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Objectives: The aim of this study was to evaluate the peri-implant perfusion, such as oxygen saturation, the relative amount of hemoglobin, and blood flow, in implants placed in pristine bone and avascular and microvascular grafts using a non-invasive measurement method. Materials and methods: A total of 58 patients with 241 implants were included. Among them, 106 implants were based in native bone (group I), 75 implants were inserted into avascular bone grafts (group II), and 60 implants were placed in microvascular bone grafts (group III). Gingival perfusion was measured using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS). Implants with signs of gingival inflammation were excluded to analyze healthy implant perfusion in different bony envelopes. Results: The mean values for oxygen saturation, relative hemoglobin levels, and blood flow did not differ significantly between the groups (p = 0.404, p = 0.081, and p = 0.291, respectively). There was no significant difference in perfusion between implants that were surrounded by mucosa and implants based within cutaneous transplants (p = 0.456; p = 0.628, and p = 0.091, respectively). Conclusion: No differences in perfusion were found between implants inserted into native bone and implants involving bone or soft tissue augmentation. However, implants based in avascular and microvascular transplants showed higher rates of peri-implant inflammation. Clinical relevance: Peri-implant perfusion seems to be comparable for all implants after they heal, irrespective of their bony surroundings. Although perfusion does not differ significantly, other factors may make implants in avascular and microvascular transplants vulnerable to peri-implant inflammation. [ABSTRACT FROM AUTHOR]

Wavelet analysis (WA) provides superior time-frequency decomposition of complex signals than conventional spectral analysis tools. To illustrate its usefulness in assessing transient phenomena, we applied a custom-developed WA algorithm to laser-Doppler (LD) signals of the cutaneous microcirculation measured at glabrous (finger pulp) and nonglabrous (forearm) sites during early recovery after dynamic exercise. This phase, importantly contributing to the establishment of thermal homeostasis after exercise cessation, has not been adequately explored because of its complex, transient form. Using WA, we decomposed the LD signals measured during the baseline and early recovery into power spectra of characteristic frequency intervals corresponding to endothelial nitric oxide (NO)-dependent, neurogenic, myogenic, respiratory, and cardiac physiological influence. Assessment of relative power (RP), defined as the ratio between the median power in the frequency interval and the median power of the total spectrum, revealed that endothelial NO-dependent (5.87 early recovery; 1.53 baseline; P = 0.005; Wilcoxon signed-rank test) and respiratory (0.71 early recovery; 0.40 baseline; P = 0.001) components were significantly increased, and myogenic component (1.35 early recovery; 1.83 baseline; P = 0.02) significantly decreased during early recovery in the finger pulp. In the forearm, only the RP of the endothelial NO-dependent (1.90 early recovery; 0.94 baseline; P = 0.009) component was significantly increased. WA presents an irreplaceable tool for the assessment of transient phenomena. The relative contribution of the physiological mechanisms controlling the microcirculatory response in the early recovery phase appears to differ in glabrous and nonglabrous skin when compared with baseline; moreover, the endothelial NO-dependent influence seems to play an important role. [ABSTRACT FROM AUTHOR]

Abstract Background The aim of this study was to determine the values of different perfusion parameters- such as oxygen saturation, the relative amount of hemoglobin, and blood flow- in healthy subjects compared to patients with gingivitis as a non-invasive measurement method. Methods A total of 114 subjects were enrolled in this study and separated into subjects with gingivitis (50) and without gingivitis (64) based on clinical examination. Gingival perfusion was measured at 22 points in the maxilla and mandible using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS) with the “oxygen to see” device. All patients underwent measurement of gingival perfusion, followed by the clinical evaluation (measurement of probing depths, evaluation of bleeding on probing, plaque level, and biotype). Perfusion parameters were compared between the groups, associations between the non-invasive and clinical measurements were analyzed, and theoretical optimal cut-off values for predicting gingivitis were calculated with receiver operating characteristics. Results The mean oxygen saturation, mean relative amount of hemoglobin, and mean blood flow all significantly differed between the groups with and without gingivitis (p = 0.005, p 40 AU (p

Introduction: Changes in the microcirculation (MC) system reflect abnormalities of physiological processes in the body and serve as a diagnostic and prognostic factor in a number of pathological conditions, including inflammatory lesions of periodontal tissues. Since in the pathogenesis of microcirculatory disorders an important role is played by the processes of free-radical oxidation, medications with antioxidant effects are of certain interest in terms of pharmacological correction of blood flow disorders in the periodontal complex. It was of interest to conduct a comparative assessment of the effects of Soderm®-Forte, Cytoflavin® and their combination on MC in the gingival mucosa in rats. The aim of the study was to identify whether Soderm®-Forte, Cytoflavin® and their combination can improve microcirculation in the gingival mucosa in rats. Materials and Methods: The study of MC in the gingival mucosa in rats was carried out by using the laser Doppler Flowmetry method. Four groups of rats with 10 animals in each were formed: Group 1 – control; Groups 2-4 – experimental groups, in which Soderm®-Forte gel was applied to the gingival mucosa of the lower incisors, Cytoflavin®(100 mg/kg intraperitoneally – i.p.) was injected, and gel Soderm®-Forte was applied to the gingival mucosa against the background of injecting Cytoflavin®, respectively. The indicators of blood flow were recorded 30 and 60 minutes later. Results and Discussion: Soderm®-Fote improved MC in the gingival mucosa by increasing the basal level of NO, the activity of precapillary sphincters and metarteriolas and decreasing the activity of adrenergic vasomotors. Cytoflavin®increased the activity of precapillary sphincters and metarteriolas, the extravascular components of MC, without changing perfusion of the gingival mucosa. The combination of Soderm®-Forte and Cytoflavin® improved MC to a lesser extent than only Soderm®-Forte, but to a bigger extend than Cytoflavin®. Conclusion: According to the capacity to increase blood flow in the gingival mucosa in rats, the tested substances and their combination can be arranged in the following way: Soderm®-Forte > Soderm®-Forte+Cytoflavin® > Cytoflavin®.

Background: The aim of this study was to determine the values of different perfusion parameters- such as oxygen saturation, the relative amount of hemoglobin, and blood flow- in healthy subjects compared to patients with gingivitis as a non-invasive measurement method. Methods: A total of 114 subjects were enrolled in this study and separated into subjects with gingivitis (50) and without gingivitis (64) based on clinical examination. Gingival perfusion was measured at 22 points in the maxilla and mandible using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS) with the "oxygen to see" device. All patients underwent measurement of gingival perfusion, followed by the clinical evaluation (measurement of probing depths, evaluation of bleeding on probing, plaque level, and biotype). Perfusion parameters were compared between the groups, associations between the non-invasive and clinical measurements were analyzed, and theoretical optimal cut-off values for predicting gingivitis were calculated with receiver operating characteristics. Results: The mean oxygen saturation, mean relative amount of hemoglobin, and mean blood flow all significantly differed between the groups with and without gingivitis (p = 0.005, p < 0.001, and p < 0.001, respectively). The cut-off value for predicting gingivitis was > 40 AU (p < 0.001; sensitivity 0.90, specificity 0.67). Conclusions: As a non-invasive method, LDF-TS can help determine gingival hyperemia. Flow values above 40 AU indicate a higher risk of hyperemia, which can be associated with inflammation. The LDF-TS method can be used for the objective evaluation of perfusion parameters during routine examinations and can signal the progression of hyperperfusion before any change in clinical parameters is observed. Trial registration: All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved by the institutional Clinical Research Ethics Committee (Ethik-Kommission der Medizinischen Fakultät der RWTH Aachen, Decision Number 286/20) and retrospectively registered by the German Clinical Trials Register (File Number DRKS00024048, registered on the 15th of October 2021). [ABSTRACT FROM AUTHOR]

Introduction: Changes in the microcirculation (MC) system reflect abnormalities of physiological processes in the body and serve as a diagnostic and prognostic factor in a number of pathological conditions, including inflammatory lesions of periodontal tissues. Since in the pathogenesis of microcirculatory disorders an important role is played by the processes of free-radical oxidation, medications with antioxidant effects are of certain interest in terms of pharmacological correction of blood flow disorders in the periodontal complex. It was of interest to conduct a comparative assessment of the effects of Soderm®-Forte, Cytoflavin® and their combination on MC in the gingival mucosa in rats. The aim of the study was to identify whether Soderm®-Forte, Cytoflavin® and their combination can improve microcirculation in the gingival mucosa in rats. Materials and Methods: The study of MC in the gingival mucosa in rats was carried out by using the laser Doppler Flowmetry method. Four groups of rats with 10 animals in each were formed: Group 1 - control; Groups 2-4 - experimental groups, in which Soderm®-Forte gel was applied to the gingival mucosa of the lower incisors, Cytoflavin® (100 mg/kg intraperitoneally - i.p.) was injected, and gel Soderm®-Forte was applied to the gingival mucosa against the background of injecting Cytoflavin®, respectively. The indicators of blood flow were recorded 30 and 60 minutes later. Results and Discussion: Soderm®-Fote improved MC in the gingival mucosa by increasing the basal level of NO, the activity of precapillary sphincters and metarteriolas and decreasing the activity of adrenergic vasomotors. Cytoflavin® increased the activity of precapillary sphincters and metarteriolas, the extravascular components of MC, without changing perfusion of the gingival mucosa. The combination of Soderm®-Forte and Cytoflavin® improved MC to a lesser extent than only Soderm®-Forte, but to a bigger extend than Cytoflavin®. Conclusion: According to the capacity to increase blood flow in the gingival mucosa in rats, the tested substances and their combination can be arranged in the following way: Soderm®-Forte > Soderm®-Forte+Cytoflavin® > Cytoflavin®. [ABSTRACT FROM AUTHOR]

Abstract Background Previous studies of pulpal blood flow (PBF) changes in anterior teeth have been limited in the early phase of orthodontic treatment; less is known about the blood supply of anterior teeth in bimaxillary protrusion patients after orthodontic retraction. Methods Fifty bimaxillary protrusion patients (25 orthodontic patients ready for debonding and 25 non-orthodontic patients) were selected as study participants. The PBF of maxillary and mandibular anterior teeth were measured using laser Doppler flowmetry. For orthodontic patients, the PBF was measured at 1 day (T1), 1 month (T2), and 3 months (T3) after fixed appliance removal. Non-orthodontic patient PBF was measured as a control. Cone-beam computed tomography (CBCT) examinations before and after orthodontic treatment were performed for orthodontic patients to measure the root resorption. The anterior teeth in orthodontic group were further divided into subgroups according to root resorption and patient age. Results At T1 and T3, PBF changes did not differ significantly between the orthodontic and non-orthodontic groups. Maxillary lateral incisor, maxillary central incisor, and mandibular lateral incisor PBFs at T2 were significantly higher in the orthodontic group (P = 0.048, P = 0.04, and P = 0.021). No significant difference in PBF was found between the root resorption and non-resorption subgroups at any time point. Adolescent patients showed a higher PBF in the maxillary lateral incisor at T2 (12.23 ± 3.48) relative to that at T1 (9.10 ± 3.76) and T3 (9.81 ± 2.80) with statistically significant difference (P = 0.020). Conclusion For bimaxillary protrusion patients with four premolars extraction, PBF in the maxillary anterior teeth increased transiently after orthodontic appliance removal and then returned to non-orthodontic levels 3 months later. This effect was more pronounced in adolescents. The PBF of anterior teeth after orthodontic retraction may not be influenced by root resorption.

Since of its introduction in 1980s, laser speckle imaging has become a powerful tool in flow imaging. Its high performance and low cost made it one of the preferable imaging methods. Initially, speckle contrast measurements were the main algorithm for analyzing laser speckle images in biological flows. Speckle contrast measurements, also referred as Laser Speckle Contrast Imaging (LSCI), use statistical properties of speckle patterns to create mapped image of the blood vessels. In this communication, a new method named Laser Speckle Optical Flow Imaging (LSOFI) is introduced. This method uses the optical flow algorithms to calculate the apparent motion of laser speckle patterns. The differences in the apparent motion of speckle patterns are used to identify the blood vessels from surrounding tissue. LSOFI has better spatial and temporal resolution compared to LSCI. This higher spatial resolution enables LSOFI to be used for autonomous blood vessels detection. Furthermore, Graphics Processing Unit (GPU) based LSOFI can be used for quasi real time imaging.

While clinical examination is needed for burn severity diagnosis, several emerging technologies aim to quantify this process for added objectivity. Accurate assessments become easier after burn progression, but earlier assessments of partial thickness burn depth could lead to earlier excision and grafting and subsequent improved healing times, reduced rates of scarring/infection, and shorter hospital stays. Spatial Frequency Domain Imaging (SFDI), Laser Speckle Imaging (LSI) and thermal imaging are three non-invasive imaging modalities that have some diagnostic ability for noninvasive assessment of burn severity, but have not been compared in a controlled experiment. Here we tested the ability of these imaging techniques to assess the severity of histologically confirmed graded burns in a swine model. Controlled, graded burn wounds, 3cm in diameter were created on the dorsum of Yorkshire pigs (n=3, 45-55kg) using a custom-made burn tool that ensures consistent pressure has been employed by various burn research groups. For each pig, a total of 16 burn wounds were created on the dorsal side. Biopsies were taken for histological analysis to verify the severity of the burn. Clinical analysis, SFDI, LSI and thermal imaging were performed at 24 and 72h after burn to assess the accuracy of each imaging technique. In terms of diagnostic accuracy, using histology as a reference, SFDI (85%) and clinical analysis (83%) performed significantly better that LSI (75%) and thermography (73%) 24h after the burn. There was no statistically significant improvement from 24 to 72h across the different imaging modalities. These data indicate that these imaging modalities, and specifically SFDI, can be added to the burn clinicians' toolbox to aid in early assessment of burn severity.

Major complications of diabetes lead to inflammation and oxidative stress, delayed wound healing, and persistent ulcers. The high morbidity, mortality rate, and associated costs of management suggest a need for non-invasive methods that will enable the early detection of at-risk tissue. We have compared the wound-healing process that occurs in streptozotocin (STZ)-treated diabetic rats with non-diabetic controls using contrast changes in colour photography (ie, Weber Contrast) and the non-invasive optical method Spatial Frequency Domain Imaging (SFDI). This technology can be used to quantify the structural and metabolic properties of in-vivo tissue by measuring oxyhaemoglobin concentration (HbO2 ), deoxyhaemoglobin concentration (Hb), and oxygen saturation (StO2 ) within the visible boundaries of each wound. We also evaluated the changes in inducible nitric oxide synthase (iNOS) in the dermis using immunohistochemistry. Contrast changes in colour photographs showed that diabetic rats healed at a slower rate in comparison with non-diabetic control, with the most significant change occurring at 7 days after the punch biopsy. We observed lower HbO2 , StO2 , and elevated Hb concentrations in the diabetic wounds. The iNOS level was higher in the dermis of the diabetic rats compared with the non-diabetic rats. Our results showed that, in diabetes, there is higher level of iNOS that can lead to an observed reduction in HbO2 levels. iNOS is linked to increased inflammation, leading to prolonged wound healing. Our results suggest that SFDI has potential as a non-invasive assessment of markers of wound-healing impairment.

Traditional Thai massage is one of the alternative treatments for diabetic feet. However, the specific amount of pressing pressure applied to the foot during Thai foot massage is unknown. This study aimed to evaluate the effect of light pressing pressure on foot skin blood flow in type 2 diabetic patients. A single-arm repeated measures was conducted. Forty-three participants were recruited via the subjective examination and screening using the Michigan Neuropathy Screening Instrument. To obtain foot skin blood flow by laser doppler blood flowmetry, a probe was pasted on the 1st distal phalange of the big toe. Light pressure at a single point was applied on the plantar skin fold between the bases of the second and third toes by using the digital algometer. The pressure was applied gently, then increased slightly until the participant started to feel some minor discomfort. Patients were asked to rate their pain intensity using the visual analogue scale. The average pressing pressure without discomfort was 3.55 ± 1.04 kg/cm2. The foot skin blood flow increased significantly immediately after the pressing pressure, and this increase represented about 1.9 times when compared with the baseline (p < 0.001). The application of light pressing pressure could be used as a basic standard criterion for massage to improve the foot skin blood flow in type 2 diabetic patients. • The pressing pressure providing some minor discomfort on DM foot could be a safety performance for Traditional Thai massage. • The light-discomfort pressing pressure improved 2 times of the foot skin blood flow in diabetic foot. patients. [ABSTRACT FROM AUTHOR]

Abstract SARS‐CoV‐2 is causing devastation both in human lives and economic resources. When the world seems to start overcoming the pandemics scourge, the threat of long‐term complications of COVID‐19 is rising. Reports show that some of these long‐term effects may contribute to the main cause of morbimortality worldwide: the vascular diseases. Given the evidence of damage in the endothelial cells due to SARS‐CoV‐2 and that endothelial dysfunction precedes the development of arteriosclerosis, the authors propose to measure endothelial function around 6–12 months after acute disease in hypertensive patients, especially if they have other cardiovascular risk factors or overt vascular disease. The methods the authors propose are cost‐effective and can be made available to any hypertension unit. These methods could be the “in vivo” assessment of endothelial function by flow mediated vasodilatation after ischemia by Laser‐Doppler flowmetry and the measurement of plasma free circulating DNA and microparticles of endothelial origin.

Background: Previous studies of pulpal blood flow (PBF) changes in anterior teeth have been limited in the early phase of orthodontic treatment; less is known about the blood supply of anterior teeth in bimaxillary protrusion patients after orthodontic retraction. Methods: Fifty bimaxillary protrusion patients (25 orthodontic patients ready for debonding and 25 non-orthodontic patients) were selected as study participants. The PBF of maxillary and mandibular anterior teeth were measured using laser Doppler flowmetry. For orthodontic patients, the PBF was measured at 1 day (T1), 1 month (T2), and 3 months (T3) after fixed appliance removal. Non-orthodontic patient PBF was measured as a control. Cone-beam computed tomography (CBCT) examinations before and after orthodontic treatment were performed for orthodontic patients to measure the root resorption. The anterior teeth in orthodontic group were further divided into subgroups according to root resorption and patient age. Results: At T1 and T3, PBF changes did not differ significantly between the orthodontic and non-orthodontic groups. Maxillary lateral incisor, maxillary central incisor, and mandibular lateral incisor PBFs at T2 were significantly higher in the orthodontic group (P = 0.048, P = 0.04, and P = 0.021). No significant difference in PBF was found between the root resorption and non-resorption subgroups at any time point. Adolescent patients showed a higher PBF in the maxillary lateral incisor at T2 (12.23 ± 3.48) relative to that at T1 (9.10 ± 3.76) and T3 (9.81 ± 2.80) with statistically significant difference (P = 0.020). Conclusion: For bimaxillary protrusion patients with four premolars extraction, PBF in the maxillary anterior teeth increased transiently after orthodontic appliance removal and then returned to non-orthodontic levels 3 months later. This effect was more pronounced in adolescents. The PBF of anterior teeth after orthodontic retraction may not be influenced by root resorption. [ABSTRACT FROM AUTHOR]

Retinal vascular resistance is of interest in glaucoma research, as a potential link between retinal ganglion cell loss and observed phenomena including disrupted vascular autoregulation, altered biomechanical stiffness, and impaired neurovascular coupling. It can now be assessed in vivo, using laser speckle flowgraphy. However, continued progress in the field requires better understanding of its physiology. In this study, we test the hypothesis of homogeneity of vascular resistance indices between regions of the retina: specifically, between superior and inferior hemifields. The resistivity index (maximum flow minus minimum flow, as a proportion of the maximum) and pulsatility index (maximum minus minimum, as a proportion of the mean) were measured in major vessels within the optic nerve head, in the remaining tissue within the optic nerve head, and in peripapillary branch retinal arteries, separated in each case into superior and inferior quadrants. This was performed in 378 eyes of 189 participants with suspected, early or moderate glaucoma; and in 99 eyes of 50 participants without any ocular pathology. In the glaucoma cohort, the resistivity index was on average 9% higher superiorly than inferiorly in vessels within the optic nerve head; 8% higher superiorly in remaining tissue; and 8% higher superiorly in peripapillary vessels (all p < 0.001). The pulsatility index was on average 11% higher superiorly in all three locations (all p < 0.001). Average flow was slightly higher superiorly in major vessels in the nerve head, but higher inferiorly elsewhere. In the healthy control cohort, resistivity index was higher superiorly by 10% in vessels and 8% in tissue within the optic nerve head; pulsatility index was 12% and 10% higher superiorly respectively (all p < 0.001). The fact that these differences were similar between the two cohorts suggests that they are not caused by the disease process. However, it is notable that glaucomatous loss most frequently occurs first in the superior visual field, corresponding with the inferior retina. The finding that vascular resistance indices are consistently higher in the superior retina warrants further investigation, both for its causes and consequences., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective : It has been stated that blood pigments within discolored teeth may interfere with Laser Doppler Flowmetry (LDF) measurements. The aim of this study was to assess pulp vitality with LDF in a cohort of discolored traumatized teeth referred for endodontic treatment or where the referring dentist had doubts regarding maintained tooth vitality. Background: Discoloration of teeth is a common sequel of dental trauma. Still today, it is taken as an indicator for root canal treatment. Transient apical breakdown (TAB) is confused with apical periodontitis, although it is a sequel of dental trauma in young mature teeth and will result in revascularization and dissolution of the apical radiolucency. Methods: A total of 26 patients with 28 discolored teeth, belonging to a cohort of referred patients with traumatized teeth referred for root canal treatment and/or pulp vitality assessment were screened on color with photographs by three investigators, with traditional sensibility tests and with a Moor VMS II LDF meter. Results: The color of the intrinsically discolored teeth was grayish in 58% of teeth, blue 20%, pink/crimson 12%, and yellow 4%. Eighty-five percent were central maxillary incisors, 11% were mandibulary incisors. Thanks to LDF, 43% of the trauma cases in this small cohort with discoloration underwent root canal treatment instead of 70% with traditional sensibility tests as indicator. TAB was found in 11%. Conclusions: LDF was decisive in diagnosing vitality of discolored teeth and there was no negative impact of tooth discoloration on LDF measurements.

Selective distribution of cerebral blood flow (CBF) to vital brain regions likely occurs during rapid severe hypotension caused by tachyarrhythmia, but has not yet been demonstrated. In this study, we aimed to test the hypothesis that CBF is differentially preserved between brain regions depending on the degree of hypotension. In anesthetized rats, CBF was measured in the motor cortex (MC), medial prefrontal cortex, amygdala, thalamus, dorsal hypothalamus, hippocampus, ventral tegmental area, dorsolateral periaqueductal gray (dlPAG), and parabrachial nucleus (PB) by using laser-Doppler flowmetry. Ventricular pacing was performed for 30 s at 550-800 beats/min. The cerebrovascular CO 2 response time and reactivity were evaluated during 5% CO 2 exposure. During 1-4 s of ventricular pacing, mean arterial pressure (MAP) rapidly decreased, with minor changes in central venous and intracranial pressures. CBF was relatively well maintained in brain regions other than the MC ( Ps ≤ 0.012) when moderate hypotension occurred (-34 mmHg ≤ ΔMAP ≤ -15 mmHg), whereas severe hypotension (-54 mmHg ≤ ΔMAP ≤ -35 mmHg) induced selective CBF distribution to regions other than the MC, thalamus, and dlPAG. The cerebrovascular CO 2 response time/reactivity was rapid or high in the thalamus, dlPAG, and PB, which almost completely differed from the brain regions in which CBF was relatively maintained during pacing-induced severe hypotension. These results suggest that regional heterogeneity of CBF arises depending on the degree of tachyarrhythmia-induced hypotension. Clarifying the mechanisms and functions of CBF maintenance would be beneficial to syncope and cerebral ischemia management in patients with arrhythmia.

Objective: Diabetes can lead to microvascular complications such as diabetic neuropathy, nephropathy, and retinopathy. Hyperglycemia may initiate microvascular function impairment early in the course of diabetes, even prior to its clinical establishment during the pre-diabetes stage. Microvascular vasomotion, that is, the rhythmic arteriolar constriction and dilation, is an important function that regulates oxygen and nutrient delivery within the tissue and regulates peripheral resistance. Using laser Doppler flowmetry (LDF), vasomotion in skin microcirculation can be measured as flowmotion. Changes in flowmotion have been shown in individuals with obesity, and type 1 or type 2 diabetes mellitus. However, no data are available on associations between hyperglycemia and flowmotion in the general population. Our aim was to study whether measures of hyperglycemia were associated with different components of skin microvascular flowmotion (SMF) in a population-based cohort (The Maastricht Study)., Methods: Data from 7293 participants of The Maastricht Study were used. SMF was measured using LDF. Endothelial, neurogenic and myogenic component SMF power were used as dependent variables. We investigated the associations of glucose metabolism status (normal glucose metabolism, prediabetes, and type 2 diabetes mellitus), measures of hyperglycemia (fasting plasma glucose [FPG], 2-h post-load glucose [2 h-PG], HbA1c, advanced glycation end-products [AGEs] assessed as skin autofluorescence [SAF]), and indices of glucose variability (incremental glucose peak [IGP] and continuous glucose monitoring [CGM] -assessed as standard deviation [SD]) with each component of SMF power. We used linear regression analyses with adjustments for confounders, and trend analyses., Results: We observed consistent negative associations between HbA1c levels and all three (endothelial, neurogenic, and myogenic) skin microvascular flowmotion (SMF) powers in the additionally adjusted model. Similarly, in the conservative model, we found that multiple hyperglycemia metrics such as GMS trend, PreD, T2DM, FPG, 2 h-PG, and HbA1c were consistently negatively associated with all three SMF powers., Conclusions: We showed that skin microvascular flowmotion is reduced in individuals with (pre)diabetes. In addition, different measures of hyperglycemia are negatively associated with skin microvascular flowmotion., (© 2024 The Author(s). Microcirculation published by John Wiley & Sons Ltd.)

Background: The use of a self-adherent, elastic bandage is a practical way to dress finger injuries. Multiple reports describe iatrogenic injuries from elastic bandages, ranging from skin necrosis to finger gangrene, necessitating amputations. This study investigated whether elastic bandages can compromise digital perfusion by occluding arterial blood flow in healthy volunteers and evaluated the utility of pulse oximetry as a monitoring tool for digital perfusion. A technique for safe bandage application is proposed., Methods: A commercially available elastic bandage was wrapped around the index finger of 20 healthy volunteers at varying degrees of stretch. Digital perfusion measurements were carried out using photoelectric pulse transduction, laser Doppler flowmetry, and pulse oximetry. Intracompartmental pressure measurements were recorded using a separate in vitro experimental model., Results: Elastic bandages applied at maximum stretch did not change digital brachial index or pulse oximetry values, suggesting arterial blood flow was preserved distal to the bandage. Intracompartmental pressure measurements at maximum stretch remained below the systolic digital pressure. In contrast, superficial dermal perfusion fell to 32% of normal as measured by laser Doppler flow, at 100% bandage stretch., Conclusion: This study suggests a risk for iatrogenic injury when using elastic bandages for finger dressings. While arterial inflow was never compromised, pressures were high enough to occlude superficial venous outflow, which may begin at 20% bandage stretch. Pulse oximetry failed to detect changes distal to applied dressings, and we do not recommend it to detect digital vascular compromise in this setting., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Indicators (markers) of microcirculation stability (MCR) of the skin in symmetric areas of the head were studied in young (18-19-years-old) and elderly (60-80-years-old) male and female subjects. We performed synchronous MCR measurements of symmetrical areas of the head using laser Doppler flowmetry in 40 healthy volunteers (10 men and 10 women in each age group). Numerical values of stability markers (T1, T2, and ζ) and indicators of the right-left hemodynamic balance of the MCR (regression coefficients a1, a2, b1, b2) were obtained using the previously developed computational and experimental methods. The coefficients a2 and b2 that determine the contribution of the right MCR bed to the right-left hemodynamic balance were higher in elderly men than in young men, while in young and elderly women, no significant differences in the values of these coefficients were revealed. In young men, coefficients a2 and b2 were lower than in young women, while in elderly subjects, the sex differences in these coefficients were leveled. Young men have lower stability markers than women, while in elderly subjects, these stability markers were similar in men and women. No significant age and sex differences in the level of perfusion of the symmetrical temporal regions were found. The results attest to low stability of MCR in young men in comparison with young women and similar stability in old age, which, apparently, can be explained by the influence of sex hormones on the regulation of human cardiovascular functions., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

The effect of intraperitoneal injection of LPS (pyrogenal, 100 μg/kg) on the asymmetry of the right-left hemodynamic balance of microcirculation (MCR) was studied in 10 male Wistar rats. Synchronous measurements of the MCR parameters of the outer surface of the symmetrical areas of the tail base were carried out by laser Doppler flowmetry. The coefficients of asymmetry of the regression relationships between changes in perfusion of each of the observation sides and the initial perfusion values of both the eponymous and opposite observation sides, as well as the mean values and coefficients of perfusion variation of the studied areas, were analyzed. Injection of pyrogenal changed parameters of the asymmetry of the right-left hemodynamic balance of MCR in comparison with the initial values. One hour after the injection of pyrogenal, the contribution of the left MCR bed to the right-left hemodynamic balance increased, and the right one decreased. At the same time, the value of the perfusion variation coefficient decreased on the left and increased on the right. The shift of the hemodynamic balance towards the left MCR bed led to significant increase in blood supply to the left MCR pool after pyrogenal injection. The results of the studies indicate a stress type of reaction of the animal body to the injected drug., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: To investigate the association between pretreatment blood flow velocity in the choroid and optic nerve head (ONH) and retinal oxygen metabolism in the acute uveitic phase and the development of 'sunset glow fundus' in Vogt-Koyanagi-Harada (VKH) disease., Methods: Retrospective analysis of 41 patients (82 eyes). Laser speckle flowgraphy and retinal oximetry measurements were performed at the presentation. The main outcome measure was the development of 'sunset glow fundus'., Results: Twenty patients (40 eyes) presented in the phase preceding anterior segment inflammation (early presentation), and 21 patients (42 eyes) presented with anterior segment inflammation (late presentation). In ONH, mean blur rate (MBR)-vessel, representing blood flow velocity in retinal vessels, was significantly lower in the late presentation group, while choroidal MBR was not significantly different. The late presentation group had significantly lower oxygen saturation in retinal venules, a higher arteriovenous oxygen saturation difference and a smaller calibre of retinal arterioles compared with the early presentation group. Eyes that subsequently developed 'sunset glow fundus' had significantly lower ONH MBR-vessels, lower oxygen saturation in retinal venules, a higher arteriovenous oxygen saturation difference and a smaller calibre of retinal arterioles compared with eyes without 'sunset glow fundus'. ONH MBR-vessel had a significant negative correlation with arteriovenous oxygen saturation difference and a significant positive correlation with calibre of retinal arterioles., Conclusions: In the acute uveitic phase of VKH disease, the development of 'sunset glow fundus' is associated with pretreatment reduced retinal blood flow velocity, calibre of retinal arterioles and oxygen saturation in retinal venules, as well as an increased arteriovenous oxygen saturation difference., (© 2024 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Prior work has yet to determine whether the reduction of dietary nitrate (NO 3 - ) to NO, via the enterosalivary pathway, may modify cutaneous vascular conductance (CVC) responses to local heating in older women. Changes occurring with the transition to menopause related to hormonal flux, increased adiposity, and/or decreased physical activity may further compound the negative influence of aging on nitric oxide (NO)-dependent CVC. Herein, we characterized changes in NO-dependent CVC following acute ingestion of 140 mL of NO 3 ). Red blood cell (RBC) flux was measured continuously via laser-Doppler flowmetry on the dorsal aspect of the forearm during local skin heating to 39 °C/44 °C before and 3 h after NO - -rich beetroot juice in 24 older women (age: 65 ± 5 y, BMI: 31.2 ± 3.7 kg/m 2 ). Red blood cell (RBC) flux was measured continuously via laser-Doppler flowmetry on the dorsal aspect of the forearm during local skin heating to 39 °C/44 °C before and 3 h after NO 3 - ingestion. NO-dependent changes in CVC were calculated as RBC flux/mean arterial blood pressure at 39 °C and normalized as a proportion of maximal CVC at 44 °C (%CVCmax). Changes (Δ) in fractional exhaled NO (FeNO) following NO 3 - ingestion were used an index of NO bioavailability. Despite increased FeNO (+81 ± 70 %, P < 0.001), %CVCmax at 39 °C was reduced (-16 ± 10 %, P < 0.001) following NO 3 - ingestion. A greater reduction in %CVCmax was weakly to moderately associated with higher body fat% (r = 0.45 [0.05-0.72], P = 0.029), central adiposity% (r = 0.50 [0.13-0.75], P = 0.012), neutrophil% (r = 0.42 [0.02-0.70], P = 0.041), and higher neutrophil to lymphocyte ratio (r = 0.49 [0.11-0.75], P = 0.016). These findings demonstrate a single dose of dietary NO 3 - does not promote CVC responses to local heating in sedentary older women with overweight and obesity. Correlation with multiple biomarkers suggest systemic inflammation may be involved., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Flowmotion analysis of the microcirculatory blood flow is a method to extract information about the vessel regulatory function. It has previously shown promise when applied to measurements during a post-occlusive reactive hyperemia. However, the reperfusion peak and the following monotonic decline introduces false low frequencies that should not be interpreted as rhythmic vasomotion effect., Aim: To develop and validate a robust method for flowmotion analysis of post-occlusive reactive hyperemia signals., Method: The occlusion-induced reperfusion response contains a typical rapid increase followed by a monotonic decline to baseline. A mathematical model is proposed to detrend this transient part of the signal to enable further flowmotion analysis. The model is validated in 96 measurements on healthy volunteers., Results: Applying the proposed model corrects the flowmotion signal without adding any substantial new false flowmotion components., Conclusion: Future studies should use the proposed method or equivalent when analyzing flowmotion during post-occlusive reactive hyperemia to ensure valid results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Pressure ulcers are a common adverse event in healthcare. To date, no flowmetry studies have been conducted to compare hyperoxygenated fatty acids (HFA) vs. extra-virgin olive oil (EVOO) in alleviating this condition. To determine and evaluate the effect of the application of HFA vs. EVOO on tissue oxygenation and perfusion in heels under pressure, in healthy persons and in hospitalised patients. Two-phase experimental study. Phase 1 will be conducted with healthy subjects, using a randomised, open study design, evaluating an intrasubject control group. Phase 2 will focus on hospitalised subjects, with a randomised, open study group vs. a control group. This Project is undertaken to identify the mechanisms that intervene in the genesis of pressure ulcers and to determine whether there are differences in outcomes between the application of HFA vs. EVOO as a preventive measure The results of this study are of economic importance (due to the price difference between the products used) and will also impact on usual clinical practice for patients with impaired mobility and liable to suffer from pressure ulcers, by considering an alternative to established preventive measures. • There are no previous studies about the effect of HFA and EVOO in tissue oxygenation and perfusion in heels under pressure. • This study may have economic impact due to the price difference between preventive products used. • This Project is undertaken to identify the mechanisms that intervene in the genesis of pressure ulcers. [ABSTRACT FROM AUTHOR]

Several trials have shown that paclitaxel drug-coated balloons (DCBs) significantly reduce restenosis rates. However, some reports have shown distal embolisms occurring after DCBs. No study has analyzed the clinical outcomes of patients with DCB-induced distal embolism. This study aimed to investigate the clinical outcomes of DCB-induced distal embolism in patients with femoropopliteal artery disease. Between February 2018 and April 2019, consecutive patients (n = 32) who presented with de novo femoropopliteal artery disease and underwent endovascular therapy using DCB were retrospectively reviewed in a single-center study. Patients were divided into two groups based on whether distal embolism was detected using laser doppler flowmetry (DEL group) or not (non-DEL group). Baseline characteristics and 1-year clinical outcomes were compared between the groups. DEL was found in 44% of limbs (DEL group: n = 15, non-DEL group: n = 19). Below-the-knee arterial runoff ≤ 1 (p = 0.033), popliteal lesion (p = 0.044), ambulation difficulty (p = 0.021), and previous history of coronary artery disease (p = 0.013) were identified as predictive factors of DEL. Procedural factors, reference vessel diameter, lesion length, and total drug amount were not predictive of DEL. The overall target lesion restenosis (TLR) rate was 17.4% (n = 5). The TLR rate was not significantly different between the DEL and non-DEL groups (13.3% vs. 15.8%, p = 0.55). Severe calcification was the only significant factor for TLR (4.2% vs. 40.0%, p = 0.02). Among patients with femoropopliteal disease, there was no difference in 1-year clinical outcome between patients who underwent DEL and those who did not. [ABSTRACT FROM AUTHOR]

A fiber-optic probe-based instrument, designed for assessment of parameters related to microcirculation, red blood cell tissue fraction (fRBC), oxygen saturation (SO2), and speed resolved perfusion, has been evaluated using state-of-the-art tissue phantoms. The probe integrates diffuse reflectance spectroscopy (DRS) at two source-detector separations and laser Doppler flowmetry, using an inverse Monte Carlo method for identifying the parameters of a multilayered tissue model. Here, we characterize the accuracy of the DRS aspect of the instrument using (1) liquid blood phantoms containing yeast and (2) epidermis-dermis mimicking solid-layered phantoms fabricated from polydimethylsiloxane, titanium oxide, hemoglobin, and coffee. The root-mean-square (RMS) deviations for fRBC for the two liquid phantoms were 11% and 5.3%, respectively, and 11% for the solid phantoms with highest hemoglobin signatures. The RMS deviation for SO2 was 5.2% and 2.9%, respectively, for the liquid phantoms, and 2.9% for the solid phantoms. RMS deviation for the reduced scattering coefficient (μs'), for the solid phantoms was 15% (475 to 850 nm). For the liquid phantoms, the RMS deviation in average vessel diameter (D) was 1  μm. In conclusion, the skin microcirculation parameters fRBC and SO2, as well as, μs' and D are estimated with reasonable accuracy.

This study aims to compare skin perfusion pressure measurements (SPP) at midfoot and below knee level performed with a novel laser Doppler flowmetry (LD) probe with a reference method based on photo plethysmography (PP). It includes 40 patients referred with known or suspected peripheral arterial disease. The SPP was performed with both devices. Blinded re-interpretation of the SPP measurements was carried out by three observers and a consensus quality score was provided for each measurement. SPP >40 mmHg was considered a clinically relevant cut-off. This study evaluates a total of 48 paired measurements of the midfoot and 54 below knee. The two methods agreed in overall diagnostic classification in 80 of 102 measurements (78%) with both methods showing SPP ≥40 mmHg in 21 cases, and both methods showing SPP <40 mmHg in 59 cases. Of the 22 participants with disagreement (22%) in overall classification, 15 had measurements within the range of 30-50 mmHg, and 7 with a clinically relevant disagreement with one device showing SPP <30 mmHg and the other ≥40 mmHg. Analysis of inter observer variation for the LD readings showed an intraclass correlation coefficient of 0.880 (95% CI: 0.807 to 0.929, p- value <0.05) at midfoot, and 0.933 (95% CI: 0.894 to 0.959, p-value <0.05) at below knee level. The novel probe based on LD showed good correlation with PP in absolute pressures, sufficient agreement in overall disease classification as well as good to excellent reliability in terms of inter observer variation. [ABSTRACT FROM AUTHOR]

Overestimation of blood pressure (BP) resulting from medial artery calcification (MAC) is a cause of pseudoresistant hypertension. In this condition, there is no noninvasive way to reliably assess the BP. We report the case of a 62-year-old man who had a four-limb MAC, hypertension despite five antihypertensive molecules, and significant orthostatic hypotension following the addition of the fifth drug. Hypotension symptoms resolved after discontinuation of two treatments. Subsequently, measurement of finger SBP (FSBP) by laser Doppler flowmeter (LDF) was used to estimate upper-limb SBP. While the brachial SBP was greater than 170 mmHg, the FSBP was always less than 140 mmHg. In the absence of upper-limb artery disease, by evidencing the discrepancy between FSBP and brachial SBP, LDF-obtained FSBP could be a reliable tool to ascertain pseudohypertension and monitor the antihypertensive treatment., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: During caries progression, dental pulp is increasingly pathologically affected. Since the accurate assessment of pulp is of vital importance in clinical decision-making, this study aimed to evaluate pulpal condition in the early stages of caries via laser Doppler (LD) flowmetry and histologic analysis and determine their agreement., Methods: Fourteen patients with severe dental crowding were included. Prior to extractions and orthodontic treatment, dental pulp condition of 52 premolars was evaluated via LD flowmetry. Teeth were assessed for the presence of caries and lesions were graded according to the International Caries Detection and Assessment System (ICDAS). After extractions, teeth were split and histologically stained for endothelial cells with anti-von Willebrand factor and Movat pentachrome for collagen. Volume densities of vessels (V vasc ) and collagen were calculated., Results: There was a significant negative correlation between LD flow and V vasc of the dental pulp with ICDAS grade. Pulpal LD flow and V vasc in teeth with the initial lesion were increased, decreasing with progressing stages of caries. A significant positive correlation between the the pulpal LD flow and V vasc , and a negative correlation of LD flow with collagen fibre density were noted., Conclusions: Caries affects the physiology of the dental pulp, initially with increasing vascularity, and decreasing vascularity at later stges of caries progression. Collagen contents increase with grades of ICDAS. LD flow shows good agreement with the histologic constitution of the dental pulp. Use of clinical measurements of pulpal LD flow could provide a good noninvasive indication of pulpal vascular state and its health., Competing Interests: Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Current methods used to assess gingivitis are qualitative and subjective. We hypothesized that gingival perfusion measurements could provide a quantitative metric of disease severity. We constructed a compact laser speckle imaging (LSI) system that could be mounted in custom-made oral molds. Rigid fixation of the LSI system in the oral cavity enabled measurement of blood flow in the gingiva. In vitro validation performed in controlled flow phantoms demonstrated that the compact LSI system had comparable accuracy and linearity compared to a conventional bench-top LSI setup. In vivo validation demonstrated that the compact LSI system was capable of measuring expected blood flow dynamics during a standard postocclusive reactive hyperemia and that the compact LSI system could be used to measure gingival blood flow repeatedly without significant variation in measured blood flow values (p

Laser speckle imaging (LSI) enables measurement of relative changes in blood flow in biological tissues. We postulate that a point-of-care form factor will lower barriers to routine clinical use of LSI. Here, we describe a first-generation handheld LSI device based on a tablet computer. The coefficient of variation of speckle contrast was < 2% after averaging imaging data collected over an acquisition period of 5.3 s. With a single, experienced user, handheld motion artifacts had a negligible effect on data collection. With operation by multiple users, we did not identify any significant difference (p > 0.05) between the measured speckle contrast values using either a handheld or mounted configuration. In vivo data collected during occlusion experiments demonstrate that a handheld LSI is capable of both quantitative and qualitative assessment of changes in blood flow. Finally, as a practical application of handheld LSI, we collected data from a 53-day-old neonate with confirmed compromised blood flow in the hand. We readily identified with LSI a region of diminished blood flow in the thumb of the affected hand. Our data collectively suggest that handheld LSI is a promising technique to enable clinicians to obtain point-of-care measurements of blood flow.

ObjectivesTo determine whether stability/accuracy of post-occlusive LDF following shortened, one-minute blood flow occlusion, increases in the post-exercise state or by averaging multiple measurements.MethodsSix healthy adults (3F) underwent LDF eight times at rest and following exercise, assessing post-occlusive (one-minute occlusion) reactive hyperemia in the cutaneous microcirculation of the forefinger. Measured variables included: pre- and post-occlusion steady-state perfusion (Plat1, Plat2), maximum post-occlusive perfusion (Max), PkT, and the ratio Max/Plat1.ResultsStability/accuracy of all variables improved performing measurements after exercise (p

Background and aimsFor more than 4 decades endoscopists have relied on ulcer stigmata for risk stratification and as a guide to hemostasis. None used arterial blood flow underneath stigmata to predict outcomes. For patients with severe peptic ulcer bleeding (PUB), we used a Doppler endoscopic probe (DEP) for (1) detection of blood flow underlying stigmata of recent hemorrhage (SRH), (2) quantitating rates of residual arterial blood flow under SRH after visually directed standard endoscopic treatment, and (3) comparing risks of rebleeding and actual 30-day rebleed rates for spurting arterial bleeding (Forrest [F] IA) and oozing bleeding (F IB).MethodsProspective cohort study of 163 consecutive patients with severe PUB and different SRH.ResultsAll blood flow detected by the DEP was arterial. Detection rates were 87.4% in major SRH-spurting arterial bleeding (F IA), non-bleeding visible vessel (F IIA), clot (F IIB)-and were significantly lower at 42.3% (P < .0001) for an intermediate group of oozing bleeding (F IB) or flat spot (F IIC). For spurting bleeding (F IA) versus oozing (F IB), baseline DEP arterial flow was 100% versus 46.7%, residual blood flow detected after endoscopic hemostasis was 35.7% versus 0%, and 30-day rebleed rates were 28.6% versus 0% (all P < .05).Conclusions(1) For major SRH versus oozing or spot, the arterial blood flow detection rate by the DEP was significantly higher, indicating a higher rebleed risk. (2) Before and after endoscopic treatment, spurting (F IA) PUB had significantly higher rates of blood flow detection than oozing (F IB) PUB and a significantly higher 30-day rebleed rate. (3) The DEP is recommended as a new endoscopic guide with SRH to improve risk stratification and potentially definitive hemostasis for PUB.

SARS‐CoV‐2 is causing devastation both in human lives and economic resources. When the world seems to start overcoming the pandemics scourge, the threat of long‐term complications of COVID‐19 is rising. Reports show that some of these long‐term effects may contribute to the main cause of morbimortality worldwide: the vascular diseases. Given the evidence of damage in the endothelial cells due to SARS‐CoV‐2 and that endothelial dysfunction precedes the development of arteriosclerosis, the authors propose to measure endothelial function around 6–12 months after acute disease in hypertensive patients, especially if they have other cardiovascular risk factors or overt vascular disease. The methods the authors propose are cost‐effective and can be made available to any hypertension unit. These methods could be the "in vivo" assessment of endothelial function by flow mediated vasodilatation after ischemia by Laser‐Doppler flowmetry and the measurement of plasma free circulating DNA and microparticles of endothelial origin. [ABSTRACT FROM AUTHOR]

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Background: Oral mucositis (OM) is an inflammation of the oral mucosa due to cancer therapy that compromises the patient’s quality of life. Laser Doppler flowmetry (LDF) is a non-invasive method to monitor microvascular blood flow (BF) in real-time. Purpose: Develop a method to evaluate BF in the genian region cheek in patients undergoing chemotherapy by LDF and compare the degrees of OM and pain with evaluation of BF. Material and methods: Evaluation of OM was performed using the World Health Organization (WHO) and Oral Mucositis Assessment Scale (OMAS) scales and the visual analog scale for pain evaluation. For flowmetry analysis, a laser Doppler flowmeter (moorVMSTM™, 780 nm wavelength and VP3 probe), fixed by an acrylic resin support was used; VP3 probe was positioned on the genian region and the patient’s head was stabilized with a neck pillow for an accurate measurement. The Wilcoxon test was used to compare the flowmetry results at the studied times. The Pearson correlation coefficient was used to evaluate relationships between BF and the WHO, OMAS and visual analog scales. Results: Eleven patients of both sexes, aged between 30 and 78 years, with OM were included. An increase in cutaneous BF was observed at the initial times of OM, with progressive reduction during the chemotherapy cycle. There was a statistical difference (p

Critical limb ischemia (CLI) is a state of severe peripheral artery disease, with no effective treatment. Cell therapy has been investigated as a therapeutic tool for CLI, and pericytes are promising therapeutic candidates based on their angiogenic properties. We firstly generated highly proliferative and immunosuppressive pericyte-like cells from embryonic stem (ES) cells. In order to enhance the angiogenic potential, we transduced the basic fibroblast growth factor (bFGF) gene into the pericyte-like cells and found a significant enhancement of angiogenesis in a Matrigel plug assay. Furthermore, we evaluated the bFGF-expressing pericyte-like cells in the previously established chronic hindlimb ischemia model in which bone marrow-derived MSCs were not effective. As a result, bFGF-expressing pericyte-like cells significantly improved blood flow in both laser Doppler perfusion imaging (LDPI) and dynamic contrast-enhanced MRI (DCE-MRI). These findings suggest that bFGF-expressing pericyte-like cells differentiated from ES cells may be a therapeutic candidate for CLI., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Experimental preeclampsia (ePE) has been shown to have worsened outcome from stroke. We investigated the effect of low-dose aspirin, known to prevent preeclampsia, on stroke hemodynamics and outcome, and the association between the vasoconstrictor and vasodilator cyclooxygenase products thromboxane A 2 and prostacyclin., Methods and Results: Middle cerebral artery occlusion was performed for 3 hours with 1 hour of reperfusion in normal pregnant rats on day 20 of gestation and compared with ePE treated with vehicle or low-dose aspirin (1.5 mg/kg per day). Multisite laser Doppler was used to measure changes in cerebral blood flow to the core middle cerebral artery and collateral vascular territories. After 30 minutes occlusion, phenylephrine was infused to increase blood pressure and assess cerebral blood flow autoregulation. Infarct and edema were measured using 2,3,5-triphenyltetrazolium chloride staining. Plasma levels of thromboxane A 2 , prostacyclin, and inflammatory markers in plasma and cyclooxygenase levels in cerebral arteries were measured. ePE had increased infarction compared with normal pregnant rats ( P <0.05) that was reduced by aspirin ( P <0.001). ePE also had intact cerebral blood flow autoregulation and reduced collateral perfusion during induced hypertension that was also prevented by aspirin. Aspirin increased prostacyclin in ePE ( P <0.05) without reducing thromboxane B 2 , metabolite of thromboxane A 2 , or 8-isoprostane-prostaglandin-2α, a marker of lipid peroxidation. There were no differences in cyclooxygenase levels in cerebral arteries between groups., Conclusions: Low-dose aspirin in ePE reduced infarction that was associated with increased vasodilator prostacyclin and improved collateral perfusion during induced hypertension. The beneficial effect of aspirin on the brain and cerebral circulation is likely multifactorial and worth further study.

Background:  Lower extremity trauma often necessitates reconstruction with flap transfer. One of the reconstructive goals is a thin soft tissue coverage with appropriate contour. Therefore, a secondary debulking of the flap is usually performed., Methods:  Debulking through conventional lipectomy is compared with liposuction followed by excision of the defatted flap excess. Demographic data, surgical details, and postoperative outcomes are compared and analyzed. The perfusion dynamics of the flaps undergoing liposuction debulking are studied by means of perioperative indocyanine green fluorescence angiography, as well as postoperative laser Doppler imaging., Results:  Patients undergoing lipectomy ( n  = 69; 57.5%) or liposuction ( n  = 51; 42.5%) debulking had a similar rate of postoperative complications. Partial necrosis was observed in 7.2% (lipectomy) versus 7.8% (liposuction) of flaps. Fluorescence angiography showed a substantial decrease in flap perfusion following the infiltration with an epinephrine-containing tumescent solution (74.3% ± 8.2% prior to infiltration versus 16.8% ± 7.1% after infiltration; p  < 0.001), resulting in a dark flap appearance. Laser Doppler imaging confirmed the hypoperfusion on postoperative day 1., Conclusion:  Secondary debulking of a lower extremity flap can be safely and efficiently performed through liposuction combined with peripheral excision of the defatted flap in a single stage. Perfusion studies may show a misleading hypoperfusion of the defatted flap, which does not accurately predict subsequent necrosis or complications., Competing Interests: None declared., (Thieme. All rights reserved.)

Purpose: To evaluate retinal blood flow (RBF) regulation in response to RBF stress in maturity-onset diabetes of the young type 3 (MODY3) pigs., Study Design: Case-control study., Methods: MODY3 pigs (diabetes mellitus [DM] group, n = 8) transfected with the human mutant hepatocyte nuclear factor-1⍺ and normal pigs of the same age (normal group, n = 8) were used as subjects. After confirming DM onset, the experiment was performed under inhalation anesthesia with isoflurane at 2 months of age before the cataract progressed. Ocular blood flow was assessed by calculating the optic papillary mean blur rate using laser speckle flowgraphy, modified for pig eye measurements. After baseline ocular blood flow measurements, flicker stimulation (12 Hz, 3 min) was applied, and ocular blood flow was measured over time., Results: Blood glucose was 81.8 ± 5.1 mg/dL in the normal group and 311.4 ± 23.1 mg/dL in the DM group (mean ± standard error). The percent change in ocular blood flow at 3 min after flicker stimulation was +31.0 ± 10.9% in the normal group and -6.6 ± 6.5% in the DM group compared to the preload value, and the difference was statistically significant (Mann-Whitney test, P = 0.015)., Conclusion: RBF response to flicker stimulation is reduced at 2 months of age in MODY3 pigs, suggesting that retinal neurovascular coupling is impaired from the early onset of DM., (© 2024. Japanese Ophthalmological Society.)

Addressing the existing gaps in our understanding of sex- and strain-dependent disparities in renal microhemodynamics, this study conducted an investigation into the variations in renal function and related biological oscillators. Using the genetically diverse mouse models BALB/c, C57BL/6, and Kunming, which serve as established proxies for the study of renal pathophysiology, we implemented laser Doppler flowmetry conjoined with wavelet transform analyses to interrogate dynamic renal microcirculation. Creatinine, urea, uric acid, glucose, and cystatin C levels were quantified to investigate potential divergences attributable to sex and genetic lineage. Our findings reveal marked sexual dimorphism in metabolite concentrations, as well as strain-specific variances, particularly in creatinine and cystatin C levels. Through the combination of Mantel tests and Pearson correlation coefficients, we delineated the associations between renal functional metrics and microhemodynamics, uncovering interactions in female BALB/c mice for creatinine and uric acid, and in male C57BL/6 mice for cystatin C. Histopathologic examination confirmed an augmented microvascular density in female mice and elucidating variations in the expression of estrogen receptor β among the strains. These data collectively highlight the influence of both sex and genetic constitution on renal microcirculation, providing an understanding that may inform the etiologic exploration of renal ailments., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background/aim: To examine the relationship between baseline blood flow biomarkers and long-term open-angle glaucoma (OAG) progression., Methods: 112 patients with early to moderate OAG (mean age 64.9±11.0 years; 68 female) were evaluated at baseline and every 6 months from 2008 to 2013. Biomarkers of retinal capillary blood flow were assessed by Heidelberg retinal flowmetry. Functional disease progression was monitored via Humphrey visual field examinations, defined as two consecutive visits with a mean deviation decrease ≥2 decibels and/or Advanced Glaucoma Intervention Study score increase ≥2 compared with baseline. Structural progression was monitored with optical coherence tomography and Heidelberg retinal tomograph, defined as two consecutive visits with retinal nerve fibre layer thickness decrease ≥8% and/or horizontal or vertical cup/disk ratio increase ≥0.2 compared with baseline. Mixed-model analysis of covariance was used to test for significant change from baseline to 5-year follow-up. Times to functional and structural progression were analysed using Cox proportional hazards models., Results: Lower HRF retinal capillary blood flow in the superior retina was significantly associated with structural progression (p=0.0009)., Conclusion: In our OAG sample, baseline lower retinal capillary perfusion in the superior retina was predictive of structural progression after 5 years., Trial Registration Number: NCT01145911., Competing Interests: Competing interests: There are no competing interests. Professor Alon Harris would like to disclose that he received remuneration from AdOM, Qlaris, Cipla for serving as a consultant, and he serves on the board of AdOM and Qlaris. Professor Alon Harris holds an ownership interest in AdOM, Oxymap, Qlaris and SlitLed. All relationships listed above are pursuant to Icahn School of Medicine’s policy on outside activities. The contribution of the author Francesco Oddone was supported by Fondazione Roma and by the Italian Ministry of Health. None of the other authors listed have any financial disclosures., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Orthognathic surgery has the potential to compromise the vitality of the teeth. This paper aims to assess changes in pulp blood flow (PBF) and pulp sensibility (PS) of the anterior dentition following orthognathic surgery and to assess the influence of the proximity of the surgical osteotomy on the PBF and/or PS., Methods: Twenty-six patients undergoing orthognathic surgery (Le Fort I or bilateral sagittal split osteotomy [BSSO]) were compared to sixteen control patients treated by fixed appliances only using Laser Doppler flowmeter (LDF) and thermal testing (CO2 snow). Surgery patients were tested at T1 (presurgery), T2 (4-5 weeks postsurgery), T3 (3 months postsurgery), and T4 (6 months postsurgery). Control patients were tested at T1 (pretreatment), T2 (6 months posttreatment), T3 (12 months posttreatment), and T4 (18 months posttreatment). Differences between the maxilla and mandible were assessed., Results: No differences in PBF or PS were recorded in the control group. In the surgery group, both jaws followed the same pattern after surgery, an initial decrease at T2 followed by a gradual recovery to pretreatment PBF levels with no significant difference between T1 versus T4 in both jaws. No difference in PBF was observed between the maxilla and mandible at any testing time interval., Conclusions and Clinical Implications: PBF and PS of the anterior dentition was severely affected immediately postsurgery, followed by a gradual increase to full recovery. This pattern of recovery was exhibited in both jaws. A negative sensibility response or discoloration should not be seen as an indication of irreversible ischemic pulp changes. Monitoring for at least 6 months or using LDF as a confirmatory test is required before any irreversible endodontic treatment is to be considered., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

The pathophysiological mechanism behind complications associated with postmastectomy radiotherapy (PMRT) and subsequent implant-based breast reconstruction are not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion and saturation in the skin after mastectomy and assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate - MN). Skin microvascular perfusion and oxygenation >2 years after PMRT were measured using white light diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) in the irradiated chest wall of 31 women with the contralateral breast as a control. In the non-irradiated breast, the perfusion after application of MN (median 0.84, 25th-75th centile 0.59-1.02 % RBC × mm/s) was higher compared to the irradiated chest wall (median 0.51, 25th-75th centile 0.21-0.68 % RBC × mm/s, p < 0.001). The same phenomenon was noted for saturation (median 91 %, 25th-75th centile 89-94 % compared to 89 % 25th-75th centile 77-93 %, p = 0.001). Eight of the women (26%) had a ≥10 % difference in skin oxygenation between the non-irradiated breast and the irradiated chest wall. These results indicate that late microvascular changes caused by radiotherapy of the chest wall significantly affect skin perfusion and oxygenation., Competing Interests: Declaration of competing interest Fredriksson is part-time employed by Perimed, AB, which is developing products related to research described in this publication. None of the other authors has disclosable conflicts of interests., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background and Objectives: Orthodontic tooth movement is associated with inflammatory responses. The aim of this study was to identify gingival microcirculation using laser Doppler flowmetry in patients with orthodontic treatment. Materials and Methods: A longitudinal pilot study was performed. The participants were selected using a non-probability consecutive sampling. Of the twenty-five subjects, a total of six (four women and two men) complied with the criteria. Before and during the treatment, the oral hygiene index, gingival index, probing depth, level of epithelial attachment, and gingival microcirculation were evaluated with laser Doppler flowmetry (integrated parameters: 1. integrated primary basal flow (IPBF), 2. integrated total secondary real flow (ITSRF), and 3. difference between integration (DBI)) in all of the participants). Results: (a) An increase in gingival blood flow was identified at all time intervals with different arches during orthodontic treatment. (b) The IPBF and ITSRF (with treatment) identified after 20 min (treatment initial stage) were compared with the different time intervals, and we observed an increase in gingival perfusion at the 24th, 48th, and 72nd hours in some arches. (c) In the DBI, we found statistically significant differences (p < 0.005) in the Nitinol group of 0.016 inches among all the time intervals (24 h, 48 h, and 72 h) within the 30-day interval, observing a flow increase three times greater than the basal flow after 30 days. Conclusions: Healthcare professionals must identify the inflammatory processes in treatment to observe and discontinue use of harmful methods in clinical practice. [ABSTRACT FROM AUTHOR]

Neural activity is closely coupled with energy metabolism but details of the association remain to be identified. One basic area involves the relationships between neural activity and the main supportive substrates of glucose and lactate. This is of fundamental significance for the interpretation of non-invasive neural imaging. Here, we use microelectrodes with high spatial and temporal resolution to determine simultaneous co-localized changes in glucose, lactate, and neural activity during visual activation of the cerebral cortex in the cat. Tissue glucose and lactate concentration levels are measured with electrochemical microelectrodes while neural spiking activity and local field potentials are sampled by a microelectrode. These measurements are performed simultaneously while neurons are activated by visual stimuli of different contrast levels, orientations, and sizes. We find immediate decreases in tissue glucose concentration and simultaneous increases in lactate during neural activation. Both glucose and lactate signals return to their baseline levels instantly as neurons cease firing. No sustained changes or initial dips in glucose or lactate signals are elicited by visual stimulation. However, co-localized measurements of cerebral blood flow and neural activity demonstrate a clear delay in the cerebral blood flow signal such that it does not correlate temporally with the neural response. These results provide direct real-time evidence regarding the coupling between co-localized energy metabolism and neural activity during physiological stimulation. They are also relevant to a current question regarding the role of lactate in energy metabolism in the brain during neural activation. Dynamic changes in energy metabolites can be measured directly with high spatial and temporal resolution by use of enzyme-based microelectrodes. Here, to examine neuro-metabolic coupling during brain activation, we use combined microelectrodes to simultaneously measure extracellular glucose, lactate, and neural responses in the primary visual cortex to visual stimulation. We demonstrate rapid decreases in glucose and increases in lactate during neural activation. Changes in glucose and lactate signals are transient and closely coupled with neuronal firing.

Surgical intervention of second degree burns is often delayed because of the difficulty in visual diagnosis, which increases the risk of scarring and infection. Non-invasive metrics have shown promise in accurately assessing burn depth. Here, we examine the use of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) for predicting burn depth. Contact burn wounds of increasing severity were created on the dorsum of a Yorkshire pig, and wounds were imaged with SFDI/LSI starting immediately after-burn and then daily for the next 4 days. In addition, on each day the burn wounds were biopsied for histological analysis of burn depth, defined by collagen coagulation, apoptosis, and adnexal/vascular necrosis. Histological results show that collagen coagulation progressed from day 0 to day 1, and then stabilized. Results of burn wound imaging using non-invasive techniques were able to produce metrics that correlate to different predictors of burn depth. Collagen coagulation and apoptosis correlated with SFDI scattering coefficient parameter [Formula: see text] and adnexal/vascular necrosis on the day of burn correlated with blood flow determined by LSI. Therefore, incorporation of SFDI scattering coefficient and blood flow determined by LSI may provide an algorithm for accurate assessment of the severity of burn wounds in real time.

Background and objectivePort-wine stain (PWS) birthmarks affect ∼22 million people worldwide. After several treatment sessions, complete disappearance of the PWS occurs in only ∼10% of treated patients. There is a need to develop a new strategy to improve the efficacy of each treatment session and the overall treatment outcome. The study objective was to determine how intraoperative measurements of blood flow correlate with treatment response assessed several weeks post treatment.Study design/materials and methodsWe employed Laser Speckle Imaging (LSI) to measure intraoperative blood-flow dynamics. We collected data from 24 subjects undergoing laser therapy for facial PWS birthmarks. Photographs were taken before treatment and at a follow-up visit, and analyzed by two expert observers.ResultsIntraoperative LSI enables real-time monitoring of blood-flow dynamics in response to laser treatment and can inform clinicians on the need for focused re-treatment. The degree of PWS blanching achieved is positively correlated with the log-transformed acute blood-flow reduction (P = 0.022).ConclusionLSI is a simple, intraoperative monitoring tool during laser therapy of PWS birthmarks. LSI provides a single value for blood flow that correlates well with the degree of blanching achieved with laser therapy.

A critical need exists for a robust method that enables early discrimination between superficial-partial and deep-partial thickness burn wounds. In this study, we report on the use of laser speckle imaging (LSI), a simple, non-invasive, optical imaging modality, to measure acute blood flow dynamics in a preclinical burn model. We used a heated brass comb to induce burns of varying severity to nine rats and collected raw speckle reflectance images over the course of three hours after burn. We induced a total of 12 superficial-partial and 18 deep-partial thickness burn wounds. At 3h after burn we observed a 28% and 44% decrease in measured blood flow for superficial-partial and deep-partial thickness burns, respectively, and that these reductions were significantly different (p=0.00007). This preliminary data suggests the potential role of LSI in the clinical management of burn wounds.

BACKGROUND: The role of microcirculatory disorders is progressively being accepted in the pathogenesis of cardiovascular diseases. OBJECTIVE: The purpose of current study is to assess whether we can consider skin microcirculation disorders as a biomarker of cardiovascular events. METHODS: Group 1 consisted of healthy volunteers (n = 31); group 2 (n = 42) consisted of patients with diseases that increase the risk of cardiovascular events; group 3 (n = 39) included patients with the history of cardiovascular events. Skin microcirculation measurement was performed using laser Doppler flowmetry during the heating test. RESULTS: LDF parameters reflecting the rapid response of microcirculation to heating ("Slope 120 s" and "Slope 180 s") significantly differed in three groups (p < 0.05). A decrease in the "Slope 180 s" parameter less than 0.5 PU/s is associated with cardiovascular events (sensitivity 69.2%, specificity 66.7%; the area under the ROC curve, 0.667; 95% confidence interval [CI], 0.545–0.788, p = 0.01). Multivariable logistic regression analysis revealed that "Slope 180 s≤0.5 PU/s" was significantly related to cardiovascular events (adjusted odds ratio = 3.9, p = 0.019, CI 95% 1.2–12). CONCLUSIONS: Reduced reactivity of the skin microcirculation may be useful as a biomarker of severe damage to the cardiovascular system and is promising as a risk factor for cardiovascular events. [ABSTRACT FROM AUTHOR]