What Is Platelet Rich Plasma?

Platelet-rich plasma (PRP) is a platelet concentrate obtained from autologous whole blood after centrifugation. PRP contains a large number of growth factors and proteins.

Chinese name: Platelet rich plasma
Foreign name: Platelet-rich plasma, PRP

Contains: A large number of growth factors and proteins
proposer: Hood
Category: Platelet concentrate

Definition of platelet rich plasma

Platelet-rich plasma is a high-concentration platelet-rich plasma obtained by centrifuging whole blood from animals or humans. It can be changed into a gel after adding thrombin, so it is also called platelet-rich gel or platelet-rich leukocyte. Gel (PLG). PRP contains a large number of growth factors such as platelet-derived growth factor (PDGF), transforming growth factor (TGF-), and insulin-like growth factor 1 (IGF-1).

In 1993, Hood et al. First proposed the concept of platelet-rich plasma (PRP), and found that PRP contains abundant platelets, the number of which is more than three times that of whole blood. Platelets contain a large number of growth factors such as platelet-derived growth factor (PDGF), transforming growth factor- (TGF-), insulin-like growth factor (IGF), epidermal growth factor (EGF), and vascular endothelial growth factor (VEGF) Wait. In the field of dentistry and orthopedics, platelet-rich plasma research is very popular.

Biological characteristics of platelet-rich plasma :

The main mechanism of PRP to promote bone regeneration is that it can release some growth factors for the local microenvironment of bone defects. Among them, the growth factors that play the main role are PDGF and TGF- existing in alpha particles _[2] . Most of the TGF- in particles exist in the form of their precursors. When the body is locally injured, its precursors are converted into active transforming growth factor through the exocytosis pathway and activated by some related enzymes. When catalysts such as thrombin and calcium chloride are added to PRP, the growth factors in its platelets are activated and released, thereby promoting the repair and regeneration of various tissues. The study found that when PRP was not activated, the amount of growth factors released by particles in platelets was small, and the amount of growth factor released after activation was greatly increased, and the proliferative effect of activated PRP was significantly stronger than that of the non-activated group. And with the increase of thrombin concentration, the amount of growth factor released by PRP also increased.

Platelet-rich plasma preparation:

At present, the preparation method of PRP has not yet formed a unified standard, and its preparation mainly includes two methods: density gradient centrifugation method and plasma separation and replacement method. Density gradient centrifugation is a method of separating and extracting PRP from whole blood according to the sedimentation coefficient of each component in the blood. Nowadays, secondary centrifugation is commonly used. However, the platelet concentration and activity in PRP prepared by different centrifugal forces and centrifugation times Different. The plasma separation and replacement method uses medical blood component separation equipment to separate whole blood into components such as platelet plasma and concentrated platelets. This method is mainly used for blood platelet collection and clinical component blood transfusion.

Development direction of platelet-rich plasma :

PRP has the advantages of convenient material extraction, simple preparation, and resorbability, which makes it has a broad application prospect in the repair of various tissue defects, especially bone defects. However, the following problems still need to be solved now: There is no uniform standard for the preparation of PRP, and a set of efficient and stable preparation methods need to be established. The standardized preparation of PRP can provide reliable quality assurance for its application in research and clinical. The dose-effect relationship between PRP concentration and tissue regeneration promotion has not been fully elucidated. The activities of various growth factors in PRP, cellular molecular biological mechanisms, and their interactions have not been fully elucidated. PRP is now mainly applied to small-scale bone defects such as oral and maxillofacial regions, and experimental data are lacking in the study of large-scale bone defects and nonunion. Whether the local use of PRP will adversely affect the entire body. Can allogeneic PRP be used instead of autologous PRP to reduce secondary trauma in patients? Allogeneic PRP is widely used in clinical practice. Reliable and repeatable animal experiments should be performed, and standardized population tests should be strictly designed.

Platelet-rich plasma properties

Platelet-rich plasma is prepared from fresh blood by low-speed centrifugation. The collected whole blood is centrifuged at a low speed of 27.5 to 37.5 rpm for 15 to 20 minutes (or 1220 rpm for 5 minutes) at room temperature for 4 to 6 hours, so that the red blood cells and white blood cells basically sink. Retained in the upper layer of plasma, the upper layer of plasma is separated, that is, platelet-rich plasma, and more than 70% of platelets in whole blood can be obtained. Platelet-rich plasma prepared from 200ml of whole blood can collect 2.5-1010 platelets. It is mainly used for the prevention and treatment of bleeding in patients with thrombocytopenia and platelet dysfunction caused by various reasons.

Platelet-rich plasma case

Granger suffered a left knee injury in the playoffs against the Miami Heat last season. After a period of recovery, Granger accidentally caused repeated injuries while training in late summer, and he also received platelet-rich plasma injections.