Thrombin in the Activation of the Fluid Contact Phase in Patients with Hereditary Angioedema Carrying the F12 P.Thr309Lys Variant.

Hereditary angioedema due to pathogenic FXII variants (HAE-FXII) is a rare dominant disease caused by increased activation of the plasma contact system. The most prevalent HAE-FXII variant, c.1032C > A p.Thr309Lys (FXII309Lys), results in a smaller FXII protein with increased sensitivity to fluid-phase activation by poorly understood mechanisms. We aimed to investigate the functionality of the FXII309Lys variant in 33 HAE-FXII patients, 25 healthy controls and 46 patients with congenital disorders of glycosylation (CDG). Activation of the plasma contact system was assessed by western blot and amidolytic assay in basal conditions or after treatment with either artificial or physiological activators. Recombinant wild-type and FXII309Lys variants were expressed in S2 insect (Drosophila) cells. Amidolytic and fibrin generation assays were performed in fresh plasma samples. FXII309Lys samples exhibited an increased electrophoretic mobility comparable with N-glycan-deficient FXII from CDG patients and asialo-FXII generated by neuraminidase treatment. They presented increased sensitivity to activation by dextran sulphate and silica which resulted in the generation of an aberrant 37-kDa heavy chain. We did not observe increased susceptibility of FXII309Lys to proteolysis by exogenous or tPA-generated plasmin. However, both exogenous and endogenous thrombin cleaved the FXII309Lys variant, releasing a 37-kDa fragment and resulting in enhanced proteolytic activation on the fluid phase. This model supports a sequential proteolytic activation process involving thrombin priming of FXII309Lys, followed by kallikrein cleavage and generation of active ßFXIIa. The present results and the observation that angioedema episodes in HAE-FXII patients occur predominantly during hypercoagulable situations suggest a key role for thrombin.

Sistemas genéticos para un nuevo abordaje del riesgo de progresión de la retinopatía diabética / Genetic systems for a new approach to risk of progression of diabetic retinopathy

OBJETIVO: Evaluar el riesgo de progresión de la retinopatía diabética (RD) utilizando nuevas estrategias para obtener información genética en diabéticos tipo 2 (DT2) basadas en interferencia por ácido ribonucleico (ARN). MATERIAL Y MÉTODOS: Estudio multicéntrico, prospectivo de casos-controles en 132 participantes divididos en: grupo DT2 (GDT2) con RD (+RD) y sin RD (-RD) (n = 77) y grupo control (GC) (n = 55). Tras entrevista personal y examen oftalmológico, se extrajeron lágrimas para análisis molecular (expresión de micro-ARN [miARN] [miRCURY™ ARN Isolation Kit, Qiagen]). En 18 muestras (GDT2+RD = 6; GDT2-RD = 6; GC = 6) obtuvimos librerías de 137 vs. 140 pares de bases (GeneMapper, Applied Biosystems) y realizamos secuenciación de próxima generación (NGS). El programa SPSS 15.0 vehiculizó el análisis estadístico. RESULTADOS: Edad media: 67 ± 12 años en GDT2 vs. 55 ± 21 años en GC. Distribución hombres/mujeres: 51/28 en GDT2 vs. 25/30 en GC. Los antecedentes familiares de DM, cumplir dieta, fumar, beber y realizar ejercicio mostraron diferencias significativas entre grupos (p < 0,001). Con 20-25 μL de lágrimas extrajimos 9,42 ± 3,30 ng/mL de ARN purificado, con diferencias significativas entre GDT2/GC (p = 0,002) y GDT2+RD/GC (p = 0,004). La expresión lagrimal de miARN en GDT2 correlacionó directamente con: edad/obesidad/duración de DM (p < 0,05), e indirectamente con: agudeza visual (p < 0,05). Hemos identificado 14 miARN relacionados con la presencia, mecanismos patogénicos y factores de riesgo para la progresión de la RD. CONCLUSIONES: Proponemos utilizar lágrimas como fuente de información genética para la DM. Los miARN específicos implicados en desarrollo o progresión de la RD pueden utilizarse como biomarcadores moleculares y, a partir de ellos, desarrollar futuras bioterapias

OBJECTIVE: To evaluate the risk of progression of diabetic retinopathy (DR) using new strategies to obtain genetic information in type 2 diabetes (T2D) based on interfering ribonucleic acid (RNA). MATERIAL AND METHODS: A prospective multicentre case-control study of 132 participants was distributed into: T2D with (+DR) or without (-DR) (T2DG; n = 77), and a control group (CG; n = 55). After an eye examination and personal interview, tears were collected for molecular analysis (expression of microRNAs [miRNAs] (miRCURY(TM) ARN Isolation Kit, Qiagen)]. Libraries, 137 vs. 140 bp (GeneMapper, Applied Biosystems), were obtained in 18 samples (T2DG+DR = 6; T2DG-DR = 6; CG = 6) by performing next-generation sequencing (NGS). SPSS 15.0 statistical program was used to perform data analysis. RESULTS: The mean age was 67 ± 12 years in the T2DG vs. 55 ± 21 years in the CG. Distribution men/women: 25/30 in T2DG vs. 51/28 in CG. A family history of DM, diet compliance, smoking, drinking and exercise, showed significant differences between groups (P<.001). A 20-25 microlitre sample of tears contained a mean of 9.42 ± 3.30 ng/mL of purified ARN, with significant differences between T2DG/CG (P=.002) and T2DG+RD/CG (P=.004). Tear expression of miARNs in T2DG directly correlated with age/obesity/T2D duration (P<.05), and indirectly with visual acuity (P<.05). A total of 14 miRNAs related to the presence, pathogenic mechanisms and risk factors for the progression of diabetic retinopathy, were identified. CONCLUSIONS: We propose to use tears as a source of genetic information for DM. Specific miRNAs involved in DR development and/or progression can be used as molecular biomarkers, and based on these, for developing future biotherapies