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- Comparative efficacy and safety of pharmacological interventions for managing sickle cell disease complications in children and adolescents: a systematic review with network meta-analysesPublication . Tonin, Fernanda; Ginete, Catarina; Ferreira, Joao; Delgadinho, Mariana; Fernandez-Llimos, Fernando; Brito, MiguelObjectives: Sickle cell disease (SCD), an inherited hemoglobinopathy that causes anemia, severe pain, and vaso-occlusive crisis (VOC), is currently recognized as a global public health concern, being the leading cause of pediatric stroke. Our aim was to synthesize the evidence on the efficacy and safety of interventions for managing SCD in this population. Methods: A systematic review with searches in PubMed, Scopus, and Web of Science was performed (April-2022). Randomized controlled trials comparing disease-modifying agents in SCD patients under 18 years old were included. For each outcome of interest, data were pooled by means of Bayesian network meta-analyses with the surface under the cumulative ranking curve analyses (SUCRA). Results were reported as odds ratio (OR) with 95% credibility intervals (CrI). Results: Seventeen trials (1982-2022) mostly from African countries (65%) and North America (53%), assessing the effect of different interventions’ regimens (hydroxyurea [n=6 trials], L-arginine [n=3], antiplatelets [n=2], immunotherapy/monoclonal antibodies [n=2], sulfates [n=2], docosahexaenoic acid [n=1], niprisan [n=1]) and placebo were included. No statistical differences among treatments were found for the main outcomes. SUCRA revealed that immunotherapy/monoclonal antibodies and hydroxyurea 20 mg/kg are potentially more effective against acute chest syndrome (83% and 76% probabilities, respectively), VOC (71% and 80%, respectively) and needing of transfusions (72% and 75%, respectively), while L-arginine (100-200 mg/kg) and placebo were more prone to these events. Although therapies were overall considered safe, antiplatelet and sulfates may lead to more discontinuations and severe adverse events (uncertainty evidence). Results were similar between age subgroups (<10 years vs. 10-19 years). Conclusions: The available evidence on the effect of drugs on managing SCD in children and adolescents is insufficient and weak. No clear definition for some outcomes exists. Hydroxyurea may remain the standard of care for this population, however, long-term well-designed, and well-reported trials comparing new immunotherapy/monoclonal antibodies should be performed.
- How hydroxyurea alters the gut microbiome: a longitudinal study involving Angolan children with sickle cell anemiaPublication . Delgadinho, Mariana; Ginete, Catarina; Santos, Brígida; Fernandes, Carolina; Silva, Carina; Miranda, Armandina; Vasconcelos, Jocelyne Neto de; Brito, MiguelSickle 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. A total of 66 stool samples were obtained and sequenced for the 16S rRNA gene (V3-V4 regions). Significant associations were observed in alpha and beta-diversity, with higher values of species richness for the children naïve for HU. We also noticed that children after HU had higher proportions of several beneficial bacteria, mostly short-chain fatty acids (SCFAs) producing species, such as Blautia luti, Roseburia inulinivorans, Eubacterium halli, Faecalibacterium, Ruminococcus, Lactobacillus rogosae, among others. In addition, before HU there was a higher abundance of Clostridium_g24, which includes C. bolteae and C. clostridioforme, both considered pathogenic. This study provides the first evidence of the HU effect on the gut microbiome and unravels several microorganisms that could be considered candidate biomarkers for disease severity and HU efficacy.
- Gut microbiota impact on Angolan children with sickle cell diseasePublication . Brito, Miguel; Delgadinho, Mariana; Ginete, Catarina; Mendes, Joana; Vasconcelos, J.; Santos, BrígidaIntroduction: Clinical manifestations of Sickle cell disease (SCD) are very heterogeneous, and the intestinal microbiome appears to be crucial in the modulation of inflammation, cell adhesion, and induction of aged neutrophils, which are the main interveners of recurrent vaso-occlusive crisis. Enterocyte injury, increased permeability, altered microbial composition, and bacterial overgrowth have all been documented as microbial and pathophysiologic changes in the gut microbiome of SCD patients in recent research studies. Microbiota analysis in SCD populations will be essential to demonstrate the importance of specific bacteria and their function in this disease and provide new insights for attenuating symptoms and new drug targets. Purpose: Given this, our aim is to sequence by NGS bacterial 16S RNA gene in order to characterize the gut microbiome of SCD children and healthy siblings, as a control.
- Efficacy and safety of pharmacological interventions for managing sickle cell disease in children and adolescents: protocol for a systematic review with network meta-analysisPublication . Tonin, Fernanda; Ginete, Catarina; Fernandez-Llimos, Fernando; Ferreira, Joana; Delgadinho, Mariana; Brito, MiguelIntroduction: Sickle cell disease (SCD), an inherited haemoglobinopathy, has an important impact on morbidity and mortality, especially in paediatrics. Previous systematic reviews are limited to adult patients or focused only on a few therapies. We aim to synthesise the evidence on the efficacy and safety of pharmacological interventions for managing SCD in children and adolescents. Methods and analysis: This systematic review protocol is available at Open Science Framework (doi:10.17605/OSF.IO/CWAE9). We will follow international recommendations on the conduction and report of systematic reviews and meta-analyses. Searches will be conducted in PubMed, Scopus, and Web of Science (no language nor time restrictions) (first pilot searches performed in May 2022). We will include randomised controlled trials comparing the effects of disease-modifying agents in patients with SCD under 18 years old. Outcomes of interest will include: vaso-occlusive crisis, haemoglobin levels, chest syndrome, stroke, overall survival, and adverse events. We will provide a narrative synthesis of the findings, and whenever possible, results will be pooled by means of pairwise or Bayesian network meta-analyses with the surface under the cumulative ranking curve analyses. Different statistical methods and models will be tested. Dichotomous outcomes will be reported as OR, risk ratio, or HR, while continuous data will be reported as standard mean differences, both with 95% CI/credibility interval. The methodological quality of the trials will be evaluated using the Risk of Bias 2.0 tool, and the certainty of the evidence will be assessed with the Grading of Recommendations Assessment, Development, and Evaluation approach. Ethics and dissemination: This study refers to a systematic review, so no ethics approval is necessary. We intend to publish our findings in an international, peer-reviewed journal. Data will also be presented to peers at scientific events. Additionally, the results obtained in this study may contribute towards the update of therapeutic guidelines and the development of health policies for SCD.
- Efficacy and safety of pharmacological interventions for managing sickle cell disease complications in children and adolescents: systematic review with network meta‐analysisPublication . Tonin, Fernanda; Ginete, Catarina; Ferreira, Joana; Delgadinho, Mariana; Santos, Brígida; Fernandez‐Llimos, Fernando; Brito, MiguelThis 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, the surface under the cumulative ranking curve (SUCRA) and stochastic multicriteria acceptability analyses (SMAA) (CRD42022328471). Eighteen 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.e., lower probabilities of incidence of this event; 14, 25, and 30%, respectively), acute chest syndrome (probabilities ranging from 8 to 30%), and needing of transfusions (11-31%), while l-arginine (100-200 mg/kg) and placebo were more prone to these events. Therapies were overall considered safe; however, antiplatelets and sulfates may lead to more severe adverse events. Although the evidence was graded as insufficient and weak, hydroxyurea remains the standard of care for this population, especially if a maximum tolerated dose schedule is considered.
- Sickle cell disease and gut health: the influence of intestinal parasites and the microbiome on Angolan childrenPublication . Delgadinho, Mariana; Ginete, Catarina; Santos, Brígida; Vasconcelos, Jocelyne Neto; Arez, Ana Paula; Brito, MiguelParasitic infections are a common problem in developing countries and can intensify morbidity in patients with sickle cell disease (SCD), increasing the severity of anemia and the need for transfusions. It has been demonstrated that both helminths and protozoa can affect gut microbiome composition. On the other hand, the presence of specific bacterial communities can also influence parasite establishment. Considering this, our aim was to associate the presence of intestinal parasites with the results of hematological analyses and microbiome composition evaluations in a population of Angolan children with and without SCD. A total of 113 stool samples were collected, and gut microbiome analysis was performed using 16S sequencing and real-time PCR to detect eight different intestinal parasites. In our population, more than half of children (55%) had at least one parasitic infection, and of these, 43% were co-infected. Giardia intestinalis and Ascaris lumbricoides were more frequently found in children from the rural area of Bengo. Moreover, SCD children with ascariasis exhibited higher values of leukocytes and neutrophils, whereas the total hemoglobin levels were lower. In regards to the gut microbiome, the presence of intestinal parasites lowered the prevalence of some beneficial bacteria, namely: Lactobacillus, Bifidobacterium, Cuneatibacter, Bacteroides uniformis, Roseburia, and Shuttleworthia. This study presents the prevalence of several intestinal parasites in a high-risk transmission area with scarce information and opens new perspectives for understanding the interaction between parasites, the microbiome, and SCD.
- The gut microbiome and hydroxyurea effect on sickle cell disease children from AngolaPublication . Brito, Miguel; Delgadinho, Mariana; Ginete, Catarina; Santos, Brígida; Vasconcelos, J.Background: Sickle cell disease (SCD) is an inherited hematological disorder and a serious global health problem, affecting between 20 and 25 million people worldwide. In Sub-Saharan Africa, where it is more prevalent, it contributes up to 90% of under-5 mortality. Although hydroxyurea (HU) is the leading treatment for these patients, its effects on the gut microbiome have not yet been explored. Some studies reported that gastroenteritis events were less frequent in SCA children taking HU and it also significantly improved the survival from pneumococcal infections. HU may have a protective effect, not only by improving several hematological parameters but also by lowering the risk of some bacterial infections. Aims: 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 and comparing it with a control group of healthy siblings. Results: A total of 113 fecal samples were obtained and sequenced by NGS for the 16S rRNA gene (V3-V4 regions), which corresponded to 40 children in the control and before HU groups and 33 after HU, aged between 4-12 years old. Our findings revealed that these three groups exhibit some notable differences, especially within Lachnospiraceae and Ruminococcaceae family. After HU treatment there was an increase of several beneficial bacteria, such as: Blautia coccoides (p=0.009), Blautia luti (p<0.001), Blautia faecis (p=0.008), Bifidobacterium longum (p=0.011), Dorea formicigenerans (p<0.001), Dorea massiliensis (p=0.003), Eubacterium halii (p=0.004), Elusimicrobium spp (p=0.032), Ruminococcus callidus (p=0.037), Ruminococcus faecis (p=0.012), Roseburia spp (p=0.050) and Subdoligranulum variabile (p=0.009). Most of those OTUs are SCFAs producing species, having butyrate or propionate as end-products of bacterial metabolism, both exhibiting anti-inflammatory properties. Moreover, children before HU had a higher abundance of bacteria considered pathogenic, like E. coli (p=0.001), Clostridiun_g24 (p=0.039), and H. influenzae (p=0.050). Conclusion: Overall, this study provides the first evidence of the HU effect on the gut microbiome and provides a rationale for further research for developing treatments to reduce gut microbiota-driven inflammation, which may attenuate the dysbiosis and chronic symptoms experienced by these patients.
- Microbial gut evaluation in an angolan paediatric population with sickle cell diseasePublication . Delgadinho, Mariana; Ginete, Catarina; Santos, Brígida; Mendes, Joana; Miranda, Armandina; Vasconcelos, Jocelyne; Brito, MiguelSickle cell disease (SCD) is one of the most common genetic conditions worldwide. It can contribute to 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. Enterocyte injury, increased permeability, altered microbial composition, and bacterial overgrowth have all been documented as microbial and pathophysiologic changes in the gut microbiome of SCD patients in recent studies. Our aim was to sequence the bacterial 16S rRNA gene in order to characterize the gut microbiome of Angolan children with SCA and healthy siblings as a control. A total of 72 stool samples were obtained from children between 3 and 14 years old. Our data showed that the two groups exhibit some notable differences in microbiota relative abundance at different classification levels. Children with SCA have a higher number of the phylum Actinobacteria. As for the genus level, Clostridium cluster XI bacteria was more prevalent in the SCA children, whereas the siblings had a higher abundance of Blautia, Aestuariispira, Campylobacter, Helicobacter, Polaribacter, and Anaerorhabdus. In this study, we have presented the first microbiota analysis in an Angolan paediatric population with SCD and provided a detailed view of the microbial differences between patients and healthy controls. There is still much to learn before fully relying on the therapeutic approaches for gut modulation, which is why more research in this field is crucial to making this a reality.
- Genetic modulation of anemia severity, hemolysis level, and hospitalization rate in Angolan children with sickle cell anemiaPublication . Germano, Isabel; Santos, Brígida; Delgadinho, Mariana; Ginete, Catarina; Lopes, Pedro; Arez, Ana Paula; Brito, Miguel; Faustino, PaulaBackground: Sickle Cell Anemia (SCA) is a genetic disease caused by the c.20 A > T mutation in the HBB gene, generally characterized by sickle erythrocytes, chronic hemolytic anemia, and vaso-occlusive events. This study aimed to investigate genetic modulators of anemia severity, chronic hemolytic rate, and clinical manifestations in pediatric SCA patients from Angola, where the disease is a severe public health problem. Methods and Results: The study was conducted on 200 SCA children living in Luanda or Caxito province. Their clinical phenotype was collected from patients' hospital records. Hematological and biochemical phenotypes were characterized in steady-state conditions. Twelve polymorphic regions in VCAM1, CD36, and NOS3 genes were genotyped using PCR, RFLP, and Sanger sequencing. CD36 gene promoter variants showed a significant impact on anemia severity. Particularly, the rs1413661_C allele was associated with lower hemoglobin levels and an increased number of hospitalizations and transfusions. This is the first report associating this SNP with SCA phenotypic heterogeneity. Moreover, the rs1041163_C allele in VCAM1 was associated with lower LDH levels; inversely the rs2070744_C allele in NOS3 was related to higher LDH levels and a number of hospitalizations, being a risk factor for increased hemolytic rate. Conclusion: This study highlights, for the first time in the Angolan population, the importance of the genetic modifiers of vascular cell adhesion and nitric oxide metabolism in SCA pediatric phenotypic variability.
- Comparative efficacy and safety of pharmacological interventions for sickle cell disease in children and adolescents: a network meta-analysisPublication . Tonin, Fernanda; Ginete, Catarina; Ferreira, J.; Delgadinho, Mariana; Fernandez-Llimos, Fernando; Brito, MiguelBackground: Sickle cell disease (SCD), an inherited hemoglobinopathy characterized by anemia, severe pain, acute chest syndrome (ACS), and vaso-occlusive crisis (VOC), has an important impact on morbidity and mortality worldwide, especially in the pediatric population (over 50% die before age of 5). Although few treatment options are available, new disease-modifying therapies, intended to prevent or reduce SCD-related complications are under development. Previous systematic reviews are limited to adult patients or focused only on gathering data on a few therapies. Aims: Our aim was to synthetize the evidence on the efficacy and safety profiles of pharmacological interventions for managing SCD in children and adolescents. Methods: A systematic review with searches in PubMed, Scopus, and Web of Science was performed (May-2022). The protocol is registered at PROSPERO CRD42022328471. We included randomized controlled trials comparing any disease-modifying agent used to treat SCD complications in patients under 18 years old. The outcomes of interest included: VOC, ACS, transfusions, hospital admission, discontinuation, and serious adverse events. Data were pooled by means of Bayesian network meta-analyses with the surface under the cumulative ranking curve analyses (SUCRA). Results were reported as odds ratio (OR) with 95% credibility intervals (CrI). Additionally, stochastic multicriteria acceptability analyses (SMAA) were performed. The methodological quality of the trials and certainty of evidence were evaluated through RoB 2.0 tool and the GRADE approach, respectively. Results: Overall, 17 randomized controlled trials (n=1,972 patients) published between 1982-2022, conducted mostly in Africa (41%) and North America (35%) were included for analyses. Around one-third of the trials were restricted to homozygous patients for the SCD allele (SS HMZ); yet when reported, patients with heterozygous S-C combination represented less than 30% of the population. Males accounted for 49.0% of the cases, with ages varying from 1 to 19 years old. Almost all trials (n=15, 88.2%) directly compared active drugs with placebo. The evaluated interventions were: hydroxyurea [n=6 trials], L-arginine [n=3], antiplatelets [n=2], immunotherapy/monoclonal antibodies [n=2], sulfates [n=2], docosahexaenoic acid [n=1], niprisan [n=1] (Figure 1). SUCRA and SMAA revealed that immunotherapy/monoclonal antibodies and hydroxyurea 20 mg/kg are potentially more effective against ACS (17% and 24% probabilities, respectively), VOC (around 29% and 20%, respectively) and needing of transfusions (around 25%), while L-arginine (100-200 mg/kg) and placebo were more associated with these events. Although therapies were overall considered safe, antiplatelet and sulfates may lead to more discontinuations and severe adverse events (uncertainty evidence). Results were similar between age subgroups (<10 years vs. 10-19 years). Summary - Conclusion: The available evidence on the effect of drugs on managing SCD in children and adolescents is still insufficient and weak. No clear definition and reporting criteria for some outcomes exist. Hydroxyurea 20 mg/kg/day may remain the standard of care for these patients, however, long-term, well-designed trials comparing new immunotherapy/monoclonal antibodies should be performed. The use of monotherapies with L-arginine, antiplatelets, or sulfates should be avoided given the poor benefit-risk ratio for this population.