Inflammatory bowel disease (IBD) frustrates practitioners and patients alike, due to its enigmatic origins and limited treatment options.1 For both human and veterinary patients, the etiology of IBD is “multifactorial and poorly understood.”2 As stated by the Colorado State University (CSU) One Health Institute, “Previously, it was thought diet and stress were primary causes of IBD, but these are now recognized as risk factors that aggravate but do not cause IBD. Researchers now recognize an immune system malfunction as the main culprit leading to IBD. Similar to the autoimmune reactions seen with an allergic response, the lining of the intestine is invaded by inflammatory cells. This abnormal immune response leads to destruction of normal cell numbers and function within the tissue of the GI tract, resulting in intestinal villi atrophy, which interferes with the ability to digest and absorb nutrients.”2 Treatment for humans, horses, cats, and dogs typically consists of anti-inflammatory and immunomodulatory medications, along with the occasional antibiotic. Dietary changes, nutraceuticals, and vitamins may assist in reducing antigenic stimulation of the immune system. However, “[t]he severity of IBD and the fact that many affected human and animal patients continue to have symptoms, despite or because of current available therapies, demonstrates a strong need for increased understanding and novel treatment approaches for the disease.”2 Fifteen-year-old neutered male cat, Zeno, receives acupuncture and laser treatments. This demonstrates how comfortable cats can be while receiving care. Photo courtesy Dr. Narda G. Robinson Looking into integrative medicine About half of humans with IBD seek relief through integrative medical care, such as acupuncture.3 Medical acupuncture, in particular, stands out as an evidence-based, cost-effective, and safe nonpharmacologic option. A systematic review and meta-analysis found evidential support for acupuncture’s ability to relieve IBD symptoms and modulate blood levels of inflammatory markers.4 Medical acupuncture targets the putative etiology of IBD, i.e. vagal dysregulation. In IBD, the vagus nerve has become dysfunctional in one of its main jobs—that of maintaining physiologic homeostasis.5 Anatomically, the vagus nerve constitutes a key component of the parasympathetic limb of the autonomic nervous system. It originates in the brain stem and courses extensively throughout the body. Named after the Latin term for “wanderer,” the vagus nerve innervates nearly every internal organ. Its composition of 80 percent afferent and 20 percent efferent fibers highlights its role as “messenger,” ferrying information from the periphery to somato-autonomic convergence centers in the brainstem, such as the nucleus tractus solitarius. This, then, stimulates an autoregulatory response designed to correct the disturbance. The vagus nerve’s “spidey senses” allow it to detect three potent promoters of chronic disease: oxidative stress, inflammation, and sympathetic over-activation.6 When the vagus nerve functions adequately, these incoming signals trigger the “vagal anti-inflammatory reflex,” a multi-pronged response that endogenously controls inflammation and circulatory compromise. This response includes: Neuroendocrine effects on the hypothalamic-pituitary-adrenal (HPA) axis that increase cortisol secretion Neuroimmunomodulatory influences on immune cells, such as monocytes, that inhibit the synthesis of inflammatory cytokines, and Reversing sympathetic nervous system-induced vasoconstriction, thereby improving circulation and oxygenation The vagus nerve also interfaces with the microbiome through the brain-gut-microbiota axis (BGMA), highlighting yet another mechanism through which vagus nerve stimulation may aid patients with IBD. As described by Bellocchi et al.,7 “Gut microbiota can directly interact with the [enteric nervous system (ENS)] and indirectly modulate the BGA through neuroendocrine and neuroimmune pathways, all together considered the “brain-gut–microbiota” axis. If these mechanisms undergo a dysfunction, an imbalance of this system leads to clinical alteration of the [gastrointestinal tract], especially with [irritable bowel syndrome] development. Moreover, the microbiota is directly associated with mental health disorders as demonstrated in knock-out mice models in which the absence of intestinal microbiota influences the development of behavior, along with neurochemical changes in the brain. Microbiota alterations can modulate both the brain functions and the ANS through the vagus nerve, sending signals to the CNS and vice versa.” Further, we now see where the nervous, immune, and digestive systems interplay: “Some vagal afferent fibers come into close touch with intestinal mucosal mast cells as they go to the tips of the jejunal villi. These findings offer the microanatomical foundation for mast cells in the gastrointestinal mucosa to communicate directly with the central nervous system. It is interesting to note the efferent [vagal nerve] interacts with enteric neurons instead of directly connecting to the gut’s resident macrophages. Therefore, enteric neurons rather than vagal efferent fibers directly mediate the vagal regulation of these intestinal macrophages. Pro-inflammatory cytokines that stimulate vagal afferents cause the activation of vagal efferents, which prevents tissue macrophages from releasing these cytokines, including [tumor necrosis factor] and other pro-inflammatory cytokines…”8 How does all this relate to acupuncture? Regulation (neuromodulation) of the central, peripheral, and autonomic nervous systems constitutes the key mechanism of medical acupuncture. When vagal nerve activity falls short, acupuncture can boost its activity and promote its return to function. This, then, allows the body’s endogenous reparative capacity to more competently address the disturbance, thereby reducing reliance on medications. A 2019 article on acupuncture, published in Inflammatory Bowel Diseases,9 noted, “Acupuncture has been shown to decrease disease activity and inflammation via increase of vagal activity in inflammatory bowel disease. Acupuncture has demonstrated beneficial roles in the regulation of gut dysbiosis, intestinal barrier function, visceral hypersensitivity, gut motor dysfunction, depression/anxiety, and pain, all of which are factors that can significantly impact quality of life in patients with inflammatory bowel disease. A number of clinical trials have been performed to investigate the therapeutic effects of acupuncture in ulcerative colitis and Crohn’s disease. Although the data from these trials are promising, more studies are needed given the heterogeneous and multifactorial aspects of inflammatory bowel disease. There is also an important need to standardize acupuncture methodology, study designs, and outcome measurements.” Improving the quality of acupuncture research requires, in large part, moving away from outdated and inaccurate views of how acupuncture works, such as by invoking mystical forces like chi, yin, and yang. Instead, when we understand how acupuncture works through the lens of neuromodulation, we can then test hypotheses based on measuring objective outcomes. A look at the evidence A scientific approach to acupuncture elevates the quality of translational research. It does so by identifying the innervation of each acupuncture point included in a protocol and ensuring similarity across species. This is vital because the physiologic changes induced by acupuncture stimulation depend on which nerves become activated. For acupuncture treatment of IBD, practitioners should ideally target two main areas. These comprise: 1) A point on the pelvic limb, known as Stomach 36 (ST 36), which regulates digestive processes, and 2) points on the back, to address the reverberating discomfiture afflicting the back and the intestines, common in IBD patients. The first site, ST 36 (Zusanli), is located near the motor point of the cranial tibialis muscle, supplied by the deep fibular nerve (see Figures 1 and 2). A murine study of electroacupuncture (EA) at ST 36 in a rodent model of IBD revealed that treatment reversed inflammation and leukocyte infiltration. It also normalized the levels of previously elevated inflammatory cytokines and normalized the colon’s tight junctions.10 Figure 1.This anatomical acupuncture chart highlights three types of points for cats with IBD. Paraspinal points address somatic discomfort in the lumbar region; they also neuromodulate lumbar spinal cord segments, working to minimize referred pain from internal organs by means of viscerosomatic reflexes. The “Bai Hui” acupuncture point resides at the dorsal midline along the lumbosacral junction and overlies the lumbosacral plexus. Somatic afferent stimulation at Bai Hui induces autonomic neuromodulation of pelvic viscera. Stomach 36, or ST 36, activates in long-loop reflexes through the nucleus tractus solitarius in the medulla oblongata, supporting normalization of vagal nerve impulses. Photo courtesy Dr. Narda G. Robinson Figure 2.This photo depicts acupuncture points shown in Figure 1 as found on Leonard, an 11-year-old neutered male cat. Photo courtesy Dr. Narda G. Robinson Research in rats with experimentally induced colitis showed EA at ST 36 alleviated somatic pain by inhibiting surface neurogenic inflammation and sympathetic sprouting into the dorsal root ganglion.11 The authors suggest EA could benefit colitis patients with referred pain. For more of the psychological aspects of IBD, EA at ST 36 connected to a more distal point on the crus supplied by the tibial nerve, called Sanyinjiao (“Three Yin Intersection,” or SP 6), attenuated anxiety and depression-like behavior in colitis-model rats.12 As mentioned above and shown in the accompanying figures, medical acupuncturists frequently include points on the back and trunk to address muscle and soft tissue pain. From an osteopathic and neuroanatomic perspective, visceral inflammation may induce back pain due to viscerosomatic reflexes in the spinal cord. That is, activation of nociceptors in internal organs stimulates sites in the spinal cord that converge with neural pathways from thoracic, lumbar, and sacral spinal cord segments, causing pain from the gut to be perceived as originating from the back. Elevated levels of inflammatory mediators circulating in the blood and residing in tissues could also precipitate pain in somatic structures and visceral organs. In many cases, massage and photomedicine (laser therapy or light-emitting diodes) may augment or substitute for acupuncture, as they can also activate and benefit the vagus nerve. For more information on incorporating medical acupuncture in the clinic environment, see the case report by Julie Hermansen, DVM, cVMA, on medical acupuncture for IBD in a 13-year-old feline patient at the Curacore website. Narda G. Robinson, DO, DVM, MS, FAAMA, practices osteopathic medicine and veterinary medicine. Dr. Robinson taught science-based integrative medicine at the Colorado State University College of Veterinary Medicine and Biomedical Sciences for 20 years. In 2016, Robinson established her academy in Fort Collins, Colo., where she teaches medical acupuncture, integrative rehabilitation, medical massage, and other integrative medical approaches. Columnists’ opinions do not necessarily reflect those of Veterinary Practice News. References Cornell Feline Health Center. Inflammatory Bowel Disease. December 14, 2020. Accessed at April 14, 2025 at https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/inflammatory-bowel-disease. Colorado State University One Health Institute. Inflammatory Bowel Disease. Accessed at https://onehealth.colostate.edu/2020/12/14/inflammatory-bowel-disease/ on April 14, 2025. Song G, Fiocchi C, and Achkar J-P. Acupuncture in Inflammatory Bowel Disease. Inflamm Bowel Dis.2019;25(7): 1129-1139. Yang X, He M, Tang Q, et al. Assessment of anti-inflammatory efficacy of acupuncture in patients with inflammatory bowel disease: A systematic review and meta-analysis. Complementary Therapies in Medicine. 2023;74:102946. Fornaro R, Actis GC, Caviglia GP, et al. Review. Inflammatory Bowel Disease: Role of Vagus Nerve Simulation. J Clin Med. 2022,11, 5690. https://doi.org/10.3390/jcm11195690. Gidron Y, Deschepper R, De Couck M, et al. The vagus nerve can predict and possibly modulate non-communicable chronic diseases: Introducing a neuroimmunological paradigm to public health. J Clin Med. 2018;7(10): 371. Bellocchi C, Carandina A, Montinaro B, et al. Review. The interplay between autonomic nervous system and inflammation across systemic autoimmune diseases. Int J MolSci. 2022, 23, 2449. https://doi.org/10.3390/ijms23052449. Fornaro R, Actis GC, Caviglia GP, et al. Review. Inflammatory Bowel Disease: Role of Vagus Nerve Simulation. J Clin Med. 2022,11, 5690. https://doi.org/10.3390/jcm11195690. (Op cit). Song G, Fiocchi C, and Achkar J-P. Acupuncture in Inflammatory Bowel Disease. Inflamm Bowel Dis.2019;25(7): 1129-1139. Op cit. Chen Y, Cai M, Shen B, et al. Electroacupuncture at Zusanli regulates the pathological phenotype of inflammatory bowel disease by modulating the NLRP3 inflammasome pathway. Immun Inflamm Dis. 2024;12:e1366. Wang Y-L, Zhu H-Y, Lv X-Q, et al. Electroacupuncture Zusanli (ST36) Relieves Somatic Pain in Colitis Rats by Inhibiting Dorsal Root Ganglion Sympathetic-Sensory Coupling and Neurogenic Inflammation. Neural Plasticity. 2023; Article ID 9303419. https://doi.org/10.1155/2023/9303419 Zhou F, Jiang H, Kong N, et al. Electroacupuncture Attenuated Anxiety and Depression-Like Behavior via Inhibition of Hippocampal Inflammatory Response and Metabolic Disorders in TNBS-Induced IBD Rats. Oxid Med Cell Longev. 2022 Jan 18:2022:8295580. doi: 10.1155/2022/8295580.
