[Serum Claudin-5 levels facilitate the early prediction of severe acute pancreatitis: a prospective observational study].

Objective: To investigate the value of early tight junction protein Claudin-5 levels in predicting the severity of acute pancreatitis (AP).

Methods: A prospective observational study was conducted, including patients diagnosed with AP and admitted to the Northern Jiangsu People's Hospital from December 1, 2021 to November 30, 2022. Eligible healthy volunteers were randomly selected to serve as healthy controls during the same period. Patients were classified into mild acute pancreatitis (MAP) group, moderate-severe acute pancreatitis (MSAP) group, and severe acute pancreatitis (SAP) group based on the 2012 Atlanta classification criteria. Patients with SAP were then divided into three subgroups of 1, 3, and 7 days based on the duration of hospitalization. Baseline data, such as gender, age, underlying disease, and probable etiology, was collected from all enrolled individuals. The enzyme-linked immunosorbent assay (ELISA) was employed to detect serum Claudin-5 levels in each cohort of enrollees. Data on additional serologic indicators, including hematocrit (HCT), albumin (Alb), serum Ca²⁺, C-reactive protein (CRP), and procalcitonin (PCT) levels, were obtained via the in-hospital test query system in each group of patients with AP. The modified Marshall score (mMarshall), modified CT severity index (mCTSI) score, bedside severity index of severity in acute pancreatitis (BISAP) score, and acute physiology and chronic health evaluation II (APACHE II) were recorded for each group of patients with AP. Differences in the above indicators between groups were analyzed and compared. Spearman's correlation method was employed to examine the relationship between Claudin-5 levels and each influential factor. The receiver operator characteristic curve (ROC curve) was plotted to analyze the predictive value of each influencing factor on SAP. Ridge regression was used to screen for independent risk factors for SAP.

Results: A total of 109 patients with AP were enrolled, comprising 66 in the MAP group, 15 in the MSAP group, and 28 in the SAP group. Additionally, 27 healthy volunteers were enrolled as the healthy control group. No statistically significant differences were observed in gender and age among the enrolled groups, and no statistically significant differences were identified among the three groups of patients with AP in terms of underlying disease and etiologic composition. As the disease progressed, serum Claudin-5 levels exhibited a notable increase across all AP patient groups, and they were all significantly higher than those in the healthy control group [ng/L: 888.58 (574.52, 1 141.59), 3 749.02 (2 784.93, 5 789.92), 4 667.81 (3 935.21, 7 315.66) vs. 291.13 (250.19, 314.75), all P < 0.05]. Subgroup analyses showed that as the disease duration prolonged, patients in the SAP group exhibited a notable decline in Claudin-5 levels at 3 days post-admission, compared with those at 1 day post-admission [ng/L: 2 052.59 (1 089.43, 4 006.47) vs. 4 667.81 (3 935.21, 7 315.66), P < 0.05]. Spearman correlation analysis showed that serum Claudin-5 levels in patients with AP were significantly positively correlated with CRP, PCT, HCT, and mMarshall, mCTSI, and BISAP scores (r values were 0.570, 0.525, 0.323, 0.774, 0.670, 0.652, all P < 0.001), and significantly negatively correlated with Alb (r = -0.394, P < 0.001). A significant trend was observed in patients with AP, with an increase of HCT levels and a decrease of Alb levels as the disease progressed (both P < 0.05). An improvement of aforementioned phenomena was observed in patients with SAP following treatment, indirectly indicating that serum Claudin-5 level was a positive indicator of vascular leakage. ROC curve analysis showed that serum Claudin-5 levels in patients with AP exhibited the highest accuracy for early prediction of SAP, with the area under the ROC curve (AUC) of 0.948. When serum Claudin-5 levels ≥2 997 ng/L, the sensitivity for early screening for SAP was 100% and the specificity was 88.89%. Multifactorial ridge regression analysis showed that serum Claudin-5 level, PCT and APACHE II score could be used as independent risk factors for early prediction of SAP (all P < 0.05).

Conclusions: Serum Claudin-5 levels facilitate early prediction of SAP and are strongly associated with inflammatory response and vascular leakage.