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Marfan syndrome is a connective tissue disorder that affects multiple organs, with the most serious complications occurring in the cardiovascular system. Aortic root dilatation and dissection are particularly concerning. While the prevalence of Marfan syndrome is equal between genders, male patients have a higher risk of developing thoracic aortic aneurysm and dissection compared to females. A recent study using a mouse model of severe Marfan syndrome found that male mice had poorer survival rates and exhibited lower elastin content and more fragmented elastic fibers compared to female mice. The study suggests that material properties, aortic size, and wall integrity may be connected to dissection risk. Further research is needed to understand how age and sex contribute to dissection risk in Marfan syndrome. [Extracted from the article]

Background: In many countries, nitrous oxide is used in a gas mixture (EMONO) for short-term analgesia. Cases of addiction, with significant misuse, have been reported in hospitalized patients. Patients suffering from sickle cell disease (SCD) could represent a high-risk population for substance use disorder (SUD) due to their significant pain crisis and repeated use of EMONO. The objective of the PHEDRE study was to assess the prevalence of SUD for EMONO in French SCD patients. Results: A total of 993 patients were included. Among 339 EMONO consumers, only 38 (11%) had a SUD, with very few criteria, corresponding mainly to a mild SUD due to a use higher than expected (in quantity or duration) and relational tensions with the care teams. Almost all patients (99.7%) were looking for an analgesic effect, but 68% of patients were also looking for other effects. The independent risks factors associated with at least one SUD criterion were: the feeling of effects different from the expected therapeutic effects of EMONO, at least one hospitalization for vaso occlusive crisis in the past 12 months and the presence of a SUD for at least one other analgesic drug. Conclusions: The use of EMONO was not problematic for the majority of patients. Manifestations of SUD that led to tensions with healthcare teams should alert and lead to an evaluation, to distinguish a true addiction from a pseudoaddiction which may be linked to an insufficient analgesic treatment related to an underestimation of pain in SCD patients. Trial registration: Clinical Trials, NCT02580565. Registered 16 October 2015, https://clinicaltrials.gov/ [ABSTRACT FROM AUTHOR]

Background: Panx1 (pannexin 1) forms high conductance channels that secrete ATP upon stimulation. The role of Panx1 in mediating constriction in response to direct sympathetic nerve stimulation is not known. Additionally, it is unknown how the expression level of Panx1 in smooth muscle cells (SMCs) influences α-adrenergic responses. We hypothesized that the amount of Panx1 in SMCs dictates the levels of sympathetic constriction and blood pressure.Methods: To test this hypothesis, we used genetically modified mouse models enabling expression of Panx1 in vascular cells to be varied. Electrical field stimulation on isolated arteries and blood pressure were assessed.Results: Genetic deletion of SMC Panx1 prevented constriction by electric field stimulation of sympathetic nerves. Conversely, overexpression of Panx1 in SMCs using a ROSA26 transgenic model increased sympathetic nerve-mediated constriction. Cx43 hemichannel inhibitors did not alter constriction. Next, we evaluated the effects of altered SMC Panx1 expression on blood pressure. To do this, we created mice combining a global Panx1 deletion, with ROSA26-Panx1 under the control of an inducible SMC specific Cre (Myh11). This resulted in mice that could express only human Panx1, only in SMCs. After tamoxifen, these mice had increased blood pressure that was acutely decreased by the Panx1 inhibitor spironolactone. Control mice genetically devoid of Panx1 did not respond to spironolactone.Conclusions: These data suggest Panx1 in SMCs could regulate the extent of sympathetic nerve constriction and blood pressure. The results also show the feasibility humanized Panx1-mouse models to test pharmacological candidates. [ABSTRACT FROM AUTHOR]

Pericytes are essential components of small blood vessels and are found in human aortic vasa vasorum. Prior work uncovered lower vasa vasorum density and decreased levels of pro‐angiogenic growth factors in adventitial specimens of human ascending thoracic aortic aneurysm. We hypothesized that adventitial extracellular matrix (ECM) from normal aorta promotes pericyte function by increasing pericyte contractile function through mechanisms deficient in ECM derived from aneurysmal aortic adventitia. ECM biomaterials were prepared as lyophilized particulates from decellularized adventitial specimens of human and porcine aorta. Immortalized human aortic adventitia‐derived pericytes were cultured within Type I collagen gels in the presence or absence of human or porcine adventitial ECMs. Cell contractility index was quantified by measuring the gel area immediately following gelation and after 48 h of culture. Normal human and porcine adventitial ECM increased contractility of pericytes when compared with pericytes cultured in absence of adventitial ECM. In contrast, aneurysm‐derived human adventitial ECM failed to promote pericyte contractility. Pharmacological inhibition of TGFβR1 and antibody blockade of α2β1 integrin independently decreased porcine adventitial ECM‐induced pericyte contractility. By increasing pericyte contractility, adventitial ECM may improve microvascular function and thus represents a candidate biomaterial for less invasive and preventative treatment of human ascending aortic disease. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES We hypothesized that expression and activity of nitric oxide synthase-3 enzyme (Nos3) in bicuspid aortic valve (BAV) aortopathy are related to tissue layer and Nos3 genotype. METHODS Gene expression of Nos3 and platelet and endothelial cell adhesion molecule-1 (Pecam1) and NOS activity were measured in intima-containing media and adventitial specimens of ascending aortic tissue. The presence of 2 Nos3 single-nucleotide polymorphisms (SNPs; −786T/C and 894G/T) was determined for non-aneurysmal (NA) and aneurysmal patients with BAV (n  = 40, 89, respectively); patients with tricuspid aortic valve (TAV) and aneurysm (n  = 151); and NA patients with TAV (n  = 100). RESULTS Elevated Nos3 relative to Pecam1 and reduced Pecam1 relative to a housekeeping gene were observed within intima-containing aortic specimens from BAV patients when compared with TAV patients. Lower Nos3 in the adventitia of aneurysmal specimens was noted when compared with specimens of NA aorta, independent of valve morphology. NOS activity was similar among cohorts in media/intima and decreased in the diseased adventitia, relative to control patients. Aneurysmal BAV patients exhibited an under-representation of the wild-type genotype for −786 SNP. No differences in genotype distribution were noted for 894 SNP. Primary intimal endothelial cells from patients with at least 1 C allele at −786 SNP exhibited lower Nos3 when compared with wild-type cells. CONCLUSIONS These findings of differential Nos3 in media/intima versus adventitia depending on valve morphology or aneurysm reveal new information regarding aneurysmal pathophysiology and support our ongoing assertion that there are distinct mechanisms giving rise to ascending aortopathy in BAV and TAV patients. [ABSTRACT FROM AUTHOR]

Inflammation and oxidative stress play a key role in the pathophysiology of sickle cell disease (SCD). However, the potential influence of different sickle genotypes, or hydroxyurea (HU) treatment, on these factors remains poorly documented. The present study compared several plasma markers of inflammation and oxidative stress, as well as microvascular function, between patients with sickle SC disease (HbSC, n = 19) and patients with sickle cell anemia (HbSS) under hydroxyurea (HU) treatment (n = 16), or not (n = 13). Hemorheological parameters and levels of inflammatory (IL‐6, IL‐8, IFN‐γ, MCP‐1, MIP‐1β, TNF‐α) and oxidative stress (AOPP, MDA, MPO) markers were determined. Peripheral microcirculatory cutaneous blood flow and immediate microvascular response to local heat were evaluated using laser Doppler flowmetry. Oxidative stress and inflammation were lower in HbSC patients and HbSS patients under HU therapy compared to HbSS patients not treated with HU. Blood viscosity was higher in HbSC than in HbSS patients treated with or not with HU. Vasodilation response of the cutaneous microcirculation to heat stress was higher in HbSS patients receiving HU treatment. Our results clearly established that both sickle cell genotype and HU treatment modulate inflammation and oxidative stress. [ABSTRACT FROM AUTHOR]

Background Pulmonary hypertension (PH) is characterized by arterial vascular remodelling and alteration in vascular reactivity. Since gap junctions are formed with proteins named connexins (Cx) and contribute to vasoreactivity, we investigated both expression and role of Cx in the pulmonary arterial vasoreactivity in two rat models of PH. Methods Intrapulmonary arteries (IPA) were isolated from normoxic rats (N), rats exposed to chronic hypoxia (CH) or treated with monocrotaline (MCT). RT-PCR, Western Blot and immunofluorescent labelling were used to study the Cx expression. The role of Cx in arterial reactivity was assessed by using isometric contraction and specific gap junction blockers. Contractile responses were induced by agonists already known to be involved in PH, namely serotonin, endothelin-1 and phenylephrine. Results Cx 37, 40 and 43 were expressed in all rat models and Cx43 was increased in CH rats. In IPA from N rats only, the contraction to serotonin was decreased after treatment with 37-43Gap27, a specific Cx-mimetic peptide blocker of Cx 37 and 43. The contraction to endothelin-1 was unchanged after incubation with 40Gap27 (a specific blocker of Cx 40) or 37-43Gap27 in N, CH and MCT rats. In contrast, the contraction to phenylephrine was decreased by 40Gap27 or 37-43Gap27 in CH and MCT rats. Moreover, the contractile sensitivity to high potassium solutions was increased in CH rats and this hypersensitivity was reversed following 37-43Gap27 incubation. Conclusion Altogether, Cx 37, 40 and 43 are differently expressed and involved in the vasoreactivity to various stimuli in IPA from different rat models. These data may help to understand alterations of pulmonary arterial reactivity observed in PH and to improve the development of innovative therapies according to PH aetiology.

OBJECTIVE: Our study investigated the prevalence of retinopathy and maculopathy in sickle cell patients and tested the association between these two conditions. In addition, we tested whether hematological and hemorheological parameters, as well as genotype, were involved in the development of these two conditions. METHODS: Seventy sickle cell adult patients were recruited: 37 with sickle cell anemia (SCA) and 33 with sickle cell hemoglobin C disease (SCC). All patients underwent retinal examination and macular ocular coherence tomography. Blood was sampled for the measurements of hematological and hemorheological parameters. RESULTS: Twenty-six patients had maculopathy and 30 had retinopathy with no significant difference between SCA and SCC patients. No association between the presence of retinopathy and maculopathy was detected. RBC aggregation was higher and RBC deformability lower at 3 Pa in SCA patients. Blood viscosity and hematocrit were higher in SCC than in SCA patients. However, no association was found between biological parameters and the ocular complications studied. CONCLUSIONS: Our study showed that retinopathy and maculopathy are common in sickle cell disease. Nevertheless, we found no association with hematological parameters, blood rheology or genotype. [ABSTRACT FROM AUTHOR]

Recent smooth muscle cell (SMC) lineage-tracing studies have revealed that SMCs undergo remarkable changes in phenotype during development of atherosclerosis. Of major interest, we demonstrated that Kruppel-like factor 4 (KLF4) in SMCs is detrimental for overall lesion pathogenesis, in that SMC-specific conditional knockout of the KLF4 gene (Klf4) resulted in smaller, more-stable lesions that exhibited marked reductions in the numbers of SMC-derived macrophage- and mesenchymal stem cell-like cells. However, since the clinical consequences of atherosclerosis typically occur well after our reproductive years, we sought to identify beneficial KLF4-dependent SMC functions that were likely to be evolutionarily conserved. We tested the hypothesis that KLF4-dependent SMC transitions play an important role in the tissue injury-repair process. Using SMC-specific lineage-tracing mice positive and negative for simultaneous SMC-specific conditional knockout of Klf4, we demonstrate that SMCs in the remodeling heart after ischemia-reperfusion injury (IRI) express KLF4 and transition to a KLF4-dependent macrophage-like state and a KLF4-independent myofibroblast-like state. Moreover, heart failure after IRI was exacerbated in SMC Klf4 knockout mice. Surprisingly, we observed a significant cardiac dilation in SMC Klf4 knockout mice before IRI as well as a reduction in peripheral resistance. KLF4 chromatin immunoprecipitation- sequencing analysis on mesenteric vascular beds identified potential baseline SMC KLF4 target genes in numerous pathways, including PDGF and FGF. Moreover, microvascular tissue beds in SMC Klf4 knockout mice had gaps in lineage-traced SMC coverage along the resistance arteries and exhibited increased permeability. Together, these results provide novel evidence that Klf4 has a critical maintenance role within microvascular SMCs: it is required for normal SMC function and coverage of resistance arteries. [ABSTRACT FROM AUTHOR]

Background Bicuspid aortic valve (BAV) is associated with asymmetric dilatation of the proximal ascending aorta. We previously demonstrated increased susceptibility of smooth muscle cells to oxidative stress in the BAV-aneurysmal aorta and hypothesized that antioxidant expression is regionally defined and influenced by the BAV morphotype. Methods BAV valve morphology was defined according to number of raphes: type 0 (0 raphes), type 1 (1 raphe), or type 2 (2 raphes) and by the raphe location among the left (L), right (R) or non (N) coronary cusps. Ascending aortic specimens were partitioned into three regions corresponding to the sinuses of Valsalva, denoted R, N (greater curve), and L (lesser curve). Transcripts 1, 2, and 3 from the gene expressing superoxide dismutase ( Sod ) were quantified in all three regions. Results were compared with aneurysmal and nonaneurysmal aortic specimens from patients with a tricuspid aortic valve. Results Region-specific Sod1 upregulation and Sod2 downregulation were dependent on the BAV morphotype. Sod3 was uniformly downregulated in all regions in a morphotype-independent manner. Sod1 upregulation was noted in the R region of the nonaneurysmal type 1 L/R morphotype. Aortic valve regurgitation, but not stenosis, affected the expression of Sod isoforms in specimens of degenerative aneurysms. Conclusions Region-specific transcription profiles of Sod on the basis of BAV morphotype deepen our understanding of its associated aortopathy and provide biological insight on the asymmetric dilatation pattern. This work indicates regional differences exist in the oxidative stress biology of the proximal aortic wall, and this may lead to newer diagnostic techniques to adjudicate aortic catastrophe risk. [ABSTRACT FROM AUTHOR]

Serotonin (5-HT) is a potent vasoconstrictor agonist and contributes to several vascular diseases including systemic or pulmonary hypertension and atherosclerosis. Although superoxide anion (O2•-) is commonly associated to cellular damages due to O2•- overproduction, we previously demonstrated that, in physiological conditions, O2•- also participates to the 5-HT contraction in intrapulmonary arteries (IPA). Here, we focused on the signaling pathways leading to O2•- production in response to 5-HT in rat IPA. Using electron paramagnetic resonance on rat IPA, we showed that 5-HT (100μM)-induced O2•- production was inhibited by ketanserin (1μM-an inhibitor of the 5-HT2 receptor), absence of extracellular calcium, two blockers of voltage-independent calcium permeable channels (RHC80267 50μM and LOE-908 10μM) and a blocker of the mitochondrial complex I (rotenone-100 nM). Depletion of calcium from the sarcoplasmic reticulum or nicardipine (1μM-an inhibitor of the L-type voltage-dependent calcium channel) had no effect on the 5-HT-induced O2•- production. O2•- levels were also increased by a-methyl-5-HT (10μM-a 5-HT2 receptors agonist) whereas GR127935 (1μM-an antagonist of the 5-HT 1B/D receptor) and citalopram (1μM-a 5-HT transporter inhibitor) had no effect on the 5-HT-induced O2•- production. Peroxynitrites were increased in response to 5-HT (100μM). In isolated pulmonary arterial smooth muscle cells loaded with rhod-2 or mitosox probes, we respectively showed that 5-HT increased both mitochondrial calcium and O2•- levels, which were both abrogated in absence of extracellular calcium. Mitochondrial O2•- levels were also abolished in the presence of rotenone (100 nM). In pulmonary arterial smooth muscle cells loaded with TMRM, we showed that 5-HT transiently depolarized the mitochondrial membrane whereas in the absence of extracellular calcium the mitochondrial membrane depolarisation was delayed and sustained in response to 5-HT. 5-HT decreased the mitochondrial respiratory rate measured with a Clark oxygen electrode. Altogether, in physiological conditions, 5-HT acts on 5-HT2 receptors and induces an O2•- production dependent on extracellular calcium and mitochondria. [ABSTRACT FROM AUTHOR]

Background Endothelial nitric oxide (NO) synthase (eNOS) has been implicated in the development of bicuspid aortic valve (BAV) and with differential expression in the ascending aorta of BAV patients. However, little is known about functional disruptions in the eNOS pathway and the effect on BAV-associated aortic dilatation. We tested the hypothesis that eNOS function is regionally diminished in ascending thoracic aortic aneurysms associated with BAV. Methods Thoracic aortic aneurysms specimens were collected from patients with BAV (n = 21) or tricuspid aortic valve (n = 12). Tissue samples were harvested from three circumferential regions corresponding to locations above the right, left, and noncoronary sinuses. Adventitial-stripped specimens containing media and intima only were analyzed for NO synthase 3 gene expression and total eNOS protein. Indicators of eNOS activity (pSer1177-eNOS) and NO bioavailability (phosphorylation of vasodilator-stimulated phosphoprotein at Ser239) were also measured. Results NO synthase 3 and eNOS protein were elevated in the right aortic region of BAV specimens compared with tricuspid aortic valve specimens. Activation of eNOS, as indicated by pSer1177-eNOS, was higher in BAV specimens across all regions. Despite increases in eNOS and pSer1177-eNOS, BAV specimens displayed no change in pSer239-vasodilator-stimulated phosphoprotein compared with tricuspid aortic valve specimens. Conclusions BAV is associated with regional disruptions in the eNOS pathway, most markedly in the right aortic region. The discrepancy between increased eNOS activity and the absence of increased NO bioavailability in this region provides insight into physiologic mechanisms potentially underlying the asymmetric dilatation pattern observed in BAV. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the association between priapism in men with sickle cell anemia (SCA) and hemorheological and hemolytical parameters. Materials and Methods: Fifty-eight men with SCA (median age: 38 years) were included; 28 who had experienced priapism at least once during their life (priapism group) and 30 who never experienced this complication (control group). Twenty-two patients were treated with hydroxycarbamide, 11 in each group. All patients were at steady state at the time of inclusion. Hematological and biochemical parameters were obtained through routine procedures. The Laser-assisted Optical Rotational Cell Analyzer was used to measure red blood cell (RBC) deformability at 30 Pa (ektacytometry) and RBC aggregation properties (laser backscatter versus time). Blood viscosity was measured at a shear rate of 225 s-1 using a cone/plate viscometer. A principal component analysis was performed on 4 hemolytic markers (i.e., lactate dehydrogenase (LDH), aspartate aminotransferase (ASAT), total bilirubin (BIL) levels and reticulocyte (RET) percentage) to calculate a hemolytic index. Results: Compared to the control group, patients with priapism exhibited higher ASAT (p = 0.01), LDH (p = 0.03), RET (p = 0.03) levels and hemolytic indices (p = 0.02). Higher RBC aggregates strength (p = 0.01) and lower RBC deformability (p = 0.005) were observed in patients with priapism compared to controls. After removing the hydroxycarbamide-treated patients, RBC deformability (p = 0.01) and RBC aggregate strength (p = 0.03) were still different between the two groups, and patients with priapism exhibited significantly higher hemolytic indices (p = 0.01) than controls. Conclusion: Our results confirm that priapism in SCA is associated with higher hemolytic rates and show for the first time that this complication is also associated with higher RBC aggregate strength and lower RBC deformability. [ABSTRACT FROM AUTHOR]

The aim of the present study was to test the effects of Pfaffia paniculata (PP) extract on the red blood cell (RBC) rheological properties of patients with sickle cell disease (SCD) and healthy (AA) individuals. Blood from 7 SCD and 4 AA individuals were collected in EDTA tubes. Washed RBCs were incubated with various concentration of PP extract: 0.0, 0.2 or 0.5 mg/ml of PP solution for 5 hrs at 37°C. RBC deformability was measured by ektacytometry at 9 shear stresses ranging from 0.3 to 30 Pa, and RBC aggregation properties were determined by laser-backscattered techniques. Because RBCs from SCD patients are fragile, a stability test was also performed to test for the fragility of RBC exposed to a constant shear stress (70 Pa) for 10 min. While RBC deformability was not improved by the use of PP extract in AA, we noted an improvement of this parameter in patients with SCD between the 0.0 and 0.5 mg/ml conditions. In contrast to AA RBCs, the fragility of SCD RBCs was not affected by PP extract. In conclusion, this study demonstrates the beneficial effects, in-vitro, of PP extract on the RBC deformability of SCD patients, notably at high shear stress (a shear stress condition usually found in capillaries). [ABSTRACT FROM AUTHOR]

Patients with hemoglobin C disease (CC) usually do not develop severe complications in comparison with individuals with sickle cell anemia (SS) or with sickle cell hemoglobin C disease (SC). The present study compared the hematological, biochemical, hemorheological and clinical characteristics of CC patients to those of SS, SC and healthy individuals (AA). Blood viscosity was measured at 225 s-1 with a cone plate viscometer. The hematocrit-to-blood viscosity ratio (HVR), i.e. an index of red blood cell (RBC) oxygen transport effectiveness, was calculated. RBC deformability was determined at 30 Pa by ektacytometry, and RBC aggregation properties by syllectometry. CC and SC had higher blood viscosity and lower HVR than AA. Nevertheless, HVR was higher in CC compared to SS and tended to be higher than in SC. The CC group exhibited very rigid hyperchromic RBC compared to the three other groups. RBC aggregation abnormalities were observed in CC: low RBC aggregation index and high RBC aggregates strength. Despite these hemorheological abnormalities, CC never had hospitalized painful vaso-occlusive crisis or acute chest syndrome. In contrast, all of them had splenomegaly.Of note, 2 out of 7 CC developed retinopathy or otologic disorders. Whether the blood hyperviscosity and decreased RBC deformability are responsible for these complications is unknown. The higher oxygen transport effectiveness (i.e., HVR) of CC compared to SS is probably at the origin of the very low risk of medical complication in this population. [ABSTRACT FROM AUTHOR]

Pannexin channels are newly discovered ATP release channels expressed throughout the body. Pannexin 1 (Panx1) channels have become of great interest as they appear to participate in a multitude of signalling cascades, including regulation of vascular function. Although numerous Panx1 pharmacological inhibitors have been discovered, these inhibitors are not specific for Panx1 and have additional effects on other proteins. Therefore, molecular tools, such as RNA interference and knockout animals, are needed to demonstrate the role of pannexins in various cellular functions. This review focuses on the known roles of Panx1 related to purinergic signalling in the vasculature focusing on post-translational modifications and channel gating mechanisms that may participate in the regulated release of ATP. [ABSTRACT FROM AUTHOR]