Changes In Skin Microcirculation Research Articles

The acute adaptation of skin microcirculatory perfusion in vivo does not involve a local response but rather a centrally mediated adaptive reflex.

Introduction: Cardiovascular homeostasis involves the interaction of multiple players to ensure a permanent adaptation to each organ's needs. Our previous research suggested that changes in skin microcirculation-even if slight and distal-always evoke an immediate global rather than "local" response affecting hemodynamic homeostasis. These observations question our understanding of known reflexes used to explore vascular physiology, such as reactive hyperemia and the venoarteriolar reflex (VAR). Thus, our study was designed to further explore these responses in older healthy adults of both sexes and to potentially provide objective evidence of a centrally mediated mechanism governing each of these adaptive processes. Methods: Participants (n = 22, 52.5 ± 6.2 years old) of both sexes were previously selected. Perfusion was recorded in both feet by laser Doppler flowmetry (LDF) and photoplethysmography (PPG). Two different maneuvers with opposite impacts on perfusion were applied as challengers to single limb reactive hyperemia evoked by massage and a single leg pending to generate a VAR. Measurements were taken at baseline (Phase I), during challenge (Phase II), and recovery (Phase III). A 95% confidence level was adopted. As proof of concept, six additional young healthy women were selected to provide video imaging by using optoacoustic tomography (OAT) of suprasystolic post-occlusive reactive hyperemia (PORH) in the upper limb. Results: Modified perfusion was detected by LDF and PPG in both limbs with both hyperemia and VAR, with clear systemic hemodynamic changes in all participants. Comparison with data obtained under the same conditions in a younger cohort, previously published by our group, revealed that results were not statistically different between the groups. Discussion: The OAT documentary and analysis showed that the suprasystolic pressure in the arm changed vasomotion in the forearm, displacing blood from the superficial to the deeper plexus vessels. Deflation allowed the blood to return and to be distributed in both plexuses. These responses were present in all individuals independent of their age. They appeared to be determined by the need to re-establish hemodynamics acutely modified by the challenger, which means that they were centrally mediated. Therefore, a new mechanistic interpretation of these exploratory maneuvers is required to better characterize in vivo cardiovascular physiology in humans.

Skin endothelial cell and microcirculation function study in recurred keloids patients after keloid surgery and radiotherapy.

Keloid is a type of benign tumor of the skin with abnormal proliferation of fibrous tissue. We sought to observe the changes in skin microcirculation and endothelial cell function around the recurred keloid and explore the skin microcirculation characters in recurred keloid patients. Six patients with recurred keloid were treated with keloid surgery and radiotherapy for the second time. Microcirculation of recurred keloids and their surrounding normal skin tissue was observed with laser Doppler flowmeter before operation. Expression of vascular endothelial growth factor (VEGF), CD31, and HIF-1α were identified by several assay. The local blood flow of group RN was enhanced. The average strength of group N is 0.87. The average strength of group RN is 2.08. The expression of VEGF, CD31, and hypoxia inducible factor-1α (HIF-1α) protein in the keloid-recurred skin (RN) group was higher than the normal skin group via immunohistochemistry (IHC) and Western blotting analysis. The relative expression of VEGF and CD31 mRNA was significantly increased in RN group samples (P < .05). There are significant differences in the expression of VEGF, CD31, and HIF-1α in the recurred keloid skin after radiotherapy and normal skin. They may be used as potential biomarkers and targets for future research on keloid recurrence.

The state of capillary microcirculation in patients with diabetes mellitus

Objective — to study endothelial alterations at the level of the microcirculatory section of the blood circulation system in patients with diabetes mellitus by using capillaroscopy in the comprehensive examination.&#x0D; Materials and methods. The clinical examination was performed with the involvement of 37 patients with type 1 and type 2 diabetes mellitus, aged 21 to 65 years, with various manifestations and severity of the disease. The patients have been assigned into two groups. The first group (control) consisted of 12 patients without diabetes, the second group (study group) included 37 patients with type 1 and type 2 diabetes mellitus. The state of the microcirculatory bed of the lower extremities was estimated using capillaroscopy by the Dino‑Lite MEDL4N5 Pro capillaroscope (Netherlands).&#x0D; Results. The analysis of indicators of skin microcirculation showed that both quantitative and qualitative changes in skin microcirculation were observed in patients with diabetes mellitus compared to the control group. The color of the background changed from pale pink to deep red, and with a severe form it even had a grayish tint. Various changes in the size and shape of capillaries and capillary loops have been registered, indicating the processes of capillary destruction and neoangiogenesis. The structural changes of the capillaries were especially prominent with clinically pronounced symptoms. The most frequent changes detected were the spiral‑twisted capillaries. The pattern of the venous network was more pronounced; the spastic altered and shortened arterial genua were conjoined with dilated and tortuous venous ones; aneurysmal dilatations and arterio‑venous anastomoses were common. In addition, the capillaroscopic examination makes it possible to observe a decrease in the number of capillaries, which is expressed in varying degrees, up to the formation of so‑called avascular areas. Blood flow is granular, intermittent, its velocity is slowed down.&#x0D; Conclusions. The severity of diabetic microangiopathy is directly proportional to the duration of the disease. The use of indicators of skin microcirculation makes it possible to predict the probability of the development of diabetic microangiopathy and the degree of its expressiveness in different periods of the disease.&#x0D;

Features of microcirculatory responses in experimental wound area in white rats

Objective: to examine changes in the microcirculatory bed parameters via laser Doppler flowmetry in the course of wound healing and the possibility of their use for upgrading the technology of evaluating the effectiveness of wound healing agents. Materials and Methods. The studies were performed on 25 white rats distributed between two groups: 10 control animals (intact rats) and 15 animals with a full-thickness experimental skin defect. The microcirculation parameters in the skin of experimental wound edges in rats were evaluated using laser Doppler flowmetry, and histological preparations of tissues in the wound area were analyzed. Results. Changes in skin microcirculation at the wound edges were characterized by inflammatory hyperemia manifested by an increase in the perfusion index by 27% and augmented normalized amplitudes of myogenic, respiratory and cardiogenic oscillations. Changes in microcirculation were verified by the morphological picture of inflammation, which reflects an increase in the number of vessels fully filled with arterial and venous blood, as well as in leukocyte infiltration of the wound edges and bottom. Conclusion. Monitoring of microcirculatory disorders occurring in the area of skin wounds allows assessing the dynamics of the reparative process, which could be used for developing and evaluating the effectiveness of existing medicamentous and non-medicamentous methods of stimulating regeneration.

Changes in Skin Microcirculation Resulting from Vibration Therapy in Women with Cellulite.

Background: Cellulite is a cosmetic defect that affects over 80% of post-pubertal women. One of its pathomechanisms involves microvascular dysfunction. It has been suggested that vibration is a physical stimulus that may improve circulation in the skin and muscles. The aim of this study was to evaluate the effect of local vibration on cutaneous microcirculation and on eliminating the symptoms of cellulite in women. Methods: A total of 57 healthy women with at least grade 1 cellulite were recruited and divided into four groups differing by treatment time (30′ or 60′) and position (sitting or lying) during the vibration treatments. Participants took part in 15 vibrotherapy sessions. Body composition, selected circumferences, cellulite grade, and thermographic images of buttocks and thighs were recorded. Results: Significant changes in skin temperature were observed in both studied areas after the first and last treatments in each group. A significant decrease in cellulite grade was observed after a series of treatments. The strongest effects were observed for the sitting position with a treatment time of 60 min. Conclusion: Vibration treatment improves microcirculation in cellulite-affected areas. Over time, no adaptation was observed, and subsequent treatments maintained the beneficial effects. Extending the treatment time increased its influence on the microcirculation in the skin.

Impaired Microvascular Function in Patients With Critical COVID-19.

OBJECTIVES:Severe coronavirus disease 2019 is characterized by infected microvascular endothelial cells. The primary aim of this study was to investigate microvascular function in patients with critical coronavirus disease 2019.DESIGN:A prospective observational study was conducted in which patients with critical and severe COVID-19 were investigated during acute disease phase and at least 3 months after disease onset.SETTING:Single-center study at Danderyd University Hospital.PATIENTS:Twenty-three patients with critical coronavirus disease 2019 treated with noninvasive or invasive mechanical ventilation, seven patients with severe COVID-19 with dyspnea or need of oxygen supply up to 8 L/min, and 15 noncoronavirus disease controls.INTERVENTIONS:None.MEASUREMENTS:Skin perfusion was investigated through laser speckle contrast imaging before and after iontophoresis of acetylcholine and sodium nitroprusside for determination of the endothelial-dependent and the endothelial-independent vasodilation, respectively.MAIN RESULTS:Patients with critical COVID-19 had higher basal skin perfusion during both the acute (34 ± 9 perfusion unit; p = 0.0003) and the postinfectious phase (29 ± 8 perfusion unit; p = 0.04), compared with noncoronavirus disease controls (23 ± 7 perfusion unit). In addition, endothelial-dependent and endothelial-independent vasodilation were reduced in patients with critical COVID-19 during the acute disease phase (p < 0.001 for both), whereas no significant differences between patients and controls were found during the postinfectious phase. In patients with severe COVID-19, basal skin perfusion and endothelial-dependent vasodilatation were not significantly changed, whereas endothelial-independent vasodilatation was reduced (p = 0.02) compared with controls.CONCLUSIONS:Changes in skin microcirculation in patients with critical COVID-19 indicate that the infection induces a systemic microvascular impairment with persisting long-term effects on the microvascular function.

MEASUREMENT OF SKIN DOSE AND RADIATION-INDUCED CHANGES IN SKIN MICROCIRCULATION IN CHRONIC TOTAL OCCLUSION PERCUTANEOUS CARDIAC INTERVENTIONS (CTO-PCI)

Skin injuries may occur when radiation doses to the skin exceed 2Gy. This study aimed to measure changes in skin microcirculation in patients undergoing chronic total occlusion percutaneous coronary interventions (CTO-PCI). In 14 patients, peak skin dose (PSD) was estimated with radiographic films and skin microcirculation was assessed with laser speckle contrast imaging (LSCI), before, 1 day after the intervention, and 4-6weeks later. The mean PSD was 1.8±0.9Gy. Peak skin microcirculation increased by 12% from 45±6 PU before to 50±9 PU 1 day after the intervention (p=0.01), and returned to 46±8 PU after 4-6weeks (p=0.15). There was no significant correlation between PSD and the change in perfusion, neither 1 day (r=-0.13, p=0.69) nor 4-6weeks after the intervention (r=0.33, p=0.35). These results suggest that there are no radiation-induced microvascular changes in the skin after CTO-PCI at skin doses below 2Gy.

Assessment of blood distribution in response to post-surgical steal syndrome: A novel technique based on Thermo-Anatomical Segmentation

The distal ischemic steal syndrome (ISS) is a complication following the construction of an arteriovenous (A-V) access for hemodialysis. The ability to non-invasively monitor changes in skin microcirculation improves both the diagnosis and treatment of vascular diseases. In this study, we propose a novel technique for evaluating the palms' blood distribution following arteriovenous access, based on thermal imaging. Furthermore, we utilize the thermal images to identify typical recovery patterns of patients that underwent this surgery and show that thermal images taken post-surgery reflect the patient's follow-up status. Thermal photographs were taken by a portable thermal camera from both hands before and after the A-V access surgery, and one month following the surgery, from ten dialysis patients. A novel term “Thermo-Anatomical Segmentation”, which enables a functional assessment of palm blood distribution was defined. Based on this segmentation it was shown that the greatest change after surgery was in the most distal region, the fingertips (p < 0.05). In addition, the changes in palm blood distribution in both hands were synchronized, which indicates a bilateral effect. An unsupervised machine learning model revealed two variables that determine the recovery pattern following the surgery: the palms' temperature difference pre- and post-surgery and the post-surgery difference between the treated and untreated hand. Our proposed framework provides a new technique for quantitative assessment of the palm's blood distribution. This technique may improve the clinical treatment of patients with vascular disease, particularly the patient-specific follow-up, in clinics as well as in homecare.

Changes in skin microcirculation in response to low-intensity electromagnetic radiation of the millimeter range

The tissue microhemodynamics plays a significant role in a tissue homeostasis. Any pathological processes were changes in functioning of microhemodynamics. This is causes is significant interesting to safe methods for its correction. One of such methods is exposure to low-intensity electromagnetic radiation of the millimeter (MM) range, which has pronounced of biological activity. The aim of the work was to identify changes in the processes of microcirculation in human skin when exposed to a low-intensity EMR MM range (wavelength - 7.1 mm; power flux density - 0.1 mW/cm2). The study was conducted on 40 volunteer girls aged 18-20 years. The exposure of low-intensity MM radiation was carried out daily for 10 days with an exposure of 30 minutes on the area of biologically active area GI-4. Microcirculation indices were recorded by laser Doppler flowmetry both in the area of influence of MM radiation (contact point of registration) and in the symmetrical effect of the area (distant point) to detect local and systemic changes in tissue blood flow under the action of this physical factor. The results of the study revealed for the first time that when exposed to low-intensity MM radiation, local changes in tissue blood flow in the contact point area were observed, manifested in changes in myogenic and endothelial oscillatory activity, starting from the first sessions of exposure, which indicates a decrease in peripheral resistance of precapillary sphincters and an increase in secretory activity of microvascular endothelium; changes in neurogenic oscillations-starting from the third session, which is accompanied by a decrease in arteriolar resistance; changes in pulse fluctuations - during the last tenth session of exposure, which is an indication of an increase in arteriolar blood filling. These changes were maintained during the entire period of exposure to this physical factor. Systemic changes in microcirculation parameters at a distant symmetrical point during the course action of MM radiation were characterized by changes in the neurogenic oscillator component, starting from the third session of exposure, and changes in the amplitude of endothelial and pulse oscillations - during the tenth session.

Objective assessment of skin microcirculation using a smartphone camera.

Existing techniques for assessment of microcirculation are limited by their large size and high costs and are often not so easy to use. Advances in mobile technology have enabled great improvements in smartphone sensor technology. In this study, we used SkinSight, an app for iPhone and iPad, to measure changes in skin microcirculation during physiological provocations. The system estimates changes in the concentration of hemoglobin in the skin by analyzing the reflected light emitted from the built-in light-emitting diode and detected by the camera of the smartphone. A relative hemoglobin (Hb) index was measured during a 5-min arterial occlusion, post-occlusive reactive hyperemia, and a 5-min venous occlusion in 10 healthy subjects, on two separate days. The index was calculated in an area of the skin from the color information in the images acquired by the phone camera. Polarized light spectroscopy imaging was used to measure changes in red blood cell concentration for comparison. During arterial occlusion, relative Hb index was unchanged compared to baseline (P = .40). After release of the cuff, a sudden 60%-75% increase in Hb index was observed (P < .001) followed by a gradual return to baseline. During venous occlusion, Hb index increased by 80% (P < .001) followed by a gradual decrease to baseline after reperfusion. Day-to-day reproducibility of the relative Hb index was excellent (ICC: 0.92, r = 0.94), although relative Hb index was consistently higher during the second day, possibly as a result of changed lighting conditions or calibration issues. Microvascular responses to physiological provocations in the skin can be accurately and reproducibly measured using a smartphone application. Although the system offers a handheld, easy to use and flexible technique for skin microvascular assessment, the effects of lighting on the measured values and need for calibration need to be further investigated.

New Approaches to Scaffold Biocompatibility Assessment

At the present day, the biocompatibility assessment of tissue engineering scaffolds and implants is an important issue in regenerative medicine. The present study aims to defining changes of skin microcirculation parameters in the area above scaffold implantation and using them as the criteria of dynamic estimation of biocompatibility. The experiment was performed and statistically approved with 45 white rats. The animals were exposed to subcutaneous scaffold implantation with both biocompatible and non-biocompatible scaffolds (polycaprolactone scaffolds and polycaprolactone scaffolds with adsorbed foreign protein respectively). Skin microcirculation changes in the above-scaffold area were estimated using Laser Doppler flowmetry. The investigation of morphological changes occurred after the implantation was also performed. It has been found that the dynamics of microcirculatory changes correlate with the intensity of the inflammatory reaction occurring in the tissues after scaffold implantation. These facts substantiate the use of tissue perfusion as the criteria of scaffold biocompatibility assessment in subcutaneous implantation tests. The potential and future prospects of non-invasive assessment of biocompatibility by Laser Doppler flowmetry for the optimization of scaffold biocompatibility assessment in subcutaneous implantation tests have received detailed explanation.

Skin microvascular circulation is not affected by diabetes duration in young patients with non-complicated type 1 diabetes mellitus.

Skin microcirculation is recognized as an appropriate model to use when investigating the relationship between cardiovascular risk factors and microvascular function. It is currently amatter of debate whether studies on skin microcirculation in young type 1 diabetic patients without existing microangiopathy may be helpful in identifying subjects with impaired endothelial function. To evaluate the potential changes in skin microcirculation of patients up age of 18 years using capillaroscopy, post reactive hyperaemia (PORH) and venous occlusion (VO) tests, and to establish the relationship between those changes and disease duration and metabolic control in patients with type 1 diabetes. Study group consisted of 112 pediatric patients aged 8.4-18.0 years, with amedian age of 14.95 years. The median diabetes duration and age at onset were 5 years and 9.6 years, respectively. The median HbA1c in the studied group was 7.6% at the time when the microcirculation was being examined. Capillaroscopy studies were focused on type 1 diabetic patients and employed non-selective stimuli such as the PORH and VO tests. The relative area covered by capillaries (coverage) was measured before the testing and again after the PORH and VO tests. The analysis revealed that none of the skin microcirculation indices correlated significantly with patient age, diabetes duration or metabolic control. In young patients with uncomplicated type 1 diabetes mellitus skin microcirculation function is not dependent on age, disease duration or metabolic control.

Brief Exposure of Skin to Near-Infrared Laser Modulates Mast Cell Function and Augments the Immune Response.

The treatment of skin with a low-power continuous-wave (CW) near-infrared (NIR) laser prior to vaccination is an emerging strategy to augment the immune response to intradermal vaccine, potentially substituting for chemical adjuvant, which has been linked to adverse effects of vaccines. This approach proved to be low cost, simple, small, and readily translatable compared with the previously explored pulsed-wave medical lasers. However, little is known on the mode of laser-tissue interaction eliciting the adjuvant effect. In this study, we sought to identify the pathways leading to the immunological events by examining the alteration of responses resulting from genetic ablation of innate subsets including mast cells and specific dendritic cell populations in an established model of intradermal vaccination and analyzing functional changes of skin microcirculation upon the CW NIR laser treatment in mice. We found that a CW NIR laser transiently stimulates mast cells via generation of reactive oxygen species, establishes an immunostimulatory milieu in the exposed tissue, and provides migration cues for dermal CD103+ dendritic cells without inducing prolonged inflammation, ultimately augmenting the adaptive immune response. These results indicate that use of an NIR laser with distinct wavelength and power is a safe and effective tool to reproducibly modulate innate programs in skin. These mechanistic findings would accelerate the clinical translation of this technology and warrant further explorations into the broader application of NIR lasers to the treatment of immune-related skin diseases.

EP-1154: Changes in skin microcirculation during radiation therapy for breast cancer

EP-1154: Changes in skin microcirculation during radiation therapy for breast cancer

Changes in skin microcirculation during radiation therapy for breast cancer

Background: The majority of breast cancer patients who receive radiation treatment are affected by acute radiation-induced skin changes. The assessment of these changes is usually done by subjective methods, which complicates the comparison between different treatments or patient groups. This study investigates the feasibility of new robust methods for monitoring skin microcirculation to objectively assess and quantify acute skin reactions during radiation treatment.Material and methods: Laser Doppler flowmetry, laser speckle contrast imaging, and polarized light spectroscopy imaging were used to measure radiation-induced changes in microvascular perfusion and red blood cell concentration (RBC) in the skin of 15 patients undergoing adjuvant radiation therapy for breast cancer. Measurements were made before treatment, once a week during treatment, and directly after the last fraction.Results: In the treated breast, perfusion and RBC concentration were increased after 1–5 fractions (2.66–13.3 Gy) compared to baseline. The largest effects were seen in the areola and the medial area. No changes in perfusion and RBC concentration were seen in the untreated breast. In contrast, Radiation Therapy Oncology Group (RTOG) scores were increased only after 2 weeks of treatment, which demonstrates the potential of the proposed methods for early assessment of skin changes. Also, there was a moderate to good correlation between the perfusion (r = 0.52) and RBC concentration (r = 0.59) and the RTOG score given a week later.Conclusion: We conclude that radiation-induced microvascular changes in the skin can be objectively measured using novel camera-based techniques before visual changes in the skin are apparent. Objective measurement of microvascular changes in the skin may be valuable in the comparison of skin reactions between different radiation treatments and possibly in predicting acute skin effects at an earlier stage.

Hyperspectral Imaging as an Early Biomarker for Radiation Exposure and Microcirculatory Damage.

Radiation exposure can lead to detrimental effects in skin microcirculation. The precise relationship between radiation dose received and its effect on cutaneous perfusion still remains controversial. Previously, we have shown that hyperspectral imaging (HSI) is able to demonstrate long-term reductions in cutaneous perfusion secondary to chronic microvascular injury. This study characterizes the changes in skin microcirculation in response to varying doses of ionizing radiation and investigates these microcirculatory changes as a possible early non-invasive biomarker that may correlate with the extent of long-term microvascular damage. Immunocompetent hairless mice (n = 66) were exposed to single fractions of superficial beta-irradiation in doses of 0, 5, 10, 20, 35, or 50 Gy. A HSI device was utilized to measure deoxygenated hemoglobin levels in irradiated and control areas. HSI measurements were performed at baseline before radiation exposure and for the first 3 days post-irradiation. Maximum macroscopic skin reactions were graded, and histological assessment of cutaneous microvascular densities at 4 weeks post-irradiation was performed in harvested tissue by CD31 immunohistochemistry. CD31 immunohistochemistry demonstrated a significant correlation (r = 0.90, p < 0.0001) between dose and vessel density reduction at 4 weeks. Using HSI analysis, early changes in deoxygenated hemoglobin levels were observed during the first 3 days post-irradiation in all groups. These deoxygenated hemoglobin changes varied proportionally with dose (r = 0.98, p < 0.0001) and skin reactions (r = 0.98, p < 0.0001). There was a highly significant correlation (r = 0.91, p < 0.0001) between these early changes in deoxygenated hemoglobin and late vascular injury severity assessed at the end of 4 weeks. Radiation dose is directly correlated with cutaneous microvascular injury severity at 4 weeks in our model. Early post-exposure measurement of cutaneous deoxygenated hemoglobin levels may be a useful biomarker for radiation dose reconstruction and predictor for chronic microvascular injury.

Microcirculation in patients with arterial hypertension, coronary heart disease and cognitive impairment on treatment with Actovegin

Aim. To investigate the effect of antihypertensive and neurometabolic treatment on the microcirculation in patients with arterial hypertension, coronary heart disease and cognitive impairment. Materials and methods. In total 60 patients with arterial hypertension (AH) of 2-3 stage, coronary heart disease (extertional angina I-II functional class) and mild cognitive impairment were randomized into two groups. In first group, patients were administered antihypertensive medication and course of Actovegin (Actovegin group) while in second group patients received only antihypertensive treatment (control group). Assesment of skin microcirculation by performing of capillaroscopy and laser Doppler flowmetry and assessment of cognitive function (Shulte table) were provided three times: 1 - before antihypertensive treatment correction, 2 - at reaching of target blood pressure (BP), 3 in 4-5 weeks after. Results. Adjustment of therapy led to appropriate blood pressure control in both groups without significant differences between them. Patients in Actovegin group had significant cognitive improvement (p<0.001), significant increase in amount of functioning capillaries (p<0.05), decrease in the degree of hydration of interstitial space (p<0.05) and reduced time of reactive postocclusive hyperemia (p<0.05) at the second and third timepoint. There was no positive changes in skin microcirculation nor cognitive functions in control group. Conclusion. Reaching of target BP did not result in cognitive improvement. Concomitant use of Actovegin and antihypertensive treatment did not influence BP level but led to the reducing of functional rarefication and latent water retention in tissues as well as to cognitive impairment.

Peripheral microcirculatory hemodynamic changes in patients with myocardial ischemia.

Patients with coronary heart disease demonstrate changes in skin microcirculation and a decrease in cutaneous blood mass. The goal of this study was to assess the feasibility of diagnosing myocardial ischemia based on peripheral microcirculatory variables. The skin microcirculatory measurements were monitored using an LPT system comprising a Laser Doppler Flowmeter (LDF), a photoplethysmograph (PPG) and a transcutaneous oxygen tension device (tc-PO2). Concurrently, heart rate and blood pressure were monitored. Measurements were performed before and after exercise stress test. Subjects were divided into ischemic (20) and nonischemic (27) patients based on myocardial perfusion imaging (MPI). The results indicate differences in LPT variables between ischemic and nonischemic patients following exercise, while no differences in the central variable values were observed between the two groups. Peripheral microcirculatory variables may be useful for non-invasive assessment of myocardial ischemia. The system has clinical potential for sensitive and noninvasive monitoring of vital variables during medical procedures in clinics, as well as in home care for patients who suffer from ischemic cardiac diseases.

Vasculopathy, inflammation, and blood flow in leg ulcers of patients with sickle cell anemia

Chronic leg ulcers are frequent and debilitating complications of sickle cell anemia. Inadequate blood supply has been postulated to be an important factor in their occurrence and delayed healing. Little is known about their microcirculatory and histopathological changes. We evaluated the microcirculation of lower extremity ulcers with laser speckle contrast imaging and infrared thermography and obtained clinical and laboratory characteristics in 18 adults with sickle cell anemia and chronic leg ulcers. Skin biopsies were obtained in four subjects. Subjects had markers of severe disease, anemia, high degree of hemolysis, inflammation, and thrombophilia. The highest blood flow was present in the ulcer bed, progressively less in the immediate periwound area, and an unaffected control skin area in the same extremity. Microscopic examination showed evidence of venostasis, inflammation, and vasculopathy. Blood vessels were increased in number, had activated endothelium and evidence of thrombosis/recanalization. High blood flow may be due to chronic inflammation, cutaneous vasodilatation, venostasis, and in situ thrombosis. These changes in skin microcirculation are similar to chronic venous ulcers in the non-sickle cell disease (SCD) population, thus suggesting that leg ulcers may be another end-organ complication with endothelial dysfunction that appears in patients with SCD at a younger age and with higher frequency than in the general population.

Effects of some anesthetic agents on skin microcirculation evaluated by laser Doppler perfusion imaging in mice

BackgroundAnesthetic agents alter microcirculation, influencing tissue oxygenation and delivery of vital substrates. Laser Doppler perfusion imaging is a widespread technique in the field of microvascular research that can evaluate noninvasively and in real time the effects of environmental conditions, physical manipulations, diseases and treatments on peripheral perfusion. This study aims to evaluate laser Doppler perfusion imaging as a means to detect changes in skin microcirculation induced by some popular anesthetic agents in a murine model. Twenty-four age- and gender-matched healthy CD1 mice were examined by laser Doppler perfusion imaging. The skin microcirculatory response was measured at the level of plantar surfaces during isoflurane anesthesia with or without subsequent dexmedetomidine or acepromazine. At the end of the procedure, dexmedetomidine was reversed by atipamezole administration.ResultsIn all mice, skin blood flow under isoflurane anesthesia did not show significant differences over time (P = 0.1). The serial perfusion pattern and values following acepromazine or dexmedetomidine administration differed significantly (P < 0.05).ConclusionsWe standardized a reliable laser Doppler perfusion imaging protocol to non-invasively assess changes in skin microcirculation induced by anesthesia in mice, considering the advantages and drawbacks of this technique and its translational value.