Specific Electrical Stimulation Research Articles

Silver electroceutical technology to treat sarcopenia

While the world is rapidly transforming into a superaging society, pharmaceutical approaches to treat sarcopenia have hitherto not been successful due to their insufficient efficacy and failure to specifically target skeletal muscle cells (skMCs). Although electrical stimulation (ES) is emerging as an alternative intervention, its efficacy toward treating sarcopenia remains unexplored. In this study, we demonstrate a silver electroceutical technology with the potential to treat sarcopenia. First, we developed a high-throughput ES screening platform that can simultaneously stimulate 15 independent conditions, while utilizing only a small number of human-derived primary aged/young skMCs (hAskMC/hYskMC). The in vitro screening showed that specific ES conditions induced hypertrophy and rejuvenation in hAskMCs, and the optimal ES frequency in hAskMCs was different from that in hYskMCs. When applied to aged mice in vivo, specific ES conditions improved the prevalence and thickness of Type IIA fibers, along with biomechanical attributes, toward a younger skMC phenotype. This study is expected to pave the way toward an electroceutical treatment for sarcopenia with minimal side effects and help realize personalized bioelectronic medicine.

Expert Recommendations for a Clinical Guide Supporting the Use of Electrical Stimulation in Occupational Therapy Treatment of Spinal Cord Injury.

Clinical application of electrical stimulation (ES) to address functional deficits for those with spinal cord injury (SCI) is not consistent among occupational therapy practitioners, likely because of limited occupational therapy-specific clinical guidelines (OT-CG). Clinicians report the need for evidence-based guidance that supports their practice. To identify occupational therapy practitioners' needs to support ES application in treatment sessions, utility of existing clinical practice guidelines for occupational therapy practitioners, challenges and opportunities to translate research findings into clinical practice, and desirable characteristics for an occupational therapy-specific ES clinical guide. A panel of 7 senior occupational therapy clinicians with ES expertise was convened for two stages. In Stage 1, two focus group discussions were recorded, transcribed, analyzed, and thematically summarized. In Stage 2, panel members completed a member-check survey, and panelists reviewed a proposed outline for an OT-CG ES guide, rating the desirability of each section. Online expert panel. A purposive sample of occupational therapy clinicians eligible to administer ES, actively using ES with SCI, and employed at preeminent SCI centers. An outline for an OT-CG to support consistent clinical use of ES among occupational therapy practitioners was developed. Three themes emerged: difficulty using clinical practice guidelines for electrical stimulation, lack of clinical examples to guide specific electrical stimulation treatment activities, and modifications to existing guidelines. An outline for a proposed guideline was created; ideally, such a manual would improve treatment fidelity and predictable patient outcomes for those with SCI. What This Article Adds: A novel outline for an OT-CG was developed to provide treatment fidelity, structure to treatment approaches, and a basis for future scholarly study.

Some Electrical Stimulation Methods for Articular Cartilage Regeneration

Bioelectrical signals can regulate a wide range of cellular activities in living organisms, including division, differentiation, etc. The physiological properties of stem cell cells are regulated by artificial input of electrical stimuli, including electric and electromagnetic fields, to promote cartilage repair by inducing stem cell cellular differentiation toward cartilage. Electrical stimulation (ES) stimulates cartilage regeneration at the cellular level through three mechanisms: intricate interactions of the physical environment, growth factors (GFs), and signal transduction cascades. The relevant ways in which bioelectrical stimulation regulates cellular function are the subject of this review. The non-invasive nature of this and the fact that it is not dependent on exogenous growth factors offer great promise for the clinical application of ES. However, the precise mechanisms underlying how ES interacts with cells are not well understood and need a lot more investigation. Similarly, there is a certain variability in the means and parameters of ES in in vivo and in vitro experiments, which poses a great challenge for clinical applications. Here some feasible means of ES and specific ES parameters to provide ideas for subsequent clinical applications are reviewed.

전기 자극을 이용한 CD271 양성 중간엽줄기세포의 연골세포 분화능

Mesenchymal stem cells (MSCs) exhibit self-renewing capacity and multi-lineage differentiation potential. CD271 has been identified as a marker of the most homogeneous MSCs subset. In this study, we separated CD271 positive MSCs (CD271-MSCs) from canine adipose tissue-derived MSCs (AD-MSCs) using immunomagnetic selection method. Both CD271-MSCs and AD-MSCs showed similar morphology and expressed common immunophenotypic markers (CD34, CD44, and CD45). However, CD271-MSCs and AD-MSCs exhibited difference in chondrogenic differentiation potential. Specifically, CD271-MSCs exhibited increased expression levels of chondrocyte specific markers, collagen type II alpha 1 (COL2A1) and Aggrecan compared to AD-MSCs. Also, electrical stimulation (ES)-treated CD271-MSCs have a greater capacity for expressing heat shock protein 70 (HSP70), COL2A1, and Aggrecan compared to control without exogenous differentiation condition. This study might contribute to the differentiation potential of homogenous MSCs into cartilage cells by specific ES condition in the absence of exogenous differentiation agents.

Chondrogenic potential of animal adult stem cells through electrical stimulation

Background & Aim Mesenchymal stem cells (MSCs) represent an appealing alternative cell source for cartilage repair. There are studies that induce differentiation into cartilage cells by treating the growth factors in MSCs or altering the properties of MSCs by genetic modification. Electrical stimulation (ES) is known to guide the development and regeneration of many tissues. Use of low-frequency ES for therapeutic purposes has been increasing during the last decades. In this study, we exposed equine adipose tissue-derived MSCs (eAD-MSCs) to ES and assessed changes in the chondrogenic differentiation potential. Methods, Results & Conclusion The cells obtained from equine adipose tissue attached to culture plates and expanded in vitro. Flow cytometric analysis at third passage indicated that the cells were strongly positive for CD44, CD90, and CD105, but negative for CD13, CD34, and CD45. ES was applied to eAD-MSCs cultured under condition of high-density micro-mass under ES of 10 V/cm, with duration of 10 ms and a frequency of 2.0 Hz for three days. We compared chondrogenic differentiation potential of non-ES and ES condition. Expression levels of chondrogenic potential-related markers were examined by quantitative real-time RT-PCR. Articular cartilage is divided into a hyaline cartilage layer and a fibrous cartilage layer. Osteoarthritis (OA) is a disease caused by the natural degeneration of cartilage layer. From the beginning, OA of the middle stage leads to damage of the hyaline cartilage, and damage of the fibrous cartilage at the last stage. We observed the differentiation potential of eAD-MSCs into chondrocytes by specific ES in absence of exogenous growth factors. Gene expression of chondrogenic markers such as type II collagen (COL2A1), Aggrecan, and Sox9 was analyzed at 3 days of ES. Based on the mechanism that chondrocyte formation in articular cavity starts from the aggregation of cells, we observed the differentiation potential of eAD-MSCs into chondrocytes by specific ES in absence of exogenous growth factors. Therefore, this study might contribute to the differentiation of stem cells into cartilage cells by inducing pre-chondrogenic condensation under specific ES.

Condensation of feline adipose tissue-derived mesenchymal stem cells by electrical stimulation

Background & Aim There are many studies that induce differentiation into cartilage cells by treating the growth factors in mesenchymal stem cells (MSCs) or alter the properties of MSCs by genetic modification. However, studies on cartilage differentiation are still insufficient. Recently, many studies have been reported that stem cells can differentiate into various cells by electrical stimulation (ES). An important step in the process of cartilage differentiation is pre-chondrogenic condensation, which is the stage where cartilage formation begins by condensation of stem cells and cartilage cells in the microenvironment of the joint. Methods, Results & Conclusion ES was applied to feline adipose tissue-derived MSCs (fAD-MSCs) using an electrical stimulator, which is a multi-channel stimulator designed for chronic stimulation of bulk quantities of cells in culture. This instrument emits bipolar pulses to culture media immersed carbon electrodes of a 35 mm dishes. ES was applied to fAD-MSCs cultured under conditions of high-density micro-mass (2 × 105 cells/10 μL) under ES of 1∼20 V/cm, with a duration of 8 ms and a frequency of 5.0 Hz. At indicated time points, we observed size of micro-mass, density and shapes. To induce cell to cell communication, make fAD-MSCs into micromass (2 × 105 cells/10 μL), a mass of cells in a small space, and induce condensation through ES. Condensation behaviors of fAD-MSCs in micro-mass culture were examined using phase contrast images during culture for 3 days under ES. Consistently, micro-mass caused compact condensation by ES at specific condition. Time-course observations of condensation behaviors of fAD-MSCs in micro-mass culture were examined with phase contrast images during culture for 3 days in maintenance medium only (control), and maintenance medium under ES, respectively. As a result, time-dependent observations showed that ES induced gradual aggregation of fAD-MSCs into compact structures within 3 days. This study might contribute to the differentiation of MSCs cells into cartilage cells by inducing pre-chondrogenic condensation under specific ES.

Enabling single cell electrical stimulation and response recording via a microfluidic platform.

Electrical stimulation (ES) has been recognized to play important roles in regulating cell behaviors. A microfluidic device was developed for the electrical stimulation of single cells and simultaneous recording of extracellular field potential (EFP). Each single cell was trapped onto an electrode surface by a constriction channel for ES testing and was then driven to the outlet by the pressure afterward. This design allows the application of ES on and detection of EFP of single cells continuously in a microfluidic channel. Human cardiomyocytes and primary rat cortex neurons were tested with specific ES with the device. Each cell's EFP signal was detected and analyzed during the ES process. Results have shown that after applying specific ES on the excitable single cells, the cells evoked electrical responses. In addition, increased secretion of glutamic acid was detected from the stimulated neurons. Altogether, these results indicated that the developed device can be used to continuously apply ES on and accurately determine cell responses of single cells with shorter probing time. The throughput of the measurement can achieve 1 cell per minute, which is higher than the traditional ES methods that need culturing cells or manually positioning the cells onto the electrode surface. Before and after the application of ES, the cell viability had no significant change. Such a device can be used to study the biological process of various types of cells under electrical stimulation.

Changes in S100 Proteins Identified in Healthy Skin following Electrical Stimulation: Relevance for Wound Healing.

Targeted electrical energy applied to wounds has been shown to improve wound-healing rates. However, the mechanisms are poorly understood. The aim of this study was to identify genes that are responsive to electrical stimulation (ES) in healthy subjects with undamaged skin. To achieve this objective, study authors used a small, noninvasive ES medical device to deliver a continuous, specific, set sequence of electrical energy impulses over a 48-hour period to the skin of healthy volunteers and compared resultant gene expression by microarray analysis. Application of this specific ES resulted in differential expression of 105 genes, the majority of which were down-regulated. Postmicroarray analyses revealed there was commonality with a small number of genes that have previously been shown to be up-regulated in skin wounds, including venous leg ulcers. The specific sequence of ES applied continuously for 48 hours to the skin of healthy patients has the effect of modifying expression in a number of identified genes. The identification of the differential expression in this subset of genes in healthy subjects provides new potential lines of scientific inquiry for identifying similar responses in subjects with slow or poorly healing wounds.

Computational modeling of neurons: intensity-duration relationship of extracellular electrical stimulation for changes in intracellular calcium.

In many instances of extensive nerve damage, the injured nerve never adequately heals, leaving lack of nerve function. Electrical stimulation (ES) has been shown to increase the rate and orient the direction of neurite growth, and is a promising therapy. However, the mechanism in which ES affects neuronal growth is not understood, making it difficult to compare existing ES protocols or to design and optimize new protocols. We hypothesize that ES acts by elevating intracellular calcium concentration ([Ca(2+)]i) via opening voltage-dependent Ca(2+) channels (VDCCs). In this work, we have created a computer model to estimate the ES Ca(2+) relationship. Using COMSOL Multiphysics, we modeled a small dorsal root ganglion (DRG) neuron that includes one Na(+) channel, two K(+) channels, and three VDCCs to estimate [Ca(2+)]i in the soma and growth cone. As expected, the results show that an ES that generates action potentials (APs) can efficiently raise the [Ca(2+)]i of neurons. More interestingly, our simulation results show that sub-AP ES can efficiently raise neuronal [Ca(2+)]i and that specific high-voltage ES can preferentially raise [Ca(2+)]i in the growth cone. The intensities and durations of ES on modeled growth cone calcium rise are consistent with directionality and orientation of growth cones experimentally shown by others. Finally, this model provides a basis to design experimental ES pulse parameters, including duration, intensity, pulse-train frequency, and pulse-train duration to efficiently raise [Ca(2+)]i in neuronal somas or growth cones.

Electrical stimulation modulates osteoblast proliferation and bone protein production through heparin‐bioactivated conductive scaffolds

Electrical fields are known to interact with human cells. This principle has been explored to regulate cellular activities for bone tissue regeneration. In this work, Saos-2 cells were cultured on conductive scaffolds made of biodegradable poly(L-lactide) and the heparin-containing, electrically conducting polypyrrole (PPy/HE) to study their reaction to electrical stimulation (ES) mediated through such scaffolds. Both the duration and intensity of ES enhanced cell proliferation, generating a unique electrical intensity and temporal "window" within which osteoblast proliferation was upmodulated in contrast to the downmodulation or ineffectiveness in other ES regions. The favourable ES intensity (200 mV/mm) was further investigated in terms of the gene activation and protein production of two important osteoblast markers characterised by extracellular matrix maturation and mineralisation, that is alkaline phosphatase (ALP) and osteocalcin (OC). Both genes were found activated and the relevant protein production increased significantly following ES. In contrast, ES in the down-modulation region (400 mV/mm) suppressed the production of both ALP and OC. This work demonstrated that important osteoblast markers can be modulated with specific ES parameters mediated through conductive polymer substrates, providing a unique strategy for bone tissue engineering.

Changes of myogenic reactive oxygen species and interleukin-6 in contracting skeletal muscle cells.

The aim of this study was to measure changes in myotube reactive oxygen species (ROS) and the production of interleukin (IL)-6 in electrically stimulated mouse C2C12 skeletal muscle cells. After five days of differentiation, myotubes were stimulated using an electrical stimulator set at 45 V at a frequency of 5 Hz, with a pulse width of 20 ms. Acute stimulations were performed for 45, 60, 75, 90, or 120 min in each dish. ROSs were detected in the extracted cells directly using a fluorescent probe. IL-6 mRNA expression in C2C12 myotubes and IL-6 concentration in C2C12 myotube supernatants were determined using real-time PCR and ELISA, respectively. Compared with control cells, ROS generation was significantly increased at 45 min after the onset of stimulation (P < 0.01) and continued to increase, reaching a maximum at 120 min. IL-6 mRNA expression and IL-6 concentration in C2C12 cells were significantly increased after 75 min (P < 0.01) and 120 min (P < 0.05) of electrical stimulation (ES) compared with the control cells. Our data show that a specific ES intensity may modulate ROS accumulation and affect IL-6 gene expression in contracting skeletal muscle cells.