Increased levels of antibodies to cytokeratin 18 in patients with rheumatoid arthritis and ischaemic heart disease

Cytokeratin 18 as a Novel Biomarker in Patients with Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a heart muscle disease associated with an increased risk for sudden cardiac death (SCD). Cytokeratin 18-based proteins, such as M30 and M65 antigens, are known cell-death biomarkers. M30 antigen is released from cells during apoptosis, and M65 antigen is released during cell death from any cause, such as apoptosis or necrosis. We aimed to study the expression of M30 and M65 antigens in peripheral blood obtained by 46 HCM patients and compare with 27 age- and sex-matched patients without HCM. We also investigated the CK18 expression in myocardium from postmortem HCM hearts. M30 and M65 antigens were significantly increased in the HCM vs. non-HCM group (Μ30: 338 ± 197 U/uL vs. 206 ± 166 U/uL, p = 0.003; M65: 428 ± 224 U/uL vs. 246 ± 214 U/uL, p = 0.001), and HCM patients with a higher expression of these markers (M30: 417 ± 208 vs. 271 ± 162 U/uL, p = 0.011; M65: 518 ± 242 vs. 351 ± 178 U/uL, p = 0.011) had a higher risk for SCD. In HCM, both apoptosis and necrosis are increased, but particularly necrosis (M30/M65 ratio: 0.75 ± 0.09 vs. 0.85 ± 0.02, p < 0.001). CK18 is expressed in the HCM myocardium (1.767 ± 0.412 vs. 0.537 ± 0.383, % of area, p = 0.0058). Therefore, M30 and M65 antigens may be novel biomarkers in HCM.

Comparative study of cardio-protective effects of zinc oxide nanoparticles and zinc sulfate in streptozotocin-induced diabetic rats

The cardio-protective effects of zinc oxide nanoparticles (Zn NPs) against diabetes-induced cardiopathy were evaluated and compared with zinc sulfate (ZnSO₄). A total of 120 Wistar rats were randomly categorized as healthy and diabetic groups. Then, the 2 groups were classified in 5 subgroups. The animals received oral supplementations containing different Zn NP (ie, doses of 1, 3, and 10mg/kg) and ZnSO₄ (30mg/kg) concentrations over 8 weeks. Blood and cardiac tissue samples were collected in the different time intervals and subjected to biochemical and histopathological analysis. Zn NPs showed dual effects, as its middle dose played protective role and recovered cardiac damages evidenced by significant reduction of serum cholesterol, HDL-cholesterol, lipoprotein (a), atherogenic index, TNF-α, cardiac MDA, B-type natriuretic peptide and caspase-3 activity. Apoptosis indices and histopathological features also were improved. However, the highest dose was found to be toxic and resulted in aggravation of the injuries. Another interesting finding is the ability of the higher doses of Zn-NPs (3 and 10mg/kg) to elevate cardiac zinc levels above the normal range in healthy animal. ZnSO₄ also helped to recuperation of the damages, but the middle dose of Zn NPs was more efficient as compared to ZnSO₄. Conclusively, Zn NPs have the potential for Zn delivery in diabetic patients.

Muscle wasting in rheumatoid arthritis: The role of oxidative stress

Rheumatoid arthritis (RA), the commonest inflammatory arthritis, is a debilitating disease leading to functional and social disability. In addition to the joints, RA affects several other tissues of the body including the muscle. RA patients have significantly less muscle mass compared to the general population. Several theories have been proposed to explain this. High grade inflammation, a central component in the pathophysiology of the disease, has long been proposed as the key driver of muscle wasting. More recent findings however, indicate that inflammation on its own cannot fully explain the high prevalence of muscle wasting in RA. Thus, the contribution of other potential confounders, such as nutrition and physical activity, has also been studied. Results indicate that they play a significant role in muscle wasting in RA, but again neither of these factors seems to be able to fully explain the condition. Oxidative stress is one of the major mechanisms thought to contribute to the development and progression of RA but its potential contribution to muscle wasting in these patients has received limited attention. Oxidative stress has been shown to promote muscle wasting in healthy populations and people with several chronic conditions. Moreover, all of the aforementioned potential contributors to muscle wasting in RA (i.e., inflammation, nutrition, and physical activity) may promote pro- or anti-oxidative mechanisms. This review aims to highlight the importance of oxidative stress as a driving mechanism for muscle wasting in RA and discusses potential interventions that may promote muscle regeneration via reduction in oxidative stress.

Effects of Off-Pump Versus On-Pump Coronary Artery Bypass Grafting: Apoptosis, Inflammation, and Oxidative Stress

<strong>Background</strong>: It has been suggested that off-pump coronary<br />artery bypass grafting (CABG) surgery reduces myocardial<br />ischemia-reperfusion injury, postoperative systemic<br />inflammatory response, and oxidative stress. The aim of this<br />study was to measure serum malondialdehyde (MDA), highsensitivity<br />C-reactive protein (hs-CRP), M30, and M65 levels<br />and to investigate the relationship between M30 levels and<br />oxidative stress and inflammation in patients undergoing onand<br />off-pump CABG surgery.<br /><strong>Methods</strong>: Fifty patients were randomly assigned to onpump<br />or off-pump CABG surgery (25 patients off-pump and<br />25 on-pump CABG surgery), and blood samples were collected<br />prior to surgery, and 30 minutes, 60 minutes, 6 hours,<br />and 24 hours after CABG surgery.<br /><strong>Results</strong>: Compared to the on-pump group, serum MDA<br />levels at 30 minutes, 60 minutes, 6 hours, and 24 hours after<br />the CABG surgery were significantly lower in the off-pump<br />group (P = .001, P = .001, P = .001, and P = .001, respectively).<br />Serum M30 levels were found to be elevated in both groups,<br />returning to baseline at 24 hours. When compared to baseline,<br />the hs-CRP level reached its peak at 24 hours at 13.28 ±<br />5.32 mg/dL in the on-pump group, and 15.44 ± 4.02 mg/dL<br />in the off-pump group.<br /><strong>Conclusion</strong>: CABG surgery is associated with an increase<br />in inflammatory markers and serum M30 levels, indicating<br />epithelial/endothelial apoptosis in the early period.

Cardiovascular involvement in autoimmune diseases

Autoimmune diseases (AD) represent a broad spectrum of chronic conditions that may afflict specific target organs or multiple systems with a significant burden on quality of life. These conditions have common mechanisms including genetic and epigenetics factors, gender disparity, environmental triggers, pathophysiological abnormalities, and certain subphenotypes. Atherosclerosis (AT) was once considered to be a degenerative disease that was an inevitable consequence of aging. However, research in the last three decades has shown that AT is not degenerative or inevitable. It is an autoimmune-inflammatory disease associated with infectious and inflammatory factors characterized by lipoprotein metabolism alteration that leads to immune system activation with the consequent proliferation of smooth muscle cells, narrowing arteries, and atheroma formation. Both humoral and cellular immune mechanisms have been proposed to participate in the onset and progression of AT. Several risk factors, known as classic risk factors, have been described. Interestingly, the excessive cardiovascular events observed in patients with ADs are not fully explained by these factors. Several novel risk factors contribute to the development of premature vascular damage. In this review, we discuss our current understanding of how traditional and nontraditional risk factors contribute to pathogenesis of CVD in AD.

Heart involvement in rheumatoid arthritis: multimodality imaging and the emerging role of cardiac magnetic resonance

OBJECTIVES

Patients with rheumatoid arthritis (RA) exhibit a high risk of cardiovascular disease (CVD). CVD in RA can present in many guises, commonly detected at a subclinical level only.

METHODS

Modern imaging modalities that allow the noninvasive assessment of myocardial performance and are able to identify cardiac abnormalities in early asymptomatic stages may be useful tools in terms of screening, diagnostic evaluation, and risk stratification in RA.

RESULTS

The currently used imaging techniques are echocardiography, single-photon emission computed tomography (SPECT), and cardiac magnetic resonance (CMR). Between them, echocardiography provides information about cardiac function, valves, and perfusion; SPECT provides information about myocardial perfusion and carries a high amount of radiation; and CMR-the most promising imaging modality-evaluates myocardial function, inflammation, microvascular dysfunction, valvular disease, perfusion, and presence of scar. Depending on availability, expertise, and clinical queries, "right technique should be applied for the right patient at the right time."

CONCLUSIONS

In this review, we present a short overview of CVD in RA focusing on the clinical implication of multimodality imaging and mainly on the evolving role of CMR in identifying high-risk patients who could benefit from prevention strategies and early specific treatment targeting the heart. Advantages and disadvantages of each imaging technique in the evaluation of RA are discussed.

Obesity in rheumatoid arthritis

Obesity is a major threat for public health and its study has attracted significant attention in the general population, predominantly due to its association with significant metabolic and cardiovascular complications. In RA research, BMI is frequently reported as a demographical variable, but obesity, as such, has received little interest. This is surprising, in view of the clear associations of obesity with other arthritides, particularly OA, but also in view of the now-clear association of RA with increased cardiovascular morbidity and mortality. In this review, we summarize the studies that have looked into obesity in the RA population, evaluate their findings, identify knowledge gaps and propose directions for future research. We also pose a question of high clinical and research significance: is the use of BMI still a valid way of assessing obesity in RA?

Serial changes in circulating M30 antigen, a biomarker of apoptosis, in patients with acute coronary syndromes: relationship with the severity of coronary artery disease

OBJECTIVES

Growing evidence has indicated the potential clinical usefulness of measuring different forms of cytokeratin 18 in patient sera (M30 antigen for apoptosis and M65 antigen for necrosis) for distinguishing different forms of cell death. Preliminary data have reported altered levels of cytokeratin 18 fragments in patients with acute coronary syndrome (ACS) and ischemic heart disease. In this study, serum levels of M30 and M65 were measured in 74 patients with ACS [including 17 cases with unstable angina and 57 patients with acute myocardial infarction (AMI)], 25 patients with stable angina, and 23 controls.

METHODS

In patients with ACS, serial measurements of M30 and M65 were obtained, and for each patient, the following values were determined: (i) values at admission, (ii) values obtained 24 h after symptom onset, and (iii) values obtained at 48 h after symptom onset. The severity of coronary atherosclerosis was expressed using the Gensini score.

RESULTS

On admission, M30 and M65 levels in ACS patients were similar to those observed in stable angina patients and control participants. In AMI patients, serum levels of M30 peaked at 24 h and declined thereafter at 48 h. Notably, serum levels of M30 measured at 24 h correlated significantly and positively with the extent of coronary artery disease as measured by the Gensini score in AMI patients (r = 0.253, P<0.05).

CONCLUSION

Serum levels of the apoptotic marker M30 peak at 24 h after AMI and reflects the extent of coronary artery disease in this patient group.

Myocardial lipofuscin-laden lysosomes contain the apoptosis marker caspase-cleaved cytokeratin-18

BACKGROUND

Acute coronary syndrome is related to increased circulatory concentration of soluble apoptosis specific caspase-cleaved cytokeratin-18 (ccCK-18). Potential cardiac sources of this intermediate filament derivative have not been investigated to date.

MATERIALS AND METHODS

Paraffin embedded tissue of normal myocardium, and chronically damaged samples of ischaemic, congestive and hypertrophic cardiomyopathy were analysed by histology and by CK-8, CK-18, ccCK-18 immunohistochemistry (each group, n = 15). Antibody specificity of the ccCK-18 antibody M30 was checked by immunoblotting on lysed myocardium and enriched myocardial lysosomes.

RESULTS

ccCK-18 and CK-18 but not CK-8 were present in all forms of cardiomyopathy, most prominently in ischaemic cardiomyopathy while only traces were detectable immunohistochemically in normal myocardium. Weak CK-18 and strong ccCK-18 staining co-localized to lysosomes with cardiac age pigment lipofuscin. Weak staining of CK-18 was detected in the cytoplasm of coronary endothelia.

CONCLUSION

Our study reveals that cardiac lipofuscin-laden lysosomes contain ccCK-18, a marker of apoptosis and its precursor CK-18. This ccCK-18 pool might contribute to increased systemic levels of ccCK-18 in acute coronary syndrome thus monitoring myocardial damage.

Elevated levels of interleukin-1beta-converting enzyme and caspase-cleaved cytokeratin-18 in acute myocardial infarction

BACKGROUND

Systemic inflammation and apoptosis-specific immune activation play a major role in acute coronary syndromes (ACS) including acute myocardial infarction (AMI). The role of systemic and coronary obtained inflammatory plasma protein interleukin-1beta precursor (IL-1betap), IL-1beta-converting enzyme (ICE) and the apoptosis-specific caspase-cleaved cytokeratin-18 (ccCK-18) are not known in ACS.

MATERIALS AND METHODS

Plasma samples were obtained from stable angina (SA, n = 34), unstable angina (UA, n = 37) and patients with AMI (n = 39). Coronary blood was acquired by means of thrombectomy devices (X-sizer) in AMI patients. IL-1betap, ICE and ccCK-18 were determined by enzyme-linked immunosorbent assay (ELISA). Group comparisons were evaluated by parametric Tukey test. Multivariate logistic regression analysis was performed to determine predictive values of IL-1betap, ICE and ccCK-18 as compared to creatine kinase (CK) and troponin T (TnT) in order to relate these markers with the occurrence of myocardial damage.

RESULTS

IL-1betap, ICE and ccCK-18 were identified to be significantly altered in the peripheral blood of patients suffering from AMI as compared to SA and UA. ROC curves were plotted and revealed that ccCK-18 is a novel sensitive marker for the detection of myocardial damage as compared to TnT or CK. (AUC ccCK-18 0.925, TnT AUC 0.62 and CK AUC 0.858.) Moreover, ICE and ccCK-18 were significantly increased at the site of coronary occlusion as compared to peripheral blood samples in AMI patients (both P < 0.001).

CONCLUSION

Our data suggest that ACS is related to increased concentration of systemic soluble ICE and ccCK-18. Moreover, soluble ccCK-18 was identified to be a superior marker as compared to TnT or CK, for detection of myocardial damage.

Autoantibodies from synovial lesions in chronic, antibiotic treatment-resistant Lyme arthritis bind cytokeratin-10

Although the causative agent of Lyme disease is definitively known to be the tick-borne spirochete, Borrelia burgdorferi, the etiology of chronic joint inflammation that ensues in a subset of patients remains less well understood. Persistence of arthritis after apparent eradication of the spirochete suggests an autoimmune reaction downstream of the original bacterial infection. We have generated recombinant Ab probes from synovial lesions within affected arthritic joints in an attempt to recapitulate disease-relevant Ag-binding specificities at the site of injury. Using this panel of intra-articular probes, as well as Ab fragments derived from patient peripheral blood, we have identified cytokeratin 10, present in synovial microvascular endothelium, as a target ligand and a putative autoantigen in chronic, antibiotic treatment-resistant Lyme arthritis. Furthermore, there is cross-reactivity between cytokeratin 10 and a prominent B. burgdorferi Ag, outer surface protein A. Release of the self protein in the context of inflammation-induced tissue injury and the resulting in situ response to it could set in motion a feed-forward loop, which amplifies the inflammatory process, thereby rendering it chronic and self-perpetuating, even in the absence of the inciting pathogen.