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Capillary Recruitment (capillary + recruitment)
Selected AbstractsReal-Time Contrast Imaging: A New Method to Monitor Capillary Recruitment in Human Forearm Skeletal MuscleMICROCIRCULATION, Issue 3 2008Alexandra H. Mulder ABSTRACT Objective: Muscle capillary perfusion can be measured by contrast-enhanced ultrasound. We examined whether a less time-consuming ultrasound technique, called "real-time imaging," could be used to measure capillary recruitment in human forearm skeletal muscle. Methods: We measured microvascular blood volume and microvascular flow velocity using bolus injections of contrast microbubbles after forearm muscle exercise and a two-hour infusion of insulin into the brachial artery (both associated with capillary recruitment) and after sodium nitroprusside infusion (no changes in flow distribution). Results: After an intravenous bolus injection of the contrast agent, the steady-state concentration of contrast agent in forearm muscle lasted long enough (approximately 190 seconds) for the duration of the measurements (which take 70,80 seconds), rendering the continuous infusion of microbubbles unnecessary. Microvascular blood-volume measurements showed a good short-time reproducibility and a good reproducibility after repositioning of the forearm. Reproducibility of microvascular flow velocity was too low. Exercise and insulin infusion both increased microvascular blood volume, consistent with capillary recruitment. Sodium nitroprusside had no effect. Conclusion: Real-time contrast imaging, after bolus injections of an ultrasound contrast agent, provides reliable information about capillary recruitment in human forearm skeletal muscle, and may offer a valuable tool in studying human (patho)physiology. [source] Obesity, Insulin Resistance, and Capillary RecruitmentMICROCIRCULATION, Issue 4-5 2007Stephen Rattigan ABSTRACT Objective: Insulin has vascular actions within the skeletal muscle microcirculation (capillary recruitment) that enhance its own access and that of glucose to the muscle cells. Obesity and insulin resistance are associated with dysregulated vascular function within muscle and a loss of insulin-mediated capillary recruitment. Furthermore, agents that impair insulin's vascular actions to recruit capillaries lead to acute insulin resistance in terms of muscle glucose uptake. Together these data suggest a strong connection between the loss of insulin-mediated capillary recruitment and the development of insulin resistance. This review examines the mechanisms involved in insulin-mediated capillary recruitment and the vascular defects associated with obesity and insulin resistance that may impair the capillary recruiting process. Understanding the mechanisms of insulin-mediated capillary recruitment and its impairment may lead to new treatment avenues to prevent the progression of obesity to diabetes. [source] Individuals at increased coronary heart disease risk are characterized by an impaired microvascular function in skinEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2003R. G. IJzerman Abstract Background To investigate whether microvascular function in skin is a valid model to study the relationships between cardiovascular risk factors and microvascular function, we investigated skin microvascular function in individuals with increased coronary heart disease (CHD) risk. Materials and methods Forty-six healthy White individuals aged 30,70 years were studied. Coronary heart disease risk was assessed with the use of the CHD risk score according to the Framingham Heart Study, which is based on the risk factors age, blood pressure, cigarette smoking, total cholesterol, HDL cholesterol and diabetes. Endothelium-dependent and -independent vasodilation in skin were evaluated with laser Doppler after iontophoresis of acetylcholine and sodium nitroprusside. Videomicroscopy was used to measure recruitment of skin capillaries after arterial occlusion. Results Coronary heart disease risk score (i.e. the 10-year probability of CHD) varied from 1,37%. Microvascular function decreased with increasing quartiles of CHD risk (for acetylcholine-mediated vasodilation: 687, 585, 420 and 326%, P = 0·002; for nitroprusside-mediated vasodilation: 776, 582, 513 and 366%, P = 0·02; for capillary recruitment: 49·9, 44·6, 27·2 and 26·7%, P = 0·001). These trends were similar in men and women (P for interaction > 0·2) and independent of body mass index. Conclusions Increased CHD risk is associated with an impaired endothelium-dependent vasodilatation and capillary recruitment in skin, suggesting that microvascular function in skin is a valid model to study the relationships between cardiovascular risk factors and microvascular function. [source] Real-Time Contrast Imaging: A New Method to Monitor Capillary Recruitment in Human Forearm Skeletal MuscleMICROCIRCULATION, Issue 3 2008Alexandra H. Mulder ABSTRACT Objective: Muscle capillary perfusion can be measured by contrast-enhanced ultrasound. We examined whether a less time-consuming ultrasound technique, called "real-time imaging," could be used to measure capillary recruitment in human forearm skeletal muscle. Methods: We measured microvascular blood volume and microvascular flow velocity using bolus injections of contrast microbubbles after forearm muscle exercise and a two-hour infusion of insulin into the brachial artery (both associated with capillary recruitment) and after sodium nitroprusside infusion (no changes in flow distribution). Results: After an intravenous bolus injection of the contrast agent, the steady-state concentration of contrast agent in forearm muscle lasted long enough (approximately 190 seconds) for the duration of the measurements (which take 70,80 seconds), rendering the continuous infusion of microbubbles unnecessary. Microvascular blood-volume measurements showed a good short-time reproducibility and a good reproducibility after repositioning of the forearm. Reproducibility of microvascular flow velocity was too low. Exercise and insulin infusion both increased microvascular blood volume, consistent with capillary recruitment. Sodium nitroprusside had no effect. Conclusion: Real-time contrast imaging, after bolus injections of an ultrasound contrast agent, provides reliable information about capillary recruitment in human forearm skeletal muscle, and may offer a valuable tool in studying human (patho)physiology. [source] Obesity, Insulin Resistance, and Capillary RecruitmentMICROCIRCULATION, Issue 4-5 2007Stephen Rattigan ABSTRACT Objective: Insulin has vascular actions within the skeletal muscle microcirculation (capillary recruitment) that enhance its own access and that of glucose to the muscle cells. Obesity and insulin resistance are associated with dysregulated vascular function within muscle and a loss of insulin-mediated capillary recruitment. Furthermore, agents that impair insulin's vascular actions to recruit capillaries lead to acute insulin resistance in terms of muscle glucose uptake. Together these data suggest a strong connection between the loss of insulin-mediated capillary recruitment and the development of insulin resistance. This review examines the mechanisms involved in insulin-mediated capillary recruitment and the vascular defects associated with obesity and insulin resistance that may impair the capillary recruiting process. Understanding the mechanisms of insulin-mediated capillary recruitment and its impairment may lead to new treatment avenues to prevent the progression of obesity to diabetes. [source] Vasomotion and insulin-mediated capillary recruitment , part of the explanation?THE JOURNAL OF PHYSIOLOGY, Issue 14 2009Geraldine F. Clough No abstract is available for this article. [source] | ||||||||||