Tania Malan INP, MSc Aesthetic Medecine - Anita Woolley - FIBMS Senior Biomedical Scientist 

Purpose:

To determine the composition of PRP obtained from 4 commercial separation kits, which would allow assessment of current classification systems used in cross-evaluation comparisons. 

Introduction:
In the last few decades different concepts have evolved for the best possible tissue regeneration in wounds, surgery and skin (Choukroun 2017, Dohle 2018). The use of PRP and its growth factors is attracting much attention amongst aestheticians, dermatologists and surgeons (Takura, 1996, Yildiz, 2016, Wang, 2016). Platelets contain high quantities of growth factors capable of stimulating cell proliferation (mitogenesis), matrix remodelling (Dohan, 2009) and vascular growth (angiogenesis) (Robert, 2001). See Table 1.

PRP is a relatively new biotechnology which is part of tissue engineering and cellular therapy (Robert, 2001). PRP originated 40 years ago where blood derived products were used to seal wounds and stimulate healing (Dohan, 2009). Some studies found that the drawback from PRP is that the additional use of anticoagulants inhibit wound healing (Wang, 2016). Furthermore, the optimal combination of each cellular component in PRP remains unknown due to the variety of commercially available PRP generating systems, which makes it difficult to know which PRP preparation is best for which clinical indication (Boswell, 2014).

Now a second-generation protocol emerged known as PRF (platelet rich fibrin) or Choukroun’s i-PRF. It differs from PRP in the sense that there is no anticoagulants or additives and are centrifuged at lower speed (Dohan, 2006). PRF has a mixture of platelets, white blood cells, bone morphogenic protein (BMP), stem cells and growth factors (Holistic, 2018). However, these concepts have spurred commercial interest and exploitation with a wide variety of preparation protocols and kits (Dohan, 2009). 

More confusing is the various nomenclature depending on who markets the product such as Vivostat PRF, Fibrinet Platelet Rich Fibrin Matrix (PRFM), Dracula Kit etc. Various classifications also exist such as L-PRP i-PRF, PRF etc. See Table 2. The use of platelet concentrates, and its efficiency is controversial (Dohan, 2009). Dohan (2009) continues that applications and methods leads to a different product with different biology and potential uses. A literature review of the various classifications and impact added to the confusion as the protocols, machines, activation methods are all different.

Furthermore, the literature mention “large” or “rich” concentrates but no real evidence of its numbers could be found within the literature. Therefore, studies are mostly empirical with no real data behind it and no standardisation. The literature remains unclear about the true clinical differences between these related fibrin products (Dohan, 2008). Dohan (2008) continues that the differences between PRP and i-PRF have never been analysed with regards to its leukocyte content or the final concentrate key parameter of platelets and never been accurately documented. The problem is that there is only empirical data available regarding the various centrifuges, protocols and platelet yield (Redaelli, 2010).

The tests are done by “eye” where clinicians or commercial sellers judge the number of platelets which often based on the amount of plasma separated from the red blood cells. The aim of this evaluation was to determine the cell count of 4 commercial kits to accurately measure the difference cell counts,
but most importantly the amount of platelet concentration in each kit.