Martin Caprnda

Inducible nitric oxide synthase: Good or bad?

Nitric oxide synthases (NOS) are a family of isoforms responsible for the synthesis of the potent dilator nitric oxide (NO). Expression of inducible NOS (iNOS) occurs in conditions of inflammation, and produces large amounts of NO. In pathological conditions iNOS is regarded as a harmful enzyme and is proposed to be a major contributor to diseases of the cardiovascular system such as atherosclerosis. In this review, we address the notion that iNOS is a detrimental enzyme in disease and discuss its potentially beneficial roles. Additionally, we describe other molecules associated with iNOS in diseases such as atherosclerosis, and current research on therapeutic inhibitors tested to reduced pathology associated with cardiovascular diseases (CVD).

Orthostatic hypotension in diabetic patients—10-year follow-up study

INTRODUCTION Cardiovascular autonomic neuropathy in diabetics is a common but often underestimated and underdiagnosed complication of diabetes mellitus. One of the most clinical apparent forms of cardiovascular autonomic neuropathy is orthostatic hypotension. OBJECTIVES To retrospectively assess the association of the orthostatic hypotension (OH) with macrovascular and microvascular complications of diabetes mellitus and to determine its effect on mortality. DESIGN AND METHODS We retrospectively analyzed 187 patients with diabetes mellitus (60 patients with diabetes type 1 and 127 patients with diabetes type 2). Patients were divided into groups according to presence or absence of OH and type of diabetes. Association of OH with macrovascular and microvascular complications was evaluated and the effect of OH on 10-year all-cause mortality was also assessed. RESULTS OH was present in 31.7% of patients with diabetes type 1 (DM1) and in 32.3% of patients with diabetes type 2 (DM2). OH was positively associated with the prevalence of myocardial infarction in DM1 (OR=10.67) and with prevalence of stroke in DM2 (OR=3.33). There was also a strong association of OH and the prevalence of peripheral artery disease in both DM1 (OR=14.18) and DM2 (OR=3.26). Patients with both types of diabetes and OH had significantly higher prevalence of nephropathy (DM1 OR=8.68, DM2 OR=3.24), retinopathy (DM1 OR=8.09, DM2 OR=4.08) and peripheral neuropathy (DM1 OR=17.14, DM2 OR=7.51) Overall 10year mortality rate was higher in diabetic patients with OH. CONCLUSIONS Presence of OH in diabetics is associated with higher prevalence of macrovascular and microvascular complications of diabetes mellitus and also with higher 10-year mortality.

Glucose Metabolism in Cancer and Ischemia: Possible Therapeutic Consequences of the Warburg Effect

ABSTRACT The Warburg effect states that the main source of energy for cancer cells is not aerobic respiration, but glycolysis—even in normoxia. The shift from one to the other is governed by mutually counteracting enzymes: pyruvate dehydrogenase and pyruvate dehydrogenase kinase (PDK). Anaerobic metabolism of cancer cells promotes cell proliferation, local tissue immunosuppression, resistance to hypoxic conditions, and metastatic processes. By switching glucose back to oxidative metabolism, these effects might be reversed. This can be achieved using PDK inhibitors, such as dichloroacetate. Patients suffering from ischemic conditions might benefit from this effect. On the other hand, the β-blockers (adrenergic β-antagonists) often used in these patients appear to improve cancer-specific survival, and nonselective β-blockers have been shown to promote glucose oxidation. Might there be a link?

Chili pepper as a body weight-loss food

Abstract Chili has culinary as well as medical importance. Studies in humans, using a wide range of doses of chili intake (varying from a single meal to a continuous uptake for up to 12 weeks), concluded that it facilitates weight loss. In regard to this, the main targets of chili are fat metabolism, energy expenditure, and thermogenesis. To induce weight loss, the active substance of chili, capsaicin, activates Transient Receptor Potential Cation Channel sub-family V member 1 (TRPV1) channels) receptors causing an increase in intracellular calcium levels and triggering the sympathetic nervous system. Apart from TRPV1, chili directly reduces energy expenditure by activating Brown Adipose Tissue. Weight loss by chili is also the result of an improved control of insulin, which supports weight management and has positive effects for treatment for diseases like obesity, diabetes and cardiovascular disorders. This review summarizes the major pathways by which chili contributes to ameliorating parameters that help weight management and how the consumption of chili can help in accelerating weight loss through dietary modifications.

Angiomodulators in cancer therapy: New perspectives

The formation of new blood vessels plays a crucial for the development and progression of pathophysiological changes associated with a variety of disorders, including carcinogenesis. Angiogenesis inhibitors (anti-angiogenics) are an important part of treatment for some types of cancer. Some natural products isolated from marine invertebrates have revealed antiangiogenic activities, which are diverse in structure and mechanisms of action. Many preclinical studies have generated new models for further modification and optimization of anti-angiogenic substances, and new information for mechanistic studies and new anti-cancer drug candidates for clinical practice. Moreover, in the last decade it has become apparent that galectins are important regulators of tumor angiogenesis, as well as microRNA. MicroRNAs have been validated to modulate endothelial cell migration or endothelial tube organization. In the present review we summarize the current knowledge regarding the role of marine-derived natural products, galectins and microRNAs in tumor angiogenesis.

Adipokines in neurovascular diseases

Adipose tissue is now described as an endocrine organ secreting a number of adipokines contributing to the development of inflammation and metabolic imbalance, but also endothelial dysfunction, vascular remodeling, atherosclerosis, and ischemic stroke. Leptin, adiponectin, and resistin are the most studied adipokines which play important roles in the regulation of cardiovascular homeostasis. Leptin and adiponectin mediate both proatherogenic and antiatherogenic responses. Leptin and adiponectin have been linked to the development of coronary heart disease and may be involved in the underlying biological mechanism of ischemic stroke. Resistin, a pro-inflammatory cytokine, is predictive of atherosclerosis and poor clinical outcomes in patients with coronary artery disease and ischemic stroke. The changes in serum levels of novel adipokines apelin, visfatin are also associated with acute ischemic stroke. These adipokines have been proposed as potential prognostic biomarkers of cardiovascular mortality/morbidity and therapeutic targets in patients with cardiometabolic diseases. In this article, we summarize the biologic role of the adipokines and discuss the link between dysfunctional adipose tissue and metabolic/inflammation imbalance, consequently endothelial damage, progression of atherosclerotic disease, and the occurrence of ischemic stroke.

Glycemic Variability and Vascular Complications in Patients with Type 2 Diabetes Mellitus

Abstract Background: Presence of macro- and microvascular complications in patients with diabetes mellitus (DM) is not only related to chronic hyperglycemia represented by glycated hemoglobin (HbA1c) but also to acute glycemic fluctuations (glycemic variability, GV). The association between GV and DM complications is not completely clear. Aim of our study was to evaluate GV by MAGE index in patients with type 2 DM and to verify association of MAGE index with presence of macro- and microvascular DM complications. Methods: 99 patients with type 2 DM were included in the study. Every patient had done big glycemic profile, from which MAGE index was calculated. Anthropometric measurements, evaluation of HbA1c and fasting plasma glucose (FPG) and assessment for macrovascular (coronary artery disease – CAD; peripheral artery disease – PAD; cerebral stroke – CS) and microvascular (diabetic retinopathy – DR; nephropathy – DN; peripheral neuropathy – DPPN) DM complications were done. Results: Average MAGE index value was 5.15 ± 2.88 mmol/l. We found no significant differences in MAGE index values in subgroups according to presence of neither CAD, CS, PAD nor DR, DN, DPPN. MAGE index value significantly positively correlated with FPG (p < 0.01) and HbA1c (p < 0.001) and negatively with weight (p < 0.05). Conclusion: In our study we failed to show association of MAGE index with presence of macrovascular and microvascular complications in patients with type 2 DM. However, this negative result does not necessarily disprove importance of glycemic variability in pathogenesis of diabetic complications.

Melatonin and breast cancer: Evidences from preclinical and human studies

The breast cancer affects women with high mortality and morbidity worldwide. The risk is highest in the most developed world but also is markedly rising in the developing countries. It is well documented that melatonin has a significant anti-tumor activities demonstrated on various cancer types in a plethora of preclinical studies. In breast cancer, melatonin is capable to disrupt estrogen-dependent cell signaling, resulting in a reduction of estrogen-stimulated cells, moreover, its obvious neuro-immunomodulatory effect in organism was described. Several prospective studies have demonstrated the inverse correlation between melatonin metabolites and the risk of breast cancer. This correlation was confirmed by observational studies that found lower melatonin levels in breast cancer patients. Moreover, clinical studies have showed that circadian disruption of melatonin synthesis, specifically night shift work, is linked to increased breast cancer risk. In this regard, proper light/dark exposure with more selective use of light at night along with oral supplementation of melatonin may have benefits for high-risk women. The results of current preclinical studies, the mechanism of action, and clinical efficacy of melatonin in breast cancer are reviewed in this paper. Melatonin alone or in combined administration seems to be appropriate drug for the treatment of early stages of breast cancer with documented low toxicity over a wide range of doses. These and other issues are also discussed.

Chemotherapeutic agents for the treatment of metastatic breast cancer: An update

Breast cancer is the second greatest cause of death among women worldwide; it comprises a group of heterogeneous diseases that evolves due to uncontrolled cellular growth and differentiation and the loss of normal programmed cell death. There are different molecular sub-types of breast cancer; therefore, various options are selected for treatment of different forms of metastatic breast cancer. However, the use of chemotherapeutic drugs is usually accompanied by deleterious side effects and the development of drug resistance when applied for a longer period. This review offers a classification of these chemotherapeutic agents according to their modes of action and therefore improves the understanding of molecular targets that are affected during treatment. Overall, it will allow the clinician to identify more specific targets to increase the effectiveness of a drug and to reduce general toxicity, resistance and other side effects.

Matrix metalloproteinase-3 gene polymorphism (rs3025058) affects markers atherosclerosis in type 2 diabetes mellitus

BACKGROUND The study was designed to test the possible association between either polymorphisms of the matrix metalloproteinase-9 (MMP-9) gene (rs17576, rs3918242) or the MMP-3 5A/6A gene polymorphism (rs3025058) with markers of carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM). The second aim of the study was to demonstrate an association between either the rs17576, rs3918242 or rs3025058 and subclinical markers of coronary artery disease in the same subset of patients with T2DM. PATIENTS AND METHODS A total of 595 subjects with T2DM and 200 subjects without T2DM (control group) were enrolled in the prospective study. Subclinical markers of carotid atherosclerosis were assessed ultrasonographically. Additionally, in a subset of subjects with T2DM a coronary computed tomography angiography (CCTA) was performed for diagnostic purposes. Genotyping of all three polymorphisms (rs17576, rs3918242, rs3025058) was performed with real-time PCR systems. RESULTS The comparison of atherosclerosis parameters was performed with regard to different genotypes of MMP-9 rs17576, rs3918242, and MMP-3 rs3025058 polymorphisms upon enrolment and during follow-up. In our study, we found an association between the MMP-3 rs3025058 and CIMT at the time of recruitment. Multiple linear regression analysis revealed the association of either the A- allele or the A- genotypes of the rs3025058 (MMP-3) with carotid intima media thickness (CIMT) progression in a 3.8-year follow-up. We demonstrated the effect of the rs3025058 on subclinical markers of coronary atherosclerosis (coronary calcium score, number of coronary arteries with more than 50 % stenosis, and presence of at least one vessel with more than 50 % stenosis). CONCLUSIONS We found an association between the MMP-3 rs3025058 and subclinical markers of carotid (CIMT) and coronary atherosclerosis at the time of recruitment. Moreover, we demonstrated the effect of the MMP-3 rs3025058 on CIMT progression in the 3.8-year follow-up in patients with T2DM.