RESUMO
Platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are selective blood fractions obtained by cen¬trifugation. They act locally on inflammation and immunity as adjuvant homeostatic modulators during tissue regeneration. In recent years, many methods for achieving these blood concentrates have emerged, whose parameters of time and force of centrifugation presented themselves as critical, conflicting, and poorly understood points. Thus, the present study aimed to evaluate the effect of different centrifugal experimental parameters on the concentration of cells and platelets in samples of anticoagulated blood. Blood samples were centrifuged by forces of 200, 400 and 800 x g for 5, 10 and 15 minutes of centrifugation times to obtain three fractions: a) platelet-poor plasma (PPP), b) leukocyte-rich plasma (L- PRP) and c) red blood cell sed¬iment (RBC). The leukocyte and platelet content of each centrifuged fraction was measured by automated flow cytometry associated with the peroxidase reaction for differential leukocyte count. The application of 200 x g generated a more significant dispersive content of leukocytes and platelets in the supernatant fraction of PPP when compared to the other two strength ranges. However, it presented the highest concentration of platelets in the sediment (P <0.05 ANOVA), representing a loss of total mass during processing. The 400 and 800 x g forces showed leukocytes and platelets condensed in the L-PRP fraction and lower levels in the sedi¬ment, demonstrating the greater effectiveness of buoyancy in the resuspension of these sedimented elements. Our experimental data showed that the concentration and organization of leukocytes and platelets in the centrifuged blood matrices are very sensitive to variations in g force and centrifugation time, thus generating products with different biological composition and characteristics, and with specific potential therapeutic effects. The present study did not focus on comparing authoring methods, but on presenting the impact of methodological variations on the biological nature of centrifuged blood matrices. Further in vivo studies are needed to assess the specific clinical effect of each methodological change.
Assuntos
Plaquetas , Citometria de Fluxo , Leucócitos , Fibrina Rica em Plaquetas , Plasma Rico em PlaquetasRESUMO
OBJECTIVE: Non-healing venous leg ulcers (VLUs) have a significant effect on patients' quality of life and substantially increase expenditures in health-care systems. The aim of this study was to evaluate the clinical efficacy of the Calendula officinalis extract, Plenusdermax, in the treatment of VLUs. METHOD: Patients treated with Calendula officinalis extract (n=38) and control patients (n=19) were evaluated every two weeks for 30 weeks or until their ulcers healed. Assessments included determination of the wound area by planimetry, infection control, and evaluation of the clinical aspects of the wounds. The percentage of healing velocity per week (%HVw), taking the initial area at baseline into account, was also determined. RESULTS: The proportion of the treatment patients achieving complete epithelialisation was 72 % and 32 % in the treatment and control groups, respectively. The average healing time was approximately 12 weeks in the treatment group and 25 % in control patients. Patients with ulcers treated with Calendula officinalis extract had a significant 4-fold increase in percentage healing velocity per week, 7.4 %, compared with 1.7 % in the control group. No adverse events were observed during the Calendula officinalis extract treatment. CONCLUSION: Our findings indicate that Calendula officinalis extract is an effective treatment for VLUs. DECLARATION OF INTEREST: The authors have no conflict of interest.