Clostridium difficile infection.

Infection of the colon with the Gram-positive bacterium Clostridium difficile is potentially life threatening, especially in elderly people and in patients who have dysbiosis of the gut microbiota following antimicrobial drug exposure. C. difficile is the leading cause of health-care-associated infective diarrhoea. The life cycle of C. difficile is influenced by antimicrobial agents, the host immune system, and the host microbiota and its associated metabolites. The primary mediators of inflammation in C. difficile infection (CDI) are large clostridial toxins, toxin A (TcdA) and toxin B (TcdB), and, in some bacterial strains, the binary toxin CDT. The toxins trigger a complex cascade of host cellular responses to cause diarrhoea, inflammation and tissue necrosis - the major symptoms of CDI. The factors responsible for the epidemic of some C. difficile strains are poorly understood. Recurrent infections are common and can be debilitating. Toxin detection for diagnosis is important for accurate epidemiological study, and for optimal management and prevention strategies. Infections are commonly treated with specific antimicrobial agents, but faecal microbiota transplants have shown promise for recurrent infections. Future biotherapies for C. difficile infections are likely to involve defined combinations of key gut microbiota

A pre-specified analysis of the Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease (DAPA-CKD) randomized controlled trial on the incidence of abrupt declines in kidney function.

This pre-specified analysis of DAPA-CKD assessed the impact of sodium-glucose cotransporter 2 inhibition on abrupt declines in kidney function in high risk patients based on having chronic kidney disease (CKD) and severe albuminuria. DAPA-CKD was a randomized, double-blind, placebo-controlled trial had a median follow-up of 2.4 years. Adults with CKD (urinary albumin-to-creatinine ratio 200-5000 mg/g and estimated glomerular filtration rate 25-75 mL/min/1.73m2) were randomized to dapagliflozin 10 mg/day matched to placebo (2152 individuals each). An abrupt decline in kidney function was defined as a pre-specified endpoint of doubling of serum creatinine between two subsequent study visits. We also assessed a post-hoc analysis of investigator-reported acute kidney injury-related serious adverse events. Doubling of serum creatinine between two subsequent visits (median time-interval 100 days) occurred in 63 (2.9%) and 91 (4.2%) participants in the dapagliflozin and placebo groups, respectively (hazard ratio 0.68 [95% confidence interval 0.49, 0.94]). Accounting for the competing risk of mortality did not alter our findings. There was no heterogeneity in the effect of dapagliflozin on abrupt declines in kidney function based on baseline subgroups. Acute kidney injury-related serious adverse events were not significantly different and occurred in 52 (2.5%) and 69 (3.2%) participants in the dapagliflozin and placebo groups, respectively (0.77 [0.54, 1.10]). Thus, in patients with CKD and substantial albuminuria, dapagliflozin reduced the risk of abrupt declines in kidney function

Effects of Dapagliflozin in Chronic Kidney Disease, With and Without Other Cardiovascular Medications: DAPA-CKD Trial

Background The DAPA-CKD (Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease) trial (NCT03036150) demonstrated that dapagliflozin reduced the risk of kidney and cardiovascular events in patients with chronic kidney disease and albuminuria with and without type 2 diabetes. We aimed to determine whether baseline cardiovascular medication use modified the dapagliflozin treatment effect. Methods and Results We randomized 4304 adults with baseline estimated glomerular filtration rate 25 to 75 mL/min per 1.73 m2 and urinary albumin:creatinine ratio 200 to 5000 mg/g to dapagliflozin 10 mg or placebo once daily. The primary end point was a composite of ≥50% estimated glomerular filtration rate decline, end-stage kidney disease, and kidney or cardiovascular death. Secondary end points included a kidney composite end point (primary composite end point without cardiovascular death), a cardiovascular composite end point (hospitalized heart failure or cardiovascular death), and all-cause mortality. We categorized patients according to baseline cardiovascular medication use/nonuse. Patients were required by protocol to receive a stable (and maximally tolerated) dose of a renin-angiotensin-aldosterone system inhibitor. We observed consistent benefits of dapagliflozin relative to placebo, irrespective of baseline use/nonuse of renin-angiotensin-aldosterone system inhibitors (98.1%), calcium channel blockers (50.7%), β-adrenergic antagonists (39.0%), diuretics (43.7%), and antithrombotic (47.4%), and lipid-lowering (15.0%) agents. Use of these drugs in combination with dapagliflozin did not increase the number of serious adverse events. Conclusions The safety profile and efficacy of dapagliflozin on kidney and cardiovascular end points in patients with chronic kidney disease were consistent among patients treated and not treated at baseline with a range of cardiovascular medications. Registration Information clinicaltrials.gov. Identifier: NCT03036150

The Kidney Protective Effects of the Sodium–Glucose Cotransporter-2 Inhibitor, Dapagliflozin, Are Present in Patients With CKD Treated With Mineralocorticoid Receptor Antagonists

Introduction: Mineralocorticoid receptor antagonists (MRAs) and sodium-glucose cotransporter-2 (SGLT2) inhibitors reduce the risk of kidney failure in chronic kidney disease (CKD). We performed an analysis of the Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease (DAPA-CKD) trial by baseline conventional MRA (spironolactone and eplerenone) prescription. Methods: Participants with CKD (estimated glomerular filtration rate [eGFR] 25-75 ml/min per 1.73 m2; urinary albumin-to-creatinine ratio 200-500 mg/g), with or without type 2 diabetes, were randomized 1:1 to dapagliflozin 10 mg or placebo, once daily. The primary outcome was a composite of sustained ≥50% eGFR decline, end-stage kidney disease, or kidney or cardiovascular (CV) death. A prespecified kidney-specific secondary outcome was as the primary outcome but without CV death. Hyperkalemia (serum potassium ≥6.0 mmol/l) was an exploratory end point. Time-to-event analyses (proportional hazards [Cox] regression) assessed dapagliflozin versus placebo in patient subgroups defined by baseline conventional MRA use. Results: A total of 229 of 4304 DAPA-CKD participants (5.3%) were receiving conventional MRAs at baseline (dapagliflozin n = 109, placebo n = 120). The effect of dapagliflozin on the primary outcome was consistent in participants prescribed (hazard ratio [HR] 0.76, 95% CI 0.40-1.47) and not prescribed (HR 0.60, 95% CI 0.50-0.72, P-interaction = 0.59) MRAs. This consistency was maintained for the kidney-specific outcome. The effect of dapagliflozin on hyperkalemia (HR 0.87, 95% CI 0.70-1.09) was consistent among those prescribed (HR 0.94, 95% CI 0.41-2.20) and not prescribed (HR 0.87, 95% CI 0.69-1.10, P-interaction = 0.96) MRAs. Adverse events (AEs) leading to discontinuation and serious AEs were similar between treatment groups, regardless of baseline MRA prescription. Conclusion: Dapagliflozin was similarly safe and efficacious in reducing major adverse kidney outcomes in participants with CKD who were or were not prescribed MRAs at baseline

Safety and Allele-Specific Immunogenicity of a Malaria Vaccine in Malian Adults: Results of a Phase I Randomized Trial

OBJECTIVES: The objectives were to evaluate the safety, reactogenicity, and allele-specific immunogenicity of the blood-stage malaria vaccine FMP1/AS02A in adults exposed to seasonal malaria and the impact of natural infection on vaccine-induced antibody levels. DESIGN: We conducted a randomized, double-blind, controlled phase I clinical trial. SETTING: Bandiagara, Mali, West Africa, is a rural town with intense seasonal transmission of Plasmodium falciparum malaria. PARTICIPANTS: Forty healthy, malaria-experienced Malian adults aged 18–55 y were enrolled. INTERVENTIONS: The FMP1/AS02A malaria vaccine is a 42-kDa recombinant protein based on the carboxy-terminal end of merozoite surface protein-1 (MSP-1(42)) from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The control vaccine was a killed rabies virus vaccine (Imovax). Participants were randomized to receive either FMP1/AS02A or rabies vaccine at 0, 1, and 2 mo and were followed for 1 y. OUTCOME MEASURES: Solicited and unsolicited adverse events and allele-specific antibody responses to recombinant MSP-1(42) and its subunits derived from P. falciparum strains homologous and heterologous to the 3D7 vaccine strain were measured. RESULTS: Transient local pain and swelling were more common in the malaria vaccine group than in the control group (11/20 versus 3/20 and 10/20 versus 6/20, respectively). MSP-1(42) antibody levels rose during the malaria transmission season in the control group, but were significantly higher in malaria vaccine recipients after the second immunization and remained higher after the third immunization relative both to baseline and to the control group. Immunization with the malaria vaccine was followed by significant increases in antibodies recognizing three diverse MSP-1(42) alleles and their subunits. CONCLUSIONS: FMP1/AS02A was well tolerated and highly immunogenic in adults exposed to intense seasonal malaria transmission and elicited immune responses to genetically diverse parasite clones. Anti-MSP-1(42) antibody levels followed a seasonal pattern that was significantly augmented and prolonged by the malaria vaccine

Children with hemoglobin C or S trait have low serologic responses to a subset of malaria variant surface antigens

Summary Children with hemoglobin AC or AS have decreased susceptibility to clinical malaria. Parasite variant surface antigen (VSA) presentation on the surface of infected erythrocytes is altered in erythrocytes with hemoglobin C (Hb AC) or sickle trait (Hb AS) mutations in vitro. The protective role of incomplete or altered VSA presentation against clinical malaria in individuals with Hb AC or AS is unclear. Using a high-throughput protein microarray, we sought to use serological responses to VSAs as a measure of host exposure to VSAs among Malian children with Hb AC, Hb AS, or wildtype hemoglobin (Hb AA). In uncomplicated malaria, when compared to Hb AA children, Hb AC children had significantly lower serological responses to extracellular Plasmodium falciparum erythrocyte membrane protein-1 (PfEMP1) domains but did not differ in responses to intracellular PfEMP1 domains and other VSAs, including members of the repetitive interspersed family (RIFIN) and subtelomeric variable open reading frame (STEVOR) family. Healthy children with Hb AC and Hb AS genotypes recognized fewer extracellular PfEMP1s compared to children with Hb AA, especially CD36-binding PfEMP1s. These reduced serologic responses may reflect reduced VSA presentation or lower parasite exposure in children with Hb AC or AS and provide insights into mechanisms of protection

Anaemia in a phase 2 study of a blood stage falciparum malaria vaccine

<p>Abstract</p> <p>Background</p> <p>A Phase 1-2b study of the blood stage malaria vaccine AMA1-C1/Alhydrogel was conducted in 336 children in Donéguébougou and Bancoumana, Mali. In the Phase 2 portion of the study (n = 300), no impact on parasite density or clinical malaria was seen; however, children who received the study vaccine had a higher frequency of anaemia (defined as haemoglobin < 8.5 g/dL) compared to those who received the comparator vaccine (Hiberix). This effect was one of many tested and was not significant after adjusting for multiple comparisons.</p> <p>Methods</p> <p>To further investigate the possible impact of vaccination on anaemia, additional analyses were conducted including patients from the Phase 1 portion of the study and controlling for baseline haemoglobin, haemoglobin types S or C, alpha-thalassaemia, G6PD deficiency, and age. A multiplicative intensity model was used, which generalizes Cox regression to allow for multiple events. Frailty effects for each subject were used to account for correlation of multiple anaemia events within the same subject. Intensity rates were calculated with reference to calendar time instead of time after randomization in order to account for staggered enrollment and seasonal effects of malaria incidence. Associations of anaemia with anti-AMA1 antibody were further explored using a similar analysis.</p> <p>Results</p> <p>A strong effect of vaccine on the incidence of anaemia (risk ratio [AMA1-C1 to comparator (Hiberix)]= 2.01, 95% confidence interval [1.26,3.20]) was demonstrated even after adjusting for baseline haemoglobin, haemoglobinopathies, and age, and using more sophisticated statistical models. Anti-AMA1 antibody levels were not associated with this effect.</p> <p>Conclusions</p> <p>While these additional analyses show a robust effect of vaccination on anaemia, this is an intensive exploration of secondary results and should, therefore, be interpreted with caution. Possible mechanisms of the apparent adverse effect on haemoglobin of vaccination with AMA1-C1/Alhydrogel and implications for blood stage vaccine development are discussed. The potential impact on malaria-associated anaemia should be closely evaluated in clinical trials of AMA1 and other blood stage vaccines in malaria-exposed populations.</p

Effects of dapagliflozin in chronic kidney disease, with and without other cardiovascular medications: DAPA-CKD trial

Background: The DAPA‐CKD (Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease) trial (NCT03036150) demonstrated that dapagliflozin reduced the risk of kidney and cardiovascular events in patients with chronic kidney disease and albuminuria with and without type 2 diabetes. We aimed to determine whether baseline cardiovascular medication use modified the dapagliflozin treatment effect. Methods and Results: We randomized 4304 adults with baseline estimated glomerular filtration rate 25 to 75 mL/min per 1.73 m2 and urinary albumin:creatinine ratio 200 to 5000 mg/g to dapagliflozin 10 mg or placebo once daily. The primary end point was a composite of ≥50% estimated glomerular filtration rate decline, end‐stage kidney disease, and kidney or cardiovascular death. Secondary end points included a kidney composite end point (primary composite end point without cardiovascular death), a cardiovascular composite end point (hospitalized heart failure or cardiovascular death), and all‐cause mortality. We categorized patients according to baseline cardiovascular medication use/nonuse. Patients were required by protocol to receive a stable (and maximally tolerated) dose of a renin‐angiotensin‐aldosterone system inhibitor. We observed consistent benefits of dapagliflozin relative to placebo, irrespective of baseline use/nonuse of renin‐angiotensin‐aldosterone system inhibitors (98.1%), calcium channel blockers (50.7%), β‐adrenergic antagonists (39.0%), diuretics (43.7%), and antithrombotic (47.4%), and lipid‐lowering (15.0%) agents. Use of these drugs in combination with dapagliflozin did not increase the number of serious adverse events. Conclusions: The safety profile and efficacy of dapagliflozin on kidney and cardiovascular end points in patients with chronic kidney disease were consistent among patients treated and not treated at baseline with a range of cardiovascular medications. Registration Information: clinicaltrials.gov. Identifier: NCT03036150

Safety and Immunogenicity of an AMA-1 Malaria Vaccine in Malian Adults: Results of a Phase 1 Randomized Controlled Trial

The objective was to evaluate the safety, reactogenicity and immunogenicity of the AMA-1-based blood-stage malaria vaccine FMP2.1/AS02A in adults exposed to seasonal malaria.A phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02A is a recombinant protein (FMP2.1) based on apical membrane antigen-1 (AMA-1) from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert). Sixty healthy, malaria-experienced adults aged 18-55 y were recruited into 2 cohorts and randomized to receive either a half dose or full dose of the malaria vaccine (FMP2.1 25 microg/AS02A 0.25 mL or FMP2.1 50 microg/AS02A 0.5 mL) or rabies vaccine given in 3 doses at 0, 1 and 2 mo, and were followed for 1 y. Solicited symptoms were assessed for 7 d and unsolicited symptoms for 30 d after each vaccination. Serious adverse events were assessed throughout the study. Titers of anti-AMA-1 antibodies were measured by ELISA and P. falciparum growth inhibition assays were performed on sera collected at pre- and post-vaccination time points. Transient local pain and swelling were common and more frequent in both malaria vaccine dosage groups than in the comparator group. Anti-AMA-1 antibodies increased significantly in both malaria vaccine groups, peaking at nearly 5-fold and more than 6-fold higher than baseline in the half-dose and full-dose groups, respectively.The FMP2.1/AS02A vaccine had a good safety profile, was well-tolerated, and was highly immunogenic in malaria-exposed adults. This malaria vaccine is being evaluated in Phase 1 and 2 trials in children at this site

Two complement receptor one alleles have opposing associations with cerebral malaria and interact with ethalassaemia

Malaria has been a major driving force in the evolution of the human genome. In sub-Saharan African populations, two neighbouring polymorphisms in the Complement Receptor One (CR1) gene, named Sl2 and McCb, occur at high frequencies, consistent with selection by malaria. Previous studies have been inconclusive. Using a large case-control study of severe malaria in Kenyan children and statistical models adjusted for confounders, we estimate the relationship between Sl2 and McCb and malaria phenotypes, and find they have opposing associations. The Sl2 polymorphism is associated with markedly reduced odds of cerebral malaria and death, while the McCb polymorphism is associated with increased odds of cerebral malaria. We also identify an apparent interaction between Sl2 and α+thalassaemia, with the protective association of Sl2 greatest in children with normal α-globin. The complex relationship between these three mutations may explain previous conflicting findings, highlighting the importance of considering genetic interactions in disease-association studies