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"Microcirculation"
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A randomised study of the impact of the SGLT2 inhibitor dapagliflozin on microvascular and macrovascular circulation
by
Jumar, Agnes
,
Friedrich, Stefanie
,
Bramlage, Peter
in
Aged
,
Angiology
,
Benzhydryl Compounds - pharmacology
2017
Background
The sodium–glucose cotransporter 2 inhibitor, dapagliflozin, has been shown to improve diabetic control and reduce blood pressure in patients with type 2 diabetes mellitus. Its effects on micro- and macrovascular structure and function have not yet been reported.
Methods
This was a prospective, single-centre, placebo-controlled, double-blind, randomised crossover phase IIIb study conducted between March 2014 and February 2015. After a 4-week run-in/washout phase, patients (N = 59) received 6 weeks of either dapagliflozin 10 mg or placebo once daily. They then underwent a 1-week washout before crossing over to the other treatment. Changes in retinal capillary flow (RCF) and arteriole remodelling were evaluated using scanning laser Doppler flowmetry, while micro- and macrovascular parameters in the systemic circulation were assessed using pulse wave analysis.
Results
Six weeks of dapagliflozin treatment resulted in improvements in diabetes control, including blood glucose and insulin resistance, and reduced office and 24-h ambulatory blood pressure values. RCF decreased from 324 AU at baseline to 308 AU after treatment with dapagliflozin (p = 0.028), while there was little difference after the placebo (318 AU; p = 0.334). Furthermore, the arteriole remodelling that was seen after the placebo phase was not evident after the dapagliflozin phase. Central systolic and diastolic blood pressure values were significantly lower after 6 weeks of dapagliflozin, by 3.0 and 2.2 mmHg, respectively (p = 0.035 and 0.020, respectively vs. baseline).
Conclusions
Six weeks of dapagliflozin treatment resulted in numerous beneficial effects. In addition to achieving superior diabetes control and blood pressure, parameters associated with the early stages of vascular remodelling were also improved.
Trial registration
http://www.clinicaltrials.gov
(NCT02383238)
Journal Article
Association of sublingual microcirculation parameters and endothelial glycocalyx dimensions in resuscitated sepsis
2019
Background
The endothelial glycocalyx (eGC) covers the luminal surface of the vascular endothelium and plays an important protective role in systemic inflammatory states and particularly in sepsis. Its breakdown leads to capillary leak and organ dysfunction. Moreover, sepsis-induced alterations of sublingual microcirculation are associated with a worse clinical outcome. The present study was performed to investigate the associations between eGC dimensions and established parameters of microcirculation dysfunction in sepsis.
Methods
This observational, prospective, cross-sectional study included 40 participants, of which 30 critically ill septic patients were recruited from intensive care units of a university hospital and 10 healthy volunteers served as controls. The established microcirculation parameters were obtained sublingually and analyzed according to the current recommendations. In addition, the perfused boundary region (PBR), an inverse parameter of the eGC dimensions, was measured sublingually, using novel data acquisition and analysis software (GlycoCheck™). Moreover, we exposed living endothelial cells to 5% serum from a subgroup of study participants, and the delta eGC breakdown, measured with atomic force microscopy (AFM), was correlated with the paired PBR values.
Results
In septic patients, sublingual microcirculation was impaired, as indicated by a reduced microvascular flow index (MFI) and a reduced proportion of perfused vessels (PPV) compared to those in healthy controls (MFI, 2.93 vs 2.74,
p
= 0.002; PPV, 98.53 vs 92.58,
p
= 0.0004). PBR values were significantly higher in septic patients compared to those in healthy controls, indicating damage of the eGC (2.04 vs 2.34,
p
< 0.0001). The in vitro AFM data correlated exceptionally well with paired PBR values obtained at the bedside (rs = − 0.94,
p
= 0.02). Both PBR values and microcirculation parameters correlated well with the markers of critical illness. Interestingly, no association was observed between the PBR values and established microcirculation parameters.
Conclusion
Our findings suggest that eGC damage can occur independently of microcirculatory impairment as measured by classical consensus parameters. Further studies in critically ill patients are needed to unravel the relationship of glycocalyx damage and microvascular impairment, as well as their prognostic and therapeutic importance in sepsis.
Trial registration
Retrospectively registered: Clinicaltrials.gov,
NCT03960307
Journal Article
Individualised exercise improves endothelial function in patients with rheumatoid arthritis
by
Veldhuijzen van Zanten, Jet JCS
,
Stavropoulos-Kalinoglou, Antonios
,
Koutedakis, Yiannis
in
Adult
,
Aerobics
,
Aged
2014
Background We investigated the effects of individualised combined resistance and aerobic exercise on microvascular and macrovascular function in rheumatoid arthritis (RA) patients. Methods Forty age-matched, gender-matched and body mass index (BMI)-matched patients were allocated to either an exercise group, receiving a 6 months tailored aerobic and resistance exercise intervention, or controls receiving only information about the benefits of exercise. Participants were assessed for microvascular (acetylcholine (Ach) and sodium nitroprusside (SNP)) and macrovascular (flow-mediated dilatation (FMD) and glyceryl trinitrate (GTN)) endothelial function, maximal oxygen uptake, disease activity and severity (C-reactive protein (CRP), disease activity score 28 and health assessment questionnaire). Data were collected at baseline, 3 months and at the end of the intervention (6 months). Results At baseline, demographic, anthropometric, disease-related characteristics and endothelial function parameters were similar between the exercise and control groups (p>0.05). Repeated measures analysis of variance revealed a significant improvement in endothelial function parameters at 3 (GTN: p<0.001) or 6 months (Ach: p=0.016, SNP: p=0.045, FMD: p=0.016) in the exercise but not in the control group. Generalised estimated equations detected that maximal oxygen uptake was a strong predictor for the observed changes in Ach (p=0.009) and GTN (p<0.001) whereas logCRP for SNP (p=0.017) and GTN (p=0.008). Conclusions An exercise programme designed to meet individual needs and physical abilities significantly improves microvascular and macrovascular function in parallel with disease-related characteristics in RA patients. The potential long-term beneficial effects of such interventions at reducing cardiovascular risk in these patients merit further exploration. Clinical Trial Registration ISRCTN50861407.
Journal Article
The effects of maximizing stroke volume versus maintaining preoperative resting cardiac index on oxygen delivery, oxygen consumption, and microcirculatory tissue perfusion in patients having major abdominal surgery: The exploratory randomized CUSTOM trial
by
Thomsen, Kristen K.
,
Saugel, Bernd
,
Krause, Linda
in
Abdomen
,
Abdomen - surgery
,
Abdominal surgery
2025
Mechanistic effects of intraoperative blood flow-guided hemodynamic therapy remain poorly understood. Therefore, we aimed to determine the effects of a) maximizing stroke volume and b) maintaining preoperative resting cardiac index on oxygen delivery, oxygen consumption, and sublingual and abdominal microcirculatory tissue perfusion in major abdominal surgery patients.
We randomized 76 patients to maximizing stroke volume, maintaining preoperative resting cardiac index, or routine care during and for the first 6 h after surgery. We measured oxygen delivery index, oxygen consumption index, sublingual microvascular flow index, and urethral perfusion index.
At the end of surgery and 6 h after surgery, the median (25th percentile, 75th percentile) oxygen delivery index was higher in patients assigned to stroke volume maximization (460 (404, 556) ml/min/m2 and 503 (466, 595) ml/min/m2) or to preoperative cardiac index maintenance (507 (460, 664) ml/min/m2 and 516 (403, 604) ml/min/m2) than in patients assigned to routine care (403 (338, 517) ml/min/m2 and 390 (351, 510) ml/min/m2). There were no important differences in oxygen consumption index and sublingual microvascular flow index among the three groups. The intraoperative average urethral perfusion index was slightly higher in patients assigned to stroke volume maximization or to preoperative cardiac index maintenance than in patients assigned to routine care.
In our trial, both maximizing stroke volume and maintaining preoperative resting cardiac index resulted in higher intraoperative and postoperative oxygen delivery index than routine care in major abdominal surgery patients. Large clinical trials are required to determine whether achieving higher perioperative oxygen delivery index translates into better outcomes.
•There are various strategies for intraoperative blood flow-guided management.•Their effects on oxygen delivery and tissue perfusion are unclear.•Stroke volume maximization increased oxygen delivery.•Maintaining preoperative cardiac index increased oxygen delivery.•Both strategies increased abdominal microcirculatory tissue perfusion.
Journal Article
Pharmacological Vasodilation Improves Insulin-Stimulated Muscle Protein Anabolism but Not Glucose Utilization in Older Adults
by
Timmerman, Kyle L.
,
Fujita, Satoshi
,
Lee, Jessica L.
in
Aged
,
Amino acids
,
Biological and medical sciences
2010
Skeletal muscle protein metabolism is resistant to the anabolic action of insulin in healthy, nondiabetic older adults. This defect is associated with impaired insulin-induced vasodilation and mTORC1 signaling. We hypothesized that, in older subjects, pharmacological restoration of insulin-induced capillary recruitment would improve the response of muscle protein synthesis and anabolism to insulin.
Twelve healthy, nondiabetic older subjects (71 ± 2 years) were randomized to two groups. Subjects were studied at baseline and during local infusion in one leg of insulin alone (Control) or insulin plus sodium nitroprusside (SNP) at variable rate to double leg blood flow. We measured leg blood flow by dye dilution; muscle microvascular perfusion with contrast enhanced ultrasound; Akt/mTORC1 signaling by Western blotting; and muscle protein synthesis, amino acid, and glucose kinetics using stable isotope methodologies.
There were no baseline differences between groups. Blood flow, muscle perfusion, phenylalanine delivery to the leg, and intracellular availability of phenylalanine increased significantly (P < 0.05) in SNP only. Akt phosphorylation increased in both groups but increased more in SNP (P < 0.05). Muscle protein synthesis and net balance (nmol · min(-1) · 100 ml · leg(-1)) increased significantly (P < 0.05) in SNP (synthesis, 43 ± 6 to 129 ± 25; net balance, -16 ± 3 to 26 ± 12) but not in Control (synthesis, 41 ± 10 to 53 ± 8; net balance, -17 ± 3 to -2 ± 3).
Pharmacological enhancement of muscle perfusion and amino acid availability during hyperinsulinemia improves the muscle protein anabolic effect of insulin in older adults.
Journal Article
Human-relevant near-organ neuromodulation of the immune system via the splenic nerve
by
Kirk, Joseph
,
Stathopoulou, Thaleia-Rengina
,
Rowles, Alison
in
Animal models
,
Animals
,
Autonomic nervous system
2021
Neuromodulation of immune function by stimulating the autonomic connections to the spleen has been demonstrated in rodent models. Consequently, neuroimmune modulation has been proposed as a new therapeutic strategy for the treatment of inflammatory conditions. However, demonstration of the translation of these immunomodulatory mechanisms in anatomically and physiologically relevant models is still lacking. Additionally, translational models are required to identify stimulation parameters that can be transferred to clinical applications of bioelectronic medicines. Here, we performed neuroanatomical and functional comparison of the mouse, rat, pig, and human splenic nerve using in vivo and ex vivo preparations. The pig was identified as a more suitable model of the human splenic innervation. Using functional electrophysiology, we developed a clinically relevant marker of splenic nerve engagement through stimulation-dependent reversible reduction in local blood flow. Translation of immunomodulatory mechanisms were then assessed using pig splenocytes and two models of acute inflammation in anesthetized pigs. The pig splenic nerve was shown to locally release noradrenaline upon stimulation, which was able to modulate cytokine production by pig splenocytes. Splenic nerve stimulation was found to promote cardiovascular protection as well as cytokine modulation in a high- and a low-dose lipopolysaccharide model, respectively. Importantly, splenic nerve–induced cytokine modulation was reproduced by stimulating the efferent trunk of the cervical vagus nerve. This work demonstrates that immune responses can be modulated by stimulation of spleen-targeted autonomic nerves in translational species and identifies splenic nerve stimulation parameters and biomarkers that are directly applicable to humans due to anatomical and electrophysiological similarities.
Journal Article
Hemodynamic coherence and the rationale for monitoring the microcirculation
2015
This article presents a personal viewpoint of the shortcoming of conventional hemodynamic resuscitation procedures in achieving organ perfusion and tissue oxygenation following conditions of shock and cardiovascular compromise, and why it is important to monitor the microcirculation in such conditions. The article emphasizes that if resuscitation procedures are based on the correction of systemic variables, there must be coherence between the macrocirculation and microcirculation if systemic hemodynamic-driven resuscitation procedures are to be effective in correcting organ perfusion and oxygenation. However, in conditions of inflammation and infection, which often accompany states of shock, vascular regulation and compensatory mechanisms needed to sustain hemodynamic coherence are lost, and the regional circulation and microcirculation remain in shock. We identify four types of microcirculatory alterations underlying the loss of hemodynamic coherence: type 1, heterogeneous microcirculatory flow; type 2, reduced capillary density induced by hemodilution and anemia; type 3, microcirculatory flow reduction caused by vasoconstriction or tamponade; and type 4, tissue edema. These microcirculatory alterations can be observed at the bedside using direct visualization of the sublingual microcirculation with hand-held vital microscopes. Each of these alterations results in oxygen delivery limitation to the tissue cells despite the presence of normalized systemic hemodynamic variables. Based on these concepts, we propose how to optimize the volume of fluid to maximize the oxygen-carrying capacity of the microcirculation to transport oxygen to the tissues.
Journal Article
Effect of Kuanxiong Aerosol on Perioperative Coronary Microcirculation in Patients with Unstable Angina Undergoing Elective PCI: A Pilot Randomized Controlled Trial
2025
Objective
To evaluate the immediate effect of Kuanxiong Aerosol (KXA) on perioperative coronary microcirculation in patients with unstable angina (UA) suffering from elective percutaneous coronary intervention (PCI).
Methods
From February 2021 to July 2023, UA inpatients who underwent PCI alone in the left anterior descending (LAD) branch were included. Random numbers were generated to divide patients into the trial group and the control group at a ratio of 1:1. The index of coronary microcirculation resistance (IMR) was measured before PCI, and the trial group was given two sprays of KXA, while the control group was not given. IMR was measured again after PCI, cardiac troponin I (cTnI) and creatine kinase isoenzyme-MB (CK-MB) were detected before and 24 h after surgery, and major cardiovascular adverse events (MACEs) were recorded for 30 days. The data statistics and analysis personnel were blinded.
Results
Totally 859 patients were screened, and 62 of them were involved into this study. Finally, 1 patient in the trial group failed to complete the post-PCI IMR and was excluded, 30 patients were included for data analysis, while 31 patients in the control group were enrolled in data analysis. There was no significant difference in baseline data (age, gender, risk factors, previous history, biochemical index, and drug therapy, etc.) between the two groups. In addition, differences in IMR, cTnI and CK-MB were not statistically significant between the two groups before surgery. After PCI, the IMR level of the trial group was significantly lower than that of the control group (19.56 ± 14.37
vs.
27.15 ± 15.03,
P
=0.048). Besides, the incidence of perioperative myocardial injury (PMI) was lower in the trial group, but the difference was not statistically significant (6.67%
vs.
16.13%,
P
=0.425). No MACEs were reported in either group.
Conclusions
KXA has the potential of improving coronary microvascular dysfunction. This study provides reference for the application of KXA in UA patients undergoing elective PCI. (Registration No. ChiCTR2300069831)
Journal Article
Comprehensive treatment of microvascular angina in overweight women – a randomized controlled pilot trial
2020
Coronary microvascular dysfunction (CMD) carries a poor cardiovascular prognosis and may explain angina in women without obstructive coronary artery disease (CAD). Currently, no evidence-based treatment for CMD exists. We investigated whether reducing cardiovascular risk factors improves symptoms and microvascular function in women with non-endothelial dependent CMD and no obstructive CAD.
We randomized 62 women aged 40-75, with body mass index (BMI) >25 kg/m2, angina ≥monthly, and coronary flow velocity reserve (CFVR) ≤2.5 to a 24-week intervention comprising low energy diet, exercise training, and optimized treatment of hypertension, dyslipidemia and diabetes or to control. Patients were assessed before randomization and after 24 weeks. Primary outcomes were CFVR assessed by transthoracic Doppler stress-echocardiography and angina burden by Seattle Angina Questionnaire (SAQ). Secondary outcomes were exercise capacity, body composition, glycemic control, myocardial function, and anxiety and depression symptoms.
Fifty-six participants (90%) completed the study. Median (IQR) age was 65.2 (57.1;70.7) years, BMI was 30.1 (28.4;32.7) kg/m2. The intervention resulted in relevant improvement in angina symptoms (9-21-point increase on SAQ-scales (all p<0.01)) but had no effect on CFVR (p = 0.468). Mean (CI) weight loss was 9.6 (7.80;11.48) kg, (p<0.0001). There was a significant mean (CI) decrease in depression symptoms = 1.16 (0.22;2.12), triglycerides = 0.52 (0.25;0.78) mmol/L, total cholesterol = 0.55 (0.12;0.98) mmol/L, and HbA1c in diabetics = 27.1 (1.60;52.6) mmol/mol but no effect on other secondary outcomes.
A major weight loss and intensified risk factor control resulted in significantly improved angina burden but no improvement of coronary microvascular function among women with microvascular angina.
Journal Article
Microcirculation properties of 20 % albumin in sepsis; a randomised controlled trial
by
Connolly, Elizabeth
,
Rodríguez, Alejandro
,
Martin-Loeches, Ignacio
in
Adolescent
,
Adult
,
Aged
2025
Sepsis and septic shock are associated with microcirculatory dysfunction, significantly impacting patient outcomes. This study aimed to evaluate the effects of a 20 % albumin bolus on microcirculation compared to crystalloid resuscitation in fluid-responsive patients (ClinicalTrials.govID:NCT05357339).
We conducted a single-centre randomised controlled trial, enrolling 103 patients (Albumin n = 52, Control n = 51). Fluid responsiveness was assessed, and fluid was administered in boluses of 100 ml to clinical effect. Microcirculation was measured using the Side stream Dark Field camera and AVA 4.3 software. Baseline characteristics, macrohaemodynamics, and microcirculation parameters were recorded. Three patients were excluded from analysis.
The final cohort comprised 100 patients, 35 (35 %) females with a mean age of 58 years (range: 18–86). The mean APACHE score was 28 (range: 7–45), and the mean SOFA score was 9.4 (range: 1–17). No significant differences in APACHE (26.24 vs. 29.4, p = 0.069) or SOFA (9.08 vs. 9.78, p = 0.32) scores were found for albumin and control group respectively. The albumin group had worse microcirculation at baseline but demonstrated significant improvements in microvascular density and activity at 15 min and 60 min (p < 0.005), while the control group exhibited no significant changes. Additionally, both groups were fluid responsive, with a mean pulse pressure variability of 17 % at admission. There were no significant differences in overall fluid balances, vasopressor days, length of ICU stay, or mortality between groups.
This study demonstrates that a 20 % albumin bolus significantly enhances microcirculation in fluid-responsive patients with septic shock. These findings underscore the potential benefits of targeted microcirculation therapy in critically ill patients.
[Display omitted]
•This is the largest randomised control trial studying microcirculation in and fluid bolus.•Using the gold-standard in real-time visualisation of the microcirculation, we show that 20 % albumin improves the microcirculation more than crystalloid.•We target fluid responsiveness and show that the microcirculation can be changed independently of macrohaemodynamic indicators, highlighting haemodynamic incoherence.•We show biological signal that albumin is improving microcirculation. This is important in the context of large multicentre trials of albumin as resuscitation fluid in ICU.
Journal Article