Efeitos da bioestimulação transneural do nervo vago utilizando Terapia de Fotobiomodulação (FBM) sobre marcadores autonômicos e hemodinâmicos de pacientes com síndrome metabólica

Abstract

INTRODUCTION: Metabolic Syndrome (MS) consists of a grouping of conditions: central obesity, increased levels of glucose, dyslipidemia (increased triglycerides and low levels of HDL-cholesterol) and increased blood pressure, with chronic inflammation being the main common pathophysiological element . In the last decade, numerous studies have shown that parasympathetic stimulation (vagal or cholinergic) can reflexively reduce the inflammatory response in different scenarios. This recognition led to the proposition of the term “anti-inflammatory cholinergic reflex” for this mechanism. Activation of the anti-inflammatory reflex can be achieved by direct vagal stimulation or with the use of drugs. Anti-cholinesterase drugs can be effective, but lower cost alternatives with fewer side effects deserve investigation, especially transneural photobiostimulation of the vagus nerve. OBJECTIVE: The aim of this study is to evaluate the effects of transneural photobiostimulation therapy of the vagus nerve using Low Intensity Laser (LLL) on autonomic and hemodynamic markers in a patient with Metabolic Syndrome. METHODOLOGY: This is a prospective, randomized, open and intervention clinical study. 40 patients of both sexes, aged 25 to 60 years, who met the inclusion criteria were included. They were randomized into 2 distinct groups (Group 1 – LBI; Group 2 – Placebo). The anthropometric assessment consisted of the following items: Abdominal circumference (cm) – passing at the height of the umbilical scar, using a measuring tape. Height (m) – measured by the stadiometer. Total body mass (kg) – scale. Body mass index (BMI) – weight (kg)/height2(m). The records of hemodynamic variables through, systolic (SBP), diastolic (DBP), mean (MAP), heart rate (HR), cardiac output (DC) and total peripheral vascular resistance (TPR) blood pressure. continuous and non-invasive, beat-to-beat, using the Finomiter® pressure monitor. Autonomic variables (HRV) were analyzed in the time and frequency domain (spectral analysis) using specific software (Matlab). The spectral power was integrated into three frequency bands of interest - High frequencies (HF), Low frequencies (LF) and Very low frequencies (VLF) and the ratio between two of them (LF/HF) was performed to assess the autonomic balance. Dosimetric Parameters used: CW LLLT (λ) = 808nm wavelenght (infrared), Power= 25mW, Time= 3 min into the auricular pavilion of Left cymba conchae, Intensity = 156 mW/cm2, Fluence = 28J/cm2, Energy/pt. = 4,5 J, Laser spot size= 0,16 cm2. Transneural nerve stimulation was performed using the LBI model (Cosmedical), intended for use in Medicine, being regulated and authorized by ANVISA. RESULT: After the 8 estimates of LLLT stimulation, comparing baseline moments and after 8 weeks, the TG presents: AC (115 ± 14 vs 111 ± 15; p = 0.999), BMI (36 ± 5 vs 35 ± 6 ; p = 0.810), Glucose (92 ± 10 vs 96 ± 8; p = 0.687), Total cholesterol (180 ± 38 vs 183 ± 65; p = 0.944), HDL-cholesterol (41 ± 6 vs 44 ± 9; p = 0.918), Triglycerides (136 ± 36 vs 108 ± 33; p = 0.250), Insulin (14.0 ± 5 vs 14.0 ± 11; p = 0.850), Homa-IR (3.2 ± 1.2 vs 3.5 ± 2.6; p = 0.888), PCR (0.5 ± 0.3 vs 1.8 ± 2.0; p = 0.283), office SBP and beat-to-beat, respectively (131 ± 15 vs 128 ± 12; p = 0.764 and 134 ± 10 vs 122 ± 10; p = 0.819), office DBP and beat-to-beat, respectively (80 ± 8 vs 80 ± 15; p = 0.999 and 77 ± 5 vs 69 ± 6; p = 0.755), office HR and beat-to-beat, respectively (72 ± 12 vs 69 ± 17; p = 0.497 and 68 ± 14 vs 70 ± 2; p = 0.935), RMSSD (37 , 0 ± 20.2 vs 32.4 ± 22.3; p = 0.853), LF (un) (54.6 ± 14.3 vs 41.0 ± 11.7; p = 0.230); HF (nu) (45.4 ± 14.3 vs 59.0 ± 11.7; p = 0.230) and LF / HF (1.8 ± 1.1 vs 0.8 ± 0.4; p = 0.316) . No associated changes were observed comparing the two moments of analysis in the GP (p>0.05). CONCLUSION: Based on the results of this research, laser therapy did not denote a favorable response in patients with MS on hemodynamic and autonomic markers. However, due to the limitations already pointed out, in particular the small number of patients who completed the protocol, future studies should continue to be carried out to define the real role of laser vagus nerve stimulation in patients with MS.