TY - JOUR

T1 - Heritability of tear fluid cytokines in healthy twins

AU - Bjerager, Jakob

AU - Magnø, Morten

AU - Chen, Xiangjun

AU - Belmouhand, Mohamed

AU - Aass, Hans Christian D.

AU - Reppe, Sjur

AU - Heegaard, Steffen

AU - Larsen, Michael

AU - Utheim, Tor P.

N1 - Publisher Copyright: © 2024 Elsevier Inc.

PY - 2024

Y1 - 2024

N2 - Purpose: Ocular surface disease is common and it is associated with elevated concentration levels of cytokines in tear fluid. Studies of the normal variation in tear fluid inflammatory markers are lacking. New knowledge may help guide research into ocular surface disease biomarkers and therapeutics. Methods: In this prospective twin cohort study, healthy individuals were recruited from a population-based registry. Tear fluid was collected with the Schirmer test strips was submerged in phosphate buffered saline and stored at −80° before undergoing 27-cytokine multiplex immunoassay analysis. Broad-sense heritability (h2) of cytokine concentrations was analyzed. Results: 90 participants (23 monozygotic and 22 dizygotic twin pairs) were included. Data availability allowed for heritability analysis of 15 cytokines, and a h2 >50% was seen for 10 cytokines. A statistical power of >80% was achieved for heritability analyses of the cytokines interferon gamma induced protein 10 (h2 = 94.8%), eotaxin (89.8%), interleukin 7 (86.6%), interleukin 1β (82.2%) and monocyte chemoattractant protein 1 (68.2%). Conclusions: The tear fluid concentration of several analyzed cytokines was found to be highly heritable. A considerable amount of the inter-individual variation observed for the concentration of certain tear fluid cytokines can be linked to hereditary factors that cannot easily be modified by changing factors in the environment of patients. This suggests that a higher success in ocular surface disease drug discovery may be anticipated for drugs that have targets in specific populations, and points to the importance of emphasizing known preventive measures of ocular surface disease and examinations of close relatives of patients with ocular surface disease, such as dry eye disease.

AB - Purpose: Ocular surface disease is common and it is associated with elevated concentration levels of cytokines in tear fluid. Studies of the normal variation in tear fluid inflammatory markers are lacking. New knowledge may help guide research into ocular surface disease biomarkers and therapeutics. Methods: In this prospective twin cohort study, healthy individuals were recruited from a population-based registry. Tear fluid was collected with the Schirmer test strips was submerged in phosphate buffered saline and stored at −80° before undergoing 27-cytokine multiplex immunoassay analysis. Broad-sense heritability (h2) of cytokine concentrations was analyzed. Results: 90 participants (23 monozygotic and 22 dizygotic twin pairs) were included. Data availability allowed for heritability analysis of 15 cytokines, and a h2 >50% was seen for 10 cytokines. A statistical power of >80% was achieved for heritability analyses of the cytokines interferon gamma induced protein 10 (h2 = 94.8%), eotaxin (89.8%), interleukin 7 (86.6%), interleukin 1β (82.2%) and monocyte chemoattractant protein 1 (68.2%). Conclusions: The tear fluid concentration of several analyzed cytokines was found to be highly heritable. A considerable amount of the inter-individual variation observed for the concentration of certain tear fluid cytokines can be linked to hereditary factors that cannot easily be modified by changing factors in the environment of patients. This suggests that a higher success in ocular surface disease drug discovery may be anticipated for drugs that have targets in specific populations, and points to the importance of emphasizing known preventive measures of ocular surface disease and examinations of close relatives of patients with ocular surface disease, such as dry eye disease.

KW - Cytokines

KW - Dry eye disease

KW - Heritability

KW - Inflammation

KW - Ocular surface disease

U2 - 10.1016/j.jtos.2024.02.005

DO - 10.1016/j.jtos.2024.02.005

M3 - Journal article

C2 - 38387783

AN - SCOPUS:85187395257

VL - 32

SP - 145

EP - 153

JO - The Ocular Surface

JF - The Ocular Surface

SN - 1542-0124

ER -