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Yang S, Wu YR, Zhan Z, Pan YH, Jiang JF. State- and frequency-dependence in autonomic rebalance mediated by intradermal auricular electroacupuncture stimulation. Front Neurosci 2024; 18:1367266. [PMID: 38846714 PMCID: PMC11153749 DOI: 10.3389/fnins.2024.1367266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 05/09/2024] [Indexed: 06/09/2024] Open
Abstract
Background Vagus nerve stimulation (VNS) improves diseases such as refractory epilepsy and treatment-resistant depression, likely by rebalancing the autonomic nervous system (ANS). Intradermal auricular electro-acupuncture stimulation (iaES) produces similar effects. The aim of this study was to determine the effects of different iaES frequencies on the parasympathetic and sympathetic divisions in different states of ANS imbalance. Methods We measured heart rate variability (HRV) and heart rate (HR) of non-modeled (normal) rats with the treatment of various frequencies to determine the optimal iaES frequency. The optimized iaES frequency was then applied to ANS imbalance model rats to elucidate its effects. Results 30 Hz and 100 Hz iaES clearly affected HRV and HR in normal rats. 30 Hz iaES increased HRV, and decreased HR. 100 Hz iaES decreased HRV, and increased HR. In sympathetic excited state rats, 30 Hz iaES increased HRV. 100 Hz iaES increased HRV, and decreased HR. In parasympathetic excited state rats, 30 Hz and 100 Hz iaES decreased HRV. In sympathetic inhibited state rats, 30 Hz iaES decreased HRV, while 100 Hz iaES decreased HR. In parasympathetic inhibited rats, 30 Hz iaES decreased HR and 100 Hz iaES increased HRV. Conclusion 30 Hz and 100 Hz iaES contribute to ANS rebalance by increasing vagal and sympathetic activity with different amplifications. The 30 Hz iaES exhibited positive effects in all the imbalanced states. 100 Hz iaES suppressed the sympathetic arm in sympathetic excitation and sympathetic/parasympathetic inhibition and suppressed the vagal arm and promoted the sympathetic arm in parasympathetic excitation and normal states.
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Affiliation(s)
| | | | | | | | - Jin-Feng Jiang
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
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Alvarez MR, Alkaissi H, Rieger AM, Esber GR, Acosta ME, Stephenson SI, Maurice AV, Valencia LMR, Roman CA, Alarcon JM. The immunomodulatory effect of oral NaHCO 3 is mediated by the splenic nerve: multivariate impact revealed by artificial neural networks. J Neuroinflammation 2024; 21:79. [PMID: 38549144 PMCID: PMC10976719 DOI: 10.1186/s12974-024-03067-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/18/2024] [Indexed: 04/02/2024] Open
Abstract
Stimulation of the inflammatory reflex (IR) is a promising strategy for treating systemic inflammatory disorders. Recent studies suggest oral sodium bicarbonate (NaHCO3) as a potential activator of the IR, offering a safe and cost-effective treatment approach. However, the mechanisms underlying NaHCO3-induced anti-inflammatory effects remain unclear. We investigated whether oral NaHCO3's immunomodulatory effects are mediated by the splenic nerve. Female rats received NaHCO3 or water (H2O) for four days, and splenic immune markers were assessed using flow cytometry. NaHCO3 led to a significant increase (p < 0.05, and/or partial eta squared > 0.06) in anti-inflammatory markers, including CD11bc + CD206 + (M2-like) macrophages, CD3 + CD4 + FoxP3 + cells (Tregs), and Tregs/M1-like ratio. Conversely, proinflammatory markers, such as CD11bc + CD38 + TNFα + (M1-like) macrophages, M1-like/M2-like ratio, and SSChigh/SSClow ratio of FSChighCD11bc + cells, decreased in the spleen following NaHCO3 administration. These effects were abolished in spleen-denervated rats, suggesting the necessity of the splenic nerve in mediating NaHCO3-induced immunomodulation. Artificial neural networks accurately classified NaHCO3 and H2O treatment in sham rats but failed in spleen-denervated rats, highlighting the splenic nerve's critical role. Additionally, spleen denervation independently influenced Tregs, M2-like macrophages, Tregs/M1-like ratio, and CD11bc + CD38 + cells, indicating distinct effects from both surgery and treatment. Principal component analysis (PCA) further supported the separate effects. Our findings suggest that the splenic nerve transmits oral NaHCO3-induced immunomodulatory changes to the spleen, emphasizing NaHCO3's potential as an IR activator with therapeutic implications for a wide spectrum of systemic inflammatory conditions.
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Affiliation(s)
- Milena Rodriguez Alvarez
- School of Graduate Studies & Department of Internal Medicine, Division of Rheumatology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA.
- Department of Rheumatology, SUNY Downstate Health Sciences University, 450 Clarkson Ave, Brooklyn, NY, 11203, USA.
| | - Hussam Alkaissi
- Division of Diabetes, Endocrinology, and Metabolic Diseases, NIH/NIDDK, Bethesda, MD, USA
| | - Aja M Rieger
- Department of Medical Microbiology and Immunology, University of Alberta, Alberta, Canada
| | - Guillem R Esber
- Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, Canada
| | - Manuel E Acosta
- Mathematics and Computer Sciences Department, Barry University, Miami, FL, USA
| | - Stacy I Stephenson
- Division of Comparative Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Allison V Maurice
- Division of Comparative Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | | | - Christopher A Roman
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Juan Marcos Alarcon
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
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Alvarez MR, Alarcon JM, Roman CA, Lazaro D, Bobrowski-Khoury N, Baena-Caldas GP, Esber GR. Can a basic solution activate the inflammatory reflex? A review of potential mechanisms, opportunities, and challenges. Pharmacol Res 2023; 187:106525. [PMID: 36441036 DOI: 10.1016/j.phrs.2022.106525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/09/2022] [Accepted: 10/25/2022] [Indexed: 11/24/2022]
Abstract
Stimulation of the inflammatory reflex (IR) is a promising strategy to treat systemic inflammatory disorders. However, this strategy is hindered by the cost and side effects of traditional IR activators. Recently, oral intake of sodium bicarbonate (NaHCO3) has been suggested to activate the IR, providing a safe and inexpensive alternative. Critically, the mechanisms whereby NaHCO3 might achieve this effect and more broadly the pathways underlying the IR remain poorly understood. Here, we argue that the recognition of NaHCO3 as a potential IR activator presents exciting clinical and research opportunities. To aid this quest, we provide an integrative review of our current knowledge of the neural and cellular pathways mediating the IR and discuss the status of physiological models of IR activation. From this vantage point, we derive testable hypotheses on potential mechanisms whereby NaHCO3 might stimulate the IR and compare NaHCO3 with classic IR activators. Elucidation of these mechanisms will help determine the therapeutic value of NaHCO3 as an IR activator and provide new insights into the IR circuitry.
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Affiliation(s)
- Milena Rodriguez Alvarez
- Department of Internal Medicine, Division of Rheumatology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA.
| | - Juan Marcos Alarcon
- Department of Pathology, The Robert F. Furchgott Center for Neural and Behavioral Science, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
| | - Christopher A Roman
- Department of Cell Biology, State University of New York (SUNY) Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Deana Lazaro
- Division of Rheumatology, Department of Internal Medicine, Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY, USA
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