Ammonium Accumulation and Cell Death in a Rat 3D Brain Cell Model of Glutaric Aciduria Type I

Glutaric aciduria type I (glutaryl-CoA dehydrogenase deficiency) is an inborn error of metabolism that usually manifests in infancy by an acute encephalopathic crisis and often results in permanent motor handicap. Biochemical hallmarks of this disease are elevated levels of glutarate and 3-hydroxyglutarate in blood and urine. The neuropathology of this disease is still poorly understood, as low lysine diet and carnitine supplementation do not always prevent brain damage, even in early-treated patients. We used a 3D in vitro model of rat organotypic brain cell cultures in aggregates to mimic glutaric aciduria type I by repeated administration of 1 mM glutarate or 3-hydroxyglutarate at two time points representing different developmental stages. Both metabolites were deleterious for the developing brain cells, with 3-hydroxyglutarate being the most toxic metabolite in our model. Astrocytes were the cells most strongly affected by metabolite exposure. In culture medium, we observed an up to 11-fold increase of ammonium in the culture medium with a concomitant decrease of glutamine. We further observed an increase in lactate and a concomitant decrease in glucose. Exposure to 3-hydroxyglutarate led to a significantly increased cell death rate. Thus, we propose a three step model for brain damage in glutaric aciduria type I: (i) 3-OHGA causes the death of astrocytes, (ii) deficiency of the astrocytic enzyme glutamine synthetase leads to intracerebral ammonium accumulation, and (iii) high ammonium triggers secondary death of other brain cells. These unexpected findings need to be further investigated and verified in vivo. They suggest that intracerebral ammonium accumulation might be an important target for the development of more effective treatment strategies to prevent brain damage in patients with glutaric aciduria type I.     

Draft Genome Sequence Determination for Cystic Fibrosis and Chronic Granulomatous Disease Burkholderia multivorans Isolates

Burkholderia multivorans is a Gram-negative bacterium and a member of the Burkholderia cepacia complex, which is frequently associated with respiratory infections in people with cystic fibrosis (CF) and chronic granulomatous disease (CGD). We are reporting the genome sequences of 4 B. multivorans strains, 2 from CF patients and 2 from CGD patients.     

Clinical and immunological effects of Rituximab in patients with lupus nephritis refractory to conventional therapy: a pilot study

We studied the clinical and immunological effects of Rituximab (anti-CD20) therapy in patients with lupus nephritis. In an open clinical trial, 22 patients with active systemic lupus erythematosis and renal involvement (mainly class III and IV according to the WHO classification) that was refractory to conventional therapy were studied. In all these patients, Rituximab (0.5 to 1.0 g at days 1 and 15) was added to the immunosuppressive therapy and its therapeutic effect was evaluated. In addition, the levels and function of regulatory T lymphocytes and the apoptosis of immune cells were assessed. We found a significant reduction in disease activity (p < 0.05, MEX-SLEDAI index), and proteinuria (p < 0.05) at days 60 and 90 of Rituximab therapy. Although most patients showed improvement in creatinine clearance and erythrocyturia, no significant changes in these parameters were detected. In most patients (20/22), B cell depletion was observed, but no clear-cut effect of Rituximab on complement levels or auto-antibody titers was detected (p > 0.05 in all cases). One patient died at day 70 with invasive histoplasmosis. No important adverse effects of Rituximab therapy were registered in other patients. A significant enhancement in the levels of different CD4+ regulatory cells (T_REG, Th3, Tr1), but not CD8+ Ts lymphocytes, was observed at day 30. This increase was sustained for T_REG cells at day 90, and accompanied by an improvement in their regulatory function. In addition, we observed an unexpected increase in the apoptosis of T cells at day 30. Interestingly, the enhancement in the suppressive function of T_REG cells was not observed in the two patients that showed the poorest clinical response to Rituximab. We conclude that the data obtained in this open clinical trial suggest that Rituximab is a promising candidate for randomized controlled trials in patients with lupus nephritis refractory to the conventional immunosuppressive therapy. The effects of Rituximab on regulatory cells and apoptosis of T lymphocytes are interesting and its possible role in the putative effect of this biological agent in systemic lupus erythematosis deserves additional studies.     

Household Costs of Leprosy Reactions (ENL) in Rural India

Background

Erythema nodosum leprosum (ENL) is a common immune-mediated complication of lepromatous (LL) and borderline lepromatous (BL) leprosy. Most patients experience chronic or multiple acute ENL over many years during an economically active period of their lives. Understanding the economic burden of ENL is essential to provide effective patient support, yet this area has not been investigated.

Methods

Ninety-one patients with LL or BL leprosy attending a leprosy hospital in Purulia district of West Bengal, India, were interviewed using a structured questionnaire. Cases (n = 53) were identified as those who had one or more episodes of ENL within the last 3 years. Controls (n = 38) had LL or BL leprosy but no history of ENL. Data were collected on household income, direct and indirect costs, and coping strategies.

Findings

The total household cost was Rs 1543 per month or 27.9% (IQR 13.2-52.6) of monthly household income for cases, and Rs 237 per month or 4.9% (IQR 1.7-13.4) of monthly household income for controls. Indirect costs accounted for 65% of total household costs for cases. Direct costs accounted for the remaining 35% of household costs, and resulted almost entirely from treatment-seeking in the private sector. Total household costs exceeded 40% of household income for 37.7% of cases (n = 20) and 2.6% of controls (n = 1) [1 USD = 59 INR].

Interpretation

Households affected by ENL face significant economic burden and are at risk of being pushed further into poverty. Health policy should acknowledge the importance of private sector provision and the significant contribution to total household costs of lost productivity (indirect cost). Further work is needed to explore this area and identify solutions.     

Current status of the E23K Kir6.2 polymorphism: implications for type-2 diabetes

The ATP-sensitive potassium (K_ATP) channel couples membrane excitability to cellular metabolism and is a critical mediator in the process of glucose-stimulated insulin secretion. Increasing numbers of K_ATP channel polymorphisms are being described and linked to altered insulin secretion indicating that genes encoding this ion channel could be susceptibility markers for type-2 diabetes. Genetic variation of K_ATP channels may result in altered -cell electrical activity, glucose homeostasis, and increased susceptibility to type-2 diabetes. Of particular interest is the Kir6.2 E23K polymorphism, which is linked to increased susceptibility to type-2 diabetes in Caucasian populations and may also be associated with weight gain and obesity, both of which are major diabetes risk factors. This association highlights the potential contribution of both genetic and environmental factors to the development and progression of type-2 diabetes. In addition, the common occurrence of the E23K polymorphism in Caucasian populations may have conferred an evolutionary advantage to our ancestors. This review will summarize the current status of the association of K_ATP channel polymorphisms with type-2 diabetes, focusing on the possible mechanisms by which these polymorphisms alter glucose homeostasis and offering insights into possible evolutionary pressures that may have contributed to the high prevalence of K_ATP channel polymorphisms in the Caucasian population.This work was supported by funding from the Canadian Diabetes Association (CDA) in honor of Gordon M. Stevenson, the Alberta Heritage Foundation for Medical Research (AHFMR), and the Canadian Institutes of Health Research (CIHR). M.J.R. is supported by AHFMR and CDA Scholarships. P.E.L. received salary support as an AHFMR Scholar and CIHR New Investigator     

The impact of Neglected Tropical Diseases (NTDs) on health and wellbeing in sub-Saharan Africa (SSA): A case study of Kenya

Neglected Tropical Diseases (NTDs) remain endemic to many regions of sub-Saharan Africa (SSA) left behind by socioeconomic progress. As such, these diseases are markers of extreme poverty and inequity that are propagated by the political, economic, social, and cultural systems that affect health and wellbeing. As countries embrace and work towards achieving the Sustainable Development Goals (SDGs), the needs of such vulnerable populations need to be addressed in local and global arenas. The research uses primary qualitative data collected from five NTD endemic counties of Kenya: interviews key informants (n = 21) involved in NTD implementation programs and focus groups (n = 5) of affected individuals. Informed by theories of political ecology of health, the research focuses on post-devolution Kenya and identifies the political, economic, social, and cultural factors that propagate NTDs and their effects on health and wellbeing. Our findings indicate that structural factors such as competing political interests, health worker strikes, inadequate budgetary allocations, economic opportunity, marginalization, illiteracy, entrenched cultural norms and practices, poor access to water, sanitation and housing, all serve to propagate NTD transmission and subsequently affect the health and wellbeing of populations. As such, we recommend that post-devolution Kenya ensures local political, economic and socio-cultural structures are equitable, sensitive and responsive to the needs of all people. We also propose poverty alleviation through capacity building and empowerment as a means of tackling NTDs for sustained economic opportunity and productivity at the local and national level.     

Formation and antiproliferative effect of prostaglandin E(3) from eicosapentaenoic acid in human lung cancer cells

We investigated the formation and pharmacology of prostaglandin E(3) (PGE(3)) derived from fish oil eicosapentaenoic acid (EPA) in human lung cancer A549 cells. Exposure of A549 cells to EPA resulted in the rapid formation and export of PGE(3.) The extracellular ratio of PGE(3) to PGE(2) increased from 0.08 in control cells to 0.8 in cells exposed to EPA within 48 h. Incubation of EPA with cloned ovine or human recombinant cyclooxygenase 2 (COX-2) resulted in 13- and 18-fold greater formation of PGE(3), respectively, than that produced by COX-1. Exposure of A549 cells to 1 microM PGE(3) inhibited cell proliferation by 37.1% (P < 0.05). Exposure of normal human bronchial epithelial (NHBE) cells to PGE(3), however, had no effect. When A549 cells were exposed to EPA (25 microM) or a combination of EPA and celecoxib (a selective COX-2 inhibitor), the inhibitory effect of EPA on the growth of A549 cells was reversed by the presence of celecoxib (at both 5 and 10 microM). This effect appears to be associated with a 50% reduction of PGE(3) formation in cells treated with a combination of EPA and celecoxib compared with cells exposed to EPA alone. These data indicate that exposure of lung cancer cells to EPA results in a decrease in the COX-2-mediated formation of PGE(2), an increase in the level of PGE(3), and PGE(3)-mediated inhibition of tumor cell proliferation.     

Quantification of the elevated rate of domain rearrangements in metazoa

Most eukaryotic proteins consist of multiple domains created through gene fusions or internal duplications. The most frequent change of a domain architecture (DA) is insertion or deletion of a domain at the N or C terminus. Still, the mechanisms underlying the evolution of multidomain proteins are not very well studied.Here, we have studied the evolution of multidomain architectures (MDA), guided by evolutionary information in the form of a phylogenetic tree. Our results show that Pfam domain families and MDAs have been created with comparable rates (0.1-1 per million years (My)). The major changes in DA evolution have occurred in the process of multicellularization and within the metazoan lineage. In contrast, creation of domains seems to have been frequent already in the early evolution. Furthermore, most of the architectures have been created from older domains or architectures, whereas novel domains are mainly found in single-domain proteins. However, a particular group of exon-bordering domains may have contributed to the rapid evolution of novel multidomain proteins in metazoan organisms. Finally, MDAs have evolved predominantly through insertions of domains, whereas domain deletions are less common.In conclusion, the rate of creation of multidomain proteins has accelerated in the metazoan lineage, which may partly be explained by the frequent insertion of exon-bordering domains into new architectures. However, our results indicate that other factors have contributed as well.