title: Assessment of Proteins Associated With Complement Activation and Inflammation in Maculae of Human Donors Homozygous Risk at Chromosome 1 CFH-to-F13B.
abstract: OBJECTIVE
  To determine the effects of chromosome 1 genotype and cigarette smoking on levels of complement activation and inflammation in the human macula.
  
  
  METHODS
  Donor macular tissue was stratified into three groups by diplotype at the AMD-associated CFH-to-F13B locus: homozygous "risk" (n = 9, 56-78 years), homozygous neutral (n = 2, 64-79 years), and homozygous "protective" (n = 6, 61-78 years) diplotype. Importantly, all donors were homozygous nonrisk at the ARMS2/HTRA1 locus, so that purely chromosome 1-directed pathways were examined. Immunohistochemistry was performed by using 14 antibodies, mostly against markers of complement and inflammation, followed by confocal microscopy and immunofluorescence quantification (all masked to donor status).
  
  
  RESULTS
  Donors homozygous risk at CFH-to-F13B exhibited significantly higher levels of terminal complement complex (TCC) in macular Bruch's membrane (BM; P = 0.03), choriocapillaris (CC; P = 0.04), and choriocapillaris intercapillary septa (CC IS; P = 0.03), compared to homozygous protected donors. Smoking was associated with increased TCC in BM (P = 0.05), CC IS (P = 0.03), and choroidal stroma (CS; P = 0.01), and with substantially elevated C-reactive protein (CRP) levels in RPE (P = 0.04), BM (P = 0.01), CC (P = 0.05), and CS (P = 0.05). Smoking was associated with higher levels of oxidative stress in macular RPE (P = 0.04) and CS (P = 0.01).
  
  
  CONCLUSIONS
  Genetic risk at the CFH-to-F13B locus was associated with higher levels of complement activation at the human macular RPE-choroid interface, as was cigarette smoking. Levels of CRP were substantially elevated in risk donors with smoking history. Examination of human macular tissue from donors with "pure" diplotypes allows assessment of AMD-associated pathways driven solely by CFH-to-F13B. These findings have important implications for identifying chromosome 1-directed pathways and therapeutic targets.
authors.affiliation: Center for Translational Medicine John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States 2Centre for Ophthalmology & Vision Science, Institute of Human Development, Faculty of Med.
authors.forename: Tiarnan D L
authors.initials: TD
authors.lastname: Keenan
authors.affiliation: Center for Translational Medicine John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States.
authors.forename: Marc
authors.initials: M
authors.lastname: Toso
authors.affiliation: Center for Translational Medicine John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States.
authors.forename: Chris
authors.initials: C
authors.lastname: Pappas
authors.affiliation: Center for Translational Medicine John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States.
authors.forename: Lisa
authors.initials: L
authors.lastname: Nichols
authors.affiliation: Centre for Ophthalmology & Vision Science, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester and Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Bishop
authors.affiliation: Center for Translational Medicine John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Hageman
mesh_terms: D000368:Aged; D016570:Bruch Membrane / Q000378:metabolism*; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D003167:Complement Activation / Q000235:genetics*; D017242:Complement Factor H / Q000235:genetics* / Q000378:metabolism; D015938:Complement Membrane Attack Complex / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D005260:Female; D005838:Genotype; D006720:Homozygote; D006801:Humans; D007150:Immunohistochemistry; D008268:Macular Degeneration / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D014019:Tissue Donors
chemical_list: D015938:Complement Membrane Attack Complex; D017242:Complement Factor H; D004247:DNA