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Scientific Reports Jun 2024The maintenance of intestinal integrity and barrier function under conditions of restricted oxygen availability is crucial to avoid bacterial translocation and local...
The maintenance of intestinal integrity and barrier function under conditions of restricted oxygen availability is crucial to avoid bacterial translocation and local inflammation. Both lead to secondary diseases after hemorrhagic shock and might increase morbidity and mortality after surviving the initial event. Monitoring of the intestinal integrity especially in the early course of critical illness remains challenging. Since microcirculation and mitochondrial respiration are main components of the terminal stretch of tissue oxygenation, the evaluation of microcirculatory and mitochondrial variables could identify tissues at risk during hypoxic challenges, indicate an increase of intestinal injury, and improve our understanding of regional pathophysiology during acute hemorrhage. Furthermore, improving intestinal microcirculation or mitochondrial respiration, e.g. by remote ischemic preconditioning (RIPC) that was reported to exert a sufficient tissue protection in various tissues and was linked to mediators with vasoactive properties could maintain intestinal integrity. In this study, postcapillary oxygen saturation (µHbO), microvascular flow index (MFI) and plasmatic D-lactate concentration revealed to be early markers of intestinal injury in a rodent model of experimental hemorrhagic shock. Mitochondrial function was not impaired in this experimental model of acute hemorrhage. Remote ischemic preconditioning (RIPC) failed to improve intestinal microcirculation and intestinal damage during hemorrhagic shock.
Topics: Animals; Ischemic Preconditioning; Rats; Shock, Hemorrhagic; Microcirculation; Intestines; Male; Biomarkers; Disease Models, Animal; Mitochondria; Intestinal Mucosa; Lactic Acid
PubMed: 38839819
DOI: 10.1038/s41598-024-63293-4 -
Physiological Reports Jun 2024Superficial, systemic microcirculations, distinct from the pulmonary circulation, supply the mucosae of human nasal and conducting airways. Non-injurious, inflammatory... (Review)
Review
Superficial, systemic microcirculations, distinct from the pulmonary circulation, supply the mucosae of human nasal and conducting airways. Non-injurious, inflammatory challenges of the airway mucosa cause extravasation without overt mucosal oedema. Instead, likely reflecting minimal increases in basolateral hydrostatic pressure, circulating proteins/peptides of all sizes are transmitted paracellularly across the juxtaposed epithelial barrier. Thus, small volumes of extravasated, unfiltered bulk plasma appear on the mucosal surface at nasal and bronchial sites of challenge. Importantly, the plasma-exuding mucosa maintains barrier integrity against penetrability of inhaled molecules. Thus, one-way epithelial penetrability, strict localization, and well-controlled magnitude and duration are basic characteristics of the plasma exudation response in human intact airways. In vivo experiments in human-like airways demonstrate that local plasma exudation is also induced by non-sanguineous removal of epithelium over an intact basement membrane. This humoral response results in a protective, repair-promoting barrier kept together by a fibrin-fibronectin net. Plasma exudation stops once the provisional barrier is substituted by a new cellular cover consisting of speedily migrating repair cells, which may emanate from all types of epithelial cells bordering the denuded patch. Exuded plasma on the surface of human airways reflects physiological microvascular-epithelial cooperation in first line mucosal defense at sites of intact and regenerating epithelium.
Topics: Humans; Blood Proteins; Regeneration; Respiratory Mucosa
PubMed: 38837627
DOI: 10.14814/phy2.16096 -
Journal of Cerebral Blood Flow and... Jun 2024Endothelial blood-brain barrier (BBB) dysfunction is critical in the pathophysiology of brain injury. Rho-associated protein kinase (ROCK) activation disrupts BBB...
Endothelial blood-brain barrier (BBB) dysfunction is critical in the pathophysiology of brain injury. Rho-associated protein kinase (ROCK) activation disrupts BBB integrity in the injured brain. We aimed to test the efficacy of a novel ROCK2 inhibitor in preserving the BBB after acute brain injury. We characterized the molecular structure and pharmacodynamic and pharmacokinetic properties of a novel selective ROCK2 inhibitor, NRL-1049, and its first metabolite, 1-hydroxy-NRL-1049 (referred to as NRL-2017 hereon) and tested the efficacy of NRL-1049 on the BBB integrity in rodent models of acute brain injury. Our data show that NRL-1049 and NRL-2017 both inhibit ROCK activity and are 44-fold and 17-fold more selective towards ROCK2 than ROCK1, respectively. When tested in a mouse model of cortical cryoinjury, NRL-1049 significantly attenuated the increase in water content. Interestingly, 60% of the mice in the vehicle arm developed seizures within 2 hours after cryoinjury versus none in the NRL-1049 arm. In spontaneously hypertensive rats, NRL-1049 attenuated the dramatic surge in Evans Blue extravasation compared with the vehicle arm after transient middle cerebral artery occlusion. Hemorrhagic transformation was also reduced. We show that NRL-1049, a selective ROCK2 inhibitor, is a promising drug candidate to preserve the BBB after brain injury.
PubMed: 38833563
DOI: 10.1177/0271678X241238845 -
Osteoarthritis and Cartilage May 2024To elucidate the local microcirculation of the infrapatellar fat pad (IFP) in patients with knee osteoarthritis (KOA) by determining the changes in IFP hardness and...
OBJECTIVE
To elucidate the local microcirculation of the infrapatellar fat pad (IFP) in patients with knee osteoarthritis (KOA) by determining the changes in IFP hardness and hemoglobin concentration during isometric quadriceps exercise (IQE).
DESIGN
In this observational cross-sectional study, patients diagnosed with bilateral KOA were included in the KOA group (30 knees), healthy older adults in the control group (20 knees), and younger adults in the young group (20 knees). Ultrasonography was performed at rest and during IQE to measure IFP hardness based on shear wave velocity. Near-infrared spectroscopy was performed to measure oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), and total hemoglobin (cHb) in the IFP before (Baseline), during (IQE task), and after IQE (Post). IFP hardness and O2Hb, HHb, and cHb concentration were analyzed using a linear mixed model for the groups and measurement points.
RESULTS
During IQE, IFP hardness changes were significantly less in the KOA group than in the other groups (KOA: 95 % confidence intervals (CIs) [-0.854, 0.028]; control: 95 % CI [-0.941, -0.341]; and young: 95 % CI [-2.305, -1.706]). In the KOA group, O2Hb concentration exhibited no significant changes at Post compared with Baseline; however, significant changes were observed in the other groups (KOA: 95 % CI [-1.176, 0.423]; control: 95 % CI [-1.452, -0.276]; and young: 95 % CI [-4.062, -2.102]).
CONCLUSIONS
During IQE, changes in hardness and hemoglobin concentration in the IFP were not significant in the KOA group, suggesting impaired local microcirculation of the IFP.
PubMed: 38824995
DOI: 10.1016/j.joca.2024.05.009 -
SLAS Technology May 2024Coronary microcirculation dysfunction (CMD) is one of the main causes of cardiovascular disease. Traditional treatment methods lack specificity, making it difficult to...
Coronary microcirculation dysfunction (CMD) is one of the main causes of cardiovascular disease. Traditional treatment methods lack specificity, making it difficult to fully consider the differences in patient conditions and achieve effective treatment and intervention. The complexity and diversity of CMD require more standardized diagnosis and treatment plans to clarify the best treatment strategy and long-term outcomes. The existing treatment measures mainly focus on symptom management, including medication treatment, lifestyle intervention, and psychological therapy. However, the efficacy of these methods is not consistent for all patients, and the long-term efficacy is not yet clear. GSEA is a bioinformatics method used to interpret gene expression data, particularly for identifying the enrichment of predefined gene sets in gene expression data. In order to achieve personalized treatment and improve the quality and effectiveness of interventions, this article combined GSEA (Gene Set Enrichment Analysis) technology to conduct in-depth research on potential drug targets and their interaction networks in coronary microcirculation dysfunctions. This article first utilized the Coremine medical database, GeneCards, and DrugBank public databases to collect gene data. Then, filtering methods were used to preprocess the data, and GSEA was used to analyze the preprocessed gene expression data to identify and calculate pathways and enrichment scores related to CMD. Finally, protein sequence features were extracted through the calculation of autocorrelation features. To verify the effectiveness of GSEA, this article conducted experimental analysis from four aspects: precision, receiver operating characteristic (ROC) curve, correlation, and potential drug targets, and compared them with Gene Regulatory Networks (GRN) and Random Forest (RF) methods. The results showed that compared to the GRN and RF methods, the average precision of GSEA improved by 0.11. The conclusion indicated that GSEA helped identify and explore potential drug targets and their interaction networks, providing new ideas for personalized quality of CMD.
PubMed: 38823582
DOI: 10.1016/j.slast.2024.100152 -
Journal of Advanced Research May 2024Sympathetic hyperinnervation plays an important role in modulating the vascular smooth muscle cell (VSMC) phenotype and vascular diseases, but its role in abdominal...
INTRODUCTION
Sympathetic hyperinnervation plays an important role in modulating the vascular smooth muscle cell (VSMC) phenotype and vascular diseases, but its role in abdominal aortic aneurysm (AAA) is still unknown.
OBJECTIVES
This study aimed to investigate the role of sympathetic hyperinnervation in promoting AAA development and the underlying mechanism involved.
METHODS
Western blotting and immunochemical staining were used to detect sympathetic hyperinnervation. We performed sympathetic denervation through coeliac ganglionectomy (CGX) and 6-OHDA administration to understand the role of sympathetic hyperinnervation in AAA and investigated the underlying mechanisms through transcriptome and functional studies. Sema4D knockout (Sema4D) mice were utilized to determine the involvement of Sema4D in inducing sympathetic hyperinnervation and AAA development.
RESULTS
We observed sympathetic hyperinnervation, the most important form of sympathetic neural remodeling, in both mouse AAA models and AAA patients. Elimination of sympathetic hyperinnervation by CGX or 6-OHDA significantly inhibited AAA development and progression. We further revealed that sympathetic hyperinnervation promoted VSMC phenotypic switching in AAA by releasing extracellular ATP (eATP) and activating eATP-P2rx4-p38 signaling. Moreover, single-cell RNA sequencing revealed that Sema4D secreted by osteoclast-like cells induces sympathetic nerve diffusion and hyperinnervation through binding to Plxnb1. We consistently observed that AAA progression was significantly ameliorated in Sema4D-deficient mice.
CONCLUSIONS
Sympathetic hyperinnervation driven by osteoclast-like cell-derived Sema4D promotes VSMC phenotypic switching and accelerates pathological aneurysm progression by activating the eATP/P2rx4/p38 pathway. Inhibition of sympathetic hyperinnervation emerges as a potential novel therapeutic strategy for preventing and treating AAA.
PubMed: 38821358
DOI: 10.1016/j.jare.2024.05.028 -
Photodiagnosis and Photodynamic Therapy May 2024Primary membranous nephropathy (PMN) patients may experience retinal microvascular changes. However, current diagnostic methods for PMN are not accurate in analyzing...
BACKGROUND
Primary membranous nephropathy (PMN) patients may experience retinal microvascular changes. However, current diagnostic methods for PMN are not accurate in analyzing these modifications. In the present study, optical coherence tomography angiography (OCTA) was used for quantitative measurement of microvascular changes in the eyes of PMN patients.
METHODS
A total of 26 patients with PMN and 26 healthy control (HC) were evaluated in this cross-sectional study. Optical coherence tomography (OCT) and OCTA were used to collect retinal thickness (RT) and microvascular parameters in the macula and optic disk in the superficial capillary plexus (SCP) of all subjects. Clinical data were collected from the PMN group. The OCT and OCTA data for PMN and HC group were compared, and the correlation between the OCTA and clinical data in the PMN group was determined.
RESULTS
Vascular density (VD) and perfusion density (PD) in the macular area of the PMN group were significantly lower than those of the HC group, especially in the temporal quadrant. No significant difference in the foveal avascular zone (FAZ), optic disc microvascular parameters, RT, and retinal nerve fiber layer (RNFL) thickness was observed between the two groups. Correlation was noted between VD and PD in the macular area and clinical indicators, such as serum creatinine, serum urea nitrogen, 24 h urine volume and urinary protein concentration.
CONCLUSION
Microvascular alterations in PMN patients occurred before ocular symptoms. The present quantitative study proposed a measurement method for detecting early retinal vascular injury in PMN patients.
PubMed: 38821236
DOI: 10.1016/j.pdpdt.2024.104230 -
Frontiers in Physiology 2024Glaucoma stands as a prominent global cause of irreversible blindness and the primary treatment approach involves reducing intraocular pressure (IOP). However, around...
BACKGROUND
Glaucoma stands as a prominent global cause of irreversible blindness and the primary treatment approach involves reducing intraocular pressure (IOP). However, around one-third of patients exhibit disease progression despite effective IOP reduction. Microvascular endothelial function, chronic inflammation, and oxidative stress are known to affect retinal neuronal networks and have been associated with disease severity and progression. Exercise training has the potential to counteract these mechanisms as add-on treatment to usual care.
AIMS
The HIT-GLAUCOMA study will investigate the effects of a 6-month high-intensity interval training (HIIT) on intermediate endpoints such as local retinal microvascular and systemic large artery function, inflammation, and oxidative stress as well as clinical endpoints such as visual field indices, optic nerve rim assessment, retinal nerve fiber layer thickness, IOP, number of eye drops, vision-related quality of life and ocular surface disease symptomatology.
METHODS
The study is a multi-center randomized controlled clinical trial in patients with both normal tension and high-tension primary open angle glaucoma. Across two study centers, 128 patients will be enrolled and randomized on a 1:1 basis into an exercise intervention group and a usual care control group. The primary microvascular endpoints are retinal arteriolar and venular flicker light-induced dilation at 6 months. The primary endpoint in the systemic circulation is brachial artery flow-mediated dilation at 6 months.
ANTICIPATED RESULTS
We hypothesize that exercise therapy will improve retinal microvascular function and thus ocular blood flow in patients with glaucoma. As clinical outcomes, we will investigate the effect of exercise on visual field indices, optic nerve rim assessment, retinal nerve fiber layer thickness, IOP, number of eye drops, vision-related quality of life and ocular surface disease symptomatology.
DISCUSSION
HIT-GLAUCOMA is a blueprint trial design to study the effect of exercise training on neurodegenerative and cardiovascular diseases. Importantly, patients are also expected to benefit from improvements in general health and cardiovascular co-morbidities. If proven effective, exercise may offer a new add-on treatment strategy to slow glaucoma progression.
CLINICAL TRIAL REGISTRATION NUMBER
The trial is registered at Clinicaltrials.gov under the identifier NCT06058598 and is currently in the recruitment stage.
PubMed: 38818519
DOI: 10.3389/fphys.2024.1349313 -
PloS One 2024Coronary microvascular dysfunction (CMD) is a critical pathogenesis of cardiovascular diseases. Lower endothelial nitric oxide synthase (eNOS) phosphorylation leads to...
Coronary microvascular dysfunction (CMD) is a critical pathogenesis of cardiovascular diseases. Lower endothelial nitric oxide synthase (eNOS) phosphorylation leads to reduced endothelium-derived relaxing factor nitric oxide (NO) generation, causing and accelerating CMD. Endoplasmic reticulum stress (ER stress) has been shown to reduce NO production in umbilical vein endothelial cells. Oxidized low-density lipoprotein (ox-LDL) damages endothelial cell function. However, the relationship between ox-LDL and coronary microcirculation has yet to be assessed. Short-chain fatty acid (SCFA), a fermentation product of the gut microbiome, could improve endothelial-dependent vasodilation in human adipose arterioles, but the effect of SCFA on coronary microcirculation is unclear. In this study, we found ox-LDL stimulated expression of ER chaperone GRP78. Further, we activated downstream PERK/eIF2a, IRE1/JNK, and ATF6 signaling pathways, decreasing eNOS phosphorylation and NO production in human cardiac microvascular endothelial. Furthermore, SCFA-propionate can inhibit ox-LDL-induced eNOS phosphorylation reduction and raise NO production; the mechanism is related to the inhibition of ER stress and downstream signaling pathways PERK/eIF2a, IRE1/JNK, and ATF6. In summary, we demonstrate that ox-LDL induced CMD by activating ER stress, propionate can effectively counteract the adverse effects of ox-LDL and protect coronary microcirculation function via inhibiting ER stress.
Topics: Humans; Endoplasmic Reticulum Stress; Lipoproteins, LDL; Nitric Oxide Synthase Type III; Endoplasmic Reticulum Chaperone BiP; Propionates; Nitric Oxide; Signal Transduction; Phosphorylation; Endothelial Cells; Coronary Vessels; Fatty Acids, Volatile; eIF-2 Kinase; Activating Transcription Factor 6; Microcirculation; Heat-Shock Proteins
PubMed: 38814895
DOI: 10.1371/journal.pone.0304551 -
Alternative Therapies in Health and... May 2024To investigate the mechanisms of ocular injuries in astronauts due to gravity deficit by examining changes in retinal microcirculation and visual electrophysiology in...
OBJECTIVE
To investigate the mechanisms of ocular injuries in astronauts due to gravity deficit by examining changes in retinal microcirculation and visual electrophysiology in macaques subjected to simulated weightlessness.
METHODS
The head-down recumbency of macaques was used to simulate the movement of blood to the side of the head that occurs without microgravity. Head-down recumbency was performed with the head tilted downwards at a recommended angle of 10°. The macaques in the control group were similarly tethered to the rope but could be held in a normal position. The whole experiment lasted for 6 weeks and retinal microcirculation and visual electrophysiology information was collected at weeks 0, 3 and 6.
RESULTS
The retinal microcirculation of macaques was affected by 3 weeks of weightlessness. This includes morphological changes, such as dilation and tortuosity of the retinal microvasculature in macaques at day 21. OCT and OCTA results showed an increase in retinal and choroidal thickness and a significant decrease in vessel length density within 6×6 mm of the macula. Sustained simulated weightlessness (42 days) significantly exacerbated retina-related damage. This was evidenced by a significant decrease in the perfusion density of microcirculatory vessels, such as the macular 3×3 mm mesial vessels and the macular 6*6 mm central and medial vessels. The FAZ density in the macula 3×3 mm area began to increase. Retinal oxygen saturation testing showed a slight increase in arterial oxygen saturation. Simultaneous changes in visual electrophysiology occurred, including a significant decrease in a- and b-wave amplitudes on the dark-vision electroretinogram and a significant decrease in the amplitude of the bright-vision negative wave response. The peak timing of the flash visual evoked potential component P1 was significantly delayed compared to its baseline and time-matched control.
CONCLUSIONS
Sustained simulated weightlessness (42 days) significantly exacerbated retina-related damage, with both reduced macular blood supply and increased FAZ density suggesting the development of retinal ischemic changes, which disrupt visual electrophysiology. Retinal damage in human astronauts under long-term outer space conditions may be prevented by intervening in ischemic changes in the retina during the early stages of weightlessness.
PubMed: 38814597
DOI: No ID Found