total volume (BV/TV), bone surface area/bone volume and trabecular number in the model control group compared with the normal control group. Compared with the model control group, the miR-34a mimics group showed increased BV/TV and trabecular thickness and Runx2, OPN and OC expressions, while the parameters decreased in the miR-34a inhibitors group. Compared with the normal control group, the other groups showed increased Tgif2, RANK and RANKL expressions but decreased miR-34a and OPG expressions. Compared with the model control group, Tgif2, RANK and RANKL expressions decreased and miR-34a and OPG expressions increased in the miR-34a mimics group, while the miR-34a inhibitors group had a reverse trend in contrast to the miR-34a mimics group. Tgif2 is a target gene of miR-34a. In conclusion, miR-34a can alleviate SANFH through targeting Tgif2 and further regulating OPG/RANK/RANKL signaling pathway. Impact statement miR-34a can alleviate SANFH through targeting Tgif2 and further regulating OPG/RANK/RANKL signaling pathway, which can be used as a new theoretical basis for SANFH treatment.