Feasibility of Gastrografin Use for Adhesive Small Bowel Obstruction in Low-Income Countries.

INTRODUCTION: Small bowel obstruction (SBO) is one of the most common causes for hospital admission in Ethiopia. The use of water-soluble contrast agents (WSCAs) such as Gastrografin to manage adhesive SBO can predict nonoperative resolution of SBO and reduce decision time to surgery and length of hospital stay. However, nothing is known about practice patterns and Gastrografin use in low-income settings. We sought to characterize current management practices, including use of WSCAs, as well as outcomes for patients with SBO in Addis Ababa, Ethiopia. METHODS: We conducted a mixed-methods study consisting of a survey of surgeons throughout Ethiopia and a retrospective record review at five public, tertiary care-level teaching hospitals in Addis Ababa. RESULTS: Of the 76 surgeons who completed the survey, 63% had heard of the use of WSCAs for SBO and only 11% used oral agents for its management. Chart review of 149 patients admitted with SBO showed the most common etiology was adhesion (39.6% of admissions), followed by small bowel volvulus (20.8%). Most patients (83.2%) underwent surgery during their admission. The most common diagnosis in patients who did not require surgery was also adhesion (68.0%), as well as for those who had surgery (33.9%), followed by small bowel volvulus (24.2%). CONCLUSIONS: The etiology of SBO in Ethiopia may be changing, with postoperative adhesions becoming more common than other historically more prevalent causes. Although a Gastrografin protocol as a diagnostic and potentially therapeutic aid for SBO is feasible in this population and setting, challenges can be anticipated, and future studies of protocol implementation and effectiveness are needed to further inform its utility in Ethiopia and other low-income and middle-income countries.

T95 nucleophosmin phosphorylation as a novel mediator and marker of regulated cell death in acute kidney injury.

The function of site-specific phosphorylation of nucleophosmin (NPM), an essential Bax chaperone, in stress-induced cell death is unknown. We hypothesized that NPM threonine 95 (T95) phosphorylation both signals and promotes cell death. In resting cells, NPM exclusively resides in the nucleus and T95 is nonphosphorylated. In contrast, phosphorylated T95 NPM (pNPM T95) accumulates in the cytosol after metabolic stress, in multiple human cancer cell lines following γ-radiation, and in postischemic human kidney tissue. Based on the T95 phosphorylation consensus sequence, we hypothesized that glycogen synthase kinase-3ß (GSK-3ß) regulates cytosolic NPM translocation by phosphorylating T95 NPM. In a cell-free system, GSK-3ß phosphorylated a synthetic NPM peptide containing T95. In vitro, bidirectional manipulation of GSK-3ß activity substantially altered T95 phosphorylation, cytosolic NPM translocation, and cell survival during stress, mechanistically linking these lethal events. Furthermore, GSK-3ß inhibition in vivo decreased cytosolic pNPM T95 accumulation in kidney tissue after experimental ischemia. In patients with acute kidney injury, both cytosolic NPM accumulation in proximal tubule cells and NPM-rich intratubular casts were detected in frozen renal biopsy tissue. These observations show, for the first time, that GSK-3ß promotes cell death partly by phosphorylating NPM at T95, to promote cytosolic NPM accumulation. T95 NPM is also a rational therapeutic target to ameliorate ischemic renal cell injury and may be a universal injury marker in mammalian cells.

Cross organelle stress response disruption promotes gentamicin-induced proteotoxicity.

Gentamicin is a nephrotoxic antibiotic that causes acute kidney injury (AKI) primarily by targeting the proximal tubule epithelial cell. The development of an effective therapy for gentamicin-induced renal cell injury is limited by incomplete mechanistic insight. To address this challenge, we propose that RNAi signal pathway screening could identify a unifying mechanism of gentamicin-induced cell injury and suggest a therapeutic strategy to ameliorate it. Computational analysis of RNAi signal screens in gentamicin-exposed human proximal tubule cells suggested the cross-organelle stress response (CORE), the unfolded protein response (UPR), and cell chaperones as key targets of gentamicin-induced injury. To test this hypothesis, we assessed the effect of gentamicin on the CORE, UPR, and cell chaperone function, and tested the therapeutic efficacy of enhancing cell chaperone content. Early gentamicin exposure disrupted the CORE, evidenced by a rise in the ATP:ADP ratio, mitochondrial-specific H2O2 accumulation, Drp-1-mediated mitochondrial fragmentation, and endoplasmic reticulum-mitochondrial dissociation. CORE disruption preceded measurable increases in whole-cell oxidative stress, misfolded protein content, transcriptional UPR activation, and its untoward downstream effects: CHOP expression, PARP cleavage, and cell death. Geranylgeranylacetone, a therapeutic that increases cell chaperone content, prevented mitochondrial H2O2 accumulation, preserved the CORE, reduced the burden of misfolded proteins and CHOP expression, and significantly improved survival in gentamicin-exposed cells. We identify CORE disruption as an early and remediable cause of gentamicin proteotoxicity that precedes downstream UPR activation and cell death. Preserving the CORE significantly improves renal cell survival likely by reducing organelle-specific proteotoxicity during gentamicin exposure.

Nucleophosmin Phosphorylation as a Diagnostic and Therapeutic Target for Ischemic AKI.

Background Ischemic AKI lacks a urinary marker for early diagnosis and an effective therapy. Differential nucleophosmin (NPM) phosphorylation is a potential early marker of ischemic renal cell injury and a therapeutic target.Methods Differential NPM phosphorylation was assessed by mass spectrometry in NPM harvested from murine and human primary renal epithelial cells, fresh kidney tissue, and urine before and after ischemic injury. The biologic behavior and toxicity of NPM was assessed using phospho-NPM mutant proteins that either mimic stress-induced or normal NPM phosphorylation. Peptides designed to interfere with NPM function were used to explore NPM as a therapeutic target.Results Within hours of stress, virtually identical phosphorylation changes were detected at distinct serine/threonine sites in NPM harvested from primary renal cells, tissue, and urine. A phosphomimic NPM protein that replicated phosphorylation under stress localized to the cytosol, formed monomers that interacted with Bax, a cell death protein, coaccumulated with Bax in isolated mitochondria, and significantly increased cell death after stress; wild-type NPM or a phosphomimic NPM with a normal phosphorylation configuration did not. Three renal targeted peptides designed to interfere with NPM at distinct functional sites significantly protected against cell death, and a single dose of one peptide administered several hours after ischemia that would be lethal in untreated mice significantly reduced AKI severity and improved survival.Conclusions These findings establish phosphorylated NPM as a potential early marker of ischemic AKI that links early diagnosis with effective therapeutic interventions.