Effect of estrogen receptor α on cardiopulmonary adaptation to chronic developmental hypoxia in a rat model

Humans living at high-altitude (HA) have adapted to this environment by increasing pulmonary vascular and alveolar growth. RNA sequencing data from a novel murine model that mimics this phenotypical response to HA suggested estrogen signaling via estrogen receptor alpha (ERα) may be involved in this adaptation. We hypothesized ERα was a key mediator in the cardiopulmonary adaptation to chronic hypoxia and sought to delineate the mechanistic role ERα contributes to this process by exposing novel loss-of-function ERα mutant (ERαMut) rats to simulated HA. ERα mutant or wild-type (wt) rats were exposed to normoxia or hypoxia starting at conception and continued postnatally until 6 wk of age. Both wt and ERαMut animals born and raised in hypoxia exhibited lower body mass and higher hematocrits, total alveolar volumes (Va), diffusion capacities of carbon monoxide (DLCO), pulmonary arteriole (PA) wall thickness, and Fulton indices than normoxia animals. Right ventricle adaptation was maintained in the setting of hypoxia. Although no major physiologic differences were seen between wt and ERαMut animals at either exposure, ERαMut animals exhibited smaller mean linear intercepts (MLI) and increased PA total and lumen areas. Hypoxia exposure or ERα loss-of-function did not affect lung mRNA abundance of vascular endothelial growth factor, angiopoietin 2, or apelin. Sexual dimorphisms were noted in PA wall thickness and PA lumen area in ERαMut rats. In summary, in room air-exposed rats and rats with peri- and postnatal hypoxia exposure, ERα loss-of-function was associated with decreased alveolar size (primarily driven by hypoxic animals) and increased PA remodeling.NEW & NOTEWORTHY By exposing novel loss-of-function estrogen receptor alpha (Erα) mutant rats to a novel model of human high-altitude exposure, we demonstrate that ERα has subtle but inconsistent effects on endpoints relevant to cardiopulmonary adaptation to chronic hypoxia. Given that we observed some histologic, sex, and genotype differences, further research into cell-specific effects of ERα during hypoxia-induced cardiopulmonary adaptation is warranted.

Immunogenomics and spatial proteomic mapping highlight distinct neuro-immune architectures in melanoma vs. non-melanoma-derived brain metastasis

BACKGROUND

Brain metastases (BrMs) are a devastating complication of solid tumours. A better understanding of BrMs biology is needed to address their challenging clinical management.

METHODS

Immunogenomic and digital spatial analyses were applied to interrogate the peripheral blood and tumour specimens derived from 53 unique patients with BrMs originating from different solid tumours.

RESULTS

At craniotomy time, patients with melanoma-derived brain metastasis (MBM) displayed in the periphery lower neutrophil-lymphocyte ratio (NLR) compared to non-melanoma-derived brain metastasis (non-MBM). Regardless of the primary tumour source, higher NLR was associated with reduced overall survival (OS). Tumour MicroEnviroment genomic evaluations revealed higher expression of genes identifying NK, CD8 and B cells in MBM vs. non-MBM. Moreover, MBM patients with longer OS displayed increased CD8+ cell infiltration. Spatial proteomic analysis further highlighted enriched infiltration of CD8+ cells, antigen-presenting cells, T-cell agonists and B cells in MBM. Conversely, increased expression of genes and proteins associated with neurodevelopment, cell-cell adhesion and neutrophil infiltration were observed in non-MBM.

CONCLUSIONS

These findings reveal an increased immunogenicity of MBM vs non-MBM and highlight the presence of a unique neuro-immune interplays in MBM vs non-MBM, suggesting that a balance between neuro-immune architectures might be associated with diverging clinical outcome of patients with BrMs.

Surgical Management of Thick Primary Cutaneous Melanoma in the US

BACKGROUND

There remains significant variability in the surgical management of thick melanoma patients with clinically node-negative disease. We evaluated factors influencing overall survival (OS) in these patients, focusing on the surgical management of the primary tumor and nodal basin.

METHODS

Using the National Cancer Database, we identified 7647 patients diagnosed between 2012 and 2017 with thick melanoma (> 4 mm, T4) and clinically node-negative disease. 4332 patients had complete data and met all inclusion criteria. These patients were stratified into three groups based on nodal assessment: sentinel lymph node biopsy (SLNB), elective lymphadenectomy (ELND), or no nodal evaluation (NNE). OS was compared using Kaplan-Meier analyses and multivariable Cox proportional hazard regression.

RESULTS

In the cohort, 2851 (65.8%) had a SLNB, 799 (18.4%) had an ELND, and 682 (15.7%) had NNE. OS significantly decreased for each millimeter of increasing Breslow thickness. Ulceration, lymphovascular invasion, and tumor-positive SLN (+SLN) were associated with worse OS (all p < 0.001). The size of surgical margins was not significantly associated with OS. Five-year OS of patients with SLNB was 67.1% ± 1.2% compared to 57.9% ± 2.3% with ELND and 46.8% ± 2.5% with NNE (p < 0.001). Among +SLN patients, a complete lymph node dissection (CLND) was performed in 400 (62.3%) but was not associated with improved OS (p = 0.67) when compared to the nodal observation group.

CONCLUSION

Our results suggest that increasing Breslow thickness and nodal assessment provide important prognostic information regarding OS for thick melanoma patients, which emphasizes the importance of SLNB for staging and confirm the lack of benefit of CLND after +SLN in thick melanoma. The size of surgical margins did not affect OS.

Lung endothelial cell heterogeneity in health and pulmonary vascular disease

Lung endothelial cells (ECs) are essential for maintaining organ function and homeostasis. Despite sharing some common features with ECs from organ systems, lung ECs exhibit significant heterogeneity in morphology, function, and gene expression. This heterogeneity is increasingly recognized as a key contributor to the development of pulmonary diseases like pulmonary hypertension (PH). In this mini-review, we explore the evolving understanding of lung EC heterogeneity, particularly through the lens of single-cell RNA sequencing (scRNA-seq) technologies. These advances have provided unprecedented insights into the diverse EC subpopulations, their specific roles, and the disturbances in their homeostatic functions that contribute to PH pathogenesis. In particular, these studies identified novel and functionally distinct cell types such as aerocytes and general capillary ECs that are critical for maintaining lung function in health and disease. In addition, multiple novel pathways and mechanisms have been identified that contribute to aberrant pulmonary vascular remodeling in PH. Emerging techniques like single-nucleus RNA sequencing and spatial transcriptomics have further pushed the field forward by discovering novel disease mediators. As research continues to leverage these advanced techniques, the field is poised to uncover novel EC subtypes and disease mechanisms, paving the way for new therapeutic targets in PH and other lung diseases.