Background: A hallmark of subclinical atherosclerosis is the accumulation of vascular smooth muscle cell (SMC)-like cells leading to intimal thickening, lipid retention and plaque formation, yet their origin remains controversial. The ability to discriminate heterogeneous populations of cells in the context of various disease processes is of potential clinical and diagnostic value.
Methods:The feasibility of multivariate analysis of single cell photonics as a discriminator of cell phenotype was assessed using label-free optical multi-parameter interrogation of single cells on a novel Lab-on-a-Disk (LoaD) platform before myogenic differentiation of a series of multipotent stem cells in vitro, and the cellular heterogeneity within vascular lesions in vivo, was determined using supervised machine learning and validated by genetic lineage tracing in vivo.Findings: Single cell photonics were of sufficient coverage, specificity, and quality to discriminate various disparate cell phenotypes in vitro and normal medial SMCs from SMClike cells following injury ex vivo, in addition to distinguishing myogenic differentiation of a series of multipotent stem cells in vitro. Supervised machine learning of these photonic datasets supported genetic lineage tracing analysis and identified the presence of S100β + stem-derived myogenic progeny within vascular lesions, in part, due to upregulation of Coll 3A1 and elastin.Interpretation: Disease-relevant photonic signatures reflect cell type and differentiation state and may have important predictive value as a phenotypic discriminator for vascular disease.
Research in contextEvidence before this study: Cardiovascular disease (CVD), the leading cause of death and disability world-wide is characterized by pathological structural changes to the blood vessel wall. Pathologic observations in humans vessels confirm that early 'transitional' lesions enriched with SMC-like cells are routinely present in atherosclerotic-prone regions of arteries during pathologic intimal thickening, prior to lipid retention, and the appearance of a atherosclerotic plaque. Lineage tracing and single cell RNA sequence analysis (scRNA-seq) analysis has provided compelling evidence for the involvement of differentiated medial SMC and adventitial/medial progenitors derived from SMCs in progressing intimal thickening.Despite these insights, the putative role of resident vascular stem cells that do not originate from medial SMCs in promoting intimal thickening remains controversial. Light as a diagnostic and prognostic tool has several advantages including high sensitivity, non-destructive measurement, small or even non-invasive analysis and low limits of detection for early detection of disease phenotypes. In combination with microfluidics, photonics enables real time measurement of single cells in very small sample volumes. To accompany these photonic platforms, deep learning, a subset of supervised machine learning based primarily on artificial neural network geometries, has rapidly grown as a predictive method t...