Asymmetric Dimethylarginine and Its Relation As a Biomarker in Nephrologic Diseases

Impact of Physical Activity and Natural Bioactive Compounds on Endothelial Dysfunction in Chronic Kidney Disease

Chronic kidney disease (CKD) represents a world-wide public health problem. Inflammation, endothelial dysfunction (ED) and vascular calcifications are clinical features of CKD patients that increase cardiovascular (CV) mortality. CKD-related CV disease pathogenic mechanisms are not only associated with traditional factors such as arterial hypertension and dyslipidemia, but also with ED, oxidative stress and low-grade inflammation. The typical comorbidities of CKD contribute to reduce the performance and the levels of the physical activity in nephropathic patients compared to healthy subjects. Currently, the effective role of physical activity on ED is still debated, but the available few literature data suggest its positive contribution. Another possible adjuvant treatment of ED in CKD patients is represented by natural bioactive compounds (NBCs). Among these, minor polar compounds of extra virgin olive oil (hydroxytyrosol, tyrosol and oleocanthal), polyphenols, and vitamin D seem to exert a beneficial role on ED in CKD patients. The objective of the review is to evaluate the effectiveness of physical exercise protocols and/or NBCs on ED in CKD patients.

The Importance of a New Cardiovascular Risk Factor - Asymmetric Dimethylarginine

In the past years, scientific research has highlighted the presence of a new cardiovascular risk factor, the implications of which have not been sufficiently studied so far. It is different from conventional risk factors because it acts independently at the endothelial level, having important proatherogenic properties. Through its action, this risk factor leads to increased oxidative stress and promotes the onset of atherosclerosis faster than other well-known risk factors so far. Asymmetric dimethylarginine (ADMA) is a methylprotein that arises from posttranslational methylation of proteins. Its importance has emerged in recent years, when the rate of cardiovascular mortality among patients with chronic kidney disease has been high. The distinctive element of this risk factor compared to other well-known ones is given by its ability to compete directly with nitric oxide synthase, being its strongest endogenous inhibitor, with strong proatherogenic attributions. Given that ADMA has tight correlations with atherogenesis and endothelial damage, its assessment should be taken into consideration for any patient who has been recently diagnosed with high blood pressure.

Ratiometric assay of CARM1 activity using a FRET-based fluorescent probe

One of the regulatory mechanisms of epigenetic gene expression is the post-translational methylation of arginine residues, which is catalyzed by protein arginine methyltransferases (PRMTs). Abnormal expression of PRMT4/CARM1, one of the PRMTs, is associated with various diseases, including cancers. Here, we designed and synthesized a Förster resonance energy transfer (FRET)-based probe, FRC, which contains coumarin and fluorescein fluorophores at the N-terminus and C-terminus of a peptide containing an arginine residue within an appropriate amino acid sequence to serve as a substrate of CARM1; the two fluorophores act as a FRET donor and a FRET acceptor, respectively. Since trypsin specifically hydrolyzes the arginine residue, but not a monomethylarginine or dimethylarginine residue, CARM1 activity can be evaluated from the change of the coumarin/fluorescein fluorescence ratio of FRC in the presence of trypsin.

Atherogenic Index of Plasma: Novel Predictive Biomarker for Cardiovascular Illnesses

BACKGROUND/AIM

Cardiovascular diseases (CVD) are the most important cause of mortality globally. Nevertheless, the World Health Organization have declared that a precise and quick recognition of susceptible individuals to develop CVD is imperative to combat those illnesses. Additionally, developing countries need affordable alternatives to effectively prognosticate cardiovascular events. Therefore, the objective of this study was to assess well-established clinical prognostic markers in Mexican women to identify affordable, specific, and useful tools to predict cardiovascular events.

MATERIAL AND METHODS

A cross-sectional study was performed including 340 healthy women. Anthropometric and clinical measurements were acquired from all enrolled individuals. Also, a blood sample of each participant women was obtained to complete biochemical analyses (triglycerides, glucose, total cholesterol, LDL cholesterol, and HDL cholesterol), and serum asymmetric dimethylarginine (ADMA), and adipocyte-fatty acid binding protein (FABP4) determinations. Finally, with anthropometric, clinical and biochemical determinations, atherogenic indices (Framingham risk score, Castelli's risk index, and atherogenic index of plasma) were estimated.

RESULTS

A mean value of 6.5 ± 7.2 was detected for the Framingham risk score, 3.7 ± 1.3 for Castelli's risk index, and 0.12 ± 0.22 for the atherogenic index of plasma (AIP). Circulating mean ADMA and FABP4 levels found in assessed women were 0.68 ± 0.34 mmol/L and 20.3 ± 16.6 ng/mL, respectively. Furthermore, strong positive relationships (p <0.05) between AIP and serum FABP4 and ADMA concentrations were detected after adjustment by traditional CVD risk factors.

CONCLUSION

In conclusion, AIP could be recommended as a potential biomarker in the early diagnosis of CVD events in developing countries.

Asymmetrical Dimethylarginine Levels in Hepatitis B Virus-Positive Patients

BACKGROUND

High asymmetrical dimethylarginine (ADMA) levels have been associated with endothelial dysfunction and contribute to the development of several diseases. However, data on the relationship between hepatitis B virus (HBV) and ADMA are limited. The aim of our study was to explore the relationship between ADMA and HBV by comparing the ADMA levels in patients with chronic active hepatitis B (CHB), inactive HBV carriers (carriers), and healthy volunteers (controls).

METHODS

The participants were divided into three groups: 90 patients with CHB, 90 HBV carriers, and 90 controls. Serum ADMA levels were quantified using an ELISA kit (Cusabio, Wuhan, China). The data were analyzed using an ANOVA or the Kruskal-Wallis test as appropriate, with P<0.05 considered significant.

RESULTS

Serum ADMA levels were significantly higher in patients with CHB (228.35±91.10 ng/mL) than in HBV carriers (207.80±75.80 ng/mL) and controls (207.61±89.10 ng/mL) (P=0.049). The clinical scores of the patients were positively correlated with ADMA levels.

CONCLUSIONS

The elevated serum ADMA levels in patients with CHB confirm that HBV plays a role in vasculitis. Further investigation of the mechanisms contributing to the high levels of ADMA in CHB may contribute toward development of new treatment modalities.

Forskolin attenuates doxorubicin-induced accumulation of asymmetric dimethylarginine and s-adenosylhomocysteine via methyltransferase activity in leukemic monocytes

Doxorubicin (DOX) is an antitumor drug, associated with cardiomyopathy. Strategies to address DOX-cardiomyopathy are scarce. Here, we identify the effect of forskolin (FSK) on DOX-induced-asymmetric-dimethylarginine (ADMA) accumulation in monocytoid cells. DOX-challenge led to i) augmented cytotoxicity, reactive-oxygen-species (ROS) production and methyltransferase-enzyme-activity identified as ADMA and s-adenosylhomocysteine (SAH) accumulation (SAH-A). However, except cytotoxicity, other DOX effects were decreased by metformin and FSK. FSK, did not alter the DOX-induced cytotoxic effect, but, decreased SAH-A by >50% and a combination of three drugs restored physiological methyltransferase-enzyme-activity. Together, protective effect of FSK against DOX-induced SAH-A is associated with mitigated methyltransferase-activity, a one-of-a-kind report.

Relation of Serum ADMA, Apelin-13 and LOX-1 Levels with Inflammatory and Echocardiographic Parameters in Hemodialysis Patients

Cardiovascular diseases are the leading causes of mortality in patients with chronic kidney disease. Nitric oxide has a critical role in both endothelial dysfunction and the atherosclerosis process. We aimed to investigate the relationships between serum asymmetric dimethyl arginine (ADMA), LOX-1, and Apelin-13 levels, which are known to act over nitric oxide with endothelial dysfunction and cardiac morphology as well as with each other in hemodialysis patients. The study comprised a total of 120 patients (53 females and 67 males) receiving hemodialysis three times a week for at least 6 months and an age-gender matched control group (55 females and 58 males). Serum ADMA, LOX-1, and Apelin-13 levels were measured using the ELISA technique. Echocardiography, 24-h blood pressure monitoring by the Holter and carotid artery intima-media thickness (CIMT) measurement was performed on all of the included subjects. The associations between serum ADMA, LOX-1, and Apelin-13 levels with CIMT, echocardiographic parameters [left ventricular mass (LVM) and left ventricular mass index (LVMI)], and inflammatory markers [high sensitive C-reactive protein (hsCRP) and neutrophil lymphocyte ratio (NLR)] were evaluated by correlation analysis. Serum ADMA, Apelin-13, and LOX-1 levels were significantly higher in the hemodialysis group than the controls (P < 0.001, P < 0.001, and P < 0.001, respectively). CIMT, hsCRP, and NLR levels were also significantly higher in the hemodialysis group (P < 0.05, P < 0.001, P < 0.001, respectively). Significant correlations were observed among the serum ADMA, Apelin-13, and LOX-1 levels. Moreover, notably positive correlations were found between these three biochemical markers and LVM, LVMI, hsCRP, and CIMT. Serum ADMA, Apelin-13, and LOX-1 levels can be indicators not only for the inflammatory process but also for the pathogenesis of cardiovascular diseases in hemodialysis patients.