Bingfang Zeng

Improvement of blood flow, expression of nitric oxide, and vascular endothelial growth factor by low-energy shockwave therapy in random-pattern skin flap model.

Extracorporeal shock wave therapy (ESWT) can improve flap survival, but its mechanism remains unclear. In this study, we aim to investigate whether ESWT can improve blood flow in ischemic skin flaps and the possible mechanism. Cranially based random-pattern flap (3 × 10 cm) model was established, and its ischemic portion was treated with or without ESWT at 0.09 mJ/mm2 with 750 impulses (1.5 Hz), immediately after operation. Survival area, blood flow, vessel distribution, microvessel density, and expression of nitric oxide and vascular endothelial growth factor were evaluated at 1, 3, and 10 days postoperatively. The results showed that blood perfusion, expression of nitric oxide and vascular endothelial growth factor, vasodilatation of pre-existing vessels at early postoperative stage, neovascularization at late stage, and flap survival were all significantly promoted in treatment group. In conclusion, ESWT can improve skin flap surviving rate through enhanced vasodilatation at early postoperative stage and neovascularization at late stage via modulation of angio-active factors expression.

Hidden blood loss after total hip arthroplasty.

A prospective study was carried out to analyze the characteristics of hidden blood loss after total hip arthroplasty (THA) in a series of 1232 patients. The method of deducting the observed perioperative blood loss from the calculated total blood loss based on hematocrit changes was used to calculate the hidden blood loss of each patient. The reinfused and transfused bloods were also considered. We found that the amount of hidden blood loss after THA was much larger than we observed perioperatively and significantly different between differently diagnosed patients. We concluded that THA can cause a large amount of hidden blood loss, which should be monitored carefully. Retaining and repairing the articular capsule is recommended during the operation, which can significantly decrease hidden blood loss.

The linker region of Smad2 mediates TGF-β-dependent ERK2-induced collagen synthesis

Transforming growth factor (TGF)-beta1 can cause fibrosis diseases by enhancing production of collagen. However, the intracellular signaling mechanism for TGF-beta1 stimulation of this process has not been fully elucidated. The present study focused on this mechanism and the cross-talk between the MAPK and Smad pathways. Extracellular signal-regulated kinase (ERK)2 ablation by a small interfering RNA led to marked inhibition of TGF-beta1-induced collagen synthesis and enhanced phosphorylation of the Smad2 linker site in NIH/3T3 fibroblast cells. However, ERK1 ablation had minimal effects. Ablation of either ERK2 or ERK1 had no effect on the phosphorylation of the Smad2 C-terminal site. Furthermore, a Smad2 mutant with reduced phosphorylation of the Smad2 linker site inhibited TGF-beta1-induced collagen synthesis. These results indicate that ERK2, rather than ERK1, plays a predominantly positive role in TGF-beta1-induced collagen synthesis, and that ERK2 enhances collagen synthesis, at least partially, through activation of the Smad2 linker site.

Experience with the distally based sural neurofasciocutaneous flap supplied by the terminal perforator of peroneal vessels for ankle and foot reconstruction.

The distally based sural fasciocutaneous flap has been proved an excellent option for coverage of the soft tissue defects of the lower third of the leg, ankle, and foot. In this article, we reported on a series of foot and ankle reconstructions with a distally based sural neurofasciocutaneous flap supplied by the terminal perforating branch of the peroneal artery. The vascular pedicle of the flap includes the terminal perforator branch of the peroneal artery and concomitant veins. The pivot point is approximately 5 cm above the tip of lateral malleolus. Fifteen patients with soft tissue defects of the foot and/or ankle underwent the procedures of reconstruction. The flaps were designed with the size measuring 8 × 9 cm to 13 × 31 cm. Thirteen flaps survived completely and 2 with partial or margin necrosis. Our experience has demonstrated that this sural flap with a thin perforator pedicle can be easily rotated, used for coverage of a large tissue defect including the forefoot area, and provide a good texture match and contour for the recipient area.

Experimental repair of segmental bone defects in rabbits by angiopoietin-1 gene transfected MSCs seeded on porous β-TCP scaffolds.

Segmental bone defect repair remains a clinical and experimental challenge in tissue engineering with increasing focus on angiogenesis in the bone substitutes. The objective of this study was to investigate the osteogenic effects of angiopoietin-1 (Ang-1) gene transfected bone marrow-derived mesenchymal stem cells (MSCs) seeded on porous β-TCP scaffolds. This bone substitute (experimental group) and MSCs/β-TCP compounds (control group) were implanted into 15 mm segmental bone defects of the radii of 30 New Zealand white rabbits, with platelet-rich plasma injected at the same time. Bone regeneration and angiogenesis were assessed by Scanning electron microscope (SEM), X-ray, histology, immunohistology, and biomechanical outcome measurements made on the 2nd, 4th, 8th, and 12th week after the operation. In vitro, the amount of proliferation and differentiation of Ang-1 gene transfected MSCs was found to be gross increased than that of the control groups. In vivo, a significantly increased amount of new bone formation accompanied by active capillary vasculature regeneration was observed in the pores of the scaffolds which had been seeded with Ang-1 gene transfected MSCs, as compared with the control groups. The biomechanical test confirmed the failure load of new born bone was close to normal bone. These results suggest that transfer of gene encoding Ang-1 to MSCs increases their osteogenic properties by enhancing capillary regeneration, thus providing a rich blood supply for new bone formation in segmental bone defects.

Beneficial effect of autologous transplantation of endothelial progenitor cells on steroid-induced femoral head osteonecrosis in rabbits.

Femoral head osteonecrosis (ON) is a serious complication of steroid administration. We examined whether implantation of autologous bone marrow-derived endothelial progenitor cells (EPCs) can augment neovascularization and bone regeneration in steroid-induced osteonecrosis of the femoral head. Forty 12-week-old male New-Zealand white rabbits were divided into group I (left untreated, n = 12), group II (core decompression, n = 12), and group III (core decompression + autologous EPCs implantation, n = 16) after receiving an established inductive protocol for inducing steroid-associated ON. Four weeks later, these rabbits were euthanized, bilateral femora were dissected for Micro-CT-based microangiography to assess vascularization, and then the osteonecrotic changes and repair processes were examined histopathologically. Quantitative analysis showed that new vessel formation in group III was significantly greater compared with other groups at 4 weeks after treatment. The histologic and histomorphometric analyses revealed that the new bone volume was significantly higher in group III than in groups I and II 4 weeks after treatment. A combination of EPCs and core decompression enhances the neovascularization and bone regeneration in rabbit steroid-induced femoral head ON. Local implantation of EPCs may provide a novel and effective therapeutic option for early corticosteroid-induced ON.

Combined medialis pedis and medial plantar fasciocutaneous flaps based on the medial plantar pedicle for reconstruction of complex soft tissue defects in the hand

The reconstruction of complex soft tissue defects in hands remains a difficult challenge in reconstructive surgery. In this report, we introduce a combined medialis pedis and medial plantar fasciocutaneous flaps supplied by the lateral and medial branches of the medial plantar artery, which allows a one‐stage reconstruction of multiple soft tissue defects in hand. Three combined medialis pedis and medial plantar fasciocutaneous flaps were transferred for repair of the soft tissue defects including palmar and dorsal areas of hand, thumb pulp, and the dorsum of index finger in three patients. All three flaps survived uneventfully with coverage matching the texture and color of the recipients. The donor sites healed without complication. The experience from these cases proves that the combined medialis pedis and medial plantar fasciocutaneous flaps based on the medial plantar pedicle would be a valuable alternative for the reconstruction of complex soft tissue defects in the hand.

The mechanical benefit of medial support screws in locking plating of proximal humerus fractures.

Background The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs) in the locking proximal humeral plate for treating proximal humerus fractures. Methods Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed. Results Constructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (P<0.0001). When the proximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P≤0.0207). Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture. Conclusions Anatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure.

Risk factors for articular cartilage lesions in symptomatic discoid lateral meniscus.

PURPOSE To investigate risk factors related to articular cartilage lesions in discoid lateral meniscus (DLM) and to analyze the possible mechanisms associated with articular cartilage lesions. METHODS From October 2004 to April 2008, 103 knees in 97 patients with DLM confirmed by arthroscopy were operated on at our clinical center. Among them, 16 knees were accompanied by articular cartilage injury. Data on risk factors, including patient age, traumatic history, DLM type, presence or absence of tear, symptomatic duration, and meniscal shape, were analyzed to investigate the relation with articular cartilage lesion by logistic regression analysis. RESULTS Only symptomatic duration and meniscal shape had a significant relation with articular cartilage lesion. Symptomatic duration and meniscal shape can be regarded as risk factors, and their odds ratios were 4.983 (P < .01) and 5.356 (P < .05), respectively. CONCLUSIONS Long symptomatic duration (>6 months) and asymmetrical shape of DLM were more frequently related to articular cartilage lesions than other factors. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Co-culturing mesenchymal stem cells from bone marrow and periosteum enhances osteogenesis and neovascularization of tissue-engineered bone.

Mesenchymal stem cells (MSCs) isolated from bone marrow and periosteum are often used as cellular sources for bone tissue engineering. This study showed that co‐cultured human bone marrow stem cells (hBMSCs) and periosteal‐derived stem cells (hPCs) resulted in a synergistic effect on osteogenic differentiation both in vitro and in vivo. Compared to hBMSCs and hPCs, co‐culturing MSCs showed abundant mineralization, robust calcium deposition, steadily increasing ALP activity, and upgraded mRNA expression of osteogenic specific genes (COL1A1, BMP‐2, osteopontin, osteocalcin) in vitro. Eight weeks after implantation of cellular β‐TCP scaffolds in immunodeficient mice, similar synergistic effects were confirmed during in vivo evaluation of total new bone formation, mature bone formation, and neovascularization. Based on these findings, the use of co‐cultured hBMSCs and hPCs can be recommended as a promising new approach for bone tissue engineering applications. Copyright