Early outcomes of osteofascial versus osteocutaneous fibula free flap mandibular reconstruction

BACKGROUND

This study compares early outcomes of osteofascial fibula free flap (OF-FFF) with donor-site primary closure and osteocutaneous (OC) FFF with donor-site skin grafting in segmental mandibular reconstruction.

METHODS

A retrospective chart review of FFF mandibular reconstruction patients (2006-2022) divided into OF-FFF and OC-FFF groups. Clinical data, operative parameters, and early postoperative outcomes (≤ 90 days) were analyzed.

RESULTS

The study included 67 patients (39 OF-FFF, 28 OC-FFF). OF-FFF had significantly lower donor-site complications (12.8% vs. 53.6%, p < 0.001) and revision surgeries (7.7% vs. 35.7%, p = 0.004) compared to OC-FFF. Recipient-site (28.2% vs. 25%, p = 0.77) and flap (15.4% vs. 17.9%, p > 0.99) complications were comparable.

CONCLUSIONS

OF-FFF mandibular reconstruction with donor-site primary closure is a safe and reliable technique associated with superior donor-site and comparable flap and recipient-site outcomes to OC-FFF, thus may be considered as a viable alternative to OC-FFF for selected patients.

Perforator-based chimeric ulnar forearm microvascular free tissue transfer reconstruction of post-radiated tracheoesophageal puncture fistulae

Tracheoesophageal puncture (TEP) performed during total laryngectomy in the primary treatment of laryngeal cancer is the standard method for voice restoration. Following adjuvant radiotherapy, the TEP site can experience complications resulting in a tracheoesophageal fistula (TEF) with chronic leakage making oral alimentation unsafe due to aspiration. Here, we describe a technique using chimeric ulnar artery perforator forearm free flaps (UAPFF) in the reconstruction of these complex deformities. Four patients underwent chimeric UAPFF reconstruction of TEP site TEFs following primary TL with TEP and adjuvant radiotherapy. No flap failures or surgical complications occurred. Average time from end of radiotherapy to persistent TEF was 66 months (range 4-190 months). All patients had resolution in their TEF with average time to total oral diet achievement of 22 days (14-42 days). Chimeric UAPFF reconstruction is a safe and effective method to reconstruct recalcitrant TEP site TEFs.

Inhibition of superoxide and iNOS augment cutaneous nitric oxide-dependent vasodilation in non-Hispanic black young adults

We assessed the combined effect of superoxide and iNOS inhibition on microvascular function in non-Hispanic Black and non-Hispanic White participants (n = 15 per group). Participants were instrumented with four microdialysis fibers: (1) lactated Ringer's (control), (2) 10 μM tempol (superoxide inhibition), (3) 0.1 mM 1400 W (iNOS inhibition), (4) tempol + 1400 W. Cutaneous vasodilation was induced via local heating and NO-dependent vasodilation was quantified. At control sites, NO-dependent vasodilation was lower in non-Hispanic Black (45 ± 9% NO) relative to non-Hispanic White (79 ± 9% NO; p < 0.01; effect size, d = 3.78) participants. Tempol (62 ± 16% NO), 1400 W (78 ± 12% NO) and tempol +1400 W (80 ± 13% NO) increased NO-dependent vasodilation in non-Hispanic Black participants relative to control sites (all p < 0.01; d = 1.22, 3.05, 3.03, respectively). The effect of 1400 W (p = 0.04, d = 1.11) and tempol +1400 W (p = 0.03, d = 1.22) was greater than tempol in non-Hispanic Black participants. There was no difference between non-Hispanic Black and non-Hispanic White participants at 1400 W or tempol + 1400 W sites. These data suggest iNOS has a greater effect on NO-dependent vasodilation than superoxide in non-Hispanic Black participants.

Use of a modified microvascular plug to modify fenestration flow in a rapidly failing Fontan

We report a case of an alternative transcatheter use of the modified Medtronic microvascular plug to modify fenestration stent flow in a patient with a rapidly deteriorating clinical condition. This four-year-old boy developed severe cyanosis following fenestration stent insertion, initially placed due to prolonged drainage post-Fontan with extra-cardiac conduit. In April 2023, he underwent urgent cardiac catheterisation and had partial occlusion of fenestration stent with a modified 9Q microvascular plug. His oxygen saturations improved from 50 to 89% in room air with no re-emergence of raised cavopulmonary pressures.

Tensile and Compressive Properties of Woven Fabric Carbon Fiber-Reinforced Polymer Laminates Containing Three-Dimensional Microvascular Channels

Microvascular self-healing composite materials have significant potential for application and their mechanical properties need in-depth investigation. In this paper, the tensile and compressive properties of woven fabric carbon fiber-reinforced polymer (CFRP) laminates containing three-dimensional microvascular channels were investigated experimentally. Several detailed finite element (FE) models were established to simulate the mechanical behavior of the laminate and the effectiveness of different models was examined. The damage propagation process of the microvascular laminates and the influence of microvascular parameters were studied by the validated models. The results show that microvascular channels arranged along the thickness direction (z-direction) of the laminates are critical locations under the loads. The channels have minimal effect on the stiffness of the laminates but cause a certain reduction in strength, which varies approximately linearly with the z-direction channel diameter within its common design range of 0.1~1 mm. It is necessary to consider the resin-rich region formed around microvascular channels in the warp and weft fiber yarns of the woven fabric composite when establishing the FE model. The layers in the model should be assigned with equivalent unidirectional ply material in order to calculate the mechanical properties of laminates correctly.

Effect of Hypotension and Dobutamine on Gastrointestinal Microcirculations of Healthy, Anesthetized Horses

Horses undergoing abdominal exploratory surgery are at risk of hypotension and hypoperfusion. Normal mean arterial pressure is used as a surrogate for adequate tissue perfusion. However, measures of systemic circulation may not be reflective of microcirculation. This study measured the mean arterial pressure, cardiac index, lactate, and four microcirculatory indices in six healthy, anesthetized adult horses undergoing elective laparotomies. The microcirculatory parameters were measured at three different sites along the gastrointestinal tract (oral mucosa, colonic serosa, and rectal mucosa) with dark-field microscopy. All macro- and microcirculatory parameters were obtained when the horses were normotensive, hypotensive, and when normotension returned following treatment with dobutamine. Hypotension was induced with increases in inhaled isoflurane. The horses successfully induced into hypotension did not demonstrate consistent, expected changes in systemic perfusion or microvascular perfusion parameters at any of the three measured gastrointestinal sites. Normotension was successfully restored with the use of dobutamine, while the systemic perfusion and microvascular perfusion parameters remained relatively unchanged. These findings suggest that the use of mean arterial pressure to make clinical decisions regarding perfusion may or may not be accurate.

Assessing the Impact of Prolonged Averaging of Coronary Continuous Thermodilution Traces

Continuous Thermodilution is a novel method of quantifying coronary flow (Q) in mL/min. To account for variability of Q within the cardiac cycle, the trace is smoothened with a 2 s moving average filter. This can sometimes be ineffective due to significant heart rate variability, ventricular extrasystoles, and deep inspiration, resulting in a fluctuating temperature trace and ambiguity in the location of the "steady state". This study aims to assess whether a longer moving average filter would smoothen any fluctuations within the continuous thermodilution traces resulting in improved interpretability and reproducibility on a test-retest basis. Patients with ANOCA underwent repeat continuous thermodilution measurements. Analysis of traces were performed at averages of 10, 15, and 20 s to determine the maximum acceptable average. The maximum acceptable average was subsequently applied as a moving average filter and the traces were re-analysed to assess the practical consequences of a longer moving average. Reproducibility was then assessed and compared to a 2 s moving average. Of the averages tested, only 10 s met the criteria for acceptance. When the data was reanalysed with a 10 s moving average filter, there was no significant improvement in reproducibility, however, it resulted in a 12% diagnostic mismatch. Applying a longer moving average filter to continuous thermodilution data does not improve reproducibility. Furthermore, it results in a loss of fidelity on the traces, and a 12% diagnostic mismatch. Overall, current practice should be maintained.

No-reflow phenomenon in stroke patients: A systematic literature review and meta-analysis of clinical data

BACKGROUND

The no-reflow phenomenon refers to the absence of microvascular reperfusion despite macrovascular reperfusion.

AIM

The aim of this analysis was to summarize the available clinical evidence on no-reflow in patients with acute ischemic stroke.

METHODS

A systematic literature review and a meta-analysis of clinical data on definition, rates, and impact of the no-reflow phenomenon after reperfusion therapy was carried out. A predefined research strategy was formulated according to the Population, Intervention, Comparison, and Outcome (PICO) model and was used to screen for articles in PubMed, MEDLINE, and Embase up to 8 September 2022. Whenever possible, quantitative data were summarized using a random-effects model.

RESULTS

Thirteen studies with a total of 719 patients were included in the final analysis. Most studies (n = 10/13) used variations of the Thrombolysis in Cerebral Infarction scale to evaluate macrovascular reperfusion, whereas microvascular reperfusion and no-reflow were mostly assessed on perfusion maps (n = 9/13). In one-third of stroke patients with successful macrovascular reperfusion (29%, 95% confidence interval (CI), 21-37%), the no-reflow phenomenon was observed. Pooled analysis showed that no-reflow was consistently associated with reduced rates of functional independence (odds ratio (OR), 0.21, 95% CI, 0.15-0.31).

CONCLUSION

The definition of no-reflow varied substantially across studies, but it appears to be a common phenomenon. Some of the no-reflow cases may simply represent remaining vessel occlusions, and it remains unclear whether no-reflow is an epiphenomenon of the infarcted parenchyma or causes infarction. Future studies should focus on standardizing the definition of no-reflow with more consistent definitions of successful macrovascular reperfusion and experimental set-ups that could detect the causality of the observed findings.

Review on In-vitro Techniques and In-vivo Animals Models for Screening Diabetes and Diabetic Complications

Diabetes mellitus is a type of metabolic disorders. Various pharmaceutical interventions and animal models have been used to investigate the genetic, environmental, and etiological aspects of diabetes and its effects. In recent years for the development of ant-diabetic remedies, numerous novel genetically modified animals, pharmaceutical substances, medical techniques, viruses, and hormones have been developed to screen diabetic complications. A unique disease-treating drug with new properties is still being sought after. The current review tried to include all published models and cutting-edge techniques. Experimental induction of diabetes mellitus in animal models and in vitro methods are essential for advancing our knowledge, a thorough grasp of pathophysiology, and the creation of novel therapeutics. Animal models and in vitro techniques are necessary to develop innovative diabetic medications. New approaches and additional animal models are required for diabetes research to advance. This is particularly true for models produced via dietary modifications, which have various macronutrient compositions. In this article, we review the rodent models of diet-induced diabetic peripheral neuropathy, diabetic retinopathy, and diabetic nephropathy and critically compare the key characteristics of these micro-vascular complications in humans and the diagnostic criteria with the parameters used in preclinical research using rodent models, taking into consideration the potential need for factors that can accelerate or aggravate these conditions.

DNase aggravates intestinal microvascular injury in IBD patients by releasing NET-related proteins

Neutrophils accumulate in the inflammatory mucosa of patients with inflammatory bowel disease (IBD), and excessive release of NETs (neutrophil extracellular traps may be one of the important factors that cause IBD progression. However, the specific mechanism underlying vascular injury caused by NETs remains unclear. Immunofluorescence, ELISA, and flow cytometry were used in this study to detect the expression of NETs and DNase in the tissue and peripheral blood samples of patients with IBD. DSS mouse model was used to detect colon injury and vascular permeability. We found that NETs and DNase levels increased in the colon of patients with IBD. We found an increase in the activity of NET-related MPO released by DNase. DNase released NET-related proteins and damaged vascular endothelial cells in vitro. In DSS mouse model, the synchronous increase of DNase and NETs in the colon leads to an increase in vascular injury markers (CD44, sTM). DNase aggravated colon injury and increased vascular permeability in vivo, which was inhibited by gentamicin sulfate (GS). GS does not reduce the expression of DNase, but rather reduces the release of NET-related proteins to protect vascular endothelium by inhibiting DNase activity. MPO and histones synergistically damaged the vascular endothelium, and vascular injury can be improved by their active inhibitors. We further found that H2 O2 is an important substrate for MPO induced vascular damage. In conclusion, in IBD, DNase, and NET levels increased synchronously in the lesion area and released NET-related proteins to damage the vascular endothelium. Therefore, targeting DNase may be beneficial for the treatment of IBD.

Inhibiting Intracellular α2C-Adrenoceptor Surface Translocation Using Decoy Peptides: Identification of an Essential Role of the C-Terminus in Receptor Trafficking

The G protein-coupled α2-adrenoceptor subtype C (abbreviated α2C-AR) has been implicated in peripheral vascular conditions and diseases such as cold feet-hands, Raynaud's phenomenon, and scleroderma, contributing to morbidity and mortality. Microvascular α2C-adrenoceptors are expressed in specialized smooth muscle cells and mediate constriction under physiological conditions and the occlusion of blood supply involving vasospastic episodes and tissue damage under pathological conditions. A crucial step for receptor biological activity is the cell surface trafficking of intracellular receptors, triggered by cAMP-Epac-Rap1A GTPase signaling, which involves protein-protein association with the actin-binding protein filamin-2, mediated by critical amino acid residues in the last 14 amino acids of the receptor carboxyl (C)-terminus. This study assessed the role of the C-terminus in Rap1A GTPase coupled receptor trafficking by domain-swapping studies using recombinant tagged receptors in transient co-transfections and compared with wild-type receptors using immunofluorescence microscopy. We further tested the biological relevance of the α2C-AR C-terminus, when introduced as competitor peptides, to selectively inhibit intracellular α2C-AR surface translocation in transfected as well as in microvascular smooth muscle cells expressing endogenous receptors. These studies contribute to establishing proof of principle to target intracellular α2C-adrenoceptors to reduce biological activity, which in clinical conditions can be a target for therapy.

Histopathological Validation of Microvascular Anastomosis using Two-Throw Reef Knots - An Experimental Study

Background

Knot configuration is an important but relatively neglected topic in microvascular anastomosis literature.

Objective

To study the differences between end-to-end microvascular anastomosis performed with two-throw reef knots as compared to traditional three-throw knots in a rat femoral artery model at the histological level.

Material and Methods

Sprague Dawley rats underwent end-to-end microvascular anastomosis of the right femoral artery (one-way-up method). The rats were divided into two groups: two-throw reef knots versus traditional three-throw knots. The patency was checked by the standard empty refill method. After 2 weeks, the rats underwent re-exploration. An anastomotic segment was sent for histological analysis. Histological alterations including luminal patency and changes in Tunica intima, Tunica media, and Tunica adventitia were compared between the two groups.

Results

Twenty-nine rats were operated on by the senior author (17 by three-throw and 12 by two-throw reef knots). In the two-throw reef knot group versus the traditional three-throw knot group, the immediate patency rates were 100% versus 82.4%, and the delayed patency rates were 90.9% versus 62.5%, respectively. The histopathological patency rates were concordant with delayed patency rates. Subintimal proliferation and fibrosis were comparable in both groups. Adventitial granulomas were noted in all, irrespective of the knotting technique. Tunica media preservation rates for the two-throw reef knot versus the traditional three-throw knot group were 63.6% versus 0%. Five rats were operated by the beginner in the field, all by two-throw reef knots (to assess the safety of this new method in the hands of a beginner).

Conclusion

Microvascular anastomosis performed with two-throw reef knots appears not only feasible but better in terms of anastomosis patency. Histological superiority in terms of Tunica media preservation further validates the technique.

Retinal small vessel narrowing in women with gestational diabetes, pregnancy-associated hypertension, or small-for-gestational age babies

Background

Gestational diabetes, pregnancy-associated hypertension and small-for-gestational age babies are all associated with impaired placental vascularisation. This study compared the effects of these conditions the systemic small vessel calibre that was examined in the retina.

Methods

This was a cross-sectional observational study of consecutive pregnant women recruited from an antenatal clinic. Participants underwent a Glucose Tolerance Test, BP measurements, and were examined for small-for-gestational age babies as per national guidelines. They also underwent retinal photography with a non-mydriatic camera, and vessel calibres were measured with a validated semi-quantitative system at a retinal grading centre. Some participants also underwent testing of retinal vascular responsiveness to a flickering light.

Results

Women with gestational diabetes (n = 68) had a higher mean arterial pressure (85 ± 9 mm Hg) than normal pregnant women (n = 27, 80 ± 8 mmHg, p = 0.01). They also had smaller mean retinal arteriole (147.5 ± 13.6 μm and 159.7 ± 6.7 μm respectively, p < 0.01) and venular calibre (221.0 ± 13.4 μm and 232.8 ± 20.1 μm respectively, p < 0.01) than normal. However their babies' mean birth weights were not different from normal (3,311 ± 558 g and 3,401 ± 600 g respectively, p = 0.48). They also demonstrated a trend to reduced retinal arteriolar dilatation (3.5 ± 1.3%, n = 23) in response to vasodilatory stimuli (4.4 ± 1.8%) (n = 11) (p = 0.08) consistent with endothelial dysfunction. Women with pregnancy-associated hypertension (n = 35) had a higher mean arterial pressure (101 ± 12 mm Hg, p < 0.01), a smaller mean retinal arteriolar calibre (139.9 ± 10.6 μm, p < 0.0001), and a lower baby mean birth weight than for normal pregnancies (3,095 ± 443 g, p = 0.02). Likewise, women with small-for-gestational age babies (n = 31) had a higher mean arterial pressure (89 ± 19 mm Hg, p = 0.03), a smaller mean retinal arteriolar calibre (141.6 ± 12.8 μm, p < 0.01) and a lower baby mean birth weight than for normal pregnancies (2,468 ± 324 g, p < 0.0001).

Conclusion

Mean retinal arterial calibre was reduced in women with gestational diabetes, pregnancy-associated hypertension or small-for-gestational age babies. The reduction in calibre was greatest in pregnancy-associated hypertension and small-for-gestational age babies. Systemic arteriole narrowing may contribute to the pathogenesis of placental vascular dysfunction in these conditions.

Vascular complications of diabetes: A narrative review

Diabetes mellitus is a complex chronic metabolic disease characterized by hyperglycemia and various complications. According to the different pathophysiological mechanisms, these complications can be classified as microvascular or macrovascular complications, which have long-term negative effects on vital organs such as the eyes, kidneys, heart, and brain, and lead to increased patient mortality. Diabetes mellitus is a major global health issue, and its incidence and prevalence have increased significantly in recent years. Moreover, the incidence is expected to continue to rise as more people adopt a Western lifestyle and diet. Thus, it is essential to understand the epidemiology, pathogenesis, risk factors, and treatment of vascular complications to aid patients in managing the disease effectively. This paper provides a comprehensive review of the literature to clarify the above content. Furthermore, this paper also delves into the correlation between novel risk factors, such as long noncoding RNAs, gut microbiota, and nonalcoholic fatty liver disease, with diabetic vascular complications.

Bone reconstruction of extensive maxillomandibular defects in adults

Reconstruction of significant maxillomandibular defects is a challenge that has been much discussed over the last few decades. Fundamental principles were developed decades ago (bone bed viability, graft immobilization). Clinical decision-making criteria are highly relevant, including local/systemic factors and incision designs, the choice of material, grafting technique, and donor site morbidity. Stabilizing particulated grafts for defined defects-that is, via meshes or shells-might allow significant horizontal and vertical augmentation; the alternatives are onlay and inlay techniques. More significant defects might require extra orally harvested autologous bone blocks. The anterior iliac crest is often used for nonvascularized augmentation, whereas more extensive defects often require microvascular reconstruction. In those cases, the free fibula flap has become the standard of care. The development of alternatives is still ongoing (i.e., alloplastic reconstruction, zygomatic implants, obturators, distraction osteogenesis). Especially for these complex procedures, three-dimensional planning tools enable facilitated planning and a surgical workflow.

Ultrastructural characterization of alveolar microvascular damage in severe COVID-19 respiratory failure

Endothelial dysfunction is a key phenomenon in COVID-19, induced by direct viral endothelial infection and secondary inflammation, mainly affecting the microvascular circulation. However, few studies described the subcellular aspects of the lung microvasculature and the associated thrombotic phenomena, which are widely present in severe COVID-19 cases. To that end, in this transversal observational study we performed transmission and scanning electron microscopy in nine lung samples of patients who died due to COVID-19, obtained via minimally invasive autopsies in Sao Paulo, Brazil, in 2020. All patients died due to acute respiratory failure and had microvascular thrombosis at histology. Electron microscopy revealed areas of endothelial damage with basal lamina disruption and virus infection in endothelial cells. In the capillary lumens, the ultrastructure of the thrombi is depicted, with red blood cells stacking, dysmorphism and hemolysis, fibrin meshworks, and extracellular traps. Our description illustrates the complex pathophysiology of microvascular thrombosis at the cellular level, which leads to some of the peculiar characteristics of severe COVID-19.NEW & NOTEWORTHY In this study, electron microscopy was used to explain the pathophysiology of respiratory failure in severe COVID-19. Before the advent of vaccination, as the virus entered the respiratory system, it rapidly progressed to the alveolar capillary network and, before causing exudative alveolar edema, it caused mainly thrombosis of the pulmonary microcirculation with preserved lung compliance explaining "happy hypoxia." Timing of anticoagulation is of pivotal importance in this disease.

Comprehensive Management of ANOCA, Part 1-Definition, Patient Population, and Diagnosis: JACC State-of-the-Art Review

Angina with nonobstructive coronary arteries (ANOCA) is increasingly recognized and may affect nearly one-half of patients undergoing invasive coronary angiography for suspected ischemic heart disease. This working diagnosis encompasses coronary microvascular dysfunction, microvascular and epicardial spasm, myocardial bridging, and other occult coronary abnormalities. Patients with ANOCA often face a high burden of symptoms and may experience repeated presentations to multiple medical providers before receiving a diagnosis. Given the challenges of establishing a diagnosis, patients with ANOCA frequently experience invalidation and recidivism, possibly leading to anxiety and depression. Advances in scientific knowledge and diagnostic testing now allow for routine evaluation of ANOCA noninvasively and in the cardiac catheterization laboratory with coronary function testing (CFT). CFT includes diagnostic coronary angiography, assessment of coronary flow reserve and microcirculatory resistance, provocative testing for endothelial dysfunction and coronary vasospasm, and intravascular imaging for identification of myocardial bridging, with hemodynamic assessment as needed.

Comprehensive Management of ANOCA, Part 2-Program Development, Treatment, and Research Initiatives: JACC State-of-the-Art Review

Centers specializing in coronary function testing are critical to ensure a systematic approach to the diagnosis and treatment of angina with nonobstructive coronary arteries (ANOCA). Management leveraging lifestyle, pharmacology, and device-based therapeutic options for ANOCA can improve angina burden and quality of life in affected patients. Multidisciplinary care teams that can tailor and titrate therapies based on individual patient needs are critical to the success of comprehensive programs. As coronary function testing for ANOCA is more widely adopted, collaborative research initiatives will be fundamental to improve ANOCA care. These efforts will require standardized symptom assessments and data collection, which will propel future large-scale clinical trials.

Assessment of Microvascular Disease in Heart and Brain by MRI: Application in Heart Failure with Preserved Ejection Fraction and Cerebral Small Vessel Disease

The objective of this review is to investigate the commonalities of microvascular (small vessel) disease in heart failure with preserved ejection fraction (HFpEF) and cerebral small vessel disease (CSVD). Furthermore, the review aims to evaluate the current magnetic resonance imaging (MRI) diagnostic techniques for both conditions. By comparing the two conditions, this review seeks to identify potential opportunities to improve the understanding of both HFpEF and CSVD.

Cardiovascular Complications of Diabetes: From Microvascular to Macrovascular Pathways

Diabetes mellitus, with a growing risk of developing complications, has a significant negative impact on cardiovascular health, including microvascular and macrovascular issues. This thorough narrative study methodically examines the complex connection between cardiovascular problems and diabetes. We start by thoroughly introducing diabetes mellitus, classifying its various forms, and discussing its growing global impact. Then, we examine retinopathy, nephropathy, and neuropathy in detail, illuminating their biology, clinical presentations, and treatment options. Moving on to macrovascular consequences, we investigate the complex relationships between diabetes and coronary artery disease, stroke, and peripheral arterial disease, emphasizing risk factors, diagnostic standards, and treatment plans designed for people with diabetes. The review analyzes the pathophysiological pathways that link diabetes to cardiovascular problems, including endothelial dysfunction, chronic inflammation, immune system dysregulation, and oxidative stress brought on by hyperglycemia. Additionally, we review the critical function of risk monitoring, assessment, and predictive tools in early detection. While highlighting current research paths and the need for tailored medical approaches to address this complex health issue, the story also includes prevention and management strategies, ranging from lifestyle changes to developing medications. This narrative review concludes by providing a thorough summary of current information, highlighting research gaps, and advocating for interdisciplinary efforts to reduce the cardiovascular effects of diabetes.

Investigation of Asphalt Self-Healing Capability Using Microvasculars Containing Rejuvenator: Effects of Microvascular Content, Self-Healing Time and Temperature

The oily rejuvenator acted as the healing agent in microvasculars. A tensile test was designed to evaluate the self-healing efficiency of asphalt affected by microvascular number, self-healing time and temperature. It was found that the healing agent was slowly released through the microporous channels on the inner shell of the microvascular. The release modes of the agent can work together to improve the self-healing efficiency. The self-healing values of the three samples (asphalt, asphalt/microvasculars without rejuvenator and asphalt/microvasculars with rejuvenator) are 51%, 53%, and 71%. The self-healing capability of the asphalt samples with a healing agent is much greater than that of the other two without a healing agent at the same time. More microvascular rupture at the asphalt sample interface led to a higher self-healing efficiency. The self-healing efficiency values of the three samples (asphalt samples with one, two, and three microvasculars) are 52%, 67%, and 73%, respectively. The self-healing efficiency of the same sample increased during 1-3 days from 26% to 88% in one self-healing cycle. The self-healing efficiency value indicated that increasing the temperature improved each sample's self-healing efficiency. The above trend of change also applies to the second self-healing process. A higher temperature reduces the resistance to molecular motion and accelerates the molecular action of bitumen and the healing agent. The time-temperature equivalence principle can be fully applied to comprehend asphalt self-healing.

Exercise training rescues impaired H2O2-mediated vasodilation in porcine collateral-dependent coronary arterioles through enhanced K+ channel activation

We previously reported that exercise training drives enhanced agonist-stimulated hydrogen peroxide (H2O2) levels and restores endothelium-dependent dilation via an increased reliance on H2O2 in arterioles isolated from ischemic porcine hearts. In this study, we tested the hypothesis that exercise training would correct impaired H2O2-mediated dilation in coronary arterioles isolated from ischemic myocardium through increases in protein kinase G (PKG) and protein kinase A (PKA) activation and subsequent colocalization with sarcolemmal K+ channels. Female adult Yucatan miniature swine were surgically instrumented with an ameroid constrictor around the proximal left circumflex coronary artery, gradually inducing a collateral-dependent vascular bed. Arterioles (∼125 µm) supplied by the left anterior descending artery served as nonoccluded control vessels. Pigs were separated into exercise (treadmill; 5 days/wk for 14 wk) and sedentary groups. Collateral-dependent arterioles isolated from sedentary pigs were significantly less sensitive to H2O2-induced dilation compared with nonoccluded arterioles, whereas exercise training reversed the impaired sensitivity. Large conductance calcium-activated potassium (BKCa) channels and 4AP-sensitive voltage-gated (Kv) channels contributed significantly to dilation in nonoccluded and collateral-dependent arterioles of exercise-trained but not sedentary pigs. Exercise training significantly increased H2O2-stimulated colocalization of BKCa channels and PKA, but not PKG, in smooth muscle cells of collateral-dependent arterioles compared with other treatment groups. Taken together, our studies suggest that with exercise training, nonoccluded and collateral-dependent coronary arterioles better use H2O2 as a vasodilator through increased coupling with BKCa and 4AP-sensitive Kv channels; changes that are mediated in part by enhanced colocalization of PKA with BKCa channels.NEW & NOTEWORTHY The current study reveals that coronary arterioles distal to stenosis display attenuated dilation responses to H2O2 that are restored with endurance exercise training. Enhanced H2O2 dilation after exercise is dependent on Kv and BKCa channels and at least in part on in colocalization of BKCa channel and PKA and independent of PKA dimerization. These findings expand our earlier studies which demonstrated that exercise training drives beneficial adaptive responses of reactive oxygen species in the microvasculature of the ischemic heart.

New Insights into the Use of Liraglutide-Impact on Cardiovascular Risk and Microvascular Outcomes

Despite the availability of many glucose-lowering drugs, patients with type 2 diabetes mellitus (T2DM) often do not achieve the desired effect, and cardiovascular complications remain the leading cause of death in this group of patients. Recently, more and more attention has been paid to the properties of drugs, with particular emphasis on the possibility of reducing cardiovascular risk. One of them is liraglutide, which belongs to long-acting analogs of glucagon-like peptides-1 (GLP-1); it imitates incretins and causes an increase in insulin secretion. The current study focused on analyzing the efficacy and safety of liraglutide, as well as its impact on microvascular and cardiovascular outcomes in the treatment of patients with T2DM. Hyperglycemia-induced endothelial dysfunction, which is known to play a key role in maintaining cardiovascular homeostasis, is common in diabetes. Liraglutide reduces endothelial dysfunction by reversing damage to endothelial cells. By reducing the generation of reactive oxygen species (ROS), thereby affecting Bax, Bcl-2 protein levels, and restoring signaling pathways, Liraglutide reduces oxidative stress, inflammation, and prevents endothelial cell apoptosis. Liraglutide has beneficial effects on the cardiovascular system; patients with high cardiovascular risk particularly benefit from treatment, as it reduces their major adverse cardiovascular event (MACE) rate, which takes into account cardiovascular death, stroke, and non-fatal myocardial infarction. Liraglutide reduces the occurrence and progression of nephropathy, which is one of the most common microvascular complications of diabetes.

Retinal microvascular changes in patients recovered from COVID-19 compared to healthy controls: a meta-analysis

PURPOSE

To investigate changes in retinal microcirculation in patients recovered from COVID-19 infection compared to healthy controls, using optical coherence tomography-angiography.

METHODS

Meta-analysis of eligible studies comparing retinal microcirculation between patients recovered from COVID-19 infection and healthy controls up to 7^th of September 2022 was performed, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 guidelines. The following search algorithm was used: (COVID-19 OR coronavirus) AND (retina OR optical coherence tomography OR optical coherence tomography angiography OR vessel density OR foveal avascular zone). Standardized Mean Difference (SMD) with 95% confidence interval (CI) was calculated to compare continuous variables. Revman 5.3 was used for the analysis.

RESULTS

12 studies were included in our analysis. Foveal avascular zone (FAZ) area was larger in patients recovered from COVID-19 infection compared to healthy controls, while there was no statistically significant difference in FAZ perimeter between the two groups. The foveal, parafoveal and whole image vessel density in the superficial capillary plexus showed no significant difference between the two groups. The foveal, parafoveal and whole image vessel density in the deep capillary plexus was statistically lower in patients recovered from COVID-19 compared to healthy controls.

CONCLUSION

FAZ area was enlarged and foveal, parafoveal and whole image vessel density in deep capillary plexus were reduced in patients recovered from COVID-19 infection compared to healthy controls, suggesting that COVID-19 infection may induce long-term retinal microvascular changes in patients recovered from the virus infection.

In the Eye of the Cytokine Storm: A Tale of SARS-CoV-2-Induced Acute Macular Neuroretinopathy

Acute macular neuroretinopathy (AMN) commonly affects young to middle-aged females and is considered a relatively rare retinal disease, and the etiology is complex. Advances in multimodal imaging provide a better characterization of retinal disorders and have helped identify that one of the etiologies of AMN is microvascular in nature. This case is clinically relevant as it adds to the literature that the pathophysiology of AMN is vascular-driven. Our case is a 24-year-old Black female with no past medical history, the only medication she was taking was an oral contraceptive pill, who presented to the emergency room with a 24-hour history of left central field vision loss and endorsed a recent upper respiratory tract infection preceding the acute vision loss. It was subsequently found on admission that the patient tested positive for and had a SARS-CoV-2 infection. A retina specialist performed optical coherence tomography (OCT), which showed disruption in the outer segment junction, including the ellipsoid zone and outer plexiform. The use of multimodal imaging like OCT helped confirm AMN; therefore, prompt examination by ophthalmology is critical to confirm a correct diagnosis. This patient’s vision improved and remained stable five months later. This case demonstrates that, like other viruses, SARS-CoV-2 has the potential to cause retinal disease complications such as AMN. These findings reinforce and add to the current literature that SARS-CoV-2 can cause multiple-organ system dysfunction at a vascular level through immune-mediated pathways.

Regulation of Hypoxic-Adenosinergic Signaling by Estrogen: Implications for Microvascular Injury

Loss of estrogen, as occurs with normal aging, leads to increased inflammation, pathologic angiogenesis, impaired mitochondrial function, and microvascular disease. While the influence of estrogens on purinergic pathways is largely unknown, extracellular adenosine, generated at high levels by CD39 and CD73, is known to be anti-inflammatory in the vasculature. To further define the cellular mechanisms necessary for vascular protection, we investigated how estrogen modulates hypoxic-adenosinergic vascular signaling responses and angiogenesis. Expression of estrogen receptors, purinergic mediators inclusive of adenosine, adenosine deaminase (ADA), and ATP were measured in human endothelial cells. Standard tube formation and wound healing assays were performed to assess angiogenesis in vitro. The impacts on purinergic responses in vivo were modeled using cardiac tissue from ovariectomized mice. CD39 and estrogen receptor alpha (ERα) levels were markedly increased in presence of estradiol (E2). Suppression of ERα resulted in decreased CD39 expression. Expression of ENT1 was decreased in an ER-dependent manner. Extracellular ATP and ADA activity levels decreased following E2 exposure while levels of adenosine increased. Phosphorylation of ERK1/2 increased following E2 treatment and was attenuated by blocking adenosine receptor (AR) and ER activity. Estradiol boosted angiogenesis, while inhibition of estrogen decreased tube formation in vitro. Expression of CD39 and phospho-ERK1/2 decreased in cardiac tissues from ovariectomized mice, whereas ENT1 expression increased with expected decreases in blood adenosine levels. Estradiol-induced upregulation of CD39 substantially increases adenosine availability, while augmenting vascular protective signaling responses. Control of CD39 by ERα follows on transcriptional regulation. These data suggest novel therapeutic avenues to explore in the amelioration of post-menopausal cardiovascular disease, by modulation of adenosinergic mechanisms.

Invasive Detection of Coronary Microvascular Dysfunction: How It Began, and Where We Are Now

The landscape of interventional cardiology is ever evolving. Contemporary practice has shifted from a stenosis-centred approach to the total characterisation of both the epicardial and microcirculatory vessels. Microcirculatory dysfunction plays an important role in the pathophysiology of acute and chronic coronary syndromes, and characterisation of the microcirculation has important clinical consequences. Accordingly, the invasive diagnosis of microcirculatory dysfunction is becoming a key feature of the interventional cardiologist's toolkit. This review focuses on the methodology underpinning the invasive diagnosis of microvascular dysfunction and highlights the indices that have arisen from these methodologies.

Impact of CD34-dependent Micro Vessel Density on Periapical Odontogenic Cysts

BACKGROUND/AIM

Odontogenic cysts belong to a type of lesions with endodontic origin that in some cases mimic even aggressive odontogenic tumors sharing with them similar radiographic features. Periapical cysts (PCs) belong to the inflammatory odontogenic cysts sub-category and rarely squamous cell carcinoma arises from their hyperplastic/ dysplastic epithelia. This study aimed to explore the impact of cluster differentiation 34 (CD34) protein expression combined with micro vessel density (MVD) on PCs.

MATERIALS AND METHODS

Forty-eight (n=48) archival, formalin-fixed, and paraffin-embedded PC tissue specimens were included in the study. Immunohistochemistry (IHC) was performed in the corresponding tissue sections using an anti- CD34 antibody. CD34 expression levels and also MVD in the examined cases were measured by implementing a digital image analysis protocol.

RESULTS

CD34 over-expression (moderate to high staining intensity levels) were detected in 29/48 (60.4%) cases, whereas the rest of them (19/48-39.6%) were characterized by low levels of expression. Extended MVD was identified in 26/48 (50.1%) cases correlated with CD34 over-expression, epithelial hyperplasia (p-value=0.001), and marginally with inflammatory infiltration level in the examined lesions (p-value=0.056).

CONCLUSION

CD34 over-expression combined with increased MVD is associated with a neoplastic-like (hyperplastic) phenotype in PCs as a result of increased neo-angiogenic activity. These histopathological characteristics rarely form an eligible substrate for squamous cell carcinoma onset in untended cases.

Effect of Perioperative Antithrombotics on Head and Neck Microvascular Free Flap Survival After Anastomotic Revision

OBJECTIVE

To determine if antithrombotic therapy improves head and neck microvascular free flap survival following anastomotic revision.

STUDY DESIGN

A retrospective review of all patients with microvascular free tissue transfer to the head and neck between August 2013 and July 2021.

SETTING

Otolaryngology-Head and Neck Surgery Departments at University of Alabama at Birmingham, University of Colorado, and University of California Irvine.

METHODS

Perioperative use of anticoagulation, antiplatelets, intraoperative heparin bolus, tissue plasminogen activator (tPA) and vasopressor use, and leech therapy were collected plus microvascular free flap outcomes. The primary endpoint was free flap failure. Analyses of free flaps that underwent anastomotic revision with or without thrombectomy were performed.

RESULTS

A total of 843 microvascular free flaps were included. The overall rate of flap failure was 4.0% (n = 34). The overall rate of pedicle anastomosis revision (artery, vein, or both) was 5.0% (n = 42) with a failure rate of 47.6% (n = 20) after revision. Anastomotic revision significantly increased the risk of flap failure (odds ratio [OR] 52.68, 95% confidence interval [CI] [23.90, 121.1], p < .0001) especially when both the artery and vein were revised (OR 9.425, 95% CI [2.117, 52.33], p = .005). Free flap failure after the anastomotic revision was not affected by postoperative antiplatelet therapy, postoperative prophylactic anticoagulation, intraoperative heparin bolus, tPA, and therapeutic anticoagulation regardless of which vessels were revised and if a thrombus was identified.

CONCLUSION

In cases of microvascular free tissue transfer pedicle anastomotic revision, the use of antithrombotic therapy does not appear to significantly change free flap survival outcomes.

Improved vascular function and functional capacity following l-citrulline administration in patients with heart failure with preserved ejection fraction: a single-arm, open-label, prospective pilot study

There is accumulating evidence for both peripheral vascular dysfunction and impaired functional capacity in patients with heart failure with a preserved ejection fraction (HFpEF). Although derangements in the l-arginine-nitric oxide (l-Arg-NO) pathway are likely to contribute to these aspects of HFpEF pathophysiology, the impact of increased NO substrate on vascular health and physical capacity has not been evaluated in this patient population. Thus, using a single-arm study design, we evaluated the impact of enteral l-citrulline (l-Cit, 6 g/day for 7 days), a precursor for l-Arg biosynthesis, on vascular function [flow-mediated dilation (FMD), reactive hyperemia (RH), and passive limb movement (PLM)], functional capacity [6-min walk test (6MWT)], and biomarkers of l-Arg-NO signaling in 14 patients with HFpEF (n = 14, 4 M/10 F, 70 ± 10 yr, EF: 66 ± 7%). Compared with baseline (0d), 7 days of l-Cit administration improved FMD (0d: 2.5 ± 1.6%, 7d: 4.5 ± 2.9%), RH (0d: 468 ± 167 mL, 7d: 577 ± 199 mL), PLM blood flow area-under-the-curve (0d: 139 ± 130 mL, 7d: 198 ± 115 mL), and 6MWT distance (0d: 377 ± 27 m, 7d: 397 ± 27 m) (P < 0.05). An increase in plasma l-Cit (0d: 42 ± 11 µM/L, 7d: 369 ± 201 µM/L), l-Arg (0d: 65 ± 8 µM/L, 7d: 257 ± 25 µM/L), and the ratio of l-Arg to asymmetric dimethylarginine (ADMA) (0d: 136 ± 13 AU, 7d: 481 ± 49 AU) (P < 0.05) was also observed. Though preliminary in nature, these functional and biomarker assessments demonstrate a potential benefit of l-Cit administration in patients with HFpEF, findings that provide new insight into the mechanisms that govern vascular and physical dysfunction in this patient group.NEW & NOTEWORTHY The current investigation has demonstrated that l-Cit administration may improve brachial artery endothelium-dependent vasodilation, upper and lower limb microvascular function, and physical capacity in patients with HFpEF, highlighting the potential therapeutic potential of interventions targeting the l-Arg-NO signaling cascade to improve outcomes in this patient group.

Functional and structural markers of peripheral microvascular autonomic neuropathy

INTRODUCTION/AIMS

Autonomic dysfunction is a common complication of small-fiber neuropathy (SFN). In this study we aimed to assess the applicability of autonomic microvascular indices as a potential marker for SFN assessment.

METHODS

Fifteen patients with confirmed SFN (idiopathic neuropathy [n = 10], chemotherapy-induced peripheral neuropathy [n = 2], impaired glucose tolerance [n = 1], hereditary transthyretin amyloidosis (hATTR) [n = 1], pulmonary sarcoidosis [n = 1]) and 15 matched control subjects underwent assessment of vascular skin responses assessed through laser Doppler flowmetry and evaluation of microvascular vessel and nerve density in skin biopsies. All participants underwent peripheral autonomic evaluation by quantitative sudomotor axon reflex testing (QSART).

RESULTS

We found no significant differences in vascular skin responses, or in any microvascular skin biopsy markers, when comparing SFN with control subjects. We found no correlation between vascular skin responses and skin biopsy indices. We saw no significant difference in any microvascular indices when comparing subjects with and without impaired sudomotor function.

DISCUSSION

Our findings suggest markers of peripheral microvascular innervation and function are not associated with the diagnosis of SFN. Furthermore, we saw no association between microvascular markers and sudomotor function, suggesting that these are independent and unrelated components of the autonomic nervous system.

Retinal Vascular Changes in Alzheimer's Dementia and Mild Cognitive Impairment: A Pilot Study Using Ultra-Widefield Imaging

Purpose

Retinal microvascular abnormalities measured on retinal images are a potential source of prognostic biomarkers of vascular changes in the neurodegenerating brain. We assessed the presence of these abnormalities in Alzheimer's dementia and mild cognitive impairment (MCI) using ultra-widefield (UWF) retinal imaging.

Methods

UWF images from 103 participants (28 with Alzheimer's dementia, 30 with MCI, and 45 with normal cognition) underwent analysis to quantify measures of retinal vascular branching complexity, width, and tortuosity.

Results

Participants with Alzheimer's dementia displayed increased vessel branching in the midperipheral retina and increased arteriolar thinning. Participants with MCI displayed increased rates of arteriolar and venular thinning and a trend for decreased vessel branching.

Conclusions

Statistically significant differences in the retinal vasculature in peripheral regions of the retina were observed among the distinct cognitive stages. However, larger studies are required to establish the clinical importance of our findings. UWF imaging may be a promising modality to assess a larger view of the retinal vasculature to uncover retinal changes in Alzheimer's disease.

Translational Relevance

This pilot work reports an investigation into which retinal vasculature measurements may be useful surrogate measures of cognitive decline, as well as technical developments (e.g., measurement standardization), that are first required to establish their recommended use and translational potential.

MIRNA146a And Diabetes-Related Complications: A Review

Diabetes mellitus, defined as long-standing hyperglycemic conditions caused by a defect in insulin production and activity, has become a major healthcare burden as the number of catastrophic and life-threatening complications rises. Microvascular complications (neuropathy, retinopathy, and nephropathy), and also diabetes-related macrovascular complications are common problems that arise as the life expectancy of diabetic patients has increased despite improved treatment options. While it is impossible to pinpoint the specific crucial timing when the complications become fully entrenched, looking for novel sensitive biomarkers to identify physiological changes in the initial stages would be needed. An increasing amount of data shows that miRNAs, particularly miRNA146a, are stable in a range of body fluids and can be used to identify pathogenic changes at the cellular or tissue level. In this brief review, we highlight the important functioning of miRNA146a and its putative target of action in diabetic microvascular and cardiovascular complications. A decrease in miRNA146a levels may play a critical role in the onset and development of diabetes complications, whereas its anti-inflammatory properties were revealed to be associated with the pathogenesis of numerous diabetic complications, including diabetic nephropathy, retinopathy, neuropathy, and diabetes-related cardiovascular disorders, even tending to be a potential biomarker of the disease's inflammatory status.

Efficacy and safety of intensive versus conventional glucose targets in people with type 2 diabetes: a systematic review and meta-analysis

OBJECTIVE

The aim of study is to re-evaluate the risk-benefits of intensive glycemic control in the context of multi-factorial intervention in adults with T2D.

METHODS

We searched Ovid MEDLINE, Embase, Cochrane, and CINHAL for randomized control trials comparing standard glucose targets to intensive glucose targets with pre-specified HbA_1clevels. Subgroup analysis was also performed to account for the inclusion of glucose only versus multi-factorial intervention trials. Results are reported as risk ratio (RR) and 95% confidence interval (CI).

RESULTS

Fifty-seven publications including 19 trials were included. Compared to conventional glycemic control, intensive glycemic control decreased the risk of non-fatal myocardial infarction (0.8, 0.7-0.91), macroalbuminuria (0.72, 0.5--0.87), microalbuminuria (0.67, 0.52-0.85), major amputation (0.6, 0.38-0.96), retinopathy (0.75 ,0.63-0.9), and nephropathy (0.78, 0.63-0.97). The risk of hypoglycemia increased with intensive glycemic control than conventional treatment (2.04, 1.34-3.1). No reduction in all-cause or cardiovascular mortality was observed. However, in the context of multifactorial intervention, intensive glucose control was associated with a significant reduction in all-cause mortality (0.74, 0.57-0.95).

CONCLUSION

Targeting HbA_1c levels should be individualized based on the clinical status, balancing risks and benefits and potential risk for developing these complications among people with T2D.

Metabolic and microvascular function assessed using near-infrared spectroscopy with vascular occlusion in women: age differences and reliability

NEW FINDINGS

What is the central question of this study? Can the near-infrared spectroscopy with vascular occlusion test (NIRS-VOT) reliably measure skeletal muscle metabolic and microvascular function in women? What is the main finding and its importance? The NIRS-VOT can be used as a reliable technique for the assessment of skeletal muscle metabolism and microvascular function in women, with reliability being generally greater in younger women. These findings have important implications for the planning and development of future studies employing the NIRS-VOT in women, and provide insights into the effects of age on these parameters in women specifically.

ABSTRACT

We investigated the test-retest reliability of, and age-related differences in, markers of skeletal muscle metabolism and microvascular function derived from the near-infrared spectroscopy with vascular occlusion test (NIRS-VOT) in younger women (YW) and middle-aged and older women (MAOW). Seventeen YW (age 23 ± 4 years) and 17 MAOW (age 59 ± 8 years) completed this study. Participants completed identical experimental visits separated by ∼4 weeks during which the NIRS-VOT was used to quantify the occlusion slope, minimum and maximum tissue saturation, ischaemic index, reperfusion magnitude, the reperfusion and 10-s reperfusion slopes (slope 2 and slope 210-s ), time to max tissue saturation, and area under the reperfusion curve using the local tissue oxygen saturation signal. Except for slope 210-s (intraclass correlation coefficient (ICC) = 0.37; coefficient of variation (CV) = 31%), time to max tissue saturation (ICC = 0.21), and ischaemic index (ICC = 0.37) for MAOW, all of the NIRS variables demonstrated good to excellent relative reliability for the YW (ICCs = 0.74-0.86) and the MAOW (ICCs = 0.51-0.87), with CVs of 2-21% and 2-22%, respectively. The occlusion slope was significantly lower, indicating accelerated deoxygenation, while maximum tissue saturation, reperfusion magnitude, and ischaemic index were significantly higher in YW versus MAOW. No other group differences were found. In conclusion, our data support the use of the NIRS-VOT as a simple, reliable, non-invasive technique for the assessment of peripheral skeletal muscle metabolism and microvascular function in women, with the reliability being generally greater in YW versus MAOW. Further, our data suggest that ageing is associated with lower skeletal muscle metabolism and microvascular hyperaemic responsiveness in women.

A Successful Non-microsurgical Thumb Reconstruction by Using the Skeletonized Amputated Phalanges, After a Failed Trial of Microsurgical Replantation: A Case Report

We present a case of thumb reconstruction free of microsurgical technique or free tissue transfer producing satisfactory function. The patient who underwent reconstruction is a 40-year-old right-handed male mechanic, medically free, non-smoker. After unsuccessful microsurgical replantation of the amputated thumb, we elected to pursue regional reconstruction options using a reverse radial forearm flap and the skeletonized phalanges obtained from the amputated thumb as a bony scaffold.

Association Between Meeting Physical Activity Time-Intensity Guidelines With Ambulation, Quality of Life, and Inflammation in Claudication

PURPOSE

The aim of this investigation was to determine if meeting the 2018 physical activity (PA) time-intensity guidelines was associated with better ambulatory function, health-related quality of life (HRQoL), vascular function, and inflammation than failing to meet the guidelines in patients with peripheral artery disease and claudication. Second, we determined the optimal number of total steps/d and steps taken at moderate cadence needed to meet the PA time-intensity guidelines.

METHODS

Five hundred seventy-two patients were assessed on daily ambulatory activity for 1 wk with a step activity monitor, and were grouped according to whether they achieved <150 min/wk of moderate-intensity PA (group 1 = do not meet guidelines; n = 397) or whether they were above this threshold (group 2 = meet guidelines; n = 175).

RESULTS

Treadmill peak walking time (mean ± SD) was higher ( P < .001) in group 2 (709 ± 359 sec) than in group 1 (427 ± 281 sec). The physical function HRQoL score was higher ( P < .001) in group 2 (61 ± 22%) than in group 1 (44 ± 21%). High-sensitivity C-reactive protein was lower ( P < .001) in group 2 (3.6 ± 4.5 mg/L) than in group 1 (5.9 ± 6.1 mg/L). Finally, ≥7675 total steps/d and ≥1660 steps/d at moderate cadence were optimal thresholds associated with meeting PA guidelines.

CONCLUSIONS

Patients with claudication who meet the 2018 PA time-intensity guidelines for US adults had better ambulation, HRQoL, and vascular outcomes than those who failed to meet the PA guidelines. Patients with claudication best achieved the PA time-intensity guidelines by taking ≥7675 total steps/d, and ≥1660 steps/d at a moderate cadence.

Capillary communication: the role of capillaries in sensing the tissue environment, coordinating the microvascular, and controlling blood flow

Historically, capillaries have been viewed as the microvascular site for flux of nutrients to cells and removal of waste products. Capillaries are the most numerous blood vessel segment within the tissue, whose vascular wall consists of only a single layer of endothelial cells and are situated within microns of each cell of the tissue, all of which optimizes capillaries for the exchange of nutrients between the blood compartment and the interstitial space of tissues. There is, however, a growing body of evidence to support that capillaries play an important role in sensing the tissue environment, coordinating microvascular network responses, and controlling blood flow. Much of our growing understanding of capillaries stems from work in skeletal muscle and more recent work in the brain, where capillaries can be stimulated by products released from cells of the tissue during increased activity and are able to communicate with upstream and downstream vascular segments, enabling capillaries to sense the activity levels of the tissue and send signals to the microvascular network to coordinate the blood flow response. This review will focus on the emerging role that capillaries play in communication between cells of the tissue and the vascular network required to direct blood flow to active cells in skeletal muscle and the brain. We will also highlight the emerging central role that disruptions in capillary communication may play in blood flow dysregulation, pathophysiology, and disease.

Selenocompounds and Sepsis-Redox Bypass Hypothesis: Part B-Selenocompounds in the Management of Early Sepsis

Significance: Endothelial barrier damage, which is in part caused by excess production of reactive oxygen, halogen and nitrogen species (ROHNS), especially peroxynitrite (ONOO^-), is a major event in early sepsis and, with leukocyte hyperactivation, part of the generalized dysregulated immune response to infection, which may even become a complex maladaptive state. Selenoenzymes have major antioxidant functions. Their synthesis is related to the need to limit deleterious oxidant redox cycling by small selenocompounds, which may be of therapeutic cytotoxic interest. Plasma selenoprotein-P is crucial for selenium transport from the liver to the tissues and for antioxidant endothelial protection, especially against ONOO^-. Above micromolar concentrations, sodium selenite (Na₂SeO₃) becomes cytotoxic, with a lower cytotoxicity threshold in activated cells, which has led to cancer research. Recent Advances: Plasma selenium (<2% of total body selenium) is mainly contained in selenoprotein-P, and concentrations decrease rapidly in the early phase of sepsis, because of increased selenoprotein-P binding and downregulation of hepatic synthesis and excretion. At low concentrations, Na₂SeO₃ acts as a selenium donor, favoring selenoprotein-P synthesis in physiology, but probably not in the acute phase of sepsis. Critical Issues: The cytotoxic effects of Na₂SeO₃ against hyperactivated leukocytes, especially the most immature forms that liberate ROHNS, may be beneficial, but they may also be harmful for activated endothelial cells. Endothelial protection against ROHNS by selenoprotein-P may reduce Na₂SeO₃ toxicity, which is increased in sepsis. Future Direction: The combination of selenoprotein-P for endothelial protection and the cytotoxic effects of Na₂SeO₃ against hyperactivated leukocytes may be a promising intervention for early sepsis. Antioxid. Redox Signal. 37, 998-1029.

High Glycemia and Soluble Epoxide Hydrolase in Females: Differential Multiomics in Murine Brain Microvasculature

The effect of a high glycemic diet (HGD) on brain microvasculature is a crucial, yet understudied research topic, especially in females. This study aimed to determine the transcriptomic changes in female brain hippocampal microvasculature induced by a HGD and characterize the response to a soluble epoxide hydrolase inhibitor (sEHI) as a mechanism for increased epoxyeicosatrienoic acids (EETs) levels shown to be protective in prior models of brain injury. We fed mice a HGD or a low glycemic diet (LGD), with/without the sEHI (t-AUCB), for 12 weeks. Using microarray, we assessed differentially expressed protein-coding and noncoding genes, functional pathways, and transcription factors from laser-captured hippocampal microvessels. We demonstrated for the first time in females that the HGD had an opposite gene expression profile compared to the LGD and differentially expressed 506 genes, primarily downregulated, with functions related to cell signaling, cell adhesion, cellular metabolism, and neurodegenerative diseases. The sEHI modified the transcriptome of female mice consuming the LGD more than the HGD by modulating genes involved in metabolic pathways that synthesize neuroprotective EETs and associated with a higher EETs/dihydroxyeicosatrienoic acids (DHETs) ratio. Our findings have implications for sEHIs as promising therapeutic targets for the microvascular dysfunction that accompanies vascular dementia.

Prenatal exposure to a low dose of BPS causes sex-dependent alterations to vascular endothelial function in adult offspring

Background: Bisphenol S (BPS) is among the most commonly used substitutes for Bisphenol A (BPA), an endocrine disrupting chemical used as a plasticizer in the manufacture of polycarbonate plastics and epoxy resins. Bisphenols interfere with estrogen receptor (ER) signaling, which modulates vascular function through stimulation of nitric oxide (NO) production via endothelial nitric oxide synthase (eNOS). BPS can cross into the placenta and accumulates in the fetal compartment to a greater extent than BPA, potentially interfering with key developmental events. Little is known regarding the developmental impact of exposure to BPA substitutes, particularly with respect to the vasculature.

Objective: To determine if prenatal BPS exposure influences vascular health in adulthood.

Methods: At the time of mating, female C57BL/6 dams were administered BPS (250 nM) or vehicle control in the drinking water, and exposure continued during lactation. At 12-week of age, mesenteric arteries were excised from male and female offspring and assessed for responses to an endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside, SNP) vasodilator. Endothelium-dependent dilation was measured in the presence or absence of L-NAME, an eNOS inhibitor. To further explore the role of NO and ER signaling, wire myography was used to assess ACh responses in aortic rings after acute exposure to BPS in the presence or absence of L-NAME or an ER antagonist.

Results: Increased ACh dilation and increased sensitivity to Phe were observed in microvessels from BPS-exposed females, while no changes were observed in male offspring. Differences in ACh-induced dilation between control or BPS-exposed females were eliminated with L-NAME. Increased dilatory responses to ACh after acute BPS exposure were observed in aortic rings from female mice only, and differences were eliminated with inhibition of eNOS or inhibition of ER.

Conclusion: Prenatal BPS exposure leads to persistent changes in endothelium-dependent vascular function in a sex-specific manner that appears to be modulated by interaction of BPS with ER signaling.

Adipose stromal vascular fraction reverses mitochondrial dysfunction and hyperfission in aging-induced coronary microvascular disease

Aging is associated with blunted coronary microvascular vasodilatory function. Previously, systemically administered adipose stromal vascular fraction (SVF) therapy reversed aging-induced attenuation of β1-adrenergic- and flow-mediated dilation dependent on reducing mitochondrial reactive oxygen species. We hypothesized that SVF-mediated recovery of microvascular dilatory function is dependent on recovery of mitochondrial function, specifically by reducing mitochondrial hyperfission. Female Fischer-344 rats were allocated into young control, old control, and old + SVF therapy groups. Pressure myography, immunofluorescent staining, Western blot analysis, and RNA sequencing were performed to determine coronary microvascular mitochondrial dynamics and function. Gene and protein expression of fission-mediator DRP-1 was enhanced with aging but reversed by SVF therapy. SVF facilitated an increase in fusion-mediator MFN-1 gene and protein expression. Mitochondrial morphology was characterized as rod-like and densely networked in young controls, isolated circular and punctate with aging, and less circularity with partially restored mitochondrial branch density with SVF therapy. Decreased mitochondrial membrane potential and ATP bioavailability in aged animals at baseline and during flow-mediated dilation were reversed by SVF and accompanied with enhanced oxygen consumption. Dilation to norepinephrine and flow in young controls were dependent on uninhibited mitochondrial fusion, whereas inhibiting fission did not restore aged microvessel response to norepinephrine or flow. SVF-mediated recovery of β-adrenergic function was dependent on uninhibited mitochondrial fusion, whereas recovery of flow-mediated dilation was dependent on maintained mitochondrial fission. Impaired dilation in aging is mitigated by SVF therapy, which recovers mitochondrial function and fission/fusion balance.NEW & NOTEWORTHY We elucidated the consequences of aging on coronary microvascular mitochondrial health as well as SVF's ability to reverse these effects. Aging shifts gene/protein expression and mitochondrial morphology indicating hyperfission, alongside attenuated mitochondrial membrane potential and ATP bioavailability, all reversed using SVF therapy. Mitochondrial membrane potential and ATP levels correlated with vasodilatory efficiency. Mitochondrial dysfunction is a contributing pathological factor in aging that can be targeted by therapeutic SVF to preserve microvascular dilative function.

Poorly controlled hypertension is associated with increased coronary myogenic tone in patients undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVE

Cardioplegia and cardiopulmonary bypass dysregulate coronary vasomotor tone, which can be further affected by common comorbidities in patients undergoing cardiac surgery. This study investigates differences in coronary myogenic tone and vasomotor responses to phenylephrine before and after cardioplegia and cardiopulmonary bypass based on hypertension history.

METHODS

Coronary arterioles before and after cardioplegia and cardiopulmonary bypass were dissected from atrial tissue samples in patients with no hypertension, well-controlled hypertension, or uncontrolled hypertension, as determined by documented history of hypertension, antihypertensive agent use, and clinical blood pressure measurements averaged over 1 year. Myogenic tone in response to stepwise increases in intraluminal pressure was studied between pressure steps. Microvascular reactivity in response to phenylephrine was assessed via vessel myography. Protein expression was measured with immunoblotting.

RESULTS

Coronary myogenic tone was significantly increased in the uncontrolled hypertension group compared with the no hypertension and well-controlled hypertension groups before cardioplegia and cardiopulmonary bypass at higher intraluminal pressures, and after cardioplegia and cardiopulmonary bypass across all intraluminal pressures (P < .05). Contractile responses to phenylephrine were significantly enhanced in patients in the uncontrolled hypertension group compared with the well-controlled hypertension group before cardioplegia and cardiopulmonary bypass, and in the uncontrolled hypertension group compared with the no hypertension and well-controlled hyertension groups after cardioplegia and cardiopulmonary bypass (P < .05). There were no differences in myogenic tone or phenylephrine-induced reactivity between the no hypertension and well-controlled hypertension groups (P > .05). There was increased expression of phosphorylated protein kinase C alpha in the uncontrolled hypertension group after cardiopulmonary bypass compared with before cardiopulmonary bypass and increased phosphorylated extracellular signal-regulated kinase 1/2 in the uncontrolled hypertension compared with the no hypertension group after cardiopulmonary bypass (P < .05).

CONCLUSIONS

Uncontrolled hypertension is associated with increased coronary myogenic tone and vasoconstrictive response to phenylephrine that persists after cardioplegia and cardiopulmonary bypass.

A Microvascular System Self-Healing Approach on Polymeric Composite Materials

The paper addresses the synthesis of a nano-fibre network by coaxial electrospinning, embedding the healing agent dicyclopentadiene (DCPD) in polyacrylonitrile (PAN) fibres. Compared to other encapsulation methods, the use of nano-fibres filled with healing agent have no effect on the mechanical properties of the matrix and can address a larger healing area. Additionally, carbon nanotubes were added as nanofillers to enhance the reactivity between DCPD and the epoxydic matrix. The self-healing capability of the nano-fibre network was carried out by flexural tests, at epoxy resin level and composite level. Results obtained from Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) confirmed the successful encapsulation of DCPD healing agent in PAN fibres. Flexural tests indicate that after 48 h, the epoxy resin has recovered 84% of its flexural strength while the composite material recovered 93%.

Skeletal Muscle Tissue Saturation Changes Measured Using Near Infrared Spectroscopy During Exercise Are Associated With Post-Occlusive Reactive Hyperaemia

Measuring local haemodynamics in skeletal muscle has the potential to provide valuable insight into the oxygen delivery to tissue, especially during high demand situations such as exercise. The aim of this study was to compare the skeletal muscle microvascular response during post-occlusive reactive hyperaemia (PORH) with the response to exercise, each measured using near-infrared spectroscopy (NIRS) and to establish if associations exist between muscle measures and exercise capacity or sex. Participants were from a population-based cohort study, the Southall and Brent Revisited (SABRE) study. Skeletal muscle measures included changes in tissue saturation index at the onset of exercise (∆TSIBL-INC) and across the whole of exercise (∆TSIBL-EE), time to 50%, 95% and 100% PORH, rate of PORH recovery, area under the curve (AUC) and total oxygenated Haemoglobin (oxy-Hb) change during PORH. Exercise capacity was measured using a 6-min stepper test (6MST). Analysis was by multiple linear regression. In total, 558 participants completed the 6MST with NIRS measures of TSI (mean age±SD: 73 ± 7years, 59% male). A sub-set of 149 participants also undertook the arterial occlusion. Time to 100% PORH, recovery rate, AUC and ∆oxy-Hb were all associated with ∆TSIBL-EE (β-coefficient (95%CI): 0.05 (0.01, 0.09), p = 0.012; -47 (-85, -9.9), p = 0.014; 1.7 (0.62, 2.8), p = 0.002; 0.04 (0.002.0.108), p = 0.041, respectively). Time to 95% & 100% PORH, AUC and ∆oxy-Hb were all associated with ∆TSIBL-INC (β-coefficient (95%CI): -0.07 (-0.12,-0.02), p = 0.02; -0.03 (-0.05, -0.003), p = 0.028; 0.85 (0.18, 1.5), p = 0.013 & 0.05 (0.02, 0.09), p = 0.001, respectively). AUC and ∆Oxy-Hb were associated with steps achieved (β-coefficient (95%CI): 18.0 (2.3, 33.7), p = 0.025; 0.86 (0.10, 1.6), p = 0.027). ∆TSIBL-EE was associated with steps and highest VO2 (1.7 (0.49, 2.9), p = 0.006; 7.7 (3.2, 12.3), p = 0.001). ∆TSIBL-INC was associated with steps and VO2 but this difference was attenuated towards the null after adjustment for age, sex and ethnicity. ∆TSIBL-EE was greater in women (3.4 (0.4, 8.9) versus 2.1 (0.3, 7.4), p = 0.017) and ∆TSIBL-INC was lower in women versus men (2.4 (0.2, 10.2) versus 3.2 (0.2, 18.2), p = 0.016). These Local microvascular NIRS-measures are associated with exercise capacity in older adults and several measures can detect differences in microvascular reactivity between a community-based sample of men and women.