title: Cyclic Adenosine Monophosphate Activates Retinal Apolipoprotein A1 Expression and Inhibits Myopic Eye Growth.
abstract: OBJECTIVE
  Apolipoprotein A1 (ApoA1) has been shown to inhibit myopia development in chicks, but the underlying biological mechanism remains unknown. Because ApoA1 interacts with cyclic adenosine monophosphate (cAMP) in many cellular systems, we examined whether this interaction is important in myopia development.
  
  
  METHODS
  The nonmetabolizable cAMP analogue 8-Bromo-cAMP (8-Br-cAMP) was administered intravitreally to the right eyes of 8-day old chicks for 4 consecutive days. Control eyes received vehicle. Chicks in group 1 received 8-Br-cAMP (0.1 mM or 1 mM) and were fitted with -10 diopter (D) lenses on both eyes, whereas chicks in group 2 (0.1 mM 8-Br-cAMP) wore plano lenses over both eyes. The levels of retinal cAMP and ApoA1 were examined in another two groups of chicks wearing -10 D (group 3) and +10 D lenses (group 4) over their right eyes for 3 days, respectively (plano over left eyes).
  
  
  RESULTS
  The 8-Br-cAMP significantly inhibited development of lens-induced myopia (group 1: 0.1 mM versus vehicle: +1.71 ± 1.22 D versus -8.00 ± 2.19 D; 1 mM versus vehicle: +1.38 ± 1.34 D versus -9.96 ± 1.14 D, mean ± SEM, P < 0.01 for both); 1 mM, but not 0.1 mM 8-Br-cAMP increased expression of retinal ApoA1 levels in right eyes (P < 0.01). The 8-Br-cAMP had minimal effect on normal eye growth. Both retinal cAMP and ApoA1 levels were significantly increased only in hyperopic eyes (group 4).
  
  
  CONCLUSIONS
  The 8-Br-cAMP robustly inhibited development of lens-induced myopia. The increase in retinal ApoA1 observed in cAMP-treated and hyperopic eyes suggested a possible interplay between ApoA1 and cAMP in regulating eye growth.
authors.affiliation: Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong Special Administrative Region of China.
authors.forename: Rachel Ka Man
authors.initials: RK
authors.lastname: Chun
authors.affiliation: Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong Special Administrative Region of China.
authors.forename: Sze Wan
authors.initials: SW
authors.lastname: Shan
authors.affiliation: Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong Special Administrative Region of China.
authors.forename: Thomas Chuen
authors.initials: TC
authors.lastname: Lam
authors.affiliation: Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong Special Administrative Region of China.
authors.forename: Chun Lung
authors.initials: CL
authors.lastname: Wong
authors.affiliation: Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong Special Administrative Region of China.
authors.forename: King Kit
authors.initials: KK
authors.lastname: Li
authors.affiliation: Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong Special Administrative Region of China.
authors.forename: Chi Wai
authors.initials: CW
authors.lastname: Do
authors.affiliation: Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, Hong Kong Special Administrative Region of China 2State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, S.
authors.forename: Chi Ho
authors.initials: CH
authors.lastname: To
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016632:Apolipoprotein A-I / Q000096:biosynthesis*; D002645:Chickens; D000242:Cyclic AMP / Q000494:pharmacology*; D004195:Disease Models, Animal; D007908:Lens, Crystalline / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D009216:Myopia / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D012029:Refraction, Ocular / Q000502:physiology*; D012160:Retina / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
chemical_list: D016632:Apolipoprotein A-I; D000242:Cyclic AMP