Immunoregulatory role of platelet derivatives in the macrophage-mediated immune response

Background

Macrophages are innate immune cells that display remarkable phenotypic heterogeneity and functional plasticity. Due to their involvement in the pathogenesis of several human conditions, macrophages are considered to be an attractive therapeutic target. In line with this, platelet derivatives have been successfully applied in many medical fields and as active participants in innate immunity, cooperation between platelets and macrophages is essential. In this context, the aim of this review is to compile the current evidence regarding the effects of platelet derivatives on the phenotype and functions of macrophages to identify the advantages and shortcomings for feasible future clinical applications.

Methods

A total of 669 articles were identified during the systematic literature search performed in PubMed and Web of Science databases.

Results

A total of 27 articles met the inclusion criteria. Based on published findings, platelet derivatives may play an important role in inducing a dynamic M1/M2 balance and promoting a timely M1-M2 shift. However, the differences in procedures regarding platelet derivatives and macrophages polarization and the occasional lack of information, makes reproducibility and comparison of results extremely challenging. Furthermore, understanding the differences between human macrophages and those derived from animal models, and taking into account the peculiarities of tissue resident macrophages and their ontogeny seem essential for the design of new therapeutic strategies.

Conclusion

Research on the combination of macrophages and platelet derivatives provides relevant information on the function and mechanisms of the immune response.

The effectiveness of autologous platelet concentrates in prevention and treatment of medication-related osteonecrosis of the jaws: A systematic review

The systematic review aims to answer the PICOS question: "Are the autologous platelet concentrates (APCs) an effective strategy in prevention and/or treatment of patients at risk of/affected by medication-related osteonecrosis of the jaws (MRONJ)?". A literature search was conducted via PubMed, MEDLINE, EMBASE, and CINAHL (January 2006 - September 2023). 30 articles were included, evaluating preventive (n = 8*) and treatment strategies (n = 23*). The risk of bias and quality of studies were assessed utilising ROB-2, ROBIN-1 and GRADE criteria. Meta-analysis was undertaken for eligible studies. The application of APCs demonstrated a statistically significant effectiveness in prevention of MRONJ in 86.13% (p < 0.001) but failed to achieve the same level of certainty in treatment of established MRONJ in 83.4% (p = 0.08). High levels of bias were identified; thus, the results should be interpreted with caution. More high quality prospective randomised controlled trials are needed to further evaluate the effectiveness of APCs in management of MRONJ.

Tooth autotransplantation outcomes using platelet-rich fibrin: A promising approach; case study

BACKGROUND

Autogenous tooth transplantation refers to a surgical procedure involving the relocation of a tooth within the same individual. Incorporating platelet-rich fibrin (PRF) in this procedure holds the potential to improve healing, accelerate recovery, and optimize treatment outcomes.

METHODS

In this article, the authors illustrate a PRF-based approach for autogenous tooth transplantation through two case scenarios. These cases outline the surgical steps of tooth transplantation and demonstrate the potential role of PRF in enhancing soft tissue healing. Furthermore, the article provides insights from a long-term follow-up spanning over 7 years.

RESULTS

Tooth transplantation in young adults is promising but depends on factors such as root development stage and donor tooth size matching. Including PRF may improve healing, at least in the short term, due to its rich concentration of growth factors and cytokines, promoting effective tissue regeneration.

CONCLUSIONS

Autogenous tooth transplantation has shown to be a viable treatment option for replacing the missing dentition. Adding PRF to the autogenous tooth transplantation procedure may speed up and enhance the treatment outcome. While the favorable results of these cases might be partially attributed to the use of PRF, the contribution of PRF to the healing process of tooth transplant remains conjectural and requires validation through additional research.

KEY POINTS/HIGHLIGHTS

Tooth autotransplantation can be performed in younger patients without requiring root canal treatment, while also potentially benefiting from the incorporation of platelet-rich fibrin (PRF).

Bioactive Scaffolds as a Promising Alternative for Enhancing Critical-Size Bone Defect Regeneration in the Craniomaxillofacial Region

Reconstruction of critical-size bone defects (CSDs) in the craniomaxillofacial (CMF) region remains challenging. Scaffold-based bone-engineered constructs have been proposed as an alternative to the classical treatments made with autografts and allografts. Scaffolds, a key component of engineered constructs, have been traditionally viewed as biologically passive temporary replacements of deficient bone lacking intrinsic cues to promote osteogenesis. Nowadays, scaffolds are functionalized, giving rise to bioactive scaffolds promoting bone regeneration more effectively than conventional counterparts. This review focuses on the three approaches most used to bioactivate scaffolds: (1) conferring microarchitectural designs or surface nanotopography; (2) loading bioactive molecules; and (3) seeding stem cells on scaffolds, providing relevant examples of in vivo (preclinical and clinical) studies where these methods are employed to enhance CSDs healing in the CMF region. From these, adding bioactive molecules (specifically bone morphogenetic proteins or BMPs) to scaffolds has been the most explored to bioactivate scaffolds. Nevertheless, the downsides of grafting BMP-loaded scaffolds in patients have limited its successful translation into clinics. Despite these drawbacks, scaffolds containing safer, cheaper, and more effective bioactive molecules, combined with stem cells and topographical cues, remain a promising alternative for clinical use to treat CSDs in the CMF complex replacing autografts and allografts.

Reinforcement of colon anastomosis healing with leukocyte platelet-rich fibrin in rabbit model

AIM

This study investigated the regenerative efficacy of leukocyte platelet-rich fibrin (L-PRF) on colon anastomotic healing in rabbits.

MAIN METHODS

Thirty-six healthy male white New Zealand rabbits were subjected to complete transactions of the ascending colon. The rabbits were equally divided into two groups: the control group, where the transected colon ends were anastomosed by a simple interrupted suture pattern, and the L-PRF-treated group, in which L-PRF was wrapped entirely around the anastomotic line. The postoperative acute pain scale was assessed using the Bristol Rabbit Pain Scale before surgery and at each four-hour interval post-operatively. After euthanizing the rabbits, the adhesion degree score, anastomotic bursting pressure, and stenosis degree of the anastomotic colon were assessed, and histopathological examination at the 7th, 14th, and 28th days postoperatively.

KEY FINDINGS

Rabbits in both groups showed a significant increase in pain scores compared to baseline. Postoperatively, the L-PRF group exhibited significantly lower pain scores, adhesion scores, and stenosis degrees than the control group. However, the anastomotic bursting pressure was significantly higher in the L-PRF group. Re-epithelialization, polymorphonuclear neutrophil infiltration, granulation tissue formation, and collagen deposition scores were improved considerably in the L-PRF group compared to the control group. Immunostaining of growth factor expression was significantly lower in the control than in the L-PRF group.

SIGNIFICANCE

The L-PRF can augment collagen deposition, re-epithelialize the mucosa, promote angiogenesis, reduce adhesions, and diminish the stenosis degree scores. Therefore, it can be considered a promising aid in healing bowel anastomoses.

Effect of platelet concentrates for pain and symptom management in oral lichen planus: an evidence-based systematic review

BACKGROUND

Platelet Concentrate (PC) injection therapy has shown potential as a local therapy for oral lichen planus (OLP). However, its safety and efficacy have not yet been fully established. Our research compared the efficacy of PC with topical steroid treatment in alleviating pain and symptoms related to OLP. We aims to present evidence-based alternatives that dentists can use to improve patient outcomes while reducing potential side effects.

METHODS

We conducted a systematic search of five electronic databases up to April 2023, including Embase, Cochrane Central Register of Controlled Trials, PubMed, OVID Medline, and WanFang, to evaluate PCs' efficacy compared to topical corticosteroid therapy for OLP. The literature quality was assessed using the Cochrane ROB tool. A fixed-effects model was used to determine the Weighted Mean Difference (WMD) and Mean Difference (MD) at a 95% confidence interval (CI) for pain severity and other relevant clinical indicators.

RESULTS

The comparison between topical corticosteroid therapy and PCs showed no significant difference for pain relief (WMD = -0.07, CI = 95% -0.34 to 0.19), symptom improvement (MD = -0.21, CI = 95% -0.55 to 0.13), or the severity of included lesions measured by REU scores (MD = -0.25, CI = 95% -0.32 to 0.82).

CONCLUSIONS

Locally injected PC have been found efficient in managing oral lichen planus, indicating that they are a promising alternative option to steroid therapy for OLP patients, particularly those who have not responded favorably to steroid therapy. However, further research is needed to establish determining the recurrence rate and long-term adverse effects.

TRIAL REGISTRATION

The systematic review protocol has been registered in advance with the PROSPERO database (CRD42023415372).

Efficacy of Platelet-rich Fibrin in the Treatment and Rehabilitation of Patients with Peri-implant Mucositis

Aim: To evaluate the effectiveness of injectable platelet-rich fibrin (i-PRF) in the complex treatment and rehabilitation of patients with peri-implant mucositis. Materials and Methods: Clinical examination and treatment of 23 patients with peri-implant mucositis were carried out. Patients of the main group (n=11) were injected with liquid platelets-rich fibrin. In patients of the control group (n=12) the treatment protocol involved local antibacterial and anti-inflammatory therapy. The assessment of peri-implant tissues condition was performed on the basis of visual inspection, generally accepted instrumental and X-ray examination and was based on the data of periodontal tests and indexes. Results: In 72.7% of patients after i-PRF usage, reduction of inflammation was observed on the 3rd day of treatment; on the 7th day the clinical status corresponded to the norm. At the same time, in the control group a decrease of inflammation signs was revealed only in 33.3% of patients on the 3rd day and in 66.7% on the 7th day; complete elimination of inflammation in all patients was registered on the 14th day of observation. In 12-month follow-up examination the positive dynamic of peri-implant mucositis treatment was maintained in 81.8% of patients of the main group and in 50.0% of patients of the control group. Conclusions: The use of i-PRF in the complex treatment of peri-implant mucositis contributes to the rapid elimination of inflammation signs and bleeding of the gums surround the implants, accelerates the soft tissues regeneration, shortens treatment times and provides long lasting stabilization of the process.

Effectiveness of platelet rich fibrin versus demineralized bone xenograft in periodontally accelerated osteogenic orthodontics: A pilot comparative clinical study

OBJECTIVES

To compare the rate of extraction space closure between periodontally accelerated osteogenic orthodontics (PAOO) using platelet-rich fibrin (PRF) (Group 1) and PAOO using demineralized bone xenograft (DMBM) (Group 2) and to compare the level of wound healing between the PRF group vs the DMBM group after PAOO.

MATERIALS AND METHODS

A two-arm prospective single blind pilot study with a split-mouth design was used in which 14 patients requiring premolar extraction were divided into two groups: PRF and DMBM. En-masse space closure was carried out with using mini implants after the PAOO procedure. The amount of space closure was measured at five time points with 2-week intervals within 2 months. The gingival healing levels were assessed using early wound healing scores on the first postoperative day.

RESULTS

The rate of extraction space closure was faster in the experimental quadrant at all time points (T1-T4) in the PRF group and at time points (T3, T4) in the DMBM group. Comparison between experimental quadrants showed a significant increase in the rate of space closure in the PRF group T1 to T3 (P < .05). The PRF group showed higher total early healing scores than the DMBM group.

CONCLUSIONS

PRF, when used in the PAOO procedure, produces a faster rate of space closure with better early wound healing than DMBM.