The Relationship of Methylated Arginines with Urine Cadmium Levels

BACKGROUND

In this study, we aimed to show that methylated arginines are the predictors of non-clinical atherosclerotic cardiovascular complications in metal workers exposed to Cd.

METHODS

The 80 Cd-exposed metal workers and 80 non-exposed workers (control) included in the study were available for measuring arginine, ADMA, SDMA, and L-NMMA levels.

RESULTS

The average urine Cd levels (CdU) found were 1.03 ± 0.8 µg/g creatinine (0.84 ± 0.65 µg/L) ranging from 0.01 to 3.00 µg/g creatinine in the control group and 5.41 ± 5.2 µg/g creatinine (4.29 ± 3.81 µg/L) ranged from 0.11 to 27.2 µg/g creatinine in metal workers. On the other hand, the median ratios of the different groups (exposed and control) were found to be 449.35 and 483.88 for arginine/ADMA and 1.28 and 1.33 SDMA/ADMA, respectively.

CONCLUSIONS

The present study was undertaken to investigate the relationship between cadmium exposure and methylated arginines such as ADMA/SDMA/L-NMMA parameters which is important for the early detection atherosclerotic cardiovascular diseases.

Assessment of potential cardiovascular risk in trichloroethylene exposure by serum methylated arginine levels

Trichloroethylene (TCE) is a widely used solvent in industrial applications and has toxic effects on various systems. Methylated arginine amino acids (eg asymmetric dimethyl arginine (ADMA), symmetric dimethyl arginine (SDMA)) cause the development of cardiovascular disease by inhibiting NO synthesis, which is considered to be heart-protector. The aim of this study is to determine the risk of cardiovascular diseases in TCE exposure by methylated arginine biomarkers. About 98 controls and 100 TCE-exposed male subjects were included in the study. Trichloroacetic acid (urinary metabolite of TCE), arginine, homoarginine, citrulline ADMA, SDMA, and N-monomethyl L-arginine (L-NMMA) levels were found significantly higher than control group (p < 0.001). The strongest correlation was found between ADMA and Trichloroacetic acid (TCA) level (r = 0.453, p < 0.01). Long-term TCE exposure, may be an important risk factor for cardiovascular diseases by increasing methylated arginine levels.

The relationship between impaired lung functions and cytokine levels in formaldehyde exposure

Exposure to formaldehyde (FA) causes detrimental effects on respiratory system. Inflammation is one of the mechanisms responsible for these effects. Our aim is to demonstrate the possible effect of formaldehyde on inflammation biomarkers and pulmonary function tests. One hundred ninety-eight male workers in a fiber production factory are included. Eighty two of them were not exposed to FA. Thirty nine workers were exposed to FA for 4 h or more in a work shift and 77 workers were exposed less than 4 h. Statistically significant differences were found for FA, TNF-α, and IL-6 levels and pulmonary function test parameters (FEV1 and FVC) between no exposure and exposure groups. The results revealed a correlation between decrement in pulmonary function tests and an increase in cytokine levels concordant with the duration of FA exposure. The results may emphasize that FA exposure shows its effect on pulmonary system via inflammatory pathways.

Assessment of Endothelial Dysfunction with Methylated Arginines and L-arginine in Cadmium-Exposed People: a Pilot Study

BACKGROUND

Workers can be exposed to cadmium (Cd) in various industries. On the other hand, another potential source for Cd exposure is the food chain and smoking. Environmental pollution to Cd plays an important role in the development of atherosclerosis. Asymmetric dimethyl arginine (ADMA) levels promote the development of endothelial dysfunction and atherosclerosis-related diseases such as hypertension, acute coronary syndrome, congestive heart failure, and peripheral vascular diseases. The aim of this study is to evaluate the cardiovascular risks of non-symptomatic cadmium-exposed workers and to promote the value of methylated arginines in screening of toxic exposures.

METHODS

A total 176 participants were included in the study which has been separated as control group (n = 79) and Cd-exposed group (n = 94). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for toxicological analysis of Cd levels. Also, liquid Chromatography-Mass Spectrometry (LC-MS/MS) was used for levels of methylated arginines such as ADMA, symmetric dimethylarginine (SDMA), NG-monomethyl-L-arginine (L-NM-MA), homoarginine, and citrulline.

RESULTS

Statistically significant differences were observed for control and Cd-exposed groups, respectively as follows: Cd levels (0.25 ± 0.13 µg/L and 1.33 ± 0.61 µg/L), ADMA (0.16 ± 0.04 µmol/L and 0.22 ± 0.11 µmol/L), SDMA (0.21 ± 0.06 µmol/L and 0.27 ± 0.07 µmol/L), L-NMMA(0.02 ± 0.01 µmol/L and 0.03 ± 0.01μmol/L), and arginine/ADMA levels (695.82 ± 620.63 and 478.30 ± 432.61).

CONCLUSIONS

Our results suggest that workers chronically exposed to Cd showed imbalances in endothelial parameters.

Chronic variable physical stress during the peripubertal-juvenile period causes differential depressive and anxiogenic effects in the novelty-seeking phenotype: functional implications for hippocampal and amygdalar brain-derived neurotrophic factor and the mossy fibre plasticity

Experimentally naive rats show variance in their locomotor reactivity to novelty, some displaying higher (HR) while others displaying lower (LR) reactivity, associated with vulnerability to stress. We employed a chronic variable physical stress regimen incorporating intermittent and random exposures of physical stressors or control handling during the peripubertal-juvenile period to assess interactions between stress and the LRHR phenotype in depressive- and anxiety-like behaviors on the forced swim and social interaction tests, respectively. A decrease in immobility in the forced swim test along with a decrease in social contact in the social interaction test were observed in the juvenile HRs, coupled with increases in brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus and in the basolateral amygdala with chronic variable physical stress. In contrast, an increase in immobility in the forced swim test and a decrease in social contact was observed in the LR counterparts coupled with an increase in the BDNF mRNA in the basolateral amygdala following chronic variable physical stress. Furthermore, chronic physical stress led to increased H3 and H4 acetylation at the P2 and P4 promoters of the hippocampal BDNF gene in the HR rats that is associated with increased suprapyramidal mossy fibre (SP-MF) terminal field volume. In contrast, chronic variable physical stress led to decreased H4 acetylation at the P4 promoter, associated with decreased SP-MF volume in the LR rats. These findings show dissociation in depressive- and anxiety-like behaviors following chronic variable physical stress in the juvenile HR animals that may be mediated by increased levels of BDNF in the hippocampus and in the amygdala, respectively. Moreover, chronic variable physical stress during the peripubertal-juvenile period results in opposite effects in depressive-like behavior in the LRHR rats by way of inducing differential epigenetic regulation of the hippocampal BDNF gene that, in turn, may mediate mossy fibre sprouting.

Biomechanical effects of rapid maxillary expansion on the craniofacial skeleton, studied by the finite element method

The aim of this study was to evaluate the biomechanical effect of rapid maxillary expansion (RME) on the craniofacial complex by using a three-dimensional finite element model (FEM) of the craniofacial skeleton. The construction of the three-dimensional FEM was based on computer tomography (CT) scans of the skull of a 12-year-old male subject. The CT pictures were digitized and converted to the finite element model by means of a procedure developed for the present study. The final mesh consisted of 2270 thick shell elements with 2120 nodes. The mechanical response in terms of displacement and von Mises stresses was determined by expanding the maxilla up to 5 mm on both sides. Viewed occlusally, the two halves of the maxilla were separated almost in a parallel manner during 1-, 3- and 5-mm expansions. The greatest widening was observed in the dento-alveolar areas, and gradually decreased through the superior structures. The width of the nasal cavity at the floor of the nose increased markedly. However, the postero-superior part of the nasal cavity was moved slightly medially. No displacement was observed in the parietal, frontal and occipital bones. High stress levels were observed in the canine and molar regions of the maxilla, lateral wall of the inferior nasal cavity, zygomatic and nasal bones, with the highest stress concentration at the pterygoid plates of the sphenoid bone in the region close to the cranial base.