Peter Kružliak

Vascular endothelial growth factor inhibitor-induced hypertension: from pathophysiology to prevention and treatment based on long-acting nitric oxide donors.

Hypertension is the most common adverse effect of the inhibitors of vascular endothelial growth factor (VEGF) pathway-based therapy (VEGF pathway inhibitors therapy, VPI therapy) in cancer patients. VPI includes monoclonal antibodies against VEGF, tyrosine kinase inhibitors, VEGF Traps, and so-called aptamers that may become clinically relevant in the future. All of these substances inhibit the VEGF pathway, which in turn causes a decrease in nitric oxide (NO) and an increase in blood pressure, with the consequent development of hypertension and its final events (e.g., myocardial infarction or stroke). To our knowledge, there is no current study on how to provide an optimal therapy for patients on VPI therapy with hypertension. This review summarizes the roles of VEGF and NO in vessel biology, provides an overview of VPI agents, and suggests a potential treatment procedure for patients with VPI-induced hypertension.

MicroRNA-206: a Promising Theranostic Marker

MicroRNAs (miRs) are small non-coding RNAs that negatively regulate gene expression by binding to the 3` untranslated regions (3`UTR) of their target mRNAs. MiRs were shown to play pivotal roles in tissue development and function and are also involved in the pathogenesis of various diseases including cancer. MicroRNA-206, which belongs to the group of so-called “myomiRs”, is one of the most studied miRs thus far. In addition to being involved in skeletal muscle development and pathology, it has also been established that it is involved in the pathogenesis of numerous diseases including heart failure, chronic obstructive pulmonary disease, Alzheimers disease and various types of cancers. The aim of this review is to provide a complex overview of microRNA-206, including regulating its expression, a brief description of its known functions in skeletal muscle and a complex overview of its roles in the biology and pathology of other tissues, emphasizing its significant diagnostic and therapeutic potential.

Melatonin potentiates the anti-tumour effect of pravastatin in rat mammary gland carcinoma model

Previous studies in the field of cancer research have suggested a possible role for statins in the reduction of risk in certain malignancies. The purpose of these studies was to examine the chemopreventive effects of pravastatin alone and in combination with pineal hormone melatonin in the N‐methyl‐N‐nitrosourea‐induced mammary carcinogenesis model. Pravastatin was given orally (1 00 mg/kg) and melatonin was added to the water (20 μg/ml). Chemoprevention began seven days prior to carcinogen administration and subsequently continued for 15 weeks until autopsy. At autopsy, mammary tumours were removed and prepared for histopathological and immunohistochemical analysis. Parameters of experimental carcinogenesis, mechanism of action (biomarkers of apoptosis, angiogenesis and proliferation) and side effects after long‐term treatment in animals were assessed. Pravastatin alone suppressed tumour frequency by 20.5% and average tumour volume by 15% compared with controls. Combined administration of the drugs decreased tumour frequency by 69% and lengthened tumour latency by nine days compared with control animals. The ration between high and low grade carcinomas was apparently reduced in both treated groups. The analysis of carcinoma cells showed significant expression increase in caspase‐3 and caspase‐7 after pravastatin treatment; however, combined treatment even more pronounced increase in the expression of both caspases. Regarding VEGFR‐2 expression, a small effect in carcinomas of both treated groups was found. In plasma metabolism evaluation, pravastatin alone significantly decreased levels of glucose and triacylglycerols. Our results suggest a mild anti‐neoplastic effect of pravastatin in this rat mammary gland carcinoma model. Statins co‐administered with other suitable drug (e.g. melatonin) should be further evaluated for tumour‐preventive properties.

Hepatitis B virus infection in patients with metabolic syndrome: A complicated relationship. Results of a population based study

BACKGROUND The presence of hepatitis B infection (HBI) and metabolic syndrome (MS) at the same time constitutes a high risk for liver cirrhosis and potentially hepatocellular carcinoma. AIM In this study we aim to explore the relationship between MS and HBI. METHODS We used data from the cross-sectional HepaMeta study conducted in 2011 in Slovakia. Patients were tested for presence of MS, while lipid levels (total cholesterol, HDL, LDL, TG, apolipoprotein B100 and HBI (HBsAg and antiHBcIgG)) were also monitored. Viral load was measured in HBsAg positive patients. RESULTS Altogether 855 patients were screened, MS was diagnosed in 25.1% of patients and 7.9% of patients presented with HBI. AntiHBcIgG antibodies were present in 34.6% patients. HBI patients had lower levels of total and LDL cholesterol along with a decreased apolipoprotein B100 (4.54 ± 0.84 vs. 5.0 ± 0.99 mmol/l, P=0.001; 2.29 ± 0.58 vs. 2.6 ± 0.68 mmol/l, P=0.001 and 0.71 ± 0.21 vs. 0.77 ± 0.23 mmol/l, P=0.013 respectively). Patients diagnosed with MS had higher HBV DNA load than patients without MS - 1300.2 (95% CI 506.06-3440.41) vs. 7661.3 (95% CI 2008.17-29,228.06) IU/ml; P=0.011. HBI patients with TC and apolipoprotein B100 in the reference range had lower HBV DNA load than patients with high or low values of TC or apolipoprotein B100. CONCLUSION Hepatitis B patients had lower levels of total and LDL cholesterol along with a decreased apolipoprotein B100. Viral load of chronic hepatitis B patients with MS was higher than that in patients without MS.

The effects of two Lactobacillus plantarum strains on rat lipid metabolism receiving a high fat diet.

The aim of our study was to evaluate the effects of the different probiotic strains, Lactobacillus plantarum LS/07 and Lactobacillus plantarum Biocenol LP96, on lipid metabolism and body weight in rats fed a high fat diet. Compared with the high fat diet group, the results showed that Lactobacillus plantarum LS/07 reduced serum cholesterol and LDL cholesterol, but Lactobacillus plantarum Biocenol LP96 decreased triglycerides and VLDL, while there was no change in the serum HDL level and liver lipids. Both probiotic strains lowered total bile acids in serum. Our strains have no significant change in body weight, gain weight, and body fat. These findings indicate that the effect of lactobacilli on lipid metabolism may differ among strains and that the Lactobacillus plantarum LS/07 and Lactobacillus plantarum Biocenol LP96 can be used to improve lipid profile and can contribute to a healthier bowel microbial balance.

Combination of Pitavastatin and melatonin shows partial antineoplastic effects in a rat breast carcinoma model.

Our previous results indicated significant tumor-suppressive effects of different statins in rat mammary carcinogenesis. The purpose of this experiment was to examine the chemopreventive effects of Pitavastatin alone and in combination with the pineal hormone melatonin in the model of N-methyl-N-nitrosourea-induced mammary carcinogenesis in female Sprague-Dawley rats. Pitavastatin was administered dietary (10mg/kg) and melatonin in an aqueous solution (20μg/ml). Chemoprevention began 7 days prior to carcinogen administration and subsequently continued for 15 weeks until autopsy. At autopsy, mammary tumors were removed and prepared for histopathological and immunohistochemical analysis. Compared to controls, Pitavastatin alone reduced average tumor volume by 58% and lengthened latency by 8 days; on the other hand, the drug increased tumor frequency by 23%. Combined administration of Pitavastatin with melatonin decreased tumor frequency by 23%, tumor volume by 44% and lengthened tumor latency by 5.5 days compared to control animals. The analysis of carcinoma cells showed significant increase in caspase-3 expression in both treated groups and a tendency of increased caspase-7 expression after Pitavastatin treatment alone. Significant expression decrease of Ki67 was found in carcinoma cells from both treated groups. Compared to control carcinoma cells, Pitavastatin alone increased VEGF expression by 41%, however melatonin totally reversed its undesirable effect. Pitavastatin combined with melatonin significantly increased femur compact bone thickness in animals. Pitavastatin alone decreased plasma triglycerides and total cholesterol levels, however it significantly increased levels of glucose. In summary, our results show a partial antineoplastic effect of Pitavastatin combined with melatonin in the rat mammary gland carcinoma model.

Relationship of mismatch repair proteins and survivin in colon polyps and carcinomas.

Mismatch repair genes (MMR) play an essential role in DNA repair. MMR mutations predominantly in MLH1, MSH2, MSH6, PMS2, and rarely in PMS1, may cause the production of abnormally short or inactivated proteins. The antiapoptotic protein survivin functions in the inhibition of apoptosis, regulation of cell division and also enhances angiogenesis. Both MMRP and survivin are considered to be powerful prognostic parameters. This study was designed to determine the relationship between MMRP and survivin in colon lesions. The study included 113 cases of colon carcinoma and 51 cases of colon polyps. Survivin expression and MMRP status were assessed by immunohistochemistry. In each section, expression, intensity of immunostaining and percentage of labeled cells were analyzed. In carcinomas, immunoreaction was detected in 100/113 cases for MLH1 (88.5%), 112/113 cases for MSH2 (99.1%), 110/113 cases for MSH6 (97.3%), and 103/113 cases for PMS2 (91.2%). Survivin was shown in 47/113 cases (41.6%). The statistical analysis confirmed a significant correlation between the expression of MMRP and survivin in the assessed parameters. All 51 polyp samples were positive for MLH1, MSH2, MSH6 and PMS2. Only 8 of those (15.7%) were positive for survivin. Statistically significant differences were observed between the expression of MMRP and survivin. In conclusion, this study revealed that MMRP may suppress the antiapoptotic function of survivin through p53 inactivation of its promoter in grade 1 and grade 2 colon carcinomas.

Role of high-fat diet on the effect of pioglitazone and melatonin in a rat model of breast cancer.

The risk of cancer may be modulated by drugs with pleiotropic effects and diet has been implicated in the efficacy of treatment. The oncopreventive effects of the antidiabetic drug pioglitazone (PIO) and the anti-insomnia drug melatonin (MT), in vivo, have been proven before, but using a standard-type diet. This study evaluated the impact of a high-fat diet on their efficacy in chemically induced mammary carcinogenesis in Sprague–Dawley rats. Mammary tumours were induced by N-methyl-N-nitrosourea (50 mg/kg, intraperitoneal, on the 41st postnatal day). PIO and MT administration was initiated 11 days before the carcinogen application and lasted until the termination of the experiment at 16 weeks. PIO was administered in a diet (10% fat) at a concentration of 100 ppm and MT was administered in tap water (20 mg/l). PIO, MT and the combination did not significantly alter the basic tumour growth parameters. However, histopathology showed a decrease in the high-grade/low-grade tumour ratio, particularly in animals that received combined treatment (P<0.01). Semiquantitative immunohistochemistry indicated the proapoptotic effect of chemoprevention, particularly in the drug combination group (P<0.01), but no changes in tumour cell proliferation and angiogenesis were recorded. Results were evaluated by one-way analysis of variance or the Mann–Whitney U-test, respectively. PIO and MT, alone or in combination, administered to rats fed a high-fat diet reduced the proportion of high-grade tumours and promoted apoptosis in an in-vivo breast cancer model, although it did not suppress tumour growth. The impact of high dietary fat content on the chemopreventive efficacy of these and other substances should be considered in human studies.

Chlorella pyrenoidosa, young barley and fruit peel polyphenols in rat breast cancer model – the effects on plasma lipid metabolism

Abstract On the basis of several preclinical and clinical studies, we have assumed that phytochemicals may play an important role in plasma lipid metabolism. The aim of this study was to evaluate the effects of dietary administered Chlorella pyrenoidosa, young barley and fruit peel polyphenols from Flavin7 on plasma lipid metabolism in breast cancer model in female rats. The phytopharmaceuticals were dietary administered at two different concentrations (0.3% and 3%). The administration of drugs lasted for the whole duration of the experiment (14-15 weeks) until autopsy. At the end of the experiments blood was collected from animals and serum lipid parameters were evaluated. Flavin7 in lower dose significantly decreased LDL-cholesterol and in higher dose significantly decreased triacylglycerol and VLDL-cholesterol levels. Chlorella at the higher dose significantly decreased LDL- and VLDL-cholesterol and triacylglycerol levels. Young barley significantly decreased LDL cholesterol (at the higher dose); on the other hand, a tendency of increased serum triacylglycerol and VLDLcholesterol levels was found (in both doses). Our results pointed to significant beneficial effects of fruit peel polyphenols from Flavin7 and C. pyrenoidosa on plasma lipid metabolism in female rats. Further research is needed to elucidate the health benefits of phytochemicals in whole foods.