Severe Vascular Phenotype Research Articles

Pseudotumoral calcinosis in systemic sclerosis: Data from systematic literature review and case series from two referral centres

ObjectivesWe aimed to clarify the definition, distribution, clinical association and outcomes of large calcinosis in patients with systemic sclerosis (SSc). MethodsWe conducted a systematic literature review (SLR) focusing on SSc-related large calcified masses. Upon updating the terminology and definition, all cases of “pseudotumoral” calcinosis seen at the Cochin and Padova University Hospitals were reviewed. ResultsThe SLR yielded 30 SSc cases, with large calcified masses mainly defined as “tumoral” or “pseudotumoral”. Among the 629 SSc cases included in the Cochin and Padova cohorts, 19 (3%) living and 7 deceased patients were affected by pseudotumoral calcinosis; among these, the great majority had a severe vascular phenotype. The mean age in the whole population (56 cases) was 59 ± 11.4 years with a median disease duration at calcinosis onset of 7 (5–10) years. Twenty-five out of 56 patients (44.6%) had the diffuse cutaneous form of SSc. Anti-topisomerase I and anticentromere were found equally. Pseudotumoral calcinosis were commonly symmetrical and the size ranged from 2 to 15.5 cm. Most patients had multiple site involvement: 52% hand/wrist, 29% shoulders and elbows, 20% hips and 25% spinal calcinosis. Fistulization/ulceration and infections were reported in 32% and 23% of cases, respectively; nerve compression was found in 40% of spinal calcinosis and in one patient with limb calcinosis. There was no clear evidence of clinical and radiological improvement with any treatment. A partial improvement was seen in 7 patients that underwent surgery. ConclusionPseudotumoral calcinosis may occur in about 3% of SSc patients, commonly symmetrical and in multiple sites without differences regarding the cutaneous subtypes but often in those with a severe vascular phenotype. Medical treatment seems ineffective, whereas a surgical approach may be considered.

Regulation of Vegf signaling by natural and synthetic ligands

AbstractThe mechanisms that allow cells to bypass anti–vascular endothelial growth factor A (VEGFA) therapy remain poorly understood. Here we use zebrafish to investigate this question and first show that vegfaa mutants display a severe vascular phenotype that can surprisingly be rescued to viability by vegfaa messenger RNA injections at the 1-cell stage. Using vegfaa mutants as an in vivo test tube, we found that zebrafish Vegfbb, Vegfd, and Pgfb can also rescue these animals to viability. Taking advantage of a new vegfr1 tyrosine kinase–deficient mutant, we determined that Pgfb rescues vegfaa mutants via Vegfr1. Altogether, these data reveal potential resistance routes against current anti-VEGFA therapies. In order to circumvent this resistance, we engineered and validated new dominant negative Vegfa molecules that by trapping Vegf family members can block vascular development. Thus, our results show that Vegfbb, Vegfd, and Pgfb can sustain vascular development in the absence of VegfA, and our newly engineered Vegf molecules expand the toolbox for basic research and antiangiogenic therapy.

Skin Telangiectasia and the Identification of a Subset of Systemic Sclerosis Patients With Severe Vascular Disease.

Cutaneous telangiectasia (CT) are common in systemic sclerosis (SSc) patients, but their ability to stratify patients by risk is poorly known. We aimed to determine whether the number and size of CT were associated with the pattern of microvascular lesions assessed by nailfold videocapillaroscopy (NVC) and markers reflecting the severity of SSc-related vasculopathy. We performed a cross-sectional study, including consecutive SSc patients over a 6-month period. We also considered 3 predefined subsets of patients according to the number of hand or face CT: absence, ≤10, or >10 hand or face CT (profuse CT). Pseudotumoral CT were defined as CT with >5 mm diameter. A total of 87 patients were included, of whom 75 (86%) had CT (27 with profuse and 19 with pseudotumoral CT). Profuse and pseudotumoral CT were both associated with capillary loss (P < 0.001 and P = 0.002, respectively) and severe neoangiogenesis (P = 0.015 and P = 0.041, respectively), 2 hallmarks of the late NVC pattern. In multivariate analysis, profuse CT were independently associated with past or current digital ulcers (odds ratio [OR] 2.95 [95% confidence interval (95% CI) 1.09-19.63]), and pseudotumoral CT were independently associated with the late NVC pattern (OR 4.84 [95% CI 1.32-26.19]) and with precapillary pulmonary hypertension (OR 12.60 [95% CI 1.68-94.53]). We demonstrate that the number and size of CT are associated with the most severe NVC pattern. In addition, profuse and pseudotumoral CT identify a subset of patients with a more severe vascular phenotype. Further prospective studies should determine whether CT number and size could serve as an early clinical biomarker for the development of severe vascular disease.

Formula omitted] mutations increase thoracic aorta vulnerability to intramural damage despite a general biomechanical adaptivity

Genetic studies in patients reveal that mutations to genes that encode contractile proteins in medial smooth muscle cells can cause thoracic aortic aneurysms and dissections. Mouse models of such mutations, including Acta2−/− and Myh11R247C/R247C, surprisingly do not present with any severe vascular phenotype under normal conditions. This observation raises the question whether these mutations nevertheless render the thoracic aorta increasingly vulnerable to aneurysms or dissections in the presence of additional, epigenetic, factors such as hypertension, a known risk factor for thoracic aortic disease. Accordingly, we compared the structure and biaxial mechanical properties of the ascending and descending thoracic aorta from male wild-type and Myh11R247C/R247C mice under normotension and induced hypertension. On average, the mutant aortas exhibited near normal biomechanics under normotensive hemodynamics and near normal adaptations to hypertensive hemodynamics, yet the latter led to intramural delaminations or premature deaths in over 20% of these mice. Moreover, the delaminated vessels exhibited localized pools of mucoid material, similar to the common histopathologic characteristic observed in aortas from humans affected by thoracic aortic aneurysms and dissections. The present findings suggest, therefore, that mutations to smooth muscle cell contractile proteins may place the thoracic aorta at increased risk to epigenetic factors and that there is a need to focus on focal, not global, changes in aortic structure and properties, including the pooling of glycosaminoglycans/proteoglycans that may lead to thoracic aortic dissection.

ENOS [Glu298Asp] polymorphism, erectile function and ocular pressure in type 2 diabetes

Imbalance in nitric oxide (NO), an atheroprotective vasodilator, is associated with endothelial dysfunction, cardiovascular diseases (CVD) and diabetic complications. Various endothelial NO synthase (eNOS) polymorphisms may affect NO bioavailability, thereby promoting adverse cardiovascular milieu. To analyze glucose homeostasis, cardiometabolic phenotype, and micro- and macroangiopathies associated with eNOS G894T gene polymorphism in type 2 diabetes (T2DM). 210 T2DM outpatients (mean age (1SD) 70 (12); diabetes duration 19 (9) years; males:females 64:36%; metabolic syndrome 87%) had insulin sensitivity and b-cell function modelled with HOMA, alongside routine laboratory and endothelin measurements. GG, GT and TT genotypes represented 48% (n = 100), 39% (n = 83) and 13% (n = 27). Overall microangiopathy (retinopathy, neuropathy and/or nephropathy) was present in 74%, and overall macroangiopathy (CAD, PAD and/or TIA/stroke) in 45%. The TT genotype did not translate into a more severe vascular phenotype, as TT patients carrying the proposed risk genotype did not suffer a higher rate of micro- and macrovascular complications. On the other hand, erectile dysfunction, present in 60% of males (n = 135), was much more prevalent in TT males: 57% [GG & GT] vs. 93% in TT (p 0.0088). Ocular hypertension/glaucoma frequency (18% of the whole group) was also markedly different, albeit in opposing directions, between eNOS G894T gene polymorphism subgroups: 21% [GG & GT] vs. 0% prevalence (TT; p 0.0057). eNOS G894T gene polymorphism in homozygous TT carriers translates into opposing effects on erectile function (detrimental) and ocular hypertension/glaucoma (protective) in T2DM, without affecting glucose homeostasis determinants or the presence of micro- and macrovascular complications.

P1.03 Disruption of dystroglycan–pikachurin interaction underlies the molecular pathogenesis of eye abnormalities in dystroglycanopathy

ases fukutin and fukutin-related protein (FKRP), cause forms of muscular dystrophy (MD) associated with defective glycosylation of a-dystroglycan. The ‘‘vascular hypothesis” of MD predicts that the muscle necrosis associated with MD is caused by chronic muscle ischaemia. Since dystroglycan is known to be essential in vascular development, transgenic zebrafish expressing EGFP in the blood vessel endothelium, driven by the fli-1 promoter were treated with translational blocking morpholinos. The morpholinos were directed against the FKRP and Fukutin transcripts. At 1 day post fertilisation (dpf) the eye vasculature in both knock downs was distorted and correlated with severity of phenotype. In the embryos with the most severe phenotypes at 3 dpf the eye areas were significantly smaller than controls. In the more mildly affected morphant embryos there is a failure of the somitic intersegmental vessels to reach the dorsal longitudinal anastomosis. As the phenotype became more severe the intersegmental vessels retracted further and in some cases were found to be missing. Fukutin knock downs had a more severe vascular phenotype than FKRP knockdowns. Downregulation of FKRP and Fukutin in TG(fli1:EGFP) zebrafish may therefore provide a good model system to investigate how these deficiencies relate to vascular development.

P1.04 Some of disease-causing missense fukutin mutants mislocalize to endoplasmic reticulum

ases fukutin and fukutin-related protein (FKRP), cause forms of muscular dystrophy (MD) associated with defective glycosylation of a-dystroglycan. The ‘‘vascular hypothesis” of MD predicts that the muscle necrosis associated with MD is caused by chronic muscle ischaemia. Since dystroglycan is known to be essential in vascular development, transgenic zebrafish expressing EGFP in the blood vessel endothelium, driven by the fli-1 promoter were treated with translational blocking morpholinos. The morpholinos were directed against the FKRP and Fukutin transcripts. At 1 day post fertilisation (dpf) the eye vasculature in both knock downs was distorted and correlated with severity of phenotype. In the embryos with the most severe phenotypes at 3 dpf the eye areas were significantly smaller than controls. In the more mildly affected morphant embryos there is a failure of the somitic intersegmental vessels to reach the dorsal longitudinal anastomosis. As the phenotype became more severe the intersegmental vessels retracted further and in some cases were found to be missing. Fukutin knock downs had a more severe vascular phenotype than FKRP knockdowns. Downregulation of FKRP and Fukutin in TG(fli1:EGFP) zebrafish may therefore provide a good model system to investigate how these deficiencies relate to vascular development.

Fibrillins 1 and 2 Perform Partially Overlapping Functions during Aortic Development

Fibrillin-rich microfibrils are extracellular assemblies that impart structural properties to the connective tissue. To elucidate the contribution of fibrillin-rich microfibrils to organogenesis, we have examined the vascular phenotype of a newly created strain of mice that completely lacks fibrillin-1 and the consequences of combined deficiency of fibrillins 1 and 2 on tissue formation. The results demonstrated that fibrillins 1 and 2 perform partially overlapping functions during aortic development. Fbn1-/- mice died soon after birth from ruptured aortic aneurysm, impaired pulmonary function, and/or diaphragmatic collapse. Analysis of the neonatal Fbn1-/- aorta documented a disorganized and poorly developed medial layer but normal levels of elastin cross-links. Transcriptional profiling revealed that aneurysm progression in Fbn1 null mice is accompanied by unproductive up-regulation of gene products normally involved in tissue repair and vascular integrity, such as plasminogen activator inhibitor-1, activin A, and cysteine-rich angiogenic protein 61. In contrast to Fbn1-/- mice, Fbn2 null mice had a well developed and morphologically normal aortic wall. However, virtually all Fbn1-/-;Fbn2-/- embryos and about half of the Fbn1+/-;Fbn2-/- embryos died in utero and displayed a significantly more severe vascular phenotype than Fbn1-/- mice. Consistent with a specialized function of fibrillin-2, electron microscopy visualized ultrastructurally different microfibrils in Fbn1 null compared with control cell cultures. Collectively, these data demonstrate that involvement of fibrillin-2 in the initial assembly of the aortic matrix overlaps in part with fibrillin-1 and that continued fibrillin-1 deposition is absolutely required for the maturation and function of the vessel during neonatal life.

The Sphingosine-1-phosphate Receptors S1P1, S1P2, and S1P3 Function Coordinately during Embryonic Angiogenesis

Sphingosine-1-phosphate (S1P) elicits diverse cellular responses through a family of G-protein-coupled receptors. We have shown previously that genetic disruption of the S1P(1) receptor, the most widely expressed of the family, results in embryonic lethality because of its key role within endothelial cells in regulating the coverage of blood vessels by vascular smooth muscle cells. To understand the physiologic functions of the two other widely expressed S1P receptors, we generated S1P(2) and S1P(3) null mice. Neither the S1P(2) null mice nor the S1P(3) null mice exhibited significant embryonic lethality or obvious phenotypic abnormalities. To unmask possible overlapping or collaborative functions between the S1P(1), S1P(2), and S1P(3) receptors, we examined embryos with multiple S1P receptor mutations. We found that S1P(1) S1P(2) double null and S1P(1) S1P(2) S1P(3) triple null embryos displayed a substantially more severe vascular phenotype than did embryos with only S1P(1) deleted. We also found partial embryonic lethality and vascular abnormalities in S1P(2) S1P(3) double null embryos. Our results indicate that the S1P(1), S1P(2) and S1P(3) receptors have redundant or cooperative functions for the development of a stable and mature vascular system during embryonic development.