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Current Opinion in Nephrology and... Mar 2009The prevalence of chronic kidney disease has been growing consistently for the past decades. Renal failure is often associated with defective angiogenesis, and... (Review)
Review
PURPOSE OF REVIEW
The prevalence of chronic kidney disease has been growing consistently for the past decades. Renal failure is often associated with defective angiogenesis, and recognition of the contribution of the renal microcirculation to the progression of chronic renal disease may aid in the development of therapeutic interventions.
RECENT FINDINGS
Intra-renal proliferation, remodeling, and/or rarefaction of microvessels in response to injury can all aggravate nephron damage, and experimental evidence suggests that they may constitute the early steps in the complex pathways involved in progressive renal injury. Recent studies showed the benefits of targeted interventions deemed to promote neovascularization (e.g. progenitor cells, growth factors) on the ischemic myocardium and brain and in a few models of renal disease.
SUMMARY
Evidence of aberrant renal microvascular architecture in various forms of renal disease provides the impetus to attempt modulating the renal microcirculation to interfere with the disease process. Targeted interventions to preserve the renal microcirculation may not only decrease the evolving injury in renal vascular disease but also potentially constitute a coadjuvant intervention to become part of a comprehensive management plan to improve the success of parallel strategies to preserve renal function, such as revascularization.
Topics: Animals; Cell Proliferation; Humans; Kidney; Microcirculation; Neovascularization, Physiologic
PubMed: 19430335
DOI: 10.1097/MNH.0b013e32831ec1db -
Journal of Vascular Surgery Sep 2005Insufficient blood flow through end-resistance arteries leads to symptoms associated with peripheral vascular disease. This may be caused in part by poor... (Review)
Review
Insufficient blood flow through end-resistance arteries leads to symptoms associated with peripheral vascular disease. This may be caused in part by poor macrocirculatory inflow or impaired microcirculatory function. Dysfunction of the microcirculation occurs in a similar fashion in multiple tissue beds long before the onset of atherosclerotic symptoms. Impaired microcirculatory vasodilatation has been shown to occur in certain disease states including peripheral vascular disease, diabetes mellitus, hypercholesterolemia, hypertension, chronic renal failure, abdominal aortic aneurysmal disease, and venous insufficiency, as well as in menopause, advanced age, and obesity. Microcirculatory structure and function can be evaluated with transcutaneous oxygen, pulp skin flow, iontophoresis, and capillaroscopy. We discuss the importance of the microcirculation, investigative methods for evaluating its function, and clinical applications and review the literature of the microcirculation in these different states.
Topics: Humans; Microcirculation; Monitoring, Physiologic; Peripheral Vascular Diseases
PubMed: 16171612
DOI: 10.1016/j.jvs.2005.05.019 -
Revista Medica de Chile Dec 2008Aging produces its own cardiovascular changes, mainly remodelling of arteries, heart and the microcirculation. These progressive changes, detected since adolescence,... (Review)
Review
Aging produces its own cardiovascular changes, mainly remodelling of arteries, heart and the microcirculation. These progressive changes, detected since adolescence, represent a major risk factor for the development of cardiovascular diseases. Remodelling of arteries produces a thickening of the intima-media with fracture of elastic fibers and their replacement by collagen. These alterations induce an increase of the pulse wave and aortic impedance, with greater resistance to ventricular ejection, that in turns induces the remodelling of the left ventricle. Ventricular remodelling leads to systolic, diastolic and chronotropic dysfunctions that explain the reduced capacity of old people to increase cardiac output during exercise. These alterations together with oxidative endothelial dysfunction and somatic mitochondrial mutations in the skeletal muscle decrease aerobic capacity, especially in adults aged >70 years. On the other hand, the transmission of an increased pulse wave to microvessels, mainly of the brain and kidneys, damage these organs. There is a search for candidate genes associated to this phenotype, especially those associated with arterial structure. At present no specific treatment is available for cardiovascular aging. Exercise preserves a better aerobic capacity but does not prevent its decline with age. Vasodilator drugs may decrease aortic impedance and perhaps delay remodelling. However there is no clinical evidence available to recommend these drugs in young healthy people. Finally new drugs that modify aortic molecular structure are been investigated.
Topics: Aging; Blood Vessels; Cardiovascular Physiological Phenomena; Exercise; Humans; Microcirculation; Myocardium
PubMed: 19350177
DOI: No ID Found -
American Journal of Physiology. Heart... Jul 2022Hyperspectral imaging (HSI) provides a fast, reliable, and noninvasive way for the study of vascular microcirculation in animal models. Rapid hyperspectral imaging of...
Hyperspectral imaging (HSI) provides a fast, reliable, and noninvasive way for the study of vascular microcirculation in animal models. Rapid hyperspectral imaging of large portions of the microcirculatory preparation is critical for understanding the function and regulation of vascular microcirculatory networks. This report presents the application of an off-the-shelf benchtop HSI linear scanning system to acquire larger field-of-view images of microcirculatory preparations. The HSI line detector was displaced perpendicular to the scanning direction to map larger areas, with a rate of displacement determined by the scanning rate and the exposure time. Analysis of the collected image was used to assess dynamic changes in the microcirculation. The system records dynamic changes in microvascular hemoglobin oxygen (HbO) saturation and vascular morphology during hypoxia and reoxygenation and has similar acquisition speeds to commonly referenced spectral-scanning HSI systems. In addition, the HbO saturations collected via HSI closely correlate with those collected by phosphorescence quenching microscopy. The reported system enables dynamic functional imaging of the microcirculation for broad experimental and clinical applications. This study presents a novel bench setup and algorithm to measure intravascular hemoglobin oxygen saturation in microcirculation. Wide-field hyperspectral imaging allows for rapid quantification of intravascular changes in hemoglobin saturation. The method described in this manuscript can expand the understanding of oxygen delivery to tissues in vivo.
Topics: Animals; Hemoglobins; Hypoxia; Microcirculation; Microscopy; Oxygen
PubMed: 35522555
DOI: 10.1152/ajpheart.00624.2021 -
Anaesthesiology Intensive Therapy 2015Shock is defined as a state in which the circulation is unable to deliver sufficient oxygen to meet the demands of the tissues, resulting in cellular dysoxia and organ... (Review)
Review
Shock is defined as a state in which the circulation is unable to deliver sufficient oxygen to meet the demands of the tissues, resulting in cellular dysoxia and organ failure. In this process, the factors that govern the circulation at a haemodynamic level and oxygen delivery at a microcirculatory level play a major role. This manuscript aims to review the blood flow regulation from macro- and micro-haemodynamic point of view and to discuss new potential therapeutic approaches for cardiovascular instability in patients in cardiovascular shock. Despite the recent advances in haemodynamics, the mechanisms that control the vascular resistance and the venous return are not fully understood in critically ill patients. The physical properties of the vascular wall, as well as the role of the mean systemic filling pressure are topics that require further research. However, the haemodynamics do not totally explain the physiopathology of cellular dysoxia, and several factors such as inflammatory changes at the microcirculatory level can modify vascular resistance and tissue perfusion. Cellular vasoactive mediators and endothelial and glucocalix damage are also involved in microcirculatory impairment. All the levels of the circulatory system must be taken into account. Evaluation of microcirculation may help one to detect under-diagnosed shock, and together with classic haemodynamics, guide one towards the appropriate therapy. Restoration of classic haemodynamic parameters is essential but not sufficient to detect and treat patients in cardiovascular shock.
Topics: Cardiac Output; Glomerular Filtration Rate; Homeostasis; Humans; Microcirculation; Renal Circulation; Shock
PubMed: 26588480
DOI: 10.5603/AIT.a2015.0077 -
Microcirculation (New York, N.Y. : 1994) May 2014In the adult, angiogenesis leads to an expanded microvascular network as new vessel segments are added to an existing microcirculation. Necessarily, growing neovessels... (Review)
Review
In the adult, angiogenesis leads to an expanded microvascular network as new vessel segments are added to an existing microcirculation. Necessarily, growing neovessels must navigate through tissue stroma as they locate and grow toward other vessel elements. We have a growing body of evidence demonstrating that angiogenic neovessels reciprocally interact with the interstitial matrix of the stroma resulting in directed neovascular growth during angiogenesis. Given the compliance and the viscoelastic properties of collagen, neovessel guidance by the stroma is likely due to compressive strain transverse to the direction of primary tensile forces present during active tissue deformation. Similar stromal strains control the final network topology of the new microcirculation, including the distribution of arterioles, capillaries, and venules. In this case, stromal-derived stimuli must be present during the post-angiogenesis remodeling and maturation phases of neovascularization to have this effect. Interestingly, the preexisting organization of vessels prior to the start of angiogenesis has no lasting influence on the final, new network architecture. Combined, the evidence describes interplay between angiogenic neovessels and stroma that is important in directed neovessel growth and invasion. This dynamic is also likely a mechanism by which global tissue forces influence vascular form and function.
Topics: Adult; Animals; Humans; Microcirculation; Microvessels; Neovascularization, Physiologic; Stromal Cells
PubMed: 24447042
DOI: 10.1111/micc.12115 -
Intensive Care Medicine Mar 2009
Topics: Emergency Medical Services; Hemorrhage; Humans; Hypovolemia; Microcirculation; Shock, Hemorrhagic
PubMed: 19125231
DOI: 10.1007/s00134-008-1386-z -
Microcirculation (New York, N.Y. : 1994) Feb 2012Xenobiotic particles can be considered in two genres: air pollution particulate matter and engineered nanoparticles. Particle exposures can occur in the greater... (Review)
Review
Xenobiotic particles can be considered in two genres: air pollution particulate matter and engineered nanoparticles. Particle exposures can occur in the greater environment, the workplace, and our homes. The majority of research in this field has, justifiably, focused on pulmonary reactions and outcomes. More recent investigations indicate that cardiovascular effects are capable of correlating with established mortality and morbidity epidemiological data following particle exposures. While the preliminary and general cardiovascular toxicology has been defined, the mechanisms behind these effects, specifically within the microcirculation, are largely unexplored. Therefore, the purpose of this review is several fold: first, a historical background on toxicological aspects of particle research is presented. Second, essential definitions, terminology, and techniques that may be unfamiliar to the microvascular scientist will be discussed. Third, the most current concepts and hypotheses driving cardiovascular research in this field will be reviewed. Lastly, potential future directions for the microvascular scientist will be suggested. Collectively speaking, microvascular research in the particle exposure field represents far more than a "niche." The immediate demand for basic, translational, and clinical studies is high and diverse. Microvascular scientists at all career stages are strongly encouraged to expand their research interests to include investigations associated with particle exposures.
Topics: Animals; Cardiovascular Diseases; Humans; Microcirculation; Particulate Matter; Xenobiotics
PubMed: 21951337
DOI: 10.1111/j.1549-8719.2011.00137.x -
Microcirculation (New York, N.Y. : 1994) Nov 2012Vascular compromise and the accompanying perfusion deficits cause or complicate a large array of disease conditions and treatment failures. This has prompted the... (Review)
Review
Vascular compromise and the accompanying perfusion deficits cause or complicate a large array of disease conditions and treatment failures. This has prompted the exploration of therapeutic strategies to repair or regenerate vasculatures, thereby establishing more competent microcirculatory beds. Growing evidence indicates that an increase in vessel numbers within a tissue does not necessarily promote an increase in tissue perfusion. Effective regeneration of a microcirculation entails the integration of new stable microvessel segments into the network via neovascularization. Beginning with angiogenesis, neovascularization entails an integrated series of vascular activities leading to the formation of a new mature microcirculation, and includes vascular guidance and inosculation, vessel maturation, pruning, AV specification, network patterning, structural adaptation, intussusception, and microvascular stabilization. While the generation of new vessel segments is necessary to expand a network, without the concomitant neovessel remodeling and adaptation processes intrinsic to microvascular network formation, these additional vessel segments give rise to a dysfunctional microcirculation. While many of the mechanisms regulating angiogenesis have been detailed, a thorough understanding of the mechanisms driving post-angiogenesis activities specific to neovascularization has yet to be fully realized, but is necessary to develop effective therapeutic strategies for repairing compromised microcirculations as a means to treat disease.
Topics: Animals; Humans; Microcirculation; Microvessels; Neovascularization, Physiologic; Regeneration
PubMed: 22734666
DOI: 10.1111/j.1549-8719.2012.00207.x -
Critical Care (London, England) 2010Despite diagnostic and therapeutic improvements, mortality rates in patients with cardiogenic shock remain relatively high. Several studies showed that cardiogenic shock... (Review)
Review
Despite diagnostic and therapeutic improvements, mortality rates in patients with cardiogenic shock remain relatively high. Several studies showed that cardiogenic shock is associated with alterations in the microvascular circulation. These alterations may be reversed by extracorporeal support devices. A study by Munsterman and colleagues adds to the body of evidence showing that in patients deemed ready for discontinuing intra-aortic balloon pump (IABP) support, microcirculatory flow in small vessels increases after ceasing IABP therapy. This study not only highlights the need for optimal timing of weaning from IABP support but also supports recent findings that global hemodynamics do not necessarily result in changes of microvascular perfusion. All modalities of modern treatment in cardiogenic shock need to be evaluated for their effect on the microcirculation. Microcirculatory evaluations should be part of randomized controlled trial protocols. More effort is needed to improve outcomes and understand the microcirculation as a therapy target and not as a silent bystander.
Topics: Animals; Cardiotonic Agents; Drug Delivery Systems; Extracorporeal Circulation; Humans; Intra-Aortic Balloon Pumping; Microcirculation; Randomized Controlled Trials as Topic; Shock, Cardiogenic
PubMed: 20828425
DOI: 10.1186/cc9244