| Fibrin glue(FG)was first employed for local haemostasis in the early 20th century.Recently it was reported to be able to promote fistula healing and reduce closure time of postoperative enterocutaneous fistula(ECF).Derived from patients' plasmas,autologous platelet rich fibrin glue(PRFG)had high concentrations of fibrinogen(Fg)and thrombin(Th),and earned widespread applications in surgical fields.Autologous glue had advantages over commercial ones,since it eliminated the risks of infection transmission and allergy,as well as the high costs.Another advantage for autologous fibrin sealants identified in the present study is the presence of thrombocytes.The healing process was enhanced as blood platelets incorporated into the tissue adhesive glue with the release of growth factors upon activated by thrombin.Besides,homemade PRFG showed better biocompatible and controllable biodegradable effects.The PRFG sealing for low-output ECFs,however,has not been regularly used in clinical practice.In this study,we first constructed a series of sealants from autologous components and compared their functioning from composition,function,microscopy,storage,and antimicrobial aspects to Bioseal(?),a commonly used sealant.An in vivo evaluation of PRFG was also performed.In addition,the efficacy and safety of autologous PRFG in promoting closure of postoperative ECFs was investigated by a non-randomized prospective clinical study.Furthermore,risk factors affecting glue-assisted closure in patients who underwent glue application were determined by a retrospective analysis.Both univariate analysis and multivariate Cox proportional hazards model were utilized to determine the prognostic factors affecting closure.This thesis can be divided into the following three parts:PART ?:Preparation and evaluation of single-donor-derived,platelet-rich fibrin glueObjective:The present study sought to construct a series of sealants from autologous components and compare their functioning to Bioseal(?),a commonly used sealant.Methods:Characteristics of the platelet-rich plasma(PRP),platelet-poor plasma(PPP),Fg,and Th were determined and compared to commercial glue from composition,function,microscopy,storage,and antimicrobial aspects.Incisions were made on rats' back and were separately coated with PRFG with different concentrations of aminomethylbenzoic acid,commercial adhesives,and sham group.Histological analysis and immunohistochemistry were conducted at several time points.Results:Levels of complement and antibody did not significantly differ among PRFG,PRP,and PPP(P>0.05),while platelet and leukocyte counts in platelet-rich biomaterials were significantly higher than those in PPP,and commercial sealants(P<0.001).Mechanical values in two groups were not significantly different(P>0.05).A dense platelet surface and fibrin net structures could be observed in the autologous samples,whereas there were only sparse fibrin nets without cellular components in Bioseal(?).The reconstituted product was stable for up to 3 weeks at-20?.The bactericidal effects produced by PRFG and PRP were more pronounced than those by PPP in both qualitative and quantitative aspects.No inhibitory zones against three Gram-negative organisms were observed in the Bioseal(?).Acute inflammation existed within the first 6 days,and then gradually disappeared.Lowest concentration of antifibrinolytic agent in a 1:10 volume ratio with cryoprecipitate resulted in longer duration of sealants.The expression of CD31 in PRFG group was significantly higher than those in control group(Group G and H)at the 3rd day(P<0.05).Conclusion:Levels of platelet and leukocyte counts in PRFG were significantly higher than those in commercial sealants.Characterization of homemade and Bioseal fibrin sealants and their performance did not have significant difference in mechanical properties.Besides,in comparison of commercial products,PRFG had remarkable antimicrobial activity against Gram-negative bacteria.Single-unit PRFG had excellent biological compatibilities and was associated with upregulation of neovascularation.Addition of aminomethylbenzoic acid could prevent the degradation of FG.PART ?:Adjuvant Use of Autologous Platelet Rich Fibrin Glue in the Treatment of Fistulas:An Observational Cohort StudyObjective:Glue sealing has become a fistula occlusion alternative for its invasiveness and simplicity.The present study aimed to determine efficacy and safety of autologous PRFG in promoting closure of postoperative ECFs.Methods:This was a non-randomized prospective clinical study containing an initial cohort of 138 patients who had single tubular and low output ECFs.Besides standard of care,patients were assigned to either a PRFG treated group(n=75),or non-PRFG(control)group(n=63)upon enrollment.Moreover,a well-balanced sub-cohort of 56 patients(28 paired)was generated by propensity score(PS)matching from the initial cohort.Unadjusted and adjusted COX proportional hazard model was run to determine hazard ratios(HRs)of ECF closure on both cohorts.Results:Fistula closure rate within the first 28 days after enrollment was 57.1%in control group and 77.3%in PRFG group.Median fistula closure time was 23 days in control group arid 7 days in PRFG group.In all 138 patients enrolled in this study,PRFG-treated fistulas had 3.13(95%CI 1.82-5.36)times more likely to achieve closure,compared to non-PRFG patients.In PS-matched cohort with 28 paired fistula,HRs were 3.41(95%CI 1.91-6.07)for all fistula regardless of location,4.32(95%CI 1.68-11.1)for upper GI fistula,and 2.71(95%CI 1.21-6.06)for lower GI.Conclusion:Autologous PRFG appears safe and effective in patients with low output ECF.PRFG yields decreased closure times and increased closure rate,which may prove to be a useful non-invasive option in the management of digestive tract fistulas.PART ?:Risk factors for fistula closure in patients with enterocutaneous fistula receiving glue sealingObjective:ECF is the most challenging problem in surgical practice,and is hardly cured by spontaneous closure.Nowadays,glue-assisted closure earns great popularity in treatment of fistula,but data related to risk factors is limited.This study was designed to investigate the risk factors affecting outcomes in patients who underwent glue application.Methods:Eighty-two patients with 93 ECFs,who underwent autologous glue sealing from 2010 to 2012 in a referral center,were retrospectively analyzed.Their demographic data,clinical records,and fistula characteristics were collected.To determine the prognostic factors affecting closure,both univariate analysis and multivariate Cox proportional hazards model were utilized.Results:78.5%(73/93)fistulas achieved closure during the 14-day treatment period.After excluding 3 reopen fistulas,67 men and 12 women with a mean age of 47.3 ± 12.0 years were investigated.Univariate analysis demonstrated that patients with high levels of CRP,C:P ratio,and blood glucose,specific pathogen colonization,along with lower GI site,greater output volume,and shorter tract length,had a poor outcome(P<0.05).In a multivariate analysis,K.pneumoniae colonization inside the fistula tracts(Hazards ratio 0.191,95%CI 0.045-0.081,P=0.025)was a statistically significant risk factor for failure of fistula closure.Conclusions:The presence of K.pneumoniae in fistulous tracts was an independent risk factor of closure for patients receiving glue application.Therefore,debridement of the tracts should be considered as a more acceptable alternative for these high-risk patients. |
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