[The ninth edition of TNM staging for lung cancer: precise staging for precise diagnosis and treatment]

The ninth edition of TNM staging for lung cancer has been announced at the 2023 World Lung Cancer Congress and implemented from January 1, 2024. Te focus of the ninth TNM staging change is dividing N2 into N2a and N2b, as well as M1c into M1c1 and M1c2. Although the T staging has not changed, it has played an important role in verifying the eighth edition of the T staging. The subdivision of stage N2 has led some patients with ⅢA of the eighth edition to experience ascending or descending stages, which will more accurately help to assess the condition and prognosis of patients with mediastinal lymph node metastasis, as well as the design of related clinical studies. Modifying the M1c staging will help define oligometastasis and explore new treatment models in the future. The ninth edition of the TNM staging system provides a more detailed division of different tumor loads, but there is no clear explanation for the staging of lung cancer after neoadjuvant therapy. Further data analysis is needed, and it is expected to be answered in the tenth edition of TNM staging.

[Preliminary results of Chinese magnetic sphincter augmentation in treating gastroesophageal reflux disease]

Objective: To examine the preliminary clinical efficacy of Chinese magnetic sphincter augmentation (MSA) in the treatment of gastroesophageal reflux disease (GERD). Methods: According to the enrollment criteria for the MSA developed by ShengJieKang Co. and Shanghai Chest Hospital (SS-MSA) clinical trial, a total of 19 GERD patients were treated with SS-MSA from August 2018 to January 2020 at Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University. The majority of registered cases were male patients with age of (32.2±7.3) years (range: 22 to 50 years), height of (170.7±6.2) cm (range: 160 to 179 cm) and weight of (65.2±10.3) kg (range: 47.5 to 90.0 kg). SS-MSA was implanted via laparoscopy. The major evaluation indexs of postoperative efficacy were the total time of acid exposure within 24 hours and the total number of reflux. Secondary efficacy indicators included: (1) evaluation of the average daily dose of proton pump inhibitor medications; (2) the score of GERD health related quality of life questionnaire (GERD-Q) before and after MSA implantation. Paired design t-test was used to evaluate the efficacy of the SS-MSA. Results: A total of 19 patients underwent SS-MSA surgery successfully. The history of the GERD were 19 (54) months (M(Q(R))). The operation time was 63 (22) minutes and the in-hospital stay was 3 (2) days. No obvious surgical complications occurred. Postoperative adverse events included 14 cases with mild to moderate dysphagia exited after surgery, gradually eased within 1 to 3 months, 1 case with the removal of the device after 1 month of severe swallowing difficulties, 1 case of diarrhea. No corrosion, perforation, displacement occurred. The GERD-Q score (11.0(4.5) vs. 6(1.0), t=4.274, P=0.013), 24-hour acid exposure time (6.2(4.8)% vs. 0.1(0.9)%, t=5.814, P=0.004), and Demeester score (23.72(16.20) vs. 0.96(3.10), t=6.678, P=0.003) were significantly decreased 1 year after surgery(n=5). Proton pump inhibitor reuse rates were 6/18, 5/15, 3/10, and 1/5 in 1, 3, 6 and 12 months after the operation, respectively. Conclusions: SS-MSA implantation is feasible and safe with short hospital stay and rare perioperative complications. The preliminary results is good after 1 year follow-up. It could be expected to be an ideal substitutive for future GERD treatment.

[Experiences of esophageal replacement with ileocolon graft: a series of 34 cases]

Objective: To evaluate the safety and effectiveness of esophageal replacement with ileocolon graft. Methods: Totally 34 cases of esophageal replacement with ileocolon graft from July 2015 to November 2017 at Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiaotong University were analyzed retrospectively, including 24 male and 10 female, aging from 7 to 72 years old. Esophageal replacement with ileocolon graft by right and/or middle colic artery as a blood supply using retrosternal route except one subcutaneous route. The primary esophageal disease, postoperative complication rate and quality of life were analyzed. Results: The overall postoperative complication rate was 23.5% (8/34), cervical anastomotic leakage rate of 5.9% (2/34), necrosis of colon graft of 5.9% (2/34). There were 3 patients experienced re-operation including 2 patients with colon graft necrosis and 1 patient with intestinal obstruction after ERC. One patient with colon graft necrosis died of septic shock after reoperation. Six cases of cervical esophago-jejunal anastomosis stenosis and 1 case of diarrhea occurred in the later time. All patients were followed up for a median time of 9 months (range: 1 to 28 months), 32 cases survived but 1 patient died until last follow-up by the end of December 2017. Conclusion: Esophageal replacement with ileocolon graft by right and/or middle colic artery as a blood supply using retrosternal route was safe and effective.

Classification of water contamination developed by 2-D Gabor wavelet analysis and support vector machine based on fluorescence spectroscopy

The identification of the specific categories of pollutants in the urban water supply system is necessary. Traditional detection methods are based mainly on common water quality indicators. However, inspecting these water quality indicators is made difficult by issues such as long analysis time, insufficient sensitivity, need for reagents, and generation of waste liquid. These problems hinder high-frequency water detection and monitoring. In this study, three-dimensional (3D) fluorescence spectroscopy is adopted as a monitoring method for water quality. An identification method based on two-dimensional (2D) Gabor wavelets and support vector machine (SVM) multi-classification is also proposed. The Delaunay triangulation method for interpolation is used to pre-process 3D fluorescence spectra and thereby eliminate Rayleigh scattering and Raman scattering. A 2D Gabor wavelet function generated by filters of different scales and rotation angles is proposed to extract the features of the spectra. The block statistics method, based on Gabor feature description, is employed to enhance the efficiency in describing spectra features. Then, multiple SVM classifiers are used in pollutant classification and recognition. By comparing the proposed method with principal component analysis, which is a commonly used feature extraction method, this study finds that the application of 2D Gabor wavelets and block statistics can effectively describe the characteristics of 3D fluorescence spectra. Moreover, 2D Gabor wavelets achieve high classification accuracy, especially for substances with closely positioned or overlapping characteristic peaks.

Experimental study on TGF-β1-mediated CD147 expression in oral submucous fibrosis

OBJECTIVE

Although previous evidence indicates that CD147 is closely involved in the progression of organ fibrosis and various signaling pathways have been proven to regulate its expression, the role of CD147 in oral submucous fibrosis (OSF) remains largely unknown.

METHODS

In this study, we investigated the expression of CD147 and transforming growth factor β1 (TGF-β1) in human samples of an OSF tissue array by immunohistopathology. Pearson's correlation analysis was conducted to explore the correlation between CD147 and TGF-β1. Immunofluorescence and Western blotting were used to investigate to levels of CD147 in Human Oral Keratinocytes (HOKs) followed by TGF-β1 or LY2157299, an inhibitor of TGF-β1 receptor and arecoline stimulation.

RESULTS

We found that CD147 was highly expressed in both HOKs and the fibrotic oral mucosa and that this expression was correlated with TGF-β1 expression. Additionally, CD147 levels were significantly associated with the fibrosis stage. The TGF-β1 signaling pathway was found to be mainly responsible for CD147 up-regulation after arecoline treatment whereas inhibition of TGF-β1 down-regulated CD147 expression.

CONCLUSION

Our findings suggest arecoline promotes CD147 expression via the TGF-β1 signaling pathway in HOKs, whereas overexpression of CD147 may promote OSF progression.

Comparative study of functional and aesthetically outcomes of reverse digital artery and reverse dorsal homodigital island flaps for fingertip repair

This retrospective study was designed to compare functional and cosmetic outcomes of the reverse digital artery island flap and reverse dorsal homodigital island flap in fingertip repair. A total of 23 patients were followed for 24 to 30 months. The reverse digital artery island flap was used in 12 patients, and reverse dorsal homodigital island flap in another 11 patients. Flap sensibility was assessed using the Semmes-Weinstein monofilament test and static 2-point discrimination test. Patient satisfaction, active motion of the finger joints, complications and cold intolerance were evaluated. The static 2-point discrimination and Michigan Hand Outcomes Questionnaire (appearance) of the fingers treated with a reverse digital artery flap were significantly better than those with a reverse dorsal homodigital flap. The static 2-point discrimination of the skin-grafted donor sides after dorsal homodigital flap were poorer than that in the contralateral finger. No significant differences were found between the two flaps for pressure or touch sensibility, active ranges of digital motion, complications and cold intolerance.

LEVEL OF EVIDENCE

III.

Anti-CII antibody as a novel indicator to assess disease activity in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that affects a variety of organ systems. Anti-dsDNA Abs and complement factors have been used as indicators of lupus activity for more than 50 years. A novel indicator of activation in SLE is reported in this paper. Anti-collagen type II (CII) Ab was obviously elevated in patients with SLE compared to those patients with ankylosing spondylitis (AS) and healthy controls (HCs). Anti-CII-Ab-positive patients with SLE showed significantly higher levels of serum IgG and higher titers of ANA but lower levels of C3 and C4 than controls. A positive correlation was demonstrated between anti-CII Ab and serum IgG in SLE patients (r = 0.50, p < 0.0001). The negative correlations of anti-CII Ab with C3 and C4 were observed in SLE patients (r = -0.36, p = 0.0013; r = -0.37, p = 0.0006, respectively). The reduced anti-CII Ab level was accompanied by decreased level of serum IgG and increased levels of C3 and C4 after regular treatment. Therefore, anti-CII Ab could be a novel indicator for monitoring activity of SLE.

Dental Abnormalities Caused by Novel Compound Heterozygous CTSK Mutations

Cathepsin K (CTSK) is an important protease responsible for degrading type I collagen, osteopontin, and other bone matrix proteins. The mutations in the CTSK gene can cause pycnodysostosis (OMIM 265800), a rare autosomal recessive bone dysplasia. Patients with pycnodysostosis have been reported to present specific dental abnormalities; however, whether these dental abnormalities are related to dysfunctional CTSK has never been reported. Here we investigated the histologic changes of cementum and alveolar bone in a pycnodysostosis patient, caused by novel compound heterozygous mutations in the CTSK gene (c.87 G>A p.W29X and c.848 A>G p.Y283C). The most impressive manifestations in tooth were extensive periradicular high-density clumps with unclear periodontal space by orthopantomography examination and micro-computed tomography scanning analysis. Hematoxylin/eosin and toluidine blue staining and atomic force microscopy analysis showed that the cementum became significantly thickened, softened, and full of cementocytes. The disorganized bone structure was the main character of alveolar bone. The p.W29X mutation may represent the loss-of-function allele with an earlier termination codon in the precursor CTSK polypeptide. Residue Y283 is highly conserved among papain-like cysteine proteases. Three-dimensional structure modeling analysis found that the loss of the hydroxybenzene residue in the Y283C mutation would interrupt the hydrogen network and possibly affect the self-cleavage of the CTSK enzyme. Furthermore, p.Y283C mutation did not affect the mRNA and protein levels of overexpressed CTSK in COS-7 system but did reduce CTSK enzyme activity. In conclusion, the histologic and ultrastructural changes of cementum and alveolar bone might be affected by CTSK mutation via reduction of its enzyme activity (clinical trial registration: ChiCTR-TNC-10000876).

Changes and clinical significance of peripheral blood helper T lymphocyte and natural killer (NK) cells in unexplained recurrent spontaneous abortion (URSA) patients after abortion and successful pregnancy

OBJECTIVE

This study aims to investigate the number changes and the clinical significance of the peripheral blood T lymphocyte subsets and NK (natural killer) cells in unexplained recurrent spontaneous abortion (URSA) patients before and after abortion, as well as after successful pregnancy.

MATERIALS AND METHODS

Thirty-nine URSA patients (URSA-abortion group), among who 22 patients were followed up until the final successful parturition (URSA-pregnancy group), 31 normal-pregnancy (NP) cases and 25 normal non-pregnancy (NNP) control cases in which the peripheral blood T lymphocytes and subsets, B cells, and NK cells were assessed flow cytometry.

RESULTS

Compared with the URSA-pregnancy group and the NP group, the Th cells and NK cells of the URSA-abortion group increased (p < 0.05); compared with the NNP group, the total number of T cells decreased after the first, second, and third month of the URSA abortion (p < 0.05); Th cells decreased within one to six months of the URSA abortion (p < 0.05); proportion of NK cells was significantly higher in URSA patients (p < 0.05).

CONCLUSION

The abnormal numbers of the peripheral blood T cell subsets and NK cells were related with the occurrence of URSA.

[Research progress of cell sheet technology and its applications in tissue engineering and regenerative medicine]

Cell sheet engineering is an important technology to harvest the cultured cells in the form of confluent monolayers using a continuous culture method and a physical approach. Avoiding the use of enzymes, expended cells can be harvested together with endogenous extracellular matrix, cell-matrix contacts, and cell-cell contacts. With high efficiency of cell loading ability and without using exogenous scaffolds, cell sheet engineering has several advantages over traditional tissue engineering methods. In this article, we give an overview on cell sheet technology about its applications in the filed of tissue regeneration, including the construction of soft tissues (corneal, mucous membrane, myocardium, blood vessel, pancreas islet, liver, bladder and skin) and hard tissues (bone, cartilage and tooth root). This techonoly is promising to provide a novel strategy for the development of tissue engineering and regenerative medicine. And further works should be carried out on the operability of this technology and its feasibility to construct thick tissues.

Locally injection of cell sheet fragments enhances new bone formation in mandibular distraction osteogenesis: a rabbit model

Effective methods to shorten the treatment period of distraction osteogenesis (DO) are needed. To investigate whether injections of osteogenic bone marrow stromal cell (BMSC) sheet fragments could be used to facilitate new bone formation during DO, 30 rabbits underwent bilateral mandibular osteotomy and their mandibles were lengthened at a rate of 0.75 mm/12 h for 6 days after a 5-day latency period. There were three treatment groups (n = 10 for each group): Serum-free medium, dissociated BMSCs, and BMSC sheet fragments. A local injection was conducted with a needle directly into the distracted areas immediately after distraction. Rabbits were sacrificed for examination at 3 and 6 weeks after injection. Gross examination, radiographic evaluation, and micro-CT scanning indicated a significant increase in bony union in the BMSC sheet fragment group, compared with the medium group and the dissociated cell group. The histomorphometric analysis showed more intensive bone formation in the sheet fragment group than the other two groups at each time point. Additionally, the peak load was significantly higher in the fragment group than those in the others. The results show that injection of BMSC sheet fragments promotes bone formation in DO and indicate a promising approach to shorten the treatment period of osteodistraction.

[Cell-based approaches to promote bone regeneration in distraction osteogenesis]

OBJECTIVE

To summarize the recent progress of cell-based approaches for promoting bone regeneration in distraction osteogenesis (DO).

METHODS

Recent literature concerning enhancement of bone regeneration following DO using cell-based approaches was reviewed and analyzed.

RESULTS

An overview of 4 different cell-based approaches was mainly provided: single cell injection, cell scaffold-based strategies/injectable tissue engineered bone, microtissue technology or cell aggregate technology, and stem cell gene therapy. Each has its advantages and disadvantages. Other methods are still in the experimental research except that compound injection of bone marrow mesechymal stem cells and platelet-rich plasma has been applied to clinical practice.

CONCLUSION

The cell-based approach is a promising strategy in the field of bone regenerative medicine. These approaches have bright future in promoting bone regeneration and reducing the treatment period in DO in the clinical application. However, well-designed preclinical studies are required to establish safe and effective guidelines for cell-based approaches to promoting bone regeneration during DO.

Report of two Chinese patients suffering from CLCN7-related osteopetrosis and root dysplasia

Osteopetrosis is a group of genetic bone disorders. There are three types of osteopetrosis: autosomal recessive osteopetrosis (ARO), autosomal dominant osteopetrosis type II (ADO II), and intermediate autosomal recessive osteopetrosis (IARO). The prevalence of ADO II is about 1:100,000, while no more than 20 cases of IARO have been reported worldwide. We present the first Chinese IARO patient with a novel homozygous variant in CLCN7 gene (p. Pro470Leu) and an ADO II patient with a heterozygous variant in CLCN7 gene (p. Arg286Trp). In addition to general osteosclerosis, the striking features of these two patients are unerupted teeth with root dysplasia. We speculate that ClC-7 in different tooth cells may contribute directly to the root development, the defect of ClC-7 may have a dose dependent effect on the phenotype of root dysplasia, and the tooth position may also affect the root phenotype with dysfunctional ClC-7.

Clinical and animal research findings in pycnodysostosis and gene mutations of cathepsin K from 1996 to 2011

Cathepsin K (CTSK) is a member of the papain-like cysteine protease family. Mutations in the CTSK gene cause a rare autosomal recessive bone disorder called pycnodysostosis (OMIM 265800). In order to follow the advances in the research about CTSK and pycnodysostosis, we performed a literature retrospective study of 159 pycnodysostosis patients reported since 1996 and focused on the genetic characteristics of CTSK mutations and/or the clinical phenotypes of pycnodysostosis. Thirty three different CTSK mutations have been found in 59 unrelated pycnodysostosis families. Of the 59 families, 37.29% are from Europe and 30.51% are from Asia. A total of 69.70% of the mutations were identified in the mature domain of CTSK, 24.24% in the proregion, and 6.06% in the preregion. The hot mutation spots are found in exons 6 and 7. CTSK mutations result in total loss or inactivity of the CTSK protein, which causes abnormal degradation of bone matrix proteins such as type I collagen. Skeletal abnormalities, including short stature, an increase in bone density with pathologic fractures, and open fontanels and sutures, are the typical phenotypes of pycnodysostosis. Research on Ctsk(-/-) mouse models was also reviewed here to elucidate the biological function of Ctsk and the mechanism of pycnodysostosis. New evidence suggests that Ctsk plays an important role in the immune system and may serve as a valid therapeutic target in the future treatment of pycnodysostosis.

Enhancing bone formation by transplantation of a scaffold-free tissue-engineered periosteum in a rabbit model

OBJECTIVES

The periosteum plays an important role in bone regeneration. However, the harvesting of autogenous periosteum is associated with disadvantages such as donor site morbidity and limited donor sources. This study uses an osteogenic predifferentiated cell sheet to fabricate a scaffold-free tissue-engineered periosteum (TEP).

MATERIAL AND METHODS

We generated an osteogenic predifferentiated cell sheet from rabbit bone marrow stromal cells (BMSCs) using a continuous culture system and harvested it using a scraping technique. Then, the in vitro characterization of the sheet was investigated using microscopy investigation, quantitative analysis of alkaline phosphatase (ALP) activity, and RT-PCR. Next, we demonstrated the in vivo osteogenic potential of the engineered sheet in ectopic sites together with a porous β-tricalcium phosphate ceramic. Finally, we evaluated its efficiency in treating delayed fracture healing after wrapping the cell sheet around the mandible in a rabbit model.

RESULTS

The engineered periosteum showed sporadic mineralized nodules, elevated ALP activity, and up-regulated gene expression of osteogenic markers. After implantation in the subcutaneous pockets of the donor rabbits, the in vivo bone-forming capability of the engineered periosteum was confirmed by histological examinations. Additionally, when wrapping the engineered periosteum around a mandibular fracture gap, we observed improved bone healing and reduced amounts of fibrous tissue at the fracture site.

CONCLUSION

The osteogenic predifferentiated BMSC sheet can act as a scaffold-free TEP to facilitate bone regeneration. Hence, our study provides a promising strategy for enhancing bone regeneration in clinical settings.

Engineering injectable bone using bone marrow stromal cell aggregates

With the increasing popularity of minimally invasive surgery, to develop an injectable bone would be highly preferable for the repair of bone nonunions and defects. However, the use of dissociated cells and exogenous carriers to construct injectable bone faces several drawbacks. To circumvent these limitations, we first harvested a cell sheet from rabbit bone marrow stromal cells using a continuous culture method and a scraping technique. The obtained sheet was then cut into fragments of multicellular aggregates, each of which was composed of a certain number of cells, extracellular matrix, and intercellular connections. The aggregates showed apparent mineralization properties, high alkaline phosphatase activity, increased osteocalcin content, and upregulated bone markers, implying their in vitro osteogenic potential. Then, serum-free medium (the control group), dissociated cell suspension (the cell group), and suspension of multicellular aggregates (the aggregate group) were injected subcutaneously on the back of the nude mice to evaluate ectopic bone formation. The results revealed that the aggregate group showed significantly larger and denser bone at the injection sites than the cell group, whereas bone formation did not occur in the control group. Additionally, when injecting them locally into the mandibular fracture gap of delayed healing in a rabbit model, we observed the most improved bone healing in the aggregate group. More cells survive and retain at the injection sites in the aggregate group than that in the cell group postoperatively. Our study indicates that the multicellular aggregates might be considered a promising strategy to generate injectable bone tissue and improve the efficacy of cell therapy.

Engineering scaffold-free bone tissue using bone marrow stromal cell sheets

The use of exogenous scaffolds to engineer bone tissue faces several drawbacks including insufficient biological activity, potential immunogenicity, elevated inflammatory reaction, fluctuating degradation rate, and low cell-attachment efficiency. To circumvent these limitations, we sought to engineer large scaffold-free bone tissue using cell sheets. We harvested intact cell sheets from bone marrow stromal cells using a continuous culture method and a scraping technique. The cell sheets were then rolled and fabricated into large constructs. Finally, the constructs were implanted into the subcutaneous pockets of nude mice. The cells within the sheet maintained in vitro osteogenic potential after osteoblast differentiation. Computed tomography scans and histological examination confirmed new bone formation in vivo. Additionally, the engineered bone exhibited enhanced compressive strength. Our results indicate that the BMSC sheets can facilitate the formation of functional three-dimensional bone tissue without the use of exogenous scaffolds. Hence, the study provides an intriguing alternative strategy for bone repair.

Vitalized guided bone regeneration membrane from marrow stromal cells

PURPOSE

Various materials have been used to make guided bone regeneration membranes. The purpose of this study was to create a novel osteogenic membrane without synthetic material. The osteogenic potential of the membrane was evaluated by both in vitro and in vivo testing.

MATERIALS AND METHODS

The membrane was obtained by continuous culture of marrow stromal cells. The structure of the membrane was characterized by staining with hematoxylin-eosin, von Kossa, and carboxyfluorescein diacetate; immunohistochemical staining against collagen type I; electron microscopy; and energy-dispersive spectrometry. The osteogenic potential and bone augmentation effect of the membrane were investigated by implantation of the membrane and a membrane/natural coral composite into nude mice, respectively.

RESULTS

The membrane was composed of living cells and a dense matrix of collagen type I. Mineral deposition was apparent through electronic microscopic observation and von Kossa staining. Energy-dispersive spectrometry indicated that the calcium:phosphorus ratio of mineral was 1.71 in the membrane. The membrane had formed a thin layer of bone 2 months after implantation subcutaneously. In the bone augmentation specimens, new bone was observed histologically on the surface and in the pores of natural coral in all specimens of membrane-coral composite.

CONCLUSIONS

This study developed a novel strategy to produce a vital guided bone regeneration membrane without synthetic material. Membrane derived from marrow stromal cells was osteogenic and had an optimizing bone augmentation effect.

Effect of sonication on UV disinfectability of primary effluents

In this paper, the effect of sonication on the UV disinfection kinetics of primary effluents was investigated. Wastewater samples were collected from local municipal treatment plants and were sonicated with a 20-kHz ultrasound reactor at constant power but varying sonication times. Sonicated samples were irradiated using low-pressure UV light to obtain the UV dose-response curves (DRC). Results showed that sonication improved the UV disinfection of primary effluents by (1) increasing the initial slope of DRC (i.e., k1) and (2) decreasing the tailing level of the UV dose-response curve (i.e., beta). This improvement was confirmed to be caused by the breakage of large particles (> 60 microm) that are known to protect coliforms from UV photons. It also was found that the log reduction of the tailing level of DRC was directly proportional to the log reduction of the number of large particles (> 60 microm) present in the effluent sample. Although the number of large particles was proportional to the coliform count at high UV dosage, the proportionality constant varied from 0.05 to 0.25, depending on the sample.

Novel approach to engineer implantable nasal alar cartilage employing marrow precursor cell sheet and biodegradable scaffold

PURPOSE

Repair of nasal and auricular malformation remains an obstacle for clinicians because of poor regenerative capacity of cartilage and limitation of donor sites. In the current study, we developed a novel approach to regenerate implantable nasal alar cartilage by using marrow precursor cell (MPC) sheet and biodegradable scaffold of polylactic acid-polyglycolic acid copolymer (PLGA).

MATERIALS AND METHODS

Rabbit MPCs were expanded and induced by transforming growth factor-beta to improve chondrocyte phenotype. MPC sheets were obtained by continuous culture and used to wrap PLGA scaffold in the shape of the human nasal alar. The constructs were incubated in a spinner flask for 4 weeks, and cartilage formation was investigated by gross inspection and histological examination. The constructs were then implanted subcutaneously into a nude mouse. Specimens were harvested and analyzed 4 weeks after implantation.

RESULTS

The results showed that cartilaginous tissue formed and PLGA absorbed during in vitro incubation. Histological analysis showed engineered cartilage consisted of evenly spaced lacunae embedded in a matrix rich in proteoglycans, and kept the initial shape of the nasal alar. Based on this "MPC sheet combining polymer strategy," implantable nasal alar could be successfully regenerated.

CONCLUSION

This strategy has the advantage of high cell transplantation efficiency and great potential for clinical application.

Repair of critical bone defects with injectable platelet rich plasma/bone marrow-derived stromal cells composite: experimental study in rabbits

BACKGROUND

Platelet-rich plasma (PRP) has been applied to promote bone healing and developed as a novel material for bone regeneration. This study aimed to investigate the feasibility of PRP carrier to deliver bone marrow derived stromal cells (BMSCs) and regenerate bone tissues to reconstruct critical bone defects in rabbits.

METHODS

Critical sized defect were made on eighteen rabbits' crania and treated by different composites: BMSCs/PRP (n=6); Autogenous particulate cancellous bone group (n=6) and PRP alone group (n=6). The defects were evaluated by gross observation, radiographic examination, histological examination, and mechanical examination at 12 weeks postoperatively.

RESULTS

The results showed that repair of bone defect was the least in PRP alone group, and significant new bone formation could be observed in BMSCs/PRP group and particulate cancellous bone group, radiopacity area in BMSCs/PRP group attained 76.5%, which was in the same range of that in autogenous particulate cancellous bone group (82.4% in radiopacity area), compressive strength of engineered bone in BMSCs/PRP group attained 71% of that in autogenous particulate cancellous bone group (p<0.05).

CONCLUSION

These data implicated that BMSCs delivered from PRP gel can repair bony defect in immunocompetent animals, and the tissue engineered bone in BMSCs/PRP group is comparable to autogenous particulate cancellous bone group for the repair of critical-sized bone defect.

Autologous Injectable Tissue-Engineered Cartilage by Using Platelet-Rich Plasma: Experimental Study in a Rabbit Model

PURPOSE

Platelet-rich plasma (PRP) has been widely applied to promote tissue healing and used as a novel injectable scaffold in bone tissue engineering. However, there is no report about its feasibility to support chondrogenesis. This study aimed to investigate the feasibility of a PRP carrier to deliver chondrocytes and regenerate cartilage tissues in a rabbit model via injection.

MATERIALS AND METHODS

Eight New Zealand rabbits were divided into a chondrocytes/PRP group (n = 4) and a PRP-alone group (n = 4). Chondrocytes harvested from the auricular root of New Zealand rabbits were cultured and harvested. The chondrocytes were then mixed with PRP solution to generate chondrocytes/PRP composites with final cellular density of 5.0 x 10(7)/mL. Bovine thrombin was used as a cross-linking agent to gel chondrocytes/PRP composites, then, the composites were injected subcutaneously into the dorsal tissue of cell donor animals. As controls, PRP alone was injected into another 4 rabbits. At the second month after injection, rabbits were prepared for magnetic resonance imaging. The samples were then harvested for macroscopical examination, histological analysis, and glycosaminoglycan quantification.

RESULTS

Two months after injection, the hard knobbles were easily palpated under the dorsal skin of the animals in the chondrocytes/PRP group, and magnetic resonance images showed the presence of cartilage-like tissues. In histological analysis, formation of new cartilage was observed in the chondrocytes/PRP composites. Safranin-O staining and Masson's trichrome staining showed proteoglycan and collagen were produced in matrices. In contrast, no tissue formed in the PRP-alone group.

CONCLUSIONS

This study suggests the feasibility of using PRP as injectable scaffold seeded with chondrocytes to regenerate cartilage and showed the potential of using this method for the reconstruction of cartilage defects.

Segmental bone tissue engineering by seeding osteoblast precursor cells into titanium mesh-coral composite scaffolds

The size and specific shape of bone grafts are important for jaw reconstruction. In this experiment, segmental bone grafts were engineered in a predetermined shape via seeding osteoblast precursor cells into titanium mesh-coral composite scaffolds. Titanium meshes were moulded into the shape of a column with length 12 mm and diameter 8mm. The column was filled with natural coral granules and the complex acted as a cell-seeding scaffold. About 4 x 10(7) osteoblast precursor cells in 200 microl cell-culture medium were seeded into each of six scaffolds and incubated in vitro for 2 days. Then, the composites were implanted subcutaneously into the backs of nude mice and incubated in vivo. Two months after implantation, the animals were killed and new bone formed in the scaffolds was investigated by gross inspection, X-ray examination, histological observation and mechanical testing. The results showed that newly formed tissue was red and presented the gross appearance of bone, and kept the original shape of the column. Titanium mesh was situated on the surface of the bone graft. An X-ray blocking shadow was observed in and around the titanium scaffolds; most of the coral granules had been absorbed. Histological observation demonstrated a large amount of new bone formed and integrated well with titanium mesh. Mechanical testing showed that new bone improved the mechanical property of the graft significantly. In conclusion, a titanium mesh-coral composite scaffold with osteoblast precursor cells is an efficient means to engineer segmental bone, possessing the desired shape and mechanical strength.

[Fabrication of collagen/sodium hyaluronate scaffold and its biological characteristics for cartilage tissue engineering]

OBJECTIVE

To develop a scaffold material containing collagen 1 and sodium hyaluronate for the cartilage tissue engineering and to evaluate its biocompatibility by using the rabbit chondrocytes derived from a mandibular condylar process.

METHODS

The porous matrices containing collagen 1 and sodium hyaluronate were fabricated by the freeze-drying technique and were crosslinked by using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). The microstructure of the scaffold was observed under the scanning electron microscope (SEM), and the enzymatic degradation test was performed to compare the ability of the scaffold resistance to collagenase before and after the crosslinking. The chondrocytes from the rabbits' condylar process were isolated and cultured before they were seeded into the scaffold, and cell attachment and proliferation were measured by the cell count 1, 3, 5, 7 and 10 days after the cell being seeded; then, the biocompatibility of the scaffold was evaluated by the light microscopic examination, histological examination, and the SEM exmination.

RESULTS

The porous structure of the scaffold facilitated the penetration and attachment of the seeded cells. The porosity was 83.7% and the pore size was 100-120 microm. The cell number increased from 3.7 x 10(4) per scaffold 1 day after the cell being seeded to 8.2 x 10(4) per scaffold 10 days after the cell being seeded. The crosslinking treatment could significantly enhance the scaffold resistance to the collagenase activity. The examinations under the light microscope and SEM indicated that the chondrocyte adhered and spread well on the scaffold, and the extracellular matrices were also observed around the chondrocytes.

CONCLUSION

The porous scaffold composed of collagen I and hyaluronan has an appropriate structure and a good biocompatibility for the attachment and proliferation of the chondrocytes, which can facilitate it to become a useful scaffold in the cartilage tissue engineering.

Engineering cartilage tissues with the shape of human nasal alar by using chondrocyte macroaggregate--Experiment study in rabbit model

Despite of progresses in tissue engineering based on cell/scaffold strategy, uneven cell distribution as well as tissue formation in the scaffold, limited cell seeding efficiency and inflammatory reaction triggered by the degradation of scaffold remain problems to be resolved. In this study, we proposed a novel cell-macroaggregate cultivation system, and explored a feasible strategy to construct three-dimensional cartilage tissue with shape of human nasal alar by using cell macroaggregate. Isolated chondrocytes was cultured at high density to form a monolayer chondrocyte sheet as well as expanded for seeding on the sheet to produce mechanically operable cell macroaggregate. Chondrocyte macroaggregates were then fabricated into transplants with shape of nasal alar by using Internal support or External scaffold techniques; results of in vivo chondrogenesis were investigated in immunocompetent animal. Chondrocyte macroaggregates presented long survival time and good viability; constructs fabricated using both techniques can develop into tissues with characteristic structure of native cartilage, glycosaminoglycans as well as type II collagen were highly produced in the ECM of engineered cartilages. By placing hyaluronan ester film as Internal support, the predetermined shape of the chondrocyte macroaggregate can be well maintained. In contrast, due to the poor mechanical stability of grafts fabricated in External scaffold group, obvious deformation occurred in harvested specimens. The experiment proved the usefulness of chondrocyte macroaggregate in cartilage regeneration, and provided a new strategy to engineer cartilage with special shape by using cell macroaggregate/biodegradable support.

Comparative study between coral-mesenchymal stem cells-rhBMP-2 composite and auto-bone-graft in rabbit critical-sized cranial defect model

Tissue engineered bone has become a bone substitute for the treatment of bone defects in animal research. This study investigated the osteogenesis capacity of coral-MSCs-rhBMP-2 composite with the auto-bone-graft as control. Coral-MSCs-rhBMP-2 composite were fabricated by coral (as main scaffold), rhBMP-2 (as growth factor), and MSCs (cultured from iliac marrow as seed cells). Critical-sized defects (d = 15 mm) were made on forty rabbits crania and treated by different composite scaffolds: iliac autograft (n = 8), coral (n = 8), rhBMP-2/coral (n = 8), and MSCs/rhBMP-2/coral (n = 8). The defects were evaluated by gross observation, radiographic examination, histological examination, and histological fluorescence examinations after 8 and 16 weeks. The results showed that repair of bone defect was the least in coral group, and significant ingrowth of new bone formation and incorporation could be seen with 77.45% +/- 0.52% in radiopacity in MSCs/rhBMP-2/coral group, which was similar to that in iliac autograft group (84.61% +/- 0.56% in radiopacity). New bone formation in MSCs/rhBMP-2/coral group was more than that in rhBMP-2/coral group. And osteogenesis rate in MSCs/rhBMP-2/coral group (10.23 +/- 1.45 microm) was much faster than that in rhBMP-2/coral group (5.85 +/- 2.19 microm) according to histological fluorescence examination. Newly formed bone partly came from induced MSCs in composite scaffold according to bromodeoxyuridine immunohistochemical examination. These data implicated that MSCs could produce synergic effect with coral-rhBMP-2, and the tissue engineered bone of coral-MSCs-rhBMP-2 is comparable to auto-bone-graft for the repair of critical-sized bone defect.

Engineering of human tracheal tissue with collagen-enforced poly-lactic-glycolic acid non-woven mesh: a preliminary study in nude mice

The purpose of the current study is to fabricate tissue engineered trachea with poly-lactic-glycolic acid (PLGA) non-woven mesh enforced by collagen type I. PLGA fibres coated with collagen solution were put together and fabricated into the shape of a human trachea, after drying and cross-linking treatment, a non-woven mesh with "C" shape formed. Chondrocytes from sheep nasal septum cartilage were expanded in vitro and seeded into PLGA/collagen non-woven mesh in the density of 5.0 x 10(7)mL(-1). After 5 days of in vitro incubation, six Cell-PLGA/collagen composites were implanted subcutaneously into the back of 6 nude mice to prefabricate a tissue engineering trachea. Eight weeks later, the cartilage formation was observed by gross inspection and histological examination. Cartilage-like tissue in the shape of the initial PLGA/collagen scaffold had been regenerated successfully without obvious inflammatory response. The tissue engineered trachea cartilage consisted of evenly spaced lacunae embedded in matrix stained red with safranin-O staining. The amount of GAGs in tissue engineered trachea cartilage reached 71.42% of normal value in native cartilage. This study demonstrated that collagen-enforced PLGA non-woven mesh facilitated the adhesion and proliferation of chondrocytes, it also owned adequate mechanical strength to serve as an ideal scaffold for trachea tissue engineering without internal support.

Bone marrow-derived osteoblasts seeded into porous beta-tricalcium phosphate to repair segmental defect in canine's mandibula

BACKGROUND

Bone regeneration is often needed for many aesthetic and reconstructive procedures. Tissue engineering provided a promising approach to supplement existing treatment strategies. In this study, we aimed to evaluate the effect of reconstructing mandibular defect by using bioceramics seeded with bone marrow derived osteoblasts.

METHODS

Canine's autologous marrow stromal cells were Culture-expanded and induced to osteoblastic phenotype, then were seeded into prepared porous beta-tricalcium phosphate, after being incubated in vitro. The cell/ scaffold complexes were implanted into the prepared defect in canines' mandibula and fixed by internal rigid fixation. In control groups, beta-tricalcium phosphate alone and autologous iliums were implanted into the prepared defects. Twelve weeks after implantation, the specimens were examined macroscopically and histologically.

RESULTS

In experimental group and autologous iliums group, new bone grafts were successfully developed at 12 weeks after implantation and repaired the continuity of the mandibula. Histologically, newly formed bone could be observed on the surface and in the pores of beta-tricalcium phosphate in the cell/scaffold group, whereas incomplete bone repair was found in pure beta-tricalcium phosphate group.

CONCLUSION

The harvested bone marrow derived osteoblasts possess the ability to form new bone tissue when seeded onto porous beta-tricalcium phosphate, which shows the potential of using this method to repair large segmental mandibular defect clinically.

[The preparation of a new hydroxyapatite and the study on its cytocompatibility]

The cuttlebones, harvested from cuttles, undergo the chemical reaction in high temperature and high pressure for a certain time. The products are qualitatively analysed, and spacial structure observation and cytocompatibility are tested. The results show that the chemical component of the cuttlebone is CaCO3 and the crystal type is aragonite. Cuttlebones undergo a hydro-thermal reaction, and thus transform into hydroxyapatite-that is, the cuttlebone-transformed hydroxyapatite(CBHA). The CBHA materials have the interconnected microporous network structures. Under the high magnification, CBHAs appear to have many micro-spheres, thus construct a new self-assembled nano-material system. The marrow stromal osteoblasts can adhere to and proliferate well on the surface of the CBHAs. These results show that CBHAs have good biocompatibility. Therefore, it can be a potential candidate scaffold for bone tissue engineering.

Performance of high-rate sludge digesters fed with sonicated sludge

A major limitation of anaerobic sludge digestion is the long hydraulic retention time (HRT) required for satisfactory stabilization which results in large digester size. This study explored a possibility of operating digesters at shortened HRTs by sonication pretreatment of secondary sludges. Four identical digesters designated D1, D2, D3 and D4 were fed with untreated and sludge sonicated at densities of 0.18 W/ml, 0.33 W/ml and 0.52 W/ml, respectively. All digesters were operated at three HRTs of 8-day, 4-day and 2-day. Comparing with the control digester (D1), total solids removal efficiencies improved by 12-19%, 17-36% and 20-39% in digesters D2, D3 and D4, respectively. The volatile solids removal was also increased by 11-21%, 17-33% and 19-36% in the respective digesters. The improved solids degradation corresponded with increase in biogas production by 1.4-2.5, 1.9-3.0 and 1.6-3.1 times, respectively. Increase in methane composition by 2-17% was also noted in all digesters fed with sonicated sludge. An analysis indicated that sonication pretreatment could enhance degradation of carbon, nitrogen and sulfur substances in the digestion. The study suggested that sonication of sludge is a possible pretreatment to shorten the digester operating HRT with improvement in solids degradation, biogas production and methane content. It can be deduced that to maintain a consistent solids loading at a desire performance, sludge digester with smaller size can be designed.

[Experimental study on repair of critical-sized cranial defect by tissue engineered bone]

OBJECTIVE

To evaluate repair of critical-sized cranial defect with tissue engineered bone fabricated by coral, bone mesenchymal stem cells (MSCs) and sustainedly released recombinant human bone morphogenetic protein 2 (rhBMP-2) by collagen.

METHODS

Three scaffolds of rhBMP-2 + coral, collagen + rhBMP-2 + coral and MSCs+collagen+rhBMP-2+coral were fabricated. Forty New Zealand rabbits were made the models of critical-sized defects and divided into 5 groups according to different implants: group I, auto-ilium; group II, coral; group III, rhBMP-2+coral; group IV, collagen+rhBMP-2+coral; and group V , MSCs+collagen+rhBMP-2+coral. Repair of bone defect was evaluated after 8 and 16 weeks of implantation by gross observation, X-ray, HE staining and Masson's trichrome staining.

RESULTS

Repair of bone defect in group V was similar to that in group I, and was better than that in group IV; and group III was worse. The gross appearance showed that defect region filled with bony tissue which had similar strength to adjacent bone and formed bone union with surrounding bone. The X-ray result displayed high radiopacity (80.45% +/- 2.52% in the 16th week). Histological observation showed new lamellar bone tissue and with few pore blank area. However, only transparent fibrous tissue filled the defect in group II.

CONCLUSION

Collagen may be a suitable sustained release system for rhBMP-2. And MSCs may have important effect on enhancing repair of bone defect. Tissue engineered bone fabricated by MSCs+collagen+rhBMP-2+coral may be a useful material for bone defect repair.

Anchoring Dental Implant in Tissue-Engineered Bone Using Composite Scaffold: A Preliminary Study in Nude Mouse Model

PURPOSE

The purpose of this study was to fabricate a tissue-engineered bone graft anchoring dental implant with bone marrow stromal cell (bMSC) seeded coral-implant composite scaffold.

MATERIALS AND METHODS

Titanium dental implants (3 mm in diameter) were inserted into the cylinder coral scaffolds (5 mm in diameter and 1 mm in wall thickness). bMSCs were isolated from iliac bone marrow of adult New Zealand White rabbits, induced by dexamethasone and seeded into the composite scaffold at the density of 2 x 10 8 /mL in 200 muL medium. Nine cell coral-implant complexes were incubated in vitro for 5 days. One complex was processed for scanning electronic microscopy. The other 8 complexes, together with 4 coral scaffold without cell acting as control, were implanted subcutaneously into nude mice back. At 1 and 2 months after implantation, 4 specimens from the experiment group and 2 specimens from the control group were harvested respectively. New bone restoration and new bone integration with dental implant were evaluated by gross inspection, manual handling test, radiographic examination, and histologic observation.

RESULTS

Specimens harvested at 2 months after implantation were red and similar to native bone. Manual handling test showed that dental implants were fixed in the newly formed bone. Radiographic examination showed that most of the coral scaffold had been absorbed. Bone density x-ray shadow could be observed around the dental implant. Histologic examination showed that large amount of new bone formed around the dental implants and integrated well with the implants in some area. In the control group no bone formation was observed both macroscopically and microscopically.

CONCLUSION

The results of the study suggested that the tissue-engineered bone of bMSCs seeded natural coral-implant composite scaffold is promising for dental implant anchoring, which has positive implication for clinical jaw reconstruction.