Publications by authors named "Brigida Santos"

Article Synopsis
  • Parasitic infections significantly affect children in developing countries, particularly those with sickle cell disease (SCD), leading to increased anemia and transfusion needs.
  • A study in Angola found that over half of the children sampled had at least one parasitic infection, with many experiencing co-infections, especially in rural areas.
  • The presence of intestinal parasites was linked to changes in gut microbiome composition, reducing beneficial bacteria while correlating with higher leukocyte counts and lower hemoglobin levels in SCD patients with ascariasis.
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Background: Realizing Effectiveness Across Continents with Hydroxyurea (REACH) is an open-label non-randomised trial of hydroxyurea (hydroxycarbamide) in children with sickle cell anaemia in sub-Saharan Africa. The short-term results of REACH on safety, feasibility, and effectiveness of hydroxyurea were published previously. In this paper we report results from extended hydroxyurea treatment in the REACH cohort up to 8 years.

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Article Synopsis
  • * Researchers analyzed samples from 192 patients, discovering over 5 million high-quality genetic variants and identifying specific genes associated with worsening vaso-occlusive crises (VOC) and lower fetal hemoglobin (HbF) levels.
  • * This research highlights the complex genetic factors influencing SCA symptoms and represents the first detailed investigation of its clinical variations in Angola, suggesting potential genetic modifiers related to patient phenotypes.
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Children with sickle cell anemia (SCA) in Africa frequently require transfusions for SCA complications. Despite limited blood supplies, strategies to reduce their transfusion needs have not been widely evaluated or implemented. We analyzed transfusion utilization in children with SCA before and during hydroxyurea treatment.

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Article Synopsis
  • - The study focused on Angolan children aged 3 to 12 with Sickle Cell Anemia (SCA), assessing their response to a 12-month hydroxyurea (HU) treatment and its potential side effects.
  • - Out of 215 enrolled patients, 141 completed the treatment, showing a significant decrease in clinical events like blood transfusions (53.4% reduction) and hospitalizations (47.1% reduction), with a mean increase in fetal hemoglobin (HbF) of 11.9%.
  • - The results indicated that while there was variability in treatment response among patients, HU was generally well-tolerated with no major clinical side effects, highlighting its potential to improve survival among children with S
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Sickle cell anemia (SCA) causes a long-standing vascular inflammation state, leading to endothelial dysfunction and chronic overexpression of several adhesion molecules, which contributes to acute and constant vaso-occlusive (VOC) episodes. It has been demonstrated that hydroxyurea (HU) can reduce VOC events, organ damage, blood transfusions, and even the adhesion properties to endothelial cells of SCA subjects. Due to VOC episodes, these patients are also more susceptible to recurrent bacterial translocation and dysbiosis.

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Sickle cell disease (SCD) is a life-threatening blood disorder affecting >500 000 infants annually, mostly in sub-Saharan Africa. Most infants do not have access to an early diagnosis and die early from treatable complications of SCD. Universal newborn screening (NBS) is not yet available in any African country for a variety of reasons, including lack of laboratory capacity, difficulty in tracking affected infants, and the relatively short stay of mothers and newborns at maternity hospitals.

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Sickle cell anemia (SCA) is an inherited disease affecting the hemoglobin that is particularly common in sub-Saharan Africa. Although monogenic, phenotypes are markedly heterogeneous in terms of severity and life span. Hydroxyurea is still the most common treatment for these patients, and the response to treatment is highly variable and seems to be an inherited trait.

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This study aimed to synthesize the evidence on the effects of disease-modifying agents for managing sickle cell disease (SCD) in children and adolescents by means of a systematic review with network meta-analyses, surface under the cumulative ranking curve (SUCRA) and stochastic multicriteria acceptability analyses (SMAA) (CRD42022328471). Eightteen randomized controlled trials (hydroxyurea [n = 7], l-arginine [n = 3], antiplatelets [n = 2], immunotherapy/monoclonal antibodies [n = 2], sulfates [n = 2], docosahexaenoic acid [n = 1], niprisan [n = 1]) were analyzed. SUCRA and SMAA demonstrated that hydroxyurea at higher doses (30 mg/kg/day) or at fixed doses (20 mg/kg/day) and immunotherapy/monoclonal antibodies are more effective for preventing vaso-occlusive crisis (i.

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Article Synopsis
  • * Over the course of the study, 717 malaria episodes occurred among participants, with associations found between malaria risk and factors like absolute neutrophil count (ANC) and splenomegaly, while other variables did not significantly impact risk.
  • * The findings suggest that hydroxyurea treatment may lower malaria incidence due to mechanisms not yet fully understood; notable is that lower ANC levels were beneficial, while mild splenomegaly heightened malaria
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Sickle cell disease (SCD) is one of the most common genetic conditions worldwide. It can contribute up to 90% of under-5 mortality in sub-Saharan Africa. Clinical manifestations are very heterogeneous, and the intestinal microbiome appears to be crucial in the modulation of inflammation, cell adhesion and induction of aged neutrophils, the main interveners of recurrent vaso-occlusive crisis.

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Article Synopsis
  • Sickle Cell Anemia (SCA) is a genetic disease linked to a mutation in the HBB gene, leading to sickle-shaped red blood cells and various health complications, particularly in pediatric patients in Angola.
  • The study involved 200 SCA children and analyzed their clinical data, as well as specific gene polymorphisms, revealing that certain variants in the CD36, VCAM1, and NOS3 genes significantly affect the severity of anemia and related health outcomes.
  • This research is the first to demonstrate the role of these genetic modifiers in the expression of SCA symptoms among Angolan children, suggesting that they could help predict disease severity and treatment needs.
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Sickle cell anemia (SCA) is an inherited hematological disorder and a serious global health problem, especially in Sub-Saharan Africa. Although hydroxyurea (HU) is the leading treatment for patients with SCA, its effects on the gut microbiome have not yet been explored. In this context, the aim of this study was to investigate this association by characterizing the gut microbiome of an Angolan SCA pediatric population before and after 6 months of HU treatment.

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Background: Sickle cell anemia (SCA) is an inherited blood disorder that affects over 300,000 newborns worldwide every year, being particularly prevalent in Sub-Saharan Africa. Despite being a monogenic disease, SCA shows a remarkably high clinical heterogeneity. Several studies have already demonstrated the existence of some polymorphisms that can provide major clinical benefits, producing a mild phenotype.

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The aim of this study was to explore the association between alpha-thalassemia, fetal hemoglobin, hematological indices, and clinical adverse events in Angolan sickle cell disease pediatric patients. A total of 200 sickle cell disease (SCD) children were sampled in Luanda and Caxito. A venous blood sample was collected and used for hematological analyses, fetal hemoglobin quantification, and genotyping of 3.

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In an effort to explore new knowledge and to develop meaningful collaborations for improving child health, the First Pan African Workshop on Newborn Screening was convened in June 2019 in Rabat, Morocco. Participants included an informal network of newborn screening stakeholders from across Africa and global experts in newborn screening and sickle cell disease. Over 150 attendees, representing 20 countries, were present including 11 African countries.

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Background: Hydroxyurea is an effective treatment for sickle cell anemia, but few studies have been conducted in sub-Saharan Africa, where the burden is greatest. Coexisting conditions such as malnutrition and malaria may affect the feasibility, safety, and benefits of hydroxyurea in low-resource settings.

Methods: We enrolled children 1 to 10 years of age with sickle cell anemia in four sub-Saharan countries.

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Despite its well-described safety and efficacy in the treatment of sickle cell anemia (SCA) in high-income settings, hydroxyurea remains largely unavailable in sub-Saharan Africa, where more than 75% of annual SCA births occur and many comorbidities exist. Realizing Effectiveness Across Continents with Hydroxyurea (REACH, ClinicalTrials.gov NCT01966731) is a prospective, Phase I/II open-label trial of hydroxyurea designed to evaluate the feasibility, safety, and benefits of hydroxyurea treatment for children with SCA in four sub-Saharan African countries.

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Objective: To assess the cost-effectiveness of a pilot newborn screening (NBS) and treatment program for sickle cell anemia (SCA) in Luanda, Angola.

Study Design: In July 2011, a pilot NBS and treatment program was implemented in Luanda, Angola. Infants identified with SCA were enrolled in a specialized SCA clinic in which they received preventive care and sickle cell education.

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Severe anemia is an important cause of morbidity and mortality among children in resource-poor settings, but laboratory diagnostics are often limited in these locations. To address this need, we developed a simple, inexpensive, and color-based point-of-care (POC) assay to detect severe anemia. The purpose of this study was to evaluate the accuracy of this novel POC assay to detect moderate and severe anemia in a limited-resource setting.

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Background: Sickle cell anemia (SCA) is an inherited hematological disorder that causes a large but neglected global health burden, particularly in Africa. Hydroxyurea represents the only available disease-modifying therapy for SCA, and has proven safety and efficacy in high-resource countries. In sub-Saharan Africa, there is minimal use of hydroxyurea, due to lack of data, absence of evidence-based guidelines, and inexperience among healthcare providers.

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Over 300,000 infants are born annually with sickle cell anemia (SCA) in sub-Saharan Africa, and >50% die young from infection or anemia, usually without diagnosis of SCA. Early identification by newborn screening (NBS), followed by simple interventions dramatically reduced the mortality of SCA in the United States, but this strategy is not yet established in Africa. We designed and implemented a proof-of-principle NBS and treatment program for SCA in Angola, with focus on capacity building and local ownership.

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