title: Combining laser-Doppler flowmetry measurements with spectral analysis to study different microcirculatory effects in human prediabetic and diabetic subjects.
abstract: We aimed to identify the microcirculatory regulatory mechanisms in diabetic and prediabetic humans using a noninvasive method combining spectral analysis with laser-Doppler flowmetry (LDF) measurements on the skin surface. LDF signals were measured by a moorVMS-LDF device to measure the microcirculatory blood flow flux with a time constant of 0.001 s, a cutoff frequency of 14.9 kHz, and a sampling frequency of 40 Hz. The laser operating wavelength and output power were 400-700 nm and 6 mW, respectively. LDF signals were obtained noninvasively in 115 subjects, who were assigned to three groups (diabetic, prediabetic, and normal) according to the results of the oral glucose tolerance tests. A Morlet mother wavelet transform was applied to the measured 20-min LDF signals, and periodic oscillations with five characteristic frequency peaks were obtained within the following frequency bands: 0.0095-0.02, 0.02-0.06, 0.06-0.15, 0.15-0.4, and 0.4-1.6 Hz (defined as FR1-FR5), respectively. The relative energy contribution (REC) of FR1 was significantly smaller (by using the Kruskal-Wallis test followed by Dunn's multiple-comparison tests) in diabetic subjects than in normal subjects. The REC of FR2-FR3 was significantly smaller in diabetic and prediabetic subjects than in normal subjects. The REC of FR1-FR3 from normal to prediabetic and diabetic subjects showed a progressive decrease. The present findings may aid in the development of a noninvasive method for the early detection of prediabetes and the monitoring of disease progression. This may be useful in preventing disease progression and reducing the risk of concomitant end-organ damage.
authors.affiliation: Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, Taiwan.|Department of Emergency Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Hsiao-Feng
authors.initials: HF
authors.lastname: Hu
authors.affiliation: Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Rd. Keelung, Taipei, 10607, Taiwan. hhsiu@mail.ntust.edu.tw.
authors.forename: Hsin
authors.initials: H
authors.lastname: Hsiu
authors.affiliation: Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Rd. Keelung, Taipei, 10607, Taiwan.
authors.forename: Ciao-Jyuan
authors.initials: CJ
authors.lastname: Sung
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Chien-Hsing
authors.initials: CH
authors.lastname: Lee
mesh_terms: D000328:Adult; D001794:Blood Pressure; D003920:Diabetes Mellitus / Q000503:physiopathology*; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000379:methods*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D011236:Prediabetic State / Q000503:physiopathology*; D013057:Spectrum Analysis / Q000379:methods*; D058067:Wavelet Analysis
keywords: Blood flow; Diabetes; Laser Doppler; Microcirculation; Prediabetes; Spectral analysis