bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanistic Investigation of Reversal of Endothelial Dysfunction in hyperglycemia
Authors: Patel Hemang , Chen Juan , Kavdia Mahendra 
Published: November 2023

Progression of endothelial dysfunction has emerged as a significant risk factor for diabetes related complications such as retinopathy, nephropathy, neuropathy and vascular dementia. At elemental level, endothelial dysfunction results from and into disproportionate changes in vasoactive reactive oxygen species (ROS). Superoxide (O2−), nitric oxide (NO) and hydrogen peroxide (H2O2) regulates the redox state of dysfunctional endothelium. Increased O2− levels rapidly react away with NO to reduce its bioavailability, which sets the stage for endothelial dysfunction in hyperglycemia. Simultaneous regulation in H2O2 levels supports either vasoconstrictive or vasorelaxative processes. Several therapeutic strategies had limited success to manage endothelial dysfunction and results from these strategies have shown a lack of understanding of the redox interplay. We studied the regulation of overall redox state and endothelial function during hyperglycemia. We measured O2−, NO, and H2O2 levels using dihydroethidium (DHE), DAF‐FM diacetate and Amplex Red assay, respectively, during sodium nitrite (NaNO2), superoxide dismutase (SOD) and catalase treatments in hyperglycemia treated HUVECs. Hyperglycemia significantly increased O2− and H2O2 levels and decreased NO levels in HUVECs. Treatments to exogenous SOD and NaNO2 decreased O2− levels and significantly increased NO levels in hyperglycemic‐HUVECs. Similarly, treatment with catalase also induced similar changes in O2− and NO levels. Our results suggest that besides the O2− and NO, regulation of H2O2 levels also serves a viable therapeutic alternative for improving the redox state of hyperglycemic‐HUVECs. These results also suggest that production of NO, O2− and H2O2 is tightly regulated in hyperglycemia‐induced endothelial dysfunction. The indirect manipulation of the fate of O2− may hold a key to reverse and manage the hyperglycemic‐endothelial dysfunction.Support or Funding InformationThis study was funded by NIHR01 HL084337
MICROVASCULAR FUNCTION IS IMPAIRED IN ADULTS WHO REPORTED ADVERSE CHILDHOOD EVENTS
Authors: Miguelez Paula Rodriguez , Thomas Jeffrey , Seigler Nichole , Pollock Jennifer S , Harris Ryan A 
Published: November 2023

INTRODUCTIONMicrovascular function, assessed using the cutaneous microcirculation, has been proposed as a prognostic marker of cardiovascular diseases (CVDs). Adversity early in life, referred to as adverse childhood events (ACEs), has been associated with the development of CVDs during adulthood. Whether or not microvascular dysfunction is present in adults who report ACEs has yet to be investigated.PURPOSEThis study sought to test the hypothesis that microvascular function is lower in adults who reported ACEs compared to adults who did not.METHODSNineteen young adults (33 ± 2 yrs), with no evidence of overt CVDs, were separated into two groups based on their self‐reported ACE study questionnaire score; HiA: ACE score ≥ 4 (n=9) or NoA: ACE score = 0 (n=10). Augmentation index at 75 bpm (AIx75) was determined by applanation tonometry (SphygmoCor) as an independent predictor of CVD risk. Laser Doppler flowmetry (MoorVMS‐LDF) was used to evaluate microvascular function non‐invasively through the assessment of cutaneous flux (expressed as a perfusion unit (PU)) during baseline (BL), post‐occlusive reactive hyperemia (PORH), local thermal hyperemia (Ht), and iontophoresis of acetylcholine (Ach).RESULTSNo differences in BL cutaneous flux were observed between groups (HiA: 12.1 ± 15.4 vs. NoA: 7.6 ± 4.8 PU), p=0.387). The PORH response was significantly lower (p=0.039) in HiA (25.1 ± 9.7 PU) compared with NoA (37.0 ± 13.1 PU). Additionally, endothelium‐dependent vasodilation, assessed by the iontophoresis of Ach peak flux relative to maximal Ht flux was significantly lower (p=0.009) in HiA compared to NoA (64 ± 24 vs. 119 ± 52 %, respectively). Further, strong correlations were identified between maximal Ach response and AIx75 (r=−0.475; p=0.040) and between ACE score and both PORH (r=−0.430; p=0.066) and maximal Ach response (r=−0.501: p=0.029).CONCLUSIONFor the first time, we have documented an impaired microvascular response and a reduced endothelium‐dependent cutaneous vasodilation in adults who have reported ACEs compared with adults who did not report any ACE. These findings suggest that the contribution of ACEs to CVDs later in life may be through a reduction in microvascular function.Support or Funding InformationSupport in part by NIH/NHLBI P01HL06999.
The Role of Pericytes for Angiogenesis in Skeletal Muscle Tissue
Authors: Hoier Birgitte , Hellsten Ylva 
Published: November 2023

We and others have previously shown that pericytes are invested on most capillaries in skeletal muscle but the physiological role of pericytes in this tissue remains unclear. The aim of the present study was to elucidate whether pericytes contribute to angiogenesis in skeletal muscle by secretion of VEGF and promotion of endothelial cell proliferation.Pericytes, endothelial cells and skeletal muscle cells were isolated from rat skeletal muscle tissue by use of Dynabeads coupled to specific antibodies and the cells were either characterized for the expression of angiogenic factors or maintained in culture for experiments. Pericytes were found to contain a number of angiogenic factors, e.g. Vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor receptor‐2 (VEGFR‐2), Thrombospondin‐1 (TSP‐1), Angiopoietin 1 and 2, (Ang 1 and 2) and platelet‐derived growth factor receptor beta (PDGFR‐β). The expression of VEGF, VEGFR‐2, eNOS, and PDGFR‐β was higher in pericytes conditioned with skeletal muscle media. The muscle conditioned pericytes also released a 7‐fold greater amount of VEGF to the media than untreated control cells. Endothelial cells conditioned with media from pericytes, that first had been conditioned by muscle media, showed an improved rate of proliferation compared to non‐conditioned endothelial cells. Experiments with VEGF neutralizing antibodies added to the conditioned media suggested that VEGF was not responsible for the increased proliferation of endothelial cells.In conclusion, we have identified a complex pattern of cellular communication in cultures of pericytes, endothelial and skeletal muscle cells whereby skeletal muscle cells activate pericytes and induce an upregulation of several angiogenic factors including VEGF. The activated pericytes release VEGF and other proangiogenic compounds and thereby induce proliferation of endothelial cells and capillary growth. The study strongly suggests that pericytes are important in capillary growth.Support or Funding InformationThe study was supported by The Danish Council for Independent Research‐ Medical Sciences.
Sigma‐1 Receptor Agonists Compromise Barrier Function of Endothelial Cell Monolayers with Differential Impact on Cells Derived from Cardiac or Dermal Microcirculation and Dermal Lymphatics
Authors: Schecker Caitlin , Adderley Shaquria , Breslin Jerome W 
Published: November 2023

Sigma‐1 receptors are chaperone proteins in the endoplasmic reticulum known to modulate calcium signaling through the IP3 receptor. We recently demonstrated the presence of these receptors in the lymphatic vessels. In the current study we tested the hypothesis that Sigma‐1 receptors are present and functional in human cardiac microvascular endothelial cells (HCMEC), dermal microvascular endothelial cells (HDMEC) and human dermal lymphatic endothelial cells (HDLEC). Western blotting and immunofluorescence labeling were performed to verify expression of the Sigma‐1 receptor in these cell types. The cells were treated with the selective sigma‐1 receptor agonist, afobazole, or dehydroepiandrosterone (DHEA), which also can activate sigma‐1 receptors. Transendothelial electrical resistance (TER) was used as an index of barrier function. Western blot analysis confirmed expression of the Sigma‐1 receptor in HCMEC, HDMEC, and HDLEC. Immunofluorescence confocal microscopy studies showed that Sigma‐1 localization was largely punctate and perinuclear, with a similar pattern seen for endoplasmic reticulum. In HCMEC or HDLEC, DHEA and afobazole both decreased TER. However, in HDMEC, neither agonist caused a significant decrease in barrier function. The data demonstrates that Sigma‐1 receptors are indeed present in HCEC, HDEC and ADLEC, but functional responses to Sigma‐1 receptor agonists vary between the different endothelial cell sources.Support or Funding InformationSupported by NIH grant R01HL098215 and APS Frontiers Fellowship.
Sphingosine‐1‐phosphate and 8‐pCPT‐2′‐O‐Me‐cAMP Can Restore Alcohol‐induced Junctional Disorganization and Barrier Dysfunction of Human Brain Microvascular Endothelial Cells
Authors: Alves Natascha Guimaraes , Adderley Shaquria , Yuan Sarah , Breslin Jerome 
Published: November 2023

The blood‐brain‐barrier (BBB) is a highly selective endothelial barrier that protects the brain from blood‐born cytotoxins and ensures proper homeostasis of the central nervous system. Alcohol has previously been shown to compromise the BBB, however the mechanisms involved are incompletely understood. We hypothesized that alcohol increases BBB permeability by activating the p38 MAP kinase, disrupting paracellular junction proteins, such as VE‐Cadherin and Claudin‐5, and that microvascular barrier stabilizers such as sphingosine‐1‐phosphate (S1P) and 8‐pCPT‐2′‐O‐Me‐cAMP (8‐CPT) can resolve alcohol‐induced BBB dysfunction. Cultured primary human brain microvascular endothelial cell (HBMEC) monolayers were used to model BBB function so that endothelial‐specific mechanisms could be studied. Trans‐endothelial electrical resistance (TER) was used as an index of barrier function. Localization of VE‐cadherin and Claudin‐5 was determined by immunofluorescence microscopy. S1P (1 μM) or 8‐CPT (100 μM) were applied following treatment with alcohol to test their efficacies to rescue barrier function. The results show that treatment of HBMEC with alcohol (50–100 mM) causes a biphasic hyperpermeability response, characterized by an initial transient decrease in TER (10 min) that recovers, followed by a prolonged decrease in TER that lasts several hours. Surprisingly, we observed that pretreatment with the selective p38 MAPK inhibitor SB208530 (20 μM) does not block the alcohol‐induced decrease in HBMEC monolayer TER. Predictably, treatment of HBMEC monolayers with either S1P or 8‐CPT significantly enhances barrier function. However, pretreatment with S1P or 8‐CPT does not prevent the disruption caused by 75 mM alcohol, and S1P pretreatment can even exacerbate the alcohol‐induced decrease in TER. In contrast, application of S1P or 8‐CPT, after alcohol has already evoked a decrease in TER, causes a hastened recovery to normal HBMEC monolayer barrier function. Our Immunocytochemistry studies demonstrate colocalization of VE‐Cadherin and Claudin‐5 at intercellular junctions, and alcohol disrupts this organization. Importantly, treatment with S1P (after alcohol) can restore junctional integrity. Taken together, our results show that alcohol causes a biphasic decrease in HBMEC monolayer barrier function that does not require p38 MAP kinase activation, but does involve reorganization of junctional protein complexes. In addition, S1P and 8‐CPT can enhance barrier function and may be useful for restoring BBB function in the presence of alcohol intoxication.Support or Funding InformationSupported by a grant from the USF MCOM Office of Research.
Mitigation of nitrosative stress and inflammation by Vitamin C in cardiomyopathy
Authors: Akolkar Gauri , Bagchi Ashim K , da Silva Dias Danielle , de Angelis Katia , Jassal Davinder , Singal Pawan K 
Published: November 2023

BackgroundOxidative/nitrosative stress is being linked as a key event in development of various cardiovascular diseases. Increase in the generation of reactive oxygen and nitrogen species is considered as a major trigger for cellular and tissue injury in the heart leading to myocardial dysfunction in general and doxorubicin (Dox) ‐ induced heart failure in particular. Previously we have shown that Vitamin C (Vit C), a very potent antioxidant, reduced Dox‐induced oxidative stress in isolated cardiomyocytes. However the role of Vit C in mitigation of cardiac nitrosative stress and inflammation needs to be understood. The aim of present study is to understand role of Vit C on cardiac nitrosative stress and inflammation.MethodsCardiomyocytes isolated from adult Sprague‐Dawley rats were treated with predetermined doses of Vit C (25 μM), Dox (10 μM) or Vit C (25 μM) + Dox (10 μM) for in vitro studies. To understand the effect of Vit C in vivo, adult male Wistar rats were treated with Vit C (50 mg/kg bw orally daily) for 6 weeks or Dox (15mg/kg bw given intraperitoneally in six equal doses for three weeks) or combination treatment with Vit C + Dox. At the end of 6 weeks, animals were euthanized and hearts and blood were collected for further analysis.ResultsDox treatment increased levels of peroxynitrite in isolated cardiomyocytes and this effect was significantly reduced by Vit C co‐treatment. Both invitro and invivo, Dox induced an increase in levels of Nitric oxide, Nitric oxide synthase (NOS) activity and protein nitrosylation. These in vitro and invivo effects were blocked by Vit C. Dox caused an increased protein expression of inducible NOS which was prevented by Vit C, whereas expression of endothelial NOS was reduced. Treatment with Dox showed increase in levels of inflammatory cytokine TNFα and a decrease in the anti‐inflammatory cytokine IL10. Vit C co‐treatment prevented deleterious effects of Dox by reduction in levels of TNFα and increased levels of IL10.ConclusionBased on these results, it is suggested that an attenuation of major triggers of Dox‐induced cardiotoxicity by Vit C would be beneficial in protecting the heart from cardiac side effect of chemotherapy.Support or Funding InformationCIHR and GETS, University of Manitoba.
Pharmacological Inhibition of NAD(P)H Oxidase with the Peptide gp91ds‐tat During Ischemic Stroke Reduces Infarct Volume and Improves Vascular Reactivity in Obese Zucker Rats
Authors: Brooks Steven D , Branyan Kayla , Asano Shinichi , Hu Hang , Ren Xuefang , Brock Robert W , Frisbee Jefferson C , Chantler Paul D 
Published: November 2023

Production of reactive oxygen species (ROS) during ischemic stroke and subsequent reperfusion has been linked to increased infarct size and poor outcomes in multiple rodent models. NAD(P)H) oxidase (NOX) has been identified as a principal source of ROS generation during ischemia/reperfusion, and inhibition of NOX during ischemic stroke results in decreased infarct size and improved outcomes in preclinical models, although underlying mechanisms are unclear. Elevated blood glucose increases ROS production by NOX during ischemia/reperfusion, and vascular dysfunction can impair collateral flow; a stroke model that incorporates hyperglycemia and vascular dysfunction may therefore amplify ROS production and lead to larger infarcts and worsened outcomes. As such, the aim of this study was to determine the effects of gp91ds‐tat, a peptide inhibitor of NOX‐2, on infarct size and vascular reactivity in both the ipsilateral (IL) and contralateral (CL) middle cerebral arteries (MCAs) of lean and obese Zucker rats (LZR, OZR) two weeks after ischemic stroke. Strokes were induced in 17 week old rats for 60 min by transient MCA occlusion (tMCAO); 30 minutes into tMCAO, OZR received either gp91ds‐tat (10mg/kg body weight) or vehicle. Changes in cerebral blood flow were monitored by laser Doppler. 15 days after tMCAO, animals were sacrificed and the IL and CL MCAs were isolated and cannulated in an ex vivo microvessel preparation; MCA reactivity was assessed in response to acetylcholine (ACh). Infarct size was measured by TTC stain. Infarct size and mortality rates were increased at 15 days post‐tMCAO in control treated OZR vs. LZR. Vascular dysfunction was worsened in both CL and IL MCA; ACh‐induced vasodilation was reduced 35% in CL‐MCA compared to non‐stroke OZR MCA, while in IL‐MCA, dilation was completely ablated, likely due to reperfusion injury. In contrast, OZR treated with gp91ds‐tat demonstrated reduced infarct size and mortality, as well as improved recovery of cerebral blood flow after reperfusion vs. control OZR. Vascular reactivity improved significantly, as ACh‐induced dilation in CL‐MCA and IL‐MCA increased 12% and 67% respectively vs. control treated OZR, indicating gp91ds‐tat acutely reduced damage from reperfusion injury. Our findings suggest that preexisting metabolic syndrome can worsen neurological and cerebrovascular outcomes following ischemic stroke though a mechanism at least partially mediated by NOX. Targeted inhibition of NOX during ischemia/reperfusion may improve stroke outcomes, especially in patients with history of metabolic syndrome, and warrants further consideration as a treatment avenue for ischemic stroke.Support or Funding InformationNIH COBRE GrantAHA Predoctoral Fellowship
Treatment with the Mitochondrial‐targeted Antioxidant Peptide SS‐31 Improves Cerebromicrovascular Function in Aged Mice
Authors: Tarantini Stefano , Hertelendy Peter , Valcarcel‐Ares Marta Noa , Gautam Tripti , Tucsek Zsuzsanna , Csiszar Anna , Ungvari Zoltan 
Published: November 2023

Moment‐to‐moment adjustment of cerebral blood flow (CBF) via neurovascular coupling has a critical role in maintenance of healthy cognitive function. In advanced age increased oxidative stress and cerebromicrovascular endothelial dysfunction impair neurovascular coupling, likely contributing to age‐related decline of higher cortical functions. There is increasing evidence showing that mitochondrial oxidative stress plays a critical role in a range of age‐related cellular impairments, but its role in neurovascular uncoupling remains unexplored. The present study was designed to test the hypothesis that attenuation of mitochondrial oxidative stress may exert beneficial effects on neurovascular coupling in aging. To test this hypothesis 24 month old C57BL/6 mice were treated with a cell permeable, mitochondria‐targeted antioxidant peptide (SS‐31; 10 mg/kg/day, s.c.) or vehicle for 2 weeks. Neurovascular coupling was assessed by measuring CBF responses (laser Doppler flowmetry) and evoked field potentials in the somatosensory cortex evoked by contralateral electric whisker pad stimulation. We found that neurovascular coupling responses and ATP‐induced endothelium‐dependent CBF responses were significantly impaired in aged mice. Treatment with SS‐31 significantly improved neurovascular coupling responses, at least in part, by increasing NO‐mediated cerebromicrovascular dilation. These findings are paralleled by the protective effects of SS‐31 on mitochondrial production of reactive oxygen species in cultured cerebromicrovascular endothelial cells derived from aged animals. Thus, mitochondrial oxidative stress contributes to age‐related cerebromicovascular dysfunction. We propose that the antioxidant peptide SS‐31 should be considered for pharmacological microvascular protection for the prevention/treatments of age‐related diseases of the CNS.Support or Funding InformationThis work was supported by grants from the American Heart Association and the National Institute on Aging.
Critical role of telomerase in regulating cerebral vascular function and redox environment
Authors: Ait‐Aissa Karima , Hockenberry Joseph , Gutterman David D , Geurts Aron , Beyer Andreas M 
Published: November 2023

RationaleCerebrovascular dysfunction has been directly been linked to cerebral micro bleeds and cognitive decline in clinical settings and rodent models of stroke and dementias. Recent clinical studies suggest that oxidative stress may facilitate the development and progression of impaired Flow‐mediated dilation (FMD) in patients with cerebrovascular disease. FMD is the most physiological relevant form of endothelial‐mediated vasodilation. Our laboratory has previously shown that telomerase, a ribo‐nucleoprotein that counteracts telomere shortening, has a protective effect on endothelial function under conditions of oxidative stress in the human microcirculation. For example, in the presence of coronary artery disease, decreased telomerase activity contributes to a shift in the mediator of FMD from atheroprotective nitric oxide (NO) to pro‐inflammatory and atherogenic hydrogen peroxide (H2O2). Endothelial dysfunction in the cerebral vasculature has been directly linked to cerebral microbleeds and cognitive decline in models of stroke and dementia, thus we hypothesized that TERT plays a critical role in maintaining normal NO‐mediated vasodilation in the cerebral vasculature.MethodsUsing Crisp/Cas9 we generated a novel deletion model for TERT (the catalytic subunit of telomerase) in rats on the WKY background. Middle cerebral arteries (MCA) were isolated from wild type (WT) and TERT−/− rats, prepared for videomicroscopy, and FMD was measured. The mediator of FMD was determined using a pharmacological inhibitor of NO synthase (L‐NAME) and a scavenger of H2O2 (PEG‐catalase).ResultsNo changes in the magnitude of FMD were observed in MCA from TERT−/− compared to WT rats (max dilation: TERT−/− 71.97±14.7% vs. WT 80.9±10.6%; n≥3). In WT animals, pre‐incubation with L‐NAME abolished FMD while PEG‐catalase had no effect on FMD (max dilation: L‐NAME −5.8±7%*; Peg‐catalase 76.6±8.6%; n≥3; p<0.05). Conversely, in TERT−/− animals FMD was not affected in the presence of L‐NAME but abolished in presence of Peg‐catalase (max dilation: L‐NAME 57.8.0±16.5%; Peg‐catalase −4.3±2.4*%; n≥3; p>0.05 two way ANOVA RM).ConclusionsTelomerase deficiency causes a switch in the vasoactive mediator of FMD from NO to H2O2, creating a pro‐oxidative environment in the cerebral vasculature. Understanding the regulatory role of telomerase in mediating this mechanistic switch may provide a novel therapeutic strategy for the treatment or prevention of cerebrovascular dysfunction.Support or Funding InformationR01 HL113612/R21 OD018306