Hironori Izutani

Background: Calcific aortic valve disease (CAVD) is characterized by progressive inflammatory and fibrocalcific remodeling. Although valvular interstitial cells (VICs) are generally considered to drive fibrosis and osteogenic remodeling, whether injury-activated VICs mount endogenous protective responses that preserve the valvular interstitial microenvironment and restrain calcification remains unknown. Methods: We performed spatial transcriptomic profiling of aortic valves in a mouse model of endothelial injury-induced CAVD to define early injury-responsive programs within the valvular interstitium. The cellular origin and spatial distribution of candidate protective factors were examined by immunohistochemistry and lineage tracing, and their relevance to human disease was assessed using stenotic aortic valves. The functional role of CTHRC1 was investigated using genetic Cthrc1 deficiency combined with longitudinal hemodynamic assessment, histological analysis, and spatial transcriptomic profiling. Results: Spatial transcriptomics identified Cthrc1 as a prominent component of an early injury-induced stromal response in the expanding valvular interstitium. CTHRC1 was strongly expressed in activated VICs within thickened murine valve leaflets and human stenotic aortic valves. Lineage tracing demonstrated that the expanded VIC population arose predominantly from PDGFRβ ⁺ resident interstitial cells, with minimal endothelial contribution. Despite comparable early hemodynamic responses to endothelial injury, Cthrc1 deficiency exacerbated chronic valvular calcification. Spatial profiling of Cthrc1 -deficient valves revealed pronounced interstitial accumulation of galectin-3 ⁺ foamy macrophages, accompanied by mitochondrial respiratory-chain signature loss and cell death-associated pathway activation. These findings indicate that transient CTHRC1 induction after endothelial injury defines an endogenous stromal protective response that preserves the valvular interstitial microenvironment and limits macrophage-associated tissue injury and subsequent dystrophic calcification. Conclusions: Injury-activated VICs are not merely effectors of pathological remodeling, but can engage an endogenous tissue-protective response through CTHRC1. These findings identify a previously unrecognized stromal defense mechanism linking endothelial injury to macrophage-associated inflammatory remodeling and dystrophic calcification and suggest CTHRC1-dependent stromal protection as a potential therapeutic axis for limiting CAVD progression.

Background: Secondary aorto-oesophageal fistula (AEF) after aortic aneurysm repair is a rare but clinically catastrophic complication. Conservative management is associated with an unacceptably high risk of mortality, primarily due to severe infections. Although definitive in situ aortic reconstruction may be curative, it is highly invasive and carries substantial peri-operative morbidity and mortality, particularly in frail patients or those with established infection. This case report describes the successful treatment of a secondary AEF without aortic arch reconstruction, achieving durable long-term infection control. Case summary: A 74-year-old man was referred to our hospital with haematemesis, and a pseudoaneurysm was identified at the distal anastomosis site following total aortic arch replacement. Emergency thoracic endovascular aortic repair (TEVAR) was performed as a life-saving measure to achieve rapid haemostasis and stabilization. One month later, persistent fever and a residual oesophageal perforation prompted oesophagectomy with omental flap placement, without aortic arch reconstruction. Gastric conduit reconstruction was performed 4 months after TEVAR. The patient has remained event-free for more than 1 year after the initial presentation and intervention. Discussion: This case highlights the importance of an individualized treatment strategy for secondary AEF. In selected patients, infection control may be achieved without aortic arch reconstruction.

Background: Surgical treatment such as grafting or thoracic endovascular aortic repair (TEVAR) is recommended for Stanford type B acute aortic dissection (SB-AAD) with complications. We report a case of SB-AAD with acute renal failure caused by malperfusion that was successfully treated with TEVAR. Case summary: A 69-year-old man was diagnosed with SB-AAD at another hospital. Because he experienced worsening renal function, the patient was referred to our hospital. Enhanced computed tomographic angiography (CTA) revealed an entry point at the distal aortic arch and re-dissection that extended to the level of the bilateral iliac arteries. The entry site was approximately 20 mm distal to the origin of the subclavian artery on the greater curvature side. Because this false lumen compressed both renal arteries, we suspected renal ischaemia as the cause of acute renal failure and oliguria. We performed urgent TEVAR with left subclavian artery occlusion to improve renal ischaemia and function. Thereafter, urine output increased and renal function improved. Follow-up CTA performed 1 week postoperatively showed no enlargement of the dissection cavity or leakage. Favourable vascular remodelling was observed during 5-year follow-up. Discussion: Thoracic endovascular aortic repair performed in the early phase of SB-AAD may result in a satisfactory clinical course and vascular remodelling. However, careful consideration of its timing is required.

The precise molecular pathways driving fibrosis and calcification in aortic valve leaflets remain poorly defined. Here, we present the first data indicating a role for caldesmon-1 (CALD1) in calcified aortic valve disease (CAVD) pathogenesis. Analysis of publicly available single-cell RNA sequencing (scRNA-seq) datasets revealed that CALD1 shows prominent upregulation in aortic valve stenosis (AS) cases when compared to normal subjects. Histological examination demonstrated that CALD1 protein expression is elevated in calcified AS valves and co-localises with α-smooth muscle actin (a myofibroblast biomarker) and vimentin, indicating its association with activated valvular interstitial cells (VICs). Bioinformatic analysis showed that CALD1-positive cells predominantly synthesize extracellular matrix components, including COL1A1 . Functional experiments using CALD1-depleted VICs revealed that CALD1 is required for maintaining spindle-shaped morphology, actin polymerisation, and proliferative capacity. Moreover, CALD1 loss significantly impaired osteoblast differentiation and attenuated VIC calcification. Bulk RNA-seq combined with pathway analysis demonstrated that CALD1-mediated actin polymerisation positively regulates key osteogenic and valvulopathy-related genes, including RUNX2 and ALPL . Collectively, these findings identify CALD1 as a novel regulator of VIC phenotypic plasticity and osteogenic transition during CAVD progression, providing mechanistic insight and a target for potential AS therapy.

Introduction and importance: Elderly and frail patients with thoracic aortic aneurysms (TAAs) near to origins of cervical arteries present facing challenges with aortic arch replacement with cardiopulmonary bypass, and traditional tube-type stent-grafts are also inadequate for transcatheter endovascular aortic repair (TEVAR). Thus, necessitating precise treatment with fenestrated stent-grafts from zone 0. This approach is crucial for achieving favorable postoperative outcomes without compromising activities of daily living (ADL). Case presentations: An 85-year-old-man admitted to the hospital for treatment of a large TAA. While arch replacement is a definitive procedure, it is highly invasive, and the postoperative ADL are expected to be significantly lower than preoperative levels. Therefore, we performed a debranching TEVAR from Zone 0 with fenestrated stent-graft. The patient was discharged from the hospital on the 11th postoperative day. Clinical discussion: In frail and elderly patients for whom conventional surgery may not be viable, TEVAR emerges as a preferred alternative. However, TEVAR of TAA proximal to the aortic arch continues to pose challenges, necessitating meticulous attention to the cervical branches in the intervention strategy. While surgical intervention in these patients necessitates careful consideration of its suitability, including the potential for postoperative enhancement in ADL, the use of fenestrated stent-grafts from Zone 0 emerges as one of the treatment modalities. Conclusion: The authors present a very elderly case in which fenestrated stent-grafts were used to avoid aortic arch replacement for a large aortic arch aneurysm, resulting in a good postoperative course with no decline in ADL.

A 27-year-old male was admitted to our hospital due to lymphocytic fulminant myocarditis. He required ECPELLA (V-A ECMO+Impella) management for 10 days. His cardiac function did not improve, and needed an external ventricular-assisted device (VAD) for 5 months. The severity of aortic insufficiency was moderate (Figure 1A), and he underwent aortic valve replacement during an implantable VAD (HeartMate 3^TM) implantation. The aortic valve leaflets obtained at the surgery were pathologically evaluated. All leaflets showed thickening (Figure 1B). Haematoxylin and eosin staining revealed penetration of erythrocytes into the stroma in all leaflets (Figure 1C). Macrophages surrounded the deformed erythrocytes (Figure 1E). In addition, von Kossa staining showed scattered microcalcifications (Figure 1D and F). In experiments on mice, guidewire injury to the aortic valve causes infiltration of macrophages into the damaged valve leaflets and are associated with calcification.^1,2 In the context of the present case, it is suggested that the aortic valve was injured by IMPELLA insertion, red blood cells attached and invaded, and calcification might be induced by macrophages that phagocytosed them.

Objectives: The molecular mechanisms underlying post-operative pericardial adhesions remain poorly understood. We aimed to unveil the temporal molecular and cellular mechanisms underlying tissue dynamics during adhesion formation, including inflammation, angiogenesis, and fibrosis.Methods and Results: We visualized cell-based tissue dynamics during pericardial adhesion using histological evaluations. To determine the molecular mechanism, RNA-seq was performed. Chemical inhibitors were administered to confirm the molecular mechanism underlying adhesion formation. A high degree of adhesion formation was observed during the stages in which collagen production was promoted. Histological analyses showed that arterioles excessively sprouted from pericardial tissues after the accumulation of neutrophils on the heart surface in mice as well as humans. The combination of RNA-seq and histological analyses revealed that hyperproliferative endothelial and smooth muscle cells with dedifferentiation appeared in cytokine-exposed sprouting vessels and adhesion tissue but not in quiescent vessels in the heart. SMAD2/3 and ERK activation was observed in sprouting vessels. The simultaneous abrogation of PI3K/ERK or TGF-β/MMP9 signaling significantly decreased angiogenic sprouting, followed by inhibition of adhesion formation. Depleting MMP9-positive neutrophils shortened mice survival and decreased angiogenic sprouting and fibrosis in the adhesion. Our data suggest that TGF-β/matrix metalloproteinase-dependent tissue remodeling and PI3K/ERK signaling activation might contribute to unique angiogenesis with dedifferentiation of vascular smooth muscle cells from the contractile to the synthetic phenotype for fibrosis in the pericardial cavity.Conclusions: Our findings provide new insights in developing prevention strategies for pericardial adhesions by targeting the recruitment of vascular cells from heart tissues.

The characterization of aortic valve interstitial cells (VICs) cultured under optimal conditions is essential for understanding the molecular mechanisms underlying aortic valve stenosis. Here, we propose 2% hypoxia as an optimum VIC culture condition. Leaflets harvested from patients with aortic valve regurgitation were digested using collagenase and VICs were cultured under the 2% hypoxic condition. A significant increase in VIC growth was observed in 2% hypoxia (hypo-VICs), compared to normoxia (normo-VICs). RNA-sequencing revealed that downregulation of oxidative stress-marker genes (such as superoxide dismutase) and upregulation of cell cycle accelerators (such as cyclins) occurred in hypo-VICs. Accumulation of reactive oxygen species was observed in normo-VICs, indicating that low oxygen tension can avoid oxidative stress with cell-cycle arrest. Further mRNA quantifications revealed significant upregulation of several mesenchymal and hematopoietic progenitor markers, including CD34, in hypo-VICs. The stemness of hypo-VICs was confirmed using osteoblast differentiation assays, indicating that hypoxic culture is beneficial for maintaining growth and stemness, as well as for avoiding senescence via oxidative stress. The availability of hypoxic culture was also demonstrated in the molecular screening using proteomics. Therefore, hypoxic culture can be helpful for the identification of therapeutic targets and the evaluation of VIC molecular functions in vitro.