Platelet rich plasma

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Platelet-rich plasma (also platelet-rich plasma or PRP ) is produced from autologous patient's whole blood by plasmapheresis with an autotransfusion device or a special table-top device . The separation principle is based on centrifugal force , through which the individual blood components are arranged in layers due to their different specific weights and can then be collected separately (plasmapheresis). The whole blood is separated into the components erythrocytes , platelet-poor plasma (PPP) and platelet-rich plasma (→ blood plasma ). In a second step, a thrombin-rich gel ( autologous platelet gel , APG) can be produced from the separated PRP . This can play an important role in wound healing, especially with chronic wounds. The method promises another positive effect on postoperative bleeding and pain. In the event of bleeding and platelet deficiency, enriched plasma ( platelet concentrate ) from external donors (allogeneic donors) can be used for treatment .

From left to right: erythrocyte , platelet , leukocyte

history

As early as the early 1960s, Schulte described the possibility of treating wound defects with autologous blood. For this purpose, autologous blood was first used and a few years later centrifuged autologous blood was used to fill cysts. However, this work received little international attention. It was not until around 1996 that autologous blood products were used again for hemostasis or as tissue glue. In 1997 a process for the production of PRP was published. In 1998 the first clinical study on the use of PRP on patients in oral surgery was published.

Today, PRP is mainly used in dental, oral and maxillofacial surgery, orthopedics, plastic surgery and the treatment of diabetic wounds, but also in cardio-thoracic and vascular surgery. In the case of many publications from these areas, however, it is only a matter of descriptions of individual cases or case series and only a few papers represent a well-founded scientific investigation. For this reason, the definition of the German Medical Association is correspondingly short.

In the 1990s, PRP was primarily manufactured using devices for automated autotransfusion in complex work steps. Today, in addition to modern autotransfusion devices with semi-automatic programs, there are also a number of table-top devices available from various suppliers that allow the production of PRP with small amounts of blood. Their effectiveness in terms of the quality of the platelet-rich plasma generated has also increased compared to the beginning.

Manufacturing

The amount of blood to be drawn depends on the device used for plasmapheresis. When using a tabletop device, it is around 20 to 100 ml of whole blood. An autotransfusion device requires between 350 and 500 ml. The device used depends on the amount of platelet-rich plasma required. Small table-top devices are mainly used for outpatient and minor surgical interventions (e.g. dentistry, plastic surgery, etc.). Autotransfusion devices are mainly used for major surgical interventions (e.g. cardiac, thoracic and vascular surgery). The blood is taken from the patient by a doctor using the acute normovolemic hemodilution method under control of blood pressure and the provision of volume and fluid replacement. For this larger amount of blood, a blood donation bag is used, which is customary in blood donation and in which citrate prevents the blood from clotting . When using a table-top device, however, blood can be drawn with a syringe.

The whole blood is taken from the patient and centrifuged . The plasma floating above is separated or centrifuged again depending on the method. This achieves a 3 to 4-fold concentration of platelets in a small plasma volume. The amount of PRP generated is between a few milliliters with a tabletop device and up to 50 milliliters with an autotransfusion device. This product must be used within eight hours. There are different details about centrifugal force and duration.

It is one of the advantages of the method that no blood is lost to the patient. Even if larger amounts are withdrawn, the erythrocytes and the platelet-poor plasma can be retransfused after plasmapheresis (→ blood transfusion ), while the platelet-rich plasma is used as planned.

Mode of action

Platelets have a high content of various growth factors and cytokines , such as " Platelet Derived Growth Factor ", " Transforming Growth Factor-β1 and β2 ", " Epidermal Growth Factor " (EGF), " Fibroblast growth factor ", " Epithelial growth factor ", " Insulin-like growth factors "and" Platelet-Derived Angiogenesis Factor ". These factors are released through physiological or artificially induced platelet activation and have a chemotactic , direct and indirect tissue regenerative effect . Mesenchymal stem cells and fibroblasts as well as mononuclear leukocytes are stimulated to proliferation and locally attracted.

Some studies recommend activating the platelets with different amounts of calcium chloride or thrombin (→ autologous platelet gel , APG). Activation of the platelets is particularly useful when wound healing is impaired for various reasons. Because of microcirculation disorders, messenger substances can not get from the wound area into the body's circulation and initiate wound healing. Particularly chronic wounds or large surgical wounds should be mentioned here, for which impaired wound healing is also to be expected.

application

The indications from human, dental and veterinary medicine are diverse: poorly healing wounds, tendinitis, fracture treatment , slow bone regeneration, joint ailments ( arthropathy ), keratitis etc. PRP is often used, especially in oral and facial surgery. It is also increasingly used in cardiac, thoracic and vascular surgery, where PRP is used primarily for the prophylaxis of wound healing disorders. Platelet-rich plasma is now also used in aesthetic surgery , for example in eyelid tightening.

The transfer (transplantation) of platelet-rich plasma is considered to be the manufacture of a drug if the attending doctor or dentist has manufactured it himself. PRP is subject to the Transfusion Act.

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  1. ↑ WV Schulte: The autologous blood filling: a new method for the treatment of larger bone defects after intraoral interventions. In: German Dental Journal. 12, 1960, pp. 910-914.
  2. ↑ WV Schulte: The retraction of the blood clot and its significance for the primary healing of the jawbone. Carl Hanser Verlag, Munich 1964.
  3. ↑ K. Yamamoto, J. Hayashi, H. Miyamura, S. Eguchi: A comparative study of the effect of autologous platelet-rich plasma and fresh autologous whole blood on haemostasis after cardiac surgery. In: Cardiovascular Surgery. 4 (1), Feb. 1996, pp. 9-14.
  4. ^ DH Whitman, RL Berry, DM Green: A technique for improving the handling of particulate cancellous bone and marrow grafts using platelet gel. In: Journal of Oral and Maxillofacial Surgery. 56, 1998, pp. 1217-1218.
  5. ^ RE Marx, ER Carlson, RM Eichstaedt, SR Schimmele, JE Strauss, KR Georgeff: Platelet-rich plasma: Growth factor enhancement for bone grafts. In: Oral Surgery Endod. 85 (6), 1998, pp. 638-646.
  6. ↑ German Medical Association: Guidelines for therapy with blood components and plasma derivatives . 3rd, revised and expanded edition. Cologne 2003.
  7. ↑ GF Giordano, S. Rivers, GKT Chung, RB Mammana, JD Marco, BS Strug: Autologous Platelet-Rich-Plasma in Cardiac Surgery: Effect on Intraoperative and Postoperative Transfusion Requirements. In: Annuals of Thoracic Surgery. 46, 1998, pp. 416-419.
  8. ↑ M. Klein, C. Probst, NO Richter, R. Zotz , HD Schulte, E. Gams: The preoperative autologous thrombocytopharesis to reduce homologous blood transfusions in cardiac surgery. In: Journal of Cardiac, Thoracic and Vascular Surgery. Vol 15, No 2/2001, pp. 43-49.
  9. ↑ CW Smith, RS Binford, DW Holt, DP Webb: Quality assessment of platelet rich plasma during anti-platelet therapy. In: Perfusion. 22, 2007, pp. 41-50.
  10. ↑ Pouria Samadi, Mohsen Sheykhhasan, Hamed Manoochehri Khoshinani: The Use of Platelet-Rich Plasma in Aesthetic and Regenerative Medicine: A Comprehensive Review . In: Aesthetic Plastic Surgery . tape 43 , no. 3 , June 2019, ISSN  1432-5241 , p. 803-814 , doi : 10.1007 / s00266-018-1293-9 , PMID 30552470 .
  11. ↑ R. Burger: On the use of platelet-rich plasma (PRP) by dentists. ( Memento of March 2, 2008 in the Internet Archive ) May 22, 2002.
  12. ↑ German Medical Association: Cross-sectional guidelines (BÄK) for therapy with blood components and plasma derivatives . 4th, updated, revised and expanded edition. 2014.

Web links

  • http://www.perfusion.com/ (English) A much-visited website with links and current references to scientific work and studies on the subject of platelet rich plasma, among others