ÜLSERATİF KOLİT HASTALARINDA HASTALIK AKTİVİTİTESİNİN DEĞERLENDİRİLMESİNDE GÖZ BULGULARI İLE KONVANSİYONEL AKTİVİTE BELİRTEÇLERİNİN KARŞILAŞTIRILMASI

Abstract

Ulcerative colitis is a systemic inflammatory disease that may lead to secondary effects on vascular structures due to chronic inflammation. The retina, which has a dense capillary network, can undergo various changes in its vascular structures through multiple mechanisms in the context of ulcerative colitis. With the widespread adoption of OCT-A imaging device, numerous studies investigating the relationship between disease activity and alterations in retinal vascular structures have been introduced. The objective of our study was to investigate whether variations in retinal vascular structures are correlated with conventional biomarkers in the assessment of disease activity.

In this context, patients with ulcerative colitis who presented to the Gastroenterology Clinic of Hacettepe University Faculty of Medicine Hospital between January and April 2024, along with volunteers of similar age and gender distribution without chronic diseases who presented to the Ophthalmology Clinic during the same period, were invited to participate in the study. 47 ulcerative colitis patients and 42 healthy volunteers were wellcomed/employed in the study. The ulcerative colitis patients were partitioned into two main groups: active (n=26) and in remission (n=21), based on the Mayo Activity Scoring system. In the Gastroenterology and Ophthalmology clinics, certain tests and examinations were conducted according to the respective departments' protocols. All participants underwent anterior and posterior segment eye examinations, and the retinal vascular structures and choroid were thoroughly assessed using Optical Coherence Tomography Angiography (OCT-A) and Optical Coherence Tomography (OCT) devices. According to the results attained in this particular study, patients with ulcerative colitis exhibited an enlargement in the Foveal Avascular Zone (FAZ) in both the superficial and deep capillary plexus compared to the healthy control group (p<0.05), along with a general decrease in vessel density and perfusion percentages. These findings could be attributed to the ischemic and atherosclerotic effects of systemic inflammation on retinal vascular structures. In the study, it was demonstrated that the non-specific inflammatory biomarkers, serum C-reactive protein (sC-RP) and erythrocyte sedimentation rate (ESR), were linearly and positively correlated with disease activity and severity (p<0,05). The active patient group showed an increase in the mean values of sC-RP (p=0,81) and ESR (p=0,02) compared to the remission group; we believe that the error margins would decrease with an increase in the number of participants and/or the severity of activation. However, there was no significant correlation between the metric data from ocular findings and disease activity or severity (p>0,05). This outcome may be attributed to the preservation of the blood-retina barrier, even during active disease. In this context, there is a need for more extensive research on newly conceptualized topics such as the blood-retina barrier and the gut-retina axis.

In the anterior segment examinations of the participants, there were no additional findings, such as a history of uveitis, that could potentially cause changes in the posterior segment vascular structures.

As a result of this study, we demonstrated that the association of variations in retinal vascular structures and the choroid with ulcerative colitis disease activity is not fervent compared to conventional biomarkers. In this context, monitoring serum levels of conventional biomarkers such as sC-RP and ESR will be more beneficial for assessing disease activity in the routine clinical follow-up of ulcerative colitis patients. Additionally, non-invasive imaging methods such as OCT-A and OCT can be used at regular intervals for early detection of ocular manifestations and hence protection of visual function from permanent damage in ulcerative colitis patients.