Percutaneous Closure of Left Atrial Appendage significantly affects Lipidome Metabolism

Patients with non-valvular atrial fibrillation (AF) and a high risk for oral anticoagulation can be treated by percutaneous implantation of left atrial appendage occlusion devices (LAAC) to reduce the risk of cardio-embolic stroke. This study evaluates whether LAAC may influence lipid metabolism, which has never been investigated before. Patients with successful LAAC were included consecutively. Venous peripheral blood samples of patients were collected immediately before (T0, baseline) and 6 months after (T1, mid-term) LAAC. A targeted metabolomics approach based on electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS/MS) and MS/MS measurements was performed. A total of 34 lipids revealed a significant change from baseline to mid-term follow-up after successful LAAC. Subgroup analysis revealed confounding influence by gender, age, diabetes mellitus type II, body mass index, left ventricular ejection fraction, creatinine and NT-proBNP. After multivariable adjustment within logistic regression models, these 34 lipids were still significantly altered after LAAC. Successful percutaneous LAAC may affect lipid metabolism and thereby may potentially affect pro-atherogenic and cardio-toxic effects.

Correction to: Occlusion of left atrial appendage affects metabolomic profile: focus on glycolysis, tricarboxylic acid and urea metabolism

The article Occlusion of left atrial appendage aff ects metabolomic profile:focus on glycolysis, tricarboxylic acid and urea metabolism, written by K. Sattler, M. Behnes, C. Barth, A. Wenke, B. Sartorius, I. El-Battrawy, K. Mashayekhi, J. Kuschyk, U. Hoffmann, T. Papavasiliu, C. Fastner, S. Baumann, S. Lang, X. Zhou, G. Yücel, M. BorggrefeI, Akin, was originally published Online First without open access.

Occlusion of left atrial appendage affects metabolomic profile: focus on glycolysis, tricarboxylic acid and urea metabolism

BACKGROUND

Left atrial appendage (LAA) closure (LAAC) by implantation of an occlusion device is an established cardiac intervention to reduce risk of stroke while avoiding intake of oral anticoagulation medication during atrial fibrillation. Cardiac interventions can alter local or systemic gene and protein expression. Effects of LAAC on systemic metabolism have not been studied yet.

OBJECTIVES

We aimed to study the effects of interventional LAAC on systemic metabolism.

METHODS

Products of glycolysis, tricarboxylic acid and urea metabolism were analyzed by ESI-LC-MS/MS and MS/MS using the AbsoluteIDQ™ p180 Kit in plasma of 44 patients undergoing successful interventional LAAC at baseline (T0) and after 6 months (T1).

RESULTS

During follow up, plasma concentrations of several parameters of glycolysis and tricarboxylic acid cycle (TCA) and urea metabolism increased (alanine, hexose, proline, sarcosine), while others decreased (aspartate, glycine, SDMA, serine). Multivariate linear regression analysis showed that time after interventional LAAC was an independent predictor for metabolite changes, including the decrease of SDMA (beta -0.19, p < 0.01) and the increase of sarcosine (beta 0.16, p < 0.01).

CONCLUSIONS

Successful interventional LAAC affects different pathways of the metabolome, which are probably related to cardiac remodeling. The underlying mechanisms as well as the long term effects have to be studied in the future.

LC-MS/MS analysis of plasma polyunsaturated fatty acids in type 2 diabetic patients after insulin analog initiation therapy

Background

Eicosanoids derived from omega-6 (n6) polyunsaturated fatty acids (PUFAs) have proinflammatory functions whereas eicosanoids derived from omega-3 (n3) PUFAs have anti-inflammatory properties. This study was designed to evaluate the effect of insulin analog initiation therapy on n6 and n3 PUFAs in type 2 diabetic patients during early phase.

Methods

Sixteen type 2 diabetic patients with glycosylated hemoglobin (HbA1c) levels above 10% despite ongoing combination therapy with sulphonylurea and metformin were selected. Former treatment regimen was continued for the first day followed by substitution of sulphonylurea therapy with different insulin analogs (0.4 U/kg/day) plus metformin. Blood samples were obtained from all patients at 24 and 72 hours. Plasma levels of arachidonic acid (AA, C20:4n6), dihomo-gamma-linolenic acid (DGLA, C20:3n6), eicosapentaenoic acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3) were determined by an optimized multiple reaction monitoring (MRM) method using ultra fast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Prostaglandin E₂ (PGE2) was measured in serum samples by enzyme immunoassay.

Results

All measured PUFAs were significantly increased after treatment with insulin analogs plus metformin compared to before treatment levels. The mean AA/EPA ratio was significantly lower after treatment with insulin analogs plus metformin. A 22% decrease was observed in PGE2 levels after treatment with insulin analogs plus metformin compared to pretreatment levels (p > 0.05).

Conclusion

The significant decrease in AA/EPA ratio indicates that insulin analog initiation therapy has anti-inflammatory properties by favoring the increase of n3 fatty acid EPA.

Nitrotyrosine formation and apoptosis in rat models of ocular injury

This study was performed to examine inducible nitric oxide synthase (NOS-2) expression, nitrotyrosine formation and apoptosis in rats with elevated intraocular pressure (IOP) and/or ocular inflammation. Ocular inflammation was induced via injection of intra-vitreal lipopolysaccharide (LPS) while IOP was elevated by episcleral vessel cauterization. Animals were randomized to one of the following conditions: elevated IOP, LPS, elevated IOP+LPS, and control. Immunohistochemical staining and western blot analysis of retinal lysates revealed NOS-2 and nitrotyrosine immunoreactivity in all disease groups. NOS-2 expression and protein nitration was significantly greater in rats with elevated IOP+LPS compared to elevated IOP, LPS, and control groups. Nitrite levels in the retina affirmed significantly increased levels of nitric oxide generation in LPS-treated rats with elevated IOP (346+/-23.8 microM) vs LPS-treated, elevated IOP and control groups (195.6+/-12.6, 130+/-2.5 and 76.6+/-15.6 microM, respectively). Retinal TUNEL staining showed apoptosis in all diseased groups. Percent of apoptotic cells was significantly greater in the elevated IOP+LPS group compared to LPS-treated or elevated IOP groups. Presented data illustrates that both elevated IOP and ocular inflammation augment NOS-2 expression, retinal protein nitration and apoptosis in rats.

Transmission electron microscopy and autofluorescence findings in the cornea of diabetic rats treated with aminoguanidine

BACKGROUND

The accumulation of advanced glycation end products (AGEs) has been implicated in the pathogenesis of diabetic keratopathy. The present study was aimed to understand if aminoguanidine (AG), an AGE inhibitor, was protective against the development of corneal complications in a diabetic rat model.

METHODS

Wistar rats were divided into three experimental groups: control, diabetic, and AG-treated diabetic. Diabetes was induced in rats via a single intraperitoneal injection (60 mg/kg) of streptozocin (STZ) and AG was administered in drinking water at a dose of 1 g/L. All animals were sacrificed at the end of 10 weeks and corneas from diabetic and nondiabetic rats were analyzed via transmission electron microscopy (TEM). Corneal autofluorescence measurements were also performed in all experimental groups.

RESULTS

Electron microscopic evaluation revealed that aminoguanidine treatment in diabetic rats prevented the formation of intracellular spaces between neighbouring cells in the superficial corneal epithelium. Hyperglycemia-induced degeneration of intracellular organelles and formation of cytoplasmic vacuoles in the corneal stroma was also prevented with the treatment of AG. Corneal autofluorescence detected in the diabetic group (5.98 +/- 2.17 Fi/mg protein) was found to be significantly greater than the control (3.92 +/- 0.56 Fi/mg protein) and the AG-treated diabetic group (4.18 +/- 0.59 Fi/mg protein) (p < 0.05).

INTERPRETATION

The presented data provide evidence that AG is preventive against corneal alterations in experimental diabetes.

Plasma homocysteine levels in noninsulin-dependent diabetes mellitus with retinopathy and neovascular glaucoma

AIM

This study was designed to evaluate plasma homocysteine levels in noninsulin-dependent diabetes mellitus patients (NIDDM) with preproliferative retinopathy and neovascular glaucoma. The experimental goal was to determine the relationship between plasma homocysteine content and the development of microvascular lesions.

METHODS

Plasma homocysteine levels were assessed in three experimental groups consisting of healthy controls (n = 30), NIDDM patients with preproliferative retinopathy (n = 20) and NIDDM patients with neovascular glaucoma (n = 20). Homocysteine levels were determined via a fluorescence polarization immunoassay method by an Abbot IMX instrument.

RESULTS

Plasma homocysteine levels in NIDDM patients with preproliferative retinopathy and neovascular glaucoma (n = 40) were found to be significantly higher than those of controls (n = 30) (p < 0.01). When statistical analysis was performed separately among the three experimental groups, no significant difference in plasma homocysteine levels were found in patients with preproliferative retinopathy compared to controls. However, homocysteine levels in patients with neovascular glaucoma were found to be significantly higher than the control group (p < 0.001). No significant difference in plasma homocysteine levels could be detected between patients with preproliferative retinopathy and neovascular glaucoma.

CONCLUSIONS

Hyperhomocysteinemia is a risk factor for the development of microvascular lesions in patients with NIDDM but cannot be used as a marker to assess the progression of lesions observed in neovascular glaucoma.

Effect of hypercholesterolemia on inducible nitric oxide synthase expression in a rat model of elevated intraocular pressure

PURPOSE

This study was performed to examine the effect of hypercholesterolemia on inducible nitric oxide synthase (NOS-2) expression and oxidative tissue injury in an experimental rat model of elevated IOP.

METHODS

Wistar rats were maintained on either regular chow or a high-cholesterol diet for 24 weeks. Intraocular pressure (IOP) was elevated in hypercholesterolemic rats by unilaterally cauterizing three episcleral vessels. Rats were divided into four experimental groups as follows; hypercholesterolemia, hypercholesterolemia+elevated IOP, elevated IOP and control. NOS-2 distribution, lipid peroxidation and retinal nerve fiber layer (RNFL) thickness was evaluated in all experimental groups at the end of 24 weeks.

RESULTS

Light microscopic evaluation of retinas in hypercholesterolemic rats revealed breaks and discontinuation in focal areas in the outer nuclear layer (ONL). NOS-2 positive staining was observed throughout the outer plexiform layer (OPL), inner plexiform layer (IPL) and ganglion cell layer (GCL) in rats with elevated IOP and/or hypercholesterolemia. Calculated values of RNFL thickness in hypercholesterolemic rats were significantly higher than those in the control and elevated IOP group. Vitreous malondialdehyde (MDA) levels detected in elevated IOP (3.51+/-0.31 nmol/mg protein) and hypercholesterolemia+elevated IOP (5.14+/-1.28 nmol/mg protein) groups were significantly higher than those detected in hypercholesterolemic (1.92+/-1.43 nmol/mg protein) and control (1.89+/-0.24 nmol/mg protein) groups.

CONCLUSION

The presented data confirms hypercholesterolemia as a risk factor in the development of glaucomatous optic neuropathy (GON) and suggests that increased circulating cholesterol may exacerbate disease progression by inducing NOS-2 expression and elevating oxidant tissue injury.

Prevalence of rheumatoid arthritis in Antalya, Turkey

The aim of this study was to evaluate the prevalence of rheumatoid arthritis (RA) in Antalya, Turkey. A cross-sectional study was performed face-to-face using a structured interview. Subjects were asked whether they had arthritis at present or previously. Subjects suspected of having RA were invited to the hospital for physical examination and laboratory investigations. Diagnosis of RA was confirmed if the patient fulfilled 1987 American College of Rheumatology (ACR) criteria for RA. A total of 3173 subjects were interviewed. The diagnosis of RA was established in 12 subjects. The prevalence of RA was determined as 0.38% [95% confidence interval (CI): 0.16-0.59]. The mean age was 49.92+/-11.56 years in subjects with RA and greater than that of other subjects (p<0.001). Of 12 subjects with RA, 9 had previously been diagnosed with the disease. Rheumatoid factor was detected in the sera of eight subjects. RA is less frequent in Turkey than in Northern Europe. Different genetic and environmental factors may have a role in this result.

Pentoxifylline contributes to the hepatic cytoprotective process in rats undergoing hepatic ischemia and reperfusion injury

AIM

Considerable efforts have been made to find and/or eliminate the underyling causes of hepatic ischemia-reperfusion injury, but many points are still unclear. Pentoxifylline-related cytoprotection is one of these unclear points. Our study tests the effects of pentoxifylline on the hepatic cytoprotective process in an experimental model.

MATERIALS AND METHODS

The animals were divided into two groups: (1) placebo-pretreated rats and (2) pentoxifylline-pretreated rats. After pretreatment, all rats underwent the hepatic ischemia-reperfusion procedure which was performed by clamping the hepatoduodenal ligament. To evaluate the liver injury, serum levels of alanine transaminase (ALT) and aspartate transaminase (AST), and liver tissue levels of prostaglandin E(2) (PGE(2)) were measured before ischemia, immediately after ischemia and immediately after reperfusion.

RESULTS

Before ischemia and immediately after ischemia, there were no significant differences between ALT and AST levels of groups 1 and 2 (p >0.05). However, at the end of reperfusion, ALT and AST levels of group 2 were significantly decreased when compared with group 1 (p < 0.05 and p < 0.01, respectively). Additionally, tissue levels of PGE(2) that were obtained before ischemia, immediately after ischemia and immediately after reperfusion in group 2 were significantly higher than those of group 1 (p < 0.001).

CONCLUSION

Pentoxifylline reduces reperfusion injury of the liver through significantly decreased transaminase levels, and contributes to hepatic cytoprotection by increasing tissue levels of PGE(2) significantly. These effects reflect the role of tissue PGE(2) in pentoxifylline-related hepatoprotection against ischemia-reperfusion injury of the liver.

Maternal serum screening for Down's syndrome, open neural tube defects and trisomy 18

Maternal serum screening identifies women at an increased risk of a pregnancy with Down's syndrome or trisomy 18 or an open neural tube defect. The triple test, consisting of maternal serum alpha-fetoprotein, unconjugated estriol and human chorionic gonadotropin was carried out by a chemiluminescence immunoassay method in our laboratory. The study consisted of 373 pregnant women. The gestational range for the study group was 14-22 weeks. The mean maternal age for the study group was 28.53 +/- 5.46 years (range 17.4 to 43.5 years); 9.1% of the women were considered at high risk for Down's syndrome based on the test results. In our study the detection rate for Down's syndrome by prenatal karyotyping was 66.6%. Maternal serum screening allows reduction of the number of women requiring amniocentesis without a significant decrease in the detection rate.

Effect of sulfur dioxide inhalation on erythrocyte antioxidant status and lipid peroxidation in experimental diabetes

The effect of sulfur dioxide (SO(2) ) on red cell antioxidant status and lipid peroxidation was examined in this research. Forty healthy male albino rats, aged three months, were divided into four equal groups: Control (C), SO(2) +C (CSO(2) ), diabetic (D) and SO(2) +D (DSO(2) ). Experimental diabetes mellitus was induced by i.v injection of alloxan with a dose of 50 mg/kg body weight. Ten ppm SO(2) was administered to the animals of SO(2) exposed groups in an exposure chamber for one hr/day x 7 days/wk x 6wks while other groups were exposed to filtered air in the same condition. SO(2) exposure, while markedly decreasing Cu, Zn-Superoxide dismutase (Cu, Zn-SOD) activity, significantly increased glutathione peroxidase (GSH-Px), catalase (CAT), glutathione (GSH) and glutathione-s-transferase (GST) activities and TBARS values in CSO(2) and DSO(2) groups compared with their respective control groups. From these results, it could be concluded that adaptative changes occurred in antioxidant systems that may counteract the free radical effect of SO(2) in the experimental groups.

A chemiluminescence assay detecting the antioxidative effects of glutathione and uric acid on erythrocytes and hemolysates exposed to t-butyl hydroperoxide

The aim of this study was to compare the antioxidative effects of glutathione (GSH) and uric acid (UA) on erythrocytes and hemolysates exposed to t-butyl hydroperoxide, by using a chemiluminescence (CL) technique. CL formation was induced by t-butyl hydroperoxide in an experimental system consisting of erythrocytes and hemolysates in Tris-HCl buffer (pH 7.4). GSH or UA was added as an antioxidant. In erythrocytes, 10 microM and 50 microM concentrations of either GSH or UA reduced the maximum chemiluminescence values (MCVs) significantly when compared to those of controls. In erythrocytes, MCVs observed in the 50 microM GSH group were significantly lower than those of the 50 microM UA group. In hemolysates, while 10 microM concentration of GSH or UA did not alter MCVs, 50 microM concentration of either GSH or UA reduced MCVs. The reduction of MCVs observed in the 50 microM GSH group was greater than that of the 50 microM UA group. When the effects of equimolar concentrations of GSH or UA on erythrocytes and hemolysates were compared, the MCVs of hemolysates were lower than those of erythrocytes. These results can be attributed to the fact that antioxidant agents react much more easily in the hemolysate medium.

Prevalence of erythrocyte pyruvate kinase deficiency and normal values of enzyme in a Turkish population

A pyruvate kinase deficiency prevalence study and determination of the normal levels of the enzyme were performed in Antalya city, Turkey. Heparinized blood samples obtained from a representative population of the Antalya province (617 women and 573 men) were tested for pyruvate kinase deficiency by qualitative and quantitative tests between April 1992 and March 1994. The mean pyruvate kinase activity was found to be 19.8 +/- 4.0 IU/g Hb whereas the enzyme activity of deficient cases varied between 7.5 and 12.2 IU/g Hb. Taking into account that pyruvate kinase deficiency is the second most common cause of nonspherocytic congenital hemolytic anemia, detection of deficient cases by genetic screening tests appears to be an informative clinical indicator of hemolytic anemia.

Increased resistance to oxidative stress in normal and glucose-6-phosphate dehydrogenase-deficient hemolysates in the presence of enzyme substrates

Erythrocytes and hemolysates from 10 normal and 10 glucose-6-phosphate dehydrogenase-deficient individuals were incubated with cumene hydroperoxide, and free radical-induced lipid peroxidation was monitored by chemiluminescence. Chemiluminescence intensities in erythrocytes of normal and deficient subjects were similar in the presence or absence of glucose-6-phosphate dehydrogenase substrates. Hemolysates of normal and deficient subjects also showed similar chemiluminescence in the absence of substrates. However, with the addition of substrates to the incubation medium, deficient hemolysates reached maximum chemiluminescence intensity within a shorter period, and maximum values were higher than in normal hemolysates. We believe this offers a new means of detection of glucose-6-phosphate dehydrogenase-deficient patients.

The effects of detergents on t-butyl hydroperoxide-induced chemiluminescence

We examined the effects of Triton X-100, digitonin, sodium dodecyl sulfate, taurocholic acid, and cetylpyridinium chloride on hemoglobin-catalyzed and t-butyl hydroperoxide-induced chemiluminescence. The experimental system contained hemoglobin, luminol, t-butyl hydroperoxide, and different concentrations of detergents (5-100 mg/dl) in TRIS-HCl buffer. Control assays were performed by excluding detergents. Chemiluminescence was detected using a liquid scintillation counter in single photon mode. All concentrations chosen for each detergent reduced the maximum chemiluminescence value and retarded the time that maximum chemiluminescence occurred. The most prominent reduction in maximum chemiluminescence was observed with 50 and 100 mg/dl digitonin. The smallest reduction was observed with 5 mg/dl sodium dodecyl sulfate, without retardation of the time that maximum chemiluminescence occurred. Our aim was to use detergents in membrane-containing experimental systems and hence to identify the detergent with the least effect on chemiluminescence. Our results suggest that sodium dodecyl sulfate is the most suitable detergent for chemiluminescence studies in membrane systems.

The role of antioxidants in the prevention of t-butyl hydroperoxide-induced chemiluminescence

An experimental system which assesses the antioxidant potential of ascorbic acid, glutathione, uric acid, and taurine was developed. The system comprised hemoglobin, luminol, t-butyl hydroperoxide, and different concentrations of antioxidants in TRIS-HCl buffer (pH 7.4). Control assays were performed by excluding antioxidants. Chemiluminescence was detected using a liquid scintillation counter in single photon mode. All antioxidants, when applied in the appropriate concentrations, decreased the maximum chemiluminescence values. The minimum concentrations which decreased the chemiluminescence values were defined for each of the antioxidants.

Continuous monitoring of hydroperoxide-induced peroxidation in human erythrocytes by low-level chemiluminescence

We studied the effect of cumene hydroperoxide, t-butyl hydroperoxide, and hydrogen peroxide on intact healthy human erythrocytes (15 g hemoglobin/dl) using chemiluminescence to monitor peroxidation. We measured the chemiluminescence spectrum, the process of hemolysis, the pH shift, and absorbance spectrum during the incubation with chemicals producing oxidative stress. Maximum chemiluminescence was reached with cumene hydroperoxide at about 50 min, but with t-butyl hydroperoxide at 100 min. The effect of organic hydroperoxide was concentration dependent, whereas the effect of hydrogen peroxide was independent of concentration. Peroxides induced hemolysis after 30 min. The pH shift to alkaline was observed in the first 20-min period. Incubation with organic hydroperoxides induced a decrease in absorption at 580, 545, and 345 nm. Hydrogen peroxide induced a decrease in the same period of time but this returned to the normal range by 120 min. There was no change in absorption at 420 nm with any of the peroxidative agents. Our results suggest that low-level chemiluminescence is a useful model for studying hydroperoxide-induced peroxidation in human erythrocytes.

Effect of vitamin E in the treatment of bovine-albumin-induced uveitis in rabbits

In order to assess the role of vitamin E, an antioxidant, in the treatment of uveitis, a controlled experimental study was carried out on 20 New Zealand albino rabbits with bovine-albumin-induced uveitis. In all vitamin-E-treated animals, clinical and histopathological study of the retina and uvea revealed no significant changes in comparison with those in untreated rabbits.

Erythrocyte glucose-6-phosphate dehydrogenase (1.1.1.49) deficiency in Antalya province, Turkey: an epidemiologic and biochemical study

Glucose-6-phosphate dehydrogenase (1.1.1.49) activity was assessed in 1986-1988 in blood samples from 1,521 individuals from 375 families living an Antalya city and adjacent villages by Beutler's fluorescence spot test. The families were randomly selected by the State Statistical Institute. Complete deficiency occurred in 7.4% of males and 1.8% of females. Mean enzyme activity was 6.77 +/- 1.07 IU/g Hb in normals and ranged between 0 and 0.48 IU/g Hb in those considered deficient. Kinetic measurements made with partially purified enzyme showed that GdB+ and GdB- variants were present in normal and in deficient subjects, respectively.