Search Results (955)

Background: Aging exerts a progressive and multifaceted impact on the microcirculatory system, undermining the structural and molecular integrity that sustains endothelial stability across both peripheral and cerebral vascular territories. A sustained shift toward oxidative imbalance, chronic low-grade inflammation, and progressive endothelial exhaustion converges to destabilize microvascular networks, linking peripheral artery disease (PAD) with heightened susceptibility to cerebral microvascular dysfunction and neurovascular decline. As redox homeostasis deteriorates, endothelial cells progressively lose barrier-selective properties, intercellular communication with pericytes weakens, and pro-thrombotic tendencies subtly emerge, creating a permissive environment for early neurovascular injury and impaired cerebrovascular resilience. Methods: This narrative review integrates mechanistic evidence derived from experimental, clinical, and translational studies examining the interplay between oxidative stress, inflammatory signaling cascades, endothelial senescence, and blood–brain barrier (BBB) disruption across peripheral and cerebral microvascular systems. A comparative framework was applied to PAD and cerebral microcirculatory pathology to identify convergent molecular drivers and systemic mechanisms underlying endothelial deterioration. Results: Accumulating evidence demonstrates that oxidative stress disrupts endothelial mitochondrial function, compromises tight junction architecture, and accelerates angiogenic failure. Concurrent inflammatory activation amplifies these alterations through cytokine-mediated endothelial activation, enhanced leukocyte adhesion, and promotion of a pro-thrombotic microenvironment. Progressive endothelial senescence consolidates these insults into a persistent state of microvascular dysfunction characterized by diminished nitric oxide bioavailability, capillary rarefaction, and compromised barrier integrity. Notably, these pathological features are shared between PAD and the aging cerebral circulation, reinforcing the concept of a unified systemic microvascular aging phenotype. Conclusions: Microvascular failure in the aging brain should be understood as an extension of systemic endothelial deterioration driven by oxidative stress, chronic inflammation, and senescence-associated vascular exhaustion. Recognizing the shared molecular architecture linking peripheral and cerebral microcirculatory dysfunction offers a strategic framework for developing targeted therapeutic interventions aimed at restoring endothelial resilience, stabilizing BBB integrity, and preserving neurovascular homeostasis in aging populations. Full article

This study evaluates the impact of capillary refill time (CRT) modulation on photoplethysmography (PPG) signals for improved non-invasive continuous blood pressure (CBP) estimation. Data from 21 healthy participants were collected, applying a standardized 9 N pressure for 15 s to induce CRT during 6-min sessions. PPG signals were segmented into 252 paired 30-s intervals (CRT-modulated and standard). Three machine learning models—ResNetCNN, LSTM, and Transformer—were validated using leave-one-subject-out (LOSO) and non-LOSO methods. CRT modulation significantly enhanced accuracy across all models. ResNetCNN showed substantial improvements, reducing mean absolute error (MAE) by up to 35.6% and mean absolute percentage error (MAPE) by up to 40.6%. LSTM and Transformer models also achieved notable accuracy gains. All models met the Association for the Advancement of Medical Instrumentation (AAMI) criteria (mean error < 5 mmHg; standard deviation < 8 mmHg). The findings suggest CRT modulation’s strong potential to improve wearable CBP monitoring, especially in resource-limited settings. Full article

Calcium is a key macroelement involved in a range of physiological processes in the body, and its concentration in blood is an important diagnostic indicator in various diseases. This work presents a novel rapid method for the point-of-care determination of total calcium content in patient blood, by applying a drop of capillary blood from a finger onto a hydrogel. Gelatin hydrogel, modified with an optical sensor for calcium, Arsenazo III, was used as a platform for the separation of blood into plasma and erythrocytes. A comparative analysis of various types of hydrogel materials (polyacrylamide, PVA, Fmoc-FF, carbomer, carbopol, gelatin) was performed, demonstrating that among the studied systems, only gelatin hydrogel is suitable as a platform for the determination of calcium in blood plasma. The binding of calcium ions from blood plasma with the calcium sensor embedded in the hydrogel leads to a change in the absorption spectrum of the system, enabling photometric determination of calcium concentrations below and above the normal range in blood plasma. Therefore, this rapid assay allows monitoring of calcium metabolism disorders in the human organism. The method is characterized by its speed, simplicity of sample preparation, and potential for integration into clinical practice. Full article

Profiling the blood–brain barrier (BBB) permeability of bioactive molecules during early drug development is critical for optimizing their pharmacokinetic profile. The in vivo ability of a compound to cross the BBB is measured by the log BB parameter; however, its determination requires costly and time-consuming animal experiments. This study aimed to develop a novel in vitro method for high-throughput prediction of log BB values. The approach combines experimental data from open-tubular capillary electrochromatography (CEC) and automated potentiometric titrations, including the CEC retention factor (k′), electropherograms, and physicochemical parameters pK_a and log D_7.4. The k′ parameter reflects BBB permeability using a capillary internally coated with liposomes that mimic a biological membrane. Preliminary CEC analyses were conducted for 25 neutral drugs at pH 7.4, revealing a promising correlation between the permeability parameters log k and log BB. The validation was extended to 57 ionized drugs, with additional determination of pK_a and log D_7.4. A regression model was developed: log BB = −2.45 + 0.1k′ + 0.3logD_7.4 + 0.27pK_a (R² = 0.64). Furthermore, the analysis of CEC electropherograms enabled the machine learning-based rapid classification of compounds using Dynamic Time Warping, k-Nearest Neighbors, and the Bag-of-SFA-Symbols in Vector Space model, yielding an accuracy of 0.81 and an F1_weighted score of 0.8. Full article

Photoacoustic (PA) velocimetry offers a promising solution to the limitations of conventional techniques for measuring blood flow velocity. Given its moderate penetration depth and high spatial resolution, PA imaging is considered suitable for measuring low-velocity blood flow in capillaries located at moderate depths. High-resolution measurements based on PA signals from individual blood cells can be achieved using a high-frequency transducer. However, high-frequency signals attenuate rapidly within biological tissue, restricting the measurable depth. Consequently, low-frequency transducers are required for deeper measurements. To date, PA flow velocimetry employing low-frequency transducers remains insufficiently explored. In this study, we investigated the effect of the concentration of particles that mimic blood cells within vessels under low-concentration conditions. The performance of flow velocity measurement was evaluated using an ultrasonic transducer (UST) with a center frequency of 10 MHz. The volume fraction of particles in the solution was systematically varied, and the spatially averaged flow velocity was assessed using two different distinct analysis methods. One method employed a time-shift approach based on cross-correlation analysis. Flow velocity was estimated from PA signal redpairs generated by particles dispersed in the fluid, using consecutive pulsed laser irradiations at fixed time intervals. The other method employed a pulsed Doppler method in the frequency domain, widely applied in ultrasound Doppler measurements. In this method, flow velocity redwas estimated from the Doppler-shifted frequency between the transmitted and received signals of the UST. For the initial analysis, numerical simulations were performed, followed by experiments based on displacement measurements equivalent to velocity measurements. The target was a capillary tube filled with an aqueous solution containing particles at different concentration levels. The time–domain method tended to underestimate flow velocity as particle concentration increased, whereas the pulsed Doppler method yielded estimates consistent with theoretical values, demonstrating its potential for measurements at high concentrations. Full article

Background/Objectives: Modifying standard foods to minimize postprandial glucose (PPG) and insulin excursions may benefit health. We conducted a randomized, double-blind, crossover study to compare postprandial responses to an isocaloric (~250 kcal) Standard Muffin (SM) containing refined flour and sugar versus a Modified Muffin (MM) consisting of wheat-free grains and low sugar levels in healthy individuals and individuals with type 2 diabetes (T2D). Subjects/Methods: Nineteen subjects (ten healthy, nine with T2D) participated in the trial. PPG responses were measured in capillary blood over 5 h to calculate the change in glucose from the baseline (ΔGLU), peak glucose (GLU_Peak), peak–nadir glucose (GLU_P-N), and 2 h incremental area under the curve (iAUC). Plasma insulin responses were quantified via assays. Results: Compared to the SM, the MM significantly reduced the GLU_Peak (55%), GLU_P-N (35%), and 2 h iAUC (80%). Within the cohort, the MM elicited a 68% reduction in the GLU_Peak response compared to the SM in individuals with T2D. Insulin was lower following the MM (−62%). Participants reported similar subjective taste and mouthfeel ratings. Conclusion: A novel MM decreased PPG and insulin responses compared to a SM, without compromising taste, thus highlighting salient features for T2D nutrition management. Full article

Chronic kidney disease (CKD) affects nearly 850 million people worldwide, and most patients with kidney failure are treated with kidney replacement therapy. Despite technological progress, venous congestion remains a major determinant of morbidity and mortality, and is often underdetected by conventional tools such as clinical evaluation, weight changes, blood pressure measurement, or bioimpedance. Point-of-care ultrasonography (PoCUS) has transformed this diagnostic landscape by providing real-time, physiology-based insights into both left- and right-sided filling pressures. In dialysis care, multiple or confluent B-lines and subtle pleural irregularities suggest elevated pulmonary capillary wedge pressure, while a dilated inferior vena cava (IVC) with reduced collapsibility and increased portal vein pulsatility indicate elevated right atrial pressures. Integrating these sonographic findings into a multiparametric assessment that also includes clinical assessment, bioimpedance, and biosensor feedback enhances diagnostic sensitivity and refines fluid management. Advanced practice nurses (APNs) trained in PoCUS can perform focused examinations of the lungs, IVC, portal venous system, arteriovenous access, and skeletal muscle, translating ultrasound findings into physiological interpretations that guide individualized ultrafiltration strategies and patient care. Nutritional ultrasound (NUS) further complements congestion assessment by quantifying muscle mass and quality, linking nutritional reserve and functional status with hemodynamic tolerance. The implementation of structured education, competency-based training, and standardized scanning protocols allows nurses to incorporate these techniques safely and reproducibly into daily dialysis workflows. By integrating PoCUS and NUS within interdisciplinary decision-making, nursing practice evolves from procedural to diagnostic, supporting early identification of congestion, protection of vascular access, and detection of malnutrition. This multiparametric, physiology-guided approach exemplifies the concept of precision nursing, where patient evaluation becomes continuous, individualized, and grounded in real-time pathophysiological insight. Full article

Background/objectives: Tropoelastin is a highly hydrophobic extracellular matrix protein responsible for the extensibility and elastic recoil of various organs. The Windkessel effect in blood vessels dampens pressure variations during the cardiac cycle to provide continuous perfusion of tissues, such as the fragile gill capillaries in fish. The teleost-specific whole-genome duplication was followed by structural and functional divergence of the duplicated tropoelastins, of which ElnB confers the uniquely low stiffness of the bulbus arteriosus. Methods: We have examined the diversity of tropoelastins in all major fish clades by searching for tropoelastin (eln) genes in the sequenced genomes. Duplication of eln genes in tetraploid salmonids and cyprinids was examined by maximum likelihood phylogenetic analysis, and cardiac eln expression in rainbow trout was quantified by qPCR. Results: The tetraploid salmonid genomes harbor two elna genes but a single elnb, except for the tandem duplicated elnb genes in sockeye salmon and lake whitefish, while the tetraploid common carp possesses four elna and elnb genes on separate chromosomes. Rainbow trout showed strong elastin staining in the larval bulbus and ventral aorta, and the bulbar expression of elnb was 15 times higher than the ventricular levels in juvenile fish. The expression of elna1 and elna2 was also significantly higher in the bulbus, and together their transcript levels were almost similar as the elnb levels. The overall hydrophobicity of the fish tropoelastins differed considerably among the species ranging from 28.6% in Emerald rockcod ElnB to 56.3% in lesser devil ray Eln, but showed no significant difference with the tetrapods examined, except for the lower hydrophobicity of teleost ElnB. Conclusions: The inclusion of tetrapods in the analysis revealed a positive relationship between ventral aortic blood pressure and tropoelastin hydrophobicity. Full article

Background/Objectives: This study aimed to evaluate the influence of mean blood glucose (MG) and glycemic variability (GV) during hospitalization on the risk of mortality in patients with diabetes mellitus (DM). Methods: We conducted a retrospective cohort study including patients with DM admitted to the Internal Medicine ward. The dependent variable was post-discharge mortality. Capillary glucose levels were collected, and MG, standard deviation (SD), and coefficient of variation (CV = SD/MG) were calculated. The predictive value of MG and GV, expressed as CV, for mortality was assessed, adjusting for hypoglycemic episodes and comorbidities. Survival analysis and multivariate Cox regression were performed. Results: A total of 276 patients were included, mean age of 77.6 ± 10.2 years, 146 (52.9%) were males. Heart failure was the leading cause of admission (40.4%). During a median follow-up of 2.7 years, 249 patients (90.2%) died, corresponding to 212 deaths per 1000 patient years (289 with CV > 0.29 vs. 168 with CV ≤ 0.29). In the multivariate Cox model, CV > 0.29 (HR = 1.60; 95% CI 1.23–2.08; p = 0.001) and MG > 140 mg/dL (HR = 1.71; 95% CI 1.16–2.51; p = 0.004) were independent predictors of mortality. Conclusions: Elevated MG and GV measured during hospitalization may help stratify mortality risk after discharge in patients with DM Full article

p17, the human immunodeficiency virus type 1 (HIV-1) matrix protein traditionally associated with viral assembly, has been recently investigated for its extracellular functions linked to vascular damage. This review examines the molecular and pathogenic signatures by which p17 and its variants (vp17s) contribute to endothelial activation, aberrant angiogenesis, and vascular inflammation, highlighting their relevance even under effective antiretroviral therapy (ART). Specifically, p17 exerts chemokine-like activities by binding to chemokine (C-X-C motif) receptor-1 and 2 (CXCR-1/2) on endothelial cells (ECs). This interaction triggers key signaling cascades, including the protein kinase B (Akt)-dependent extracellular signal-regulated kinase (ERK) pathway and endothelin-1/endothelin receptor B axis, driving EC motility, capillary formation, and lymphangiogenesis. Variants such as S75X demonstrate enhanced lymphangiogenic potency, associating them with tumorigenic processes involved in non-Hodgkin lymphoma (NHL) pathogenesis. Importantly, p17 promotes endothelial von Willebrand factor (vWF) storage and secretion, implicating a pro-coagulant state that may trigger the increased thromboembolic risks observed in HIV-positive patients. Furthermore, p17 crosses the blood–brain barrier (BBB) via CXCR-2-mediated pathways, contributing to neuroinflammation by activating microglia and astrocytes and amplifying monocyte chemoattractant protein-1 (MCP-1) levels, therefore playing a critical role in the development of HIV-associated neurocognitive disorders. Hence, the elaboration of potential therapeutic strategies finalized at inhibiting p17/vp17s’ interaction with their receptors could complement ART by addressing HIV-related neurovascular morbidity. Full article

Background/Objectives: Intrahepatic cholestasis of pregnancy (ICP) is associated with adverse perinatal outcomes. However, its metabolic consequences on newborns remain inadequately characterized. This study investigated amino acid, carnitine, and acylcarnitine profiles in neonates born to mothers with ICP. Methods: This retrospective study encompassed 299 neonates born to mothers with ICP. For comparative analysis, term infants without additional complications (ICP-term, n = 150) were compared with term controls (n = 150). Capillary blood samples collected at 24–48 h of life as part of newborn screening were analyzed using LC–MS/MS for acylcarnitine and amino acid profiles. Results: The ICP cohort exhibited a high preterm delivery rate (46.2%), with maternal bile acids negatively correlating with gestational age (r = −0.266, p < 0.001). No inborn errors of metabolism were observed. Elevated levels of amino acids (alanine, leucine/isoleucine, valine, tyrosine, arginine, glycine, and ornithine) and specific acylcarnitines (C5, C5-OH, C10:1, and C18:2), along with decreased levels of amino acids (argininosuccinic acid and glutamic acid) and specific acylcarnitines (C3, C5-DC, C6-DC, C14, C14:1, C16, C16:1, and C18:1-OH), were observed in ICP-term neonates (p < 0.05). Receiver operating characteristic curve analysis identified ornithine (area under the curve [AUC] = 0.74) and leucine/isoleucine (AUC = 0.73) as strong discriminators. A multivariable model integrating multiple metabolites achieved high accuracy (AUC = 0.86 ± 0.03). Conclusions: This first comprehensive characterization of neonatal metabolic alterations in ICP reveals amino acid metabolism, fatty acid oxidation, and mitochondrial function disruptions, suggesting fetal adaptation to a cholestatic intrauterine environment. Metabolomic profiling may improve understanding of maternal–fetal interactions and inform strategies for risk stratification and long-term monitoring. Full article

The paper provides a comprehensive review of the relationship between whole blood viscosity (WBV) and acute ischemic stroke (AIS) concerning AIS risk and type, and its treatment and prognosis. A significant increase in diastolic blood viscosity (DBV) at the onset of AIS was established in the small-artery occlusion stroke subtype. In patients with atherothrombotic causes of AIS, systolic (SBV) and DBV values were higher than in those with an embolic cause. The higher WBV at low shear rates on hospital admission is associated with an increased risk of early neurological deterioration and disease progression in the patients with AIS. Most studies reveal the association of increased WBV at the stroke onset with poor functional outcome after applying intravenous thrombolysis or endovascular thrombectomy. However, significant reduction in WBV after the combined use of these therapeutic methods in AIS patients was observed. Whole blood viscosity has an obvious effect on the risk of AIS, its clinical severity and outcome. Further research is needed due to the multiple devices and techniques used, like cone–plate viscometers, scanning capillary viscometers, EMS viscometers, parallel-plate rheometers and the different associations of WBV with some of the applied treatment strategies. Full article

Liver cancer is one of the most common and lethal malignant tumors worldwide, of which hepatocellular carcinoma (HCC) accounts for 80%. In the process of forming liver cancer, cancer cell metastasis is the only path. First, cancer cells need to adhere to the walls of capillaries, then penetrate blood vessels and enter liver tissue, resulting in liver cancer. Existing diagnostic methods for cancer cannot reveal and study this process, so we need to simulate the microenvironment in vitro and observe the metastasis mechanism of liver cancer cells based on this. This article describes the design and manufacture of a biomimetic capillary network to achieve this goal. By combining maskless laser direct writing with backside lithography, a biomimetic vascular network with a semi-circular cross-section was created that more closely resembles real capillaries. This article mainly studies the influence of topological structure on cell flow velocity, and simulates the flow velocity and pressure of cell solutions in vascular networks to investigate the differences between the biomimetic capillary network and the real situation, in order to further optimize and provide new ideas for the study of the liver cancer cell metastasis and the in vitro dynamic mechanism. Full article

Accurate, non-invasive glucose monitoring remains a major challenge in biomedical sensing. We present a high-sensitivity planar microwave biosensor that progresses from a 2-cell hexagonal array to an 8-cell hexagonal array, and finally to a 16-cell double-honeycomb (DHC-CSRR) architecture to enhance field confinement and resonance strength. Full-wave simulations using Debye-modeled glucose phantoms demonstrate that the optimized 16-cell array on a Rogers RO3210 substrate substantially increases the electric field intensity and transmission response |S₂₁| sensitivity compared with FR-4 and previous multi-CSRR designs. In vitro measurements using pharmacy-grade glucose solutions (5–25%) and saline mixtures with added glucose, delivered through an acrylic channel aligned to the sensing region, confirm the simulated trends. In vivo, vector network analyzer (VNA) tests were conducted on four human subjects (60–150 mg/dL), comparing single- and dual-finger placements. The FR-4 substrate (${\mathsf{\epsilon }}_{\mathrm{r}}$ = 4.4) provided higher frequency sensitivity (2.005 MHz/(mg/dL)), whereas the Rogers RO3210 substrate (${\mathsf{\epsilon }}_{\mathrm{r}}$ = 10.2) achieved greater amplitude sensitivity (9.35 × 10⁻² dB/(mg/dL)); dual-finger contact outperformed single-finger placement for both substrates. Repeated intra-day VNA measurements yielded narrow 95% confidence intervals on |S₂₁|, with an overall uncertainty of approximately ±0.5 dB across the tested glucose levels. Motivated by the larger |S₂₁| response on Rogers, we adopted amplitude resolution as the primary metric and built a compact prototype using the AD8302-EVALZ with a custom 3D-printed enclosure to enhance measurement precision. In a cohort of 31 participants, capillary blood glucose was obtained using a commercial glucometer, after which two fingers were placed on the sensing region; quadratic voltage-to-glucose calibration yielded R² = 0.980, root–mean–square error (RMSE) = 2.316 mg/dL, overall accuracy = 97.833%, and local sensitivity = 1.099 mg/dL per mV, with anthropometric variables (weight, height, age) showing no meaningful correlation. Clarke Error Grid Analysis placed 100% of paired measurements in Zone A, indicating clinically acceptable agreement with the reference meter. Benchmarking against commercial continuous glucose monitoring systems highlights substrate selection as a dominant lever for amplitude sensitivity and positions the proposed fully non-invasive, consumable-free architecture as a promising route toward portable RF-based glucose monitors, while underscoring the need for larger cohorts, implementation on flexible biocompatible substrates, and future regulatory pathways. Full article

Introduction/Goal: Stress and negative emotions have been shown to exert a substantial impact on cancer patients, affecting their ability to adapt to therapy and the overall effectiveness. Elevated cortisol levels, a stress-induced hormone, have been shown to suppress immune system function, potentially reducing the body’s capacity to combat cancer cells. On the contrary, prolactin, a hormone that stimulates the immune system, has shown potential in this context but requires further study. The objective of this study was to investigate the acute physiological changes that occur during a single Conscious Connected Breathing (CCB) session, as part of a larger investigation on Integrative Breathwork Psychotherapy (IBP), a novel integrative psychosomatic intervention designed to improve psychosomatic and immune status in cancer patients. Methods: The project involved 93 breast cancer patients hospitalized for postoperative radiotherapy who participated in a ten-session IBP program. Fifty-six patients agreed to participate (response rate: 60%). During the experiment, 8 patients were excluded from the analysis. IBP consisted of small group sessions (up to six participants) conducted three times weekly. Each session included 45 min of CCB—defined as rhythmic circular nasal breathing at a depth exceeding resting tidal volume, without breath-holding, performed in a state of mindful acceptance—followed by 15 min of free emotional expression (verbal articulation of emerging feelings and sensations). This was a within-subject pre-post design: physiological measurements were obtained immediately before and 30 min into the tenth session (when participants had achieved technical proficiency) in all participants, who served as their own controls. Outcome measures included: arterialized capillary blood gas parameters (pH, pCO₂, pO₂, ctO₂, COHb, HHb, cH⁺), serum cortisol and prolactin concentrations, and immunoglobulin A (IgA). Results: During the CCB session, blood gas analysis revealed significant changes consistent with mild respiratory alkalosis: decreases in pCO₂ (p = 0.003), pO₂ (p < 0.001), cH⁺ (p < 0.001), ctO₂ (p < 0.001), COHb (p = 0.03), and HHb (p = 0.004), alongside an increase in pH (p < 0.001). Concurrently, prolactin levels increased significantly (p < 0.001), while cortisol (p < 0.001) and IgA (p < 0.001) decreased. Conclusions: This study is the first to analyze acute changes in capillary blood gas parameters and neuroendocrine balance during Conscious Connected Breathing sessions in cancer patients, revealing measurable immunostimulatory and stress-modulatory effects. The observed shift toward respiratory alkalosis, combined with increased prolactin and decreased cortisol, suggests that CCB may facilitate favorable neuroendocrine-immune interactions. These findings support the potential of breathwork as a complementary therapy for cancer patients. Further research is needed to explore underlying mechanisms and assess long-term psychological and immunological impacts. Full article