Therapeutic electric stimulation does not affect immune status in healthy individuals - a preliminary report

The impact of pelvic floor electrical stimulation on vaginal microbiota and immunity

Pelvic floor electrical stimulation (ES) is an effective treatment for pelvic floor dysfunction. However, the impact of ES on vaginal microbiota and local inflammatory response is yet poorly understood. Therefore, we designed a longitudinal study to investigate the impact of ES on vaginal microbiota and cytokines. A total of 170 participants were recruited into the study at Peking University International Hospital, Beijing, China, from December 2021 to April 2022. They were divided into two groups concerning the follow-up: long-term cohort (n = 147) following up to seven treatment sessions and short-term cohort (n = 23) following up to 7 h after a 30-min treatment. Paired vaginal discharge samples were collected from 134 individuals. Vaginal microbiota was characterized by 16S rRNA sequencing, and local cytokines concentrations were detected by the cytometric bead array method. A significant increase in the relative abundance of Lactobacillus spp. was observed after ES treatment (P < 0.001). In addition, L. crispatus (P = 0.012) and L. gasseri (P = 0.011) also increased significantly. Reduced microbial diversity was observed in the vaginal microbiota after the treatment. In the long-term cohort, a significant downregulation of IFN-γ, IL-2, IL-4, IL-10, IL-17A, and TNF-α was compared with baseline. However, the short-term cohort presented with an elevated IL-6 level at 7 h after the treatment. In conclusion, this study suggested that transvaginal electrical stimulation might help to restore and maintain a healthy vaginal microbiota dominated by Lactobacillus, reducing the risk of vaginal inflammation.

Bioactive polymeric materials and electrical stimulation strategies for musculoskeletal tissue repair and regeneration

Electrical stimulation (ES) is predominantly used as a physical therapy modality to promote tissue healing and functional recovery. Research efforts in both laboratory and clinical settings have shown the beneficial effects of this technique for the repair and regeneration of damaged tissues, which include muscle, bone, skin, nerve, tendons, and ligaments. The collective findings of these studies suggest ES enhances cell proliferation, extracellular matrix (ECM) production, secretion of several cytokines, and vasculature development leading to better tissue regeneration in multiple tissues. However, there is still a gap in the clinical relevance for ES to better repair tissue interfaces, as ES applied clinically is ineffective on deeper tissue. The use of a conducting material can transmit the stimulation applied from skin electrodes to the desired tissue and lead to an increased function on the repair of that tissue. Ionically conductive (IC) polymeric scaffolds in conjunction with ES may provide solutions to utilize this approach effectively. Injectable IC formulations and their scaffolds may provide solutions for applying ES into difficult to reach tissue types to enable tissue repair and regeneration. A better understanding of ES-mediated cell differentiation and associated molecular mechanisms including the immune response will allow standardization of procedures applicable for the next generation of regenerative medicine. ES, along with the use of IC scaffolds is more than sufficient for use as a treatment option for single tissue healing and may fulfill a role in interfacing multiple tissue types during the repair process.

Therapeutic electrical stimulation and immune status in healthy men

In physical and rehabilitation medicine, there are few reports on the effects of therapeutic low-frequency electrical stimulation on the immune response of the organism, even though electrical stimulation is used widely in clinical practice and sports medicine. The aim of our study was to examine the possible immunological consequences of moderate transcutaneous neuromuscular electrical stimulation (NMES) for quadriceps muscle strengthening in healthy individuals. The study included twelve healthy male adult volunteers (mean age 42 years) without contraindications for electrical stimulation. At the beginning and immediately after a 20-min session of NMES of quadriceps muscles, peripheral blood was collected to analyse the biochemical blood components (creatinine, creatine kinase, estimated glomerular filtration rate, cortisol), differential white blood cell count and immunological parameters. The intensity of NMES was set at maximum tolerance, eliciting on average about one-sixth of the maximum voluntary isometric contraction of the same leg. No statistically significant differences in the average group level were found in any of the measured biochemical blood components, white blood cell count or immunological parameters after the NMES session. On an individual level, the changes in creatine kinase, estimated glomerular filtration rate, basophils and some immunological parameters correlated with changes in the cortisol level. We can conclude that moderate transcutaneous low-frequency electrical stimulation for quadriceps muscle strengthening used in our study did not induce essential changes in immune status in healthy men.