Endocan: A Novel Marker of Endothelial Dysfunction in C1-Inhibitor-Deficient Hereditary Angioedema

Diagnostic Tools and Biomarkers for Severe Drug Eruptions

In accordance with the development of human technology, various medications have been speedily developed in the current decade. While they have beneficial impact on various diseases, these medications accidentally cause adverse reactions, especially drug eruption. This delayed hypersensitivity reaction in the skin sometimes causes a life-threatening adverse reaction, namely Stevens-Johnson syndrome and toxic epidermal necrolysis. Therefore, how to identify these clinical courses in early time points is a critical issue. To improve this problem, various biomarkers have been found for these severe cutaneous adverse reactions through recent research. Granulysin, Fas ligands, perforin, and granzyme B are recognized as useful biomarkers to evaluate the early onset of Stevens-Johnson syndrome and toxic epidermal necrolysis, and other biomarkers, such as miRNAs, high mobility group box 1 protein (HMGB1), and S100A2, which are also helpful to identify the severe cutaneous adverse reactions. Because these tools have been currently well developed, updates of the knowledge in this field are necessary for clinicians. In this review, we focused on the detailed biomarkers and diagnostic tools for drug eruption and we also discussed the actual usefulness of these biomarkers in the clinical aspects based on the pathogenesis of drug eruption.

Roles of Immune Cells in Hereditary Angioedema

Hereditary angioedema (HAE) is a rare genetic disease, characterized by recurrent and unexpected potentially life-threatening mucosal swelling. HAE may be further classified into HAE with C1‐inhibitor deficiency (C1‐INH‐HAE) and HAE with normal C1‐INH activity (nlC1‐INH‐HAE), mostly due to mutations leading to increased vascular permeability. Recent evidence implicates also the innate and adaptive immune responses in several aspects of angioedema pathophysiology. Monocytes/macrophages, granulocytes, lymphocytes, and mast cells contribute directly or indirectly to the pathophysiology of angioedema. Immune cells are a source of vasoactive mediators, including bradykinin, histamine, complement components, or vasoactive mediators, whose concentrations or activities are altered in both attacks and remissions of HAE. In turn, through the expression of various receptors, these cells are also activated by a plethora of molecules. Thereby, activated immune cells are the source of molecules in the context of HAE, and on the other hand, increased levels of certain mediators can, in turn, activate immune cells through the engagement of specific surface receptors and contribute to vascular endothelial processes that lead to hyperpemeability and tissue edema. In this review, we summarize recent developments in the putative involvement of the innate and adaptive immune system of angioedema.

Impaired endothelial function irrespective of systemic inflammation or atherosclerosis in mastocytosis

BACKGROUND

Knowledge on endothelial dysfunction and its relation to atherosclerosis in mastocytosis is limited.

OBJECTIVE

To investigate the endothelial function in mastocytosis by flow-mediated dilatation (FMD) and biomarkers related to vascular endothelia and to evaluate its relationship with the presence of subclinical atherosclerosis by carotid intima media thickness (CIMT).

METHODS

A total of 49 patients with mastocytosis and 25 healthy controls (HCs) were included. The FMD and CIMT during transthoracic echocardiography biomarkers including endocan, endothelin-1, and vascular endothelial growth factor (VEGF) were measured in the sera of participants. Tumor necrosis factor-alpha, interleukin 6, and high-sensitive C-reactive protein were determined as inflammatory biomarkers.

RESULTS

The mean FMD % was lower in the patients than HCs (11.26% ± 5.85% vs 17.84% ± 5.27% P < .001) and was the lowest in the advanced systemic mastocytosis and smoldering systemic mastocytosis group among the patients (P = .03). The median value of VEGF was considerably higher in patients than HCs (73.30 pg/mL; minimum-maximum 32.46-295.29 pg/mL vs 46.64 pg/mL; minimum-maximum, 11.09-99.86 pg/mL; P = .001) and it was the highest in the advanced systemic mastocytosis and smoldering systemic mastocytosis group (P = .01). The FMD was inversely correlated with endocan (r = -0.390; P = .006), endothelin-1 (r = -0.363; P = .01) and VEGF (r = -0.402; P = .004) but there were no correlations between FMD and tumor necrosis factor-alpha, interleukin 6, and high-sensitive C-reactive protein. No differences in CIMT values between patients and HCs and no correlation between CIMT and the biomarkers were observed.

CONCLUSION

Endothelial dysfunction in mastocytosis becomes evident with decreased FMD and elevated serum VEGF in the absence of atherosclerosis or systemic inflammation and is related to disease severity.

Biomarkers in Hereditary Angioedema

A biomarker is a defined characteristic measured as an indicator of normal, biologic, pathogenic processes, or biological responses to an exposure or intervention. Diagnostic biomarkers are used to detect a disease or a subtype of a disease; monitoring biomarkers are measured serially to assess a medical condition; response biomarkers are used to check biologic response following a medical intervention; predictive biomarkers are used to identify patients who are more likely to respond to a medical intervention; and prognostic biomarkers are used to assess the future likelihood of a clinical event. Although biomarkers have been extensively investigated and validated in many diseases and pathologies, very few are currently useful for the diagnosis, evaluation of disease activity, and treatment of hereditary angioedema (HAE). Pathophysiologic pathways involved in HAE reveal a plethora of molecules from the complement, coagulation, and fibrinolysis systems or from the vascular endothelium, which may serve as biomarkers. The most promising candidates, together with their laboratory readout systems, should be evaluated with regard to their analytical and clinical validity and utility. To be highly specific, such biomarkers should be linked to the pathomechanisms of HAE, particularly the bradykinin-generating cascade. Additionally, major advances in high-throughput omics-based technologies may facilitate the discovery of new candidate biomarkers in the future. This review will cover the existing as well as future potential biomarkers that will support the diagnosis, monitor disease activity, and can be used to assess the efficacy of new avenues of therapy of HAE and other forms of angioedema.

The central role of endothelium in hereditary angioedema due to C1 inhibitor deficiency

An impairment of the endothelial barrier function underlies a wide spectrum of pathological conditions. Hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) can be considered the "pathophysiological and clinical paradigm" of Paroxysmal Permeability Diseases (PPDs), conditions characterized by recurrent transient primitively functional alteration of the endothelial sieving properties, not due to inflammatory-ischemic-degenerative injury and completely reversible after the acute flare. It is a rare yet probably still underdiagnosed disease which presents with localized, non-pitting swelling of the skin and submucosal tissues of the upper respiratory and gastrointestinal tracts, without significant wheals or pruritus. The present review addresses the pathophysiology of C1-INH-HAE with a focus on the crucial role of the endothelium during contact and kallikrein/kinin system (CAS and KKS) activation, currently available and emerging biomarkers, methods applied to get new insights into the mechanisms underlying the disease (2D, 3D and in vivo systems), new promising investigation techniques (autonomic nervous system analysis, capillaroscopy, flow-mediated dilation method, non-invasive finger plethysmography). Hints are given to the binding of C1-INH to endothelial cells. Finally, crucial issues as the local vs systemic nature of CAS/KKS activation, the episodic nature of attacks vs constant C1-INH deficiency, pros and cons as well as future perspectives of available methodologies are briefly discussed.

Recent Advances in Clinical Allergy and Immunology 2019

The immune system has vital functions for homeostasis and host defense. Thus, imbalances of the immune system whether associated with allergy, hypersensitivity, or autoimmunity are of great importance, as is manifest from common diseases such as atopic diseases, urticaria, and angioedema, and drug hypersensitivity reactions. These can affect patients' quality of life and can generate high costs for health care. Epidemiological studies have provided evidence for changing patterns of allergic diseases caused by lifestyle and climate changes which have consequences for medical care. Deeper insights into the pathogenesis of allergic/immunologic diseases, combined with novel technologies, provide improved diagnostic options and treatment measures. This review will summarize novel aspects of the epidemiology, pathogenic mechanisms, as well as disease management in the fields of allergy and clinical immunology.

The Relationship Between Serum Endocan Level and Aortic Elastic Properties in Patients With Newly Diagnosed Essential Hypertension

Endothelial dysfunction plays role in the generation of both essential hypertension (EH) and aortic stiffness. We evaluated the relationship between serum endocan level and aortic elastic properties (AEPs) assessed with the aortic strain, aortic distensibility, and aortic stiffness index by echocardiography. Newly diagnosed EH patients (n = 67) and controls (n = 70) were included in the study. The EH group was subdivided into stage 1 and 2 EH groups. A higher endocan level was found in the EH group, compared to the controls (34.2 ± 13.0 vs 24.1 ± 7.3 ng/mL, respectively, P < .001). All the AEP parameters were worse in the EH group, compared to the controls. Further, endocan levels correlated with aortic distensibility ( r = −0.305, P < .001) and aortic strain ( r = −0.181, P = .038), but not with aortic stiffness index ( r = 0.162, P = .064) in the whole study population. Aortic elastic properties deteriorate and serum endocan level increases in patients with EH. Moreover, serum endocan level shows a correlation with deteriorated AEPs, and hence may a surrogate marker of escalating aortic stiffness in patients with newly diagnosed EH.

Recent Advances in Clinical Allergy and Immunology

Allergic diseases are of great concern because of their high prevalence, which is still rising in several regions, their impact on patients' physical and psychological health, the huge burden they place on patients' quality of life, as well as the socioeconomic consequences that they cause. Recent research has provided new data on both genetic and environmental risk factors of atopic/allergic diseases. The application of new technologies such as "omics" has allowed a better understanding of the pathogenesis and has helped with the identification of therapeutic targets. Immense progress has been made in developing and applying novel, targeted therapies, for example for asthma and urticaria. Intensive efforts are being made to find biomarkers that help to classify patients, to identify their potential responsiveness to specific therapies, and to monitor the disease severity. Based on recent insights in the pathogenesis of food allergy and drug hypersensitivity, novel strategies for diagnostics, allergen avoidance, and induction of tolerance have been developed. Here, we summarize important findings in the field of clinical allergy and immunology with a special focus on asthma, allergic rhinitis, atopic dermatitis, food allergy, urticaria, angioedema, and drug hypersensitivity.