Metabolism and pulmonary toxicity of cyclophosphamide

Drug reactive metabolite-induced hepatotoxicity: a comprehensive review

Nowadays, drug-induced liver toxicity (DILT) is one of the main contributing factors to severe liver disease. In the United States (US) alone, DILT is the cause of more than 50% of instances of acute liver failure. Prescription or over-the-counter drugs, xenobiotics, and herbal and nutritional supplements can cause DILT and could produce anomalies in hepatic function tests. Some drugs induce hepatotoxicity directly, and others induce it indirectly (i. e. through their toxic or reactive metabolites). Currently, the United States Food and Drug Administration (US FDA) has issued black box warnings for about 1279 drugs due to their hepatotoxicity. When we analyzed their mechanism in inducing hepatotoxicity, we found nearly 18 drugs causing hepatotoxicity by their toxic metabolites. In this review, we attempted to highlight the well-known drugs that induce hepatotoxicity indirectly through their toxic metabolites including the enzymes involved in the formation of these metabolites. The Cytochrome P-450 (CYP), Hypoxanthine phosphoribosyltransferase 1, Alcohol oxidase, Uridine diphosphate (UDP)-glucuronosyltransferases, Xanthine dehydrogenase, Purine-nucleoside phosphorylase, Xanthine oxidase, Thiopurine S-methyltransferase, Inosine-5'-monophosphate dehydrogenase, and aldehyde dehydrogenase are involving in the formation of toxic metabolites. The metabolic reactions and enzymes discussed in this review help toxicologists, pharmacologists, and chemists to design and develop hepatotoxicity-free pharmaceutical products containing the inhibitors of these enzymes to reduce hepatotoxicity and improve human health.

Drug-microbiota interactions: an emerging priority for precision medicine

Individual variability in drug response (IVDR) can be a major cause of adverse drug reactions (ADRs) and prolonged therapy, resulting in a substantial health and economic burden. Despite extensive research in pharmacogenomics regarding the impact of individual genetic background on pharmacokinetics (PK) and pharmacodynamics (PD), genetic diversity explains only a limited proportion of IVDR. The role of gut microbiota, also known as the second genome, and its metabolites in modulating therapeutic outcomes in human diseases have been highlighted by recent studies. Consequently, the burgeoning field of pharmacomicrobiomics aims to explore the correlation between microbiota variation and IVDR or ADRs. This review presents an up-to-date overview of the intricate interactions between gut microbiota and classical therapeutic agents for human systemic diseases, including cancer, cardiovascular diseases (CVDs), endocrine diseases, and others. We summarise how microbiota, directly and indirectly, modify the absorption, distribution, metabolism, and excretion (ADME) of drugs. Conversely, drugs can also modulate the composition and function of gut microbiota, leading to changes in microbial metabolism and immune response. We also discuss the practical challenges, strategies, and opportunities in this field, emphasizing the critical need to develop an innovative approach to multi-omics, integrate various data types, including human and microbiota genomic data, as well as translate lab data into clinical practice. To sum up, pharmacomicrobiomics represents a promising avenue to address IVDR and improve patient outcomes, and further research in this field is imperative to unlock its full potential for precision medicine.

Exogenous Apelin-13 Administration Ameliorates Cyclophosphamide- Induced Oxidative Stress, Inflammation, and Apoptosis in Rat Lungs

BACKGROUND

Apelin-13 is an endogenous adipocytokine known for its antioxidant, antiinflammatory, and antiapoptotic properties.

OBJECTIVE

We aimed to investigate the possible protective effects of exogenous Apelin-13 administration on oxidative stress, inflammation, and apoptosis induced by the cytotoxic agent cyclophosphamide (CP) in the lungs.

METHODS

Twenty-four male Wistar albino rats were divided into four groups: Control (saline), CP (200 mg/kg), Apelin-13 (10 μg/kg/day), and CP+Apelin-13. CP was administered as a single dose on the fifth day, and apelin-13 was administered intraperitoneally for five days. Total oxidant status (TOS), total antioxidant status (TAS), and lipid peroxidation were determined with spectrophotometry, TNFα and IL1β were determined with ELISA, APJ, Sirt1, NF-κB, and p53 mRNA expressions were determined with qRT-PCR, cytochrome (Cyt) C and caspase-3 protein expressions were studied with western blotting in lung tissues. The oxidative stress index (OSI) was also calculated. Furthermore, serum surfactant protein-D (SP-D) and Krebs von den Lungen-6 (KL-6) levels were measured with ELISA.

RESULTS

Compared to the control group, TOS, OSI, lipid peroxidation, TNFα, IL1β, cyt C, caspase-3, APJ, NF-κB, and p53 were higher, and Sirt1 was lower in the lung tissue of rats in the CP group. Serum KL-6 and SP-D levels were higher in the CP group. Co-administration of CP with Apelin-13 completely reversed the changes induced by CP administration.

CONCLUSION

Exogenous Apelin-13 treatment protected lung tissue against injury by inhibiting cyclophosphamide-induced oxidative stress, inflammation, and apoptosis. This protective effect of apelin-13 was accompanied by upregulation of the Sirt1 and downregulation of NF-κB/p53 in the lungs.

Rare Case of Reversible Pulmonary Arterial Hypertension Secondary to Cyclophosphamide and Doxorubicin Chemotherapy

Pulmonary arterial hypertension (PAH), characterized as a resting mean pulmonary artery pressure greater than 25 mmHg, is due to the narrowing of the pulmonary arteries, which can be idiopathic, inherited, or drug-related. Alkylating agents, including cyclophosphamide, are a risk factor for developing the pulmonary veno-occlusive disease. Drug-induced PAH is extremely rare. A 59-year-old female with newly diagnosed invasive ductal carcinoma of the right breast and high-grade ductal carcinoma in situ of the left breast was initiated treatment with doxorubicin and cyclophosphamide. About one week after receiving the first cycle, the patient developed worsening lower extremity edema and shortness of breath. She was then hospitalized, and a transthoracic echocardiogram and coronary angiogram revealed PAH. The team then changed the breast cancer treatment regimen to Taxol and carboplatin, and PAH was resolved in a follow-up echocardiogram after five months. This report has described the first case of PAH directly related to cyclophosphamide and doxorubicin. It is imperative to promptly recognize this rare but important side-effect as early diagnosis and response can potentially reverse the disease progression.

Amelioration of cyclophosphamide toxicity via modulation of metabolizing enzymes by avocado (Persea americana) extract

OBJECTIVES

Cyclophosphamide (CPA) is highly effective in treating several human tumours and autoimmune disorders; but, it triggers deleterious side effects. Avocado, Persea americana (Mill.), is a widely consumed fruit with pronounced nutritional and medicinal value. Though many studies examined the protective mechanisms of natural products against CPA toxicity, almost none investigated the modulation of CPA metabolism as a potential underlying mechanism for protection. Here, we investigated the modulating effect of avocado extract (AE) on certain CPA metabolizing enzymes and its correlation with the extent of CPA-induced pulmonary toxicity and urotoxicity.

METHODS

Rats received oral AE (0.9 g/kg body weight/day) 7 days before a single CPA injection (150 mg/kg body weight) and continued AE intake for 2, 7 or 28 days to study three phases of CPA-induced urotoxicity and pulmonary toxicity.

KEY FINDINGS

CPA acutely elevated then reduced hepatic microsomal cytochrome P450 2B6 (CYP2B6) content and significantly suppressed bladder and lung glutathione-S-transferase activity. Furthermore, CPA elevated lung myeloperoxidase activity, DNA content and hydroxyproline level and bladder blood content. AE ameliorated CPA-induced derangements through suppression of CYP2B6 and myeloperoxidase and augmentation of glutathione-S-transferase activity in CPA-treated rats.

CONCLUSIONS

AE modulation of CPA metabolizing enzymes and potential anti-inflammatory effect may mitigate CPA-induced toxicity.

Sesamol Alleviates the Cytotoxic Effect of Cyclophosphamide on Normal Human Lung WI-38 Cells via Suppressing RAGE/NF-κB/Autophagy Signaling

Cyclophosphamide (CYL) is a chemotherapeutic medication commonly used in managing various malignancies like breast cancer or leukemia. Though, CYL has been documented to induce lung toxicity. Mechanism of CYL toxicity is through oxidative stress and the release of damage-associated molecular patterns (DAMPs). Sesamol (SES) is a natural antioxidant isolated from Sesamum indicum and its effect against CYL-induced lung toxicity is not studied yet. This study aims to investigate whether SES could prevent any deleterious effects induced by CYL on lung using normal human lung cells, WI-38 cell line, without suppressing its efficacy. Cells were pretreated with SES and/or CYL for 24 h, then cell viability was estimated by MTS and trypan blue assays. The mode of cell death was determined by AO/EB staining. Additionally, caspase-3 level, oxidative stress, and inflammatory markers were evaluated by colorimetric and ELISA techniques. qRT-PCR was performed to evaluate RAGE, NF-κB, and Beclin-1 mRNA-expression. CYL-treated WI-38 cells developed a significantly increased cell death with enhanced oxidative and RAGE/NF-κb/Autophagy signaling, which were all attenuated after pretreatment with SES. Thus, we concluded that SES offered a protective role against CYL-induced lung injury via suppressing oxidative stress and RAGE/NF-κB/Autophagy signaling, which is a natural safe therapeutic option against CYL toxicities.

Cyclophosphamide for salvage therapy of chronic graft-versus-host disease: a retrospective analysis

We retrospectively analyzed the safety and efficacy of cyclophosphamide (cyclo) for salvage treatment of chronic graft-versus-host disease (cGvHD) and cGvHD-associated (glomerulo-)nephritis at our center between 01/2010 and 11/2019. We identified 13 patients (pts) receiving cyclo for treatment of moderate (3/13) and severe (6/13) steroid-refractory cGvHD, cGvHD-associated (glomerulo-)nephritis (3/13), or vasculitis-like CNS manifestation of cGvHD (1/13). Cyclo was started on median day 509 (range 42-8193) after cGvHD onset; the median duration of application was 153 days (range 14-486) with 2/13 currently continuing treatment. The National Institute of Health organ grading and the intensity of immunosuppression (IS) were assessed at cyclo start and repeated after 3, 6, and 12 months. Response assessment was stopped at the start of any additional new IS. The median time of follow up was 407 days (range 86-1534). Best response was 1/13 CR, 6/13 PR, 4/13 SD, 1/13 MR, and 1/13 PD (ORR 54%). Significant and durable response was observed especially in cGvHD-associated (glomerulo-)nephritis (3/3). Infectious complications > CTCAE grade III were observed in 3/12 pts. During cyclo therapy, none of the pts suffered from recurrence of underlying malignancy. Overall, cyclo was relatively well tolerated and showed responses in heavily pretreated patients but requires further evaluation within clinical trials.

An immunohistochemical study of the effects of various antioxidants on rat lung during chemotherapy

We investigated using immunohistochemistry the possible protective effects of ascorbic acid, α-tocopherol and selenium during chemotherapy treatment with cyclophosphamide. Thirty female Wistar rats were divided into five groups of six: group 1, untreated control; group 2, 75 µg/kg cyclophosphamide; group 3, 75 µg/kg cyclophosphamide + 150 µg/kg/day α-tocopherol; group 4, 75 µg/kg cyclophosphamide + 200 µg/kg/day ascorbic acid and group 5, 75 µg/kg cyclophosphamide + 40 ppm/kg/day selenium. Proliferating cell nuclear antigen (PCNA) staining was used to detect cell proliferation and AT₁ was used to evaluate structural damage. Caspase-8, caspase-9 and caspase-3 signal molecules were used to investigate apoptosis. In group 2, epithelium, alveolar macrophages, infiltrated lymphocytes and connective tissue were immunostained moderately to strongly with PCNA. Bronchus, alveolar wall and infiltrated lymphocytes were immunostained moderately to strongly with AT₁ and diffuse strong caspase immunoreactions were observed throughout the lung tissue. AT₁ and caspase immunoreactions in groups 4 and 5 were similar to group 2. In group 3, PCNA immunoreactivity was strong in the bronchiolus epithelium, endothelial cell nuclei and in stacks of infiltrated lymphocyte cell nuclei. In group 3, AT₁ and caspase immunoreactions were identical to group 1. It appears that α-tocopherol inhibits lung tissue damage in rats during chemotherapy.

Curcumin Prevents Cyclophosphamide-Induced Lung Injury in Rats by Suppressing Oxidative Stress and Apoptosis

Curcumin (CUR) has been used since ancient times to treat several ailments as it possesses many pharmacological activities. This study intended to explore the mechanism underlying the protective effects of CUR in remodeling oxidative stress and apoptotic signals in cyclophosphamide (CP)-induced pulmonary injury in albino rats. CUR was administered at a dose of 300 mg/kg/day for 7 days and on the seventh day a single dose of CP (200 mg/kg) was given. Histopathological and ultrastructural examinations of CP-intoxicated rats showed complete alveolar obstruction, thickened inter-alveolar septa, enlarged blood vessels, severe inflammatory edema with pyknotic nuclei, and disappearance of cytoplasmic organelles. Significant increases in caspase-3, malondialdehyde (MDA), and protein carbonyl (PCO) and significant decreases in superoxide dismutase (SOD) and glutathione peroxidase (GPx) were observed. In contrast, rats that received CUR showed clear and empty lumina with single row of pneumocytes, disappearance of edema, and no interstitial electron dense bodies in rats’ lung tissues. Additionally, CUR significantly reduced caspase-3, MDA, and PCO and increased SOD and GPx. In conclusion, these findings revealed the protective effects of CUR against CP-induced pulmonary injury in rats through suppressing oxidative damage and apoptosis.

Genetic susceptibility, residential radon, and lung cancer in a radon prone area

INTRODUCTION

Radon exposure has been classified as the second cause of lung cancer, after tobacco, and the first in never smokers. GSTM1 and GSTT1 genes deletion increase the risk of lung cancer. We aim to know whether the risk of lung cancer because of residential radon is modulated by these genetic polymorphisms.

METHODS

Hospital-based, case-control study where cases had confirmed lung cancer. Cases and controls did not have previous neoplasm and were older than 30. Controls attended hospital for noncomplex surgery. We analyzed the results for the whole sample and separately for never/light smokers and moderate/heavy smokers.

RESULTS

Seven-hundred and ninety-two participants were analyzed. GSTM1 and GSTT1 deletion conferred an odds ratio (OR) of 1.38 (95% confidence interval [CI] 0.93-2.04) and 1.13 (95% CI 0.70-1.82), respectively. Individuals with GSTM1 present and residential radon concentrations higher than 148 Bq/m had an OR of 1.48 (95% CI 0.73-3.00), whereas those with GSTM1 deleted had an OR of 2.64 (95% CI 1.18-5.91) when compared with participants with GSTM1 present and radon concentrations below 50 Bq/m3. Similar results were observed for GSTT1 deletion. These results were basically the same for the moderate/heavy smokers' subgroup.

CONCLUSIONS

The absence of GSTM1 and GSTT1 genes increases the risk of lung cancer because of radon exposure. These genes might modulate the carcinogenic pathway of alpha radiation. Further studies are warranted analyzing this association in never smokers.

An ethanol extract of Origanum vulgare attenuates cyclophosphamide-induced pulmonary injury and oxidative lung damage in mice

CONTEXT

Injury to normal tissues is the major limiting side effect of using cyclophosphamide (CP), an antineoplastic alkylating compound.

OBJECTIVE

This study was undertaken to evaluate the protective effect of an extract of Origanum vulgare L. (Lamiaceae), an antioxidative medicinal plant, against CP-induced oxidative lung damage in mice.

MATERIALS AND METHODS

Mice were pre-treated with various doses of O. vulgare extract (50, 100, 200, and 400 mg/kg) for 7 consecutive days followed by an injection with CP (200 mg/kg b.w.) One hour after the injection of O. vulgare on the last day, mice were injected with CP; 24 h later, they were euthanized, their lungs were immediately removed, and biochemical and histological studies were conducted.

RESULTS

A single dose of CP markedly altered the levels of several biomarkers associated with oxidative stress in lung homogenates. Pretreatment with O. vulgare significantly reduced the levels of lipid peroxidation and attenuated the alterations in glutathione content and superoxide dismutase activity induced by CP in lung tissue. In addition, O. vulgare effectively alleviated CP-induced histopathological changes in lung tissue.

CONCLUSIONS

Our results revealed that O. vulgare protects lung tissues from CP-induced pulmonary damage and suggest a role for oxidative stress in the pathogenesis of lung disease produced by CP. Because O. vulgare has been extensively used as an additive agent and is regarded as safe, it may be used concomitantly as a supplement for reducing lung damage in patients undergoing chemotherapy.

Oxyhalogen-sulfur chemistry: kinetics and mechanism of oxidation of chemoprotectant, sodium 2-mercaptoethanesulfonate, MESNA, by acidic bromate and aqueous bromine

The oxidation of a well-known chemoprotectant in anticancer therapies, sodium 2-mercaptoethanesulfonate, MESNA, by acidic bromate and aqueous bromine was studied in acidic medium. Stoichiometry of the reaction is: BrO3(-) + HSCH2CH2SO3H → Br(-) + HO3SCH2CH2SO3H. In excess bromate conditions the stoichiometry was deduced to be: 6BrO3(-) + 5HSCH2CH2SO3H + 6H(+) → 3Br2 + 5HO3SCH2CH2SO3H + 3H2O. The direct reaction of bromine and MESNA gave a stoichiometric ratio of 3:1: 3Br2 + HSCH2CH2SO3H + 3H2O → HO3SCH2CH2SO3H + 6Br(-) + 6H(+). This direct reaction is very fast; within limits of the mixing time of the stopped-flow spectrophotometer and with a bimolecular rate constant of 1.95 ± 0.05 × 10(4) M(-1) s(-1). Despite the strong oxidizing agents utilized, there is no cleavage of the C-S bond and no sulfate production was detected. The ESI-MS data show that the reaction proceeds via a predominantly nonradical pathway of three consecutive 2-electron transfers on the sulfur center to obtain the product 1,2-ethanedisulfonic acid, a well-known medium for the delivery of psychotic drugs. Thiyl radicals were detected but the absence of autocatalytic kinetics indicated that the radical pathway was a minor oxidation route. ESI-MS data showed that the S-oxide, contrary to known behavior of organosulfur compounds, is much more stable than the sulfinic acid. In conditions where the oxidizing equivalents are limited to a 4-electron transfer to only the sulfinic acid, the products obtained are a mixture of the S-oxide and the sulfonic acid with negligible amounts of the sulfinic acid. It appears the S-oxide is the preferred conformation over the sulfenic acid since no sulfenic acids have ever been stabilized without bulky substituent groups. The overall reaction scheme could be described and modeled by a minimal network of 18 reactions in which the major oxidants are HOBr and Br2(aq).

The ethanol extract of the inner bark of Caesalpinia pyramidalis (Tul.) reduces urinary bladder damage during cyclophosphamide-induced cystitis in rats

Hemorrhagic cystitis (HC) is a common side effect of cyclophosphamide therapy, which deserves new therapeutic strategies, such as those based on natural products. The ethanol extract of the inner bark of Caesalpinia pyramidalis (Tul.) (EECp) possesses anti-inflammatory, antinociceptive, and antioxidant activities as previously showed by our group. We have investigated the effect of EECp on the cyclophosphamide-induced HC. Cystitis was induced in male Wistar rats by the injection of cyclophosphamide. These animals were pretreated with EECp (100-400 mg/kg), vehicle, or mesna. Myeloperoxidase activity and malondialdehyde formation were measured in urinary bladder and other tissues. Bladder edema and histopathological alterations and serum nitric oxide metabolites concentration NOx- were also evaluated. Treatment with EECp (100-400 mg/kg) or mesna impaired the increase of myeloperoxidase activity in urinary bladder and the serum NOx- induced by cyclophosphamide but did not reduce edema in this tissue, as did mesna. Total histological score was reduced by EECp (100 mg/kg). Lung myeloperoxidase activity, which was increased by cyclophosphamide, was decreased significantly by EECp (400 mg/kg). EECp also diminished the malondialdehyde formation in bladder, lung, and spleen, although these parameters were not affected by cyclophosphamide. These results indicate that EECp reduced urinary bladder damage during cyclophosphamide-induced HC in rats.

Protective effects of Zhuyeqing liquor on the immune function of normal and immunosuppressed mice in vivo

Background

Zhuyeqing Liquor (ZYQL), a well-known Chinese traditional health liquor, has various biological properties, including anti-oxidant, anti-inflammatory, immunoenhancement and cardiovascular protective effects.

Methods

The protective effects of Zhuyeqing Liquor (ZYQL) on the immune function was investigated in vivo in normal healthy mice and immunosuppressed mice treated with Cyclophosphamide (Cy, 100 mg/kg) by intraperitoneal injection on days 4, 8 and 12. ZYQL (100, 200 and 400 mg/kg) was administered via gavage daily for 14 days. The phagocytotic function of mononuclear phagocytic system was detected with carbon clearance methods, the levels of interleukin-6 (IL-6) and interferon-gamma (IFN-γ) in serum were detected with Enzyme linked immunosorbent assay (ELISA). Immune organs were weighed and organ indexes (organ weight/body weight) of thymus and spleen were calculated. Meanwhile, the activity of lysozyme (LSZ) in serum and the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) in spleen tissue were measured.

Results

ZYQL significantly upgrades the K value for clearance of carbon particles in normal mice treated with ZYQL (400 mg/kg) and immunosuppressed mice treated with ZYQL (100, 200 and 400 mg/kg) together with Cy (100 mg/kg) in vivo. The treatment of ZYQL (100, 200 and 400 mg/kg) effectively increased the activity of serum lysozyme as well as promoted the serum levels of IL-6 and IFN-γ in normal mice and immunosuppressed mice. Furthermore, ZYQL (100, 200 and 400 mg/kg) had an antioxidant effects in immune system by enhancing the antioxidant enzyme activity of SOD, CAT and GSH-Px in vivo. In addition, ZYQL (100, 200 and 400 mg/kg) effectively elevated the Cy-induced decreased organ index (thymus and spleen).

Conclusions

The present work shows that the dose-dependent administration of ZYQL is capable of influencing immune responses, which implying that its valuable functional health may be attributed partly to its protective effects for the immune function.

Modulation of cyclophosphamide-induced early lung injury by allicin

CONTEXT

Cyclophosphamide (CP) causes lung injury in rats through its ability to generate free radicals with subsequent epithelial and endothelial cell damage.

OBJECTIVE

This study was conducted to assess whether allicin can ameliorate CP-induced early lung injury in rats.

MATERIALS AND METHODS

Male Sprague Dawely rats were divided into four groups. Group I was the control group. Group II received allicin (50 mg/kg/d, p.o.) for 14 consecutive days. Group III was injected once with CP (150 mg/kg, i.p.). Group IV received allicin for seven consecutive days, before and after CP injection (150 mg/kg, i.p.). The parameters of study were serum biomarkers, lung tissue antioxidant profile and histopathological changes in lung tissue.

RESULTS

A single intraperitoneal injection of CP markedly altered the levels of several biomarkers in lung homogenates. Significant increases in lung content of lipid hydroperoxides were seen that paralleled the decreased levels of total reduced glutathione. Superoxide dismutase activity (SOD) was significantly increased. CP increased the level of serum biomarkers; total protein, lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-α). Pretreatment of rats daily with oral allicin seven days prior to and seven days after CP inject significantly inhibited the development of lung injury, prevented the alterations in lung and serum biomarkers associated with inflammatory reactions, with less lipid peroxidation (LP) and restoration of antioxidants. Moreover, allicin attenuated the secretion of proinflammatory cytokine, TNF-α expression in rat serum. In addition, allicin effectively blunted CP-induced histopathological changes in lung tissue.

DISCUSSION AND CONCLUSION

Our results suggest that allicin is efficient in blunting CP-induced pulmonary damage.

Acrolein-induced inflammatory signaling in vascular smooth muscle cells requires activation of serum response factor (SRF) and NFκB

BACKGROUND

Modulation of inflammatory signaling has been elucidated in several disease models. Acrolein, an environmental pollutant, has been linked to diseases such as atherosclerosis and to the inflammatory process involving nuclear factor κB (NFκB). Serum response factor (SRF), a transcription factor, regulates cell development, differentiation and proliferation through signaling molecules such as extracellular signal-regulated kinase 1/2 (ERK1/2) and CD36. We hypothesized that acrolein toxicity involves SRF in the process of activating NFκB and may involve CD36/ERK1/2.

METHODS

Vascular smooth muscle cells (VSMCs) were exposed to acrolein (0.5 μg/mL) in the presence or absence of 10 nM QNZ (NFκB inhibitor), 300 nM CCG1423 (SRF inhibitor) and 50 μM PD98059 (ERK1/2 inhibitor). Protein and RNA were isolated. Changes in expression were determined by Western blot and polymerase chain reaction (PCR) array.

RESULTS

Subtoxic doses of acrolein increased ERK1/2, SRF and NFκB protein expression, whereas CD36 expression was unchanged. Increase in NFκB expression was accompanied by an increase in activity. ERK1/2 inhibition only blunted SRF expression. SRF inhibition blunted NFκB expression but not that of ERK1/2. CD36 expression was unchanged in the presence of either inhibitor. PCR array analysis indicated up-regulation of nine genes (>4- to 50-fold) and down-regulation of six genes (>4- to 12-fold) involved in inflammatory signaling.

CONCLUSIONS

We propose that SRF is required in acrolein activation of NFκB and is ERK1/2 dependent.

Concurrent decline of several antioxidants and markers of oxidative stress during combination chemotherapy for small cell lung cancer

OBJECTIVES

To investigate the oxidant effects of adriamycin-containing chemotherapy (CT), we evaluated various antioxidants, total antioxidant capacity (TRAP) and different parameters of oxidative and nitrosative stress during combination CT.

DESIGN AND METHODS

Blood samples were obtained from 16 small cell lung cancer patients at baseline and several times during the first, second and sixth CT cycles.

RESULTS

There were significant decreases in serum urate and serum proteins during all cycles, serum TRAP during the first two cycles, plasma ascorbic acid and serum TBARS during the first cycle, and serum conjugated dienes and plasma alphatocopherol during the last cycle. The baseline levels of tocopherols increased significantly between the first and sixth CT cycles. Higher levels of baseline plasma thiols were associated with better overall survival (p=0.008).

CONCLUSIONS

Adriamycin-containing CT causes significant oxidative stress as implied by reduced levels of protective antioxidants. Long-term CT treatment seems to enhance lipid peroxidation.

Cyclophosphamide-induced acute respiratory distress syndrome

Cyclophosphamide is widely used in neoplastic and inflammatory diseases. Although several adverse events have been described with its use, acute and subacute interstitial pneumonitis leading to pulmonary fibrosis is rare and potentially fatal. This case report describes a 64-year-old man who, after the fifth chemotherapy cycle, developed a severe ARDS leading to pulmonary fibrosis in just 30 days.

Kinetics and mechanism of protein tyrosine phosphatase 1B inactivation by acrolein

Human cells are exposed to the electrophilic alpha,beta-unsaturated aldehyde acrolein from a variety of sources. The reaction of acrolein with functionally critical protein thiol residues can yield important biological consequences. Protein tyrosine phosphatases (PTPs) are an important class of cysteine-dependent enzymes whose reactivity with acrolein previously has not been well-characterized. These enzymes catalyze the dephosphorylation of phosphotyrosine residues on proteins via a phosphocysteine intermediate. PTPs work in tandem with protein tyrosine kinases to regulate a number of critically important mammalian signal transduction pathways. We find that acrolein is a potent time-dependent inactivator of the enzyme PTP1B ( k inact = 0.02 +/- 0.005 s (-1) and K I = 2.3 +/- 0.6 x 10 (-4) M). The enzyme activity does not return upon gel filtration of the inactivated enzyme, and addition of the competitive phosphatase inhibitor vanadate slows inactivation of PTP1B by acrolein. Together, these observations suggest that acrolein covalently modifies the active site of PTP1B. Mass spectrometric analysis reveals that acrolein modifies the catalytic cysteine residue at the active site of the enzyme. Aliphatic aldehydes such as glyoxal, acetaldehyde, and propanal are relatively weak inactivators of PTP1B under the conditions employed here. Similarly, unsaturated aldehydes such as crotonaldehyde and 3-methyl-2-butenal bearing substitution at the alkene terminus are poor inactivators of the enzyme. Overall, the data suggest that enzyme inactivation occurs via conjugate addition of the catalytic cysteine residue to the carbon-carbon double bond of acrolein. The results indicate that inactivation of PTPs should be considered as a possible contributor to the diverse biological activities of acrolein and structurally related alpha,beta-unsaturated aldehydes.

Acrolein induces axolemmal disruption, oxidative stress, and mitochondrial impairment in spinal cord tissue

Acrolein, a byproduct of oxidative stress and lipid peroxidation, has been implicated in neurodegenerative disorders such as Alzheimer's disease, but not in spinal cord trauma, as a possible key factor in neuronal degeneration. Using an isolated guinea pig spinal cord model, we have found that acrolein, in a dose- and time-dependent manner, inflicts severe membrane disruption, a factor thought to be critical in triggering axonal deterioration and cell death. The concentration threshold of such detrimental effect is shown to be around 1 microM when acrolein was exposed for 4 h. The membrane damage is likely mediated in part by reactive oxygen species and lipid peroxidation, which were elevated in response to acrolein exposure. Antioxidants were able to significantly reduce acrolein-mediated membrane disruption which further supports the role of reactive oxygen species in the loss of membrane integrity. Mitochondrial function was also impaired after acrolein exposure which not only implicates but emphasizes the role of this organelle in reactive oxygen species generation. In summary, our data strongly suggest that at a clinically relevant concentration, acrolein can severely compromise membrane integrity and may further serve as an initiating toxin triggering secondary injury cascades following the initial physical insult to the spinal cord.

Glutathione S-transferases (GSTT1 and GSTM1) gene deletions in Tunisians: susceptibility and prognostic implications in breast carcinoma

Glutathione S-transferase Theta1 and Mu1 (GSTT1 and GSTM1) are involved in the metabolism and detoxification of a wide range of potential environmental carcinogens. Conversely, they contribute to tumour cell survival by detoxification of numerous products induced by cancer therapy. The authors designed a large study to investigate the susceptibility and prognostic implications of the GSTT1 and GSTM1 gene deletions in breast carcinoma. The authors used the polymerase chain reaction to characterise the variation of the GSTT1 and GSTM1 genes in 309 unrelated Tunisian patients with breast carcinoma and 242 healthy control subjects. Associations of the clinic-pathologic parameters and the genetic markers with the rates of the breast carcinoma specific overall survival (OVS) and the disease-free survival (DFS) were assessed using univariate and multivariate analyses. A significant association was found between gene deletion of GSTT1 and the risk of early onset of breast carcinoma (OR=1.60, P=0.02). The lack of GSTT1 gene deletion was significantly associated with poor clinical response to chemotherapy (OR=2.29, P=0.03). This association was significantly higher in patients with axillary's lymph node-negative breast carcinoma (OR=12.60, P=0.005). The null-GSTT1 genotype showed a significant association with increased DFS in this selected population of patients. This association was even higher in patients carrying both null-GSTT1 and -GSTM1 genotypes. The gene deletion of GSTs may predict not only the early onset of breast carcinoma but also the clinical response to chemotherapy and the recurrence-free survival for patients with lymph node-negative breast carcinoma.

Cyclophosphamide decreases nitrotyrosine formation and inhibits nitric oxide production by alveolar macrophages in mycoplasmosis

We previously reported that congenic C57BL/6 inducible nitric oxide synthase(-/-) (iNOS(-/-)) mice infected with Mycoplasma pulmonis developed higher bacterial numbers and lung lesion scores than C57BL/6 iNOS(+/+) controls but had similar lung nitrotyrosine levels. The present studies investigated the role of inflammatory cells in nitrotyrosine formation during mycoplasmal infection. iNOS(+/+) and iNOS(-/-) mice were injected with cyclophosphamide (CYP) and inoculated with 10(7) CFU of M. pulmonis. CYP pretreatment of M. pulmonis-infected iNOS(+/+) and iNOS(-/-) mice reduced polymorphonuclear cells (PMNs) within bronchoalveolar lavages (BALs) by 88 and 72%, respectively, and whole-lung myeloperoxidase levels by 80 and 78%, respectively, at 72 h postinfection but did not alter the number of alveolar macrophages (AMs) in BALs. CYP treatment also significantly decreased nitrate and nitrite (NOx) levels in BALs and plasma of infected iNOS(+/+) mice, whereas neither CYP nor mycoplasmal infection altered NOx in iNOS(-/-) mice. CYP reduced lung nitrotyrosine levels in both iNOS(+/+) and iNOS(-/-) mice to uninfected-control levels as shown by immunohistochemical staining and enzyme-linked immunosorbent assay and inhibited mycoplasmal killing by iNOS(+/+) mice in vivo. CYP inhibited the production of gamma interferon-inducible NOx by iNOS(+/+) AMs in vitro but did not alter the number of iNOS-positive AMs, as detected by immunocytochemistry. In addition, AMs from CYP-treated iNOS(+/+) mice had significantly decreased ability to kill mycoplasmas in vitro. These results demonstrate that reactive species generated by inflammatory cells as well as PMN myeloperoxidase are important contributors to nitrotyrosine formation during mycoplasmal infection and that treatment with CYP decreases NO* production by AMs and inhibits mycoplasmal killing.

Dual role of vitamin C on lipid profile and combined application of cyclophosphamide, methotrexate and 5-fluorouracil treatment in fibrosarcoma-bearing rats

Combined application of cyclophosphamide, methotrexate, 5-fluorouracil (CMF) has been followed in the treatment of breast cancer. The combined effect of CMF and vitamin C on plasma lipid and lipoprotein is important, since vitamin C encumbers the lipid abnormalities instigated by CMF. Hence, the study was launched to appraise the salubrious role of vitamin C in CMF administered fibrosarcoma-bearing rats. Fibrosarcoma cell line-induced rats were treated with CMF (cyclophosphamide 10 mg/kg b.w., methotrexate 1 mg/kg b.w., 5-fluorouracil 10 mg/kg b.w. and vitamin C 200 mg/kg b.w.) individually and in combination for 120 days. The concentration of plasma lipids and lipoprotein was determined in control and experimental rats. The untreated as well as CMF administered fibrosarcoma-bearing rats divulged significantly in increased levels of plasma total cholesterol, triglycerides, phospholipids, very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol, as compared with their respective control animals. Whereas ester and high density lipoprotein (HDL) cholesterol levels exhibited a marked decrease in these animals. However, these lipid abnormalities were found to be moderated by co-administration of vitamin C. These results suggested that some clinical entanglement of CMF was refrained by co-administration of vitamin C in tumor stress condition.

Cyclophosphamide-induced generation of reactive oxygen species. Comparison with morphological changes in type II alveolar epithelial cells and lung capillaries

Cyclophosphamide (CP) causes lung toxicity in animals and humans. The mechanisms of pulmonary damage caused by CP are not fully understood. Possibilities include direct toxicity to pulmonary tissue or indirect toxicity through activation of pulmonary inflammatory cells. The aim of the present study was the ultrastructural analysis (in transmission electron microscope) of the changes following CP administration within the structures forming the interalveolar septum of the lungs, particularly type II epithelial cells. An attempt was also made to reveal a correlation between the morphological changes, intensity of lipid peroxidation in lung tissue homogenates and blood serum collected from the left ventricle of the heart and the alterations in the activities of superoxide dismutase (Cu, Zn-SOD) and glutathione reductase (GSSG-R). The experiment used 40 male Wistar rats of 160-180 g body weight (b.w.). The animals were divided into two groups. Group I - (20 animals) were given single intraperitoneal (i.p.) dose of 150 mg CP/1 kg b.w./1 ml PBS. Group II - (20 animals) were given single i.p. dose of 1 ml PBS. All experimental animals were sacrificed after 1 (subgroups I, II-1) and 7 (subgroups I, II-7) days of CP (or PBS) treatment. I.p. administration of CP caused an increase in lipid peroxidation products (MDA-malondialdehyde) in lung tissue homogenates especially in subgroup I-1 (p = 0.00174). No statistical differences, however, were noted in the blood serum MDA levels, although a statistically significant decrease was found in GSSG-R (p = 0.00174) and SOD (p = 0.00174) activities in the serum. The paper discusses a potential link between the findings of biochemical analysis and the morphological changes found within lung tissue. Pulmonary trombopoesis was indicated as a possible mechanism preventing a decrease in blood platelet count following CP administration.

Complications of cyclophosphamide therapy

Cyclophosphamide is a powerful immunosuppressive agent that is commonly used clinically to treat neoplastic and inflammatory diseases affecting various sites, including the head and neck. The pharmacology of cyclophosphamide is reviewed with an emphasis on its toxicities and strategies for minimizing therapeutic adverse effects. Principles of therapy are discussed and illustrated by the use of cyclophosphamide in the treatment of Wegener's granulomatosis, a form of systemic vasculitis with prominent head and neck manifestations.

Cyclophosphamide administered repeatedly to the male rat and as a single dose to the female rat. Its effects on hepatic and pulmonary P450 and associated enzymes

1. Two different aspects of the effects of the cytotoxic agent cyclophosphamide (CP) on rat P450 and associated enzymes have been examined. 2. First, the effects of CP, administered as a single 200 mg/kg dose, on hepatic and pulmonary P450 and some associated enzymes in the female rat have been investigated. Second, the effects of repeat doses of CP (40 mg/kg on days 0-4 with killing on days 5, 8 and 11) to the male rat have been examined. 3. CP decreased the activity of the female rat hepatic enzymes 2A1, 2C6 and/or 2C12 and 2E1, NADPH-P450 oxidoreductase and 17 beta-oxidoreductase and the pulmonary enzyme 2B, 7 days after its administration. The decreases in the activity of the enzymes 2E1 and NADPH-P450 oxidoreductase were accompanied by a corresponding change in the amount of enzyme protein indicating that the alteration in expression of these enzymes occurred via changes in transcription and/or translation or protein degradation. 4. CP also impaired its own activation 7 days after its administration to the female rat. 5. The change in female enzyme profile was accompanied by a reduction in the hormones oestradiol, T4 and T3 7 days after CP administration. 6. Despite an apparent trend for an increase in activity on day 5, a decrease on day 8 and a subsequent increase on day 11, repeat doses of CP to the male rat generally did not alter the P450 isoforms 2A2, 2B1, 2C11, 2E1 and 3A2 or 17 beta-oxidoreductase, NADPH-P450 oxidoreductase and steroid 5 alpha-reductase. 7. Chronic administration of CP to the male rat significantly reduced erythromycin demethylase and NADPH-P450 oxidoreductase 8 days following commencement of dosing and significantly increased 2A2 11 days following commencement of dosing. There was also a statistically significant increase in pulmonary 2B 5 days following commencement of dosing. 8. Plasma testosterone and TSH were unchanged following repeated dosing with CP while T3 was significantly decreased on days 5, 8 and 11 and T4 was significantly decreased on day 8.

Multiple cerebral hemorrhages as a possible complication of antiblastic treatment with cyclophosphamide, methotrexate and fluoruracil (CMF) for breast cancer

In this paper we describe the case of a patient who underwent left breast radical mastectomy and corresponding removal of her axillary lymphonodes, for an infiltrating lobular cancer with massive colonizing (16 of 19 lymphonodes examined), stage T2N2M0. During chemotherapy with cyclophosphamide, methotrexate and 5 fluoruracil (CMF), the patient presented a symptomatology characterized by anarthria and dysphagia. These symptoms were the consequences of multiple cerebral hemorrhages unrelated to alterations in the coagulation process. The temporal relation with the pharmacological treatment and the lack of other explanations of the induced phenomenon lead us to hypothesize a cytotoxic mechanism due to the CMP treatment.

Cyclophosphamide: review of its mutagenicity for an assessment of potential germ cell risks

Cyclophosphamide (CP) is used to treat a wide range of neoplastic diseases as well as some non-malignant ones such as rheumatoid arthritis. It is also used as an immunosuppressive agent prior to organ transplantation. CP is, however, a known carcinogen in humans and produces secondary tumors. There is little absorption either orally or intravenously and 10% of the drug is excreted unchanged. CP is activated by hepatic mixed function oxidases and metabolites are delivered to neoplastic cells via the bloodstream. Phosphoramide mustard is thought to be the major anti-neoplastic metabolite of CP while acrolein, which is highly toxic and is produced in equimolar amounts, is thought to be responsible for most of the toxic side effects. DNA adducts have been formed after CP treatment in a variety of in vitro systems as well as in rats and mice using 3H-labeled CP. 32P-postlabeling techniques have also been used in mice. However, monitoring of adducts in humans has not yet been carried out. CP has also been shown to induce unscheduled DNA synthesis in a human cell line. CP has produced mutations in base-pair substituting strains of Salmonella tryphimurium in the presence of metabolic activation, but it has been shown to be negative in the E. coli chromotest. It has also been shown to be positive in Saccharomyces cerevisiae in D7 strain for many endpoints but negative in D62.M for aneuploidy/malsegregation. It has produced positive responses in Drosophila melanogaster for various endpoints and in Anopheles stephensi. In somatic cells, CP has been shown to produce gene mutations, chromosome aberrations, micronuclei and sister chromatid exchanges in a variety of cultured cells in the presence of metabolic activation as well as sister chromatid exchanges without metabolic activation. It has also produced chromosome damage and micronuclei in rats, mice and Chinese hamsters, and gene mutations in the mouse spot test and in the transgenic lacZ construct of Muta Mouse. Increases in chromosome damage and gene mutations have been found in the peripheral blood lymphocytes of nurses, pharmacists and female workers occupationally exposured to CP during its production or distribution. Chromosome aberrations, sister chromatid exchanges and gene mutations have been observed in somatic cells of patients treated therapeutically with CP. In general, there is a maximum dose and an optimum time for the detection of genetic effects because the toxicity associated with high doses of CP will affect cell division. In germ cells, CP has been shown to induce genetic damage in mice, rats and hamsters although the vast majority of such studies have used male mice.(ABSTRACT TRUNCATED AT 400 WORDS)

Modulation of cyclophosphamide-induced early lung injury by curcumin, an anti-inflammatory antioxidant

Cyclophosphamide causes lung injury in rats through its ability to generate free radicals with subsequent endothelial and epithelial cell damage. In order to observe the protective effects of a potent anti-inflammatory antioxidant, curcumin (diferuloyl methane) on cyclophosphamide-induced early lung injury, healthy, pathogen free male Wistar rats were exposed to 20 mg/100 g body weight of cyclophosphamide, intraperitoneally as a single injection. Prior to cyclophosphamide intoxication oral administration of curcumin was performed daily for 7 days. At various time intervals (2, 3, 5 and 7 days post insult) serum and lung samples were analyzed for angiotensin converting enzyme, lipid peroxidation, reduced glutathione and ascorbic acid. Bronchoalveolar lavage fluid was analyzed for biochemical constituents. The lavage cells were examined for lipid peroxidation and glutathione content. Excised lungs were analyzed for antioxidant enzyme levels. Biochemical analyses revealed time course increases in lavage fluid total protein, albumin, angiotensin converting enzyme (ACE), lactate dehydrogenase, N-acetyl-beta-D-glucosaminidase, alkaline phosphatase, acid phosphatase, lipid peroxide levels and decreased levels of glutathione (GSH) and ascorbic acid 2, 3, 5 and 7 days after cyclophosphamide intoxication. Increased levels of lipid peroxidation and decreased levels of glutathione and ascorbic acid were seen in serum, lung tissue and lavage cells of cyclophosphamide groups. Serum angiotensin converting enzyme activity increased which coincided with the decrease in lung tissue levels. Activities of antioxidant enzymes were reduced with time in the lungs of cyclophosphamide groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Suppressing effect of WR-2721 on micronuclei induced by cyclophosphamide in mice

The effect of WR-2721 against cyclophosphamide-induced clastogenicity was studied using the in vivo micronucleus assay. The frequency of micronuclei in polychromatic erythrocytes in the peripheral blood of mice treated with WR-2721 and cyclophosphamide (CP), each of the compounds at a dose of 200 mg/kg body weight, was evaluated during the 15-day period. The suppressing effect of WR-2721, given 30 min prior to cyclophosphamide administration, on micronuclei induced by the alkylating agent was demonstrated. The number of micronuclei was increased on day 1 after CP application and declined thereafter with the frequency of micronucleated polychromatic erythrocytes remaining lower in WR-2721 pre-treated mice. The modulatory effect of WR-2721 on the clastogenic activity of cyclophosphamide in the erythropoietic system by the mouse micronucleus test was shown.

Fate and effects of acrolein

Acrolein is a highly toxic, reactive, and irritating aldehyde that occurs as a product of organic pyrolysis, as a metabolite of a number of compounds, and as a residue in water when used for the control of aquatic organisms. It is an intermediate in the production of acrylic acid, DL-methionine, and numerous other agents. Its major direct use is as a biocide for the control of aquatic flora and fauna. It is introduced to the environment from a variety of sources, including organic combustion such as automobile exhaust, cigarette smoke, and manufacturing and cooking emissions, as well as direct biocidal applications. Organic combustion from both fixed and mobile sources is the significant source of acrolein in the atmosphere; it represents up to 8% of the total aldehydes generated from vehicles and residential fireplaces and 13% of total atmospheric aldehydes. This reactive aldehyde also occurs in organisms as a metabolite of allyl alcohol, allylamine, spermine, spermidine, and the anticancer drug cyclophosphamide, and as a product of UV radiation of the skin lipid triolein. Furthermore, small amounts are found in foods; when animal or vegetable fats are overheated, however, large amounts are produced. Most human contact occurs during exposure to smoke from cigarettes, automobiles, industrial processes, and structural and vegetation fires. Besides cigarette smoke, occupational exposures are a common mode of human contact, particularly in industries that involve combustion of organic compounds. Firefighters, in particular, are exposed to extremely high levels during the extinguishment and overhaul phases of their work. Water may contain significant levels of the herbicide. It has been found in paper mill and municipal effluents at 20-200 micrograms/L, and at 30 micrograms/L as far as 64 km downstream from the point of application. The USEPA-recommended water quality criteria for freshwater are only 1.2 micrograms/L (24-hr avg) and 2.7 micrograms/L (maximum ceiling). Acrolein is highly reactive, and intercompartmental transport is limited. However, it is eliminated from aqueous environments by volatilization and hydration to beta-hydroxypropanal, after which biotransformation occurs, with a half-life of 7-10 d. The Koc for acrolein is 24, and it is not likely to be retained in soil; activated carbon adsorbs only 30% from solution. Thus, the aldehyde is either leached extensively in moist soil or volatilizes quickly from dry soil. It is eliminated from air by reaction with .OH (half-life, 0.5-1.2 d), NOx (half-life, 16 d), and O3 (half-life, 59 d), as well as by photolysis and wet deposition. As expected from its high water solubility, bioaccumulation is low. Acrolein is highly toxic by all routes of exposure. The respiratory system is the most common target: exposure causes localized irritation, respiratory distress, pulmonary edema, cellular necrosis, and increased susceptibility to microbial diseases. Additionally, acute inhalation studies verify that it is a severe respiratory irritant that affects respiratory rates. Respiratory rate depression may have a protective effect by minimizing vapor inhalation, thereby explaining the subadditive effect of acrolein when combined with the other toxic combustion by-products CO and HCHO. Liquid contact with the skin and eyes causes severe irritation, opaque or cloudy corneas, and localized epidermal necrosis, but no allergic contact dermatitis. The cardiovascular system is affected, resulting in increased blood pressure, platelet aggregation, and quick cessation of beating in perfused rat hearts. It may also inhibit mitochondrial oxidative phosphorylation in the myocardium. Acute LD50s and LC50s are low. Levels are 7-46 mg/kg and 18-750 mg/m3, respectively, in rats; aquatic organisms are affected above 11.4 micrograms/L.(ABSTRACT TRUNCATED)

In vivo administration of taurine and niacin modulate cyclophosphamide-induced lung injury

The antiinflammatory, antioxidant activity of taurine and niacin against cyclophosphamide-induced early lung injury in rats was investigated. A single intraperitoneal injection of cyclophosphamide markedly altered the levels of several biomarkers in bronchoalveolar lavage fluid: total protein, albumin, angiotensin converting enzyme, lactate dehydrogenase, lactate, N-acetyl-beta-D-glucosaminidase, alkaline phosphatase, acid phosphatase and lipid peroxidation product were significantly elevated. In contrast, decreased levels of total reduced glutathione (GSH) and ascorbic acid were observed. Cyclophosphamide significantly increased malondialdehyde levels in serum and lung. Significant increases in lung content of lipid hydroperoxides were seen that paralleled the decreased levels of total reduced glutathione and total sulfhydryl groups. Pretreatment of rats with daily intraperitoneal injection of taurine plus niacin 7 days prior to and 2 days after cyclophosphamide insult significantly inhibited the development of lung injury, prevented the alterations in lavage fluid biomarkers associated with inflammatory reactions, with less lipid peroxidation and restoration of antioxidants. In conclusion, our results suggest that taurine and niacin in combination is efficient in blunting cyclophosphamide-induced pulmonary damage.

Acute pneumocyte injury, poly(ADP-ribose) polymerase activity, and pyridine nucleotide levels after in vitro exposure of murine lung slices to cyclophosphamide

Cyclophosphamide (CYC) is a metabolically activated, DNA-alkylating, antitumor agent that causes pulmonary fibrosis. BALB/cN (B) mice are sensitive and C57Bl/6N (C) mice are resistant to CYC-induced fibrosis. Pulmonary bioactivation may contribute to strain sensitivity. Therefore, we tested the intrinsic susceptibility of murine lung slices to cell injury by direct exposure to CYC for 2-8 hr. Injury was measured by release of lactate dehydrogenase (LDH). DNA damage activates the nuclear enzyme poly(ADP-ribose) polymerase (PAP, EC 2.4.2.30), causing depletion of its substrate, NAD. NAD can also be decreased by phosphorylation to NADP, as seen with oxidative stress. Depletion of NAD can lead to loss of ATP. Thus, we measured LDH release, PAP activation, NAD, NADP and ATP in slices incubated with or without the PAP-inhibitor, 3-aminobenzamide (3-AB). CYC (0.1 to 1.0 mg/mL for 4-8 hr) caused LDH release in slices from both murine strains, but LDH release was significantly greater in B lung slices than in C slices. After an 8-hr incubation 63.9 +/- 3.7% (mean +/- SEM) of total LDH was released from B lung slices with 1.0 mg CYC/mL, whereas only 45.8 +/- 2.6% was released from C lung slices (P < 0.05). 3-AB reduced LDH release to 44.7 +/- 2.4% in B slices and 28.1 +/- 2.0% in C slices (P < 0.05 vs CYC only). PAP activity in nuclei isolated from CYC-treated B lung slices was increased 2- to 4-fold after 2 hr of incubation with 0.5 and 1.0 mg CYC/mL. PAP activation was delayed and reduced with incubation in 3-AB. PAP was activated 2-fold in nuclei from C slices treated with 0.5 mg CYC/mL for 2 hr. NAD was decreased at 2 and 4 hr in B slices treated with 0.5 and 1.0 mg CYC/mL, and at 4 hr with 0.1 mg CYC/mL. NAD depletion occurred only at 4 hr in the resistant C slices treated with 1.0 mg CYC/mL. CYC increased NADP by a similar extent in B and C lung slices. In B slices, NAD losses were approximately 4 times the increases in NADP. CYC did not decrease ATP in B slices and ATP dropped 25% only after 4 hr in the resistant C slices. We conclude that CYC is directly toxic to lung tissue and observe that strain sensitivity in vitro mirrors the sensitivity to fibrosis in vivo. PAP activation and oxidative stress may contribute to this toxicity.

Glutathione depletion in human erythrocytes as an indicator for microsomal activation of cyclophosphamide and 3-hydroxyacetanilide

A model system for the detection of reactive metabolites, using glutathione depletion after microsomal activation, has been described previously. We developed a battery of complementary test systems using rat liver microsomes for metabolism and aqueous glutathione solutions, human erythrocytes or hemolysate derived therefrom, as target. Reactive metabolite formation and the ability of metabolites to pass the erythrocyte membrane were tested using 3-hydroxyacetanilide (3-HAA) and cyclophosphamide (CP) as substrates. Neither unchanged 3-HAA nor CP depleted glutathione in erythrocytes or in aqueous reduced glutathione solutions (GSH solutions). Addition of fortified normal or liver microsomes from rats pretreated with phenobarbital (PB microsomes) induced a 3-HAA/CP concentration-dependent glutathione depletion in both systems. With PB microsomes, higher depletions were found. While unchanged 3-HAA did not deplete aqueous GSH solutions or glutathione in erythrocytes, a significant depletion in hemolysate was found. The results indicate that both CP and 3-HAA metabolites are able to pass through the erythrocyte membrane. While both substances can metabolically be activated by rat liver microsomes, only 3-HAA can be activated by soluble factors in erythrocytes. However, unchanged 3-HAA has no effect on GSH in erythrocytes. This might be caused by an inability of unchanged 3-HAA to enter the erythrocyte. More generally, an adequate combination of the test systems described can be used to detect (a) the reactivity of unchanged substances and their metabolites, and (b) the ability of unchanged substances and their reactive metabolites to pass through the erythrocyte membrane.

Antirheumatic drug reactions in the lung

Drug-induced lung disease during treatment with antirheumatic drugs should be considered in all patients receiving these agents who develop new pulmonary symptoms. When a potential drug-related reaction is identified, the possible offending agents should be discontinued, appropriate respiratory support initiated, and a thorough investigation for other causes of respiratory disease launched to exclude infection or other pulmonary processes. Lung biopsy may be needed to define the disorder completely. In patients with acute pneumonitis, the use of corticosteroids should be considered. Although significant morbidity and even mortality may occur with drug-induced pulmonary events, proper and prompt evaluation and treatment of these disorders can often result in complete resolution of the pulmonary disease.

Effects of cyclophosphamide and adriamycin on rat hepatic microsomal glucuronidation and lipid peroxidation

The effect of cytotoxic drug administration, as a single dose i.p. to rats (six rats/treatment group), on hepatic microsomal UDP-glucuronosyltransferase (UGT) activity was investigated. Glucuronidation of morphine in microsomes from control rats apparently involved at least two enzymes. Administration of cyclophosphamide (CP; 200 mg/kg 7 days prior to killing) significantly increased the rate of morphine glucuronidation over the range 0.05-10 mM, and significantly increased the apparent Vmax for the high capacity isoenzyme from 1.25 +/- 0.12 to 1.95 +/- 0.39 nmol/mg/min. In contrast, the activity of 1-naphthol UGT was not significantly altered by administration of CP. Rats treated with the same dose of CP 1 day prior to killing showed a significant decrease in microsomal morphine-UGT activity at 0.05 and 2.5 mM morphine, but a significant increase in activity was observed following administration of CP or Adriamycin (AD; 10 mg/kg) 4 days prior to killing. The extent of microsomal lipid peroxidation was significantly increased in microsomes obtained from rats treated with CP or AD 4 days prior to killing, and was positively correlated (P less than 0.001) with the rate of glucuronidation of 0.05 and 2.5 mM morphine. Preincubation of microsomes in the presence of CP (5 mM) and AD (100 microM) significantly decreased the rate of glucuronidation of 2.5 mM morphine. In vitro NADPH-mediated lipid peroxidation significantly increased the activity of both the high and low affinity morphine-UGT isoenzymes. Administration of the cytotoxic drugs CP and AD may alter microsomal morphine-UGT activity via the process of lipid peroxidation, although other mechanisms cannot be excluded.

[Vitamins during high dose chemo- and radiotherapy]

Plasma from 22 patients was examined for alpha- and gamma-tocopherol (vitamin E), the carotenoids beta-carotene (provitamin A) and lycopene, retinol (vitamin A), and ascorbic acid (vitamin C) before, during and after conditioning chemotherapy for bone marrow transplantation, 18 of these received total body irradiation as well. In addition, alpha-tocopherol in red blood cell membranes was measured. Retinol and ascorbic acid have been applied in multiple of the recommended doses (Deutsche Gesellschaft für Ernährung and Recommended Dietary Allowance, respectively). The chosen doses were sufficient to maintain the initial plasma concentrations of these vitamins. However, alpha-tocopherol (in RDA doses) and beta-carotene (no RDA established) concentrations deteriorated after the conditioning therapy (20 and 50% loss, respectively). The loss of these lipid-soluble antioxidants has been considered to result from lipid peroxidation. On the basis of the presented results we propose intervention studies to investigate the effect of high dose antioxidant administration on the toxicity (mainly of liver and lung) of intensive antineoplastic therapy protocols.

Pharmacokinetics, metabolic activation, and lung toxicity of cyclophosphamide in C57/B16 and ICR mice

A single intraperitoneal dose (200 mg/kg) of cyclophosphamide (CP) resulted in significantly less injury to the C57/B16 strain than to the ICR strain of mice. Maximal thymidine incorporation into total lung DNA, an indirect index of lung injury, and pulmonary hydroxyproline content, a marker of fibrosis, were 56 +/- 10% and 69 +/- 9 of ICR mice, respectively. Pharmacokinetics and metabolism of [side chain-3H]CP and [ring-14C]CP were assessed in vivo. In addition, covalent binding and the generation of polar metabolites were determined in hepatic and pulmonary microsomes from both strains. Peak levels and half-lives of radioactivity derived from CP in blood were similar in both strains treated with a 200 mg/kg dose. However, area under curve for total radioactivity over 12 hr was significantly lower (60 and 78% of ICR for 3H and 14C, respectively), and systemic clearance significantly higher (168 and 119% of ICR for 3H and 14C, respectively) in the C57 strain. Total radioactivity derived from CP in lung and liver was similar between strains at all time points examined up to 12 hr, but overall covalent binding of radioactivity, assessed as area under the binding curve, was markedly lower to C57 lungs in vivo (58 and 49% of ICR for 3H and 14C, respectively). In contrast, hepatic binding was not significantly different between strains with either label. No significant differences were evident between strains in hepatic or pulmonary microsomal binding in vitro. Polar CP metabolites in ICR lung were significantly higher than C57 at 2 hr in vivo, but no strain differences were evident at other times nor in the microsomal generation of polar metabolites. These results demonstrate significant differences in the pharmacokinetics of CP between C57 and ICR murine strains. NADPH-mediated activation of CP in vitro was similar between strains suggesting that the increased covalent binding of CP to ICR lung tissue in vivo was due to greater exposure to CP or its reactive metabolites. The relative resistance of C57 mice to CP-induced lung fibrosis may also be influenced by intrinsic differences in response of the lung to reactive CP species, or by differences in activation by other metabolic pathways.

Rate of increase of plasma drug level influences subjective response in humans

This study addressed the commonly held, but seldom tested, notion that faster rates of increase of drug effects are associated with more positive subjective effects. Sodium pentobarbital was administered to normal healthy volunteers in either a single oral dose or in a series of divided, cumulating doses, and subjective responses were monitored. Twelve subjects participated in three weekly sessions, during which they received capsules containing placebo, 150 mg pentobarbital in a single dose (SIN) or 180 mg pentobarbital administered in six divided doses (DIV) of 30 mg every 30 min. Doses of pentobarbital in the SIN and DIV were selected to produce similar peak plasma levels. Blood samples were obtained at regular intervals for plasma drug level determinations, and throughout the session subjects completed self-report mood questionnaires (e.g., Profile of Mood States, visual analog ratings of drug liking and drug "high") and psychomotor performance tests (e.g., Digit Symbol Substitution Test). As expected, the SIN and DIV conditions yielded similar peak levels of pentobarbital, but the peak was attained more rapidly in the SIN condition. Despite the similarity in peak plasma levels, subjects reached greater peaks in ratings of "high" and wanted more of the drug when they were in the SIN condition. On an end-of-session liking questionnaire they also reported significantly greater liking of the drug in the SIN condition. On other measures of drug effects (e.g., sedation and psychomotor impairment) no significant differences were observed between the conditions. Thus, the rate of increase of the drug's effects specifically influenced subjects' ratings on subjective measures (e.g., "high" and liking) that may be associated with risk for abuse.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclophosphamide toxicity. Characterising and avoiding the problem

Cyclophosphamide, an orally active alkylating agent, is widely used to treat a variety of malignant and nonmalignant disorders. Although it has some tumour selectivity, it also possesses a wide spectrum of toxicities. The requirement of metabolic activation before cyclophosphamide exerts either its therapeutic or toxic effects is well established, but has not led to effective counter-measures. Clinically, damage to the bladder (haemorrhagic cystitis), immunosuppression (when not desired) and alopecia are the most significant toxicities associated with cyclophosphamide. Cardiotoxicity is also a possibility when very high doses are given. Preventing these toxicities has focused on modifications of the treatment regimens and, in the case of haemorrhagic cystitis, the administration of a drug which is excreted in the urine where it inactivates the bladder-toxic species. As treatment regimens for cancer become more effective in prolonging a patient's life, and as cyclophosphamide receives increasing use for nonmalignant disorders, the potential for cyclophosphamide-induced cancers, particularly in the bladder, must be recognised. Although the toxicities associated with cyclophosphamide are serious, this agent remains a highly effective drug in many situations. Research on the pathways which play an important role in activating this drug may improve our ability to target particular diseases and decrease unwanted side effects.

Microcarrier-attached rat hepatocytes as a xenobiotic-metabolizing system in cocultures

A method for the primary culture of rat liver cells on collagen-coated dextran microcarriers is described. Ethoxycoumarin deethylase (EOD) activity 24 hr after inoculation was comparable for liver cells cultured on microcarriers and on collagen-coated dishes. Cells were cultured on microcarriers for up to 48 hr and retained 25% of the initial EOD-activity that was seen in freshly isolated liver cells. Microcarrier-attached hepatocytes were cocultured with BALB/c 3T3 cells to study the metabolism-mediated cytotoxicity of cyclophosphamide (CPA). In the absence of hepatocytes, growth of 3T3 cells was not affected by CPA at concentrations up to 3600 microM. In coculture with hepatocytes, cytotoxicity of CPA was expressed in a time- and concentration-dependent manner. At high concentrations, CPA slightly depressed the EOD-activity of hepatocytes. Our results indicate that cocultivation of microcarrier-attached rat liver cells with target cells represents a valuable approach to the study of the metabolism-mediated toxicity of xenobiotics in vitro.

Bioactivation of xenobiotics by prostaglandin H synthase

Prostaglandin H synthase (PHS) catalyzes the oxidation of arachidonic acid to prostaglandin H2 in reactions which utilize two activities, a cyclooxygenase and a peroxidase. These enzymatic activities generate enzyme- and substrate-derived free radical intermediates which can oxidize xenobiotics to biologically reactive intermediates. As a consequence, in the presence of arachidonic acid or a peroxide source, PHS can bioactivate many chemical carcinogens to their ultimate mutagenic and carcinogenic forms. In general, PHS-dependent bioactivation is most important in extrahepatic tissues with low monooxygenase activity such as the urinary bladder, renal medulla, skin and lung. Mutagenicity assays are useful in the detection of compounds which are converted to genotoxic metabolites during PHS oxidation. In addition, the oxidation of xenobiotics by PHS often form metabolites or adducts to cellular macromolecules which are specific for peroxidase- or peroxyl radical-dependent reactions. These specific metabolites and/or adducts have served as biological markers of xenobiotic bioactivation by PHS in certain tissues. Evidence is presented which supports a role for PHS in the bioactivation of several polycyclic aromatic hydrocarbons and aromatic amines, two classes of carcinogens which induce extrahepatic neoplasia. It should be emphasized that the toxicities induced by PHS-dependent bioactivation of xenobiotics are not limited to carcinogenicity. Examples are given which demonstrate a role for PHS in pulmonary toxicity, teratogenicity, nephrotoxicity and myelotoxicity.