The haemotoxicity of mitomycin in a repeat dose study in the female CD-1 mouse

Treating colorectal peritoneal metastases with an injectable cytostatic loaded supramolecular hydrogel in a rodent animal model

Patients with peritoneal metastases (PM) of colorectal cancer have a very poor outcome. Intraperitoneal delivery of chemotherapy is the preferred route for PM treatment. The main limitation of the treatment options is the short residence time of the cytostatic, with subsequent short exposure of the cancer cells. To address this, a supramolecular hydrogel has been developed that allows both local and slow release of its encapsulated drug, mitomycin C (MMC) or cholesterol-conjugated MMC (cMMC), respectively. This experimental study investigates if drug delivery using this hydrogel improves the therapeutic efficacy against PM. PM was induced in WAG/Rij rats (n = 72) by intraperitoneally injecting syngeneic colon carcinoma cells (CC531) expressing luciferase. After seven days, animals received a single intraperitoneal injection with saline (n = 8), unloaded hydrogel (n = 12), free MMC (n = 13), free cMMC (n = 13), MMC-loaded hydrogel (n = 13), or cMMC-loaded hydrogel (n = 13). Primary outcome was overall survival with a maximum follow-up of 120 days. Intraperitoneal tumor development was non-invasive monitored via bioluminescence imaging. Sixty-one rats successfully underwent all study procedures and were included to assess therapeutic efficacy. After 120 days, the overall survival in the MMC-loaded hydrogel and free MMC group was 78% and 38%, respectively. A trend toward significance was found when comparing the survival curves of the MMC-loaded hydrogel and free MMC (p = 0.087). No survival benefit was found for the cMMC-loaded hydrogel compared to free cMMC. Treating PM with our MMC-loaded hydrogel, exhibiting prolonged MMC exposure, seems effective in improving survival compared to treatment with free MMC.

Use of Self-Assembled Colloidal Prodrug Nanoparticles for Controlled Drug Delivery of Anticancer, Antifibrotic and Antibacterial Mitomycin

Herein we present the synthesis of a polymeric prodrug nanomaterial capable of spontaneous, self-assembled nanoparticle formation and of the conjugation (encapsulation) of drugs with amino and/or carboxyl and/or hydroxyl groups via ester and/or amide linkage. Mitomycin C (MMC) a versatile drug with antibiotic, antibacterial and antineoplastic properties, was used to prove this concept. The in vitro drug release experiments showed a fast release for the pure MMC (k = 49.59 h^-n); however, a significantly lower MMC dissolution rate (k = 2.25, 1.46, and 1.35 h^-n) was obtained for the nanoparticles with increased cross-link density (3, 10, 21%). The successful modification and conjugation reactions were confirmed using FTIR and EDX measurements, while the mucoadhesive properties of the self-assembled particles synthesized in a simple one-pot reaction were proved by rheological measurement. The prepared biocompatible polymeric prodrugs are very promising and applicable as a drug delivery system (DDS) and useful in the area of cancer treatment.

Efficacy of the new therapeutic approach in curing malignant neoplasms on the model of human glioblastoma

OBJECTIVE

Glioma is a highly invasive tumor, frequently disposed in essential areas of the brain, which makes its surgical excision extremely difficult; meanwhile adjuvant therapy remains quite ineffective.

METHODS

In the current report, a new therapeutic approach in curing malignant neoplasms has been performed on the U87 human glioblastoma model. This approach, termed "Karanahan", is aimed at the eradication of cancer stem cells (CSCs), which were recently shown to be capable of internalizing fragments of extracellular double-stranded DNA. After being internalized, these fragments interfere in the process of repairing interstrand cross-links caused by exposure to appropriate cytostatics, and such an interference results either in elimination of CSCs or in the loss of their tumorigenic potency. Implementation of the approach requires a scheduled administration of cytostatic and complex composite double-stranded DNA preparation.

RESULTS

U87 cells treated in vitro in accordance with the Karanahan approach completely lost their tumorigenicity and produced no grafts upon intracerebral transplantation into immunodeficient mice. In SCID mice with developed subcutaneous grafts, the treatment resulted in reliable slowing down of tumor growth rate (P < 0.05). In the experiment with intracerebral transplantation of U87 cells followed by surgical excision of the developed graft and subsequent therapeutic treatment, the Karanahan approach was shown to reliably slow down the tumor growth rate and increase the median survival of the mice twofold relative to the control.

CONCLUSIONS

The effectiveness of the Karanahan approach has been demonstrated both in vitro and in vivo in treating developed subcutaneous grafts as well as orthotopic grafts after surgical excision of the tumor.

Occupational exposure to cytostatic fumes during hyperthermic intraperitoneal chemotherapy

Hyperthermic intraperitoneal chemotherapy (HIPEC)-heated, intra-abdominal chemotherapy-has become the treatment of choice for treating peritoneal metastases from ovarian, stomach or colorectal cancers. HIPEC has several advantages and disadvantages. The major benefit is minimal systemic toxicity for the patient, but there is a risk of occupational exposure for operating room staff. We have not found any reports of workers with chronic aplastic anaemia as a result of exposure to cytostatic fumes during HIPEC. The aim of this case report is to raise the awareness of potential negative health effects of inhalation exposure to cytostatic drugs. We present a rare case of a 43-year-old woman, suffering from aplastic anaemia as a long-term consequence of exposure to cytostatics. During the HIPEC procedure, surgical revision of the peritoneal cavity was undertaken which resulted in release of cytostatic fumes. Despite awareness of the health effects of occupational exposure to cytostatic drugs and well-developed procedures for safely handling them, unexpected exposure may occur causing serious medical conditions. These may develop in sensitive subjects although accidental high-level exposure may lead to unexpected long-term consequences in all workers. Medical staff need to be informed of the risks of HIPEC and safety guidelines to reduce the risk of exposure.

Loss of PBRM1 rescues VHL dependent replication stress to promote renal carcinogenesis

Inactivation of the VHL (Von Hippel Lindau) tumour suppressor has long been recognised as necessary for the pathogenesis of clear cell renal cancer (ccRCC); however, the molecular mechanisms underlying transformation and the requirement for additional genetic hits remain unclear. Here, we show that loss of VHL alone results in DNA replication stress and damage accumulation, effects that constrain cellular growth and transformation. By contrast, concomitant loss of the chromatin remodelling factor PBRM1 (mutated in 40% of ccRCC) rescues VHL-induced replication stress, maintaining cellular fitness and allowing proliferation. In line with these data we demonstrate that combined deletion of Vhl and Pbrm1 in the mouse kidney is sufficient for the development of fully-penetrant, multifocal carcinomas, closely mimicking human ccRCC. Our results illustrate how VHL and PBRM1 co-operate to drive renal transformation and uncover replication stress as an underlying vulnerability of all VHL mutated renal cancers that could be therapeutically exploited.

Polyuria-associated hydronephrosis induced by xenobiotic chemical exposure in mice

Hydronephrosis is a commonly found disease state characterized by the dilation of renal calices and pelvis, resulting in the loss of kidney function in the severest cases. A generally accepted etiology of hydronephrosis involves the obstruction of urine flow along the urinary tract. In the recent years, we have developed a mouse model of hydronephrosis induced by lactational exposure to dioxin and demonstrated a lack of anatomical obstruction in this model. We also showed that prostaglandin E2 synthesis system plays a critical role in the onset of hydronephrosis. In the present study, we found that neonatal hydronephrosis was not likely to be associated with functional obstruction (impaired peristalsis) but was found to be associated with polyuria and low urine osmolality with the downregulation of proteins involved in the urine concentrating process. The administration of an antidiuretic hormone analog to the dioxin-exposed pups not only suppressed the increased urine output but also decreased the incidence and severity of hydronephrosis. In contrast to the case in pups, administration of dioxin to adult mice failed to induce polyuria and upregulation of prostaglandin E2 synthesis system, and the adult mice were resistant to develop hydronephrosis. These findings suggest the possibility that polyuria could induce hydronephrosis in the absence of anatomical or functional obstruction of the ureter. It is concluded that the present animal model provides a unique example of polyuria-associated type of hydronephrosis, suggesting a need to redefine this disease state.

Mitigating effect of Indian propolis against mitomycin C induced bone marrow toxicity

A major drawback with cancer chemotherapy is its severe toxic effects on non-target tissues. Assessment of natural products for their protective effect against anticancer drugs-induced toxicity is gaining importance in cancer biology. The present study was aimed at assessing the protective effect of hydroethanolic extract of Indian propolis (HEIP) against mitomycin C (MMC)-induced genotoxicity and cytotoxicity. Swiss albino mice were injected with various doses of HEIP (100, 200, 300, 400, 600 and 800 mg/kg b. wt., i.p) 1 h prior to MMC (8 mg/kg, i.p.) injection. The geno- and cyto-toxicities were evaluated in mice by performing bone marrow micronucleus and TUNEL assays. In vitro antioxidant and lipid peroxidation inhibitory assays were carried out to understand the mechanism of the protective effects. The significant increase in the frequency of micronculeated cells (12.51 ± 0.48), apoptotic cells (23.43 ± 1.86) and reduction in P/N ratio (0.69 ± 0.04) compared with control indicated the potential geno- and cytotoxic effects of MMC in bone marrow. Pretreatment with HEIP resulted in the significant recovery of the toxic effects induced by MMC. HEIP at 400 mg/kg b. wt. was found to be the optimum dose imparting the maximum protective effects. The in vitro antioxidant and lipid peroxidation inhibitory assays suggest that the extract possesses substantial free radical scavenging activities. In conclusion, HEIP possesses substantial geno- and cyto-protective properties against MMC, which could be mediated through efficient free radical scavenging and inhibitory effect on lipid peroxidation.

Predominant role of cytosolic phospholipase A2α in dioxin-induced neonatal hydronephrosis in mice

Hydronephrosis is a common disease characterized by dilation of the renal pelvis and calices, resulting in loss of kidney function in the most severe cases. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces nonobstructive hydronephrosis in mouse neonates through upregulation of prostaglandin E₂ (PGE₂) synthesis pathway consisting of cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) by a yet unknown mechanism. We here studied possible involvement of cytosolic phospholipase A₂α (cPLA₂α) in this mechanism. To this end, we used a cPLA₂α-null mouse model and found that cPLA₂α has a significant role in the upregulation of the PGE₂ synthesis pathway through a noncanonical pathway of aryl hydrocarbon receptor. This study is the first to demonstrate the predominant role of cPLA₂α in hydronephrosis. Elucidation of the pathway leading to the onset of hydronephrosis using the TCDD-exposed mouse model will deepen our understanding of the molecular basis of nonobstructive hydronephrosis in humans.

Pathogenesis of emerging severe fever with thrombocytopenia syndrome virus in C57/BL6 mouse model

The discovery of an emerging viral disease, severe fever with thrombocytopenia syndrome (SFTS), caused by SFTS virus (SFTSV), has prompted the need to understand pathogenesis of SFTSV. We are unique in establishing an infectious model of SFTS in C57/BL6 mice, resulting in hallmark symptoms of thrombocytopenia and leukocytopenia. Viral RNA and histopathological changes were identified in the spleen, liver, and kidney. However, viral replication was only found in the spleen, which suggested the spleen to be the principle target organ of SFTSV. Moreover, the number of macrophages and platelets were largely increased in the spleen, and SFTSV colocalized with platelets in cytoplasm of macrophages in the red pulp of the spleen. In vitro cellular assays further revealed that SFTSV adhered to mouse platelets and facilitated the phagocytosis of platelets by mouse primary macrophages, which in combination with in vivo findings, suggests that SFTSV-induced thrombocytopenia is caused by clearance of circulating virus-bound platelets by splenic macrophages. Thus, this study has elucidated the pathogenic mechanisms of thrombocytopenia in a mouse model resembling human SFTS disease.

Lymphopenia in patients with chronic idiopathic neutropenia is associated with decreased number of T-lymphocytes containing T-cell receptor excision circles

OBJECTIVES

Chronic idiopathic neutropenia (CIN) is a disorder of granulopoiesis characterized by the presence of activated T-lymphocytes that induce/sustain apoptosis of bone marrow (BM) granulocytic progenitors. T-cell lymphopenia is commonly found in CIN. The aim of the study is to probe the mechanisms underlying T-cell lymphopenia in CIN.

METHODS

We investigated parameters of T-cell homeostasis namely the proliferation/apoptotic rate of naïve and memory T cells, the T-cell senescence by telomere measurement, the recent thymic T-cell production through quantification of T-cell receptor rearrangement excision circles (TRECs), and the production of interleukin (IL)-7.

RESULTS

Patients with CIN (n = 44) displayed lower proportion of naïve CD45RA(+) cells within the CD4(+) and CD8(+) cells compared with controls (n = 15). The proportion of apoptotic cells within the CD8(+) fraction was higher in patients compared with controls and was correlated with the percentage of Ki-67(+) cells, indicating an activation-induced accelerated CD8(+) cell death. The TREC content of CD4(+) and CD8(+) cells was lower in patients compared with controls and was correlated with the proportion of CD45RA(+) CD4(+) and CD8(+) cells and with the levels of serum and BM IL-7, which were significantly decreased in the patients. The mean relative telomere length of CD4(+) and CD8(+) cells was significantly lower in patients with CIN compared with age-matched controls.

CONCLUSIONS

The aberrant T-cell expansions associated with the pathogenesis of CIN result in increased proliferation/apoptosis and possibly exhaustion of peripheral blood T cells which, in association with the inadequate compensatory thymic export of new TREC expressing T cells partially because of IL-7 deficiency, may contribute to lymphopenia in CIN.

Evaluation of differential representative values between Chinese hamster cells and human lymphocytes in mitomycin C-induced cytogenetic assays and caspase-3 activity

Chinese hamster ovary (CHO) cells, its lung fibroblasts (V79), and human lymphocytes are routinely used in in vitro cytogenetic assays, which include micronuclei (MN), sister chromatid exchange (SCE), and chromosome aberration (CA) assays. Mitomycin C (MMC), a DNA cross-link alkylating agent, is both an anticancer medicine and a carcinogen. To study the differential representative values of cell types in MMC-treated cytogenetic assays and its upstream factor, cysteine aspartic acid-specific protease (caspase)-3. Among the chosen cell types, lymphocytes expressed the highest sensitivity in all three MMC-induced assays, whereas CHO and V79 showed varied sensitivity in different assays. In MN assay, the sensitivity of CHO is higher than or equal to V79; in SCE assay, the sensitivity of CHO is the same as V79; and in CA assay, the sensitivity of CHO is higher than V79. In-depth analysis of CA revealed that in chromatid breaks and dicentrics formation, lymphocyte was the most sensitive of all and CHO was more sensitive than V79; and in acentrics and interchanges formation, lymphocyte was much more sensitive than the others. Furthermore, we found caspase-3 activity plays an important role in MMC-induced cytogenetic assays, with MMC-induced caspase-3 activity resulting in more sensitivity in lymphocytes than in CHO and V79. Based on these findings, lymphocyte will make a suitable predictive or representative control reference in cytogenetic assays and caspase-3 activity with its high specificity, positive predictive value, and sensitivity.

Haemotoxicity of busulphan, doxorubicin, cisplatin and cyclophosphamide in the female BALB/c mouse using a brief regimen of drug administration

Many anticancer drugs are myelotoxic and cause bone marrow depression; however, generally, the marrow/blood returns to normal after treatment. Nevertheless, after the administration of some anti-neoplastic agents (e.g. busulphan, BU) under conditions as yet undefined, the marrow may begin a return towards normal, but normality may not be achieved, and late-stage/residual marrow injury may be evident. The present studies were conducted to develop a short-term mouse model (a 'screen') to identify late-stage/residual marrow injury using a brief regimen of drug administration. Female BALB/c mice were treated with BU, doxorubicin (DOX), cisplatin (CISPLAT) or cyclophosphamide (CYCLOPHOS) on days 1, 3 and 5. In 'preliminary studies', a maximum tolerated dose (MTD) for each drug was determined for use in 'main studies'. In main studies, mice were treated with vehicle (control), low and high (the MTD) dose levels of each agent. Necropsies were performed, and blood parameters and femoral/humeral nucleated marrow cell counts (FNCC/HNCC) were assessed on six occasions (from days 1 to 60/61 post-dosing). Late-stage/residual changes were apparent in BU-treated mice at day 61 post-dosing: RBC, Hb and haematocrit were reduced, mean cell volume/mean cell haemoglobin were increased and platelet and FNCC counts were decreased. Mice given DOX, CISPLAT and CYCLOPHOS, in general, showed no clear late-stage/residual effects (day 60/61). It was concluded that a brief regimen of drug administration, at an MTD, with assessment at day 60/61 post-dosing was a suitable short-term method/screen in the mouse for detecting late-stage/residual marrow injury for BU, a drug shown to exhibit these effects in man.

Engraftment of syngeneic and allogeneic endothelial cells, hepatocytes and cholangiocytes into partially hepatectomized rats previously treated with mitomycin C

BACKGROUND

Pretreatment with retrorsine crosslinks host hepatocyte DNA and prevents proliferation after partial hepatectomy (PH), allowing selective expansion of transplanted progenitors. Shortcomings are length of protocol and carcinogenicity of retrorsine.

METHODS

This report describes a rapid liver repopulation protocol using mitomycin C (MMC) to block proliferation of rat hepatocytes in response to PH. One week post-MMC treatment, dipeptidyl peptidase IV negative host rats were given a PH followed by injection of late gestation, newborn, or adult total liver isolates from dipeptidyl peptidase IV positive rats. For allogeneic transplantation, host rats received injections of anti-CD3 antibody before and after PH.

RESULTS

Host liver staining 2 to 9 weeks posttransplantation revealed well-defined donor hepatocyte colonies with strong canalicular dipeptidyl peptidase IV activity. At the same cell dose, fetal and newborn isolates produced more colonies than adult liver isolates. Hepatocyte colonies also coexpressed marker proteins characteristic of adult hepatocytes and showed polarized localization of plasma membrane proteins. Host livers contained large clusters of sinusoids lined by dipeptidyl peptidase IV positive endothelial cells coexpressing the endothelial cell marker, RECA-1, but lacked the canalicular marker leucine aminopeptidase. Colonies containing donor hepatocytes, endothelial cells, and bile ducts were also observed. Similar levels of engraftment and expansion were achieved with allogeneic liver cell isolates by using anti-CD3 antibody treatment.

CONCLUSIONS

The MMC transplantation model provides a rapid method for engraftment and expansion of hepatocytes, endothelial cells, and cholangiocytes and should be applicable to investigations centering on the role of endothelial cells in liver regeneration and the identification and characterization of putative endothelial, hepatocyte, and cholangiocyte progenitors.

Near-optimal conditions for the in vitro culture of hemopoietic progenitor cells in bone marrow from the rat

In vitro techniques for the culture of hemopoietic stem cells and committed hemopoietic progenitor cells in rat bone marrow have not been adequately described in the literature. In the present investigations, and using commercially available hemopoietic cytokines and growth factors, the conditions required to perform long-term bone marrow culture (LTBMC) using rat femoral bone marrow were studied, in conjunction with the colony-forming unit cell assay (CFU-C), to quantify the number of progenitor cells. CFU-C production by LTBMCs, set up using Iscove's modified Dulbecco's medium supplemented with fetal calf serum and horse serum, ceased after week 2 of culture. However, the duration of CFU-C production was significantly increased by supplementing LTBMCs with the cytokine recombinant mouse stem cell factor or recombinant rat stem cell factor.

Renal damage and death in weaned mice after oral infection with Shiga toxin 2-producing Escherichia coli strains

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infections are considered a public health problem in both developed and developing countries because of their increasing incidence and the severity of clinical presentation. Approximately 10% of infected patients develop complications such as haemolytic uraemic syndrome (HUS) characterized by acute renal failure, thrombocytopenia and haemolytic anaemia. The precise sequence of events leading to HUS is still understood incompletely. Because of the lack of a reproducible small animal model for EHEC infections, in vivo studies examining EHEC-host early interactions are limited and insufficient. The aim of this study was to characterize the weaned BALB/c mouse as a model of E. coli O157:H7 infection. In this paper we report that human Shiga toxin 2 (Stx2)-producing EHEC strains can adhere to the intestinal epithelium of weaned BALB/c mice, and produce local damage which leads to systemic disease and death in a percentage of infected mice. The lethality of the EHEC strain is closely age-dependent, and is related to the bacterial ability to colonize intestine and to produce Stx2. It can be concluded that the weaned BALB/c mouse can be used as a small animal model to study host early responses, and the role of bacterial pathogenic factors in the induction of systemic disease, thus providing a useful tool for the evaluation of therapeutic or vaccine approaches.

Serum FLT-3 ligand in a busulphan-induced model of chronic bone marrow hypoplasia in the female CD-1 mouse

The concentration of the cytokine fms-like tyrosine kinase-3 ligand (FL) is elevated in the plasma of patients treated with chemotherapy or radiotherapy for malignant conditions. In addition, plasma FL is increased in patients with bone marrow failure resulting from stem-cell defects (e.g. aplastic anaemia). Our goal in the present study was to measure the concentration of serum FL in mice treated with the chemotherapeutic agent busulphan (BU) to induce bone marrow depression and relate changes in FL to effects on haemopoiesis. Female CD-1 mice were treated with BU (9.0 mg/kg) or vehicle by intraperitoneal injection on 10 occasions over 21 days. Animals were autopsied on days 1, 23, 72, 119 and 177 postdosing. A full blood count was performed, and serum prepared for FL analysis. Femoral marrow cell suspensions were prepared to assess the total femoral nucleated cell count (FNCC) and the number of committed haemopoietic progenitor cells (CFU-C). On days 1 and 23 postdosing, significant decreases were evident in many peripheral blood parameters; the FNCC and CFU-C were also reduced in BU-treated mice, in conjunction with increases in serum FL levels. On days 72, 119 and 177 postdosing, several peripheral blood and bone marrow parameters remained reduced and the concentration of serum FL continued to be significantly increased. Linear regression analysis demonstrated significant correlations between the concentration of serum FL in BU-treated mice and peripheral blood and bone marrow parameters; this suggests the possible use of serum FL as a potential biomarker for drug-induced bone marrow injury.

Protective effects of American ginseng (Panax quinquefolium) against mitomycin C induced micronuclei in mice

Mitomycin C (MMC) is a highly active anticancer drug commonly used alone and in combination with other chemotherapeutic agents for the treatment of different cancers. Its bioactivated form critically damages the DNA present in both rapidly dividing cancerous cells as well as in normal cells. Genotoxicity in the normal cells makes this drug highly toxic; thereby decreasing its therapeutic index for clinical use. The study investigated the chemoprotective potential of American ginseng root extract against MMC by using the micronuclei test in a mouse test system. Pre-treatment with ginseng at doses 50 mg/kg and 100 mg/kg, p.o. for 3 and 7 days significantly decreased the frequency of micronucleated polychromatic erythrocytes (PCEs). Similar protective effects were also observed during co-treatment with ginseng at similar doses for 3 and 7 days. The present results indicate that American ginseng extract is capable of suppressing the chromosomal aberration induced by MMC in mice. Thus, American ginseng may be a potent chemoprotective agent against the toxicity of the anticancer drug, mitomycin C.

The haemotoxicity of azathioprine in repeat dose studies in the female CD-1 mouse

Azathioprine (AZA) is a cytotoxic immunosuppressive drug used in the prevention of rejection in organ transplants and the treatment of auto-immune diseases. However, AZA is haemotoxic causing significant bone marrow depression. The present studies were to characterize the haemotoxicity of AZA in the female CD-1 mouse. In Experiment 1, a dose-ranging study, with AZA gavaged daily for 10 days, clinical evidence of toxicity was evident at 125 mg/kg and above. Experiment 2 was a dose-response study with AZA gavaged daily for 10 days at 40-120 mg/kg. At day 1 after the final dose, AZA induced a dose-related pancytopaenia, reduced femoral marrow cellularity, increases in serum levels of the cytokine fms-like tyrosine kinase 3 ligand, reduction in granulocyte-monocyte colony-forming units and erythroid colonies, and increased bone marrow apoptosis. Histology demonstrated hepatocyte hypertrophy, thymic atrophy, reduced splenic extramedullary haemopoiesis, and reduced cellularity of sternal bone marrow. In Experiment 3, AZA was dosed for 10 days at 100 mg/kg with autopsies at 1, 3, 9, 22, 29, 43 and 57 days postdosing. At 1, 3 and 9 days, haematological parameters reflected changes in Experiment 2. At 22/29 days, many blood parameters were returning towards normal; at 43/57 days, most parameters compared with controls. However, there was some evidence of a persistent (i.e. residual/late-stage) mild reduction in RBC and erythroid progenitor cell counts at day 43/57. We conclude that the CD-1 mouse provides an acceptable model for the haemotoxicity of AZA in man.

Inhibition of tumor implantation after laparoscopy by specific oligopeptides: a novel approach to adjuvant intraperitoneal therapy to prevent tumor implantation in an animal model

OBJECTIVES

The development of intra-abdominal tumor spread and port-site metastases in urothelial cancer are still questions regarding the safety of laparoscopic methods for the resection of malignancies. Currently, the actual incidence of intra-abdominal tumor spread and port-site metastasis remains unknown. Herein, we investigated the influence of antiadhesive oligopeptides and cytotoxic agents (administered intraperitoneally) on implantation of a tumor cell suspension after laparoscopic surgery in an experimental model.

METHODS

Forty C57 bl6 mice underwent laparoscopy with CO(2) insufflation and instillation of a MB 49 syngenic urothelial tumor cell suspension into the abdominal cavity. Mice were randomly allocated to one of the following groups (n=10 mice per group), and all agents were administrated intraperitoneally: (1) control (phosphate-buffered saline); (2) unspecific oligopeptides; (3) specific oligopeptides; (4) mitomycin. The mice were sacrificed 14 d after the procedure, and the peritoneal cavity and port sites examined for the presence of tumor.

RESULTS

A significant reduction in tumor implantation and port-site metastases was observed in all treatment groups (specific oligopeptides and mitomycin). The oligopeptide group showed the best performance regarding body weight.

CONCLUSIONS

This study suggests that tumor implantation after laparoscopic surgery and port-site metastases might be prevented by the intraperitoneal administration of specific oligopeptides or cytotoxic agents. Moreover, oligopeptides, in comparison with mitomycin, caused less weight loss of the mice.