Hisashi Sawada

Background: The Barthel Index (BI) is a reliable tool for assessing the level of independence in activities of daily living (ADLs). Current risk stratification for chronic limb-threatening ischemia (CLTI) primarily focuses on anatomical severity and comorbidities, with less emphasis on functional status. Although several studies have examined its prognostic utility in patients with CLTI, the association between BI at admission and wound healing outcomes remains unclear, particularly in the context of multidisciplinary treatment strategies. Methods: This retrospective single-center study included 187 patients (220 limbs) with CLTI and tissue loss who underwent endovascular treatment (EVT). Patients were stratified into 4 groups according to their BI at admission: total independence (TI, BI ≥ 85), partial independence (PI, BI: 61–84), partial assistance (PA, BI: 41-60), and total assistance (TA, BI: ≤ 40). The primary endpoint was wound healing rate, and secondary analyses examined major amputation and ADL recovery. Results: Baseline disease severity and treatment characteristics were comparable among the 4 groups. Most patients showed functional improvement during hospitalization, except those with high baseline BI who already maintained good independence. However, patients in the TA group exhibited significantly lower 1-year wound healing rates compared with PA, PI, and TI groups. Major amputations were also more frequent in the TA group. Multivariable Cox regression analysis identified BI ≤ 40 at admission as an independent negative predictor of wound healing, suggesting limited responsiveness to standardized multidisciplinary care, including EVT and rehabilitation, in these patients. Conclusions: A lower BI at admission was associated with delayed wound healing and a higher risk of major amputation despite appropriate EVT. These findings highlight the clinical value of incorporating functional assessment into current risk stratification frameworks. Barthel Index assessment at admission is a simple and reliable prognostic indicator for patients with CLTI and may aid in early risk stratification and optimization of treatment strategies, including the consideration of the intensity of revascularization and rehabilitation efforts. Clinical Impact: This study demonstrates that the Barthel Index, a simple and readily available measure of functional status, provides clinically meaningful prognostic information in patients with chronic limb-threatening ischemia beyond conventional assessments of disease severity. A low Barthel Index at admission identifies patients who remain at high risk for delayed wound healing and major amputation despite guideline-based multidisciplinary treatment, including endovascular revascularization. Incorporating the Barthel Index into the initial evaluation improves risk stratification, facilitates individualized treatment planning, optimizes rehabilitation and resource allocation, and supports shared decision-making.

BACKGROUND: Mice harboring a missense variant (C1041G) of Fbn1 have been used extensively for aortopathy research, but do not mimic all facets of the human disease. The role of increased AngII (angiotensin II) or blood pressure in determining the arterial phenotype of these mice remains incompletely defined. The purpose of this study was to determine whether AngII, either directly or indirectly through increased blood pressure, promotes pathology in the proximal thoracic aorta and beyond. METHODS: Fbn1 ^+/+ and Fbn1 ^C1041G/+ littermates were infused with either AngII or norepinephrine via subcutaneously implanted osmotic pumps. Microcomputed tomography was used to visualize vascular pathologies. Maximal arterial dimensions were measured using in situ or microcomputed tomography images. RESULTS: AngII infusion dramatically augmented aortopathy in Fbn1 ^C1041G/+ mice. Aortic dissection was visible within 3 days of AngII infusion. Over 50% of male Fbn1 ^C1041G/+ mice died during AngII infusion, primarily due to aortic rupture in either the thoracic or abdominal regions. Surviving males had increased ascending and suprarenal aortic diameters and developed pathological lesions at the celiac and superior mesenteric branches of the abdominal aorta. Female mice had a much lower incidence of death but had increased ascending aortic and branch diameters. Although norepinephrine infusion also increased systolic blood pressure, it did not affect mortality or enlarge aortic or branch diameters in Fbn1 ^C1041G/+ mice. While microcomputed tomography identified novel pathological changes during AngII infusion, including the development of aortic branch aneurysms in the celiac and superior mesenteric arteries, the maximal diameters of the adjacent suprarenal aorta showed only modest increases in male Fbn1 ^C1041G/+ mice. CONCLUSIONS: AngII exacerbated aortic pathology in Fbn1 ^C1041G/+ mice. It also promoted the development of pathologies at aortic branch points, including the celiac and superior mesenteric arteries.

Following aortic dissection (AD), there is a sustained risk of vascular complications, progressive false lumen aneurysm formation, and rupture. However, no effective therapy exists to prevent these complications, highlighting the need to elucidate the pathophysiology following AD. Elastic fibers are crucial for maintaining aortic wall integrity but are thought to have limited regenerative capacity once disrupted during AD. This study defined that elastic fibers were newly generated in the false lumen wall following AD in humans and mice. In human ADs, new elastic fibers were observed in the false lumen wall 6 months after onset. In mice with descending AD induced by β-aminopropionitrile (BAPN), elastin mRNA was markedly upregulated in the chronic phase following AD, accompanied by elastic fiber formation. These fibers coincided with smooth muscle cell (SMC) markers within the false lumen wall. Of note, lineage tracing studies demonstrated that these cells were not derived from resident SMCs but adventitial progenitor cells. In vitro experiments further demonstrated that adventitial progenitor cells produced elastic fibers while expressing SMC markers. Collectively, these findings suggest that adventitial progenitor cells differentiate into elastogenic SMC-like cells, contributing to false lumen remodeling through de novo elastic fiber formation following AD.

Angiotensin II (AngII) exerts a critical role in thoracic aortic aneurysm (TAA) formation via AngII type 1a receptor (AT1aR). However, the principal cell type mediating this process remains unclear. Our previous study demonstrated that S100A4-lineage cells are present in the aortic wall and involved in AngII-induced vascular remodeling. In the present study, we investigated whether S100A4-lineage cells contribute to AngII-mediated TAA formation through AT1aR. Proteomic, bulk RNA sequencing, and single-cell RNA sequencing data were analyzed to assess changes in S100A4 abundance in response to AngII infusion. Lineage tracing was performed to track S100A4-lineage cells during AngII-mediated TAA formation. Either saline or AngII was infused in mice with genetic deletion of AT1aR in S100A4-lineage cells and their wild-type littermates. AngII infusion increased S100A4 protein and mRNA abundance significantly in the ascending aorta, particularly within smooth muscle cells and fibroblasts. Lineage tracing revealed that S100A4-positive cells were localized to the media and adventitia under basal conditions. Following AngII infusion, S100A4-lineage cells expanded markedly throughout the entire aortic wall and comprised a heterogeneous population including smooth muscle cells and fibroblasts. Deletion of AT1aR in S100A4-lineage cells partially reduced AngII-induced TAA formation. In conclusion, S100A4-lineage cells modestly contribute to AngII-mediated TAA development through AT1aR in mice.

Background: Mice harboring a missense variant (C1041G) of fibrillin-1 ( Fbn1 ) have been used extensively for aortopathy research, but do not mimic all facets of the human disease. The role of increased angiotensin II (AngII) or blood pressure in determining the arterial phenotype of these mice remains incompletely defined. The purpose of this study was to determine whether AngII, either directly or indirectly through increased blood pressure, promotes pathology in the proximal thoracic aorta and beyond. Methods: Fbn1 ^+/+ and Fbn1 ^C1041G/+ littermates were infused with either AngII or norepinephrine (NE) via subcutaneously implanted osmotic pumps. Micro computed tomography (microCT) was used to visualize vascular pathologies. Maximal arterial dimensions were measured using in situ or microCT images. Results: AngII infusion dramatically augmented aortopathy in Fbn1 ^C1041G/+ mice. Aortic dissection was visible within 3 days of AngII infusion. Over 50% of male Fbn1 ^C1041G/+ mice died during AngII infusion, primarily due to aortic rupture in either the thoracic or abdominal regions. Surviving males had increased ascending and suprarenal aortic diameters and developed pathological lesions at the celiac and superior mesenteric branches of the abdominal aorta. Female mice had a much lower incidence of death but had increased ascending aortic and branch diameters. Although NE infusion also increased systolic blood pressure, it did not affect mortality or enlarge aortic or branch diameters in Fbn1 ^C1041G/+ mice. MicroCT identified novel pathological changes during AngII infusion, including development of aortic branch aneurysms in the celiac and superior mesenteric arteries; however, the maximal diameters of the adjacent suprarenal aorta showed only modest increases in male Fbn1 ^C1041G/+ mice. Conclusion: AngII exacerbated aortic pathology in Fbn1 ^C1041G/+ mice. It also promoted development of pathologies at aortic branch points, including the celiac and superior mesenteric arteries.

Aims: Plasminogen activator inhibitor-1 (PAI-1) regulates plasmin-mediated proteolysis, thereby influencing vascular stability and tissue remodeling. Angiotensin II (AngII) induces an increase in PAI-1 during the development of ascending thoracic aortic aneurysm (ATAA). The initial purpose of this study was to determine whether deletion of PAI-1 influenced development of ATAA. Subsequently, this study aimed to define the early pathological events preceding cardiac fibrosis in PAI-1 deficiency and the structural domain responsible for its protective effect. Methods and results: AngII was infused for 4 weeks in whole-body PAI-1 deficient (PAI-1−/−) mice and their wild-type littermates (PAI-1+/+) to examine the role of PAI-1 in ATAA. PAI-1 deficiency did not alter AngII-induced aortopathy but revealed a striking cardiac phenotype characterized by replacement fibrosis predominantly within the epicardium and posterior septum. Ferric iron, indicative of prior hemorrhage, was coincident with fibrosis. Similar phenotypes were observed in PAI-1−/− mice infused with norepinephrine for 4 weeks. To define the pathological events preceding cardiac fibrosis, either AngII or norepinephrine was infused for 1 week in PAI-1+/+ or −/− mice. Both infusions induced extensive epicardial hemorrhage and posterior septal fibrosis in PAI-1−/− mice. To explore the initiation of cardiac pathology, AngII was infused for approximately 1 day. PAI-1−/− mice developed diffuse hemorrhage and cardiomyocyte injury localized to the posterior septum, pathologic changes that preceded overt fibrosis. Finally, to determine the protective domain of PAI-1, saline or AngII was administered to mice harboring loss-of-function point mutations in the protease inhibitory (PAI-1 ^Ala/Ala ) or somatomedin B-binding domains (PAI-1 ^AK/AK ). Compared to saline infusion, 1 week of AngII induced hemorrhage and heterogeneous fibrosis in PAI-1 ^Ala/Ala , but not PAI-1 ^AK/AK mice. Conclusions: These findings support that, under hemodynamic stress, PAI-1 deficiency promotes early cardiac hemorrhage and cardiomyocyte injury that lead to fibrosis. Mutational studies implicate dysregulated plasmin generation as an initiator of cardiac injury and fibrosis. TRANSLATIONAL PERSPECTIVE: Cardiac fibrosis has been reported in a human population with PAI-1 deficiency and currently lacks targeted therapy. Our findings demonstrate that in animal models, PAI-1 deficiency confers susceptibility to cardiac injury in response to hemodynamic stress, which may accelerate fibrotic remodeling. Mutational disruption of the protease-inhibitory domain of PAI-1 induced similar pathology, supporting a protective role for this function. These observations suggest that interventions aimed at controlling hypertension, promoting endothelial integrity, or regulating plasmin activation could reduce fibrotic remodeling in this population.

Thoracic aortopathies are life-threatening diseases including aneurysm, dissection, and rupture. Cilostazol, a phosphodiesterase (PDE) 3 inhibitor, and sildenafil, a PDE5 inhibitor, have been used clinically for peripheral arterial disease and erectile dysfunction or pulmonary hypertension, respectively. Recent studies report their effects on abdominal aortic aneurysm formation. However, their impacts on thoracic aortopathy remain unknown. In this study, we investigated whether cilostazol and sildenafil affect thoracic aortopathy induced by β-aminopropionitrile (BAPN) administration in mice. Bulk RNA sequencing analysis revealed that BAPN administration upregulated Pde3a transcription in the ascending aorta and Pde5a in both ascending and descending regions before thoracic aortopathy formation. Next, we tested the effects of cilostazol or sildenafil on BAPN-induced thoracic aortopathy. BAPN-administered mice were fed a diet supplemented with either cilostazol or sildenafil. Mass spectrometry measurements determined the presence of cilostazol or sildenafil in the plasma of mice fed drug-supplemented diets. However, neither drug altered BAPN-induced aortic rupture nor aneurysm formation and progression. These results provide evidence that cilostazol and sildenafil did not influence BAPN-induced thoracic aortopathy in mice.

Background: Metformin, a biguanide antihyperglycemic agent, prevents angiotensin II (AngII)-induced abdominal aortic aneurysm formation in apolipoprotein E-deficient (ApoE−/−) mice. Low-density lipoprotein receptor-deficient (LDLR−/−) mice are also widely used as a hypercholesterolemic model, which more closely mimics the lipoprotein profile of patients with hypercholesterolemia than ApoE−/− mice. In addition, LDLR−/− mice exhibit characteristics of glucose metabolism that are distinct from ApoE−/− mice. However, it remains unknown whether metformin suppresses AngII-induced aortic aneurysm formation in LDLR−/− mice. Methods: Male LDLR−/− mice at 9 weeks of age were administered either vehicle or metformin in drinking water and fed a Western diet. Subsequently, AngII was infused into mice for 4 weeks. Plasma metformin concentrations were measured by mass spectrometry. Maximal aortic diameters and areas were measured ex vivo. Results: Mass spectrometry analysis determined plasma metformin concentrations in mice administered the drug. Metformin administration resulted in lower body weight compared to the vehicle group, indicating effective metformin administration. However, ex vivo measurements demonstrated that metformin did not reduce aortic diameters in the suprarenal abdominal region. In addition, metformin failed to prevent AngII-induced ascending aortic dilatations. Conclusion: Metformin did not attenuate AngII-induced aortic aneurysm formation in either the ascending or suprarenal abdominal region of LDLR−/− mice.