Platelet-rich Plasma: What is it? How does it work?

By: Aidan Fu ([email protected])

1. Introduction

Platelets play a crucial role in forming ‘scabs’ and plugging wounds, a process vital for healing (University of Rochester Medical Center, 2019). Platelet-rich Plasma (PRP) involves extracting blood from the body and spinning it in a centrifuge to separate red and white blood cells, creating a concentrated solution rich in platelets (Platelet-Rich Plasma (PRP) Injection: How It Works | HSS, 2015).Many athletes use these injections as they stimulate the healing process and provide specific growth factors to speed up recovery time (Yale Medicine, n.d.).

2. Conservative Alternative for Tears

Traditionally, athletes with strained or torn tendons require surgery to repair the damage (MSD Manual Consumer Version, n.d.). However, a conservative alternative involves the use of PRP, which contains a combination of growth factors and chemokines that stimulate the migration of white blood cells (Pavlovic et al., 2016). When PRP is paired with prolotherapy, the injection of an irritant such as dextrose solution to encourage localized inflammation triggers the body’s natural healing processes (Ryu et al., 2018). Dextrose is seen by the body as a threat or injury, hence causing the body to trigger immune and healing responses (Cleveland Clinic, n.d.). There are many advantages to choosing a non-surgical route such as PRP as to choosing surgery (Dr. Swagatesh Bastia, 2023).

• Low effect on lifestyle : With all non-surgical routes, there are less impacts on life such as risk of complications or less recovery time versus surgery.
•  Natural Regeneration: This treatment focuses on stimulating the body’s own healing mechanisms, promoting tissue repair and regeneration.
• Reduced Pain : The majority of the time, patients experience less pain and discomfort compared to surgical options.
• Improved Recovery : Recovery time is typically decreased, and patients can return to activity sooner
• Lower Cost : PRP and Prolotherapy is a non-surgical option, making it cheaper than actual surgery
• Long-Term Benefits : PRP with Prolotherapy not only addresses the ACL injury but also helps with degenerative changes in the knee. It promotes overall knee health and reduces the risk of future injuries such as arthritis.

3. The Manufacturing of PRP 

In the medical world, it is standard that centrifugation is used to isolate different cell components from their medium (Mohammad Sharifian Gh and Fatemeh Norouzi, 2023). Essentially without delving into the calculations and factors such as temperature, viscosity and more, an initial centrifugation is performed to separate the red blood cells from the white blood cells followed by a second centrifugation with the goal of concentrating the platelets (Dhurat and Sukesh, 2014). 

The first spin is performed at constant acceleration to separate the red blood cells from the rest of the blood (Dhurat and Sukesh, 2014). After the initial spin, the blood separates into three parts. An upper layer containing mostly white blood cells and platelets, a middle layer known as the buffy coat consisting of mostly white blood cells and a bottom layer consisting mainly of red blood cells. There are many variations of PRP such as P-PRP or leukocyte poor (little white blood cells) and L-PRP (leukocyte rich, many white blood cells) and L-PRP is known to cause inflammation but not limited to that, it can also cause catabolism which can break down molecules such as collagen, which is why P-PRP is viewed as a more effective method for healing as inflammation can be induced from prolotherapy, meaning an alternative route can be taken to avoid the negative perks of L-PRP (Wang et al., 2018)(Lana et al., 2019). 

The second spin is harder and faster with the goal of concentrating the platelets (Dhurat and Sukesh, 2014). Once finished, there are two layers created. The bottom 1/3 is PRP and the upper 2/3rds is PPP (platelet-poor-plasma). The PPP is then removed and the platelets are suspended into a minimum quantity (2-4ml) of plasma and shaken, creating PRP. (Refer to Fig. 1)

Figure 1: The process of PRP with pictures. (Dhurat and Sukesh, 2014)

4. The Effect of PRP and How it Induces Recovery

Once injected into the target site, the growth factors and other biological materials such as chemokines help to heal the tendon (Everts et al., 2020). Whilst poor in leukocytes, there are still leukocytes such as neutrophils and monocytes. These leukocytes increase the amount of collagen protein production through increases in procollagen expression (Yuan, Zhang and Wang, 2013). There are many different growth factors including PDGF, TGF-β, VEGF, IGF, HGF, EGF, and bFGF which all contribute to recovery in different ways. For example, TGF-β which exists in platelets helps with tendon healing, collagen production and the reduction of scar tissue. Each of these growth factors have a different respective impact, but they each all contribute to the healing. One of the best parts is that these growth factors come from different parts of the blood, meaning there is no chance of the body rejecting these because they are made from each different patient.

5. Conclusion

All types of PRP have the potential to help many people who suffer from tendon damage or conditions such as tendinitis, arthritis and wear and tears (Wang, 2014). With the help of growth factors and chemokines which call more white blood cells to the site of injury, the body is able to non-surgically fix tears without scar tissue (Yuan, Zhang and Wang, 2013). PRP comes with many other benefits such as the relative safety of the injection and low pain compared to surgery (Dr. Swagatesh Bastia, 2023). The best part, however, is how fast and easy it is to make PRP and how powerful it is even though it can be made in half an hour (Dhurat and Sukesh, 2014). When combined with other techniques that speed up healing such as prolotherapy, healing times can be reduced and pain can be decreased (Dr. Swagatesh Bastia, 2023). 

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