title: New method for detection of heart allograft rejection: validation of sensitivity and reliability in a rat heterotopic allograft model.
abstract: BACKGROUND
  Patients with inflammatory heart muscle diseases would benefit from a safe, convenient, rapidly performed diagnostic technique with real-time results not involving tissue removal. We have performed a detailed evaluation of detection of heart allograft rejection by autofluorescence in a heterotopic abdominal rat heart allograft model ex vivo.
  
  
  RESULTS
  Recipient rats with allograft (Lewis to Fisher 344; n=71) and isograft (Lewis to Lewis; n=33) hearts, treated with cyclosporine or untreated, were killed at days 2, 4, 7, 14, 21, 28, and 56 after transplant. Nontransplant controls with (n=24) or without (n=24) immunosuppressive therapy were also studied. When the rats were killed, autofluorescence spectra were acquired under blue-light excitation from midtransverse ventricular sections of native and transplanted hearts. Corresponding sections were then evaluated pathologically by a modified International Society for Heart and Lung Transplantation (ISHLT) grading schema. The spectral differences between rejecting and nonrejecting hearts were quantified by linear discriminant functions, producing scores that decreased progressively with increasing severity of tissue rejection. Mean+/-SD discriminant function scores were 2.9+/-1.6, 1.8+/-2.2, -0.1+/-2.8, -1.2+/-2.3, and -2.3+/-3.0 for isografts and allograft ISHLT grades 0, I, II, and III, respectively (Spearman rank-order correlation -0.6; P<0.001, test for trend). Cyclosporine had no detectable effect on the spectra.
  
  
  CONCLUSIONS
  The correlation between changes in autofluorescence spectra and ISHLT rejection grade strongly supports the possibility of catheter-based, fluorescence-guided surveillance of rejection.
authors.affiliation: Biomax Technologies, Inc, Vancouver, BC.
authors.forename: D C
authors.initials: DC
authors.lastname: Morgan
authors.forename: J E
authors.initials: JE
authors.lastname: Wilson
authors.forename: C E
authors.initials: CE
authors.lastname: MacAulay
authors.forename: N B
authors.initials: NB
authors.lastname: MacKinnon
authors.forename: J A
authors.initials: JA
authors.lastname: Kenyon
authors.forename: P S
authors.initials: PS
authors.lastname: Gerla
authors.forename: C
authors.initials: C
authors.lastname: Dong
authors.forename: H
authors.initials: H
authors.lastname: Zeng
authors.forename: P D
authors.initials: PD
authors.lastname: Whitehead
authors.forename: C R
authors.initials: CR
authors.lastname: Thompson
authors.forename: B M
authors.initials: BM
authors.lastname: McManus
mesh_terms: D000818:Animals; D016572:Cyclosporine / Q000494:pharmacology; D006084:Graft Rejection / Q000175:diagnosis* / Q000473:pathology; D016027:Heart Transplantation; D007166:Immunosuppressive Agents / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous; D014185:Transplantation, Isogeneic
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine