Microvascular Alterations Research Articles

Microvascular blood flow disturbances predict poor outcome of revascularization in CLTI patients

Abstract Background We have recently established hypoxic microvascular remodelling as a critical pathomechanistic factor that limits oxygen diffusion to muscle in chronic limb threatening ischaemia (CLTI). Using animal models of experimental hind limb ischaemia we have also displayed the biological relevance of post-ischaemic microvascular remodelling in skeletal muscle. Our results indicate that differential microvascular changes associate to muscle damage and repair. The natural microvascular dynamics that inherently promote muscle recovery are defected in CLTI patients. Particularly, a progressive arterialization of capillaries in CLTI muscle differentiates the dynamics of the microvasculature from initially assisting muscle regeneration to aggravating ischaemic damage. Methods To establish the clinical relevance of the post-ischaemic microvascular changes in CLTI, we now have studied the effect of microvascular remodelling on the outcome of CLTI patients undergoing surgical or endovascular revascularization. Contrast enhanced ultrasound was used preoperatively to determine the microvascular status of CLTI patients (n=36) scheduled for immediate revascularization. Outcome events such as: hospitalization; reoperation; leg amputation; or death, were postoperatively followed from medical records up to 6 months after revascularization. Patients were grouped according to muscle capillary transit time (Tct) being either similar (n=18) or shorter (n=18) to that in the contralateral legs of the patients, and treatment outcomes were compared between groups. Results The results display consistent increases in postoperative event rates in all measured outcomes in the ShortTct group as compared to controls (at 1 month 8 vs. 2 events (rate ratio 4.00 (95%CI: 0.85-18.84, p=0.080)); at 3 months 13 vs. 4 events (rate ratio 3.25 (95%CI: 1.06-9.97, p=0.039)); at 6 months 17 vs. 9 events (rate ratio 1.89 (95%CI: 0.84-4.24, p=0.123))). For example, 5 vs. 0; 7 vs. 1; and 7 vs. 4 reoperations were detected in the ShortTct group as compared to controls at 1, 3 and 6 months, respectively. By 6 months after initial revascularization also 2 deaths were recorded in the ShortTct group as compared to no deaths in the controls. Conclusions Despite still small samples size in this study, these results suggest that microvascular blood flow disturbances, such as short preoperative muscle capillary transit time, can predict poor outcome of CLTI patients after revascularization. Importantly, the results also identify patients with microvascular blood flow disturbances a subgroup of CLTI patients that should likely receive more specialized care to improve outcomes. The results also call for immediate actions from the scientific community to improve clinical detection of microvascular alterations and to develop strategies to normalize microvascular function in CLTI patients.

The Potential Impact of Gestational Diabetes Mellitus on Long-Term Kidney Disease: A Narrative Review

Gestational diabetes mellitus (GDM) is a pervasive metabolic disorder associated with a spectrum of long-term adverse outcomes. Recent evidence indicates that women with GDM have a heightened subsequent risk of kidney disease. Persistent factors, both pre-gestational and postpartum, can contribute to these adverse outcomes years after a GDM pregnancy. Metabolic features such as insulin resistance, subclinical inflammation, and endothelial dysfunction can lead to enduring microvascular alterations, ultimately resulting in long-term renal complications. The insulin resistance and beta cell dysfunction that develop during GDM are chronic and progressive, increasing the risk of Type 2 diabetes mellitus, hypertension, and dyslipidaemia, all risk factors for chronic kidney disease (CKD). While few studies have specifically investigated the independent association between GDM and subsequent renal dysfunction, a recent study examining the adverse pregnancy outcomes and long-term risk of CKD identified GDM as one of the independent risk factors. The findings of this review strongly recommend that women who experience adverse pregnancy outcomes like GDM during their reproductive years should be well-informed about their long-term risk of kidney disease. This knowledge is essential for early preventive actions and follow-up care. In future, cardiometabolic surveillance and risk modification strategies in clinical practice are necessary to prevent maternal renal complications among women with a history of GDM.

Outcomes of acute kidney injury continuum in children.

Acute kidney injury (AKI) is associated with high morbidity and mortality. The continuum of kidney damage after an AKI episode is poorly explored in the paediatric population. We performed a retrospective cohort study on 2346 children with AKI from a tertiary care hospital in Romania over a 9-year period. The main objective was to evaluate the impact of AKI duration on mortality and the risk of new-onset chronic kidney disease (CKD). Out of 2346 AKI patients, transient AKI was present in 655 patients (27.9%), persistent AKI in 1009 children (43%) and acute kidney disease in 682 patients (29.1%). In contrast to transient AKI, children who developed acute kidney disease were younger, with a higher degree of anaemia, lower number of platelets, higher procalcitonin, higher LDH, higher GGT, higher urea and higher serum creatinine levels. The pre-renal cause of AKI was the leading cause regardless of AKI duration. As kidney injury progressed over time, there was an increasing incidence of the intrinsic causes of AKI (11.1% in transient AKI, 13.2% in persistent AKI and 22.6% in acute kidney disease). Acute kidney disease patients had the highest mortality rate (16.42%), followed by transient AKI (14.66%) and persistent AKI (9.81%). Overall mortality increased in the presence of renal microvascular alterations, acute tubular necrosis, lower haemoglobin, serum proteins and platelets, and higher procalcitonin levels. The continuum of AKI expressed as acute kidney disease resulted in an increased risk of new-onset CKD. CKD was influenced by the intrinsic cause of AKI and not by AKI severity.

Microvascular alterations of the ocular surface and retina in connective tissue disease-related interstitial lung disease.

To examine the disparities in macular retinal vascular density between individuals with connective tissue disease-related interstitial lung disease (CTD-ILD) and healthy controls (HCs) by optical coherence tomography angiography (OCTA) and to investigate the changes in microvascular density in abnormal eyes. For a retrospective case-control study, a total of 16 patients (32 eyes) diagnosed with CTD-ILD were selected as the ILD group. The 16 healthy volunteers with 32 eyes, matched in terms of age and sex with the patients, were recruited as control group. The macular retina's superficial retinal layer (SRL) and deep retinal layer (DRL) were examined and scanned using OCTA in each individual eye. The densities of retinal microvascular (MIR), macrovascular (MAR), and total microvascular (TMI) were calculated and compared. Changes in retinal vascular density in the macular region were analyzed using three different segmentation methods: central annuli segmentation method (C1-C6), hemispheric segmentation method [uperior right (SR), superior left (SL), inferior left (IL), and inferior right (IR)], and Early Treatment Diabetic Retinopathy Study (ETDRS) methods [superior (S), inferior (I), left (L), and right (R)]. The data were analyzed using Version 9.0 of GraphPad prism and Pearson analysis. The OCTA data demonstrated a statistically significant difference (P<0.05) in macular retinal microvessel density between the two groups. Specifically, in the SRL and DRL analyses, the ILD group exhibited significantly lower surface density of MIR and TMI compared to the HCs group (P<0.05). Furthermore, using the hemispheric segmentation method, the ILD group showed notable reductions in SL, SR, and IL in the superficial retina (P<0.05), as well as marked decreases in SL and IR in the deep retina (P<0.05). Similarly, when employing the ETDRS method, the ILD group displayed substantial drops in superficial retinal S and I (P<0.05), along with notable reductions in deep retinal L, I, and R (P<0.05). In the central annuli segmentation method, the ILD group exhibited a significant decrease in the superficial retinal C2-4 region (P<0.05), whereas the deep retina showed a notable reduction in the C3-5 region (P<0.05). Additionally, there was an observed higher positive likelihood ratio in the superficial SR region and deep MIR. Furthermore, there was a negative correlation between conjunctival vascular density and both deep and superficial retinal TMI (P<0.001). Patients with CTD-ILD exhibits a significantly higher conjunctival vascular density compared to the HCs group. Conversely, their fundus retinal microvascular density is significantly lower. Furthermore, CTD-ILD patients display notably lower superficial and deep retinal vascular density in comparison to the HCs group. The inverse correlation between conjunctival vascular density and both superficial and deep retinal TMI suggests that detecting subtle changes in ocular microcirculation could potentially serve as an early diagnostic indicator for connective tissue diseases, thereby enhancing disease management.

Microangiopathy in temporal lobe epilepsy with diffusion MRI alterations and cognitive decline

White matter microvascular alterations in temporal lobe epilepsy (TLE) may be relevant to acquired neurodegenerative processes and cognitive impairments associated with this condition. We quantified microvascular changes, myelin, axonal, glial and extracellular-matrix labelling in the gyral core and deep temporal lobe white matter regions in surgical resections from 44 TLE patients with or without hippocampal sclerosis. We compared this pathology data with in vivo pre-operative MRI diffusion measurements in co-registered regions and neuropsychological measures of cognitive impairment and decline. In resections, increased arteriolosclerosis was observed in TLE compared to non-epilepsy controls (greater sclerotic index, p < 0.001), independent of age. Microvascular changes included increased vascular densities in some regions but uniformly reduced mean vascular size (quantified with collagen-4, p < 0.05–0.0001), and increased pericyte coverage of small vessels and capillaries particularly in deep white matter (quantified with platelet-derived growth factor receptorβ and smooth muscle actin, p < 0.01) which was more marked the longer the duration of epilepsy (p < 0.05). We noted increased glial numbers (Olig2, Iba1) but reduced myelin (MAG, PLP) in TLE compared to controls, particularly prominent in deep white matter. Gene expression analysis showed a greater reduction of myelination genes in HS than non-HS cases and with age and correlation with diffusion MRI alterations. Glial densities and vascular size were increased with increased MRI diffusivity and vascular density with white matter abnormality quantified using fixel-based analysis. Increased perivascular space was associated with reduced fractional anisotropy as well as age-accelerated cognitive decline prior to surgery (p < 0.05). In summary, likely acquired microangiopathic changes in TLE, including vascular sclerosis, increased pericyte coverage and reduced small vessel size, may indicate a functional alteration in contractility of small vessels and haemodynamics that could impact on tissue perfusion. These morphological features correlate with white matter diffusion MRI alterations and might explain cognitive decline in TLE.

The urotensin II receptor triggers an early meningeal response and a delayed macrophage-dependent vasospasm after subarachnoid hemorrhage in male mice

Subarachnoid hemorrhage (SAH) can be associated with neurological deficits and has profound consequences for mortality and morbidity. Cerebral vasospasm (CVS) and delayed cerebral ischemia affect neurological outcomes in SAH patients, but their mechanisms are not fully understood, and effective treatments are limited. Here, we report that urotensin II receptor UT plays a pivotal role in both early events and delayed mechanisms following SAH in male mice. Few days post-SAH, UT expression is triggered by blood or hemoglobin in the leptomeningeal compartment. UT contributes to perimeningeal glia limitans astrocyte reactivity, microvascular alterations and neuroinflammation independent of CNS-associated macrophages (CAMs). Later, CAM-dependent vascular inflammation and subsequent CVS develop, leading to cognitive dysfunction. In an SAH model using humanized UTh+/h+ male mice, we show that post-SAH CVS and behavioral deficits, mediated by UT through Gq/PLC/Ca2+ signaling, are prevented by UT antagonists. These results highlight the potential of targeting UT pathways to reduce early meningeal response and delayed cerebral ischemia in SAH patients.

Unveiling the intricacies of chronic kidney disease: From ocular manifestations to therapeutic frontiers.

Shared anatomical, histological and physiological pathways between the kidney and the eye are well documented, demonstrating that ocular manifestations serve as valuable prognostic indicators in chronic kidney disease (CKD), providing insights into disease severity and progression. Through non-invasive imaging modalities such as retinal fundus photography, early retinal microvascular alterations indicative of CKD progression can be detected, enabling timely intervention and risk stratification. However, the conclusions drawn from the review primarily demonstrate a strong or independent association between glaucoma or retinopathy and CKD. Multiple shared pathophysiological events have been implicated in the pathogenesis in the alterations at eye and kidney including renin-angiotensin-aldosterone system. Patients with CKD are more likely to experience glaucoma, age-related macular degeneration, cataracts, uremic optic neuropathy and retinopathy. To establish the role of ocular manifestations in predicting CKD progression, it is crucial to address the limitations of correlation and explore the underlying causality with further research on common disease pathogenesis. Additionally, specific methods for risk stratification based on retinal changes, the effectiveness of timely interventions, and the development of predictive tools combining ocular and renal data are of utmost importance research topics to enlighten the bidirectional causality.

Retinal Microvasculature Changes Linked to Executive Function Impairment after COVID-19

Background/Objectives: Studies using optical coherence tomography angiography (OCTA) have revealed that individuals recovering from COVID-19 have a reduced retinal vascular density (VD) and larger foveal avascular zones (FAZs) than healthy individuals, with more severe cases showing greater reductions. We aimed to examine aspects of the retinal microvascularization in patients with post-COVID-19 condition (PCC) classified by COVID-19 severity and how these aspects relate to cognitive performance. Methods: This observational cross-sectional study included 104 PCC participants from the NAUTILUS Project, divided into severe (n = 59) and mild (n = 45) COVID-19 groups. Participants underwent cognitive assessments and OCTA to measure VD and perfusion density (PD) in the superficial capillary plexus (SVP) and FAZ. Analysis of covariance and partial Pearson and Spearman correlations were used to study intergroup differences and the relationships between cognitive and OCTA variables. Results: Severe PCC participants had significantly lower central (p = 0.03) and total (p = 0.03) VD, lower central (p = 0.02) PD measurements, and larger FAZ areas (p = 0.02) and perimeters (p = 0.02) than mild cases. Severe cases showed more cognitive impairment, particularly in speed processing (p = 0.003) and executive functions (p = 0.03). Lower central VD, lower central PD, and larger FAZ areas and perimeters were associated with worse executive function performance in the entire PCC sample and in the mild COVID-19 group. Conclusions: Retinal microvascular alterations, characterized by reduced VD and PD in the SVP and larger FAZ areas, were associated with cognitive impairments in PCC individuals. These findings suggest that severe COVID-19 leads to long-lasting microvascular damage, impacting retinal and cognitive health.

Retinal Microvascular Changes in Association with Endothelial Glycocalyx Damage and Arterial Stiffness in Patients with Diabetes Mellitus Type 2: A Cross-Sectional Study in a Greek Population.

To evaluate the potential association between endothelial glycocalyx damage, as well as arterial stiffness, and the retinal changes on optical coherence tomography (OCT) and OCT-angiography (OCT-A) in patients with type 2 diabetes mellitus (DM). Participants in this cross-sectional study were 65 patients with DM type 2 and 42 age- and gender-matched controls without DM. The demographic and clinical characteristics of the participants were recorded. All patients underwent a thorough ophthalmological examination and multimodal imaging, including fundus photography, OCT, and OCT-A. In addition, evaluation of the endothelial glycocalyx thickness by measuring the perfused boundary region (PBR5-25) of the sublingual microvessel, as well as of the arterial stiffness, by measuring the carotid-femoral pulse wave velocity (PWV), the central aortic pressures and the augmentation index (Aix) was performed. Univariate and multivariate logistic regression analysis was performed for the examination of the potential association between the eye imaging variables and the cardiovascular-related variables. The odds ratios (OR) with the respective 95% confidence intervals (CI) were calculated. A p-value < 0.05 was considered statistically significant. Patients with DM presented significantly higher PBR5-25 compared to controls without DM (p = 0.023). At the univariate analysis, increased PBR5-25 (≥2.19 μm vs. <2.19 μm) was associated with decreased peripapillary VD at the superior quadrant (univariate OR (95% CI) = 0.34 (0.12-0.93), p = 0.037). Multivariate logistic regression analysis showed that increased PWV (≥13.7 m/s vs. <13.7 m/s) was associated with an increased foveal avascular zone (FAZ) area on OCT-A (p = 0.044) and increased FAZ perimeter (p = 0.048). Moreover, increased Aix (≥14.745% vs. <14.745%) was associated with diabetic macular edema (DME) presence (p = 0.050) and increased perifoveal and parafoveal superior and temporal thickness on OCT (p < 0.05 for all associations). Markers of endothelial damage and arterial stiffness were associated with structural and microvascular retinal alterations in patients with DM, pointing out that OCT-A could be a useful biomarker for detecting potential cardiovascular risk in such patients.

Super-resolution ultrasound imaging reveals temporal cerebrovascular changes with disease progression in female 5×FAD mouse model of Alzheimer's disease: correlation with pathological impairments

Vascular dysfunction is closely associated with the progression of Alzheimer's disease (AD). A critical research gap exists that no studies have explored the invivo temporal changes of cerebrovascular alterations with AD progression in mouse models, encompassing both structure and flow dynamics at micron-scale resolution across the early, middle, and late stages of the disease. In this study, ultrasound localisation microscopy (ULM) was applied to image the cerebrovascular alterations of the transgenic female 5×FAD mouse model across different stages of disease progression: early (4 months), moderate (7 months), and late (12 months). Age-matched non-transgenic (non-Tg) littermates were used as controls. Immunohistology examinations were performed to evaluate the influence of disease progression on the β-amyloid (Aβ) load and microvascular alterations, including morphological changes and the blood-brain barrier (BBB) leakage. Our findings revealed a significant decline in both vascular density and flow velocity in the retrosplenial cortex of 5×FAD mice at an early stage, which subsequently became more pronounced in the visual cortex and hippocampus as the disease progressed. Additionally, we observed a reduction in vascular length preceding diminished flow velocities in cortical penetrating arterioles during the early stages. The quantification of vascular metrics derived from ULM imaging showed significant correlations with those obtained from vascular histological images. Immunofluorescence staining identified early vascular abnormalities in the retrosplenial cortex. As the disease advanced, there was an exacerbation of Aβ accumulation and BBB disruption in a regionally variable manner. The vascular changes observed through ULM imaging exhibited a negative correlation with amyloid load and were associated with the compromise of the BBB integrity. Through high-resolution, invivo imaging of cerebrovasculature, this study reveals significant spatiotemporal dysfunction in cerebrovascular dynamics accompanying disease progression in a mouse model of AD, enhancing our understanding of its pathophysiology. This study is supported by grants from National Key Research and Development Program of China (2020YFA0908800), National Natural Science Foundation of China (12074269, 82272014, 82327804, 62071310), Shenzhen Basic Science Research (20220808185138001, JCYJ20220818095612027, JCYJ20210324093006017), STI 2030-Major Projects (2021ZD0200500) and Guangdong Natural Science Foundation (2024A1515012591, 2024A1515011342).

Macular vascular density alteration patterns in paediatric optic neuritis patients with serum MOG antibody positivity detected by optic coherence tomography angiography

PurposeThe retinal microvascular network plays a crucial role in inflammatory injury in paediatric optic neuritis (PON) with serum MOG antibody positivity (MOG + PON). This study compared retinal microvascular densities and structural alterations in MOG + PON eyes with paediatric isolated optic neuritis (PION) eyes and followed up with the final best-corrected visual acuity (BCVA) after 6 months. MethodsA total of 29 children (52 eyes) with PON, including 15 MOG + PON cases (28 eyes), 6 PION cases (10 eyes), 2 neuromyelitis optica spectrum disorders associated PON(NMOSD-PON) cases (4 eyes), 6 MOG-associated disease (MOGAD) patients without ON-affected eyes (MOG + NPON) cases (10 eyes) and age- and gender-matched healthy controls (HCs) underwent superficial/deep retinal angiography density (SAD/DAD) by optical coherence tomography angiography (OCTA). Their BCVAs were followed up until 6 months after PON onsets. ResultsMOG + PON cases had better final BCVAs than PION and NMOSD-ON. MOG + PON (35.7 ± 10.3 %) and PION (40.1 ± 10.3 %) eyes experienced severe SAD reductions in contrast to MOGAD+NPON (48.7 ± 5.2 %) and HCs eyes (55.6 ± 8.2 %). However, DAD in MOG + PON eyes (48.5 ± 9.2 %) and MOG + NPON eyes (53.1 ± 3.3 %) increased compared to HC eyes (45.7 ± 9.6 %; p = 0.028 and 0.009, respectively). SAD reduction occurred in acute PON and was detected as early as 2 weeks after PON onset. ConclusionsMOG + PON eyes had better final BCVAs than PION eyes, which displayed superficial retinal microvascular perfusion reductions and deep microvascular perfusion increases. SAD could be a sensitive surrogate for PON attacks in children with MOGAD.

Assessment of the impact of low-density lipoprotein cholesterol on retinal vessels using optical coherence tomography angiography

BackgroundLow-density lipoprotein cholesterol (LDL-C) is acknowledged as an independent risk factor (IRF) for atherosclerotic cardiovascular disease. Nevertheless, studies on the impact of LDL-C on microvasculature are still scarce. The retina, abundant in microvasculature, can now be examined for microvascular alterations through the novel, non-invasive, and quantitative optical coherence tomography angiography (OCTA) technique.MethodsIn this cross-sectional study, 243 patients from the geriatric department were recruited (between December 2022 and December 2023). Individuals were classified into four groups based on their LDL-C levels: Group 1 (≤ 1.8 mmol/L), Group 2 (> 1.8 mmol/L to ≤ 2.6 mmol/L), Group 3 (> 2.6 mmol/L to ≤ 3.4 mmol/L), and Group 4 (> 3.4 mmol/L). The OCTA results including retinal vessel density (VD), foveal avascular zone (FAZ) area, macula thickness, and retinal nerve fiber layer (RNFL) thickness were contrasted across these groups. T-tests, analysis of variance, Welch’s tests, or rank-sum tests were employed for statistical comparisons. In cases where significant differences between groups were found, post-hoc multiple comparisons or rank-sum tests were performed for pairwise group comparisons. Spearman’s correlation coefficient was employed to perform bivariate correlation analysis to evaluate the relationship between LDL-C levels and various OCTA measurements. Multivariable regression analysis was used to evaluate the association between LDL-C levels and various OCTA measurements. Linear regression analysis or mixed-effects linear models were applied.ResultsIt was discovered that individuals with LDL-C levels exceeding 2.6 mmol/L (Groups 3 and 4) exhibited reduced VD in the retina, encompassing both the optic disc and macular regions, compared to those with LDL-C levels at or below 2.6 mmol/L (Groups 1 and 2). A negative correlation among LDL-C levels and retinal VD was identified, with r values spanning from − 0.228 to -0.385. Further regression analysis presented β values between − 0.954 and − 2.378. Additionally, no notable disparities were detected among the groups regarding FAZ area, macular thickness, and RNFL thickness.ConclusionsThe outcomes of this study suggest that elevated LDL-C levels constitute an IRF for decreased VD across the entire retina.Trial registrationNCT05644548, December 1, 2022.

Eye Deep-Net: a deep neural network-based multi-class retinal disease diagnostic

Ophthalmologists rely heavily on retinal pictures to diagnose a wide range of eye conditions. Numerous retinal disorders may lead to microvascular alterations in the retina, and a number of studies have been conducted on the early identification of medical pictures to enable prompt and appropriate treatment. In order to identify various eye illnesses using color fundus pictures, this study develops a non-invasive, automated deep learning system. A multiclass ocular illness A productive diagnostic approach was created using the Remind dataset. A variety of augmentation strategies were used to make the structure robust in real-time after multi-class fundus pictures were collected from a multi-label dataset. Low computational demand images were processed in accordance with the network. The fundamental convolutional neural network (CNN) extracts appropriate characteristics from the input color fundus image dataset, and then processed characteristics were employed to make predictive diagnoses. This multi-layer neural network, called Eye Deep-Net, has been developed for training and evaluating images for the recognition of various eye problems. The performance of the suggested model is determined to be much better than numerous baseline state-of-the-art models. The strength from the Eye Deep-Net is assessed using different statistical metrics. The suggested methodology's effectiveness in classifying and identifying diseases using digital fundus pictures is shown by a thorough comparison with the most modern techniques.

Value of the biomarker soluble tyrosine kinase 1 type fms (sFLT-1) in the diagnosis and prognosis of sepsis: a systematic review

IntroductionThe present systematic review analyses the role of soluble fms-like tyrosine kinase-1 (sFLT-1) as an indirect biomarCker of endothelial dysfunction in sepsis or septic shock from articles published in Pubmed between 2010 and March 2022. Materials and methodsA systematic review of studies studying sFLT-1 monitoring in intensive care units in adults with sepsis or septic shock vs. controls for sepsis diagnosis and prognosis has been carried out (PROSPERO CRD42023412929 Registry). ResultsThe endothelial dysfunction of sepsis is one of the keys to the development of the disease. VEGF binds to sFlt-1 acting as a competitive inhibitor of VEGF signalling in endothelial cells and thus neutralizes its pro-inflammatory effects. Endothelial dysfunction is reflected in increased sFLT-1 levels. High values of sFLT-1 were used for the differential diagnosis of sepsis versus other inflammatory pathologies, septic shock versus other types of shock, were elevated over time, estimation of disease prognosis, correlation with sepsis severity, organ dysfunction, and mortality prediction. ConclusionsIt is evident that sepsis is based on endothelial dysfunction. sFLT-1 is one of the main biomarkers of microvascular alteration and is a predictive diagnostic and prognostic biomarker.

Conjunctival microvascular alteration in patients with coronary artery disease assessed using optical coherence tomographic angiography

BackgroundTo quantify conjunctival microvascular characteristics obtained by optical coherence tomographic angiography (OCTA) and investigate their relationship with the presence and severity of coronary artery disease (CAD). MethodsThis cross-sectional study included 103 consecutive CAD patients confirmed by coronary angiography and 125 non-CAD controls. The temporal conjunctivas along the limbus of each participant were scanned using OCTA. Quantification of conjunctival microvasculature was performed by AngioTool software. The severity of the disease was evaluated using SYNTAX and Gensini scores. ResultsCompared to the controls, the CAD group exhibited significantly lower vessel area density (30.22 ± 3.34 vs. 26.70 ± 4.43 %, p < 0.001), lower vessel length density (6.39 ± 0.77 vs. 5.71 ± 0.89/m, p < 0.001), lower junction density (3.44 ± 0.56 vs. 3.05 ± 0.63/m, p < 0.001), and higher lacunarity (0.11 ± 0.03 vs. 0.14 ± 0.05, p < 0.001). Among all participants, lower vessel area density, lower vessel length density, lower junction density, and higher lacunarity were associated with greater odds of having CAD; the adjusted ORs (95 % confidence intervals) per one SD decrease were 2.71 (1.71, 4.29), 2.51(1.61, 3.90), 2.06 (1.39, 3.05), and 0.36 (0.23, 0.58), respectively. Among CAD patients, junction density was negatively associated with the Gensini score (r = −0.359, p = 0.037) and the Syntax score (r = −0.350, p = 0.042) in women but not in men (p > 0.05). ConclusionsConjunctival microvascular characteristics were significantly associated with the presence of CAD. Junction density significantly associated with the severity of CAD among women patients.

Abstract P229: Neurovascular and Cognitive Dysfunction in Hypertension at the Single-Cell Level

Hypertension (HTN) is the leading cause of vascular cognitive impairment, which has been attributed to altered microvascular regulation, neural network dysfunction and white matter (WM) damage. However, the neurovascular cells and cellular networks through which microvascular alterations lead to neuronal dysfunction and WM damage require elucidation. We employed unbiased single-cell RNA sequencing of the neocortex in 10-week-old C57BL/6 male mice treated with AngII (600ng/kg/min s.c.) or vehicle, to map out the transcriptomic changes induced by HTN. Transcriptomes (3 mice/group) were obtained for 39,451 cells before (day 3 after AngII) and after development of neurovascular and cognitive dysfunction (day 42). Profound transcriptional alterations were already seen at day 3 in venular endothelial cells (EC), GABAergic interneurons expressing neuronal nitric oxide synthase (nNOS), and oligodendrocyte precursors (OPC) (EdgeR; FDR&lt; 0.05, logFC&gt; 2). Gene ontology (GO) analysis (p &lt;0.05) revealed terms consistent with senescence of venular EC, validated by immunolabeling with senescence markers (β-galactosidase, p27, p21, p16). GO also flagged terms reflecting suppression of neuronal NO synthesis and synaptic dysfunction in interneurons, which were confirmed by demonstrating reduced NMDA-evoked NO release in brain slices (20±0.03% Veh vs. 0±0.03% AngII;p&lt;0.0001;n=60 neurons from 5 slices/group) and loss of the vesicular GABA transporter, VGAT. In addition, GO revealed early impairments in OPC differentiation, which could underlie later WM disruption. Consistent with this prediction, transcripts suggestive of impaired myelination were overrepresented at 42 days in mature oligodendrocytes (e.g., Hes5 ), and these WM alterations were confirmed in vivo by an increase in internodal distance (Nav1.6/CASPR) in axons (0.09±0.014 µm 3 Veh vs. 0.16±0.01 µm 3 AngII;n=4/group;p&lt;0.05). Ligand-receptor interaction analysis (CellChat) indicated molecular reprogramming of oligodendrocytes by senescent EC via suppression of signaling promoting myelination (CD39-AdeRA1) and upregulation of signaling arresting OPC development (Endothelin-ER2). These data reveal a previously unappreciated susceptibility of venular EC, OPC and nNOS interneurons to the deleterious effects of AngII HTN, and point to a novel pathogenic interaction between senescent EC and OPC, as well as to early nNOS interneuron dysfunction, the disease relevance and therapeutic potential of which requires validation.

C-peptide: an essential ally in microvascular complications of type 2 diabetes mellitus and obesity

BackgroundIn order to investigate microvascular complications in metabolic diseases, we aimed to investigate cerebral and peripheral microcirculation in relation to peripheral neuropathy and laboratory biomarkers in type 2 diabetes mellitus (T2DM) and obesity.MethodsBased on the degree of neuropathy (NP), study participants (40 T2DM and 30 obese individuals) were classified into no-NP, mild-NP and severe-NP subgroups. After the injection of Technetium-99 m hexamethylpropylene amine oxime, both T2DM and obese participants underwent single-photon emission computed tomography/computed tomography ([99mTc]Tc-HMPAO SPECT/CT) and SPECT-only examinations to assess lower limb and brain perfusion; respectively. Peripheral nerve function was evaluated with a neurometer and glycaemic markers were measured from plasma in both groups.ResultsCompared to the obese individuals, lower extremity perfusion was significantly reduced in the diabetic subjects (p < 0.005), while it showed a positive correlation with C-peptide levels and negative association with HbA1c values. A U-shape pattern of peripheral microcirculation was observed between the NP groups, indicating a surprisingly better perfusion in the severe-NP group than in the mild one, with the highest levels in obese patients. Since changes in the C-peptide levels exhibited a similar U-shaped trend across the NP subgroups, we suggest a positive correlation between C-peptide levels and the extent of peripheral perfusion. Although, C-peptide values and cerebral microcirculation correlated positively (rho = 0.27), brain perfusion did not show any differences neither between the diabetic and the obese patients, nor between the NP subgroups (at p < 0.05).ConclusionsEstablishing the link between neuropathy and peripheral microcirculation, C-peptide seems to be a promising biomarker for the prediction of microvascular alterations in metabolic diseases. Of note, the dominance of metabolic factors over microvascular damage in the development of obesity-related neuropathy should be emphasized as well.

A gender-based analysis of retinal microvascular alterations in patients with diabetes mellitus using OCT angiography

PurposeTo assess the difference in microvascular changes between males and females with diabetes mellitus (DM) without diabetic retinopathy (NoDR) and with mild-to-moderate non-proliferative diabetic retinopathy (NPDR) using Optical Coherence Tomography Angiography (OCT-A). DesignRetrospective cross-sectional study. Methods267 DM patients, 133 females (49.81 %), 111 with NoDR (41.57 %) and 156 NPDR (58.43 %) were included. Foveal-centered 3 × 3 mm OCT-A images corresponding to the superficial (SCP), intermediate (ICP) and deep capillary plexus (DCP), and full retinal (RET) slab were used for analysis. For each slab, FAZ area, perimeter, and circularity index (CI) were determined, following manual delineation of the FAZ; perfusion (PD) and vessel density (VD), fractal dimension (FD), vessel length density (VLD), geometric perfusion deficits (GPD) were also computed. Flow voids (FV) were determined in the choriocapillaris plexus; and perfused capillary density (PCD) in the RET slab. ResultsFemales showed larger FAZ CI in SCP and greater FAZ area and perimeter than males in NPDR group. Males had higher central macular thickness than females in NPDR group. All density metrics at the level of ICP and DCP were affected in the NPDR group with no gender differences. Of note, the same significant findings were found in type 1 DM patients, and not in type 2 DM patients. ConclusionsOur OCT-A findings suggest significant microvascular changes in females with NPDR compared to males, but no such differences in patients without DR. Therefore, gender-related vascular alterations might be present in early stages of DR with potential role.

Skin Microvascular Dysfunction in Type 2 Diabetes Mellitus Using Laser Speckle Contrast Analysis and Association with Carotid Intima-Media Thickness.

Background: It is established that diabetes mellitus (DM) is characterized by increased cardiovascular risk associated with subclinical atherosclerosis as well as microvascular alterations. Laser speckle contrast analysis (LASCA) is an innovative, non-invasive method for assessing skin microvascular function. Objectives: We sought to assess skin microvascular function in patients with type 2 DM and matched controls. Methods: Consecutive patients with DM and individuals matched for age, sex and BMI were included in the study. Skin microvascular perfusion was assessed, using LASCA, during baseline, a 5 min occlusion period and a 5 min reperfusion period. Carotid intima-media thickness (cIMT) was measured as a surrogate marker of macrocirculation. Results: In total, 18 patients with DM and 22 in the control group were enrolled. No statistically significant differences were observed in baseline flux, peak flux and percentage decrease during arterial occlusion. During reperfusion, individuals with DM exhibited a smaller peak magnitude compared to controls (147.0 ± 64.7% vs. 189.4 ± 46.0%, respectively; p < 0.05). Moreover, cIMT was higher in patients with DM compared to controls (0.68 ± 0.09 mm vs. 0.60 ± 0.08 mm, respectively, p < 0.01) and was negatively correlated with skin microvascular reactivity in the univariate analysis. In the multivariate analysis, glucose and office systolic blood pressure levels remained significant predictors of microvascular reactivity. Conclusions: Our study shows that patients with type 2 DM exhibit impaired skin microvascular function compared to controls. Furthermore, glucose levels and blood pressure play a key role in microvascular dysfunction. However, additional studies are needed to address the clinical significance of early microvascular changes in DM.

Relationship between Capillaroscopic Architectural Patterns and Different Variant Subgroups in Fabry Disease: Analysis of Cases from a Multidisciplinary Center.

Anderson-Fabry disease (AFD) is a genetic lysosomal storage disorder caused by mutations in the α-galactosidase A gene, leading to impaired lysosomal function and resulting in both macrovascular and microvascular alterations. AFD patients often exhibit increased intima-media thickness (IMT) and reduced flow-mediated dilation (FMD), indicating non-atherosclerotic arterial thickening and the potential for cardiovascular events. Nailfold capillaroscopy, a non-invasive diagnostic tool, has shown potential in diagnosing and monitoring microcirculatory disorders in AFD, despite limited research. This study evaluates nailfold capillaroscopy findings in AFD patients, exploring correlations with GLA gene variant subgroups (associated with classical or late-onset phenotypes and variants of uncertain significance (VUSs)), and assessing morpho-functional differences between sexes. It aims to determine whether capillaroscopy can assist in the early identification of individuals with multiorgan vascular involvement. A retrospective observational study was conducted with 25 AFD patients from AOUP "G. Rodolico-San Marco" in Catania (2020-2023). Patients underwent genetic testing, enzyme activity evaluation, and nailfold capillaroscopy using Horus basic HS 200 videodermatoscopy. Parameters like angiotectonic disorder, vascular areas, capillary density, and intimal thickening were assessed. The study identified significant differences in capillaroscopy findings among patients with different GLA gene variant subgroups. Classic AFD variant patients showed reduced capillary length and signs of erythrocyte aggregation and dilated subpapillary plexus. No correlation was found between enzymatic activity and capillaroscopy parameters. However, Lyso-Gb3 levels were positively correlated with average capillary length (ῤ = 0.453; p = 0.059). Sex-specific differences in capillaroscopy findings were observed in neoangiogenesis and average capillary length, with distinct implications for men and women. This study highlights the potential of nailfold capillaroscopy in the diagnostic process and clinical management of AFD, particularly in relation to specific GLA gene mutations, as a valuable tool for the early diagnosis and monitoring of AFD.