A Dual-Mode Multifunctional Pulsed Radio-Frequency Stimulator for Trigeminal Neuralgia Relief and its Animal Model

Transient Receptor Potential Channels: Multiple Modulators of Peripheral Neuropathic Pain in Several Rodent Models

Neuropathic pain, a prevalent chronic condition in clinical settings, has attracted widespread societal attention. This condition is characterized by a persistent pain state accompanied by affective and cognitive disruptions, significantly impacting patients' quality of life. However, current clinical therapies fall short of addressing its complexity. Thus, exploring the underlying molecular mechanism of neuropathic pain and identifying potential targets for intervention is highly warranted. The transient receptor potential (TRP) receptors, a class of widely distributed channel proteins, in the nervous system, play a crucial role in sensory signaling, cellular calcium regulation, and developmental influences. TRP ion channels are also responsible for various sensory responses including heat, cold, pain, and stress. This review highlights recent advances in understanding TRPs in various rodent models of neuropathic pain, aiming to uncover potential therapeutic targets for clinical management.

Wireless Stimulation of Motor Cortex Through a Collagen Dura Substitute Using an Ultra-Thin Implant Fabricated on Parylene/PDMS

We present the design, fabrication, and in vivo testing of an ultra-thin (100 μm) wireless and battery-free implant for stimulation of the brain's cortex. The implant is fabricated on a flexible and transparent parylene/PDMS substrate, and it is miniaturized to dimensions of 15.6 × 6.6 mm 2. The frequency and pulse width of the monophasic voltage pulses are determined through On-Off keying (OOK) modulation of a wireless transmission at 2.45 GHz. Furthermore, the implant triggered a motor response in vivo when tested in 6 rodents. Limb response was observed by wireless stimulation of the brain's motor cortex through an FDA-approved collagen dura substitute that was placed on the dura in the craniotomy site, with no direct contact between the implant's electrodes and the brain's cortical surface. Therefore, the wireless stimulation method reported herein enables the concept of an e-dura substitute, where wireless electronics can be integrated onto a conventional dura substitute to augment its therapeutic function and administer any desired stimulation protocol without the need for post-surgical intervention for battery replacement or reprogramming stimulation parameters.

Progress in animal models of trigeminal neuralgia

OBJECTIVE

This review aims to systematically summarize the methods of establishing various models of trigeminal neuralgia (TN), the scope of application, and current animals used in TN research and the corresponding pain measurements, hoping to provide valuable reference for researchers to select appropriate TN animal models and make contributions to the research of pathophysiology and management of the disease.

DESIGN

The related literatures of TN were searched through PubMed database using different combinations of the following terms and keywords including but not limited: animal models, trigeminal neuralgia, orofacial neuropathic pain. To find the maximum number of eligible articles, no filters were used in the search. The references of eligible studies were analyzed and reviewed comprehensively.

RESULTS

This study summarized the current animal models of TN, categorized them into the following groups: chemical induction, photochemical induction, surgery and genetic engineering, and introduced various measurement methods to evaluate animal pain behaviors.

CONCLUSIONS

Although a variety of methods are used to establish disease models, there is no ideal TN model that can reflect all the characteristics of the disease. Therefore, there is still a need to develop more novel animal models in order to further study the etiology, pathological mechanism and potential treatment of TN.

Efficacy and safety of pulsed radiofrequency combined with pregabalin for herpetic neuralgia: A systematic review and meta-analysis

BACKGROUND

Pulsed radiofrequency (PRF), as a new technique, is used to treat a variety of chronic pain syndromes, but it has a high recurrence rate for herpetic neuralgia and is often combined with drugs therapy. The aim of this study was to comprehensively evaluate the efficacy and safety of PRF combined with pregabalin in the treatment of herpetic neuralgia.

METHODS

The electronic databases, including CNKI, Wanfang data, PubMed, Embase, web of science, and Cochrane Library were searched from inception to January 31, 2023. The outcomes were pain scores, sleep quality and side effects.

RESULTS

Fifteen studies with 1817 patients were included in this meta-analysis. PRF combined with pregabalin significantly reduced the visual analogue scale/score in patients with postherpetic neuralgia or herpes zoster neuralgia when compared with pregabalin or PRF monotherapy [P < .00001, standardized mean difference (SMD) = -2.01, confidence intervals (CI) = -2.36 to -1.66; P < .00001, SMD = -0.69, CI = -0.77 to -0.61]. Compared with pregabalin monotherapy, PRF combined with pregabalin significantly decreased the pittsburgh sleep quality index score, the dosage and number of days of using pregabalin (P < .00001, SMD = -1.68, CI = -2.19 to -1.17; P < .00001, SMD = -0.94, CI = -1.25 to -0.64; P < .00001, SMD = -1.52, CI = -1.85 to -1.19). However, there was no significant difference in the effect of PRF combined with pregabalin versus PRF alone on pittsburgh sleep quality index score in patients with postherpetic neuralgia (P = .70, SMD = -1.02, CI = -6.11 to 4.07). In addition, PRF combined with pregabalin could significantly decrease the incidence of dizziness, somnolence, ataxia and pain at puncture site when compared with pregabalin monotherapy (P = .0007, odds ratio [OR] = 0.56, CI = 0.40 to 0.78; P = .008, OR = 0.60, CI = 0.41 to 0.88; P = .008, OR = 0.52, CI = 0.32 to 0.84; P = .0007, OR = 12.39, CI = 2.87 to 53.43), but no significant difference was observed when compared with PRF alone.

CONCLUSIONS

PRF combined with pregabalin can effectively alleviate the pain intensity and improve sleep quality in patients with herpetic neuralgia, and the incidence of complications was low, so it was worthy of clinical application.

Passive and Flexible Wireless Electronics Fabricated on Parylene/PDMS Substrate for Stimulation of Human Stem Cell-Derived Cardiomyocytes

In this paper, we report the development of a wireless, passive, biocompatible, and flexible system for stimulation of human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMS). Fabricated on a transparent parylene/PDMS substrate, the proposed stimulator enables real-time excitation and characterization of hiPSC-CMs cultured on-board. The device comprises a rectenna operating at 2.35 GHz which receives radio frequency (RF) energy from an external transmitter and converts it into DC voltage to deliver monophasic stimulation. The operation of the stimulator was primarily verified by delivering monophasic voltage pulses through gold electrodes to hiPSC-CMs cultured on the Matrigel-coated substrates. Stimulated hiPSC-CMs beat in accordance with the monophasic pulses when delivered at 0.5, 1, and 2 Hz pulsing frequency, while no significant cell death was observed. The wireless stimulator could generate monophasic pulses with an amplitude of 8 V at a distance of 15 mm. These results demonstrated the proposed wireless stimulator's efficacy for providing electrical stimulation to engineered cardiac tissues. The proposed stimulator will have a wide application in tissue engineering where a fully wireless stimulation of electroconductive cells is needed. The device also has potential to be employed as a cardiac stimulator by delivering external stimulation and regulating the contractions of cardiac tissue.