Clinical significance of CTGF and Cry61 protein in extraocular muscles of strabismic patients

Purpose To investigate the relationship between clinical features and protein amounts of Cysteine-rich 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2), which are vital components and regulators of the extracellular matrix in resected muscles from strabismus surgery. Methods Strabismus patients who were diagnosed with horizontal concomitant strabismus or inferior oblique overaction (IOOA) and required extraocular muscles (EOMs) resection to correct eye position were included in this study. The protein amounts were measured by enzyme-linked immunosorbent assay (ELISA) in resected EOMs. Multivariable linear regression was used to investigate the associations, adjusting for gender, age (continuous), amblyopia, and disease duration. Results A total of 141 muscles (including 38 lateral, 81 medial rectus, and 22 inferior oblique muscles) from 128 patients were collected in this study. The amount of Cry61 and CTGF per millimeter was significantly negatively associated with deviation angle in intermittent exotropia patients (Cry61: β , − 1.44; 95%CI, − 2.79 to − 0.10, p = 0.035; CTGF: β , − 3.14; 95%CI, − 5.06 to − 1.22, p = 0.002). The same relationship was also detected in the partially accommodative and non-accommodative esotropia patients, although it was not statistically significant (Cry61: β , − 2.40; 95%CI, − 5.05 to 0.24; p = 0.073; CTGF: β , − 3.47; 95%CI, − 9.18 to 2.87; p = 0.269). The amount of Cry61 and CTGF per millimeter showed significant associations with the degree of IOOA ( p < 0.05). Conclusions Taken together, our results demonstrated a significant relationship between deviation angle and protein amount of Cry61 and CTGF and implied that Cry61 and CTGF may play important roles in modulation of EOM contractility, which provide new insights into strabismus pathogenesis.