Reduction of BMP6‐induced bone formation by calcium phosphate in wild‐type compared with nude mice

Nude mice have been extensively used to investigate the potency of tissue engineering strategies for bone repair. However, the contribution of pro‐inflammatory and proregenerative stimuli of the host for the process of new bone formation and integration remains poorly understood. In this study, ectopic bone formation was investigated in nude (Nu) versus wild‐type (WT) mice. Calcium phosphate (CaP) scaffolds (CopiOs [Zimmer] and Bio‐Oss [Geistlich]) were loaded with different concentrations of rhBMP6 (40, 120, and 240 ng/mm³ rhBMP6) and implanted subcutaneously in Nu (BALB/c and NMR1) and WT (BALB/c and c57BL/6) mice. CaP scaffolds loaded with rhBMP6 did not form bone in WT mice. However, in Nu mice, 40 ng/mm³ rhBMP6 was sufficient to generate relevant volumes of new bone at 6 weeks after implantation. Looking into potential underlying mechanisms, TNF‐α blocking antibodies were injected intraperitoneally but could not restore bone formation. Also, mouse periosteal cells (mPDCs) seeded in CopiOs loaded with rhBMP6 did not significantly improve the outcome. Abrogation of bone formation was associated with dense cellular infiltration, in particular with the presence of CD3+ T‐lymphocytes. To probe a correlation between calcium ions and impaired bone formation in WT mice, type 1 collagen gels were loaded with rhBMP6 and calcium chloride and injected subcutaneously. These gels generated new bone in WT mice despite the increased percentage of CD3+ cells at Day 3 after implantation as compared with control gels. Overall, this study illustrated the negative effect of the inflammatory host response on the bone‐forming capacity of rhBMP6 coated on bioceramic scaffolds.     

Rapid treatment of full‐thickness skin loss using ovine tendon collagen type I scaffold with skin cells

The full‐thickness skin wound is a common skin complication affecting millions of people worldwide. Delayed treatment of this condition causes the loss of skin function and integrity that could lead to the development of chronic wounds or even death. This study was aimed to develop a rapid wound treatment modality using ovine tendon collagen type I (OTC‐I) bio‐scaffold with or without noncultured skin cells. Genipin (GNP) and carbodiimide (EDC) were used to cross‐link OTC‐I scaffold to improve the mechanical strength of the bio‐scaffold. The physicochemical, biomechanical, biodegradation, biocompatibility, and immunogenicity properties of OTC‐I scaffolds were investigated. The efficacy of this treatment approach was evaluated in an in vivo skin wound model. The results demonstrated that GNP cross‐linked OTC‐I scaffold (OTC‐I_GNP) had better physicochemical and mechanical properties compared with EDC cross‐linked OTC‐I scaffold (OTC‐I_EDC) and noncross‐link OTC‐I scaffold (OTC‐I_NC). OTC‐I_GNP and OTC‐I_NC demonstrated no toxic effect on cells as it promoted higher cell attachment and proliferation of both primary human epidermal keratinocytes and human dermal fibroblasts compared with OTC‐I_EDC. Both OTC‐I_GNP and OTC‐I_NC exhibited spontaneous formation of bilayer structure in vitro. Immunogenic evaluation of OTC‐I scaffolds, in vitro and in vivo, revealed no sign of immune response. Finally, implantation of OTC‐I_NC and OTC‐I_GNP scaffolds with noncultured skin cells demonstrated enhanced healing with superior skin maturity and microstructure features, resembling native skin in contrast to other treatment (without noncultured skin cells) and control group. The findings of this study, therefore, suggested that both OTC‐I scaffolds with noncultured skin cells could be promising for the rapid treatment of full‐thickness skin wound.     

TGF‐β1‐activated type 2 dendritic cells promote wound healing and induce fibroblasts to express tenascin c following corneal full‐thickness hydrogel transplantation

We showed previously that 1‐ethyl‐3‐(3‐dimethylamino‐propyl)‐carbodiimide hydrochloride (EDC) cross‐linked recombinant human collagen III hydrogels promoted stable regeneration of the human cornea (continued nerve and stromal cell repopulation) for over 4 years. However, as EDC cross linking kinetics were difficult to control, we additionally tested a sterically bulky carbodiimide. Here, we compared the effects of two carbodiimide cross linkers—bulky, aromatic N‐cyclohexyl‐N0‐(2‐morpholinoethyl)‐carbodiimide (CMC), and nonbulky EDC—in a mouse corneal graft model. Murine corneas undergoing full‐thickness implantation with these gels became opaque due to dense retro‐corneal membranes (RCM). Corneal epithelial cytokeratin 12 and alpha smooth muscle actin indicative of functional tissue regeneration and wound contraction were observed in RCM surrounding both hydrogel types. However, quantitatively different levels of infiltrating CD11c⁺ dendritic cells (DC) were found, suggesting a hydrogel‐specific innate immune response. More DC infiltrated the stroma surrounding EDC‐N‐hydroxysuccinimide (NHS) hydrogels concurrently with higher fibrosis‐associated tenascin c expression. The opposite was true for CMC‐NHS gels that had previously been shown to be more tolerising to DC. In vitro studies showed that DC cultured with transforming growth factor β1 (TGF‐β1) induced fibroblasts to secrete more tenascin c than those cultured with lipopolysaccharide and this effect was blocked by TGF‐β1 neutralisation. Furthermore, tenascin c staining was found in 40‐ to 50μm long membrane nanotubes formed in fibroblast/DC cocultures. We suggest that TGF‐β1 alternatively activated (tolerising) DC regulate fibroblast‐mediated tenascin c secretion, possibly via local production of TGF‐β1 in early wound contraction, and that this is indirectly modulated by different hydrogel chemistries.     

Stereotactic Body Radiotherapy Versus Metastasectomy in Patients With Pulmonary Metastases From Soft Tissue Sarcoma

The lung is the preferred site of metastasis from soft tissue sarcoma (STS). This systematic review aims to evaluate the outcomes of stereotactic body radiotherapy (SBRT) and metastasectomy (MTS) for the treatment of lung metastases from STS. A systematic review was carried out according to the PRISMA protocol. PubMed, Medline, EMBASE, Cochrane Library, Ovid and Web of Knowledge databases were searched for English-language articles to December 2018 using a predefined strategy. Retrieved studies were independently screened and rated for relevance. Data were extracted by two researchers. In total, there were 1306 patients with STS: 1104 underwent MTS and 202 had SBRT. The mean age ranged from 40 to 55.8 years in the MTS group and from 47.9 to 64 years in the SBRT group. The cumulative death rate was 72% (95% confidence interval 59–85%) in the MTS group and 56% (38–74%) in the SBRT group. The cumulative mean overall survival time was 46.7 months (36.4–57.0%) in the MTS group and 47.6 months (33.7–61.5%) in the SBRT group. The cumulative rate of patients alive with disease was 5% (2–9%) in the MTS group and 15% (6–36%) in the SBRT group. Finally, the cumulative rate of patients alive without disease in the two groups was 19% (9–29%) and 20% (10–50%), respectively. Our study showed that local treatment of pulmonary metastases from STS with SBRT, compared with surgery, was associated with a lower cumulative overall death rate and similar overall survival time and survival rates without disease. By contrast, SBRT was associated with a higher survival rate with disease than MTS. Large randomised trials are necessary to confirm these findings and to establish whether SBRT may be a reliable option for early stage disease.     

Imaging update on soft tissue sarcoma

Soft tissue sarcomas (STS) are rare tumours presenting as soft tissue lumps. Ultrasound is often the primary modality for the initial assessment, with MRI the mainstay for lesion characterisation. PET/CT along with other emerging MRI sequences are used in certain situations as an adjunct and problem solving tool in STS staging and assessment of disease recurrence. Recent advances include the promise of whole body MRI, hybrid PET/MRI, diffusion weighted imaging, dynamic contrast enhanced MRI and advances in artificial intelligence. This article discusses current concepts in extremity STS imaging and highlights recent advances.     

超声功能成像在脂肪性肝病研究中的应用进展

脂肪性肝病(Fatty Liver Disease)是我国目前最常见的肝脏病变,主要与过多脂肪蓄积在肝细胞内有关。患者早期常无明显临床表现,晚期有进展为肝硬化的风险。因此,应着眼于早期诊断和预后的判断。超声检查具有无创、便捷、实时、廉价及无辐射等特点,在临床工作中应用广泛。随着超声检查新技术的不断发展,以超声检查新技术为基础的功能成像在脂肪性肝病诊断方面显示出较大的优势,本文主要针对超声功能成像在脂肪性肝病中的应用予以总结分析。