Early clinical presentation of diffuse, severe, multi-district atherosclerosis after radiation therapy for Hodgkin lymphoma

Ionizing radiation induces vascular smooth muscle cell senescence through activating NF-κB/CTCF/p16 pathway

Radiation injury of blood vessels (RIBV) is a serious long-term complication of radiotherapy, characterized by the development of atherosclerosis. The involvement of vascular smooth muscle cells (VSMCs) senescence in the pathogenesis of radiation-induced atherosclerosis has been implicated, yet the precise mechanisms governing VSMCs senescence remain inadequately comprehended. In this study, the senescence of VSMCs was examined by employing SA-β-gal staining and assessing the expression of p16 and p21, both in vivo and in vitro. Our findings revealed that ionizing radiation (IR) has the potential to augment cellular senescence. In addition, IR significantly activated the NF-κB pathway, as evidenced by increased p65 nuclear translocation, phospho-p65 expression, and enhanced binding ability of p65 (EMSA). Furthermore, a decrease in HMGB2 expression following exposure to IR was observed via Western blot analysis, while CTCF expression remained unchanged. Interestingly, the formation of CTCF spatial clustering was detected under super-resolution fluorescence microscopy. Concurrently, the ChIP technique identified the facilitation of the interaction between CTCF and p16 gene through IR. The inhibition of CTCF or the overexpression of HMGB2 through lentiviruses effectively eliminates the formation of CTCF clusters and the upregulation of p16 and p21 after IR. Inhibition of NF-κB activation induced by IR by PDTC (100 μM) led to a decrease in the staining of SA-β-gal, a reduction in p16 expression, an increase in HMGB2 protein expression and a decrease in CTCF clusters formation. This study provided significant insights into the role and mechanism of IR in VSMCs senescence by regulating NF-κB/CTCF/p16 pathway.

Radiation-Induced Vascular Disease-A State-of-the-Art Review

Since the 1990s, there has been a steady increase in the number of cancer survivors to an estimated 17 million in 2019 in the US alone. Radiation therapy today is applied to a variety of malignancies and over 50% of cancer patients. The effects of ionizing radiation on cardiac structure and function, so-called radiation-induced heart disease (RIHD), have been extensively studied. We review the available published data on the mechanisms and manifestations of RIHD, with a focus on vascular disease, as well as proposed strategies for its prevention, screening, diagnosis, and management.

Changes in the Common Carotid Artery after Radiotherapy: Wall Thickness, Calcification, and Atherosclerosis

BACKGROUND AND PURPOSE

Since the long-term survival rate has improved in laryngeal cancer patients who receive radiotherapy, concerns about postradiation complications (including carotid atherosclerosis) have increased. We followed changes in the common carotid artery (CCA) after radiotherapy and identified the underlying risk factors.

METHODS

Consecutive patients with laryngeal cancer who underwent radiotherapy between January 1999 and December 2009 and who had received computed tomography (CT) both pre- and postradiotherapy were enrolled. Changes in the wall thickness and in the vessel and lumen areas as well as the presence of calcification or atherosclerosis were investigated. Demographics and risk factors were compared between patients with and without atherosclerosis at follow-up CT.

RESULTS

In total, 125 patients were enrolled. The wall thickness had increased and the lumen area had decreased several months after radiotherapy. These changes were not associated with vascular risk factors and were not progressive. Calcification and atherosclerosis were observed in 37 (29.6%) and 71 (56.8%) patients, respectively. Diabetes was associated with calcification (p=0.02). The prevalence of hyperlipidemia was higher in patients with atherosclerosis (28.2% vs. 11.1%, p=0.02) and for a longer period postradiation [62.7±32.1 vs. 40.0±24.2 months (mean±SD), p<0.001]. Atherosclerosis occurred mostly in the middle portion of the CCA (n=31, 24.6%), followed by the proximal CCA at the intrathoracic level (n=26, 20.6%) and the distal CCA (n=6, 4.8%). Positive remodeling was also observed, but this was less common in patients with calcification (p=0.02).

CONCLUSIONS

Various types of postradiation changes occur in the CCA and can be easily observed in postradiation CT. The prevalence and burden of postradiation atherosclerosis increased in a close relationship with baseline cholesterol levels and the time after radiotherapy. Postradiation atherosclerosis was observed at unusual sites of the CCA.

[Radiation-induced carotid stenosis: A personnalized approach]

INTRODUCTION

Surgical treatment of radio-induced carotid stenosis (RICS) is challenging and burdened by an elevated risk of local complications. Carotid artery stenting (CAS) may be a suitable alternative. The best approach is yet to be defined. We reviewed the results of both techniques following selection based on better-suitability characteristics (anatomic and clinical).

METHODS

We retrospectively reviewed 38 patients treated for 43 RICS from a group of 1230 patients who had carotid interventions between 2008 and 2015 (5 bilateral). Primary endpoints were morbidity and mortality at 30 days (transient ischemic attack, stroke, myocardial infarction, or death). Secondary endpoints were technical success, wound complications, cranial nerve injury (CNI), restenosis (≥50%) and recurrent symptoms.

RESULTS

RICS was symptomatic in 6 patients in the OR group and 3 in the CAS group. Lesions in the OR group were longer (P=0.02) and more calcified (P=0.08). Technical success rate was 100%. Cranial nerve injury rate was 14.2% (3/21). All injuries were completely resolved within several weeks. In the CAS group, technical success rate was 95% (21/22) with the one failure due to a residual stenosis exceeding 30%. Periprocedural stroke rates were 0% and 4.5% in the OR and CAS groups respectively (0/21 vs 1/22, P=0.32). There were no early deaths. Mean follow-up was 19.1 months (3-75). The restenosis rate was 9.5% (2/21) in the OR group and 9% (2/22) in the CAS group.

CONCLUSION

Our results do not support a preferred treatment strategy. The choice of treatment should be considered on an individual basis.

Effects of neck radiation therapy on extra-cranial carotid arteries atherosclerosis disease prevalence: systematic review and a meta-analysis

Introduction

Radiation arteritis following neck irradiation as a treatment for head and neck malignancy has been well documented. The long-term sequelae of radiation exposure of the carotid arteries may take years to manifest clinically, and extra-cranial carotid artery (ECCA) stenosis is a well-recognised vascular complication. These carotid lesions should not be regarded as benign and should be treated in the same manner as standard carotid stenosis. Previous studies have noted increased cerebrovascular events such as stroke in this cohort of patients because of high-grade symptomatic carotid stenosis resulting in emboli.

Aim

To evaluate the effect of radiation therapy on ECCA atherosclerosis progression.

Methods

Online search for case-control studies and randomised clinical trials that reported on stenosis in extra-cranial carotid arteries in patients with neck malignancies who received radiation therapy (RT) comparing them to patients with neck malignancies who did not receive RT.

Results

Eight studies were included in the final analysis with total of 1070 patients – 596 received RT compared to 474 in the control group. There was statistically significant difference in overall stenosis rate (Pooled risk ratio  =  4.38 [2.98, 6.45], P  =  0.00001) and severe stenosis (Pooled risk ratio  =  7.51 [2.78, 20.32], P <0.0001), both being higher in the RT group. Pooled analysis of the five studies that reported on mild stenosis also showed significant difference (Pooled risk ratio  =  2.74 [1.75, 4.30], 95% CI, P  =  0.0001).

Conclusion

The incidence of severe ECCA stenosis is higher among patients who received RT for neck malignancies. Those patients should be closely monitored and screening programs should be considered in all patients who receive neck RT.