title: Morphometric analysis of gastrocnemius muscle biopsies from patients with peripheral arterial disease: objective grading of muscle degeneration.
abstract: Peripheral arterial disease (PAD), which affects ~10 million Americans, is characterized by atherosclerosis of the noncoronary arteries. PAD produces a progressive accumulation of ischemic injury to the legs, manifested as a gradual degradation of gastrocnemius histology. In this study, we evaluated the hypothesis that quantitative morphological parameters of gastrocnemius myofibers change in a consistent manner during the progression of PAD, provide an objective grading of muscle degeneration in the ischemic limb, and correlate to a clinical stage of PAD. Biopsies were collected with a Bergström needle from PAD patients with claudication (n = 18) and critical limb ischemia (CLI; n = 19) and control patients (n = 19). Myofiber sarcolemmas and myosin heavy chains were labeled for fluorescence detection and quantitative analysis of morphometric variables, including area, roundness, perimeter, equivalent diameter, major and minor axes, solidity, and fiber density. The muscle specimens were separated into training and validation data sets for development of a discriminant model for categorizing muscle samples on the basis of disease severity. The parameters for this model included standard deviation of roundness, standard deviation of solidity of myofibers, and fiber density. For the validation data set, the discriminant model accurately identified control (80.0% accuracy), claudicating (77.7% accuracy), and CLI (88.8% accuracy) patients, with an overall classification accuracy of 82.1%. Myofiber morphometry provided a discriminant model that establishes a correlation between PAD progression and advancing muscle degeneration. This model effectively separated PAD and control patients and provided a grading of muscle degeneration within clinical stages of PAD.
authors.affiliation: Bioengineering, Wichita State University, Wichita, KS, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Cluff
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Miserlis
authors.forename: Govindarajan Konda
authors.initials: GK
authors.lastname: Naganathan
authors.forename: Iraklis I
authors.initials: II
authors.lastname: Pipinos
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Koutakis
authors.forename: Ashok
authors.initials: A
authors.lastname: Samal
authors.forename: Rodney D
authors.initials: RD
authors.lastname: McComb
authors.forename: Jeyamkondan
authors.initials: J
authors.lastname: Subbiah
authors.forename: George P
authors.initials: GP
authors.lastname: Casale
mesh_terms: D000368:Aged; D000465:Algorithms; D001706:Biopsy; D016002:Discriminant Analysis; D018450:Disease Progression; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D008954:Models, Biological; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology*; D009218:Myosins / Q000378:metabolism; D058729:Peripheral Arterial Disease / Q000473:pathology*; D012508:Sarcolemma / Q000473:pathology
chemical_list: D005456:Fluorescent Dyes; D009218:Myosins
keywords: fluorescence microscopy; imaging; linear discriminant analysis; myofiber morphology