Plasma endothelin-1 levels in patients with rotator cuff tear: a case-control study.

Background: Several recent studies have demonstrated that the alteration of tendon microcirculation is one of the main causes of rotator cuff degeneration and tear. The aim of this study was to assess if patients with a rotator cuff tear (RCT) exhibit altered levels of endothelin-1 (ET-1), a powerful vasoconstrictor that could play a key role in the pathogenesis of RCTs, as well as in other tendon structures. Methods: A case-control study was conducted on 103 participants, divided into 60 cases and 43 controls. A sample of peripheral venous blood was collected from each participant. Each sample underwent centrifugation to obtain plasma, which was then analyzed using a specific enzyme-linked immunosorbent assay (ELISA) kit for human ET-1. Results: A total of 54 cases and 25 controls were recruited. Initially, we compared the mean plasma concentration of ET-1 of the two study groups. Although there is a higher mean value in controls compared to cases, the difference is not statistically significant (P>0.05). Subsequently, we compared the mean values of ET-1 based on the severity of the tear. Twenty-four patients had a small RCT, and their mean concentration of ET-1 was of 88.39 pg/mL, eight patients had a large tear and a mean ET-1 concentration of 72.07 pg/mL, while twenty-two patients showed a massive tear and a mean concentration of ET-1 of 78.27 pg/mL. However, this difference in ET-1 concentration was not statistically significant (P>0.05). Conclusions: From the preliminary results obtained, we can observe that, in terms of plasma ET-1 concentration, there are no statistically significant differences between cases with rotator cuff rupture and controls. Given the current limitations of the study, we expect to further expand the sample size to verify if these preliminary results will be confirmed.