Serum total and lipid-bound sialic acid levels following acute myocardial infarction

Variations in the Serum Sialic Acid Profiles of Malaria Patients in Zaria, Nigeria: A Cross-Sectional Study

PURPOSE

Understanding some variations in specialized molecules during malaria could facilitate adequate monitoring of patients and reduce the fatalities caused by the disease. The present study reports changes in the levels of free serum sialic acid (FSSA) among Plasmodium-infected individuals in Zaria, Nigeria, in a cross-sectional study with 170 individuals.

METHODS

The FSSA and total sialic acid (TSA) in the blood were determined using the thiobarbituric acid method and the white blood cells (WBC) count, haemoglobin concentration and packed cell volumes were assessed using an automated haematological analyser.

RESULTS

The results showed that, in the patients aged > 5 years the level of TSA was significantly elevated (P < 0.05) compared to apparently healthy age-matched controls whereas TSA was slightly lower in patients aged < 5 years compared to controls. The ratio of FSSA to TSA was not different between patients aged > 5 years compared to their age-matched controls whereas FSSA/TSA was significantly elevated (P < 0.05) in patients aged < 5 years compared to their aged-matched controls. The level of FSSA/TSA in the patients aged < 5 years was not correlated with parasite density, white blood cell count, haemoglobin concentration or packed cell volume.

CONCLUSION

We concluded that, metabolism and/or physiology of serum sialo-glycoconjugates is affected by malaria and FSSA is mainly elevated in children < 5 years of age but not among older patients suggesting the possible usefulness of FSSA in the analysis of uncomplicated malaria in under five children.

Neuraminidase1 Inhibitor Protects Against Doxorubicin-Induced Cardiotoxicity via Suppressing Drp1-Dependent Mitophagy

Anthracyclines, such as doxorubicin (DOX), are among the effective chemotherapeutic drugs for various malignancies. However, their clinical use is limited by irreversible cardiotoxicity. This study sought to determine the role of neuraminidase 1 (NEU1) in DOX-induced cardiomyopathy and the potential cardio-protective effects of NEU1 inhibitor oseltamivir (OSE). Male Sprague–Dawley (SD) rats were randomized into three groups: control, DOX, and DOX + OSE. NEU1 was highly expressed in DOX-treated rat heart tissues compared with the control group, which was suppressed by OSE administration. Rats in the DOX + OSE group showed preserved cardiac function and were protected from DOX-induced cardiomyopathy. The beneficial effects of OSE were associated with the suppression of dynamin-related protein 1 (Drp1)-dependent mitochondrial fission and mitophagy. In detail, the elevated NEU1 in cardiomyocytes triggered by DOX increased the expression of Drp1, which subsequently enhanced mitochondrial fission and PINK1/Parkin pathway-mediated mitophagy, leading to a maladaptive feedback circle towards myocardial apoptosis and cell death. OSE administration selectively inhibited the increased NEU1 in myocardial cells insulted by DOX, followed by reduction of Drp1 expression, inhibition of PINK1 stabilization on mitochondria, and Parkin translocation to mitochondria, thus alleviating excessive mitochondrial fission and mitophagy, alleviating subsequent development of cellular apoptotic process. This work identified NEU1 as a crucial inducer of DOX-induced cardiomyopathy by promoting Drp1-dependent mitochondrial fission and mitophagy, and NEU1 inhibitor showed new indications of cardio-protection against DOX cardiotoxicity.

Combined Untargeted and Targeted Metabolomics Approaches Reveal Urinary Changes of Amino Acids and Energy Metabolism in Canine Babesiosis With Different Levels of Kidney Function

Canine babesiosis is a tick-borne disease with a worldwide distribution, caused by the haemoprotozoan parasites of the genus Babesia. One of the most prevalent complication is acute kidney injury, and an early diagnosis of altered kidney function remains a challenge for veterinary practice. The aim of this study was to assess the urine metabolic profile from dogs with babesiosis and different degree of kidney function using untargeted and targeted MS-based metabolomics approaches. In this study, 22 dogs naturally infected with Babesia canis and 12 healthy dogs were included. Untargeted metabolomics approach identified 601 features with a differential abundance between the healthy group and groups of dogs with babesiosis and different level of kidney function, with 27 of them identified as a match to known standards; while targeted approach identified 17 metabolites with significantly different concentrations between the groups. A pattern of significantly altered metabolites referring to the inflammatory host response, oxidative stress, and energy metabolism modulation in babesiosis was presented. Our findings have demonstrated that kidney dysfunction accompanying canine babesiosis was associated with changes in amino acid metabolism, energy metabolism, fatty acid metabolism, and biochemical pathways such as urea cycle and ammonia detoxication. These findings will enable the inclusion of urinary markers for the detection and monitoring of renal damage in babesiosis, as well as in other similar diseases.

Sialic acid as a potential biomarker for cardiovascular disease, diabetes and cancer

Cardiovascular disease (CVD), diabetes and cancer pose increasing global healthcare burdens. New biomarkers could enable earlier diagnosis of these diseases, leading to more effective treatment and lower associated healthcare burden. Elevated sialic acid concentration in plasma and serum has been positively correlated with the presence of CVDs, diabetes and the development of malignant tumors. This article reviews the use of total sialic acid (TSA), bound sialic acid (BSA) and free sialic acid (FSA) as potential biomarkers for these diseases and makes a comparison with existing markers. Elevated sialic acid has been shown to be indicative of the pathogenesis of CVD, diabetes and malignant tumors. While not a specific marker for one disease there is promise in utilizing sialic acid as a marker for monitoring disease progression and effectiveness of treatment programs.

Neuraminidase 1 and its Inhibitors from Chinese Herbal Medicines: An Emerging Role for Cardiovascular Diseases

Neuraminidase, also known as sialidase, is ubiquitous in animals and microorganisms. It is predominantly distributed in the cell membrane, cytoplasmic vesicles, and lysosomes. Neuraminidase generally recognizes the sialic acid glycosidic bonds at the ends of glycoproteins or glycolipids and enzymatically removes sialic acid. There are four types of neuraminidases, named as Neu1, Neu2, Neu3, and Neu4. Among them, Neu1 is the most abundant in mammals. Recent studies have revealed the involvement of Neu1 in several diseases, including cardiovascular diseases, diabetes, cancers, and neurological disorders. In this review, we center the attention to the role of Neu1 in cardiovascular diseases, including atherosclerosis, ischemic myocardial injury, cerebrovascular disease, congenital heart disease, and pulmonary embolism. We also summarize inhibitors from Chinese herbal medicines (CHMs) in inhibiting virus neuraminidase or human Neu1. Many Chinese herbs and Chinese herb preparations, such as Lonicerae Japonicae Flos, Scutellariae Radix, Yupingfeng San, and Huanglian Jiedu Decoction, have neuraminidase inhibitory activity. We hope to highlight the emerging role of Neu1 in humans and potentially titillate interest for further studies in this area.

Evaluation of Serum Levels of Inflammation, Fibrinolysis and Oxidative Stress Markers in Coronary Artery Disease Prediction: A Cross-Sectional Study

Background

Coronary Artery Disease (CAD) has long been recognized as a global health issue. Inflammation, Fibrinolysis and Oxidative Stress play an important role in the disruption of plaques leading to CAD. Markers that reflect this pathophysiologic mechanism may have prognostic value.

Objective

To estimate the serum concentrations of high-sensitivity C-reactive protein (hs-CRP), sialic acid (SA), vitronectin (VN), plasminogen activator inhibitor-1 (PAI-1), oxidized low density lipoprotein (OX-LDL) and malondialdehyde (MDA) with significant prognostic value in patients with CAD.

Methods

The markers included, hs-CRP, SA, VN, PAI-1, OX-LDL and MDA, were compared between 160 angiographically diagnosed CAD patients and 20 age- and sex-matched healthy individuals. The subjects were divided into 4 groups according to angiography results, and association between all risk factors of CAD was studied. Serum levels of SA, VN, PAI-1, and OX-LDL were measured by enzyme-linked immunosorbent assay (ELISA); MDA was measured based on reaction with thiobarbituric acid (TBA); and hs-CRP level was estimated by immunoturbidimetry using a commercial kit. The diagnostic value of these variables was further assessed by ROC curve analysis. Multiple logistic regression was used to evaluate the diagnostic power of the combination. Furthermore, p < 0.05 was considered as significant.

Results

Serum levels of hs-CRP, SA, VN, PAI-1, and OX-LDL were significantly higher in patient groups compared to control group (p < 0.001). Using both normal and CAD patients as subjects, ROC analysis was performed. The cutoff for OX-LDL, MDA, PAI-1, VN, hs-CRP and SA was 2.67 (ug/mL), 5.49 (mmol/mL), 67 (ng/mL), 254 (ng/mL), 3.4 (mg/dL), 7/89 (mg/dL), respectively. Eventually, the complete diagnostic efficacy was classified as: SA, hs-CRP, PAI-1, OX-LDL, MDA and VN.

Conclusion

Serum levels SA, hs-CRP, VN, PAI-1, OX-LDL and MDA may be predictive of adverse cardiovascular outcomes. Interestingly, these analyses can help as diagnostic and monitoring markers in CAD patients.

Effectiveness of influenza and pneumococcal polysaccharide vaccines against influenza-related outcomes including pneumonia and acute exacerbation of cardiopulmonary diseases: Analysis by dominant viral subtype and vaccine matching

Background

Influenza and pneumonia are leading causes of morbidity and mortality among the elderly. Although vaccination is a main strategy to prevent these infectious diseases, concerns remain with respect to vaccine effectiveness.

Methods

During three influenza seasons (2014–2015, 2015–2016 and 2016–2017), we evaluated the effectiveness of the influenza and pneumococcal vaccines against pneumonia and acute exacerbation of cardiopulmonary diseases among the elderly aged ≥65 years with influenza-like illness (ILI). Demographic and clinical data were collected prospectively.

Results

Among 2,119 enrolled cases, 1,302 (61.4%) and 871 (41.1%) received the influenza vaccine and 23-valent pneumococcal polysaccharide vaccine (PPV23), respectively. During an A/H3N2-dominant season with poor influenza vaccine effectiveness (2014–2015 season), neither the influenza vaccine nor PPV23 showed significant effectiveness against pneumonia or acute exacerbation of cardiopulmonary diseases. During seasons with good influenza vaccine effectiveness (2015–2016 and 2016–2017 seasons), the influenza vaccine was effective in preventing pneumonia, but PPV23 was not. In particular, the influenza vaccine was effective in preventing acute exacerbation of heart diseases (75.0%) during the A/H1N1-dominant 2015–2016 season.

Conclusion

The influenza vaccine was effective in preventing pneumonia only during vaccine-matched seasons with good effectiveness against circulating influenza viruses. In addition, the influenza vaccine was cardio-protective during a vaccine-matched A/H1N1-dominant season.

Plasma Myeloperoxidase and Total Sialic Acid as Prognostic Indicators in Acute Coronary Syndrome

INTRODUCTION

Acute Coronary Syndrome (ACS) is the leading cause of death worldwide. Oxidative stress and inflammation play important role in the destabilization of plaques leading to ACS. Markers which reflect this pathophysiologic mechanism may have prognostic value. Myeloperoxidase (MPO) and Sialic acid are markers of inflammation and oxidative stress. Both these markers are increased in patients with ACS. Their prognostic value in ACS is not well established.

AIM

To analyse the prognostic value of plasma myeloperoxidase and total sialic acid levels in patients with suspected acute coronary syndrome.

MATERIALS AND METHODS

A prospective study was conducted on 93 consecutively admitted patients with chest pain from July 2011 to September 2011. Plasma MPO and total sialic acid levels on admission were estimated spectrophotometrically. These were compared with extent of disease, development of complications during the hospital stay, left ventricular ejection fraction and mean duration of stay in hospital.

RESULTS

Plasma MPO and total sialic acid levels were significantly higher in patients with myocardial infarction than those with unstable and stable angina (p<0.001 and p<0.007 respectively). The levels of plasma MPO and sialic acid levels were significantly higher in patients who developed complications like heart failure, arrhythmias, renal failure during their stay in hospital (p<0.011 and p<0.006 respectively). Ejection fraction was significantly low in patients with high MPO levels (p<0.011).

CONCLUSION

In patients with ACS, plasma MPO and total sialic acid levels on admission could predict the development of complications during their hospital stay. MPO levels correlated with ejection fraction in patients with ACS.

Protective effect of S-allyl cysteine sulphoxide (alliin) on glycoproteins and hematology in isoproterenol induced myocardial infarction in male Wistar rats

The antihyperlipidemic, antilipoperoxidative and antioxidant effects of S-allyl cysteine sulphoxide (SACS) in myocardial infarcted rats were reported previously. The present study was undertaken to evaluate the preventive role of SACS on some biochemical parameters, glycoproteins and hematology in experimentally induced myocardial infarction in rats. Myocardial infarction was induced in rats by subcutaneous injection of isoproterenol (ISO) (150 mg kg(-1)) at an interval of 24 h for 2 days. ISO-treated rats showed a significant increase in the levels of serum iron, uric acid and blood glucose, Na(+) and Ca(2+) in the heart and a significant decrease in the levels of plasma iron binding capacity, serum total protein, albumin/globulin ratio, heart K(+) and heart glycogen. The levels/concentrations of glycoproteins in serum and the heart were increased in myocardial infarcted rats. Myocardial infarcted rats also showed a significant increase in red blood cells, hemoglobin, packed cell volume, white blood cells, neutrophils, platelet count and fibrinogen level and a significant decrease in erythrocyte sedimentation rate, eosinophils, lymphocytes, bleeding, clotting and prothrombin time. Oral pretreatment with SACS (40 and 80 mg kg(-1)) daily for a period of 35 days showed a positive effect on all the biochemical parameters studied in ISO-induced rats. Thus, the study showed the protective effect of SACS on ISO-induced cardiotoxicity in male Wistar rats.

Sialic acid and oxidizability of lipid and proteins and antioxidant status in patients with coronary artery disease

The aim of this study was to investigate the possible relationship between serum total sialic acid (TSA) concentration, recently shown to be a cardiovascular risk factor, and lipid and protein oxidation and antioxidant status and the severity of coronary artery disease (CAD) according to the obstructive vessel number in patients. The study was carried out on a total of 200 patients (142 men and 58 women) who were hospitalized for elective coronary angiographic evaluation with complaint of typical angina pectoris. According to the results of angiography, 150 patients had angiographically proven CAD (CAD group) and 50 patients had a history suggestive of angina pectoris but normal coronary angiograms (control group). The CAD group was further divided into single-, double- and triple-vessel disease groups according to the number of vessels involved. Lipid parameters were determined by routine laboratory methods. Plasma malondialdehyde (MDA) and vitamin E concentrations were determined by high-performance liquid chromatography. TSA and other oxidant and antioxidant parameters were studied spectrophotometrically. Our results demonstrated significant increases both in TSA levels and in indicators of oxidative stress in the patients with CAD compared with the controls. However, antioxidant parameters were decreased in the patients with CAD. We found strong positive correlations between TSA and plasma MDA, Delta-MDA which represents the degree of oxidative modification of apolipoprotein B-containing lipoproteins, serum protein carbonyls and apolipoprotein B and weak correlations between TSA and low density lipoprotein cholesterol, triacylglycerol, paraoxonase, glutathione peroxidase (GPx), vitamin C and vitamin E. In conclusion, TSA is related to markers of lipid and protein oxidation, paraoxonase and GPx activities, vitamin C and E levels and the severity of CAD.

Sialic acid: a novel marker of cardiovascular disease?

The global burden posed by cardiovascular disease (CVD), due to a rising incidence of known risk factors, underlines an urgent need to identify other potential risk factors. Sialic acid (SA), an abundant terminal monosaccharide of glycoconjugates, is a possible risk factor for CVD. Although large-scale epidemiological surveys have shown that serum total sialic acid (TSA) is positively associated with mortality from coronary artery disease (CAD) and stroke, studies investigating the correlation between serum TSA and the severity of atherosclerosis are conflicting. Clinical and epidemiological studies indicate that serum TSA is a marker of a sustained inflammatory response in CVD, rather than causal in nature. Data also indicates ethnic variation in baseline TSA. This article reviews current methods for determining serum TSA and evidence supporting serum TSA as a risk factor for CVD. Potential mechanisms for this role are examined. The use of serum TSA as a marker of atherosclerotic disease is evaluated.

Sialic acid in cardiovascular diseases

Sialic acid, the acylated derivatives of 9-carbon sugar neuraminic acid, present as terminal component of oligosaccharide chains of many glycoproteins and glycolipids, has been recognized to be involved in the regulation of a great variety of biological phenomena. Studies have shown that serum sialic acid predicts both coronary heart disease and stroke mortality and reflects the existence or activity of an atherosclerotic process. Most of the studies have shown an elevation in serum sialic acid concentration in coronary heart disease and a positive correlation between the raised serum sialic acid and the severity of the coronary lesions is observed. However, a few contradictory reports are also available. Racial differences in serum sialic acid have also been reported and correlated with international differences in the prevalence of atherosclerosis. Reduced sialic acid content of platelets, erythrocytes and lipoproteins may play important role in the pathogenesis of atherosclerosis. Elucidation of the mechanism of alternation in sialic acid concentration may throw more light on its potential clinical utility. Hence more studies are needed to designates sialic acid as a cardiovascular risk factor/marker.

Serum total ganglioside level correlates with clinical course in melanoma patients after immunotherapy with therapeutic cancer vaccine

The authors tested the hypothesis that the therapeutic destruction of residual tumors may be reflected in the level of serum total gangliosides (sTG). The sTG level was evaluated in 17 patients with in-transit melanoma and 70 patients with resected regional node metastasis, who have received a polyvalent therapeutic melanoma cell vaccine. The treatment response was determined by regression of in-transit metastases or by overall survival after resection. sTG levels were measured, blinded, before and after immunotherapy. The mean sTG level of the in-transit melanoma patients increased from 18.57 +/- 3.18 mg/dL pretreatment to 23.7 +/- 5.5 mg/dL between weeks 2 and 16 after initiation of treatment (p(2) < 0.0001). By week 24, the level had returned to its prevaccine level in the seven clinical responders (18.1 +/- 2.3 mg/dL vs. 20.4 +/- 3.2 mg/dL; p(2) < 0.050) but remained higher than its prevaccine level in the 10 nonresponders (23.3 +/- 5.1 mg/dl vs. 17.2 +/- 2.7 mg/dL). Similarly, the sTG level of the patients with nodal metastases increased between weeks 2 and 16 after the first vaccine treatment; by week 24, it had returned to pretreatment level in patients who survived more than 56 weeks but remained significantly elevated (p(2) < 0.01) in patients who survived less than 56 weeks. The sTG level increased between weeks 2 and 16 in all vaccine recipients and returned to prevaccine level by week 24 in all who showed measurable regression of in-transit melanoma (7 of 17 patients) or improved overall survival (53 of 70 patients). The data suggest that sTG level could be a potential tool for assessing the response to immunotherapy in melanoma patients by week 24.

Association between inflammation and hemostatic markers in atherothrombotic stroke

INTRODUCTION

It has been reported that the influence of fibrinogen on the incidence of ischemic events is related to inflammation processes and reflects an association with advance atherosclerosis. The aim of this study was to evaluate the association of thrombogenic and inflammatory profiles in patients who have suffered a stroke.

MATERIALS AND METHODS

The study involved 17 patients with atherothrombotic stroke and 34 healthy subjects as control group. The patients were examined 48 h, 3 and 6 months after the stroke occurred. To determine the inflammatory and thrombogenic profiles, plasma levels of fibrinogen, total sialic acid (TSA), C-reactive protein (CRP), tissue factor (TF) and fibrin D-dimer (D-dimer) were measured.

RESULTS

The study showed that at 48 h and 3 months the levels of fibrinogen, TF, D-dimer, TSA and CRP were significantly higher than control group. TF, D-dimer and TSA remains significantly elevated throughout the entire study period. TF and D-dimer decreased over time without reaching the normal values. The multiple regression analysis showed that, at 48 h, 68% of the variance of fibrinogen and 22% of the variance of TF could be explained by the influence of CRP. At 3 and 6 months, 78% of the variance of fibrinogen could be explained by the influence of TSA.

CONCLUSIONS

The results suggest a relation among inflammation markers, fibrinogen and TF in the acute phase of stroke. As TF and D-dimer are still elevated at 6 months, an increased thrombogenicity for a longer period following the acute event is present.

A capillary zone electrophoresis method for determining N-acetylneuraminic acid in glycoproteins and blood sera

A simple capillary zone electrophoresis (CZE) method for the determination of the content of the major sialic acid form N-acetylneuraminic acid (Neu5Ac) in glycoproteins was established. The present method utilizes a simplified hydrolysis-purification procedure consisting of mild acid hydrolysis (25 mM trifluoroacetic acid for 2h at 80 degrees C) to release Neu5Ac and ultrafiltration on Centricon-3 membrane to remove the obtained asialoglycoproteins and other macromolecules present in biologic samples. Derivatization with benzoic anhydride at 80 degrees C for 20 min resulted in complete conversion of Neu5Ac to per-O-benzoylated Neu5Ac. CZE analysis was performed using the operating buffer 25mM phosphate, pH 3.5, containing 50% (v/v) acetonitrile as organic modifier at 30 kV, and detection of the per-O-benzoylated Neu5Ac at 231 nm. The method showed excellent repeatability (RDS<1.98%) and a linearity range from 5 microg/mL to 5mg/mL with a detection limit of 2 microM. Application of the method to microanalysis of human alpha(1)-acid glycoprotein and blood serum samples showed excellent agreement with previously published values, suggesting a high precision for the developed CZE method.