Prokineticin-1:a novel mediator of the inflammatory response in third-trimester human placenta

Prokineticin-1 (PK1) is a recently described protein with a wide range of functions, including tissue-specific angiogenesis, modulation of inflammatory responses, and regulation of hemopoiesis. The aim of this study was to investigate the localization and expression of PK1 and PK receptor-1 (PKR1), their signaling pathways, and the effect of PK1 on expression of the inflammatory mediators cyclooxygenase (COX)-2 and IL-8 in third-trimester placenta. PK1 and PKR1 were highly expressed in term placenta and immunolocalized to syncytiotrophoblasts, cytotrophoblasts, fetal endothelium, and macrophages. PK1 induced a time-dependent increase in expression of IL-8 and COX-2, which was significantly reduced by inhibitors of Gq, cSrc, epidermal growth factor receptor (EGFR), and MAPK kinase. Treatment of third-trimester placenta with 40 nm PK1 induced a rapid phosphorylation of cSrc, EGFR, and ERK1/2. Phosphorylation of ERK1/2 in response to PK1 was dependent on sequential phosphorylation of cSrc and EGFR. Using double-immunofluorescent immunohistochemistry, PKR1 colocalized with IL-8 and COX-2 in placenta. These data suggest that PK1 may have a novel role as a mediator of the inflammatory response in placenta

Severe bleeding diatheses in an elderly patient with combined type autoantibody against factor XIII A subunit; novel approach to the diagnosis and classification of anti-factor XIII antibodies

IntroductionAcquired factor XIII (FXIII) deficiency due to autoantibody is a rare, severe bleeding diathesis. Its laboratory diagnosis and classification represents a difficult task.AimIntroduction of novel approaches into the diagnosis and characterization of anti‐FXIII autoantibody and demonstration of their use in the diagnosis of a patient with autoimmune FXIII deficiency.MethodsFactor XIII activity, FXIII antigen levels and the titre of anti‐FXIII‐A antibody were monitored throughout the course of the disease. FXIII activity was measured by ammonia release assay; FXIII‐A2B2 complex, total and free FXIII‐B concentrations were determined by ELISAs. The binding constant for the interaction of the autoantibody with recombinant FXIII‐A2 (rFXIII‐A2) and FXIII‐A2B2 was determined by surface plasmon resonance (SPR). The inhibitory capacity of IgG was expressed as the concentration exerting 50% inhibition of FXIII activation/activity (IC50). The truncation of FXIII‐A by thrombin was monitored by western blotting. The inhibition of Ca2+ ‐induced FXIII activation and active FXIII (FXIIIa) were assessed by FXIII activity assay.ResultsThe antibody bound to rFXIII‐A2 and FXIII‐A2B2 with high affinity and accelerated the decay of supplemented FXIII concentrate. An IC50 value of 170.1 μg IgG·mL−1 indicated effective FXIII neutralization. The main neutralizing effect of the autoantibody was the inhibition of FXIIIa. After 2 months, due to combined therapeutic modalities, the autoantibody disappeared and FXIII activity significantly elevated.ConclusionThe anti‐FXIII‐A autoantibody exerted a combined effect including inhibition of FXIIIa and acceleration of FXIII decay in the plasma. IC50 and binding constant determinations added important information to the characterization of the autoantibody