How does extracellular matrix-based growth factor delivery system promote osteogenesis? / 中国组织工程研究

BACKGROUND: The local application of growth factor provides a promising therapeutic strategy for the treatment of refractory bone defects. However, there are still many factors that limit the application of the local growth factor delivery system, for example, inability to accurately control the amount of growth factors released and the low biological activity of the released growth factors. OBJECTIVE: To summarize a variety of growth factor delivery systems containing extracellular matrix components and the latest research progress regarding their application in the treatment of bone defects. METHODS: The first authors searched PubMed, Web of Science, Medline, Wanfang and CNKI databases to retrieve articles published during 2007-2019 with the search terms “extracellular matrix, integrins, heparin, heparin, growth factor, controlled delivery system, bone defect” in English and Chinese, respectively. A total of 317 articles were initially retrieved, and 59 of them were included in the final analysis. RESULTS AND CONCLUSION: Extracellular matrix components can combine and regulate the activity of growth factors and improve their bioavailability. Therefore, improvement of growth factor delivery system can be achieved by integrating extracellular matrix components into the growth factor delivery system. Compared with the common growth factor delivery system, the extracellular matrix growth factor delivery system can obtain better growth factor binding effect, higher biological activity and utilization, and even better targeted release, thus producing better effects on promoting bone regeneration. Therefore, the extracellular matrix growth factor delivery system provides a better therapeutic strategy for local treatment of refractory bone defects.

Influence of PEG on heparin release of heparin-loading PCL/PEG vascular prosthesis membranes / 国际生物医学工程杂志

Objective To investigate the influence of polyethylene glycol (PEG) on heparin release of heparinloaded polycaprolactone/polyethylene glycol (PCL/PEG) membranes used in artificial vascular peosthesis.Methods Heparin-loaded PCL/PEG membrane samples with different PEG mass contents of 0,0.5％,10％ and 15％ were prepared by blending method and freeze-drying technology.The influence of PEG on heparin release was experimental studied in vitro.The influence of PEG on the structural characteristics of the samples were investigated by X-ray diffraction,Fourier transform infrared spectrum and differential scanning calorimeter.Results The addition of PEG reduced the heparin release resistance.The results showed that the average release rate of heparin in the first day and the release amount for 34 d were improved.Both these parameters increased with the increase of PEG mass content.The X-ray diffraction,Fourier transform infrared spectroscopy and differential scanning calorimetry showed that the crystallinity of PCL membrane was slightly enhanced by the addition of heparin,but the overall effect was not significant.In addition,the addition of heparin could promote the crystalline grain growth of PEG,and a common distribution of heparin and PEG in the matrix was observed.Conclusions The heparin release control can be achieved by adjusting the PEG mass content in heparin-loading PCL/PEG membranes prepared by blending method and freeze-drying technology.The proposed samples may have anticoagulant effect,which can be expected to be used as small-diameter artificial vascular prosthesis material.

Study on antithrombogenicity and surface heparinization of small intestinal submucosa / 中华创伤骨科杂志

Objective To study surface heparinization of small intestinal submucosa(SIS)and an- tithrombegenicity of beparinized SIS films with plasma initiation technique for the engineering vascular scaffolds. Methods The SIS films were grafted with heparin by hypothermia plasma initiation technique.The blood com- patibility of the modified SIS films was assessed by observing blood coagulation time in vitro and the long term pa- tency of hepafinized SIS vascular scaffolds directly under the circulation of blood.Results The hypothermia plasma initiation method could attach heparin onto the SIS surface,The water contact angle of SIS films modified with heparin was decreased while the surface free energy and hydrophilicity increased.The prothrombin time(PT),ac- tivated partial thromboplastin time(APTT)and thrombin clotting Time(TT)of the SIS films modified with heparin were prolonged obviously.Small caliber engineering vascular scaffold made of heparinized SIS films kept the patency for six weeks.Conclusion Heparin can be attached to SIS films by hypothermia plasma initiation technique.The modified surfaces provide good and persistent antithrombogenicity,and possess potent blood compatibility,

Adequacy of Individualized Heparinization during Hemodialysis / 대한신장학회잡지

BACKGROUND: Most chronic hemodialysis units select heparin doses on an empirical basis. Too little heparin causes clotting in the extracorporeal circuit and too much heparin may lead to excessive bleeding. We conducted a prospective, randomized, repeated cross over study to evaluate the effect of two different heparin regimens. The empirical standard dose regimen (empirical heparinization, EH) was used for all patients, and the individualized dose regimen (individualized heparinization, IH) determined by measuring the activated clotting time (ACT) was performed for more adequate heparinization during hemodialysis. METHODS: Twenty-four outpatients with systemic heparinization who had been on hemodialysis for more than 3 months were enrolled. In both METHODS, anticoagulation was achieved with a loading dose and a continuous infusion of heparin. Each regimens were prescribed alternately, and repeated after 2 weeks later. The study evaluated pre-post dialytic Hgb, Hct, Platelet and predialytic albumin, heparin loading dose and infusion rate, ACT, total blood compartment volume (TBCV), visible blood clots, bleeding, pre-post dialytic and next predialytic BUN, predialytic Cr, URR, Kt/Vurea. RESULTS: Twenty-two patients were analyzed in this study. Pre-post dialytic Hgb, Hct, Platelet and predialytic albumin, heparin loading dose were not significantly different between two methods. But heparin infusion rate were significantly increased in individualized heparinization than in empirical heparinization. Activated clotting times were prolonged and maintained adequately in individualized heparinization during hemodialysis. The loss of TBCV and visible blood clots were significantly decreased in individualized heparinization than in empirical heparinization. There was no bleeding complication in two methods. Pre-post and next predialytic BUN, predialytic Cr, URR, Kt/Vurea were not significantly different between two methods.0.CONCIUSION: We concluded that the individualized heparinization can maintain adequate anticoagulation than the empirical heparinization without any other problems and compromising the delivery dose of dialysis.

Adequacy of Individualized Heparinization during Hemodialysis / 대한신장학회잡지

BACKGROUND: Most chronic hemodialysis units select heparin doses on an empirical basis. Too little heparin causes clotting in the extracorporeal circuit and too much heparin may lead to excessive bleeding. We conducted a prospective, randomized, repeated cross over study to evaluate the effect of two different heparin regimens. The empirical standard dose regimen (empirical heparinization, EH) was used for all patients, and the individualized dose regimen (individualized heparinization, IH) determined by measuring the activated clotting time (ACT) was performed for more adequate heparinization during hemodialysis. METHODS: Twenty-four outpatients with systemic heparinization who had been on hemodialysis for more than 3 months were enrolled. In both METHODS, anticoagulation was achieved with a loading dose and a continuous infusion of heparin. Each regimens were prescribed alternately, and repeated after 2 weeks later. The study evaluated pre-post dialytic Hgb, Hct, Platelet and predialytic albumin, heparin loading dose and infusion rate, ACT, total blood compartment volume (TBCV), visible blood clots, bleeding, pre-post dialytic and next predialytic BUN, predialytic Cr, URR, Kt/Vurea. RESULTS: Twenty-two patients were analyzed in this study. Pre-post dialytic Hgb, Hct, Platelet and predialytic albumin, heparin loading dose were not significantly different between two methods. But heparin infusion rate were significantly increased in individualized heparinization than in empirical heparinization. Activated clotting times were prolonged and maintained adequately in individualized heparinization during hemodialysis. The loss of TBCV and visible blood clots were significantly decreased in individualized heparinization than in empirical heparinization. There was no bleeding complication in two methods. Pre-post and next predialytic BUN, predialytic Cr, URR, Kt/Vurea were not significantly different between two methods.0.CONCIUSION: We concluded that the individualized heparinization can maintain adequate anticoagulation than the empirical heparinization without any other problems and compromising the delivery dose of dialysis.

A Case of Pulmonary Embolism After Cesarean Delivery / 대한산부인과학회잡지

Pulmonary Embolism, one of the causes of maternal death, is a life threatening disease that needs early and accurate diagnosis. We have exprerienced a case of a fatal pulmonary embolism which was diagnosed by lung perfusion scan on the postoperative 1 day after cesarean delivery and was managed with heparin therapy. We present this case with a brief review of literatures.