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Blunted Arterial Blood Pressure Responses to Whole‐Body Cold Stress in Individuals with Multiple Sclerosis
Author(s) -
Allen Dustin Ryan,
Huang Mu Ryan,
Frohman Elliot M,
Davis Scott L
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.763.25
Subject(s) - medicine , blood pressure , heart rate , laser doppler velocimetry , cardiology , photoplethysmogram , mean arterial pressure , anesthesia , heart rate variability , cold pressor test , blood flow , filter (signal processing) , computer science , computer vision
Multiple sclerosis (MS) is a neurological disease in which demyelination disrupts signal transmission and/or integration within the central nervous system. Reduced resting MSNA has been previously reported in MS patients (Keller et al., 2014). The aim of this study was to test the hypothesis that individuals with MS will have blunted sympathetic‐mediated responses to a whole‐body cold stress stimulus compared to healthy controls (CON). Ten subjects with relapsing‐remitting MS (age, 35±7 years old; height: 163±9 cm; weight: 64±12 kg; BSA: 1.7±0.2 m 2 ) and 4 healthy controls (31±5 years old; height: 168±6 cm; weight: 66±14 kg; BSA: 1.7±0.2 m 2 ) participated in the study. Subjects were instrumented with a tube‐lined water perfusion suit in which they were exposed to a thermoneutral (34 °C circulating water) condition for a baseline period of 10 minutes, followed by a 3‐minute whole‐body cold stress (5 °C circulating water) condition. Skin blood flow (laser‐Doppler flowmetry), beat‐to‐beat arterial pressure (photoplethysmography), heart rate (ECG), and mean skin temperature were continuously measured. Cutaneous vascular conductance was calculated from the ratio of laser‐Doppler flux to mean arterial pressure (CVC) and normalized to maximal responses obtained by local heating at 42 °C following cooling (%CVC max ). Mean arterial pressures (MAP) were derived during the final minute of baseline and cooling. There were no differences in ΔLDF flux (CON: −2.83±3.76; MS: −3.73±4.29, p=0.72), ΔCVC (CON: −0.05± 0.06; MS: −0.05±0.06, p=0.89), and Δ%CVC max (CON: −2.43±3.75; MS: −0.24, p=0.12) from baseline to cooling. However, there was a significant difference in ΔMAP between groups (CON: 12.17±9.70; MS: −0.99±7.00, p=0.01). While cutaneous vasoconstrictor responsiveness was similar between groups, these data suggest individuals with MS exhibit reduced sympathetic‐mediated changes in blood pressure in response to a whole body cold stress. Support or Funding Information Project funded by NIH grant (R15 HL117224) and National Multiple Sclerosis Society grants (RG4043A and RG4696A)