The main etiology of constrictive pericarditis (CP) has changed from tuberculosis to therapeutic mediastinal radiation and cardiac surgery. Occult constrictive pericardial disease (OCPD) is a covert disease in which CP is manifested in a condition of volume overload. A 60-year-old patient with a history of thoracic radiation therapy for non-Hodgkin’s lymphoma (40 years earlier) was transferred to our hospital for treatment of repeated congestive heart failure. For a preoperative hemodynamic study, pre-hydration with intravenous normal saline (50 mL/hour) was used to manifest the pericardial disease and prevent contrast-induced nephropathy. The hemodynamic study showed a right ventricular dip-plateau pattern and discordance of right and left ventricular systolic pressures during inspiration, which was not seen in the volume-controlled state. These responses were concordant with OCPD. A pericardiectomy, aortic valve replacement, and mitral and tricuspid valve repair were performed. Postoperatively, the heart failure was controlled with standard medication. This case revealed a volume-induced change in hemodynamics in OCPD with severe combined valvular heart disease, which suggests the importance of considering OCPD in patients who had undergone radiation therapy 40 years before.

Pulmonary arterial hypertension (PAH) remains a disease with poor prognosis; thus, a new mechanism for PAH treatment is necessary. Circulating nerve growth factor receptor (Ngfr)-positive cells in peripheral blood mononuclear cells are associated with disease severity and the prognosis of PAH patients; however, the role of Ngfr in PAH is unknown. In this study, we evaluated the function of Ngfr using Ngfr gene-deletion (Ngfr^−/−) mice. To elucidate the role of Ngfr in pulmonary hypertension (PH), we used Ngfr^−/− mice that were exposed to chronic hypoxic conditions (10% O₂) for 3 weeks. The development of hypoxia-induced PH was accelerated in Ngfr^−/− mice compared to littermate controls. In contrast, the reconstitution of bone marrow (BM) in Ngfr^−/− mice transplanted with wild-type BM cells improved PH. Notably, the exacerbation of PH in Ngfr^−/− mice was accompanied by the upregulation of pulmonary vascular remodeling-related genes in lung tissue. In a hypoxia-induced PH model, Ngfr gene deletion resulted in PH exacerbation. This suggests that Ngfr may be a key molecule involved in the pathogenesis of PAH.

SUMMARY: Therapeutic angiogenesis using mesenchymal stem/stromal cell grafts have shown modest and controversial effects in preventing amputation for patients with critical limb ischemia. Through single-cell transcriptomic analysis of human tissues, we identified CD271 ⁺ progenitors specifically from subcutaneous adipose tissue (AT) as having the most prominent pro-angiogenic gene profile distinct from other stem cell populations. AT-CD271 ⁺ progenitors demonstrated robust in vivo angiogenic capacity, over conventional adipose stromal cell grafts, characterized by long-term engraftment, augmented tissue regeneration, and significant recovery of blood flow in a xenograft model of limb ischemia. Mechanistically, the angiogenic capacity of CD271 ⁺ progenitors is dependent on functional CD271 and mTOR signaling. Notably, the number and angiogenic capacity of CD271 ⁺ progenitors was strikingly reduced in insulin resistant donors. Our study highlights the identification of AT-CD271 ⁺ progenitors with in vivo superior efficacy for limb ischemia. Furthermore, we showcase comprehensive single-cell transcriptomics strategies for identification of suitable grafts for cell therapy. HIGHLIGHTS: Adipose tissue stromal cells have a distinct angiogenic gene profile among human cell sources. CD271 ⁺ progenitors in adipose tissue have a prominent angiogenic gene profile. CD271 ⁺ progenitors show superior therapeutic capacities for limb ischemia. CD271 ⁺ progenitors are reduced and functionally impaired in insulin resistant donors. GRAPHICAL

Our work elucidated the negative feedback between heart failure (HF) and the number and function of adipocyte progenitor cells (APCs). HF drastically decreases CD24⁺ APC number and proliferative capacity. Furthermore, we discovered that HF impaired the capacity of APCs to differentiate into mature adipocytes. In conclusion, impaired APC function in HF would be a new research target to ameliorate severe HF outcomes in patients with cachexia.

Therapeutic angiogenesis mediated by stem/progenitor cells is an attractive therapeutic option against cardiovascular disease (CVD). Adipose tissue (AT) can be safely obtained even in CVD patients with anti-platelet medications, and it is a readily available source of culture-expanded adipose-derived stem cells (ADSCs) for transplantation. Single-cell transcriptome enables us to screen all the surface markers at once, while conventional strategies have been limited for the number of target markers. Furthermore, gene profiling at single-cell resolution can be used for the quantification of each marker by how many favorable cells can be purified without mixing of detrimental cells. We aimed to identify and characterize a cell population with in vivo angiogenic potential by single-cell RNA sequencing (scRNA-seq) analysis and xenograft experiments. We revisited scRNA-seq datasets of single cell fraction from AT, bone-marrow (BM), and umbilical-cord blood (UCB, n=6/organ) to find cell populations with pro-angiogenic potential. Next, we collected AT from CVD patients (n=23) and used multicolor flow cytometry to quantify and sort the specific populations. PBS, the specific marker-negative and unsorted ADSCs were used as controls. Xenograft models of PKH26 pre-labeled human ADSC transplantation in limb ischemia were used to evaluate the lectin capillary density, PKH⁺ engrafted ADSCs, and blood flow recovery. Clustering divided CD45^–CD31^–CD34⁺ progenitor fraction into 3 clusters. We identified pro-/anti-angiogenic clusters based on the expressions of well-known pro-/anti-angiogenic factors. All genes encoding cell-surface proteins were compared in this functional clustering, resulted in 17 markers screened (Fig. 1A, B). Taken together with enrichment analysis, CD271⁺ cells showed predominant and pro-angiogenic gene profile from the other top candidates including CD36 and CD54 (Fig. 1C, D). Next, we evaluated the number and gene profile of CD271⁺ cells in well-known stem cell sources including BM and UCB. Surprisingly, the number of CD271 expressing cells were significantly lower and did not show angiogenic gene profile in BM and UCB (Fig. 2A). In analysis of AT from 23 CVD patients, CD271⁺ cells were significantly decreased by donor insulin resistance (Fig. 2B). Cell therapy using CD271⁺ ADSCs demonstrated in vivo angiogenic capacity compared to those of CD271^– ADSCs and PBS in limb ischemia model. Furthermore, CD271⁺ ADSC transplantation showed enhanced efficacy compared to unsorted ADSCs from the same donors (Fig. 2C–E). In this study, we identified CD271⁺ cell population in AT as an angiogenic cell population through scRNA-seq analysis and cell therapy experiments. AT obtained from donors without insulin resistance would be the most suitable for CD271⁺ ADSC isolation. CD271⁺ ADSC transplantation with a promising angiogenic capacity could contribute better cell-based therapy tackling CVD. Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science (JSPS) KAKENHI (Tokyo, Japan) Figure 1 Figure 2