Outcomes of drug-induced acute pancreatitis: a ten-year experience of an academic center

Thiopurines impair the apical plasma membrane expression of CFTR in pancreatic ductal cells via RAC1 inhibition

BACKGROUND AND AIMS

Thiopurine-induced acute pancreatitis (TIP) is one of the most common adverse events among inflammatory bowel disease patients treated with azathioprine (AZA), representing a significant clinical burden. Previous studies focused on immune-mediated processes, however, the exact pathomechanism of TIP is essentially unclear.

METHODS

To model TIP in vivo, we triggered cerulein-induced experimental pancreatitis in mice receiving a daily oral dose of 1.5 mg/kg AZA. Also, freshly isolated mouse pancreatic cells were exposed to AZA ex vivo, and acinar cell viability, ductal and acinar Ca²⁺ signaling, ductal Cl^- and HCO₃^- secretion, as well as cystic fibrosis transmembrane conductance regulator (CFTR) expression were assessed using microscopy techniques. Ras-related C3 botulinum toxin substrate (RAC1) activity was measured with a G-LISA assay. Super-resolution microscopy was used to determine protein colocalization.

RESULTS

We demonstrated that AZA treatment increases tissue damage in the early phase of cerulein-induced pancreatitis in vivo. Also, both per os and ex vivo AZA exposure impaired pancreatic fluid and ductal HCO₃^- and Cl^- secretion, but did not affect acinar cells. Furthermore, ex vivo AZA exposure also inhibited RAC1 activity in ductal cells leading to decreased co-localization of CFTR and the anchor protein ezrin, resulting in impaired plasma membrane localization of CFTR.

CONCLUSIONS

AZA impaired the ductal HCO₃^- and Cl^- secretion through the inhibition of RAC1 activity leading to diminished ezrin-CFTR interaction and disturbed apical plasma membrane expression of CFTR. We report a novel direct toxic effect of AZA on pancreatic ductal cells and suggest that the restoration of ductal function might help to prevent TIP in the future.

Isoliquiritigenin ameliorates doxorubicin-induced acute pancreatitis by inhibiting ROS production via modulation of Nrf2/HO-1 oxidative stress pathway

BACKGROUND

Several case studies have reported that doxorubicin (DOX) could induce acute pancreatitis, but no animal experiments have confirmed such side effect of DOX, and there is no specific treatment. Isoliquiritigenin (ISL) has a variety of pharmacological functions, including anti-inflammatory and antioxidant activities; however, the role and mechanism of ISL on DOX-induced acute pancreatitis (DAP) remain unclear.

AIM

To confirm whether doxorubicin (DOX) results in pancreatic tissue injury, and to determine the role and mechanism of isoliquiritigenin (ISL) in protecting against DOX-induced pancreatitis.

METHODS

Male ICR mice (25-30 g) were randomly divided into a control group (intraperitoneal injection of normal saline), DOX-DAP model group (intraperitoneal injection of DOX 10 mg/kg every other day), and ISL treatment group (DOX + ISL group; intraperitoneal injection of DOX 10 mg/kg every other day and intragastric administration of ISL 100 mg/kg per day), with 8 mice in each group. Pancreatic histopathology and scoring were performed 5 d after modeling. The expression of alpha amylase in pancreatic tissue was detected by immunohistochemistry. Immunofluorescence assay was used to detect ROS production in pancreatic tissue. Protein expression of Nrf2 and HO-1 in pancreatic tissue was detected by Western blot.

RESULTS

Compared with the control group, the mice in the DOX-DAP model group showed characteristic pathological damage, such as pancreatic tissue edema and inflammatory cells infiltration, with significantly increased histopathological scores (P < 0.001) and decreased expression of alpha amylase in the pancreas (P < 0.01). Compared with the DOX-DAP model group, the DOX + ISL group had significantly decreased histopathological scores (P < 0.05) and increased expression of alpha amylase in the pancreas (P < 0.05). ROS fluorescence staining and Western blot analysis showed that compared with the control group, ROS generation in pancreatic tissue in the DOX-DAP model group was significantly increased (P < 0.001), and the expression levels of Nrf2 and HO-1 proteins were slightly increased (P < 0.001). Compared with the DOX-DAP group, the DOX + ISL group had significantly decreased ROS levels in pancreatic tissuesed (P < 0.001), and significantly increased expression of Nrf2 and HO-1 proteins (P < 0.001).

CONCLUSION

DOX can cause pancreatic pathological damage in mice, which is mainly characterized by pancreatic tissue edema and inflammatory cells infiltration. ISL administration has a protective effect on DOX-induced pancreatitis by enhancing the antioxidant stress level in pancreatic tissue, which is expected to provide a new method for the prevention and treatment of drug-induced pancreatitis.