Targeting novel antigens in the arterial wall in thromboangiitis obliterans

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.

Case report: morphological aspects of Buerger's disease

Buerger's disease is a rather rare pathology characterized by nonatherogenic vascular lesion associated with the inflammation in the intima of the vessel and the thrombus formation. Most often the pathological process affects small and medium caliber arteries. Vascular occlusion can lead to tissue ischemia and the trophic ulcers, and cause the extremity amputation. The disorder pathogenesis has not been fully explored. Literature data indicate that the disease development may be associated with autoimmune processes. The paper presents the results of immunohistochemical study of the material obtained after amputation of the lower extremity in a patient diagnosed with Buerger's disease. The patient had a 15-year tobacco smoking experience. In the inflammatory cell infiltrates around the affected vessels, lymphocytes with CD4, CD8 antigens and IgG immunoglobulin deposits were found, which could be considered as the evidence of the autoimmune mechanisms’ involvment. Immunohistochemical reactions with markers of NK cells CD56 and the central component of the C3d complement system were negative. The results of the study suggest that the key role is played by helper and suppressor T lymphocytes, as well as by humoral antibodies of the IgG class.