Vincristine and intestinal pseudo-obstruction in children: report of 5 cases, literature review, and suggested management

Anorectal Infections in Neutropenic Leukemia Patients: A Common Clinical Challenge

Anorectal infections in neutropenic leukemia patients are a significant and potentially life-threatening complication. The pathogenesis of this condition is not entirely understood and believed to be multifactorial, including mucosal injury as a result of cytotoxic drugs, profound neutropenia and impaired host defense. Establishing an early diagnosis is key and often made clinically on the basis of signs and symptoms, but also from imaging studies demonstrating perianal inflammation or fluid collection. The management of anorectal infections in neutropenic leukemia patients is not straightforward, as there are no well-conducted studies on this entity. This review seeks to provide a framework into the pathophysiology and clinical presentation of anorectal infections in neutropenic leukemia patients, propose a diagnostic approach and to discuss controversies in the management of this condition.

Downregulation of mesenteric afferent sensitivity following long-term systemic treatment of vincristine in mice

AIMS

Gastrointestinal paresthesia and dysmotility are common side effects of vincristine (VCR) chemotherapy, which have become one of the factors for dose reduction, therapy delay or discontinuation. However, the mechanism is not entirely clear, whether it is related to autonomic nerves injury remains unknown. Therefore, we aimed to study whether VCR-induced gastrointestinal toxicity is related to changes in mesenteric afferent activity.

METHODS

The effects of a single VCR stimulation and long-term systemic VCR treatment on mesenteric afferent activity were investigated by directly recording mesenteric afferent discharge in vitro.

RESULTS

Our results showed that a single VCR (0.001-1 μmol/L) stimulation obviously increased the spontaneous, chemically evoked and mechanically evoked discharge of jejunal and colonic mesenteric afferents. This kind of hypersensitivity of VCR could be blocked by capsazepine, a transient receptor potential vanilloid 1 (TRPV1) antagonist. For the mice treated with VCR (0.1 mg/kg/d, i.p.) for 14 days, the abdominal withdrawal reflex and writhing response scores were reduced. Meanwhile, the spontaneous discharge of colonic mesenteric afferents and the afferent response to VCR was downregulated, and the afferent sensitivity to chemical and mechanical stimulation was reduced. Moreover, the expression of TRPV1 in colon was decreased.

CONCLUSIONS

These results suggest that the direct stimulation by VCR increases the mesenteric afferent sensitivity by activating TRPV1, which may be the reason of VCR-induced abdominal pain; the long-term systemic treatment of VCR decreases mesenteric afferent sensitivity by reducing TRPV1, which may be the reason of VCR-induced constipation.

The phytohormone forchlorfenuron decreases viability and proliferation of malignant mesothelioma cells in vitro and in vivo

Malignant mesothelioma (MM) is one of the most aggressive cancer types with a patient’s life expectancy of typically less than one year upon diagnosis. The urgency of finding novel therapeutic approaches to treat mesothelioma is evident. Here we tested the effect of the plant-growth regulator forchlorfenuron (FCF), an inhibitor of septin function(s) in mammalian cells, on the viability and proliferation of MM cell lines, as well as other tumor cell lines derived from lung, prostate, colon, ovary, cervix and breast. Exposure to FCF strongly inhibited proliferation of human and mouse (most efficiently epithelioid) MM cells and all other tumor cells in a concentration-dependent manner and led to cell cycle arrest and cell death. The role of septin 7 (SEPT7), a presumably essential target of FCF in MM cells was confirmed by an shRNA strategy. FCF was robustly inhibiting tumor cell growth in vitro at low micromolar (IC₅₀: ≈20-60µM) concentrations and more promisingly also in vivo. Initial experiments with FCF analogous revealed the importance of FCF’s chloride group for efficient cell growth inhibition. FCF’s rather low systemic toxicity might warrant for an extended search for other related and possibly more potent FCF analogues to target MM and putatively other septin-dependent tumors.

Pseudo-obstruction, enteric dysmotility and irritable bowel syndrome

New diagnostic techniques have advanced our knowledge about the irritable bowel syndrome. The majority of patients that we believed to have a psychosomatic disorder have received other diagnoses explaining their symptoms. Endoscopy makes it possible to diagnose celiac disease before it leads to malnutrition and allows the detection of microscopic colitis as a cause of watery diarrhea. At the severe end of the symptom spectrum enteric dysmotility marks the border at which IBS ceases to be a functional disorder and becomes a genuine motility disorder. Joint hypermobility or Ehlers-Danlos syndrome is present in a substantial proportion of patients with enteric dysmotility. Chronic intestinal pseudo-obstruction is the end-stage of a large number of very rare disorders in which failed peristalsis is the common denominator. Nutritional needs and symptom control are essential in the management of pseudo-obstruction. Home parenteral nutrition is life saving in more than half of patients with chronic intestinal pseudo-obstruction.

Involvement of Cannabinoid Signaling in Vincristine-Induced Gastrointestinal Dysmotility in the Rat

Background: In different models of paralytic ileus, cannabinoid receptors are overexpressed and endogenous cannabinoids are massively released, contributing to gastrointestinal dysmotility. The antitumoral drug vincristine depresses gastrointestinal motility and a similar mechanism could participate in this effect. Therefore, our aim was to determine, using CB₁ and CB₂ antagonists, whether an increased endocannabinoid tone is involved in vincristine-induced gastrointestinal ileus.

Methods: First, we confirmed the effects of vincristine on the gut mucosa, by conventional histological techniques, and characterized its effects on motility, by radiographic means. Conscious male Wistar rats received an intraperitoneal injection of vincristine (0.1–0.5 mg/kg), and barium sulfate (2.5 ml; 2 g/ml) was intragastrically administered 0, 24, or 48 h later. Serial X-rays were obtained at different time-points (0–8 h) after contrast. X-rays were used to build motility curves for each gastrointestinal region and determine the size of stomach and caecum. Tissue samples were taken for histology 48 h after saline or vincristine (0.5 mg/kg). Second, AM251 (a CB₁ receptor antagonist) and AM630 (a CB₂ receptor antagonist) were used to determine if CB₁ and/or CB₂ receptors are involved in vincristine-induced gastrointestinal dysmotility.

Key results: Vincristine induced damage to the mucosa of ileum and colon and reduced gastrointestinal motor function at 0.5 mg/kg. The effect on motor function was particularly evident when the study started 24 h after administration. AM251, but not AM630, significantly prevented vincristine effect, particularly in the small intestine, when administered thrice. AM251 alone did not significantly alter gastrointestinal motility.

Conclusions: The fact that AM251, but not AM630, is capable of reducing the effect of vincristine suggests that, like in other experimental models of paralytic ileus, an increased cannabinoid tone develops and is at least partially responsible for the alterations induced by the antitumoral drug on gastrointestinal motor function. Thus, CB₁ antagonists might be useful to prevent/treat ileus induced by vincristine.

Severe Vincristine-induced Neuropathic Pain in a CYP3A5 Nonexpressor With Reduced CYP3A4/5 Activity: Case Study

PURPOSE

Peripheral neuropathy is a frequent vincristine-induced adverse effect. Vincristine is a substrate of P-glycoprotein and is metabolized by the cytochrome P-450 (CYP) 3A5 and 3A4 isoforms, with CYP3A5 contributing to 75% of the intrinsic clearance of vincristine. Alterations in the function of these proteins may lead to an increase in vincristine toxicity. CYP3A5 nonexpressor status has been associated with vincristine-induced peripheral neuropathy. The severity of neuropathy has been reported to be inversely correlated to vincristine metabolite concentrations. Recently, the presence of a mutation in the CEP72 gene, which encodes for a protein involved in microtubule formation, has also been associated with vincristine-induced peripheral neuropathy. However, a clear correlation between genetic polymorphisms and vincristine toxicity has not been established.

METHODS

Here we report the case of a 21-year old patient in whom severe neuropathic pain developed after vincristine treatment.

FINDINGS

The patient was a CYP3A5 nonexpressor and presented with reduced CYP3A4/5 functional activity, a likely reason for the occurrence of the adverse event, as genotyping showed that his status was wild type for the ABCB1 and CEP72 genes.

IMPLICATIONS

CYP phenotype and genotype may explain the occurrence of severe neuropathy in some patients treated with vincristine.

Bezoar in a Pediatric Oncology Patient Treated with Coca-Cola

A bezoar is a mass of indigestible material. Bezoars can present with a gradual onset of non-specific gastrointestinal symptoms including abdominal pain, nausea and vomiting. However, bezoars can result in more serious conditions such as intestinal bleeding or obstruction. Without quick recognition, particularly in susceptible individuals, the diagnosis and treatment can be delayed. Currently resolution is achieved with enzymatic dissolution, endoscopic fragmentation or surgery. We describe, to our knowledge, the first pediatric patient with lymphoma to have had a bezoar treated with Coca-Cola.

A case of severe toxicity during coadministration of vincristine and piperacillin: are drug transporters involved in vincristine hypersensitivity and drug-drug interactions?

Neurotoxicity is frequent with vincristine treatment, but severe autonomic neuropathy is rare. A decreased activity of drug transporters in the presence of an interacting drug may favor such events by increasing systemic or tissue exposure to the drug. We encountered severe autonomic neuropathy and cholestasis in a child receiving vincristine, after the introduction of piperacillin-tazobactam. A causality assessment of the adverse reaction identified the antibiotic as the most probable cause of the observation. The patient was heterozygous for several common polymorphisms of ABCC2 (multidrug-related protein-2), CYP3A5, and ABCB1 (multidrug-related protein-1, P-glycoprotein), but their role in the toxicity cannot be ascertained.

Pain in blood cancers

Patients with blood-related cancers (BRC) suffer from a substantial symptom burden, including several pain syndromes sustained by different causes and pathogenetic mechanisms. So, with regard to pain, a multifaceted clinical scenario may be observed in this setting. Indeed, pain may be correlated to disease itself, to disease-associated complications, to iatrogenic causes or may be due to unrelated clinical conditions. A close diagnostic procedure for the assessment of the underlying causes of the pain and of its pathogenetic mechanisms may direct the treatment approach which should be based on a multidisciplinary management and requires the integration of etiology-targeted interventions and painkilling drugs. The World Health Organization's three-step analgesic ladder for cancer pain relief can provide adequate pain control using oral drugs in most patients with BRC on pain, although more complex interventions may be necessary for many difficult-to-treat pain syndromes which are not infrequently encountered in this setting.

Two cases of paralitic ileus in onco-hematologic patients

Paralytic ileus is a severe complication resulting from a variety of disorders. It occurs most commonly in patients with serious underlying medical or surgical conditions. Prompt diagnosis and appropriate management may improve the outcome. We describe 2 cases of onco-hematologic patients who presented this complication after intensive chemotherapy.

Pain in malignant hematology

Pain is frequently experienced by patients with hematological malignancies, although it often receives little attention. Different underlying causes and mechanisms may sustain several pain syndromes in hematological malignant patients. Pain may be due to disease itself, to disease-related complications, to iatrogenic causes or may be associated with unrelated medical conditions. The management of pain in this setting requires a multidisciplinary approach, integrating analgesics and causal interventions. An accurate diagnostic assessment and the identification of the underlying causes and pathogenetic mechanisms may dictate the treatment approach. For most pain patients, the WHO's three-step analgesic scale for cancer pain relief can provide adequate relief with oral options, although difficult-to-treat pain syndromes, requiring a more complex treatment approach, may also be observed.