Comparative study between two bleeding grading systems of immune thrombocytopenia purpura

Human Disabled-2 regulates thromboxane A2 signaling for efficient hemostasis in thrombocytopenia

Understanding platelet protein functions facilitates better assessment of platelet disorders. Megakaryocyte lineage-restricted human Disabled-2 knock-in (hDAB2-KI) mice are generated to delineate the functions of hDab2, a regulator of platelet function, in the control of bleeding associated with thrombocytopenia. Here we show that hDab2-KI mice with thrombocytopenia display decreased bleeding time when compared to the control mice. hDab2 augments thromboxane A2 (TxA2) mimetic U46619- but not other agonists-stimulated granule secretion, integrin activation, and aggregation at a lower platelet concentration in vitro. Binding of hDab2 to phosphatidic acid (PA) facilitates formation of the PA-hDab2-AKT complex leading to an increase in U46619-stimulated AKT-Ser473 phosphorylation and the first wave of ADP/ATP release. Consistent with these findings, hDab2 expression in platelets from patients with immune thrombocytopenic purpura is positively correlated with U46619-stimulated ATP release, which in turn inversely correlated with their bleeding tendency. hDab2 appears crucial in regulating bleeding severity associated with thrombocytopenia by a functional interplay with ADP/ATP release underlying TxA2 signaling.

Assessing uptake of the core outcome set in clinical trials for immune thrombocytopenia: A cross-sectional analysis

INTRODUCTION

Clinical trials (CTs) guide clinical practice, but inconsistent outcome reporting presents challenges. To increase comparability, a core outcome set (COS) was created for primary Immune thrombocytopenia (ITP) in 2009 to standardize outcome measurements. We aimed to evaluate uptake of the primary ITP COS in CT registries.

MATERIALS & METHODS

Our cross-sectional analysis employed a search string on ClinicalTrials.gov and ICTRP for phase III/IV CTs in June 2023. Inclusion criteria consisted of subjects with primary ITP, study was registered five years before COS publication to June 26, 2023, and assessed effectiveness of interventions. Two investigators extracted data in a masked, duplicate manner. Interrupted time series analysis, ANOVAs, and correlation analyses were conducted to assess the main outcome of COS uptake pre/post COS publication.

RESULTS

The search identified 131 eligible trials for data extraction. Altogether, 38.2 % (50/131) followed IWG platelet response guidelines. An alternative platelet count measurement was 50,000 × 109 L, with 46.56 % (61/131) of trials reporting it. The most measured outcome was adverse events (106/131, 80.9 %). Remaining secondary outcomes were measured in <50 % of studies. After COS publication, there was a statistically non-significant 0.03 % (p = 0.50, CI 95 % = [-0.06, 0.13]) 0.03 % (p = 0.50, CI 95 % = [-0.06, 0.13]) increase in the monthly trend of COS-defined outcomes.

CONCLUSION

We found a non-significant increase in uptake of the ITP COS since its publication and highlighted the lack of standardization among endpoints within ITP clinical trials. Our analysis highlights the need for heightened awareness and a COS update that acknowledges the variability in clinical trials.