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In previous trials we proved how propionyl carnitine, an acyl carnitine characterized by its intense mitochondrial metabolic, and cardio and vasoprotective activity, could prevent the cyclosporine-induced nephrotoxicity. Subsequently we also noted how propionyl carnitine could prevent the increase in renal intracellular calcium, which is the base of many cyclosporine-induced toxic phenomena. In our trials, we used the isolated and perfused rat kidney technique to examine if with the variations of the concentration of intracellular calcium, the adenosine 5'-triphosphate concentrations also varied, and if this decrease could be corrected by administrating propionyl carnitine. The results we obtained in these experiments indicated that when propionyl carnitine was administered preventively, the concentrations of renal intracellular adenosine 5'-triphosphate which were decreased by the cyclosporine returned to their normal values and, at the same time, a decrease in the increased vascular resistance of the kidney was noted. Therefore, propionyl carnitine corrected one of the biochemical alterations which explained the pathogenesis of the renal damage induced by cyclosporine.

In this study a comparison was made between results obtained from resveratrol dosages which have been shown to be pharmacologically active, in vitro and in vivo, and the results of plasma and tissue concentrations obtained after a single administration or after prolonged administration of red wine with a known resveratrol content. The dosages used by different investigators in the tests are very different and, in general, rather high in relation to the concentrations which are found in wine or grapes. The results of our tests on platelet aggregation confirm that even with modest dosages of resveratrol, a pharmacological effect can be observed, and that these dosages can be compatible with the resveratrol concentrations obtained after oral administration. The data obtained from these tests on animals can lead to the conclusion that even an average drinker of wine can, particularly in the long term, absorb a sufficient quantity of resveratrol to explain the beneficial effect of red wine on health, which has been observed in epidemiological studies carried out in populations whose daily diet includes the drinking of wine.

In view of the increasing interest in the biological activity of resveratrol, one of the components of red wine which is considered to be one of the main ingredients responsible for the beneficial effect of wine on human health, we have studied plasma kinetics and tissue bioavailability of this compound after red wine oral administration in rats. Plasma pharmacokinetics after oral administration of resveratrol could be described by an open one- or two-compartment model. Tissue concentrations show a significant cardiac bioavailability, and a strong affinity for the liver and kidneys.

The aim of the present study was to evaluate the absorption, the concentration in different organs and the excretion of natural trans- and cis-resveratrol after red wine oral administration to rats. A first group of animals was given a dose of 4 ml of red wine containing 6.5 mg/l of total resveratrol. The animals were sacrificed at different time intervals. A second group of rats was given a daily dose of 2 ml of red wine containing 6.5 mg/l of total resveratrol for fifteen days. Total resveratrol concentrations were measured in plasma, urine, heart, liver and kidney. Even though the amount of resveratrol found in these different tissues was lower than that required for pharmacological activity, it is possible that prolonged administration of red wine in the diet could lead to an increased resveratrol concentration in different tissues and this could explain its suggested beneficial role against coronary heart disease.

Kinetics of trans- and cis-resveratrol (3,4',5-trihydroxystilbene), a natural compound from grape products, have been evaluated in rats after oral administration of red wine. Resveratrol concentrations were measured in plasma, heart, liver and kidneys. Tissue concentrations showed a significant cardiac bioavailability and strong affinity for liver and kidneys.

Nephrotoxicity has represented the major limitation in the use of cyclosporine A (CyA). The structural abnormalities at the level of the proximal tubular cells are necrosis, vacuolisation and lipid droplets, as well as CyA-induced glomerular afferent arteriole constriction and granular juxtaglomerular cell hyperplasia. The mode of action of vasoconstriction is not well known, but there appears to be substantial impairment of endothelial cell function leading to enhanced release of vasoconstrictors such as endothelin and thromboxane. L-propionylcarnitine (PC), one of the most potent analogues of carnitine, is able to correct and to prevent alterations in endothelial membrane permeability and it has been identified in the kidney of various animal species. To investigate a possible reduction of CyA-induced nephrotoxocity, we examined the effects of a pretreatment with PC before administering several doses of CyA in an isolated and perfused rat kidney. The histological findings showed that the perfusion with PC reduces the vasoconstrictive effect of CyA on the glomerular capillaries and preserves the tubular epithelium. The ratio of the diameter between the glomerular capillary tuft and Bowman's capsule was higher, while at the tubular level the ratio internal-diameter/diameter evaluated at the level of the basal membrane was lower in PC + CyA perfused kidneys than in only CyA perfused ones. The final value of perfusion pressure was lower in PC + CyA perfused kidneys than in only CyA perfused ones, confirming the histological findings. The release induced by CyA of alanine aminopeptidase (AAP) and N-acetyl-glucosaminidase (NAG), markers of tubular damage, was significantly reduced by pretreatment with PC. These data suggest that the pretreatment with PC reduces the CyA-induced nephrotoxicity in an isolated and perfused rat kidney.

The effect of the infusion of calcitonin gene related peptide (CGRP) on the renal structure and enzyme release from tubular epithelial cells was studied. This study was performed in the model of an isolated perfused kidney to avoid the systemic effects and complex hormonal and neuromediated interaction following the CGRP infusion in the intact experimental animal. After infusion of CGRP, the perfused kidney, studied by semiquantitative histology and electron microscopy, did not show any alteration at the glomerular level; however, important histological lesions were apparent at the proximal tubular level: the brush border was destroyed and the epithelial cells were markedly flattened. This structural damage to epithelial cells was confirmed by electron microscopy. The alanine amino peptidase (AAP) and N-acetyl-glucosaminidase (NAG) were significantly increased in the effluent of the perfusion system, in confirmation of the histological damage. The direct toxic effect of CGRP on the tubular epithelial cells may be related to the reabsorption and tubular transport of this substance.

Outside the central nervous system, calcitonin-gene-related peptide (CGRP) plays an important role in the control of regional blood flow. The present authors studied the renal haemodynamic effects of CGRP in the model of isolated perfused rat kidney (IPRK). This experimental model avoids the complex feed-back mechanisms activated by any modification of renal perfusion pressure. It was found that the infusion of CGRP in the IPRK induced a marked decrease of perfusion pressure; this vasoactive effect is well measured by the glomerular morphometric analysis that shows a striking increase in the glomerular diameter and volume.

The aim of the present experiments was to ascertain whether prostacycline could exercise a protective effect against the formation of thrombosis in the rat tail induced by endothelin and K-carrageenin and to compare the effect of prostacycline with that of carnitine and propionyl carnitine. Both prostacycline and propionyl carnitine exhibited a similar protective effect on this experimental model. A combined protective effect of prostacycline administered with carnitine was also observed and a possible interaction between these two substances is proposed.

Propionyl carnitine can prevent endothelin and carrageenin-induced thrombosis in the rat's tail. This protective action of propionyl carnitine is probably related to its capacity to increase the synthesis of PGI2 prostaglandins and, subsequently, the amount of prostaglandins released by endothelin. Indomethacin, a well known prostanoid synthesis blocker, is unable to inhibit the protective activity of propionyl carnitine on endothelin-induced thrombosis after prolonged propionyl carnitine administration, but only a part of this protective activity after propionyl carnitine acute administration. Subsequently, other factors in addition to prostanoids seem to be involved in protective mechanisms of propionyl carnitine on endothelin-induced thrombosis.

This investigation was conducted to ascertain whether administration of L-carnitine and coenzyme Q10 could protect from the experimentally-induced hepatic lipid infiltration and glutathione content decrease in rats exposed to hyperbaric oxygen and prolonged alcohol administration. The results indicate that administration of L-carnitine and coenzyme Q10 in association reduces damage induced by chronic alcohol poisoning and hyperbaric oxygen. This protective action is more marked when L-carnitine and coenzyme Q10 are administered together. The combined complementary biochemical activity of these two compounds is discussed.

Propionyl carnitine, a derivative of carnitine, has metabolic and cardiovascular effects similar to carnitine but with more pronounced peripheral haemodynamic activity. In these experiments we propose to prove that the administration of propionyl carnitine could prevent the experimental tail thrombosis in the rat induced by endothelin (ET-1), serotonin and K-carrageenin. In this new test of experimental thrombosis, propionyl carnitine was able to reduce the extent of tail thrombosis in a more significant manner than that of carnitine. A possible explanation of this antithrombotic effect of propionyl carnitine is its capacity to counteract the vasoconstrictor activity of endothelin modulating the release of prostanoids induced by endothelin itself.

Tetrachloroethylene, an industrial halogenated solvent, shows several toxic effects. Also at hepatic level this substance can induce a damage but this effect is present only after high exposure, but such high levels have not been found in work environments. Using Wistar rats, we wanted to check whether the chronic administration of ethyl alcohol can modify the action of tetrachloroethylene. Tetrachloroethylene was administered by aerosol and alcohol at the concentration of 15% in drinking water. We observed an increase in plasma triglycerides, and evident histological alteration as a result of steatosis, in rats drinking alcohol as compared to a control group; the administration of tetrachloroethylene to rat drinkers of alcohol did not cause an increase in plasma triglycerides and steatosis as compared to rat drinkers of alcohol, but on the contrary we observed a decrease in alcohol-induced liver damage.

Many vasal factors are produced during an experimental model of inflammation such as rat-paw oedema induced by carrageenin. We investigated whether among the other well-known mediators of inflammation, i.e. serotonin, PAF, eicosanoids and kinins, the peptide endothelin-1 is produced by this kind of inflammatory process caused by carrageenin. Our results indicated that plasma endothelin, and the tissue concentration of endothelin in the oedematous paw, is increased as compared to the control. Consequently, endothelin should also be considered as an important factor in inflammatory processes.

Endothelin-1 (ET-1) is an amino peptide produced by endothelial cells with a potent vasoconstrictor activity; this effect is regulated by a release of other endogenous vasal factors. Recent studies have demonstrated that endothelin is capable of releasing from different tissues, and particularly from perfused organs such as spleen and kidney, many vasal factors and prostanoids. The present study investigates whether perfusion with a solution of endothelin-1 in rat isolated kidney can induce the release of histamine, another vasal factor (until now not investigated in relation with endothelin-1) and whether treatment with propionyl carnitine, a compound with vasoprotecting activity, inhibits this release. This research demonstrates that histamine released by rat kidney perfused with endothelin is lowered if previously treated with propionyl carnitine. This effect of propionyl carnitine can be considered to be another important factor in a complex mechanism involved in its vasoprotective and cardiovascular action.

The ethanol-induced increased synthesis of fatty acids in the liver is enhanced by hyperbaric oxygen exposure. Both lipid peroxidation and glutathione depletion are involved in these hepatic alterations. Coenzyme A can intervene in these mechanisms. The administration of CoA prevents hepatic lipid infiltration and the glutathione reduction induced in the rats by ethanol and hyperbaric oxygen exposure.

Paracetamol toxicity induced in mice a significant depletion in hepatic and renal glutathione concentrations. The administration of CoA in animals prevents the mortality induced by paracetamol and simultaneously prevents the reduction in renal and hepatic glutathione concentrations.

Coenzyme Q10 (CoQ10) distribution into rat liver, heart, kidney and plasma was investigated after intravenous and oral administrations in different vehicles. Moreover, CoQ10 skin levels following topical treatment were evaluated. The liver represented the target organ for this compound in all the cases examined. In the heart, high and persistent CoQ10 concentrations were achieved particularly after solution injection while, following oral treatment, high doses of the drug were needed to reach the same CoQ10 levels. High concentrations of CoQ10 may be achieved also in the skin by topical treatment.

The platelet-activating factor (PAF) has been shown to stimulate the release of prostaglandins, leukotrienes and 5HT from a number of cell types. In this work we studied the effects of bolus injections of PAF on the isolated perfused rat kidney. Results showed histological damage at the proximal-tubule level and a significant histamine release.

Coenzyme Q10 (CoQ10) kinetics was investigated in rat tissues after oral treatment. CoQ10 passes quickly from plasma into the tissue examined, reaching levels higher than physiological ones; the liver shows the maximal CoQ10 concentrations. Our results indicate that oral treatment makes it possible to obtain good tissue levels of CoQ10 that might be of clinical value against endogenous CoQ10 insufficiencies due either to pathological alterations and/or to drug administration.

An investigation was undertaken of the capacity of thepirubicin (THP), a new anthracycline derivative with reduced cardiotoxicity, to be fixed in the myocardial fibre, as compared with that of adriamycin hydrochloride (ADR), using a method based on the histofluorescence of tissues treated in vivo with anthracyclines. Histological examination of heart sections from rats perfused with either THP or ADR showed similar results. The major difference was the lower quantitative localization of THP in the cytoplasm, although this quantitative difference was not so pronounced in the nuclei. This suggests that cardiac lesions may be due not to the basic action of anthracyclines on DNA but to collateral effects not yet identified.

The protective action of hepatic cells of the coenzyme CoQ10 was checked against the well-known hepatolesive agent carbon tetrachloride (CCl4). It was found that CoQ10 pretreatment strongly reduced the CCl4-induced lesions in rat liver. The most important of these lesions was a marked steatosis, together with focal necrosis, Kupffer-cell reaction and signs of phlogosis and fibroblastic proliferation. The protective effects of CoQ10 seemed to be dose-dependent. The variation of CoQ9 concentration in the liver was not significant at any of the doses used.

Rat kidney was perfused using Krebs solution containing 3 or 6 mEq/l lithium or 3 or 6 mEq/l rubidium; the histological lesions thus induced were compared. Rubidium-induced lesions, irrespective of concentrations, consisted of tubular dilations, degeneration and necrosis very similar to those induced by lower concentrations of lithium; moreover, Bowman space alterations were observed. In contrast, lithium-induced damage was dose-dependent: 6 mEq/l solution induced severe tubular damage with necrosis, endoluminal cellular debris and hyaline substance.

The nephrotoxicity of aminoglycosides has been the object of numerous works of research showing that different molecules belonging to the same family of antibiotics can exert their toxic action in different ways. The aim of the present research was to evaluate the nephrotoxicity of dactimicin (DTC), a recently synthesized aminoglycoside antibiotic, as compared to gentamicin (GTM), amikacin (AMK) and fortimicin (FTM). The experimental model used was the isolated perfused rat kidney, and the parameters evaluated were histamine release and histological findings. The results showed that GTM was able to induce a significantly higher release of histamine than AMK, FTM, or DTC. AMK provoked a higher level of histamine release than FTM or DTC, although the differences between the three were not significant. Histological preparations obtained with GTM revealed large-scale lesions, which however were less detectable with AMK, and much less with DTC.

Male Wistar rats received adriamycin, aclacinomycin or thepirubicin at a dose of 4 mg/kg b.w. by slow infusion. Cardiac tissue sections were examined by fluorescence microscopy to evaluate the distribution of the three anthracyclines. The nuclei regularly exhibited a stronger coloring with respect to the cytoplasm for all three drugs. Adriamycin cytoplasm fluoresced intensely, unlike aclacinomycin and thepirubicin. Our results indicate a lower uptake of these last two molecules into cardiac tissue, thus suggesting a different pharmacokinetic profile which might account for their lower cardiotoxicity.

Dactimicin (DC) is a new pseudodisaccharide aminoglycoside antibiotic containing a formimidoyl group in its molecule (1). DC exhibits a greater antibacterial activity than other aminoglycosides against the clinical isolates of Serratia marcescens and is active against many gentamicin- and amikacin-resistant bacteria. This characteristic of the drug appears to be linked with a probable protective action exerted by the formimidoyl group in its structure. The greatest limitation in the clinical use of aminoglycosides is their potential for nephrotoxicity. The present study compares the renal effects of DC versus gentamicin (GT) and amikacin (AK), respectively the most and the least nephrotoxic pseudotrisaccharide aminoglycosides in present use (2), evaluating the urinary NAG excretion and the histological changes induced in the kidney.

The action of PAF is involved in various biological activities, including alterations at the renal level. Previous experiments of ours have shown that PAF is capable of inducing histamine release at this level, and causing histological damage in the isolated perfused rat kidney. On the basis of these observations, the same experimental model was used to evaluate the release of enzymes such as NAG and alpha-glycosidase, which are precocious markers of renal damage. Results show that both NAG and alpha-glycosidase increase after PAF administration.

Dactimicin (ST 900) is a new pseudo-disaccharide aminoglycoside antibiotic which has been shown to be active against systemic infections in mice. Few data have so far been reported on dactimicin tissue accumulation or its potential nephrotoxicity. In this study, nephrotoxicity and renal tissue concentrations of gentamicin, amikacin and dactimicin were compared in Wistar rats. Liver, heart and lung accumulation of these drugs were also evaluated. Groups of 5 rats were respectively injected with 100 mg/kg body weight of the different drugs daily for 7 days. Five control rats were also injected with saline. Twenty-four hours after the last injection, all rats were sacrificed and bled to death. Blood samples were taken for BUN and serum creatinine assay. Kidney, liver, heart and lung tissues, as well as blood, were removed and processed for microbiological assay of gentamicin, amikacin and dactimicin. The results of this study showed that dactimicin, as well as amikacin, did not induce any significant increase in BUN and serum creatinine, while gentamicin administration resulted in severe uraemia in all rats. Consequently a much higher accumulation of gentamicin than amikacin and dactimicin was achieved in serum and tissues.

This study was undertaken to investigate aclacinomycin distribution in the rat, using a method based on the histofluorescence of tissues treated in vivo with anthracyclines. The target organs were the kidney, lung and pancreas; a fainter fluorescence was also detected in the heart compared with adriamycin due to a quantitatively different fixing of the two anthracyclines. Our findings revealed a preferential uptake into the cell nucleus in all tissues examined except the adrenal gland medulla where a slight fluorescence appeared only in the cytoplasm.

Skin penetration of coenzyme Q10 (CoQ10) was investigated after topical treatment in the rat. The drug was suspended in olive oil and administered at two different concentrations. Coenzyme levels were found to be directly related to the concentrations employed and the contact time. CoQ10 topical treatment might therefore be proposed as a good pharmacological tool in dermatology and cosmetology.

Investigations were carried out into morphological differences between the uptake of adriamycin and its 13-OH metabolite adriamycinol into rat liver and heart. In the liver parenchyma, adriamycinol is mainly stored in the central area of the hepatic lobule, while adriamycin shows a more uniform distribution. In cardiac tissue, adriamycin accumulates within chromatin masses, whereas adriamycinol scarcely enters myocardial cells. The cardiotoxicity of both anthracyclines might be related to interactions with cytomembrane binding sites.

Coenzyme Q10 (CoQ10) distribution into rat liver, heart, kidney, and plasma was investigated after intravenous administration in microsphere delivery system and in solution. The liver represented the target organ for this compound in both cases. Higher plasma levels of CoQ10 were achieved after solution treatment. No significant differences were detected in the other tissues examined.

Dactimicin is a new aminoglycoside antibiotic with an interesting low nephrotoxicity in animal experimental models. In order to establish if a correlation exists between the nephrotoxic effect and renal pharmacokinetic behaviour of aminoglycosides, tobramycin, sisomicin and dactimicin were studied in a model of isolated and perfused rat kidney. Concentrations in venous and urinary effluent during a continuous perfusion of a constant concentration of drugs were evaluated. The influence of active transport was studied comparing excretion data obtained with perfusion buffer with or without glucose. In the present experimental model the renal excretions of the aminoglycosides tested are quite similar and cannot account for the different nephrotoxicity observed in animals.