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Peripheral artery disease (PAD) is the narrowing of the arteries that carry blood to the lower extremities. PAD has been traditionally associated with atherosclerosis. However, recent studies have found that medial arterial calcification (MAC) is the primary cause of chronic limb ischemia below the knee. MAC involves calcification of the elastin fibers surrounding smooth muscle cells (SMCs) in arteries. Matrix GLA Protein (MGP) binds circulating calcium and inhibits vascular calcification. Mgp -/- mice develop severe MAC and die within 8 weeks of birth due to aortic rupture or heart failure. We previously discovered a rare genetic disease Arterial Calcification due to Deficiency in CD73 (ACDC) in which patients present with extensive MAC in their lower extremity arteries. Using a patient-specific induced pluripotent stem cell model we found that rapamycin inhibited calcification. Here we investigated whether rapamycin could reduce MAC in vivo using Mgp -/- mice as a model. Mgp +/+ and Mgp -/- mice received 5mg/kg rapamycin or vehicle. Calcification content was assessed via microCT, and vascular morphology and extracellular matrix content assessed histologically. Immunostaining and western blot analysis were used to examine SMC phenotypes and cellular functions. Rapamycin prolonged Mgp -/- mice lifespan, decreased mineral density in the arteries, and increased smooth muscle actin protein levels, however, calcification volume, vessel morphology, SMC proliferation, and autophagy flux were all unchanged. These findings suggest that rapamycin's effects in the Mgp -/- mouse are independent of the vascular phenotype.
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Case series summary: Cystic bronchiectasis was diagnosed in three cats with known histories of chronic coughing using CT and histopathology. CT of the lungs revealed large space-occupying lesions that compressed and displaced unaffected pulmonary parenchyma and vessels. The masses were soft tissue attenuating in two cases and gas-cavitated with areas of dependent fluid in one case. All three cats were found to have mineral attenuating material in lesions and in other dilatated airways. Generalized bronchial wall thickening was also present and indicative of chronic lower airway disease. These findings were supported by histopathology showing inflammatory changes and dilatated airways in the collected tissues. In the two cases in which post-contrast CT series were acquired, the lesions had rim-enhancement. Relevance and novel information: Cystic bronchiectasis is a rare presentation of bronchiectasis in cats and may mimic a pulmonary mass lesion, which could be mistaken for neoplasia or abscessation. The lack of central enhancement or presence of gas cavitation on CT, concurrent presence of diffuse bronchial wall thickening, other areas of bronchiectasis and the presence of broncholithiasis may alert the clinician to the possibility of cystic bronchiectasis related to chronic lower airway disease.
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Arterial calcification due to deficiency of CD73 (ACDC) is a rare genetic disease caused by a loss-of-function mutation in the NT5E gene encoding the ecto-5'-nucleotidase (cluster of differentiation 73, CD73) enzyme. Patients with ACDC develop vessel arteriomegaly, tortuosity, and vascular calcification in their lower extremity arteries. Histological analysis shows that patients with ACDC vessels exhibit fragmented elastin fibers similar to that seen in aneurysmal-like pathologies. It is known that alterations in transforming growth factor ß (TGFß) pathway signaling contribute to this elastin phenotype in several connective tissue diseases, as TGFß regulates extracellular matrix (ECM) remodeling. Our study investigates whether CD73-derived adenosine modifies TGFß signaling in vascular smooth muscle cells (SMCs). We show that Nt5e-/- SMCs have elevated contractile markers and elastin gene expression compared with Nt5e+/+ SMCs. Ecto-5'-nucleotidase (Nt5e)-deficient SMCs exhibit increased TGFß-2 and activation of small mothers against decapentaplegic (SMAD) signaling, elevated elastin transcript and protein, and potentiate SMC contraction. These effects were diminished when the A2b adenosine receptor was activated. Our results identify a novel link between adenosine and TGFß signaling, where adenosine signaling via the A2b adenosine receptor attenuates TGFß signaling to regulate SMC homeostasis. We discuss how disruption in adenosine signaling is implicated in ACDC vessel tortuosity and could potentially contribute to other aneurysmal pathogenesis.
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5'-Nucleotidase , Adenosina , Adenosina/metabolismo , Elastina/genética , Transdução de Sinais , Fator de Crescimento Transformador betaRESUMO
Calcific aortic valve disease (CAVD) is present in nearly a third of the elderly population. Thickening, stiffening, and calcification of the aortic valve causes aortic stenosis and contributes to heart failure and stroke. Disease pathogenesis is multifactorial, and stresses such as inflammation, extracellular matrix remodeling, turbulent flow, and mechanical stress and strain contribute to the osteogenic differentiation of valve endothelial and valve interstitial cells. However, the precise initiating factors that drive the osteogenic transition of a healthy cell into a calcifying cell are not fully defined. Further, the only current therapy for CAVD-induced aortic stenosis is aortic valve replacement, whereby the native valve is removed (surgical aortic valve replacement, SAVR) or a fully collapsible replacement valve is inserted via a catheter (transcatheter aortic valve replacement, TAVR). These surgical procedures come at a high cost and with serious risks; thus, identifying novel therapeutic targets for drug discovery is imperative. To that end, the present study develops a workflow where surgically removed tissues from patients and donor cadaver tissues are used to create patient-specific primary lines of valvular cells for in vitro disease modeling. This protocol introduces the utilization of a cold storage solution, commonly utilized in organ transplant, to reduce the damage caused by the often-lengthy procurement time between tissue excision and laboratory processing with the benefit of greatly stabilizing cells of the excised tissue. The results of the present study demonstrate that isolated valve cells retain their proliferative capacity and endothelial and interstitial phenotypes in culture upwards of several days after valve removal from the donor. Using these materials allows for the collection of control and CAVD cells, from which both control and disease cell lines are established.
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Estenose da Valva Aórtica/fisiopatologia , Valva Aórtica/patologia , Calcinose/fisiopatologia , Valva Aórtica/fisiopatologia , Feminino , Humanos , Técnicas In Vitro , MasculinoRESUMO
OBJECTIVE: The recessive disease arterial calcification due to deficiency of CD73 (ACDC) presents with extensive nonatherosclerotic medial layer calcification in lower extremity arteries. Lack of CD73 induces a concomitant increase in TNAP (tissue nonspecific alkaline phosphatase; ALPL), a key enzyme in ectopic mineralization. Our aim was to investigate how loss of CD73 activity leads to increased ALPL expression and calcification in CD73-deficient patients and assess whether this mechanism may apply to peripheral artery disease calcification. Approach and Results: We previously developed a patient-specific disease model using ACDC primary dermal fibroblasts that recapitulates the calcification phenotype in vitro. We found that lack of CD73-mediated adenosine signaling reduced cAMP production and resulted in increased activation of AKT. The AKT/mTOR (mammalian target of rapamycin) axis blocks autophagy and inducing autophagy prevented calcification; however, we did not observe autophagy defects in ACDC cells. In silico analysis identified a putative FOXO1 (forkhead box O1 protein) binding site in the human ALPL promoter. Exogenous AMP induced FOXO1 nuclear localization in ACDC but not in control cells, and this was prevented with a cAMP analogue or activation of A2a/2b adenosine receptors. Inhibiting FOXO1 reduced ALPL expression and TNAP activity and prevented calcification. Mutating the FOXO1 binding site reduced ALPL promoter activation. Importantly, we provide evidence that non-ACDC calcified femoropopliteal arteries exhibit decreased CD73 and increased FOXO1 levels compared with control arteries. CONCLUSIONS: These data show that lack of CD73-mediated cAMP signaling promotes expression of the human ALPL gene via a FOXO1-dependent mechanism. Decreased CD73 and increased FOXO1 was also observed in more common peripheral artery disease calcification.
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5'-Nucleotidase/deficiência , Fibroblastos/enzimologia , Proteína Forkhead Box O1/metabolismo , Doença Arterial Periférica/enzimologia , Artéria Poplítea/enzimologia , Calcificação Vascular/enzimologia , 5'-Nucleotidase/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Autofagia , Estudos de Casos e Controles , Células Cultivadas , Feminino , Fibroblastos/patologia , Proteína Forkhead Box O1/genética , Proteínas Ligadas por GPI/deficiência , Proteínas Ligadas por GPI/genética , Humanos , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/genética , Doença Arterial Periférica/patologia , Artéria Poplítea/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Calcificação Vascular/genética , Calcificação Vascular/patologia , Adulto JovemRESUMO
BACKGROUND: Structural differences between the brains of people with schizophrenia and control subjects are highly replicated but the timing and clinical correlates are unclear. In the Edinburgh High Risk Study, we have followed up 162 individuals at high genetic risk of schizophrenia and 36 healthy control subjects over 10 years. METHODS: Participants received detailed clinical and up to five structural magnetic resonance imaging (MRI) assessments at 2-year intervals. All 436 MRI scans acquired were parcellated and adjusted for between-scanner differences. The trajectory of any structural MRI changes was then investigated using mixed effects analysis of variance. RESULTS: Seventeen of the 146 high-risk subjects who were scanned developed schizophrenia over the 8 years of the study. People at high genetic risk of schizophrenia had significantly greater reductions over time than the control group for whole brain volume and left and right prefrontal and temporal lobes. Greater prefrontal reductions were shown in high-risk subjects who subsequently became unwell compared with those who did not. These changes were significantly associated with increasing severity of psychotic symptoms. CONCLUSIONS: Individuals at high genetic risk of schizophrenia exhibited reductions in cerebral volume that were not found in control subjects. Changes in brain structure were also associated with increasing psychotic symptom severity as people developed schizophrenia. The progressive reductions found in those who went on to develop schizophrenia suggest an additional brain insult near to the time of onset.
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Encéfalo/patologia , Transtornos Psicóticos/etiologia , Esquizofrenia/complicações , Esquizofrenia/patologia , Adolescente , Adulto , Feminino , Lateralidade Funcional , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética/métodos , Masculino , Escalas de Graduação Psiquiátrica , Fatores de Risco , Esquizofrenia/genética , Adulto JovemRESUMO
Bipolar disorder and schizophrenia are highly heritable conditions that are associated with structural brain abnormalities. Although brain abnormalities are found in the well relatives of people with schizophrenia, the extent to which genetic liability relates to brain structure in either disorder is still unclear. This study sought to ascertain the effects of genetic liability to schizophrenia and bipolar disorder on white and grey matter volume in patients with these diagnoses and their well relatives. Seventy-one patients and 72 unaffected relatives were recruited for the study. Patients included those with schizophrenia from families affected by schizophrenia alone, those with bipolar disorder from families affected by bipolar disorder alone and those with bipolar disorder from families affected by both bipolar disorder and schizophrenia. Samples of unaffected relatives of each patient group were also recruited. Subjects underwent an MRI scan of the brain, which was analysed using optimised voxel-based morphometry (VBM). Grey and white matter volume was then related to a continuous measure of genetic liability based on a threshold-liability model. Genetic liability to schizophrenia was associated with decreased grey matter volume in dorso- (DLPFC) and ventrolateral prefrontal (VLPFC) cortices. The relationship remained after diagnostic status had been taken into account. Complementary white matter changes were also demonstrated. No relationship was demonstrated between a genetic liability to bipolar disorder and either white or grey matter volume. Genes that raise the likelihood of developing schizophrenia may exert their effects by diminishing grey matter volume in the DLPFC and VLPFC and their associated white matter connections. Genes for bipolar illness might have subtle effects on brain structure, which may need particularly large samples to detect.