Inflammatory Thoracic Aortic Aneurysm in a Patient with Advanced Lung Adenocarcinoma Treated with Pembrolizumab

[Aortitis]

Aortitis is a rare disease entity of unknown prevalence. Primary aortitis mainly affects the thoracic aorta. They are most often diagnosed on imaging by grade III 18-FDG uptake of the aortic wall on PET, or by circumferential thickening>2.2mm on CT or MRI with late-stage contrast. More rarely, aortitis is histologically proven, as in some cases of clinically isolated aortitis discovered after planned aortic aneurysm surgery or during aortic dissection surgery. The most common histological types are granulomatous/giant cell or lymphoplasmacytic. Clinical signs associated with aortitis are often non-specific: asthenia, fever, dry cough, chest, back, lumbar or abdominal pain. Aortitis can be divided into different etiological categories: primary aortitis, which includes vasculitis with a preferential or exclusive tropism for the aortic wall, aortitis secondary to systemic or iatrogenic diseases, and infectious aortitis. The main etiologies of primary aortitis are giant cell arteritis (GCA), Takayasu arteritis (TA) or clinically isolated aortitis. Aortitis secondary to systemic diseases is seen in atrophying polychondritis, systemic lupus and inflammatory rheumatic diseases such as spondyloarthropathy and rheumatoid arthritis. In both ACG and AT, aortitis is a negative factor, characterized by a higher risk of relapse, cardiovascular complications and increased mortality. The management of aortitis is insufficiently codified, and relies on the control of cardiovascular risk factors, with particular monitoring of blood pressure and LDL cholesterol, and on corticosteroid therapy and immunosuppressive drugs, the use of which will depend on the disease associated with the aortitis, the initial severity and comorbidities.

Unleashing PD-1: a duel of immunity in aortic aneurysm formation

Aortic aneurysms, particularly abdominal aortic aneurysms (AAAs), exhibit sex differences, with higher prevalence and severity in males than females, both in humans and experimental mouse models. In fact, male sex has been considered as the most potent nonmodifiable risk factor for AAA. Currently, there are no medications approved for the treatment of aortic aneurysms, despite the high lethality of ruptured aneurysms, which account for nearly 2% of all deaths. Moreover, the underlying molecular mechanisms mediating the sexual dimorphism of aortic aneurysms remain largely unknown. In this issue of the JCI, Mu et al. revealed a mechanism by which androgens, male sex hormones, exacerbate aortic aneurysms by suppressing programmed cell death protein 1 (PD-1) expression in T cells in an aldosterone and high salt-induced aortic aneurysm mouse model.

Androgen aggravates aortic aneurysms via suppression of PD-1 in mice

Androgen has long been recognized for its pivotal role in the sexual dimorphism of cardiovascular diseases, including aortic aneurysms (AAs), a devastating vascular disease with a higher prevalence and fatality rate in men than in women. However, the mechanism by which androgen mediates AAs is largely unknown. Here, we found that male, not female, mice developed AAs when exposed to aldosterone and high salt (Aldo-salt). We revealed that androgen and androgen receptors (ARs) were crucial for this sexually dimorphic response to Aldo-salt. We identified programmed cell death protein 1 (PD-1), an immune checkpoint, as a key link between androgen and AAs. Furthermore, we demonstrated that administration of anti-PD-1 Ab and adoptive PD-1-deficient T cell transfer reinstated Aldo-salt-induced AAs in orchiectomized mice and that genetic deletion of PD-1 exacerbated AAs induced by a high-fat diet and angiotensin II (Ang II) in nonorchiectomized mice. Mechanistically, we discovered that the AR bound to the PD-1 promoter to suppress the expression of PD-1 in the spleen. Thus, our study unveils a mechanism by which androgen aggravates AAs by suppressing PD-1 expression in T cells. Moreover, our study suggests that some patients with cancer might benefit from screenings for AAs during immune checkpoint therapy.

Aortic rupture following acute aortitis in a patient with head and neck carcinoma treated with nivolumab: a rare but severe immune-related adverse event

INTRODUCTION

Immune-related adverse events (irAEs) due to immune checkpoint inhibitors may lead to discontinuation and treatment-related death. Acute aortitis is a rare but severe irAE.

CASE PRESENTATION

A 67-year-old man with recurrent lower gingival carcinoma received nivolumab therapy. Twenty-three months later, he experienced chest compression, which resulted in syncope. Following a whole-body computed tomography (CT) scanning, which revealed diffuse thickening of the aorta, and systemic assessments of the causes of aortitis, he was diagnosed with acute aortitis due to irAE. Nivolumab discontinuation and oral steroids improved CT findings. However, 11 months after nivolumab discontinuation, he developed an aortic aneurysmal rupture. Endovascular aortic repair rescued him. A durable anti-cancer response was still observed 4 months after the aortic rupture.

CONCLUSION

Although severe irAE, such as acute aortitis, occurred, the patient may still achieve a durable response. A broad examination and prompt treatment of irAE can help improve the patient's survival.

Large-vessel vasculitis induced by pegfilgrastim and immune checkpoint inhibitor in a patient with small-cell lung cancer

A 75-year-old woman with stage IVB (cT3N3M1c) extensive disease small-cell lung cancer was treated with carboplatin, etoposide, and atezolizumab. Ten days after pegfilgrastim initiation, during the second chemotherapy cycle, she experienced back pain. Contrast-enhanced computed tomography revealed soft tissue thickening around the descending aorta and brachiocephalic artery. She was diagnosed with atezolizumab and pegfilgrastim-induced large-vessel vasculitis (LVV) and was treated with prednisolone, which was tapered and discontinued after 14 weeks, with no symptom recurrence. LVV should be included in the differential diagnosis of patients with nonspecific body pain when pegfilgrastim and immune checkpoint inhibitors are used in combination.

Androgen aggravates aortic aneurysms via suppressing PD-1 in mice

Androgen has long been recognized for its pivotal role in the sexual dimorphism of cardiovascular diseases, including aortic aneurysms, a devastating vascular disease with a higher prevalence and mortality rate in men than women. However, the molecular mechanism by which androgen mediates aortic aneurysms is largely unknown. Here, we report that male but not female mice develop aortic aneurysms in response to aldosterone and high salt (Aldo-salt). We demonstrate that both androgen and androgen receptors (AR) are crucial for the sexually dimorphic response to Aldo-salt. We identify T cells expressing programmed cell death protein 1 (PD-1), an immune checkpoint molecule important in immunity and cancer immunotherapy, as a key link between androgen and aortic aneurysms. We show that intraperitoneal injection of anti-PD-1 antibody reinstates Aldo-salt-induced aortic aneurysms in orchiectomized mice. Mechanistically, we demonstrate that AR binds to the PD-1 promoter to suppress its expression in the spleen. Hence, our study reveals an important but unexplored mechanism by which androgen contributes to aortic aneurysms by suppressing PD-1 expression in T cells. Our study also suggests that cancer patients predisposed to the risk factors of aortic aneurysms may be advised to screen for aortic aneurysms during immune checkpoint therapy.