Correlation between salivary and serum oxidized LDL levels: a pilot study on overweight/obese subjects

BACKGROUND

Saliva contains a variety of substances and could be functionally equivalent to serum in reflecting the physiological state of the body, including metabolic variations. Salivary samples are non-invasive, safe, and easier to handle than serum. Oxidized LDL cholesterol (oxLDL) is an additional cardiovascular risk factor playing an important role in atheromatous plaque formation; overweight/obese subjects present an increase in oxLDL concentrations. The aims of the study were to assess oxLDL salivary levels, if detectable, and to verify their possible correlation with serum in overweight/obese subjects.

METHODS

Thirty-five consecutive overweight/obese subjects and 10 normal weight controls were enrolled. Serum and salivary oxLDL levels were measured by a commercial enzyme-linked-immunosorbent assay (ELISA method).

RESULTS

oxLDL levels were detectable in salivary samples and correlated (P = 0.001) with serum levels. Overweight/obese subjects showed serum and salivary oxLDL levels higher than controls (P = 0.000 and P = 0.022, respectively).

CONCLUSIONS

Our study showed the presence of oxLDL in salivary samples and highlighted a correlation between salivary oxLDL levels and their counterpart in serum. Moreover, salivary oxLDL levels were higher in overweight/obese subjects than in controls. Therefore, a salivary sample could be functionally equivalent to serum in monitoring cardiovascular risk in overweight/obese subjects.

Oxidative Stress and Low-Grade Inflammatory Status as Cardiometabolic Risk Factors in Italian Occupational Overweight/Obese Subjects

Obesity is associated with increased risk of cardiometabolic diseases. Adipocytokines (e.g. leptin), produced by the endocrine function of adipose tissue, can contribute to cardiometabolic risk in overweight and obese people. Oxidative stress, imbalance between oxidants and antioxidants, is considered a cardiovascular risk factor. High serum oxidized LDL (oxLDL) levels, marker of lipid peroxidation, a primary cause of atherosclerosis, can contribute to its progression. The aims of this study are to assess markers of oxidative status and cytokine profile and evaluate their role as cardiometabolic risk factors and possible correlations. In this cross-sectional study, we enrolled 76 occupational overweight-obese adults (46 females, 30 males; aged 46.8±9.5; BMI 33.7±4.8 kg/m2) without any previous cardiovascular disease. Oxidative status was measured by evaluating serum Reactive Oxygen Species (ROS) levels, Total Antioxidant Capacity (TAC) and oxLDL concentrations. All subjects' soluble cytokine and adhesion molecule levels were evaluated by cytofluorimetric method and compared with 35 controls matched for sex and age. ROS and oxLDL levels were high in 84% and 92% of the study population, respectively, despite adequate TAC (68%). Female ROS levels were significantly higher than those of males (414±99.3 vs 318±48.2 UCarr, p<0.0001), while their oxLDL levels were lower (95.3±22 vs 105.2±19.4 U/L, p=0.1). Leptin and sICAM-1 (intracellular adhesion molecule involved in leukocyte migration to inflamed area) levels of the study population were significantly higher than those of controls (93.8±89.1 vs 25.3±23 ng/mL, p=0.0002 and 505.8±236.7 vs 339.2±119.6 ng/mL, p=0.0009, respectively). Overweight/obese occupational subjects showed oxidative stress conditions accompanied by low chronic inflammatory status, possibly contributing to increased cardiometabolic risk.

Oxidative stress and homocysteine metabolism in patients with lupus nephritis

The objective of this study was to compare oxidative status and homocysteinemia in patients with lupus nephritis (LN) and in controls. Total antioxidant capacity (TAC), reactive oxygen species (ROS), homocysteine and related vitamins were measured in 68 patients with LN and in 50 controls. LN patients had lower TAC (p = 0.05) and higher ROS and homocysteinemia (p = 0.01) than controls. TAC, significantly lower in active than in quiescent LN (p = 0.01), was correlated with albuminemia (p = 0.02), inversely with proteinuria (p = 0.01) and anti-DNA antibodies (p = 0.004). ROS values, higher both in active and in inactive LN, correlated with age (p = 0.02), C-reactive protein (CRP) (p = 0.0005) and inversely with prednisone dosage (p = 0.05). At multivariate analysis, CRP (p = 0.04) and age (p = 0.005) were independent ROS predictors. Homocysteine, higher in active than in quiescent LN (p = 0.016) and in patients with antiphospholipid antibodies (p=0.05), correlated with serum creatinine (p = 0.00001) and proteinuria (p = 0.015). At multivariate analysis serum creatinine (p = 0.006) and active nephritis (p = 0.003) were independent predictors of hyperhomocysteinemia. Patients with LN showed impaired oxidative status, even without clinical signs of renal activity. ROS production may be counterbalanced by adequate antioxidant capacity in some patients with quiescent LN. The association of hyperhomocysteinemia and antiphospholipid antibodies positivity may increase the risk of cardiovascular and/or thrombotic events in LN patients.

Effects of combined dietary supplementation on oxidative and inflammatory status in dyslipidemic subjects

BACKGROUND AND AIM

Dyslipidemia is one of the main risk factors for atherosclerosis, usually the underlying cause of cardiovascular diseases which are the major cause of morbidity and mortality in developed countries. The aim of this study was to assess the effects and the advantages of a combined dietary supplementation with PUFA n-3, vitamin E, niacin and gamma-oryzanol on lipid profile, inflammatory status and oxidative balance.

METHODS AND RESULTS

Fifty-seven dyslipidemic volunteers were randomly assigned to receive: placebo (group A, 19 subjects); PUFA n-3 and vitamin E (group B, 18 subjects); the same as B plus gamma-oryzanol and niacin (group C, 20 subjects). Lipid profile, reactive oxygen species (ROS), total antioxidant capacity (TAC), vitamin E, interleukin 1-beta (IL1-beta), tumor necrosis factor (TNF-alpha) and thromboxane B2 (TXB2) were determined at baseline (T0) and after four months (T1). All dyslipidemic subjects showed, at baseline, oxidative stress and, after four months, all biochemical markers improved significantly in groups treated with dietary supplementation. Particularly in group C all lipid patterns improved significantly.

CONCLUSIONS

Our findings demonstrate that the strategy of combining different compounds, which protect each other and act together at different levels of the lipid chain production, improves lipid profile, inflammatory and oxidative status, allowing us to reduce the dose of each compound under the threshold of its side effects.

[Intravenous folinic acid and vitamin B12 supplementation and homocysteine concentration in hemodialysis patients]

INTRODUCTION

Hyperhomocysteinemia is one of the causes of the increased incidence of cardiovascular disease in uremia. Since homocysteine (Hcy) metabolism depends on the availability of folate and vitamin B12, we have measured the effects of chronic i.v. supplementation of folinic acid and vitamin B12 in a group of patients on maintenance hemodialysis.

METHODS

We compared the blood concentration of total Hcy (tHcy), vitamin B12 and folate and the intraerythrocyte concentration of folate in a group of 27 hemodialysis patients (Treated group), given an i.v supplementation with folinic acid (0.9 mg) and Vitamin B12 (cyanocobalamine 1.5 mg and hydroxycobalamine 1.5 mg) three times per week at the end of each dialysis session with those measured in a similar group of 28 hemodialysis patients without supplementation (No Treatment group). The patients were also characterized for the thermolabile variant (mutation C667-->T) of the enzyme methylene-tetrahydrofolate reductase (tMTHFR).

RESULTS

High plasma levels (< 11.7 micromol/L) of tHcy were observed in 54/55 patients. T patients had Hcy values significantly lower than NT ones (31.7+/-3.6 vs. 1.1+/-8.3micromol/L, p < 0.05). Serum vitamin B12 (1200 73.6 vs. 762+/-72.2 pmol/L, p < 0.001) and intraerythrocyte folate levels were also significantly higher in the T group (2176+/-127 vs. 1511+/-156, p < 0.005), while no significant difference was observed for serum folate. The distribution of tMTHFR genotypes was similar in the two groups. Homozygous patients showed higher levels of Hcy in comparison with wild type patients both in the whole population (62.32+/-15.9 vs.30.43+/-3.2, p < 0.05) and in the NT group (87.8+/-25.3 vs.36.8+/-13.1., p < 0.05), while no significant difference was observed among genotypes in the T group.

CONCLUSIONS

Uremic patients on hemodialysis, when supplemented with even low i.v. dose of folinic acid and vitamin B12, show significantly lower plasma levels of tHcy than non-supplemented patients.

Oxidative stress and homocysteine in coronary artery disease

BACKGROUND

Oxidative stress is present in cardiovascular diseases (CVDs), and hyperhomocysteinemia, an independent risk factor for these diseases, may play a role by inducing production of oxygen free radicals.

METHODS

To evaluate the possible role of homocysteine (Hcy) in inducing oxidative stress in coronary artery disease (CAD), plasma Hcy was measured in 68 consecutive cardiovascular patients, and plasma malondialdehyde (MDA), both free and total (free + bound), was measured in 40 patients with CAD (18 with chronic stable angina and 22 with unstable angina). As controls, we tested 70 healthy volunteers. Hcy was measured by an immunoenzymatic method and MDA, an index of lipid peroxidation, by gas chromatography-mass spectrometry.

RESULTS

Plasma Hcy concentrations were significantly higher in cardiovascular patients than in controls (10.2 vs 8.9 micromol/L; P <0.0002), with no significant difference between values in the stable and unstable angina subgroups. Similarly, total MDA was significantly higher in the CAD group than in the controls (2.6 vs 1.3 micromol/L; P <0.00001), again with no significant difference between stable and unstable angina patients. By contrast, free MDA, which was significantly higher in the CAD patients than the controls (0.4 vs 0.2 micromol/L; P < 0.00001), was also significantly higher in the unstable than in the stable angina group (0.5 vs 0.3 micromol/L; P <0.03). However, no correlation was observed among Hcy and free and total MDA.

CONCLUSIONS

Our findings show that a moderate increase of Hcy is associated with CVD but that Hcy at the detected values cannot be considered completely responsible for oxidative damage. That lipid peroxidation is involved in CAD is shown by our observation of significantly increased plasma free and total MDA concentrations compared with controls. Moreover, free MDA values discriminated between unstable and chronic stable angina, and could thus represent a new diagnostic tool.

Central nervous system trans-synaptic effects of acute axonal injury: a 1H magnetic resonance spectroscopy study

N-acetylaspartate (NAA) has previously been proposed as a neuronal marker. 1H magnetic resonance spectroscopy (MRS) is able to detect NAA in brain, and decreases of NAA have been documented after brain injury. The reason for this decrease is not fully understood and neuron loss damage and "dysfunction" have all been proposed. It is hypothesized that acute central nervous system (CNS) deafferentation causes a trans-synaptic NAA decrease and that high resolution 1H MRS is able to detect such a decrease. To test this hypothesis, an experimental model was used in which axonal lesions were obtained by stretch injury in guinea pig right optic nerve (95-99% crossed fibers). The trans-synaptic concentration of NAA, total creatine (Cr), and the NAA/Cr ratio in lateral geniculate bodies (LGB) and superior colliculi (SC) sample extracts were measured 72 h later by high resolution 1H MRS. In the left LGB/SC, which is where right optic nerve fibers project, reductions of NAA and NAA/Cr were found whereas Cr levels were normal. NAA, NAA/Cr, and Cr values were all normal in the right LGB/SC. Histology and EM findings revealed no abnormalities. At 7 days, left LGB/SC NAA and NAA/Cr values were in the normal range. It was concluded that 1) acute deafferentation in the CNS causes a trans-synaptic decrease of NAA levels that can be detected by 1H MRS and 2) NAA decrease may be due to changes of NAA metabolism caused by functional neuronal inactivity rather than neuronal loss, injury or "dysfunction." 1H MRS is a potential tool for the study of functional effect of CNS lesions in vivo.

Hepatic cholesterol synthesis in man: effect of diazepam and other drugs

The hepatic synthesis of cholesterol-measured as incorporation of 14C-acetate into digitonin-precipitable sterols-has been evaluated in needle biopsy material of normal untreated patients and patients under short-term treatment with Diazepam, Phenobarbital, Chlorpromazine or Diphenylhydantoin. A significant increase of cholesterol synthesis was observed in the first two groups with much higher levels of incorporation in the Diazepam-treated patients. Moreover in this group the levels were still elevated from 4 to 7 days after drug withdrawl. Ultrastructural and morphometric studies performed on the same biopsy material showed a significant increase of smooth endoplasmic reticulum in hepatocytes of Diazepam-treated patients; in addition, there seemed to be a positive correlation between the increased cholesterol synthesis and the formation of areas of non vesicular, type 2, smooth endoplasmic reticulum. These findings suggest an early stimulation of the liver cell microsomal system by Diazepam in man; they also point to side effects of some drugs, which are not predictable from studies in Wistar rats.