Richard M. Logan

Serum levels of NF-κB and pro-inflammatory cytokines following administration of mucotoxic drugs

Introduction:Alimentary tract (AT) mucositis is a serious complication of cancer treatment. Determining changes that occur in the AT can be difficult as invasive procedures are usually contraindicated in these patients. Changes in tissue levels of the transcription factor NF-κB and pro-inflammatory cytokines have been demonstrated. The aims of this study were to determine whether changes in serum levels of NF-κB, TNF, IL-1β and IL-6 following administration of different drugs predicted histological evidence of tissue damage.Materials and Methods:Female DA rats (n=243) were given a single dose of irinotecan (200mg/kg intraperitoneally), methotrexate (1.5mg/kg intramuscularly) or 5-fluorouracil (150mg/kg intraperitoneally) and killed 30, 60, 90 minutes, 2, 6, 12, 24, 48 or 72 hours later. Control rats received no treatment. Blood samples were taken via cardiac puncture and centrifuged at 5000 rpm to collect serum. Serum levels of NF-κB, and pro-inflammatory cytokines were measured by ELISA. Results:Changes in serum levels of NF-κB, TNF, IL-1β and IL-6 were observed following administration of each drug. These changes differed according to the drug administered. In most instances, peaks in serum levels occurred following initial histological changes, Although following MTX administration, serum IL-1β peaked before histological changes and following 5-FU administration, serum NF-κB, TNF, IL-1β and IL-6 all peaked before histological evidence of tissue damage.

Gastrointestinal Microflora and Mucins May Play a Critical Role in the Development of 5-Fluorouracil-Induced Gastrointestinal Mucositis:

5-Fluorouracil (5-FU) is a commonly used chemotherapy agent in clinical oncology practice. Two of its major side effects are mucositis and diarrhoea. The structure of mucins offers mucosal protection, and allows maintenance of intestinal flora by providing attachment sites and preventing bacterial overgrowth and/or penetration. The aim of this study was to investigate changes in mucin secretion and microflora following treatment with 5-FU. Female DA rats were given a single 150 mg/ kg i.p. dose of 5-FU. Rats were killed at various time points after treatment. Control rats received no treatment. Jejunum, colon and faecal samples were collected. Standard microbiological culture techniques were used to identify bacteria, and real-time PCR was used to quantify bacteria in faecal samples. Goblet cells and cavitated goblet cells (having undergone mucus exocytosis) were also counted. Statistical analysis was carried out using Kruskal-Wallis test, a non-parametric method of testing equality of group medians. Following treatment with 5-FU, we showed decreases in Clostridium spp., Lactobacillus spp. and Streptococcus spp., and an increase in Escherichia spp. in the jejunum. In the colon, 5-FU caused decreases in Enterococcus spp., Lactobacillus spp. and Streptococcus spp. Real-time PCR of faecal samples showed decreasing trends in Lactobacillus spp. and Bacteroides spp., and an increasing trend in E. coli. Significant increases (P < 0.05) were seen in Clostridium spp. and Staphylococcus spp. at 24 h. Goblet cell numbers decreased significantly in the jejunum from 24–72 h, with a significant increase in the percentage of cavitated goblet cells. In conclusion, 5-FU treatment causes significant changes in intestinal flora and mucin secretion in rats. These changes could result in systemic effects and, in particular, may contribute to the development of chemotherapy-induced mucositis.

Faecal microflora and β-glucuronidase expression are altered in an irinotecan-induced diarrhea model in rats

Objectives: Chemotherapy-induced diarrhea (CID) is a well recognized side effect of cancer treatment. However, the pathophysiology behind this debilitating side effect remains unclear. Irinotecan causes cholinergic and delayed onset diarrhea in patients, in which β-glucuronidase produced by gut bacteria is thought to be involved. Methods: Rats were treated with 200mg/kg irinotecan and killed at various time points up to 72 h. Rats were monitored for diarrhea. Sections were stained for β-glucuronidase expression, and faecal DNA was analysed using real time PCR. Results: Diarrhea occurred, as expected, following irinotecan treatment. β-glucuronidase expression increased in the jejunum and colon. Faecal flora changed quantitatively after treatment also, with increases in E. coli, Staphylococcus spp., and Clostridium spp. (all β-glucuronidase producing), and decreases in Lactobacillus spp., Bifidobacterium spp. (both beneficial bacteria), and Bacteroides spp. (β-glucuronidase producing, major component of intestinal flora). Conclusions: Irinotecan-induced diarrhea may be caused by an increase in β-glucuronidase producing bacteria. However, the increase in bacteria may also be caused by irinotecan, further exaggerating the toxicity of the drug, and emphasising the need for these specific bacteria to be therapeutically targeted for successful treatment regimens to be accomplished.

Emerging evidence on the pathobiology of mucositis

BackgroundConsiderable progress has been made in our understanding of the biological basis for cancer therapy-induced mucosal barrier injury (mucositis). The last formal review of the subject by MASCC/ISOO was published in 2007; consequently, an update is timely.MethodsPanel members reviewed the biomedical literature on mucositis pathobiology published between January 2005 and December 2011.ResultsRecent research has provided data on the contribution of tissue structure changes, inflammation and microbiome changes to the development of mucositis. Additional research has focused on targeted therapy-induced toxicity, toxicity clustering and the investigation of genetic polymorphisms in toxicity prediction. This review paper summarizes the recent evidence on these aspects of mucositis pathobiology.ConclusionThe ultimate goal of mucositis researchers is to identify the most appropriate targets for therapeutic interventions and to be able to predict toxicity risk and personalize interventions to genetically suitable patients. Continuing research efforts are needed to further our understanding of mucositis pathobiology and the pharmacogenomics of toxicity.

Irinotecan‐induced mucositis manifesting as diarrhoea corresponds with an amended intestinal flora and mucin profile

Chemotherapy‐induced diarrhoea is a major oncological problem, caused by the cytotoxic effects of cancer chemotherapy. Irinotecan is linked with severe mucositis and diarrhoea, the mechanisms of which remain poorly understood. Bacterial β‐glucuronidase is thought to be involved in the metabolism of irinotecan, implicating the intestinal flora. Intestinal mucins may also be implicated in the development of chemotherapy‐induced diarrhoea. Rats were treated with 200 mg/kg of irinotecan and killed at 96, 120 and 144 h. The rats were monitored for diarrhoea. Pathology and immunohistochemical staining was performed. The samples were cultured and faecal DNA was analysed using real‐time polymerase chain reaction. Severe diarrhoea was observed from 72 to 96 h. A decrease in body mass was also observed after treatment. Significant changes in goblet cell numbers (both complete and cavitated cells) were observed in the small and large intestines. Changes in MUC gene expression were observed in the small intestine only. Modifications were observed to the intestinal flora profile, especially Escherichia coli, and an increase in the expression of β‐glucuronidase was detected. In conclusion, irinotecan‐induced diarrhoea may be caused by an increase in some β‐glucuronidase‐producing bacteria, especially E. coli, exacerbating the toxicity of active metabolites. Accelerated mucous secretion and mucin release may also contribute to the delayed onset of diarrhoea.

Growth factors and cytokines in the prevention and treatment of oral and gastrointestinal mucositis

Goals of workGrowth factors and cytokines may be useful in preventing chemotherapy (CT)- and radiotherapy (RT)-induced oral and gastrointestinal mucositis. Two systematic reviews of the medical literature on growth factors and cytokines for the amelioration of CT- and RT-induced mucositis throughout the alimentary tract were performed by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society for Oral Oncology. The aim of these evidence-based scientific reviews was to critically evaluate the literature and create evidence-based guidelines for the use of growth factors and cytokines in the prevention or treatment of CT- and RT-induced mucositis.MethodThe two reviews covered articles on clinical trials from January 1966 through May 2002 and preclinical studies from June 2002 through May 2005, respectively. The systematic review process was based on a well-established method for evaluating scientific literature.Main resultsThe number of articles in the first review was 29. In the second review, 23 articles were evaluated, 14 preclinical and 9 clinical studies. It was concluded from the first review that there was no sufficient evidence to provide any recommendations for clinical practice guidelines regarding growth factors and cytokines. From the second review, a guideline could be presented recommending the use of recombinant human keratinocyte growth factor-1 (palifermin) to prevent oral mucositis in patients receiving high-dose CT and total body irradiation followed by stem cell transplantation for haematological malignancies. A guideline could also be provided suggesting that granulocyte macrophage colony-stimulating factor mouthwash not be used for the prevention of oral mucositis in the transplant setting with high-dose CT and autologous or allogeneic stem cell transplantation.ConclusionsThese systematic reviews have provided clarity and shown exciting new results. Further studies will provide new options for this debilitating side-effect of cancer therapy.

Oral Adverse Events Associated with Tyrosine Kinase and Mammalian Target of Rapamycin Inhibitors in Renal Cell Carcinoma: A Structured Literature Review

BACKGROUND Oral adverse events (OAEs) associated with multitargeted tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin inhibitors (mTORIs) are underestimated but frequent and novel presentations of mucosal manifestations. Because optimal antitumor activity requires maintaining the optimal dose, it is essential to avoid unintended treatment delays or interruptions. METHODS We review the reported prevalence and appearance of OAEs with TKIs and mTORIs and the current oral assessment tools commonly used in clinical trials. We discuss the correlations between OAEs and hand-foot skin reaction (HFSR) and rash. RESULTS The reported prevalence of oral mucositis/stomatitis of any grade is 4% for pazopanib, 28% for sorafenib, 38% for sunitinib, 41% for temsirolimus, and 44% for everolimus. Oral lesions associated with these agents have been reported to more closely resemble aphthous stomatitis than OM caused by conventional agents. In addition, these agents may result in symptoms such as oral mucosal pain, dysgeusia, and dysphagia, in the absence of clinical lesions. Because of these factors, OAEs secondary to targeted agents may be underreported. In addition, a correlation between OAEs and HFSR was identified. CONCLUSIONS OAEs caused by TKIs and mTORIs may represent dose-limiting toxicities, especially considering the fact that even low grades of OAEs may be troubling to the patient. We discuss how these novel AEs can be assessed because current mucositis assessment tools have limitations. Prospective studies investigating the pathogenesis, risk factors, and management of OAEs are needed in order to minimize the impact on patients health-related quality of life.

Pro-inflammatory cytokines play a key role in the development of radiotherapy-induced gastrointestinal mucositis

BackgroundMucositis is a toxic side effect of anti-cancer treatments and is a major focus in cancer research. Pro-inflammatory cytokines have previously been implicated in the pathophysiology of chemotherapy-induced gastrointestinal mucositis. However, whether they play a key role in the development of radiotherapy-induced gastrointestinal mucositis is still unknown. Therefore, the aim of the present study was to characterise the expression of pro-inflammatory cytokines in the gastrointestinal tract using a rat model of fractionated radiotherapy-induced toxicity.MethodsThirty six female Dark Agouti rats were randomly assigned into groups and received 2.5 Gys abdominal radiotherapy three times a week over six weeks. Real time PCR was conducted to determine the relative change in mRNA expression of pro-inflammatory cytokines IL-1β, IL-6 and TNF in the jejunum and colon. Protein expression of IL-1β, IL-6 and TNF in the intestinal epithelium was investigated using qualitative immunohistochemistry.ResultsRadiotherapy-induced sub-acute damage was associated with significantly upregulated IL-1β, IL-6 and TNF mRNA levels in the jejunum and colon. The majority of pro-inflammatory cytokine protein expression in the jejunum and colon exhibited minimal change following fractionated radiotherapy.ConclusionsPro-inflammatory cytokines play a key role in radiotherapy-induced gastrointestinal mucositis in the sub-acute onset setting.

Chemotherapy-Induced Diarrhea Is Associated with Changes in the Luminal Environment in the DA Rat

The microflora of the gastrointestinal tract (GIT) are a complex ecosystem, performing a number of beneficial functions. Irinotecan causes both early and late diarrhea, the latter possibly caused, in part, by changes in the microflora of the GIT. Female DA rats were given atropine subcutaneously, prior to a single 200 mg/kg intraperitoneal dose of irinotecan. Animals were monitored for diarrhea and killed at 30 and 60 mins, 2, 6, 12, 24, 48, and 72 hrs after chemotherapy administration. Control rats received no treatment. Fecal samples and stomach, jejunum, and colon samples were collected and stored at −70°C until required. Standard microbiological culture techniques were used to grow and isolate the flora. Biochemical tests were used to identify the bacteria. The level of growth was noted for relative comparison between time points and graded accordingly. Early diarrhea was observed in the rats from 2–6 hrs after treatment, after which time the diarrhea resolved. Late onset diarrhea was apparent 72 hrs after treatment. Changes were seen in the flora of the stomach, jejunum, colon and feces. The majority of microflora changes were seen 6, 12, and 24 hrs after treatment, with a relative increase or decrease in the presence of bacteria in comparison with control rats. In some rats bacteria were not observed at all time points, and different bacteria not seen in control animals were identified in rats treated with irinotecan. These changes were observed up to 72 hrs after treatment. In conclusion, irinotecan treatment causes changes in the flora of the stomach, jejunum, colon, and feces of rats and is associated with the development of diarrhea. These changes in flora may have systemic effects and in particular may contribute to the development of chemotherapy-induced mucositis.

Sjögren's syndrome: a review of aetiology, pathogenesis, diagnosis and management.

Sjögrens syndrome is a chronic autoimmune disease that affects many individuals within the community. Despite this, its exact aetiology and pathogenesis is still unclear. Sjögrens syndrome affects many organ systems in the body. However, for dental practitioners it is important to recognize the many oral and dental manifestations that are associated with the syndrome. In addition to these oral manifestations, this review will discuss the systemic manifestations of Sjögrens syndrome as well as the current understanding of factors that have a role in its aetiology and pathogenesis. Furthermore, this review will highlight the difficulties and complexities that are inherent in the diagnosis of Sjögrens syndrome and the important role that dental practitioners can play in the management of its oral manifestations. The effective management of oral manifestations and minimization of oral disease in patients with Sjögrens syndrome can result in improved quality of life for these patients.