Pressure Injuries Treated With Anodal and Cathodal High-voltage Electrical Stimulation: the Effect on Blood Serum Concentration of Cytokines and Growth Factors in Patients With Neurological Injuries. A Randomized Clinical Study

Abstract

The aim of this study was to determine whether anodal and cathodal high-voltage monophasic pulsed currents (HVMPC) provided to the area of a pressure injury (PI) change the blood level of cytokines (interleukin [IL]-1β, IL-10, and tumor necrosis factor [TNF]-α) and growth factors (insulin-like growth factor [IGF]-1 and transforming growth factor [TGF]-β1) in patients with neurological injuries and whether the level of circulatory cytokines and growth factors correlates with PI healing progression. This study was part of a randomized clinical trial on the effects of HVMPC on PI healing. All patients with neurological injuries (spinal cord injury, ischemic stroke, and blunt trauma to the head) and a stage 2, stage 3, or stage 4 PI of at least 4 weeks' duration hospitalized in one rehabilitation center were eligible to participate if older than 18 years of age and willing to consent to donating blood samples. Exclusion criteria included local contraindications to electrical stimulation (cancer, electronic implants, osteomyelitis, tunneling, necrotic wounds), PIs requiring surgical intervention, patients with poorly controlled diabetes mellitus (HbA1C > 7%), critical wound infection, and/or allergies to standard wound treatment. Participants were randomly assigned to 1 of 3 groups: anodal (AG) or cathodal (CG) HVMPC treatment (154 μs; 100 Hz; 360 µC/sec; 1.08 C/day) or a placebo (PG, sham) applied for 50 minutes a day, 5 days per week, for 8 weeks. TNF-α, IL-1β, IL-10, TGF-β1, and IGF-1 levels in blood serum were assessed using the immunoenzyme method (ELISA) and by chemiluminescence, respectively, at baseline and week 4. Wound surface area measurements were obtained at baseline and week 4 and analyzed using a digitizer connected to a personal computer. Statistical analyses were performed using the maximum-likelihood chi-squared test, the analysis of variance Kruskal-Wallis test, the Kruskal-Wallis post-hoc test, and Spearman's rank order correlation; the level of significance was set at P ≤.05. Among the 43 participants, 15 were randomized to AG (mean age 53.87 ± 13.30 years), 13 to CG (mean age 51.08 ± 20.43 years), and 15 to PG treatment (mean age 51.20 ± 14.47 years). Most PIs were located in the sacral region (12, 74.42%) and were stage 3 (11, 67.44%). Wound surface area baseline size ranged from 1.00 cm2 to 58.04 cm2. At baseline, none of the variables were significantly different. After 4 weeks, the concentration of IL-10 decreased in all groups (AG: 9.8%, CG: 38.54%, PG: 27.42%), but the decrease was smaller in the AG than CG group (P = .0046). The ratio of pro-inflammatory IL-10 to anti-inflammatory TNF-α increased 27.29% in the AG and decreased 26.79% in the CG and 18.56% in the PG groups. Differences between AG and CG and AG and PG were significant (AG compared to CG, P = .0009; AG compared to PG, P = .0054). Other percentage changes in cytokine and growth factor concentration were not statistically significant between groups. In the AG, the decrease of TNF-α and IL-1β concentrations correlated positively with the decrease of PI size (P <.05). Anodal HVMPC elevates IL-10/TNF-α in blood serum. The decrease of TNF-α and IL-1β concentrations in blood serum correlates with a decrease of PI wound area. More research is needed to determine whether the changes induced by anodal HVMPC improve PI healing and to determine whether and how different electrical currents affect the activity of biological agents responsible for specific wound healing phases, both within wounds and in patients' blood. In clinical practice, anodal HVMPC should be used to increase the ratio of anti-inflammatory IL-10 to pro-inflammatory TNF-α , which may promote healing.