Ceramides-Emerging Biomarkers of Lipotoxicity in Obesity, Diabetes, Cardiovascular Diseases, and Inflammation.

Abnormalities in lipid homeostasis have been associated with many human diseases, and the interrelation between lipotoxicity and cellular dysfunction has received significant attention in the past two decades. Ceramides (Cers) are bioactive lipid molecules that serve as precursors of all complex sphingolipids. Besides their function as structural components in cell and mitochondrial membranes, Cers play a significant role as key mediators in cell metabolism and are involved in numerous cellular processes, such as proliferation, differentiation, inflammation, and induction of apoptosis. The accumulation of various ceramides in tissues causes metabolic and cellular disturbances. Recent studies suggest that Cer lipotoxicity has an important role in obesity, metabolic syndrome, type 2 diabetes, atherosclerosis, and cardiovascular diseases (CVDs). In humans, elevated plasma ceramide levels are associated with insulin resistance and impaired cardiovascular and metabolic health. In this review, we summarize the role of ceramides as key mediators of lipotoxicity in obesity, diabetes, cardiovascular diseases, and inflammation and their potential as a promising diagnostic tool.

Assessment of health status and cardiovascular risk factors in a Roma population sample from South Bulgaria.

OBJECTIVES: Roma population is one of the major ethnic groups in the Central and Eastern Europe, having high rates of chronic diseases and associated risk factors related to their poor social conditions, unhealthy lifestyle and low educational level. The purpose of our study was to assess the health status of Roma from South Bulgaria by means of blood indicators and determine the prevalence of some cardiovascular (CV) risk factors in the Roma population sample. METHODS: The study group consisted of 60 Roma (23 men and 37 women), mean age 53.7 ± 15.9 years, and the control group consisted of 68 non-Roma from the majority population (29 men and 38 women), mean age 45.8 ± 12.2 years. The data were collected via questionnaire, anthropometric measures, and venous blood samples analyses after an overnight fasting. RESULTS: The Roma population subjects were slightly but significantly older compared to the non-Roma group and both study groups included more women. The fasting glucose, body mass index (BMI), triglycerides (TG), total cholesterol (TC), and LDL-cholesterol (LDL-C) levels were significantly higher, and HDL-cholesterol (HDL-C) levels were significantly lower in Roma compared to the control non-Roma group. The values of cardiovascular risk markers such as TC/HDL-C and TG/HDL-C ratios, atherogenic index of plasma (AIP) and lipoprotein combine index (LCI) were significantly higher in Roma compared to non-Roma subjects. The prevalence of obesity in Roma was 35%, diabetes mellitus was recorded in 16.7% of the entire Roma sample, and hyperglycaemia in non-diabetics was recorded in 32%. Hypercholesterolaemia was found in 90% and hypertriglyceridaemia was found in 88.3%. The prevalence of cardiovascular diseases (CVD) was high and was encountered in 71.7% of the Roma participants and most of the subjects (96.7%) reported family history of CVD. The studied population showed high smoking rates with 33.3% active smokers. CONCLUSIONS: Our study confirmed high prevalence of CV risk factors among Roma population, such as abnormal lipid profile parameters, obesity and heavy smoking and very high cardiovascular morbidity rate. Therefore, adequate measures and healthcare programmes aiming at the early identification, treatment and prevention of CVD risks among Roma are necessary.

Rheumatoid arthritis and the proinflammatory cytokine IL-17.

INTRODUCTION: Rheumatoid arthritis (RA) is the most common inflammatory joint disease. Various proinflammatory cytokines are involved in the pathogenesis of this chronic disorder. It is characterized by the presence of autoantibodies, such as rheumatoid factor and antibodies against citrullinated peptides. The present study focuses on investigation of possible association between the proinflammatory cytokine interleukin 17 and anti-CCP, anti-MCV, and anti-CarP antibodies seropositivity in RA patients. AIM: To assess serum levels of interleukin 17 (IL-17) in patients with rheumatoid arthritis and healthy controls (HC) and to investigate the relationship between IL-17 and anti-cyclic citrullinated protein (anti-CCP) antibodies, antimutated citrullinated vimentin (anti-MCV) antibodies, and anti-carbamylated protein (anti-CarP) antibodies in patients with RA. MATERIALS AND METHODS: Forty-seven patients diagnosed with rheumatoid arthritis and 44 healthy controls were included in the study. Serum IL-17 levels were examined in all participants. Anti-CCP, anti-MCV, and anti-CarP antibodies were tested in the group of RA patients. RESULTS: The mean serum level of IL-17 in RA patients was higher (12.8 pg/ml) than that in healthy controls (7.9 pg/ml), but the difference was not statistically significant (p=0.276). No significant correlation was observed between anti-CCP (+/-) and IL-17 (rs=0.162, p=0.380), and between anti-MCV (+/-) and IL-17 (rs=0.157, p=0.340). A significant positive correlation of moderate value was reported between anti-CarP (+/-) and IL-17 (rs=0.388, p=0.015). CONCLUSIONS: The present study demonstrated that the IL-17 serum levels in RA patients were increased compared to healthy controls. No correlation was found between ACPA immunological markers and IL-17 levels in patients with RA. A positive correlation was found between anti-CarP antibodies and IL-17 in the patients' group. The increased level of IL-17 is suggestive of its possible role in the pathogenesis of CarP positive RA patients.

Drug-neutralizing Antibodies against TNF-α blockers as Biomarkers of Therapy Effect Evaluation.

INTRODUCTION: TNF-α blocker therapy is part of the treatment with biologics used in the management of inflammatory joint diseases. In recent years, drug-induced neutralizing antibodies have been shown to have a negative effect on the course of the disease process. AIM: To investigate drug-induced neutralizing antibodies against TNF-α blocking drugs used in patients with inflammatory joint diseases and their effect on the clinical course of the disease. MATERIALS AND METHODS: The study included 121 (56.8%) patients with rheumatoid arthritis, 50 (23.5%) patients with ankylosing spondylitis, 42 (19.7%) patients with psoriatic arthritis, and 31 sex and age-matched healthy controls. The patients were monitored at 0, 6, 12, and 24 months after initiation of TNF-α blocker treatment. The demographic data, vital signs and the parameters of inflammatory activity (C-reactive protein, erythrocyte sedimentation rate, and disease activity indices) were analyzed in all patients. Drug-induced anti-TNF-α blockers antibodies (adalimumab and etanercept) were analyzed using ELISA. Statistical analysis was performed with SPSS v. 24. RESULTS: Drug-induced neutralizing antibodies against adalimumab were obtained in 11.57% of patients at 6 month, in 17.64% at 12 month, and in 24.8% at 24 month. Drug-induced neutralizing antibodies to etanercept were not demonstrated in patients followed up at 6 months, at 7.77% at 12 months, and at 9.63% at 24 months. Between the presence of neutralizing antibodies to blockers of TNF-α and indices available for disease activity, there is a strong positive correlation and Pearson Correlation = 0.701, p=0.001. Patients with poor clinical response and available antibodies against adalimumab at 12 months were 82.36% and patients treated with etanercept 71.42%. The difference between the two groups was non-significant (U = 0.527, p> 0.05). Patients with poor clinical response and available anti-adalimumab antibodies at 24 month were 75%, and in patients treated with etanercept - 87.50%, the difference between the two groups not being able to reach significance (U = 0.623, p> 0.05). CONCLUSION: Drug-induced neutralizing antibodies against TNF-α blockers (adalimumab and etanercept) have a negative effect on the course of inflammatory joint disease and can be used as reliable biomarker to assess the effect of the treatment with these drugs.

Serum Levels of Carbamylated LDL and Soluble Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 Are Associated with Coronary Artery Disease in Patients with Metabolic Syndrome.

Background and objectives: Lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) has been recognized as the primary receptor for carbamylated low-density lipoproteins (cLDL) and is increasingly being viewed as a critical mediator of vascular inflammation and atherosclerosis. The aim of the current study was to evaluate the possible role of circulating cLDL and soluble LOX-1 (sLOX-1) as potential biomarkers of metabolic syndrome (MetS) as well as of coronary artery disease (CAD) among MetS patients. Materials and Methods: The serum levels of cLDL and sLOX-1 were measured by ELISA in 30 MetS patients without CAD, 30 MetS patients with CAD, and 30 healthy controls. Results: Patients with MetS had significantly higher serum levels of both cLDL and sLOX-1 than the healthy controls but lower in comparison to MetS + CAD subjects. Serum sLOX-1 concentration correlated significantly with fasting glucose (rs = 0.414, p = 0.001) and high-density lipoprotein (HDL)-cholesterol (rs = -0.273, p = 0.035) in the whole MetS cohort, whereas it correlated with cLDL only in the MetS + CAD subgroup (rs = 0.396, p = 0.030). The receiver-operating characteristic (ROC) curves of cLDL and sLOX-1 for MetS diagnosis had area under the curve (AUC) values of 0.761 and 0.692, respectively. AUC values of cLDL and sLOX-1 for CAD diagnosis among MetS patients were 0.811 and 0.739. Elevated serum levels of cLDL and sLOX-1 were associated with a higher risk of MetS development [odds ratio (OR) 24.28, 95% confidence interval (CI): 5.86-104.61, p < 0.001 and OR 4.75; 95% CI: 1.58-14.25, p = 0.009] as well as with presence of CAD among MetS subjects (OR 11.23; 95% CI: 3.10-40.71, p < 0.001 and OR 4.03; 95% CI: 1.73-11.84, p = 0.019, respectively). Conclusions: The present study underscores the potential of cLDL and sLOX-1 as promising biomarkers for diagnosis and risk assessment of MetS and CAD among the MetS population.

Serum Levels of Carbamylated LDL, Nitrotyrosine and Soluble Lectin-like Oxidized Low-density Lipoprotein Receptor-1 in Poorly Controlled Type 2 Diabetes Mellitus.

INTRODUCTION: Carbamylated low-density lipoprotein (cLDL) has profound proatherogenic properties. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has been identified as the primary cLDL receptor. The soluble form of LOX-1 (sLOX-1) and 3-nitrotyrosine (NT) have recently been suggested as biomarkers of vascular disease. Although type 2 diabetes mellitus (T2DM) is characterised by an increased atherosclerotic risk, the clinical data on cLDL, NT and sLOX-1 levels in T2DM are limited. AIM: To explore the possible role of cLDL, NT and sLOX-1 as potential biomarkers for disease progression and complications in poorly controlled T2DM patients with and without microalbuminuria. MATERIALS AND METHODS: The serum concentrations of cLDL, NT and sLOX-1 were measured by ELISA in a cross-sectional study of 60 T2DM patients and 35 nondiabetic controls. RESULTS: Both the normoalbuminuric (n = 34) and the microalbuminuric (n = 26) patients had significantly higher serum levels of cLDL and NT than the healthy controls, but sLOX-1 was only elevated in the microalbuminuric subgroup (p < 0.05). Carbamylated LDL correlated positively with NT in the diabetic subjects (rs = 0.266, p = 0.04) while it correlated with urea only in the control group (rs = 0.475, p = 0.004). The serum concentration of sLOX-1 correlated significantly with fasting glucose (rs = 0.441, p < 0.001), HbA1c (rs = 0.328, p = 0.01) and microalbuminuria (rs = 0.272, p = 0.035) in the whole diabetic cohort. CONCLUSIONS: The present study highlights the potential of cLDL, NT and sLOX-1 as possible markers of diabetic complications.

Pathobiochemical Mechanisms Relating Iron Homeostasis with Parameters of Inflammatory Activity and Autoimmune Disorders in Rheumatoid Arthritis.

AIM: To find the correlations between the parameters of iron homeostasis, inflammatory activity and autoimmune disorders in rheumatoid arthritis (RA). MATERIALS AND METHODS: The present study included 114 patients with RA and 42 healthy controls. We determined the parameters of iron homeostasis: serum iron, total iron binding capacity (TIBC), ferritin and soluble transferrin receptor (sTfR), the parameters of inflammatory activity: C-reactive protein (CRP), interleukin-6 (IL-6) and prohepcidin, and the parameters of autoimmune disorders: rheumatoid factor (RF), anti-cyclic citrullinated peptide (antiCCP) antibodies and DAS 28. RESULTS: The levels of sTfR, CRP, IL-6 and prohepcidin were significantly higher in RA patients than those in the controls and the level of serum iron was significantly lower in RA than that in the control group. Unlike the controls, in RA, there was a significant positive correlation of sTfR with the parameters of inflammatory activity (IL-6, prohepcidin, ESR) and with the parameters of autoimmune disorders (DAS 28, RF, antiCCP). A negative correlation of serum iron with sTfR was found only in RA patients. Prohepcidin positively correlated with the parameters of inflammation (CRP, ESR) and with the parameters for evaluation of autoimmune disorders (DAS 28 and RF) in the RA group. CONCLUSION: Our study shows that the simultaneous determination of the two parameters sTfR and prohepcidin is most informative for evaluation of the changes in iron homeostasis in RA. The increase of both parameters provides information for tissue iron deficiency (assessed by the level of sTfR), caused by the inflammation when prohepcidin is expressed.

Pathobiochemical Mechanisms Relating Iron Homeostasis to Parameters of Inflammatory Activity and Autoimmune Disorders in Rheumatoid Arthritis.

AIM: To find the correlations between the parameters of iron homeostasis, inflammatory activity and autoimmune disorders in rheumatoid arthritis (RA). MATERIALS AND METHODS: The present study included 114 patients with RA and 42 healthy controls. We determined the parameters of iron homeostasis: serum iron, total iron binding capacity (TIBC), ferritin and soluble transferrin receptor (sTfR), the parameters of inflammatory activity: C-reactive protein (CRP), interleukin-6 (IL-6) and prohepcidin, and the parameters of autoimmune disorders: rheumatoid factor (RF), anti-cyclic citrullinated peptide (antiCCP) antibodies, and DAS 28. RESULTS: The levels of sTfR, CRP, IL-6 and prohepcidin were significantly higher in RA patients than those in the controls and the level of serum iron was significantly lower in RA than that in the control group. Unlike the controls, in RA, there was a significant positive correlation of sTfR with the parameters of inflammatory activity (IL-6, prohepcidin, ESR) and with the parameters of autoimmune disorders (DAS 28, RF, antiCCP). A negative correlation of serum iron with sTfR was found only in RA patients. Prohepcidin positively correlated with the parameters of inflammation (CRP, ESR) and with the parameters for evaluation of autoimmune disorders (DAS 28 and RF) in the RA group. CONCLUSION: Our study shows that the simultaneous determination of the two parameters sTfR and prohepcidin is most informative in evaluating the changes in iron homeostasis in RA. The increase of both parameters provides information for tissue iron deficiency (assessed by the level of sTfR), caused by the inflammation when prohepcidin is expressed.