Local delivery of platelet-derived factors mitigates ischemia and preserves ovarian function through angiogenic modulation: A personalized regenerative strategy for fertility preservation.

As the most prominent and ideal modality in female fertility preservation, ovarian tissue cryopreservation, and transplantation often confront the challenge of ischemic damage and follicular loss from avascular transplantation. To surmount this impediment, we engineered a novel platelet-derived factors-encapsulated fibrin hydrogel (PFH), a paradigmatic biomaterial. PFH encapsulates autologous platelet-derived factors, utilizing the physiological blood coagulation cascade for precise local delivery of bioactive molecules. In our study, PFH markedly bolstered the success of avascular ovarian tissue transplantation. Notably, the quantity and quality of follicles were preserved with improved neovascularization, accompanied by decreased DNA damage, increased ovulation, and superior embryonic development rates under a Low-concentration Platelet-rich plasma-derived factors encapsulated fibrin hydrogel (L-PFH) regimen. At a stabilized point of tissue engraftment, gene expression analysis mirrored normal ovarian tissue profiles, underscoring the effectiveness of L-PFH in mitigating the initial ischemic insult. This autologous blood-derived biomaterial, inspired by nature, capitalizes on the blood coagulation cascade, and combines biodegradability, biocompatibility, safety, and cost-effectiveness. The adjustable properties of this biomaterial, even in injectable form, extend its potential applications into the broader realm of personalized regenerative medicine. PFH emerges as a promising strategy to counter ischemic damage in tissue transplantation, signifying a broader therapeutic prospect. (197 words).

The growth factor content as an indicator of platelet counts in platelet-rich plasma.

BACKGROUND: Platelet contains growth factors that enhance tissue repair mechanisms, including epidermal growth factor (EGF), platelet-derived growth factor (PDGF-AA and -AB), and transforming growth factor (TGF)-ß. Autologous platelet-rich plasma (PRP) has been shown to significantly improve the treatment of tendon injuries compared with hyaluronic acid and placebo. The topic of agreement between platelet concentrations and growth factors has been covered in some previous studies, but growth factor levels did not correlate well with platelet concentrations. METHOD: In this study, autologous PRP was prepared by concentrating platelets through a J6-MI centrifuge. The automatic hematology analyzer Sysmex XN-20 was used to analyze the platelet concentration in PRP, and the PRP growth factors were determined by ELISA, including PDGF, transforming growth factor- ß1 (TGF-ß1), and EGF. Statistical analysis was conducted on data from 107 patients who received autologous PRP using Pearson correlation analysis. RESULTS: Pearson correlation analysis revealed PDGF, TGF, and EGF had a strong positive correlation with the platelet concentration of the final PRP product (r = 0.697, p < 0.0001; r = 0.488, p < 0.0001; r = 0.572, p < 0.0001, respectively) CONCLUSIONS: There was a strong positive correlation between the concentration of platelets in the final PRP product and the levels of PDGF-AB, TGF-ß, and EGF. These results suggested straightforward and cost-effective growth factor tests can provide valuable information about platelet content in PRP.

G protein-coupled receptor kinase 5 regulates thrombin signaling in platelets.

Background: Our prior genome-wide association study of thrombin-induced platelet aggregation identified a G protein-coupled receptor kinase 5 (GRK5) noncoding variant (rs10886430-G) that is strongly associated with increased platelet reactivity to thrombin. This variant predisposes to increased risk of stroke, pulmonary embolism, and venous thromboembolism. Objectives: To determine role of platelet specific GRK5 in platelet responses to agonists and injury. Methods: Platelets from GRK5 mutant mice have been shown to have increased thrombin sensitivity, indicating that GRK5 may be a negative regulator of platelet activation. However, this has not been studied in a platelet-specific manner. We therefore used platelet-specific GRK5 mutant mice and models of thrombosis and pulmonary embolism. Results: We now demonstrate that mice lacking GRK5 specifically in platelets had a mild increase in thrombin responses in vitro and a shortened time to arterial thrombosis in vivo. In addition, platelet GRK5 mutant mice had increased thrombin but not collagen-induced thrombus burden in a mouse model of pulmonary embolism. Conclusion: These data indicate that platelet GRK5 has a significant role in limiting platelet responses to thrombin.

PAR-2 gene expression data and morphology data of rabbit Achilles tenocytes stimulated with PDGF-BB in vitro.

The first set of data refers to PAR-2 gene expression with the target gene rbF2rl1 assessed in tenocytes harvested from New Zealand White Rabbits' Achilles tendons. These tenocytes were stimulated in vitro with 20 ng/mL platelet-derived growth factor-BB (PDGF-BB) and compared to the corresponding cell culture without growth factor PDGF-BB. In addition, three inhibitors were tested. In the presence or absence of 40 µM inhibitor concentration and 5 % fetal bovine serum, the following inhibitors were applied: SB203580 = inhibitor for MAPK; LY-294002 = inhibitor for PI3K; PD153035 = inhibitor for EGFR. As control, gene expression was assessed under DMSO = dimethyl sulfoxide (solvent of the inhibitors) or in medium = basal culture medium (with 10 % fetal bovine serum). The second set of data represents morphological aspects of cytoskeletal reorganization for rabbit Achilles tenocytes stimulated in vitro with 20 ng/mL PDGF-BB compared to the corresponding cell culture without PDGF-BB. Data on cell size, on F-actin immunohistochemical labeling intensity, α-tubulin immunohistochemical labeling intensity and on cell aspect ratio (length of the cell divided by its width) are presented. Moreover, analogous to the first set of data, cytoskeletal rearrangement in the presence or absence of the inhibitors SB203580, LY-294002 and PD153035 in the presence or absence of PDGF-BB were assessed.

A Comparison of Functional Outcomes in Rotator Cuff Repairs Using Adjunctive Bone Marrow Aspirate Concentrate vs. Bone Marrow Aspirate Concentrate With Platelet-Rich Plasma: A Systematic Review and Meta-Analysis.

Regenerative medicine, specifically bone marrow aspirate concentrate (BMAC) and platelet-rich plasma (PRP), has become a novel adjunct that orthopedic surgeons have started to use with surgical rotator cuff repairs (RCR). Thus, we are conducting this systematic review to determine if either RCRs with BMAC alone or with BMAC and PRP result in superior functional outcomes. We conducted a comprehensive search using five databases including PubMed, Web of Science, Embase, Scopus, and Cochrane. After duplicates were removed, 1205 studies were screened by title and abstract using Rayyan, resulting in three included studies (one BMAC with PRP and two BMAC only). Only studies that reported functional outcomes using the American Shoulder and Elbow Surgeons Shoulder Score and the University of California Los Angeles Shoulder Score were included. Changes in assessment scores from baseline to follow-up evaluation were quantified using the effect size and used in the meta-analysis for each group. Interpretation of treatment efficacy was represented using Cohen's d. The effect size of BMAC with PRP (Cohen's d = 2.19) was not significantly different (p = 0.76) from that of BMAC alone (Cohen's d = 2.35). Between-group differences in functional outcomes were Cohen's d = 0.16, which was not significant. Given the lack of superiority and the small sample size, more research is required before a conclusion can be drawn as to the benefits of combining PRP with BMAC for RCR. If functional outcomes are the same, using BMAC alone as an adjunct may be optimal to reduce resources used and cost. Future studies should be conducted with a larger pool as our primary limitation is that only three studies were included.

Frequency of human platelet antigens (HPA) in the Greek population as deduced from the first registry of HPA-typed blood donors.

BACKGROUND AND OBJECTIVES: Human platelet antigens (HPA) play a central role in foetal and neonatal alloimmune thrombocytopenia (FNAIT), post-transfusion purpura and some cases of platelet therapy refractoriness. The frequency distribution of HPA had not been studied in the Greek population before we started to create a registry of HPA-typed apheresis platelet donors. The aim of this study was the determination of the frequency of various HPA in the Greek population, through the establishment of a registry of typed donors. MATERIALS AND METHODS: Here, we report on the first 1000 platelet donors of Greek origin who gave informed consent and were genotyped for 12 pairs of antithetical HPA by Single Specific Primer-Polymerase Chain Reaction (SSP-PCR), including HPA-1, HPA-3, HPA-5 and HPA-15. Antigen frequencies are reported, and allele frequencies were calculated and compared with other European and non-European populations. Tested donors cover all ABO and Rhesus D antigen spectrum. RESULTS: Antigen and allele frequencies are very similar to other White populations. The frequency of HPA-1bb is 2.9% in our study, and the frequency of HPA-2b, HPA-4b, HPA-9b and HPA-15b is also slightly higher than in other literature reports, while the frequency of HPA-15b was found higher than that of HPA-15a. CONCLUSION: We report antigen and allele frequencies for a large array of clinically significant HPA for the first time in the Greek population. Frequencies are consistent with other European populations. This registry of HPA-typed platelet donors, available to donate on demand, is an important asset for the treatment of FNAIT cases in Greece.

Hypoxia-Responsive Biomimetic Nanobubbles for Oxygen Delivery Promote Synergistic Ischemic Stroke Protection.

Effective, precise, and controllable oxygen delivery is crucial for regulating the oxygenation balance of brain tissue at the early stages of acute ischemic stroke (AIS) because the absence of oxygen may result in a series of highly interconnected vascular-neural pathological events, including oxidative stress, inflammation, and neuroapoptosis. In this study, platelet membrane-reassembled oxygen nanobubbles (PONBs) were constructed for oxygen delivery to protect AIS. Benefiting from the preserved natural targeting ability of platelet membranes, oxygen can be controlled release into the hypoxia lesion at the preperfusion stage due to vascular injury targeting and oxygen sustained diffusion capability after PONBs administration. Furthermore, synergizing with bioactive components carried by platelet membranes, PONBs can inhibit post-AIS vascular occlusion and maintain blood-brain barrier integrity, thereby facilitating enhanced oxygen delivery of PONBs, establishing a positive feedback loop between oxygen delivery and AIS protection. Additionally, the accumulation of PONBs enhances the ultrasound imaging contrast, enabling precise localization and dynamic monitoring of AIS lesions. Thus, PONBs represent a promising strategy for the diagnosis and treatment of AIS.

Inflammation indices in association with periodontitis and cancer.

Inflammation is a complex physiological process that plays a pivotal role in many if not all pathological conditions, including infectious as well as inflammatory diseases, like periodontitis and autoimmune disorders. Inflammatory response to periodontal biofilms and tissue destruction in periodontitis is associated with the release of inflammatory mediators. Chronic inflammation can promote the development of cancer. Persistence of inflammatory mediators plays a crucial role in this process. Quantification and monitoring of the severity of inflammation in relation to cancer is essential. Periodontitis is mainly quantified based on the severity and extent of attachment loss and/or pocket probing depth, in addition with bleeding on probing. In recent years, studies started to investigate inflammation indices in association with periodontal diseases. To date, only few reviews have been published focusing on the relationship between blood cell count, inflammation indices, and periodontitis. This review presents a comprehensive overview of different systemic inflammation indices, their methods of measurement, and the clinical applications in relation to periodontitis and cancer. This review outlines the physiological basis of inflammation and the underlying cellular and molecular mechanisms of the parameters described. Key inflammation indices are commonly utilized in periodontology such as the neutrophil to lymphocyte ratio. Inflammation indices like the platelet to lymphocyte ratio, platelet distribution width, plateletcrit, red blood cell distribution width, lymphocyte to monocyte ratio, delta neutrophil index, and the systemic immune inflammation index are also used in hospital settings and will be discussed. The clinical roles and limitations, relationship to systemic diseases as well as their association to periodontitis and treatment response are described.

Autologous platelet concentrates after third molar extraction: A systematic review.

Surgical removal of impacted mandibular third molars is often followed by postoperative sequelae like pain, swelling, trismus, etc. This systematic review explored the benefits of applying different autologous platelet concentrates (APCs) in the extraction socket of third molars. For this systematic review, PubMed, EMBASE, Web of Science, and Scopus have been utilized, initially yielding 544 papers. The search was narrowed to randomized controlled trials (RCTs, n = 59) published before 2024, all comparing the outcome of applying APCs in the extraction socket of surgically removed impacted mandibular third molars with unassisted healing (blood clot). Most RCTs primarily assessed the impact of APCs on postoperative sequelae. Some RCTs looked at soft- and hard-tissue healing. Eleven studies used PRP, three PRGF, and 45 L-PRF. A detailed analysis revealed a large heterogeneity between studies rendering a meta-analysis impossible. Moreover, the risk of bias was considered high. In the majority of RCTs, the application of an APC resulted in statistically significant reductions of postoperative sequelae (lower pain intensity, lower consumption of analgesics, less postoperative edema, and a lower incidence of trismus and alveolar osteitis), as well as a faster soft tissue healing, and qualitatively and quantitatively better bone healing. A minority of studies reported significant differences in periodontal parameters distally from the second molar.

Analysis of Calculated Liver Scores for Long-Term Outcome in 423 Cutaneous Melanoma Patients.

Background: Neoadjuvant and adjuvant therapies are currently getting increasingly important in cutaneous melanoma (CM) management. However, there is still a lack of prognostic tools to identify which patients have a poor prognosis. There is increasing evidence that the liver score may be a potential prognostic parameter in different tumour types. The aim was to investigate whether established liver scores can establish the prognosis of CM. Methods: According to established methods, the APRI, the MELD score, the MELD-Na score and the De Ritis ratio were calculated from the laboratory values at the time of the initial diagnosis. Survival was compared with the Kaplan-Meier curve and tested with log-rank tests. Risk factors associated with cutaneous melanoma-specific survival (CMSS) and progression-free survival (PFS) were assessed by using the Cox proportional hazards regression model. To determine the diagnostic accuracy, we performed a time-dependent ROC analysis. Results: A total of 423 patients were included, including 141 patients in AJCC stage (2017) I (33.3%), 82 in stage II (19.4%), 128 in stage III (30.3%) and 72 in stage IV (17%). Median time until melanoma-specific death was 99 months (IQR: 37-126). In addition, 37.6% of patients relapsed with a median time to relapse of 88 months (IQR: 17.5-126). In all stages, tumour thickness and ulceration were independent markers for predicting CMSS and PFS (p < 0.05). The multivariable analysis with all stages showed no significant association with CM outcome for liver scores (p > 0.05). The subgroup analysis revealed that the APRI (≥0.2241) was associated with CMSS and PFS in melanoma stages I and II, independently of tumour thickness, age and ulceration (HR 2.57, 95% CI 1.14-5.75; HR 2.94, 95% CI 1.42-6.09, respectively). Conclusions: The 20-year prognosis of AJCC stage I and II CM was dependent on tumour thickness and the APRI. High tumour thickness and an APRI ≥ 0.2241 at the initial diagnosis were associated with a worse prognosis. Future studies should investigate the independent prognostic value of the APRI in low-stage CM. Furthermore, the APRI score could be a potential biomarker for nomograms.

Platelet and Lymphocyte-Related Parameters as Potential Markers of Osteoarthritis Severity: A Cross-Sectional Study.

BACKGROUND: Platelets and lymphocytes levels are important in assessing systemic disorders, reflecting inflammatory and immune responses. This study investigated the relationship between blood parameters (platelet count (PLT), mean platelet volume (MPV), lymphocyte count (LINF), and platelet-to-lymphocyte ratio (PLR)) and osteoarthritis (OA) severity, considering age, sex, and body mass index (BMI). METHODS: Patients aged ≥40 years were included in this cross-sectional study and divided into groups based on knee OA severity using the Kellgren-Lawrence (KL) grading system. A logistic regression model, adjusted for confounders, evaluated the ability of PLT, MPV, LINF, and PLR to categorize OA severity. Model performance in terms of accuracy, sensitivity, and specificity was assessed using ROC curves. RESULTS: The study involved 245 OA patients (51.4% female, 48.6% male) aged 40-90 years, 35.9% with early OA (KL < 3) and 64.1% moderate/severe OA (KL ≥ 3). Most patients (60.8%) were aged ≥60 years, and BMI was <25 kg/m2 in 33.9%. The model showed that a 25-unit increase in PLR elevates the odds of higher OA levels by 1.30 times (1-unit OR = 1.011, 95% CI [1.004, 1.017], p < 0.005), while being ≥40 years old elevates the odds by 4.42 times (OR 4.42, 95% CI [2.46, 7.95], p < 0.0005). The model's accuracy was 73.1%, with 84% sensitivity, 52% specificity, and an AUC of 0.74 (95% CI [0.675, 0.805]). CONCLUSIONS: Higher PLR increases the likelihood of moderate/severe OA, suggesting that monitoring these biomarkers could aid in early detection and management of OA severity. Further research is warranted to cross-validate these results in larger populations.

Insights into the Neutrophil-to-Lymphocyte Ratio and the Platelet-to-Lymphocyte Ratio as Predictors for the Length of Stay and Readmission in Chronic Heart Failure Patients.

Background/Objectives: Chronic heart failure (CHF) is characterized by complex pathophysiology, leading to increased hospitalizations and mortality. Inflammatory biomarkers such as the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) provide valuable diagnostic insights. METHODS: This study evaluates the prognostic relationship between NLR, PLR, and, in a specific subcohort, N-terminal pro B-type natriuretic peptide (NT-proBNP), alongside length of stay (LOS) and 90-day readmission rates in CHF patients, irrespective of heart failure phenotype. A retrospective analysis of 427 CHF admissions (males = 57.84%) was conducted. RESULTS: The mean age of the entire population was 68.48 ± 11.53 years. The average LOS was 8.33 ± 5.26 days, with a readmission rate of 73 visits (17.09%) for 56 patients. The NLR (3.79 ± 3.32) showed a low but positive correlation with the LOS (r = 0.222, p < 0.001). Conversely, the PLR (144.84 ± 83.08) did not demonstrate a significant association with the LOS. The NLR presented a low negative correlation for days until the next admission (r = -0.023, p = 0.048). In a prespecified subanalysis of 323 admissions, the NT-proBNP exhibited a low positive Pearson correlation with the NLR (r = 0.241, p < 0.001) and PLR (r = 0.151, p = 0.006). CONCLUSIONS: The impact of the NLR across heart failure phenotypes may suggest the role of systemic inflammation in understanding and managing CHF.

The Value of Systemic Inflammatory Indices for Predicting Early Postoperative Complications in Colorectal Cancer.

Background and Objectives: Systemic inflammatory indices have been largely investigated for their potential predictive value in multiple inflammatory, infectious, and oncological diseases; however, their value in colorectal cancer is still a subject of research. This study investigates the dynamics of pre- and postoperative values of NLR, PLR, SII, and MLR in patients with colorectal cancer and their predictive value for early postoperative outcomes. Materials and Methods: A 2-year retrospective cohort study was performed on 200 patients operated for colorectal adenocarcinoma. Systemic inflammatory indices were calculated based on complete blood count preoperatively and on the first and sixth postoperative days. The patients were divided into two groups based on their emergency or elective presentation. The pre- and postoperative values of serum inflammatory biomarkers and their correlations with postoperative outcomes were separately analyzed for the two study subgroups. Results: There were no significant differences in sex distribution, addressability, associated comorbidities, or types of surgery between the two groups. Patients in the emergency group presented higher preoperative and postoperative values of WBC, neutrophils, NLR, and SII compared to elective patients. The postsurgery hospital stays correlated well with pre- and postoperative day one and day six values of NLR (p = 0.001; 0.02; and <0.001), PLR (p < 0.001), SII (p = 0.037; <0.001; <0.001), and MLR (p = 0.002; p = 0.002; <0.001). In a multivariate analysis, reintervention risk was higher for emergency presentation and anemia, and lower in right colon cancer. In the emergency group, a multivariate model including age, MLR PO1, and pTNM stage was predictive for severe postoperative complications (AUC ROC 0.818). First-day postoperative inflammatory indices correlated well with sepsis, with the best predictive value being observed for the first postoperative day NLR (AUC 0.836; sensibility 88.8%; specificity 66.7%) and SII (AUC 0.796; sensitivity 66.6%; specificity 90%). For elective patients, the first postoperative day PLR and anemia were included in a multivariate model to predict Clavien-Dindo complications graded 3 or more (AUC ROC 0.818) and reintervention (AUC ROC 0.796). Conclusions: Easy-to-calculate and inexpensive systemic inflammatory biomarkers could be useful in predicting early postoperative outcomes in colorectal cancer for both elective and emergency surgery.

Platelet Rich Plasma Therapy in Achilles and Patellar Tendinopathies: Outcomes in Subjects with Diabetes (A Retrospective Case-Control Study).

Introduction: Diabetes mellitus (DM) is associated with a high risk of chronic degenerative Achilles (AT) and Patellar (PT) tendinopathies and ruptures. Growth factors (GFs) synthesis in diabetics is substantially decreased in human connective tissues, including in tendons. Platelet Rich Plasma (PRP), which is enriched in GFs, might prove of great help in tendon healing. The aim of the study was to assess whether pre-existent DM or Impaired Glucose Tolerance (IGT) could influence the clinical outcome in subjects undergoing PRP treatment. Methods: Sixty subjects with diabetes/pre-diabetes and sixty euglycemic controls, matched for sex and age, were enrolled. Patients suffering from proximal insertional PT and mid-portion AT, treated with PRP therapy, were included in the study. To assess the basal status and the efficacy of the therapy after 3 and 6 months, the Victorian Institute of Sport Assessment (VISA) questionnaire and the Ultrasound methodology study were used. Patient satisfaction was assessed by means of the Likert Scale. Results: In the population study at 6 months, the mean VISA-score increased (8.92 ± 0.67; p-value < 0.001). The improvement in the diabetic group was less evident compared to the controls (-2.76 ± 0.95; p-value = 0.003). Even though the improvement was poor, it was still significant. MCID analysis revealed that diabetics had higher risk of therapeutic unsuccess. Logistic regression analysis was applied to assess factors associated with unsatisfactory results (Likert-scale) of PRP treatment: AT (O.R.: 3.05; 95%CI: 1.40-6.64; p-value = 0.005), higher BMI values (O.R.: 1.02; 95%CI: 1.01-1.04; p-value = 0.01), and lower VISA score values at baseline (O.R.: 0.95; 95%CI: 0.90-0.99; p-value = 0.04). Conclusions: PRP treatment in AT and PT chronic tendinopathies resulted in less favorable results in subjects with diabetes compared with euglycemic subjects. Moreover, the subjects with PT showed better results than those with AT.

The Analysis of Neutrophil to Lymphocyte Ratio (NLR), Lymphocyte to Monocyte Ratio (LMR), and Platelet to Lymphocyte Ratio (PLR) in Patients with Adenoidectomy and Tonsillectomy.

Background/Objectives: Adenoidectomy and tonsillectomy are among the most commonly performed procedures in ENT practice. The neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR) are recognized inflammatory markers. This study aims to evaluate the changes in NLR, PLR, and LMR in patients undergoing adenoidectomy and tonsillectomy. Methods: The study group consisted of 980 patients who underwent adenoidectomy and/or tonsillectomy. Preoperative and postoperative inflammatory markers were measured in all patients. The NLR, LMR, and PLR values were then calculated and analyzed. Results: In patients undergoing adenoidectomy and/or tonsillectomy, the postoperative NLR was significantly lower than the preoperative NLR. Similarly, the postoperative LMR was significantly higher, and the postoperative PLR was significantly lower compared to their preoperative values. Conclusions: The significant changes in NLR, LMR, and PLR following adenoidectomy and/or tonsillectomy suggest a reduction in systemic inflammation post-surgery. These findings indicate that these procedures may contribute to the improvement of inflammatory status in patients, highlighting the potential role of these markers in monitoring surgical outcomes.

Subsequent Vaccination against SARS-CoV-2 after Vaccine-Induced Immune Thrombotic Thrombocytopenia.

Background: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but severe complication following vaccination with adenovirus vector-based COVID-19 vaccines. Antibodies directed against platelet factor 4 (PF4) are thought to be responsible for platelet activation and subsequent thromboembolic events in these patients. Since a single vaccination does not lead to sufficient immunization, subsequent vaccinations against COVID-19 have been recommended. However, concerns exist regarding the possible development of a new thromboembolic episode after subsequent vaccinations in VITT patients. Methods: We prospectively analyzed follow-up data from four VITT patients (three women and one man; median age, 44 years [range, 22 to 62 years]) who subsequently received additional COVID-19 vaccines. Platelet counts, anti-PF4/heparin antibody level measurements, and a functional platelet activation assay were performed at each follow-up visit. Additionally, we conducted a literature review and summarized similar reports on the outcome of subsequent vaccinations in patients with VITT. Results: The patients had developed thrombocytopenia and thrombosis 4 to 17 days after the first vaccination with ChAdOx1 nCoV-19. The optical densities (ODs) of anti-PF4/heparin antibodies decreased with time, and three out of four patients tested negative within 4 months. One patient remained positive even after 10 months post first vaccination. All four patients received an mRNA-based vaccine as a second vaccination against SARS-CoV-2. No significant drop in platelet count or new thromboembolic complications were observed during follow-up. We identified seven publications reporting subsequent COVID-19 vaccination in VITT patients. None of the patients developed thrombocytopenia or thrombosis after the subsequent vaccination. Conclusion: Subsequent vaccination with an mRNA vaccine appears to be safe in VITT patients.

Gingival Augmentation Using Injectable Platelet-Rich Fibrin (i-PRF)-A Systematic Review of Randomized Controlled Trials.

Background: In recent years, the utilization of blood concentrates in dentistry has become increasingly prevalent. In 2014, the development of injectable platelet-rich fibrin (i-PRF) was achieved. One of the key benefits of i-PRF is its ability to consistently release a range of growth factors. This review aimed to determine whether i-PRF could be used for gingival augmentation. Methods: The research involved a search of the PubMed, Embase, Scopus, and Google Scholar databases using the following search terms: ("microneedling" or "micro needling" or "injectable platelet-rich fibrin" or "i-PRF") and ("gingival augmentation" or "augmentation" or "attached gingiva" or "attached mucosa" or "soft tissue augmentation" or "KM" or "keratinized mucosa"). Results: Of the 668 results, 8 articles meeting the inclusion criteria were included in the article. The results of the studies analyzed indicated a significant increase in gingival thickness. Furthermore, some articles demonstrated an increase in keratinized tissue width. The augmentation of the gingival thickness with i-PRF yielded no inferior results in comparison to the free gingival graft, which is the current gold standard, resulting in a superior aesthetic outcome and a reduction in postoperative discomfort. Conclusions: This systematic review allowed the authors to conclude that the use of i-PRF or hyaluronic acid may be the first step towards developing a non-surgical method of gingival augmentation.

Flap-Free Tendon Coverage Using Autologous Fat Grafts Enhanced with Platelet-Rich Plasma and Growth Factors at a Secondary Level Hospital: A Case Report.

BACKGROUND: Autologous fat grafting, enriched with platelet-rich plasma (PRP), has been established as an effective and affordable treatment for various types of wound healing. However, its efficacy in managing wounds with tendon exposure has not been thoroughly investigated. METHODS: We report the case of a 40-year-old male who sustained a severe friction burn on his hand and forearm from a car accident, resulting in significant tissue loss and exposed extensor tendons. RESULTS: Traditional wound treatment strategies were not implemented due to specific patient circumstances. After initial surgical management failed to prevent necrosis and maintain coverage of the exposed tendons, the patient underwent a novel treatment involving autologous fat grafting combined with PRP and growth factors. The procedure was repeated twice within a month to promote granular tissue formation over that area and facilitate subsequent coverage with an epidermoreticular graft. By day 21 post-initial graft, the exposed tendons were 98% covered with granular tissue. Complete wound coverage was achieved by day 60, and by day 130 the patient had regained 90% functionality of the affected limbs. CONCLUSIONS: This case illustrates the potential of autologous fat grafting combined with PRP and growth factors as a viable, flap-free alternative for covering tendon exposures. This approach not only enhances wound healing but also supports functional recovery, underscoring the need for further research into its broader applicative potentials.

Intraovarian PRP injection improves oocyte quality and early embryo development in mouse models of chemotherapy-induced diminished ovarian reserve.

Intraovarian injection of platelet-rich plasma (PRP) has been recently proposed, with encouraging results to provide an alternative option to patients diagnosed with POR or POI. However, the broad spectrum of PRP effects on the reproductive function and the mechanisms of action in follicular activation, response to stimulation, and embryo quality have not yet been studied. In this study, we first induced poor ovarian reserve (POR) and premature ovarian insufficiency (POI) ovarian phenotypes in CD1 mice undergoing PRP or sham intraovarian injection. PRP administration reduced those alterations induced by chemotherapy in ovarian stroma and follicle morphology in both the POR and POI conditions. After ovarian stimulation, we found that PRP did not modify the MII-oocyte yield. Nevertheless, the amount of obtained 2-cell embryos and fertilization rate were increased, being especially relevant for the POI model. Further in vitro embryo culture led to improved blastocyst formation rates and higher numbers of good quality blastocysts in PRP vs. sham females in both the POR and POI conditions. These positive results of PRP injection were also validated in the C57Bl/6 stain. Altogether, our findings suggest a possible effect on oocyte and embryo quality. This effect is likely due to the increase of local paracrine signaling through the released growth factors in PRP-treated ovaries.

Long-term stability of frozen platelet-rich plasma under -80 °C storage condition.

Platelet rich plasma (PRP) is increasingly used in various fields of medicine, aiming to regeneration and repair damaged tissues, cells and organs. High concentration of bioactive molecules including growth factors, cytokines and chemokines are the rationale of using PRP. The aim of this study is to analyze the effect of frozen on the levels of growth factors. In our study, PRP samples were isolated from 50 healthy volunteers using the Trima Accel blood cell separator. The concentration of growth factors such as platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF-1) and platelet factor 4 (PF-4) were assessed in fresh PRP and frozen PRP stored at -80 °C for one to twelve months. The study found that count of platelet in all fresh and frozen PRP samples was significantly increased compared to whole blood baseline. There was no significant difference in the concentrations of PDGF-BB, bFGF, VEGF, and PF-4 between fresh and frozen samples. The concentrations of EGF and IGF in Frozen-PRP group were significantly higher than those in Fresh-PRP group. And the storage condition of -80 °C is suitable for PRP, which will not lead to a decrease in growth factors concentration for at least 6 months.