Technical manual for manufacturing autologous fibrin tissue adhesive

Production of a composite hyaluronic acid/gelatin blood plasma gel for hydrogel-based adipose tissue engineering applications

Standard approaches to soft-tissue reconstruction include autologous adipose tissue transplantation, but most of the transferred adipose tissue is generally reabsorbed in a short time. To overcome this problem, long lasting implantable hydrogel materials that can support tissue regeneration must be produced. The purpose of this study was to evaluate the suitability of composite 3D natural origin scaffolds for reconstructive surgery applications through in vitro tests. The Young's modulus of the glutaraldehyde crosslinked hyaluronic acid/gelatin (HA/G) plasma gels, composed of human platelet-poor plasma, gelatin and human umbilical cord hyaluronic acid, was determined as 3.5 kPa, close to that of soft tissues. The composite HA/G plasma gels had higher porosity than plain plasma gels (72.5% vs. 63.86%). Human adipose tissue derived stem cells (AD-MSCs) were isolated from human lipoaspirates and characterized with flow cytometry, and osteogenic and adipogenic differentiation. Cell proliferation assay of AD-MSCs on the HA/G plasma gels revealed the nontoxic nature of these constructs. Adipogenic differentiation was distinctly better on HA/G plasma gels than on plain plasma gels. The results showed that the HA/G plasma gel with its suitable pore size, mechanical properties and excellent cell growth and adipogenesis supporting properties can serve as a useful scaffold for adipose tissue engineering applications.

Enhanced cryoprecipitate for skin graft and donor site wound healing in pigs

Due to similarities in skin characteristics, the authors hypothesise that a pig model would most accurately show the ability of autologous, enhanced cryoprecipitate (eCryo) to improve the wound healing of split-thickness skin grafts (STSGs) and corresponding donor sites. Fifty-two STSGs (5 × 5 cm) were fashioned and treated according to a randomised protocol with an autologous eCryo-treated and a control group. Macroscopic assessment, histological evaluation and cellular composition were completed at days 7, 14, 21 and 28. Thirty-two donor sites were also created and assessed in a similar manner. Histologic analysis showed enhancement of healing over all time points for eCryo-treated donor sites. All other results showed no statistically significant improvement with the use of eCryo. Autologous cryoprecipitate appears to be a safe, inexpensive and easy-to-use alternative to fibrin glue, which carries risks and is, in many cases, prohibitively expensive. Further studies are necessary to evaluate the full potential of eCryo. Interestingly, eCryo application may improve donor site aesthetic appearance. We believe that a pig model most reliably simulates eCryo's behaviour in humans to accurately reflect its future clinical applicability.

Novel cryoprecipitate for wound healing and skin grafts in rats

The authors sought to evaluate the ability of locally administered enhanced cryoprecipitate (eCryo) to improve the wound healing of split thickness skin grafts (STSG) and their donor sites. An STSG (5 x 5 cm) was harvested on the back of 30 rats and divided into four areas that were then treated in one of the following groups: A: 'standard' dressing without STSG; B: eCryo without STSG; C: eCryo with STSG coverage and D: STSG alone. Macroscopic and histological assessments (histomorphometric grading scale and cellular composition) were evaluated at days 7, 14, 21 and 28 for wound healing. All wound beds as well as STSGs healed well without any complications. Eighty per cent of the STSG showed a histological graft take of >75% after 28 days. There were no statistically significant differences of macroscopic or histological results between the groups at any time point. Preparation of eCryo is easy and effective. Its use as an adhesive for STSGs is safe and shows similar results as controls. The theoretical benefits of eCryo did not show significant differences. Possible reasons as well as important findings for future research on wound healing are discussed.

A anorectal fistula treatment with acellular extracellular matrix: A new technique

AIM: To investigate a new technique of the anorectal fistula treatment with acellular extracellular matrix (AEM).

METHODS: Thirty patients with anorectal fistula were treated with AEM. All fistula tracts and primary openings were identified using conventional fistula probe. All tracts were curetted with curet and irrigated with hydrogen peroxide and metronidazole. The AEM was pulled into the fistula tract from secondary to primary opening. The material was secured at the level of the primary opening. The excess AEM was trimmed at skin level at the secondary opening.

RESULTS: All of the 30 patients had successful closure of their fistula after a 7-14 d follow-up. The healing rate of anal fistula in treatment group was 100%. The ache time, healing time and anal deformation of treatment group were obviously superior to traditional surgical methods.

CONCLUSION: Using AEM anal fistula plug in treatment that causes the anorectal fistula is safe and successful in 100% of patients. It can reduce pain, shorten disease course and protect anal function.

Comparison of a Plasma-based Composite Biologic Sealant With Fibrin Glue (Tisseel??) for Vascular Anastomoses

Biologic sealants are needed in numerous, more and more demanding, procedures--especially with developments occurring in endovascular and laparoscopic vascular techniques. An initial pilot study in dogs showed that a 4-cm aortotomy closed with a polyester patch sutured in place by a 4-mm-spaced running suture consistently led to massive hemorrhage. We then designed a study using five dogs where two aortotomies were done to compare the effect of Tisseel to that of an autologous sealant prepared in our laboratory. Arterial pressures and heparinization were maintained throughout the surgical procedure. Both biologic sealants prevented hemorrhage from the arteriotomy at unclamping. Macroscopic and histologic assessments were performed. At killing, one week later, the autologous sealant exhibited less blood saturation of the collagen sponge compared with Tisseel. The use of autologous plasma combined with other adhesive components could be an efficient alternative to allogenic fibrin glue. Further studies are needed to confirm these observations.

The use of fibrin glue in skin grafts and tissue-engineered skin replacements: a review

Fibrin glue has been widely used as an adhesive in plastic and reconstructive surgery. This article reviews the advantages and disadvantages of its use with skin grafts and tissue-engineered skin substitutes. Fibrin glue has been shown to improve the percentage of skin graft take, especially when associated with difficult grafting sites or sites associated with unavoidable movement. Evidence also suggests improved hemostasis and a protective effect resulting in reduced bacterial infection. Fibrin, associated with fibronectin, has been shown to support keratinocyte and fibroblast growth both in vitro and in vivo, and may enhance cellular motility in the wound. When used as a delivery system for cultured keratinocytes and fibroblasts, fibrin glue may provide similar advantages to those proven with conventional skin grafts. Fibrin glue has also been shown to be a suitable delivery vehicle for exogenous growth factors that may in the future be used to accelerate wound healing.

Repair of fistulas-in-ano using fibrin adhesive: long-term follow-up

PURPOSE

Fibrin adhesive has been successfully used to treat fistulas-in-ano, but long-term data have been lacking. We report the results of our 18-month study examining the repair of fistulas-in-ano using autologous and commercial fibrin adhesive.

METHODS

A 79-patient, prospective, non-randomized clinical trial was performed in which fibrin adhesive was used to repair fistulas-in-ano. Twenty-six patients were treated with autologous fibrin tissue adhesive made from their own blood, and 53 patients were treated with commercial fibrin sealant. In the operating room the patient underwent an examination under anesthesia, with an attempt to identify the primary and secondary fistula tract openings. The fistula tract was then curetted. Fibrin adhesive was injected into the secondary fistula tract opening until adhesive was seen coming from the primary opening. A petroleum jelly gauze was then applied over both the primary and secondary openings, and the patient was sent home. Follow-up visits occurred one week, one month, three months, and one year later.

RESULTS

Fourteen of 26 (54 percent) patients treated with autologous fibrin tissue adhesive made from their own blood had complete closure of their fistulas after a one-year follow-up, whereas 34 of 53 (64 percent) patients treated with commercial fibrin sealant had closure of their fistulas. Most treatment failures occurred within the first 3 months, but late failures were seen as far as 11 months postoperative.

CONCLUSIONS

Fibrin tissue adhesive offers a unique mode of managing fistulas-in-ano, which is surgically less invasive, but recurrences up to one year later are being seen. Longer follow-up and further research is recommended for improvement.