Evaluation of platelet-rich plasma from diabetic donors shows increased platelet vascular endothelial growth factor release

Biological processes and factors involved in soft and hard tissue healing

Wound healing is a complex and iterative process involving myriad cellular and biologic processes that are highly regulated to allow satisfactory repair and regeneration of damaged tissues. This review is intended to be an introductory chapter in a volume focusing on the use of platelet concentrates for tissue regeneration. In order to fully appreciate the clinical utility of these preparations, a sound understanding of the processes and factors involved in soft and hard tissue healing. This encompasses an appreciation of the cellular and biological mediators of both soft and hard tissues in general as well as specific consideration of the periodontal tissues. In light of good advances in this basic knowledge, there have been improvements in clinical strategies and therapeutic management of wound repair and regeneration. The use of platelet concentrates for tissue regeneration offers one such strategy and is based on the principles of cellular and biologic principles of wound repair discussed in this review.

The Impact of Lower Limb Immobilization and Rehabilitation on Angiogenic Proteins and Capillarization in Skeletal Muscle

PURPOSE

Skeletal muscle vascularization is important for tissue regeneration after injury and immobilization. We examined whether complete immobilization influences capillarization and oxygen delivery to the muscle and assessed the efficacy of rehabilitation by aerobic exercise training.

METHODS

Young healthy males had one leg immobilized for 14 d and subsequently completed 4 wk of intense aerobic exercise training. Biopsies were obtained from musculus vastus lateralis, and arteriovenous blood sampling for assessment of oxygen extraction and leg blood flow during exercise was done before and after immobilization and training. Muscle capillarization, muscle and platelet content of vascular endothelial growth factor (VEGF), and muscle thrombospondin-1 were determined.

RESULTS

Immobilization did not have a significant impact on capillary per fiber ratio or capillary density. The content of VEGF protein in muscle samples was reduced by 36% (P = 0.024), and VEGF to thrombospondin-1 ratio was 94% lower (P = 0.046). The subsequent 4-wk training period increased the muscle VEGF content and normalized the muscle VEGF to thrombospondin-1 ratio but did not influence capillarization. Platelet VEGF content followed the trend of muscle VEGF. At the functional level, oxygen extraction, blood flow, and oxygen delivery at rest and during submaximal exercise were not affected by immobilization or training.

CONCLUSIONS

The results demonstrate that just 2 wk of leg immobilization leads to a strongly reduced angiogenic potential as evidenced by reduced muscle and platelet VEGF content and a reduced muscle VEGF to thrombospondin-1 ratio. Moreover, a subsequent period of intensive aerobic exercise training fails to increase capillarization in the previously immobilized leg, possibly because of the angiostatic condition caused by immobilization.

Phase I/II Clinical Trial of Autologous Activated Platelet-Rich Plasma (aaPRP) in the Treatment of Severe Coronavirus Disease 2019 (COVID-19) Patients

Background

The outbreak of Coronavirus Disease 2019 (COVID-19) has been increasing rapidly. This disease causes an increase in proinflammatory cytokine production that leads to cytokine storm or cytokine release syndrome (CRS). Autologous activated platelet-rich plasma (aaPRP) contains various types of growth factors and anti-inflammatory cytokines that may have the potential to suppress CRS. This study of phase I/II trial was aimed to evaluate the safety and efficacy of aaPRP to treat severe COVID-19 patients.

Methods

A total of 10 severe COVID-19 patients from Koja Regional Public Hospital (Koja RPH) were admitted to the intensive care unit (ICU). All patients received aaPRP administration three times. Primary outcomes involving the duration of hospitalization, oxygen needs, time of recovery, and mortality were observed. Secondary outcomes involving C-reactive protein (CRP), neutrophil, lymphocyte, and lymphocyte-to-CRP (LCR) and neutrophil-lymphocyte ratio (NLR) were analyzed.

Results

All patients were transferred to the ICU with a median duration of 9 days. All patients received oxygen at enrollment and nine of ten patients recovered from the ICU and transferred to the ward room. There was one patient who passed away in the ICU due to heart failure. The results of secondary outcomes showed that CRP value and lymphocytes counts were significantly decreased while neutrophils, LCR, and NLR were slightly increased after aaPRP administration.

Conclusions

Our results of the phase I/II trial demonstrated that the use of aaPRP in severe COVID-19 patients was safe and not associated with serious adverse events, which showed that aaPRP was a promising adjunctive therapy for severe COVID-19 patients.

A High Activity Level Is Required for Augmented Muscle Capillarization in Older Women

PURPOSE

This study aimed to evaluate the influence of lifelong regular physical activity on skeletal muscle capillarization in women.

METHODS

Postmenopausal women, 61±4 yr old, were divided according to self-reported physical activity level over the past 20 yrs: sedentary (SED; n = 14), moderately active (MOD; n = 12), and very active (VERY; n = 15). Leg blood flow (LBF) was determined by ultrasound Doppler, and blood samples were drawn from the femoral artery and vein for calculation of leg oxygen uptake (LVO2) at rest and during one-legged knee extensor exercise. A skeletal muscle biopsy was obtained from the vastus lateralis and analyzed for capillarization and vascular endothelial growth factor (VEGF) and mitochondrial OXPHOS proteins. Platelets were isolated from venous blood and analyzed for VEGF content and effect on endothelial cell proliferation.

RESULTS

The exercise-induced rise in LBF and LVO2 was faster (P = 0.008) in VERY compared with SED and MOD. Steady-state LBF and LVO2 were lower (P < 0.04) in MOD and VERY compared with SED. Capillary-fiber ratio and capillary density were greater (P < 0.03) in VERY (1.65 ± 0.48 and 409.3 ± 57.5) compared with MOD (1.30 ± 0.19 and 365.0 ± 40.2) and SED (1.30 ± 0.30 and 356.2 ± 66.3). Skeletal muscle VEGF and OXPHOS complexes I, II, and V were ~1.6-fold and ~1.25-fold (P < 0.01) higher, respectively, in VERY compared with SED. Platelets from all groups induced an approximately nine-fold (P < 0.001) increase in endothelial cell proliferation.

CONCLUSION

A very active lifestyle is associated with superior skeletal muscle exercise hemodynamics and greater potential for oxygen extraction concurrent with a higher skeletal muscle capillarization and mitochondrial capacity.

The Effect of Intravenous Autologous Activated Platelet-Rich Plasma Therapy on "Profibrotic Cytokine" IL-1β Levels in Severe and Critical COVID-19 Patients: A Preliminary Study

INTRODUCTION

Elevated concentration of proinflammatory cytokines followed by hyperinflammation is one of the hallmarks of severe and critical COVID-19. In the short term, this may result in ARDS and lung injury; subsequently, this may cause pulmonary fibrosis-a disease with poor prognosis-in the long run. Among the cytokines, interleukin-1β (IL-1β) is one of the most overexpressed in COVID-19. We speculate that administration of intravenous activated autologous platelet-rich plasma (aaPRP), which contains interleukin-1 receptor antagonist (IL-1RA), would lower IL-1β levels and benefit the severe and critical COVID-19 patients.

METHODS

After acquiring ethical clearance, we recruited 12 adult COVID-19 patients of both sexes from the Koja Regional Hospital (Jakarta, Indonesia) ICU. After selection, seven patients were included and divided into two groups, severe and critical. In addition to three doses of aaPRP, both groups received the same treatment of antiviral, steroid, and antibiotics. Quantification of plasma IL-1β levels was performed by beads multiplex assay a day before the first aaPRP administration and a day after the second and third aaPRP administration. PaO₂/FiO₂ ratio and lung injury scores were evaluated a day before and a day after each aaPRP administration.

RESULTS

Severe and critical patients' initial plasma IL-1β concentration was 4.71 pg/mL and 3.095 pg/mL, respectively. After 2 treatments with aaPRP, severe patients' plasma IL-1β concentration decreased 12.48 pg/mL, while critical patients' plasma IL-1β concentration increased to 18.77 pg/mL. Furthermore, after 3 aaPRP treatments, significant amelioration of patients' PaO₂/FiO₂ ratio from 71.33 mmHg at baseline to 144.97 mmHg was observed (p < 0.05). However, no significant improvement in lung injury score was observed in severe and critical groups. All severe patients and one critical patient recovered.

CONCLUSION

The use of aaPRP may prevent pulmonary fibrosis in severe COVID-19 patients through the reduction of patients' plasma IL-1β concentration and the amelioration of PaO₂/FiO₂ ratio.

The application of platelet-rich plasma for skin graft enrichment: A meta-analysis

Existing evidence demonstrated that the role of platelet-rich plasma (PRP) in skin graft enrichment is uncertain. The aim of this study was to evaluate the efficacy and safety of PRP for skin graft. PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for randomised controlled trials that compared outcomes of skin graft treated with PRP versus those treated with blank controls. The outcomes mainly included the rate of skin graft take, number of skin graft loss and haematoma formation, and complications. There were 11 studies involving a total of 910 cases of skin grafts. Compared with the control group, PRP group had a significantly higher rate of skin graft take (mean difference = 5.47%; 95% confidence interval [CI], 2.80%-8.14%; P < .0001), fewer number of skin graft loss (risk ratio [RR] = 0.26; 95% CI, 0.13-0.55; P = .0004) and fewer cases of haematoma formation (RR = 0.24; 95% CI, 0.11-0.54; P = .0006). There was no significant difference in the incidence of complications between two groups. This meta-analysis summarises current evidence and indicates that PRP is a safe and effective adjuvant for skin graft enrichment.

Safety of Technique and Procedure of Stromal Vascular Fraction Therapy: From Liposuction to Cell Administration

BACKGROUND

Stromal vascular fraction (SVF) therapy has been performed over the past six years to treat 421 patients by our group in five clinical centers. Autologous SVF, which is a substance containing stem cells, was isolated from lipoaspirate, mixed with platelet-rich plasma (PRP), and administered to patients with degenerative diseases, autoimmune diseases, trauma, aging, and other diseases with unknown etiology. This study aimed to determine the safety of SVF and PRP that were given through infusion, spinal, and intra-articular injection.

METHODS

The lipoaspirate was treated with a tissue-dissociating enzyme, and then, through centrifugation, SVF was isolated. In addition, blood was drawn from each patient, and PRP was isolated. Autologous PRP and SVF were administered to all subjects by intravenous (IV) injection. A minority group within the population received an additional spinal or intra-articular injection. The type of intervention was determined by each disease evaluation. The cell doses and adverse events for each patient were documented and analyzed.

RESULTS

Cell dose that was considered to be safe was less than 10 billion SVF cells in 250 cc of normal saline, for IV injection, and less than 1 billion SVF, for intra-articular and spinal injection. Adverse events were not severe and were treated successfully. Any observed adverse events were identified as a result of spinal or intra-articular injections and were not related to SVF or PRP.

CONCLUSIONS

Our results showed that administration of high dose of SVF until 10 billion cells in a majority of 421 patients through infusion, spinal, and intra-articular injection was feasible without causing major adverse events and should be further investigated in well-designed phase I-II clinical trial to address the safety and efficacy of therapy.

Platelet-rich plasma counteracts detrimental effect of high-glucose concentrations on mesenchymal stem cells from Bichat fat pad

Diabetic patients display increased risk of periodontitis and failure in bone augmentation procedures. Mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) represent a relevant advantage in tissue repair process and regenerative medicine. We isolated MSCs from Bichat's buccal fat pad (BFP) and measured the effects of glucose and PRP on cell number and osteogenic differentiation potential. Cells were cultured in the presence of 5.5-mM glucose (low glucose [LG]) or 25-mM glucose (high glucose [HG]). BFP-MSC number was significantly lower when cells were cultured in HG compared with those in LG. Following osteogenic differentiation procedures, calcium accumulation, alkaline phosphatase activity, and expression of osteogenic markers were significantly lower in HG compared with LG. Exposure of BFP-MSC to PRP significantly increased cell number and osteogenic differentiation potential, reaching comparable levels in LG and in HG. Thus, high-glucose concentrations impair BFP-MSC growth and osteogenic differentiation. However, these detrimental effects are largely counteracted by PRP.