- Letter to the Editor
- Open Access
Angiogenesis induction in Buerger's disease: a disease management double-edged sword?
Orphanet Journal of Rare Diseases volume 14, Article number: 189 (2019)
Due to unknown aetiology of Thromboangiitis obliterans (TAO), its effectively treating is challenging. However, angiogenesis induction is one of the acceptable treatments for TAO patients. Recently, we have noticed that TAO patients who were under long-term treatment with angiogenesis-inducing medication showed considerable improvement in terms of healing chronic ulcers over the course of one to 2 years of treatment. However, some of them developed dermal gangrene despite the warming of their feet, with or without palpable pulses in the extremities, and with hair growth on the affected skin. Unfortunately, following the progression of dermal gangrene, some of these patients had to undergo amputation and limb loss.
During histopathological evaluation, we detected some changes in the amputee TAO patients under long-term angiogenic medical treatment that were not present in amputee TAO patients who had not received any treatment for many years. The greatest pathological changes were observed in the microvascular of the skin, appearing as a proliferation of endothelial cells, NETosis and thrombus formation inside the vessels with proliferation of endothelial cells. The immunohistochemistry for CD31 and Ki67 as markers of vascular endothelium differentiation and cell mitosis confirmed the proliferation of endothelial cells. However, in the patients who had not received any treatment for years the typical pathology view of BD, including preserved vascular architecture with infiltration of inflammatory cells and inflammatory cells inside the thrombus, organised thrombus with recanalisation and intimal thickening was observed. Further longitudinal cohort studies regarding long-term treatment with angiogenic medications for TAO in different geographic areas are highly recommended.
Until recently, Thromboangiitis obliterans (TAO) has been regarded as a type of peripheral vascular disease usually involving small and medium-sized arteries . Due to its unknown aetiology, effectively treating TAO is challenging. However, angiogenesis induction is one of the suggestive treatments for TAO for patients with and without critical limb ischemia (CLI). Notably, most of the acceptable medical treatments for TAO that seek to achieve vasodilation can also induce angiogenesis.
For instance, iloprost upregulates the influence of vascular endothelium growth factor (VEGF) on endothelial cell proliferation and angiogenesis . Also, prostaglandin E1 analogues have been reported to induce neovascularisation in ischemic areas mainly by upregulating endothelial nitric oxide synthase (eNOS), hepatocyte growth factor (HGF) and VEGF . Notably, bosentan also induces upregulation of VEGF and eNOS levels in ischemic limbs and induces angiogenesis . Similarly, cilostazol induces angiogenesis and endothelial cell proliferation in ischemic limbs by upregulating HGF and VEGF .
Recently, we noted that TAO patients undergoing long-term treatment with angiogenesis-inducing medication, particularly cilostazol, showed considerable improvement in terms of reduced pain and claudication and healing of chronic ulcers over the course of 1 year of treatmesnt.
However, some of them developed dermal gangrene despite the warming of their feet with hair growth on the affected skin and improvement in pain and ulcer healing (Fig. 1). Unfortunately, following the progression of dermal gangrene, some of these patients had to undergo amputation and limb loss.
During histopathological evaluation, we detected some changes in the amputee TAO patients under long-term angiogenic medical treatment that were not present in amputee TAO patients who had not received any treatment for many years.
We studied 68 slides from 29 paraffin blocks of biopsies from two below-knee amputees and two toe amputee patients who were undergoing long-term treatment with antigenic medication. In addition, we evaluated 41 slides from 20 paraffin blocks of biopsies from five below-knee amputees with CLI who underwent amputation without receiving any medical treatment due to the progression of gangrene.
Notably, the gangrene of the extremities was limited to the derma in TAO patients with long-term angiogenic medical treatment, and granulation tissue generation and angiogenesis or a reduction of thrombus formation were observed in the small or medium-sized vessels. However, the greatest pathological changes were observed in the microvascular of the skin, appearing as a proliferation of endothelial cells. NETosis and thrombus formation were also observed inside the vessels with proliferation of endothelial cells (Fig. 2). Immunohistochemistry (IHC) was also performed for cluster of differentiation 31 (CD31) as a marker of vascular endothelium differentiation  and antigen Ki67 as a marker of cell mitosis and apoptosis inhibition . According to the results of IHC, extensive proliferation of endothelial cells in the soft tissue and proliferation of endothelial cells in the intima layer of microvessels were observed (Fig. 2).
However, in the patients who had not received any medical treatment before amputation the typical pathology view of TAO, including preserved vascular architecture with infiltration of inflammatory cells and inflammatory cells inside the thrombus, organised thrombus with recanalisation and intimal thickening was observed. However, proliferation of endothelial cells was not observed, as confirmed by IHC of CD31 and Ki67 (Fig. 3).
It appears that angiogenesis induction in TAO patients through long-term medical treatment, become dysregulated and induced obstruction instead of neo-vascularisation. We noted dermal gangrene primarily in the patients who had been taking cilostazol continually for more than six months. Dermal gangrene can be caused by the angiogenic induction that occurs in long-term use of cilostazol. Notably, Isner et al. also observed that induction of angiogenesis by phVEGF165 gene transfer in TAO patients led to forefoot gangrene in 33% of patients; they ultimately required below-knee amputation, despite evidence of improved perfusion .
Whilst the trigger for dysregulated angiogenesis is unknown, long-term treatment with angiogenic medication may be a risk factor for dermal gangrene in TAO patients and ultimately might be a disease management double-edged sword.
All in all, we suggest that TAO patients who receive long-term treatment with angiogenic medication be monitored carefully. Indeed, it might be the better course of action to pause the treatment to observe whether there is any evidence of gangrene. Moreover, a combination of angiogenic and anti-angiogenic medications that can also improve tissue oxygenises, such as pentoxifylline or antioxidants , may regulate angiogenesis in TAO and influence the disease outcomes of patients.
The limitation of our study is its small sample size. However, since our findings may influence the limb survival of TAO patients, further longitudinal cohort studies relative to long-term treatment with angiogenic medications in different geographic areas are highly recommended.
Availability of data and materials
All the pathology slides and blocks in addition to all the pictures from slides of TAO patients are available.
endothelial nitric oxide synthase
- H & E:
Haemotoxylin and eosin
Hepatocyte growth factor
Neutrophil extracellular traps
Vascular endothelium growth factors
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The authors would like to appreciate Mr.Reza Feyzi for his helpful cooperation in preparing the pictures from pathology slides.
All the authors declare that there is not any conflict of interest in preparing this letter.
Authors have received no funds for preparing this letter.
Ethics approval and consent to participate
This letter is not prepared from a research project. The data in this letter are gathered according to reporting and follow ups of TAO patients to our private office.
Consent for publication
The patients signed informed consent forms to permit inclusion of pictures of their feet in this letter (Ethical code: MUMS-941028).
There is no competing interests in preparing this letter.
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