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European Neurology 2023The no-reflow phenomenon refers to a failure to restore normal cerebral microcirculation despite brain large artery recanalization after acute ischemic stroke, which was... (Review)
Review
BACKGROUND
The no-reflow phenomenon refers to a failure to restore normal cerebral microcirculation despite brain large artery recanalization after acute ischemic stroke, which was observed over 50 years ago.
SUMMARY
Different mechanisms contributing to no-reflow extend across the endovascular, vascular wall, and extravascular factors. There are some clinical tools to evaluate cerebral microvascular hemodynamics and represent biomarkers of the no-reflow phenomenon. As substantial experimental and clinical data showed that clinical outcome was better correlated with reperfusion status rather than recanalization in patients with ischemic stroke, how to address the no-reflow phenomenon is critical. But effective treatments for restoring cerebral microcirculation have not been well established until now, so there is an urgent need for novel therapeutic perspectives to improve outcomes after recanalization therapies.
CONCLUSION
Here, we review the occurrence of the no-reflow phenomenon after ischemic stroke and discuss its impact, detection method, and therapeutic strategies on the course of ischemic stroke, from basic science to clinical findings.
Topics: Humans; Ischemic Stroke; Microcirculation; No-Reflow Phenomenon; Brain; Treatment Outcome; Stroke
PubMed: 36617418
DOI: 10.1159/000528250 -
Disease Markers 2022Bulbar conjunctival microcirculation is a microvascular system distributed in the translucent bulbar conjunctiva near the corneal limbus. Multiple ocular diseases lead... (Review)
Review
Bulbar conjunctival microcirculation is a microvascular system distributed in the translucent bulbar conjunctiva near the corneal limbus. Multiple ocular diseases lead to bulbar conjunctival microcirculation alterations, which means that bulbar conjunctival microcirculation alterations would be potential screening and diagnostic indicators for these ocular diseases. In recent years, with the emergence and application of a variety of noninvasive observation devices for bulbar conjunctiva microcirculation and new image processing technologies, studies that explored the potential of bulbar conjunctival microcirculation alterations in the diagnosis of ocular diseases have been emerging. However, the potential of bulbar conjunctival microcirculation alterations as indicators for ocular diseases has not been exploited to full advantage. The observation devices, image processing methods, and algorithms are not unified. And large-scale research is needed to concrete bulbar conjunctival microcirculation alterations as indicators for ocular diseases. In this paper, we provide an update on the progress of bulbar conjunctival microcirculation alterations in the diagnosis of ocular diseases in recent five years (from January 2017 to March 2022). Relevant ocular diseases include contact lens wearing, dry eye, conjunctival malignant melanoma, conjunctival nevus, and diabetic retinopathy.
Topics: Conjunctiva; Humans; Microcirculation
PubMed: 36072898
DOI: 10.1155/2022/4046809 -
Microcirculation (New York, N.Y. : 1994) Oct 2022The aim of this study was to describe possible remodeling (i.e., dilatation and elongation) of papillary capillaries induced by increased oxygen demand for the repair...
OBJECTIVE
The aim of this study was to describe possible remodeling (i.e., dilatation and elongation) of papillary capillaries induced by increased oxygen demand for the repair process following a skin wound.
METHODS
Computer-assisted video microscopy was used to examine 10 healthy volunteers before (baseline) and after (≈1 h and ≈24 h) an incision (5 mm long and 1 mm deep) on the forearm, 0-1 mm and 30 mm (control site) from the incision. We defined categories from 0 (low) to 3 (high) to grade dilatation and elongation of the nutritive papillary capillaries, as well as the visibility of the superficial vascular plexus. Approximately 10 000 capillaries from 200 films were scored.
RESULTS
The nutritive papillary capillaries were dilated and elongated (p < 0.01) after ≈24 h; that is, elongation (score 1.9 ± 0.9) vs baseline (score 0.9 ± 0.6), p < 0.01 and dilatation (score 2.2 ± 0.7) vs baseline (score 0.3 ± 0.3), p < 0.01. Superficial plexus visibility increased (p < 0.01) after ≈1 h (score 2.0 ± 0.7) and ≈24 h (score 2.7 ± 0.3) vs baseline (score 0.8 ± 0.4).
CONCLUSION
The superficial vascular skin plexus showed enhanced visibility already ≈1 h after the skin trauma. Morphological remodeling in the nutritive papillary capillaries-dilatation and elongation after ≈24 h-facilitate increased O supply.
Topics: Humans; Microcirculation; Capillaries; Skin; Microscopy, Video; Forearm
PubMed: 35231135
DOI: 10.1111/micc.12755 -
Interventional Cardiology Clinics Jan 2023Coronary microvascular dysfunction (CMD) is a common cause of ischemia but no obstructive coronary artery disease that results in an inability of the coronary... (Review)
Review
Coronary microvascular dysfunction (CMD) is a common cause of ischemia but no obstructive coronary artery disease that results in an inability of the coronary microvasculature to meet myocardial oxygen demand. CMD is challenging to diagnose and manage due to a lack of mechanistic research and targeted therapy. Recent evidence suggests we can improved patient outcomes by stratifying antianginal therapies according to the diagnosis revealed by invasive assessment of the coronary microcirculation. This review article appraises the evidence for management of CMD, which includes treatment of cardiovascular risk, antianginal therapy and therapy for atherosclerosis.
Topics: Humans; Coronary Circulation; Microcirculation; Coronary Artery Disease; Myocardial Ischemia
PubMed: 36372457
DOI: 10.1016/j.iccl.2022.09.011 -
Arteriosclerosis, Thrombosis, and... Jan 2020
Topics: Coronary Stenosis; Humans; Microcirculation; Myocardial Ischemia
PubMed: 31869270
DOI: 10.1161/ATVBAHA.119.313579 -
Annual Review of Physiology Feb 2023Resistance arteries and arterioles evolved as specialized blood vessels serving two important functions: () regulating peripheral vascular resistance and blood pressure... (Review)
Review
Resistance arteries and arterioles evolved as specialized blood vessels serving two important functions: () regulating peripheral vascular resistance and blood pressure and () matching oxygen and nutrient delivery to metabolic demands of organs. These functions require control of vessel lumen cross-sectional area (vascular tone) via coordinated vascular cell responses governed by precise spatial-temporal communication between intracellular signaling pathways. Herein, we provide a contemporary overview of the significant roles that redox switches play in calcium signaling for orchestrated endothelial, smooth muscle, and red blood cell control of arterial vascular tone. Three interrelated themes are the focus: () smooth muscle to endothelial communication for vasoconstriction, () endothelial to smooth muscle cell cross talk for vasodilation, and () oxygen and red blood cell interregulation of vascular tone and blood flow. We intend for this thematic framework to highlight gaps in our current knowledge and potentially spark interest for cross-disciplinary studies moving forward.
Topics: Humans; Microcirculation; Vasodilation; Vasoconstriction; Oxidation-Reduction; Oxygen
PubMed: 36763969
DOI: 10.1146/annurev-physiol-031522-021457 -
European Heart Journal Aug 2023
Topics: Humans; Prognosis; Microcirculation; Heart; Coronary Circulation
PubMed: 37358487
DOI: 10.1093/eurheartj/ehad291 -
JACC. Cardiovascular Imaging Aug 2019
Topics: Humans; Microcirculation; Percutaneous Coronary Intervention; ST Elevation Myocardial Infarction
PubMed: 31395247
DOI: 10.1016/j.jcmg.2019.06.008 -
Experimental Physiology Sep 2020What is the topic of this review? We describe a range of techniques in the time, frequency and information domains and their application alone and together for the... (Review)
Review
NEW FINDINGS
What is the topic of this review? We describe a range of techniques in the time, frequency and information domains and their application alone and together for the analysis of blood flux signals acquired using laser Doppler fluximetry. What advances does it highlight? This review highlights the idea of using quantitative measures in different domains and scales to gain a better mechanistic understanding of the complex behaviours in the microcirculation.
ABSTRACT
To date, time- and frequency-domain metrics of signals acquired through laser Doppler fluximetry have been unable to provide consistent and robust measures of the changes that occur in the microcirculation in healthy individuals at rest or in response to a provocation, or in patient cohorts. Recent studies have shown that in many disease states, such as metabolic and cardiovascular disease, there appears to be a reduction in the adaptive capabilities of the microvascular network and a consequent reduction in physiological information content. Here, we introduce non-linear measures for assessing the information content of fluximetry signals and demonstrate how they can yield deeper understanding of network behaviour. In addition, we show how these methods may be adapted to accommodate the multiple time scales modulating blood flow and how they can be used in combination with time- and frequency-domain metrics to discriminate more effectively between the different mechanistic influences on network properties.
Topics: Humans; Laser-Doppler Flowmetry; Microcirculation; Microvessels; Regional Blood Flow; Skin
PubMed: 31875329
DOI: 10.1113/EP087874 -
Journal of Cerebral Blood Flow and... Oct 2023Temporal lobe epilepsy (TLE) is increasingly associated with blood-brain barrier dysfunction and microvascular alterations, yet the pathophysiological link is missing....
Temporal lobe epilepsy (TLE) is increasingly associated with blood-brain barrier dysfunction and microvascular alterations, yet the pathophysiological link is missing. An important barrier function is exerted by the glycocalyx, a gel-like layer coating the endothelium. To explore such associations, we used intraoperative videomicroscopy to quantify glycocalyx and microcirculation properties of the neocortex and hippocampus of 15 patients undergoing resective brain surgery as treatment for drug-resistant TLE, and 15 non-epileptic controls. Fluorescent lectin staining of neocortex and hippocampal tissue was used for blood vessel surface area quantification. Neocortical perfused boundary region, the thickness of the glycocalyx' impaired layer, was higher in patients (2.64 ± 0.52 µm) compared to controls (1.31 ± 0.29 µm), 0.01, indicative of reduced glycocalyx integrity in patients. Moreover, erythrocyte flow velocity analysis revealed an impaired ability of TLE patients to (de-)recruit capillaries in response to changing metabolic demands ( = 0.75, 0.01), indicating failure of neurovascular coupling mechanisms. Blood vessel quantification comparison between intraoperative measurements and resected tissue showed strong correlation ( = 0.94, 0.01). This is the first report on assessment of glycocalyx and microcirculation properties in TLE patients, confirming the pivotal role of cerebrovascular changes. Further assessment of the cerebral microcirculation in relation to epileptogenesis might open avenues for new therapeutic targets for drug-resistant epilepsy.
Topics: Humans; Epilepsy, Temporal Lobe; Glycocalyx; Microcirculation; Blood-Brain Barrier; Capillaries
PubMed: 37231664
DOI: 10.1177/0271678X231179413