Adriamycin causes hyperlipemia as a consequence of nephrotoxicity

Artemisia capillaris Thunb. water extract attenuates adriamycin-induced renal injury by regulating apoptosis through the ROS/MAPK axis

Artemisia capillaris Thunb. is widely used in the treatment of kidney diseases, but the underlying mechanism remain elusive. Therefore, this study aimed to elucidate the mechanism of Artemisia capillaris Thunb. in alleviating renal injury. And renoprotective effects of freeze-dried powder of Artemisia capillaris Thunb. water extract (WAC) were assessed using adriamycin (ADR)-induced renal injury to the NRK-52E cells and ADR-induced renal injury Sprague-Dawley rats (SD rats) models. The results show that WAC could alleviate ADR-induced renal injury in SD rats and the NRK-52E cell line, improved renal function (BUN 9.73 ± 0.35 vs 7.13 ± 0.15, SCR 80.60 ± 1.68 vs 60.50 ± 1.42, ACR 11.50 ± 0.50 vs 8.526 ± 0.15) or cell viability (IC₅₀ = 1.08 µg/ml (ADR), cell viability increase 36.38% ± 6.74% (added 4 mg/ml WAC)), and reduced the apoptosis. Moreover, WAC inhibited the MAPK signal transduction, increased the expression of superoxide dismutase 1 (SOD1), and decreased the production of ROS. The treatment of N-acetylcysteine (NAC, antioxidant) in vitro showed that NAC inhibited apoptosis and alleviated renal injury by inhibiting oxidative stress and reducing the phosphorylation of proteins related to the MAPK signaling pathway. Therefore, these results suggested that WAC can alleviate ADR-induced renal injury and apoptosis by regulating the ROS/MAPK axis and has potential to be used as a renoprotective drug. PRACTICAL APPLICATIONS: Artemisia capillaris Thunb., which is a medicinal and edible plant, is widely used to treat kidney diseases in traditional Chinese medicine. The present research examined the renal protective effect of Artemisia capillaris Thunb. The results show that Artemisia capillaris Thunb. can effectively reduce renal tubular cell apoptosis through the ROS/MAPK axis in vivo and in vitro. In general, Artemisia capillaris Thunb. can be used as a potential herb to attenuate renal injury and further research can be conducted to explore its renoprotective mechanisms.

A scrutiny of circulating microRNA biomarkers for drug-induced tubular and glomerular injury in rats

Drug-induced acute kidney injury (AKI) is a frequent cause of adverse drug reaction. Serum creatinine (CRE) and blood urea nitrogen (BUN) are widely used as standard biomarkers for kidney injury; however, the sensitivity and specificity are considered to be low. In recent years, circulating microRNA (miRNAs) have been attracting considerable attention as novel biomarkers for organ injury, but there are currently no established miRNA biomarkers for drug-induced AKI. The present study aimed to identify plasma miRNAs that may enable early and specific detection of drug-induced tubular and glomerular injury through next-generation sequencing analysis. Six-week old male Sprague-Dawley (SD) rats were intravenously administered cisplatin (CSP, 6 mg/kg) and gentamicin (GEN, 120 mg/kg) to induce tubular injury. To create glomerular injury models, puromycin (PUR, 120 mg/kg) and doxorubicin (DOX, 7.5 mg/kg) were intravenously administered, and these models were always accompanied by tubular damage. Small RNA-sequencing was performed to analyze time-dependent changes in the plasma miRNA profiles. The cluster analyses showed that there were distinct plasma miRNA profiles according to the types of injury, and the changes reflected the progress of renal damages. In the differential analysis, miR-3473 was specifically up-regulated in the glomerular injury models. miR-143-3p and miR-122-5p were commonly down-regulated in all models, and the changes were earlier than the traditional biomarkers, such as plasma CRE and BUN. These data indicated that changes in the specific miRNAs in plasma may enable the early and sensitive detection of tubular and glomerular injuries. The present study suggests the potential utility of plasma miRNAs in the early and type-specific detection of drug-induced AKI.

Comparison of Cardiac Troponin I and T, Including the Evaluation of an Ultrasensitive Assay, as Indicators of Doxorubicin-induced Cardiotoxicity

Cardiac troponin (cTn) has been utilized to assess acute myocardial injury, but the cTn response in active/ongoing chronic injury is not well documented. The purpose of this study was to characterize the cardiac troponin I (cTnI), cardiac troponin T (cTnT), high-sensitivity cTnI, hematology, and clinical chemistry responses in rats treated with doxorubicin. Rats treated with 1, 2, or 3 mg/kg/week (wk) of doxorubicin for 2, 4, or 6 wks were sacrificed after 0, 2, or 4 wks of recovery and compared to untreated controls and animals treated with doxorubicin/dexrazoxane (50 mg/kg/wk) or etoposide (1 and 3 mg/kg/wk). The incidence and mean magnitude of cTn response increased with increasing dose and/or duration of doxorubicin treatment. Conversely, dexrazoxane/doxorubicin was partially protective for cardiotoxicity, and minimal cardiotoxicity occurred with etoposide treatment. Both cTnI and cTnT effectively identified doxorubicin-induced injury as indicated by vacuolation of cardiomyocytes of the atria/ventricles. The association between the cTn responses and histological changes was greater at the higher total exposures, but the magnitude of cTn response did not match closely with histologic grade. The high-sensitivity cTnI assay was also effective in identifying cardiac injury. Alterations occurred in the hematology and clinical chemistry parameters and reflected both dose and duration of doxorubicin treatment.

Characteristics of genomic signatures derived using univariate methods and mechanistically anchored functional descriptors for predicting drug- and xenobiotic-induced nephrotoxicity

ABSTRACT The ideal toxicity biomarker is composed of the properties of prediction (is detected prior to traditional pathological signs of injury), accuracy (high sensitivity and specificity), and mechanistic relationships to the endpoint measured (biological relevance). Gene expression-based toxicity biomarkers ("signatures") have shown good predictive power and accuracy, but are difficult to interpret biologically. We have compared different statistical methods of feature selection with knowledge-based approaches, using GeneGo's database of canonical pathway maps, to generate gene sets for the classification of renal tubule toxicity. The gene set selection algorithms include four univariate analyses: t-statistics, fold-change, B-statistics, and RankProd, and their combination and overlap for the identification of differentially expressed probes. Enrichment analysis following the results of the four univariate analyses, Hotelling T-square test, and, finally out-of-bag selection, a variant of cross-validation, were used to identify canonical pathway maps-sets of genes coordinately involved in key biological processes-with classification power. Differentially expressed genes identified by the different statistical univariate analyses all generated reasonably performing classifiers of tubule toxicity. Maps identified by enrichment analysis or Hotelling T-square had lower classification power, but highlighted perturbed lipid homeostasis as a common discriminator of nephrotoxic treatments. The out-of-bag method yielded the best functionally integrated classifier. The map "ephrins signaling" performed comparably to a classifier derived using sparse linear programming, a machine learning algorithm, and represents a signaling network specifically involved in renal tubule development and integrity. Such functional descriptors of toxicity promise to better integrate predictive toxicogenomics with mechanistic analysis, facilitating the interpretation and risk assessment of predictive genomic investigations.

RETRACTED: Rosiglitazone and pioglitazone aggravate doxorubicin-induced cardiomyopathy in Wistar rats

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.biomag.2010.12.001 The duplicate article has therefore been withdrawn.

Role of carnitine in cancer chemotherapy-induced multiple organ toxicity

In the last few years, cancer chemotherapy has been successfully employed in the treatment of different types of human tumours. Unfortunately, the optimal clinical usefulness of this important treatment modality is usually limited secondary to the development of life-threatening multiple organ toxicity. Cancer chemotherapy may cause these toxic effects by mechanisms not involved in their anticancer activity that can severely affect the life of patients and represent a direct cause of death. Several experimental and clinical studies have demonstrated that some important anticancer drugs interfere with the absorption, synthesis, and excretion of carnitine in non-tumour tissues, resulting in a secondary carnitine deficiency which is reversed by carnitine treatment without affecting anticancer therapeutic efficacy. Prototypes of anticancer drugs that alter carnitine system are doxorubicin, cisplatin, carboplatin, oxaliplatin, cyclophosphamide and ifosfamide. Furthermore, cachectic cancer patients are especially at risk for carnitine deficiency due to decreased oral intake and/or increased renal losses. Altered serum and urine carnitine levels have been reported in cancer patients with various forms of malignant diseases. Recent studies in our laboratory have demonstrated that carnitine deficiency constitute a risk factor and should be viewed as a mechanism during development of oxazaphosphorines-induced cardiotoxicity in rats. Similarly, inhibition of gene expression of heart fatty acid-binding protein and organic cation/carnitine transporter in doxorubicin cardiomyopathic rat model has been reported. In view of these facts and in view of irreplaceability of these important anticancer drugs, this review aimed to highlight the role of carnitine depletion and supplementation during development of chemotherapy-induced multiple organ toxicity.

A metabonomic study on the biochemical effects of doxorubicin in rats using (1)H-NMR spectroscopy

Metabonomic investigation of doxorubicin (adriamycin) was carried out in male Sprague-Dawley rats using high-resolution (1)H nuclear magnetic resonance (NMR) spectroscopy coupled with multivariate statistics. Urine samples (d -1 to 7) from rats treated with doxorubicin at two dose levels (5 or 15 mg/kg body weight) were collected at each time point and doxorubicin-induced biomarkers were examined. Of metabolites, early elevated biochemical changes were observed in trimethylamine N-oxide (TMAO) levels suggesting renal dysfunction. Perturbation in TMAO was maximal in the low-dose group at 48 h post dose (p.d.) and returned to control at 168 h p.d., indicating recovery from renal toxicity induced by doxorubicin. After doxorubicin administration, the high-dose group was divided into low and high responders at 48 h and further divided into high, moderate, and no recovery animals at 96 h, indicating individual susceptible response to drug-induced toxicity. Urinary increases in glucose, lactate, alanine, and valine suggested progression of renal damage resulting in glycosuria, lactic aciduria, and aminoaciduria up to 168 h in the high-dose group. Urinary elevation of creatine and phenylacetylglycine (PAG) together with reduction of N-methylnicotinic acid (NMNA) and hippurate levels was suggestive of liver injury in the high-dose group. Impairment of energy metabolism was also indicated by decreased levels of tricarboxylic acid cycle intermediates in urine of rats treated with high-dose doxorubicin. This study highlights the applicability of NMR-based metabonomics with multivariate statistics for monitoring biomarkers produced by doxorubicin treatments.

Distribution of anticancer antibiotic daunomycin in the rat heart and kidney revealed by immunocytochemistry using monoclonal antibodies

Two monoclonal antibodies (ADM-1-11 and 79-31 mAbs) were raised against daunomycin (DM) conjugated to bovine serum albumin via the cross-linker N-(gamma-maleimidobutyryloxy)succinimide. The monoclonal antibodies (mAbs) specifically detected DM as well as its analogs doxorubicin and epirubicin, but did not react with other anticancer antibiotics, including pepleomycin, mitomycin C, and actinomycin D. The mAbs reacted strongly with glutaraldehyde-conjugated DM in an enzyme linked immunosorbent assay (ELISA) used as a model system for immunocytochemistry as well as in appropriately pretreated sections of tissues from animals injected with DM. No staining occurred in tissues from uninjected animals. In order to perform DM ICC a number of tissue treatment conditions critical to the detection of low molecular weight substances were employed. Uptake of DM was studied in rats after a single i.v. or i.p. administration of the drug. In the heart, accumulation of DM occurred in nuclei and in the cytoplasm. In the kidney, DM immunoreactivity accumulated in all segments of the nephron except for the proximal tubules. Since the proximal tubules are known to be where a variety of transport systems including P-glycoprotein (Pgp) and organic anion-transporting polypeptides (OATPs) in drug interactions occur, the absence of DM accumulation in these segments may reflect a transport phenomenon depending upon such transporters. The availability of methods to study sites of accumulation of DM offers possibilities for understanding toxic side effects of this drug on the heart and kidney. Moreover, the immunocytochemical methodology developed may prove useful for the localization of other low molecular weight drugs that can be fixed in situ by glutaraldehyde.

Beneficial cardio-renovascular effects of a low-molecular-weight heparin-derivative on adriamycin-induced glycosaminoglycanuria and tissue lipid abnormalities

The present work includes a study on the glycosaminoglycanuric condition induced by adriamycin (ADR, a chemotherapeutic agent) and the accompanying secondary hyperlipidemia, wherein the treatment with a low-molecular-weight heparin-derivative (LMWH), certoparin, is evaluated for its protective role (if any) on these parameters. Two groups of male albino rats of the Wistar strain (140+/-10 g) received a single intravenous injection of adriamycin (7.5 mg/kg), and one of these groups was treated with a low-molecular-weight heparin-derivative (Certoparin Sodium, Troparin; 300 microg/day/rat s.c.), commencing on day 8, for a week. Urinary total glycosaminoglycans excretion of the untreated ADR-induced group was found to increase on the 8th and the 15th days of observation, when compared with the controls. The LMWH treatment commencing on day 8 resulted in minimising the glycosaminoglycans (GAGs) excretion by day 15 (p<0.001). Plasma, cardiac, hepatic and renal lipids (cholesterol, triglycerides and phospholipids) showed a sharp increase in the pathologic group, along with a rise in plasma LDL and VLDL cholesterol and drop in HDL cholesterol levels, paralleled by abnormal activities of the enzymes involved in lipid metabolism. LMWH treated group showed a normalised lipid profile and the activities of the lipid-metabolising enzymes was close to that of controls. It is concluded herein that adriamycin administration resulted in severe nephropathy manifested by increased glycosaminoglycanuria and abnormal lipid metabolism, and that LMWH treatment afforded substantial protection by restoring glomerular structure and function, and normalised the plasma and tissue lipid levels, lipoprotein profile and the activities of lipid-metabolising enzymes.

Comparative study of chronic toxic effects of daunorubicin and doxorubicin in rabbits

This study compares the chronic toxicity of two anthracyclines--daunorubicin and doxorubicin, commonly used for induction of anthracycline cardiomyopathy in the rabbit model. Such a comparative study has not been published until now. Both drugs were administered intravenously to male Chinchilla rabbits in doses at 3 mg/kg (50 mg/m2) once weekly for 10 weeks. Selected biochemical, haematological and cardiovascular parameters and body weights were regularly monitored; additionally, a histological evaluation of heart, kidney and liver was performed at the end of the experiment. In the daunorubicin group, there were marked signs of the progressive development of heart failure, like the significant increases of the pre-ejection period/left ventricular ejection time index values (up to 134%)--and histological changes within the myocardium were also observed. On the other hand, the 10-week doxorubicin administration did not cause these changes that are typical for heart injury. Haematotoxicity, manifested particularly by aplastic anaemia, was apparent in both the experimental groups. Significant body weight loss (by 45.2%) and high premature mortality (100% versus 36.4%) reflected a greater general toxicity, especially nephrotoxicity of doxorubicin in comparison with daunorubicin. Further studies are necessary to find a possible explanation for these findings.

Renal antioxidant enzymes and fibrosis-related markers in the rat adriamycin model

Excessive generation of reactive oxygen intermediates can induce changes in the cellular antioxidant defence system. In this study we examine the antioxidant enzyme status and the expression of fibrosis-related marker proteins in the Adriamycin model of chronic renal failure in the rat. Twenty weeks after Adriamycin treatment, rats have overt nephrotic syndrome and renal failure with development of tubulo-interstitial fibrosis and glomerulosclerosis. Lipids accumulate in blood and in both glomeruli and tubulo-interstitial tissue. Desmin and alpha-smooth muscle actin expression increases in glomeruli and in the tubulo-interstitial area. Renal cortex antioxidant enzyme activities are decreased 20 weeks after Adriamycin injection (to 41% for catalase, to 56% for total superoxide dismutase and to 69% for glutathione peroxidase). The mRNA levels of catalase, Cu/Zn-superoxide dismutase and glutathione peroxidase-1 evaluated by Northern blot are decreased by more than 50% for catalase, Cu/Zn-superoxide dismutase and glutathione peroxidase-1. We conclude that in the rat Adriamycin-induced model of chronic renal failure with fibrosis, the combination of decreased antioxidant enzyme status in renal cortex with high concentrations of lipids in blood and renal tissue facilitates oxidative damage. Development of fibrosis is paralleled by increased expression of desmin and alpha-smooth muscle actin.

Cancer and anticancer therapy-induced modifications on metabolism mediated by carnitine system

An efficient regulation of fuel metabolism in response to internal and environmental stimuli is a vital task that requires an intact carnitine system. The carnitine system, comprehensive of carnitine, its derivatives, and proteins involved in its transformation and transport, is indispensable for glucose and lipid metabolism in cells. Two major functions have been identified for the carnitine system: (1) to facilitate entry of long-chain fatty acids into mitochondria for their utilization in energy-generating processes; (2) to facilitate removal from mitochondria of short-chain and medium-chain fatty acids that accumulate as a result of normal and abnormal metabolism. In cancer patients, abnormalities of tumor tissue as well as nontumor tissue metabolism have been observed. Such abnormalities are supposed to contribute to deterioration of clinical status of patients, or might induce cancerogenesis by themselves. The carnitine system appears abnormally expressed both in tumor tissue, in such a way as to greatly reduce fatty acid beta-oxidation, and in nontumor tissue. In this view, the study of the carnitine system represents a tool to understand the molecular basis underlying the metabolism in normal and cancer cells. Some important anticancer drugs contribute to dysfunction of the carnitine system in nontumor tissues, which is reversed by carnitine treatment, without affecting anticancer therapeutic efficacy. In conclusion, a more complex approach to mechanisms that underlie tumor growth, which takes into account the altered metabolic pathways in cancer disease, could represent a challenge for the future of cancer research.

Enhanced hexachloro-1:3-butadiene nephrotoxicity in rats with a preexisting adriamycin-induced nephrotic syndrome

Renal damage was assessed by histopathology and urinalysis in male Wistar rats treated with either hexachloro-1:3-butadiene (HCBD; a single 170-mg/kg ip dose that caused proximal tubule necrosis), adriamycin (ADR; a single 5-mg/kg ip dose that caused minimal glomerular changes up to 35 days), or HCBD given 2 wk after ADR and compared with age-matched control rats for 21 days. Urinalysis values in ADR-treated rats showed minimal renal changes. HCBD significantly elevated urine volume (10-fold), protein (5-fold), glucose (175-fold), and brush border enzymes (10-600-fold), indicating severe proximal tubular damage, but most parameters returned to pretreatment levels 6 days after treatment. In ADR-pretreated rats subsequently given HCBD, both the urinary alkaline phosphatase and the ratio of kidney: body weight were significantly higher for longer periods. Histopathology demonstrated that the HCBD-induced proximal tubular lesion was confined to the outer stripe of the outer medulla. Advanced regeneration and repair was evident 21 days after HCBD treatment. In the ADR-pretreated rats the HCBD-induced lesion was more severe and affected the entire cortex and was characterized by marked tubular epithelial calcification, with little evidence of repair and tubular restitution 21 days after treatment. Enzyme histochemistry showed gamma-glutamyltranspeptidase localized to the proximal tubules. After HCBD treatment the enzyme staining was lost and subsequently returned in parallel with histological recovery up to 21 days. The distribution and intensity of gamma-glutamyltranspeptidase was unchanged in ADR-treated rats. The distribution and intensity of gamma-glutamyltranspeptidase in kidneys of ADR-pretreated rats given HCBD had not returned to normal by day 21. The results of this study indicate that pretreatment with ADR increases HCBD-induced nephrotoxic damage and decreases renal cortical repair capacity.

Effects of chronic administration of doxorubicin on myocardial creatine phosphokinase and antioxidant defenses and levels of lipid peroxidation in tissues and plasma of rats

Tissue and plasma levels of thiobarbituric acid reactive substances (TBARS) were measured in rats treated chronically with doxorubicin. In addition, heart creatine phosphokinase and antioxidant defenses were examined. Male rats received doxorubicin (DXR) 2 mg/kg or vehicle weekly subcutaneously for 13 weeks and were sacrificed at 14 and 19 weeks, 1 and 6 weeks after the last dose, respectively. Histological evaluation in DXR-treated rats at 14 and 19 weeks found significant and progressive cardiac and renal lesions as compared to controls. Heart TBARS were unchanged from controls. Plasma and kidney levels of TBARS were elevated above controls at both 14 and 19 weeks. Lung levels of TBARS were significantly elevated above controls at 14 weeks. Liver levels of TBARS were elevated at 19 weeks. Heart creatine phosphokinase activity was significantly depressed from controls at both 14 and 19 weeks. Heart glutathione peroxidase and superoxide dismutase activities were unchanged from controls. Heart glutathione, glutathione reductase, glucose-6-phosphate dehydrogenase, and catalase were elevated above controls at both 14 and 19 weeks. The lack of change in heart TBARS suggests that changes in TBARS in other organs may be secondary processes. The depression of creatine phosphokinase suggests that levels of adenosine triphosphate may be insufficient to sustain the myocardial function and this may partly be responsible for DXR-induced cardiac myopathy.

The effect of chronic adriamycin treatment on heart kidney and liver tissue of male and female rat

The influence of chronic adriamycin treatment on cellular defence mechanisms against free radicals has been determined in rats. To that end, the changes in vitamin E content, activity of superoxide dismutase, catalase and factors of the glutathione system were measured in heart, kidneys and liver after 24 and 52 days of treatment. Moreover, damage was assessed by measuring the activity of NADPH- and NADH-cytochrome c reductase. The results concerning the components of the oxidative defence systems in male rats showed reductions in the activity of superoxide dismutase and catalase in renal tissue and in factors of the glutathione system in liver tissue. In cardiac tissue an increased activity of catalase and elevated content of total glutathione were found. Vitamin E content was increased in liver and to a lesser extent, in kidneys. The activity of Se-dependent glutathione peroxidase sharply decreased only in liver. Major differences between male and female rats were not observed in renal and cardiac tissue, as far as protective factors were concerned. However, a decrease in catalase activity was detectable earlier in male kidneys. The protective factors in liver of female rats were far less susceptible to in vivo treatment with adriamycin, as compared to liver of male rats. Decreased activity of the cytochrome reductases was found in liver of male rats. In male renal tissue only cytochrome c reductase activity was significantly reduced. Male cardiac tissue showed no signs of biochemical damage, although from histological examination in a parallel study [J Natl Cancer Inst 76: 299-307 (1986)] lesions were evident. In female rats no damage was found in liver, kidneys and heart.

Effects of chronic administration of doxorubicin on plasma levels of prostaglandins, thromboxane B2, and fatty acids in rats

The effects of multiple doses of doxorubicin (DXR) on hematocrit and plasma levels of prostaglandins (PG), thromboxane B2 (TxB2), total lipid, esterified and free fatty acids, and proteins were investigated in male rats. The rats received DXR (2 mg/kg) or vehicle weekly by the subcutaneous route for 2, 4, 8, and 13 weeks and were killed 1 week after their last dose. Another group of rats treated for 13 weeks was sacrificed at 19 weeks, 6 weeks after the last dose. No changes in hematocrit or plasma PG, TxB2, or total levels of fatty acids were noted between control and DXR-treated rats at either 3, 5, or 9 weeks. The hematocrit was slightly depressed from control levels at 14 and 19 weeks. Plasma PGE, PGF2 alpha, and TxB2 were elevated over control levels at 14 and 19 weeks. Plasma 6-keto-PGF1 alpha was increased over the control level only at 19 weeks. Total plasma lipid and esterified fatty acids were highly elevated over control levels at 14 and 19 weeks. Plasma free arachidonic acid was elevated over control levels at 14 and 19 weeks, while levels of other free fatty acids were unchanged. Plasma protein levels were slightly depressed from control levels at 3, 9, and 14 weeks. Elevations of plasma free arachidonic acid, PG, TxB2, esterified fatty acids, and total lipid might be involved in cardiotoxicity and nephrotoxicity found with chronic administration of DXR.

Hyperlipidemic effects of adriamycin in rats

Adriamycin, an anticancer drug, caused dramatic increases in the serum lipid levels of rats fed a high-cholesterol diet. Male Lewis inbred rats were fed a basal or 1.5% cholesterol diet containing 0.5% cholic acid for 8 weeks. The rats were injected with adriamycin in doses of 1.5 mg/kg body weight, twice a week, and 6.0 mg/kg body weight, every other week. The serum lipid peroxide level gradually rose in adriamycin-treated rats, reaching a four-fold level at the end of the experiment. Cholesterol feeding, however, had a lowering effect on the lipid peroxide level. Adriamycin treatment or cholesterol feeding moderately elevated serum lipid levels, but their combination exerted a synergistic effect. In rats injected with a large dose of adriamycin and fed a high-cholesterol diet, the serum cholesterol, triglyceride and phospholipid levels strikingly increased by approx. 2000, 1500 and 1300 mg/100 ml, respectively. However, the ester ratio of cholesterol remained almost constant. Furthermore, serum GOT, GPT and ALP activities were only slightly different from the control values. Adriamycin treatment produced severe hypoalbuminemia. Ascites was also observed in rats given a large dose of adriamycin. The present findings indicate that the hyperlipidemia we observed may basically result from adriamycin-induced nephrosis and can be markedly enhanced when rats are fed a high-cholesterol diet. In spite of remarkably high levels of serum lipids and lipid peroxides, the aortic cholesterol level increased only slightly.

Toxic effects of chemicals: difficulties in extrapolating data from animals to man

This review attempts an analysis of the major components which make it extremely difficult to extrapolate toxicological data obtained with chemicals from animals to man. A first problem concerns the use of doses to express the unit of comparison across animal species; the dose is a parameter exogenous to the body and when a chemical enters the body concentrations should be utilized. There is in fact evidence that for several chemicals equal doses in different animal species do not mean equal concentrations in blood or tissues. Concentrations of chemicals should be measured for extrapolation purposes as close as possible to the site of the toxic effect. A second problem regards the fact that several chemical are transformed in the body into other chemical species--sometimes few and sometimes many--and some of these species (active metabolites) display biological activity in some cases higher than different from or antagonistic to those of the parent compounds. Some of these metabolites are highly reactive and therefore bind to body components, particularly macromolecules such as proteins and nucleic acids. There is evidence that metabolism is quantitatively and/or qualitatively different in various animal species. A third problem concerns the difference in various animal species in the biological substrates on which chemicals exert their toxic effects. Equal concentrations of chemicals and their metabolites do not mean equal toxic effects across animal species because endogenous metabolic processes, cell permeability, enzymes, and receptors are not necessarily the same in animals and man. To overcome these difficulties there is a need for closer integration of different disciplines in the toxicological evaluation of chemicals. A scientific rather than a routine approach in toxicology is emphasized.