Tiny clue reveals the general trend: a bibliometric and visualized analysis of renal microcirculation

BACKGROUND

Renal microcirculation plays a pivotal role in kidney function by maintaining structural and functional integrity, facilitating oxygen and nutrient delivery, and waste removal. However, a thorough bibliometric analysis in this area remains lacking. Therefore, we aim to provide valuable insights through a bibliometric analysis of renal microcirculation literature using the Web of Science database.

METHODS

We collected renal microcirculation-related publications from the Web of Science database from January 01, 1990, to December 31, 2022. The co-authorship of authors, organizations, and countries/regions was analyzed with VOSviewer1.6.18. The co-occurrence of keywords and co-cited references were analyzed using CiteSpace6.1.R6 software to generate visualization maps. Additionally, burst detection was applied to keywords and cited references to forecast research hotspots and future trends.

RESULTS

Our search yielded 7462 publications, with the American Journal of Physiology-Renal Physiology contributing the most articles. The United States, Mayo Clinic, and Lerman Lilach O emerged with the highest publication count, indicating their active collaborations. 'Type 2 diabetes' was the most significant keyword cluster, and 'diabetic kidney disease' was the largest cluster of cited references. 'Cardiovascular outcome' and 'diabetic kidney diseases' were identified as keywords in their burst period over the past three years.

CONCLUSION

Our bibliometric analysis illuminates the contours of nephrology and microcirculation research, revealing a landscape ripe for challenges and the seeds of future scientific innovation. While the trends discerned from the literature emerging opportunities in diagnostic innovation, renal microcirculation research, and precision medicine interventions, their translation to clinical practice is anticipated to be a deliberate process.

Single-cell transcriptomes and chromatin accessibility of endothelial cells unravel transcription factors associated with dysregulated angiogenesis in systemic sclerosis

OBJECTIVES

Vasculopathy emerges early in systemic sclerosis (SSc) and links to endothelial cell (EC) injury and angiogenesis. Understanding EC transcriptomes and epigenomes is crucial for unravelling the mechanisms involved.

METHODS

Transcriptomes and chromatin accessibility were assessed by single-cell RNA sequencing and single-nucleus transposase-accessible chromatin sequencing. Immunofluorescent staining of skin and proteomics assay were employed to confirm the altered SSc EC phenotypes. Gain-of-function assay was used to evaluate the effects of ETS transcription factors on human dermal ECs (hDECs).

RESULTS

Both control and SSc ECs shared transcriptomic signatures of vascular linages (arterial, capillary and venous ECs) and lymphatic ECs. Arterial ECs in SSc showed reduced number and increased expression of genes associated with apoptosis. Two distinct EC subpopulations, tip and proliferating ECs, were markedly upregulated in SSc, indicating enhanced proangiogenic and proliferative activities. Molecular features of aberrant SSc-ECs were associated with disease pathogenesis and clinical traits of SSc, such as skin fibrosis and digital ulcers. Ligand-receptor analysis demonstrated altered intercellular networks of SSc EC subpopulations with perivascular and immune cells. Furthermore, the integration of open chromatin profiles with transcriptomic analysis suggested an increased accessibility of regulatory elements for ETS family transcription factors in SSc ECs. Overexpression of ETS genes in hDECs suggested ELK4, ERF and ETS1 may orchestrate arterial apoptosis and dysregulated angiogenesis in SSc.

CONCLUSIONS

This study unveils transcriptional and chromatin alterations in driving endovascular dysregulation in SSc, proposing ELK4, ERF and ETS1 as novel targets in ECs for addressing vascular complications in the condition.

Computed tomography myocardial perfusion imaging to detect myocardial ischemia in patients with anxiety and obstructive coronary heart disease post-exposure to mental stressors

This study aims to measure myocardial blood flow (MBF) using dynamic CT- myocardial perfusion imaging (CT-MPI) combined with mental stressors in patients with obstructive coronary artery disease (OCAD) and in patients with anxiety and no obstructive coronary artery disease (ANOCAD). A total of 30 patients with OCAD with 30 patients with ANOCAD were included in this analysis. Using the 17-segment model, the rest and stress phase MBF of major coronary arteries in participants were recorded respectively. Compared with ANOCAD patients, OCAD patients were more likely to have localized reduction of MBF (p < 0.05). For patients with ANOCAD, both global MBF and MBF of the main coronary arteries in the stress phase were lower than those in the rest phase (all p < 0.05), but there was no significant difference in MBF among the main coronary arteries in the rest or stress phase (p = 0.25, p = 0.15). For patients with OCAD, the MBF of the target area was lower than that of the non-target area in both the rest and stress phase, and the MBF of the target area in the stress phase was lower than that in the rest phase (all p < 0.05). However, there was no significant difference in MBF between the rest or stress phase in the non-target area (p = 0.73). Under mental stress, the decrease in MBF in ANOCAD patients was diffuse, while the decrease in MBF in OCAD patients was localized. Dynamic CT-MPI combined with mental stressors can be used to detect MBF changes in anxiety patients.

Longitudinal analysis of microcirculatory parameters in gingival tissues after tooth extraction in patients with different risk profiles for wound healing disorders - a pilot study

OBJECTIVES

We aimed to establish a risk profile for intraoral wound healing disorders based on measurements of microcirculation in gingival tissues.

MATERIALS AND METHODS

Oxygen saturation (SO2) and blood flow in gingival tissues were measured with tissue spectrometry and laser doppler spectroscopy in 37 patients before/after tooth extractions. Patients were assigned to four groups: anamnestically and periodontally healthy patients (n = 7), anamnestically healthy but suffering from periodontitis (n = 10), anamnestically healthy but smoking and suffering from periodontitis (n = 10) and suffering from diabetes and periodontitis (n = 10). Measurements were performed at three different time points: Baseline measurement (T0), one day post extractionem (p.e.) (T1) and seven days p.e. (T2).

RESULTS

Baseline SO2 values were higher in control patients (p = .038). This effect was most evident in comparison to smokers suffering from periodontitis (p = .042), followed by diabetics suffering from periodontitis (p = .09). An opposite trend was seen for blood flow. Patients suffering from periodontitis demonstrated higher blood flow values (p = .012). Five patients, which belonged to the group of smokers suffering from periodontitis, showed clinically a delayed wound healing.

CONCLUSION

Differences in SO2 and blood flow of gingival tissue could be detected in different groups of patients with existing periodontitis compared to control patients.

CLINICAL RELEVANCE

Lower baseline SO2 values could be a warning signal for possible wound healing disorders after oral surgery.

Toxic side-effects of diaspirin cross-linked human hemoglobin are attenuated by the apohemoglobin-haptoglobin complex

Alpha-alpha diaspirin-crosslinked human hemoglobin (DCLHb or ααHb) was a promising early generation red blood cell (RBC) substitute. The DCLHb was developed through a collaborative effort between the United States Army and Baxter Healthcare. The core design feature underlying its development was chemical stabilization of the tetrameric structure of hemoglobin (Hb) to prevent Hb intravascular dimerization and extravasation. DCLHb was developed to resuscitate warfighters on the battlefield, who suffered from life-threatening blood loss. However, extensive research revealed toxic side effects associated with the use of DCLHb that contributed to high mortality rates in clinical trials. This study explores whether scavenging Hb and heme via the apohemoglobin-haptoglobin (apoHb-Hp) complex can reduce DCLHb associated toxicity. Awake Golden Syrian hamsters were equipped with a window chamber model to characterize the microcirculation. Each group was first infused with either Lactated Ringer's or apoHb-Hp followed by a hypovolemic infusion of 10% of the animal's blood volume of DCLHb. Our results indicated that animals pretreated with apoHb-Hb exhibited improved microhemodynamics vs the group pretreated with Lactated Ringer's. While systemic acute inflammation was observed regardless of the treatment group, apoHb-Hp pretreatment lessened those effects with a marked reduction in IL-6 levels in the heart and kidneys compared to the control group. Taken together, this study demonstrated that utilizing a Hb and heme scavenger protein complex significantly reduces the microvasculature effects of ααHb, paving the way for improved HBOC formulations. Future apoHb-Hp dose optimization studies may identify a dose that can completely neutralize DCLHb toxicity.

Association Between Early Patient Characteristics and IgE-Mediated Allergy in the Perioperative Setting

BACKGROUND

Early recognition of perioperative anaphylaxis, a life-threatening, usually IgE-mediated, immediate hypersensitivity, is essential, but bedside diagnosis is not always straightforward because clinical presentation may vary.

OBJECTIVES

To describe early characteristics of perioperative immediate hypersensitivity, with special attention to cutaneous phenotypes, and identify risk factors for IgE-mediated allergy.

METHODS

We retrospectively analyzed data from adults with suspected perioperative immediate hypersensitivity who were investigated in two academic medical centers. Multivariable logistic regression was conducted to evaluate associations among patient, clinical, and paraclinical characteristics and IgE-mediated allergy.

RESULTS

Of 145 enrolled patients, 99 (68.3%) and 46 (31.7%) were respectively categorized in the IgE-mediated allergy and non-allergy groups. Cutaneous vasoconstriction phenotype (pallor, piloerection, thelerethism, and sweating with or without cyanosis) occurring within minutes (or even 1 minute) of drug exposure was strongly associated with IgE-mediated allergy (adjusted odds ratio [aOR] = 28.02; 95% CI, 4.41-305.18). IgE-mediated allergy was always life-threatening in this setting. Other early factors associated with allergy were low end-tidal carbon dioxide 25 mm Hg or less (aOR = 5.45; 95% CI, 2.39-26.45), low mean arterial pressure 60 mm Hg or less (aOR = 3.82; 95% CI, 1.28-17.31), and early cutaneous vasodilation (erythema, urticaria, and/or angioedema) (aOR = 2.78; 95% CI, 0.73-20.54). Late cutaneous vasodilation after restoration of hemodynamics corroborated the diagnosis of allergy (aOR = 23.67; 95% CI, 4.94-205.09). The best-fit model including three readily available variables (cutaneous phenotype involving the three modalities [reference lack of cutaneous signs], low mean arterial pressure, and low end-tidal carbon dioxide) had an area under the curve of 0.91.

CONCLUSIONS

Cutaneous vasoconstriction phenotype is associated with the strongest risk of life-threatening allergy and thus may be regarded as pathognomonic of perioperative IgE-mediated anaphylaxis.

Sedation with propofol and isoflurane differs in terms of microcirculatory parameters: A randomized animal study using dorsal skinfold chamber mouse model

OBJECTIVE

This study aimed to explore the effects of sedative doses of propofol and isoflurane on microcirculation in septic mice compared to controls. Isoflurane, known for its potential as a sedation drug in bedside applications, lacks clarity regarding its impact on the microcirculation system. The hypothesis was that propofol would exert a more pronounced influence on the microvascular flow index, particularly amplified in septic conditions.

MATERIAL AND METHODS

Randomized study was conducted from December 2020 to October 2021 involved 60 BALB/c mice, with 52 mice analyzed. Dorsal skinfold chambers were implanted, followed by intraperitoneal injections of either sterile 0.9 % saline or lipopolysaccharide for the control and sepsis groups, respectively. Both groups received propofol or isoflurane treatment for 120 min. Microcirculatory parameters were obtained via incident dark-field microscopy videos, along with the mean blood pressure and heart rate at three time points: before sedation (T0), 30 min after sedation (T30), and 120 min after sedation (T120). Endothelial glycocalyx thickness and syndecan-1 concentration were also analyzed.

RESULTS

In healthy controls, both anesthetics reduced blood pressure. However, propofol maintained microvascular flow, differing significantly from isoflurane at T120 (propofol, 2.8 ± 0.3 vs. isoflurane, 1.6 ± 0.9; P < 0.001). In the sepsis group, a similar pattern occurred at T120 without statistical significance (propofol, 1.8 ± 1.1 vs. isoflurane, 1.2 ± 0.7; P = 0.023). Syndecan-1 levels did not differ between agents, but glycocalyx thickness index was significantly lower in the isoflurane-sepsis group than propofol (P = 0.001).

CONCLUSIONS

Propofol potentially offers protective action against microvascular flow deterioration compared to isoflurane, observed in control mice. Furthermore, a lower degree of sepsis-induced glycocalyx degradation was evident with propofol compared to isoflurane.

A study on six different protocols

OBJECTIVES

Laser Doppler Flowmetry (LDF) is a non-invasive technique for the assessment of tissue blood flow, but increased reproducibility would facilitate longitudinal studies. The aim of the study was to assess the interday reproducibility of Laser Doppler Flowmetry (LDF) at rest, at elevated local temperatures, and with the use of the vasodilator Methyl Nicotinate (MN) in six interconnected protocols for the measurement of the blood supply to the microvascular bed of the gingiva.

METHODS

Ten healthy volunteers were included. Interweek LDF measurements with custom-made acrylic splints were performed. Six protocols were applied in separate regions of interest (ROI): 1; basal LDF, 2; LDF with thermoprobe 42 °C, 3; LDF with thermoprobe 45 °C, 4; LDF with thermoprobe 42 °C and MN, 5; LDF with thermoprobe 45 °C and MN and 6; LDF with MN.

RESULTS

Intra-individual reproducibility was assessed by the within-subject coefficient of variation (wCV) and the intraclass correlation coefficient (ICC). Basal LDF measurements demonstrated high reproducibility with wCV 11.1 in 2 min and 10.3 in 5 min. ICC was 0.9 and 0.92. wCV after heat and MN was 4.9-10.3 and ICC 0.82-0.93. The topically applied MN yielded increased blood flow.

CONCLUSION

This is the first study evaluating the reproducibility of basal LDF compared to single or multiple vasodilatory stimuli in gingiva. Multiple collector fibers probe and stabilizing acrylic splints are recommended. Vasodilatory stimulation showed a tendency toward higher reproducibility. Furthermore, MN yields vasodilation in gingiva.

A mathematical model of tissue axial and radial diffusion in the microvasculature for intravascular microscopy and phosphorescence quenching data

This study aims to extend earlier Krogh Cylinder Models of an oxygen profile by considering axial diffusion and analytically solving Fick's Law Partial Differential Equation with novel boundary conditions via the separation of variables. We next prospectively collected a total of 20 animals, which were randomly assigned to receive either fresh or two-week-old stored red blood cell (RBC) transfusions and PQM oxygen data were measured acutely (90 min) or chronically (24 h). Transfusion effects were evaluated in vivo using intravital microscopy of the dorsal skinfold window chamber in Golden Syrian Hamsters. Hamsters were initially hemorrhaged by 50% of total blood volume and resuscitated 1-h post hemorrhage. PQM data were subsequently collected and fit the derived 2D Krogh cylinder model. Systemic hemodynamics (mean arterial pressure, heart rate) were similar in both pre and post-transfusion with either stored or fresh cells. Transfusion with stored cells was found to impair axial and radial oxygen gradients as quantified by our model and consistent with previous studies. Specifically, we observed a statistically significant decrease in the arteriolar tissue radial oxygen gradient after transfusion with stored RBCs at 24 h compared with fresh RBCs (0.33 ± 0.17 mmHg μ m-1 vs, 0.14 ± 0.12 mmHg μ m-1; p = 0.0280). We also observed a deficit in the arteriolar tissue oxygen gradient (0.03 ± 0.01 mmHg μ m-1 fresh vs. 0.018 ± 0.007 mmHg μ m-1 stored; p = 0.0185). We successfully derived and validated an analytical 2D Krogh cylinder model in an animal model of microhemodynamic oxygen diffusion aberration secondary to storage lesions.

In vivo pilot study into superficial microcirculatory characteristics of colorectal adenomas using novel high-resolution magnifying endoscopy with blue laser imaging

BACKGROUND

No studies have yet been conducted on changes in microcirculatory hemodynamics of colorectal adenomas in vivo under endoscopy. The microcirculation of the colorectal adenoma could be observed in vivo by a novel high-resolution magnification endoscopy with blue laser imaging (BLI), thus providing a new insight into the microcirculation of early colon tumors.

AIM

To observe the superficial microcirculation of colorectal adenomas using the novel magnifying colonoscope with BLI and quantitatively analyzed the changes in hemodynamic parameters.

METHODS

From October 2019 to January 2020, 11 patients were screened for colon adenomas with the novel high-resolution magnification endoscope with BLI. Video images were recorded and processed with Adobe Premiere, Adobe Photoshop and Image-pro Plus software. Four microcirculation parameters: Microcirculation vessel density (MVD), mean vessel width (MVW) with width standard deviation (WSD), and blood flow velocity (BFV), were calculated for adenomas and the surrounding normal mucosa.

RESULTS

A total of 16 adenomas were identified. Compared with the normal surrounding mucosa, the superficial vessel density in the adenomas was decreased (MVD: 0.95 ± 0.18 vs 1.17 ± 0.28 μm/μm2, P < 0.05). MVW (5.11 ± 1.19 vs 4.16 ± 0.76 μm, P < 0.05) and WSD (11.94 ± 3.44 vs 9.04 ± 3.74, P < 0.05) were both increased. BFV slowed in the adenomas (709.74 ± 213.28 vs 1256.51 ± 383.31 μm/s, P < 0.05).

CONCLUSION

The novel high-resolution magnification endoscope with BLI can be used for in vivo study of adenoma superficial microcirculation. Superficial vessel density was decreased, more irregular, with slower blood flow.

Intravital Microscopy Evidence That Methylene Blue Should Be a Vasopressor-Sparing Agent in Sepsis Vasoplegia

Microvasculature failure is expected in sepsis and at higher amine concentrations. Therefore, special attention focused individually on microcirculation is needed. Here, we present that methylene blue can prevent leukocytes from adhering to the endothelium in a rat model of lipopolysaccharide-induced endotoxemia. As hypothesis evidence, an intravital microscopy image is presented.

Monitoring of Perioperative Microcirculation Dysfunction by Near-Infrared Spectroscopy for Neurological Deterioration and Prognosis of Aneurysmal Subarachnoid Hemorrhage: An Observational, Longitudinal Cohort Study

INTRODUCTION

No evidence has established a direct causal relationship between early microcirculation disturbance after aneurysmal subarachnoid hemorrhage (aSAH) and neurological function prognosis, which is the key pathophysiological mechanism of early brain injury (EBI) in patients with aSAH.

METHODS

A total of 252 patients with aSAH were enrolled in the Neurosurgical Intensive Care Unit of Southwest Hospital between January 2020 and December 2022 and divided into the no neurological deterioration, early neurological deterioration, and delayed neurological deterioration groups. Indicators of microcirculation disorders in EBI included regional cerebral oxygen saturation (rSO2) measured by near-infrared spectroscopy (NIRS), brain oxygen monitoring, and other clinical parameters for evaluating neurological function and determining the prognosis of patients with aSAH.

RESULTS

Our data suggest that the rSO2 is generally lower in patients who develop neurological deterioration than in those who do not and that there is at least one time point in the population of patients who develop neurological deterioration where left and right cerebral hemisphere differences can be significantly monitored by NIRS. An unordered multiple-classification logistic regression model was constructed, and the results revealed that multiple factors were effective predictors of early neurological deterioration: reoperation, history of brain surgery, World Federation of Neurosurgical Societies (WFNS) grade 4-5, Fisher grade 3-4, SAFIRE grade 3-5, abnormal serum sodium and potassium levels, and reduced rSO2 during the perioperative period. However, for delayed neurological deterioration in patients with aSAH, only a history of brain surgery and perioperative RBC count were predictive indicators.

CONCLUSIONS

The rSO2 concentration in patients with neurological deterioration is generally lower than that in patients without neurological deterioration, and at least one time point in the population with neurological deterioration can be significantly monitored via NIRS. However, further studies are needed to determine the role of microcirculation and other predictive factors in the neurocritical management of EBI after aSAH, as these factors can reduce the incidence of adverse outcomes and mortality during hospitalization.

Physiology and functional significance of the coronary microcirculation: An overview of its implications in health and disease

Ischemic, Coronary Heart Disease (CHD) is a leading cause of morbidity and death worldwide.

Intracoronary Thrombolysis in ST-Segment Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention: an Updated Meta-analysis of Randomized Controlled Trials

BACKGROUND

Primary percutaneous coronary intervention (PPCI) is the standard reperfusion treatment in ST-segment elevation myocardial infarction (STEMI). Intracoronary thrombolysis (ICT) may reduce thrombotic burden in the infarct-related artery, which is often responsible for microvascular obstruction and no-reflow.

METHODS

We conducted, according to the PRISMA statement, the largest meta-analysis to date of ICT as adjuvant therapy to PPCI. All relevant studies were identified by searching the PubMed, Scopus, Cochrane Library, and Web of Science.

RESULTS

Thirteen randomized controlled trials (RCTs) involving a total of 1876 patients were included. Compared to the control group, STEMI ICT-treated patients had fewer major adverse cardiac events (MACE) (OR 0.65, 95% CI, 0.48-0.86, P = 0.003) and an improved 6-month left ventricular ejection fraction (MD 3.78, 95% CI, 1.53-6.02, P = 0.0010). Indices of enhanced myocardial microcirculation were better with ICT (Post-PCI corrected thrombolysis in myocardial infarction (TIMI) frame count (MD - 3.57; 95% CI, - 5.00 to - 2.14, P < 0.00001); myocardial blush grade (MBG) 2/3 (OR 1.76; 95% CI, 1.16-2.69, P = 0.008), and complete ST-segment resolution (OR 1.97; 95% CI, 1.33-2.91, P = 0.0007)). The odds for major bleeding were comparable between the 2 groups (OR 1.27; 95% CI, 0.61-2.63, P = 0.53).

CONCLUSIONS

The present meta-analysis suggests that ICT was associated with improved MACE and myocardial microcirculation in STEMI patients undergoing PPCI, without significant increase in major bleeding. However, these findings necessitate confirmation in a contemporary large RCT.

The influence of triglyceride and low-density-lipoprotein target levels on microcirculation: Is there a difference?

Background and aims

This study aimed to validate the role of high low-density lipoprotein cholesterol [LDL-C] and triglyceride [TG] treatment target levels on the microcirculation in a very high and high cardiovascular risk group.

Methods

119 patients with high or very high cardiovascular [CV] risk were included. We have registered the main co-morbidities, smoking habits, body mass index [BMI] and the lipid lowering medication. Hematocrit, whole blood viscosity [WBV] and plasma viscosity [PV], red blood cell [RBC] aggregation and deformability and fibrinogen, total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], LDL-C and TG levels were determined.

Results

The investigation found significantly higher PV values in patients with non-target LDL-C, associated with higher fibrinogen level. Non-target TG was related to deteriorated microcirculatory parameters, as significantly higher RBC aggregation, lower RBC deformability, and higher WBV and PV. The main microcirculatory benefit in diabetes could be gained from target level of TG, in chronic coronary syndrome [CCS] patients it is more advantageous to reach both LDL-C and TG target.

Conclusion

The results could highlight, that TG should play a role in failing microcirculation and cause potentially life-threatening complications, which would worsen the survival and quality of life of high or very high risk CV patients.

Optimization of cardiopulmonary bypass prime fluid to preserve microcirculatory perfusion during on-pump coronary artery bypass graft surgery: PRIME study protocol for a double-blind randomized trial

BACKGROUND

Acute microcirculatory perfusion disturbances and organ edema are important factors leading to organ dysfunction during cardiac surgery with cardiopulmonary bypass (CPB). Priming of the CPB system with crystalloid or colloid fluids, which inevitably leads to hemodilution, could contribute to this effect. However, there is yet no optimal evidence-based strategy for this type of priming. Hence, we will investigate different priming strategies to reduce hemodilution and preserve microcirculatory perfusion.

METHODS

The PRIME study is a single-center double-blind randomized trial. Patients undergoing elective coronary artery bypass graft surgery with CPB will be randomized into three groups of prime fluid strategy: (1) gelofusine with crystalloid, (2) albumin with crystalloid, or (3) crystalloid and retrograde autologous priming. We aim to include 30 patients, 10 patients in each arm. The primary outcome is the change in microcirculatory perfusion. Secondary outcomes include colloid oncotic pressure; albumin; hematocrit; electrolytes; fluid balance and requirements; transfusion rates; and endothelial-, glycocalyx-, inflammatory- and renal injury markers. Sublingual microcirculatory perfusion will be measured using non-invasive sidestream dark field video microscopy. Microcirculatory and blood measurements will be performed at five consecutive time points during surgery up to 24 h after admission to the intensive care unit.

DISCUSSION

PRIME is the first study to assess the effect of different prime fluid strategies on microcirculatory perfusion in cardiac surgery with CPB. If the results suggest that a specific crystalloid or colloid prime fluid strategy better preserves microcirculatory perfusion during on-pump cardiac surgery, the current study may help to find the optimal pump priming in cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05647057. Registered on 04/25/2023.

CLINICALTRIALS

gov PRS: Record Summary NCT05647057, all items can be found in the protocol.

The therapeutic effect of Picroside II in renal ischemia-reperfusion induced acute kidney injury: An experimental study

The microcirculation hemodynamics change and inflammatory response are the two main pathophysiological mechanisms of renal ischemia-reperfusion injury (IRI) induced acute kidney injury (AKI). The treatment of microcirculation hemodynamics and inflammatory response can effectively alleviate renal injury and correct renal function. Picroside II (P II) has a wide range of pharmacological effects. Still, there are few studies on protecting IRI-AKI, and whether P II can improve renal microcirculation perfusion is still being determined. This study aims to explore the protective effect of P II on IRI-AKI and evaluate its ability to enhance renal microcirculation perfusion. In this study, a bilateral renal IRI-AKI model in mice was established, and the changes in renal microcirculation and inflammatory response were quantitatively evaluated before and after P II intervention by contrast-enhanced ultrasound (CEUS). At the same time, serum and tissue markers were measured to assess the changes in renal function. The results showed that after P II intervention, the levels of serum creatinine (Scr), blood urea nitrogen (BUN), serum cystatin C (Cys-C), kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), and superoxide dismutase (SOD), as well as the time-to-peak (TTP), peak intensity (PI) and area under the curve (AUC), and the normalized intensity difference (NID) were all alleviated. In conclusion, P II can improve renal microcirculation perfusion changes caused by IRI-AKI, reduce inflammatory reactions during AKI, and enhance renal antioxidant stress capacity. P II may be a new and promising drug for treating IRI-AKI.

Capillary refill time assessment after fluid challenge in patients on venoarterial extracorporeal membrane oxygenation: A retrospective study

BACKGROUND

Monitoring fluid therapy is challenging in patients assisted with Veno-arterial ECMO. The aim of our study was to evaluate the usefulness of capillary refill time to assess the response to fluid challenge in patients assisted with VA-ECMO.

METHODS

Retrospective monocentric study in a cardiac surgery ICU. We assess fluid responsiveness after a fluid challenge in patients on VA-ECMO. We recorded capillary refill time before and after fluid challenge and the evolution of global hemodynamic parameters.

RESULTS

A total of 27 patients were included. The main indications for VA-ECMO were post-cardiotomy cardiogenic shock (44%). Thirteen patients (42%) were responders and 14 non-responders (58%). In the responder group, the index CRT decreased significantly (1.7 [1.5; 2.1] vs. 1.2 [1; 1.3] s; p = 0.01), whereas it remained stable in the non-responder group (1.4 [1.1; 2.5] vs. 1.6 [0.9; 1.9] s; p = 0.22). Diagnosis performance of CRT variation to assess response after fluid challenge shows an AUC of 0.68 (p = 0.10) with a sensitivity of 79% [95% CI, 52-92] and a specificity of 69% [95% CI, 42-87], with a threshold at 23%.

CONCLUSION

In patients treated with VA-ECMO index capillary refill time is a reliable tool to assesses fluid responsiveness.

SPECIALTY

Critical care, Cardiac surgery, ECMO.

Assessment of microcirculatory alteration by a vascular occlusion test using near-infrared spectroscopy in pediatric cardiac surgery: effect of cardiopulmonary bypass

OBJECTIVES

Cardiopulmonary bypass cause microcirculatory alterations. Near infrared spectroscopic measurement of tissue oxygen saturation and vascular occlusion test are novel technologies for assessing the microcirculatory function of peripheral tissue specifically in patients undergoing cardiac surgery with cardiopulmonary bypass.Our study aimed to evaluate dynamic microcirculatory function using the vascular occlusion testing during cardiac surgery in pediatric patients.

METHODS

120 pediatric patients were scheduled. Children had continuous regional oxygen saturation monitoring using near infrared spectroscopy and vascular occlusion test. Vascular occlusion test was performed five times; before induction (T1), after induction (T2), then during cardiopulmonary bypass with full flow (T3), after the termination of CPB (T4) and after sternum closure (T5).

RESULTS

Basal value was the lowest at T3 and this value was significantly different among measurements (p < 0,01).Values for maximum and minimum tissue oxygen saturation were the lowest at T3 (83,4 and 52,9%).The occlusion slope varied significantly among measurements (p < 0,01).Reperfusion slopes were significantly different among measurements (p < 0,01) with a further progressive decrease in reperfusion slope with duration of cardiopulmonary bypass.

CONCLUSION

Microcirculatory function can assessed using VOT with forearm Near-infrared spectroscopy derived variables during cardiopulmonary bypass in pediatric cardiac surgery. Noninvasive assessment of microcirculatory perfusion during cardiopulmonary bypass can further help evaluate and improve circulatory support techniques.

TRIAL REGISTRATION

The research Project was registered at ClinicalTrials.gov (NCT06191913).

The conducted vascular response as a mediator of hypercapnic cerebrovascular reactivity: A modelling study

It is well established that the cerebral blood flow (CBF) shows exquisite sensitivity to changes in the arterial blood partial pressure of CO2 ( [Formula: see text] ), which is reflected by an index termed cerebrovascular reactivity. In response to elevations in [Formula: see text] (hypercapnia), the vessels of the cerebral microvasculature dilate, thereby decreasing the vascular resistance and increasing CBF. Due to the challenges of access, scale and complexity encountered when studying the microvasculature, however, the mechanisms behind cerebrovascular reactivity are not fully understood. Experiments have previously established that the cholinergic release of the Acetylcholine (ACh) neurotransmitter in the cortex is a prerequisite for the hypercapnic response. It is also known that ACh functions as an endothelial-dependent agonist, in which the local administration of ACh elicits local hyperpolarization in the vascular wall; this hyperpolarization signal is then propagated upstream the vascular network through the endothelial layer and is coupled to a vasodilatory response in the vascular smooth muscle (VSM) layer in what is known as the conducted vascular response (CVR). Finally, experimental data indicate that the hypercapnic response is more strongly correlated with the CO2 levels in the tissue than in the arterioles. Accordingly, we hypothesize that the CVR, evoked by increases in local tissue CO2 levels and a subsequent local release of ACh, is responsible for the CBF increase observed in response to elevations in [Formula: see text] . By constructing physiologically grounded dynamic models of CBF and control in the cerebral vasculature, ones that integrate the available knowledge and experimental data, we build a new model of the series of signalling events and pathways underpinning the hypercapnic response, and use the model to provide compelling evidence that corroborates the aforementioned hypothesis. If the CVR indeed acts as a mediator of the hypercapnic response, the proposed mechanism would provide an important addition to our understanding of the repertoire of metabolic feedback mechanisms possessed by the brain and would motivate further in-vivo investigation. We also model the interaction of the hypercapnic response with dynamic cerebral autoregulation (dCA), the collection of mechanisms that the brain possesses to maintain near constant CBF despite perturbations in pressure, and show how the dCA mechanisms, which otherwise tend to be overlooked when analysing experimental results of cerebrovascular reactivity, could play a significant role in shaping the CBF response to elevations in [Formula: see text] . Such in-silico models can be used in tandem with in-vivo experiments to expand our understanding of cerebrovascular diseases, which continue to be among the leading causes of morbidity and mortality in humans.

Goal-directed colloid versus crystalloid therapy and microcirculatory blood flow following ischemia/reperfusion

OBJECTIVE

Ischemia/reperfusion can impair microcirculatory blood flow. It remains unknown whether colloids are superior to crystalloids for restoration of microcirculatory blood flow during ischemia/reperfusion injury. We tested the hypothesis that goal-directed colloid - compared to crystalloid - therapy improves small intestinal, renal, and hepatic microcirculatory blood flow in pigs with ischemia/reperfusion injury.

METHODS

This was a randomized trial in 32 pigs. We induced ischemia/reperfusion by supra-celiac aortic-cross-clamping. Pigs were randomized to receive either goal-directed isooncotic hydroxyethyl-starch colloid or balanced isotonic crystalloid therapy. Microcirculatory blood flow was measured using Laser-Speckle-Contrast-Imaging. The primary outcome was small intestinal, renal, and hepatic microcirculatory blood flow 4.5 h after ischemia/reperfusion. Secondary outcomes included small intestinal, renal, and hepatic histopathological damage, macrohemodynamic and metabolic variables, as well as specific biomarkers of tissue injury, renal, and hepatic function and injury, and endothelial barrier function.

RESULTS

Small intestinal microcirculatory blood flow was higher in pigs assigned to isooncotic hydroxyethyl-starch colloid therapy than in pigs assigned to balanced isotonic crystalloid therapy (768.7 (677.2-860.1) vs. 595.6 (496.3-694.8) arbitrary units, p = .007). There were no important differences in renal (509.7 (427.2-592.1) vs. 442.1 (361.2-523.0) arbitrary units, p = .286) and hepatic (604.7 (507.7-701.8) vs. 548.7 (444.0-653.3) arbitrary units, p = .376) microcirculatory blood flow between groups. Pigs assigned to colloid - compared to crystalloid - therapy also had less small intestinal, but not renal and hepatic, histopathological damage.

CONCLUSIONS

Goal-directed isooncotic hydroxyethyl-starch colloid - compared to balanced isotonic crystalloid - therapy improved small intestinal, but not renal and hepatic, microcirculatory blood flow in pigs with ischemia/reperfusion injury. Whether colloid therapy improves small intestinal microcirculatory blood flow in patients with ischemia/reperfusion needs to be investigated in clinical trials.

Changes in renal microcirculation in patients with nephrotic and nephritic syndrome: The role of resistive index

BACKGROUND

Renal Resistive Index (RRI) is an important and non-invasive parameter of renal damage and it is associated with abnormal microcirculation or to a parenchymal injury. The aim of our study was to compare the RRI in a cohort of patients with renal diseases categorized in three groups: nephrotic syndrome (NS), acute nephritic syndrome (ANS) and patients with urinary abnormalities (UA).

METHODS

Four hundred eighty-two patients with median age of 48 years (IQR 34-62) with indications for kidney disease were included in the study. Biochemical analyses, clinical assessment with detection of NS, ANS and UA and comorbidities were reported. Renal Doppler ultrasound with RRI was evaluated in all patients at the time of enrolment.

RESULTS

NS was present in 81 (16.8 %) patients while ANS in 81 (16.8 %) and UA in 228 (47.3 %) patients. Patients with ANS showed significant higher RRI compared to both patients with NS [0.71 (IQR 0.67-0.78) vs 0.68 (0.63-0.73), p < 0.001] and UA [0.71 (0.67-0.78) vs 0.65 (0.61-0.71), p < 0.001]; RRI was higher in NS patients than in patients with UA [0.68 (0.63-0.73) vs 0.65 (0.61-0.71), p < 0.001]. Patients with ANS had significantly lower median estimated glomerular filtration rate (eGFR) compared respectively to NS and UA patients [19.7 ml/min vs 54.8 ml/min and vs 72.3 ml/min, p < 0.001], while renal length was significantly higher in patients with NS compared to both patients with ANS and UA [111.88 mm vs 101.98 mm and vs 106.15, p < 0.001]. Patients with ANS had more frequently hematuria and RRI ≥ 0.70 (p < 0.001) compared to both patients with NS and patients with UA. The multiple regression analysis, weighted for age, showed that RRI inversely correlates with eGFR (β coefficient = -0.430, p < 0.001).

CONCLUSIONS

Higher and pathological RRI were found in ANS than NS and UA. Renal resistive index in ANS reflects changes in intrarenal perfusion and microvascular dysfunction related to disease characteristics.

Relationship between the structure and microcirculation of the optic disc region and myopic traction maculopathy in highly myopic eyes

PURPOSE

To explore the characteristics and influencing factors structural and microcirculatory of optic disc and peripapillary tissue in eyes with myopia traction maculopathy (MTM).

METHODS

There were 100 eyes from 77 patients in this study. We used 1:1 matching axial length in myopic eyes. Patients were divided into two groups according to the presence or absence of MTM. Fundus structure parameters were obtained by swept source optical coherence tomography (SS-OCT), and the optic disc microcirculation parameters were obtained by OCT angiography (OCTA).

RESULTS

MTM group were older (P = 0.001) and had poorer Best-corrected Visual Acuity (BCVA) (P = 0.011), the optic disc-fovea distance (DFD) was longer (P < 0.019), optic disc tilt was greater (P < 0.001), area of peripapillary atrophy (PPA) was larger (P < 0.001), and PPA/optical disc area (ONH) was higher (P < 0.001). The peripapillary scleral thickness (PST) was lower in the MTM group (P < 0.001). The mean peripapillary choroidal thickness (PCT) (P < 0.001) and PCT in the 10 orientations were significantly lower in the MTM group than in the NMTM group (all P < 0.01). Vascular density in the nasosuperior (NS) region of the optic disc was significantly lower in the MTM group (P = 0.037). The generalized estimating equation suggested that PPA area (P = 0.028), mean PCT (P = 0.008), superior PCT (P = 0.027), inferonasal PCT (P = 0.040), temporoinferior PCT (P = 0.013), and PST (P = 0.046) correlated with MTM. Age, axial length, optic disc tilt, PPA area, mean PCT, and optic disc central zone (0-2 mm) vascular density (all P < 0.05) were significantly correlated with PST.

CONCLUSIONS

The enlarged PPA area and thinner PCT and PST in eyes with MTM are more significant. Lower PST in high myopia was related to abnormalities of PCT and microcirculation.

TRIAL REGISTRATION

Clinical Trial Registration number: ChiCTR2100046590.

Preoperative endothelial dysfunction for the prediction of acute kidney injury after cardiac surgery using cardiopulmonary bypass: a pilot study based on a second analysis of the MONS study

BACKGROUND

Up to 42% of patients develop acute kidney injury (AKI) after cardiac surgery. The aim of this study was to describe the relationship between preoperative microcirculatory function and postoperative AKI after cardiac surgery using cardiopulmonary bypass (CPB).

METHODS

The prospective observational cohort MONS enrolled 60 patients scheduled for valvular (n = 30, 50%) or coronary (n = 30, 50%) surgery using CPB. Preoperative microcirculation was assessed during preoperative consultation from January 2019 to April 2019 at the University Hospital of Angers, France, using endothelium-dependent and endothelium-independent reactivity tests on the forearm (iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), respectively). Skin blood flow was measured by laser speckle contrast imaging. The primary endpoint was the occurrence of AKI according to the KDIGO classification during the hospital stay.

RESULTS

Forty-three (71.7%) patients developed AKI during the in-hospital follow-up, and 15 (25%) were classified as KDIGO stage 1, 20 (33%) KDIGO stage 2, and 8 (13%) KDIGO stage 3. Regarding preoperative microcirculation, a higher peak amplitude of vasodilation in response to iontophoresis of ACh was found in patients with postoperative occurrence of AKI (35 [20-49] vs 23 [9-44] LSPU, p = 0.04). Iontophoresis of SNP was not significantly different according to AKI occurrence (34 [22-49] vs 36 [20-50] LSPU, p = 0.95). In a multivariable model, the preoperative peak amplitude at iontophoresis of ACh was independently associated with postoperative AKI (OR 1.045 [1.001-1.092], p = 0.045).

CONCLUSIONS

The preoperative peak amplitude of endothelium-dependent vasodilation is independently associated with the postoperative occurrence of AKI.

TRIAL REGISTRATION

Clinical-Trials.gov, NCT03631797. Registered 15 August 2018, https://clinicaltrials.gov/ct2/show/NCT03631797.

Morphological characteristics of the foveal avascular zone in pathological myopia and its relationship with macular structure and microcirculation

PURPOSE

To explore the characteristics of macular structure, microcirculation, and foveal avascular zone (FAZ) morphology in pathological myopia and to research the associations between these factors and pathological myopia.

METHODS

This is a cross-sectional study. The study included 103 eyes with non-high myopia and 206 eyes with high myopia (139 with simple high myopia and 67 with pathological myopia). Macular structural and microcirculation parameters were determined using optical coherence tomography angiography (OCTA). The FAZ morphological parameters were measured manually using Image J software. Correlations between pathological myopia and various factors were analyzed.

RESULTS

Patients with pathological myopia had a thinner retinal thickness (RT) and choroidal thickness (CT) and a lower retinal superficial vascular density (SVD), retinal deep vascular complex density (DVD), choriocapillaris perfusion area (CCPA), and choroidal vascularity index (CVI) (all P < 0.05). Patients with pathological myopia had a larger FAZ area, perimeter, major axis, minor axis, acircularity index (AI), and lower circularity index (CI) (all P < 0.01). The axial length (AL), the major axis of the superficial FAZ, CI, and AI were significantly correlated with myopia severity (all P < 0.05).

CONCLUSIONS

Patients with pathological myopia exhibited worse macular microcirculation and thinner macular retina and choroid. The FAZ in pathological myopia was larger and more irregular. The AL, CI, and AI were significantly associated with myopia severity. Thus, CI and AI might serve as new indicators for monitoring the progression of myopia. Further investigations should be performed.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: ChiCTR2100046590.

Acute neutrophilic vasculitis (leukocytoclasia) in 36 COVID-19 autopsy brains

BACKGROUND

Hypercytokinemia, the renin-angiotensin system, hypoxia, immune dysregulation, and vasculopathy with evidence of immune-related damage are implicated in brain morbidity in COVID-19 along with a wide variety of genomic and environmental influences. There is relatively little evidence of direct SARS-CoV-2 brain infection in COVID-19 patients.

METHODS

Brain histopathology of 36 consecutive autopsies of patients who were RT-PCR positive for SARS-CoV-2 was studied along with findings from contemporary and pre-pandemic historical control groups. Immunostaining for serum and blood cell proteins and for complement components was employed. Microcirculatory wall complement deposition in the COVID-19 cohort was compared to historical control cases. Comparisons also included other relevant clinicopathological and microcirculatory findings in the COVID-19 cohort and control groups.

RESULTS

The COVID-19 cohort and both the contemporary and historical control groups had the same rate of hypertension, diabetes mellitus, and obesity. The COVID-19 cohort had varying amounts of acute neutrophilic vasculitis with leukocytoclasia in the microcirculation of the brain in all cases. Prominent vascular neutrophilic transmural migration was found in several cases and 25 cases had acute perivasculitis. Paravascular microhemorrhages and petechial hemorrhages (small brain parenchymal hemorrhages) had a slight tendency to be more numerous in cohort cases that displayed less acute neutrophilic vasculitis. Tissue burden of acute neutrophilic vasculitis with leukocytoclasia was the same in control cases as a group, while it was significantly higher in COVID-19 cases. Both the tissue burden of acute neutrophilic vasculitis and the activation of complement components, including membrane attack complex, were significantly higher in microcirculatory channels in COVID-19 cohort brains than in historical controls.

CONCLUSIONS

Acute neutrophilic vasculitis with leukocytoclasia, acute perivasculitis, and associated paravascular blood extravasation into brain parenchyma constitute the first phase of an immune-related, acute small-vessel inflammatory condition often termed type 3 hypersensitivity vasculitis or leukocytoclastic vasculitis. There is a higher tissue burden of acute neutrophilic vasculitis and an increased level of activated complement components in microcirculatory walls in COVID-19 cases than in pre-pandemic control cases. These findings are consistent with a more extensive small-vessel immune-related vasculitis in COVID-19 cases than in control cases. The pathway(s) and mechanism for these findings are speculative.

Potential of acetaminophen on the sublingual microcirculation and peripheral tissue perfusion of febrile septic patients: prospective observational study

BACKGROUND

Acetaminophen (ACT) has been studied in septic patients with detectable plasmatic levels of cell-free hemoglobin (Hb), where it demonstrated to inhibit the hemoprotein-mediated lipid peroxidation and oxidative injury, with a potential of beneficial effect on the endothelium. On the basis of this background, the aim of this study was to evaluate the sublingual microcirculation and the peripheral tissue perfusion before-and-after administration of ACT on clinical judgment in a cohort of febrile septic and septic shock patients.

METHODS

Prospective observational study. 50 adult septic and septic shocks treated with ACT for pyrexia, where the sublingual microcirculation and the peripheral tissue perfusion with Near Infrared Spectroscopy (NIRS) and vascular occlusion test (VOT) were evaluated before ACT (t0), after 30 min (t1) and after 2 h (t2). Cell-free Hb and the markers of oxidative stress and endothelial damage were measured at t0 and t2.

RESULTS

The study showed a significant increase of the density of the perfused small and total vessels of the sublingual microcirculation 30 min after the infusion of ACT; it also showed an increase of the Microvascular Flow Index (MFI) and a decrease in the heterogeneity of the flow. At a peripheral muscular level, we found an acceleration in the reperfusion curve after VOT at t1, expression of a higher reactivity of the microvasculature.

CONCLUSIONS

ACT infusion did not show a clear correlation with cell-free Hb; however, it exhibited protective effect toward the microcirculation that was evident in particular in septic patients. This correlation merits further exploration.

Association between cardiovascular risk profile and impaired microvascular function in a Swedish middle-aged cohort (the SCAPIS study)

AIM

The aim was to investigate the relationship between microvascular function, cardiovascular risk profile, and subclinical atherosclerotic burden.

METHODS

The study enrolled 3809 individuals, 50-65 years old, participating in the population-based observational cross-sectional Swedish CArdioPulmonary bioImage Study (SCAPIS). Microvascular function was assessed in forearm skin using an arterial occlusion and release protocol determining peak blood oxygen saturation (OxyP). Cardiovascular risk was calculated using the updated Systematic Coronary Risk Evaluation (SCORE2; 10-year risk of fatal and non-fatal CVD events). OxyP was compared with Coronary Artery Calcification Score (CACS) and to plaques in the carotid arteries.

RESULTS

Individuals with OxyP values in the lowest quartile (Q1; impaired microvascular function), had a mean SCORE2 of 5.8% compared to 3.8% in those with the highest values of OxyP (Q4), a relative risk increase of 53%. The risk of having a SCORE2 > 10% was 5 times higher for those in Q1 (OR: 4.96 95% CI: 2.76-8.93) vs. Q4 when adjusting for BMI and hsCRP. OxyP was lower in individuals with CACS > 0, and in those with both carotid plaques and CACS >0, =compared with individuals without subclinical atherosclerotic burdens (87.5 ± 5.6% and 86.9 ± 6.0%, vs 88.6 ± 5.8%, p < 0.01).

CONCLUSION

In a population without cardiovascular disease or diabetes mellitus, impaired microvascular function is associated with cardiovascular risk profiles such as higher SCORE2 risk and CACS. We suggest that OxyP may serve as a microcirculatory functional marker of subclinical atherosclerosis and CVD risk, that is not detected by structural assessments.

Shaping the Neurovascular Unit Exploiting Human Brain Organoids

Brain organoids, three-dimensional cell structures derived from pluripotent stem cells, closely mimic key aspects of the human brain in vitro, providing a powerful tool for studying neurodevelopment and disease. The neuroectodermal induction protocol employed for brain organoid generation primarily gives rise to the neural cellular component but lacks the vital vascular system, which is crucial for the brain functions by regulating differentiation, migration, and circuit formation, as well as delivering oxygen and nutrients. Many neurological diseases are caused by dysfunctions of cerebral microcirculation, making vascularization of human brain organoids an important tool for pathogenetic and translational research. Experimentally, the creation of vascularized brain organoids has primarily focused on the fusion of vascular and brain organoids, on organoid transplantation in vivo, and on the use of microfluidic devices to replicate the intricate microenvironment of the human brain in vitro. This review summarizes these efforts and highlights the importance of studying the neurovascular unit in a forward-looking perspective of leveraging their use for understanding and treating neurological disorders.

Treatment of patients with multiple organ dysfunction syndrome (MODS) with an electromagnetic field coupled to biorhythmically defined impulse configuration: the MicrocircMODS study

BACKGROUND

To potentially improve impaired vasomotion of patients with multiple organ dysfunction syndrome (MODS), we tested whether an electromagnetic field of low flux density coupled with a biorhythmically defined impulse configuration (Physical Vascular Therapy BEMER®, PVT), in addition to standard care, is safe and feasible and might improve disturbed microcirculatory blood flow and thereby improve global haemodynamics.

METHODS

In a prospective, monocentric, one-arm pilot study, 10 MODS patients (APACHE II score 20-35) were included. Patients were treated, in addition to standard care, for 4 days with PVT (3 treatment periods of 8 min each day; day 1: field intensity 10.5 μT; day 2:14 μT, day 3:17.5 μT; day 4:21.0 μT). Primary endpoint was the effect of PVT on sublingual microcirculatory perfusion, documented by microvascular flow index (MFI). Patient safety, adverse events, and outcomes were documented.

RESULTS

An increase in MFI by approximately 25% paralleled 4-day PVT, with the increase starting immediately after the first PVT and lasting over the total 4-day treatment period. Concerning global haemodynamics (secondary endpoints), halving vasopressor use within 24 h, and haemodynamic stabilisation paralleled 4-day PVT with an increase in cardiac index, stroke volume index, and cardiac power index by 30%-50%. No adverse events (AEs) or serious adverse events (SAEs) were classified as causally related to the medical product (PVT) or study. Three patients died within 28 days and one patient between 28 and 180 days.

CONCLUSION

PVT treatment was feasible and safe and could be performed without obstruction of standard patient care. An increase in microcirculatory blood flow, a rapid reduction in vasopressor use, and an improvement in global haemodynamics paralleled PVT treatment. Findings of this pilot study allowed forming a concept for a randomized trial for further proof.

Microvascular status in juvenile Sjögren's disease: the first nailfold videocapillaroscopy investigation

INTRODUCTION

Juvenile Sjögren's disease (jSjD) is a rare autoimmune disease characterized by exocrine gland involvement and systemic manifestations, including small vessel vasculitis and Raynaud's phenomenon (RP). We aimed to investigate the microvascular status in jSjD patients by nailfold videocapillaroscopy (NVC) and the potential correlations with clinical and serological features.

METHODS

Clinical data from thirteen consecutive jSjD patients (11 females and 2 males), with a mean age of 16 ± 4 years, diagnosed before 16 years of age (mean age at diagnosis 12 ± 3) according to the 2016 American College of Rheumatology/EULAR criteria for adult SjD, were collected including age- and sex-matched healthy controls (HCs). Clinical, laboratory, and instrumental data were collected, together with NVC examination. Non-specific and specific NVC parameters were investigated, such as capillary density, capillary dilations, giant capillaries, microhaemorrhages and abnormal shapes. Associations between NVC findings and clinical/serological features were explored and analysed using parametrical and non-parametrical tests.

RESULTS

Capillary density reduction correlated significantly with articular involvement (arthralgias) (p = 0.024). Microhaemorrhages correlated with lower C3 levels (p = 0.034). No specific NVC pattern for jSjD was identified, whereas abnormal capillary shapes were significantly higher in jSjD patients than HCs (p = 0.005). NVC abnormalities were not associated with SjD-specific instrumental tests (biopsy, imaging, Schirmer's test). RP was present in 8% of jSjD patients.

CONCLUSIONS

The reduction of capillary density, as well as microhaemorrhages at NVC analysis, are significantly associated with some clinical aspects like articular involvement and serum biomarkers (C3 reduction). The NVC is suggested as safe and further analysis in jSjD patients.

Evaluation of retinal structural and functional changes after silicone oil removal in patients with rhegmatogenous retinal detachment: a retrospective study

BACKGROUND

To evaluate retinal structural and functional changes after silicone oil (SO) removal in eyes with macula-off rhegmatogenous retinal detachment (RRD).

METHODS

Best-corrected visual acuity (BCVA) testing, microperimetry, and optical coherence tomography angiography were performed in 48 eyes with macula-off RRD before and 3 months after SO removal. The values of healthy contralateral eyes were used as control data. Correlations between retinal vessel density (VD), retinal nerve fiber layer thickness (RNFLT), the interval between retinal detachment and surgery, the duration of SO tamponade, the follow-up time after SO removal, and visual function were analyzed.

RESULTS

Significant increases in 2˚ fixation rate (FR), 4˚ FR, 2˚ mean retinal sensitivity (MRS), 6˚ MRS, parafoveal superficial capillary plexus VD and RNFLT were observed after SO removal (all P < 0.05). The increase of 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade and the follow-up time after SO removal respectively (all P < 0.05). The last 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade, the interval between retinal detachment and surgery, and the follow-up time after SO removal (all P < 0.01). The last FR in RRD eyes was close to that of contralateral eyes (P > 0.05).

CONCLUSION

Retinal structure and function improved to different degrees after SO removal. Fixation stability and retinal sensitivity increased more than BCVA postoperatively. Retinal sensitivity, which was affected by the interval between retinal detachment and surgery and the duration of SO tamponade, gradually recovered after SO removal.

Effects of acute phosphodiesterase type 5 inhibition on skeletal muscle interstitial PO2 during contractions and recovery

The oxygen partial pressure within the interstitial space (PO2is; mmHg) provides the driving force for oxygen diffusion into the myocyte thereby supporting oxidative phosphorylation. We tested the hypothesis that potentiation of the nitric oxide pathway with sildenafil (phosphodiesterase type 5 inhibitor) would enhance PO2is during muscle metabolic transitions, thereby slowing PO2is on- and accelerating PO2is off-kinetics. The rat spinotrapezius muscle (n = 17) was exposed for PO2is measurements via phosphorescence quenching under control (CON), low-dose sildenafil (1 mg/kg i.a., SIL1) and high-dose sildenafil (7 mg/kg i.a., SIL7). Data were collected at rest and during submaximal twitch contractions (1 Hz, 4-6 V, 3 min) and recovery (3 min). Mean arterial blood pressure (MAP; mmHg) was reduced with both SIL1 (pre:132 ± 5; post:99 ± 5) and SIL7 (pre:111 ± 6; post:99 ± 4) (p < 0.05). SIL7 elevated resting PO2is (18.4 ± 1.1) relative to both CON (15.7 ± 0.7) and SIL1 (15.2 ± 0.7) (p < 0.05). In addition, SIL7 increased end-recovery PO2is (17.7 ± 1.6) compared to CON (12.8 ± 0.9) and SIL1 (13.4 ± 0.8) (p < 0.05). The overall PO2is response during recovery (i.e., area under the PO2is curve) was greater in SIL7 (4107 ± 444) compared to CON (3493 ± 222) and SIL1 (3114 ± 205 mmHg s) (p < 0.05). Contrary to our hypothesis, there was no impact of acute SIL (1 or 7 mg/kg) on the speed of the PO2is response during contractions or recovery (p > 0.05). However, sildenafil lowered MAP and improved skeletal muscle interstitial oxygenation in healthy rats. Specifically, SIL7 enhanced PO2is at rest and during recovery from submaximal muscle contractions. Potentiation of the nitric oxide pathway with sildenafil enhances microvascular blood-myocyte O2 transport and is expected to improve repeated bouts of contractile activity.

Time-Lapse Observation of Cell Dynamics During Angiogenesis Using the Rat Mesentery Culture Model

The ability to track cells and their interactions with other cells during physiological processes offers a powerful tool for scientific discovery. An ex vivo model that enables real-time investigation of cell migration during angiogenesis in adult microvascular networks would enable observation of endothelial cell dynamics during capillary sprouting. Angiogenesis is defined as the growth of new blood vessels from existing ones and involves multiple cell types including endothelial cells, pericytes, and interstitial cells. The incorporation of these cell types in a physiologically relevant environment, however, represents a challenge for biomimetic model development. Recently, our laboratory has developed the rat mesentery culture model, which enables investigation of angiogenesis in an intact tissue. The objective of this chapter is to detail a protocol for tracking cellular dynamics during angiogenesis using the rat mesentery tissue culture model. The method involves harvesting mesentery tissues from adult SD-EGFP rats, culturing them in MEM + 10% fetal bovine serum, and imaging network regions over the time course of angiogenesis. In example applications, time-lapse comparison of microvascular networks in cultured tissues confirmed dramatic increases in GFP-positive capillary sprouting and GFP-positive segment density. Additionally, tracking of individual capillary sprout extensions revealed their ability to "jump" by disconnecting from one vessel segment and reconnecting to another segment in the network. GFP-positive sprouts were also capable of undergoing subsequent regression. The representative results support the use of the rat mesentery culture model for identifying and tracking cellular dynamics during angiogenesis in intact microvascular networks.

Methylene Blue in Septic Shock-A Novel Weapon in Our Arsenal: Are Utility Studies Highlighting its Futility?

How to cite this article: Angadi VM, Jindal A. Methylene Blue in Septic Shock-A Novel Weapon in Our Arsenal: Are Utility Studies Highlighting its Futility? Indian J Crit Care Med 2024;28(1):89.

Type II Muscle Fiber Capillarization Is an Important Determinant of Post-Exercise Microvascular Perfusion in Older Adults

INTRODUCTION

Microvascular perfusion is essential for post-exercise skeletal muscle recovery to ensure adequate delivery of nutrients and growth factors. This study assessed the relationship between various indices of muscle fiber capillarization and microvascular perfusion assessed by contrast-enhanced ultrasound (CEUS) at rest and during recovery from a bout of resistance exercise in older adults.

METHODS

Sixteen older adults (72 ± 6 y, 5/11 male/female) participated in an experimental test day during which a muscle biopsy was collected from the vastus lateralis and microvascular perfusion was determined by CEUS at rest and at 10 and 40 min following a bout of resistance exercise. Immunohistochemistry was performed on muscle tissue samples to determine various indices of both mixed and fiber-type-specific muscle fiber capillarization.

RESULTS

Microvascular blood volume at t = 10 min was higher compared with rest and t = 40 min (27.2 ± 4.7 vs. 3.9 ± 4.0 and 7.0 ± 4.9 AU, respectively, both p < 0.001). Microvascular blood volume at t = 40 min was higher compared with rest (p < 0.001). No associations were observed between different indices of mixed muscle fiber capillarization and microvascular blood volume at rest and following exercise. A moderate (r = 0.59, p < 0.05) and strong (r = 0.81, p < 0.001) correlation was observed between type II muscle fiber capillary-to-fiber ratio and the microvascular blood volume increase from rest to t = 10 and t = 40 min, respectively. In addition, type II muscle fiber capillary contacts and capillary-to-fiber perimeter exchange index were strongly correlated with the microvascular blood volume increase from rest to t = 40 min (r = 0.66, p < 0.01 and r = 0.64, p < 0.01, respectively).

CONCLUSION

Resistance exercise strongly increases microvascular blood volume for at least 40 min after exercise cessation in older adults. This resistance exercise-induced increase in microvascular blood volume is strongly associated with type II muscle fiber capillarization in older adults.

Activation of mTOR signaling in adult lung microvascular progenitor cells accelerates lung aging

Reactivation and dysregulation of the mTOR signaling pathway are a hallmark of aging and chronic lung disease; however, the impact on microvascular progenitor cells (MVPCs), capillary angiostasis, and tissue homeostasis is unknown. While the existence of an adult lung vascular progenitor has long been hypothesized, these studies show that Abcg2 enriches for a population of angiogenic tissue-resident MVPCs present in both adult mouse and human lungs using functional, lineage, and transcriptomic analyses. These studies link human and mouse MVPC-specific mTORC1 activation to decreased stemness, angiogenic potential, and disruption of p53 and Wnt pathways, with consequent loss of alveolar-capillary structure and function. Following mTOR activation, these MVPCs adapt a unique transcriptome signature and emerge as a venous subpopulation in the angiodiverse microvascular endothelial subclusters. Thus, our findings support a significant role for mTOR in the maintenance of MVPC function and microvascular niche homeostasis as well as a cell-based mechanism driving loss of tissue structure underlying lung aging and the development of emphysema.

Prognostic value of capillary refill time in adult patients: a systematic review with meta-analysis

PURPOSE

Acute circulatory failure leads to tissue hypoperfusion. Capillary refill time (CRT) has been widely studied, but its predictive value remains debated. We conducted a meta-analysis to assess the ability of CRT to predict death or adverse events in a context at risk or confirmed acute circulatory failure in adults.

METHOD

MEDLINE, EMBASE, and Google scholar databases were screened for relevant studies. The pooled area under the ROC curve (AUC ROC), sensitivity, specificity, threshold, and diagnostic odds ratio using a random-effects model were determined. The primary analysis was the ability of abnormal CRT to predict death in patients with acute circulatory failure. Secondary analysis included the ability of CRT to predict death or adverse events in patients at risk or with confirmed acute circulatory failure, the comparison with lactate, and the identification of explanatory factors associated with better accuracy.

RESULTS

A total of 60,656 patients in 23 studies were included. Concerning the primary analysis, the pooled AUC ROC of 13 studies was 0.66 (95%CI [0.59; 0.76]), and pooled sensitivity was 54% (95%CI [43; 64]). The pooled specificity was 72% (95%CI [55; 84]). The pooled diagnostic odds ratio was 3.4 (95%CI [1.4; 8.3]). Concerning the secondary analysis, the pooled AUC ROC of 23 studies was 0.69 (95%CI [0.65; 0.74]). The prognostic value of CRT compared to lactate was not significantly different. High-quality CRT was associated with a greater accuracy.

CONCLUSION

CRT poorly predicted death and adverse events in patients at risk or established acute circulatory failure. Its accuracy is greater when high-quality CRT measurement is performed.

Clinical evaluation of peripheral tissue perfusion as a predictor of mortality in sepsis and septic shock in the intensive care unit: Systematic review and meta-analysis

OBJECTIVE

To determine the diagnostic performance of the clinical evaluation of peripheral tissue perfusion in the prediction of mortality.

DESIGN

Systematic review and meta-analysis.

SETTING

Intensive care unit.

PATIENTS AND PARTICIPANTS

Patients with sepsis and septic shock.

INTERVENTIONS

Studies of patients with sepsis and/or septic shock that associated clinical monitoring of tissue perfusion with mortality were included. A systematic review was performed by searching the PubMed/MEDLINE, Cochrane Library, SCOPUS, and OVID databases.

MAIN VARIABLES OF INTEREST

The risk of bias was assessed with the QUADAS-2 tool. Sensitivity and specificity were calculated to evaluate the predictive accuracy for mortality. Review Manager software version 5.4 was used to draw the forest plot graphs, and Stata version 15.1 was used to build the hierarchical summary receiver operating characteristic model.

RESULTS

Thirteen studies were included, with a total of 1667 patients and 17 analyses. Two articles evaluated the temperature gradient, four evaluated the capillary refill time, and seven evaluated the mottling in the skin. In most studies, the outcome was mortality at 14 or 28 days. The pooled sensitivity of the included studies was 70%, specificity 75.9% (95% CI, 61.6%-86.2%), diagnostic odds ratio 7.41 (95% CI, 3.91-14.04), and positive and negative likelihood ratios 2.91 (95% CI, 1.80-4.72) and 0.39 (95% CI, 0.30-0.51), respectively.

CONCLUSIONS

Clinical evaluation of tissue perfusion at the bedside is a useful tool, with moderate sensitivity and specificity, to identify patients with a higher risk of death among those with sepsis and septic shock.

REGISTRATION

PROSPERO CRD42019134351.

Bone-derived PDGF-BB drives brain vascular calcification in male mice

Brain vascular calcification is a prevalent age-related condition often accompanying neurodegenerative and neuroinflammatory diseases. The pathogenesis of large-vessel calcifications in peripheral tissue is well studied, but microvascular calcification in the brain remains poorly understood. Here, we report that elevated platelet-derived growth factor BB (PDGF-BB) from bone preosteoclasts contributed to cerebrovascular calcification in male mice. Aged male mice had higher serum PDGF-BB levels and a higher incidence of brain calcification compared with young mice, mainly in the thalamus. Transgenic mice with preosteoclast-specific Pdgfb overexpression exhibited elevated serum PDGF-BB levels and recapitulated age-associated thalamic calcification. Conversely, mice with preosteoclast-specific Pdgfb deletion displayed diminished age-associated thalamic calcification. In an ex vivo cerebral microvascular culture system, PDGF-BB dose-dependently promoted vascular calcification. Analysis of osteogenic gene array and single-cell RNA-Seq (scRNA-Seq) revealed that PDGF-BB upregulated multiple osteogenic differentiation genes and the phosphate transporter Slc20a1 in cerebral microvessels. Mechanistically, PDGF-BB stimulated the phosphorylation of its receptor PDGFRβ (p-PDGFRβ) and ERK (p-ERK), leading to the activation of RUNX2. This activation, in turn, induced the transcription of osteoblast differentiation genes in PCs and upregulated Slc20a1 in astrocytes. Thus, bone-derived PDGF-BB induced brain vascular calcification by activating the p-PDGFRβ/p-ERK/RUNX2 signaling cascade in cerebrovascular cells.

The cytokine trio - visfatin, placental growth factor and fractalkine - and their role in myocardial infarction with non-obstructive coronary arteries (MINOCA)

Myocardial infarction with nonobstructive coronary arteries (MINOCA) remains a puzzling clinical entity. It is characterized by clinical evidence of myocardial infarction (MI) with normal or near-normal coronary arteries in angiography. Given the complex etiology including multiple possible scenarios with varied pathogenetic mechanisms, profound investigation of the plausible biomarkers of MINOCA may bring further pathophysiological insights and novel diagnostic opportunities. Cytokines have a great diagnostic potential and are used as biomarkers for many diseases. An unusual trio of visfatin, placental growth factor (PlGF) and fractalkine (CX3CL1) can directly promote vascular dysfunction, inflammation and angiogenesis through the activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling. They are redundant in physiological processes and become overexpressed in the pathomechanisms underlying MINOCA. The knowledge about their concentration might serve as a valuable diagnostic and/or therapeutic tool for assessing vascular endothelial function. Here we analyze the current knowledge on visfatin, PlGF and CX3CL1 in the context of MINOCA and present the novel clinical implications of their combined expression as predictors or indicators of this condition.

Serum Calprotectin as a Potential Predictor of Microvascular Manifestations in Patients with Antiphospholipid Syndrome

INTRODUCTION

Microvascular manifestations constitute a subtype of antiphospholipid syndrome, and those patients have relatively poor prognoses, so it is important to find markers for microvascular manifestations. This study was conducted to explore whether serum calprotectin could be a predictor of microvascular manifestations in antiphospholipid antibody (aPL)-positive patients.

METHODS

Consecutive patients with persistent aPL positivity referred to Peking Union Medical College Hospital and age- and sex-matched health controls (HCs) were included. Microvascular manifestations included antiphospholipid syndrome (APS) nephropathy, livedo reticularis, valvular lesions, non-stroke central nervous system manifestations, myocarditis, catastrophic APS, and other microvascular manifestations confirmed by pathology, imaging, or clinical diagnosis. Calprotectin was measured by an enzyme-linked immunosorbent assay (ELISA). The cutoff value was defined as mean + 2 standard deviations of HCs. Multivariable logistic regression analysis was used to analyze risk factors. Pearson correlation analysis was used to detect the correlation between calprotectin and other laboratory data.

RESULTS

Of the 466 patients included in the study, 281 (60.3%) patients met the 2006 Sydney Revised Classification Criteria; among the latter, 77.2% were patients with primary APS. The mean age was 39.10 ± 13.05 years old, and 77.0% were female. Thirty-eight age- and sex-matched HCs were included in the study. Serum calprotectin levels were increased in aPL-positive patients compared with HCs (649.66 ± 240.79 vs 484.62 ± 149.37 ng/ml, p < 0.001), and were increased in patients with microvascular manifestations compared with patients without (693.03 ± 271.90 vs 639.43 ± 232.06 ng/ml, p = 0.044). The cutoff value was 783.36 ng/ml. Ninety-three patients (20.0%) were positive for calprotectin. Calprotectin positivity was independently associated with microvascular manifestations (odds ratio [OR] 1.90, 95% confidence interval [CI] 1.07-3.36) and platelet count (PLT) < 100 (OR 2.04, 95% CI 1.08-3.88). Age (OR 0.98, 95% CI 0.96-1.00), systemic lupus erythematosus (OR 2.08, 95% CI 1.15-3.75), calprotectin positivity (OR 1.83, 95% CI 1.02-3.26), hypertension (OR 2.73, 95% CI 1.36-5.45), hemolytic anemia (OR 2.66, 95% CI 1.13-6.23), and anti-β2GPI antibodies (OR 2.06, 95% CI 1.11-3.83) could independently predict microvascular manifestations in aPL-positive patients. Serum calprotectin negatively correlated with PLT (R = - 0.101, p = 0.031).

CONCLUSION

Serum calprotectin levels are increased in aPL-positive patients and could be a potential predictor of microvascular manifestations.

Novel transdermal curcumin therapeutic preserves endothelial barrier function in a high-dose LPS rat model

Sepsis is a devastating complication of infection and injury that, through widespread endothelial dysfunction, can cause perfusion deficits and multi-organ failure. To address the recognised need for therapeutics targetting the endothelial barrier, a topical formulation (CUR; VASCEPTOR™; Vascarta Inc, Summit, NJ) was developed to transdermally deliver bio-active concentrations of curcumin-an anti-inflammatory and nitric oxide promoter. Male, Sprague Dawley rats were treated daily with lipopolysaccharide (LPS, 10 mg/kg, IP) to induce endotoxemia, and topical applications of Vehicle Control (LPS + VC; N = 7) or Curcumin (LPS + CUR; N = 7). A third group received neither LPS nor treatment (No-LPS; N = 8). After 72 h, animals were surgically prepared for measurements of physiology and endothelial dysfunction in the exteriorised spinotrapezius muscle through the extravasation of 67 kDa TRITC-BSA (albumin) and 500 kDa FITC-dextran (dextran). At 72 h, LPS + VC saw weight loss, and increases to pulse pressure, lactate, pCO₂, CXCL5 (vs No-LPS) and IL-6 (vs 0 h; p < 0.05). LPS + CUR was similar to No-LPS, but with hypotension. Phenylephrine response was increased in LPS + CUR. Regarding endothelial function, LPS + CUR albumin and dextran extravasation were significantly reduced versus LPS + VC suggesting that Curcumin mitigated endotoxemic endothelial dysfunction. The speculated mechanisms are nitric oxide modulation of the endothelium and/or an indirect anti-inflammatory effect.

Impaired microvascular reactivity in patients treated with 5-fluorouracil chemotherapy regimens: Potential role of endothelial dysfunction

Background

5-fluorouracil (5-FU) is the second most common cancer chemotherapy associated with short- and long-term cardiotoxicity. Although the mechanisms mediating these toxicities are not well understood, patients often present with symptoms suggestive of microvascular dysfunction. We tested the hypotheses that patients undergoing cancer treatment with 5-FU based chemotherapy regimens would present with impaired microvascular reactivity and that these findings would be substantiated by decrements in endothelial nitric oxide synthase (eNOS) gene expression in 5-FU treated human coronary artery endothelial cells (HCAEC).

Methods

We first performed a cross-sectional analysis of 30 patients undergoing 5-FU based chemotherapy treatment for cancer (5-FU) and 32 controls (CON) matched for age, sex, body mass index, and prior health history (excluding cancer). Cutaneous microvascular reactivity was evaluated by laser Doppler flowmetry in response to endothelium-dependent (local skin heating; acetylcholine iontophoresis, ACh) and -independent (sodium nitroprusside iontophoresis, SNP) stimuli. In vitro experiments in HCAEC were completed to assess the effects of 5-FU on eNOS gene expression.

Results

5-FU presented with diminished microvascular reactivity following eNOS-dependent local heating compared to CON (P = 0.001). Iontophoresis of the eNOS inhibitor L-NAME failed to alter the heating response in 5-FU (P = 0.95), despite significant reductions in CON (P = 0.03). These findings were corroborated by lower eNOS gene expression in 5-FU treated HCAEC (P < 0.01) compared to control. Peak vasodilation to ACh (P = 0.58) nor SNP (P = 0.39) were different between groups.

Conclusions

The present findings suggest diminished microvascular function along the eNOS-NO vasodilatory pathway in patients with cancer undergoing treatment with 5-FU-based chemotherapy regimens and thus, may provide insight into the underlying mechanisms of 5-FU cardiotoxicity.

Microcirculatory Monitoring in Children with Congenital Heart Disease Before and After Cardiac Surgery

In this prospective observational study, we investigated whether congenital heart disease (CHD) affects the microcirculation and whether the microcirculation is altered following cardiac surgery with cardiopulmonary bypass (CPB). Thirty-eight children with CHD undergoing cardiac surgery with CPB and 35 children undergoing elective, non-cardiac surgery were included. Repeated non-invasive sublingual microcirculatory measurements were performed with handheld vital microscopy. Before surgery, children with CHD showed similar perfused vessel densities and red blood cell velocities (RBCv) but less perfused vessels (p < 0.001), lower perfusion quality (p < 0.001), and higher small vessel densities (p = 0.039) than children without CHD. After cardiac surgery, perfused vessel densities and perfusion quality of small vessels declined (p = 0.025 and p = 0.032), while RBCv increased (p = 0.032). We demonstrated that CHD was associated with decreased microcirculatory perfusion and increased capillary recruitment. The microcirculation was further impaired after cardiac surgery. Decreased microcirculatory perfusion could be a warning sign for altered tissue oxygenation and requires further exploration.

Resuscitation-associated endotheliopathy (RAsE): a conceptual framework based on a systematic review and meta-analysis

INTRODUCTION

Shock-induced endotheliopathy (SHINE), defined as a profound sympathoadrenal hyperactivation in shock states leading to endothelial activation, glycocalyx damage, and eventual compromise of end-organ perfusion, was first described in 2017. The aggressive resuscitation therapies utilised in treating shock states could potentially lead to further worsening endothelial activation and end-organ dysfunction.

OBJECTIVE

This study aimed to systematically review the literature on resuscitation-associated and resuscitation-induced endotheliopathy.

METHODS

A predetermined structured search of literature published over an 11-year and 6-month period (1 January 2011 to 31 July 2023) was performed in two indexed databases (PubMed/MEDLINE and Embase) per PRISMA guidelines. Inclusion was restricted to original studies published in English (or with English translation) reporting on endothelial dysfunction in critically ill human subjects undergoing resuscitation interventions. Reviews or studies conducted in animals were excluded. Qualitative synthesis of studies meeting the inclusion criteria was performed. Studies reporting comparable biomarkers of endothelial dysfunction post-resuscitation were included in the quantitative meta-analysis.

RESULTS

Thirty-two studies met the inclusion criteria and were included in the final qualitative synthesis. Most of these studies (47%) reported on a combination of mediators released from endothelial cells and biomarkers of glycocalyx breakdown, while only 22% reported on microvascular flow changes. Only ten individual studies were included in the quantitative meta-analysis based on the comparability of the parameters assessed. Eight studies measured syndecan-1, with a heterogeneity index, I2 = 75.85% (pooled effect size, mean = 0.27; 95% CI - 0.07 to 0.60; p = 0.12). Thrombomodulin was measured in four comparable studies (I2 = 78.93%; mean = 0.41; 95% CI - 0.10 to 0.92; p = 0.12). Three studies measured E-selectin (I2 = 50.29%; mean =  - 0.15; 95% CI - 0.64 to 0.33; p = 0.53), and only two were comparable for the microvascular flow index, MFI (I2 = 0%; mean =  - 0.80; 95% CI - 1.35 to - 0.26; p < 0.01).

CONCLUSION

Resuscitation-associated endotheliopathy (RAsE) refers to worsening endothelial dysfunction resulting from acute resuscitative therapies administered in shock states. In the included studies, syndecan-1 had the highest frequency of assessment in the post-resuscitation period, and changes in concentrations showed a statistically significant effect of the resuscitation. There are inadequate data available in this area, and further research and standardisation of the ideal assessment and panel of biomarkers are urgently needed.

Micro- and macrocirculatory effects of norepinephrine on anaesthesia-induced hypotension: a prospective preliminary study

BACKGROUND

Intraoperative arterial hypotension (IOH) leads to increased postoperative morbidity. Norepinephrine is often use to treat IOH. The question regarding the mode of administration in either a bolus or continuous infusion remains unanswered. The aim of the present study was to describe and compare the effects on macrocirculation and microcirculation of a bolus and a continuous infusion of norepinephrine to treat IOH.

METHODS

We conducted a prospective observational study with adult patients who underwent neurosurgery. Patients with invasive arterial blood pressure and cardiac output (CO) monitoring were screened for inclusion. All patients underwent microcirculation monitoring by video-capillaroscopy, laser doppler, near-infrared spectroscopy technology, and tissular CO2. In case of IOH, the patient could receive either a bolus of 10 µg or a continuous infusion of 200 µg/h of norepinephrine. Time analysis for comparison between bolus and continuous infusion were at peak of MAP. The primary outcome was MFI by videocapillaroscopy.

RESULTS

Thirty-five patients were included, with 41 boluses and 33 continuous infusion. Bolus and continuous infusion induced an maximal increase in mean arterial pressure of +30[20-45] and +23[12-34] %, respectively (P=0,07). For macrocirculatory parameters, continuous infusion was associated with a smaller decrease in CO and stroke volume (p<0.05). For microcirculatory parameters, microvascular flow index (-0,1 vs. + 0,3, p=0,03), perfusion index (-12 vs. +12%, p=0,008), total vessel density (-0,2 vs. +2,3 mm2/mm2, p=0,002), showed significant opposite variations with bolus and continuous infusion, respectively.

CONCLUSIONS

These results on macro and microcirculation enlighten the potential benefits of a continuous infusion of norepinephrine rather than a bolus to treat anaesthesia-induced hypotension.

TRIAL REGISTRATION

(NOR-PHARM: 1-17-42 Clinical Trials: NCT03454204), 05/03/2018.

Diabetic microvascular disease in non-classical beds: the hidden impact beyond the retina, the kidney, and the peripheral nerves

Diabetes microangiopathy, a hallmark complication of diabetes, is characterised by structural and functional abnormalities within the intricate network of microvessels beyond well-known and documented target organs, i.e., the retina, kidney, and peripheral nerves. Indeed, an intact microvascular bed is crucial for preserving each organ's specific functions and achieving physiological balance to meet their respective metabolic demands. Therefore, diabetes-related microvascular dysfunction leads to widespread multiorgan consequences in still-overlooked non-traditional target organs such as the brain, the lung, the bone tissue, the skin, the arterial wall, the heart, or the musculoskeletal system. All these organs are vulnerable to the physiopathological mechanisms that cause microvascular damage in diabetes (i.e., hyperglycaemia-induced oxidative stress, inflammation, and endothelial dysfunction) and collectively contribute to abnormalities in the microvessels' structure and function, compromising blood flow and tissue perfusion. However, the microcirculatory networks differ between organs due to variations in haemodynamic, vascular architecture, and affected cells, resulting in a spectrum of clinical presentations. The aim of this review is to focus on the multifaceted nature of microvascular impairment in diabetes through available evidence of specific consequences in often overlooked organs. A better understanding of diabetes microangiopathy in non-target organs provides a broader perspective on the systemic nature of the disease, underscoring the importance of recognising the comprehensive range of complications beyond the classic target sites.