Investigation of liver-targeted peripheral focused ultrasound stimulation (pFUS) and its effect on glucose homeostasis and insulin resistance in type 2 diabetes mellitus: a proof of concept, phase 1 trial

BACKGROUND

Mechanical waves produced by ultrasound pulses have been shown to activate mechanosensitive ion channels and modulate peripheral nerves. However, while peripheral ultrasound neuromodulation has been demonstrated in vitro and in pre-clinical models, there have been few reports of clinical tests.

AIM

We modified a diagnostic imaging system for ultrasound neuromodulation in human subjects. We report the first safety and feasibility outcomes in subjects with type 2 diabetes (T2D) mellitus and discuss these outcomes in relation to previous pre-clinical results.

DESIGN

The study was performed as an open label feasibility study to assess the effects of hepatic ultrasound (targeted to the porta hepatis) on glucometabolic parameters in subjects with T2D. Stimulation (peripheral focused ultrasound stimulation treatment) was performed for 3 days (i.e. 15 min per day), preceded by a baseline examination and followed by a 2-week observation period.

METHODS

Multiple metabolic assays were employed including measures of fasting glucose and insulin, insulin resistance and glucose metabolism. The safety and tolerability were also assessed by monitoring adverse events, changes in vital signs, electrocardiogram parameters and clinical laboratory measures.

RESULTS AND CONCLUSION

We report post-pFUS trends in several outcomes that were consistent with previous pre-clinical findings. Fasting insulin was lowered, resulting in a reduction of HOMA-IR scores (P-value 0.01; corrected Wilcoxon signed-rank test). Additional safety and exploratory markers demonstrated no device-related adverse impact of pFUS. Our findings demonstrate that pFUS represents a promising new treatment modality that could be used as a non-pharmaceutical adjunct or even alternative to current drug treatments in diabetes.

Focused ultrasound neuromodulation of the spleen activates an anti-inflammatory response in humans

Focused ultrasound stimulation (FUS) activates mechanosensitive ion channels and is emerging as a method of noninvasive neuromodulation. In preclinical studies, FUS of the spleen (sFUS) activates an anti-inflammatory neural pathway which suppresses acute and chronic inflammation. However, the relevance of sFUS for regulating inflammatory responses in humans is unknown. Here, we used a modified diagnostic ultrasound imaging system to target the spleen of healthy human subjects with 3 min of continuously swept or stationary focused pulsed ultrasound, delivered at three different energy levels within allowable safety exposure limits. Potential anti-inflammatory effects of sFUS were assessed by measuring sFUS-elicited changes in endotoxin-induced tumor necrosis factor (TNF) production in whole blood samples from insonified subjects. We found that stimulation with either continuously swept or focused pulsed ultrasound has an anti-inflammatory effect: sFUS lowers TNF production for >2 h, with TNF returning to baseline by 24 h following sFUS. This response is independent of anatomical target (i.e., spleen hilum or parenchyma) or ultrasound energy level. No clinical, biochemical, or hematological parameters are adversely impacted. This is the first demonstration that sFUS suppresses the normal inflammatory response in humans, with potential implications for noninvasive bioelectronic therapy of inflammatory disorders.

First-in-human imaging using a MR-compatible e4D ultrasound probe for motion management of radiotherapy

PURPOSE

Respiration-induced tumor or organ positional changes can impact the accuracy of external beam radiotherapy. Motion management strategies are used to account for these changes during treatment. The authors report on the development, testing, and first-in-human evaluation of an electronic 4D (e4D) MR-compatible ultrasound probe that was designed for hands-free operation in a MR and linear accelerator (LINAC) environment.

METHODS

Ultrasound components were evaluated for MR compatibility. Electromagnetic interference (EMI) shielding was used to enclose the entire probe and a factory-fabricated cable shielded with copper braids was integrated into the probe. A series of simultaneous ultrasound and MR scans were acquired and analyzed in five healthy volunteers.

RESULTS

The ultrasound probe led to minor susceptibility artifacts in the MR images immediately proximal to the ultrasound probe at a depth of <10 mm. Ultrasound and MR-based motion traces that were derived by tracking the salient motion of endogenous target structures in the superior-inferior (SI) direction demonstrated good concordance (Pearson correlation coefficients of 0.95-0.98) between the ultrasound and MRI datasets.

CONCLUSION

We have demonstrated that our hands-free, e4D probe can acquire ultrasound images during a MR acquisition at frame rates of approximately 4 frames per second (fps) without impacting either the MR or ultrasound image quality. This use of this technology for interventional procedures (e.g. biopsies and drug delivery) and motion compensation during imaging are also being explored.

A Magnetic Resonance Compatible E4D Ultrasound Probe for Motion Management of Radiation Therapy

We developed a magnetic resonance compatible real-time, three-dimensional imaging ultrasound probe for motion management of radiation therapy for liver cancer. The probe contains an 18,000-element, 46.8 mm × 21.5 mm matrix array constructed from three tiled transducer modules with integrated beamforming ASICs. The center frequency and -6 dB fractional bandwidth of the probe was 3.6 MHz and 85 percent respectively. Ferromagnetic materials in the acoustic stack, flex interconnect and electronics boards were greatly minimized for magnetic resonance compatibility. The probe and cable were shielded to minimize the impact of radiofrequency noise on both the ultrasound and magnetic resonance images. The probe's low-profile, side-viewing design allows it to be strapped to a patient so that images may be acquired hands-free. We present simultaneously acquired ultrasound and 3 Tesla magnetic resonance images with minimal artifacts in both images.

Microfluidic Tissue Mesodissection in Molecular Cancer Diagnostics

We present a mesodissection platform that retains the advantages of laser-based dissection instrumentation with the speed and ease of manual dissection. Tissue dissection in clinical laboratories is often performed by manually scraping a physician-selected region from standard glass slide mounts. In this manner, costs associated with dissection remain low, but spatial resolution is compromised. In contrast, laser microdissection methods maintain spatial resolution that matches the requirements for analysis of important tissue heterogeneity but remains costly and labor intensive. We demonstrate a microfluidic tool for rapid extraction of histological regions of interest from formalin-fixed paraffin-embedded tissue, which uses a simple and automated method that is compatible with most downstream enzymatic reactions, including protocols used for next-generation DNA sequencing.

Comparison of impedance measurements near the skin of newborns and adults

Electrical impedance tomography (EIT) is a non-invasive imaging technology that has been extensively studied for monitoring lung function of neonatal and adult subjects, especially in neonatal intensive care unit (NICU) and intensive care unit (ICU) environments. The sources of the total impedance in these applications include internal organs, near-boundary tissues, electrode-skin impedance, electrodes and conducting wires. This total impedance must be considered for system design and setting voltage gain since it will contribute to the measured voltage. To adapt a single instrument for use on infants and adults, we studied the difference between the impedance near the skin in both classes of patients. We used a simultaneous multi-source EIT (SMS-EIT) system to make impedance measurements. Characteristic resistance was calculated for two different current patterns: one that is more sensitive to boundary region impedance and another that is more sensitive to interior changes. We present ratios of these resistances to assess the relative contribution of near-skin effects to the overall impedance. Twenty adult ICU subjects (10 male, 10 female, age: 49.05  ±  16.32 years (mean  ±  standard deviation)) and 45 neonates (23 male, 22 female, gestational age: 37.67  ±  2.11 weeks, postnatal age, 2.56  ±  2.67 d) were studied at Columbia University Medical Center. Impedance measurements at 10 kHz were collected for approximately one hour from each subject. The characteristic resistance ratio for each subject was computed and analyzed. The result shows the impedance at or near the skin of newborns is significantly higher than in adult subjects.

Real-time 3D electrical impedance imaging for ventilation and perfusion of the lung in lateral decubitus position

We report a prototype Electrical Impedance Imaging System. It is able to detect the gravity-induced changes in the distributions of perfusion and ventilation in the lung between supine and lateral decubitus positions. Impedance data were collected on healthy volunteer subjects and 3D reconstructed images were produced in real-time, 20 frames per second on site, without using averaging or a contrast agent. Imaging data also can be reconstructed offline for further analysis.

Real-time 3D electrical impedance imaging for ventilation monitoring of the lung: Pilot study

We report an Electrical Impedance Tomography device capable of detecting gravity-induced regional ventilation changes in real-time without averaging or using a contrast medium. Changes in lung ventilation are demonstrated in right and left lateral decubitus position and compared to those seen in an upright and supine normal subject.