A mitochondrial program encodes brain vascular reserve

The coronary collateral circulation revisited

During angiogenesis, vascular endothelial growth factor A (VEGFA) regulates endothelial cell (EC) survival, tip cell formation, and stalk cell proliferation via VEGF receptor 2 (VEGFR2). VEGFR2 can interact with VEGFR2 co-receptors such as heparan sulfate proteoglycans (HSPGs) and neuropilin 2 (NRP2), but the exact roles of these co-receptors, or of sulfatase 2 (SULF2), an enzyme that removes sulfate groups from HSPGs and inhibits HSPG-mediated uptake of very low density lipoprotein (VLDL), in angiogenesis and tip cell biology are unknown. In the present study, we investigated whether the modulation of binding of VEGFA to VEGFR2 by knockdown of SULF2 or NRP2 affects sprouting angiogenesis, tip cell formation, proliferation of non-tip cells, and EC survival, or uptake of VLDL. To this end, we employed VEGFA splice variant 121, which lacks an HSPG binding domain, and VEGFA splice variant 165, which does have this domain, in in vitro models of angiogenic tip cells and vascular sprouting. We conclude that VEGFA165 and VEGFA121 have similar inducing effects on tip cells and sprouting in vitro, and that the binding of VEGFA165 to HSPGs in the extracellular matrix does not seem to play a role, as knockdown of SULF2 did not alter these effects. Co-binding of NRP2 appears to regulate VEGFA–VEGFR2-induced sprout initiation, but not tip cell formation. Finally, as the addition of VLDL increased sprout formation but not tip cell formation, and as VLDL uptake was limited to non-tip cells, our findings suggest that VLDL plays a role in sprout formation by providing biomass for stalk cell proliferation.

The Orphan Receptor Tie1 Controls Angiogenesis and Vascular Remodeling by Differentially Regulating Tie2 in Tip and Stalk Cells.

Mitochondria fulfill the massive energy demands of the human heart through oxidative phosphorylation (OXPHOS) which couples nutrient oxidation and the reduction of molecular oxygen (O2) to the phosphorylation of ADP. Reactive oxygen species (ROS) are also generated during OXPHOS which can be damaging at high levels but serve as secondary messengers when produced in a controlled manner. Here, I review how disruption of control over mitochondrial ROS production can lead to the pathogenesis of a range of cardiovascular diseases (CVD) including decompensated left ventricular hypertrophy, alcoholic and diabetic hypertrophy, myocardial infarction (MI), ischemic-reperfusion injury (IR), and heart failure. In particular I focus on the function of protein S-glutathionylation (PGlu) reactions, a rapid and reversible redox signaling mechanism that involves the conjugation and removal of glutathione from cysteine switches, in the modulation of ROS production in myocardial mitochondria and how these reactions become deregulated in heart disease. I also discuss the use of mitochondria penetrating antioxidants in the treatment of heart disease. I propose that heart disease related to deregulated PGlu reactions can be treated with a novel and hypothetical class of mitochondria penetrating reduced glutathione (GSH) molecules called MitoGSH. This synthetic form of GSH can be tagged with either SS peptides or triphenylphosphonium ions to ensure accumulation in mitochondria which could restore glutathione levels and preserve redox buffering networks. Mitochondria penetrating antioxidants have been shown to be efficient at restoring mitochondrial antioxidant defense in CVD. However, CVD and various other disorders are associated with a depletion of GSH pools. Use of mitochondria-targeted GSH analogs could serve as a more efficient means of treating heart disease since it would allow for the direct restoration of GSH levels and preserve mitochondrial redox buffering and signaling capacity.

BackgroundThe quantification of the flow returning from the head through the cervical veins and the collaterals of the internal jugular vein (IJV), is becoming of prominent interest in clinical practice. We developed a novel model to calculate the cerebral venous return, normalized to the arterial inflow, in the different segments of the IJV.MethodsWe assessed, by established Echo Colour Doppler (ECD) methodology, the head inflow (HBinF) defined as the sum of common carotids and vertebral arteries, as well as the cerebral flow (CBF) defined as the sum of internal carotid and vertebral arteries. We also assessed the head outflow (HBoutF) defined as the sum of the measurements at the junction of the IJV and the vertebral veins. In addition, we also calculated the collateral flow index (CFI) by estimating the flow which re-enters directly into the superior vena cava as the amount of blood extrapolated by the difference between the HBinF and the HBoutF. We preliminarily tested the model by comparing ten healthy controls (HC) with ten patients affected by chronic cerebral spinal venous insufficiency (CCSVI), a condition characterized by some blockages in the IJV which are bypassed by collateral circulation.ResultsIn HC the HBinF was 956+-105ml/min, whereas the HBoutF was > 90% of the HBinF, leading to a final CFI value of 1%. The last result shows that a very small amount of blood is drained by the collaterals. In upright we confirmed a reduction of the outflow through the IJV which increased CFI to 9%. When we applied the model to CCSVI, the HBinF was not significantly different from controls. In supine, the flow of CCSVI patients in the IJV junction was significantly lower (p < 0.001) while the correspondent CFI value significantly increased (61%, p < 0.0002).ConclusionsOur preliminary application of the novel model in the clinical setting suggests the pivotal role of the collateral network in draining the blood into the superior vena cava under CCSVI condition.

Moyamoya syndrome (MMS) is a chronic cerebrovascular disorder characterized by occlusion or stenosis of the internal carotid arteries with the formation of abnormal collateral vascular networks. Moreover, the development of MMS, which is a distinct category from "moyamoya disease," is attributed to the underlying disease, while some cases of MMS related to systemic lupus erythematosus (SLE) have been previously reported. Herein, we present the case of a 29-year-old Japanese woman with SLE in whom intracranial hemorrhage ascribable to MMS developed during pregnancy. Craniotomy was performed to remove hematoma, and prednisolone, tacrolimus, and hydroxychloroquine were consecutively administered. She ultimately achieved remission and childbearing without the relapse of cerebrovascular event. To our knowledge, this is the first report of MMS associated with SLE in pregnancy. Through reviewing published English articles and our case, it was suggested that the pathogenesis of SLE is implicated in the development of moyamoya vasculopathy leading to cerebrovascular events. Moreover, pregnancy may affect the bleeding from the fragile collateral vessel wall.

Moyamoya disease (MMD) is a rare, chronic and progressive cerebrovascular disorder that is characterised by stenosis and occlusion of the distal carotid, proximal middle and anterior cerebral arteries and is...

Moyamoya disease in adults is a chronic, progressive disorder characterized by fine collateral vessel networks in the brain. The disorder can lead to negative mood and stress, which, left unresolved, may increase adverse health outcomes. We conducted a cross-sectional survey to examine stress and mood of adults with moyamoya disease. Participants were recruited at a university hospital in Seoul, Korea. Data were collected through questionnaires and review of participants' electronic medical records. A total of 109 adults participated. Significant correlations were found between perceived stress, anxiety, and depression. Adults with moyamoya disease experience anxiety, depression, and stress related to the risk of cerebral hemorrhage or ischemia, similar to those with other cerebrovascular disease. If negative mood and stress were uncontrolled, those can cuase adverse health outcomes. Health professionals caring for people with moyamoya disease should carefully observe their stress and mood and develop interventions tailored to stages of disease to help them manage. The study results provide baseline information for understanding the level of, and the factors associated with, stress and mood.

Introduction: Sox17 promotes endothelial migration by destabilizing endothelial adherens junctions, rearranging cytoskeletal structure and upregulates expression of a number of genes preferentially expressed in angiogenic tip cells. However, the deletion of Sox17 stabilizes endothelial junctions and decreased proliferation, vice versa. The AVM after endothelial Alk1 deletion shows uncontrolled endothelial proliferation and cytoskeletal misarrangement. Therefore, we hypothesized that deletion of Sox17 in endothelial cells are sufficient to ameliorate brain AVM via Notch pathway modulation. Methods: Alk1 2f/2f Sox17 2f/2f double transgenic mice (Alk1 exons 4-6 flanked by loxP sites) were bred with VEcad-iCreER T2 mice that express tamoxifen-inducible cre re-combinase (iCreER) in EC. EC-Alk1 and Sox17 deletion was induced by intraperitoneal injection of tamoxifen (25mg/kg, Sigma-Aldrich) with interval of 3 days. The spatiotemporal changes of blood vessel were investigated in Alk1 deletion alone and Alk1-Sox17 co-deletion mice. Vascular morphology was analyzed 9 days after tamoxifen administration. The transcripts (mRNA) and protein expression of target molecules of Notch pathway (Dll4, Hey1, Hey2, NIICD) were also evaluated. Results: The dysplastic blood vessel index of solitary Alk1 2f/2f deletion mice was higher than Alk1 2f/2f -Sox17 2f/2f double transgenic mice (P&lt;0.001) and was similar to human AVM. Dysplasia in Alk1 2f/2f mice was partially rescued by Sox17 co-deletion in morphologically. In addition, target molecules of Notch pathway, Dll4, Hey1, Hey2, Jag1 was increased in Alk1-Sox17 co-deletion mice rather than solitary Alk1 deletion mice. Conclusions: Collectively, our findings demonstrate that the modulation of Sox17 could restrict the Alk1-induced AVM by upregulation of Notch pathway. This work establishes the Notch-Sox17 axis as a novel regulatory mechanism underlying Notch-mediated vascular stabilization in brain AVM.

BackgroundNon-targeting effects of radiotherapy have become as clinical concern due to secondary tumorigenesis in the patients receiving radiotherapy. Radiotherapy also affects non-tumoral cells present in the tumor microenvironment and surrounding tissues. As such, the irradiated cells are thought to communicate the signals that promote secondary tumorigenesis by affecting the function and fate of non-irradiated cells in the vicinity including endothelial cells. This may include up-regulation of genes in irradiated cells, secretion of paracrine factors and induction of gene expression in surrounding non-irradiated cells, which favor cell survival and secondary tumorigenesis. In the current study, we aimed to investigate whether the conditioned media from X-ray irradiated MCF-7 cells contribute to induction of gene expression in human umbilical vein endothelial cells (HUVECs) in vitro and modulate their angiogenic capability and migration.MethodsFollowing the co-culturing of X-ray irradiated MCF-7 media with HUVECs, the migration and wound healing rate of HUVECs was monitored using Transwell plate and scratch wound healing assay, respectively. The levels of angiogenic protein i.e. vascular endothelial growth factor (VEGF-A) in the conditioned media of MCF-7 cells was measured using ELISA. Additionally, we quantified mRNA levels of VEGFR-2, HSP-70, Ang-2, and Ang-1 genes in HUVECs by real time-PCR. Tubulogenesis capacity of endothelial cells was measured by growth factor reduced Matrigel matrix, whereas expression of CD34 (a marker of angiogenic tip cells) was detected by flow cytometry.ResultsData showed that VEGF-A protein content of conditioned media of irradiated MCF-7 cells was increased (P < 0.05) with increase in dose. Data showed that irradiated conditioned media from MCF-7 cells, when incubated with HUVECs, significantly enhanced the cell migration and wound healing rate of HUVECs in a dose-dependent manner (P < 0.05). The mRNA levels of VEGFR-2, HSP-70, Ang-2, and Ang-1 were dose-dependently enhanced in HUVECs incubated with irradiated conditioned media (P < 0.05). Importantly, HUVECs treated with irradiated conditioned media showed a marked increase in the tube formation capability as well as in expression of CD34 marker (P < 0.05).ConclusionsOur findings indicate that conditioned media from irradiated MCF-7 cells induce angiogenic responses in endothelial cells in vitro, which could be due to transfer of overexpressed VEGF-A and possibly other factors secreted from irradiated MCF-7 cells to endothelial cells, and induction of intrinsic genes (VEGFR-2, HSP-70, Ang-2, and Ang-1) in endothelial cells.2jWTXz4D4cK47Ck7iekukBVideo abstract.Graphical abstract

Nutcracker Syndrome—How Well Do We Know It?

Role of tumor vascular architecture in drug delivery

The renal vasculature consists of highly specialized blood vessels with distinct physiological functions. Defining their transcriptional signatures and tracing their developmental ontogeny has thus far been challenging due to a lack of regionally specific endothelial biomarkers. Here, we performed single nuclear RNA sequencing (snucRNA-Seq) to interrogate the transcriptional heterogeneity of embryonic renal endothelial cells (ECs). We identified ten endothelial subtypes, and validated regionally restricted expression of novel marker genes of glomeruli, arteries, vasa recta, and immature capillary subtypes using multiplex RNAscope. We also define previously uncharacterized and heterogeneous molecular signatures of the immature renal vasculature, including putative endothelial progenitors. We interrogate biological characteristics of immature EC types using a variety of in vivo tools. Lineage tracing of Esm1-expressing cells reveals the previously unrecognized multi-origin and multi-clonal endothelial tip cell contribution to the glomerular vasculature. Together, this study provides a validated, tool-focused developmental atlas of the murine renal vasculature and elucidates novel cellular mechanisms of nephron vascularization.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10456-025-10000-0.

The advent of flow dynamics and the recent availability of perfusion analysis software have provided new diagnostic tools and management possibilities for cerebrovascular patients. To this end, we provide an example of the use of color-coded angiography and its application in a rare case of a patient with a pure middle cerebral artery (MCA) malformation. A 42-year-old male chronic smoker was evaluated in the emergency room due to sudden onset of severe headache, nausea, vomiting and left-sided weakness. Head computed tomography revealed a right basal ganglia hemorrhage. Cerebral digital subtraction angiography (DSA) showed a right middle cerebral artery malformation consisting of convoluted and ectatic collateral vessels supplying the distal middle cerebral artery territory-M1 proximally occluded. An associated medial lenticulostriate artery aneurysm was found. Brain single-photon emission computed tomography with and without acetazolamide failed to show problems in vascular reserve that would indicate the need for flow augmentation. Twelve months after discharge, the patient recovered from the left-sided weakness and did not present any similar events. A follow-up DSA and perfusion study using color-coded perfusion analysis showed perforator aneurysm resolution and adequate, albeit delayed perfusion in the involved vascular territory. We propose a combined congenital and acquired mechanism involving M1 occlusion with secondary dysplastic changes in collateral supply to the distal MCA territory. Angiographic and cerebral perfusion work-up was used to exclude the need for flow augmentation. Nevertheless, the natural course of this lesion remains unclear and long-term follow-up is warranted.

BackgroundCoronary collateral arteries function as natural bypasses in the event of coronary obstruction. The degree of collateral network development significantly impacts the outcome of patients after an acute myocardial infarction (AMI). MicroRNAs (miRNAs, miRs) have arisen as biomarkers to identify heterogeneous patients, as well as new therapeutic targets in cardiovascular disease. We sought to identify miRNAs that are differentially expressed in chronic total occlusion (CTO) patients with well or poorly developed collateral arteries.Methods and ResultsForty-one CTO patients undergoing coronary angiography and invasive assessment of their coronary collateralization were dichotomized based on their collateral flow index (CFI). After miRNA profiling was conducted on aortic plasma, four miRNAs were selected for validation by real-time quantitative reverse transcription polymerase chain reaction in patients with low (CFI<0.39) and high (CFI>0.39) collateral artery capacity. We confirmed significantly elevated levels of miR423-5p (p<0.05), miR10b (p<0.05), miR30d (p<0.05) and miR126 (p<0.001) in patients with insufficient collateral network development. We further demonstrated that each of these miRNAs could serve as circulating biomarkers to discriminate patients with low collateral capacity (p<0.01 for each miRNA). We also determined significantly greater expression of miR30d (p<0.05) and miR126 (p<0.001) in CTO patients relative to healthy controls.ConclusionThe present study identifies differentially expressed miRNAs in patients with high versus low coronary collateral capacity. We have shown that these miRNAs can function as circulating biomarkers to discriminate between patients with insufficient or sufficient collateralization. This is the first study to identify miRNAs linked to coronary collateral vessel function in humans.