Changes on the Structural Architecture and Growth Factor Release, and Degradation in Equine Platelet-Rich Fibrin Clots Cultured Over Time.

The aims of the present study were (1) to describe the microscopic and ultrastructural appearance of equine platelet-rich fibrin (PRF) clots and (2) to determine the release and degradation of transforming growth factor beta 1 (TGF-ß1) and insulin-like growth factor type I (IGF-I) from PRF clots incubated over 14 days. Whole blood from six horses was collected into plain tubes and centrifuged at 240 g for 8 minutes. Clots were evaluated by histology and by both transmission and scanning electronic microscopy (TEM and SEM). Growth factor concentrations were measured by ELISA at 48-hour intervals over 14 days and analyzed by one-way repeated-measures ANOVA. Histology showed a clot composed by a fibrin layer and a cellular layer with platelets and leukocytes. Scanning electron microscopy showed the cells trapped by an incipient fibrin network at 1 hour. At day 8, these cells were embedded by an incipient fibrin network. At day 14, the leukocytes and platelet aggregates from the clot were imbibed in an organized web of fibrin fibrils. TEM exhibited platelets with preserved cytoplasm and alpha granules randomly scattered at day 8, and damaged platelets with interrupted cytoplasm and organelle emigration to the periphery at day 14. TGF-ß1 and IGF-I concentrations showed a progressive increase until day 14. TGF-ß1 was released from PRF clots in a gradual and controlled manner, and increasing its concentration for two weeks, which supports TEM findings indicating that platelets began disintegrating by day 14. Furthermore, IGF-I production and release from PRF clots is sustained over time.

Effects of the breed, sex and age on cellular content and growth factor release from equine pure-platelet rich plasma and pure-platelet rich gel.

BACKGROUND: There is no information on the effects of the breed, gender and age on the cellular content and growth factor (GF) release from equine pure-platelet rich plasma (P-PRP) and pure-platelet rich gel (P-PRG). The objectives of this study were: 1) to compare the cellular composition of P-PRP with whole blood and platelet poor plasma (PPP); 2) to compare the concentration of transforming GF beta 1 (TGF-ß1) and platelet derived GF isoform BB (PDGF-BB) between P-PRP treated with non-ionic detergent (P-PRP+NID), P-PRG (activated with calcium gluconate -CG-), PPP+NID, PPP gel (PPG), and plasma and; 3) to evaluate and to correlate the effect of the breed, gender and age on the cellular and GF concentration for each blood component. Forty adult horses, 20 Argentinean Creole Horses (ACH) and, 20 Colombian Creole Horses (CCH) were included. Data were analyzed by parametric (i.e.: t-test, one way ANOVA) and non parametric (Kruskal-Wallis test, Wilcoxon test) tests. Correlation analysis was also performed by using the Spearman and Pearson tests. A p ≤ 0.05 was set as significant for all tests. All the blood components were compared for platelet (PLT), leukocyte (WBC), TGF-ß1 and PDGF-BB concentrations. The effect of the breed, gender and age on these variables was analyzed. A P ≤ 0.05 was accepted as significant for all the tests. RESULTS: PLT counts were 1.8 and 0.6 times higher in P-PRP than in whole blood and PPP, respectively; WBC counts were 0.5 and 0.1 times lower in P-PRP, in comparison with whole blood and PPP, respectively. TGF-ß1 and PDGF-BB concentrations were 2.3 and 262 times higher, respectively, in P-PRG than in plasma, and 0.59 and 0.48 times higher, respectively, in P-PRG than in PPG. P-PRG derived from CCH females or young horses presented significantly (P < 0.001) higher PDGF-BB concentrations than P-PRG derived from ACH males or older horses. CONCLUSIONS: Our results indicated that P-PRP obtained by a manual method was affected by intrinsic factors such as the breed, gender and age. Equine practitioners should be aware that cellular and GF release from P-PRP/P-PRG could change according with the intrinsic variables associated with a patient in particular.

Determinación de marcadores inflamatorios y anabólicos articulares en caballos jóvenes estabulados con osteocondrosis tarsocrural / Determination of inflammatory and anabolic joint markers in stabled young horses with tarsocrural ostechondrosis

Objetivo. Describir los valores de las concentraciones en líquido sinovial (LS) de prostaglandina E2 (PGE2), óxido nítrico (NO), ácido hialurónico (HA) y proteína total (PT) en caballos jóvenes estabulados con osteocondrosis (OC) tarsocrural y correlacionar los valores de estos marcadores con el recuento total de células del LS, el grado de efusión sinovial (ES) y con el grado de cojera (GC). Materiales y métodos. Las concentraciones en LS de PGE2 fueron determinadas mediante ELISA, las de NO fueron valoradas por la reacción de Greiss, las de HA fueron medidas con radioinmunoanálisis RIA y las de PT mediante refractometría. Resultados. Once caballos entre 8 y 36 meses fueron incluidos. La mediana y el rango (R) de los grados de ES y GC fueron de 1.5 (R: 0.5-2) y 0 (R: 0-2), respectivamente. La mediana de la concentración de PGE2 y NO, respectivamente fue 130.6 pg/mL (R: 41-231.7 pg/mL) y 2.92 mM (R: 1.3-6.3 mM).. La concentración de HA presentó una mediana de 312.4 mg/mL (R: 70-543.5 mg/mL). La concentración promedio de PT fue de 1.2±-0.36 g/dL. Se observó correlación negativa estadísticamente significativa entre las concentraciones sinoviales de HA y el grado de efusión sinovial (ñ=-0.7; p= 0.048) y el grado de cojera (ñ=-0.78; p=0.014). Conclusiones. La concentración de HA en LS de caballos con OC podría estar negativamente correlacionada con la gravedad de los signos clínicos.