1. Sign our petition calling on Cochrane to withdraw their review of Exercise Therapy for CFS here.
    Dismiss Notice
  2. Guest, the 'News in Brief' for the week beginning 18th March 2024 is here.
    Dismiss Notice
  3. Welcome! To read the Core Purpose and Values of our forum, click here.
    Dismiss Notice

Transcutaneous vagus nerve stimulation attenuates autoantibody-mediated cardiovagal dysfunction & inflammation in a rabbit model of [POTS], 2022, Deng

Discussion in ''Conditions related to ME/CFS' news and research' started by Andy, Feb 5, 2022.

  1. Andy

    Andy Committee Member

    Messages:
    21,808
    Location:
    Hampshire, UK
    Abstract

    Purpose
    Previous studies demonstrated M2 muscarinic acetylcholine receptor-activating autoantibodies (M2R-AAb) were present in some patients with postural tachycardia syndrome (POTS). This study examines how these autoantibodies might contribute to the pathophysiology of POTS, and whether low-level tragus stimulation (LLTS) can ameliorate autoantibody-mediated autonomic dysregulation in the rabbit.

    Methods
    Five New Zealand white rabbits were immunized with a M2R second extracellular loop peptide to produce cholinomimetic M2R-AAb. Tilt test and infusion studies were performed on conscious rabbits before immunization, 6 weeks after immunization, and 8 weeks after immunization with 2-week daily LLTS treatment. Each rabbit served as its own control.

    Results
    Compared to preimmune state, an enhanced heart rate increase and decreased parasympathetic activity upon tilting were observed in immunized rabbits. Furthermore, these rabbits demonstrated an attenuated heart rate-slowing response to infusion of the M2R orthosteric agonist arecaidine propargyl ester (APE), suggesting an inhibitory allosteric effect of M2R-AAb. There was also a significant increase in serum inflammatory cytokines in immunized rabbits. LLTS treatment suppressed the postural tachycardia, improved the sympathovagal balance with increased acetylcholine secretion, reduced the levels of inflammatory cytokines, and reversed the attenuated heart rate response to APE in immunized rabbits. No suppression of M2R-AAb expression by LLTS was found during this short-term study period. Receptor-modulating activity of M2R-AAb produced in immunized rabbits was confirmed with in vitro bioassay.

    Conclusions
    Autoantibody inhibition of cholinergic ligand activity may be involved in the development of cardiovagal dysfunction and inflammation associated with POTS, both of which can be improved by vagal stimulation.

    Paywall, https://link.springer.com/article/10.1007/s10840-022-01144-w
     
  2. Lisa108

    Lisa108 Senior Member (Voting Rights)

    Messages:
    739
    Location:
    Germany
    So they do have tiny tilt test tables for rabbits? I need to see pictures!

    It's just as absurd as not using POTS patients for this study.
     
  3. Hutan

    Hutan Moderator Staff Member

    Messages:
    26,520
    Location:
    Aotearoa New Zealand
    I've talked about tragus stimulation elsewhere. The tragus is part of the ear.

    Screen Shot 2022-04-20 at 9.54.10 am.png

    In humans, it seems it's not really known if the vagus nerve even properly goes to the tragus. It seemed that trans-cutaneous stimulation of the tragus might not even be affecting the vagal nerve. Of course, in rabbits, different ears, so, who knows. I haven't read this study, due to the paywall.
     
    Lisa108, Peter Trewhitt and Trish like this.

Share This Page