Oral Administration Of Cyclosporin A Research Articles

A new nanosuspension prepared with wet milling method for oral delivery of highly variable drug Cyclosporine A: development, optimization and in vivo evaluation

Cyclosporine A (CsA) is a cyclic polypeptide, that has been widely used for immunosuppression. This study aims to develop nanosuspension for oral administration of CsA using the wet milling (WM) method one of the top-down technologies. The WM method was optimized by studying the effects of critical process parameters for WM on the particle size (PS), particle size distribution (PDI), and zeta potential (ZP) of nanosuspensions using the Design of Experiment (DoE) approach. Nanosuspension was developed using hydroxypropyl methylcellulose (HPMC) and sodium dodecyl sulfate (SDS) and in vitro characterization studies were performed. In vitro dissolution and in vivo pharmacokinetic studies were conducted with biorelevant media (fasted and fed state simulated fluids) and fasted and fed states in rats, respectively. In vivo immunological studies were also performed. PS, PDI, and ZP values for nanosuspension were approximately 600 nm, 0.4, -25 mV, respectively. The solubility of CsA was increased by 4.5-folds by nanosuspensions. Dissolution studies showed that nanosuspension had higher dissolution than the commercial product in the FeSSIF medium. The pharmacokinetic study indicated that AUC0–24 values of CsA nanosuspension were to be 2.09 and 5.51-fold higher than coarse powder in fasted and fed conditions, respectively. Immunological studies were carried out after oral administration of nanosuspension for 21 days, the ratio of CD4+/CD8+ was found to be more acceptable than the commercial product. These results demonstrated that nanosuspension is a promising approach for increasing the bioavailability and avoiding the food effect on absorption of CsA which one of the highly variable drugs.

Optimal sampling time‑point for cyclosporin A concentration monitoring in heart transplant recipients

The present study was performed to determine an optimal time-point for monitoring the concentration of the immunosuppressive drug cyclosporin A (CsA) in heart transplant patients and its efficacy in the prevention of transplant rejection. A total of 32 transplant recipients were randomly assigned for three treatment approaches. Recipients in groups A (n=11), B (n=13) and C (n=8) received oral administration of CsA at doses of 3.2, 3.5 and 4.4 mg/kg, respectively. The plasma CsA concentrations were examined at 2 h intervals over 12 h. Furthermore, their correlation with the 4 h pharmacokinetic profiles as the area under the plasma CsA concentration vs. time curve (AUC0-4 h) were calculated The efficacy of CsA in inhibiting cardiac allograft rejection was assessed at 2 h after oral CsA intake (C2) and adverse events of the drug were examined in the C2-monitored recipients. The plasma CsA concentration rapidly increased in most recipients with a peak level detected at ~2 h after dosing. Regression analysis revealed that among all time-points assessed, the CsA had the highest correlation with the AUC0-4 h at C2. At C2, increasing CsA doses exhibited a positive association with the measure of AUC0-4 h. The efficacy of increasing CsA target levels at C2 in preventing heart transplant rejection was comparable, as the survival rate was 100% in all of the treatment groups. However, the proportion of recipients with side effects in group A was obviously lower than that in the other two groups. In conclusion, C2 is an ideal time-point for monitoring plasma CsA levels with a utility for individualising the next scheduled dose for each patient to ensure that target levels are maintained and achieve a high efficacy and safety of CsA therapy in heart transplant recipients (clinical trial no. 12002610).

Klotho mitigates cyclosporine A (CsA)-induced epithelial-mesenchymal transition (EMT) and renal fibrosis in rats.

Klotho deficiency is implicated in various kidney diseases, including renal fibrosis. The aim of this study was to investigate the effect of Klotho administration on epithelial-mesenchymal transition (EMT) and renal fibrosis induced by cyclosporine A (CsA) in rats. CsA-induced renal fibrosis was established by oral administration of CsA (30mg/kg) to rats on a low-salt diet for 28days. Klotho was administered to rats by intraperitoneal injection. Renal pathological changes were evaluated by hematoxylin and eosin and Masson's trichrome staining. The EMT response was assessed by measuring the level of TGF-β1, E-cadherin and α-SMA by immunohistochemistry and Western blot. Administration of CsA for 28days induced renal damage, decreased Klotho expression and activated the EMT response (demonstrated as increased TGF-β1 and α-SMA expression accompanied by decreased in E-cadherin expression). Treatment with Klotho significantly ameliorated pathological lesions of the kidney by modulating the expression of EMT-associated proteins in the kidney. Klotho inhibits CsA-induced EMT and renal fibrosis in rats. Klotho may serve as a therapeutic agent to minimize CsA-induced renal fibrosis.

The Role of Coenzyme Q10 against Cyclosporine-A Induced Cardiotoxicity in Adult Male Albino Rats (Histological and Toxicological Study)

Cyclosporine-A (CsA) has a potent immunosuppressive activity and is commonly used as anti-rejection drug after organ transplantation and for treatment of some autoimmune diseases. Several toxic effects on the cardiovascular system have been reported with CsA therapy. The toxicity induced by CsA is attributed to the formation of free oxygen radicals. Coenzyme Q10 (CoQ10) is a fat soluble, vitamin-like benzoquinone compound that functions primarily as an antioxidant, and a cofactor in the oxidative phosphorylation processes. The level of CoQ10 is reduced under the conditions of illness for example after renal transplantation. The present study was done aiming to detect the possible morphological and structural changes that may occur in the cardiac muscle of the adult male albino rats duo to CsA therapy and to test the protective effect of CoQ10 against CsA-induced cardiotoxicity. Thirty adult male albino rats were used in this study. They were classified into 3 groups and orally given the following materials for 28 days: Group (1) (Control group): that was further subdivided into 2 equal subgroups, each of 5 animals: subgroup 1a: received olive oil 1 ml/kg. Subgroup 1b: (CoQ10 group): received 5 mg/kg/day of CoQ10. Group (2) (CsA-treated group): The rats received 25 mg/kg/day of CsA. Group (3)(CoQ10 & CsA treated group): The rats were treated with the previously mentioned doses of both CoQ10 and CsA. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were recorded three times per week. At the time of sacrifice, the hearts were dissected out and processed for light and electron microscopic examination. Oral administration of CsA, produced a significant (p<0.05) elevation in SBP, DBP, and HR in comparison to the control group. Treatment with CoQ10 significantly (p<0.05) reduced the increments in arterial blood pressure and heart rate. However, the recorded values were still significantly (p<0.05) higher than that of the control group. The light microscopic study of sections of cardiac muscle of CsA-treated adult male albino rats showed increase in the number of infiltrated cells and disorganization of myocardial fibers with increase in the amount of connective tissue and interstitial fibrosis with perinuclear cytoplasmic vacuolation and decrease in the amount of myofilaments. Electron microscopy showed distension of the Z lines with disintegration of some of them, loss of some microfilaments and disorganized intercalated discs. CoQ10 partially prevented most of the pathological changes revealed by the light and electron microscope. From the above mentioned results we could conclude that treatment with CoQ10 partially prevented the CsA-induced cardiotoxicity in adult male albino rats. We could recommend using CoQ10 during CsA therapy to prevent its cardiotoxicity.

Long-Lasting Inhibition of the Intestinal Absorption of Fexofenadine by Cyclosporin a in Rats

The purpose of the present study is to examine the long-lasting inhibition of intestinal organic anion transporting polypeptides (Oatps) by cyclosporin A (CsA) in rats using fexofenadine (FEX) as a probe drug. We examined the pharmacokinetics of FEX after its intravenous or oral administration to rats at 3 or 24 h after the oral administration of CsA. When FEX was administered at 3 h after the administration of CsA, its plasma concentration increased regardless of whether it was administered intravenously or orally. When FEX was intravenously administered at 24 h after the oral administration of CsA, its plasma concentration was increased; however, that observed after its oral administration was not significantly different from the vehicle-treated control. When FEX was administered at 3 h after the administration of CsA, the hepatic availability (F(h)) and the fraction absorbed in the intestine as an unchanged form (F(a)·F(g)) of FEX were increased, resulting in increased bioavailability (=F(a)·F(g)·F(h)). At 24 h after the administration of CsA, the F(h) of FEX was increased, whereas its bioavailability was decreased, suggesting that its F(a)·F(g) was decreased because of the long-lasting inhibition. In conclusion, CsA has long-lasting inhibitory effects on Oatps in the rat intestine as well as in the liver.

Protective effect of Phyllanthus niruri against cyclosporine A-induced nephrotoxicity in rats

Phyllanthus niruri (Euphorbiaceae) is a popular plant in folk medicine, whole plant, fresh leaves, and fruits are used in the treatment of various diseases. In the present study, nephroprotective potential of aqueous extract of P. niruri was investigated against cyclosporine A (CsA) induced changes in kidney of Wistar rats. Nephrotoxicity was induced by oral administration of CsA (25 mg/kg/b.w.) dissolved in olive oil for a period of 21 days. Nephrotoxicity induced rats were treated with aqueous extract of P. niruri (200 mg/kg/b.w.) for a period of 21 days. Levels of serum creatinine and blood urea nitrogen, renal marker enzymes in serum and different enzymic and non-enzymic antioxidants, lipid peroxidation products, as well as ATPases in kidney homogenates were measured in normal, control (toxicity induced), and P. niruri treated rats. Histopathological studies were also been carried out. Administration of CsA increased the serum levels of creatinine and blood urea nitrogen, alkaline phosphatase, alanine aminotransaminase, and lactate dehydrogenase thereby indicating damage to kidneys. Increased lipid peroxidation and a decrease in antioxidants enzymes were observed in toxicity-induced rats. The levels of membrane-bound ATPases were also significantly altered. Upon administration of P. niruri, the levels of serum creatinine and blood urea nitrogen and also lipid peroxidation were found to be markedly reduced. Renal antioxidant defense systems, such as superoxide dismutase, catalase, glutathione peroxidase activities and reduced glutathione, and vitamins e and c, depleted by cyclosporine A, were restored to normalcy by treatment with the extract. The drug also effectively attenuated renal dysfunction and normalized the altered renal morphology and also restored the activities of renal ATPases. The results suggest that the nephroprotective effect of P. niruri could be due to the inherent antioxidant and free-radical scavenging principle(s) contained in the extract. In conclusion, our study indicates that P. niruri through its antioxidant activity effectively salvaged CsA induced nephrotoxicity.

The effective therapy of cyclosporine A with drug delivery system in experimental colitis

Cyclosporine A (CyA) is a useful immunosuppressive agent for steroid-dependent or steroid-refractory ulcerative colitis. However, side effects have been reported in clinical trials of ulcerative colitis treated with CyA. Biodegradable microspheres (MS) have been investigated as drug delivery system. We evaluated the effect of a drug delivery system with poly(d,l-lactic acid)-MS containing CyA. Colitis was induced in C57BL/6 mice by 3% dextran sulfate sodium (DSS). Mice with DSS-induced colitis were treated with oral administration of CyA or CyA-MS: CyA (0.2 mg/kg/day)-MS; CyA (2 mg/kg/kg)-MS). Serum levels of CyA were significantly less elevated after oral administration of CyA (2 mg/kg/day)-MS compared with CyA (2 mg/kg/day) (CyA (2 mg/kg/day), 44.7 ± 0.8 ng/ml; CyA (2 mg/kg/day)-MS, 7.7 ± 1.3 ng/ml). The body weight at day 10 was significantly recovered in the mice treated with CyA (0.2 mg/kg/day)-MS and CyA (2 mg/kg/day)-MS compared with CyA (0). The histological score and myeloperoxidase activity in the mice treated with CyA-MS was significantly lower than CyA (0). Gene expressions of interleukin-1β (IL-1β), IL-6, and CXCL1 in the mice treated with CyA (0.2 mg/kg/day)-MS and CyA (2 mg/kg/day)-MS were downregulated compared with CyA (0)-MS. CyA-MS might be possible to treat ulcerative colitis effectively by decreasing the total dosage without the elevation of the serum level or the side effects of CyA.

Effect of ellagic acid on cyclosporine A‐induced oxidative damage in the liver of rats

Cyclosporine A (CsA) is an immunosuppressor, which is most frequently used in the transplant surgery and in the treatment of autoimmune diseases. It has been shown that CsA is able to generate reactive oxygen species and lipid peroxidation, which are directly involved in the CsA nephrotoxicity, hepatotoxicity and cardiotoxicity. This study was undertaken to investigate the protective effect of ellagic acid (EA), a polyphenolic compound against CsA-induced liver injury in male Wistar rats. In this study, CsA was administered orally (25 mg/kg body weight) for 21 days to induce toxicity. EA was administered orally (12.5, 25 and 50 mg/kg body weight) for 21 days along with oral administration of CsA. CsA-induced liver damage was evidenced by increased activities of serum hepatic enzymes namely aspartate transaminase, alanine transaminase, alkaline phosphatase and lactate dehydrogenase with a significant elevation of lipid peroxidation markers such as thiobarbituric acid reactive substances (TBARS) and hydroperoxides in the liver. The levels of enzymic antioxidants such as superoxide dismutase, catalase and glutathione-S-transferase and non-enzymic antioxidants (vitamin C, vitamin E and reduced glutathione) were also decreased in CsA-treated rats. Administrations of EA at 50 mg/kg body weight significantly decreased the activities of hepatic marker enzymes compared with other doses of EA (12.5, 25 mg/kg body weight). In addition, the levels of TBARS and hydroperoxides were significantly decreased and the levels of enzymic and non-enzymic antioxidants significant increased on treatment with EA in the liver. The biochemical observation was supplemented by histopathologic examination of liver section. The results of this study indicate that EA might play an important role in protecting CsA-induced oxidative damage in the liver.

Effects of oral administration of ciclosporin A on skin carcinogenesis: a study using the two-stage carcinogenesis protocol in mice

Development of malignant skin neoplasms in patients receiving cyclosporin A (CsA) has been reported. The relationship between the pathogenesis of skin carcinogenesis and the dose of CsA is still unclear. To clarify the effect of oral administration of CsA, especially its dose, on skin carcinogenesis. Hr-1 hairless mice were assigned to the following four groups: (i) control group (n = 8), given vehicle intragastrically six times/week and acetone applied to the skin of the back; (ii) chemical-alone (n = 11), given vehicle intragastrically + application of 7,12-dimethylbenz[a]anthracene (DMBA) once week and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) twice week to the back; (iii) CsA-alone group (n = 8), given CsA intragastrically (10 mg/kg) six times/week and vehicle applied to the back twice week; and (iv) CsA + chemical group (n = 8), given 10 mg/kg CsA intragastrically + topical DMBA and TPA. The number of papules > 3 mm in diameter that had developed on the back after 15 weeks was counted. The mean epidermal thickness and number of dermal infiltrates were determined. The same experiments were performed using CsA at doses of 5 and 20 mg/kg. Oral administration of either 10 or 20 mg/kg CsA significantly enhanced the formation of papillomas by DMBA and TPA, but no enhancement was observed when 5 mg/kg CsA was administered. The mean epidermal thickness and number of dermal infiltrates were significantly greater in the CsA + chemical group than in the chemical-alone group. These data suggest that oral administration of CsA in excess of a certain dose can accelerate tumour development in mice.

Cyclosporin A Kinetics in Children after Stem Cell Transplantation.

Introduction and aim of study. Cyclosporin A (CsA) is commonly used as prophylaxis against Graft versus Host disease (GVHD) after allogeneic haematopoietic stem cell transplantation (SCT). Therapeutic drug monitoring is necessary because of its unpredictable absorption and narrow therapeutic window. Usually dose adjustments are based on trough levels, although these correlate poorly with CsA systemic exposure in adults. The aim of this study was to investigate intravenous and oral CsA pharmacokinetics in children after SCT and to develop a limited sampling strategy in order to determine CsA systemic exposure.Methods. Pharmacokinetics was investigated in children, aged 1.8 to 16.1 yrs, 2 to 43 days after stem cell infusion (median: 25 days), after intravenous or oral administration of CsA in, respectively, 9 and 8 children. Parameter estimation was performed using nonlinear mixed effect modeling as implemented in the NONMEM program.Results and conclusions. Pharmacokinetics were described adequately with a two-compartment model with lag time (population estimates: Cl=10.5 l/h; Vc=15.5 L; Vp=60.6L; t ½ absorption=1.01 h, Tlag=0.6 h). Combination of Cthrough and a Bayesian fitting procedure with the pharmacokinetic model can adequately estimate the systemic exposure to CsA (r2=0.90, Figure 1). The estimation of actual AUC improves when more concentration time-points are used. No relation between body weight and clearance was found (Figure 2). Based on these data, CsA should not be dosed per kilogram body weight. A regimen with a fixed dose for all, adjusted on through levels in combination with the described pharmacokinetic model, may be more appropriate. (open circles: oral administration; closed circles: intravenous administration) [Display omitted] [Display omitted]

Distribution of cyclosporin A in the cornea after topical or oral administration.

The purpose of this study was to determine levels of cyclosporin A (CsA) in ocular tissues and fluids after oral or topical administration of CsA in humans requiring immunosuppression for penetrating keratoplasty and to evaluate the sensitivity of a high performance liquid chromatography coupled to electrospray mass spectrometry (LC-MS). High-risk penetrating keratoplasty was performed on 11 patients requiring 5 mg/kg of oral cyclosporin A and 9 patients with topical 0.5% (suspension, equivalent to 5 mg/ml)) preoperative immune suppression. Venous blood samples, as well as aqueous samples, were obtained for some patients, and the central 6.0-8.5 mm corneal buttons were removed and dissected into cornea epithelium, stroma and endothelium and analyzed for CsA levels by LC-MS. The mean values (concentration) of the specimens analyzed (obtained from 11 patients on oral CsA) showed 2.45 +/- 2.12 and 0.35 +/- 0.49 ng CsA/mg tissue in the epithelium and endothelium, respectively. A much smaller concentration, 0.13 +/- 0.14 ng CsA/mg tissue was observed in the stroma. There was a fair amount of CsA in the serum at the time of surgery but no detectable CsA in all aqueous humor samples analyzed. In cases of topical application, the mean concentration of CsA was similarly highest in the epithelium, 64.29 +/- 39.92 ng CsA/mg tissue, followed by the endothelium, 9.98 +/- 6.55 ng CsA/mg tissue, with the lowest levels found in the stroma. Topical application of CsA is able to achieve high levels of CsA in the corneal epithelium, higher than that achieved from oral administration of CsA.

各種シクロデキストリンによるシクロスポリンＡの消化管吸収およびリンパ移行の改善

The solubility of cyclosporin A (CYA), an immunosuppressive drug, in water increased with a rise in hydrophilic cyclodextrin (CyD) concentrations, forming higher-order complexes. The solubilizing ability of hydrophilic CyDs for CYA increased in the order γ-CyD<β-CyD<α-CyD<<2, 6-dirnethyl-β-CyD(DM-β-CyD)≈DM-α-CyD. The oral bioavailability of CYA was increased about 4.5-fold by the complexation with DM-CyDs, and the variation of CYA absorption from gastrointestinal tracts was significantly decreased. On the other hand, the lymphatic transfer of CYA was hardly affected by the hydrophilic CyDs including DM-CyDs. Acylated β-CyDs that all hydroxyl groups of β-CyD are substituted with acetyl, butanoyl and octanoyl groups, were used as slow release carriers for CYA. When CYA/acylated β-CyDs complexes were administered orally, both plasma and lymph concentrations of CYA were prolonged up to at least 36 h, although the bioavailability decreased particularly for the butanoyl and octanoyl β-CyDs complexes. Interestingly, triacetyl-β-CyD complex increased both plasma and lymph concentrations of CYA compared with drug alone. The oral administration of CYA as an olive oil solution significantly enhanced the lymph levels of CYA. The CYA/olive oil solution in combination with HP-CyDs, especially HP-γ-CyD, further increased plasma and lymph levels of CYA. These results suggest that DM-CyDs are particularly useful in improving the oral bioavailability of CYA, while hydrophobic acylated β-CyDs are useful as a prolonged-release carrier for CYA. The CYA/olive oil solution in combination with HP-γ-CyD was proved to facilitate the lymphatic transfer of CYA.

Effect of streptozotocin-induced diabetes on cyclosporin A disposition in rats.

We studied the effect of diabetes on the pharmacokinetics of cyclosporin A (CyA) after intravenous and oral administration of CyA using the plasma and lymph of streptozotocin (STZ)-induced diabetic rat. There were no significant differences in the systemic and lymphatic availabilities after intravenous administration of CyA in diabetic rats compared with those of the controls. On the other hand, systemic and lymphatic availabilities after oral administration of CyA were significantly different in diabetic rats compared to those in the controls. These results suggest that the pharmacokinetics of CyA, particularly absorption, were altered in diabetic rats. Gastrointestinal transit in diabetic rats was also studied. The gastric emptying rate in diabetic rats was enhanced compared with that of the controls, but small intestinal transit was reduced in diabetic rats, suggesting that a change in gastrointestinal transit in diabetic rats may influence the absorption of CyA. The increased absorption of CyA from the digestive tract of diabetic rats altered not only the systemic availability but also the lymphatic availability, suggesting that altered systemic availability may cause adverse effects and that altered lymphatic availability may influence the immunosuppressive effects.

Effect of recombinant atrial natriuretic peptide (r-ANP) on ischemic and cyclosporine-induced kidney damage in rats

Cyclosporine A (CYA) a new immunosuppressive drug, has greatly improved the outcome of solid graft transplantation. The nephrotoxicity of CYA, however, is a serious problem, and constitutes the major obstacle limiting the use of CYA as an immunosuppressive agent for renal transplantation. On the other hand, the newly described atrial natriuretic peptide (ANP) hormonal system in both humans and animals appears to play an important role in sodium and water excretion. The present study examined the nephrotoxicity of CYA and the effect of recombinant-ANP (r-ANP) on the damaged kidneys in three groups. Group 1 consisted of rats with 45 minutes warm ischemic left kidney and right nephrectomy [WI rats]; Group 2 consisted of WI rats with oral administration of CYA (100mg/kg/day) for 2 weeks [WI+CYA rats]; Group 3 consisted of WI+CYA rats with intraperitoneal administration of r-ANP (10ng/kg/day) for 2 weeks. Group 2 had lower glomerular filtration rates (GFR) and renal plasma flow (RPF) than Group 1, but Group 3 had significantly higher GFR and RPF than Group 2. Additionally, in order to demonstrate the change in renal viability among the three groups, the adenosine triphosphoric acid level (ATP) and adenylate energy charge ratio (EC) of renal parenchymal tissue were measured by high performance liquid chromatography (HPLC). Group 2 had lower ATP and EC than Group 1, and Group 3 had higher ATP and EC than Group 2. The results of this study suggest that r-ANP is efficacious on rat kidney damage induced by CYA and WIT.

In vivo characterization of the anti-inflammatory effect of cyclosporin A on human basophils.

We investigated whether cyclosporin A (CsA) in vivo exerts anti-inflammatory effects by inhibiting IgE- and non-IgE-dependent mediator release from human basophils. Six healthy volunteers were given oral CsA (5 mg/kg twice daily) or placebo for 5 days. Plasma CsA and basophil releasability in response to anti-IgE, FMLP, and A23187 were monitored 1 day before treatment, on alternate days during the treatment course, and 1 and 8 days after cessation of treatment. A constant plasma level of approximately 250 ng/ml CsA was obtained during CsA treatment. Basophil releasability in response to anti-IgE, FMLP, and A23187 was diminished by 20 to 60% throughout the course of CsA treatment. Placebo had no effect on basophil releasability. There was a significant correlation between plasma CsA and the decrease of histamine release induced by anti-IgE (rs = -0.66; p < 0.0005), FMLP (rs = -0.59; p < 0.001) and A23187 (rs = -0.68; p < 0.0001). In a second study, eight normal volunteers were given a single oral dose of CsA (7 mg/kg) or placebo, and plasma CsA and basophil releasability were monitored at different times thereafter. A rapid and significant reduction of histamine release induced by anti-IgE, FMLP, and A23187 paralleled a sharp increase of CsA plasma levels, which peaked at 5 h and lasted approximately 13 h. This study indicates that oral administration of CsA in normal subjects causes a rapid and significant inhibition of histamine release from basophils. This is the first evidence that in vivo administration of CsA can modulate the release of proinflammatory mediators from basophils obtained ex vivo.

Characterization of the inhibition of renal translation in the Sprague-Dawley rat following in vivo cyclosporin A

"Run-off" translation assays in microsomes isolated from Sprague-Dawley rats were used to examine the capacity of cyclosporin A (CsA) to alter translation elongation. CsA added in vitro in concentrations of up to 100 micrograms/ml did not reduce "run-off" translation measured as 3H-L-leucine incorporation in microsomes isolated from the rat kidney or thymus. In contrast, the oral administration of CsA at 50 mg/kg/day for 6 days resulted in reductions in 3H-L-leucine incorporation by microsomes isolated from rat kidneys and unstimulated thymus to 21.6 and 83.0% of control values, respectively. In cross-over experiments between renal microsomal and cytoplasmic fractions, 3H-L-leucine incorporation was inhibited following the addition of renal cytoplasm from CsA treated rats to renal microsomal fractions from control vehicle treated rats. Translation inhibition was still observed when renal cytoplasm from CsA treated rats was added along with renal cytoplasm from control rats to renal microsomes isolated from rats treated with control vehicle. Reductions in renal 3H-L-leucine incorporation were not due to a stimulation of renal protease activity. Experiments varying the concentration of individual components of the microsomal translation assays suggested that renal microsomes from CsA treated animals were saturated with substrate or cofactor at lower concentrations than control microsomes. Time course experiments showed a marked reduction in the duration and extent of 3H-L-leucine incorporation by renal microsomes from CsA treated animals compared to controls. Sucrose density gradient analysis of microsomes from CsA treated animals confirmed that elongation was inhibited. These findings suggest that the in vivo administration of CsA results in the formation of a direct-acting inhibitor of renal translation rather than reducing translation by producing changes in renal transcription. The observation that renal translation is inhibited only after in vivo CsA suggests that a CsA metabolite formed in, or taken up by, the kidney produces translation inhibition, or that a cellular product involved in translation or translation regulation is formed or induced. We propose that the CsA induced inhibition of renal translation elongation accounts, at least in part, for CsA-induced nephrotoxicity.

接触性皮膚アレルギー反応に対する新しいシクロスポリン軟膏の有用性

A new cyclosporin A (CSA) ointment was prepared and its effect on contact skin reactions was evaluated in guinea pigs. 0.1% or 0.5% dinitrofluorobenzene (DNFB) -induced contact skin reactions were inhibited by twice daily topical application of 1-10% CSA ointment preparation, which showed more potency as compared to those of other topical CSA's or steroids. In contrast to oral administration of CSA (50 mg/kg) for 4 days, topical application over the same period resulted in more suppressive effect on contact skin reactions with rather lower CSA levels in blood (150 ng/ml) . CSA contents of this preparation were little changed even at 60°C for 3 months.These results indicate that this new CSA ointment is effective and stable preparation. Moreover, there would be a possibility that this preparation may be valuable in the treatment of human cutaneous immune-mediated disorders.

Hair Growth on Nude Mice Due to Cyclosporin A

One of the most common dermatological side effects of cyclosporin A (CsA) is dose-dependent hypertrichosis. Similar hair growth was noted in nude mice in an attempt to increase the acceptance of human xenografts with CsA in the T-cell-deficient congenitally athymic nude (nu/nu) mice. The aim of the present study was to further investigate the stimulation of hair growth on nude mice not only by oral administration of CsA but also by topical and subcutaneous administration of CsA. Young BALB/c female nude mice were treated for 3 or 4 weeks with topical, oral, or subcutaneous applications of CsA dissolved in olive oil at various doses. The hair of CsA-treated mice appeared to grow from 7 days after the treatment, even at low doses. Induced hair growth was dose-dependent and became clearly obvious 3 weeks after the treatment. The stimulation of hair growth was not restricted to the site of topical application. The distribution of the new hair depended on the natural pattern of hair growth in the mice. However, there was no hair growth in the control mice which were given only olive oil. Histological examination revealed that there were no differences in the structures of skin and hair between the control and the CsA-treated mice. Furthermore, the number of hair follicles did not remarkably increase after CsA treatment. The hair growth in the CsA-treated mice stopped after cessation of the treatment and returned to the level of the control mice on day 14 after the end of the treatment. Subsequent retreatment with CsA resulted in further regrowth of the hair.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in the venous compliance by bradykinin and angiotensin II and its significance for the vascular effects of cyclosporine-A.

Local infusion of both bradykinin and enalaprilic acid, the active metabolite of the converting enzyme inhibitor enalapril, elicited dose-dependent reduction of the compliance of the saphenous vein in conscious dogs. The competitive bradykinin B1-receptor antagonist, des-Arg9-Leu8-bradykinin antagonized venous responses to both bradykinin and enalaprilic acid effectively and with similar potency whereas the bradykinin B2-receptor antagonist Thi5,8,D-Phe7-bradykinin was about 100 times less potent when tested against bradykinin. Under control conditions local infusion of angiotensin II had no contractile activity but it elicited considerable venodilation after blockade of endogenous thromboxane A2 synthesis by dazoxiben. Blockade of the converting enzyme by enalapril (3 mg/kg i.v.) enhanced the maximal responses to bradykinin. Under these conditions concomitant local infusion of angiotensin II attenuated the venoconstrictor effects of bradykinin. Venous responses to bradykinin were inhibited after oral treatment of the dogs with the thromboxane A2 receptor antagonist BM 13,177 and nearly completely abolished after i.v. administration of the thromboxane synthesis inhibitor dazoxiben. In contrast, venous responses to enalaprilic acid were unchanged by thromboxane A2 receptor blockade and enhanced after dazoxiben. Following oral administration of cyclosporine-A (10 and 30 mg/kg), venous responses to bradykinin were attenuated while those to enalaprilic acid remained unchanged. Concomitant local infusion of the angiotensin II receptor antagonist saralasin (1 microgram/min) reversed completely the cyclosporine-A-induced reduction of the venoconstrictor effects of bradykinin.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporin A enhances the pulmonary granuloma response induced by Schistosoma mansoni eggs

The modulating effect of cyclosporin A (CsA) was studied in the immune-based pulmonary granuloma response to Schistosoma mansoni eggs. The extent of the S. mansori egg-induced inflammation was quantitated biochemically by measuring total units of N-acetyl-β-D-glucosaminidase (NAG) and total lung DNA. The enzyme NAG was used as a marker for the activity of inflammatory cells such as macrophages and DNA levels were used to quantify the increased cellularity of the lungs. In this model, the inflammatory response is maximal approximately 2 weeks after egg injection. Daily oral administration of CsA at 50 mg/kg during the first 2 weeks of the response dramatically enhanced the levels of pulmonary inflammation. Similar augmentation of the granuloma response was seen when CsA was given from days 0 to 7 but not when dosed from days 8 to 14. The enhancing effect of CsA was seen in the high-responder strains C57BL/10, B10.BR and CBA and in a lower-responder strain. Balb/c. Both the S. mansoni egg-induced granuloma response and the CsA-induced enhancement were dependent on functional T cells: athymic C57BL/6 nude (nu/nu) mice developed minimal responses to S. mansoni eggs which CsA did not augment, while heterozygous (nu/+) euthymic B6 mice responded to S. mansoni eggs and CsA. It appears in this model system that CsA may inhibit the activity of suppressor inducer or suppressor T cells. Cyclophosphamide, a drug know to reduce suppressor cell function, augmented the egg-induced inflammatory response similar to CsA. The enhancing activities of CsA and cyclophosphamide were not additive, suggesting effects on a common pathway of biologic activity, the generation of suppressor cells. While CsA and cyclophosphamide augmented the inflammatory process, conventional immunosuppressive drug therapies, dexamethasone and BW755c, quantifiably reduced the levels of NAG and DNA. These results demonstrate that CsA, rather than being immunosuppressive, augments this immune-based model of inflammation. In addition, this study shows that pulmonary granulomatous inflammation can be quantified biochemically with assays for both NAG and DNA.