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PubMed2003

Cyclophosphamide therapy for lupus nephritis: poor renal survival in Arab children.

Despite its widespread use, there are only a few published studies of the use of intravenous high-dose pulse cyclophosphamide in lupus nephritis in children. There are few data about the long-term efficacy and safety of this form of therapy. This study evaluates the clinical efficacy of this regimen in children with severe lupus nephritis followed prospectively over a 5-year period. Nine children with severe active lupus nephritis were enrolled in a treatment regimen of monthly intravenous pulses of cyclophosphamide (0.75-1 g/m(2)) for 6 months and then every 3 months for a total of 36 months. Cyclophosphamide treatment was associated with significant improvement in renal function during treatment. However, data presented here show that 56% of the patients progressed to chronic renal failure and 22% required dialysis 2 years after discontinuation of cyclophosphamide therapy. Hence it seems that this regimen is not effective in our patients in the long term, especially patients who present with high serum creatinine and hypertension.

Alkylating Agents↗

PubMed2006

Intensified, intermittent, low-dose intravenous cyclophosphamide together with oral alternate-day steroid therapy in lupus nephritis (long-term outcome).

The objective of this study is to evaluate the efficacy, toxicity, and long-term outcome of low-dose IV cyclophosphamid therapy with repeated frequent intervals in combination with oral and IV methylprednisolone in patients with SLE nephritis. In this study, 113 patients diagnosed as having SLE and glomerulonephritis were assessed in between 1993 and 2002, with a median follow-up of 44.1+/-41.2 months. The patients were treated with 500 mg IV cyclophosphamide and 1 g IV methylprednisolone together with 60 mg/alternate-day oral methylprednisolone in a given schedule. The clinical and laboratory data were evaluated. There were significant improvements in the clinical and the laboratory parameters. Six patients died shortly after being hospitalized due to the disease activity itself. Eight patients were excluded from the study because of low compliance. The renal functions of the patients remained stable throughout the therapy; only 16/99 patients needed one or two additional pulses. Temporary leukopenia developed in 18/99 patients and diminished with the suspension or prolongation of the IV cyclophosphamide administration. Gastrointestinal side effects, which needed extra medication, developed in 20 patients. Hematuria was observed in 6/99 patients. Menstrual abnormalities were seen in 7/99 patients. No serious infections due to immunosuppression were observed with the given regimen. Hypertension was observed in 13 patients (minimum of 140/90 mmHg, maximum of 190/110 mmHg) and controlled with angiotensine-converting enzyme inhibitors. Mild central obesity was observed in 15 of the patients. Leimyosarcoma was observed in one patient who died during the follow-up period. Therapy starting with the weekly low-dose IV cyclophosphamide to induce remission together with IV and oral steroids, followed by prolonged intervals with the same doses for 2 years, appears to be useful in preserving renal function without major side effects in patients with lupus nephritis, in comparison to other studies.

Administration, Oral↗

PubMed2005

Possible role of P-glycoprotein in cyclophosphamide resistance of transplanted mouse RLS lymphosarcoma.

The causes of different sensitivity of mouse LS lymphosarcoma and its resistant RLS variant to cyclophosphamide were studied. Division of LS and RLS cells stops in the G2/M phase 24 h after cyclophosphamide treatment, but this stop lasts for more than 48 h in LS cells and less than 24 h in RLS cells. DNA fragmentation, a marker of apoptosis, is observed only in LS cells starting from 24 h after cyclophosphamide treatment. LS and RLS strains do not differ by the expression of bcl-2, bcl-6, bax, bad, mdr1a, mdr1b genes and P-glycoprotein protein. The strains differ by transport activity of P-glycoprotein, tested by SYTO 16 substrate release from cells: activity of P-glycoprotein in RLS cells was 2-fold higher than in LS cells. Presumably, the resistance of RLS tumor to cyclophosphamide-induced apoptosis is a result of inhibition of the apoptotic cascade by P-glycoprotein which is functionally more active in these cells than in LS cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1983

Interactions between thyroxine, hydrocortisone and cyclophosphamide in their effects on the eruption of the rat mandibular incisor.

The effects on the unimpeded eruption rates of the rat mandibular incisor of daily doses of thyroxine (0.5 mg/kg) and hydrocortisone (12.5 mg/kg) and of a single injection of cyclophosphamide (40 mg/kg), either alone or in combination, were studied over approximately 15 days. Both the thyroxine and hydrocortisone alone produced increases in eruption, whereas a decrease was recorded with cyclophosphamide alone. When thyroxine was combined with hydrocortisone, the increase in eruption rate was greater than that with thyroxine or hydrocortisone alone. When cyclophosphamide was combined with hydrocortisone, there was no difference compared with cyclophosphamide alone. These results obtained with drug combinations are consistent with eruption having a multifactorial basis.

Animals↗

PubMed1988

The effect of corticosteroids and cyclophosphamide on the eruption of resected incisor teeth in the rat.

It has been observed that there may be two mechanisms making resected rat incisors erupt during their phase of normal eruption rates, only one of which works during their slow phase of eruption. The effects of cyclophosphamide and corticosteroids on the eruption of non-resected teeth may also be consistent with the presence of two eruptive mechanisms, one responsive to cyclophosphamide and corticosteroids, the other not, or less, responsive to them. To see whether this previous work has, in different experiments, revealed the same pair of mechanisms, the effects of cyclophosphamide and corticosteroids on resected incisors were investigated. Cortisone accelerated their eruption and cyclophosphamide slowed it when they were erupting at normal rates, but neither compound had any effect during the initial slow phase.

Animals↗

PubMed1977

The induction of sister chromatid exchanges by cyclophosphamide in the presence of differently induced microsomal fractions of rat liver.

The induction of sister chromatid exchanges can be monitored by a test that incorporates the factor of metabolic activation in a simple manner. The results with cyclophosphamide show that in this test the induction of the metabolizing enzymes of the rat liver homogenates used is very important. 3-Methylcholanthrene induces little if any extra conversion of cyclophosphamide to SCE-inducing metabolites, compared with no induction. Aroclor 1254 and phenobarbital however, were very good inducers. The difference found between the liver homogenates concerning SCE induction corresponded with the differences in cyclophosphamide metabolism, which was measured as the decrease in NADPH induced by cyclophosphamide.

Animals↗

PubMed1983

Embryopathic effects of cyclophosphamide.

Cyclosphosphamide, dissolved in saline, was injected into the air sac of white Leghorn chick eggs in dose levels of 0.005, 0.007, 0.010, 0.012, 0.015, and 0.017 mg per egg. Eggs received a single injection of cyclophosphamide on Days 0, 1, 2, or 3 of incubation. Control eggs were injected with an equivalent volume of saline (0.1 ml per egg). In all 904 chicken eggs were used for this study. Surviving embryos were sacrificed when they reached 11 days of incubation. The LD50 values for Days 1, 2, and 3 were 0.017, 0.007, and 0.012 mg per egg, respectively. The overall incidence of abnormal embryos for Days 0, 1, 2, and 3 were 7, 6.3, 12, and 22%, respectively. Abnormalities such as reduced body size, everted viscera, short and twisted limbs, eye defects, abnormal beak, and short and twisted neck were commonly seen in survivors no matter when exposed to cyclophosphamide. The teratogenicity of cyclophosphamide was noted to be the highest in the embryos treated on Day 3. The present study has demonstrated that cyclophosphamide is toxic and teratogenic during the period of early organogenesis in the chick embryos.

Abnormalities, Drug-Induced↗

PubMed1988

Development of porphyria cutanea tarda after treatment with cyclophosphamide.

Porphyria cutanea tarda, a metabolic disorder of heme biosynthesis, is characterized by cutaneous hyperpigmentation, facial hypertrichosis, dark urine, and a distinctive pattern of excess porphyrin production. Hepatic uroporphyrinogen decarboxylase activity is markedly reduced in patients with this disorder. Although porphyria cutanea tarda may be familial, it is more often sporadic in occurrence, and has been associated with excess alcohol ingestion, estrogen administration, iron overload, and several environmental hepatotoxins. It has also been associated on occasion with malignancy. We report a 46-yr-old woman with ovarian carcinoma who developed porphyria cutanea tarda while undergoing treatment with cisplatin and cyclophosphamide. The temporal course of the porphyrin abnormality suggested that cyclophosphamide was the pathogenic agent, and symptoms regressed after cessation of this drug with continued administration of cisplatin. The pathogenesis of the porphyria is not clear; however, cyclophosphamide is a substrate for cytochrome P450, and may produce metabolites that destroy this protein. The resulting increased turnover of heme might then result in overproduction of porphyrin precursors, resulting in the clinical syndrome. Studies of porphyrin metabolism in patients treated with cyclophosphamide may help to elucidate this possibility.

Cisplatin↗

PubMed1976

Genetic effects induced in Saccharomyces cerevisiae by cyclophosphamide in vitro without liver enzyme preparations.

Cyclophosphamide induced forward mutation in Saccharomyces cerevisiae strain S288C and mitotic recombination in strains D3 and D5 but not in strain D4. The yeast cells were treated with the compound in phosphate buffer without recourse to metabolic activation protocols. Elevation of the treatment temperature increased the genetic activity of cyclophosphamide. Respiration-deficient isolates of strains S288C and D3 were more sensitive than the respiratory competent parent strains were for inducing forward mutation and mitotic recombination, respectively. Cyclophosphamide was incubated in phosphate buffer alone for increasing time intervals; strain D3 cells were added to aliquots for each time interval and incubated for an additional 30 min. The frequency of induced recombination increased as the time of compound incubation increased, showing that spontaneous degradation of cyclophosphamide to genetically active breakdown products was responsible for the genetic damage induced in the yeast cells.

Cyclophosphamide↗

PubMed1984

Morphological and cytogenetic studies of dominant lethality induced by mitomycin C and cyclophosphamide in female germ cells. The use of Robertsonian translocations as a 'marker system' to identify the zygote pronuclei.

Dominant lethal tests were performed on female mice injected intraperitoneally with cyclophosphamide (200 mg/kg) or with mitomycin C (0.2 or 5 mg/kg) at the preovulatory stage of oogenesis. Complementary experiments were undertaken to clarify the results obtained. Embryo culture showed that sterility found after treatment with cyclophosphamide or with the high dose of mitomycin C was the reflection of true dominant lethal effects. Mortality after cyclophosphamide treatment occurred predominantly at the 2- and 3-cell stages, while it was reported in all preimplantation stages after treatment with the high dose of mitomycin C. Embryos treated with the low dose of mitomycin C developed normally to the blastocyst stage, confirming the absence of preimplantation effects found with this dose in the dominant lethal test. Cytogenetic analysis of female pronuclei at the first cleavage division were performed after mating treated females with males homozygous for one Robertsonian translocation. This method allowed one to distinguish easily the female pronuclei from the male ones, which exhibited one translocated 'marker' chromosome. After treatment with cyclophosphamide, most female pronuclei showed multiple chromatid exchanges or shattering of the entire genome. After treatment with the high dose of mitomycin C, various types of premature chromosome condensation were found, and they were often accompanied by important interchromosome associations. After treatment with the low dose of mitomycin C, no structural chromosome aberrations were found, and the number of numerical anomalies was not significantly different from that found in control embryos. These last results suggest that the increase in rate of postimplantation loss obtained in the dominant lethal test with the low dose of mitomycin C was not due to clastogenic effects of this compound in the female germ cells, but rather to indirect effects on the maternal organism.

Animals↗

PubMed1987

Pyridine prevents the clastogenicity of benzene but not of benzo[a]pyrene or cyclophosphamide.

Pyridine has been shown to be a much more potent inhibitor than other solvents of the metabolism and therefore the clastogenicity of benzene. In this report, pyridine prevented benzene-derived micronucleus formation in the bone marrow of ICR Swiss mice at much lower levels than xylene did. Time-course experiments did not indicate any delay in the peak micronucleus response to benzene caused by either pyridine or xylene. Similar experiments using pyridine with benzo[a]pyrene and pyridine with cyclophosphamide indicated that the effect of pyridine was specific for benzene. Benzo[a]pyrene (150 mg/kg) was inhibited by pyridine only at levels of 100 mg/kg or more, compared to inhibition of benzene (440 or 880 mg/kg) by pyridine at levels of 5 mg/kg. Cyclophosphamide was not inhibited at any level, and micronucleus formation was increased at lower ratios of pyridine to cyclophosphamide. These results provide indirect conformation of the work by others indicating that benzene is activated in part by a cytochrome P450 isozyme different from those activating benzo[a] pyrene or cyclophosphamide. Since DBA/2 mice (AHH-non-inducible) are more sensitive to benzene than C57Bl/6 mice (AHH-inducible), single and multiple treatments with benzene were compared by micronucleus response in these two strains. DBA mice were more responsive in all cases. Pretreatment with methylcholanthrene caused a greater response to benzene in DBA/2 mice, suggesting that the cytochrome P450 isozyme involved is one of the forms induced by methylcholanthrene independent of the high-affinity Ah receptor. It is hypothesized that more efficient activation of benzene by the unique cytochrome P450 isozyme, perhaps combined with relatively less conjugation, may result in a greater sensitivity of the bone marrow versus the liver, and of DBA/2 versus C57Bl/6 mice.

Animals↗

PubMed1992

Influence of denervation on smooth muscle response to repeated administration of cyclophosphamide, cytosine arabinoside, or their combination.

Cyclophosphamide, 40 mg.kg-1, cytosine arabinoside, 2 mg.kg-1 or their combination, were all given once weekly to chicks for 5 weeks. The expansor secundariorum muscle of the left wing of each chick was then surgically denervated leaving that of the right wing to serve as the control. Drug administrations continued for a further 5 weeks before the responses of normal and denervated expansor muscles were determined pharmacologically. Cyclophosphamide depressed the response of the expansor muscle to noradrenergic nerve stimulation but enhanced the response to noradrenaline and potassium chloride. Cytosine arabinoside enhanced responses of expansor muscles to noradrenergic nerve stimulation and noradrenaline, but depressed responses evoked by potassium chloride. The combination enhanced responses to nerve stimulation, noradrenaline, and potassium chloride. Expansor muscles were unresponsive to acetylcholine and anticancer drugs failed to restore the responsiveness to acetylcholine except the combination. Denervation depressed responses to noradrenergic nerve stimulation but caused supersensitivity to noradrenaline; this was more marked in the combination and cyclophosphamide groups, with no change in sensitivity seen in the cytosine arabinoside group. The denervated expansor muscle responded to acetylcholine in the order, combination much greater than cyclophosphamide greater than control greater than cytosine group. Denervated expansor muscles from anticancer groups were supersensitive to potassium chloride, with the combination group having the most pronounced effect. It is suggested that denervation influences smooth muscle sensitivity to agonist drugs which can modify the effects of anticancer drugs on smooth muscle.

Adrenergic Fibers↗

PubMed1983

Contrasting effects of cyclophosphamide and prednisolone on the phenotype of human peripheral blood leukocytes.

The cell surface phenotype of human peripheral blood mononuclear cells has been characterized before and after intravenous injection of cyclophosphamide or prednisolone. Low doses of cyclophosphamide (100-600 mg/m2) temporarily decrease levels of circulating B lymphocytes. Slightly higher doses of cyclophosphamide (200-600 mg/m2) produce transient depression of T8-, M1-, and Ia-positive cells. After doses of 200-400 mg cyclophosphamide/m2, T4-positive cells are spared, resulting in a transient elevation of the T4/T8 ratio. With higher doses of cyclophosphamide (greater than or equal to 600 mg/m2), all T cells are affected and the T4/T8 ratio declines to pretreatment levels. By contrast, intravenous injection of prednisolone at 40 mg/m2 reduces the T4/T8 ratio. Levels of both T4 and T8 cells decline, but T4 cells are affected more markedly than T8 cells.

Adult↗

PubMed1984

Cyclophosphamide-induced changes in the MRL-lpr/lpr mouse: effects upon cellular composition, immune function, and disease.

MRL-lpr/lpr mice develop massive lymphadenopathy with excessive proliferation of T cells and associated immune abnormalities. To examine whether to not the disease process is intrinsic and irreversible, an immunomodulatory drug, cyclophosphamide, was administered to 16-week-old, sick MRL-lpr/lpr mice. Analysis of lymph node cells by flow cytometry from injected and control MRL-lpr/lpr mice indicated that cyclophosphamide had a marked effect upon the lymphoid cellular composition. Whereas control lymph nodes had a very large number of abnormal dull Ly 1+ T cells and very few other cells, the cyclophosphamide-injected mice had normal T and B cells. The immune responses to a T-cell-dependent antigen, sheep red blood cells, and a T-cell mitogen, concanavalin A, were normalized in cyclophosphamide-injected mice as compared to controls. In addition, injected mice had prolonged survival, decreased arthritis, markedly reduced adenopathy and splenomegaly, improved renal histology, and significantly diminished autoantibody levels. This study suggests that the disease and associated immune abnormalities of MRL-lpr/lpr mice are reversible by selective elimination of the abnormal dull Ly 1+ T cells.

Animals↗

PubMed1985

Hypersensitivity reaction to a metabolite of cyclophosphamide.

Generalized urticaria and fever were noted in a patient with IgA (kappa) myeloma after intravenous cyclophosphamide. Intradermal skin testing revealed no reaction to cyclophosphamide and its analog, isophosphamide. However, phosphoramide mustard, a principle metabolite of cyclophosphamide, evoked an immediate wheal-and-flare response. Subsequent therapy with isophosphamide was well tolerated. These findings suggest that acute hypersensitivity reactions to cyclophosphamide are due to its metabolites and can be delineated with skin testing.

Cyclophosphamide↗

PubMed1986

Intradermal administration of 4-hydroperoxy-cyclophosphamide during contact sensitization potentiates effector T cell responsiveness in draining lymph nodes.

4-Hydroperoxy-cyclophosphamide (4-HPCY) is an in vitro active form of cyclophosphamide. In a previous study, using an in vivo contact sensitivity model in the guinea pig, we demonstrated that intradermal injection of small amounts (50-200 micrograms) of 4-HPCY at the sensitization site resulted in strong potentiation of contact hypersensitivity (Boerrigter and Scheper, 1984). It was postulated that 4-HPCY induces a local decrease of feedback control within the draining antigenically stimulated lymph nodes. The present data are in support of this view: Lymph node hyperplasia induced by contact sensitization (to dinitrochlorobenzene or oxazolone) was further enhanced by 4-HPCY treatment. The paracortical area was preferentially enlarged. 4-HPCY-treated lymph nodes showed an augmentation of hapten-specific T effector cell function as determined in transfer experiments. The response of such lymph node-derived cells to the T cell mitogen PHA was enhanced. Although 4-HPCY treatment resulted simultaneously in a decrease in responsiveness of draining lymph node-derived cells to the B cell mitogen lipopolysaccharide, anti-hapten antibody production was not affected. The present study demonstrates that important similarities exist between the effects of local 4-HPCY treatment and systemic cyclophosphamide pretreatment on the immune response. As systemic treatment with a high dose of cyclophosphamide is known to have serious side effects, the present local protocol provides a new attractive and versatile strategy for T cell immunopotentiation.

Animals↗

PubMed1985

The effects of age, sex and diet on the clastogenic action of cyclophosphamide in mouse bone marrow.

7-week-old and 12-week-old mice of both sexes received either a control or protein-deficient diet for 3 weeks. Afterwards, they were given a single dose of cyclophosphamide (0.5 mg/10 g b.wt.) before being sacrificed. The relationship between age and the clastogenic action of cyclophosphamide can be observed in the bone marrow cells of male mice but not in those of female mice. 12-week-old males on a 75% protein-deficient diet have a lower frequency of cells with cyclophosphamide-induced chromosome aberrations than has the control group. On the contrary, 7-week-old males and females, and 12-week-old females, show that protein-deficient diets act synergistically with the clastogenic action of cyclophosphamide. These results are discussed taking the metabolism of the drug into account. Animal age also plays a role in the formation of chromosome rearrangements; this type of aberration is significantly more frequent in younger animals of both sexes than in older ones exposed to the drug.

Age Factors↗

PubMed1988

In vivo and in vivo/in vitro kinetics of cyclophosphamide-induced sister-chromatid exchanges in mouse bone marrow and spleen cells.

In several acute and chronic exposures to various chemicals in vivo and in vitro, the average sister-chromatid exchange (SCE) frequencies in human, mouse, rat, and rabbit lymphocytes generally decrease with time following treatment. The rate of this decline varies, but little data have been published pertaining to the comparative kinetics of SCEs both in vivo and in vivo/in vitro (exposure of animals to the test compound and culturing of cells) simultaneously in the same tissues. In this study, a single dose of cyclophosphamide (40 mg/kg) was injected for varying periods (6-48 h) and its effects, as assessed by the induction of SCEs, were analyzed under both in vivo and in vivo/in vitro conditions in mouse bone marrow and spleen cells. In vivo, the cyclophosphamide-induced SCEs increased with increasing time up to 12 h, stayed at approximately the same level until 24 h, and then decreased with increase in post-exposure time. However, the SCE levels remained significantly higher than controls at 48 h post-exposure time in both bone marrow and spleen cells. Under in vivo/in vitro conditions, the SCEs in bone marrow decreased with increase in post-exposure time until reaching control values by 48 h post exposure. However, in spleen cells, the decrease in SCE level was gradual, and by 48 h post-exposure time, the cells still had approximately 6 times higher SCEs than the control values. These results suggest that there are pharmacokinetic differences for cyclophosphamide in mouse bone marrow and spleen. Also, there is a differential SCE response to cyclophosphamide under in vivo and in vivo/in vitro conditions.

Animals↗