Laser Doppler Flowmetry Research Articles

Passive Ankle Plantarflexion Position and Skin Surface Blood Flow Adjacent to the Achilles Tendon.

Open repair of the Achilles tendon carries a risk of wound complications and infection. The Achilles tendon is covered by a thin layer of skin and subcutaneous tissue, which has a fragile blood supply. The full plantarflexion position may cause sustained blanching of the skin above the Achilles tendon. However, no reports have described the in vivo blood flow (BF) changes at the skin surface with ankle position. This study aimed to use laser Doppler flowmetry to evaluate the in vivo BF at the skin surface and thereby clarify the changes in BF with ankle position. The study cohort comprised 30 feet in 15 participants with no history of Achilles tendon rupture. Laser Doppler flowmetry was used to measure the BF at the skin surface above the medial Achilles tendon in the natural plantarflexion (NP) and full plantarflexion (FP) positions. In the NP and FP positions, the BF at 5 cm proximal to the calcaneal insertion (frequent site of Achilles tendon rupture) was 1.50 ± 0.32 and 0.97 ± 0.28 mL/min/100 g, respectively (P < .0001). The BF at the skin surface adjacent to the medial Achilles tendon at 5 cm proximal to the calcaneal insertion was significantly less in the FP position than the NP position.

Microcirculation in Hypertension: A Therapeutic Target to Prevent Cardiovascular Disease?

Arterial hypertension is a common condition worldwide and an important risk factor for cardio- and cerebrovascular events, renal diseases, as well as microvascular eye diseases. Established hypertension leads to the chronic vasoconstriction of small arteries as well as to a decreased lumen diameter and the thickening of the arterial media or wall with a consequent increased media-to-lumen ratio (MLR) or wall-to-lumen ratio (WLR). This process, defined as vascular remodeling, was firstly demonstrated in small resistance arteries isolated from subcutaneous biopsies and measured by micromyography, and this is still considered the gold-standard method for the assessment of structural alterations in small resistance arteries; however, microvascular remodeling seems to represent a generalized phenomenon. An increased MLR may impair the organ flow reserve, playing a crucial role in the maintenance and, probably, also in the progressive worsening of hypertensive disease, as well as in the development of hypertension-mediated organ damage and related cardiovascular events, thus possessing a relevant prognostic relevance. New non-invasive techniques, such as scanning laser Doppler flowmetry or adaptive optics, are presently under development, focusing mainly on the evaluation of WLR in retinal arterioles; recently, also retinal microvascular WLR was demonstrated to have a prognostic impact in terms of cardio- and cerebrovascular events. A rarefaction of the capillary network has also been reported in hypertension, which may contribute to flow reduction in and impairment of oxygen delivery to different tissues. These microvascular alterations seem to represent an early step in hypertension-mediated organ damage since they might contribute to microvascular angina, stroke, and renal dysfunction. In addition, they can be markers useful in monitoring the beneficial effects of antihypertensive treatment. Additionally, conductance arteries may be affected by a remodeling process in hypertension, and an interrelationship is present in the structural changes in small and large conductance arteries. The review addresses the possible relations between structural microvascular alterations and hypertension-mediated organ damage, and their potential improvement with antihypertensive treatment.

The microvascular bed of the skin of lower limbs in patients with intermittent lameness and coronary heart disease as a possible model of their myocardial microcirculation

Purpose: to assess possibility to extrapolate findings of skin microvascular bed examination in lower extremities with laser Doppler flowmetry in patients with obliterating atherosclerosis as a model of their myocardial microcirculation in coronary heart disease.Material and methods. Males with angiographically confirmed coronary heart disease (n = 70) and obliterating atherosclerosis in lower limbarteries (n = 74) were taken in the study. Microcirculation of the skin in the left forearm in the Zakharyin – Head zone in patients with coronaryheart disease and skin microcirculation in the foot of affected limb in patients with obliterating atherosclerosis of arteries of lower extremities were examined with laser Doppler flowmetry. The basal blood flow, amplitude-frequency spectrum of its oscillations, myogenic, neurogenic vascular tone and occlusion parameters were assessed as well. Comparison groups included 50 practically healthy males for the patients with coronary heart disease and 20 males – for the patients with obliterating atherosclerosis of arteries of lower extremities. Patients were examinedat the initial stage and in 2–3 weeks after endovascular restoration of blood flow in the myocardium and lower limbs.Results and discussion. At the initial research stage, the microcirculation picture in patients with coronary heart disease and obliterating ath-erosclerosis in lower extremities differed from that of healthy individuals by shifts covering all links of the microvascular bed and characterizedby constriction of the precapillary segment, a statistically significant decrease in median values of capillary blood flow by 17.5 and 43.1 %,microvascular blood flow reserve – by 11.2 and 31.0 %, as well as by the increase in arteriolovenular blood bypass – by 10.3 and 70.8 %,respectively. After the restoration of blood flow in lower extremities in patients with obliterating atherosclerosis, muscular pain disappeared,and the ankle-shoulder index got normalized. At the same time, one could observe a statistically significant increase in the capillary blood flow(+13.6 %), the increase of reserve potential in microvascular bed (+20.6 %) with the simultaneous decrease of vascular tone in the precapillarysegment (–15.1 %) and of the blood bypass index (–25.0 %). Better clinical picture after coronary angioplasty in patients with coronary heart disease was accompanied with a similar and unidirectional tendency to positive changes in the microvascular bed.Conclusion. As far as etiopathogenetic mechanisms and clinical manifestations of coronary heart disease and obliterating atherosclerosis in arteries of lower extremities have much in common and microcirculatory shifts in forearm and foot skin in these patients before and after angioplasty are unidirectional, all these allow to suggest that one can see similar changes in the myocardium microcirculatory system in patients with coronary heart disease. Thus, it opens possibilities to have a targeted medicamentous impact at the microvascular level.

Маркери психоемоційного стресу у жінок київського регіону в період російсько-української війни

War-related stress (WSR) leads to disruption of vital physiological functions, which can accelerate the development of age-related pathology and early mortality. Therefore, the study of the impact of SPV on the functioning of various body systems requires an in-depth analysis. The purpose of the study is to assess the level of psycho-emotional stress, anxiety, and depression and to investigate their influence on indicators of endothelial function, lipid, carbohydrate metabolism, autonomic nervous regulation of the cardiovascular system) in women of the Kyiv region during the Russian-Ukrainian war. 56 women aged 30-78 were examined (average age - 53.45 ± 1.6 years), who had been in the Kyiv region without permission since the beginning of the Russian-Ukrainian war (February 24, 2022). The control group consisted of 79 women aged 29-85 years, (average age - 56.46 ± 1.44 years), who were examined before the start of the Russian-Ukrainian war in 2018-2021. Anthropometric parameters, fasting plasma glucose level and standard oral glucose tolerance test (OGTT), serum lipid concentration, plasma cortisol level were determined. The function of the endothelium of microvessels was studied by the method of laser Doppler flowmetry in a sample with reactive post-occlusion hyperemia, the state of autonomic regulation of the cardiovascular system by the method of heart rhythm variability analysis. Psychoemotional state using the PLC-5 scale, Beck depression scale, Spielberger-Hanin test, the state of cognitive function was studied using the Montreal Cognitive Assessment (MoCA) A statistically significant increase in the level of cortisol, as an important marker of WSR, was revealed, compared to the control group. Excessive psycho-emotional stress of the body during the war is also evidenced by the predominance of the sympathetic link of autonomous nervous regulation in women. The development of endothelial dysfunction and the negative impact of WSR on lipid and carbohydrate metabolism were confirmed, which was combined with a decrease in mental performance indicators, an increase in the levels of personal and situational anxiety, and depression. An increase in the level of cortisol and the activity of the sympathetic link of the autonomic nervous system indicates the presence of chronic psychoemotional stress, which increases the levels of anxiety and depression, reduces the mental performance of women in war conditions and leads to the development of endothelial dysfunction, disorders of lipid and carbohydrate metabolism.

AT1-AA Infusion during Pregnancy Impairs CBF Autoregulation Postpartum.

Preeclampsia (PE), new-onset hypertension during pregnancy alongside organ dysfunction, is a leading cause of morbidity and mortality for the mother and fetus. PE women have activated B cells that produce agonistic autoantibodies to the angiotensin II type 1 receptor (AT1-AA). AT1-AA impairs cerebral blood flow (CBF) autoregulation during pregnancy. Although AT1-AA often remains elevated up to 8 years postpartum, AT1-AA's effect on CBF autoregulation postpartum is unknown. This study examined whether elevated AT1-AA during pregnancy impairs CBF autoregulation postpartum and if this was augmented by infusion of AT1-AA postpartum. AT1-AA was infused into 12-week-old timed-pregnant Sprague Dawley rats beginning on gestational day 14. Uterine artery resistance index (UARI) was measured on gestational day 18 as a measure of endothelial dysfunction associated with PE. Dams were allowed to deliver. One group was given a second infusion of AT1-AA (50% perinatal dose mimicking levels observed in postpartum PE women) at 9 weeks postpartum. After postpartum week 10, mean arterial pressure (MAP) was measured in conscious rats and CBF autoregulation was measured by laser Doppler flowmetry. AT1-AA during pregnancy increased UARI (P<0.05). AT1-AA during pregnancy did not affect MAP postpartum but did impair CBF autoregulation postpartum. Infusion of AT1-AA postpartum significantly elevated blood pressure (P<0.01) but did not further impair CBF autoregulation. This study demonstrates that circulating AT1-AA during pregnancy causes impairment of CBF autoregulation well into the postpartum period indicating that elevated AT1-AA leads to long-term cerebrovascular consequences. Targeting AT1-AA may prevent cerebrovascular effects associated with PE during pregnancy and postpartum.

Special features of microcirculatory disorders in patients with comorbid hypertension and rheumatoid arthritis

Background. During the recent years, there has been a steadily growing interest in the problems of microcirculatory disorders (MD) in patients with cardiological and rheumatological profile that is determined by a significant role of microcirculatory in the pathogenesis of these diseases.Objective. Analysis of the MD special features in patients with hypertension (HTN) and rheumatoid arthritis (RA).Design and methods. Patients matching the inclusion criteria by age (58,6 ± 6,4 years), debut (aged 45–64 years) and RA experience (7,2 ± 2,1 years) and HTN duration (11,2 ± 1,6 years) were divided into three groups: I group — 277 patients with stage II HTN; II group — 142 patients with stage II HTN and RA (in clinical and laboratory remission); group III — 112 patients with stage II HTN and RA (in clinical and laboratory exacerbation). The study of the microcirculatory bed was performed on an outpatient basis by laser Doppler flowmetry according to a standard technique. Results. Microcirculatory bed analysis in patients with HTN and RA showed the variability of indicators depending on gender characteristics, body weight and microcirculatory type. The study of the amplitude-frequency spectrum in women with stasis, in men with spastic and normocirculatory types of microcirculation showed an increase in neurogenic tone, endothelial activity and some decrease in the amplitude of oscillatory processes at the periphery.Conclusions. In patients with HTN and RA, changes at the microcirculatory level were determined, they manifested by an increase in adrenergic tone, spastic phenomena, endothelial activation, some decrease in blood flow variability and more pronounced vasomotor dysfunction that is not only the result of RA presence but its activity. RA in this situation could be regarded as a surrogate marker for the unfavorable course of HTN.

Применение лазерной допплеровской флоуметрии для оценки микроциркуляции почки до и после выполнения перкутанной нефролитотрипсии

Применение лазерной допплеровской флоуметрии для оценки микроциркуляции почки до и после выполнения перкутанной нефролитотрипсии

Poster 225: Acetabular Labral Blood Flow Using Laser Doppler Flowmetry Before &amp; After All- Arthroscopic Capsular Autograft Labral Reconstruction

Objectives: All-arthroscopic capsular autograft labral reconstruction has been proposed to repair complex or irreparable tears without the downside of autograft related donor-site morbidity. Cadaveric studies have suggested that the acetabular labrum receives its blood supply from radial branches of the periacetabular periosteal vascular ring that penetrate the hip capsule, with perfusion remaining intact in most hips exhibiting labral tears. Despite this, little is known about the exact course of blood flow to labral tissue or how surgical reconstruction of this region affects microvasculature during hip arthroscopy. The purpose of this study was to examine the effects of all-arthroscopic capsular autograft labral reconstruction on labral blood flow in vivo using laser doppler flowmetry (LDF) to measure microvascular perfusion. Methods: After obtaining institutional review board approval, patients ≥18 years old undergoing arthroscopic repair of the acetabular labrum by a single surgeon were consented between 2018-2022. Labral repair was performed via a previously published capsular autograft labral reconstruction technique. An LDF probe (Moor Instruments) continuously measured microvascular blood flow flux (perfusion units [PU]) within 1mm3 of surrounding labral tissue (Figure 1). LDF measurements were taken medial and lateral to the region of the tear before/after labral reconstruction and before/after labral elevation from the acetabular rim. The mean of flux measurements was expressed as a percent change from each patient’s baseline measurements. The percent change in labral perfusion was analyzed using student t-tests and one-way ANOVA using Tukey’s method for multiple comparisons. Associations between preoperative demographics and labral perfusion were analyzed using multiple regression analyses. Lending from previous literature, flux decreases ≥50% were considered clinically significant. Results: This study included 41 patients [24 males (58.5%) and 17 females (41.5%)] undergoing arthroscopic labral repair with capsular autograft reconstruction with mean [SD] age 31.3 [8.4] years, BMI 24.8 [3.3] kg/m2, lateral center edge angle (LCEA) 35.3 [4.9] degrees, Tönnis angle 5.8 [5.8] degrees, and mean arterial pressure 96.0 [10.9] mmHg. The mean [95% CI] percent change in blood flow following labral elevation was -9.24% [(-0.04) to (-18.1)]. Following labral reconstruction, the mean [95% CI] percent change in blood flow medially was -22.3% [(-11.9) to (-32.7)] and laterally -32.5% [(-23.6) to (-41.5)]. There was no significant difference between the changes in medial versus lateral perfusion (p=0.136) following repair. Unadjusted analyses stratifying for age, BMI, sex, type of impingement, Tönnis/Outerbridge class, amount of capsule used for augmentation, and suture technique revealed that none of these factors were correlated with significant differences in labral perfusion medially or laterally (p&gt;0.05; Table 1). Multiple regression analyses controlling for demographic and intra-operative variables demonstrated that BMI, LCEA, suture technique, age, mean arterial pressure were not significantly associated with changes in medial or lateral labral perfusion (p&gt;0.05; Table 2). Finally, all changes in flux were found to be significantly less than the 50% threshold, when comparing decreases following labral elevation (p&lt;0.001) and labral reconstruction medially (p&lt;0.001) and laterally (p&lt;0.001). Conclusions: While the vascular nature of the acetabular labrum has been described in literature, preservation of labral blood flow following arthroscopic labral repair has not yet been objectively reported. This study found that techniques to preserve native hip anatomy and vascular supply may adequately maintain perfusion to labral tissue and promote healing. While laser doppler flowmetry may be affected by secondary operative factors, careful measures were taken to standardize the in vivo environment during each measurement. Additionally, blood flow measurements are only limited time assessments with no ability to speculate if observed changes are permanent or temporary. Although this study cannot be generalized to all variations of labral repair/reconstruction, these results suggest that surgeons can employ techniques that preserve microvascular tissue perfusion. The use of capsular augmentation enables preservation of the donor-tissue blood supply with local tissue transfer, suggesting that current labral repair techniques can preserve labral perfusion. [Table: see text] [Table: see text]

Workload and sex effects in comprehensive assessment of cutaneous microcirculation.

Workload and sex-related differences have been proposed as factors of importance when evaluating the microcirculation. Simultaneous assessments with diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) enable a comprehensive evaluation of the microcirculation. The aim of the study was to compare the response between sexes in the microcirculatory parameters red blood cell (RBC) tissue fraction, RBC oxygen saturation, average vessel diameter, and speed-resolved perfusion during baseline, cycling, and recovery, respectively. In 24 healthy participants (aged 20 to 30years, 12 females), cutaneous microcirculation was assessed by LDF and DRS at baseline, during a workload generated by cycling at 75 to 80% of maximal age-predicted heart rate, and recovery, respectively. Females had significantly lower RBC tissue fraction and total perfusion in forearm skin microcirculation at all phases (baseline, workload, and recovery). All microvascular parameters increased significantly during cycling, most evident in RBC oxygen saturation (34% increase on average) and perfusion (9-fold increase in total perfusion). For perfusion, the highest speeds (>10mm/s) increased by a factor of 31, whereas the lowest speeds (<1mm/s) increased by a factor of 2. Compared to a resting state, all studied microcirculation measures increased during cycling. For perfusion, this was mainly due to increased speed, and only to a minor extent due to increased RBC tissue fraction. Skin microcirculatory differences between sexes were seen in RBC concentration and total perfusion.

Neuroprotective Effect of Platinum Nanoparticles Is Not Associated with Their Accumulation in the Brain of Rats.

Platinum nanoparticles (nPts) have neuroprotective/antioxidant properties, but the mechanisms of their action in cerebrovascular disease remain unclear. We investigated the brain bioavailability of nPts and their effects on brain damage, cerebral blood flow (CBF), and development of brain and systemic oxidative stress (OS) in a model of cerebral ischemia (hemorrhage + temporary bilateral common carotid artery occlusion, tBCAO) in rats. The nPts (0.04 g/L, 3 ± 1 nm diameter) were administered to rats (N = 19) intraperitoneally at the start of blood reperfusion. Measurement of CBF via laser Doppler flowmetry revealed that the nPts caused a rapid attenuation of postischemic hypoperfusion. The nPts attenuated the apoptosis of hippocampal neurons, the decrease in reduced aminothiols level in plasma, and the glutathione redox status in the brain, which were induced by tBCAO. The content of Pt in the brain was extremely low (≤1 ng/g). Thus, nPts, despite the extremely low brain bioavailability, can attenuate the development of brain OS, CBF dysregulation, and neuronal apoptosis. This may indicate that the neuroprotective effects of nPts are due to indirect mechanisms rather than direct activity in the brain tissue. Research on such mechanisms may offer a promising trend in the treatment of acute disorders of CBF.

Study of blood microcirculation in the area of purulent inflammatory process in patients with phlegmon of the maxillofacial region with the analyzer “LASMA PF”

The article is devoted to the assessment of the state of the microcirculatory bed of the skin in the purulent-inflammatory process in patients with phlegmon of the maxillofacial region who were treated in the maxillofacial department of the Moscow Pirogov State Clinical Hospital. Microcirculation parameters were recorded by laser Doppler flowmetry (LDF) with simultaneous temperature recording directly from the skin in the area of purulent-inflammatory infiltrate, by applying the apparatus of the analyzer «LASMA PF» to the patient’s skin. The diagnosis by the analyzer «LAZMA PF» is based on the simultaneous assessment of the activity of the tissue coenzyme of the reduced nicotinamide adenine dinucleotide (NADH) by fluorescence spectroscopy and indicators of microcirculation of blood flow by laser Doppler flowmetry. It is concluded that the differences obtained during the study between microcirculatory disorders in the purulent-inflammatory process and the healthy side indicate the need for drug therapy that regulates blood rheology and the state of the microcirculatory bed.

Simultaneous treatment for anal fissure and hemorrhoids

When using surgical approach to treatment for combined anal fissure and hemorrhoids doctor always faces the question of whether to divide the procedure into two sequential stages or to perform a simultaneous surgical intervention, and in which cases one or the other should be done. Purpose - to improve the results of treatment for patients with anal fissure in combination with chronic hemorrhoids by combining fissurectomy with transanal hemorrhoidal dearterialization (THD). Materials and methods. 177 patients with combination of anal fissure and hemorrhoids were studied. The Group I (GI) - fissure excision and hemorrhoidectomy, 60 patients. The Group II (GII) - anal fissure excision without surgery for hemorrhoids, 60 patients. The Group III (GIII) - proposed method used, 57 patients. Laser Doppler flowmetry was performed to assess blood flow intensity in fissure area. The assessment of treatment outcomes in patients was based on the following criteria: pain intensity, urinary retention in early postoperative period, postoperative wound suppuration, disease recurrence, iatrogenic incontinence, duration of postoperative hospital stay. Qualitative parameters are presented as the absolute number of cases (n) and their percentage (%). Comparison of these parameters between groups was performed using the Pearson’s χ2 test and the Fisher’s exact test. Statistical analysis was conducted by STATA 12.1 statistical package. Results. Pain intensity: GI - 8±1, GII - 6±2, GIII - 4±1. Urinary retention: GI - 19 (31.6%), GII - 8 (13%), GIII - 6 (10.5%). Wound suppuration: GI - 5 (8.3%), GII - 1 (1.7%), GIII - 1 (1.7%). Hospital stay (days): GI - 6±1.2, GII - 4±1.3, GIII - 3±1.1. Fissure recurrences: GI - 5 (8.3%), GII - 2 (3.3%), GIII - 1 (1.7%). Hemorrhoid recurrence: GI - 6 (10%), GIII - 2 (3.5%). Iatrogenic incontinence: GI - 4 (6.7%), GII - 1 (1.7%), GIII - 0. Significant decrease in relative risk of complications (by 88%) in GIII compared with GI - OR=0.12 (0.04-0.29), p=0.0001, and a tendency to reduction of complication risk by 15% compared with GII - OR=0.85 (0.29-2.4), p=0.734 was observed. Blood flow intensity (flowmetry results) in GII and GIII was comparable. Conclusions. Simultaneous anal fissure excision and THD can improve treatment outcomes. This method does not impair blood flow in the area of anal fissure. Proposed method is both radical and minimally invasive. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Sampling volume assessment for wearable multimodal optical diagnostic device.

The process and results of numerical Monte Carlo simulation of optical radiation propagation in laser Doppler flowmetry (LDF) and fluorescence spectroscopy (FS) channels of a wearable diagnostic multimodal device are described in this paper. To achieve the goal, a multilayer skin model with different parameters of blood and melanin content and different distances between sources and radiation receivers was designed. The changes in the sampling (diagnostic) volume depending on the anatomical features of the biological tissues, as well as on the technical parameters of the device were shown. Depending on the scattering media optical properties and the source-detector configuration of the device, the diagnostic volume can range from 2 to 7 mm3 . The obtained results allow the formation of specialized medical and technical requirements for wearable multimodal devices implementing LDF and FS channels.

Vascular response to the microcirculation in the fingertip by local vibration with varied amplitude.

Objectives: We investigated the effect of local vibration intensity on the vascular response to the microcirculation of the finger. Materials and methods: We performed hand-transmitted vibration experiments combined with laser Doppler flowmetry (LDF) to measure the blood perfusion signals of fingertips in the vibrated hand and the contralateral middle finger under the same frequency and different amplitude vibration, and to analyze the changes of microcirculatory blood perfusion levels in the fingers, and to investigate the effects of vibration stimulation on the endothelial, neural and myogenic regulatory frequency ranges of fingertips based on wavelet analysis. Furthermore, the transparent silicone films were fabricated and cultured with vascular endothelial cell (EC), which will undergo the local vibration with varied amplitude. And the expression of inflammatory factors was detected in the ECs. Results: Low-frequency vibration leads to a decreased blood flow in fingertip, and the degree of reduction in fingertip blood flow increases as the amplitude gradually increases, and the period required for blood flow to return to normal level after hand-transmitted vibration gradually increases. The decrease in blood flow is more pronounced in the vibrating hand than in the contralateral hand. In addition, nuclear factor-κB (NF-κB) expression increased significantly with the increase of vibration amplitude. Conclusion: High amplitude vibrations caused the inflammatory reaction of ECs which will lead to the altered endothelial regulatory activity. The endothelial regulatory activity is closely related to the blood perfusion in the microcirculation.

Effects of electroacupuncture on NLRP3/Caspase-1/GSDMD axis and neurological function in rats with cerebral ischemic reperfusion

To investigate the neuroprotective effect of electroacupuncture (EA) at "Quchi" (LI 11) and "Zusanli" (ST 36) in the rats with cerebral ischemic reperfusion and the potential mechanism of microglia pyroptosis. Sixty SD rats were randomly divided into a sham-operation group, a model group and an EA group, with 20 rats in each group. The Zea Longa method was employed to establish the rat model of the middle cerebral artery occlusion and reperfusion (MACO/R) in the left brain. In the EA group, since the 2nd day of modeling, EA was given at "Quchi" (LI 11) and "Zusanli" (ST 36) of right side with disperse-dense wave, 4 Hz/20 Hz in frequency and 0.2 mA in current intensity, 30 min each time, once a day for lasting 7 consecutive days. The reduction rate of cerebral blood flow was measured with laser Doppler flowmetry during operation. The neurological function of rats was observed using Zea Longa neurobehavioral score. The cerebral infarction volume was detected by TTC staining method. The microglia positive expression in the ischemic side of the cortex was detected with the immunofluorescence method. Under transmission electron microscope, the ultrastructure of cell in the ischemic cortex was observed. The mRNA expression levels of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cysteinyl aspartate specific proteinase-1 (Caspase-1) and gasdermin D (GSDMD) in the ischemic cortex were detected using real-time PCR. Compared with the sham-operation group, in the model group, the reduction rate of cerebral blood flow was increased during operation (P<0.001); Zea Longa neurobehavional score and the percentage of cerebral infarction volume were increased (P<0.001), the numbers of M1-type microglia marked by CD68+ and M2-type microglia marked by TMEM119+ were elevated in the ischemic cortex (P<0.001), the mRNA expression of NLRP3, ASC, Caspase-1 and GSDMD was increased (P<0.001, P<0.01); the cytomembrane structure was destroyed, with more cell membrane pores formed in the ischemic cortex. Compared with the model group, after intervention, Zea Longa neurobehavioral score and the percentage of cerebral infarction volume were reduced (P<0.05), the number of M1-type microglia marked by CD68+ was reduced (P<0.05) and the number of M2-type microglia marked by TMEM119+ was increased (P<0.05); and the mRNA expression of NLRP3, ASC, Caspase-1 and GSDMD was decreased (P<0.01, P<0.05) in the EA group. Even though the cytomembrane structure was incomplete, there were less membrane pores presented in the ischemic cortex in the EA group after intervention. The intervention with EA attenuates the neurological dysfunction and reduces the volume of cerebral infarction in the rats with cerebral ischemic reperfusion. The underlying mechanism is related to the inhibition of microglia pyroptosis through modulating NLRP3/Caspase-1/GSDMD axis.

Methyl Palmitate Modulated NMDA-Induced Cerebral Hyperemia in Hypertensive Rats

N-methyl-D-aspartate (NMDA) receptors were found to be dysfunctional in hypertensive rats. Methyl palmitate (MP) has been shown to diminish the nicotine-induced increase in blood flow in the brainstem. The aim of this study was to determine how MP modulated NMDA-induced increased regional cerebral blood flow (rCBF) in normotensive (WKY), spontaneously hypertensive (SHR), and renovascular hypertensive (RHR) rats. The increase in rCBF after the topical application of experimental drugs was measured using laser Doppler flowmetry. Topical NMDA application induced an MK-801-sensitive increase in rCBF in anesthetized WKY rats, which was inhibited by MP pretreatments. This inhibition was prevented by pretreatment with chelerythrine (a PKC inhibitor). The NMDA-induced increase in rCBF was also inhibited by the PKC activator in a concentration-dependent manner. Neither MP nor MK-801 affected the increase in rCBF induced by the topical application of acetylcholine or sodium nitroprusside. Topical application of MP to the parietal cortex of SHRs, on the other hand, increased basal rCBF slightly but significantly. MP enhanced the NMDA-induced increase in rCBF in SHRs and RHRs. These results suggested that MP had a dual effect on the modulation of rCBF. MP appears to play a significant physiological role in CBF regulation.

ID: 213709 Use of LSS to Characterize and Quantify Blood Flow Changes in Patients During SCS

Spinal cord stimulation (SCS) has been reported to impact peripheral blood flow when used to treat pain from a variety of conditions.1-4 Peripheral blood flow measurements can be obtained via laser Doppler flowmetry (LDF), photo-plethysmography (PPG), and transcutaneous oxygen pressure (TcPO2); each having their own technology-specific drawbacks.5,6 Laser speckle spectroscopy (LSS) is an alternative way to measure peripheral blood flow that may overcome the limitations of previous technologies by quantitatively measuring blood flow through the full volume of a digit, and producing a blood flow waveform in real time. Real-time changes in blood flow in response to SCS could be useful in determining the impact of stimulation beyond pain relief by modifying the underlying disease state or improving circulation where blood flow in an affected limb is impaired. The aim of this study is to gain experience with perfusion measurements in SCS patients, and to characterize and quantify blood flow with stimulation on versus off.

Comparative Analysis of Indicators of Microcirculation Stability in the Temporal Regions of the Head in Young Men and Women.

Indicators (markers) of microcirculation stability of the temporal regions of the head in young male and female subjects were studied. In 20 healthy volunteers aged 18-19 years (10 men and 10 women), synchronous measurements of the microcirculation of symmetrical temporal regions of the head were performed by laser Doppler flowmetry. Numerical values of stability markers (T1, T2, ζ) and parameters a1, a2, b1, b2 of the differential equation system describing oscillatory processes in the microcirculation system of the studied regions were obtained using the computational and experimental methodology developed by us earlier. It is shown that the right-left hemodynamic balance of microcirculation in men is maintained at the expense of the balance between the change in blood flow on the right and the initial value of blood flow on the left (coefficient b1) and in women, by the balance between the change in blood flow on the left and the initial value of blood flow on the right (coefficient a2). In women, the contribution of the right channel of the microcirculation to the right-left hemodynamic is significantly higher than in men. In general, the quantitative indicators (markers) of the stability of the microcirculation of the temporal regions of the head in women were higher than in men, which attests to higher stress resistance of the female organism in comparison with the male.

Assessment of Acetabular Labral Blood Flow Using Laser Doppler Flowmetry Before and After All-Arthroscopic Capsular Autograft Labral Reconstruction

Assessment of Acetabular Labral Blood Flow Using Laser Doppler Flowmetry Before and After All-Arthroscopic Capsular Autograft Labral Reconstruction

Nitric oxide‐mediated cutaneous microvascular function is not altered in middle‐aged‐to‐older adults following mild SARS‐CoV‐2 infection: A pilot study

We tested the hypothesis that post-COVID-19 adults (PC) would have impaired cutaneous nitric oxide (NO)-mediated vasodilation compared to controls (CON). We performed a cross-sectional study including 10 (10 F/0 M, 69 ± 7 years) CON and 7 (2 F/5 M, 66 ± 8 years) PC (223 ± 154 days post-diagnosis). COVID-19 symptoms severity (survey) was assessed (0-100 scale for 18 common symptoms). NO-dependent cutaneous vasodilation was induced by a standardized 42°C local heating protocol and quantified via perfusion of 15 mM NG-nitro-L-arginine methyl ester during the plateau of the heating response (intradermal microdialysis). Red blood cell flux was measured with laser-Doppler flowmetry. Cutaneous vascular conductance (CVC = flux/mm Hg) was presented as a percentage of maximum (28 mM sodium nitroprusside +43°C). All data are means ± SD. The local heating plateau (CON: 71 ± 23% CVCmax vs. PC: 81 ± 16% CVCmax , p = 0.77) and NO-dependent vasodilation (CON: 56 ± 23% vs. PC: 60 ± 22%, p = 0.77) were not different between groups. In the PC group neither time since diagnosis nor peak symptom severity (46 ± 18 AU) correlated with NO-dependent vasodilation (r < 0.01, p = 0.99 and r = 0.42, p = 0.35, respectively). In conclusion, middle-aged and older adults who have had COVID-19 did not have impaired NO-dependent cutaneous vasodilation. Additionally, in this cohort of PC, neither time since diagnosis nor symptomology were related to microvascular function.