Commercial fibrin sealants in surgical care

Successful surgical closure and continence rate of obstetric fistula in Africa: systematic review and meta-analysis

Background

A female genital fistula is an abnormal connection between a woman's reproductive tract and her urinary tract or rectum. While numerous studies have aimed to determine the success rate of obstetric fistula closure in different health settings, there remains a significant scarcity of data on closure success rates and incontinence rates for various types of fistulas at the regional and sub-regional levels. The success rate reflects the continent's healthcare setup in regard to the World Health Organization standards. Thus, this study aims to determine the success of surgical closure and the continence rate of obstetric fistula in Africa.

Methods

This systematic review and meta-analysis review includes studies conducted up to February 2023. Search engines like EMBBASE, Medline, Google, PubMed, Google Scholar, African Journals Online, and ScienceDirect databases were utilized to find articles. The Joanna Briggs Institute critical evaluation checklist was used to evaluate the quality of our review, which was conducted in accordance with PRISMA criteria. Heterogeneity was indicated by a p-value for I2 statistics of less than 0.05. Publication bias was assessed using the Egger regression asymmetry test. Data were entered into Microsoft Excel and analyzed using STATA 16.

Result

This review includes 85 studies. A total of 24 countries from East, West, Central, North, and Southern African sub-regions were included. The overall pooled estimated rate of successful obstetric fistula closure is 86.15 (95% CI: 83.88-88.42). Moreover, the pooled estimated rate of successfully closed vesico-vaginal fistulas but with ongoing or residual incontinence (wet) was revealed as 13.41% (95% CI: 11.15-15.68). The pooled estimated rate of successfully closed rectovaginal fistulas and combined VVF and RVF are 91.06% (95% CI: 86.08-96.03) and 62.21% (95% CI: 48.94-75.49), respectively.

Conclusions

The rate of successful obstetric fistula closure in Africa is 86.15, which is higher than the WHO target. However, the surgical closure rate of a combined VVF and RVF is 62.2%, which is significantly lower than the WHO target.

A comparative high-resolution physicochemical analysis of commercially available fibrin sealants: Impact of sealant osmolality on biological performance

Fibrin sealants are well-established components of the surgical toolbox, especially in procedures that harbor a high risk of perioperative bleeding. Their widespread use as hemostats, sealants or tissue-adhesives in various surgical settings has shown that the choice of the appropriate sealant system affects the clinical outcome. While many studies have compared the hemostatic efficiency of fibrin sealants to that of other natural or synthetic sealants, there is still limited data on how subtle differences in fibrin sealant formulations relate to their biological performance. Here, we performed an in-depth physicochemical and biological characterization of the two most commonly used fibrin sealants in the US and Europe: TISSEEL™ ("FS") and VISTASEAL™/VERASEAL™ ("FS+Osm"). Our chemical analyses demonstrated differences between the two sealants, with lower fibrinogen concentrations and supraphysiological osmolality in the FS+Osm formulation. Rheological testing revealed FS clots have greater clot stiffness, which strongly correlated with network density. Ultrastructural analysis by scanning electron microscopy revealed differences between FS and FS+Osm fibrin networks, the latter characterized by a largely amorphous hydrogel structure in contrast to the physiological fibrillar network of FS. Cytocompatibility experiments with human fibroblasts seeded on FS and FS+Osm fibrin networks, or cultured in presence of sealant extracts, revealed that FS+Osm induced apoptosis, which was not observed with FS. Although differential sealant osmolality and amounts of fibrinogen, as well as the presence of Factor XIII or additives such as antifibrinolytics, may explain the mechanical and structural differences observed between the two fibrin sealants, none of these substances are known to cause apoptosis at the respective concentrations in the sealant formulation. We thus conclude that hyper osmolality in the FS+Osm formulation is the primary trigger of apoptosis-a mechanism that should be evaluated in more detail, as it may affect the cellular wound healing response in situ.

Autologous Platelet-Rich Plasma Injection and Platelet-Rich Fibrin Glue Insertion for the Treatment of Extensive Supralevator Anorectal Fistula: A Case Report

Supralevator fistula stays a challenge in general surgery. We present a case with supralevator anorectal fistula and subsequent retroperitoneal necrotizing fasciitis in which autologous platelet-rich plasma and platelet-rich fibrin glue were used for fistula closure. A 59-year-old man was admitted with pelvic pain and fever. Abdominopelvic sonography and CT scan reported a deep horseshoe-shaped anorectal abscess with extension to the pelvic floor, supralevator, psoas, retroperitoneal muscles, and kidneys. He was managed with antibiotics, abscess drainage, repeated radical surgical debridement, and necrosectomy. After 30 days, he was discharged, but he returned to the office with the complaint of purulent discharge from the hypogastric region and a diagnosis of fistula formation. Platelet-rich plasma was injected around the fistula into the tissue, and platelet-rich fibrin glue was introduced to the fistula tract. At the 11-month follow-up, the patient did not have voiding dysfunction, constipation, diarrhea, or fistula tract infection. Autologous platelet-rich plasma injection and platelet-rich fibrin glue insertion suggest a secure and effective approach for treating supralevator anorectal fistula.

Biologic adjuvant urethral coverings for single-stage primary hypospadias repairs: A systematic review and pooled proportional meta-analysis of postoperative urethrocutaneous fistulas

BACKGROUND

The use of barrier layers between the neourethra and skin is associated with lower rates of post-operative urethrocutaneous fistula (UCF) following hypospadias surgery. Recent studies have evaluated the ability of biologic adjuvant urethral coverings (BAUCs) - namely acellular matrix (AM), tissue adhesives (TAs), and autologous platelet-rich plasma or fibrin (PRP/PRF) - to prevent wound complications following hypospadias surgery. In general, however, these studies are small and conducted at single institutions.

OBJECTIVE

To assess the effect of BAUCs on the rate of UCF following single-stage primary hypospadias repair.

METHODS

We conducted a systematic review of studies reporting the rate of postoperative UCF in pediatric patients undergoing single-stage, primary hypospadias repairs using either AM, TA, or PRP/PRF as a layer interposed between the neourethra and skin. We then performed a pooled proportional meta-analysis of post-operative UCF. Patients within each study who underwent comparable surgery but did not receive a BAUC were used as controls.

RESULTS

10 studies were included in our review. The meta-analysis included 280 patients from 7 studies who underwent hypospadias repairs with BAUCs. The pooled incidence of UCF was 10% (95% CI 6-14%). Mean follow-up ranged 5-23.5 months in the 5/7 studies reporting specific durations, and ≥6 month and 14-30 months, respectively, in the other two studies. Patients in whom a BAUC was used had significantly lower odds of UCF than control patients (OR 0.39, 95% CI 0.24-0.64, p = 0.0002). In subgroup analyses, significant superiority held for AM and TA; proximal or penoscrotal cases; transverse preputial island flap (TPIF) technique; when both cases and controls had local flaps; and when neither cases nor controls had flaps.

DISCUSSION

The use of BAUCs was associated with decreased rates of post-operative UCF in single-stage primary hypospadias repairs and may be most beneficial in more severe cases and when used in addition to local flaps or when using a flap is not possible. In 2/3 studies of PRP/PRF and 2/4 studies of tubularized incised plate (TIP) technique, dartos flaps were used in controls but not BAUC patients, which may explain the lack of benefit demonstrated for these subgroups. This meta-analysis is limited by the quality of evidence in the included studies, which are not uniformly randomized. Furthermore, the follow-up durations and methods for assessing complications are not standardized between included studies.

CONCLUSION

The meta-analysis herein suggests that using BAUCs may reduce UCF rates following hypospadias surgery. Rigorous prospective evaluation is needed to validate this benefit.

Evaluation of the long-term results of vascular anastomosis using polyurethane adhesive and shape-memory stent in the rat carotid artery model

INTRODUCTION

In free flaps, 5%-10% of complications are related to failure of sutured vascular anastomoses. Adhesive-based microvascular anastomoses are potential alternatives but are associated with failure rates of 70% in research studies. VIVO is a new adhesive with slow biodegradation within 6 months that has shown a 100% patency rate in research studies over 2 h observation time but long-term patency has not been evaluated. The authors hypothesize that VIVO will enable a reliable microvascular procedure comparable to sutured anastomoses over a 28-day period.

MATERIALS AND METHODS

The right common carotid artery of 60 male Sprague Dawley rats, ~450 g, were used for microvascular end-to-end anastomosis. VIVO was applied with reduced sutures with a temporary catheter in one group and in the other with a custom-shaped memory stent. Anastomoses with eight interrupted sutures served as control. All groups were n = 20. Anastomosis time and bleeding were recorded for each procedure. Doppler flowmetry was performed 20 min, 1, 10, and 28 days postoperatively. Postmortem toluidine staining was used for semi-quantitative analysis of stenosis, thrombosis, necrosis, and aneurysm formation by histologic evaluation.

RESULTS

No occlusion was detected 20 min and 1 day postoperative, and after 28 days of observation in all anastomoses. The anastomosis time of the VIVO with catheter group was about 32% significantly faster than the VIVO with stent group. In the VIVO group with stent, the bleeding time was ~80% shorter than in the control group with 2.1 ± 0.3 and VIVO with catheter 2.0 ± 0.5 (p ≤ .001 each). Minor and nonsignificant stent-associated thrombus formation and stent-typical intraluminal stenosis were detected exclusively in the VIVO with stent group.

CONCLUSION

Within the limitations of a rat study, the use of VIVO in anastomosis showed promising results. VIVO with catheter was found to be advantageous.

Current Concepts on Tissue Adhesive Use for Meniscal Repair-We Are Not There Yet: A Systematic Review of the Literature

BACKGROUND

Tissue adhesives (TAs) represent a promising alternative or augmentation method to conventional tissue repair techniques. In sports medicine, TA use has been suggested and implemented in the treatment of meniscal tears. The aim of this review was to present and discuss the current evidence and base of knowledge regarding the clinical usage of TAs for meniscal repair.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic literature search was performed using the PubMed, Embase, and Cochrane Library databases for studies reporting on clinical outcomes of TA usage for meniscal repair in humans in the English language published before January 2020.

RESULTS

Ten studies were eligible for review and included 352 meniscal repairs: 94 (27%) were TA-based repairs and 258 (73%) were combined suture and TA repairs. Concomitant anterior cruciate ligament reconstruction was performed in 224 repairs (64%). All included studies utilized fibrin-based TA. Of the 10 studies, 9 were evidence level 4 (case series), and 8 reported on a cohort of ≤40 meniscal repairs. Rates of meniscal healing were evaluated in 9 of 10 studies, with repair failure seen in 39 repairs (11%).

CONCLUSION

The use of TAs, specifically fibrin-based TAs, for meniscal repair shows good results as either an augmentation or primary repair of various configurations of meniscal tears. However, this review reveals an absence of comparative high-quality evidence supporting the routine use of TAs for meniscal repair and emphasizes the lack of an ideal TA designed for that purpose. Further high-quality research, basic science and clinical, will facilitate the development of new materials and enable testing their suitability for use in meniscal repair.

Fibrin sealant versus sutures in periodontal surgery: A systematic review

Background

The aim of this systematic review was to assess the effectiveness of fibrin sealant compared to sutures in periodontal surgery.

Methods

Five electronic databases (PubMed, Scopus, EBSCO, Cochrane and Web of Science) were screened from initiation to January 2021 for randomized controlled trials (RCTs) comparing fibrin sealant to sutures in periodontal surgery using this search equation: (Periodont* OR Periodontitis) AND ("fibrin tissue adhesive" OR "fibrin glue" OR "fibrin sealant" OR "fibrin sealant system" OR "fibrin adhesive system" OR "fibrin fibronectin sealant system"). Quality assessment of the included studies was performed using the revised tool to assess risk of bias in randomized trials (RoB 2). The level of evidence was evaluated using the GRADE tool.

Results

A total of 240 publications were found as search results in the screened databases. Four RCTs were included in this systematic review based on predetermined inclusion criteria. The trials were published between 1987 and 2014. All the RCTs compared fibrin sealant to sutures in periodontal surgery. The sample size included 101 patients. The overall risk of bias in this systematic review was at high risk in 75% of the studies, while 25% of the studies raised some concerns. The level of evidence evaluated using GRADE tool was very low.

Discussion

The current systematic review indicates a low level of evidence of the use of fibrin sealant as an alternative to sutures in periodontal practice. More interventional and multicentric studies should be conducted to support and confirm the results of the included studies.

A Systematic Review of Fibrin Glue as an Ideal Treatment for the Pilonidal Disease

Pilonidal sinus is an acquired condition caused by irritation to the hair follicles at the natal cleft, presenting with an abscess or chronic infection. It is prevalent in young adults affecting their productive lifestyle with morbidities. There are varieties of treatment options; however, there is no consensus yet for the ideal procedure. Less invasive procedures have evolved to replace the traditional surgical techniques, which cannot significantly reduce the risks of recurrence and wound complications despite extensive surgeries. We aimed to assess the effect of fibrin glue as a primary treatment after cleaning the sinus in pilonidal sinus disease. We searched for articles from PubMed®, Ovid MEDLINE®, Ovid EMBASE®, and Cochrane CENTRAL. Six studies that included 336 patients in total were analyzed. Fibrin glue treatment in these studies reported a quicker return to normal activities postoperatively, a low rate of infection, and an acceptable rate of recurrence. Thus, fibrin glue seems beneficial in the management of pilonidal disease. However, further high-quality studies are essential to support and confirm this evidence. Future research should also evaluate its cost and implications in the ambulatory service.

The Impact of Fibrin Sealant Volume on Skin Graft Contraction in a Full-Thickness Skin Graft Model

BACKGROUND

Fibrin sealant has been used for skin grafting in anatomically difficult facial areas. Although biodegradable, an excess of fibrin sealant may inhibit skin graft healing by inhibiting diffusion at the graft-recipient bed interface. The impact of fibrin sealant volume on graft healing was examined in a rat full-thickness skin graft model.

METHODS

Seventy-two full-thickness 2.5 × 2.5-cm skin grafts were used on the dorsum of male Sprague-Dawley rats. The grafts were treated with three different volumes of fibrin sealant placed onto the recipient bed: 0.0 mL or normal saline (group 1), 0.1 mL (group 2), and 0.4 mL (group 3). Graft healing and complications were assessed using digital photographs and necropsies on postoperative days 3, 7, and 21.

RESULTS

Group 3 showed the greatest graft contraction on days 3 and 21, while group 2 showed the least contraction on all 3 postoperative days (P = 0.002, 0.004, and <0.001, respectively). Histopathologic analysis showed inflammatory foreign body reactions in group 3 on days 3 and 7, and less vascular density on day 21 (P = 0.003). Group 1 showed the highest incidence of hematoma (P = 0.004).

CONCLUSION

An excess volume of fibrin sealant may produce pathologic wound contraction in skin grafting because a skin graft lacks a vascular pedicle and is highly dependent on diffusion from the host environment. Before using fibrin sealant for skin grafting in facial areas where the aesthetic outcome is important, the appropriate volume to use can be determined.

Pressure-Sensitive Tissue Adhesion and Biodegradation of Viscoelastic Polymer Blends

Viscoelastic blends of biodegradable polyesters with low and high molecular weight distributions have remarkably strong adhesion (significantly greater than 1 N/cm2) to soft, wet tissue. Those that transition from viscous flow to elastic, solidlike behavior at approximately 1 Hz demonstrate pressure-sensitivity yet also have sufficient elasticity for durable bonding to soft, wet tissue. The pressure-sensitive tissue adhesive (PSTA) blends produce increasingly stronger pull-apart adhesion in response to compressive pressure application, from 10 to 300 s. By incorporating a stiffer high molecular weight component, the PSTA exhibits dramatically improved burst pressure (greater than 100 kPa) when used as a tissue sealant. The PSTA's biodegradation mechanism can be switched from erosion (occurring primarily over the first 10 days) to bulk chemical degradation (and minimal erosion) depending on the chemistry of the high molecular weight component. Interestingly, fibrosis toward the PSTA is reduced when fast-occurring erosion is the dominant biodegradation mechanism.

Fibrin Glue Used Successfully in Peritoneal Dialysis Catheter Leakage in Children

Background

Acute renal failure in infants and small children is generally treated with peritoneal dialysis (PD). Dialysis has to be started immediately after catheter implantation. Early dialysate leakage can complicate the effectiveness of dialysis. Fibrin glue applied to the external part of the tunnel may stop dialysate leakage and eliminate the need for surgical intervention. The use of fibrin glue in the treatment of PD catheter leakage in children was studied.

Methods

Fibrin glue was used in 8 children (age 0.8 – 57 months) on PD in whom dialysate leakage was seen during the first 24 to 48 hours after catheter insertion. The dialysis volume initially administered was 20 mL/kg body weight. Fibrin glue (1 mL) was applied to the external part of the subcutaneous catheter tunnel through the exit site, as close to the cuff as possible. The occurrence of dialysate leakage and complications such as exit-site or tunnel infection and peritonitis were evaluated.

Results

Nine single-cuff straight Tenckhoff catheters were implanted in 8 children. In 5 cases, no subcutaneous tunnel was created. One child had catheter replacement due to obstruction of the catheter; on both occasions, catheter leakage was seen and treated with fibrin glue. In all 8 patients, no relapse of dialysate leakage was seen after application of the fibrin glue. During the time of PD, exit-site infections, tunnel infections, and peritonitis did not occur.

Conclusion

Fibrin glue is a successful, simple, and safe substance for the treatment of peritoneal dialysate leakage in infants and small children with acute renal failure treated with PD.

Fibrin biopolymer as scaffold candidate to treat bone defects in rats

BACKGROUND

Bone tissue repair remains a challenge in tissue engineering. Currently, new materials are being applied and often integrated with live cells and biological scaffolds. The fibrin biopolymer (FBP) proposed in this study has hemostatic, sealant, adhesive, scaffolding and drug-delivery properties. The regenerative potential of an association of FBP, biphasic calcium phosphate (BCP) and mesenchymal stem cells (MSCs) was evaluated in defects of rat femurs.

METHODS

Adult male Wistar rats were submitted to a 5-mm defect in the femur. This was filled with the following materials and/or associations: BPC; FBP and BCP; FBP and MSCs; and BCP, FBP and MSCs. Bone defect without filling was defined as the control group. Thirty and sixty days after the procedure, animals were euthanatized and subjected to computed tomography, scanning electron microscopy and qualitative and quantitative histological analysis.

RESULTS

It was shown that FBP is a suitable scaffold for bone defects due to the formation of a stable clot that facilitates the handling and optimizes the surgical procedures, allowing also cell adhesion and proliferation. The association between the materials was biocompatible. Progressive deposition of bone matrix was higher in the group treated with FBP and MSCs. Differentiation of mesenchymal stem cells into osteogenic lineage was not necessary to stimulate bone formation.

CONCLUSIONS

FBP proved to be an excellent scaffold candidate for bone repair therapies due to application ease and biocompatibility with synthetic calcium-based materials. The satisfactory results obtained by the association of FBP with MSCs may provide a more effective and less costly new approach for bone tissue engineering.

Wound healing effect of regenerated oxidized cellulose versus fibrin sealant patch: An in vivo study

Background

Topical hemostatic agents are used when ligation, electrocauterization, or other conventional hemostatic methods are impractical. Because a hemostatic agent is a foreign body, it can cause foreign body reactions, inflammation, and infections that can interfere with the wound healing process. Therefore, we should select hemostatic agents after considering their effects on wound healing. Here, we compared the effects of hemostatic agents on wound healing in a rectus abdominis muscle defect in rats.

Methods

Twelve Sprague Dawley rats were subjected to creation of a 6 × 6 mm defect in the rectus abdominis muscle and divided into four groups: control group; group A, Tachosil fibrin sealant patch; group B, Surgicel Fibrillar oxidized regenerated cellulose; and group C, Surgicel Snow oxidized regenerated cellulose. For the histologic analysis, biopsies were performed on the 3rd, 7th, and 27th days.

Results

The foreign body reaction was the weakest in group A and most significant in group C. The inflammatory cell infiltration was the weakest in group A and similar in groups B and C. Muscle regeneration differed among periods. The rats in group A were the most active initially, while those in group C showed prolonged activity.

Conclusion

Tachosil and Surgicel administration increased inflammation via foreign body reactions, but the overall wound healing process was not significantly affected. The increased inflammation in the Surgicel groups was due to a low pH. We recommend using Tachosil, because it results in less intense foreign body reactions than Surgicel and faster wound healing due to the fibrin action.

Fibrin-thrombin sealant does not reduce lymphocele formation in patients with inguinofemoral lymphadenectomy for vulvar cancer

Purpose: Inguinofemoral lymphadenectomy (IFLD) is associated with very high morbidity. Fibrin sealant patches are used in various surgical procedures to prevent hematomas and lymphoceles. Here, we report a single-institution experience of fibrin sealants after IFLD in vulvar cancer and give an overview of the current literature.

Patients and methods: We retrospectively analyzed outcome data on vulvar cancer patients who underwent bilateral IFLD between November 2014 and June 2016 at the University Hospital Basel. A fibrin sealant patch (Tachosil^®) was placed in one groin only. Postsurgical fluid collection and complications were compared between both groins; time courses of lymphocele formation were analyzed using a linear mixed-effects regression model.

Results: Postsurgical outcome of 11 consecutive patients with bilateral IFLD for vulvar cancer was assessed for a median follow-up of 32 days (range 12–77). Significantly larger lymphoceles were detected over time in the groin with the fibrin sealant patch (median 20 mL vs 5 mL without patch, p=0.002), and more punctures for symptomatic lymphocele were required on this side. The infection rate did not differ between sides.

Conclusion: Fibrin sealant patches should not routinely be used for prevention of lymphoceles after IFLD for vulvar cancer. They do not seem to reduce lymph collection, the need for puncture or the infection risk after lymphadenectomy in our experience and according to a general literature review.

Systematic review of fibrin glue in burn wound reconstruction

Background

In the reconstruction of burns using split-skin grafts (SSGs), fibrin glue can be used to improve graft take and reduce haematoma formation, although the efficacy and cost-effectiveness are unknown. This systematic review evaluated outcomes of fibrin glue compared with conventional SSG attachment techniques. Outcomes of interest included SSG take, haematoma formation, patient satisfaction and cost-effectiveness.

Methods

This PROSPERO-registered review was performed in accordance with the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA statement. Embase, PubMed, Cochrane and ClinicalTrial.gov databases were searched systematically. Observational and experimental studies comparing fibrin glue with other methods of SSG attachment in burn wounds were included. Risk of bias was assessed using the Cochrane risk-of-bias and Risk of Bias In Non-Randomized Studies – of Intervention tools. The quality of the evidence was assessed using the GRADE tool.

Results

Two RCTs and four observational studies were included. Graft take at day 5 was not significantly different between groups (3 studies, 183 individuals). Fibrin glue significantly reduced the risk of postoperative haematoma in two studies and reduced patient-reported pain in two studies, with suggested cost savings in four studies. All studies were at risk of methodological bias and the quality of the evidence was universally very low.

Conclusion

As the evidence is sparse, the quality very low and the risk of bias significant both within and across studies, it is not possible to make any recommendations regarding the use of fibrin glue in burn wounds.

Biofabricating Functional Soft Matter Using Protein Engineering to Enable Enzymatic Assembly

Biology often provides the inspiration for functional soft matter, but biology can do more: it can provide the raw materials and mechanisms for hierarchical assembly. Biology uses polymers to perform various functions, and biologically derived polymers can serve as sustainable, self-assembling, and high-performance materials platforms for life-science applications. Biology employs enzymes for site-specific reactions that are used to both disassemble and assemble biopolymers both to and from component parts. By exploiting protein engineering methodologies, proteins can be modified to make them more susceptible to biology's native enzymatic activities. They can be engineered with fusion tags that provide (short sequences of amino acids at the C- and/or N- termini) that provide the accessible residues for the assembling enzymes to recognize and react with. This "biobased" fabrication not only allows biology's nanoscale components (i.e., proteins) to be engineered, but also provides the means to organize these components into the hierarchical structures that are prevalent in life.

Fibrin-based delivery strategies for acute and chronic wound healing

Fibrin, a natural hydrogel, is the end product of the physiological blood coagulation cascade and naturally involved in wound healing. Beyond its role in hemostasis, it acts as a local reservoir for growth factors and as a provisional matrix for invading cells that drive the regenerative process. Its unique intrinsic features do not only promote wound healing directly via modulation of cell behavior but it can also be fine-tuned to evolve into a delivery system for sustained release of therapeutic biomolecules, cells and gene vectors. To further augment tissue regeneration potential, current strategies exploit and modify the chemical and physical characteristics of fibrin to employ combined incorporation of several factors and their timed release. In this work we show advanced therapeutic approaches employing fibrin matrices in wound healing and cover the many possibilities fibrin offers to the field of regenerative medicine.

Analysis of the hemostatic potential of modern topical sealants on arterial and venous anastomoses: an experimental porcine study

One of the widely accepted adjunctive agents in the variety of surgical modalities are sealants. Our study aim was to compare four commonly used modern sealants in a standardized experimental setting to assess their feasibility, and hemostatic efficacy in vascular anastomosis. Forty landrace pigs (weight: 24.7 ± 3.8 kg) were randomized into the control (n = 8) and four sealant groups; TachoSil® (n = 8), Tissucol Duo® (n = 8), Coseal® (n = 8), and FloSeal® (n = 8). After doing a portal vein end-to-end anastomosis as well as stitches of aortic incision, the sealants were applied on anastomotic site. The control group was left intact. In portal vein anastomosis, the sealants led to a complete hemostasis significantly better than control group. The mean of blood loss was also significantly reduced. In successful subgroups, there was a difference in the mean-time to reach complete hemostasis ranging from 15 s in Coseal® to 76 s in FloSeal® group (p  < 0.05). In aortotomy experiments, except Tissucol Due®, which had insufficient hemostasis, other sealants led to a complete hemostasis. The mean blood loss was significantly reduced in sealants groups as well. The four sealants are effective in reducing the suture-hole bleeding in portal vein anastomosis. However, the hemostatic potential is heterogeneous among sealants. This means that "one-size-fits-all" approach is not appropriate for application of sealants in diversity of vascular surgery and it should be based on the type and the severity of injury and the structure of tissue. Comparison of hemostasis efficacy of four modern sealants (TachoSil®, Tissucol Duo®, Coseal®, and FloSeal®) in vascular anastomosis in porcine model. The figures below show the total blood loss (g) in the control and sealant groups after aortotomy (left) and portal vein anastomosis (right). The mean of blood loss decreased significantly by the usage of sealants in both experiment groups as compared to control group (*: p < 0.05; sealant groups vs. control group). 1. The right column shows the mean of blood loss (g) in all experiments in each group. 2. The middle column presents the subgroup with unsuccessful hemostasis at the end of observation time (Tmax = 20 sec. for aortotmy and 300 sec. for portal vein anastomosis). 3. The left column shows mean of total blood loss in subgroups with successful hemostasis during observation time (20 sec for aortotomy and 300 sec for portal vein).

Percutaneous intratumoral injection of gemcitabine plus cisplatin mixed with fibrin glue for advanced pancreatic carcinoma: Case Report

RATIONALE

The aim of this study was to determine the effectiveness of intratumoral injection of chemotherapeutics in improving the quality of life and survival of patients with pancreatic carcinoma.

PATIENT CONCERNS

We present a case series of 5 patients with unresectable pancreatic adenocarcinoma.

DIAGNOSES

Patients diagnosed with unresectable poorly differentiated pancreatic ductal adenocarcinoma by intraoperative frozen biopsyor percutaneous biopsy.

INTERVENTIONS

Five patients with unresectable pancreatic adenocarcinoma received a computed tomography-guided percutaneous intratumoral injection of gemcitabine plus cisplatin mixed with fibrin glue.

OUTCOMES

Mean overall survival was 16.2 ± 3.7 months. Local control rates were 100% and 80% at postoperative 3 and 6 months, respectively. Mean Visual Analogue Scale pain score decreased from 7.2 ± .84 preoperatively to 2 ± 1.22 at postoperative 4 weeks. There were no complications associated with the procedure.

LESSONS

Percutaneous intratumoral injection of gemcitabine plus cisplatin mixed with fibrin glue for advanced pancreatic may be safe and effective.

Novel synthetic adhesive as an effective alternative to Fibrin based adhesives

AIM

To compare a novel, fully synthetic, polyurethane based glue (MAR-1) to fibrin sealant in a partial liver resection rat model.

METHODS

After 50% resection of the lateral left liver lobe in male Wistar rats (n = 7/group/time point), MAR-1, Fibrin or NaCl was applied. After 14, 21 and 90 postoperative days, sealant degradation, intra-abdominal adhesions were scored, and histological examination of liver tissue was performed.

RESULTS

(Mean ± SEM) (MAR-1 vs Fibrin vs NaCl). Bleeding mass was significantly higher in NaCl (3.36 ± 0.51 g) compared to MAR-1 (1.44 ± 0.40 g) and Fibrin (1.16 ± 0.32 g). At 14 and 90 d, bleeding time was significantly lower in MAR-1 (6.00 ± 0.9 s; 13.57 ± 3.22 s) and Fibrin (3.00 ± 0.44 s; 22.2 ± 9.75 s) compared to NaCl (158.16 ± 11.36 s; 127.5 ± 23.3 s). ALT levels were significantly higher in MAR-1 (27.66 ± 1 U/L) compared to Fibrin (24.16 ± 0.98 U/L) and NaCl (23.85 ± 0.80 U/L). Intrabdominal adhesions were significantly lower in MAR-1 (11.22% ± 5.5%) compared to NaCl (58.57% ± 11.83%). Degradation of the glue was observed and MAR-1 showed almost no traces of glue in the abdominal cavity as compared to the Fibrin (10% ± 5% 14 d; 7% ± 3% 21 d). Survival showed no significant differences between the groups.

CONCLUSION

Compared to Fibrin, MAR-1 showed similar hemostatic properties, no adverse effects, and is biocompatible. Further studies on adhesion strength and biodegradability of synthetic sealants are warranted.

In Vitro and In Vivo Characterization of Biodegradable Reactive Isocyanate-Terminated Three-Armed- and Hyperbranched Block Copolymeric Tissue Adhesives

Tissue adhesives are an attractive class of biomaterials, which can serve as a treatment for meniscus tears. In this study, physicochemical and adhesive properties of novel biodegradable three-armed- and hyperbranched block copolymeric adhesives are evaluated. Additionally, their degradation in vitro and in vivo, and the tissue reaction after subcutaneous injection in rats are assessed. The developed adhesives have sufficient adhesive strength to meniscus tissue after curing (66-88 kPa). Networks based on the three-armed adhesive have tensile properties that are in the same range as human meniscus. After 26 weeks, networks based on the hyperbranched adhesive show a faster mass loss (25.4%) compared to networks prepared from the three-armed ones (5.5%). Both adhesives induce an inflammatory reaction, however, no necrosis and only initial toxic effects on peripheral tissues are observed. The proposed materials are suitable candidates for the use as resorbable tissue adhesives for meniscus repair.

Analysis of the biliostatic potential of two sealants in a standardized porcine model of liver resection

BACKGROUND

Improved resection techniques has decreased mortality rate following liver resections(LRx). Sealants are known as effective adjuncts for haemostasis after LRx. We compared biliostatic effectiveness of two sealants in a standardized porcine model of LRx.

MATERIAL AND METHODS

We accomplished left hemihepatectomy on 27 pigs. The animals were randomized in control group(n = 9) with no sealant and treatment groups (each n = 9), in which resection surfaces were covered with TachoSil^® and TissuFleece^®/Tissucol Duo^®. After 5 days the volume of ascites(ml), bilioma and/or bile leakages and degree of intra-abdominal adhesions were analysed.

RESULTS

Proportion of ascites was lower in TissuFleece/Tissucol Duo^® group. The ascites volume was lower in TachoSil^® group. In sealant groups, increased adhesion specially in the TachoSil^® group was seen. A reduction of the "bilioma rate" was seen in sealant groups, which was significantly lower in TissuFleece^®/Tissucol Duo^® group.

CONCLUSION

In a standardized condition sealants have a good biliostatic effect but with heterogeneous potentials. This property in combination with the cost-benefit analysis should be the focus of future prospective studies.

Collagen-Fibrinogen Lyophilised Scaffolds for Soft Tissue Regeneration

A significant body of research has considered collagen as a scaffold material for soft tissue regeneration. The main structural component of extra-cellular matrix (ECM), collagen’s advantages over synthetic polymers are numerous. However, for applications where higher stiffness and stability are required, significant cross-linking may affect bioactivity. A carbodiimide (EDC) cross-linking route consumes carboxylate groups that are key to collagen’s essential cell recognition motifs (GxOGER). Fibrinogen was considered as a promising additive as it plays a key role in the process of wound repair and contains RGD integrin binding sites which bind to a variety of cells, growth factors and cytokines. Fibrinogen’s binding sites however, also contain the same carboxylate groups as collagen. We have successfully produced highly interconnected, porous collagen-fibrinogen scaffolds using a lyophilisation technique and micro-computed tomography demonstrated minimal influence of either fibrinogen content or cross-linking concentration on the scaffold structure. The specific biological effect of fibrinogen additions into cross-linked collagen are considered by using films as a model for the struts of bulk scaffolds. By considering various additions of fibrinogen to the collagen film with increasing degrees of cross-linking, this study demonstrates a significant biological advantage with fibrinogen addition across the cross-linking concentrations typically applied to collagen-based scaffolds.

Inhibitory effect of sustained perivascular delivery of paclitaxel on neointimal hyperplasia in the jugular vein after open cutdown central venous catheter placement in rats

PURPOSE

Inhibitory effect of paclitaxel on neointimal hyperplasia after open cutdown has not been elucidated.

METHODS

For the control group (n = 16), silicone 2.7-Fr catheters were placed via the right external jugular vein with the cutdown method. For the treatment group (n = 16), a mixture of 0.65 mg of paclitaxel and 1 mL of fibrin glue was infiltrated around the exposed vein after cutdown. After scheduled intervals (1, 2, 4, and 8 weeks), the vein segment was harvested and morphometric analysis was performed on cross-sections.

RESULTS

Proliferation of smooth muscle cell (SMC) was strongly suppressed in the treatment group, and the ratio of neointima to vein wall was significantly reduced in the treatment group (8 weeks; 0.63 ± 0.08 vs. 0.2 ± 0.08, P < 0.05). Luminal patency was significantly more preserved in the treatment group, and the luminal area was significantly wider in the paclitaxel-treated group compared to the control group (8 weeks; 1.91 ± 0.43 mm² vs. 5.1 ± 0.43 mm², P < 0.05). Mean SMC counts measured at 1 and 2 weeks after cutdown were significantly lower in the treatment group (2 weeks; 115 ± 22 vs. 62 ± 22). Paclitaxel was undetectable in systemic circulation (<10 ng/mL).

CONCLUSION

Sustained perivascular delivery of paclitaxel with fibrin glue was effective in inhibiting neointimal hyperplasia in rat jugular vein after open cutdown.

Development of a fast curing tissue adhesive for meniscus tear repair

Isocyanate-terminated adhesive amphiphilic block copolymers are attractive materials to treat meniscus tears due to their tuneable mechanical properties and good adhesive characteristics. However, a drawback of this class of materials is their relatively long curing time. In this study, we evaluate the use of an amine cross-linker and addition of catalysts as two strategies to accelerate the curing rates of a recently developed biodegradable reactive isocyanate-terminated hyper-branched adhesive block copolymer prepared from polyethylene glycol (PEG), trimethylene carbonate, citric acid and hexamethylene diisocyanate. The curing kinetics of the hyper-branched adhesive alone and in combination with different concentrations of spermidine solutions, and after addition of 2,2-dimorpholinodiethylether (DMDEE) or 1,4-diazabicyclo [2.2.2] octane (DABCO) were determined using FTIR. Additionally, lap-shear adhesion tests using all compositions at various time points were performed. The two most promising compositions of the fast curing adhesives were evaluated in a meniscus bucket handle lesion model and their performance was compared with that of fibrin glue. The results showed that addition of both spermidine and catalysts to the adhesive copolymer can accelerate the curing rate and that firm adhesion can already be achieved after 2 h. The adhesive strength to meniscus tissue of 3.2-3.7 N was considerably higher for the newly developed compositions than for fibrin glue (0.3 N). The proposed combination of an adhesive component and a cross-linking component or catalyst is a promising way to accelerate curing rates of isocyanate-terminated tissue adhesives.

Current advances in three-dimensional tissue/organ printing

Three-dimensional (3D) tissue/organ printing is a major aspect of recent innovation in the field of tissue engineering and regenerative medicine. 3D tissue/organ printing aims to create 3D living tissue/organ analogues, and have evolved along with advances in 3D printing techniques. A diverse range of computer-aided 3D printing techniques have been applied to dispose living cells together with biomaterials and supporting biochemical factors within pre-designed 3D tissue/organ analogues. Recent developments in printable biomaterials, such as decellularized extracellular matrix bio-inks have enabled improvements in the functionality of the resulting 3D tissue/organ analogues. Here, we provide an overview of the 3D printing techniques and biomaterials that have been used, including the development of 3D tissue/organ analogues. In addition, in vitro models are described, and future perspectives in 3D tissue/organ printing are identified.

The Effect of Fibrin Sealant Combined with Fibrinolysis Inhibitor on Reducing the Amount of Lymphatic Leakage after Axillary Evacuation in Breast Cancer

Background and Aims:

One third of women undergoing mastectomy with axillary evacuation for primary breast cancer suffer from postoperative seromas leading to unnecessary costs and complications such as infections and new operations. Different methods to prevent seroma formation have been tried without permanent success. The aim of this prospective randomised study was to examine the effect of fibrin sealant with fibrinolysis inhibitor firstly on the reduction of the amount of lymphatic leakage after axillary evacuation and secondly on the reduction of days with drains and postoperative seroma punctures.

Methods:

40 patients with primary breast cancer were prospectively randomised to the treatment group (n = 19) getting fibrin clue combined with fibrinolysis inhibitor (aprotinin) sprayed into the axillary fossa and to the control group (n = 21).

Results:

There were no differences in the incidence of postoperative seromas between the groups. However, the seromas were easier to treat if fibrin clue was used. Total quantity (mean ± SD) of lymphorrhea and total number of aspirations (mean ± SD) were almost twice as high in the patients of the control group compared to those having fibrin sealant. In the treatment group seromas resolved after one or occasionally after two aspirations in 71 % of patients, while in the control group 90 % of patients needed three or more aspirations.

Conclusion:

Potentially, fibrin sealant combined with fibrinolysis inhibitor might be used for the treatment of post-axillary evacuation lymphorrhea and seroma.

Reactive oxygen species and bacterial biofilms in diabetic wound healing

Chronic wounds are a common and debilitating complication for the diabetic population. It is challenging to study the development of chronic wounds in human patients; by the time it is clear that a wound is chronic, the early phases of wound healing have passed and can no longer be studied. Because of this limitation, mouse models have been employed to better understand the early phases of chronic wound formation. In the past few years, a series of reports have highlighted the importance of reactive oxygen species and bacterial biofilms in the development of chronic wounds in diabetics. We review these recent findings and discuss mouse models that are being utilized to enhance our understanding of these potentially important contributors to chronic wound formation in diabetic patients.

Meta-analysis of the use of surgical sealants for suture-hole bleeding in arterial anastomoses

BACKGROUND

Suture-hole bleeding in arterial anastomoses prolongs operating time and increases blood loss, particularly with the use of prosthetic grafts. Surgical sealants (such as fibrin) may be used as haemostatic adjuncts in vascular surgery. This is a systematic review and meta-analysis of published studies that investigated the utility of surgical sealants in arterial-to-prosthetic graft anastomoses.

METHODS

A systematic review was undertaken of papers published until January 2015 on Embase, MEDLINE, PubMed, PubMed Central and Cochrane databases that analysed the use of surgical sealants as haemostatic adjuncts after arterial anastomoses. RCTs were included, with study endpoints of time to haemostasis or haemostasis at 5 min. Secondary outcomes included treatment failure, mean difference in estimated blood loss and duration of surgery. Sensitivity and subgroup analyses were performed, as well as funnel plot analysis for publication bias.

RESULTS

A total of 2513 citations were reviewed; 19 RCTs comprising 1560 patients were ultimately included in the analysis. The majority of studies compared fibrin sealant with control haemostatic measures. Pooled analysis suggested that surgical sealants reduced the time to haemostasis (mean difference 243·26 (95 per cent c.i. 183·99 to 302·53) s; P < 0·001), improved haemostasis at 5 min (odds ratio 4·50, 95 per cent c.i. 2·59 to 7·81; P < 0·001), and were associated with less treatment failure, blood loss and shorter duration of surgery.

CONCLUSION

Surgical sealants appear to reduce suture-hole bleeding significantly in vascular prosthetic graft anastomoses compared with standard haemostatic measures.

Fabrication and characterization of platelet-rich plasma scaffolds for tissue engineering applications

Platelet-Rich Plasma (PRP), as a rich source of growth factor, can form a fibrin gel that recapitulates the extracellular matrix of the tissues. The aim of this study was to evaluate the effects of different concentrations of CaCl₂ on the PRP scaffold structure which in turn could change the cell's behavior. PRP was mixed with 2.5, 5 and 10% (w/v) CaCl₂. Then, the tensile strength, biodegradability and water content of the scaffolds were evaluated. We also performed immunostaining for assessment of the actin stress fiber orientation and SEM for detecting the cell phenotype and physical properties of the fibers. Cell viability, attachment and migration were also evaluated. The highest cell attachment and short term proliferation rate was observed on the scaffolds with 2.5% CaCl₂. The cells cultured on the scaffold with higher CaCl₂ concentration had fusiform phenotype with few cell processes and parallel arrangement of stress fibers while those cultured on the other scaffolds were fibroblast-like with more processes and net-like stress fibers. The scaffolds with 10% CaCl₂ demonstrated the highest osmolarity (358.75±4.99mOsmole), fiber thickness (302.1±54.3nm), pore size (332.1±118.9nm²) and the longest clotting time (12.2±0.776min) compared with the other scaffolds. Water content, branching angle, porosity, orientation and tensile strength did not change by gelation with different CaCl₂ concentrations. In conclusion, the cell shape, viability and proliferation were modified by culturing on the PRP scaffolds prepared with various concentrations of CaCl₂, and as a result, the scaffolds showed different physical and biological properties.

Fibrin-sealant-delivered cisplatin chemotherapy versus cisplatin hyperthermic intraperitoneal perfusion chemotherapy for locally advanced gastric cancer without peritoneal metastases: a randomized phase-II clinical trial with a 40-month follow-up

A new intraoperative cisplatin administration method for patients with locally advanced gastric cancer (AGC) and without peritoneal metastasis, fibrin-sealant-delivered cisplatin chemotherapy, was reported, and its safety, pharmacokinetics, and efficacy were compared with cisplatin hyperthermic intraperitoneal perfusion chemotherapy. Forty-two AGC patients were randomly divided into 2 groups: fibrin-sealant-delivered cisplatin chemotherapy (FS) (n = 21) and cisplatin hyperthermic intraperitoneal perfusion chemotherapy (CHIC) (n = 21). Both groups received 120 mg cisplatin after complete cytoreductive surgery. At different time points, cisplatin concentrations in patients' sera and urine samples were measured to determine time-dependent maximal concentration (Cmax) and the area under the curve (AUC). The primary and secondary end-points were overall survival (OS) and safety profiling, respectively. Occurrence of grade-3 to grade-4 liver or kidney dysfunction was less frequent in the FS group than in the CHIC group (28.6 % vs 47.6 %). Cisplatin Cmax and AUC for the serum and urine of the FS patients were significantly lower than that of the CHIC patients. Elimination half-life of cisplatin in the FS group was significantly longer than in the CHIC group (24.1 h vs 14.2 h). After a median follow-up of 40 months, 1-, 2-, and 3-years OS were 90.5 %, 71.4 %, and 61.9 % in the FS group, and 61.9 %, 47.6 %, and 42.8 % in the CHIC group, respectively. The median OS was 35.9 months in the FS group and 29.1 months in the CHIC group. Fibrin-sealant-delivered cisplatin chemotherapy was as effective and had a favorable pharmacokinetic profile with similar survival outcomes as cisplatin hyperthermic intraperitoneal perfusion chemotherapy following complete cytoreductive surgery of locally advanced GC without peritoneal metastases.

Three-Dimensional Printing of Tissue/Organ Analogues Containing Living Cells

The technical advances of three-dimensional (3D) printing in the field of tissue engineering have enabled the creation of 3D living tissue/organ analogues. Diverse 3D tissue/organ printing techniques with computer-aided systems have been developed and used to dispose living cells together with biomaterials and supporting biochemicals as pre-designed 3D tissue/organ models. Furthermore, recent advances in bio-inks, which are printable hydrogels with living cell encapsulation, have greatly enhanced the versatility of 3D tissue/organ printing. Here, we introduce 3D tissue/organ printing techniques and biomaterials that have been developed and widely used thus far. We also review a variety of applications in an attempt to repair or replace the damaged or defective tissue/organ, and develop the in vitro tissue/organ models. The potential challenges are finally discussed from the technical perspective of 3D tissue/organ printing.

Development of biodegradable hyper-branched tissue adhesives for the repair of meniscus tears

Meniscus tears are one of the most commonly occurring injuries of the knee joint. Current meniscus repair techniques are challenging and do not bring fully satisfactory results. Tissue adhesives are a promising alternative, since they are easy to apply and cause minimal tissue trauma. In this study, a series of amphiphilic copolymers based on polyethylene glycol, trimethylene carbonate and citric acid were synthesized and subsequently end-functionalized with hexamethylene diisocyanate to form reactive adhesive materials. The shear adhesive strength of the networks to bovine meniscus tissue measured in a lap-shear adhesion test ranged between 20 and 80 kPa, which was better than for fibrin glue (10 kPa). The elastic modulus of the networks depended on composition and was in the same range as that of human meniscus. Cell compatibility was assessed using Alamar Blue staining after incubation of the bovine meniscus cells with different concentrations of the glues for 7 days. Cell viability was not affected after adding up to 3mg of the adhesive/mL of medium. The proposed materials are suitable candidates to be used as resorbable tissue adhesives for meniscus repair. They have excellent mechanical and adhesive properties that can be adjusted by varying the composition of the copolymers.

STATEMENT OF SIGNIFICANCE

Meniscal tears often occur and current treatment strategies do not bring fully satisfactory results. Use of biodegradable tissue adhesives would be an interesting option, but currently available adhesives are not suited due to toxicity or poor mechanical properties. Here, we describe the development of novel biodegradable, hyper-branched, adhesive copolymers. These adhesives cure upon contact with water forming flexible networks. Their adhesion to bovine meniscus tissue was significantly better than that of clinically used fibrin glue. The tensile properties of the cured networks were in the same range of values of the human meniscus. When physiologically relevant amounts were added to cells in culture, not toxic effects were observed. Therefore, the proposed materials are interesting resorbable tissue adhesives for meniscus repair.

Poly(trimethylene carbonate)-based polymers engineered for biodegradable functional biomaterials

This review presents recent examples of applications and functionalization strategies of poly(trimethylene carbonate), its copolymers, and its derivatives to exploit the unique physicochemical properties of the aliphatic polycarbonate backbone.

Tissue sealants in endoscopic applications for anastomotic leakage during a 25-year period

BACKGROUND

Anastomotic leakage after gastrointestinal operation is a complication difficult to manage because conservative therapy and/or reoperation may be unsuccessful and carry the risk of increased morbidity and mortality. The endoscopic use of tissue sealants appears to be a promising alternative to avoid operation.

METHOD

We present conclusively our 25-year experience with tissue sealing in a series of 63 patients referred after gastrointestinal anastomosis leakage; 48 of the upper and 15 of the lower gastrointestinal tract, experiencing a drainage volume ranging 50-2,400 mL.

RESULTS

Tissue glue was applied orally in 37, anally in 10, through the fistula tract in 8, and through a combination of approximation routes in another 8 cases. Biological glue (fibrin) was used in 47, cyanoacrylate in 8, and both glue types in another 8 patients. The total volume of fibrin applied was 2-36 mL, in a median of four sessions, 0.5-4 mL for cyanoacrylate, in a median of two sessions, and, whenever a combination of glues was used, a volume of 12-40 mL of fibrin plus 1-4 mL of cyanoacrylate, in a median of nine sessions. The median hospital stay after initiation of gluing was 14 days (range 8-32). The clinical and technical success rate was 96.8% (61 of 63 patients).

CONCLUSION

Tissue glue appears to be a valuable clinical tool that would prevent further operative interventions and the associated morbidity and mortality after a gastrointestinal anastomosis dehiscence. However, it must be borne in mind that repeated sessions and large volumes of sealants are necessary in many cases.

Antitumor effect of fibrin glue containing temozolomide against malignant glioma

Temozolomide (TMZ), used to treat glioblastoma and malignant glioma, induces autophagy, apoptosis and senescence in cancer cells. We investigated fibrin glue (FG) as a drug delivery system for the local administration of high-concentration TMZ aimed at preventing glioma recurrence. Our high-power liquid chromatography studies indicated that FG containing TMZ (TMZ-FG) manifested a sustained drug release potential. We prepared a subcutaneous tumor model by injecting groups of mice with three malignant glioma cell lines and examined the antitumor effect of TMZ-FG. We estimated the tumor volume and performed immunostaining and immunoblotting using antibodies to Ki-67, cleaved caspase 3, LC3 and p16. When FG sheets containing TMZ (TMZ-FGS) were inserted beneath the tumors, their growth was significantly suppressed. In mice treated with peroral TMZ plus TMZ-FGS the tumors tended to be smaller than in mice whose tumors were treated with TMZ-FGS or peroral TMZ alone. The TMZ-FGS induced autophagy, apoptosis and senescence in subcutaneous glioma tumor cells. To assess the safety of TMZ-FG for normal brain, we placed it directly on the brain of living mice and stained tissue sections obtained in the acute and chronic phase immunohistochemically. In both phases, TMZ-FG failed to severely damage normal brain tissue. TMZ-FG may represent a safe new drug delivery system with sustained drug release potential to treat malignant glioma.

[Topical haemostatic agents and tissue adhesives]

In the last ten years the hemostatic agents and tissue adhesives have been frequently used and they are positive alternatives to prevent excessive blood loss. The objective of this review is to discuss the characteristics of each of these agents to facilitate the surgeon's decision when choosing the most suitable product for every type of bleeding and nature of hemorrhage. A survey of the literature on the subject, in English and in Portuguese, was conducted using PubMed (www.pubmed.com) and Google (www.google.com.br) to find recent articles on the topic. Based on these studies, the authors conducted a didactic review on the hemostatic agents and tissue adhesives and concluded that there is a hemostatic agent to be used in each specific scenario.