1
|
Kralj L, Potočnik N, Lenasi H. Evaluating transient phenomena by wavelet analysis: early recovery to exercise. Am J Physiol Heart Circ Physiol 2024; 326:H96-H102. [PMID: 37921668 PMCID: PMC11213473 DOI: 10.1152/ajpheart.00558.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/04/2023]
Abstract
Wavelet analysis (WA) provides superior time-frequency decomposition of complex signals than conventional spectral analysis tools. To illustrate its usefulness in assessing transient phenomena, we applied a custom-developed WA algorithm to laser-Doppler (LD) signals of the cutaneous microcirculation measured at glabrous (finger pulp) and nonglabrous (forearm) sites during early recovery after dynamic exercise. This phase, importantly contributing to the establishment of thermal homeostasis after exercise cessation, has not been adequately explored because of its complex, transient form. Using WA, we decomposed the LD signals measured during the baseline and early recovery into power spectra of characteristic frequency intervals corresponding to endothelial nitric oxide (NO)-dependent, neurogenic, myogenic, respiratory, and cardiac physiological influence. Assessment of relative power (RP), defined as the ratio between the median power in the frequency interval and the median power of the total spectrum, revealed that endothelial NO-dependent (5.87 early recovery; 1.53 baseline; P = 0.005; Wilcoxon signed-rank test) and respiratory (0.71 early recovery; 0.40 baseline; P = 0.001) components were significantly increased, and myogenic component (1.35 early recovery; 1.83 baseline; P = 0.02) significantly decreased during early recovery in the finger pulp. In the forearm, only the RP of the endothelial NO-dependent (1.90 early recovery; 0.94 baseline; P = 0.009) component was significantly increased. WA presents an irreplaceable tool for the assessment of transient phenomena. The relative contribution of the physiological mechanisms controlling the microcirculatory response in the early recovery phase appears to differ in glabrous and nonglabrous skin when compared with baseline; moreover, the endothelial NO-dependent influence seems to play an important role.NEW & NOTEWORTHY We address the applicability of wavelet analysis (WA) in evaluating transient phenomena on a model of early recovery to exercise, which is the only exercise-associated phase characterized by a distinct transient shape and as such cannot be assessed using conventional tools. Our WA-based algorithm provided a reliable spectral decomposition of laser-Doppler (LD) signals in early recovery, enabling us to speculate roughly on the mechanisms involved in the regulation of skin microcirculation in this phase.
Collapse
Affiliation(s)
- Lana Kralj
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Nejka Potočnik
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Helena Lenasi
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| |
Collapse
|
2
|
Samils L, Henricson J, Strömberg T, Fredriksson I, Iredahl F. Workload and sex effects in comprehensive assessment of cutaneous microcirculation. Microvasc Res 2023; 148:104547. [PMID: 37192688 DOI: 10.1016/j.mvr.2023.104547] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/25/2023] [Accepted: 05/11/2023] [Indexed: 05/18/2023]
Abstract
INTRODUCTION Workload and sex-related differences have been proposed as factors of importance when evaluating the microcirculation. Simultaneous assessments with diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) enable a comprehensive evaluation of the microcirculation. The aim of the study was to compare the response between sexes in the microcirculatory parameters red blood cell (RBC) tissue fraction, RBC oxygen saturation, average vessel diameter, and speed-resolved perfusion during baseline, cycling, and recovery, respectively. METHODS In 24 healthy participants (aged 20 to 30 years, 12 females), cutaneous microcirculation was assessed by LDF and DRS at baseline, during a workload generated by cycling at 75 to 80 % of maximal age-predicted heart rate, and recovery, respectively. RESULTS Females had significantly lower RBC tissue fraction and total perfusion in forearm skin microcirculation at all phases (baseline, workload, and recovery). All microvascular parameters increased significantly during cycling, most evident in RBC oxygen saturation (34 % increase on average) and perfusion (9-fold increase in total perfusion). For perfusion, the highest speeds (>10 mm/s) increased by a factor of 31, whereas the lowest speeds (<1 mm/s) increased by a factor of 2. CONCLUSION Compared to a resting state, all studied microcirculation measures increased during cycling. For perfusion, this was mainly due to increased speed, and only to a minor extent due to increased RBC tissue fraction. Skin microcirculatory differences between sexes were seen in RBC concentration and total perfusion.
Collapse
Affiliation(s)
- Linda Samils
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden
| | - Joakim Henricson
- Department of Emergency Medicine in Linköping, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Fredrik Iredahl
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden.
| |
Collapse
|
3
|
Kralj L, Lenasi H. Wavelet analysis of laser Doppler microcirculatory signals: Current applications and limitations. Front Physiol 2023; 13:1076445. [PMID: 36741808 PMCID: PMC9895103 DOI: 10.3389/fphys.2022.1076445] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/28/2022] [Indexed: 01/21/2023] Open
Abstract
Laser Doppler flowmetry (LDF) has long been considered a gold standard for non-invasive assessment of skin microvascular function. Due to the laser Doppler (LD) microcirculatory signal's complex biological and physiological context, using spectral analysis is advisable to extract as many of the signal's properties as feasible. Spectral analysis can be performed using either a classical Fourier transform (FT) technique, which has the disadvantage of not being able to localize a signal in time, or wavelet analysis (WA), which provides both the time and frequency localization of the inspected signal. So far, WA of LD microcirculatory signals has revealed five characteristic frequency intervals, ranging from 0.005 to 2 Hz, each of which being related to a specific physiological influence modulating skin microcirculatory response, providing for a more thorough analysis of the signals measured in healthy and diseased individuals. Even though WA is a valuable tool for analyzing and evaluating LDF-measured microcirculatory signals, limitations remain, resulting in a lack of analytical standardization. As a more accurate assessment of human skin microcirculation may better enhance the prognosis of diseases marked by microvascular dysfunction, searching for improvements to the WA method is crucial from the clinical point of view. Accordingly, we have summarized and discussed WA application and its limitations when evaluating LD microcirculatory signals, and presented insight into possible future improvements. We adopted a novel strategy when presenting the findings of recent studies using WA by focusing on frequency intervals to contrast the findings of the various studies undertaken thus far and highlight their disparities.
Collapse
Affiliation(s)
- Lana Kralj
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Helena Lenasi
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia,*Correspondence: Helena Lenasi,
| |
Collapse
|
4
|
Reynès C, Beaume JB, Latil-Plat F, Ennaifer H, Rocher L, Antoine-Jonville S, Benamo E, Knapp Y, Vinet A. Concomitant Peripheral Neuropathy and Type 2 Diabetes Impairs Postexercise Cutaneous Perfusion and Flowmotion. J Clin Endocrinol Metab 2021; 106:e3979-e3989. [PMID: 34111245 DOI: 10.1210/clinem/dgab414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Indexed: 12/18/2022]
Abstract
CONTEXT Type 2 diabetes and peripheral neuropathy exhibit microvascular dysfunction at rest. However, data regarding their microvascular perfusion during exercise remain scarce. OBJECTIVE This study investigated changes in microvascular perfusion during postexercise recovery in those with type 2 diabetes, with or without peripheral neuropathy, as well as in healthy controls and those with obesity. METHODS Skin blood perfusion was assessed in each group using laser Doppler flowmetry (LDF) and laser speckle contrast imaging before and immediately after a 6-minute walking test. LDF recordings underwent wavelet transformation to allow specific control mechanisms of blood perfusion to be studied (eg, endothelial nitric oxide-independent and -dependent, neurogenic, myogenic, respiratory, and cardiac mechanisms). RESULTS Skin blood perfusion increased after exercise in all groups (22.3 ± 28.1% with laser speckle contrast imaging and 22.1 ± 52.5% with LDF). Throughout postexercise recovery, the decrease was blunted in those with subclinical peripheral neuropathy and confirmed peripheral neuropathy when compared to the other 3 groups. After exercise, total spectral power increased in all groups. The relative contributions of each endothelial band was lower in those with confirmed peripheral neuropathy than in the healthy controls and those with obesity (nitric oxide-dependent function: 23.6 ± 8.9% vs 35.5 ± 5.8% and 29.3 ± 8.8%, respectively; nitric oxide-independent function: 49.1 ± 23.7% vs 53.3 ± 10.4% and 64.6 ± 11.4%, respectively). The neurogenic contribution decreased less in those with confirmed peripheral neuropathy and in those with type 2 diabetes alone, compared to those with subclinical peripheral neuropathy and those with obesity (-14.5 ± 9.9% and -12.2 ± 6.1% vs -26.5 ± 4.7% and -21.7 ± 9.4%, respectively). CONCLUSION Peripheral neuropathy, whatever the stage, altered the microvascular response to exercise via impaired endothelial and neurogenic mechanisms.
Collapse
Affiliation(s)
- Cécile Reynès
- Avignon Université, LAPEC EA4278, F-84000, Avignon, France
| | | | - Françoise Latil-Plat
- Service endocrinologie et maladies métaboliques, Centre hospitalier Henri Duffaut, F-84000, Avignon, France
| | - Houda Ennaifer
- Service endocrinologie et maladies métaboliques, Centre hospitalier Henri Duffaut, F-84000, Avignon, France
| | - Laure Rocher
- Service endocrinologie et maladies métaboliques, Centre hospitalier Henri Duffaut, F-84000, Avignon, France
| | | | - Eric Benamo
- Service endocrinologie et maladies métaboliques, Centre hospitalier Henri Duffaut, F-84000, Avignon, France
| | - Yannick Knapp
- Avignon Université, LAPEC EA4278, F-84000, Avignon, France
| | - Agnès Vinet
- Avignon Université, LAPEC EA4278, F-84000, Avignon, France
| |
Collapse
|
5
|
Jan YK, Liao F, Cheing GL, Pu F, Ren W, Choi HM. Differences in skin blood flow oscillations between the plantar and dorsal foot in people with diabetes mellitus and peripheral neuropathy. Microvasc Res 2019; 122:45-51. [DOI: 10.1016/j.mvr.2018.11.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 11/07/2018] [Accepted: 11/07/2018] [Indexed: 12/11/2022]
|
6
|
Saemann L, Lachner K, Wenzel F. Cardiac frequency and cutaneous microcirculation during and after exercising in the view of physical condition. Clin Hemorheol Microcirc 2017; 67:221-227. [PMID: 28885197 DOI: 10.3233/ch-179203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION In the field of cardiovascular diseases an ergometer test is a common diagnostical method in which a change in microcirculation can be reached. In this paper cardiac frequency and cutaneous microcirculation during and after exercising will be compared with each other. MATERIALS AND METHODS The cutaneous microcirculation of 6 healthy volunteers (2 females, 4 males) is measured. As an instrument the PeriFlux 5000 combined with a Laser-Doppler-Flow(LDF)-Probe (Perimed Instruments) is used. The cardiac frequency (CF) is measured by the POLAR T31 sensor and as an ergometer the ERGO-FIT ® 457 is used. RESULTS The mean initial LDF (97,7±57,3 PU) decreases at the beginning (64,5±21,7 PU), increases during theexercise, reaches its maximum (247,8±82,1 PU) after the end of the exercise and drops to lower values (256,4±69,5 PU)after a few minutes. Contrasting to the LDF the mean initial CF (86±22/min) increases at the beginning (97±9/min),furthermore during the whole exercise (103±9/min) and then falls after having finished the exercise (96±3/min).Furthermore, during regeneration, one can see the CF decreasing towards its initial value, while LDF reaches its maximum. CONCLUSION In further studies, realized with volunteers with well-known levels of physical condition, a directconnection between cutaneous microcirculation and physical condition might be found.
Collapse
Affiliation(s)
- Lars Saemann
- Furtwangen University, Villingen-Schwenningen, Germany
| | - Karin Lachner
- Furtwangen University, Villingen-Schwenningen, Germany
| | - Folker Wenzel
- Furtwangen University, Villingen-Schwenningen, Germany
| |
Collapse
|
7
|
Gerk U, Mrowietz C, Sternitzky R, Franke RP, Spitzer SG, Jung F. Effect of Ioxaglate on the cutaneous microcirculation in patients with coronary artery disease: Randomized, double blind, placebo-controlled study. Clin Hemorheol Microcirc 2017; 64:297-304. [PMID: 28128751 DOI: 10.3233/ch-168101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Radiographic contrast media (RCM) can initiate microcirculatory disorders. This study was performed to investigate effects of Ioxaglate on the cutaneous microcirculation. The investigation was carried out as prospective randomized double-blind comparison in parallel-group design on two groups of n = 10 patients each who had to undergo a diagnostic coronary angiography.The confirmatory parameter of the study was mean erythrocyte capillary velocity [vRBC in mm/sec]. VRBC in the ipsilateral nail-fold capillaries was recorded continuously for 3 min before and 6 min after injection of RCM or isotonic saline solution in the A. axillaris respectively, and was evaluated off-line.VRBC in nailfold capillaries was found to be decreased by Ioxaglate by 34% 150 seconds after injection, while isotonic NaCl solution immediately induced a slight increase of 14%.
Collapse
Affiliation(s)
- U Gerk
- Krankenhaus Dresden-Friedrichstadt, II. Medizinische Klinik, Dresden, Germany
| | - C Mrowietz
- Institute for Heart and Circulation Research, Eißendorfer Pferdeweg, Hamburg-Harburg, Germany
| | - R Sternitzky
- Praxisklinik Herz und Gefäße, Dresden, and Brandenburgische Technische Universität (BTU), Cottbus-Senftenberg, Germany
| | - R P Franke
- Department of Biomaterials, Central Institute for Biomedical Engineering, University of Ulm, Ulm, Germany
| | - S G Spitzer
- Praxisklinik Herz und Gefäße, Dresden, and Brandenburgische Technische Universität (BTU), Cottbus-Senftenberg, Germany
| | - F Jung
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany
| |
Collapse
|