INVESTIGATION INTO P2Y RECEPTOR FUNCTION IN PLATELETS FROM PATIENTS WITH SEPSIS

Area of Science:

• Immunology
• Hematology
• Critical Care Medicine

Background:

• Sepsis involves hemostatic dysfunction and inflammation, with platelets playing a dual role in both processes.
• Platelet function, particularly P2Y receptor (P2YR) activation, is crucial for their hemostatic and inflammatory roles.
• Understanding alterations in platelet function during sepsis is vital for managing this life-threatening condition.

Purpose of the Study:

• To investigate whether P2YR-dependent hemostatic and inflammatory functions of platelets are altered in sepsis patients.
• To compare platelet function in sepsis patients with those experiencing mild sterile inflammation (cardiac surgery patients).
• To elucidate the specific impact of sepsis on platelet aggregation and chemotaxis.

Main Methods:

• Platelets were isolated from sepsis patients (community-acquired pneumonia), cardiac surgery patients, and healthy donors.
• In vitro platelet aggregation assays were performed using adenosine diphosphate (ADP) stimulation.
• Platelet chemotaxis assays were conducted using N-formylmethionyl-leucyl-phenylalanine (fMLP) as a chemoattractant.

Main Results:

• Both cardiac surgery and sepsis induced inflammation, with increased neutrophils and a trend towards decreased platelets.
• Platelet aggregation in response to ADP was preserved in all patient groups and controls.
• Platelets from sepsis patients demonstrated a significant loss of chemotaxis towards fMLP, persisting from admission to discharge.

Conclusions:

• Platelets from sepsis patients exhibit impaired P2Y1 receptor-dependent inflammatory function, specifically chemotaxis.
• This loss of platelet inflammatory function in sepsis is distinct from alterations observed in sterile inflammation.
• Further research is needed to determine if this is due to platelet recruitment or immune dysregulation in sepsis.