An important and overlooked parameter in platelet rich plasma preparation: The mean platelet volume

Platelet-Rich Plasma: Advances and Controversies in Hair Restoration and Skin Rejuvenation

BACKGROUND

Platelet-rich plasma (PRP) and its combined therapeutic modalities have catalyzed new possibilities in dermatology; however, limitations in evidence and lack of consensus remain among clinicians regarding optimal composition, protocol, technique, and application.

OBJECTIVE

To provide an update and analysis of the evidence for PRP in hair restoration and skin rejuvenation through review of recent available data, highlighting controversies and expert insights to guide future studies, and stimulate discourse and innovations benefitting patients.

METHODS

A structured review and expert analysis of PubMed publications before October 2023, with a focus on recent literature from January 2020 through October 2023.

RESULTS AND CONCLUSION

Growing literature supports the utility and benefits of PRP and related autologous products for applications for skin and hair, with strongest evidence for androgenetic alopecia and skin rejuvenation. However, this is limited by lack of consensus regarding best practices and protocols. Randomized, controlled trials with uniform metrics comparing outcomes of various compositions of autologous blood products, preparation methods, dosimetry, and frequency of treatments are still required. This will allow the medical discourse to grow beyond the realm of expert opinion into consensus, standardization, and more wide spread adoption of best practices that will benefit patients.

Association between Platelet-Derived Growth Factor Receptor Alpha Gene Polymorphisms and Platelet-Rich Plasma's Efficiency in Treating Lateral Elbow Tendinopathy-A Prospective Cohort Study

Individual differences in the response to platelet-rich plasma (PRP) therapy can be observed among patients. The genetic background may be the cause of this variability. The current study focused on the impact of genetic variants on the effectiveness of PRP. The aim of the present study was to analyze the impact of single nucleotide polymorphisms (SNP) of the platelet-derived growth factor receptor alpha (PDGFRA) gene on the effectiveness of treating lateral elbow tendinopathy (LET) with PRP. The treatment's efficacy was analyzed over time (2, 4, 8, 12, 24, 52 and 104 weeks after the PRP injection) on 107 patients using patient-reported outcome measures (PROM) and achievement of a minimal clinically important difference (MCID). Four SNPs of the PDGFRA gene (rs7668190, rs6554164, rs869978 and rs1316926) were genotyped using the TaqMan assay method. Patients with the AA genotypes of the rs7668190 and the rs1316926 polymorphisms, as well as carriers of the T allele of rs6554164 showed greater effectiveness of PRP therapy than carriers of other genotypes. Moreover, the studied SNPs influenced the platelets' parameters both in whole blood and in PRP. These results showed that PDGFRA gene polymorphisms affect the effectiveness of PRP treatment. Genotyping the rs6554164 and the rs1316926 SNPs may be considered for use in individualized patient selection for PRP therapy.

The Impact of Blood Morphological Parameters on Treatment Outcomes in Tennis Elbow Patients Receiving Platelet-Rich Plasma (PRP) Therapy: A Prospective Study

Platelet-rich plasma (PRP) therapy holds substantial promise for the treatment of tennis elbow, a complex and challenging musculoskeletal condition. The aim of the study was to assess whether there are correlations between the levels of individual morphotic elements determined in whole blood and the outcomes of tennis elbow treatment with PRP injection, as measured using patient-reported outcome measures (PROMs) such as the Visual Analog Scale (VAS), Quick Disabilities of the Arm, Shoulder, and Hand (QDASH), and Patient-Rated Tennis Elbow Evaluation (PRTEE). A prospective analysis was conducted on 107 patients (132 elbows) undergoing lateral epicondylitis treatment with (PRP) injections. Patients completed VAS, PRTEE, and QDASH questionnaires on the day of PRP administration and at established checkpoints (2, 4, 8, 12, 24, 52, and 104 weeks). Minimal clinically important difference (MCID) was employed to assess the treatment effects. Then, correlations were measured within each PROM, and the impact of the concentration of individual blood parameters on the MCID outcomes was assessed. Analyzing the relationships between the MCID+ and MCID- groups, significant correlations for the VAS and QDASH scales were observed. The level of individual morphotic elements in the blood may have influenced the treatment outcome, as measured using specific patient-reported outcome measures (PROMs). Regarding the VAS scale, factors favoring a positive treatment outcome included higher values of eosinophils (EOS) and basophils (BASO). For the QDASH scale, these factors were a lower value of mean corpuscular volume (MCV) and a higher mean corpuscular hemoglobin (MCH). The levels of certain blood parameters, such as EOS and BASO, in the current study influenced the classification of patients into MCID+ or MCID- groups, based on the VAS and QDASH scales.

Autologous Conditioned Serum Increases Fat Graft Viability More than Platelet-Rich Plasma in a Controlled Rat Model

BACKGROUND

Platelet-rich plasma has been used to support fat graft retention, but it may include inflammatory mediators such as interleukin-1β. Autologous conditioned serum also contains high levels of various anti-inflammatory cytokines. The authors hypothesized that combining autologous conditioned serum with fat graft would increase fat graft survival more than platelet-rich plasma.

METHODS

Twenty-seven adult, male, Sprague-Dawley rats were divided into three groups of nine. Ten nonstudy rats were used to prepare platelet-rich plasma, autologous conditioned serum, and fat grafts. Next, 0.7-ml fat graft with a combination of 0.2 ml of autologous conditioned serum, platelet-rich plasma, or phosphate-buffered saline was applied to their dorsa. Fat graft volume was assessed on postoperative day 2 and on the day of euthanization at 1, 3, and 5 months postoperatively. Histopathologic analysis was performed to measure integrity, inflammation, fibrosis, and vascularization.

RESULTS

The median volume percentages and interquartile ranges at 1 month postoperatively were 97.3 percent (77.3 to 119.6 percent), 40.4 percent (30.9 to 46.9 percent), and 72.1 percent (53.6 to 84.9 percent) in autologous conditioned serum plus fat graft, phosphate-buffered saline plus fat graft, and platelet-rich plasma plus fat graft, respectively (p < 0.05); at 3 months postoperatively, values were 82.3 percent (70.3 to 88.3 percent), 36.6 percent (29.4 to 43.1 percent), and 48.3 percent (31.4 to 57.9 percent) (p < 0.001); and at 5 months postoperatively, values had increased to 83.9 percent (58.3 to 102.4 percent), 40.3 percent (20.1 to 50.6 percent), and 56.3 percent (37.7 to 74.9 percent), respectively (p < 0.05).

CONCLUSIONS

Autologous conditioned serum and platelet-rich plasma improved fat graft outcomes compared to saline, whereas autologous conditioned serum was associated with less inflammation, greater fat viability, and more integrity.

CLINICAL RELEVANCE STATEMENT

Combining fat graft with autologous conditioned serum may be a better option to minimize resorption rate and improve graft survival.

Autologous Biological Vitamin-C-added (ABC) Filler for Facial Volume Restoration

PURPOSE

Face rejuvenation procedures with injectable agents continue to gain popularity. Nowadays, a variety of commercial products are available as filler material. Ideal fillers should be inexpensive, easily obtainable, nontoxic, and biocompatible. The aim of this study is to report a clinical perspective for an appropriate, feasible, and inexpensive protocol of a stable, autologous biological filler for facial volume restoring without any commercial kits.

METHODS

Eight patients were investigated who underwent facial injection with ABC filler. Eleven ml of whole blood was placed in standard tubes containing anticoagulant and for each patient, 8 tubes were prepared. After the centrifugation at 1630 xg for 5 minutes, the upper plasma was taken, calcium was added and cooled. After the addition of vitamin C, the syringes were incubated at 85 °C for 10 minutes. The autologous biological material obtained was used as filling material. For comparison, FACE-Q satisfaction questionnaires were used before and after the procedure.

RESULTS

All patients were followed up for a minimum of 4 months. No major complications were recorded. The patient-reported FACE-Q satisfaction and FACE-Q quality of life pre- and post-procedure results showed statistically significant improvement (p  <  0.05). Overall satisfaction with the outcome was 89.12 ± 16.73 (range 55-100).

CONCLUSIONS

ABC filler can be seen as a reliable, inexpensive, and easily obtainable material to restore facial volume with increased patient satisfaction and quality of life scores. We believe that our study will be encouraging to the application of autologous biological fillers for further clinical and scientific studies.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Enrichment of leukocytes in peripheral blood using 3D printed tubes

Leukocytes have an essential role in patient clinical trajectories and progression. Traditional methods of leukocyte enrichment have many significant limitations for current applications. It is demonstrated a novel 3D printing leukocyte sorting accumulator that combines with centrifugation to ensure label-free initial leukocyte enrichment based on cell density and size. The internal structure of leukocyte sorting accumulator (revealed here in a new design, leukocyte sorting accumulator-3, upgraded from earlier models), optimizes localization of the buffy coat fraction and the length of the period allocated for a second centrifugation step to deliver a higher recovery of buffy coats than earlier models. Established methodological parameters were evaluated for reliability by calculating leukocyte recovery rates and erythrocyte depletion rates by both pushing and pulling methods of cell displacement. Results indicate that leukocyte sorting accumulator-3 achieves a mean leukocytes recovery fraction of 96.2 ± 2.38% by the pushing method of layer displacement. By the pulling method, the leukocyte sorting accumulator-3 yield a mean leukocytes recovery fraction of 94.4 ± 0.8%. New procedures for preliminary enrichment of leukocytes from peripheral blood that avoid cellular damage, as well as avert metabolic and phase cycle intervention, are required as the first step in many modern clinical and basic research assays.

A cross-sectional analysis of the effects of various centrifugation speeds and inclusion of the buffy coat in platelet-rich plasma preparation

INTRODUCTION

Platelet-rich plasma is an autologous blood preparation which is used in various medical specialties because of its regenerative properties. There is a wide variation in platelet-rich plasma preparation protocols and attaining the ideal platelet yield (>1 million platelets/μL) in a clinic setting can be challenging. We aimed at analyzing the centrifuge spin rates at which to attain an ideal platelet-rich plasma yield and also to study the effect of inclusion of the buffy coat after the first spin on the final platelet concentration in platelet-rich plasma.

METHODS

Seventy-five whole blood samples were obtained and divided into two groups - (1) leukocyte-rich platelet-rich plasma group and (2) leukocyte-poor platelet-rich plasma group. Samples in both groups were centrifuged using the dual spin method, at one of three centrifugation speed combinations (initial "soft" spin and second "hard" spin speeds, respectively): (1) 100 g/400 g, (2) 350 g/1350 g and (3) 900 g/1800 g. Platelet, red blood cell (RBC) and white blood cell (WBC) counts in both groups were compared.

RESULTS

The 100 g/400 g spin gave a high platelet yield (increase of 395.4 ± 111.1%) in the leukocyte-poor-platelet-rich plasma group, while in the leukocyte-rich platelet-rich plasma group both 100 g/400 g and 350 g/1350 g spins resulted in significantly higher yields with an increase of 691.5 ± 316.3% and 738.6 ± 193.3%, respectively.

LIMITATIONS

The study was limited by a smaller sample size in the pure platelet-rich plasma (leukocyte-poor platelet-rich plasma) group.

CONCLUSION

Ideal platelet yields can be achieved with both the 100 g/400 g as well as the 350 g/1350 g spins using the buffy coat inclusion method while the 100 g/400 g spin for "pure" platelet-rich plasma accomplishes a near-ideal platelet count with significantly reduced contamination with other cells.

Monitoring Response to Platelet-Rich Plasma in Patients with Alopecia Areata with Optical Coherence Tomography: A Case Series

Alopecia areata (AA) is an autoimmune hair loss condition that is difficult to treat and frequently disruptive to the psychosocial well-being of patients. Platelet-rich plasma (PRP) is an innovative therapy that provides concentrated GFs that impart anti-inflammatory effects. Optical coherence tomography (OCT) is a noninvasive imaging modality with the potential for providing quantitative monitoring of AA response to PRP. Our objective is to share our experience using OCT to monitor the therapeutic progress of patients with AA treated with PRP. Two patients with patchy AA and one with alopecia universalis were treated with PRP three times at 6-week intervals as part of a larger clinical trial. Patients were followed from baseline to week 24 with OCT imaging. OCT demonstrates an increase in hair density associated with improvement in inflammation at week 24. Conversely, the patient with alopecia universalis did not experience any significant change in follicular activity. This case series exemplifies the potential of PRP in inflammatory regulation as well as hair regrowth in patchy AA, whereas there is no notable advantage in alopecia universalis. Our findings add evidence on the possible value of OCT in quantitatively assessing hair growth progress throughout a treatment course.

Leucocyte-Rich Platelet-Rich Plasma Enhances Fibroblast and Extracellular Matrix Activity: Implications in Wound Healing

Background: Platelet-rich plasma (PRP) is an autologous blood product that contains a high concentration of platelets and leucocytes, which are fundamental fibroblast proliferation agents. Literature has emerged that offers contradictory findings about leucocytes within PRP. Herein, we elucidated the effects of highly concentrated leucocytes and platelets on human fibroblasts. Methods: Leucocyte-rich, PRP (LR-PRP) and leucocyte-poor, platelet-poor plasma (LP-PPP) were compared to identify their effects on human fibroblasts, including cell proliferation, wound healing and extracellular matrix and adhesion molecule gene expressions. Results: The LR-PRP exhibited 1422.00 ± 317.21 × 10³ platelets/µL and 16.36 ± 2.08 × 10³ white blood cells/µL whilst the LP-PPP demonstrated lower concentrations of 55.33 ± 10.13 × 10³ platelets/µL and 0.8 ± 0.02 × 10³ white blood cells/µL. LR-PRP enhanced fibroblast cell proliferation and cell migration, and demonstrated either upregulation or down-regulation gene expression profile of the extracellular matrix and adhesion molecules. Conclusion: LR-PRP has a continuous stimulatory anabolic and ergogenic effect on human fibroblast cells.

Platelet-rich plasma for the treatment of knee osteoarthritis: an expert opinion and proposal for a novel classification and coding system

INTRODUCTION

Platelet-rich plasma (PRP) is able to modulate the joint environment by reducing the inflammatory distress and promoting tissue anabolism. Therefore, it has gained increasing popularity among clinicians in the treatment of osteoarthritis (OA), and it is currently proposed beside consolidated options such as viscosupplementation.

AREAS COVERED

A systematic review of all available meta-analyses evaluating intra-articular PRP injections in patients affected by knee OA was performed, to understand how this biologic treatment approach compares to the traditional injective therapies available in clinical practice. Moreover, a novel coding system and 'minimum reporting requirements' are proposed to improve future research in this field and promote a better understanding of the mechanisms of action and indications.

EXPERT OPINION

The main limitation in the current literature is the extreme variability of PRP products used, with often paucity or even lack of data on the biologic features of PRP, which should not be considered as a simple substance, but rather a 'procedure' requiring accurate reporting of the characteristics of the product but also all preparation and application modalities. This approach will aid in matching the optimal PRP product to specific patient factors, leading to improved outcomes and the elucidation of the cost-effectiveness of this treatment.

The Impact of Duration and Force of Centrifugation on Platelet Content and Mass in the Preparation of Platelet-Rich Plasma

PURPOSE

Platelet-rich plasma (PRP) is an autologous prepared plasma enriched with platelets and obtained after a centrifugal separation and aggregation procedure. However, the optimized preparation protocol for PRP is still controversial and there are no standardized preparation protocols. The aim of this study is to show the effect of time and force of the centrifugation on the concentrations of platelets and to optimize the effective PRP preparation protocol.

METHODS

For the study, whole blood was drawn into 24 different 6-ml standard tubes containing 0.6 ml anticoagulant citrate dextrose solution-formula A. The samples were centrifuged separately at forces of 45×g, 180×g, 400×g, 725×g, 1130×g and 1630×g for 5, 10, 15 and 20 min. Every sample was analyzed, and a comparison was made between all groups.

RESULTS

No significant difference was observed in terms of platelet concentration, mean platelet volume or platelet mass between all groups (p > 0.05). The mean ± SD of platelet mass in baseline is 1890 ± 134 × 10³ fL/μL. The mean ± SD of platelet mass in the high centrifugal force of 1630×g was 3395 ± 564 × 10³ fL/μL, 2638 ± 425 × 10³ fL/μL, 2355 ± 449 × 10³ fL/μL and 2109 ± 41 × 10³ fL/μL over times of 5, 10, 15 and 20 min, respectively. The mean ± SD of platelet mass in the low centrifugal force of 45×g was 2002 ± 1623 × 10³ fL/μL, 2491 ± 1591 × 10³ fL/μL, 2611 ± 876 × 10³ fL/μL and 3003 ± 511 × 10³/μL over times of 5, 10, 15 and 20 min, respectively.

CONCLUSIONS

Platelets should be evaluated with platelet mass not including platelet concentrations alone, but also with mean platelet volume, which symbolizes the size of platelets while comparing platelet-rich plasma preparation protocols and kits. This could be a new starting point for comparison of PRP for all applications in the literature. All centrifugation forces and times could produce biologically reactive PRP. It may be only suggested that if high acceleration force is used, low durations should be selected, or if low acceleration force is used, long time of centrifugation should be selected.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Autologous Platelet-Rich Plasma (CuteCell PRP) Safely Boosts In Vitro Human Fibroblast Expansion

Nowadays autologous fibroblast application for skin repair presents an important clinical interest. In most cases, in vitro skin cell culture is mandatory. However, cell expansion using xenogeneic or allogenic culture media presents some disadvantages, such as the risk of infection transmission or slow cell expansion. In this study, we investigated an autologous culture system to expand human skin fibroblast cells in vitro with the patient's own platelet-rich plasma (PRP). Human dermal fibroblasts were isolated from patients undergoing abdominoplasty, and blood was collected to prepare nonactivated PRP using the CuteCell™ PRP medical device. Cultures were followed up to 7 days using a medium supplemented with either fetal bovine serum (FBS) or PRP. Fibroblasts cultured in medium supplemented with PRP showed dose-dependently significantly higher proliferation rates (up to 7.7 times with 20% of PRP) and initiated a faster migration in the in vitro wound healing assay compared with FBS, while chromosomal stability was maintained. At high concentrations, PRP changed fibroblast morphology, inducing cytoskeleton rearrangement and an increase of alpha-smooth muscle actin and vimentin expression. Our findings show that autologous PRP is an efficient and cost-effective supplement for fibroblast culture, and should be considered as a safe alternative to xenogeneic/allogenic blood derivatives for in vitro cell expansion. Impact Statement Autologous dermal fibroblast graft is an important therapy in skin defect repair, but in vitro skin cell culture is mandatory in most cases. However, cell expansion using xenogeneic/allogenic culture media presents some disadvantages, such as the risk of infection transmission. We demonstrated that an autologous culture system with the patient's own platelet-rich plasma is an efficient, cost-effective, and safe supplement for fibroblast culture. As it respects the good manufacturing practices and regulatory agencies standards, it should be considered as a potent alternative and substitute to xenogeneic or allogenic blood derivatives for the validation of future clinical protocols using in vitro cell expansion.

Platelet-rich plasma lyophilization enables growth factor preservation and functionality when compared with fresh platelet-rich plasma

Aims: To compare levels and activity of the growth factors between fresh and lyophilized platelet-rich plasma (PRP). Methods: Analysis of platelet concentration using fibroblast and human umbilical vein endothelial cell cultures were compared between fresh and lyophilized PRP obtained from peripheral blood. Results: After lyophilization, 54% of platelets were intact whereas the fresh showed no aggregation with agonists (levels under 20%). The concentration of growth factors (VEGF, EGF, TGF-β and PDGF) in both products were similar. Fresh and lyophilized PRPs induced proliferation in the fibroblasts at 24 h (0.303 vs 0.300, respectively). Conclusion: Lyophilized PRP appears to be an alternative to fresh PRP and the results evidenced the role of growth factors as a key element in the activity of this product.