The role of vagus nerve stimulation in sepsis

Sepsis is a life-threatening organ dysfunction due to a dysregulated host response to infection. The infection triggers a host response with an early hyperinflammatory and subsequent anti-inflammatory phase, both regulated by homeostatic mechanisms. A breakdown of these regulatory mechanisms can result in an exaggerated immune response which leads to complications. The vagus nerve plays a central role in regulating inflammation and the balance between the sympathetic and parasympathetic arms of the autonomic nervous system through the “cholinergic anti-inflammatory pathway”. Several experimental models support the notion that external stimulation of the vagus nerve can modulate inflammation and restore the sympatho-vagal balance which may translate to improved outcomes in sepsis. Here, we review the pathophysiologic basis and evidence behind vagus nerve stimulation in sepsis.

Current perspectives on the safe electrical stimulation of peripheral nerves with platinum electrodes

This review details some peripheral nervous system (PNS) targets and electrode designs used for electrical stimulation. It investigates limitations in current knowledge of safe electrical stimulation and possible future electrode developments. Current PNS targets are large, leading to poor resolution and off-target side-effects. Most clinical devices are platinum or platinum/iridium embedded in an insulation material. Their safety is usually guided by the Shannon plot, which is not valid for the PNS. New electrode designs are needed to target smaller nerve fibers, enabling higher resolution electrical therapies with fewer off-target side-effects. Damage can occur through biological and electrochemical mechanisms. Greater mechanistic understanding is required to ensure safe and efficacious, long-term electrical stimulation with new electrode materials, geometries and stimulation waveforms.

Designing a bioelectronic treatment for Type 1 diabetes: targeted parasympathetic modulation of insulin secretion

The pancreas is a visceral organ with exocrine functions for digestion and endocrine functions for maintenance of blood glucose homeostasis. In pancreatic diseases such as Type 1 diabetes, islets of the endocrine pancreas become dysfunctional and normal regulation of blood glucose concentration ceases. In healthy individuals, parasympathetic signaling to islets via the vagus nerve, triggers release of insulin from pancreatic β-cells and glucagon from α-cells. Using electrical stimulation to augment parasympathetic signaling may provide a way to control pancreatic endocrine functions and ultimately control blood glucose. Historical data suggest that cervical vagus nerve stimulation recruits many visceral organ systems. Simultaneous modulation of liver and digestive function along with pancreatic function provides differential signals that work to both raise and lower blood glucose. Targeted pancreatic vagus nerve stimulation may provide a solution to minimizing off-target effects through careful electrode placement just prior to pancreatic insertion.

Transcutaneous auricular vagus nerve stimulation for the treatment of irritable bowel syndrome: a pilot, open-label study

Aim: Irritable bowel syndrome (IBS) is a frequent disease, associating chronic abdominal pain and abnormal bowel habits. The sympatho-vagal balance may be altered in IBS. We tested the effect of transcutaneous auricular stimulation of the left vagus nerve (taVNS) on symptoms and physiological and biological variables. Patients & methods: Twelve IBS women agreed to apply taVNS for 6 months. Evaluation was based on feasibility, symptoms, psychological questionnaires, fecal caprotectin, blood cytokines and bowel transit times. Results: Nine patients completed the trial: there was a significant improvement of symptoms at 3 and 6 months although none of the measured variables were modified by taVNS. Conclusion: The results suggest taVNS is feasible and may improve IBS symptoms. Randomized controlled studies are needed to confirm these preliminary results. ClinicalTrials.gov : NCT02420158.

Advances in bioelectronic medicine: noninvasive electrical, ultrasound and magnetic nerve stimulation

The mammalian nervous system has evolved over millions of years to protect the host. Harnessing neural pathways for therapeutic purposes is postulated to enhance treatment specificity and minimize adverse reactions. Bioelectronic medicine aims to diagnose and treat diseases through devices that regulate electrical signaling within the nervous system. Traditionally, this was accomplished via surgical implantation of electrical pulse generators directly onto peripheral nerves. While efficacious, this approach has significant limitations, including complications and associated costs of surgical procedures, and practical issues with treating acute onset and/or short-lived diseases with invasive approaches. Novel stimulation paradigms are currently under development to overcome these clinical challenges and ultimately expand the therapeutic potential of bioelectronic medicine. Here we review noninvasive electrical, ultrasound and magnetic nerve stimulation strategies in the context of more invasive electrical therapies, and discuss their potential impact on the field of bioelectronic medicine.

Utilizing prosthetic technology to improve quality of life: an interview with Ranu Jung and James Abbas

In this interview, we spoke with Ranu and James at SfN Neuroscience (19–23 October 2019, Chicago, IL, USA) to discover more about their collaboration on a clinical trial aiming to improve the lives of American veterans and service members who have lost limbs. The clinical trial involves the adaptive neural systems neural-enabled prosthetic hand system [ 1 , 2 ].

System and methodology to study and stimulate gastric electrical activity in small freely behaving animals

Aim: To develop and validate a system that can wirelessly acquire gastric slow waves and deliver electrical pulses to the stomach. Materials & methods: The system is composed of a front-end and a back-end unit connected to a computer, which runs a custom-made graphical user interface. The system was validated on benchtop and in vivo studies. Results: Benchtop validation showed an appropriate frequency response to acquire slow waves. Moreover, the system was able to deliver electrical pulses at amplitudes up to ±10 mA. Slow wave activity recorded from the stomach of rats was in the range of approximately five cycles per minute (cpm). Pulses delivered to the stomach of a rat every 15 s and reduced the activity to 4 cpm during the stimulation period. Conclusion: This study reports the first wireless system and methodology that can be used to acquire slow waves and deliver electrical stimulation to the stomach of small freely behaving animals.