A Call for a Standard Classification System for Future Biologic Research: The Rationale for New PRP Nomenclature

Abstract

Autologous cell therapies including platelet-rich plasma (PRP) and bone marrow concentrate (BMC) are increasingly popular options for soft tissue and joint-related diseases. Despite increased clinical application, conflicting research has been published regarding the efficacy of PRP, and few clinical publications pertaining to BMC are available. Preparations of PRP (and BMC) can vary in many areas, including platelet concentration, number of white blood cells, presence or absence of red blood cells, and activation status of the preparation. The potential effect of PRP characteristics on PRP efficacy is often not well understood by the treating clinician, and PRP characteristics, as well as the volume of PRP delivered, are unfortunately not included in the methods of many published research articles. It is essential to establish a standard reporting system for PRP that facilitates communication and the interpretation and synthesis of scientific investigations. Herein, the authors propose a new PRP classification system reflecting important PRP characteristics based on contemporary literature and recommend adoption of minimal standards for PRP reporting in scientific investigations. Widespread adoption of these recommendations will facilitate interpretation and comparison of clinical studies and promote scientifically based progress in the field of regenerative medicine.

A multi-center analysis of adverse events among two thousand, three hundred and seventy two adult patients undergoing adult autologous stem cell therapy for orthopaedic conditions

“…Staff at each site were trained in these SOP protocols. Based off the PLRA classification, the type of PRP produced is 1 cc of 14x/−/−/NO [19] but baseline platelet counts were not obtained. In the CE group, MSCs isolated from the bone marrow aspirate were expanded in an autologous based culture media for 12-16 days prior to injection into the joint space (1-3 cc in PL with dose ranges generally from 0.1-6 × 10 7 MSCs) or musculoskeletal structure (see Supplement 1 which elaborates on treatment differences between groups) [14].…”

Effect of intralesional platelet-rich plasma (PRP) treatment on clinical and ultrasonographic parameters in equine naturally occurring superficial digital flexor tendinopathies – a randomized prospective controlled clinical trial

“…The optimal platelet to leucocyte ratio for treatment of tendinopathy is unknown to date and most probably dependent on the stage of tendon healing [76]. …”

Contributions for Classification of Platelet Rich Plasma – Proposal of a New Classification: MARSPILL

“…Mautner et al (2015) described some variable that, in the author's opinion, none of the previously published PRP classifications present all the characteristics that may influence PRP activity and efficacy. In this context, the authors evidenced that is important to describe the platelet count (absolute number/μl), leukocyte content (as positive or negative) and, when presented, described the percentage of neutrophils, red blood cells content (as positive or negative), and activation (yes or no for exogenous activation) -Platelet, leukocyte, red blood cells and activation (PLRA) classification [23]. Magalon et al (2016) published another classification based on four components: (1) dose of injected platelets, (2) efficiency of the production, (3) the purity of PRP obtained, and (4) activation process.…”

“…Another parameter used in this classification relates to the use of agonists to activate PRP (type II and IV) or not (type I and III) [22]. Mautner et al (2015) described some variable that, in the author's opinion, none of the previously published PRP classifications present all the characteristics that may influence PRP activity and efficacy. In this context, the authors evidenced that is important to describe the platelet count (absolute number/μl), leukocyte content (as positive or negative) and, when presented, described the percentage of neutrophils, red blood cells content (as positive or negative), and activation (yes or no for exogenous activation) -Platelet, leukocyte, red blood cells and activation (PLRA) classification [23].…”