Microvascular System Research Articles

Associations of retinal microvascular density and fractal dimension with glaucoma: a prospective study from UK Biobank

ObjectiveTo explore the association between retinal microvascular parameters and glaucoma. DesignProspective study. SubjectsThe UK Biobank subjects with fundus images and without a history of glaucoma. MethodsWe employed the Retina-based Microvascular Health Assessment System (RMHAS) to utilize the noninvasive nature of fundus photography and quantify retinal microvascular parameters including retinal vascular skeleton density (VSD) and fractal dimension (FD). We also utilized propensity score matching (PSM) to pair individuals with glaucoma and healthy controls (HC). PSM was implemented via a logistic regression model with a caliper of 0.1 and a matching ratio of 1:4 sans replacements. We conducted univariable Cox regression analyses to study the association between retinal microvascular parameters and incident glaucoma, in both continuous and quartile forms. Main outcome measureVSD, FD, and glaucoma. ResultsIn a study of 41,632 participants without prior glaucoma, 482 cases of glaucoma were recorded during a median follow-up of 11.0 years. In the Cox proportional hazards regression model post-PSM, we found that incident glaucoma has significant negative associations with arteriolar VSD (HR = 0.24, 95% CI 0.11–0.52, P < 0.001), venular VSD (HR = 0.34, 95% CI 0.15–0.74, P = 0.007), arteriolar FD (HR = 0.24, 95% CI 0.10–0.60, P = 0.002) and venular FD (HR = 0.31, 95% CI 0.12–0.85, P = 0.022). Subgroup analysis using covariates revealed that individuals aged 60 and above, non-smokers, moderate alcohol consumers, and those with hypertension and myopia exhibited P values below 0.05 consistently pre- and post-matching, differing from other subgroups within this covariate. ConclusionOur study found that reduced retinal VSD and lower FD are linked to elevated glaucoma risk.

Engineered Biomimetic Nanoparticles-Mediated Targeting Delivery of Allicin Against Myocardial Ischemia-Reperfusion Injury by Inhibiting Ferroptosis.

Cardiac microvascular damage is substantially related with the onset of myocardial ischaemia-reperfusion (IR) injury. Reportedly, allicin (AL) effectively protects the cardiac microvascular system from IR injury. However, the unsatisfactory therapeutic efficacy of current drugs and insufficient drug delivery to the damaged heart are major concerns. Here, inspired by the natural interaction between neutrophils and inflamed cardiac microvascular endothelial cells (CMECs), a neutrophil membrane-camouflaged nanoparticle for non-invasive active-targeting therapy for IR injury by improving drug delivery to the injured heart is constructed. In this study, we engineered mesoporous silica nanoparticles (MSNs) coated with a neutrophil membrane to act as a drug delivery system, encapsulating AL. The potential of the nanoparticles (named AL@MSNs@NM) for specific targeting of infarcted myocardium was assessed using small animal vivo imaging system. The cardiac function of AL@MSNs@NM after treatment was evaluated by Animal Ultrasound Imaging system, HE staining, and Laser Speckle Imaging System. The therapeutic mechanism was analyzed by ELISA kits, immunofluorescence, and PCR. We discovered that AL@MSNs@NM significantly improves cardiac function index, reduced infarct size and fibrosis, increased vascular perfusion in ischemic areas, and also promoted the function of CMECs, including migration, tube formation, shear stress adaptation, and nitric oxide production. Further research revealed that AL@MSNs@NM have cardio-protective functions in IR rats by inhibiting CMEC ferroptosis and increasing platelet endothelial cell adhesion molecule-1 (PECAM-1) expression. Our results indicated that AL@MSNs@NM significantly reversed CMEC ferroptosis and increased PECAM-1 expression, enhanced cardiac function, and reduced myocardial infarction size. Therefore, this strategy demonstrates that engineered biomimetic nanotechnology effectively delivers AL for targeted therapy of myocardial infarction.

Alterations in Peripapillary and Macular Vasculature Measured by Optical Coherence Tomography Angiography and Their Clinical Correlation in Patients with Optic Neuritis Due to Multiple Sclerosis

Abstract Background Multiple Sclerosis (MS) is thought to be an autoimmune demyelinating disorder in which neuroaxonal degeneration is the principal driver of disability. Microvascular abnormalities in the central nervous system (CNS) may contribute to or be a biomarker of the disease process. Global reduction in cerebral perfusion has been repeatedly illustrated in imaging studies of MS, which could simply be a sequela of neurodegeneration or could be mediated by concomitant inflammatory vasculopathy. Endothelial cell dysfunction, excessive platelet activation, evidence of oxidative stress, altered blood- brain barrier permeability, vascular occlusions within demyelinating lesions, and hypoxia-like tissue injury have all been reported in people with MS (PwMS). Optical Coherence Tomography Angiography (OCTA) enables visualization of the ocular microvasculature through non-invasive, high-resolution enface and depth-resolved imaging. Using OCTA, non-invasive in vivo studies of neurological disorders through the human eye have emerged for MS, Alzheimer’s disease (AD), and various optic neuropathies. Objective To document changes in the peripapillary vascular network and retinal vascular plexuses in patients with optic neuritis due to MS and compare it to healthy individuals. Methods 26 eyes of 26 patients with Optic Neuritis (ON) caused by MS and 26 eyes of 26 sex and age- matched healthy controls. We used OCT AngioVue Enhanced Microvascular Imaging System aiming to quantify and compare microvasculature changes in the macula and peripapillary region between these two groups. this Cross-Sectional Study which has been conducted on patients from Ain Shams university hospitals, after the approval of the research ethics committee in the Faculty of Medicine, Ain Shams University between March to October. All cases underwent a Complete ophthalmological examination. the examination included Visual acuity assessment and Best corrected visual acuity. Slit Lamp Biomicroscopy examination with fundus examination, with OCT angiography (RTVue XR OCT Avanti System: Optovue, Fremont, USA) was done on the patients with MS during the attack of ON and to the healthy group. Results In our study, we found a statistically significant decrease in the superficial and deep vessel density in the macular area in the patients with ON compared to the healthy controls. Superficial vessel density in the macular area in the healthy ones was 49.90±3.4 (range: 42.4-54.6) while in those with MS was 44.09±4.9 (range 34.0-55.2). Deep vessel density in the macular area in patients without MS was 51.71±6.8 (range 35.3-61.4) while in patients with MS was 45.51±5.7 (range 37.0-57.8). There were statistically significant differences between groups (P = 0.001). Conclusion There is a decrease in superficial and deep vessel density and Radial peripapillary vessel density in patients with ON caused by MS in comparison to healthy controls.

Macrophages play a crucial role in vascular smooth muscle cell coverage.

The microvascular system consists of two cell types: endothelial and mural (pericytes and vascular smooth muscle cells; VSMCs) cells. Communication between endothelial and mural cells plays a pivotal role in the maintenance of vascular homeostasis; however, in vivo molecular and cellular mechanisms underlying mural cell development remain unclear. In this study, we found that macrophages played a crucial role in TGFβ-dependent pericyte-to-VSMC differentiation during retinal vasculature development. In mice with constitutively active Foxo1 overexpression, substantial accumulation of TGFβ1-producing macrophages and pericytes around the angiogenic front region was observed. Additionally, the TGFβ-SMAD pathway was activated in pericytes adjacent to macrophages, resulting in excess ectopic α-smooth muscle actin-positive VSMCs. Furthermore, we identified endothelial SEMA3C as an attractant for macrophages. In vivo neutralization of SEMA3C rescued macrophage accumulation and ectopic VSMC phenotypes in the mice, as well as drug-induced macrophage depletion. Therefore, macrophages play an important physiological role in VSMC development via the FOXO1-SEMA3C pathway.

Modulation of mechanosensitive genes during embryonic aortic arch development.

Early embryonic aortic arches (AA) are a dynamic vascular structures that are in the process of shaping into the great arteries of cardiovascular system. Previously, a time-lapsed mechanosensitive gene expression map was established for AA subject to altered mechanical loads in the avian embryo. To validate this map, we investigated effects on vascular microstructure and material properties following the perturbation of key genes using an in-house microvascular gene knockdown system. All siRNA vectors show a decrease in the expression intensity of desired genes with no significant differences between vectors. In TGFβ3 knockdowns, we found a reduction in expression intensities of TGFβ3 (≤76%) and its downstream targets such as ELN (≤99.6%), Fbn1 (≤60%), COL1 (≤52%) and COL3 (≤86%) and an increase of diameter in the left AA (23%). MMP2 knockdown also reduced expression levels in MMP2 (≤30%) and a 6-fold increase in its downstream target COL3 with a decrease in stiffness of the AA wall and an increase in the diameter of the AA (55%). These in vivo measurements were confirmed using immunohistochemistry, western blotting and a computational growth model of the vascular extracellular matrix (ECM). Localized spatial genetic modification of the aortic arch region governs the vascular phenotype and ECM composition of the embryo and can be integrated with mechanically-induced congenital heart disease models.

In vivo imaging of microvasculature in human finger skin using SV-OCT

Abstract Speckle variance optical coherence tomography (SV-OCT) enables non-invasive visualization of the three-dimensional vascular information within the microcirculatory tissue bed by utilizing flowing red blood cells as intrinsic contrast agents, without the need for dye injection. This study evaluated the feasibility of using the SV-OCT device for monitoring the microvascular system in human finger skin. An adaptive wavelet Fourier transform filtering algorithm was applied to remove stripe noise from the images of finger vasculature. The results demonstrate that SV-OCT systems can be used to extract the vascular system of finger skin. By employing an adaptive wavelet Fourier transform filtering (AWFTF)algorithm to process the vascular data, stripe noise can be effectively removed, thereby enhancing the imaging quality of the blood vessels.

Exosomes from Hypoxia Preconditioned Muscle-Derived Stem Cells Enhance Cell-Free Corpus Cavernosa Angiogenesis and Reproductive Function Recovery.

Tissue engineering for penile corpora cavernosa defects requires microvascular system reconstruction.GelMA hydrogels show promise for tissue regeneration. However, using stem cells faces challenges such as immune rejection, limited proliferation and differentiation, and biosafety concerns. Therefore, acellular tissue regeneration may avoid these issues. Exosomes are used from muscle-derived stem cells (MDSCs) to modify 3D-printed hydrogel scaffolds for acellular tissue regeneration. Hypoxia-preconditioned MDSC-derived exosomes are obtained to enhance the therapeutic effect. In contrast to normoxic exosomes (N-Exos), hypoxic exosomes (H-Exos) are found to markedly enhance the proliferation, migration, and capillary-like tube formation of human umbilical vein endothelial cells (HUVECs). High-throughput sequencing analysis of miRNAs isolated from both N-Exos and H-Exos revealed a significant upregulation of miR-21-5p in H-Exos following hypoxic preconditioning. Further validation demonstrated that the miR-21-5p/PDCD4 pathway promoted the proliferation of HUVECs. Epigallocatechin gallate (EGCG) is introduced to improve the mechanical properties and biocompatibility of GelMA hydrogels. EGCG-GelMA scaffolds loaded with different types of Exos are transplanted to repair rabbit penile corpora cavernosa defects, observed the blood flow and repair status of the defect site through color Doppler ultrasound and magnetic resonance imaging, and ultimately restored the rabbit penile erection function and successfully bred offspring. Thus, acellular hydrogel scaffolds offer an effective treatment for penile corpora cavernosa defects.

Efficient Microbubble Trajectory Tracking in Ultrasound Localization Microscopy Using a Gated Recurrent Unit-Based Multitasking Temporal Neural Network.

Ultrasound Localization Microscopy (ULM), an emerging medical imaging technique, effectively resolves the classical trade-off between resolution and penetration inherent in traditional ultrasound imaging, opening up new avenues for noninvasive observation of the microvascular system. However, traditional microbubble tracking methods encounter various practical challenges. These methods typically entail multiple processing stages, including intricate steps like pairwise correlation and trajectory optimization, rendering real-time applications unfeasible. Furthermore, existing deep learning-based tracking techniques neglect the temporal aspects of microbubble motion, leading to ineffective modeling of their dynamic behavior. To address these limitations, this study introduces a novel approach called the Gated Recurrent Unit (GRU)-based Multitasking Temporal Neural Network (GRU-MT). GRU-MT is designed to simultaneously handle microbubble trajectory tracking and trajectory optimization tasks. Additionally, we enhance the nonlinear motion model initially proposed by Piepenbrock et al. to better encapsulate the nonlinear motion characteristics of microbubbles, thereby improving trajectory tracking accuracy. In this study, we perform a series of experiments involving network layer substitutions to systematically evaluate the performance of various temporal neural networks, including Recurrent Neural Networks (RNN), Long Short-Term Memory (LSTM), GRU, Transformer, and its bidirectional counterparts, on the microbubble trajectory tracking task. Concurrently, the proposed method undergoes qualitative and quantitative comparisons with traditional microbubble tracking techniques. The experimental results demonstrate that GRU-MT exhibits superior nonlinear modeling capabilities and robustness, both in simulation and in vivo dataset. Additionally, it achieves reduced trajectory tracking errors in shorter time intervals, underscoring its potential for efficient microbubble trajectory tracking. Model code is open-sourced at https://github.com/zyt-Lib/GRU-MT.

Efficiency and safety of microvascular anastomotic coupler for wrist revascularization in traumatic injuries

IntroductionEffective vascular anastomosis is crucial for successful hand surgery, particularly in traumatic injuries where rapid restoration of blood flow is essential. The Synovis microvascular anastomotic coupler system presents a novel approach by potentially offering faster and more reliable outcomes than traditional suturing methods. This study was conducted to assess the effectiveness and safety of the Synovis coupler for microvascular anastomoses in the wrist, evaluating anastomosis time, patency rates, and complication rates. MethodsThis retrospective study examined 25 microvascular anastomoses (22 arteries and 3 veins) in 24 patients at a major trauma center. The primary outcomes measured were anastomosis time and vascular patency, which were assessed immediately post-operation and at subsequent follow-ups. ResultsThe average time required for anastomosis using the coupler was 7.3 min. Immediate post-operative vascular patency was 100%, with a long-term patency rate of 88%. Complications included arterial narrowing at the coupler site in 3 arteries, and complete occlusion in 3 arteries, accounting for a 12% long-term complication rate. ConclusionAlthough the Synovis coupler demonstrated a significant reduction in anastomosis time and high patency rates, our data suggest that its effectiveness is more pronounced in venous anastomoses. The higher complication rates in arterial anastomoses warrant cautious use in these cases. Further research, including prospective randomized controlled trials, is needed to validate these findings and optimize patient selection criteria for using couplers in microvascular surgery.

The Microvascular Anastomotic Coupler for Venous Anastomosis in Head and Neck Reconstruction: An Institutional Experience.

Background This study aimed to identify outcome predictors with the GEM microvascular coupler system (GEM Coupler) in a series of patients undergoing free flap reconstruction for head and neck defects. Methodology In this retrospective chart review of 218 consecutive microvascular procedures performed on 204 patients at an academic tertiary care center, demographics, comorbidities, surgical data, and outcomes were retrieved. The endpoints for the analysis were microvascular revision surgery and flap survival. Results The study included 142 (70.2%) males and 62 (29.8%) females, with a mean age of 56 years, primarily treated for malignancy (76%). The anterolateral thigh and fibula were the most commonly used flaps (40.4% and 27.1%, respectively). In 21 (9.6%) cases, a double venous anastomosis was performed. There were nine flap failures requiring microvascular revision surgery; the flap was salvaged in four of these cases yielding an overall success rate of 97.7%. Factors associated with total flap loss included a history of a thrombotic or embolic event (p = 0.017), deep circumflex iliac artery flap (p < 0.001), and absence of monitoring skin paddle (p < 0.001). Conclusions Prothrombotic conditions, buried flaps, and flap type are outcome predictors in patients undergoing microvascular reconstruction with GEM Coupler.

Changes in peripapillary and macular vasculature measured by optical coherence tomography angiography and their clinical correlation in patients with optic neuritis due to multiple sclerosis

Aim To document changes in the peripapillary vascular network and retinal vascular plexuses in patients with optic neuritis (ON) due to multiple sclerosis (MS) and compare it with healthy individuals. Settings and design A prospective comparative case–control study performed at the Ophthalmology Department of a tertiary-level university hospital, between November 2020 and November 2022. Patients and methods In all, 26 eyes of 26 patients with ON caused by MS and 26 eyes of 26 sex-matched and age-matched healthy controls. We used optical coherence tomography AngioVue Enhanced Microvascular Imaging System aiming to quantify and compare microvasculature changes in the macula and peripapillary region between the two groups. Results We found a statistically significant decrease in the superficial and deep vessel density in the macular area in patients with ON compared with the healthy controls. Superficial vessel density in the macular area in the healthy ones was 49.90±3.4, while in those with MS was 44.09±4.9 (P&lt;0.001). Deep vessel density in the macular area in patients without MS was 51.71±6.8 while in patients with MS was 45.51±5.7 (P&lt;0.001). Conclusion There is a decrease in superficial and deep vessel density and radial peripapillary vessel density in patients with ON caused by MS in comparison to healthy controls.

Relation of the oxygen saturation and blood flow in different structural parts of the microvascular system of the human skin

Relation of the oxygen saturation and blood flow in different structural parts of the microvascular system of the human skin

Hepatic-derived BMP9 is involved in hepatic fibrosis-induced kidney injury through inhibition of renal VEGFA

Clinical observations suggest that acute kidney injury (AKI) occurs in approximately 20–50% of hospitalized cirrhotic patients, suggesting a link between the liver and kidney. Bone morphogenetic protein 9 (BMP9) is a protein produced primarily by the liver and can act on other tissues at circulating systemic levels. Previous studies have demonstrated that controlling abnormally elevated BMP9 in acute liver injury attenuates liver injury; however, reports on whether BMP9 plays a role in liver injury-induced AKI are lacking. By testing we found that liver injury in mice after bile duct ligation (BDL) was accompanied by a significant upregulation of the kidney injury marker kidney injury molecule (KIM-1). Interestingly, all these impairments were alleviated in the kidneys of hepatic BMP9 knockout (BMP9-KO) mice. Peritubular capillary injury is a key process leading to the progression of AKI, and previous studies have demonstrated that vascular endothelial growth factor A (VEGFA) plays a key role in maintaining the renal microvascular system. In animal experiments, we found that high levels of circulating BMP9 had an inhibitory effect on VEGFA expression, while renal tubular epithelial cell injury was effectively attenuated by VEGFA supplementation in the hypoxia-enriched-oxygen (H/R) constructs of the AKI cell model in both humans and mice. Overall, we found that elevated BMP9 in hepatic fibrosis can affect renal homeostasis by regulating VEGFA expression. Therefore, we believe that targeting BMP9 therapy may be a potential means to address the problem of clinical liver fibrosis combined with AKI.

Fullerenol-mediated vascular regeneration and radioprotection: A strategy for tissue recovery post-radiation

Radiation therapy is crucial in combating malignant tumors, yet its damage to the microvascular system can significantly impair patient recovery and prognosis. Although current radiation protection measures mitigate free radical damage to target organs, they fall short in safeguarding the surrounding microvasculature. This study pioneers the use of the matrigel plug angiogenesis model to investigate the application of the water-soluble fullerene derivative Fullerenol in microvascular radioprotection, aiming to effectively protect and repair the microvascular system during radiation therapy, thereby reducing its adverse effects on healthy tissues. Our findings demonstrate that Fullerenol not only efficiently scavenges free radicals, reducing radiation-induced damage, but also promotes endothelial cell proliferation, facilitating the repair of damaged microvasculature and surrounding tissues. Additionally, Fullerenol was found to inhibit Caspase-3 and activate the PI3K/AKT (Phosphoinositide 3-kinase/Protein kinase B) proliferation metabolic pathway and its downstream proteins, such as eNOS and VEGF (Endothelial nitric oxide synthase/Vascular endothelial growth factor), decreasing endothelial cell apoptosis and maintaining vascular proliferation and angiogenesis potential. This research provides a new option for microvascular radioprotection and offers fresh insights into the repair of tissues damaged by radiation therapy.

Retinal Microvasculature in Systemic Sclerosis Patients and the Correlation between Nailfold Capillaroscopic Findings and Optical Coherence Angiography Results.

Background: The comparison of retinal perfusion in the eyes of patients with systemic sclerosis (SSc) and in healthy controls using optical coherence tomography angiography (OCTA). The correlation between nailfold capillaroscopy results and OCTA findings among SSc. Methods: The study enrolled 31 patients with systemic sclerosis and 41 healthy controls. OCTA was performed in both groups to assess the retinal vasculature in the superficial (SCP) and deep (DCP) capillary plexuses and the foveal avascular zone (FAZ) area. Nailfold capillaroscopy (NC) was performed in SSc patients and compared to the FAZ area and the superficial and the deep vessel density. Results: In the SSc group, the parafoveal vessel density in DCP was significantly higher in relation to the mean value (p < 0.0001) and in each quadrant of the macula (p < 0.0001) compared to healthy subjects (p < 0.0001). The patients with early scleroderma patterns in capillaroscopy had a larger superficial and deep FAZ (p = 0.0104, p = 0.0076, respectively) than those with active and late patterns. There was a statistically significant difference in the FAZ when comparing early to active (p < 0.0001) and early to late scleroderma patterns (p < 0.0001). A statistically significant difference was found in the type of interstitial lung disease and the deep FAZ area (p = 0.0484). SSc patients with nonspecific interstitial pneumonia (NSIP) had a larger FAZ than those with usual interstitial pneumonia (UIP) (p = 0.0484). Moreover, NSIP cases had a higher parafoveal mean superficial vessel density than those with UIP (p = 0.0471). Conclusions: Our investigation showed that the peripheral microvascular system correlates with ocular microcirculatory impairment. The results indicate the important role of OCTA in the diagnosis, monitoring, and prognosis of microvascular changes in SSc.

The Unpredictable Ulnar Nerve-Ulnar Nerve Entrapment from Anatomical, Pathophysiological, and Biopsychosocial Aspects.

Peripheral nerves consist of delicate structures, including a rich microvascular system, that protect and nourish axons and associated Schwann cells. Nerves are sensitive to internal and external trauma, such as compression and stretching. Ulnar nerve entrapment, the second most prevalent nerve entrapment disorder after carpal tunnel syndrome, appears frequently at the elbow. Although often idiopathic, known risk factors, including obesity, smoking, diabetes, and vibration exposure, occur. It exists in all adult ages (mean age 40-50 years), but seldom affects individuals in their adolescence or younger. The patient population is heterogeneous with great co-morbidity, including other nerve entrapment disorders. Typical early symptoms are paresthesia and numbness in the ulnar fingers, followed by decreased sensory function and muscle weakness. Pre- and postoperative neuropathic pain is relatively common, independent of other symptom severity, with a risk for serious consequences. A multimodal treatment strategy is necessary. Mild to moderate symptoms are usually treated conservatively, while surgery is an option when conservative treatment fails or in severe cases. The decision to perform surgery might be difficult, and the outcome is unpredictable with the risk of complications. There is no consensus on the choice of surgical method, but simple decompression is relatively effective with a lower complication rate than transposition.

Subcutaneous injection of hyaluronic acid leading to emboliom and recanalization process monitored in real time by three-dimensional photoacoustic imaging

This study describes a method for real-time examination of the microvascular system based on the three-dimensional photoacoustic imaging system to prevent arterial complications, especially vascular embolism, during hyaluronic acid (HA) injections. Chicken embryos were used to simulate the superficial blood vessels of human skin, and then the target area was imaged by the photoacoustic imaging system for three-dimensional vascular imaging, and then the syringe and blood vessels were monitored, and the syringe angle and penetration depth were adjusted in time using an injection device to avoid puncturing the arterial vasculature and clogging the blood vessels. HA was then injected into smaller vessels on the dorsum of the tongue in mice and into thicker vessels on the dorsal portion of the tongue in rats to mimic embolization, and the post-operative recovery was reflected by the changes in the pixel dots of the extracted part of the blocked blood vessels, and it was observed that the blood flow in the area of the fine vessels was restored in about 3 days, whereas blood flow in the area of the large vessels was restored in only about 1 h. The method presented in this paper allows precise guidance of injectable filler HA, which has good application prospects in improving the safety of injection micro-plastic surgery and reducing the experience requirements for medical personnel.

Effects of repeated low-level red-light therapy on macular retinal thickness and microvascular system in children with myopia

ObjectiveThe objective of the study was to use optical coherence tomography angiography (OCTA) to analyze the effects of repeated low-level red-light (LLLT) therapy on macular retinal thickness and the microvascular system in children with myopia to evaluate the safety of this therapy. MethodsThis prospective study included 40 school-age children with myopia (80 eyes), aged 7–14 years, who received therapy using a LLLT instrument. At baseline and therapy for 1 month, 3 months, 6 months, all children underwent comprehensive ophthalmological examinations, including slit-lamp examination, uncorrected visual acuity, best-corrected visual acuity, spherical equivalent degree, axial length, and OCTA. The vessel densities of the superficial retinal capillary plexus, macular inner retinal thickness, and full-layer retinal thickness were measured. ResultsThe macular inner retinal thickness increased at 1 month and remained unchanged thereafter, It differed significantly in nine areas at 1, 3, and 6 months compared to the thicknesses before therapy (P < 0.05); however, we observed no significant differences between the different time points (P > 0.05). The macular full-layer retinal thickness increased at 1 month and remained unchanged thereafter; the changes showed significant differences at 1 month and 3 months compared to before therapy, for the inner nasal region (P < 0.05). The other eight areas showed significant differences at 1, 3, and 6 months compared with before therapy (P < 0.05); however, no significant difference was observed between the different time points after therapy (P > 0.05). The vessel density of the superficial retinal capillary plexus did not differ significantly among the four groups (P > 0.05). ConclusionsLLLT therapy was safe. The school-aged children exhibited macular thickening after LLLT therapy, which had no significant effect on macular microcirculation.

Evaluation of renal circulation in heart failure using superb microvascular imaging, a microvascular flow imaging system.

Renal circulation evaluation is essential in understanding the cardiorenal relationship in heart failure (HF), and there is a growing interest in imaging techniques that visualize renal circulation. This study aimed to assess the effectiveness of superb microvascular imaging (SMI) in evaluating renal circulation in HF patients. The study included 71 HF patients undergoing cardiac catheterization. Prior to catheterization, renal ultrasound examinations were performed. A control group of 18 subjects without HF was also included. SMI was used to measure the vascular index (VI), which was calculated as the percentage of blood flow signal area in the region of interest. The intrarenal perfusion index (IRPI) was determined as a fluctuation index of VI, reflecting variations in the number of blood cells moving through renal tissue during the cardiac cycle. Using the upper 95% confidence interval of IRPI (0.6) from the control group, HF patients were classified into two groups. Patients with IRPI > 0.6 showed a more congestive profile. Right atrial pressure and biphasic or monophasic Doppler intrarenal flow pattern were independent determinants of IRPI > 0.6. In addition, IRPI remained a significant predictor of estimated glomerular filtration rate (eGFR). The parameter IRPI as variations in SMI signal during the cardiac cycle may be a useful evaluation method for renal perfusion impairment in HF.

Retinal Vascular Measurements and Mortality Risk: Evidence From the UK Biobank Study.

This study aimed to investigate the association between quantitative retinal vascular measurements and the risk of all-cause and premature mortality. In this population-based cohort study using the UK Biobank data, we employed the Retina-based Microvascular Health Assessment System to assess fundus images for image quality and extracted 392 retinal vascular measurements per fundus image. These measurements encompass six categories of vascular features: caliber, density, length, tortuosity, branching angle, and complexity. Univariate Cox regression models were used to identify potential indicators of mortality risk using data on all-cause and premature mortality from death registries. Multivariate Cox regression models were then used to test these associations while controlling for confounding factors. The final analysis included 66,415 participants. After adjusting for demographic, health, and lifestyle factors and genetic risk score, 18 and 10 retinal vascular measurements were significantly associated with all-cause mortality and premature mortality, respectively. In the fully adjusted model, the following measurements of different vascular features were significantly associated with all-cause mortality and premature mortality: arterial bifurcation density (branching angle), number of arterial segments (complexity), interquartile range and median absolute deviation of arterial curve angle (tortuosity), mean and median values of mean pixel widths of all arterial segments in each image (caliber), skeleton density of arteries in macular area (density), and minimum venular arc length (length). The study revealed 18 retinal vascular measurements significantly associated with all-cause mortality and 10 associated with premature mortality. Those identified parameters should be further studied for biological mechanisms connecting them to increased mortality risk. This study identifies retinal biomarkers for increased mortality risk and provides novel targets for investigating the underlying biological mechanisms.