Decline in Kidney Function among Apparently Healthy Young Adults at Risk of Mesoamerican Nephropathy.

Background Epidemic levels of CKD of undetermined cause, termed Mesoamerican nephropathy in Central America, have been found in low- and middle-income countries. We investigated the natural history of, and factors associated with, loss of kidney function in a population at high risk for this disease.Methods We conducted a 2-year prospective, longitudinal study with follow-up every 6 months in nine rural communities in northwestern Nicaragua and included all men (n=263) and a random sample of women (n=87) ages 18-30 years old without self-reported CKD, diabetes, or hypertension. We used growth mixture modeling to identify subgroups of eGFR trajectory and weighted multinomial logistic regression to examine associations with proposed risk factors.Results Among men, we identified three subpopulations of eGFR trajectory (mean baseline eGFR; mean eGFR change over follow-up): 81% remained stable (116 ml/min per 1.73 m2; -0.6 ml/min per 1.73 m2 per year), 9.5% experienced rapid decline despite normal baseline function (112 ml/min per 1.73 m2; -18.2 ml/min per 1.73 m2 per year), and 9.5% had baseline dysfunction (58 ml/min per 1.73 m2; -3.8 ml/min per 1.73 m2 per year). Among women: 96.6% remained stable (121 ml/min per 1.73 m2; -0.6 ml/min per 1.73 m2 per year), and 3.4% experienced rapid decline (132 ml/min per 1.73 m2; -14.6 ml/min per 1.73 m2 per year; n=3 women). Among men, outdoor and agricultural work and lack of shade availability during work breaks, reported at baseline, were associated with rapid decline.Conclusions Although Mesoamerican nephropathy is associated with agricultural work, other factors may also contribute to this disease.

Rationale, description and baseline findings of a community-based prospective cohort study of kidney function amongst the young rural population of Northwest Nicaragua.

BACKGROUND: An epidemic of Mesoamerican Nephropathy (MeN) is killing thousands of agricultural workers along the Pacific coast of Central America, but the natural history and aetiology of the disease remain poorly understood. We have recently commenced a community-based longitudinal study to investigate Chronic Kidney Disease (CKD) in Nicaragua. Although logistically challenging, study designs of this type have the potential to provide important insights that other study designs cannot. In this paper we discuss the rationale for conducting this study and summarize the findings of the baseline visit. METHODS: The baseline visit of the community-based cohort study was conducted in 9 communities in the North Western Nicaragua in October and November 2014. All of the young men, and a random sample of young women (aged 18-30) without a pre-existing diagnosis of CKD were invited to participate. Glomerular filtration rate (eGFR) was estimated with CKD-EPI equation, along with clinical measurements, questionnaires, biological and environmental samples to evaluate participants' exposures to proposed risk factors for MeN. RESULTS: We identified 520 young adults (286 males and 234 females) in the 9 different communities. Of these, 16 males with self-reported CKD and 5 females with diagnoses of either diabetes or hypertension were excluded from the study population. All remaining 270 men and 90 women, selected at random, were then invited to participate in the study; 350 (97%) agreed to participate. At baseline, 29 (11%) men and 1 (1%) woman had an eGFR <90 mL/min/1.73 m2. CONCLUSION: Conducting a community based study of this type requires active the involvement of communities and commitment from local leaders. Furthermore, a research team with strong links to the area and broad understanding of the context of the problem being studied is essential. The key findings will arise from follow-up, but it is striking that 5% of males under aged 30 had to be excluded because of pre-existing kidney disease, and that despite doing so 11% of males had an eGFR <90 mL/min/1.73 m2 at baseline.

Camelid heavy chain only antibody fragment domain against ß-site of amyloid precursor protein cleaving enzyme 1 inhibits ß-secretase activity in vitro and in vivo.

UNLABELLED: Accumulation and aggregation of the amyloid-ß (Aß) peptide is associated with Alzheimer's disease (AD). Aß is generated from the amyloid precursor protein by the successive action of two membrane-associated processing enzymes: ß-secretase or ß-site of amyloid precursor protein cleaving enzyme 1 (BACE1) and γ-secretase. Inhibition of one or both of these enzymes prevents Aß generation and the accompanying Aß accumulation. Antigen binding fragments from camelid heavy chain only antibodies (VHHs) were found to exert excellent enzyme inhibition activity. In the present study, we generated VHHs against BACE1 by active immunization of Lama glama with the recombinant BACE1 protein. Two classes of VHHs were selected from a VHH-phage display library by competitive elution with a peptide encoding the Swedish mutation variant of the BACE1 processing site. One VHH was found to inhibit the enzyme activity of BACE1 in vitro and in cell culture, whereas two other VHHs were found to stimulate BACE1 activity under the same conditions in vitro. Furthermore, an in vivo study with a transgenic AD mouse model, using intracisternal injection of the inhibitory VHH, led to acute reduction of the Aß load in the blood and brain. This inhibitory VHH may be considered as a candidate molecule for a therapy directed towards reduction of Aß load and prevention of AD progression. Both the inhibitory and stimulatory VHH may be useful for improving our understanding of the structure-function relationship of BACE1, as well as its role in AD progression. DATABASE: The GenBank sequence accession numbers are KR363186 for VHH B1a; KR363187 for VHH B3a; and KR363188 for VHH B5a.

Simple colorimetric trypanothione reductase-based assay for high-throughput screening of drugs against Leishmania intracellular amastigotes.

Critical to the search for new anti-leishmanial drugs is the availability of high-throughput screening (HTS) methods to test chemical compounds against the relevant stage for pathogenesis, the intracellular amastigotes. Recent progress in automated microscopy and genetic recombination has produced powerful tools for drug discovery. Nevertheless, a simple and efficient test for measuring drug activity against Leishmania clinical isolates is lacking. Here we describe a quantitative colorimetric assay in which the activity of a Leishmania native enzyme is used to assess parasite viability. Enzymatic reduction of disulfide trypanothione, monitored by a microtiter plate reader, was used to quantify the growth of Leishmania parasites. An excellent correlation was found between the optical density at 412 nm and the number of parasites inoculated. Pharmacological validation of the assay was performed against the conventional alamarBlue method for promastigotes and standard microscopy for intracellular amastigotes. The activity of a selected-compound panel, including several anti-leishmanial reference drugs, demonstrated high consistency between the newly developed assay and the reference method and corroborated previously published data. Quality assessment with standard measures confirmed the robustness and reproducibility of the assay, which performed in compliance with HTS requirements. This simple and rapid assay provides a reliable, accurate method for screening anti-leishmanial agents, with high throughput. The basic equipment and manipulation required to perform the assay make it easy to implement, simplifying the method for scoring inhibitor assays.