Emerging Treatment Pathways in Neuroimmune Endometriosis: The Science Behind the Next Generation of Non-Hormonal Care | ESSI

Emerging Treatment Pathways in Neuroimmune Endometriosis

Key Takeaways

• Endometriosis is increasingly understood as a neuroimmune disease, not just a hormone-driven pelvic disorder.
• Pain may arise from lesion–nerve–immune interactions, fibrosis, pelvic organ cross-sensitization, and central sensitization.
• Emerging targets include CGRP, IL-33/ST2, microglia, CX3CR1/P2X4R, sodium channels, mast cell–nerve signaling, anti-fibrotic pathways, and neuromodulation.
• Most of these pathways remain investigational, but they provide a roadmap for precision, non-hormonal treatment development.
• Expert excision surgery still matters—especially when it is integrated with neurofunctional, pain-informed, and multidisciplinary follow-up care.

Endometriosis Is Entering a New Scientific Era

For decades, endometriosis was framed primarily as a disease of misplaced endometrial-like tissue, retrograde menstruation, and estrogen-dependent lesion growth. Those concepts remain relevant—but they are no longer enough to explain the full patient experience. They do not fully account for why some patients have severe pain with relatively limited visible disease, why others continue to experience pain after technically successful surgery, or why bowel, bladder, musculoskeletal, neuropathic, and fatigue-related symptoms can coexist in the same person.

A growing body of translational research suggests that endometriosis behaves, in many patients, like a neuroimmune disease. In this model, lesions are only part of the story. Immune cells, nociceptors, mast cells, macrophages, peripheral nerves, spinal microglia, fibrosis, and the central nervous system all participate in the generation and persistence of pain.

This paradigm shift matters because it changes treatment strategy. Instead of asking only, “Where is the lesion?”, clinicians increasingly need to ask, “What biologic networks has the disease activated?” That question opens the door to targeted, non-hormonal, mechanism-based care.

 

Figure 1. ESSI infographic: The Neuroimmune Revolution in Endometriosis.

From a Traditional Model to a Neuroimmune Model

The traditional model of endometriosis is organ-centric: lesions or implants are assumed to explain symptoms directly, and treatment focuses on suppressing hormones or removing visible disease. That model has value, but it is incomplete.

The neuroimmune model is broader. It recognizes that lesions can drive inflammation, neuroangiogenesis, fibrosis, and altered signaling between the immune system and the nervous system. In this framework, pain is not just a local lesion phenomenon. It may reflect peripheral nociception, cross-organ sensitization, pelvic floor guarding, altered spinal processing, and central sensitization.

This does not diminish the importance of surgery. Rather, it places surgery within a more sophisticated therapeutic framework. Excision may remove a key disease driver, but the downstream neuroimmune consequences may still require dedicated management.

Figure 2. ESSI infographic: Traditional Model vs Neuroimmune Model.

From Lesion to Pain: The Neuroimmune Cascade

Several recent studies help illuminate how endometriosis pain may move from the pelvis to the nervous system. In a 2023 mouse model, Bashir and colleagues reported central nervous system-wide glial activation in association with endometriosis-related pain behaviors, supporting the concept that chronic endometriosis pain can involve central neuroinflammatory changes—not just pelvic pathology.

At the lesion level, immune–nerve crosstalk appears especially important. Sensory nerves may release neuropeptides such as CGRP, while macrophages and other immune cells help shape the inflammatory microenvironment. A 2025 preclinical study by Fattori and colleagues linked macrophage-derived IL-33 to pain and lesion formation, suggesting that nociceptor–macrophage communication may be a critical axis in disease persistence.

Fibrosis is another major component. Endometriosis is not merely inflammatory; it is also frequently fibrotic. Tissue stiffness, tethering, traction, and organ distortion can perpetuate pain mechanically while also contributing to ongoing immune activation and nerve irritation.

At the spinal level, microglial activation is increasingly implicated in chronic pelvic pain. Recent work examining CX3CR1/P2X4R signaling points to neuron–microglia communication as a plausible mechanism for pain amplification and central sensitization. Together, these findings support a model in which lesion biology, nerve signaling, and immune activation create self-reinforcing loops.

Figure 3. ESSI infographic: From Lesion to Pain—The Neuroimmune Cascade.

Emerging Treatment Pathways

The most exciting implication of the neuroimmune model is therapeutic. If endometriosis pain is driven by more than hormones alone, then treatment development can expand well beyond hormonal suppression and conventional analgesics.

Importantly, the pathways below are not all clinically established treatments for endometriosis today. Many remain preclinical, early translational, or repurposing opportunities. Still, they represent a meaningful roadmap for the future of mechanism-based care.

Figure 4. ESSI infographic: Emerging Treatment Pathways in Endometriosis.

Table 1. Mechanism-Based Treatment Roadmap

Pathway / Target	Why It Matters	Potential Clinical Clues	Translational Direction
CGRP pathway	CGRP links nociception, vasodilation, and neurogenic inflammation.	Migraine overlap, cyclical nerve-pain flares, sensory hypersensitivity.	Repurposing opportunity: CGRP antagonists (mAbs, gepants) in carefully phenotyped patients; investigational in endometriosis.
IL-33 / ST2	IL-33 appears to participate in lesion inflammation, macrophage signaling, and pain generation.	Highly inflammatory phenotype, fibrosis-rich lesions, severe pain.	Early translational target; pathway blockade remains investigational.
Microglial modulation	Microglia may sustain central sensitization and pain amplification.	Widespread pain, fatigue, sleep disturbance, cognitive fog, post-surgical persistent pain.	Preclinical/experimental focus on glial-modulating agents.
CX3CR1 / P2X4R	Neuron–microglia signaling may drive spinal pain amplification.	Neuropathic pelvic pain, allodynia, hyperalgesia.	Preclinical target within chronic pelvic pain research.
Voltage-gated sodium channels	Hyperexcitable nociceptors may contribute to shooting or electric pain.	Radiating pain, activity-triggered flares, nerve-territory symptoms.	Potential future role for selective nociceptor-targeted agents.
Mast cell–nerve interaction	Mast cells can sensitize nerves and amplify neuroinflammation.	Bladder/bowel reactivity, flushing, histamine-type symptoms, MCAS overlap.	Investigational use of mast-cell stabilizing or histamine-pathway strategies.
Anti-fibrotic strategies	Fibrosis contributes to stiffness, tethering, ischemia, and persistent pain.	Deep disease, traction pain, dyschezia, bladder tethering, frozen pelvis.	Long-term translational goal; may pair with expert excision surgery.
Neuromodulation	Pain circuits may need direct modulation when sensitization persists.	Refractory pain, autonomic dysfunction, bladder/bowel overlap, central sensitization.	Adjunctive pathway including SCS, DRG stimulation, PNS, or other neurofunctional approaches in selected cases.

1. CGRP-Pathway Therapies

CGRP is already clinically actionable in migraine medicine, making it one of the most intriguing translational pathways in endometriosis. Because CGRP participates in neurogenic inflammation and nociceptor signaling, it may be especially relevant in patients whose endometriosis pain has a strong sensory-neural phenotype. Although there is not yet an established role for CGRP antagonists in routine endometriosis care, this is a high-interest repurposing space.

2. IL-33 / Macrophage Signaling

IL-33 is emerging as a compelling immune target. Preclinical data suggest that macrophage-derived IL-33 may contribute both to lesion biology and to pain generation. This is exactly the type of lesion–immune–pain axis that future biomarker-driven trials should test.

3. Microglia and Central Sensitization

If microglial activation helps sustain pain at the spinal or central level, then the patient with persistent pain after surgery may not simply have ‘failed treatment’—they may have a centralized pain phenotype superimposed on pelvic disease. Recognizing that distinction is essential for personalized care.

4. Purinergic and Fractalkine Signaling

CX3CR1/P2X4R signaling highlights the importance of neuron–microglia communication. While highly experimental at present, it offers a mechanistic bridge between pelvic pathology and central pain amplification.

5. Sodium Channel Modulation

Voltage-gated sodium channels remain attractive targets whenever endometriosis pain behaves like neuropathic pain. This includes patients with burning, electric, radiating, or movement-triggered symptoms, especially in nerve-rich disease spaces.

6. Mast Cell–Nerve Biology

Mast cells may be particularly relevant in patients with endometriosis plus bladder pain syndrome, bowel reactivity, flushing, urticaria, or MCAS-like features. This is part of the broader Pelvic Overlap Spectrum that ESSI frequently emphasizes.

7. Anti-Fibrotic Strategies

Fibrosis deserves far more attention. In real-world disease, pain is often not just inflammatory but also mechanobiologic. Tissue stiffness, traction, and organ tethering may act as chronic pain drivers even when bleeding or cyclic inflammation is not the only culprit.

8. Neuromodulation and Pelvic Neurofunctional Care

Neuromodulation should be viewed as an adjunct—not a substitute—for good pathology control. In selected patients, however, it may play a valuable role in the management of refractory pain, bowel/bladder dysfunction, or autonomic dysregulation.

Why Surgery Still Matters

A neuroimmune model does not make surgery less important; it makes expert surgery more important. Deep infiltrating disease, endometriomas, ureteral disease, bowel involvement, diaphragm disease, fibrosis, and dense adhesive disease can all continue feeding nociceptive and inflammatory pathways if they are not adequately addressed.

The key conceptual shift is this: excision surgery removes or reduces a major biologic driver, but it may not reverse every downstream neural consequence immediately. For that reason, the best outcomes often come from integrated care—surgery plus pelvic floor rehabilitation, bowel/bladder support, pain-informed follow-up, and, when indicated, neurofunctional strategies.

What the Next Generation of Trials Should Look Like

The field does not merely need more treatment trials—it needs better phenotyping. The future of endometriosis therapeutics will depend on identifying which patients have inflammatory-dominant pain, neuropathic-dominant pain, fibrosis-dominant pain, mast-cell-associated pain, or centralized pain features.

This means proof-of-concept studies should incorporate mechanism-based endpoints whenever possible: lesion immunophenotyping, fibrosis assessment, sensory testing, validated pain phenotypes, and outcomes that extend beyond generic pain scores. In a disease this heterogeneous, precision phenotyping is not optional; it is foundational.

Commentary from the ESSI Doctors

Dr. Bagaria

“At ESSI, we often see patients whose symptoms cannot be explained by lesion location alone. The neuroimmune model helps explain why bowel pain, bladder pain, pelvic floor dysfunction, fatigue, and widespread pain can coexist. This is why careful phenotyping and multidisciplinary planning are so important.”

Dr. Fernandez

“A nerve-aware operation is different from simply burning visible spots. The surgical question is not only whether endometriosis is present, but whether the disease has created fibrosis, nerve irritation, organ tethering, or complex overlap pathology that continues to feed pain pathways.”

Dr. Cibulsky

“Patients with long-standing disease often present with overlapping pain generators. Excision is critical when pathology is present, but the postoperative plan must also consider pelvic floor recovery, bowel and bladder function, central sensitization, and the need for multimodal care.”

Conclusion

Endometriosis care is moving beyond a purely hormonal and anatomical framework. The emerging neuroimmune view does not replace surgery or deny the importance of lesions; instead, it contextualizes them inside a wider pain biology that includes immune activation, fibrosis, peripheral nerves, and central sensitization.

That shift is opening the door to new treatment pathways. Some—like CGRP repurposing—feel closer to translation. Others—like IL-33 pathway blockade or spinal microglial targeting—remain early but scientifically compelling. Together, they point toward a future of precision, non-hormonal, mechanism-based care integrated with expert excision surgery.

Selected References

1. Bashir ST, Redden CR, Raj K, et al. Endometriosis leads to central nervous system-wide glial activation in a mouse model of endometriosis. Journal of Neuroinflammation. 2023;20(1):59. PMID: 36879305. https://pubmed.ncbi.nlm.nih.gov/36879305/
2. Fattori V, Rasquel-Oliveira FS, Ochoa S, et al. Pro-endometriosis macrophage release of IL-33 is key for endometriosis pain and lesion formation. bioRxiv [preprint]. 2025. PMID: 41279884. https://pubmed.ncbi.nlm.nih.gov/41279884/
3. Wu Q, Yang F, Yang R, et al. CX3CR1/P2X4R signaling-mediated spinal microglial M1 polarization contributes to chronic pelvic pain in endometriosis. International Immunopharmacology. 2026;175:116471. PMID: 41791308. https://pubmed.ncbi.nlm.nih.gov/41791308/
4. Pergolizzi JV Jr, LeQuang JA, Taylor R, et al. Managing the neuroinflammatory pain of endometriosis in clinical practice. Expert Opinion on Pharmacotherapy. 2024. PMID: 39540855. https://pubmed.ncbi.nlm.nih.gov/39540855/
5. Machairiotis N, Vasilakaki S, Dryllis G, et al. Inflammatory Mediators and Pain in Endometriosis. Biomedicines. 2021;9(1):54. PMID: 33435569. https://pubmed.ncbi.nlm.nih.gov/33435569/
6. McKinnon BD, Bertschi D, Bersinger NA, Mueller MD. Inflammation and nerve fiber interaction in endometriotic pain. Trends in Endocrinology & Metabolism. 2015;26(1):1–10. PMID: 25465987. https://pubmed.ncbi.nlm.nih.gov/25465987/
7. Velho RV, Taube ET, Sezin T, et al. Neurogenic Inflammation in the Context of Endometriosis—What Do We Know? International Journal of Molecular Sciences. 2021;22(23):13102. https://pmc.ncbi.nlm.nih.gov/articles/PMC8658724/
8. Trapero C, Caorsi V, Mendez M, et al. Purinergic Signaling in Endometriosis-Associated Pain. International Journal of Molecular Sciences. 2020;21(21):8285. https://pmc.ncbi.nlm.nih.gov/articles/PMC7697899/
9. Chang L, Wang J, Chen Y, et al. Neuroendocrine–Immune Axis in Endometriosis: A Review on Treatment Implications. 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12650026/
10. Golińska M, Goy YS, Romero M, et al. Neuroinflammation is responsible for pain in endometriosis: targeting the JAK-STAT pathway and mast cell activation. Frontiers in Immunology. 2025. https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1621178/full
11. Abramiuk M, Grywalska E, Małecka-Massalska T, et al. The Role of the Immune System in the Development of Endometriosis. Cells. 2022;11(13):2028. https://pmc.ncbi.nlm.nih.gov/articles/PMC9265783/

 

Note: Several pathways discussed above are investigational or preclinical and should not be interpreted as established standard-of-care treatments for endometriosis at this time.