Caitlin M. Tressler

Age‐related changes in large‐vessel biomechanics may contribute to neurovascular dysfunction and region‐specific biochemical remodeling in the brain, with important implications for female health. This study investigated the impact of aging on neck vasculature and brain lipid biochemistry in female C57BL/6NHsd mice by comparing young (12 weeks; n = 10) and middle‐aged (52 weeks; n = 10) cohorts using ultrasound imaging, histology, and mass spectrometry. In vivo ultrasound quantified carotid and jugular hemodynamics, including wall shear stress (WSS), circumferential cyclic strain (CCS), pulsatility index, and volumetric flow. Ex vivo assessments included spatial lipid mapping in vessels and brain, and histology staining to quantify elastin‐to‐collagen ratios. Middle‐aged females exhibited reduced carotid systolic velocity, systolic WSS, and body weight–normalized carotid volumetric flow compared to young controls, while pulsatility index and CCS showed non‐significant decreases. Histology revealed a reduction in the carotid elastin‐to‐collagen ratio, consistent with vascular remodeling. Lipidomic profiling identified age‐dependent shifts in lipid headgroups, including decreases across multiple brain lipid classes, increased N‐acylethanolamides, alongside increases in carotid cardiolipin and lysophosphatidylethanolamine. Hippocampal spectra showed clearer age‐related separation than whole‐brain analyses. Correlation analyses identified moderate to strong associations between vascular biomechanics and lipid features across tissues, supporting coordinated neurovascular and biochemical aging in female mice.

Supplementary Tables S1–S4: Patient demographics and tissue pathology (Table S1); ROC AUC results for metabolite/lipid comparisons across Normal, IPMN, and PDAC tissues (Table S2); MS/MS dot-product spectral matching scores (Table S3); diagnostic MS/MS fragments, m/z, mass errors, and compound assignments (Tables S4a–S4b).

MS/MS spectra and fragmentation pattern of metabolites and lipids identified in pancreatic tissue samples.

Bar plots depicting the relative abundance of significantly dysregulated m/z features in normal/non-neoplastic pancreas tissue, IPMN, and PDAC tissue samples.

Purpose:Metabolic reprogramming plays an integral role in progression, immune evasion, and response to treatment in many cancers, including pancreatic ductal adenocarcinoma (PDAC). This study aimed to spatially characterize the metabolic and lipidomic alterations in PDAC and its precursor lesion, intraductal papillary mucinous neoplasm (IPMN), compared with normal/nonneoplastic pancreatic tissue. Experimental Design:Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was employed to perform spatial metabolic and lipidomic profiling of human PDAC, IPMN, and normal/nonneoplastic pancreatic tissues. MALDI-MSI provided multiplexed metabolic images of tissue samples at 200 μm resolution, allowing spatial characterization of the tumor metabolic landscape. Results:Our data identified metabolic signatures characteristic of PDAC, with several of these altered in IPMN compared with normal/nonneoplastic tissue. The metabolic fingerprint of PDAC was characterized by increased levels of taurine, ascorbic acid, and a variety of lipid species, including most of the phosphatidylcholines (PC) and sphingomyelins compared with normal/nonneoplastic pancreas tissue, alongside elevated acetylcarnitine, butyrylcarnitine, and PC (PC 34:3) relative to IPMN; significant reductions were observed in creatine, malate, and lysophosphatidylcholine (LPC 16:0). In contrast, IPMN tissues demonstrated a significant reduction of xanthine, arginine, and tryptophan compared with normal/nonneoplastic pancreas tissue. These metabolic signatures were spatially heterogeneous. Conclusions:Our findings provide novel insights into the metabolic and lipidomic underpinnings of PDAC. Metabolic alterations in PDAC were associated with proliferation, immune evasion, and treatment resistance.

MALDI-MSI analysis showing the spatial distribution of dysregulated m/z features in pancreatic tissue samples. The ion images display metabolite localization patterns in normal/non-neoplastic pancreas tissue, IPMN, and PDAC tissue samples.

Fold SLC6A6 mRNA expression in normal/non-neoplastic pancreas tissue (blue dots, n = 4), IPMN (green dots, n = 3) and PDAC samples (red dots, n = 3). Values represent the mean ± SEM. Statistical significance is denoted by an asterisk (*), indicating p-values less than 0.05; # represents p-value = 0.067.

Histogram plots showing spatial homogeneity in normal/non-neoplastic pancreas tissue, IPMN, and PDAC tissue samples.

A correlation heatmap with hierarchical clustering displaying pairwise Spearman rank correlation coefficients between tissue samples based on metabolite expression profiles.

Hematoxylin and eosin-stained images of normal/non-neoplastic pancreatic tissue samples.