Third Space Research Articles

PBPK modeling of recombinant factor IX Fc fusion protein (rFIXFc) and rFIX to characterize the binding to type 4 collagen in the extravascular space.

Patients with severe and sometimes moderate hemophilia B are prophylactically treated with factor IX concentrates to prevent bleeding. For some time now, various extended terminal half-life (EHL) recombinant factor IX concentrates are available allowing less frequent administration during prophylaxis in comparison to standard half-life recombinant FIX (rFIX). Especially, recombinant FIX-Fc fusion protein (rFIXFc; Alprolix®) exhibits a rapid distribution phase, potentially due to binding to type IV collagen (Col4) in the extravascular space. Studies suggest that the presence of extravascular rFIXFc is protective against bleeding as without measurable FIX activity in plasma, and no extra bleeding seems to occur. The physiologically based pharmacokinetic (PBPK) model for rFIXFc which we describe in this study, is able to accurately predict the observed concentration-time profiles of rFIXFc in plasma and is able to quantify the binding of rFIXFc to Col4 in the extravascular space after an intravenous dose of 50 IU/kg rFIXFc in a male population. Our model predicts that the total AUC of rFIXFc bound to Col4 in the extravascular space is approximately 19 times higher compared to the AUC of rFIXFc in plasma. This suggests that rFIXFc present in the extravascular compartment may play an important role in achieving hemostasis after rFIXFc administration. Further studies on extravascular distribution of rFIXFc and the distribution profile of other EHL-FIX concentrates are needed to evaluate the predictions of our PBPK model and to investigate its clinical relevance.

Lung Ultrasound as an Adjunct to Pulse Oximetry and Respiratory Symptoms in the Diagnosis of Freediving-Induced Pulmonary Syndrome.

B-lines on lung ultrasound have been found in asymptomatic competitive breath-hold divers, but their significance and time to resolution are not well understood. We sought to investigate the relationship between B-lines, oxygen saturation, and respiratory symptoms after competitive dives to diagnose pulmonary injury. We performed lung ultrasounds before (predive), immediately after (postdive), and within 1 h (follow-up) of a competitive dive. B-lines were counted in each intercostal space in the anterior, lateral, and posterior lung fields, and the highest number of B-lines within a space was recorded for each lung region. At follow-up, each diver's oxygen saturation and respiratory symptoms were recorded. Statistical analysis included the Kruskal-Wallis test, Spearman's correlation, and sensitivity and specificity calculations. Forty-four divers completed 143 individual dives of four different disciplines. The median number of B-lines was 0 (IQR inclusive=0) predive, 1 (IQR=3) postdive, and 0 (IQR=1) at follow-up. There was a significant difference in total B-lines between measurement times (p<0.001). Sensitivity and specificity of hypoxemia, clinically significant B-lines, and both measures in tandem in detecting respiratory symptomatology were 52% and 76%, 24% and 92%, and 24% and 95%, respectively. B-lines are a common phenomenon in competitive breath-hold divers on surfacing and decrease within 1 h, suggesting a physiologic fluid shift. B-lines are negatively correlated with oxygen saturation, indicating that extravascular fluid impairs gas exchange in the lung. Neither hypoxemia nor clinically significant B-lines were found to be reliable indicators for respiratory symptomatology, suggesting that there may be multiple phenotypes of freediving-induced pulmonary syndrome.

PENGARUH KONSENTRASI ASAM KLORIDA (HCl) DAN WAKTU EKSTRAKSI PADA KARAKTERISASI PEKTIN KULIT JERUK BALI (Citrus maxima)

Pectin or pectate compounds are complex polysaccharides with large molecular weights found in the middle lamella or intercellular spaces in higher plant tissues. The main function of pectin is as a thickener and gelling agent. So far, pectin production in Indonesia has not been widely known and developed. Pectin can be obtained from fruit peels, one of which is grapefruit peel. Grapefruit has a fairly high pectin content, around 30%. The purpose of this study was to find out how much pectin content is in grapefruit peels by determining the concentration of hydrochloric acid and the right extraction time to get the best yield and quality of pectin. This study used a randomized block design (RBD) method with two factors, namely the concentration of hydrochloric acid 0.2 N; 0.25 N and 0.3 N and extraction times of 60, 90 and 120 minutes with three repetitions. The observations made were yield pectin, water content, ash content, equivalent weight, methoxyl content, galacturonic acid and degree of esterification. The data obtained based on the research results were analyzed statistically with variance (α = 0.05) and continued with the Duncan Multiple Range Test (DMRT). The results showed that the concentration of hydrochloric acid 0.3 N and extraction time of 120 minutes produced the best pectin with yield 13.57%, moisture content 8.27%, ash content 7.53%, methoxyl content 6.79%, galacturonic content 261 .65%, the degree of esterification is 14.82% and it can be concluded that the test results for the characteristics of the pectin produced meet the established standards of the International Pectin Producers Association (IPPA).

Patent urachus with subcutaneous communication and ventral abdominal swelling in a domestic short‐hair cat

AbstractA 3‐month‐old, male, entire, domestic shorthair kitten underwent investigations for stranguria and haematuria, and was diagnosed with a urinary tract infection secondary to a suspected extramural vesicourachal diverticulum. Lower urinary tract signs resolved with a 14‐day course of amoxicillin clavulanate. Three months later, the kitten re‐presented for investigation of acute onset ventral abdominal discomfort and bruising. On presentation, clinical examination revealed omphalitis and subcutaneous bruising, with no evidence of an umbilical stoma. Ultrasonography demonstrated a patent urachus communicating with the subcutaneous tissue space, resulting in accumulation of urine at the level of the umbilicus. A ventral midline coeliotomy was performed to allow resection of the urachal remnant, including a partial cystectomy. The cat was urinating normally within 10 hours postoperatively, and the wound healed without complication. No postoperative complications or recurrent lower urinary tract signs were reported at follow‐up (312 days).

Experiment on the vortex-induced vibration of an S-shaped flexible riser coupled with an oscillating platform

This paper reports the experimental results of the vortex-induced vibration (VIV) of an S-shaped flexible riser hanged underneath a two-degree-of-freedom (2-DOF) oscillating cylindrical platform. A buoyancy module of approximately triple the riser diameter was mounted on the one-third of the riser length measured from its base to produce the S-shaped configuration. The VIV response of the flexible riser filled with two typical fluid media, including water and helium, was tested in the depth-averaged reduced velocity (U¯r) range of 9.32–26.41. The experimental results indicate that the change of internal fluid medium alters the spatial distribution of dominant frequency and excited modal order. The mode competition is enhanced when the internal fluid shifts from water to helium, and the critical U¯r for mode transition becomes higher. Based on the coincidence of dominant frequency, four types of coupling response are identified, and two characteristic lengths are quantified. The dominant role of the vibration system is determined by the occurrence time percentages of coupling lengths and dominant frequencies. The vibration of water-filled riser is dominated by itself, and the influence of buoyancy module is negligible. In contrast, the in-plane response of helium-filled riser is significantly affected by the buoyancy module, and the influence is amplified with the increase in U¯r.

Abstract P223: Impact Of Dynamic Or Static Training On Flow-Mediated Dilatation Following Prolonged Head-Down Tilt Bedrest

Cardiovascular deconditioning, cephalad fluid shifts, and altered sympathetic activity in weightlessness may elicit changes in vascular structure and function akin to vascular ageing. Head-down tilt bedrest is an established terrestrial model for weightlessness and elicits similar cardiovascular responses. We hypothesized that 30 days head-down tilt bedrest (HDTBR) worsens flow mediated dilation (FMD), a non-invasive endothelial function marker, and that daily orthostatic stimuli or physical exercise attenuates the response. Fourty-seven healthy individuals (20 women, age 35±9 years, BMI 23.7±2.6 kg/m 2 ) were assigned to 30 days of strict HDTBR and divided into four groups: Daily 6 hours of upright sitting (positive control, n=11); 6 hours of -25 mmHg lower body negative pressure (n=12); 60 minutes of supine cycling followed by 6 hours of thigh cuff venous occlusion 6 days per week (n=12), or no countermeasure (negative control, n=12). We measured upper arm blood pressure and heart rate 5 days before and immediately after bedrest. We assessed plasma volume by carbon monoxide-rebreathing 2 days before and on day 28 of bedrest. We determined FMD of the brachial artery 5 days before, on day 28 of bedrest, and after 13-day recovery. We collected blood samples to measure pro- and anti-inflammatory cytokines. Heart rate was elevated after bedrest (p&lt;0.0001) but remained constant in seated and cycling groups (seated MD 5±2 /min, cycling MD 5±2, p=0.0051). Systolic blood pressure increased in all groups (MD 4±1 mmHg, p=0.0004). Diastolic blood pressure was higher post-bedrest in the control group (MD 8±2 mmHg, p=0.0002) but remained constant in the countermeasure groups. Plasma volume was reduced after bed rest (MD -400±37 ml, p&lt;0.0001) but maintained in the cycling group (MD 147±72 ml, p=0.0001). FMD did not differ between groups, but was higher at bedrest (MD 1.9±0.8 %, p=0.0481), whereas recovery values did not differ from baseline. Resting brachial artery diameter tended to be higher at bedrest (p=0.0876). Cytokines revealed no clinically relevant inflammatory response. Head-down tilt bedrest-induced cardiovascular deconditioning, which was not completely abolished by any countermeasure, paradoxically increased flow-mediated brachial vasodilation. Additional cardiovascular risk factors may be required to express endothelial dysfunction in the face of reduced physical activity.

Sequential recruitment of body fluid spaces for increasing volumes of crystalloid fluid.

The interstitial space harbours two fluid compartments linked serially to the plasma. This study explores conditions that lead to fluid accumulation in the most secluded compartment, termed the "third space". Retrospective data was collected from 326 experiments in which intravenous crystalloid fluid was administered to conscious volunteers as well as a small group of anaesthetized patients. The urinary excretion and plasma dilution derived from haemoglobin served as input variables in nine population volume kinetic analyses representing subtly different settings. An infusion of 250-500mL of Ringer's solution expanded only the central fluid space (plasma), whereas the infusion of 500-1,000mL extended into a rapidly exchanging interstitial fluid space. When more than 1L was infused over 30min, it was distributed across plasma and both interstitial fluid compartments. The remote space, characterized by slow turnover, abruptly accommodated fluid upon accumulation of 700-800mL in the rapidly exchanging space, equivalent to an 11%-13% volume increase. However, larger expansion was necessary to trigger this event in a perioperative setting. The plasma half-life of crystalloid fluid was 25 times longer when 2,000-2,700mL expanded all three fluid compartments compared to when only 250-500mL expanded the central space (14h versus 30min). As the volume of crystalloid fluid increases, it apparently occupies a larger proportion of the interstitial space. When more than 1L is administered at a high rate, there is expansion of a remote "third space", which considerably extends the intravascular half-life.

Non-immune hydrops fetalis is associated with bi-allelic pathogenic variants in the MYB Binding Protein 1a (MYBBP1A) gene.

Non-immune hydrops fetalis (NIHF) is a rare entity characterized by excessive accumulation of fluid within the fetal extravascular compartments and body cavities. Here we present two intrauterine fetal demises with NIHF presenting with oligohydramnios, cystic hygroma, pleural effusion, and generalized hydrops with predominance of subcutaneous edema. The fetuses also presented with ascites, severe and precocious IUGR and skeletal anomalies. Whole exome sequencing was applied in order to screen for a possible genetic cause. The results identified biallelic variants in MYBBP1A in both fetuses. A previous report described another case with a similar phenotype having compound heterozygous variants in the same gene. The protein encoded by MYBBP1A is involved in several cellular processes including the synthesis of ribosomal DNA, the response to nucleolar stress, and tumor suppression. Our functional protein analysis through immunohistochemistry indicates that MYBBP1A is a gene expressed during fetal stages. Altogether, we concluded that MYBBP1A is associated with the development of hydrops fetalis. More cases and further studies are necessary to understand the role of this gene and the mechanism associated with NIHF.

The effect of changes in intra-compartmental bioimpedance measurements with early intra-dialytic hypotension during haemodialysis.

Intra-dialytic hypotension (IDH) remains the commonest problem associated with routine haemodialysis treatments. Fluid shifts from intracellular(ICW) and extracellular(ECW) compartments to refill plasma volume during haemodialysis with ultrafiltration. We studied the effect of relative changes in ICW and ECW indifferent body segments using multifrequency segmental bioimpedance during haemodialysis and IDH episodes. Of 42 haemodialysis patients,16 patients (38.1%) developed IDH within the first hour of dialysis. Patients with and without early IDH were well-matched for demographics and starting bioimpedance measurements. However, after 60 min, the relative change in in ECW/ICW ratio between the non-fistula arm and leg was significantly different for the early IDH group median -1.07 (-3.33 to 0.8) versus 0.61 (-0.78 to 1.8), p < 0.05, whereas there no differences in ultrafiltration rate, relative blood volume monitoring or on-line clearance. Monitoring serial changes in fluid status in different body compartments with bioimpedance may potentially prevent IDH in the future.

Linking disease activity with optical coherence tomography angiography in neovascular age related macular degeneration using artificial intelligence

To investigate quantitative associations between AI-assessed disease activity and optical coherence tomography angiography (OCTA)-derived parameters in patients with neovascular age-related macular degeneration (nAMD) undergoing anti-VEGF therapy. OCTA and SD-OCT images obtained from multicenter, randomized study data were evaluated. A deep learning algorithm (RetInSight) was used to detect and quantify macular fluid on SD-OCT. Mixed effects models were applied to evaluate correlations between fluid volumes, macular neovascularization (MNV)-type and OCTA-derived MNV parameters; lesion size (LS) and vessel area (NVA). 230 patients were included. A significant positive correlation was observed between SRF and NVA (estimate = 199.8 nl/mm2, p = 0.023), while a non-significant but negative correlation was found between SRF and LS (estimate = − 71.3 nl/mm2, p = 0.126). The presence of Type I and Type II MNV was associated with significantly less intraretinal fluid (IRF) compared to Type III MNV (estimate type I:− 52.1 nl, p = 0.019; estimate type II:− 51.7 nl, p = 0.021). A significant correlation was observed between pigment epithelial detachment (PED) and the interaction between NVA and LS (estimate:28.97 nl/mm2; p = 0.012). Residual IRF at week 12 significantly correlated to baseline NVA (estimate:38.1 nl/mm2; p = 0.015) and LS (estimate:− 22.6 nl/mm2; p = 0.012). Fluid in different compartments demonstrated disparate associations with MNV OCTA features. While IRF at baseline was most pronounced in type III MNV, residual IRF was driven by neovascular MNV characteristics. Greater NVA in proportion to LS was associated with higher amounts of SRF and PED. The correlation between these parameters may represent MNV maturation and can be used as a biomarker for resolution of disease activity. AI-based OCT analysis allows for a deeper understanding of neovascular disease in AMD and the potential to adjust therapeutic strategies to optimize outcomes through precision medicine.

Closed Loop Ultrafiltration Feedback Control in Hemodialysis: A Narrative Review.

While life-sustaining, hemodialysis is a non-physiological treatment modality that exerts stress on the patient, primarily due to fluid shifts during ultrafiltration. Automated feedback control systems, integrated with sensors that continuously monitor bio-signals such as blood volume, can adjust hemodialysis treatment parameters, e.g., ultrafiltration rate, in real-time. These systems hold promise to mitigate hemodynamic stress, prevent intradialytic hypotension, and improve the removal of water and electrolytes in chronic hemodialysis patients. However, robust evidence supporting their clinical application remains limited. Based on an extensive literature research, we assess feedback-controlled ultrafiltration systems that have emerged over the past three decades in comparison to conventional hemodialysis treatment. We identified 28 clinical studies. Closed loop ultrafiltration control demonstrated effectiveness in 23 of them. No adverse effects of closed loop ultrafiltration control were reported across all trials. Closed loop ultrafiltration control represents an important advancement towards more physiological hemodialysis. Its development is driven by innovations in real-time bio-signals monitoring, advancement in control theory, and artificial intelligence. We expect these innovations will lead to the prevalent adoption of ultrafiltration control in the future, provided its clinical value is substantiated in adequately randomized controlled trials.

Angiotensin II as a Vasopressor for Perioperative Hypotension in Solid Organ Transplant.

During the perioperative period of transplantation, patients experience hypotension secondary to the side effects of anesthesia, surgical stress, inflammatory triggering, and intraoperative fluid shifts, among others causes. Vasopressor support, in this context, must reverse systemic hypotension, but ideally, the agents used should benefit allograft function and avoid the adverse events commonly seen after transplantation. Traditional therapies to reverse hypotension include catecholamine vasopressors (norepinephrine, epinephrine, dopamine, and phenylephrine), but their utility is limited when considering allograft complications and adverse events such as arrhythmias with agents with beta-adrenergic properties. Synthetic angiotensin II (AT2S-[Giapreza]) is a novel vasopressor indicated for distributive shock with a unique mechanism of action as an angiotensin receptor agonist restoring balance to an often-disrupted renin angiotensin aldosterone system. Additionally, AT2S provides a balanced afferent and efferent arteriole vasoconstriction at the level of the kidney and could avoid the arrhythmic complications of a beta-adrenergic agonist. While the data, to date, are limited, AT2S has demonstrated safety in case reports, pilot studies, and small series in the kidney, liver, heart, and lung transplant populations. There are physiologic and hemodynamic reasons why AT2S could be a more utilized agent in these populations, but further investigation is warranted.

Evaluation of cerebrospinal fluid (CSF) and interstitial fluid (ISF) mouse proteomes for the validation and description of Alzheimer’s disease biomarkers

BackgroundMass spectrometry (MS)-based cerebrospinal fluid (CSF) proteomics is an important method for discovering biomarkers of neurodegenerative diseases. CSF serves as a reservoir for interstitial fluid (ISF), and extensive communication between the two fluid compartments helps to remove waste products from the brain. New methodWe performed proteomic analyses of both CSF and ISF fluid compartments using intracerebral microdialysis to validate and detect novel biomarkers of Alzheimer's disease (AD) in APPtg and C57Bl/6J control mice. ResultsWe identified up to 625 proteins in ISF and 4483 proteins in CSF samples. By comparing the biofluid profiles of APPtg and C57Bl/6J mice, we detected 37 and 108 significantly up- and downregulated candidates, respectively. In ISF, 7 highly regulated proteins, such as Gfap, Aldh1l1, Gstm1, and Txn, have already been implicated in AD progression, whereas in CSF, 9 out of 14 highly regulated proteins, such as Apba2, Syt12, Pgs1 and Vsnl1, have also been validated to be involved in AD pathogenesis. In addition, we also detected new interesting regulated proteins related to the control of synapses and neurotransmission (Kcna2, Cacng3, and Clcn6) whose roles as AD biomarkers should be further investigated. Comparison with existing methodsThis newly established combined protocol provides better insight into the mutual communication between ISF and CSF as an analysis of tissue or CSF compartments alone. ConclusionsThe use of multiple fluid compartments, ISF and CSF, for the detection of their biological communication enables better detection of new promising AD biomarkers.

Cardiovascular effects of long-duration space flight.

Early studies exploring the physiological effects of space travel have indicated the body's capacity for reversible adaptation. However, the impact of long-duration spaceflight, exceeding 6 months, presents more intricate challenges. Extended exposure to microgravity and radiation profoundly affects the CV system. Notable phenomena include fluid shifts toward the head and modified arterial pressure. These changes disrupt blood pressure regulation and elevate cardiac output. Additionally, the loss of venous compression leads to a reduction in central venous pressure. The displacement of fluid from the vascular system to the interstitium, driven by baroreceptor stimulation, results in a 10%-15% decline in plasma volume. Intriguingly, despite potential increases in cardiac workload, cardiac muscle atrophy and perplexing variations in hematocrit levels have been observed. The mechanism underlying atrophy appears to involve a shift in protein synthesis from the endoplasmic reticulum to the mitochondria via mortalin-mediated mechanisms. Instances of arrhythmias have been recurrently documented, although generally nonlethal, in both Russian and American space missions. Long-duration spaceflight has been associated with the prolongation of the QT interval, particularly in extended missions. Exposure of the heart to the proton and heavy ion radiation pervasive in deep space contributes to coronary artery degeneration, augmented aortic stiffness, and carotid intima thickening through collagen-mediated processes. Moreover, it accelerates the onset of atherosclerosis and triggers proinflammatory responses. Upon reentry, astronauts frequently experience orthostatic intolerance and altered sympathetic responses, which bear potential hazards in scenarios requiring rapid mobilization or evacuation. Consequently, careful monitoring of these cardiac risks is imperative for forthcoming missions. While early studies illuminate the adaptability of the body to space travel's challenges, the intricacies of long-duration missions and their effects on the CV system necessitate continued investigation and vigilance to ensure astronaut health and mission success.

New anatomical findings in the mandibular body region: Two parts that make up bucco-mandibular space.

Soft tissue spaces not only enable gliding by contraction of the facial muscles, but they also cause drooping of the superficial fat due to gravity in the upright position. This study was performed to clarify the structures around the bucco-mandibular space (BMS) and to apply this anatomical knowledge to clinical practice. Four sides of the face were dissected using a conventional gross anatomical dissection technique, and 10 sides (5 horizontal and 5 frontal sections) of the removed semi-facial soft tissue were dissected using the stretched tissue dissection (STD) method. Histological examination of the mandible was performed on two sides to confirm the findings of conventional gross anatomical dissection and STD. In all cases, both gross dissection and STD revealed that the BMS was composed of two parts. The superficial part was filled with adipose tissue containing nerves and vessels, including the marginal mandibular branch of the facial nerve, facial artery, facial vein, and mental nerve. We named this part the adipo-neuromandibular part. By contrast, the deep part was separated from the adipo-neurovascular part by facial deep fascia and composed of loose connective tissue. We named this deep part the loose connective tissue part. The STD method enabled us to obtain detailed anatomical findings of the mandibular region and elucidate two parts of the BMS in which the neurovasculature is distributed. We believe that these findings provide new insights into facial anatomy by resolving existing anatomical uncertainties and will contribute to safer surgical treatment in the facial region.

Tangential flow filtration facilitated fractionation of polymerized human serum albumin: Insights into the effects of molecular size on biophysical properties.

Human serum albumin (HSA) is currently used as a plasma expander (PE) to increase blood volume during hypovolemic conditions, such as blood loss. However, its effectiveness is suboptimal in septic shock and burn patients due to their enhanced endothelial permeability, resulting in HSA extravasation into the tissue space leading to edema, and deposition of toxic HSA-bound metabolites. Hence, to expand HSA's applicability toward treating patients with compromised endothelial permeability, HSA has been previously polymerized to increase its molecular size thus compartmentalizing the polymerized HSA (PolyHSA) molecules in the vascular space. Previous studies bracketed PolyHSA between 100 kDa and 0.2 μm. In this research, PolyHSA was synthesized at two cross-link densities 43:1 and 60:1 (i.e., molar ratios of glutaraldehyde to HSA) and subsequently fractionated via tangential flow filtration (TFF) into two narrower brackets: bracket A (500 kDa and 0.2 μm) and bracket B (50-500 kDa). PolyHSA within the same size bracket at different cross-link densities exhibited similar solution viscosity, zeta potential, and osmolality but differed in hydrodynamic diameter. At the same cross-link density, the PolyHSA A bracket showed higher viscosity, lowered zeta potential, and a larger hydrodynamic diameter compared with the PolyHSA B bracket while maintaining osmolality. Interestingly, PolyHSA 43:1 B, PolyHSA 60:1 A, and PolyHSA 60:1 B brackets exhibited colloid osmotic pressure similar to HSA, indicating their potential to serve as PEs.

Simulated Microgravity Alters Gene Regulation Linked to Immunity and Cardiovascular Disease.

Microgravity exposure induces a cephalad fluid shift and an overall reduction in physical activity levels which can lead to cardiovascular deconditioning in the absence of countermeasures. Future spaceflight missions will expose crew to extended periods of microgravity among other stressors, the effects of which on cardiovascular health are not fully known. In this study, we determined cardiac responses to extended microgravity exposure using the rat hindlimb unloading (HU) model. We hypothesized that exposure to prolonged simulated microgravity and subsequent recovery would lead to increased oxidative damage and altered expression of genes involved in the oxidative response. To test this hypothesis, we examined hearts of male (three and nine months of age) and female (3 months of age) Long-Evans rats that underwent HU for various durations up to 90 days and reambulated up to 90 days post-HU. Results indicate sex-dependent changes in oxidative damage marker 8-hydroxydeoxyguanosine (8-OHdG) and antioxidant gene expression in left ventricular tissue. Three-month-old females displayed elevated 8-OHdG levels after 14 days of HU while age-matched males did not. In nine-month-old males, there were no differences in 8-OHdG levels between HU and normally loaded control males at any of the timepoints tested following HU. RNAseq analysis of left ventricular tissue from nine-month-old males after 14 days of HU revealed upregulation of pathways involved in pro-inflammatory signaling, immune cell activation and differential expression of genes associated with cardiovascular disease progression. Taken together, these findings provide a rationale for targeting antioxidant and immune pathways and that sex differences should be taken into account in the development of countermeasures to maintain cardiovascular health in space.

Spatial omics technologies for understanding molecular status associated with cancer progression.

Cancer cells are generally exposed to numerous extrinsic stimulations in the tumor microenvironment. In this environment, cancer cells change their expression profiles to fight against circumstantial stresses, allowing their progression in the challenging tissue space. Technological advancements of spatial omics have had substantial influence on cancer genomics. This technical progress, especially that occurring in the spatial transcriptome, has been drastic and rapid. Here, we describe the latest spatial analytical technologies that have allowed omics feature characterization to retain their spatial and histopathological information in cancer tissues. Several spatial omics platforms have been launched, and the latest platforms finally attained single-cell level or even higher subcellular level resolution. We discuss several key papers elucidating the initial utility of the spatial analysis. In fact, spatial transcriptome analyses reveal comprehensive omics characteristics not only in cancer cells but also their surrounding cells, such as tumor infiltrating immune cells and cancer-associated fibroblasts. We also introduce several spatial omics platforms. We describe our own attempts to investigate molecular events associated with cancer progression. Furthermore, we discuss the next challenges in analyzing the multiomics status of cells, including their morphology and location. These novel technologies, in conjunction with spatial transcriptome analysis and, more importantly, with histopathology, will elucidate even novel key aspects of the intratumor heterogeneity of cancers. Such enhanced knowledge is expected to open a new path for overcoming therapeutic resistance and eventually to precisely stratify patients.

Comparative analysis of the effectiveness of bone matrix purification protocols

Background: This article describes the protocol for the purification of xenogenic bone matrix tested by a team of authors in the article «Determining the effectiveness of a xenogeneic bone matrix decellularization protocol in in vitro and in vivo studies» (the test results were described in the journal N.N. Priorov Journal of Traumatology and Orthopedics. 2023;30(4):431–443, doi: https://doi.org/10.17816/vto622849). AIM: To conduct a comparative analysis of methods of physical and chemical purification of xenogeneic spongy bone tissue by tomographic and morphological studies. MATERIALS AND METHODS: Xenogenic bovine femoral spongiosa tissue was fragmented to the size of 10×10×10 mm and treated with water, hypertonic, hypotonic, hypotonic solutions, and 3% or 6% hydrogen peroxide solution in various combinations. Deep secondary purification with organic solvents or supercritical fluid extraction was then applied, followed by 1H NMR to determine traces of reagents. The efficiency of the optimal protocol was determined by histologic and tomographic studies with calculation of the purification factor by densitometric indices. RESULTS: In accordance with the purification coefficient calculated by densitometric indicators, the intertrabecular space of bone tissue after exposure to flowing water and hypo- and hypertonic solutions followed by cleaning with a 3% H2O2 solution is not sufficiently purified; histological analysis showed the presence of 0 to 60% osteocytes for different cleaning protocols. When replaced with a 6% H2O2 solution, the purification coefficient was higher, but bone destruction was observed. Additional deep purification allows a high purification rate while preserving the structure, but when organic solvents are used, their traces are detected in the matrix; therefore, the use of supercritical fluid extraction is more effective. CONCLUSION: The sequential use of flowing water, 0.5% NaCl solution, 3% H2O2 solution followed by sc-CO2 treatment is an effective protocol for the purification of xenogeneic spongy bone tissue.

Spatial heterogeneity and functional zonation of living tissues and organs in situ.

In most organs, resources such as nutrients, oxygen and physiologically active substances are unevenly supplied within the tissue spaces. Consequently, different tissue functions are exhibited in each space. This spatial heterogeneity of tissue environments arises depending on the spatial arrangement of nutrient vessels and functional vessels, leading to continuous changes in the metabolic states and functions of various cell types from regions proximal to these vessels to distant regions. This phenomenon is referred to as 'zonation'. Traditional analytical methods have made it difficult to investigate this zonation in detail. However, recent advancements in intravital imaging, spatial transcriptomics and single-cell transcriptomics technologies have facilitated the discovery of 'zones' in various organs and elucidated their physiological roles. Here, we outline the spatial differences in the immune system within each zone of organs. This information provides a deeper understanding of organs' immune systems.