Abnormalities in the relationship of paraoxonase 1 with HDL and apolipoprotein A1 and their possible connection to HDL dysfunctionality in type 2 diabetes.

AIMS: Lipid parameters, lipid risk indexes and lipid-related oxidative stress markers (paraoxonase 1 [PON1] and lipid peroxides [LPO]) reflect the actual status of lipid metabolism in type 2 diabetes (T2DM). We hypothesized that relationships of high-density lipoprotein cholesterol (HDL-c) with PON1 and apolipoprotein A1 (ApoA1) and/or PON1 with ApoA1 under conditions of hyperglycaemia and oxidative stress might reveal HDL functionality. We investigated relationships between PON1, LPO, and lipid risk markers in T2DM subjects and compared them with those in healthy subjects. METHODS: A total of 107 Caucasian subjects, 67 T2DM outpatients (mean age 52.2 ±â€¯6.9 years) and 40 healthy subjects (mean age 48.1 ±â€¯7.5 years) were included in the study. Serum levels of total cholesterol (CHOL-T), HDL-c, low-density lipoprotein cholesterol (LDL-c), triglycerides (TG), apolipoprotein B (ApoB), ApoA1, LPO, and PON1 activity were measured. Non-HDL-c, ApoB/ApoA1 and non-HDL/HDL (lipid risk indexes) were calculated. RESULTS: Higher levels of TG, LPO (P < 0.0001), nonHDL/HDL and ApoB/ApoA1 (P < 0.001, 0.05, respectively), and lower levels of HDL-c, ApoA1, and PON1 (P < 0.0001) were observed in T2DM subjects than in controls. There is a lack of relationship among PON1, HDL-c, and ApoA1 in T2DM patients. PON1 activity positively correlated with these parameters (P < 0.0001) in controls. Strong correlations between non-HDL-c and ApoB (r = 0.956 vs. 0.756; P < 0.0001), LPO and TG (r = 0.831 vs. 0.739; P < 0.0001) were recorded in both study groups (P < 0.0001). CONCLUSIONS: Impaired anti-oxidant and anti-atherogenic HDL properties associated with weakened PON1 function and lipid peroxidation may contribute to the development of atherosclerosis-related diseases in T2DM.

Antioxidant vitamins prevent oxidative and carbonyl stress in an animal model of obstructive sleep apnea.

PURPOSE: The aim of our study was to analyze the effects of an antioxidant treatment on markers of oxidative and carbonyl stress in a rat model of obstructive sleep apnea. METHODS: Wistar rats were randomized into six groups-according to gender and intervention-sham, intermittent hypoxia, and intermittent hypoxia with treatment by vitamins C and E. Rats underwent tracheostomy. The tracheal cannula was closed for 12 s every minute for 1 h to simulate obstructive sleep apnea-related intermittent hypoxia. In the treatment group, rats received vitamin C and E 24 h prior to surgery. RESULTS: The intervention had a significant effect on advanced oxidation protein products (p = 0.008) and advanced glycation end products-specific fluorescence (p = 0.006) but no effect on malondialdehyde. Oxidation and glycation protein products were higher in intermittent hypoxia groups than in sham and in treated groups. CONCLUSIONS: Antioxidants alleviate oxidative and carbonyl stress in an experimental model of obstructive sleep apnea. Future studies will show whether such treatment has any clinical value regarding cardiovascular complications of sleep apnea syndrome, preferably in patients with low compliance to continuous positive airway pressure.

The use of transformed Escherichia coli for experimental angiogenesis induced by regulated in situ production of vascular endothelial growth factor--an alternative gene therapy.

BACKGROUND: Defects in angiogenesis (blood vessel formation) are responsible for two most important causes of death in developed countries (ischemic heart disease and cancer). Vascular endothelial growth factor (VEGF) plays a pivotal role in physiological and pathological regulation of angiogenesis. In the last years several studies have indicated the possibilities of VEGF in the therapy of ischemic heart disease. However, especially VEGF gene therapy (naked DNA, plasmids and adenovirus mediated) is associated with adverse side effects regarding the expression regulation. AIM: To prepare bacterial strains producing VEGF using plasmids containing the VEGF cDNA for the use in experimental angiogenesis. METHODS AND RESULTS: Escherichia coli strain BL21(DE3) was transformed with Bluescript vector containing the inserts with cDNA sequences coding VEGF-A isoforms (VEGF121, VEGF164, VEGF189). Selection of recombinants was achieved by cultivating E. coli cells on ampicillin-added medium. The expression of target genes in the T7 expression system was induced by isopropyl-beta-D-thiogalactoside (IPTG). Polyacrylamide gel electrophoresis of the cell lysates showed the presence of polypeptides of molecular weight corresponding with known values of VEGF isoforms. Blood vessel formation induced by bacterial VEGF production was proved in vivo in mice seven days after intraperitoneal injection of transformed bacteria by light microscopy. CONCLUSION AND HYPOTHESIS: In summary, E. coli strain expressing VEGF was prepared and its biological effect confirmed. Bacteria, which produce angiogenic factors, provide a new modality for experimental angiogenesis and may be also suitable for clinical use. The in situ production of therapeutic proteins using optimalized prokaryotic expression systems can represent a useful tool for treatment based on molecular biomedicine. The main advantage of the described approach lies in the enhanced regulation control--bacterial expression can be regulated positively (induction by exogenous low molecular weight agents) and negatively (application of antibiotics). The hypothesis of alternative gene therapy should be proved in further studies.

Sleep apnea syndrome and its complications.

In this article we summarize the available information regarding the epidemiology, the pathophysiology as well as the risk factors and complications of the sleep apnea syndrome (SAS). Central, obstructive and mixed forms of SAS are known, however, the obstructive form is (resulting from the actual high prevalence of obesity) definitely the most frequent. Latest years of experimental and clinical research have pointed towards the clinical importance of this sleep related breathing disorder. High prevalence in the population and especially the cardiovascular complications (e. g. systemic and pulmonary hypertension, atherosclerosis, arrhythmias) have contributed to the recent increase in knowledge about SAS. Nevertheless, there are numerous unsolved problems and unanswered questions in the pathophysiology of SAS. Future studies should, thus, provide us with more information and shed light on regarding the hidden mysteries of SAS.

Effects of anabolic steroids and antioxidant vitamins on ethanol-induced tissue injury.

Various mechanisms are involved in the process of ethanol-induced tissue impairment. Oxidative stress and its effects are among the most important. We compared the effects of antioxidant vitamins (vitamin C and E in combination) and steroids (testosterone and nandrolone separately) on the toxicity of ethanol in rats. Animals (male Wistar rats, n = 48) were randomised into following groups-Control, Ethanol, Testosterone, Ethanol + Testosterone, Ethanol + Nandrolone, Ethanol + Vitamins. Alcohol was given daily by gavage in a dose of 5 g/kg of body weight. On the 27th day of the study the animals were sacrificed by decapitation and tissue samples were taken. Metabolic status, parameters of the hepatic metabolism, hormone levels (testosterone, ACTH, corticosterone), lipoperoxidation markers (malondialdehyde and conjugated diens in forebrain cortex and in cerebellum) and advanced glycation end-products were analysed. Tissue samples underwent histological examination. Histological outcomes showed a protective effect of antioxidants on hepatic and cerebellar injury caused by chronic ethanol intake. Anabolic steroids protected especially the central nervous tissue against the toxicity of alcohol. Both, antioxidant vitamins and anabolic steroids protect against the ethanol-induced toxicity, however, this effect is tissue specific.