PLATELTEX®, PLATELET RICH-PLASMA (PRP) AND TISSEEL® SEALANTS: BIOLOGIC COMPARISON.
The surgeon has a selection range of biologics to choose from in the form of readily available fibrin sealant gel, platelet gel, and platelet gel derived growth factors such as PDGF, TGF, EGF AND VEGF. The purpose initially is to start with a wound sealant to reduce fluid collections ( i.e. blood, serous fluid) by adherence of the wound surfaces together, then to allow in-growth of fibroblasts into a stabilized fibrin scaffold ( Tisseel®) or stimulate wound healing and cellular repair by release of growth factors ( i.e. PDGF. VEGF) from platelets such as found in platelet-rich plasma or platelet-gel ( Plateltex®).
PLATELET RICH PLASMA (PRP) AND PLATELTEX®-GEL: BIOLOGICAL ASPECTS RELEVANT TO PRACTICE
The clinical application, efficacy and advantages of autologous PRP, platelet gel, have previously been reviewed by Du Toit et al of The University of Stellenbosch (2007) and Marx et al of The University of Miami (2005). Important clinical issues, include use of registered CE marked blood collection tubes (REGENKIT®, THT tubes) or equivalent, correct centrifugation process and proper activation with calcium. Uncontrolled use of plain tubes, destined for other use, render small amounts of plasma, PRP, platelet yields and therefore cannot be recommended for clinical use. Mazzucco et al of Italy (2008) in a landmark scientific publication on Plateltex® have also high-lighted the benchmark quantification data of REGENLAB PRP, regarding mean platelet recovery and platelet-derived growth factor AB (PDGF-AB), compared to 8 other PRP generation products . Borzini et al of Italy, and strong proponents of the use of PRP and platelet gels, have emphasized the importance of standardization and quality control of platelet derivatives; it is clinical relevant to use systems that guarantee at least 4-5 fold enrichment of the basal whole-blood content of the platelet concentration. His group has demonstrated rapid gelation times with the use of the Plateltex® Activator kit. The efficacy of PRP in promoting cell proliferation and collagen production regarding human tenocytes ex vivo, has been demonstrated during 2008 by a Dutch Group in Rotterdam, working independently. Becaplermin ( Regranex®), a human-platelet-derived growth factor, but not device, can also enhance healing of diabetic foot ulcers, and emphasizes the value of platelet-derived growth factors in the treatment of chronic ulcers. Even VEGF containing creams are available for the treatment of chronic, indolent leg ulcers.
FIGURE 1: REGENLAB® KIT: Venesection kit and blood collection. For preparation of PRP in THT tubes. Available from Omnimed (Pty)., Ltd., JHB, South Africa.
Some research groups, have successfully engineered REGENLAB® PRP derived from THT blood collection tubes and PLATELTEX®, onto sodium carboxymethylated cellulose fibre ( Hydrofibre™), as a biocomposite-scaffold, entrapping human platelets in PRP. By weekly application, together with off-loading shoe-ware, amelioration of superficial diabetic foot ulceration has been possible, when conventional treatment failed. This tentatively confirms the results of other workers involved in the biological treatment of diabetic foot ulceration with PRP and platelet growth factors. The PLATELTEX® activation kit, popular in Europe, ensures very rapid gelation and production of an excellent platelet and fibrin gel for acute and chronic ulcer treatment. This reduces spillage of the gel during topical application. The new generation of PRP activation, provides for excellent platelet recovery, collection efficiency and PDGF-AB availability. Gelation of the PRP is induced by the enzyme batroxobin, and therefore differs from other devices that rely on thrombin. In this case the platelets treated with batroxobin do not become activated; become passively entrapped in the fibrin network, and GF release occurs slowly . This observation could theoretically tailor the slow release of GF over a prolonged period allowing a better anabolic and biological effect for wound healing. This may be preferable to quick thrombin-induced growth factor release. Batroxobin only removes fibropeptide A, whereas thrombin catalyses the release of both fibropeptide A and B. Clearly, this new approach has potential application in soft and bony tissue repair via the topical route. In Europe, Plateltex® is registered as a medical device (CE 0476), sterile disposable device, for blood component manipulation ex vivo and the preparation of biologically active platelet gel, fibrin gel and bone marrow derived cells for tissue repair. Batroxobin activator does not exert pharmacological activity after topical gel administration. In Europe, clinical trials have been authorised using PRP-gel preparation including activation with batroxobin. PRP-gel has not been considered a somatic cell therapy product.
Batroxobin, is isolated from snake venom (Bothrops atrox, B.Moojeni, B.Jacaraca) and is a serine protease consisting of 231 amino acids. Data show that it is a thrombin-like enzyme with haemostatic and defibrination characteristics. It has been used in peripheral arterial circulatory disorders including the treatment of stroke. Plateltex®, is available in 3 kits ( models 0/0, 35/70, and 70/100). These provide for preparation of PRP, platelet gel, fibrin gel, and bone marrow-derived cells. Plateltex® is directed at point of care: ulcer treatment, dental and periodontal surgery, peri-anal fistula and fissure surgery, aesthetic medicine and cosmetics, ophthalmology and sports medicine. It is also suitable for major surgery, such as orthopaedic and arthroscopic procedures, oral maxillofacial interventions and cardiac surgery. The product also has application in veterinary surgery and tissue engineering ex vivo in the laboratory. Major advantages include acceleration of wound healing and regeneration time, potential to reduce post-operative complications, autologous nature, rapid incorporation of skin and bone grafts and incorporation of implants. Rapid gelation this way obviates the need for bovine thrombin.
Growth factors, released by platelets that influence wound healing include, EGF, TGF-alpha, PDGF, FGF, TGF-beta, and VEGF(8). These factors play critical roles in epithelial proliferation, monocyte chemotaxis, fibroblast migration and proliferation, angiogenesis, collagen synthesis and collagenase secretion (4, 8). Knowledge of GF is important, but careful assessment and integrated technical management of wound exudate is of no lesser importance. This includes the optimal use of surgical dressings that address absorption, fluid retention, and sequestration of exudates, evaporation and transmission. Both L-Mesitran® ( Triticum Wound Care) and Aquacel® ( Convatec™, a Bristol Meyers Squibb Company) have special indications in wound healing and care, and can be strongly recommended in surgical practice. Previous studies show that Aquacel®, can promote angiogenesis, that is a critical arm of wound healing and repair. In Europe, synthetic surgical dressings, such as Aquacel® and Aquacel Silver®, remain benchmark in chronic wound care and repair. Efficacy of Plateltex® in enhancing wound healing is reflected in figures 8-10. For the moment, tumour surgery is an exclusion criterion for the use of platelet gel or administration of GF into the wound.
FIGURE 2: PLATELTEX® ACTIVATION KIT.
IMPORTANT GROWTH FACTORS RELEVANT TO THE APPLICATION OF PRP AND PLATELTEX®
SUMMARY OF POINT-OF-CARE FOR THE APPLICATION OF PLATELTEX®
- Chronic lower leg ulceration
- Dentistry and periodontal surgery
- Colo-rectal surgery: fissures and fistula-in-ano
- Aesthetic medicine and cosmetics
- Sports medicine
- Major surgery: orthopaedic and arthroscopic surgery, oral maxillofacial surgery, cardiac surgery)
- Other: veterinary, in-vitro cell biology/ tissue culture
PLATELTEX® KITS AVAILABLE: MATERIALS AND PROCESS READY TO USE IN 25 MINUTES
- Model Act 0/0 ( fast induction and generation of PRP)
- Model 35/70 ( preparation of 5-10 ml PRP)
- Model 70/100 (preparation of 10-20 ml of PRP for dressing large skin ulcers). All CE marked.
TISSEEL®: FIBRIN SEALANT
For decades, topically applied Tisseel® Fibrin Sealant ( Baxter®) in the operating room, has remained the gold standard and market leader regarding wound sealants; improved haemostasis, reduced blood loss, tighter sealing of sutures due to fibrin formation. Tisseel® is marketed in South Africa by Adcock-Ingram Critical Care. A classic tissue glue with sealing, haemostatic and gluing properties. Concentrated fibrinogen-aprotinin solution and factor XIII, thrombin and calcium chloride reduce oozing, by coagulation in the operative field. The solidified Tisseel®/Tissucol® Fibrin Sealant provides a stabilized matrix for ingrowing fibroblasts and therefore promotes support of granulation tissue, revascularization and re-epitheliazation. All elements critical during wound healing and repair by primary intention. An important focus of Tisseel® is predominantly fibrin sealage and haemostasis, whilst Regen® and Plateltex® PRP gel provide platelets and GF destined for repair and regeneration in the form of cell therapy. Product safety has been enhanced by new manufacturing technology. Currently, it remains to be demonstrated that the haemostatic-sealant properties of platelet-gel products are superior to those of Tisseel®.
Tisseel® Fibrin Sealant is a biological two component sealant which is totally absorbed during the wound healing process. Two products are available: Tisseel® Kit and Tisseel® Duo. Composition of the kits is as follows: clottable protein (fibrinogen, plasma fibronectin, factor XIII, aprotinin (bovine), plasminogen, human thrombin and calcium chloride. Administration is via the Duploject® Application System. The manufacturer provides the following important clinically applicable information:
- The Fibrin Sealant® contains sufficient factor XIII to ensure a high-degree of alpha-chain cross-linkage. This is important for optimal clot rigidity.
- The biomechanics behaviour of the fibrin clot is attributable to the dense, netlike structure of cross-linked fibrin. This can be enhanced by the combined use of collagen fleece.
- Studies show that the Fibrin Sealant® can provide a biological matrix suitable for ingrowing fibroblasts from the host. The fibroblasts adhere to the fibrin due to fibronectin, a surface protein of fibroblasts, which is cross-linked with fibrin by factor XIIIa. The stabilized fibrin network enhances monolayer migration that can be confirmed by SEM. The enhancement of wound granulation tissue, enhanced epithelialization and fibroblast proliferation ex-vivo are strong evidence that this is the case in-vivo.Ex-vivo studies also indicate that fibrin sealant is a natural barrier against bacterial pathogen overgrowth.
The biological principles of coagulant sealing with Fibrin Sealant® are as follows:
- Haemostasis ( thrombin converts fibrinogen into monomeric fibrin by splitting off fibrino-peptides A and B.). Aggregation of the fibrin molecules form a mesh in which cellular elements are imbedded.
- Formation of a stable physiological fibrin structure. This provides for optimal tissue adhesion, haemostasis, sealing and wound healing.
- Complete healing: Fibroblasts and pluripotent endothelial cells start to proliferate from the wound edges into the blood clot and structural fibrin framework. The clot is converted to fibrous tissue. Studies show that Tisseel® is biocompatible with the ECM. Cellular infiltration of macrophages and polymorphonuclear granulocytes into the fibrin coagulum marks the beginning of wound healing. Ingrowth of vascular granulation tissue and fibroblasts follow. With time, the fibrin layer is replaced by fibroblasts and fibrous tissue forming new loose connective tissue.
Tisseel® Fibrin Sealant has been in use in clinical practice for about 20-years and has proved effective in the following divisions of surgery: cardiovascular, neurosurgical, plastic and reconstructive and orthopaedic surgery. Topical sealants can effectively reduce blood loss from the skin donor sites prior to grafting. A recent study from Italy, has demonstrated the value of fibrin sealant in the prevention of major complications following laparoscopic gastric bypass. Morris et al of the Brooke Army Medical Centre have demonstrated the value of fibrin sealant in complex genital reconstructive surgery; end-points of the study included skin graft take, seroma or haematoma formation, drainage and infection. Falanga et al of The Rodger Williams Medical Centre, Rode Island, USA published an important paper on the application of topically applied autologous multipotent mesenchymal stem cells ( MSC) in order to accelerate the healing of human and experimental murine wounds. Fibrin polymer spray was used to enhance cell retention and to facilitate the wound repair process. These workers strongly suggest that autologous bone-marrow derived MSC can be safely and effectively be delivered to wounds using a fibrin spray system. Combining fibroblast growth factor-2 and fibrin sealant may well be useful for promoting regenerative repair of full-thickness defects of articular cartilage in humans. Recent experimental work from Aristotle University of Thessalonika, Greece indicates that application of fibrin glue can prevent the deleterious effects of chemotherapy on colon resection anastomosis. The role of fibrin glue in conjunctival closure in pterygium surgery has been reported by researchers from Golda Campus, Petah Tiqwe, Israel. They show that fibrin glue in pterygium surgery can significantly reduce operative time, patient symptoms, pain and discomfort. Use of fibrin glue for attaching human amniotic membrane graft during primary pterygium surgery has also been reported from India. Thorrez has recently reported the use of cultured human myoblasts and Tisseel® and this will no doubt have important future clinical application.
FIGURE 3: Tisseel Kit. Available from Adcock Ingram, JHB., South Africa.
BOLANDCELL REFERENCES RELEVANT TO THE USE OF PLATELET –RICH PLASMA AND OTHER BIOLOGICS:
- Eur Surg Res 2008: 40; 203-10
- J Extra Corp Technol 2007:39; 177-82
- J Wound Care 2008: 17; 30-2, 34-7.
- IJSS 2007:1;87-95
- Int J Oral Maxillofac Surg 2004: 33; 733-739
- Ject 2006: 38;174-187