Chest wall resection and reconstruction remains a severe challenge for reconstructive surgeons,which often leads to conservative treatment regimens in clinical practice,consequently resulting in poor outcomes(high morbidity and mortality).In recent 20 years,advances in muscle flap surgery and availability of chest reconstructive prosthesis have encouraged the surgeons to take an active attitude toward chest wall resection;many "unresectable" lesions now have a chance to be resected and cured.This article reviews the problems concerning the principles for chest wall resection,reconstruction,prosthesis selection,etc.in chest wall reconstruction.

Objective To investigate the application of a novel degradable biomaterial artificial chest wall as a chest wall prosthesis and explore the feasibility of its use in chest wall reconstruction. Methods A full-thickness chest wall defect of 10?10 cm was created in 8 dogs and then repaired with short chitin fiber reinforced polycaprolactone (PCL) plate. The situation of the implanted chest wall prosthesis and the progress of the regeneration of the chest wall tissue were observed dynamically postoperatively by X-ray, CT and histological examinations. Results No operative and peri-operative deaths were observed, no flail chest and paradoxical movement, no infection and severe complications occurred. Artificial chest wall prosthetic integrated tightly with chest wall ribs and muscle tissue around. New bone tissue obviously regenerated around both resection ends of the ribs in 4 months. The chest wall prosthesis was tightly enveloped by thick fibrous tissue in 6 months. Conclusion Degradable chitin fiber reinforced PCL biomaterial has excellent properties such as fine biocompatibility, optimal mechanical properties, fine flexibility and elasticity and translucent to X-rays. It is a prospective material for chest wall reconstruction.

Objective To design and prepare a new prosthesis of chest wall by selecting and integrating the appropriate biodegradable materials,and to evaluate the efficiency and safety of the prepared prosthesis in order to explore the feasibility of reconstruction of an extensive chest wall defect.Methods Three types of chest wall prostheses,polydioxanone(PDO)mesh,chitin fiber reinforced polycaprolactone(CFRP)plate and CFRP strip,were designed and prepared to fulfill the function of chest wall.A canine model of the chest wall resection and reconstruction was reproduced to evaluate these porstheses.15 adult mongrel dogs were subjected to extensive resection of anterior-lateral chest wall and reconstruction with chest wall prosthesis.Chest wall stability,the degradative process of the prosthetic materials and regeneration of the chest wall tissue postoperatively were recorded dynamically by macroscopic inspection and histopathologic examinations,so as to provide valuable scientific data for improving chest wall prosthesis.Results The implanted PDO mesh was well integrated with autogenous connective tissue 8 weeks after operation,degraded gradually and reabsorbed completely within 24 weeks.It provided adequate support to the chest wall and achieved satisfy cosmetic and functional repair.CFRP plate was the best in chest wall stabilization among the three groups,and paradoxical respiratory movement was efficiently relieved with CFRP rib,and it had a better biological compatibility.There was no obvious morphological change in the CFRP material after it was implanted for 24 weeks.Conclusion The synthetic prostheses developed here showed excellent biocompatibility,and they fulfilled the function in providing chest wall stabilization.Each prosthesis has its respective favorable properties in chest wall reconstruction,and all of them are valuable in clinic application in the management of complicated chest wall defects.

Objective To investigate the effect of the transplantation of autologous marrow mesenchymal stem cells transfected by angiogenin gene in a porcine chronic ischemic beart model.Methods Methods Mesenchymal stem cells were trnsfected byAd/Ang.The pigs underwent placement of amerold occluder around LCx and 4 weeks later sujected to transplantation of the trandected mesenchymal stem cells.The animals were evaluated by coronary angiography,echocardiography,mannetic resonance imaging end pathologic observation.Results All animal showed 95%occlusion fo LCx.4 weeks after treatment ,the perfusion of LCx,left ventricular ejection fracton were greatly evhanced.A large number of labeled mesenchymal stem cells were successfully uncorporated into blood vessels in the ischemic myocardial regions with increased vessels countin and survival of implanted cell.Conclusion Transplantaton of autologous mesenchymal stem cells trendected by angiogenin gene offere obvious advsntases of great improvement of blood supply and the heart funcition.

BACKGROUND: Hyperpolarization-activated cyclic nucleotide-gated (HCN) current plays an important role in regulating heart spontaneous pulsation.OBJECTIVE: To observe target gene expression and electrophysiological characteristics of pig bone marrow mesenchymal stem cells (BMSCs) transfected with hyperpolarization-activated cyclic nucleotide-gated channel 2 (HCN2) gene recombinant adenovirus.DESIGN, TIME AND SETTING: Cell-gene in vitro study was performed at the Laboratory of Thoracic and Cardiovascular Surgery,Second Military Medical University of Chinese PLA from July 2007 to March 2008.MATERIALS: Yorkshire pig was supplied by Animal Institute, Second Military Medical University of Chinese PLA. HCN2 plasmid was presented by Professor Dario DiFrancesco from Italy. Recombinant adenovirus Ad.HCN2 was constructed and stored using Ad5 in this laboratory.METHODS: Pig BMSCs were isolated with combination of gradient centrifugation of Percoll and adherent treatment in vitro.Ad.HCN2 was transfected at multiplicity of infection=50. We also set non-transfection and transfected Ad.Null groups.MAIN OUTCOME MEASURES: Expression of HCN2 mRNA was detected with RT-PCR, and expression of HCN2 channel protein was examined with immunofluorescent staining. Electrophysiology of HCN2 channel protein was measured with whole-cell patch clamp.RESULTS: No amplified fragments were found in the non-transfection and transfected Ad.Null groups, but amplified fragments were determined at 250-500 bp following Ad.HCN2 amplification, which was the same as plasmid carrying HCN2 gene. Staining strength of cell nuclei following transfection was significantly weaken compared with cell membrane and plasma, which showed identical distribution as HCN2 protein. No HCN2 protein was detected in the non-transfection and transfected Ad.Null groups.Pacemaker current could be recorded with a whole-cell patch clamp. It was fully activated around -140 mV with an activation threshold of -60 mV, presenting voltage dependence. CsCI (4 mmol/L) reversibly blocked the inward currents. No pacemaker current was detected in the non-transfection and transfected Ad.Null groups.CONCLUSION: The HCN2 recombinant adenovirus carrier was transferred into serial subcultivation porcine bone marrow mesenchymal stem cells. HCN2 channel protein has been expressing. Pacemaker current could be recorded with a whole-cell patch clamp.

Objective:To prepare 2 composites using different proportions of hydroxyapatite and collagen and to assess their structural and biological properties, so as to pave a way for preparing tissue engineering chest wall scaffold.Methods: Two kinds of hydroxyapatite/collagen composites were prepared according to the weight ratios of 11 and 12; collagen sponge served as control. Then the structures of the 2 composites and the collagen sponge were observed under SEM. In vivo study was conducted to assess the biocompatibility and biodegradation of the composites by gross inspection and histological examination. Results: The collagen sponge had a 3-D network structure with fluey collagen fibers and poor mechanical strength, and its structure was damaged within 2 weeks after implantation and was completely absorbed 4 weeks later. The hydroxyapatite and collagen were well mixed in the composite with a hydroxyapatite to collagen ratio of 12; the composite had homogeneous 3-D porous structure (size of the pore being 100-400 m) and showed good biocompatibility: maintained its porous structure 4 weeks after implantation and was absorbed within 8 weeks. In composite with hydroxyapatite to collagen ratio of 11, the hydroxyapatite particles were separated from collagen fiber and conglomerated into masses, and the composite resulted in severe tissue reaction after implantation.Conclusion: When mixed with a reasonable proportion of hydroxyapatite, the collagen sponge has improved structure, biodegradable performance, and biocompatibility; the composite may be a novel scaffold for tissue engineering chest wall reconstruction.

Objective:To modify the pulsatile bioreactor we constructed previously for simulating the high-flow, high-pressure hemodynamics of heart valve in vivo, and to experimentally cultivate the tissue-engineered heart valves (TEHV) in the modified bioreactor. Methods: T-PLS system (NewheartBio Co., Ltd Korea) was used to generate pulsatile flow in the modified bioreactor and we designed a new air-exchange pathway to avoid contamination. The TEHV were made by seeding human bone mesenchymal stem cells (BMSCs) on de-cellularized porcine heart valve. After cultured under static condition for 4 d, the TEHVs were moved to the modified bioreactor and exposed to low-flow (0-600 ml/min) or high-flow(0-4 800 ml/min) pulsatile hydrodynamics for 7d, then the cells on TEHVs were evaluated. Results: After modification, the flow range expanded from (0-1 200) ml/min to (0-6 000) ml/min and the pressure range expanded from (0-40) mmHg to (0-180) mmHg. In culture experiments, 26.3% of the seeded cells remained under low-flow environment and cells were completely lost under the high-flow dynamics. Conclusion: The modified bioreactor can basically simulate the dynamics of heart valve in vivo and can be used in TEHV cultivation research. However, the current TEHV can not tolerate the high-flow pulsatile hydrodynamics.

BACKGROUND:Our preliminary study found that the monocusp valves made of ultramicropore expanded
polytetrafluoroethylene (ePTFE) revealed no significant thrombus, calcification, or degradation 20 weeks after implanted into the descending aorta and the left pulmonary artery in sheep, which verified the good property of ePTFE. However, the surface of ePTFE in the left pulmonary artery was covered with obvious neointima.
OBJECTIVE: To assess the biocompatibility of phosphorylcholine-coated ePTFE.
METHODS:ePTFE surface was modified by phosphorylcholine derivative. Then the changes of surface shape, tensile stress at yield and elasticity modulus, water contact angle, and protein absorption capacity of ePTFE after surface modification were observed. (1) Hemolytic test: the leaching solution of phosphorylcholine-coated ePTFE, leaching solution of uncoated ePTFE, normal saline, and distiled water were added to the diluted human blood, respectively. (2) Platelet count test: the phosphorylcholine-coated ePTFE, uncoated ePTFE, high density
polyethylene, and Zymosan A were added to the whole blood samples from healthy volunteers, respectively.
(3) Platelet activation test: the phosphorylcholine-coated ePTFE, uncoated ePTFE, γ-Globulins, and Zymosan A
were added to the whole blood samples from healthy volunteers, respectively.
RESULTS AND CONCLUSION: The mean micropore diameter of ePTFE was significantly decreased after
phosphorylcholine coating (P < 0.001). The hydrophilicity and the ability of suppressing protein adsorption were
significantly strengthened after phosphorylcholine coating (P < 0.001). Phosphorylcholine coating did not influence
ePTFE in biomechanical properties and hemolytic test. The platelet count test and platelet activation test demonstrated that phosphorylcholine coating significantly improved anti-thrombus function of ePTFE. So, phosphorylcholine coating can enhance anti-thrombus function, suppress protein adsorption, and improve biocompatibility of ePTFE.

Objective To summarize the experience with resurgery for recurrent valvular heart diseases.Methods From June 2004 to June 2015, 28 patients (15 males and 13 females) with ages ranging from 44 to 67 years (55.6±6.5 years) with recurrent heart valve disease underwent resurgery. The reasons for resurgery included perivalvular leakage (7 cases), bioprosthetic valve decline (6 cases in mitral valve and 3 in tricuspid valve), mechanical prostheses dysfunction (2cases), infective endocarditis after valve replacement (2 cases), restenosis of repaired native valve (1 case), and severe tricuspid insufficiency after left-side valve surgery (7 cases). Resurgery included mitral valve replacement in 18 patients and tricuspid valve replacement in 10. All the patients underwent third or fourth or even fifth cardiac surgery for valve replacement.Results There were 2 hospital deaths with a mortality of 7.1% (2/28). The main causes of early-stage deaths were low cardiac output syndrome. The main postoperative complications were respiratory failure in 3, low cardiac output syndrome in 2, reexploration for bleeding in 2 and serious infectious shock in 1. All the patients were found with the great improvement in heart function and the re-implanted prostheses worked well during follow-up.Conclusions Although resurgery for recurrent heart valve disease poses a continuing challenge to cardiac surgeon, it could be performed with the satisfactory results. The keys to a successful cardiac resurgery include appropriate operational timing, refined surgical technique and reasonable perioperative managements.

ObjectiveTo retrospectively analyze clinical data of patients who has left-side valvular disease combined with severe tricuspid regurgitation and evaluate the effect of our modified tricuspid annuloplasty with enforcement of artificial felt strip.Methods76 patients who had left-side valvular disease combined with severe tricuspid regurgitation received operations between Jan.2008 and Jun.2010.The average age of the patients was 53.5 years old (32 male and 44 female).Besides the severe tricuspid regurgitation, other combined cardiac impairments included mitral valvar disease (52 cases), aortic valvar disease(5 cases), double valvar disease(19 cases) and left atrial thrombosis(22 cases).6 patients had grade II cardiac function according to the NYHA criteria, while 47 and 23 were in grade III and IV, respectively.Other signs included cyanosis(5cases), jaundice(11 cases), neck vein engorgement(48 cases) , ascites(22 cases), hepatomegaly(41 cases) and pitting edema in the lower limbs(68 cases).The concomitant operative procedures included mitral valve replacement in 52 patients,aortic valve replacement in 5 patients, double valve replacement in 19 patients, removal of left atrial thrombus in 22 patients,left atrium folding in 21 patients and left atrium appendage suture in 68 patients.Left-sided valve disease were corrected first,TAP was performed on the beating heart after the heart had been defibrillated.The anteroseptal commissure was plicated first.A double-armed 3-0 pledgeted suture was taken through the base of the septal leaflet, 5-6 mm from the commissure, extending along the annulus, and out from the point in the anterior annulus 10-12 mm from the anteroseptal commissure.Both ends of the suture was tied until the two Teflon pledgets approximated each other near the commissure.Then a semicircular De Vega type of plicating with a 3-0 prolene was taken, starting just from the anterior annulus near the anteroposterior commissure, and extending clockwise to a point just cephalad to the posteroseptal commissure.The suture was tied with positioning a 27-29 mm valve siser across the tricuspid valve.At last, a 3-5 mm width felt strip was prepared and was sutured to the plicated posterior annulus region with interrupted mattress sutures of 2 to 3 2-0 prolene.A favorable result was considered when TR was not marked by saline injection.Echocardiography was routinely examined one week postoperatively and patients were followed up 6 month after discharge.ResultsThere is no death in all patients.The CVP diminished significantly from 16mmHg preoperatively to 8mmHg postoperatively (P = 0.0021).The systomic pulmonary pressure diminished from 59 mmHg preoperatively to 41 mmHg postoperatively (P = 0.038).Echo one week postoperative showed no tricuspid regurgitation in 56 patients and mild in 18 patients, while 2 had moderate tricuspid regurgitation.The diameter of right atrium diminished significantly postoperatively, too.The ejection fraction was improved even though there was not significant difference as compared with preoperative data.The cardiac function of all patients improved and the signs of right heart failure were alleviated or disappeared.Follow up 1 to 36 months showed no change of the regurgitation except for one become moderate from mild when discharged.No hepatic congestion or edema was observed in all patients.ConclusionThese new modifications make the technique more selective in the remodeling of the tricuspid annulus.It could achieve better coaptation of the anterior leaflet with the others, successful annular reduction, better maintenance of the contractile property of the tricuspid ring, better distribution of pursing force in the more dilated region.It could prevent the tear of the endocardium in the posteroseptal region in the long period of time postoperatively.