Tissue-engineered calcium phosphate cement in rabbit femoral condylar bone defects

Background  Calcium phosphate cement (CPC) is a favorable bone-graft substitute, with excellent biocompatibility and osteoconductivity. However, its reduced osteoinductive ability may limit the utility of CPC. To increase its osteoinductive potential, this study aimed to prepare tissue-engineered CPC and evaluate its use in the repair of bone defects. The fate of transplanted seed cells in vivo was observed at the same time.

Methods  Tissue-engineered CPC was prepared by seeding CPC with encapsulated bone mesenchymal stem cells (BMSCs) expressing recombinant human bone morphogenetic protein-2 (rhBMP-2) and green fluorescent protein (GFP). Tissue-engineered CPC and pure CPC were implanted into rabbit femoral condyle bone defects respectively. Twelve weeks later, radiographs, morphological observations, histomorphometrical evaluations, and in vivo tracing were performed.

Results  The radiographs revealed better absorption and faster new bone formation for tissue-engineered CPC than pure CPC. Morphological and histomorphometrical evaluations indicated that tissue-engineered CPC separated into numerous small blocks, with active absorption and reconstruction noted, whereas the residual CPC area was larger in the group treated with pure CPC. In the tissue-engineered CPC group, in vivo tracing revealed numerous cells expressing both GFP and rhBMP-2 that were distributed in the medullar cavity and on the surface of bony trabeculae.

Conclusion  Tissue-engineered CPC can effectively repair bone defects, with allogenic seeded cells able to grow and differentiate in vivo after transplantation.

     

mTOR inhibitor Abrogates Abnormal Osteoclastogensis in NF1

Background Neurofibromatosis Type 1 (NF1) is the most common genetic syndrome predisposing to various tumors due to dysregulation of Ras signaling pathway. Recent research has shown NF1 patients also suffer a spectrum of bone pathologies, which include abnormal skeletal development (scoliosis, congenital bowing, and congenital pseudoarthroses, etc), as well as a unique premature osteoporosis with increased fracture risk. The pathogenesis of NF1 bone diseases is largely unknown. There is no treatment currently. NF1 gene encodes the protein: neurofibromin, which is expressed in osteoblasts and osteoclasts. By using Nf1 heterozygote (Nf1+/-) mice and Nf1 conditional knockout mice, we and other groups demonstrated abnormal osteoblast and osteoclast function due to dysregulation of Ras signaling. However, the specific downstream effector pathways linked to NF1 abnormal osteoblastogenesis and osteoclastogenesis have not been defined. Methods We use Nf1+/+ and Nf1+/- mice as normal and NF1 model. Bone stromal cells extracted from Nf1+/+ and Nf1+/- mice were induced osteoclasts. The osteoclast cell was stained by TRAP staining. The osteoclast cell number was counted; the surface area of osteoclast cell was calculated under the microscope. The mRNA of mTOR was determined by qRT-PCR. The Phospho-Rib.S6 was determined by Western Blotting. Results Compared with Nf1+/+ mice, Nf1+/- mice had about 20% more of osteoclast cells. These osteoclasts cells were larger in size with more nuclei. Hyperactive mTOR was detected in Nf1+/- osteoclast cells. Inhibition of mTOR signaling by rapamycin in Nf1+/- OCLs abrogated abnormalities in cellular size and number. Conclusion These results suggest that mTOR pathway inhibition may represent a viable therapy for NF1 bone diseases.     

Reversal of multidrug resistance in renal cell carcinoma by short hairpin RNA targeting MDR1 gene

Background  Over-expression of P-glycoprotein (P-gp), encoded by the MDR1 gene, confers multidrug resistance (MDR) in renal cell carcinoma (RCC) and is a major reason for unsuccessful chemotherapy. This study aimed to determine the effct of RNA interference (RNAi) on the reversal of MDR in human RCC.

Methods  We designed and selected one short hairpin RNA (shRNA) targeting MDR1 gene, which is stably expressed from integrated plasmid and transfected by lentivirus fluid in human RCC A498 cell.

Results  The MDR1-targeted RNAi resulted in decreased MDR1 gene mRNA level (P <0.001), almost abolished P-gp expression and reversed MDR to different chemotherapy drugs in the RCC A498 cell line.

Conclusion  MDR could be reversed by RNAi in human RCC A498 cell line, which may be used for clinical application in future.

     

Proteomic analysis for detecting serum biomarkers related to smoking in humans

Background  Smoking is the leading cause of death in the world. This study focused on the difference of the serum proteomic profiling between healthy smokers and nonsmokers in order to find smoking-specific serum biomarkers.

Methods  Pattern-based proteomic profiling of 100 serum samples (from 50 Chinese male smokers and 50 matched nonsmokers) was performed through magnetic bead fractionation coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF-MS) and resulting data were statistically analyzed by Ciphergen ProteinChip software 3.0.2.

Results  We found 72 serum peaks were significantly different between smokers and nonsmokers (P <0.05). Marker peaks of mass-to-charge ratio (m/z) 3159.13, 7561.03 and 9407.32 were smoking-specific.

Conclusion  The preliminary data suggested that smoking-specific serum biomarkers could be detected in humans.

     

Reconstruction of segmental bone defects in the rabbit ulna using periosteum encapsulated mesenchymal stem cells-loaded poly(lactic-co-glycolic acid) scaffolds

Background  Repair of large bone defects remains a challenge for clinicians. The present study investigated the ability of mesenchymal stem cells (MSCs) and/or periosteum-loaded poly(lactic-co-glycolic acid) (PLGA) to promote new bone formation within rabbit ulnar segmental bone defects.

Methods  Rabbit bone marrow-derived MSCs (passage 3) were seeded onto porous PLGA scaffolds. Forty segmental bone defects, each 15 mm in length, were created in the rabbit ulna, from which periosteum was obtained. Bone defects were treated with either PLGA alone (group A), PLGA + MSCs (group B), periosteum-wrapped PLGA (group C) or periosteum-wrapped PLGA/MSCs (group D). At 6 and 12 weeks post-surgery, samples were detected by gross observation, radiological examination (X-ray and micro-CT) and histological analyses.

Results  Group D, comprising both periosteum and MSCs, showed better bone quality, higher X-ray scores and a greater amount of bone volume compared with the other three groups at each time point (P <0.05). No significant differences in radiological scores and amount of bone volume were found between groups B and C (P >0.05), both of which were significantly higher than group A (P <0.05). 

Conclusions  Implanted MSCs combined with periosteum have a synergistic effect on segmental bone regeneration and that periosteum plays a critical role in the process. Fabrication of angiogenic and osteogenic cellular constructs or tissue-engineered periosteum will have broad applications in bone tissue engineering.

     

非肿瘤细胞凋亡引起肿瘤机体血清细胞色素C增高

Background  Neuroblastoma (NB) is one of the most common malignant solid tumors of childhood. It is still not clear whether the apoptosis of tumor cells or the non-tumor cells contributes to the increase of concentration of cytochrome c (Cyt c) in the serum of the cancer patients. The aim of this research was to identify the source of the Cyt c in the serum when the tumor grows up by subcutaneous inoculation of human NB cells into nude mice.

Methods  We subcutaneously inoculated human NB cells (KP-N-NS) into nude mice and collected the sera of tumor-bearing mice (n=14) and control mice (n=25) 4 weeks later in order to screen for and identify differentially expressed proteins in the serum. Differentially expressed proteins in the serum were screened by surface-enhanced laser desorption/ionization-time-of-flight (SELDI-TOF) mass spectrometry.

Results  The relative intensity of a protein having a mass-to-charge ratio (m/z) of 11 609 was 3338.37±3410.85 in the tumor group and 59.84±40.74 in the control group, indicating that the expression level of this protein in the tumor group was 55.8 times higher than that in the control group. Serum proteins were separated and purified by high-performance liquid chromatography (HPLC). Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was performed to produce peptide mass fingerprints (PMFs). Spectrum analysis and a database search revealed that the highly expressed protein (m/z=11 605.4) from the serum of tumor-bearing mice was the mouse Cyt c.

Conclusions  Increased concentration of Cyt c in the serum of tumor-bearing nude mice might be partially attributed to the secretion of this protein by non-tumor cells.

     

Effect of peritumoral injection of boanmycin hydrochloride within temperature-sensitive in situ gel using Hep-G2 hepatoma nude mice model

Background  Boanmycin hydrochloride, a new antitumor agent, has a short half-life and fast clearance speed in vivo. The aim of this research was to investigate the effectiveness of peritumor injection of boanmycin hydrochloride within temperature-sensitive gel in situ using Hep-G2 hepatoma nude mice model.

Methods  Nude mice with human Hep-G2 tumor in right flank were randomly divided into four groups: normal saline group, in situ gel only group, boanmycin hydrochloride in situ saline group, and boanmycin hydrochloride in situ gel group, and were treated with injection of corresponding agents into peripheral tissue of the tumor. The volume of the tumor and the body weight of the mice were regularly measured, and tumor growth curve was generated. The size, internal echo, and blood flow of the tumors were observed by color Doppler ultrasonography. Histopathologic changes of the tumor after treatment were observed under both optical and transmission electron microscopy.

Results  The tumor growth was significantly inhibited by peritumoral therapy in boanmycin hydrochloride in situ gel group with the tumor inhibitory rate of 86.76%. The blood flow of the tumor was still seen in both normal saline group and in situ gel only group on color Doppler ultrasound. Punctate calcification and dotted blood flow were seen in boanmycin hydrochloride group; however, there was massive calcification and no blood flow in the tumor in the boanmycin hydrochloride in situ gel group. Large areas of necrosis and apoptotic cells were shown by microscopic observation in boanmycin hydrochloride in situ gel group.

Conclusion  Temperature-sensitive boanmycin hydrochloride in situ gel can effectively delay the release of boanmycin hydrochloride and increase its anticancer effects for liver cancer in animal model.

     

Immature CD4+ dendritic cells conditioned with donor kidney antigen prolong renal allograft survival in rats

Background  Allogeneic transplant rejection is currently a major problem encountered during organ transplantation. The dendritic cell (DC) is the most effective powerful known professional antigen-presenting cell, and recent studies have found that DCs can also induce immune tolerance, and avoid or reduce the degree of transplant rejection. The aim of this study was to evaluate the effect of transfused immature CD4⁺ DCs on renal allografts in the rat model.

Methods  In this study, we induced CD4⁺ immature DCs from rat bone marrow cells by a cytokine cocktail. The immature CD4⁺ DCs were identified by morphological analysis and then the suppressive activity of these cells conditioned with donor kidney antigen was evaluated in vitro and in vivo.

Results  Immature CD4⁺ DCs conditioned with donor kidney antigen possessed immunosuppressive activity in vitro and they were able to prolong renal transplant survival in an allograft rat model in vivo.

Conclusions  Our study provides new information on efficacious renal transplantation, which might be useful for understanding the function of immature CD4⁺ DCs in modulating renal transplant rejection and improving clinical outcome in future studies.

     

Endothelial progenitor cell down-regulation in a mouse model of Kawasaki disease

Background  Cardiovascular complications of Kawasaki disease (KD) are a common cause of heart disease in pediatric populations. Previous studies have suggested a role for endothelial progenitor cells (EPCs) in coronary artery lesions associated with KD. However, long-term observations of EPCs during the natural progression of this disorder are lacking. Using an experimental model of KD, we aimed to determine whether the coronary artery lesions are associated with down-regulation of EPCs.

Methods  To induce KD, C57BL/6 mice were administered an intraperitoneal injection of Lactobacillus casei cell wall extract (LCWE; phosphate buffered saline used as control vehicle). Study groups included: group A (14 days following LCWE injection), group B (56 days following LCWE injection) and group C (controls). Numbers of circulating EPCs (positively staining for both CD34 and Flk-1 while staining negative for CD45) were evaluated using flow cytometry. Bone marrow mononuclear cells were cultured in vitro to expand EPCs for functional analysis. In vitro EPC proliferation, adhesion and migration were assessed.

Results  The model was shown to exhibit similar coronary artery lesions to KD patients with coronary aneurysms. Numbers of circulating EPCs decreased significantly in the KD models (groups A and B) compared to controls ((0.017±0.008)% vs. (0.028±0.007)%, P <0.05 and (0.016±0.007)% vs. (0.028±0.007)%, P <0.05). Proliferative, adhesive and migratory properties of EPCs were markedly impaired in groups A and B.

Conclusion  Coronary artery lesions in KD occur as a consequence of impaired vascular injury repair, resulting from excess consumption of EPCs together with a functional impairment of bone marrow EPCs and their precursors.

     

LRP16 gene protects mouse insulinoma MIN6 cells against fatty acid-induced apoptosis through Akt/FoxO1 signaling

Background  Pancreatic b cells are susceptible to fatty acid-induced apoptosis. The 17b-estradiol (E2) protects pancreatic b cells from apoptosis, mediated by the estrogen receptor-a (ERa). The mRNA level and promoter activity of leukemia-related protein (LRP) 16 were significantly increased by E2 in ER-a and LRP16 was a co-activator of ER-a. The aim of the study was to assess the effects of LRP16 on fatty acid-induced apoptosis in MIN6 cells.

Methods  Cells with over-expressing LRP16 were obtained by lipidosome transfection. Insulin content and glucose-stimulated insulin secretion (GSIS) were examined by radioimmunoassay. Western blotting was applied to detect protein expression. Apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry. The forkhead boxO1 (FoxO1) subcellular localization was determined by immunocytochemical analysis.

Results  MIN6-LRP16 cells with overexpression of LRP16 were successfully established, and protein expression of LRP16 was 2.29-fold of that of control cells (MIN6-3.1, P <0.05). Insulin content and GSIS in MIN6-LRP16 were substantially increased compared with those in control cells. When cells were stimulated with glucose, increased phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and serine-threonine kinase (Akt) were observed in MIN6-LRP16. When cells were under palmitate pressure, the TUNEL-positive rate in MIN6-LRP16 was (17.0±0.5)%, while it in MIN6-3.1 was (22.0±0.4)%. In palmitate-treated cells, attenuated Akt phosphorylation was observed, but the attenuation in Akt activity was partially restored in MIN6-LRP16 cells. Meanwhile, nuclear localization of FoxO1 in MIN6-LRP16 was apparently reduced compared with that in control cells.

Conclusions  LRP16 regulated insulin content and GSIS in MIN6 cells by ERK1/2 and Akt activated way. Meanwhile, LRP16 overexpression protected MIN6 cells from fatty acid-induced apoptosis by partially restoring Akt phosphorylation and inhibiting FoxO1 nuclear redistribution. Therefore, LRP16 played important roles not only in insulin content and GSIS but also in the antilipotoxic effect mediated by Akt /FoxO1 signaling.

     

Effect of chronic intermittent hypoxia on theophylline metabolism in mouse liver

Background Chronic intermittent hypoxia (CIH) has been associated with abnormalities in the liver,which is the most important organ for drug metabolism.This study aimed to investigate the effect of CIH...     

HLA-DR expression on regulatory T cells is closely associated with the global immune activation in HIV-1 infected subjects naïve to antiretroviral therapy

Background  The frequencies of regulatory T cells (Tregs) increased over the HIV infection but its counts actually decreased. We proposed that the decrease of Treg counts may cause the reduction of inhibitory effect and thereby account for the over-activation of Tregs during HIV infection. However, it remains unknown whether Tregs are also over-activated and thereafter the activation induced death may lead to the decrease of Tregs.

Methods  Tregs were defined as CD4⁺CD25⁺CD127^lo/- T cells. Eighty-one HIV-1 infected patients were enrolled in our study, and twenty-two HIV-1 seronegative donors were recruited as the control. The levels of HLA-DR on Tregs were determined by FACSAria flow cytometer.

Results  Compared to HIV-1 seronegative donors, the levels of HLA-DR on CD4⁺CD25⁺CD127^lo/- Tregs were significantly increased in HIV-1 infected patients, and its increase was positively associated with viral loads (r=0.3163, P=0.004) and negatively with CD4 T-cell counts (r=−0.4153, P <0.0001). In addition, significant associations between HLA-DR expression on CD4⁺CD25⁺CD127^lo/- Tregs and the percentages of HLA-DR, CD38, Ki67 expressing CD4⁺ and CD8⁺ T cells were also identified.

Conclusion  HLA-DR on Tregs is a good marker for viral replication and disease progression. The over-activation of Tregs might result in the decrease of Tregs.

     

Role of microRNA-181a in the apoptosis of tubular epithelial cell induced by cisplatin 

Background  Cisplatin (DDP) is one of most effective and most commonly used therapeutic agent in treating tumors, it can accumulate in the kidney and lead to acute renal failure. MicroRNA-181a can induce cell apoptosis by suppressing the expression of Bcl-2 family. In the present study, we investigated the role of microRNA-181a in the apoptosis of tubular epithelial cell induced by DDP.

Methods  HK-2 cells were cultured, transfected with microRNA-181a inhibitor for 48 hours, and stimulated with 50 µmol/L cisplatin for 24 hours. MicroRNA-181a expression was analyzed by real time PCR, and cell apoptosis was detected by flow cytometry. Moreover, Bcl-2 and Bcl-2-associated X protein (Bax) expression were measured by Western blotting.

Results  MicroRNA-181a expression significantly down-regulated in cells transfected with microRNA-181a inhibitor, compared with that in untransfectd cells (21.19±2.01 vs. 38.87±1.97, P <0.05). Cell apoptosis induced by DDP significantly decreased in cells transfected with MicroRNA-181a inhibitor. Compared with DDP treated cells alone, Bcl-2 expression strikingly was up-regulated and Bax expression was down-regulated in cells transfected with microRNA-181a inhibitor.

Conclusion  One pathway of DDP induces apoptosis of tubular epithelial cell by suppressing Bcl-2 expression is achieved by regulating the target gene of MicroRNA-181a.

     

Gene delivery in peritoneal dialysis related peritoneal fibrosis research

Objective  To summarize the development of gene delivery vectors in peritoneal fibrosis research and discuss the feasibility and superiority of lentiviral vectors.

Data sources  The data in this article were collected from PubMed database with relevant English articles published from 1995 to 2011.

Study selection  Articles regarding the gene therapy in peritoneal fibrosis research using non-viral vectors, adenoviral vectors, retroviral vectors, and lentiviral vectors were selected. Data were mainly extracted from 60 articles, which are listed in the reference section of this review.

Results  Non-viral vector-mediated gene delivery (including naked DNA for ex vivo, oligonucleotides, ultrasound- contrast agent mediated naked gene delivery, etc.) and viral vector-mediated gene delivery (including adenovirus, helper-dependant adenovirus, and retrovirus vectors) have been successfully applied both in the mechanistic investigation and the potential prevention and treatment of peritoneal fibrosis.

Conclusions  Peritoneal fibrosis is a major complication of peritoneal dialysis (PD). Recently, the wide use of the gene delivery technique made it possible to access and further research peritoneal fibrosis. The use of lentiviral vector is expected to be widely used in PD research in the future due to its advantages in gene delivery.

     

Abnormal mitochondrial function impairs calcium influx in diabetic mouse pancreatic beta cells

Background  Abnormal insulin secretion of pancreatic beta cells is now regarded as the more primary defect than the insulin function in the etiology of type 2 diabetes. Previous studies found impaired mitochondrial function and impaired Ca²⁺ influx in beta cells in diabetic patients and animal models, suggesting a role for these processes in proper insulin secretion. The aim of this study was to investigate the detailed relationship of mitochondrial function, Ca²⁺ influx, and defective insulin secretion.

Methods  We investigated mitochondrial function and morphology in pancreatic beta cell of diabetic KK-Ay mice and C57BL/6J mice. Two types of Ca²⁺ channel activities, L-type and store-operated Ca²⁺ (SOC), were evaluated using whole-cell patch-clamp recording. The glucose induced Ca²⁺ influx was measured by a non-invasive micro-test technique (NMT).

Results  Mitochondria in KK-Ay mice pancreatic beta cells were swollen with disordered cristae, and mitochondrial function decreased compared with C57BL/6J mice. Ca²⁺ channel activity was increased and glucose induced Ca²⁺ influx was impaired, but could be recovered by genipin.

Conclusion  Defective mitochondrial function in diabetic mice pancreatic beta cells is a key cause of abnormal insulin secretion by altering Ca²⁺ influx, but not via Ca²⁺ channel activity.

     

Association of NFATc1 gene polymorphism with ventricular septal defect in the Chinese Han population

Background Congenital heart disease (CHD) is a diverse group of diseases determined by genetic and environmental factors.Considerable research has been done on genes associated with the development of ...     

Transitional cell carcinoma associated with aristolochic acid nephropathy: most common cancer in chronic hemodialysis patients in China

Background  The research of cancer in patients on hemodialysis (HD) in China has not been reported. The aim of this study was to investigate the clinical and histological features and outcomes of cancer in Chinese HD patients.

Methods  The study subjects were 49 cancer patients (1.4%) out of 3448 end stage renal disease (ESRD) patients maintained on HD at China-Japan Friendship Hospital from October 1997 to July 2011.

Results  Urinary tract cancer (74%) was the most common followed by gastrointestinal tract cancer (12%), breast cancer (6%), lung cancer (4%), thyroid cancer (2%), and hematologic cancer (2%). Thirty-three patients (67%) had urinary tract transitional cell carcinoma (TCC) and 29 of them had aristolochic acid nephropathy (AAN) as underlying disease. Death occurred in eight patients out of 49, and the survival rate of HD patients with cancer was similar to those without cancer (P=0.120).

Conclusion  The urinary tract TCC is the most common cancer in HD patients with AAN in one of the centers of northern China.

     

创伤骨科患者创伤严重程度和血浆D二聚体水平的相关分析

Background  The correlation between the plasma D-dimer level and deep vein thrombosis has not been conclusive in various studies. The aim of this research was to study the relationship between plasma D-dimer levels and the severity of orthopedic trauma by retrospective examination of orthopedic trauma cases.

Methods  Clinically acute trauma and non-acute trauma patients were selected and their plasma D-dimer levels were measured. Plasma D-dimer levels in patients of these two groups were compared. The relationship between the plasma D-dimer level and the severity of the trauma was also studied.

Results  There were 548 cases in the acute trauma group and 501 cases in the non-acute trauma group. The levels of plasma D-dimer were significantly higher in the acute trauma group than in the non-acute trauma group (P <0.01). In the acute trauma group, the correlation between the D-dimer level and the number of fractures was a positive linear correlation (r=0.9532).

Conclusions  Elevated plasma D-dimer is common in trauma patients. The D-dimer level and the number of fractures in the trauma patients are closely correlated. D-dimer is not only an indicator for the diagnosis of deep vein thrombosis and pulmonary embolus, but also an indicator of the severity of trauma in acute trauma patients.