Crosslinking and corneal cryotherapy in acanthamoeba keratitis -- a histological study.
OBJECTIVE
Acanthamoeba keratitis is rare, but difficult to treat. Penetrating keratoplasty is performed in therapy-resistant cases. Nevertheless, subsequent recurrences occur in 40 % of the cases. In addition to triple-topical therapy (polyhexamid, propamidinisoethionat, neomycin), treatment alternatives are corneal cryotherapy and/or crosslinking (CXL). The aim of our present histological study was to analyze the persistence of acanthamoebatrophozoites and cysts, the persistence of bacteria, and activation of keratocytes in corneas of acanthamoeba keratitis patients following corneal cryotherapy and/or CXL.


METHODS
We analyzed histologically corneal buttons (from penetrating keratoplasties) of nine patients with acanthamoeba keratitis, following corneal cryotherapy (two patients) or a combination of crosslinking and corneal cryotherapy (seven patients), using haematoxilin–eosin, periodic acid Schiff (PAS), Gram and alpha-smooth muscle actin (alpha-SMA) stainings.


RESULTS
Acanthamoeba trophozoites persisted in three corneas after cryotherapy and CXL. Cysts persisted in one of two corneas following corneal cryotherapy and in six of seven corneas after a combination of CXL and cryotherapy. One cornea showed positive Gram staining, but there were no alpha-SMA positive keratocytes in any of the corneas.


CONCLUSIONS
Crosslinking and corneal cryotherapy have only limited impact on killing of acanthamoeba trophozoites, cysts, or bacteria. Corneal cryotherapy and CXL did not stimulate myofibroblastic transformation of keratocytes.
Tobias
T
Hager
A
A
Hasenfus
T
T
Stachon
B
B
Seitz
N
N
Szentmáry
D000048:Acanthamoeba / Q000302:isolation & purification; D015823:Acanthamoeba Keratitis / Q000469:parasitology / Q000473:pathology / Q000628:therapy*; D000199:Actins / Q000378:metabolism; D000328:Adult; D000562:Amebiasis / Q000469:parasitology / Q000628:therapy*; D003315:Cornea / Q000378:metabolism / Q000469:parasitology*; D060527:Corneal Keratocytes / Q000378:metabolism; D003432:Cross-Linking Reagents; D017679:Cryotherapy; D015822:Eye Infections, Parasitic / Q000469:parasitology / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays
C541116:ACTA2 protein, human; D000199:Actins; D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D012256:Riboflavin