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Defective signal transduction in platelets from cirrhotics is associated with increased cyclic nucleotides

G Laffi1, F Marra, P Failli

  • 1Istituto di Clinica Medica II, University of Florence, Italy.

Gastroenterology
|July 1, 1993
PubMed

Insights

Platelet signal transduction is impaired in cirrhosis due to reduced calcium signaling and increased cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels. These findings reveal new mechanisms behind defective platelet function in advanced cirrhosis.

Area of Science:

  • Biochemistry
  • Hematology
  • Cell Biology

Background:

  • Patients with advanced cirrhosis exhibit impaired platelet aggregation, linked to intrinsic platelet abnormalities.
  • Understanding the molecular basis of these platelet defects is crucial for managing bleeding risks.

Purpose of the Study:

  • To investigate the activating and inhibitory signal transduction pathways in platelets of cirrhotic patients.
  • To identify specific molecular mechanisms underlying defective platelet function in cirrhosis.

Main Methods:

  • Washed platelets were analyzed from 12 cirrhotic patients and 12 healthy controls.
  • Measurements included thrombin-stimulated inositol trisphosphate production, cytosolic calcium changes, Na+/H+ antiporter activity, and basal cyclic nucleotide levels (cAMP and cGMP).

Main Results:

  • Cirrhotic platelets showed a fivefold reduction in thrombin-stimulated inositol 1,4,5-trisphosphate production and diminished cytosolic calcium responses.
  • Activity of the platelet Na+/H+ antiporter was significantly lower in cirrhotic patients.
  • Basal intraplatelet levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were significantly elevated in cirrhotic patients.

Conclusions:

  • Defective early platelet signal transduction in cirrhosis is associated with increased platelet cAMP and cGMP.
  • These findings elucidate novel mechanisms contributing to impaired platelet function in advanced cirrhosis.
  • This research provides insights into the cellular dysfunctions affecting hemostasis in liver disease.
Abstract

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