Ultrasound-guided Histotripsy for the Complete and Rapid Ablation of Uterine Fibroids

2026-03-20

Uterine fibroids (leiomyomas) are the most common benign tumors in women of reproductive age. The overarching goal of this project was to test the technical feasibility and in vivo efficacy of ultrasound-guided histotripsy for the treatment of uterine fibroids. First, experiments were completed using red blood cell tissue phantoms to compare ablation efficiency at PRFs up to 2.5kHz, with results showing effective ablation at all PRFs. Experiments were then conducted to evaluate our recently developed ultra-high PRF histotripsy pulsing regimes for complete and efficient uterine fibroid disintegration using ex vivo human uterine fibroid samples. Histological analysis from these studies showed effective fibroid ablation with histotripsy at all tested PRFs, with varying degrees of tissue damage observed under different PRF and dose combinations. These studies have established that histotripsy can effectively ablate fibroid tissues with an approximate 10x increase in treatment efficiency compared to our previous pilot studies, opening the door for histotripsy as a clinically relevant non-invasive treatment option for fibroids. A manuscript outlining these results is currently in review with Ultrasound in Medicine and Biology. In the second part of this study, our goal was to test the in vivo safety and efficacy of histotripsy in a rat leiomyoma model. Due to the lack of established animal models for uterine fibroids, our group proposed to develop and test a rodent uterine fibroid model based on the only hormone model we could identify in the literature. Following this 9-month protocol, we unfortunately did not observe fibroid formation in any of the rats, although swelling was present in the uterus, cervix, and ovaries, indicating a potential hormone-induced phenotype. Overall, results suggest that histotripsy has potential as a non-invasive and non-thermal treatment for uterine fibroids with future studies needed in order to study the safety and long-term efficacy of histotripsy fibroid ablation which could not be assessed here due to the lack of fibroid formation in the rodent model.

Turning Up the Heat: Using Focused Ultrasound to Shift the Immunosuppressive Breast Cancer Tumor Microenvironment from “Cold” to “Hot”, Augmenting Systemic Anti-Tumor Immune Activation

2026-02-20

The overarching goal of this research is to investigate the immunological response of breast tumors to focused ultrasound ablation of breast cancer in an in vivo 4T1 murine model. More specifically, this work is evaluating the hypothesis that histotripsy may result in a more robust immune activation locally and systemically compared to thermal ablation. Our overarching hypothesis predicts the cell death and tumor ablation driven by histotripsy activates the innate immune system and promotes a shift in the tumor microenvironment from immunosuppressive (“cold”) to pro-inflammatory (“hot”), which serves to recruit increased numbers of antigen presenting cells to the local tumor. Work on this project has been completed for all experiments as well as additional experiments discussed as part of our NCE (repeating histotripsy experiments to further evaluate initial findings of immune responses). The results highlighted in the sections below outline the data collected in our original studies, discussions around the challenges that were faced over the course of the project, and our more results from our more recent experiments since the NCE. We have also added results from additional parameter studies that we have conducted in the time since the last report. Overall findings show that histotripsy was capable of generating bubble clouds and ablation of the 4T1 breast tumors, but no significant reductions in tumor burden were noted for survival studies. Overall, these findings, coupled with results from our other preclinical studies in different tumor models, suggest that further work is necessary in order to understand the effects of histotripsy and HIFU pulsing on immune-stimulation in the treatment of breast cancer. Furthermore, results clearly illustrate the need for dedicated efforts to optimize histotripsy parameters and dosing for specific tumor types in order to enable optimal ablative and immune-stimulation outcomes.

The PTP4A3 inhibitor KVX-053 reduces Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virulence, inflammation, and development of acute lung injury in K18-hACE2 mice

Respiratory Research · 2025-10-28 · 1 citations

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused a global health crisis, marked by high transmissibility and virulence. Despite widespread vaccination efforts, effective treatments for COVID-19, particularly for severe cases leading to Acute Respiratory Distress Syndrome (ARDS), remain limited. This study investigates the efficacy of KVX-053, a protein tyrosine phosphatase type IVA (PTP4A3) small molecule inhibitor, in modulating SARS-CoV-2-induced inflammation and lung injury using in vitro cell models and in vivo K18-hACE2 transgenic mice. KVX-053 reduced in vitro pro-inflammatory cytokine expression, including TNFα, CXCL10, and CXCL11, without impacting viral replication or cell viability. K18-hACE2 mice treated with KVX-053 demonstrated marked improvement in clinical scores and reduced histological evidence of lung injury compared to untreated SARS-CoV-2-infected controls. KVX-053 mitigated the activation of key inflammatory mediators in the lung, including NLRP3 inflammasomes, IL-6, and phosphorylated STAT3, effectively curbing the "cytokine storm" associated with severe COVID-19. Importantly, treatment preserved lung parenchymal integrity, reduced edema, and minimized macrophage infiltration. Our findings highlight PTP4A3 as a potential critical regulator of the inflammatory response during SARS-CoV-2 infection. KVX-053, a potent and selective PTP4A3 inhibitor, emerges as a promising host-directed therapeutic strategy for mitigating ARDS and inflammation-driven lung injury in SARS-CoV-2 and potentially other respiratory viral infections. Future studies are required to optimize dosing strategies, elucidate precise molecular mechanisms, and validate these findings in clinical settings.

Mystery machine: the complex roles of NLRX1 in viral infection

Frontiers in Immunology · 2025-04-28 · 1 citations

Effective antiviral immunity requires a delicate balance between controlling infection and preventing excessive inflammation. NLRX1, an atypical member of the NOD-like receptor family, plays a crucial regulatory role in this process by modulating immune responses to both RNA and DNA viruses. Unlike other NLRs, NLRX1 does not directly activate inflammatory pathways, but rather fine tunes immune responses through interactions with key signaling initiators like MAVS, FAF1, viral RNA, and FBXO6. These interactions allow NLRX1 to influence antiviral pathways in a highly context-dependent manner. In RNA virus infections, NLRX1 can either enhance immune signaling to restrict viral replication or suppress type 1 IFN responses to promote viral persistence. Similarly, in DNA viral infections, NLRX1 exerts either protective or pathogenic effects, though the precise mechanisms remain unclear. Emerging evidence suggests that NLRX1 may also serve as a key regulator of inflammation and metabolic processes during infection, further contributing to its complex role in immunity. By synthesizing current research, this review provides insight into how NLRX1 regulates immune signaling in RNA and DNA viral infections, highlighting its dynamic role in antiviral immunity and the remaining gaps in our understanding.

Non-Invasive Pancreas Ablation Using Histotripsy: Pre-clinical Safety Study in an In Vivo Porcine Model

Ultrasound in Medicine & Biology · 2025-10-03 · 2 citations

Transient Lymphatic Remodeling Follows Sub-Ablative High-Frequency Irreversible Electroporation Therapy in a 4T1 Murine Model

Annals of Biomedical Engineering · 2025-02-25 · 6 citations

High-frequency irreversible electroporation (H-FIRE) is a minimally invasive local ablation therapy known to activate the adaptive immune system and reprogram the tumor microenvironment. Its predecessor, irreversible electroporation (IRE), transiently increases microvascular density and immune cell infiltration within the surviving non-ablated and non-necrotic tumor region, also known as the viable tumor region. However, the impact of pulse electric field therapies on lymphatic vessels, crucial for T-cell fate and maturation, remains unclear. This study investigates how sub-ablative H-FIRE (SA-HFIRE) affects lymphatic and blood microvascular remodeling in the 4T1 mammary mouse model. We conducted a temporal and spatial analysis to evaluate vascular changes in the viable tumor, peritumoral fat pad, and tumor-draining lymph node post-treatment. Histological examination showed a transient increase in blood vessel density on Day 1 post-treatment, followed by a spike in lymphatic vessel density in the viable tumor region on Day 3 post-treatment, increased lymphatic vessel density in the peripheral fat pad, and minimal remodeling of the tumor-draining lymph node within 3 days following treatment. Gene expression analysis indicated elevated levels of CCL21 and CXCL2 on Day 1 post-treatment, while VEGFA and VEGFC did not appear to contribute to vascular remodeling. Likewise, CCL21 protein content in tumor-draining axillary lymph nodes correlated with gene expression data from the viable tumor region. These findings suggest a dynamic shift in lymphatic and blood microvascular structures post-SA-HFIRE, potentially enhancing the adaptive immune response through CCL21-mediated lymphatic homing and subsequent lymph node microvascular remodeling. Future work will assess the immune and transport function of the microvasculature to inform experiments aimed at the application of adjuvant therapies during scenarios of tumor partial ablation.

NF-κB-inducing kinase (NIK): an emerging therapeutic target in human disease

Expert Opinion on Therapeutic Targets · 2025-02-01 · 3 citations

Innate Immunity Never “NODs” Off: NLRs Regulate the Host Anti‐Viral Immune Response

Immunological Reviews · 2025-01-29 · 8 citations

A robust innate immune response is essential in combating viral pathogens. However, it is equally critical to quell overzealous immune signaling to limit collateral damage and enable inflammation resolution. Pattern recognition receptors are critical regulators of these processes. The cytosolic nucleotide-binding domain leucine-rich repeat (NLR; NOD-like receptor) family of pattern recognition receptors plays essential roles in the sensing of viral pathogen-associated molecular patterns and is best characterized for itsr pro-inflammatory biological functions. Specifically, these include the formation of multi-protein complexes, defined as inflammasomes or NODosomes that regulate the production of IL-1beta, IL-18, and pyroptosis, or the induction of NF-ΚB signaling. While these biological effects are inherently pro-inflammatory, it is also important to recognize that other NLR family members conversely function to negatively regulate inflammation through modulating signaling initiated by other families of pattern recognition receptors. Mechanistically, these unique NLRs also form multiprotein complexes that act to attenuate a variety of biological signaling pathways, such as the inhibition of NF-ΚB. This inhibition facilitates inflammation resolution and functions to restore cellular homeostasis. Despite extensive characterization of individual NLR family members, the mechanisms of immune system regulation are highly nuanced and remain enigmatic. This is especially true for non-inflammasome-forming, regulatory NLRs. Here, we discuss recent findings associated with NLR family members that play essential roles in the host immune response to viruses and mechanisms by which these pattern recognition receptors may function to regulate antiviral immunity.

Fighting Covid-19 with NLRX1 9340

The Journal of Immunology · 2025-11-01

Abstract Description While many patients only experience flu like symptoms after contracting SARS-CoV-2, a small subset of patients will go on to develop acute respiratory distress syndrome (ARDS). ARDS is characterized by an overzealous inflammatory response brought on by downstream signaling of pattern recognition receptors. One such receptor, NLRX1, is shown to negatively regulate downstream inflammatory signaling during viral infections. However, its actions can be dichotomous depending on cellular context. ssRNA can be sensed by the C-terminal of NLRX1 implicating it in the host response of ssRNA viruses, such as SARS-CoV-2. The exact role of NLRX1 during SARS-CoV-2 infection remains unclear. We show NLRX1 to be protective in SARS-CoV-2 pathology. snRNA data taken from COVID-19 positive lung autopsy samples showed a down regulation of NLRX1 in airway epithelial cells while pathways modulated by NLRX1 were shown to be deferentially enriched. Nlrx1-/- mice infected with the mouse adapted SARS-CoV-2 virus had a greater viral titer and airway inflammation, including increased cellular denuding at 2 days post infection compared to wild-type animals. Furthermore, human airway epithelial cells over-expressing NLRX1, not only had decreased viral replication but may be protecting against a viral shift of host metabolism to limit viral replication. Our results suggest NLRX1 antagonizes SARS-CoV-2 through multiple pathways. With more research, NLRX1 could be a promising drug target for Covid-19. Topic Categories Viral Immunology (VIR)

Abstract 3466: Bubble therapy: Histotripsy ablation of pancreatic tumors in an <i>in vivo</i> murine model affects the tumor microenvironment and increases systemic anti-tumor immunity

Cancer Research · 2025-04-21

Abstract Pancreatic cancer is one of the leading causes of cancer-related deaths, highlighting the urgent need for innovative treatment strategies. Histotripsy is a non-invasive, non-ionizing, non-thermal, image-guided focused ultrasound ablation treatment method that uses high-pressure pulses to create acoustic cavitation, a “bubble cloud, ” at the target. The rapid expansion and collapse of this bubble cloud ablates the tumor into an acellular homogenate. In this study, we evaluated the hypothesis that histotripsy ablation of pancreatic tumors reduces tumor burden, activates systemic immune responses, and induces an abscopal-like effect. Our in-vivo study is a contralateral study conducted in C57BL/6J mice, employing a specialized histotripsy setup designed for precision. This setup featured a customized 1 MHz, 8-element histotripsy transducer engineered with a tailored focal point geometry. We targeted partial ablation around 50-60% to activate the immune responses and convert the “cold” pancreatic tumor microenvironment to “hot” tumor microenvironment. Treatment parameters included a peak negative pressure (PNP) of 250 Hz, a pulse repetition frequency (PRF) of 250 Hz, and 250 pulses per focal point. Mice were harvested in 5 groups/timepoints (2 hours, 24 hours, 7 days, 14 days and 21 days), with biological assessments generally focused on ablation zone, structural effects of histotripsy, chemokines and cytokines released and immune cell populations. The study’s significance lies in understanding how histotripsy influences immune responses, particularly T cell infiltration and proliferation, from the treated tumor site to the untreated contralateral tumor site. Our data demonstrated that histotripsy effectively reduced tumor volume, with significant reductions in tumor diameter observed in both treated and contralateral untreated tumors compared to control groups. Flow cytometry analysis revealed significant changes in immune cell populations across treated and control groups. Transcriptomic analyses identified differentially expressed genes and pathways associated with systemic anti-tumor immune responses, while mass spectrometry highlighted antigens presented by antigen-presenting cells. Overall, the results indicated that histotripsy promotes a localized immune response, leading to immune system activation and substantial alterations in the tumor microenvironment. These systemic immunological changes present potential targets for adjuvant therapies, underscoring the promise of histotripsy as a therapeutic modality in pancreatic cancer treatment. Citation Format: Tamalika Paul, Victor Lopez, Cora Youngs, Carley Elliott, K.M Imran, Tyler Moore, Manali Powar, Benjamin Tintera, Eli Vlaisavljevich, Irving Coy Allen. Bubble therapy: Histotripsy ablation of pancreatic tumors in an in vivo murine model affects the tumor microenvironment and increases systemic anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3466.