Nuclear magnetic resonance footprint of Wharton Jelly mesenchymal stem cells death mechanisms and distinctive in‐cell biophysical properties in vitro

Assessment of renal pathophysiological processes and protective effect of quercetin on contrast-induced acute kidney injury in type 1 diabetic mice using diffusion tensor imaging

Purpose: To investigate the renal pathophysiological processes and protective effect of quercetin on contrast-induced acute kidney injury (CI-AKI) in mice with type 1 diabetic mellitus(DM) using diffusion tensor imaging(DTI).Methods: Mice with DM were divided into two groups. In the diabetic + contrast medium(DCA) group, the changes of the mice kidneys were monitored at 1, 24, 48, and 72 h after the injection of iodixanol(4gI/kg). The mice in the diabetic + contrast medium + quercetin(DCA + QE) group were orally given different concentrations of quercetin for seven days before injection of iodixanol. In vitro experiments, renal tubular epithelial (HK-2) cells exposed to high glucose conditions were treated with various quercetin concentrations before treatment with iodixanol(250 mgI/mL).Results: DTI-derived mean diffusivity(MD) and fractional anisotropy(FA) values can be used to evaluate CI-AKI effectively. Quercetin significantly increased the expression of Sirt 1 and reduced oxidative stress by increasing Nrf 2/HO-1/SOD1. The antiapoptotic effect of quercetin on CI-AKI was revealed by decreasing proteins level and by reducing the number of apoptosis-positive cells. In addition, flow cytometry indicated quercetin-mediated inhibition of M1 macrophage polarization in the CI-AKI.Conclusions: DTI will be an effective noninvasive tool in diagnosing CI-AKI. Quercetin attenuates CI-AKI on the basis of DM through anti-oxidative stress, apoptosis, and inflammation.

Study of the collagen tissue nanostructure by analyzing the echo decay obtained using the MRI technique

The multicomponent relaxation observed in nuclear magnetic resonance experiments in biological tissues makes it difficult to establish a correlation between specific relaxation times and tissue structural parameters. The analysis of a nanostructure (the characteristic size of 10-1000 nm) is usually based on formulas for relaxation times which depend on structural parameters at the atomic or molecular levels in the size range of 0.1-5 nm. We have recently developed an analysis method in which relaxation times' anisotropy in a sample is explicitly related to its structure of nanocavities containing a liquid or gas. However, the method is based on the analysis of experimental data on the anisotropy of relaxation times obtained by using the standard NMR technique and rotating the sample relative to a magnetic field and requires a series of experiments. In the present study, to address this challenge, we develop a new method of analysis of a multi-exponential magnetic resonance signal that does not require determining relaxation times and eliminates the sample rotation and the necessity of a series of experiments. Using the magnetic resonance imaging (MRI) technique, the total signal from the whole sample was obtained as a sum of the signals (echo decays) from all voxels. In contrast to previous research, the volumes of nanocavities and their angular distribution can be obtained by analyzing a single total signal for the entire cartilage. In addition, within the framework of this approach, it is possible to identify the reason for the multicomponent nature of relaxation. The proposed method for analyzing a single multi-exponential signal (transverse relaxation) was implemented on cartilage. Using the signal, three anatomical zones of cartilage were studied, revealing significant structural differences between them. The proposed method not only avoids the need for sample rotation but also enables repeated application of layer-by-layer magnetic resonance imaging with micron resolution. The study results allow us to suggest that water molecules contributing to the echo decay are more likely located in nanocavities formed by the fibrillar structure rather than inside the fibrils.

Diffusion tensor imaging metrics as natural markers of multiple sclerosis-induced brain disorders with a low Expanded Disability Status Scale score

Non-invasive and effective differentiation along with determining the degree of deviations compared to the healthy cohort is important in the case of various brain disorders, including multiple sclerosis (MS). Evaluation of the effectiveness of diffusion tensor metrics (DTM) in 3T DTI for recording MS-related deviations was performed using a time-acceptable MRI protocol with unique comprehensive detection of systematic errors related to spatial heterogeneity of magnetic field gradients. In a clinical study, DTMs were acquired in segmented regions of interest (ROIs) for 50 randomly selected healthy controls (HC) and 50 multiple sclerosis patients. Identical phantom imaging was performed for each clinical measurement to estimate and remove the influence of systematic errors using the b-matrix spatial distribution in the DTI (BSD-DTI) technique. In the absence of statistically significant differences due to age in healthy volunteers and patients with multiple sclerosis, the existence of significant differences between groups was proven using DTM. Moreover, a statistically significant impact of spatial systematic errors occurs for all ROIs and DTMs in the phantom and for approximately 90 % in the HC and MS groups. In the case of a single patient measurement, this appears for all the examined ROIs and DTMs. The obtained DTMs effectively discriminate healthy volunteers from multiple sclerosis patients with a low mean score on the Expanded Disability Status Scale. The magnitude of the group differences is typically significant, with an effect size of approximately 0.5, and similar in both the standard approach and after elimination of systematic errors. Differences were also observed between metrics obtained using these two approaches. Despite a small alterations in mean DTMs values for groups and ROIs (1-3 %), these differences were characterized by a huge effect (effect size ∼0.8 or more). These findings indicate the importance of determining the spatial distribution of systematic errors specific to each MR scanner and DTI acquisition protocol in order to assess their impact on DTM in the ROIs examined. This is crucial to establish accurate DTM values for both individual patients and mean values for a healthy population as a reference. This approach allows for an initial reliable diagnosis based on DTI metrics.

Mesenchymal stem cell-derived extracellular vesicles for metabolic syndrome therapy: Assessing efficacy with nuclear magnetic resonance spectroscopy

Metabolic syndrome (MetS) represents a cluster of metabolic abnormalities. The prevalence of MetS has surged, transforming it into a pressing public health concern that could potentially affect around 20%-25% of the global population. As MetS continues its ascent, diverse interventions, pharmacological, nonpharmacological and combined have been deployed. Yet, a comprehensive remedy that fully eradicates MetS symptoms remains elusive, compounded by the risks of polypharmacy's emergence. Acknowledging the imperative to grasp MetS's intricate pathologies, deeper insights for future research and therapy optimisation become paramount. Conventional treatments often target specific syndrome elements. However, a novel approach emerges in mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) therapy, promising a holistic shift. MSC-EVs, tiny membranous vesicles secreted by mesenchymal stem cells, have garnered immense attention for their multifaceted bioactivity and regenerative potential. Their ability to modulate inflammation, enhance tissue repair and regulate metabolic pathways has prompted researchers to explore their therapeutic application in MetS. This review primarily aims to provide an overview of how MSC-EVs therapy can improve metabolic parameters in subjects with MetS disease and also introduce the usefulness of NMR spectroscopy in assessing the efficacy of MSC-EVs therapy for treating MetS.

Low-field time-domain NMR relaxometry for studying polymer hydration and mobilization in sodium alginate matrix tablets

Sodium alginate is used in various industries, including food, pharmaceutical, and agriculture. Matrix systems, e.g., tablets, and granules, are macro samples with incorporated active substances. During hydration, they are neither equilibrated nor homogenous. Phenomena occurring during hydration of such systems are complex, determine their functional properties and hence require multimodal analysis. Still, there's a lack of comprehensive view. The study aimed to obtain unique characteristics of the sodium alginate matrix during hydration, particularly considering polymer mobilization phenomena using low-field time-domain NMR relaxometry in H₂O and D₂O. An increase in total signal during 4 h of hydration in D₂O of ca. 30 μV resulted from polymer/water mobilization. Modes in T₁-T₂ maps and changes in their amplitudes reflected physicochemical state of the polymer/water system: e.g. air-dry polymer mode (T₁/T₂ ~ 600) and two mobilized polymer/water modes (at T₁/T₂ ~ 40 and T₁/T₂ ~ 20). The study describes the approach to evaluating the hydration of the sodium alginate matrix in terms of the temporal evolution of proton pools: those existing in the matrix before hydration and those entering the matrix from the bulk water. It provides data complementary to spatially resolved methods like MRI and microCT.

Insights into the Small Molecule Targeting of Biologically Relevant G-Quadruplexes: An Overview of NMR and Crystal Structures

G-quadruplexes turned out to be important targets for the development of novel targeted anticancer/antiviral therapies. More than 3000 G-quadruplex small-molecule ligands have been described, with most of them exerting anticancer/antiviral activity by inducing telomeric damage and/or altering oncogene or viral gene expression in cancer cells and viruses, respectively. For some ligands, in-depth NMR and/or crystallographic studies were performed, providing detailed knowledge on their interactions with diverse G-quadruplex targets. Here, the PDB-deposited NMR and crystal structures of the complexes between telomeric, oncogenic or viral G-quadruplexes and small-molecule ligands, of both organic and metal-organic nature, have been summarized and described based on the G-quadruplex target, from telomeric DNA and RNA G-quadruplexes to DNA oncogenic G-quadruplexes, and finally to RNA viral G-quadruplexes. An overview of the structural details of these complexes is here provided to guide the design of novel ligands targeting more efficiently and selectively cancer- and virus-related G-quadruplex structures.