The malaria parasites Plasmodium falciparum and Plasmodium vivax generate significant concentrations of free unbound ferrous iron heme as a side product of hemoglobin degradation. The presence of these chemically reactive forms of iron, rare in healthy cells, presents an opportunity for parasite-selective drug delivery. Accordingly, our group is developing technologies for the targeted delivery of therapeutics to the intra-erythrocytic malaria parasite. These so-called ‘fragmenting hybrids’ employ a 1,2,4-trioxolane ring system as an iron(II)-sensing ‘trigger’ moiety and a ‘traceless’ retro-Michael linker to which a variety of partner drug species may be attached. After ferrous iron-promoted activation in the parasite, the partner drug is released via a β-elimination reaction.
In this report, we describe three orthogonal experimental approaches that were explored in order to generate in vitro proof-of-concept for ferrous iron-dependent drug delivery from a prototypical fragmenting hybrid.
Studies of two fragmenting hybrids by orthogonal approaches confirm that a partner drug species can be delivered to live P. falciparum parasites. A key advantage of this approach is the potential to mask a partner drug’s intrinsic bioactivity prior to release in the parasite.
Among key potential drug target proteolytic systems in the malaria parasite Plasmodium falciparum are falcipains, a family of hemoglobin-degrading cysteine proteases, and the ubiquitin proteasomal system (UPS), which has fundamental importance in cellular protein turnover. Inhibition of falcipains blocks parasite development, primarily due to inhibition of hemoglobin degradation that serves as a source of amino acids for parasite growth. Falcipains prefer P2 leucine in substrates and peptides, and their peptidyl inhibitors with leucine at the P2 position show potent antimalarial activity. The peptidyl inhibitor MG132 (Z-Leu-Leu-Leu-CHO) is a widely used proteasome inhibitor, which also has P2 leucine, and has also been shown to inhibit parasite development. However, the antimalarial targets of MG132 are unclear. We investigated whether MG132 blocks malaria parasite development by inhibiting hemoglobin degradation and/or by targeting the UPS. P. falciparum was cultured with inhibitors of the UPS (MG132, epoxomicin, and lactacystin) or falcipains (E64), and parasites were assessed for morphologies, extent of hemoglobin degradation, and accumulation of ubiquitinated proteins. MG132, like E64 and unlike epoxomicin or lactacystin, blocked parasite development, with enlargement of the food vacuole and accumulation of undegraded hemoglobin, indicating inhibition of hemoglobin degradation by MG132, most likely due to inhibition of hemoglobin-degrading falcipain cysteine proteases. Parasites cultured with epoxomicin or MG132 accumulated ubiquitinated proteins to a significantly greater extent than untreated or E64-treated parasites, indicating that MG132 inhibits the parasite UPS as well. Consistent with these findings, MG132 inhibited both cysteine protease and UPS activities present in soluble parasite extracts, and it strongly inhibited recombinant falcipains. MG132 was highly selective for inhibition of P. falciparum (IC50 0.0476 µM) compared to human peripheral blood mononuclear cells (IC50 10.8 µM). Thus, MG132 inhibits two distinct proteolytic systems in P. falciparum, and it may serve as a lead molecule for development of dual-target inhibitors of malaria parasites.
Cholestasis predisposes to fat-soluble vitamin (FSV) deficiencies. A liquid multiple FSV preparation made with tocopheryl polyethylene glycol-1000 succinate (TPGS) is frequently used in infants with biliary atresia (BA) because of ease of administration and presumed efficacy. In this prospective multicenter study, we assessed the prevalence of FSV deficiency in infants with BA who received this FSV/TPGS preparation.
Infants received FSV/TPGS coadministered with additional vitamin K as routine clinical care in a randomized double-blinded, placebo-controlled trial of corticosteroid therapy after hepatoportoenterostomy (HPE) for BA (identifier NCT 00294684). Levels of FSV, retinol binding protein, total serum lipids, and total bilirubin (TB) were measured 1, 3, and 6 months after HPE.
Ninety-two infants with BA were enrolled in this study. Biochemical evidence of FSV insufficiency was common at all time points for vitamin A (29%–36% of patients), vitamin D (21%–37%), vitamin K (10%–22%), and vitamin E (16%–18%). Vitamin levels were inversely correlated with serum TB levels. Biochemical FSV insufficiency was much more common (15%–100% for the different vitamins) in infants whose TB was ≥2 mg/dL. At 3 and 6 months post HPE, only 3 of 24 and 0 of 23 infants, respectively, with TB >2 mg/dL were sufficient in all FSV.
Biochemical FSV insufficiency is commonly observed in infants with BA and persistent cholestasis despite administration of a TPGS containing liquid multiple FSV preparation. Individual vitamin supplementation and careful monitoring are warranted in infants with BA, especially those with TB >2 mg/dL.
cholestasis; nutrition; liver; vitamin deficiency
In long-term follow-up, 18-67% of pediatric liver transplant recipients are overweight or obese— with rates varying by age and pre-transplant weight status. Similar prevalence of post-transplant obesity is seen in adults. Adults also develop post-transplant metabolic syndrome, with consequent cardiovascular disease, at rates that exceed age and gender-matched populations. Post-transplant metabolic syndrome has never been studied in pediatric liver transplant recipients—a growing population as transplant outcomes continue to improve. This paper systematically reviews the literature on each component of metabolic syndrome—obesity, hypertension, dyslipidemia, and glucose intolerance—in pediatric liver transplant recipients. Rates of obesity are similar to that of the general U.S. population of children. But hypertension, dyslipidemia, and diabetes are more common than expected for age, gender, and obesity severity in transplant recipients. Immunosuppressive medications are major contributors. Limitations of prior studies—including heterogeneous methods of diagnosis, follow-up times, and immunosuppressive regimen—hinder the analysis of risk factors. Importantly, no studies report on graft or patient outcomes associated with metabolic syndrome components after pediatric liver transplant. However, if trends in children are similar to those seen in adults, these conditions may lead to significant long-term morbidity. Further research on the prevalence, causes, and consequences of post-transplant metabolic syndrome in pediatric liver transplant is needed and ultimately will help improve long-term outcomes.
pediatric; liver transplant; metabolic syndrome; obesity; hypertension; dyslipidemia; diabetes mellitus; insulin resistance
There is relatively little information in the literature on the histopathology of chronic hepatitis C in children. The Peds-C Trial, designed to test the efficacy and safety of peginterferon alfa-2a and ribavirin in children, provided an opportunity to examine liver biopsies from 121 treatment-naïve children, ages 2 to 16 (mean, 9.8 years) infected with the hepatitis C virus (HCV) and with no other identifiable cause for liver disease, signs of hepatic decompensation, or another significant nonhepatic disease. Liver biopsies were scored for inflammation, fibrosis, steatosis, and other histological features. Inflammation in the biopsy was minimal in 42%, mild in 17%, moderate in 38%, and severe in only 3%. Five had bridging fibrosis, and 2 had cirrhosis. Steatosis was absent in 56%, minimal in 34%, and mild in 10%. Inflammation scores correlated with fibrosis scores, serum alanine aminotransferase levels, and duration of infection, but not with age, body mass index z score, or HCV genotype. Fibrosis scores correlated with inflammation but not with age, HCV genotype, body mass index z score, or steatosis parameters. Steatosis correlated with serum alanine aminotransferase levels and body mass index z scores; overweight children had more fibrosis than the non-overweight. In conclusion, in this cohort of HCV-infected children, inflammation, fibrosis, and steatosis were milder than reported for treatment-naïve adults with chronic hepatitis C, but there were several with bridging fibrosis or cirrhosis. The positive correlation of inflammation with duration of infection and fibrosis and of obesity with fibrosis suggest that children with chronic hepatitis C will be at risk for progressive liver disease as they age and possibly acquire other comorbid risk factors.
Hepatitis B virus (HBV) is a major human pathogen that causes immune-mediated hepatitis. Successful immunity to HBV is age dependent: viral clearance occurs in most adults, whereas neonates and young children usually develop chronic infection. Using a mouse model of HBV infection, we sought mechanisms underpinning the age-dependent outcome of HBV and demonstrated that hepatic macrophages facilitate lymphoid organization and immune priming within the adult liver and promote successful immunity. In contrast, lymphoid organization and immune priming was greatly diminished in the livers of young mice, and of macrophage-depleted adult mice, leading to abrogated HBV immunity. Furthermore, we found that CXCL13, which is involved in B lymphocyte trafficking and lymphoid architecture and development, is expressed in an age-dependent manner in both adult mouse and human hepatic macrophages and plays an integral role in facilitating an effective immune response against HBV. Taken together, these results identify some of the immunological mechanisms necessary for effective control of HBV.
Weight loss and changes in growth are noted in children treated with interferonα
To prospectively determine changes in weight, height, body mass index and body composition during and after treatment of children with hepatitis C.
Children treated with PEG-IFNα2a +/− ribavirin in the PEDS-C trial underwent anthropometric measurements, DXA scan, dietary and activity assessments during and after treatment.
114 (55% male) children mean age 11±3 years were randomized, and 107 received treatment for at least 24 weeks. Subjects were divided into 3 groups according to duration of treatment: 24 (N=14), 48 (N=82), or 72 (N=11) weeks. Decrements of up to 0.50 z score were observed for weight, height and BMI while on therapy among all groups (P≤0.01 compared to baseline). In the group treated for 48 weeks, 29 (33%) subjects had greater than 0.5 unit decrement in height-for-age Z score. While weight-for-age and BMI z scores returned to baseline after cessation of therapy, mean HAZ score was slower to rebound, still lower than baseline at 96 weeks post-therapy for the long treatment duration group (P=0.03) and lower than baseline in most children treated for 48 weeks. Percent body fat, fat-free mass z scores and triceps skinfold z scores decreased with therapy. Dietary energy intake and levels of physical activity did not change during treatment.
PEG-IFNα2a was associated with significant changes in body weight, linear growth, body mass index and body composition in children. These effects were generally reversible with cessation of therapy, although height-for-age z scores had not returned to baseline after 2 years of observation in many. Longer term growth data are needed among children treated for chronic HCV.
Adjacent segment pathology affects 25% of patients within ten years of anterior cervical diskectomy and fusion (ACDF). Laboratory studies demonstrate fused segments increase adjacent level stress including elevated intradiscal pressure and increased range of motion. Radiographic adjacent segment pathology (RASP) has been associated to ACDF in multiple statistically significant studies. Randomized controlled trials (RCTs) comparing anterior cervical discectomy and arthroplasty (ACDA) and ACDF have confirmed ACDF accelerates RASP. The question of greatest clinical interest is whether ACDA, artificial disc surgery, results in fewer adjacent level surgeries than ACDF. Current RCT follow up results reveal only non statistically significant trends favoring ACDA yet the post operative periods are only two to four years. Statistically significant increased RASP in ACDF patients however is already documented. The RCT patients’ average ages are in the mid forties with an expected longevity of up to forty more years. Early statistically significant increased RASP in the ACDF patients supports our prediction that given sufficient follow up of ten or more years, fusion will lead to statistically significant higher rate of adjacent level surgery compared to artificial disc surgery.
Cervical; Diskectomy; Fusion; Arthroplasty; Adjacent; Degeneration
The hydroxynaphthoquinones have been extensively investigated over the past 50 years for their anti-malarial activity. One member of this class, atovaquone, is combined with proguanil in Malarone®, an important drug for the treatment and prevention of malaria.
Anti-malarial activity was assessed in vitro for a series of 3-alkyl-2-hydroxy-1,4-naphthoquinones (N1-N5) evaluating the parasitaemia after 48 hours of incubation. Potential cytotoxicity in HEK293T cells was assessed using the MTT assay. Changes in mitochondrial membrane potential of Plasmodium were measured using the fluorescent dye Mitrotracker Red CMXROS.
Four compounds demonstrated IC50s in the mid-micromolar range, and the most active compound, N3, had an IC50 of 443 nM. N3 disrupted mitochondrial membrane potential, and after 1 hour presented an IC50ΔΨmit of 16 μM. In an in vitro cytotoxicity assay using HEK 293T cells N3 demonstrated no cytotoxicity at concentrations up to 16 μM.
N3 was a potent inhibitor of mitochondrial electron transport, had nanomolar activity against cultured Plasmodium falciparum and showed minimal cytotoxicity. N3 may serve as a starting point for the design of new hydroxynaphthoquinone anti-malarials.
Plasmodium falciparum; Hydroxynaphthoquinone; 2-hydroxy-1,4-naphthoquinone; Mitochondria; Malaria; Plasmodium berghei
Human immunodeficiency virus (HIV) protease inhibitors show activity against Plasmodium falciparum in vitro. We hypothesized that the incidence of malaria in HIV-infected children would be lower among children receiving lopinavir–ritonavir–based antiretroviral therapy (ART) than among those receiving nonnucleoside reverse-transcriptase inhibitor (NNRTI)–based ART.
We conducted an open-label trial in which HIV-infected children 2 months to 5 years of age who were eligible for ART or were currently receiving NNRTI-based ART were randomly assigned to either lopinavir–ritonavir–based ART or NNRTI-based ART and were followed for 6 months to 2 years. Cases of uncomplicated malaria were treated with artemether–lumefantrine. The primary end point was the incidence of malaria.
We enrolled 176 children, of whom 170 received the study regimen: 86 received NNRTI-based ART, and 84 lopinavir–ritonavir–based ART. The incidence of malaria was lower among children receiving the lopinavir–ritonavir–based regimen than among those receiving the NNRTI-based regimen (1.32 vs. 2.25 episodes per person-year; incidence-rate ratio, 0.59; 95% confidence interval [CI], 0.36 to 0.97; P = 0.04), as was the risk of a recurrence of malaria after treatment with artemether–lumefantrine (28.1% vs. 54.2%; hazard ratio, 0.41; 95% CI, 0.22 to 0.76; P = 0.004). The median lumefantrine level on day 7 after treatment for malaria was significantly higher in the lopinavir–ritonavir group than in the NNRTI group. In the lopinavir–ritonavir group, lumefantrine levels exceeding 300 ng per milliliter on day 7 were associated with a reduction of more than 85% in the 63-day risk of recurrent malaria. A greater number of serious adverse events occurred in the lopinavir–ritonavir group than in the NNRTI group (5.6% vs. 2.3%, P = 0.16). Pruritus occurred significantly more frequently in the lopinavir–ritonavir group, and elevated alanine aminotransferase levels significantly more frequently in the NNRTI group.
Lopinavir–ritonavir–based ART as compared with NNRTI-based ART reduced the incidence of malaria by 41%, with the lower incidence attributable largely to a significant reduction in the recurrence of malaria after treatment with artemether–lumefantrine. Lopinavir–ritonavir–based ART was accompanied by an increase in serious adverse events. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ClinicalTrials.gov number, NCT00978068.)
Phosphonium lipocations were synthesized and evaluated for inhibition of the development of Plasmodium falciparum and Trypanosoma cruzi, etiological agents of malaria and Chagas disease, respectively. Optimal phthalimides and 1,4-naphthoquinone-based lipocations were active in vitro at mid-high nM concentrations against P. falciparum and low μM concentrations against T. cruzi.
Malaria; Chagas; Antiparasitic drugs; Plasmodium; Trypanosoma
Human immunodeficiency virus (HIV)-infected antiretroviral therapy-naive Ugandan children with CD4 cell counts of ∼350 cells/μL and percentages of >15% have significant motor and cognitive deficits compared with HIV-uninfected children. Study of whether early initiation of treatment could prevent or reverse such deficits is needed.
(See the Editorial Commentary by Wagner and Frenkel, on pages 1010–2.)
Background. Human immunodeficiency virus (HIV) infection causes neurocognitive or motor function deficits in children with advanced disease, but it is unclear whether children with CD4 cell measures above the World Health Organization (WHO) thresholds for antiretroviral therapy (ART) initiation suffer significant impairment.
Methods. The neurocognitive and motor functions of HIV-infected ART-naive Ugandan children aged 6–12 years with CD4 cell counts of >350 cells/μL and CD4 cell percentage of >15% were compared with those of HIV-uninfected children, using the Test of Variables of Attention (TOVA), the Kaufman Assessment Battery for Children, second edition (KABC-2), and the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2).
Results. Ninety-three HIV-infected children (median CD4 cell count, 655 cells/μL; plasma HIV RNA level, 4.7 log10 copies/mL) were compared to 106 HIV-uninfected children. HIV-infected children performed worse on TOVA visual reaction times (multivariate analysis of covariance; P = .006); KABC-2 sequential processing (P = .005), simultaneous processing (P = .039), planning/reasoning (P = .023), and global performance (P = .024); and BOT-2 total motor proficiency (P = .003). High plasma HIV RNA level was associated with worse performance in 10 cognitive measures and 3 motor measures. In analysis of only WHO clinical stage 1 or 2 HIV-infected children (n = 68), significant differences between the HIV-infected and HIV-uninfected groups (P < .05) remained for KABC-2 sequential processing, KABC-2 planning/reasoning, and BOT-2 motor proficiency.
Conclusions. Significant motor and cognitive deficits were found in HIV-infected ART-naive Ugandan children with CD4 cell counts of ∼350 cells/μL and percentages of >15%. Study of whether early initiation of ART could prevent or reverse such deficits is needed.
Background & Aims
Criteria for the diagnosis of autoimmune hepatitis (AIH) were formalized in 1993 and revised in 1999. Simplified criteria were developed in 2008, for adults only. We aimed to establish clinically useful diagnostic criteria for AIH in children by validating the 2008 criteria in a pediatric cohort.
Baseline data were available from 37 and 31 subjects with AIH (70% female) and 40 and 26 subjects without AIH (30% female), which were used to calculate the 1999 and 2008 criteria, respectively. Sensitivity and specificity of the simplified criteria were calculated using 1999 criteria as the standard for subjects with available data for both criteria.
The 1999 standard designated 29/31 subjects (94%) as definite AIH and 2/31 subjects (6%) as probable AIH. The simplified criteria identified 25/31 subjects (81%) as definite AIH, 2/31 subjects (6%) as probable AIH. Only 1/5 patients with AIH who presented with fulminant hepatic failure (FHF) was identified by the simplified criteria as having AIH. The 2008 diagnostic criteria had a sensitivity of 87% and specificity of 89% (area under the receiver operating characteristic [AUROC] curve=0.98). After removing data from patients with FHF from the analysis, the sensitivity increased to 100%. Modifying the 2008 diagnostic criteria to include either level of globulin or immunoglobulin (Ig)G resulted in similar sensitivity (92%) and specificity (95%; AUROC curve=0.99) values.
The 2008 criteria diagnose AIH in children with high levels of sensitivity and specificity, and are easier to use in the clinic. Diagnosis of AIH in patients who present in FHF requires the 1999 criteria. Levels of globulin and IgG can be used interchangeably in the simplified diagnostic criteria.
pediatric liver disease; scoring system; diagnostic; autoimmunity
Malaria remains one of the leading health problems of the developing world, and Uganda bears a particularly large burden from the disease. Our understanding is limited by a lack of reliable data, but it is clear that the prevalence of malaria infection, incidence of disease, and mortality from severe malaria all remain very high. Uganda has made progress in implementing key malaria control measures, in particular distribution of insecticide impregnated bednets, indoor residual spraying of insecticides, utilization of artemisinin-based combination therapy to treat uncomplicated malaria, and provision of intermittent preventive therapy for pregnant women. However, despite enthusiasm regarding the potential for the elimination of malaria in other areas, there is no convincing evidence that the burden of malaria has decreased in Uganda in recent years. Major challenges to malaria control in Uganda include very high malaria transmission intensity, inadequate health care resources, a weak health system, inadequate understanding of malaria epidemiology and the impact of control interventions, increasing resistance of parasites to drugs and of mosquitoes to insecticides, inappropriate case management, inadequate utilization of drugs to prevent malaria, and inadequate epidemic preparedness and response. Despite these challenges, prospects for the control of malaria have improved, and with attention to underlying challenges, progress toward the control of malaria in Uganda can be expected.
Malaria; Plasmodium; Uganda; Insecticide-treated nets; Indoor residual spraying; Artemisinin-based combination therapy; Intermittent preventive therapy
In the recent past there have been several reports of successes in malaria control, leading some public health experts to conclude that Africa is witnessing an epidemiological transition, from an era of failed malaria control to progression from successful control to elimination. Successes in control have been attributed to increased international donor support leading to increased intervention coverage. However, these changes are not uniform across Africa. In Uganda, where baseline transmission is very high and intervention coverage not yet to scale, the malaria burden is not declining and has even likely increased in the last decade. In this article we present perspectives for the future for Uganda and other malaria endemic countries with high baseline transmission intensity and significant health system challenges. For these high burden areas,malaria elimination is currently not feasible, and early elimination programs are inappropriate, as they would further fragment already fragmented and inefficient malaria control systems. Rather, health impacts will be maximized by aiming to achieve universal coverage of proven interventions in the context of a strengthened health system.
Malaria; Plasmodium; Uganda; Insecticide-treated nets; Indoor residual spraying; Artemisinin-based combination therapy; Intermittent preventive therapy; health systems
Biliary atresia (BA) is characterized by progressive inflammation and fibrosis of bile ducts. A theory of pathogenesis entails autoimmune-mediated injury targeting bile duct epithelia. One of the strongest genetic associations with autoimmunity is with HLA genes. In addition, apparently dissimilar HLA alleles may have similar antigen-binding sites, called shared epitopes, that overlap in their capacity to present antigens. In autoimmune disease, the incidence of the disease may be related to the presence of shared epitopes, not simply the HLA allelic association. Aim: To determine HLA allele frequency (high-resolution genotyping) and shared epitope associations in BA. Results: Analysis of every allele for HLA-A, -B, -C, -DRB1, -DPB1 and -DQB1 in 180 BA and 360 racially-matched controls did not identify any significant HLA association with BA. Furthermore, shared epitope analysis of greater than 10 million possible combinations of peptide sequences was not different between BA and controls. Conclusions: This study encompasses the largest HLA allele frequency analysis for BA in the United States and is the first study to perform shared epitope analysis. When controlling for multiple comparisons, no HLA allele or shared epitope association was identified in BA. Future studies of genetic links to BA that involve alterations of the immune response should include investigations into defects in regulatory T cells and non-HLA linked autoinflammatory diseases.
Electronic supplementary material
The online version of this article (doi:10.1186/2193-1801-2-42) contains supplementary material, which is available to authorized users.
HIV infection affects the clinical pattern of malaria. There is emerging evidence to suggest that previously documented interactions may be modified by recently scaled-up HIV and malaria interventions. Prophylaxis with trimethoprim–sulfamethoxazole (TS) in combination with use of insecticide-treated nets can markedly decrease the incidence of malaria in HIV-infected pregnant and nonpregnant adults and children even in the setting of antifolate resistance-conferring mutations that are currently common in Africa. Nonetheless, additional interventions are needed to protect HIV-infected people that reside in high-malaria-transmission areas. Artemether–lumefantrine and dihydroartemisinin–piperaquine are highly efficacious and safe for the treatment of uncomplicated malaria in HIV-infected persons. Coadministration of antiretroviral and antimalarial drugs creates the potential for pharmacokinetic drug interactions that may increase (causing enhancement of malaria treatment efficacy and post-treatment prophylaxis and/or unanticipated toxicity) or reduce (creating risk for treatment failure) antimalarial drug exposure. Further studies are needed to elucidate potentially important pharmacokinetic interactions between commonly used antimalarials, antiretrovirals and TS and their clinical implications. Data on the benefits of long-term TS prophylaxis among HIV patients on antiretroviral therapy who have achieved immune-reconstitution are limited. Studies to address these questions are ongoing or planned, and the results should provide the evidence base required to guide the prevention and treatment of malaria in HIV-infected patients.
antimalarial treatment; antiretroviral therapy; HIV infection; malaria; malaria prevention
The burden of malaria has decreased in parts of Africa following the scaling up of control interventions. However, similar data are limited from high transmission settings.
A cohort of 100 children, aged six weeks to 10 months of age, were enrolled in an area of high malaria transmission intensity and followed through 48 months of age. Children were given a long-lasting insecticide-treated bed net (LLIN) at enrolment and received all care, including monthly blood smears and treatment with artemisinin-based combination therapy (ACT) for uncomplicated malaria, at a dedicated clinic. The incidence of malaria was estimated by passive surveillance and associations between malaria incidence and age, calendar time and season were measured using generalized estimating equations.
Reported compliance with LLINs was 98% based on monthly routine evaluations. A total of 1,633 episodes of malaria were observed, with a median incidence of 5.3 per person-year (PPY). There were only six cases of complicated malaria, all single convulsions. Malaria incidence peaked at 6.5 PPY at 23 months of age before declining to 3.5 PPY at 48 months. After adjusting for age and season, the risk of malaria increased by 52% from 2008 to 2011 (RR 1.52, 95% CI 1.10-2.09). Asymptomatic parasitaemia was uncommon (monthly prevalence <10%) and rarely observed prior to 24 months of age.
In Tororo, despite provision of LLINs and prompt treatment with ACT, the incidence of malaria is very high and appears to be rising. Additional malaria control interventions in high transmission settings are likely needed.
Current Controlled Trials Identifier NCT00527800
Malaria; Plasmodium falciparum; Immunity; Epidemiology
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children in the United States. Although changes in diet are often recommended to improve NAFLD, little is known regarding diet influence on histologic features of the disease.
This was a prospective, cross-sectional registry based study. Children (n=149) enrolled in the multi-center NASH Clinical Research Network had demographic, anthropometric, clinical, laboratory and histology data obtained, including the Block Brief Food Questionnaire. Subjects were grouped by presence or absence of steatohepatitis and grades of histologic features according to NASH-CRN criteria.
No significant differences were found between children with steatosis compared to steatohepatitis for fraction of calories from fat, carbohydrates, and protein. Sugar sweetened beverage consumption was low and did not correlate with histologic features, although uric acid, a surrogate marker for fructose intake, was significantly increased in those with definite NASH (p=.008). For all groups, vitamin E consumption was insufficient compared to the recommended daily allowance. Median consumption of vitamin E was lower in children with higher grade of steatosis (8.4 vs 6.1 vs 6.9 for grade I, II and III respectively, p = .05). Those consuming less vitamin C had increased ballooning degeneration (p = 0.05).
Children with NAFLD have a diet that is insufficient in vitamin E and this may contribute to the pathophysiology of NAFLD. In children with NAFLD, reported sugar sweetened beverage consumption is low; however uric acid, which may reflect total fructose consumption, was significantly associated with NASH and should be further evaluated.
NASH; Nutrition; Vitamin C; Sugar Sweetened Beverages
Antibodies are important in the control of blood stage Plasmodium falciparum infection. It is unclear which antibody responses are responsible for, or even associated with protection, partly due to confounding by heterogeneous exposure. Assessment of response to partially effective antimalarial therapy, which requires the host to assist in clearing parasites, offers an opportunity to measure protection independent of exposure.
A cohort of children aged 1–10 years in Kampala, Uganda were treated with amodiaquine+sulfadoxine-pyrimethamine for uncomplicated malaria. Serum samples from the time of malaria diagnosis and 14 days later were analyzed for total IgG to 8 P. falciparum antigens using a quantitative indirect ELISA. Associations between antibody levels and risk of treatment failure were estimated using Cox proportional hazard regression.
Higher levels of antibodies to apical membrane antigen 1 (AMA-1), but to none of the other 7 antigens were significantly associated with protection against treatment failure (HR 0.57 per 10-fold increase in antibody level, CI 0.41–0.79, p = 0.001). Protection increased consistently across the entire range of antibody levels.
Measurement of antibody levels to AMA-1 at the time of malaria may offer a quantitative biomarker of blood stage immunity to P. falciparum, a tool which is currently lacking.
Discovering new lead compounds against malaria parasites is a crucial step to ensuring a sustainable global pipeline for effective anti-malarial drugs. As far as we know, no previous phytochemical or pharmacological investigations have been carried out on Sorindeia juglandifolia. This paper describes the results of an anti-malarial activity-driven investigation of the fruits of this Cameroonian plant.
Air-dried fruits were extracted by maceration using methanol. The extract was fractionated by flash chromatography followed by column chromatography over silica gel, eluting with gradients of hexane-ethyl acetate mixtures. Resulting fractions and compounds were tested in vitro against the Plasmodium falciparum chloroquine-resistant strain W2, against field isolates of P. falciparum, and against the P. falciparum recombinant cysteine protease falcipain-2. Promising fractions were assessed for acute toxicity after oral administration in mice. One of the promising isolated compounds was assessed in vivo against the rodent malaria parasite Plasmodium berghei.
The main end-products of the activity-guided fractionation were 2,3,6-trihydroxy benzoic acid (1) and 2,3,6-trihydroxy methyl benzoate (2). Overall, nine fractions tested against P. falciparum W2 and falcipain-2 were active, with IC50 values of 2.3-11.6 μg/ml for W2, and 1.1-21.9 μg/ml for falcipain-2. Purified compounds (1) and (2) also showed inhibitory effects against P. falciparum W2 (IC50s 16.5 μM and 13.0 μM) and falcipain-2 (IC50s 35.4 and 6.1 μM). In studies of P. falciparum isolates from Cameroon, the plant fractions demonstrated IC50 values of 0.14-19.4 μg/ml and compounds (1) and (2) values of 6.3 and 36.1 μM. In vivo assessment of compound (1) showed activity against P. berghei strain B, with mean parasitaemia suppressive dose and curative dose of 44.9 mg/kg and 42.2 mg/kg, respectively. Active fractions were found to be safe in mice after oral administration of 7 g/kg body weight.
Fractions of Sorindeia juglandifolia and two compounds isolated from these fractions were active against cultured malaria parasites, the P. falciparum protease falcipain-2, and in a rodent malaria model. These results suggest that further investigation of the anti-malarial activities of natural products from S. juglandifolia will be appropriate.
Malaria; Drug discovery; Sorindeia juglandifolia; Plasmodium falciparum; Plasmodium berghei
We compared the prevalence of key pfmdr1 alleles between pretreatment Plasmodium falciparum parasite isolates and parasites that emerged after treatment of uncomplicated malaria in a longitudinal cohort of Ugandan children. The pfmdr1 86N, 184F, and 1246D alleles were selected after treatment with artemether-lumefantrine, but not after artesunate-amodiaquine or amodiaquine-sulfadoxine-pyrimethamine. Remarkably, selection persisted in infections presenting up to about 60 days after treatment with artemether-lumefantrine. Thus, parasites selected for decreased drug sensitivity can appear long after predicted exposure to antimalarial drugs. Continued surveillance of the clinical efficacy and in vitro activity of new combination therapies is warranted.
Novel conjugates of the antimalarial drug primaquine (compound 1) with ferrocene, named primacenes, have been synthesized and screened for their activities against blood stage and liver stage malaria in vitro and host-vector transmission in vivo. Both transmission-blocking and blood-schizontocidal activities of the parent drug were conserved only in primacenes bearing a basic aliphatic amine group. Liver stage activity did not require this structural feature, and all metallocenes tested were comparable to or better than primaquine in this regard. Remarkably, the replacement of primaquine's aliphatic chain by hexylferrocene, as in compound 7, led to a ∼45-fold-higher level activity against liver stage parasitemia than that of primaquine.
Progressive familial intrahepatic cholestasis, type 2 (PFIC2), characterized by cholestasis in infancy that may progress to cirrhosis, is caused by mutation in ABCB11, which encodes bile salt export pump (BSEP). We correlated histopathologic, immunohistochemical, and ultrastructural features in PFIC2 with specific mutations and clinical course. Twelve patients with clinical PFIC2 and ABCB11 mutations were identified, and 22 liver biopsy and explant specimens were assessed. All had hepatocellular cholestasis; most had canalicular bile plugs. At least 1 specimen from every patient had centrizonal/sinusoidal fibrosis, often with periportal fibrosis. Neonatal hepatitis-like features (inflammation, giant cells, necrosis) varied. In 2 of the 5 patients with paired specimens obtained > 6 months apart, lobular and portal fibrosis worsened. Transmission electron microscopy (EM) in all 9 patients studied showed canalicular dilatation, microvilli loss, abnormal mitochondrial internal structure, and varying intra-canalicular accumulation of finely granular bile. Canalicular staining for BSEP was absent in 10 patients and present in 2 patients, 1 of whom had intermittent symptoms. ABCB11 sequencing of all patients identified 6 novel and 10 previously described mutations, with nonsense, missense, and/or noncoding mutations in the 10 patients without immunohistochemically demonstrable BSEP. Missense and/or noncoding mutations were identified in the 2 patients with demonstrable BSEP, whose clinical course was more indolent. Mutations ending ABCB11 transcription appear linked, through hepatocellular necrosis and fibrosis, to worse outcome. In conclusion, light microscopy and electron microscopy findings in clinical PFIC2 can support diagnosis, but are variable and nonspecific. Therefore, no correlation between specific mutations and histopathology is yet possible.
PFIC2; progressive familial intrahepatic cholestasis; bile salt export pump; BSEP; ABCB11; neonatal hepatitis