May toxicity of amiodarone be prevented by antioxidants? A cell-culture study

Effect of adenosine triphosphate on amiodarone-induced optic neuropathy in rats: biochemical and histopathological evaluation

OBJECTIVE

This study aims to investigate possible preventive effect of ATP on optic nerve damage caused by amiodarone in rats.

MATERIAL AND METHOD

Thirty albino male Wistar rats weighing between 265 and 278 g were used in the study. Before the experiment, the rats were housed at 22 °C in a 12-h light/dark cycle under appropriate condition. The rats were equally divided into five groups of six animals each: healthy group, 50 mg/kg amiodarone (AMD-50), 100 mg/kg amiodarone (AMD-100), 25 mg/kg ATP + 50 mg/kg amiodarone (ATAD-50), and 25 mg/kg ATP + 100 mg/kg amiodarone (ATAD-100). At the end of 14th day, the animals were sacrificed using cardiac puncture under deep thiopental anaesthesia, and optic nerve tissues were harvested to measure superoxide dismutase (SOD), total glutathione (tGSH), malondialdehyde (MDA), and catalase (CAT) levels.

RESULTS

The MDA levels were found to be significantly higher in the AMD-50 and AMD-100 groups compared to the healthy group (p ˂ 0.001). There was also a significant difference between the AMD-50 and ATAD-50 groups, and between the AMD-100 and ATAD-100 groups regarding MDA levels (p ˂ 0.001). tGSH, SOD, and CAT levels were significantly lower in the AMD-50 and AMD-100 groups compared to the healthy group (p ˂ 0.001). ATP was found to partially inhibit amiodarone-induced optic neuropathy.

CONCLUSION

The biochemical and histopathological results of this study demonstrated that amiodarone at high doses caused more severe optic neuropathy inducing oxidative damage, but ATP could relatively antagonise these negative effects on the optic nerve. Therefore, we believe that ATP may be beneficial in preventing amiodarone-induced optic neuropathy.

The cytotoxic properties and apoptotic potential of N-butyl and 2-octyl cyanoacrylates used in surgical treatment of chronic venous insufficiency

Background

This study aims to investigate the cytotoxic effects and apoptotic potential of N-butyl cyanoacrylate and 2-octyl cyanoacrylate used in surgical treatment of chronic venous insufficiency.

Methods

N-butyl cyanoacrylate and 2-octyl cyanoacrylate were cultured in cell-culture using human umbilical endothelial cell-line. Cytotoxicity and viability were assessed at 24 and 72 hours with lactate dehydrogenase and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, respectively. Apoptotic potential was documented at 24 and 72 hours with relative caspase-3 activity.

Results

The mean cytotoxicity at 24 and 72 hours were: N-butyl cyanoacrylate with an area of dot/line: 37.0±3.9%/29.3±2.7% and 46.4±1.6%/45.1±7.1%, 2-octyl cyanoacrylate with an area of dot/line: 39.0±7.0%/37.3±4.6% and 47.0±2.3%/40.7±7.5%. Cytotoxicity increased by time in each group (p<0.05). The mean viability at 24 and 72 hours were: N-butyl cyanoacrylate with an area of dot/line: 53.4±7.7%/72.0±5.7% and 35.7±1.9%/37.8±3.7%, 2-octyl cyanoacrylate with an area of dot/line: 54.3±4.4%/73.5±19.9% and 33.6±2.8%/30.7±4.5%. The mean viability decreased by time in each group (p<0.05). The mean relative caspase-3 activity at 24 and 72 hours were: control group: 0.084±0.006 and 0.065±0.002, N-butyl cyanoacrylate with an area of dot/line: 0.940±0.037/0.924±0.053 and 0.999±0.072/1.056±0.015, 2-octyl cyanoacrylate with an area of dot/line: 0.900±0.044/0.928±0.018 and 0.989±0.084/0.999±0.072. The mean relative caspase-3 activity was higher than control group in each group at each time interval (p<0.05) and activity increased by time in N-butyl cyanoacrylate line and in 2-octyl cyanoacrylate line groups (p<0.05).

Conclusion

Our findings indicate that N-butyl cyanoacrylate and 2-octyl cyanoacrylate cause cytotoxicity in cell-culture media. We may also postulate that they induce apoptosis in cell-culture media.

Effects of N-acetyl cysteine, vitamin E and vitamin C on liver glutathione levels following amiodarone treatment in rats

Introduction

Amiodarone, a pharmaceutical extensively used to suppress atrial and ventricular tachyarrhythmias, is also known to cause many side effects on many tissues. N-acetyl-cysteine (NAC), vitamin E and vitamin C are known as antioxidants for their ability to minimize oxidative stress. In the peer-reviewed literature, there is no study reporting on the protective effects of these antioxidant agents against its hepatotoxicity.

Aim

We investigated the oxidative effects of NAC, vitamins E and C on liver tissue after amiodarone treatment.

Material and methods

Rats were randomly assigned to: control; amiodarone group; amiodarone + NAC treated group; amiodarone + Vit. E group and amiodarone + Vit. C group. Liver tissues were isolated from animals and total glutathione levels were measured.

Results

In all time intervals, the level of glutathione increased. When all time intervals were compared, the amiodarone group revealed the lowest levels. The antioxidant co-administered group was studied; the glutathione levels were statistically significantly higher than the sole amiodarone group. When vitamins E, C or N-acetyl cysteine were examined, there was no statistically significant difference among them.

Conclusions

In this study we found that hepatotoxicity capacity of amiodarone may be reduced by taking up antioxidants. In addition, the effect documented here may be reproducible and may be applied to clinical settings.

Emerging role of amiodarone and dronedarone, as antiarrhythmic drugs, in treatment of leishmaniasis

Leishmaniasis is a group of human and animal diseases causing 20,000-40,000 annual deaths and its etiological agents belong to the Leishmania genus. The most current treatment against leishmaniasis is chemotherapy. Pentavalent antimonials such as glucantime and pentostam have been administrated as the first-line drugs in treatment of various forms of leishmaniasis. The second-line drugs such as amphotericin B, liposomal amphotericin B, miltefosine, pentamidine, azole drugs and paromomycin are used in resistant cases to pentavalent antimonials. Because of drawbacks of the first-line and second-line drugs including adverse side effects on different organs, increasing resistance, high cost, need to hospitalization and long-term treatment, it is necessary to find an alternative drug for leishmaniasis treatment. Several investigations have reported the effectiveness of amiodarone, the most commonly used antiarrhythmic drug, against fungi, Trypanosomes and Leishmania spp. in vitro, in vivo and clinical conditions. Moreover, the beneficial effects of dronedarone, amiodarone analogues, against Trypanosoma cruzi and Leishmania mexicana have recently been demonstrated and such treatment regimens resulted in lower side effects. The anti- leishmanial and anti- trypanosomal effectiveness of amiodarone and dronedarone has been attributed to destabilization of intracellular Ca²⁺ homeostasis, inhibition of sterol biosynthesis and collapse of mitochondrial membrane potential. Because of relative low cost, excellent pharmacokinetic properties, easy accessibility and beneficial effects of amiodarone and dronedarone on leishmaniasis, they are proper candidates to replace the current drugs used in leishmaniasis treatment.

Involvement of oxidative stress and impaired lysosomal degradation in amiodarone-induced schwannopathy

Amiodarone hydrochloride (AMD), an anti-arrhythmic agent, has been shown to cause peripheral neuropathy; however, its pathogenesis remains unknown. We examined the toxic effects of AMD on an immortalized adult rat Schwann cell line, IFRS1, and cocultures of IFRS1 cells and adult rat dorsal root ganglion neurons or nerve growth factor-primed PC12 cells. Treatment with AMD (1, 5, and 10 μm) induced time- and dose-dependent cell death, accumulation of phospholipids and neutral lipids, upregulation of the expression of gangliosides, and oxidative stress (increased nuclear factor E2-related factor in nuclear extracts and reduced GSH/GSSG ratios) in IFRS1 cells. It also induced the upregulation of LC3-II and p62 expression, with phosphorylation of p62, suggesting that deficient autolysosomal degradation is involved in AMD-induced IFRS1 cell death. Furthermore, treatment of the cocultures with AMD induced detachment of IFRS1 cells from neurite networks in a time- and dose-dependent manner. These findings suggest that AMD-induced lysosomal storage accompanied by enhanced oxidative stress and impaired lysosomal degradation in Schwann cells might be a cause of demyelination in the peripheral nervous system.

N-acetylcysteine treats intravenous amiodarone induced liver injury

We report a case of intravenous (IV) amiodarone drug induced liver injury (DILI). The patient received IV N-acetylcysteine (NAC) which resulted in a rapid improvement in liver enzymes. While the specific mechanisms for the pathogenesis of IV amiodarone DILI and the therapeutic action of IV NAC are both unknown, this case strongly implies at least some commonality. Because IV amiodarone is indicated for the treatment of serious cardiac arrhythmias in an intensive care unit setting, some degree of ischemic hepatitis is likely a cofactor in most cases.

Heparin toxicity in cell culture: a critical link in translation of basic science to clinical practice

Heparin is a universal drug used frequently for its anticoagulant effects. The variabilities in distribution and tendency of heparin to accumulate in tissues cause increased tissue concentrations despite normal serum levels. We aimed to underline the toxic effects of heparin in cell culture make projections for clinical applications. L929 mouse fibroblastic cell line was plated in 96-well culture plates at an initial density of 5000 cells/well. Heparin was prepared in 10 different concentrations (10-300 units/well). Following 3 days of incubation, viabilities were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for each concentration in each day and compared. The viability of cells decreased significantly with increasing doses of heparin; at least 50 units/well in the first and second days and at least 20 units/well in the third day (P < 0.05 for each). There was statistically significant difference when the viabilities of cells treated with same heparin concentration in different days were compared (P < 0.05). The authors clearly demonstrated the toxic effects of heparin in cell culture, toxic effects increased as the dose increased. To prevent the unwanted clinical side-effects of heparin further studies should be made and more accurate testing methods should be developed to determine the effective tissue concentration of heparin.

Effect of Aronia melanocarpa fruit juice on amiodarone-induced pneumotoxicity in rats

Background:

The fruits of Aronia melanocarpa (Michx.) Elliot is extremely rich in biologically active polyphenols.

Objective:

We studied the protective effect of A. melanocarpa fruit juice (AMFJ) in a model of amiodarone (AD)-induced pneumotoxicity in rats.

Materials and Methods:

AD was instilled intratracheally on days 0 and 2 (6.25 mg/kg). AMFJ (5 mL/kg and 10 mL/kg) was given orally from day 1 to days 2, 4, 9, and 10 to rats, which were sacrificed respectively on days 3, 5, 10, and 28 when biochemical, cytological, and immunological assays were performed.

Results:

AMFJ antagonized AD-induced increase of the lung weight coefficient. In bronchoalveolar lavage fluid, AD increased significantly the protein content, total cell count, polymorphonuclear cells, lymphocytes and the activity of lactate dehydrogenase, acid phosphatase and alkaline phosphatase on days 3 and 5. In AMFJ-treated rats these indices of direct toxic damage did not differ significantly from the control values. In lung tissue, AD induced oxidative stress measured by malondialdehyde content and fibrosis assessed by the hydroxyproline level. AMFJ prevented these effects of AD. In rat serum, AD caused a significant elevation of interleukin IL-6 on days 3 and 5, and a decrease of IL-10 on day 3. In AMFJ-treated rats, these indices of inflammation had values that did not differ significantly from the control ones.

Conclusion:

AMFJ could have a protective effect against AD-induced pulmonary toxicity as evidenced by the reduced signs of AD-induced direct toxic damage, oxidative stress, inflammation, and fibrosis.

Prevention of amiodarone-induced cardiac toxicity in male BALB/c mice by a nutrient mixture

Amiodarone (Amio), a potent anti-arrhythmic drug, is associated with life-threatening pulmonary toxicity involving fibroses and inflammation. A unique nutrient mixture (NM) consisting of lysine, proline, ascorbic acid, N-acetyl cysteine and green tea extract has previously been shown to exhibit a broad spectrum of pharmacological, therapeutic, cardiovascular and chemopreventive properties. The present study was undertaken to determine whether the NM exhibits preventive effects on Amio-induced cardiac toxicity. Six-week-old male BALB/c mice were divided into four groups (A–D) of six animals per group. Mice in groups A and C were fed a regular diet for three weeks, while the diets of the mice in groups B and D were supplemented with 1% NM during that period. After three weeks, the mice in groups C and D received daily Amio injections of 50 mg/kg body weight intraperitoneally for 4 days, whilst those in groups A and B received saline alone. At 24 h after the final dose, mice were sacrificed, blood was withdrawn and serum was collected for clinical chemistry of the heart enzymes creatine phosphokinase (CPK) and aspartate aminotransferase (AST). In addition, livers, kidneys, hearts and lungs were excised and weighed. No significant differences in weight gain were identified among the groups and liver, kidney, heart and lung weights were comparable in all four groups. Administration of Amio to group C resulted in a significant increase in serum CPK levels, whereas in NM-fed group D, the CPK levels were comparable to those in the saline injection groups, A and B. Amio administration also resulted in a significant increase in serum AST levels in group C, but not in the group D animals which exhibited similar levels to those of groups A and B. Therefore, the results indicate that NM has the potential to protect against Amio-induced cardiac toxicity.