Idiopathic Small Bowel Diaphragm Disease Without Use of Non-steroidal Anti-inflammatory Drugs: A Case Report and Review of the Literature.

Small bowel diaphragm disease is a rare condition that is characterized by the presence of diaphragm-like strictures that causes intermittent or complete small bowel obstruction. Most cases are asymptomatic until presented with severe abdominal pain due to small bowel obstruction or diagnosed during anemia workup as a cause of occult gastrointestinal bleeding. Small bowel diaphragm disease is usually associated with long-term use of non-steroidal anti-inflammatory drugs (NSAIDs). Here, we present the case of a 50-year-old male with no history of NSAID use who presented with abdominal pain and iron deficiency anemia. He was postoperatively diagnosed with idiopathic small bowel diaphragm disease.

Parkin elimination of mitochondria is important for maintenance of lens epithelial cell ROS levels and survival upon oxidative stress exposure.

Age-related cataract is associated with oxidative stress and death of lens epithelial cells (LECs) whose survival is dependent on functional mitochondrial populations. Oxidative stress-induced depolarization/damage of LEC mitochondria results in increased reactive oxygen species (ROS) levels and cell death suggesting the need for a LEC mechanism to remove mitochondria depolarized/damaged upon oxidative stress exposure to prevent ROS release and LEC death. To date, a mechanism(s) for removal of depolarized/damaged LEC mitochondria has yet to be identified and the importance of eliminating oxidative stress-damaged mitochondria to prevent LEC ROS release and death has not been established. Here, we demonstrate that Parkin levels increase in LECs exposed to H2O2-oxidative stress. We establish that Parkin translocates to LEC mitochondria depolarized upon oxidative stress exposure and that Parkin recruits p62/SQSTM1 to depolarized LEC mitochondria. We demonstrate that translocation of Parkin results in the elimination of depolarized/damaged mitochondria and that Parkin clearance of LEC mitochondria is dependent on its ubiquitin ligase activity. Importantly, we demonstrate that Parkin elimination of damaged LEC mitochondria results in reduced ROS levels and increased survival upon oxidative stress exposure. These results establish that Parkin functions to eliminate LEC mitochondria depolarized/damaged upon oxidative stress exposure and that elimination of damaged mitochondria by Parkin is important for LEC homeostasis and survival. The data also suggest that mitochondrial quality control by Parkin could play a role in lens transparency.