Chemosensetizing and cardioprotective effects of resveratrol in doxorubicin- treated animals.

BACKGROUND: Doxorubicin (DOX), an anthracycline antibiotic is one of the most effective anticancer drug used in the treatment of variety of cancers .Its use is limited by its cardiotoxicity. The present study was designed to assess the role of a natural product resveratrol (RSVL) on sensitization of mammary carcinoma (Ehrlich ascites carcinoma) to the action of DOX and at the same time its protective effect against DOX-induced cardiotoxicity in rats. METHODS: Ehrlich ascites carcinoma bearing mice were used in this study. Percent survival of tumor bearing mice was used for determination of the Cytotoxic activity of DOX in presence and absence of RSVL. Uptake and cell cycle effect of DOX in tumor cells in the presence of RSVL was also determined. Histopatholgical examination of heart tissues after DOX and/or RSVL therapy was also investigated. RESULTS: DOX at a dose level of 15 mg/kg increased the mean survival time of tumor bearing mice to 21 days compared with 15 days for non tumor-bearing control mice. Administration of RSVL at a dose level of 10 mg/kg simultaneously with DOX increased the mean survival time to 30 days with 70% survival of the tumor-bearing animals. RSVL increased the intracellular level of DOX and there was a strong correlation between the high cellular level of DOX and its cytotoxic activity. Moreover, RSVL treatment showed 4.8 fold inhibition in proliferation index of cells treated with DOX. Histopathological analysis of rat heart tissue after a single dose of DOX (20 mg/kg) showed myocytolysis with congestion of blood vessels, cytoplasmic vacuolization and fragmentation. Concomitant treatment with RSVL, fragmentation of the muscle fiber revealed normal muscle fiber. CONCLUSION: This study suggests that RSVL could increase the cytotoxic activity of DOX and at the same time protect against its cardiotoxicity.

Characterization and optimization of lyophilization and storage conditions of Leech saliva extract from the tropical leech Hirudinaria manillensis.

The medicinal Malaysian leeches have been used in traditional medicine to treat many different ailments. In this study, leech saliva extract (LSE) was collected from the medicinal Malaysian leech Hirudinaria manillensis. Gel electrophoresis of LSE was carried out to estimate the peptide and protein molecular weights of its content. Results showed that LSE contains more than 60 peptides and proteins with molecular masses ranging from 1.9-250kDa. Thrombin time assay in vitro was employed to assess the collected LSE antithrombin activity. First, to study its stability, LSE was lyophilized under the following different conditions: pre-freezing temperature, type of container and lyophilization cycle. Pre-freezed LSE sample at -20°C and lyophilized for 24 hours retained about 100-95% of its original biological activities. Second, the LSE antithrombin activity was monitored for a period of six months. Storage temperature, type of the container and photosensitivity effects on antithrombin activity of the lyophilized (solid state) and non-lyophilized (liquid state) were investigated. Results showed that storage temperature drastically affected the biological activity of LSE with -20 °C as the optimum temperature. Samples stored at ambient temperature and +4 °C were light photosensitive and adversely affected when stored in polypropylene tubes. Lyophilized samples were more stable than non-lyophilized ones over the period of study. To sum up, in order to have a biologically active stock of LSE, it has to be lyophilized for no more than 24 hours following freezing at -20°C and has to be stored at -20°C in glass tubes protected from light.

Association of cytochromes P450 3A4*22 and 3A5*3 genotypes and polymorphism with response to simvastatin in hypercholesterolemia patients.

BACKGROUNDS: Inter-individual variability in response to statin was mainly due to genetic differences. This study aimed to investigate the association of CYP3A4*22 (rs35599367), CYP3A5*3 (rs776746) single nucleotide polymorphism (SNP) with response to simvastatin in hypercholesterolemia patients conducted at King Abdulaziz University hospital (KAUH) in Jeddah, Saudi Arabia. PATIENTS AND METHODS: A total of 274 participants were registered in the current study. Hypercholesterolemic patients taking simvastatin 20 mg (n = 148) and control subjects (n = 126) were tested for rs35599367 and rs776746 genotypes using Custom Taqman ® Assay Probes. Response to simvastatin in these patients was assessed by determination of low density lipoprotein (LDL-C), total cholesterol (TC) and by measuring statin plasma levels using Liquid Chromatography-Mass Spectrometry (LC-MS). RESULTS: None of the participants carried a homozygous CYP3A4*22 mutant genotype, while 12 (4.4%) individuals had a heterozygous genotype and 262 (95.6%) had a wild homozygous genotype. The CYP3A5*3 allele was detected in the homozygous mutant form in 16 (5.8%) individuals, while 74 (27.0%) individuals carried the heterozygous genotype and 184 (67.2%) carried the wildtype homozygous genotype. Of the patient group, 15 (11%) were classified as intermediate metabolizers (IMs) and 133 (89%) as extensive metabolizers (EMs). Plasma simvastatin concentrations for the combined CYP3A4/5 genotypes were significantly (P<0.05) higher in the IMs group than in the EMs group. TC and plasma LDL-C levels were also significantly (P<0.05) higher in IMs than in EMs. CONCLUSION: The present study showed associations between CYP3A4*22 (rs35599367) and CYP3A5*3 (rs776746) SNP combination genotypes with response to statins in hypercholesterolemia. Patients who had either a mutant homozygous allele for CYP3A5*3 or mutant homozygous and heterozygous alleles for CYP3A4*22 showed increased response to lower TC and LDL-C levels.

Amelioration of doxorubicin­induced cardiotoxicity by resveratrol.

Doxorubicin (DOX), is a highly active anticancer agent, but its clinical use is limited by its severe cardiotoxic side­effects associated with increased oxidative stress and apoptosis. Resveratrol (RSVL) is a naturally occurring polyphenolic compound (trans-3,5,4'-trihydroxystilbene) found primarily in root extracts of the oriental plant Polygonum cuspidatum and of numerous additional plant species. It has recently been shown that RSVL has a number of beneficial effects in different biological systems, which include anti-oxidant, antineoplastic, anticarcinogenic, cardioprotective and antiviral effects. In this study, we examined whether RSVL has protective effects against DOX­induced free radical production and cardiotoxicity in male rats. The tested dose of DOX (20 mg/kg) caused a significant increase in the serum activities of the cardiac enzymes lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) and the level of malondialdehyde (MDA) in the heart tissue. However, there was a significant decrease in the glutathione level in the heart tissue. Simultaneous treatment of rats with RSVL [10 mg/kg, intraperitoneal (i.p.) injection] reduced the activity of LDH and CPK and significantly reduced MDA production in the heart. The total antioxidant capacity was increased following RSVL administration. Electron microscopy examination of the heart tissue showed that DOX treatment results in massive fragmentation and lysis of the myofibrils, and that mitochondria show either vacuolization or complete loss of the cristae. Simultaneous treatment with RSVL ameliorated the effect of DOX administration on cardiac tissue, with cardiomyocytes appearing normal compared to the control samples, and mitochondria retaining their normal structure.