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Bull World Health Organ ; 98(12): 859-868, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33293746


Objective: To determine the regional- and district-level newborn prevalence of sickle cell trait and disease, and the prevalence of haemoglobin variants and genetic modifiers of sickle cell disease, in the nine regions of north-western United Republic of Tanzania. Methods: We repurposed dried blood spot samples from children (aged 0-24 months) born to mothers living with human immunodeficiency virus (HIV), collected as part of the HIV Early Infant Diagnosis programme, for sickle cell diagnosis. We performed isoelectric focusing to determine whether samples had normal haemoglobin, sickle cell trait, sickle cell disease or a rare haemoglobin variant. We shipped samples diagnosed as disease or variant to Cincinnati Children's Hospital in the United States of America for deoxyribonucleic-acid-based analyses to determine the prevalence of α-thalassaemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency or fetal haemoglobin genetic modifiers. Findings: We analysed a total of 17 200 specimens during February 2017-May 2018. We observed a prevalence of sickle cell trait and disease of 20.3% (3492/17 200) and 1.2% (210/17 200), respectively. District-level trait varied from 8.6% (5/58) to 28.1% (77/274). Among confirmed sickle cell disease specimens, we noted 42.7% (61/143) had 1-gene deletion and 14.7% (21/143) had 2-gene deletion α-thalassaemia trait. We documented G6PD A- deficiency in 19.2% (14/73) of males. Conclusion: Our calculated prevalence is twice as high as previously reported and reinforces the need for enhanced sickle cell diagnostic services. Our district-level data will inform public health policy, allowing screening and disease-modifying hydroxyurea therapy to be focused on high-prevalence areas, until universal newborn screening is available.

Pediatr Blood Cancer ; 66(8): e27807, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31094093


BACKGROUND: The Uganda Sickle Surveillance Study provided evidence for a large sickle burden among HIV-exposed infants in Uganda. To date, however, no large scale screening program has been developed for Central or East Africa. METHODS: A 3-year targeted sickle cell screening project in Uganda was designed by the Ministry of Health to (1) determine sickle cell trait and disease prevalence within high-burden districts, (2) document the prevalence among HIV-exposed and nonexposed children, (3) confirm previously suggested HIV comorbidity, and (4) estimate the co-inheritance of known genetic modifiers of sickle cell disease. RESULTS: A total of 163 334 dried blood spot samples collected between April 2015 and March 2018 were analyzed, including 112 352 samples within the HIV Early Infant Diagnosis program. A high burden with >1% sickle cell disease was found within targeted East Central and Mid-Northern districts, in both HIV-exposed and nonexposed children. Based on crude birth-rate data, 236 905 sickle cell trait births and 16 695 sickle cell disease births will occur annually in Uganda. Compared to sickle cell disease without HIV, the odds ratio of having sickle cell disease plus HIV was 0.50 (95% confidence interval = 0.40-0.64, P < .0001). Alpha-thalassemia trait and G6PD deficiency were common with sickle cell disease, but with different geospatial distribution. CONCLUSIONS: High sickle cell burden and potential HIV comorbidity are confirmed in Uganda. Genetic modifiers are common and likely influence laboratory and clinical phenotypes. These prospective data document that targeted sickle cell screening is feasible and effective in Uganda, and support development of district-level comprehensive care programs.

Anemia Falciforme/diagnóstico , Genes Modificadores , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Infecções por HIV/diagnóstico , Programas de Rastreamento/métodos , Talassemia alfa/diagnóstico , Anemia Falciforme/complicações , Anemia Falciforme/epidemiologia , Anemia Falciforme/genética , Pré-Escolar , Comorbidade , Feminino , Seguimentos , Deficiência de Glucosefosfato Desidrogenase/complicações , Deficiência de Glucosefosfato Desidrogenase/epidemiologia , Deficiência de Glucosefosfato Desidrogenase/genética , HIV/genética , HIV/isolamento & purificação , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Infecções por HIV/genética , Humanos , Lactente , Recém-Nascido , Masculino , Prevalência , Prognóstico , Estudos Prospectivos , Talassemia alfa/complicações , Talassemia alfa/epidemiologia , Talassemia alfa/genética
Blood Adv ; 2(21): 3035-3044, 2018 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-30425067


In sub-Saharan Africa, inherited causes of anemia are common, but data are limited regarding the geographical prevalence and coinheritance of these conditions and their overall contributions to childhood anemia. To address these questions in Malawi, we performed a secondary analysis of the 2015-2016 Malawi Micronutrient Survey, a nationally and regionally representative survey that estimated the prevalence of micronutrient deficiencies and evaluated both inherited and noninherited determinants of anemia. Children age 6 to 59 months were sampled from 105 clusters within the 2015-2016 Malawi Demographic Health Survey. Hemoglobin, ferritin, retinol binding protein, malaria, and inflammatory biomarkers were measured from venous blood. Molecular studies were performed using dried blood spots to determine the presence of sickle cell disease or trait, α-thalassemia trait, and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Of 1279 eligible children, 1071 were included in the final analysis. Anemia, iron deficiency, and malaria were common, affecting 30.9%, 21.5%, and 27.8% of the participating children, respectively. α-Thalassemia trait was common (>40% of children demonstrating deletion of 1 [33.1%] or 2 [10.0%] α-globin genes) and associated with higher prevalence of anemia (P < .001). Approximately 20% of males had G6PD deficiency, which was associated with a 1.0 g/dL protection in hemoglobin decline during malaria infection (P = .02). These data document that inherited blood disorders are common and likely play an important role in the prevalence of anemia and malaria in Malawian children.

Anemia/diagnóstico , Transtornos Herdados da Coagulação Sanguínea/diagnóstico , Malária/diagnóstico , Anemia/complicações , Anemia/epidemiologia , Anemia/patologia , Anemia Falciforme/complicações , Anemia Falciforme/diagnóstico , Transtornos Herdados da Coagulação Sanguínea/complicações , Transtornos Herdados da Coagulação Sanguínea/epidemiologia , Pré-Escolar , Análise Discriminante , Feminino , Genótipo , Deficiência de Glucosefosfato Desidrogenase/complicações , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Deficiência de Glucosefosfato Desidrogenase/genética , Humanos , Malária/complicações , Malária/epidemiologia , Malaui/epidemiologia , Masculino , Prevalência , Índice de Gravidade de Doença , Talassemia alfa/complicações , Talassemia alfa/diagnóstico , Talassemia alfa/genética
J Neurosci ; 37(14): 3776-3788, 2017 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-28275164


Multiple sclerosis (MS) is a neuroinflammatory, demyelinating disease of the CNS. Fibrinogen deposition at sites of blood-brain barrier breakdown is a prominent feature of neuroinflammatory disease and contributes to disease severity. Plasminogen, the primary fibrinolytic enzyme, also modifies inflammatory processes. We used a murine model of MS, experimental autoimmune encephalomyelitis (EAE), to evaluate the hypothesis that the loss of plasminogen would exacerbate neuroinflammatory disease. However, contrary to initial expectations, EAE-challenged plasminogen-deficient (Plg-) mice developed significantly delayed disease onset and reduced disease severity compared with wild-type (Plg+) mice. Similarly, pharmacologic inhibition of plasmin activation with tranexamic acid also delayed disease onset. The T-cell response to immunization was similar between genotypes, suggesting that the contribution of plasminogen was downstream of the T-cell response. Spinal cords from EAE-challenged Plg- mice demonstrated significantly decreased demyelination and microglial/macrophage accumulation compared with Plg+ mice. Although fibrinogen-deficient mice or mice with combined deficiencies of plasminogen and fibrinogen had decreased EAE severity, they did not exhibit the delay in EAE disease onset, as seen in mice with plasminogen deficiency alone. Together, these data suggest that plasminogen and plasmin-mediated fibrinolysis is a key modifier of the onset of neuroinflammatory demyelination.SIGNIFICANCE STATEMENT Multiple sclerosis is a severe, chronic, demyelinating disease. Understanding the pathobiology related to the autoreactive T-cell and microglial/macrophage demyelinating response is critical to effectively target therapeutics. We describe for the first time that deficiency of plasminogen, the key fibrinolytic enzyme, delays disease onset and protects from the development of the paralysis associated with a murine model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). Administration of a widely used, pharmacologic inhibitor of plasminogen activation, tranexamic acid, also delays the onset of neuroinflammation associated with EAE.

Doenças Desmielinizantes/metabolismo , Doenças Desmielinizantes/prevenção & controle , Encefalomielite Autoimune Experimental/metabolismo , Encefalomielite Autoimune Experimental/prevenção & controle , Paralisia/metabolismo , Paralisia/prevenção & controle , Plasminogênio/deficiência , Animais , Células Cultivadas , Doenças Desmielinizantes/patologia , Encefalomielite Autoimune Experimental/patologia , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Paralisia/patologia
Blood ; 128(5): 721-31, 2016 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-27252233


Thrombin-mediated proteolysis is central to hemostatic function but also plays a prominent role in multiple disease processes. The proteolytic conversion of fII to α-thrombin (fIIa) by the prothrombinase complex occurs through 2 parallel pathways: (1) the inactive intermediate, prethrombin; or (2) the proteolytically active intermediate, meizothrombin (fIIa(MZ)). FIIa(MZ) has distinct catalytic properties relative to fIIa, including diminished fibrinogen cleavage and increased protein C activation. Thus, fII activation may differentially influence hemostasis and disease depending on the pathway of activation. To determine the in vivo physiologic and pathologic consequences of restricting thrombin generation to fIIa(MZ), mutations were introduced into the endogenous fII gene, resulting in expression of prothrombin carrying 3 amino acid substitutions (R157A, R268A, and K281A) to limit activation events to yield only fIIa(MZ) Homozygous fII(MZ) mice are viable, express fII levels comparable with fII(WT) mice, and have reproductive success. Although in vitro studies revealed delayed generation of fIIa(MZ) enzyme activity, platelet aggregation by fII(MZ) is similar to fII(WT) Consistent with prior analyses of human fIIa(MZ), significant prolongation of clotting times was observed for fII(MZ) plasma. Adult fII(MZ) animals displayed significantly compromised hemostasis in tail bleeding assays, but did not demonstrate overt bleeding. More notably, fII(MZ) mice had 2 significant phenotypic advantages over fII(WT) animals: protection from occlusive thrombosis after arterial injury and markedly diminished metastatic potential in a setting of experimental tumor metastasis to the lung. Thus, these novel animals will provide a valuable tool to assess the role of both fIIa and fIIa(MZ) in vivo.

Precursores Enzimáticos/metabolismo , Hemostasia , Protrombina/metabolismo , Trombina/metabolismo , Alelos , Animais , Coagulação Sanguínea , Retração do Coágulo , Venenos de Crotalídeos , Embrião de Mamíferos/metabolismo , Fibrose , Metaloendopeptidases , Camundongos Endogâmicos C57BL , Miocárdio/patologia , Metástase Neoplásica , Agregação Plaquetária , Análise de Sobrevida , Trombose/metabolismo , Trombose/patologia
Cancer Res ; 75(19): 4235-43, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26238780


Thrombin-mediated proteolysis is a major determinant of metastasis, but is not universally important for primary tumor growth. Here, we report that colorectal adenocarcinoma represents one important exception whereby thrombin-mediated functions support both primary tumor growth and metastasis. In contrast with studies of multiple nongastrointestinal cancers, we found that the growth of primary tumors formed by murine and human colon cancer cells was reduced in mice by genetic or pharmacologic reduction of circulating prothrombin. Reduced prothrombin expression was associated with lower mitotic indices and invasion of surrounding tissue. Mechanistic investigations revealed that thrombin-driven colonic adenocarcinoma growth relied upon at least two targets of thrombin-mediated proteolysis, protease-activated receptor-1 (PAR-1) expressed by stromal cells and the extracellular matrix protein, fibrinogen. Colonic adenocarcinoma growth was reduced in PAR-1-deficient mice, implicating stromal cell-associated PAR-1 as one thrombin target important for tumor outgrowth. Furthermore, tumor growth was dramatically impeded in fibrinogen-deficient mice, offering the first direct evidence of a critical functional role for fibrinogen in malignant tumor growth. Tumors harvested from fibrinogen-deficient mice displayed a relative reduction in cell proliferative indices, as well as increased tumor necrosis and decreased tumor vascular density. Collectively, our findings established a functional role for thrombin and its targets PAR-1 and fibrinogen in the pathogenesis of colonic adenocarcinoma, supporting tumor growth as well as local invasion and metastasis.

Adenocarcinoma/patologia , Neoplasias do Colo/patologia , Fibrinogênio/fisiologia , Receptor PAR-1/fisiologia , Trombina/fisiologia , Adenocarcinoma/irrigação sanguínea , Adenocarcinoma/metabolismo , Afibrinogenemia/complicações , Afibrinogenemia/genética , Animais , Divisão Celular , Linhagem Celular Tumoral , Neoplasias do Colo/irrigação sanguínea , Neoplasias do Colo/metabolismo , Progressão da Doença , Feminino , Células HCT116/transplante , Xenoenxertos , Humanos , Masculino , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Nus , Invasividade Neoplásica , Neovascularização Patológica/fisiopatologia , Protrombina/análise , Receptor PAR-1/deficiência , Células Estromais/metabolismo , Trombina/deficiência , Carga Tumoral , Microambiente Tumoral