title: Studies of circulating microparticle release in peripheral blood after pancreatic islet transplantation.
abstract: The loss of graft function after intraportal islet transplantation is likely multifactorial involving allogeneic rejection, recurrent autoimmunity, graft exhaustion due to a marginally implanted islet mass, immunosuppressant toxicity, and impaired β-cell regeneration. Because early markers of the loss of β-cell mass or function are lacking, monitoring of islet function remains a challenging issue. We have reported herein monitoring of membrane procoagulant microparticles (MPs) as markers of cell stress in the plasma of three recipients with various clinical histories. Early kinetics of C-peptide and MPs followed identical patterns during the first weeks after transplantation; a major increase probably reflected processes related to cell infusion and islet engraftment. Importantly in the case of rejection, MPs and C-peptide showed opposite patterns. A fall in C-peptide was associated with enhanced insulin needs. Our results suggested that a peak in MP levels might indicate rejection with prognotic value. Treatment of the loss of islet function by a new islet infusion or steroid therapy returned MP and C-peptide levels to their baselines with concomitant restoration of islet function. In the patient with suspected acute cellular rejection, MPs also appeared to be sensors of immunosuppressive steroid therapy.
authors.affiliation: Laboratory of Vascular Biology, Immunology and Hematology Institute, INSERM UMR 770, Faculty of Medicine, University of Strasbourg, Le Kremlin-Bicêtre, France.
authors.forename: F
authors.initials: F
authors.lastname: Toti
authors.forename: F
authors.initials: F
authors.lastname: Bayle
authors.forename: T
authors.initials: T
authors.lastname: Berney
authors.forename: H
authors.initials: H
authors.lastname: Egelhofer
authors.forename: M J
authors.initials: MJ
authors.lastname: Richard
authors.forename: M
authors.initials: M
authors.lastname: Greget
authors.forename: D
authors.initials: D
authors.lastname: Masson
authors.forename: F
authors.initials: F
authors.lastname: Zobairi
authors.forename: P Y
authors.initials: PY
authors.lastname: Benhamou
authors.forename: L
authors.initials: L
authors.lastname: Kessler
mesh_terms: D000328:Adult; D002096:C-Peptide / Q000737:chemistry; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D002986:Clinical Trials as Topic; D003029:Coagulants / Q000378:metabolism; D005260:Female; D006680:HLA Antigens / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013256:Steroids / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D002096:C-Peptide; D003029:Coagulants; D006680:HLA Antigens; D007166:Immunosuppressive Agents; D007328:Insulin; D013256:Steroids