Recent advances of oxidative stress in thromboangiitis obliterans: biomolecular mechanisms, biomarkers, sources and clinical applications

Oxidative stress (OS) has been identified as a key factor in the development of Thromboangiitis Obliterans (TAO). The detection of OS levels in clinical and scientific research practice is mainly based on the measurement of oxidative stress such as reactive oxygen species (ROS), reactive nitrogen species (RNS) and lipid peroxides. These markers are typically assessed through a combination of physical and chemical methods. Smoking is known to the state of OS in TAO, and OS levels are significantly increased in smokers due to inadequate antioxidant protection, which leads to the expression of apoptotic proteins and subsequent cell injury, thrombosis and limb ischemia. There, understanding the role of OS in the pathogenesis of TAO may provide insights into the etiology of TAO and a basis for its prevention and treatment.

Risk Factors, Mechanisms and Treatments of Thromboangiitis Obliterans: An Overview of Recent Research

BACKGROUND

Thromboangiitis obliterans (TAO) is a nonatherosclerotic thromboticocclusive vasculitis that affects the vessels of the small and medium-sized extremities. No explicit etiology or pathogenesis of TAO has been proven, and more effective treatments are needed.

OBJECTIVE

The study aimed to summarize and present an overview of recent advances regarding the risk factors, mechanisms and treatments of TAO and to organize the related information in figures to provide a comparatively complete reference.

METHODS

We searched PubMed for English-language literature about TAO without article type limits, including articles about the risk factors, pathological mechanisms and treatments of TAO in the last 10 years with essential supplements (references over ranges and English abstracts of Russian literature).

RESULTS

After screening content of works of literature, 99 references were evaluated. We found that risk factors of TAO include smoking, gene factors and periodontal diseases. The underlying mechanism of TAO involves oxidative stress, immunity, hemodynamic changes, inflammation and so on. Moreover, similarities in genetic factors and cigarette relevance existed between periodontal diseases and TAO, so further study of relationship was required. For TAO treatment, medicine, endovascular intervention and revascularization surgery, autologous cell therapy and novel therapies were also mentioned. Besides, a hypothesis that infection triggers autoimmunity in TAO could be speculated, in which TLR4 plays a key role.

CONCLUSION

1. A hypothesis is put forward that infections can trigger autoimmunity in TAO development, in which TLR4, as a key agent, can activate immune signaling pathways and induce autoimmune cytokines expression. 2. It is suggested to reconsider the association between periodontal diseases and TAO, as they share the same high-risk population. Controlling periodontal disease severity in TAO studies may provide new clues. 3. For TAO treatment, endovascular intervention and autologous cell therapy both showed promising long-term therapeutic effectiveness, in which autologous cell therapy is becoming more popular, although more clinical comparisons are needed.

The Imbalance among Oxidative Biomarkers and Antioxidant Defense Systems in Thromboangiitis Obliterans (Winiwarter-Buerger Disease)

(1) Background: Thromboangiitis obliterans or Winiwarter-Buerger disease (WBD), is an inflammatory, thrombotic occlusive, peripheral vascular disease, usually occurring in young smokers. The pathophysiological mechanisms underlying the disease are not clearly understood. The aim of this study is to investigate the imbalance between oxidants and antioxidants occurring in these patients. (2) Patients and Methods: In this cross-sectional study, 22 male patients with WBD and 20 healthy male smoking habit matched control group were included. To evaluate the possible sources of oxidative stress, the antioxidant biomarkers, and the markers of lipid peroxidation and protein oxidation, serum samples were analyzed for total oxidative status (TOS), total antioxidant capacity (TAC), myeloperoxidase (MPO), coenzyme Q10 (CoQ10), superoxide dismutase (SOD), glutathione reductase (GR), malondialdehyde (MDA), and protein carbonyl (PC) activity and/or content. (3) Results: The circulating levels of TOS, TAC, and CoQ10 were significantly higher in WBD patients, with respect to healthy smokers as controls. No significant difference was found among the serum level of PC, total cholesterol, MPO, and GR activity in WBD patients and healthy smoker controls. The activity of SOD and the mean serum level of MDA were significantly lower in WBD patients, with respect to healthy smoker controls. (4) Conclusion: Considerably high levels of oxidative stress were detected in WBD patients, which were greater than the antioxidant capacity. The low level of MDA may be associated with the enzymatic degradation of lipid peroxidation products. High levels of CoQ10 and low levels of SOD may be related to a harmful oxidative cooperation, leading to the vasoconstriction of WBD, representing a promising tool to discern possible different clinical risks of this poorly understood peripheral occlusive disease.

Molecular mechanisms regulating immune responses in thromboangiitis obliterans: A comprehensive review

Thromboangiitis obliterans (TAO) is a thrombotic-occlusive as well as an inflammatory peripheral vascular disease with unknown etiology. Recent evidence has supported the immunopathogenesis of the disease, however, the factors contributing to the altered immune function and vascular tissue inflammation are still unclear. This review was intended to collate the more current knowledge on the regulatory molecules involved in TAO from an immunoreactive perspective. The homeostasis of the immune system as well as a variety of progenitor cell populations appear to be affected during TAO and these alterations are associated with intrinsic signaling defects that are directing to an improved understanding of the crosstalk between angiogenesis and the immune system, as well as the potential of new co-targeting strategies applying both immunotherapy and angiogenic therapy.

Evaluation of HTLV-1 HBZ and proviral load, together with host IFN λ3, in pathogenesis of HAM/TSP

Human T-cell lymphotropic virus 1 (HTLV-1) is associated with two progressive diseases: HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia/lymphoma (ATLL). Although HTLV-1 proviral load (PVL) has been introduced as a risk factor for these diseases' progression, it is not sufficient on its own to yield an accurate estimation of the outcome of the infection. In the present study, PVL and HTLV-1 basic leucine zipper factor (HBZ) expression level as viral factors, and IFN λ3 as a host factor, were evaluated in HAM/TSP patients and HTLV-1 asymptomatic carriers (ACs). During 2014-2015, 12 HAM/TSP patients and 18 ACs who had been referred to the HTLV-1 Clinic, Ghaem Hospital, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran, were enrolled in this study. Peripheral blood mononuclear cells (PBMCs) were isolated and the DNA and mRNA were extracted for quantification of HBZ, IFN λ3 expression, and PVL using real-time PCR (TaqMan method). Although the PVL was higher in the HAM/TSP group, with a 94% confidence interval, there were no considerable differences in terms of HBZ mRNA and PVL between ACs and HAM patients. IFN λ3 expression in the HAM/TSP group was significantly higher than in the ACs (P = 0.02). To the best of our knowledge, no study has evaluated the expression level of IFN λ3 in HTLV-1 positive patients. The immune response against HTLV-1 viral antigens and virulent factors will therefore further refine our knowledge of interactions between the virus and host in the pathogenesis of HTLV-1-related disorders. The virus PVL and the host IFN λ3 can be used as pathogenic factors of HTLV-1 infected patients at risk of HAM/TSP manifestation. J. Med. Virol. 89:1102-1107, 2017. © 2016 Wiley Periodicals, Inc.

Evaluation of INOS, ICAM-1, and VCAM-1 gene expression: A study of adult T cell leukemia malignancy associated with HTLV-1

The main aim of this study was to evaluate the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and inducible nitric oxide synthase (iNOS) as host factors, and proviral load as the viral parameter, in adult T-cell leukemia/lymphoma (ATLL) individuals and healthy carrier (HC(s)) groups. Peripheral blood mononuclear cells (PBMC) from ATLL patients (n = 17) and HC subjects (as the control group, n = 17) were evaluated using real-time PCR to determine the levels of HTLV-1 proviral load and mRNA expression of ICAM, VCAM-1, and iNOS. ICAM-1 was significantly lower in ATLL patients than in control subjects. Although the expression of VCAM-1 was higher in ATLL individuals, there was no significant difference between the studied groups. In addition, no iNOS expression was found in ATLL patients, when compared to the HCs subjects, while ATLL patients demonstrated a higher level of proviral load when compared to the control group. Considering the importance of ICAM-1 in facilitating immune recognition of infected cells, it is posited that reduction of ICAM-1 expression is a unique strategy for circumventing appropriate immune responses that are mediated by different accessory proteins. Additionally, as the viral regulatory protein Tax and the NF-κB pathway play pivotal roles in expression of iNOS, lack of the latter in ATLL patients may be related to the level of Tax expression, disruption of the NF-κB pathway, or the occurrence of epigenetical mechanisms in the human iNOS promoter. Further studies are recommended to gain a better understanding of the interaction between host and viral factors in HTLV-1 pathogenesis and to identify a possible therapeutic target for ATLL.

Buerger's disease: providing integrated care

Buerger’s disease, also known as thromboangiitis obliterans (TAO), is a segmental inflammatory disease affecting small- and medium-sized vessels, which is strongly associated with tobacco use. Although the etiology is still unknown, recent studies suggest an immunopathogenesis. Diagnosis is based on clinical and angiomorphologic criteria, including age, history of smoking, clinical presentation with distal extremity ischemia, and the absence of other risk factors for atherosclerosis, autoimmune disease, hypercoagulable states, or embolic disease. Until now, no causative therapy exists for TAO. The most important therapeutic intervention is smoking cessations and intravenous prostanoid infusions (iloprost). Furthermore, effective analgesia is crucial for the treatment of ischemic and neuropathic pain and might be expanded by spinal cord stimulation. Revascularization procedures do not play a major role in the treatment of TAO due to the distal localization of arterial occlusion. More recently, immunoadsorption has been introduced eliminating vasoconstrictive G-protein-coupled receptor and other autoantibodies. Cell-based therapies and treatment with bosentan were also advocated. Finally, a consequent prevention and treatment of wounds and infections are essential for the prevention of amputations. To achieve better clinical results, integrated care in multidisciplinary and trans-sectoral teams with emphasis on smoking cessation, pain control, wound management, and social care by professionals, social workers, and family members is necessary.