Construction and vascularization of tissue-engineered sinus node in cardiac tissue engineering / 中国组织工程研究

BACKGROUND: As in theory tissue-engineered sinus node can establish a new pacemaker in vivo when implanted into the human body, it is a promising treatment for sick sinus syndrome. But this method is immature and needs to be explored in depth. OBJECTIVE: To overview the different construction methods of tissue-engineered sinus node, and the research progress of vascularization in cardiac tissue engineering. METHODS: A computer-based retrieval in PubMed and CNKI databases was performed by the first author to search related papers published from 1984 to 2016 using the keywords of vascularize, tissue engineering, sinus node in English and Chinese, respectively. We summarized the construction methods of tissue-engineered sinus node and importance of vascularization in cardiac tissue engineering. RESULTS AND CONCLUSION: Sinus node cells, bone marrow mesenchymal stem cells, adipose-derived mesenchymal stem cells and embryonic stem cells can be used as seed cells. There are a variety of materials used for constructing tissue-engineered scaffolds, among which, collagen is the best choice. Three-dimensional printing technology and cell-sheet techbology make it possible to construct and transplant tissue-engineered sinus node. The early blood supply is the key for the successful sinus node transplantation. However, the vascularized tissue-engineered sinus node has not yet been reported. Endothelial progenitor cells can promote angiogenesis, but further explorations are warranted as there are some existing defects.

Discussion on bilingual teaching mode of anatomy for international medical students in the same class teaching / 中华医学教育探索杂志

Objective To explore suitable anatomy for teaching methods for international medical students from multiple sources. Methods Thirteen international medical students of 6-year-programme (grade 2011) and 19 Chinese medical students of five-year-programme were taught with Chinese system anatomy(module) textbooks and Chinese-English bilingual textbook(as reference) by three-step bilingual anatomy teaching method , which includes previewing anatomical vocabulary , teaching Chinese and foreign students in the same class. Teaching effect was international tested by scale separating teaching and examing and questionnaire survey. SPSS 10.0 was used to do statistical analysis and t test was used to compare the score of Chinese medical students and international med-ical students. P<0.05 students for statistic difference. Results Average test scores of international and Chinese students in the same class were 86.2 and 88.1 respectively, with no significant difference (P﹥0.05). 92.3%(12/13) international students were satisfied with this teaching method and the same class teaching for Chinese and international students . Conclusions Three-step bilingual anatomy teaching method in the same class may be more suitable for international students from multiple sources and this teaching method is worthy of further study and practice.

Role and mechanism of retinoic acid in axonal regeneration / 中国组织工程研究

BACKGROUND:Retinoic acid signaling pathways is very important in the formation pf nervous system, specialization of neurons and outgrowth of axons. The recent studies show that, retinoic acid plays an important role in the process of axonal regeneration, but few research reports its exact molecular mechanism. OBJECTIVE:To analyze and summarize the mechanism underlying retinoic acid signaling pathways in the process of axonal regeneration. METHODS:A computer-based online research was conducted among the VIP, CNKI, PubMed, BioMed Centeral, Springer, The Free Medical Journals, EBSCO and Foreign Journals Integration System between January 2000 and December 2013, with the key words of“retinoic acid, the central nervous system, nerve damage, axon regeneration, and mechanism”in Chinese and English. A total of 43 studies addressing the molecular mechanism of retinoic acid in axonal regeneration were screened. According to the supplementary documents, another five references were added. Repetitive research and atypical reports were excluded. RESULTS AND CONCLUSION:Fol owing acute central nervous system injury, axonal regeneration and functional recovery are extremely limited. For proper functionality fol owing injury, axons must regrow, reinnervate their targets, and remyelinate their axons. When the central nervous system injuries occur, retinoic acid signaling pathways express transcription factor retinoic acid receptorβ2 to induce axonal regeneration fol owing injury;in dorsal root ganglion neurons, cAMP levels are greatly increased by lentiviral retinoic acid receptorβ2 expression and contribute to neurite outgrowth. More recently, retinoic acid-retinoic acid receptorβ2 pathways directly transcriptional y repress a member of the inhibitory Nogo receptor complex, Lingo-1, under an axonal growth inhibitory environment in vitro as wel as fol owing spinal cord injury in vivo. Through these molecular mechanisms, retinoic acid signaling pathways play its important role in the process of axonal regeneration.

Anatomical research and clinical application of anterior approach for pelvic and acetabular fractures / 中华创伤杂志

Objective To perform an anatomical study on anterior approach to fractures of the pelvis and acetabulum in an attempt to testify feasibility of the approach.Methods Position and variation of anatomical structure of the hypogastric abdominal wall and pelvic cavity were observed in 10 cadaveric adults (20 sides).Based on the anatomical study,anterior approach to pelvic fractures (n =20)and acetabular fractures (n =15) were performed and clinical results were observed.Results Anterior pelvic incision revealed no splitting or exposure of the spermatic cord/round ligament of uterus.Vertical incision through the muscle layer of abdominal wall located at lateral rectus abdominis and medial initial segment of hypogastric arteries/veins.In clinical practice,the approach revealed the mean incision length of 10 cm (range,9-12 cm) and mean blood loss of (225.5 ± 30.5) ml (range,170-350 ml).No injuries to femoral nerve and sciatic nerve occurred and there was no deep vein thrombosis.Surgical incision healed primarily.Bone union were recorded at the 18-month follow-up (11-35 months).Conclusions Anterior pelvic approach stretches the operative field from pubic symphysis to anterior-lateral cacroiliac joint and quadrilateral surface,allowing full exposure of the fracture site.The approach has benefits of high safety,minor trauma,large exposure,and satisfactory results and hence deserves wide application in clinical settings.

Current research and development of tissue engineered venous valve / 中国组织工程研究

OBJECTIVE: To review the current research of tissue engineered venous valve at home and abroad, to analyze the developing trend of tissue engineered venous valve in the clinical application.METHODS: A computer retrieve was performed among PubMed, ProQuest Health & Medical Complete database, Springer English Academic Journal Full-text database, Elsevier Full-text database between January 2000 and August 2009, with the key words of "tissue engineering venous valve", and the language was limited to English. At the same time, Chongqing VIP database, Qinghua Academic Journals Database, Chinese Biomedical Literature database were also screened on computer by using the

Differentiation of bone marrow mesenchymal stem cells co-cultured with endothelial cells under shear stress / 生物医学工程学杂志

Differentiation of bone marrow mesenchymal stem cells (BMSCs) co-cultured with endothelial cells (ECs) under shear stress was studied. BMSCs and ECs were co-cultured on the two sides of PET membrane, and 20 dyn/cm2 shear stress produced by parallel plate flow chamber was performed after 72 hours. Cell morphology was observed under phase-difference microscope, and the expressions of smooth muscle-alpha-actin (SM-alpha-actin), calponin and smooth muscle myosin heavy chain (SMMHC) of BMSCs were detected by fluorescence immunocytochemistry. The co-cultured BMSCs became smooth muscle-like cells gradually; after 24 hours, the BMSCs started to express SM-alpha-actin. After 48 hours, they expressed SM-alpha-actin and calponin obviously. After 72 hours, obvious expressions of SM-alpha-actin and calponin, but not of SMMHC, were detected. Further static co-culture had no effect on SM-alpha-actin, calponin and SMMH expression of BMSCs; after 24 hours, shear stress induced feeble expression of SM-alpha-actin and obvious expression of SMMHC in co-cultured BMSCs, but it had no effect on the expression of calponin. The results suggest that shear stress may potentiate the differentiation of BMSCs (co-cultured with ECs) into mature smooth muscle-like cells.

Identification of neural tissue-committed stem cells, a new cellular group, in bone marrow / 中国组织工程研究

BACKGROUND: It has been widely accepted that both bone marrow-derived mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) have the capacity to differentiate into neural lineages. Some scholars believe that in addition to HSCs and MSCs, bone marrow (BM) also harbors a highly mobile population of CXCR4+ tissue committed stem cells (TCSCs), including skeletal muscles, heart, liver, and neural tissue. OBJECTIVE: To make sure that neural tissue-committed stem cells (NTCSCs) reside in the bone marrow, and to establish a purification and culture method for bone marrow-derived NTCSCs.DESIGN: Opening animal study.SETTING: Department of Anatomy, the Second Military Medical University of Chinese PLA. MATERIALS: Adult Sprague-Dawley (SD) rats (pathogen-free) were provided by the Animal Center of the Second Military Medical University of Chinese PLA. Dulbecco's modified eagle's medium (DMEM)/F12, B27, N2 and epidermal growth factor (EGF, Invitrogen Company), basic fibroblast growth factor (bFGF, CytoLab Ltd), rabbit anti-rat Nestin,CXCR4, β-Tublin Ⅲ, glial fibrillary acidic protein (GFAP, Santa Cruz Company), mouse anti-rat microtubule associated protein 2ab (MAP2ab) (Clone11-5B), cyclic nucleotide 3'phosphohydrolase (CNPase, Clone AP20, NeoMarkers Company), fluorescent(fluorescein isothiocyanate, Cy3) marker reagents (Wuhan Boster Bioengineering Co., Ltd), nuclear fluorescent dyes 4,6-diamidino-2-phenylindole(DAPI)(Sigma), immunohistochemistry reagents (Vector Laboratories Company) , and NycoPrepTM separation liquid (1.077A, Axis-Shield Company) were used in this study.METHODS: This study was performed in the Department of Anatomy, the Second Military Medical University of Chinese PLA from January 2004 to December 2006. Bone marrow was harvested from bilateral femurs and tibias of 2-3 weeks SD rats. Mononuclear cell layer was isolated by NycoPrepTM separation liquid and suspended in DMEM/F12(1:1)serum-free medium supplemented with 2% B27,1% N2, 20 μg/L bFGF, 20μg/L EGF, 1×105 U/L penicillin and 100 mg/L streptomycin. NTCSCs were isolated and propagated by suspensive growing from adherent cells in bone marrow in DMEM/F12 free-serum medium. MAIN OUTCOME MEASURES: NTCSCs were identified by immunocytochemistry for CXCR4, a marker of TCSCs and nestin, a marker of neural stem cells, and neural lineages marker protein after differentiation of cellular spheres. RESULTS: The NTCSCs spheres expressed nestin, a neural stem cell marker as well as CXCR4, a marker of TCSCs. The NTCSCs' spheres were naturally differentiated in DMEM medium with 15% fetal bovine serum. The differentiated cells expressed β-Tublin Ⅲ, MAP2ab, CNPase and GFAP, markers of neural lineages. CONCLUSION: NTCSCs reside in bone marrow and naturally differentiate into neural lineages in vitro.

Reconstruction of bowel and bladder function in paraplegic patients by vascularized intercostal nerve transfer to sacral nerve roots with selected interfascicular anastomosis / 中国组织工程研究

BACKGROUND: Independent urination and defection functions do not exist in patients with paraplegia above T12 because the injury disrupts the connection to the brain.OBJECTIVE: To reconstruct urination and defecation functions in patients with paraplegia with vascularized intercostal nerve transfer to sacral nerve roots with selected interfascicular anastomosis.DESIGN: Self-control observation.SETFING: Department of Orthopedics, Changhai Hospital of the Second Military Medical University of Chinese PLA.PARTICIPANTS: We recruited 30 patients with traumatic paraplegia at T9-L2 who received treatment in the Department of Orthopedics,Changhai Hospital of the Second Military Medical University of Chinese PLA, from January 1990 to December 2000. Paraplegia plane at T9-T11was found in 17 cases and paraplegia plane at T12-L2 in 13 cases. All the cases had undergone vertebral lamina decompression and internal fixation, 24 of whom had an additional operation to remove the internal fixation.METHODS: Two normal vascularized intercoastal nerves and artery and vein (intercostals nerves were generally at ribs 7 and 8 or 9 and10)above the spinal cord injury site were harvested by cutting in at their distal ends at the midclavicular line and separating the proximal ends from the levatores costarum. The nerves were then transferred to the vertebral canal through a submuscular tunnel. A sural nerve segment that had been harvested and sheared into two segments was sutured to the intercostal nerves by epiperineurial neurorrhaphy and then to the S2-4nerve roots by interfascicular neurorrhaphy. For patients with spinal injury plane below T11, intercostal nerve or subcostal nerve among the 10th and 11th ribs were harvested from the incision of abnormal wall. The nerves were transferred to the lumbar part through the channel of lateral abdominal wall. The transplanted sural nerve was conrected to S2-4 nerve root of partial nerve tract cut alternatively and exposed from S1,2 plane posterior. Defecation function of the patients was evaluated at postoperative 1, 3, 6, 12 and 24 months and follow-up; urodynamic examination was performed before and after operation.patients.RESULTS: A total of 30 patients were followed up for 5 years on average,tion and defecation functions of the patients: 26 (86.6%) had recovered defecation and urination sensation, 23 (76.7%)regained the micturition reflex and uriesthesis; 19 (63%) had recovered function of the detrusor The postoperative maximum urine flow ratio, surplus urine volume, and the maximum systolic pressure of detrusor muscle were obviously improved as compared with those before operation [(12.0±3.0) vs (2.0±0.3) mL/s,(80±12) vs (150±30) mL, (11.76±3.43) vs (5.88±1.47) kPa, P ＜ 0.05]. Postoperative low compliance was found in 9 cases, and detrusor areflexia in 7cases. The number was both significantly decreased as compared with that of preoperative cases (26 and 27 respectively).CONCLUSION: Transfer of vascularized intercostal nerve to S2-4 nerve roots with selected interfascicular anastomosis can reconstruct partial urination and defecation functions, and sensation in buttock, perineal region and cunnus region in paraplegia.

Electro-acupuncture on Du meridian up-regulates the expression of Bcl-2 mRNA and its protein in early spinal cord injury of rats / 中国组织工程研究

BACKGROUND: It is proved that acupuncture can remarkably promote recovery of nervous function after spinal cord injury (SCI). Previous studies in our groups have been proved that electro-acupuncture can inhibit apoptosis in early period of SCI, but the mechanism is unclear yet.OBJECTIVE: To study the effect of electro-acupuncture on expressions of apoptosis inhibitory gene Bcl-2 mRNA and protein with hybridization in situ and immunohistochemistry and discuss the possible mechanism of apoptosis inhibited by electro-acupuncture in early SCI.DESIGN:Opening animal study.SETTING: Department of Anatomy, the Second Military Medical University of Chinese PLA; Shanghai Acupuncture & Moxibustion and Meridian Research Center.MATERIALS:Adult male SD rats of pathogen-free aged 2-3 months were selected in this study. Bcl-2 hybridization in situ kit was provided by Wuhan Boshide Biotechnology Company Limited and Bcl-2 antibody (1:200) was provided by Santa Cruz Biotechnology Company.METHODS: The experiment was completed at the Laboratory of Anatomy of the Second Military Medical University of Chinese PLA from July 2004 to December 2005. All experimental rats were randomly divided into model group, electro-acupuncture group, methylprednisolone group and sham operation group. T10 spinal cord was injuried by the modified Allen's method and treated with electro-acupuncture immediately, and then the expressions of Bcl-2 mRNA and protein were evaluated with hybridization in situ and immunohistochemistry combined with image quantitative analysis.MAIN OUTCOME MEASURES: ① Expressions of Bcl-2 mRNA and protein in early SCI; ② effect of electro-acupuncture on expressions of Bcl-2 mRNA and protein.RESULTS: The rats were supplied when they died during the experiment,and all 42 rats were involved in the final analysis. ① Moderate expression of Bcl-2 mRNA and protein was observed in the sham operation group.Expression of Bcl-2 mRNA was increased in model group at 6 hours after SCI, but expression ofBcl-2 protein was not changed. At 24 hours after SCI, both expressions of Bcl-2 mRNA and Bcl-2 protein were increased.Expression of Bcl-2 mRNA and protein was higher in electro-acupuncture group than that in mo del group (P ＜ 0.05), and there was no significant difference from that in methylprednisolone group. ② Amount of positive Bcl-2 mRNA cells was increased in electro-acupuncture group and methylprednisolone group at 6 hours after treatment, and gray value was decreased.There was significant and remarkably significant difference from those in sham operation group and model group, respectively (P ＜ 0.05-0.01). After 24-hour treatment, amount of positive Bcl-2 mRNA cells was increased in electro-acupuncture group and gray value was decreased.There was significant and remarkably significant difference from those in sham operation group and model group, respectively (P ＜ 0.05-0.01). ③ After 24-hour treatment, amount of immunohistochenistry positive Bcl-2 cells was increased in electro-acupuncture group and gray value was decreased. There was significant and remarkably significant difference from those in sham operation group and model group, respectively (P ＜ 0.05-0.01).CONCLUSION: Electro-acupuncture can up-regulate the expressions of Bcl-2 mRNA and protein so as to inhibit apoptosis in early SCI.

Remodeling of retinal microvessels in STZ-induced diabetic rats and medical influence / 第二军医大学学报

Objective: To observe the remodeling of diabetic microvessels in diabetic rats. Methods: Diabetic animal models were induced by STZ on SD rats. The rats were treated with nonenzymatic glycosylation inhibitor and blood flow activating and stasis removing traditional Chinese medicine to evaluate the remodeling of diabetic retinal microvessels by trypsin digestion and figure analysis. Results: At 8 weeks, significant alteration of retinal capillary width in diabetic rats were observed( P

Angiogenesis stimulated by platelet-derived growth factor in aged mice / 第二军医大学学报

Objective:To investigate the role of platelet-derived growth factor(PDGF)-AB on angiogenensis in aged mice.Methods:Cardiac microvascular endothelial cells(CMEC)from the hearts of young adult and old mice were cultured.Expression of PDGF-BB and PDGF-AA was detected by RT-PCR.The migration of CMEC was determined with ChemoTX Chamber.Ear angiogenesis model was made in mice.Blood flow in neo-microvessels and collateral vessels was measured with Laser Doppler.Then biotin-labeled Dextran-lysine was injected into the mice through cardiac puncture to label vessels.Ears were cut and immunohistochemistry was carried out by ABC method.Results:Both PDGF-BB and PDGF-AA were highly ex-pressed in CMEC of young adult mice;expression of PDGF-BB was not detected in aged mice.PDGF-AB reverted the levels of PDGF-BB in aged CMEC to the levels of young adult mice.Migration rate of CMEC in aged mice was significantly increased after stimulation by PDGF-AB(P

Expression of c-myc and cdc2 gene in hypercholesterolemic rabbit following iliac-femoral angioplasty / 第二军医大学学报

Objective:To investigate the expression of c myc and cdc2 gene in iliac femoral arteries of rabbits fed with high cholesterol diet. Methods:Totally 24 New Zealand rabbits fed with high cholesterol and high lipid diet were chosen for the experiment. In treated groups,the iliac femoral arteries were dilated by balloon catheter in 2 week high lipid diet fed rabbits. After 6 8 weeks,angiography was performed to detect the stenosis in iliac femoral,and ballon dilation was carried out when stenosis beyond 50%. Expression of c myc and cdc2 mRNA (24 h following balloon dilation) and their proteins (2 weeks following balloon dilation) were measured by means of RT PCR and immunohistochemistry (GISS) methods. Results: Expressions of c myc,cdc2 mRNA and their proteins in dilated arteries were all increased 24 h and 2 weeks following balloon dilation. Immuno positive particles were mainly located at nuclei of SMC in neotima layer,and a little at cytoplasma. Conclusion: Expressions of c myc,cdc2 mRNA and their proteins are increased in arteries following angioplasty. It is indicated that c myc and cdc2 may play an important role in neointimal formation after angioplasty.