Assessment of corneal and conjunctival metaplasia by impression cytology during the treatment of canine keratoconjunctivitis sicca

Abstract

The purpose of this study was to assess the condition of cells in the conjunctiva and corneal epithelium prior to and during cyclosporine- or tacrolimusbased treatment of keratoconjunctivitis sicca (KCS). The study was performed on 40 dogs with KCS. The dogs were divided into two groups of 20 animals each. In Group I, 0.75% cyclosporine eye drops were administered three times a day, while in Group II 0.02% tacrolimus eye drops were administered twice daily. Additionally, each group was subdivided into three subgroups based on the results of the Schirmer I tear test (STT I). Evaluation of cellular metaplasia in the cornea and the palpebral and bulbar conjunctiva based on the Nelson-Adams scale was performed by impression cytology using Millipore round filters (Millipore VSWP 01300 DA) of 25 μm pore diameter applied to the studied area. Ophthalmological and cytological examinations were performed prior to the treatment as well as after one and two months of therapy. In both groups, a decrease in Nelson-Adams values was observed, corresponding to the increasing STT values [R Spearman statistically significant correlation coefficient values between -0.75 (P < 0.001) and -0.45 (P < 0.01)]. The absence of goblet cells was observed in all dogs, regardless of the KCS stage. Goblet cells reappeared following both tacrolimus- and cyclosporine-based treatment in impression cytology specimens classified as 0 in the Nelson-Adams scale. The extent of corneal and conjunctival metaplasia in the course of tacrolimus- and cyclosporine-based treatment of KCS decreases with increasing STT values.

Dry-eye syndrome in Shih Tzu dog: Ocular surface clinical and morphological aspects in the different stages of keratoconjunctivitis sicca

“…Quantitative KCS in dogs is classified according to the STT-1 value as mild, moderate, and severe (Giuliano 2013). The disease has been widely studied in veterinary medicine (Marek & Podhorska 1995, Carter & Colitz 2002, Cullen et al 2005, Naranjo et al 2005, Sanchez et al 2007, Williams 2008, Lima et al 2014, Liu et al 2014, Radziejewski et al 2018, Silva et al 2018, Williams & Tighe 2018, Haeussler Jr. 2019, Vatnikov et al 2020. However, few studies considered its different degrees for evaluations (Balicki The variation in the clinical presentation of KCS in specific dog breeds has been little explored (Herrera et al 2007, Sanchez et al 2007, Kitamura et al 2019).…”

“…Thus, tests such as meniscometry, tear film break-up time (TBUT), meibometry, and vital dyes are used to evaluate tear quality (Williams & Griffiths 2017). In contrast, diagnostic aid exams in veterinary medicine have been advocated to increase the diagnostic quality and targeting of KCS treatment in dogs (Williams & Griffiths 2017, Radziejewski et al 2018, Haeussler Jr. 2019. Cytohistomorphological analyses of the ocular surface of KCS carrier animals demonstrate conjunctival inflammatory infiltrate, reduced goblet cell density, and squamous metaplasia (Marek & Podhorska 1995, Balicki et al 2011, Radziejewski et al 2018.…”

“…In contrast, diagnostic aid exams in veterinary medicine have been advocated to increase the diagnostic quality and targeting of KCS treatment in dogs (Williams & Griffiths 2017, Radziejewski et al 2018, Haeussler Jr. 2019. Cytohistomorphological analyses of the ocular surface of KCS carrier animals demonstrate conjunctival inflammatory infiltrate, reduced goblet cell density, and squamous metaplasia (Marek & Podhorska 1995, Balicki et al 2011, Radziejewski et al 2018. Moreover, studies that evaluated the ocular microbiota of dogs of different breeds with the disease indicate a higher contamination rate and opportunistic bacteria (Oria et al 2013, Pereira et al 2019a.…”

A review of diagnostic tests for qualitative and quantitative tear film deficiency in dogs

“…6 | of the conjunctival epithelium assessment of the conjunctiva can provide valuable information about the health status of the conjunctival epithelium, including the mucin-secreting goblet cells. 4,79 This can be achieved via minimally invasive techniques such as conjunctival impression cytology, 79,[121][122][123] or by collecting a biopsy specimen of the conjunctiva. 85,124 Conjunctival impression cytology is well described in humans, with many potential applications (e.g., diagnosing various ocular surface disorders, staging conjunctival squamous metaplasia, monitoring treatment effect, and identifying disease biomarkers) 79,125 ; however, this diagnostic tool has been reported only in a few veterinary studies to date.…”

“…85,124 Conjunctival impression cytology is well described in humans, with many potential applications (e.g., diagnosing various ocular surface disorders, staging conjunctival squamous metaplasia, monitoring treatment effect, and identifying disease biomarkers) 79,125 ; however, this diagnostic tool has been reported only in a few veterinary studies to date. [121][122][123][124] 6 | CONCLUSIONS Ocular surface homeostasis is complex and cannot be simply assessed with Schirmer tear test. The diagnosis, monitoring, and evaluation of the treatment effects for quantitative and qualitative tear film deficiencies require a variety of ocular surface diagnostic tests.…”