Long-acting PGE2 and Lisinopril Mitigate H-ARS

Area of Science:

• Hematology
• Radiation Oncology
• Pharmacology

Background:

• Thrombocytopenia is a life-threatening complication of hematopoietic-acute radiation syndrome (H-ARS), increasing hemorrhage risk.
• Current therapies for H-ARS lack sufficient efficacy in mitigating bleeding and improving survival.
• Megakaryocyte (MK) and endothelial cell interactions are vital for effective thrombopoiesis.

Purpose of the Study:

• To evaluate the efficacy of a combination therapy using 16,16-dimethyl prostaglandin E2 (dmPGE2) and lisinopril in treating thrombocytopenia in murine models of H-ARS.
• To investigate the impact of this combination therapy on survival rates, MK recovery, and endothelial cell function following total-body irradiation (TBI).

Main Methods:

• Murine models of H-ARS were established using varying doses of TBI (7.75 Gy and 4 Gy).
• Mice were treated with dmPGE2, lisinopril, a combination of both, or vehicle control.
• Survival rates, bone marrow MK numbers, circulating platelet counts, MK maturation, platelet function, and sinusoidal endothelial cell populations were assessed.

Main Results:

• Both dmPGE2 and lisinopril monotherapies increased survival following 7.75 Gy TBI compared to controls.
• The combination therapy of dmPGE2 and lisinopril significantly enhanced survival beyond that achieved by either agent alone.
• Sublethal TBI (4 Gy) resulted in reduced MKs and platelets, impaired MK maturation, and dysfunctional platelets.
• dmPGE2, alone and in combination with lisinopril, improved the recovery of bone marrow MKs and peripheral platelets.
• The combination therapy accelerated the recovery of specific endothelial cell populations (Lin-CD45-CD31+Sca-1-) that were reduced by TBI.

Conclusions:

• Combined dmPGE2 and lisinopril therapy demonstrates superior efficacy in improving survival and mitigating thrombocytopenia in H-ARS models.
• The therapeutic benefits are attributed to the promotion of MK lineage recovery and the restoration of the MK niche, including endothelial cells.
• This combination therapy represents a promising strategy for managing H-ARS complications.