Mehmet Kemal Erbil

Plasma Apelin and ADMA Levels in Patients with Essential Hypertension

Both apelin and asymetric dymethyl arginine (ADMA) regulate blood pressures. Low apelin and high ADMA levels have been reported in several cardiometabolic disorders. However, there is no data about ADMA and apelin levels in essential hypertension and any relationship between them. We investigated a group of newly diagnosed and untreated 30 young hypertensive men and 30 healthy controls. Apelin levels were significantly lower and the ADMA levels were significantly higher in the patients (p = 0.04 for both). Both ADMA and apelin were related to the systolic blood pressures (SBP) (beta = −0.393, p = 0.003; beta = 0.285, p = 0.03, respectively). Future studies are necessary in order to clearly define the role of ADMA and apelin in the pathogenesis of essential hypertension.

The effects of thyroxine replacement on the levels of serum asymmetric dimethylarginine (ADMA) and other biochemical cardiovascular risk markers in patients with subclinical hypothyroidism

Background  The relationship between subclinical hypothyroidism (SH) and cardiovascular disease (CVD) is still under debate. The purpose of the present study was to evaluate plasma total homocysteine (tHcy), high sensitive C‐reactive protein (hsCRP), small dense low‐density lipoprotein (sdLDL), l‐arginine and asymmetric dimethylarginine (ADMA) concentrations and their relationship to nitric oxide (NO) production, measured as plasma nitrite‐plus‐nitrate (NOx) concentration, in patients with SH before and after thyroxine replacement therapy and compared with control group values.

Decreased small dense LDL levels in Gilbert's syndrome.

OBJECTIVE To investigate the role of small dense low density lipoprotein cholesterol (sd-LDL-C) in the mechanism of decreased incidence of cardiovascular disease in Gilberts syndrome (GS). DESIGN AND METHODS sd-LDL-C, ox-LDL, and high sensitive C reactive protein (hs-CRP) levels were investigated in subjects with GS (n=42) and compared to healthy controls (n=52). RESULTS Age, gender and body mass index (BMI) distributions were similar between the two groups. sd-LDL-C, ox-LDL and hs-CRP levels were lower in GS than the healthy controls (p<0.001, p<0.001 and p=0.001, respectively). Unconjugated bilirubin was negatively correlated with sd-LDL-C, ox-LDL and hs-CRP (r=-0.594, p<0.001; r=-0.249, p=0.016 and r=-0.373, p<0.001 respectively). In addition, sd-LDL-C was positively correlated with ox-LDL (r=0.307, p=0.003). CONCLUSIONS The findings of this preliminary study suggest that reduced sd-LDL-C, ox-LDL and hs-CRP levels may have a role in preventing atherosclerosis in subjects with GS.

Soluble CD40 ligand and soluble P-selectin levels in Gilbert's syndrome: A link to protection against atherosclerosis?

OBJECTIVE To investigate the role of CD40 ligand and P-selectin in the mechanism of decreased incidence of cardiovascular disease in Gilberts syndrome (GS). DESIGN AND METHODS The soluble forms of CD40 ligand (sCD40L) and P-selectin (sP-selectin), and high sensitive C reactive protein (hs-CRP) levels were investigated in subjects with GS (n=25) and compared to healthy controls (n=53). RESULTS sCD40L and hs-CRP levels were significantly lower in GS compared to the controls (0.33+/-0.27 vs 0.71+/-0.37 ng/mL, p<0.001 and 0.51+/-0.45 vs 1.16+/-1.31 mg/L, p=0.046, respectively). Both sCD40L and hs-CRP were negatively correlated with total bilirubin (r=-0.5, p<0.001 and r=-0.34, p=0.002, respectively). sP-selectin levels were lower in GS when compared to the controls but the difference did not reach statistical significance (p=0.052). No correlation was found between the plasma levels of sCD40L, sP-selectin and hs-CRP. CONCLUSION These novel findings suggest that reduced sCD40L and hs-CRP concentrations may have a role in the mechanism of protection against atherosclerosis in GS.

Plasma Melatonin and Urinary 6-Hydroxymelatonin Levels in Patients with Pulmonary Tuberculosis

Tuberculosis (TB) is the second most frequent cause of death in the world, after AIDS. Delay in diagnosing TB is an important worldwide problem. It seriously threatens public health. Cell-mediated immune responses play an important role in the pathogenesis of TB infection. The course of Mycobacterium tuberculosis (MTb) infection is regulated by two distinct T cell cytokine patterns. Melatonin is a biomolecule (mainly secreted by the pineal gland) with free radical scavenging, antioxidant and immunoregulatory properties. Melatonin has both its direct and indirect immunomodulatory effects on the immune system. In this study, we measured plasma melatonin and urine 6-hydroxy melatonin sulphate (6-HMS) concentrations in patients with newly diagnosed TB for the purpose of investigating whether there was a relationship between their levels and MTb infection. Thirty-one newly diagnosed patients presenting with active TB and 31 healthy subjects as the control group were included in this study. Blood and 24-h urine samples were collected from all individuals. Plasma melatonin levels and urine 6-HMS were measured. Our results show that in patients with TB, mean melatonin and 6-HMS concentrations were significantly lower than in the control subjects (p = 0.037, p < 0.001, respectively). We believe that the treatment of TB patients with melatonin might result in a wide range of health benefits including improved quality of life and reduced severity of infection in these patients. Supplementation with melatonin may be considered as an adjunctive therapy to classic treatment of pulmonary TB, especially during the acute phase of infection.

Elevated serum neopterin levels in acetaminophen-induced liver injury.

Neopterin is synthesized in macrophage/Kupffer cells by interferon-gamma and other cytokines. This study aimed to evaluate the utility of using neopterin as a biomarker of acetaminophen (APAP)-induced liver injury. Wistar rats, randomly divided into two groups (APAP and normal), received APAP (1.0 g/kg) and distilled water, respectively, by gastric tube. The APAP group had a higher degree of liver necrosis than the control group. The APAP group also had significantly higher serum neopterin levels than the normal group. Serum neopterin levels correlated with serum AST, ALT activities, and degree of necrosis. This study demonstrates the preclinical utility of neopterin as a biomarker for the animal model of APAP-induced liver injury. Further research studies are required to determine the preclinical opportunities of using neopterin as a marker of APAP-induced liver injury.

Circulating vaspin and its relationship with insulin sensitivity, adiponectin, and liver histology in subjects with non-alcoholic steatohepatitis.

Abstract Objective. Non-alcoholic steatohepatitis (NASH) is closely associated with components of metabolic syndrome. Vaspin is a novel adipocytokine that may link obesity, insulin resistance (IR), and type 2 diabetes mellitus. We aimed to investigate circulating vaspin levels in subjects with NASH and also to search for the association of vaspin with IR, adiponectin, and histological findings. Material and methods. A total of 50 male patients with NASH and 30 healthy male controls were enrolled. Vaspin and adiponectin were measured with ELISA method. Insulin sensitivity determined by homeostasis model assessment (HOMA-IR) index. Results. Plasma vaspin levels were higher and adiponectin levels were lower in NASH group compared with controls (p < 0.01 and p < 0.001, respectively). However, in multivariate analysis adjusted for glucose and lipid parameters, and HOMA-IR indexes, the difference in vaspin concentrations was disappeared. Nonetheless, the difference regarding the adiponectin levels remained significant between groups (p = 0.03). Vaspin was negatively correlated with low-density lipoprotein cholesterol (r = -0.32, p = 0.03) in subjects with NASH. Conclusions. This study indicates that circulating vaspin levels are not altered in male subjects with NASH. These results suggest that in the absence of metabolic risk factors, vaspin per se may not be involved in the pathogenesis of NASH.

Plasma total homocysteine concentrations in a Turkish population sample.

Objectives — The purpose of this study is to determine the reference of plasma total homocysteine levels from a Turkish population and to investigate the relationship of plasma total homocysteine levels with sex and age groups. Design and methods — Plasma total homocysteine levels were measured in 2257 Turkish individuals (1381 men and 876 women) aged 1-90 years. Plasma total homocysteine concentrations were determined using high performance liquid chromatography with fluorescence detector. Results — The mean plasma total homocysteine level was significantly higher in men (mean, 10.6 μmol/L) than in women (mean, 8.7 μmol/L), P < 0.001. The mean plasma total homocysteine levels for the 1-10, 11-20, 21-30, and 31-40, 41-50, 51-60, and 61-70, 71-80, 81-90 age groups, were 6.5, 9.6, 10.1, and 10.4, 10.5, 10.9, and 11.3, 12.7, 14.6 μmol/L in men and 7.1, 7.6, 7.5, and 7.8, 8.7, 9.4, and 10.3, 11.2, 13.3 μmol/L in women, respectively. Conclusions — These data indicate the significance of sex- and age-associated differences of plasma total homocysteine levels in Turkish subjects. Plasma total homocysteine levels were increasing with age and men were found to have higher levels than women, as is found in other populations.

Pressure-related Increase of Asymmetric Dimethylarginine Caused by Hyperbaric Oxygen in the Rat Brain: A Possible Neuroprotective Mechanism

A decrease in nitric oxide availability in the brain tissue due to the inhibition of nitric oxide synthase (NOS) activity during the early phases of hyperbaric oxygen (HBO) exposure was found to be involved in hyperoxic vasoconstriction leading to reduced regional cerebral blood flow. We hypothesized that the concentration of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), may be an important factor during this hyperoxic vasoconstriction state. Rats were exposed to 1, 2 and 3 atmospheres pure oxygen for two hours. A fourth group of animals served as control. Asymmetric dimethylarginine, L-Arginine and nitrite/nitrate (NOx) concentrations were measured from deproteinized rat brain cytosols. In rat brains exposed to 3 atmospheres O2, ADMA and L-Arginine levels were found to be significantly higher and NOx significantly lower than control levels. Additionally, statistically significant correlations between ADMA and L-Arginine, and ADMA and NOx concentrations were detected. In conclusion, this is the first study indicating increased ADMA levels in rat brains exposed to HBO. The simultaneously decreased NOx values suggest that ADMA elevation resulted in NOS inhibition and therefore may be responsible for the early phase hyperoxic vasoconstriction.

Comparison of two Methods for Malondialdehyde Measurement

Aim In this study, we aimed to measure malondialdehyde levels by two different methods and compare these methods.