Capecitabine-Induced, Nonneutropenic Enterocolitis

Phenotypic Screening of Prospective Analgesics Among FDA-Approved Compounds using an iPSC-Based Model of Acute and Chronic Inflammatory Nociception

Classical target-based drug screening is low-throughput, largely subjective, and costly. Phenotypic screening based on in vitro models is increasingly being used to identify candidate compounds that modulate complex cell/tissue functions. Chronic inflammatory nociception, and subsequent chronic pain conditions, affect peripheral sensory neuron activity (e.g., firing of action potentials) through myriad pathways, and remain unaddressed in regard to effective, non-addictive management/treatment options. Here, a chronic inflammatory nociception model is demonstrated based on induced pluripotent stem cell (iPSC) sensory neurons and glia, co-cultured on microelectrode arrays (MEAs). iPSC sensory co-cultures exhibit coordinated spontaneous extracellular action potential (EAP) firing, reaching a stable baseline after ≈27 days in vitro (DIV). Spontaneous and evoked EAP metrics are significantly modulated by 24-h incubation with tumor necrosis factor-alpha (TNF-α), representing an inflammatory phenotype. Compared with positive controls (lidocaine), this model is identified as an "excellent" stand-alone assay based on a modified Z' assay quality metric. This model is then used to screen 15 cherry-picked, off-label, Food and Drug Administration (FDA)-approved compounds; 10 of 15 are identified as "hits". Both hits and "misses" are discussed in turn. In total, this data suggests that iPSC sensory co-cultures on MEAs may represent a moderate-to-high-throughput assay for drug discovery targeting inflammatory nociception.

Capecitabine-induced Gastrointestinal Injury Shows a Graft-Versus-Host Disease (GVHD)-like Pattern

Capecitabine is a commonly used oral chemotherapeutic agent. Gastrointestinal (GI) side effects are clinically well-known, however, the histopathologic changes have not been comprehensively studied. This study describes the largest case series (8 patients) characterizing the histopathology of capecitabine-induced GI injury. All patients were adults (median age: 64.5 y, range: 61 to 76 y) and there was gender parity. Patients were receiving treatment for malignancies of the colorectum (n=5), breast (n=1), pancreas (n=1), and appendix (n=1). All had GI symptoms, including 7 with diarrhea and abdominal pain and 1 with melena. Five of 8 (63%) showed graft-versus-host disease (GVHD)-like histologic changes in small intestinal and/or colonic biopsies characterized by crypt disarray and dropout, crypt atrophy, dilated crypts lined by attenuated epithelium, and increased crypt apoptosis. Neuroendocrine cell aggregates were present in 4 of 5 cases. Four of 5 showed patchy prominence in lamina propria eosinophils. One patient receiving concomitant radiation therapy had a small intestinal biopsy showing regenerative changes. Two patients had histologically unremarkable biopsies. On follow-up, capecitabine was discontinued or dose-reduced in all patients. Three of 5 patients with a GVHD-like pattern had clinical improvement, whereas 2 died shortly after biopsy. One with regenerative changes also had radiation dose reduction and improved clinically. Two with unremarkable biopsies improved symptomatically. In summary, capecitabine-related GI injury shows a GVHD-like pattern. Knowledge of this is important to confirm the diagnosis as patients typically improve with dose reduction or discontinuation of the drug.

Capecitabine-associated enterocolitis: Narrative literature review of a rare adverse event and a case presentation

Capecitabine is an oral 5-fluorouracil prodrug with antimetabolite activity commonly used in advanced colorectal and breast cancer. It presents with a generally good toxicity profile and most of the adverse events can be managed effectively. Enterocolitis is a rare, under-reported, but potentially fatal adverse event associated with capecitabine use. To the best of our knowledge, there are 21 cases of capecitabine-related enterocolitis reported in the literature. We herein present a narrative literature review of enteritis/colitis cases associated with capecitabine use, with highlight to the most common clinical presentation, common imaging and microscopic findings and management approach. We furthermore present a case of severe capecitabine-related enteritis.

Capecitabine induced colitis

Capecitabine is an oral prodrug to 5-fluorouracil and is commonly used in the treatment of advanced breast, colon and stomach cancer. While gastrointestinal toxicity is common, enterocolitis and ischemic colitis are uncommon complications and the histologic features of capecitabine in the colonic mucosa have not been previously described. We present a case of colitis attributed to capecitabine toxicity in a 45-year-old man undergoing treatment of metastatic gastroesophageal adenocarcinoma. Possible pathophysiologic mechanisms of capecitabine toxicity are discussed and the histologic effects on the colon are described.

Neutropenic enterocolitis, a growing concern in the era of widespread use of aggressive chemotherapy

Neutropenic enterocolitis (NEC) is a life-threatening disease with substantial morbidity and mortality, seen primarily in patients with hematologic malignancies. The frequency of NEC has increased with the widespread use of chemotherapeutic agents such as the taxanes, which cause severe gastrointestinal mucositis. Neutropenic patients with fever and abdominal symptoms (cramping, pain, distention, diarrhea, GI bleeding), should undergo evaluation of the abdomen for bowel wall thickening of >4 mm, the hallmark of NEC. Clostridium difficile infection should be ruled out, as well as other etiologies such as graft-versus-host disease. Complications include bacteremia, which is often polymicrobial, hemorrhage, and bowel wall perforation/abscess formation. Management includes bowel rest, correction of cytopathies and coagulopathies, and broad spectrum antibiotics and antifungal agents. Surgical intervention may be necessary to manage complications such as hemorrhage and perforation and should be delayed, if possible, until recovery from neutropenia.