The nature of cytotoxic drug-induced cell death in murine intestinal crypts

Edaravone Exerts Protective Effects on Mice Intestinal Injury without Interfering with the Anti-Tumor Effects of Radiation

The appropriate dosage of edaravone-a radioprotective agent-and its effect on tumors are unknown. This study evaluated the effects of edaravone on intestinal injuries and tumors in mice induced by whole body X-ray irradiation. Small intestinal mucositis was induced in C3H/HeNSlc mice using a single X-ray dose (15 Gy). Edaravone (15, 30, and 100 mg/kg) was administered 30 min before irradiation to evaluate its protective effect. After 3.5 days, the jejunum was removed and the histological changes were evaluated. Next, C3H/HeNSlc mice with squamous cell carcinoma VII tumors were provided the same single X-ray dose and 100 mg/kg edaravone; further, the tumors were immediately induced after irradiation. The tumor cell viability was detected using an in vivo-in vitro colony formation assay. We found that the intestinal colony-forming ability after irradiation was significantly higher in the 100 mg/kg edaravone group than that in the control group. Moreover, the apoptotic cells in the villi immunohistochemically stained with cleaved caspase-3 were significantly lower in the 100 mg/kg edaravone group than in the control group. We found no radioprotective effects of intraperitoneally inoculated edaravone in both hind legs on squamous cell carcinoma VII tumors. These findings suggest that 100 mg/kg edaravone exerts protective effects on small intestinal injuries without interfering with the antitumor effects of radiation.

Relationship between Chemotherapy-Induced Diarrhea and Intestinal Microbiome Composition

BACKGROUND AND AIM

Fluoropyrimidines (FPs) are key drugs in many chemotherapy regimens; however, recipients are often prone to diarrhea due to gastrointestinal toxicity. Disruption of the intestinal epithelial barrier function by FPs leads to dysbiosis, which may exacerbate intestinal epithelial cell damage as a secondary effect and trigger diarrhea. However, despite studies on chemotherapy-induced changes in the intestinal microbiome of humans, the relationship between dysbiosis and diarrhea is unclear. In this study, we aimed to investigate the relationship between chemotherapy-induced diarrhea and the intestinal microbiome.

METHODS

We conducted a single-center prospective observational study. Twenty-three patients who received chemotherapy, including FPs as first-line chemotherapy for colorectal cancer, were included. Stool samples were collected before the start of chemotherapy and after one cycle of treatment to analyze intestinal microbiome composition and perform PICRUSt predictive metagenomic analysis.

RESULTS

Gastrointestinal toxicity was observed in 7 of 23 patients (30.4%), diarrhea was observed in 4 (17.4%), and nausea and anorexia were observed in 3 (13.0%). In 19 patients treated with oral FPs, the α diversity of the microbial community decreased significantly following chemotherapy only in the diarrheal group. At the phylum level, the diarrheal group showed a significant decrease in the abundance of Firmicutes and a significant increase in the abundance of Bacteroidetes with chemotherapy (p = 0.013 and 0.011, respectively). In the same groups, at the genus level, Bifidobacterium abundance was significantly decreased (p = 0.019). In contrast, in the non-diarrheal group, Actinobacteria abundance increased significantly with chemotherapy at the phylum level (p = 0.011). Further, Bifidobacterium, Fusicatenibacter, and Dorea abundance significantly increased at the genus level (p = 0.006, 0.019, and 0.011, respectively). The PICRUSt predictive metagenomic analysis revealed that chemotherapy caused significant differences in membrane transport in KEGG pathway level 2 and in 8 KEGG pathway level 3, including transporters and oxidative phosphorylation in the diarrhea group.

CONCLUSION

Organic-acid-producing bacteria seem to be involved in diarrhea associated with chemotherapy, including FPs.

Characterization of a novel dual murine model of chemotherapy-induced oral and intestinal mucositis

Oral and intestinal mucositis are debilitating inflammatory diseases observed in cancer patients undergoing chemo-radiotherapy. These are devastating clinical conditions which often lead to treatment disruption affecting underlying malignancy management. Although alimentary tract mucositis involves the entire gastrointestinal tract, oral and intestinal mucositis are often studied independently utilizing distinct organ-specific pre-clinical models. This approach has however hindered the development of potentially effective whole-patient treatment strategies. We now characterize a murine model of alimentary tract mucositis using 5-Fluorouracil (5-FU). Mice were given 5-FU intravenously (50 mg/kg) or saline every 48 h for 2 weeks. Post initial injection, mice were monitored clinically for weight loss and diarrhea. The incidence and extent of oral mucositis was assessed macroscopically. Microscopical and histomorphometric analyses of the tongue and intestinal tissues were conducted at 3 interim time points during the experimental period. Repeated 5-FU treatment caused severe oral and intestinal atrophy, including morphological damage, accompanied by body weight loss and mild to moderate diarrhea in up to 77.8% of mice. Oral mucositis was clinically evident throughout the observation period in 88.98% of mice. Toluidine blue staining of the tongue revealed that the ulcer size peaked at day-14. In summary, we have developed a model reproducing the clinical and histologic features of both oral and intestinal mucositis, which may represent a useful in vivo pre-clinical model for the study of chemotherapy-induced alimentary tract mucositis and the development of preventative therapies.

α-Mangostin Nanoparticles Cytotoxicity and Cell Death Modalities in Breast Cancer Cell Lines

α-Mangostin (AMG) is a potent anticancer xanthone that was discovered in mangosteen (Garcinia mangostana Linn.). AMG possesses the highest opportunity for chemopreventive and chemotherapeutic therapy. AMG inhibits every step in the process of carcinogenesis. AMG suppressed multiple breast cancer (BC) cell proliferation and apoptosis by decreasing the creation of cancerous compounds. Accumulating BC abnormalities and their associated molecular signaling pathways promotes novel treatment strategies. Chemotherapy is a commonly used treatment; due to the possibility of unpleasant side effects and multidrug resistance, there has been substantial progress in searching for alternative solutions, including the use of plant-derived natural chemicals. Due to the limitations of conventional cancer therapy, nanotechnology provides hope for effective and efficient cancer diagnosis and treatment. Nanotechnology enables the delivery of nanoparticles and increased solubility of drugs and drug targeting, resulting in increased cytotoxicity and cell death during BC treatment. This review summarizes the progress and development of AMG’s cytotoxicity and the mechanism of death BC cells. The combination of natural medicine and nanotechnology into a synergistic capital will provide various benefits. This information will aid in the development of AMG nanoparticle preparations and may open up new avenues for discovering an effective BC treatment.

Animal models of chemotherapy-induced mucositis: translational relevance and challenges

Chemotherapy for cancer patients induces damaging tissue reactions along the epithelium of the gastrointestinal tract (GIT). This chemotherapy-induced mucositis (CIM) is a serious side effect of cytotoxic drugs, and several animal models of CIM have been developed, mainly in rodents and piglets, to help understand the progression of CIM and how to prevent it. Animal models allow highly controlled experimental conditions, detailed organ (e.g., GIT) insights, standardized, clinically relevant treatment regimens, and discovery of new biomarkers. Still, surprisingly few results from animal models have been translated into clinical CIM management and treatments. The results obtained from specific animal models can be difficult to translate to the diverse range of CIM manifestations in patients, which vary according to the antineoplastic drugs, dose, underlying (cancer) disease, and patient characteristics (e.g., age, genetics, and body constitution). Another factor that hinders the direct use of results from animals is inadequate collaboration between basic science and clinical science in relation to CIM. Here, we briefly describe CIM pathophysiology, particularly the basic knowledge that has been obtained from CIM animal models. These model studies have indicated potential new preventive and ameliorating interventions, including supplementation with natural bioactive diets (e.g., milk fractions, colostrum, and plant extracts), nutrients (e.g., polyunsaturated fatty acids, short-chain fatty acids, and glutamine), and growth factor peptides (e.g., transforming growth factor and glucagon-like peptide-2), as well as manipulations of the gut microbiota (e.g., prebiotics, probiotics, and antibiotics). Rodent CIM models allow well-controlled, in-depth studies of animals with or without tumors while pig models more easily make clinically relevant treatment regimens possible. In synergy, animal models of CIM provide the basic physiological understanding and the new ideas for treatment that are required to make competent decisions in clinical practice.

Apoptosis, Dysbiosis and Expression of Inflammatory Cytokines are Sequential Events in the Development of 5-Fluorouracil-Induced Intestinal Mucositis in Mice

The chemotherapeutic agent 5-fluorouracil (5-FU) causes intestinal mucositis with severe diarrhoea, but the pathogenesis is not fully understood. In this study, we investigated the pathogenic effects of 5-FU in mice, focusing on apoptosis, enterobacteria and inflammatory cytokines. Repeated administration of 5-FU caused severe intestinal mucositis on day 6, accompanied by diarrhoea and body-weight loss. TNF-α expression increased 1 day after exposure to the drug, and spiked a second time on day 4, at which point myeloperoxidase activity and IL-1β expression also increased. Apoptotic cells were observed in intestinal crypts only on day 1. 5-FU also induced dysbiosis, notably decreasing the abundance of intestinal Firmicutes while increasing the abundance of Bacteroidetes and Verrucomicrobia. Twice-daily co-administration of oral antibiotics significantly reduced the severity of intestinal mucositis and dysbiosis, and blocked the increase in myeloperoxidase activity and cytokine expression on day 6, without affecting apoptosis and TNF-α up-regulation on day 1. In cultured colonic epithelial cells, exposure to 5-FU also up-regulated TNF-α expression. Collectively, the data suggest that crypt apoptosis, dysbiosis and expression of inflammatory cytokines are sequential events in the development of intestinal mucositis after exposure to 5-FU. In particular, 5-FU appears to directly induce apoptosis via TNF-α and to suppress intestinal cell proliferation, thereby resulting in degradation of the epithelial barrier, as well as in secondary inflammation mediated by inflammatory cytokines.

Oral Administration of Surface-Deacetylated Chitin Nanofibers and Chitosan Inhibit 5-Fluorouracil-Induced Intestinal Mucositis in Mice

This study investigated the prophylactic effects of orally administered surface-deacetylated chitin nanofibers (SDACNFs) and chitosan against 5-fluorouracil (5-FU)-induced intestinal mucositis, which is a common side effect of 5-FU chemotherapy. SDACNFs and chitosan abolished histological abnormalities associated with intestinal mucositis and suppressed hypoproliferation and apoptosis of intestinal crypt cells. These results indicate that SDACNF and chitosan are useful agents for preventing mucositis induced by anti-cancer drugs.

Both the anti- and pro-apoptotic functions of villin regulate cell turnover and intestinal homeostasis

In the small intestine, epithelial cells are derived from stem cells in the crypts, migrate up the villus as they differentiate and are ultimately shed from the villus tips. This process of proliferation and shedding is tightly regulated to maintain the intestinal architecture and tissue homeostasis. Apoptosis regulates both the number of stem cells in the crypts as well as the sloughing of cells from the villus tips. Previously, we have shown that villin, an epithelial cell-specific actin-binding protein functions as an anti-apoptotic protein in the gastrointestinal epithelium. The expression of villin is highest in the apoptosis-resistant villus cells and lowest in the apoptosis-sensitive crypts. In this study we report that villin is cleaved in the intestinal mucosa to generate a pro-apoptotic fragment that is spatially restricted to the villus tips. This cleaved villin fragment severs actin in an unregulated fashion to initiate the extrusion and subsequent apoptosis of effete cells from the villus tips. Using villin knockout mice, we validate the physiological role of villin in apoptosis and cell extrusion from the gastrointestinal epithelium. Our study also highlights the potential role of villin’s pro-apoptotic function in the pathogenesis of inflammatory bowel disease, ischemia-reperfusion injury, enteroinvasive bacterial and parasitic infections.

Cell proliferation within small intestinal crypts is the principal driving force for cell migration on villi

The functional integrity of the intestinal epithelial barrier relies on tight coordination of cell proliferation and migration, with failure to regulate these processes resulting in disease. It is not known whether cell proliferation is sufficient to drive epithelial cell migration during homoeostatic turnover of the epithelium. Nor is it known precisely how villus cell migration is affected when proliferation is perturbed. Some reports suggest that proliferation and migration may not be related while other studies support a direct relationship. We used established cell-tracking methods based on thymine analog cell labeling and developed tailored mathematical models to quantify cell proliferation and migration under normal conditions and when proliferation is reduced and when it is temporarily halted. We found that epithelial cell migration velocities along the villi are coupled to cell proliferation rates within the crypts in all conditions. Furthermore, halting and resuming proliferation results in the synchronized response of cell migration on the villi. We conclude that cell proliferation within the crypt is the primary force that drives cell migration along the villus. This methodology can be applied to interrogate intestinal epithelial dynamics and characterize situations in which processes involved in cell turnover become uncoupled, including pharmacological treatments and disease models.—Parker, A., Maclaren, O. J., Fletcher, A. G., Muraro, D., Kreuzaler, P. A., Byrne, H. M., Maini, P. K., Watson, A. J. M., Pin, C. Cell proliferation within small intestinal crypts is the principal driving force for cell migration on villi.

Mechanism-based management for mucositis: option for treating side effects without compromising the efficacy of cancer therapy

Mucositis is a major side effect induced by chemotherapy and radiotherapy. Although mucositis is a leading cause of morbidity and mortality in cancer patients, management is largely limited to controlling symptoms, and few therapeutic agents are available for treatment. Since mucositis could be inhibited by the modulation of radiotherapy- or chemotherapy-induced pathways independently of cancer treatment, there is an opportunity for the development of more targeted therapies and interventions. This article examined potential therapeutic agents that have been investigated for the prevention and/or inhibition of mucositis induced by conventional chemotherapy and radiotherapy. They can be classified according to their mechanisms of action: scavenging reactive oxygen species, inhibition of specific cytokine production or inflammation, and inhibition of apoptosis. These early events may be good target pathways for preventing the pathogenesis of mucositis. Considering that both cancer therapy and therapeutic agents for mucositis act on both normal and cancer cells, agents that inhibit mucositis should act through mechanisms that selectively protect normal cells without compromising cancer treatment. Therefore, mechanism-based guidance for the treatment of mucositis is critical to prevent risky treatments for cancer patients and to relieve detrimental side effects effectively from cancer therapy.

A diarylpentanoid curcumin analog exhibits improved radioprotective potential in the intestinal mucosa

PURPOSE

To best enhance the effects of radiotherapy, it is important to minimize adverse events, including free radical-induced intestinal cell damage. Given the threat of nuclear power plant accidents or nuclear terrorism, there is an urgent need for radioprotectants to counteract the radiation-induced toxicity and/or injuries. Curcumin exhibits protective effects against gamma irradiation; however, its in vivo efficacy is decreased due to the low bioavailability. We examined the radioprotective effect of a newly synthesized curcumin analog, GO-Y031, on 11-Gy X-ray-induced intestinal mucosal damage in mice.

MATERIALS AND METHODS

The radioprotection experiments were conducted by using C57BL/6J or Jcl:ICR mice. Molecules related to radiation damage, including p53, Bax, Bcl-2, cleaved caspase-3, and reactive carbonyl species (RCS), were investigated immunohistochemically.

RESULTS

GO-Y031 protected against crypt hypoplasia relative to a mock treatment at 0.5% (weight/weight); the number of crypts were 11.00 ± 2.00/circumference (mm) in treated versus 6.86 ± 0.99/mm in mock-treated C57BL/6 mice (p = 0.0079). GO-Y031 also reduced the levels of RCS, p53, and cleaved caspase-3 accumulation in the irradiated intestinal cells.

CONCLUSIONS

GO-Y031 suppresses the accumulation of RCS and apoptosis-related molecules in irradiated cells. This compound may be a good primary radioprotective compound.

Dark Agouti rat model of chemotherapy-induced mucositis: establishment and current state of the art

Mucositis is a major oncological problem. The entire gastrointestinal and genitourinary tract and also other mucosal surfaces can be affected in recipients of radiotherapy, and/or chemotherapy. Major progress has been made in recent years in understanding the mechanisms of oral and small intestinal mucositis, which appears to be more prominent than colonic damage. This progress is largely due to the development of representative laboratory animal models of mucositis. This review focuses on the development and establishment of the Dark Agouti rat mammary adenocarcinoma model by the Mucositis Research Group of the University of Adelaide over the past 20 years to characterize the mechanisms underlying methotrexate-, 5-fluorouracil-, and irinotecan-induced mucositis. It also aims to summarize the results from studies using different animal model systems to identify new molecular and cellular markers of mucositis.

Saireito (TJ-114), a Japanese traditional herbal medicine, reduces 5-fluorouracil-induced intestinal mucositis in mice by inhibiting cytokine-mediated apoptosis in intestinal crypt cells

Clinical chemotherapy frequently causes intestinal mucositis as a side effect, which is accompanied by severe diarrhea. We recently showed that the cytokine-mediated apoptotic pathway might be important for the development of intestinal mucositis induced by 5-fluorouracil (5-FU). Saireito, the traditional Japanese herbal (Kampo) medicine, is widely used to treat diarrhea and various inflammatory diseases in Japan. In the present study, we investigated the effect of saireito on 5-FU-induced intestinal mucositis in mice, especially in relation to apoptosis in the intestinal crypt. Male C57BL/6 mice were given 5-FU (50 mg/kg), i.p. once daily for 6 days. Intestinal mucositis was evaluated histochemically. Saireito (100–1000 mg/kg) was administered p.o. twice daily for 6 days. Repeated 5-FU treatment caused severe intestinal mucositis including morphological damage, which was accompanied by body weight loss and diarrhea. Daily administration of saireito reduced the severity of intestinal mucositis in a dose-dependent manner. Body weight loss and diarrhea during 5-FU treatment were also significantly attenuated by saireito administration. The number of apoptotic and caspase-3-activated cells in the intestinal crypt was increased, and was accompanied by up-regulated tumor necrosis factor (TNF)-α and interleukin (IL)-1β mRNA within 24 h of the first 5-FU injection. However, all of these measures were significantly lower after saireito administration. These results suggest that saireito attenuates 5-FU-induced intestinal mucositis. This action may come from the reduction of apoptosis in the intestinal crypt via suppression of the up-regulation of inflammatory cytokines. Therefore, saireito may be clinically useful for the prevention of intestinal mucositis during cancer chemotherapy.

Activation of p38-MAPK by CXCL4/CXCR3 axis contributes to p53-dependent intestinal apoptosis initiated by 5-fluorouracil

Chemotherapy-induced mucositis (CIM) is a major does limiting side-effect of chemoagents such as 5-fluorouracil (5-FU). Molecules involved in this disease process are still not fully understood. We proposed that the homeostatically regulated genes during CIM may participate in the disease. A cluster of such genes were previously identified by expression gene-array from the mouse jejunum in 5-FU-induced mucositis model. Here, we report that CXCL4 is such a homeostatically regulated gene and serves as a new target for the antibody treatment of CIM. CXCL4 and its receptor CXCR3 were confirmed at both the gene and protein levels to be homeostatically regulated during 5-FU-induced mucositis. Using of CXCL4 neutralizing monoclonal antibody (CXCL4mab) decreased the incidence, severity, and duration of the chemotherapy-induced diarrhea, the major symptom of CIM, in a 5-FU mouse CIM model. Mechanistically, CXCL4mab reduced the apoptosis of the crypt epithelia by suppression of the 5-FU-induced expression of p53 and Bax through its receptor CXCR3. The downstream signaling pathway of CXCL4 in activation of the epithelial apoptosis was identified in an intestinal epithelial cell line (IEC-6). CXCL4 activated the phosphorylation of p38 MAPK, which mediated the stimulated expression of p53 and Bax, and resulted in the ultimate activation of Caspase-8, -9, and -3. Taken together, activation of CXCL4 expression by 5-FU in mice participates in 5-FU-induced intestinal mucositis through upregulation of p53 via activation of p38-MAPK, and CXCL4mab is potentially beneficial in preventing CIM in the intestinal tract.

The colon: from banal to brilliant

The colon serves as the habitat for trillions of microbes, which it must maintain, regulate, and sequester. This is managed by what is termed the mucosal barrier. The mucosal barrier separates the gut flora from the host tissues; regulates the absorption of water, electrolytes, minerals, and vitamins; and facilitates host-flora interactions. Colonic homeostasis depends on a complex interaction between the microflora and the mucosal epithelium, immune system, vasculature, stroma, and nervous system. Disruptions in the colonic microenvironment such as changes in microbial composition, epithelial cell function/proliferation/differentiation, mucus production/makeup, immune function, diet, motility, or blood flow may have substantial local and systemic consequences. Understanding the complex activities of the colon in health and disease is important in drug development, as xenobiotics can impact all segments of the colon. Direct and indirect effects of pharmaceuticals on intestinal function can produce adverse findings in laboratory animals and humans and can negatively impact drug development. This review will discuss normal colon homeostasis with examples, where applicable, of xenobiotics that disrupt normal function.

5-HT₃ receptor antagonists ameliorate 5-fluorouracil-induced intestinal mucositis by suppression of apoptosis in murine intestinal crypt cells

BACKGROUND AND PURPOSE

Chemotherapeutic agents, including 5-fluorouracil (5-FU), frequently cause intestinal mucositis resulting in severe diarrhoea and morphological mucosal damage. 5-HT₃ receptor antagonists are clinically effective in the treatment of nausea and emesis during cancer chemotherapy. Therefore we here have examined the effects of 5-HT₃ receptor antagonists on 5-FU-induced intestinal mucositis in mice.

EXPERIMENTAL APPROACH

Intestinal mucositis was induced in male C57BL/6 mice by daily administration of 5-FU (50 mg·kg⁻¹) for 5 days. Effects of 5-HT₃ receptor antagonists, ramosetron (0.01-0.1 mg·kg⁻¹) and ondansetron (5 mg·kg⁻¹), on the accompanying histology, cytokine production and apoptosis were assessed.

KEY RESULTS

Continuous administration of 5-FU to mice caused severe intestinal mucositis, which was histologically characterized by the shortening of villi and destruction of intestinal crypts, accompanied by body weight loss and diarrhoea. Daily ramosetron administration dose-dependently reduced the severity of intestinal mucositis, body weight loss and diarrhoea. Similar beneficial effects were observed with ondansetron. The number of apoptotic, caspase-3- and caspase-8-activated cells increased 24 h after the first 5-FU administration, and these responses were reduced by ramosetron. The up-regulation of TNF-α, IL-1β and IL-6 following 5-FU treatment was also attenuated by ramosetron.

CONCLUSIONS AND IMPLICATIONS

5-HT₃ receptor antagonists ameliorated 5-FU-induced intestinal mucositis in mice, and this action could result from suppression of apoptotic responses in the intestinal crypt cells via inhibition of cytokine expression. Thus, 5-HT₃ receptor antagonists may be useful for preventing not only nausea and emesis but also intestinal mucositis during 5-FU chemotherapy.

Potential role of the NADPH oxidase NOX1 in the pathogenesis of 5-fluorouracil-induced intestinal mucositis in mice

Although NADPH oxidase 1 (NOX1) has been shown to be highly expressed in the gastrointestinal tract, the physiological and pathophysiological roles of this enzyme are not yet fully understood. In the present study, we investigated the role of NOX1 in the pathogenesis of intestinal mucositis induced by the cancer chemotherapeutic agent 5-fluorouracil (5-FU) in mice. Intestinal mucositis was induced in Nox1 knockout (Nox1KO) and littermate wild-type (WT) mice via single, daily administration of 5-FU for 5 days. In WT mice, 5-FU caused severe intestinal mucositis characterized by a shortening of villus height, a disruption of crypts, a loss of body weight, and diarrhea. In Nox1KO mice, however, the severity of mucositis was significantly reduced, particularly with respect to crypt disruption. The numbers of apoptotic caspase-3- and caspase-8-activated cells in the intestinal crypt increased 24 h after the first 5-FU administration but were overall significantly lower in Nox1KO than in WT mice. Furthermore, the 5-FU-mediated upregulation of TNF-α, IL-1β, and NOX1 and the production of reactive oxygen species were significantly attenuated in Nox1KO mice compared with that in WT mice. These findings suggest that NOX1 plays an important role in the pathogenesis of 5-FU-induced intestinal mucositis. NOX1-derived ROS production following administration of 5-FU may promote the apoptotic response through upregulation of inflammatory cytokines.

In vitro mesenchymal stem cell differentiation after mechanical stimulation

OBJECTIVES

Mesenchymal stem cells (MSC) are multipotent cells capable of differentiating into adipocytic, chondrocytic and osteocytic lineages on suitable stimulation. We have hypothesized that mechanical loading may influence MSC differentiation and alter their phenotype accordingly.

MATERIALS AND METHODS

Mouse bone marrow-derived MSC were established in vitro by differential adherence to plastic culture plates and grown in low glucose medium with 10% foetal calf serum and growth factors. Cells grew out and were subcultured up to 20 times. Differentiation protocols were followed for several cell lineages. Clones with trilineage potential were seeded in type I collagen gels and incubated in a tensioning force bioreactor and real-time cell-derived forces were recorded. Gels were fixed and sectioned for light and electron microscopy.

RESULTS

Cell monolayers of parent and cloned mouse bone marrow-derived MSC differentiated into adipocytes, osteocytes and chondrocytes, but not into cardiomyocytes, myotubes or neuronal cells. When cast into type I collagen gels and placed in tensioning bioreactors, MSC differentiated into fibroblast-like cells typical of tissue stroma, and upregulated α-smooth muscle actin, but rarely upregulated desmin. Electron microscopy showed collagen and elastin fibre synthesis into the matrix.

CONCLUSIONS

These experiments confirmed that MSC cell fate choice depends on minute, cell-derived forces. Applied force could assist in commercial manufacture of cultured bio-engineered prostheses for regenerative medicine as it mimics tissue stresses and constitutes a good model for development of tissue substitutes.

Interleukin-1 receptor antagonist reduced apoptosis and attenuated intestinal mucositis in a 5-fluorouracil chemotherapy model in mice

PURPOSE

The aim of this study was to investigate the relationship between changes in IL-1β expression and intestinal apoptosis after chemotherapy. And we further determine whether interleukin-1 receptor antagonist (IL-1Ra) reduces apoptosis in vivo after 5-fluorouracil (5-FU) chemotherapy in the small intestine.

METHODS

Intestinal mucositis was induced in mice by intraperitoneal injection of a single dose of 5-FU (200 mg/kg). IL-1Ra (1 mg/kg) was injected subcutaneously twice daily after 5-FU injection. 5-FU-induced intestinal apoptosis was detected by TUNEL assay. The expression of IL-1β induced by 5-FU in local intestinal tissue was examined by RT-PCR and immunohistochemistry. Assessment of 5-FU-induced mucositis (histology, diarrhea scores, bowel weight) was performed. The apoptosis-related proteins were investigated by western blotting analysis. The proliferation of intestine was examined by immunohistological staining of PCNA. Viability of IEC-6 cells was determined using the CCK-8 assay. The apoptosis of IEC-6 cells was examined by Hoechst 33342 staining.

RESULTS

The variation of IL-1β expression induced by 5-FU was in accordance with the changes in intestinal apoptosis. Administration of IL-1Ra could block the destructive effect of IL-1β and reduce apoptosis in the small intestinal crypt after chemotherapy. The protection against apoptosis was in accordance with the reduction of the up-regulation of Bax and caspase 3 and the elimination of the down-regulation of Bcl-2 and Bcl-xL. Moreover, IL-1Ra attenuated the severity of intestinal mucositis induced by 5-FU and enhanced intestinal crypt proliferation. In vitro experiments showed that IL-1Ra suppressed apoptosis and increased cell viability in enterocyte IEC-6 cells treated with 5-FU. Additionally, IL-1Ra did not affect the chemotherapeutic effect of 5-FU in tumor CT-26 xenograft mice.

CONCLUSIONS

Our studies elucidate that IL-1β is quite possibly involved in and mediated the course of intestinal apoptosis after 5-FU chemotherapy. Administered with IL-1Ra protects mice against intestinal apoptosis induced by 5-FU, relieves mucosal impairment of the small intestine, and facilitates the recovery of the intestinal mucosa. IL-1Ra treatment offers a novel promising strategy for the prevention and cure of chemotherapy-induced intestinal mucositis in clinical practice.

Update on esophagitis: controversial and underdiagnosed causes

CONTEXT

Esophagitis is a common cause of symptoms for which patients seek the advice of a physician. Esophagitis of differing etiologies often demonstrate overlapping histopathologic features, making their distinction difficult. This is especially true in esophageal disorders associated with increased numbers of intraepithelial eosinophils, some of which have just recently been recognized.

OBJECTIVE

This review discusses the important clinical and pathologic features of the 2 most common disorders associated with esophageal eosinophilic infiltrates--reflux esophagitis and eosinophilic esophagitis--with special emphasis on features that allow the surgical pathologist to distinguish between these disorders. The various forms of drug-induced esophagitis are also discussed because these are frequently underrecognized by pathologists.

DATA SOURCES

Data were extracted from articles identified through PubMed-based research. Histologic figures have been taken from the personal case collection of the author.

CONCLUSIONS

Reflux and eosinophilic esophagitis demonstrate overlapping histologic features, which may make their distinction difficult. Drug-induced esophagitis is probably a common phenomenon but is underrecognized by pathologists.

Gastric changes following colchicine therapy in patients with FMF

BACKGROUND

Familial Mediterranean fever (FMF) is also called recurrent polyserositis. The salient features of this disease include brief recurrent episodes of peritonitis, pleuritis, and arthritis, which are usually associated with fever. Colchicine is highly effective in the treatment of FMF and in preventing the development of recurrent attacks and amyloidosis, and it is essential to make the correct diagnosis and institute daily therapy with colchicine (0.5-0.6 mg bid). Colchicine is used to treat a variety of conditions but it is known to have gastrointestinal (GI) side effects. In this study, effects of colchicines on the gastrointestinal tract were evaluated in patients with FMF treated with colchicine.

METHODS

Biopsies were reviewed from 43 patients attending Ain Shams University Hospital (Egypt) who were diagnosed with FMF and treated with colchicine. One-hundred and twelve GI biopsies, obtained over a 14-year period, were reviewed. This included biopsies from stomach body (38), stomach antrum (50), and colon (24). In addition, gastric biopsies were reviewed from 17 control patients who did not have FMF and were not on colchicine.

RESULTS

Three patients known to have FMF and on colchicine therapy showed typical histological features of colchicine (metaphase mitoses, epithelial pseudoproliferation, mucin depletion, and frequent apoptosis). These features were seen only in gastric antral biopsies and not in colonic biopsies. None of the control group showed the characteristic morphological features of colchicine toxicity.

CONCLUSION

This is the first report of histological changes seen in the stomach following colchicine therapy. In contrast with previous reports, we did not find any definitive change in the large intestine. Our data show that gastric changes can be encountered in symptomatic patients who have recently had colchicine. If these finding are seen histologically, they merit correlation with the clinical impression and should not be interpreted as toxicity in isolation.

Apoptotic and inflammation markers in oral mucositis in head and neck cancer patients receiving radiotherapy: preliminary report

GOAL OF WORK

The aim of this study was to investigate the expression of pro-apoptotic protein p53 and anti-apoptotic proteins BCl-2 and MCl-1, as well as the expression of pro-inflammatory cytokines tumor necrosis factor (TNF) and interleukin-1beta (IL-1beta) in patients developing mucositis during radiotherapy for head and neck cancer.

MATERIALS AND METHODS

Thirty-five patients receiving radiotherapy for head/neck cancer were included in this study. Patients were examined before radiotherapy. Oral mucositis was recorded weekly during radiotherapy. Cytologic smears from the oral cavity were taken with a brush. Immunocytochemical staining was performed by the use of p53, BCl-2, MCl-1 TNF and IL-1beta monoclonal antibodies.

MAIN RESULTS

P53 was expressed in 1 of 15 smears before the initiation of radiotherapy (6.5%) compared to 3 of 7 smears from patients with grade III mucositis (43%) during radiotherapy. BCl-2 was expressed in 15 of 15 smears before radiotherapy (100%) and in three of seven patients with grade III mucositis (43%) during radiotherapy. MCl-1 was expressed in 10 of 14 samples before radiotherapy (71.5%) and in two of seven patients with grade III (28.5%) mucositis during radiotherapy. TNF was expressed in 9 of 14 patients before radiotherapy (64%) and in six of seven patients with grade III mucositis during radiotherapy (86%). IL-1beta was detected in 7 of 14 patients before radiotherapy (50%) compared to 6 of 7 patients with grade III mucositis during radiotherapy (86%).

CONCLUSION

Our preliminary results indicate an induction of apoptosis and inflammation in the oral mucosa in patients developing mucositis during radiotherapy for head/neck cancer.

Immunocytochemical studies on the distribution pattern of daunomycin in rat gastrointestinal tract

The cancer drug daunomycin is used in treatment of leukemia but possesses severe side effects that involve the gastrointestinal tract. We therefore used a newly developed immunocytochemical procedure to determine the distribution of DM in the gastrointestinal tracts of rats after i.v. injection. Two hours after injection, DM was diffusely distributed in nuclei and most parts of the cytoplasm of intestinal epithelial cells. The cytoplasmic immunoreactivity for DM was most pronounced in small granules of the apical cytoplasm. Sixteen hours after injection, DM immunostaining was by and large absent in the villous epithelium but persisted in the intestinal crypts. In addition, staining was also detected in endothelial cells, scattered cells of the lamina propria and in smooth muscle cells. After 5 days, only little staining for DM remained. Similar findings were made in the colon. In the gastric mucosa, DM accumulation persisted at 16 h in some glandular cells but was lost from the surface epithelium. No staining was detected in saline-injected control rats. The distribution of DM accumulation correlated partially with the distribution of apoptotic cells as detected by the TUNEL procedure. Our results pinpoint that DM may exert prolonged effects on glandular and regenerative cells of the gastrointestinal tract-an observation that may explain the gastrointestinal toxicity of the drug. It seems possible that DM accumulation in surface epithelial cells is rapidly cleared through drug transporters.

Protection against chemotherapy induced mucositis by TGF-beta(2) in childhood cancer patients: results from a randomized cross-over study

BACKGROUND

Mucositis is one of the most frequent and severe side-effect of chemotherapy in childhood-cancer patients for which there is no prophylaxis available. The efficacy and feasibility of a TGF-beta(2)-enriched feeding for preventing oral and gastro-intestinal-mucositis in childhood-cancer patients were studied.

PROCEDURE

The study was designed as a two-period cross-over, randomized, double-blinded, placebo, controlled trial. Patients who had a high risk for developing mucositis and who would receive two comparable cycles of chemotherapy were eligible for the study. During one cycle of chemotherapy, TGF-beta(2)-enriched feeding was administered; during the other, a "placebo" (not enriched) feeding was used. WHO toxicity scales of diarrhea, oral mucositis, fever, anal lesions and nausea/vomiting were scored daily. In addition, the incidence of occurrence of blood cultures, antibiotic therapy, and interventions or diagnostics related to mucositis were measured.

RESULTS

The feasibility of the study was good: 83% of the patients completed two cycles and 86% of the study-feeding was effectively consumed. Administration of TGF-beta(2) was safe as serum TGF-beta(2) did not increase, and renal and liver function were not affected during TGF-beta(2) consumption compared to normal feeding. Differences in toxicity, scored during the whole observation period and the number of days with WHO 3/4 toxicity, were not significantly different between cycles with TGF-beta(2) enriched and normal feeding.

CONCLUSIONS

TGF-beta(2) administration via feeding is well tolerated and safe. Although this study might have had limitations to show potential benefit of TGF-beta(2), it does not provide evidence that TGF-beta(2) decreases the incidence or degree of mucositis induced by combination chemotherapy in childhood-cancer patients.

Contributions of mucosal immune cells to methotrexate-induced mucositis

The use of high doses of the anti-cancer drug methotrexate (MTX) is associated with intestinal damage. As a result, mucosal immune cells become increasingly exposed to a vast amount of microbial stimuli. We aimed at determining whether these cells are still functional during MTX treatment. Furthermore, we assessed if activation of the mucosal immune system would play a role in the pathogenesis of mucositis. A contributive role to mucositis for the adaptive immune system was established by showing that mucosal lymphocytes from MTX-treated mice secreted enhanced amounts of cytokines upon ex vivo polyclonal stimulation. Next, in vitro experiments revealed that macrophages were not affected by MTX in the capacity to produce tumor necrosis factor-alpha (TNF-alpha) and IL-10 after LPS exposure. Moreover, peritoneal macrophages from MTX-treated mice produced more IL-10 and TNF-alpha upon LPS stimulation, compared with cells derived from control mice. These data indicate a persistence of both innate and adaptive immune responses in this model. The clinical relevance of these findings was further established by the fact that LPS exposure prior to MTX treatment aggravated the course of mucositis. Furthermore, LPS-responsive mice recovered more slowly compared with LPS-unresponsive mice from MTX treatment. Finally, we found an increase in weight loss and intestinal damage upon MTX treatment in IL-10-deficient mice in comparison to wild-type controls, suggesting a protective role for IL-10 in mucositis. We conclude that mucosal immune responses remain resilient during MTX-induced mucositis. Whereas TNF-alpha production may contribute to mucosal damage, IL-10 may regulate by restricting excessive mucositis.

Intestinal mucositis: the role of the Bcl-2 family, p53 and caspases in chemotherapy-induced damage

Intestinal mucositis occurs as a consequence of cytotoxic treatment through multiple mechanisms including induction of crypt cell death (apoptosis) and cytostasis. The molecular control of these actions throughout the gastrointestinal tract has yet to be fully elucidated; however, they are known to involve p53, the Bcl-2 family and caspases. This review will provide an overview of current research as well as identify areas where gaps in knowledge exist.

Cytotoxic chemotherapy upregulates pro-apoptotic Bax and Bak in the small intestine of rats and humans

AIMS

Small intestinal crypt cells rapidly undergo apoptosis in response to cytotoxic drug treatment that results in gastrointestinal toxicity. The Bcl-2 family have been implicated in both positive and negative regulation of intestinal cell apoptosis. The aim of this study was to examine the effect of cytotoxic treatment on Bcl-2 protein expression in patients and rats with tumours.

METHODS

Four pro- and four anti-apoptotic members of the Bcl-2 family, caspase-3 and p53 were examined in small intestinal crypts before and after treatment in rats and humans. Immunohistochemistry identified changes in protein expression over time, while relative RT-PCR was used to investigate mRNA expression in rat small intestine.

RESULTS

Cytotoxic treatment increased p53 and caspase-3 which coincided with elevated levels of apoptosis. Bax and Bak protein and mRNA expression also significantly increased at 6 hours following treatment in rats. Bax and Bak protein increased at day 1 after treatment in humans. Anti-apoptotic Mcl-1 protein decreased within 24hours. Other Bcl-2 family members showed only modest changes.

CONCLUSION

Increased expression of Bax and Bak but not other Bcl-2 family members is associated with apoptosis in small intestinal crypts and may amplify the sensitivity and susceptibility of crypt cells to chemotherapy-induced enteropathy.

Apoptosis in normal tissues induced by anti-cancer drugs

To investigate the damage mediated by anti-cancer drugs in normal cells, we examined the effect of such drugs on apoptosis of normal cells of the small intestinal epithelium and the bone marrow by in situ DNA end-labelling and transmission electron microscopy. Mice received a single dose of 5-fluorouracil (5-FU) or cisplatin, or repeated daily doses of 5-FU for 7 days. In mice treated with a single dose of 5-FU 50 mg/kg or cisplatin 5 mg/kg, the number of apoptotic cells appearing in the small intestine 12 h after injection was relatively small, but increased steadily reaching a peak after 36 h and then decreasing to close to that in the control group by 48 h. In bone marrow cells, results were similar in mice treated with single doses of 5-FU 50 mg/kg but apoptosis increased much less in those treated with cisplatin 5 mg/kg. The proportion of apoptotic cells reached peak values earlier at higher concentrations of 5-FU or cisplatin both in small intestine and in bone marrow. In the mice treated repeatedly with 5-FU 50 mg/kg, the proportion of apoptotic small intestinal epithelial cells reached a succession of peaks at 48-h intervals. Mice treated repeatedly with 5-FU 50 mg/kg also showed a rapid increase in diarrhoea symptoms and a steady decrease in the height of villi. Our results suggest it may be possible to prevent the side-effects of anti-cancer drugs by inhibiting apoptosis in the gastrointestinal tract.

Topical administration of a doxorubicin-specific monoclonal antibody prevents drug-induced mouth apoptosis in mice

One of the most severe side effects of anti-tumour chemotherapy is mucositis due to drug toxicity for rapidly dividing cells. We show here that anti-DXR monoclonal antibodies can prevent DXR-induced damage. Indeed, apoptosis, confined to the proliferative compartment of the basal mucosa, observed in the tongue of DXR-treated mice was completely inhibited by topical application of the anti-DXR antibodies.

Antitumour activity and adverse reactions of combined treatment with chitosan and doxorubicin in tumour-bearing mice

We examined the antitumour activity and adverse reactions, such as myelotoxicity, gastrointestinal toxicity and body-weight loss,of the cancer chemotherapy drug doxorubicin when given with chitosan in sarcoma 180-bearing mice. Intraperitoneally administered doxorubicin (5 mg kg(-1)) given on days 1 and 8 with or without orally administered chitosan (200, 400 and 800 mg kg(-1) twice daily) inhibited tumour growth. The orally administered chitosan (400 and 800 mg kg(-1) twice daily) prevented doxorubicin-induced body-weight loss and small-intestinal mucosal injury. Similarly, the reduction of leucocyte number induced by the intraperitoneally administered doxorubicin was restored to normal by the oral administration of chitosan (400 and 800 mg kg(-1) twice daily). It seems likely that the mechanisms by which the orally administered chitosan protects against doxorubicin-induced gastrointestinal toxicity may be due to the formation of doxorubicin-chitosan complex in the small-intestinal mucosa through the diffusion of chitosan into the small-intestinal villi. In conclusion, our data suggest that the oral administration of chitosan prevents the gastrointestinal mucositis associated with doxorubicin therapy.

Colchicine toxicity: distinct morphologic findings in gastrointestinal biopsies

Colchicine is an alkaloid with antimitotic ability used to treat a variety of medical conditions. Colchicine toxicity can result in multiorgan failure and death. The histopathologic features of colchicine toxicity in gastrointestinal biopsies have not been reported. Twenty-one gastrointestinal mucosal biopsies obtained from nine patients receiving oral colchicine therapy were studied. Immunohistochemical staining for Ki67 proliferation antigen was performed, and medical records of each patient were reviewed. All patients had a history of gout. Four patients with chronic renal failure also had clinical evidence of colchicine toxicity, and the other five patients did not. Distinct morphologic changes, seen as metaphase mitoses, epithelial pseudostratification, and loss of polarity, were seen in biopsy material from 4 of 4 (100%) patients with clinical colchicine toxicity. Three of these four cases (75%) also contained abundant crypt apoptotic bodies. These morphologic features were best seen in the biopsies from duodenum and gastric antrum, with relative sparing of the gastric body in the upper gastrointestinal tract. Ki67 staining demonstrated an expansion of the proliferating region in three available cases with clinical colchicine toxicity. These distinctive morphologic features were not seen in the five patients without clinical colchicine toxicity. These results indicate that colchicine toxicity can produce diagnostic morphologic features in gastrointestinal mucosal biopsies. Recognition of these features is important because colchicine toxicity can be fatal if undiagnosed clinically.

Comparison of enterotoxicity between autumn crocus (Colchicum autumnale L.) and colchicine in the guinea pig and mouse : enterotoxicity in the guinea pig differs from that in the mouse

Autumn crocus poisoning of cattle is characterized by severe diarrhea caused by alkaloid colchicine. Previously, we examined pathologically this poisoning in cattle and reported that enterotoxic lesions were closely associated with apoptosis. To examine enterotoxicity of autumn crocus more precisely, a reproductive study was performed using guinea pigs and mice, and pathological findings associated with autumn crocus poisoning were compared with those of colchicine. Each group of guinea pigs given the bulb of autumn crocus or colchicine exhibited severe diarrhea. Histopathological findings in intoxicated guinea pigs were entirely consistent with those in the autumn crocus-poisoned cattle. In contrast, each group of mice administered with the bulb or colchicine did not develop diarrhea. Our results confirmed that the toxicity of autumn crocus bulb is attributable to the toxicity of ingredient colchicine, and revealed that the guinea pig has high reproducibility of autumn crocus poisoning in cattle and colchicine poisoning in humans. It has been reported that the physiological mechanism of the apoptotic process for eliminating the enterocytes in the mouse and rat differs from that of the guinea pig, monkey, cattle and horse. Taking the observation that the former animals do not develop diarrhea, whereas the latter animals do so in the autumn crocus or colchicine poisoning into consideration, it would seem that the species-difference in enterotoxicity of autumn crocus may be closely associated with the physiological mechanism of eliminating the effete enterocytes.

Supplementary report on experimental autumn crocus (Colchicum autumnale L.) poisoning in cattle: morphological evidence of apoptosis

Previously we reported that tissue destruction characterized by the presence of karyopyknotic, karyorrhectic and mitotically arrested cells was seen in alimentary epithelial cells and lymphocytes in the lymphoid and hemopoietic systems of cattle experimentally administered with autumn crocus (Colchicum autumnale L.). This report deals with the mechanism of acute cellular injury following experimental autumn crocus poisoning in cattle as demonstrated by the in situ DNA strand break analysis and electron microscopy. The analyses revealed that cellular injury caused by autumn crocus was closely associated with apoptosis.

Identifying and quantifying apoptosis: a growth industry in the face of death

Apoptosis remains one of the hottest topics in cell biology, and great strides are being made in unravelling the complex interplay between the various regulatory molecules, particularly between the mammalian homologues of the nematode Caenorhabditis elegans death regulatory proteins Ced-3, Ced-4 and Ced-9. Curiously, the relative merits of the seemingly simple methodologies to visualize and quantify apoptosis still provoke considerable debate. Many are based on the ability to detect DNA breaks by enzyme-mediated addition of labelled nucleotides, but the capricious nature of many of the available labelling kits, combined with a lack of true specificity, continues to fuel the search for more reliable apoptosis 'markers'.

Applying computer modeling to examine complex dynamics and pattern formation of tissue growth

For research in areas such as developmental biology and cancer, understanding the formation and regrowth of tissue is of great importance. Since complex system behavior makes it difficult to interpret dynamics and pattern formation of tissue growth, it is helpful to have a way to simulate the cell systems and test hypotheses about the mechanisms by which the system is responding. Computer "modeling experiments" can serve this purpose, as we show with an example of the small intestine epithelial cells' response to cytosine arabinoside. This example demonstrates that nonhomogeneities in the cell population can play an important role and emphasizes the need to use a modeling approach, like our spatial modeling, that addresses the differences within the tissue structure. These types of "modeling experiments" can guide researchers with further experiments and provide clues as to how complex cell proliferation behavior is linked to underlying molecular phenomena.

N-(4-hydroxyphenyl)retinamide-induced death in human lymphoblastoid cells: 50 kb DNA breakage as a means of distinguishing apoptosis from necrosis

Experimental studies of N-(4-hydroxyphenyl)retinamide, a potential cancer chemopreventive agent, have primarily involved breast cancer and neuroblastoma cell populations together with an investigation of myeloid leukemia cells and have principally been concerned with the induction of apoptosis. This investigation of N-(4-hydroxyphenyl)retinamide-induced apoptosis using T-cell-derived human lymphoblastoid lines extends these studies by indicating distinctive features associated with this drug. The induction of apoptosis is restricted to a limited concentration range, which, if exceeded, results in cell death by necrosis. While morphological changes typical of apoptosis induced by many agents are readily demonstrable after treatment of lymphoblastoid cells with 3 microM N-(4-hydroxyphenyl)retinamide, distinctive features evident using the retinoid include the absence of cell cycle arrest along with the mode and pattern of DNA breakage. Analysis by conventional gel electrophoresis indicated that internucleosomal fragmentation of DNA was an unreliable indicator of apoptosis. On the other hand, higher order DNA breakage was consistently detected during drug-induced apoptosis, but not as a result of treatment causing necrosis.

Extracorporeal photochemotherapy induces apoptosis of infiltrating lymphoid cells in patients with mycosis fungoides in early stages. A quantitative histological study

Extracorporeal photochemotherapy (ExP) is a well-tolerated new form of chemoimmunotherapy, which is considered to be effective for cutaneous T-cell lymphoma (CTCL) and the treatment of choice for Sézary syndrome. Improvements have also been seen in patients with non-erythrodermic mycosis fungoides (MF) in the early stages, even when tumour cells are not detectable in the peripheral blood. In this study, we used ExP as a monotherapy in seven patients who had early stage (Ib) MF, and who were no longer responsive to or had contraindications for other therapies. We observed a clinical improvement in the disease after 12 months of treatment: one patient showed a complete response, five a partial response, and one remained stable. In each patient we compared skin biopsies of large plaque lesions before and after the treatment. We undertook a histological evaluation of the infiltrate. The lymphoid cell proliferation and death rates were quantified using the following parameters; lymphoid cell density (LCD), Ki67 + lymphoid cell nuclei percentage (Ki67 + Lcn percentage), and apoptotic index (AI). Significant decreases in the lymphoid cell infiltrate and in cell proliferation, and a significant increase in AI were observed after therapy. The mean LCD decreased from 187 +/- 33 to 34 +/- 17.7, Ki67 + Lcn mean percentage decreased from 16.9 +/- 3.9 to 4.9 +/- 2.4, and the AI mean value increased from 0.05 +/- 0.03 to 2.41 +/- 1.54. Our results suggest a role for apoptosis in the improvement of the skin lesions and are in line with some reports on the mode of action of ExP. Although the way in which ExP works needs to be clarified further, it does seem to stimulate a CD8+ cell-mediated anticlonotypic activity against circulating pathogenic clones. Furthermore, a release of tumour necrosis factor alpha (TNF-alpha) by circulating monocytes has been demonstrated after ExP. Both are known to induce cell death by apoptosis.

Effects of p53 mutations on apoptosis in mouse intestinal and human colonic adenomas

We have examined the effects of inactivation of the p53 tumor suppressor gene on the incidence of apoptotic cell death in two stages of the adenoma-to-carcinoma progression in the intestine: in early adenomas where p53 mutations are rare and in highly dysplastic adenomas where loss of p53 occurs frequently. Homozygosity for an inactivating germ-line mutation of p53 had no effect on the incidence or the rate of progression of ApcMin/+-induced adenomas in mice and also did not affect the frequency of apoptosis in the cells of these adenomas. To examine the effect of p53 loss on apoptosis in late-stage adenomas, we compared the incidence of apoptotic cell death before and after the appearance of highly dysplastic cells in human colonic adenomas. The appearance of highly dysplastic cells, which usually coincides during colon tumor progression with loss of heterozygosity at the p53 locus, did not correlate with a reduction in the incidence of apoptosis. These studies suggest that p53 is only one of the genes that determine the incidence of apoptotic in colon carcinomas and that wild-type p53 retards the progression of many benign colonic adenoma to malignant carcinomas by mechanism(s) other than the promotion of apoptosis.

Course of apoptotic changes in the rat gastric mucosa caused by oral administration of fusarenon-X

Male 5-week-old Wistar rats orally (po) administered with fusarenon-X (FX) 1.5 mg/kg and control rats po-treated with distilled water were sacrificed at 0-48 hr after gavage. FX-administered rats showed significant dilatation of the stomach with increased fluid contents at 1-24 hr postadministration (PA). Histopathologically, karyopyknosis of chief cells in the basal region of the gastric glands began to appear at 1 hr, and nuclear fragments were seen in the neck cell region at 1.5 hr PA. At 2-4 hr PA, apoptotic cells appeared diffusely in the neck region and focally in the basal region. Electron microscopy revealed that cells phagocytosing apoptotic bodies were the surface epithelia, undifferentiated neck cells, parietal cells and chief cells. No evidence was detected to show that parietal cells underwent apoptotic changes. The apoptotic lesions peaked at 4-6 hr PA, gradually subsided at 12 hr PA, and became minimal leaving apoptotic remnants in the basal region at 24 hr PA. At 48 hr PA, however, diffuse apoptotic lesions reappeared in the basal region at a level similar to that at 2-3 hr PA. This might be attributable to absorption of FX retaining in the stomach for 24 hr. In situ detection of DNA breaks by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction was consistent with the histopathologic findings. Agarose gel electrophoresis of DNA fragments isolated from the gastric mucosae of FX-administered rats showed a ladder pattern after 1.5 hr PA and the pattern became more distinct at 2-4 hr PA.

Intratibial injection of an anti-doxorubicin monoclonal antibody prevents drug-induced myelotoxicity in mice

With few exceptions, the major limit to high-dose chemotherapeutic treatments is the severity and duration of drug-induced myelosuppression. We have recently developed a monoclonal antibody, MAD11, which reacts with the potent anti-tumour antibiotic doxorubicin and other anthracyclines. To protect directly pluripotent stem cells and cells of the haematopoietic microenvironment in the bone marrow against doxorubicin cytotoxicity, the monoclonal antibody MAD11 was injected into the tibial bone of mice before chemotherapeutic treatment. All mice pretreated intratibially with MAD11 and injected with 14 mg kg(-1) body weight of doxorubicin survived, whereas 41% of mice treated with doxorubicin alone died. At a higher dose of doxorubicin (18 mg kg(-1)), early mortality (first 6 days) was similar in the groups, but no deaths were observed thereafter in the intratibially MAD11-treated group, whereas most of the mice treated with doxorubicin alone died. Data obtained in mice injected with P388 leukaemia cells showed that the intratibial injection of MAD11 did not compromise the anti-tumoral activity of doxorubicin. Moreover, the administration of the anti-doxorubicin monoclonal antibody before chemotherapeutic treatment effectively reduced apoptosis induced by doxorubicin in the bone marrow cells. These data suggest the usefulness of monoclonal antibodies against chemotherapeutic drugs in the local protection of bone marrow without influencing the anti-tumour properties of the drug.

Rapid apoptotic changes in the gastric glandular epithelium of rats administered intraperitoneally with fusarenon-X

Fusarenon-X (FX) 1.5 mg/kg was administered intraperitoneally (i.p.) to 6-week-old male Wistar rats for examination of pathologic effects on the glandular stomach. Rats ip-treated with sterilized physiological saline were used as control. FX-administered rats showed dilatation of the stomach with increased fluid contents after 1-4 hr. Light microscopically, a few apoptotic karyopyknosis were seen in chief cells in the basal region at 1 hr postadministration (PA) and mitotic inhibition was evident after 2 hr PA. Marked apoptosis of nuclear pyknosis and cytoplasmic inclusions in both zymogenic and oxyntic cells developed from basal to middle regions of the gastric mucous membrane at 2-4 hr PA with a peak at 3 hr. Apoptotic changes of differentiating neck cells and surface epithelia were less evident. Electron microscopy revealed that the chief cells were the main target of FX-induced apoptotosis. The parietal cells were secondarily involved because they phagocytosed chief cell-derived apoptotic bodies. In situ detection of DNA breaks by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction revealed the positive nuclei after 1 hr PA, which increased with time and reached a peak at 3 hr PA, in accordance with apoptotic changes in histological study. Agarose gel electrophoresis of DNA isolated from the gastric mucosae of FX-administered rats showed ladder pattern of DNA fragments after 1.5 hr PA with the maximum distinctness at 3 hr PA.

A rabbitpox virus serpin gene controls host range by inhibiting apoptosis in restrictive cells

Poxviruses are unique among viruses in encoding members of the serine proteinase inhibitor (serpin) superfamily. Orthopoxviruses contain three serpins, designated SPI-1, SPI-2, and SPI-3. SPI-1 encodes a 40-kDa protein that is required for the replication of rabbitpox virus (RPV) in PK-15 or A549 cells in culture (A. N. Ali, P. C. Turner, M. A. Brooks, and R. W. Moyer, Virology 202:305-314, 1994). Examination of nonpermissive human A549 cells infected with an RPV mutant disrupted in the SPI-1 gene (RPV delta SPI-1) suggests there are no gross defects in protein or DNA synthesis. The proteolytic processing of late viral structural proteins, a feature of orthopoxvirus infections associated with the maturation of virus particles, also appears relatively normal. However, very few mature virus particles of any kind are produced compared with the level found in infections with wild-type RPV. Morphological examination of RPV delta SPI-1-infected A549 cells, together with an observed fragmentation of cellular DNA, suggests that the host range defect is associated with the onset of apoptosis. Apoptosis is seen only in RPV delta SPI-1 infection of nonpermissive (A549 or PK-15) cells and is absent in all wild-type RPV infections and RPV delta SPI-2 mutant infections examined to date. Although the SPI-1 gene is expressed early, before DNA replication, the triggering apoptotic event occurs late in the infection, as RPV delta SPI-1-infected A549 cells do not undergo apoptosis when infections are carried out in the presence of cytosine arabinoside. While the SPI-2 (crmA) gene, when transfected into cells, has been shown to inhibit apoptosis, our experiments provide the first indication that a poxvirus serpin protein can inhibit apoptosis during a poxvirus infection.

Ceramide synthase mediates daunorubicin-induced apoptosis: an alternative mechanism for generating death signals

The sphingomyelin pathway, which is initiated by sphingomyelin hydrolysis to generate the second messenger ceramide, signals apoptosis for tumor necrosis factor alpha, Fas, and ionizing radiation. In the present studies, the anticancer drug daunorubicin also stimulated ceramide elevation and apoptosis in P388 and U937 cells. Cell-permeable analogs of ceramide, but not other lipid second messengers, mimicked daunorubicin in inducing apoptosis. Daunorubicin-stimulated ceramide elevation, however, did not result from sphingomyelin hydrolysis, but rather from de novo synthesis via activation of the enzyme ceramide synthase. An obligatory role for ceramide synthase was defined, since its natural specific inhibitor, fumonisin B1, blocked daunorubicin-induced ceramide elevation and apoptosis. These studies demonstrate that ceramide synthase activity can be regulated in eukaryotes and constitute definitive evidence for a requirement for ceramide elevation in the induction of apoptosis.

Two modes of hair cell loss from the vestibular sensory epithelia of the guinea pig inner ear

In the vestibular and auditory neurosensory epithelia of poikilothermic vertebrates and of birds, damaged sensory "hair" cells are often deleted by extrusion from the apical surface. In contrast, in the adult mammalian auditory epithelium (the organ of Corti), the bodies of damaged hair cells degenerate within the epithelium. To determine whether this apparent difference is species related or is associated with the differing structural organisation of the epithelia, hair cell deletion in the mammalian vestibular end-organs was examined. The structural organisation of these tissues is closer to that of the inner ear epithelia of lower vertebrates than to the organ of Corti. Hair cell loss was induced by chronic, systemic treatment of guinea pigs with the ototoxic aminoglycoside antibiotic gentamicin. The vestibular sensory epithelia were examined at various times after treatment via scanning electron microscopy, thin sectioning, and staining f-actin with fluorescently labelled phalloidin. Two distinct modes of hair cell loss were identified: 1) degeneration of hair cells within the epithelium, which often showed morphological features consistent with those described for apoptosis, and 2) extrusion of intact cells from the apical surface. Neither process caused the formation of obvious lesions through the epithelial surfaces. Expansion of adjacent supporting cells during hair cell deletion resulted in repair that appeared to preserve permeability barriers. There was also no evidence of inflammation accompanying hair cell removal. Thus, with both modes of hair cell loss, it appeared that deletion of hair cells was achieved without disruption of tissue architecture or integrity. This may be important for subsequent repair and regeneration processes to operate.

Role of apoptosis in modulation of the growth of human colorectal tubular and villous adenomas

To estimate the effect of cell proliferation and deletion on the growth of the human colorectal adenoma, 27 tubular adenomas and eight villous adenomas were examined. Tubular adenomas were categorized into three grades of cellular atypia: mild, moderate, and severe. Villous adenomas were given a single grade. Morphological characteristics of apoptosis (nuclear condensation and budding) were used to quantify an apoptotic index, AI (percentage of apoptotic cells in viable adenomatous cells). The apoptotic cells were found mainly among the basal site of the adenomatous tubules. The AIs of tubular adenomas with mild, moderate, and severe grades of atypia were 3.5, 5.7 and 8.8 per cent, respectively. The AI of villous adenomas was 1.8 per cent, which was significantly lower than that of tubular adenomas. The mitotic indices, MIs (percentage of mitotic cells in viable adenomatous cells) of tubular adenomas were 0.41 per cent (mild), 0.58 per cent (moderate), and 0.83 per cent (severe), and for villous adenomas the MI was 0.38 per cent. There was a close positive relationship between the AI and MI of tubular adenomas, which paralleled the grade of atypia. These results indicate that both cell proliferation and death were more frequent in adenomas with severe atypia than in adenomas with mild atypia. Moreover, the significantly lower AI of villous adenomas, known to develop into large tumours when compared with tubular adenomas, suggests that reduced apoptoses may lead to a shift in tissue kinetics towards expansive growth.

Apoptosis: regulation and relevance to toxicology

1. Apoptosis is a remarkably stereotyped morphological event across all tissues in response to a vast array of damaging agents. 2. Our very existence depends upon a willing exchange of old life for new: apoptotic cell death is our guardian and saviour from genetic damage. 3. There is a close link between cell proliferation and apoptosis: When a cell picks up the machinery to proliferate it also acquires an abort pathway--'better dead than wrong'. 4. A wide variety of highly conserved genes have been implicated in triggering apoptosis. 5. The release of DNA loops from the nuclear scaffold is a more crucial intracellular event than DNA 'laddering' in apoptotic cells. 6. The manipulation of apoptotic rates in many of the common diseases in man will be a major therapeutic strategy in the future.

Recombinant transforming growth factor beta 1 and beta 2 protect mice from acutely lethal doses of 5-fluorouracil and doxorubicin

Transforming growth factor beta 1 (TGF-beta 1) and TGF-beta 2 can reversibly inhibit the proliferation of hematopoietic progenitor cells in vivo, leading us to hypothesize that such quiescent progenitors might be more resistant to high doses of cell cycle active chemotherapeutic drugs, thereby allowing dose intensification of such agents. Initial studies showed that whereas administration of TGF-beta 1 or TGF-beta 2 did not prevent death in normal mice treated with high doses of 5-fluorouracil (5-FU), those mice that received TGF-beta 2 did exhibit the beginning of a hematologic recovery by day 11 after administration of 5-FU, and were preferentially rescued by a suboptimal number of transplanted bone marrow cells. Subsequently, it was found that the administration of TGF-beta 2 protected recovering progenitor cells from high concentrations of 5-FU in vitro. This protection coincided with the finding that significantly more progenitors for colony-forming unit-culture (CFU-c) and CFU-granulocyte, erythroid, megakaryocyte, macrophage (GEMM) were removed from S-phase by TGF-beta in mice undergoing hematopoietic recovery than in normal mice. Further studies showed that the administration of TGF-beta protected up to 90% of these mice undergoing hematologic recovery from a rechallenge in vivo with high dose 5-FU, while survival in mice not given TGF-beta was < 40%. Pretreatment of mice with TGF-beta 1 or TGF-beta 2 also protected 70-80% of mice from lethal doses of the noncycle active chemotherapeutic drug, doxorubicin hydrochloride (DXR). These results demonstrate that TGF-beta can protect mice from both the lethal hematopoietic toxicity of 5-FU, as well as the nonhematopoietic toxicity of DXR. This report thus shows that a negative regulator of hematopoiesis can be successfully used systemically to mediate chemoprotection in vivo.

The morphological effects of the anti-tumor agents flavone acetic acid and 5,6-dimethyl xanthenone acetic acid on the colon 38 mouse tumor

Flavone acetic acid and 5,6-dimethyl xanthenone acetic acid have a broad spectrum of anti-tumor activity in mice, and act by stimulating immune cells and inhibiting tumor blood flow, resulting in hemorrhagic necrosis within 24 hrs. To study the evolution of hemorrhagic necrosis, subcutaneous Colon 38 tumors were examined by light and electron microscopy from 30 min to 24 hrs after treatment with these agents, and measurements of tumor energy metabolites made. The results show that both agents cause apoptosis beginning at 30 min, and that by 4 hrs necrosis supervenes, accompanied by rupture of tumor blood vessels. The absence of early endothelial cell damage or thrombosis suggests that vessel rupture, and consequent loss of blood flow and energy metabolite depletion, is caused by loss of extravascular mechanical support by the tumor parenchyma.