Search Results (133)

Cell membrane capacitance (C_m) is a potential biomarker that reflects the structural and functional integrity of cell membranes. It is essential for physiological processes such as signal transduction, ion transport, and cellular homeostasis. In clinical practice, C_m can be determined using bioimpedance spectroscopy (BIS), a non-invasive technique for analysing the intrinsic electrical properties of biological tissues across a range of frequencies. C_m may be relevant in various clinical fields, where high capacitance is associated with healthy and intact membranes, while low capacitance indicates cellular damage or disease. Despite its promise as a prognostic indicator, several knowledge gaps limit the broader clinical application of C_m. These include variability in measurement techniques (e.g., electrode placement, frequency selection), the lack of standardised measurement protocols, uncertainty on how C_m is related to pathology, and the relatively low amount of C_m research. By addressing these gaps, C_m may become a valuable tool for examining cellular health, early disease detection, and evaluating treatment efficacy in clinical practice. This review explores the fundamental principles of C_m measured with the BIS technique, its mathematical basis and relationship to the biophysical Cole model, and its potential clinical applications. It identifies current gaps in our knowledge and outlines future research directions to enhance the understanding and use of C_m. For example, C_m has shown promise in identifying membrane degradation in sepsis, predicting malnutrition in anorexia nervosa, and as a prognostic factor in cancer. Full article

The risk of developing symptomatic knee osteoarthritis (KOA) during a lifetime, i.e., pain, aching, or stiffness in a joint associated with radiographic KOA, was estimated in 2008 to be around 40% in men and 47% in women. The clinical and scientific communities lack an efficient diagnostic method to effectively monitor, evaluate, and predict the evolution of KOA before and during the therapeutic protocol. In this review, we summarize the main methods that are used or seem promising for the diagnosis of osteoarthritis, with a specific focus on non- or low-invasive methods. As standard diagnostic tools, arthroscopy, magnetic resonance imaging (MRI), and X-ray radiography provide spatial and direct visualization of the joint. However, discrepancies between findings and patient feelings often occur, indicating a lack of correlation between current imaging methods and clinical symptoms. Alternative strategies are in development, including the analysis of biochemical markers or acoustic emission recordings. These methods have undergone deep development and propose, with non- or minimally invasive procedures, to obtain data on tissue condition. However, they present some drawbacks, such as possible interference or the lack of direct visualization of the tissue. Other original methods show strong potential in the field of KOA monitoring, such as electrical bioimpedance or near-infrared spectrometry. These methods could permit us to obtain cheap, portable, and non-invasive data on joint tissue health, while they still need strong implementation to be validated. Also, the use of Artificial Intelligence (AI) in the diagnosis seems essential to effectively develop and validate predictive models for KOA evolution, provided that a large and robust database is available. This would offer a powerful tool for researchers and clinicians to improve therapeutic strategies while permitting an anticipated adaptation of the clinical protocols, moving toward reliable and personalized medicine. Full article

The monitoring of peripheral electrical bioimpedance (EBI) variations is a promising method that has the potential to replace invasive or burdensome techniques for cardiovascular measurements. Segmental or continuous recording of peripheral pulse waves can serve as a basis for calculating prognostic markers like pulse wave velocity (PWV) or include parameters such as pulse transit time (PTT) or pulse arrival time (PAT) for noninvasive blood pressure (BP) estimation, as well as potentially novel cardiovascular risk indicators. However, several technical, analytical, and interpretative aspects need to be resolved before the EBI method can be adopted in clinical practice. Our goal was to investigate and improve the application of EBI, executing its comparison with other cardiovascular assessment methods in patients hospitalized for coronary catheterization procedures. Methods: We analyzed data from 44 non-acute patients aged 45–74 years who were hospitalized for coronary catheterization at East Tallinn Central Hospital between 2020 and 2021. The radial EBI and electrocardiogram (ECG) were measured simultaneously with central and contralateral pressure curves. The Savitzky–Golay filter was used for signal smoothing. The Hankel matrix decomposer was applied for the extraction of cardiac waveforms from multi-component signals. After extracting the cardiac component, a period detection algorithm was applied to EBI and blood pressure curves. Results: Seven points of interest were detected on the pressure and EBI curves, and four with good representativeness were selected for further analysis. The Spearman correlation coefficient was low for all but the central and distal pressure curve systolic upstroke time points. A high positive correlation was found between PWV measured both invasively and with EBI. The median value of complimentary pulse wave velocity (CPWV), a parameter proposed in the paper, was significantly lower in patients with normal coronaries compared to patients with any stage of coronary disease. Conclusions: With regard to wearable devices, the EBI-derived PAT can serve as a substrate for PWV calculations and cardiovascular risk assessment, although these data require further confirmation. Full article

The diagnosis of obesity is conventionally determined by the Body Mass Index (BMI), with a threshold of 30 being extensively accepted. However, the validity of this cutoff point is subject to variation due to ethnic differences, and its accuracy in the Mexican population remains unvalidated. This cross-sectional, observational, and analytical study endeavored to assess the diagnostic performance of BMIs ≥ 30 in comparison to body fat determination using bioimpedance. A total of 715 Mexican adults, aged over 18 years were analyzed. Anthropometric measurements, including weight, height, and BMI, were recorded, and body fat percentage was assessed. The results showed that BMIs ≥ 30 had a sensitivity of 62.4%, a specificity of 93.9%, a positive predictive value (PPV) of 95.5%, and a negative predictive value (NPV) of 54%. In contrast, a BMI cut-off of ≥27 demonstrated superior diagnostic performance, with a sensitivity of 81.3%, specificity of 82.5%, PPV of 90.8%, and NPV of 67.3%. The chi-square test revealed a significant difference in obesity diagnosis between bioimpedance and BMIs ≥ 30 (p < 0.05). These findings suggest that the current BMI cutoff of ≥30 underestimates obesity diagnosis, while a cutoff of ≥27 may provide a more accurate diagnostic threshold, emphasizing the necessity for population-specific adjustments. Full article

Methods used in daily clinical practice for the assessment of the nutritional status in patients with inflammatory bowel disease (IBD) are often based on simple indices and may not be sufficient in the case of minor or early changes. The purpose of this study was to analyze the nutritional status in patients with IBD. Material and methods: The case–control study included 80 patients with IBD. The control group consisted of 80 healthy subjects matched based on age and gender. Body composition was measured using the electrical bioimpedance method. Results: Compared to the healthy women, the female patients with IBD had a significantly lower muscle mass (24.4 kg vs. 27.9 kg) and muscle strength (22.4 kg vs. 25.9 kg), as well as a lower MMI (7.8 kg/m² vs. 9.9 kg/m²). Based on these findings, sarcopenia was diagnosed in 37.5% of the female patients, significantly more often than in the control group. In the group of men, there were no significant differences between the healthy controls and patients in terms of body composition and the prevalence of underweight and sarcopenia. Conclusions: The patients with IBD were characterized by a poorer nutritional status than the healthy subjects, mainly in terms of fat-free body mass and muscle mass, and consequently a higher incidence of sarcopenia, especially in the female group. Full article

The main purpose of this study was to evaluate the morphological characteristics of a sample of young international elite basketball players to create new reference values, using both somatotype and Bioelectrical Impedance Vector Analysis (BIVA). Moreover, we analyze the influence of age and maturation on anthropometric characteristics. Anthropometric measures (stature, body mass, body circumferences, skinfold thicknesses, and diameters) have been collected in a sample of 153 young basketball players of different age categories. From these measures, the endo-, ecto-, and mesomorph somatotypes components were calculated. In addition, impedance measurements were performed with a hand-to-foot bioimpedance analyser, and, subsequently, BIVA was carried out and biological maturity was estimated. A principal component analysis (PCA) has been assessed to reduce somatotype dimensionality. Almost all the collected variables differed between age groups. As regards the somatotype, the majority of the athletes were mesomorph–ectomorphal and the degree of homogeneity of the sample was high; the somatotype is aligned with that of the older athletes. Strong relationships were observed between mesomorphy, age, and bio-electric phase angle. Moreover, a tolerance ellipse graph was proposed as a reference for young elite athletes in basketball, and a new PCA-based method with one component was created to synthesize somatotype contents (eigenvalue = 2.42, R² = 0.807). Reference values for basketball players are needed by researchers, coaches, and practitioners for the process of talent identification and development. There are too many biological features to easily account for during growth, and field personnel need synthetic and more reliable approaches. Full article

Background/Objectives: Observing a patient’s dietary behaviour before bariatric surgery may help to predict their diet (and indirectly, the rate of weight loss) after the procedure. Consequently, the aim of this study was to identify dietary patterns (DPs) in bariatric surgery candidates, as well as to assess the relationship between DPs, degree of obesity, and body composition. Methods: The participants were comprised of 117 bariatric surgery candidates. Data concerning their diet, lifestyle, and socioeconomic status was collected using the KomPAN^® questionnaire. The following three DPs were identified using a principal component analysis: ‘Sandwiches & Sweets’, ‘Fast Food, Convenience Food & Alcohol’ and ‘Prudent’. Baseline nutritional status and body composition using electric bioimpedance were assessed. Results: Differences were found between the DPs, degree of obesity, and body composition. The Prudent DP primarily involved a high consumption of healthy products. Following the Prudent DP, differentiated the degree of obesity and the patient’s body composition the most. In turn, the Fast Food, Convenience Food & Alcohol DP was associated with a higher likelihood of Degree III obesity and a very high visceral fat level (VFL). The Sandwiches & Sweets DP included the most participants with a very high VFL. Conclusions: The bariatric surgery candidates were shown to follow different diets, and different DPs could be identified. Patients with a higher degree of obesity followed a more beneficial DP, which was likely due to their higher awareness of the risks of morbidity in obesity and of post-surgical complications. Socioeconomic factors may attenuate the association between diet and the degree of obesity and body composition in bariatric surgery candidates. Full article

In recent years, various types of sensors have been developed at both millimeter (mm) and micrometer (µm) scales for numerous biomedical applications. Each design has its own advantages and limitations. This study compares the electrical characteristics and sensitivity of millimeter- and micrometer-scale sensors, emphasizing the superior performance of millimeter-scale designs for detecting type-2 diabetes. Elevated glucose levels in type-2 diabetes alter the complex permittivity of red blood cells (RBCs), affecting their rheological and electrical properties, such as viscosity, volume, relative permittivity, dielectric loss, and AC conductivity. These alterations may manifest as a unique bio-impedance signature, offering a diagnostic topology for diabetes. In view of this, various concentrations (ranging from 10% to 100%) of 400 µL of normal and diabetic RBCs suspended in phosphate-buffered saline (PBS) solution are examined to record the changes in bio-impedance signatures across a spectrum of frequencies, ranging from 1 MHz to 10 MHz. In this study, simulations are performed using the finite element method (FEM) with COMSOL Multiphysics^® to analyze the electrical behavior of the sensors at both millimeter (mm) and micrometer (µm) scales. These simulations provide valuable insights into the performance parameters of the sensors, aiding in the selection of the most effective design by using this topology. Full article

Background: Malnutrition and muscle weakness are highly prevalent in critically admitted patients. To overcome sarcopenia and muscle weakness, physical activity and neuromuscular electric stimulation have been introduced with limited efficacy. Thus, several anabolic remedies have been introduced. An adequate increase in protein support according to indirect calorimetry and body composition and methyl hydroxybutyrate (HMB) is emerging. Therefore, we wanted to investigate the impact of HMB-enriched whey formula on the nutritional status, muscle weakness, and clinical course of critically ill patients undergoing nutritional status multimodal assessment and physical rehabilitation. Methods: We consecutively enrolled critically ill adult patients admitted to the intensive care unit (ICU) of “Santa Maria Hospital”, Terni, Italy. All patients underwent preliminary anthropometric, laboratory tests, nutritional (bioimpedance vector analysis and indirect calorimetry), and ultrasound muscle assessment at admission (T0). Laboratory tests monitoring continued throughout the ICU stay. Nutritional and muscle strength assessment was taken weekly throughout the patient’s ICU stay. All patients were enterally administered with a whey protein-enriched formula. Ten days after admission (during the physical rehabilitation period), patients were randomly administered a mixture of essential amino acids and methyl hydroxybutyrate (HMB). Results: We consecutively enrolled 54 ICU patients. At the baseline, survivors (n = 46) were significantly younger than non-survivors. The latter had a worse SAPS II score, nutritional status, and risk, with no significant difference in basal metabolism. Prealbumin values significantly correlated with improved nutritional status and metabolism. Starting from 10 days upon ICU admission, the pennation angle (used as a measure of muscle strength) significantly correlated with the improvement in nutritional status. Whey proteins were well tolerated. Its administration showed a tendency to improve the pennation angle. No specific effect of the mixture containing essential amino acids and methyl hydroxybutyrate was observed. Nutritional status improvement and the rise of basal metabolism were significantly correlated with the extubation time. On the other hand, the reduction in muscle weakness was not significantly correlated with the timing of extubation. Conclusions: Whey protein formula administration can significantly improve nutritional status and basal metabolism in ICU patients. This is reflected in improved muscle strength. Whey protein administration shows a tendency toward a rise in pennation angle. A similar and non-specific trend was observed upon HMB mixture add-one. Further prospective large-scale controlled studies are needed to confirm these promising results. Full article

Mesenchymal stem cell (MSC) treatments take advantage of the ability of these cells to migrate to target sites, although they have been shown to move in response to tumor influence. Currently, tools are being developed to detect these opportune changes in cellular behavior patterns. No reports of such changes in the morphological patterns or migration of MSCs in the presence of a tumor environment, which would provide information of high diagnostic value, have been made. We determined the changes in the cytoskeleton and migration of MSCs exposed to the secretome of breast tumor cells via bioimpedance records. MSCs were cultured and incubated in the presence of 24 and 48 h secretomes of the MCF-7 tumor cell line. The proliferation, migration, morphology, cytoskeleton, and electrical bioimpedance were evaluated at 48 h for cells treated with 24 and 48 h secretomes. Secretomes induced early morphological changes related to the migration of MSCs, directly confirmed via bioimpedance, but no changes in cell proliferation were found. These changes cannot be related to a transformation or malignancy phenotype. The modification of the bioimpedance patterns recorded from the first hours suggests that this method can be applied in an innovative way to detect early changes in a cellular population in the clinical diagnostic setting. Full article

Background/Objectives: Oral cancer (OC) is a disease with poor prognosis mainly due to late diagnosis. There is considerable interest in the use and development of rapid, point of care (POC) non-invasive methods that can accelerate the diagnostic process. Bioimpedance (BI) is resistance to the passage of electric currents through tissue that reflects structural changes in the tissue. The aim of this study was to determine the spectrum of BI values in patients with oral cancer, to compare them with other oral lesions and healthy controls, and to determine the diagnostic value of the BI-based method for diagnosis of OC. Methods: Ninety-three participants divided into three groups participated in this study. The first group (31 participants) consisted of patients with histologically confirmed OC, the second group (31 participants) consisted of patients with an active reticular form of oral lichen planus (positive controls; OLP) and the third group (31 participants) consisted of healthy controls. In OC and OLP patients, BI was measured at three points (non-ulcerated lesional mucosa, clinically unaffected perilesional mucosa and unaffected mucosa on the contralateral side). In healthy controls, BI was measured on a healthy mucosa in the corresponding anatomical region. Measurements were performed at nine frequencies (1, 2, 5, 7, 10, 20, 70 and 100 kHz). Results: In OC patients, BI values in the lesion were significantly lower than BI values in clinically intact perilesional mucosa and the unaffected contralateral side at all frequencies. Furthermore, BI values of the clinically intact perilesional mucosa were significantly lower than the BI values of the healthy contralateral mucosa at frequencies of 1 kHz, 2 kHz, 5 kHz, 7 kHz and 10 kHz. Patients with OC had significantly lower BI values compared to patients with OLP and individuals with healthy oral mucosa at all frequencies. Conclusions: This study demonstrated the very good to excellent ability of this method to detect OC lesions, which needs to be confirmed by further studies on a larger number of participants. Full article

The placenta plays a critical role in nutrient and oxygen exchange during pregnancy, yet the effects of medicinal drugs on this selective barrier remain poorly understood. To overcome this, this study presents a cost-effective bioimpedance spectroscopy (BIS) system to assess tight junction integrity and monolayer formation in BeWo b30 cells, a widely used model of the multinucleated maternal–fetal exchange surface of the placental barrier. Cells were cultured on collagen-coated porous membranes and treated with forskolin to induce controlled syncytialization. Electrical impedance was measured using an entry level impedance analyzer, while immunofluorescence staining was used to confirm monolayer formation and syncytialization. The measurements and staining confirmed the formation of a confluent monolayer on day 4. In fact, the electrical resistance tripled for treated samples indicating a more electrically restrictive barrier. This resistance remained constant for treated samples reflecting the intact barrier’s integrity over the next 3 days. The measurements show that, on day 4, the electrical capacitance of the cells decreased for the treated samples as opposed to the untreated samples. This reflects that the surface area of the BeWo b30 cells decreased when the samples were treated with forskolin. Finally, a COMSOL model was developed to explore the effects of electrode positioning, depth, and distance on TEER measurements, explaining discrepancies in the literature. In fact, there was a substantial 97% and 39.4% difference in the obtained TEER values. This study demonstrates the AD2 device’s feasibility for monitoring placental barrier integrity and emphasizes the need for standardized setups for comparable results. The system can hence be used to analyze drug effects and nutrient transfer across the placental barrier. Full article

Objectives: Early detection of cardiovascular diseases and their pre-existing conditions, arteriosclerosis and atherosclerosis, is crucial to increasing a patient’s chance of survival. While imaging technologies and invasive procedures provide a reliable diagnosis, they carry high costs and risks for patients. This study aims to explore impedance plethysmography (IPG) as a non-invasive and affordable alternative for diagnosis. Methods: To address the current lack of large-scale, high-quality impedance data, we introduce arterioscope.sim, a simulation platform that models arterial blood flow and computes the electrical conductivity of blood. The platform simulates bioimpedance measurements on specific body segments using patient-specific parameters. The study investigates how introducing arterial diseases into the simulation affects the bioimpedance signals. Results: The simulation results demonstrate that introducing atherosclerosis and arteriosclerosis leads to significant changes in the computed signals compared to simulations of healthy arteries. Furthermore, simulation of a patient-specific healthy artery strongly correlates with measured signals from a healthy volunteer. Conclusions and significance: arterioscope.sim effectively simulates bioimpedance signals in healthy and diseased arteries and highlights the potential of using these signals for early diagnosis of arterial diseases, offering a non-invasive and cost-effective alternative to traditional diagnostic methods. Full article

This research re-evaluates the prevalence of obesity in a cohort of 432 Slovenian adults two years after an initial population-based cross-sectional examination, utilizing the World Health Organization’s body mass index (BMI) and total body fat percentage (FAT%) classifications. Herein, a medically approved electrical bioimpedance monitor was used to analyse body composition, and the results revealed a significant increase in the percentage of individuals classified as having overweight or obesity on the basis of BMI, from 40.7% initially to 45.2% at follow-up (FU); however, these percentages were notably higher in males than in females. The increases in body mass, BMI, fat mass, and FAT% were observed mainly in adult females, whereas in adult males, the increases in BM and BMI were attributed to fat-free mass (FFM) rather than fat mass. In this study, BMI was also compared with the FAT% obesity classification, and the BMI classification was shown to result in significantly fewer participants with obesity in both measures. However, the proportion of participants with obesity based on the two classifications did not differ substantially between the initial and FU measurements. In this study, mixed linear models were used to analyse overall trends and subgroup variations and highlight the importance of considering sex, age, and time of measurement when assessing body composition metrics. These findings emphasize the need for personalized health assessments and the importance of measuring body composition to evaluate adult obesity more accurately for both clinical assessments and public health policies. The state, in collaboration with social initiatives and industrial stakeholders, should prioritize these data and advance public health through innovative educational and awareness initiatives that are founded on robust scientific principles and that empower and promote the adoption of a healthy, active lifestyle. Full article

Background: This study examined electrical bioimpedance as a biomarker for intracochlear tissue changes after cochlear implant surgery, comparing monopolar, three-point, and four-point impedance measurements over time and evaluating different measurement systems and approaches. Methods: Impedance measurements were obtained from 21 participants during surgery and at four postoperative stages. Monopolar impedances were recorded using the Bionic Ear Data Collection System (BEDCS) and the Active Insertion Monitoring (AIM) system. Three- and four-point impedances were recorded directly using BEDCS, and indirect three-point impedances were additionally derived from Electrical Field Imaging matrices recorded using BEDCS or AIM. Results: There was an 11% relative error between monopolar measurements from BEDCS and AIM and a 25% discrepancy between direct and indirect three-point measurements. Despite this, direct and indirect measurements from both systems were useful for tracking postoperative impedance shifts. Three- and four-point measurements showed a strong relationship both during and after surgery. Our results suggest that three- and four-point measurements are more specific than monopolar impedances in capturing localized tissue changes. Conclusions: Three- and four-point impedance measurements are potential markers of intracochlear tissue changes over time. While direct three-point impedance measurements offer higher accuracy, indirect measurements provide a feasible alternative for monitoring intracochlear changes in clinical settings lacking the option of direct measurements. Full article